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Sample records for conserved cysteine residues

  1. Role of conserved cysteine residues in Herbaspirillum seropedicae NifA activity.

    Science.gov (United States)

    Oliveira, Marco A S; Baura, Valter A; Aquino, Bruno; Huergo, Luciano F; Kadowaki, Marco A S; Chubatsu, Leda S; Souza, Emanuel M; Dixon, Ray; Pedrosa, Fábio O; Wassem, Roseli; Monteiro, Rose A

    2009-01-01

    Herbaspirillum seropedicae is an endophytic diazotrophic bacterium that associates with economically important crops. NifA protein, the transcriptional activator of nif genes in H. seropedicae, binds to nif promoters and, together with RNA polymerase-sigma(54) holoenzyme, catalyzes the formation of open complexes to allow transcription initiation. The activity of H. seropedicae NifA is controlled by ammonium and oxygen levels, but the mechanisms of such control are unknown. Oxygen sensitivity is attributed to a conserved motif of cysteine residues in NifA that spans the central AAA+ domain and the interdomain linker that connects the AAA+ domain to the C-terminal DNA binding domain. Here we mutagenized this conserved motif of cysteines and assayed the activity of mutant proteins in vivo. We also purified the mutant variants of NifA and tested their capacity to bind to the nifB promoter region. Chimeric proteins between H. seropedicae NifA, an oxygen-sensitive protein, and Azotobacter vinelandii NifA, an oxygen-tolerant protein, were constructed and showed that the oxygen response is conferred by the central AAA+ and C-terminal DNA binding domains of H. seropedicae NifA. We conclude that the conserved cysteine motif is essential for NifA activity, although single cysteine-to-serine mutants are still competent at binding DNA.

  2. Loss of second and sixth conserved cysteine residues from trypsin inhibitor-like cysteine-rich domain-type protease inhibitors in Bombyx mori may induce activity against microbial proteases.

    Science.gov (United States)

    Li, Youshan; Liu, Huawei; Zhu, Rui; Xia, Qingyou; Zhao, Ping

    2016-12-01

    Previous studies have indicated that most trypsin inhibitor-like cysteine-rich domain (TIL)-type protease inhibitors, which contain a single TIL domain with ten conserved cysteines, inhibit cathepsin, trypsin, chymotrypsin, or elastase. Our recent findings suggest that Cys 2nd and Cys 6th were lost from the TIL domain of the fungal-resistance factors in Bombyx mori, BmSPI38 and BmSPI39, which inhibit microbial proteases and the germination of Beauveria bassiana conidia. To reveal the significance of these two missing cysteines in relation to the structure and function of TIL-type protease inhibitors in B. mori, cysteines were introduced at these two positions (D36 and L56 in BmSPI38, D38 and L58 in BmSPI39) by site-directed mutagenesis. The homology structure model of TIL domain of the wild-type and mutated form of BmSPI39 showed that two cysteine mutations may cause incorrect disulfide bond formation of B. mori TIL-type protease inhibitors. The results of Far-UV circular dichroism (CD) spectra indicated that both the wild-type and mutated form of BmSPI39 harbored predominantly random coil structures, and had slightly different secondary structure compositions. SDS-PAGE and Western blotting analysis showed that cysteine mutations affected the multimerization states and electrophoretic mobility of BmSPI38 and BmSPI39. Activity staining and protease inhibition assays showed that the introduction of cysteine mutations dramaticly reduced the activity of inhibitors against microbial proteases, such as subtilisin A from Bacillus licheniformis, protease K from Engyodontium album, protease from Aspergillus melleus. We also systematically analyzed the key residue sites, which may greatly influence the specificity and potency of TIL-type protease inhibitors. We found that the two missing cysteines in B. mori TIL-type protease inhibitors might be crucial for their inhibitory activities against microbial proteases. The genetic engineering of TIL-type protease inhibitors may be

  3. Highly Conserved Arg Residue of ERFNIN Motif of Pro-Domain is Important for pH-Induced Zymogen Activation Process in Cysteine Cathepsins K and L.

    Science.gov (United States)

    Aich, Pulakesh; Biswas, Sampa

    2018-06-01

    Pro-domain of a cysteine cathepsin contains a highly conserved Ex 2 Rx 2 Fx 2 Nx 3 Ix 3 N (ERFNIN) motif. The zymogen structure of cathepsins revealed that the Arg(R) residue of the motif is a central residue of a salt-bridge/H-bond network, stabilizing the scaffold of the pro-domain. Importance of the arginine is also demonstrated in studies where a single mutation (Arg → Trp) in human lysosomal cathepsin K (hCTSK) is linked to a bone-related genetic disorder "Pycnodysostosis". In the present study, we have characterized in vitro Arg → Trp mutant of hCTSK and the same mutant of hCTSL. The R → W mutant of hCTSK revealed that this mutation leads to an unstable zymogen that is spontaneously activated and auto-proteolytically degraded rapidly. In contrast, the same mutant of hCTSL is sufficiently stable and has proteolytic activity almost like its wild-type counterpart; however it shows an altered zymogen activation condition in terms of pH, temperature and time. Far and near UV circular dichroism and intrinsic tryptophan fluorescence experiments have revealed that the mutation has minimal effect on structure of the protease hCTSL. Molecular modeling studies shows that the mutated Trp31 in hCTSL forms an aromatic cluster with Tyr23 and Trp30 leading to a local stabilization of pro-domain and supplements the loss of salt-bridge interaction mediated by Arg31 in wild-type. In hCTSK-R31W mutant, due to presence of a non-aromatic Ser30 residue such interaction is not possible and may be responsible for local instability. These differences may cause detrimental effects of R31W mutation on the regulation of hCTSK auto-activation process compared to altered activation process in hCTSL.

  4. Substitution of cysteine for a conserved alanine residue in the catalytic center of type II iodothyronine deiodinase alters interaction with reducing cofactor

    NARCIS (Netherlands)

    W. Klootwijk (Willem); T.J. Visser (Theo); G.G.J.M. Kuiper (George)

    2002-01-01

    textabstractHuman type II iodothyronine deiodinase (D2) catalyzes the activation of T(4) to T(3). The D2 enzyme, like the type I (D1) and type III (D3) deiodinases, contains a selenocysteine (SeC) residue (residue 133 in D2) in the highly conserved catalytic center. Remarkably, all

  5. Key Role of Cysteine Residues in Catalysis and Subcellular Localization of Sulfur Oxygenase-Reductase of Acidianus tengchongensis

    DEFF Research Database (Denmark)

    Chen, Z. W.; Jiang, C. Y.; She, Qunxin

    2005-01-01

    ). The thio-modifying reagent N-ethylmaleimide and Zn2+ strongly inhibited the activities of the SORs of A. tengchongensis, suggesting that cysteine residues are important. Site-directed mutagenesis was used to construct four mutant SORs with cysteines replaced by serine or alanine. The purified mutant......Analysis of known sulfur oxygenase-reductases (SORs) and the SOR-like sequences identified from public databases indicated that they all possess three cysteine residues within two conserved motifs (V-G-P-K-V-C31 and C101-X-X-C104; numbering according to the Acidianus tengchongensis numbering system...... proteins were investigated in parallel with the wild-type SOR. Replacement of any cysteine reduced SOR activity by 98.4 to 100%, indicating that all the cysteine residues are crucial to SOR activities. Circular-dichroism and fluorescence spectrum analyses revealed that the wild-type and mutant SORs have...

  6. Carbon Nanotubes Facilitate Oxidation of Cysteine Residues of Proteins.

    Science.gov (United States)

    Hirano, Atsushi; Kameda, Tomoshi; Wada, Momoyo; Tanaka, Takeshi; Kataura, Hiromichi

    2017-10-19

    The adsorption of proteins onto nanoparticles such as carbon nanotubes (CNTs) governs the early stages of nanoparticle uptake into biological systems. Previous studies regarding these adsorption processes have primarily focused on the physical interactions between proteins and nanoparticles. In this study, using reduced lysozyme and intact human serum albumin in aqueous solutions, we demonstrated that CNTs interact chemically with proteins. The CNTs induce the oxidation of cysteine residues of the proteins, which is accounted for by charge transfer from the sulfhydryl groups of the cysteine residues to the CNTs. The redox reaction simultaneously suppresses the intermolecular association of proteins via disulfide bonds. These results suggest that CNTs can affect the folding and oxidation degree of proteins in biological systems such as blood and cytosol.

  7. The role of cysteine residues in the sulphate transporter, SHST1: construction of a functional cysteine-less transporter.

    Science.gov (United States)

    Howitt, Susan M

    2005-05-20

    We investigated the role of cysteine residues in the sulphate transporter, SHST1, with the aim of generating a functional cysteine-less variant. SHST1 contains five cysteine residues and none was essential for function. However, replacement of C421 resulted in a reduction in transport activity. Sulphate transport by C205 mutants was dependent on the size of the residue at this position. Alanine at position 205 resulted in a complete loss of function whereas leucine resulted in a 3-fold increase in sulphate transport relative to wild type SHST1. C205 is located in a putative intracellular loop and our results suggest that this loop may be important for sulphate transport. By replacing C205 with leucine and the other four cysteine residues with alanine, we constructed a cysteine-less variant of SHST1 that has transport characteristics indistinguishable from wild type. This construct will be useful for further structure and function studies of SHST1.

  8. Electrostatics of cysteine residues in proteins: Parameterization and validation of a simple model

    Science.gov (United States)

    Salsbury, Freddie R.; Poole, Leslie B.; Fetrow, Jacquelyn S.

    2013-01-01

    One of the most popular and simple models for the calculation of pKas from a protein structure is the semi-macroscopic electrostatic model MEAD. This model requires empirical parameters for each residue to calculate pKas. Analysis of current, widely used empirical parameters for cysteine residues showed that they did not reproduce expected cysteine pKas; thus, we set out to identify parameters consistent with the CHARMM27 force field that capture both the behavior of typical cysteines in proteins and the behavior of cysteines which have perturbed pKas. The new parameters were validated in three ways: (1) calculation across a large set of typical cysteines in proteins (where the calculations are expected to reproduce expected ensemble behavior); (2) calculation across a set of perturbed cysteines in proteins (where the calculations are expected to reproduce the shifted ensemble behavior); and (3) comparison to experimentally determined pKa values (where the calculation should reproduce the pKa within experimental error). Both the general behavior of cysteines in proteins and the perturbed pKa in some proteins can be predicted reasonably well using the newly determined empirical parameters within the MEAD model for protein electrostatics. This study provides the first general analysis of the electrostatics of cysteines in proteins, with specific attention paid to capturing both the behavior of typical cysteines in a protein and the behavior of cysteines whose pKa should be shifted, and validation of force field parameters for cysteine residues. PMID:22777874

  9. Targeting cysteine residues of human immunodeficiency virus type 1 protease by reactive free radical species.

    Science.gov (United States)

    Basu, A; Sehajpal, P K; Ogiste, J S; Lander, H M

    1999-01-01

    Nitric oxide (NO) is a naturally occurring free radical with many functions. The oxidized form of NO, the nitrosonium ion, reacts with the thiol group of cysteine residues resulting in their modification to S-nitrosothiols. The human immunodeficiency virus type 1 (HIV-1) protease (HIV-PR) has two cysteine residues that are conserved amongst different viral isolates found in patients with acquired immunodeficiency syndrome (AIDS). In an active dimer, these residues are located near the surface of the protease. We have found that treatment of HIV-PR with different NO congeners results in loss of its proteolytic activity and simultaneous formation of S-nitrosothiols. Sodium nitroprusside inhibited HIV-PR up to 70% and S-nitroso-N-acetylpenicillamine completely inhibited the protease within 5 min of treatment. The pattern of inhibition by NO donors is comparable to its inhibition by N-acetyl pepstatin. Using electrospray ionization-mass spectrometry, we identified the modification of HIV-PR by NO as that of S-nitrosation. Our findings point towards a possible role of NO in mediating resistance to HIV-1 infection.

  10. Site-directed Mutagenesis of Cysteine Residues in Phi-class Glutathione S-transferase F3 from Oryza sativa

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Hyunjoo; Lee, Juwon; Noh, Jinseok; Kong, Kwanghoon [Chung-Ang Univ., Seoul (Korea, Republic of)

    2012-12-15

    To elucidate the roles of cysteine residues in rice Phi-class GST F3, in this study, all three cysteine residues were replaced with alanine by site-directed mutagenesis in order to obtain mutants C22A, C73A and C77A. Three mutant enzymes were expressed in Escherichia coli and purified to electrophoretic homogeneity by affinity chromatography on immobilized GSH. The substitutions of Cys73 and Cys77 residues in OsGSTF3 with alanine did not affect the glutathione conjugation activities, showing non-essentiality of these residues. On the other hand, the substitution of Cys22 residue with alanine resulted in approximately a 60% loss of specific activity toward ethacrynic acid. Moreover, the K{sub m}{sup CDNB} value of the mutant C22A was approximately 2.2 fold larger than that of the wild type. From these results, the evolutionally conserved cysteine 22 residue seems to participate rather in the structural stability of the active site in OsGSTF3 by stabilizing the electrophilic substrates-binding site's conformation than in the substrate binding directly.

  11. Electrostatics of cysteine residues in proteins: parameterization and validation of a simple model.

    Science.gov (United States)

    Salsbury, Freddie R; Poole, Leslie B; Fetrow, Jacquelyn S

    2012-11-01

    One of the most popular and simple models for the calculation of pK(a) s from a protein structure is the semi-macroscopic electrostatic model MEAD. This model requires empirical parameters for each residue to calculate pK(a) s. Analysis of current, widely used empirical parameters for cysteine residues showed that they did not reproduce expected cysteine pK(a) s; thus, we set out to identify parameters consistent with the CHARMM27 force field that capture both the behavior of typical cysteines in proteins and the behavior of cysteines which have perturbed pK(a) s. The new parameters were validated in three ways: (1) calculation across a large set of typical cysteines in proteins (where the calculations are expected to reproduce expected ensemble behavior); (2) calculation across a set of perturbed cysteines in proteins (where the calculations are expected to reproduce the shifted ensemble behavior); and (3) comparison to experimentally determined pK(a) values (where the calculation should reproduce the pK(a) within experimental error). Both the general behavior of cysteines in proteins and the perturbed pK(a) in some proteins can be predicted reasonably well using the newly determined empirical parameters within the MEAD model for protein electrostatics. This study provides the first general analysis of the electrostatics of cysteines in proteins, with specific attention paid to capturing both the behavior of typical cysteines in a protein and the behavior of cysteines whose pK(a) should be shifted, and validation of force field parameters for cysteine residues. Copyright © 2012 Wiley Periodicals, Inc.

  12. Fasting, but Not Aging, Dramatically Alters the Redox Status of Cysteine Residues on Proteins in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Katja E. Menger

    2015-06-01

    Full Text Available Altering the redox state of cysteine residues on protein surfaces is an important response to environmental challenges. Although aging and fasting alter many redox processes, the role of cysteine residues is uncertain. To address this, we used a redox proteomic technique, oxidative isotope-coded affinity tags (OxICAT, to assess cysteine-residue redox changes in Drosophila melanogaster during aging and fasting. This approach enabled us to simultaneously identify and quantify the redox state of several hundred cysteine residues in vivo. Cysteine residues within young flies had a bimodal distribution with peaks at ∼10% and ∼85% reversibly oxidized. Surprisingly, these cysteine residues did not become more oxidized with age. In contrast, 24 hr of fasting dramatically oxidized cysteine residues that were reduced under fed conditions while also reducing cysteine residues that were initially oxidized. We conclude that fasting, but not aging, dramatically alters cysteine-residue redox status in D. melanogaster.

  13. Do cysteine residues regulate transient receptor potential canonical type 6 (TRPC6) channel protein expression?

    DEFF Research Database (Denmark)

    Thilo, Florian; Liu, Ying; Krueger, Katharina

    2012-01-01

    The regulation of calcium influx through transient receptor potential canonical type 6 channel is mandatory for the activity of human monocytes. We submit the first evidence that cysteine residues of homocysteine or acetylcysteine affect TRPC6 expression in human monocytes. We observed that patie......The regulation of calcium influx through transient receptor potential canonical type 6 channel is mandatory for the activity of human monocytes. We submit the first evidence that cysteine residues of homocysteine or acetylcysteine affect TRPC6 expression in human monocytes. We observed...... that patients with chronic renal failure had significantly elevated homocysteine levels and TRPC6 mRNA expression levels in monocytes compared to control subjects. We further observed that administration of homocysteine or acetylcysteine significantly increased TRPC6 channel protein expression compared...... to control conditions. We therefore hypothesize that cysteine residues increase TRPC6 channel protein expression in humans....

  14. Covalent binding of nitrogen mustards to the cysteine-34 residue in human serum albumin

    NARCIS (Netherlands)

    Noort, D.; Hulst, A.G.; Jansen, R.

    2002-01-01

    Covalent binding of various clinically important nitrogen mustards to the cysteine-34 residue of human serum albumin, in vitro and in vivo, is demonstrated. A rapid method for detection of these adducts is presented, based on liquid chromatography-tandem mass spectrometry analysis of the adducted

  15. CONSTRUCTION OF A FUNCTIONAL LACTOSE PERMEASE DEVOID OF CYSTEINE RESIDUES

    NARCIS (Netherlands)

    VANIWAARDEN, PR; PASTORE, JC; KONINGS, WN; KABACK, HR

    1991-01-01

    By use of oligonucleotide-directed, site-specific mutagenesis, a lactose (lac) permease molecule was constructed in which all eight cysteinyl residues were simultaneously mutagenized (C-less permease). Cys154 was replaced with valine, and Cys117, -148, -176, -234, -333, -353, and -355 were replaced

  16. The selenazal drug ebselen potently inhibits indoleamine 2,3-dioxygenase by targeting enzyme cysteine residues.

    Science.gov (United States)

    Terentis, Andrew C; Freewan, Mohammed; Sempértegui Plaza, Tito S; Raftery, Mark J; Stocker, Roland; Thomas, Shane R

    2010-01-26

    The heme enzyme indoleamine 2,3-dioxygenase (IDO) plays an important immune regulatory role by catalyzing the oxidative degradation of l-tryptophan. Here we show that the selenezal drug ebselen is a potent IDO inhibitor. Exposure of human macrophages to ebselen inhibited IDO activity in a manner independent of changes in protein expression. Ebselen inhibited the activity of recombinant human IDO (rIDO) with an apparent inhibition constant of 94 +/- 17 nM. Optical and resonance Raman spectroscopy showed that ebselen altered the active site heme of rIDO by inducing a transition of the ferric heme iron from the predominantly high- to low-spin form and by lowering the vibrational frequency of the Fe-CO stretch of the CO complex, indicating an opening of the distal heme pocket. Substrate binding studies showed that ebselen enhanced nonproductive l-tryptophan binding, while circular dichroism indicated that the drug reduced the helical content and protein stability of rIDO. Thiol labeling and mass spectrometry revealed that ebselen reacted with multiple cysteine residues of IDO. Removal of cysteine-bound ebselen with dithiothreitol reversed the effects of the drug on the heme environment and significantly restored enzyme activity. These findings indicate that ebselen inhibits IDO activity by reacting with the enzyme's cysteine residues that result in changes to protein conformation and active site heme, leading to an increase in the level of nonproductive substrate binding. This study highlights that modification of cysteine residues is a novel and effective means of inhibiting IDO activity. It also suggests that IDO is under redox control and that the enzyme represents a previously unrecognized in vivo target of ebselen.

  17. SARS-coronavirus spike S2 domain flanked by cysteine residues C822 and C833 is important for activation of membrane fusion

    International Nuclear Information System (INIS)

    Madu, Ikenna G.; Belouzard, Sandrine; Whittaker, Gary R.

    2009-01-01

    The S2 domain of the coronavirus spike (S) protein is known to be responsible for mediating membrane fusion. In addition to a well-recognized cleavage site at the S1-S2 boundary, a second proteolytic cleavage site has been identified in the severe acute respiratory syndrome coronavirus (SARS-CoV) S2 domain (R797). C-terminal to this S2 cleavage site is a conserved region flanked by cysteine residues C822 and C833. Here, we investigated the importance of this well conserved region for SARS-CoV S-mediated fusion activation. We show that the residues between C822-C833 are well conserved across all coronaviruses. Mutagenic analysis of SARS-CoV S, combined with cell-cell fusion and pseudotyped virion infectivity assays, showed a critical role for the core-conserved residues C822, D830, L831, and C833. Based on available predictive models, we propose that the conserved domain flanked by cysteines 822 and 833 forms a loop structure that interacts with components of the SARS-CoV S trimer to control the activation of membrane fusion.

  18. Role of a cysteine residue in the active site of ERK and the MAPKK family

    International Nuclear Information System (INIS)

    Ohori, Makoto; Kinoshita, Takayoshi; Yoshimura, Seiji; Warizaya, Masaichi; Nakajima, Hidenori; Miyake, Hiroshi

    2007-01-01

    Kinases of mitogen-activated protein kinase (MAPK) cascades, including extracellular signal-regulated protein kinase (ERK), represent likely targets for pharmacological intervention in proliferative diseases. Here, we report that FR148083 inhibits ERK2 enzyme activity and TGFβ-induced AP-1-dependent luciferase expression with respective IC 50 values of 0.08 and 0.05 μM. FR265083 (1'-2' dihydro form) and FR263574 (1'-2' and 7'-8' tetrahydro form) exhibited 5.5-fold less and no activity, respectively, indicating that both the α,β-unsaturated ketone and the conformation of the lactone ring contribute to this inhibitory activity. The X-ray crystal structure of the ERK2/FR148083 complex revealed that the compound binds to the ATP binding site of ERK2, involving a covalent bond to Sγ of ERK2 Cys166, hydrogen bonds with the backbone NH of Met108, Nζ of Lys114, backbone C=O of Ser153, Nδ2 of Asn154, and hydrophobic interactions with the side chains of Ile31, Val39, Ala52, and Leu156. The covalent bond motif in the ERK2/FR148083 complex assures that the inhibitor has high activity for ERK2 and no activity for other MAPKs such as JNK1 and p38MAPKα/β/γ/δ which have leucine residues at the site corresponding to Cys166 in ERK2. On the other hand, MEK1 and MKK7, kinases of the MAPKK family which also can be inhibited by FR148083, contain a cysteine residue corresponding to Cys166 of ERK2. The covalent binding to the common cysteine residue in the ATP-binding site is therefore likely to play a crucial role in the inhibitory activity for these MAP kinases. These findings on the molecular recognition mechanisms of FR148083 for kinases with Cys166 should provide a novel strategy for the pharmacological intervention of MAPK cascades

  19. Mutational analysis of Sep-tRNA:Cys-tRNA synthase reveals critical residues for tRNA-dependent cysteine formation.

    Science.gov (United States)

    Helgadóttir, Sunna; Sinapah, Sylvie; Söll, Dieter; Ling, Jiqiang

    2012-01-02

    In methanogenic archaea, Sep-tRNA:Cys-tRNA synthase (SepCysS) converts Sep-tRNA(Cys) to Cys-tRNA(Cys). The mechanism of tRNA-dependent cysteine formation remains unclear due to the lack of functional studies. In this work, we mutated 19 conserved residues in Methanocaldococcus jannaschii SepCysS, and employed an in vivo system to determine the activity of the resulting variants. Our results show that three active-site cysteines (Cys39, Cys42 and Cys247) are essential for SepCysS activity. In addition, combined with structural modeling, our mutational and functional analyses also reveal multiple residues that are important for the binding of PLP, Sep and tRNA. Our work thus represents the first systematic functional analysis of conserved residues in archaeal SepCysSs, providing insights into the catalytic and substrate binding mechanisms of this poorly characterized enzyme. Copyright © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  20. Ligand binding and antigenic properties of a human neonatal Fc receptor with mutation of two unpaired cysteine residues

    DEFF Research Database (Denmark)

    Andersen, Jan T; Justesen, Sune; Fleckenstein, Burkhard

    2008-01-01

    knowledge gives incentives for the design of IgG and albumin-based diagnostics and therapeutics. To study FcRn in vitro and to select and characterize FcRn binders, large quantities of soluble human FcRn are needed. In this report, we explored the impact of two free cysteine residues (C48 and C251......) of the FcRn heavy chain on the overall structure and function of soluble human FcRn and described an improved bacterial production strategy based on removal of these residues, yielding approximately 70 mg.L(-1) of fermentation of refolded soluble human FcRn. The structural and functional integrity...... was proved by CD, surface plasmon resonance and MALDI-TOF peptide mapping analyses. The strategy may generally be translated to the large-scale production of other major histocompatibility complex class I-related molecules with nonfunctional unpaired cysteine residues. Furthermore, the anti-FcRn response...

  1. Direct determination of the redox status of cysteine residues in proteins in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Satoshi [Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-ku, Yokohama 226-8503 (Japan); Tatenaka, Yuki; Ohuchi, Yuya [Dojindo Laboratories, 2025-5 Tabaru, Mashiki-machi, Kumamoto 861-2202 (Japan); Hisabori, Toru, E-mail: thisabor@res.titech.ac.jp [Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-ku, Yokohama 226-8503 (Japan); Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo 102-0075 (Japan)

    2015-01-02

    Highlights: • A new DNA-maleimide which is cleaved by UV irradiation, DNA-PCMal, was developed. • DNA-PCMal can be used like DNA-Mal to analyze the redox state of cysteine residues. • It is useful for detecting the thiol redox status of a protein in vivo by Western blotting method. • Thus, DNA-PCMal can be a powerful tool for redox proteomics analysis. - Abstract: The redox states of proteins in cells are key factors in many cellular processes. To determine the redox status of cysteinyl thiol groups in proteins in vivo, we developed a new maleimide reagent, a photocleavable maleimide-conjugated single stranded DNA (DNA-PCMal). The DNA moiety of DNA-PCMal is easily removed by UV-irradiation, allowing DNA-PCMal to be used in Western blotting applications. Thereby the state of thiol groups in intracellular proteins can be directly evaluated. This new maleimide compound can provide information concerning redox proteins in vivo, which is important for our understanding of redox networks in the cell.

  2. Role of cysteine residues in the carboxyl-terminus of the follicle-stimulating hormone receptor in intracellular traffic and postendocytic processing

    Directory of Open Access Journals (Sweden)

    Brenda Melo-Nava

    2016-07-01

    Full Text Available Posttranslational modifications occurring during the biosynthesis of G protein-coupled receptors include glycosylation and palmitoylation at conserved cysteine residues located in the carboxyl-terminus (Ctail of the receptor. In a number of these receptors, these modifications play an important role in receptor function and particularly, in intracellular trafficking. In the present study, the three cysteine residues present in the carboxyl-terminus of the human FSHR were replaced with glycine by site-directed mutagenesis. Wild-type and mutant (Cys627/629/655Gly FSHRs were then transiently expressed in HEK-293 cells and analyzed for cell-surface plasma membrane expression, agonist-stimulated signaling and internalization, and postendocytic processing in the abscence and presence of lysosome and/or proteasome inhibitors. Compared with the wild-type FSHR, the triple mutant FSHR exhibited ~70% reduction in plasma membrane expression as well as a profound attenuation in agonist-stimulated cAMP production and ERK1/2 phosphorylation. Incubation of HEK-293 cells expressing the wild-type FSHR with 2-bromopalmitate (palmitoylation inhibitor for 6 h, decreased plasma membrane expression of the receptor by ~30%. The internalization kinetics and β-arrestin 1 and 2 recruitment were similar between the wild-type and triple mutant FSHR as disclosed by assays performed in non-equilibrium binding conditions and by confocal microscopy. Cells expressing the mutant FSHR recycled the internalized FSHR back to the plasma membrane less efficiently than those expressing the wild-type FSHR, an effect that was counteracted by proteasome but not by lysosome inhibition. These results indicate that replacement of the cysteine residues present in the carboxyl-terminus of the FSHR, impairs receptor trafficking from the endoplasmic reticulum/Golgi apparatus to the plasma membrane and its recycling from endosomes back to the cell surface following agonist

  3. Mutation of adjacent cysteine residues in the NSs protein of Rift Valley fever virus results in loss of virulence in mice.

    Science.gov (United States)

    Monteiro, Gaby E R; Jansen van Vuren, Petrus; Wichgers Schreur, Paul J; Odendaal, Lieza; Clift, Sarah J; Kortekaas, Jeroen; Paweska, Janusz T

    2018-04-02

    The NSs protein encoded by the S segment of Rift Valley fever virus (RVFV) is the major virulence factor, counteracting the host innate antiviral defence. It contains five highly conserved cysteine residues at positions 39, 40, 149, 178 and 194, which are thought to stabilize the tertiary and quaternary structure of the protein. Here, we report significant differences between clinical, virological, histopathological and host gene responses in BALB/c mice infected with wild-type RVFV (wtRVFV) or a genetic mutant having a double cysteine-to-serine substitution at residues 39 and 40 of the NSs protein (RVFV-C39S/C40S). Mice infected with the wtRVFV developed a fatal acute disease; characterized by high levels of viral replication, severe hepatocellular necrosis, and massive up-regulation of transcription of genes encoding type I and -II interferons (IFN) as well as pro-apoptotic and pro-inflammatory cytokines. The RVFV-C39S/C40S mutant did not cause clinical disease and its attenuated virulence was consistent with virological, histopathological and host gene expression findings in BALB/c mice. Clinical signs in mice infected with viruses containing cysteine-to-serine substitutions at positions 178 or 194 were similar to those occurring in mice infected with the wtRVFV, while a mutant containing a substitution at position 149 caused mild, non-fatal disease in mice. As mutant RVFV-C39S/C40S showed an attenuated phenotype in mice, the molecular mechanisms behind this attenuation were further investigated. The results show that two mechanisms are responsible for the attenuation; (1) loss of the IFN antagonistic propriety characteristic of the wtRVFV NSs and (2) the inability of the attenuated mutant to degrade Proteine Kinase R (PKR). Copyright © 2018. Published by Elsevier B.V.

  4. Covalent protein modification with ISG15 via a conserved cysteine in the hinge region.

    Directory of Open Access Journals (Sweden)

    Veronika N Bade

    Full Text Available The ubiquitin-like protein ISG15 (interferon-stimulated gene of 15 kDa is strongly induced by type I interferons and displays antiviral activity. As other ubiquitin-like proteins (Ubls, ISG15 is post-translationally conjugated to substrate proteins by an isopeptide bond between the C-terminal glycine of ISG15 and the side chains of lysine residues in the substrates (ISGylation. ISG15 consists of two ubiquitin-like domains that are separated by a hinge region. In many orthologs, this region contains a single highly reactive cysteine residue. Several hundred potential substrates for ISGylation have been identified but only a few of them have been rigorously verified. In order to investigate the modification of several ISG15 substrates, we have purified ISG15 conjugates from cell extracts by metal-chelate affinity purification and immunoprecipitations. We found that the levels of proteins modified by human ISG15 can be decreased by the addition of reducing agents. With the help of thiol blocking reagents, a mutational analysis and miRNA mediated knock-down of ISG15 expression, we revealed that this modification occurs in living cells via a disulphide bridge between the substrates and Cys78 in the hinge region of ISG15. While the ISG15 activating enzyme UBE1L is conjugated by ISG15 in the classical way, we show that the ubiquitin conjugating enzyme Ubc13 can either be classically conjugated by ISG15 or can form a disulphide bridge with ISG15 at the active site cysteine 87. The latter modification would interfere with its function as ubiquitin conjugating enzyme. However, we found no evidence for an ISG15 modification of the dynamin-like GTPases MxA and hGBP1. These findings indicate that the analysis of potential substrates for ISG15 conjugation must be performed with great care to distinguish between the two types of modification since many assays such as immunoprecipitation or metal-chelate affinity purification are performed with little or no

  5. Dipeptide frequency/bias analysis identifies conserved sites of nonrandomness shared by cysteine-rich motifs.

    Science.gov (United States)

    Campion, S R; Ameen, A S; Lai, L; King, J M; Munzenmaier, T N

    2001-08-15

    This report describes the application of a simple computational tool, AAPAIR.TAB, for the systematic analysis of the cysteine-rich EGF, Sushi, and Laminin motif/sequence families at the two-amino acid level. Automated dipeptide frequency/bias analysis detects preferences in the distribution of amino acids in established protein families, by determining which "ordered dipeptides" occur most frequently in comprehensive motif-specific sequence data sets. Graphic display of the dipeptide frequency/bias data revealed family-specific preferences for certain dipeptides, but more importantly detected a shared preference for employment of the ordered dipeptides Gly-Tyr (GY) and Gly-Phe (GF) in all three protein families. The dipeptide Asn-Gly (NG) also exhibited high-frequency and bias in the EGF and Sushi motif families, whereas Asn-Thr (NT) was distinguished in the Laminin family. Evaluation of the distribution of dipeptides identified by frequency/bias analysis subsequently revealed the highly restricted localization of the G(F/Y) and N(G/T) sequence elements at two separate sites of extreme conservation in the consensus sequence of all three sequence families. The similar employment of the high-frequency/bias dipeptides in three distinct protein sequence families was further correlated with the concurrence of these shared molecular determinants at similar positions within the distinctive scaffolds of three structurally divergent, but similarly employed, motif modules.

  6. Cysteine as a non toxic corrosion inhibitor for copper alloys in conservation

    DEFF Research Database (Denmark)

    Gravgaard, Mari; van Lanschot, Jettie

    2012-01-01

    studies of colour changes in the corrosion products. The results obtained in this article demonstrate that cysteine could be a non-toxic alternative to BTA. Cysteine performed as well as BTA on pre-corroded coupons with bronze disease in high humidity and showed acceptable results during testing...

  7. 5,5'-Dithiobis-(2-nitrobenzoic acid) as a probe for a non-essential cysteine residue at the medium chain acyl-coenzyme A dehydrogenase binding site of the human 'electron transferring flavoprotein' (ETF).

    Science.gov (United States)

    Parker, A; Engel, P C

    1999-01-01

    Human 'electron transferring flavoprotein' (ETF) was inactivated by the thiol-specific reagent 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB). The kinetic profile showed the reaction followed pseudo-first-order kinetics during the initial phase of inactivation. Monitoring the release of 5-thio-2-nitrobenzoate (TNB) showed that modification of 1 cysteine residue was responsible for the loss of activity. The inactivation of ETF by DTNB could be reversed upon incubation with thiol-containing reagents. The loss of activity was prevented by the inclusion of medium chain acyl-CoA dehydrogenase (MCAD) and octanoyl-CoA. Cyanolysis of the DTNB modified-ETF with KCN led to the release of TNB accompanied presumably by the formation of the thio-cyano enzyme and with almost full recovery of activity. Conservation studies and the lack of 100% inactivation, however, suggested that this cysteine residue is not essential for the interaction with MCAD.

  8. The metalloid arsenite induces nuclear export of Id3 possibly via binding to the N-terminal cysteine residues

    International Nuclear Information System (INIS)

    Kurooka, Hisanori; Sugai, Manabu; Mori, Kentaro; Yokota, Yoshifumi

    2013-01-01

    Highlights: •Sodium arsenite induces cytoplasmic accumulation of Id3. •Arsenite binds to closely spaced N-terminal cysteine residues of Id3. •N-terminal cysteines are essential for arsenite-induced nuclear export of Id3. •Nuclear export of Id3 counteracts its transcriptional repression activity. -- Abstract: Ids are versatile transcriptional repressors that regulate cell proliferation and differentiation, and appropriate subcellular localization of the Id proteins is important for their functions. We previously identified distinct functional nuclear export signals (NESs) in Id1 and Id2, but no active NES has been reported in Id3. In this study, we found that treatment with the stress-inducing metalloid arsenite led to the accumulation of GFP-tagged Id3 in the cytoplasm. Cytoplasmic accumulation was impaired by a mutation in the Id3 NES-like sequence resembling the Id1 NES, located at the end of the HLH domain. It was also blocked by co-treatment with the CRM1-specific nuclear export inhibitor leptomycin B (LMB), but not with the inhibitors for mitogen-activated protein kinases (MAPKs). Importantly, we showed that the closely spaced N-terminal cysteine residues of Id3 interacted with the arsenic derivative phenylarsine oxide (PAO) and were essential for the arsenite-induced cytoplasmic accumulation, suggesting that arsenite induces the CRM1-dependent nuclear export of Id3 via binding to the N-terminal cysteines. Finally, we demonstrated that Id3 significantly repressed arsenite-stimulated transcription of the immediate-early gene Egr-1 and that this repression activity was inversely correlated with the arsenite-induced nuclear export. Our results imply that Id3 may be involved in the biological action of arsenite

  9. Combining specificity determining and conserved residues improves functional site prediction

    Directory of Open Access Journals (Sweden)

    Gelfand Mikhail S

    2009-06-01

    Full Text Available Abstract Background Predicting the location of functionally important sites from protein sequence and/or structure is a long-standing problem in computational biology. Most current approaches make use of sequence conservation, assuming that amino acid residues conserved within a protein family are most likely to be functionally important. Most often these approaches do not consider many residues that act to define specific sub-functions within a family, or they make no distinction between residues important for function and those more relevant for maintaining structure (e.g. in the hydrophobic core. Many protein families bind and/or act on a variety of ligands, meaning that conserved residues often only bind a common ligand sub-structure or perform general catalytic activities. Results Here we present a novel method for functional site prediction based on identification of conserved positions, as well as those responsible for determining ligand specificity. We define Specificity-Determining Positions (SDPs, as those occupied by conserved residues within sub-groups of proteins in a family having a common specificity, but differ between groups, and are thus likely to account for specific recognition events. We benchmark the approach on enzyme families of known 3D structure with bound substrates, and find that in nearly all families residues predicted by SDPsite are in contact with the bound substrate, and that the addition of SDPs significantly improves functional site prediction accuracy. We apply SDPsite to various families of proteins containing known three-dimensional structures, but lacking clear functional annotations, and discusse several illustrative examples. Conclusion The results suggest a better means to predict functional details for the thousands of protein structures determined prior to a clear understanding of molecular function.

  10. Evidence for a Proton Transfer Network and a Required Persulfide-Bond-Forming Cysteine Residue in Ni-Containing Carbon Monoxide Dehydrogenases

    International Nuclear Information System (INIS)

    Eun Jin Kim; Jian Feng; Bramlett, Matthew R.; Lindahl, Paul A.

    2004-01-01

    OAK-B135 Carbon monoxide dehydrogenase from Moorella thermoacetica catalyzes the reversible oxidation of CO to CO2 at a nickel-iron-sulfur active-site called the C-cluster. Mutants of a proposed proton transfer pathway and of a cysteine residue recently found to form a persulfide bond with the C-cluster were characterized. Four semi-conserved histidine residues were individually mutated to alanine. His116 and His122 were essential to catalysis, while His113 and His119 attenuated catalysis but were not essential. Significant activity was ''rescued'' by a double mutant where His116 was replaced by Ala and His was also introduced at position 115. Activity was also rescued in double mutants where His122 was replaced by Ala and His was simultaneously introduced at either position 121 or 123. Activity was also ''rescued'' by replacing His with Cys at position 116. Mutation of conserved Lys587 near the C-cluster attenuated activity but did not eliminate it. Activity was virtually abolished in a double mutant where Lys587 and His113 were both changed to Ala. Mutations of conserved Asn284 also attenuated activity. These effects suggest the presence of a network of amino acid residues responsible for proton transfer rather than a single linear pathway. The Ser mutant of the persulfide-forming Cys316 was essentially inactive and displayed no EPR signals originating from the C-cluster. Electronic absorption and metal analysis suggests that the C-cluster is absent in this mutant. The persulfide bond appears to be essential for either the assembly or stability of the C-cluster, and/or for eliciting the redox chemistry of the C-cluster required for catalytic activity

  11. Single residue mutation in active site of serine acetyltransferase isoform 3 from Entamoeba histolytica assists in partial regaining of feedback inhibition by cysteine.

    Directory of Open Access Journals (Sweden)

    Sudhir Kumar

    Full Text Available The cysteine biosynthetic pathway is essential for survival of the protist pathogen Entamoeba histolytica, and functions by producing cysteine for countering oxidative attack during infection in human hosts. Serine acetyltransferase (SAT and O-acetylserine sulfhydrylase (OASS are involved in cysteine biosynthesis and are present in three isoforms each. While EhSAT1 and EhSAT2 are feedback inhibited by end product cysteine, EhSAT3 is nearly insensitive to such inhibition. The active site residues of EhSAT1 and of EhSAT3 are identical except for position 208, which is a histidine residue in EhSAT1 and a serine residue in EhSAT3. A combination of comparative modeling, multiple molecular dynamics simulations and free energy calculation studies showed a difference in binding energies of native EhSAT3 and of a S208H-EhSAT3 mutant for cysteine. Mutants have also been generated in vitro, replacing serine with histidine at position 208 in EhSAT3 and replacing histidine 208 with serine in EhSAT1. These mutants showed decreased affinity for substrate serine, as indicated by K(m, compared to the native enzymes. Inhibition kinetics in the presence of physiological concentrations of serine show that IC50 of EhSAT1 increases by about 18 folds from 9.59 µM for native to 169.88 µM for H208S-EhSAT1 mutant. Similar measurements with EhSAT3 confirm it to be insensitive to cysteine inhibition while its mutant (S208H-EhSAT3 shows a gain of cysteine inhibition by 36% and the IC50 of 3.5 mM. Histidine 208 appears to be one of the important residues that distinguish the serine substrate from the cysteine inhibitor.

  12. Cysteine residues mediate high‐affinity binding of thioredoxin to ASK1

    Czech Academy of Sciences Publication Activity Database

    Kylarová, Salome; Košek, Dalibor; Petrvalská, Olivia; Pšenáková, Katarína; Man, Petr; Večeř, J.; Herman, P.; Obšilová, Veronika; Obšil, Tomáš

    2016-01-01

    Roč. 283, č. 20 (2016), s. 3821-3838 ISSN 1742-464X R&D Projects: GA ČR(CZ) GA14-10061S; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 ; RVO:61388971 Keywords : ASK 1 * cysteine * disulfide bond * mass spectrometry * TRX Subject RIV: CE - Biochemistry; EE - Microbiology, Virology (MBU-M) Impact factor: 3.902, year: 2016

  13. Oxidation mimicking substitution of conservative cysteine in recoverin suppresses its membrane association.

    Science.gov (United States)

    Permyakov, Sergei E; Zernii, Evgeni Yu; Knyazeva, Ekaterina L; Denesyuk, Alexander I; Nazipova, Aliya A; Kolpakova, Tatiana V; Zinchenko, Dmitry V; Philippov, Pavel P; Permyakov, Eugene A; Senin, Ivan I

    2012-04-01

    Recoverin belongs to the family of intracellular Ca(2+)-binding proteins containing EF-hand domains, neuronal calcium sensors (NCS). In photoreceptor outer segments, recoverin is involved into the recovery of visual cycle via Ca(2+)-dependent interaction with disk membranes and inhibition of rhodopsin kinase. The function of a conservative within NCS family Cys residue in the inactive EF-loop 1 remains unclear, but previous study has shown its vulnerability to oxidation under mild oxidizing conditions. To elucidate the influence of oxidation of the conservative Cys39 in recoverin the properties of its C39D mutant, mimicking oxidative conversion of Cys39 into sulfenic, sulfinic or sulfonic acids have been studied using intrinsic fluorescence, circular dichroism, and equilibrium centrifugation methods. The C39D substitution results in essential changes in structural, physico-chemical and physiological properties of the protein: it reduces α-helical content, decreases thermal stability and suppresses protein affinity for photoreceptor membranes. The latter effect precludes proper functioning of the Ca(2+)-myristoyl switch in recoverin. The revealed significance of oxidation state of Cys39 for maintaining the protein functional status shows that it may serve as redox sensor in vision and suggests an explanation of the available data on localization and light-dependent translocation of recoverin in rod photoreceptors.

  14. Residual distribution for general time-dependent conservation laws

    International Nuclear Information System (INIS)

    Ricchiuto, Mario; Csik, Arpad; Deconinck, Herman

    2005-01-01

    We consider the second-order accurate numerical solution of general time-dependent hyperbolic conservation laws over unstructured grids in the framework of the Residual Distribution method. In order to achieve full conservation of the linear, monotone and first-order space-time schemes of (Csik et al., 2003) and (Abgrall et al., 2000), we extend the conservative residual distribution (CRD) formulation of (Csik et al., 2002) to prismatic space-time elements. We then study the design of second-order accurate and monotone schemes via the nonlinear mapping of the local residuals of linear monotone schemes. We derive sufficient and necessary conditions for the well-posedness of the mapping. We prove that the schemes obtained with the CRD formulation satisfy these conditions by construction. Thus the nonlinear schemes proposed in this paper are always well defined. The performance of the linear and nonlinear schemes are evaluated on a series of test problems involving the solution of the Euler equations and of a two-phase flow model. We consider the resolution of strong shocks and complex interacting flow structures. The results demonstrate the robustness, accuracy and non-oscillatory character of the proposed schemes. d schemes

  15. Identification of a highly conserved domain in the EcoRII methyltransferase which can be photolabeled with S-adenosyl-L-[methyl-3H]methionine. Evidence for UV-induced transmethylation of cysteine 186

    International Nuclear Information System (INIS)

    Som, S.; Friedman, S.

    1991-01-01

    DNA methyltransferases can be photolabeled with S-adenosyl-L-methionine (AdoMet). Specific incorporation of radioactivity has been demonstrated after photolabeling with either [methyl-3H]AdoMet or [35S]AdoMet. The labeling is believed to occur at the AdoMet binding site. With the purpose of localizing the site responsible for [methyl-3H]AdoMet photolabeling, we cleaved the labeled EcoRII methyltransferase by chemical and enzymatic reactions and isolated the radiolabeled peptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and high pressure liquid chromatography. The labeled peptides were identified by amino-terminal sequencing. A common region was localized which accounted for 65-70% of the total label. This region includes a highly conserved core sequence present in all DNA (cytosine 5)-methyltransferases. One such fragment was digested further with chymotrypsin, and amino acid analysis of the resulting 3H-labeled peptide was consistent with the sequence Ala-Gly-Phe-Pro-(Cys)-Gln-Pro-Phe-Ser-Leu. However, the cysteine residue was not recovered as carboxymethylcysteine. The Pro-Cys bond was found to be protected from cleavage at cysteine residues after cyanylation. These results suggest that the cysteine residue is modified by the labeling reaction. The chymotryptic fragment was hydrolyzed enzymatically to single amino acids, and the labeled amino acid was identified as S-methylcysteine by thin layer chromatography. These results indicate that the cysteine residue is located at or close to the AdoMet binding site of EcoRII methyltransferase

  16. E2-EPF UCP Possesses E3 Ubiquitin Ligase Activity via Its Cysteine 118 Residue.

    Science.gov (United States)

    Lim, Jung Hwa; Shin, Hee Won; Chung, Kyung-Sook; Kim, Nam-Soon; Kim, Ju Hee; Jung, Hong-Ryul; Im, Dong-Soo; Jung, Cho-Rok

    Here, we show that E2-EPF ubiquitin carrier protein (UCP) elongated E3-independent polyubiquitin chains on the lysine residues of von Hippel-Lindau protein (pVHL) and its own lysine residues both in vitro and in vivo. The initiation of the ubiquitin reaction depended on not only Lys11 linkage but also the Lys6, Lys48 and Lys63 residues of ubiquitin, which were involved in polyubiquitin chain formation on UCP itself. UCP self-association occurred through the UBC domain, which also contributed to the interaction with pVHL. The polyubiquitin chains appeared on the N-terminus of UCP in vivo, which indicated that the N-terminus of UCP contains target lysines for polyubiquitination. The Lys76 residue of UCP was the most critical site for auto-ubiquitination, whereas the polyubiquitin chain formation on pVHL occurred on all three of its lysines (Lys159, Lys171 and Lys196). A UCP mutant in which Cys118 was changed to alanine (UCPC118A) did not form a polyubiquitin chain but did strongly accumulate mono- and di-ubiquitin via auto-ubiquitination. Polyubiquitin chain formation required the coordination of Cys95 and Cys118 between two interacting molecules. The mechanism of the polyubiquitin chain reaction of UCP may involve the transfer of ubiquitin from Cys95 to Cys118 by trans-thiolation, with polyubiquitin chains forming at Cys118 by reversible thioester bonding. The polyubiquitin chains are then moved to the lysine residues of the substrate by irreversible isopeptide bonding. During the elongation of the ubiquitin chain, an active Cys118 residue is required in both parts of UCP, namely, the catalytic enzyme and the substrate. In conclusion, UCP possesses not only E2 ubiquitin conjugating enzyme activity but also E3 ubiquitin ligase activity, and Cys118 is critical for polyubiquitin chain formation.

  17. E2-EPF UCP Possesses E3 Ubiquitin Ligase Activity via Its Cysteine 118 Residue.

    Directory of Open Access Journals (Sweden)

    Jung Hwa Lim

    Full Text Available Here, we show that E2-EPF ubiquitin carrier protein (UCP elongated E3-independent polyubiquitin chains on the lysine residues of von Hippel-Lindau protein (pVHL and its own lysine residues both in vitro and in vivo. The initiation of the ubiquitin reaction depended on not only Lys11 linkage but also the Lys6, Lys48 and Lys63 residues of ubiquitin, which were involved in polyubiquitin chain formation on UCP itself. UCP self-association occurred through the UBC domain, which also contributed to the interaction with pVHL. The polyubiquitin chains appeared on the N-terminus of UCP in vivo, which indicated that the N-terminus of UCP contains target lysines for polyubiquitination. The Lys76 residue of UCP was the most critical site for auto-ubiquitination, whereas the polyubiquitin chain formation on pVHL occurred on all three of its lysines (Lys159, Lys171 and Lys196. A UCP mutant in which Cys118 was changed to alanine (UCPC118A did not form a polyubiquitin chain but did strongly accumulate mono- and di-ubiquitin via auto-ubiquitination. Polyubiquitin chain formation required the coordination of Cys95 and Cys118 between two interacting molecules. The mechanism of the polyubiquitin chain reaction of UCP may involve the transfer of ubiquitin from Cys95 to Cys118 by trans-thiolation, with polyubiquitin chains forming at Cys118 by reversible thioester bonding. The polyubiquitin chains are then moved to the lysine residues of the substrate by irreversible isopeptide bonding. During the elongation of the ubiquitin chain, an active Cys118 residue is required in both parts of UCP, namely, the catalytic enzyme and the substrate. In conclusion, UCP possesses not only E2 ubiquitin conjugating enzyme activity but also E3 ubiquitin ligase activity, and Cys118 is critical for polyubiquitin chain formation.

  18. Relationships between residue Voronoi volume and sequence conservation in proteins.

    Science.gov (United States)

    Liu, Jen-Wei; Cheng, Chih-Wen; Lin, Yu-Feng; Chen, Shao-Yu; Hwang, Jenn-Kang; Yen, Shih-Chung

    2018-02-01

    Functional and biophysical constraints can cause different levels of sequence conservation in proteins. Previously, structural properties, e.g., relative solvent accessibility (RSA) and packing density of the weighted contact number (WCN), have been found to be related to protein sequence conservation (CS). The Voronoi volume has recently been recognized as a new structural property of the local protein structural environment reflecting CS. However, for surface residues, it is sensitive to water molecules surrounding the protein structure. Herein, we present a simple structural determinant termed the relative space of Voronoi volume (RSV); it uses the Voronoi volume and the van der Waals volume of particular residues to quantify the local structural environment. RSV (range, 0-1) is defined as (Voronoi volume-van der Waals volume)/Voronoi volume of the target residue. The concept of RSV describes the extent of available space for every protein residue. RSV and Voronoi profiles with and without water molecules (RSVw, RSV, VOw, and VO) were compared for 554 non-homologous proteins. RSV (without water) showed better Pearson's correlations with CS than did RSVw, VO, or VOw values. The mean correlation coefficient between RSV and CS was 0.51, which is comparable to the correlation between RSA and CS (0.49) and that between WCN and CS (0.56). RSV is a robust structural descriptor with and without water molecules and can quantitatively reflect evolutionary information in a single protein structure. Therefore, it may represent a practical structural determinant to study protein sequence, structure, and function relationships. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Highly conserved small subunit residues influence rubisco large subunit catalysis.

    Science.gov (United States)

    Genkov, Todor; Spreitzer, Robert J

    2009-10-30

    The chloroplast enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step of photosynthetic CO(2) fixation. With a deeper understanding of its structure-function relationships and competitive inhibition by O(2), it may be possible to engineer an increase in agricultural productivity and renewable energy. The chloroplast-encoded large subunits form the active site, but the nuclear-encoded small subunits can also influence catalytic efficiency and CO(2)/O(2) specificity. To further define the role of the small subunit in Rubisco function, the 10 most conserved residues in all small subunits were substituted with alanine by transformation of a Chlamydomonas reinhardtii mutant that lacks the small subunit gene family. All the mutant strains were able to grow photosynthetically, indicating that none of the residues is essential for function. Three of the substitutions have little or no effect (S16A, P19A, and E92A), one primarily affects holoenzyme stability (L18A), and the remainder affect catalysis with or without some level of associated structural instability (Y32A, E43A, W73A, L78A, P79A, and F81A). Y32A and E43A cause decreases in CO(2)/O(2) specificity. Based on the x-ray crystal structure of Chlamydomonas Rubisco, all but one (Glu-92) of the conserved residues are in contact with large subunits and cluster near the amino- or carboxyl-terminal ends of large subunit alpha-helix 8, which is a structural element of the alpha/beta-barrel active site. Small subunit residues Glu-43 and Trp-73 identify a possible structural connection between active site alpha-helix 8 and the highly variable small subunit loop between beta-strands A and B, which can also influence Rubisco CO(2)/O(2) specificity.

  20. Inactivation of human DGAT2 by oxidative stress on cysteine residues

    Science.gov (United States)

    Choi, Kwangman; Kwon, Eun Bin; Kang, Mingu; Kim, Dong-eun; Jeong, Hyejeong; Kim, Janghwan; Kim, Jong Heon; Kim, Mun Ock; Han, Sang-Bae

    2017-01-01

    Diacylglycerol acyltransferases (DGATs) have a crucial role in the biosynthesis of triacylglycerol (TG), the major storage form of metabolic energy in eukaryotic organisms. Even though DGAT2, one of two distinct DGATs, has a vital role in TG biosynthesis, little is known about the regulation of DGAT2 activity. In this study, we examined the role of cysteine and its oxidation in the enzymatic activity of human DGAT2 in vitro. Human DGAT2 activity was considerably inhibited not only by thiol-modifying reagents (NEM and IA) but also by ROS-related chemicals (H2O2 and β-lapachone), while human DGAT1 and GPAT1 were little affected. Particularly, ROS-related chemicals concomitantly induced intermolecular disulfide crosslinking of human DGAT2. Both the oxidative inactivation and disulfide crosslinking were almost completely reversed by the treatment with DTT, a disulfide-reducing agent. These results clearly demonstrated the significant role of ROS-induced intermolecular crosslinking in the inactivation of human DGAT2 and also suggested DGAT2 as a redox-sensitive regulator in TG biosynthesis. PMID:28700690

  1. The iron uptake repressor Fep1 in the fission yeast binds Fe-S cluster through conserved cysteines

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo-Jin; Lee, Kang-Lok; Kim, Kyoung-Dong; Roe, Jung-Hye, E-mail: jhroe@snu.ac.kr

    2016-09-09

    Iron homeostasis is tightly regulated since iron is an essential but toxic element in the cell. The GATA-type transcription factor Fep1 and its orthologs contribute to iron homeostasis in many fungi by repressing genes for iron uptake when intracellular iron is high. Even though the function and interaction partners of Fep1 have been elucidated extensively In Schizosaccharomyces pombe, the mechanism behind iron-sensing by Fep1 remains elusive. It has been reported that Fep1 interacts with Fe-S-containing monothiol glutaredoxin Grx4 and Grx4-Fra2 complex. In this study, we demonstrate that Fep1 also binds iron, in the form of Fe-S cluster. Spectroscopic and biochemical analyses of as isolated and reconstituted Fep1 suggest that the dimeric Fep1 binds Fe-S clusters. The mutation study revealed that the cluster-binding depended on the conserved cysteines located between the two zinc fingers in the DNA binding domain. EPR analyses revealed [Fe-S]-specific peaks indicative of mixed presence of [2Fe-2S], [3Fe-4S], or [4Fe-4S]. The finding that Fep1 is an Fe-S protein fits nicely with the model that the Fe-S-trafficking Grx4 senses intracellular iron environment and modulates the activity of Fep1. - Highlights: • Fep1, a prototype fungal iron uptake regulator, was isolated stably from Schizosaccharomyces pombe. • Fep1 exhibits UV–visible absorption spectrum, characteristic of [Fe-S] proteins. • The iron and sulfide contents in purified or reconstituted Fep1 also support [Fe-S]. • The conserved cysteines are critical for [Fe-S]-binding. • EPR spectra at 5 K and 123 K suggest a mixed population of [Fe-S].

  2. The haloarchaeal MCM proteins: bioinformatic analysis and targeted mutagenesis of the β7-β8 and β9-β10 hairpin loops and conserved zinc binding domain cysteines.

    Science.gov (United States)

    Kristensen, Tatjana P; Maria Cherian, Reeja; Gray, Fiona C; MacNeill, Stuart A

    2014-01-01

    The hexameric MCM complex is the catalytic core of the replicative helicase in eukaryotic and archaeal cells. Here we describe the first in vivo analysis of archaeal MCM protein structure and function relationships using the genetically tractable haloarchaeon Haloferax volcanii as a model system. Hfx. volcanii encodes a single MCM protein that is part of the previously identified core group of haloarchaeal MCM proteins. Three structural features of the N-terminal domain of the Hfx. volcanii MCM protein were targeted for mutagenesis: the β7-β8 and β9-β10 β-hairpin loops and putative zinc binding domain. Five strains carrying single point mutations in the β7-β8 β-hairpin loop were constructed, none of which displayed impaired cell growth under normal conditions or when treated with the DNA damaging agent mitomycin C. However, short sequence deletions within the β7-β8 β-hairpin were not tolerated and neither was replacement of the highly conserved residue glutamate 187 with alanine. Six strains carrying paired alanine substitutions within the β9-β10 β-hairpin loop were constructed, leading to the conclusion that no individual amino acid within that hairpin loop is absolutely required for MCM function, although one of the mutant strains displays greatly enhanced sensitivity to mitomycin C. Deletions of two or four amino acids from the β9-β10 β-hairpin were tolerated but mutants carrying larger deletions were inviable. Similarly, it was not possible to construct mutants in which any of the conserved zinc binding cysteines was replaced with alanine, underlining the likely importance of zinc binding for MCM function. The results of these studies demonstrate the feasibility of using Hfx. volcanii as a model system for reverse genetic analysis of archaeal MCM protein function and provide important confirmation of the in vivo importance of conserved structural features identified by previous bioinformatic, biochemical and structural studies.

  3. The haloarchaeal MCM proteins: bioinformatic analysis and targeted mutagenesis of the β7-β8 and β9-β10 hairpin loops and conserved zinc binding domain cysteines

    Directory of Open Access Journals (Sweden)

    Tatjana P Kristensen

    2014-03-01

    Full Text Available The hexameric MCM complex is the catalytic core of the replicative helicase in eukaryotic and archaeal cells. Here we describe the first in vivo analysis of archaeal MCM protein structure and function relationships using the genetically tractable haloarchaeon Haloferax volcanii as a model system. Hfx. volcanii encodes a single MCM protein that is part of the previously identified core group of haloarchaeal MCM proteins. Three structural features of the N-terminal domain of the Hfx. volcanii MCM protein were targeted for mutagenesis: the β7-β8 and β9-β10 β-hairpin loops and putative zinc binding domain. Five strains carrying single point mutations in the β7-β8 β-hairpin loop were constructed, none of which displayed impaired cell growth under normal conditions or when treated with the DNA damaging agent mitomycin C. However, short sequence deletions within the β7-β8 β-hairpin were not tolerated and neither was replacement of the highly conserved residue glutamate 187 with alanine. Six strains carrying paired alanine substitutions within the β9-β10 β-hairpin loop were constructed, leading to the conclusion that no individual amino acid within that hairpin loop is absolutely required for MCM function, although one of the mutant strains displays greatly enhanced sensitivity to mitomycin C. Deletions of two or four amino acids from the β9-β10 β-hairpin were tolerated but mutants carrying larger deletions were inviable. Similarly, it was not possible to construct mutants in which any of the conserved zinc binding cysteines was replaced with alanine, underlining the likely importance of zinc binding for MCM function. The results of these studies demonstrate the feasibility of using Hfx. volcanii as a model system for reverse genetic analysis of archaeal MCM protein function and provide important confirmation of the in vivo importance of conserved structural features identified by previous bioinformatic, biochemical and structural

  4. Sulfhydryl oxidation of mutants with cysteine in place of acidic residues in the lactose permease.

    Science.gov (United States)

    Voss, J; Sun, J; Venkatesan, P; Kaback, H R

    1998-06-02

    To examine further the role of charge-pair interactions in the structure and function of lactose permease, Asp237 (helix VII), Asp240 (helix VII), Glu126 (cytoplasmic loop IV/V), Glu269 (helix VIII), and Glu325 (helix X) were replaced individually with Cys in a functional mutant devoid of Cys residues. Each mutant was then oxidized with H2O2 in order to generate a sulfinic and/or sulfonic acid at these positions. Due to the isosteric relationship between aspartate and sulfinate, in particular, and the lower pKa of the sulfinic and sulfonic acid side chains, oxidized derivatives of Cys are useful probes for examining the role of carboxylates. Asp237-->Cys or Asp240-->Cys permease is inactive, as shown previously, but H2O2 oxidation restores activity to an extent similar to that observed when a negative charge is reintroduced by other means. Glu126-->Cys, Glu269-->Cys, or Glu325-->Cys permease is inactive, but oxidation does not restore active lactose transport. The data are consistent with previous observations indicating that Asp237 and Asp240 are not critical for active lactose transport, while Glu126, Glu269, and Glu325 are irreplaceable. Although Glu269-->Cys permease does not transport lactose, the oxidized mutant exhibits significant transport of beta,D-galactosylpyranosyl 1-thio-beta,D-galactopyranoside, a property observed with Glu269-->Asp permease. The observation supports the idea that an acidic residue at position 269 is important for substrate recognition. Finally, oxidized Glu325-->Cys permease catalyzes equilibrium exchange with an apparent pKa of about 6.5, more than a pH unit lower than that observed with Glu325-->Asp permease, thereby providing strong confirmatory evidence that a negative charge at position 325 determines the rate of translocation of the ternary complex between the permease, substrate, and H+.

  5. Residue Modification and Mass Spectrometry for the Investigation of Structural and Metalation Properties of Metallothionein and Cysteine-Rich Proteins

    Directory of Open Access Journals (Sweden)

    Gordon W. Irvine

    2017-04-01

    Full Text Available Structural information regarding metallothioneins (MTs has been hard to come by due to its highly dynamic nature in the absence of metal-thiolate cluster formation and crystallization difficulties. Thus, typical spectroscopic methods for structural determination are limited in their usefulness when applied to MTs. Mass spectrometric methods have revolutionized our understanding of protein dynamics, structure, and folding. Recently, advances have been made in residue modification mass spectrometry in order to probe the hard-to-characterize structure of apo- and partially metalated MTs. By using different cysteine specific alkylation reagents, time dependent electrospray ionization mass spectrometry (ESI-MS, and step-wise “snapshot” ESI-MS, we are beginning to understand the dynamics of the conformers of apo-MT and related species. In this review we highlight recent papers that use these and similar techniques for structure elucidation and attempt to explain in a concise manner the data interpretations of these complex methods. We expect increasing resolution in our picture of the structural conformations of metal-free MTs as these techniques are more widely adopted and combined with other promising tools for structural elucidation.

  6. Palmitoylation of the Cysteine Residue in the DHHC Motif of a Palmitoyl Transferase Mediates Ca2+ Homeostasis in Aspergillus.

    Directory of Open Access Journals (Sweden)

    Yuanwei Zhang

    2016-04-01

    Full Text Available Finely tuned changes in cytosolic free calcium ([Ca2+]c mediate numerous intracellular functions resulting in the activation or inactivation of a series of target proteins. Palmitoylation is a reversible post-translational modification involved in membrane protein trafficking between membranes and in their functional modulation. However, studies on the relationship between palmitoylation and calcium signaling have been limited. Here, we demonstrate that the yeast palmitoyl transferase ScAkr1p homolog, AkrA in Aspergillus nidulans, regulates [Ca2+]c homeostasis. Deletion of akrA showed marked defects in hyphal growth and conidiation under low calcium conditions which were similar to the effects of deleting components of the high-affinity calcium uptake system (HACS. The [Ca2+]c dynamics in living cells expressing the calcium reporter aequorin in different akrA mutant backgrounds were defective in their [Ca2+]c responses to high extracellular Ca2+ stress or drugs that cause ER or plasma membrane stress. All of these effects on the [Ca2+]c responses mediated by AkrA were closely associated with the cysteine residue of the AkrA DHHC motif, which is required for palmitoylation by AkrA. Using the acyl-biotin exchange chemistry assay combined with proteomic mass spectrometry, we identified protein substrates palmitoylated by AkrA including two new putative P-type ATPases (Pmc1 and Spf1 homologs, a putative proton V-type proton ATPase (Vma5 homolog and three putative proteins in A. nidulans, the transcripts of which have previously been shown to be induced by extracellular calcium stress in a CrzA-dependent manner. Thus, our findings provide strong evidence that the AkrA protein regulates [Ca2+]c homeostasis by palmitoylating these protein candidates and give new insights the role of palmitoylation in the regulation of calcium-mediated responses to extracellular, ER or plasma membrane stress.

  7. A conserved cysteine motif is critical for rice ceramide kinase activity and function.

    Directory of Open Access Journals (Sweden)

    Fang-Cheng Bi

    Full Text Available Ceramide kinase (CERK is a key regulator of cell survival in dicotyledonous plants and animals. Much less is known about the roles of CERK and ceramides in mediating cellular processes in monocot plants. Here, we report the characterization of a ceramide kinase, OsCERK, from rice (Oryza sativa spp. Japonica cv. Nipponbare and investigate the effects of ceramides on rice cell viability.OsCERK can complement the Arabidopsis CERK mutant acd5. Recombinant OsCERK has ceramide kinase activity with Michaelis-Menten kinetics and optimal activity at 7.0 pH and 40°C. Mg2+ activates OsCERK in a concentration-dependent manner. Importantly, a CXXXCXXC motif, conserved in all ceramide kinases and important for the activity of the human enzyme, is critical for OsCERK enzyme activity and in planta function. In a rice protoplast system, inhibition of CERK leads to cell death and the ratio of added ceramide and ceramide-1-phosphate, CERK's substrate and product, respectively, influences cell survival. Ceramide-induced rice cell death has apoptotic features and is an active process that requires both de novo protein synthesis and phosphorylation, respectively. Finally, mitochondria membrane potential loss previously associated with ceramide-induced cell death in Arabidopsis was also found in rice, but it occurred with different timing.OsCERK is a bona fide ceramide kinase with a functionally and evolutionarily conserved Cys-rich motif that plays an important role in modulating cell fate in plants. The vital function of the conserved motif in both human and rice CERKs suggests that the biochemical mechanism of CERKs is similar in animals and plants. Furthermore, ceramides induce cell death with similar features in monocot and dicot plants.

  8. Subtype-selective regulation of IP(3) receptors by thimerosal via cysteine residues within the IP(3)-binding core and suppressor domain.

    Science.gov (United States)

    Khan, Samir A; Rossi, Ana M; Riley, Andrew M; Potter, Barry V L; Taylor, Colin W

    2013-04-15

    IP(3)R (IP(3) [inositol 1,4,5-trisphosphate] receptors) and ryanodine receptors are the most widely expressed intracellular Ca(2+) channels and both are regulated by thiol reagents. In DT40 cells stably expressing single subtypes of mammalian IP(3)R, low concentrations of thimerosal (also known as thiomersal), which oxidizes thiols to form a thiomercurylethyl complex, increased the sensitivity of IP(3)-evoked Ca(2+) release via IP(3)R1 and IP(3)R2, but inhibited IP(3)R3. Activation of IP(3)R is initiated by IP(3) binding to the IBC (IP(3)-binding core; residues 224-604) and proceeds via re-arrangement of an interface between the IBC and SD (suppressor domain; residues 1-223). Thimerosal (100 μM) stimulated IP(3) binding to the isolated NT (N-terminal; residues 1-604) of IP(3)R1 and IP(3)R2, but not to that of IP(3)R3. Binding of a competitive antagonist (heparin) or partial agonist (dimeric-IP(3)) to NT1 was unaffected by thiomersal, suggesting that the effect of thimerosal is specifically related to IP(3)R activation. IP(3) binding to NT1 in which all cysteine residues were replaced by alanine was insensitive to thimerosal, so too were NT1 in which cysteine residues were replaced in either the SD or IBC. This demonstrates that thimerosal interacts directly with cysteine in both the SD and IBC. Chimaeric proteins in which the SD of the IP(3)R was replaced by the structurally related A domain of a ryanodine receptor were functional, but thimerosal inhibited both IP(3) binding to the chimaeric NT and IP(3)-evoked Ca(2+) release from the chimaeric IP(3)R. This is the first systematic analysis of the effects of a thiol reagent on each IP(3)R subtype. We conclude that thimerosal selectively sensitizes IP(3)R1 and IP(3)R2 to IP(3) by modifying cysteine residues within both the SD and IBC and thereby stabilizing an active conformation of the receptor.

  9. Subtype-selective regulation of IP3 receptors by thimerosal via cysteine residues within the IP3-binding core and suppressor domain

    Science.gov (United States)

    Khan, Samir A.; Rossi, Ana M.; Riley, Andrew M.; Potter, Barry V. L.; Taylor, Colin W.

    2013-01-01

    IP3R (IP3 [inositol 1,4,5-trisphosphate] receptors) and ryanodine receptors are the most widely expressed intracellular Ca2+ channels and both are regulated by thiol reagents. In DT40 cells stably expressing single subtypes of mammalian IP3R, low concentrations of thimerosal (also known as thiomersal), which oxidizes thiols to form a thiomercurylethyl complex, increased the sensitivity of IP3-evoked Ca2+ release via IP3R1 and IP3R2, but inhibited IP3R3. Activation of IP3R is initiated by IP3 binding to the IBC (IP3-binding core; residues 224–604) and proceeds via re-arrangement of an interface between the IBC and SD (suppressor domain; residues 1–223). Thimerosal (100 μM) stimulated IP3 binding to the isolated NT (N-terminal; residues 1–604) of IP3R1 and IP3R2, but not to that of IP3R3. Binding of a competitive antagonist (heparin) or partial agonist (dimeric-IP3) to NT1 was unaffected by thiomersal, suggesting that the effect of thimerosal is specifically related to IP3R activation. IP3 binding to NT1 in which all cysteine residues were replaced by alanine was insensitive to thimerosal, so too were NT1 in which cysteine residues were replaced in either the SD or IBC. This demonstrates that thimerosal interacts directly with cysteine in both the SD and IBC. Chimaeric proteins in which the SD of the IP3R was replaced by the structurally related A domain of a ryanodine receptor were functional, but thimerosal inhibited both IP3 binding to the chimaeric NT and IP3-evoked Ca2+ release from the chimaeric IP3R. This is the first systematic analysis of the effects of a thiol reagent on each IP3R subtype. We conclude that thimerosal selectively sensitizes IP3R1 and IP3R2 to IP3 by modifying cysteine residues within both the SD and IBC and thereby stabilizing an active conformation of the receptor. PMID:23282150

  10. Replication of murine coronavirus requires multiple cysteines in the endodomain of spike protein

    International Nuclear Information System (INIS)

    Yang, Jinhua; Lv, Jun; Wang, Yuyan; Gao, Shuang; Yao, Qianqian; Qu, Di; Ye, Rong

    2012-01-01

    A conserved cysteine-rich motif located between the transmembrane domain and the endodomain is essential for membrane fusion and assembly of coronavirus spike (S) protein. Here, we proved that three cysteines within the motif, but not dependent on position, are minimally required for the survival of the recombinant mouse hepatitis virus. When the carboxy termini with these mutated motifs of S proteins were respectively introduced into a heterogeneous protein, both incorporation into lipid rafts and S-palmitoylation of these recombinant proteins showed a similar quantity requirement to cysteine residues. Meanwhile, the redistribution of these proteins on cellular surface indicated that the absence of the positively charged rather than cysteine residues in the motif might lead the dramatic reduction in syncytial formation of some mutants with the deleted motifs. These results suggest that multiple cysteine as well as charged residues concurrently improves the membrane-associated functions of S protein in viral replication and cytopathogenesis.

  11. Replication of murine coronavirus requires multiple cysteines in the endodomain of spike protein

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jinhua; Lv, Jun; Wang, Yuyan; Gao, Shuang; Yao, Qianqian; Qu, Di; Ye, Rong, E-mail: yerong24@fudan.edu.cn

    2012-06-05

    A conserved cysteine-rich motif located between the transmembrane domain and the endodomain is essential for membrane fusion and assembly of coronavirus spike (S) protein. Here, we proved that three cysteines within the motif, but not dependent on position, are minimally required for the survival of the recombinant mouse hepatitis virus. When the carboxy termini with these mutated motifs of S proteins were respectively introduced into a heterogeneous protein, both incorporation into lipid rafts and S-palmitoylation of these recombinant proteins showed a similar quantity requirement to cysteine residues. Meanwhile, the redistribution of these proteins on cellular surface indicated that the absence of the positively charged rather than cysteine residues in the motif might lead the dramatic reduction in syncytial formation of some mutants with the deleted motifs. These results suggest that multiple cysteine as well as charged residues concurrently improves the membrane-associated functions of S protein in viral replication and cytopathogenesis.

  12. Role of cysteine residues in the structure, stability, and alkane producing activity of cyanobacterial aldehyde deformylating oxygenase.

    Directory of Open Access Journals (Sweden)

    Yuuki Hayashi

    Full Text Available Aldehyde deformylating oxygenase (AD is a key enzyme for alkane biosynthesis in cyanobacteria, and it can be used as a catalyst for alkane production in vitro and in vivo. However, three free Cys residues in AD may impair its catalytic activity by undesired disulfide bond formation and oxidation. To develop Cys-deficient mutants of AD, we examined the roles of the Cys residues in the structure, stability, and alkane producing activity of AD from Nostoc punctiforme PCC 73102 by systematic Cys-to-Ala/Ser mutagenesis. The C71A/S mutations reduced the hydrocarbon producing activity of AD and facilitated the formation of a dimer, indicating that the conserved Cys71, which is located in close proximity to the substrate-binding site, plays crucial roles in maintaining the activity, structure, and stability of AD. On the other hand, mutations at Cys107 and Cys117 did not affect the hydrocarbon producing activity of AD. Therefore, we propose that the C107A/C117A double mutant is preferable to wild type AD for alkane production and that the double mutant may be used as a pseudo-wild type protein for further improvement of the alkane producing activity of AD.

  13. On the relationship between residue structural environment and sequence conservation in proteins.

    Science.gov (United States)

    Liu, Jen-Wei; Lin, Jau-Ji; Cheng, Chih-Wen; Lin, Yu-Feng; Hwang, Jenn-Kang; Huang, Tsun-Tsao

    2017-09-01

    Residues that are crucial to protein function or structure are usually evolutionarily conserved. To identify the important residues in protein, sequence conservation is estimated, and current methods rely upon the unbiased collection of homologous sequences. Surprisingly, our previous studies have shown that the sequence conservation is closely correlated with the weighted contact number (WCN), a measure of packing density for residue's structural environment, calculated only based on the C α positions of a protein structure. Moreover, studies have shown that sequence conservation is correlated with environment-related structural properties calculated based on different protein substructures, such as a protein's all atoms, backbone atoms, side-chain atoms, or side-chain centroid. To know whether the C α atomic positions are adequate to show the relationship between residue environment and sequence conservation or not, here we compared C α atoms with other substructures in their contributions to the sequence conservation. Our results show that C α positions are substantially equivalent to the other substructures in calculations of various measures of residue environment. As a result, the overlapping contributions between C α atoms and the other substructures are high, yielding similar structure-conservation relationship. Take the WCN as an example, the average overlapping contribution to sequence conservation is 87% between C α and all-atom substructures. These results indicate that only C α atoms of a protein structure could reflect sequence conservation at the residue level. © 2017 Wiley Periodicals, Inc.

  14. Ranking multiple docking solutions based on the conservation of inter-residue contacts

    KAUST Repository

    Oliva, Romina M.; Vangone, Anna; Cavallo, Luigi

    2013-01-01

    ) conformations in the top positions is still an open problem. Herein we present CONSRANK, a simple and effective tool to rank multiple docking solutions, which relies on the conservation of inter-residue contacts in the analyzed decoys ensemble. First

  15. Modification by covalent reaction or oxidation of cysteine residues in the tandem-SH2 domains of ZAP-70 and Syk can block phosphopeptide binding.

    Science.gov (United States)

    Visperas, Patrick R; Winger, Jonathan A; Horton, Timothy M; Shah, Neel H; Aum, Diane J; Tao, Alyssa; Barros, Tiago; Yan, Qingrong; Wilson, Christopher G; Arkin, Michelle R; Weiss, Arthur; Kuriyan, John

    2015-01-01

    Zeta-chain associated protein of 70 kDa (ZAP-70) and spleen tyrosine kinase (Syk) are non-receptor tyrosine kinases that are essential for T-cell and B-cell antigen receptor signalling respectively. They are recruited, via their tandem-SH2 (Src-homology domain 2) domains, to doubly phosphorylated immunoreceptor tyrosine-based activation motifs (ITAMs) on invariant chains of immune antigen receptors. Because of their critical roles in immune signalling, ZAP-70 and Syk are targets for the development of drugs for autoimmune diseases. We show that three thiol-reactive small molecules can prevent the tandem-SH2 domains of ZAP-70 and Syk from binding to phosphorylated ITAMs. We identify a specific cysteine residue in the phosphotyrosine-binding pocket of each protein (Cys39 in ZAP-70, Cys206 in Syk) that is necessary for inhibition by two of these compounds. We also find that ITAM binding to ZAP-70 and Syk is sensitive to the presence of H2O2 and these two cysteine residues are also necessary for inhibition by H2O2. Our findings suggest a mechanism by which the reactive oxygen species generated during responses to antigen could attenuate signalling through these kinases and may also inform the development of ZAP-70 and Syk inhibitors that bind covalently to their SH2 domains.

  16. Reverse Conservation Analysis Reveals the Specificity Determining Residues of Cytochrome P450 Family 2 (CYP 2

    Directory of Open Access Journals (Sweden)

    Tai-Sung Lee

    2008-01-01

    Full Text Available The concept of conservation of amino acids is widely used to identify important alignment positions of orthologs. The assumption is that important amino acid residues will be conserved in the protein family during the evolutionary process. For paralog alignment, on the other hand, the opposite concept can be used to identify residues that are responsible for specificity. Assuming that the function-specific or ligand-specific residue positions will have higher diversity since they are under evolutionary pressure to fit the target specificity, these function-specific or ligand-specific residues positions will have a lower degree of conservation than other positions in a highly conserved paralog alignment. This study assessed the ability of reverse conservation analysis to identify function-specific and ligand-specific residue positions in closely related paralog. Reverse conservation analysis of paralog alignments successfully identified all six previously reported substrate recognition sites (SRSs in cytochrome P450 family 2 (CYP 2. Further analysis of each subfamily identified the specificity-determining residues (SDRs that have been experimentally found. New potential SDRs were also predicted and await confirmation by further experiments or modeling calculations. This concept may be also applied to identify SDRs in other protein families.

  17. Bacteria binding by DMBT1/SAG/gp-340 is confined to the VEVLXXXXW motif in its scavenger receptor cysteine-rich domains

    DEFF Research Database (Denmark)

    Bikker, Floris J; Ligtenberg, Antoon J M; End, Caroline

    2004-01-01

    The scavenger receptor cysteine-rich (SRCR) proteins form an archaic group of metazoan proteins characterized by the presence of SRCR domains. These proteins are classified in group A and B based on the number of conserved cysteine residues in their SRCR domains, i.e. six for group A and eight fo...

  18. Cysteine residues 244 and 458–459 within the catalytic subunit of Na,K-ATPase control the enzyme's hydrolytic and signaling function under hypoxic conditions

    Directory of Open Access Journals (Sweden)

    Irina Yu. Petrushanko

    2017-10-01

    Full Text Available Our previous findings suggested that reversible thiol modifications of cysteine residues within the actuator (AD and nucleotide binding domain (NBD of the Na,K-ATPase may represent a powerful regulatory mechanism conveying redox- and oxygen-sensitivity of this multifunctional enzyme. S-glutathionylation of Cys244 in the AD and Cys 454-458-459 in the NBD inhibited the enzyme and protected cysteines’ thiol groups from irreversible oxidation under hypoxic conditions. In this study mutagenesis approach was used to assess the role these cysteines play in regulation of the Na,K-ATPase hydrolytic and signaling functions. Several constructs of mouse α1 subunit of the Na,K-ATPase were produced in which Cys244, Cys 454-458-459 or Cys 244-454-458-459 were replaced by alanine. These constructs were expressed in human HEK293 cells. Non-transfected cells and those expressing murine α1 subunit were exposed to hypoxia or treated with oxidized glutathione (GSSG. Both conditions induced inhibition of the wild type Na,K-ATPase. Enzymes containing mutated mouse α1 lacking Cys244 or all four cysteines (Cys 244-454-458-459 were insensitive to hypoxia. Inhibitory effect of GSSG was observed for wild type murine Na,K-ATPase, but was less pronounced in Cys454-458-459Ala mutant and completely absent in the Cys244Ala and Cys 244-454-458-459Ala mutants. In cells, expressing wild type enzyme, ouabain induced activation of Src and Erk kinases under normoxic conditions, whereas under hypoxic conditions this effect was inversed. Cys454-458-459Ala substitution abolished Src kinase activation in response to ouabain treatment, uncoupled Src from Erk signaling, and interfered with O2-sensitivity of Na,K-ATPase signaling function. Moreover, modeling predicted that S-glutathionylation of Cys 458 and 459 should prevent inhibitory binding of Src to NBD. Our data indicate for the first time that cysteine residues within the AD and NBD influence hydrolytic as well as receptor

  19. Trypanoplasma borreli cysteine proteinase activities support a conservation of function with respect to digestion of host proteins in common carp

    NARCIS (Netherlands)

    Ruszczyk, Aleksandra; Forlenza, Maria; Joerink, Maaike; Ribeiro, Carla M. S.; Jurecka, Patrycja; Wiegertjes, Geert F.

    2008-01-01

    Trypanoplasma borreli is an extracellular parasite that is transmitted by a leech vector and is naturally found in the blood of cyprinid fish. High parasitemia and associated severe anemia together with splenomegaly are typical of infection of common carp, Cyprinus carpio L. Papain-like cysteine

  20. Trypanoplasma borreli cystein proteinase activities support a conservation of function with respect to digestion of host proteins in common carp

    NARCIS (Netherlands)

    Ruszczyk, A.; Forlenza, M.; Joerink, M.; Ribeiro, C.M.S.; Jurecka, P.M.; Wiegertjes, G.F.

    2008-01-01

    Trypanoplasma borreli is an extracellular parasite that is transmitted by a leech vector and is naturally found in the blood of cyprinid fish. High parasitemia and associated severe anemia together with splenomegaly are typical of infection of common carp, Cyprinus carpio L. Papain-like cysteine

  1. Profiling of proteolytic enzymes in the gut of the tick Ixodes ricinus reveals an evolutionarily conserved network of aspartic and cysteine peptidases

    Directory of Open Access Journals (Sweden)

    Mareš Michael

    2008-03-01

    Full Text Available Abstract Background Ticks are vectors for a variety of viral, bacterial and parasitic diseases in human and domestic animals. To survive and reproduce ticks feed on host blood, yet our understanding of the intestinal proteolytic machinery used to derive absorbable nutrients from the blood meal is poor. Intestinal digestive processes are limiting factors for pathogen transmission since the tick gut presents the primary site of infection. Moreover, digestive enzymes may find practical application as anti-tick vaccine targets. Results Using the hard tick, Ixodes ricinus, we performed a functional activity scan of the peptidase complement in gut tissue extracts that demonstrated the presence of five types of peptidases of the cysteine and aspartic classes. We followed up with genetic screens of gut-derived cDNA to identify and clone genes encoding the cysteine peptidases cathepsins B, L and C, an asparaginyl endopeptidase (legumain, and the aspartic peptidase, cathepsin D. By RT-PCR, expression of asparaginyl endopeptidase and cathepsins B and D was restricted to gut tissue and to those developmental stages feeding on blood. Conclusion Overall, our results demonstrate the presence of a network of cysteine and aspartic peptidases that conceivably operates to digest host blood proteins in a concerted manner. Significantly, the peptidase components of this digestive network are orthologous to those described in other parasites, including nematodes and flatworms. Accordingly, the present data and those available for other tick species support the notion of an evolutionary conservation of a cysteine/aspartic peptidase system for digestion that includes ticks, but differs from that of insects relying on serine peptidases.

  2. The myeloperoxidase-derived oxidant hypothiocyanous acid inhibits protein tyrosine phosphatases via oxidation of key cysteine residues

    DEFF Research Database (Denmark)

    Cook, Naomi L.; Moeke, Cassidy H.; Fantoni, Luca I.

    2016-01-01

    Phosphorylation of protein tyrosine residues is critical to cellular processes, and is regulated by kinases and phosphatases (PTPs). PTPs contain a redox-sensitive active site Cys residue, which is readily oxidized. Myeloperoxidase, released from activated leukocytes, catalyzes thiocyanate ion (SCN...

  3. Herpes Simplex Virus Type 1 Glycoprotein B Requires a Cysteine Residue at Position 633 for Folding, Processing, and Incorporation into Mature Infectious Virus Particles

    Science.gov (United States)

    Laquerre, Sylvie; Anderson, Dina B.; Argnani, Rafaela; Glorioso, Joseph C.

    1998-01-01

    Herpes simplex virus type 1 (HSV-1) glycoprotein B (gB) resides in the virus envelope in an oligomeric form and plays an essential role in virus entry into susceptible host cells. The oligomerizing domain is a movable element consisting of amino acids 626 to 653 in the gB external domain. This domain contains a single cysteine residue at position 633 (Cys-633) that is predicted to form an intramolecular disulfide bridge with Cys-596. In this study, we examined gB oligomerization, processing, and incorporation into mature virus during infection by two mutant viruses in which either the gB Cys-633 [KgB(C633S)] or both Cys-633 and Cys-596 [KgB(C596S/C633S)] residues were mutated to serine. The result of immunofluorescence studies and analyses of released virus particles showed that the mutant gB molecules were not transported to the cell surface or incorporated into mature virus envelopes and thus infectious virus was not produced. Immunoprecipitation studies revealed that the mutant gB molecules were in an oligomeric configuration and that these mutants produced hetero-oligomers with a truncated form of gB consisting of residues 1 to 43 and 595 to 904, the latter containing the oligomerization domain. Pulse-chase experiments in combination with endoglycosidase H treatment determined that the mutant molecules were improperly processed, having been retained in the endoplasmic reticulum (ER). Coimmunoprecipitation experiments revealed that the cysteine mutations resulted in gB misfolding and retention by the molecular chaperones calnexin, calreticulin, and Grp78 in the ER. The altered conformation of the gB mutant glycoproteins was directly detected by a reduction in monoclonal antibody recognition of two previously defined distinct antigenic sites located within residues 381 to 441 and 595 to 737. The misfolded molecules were not transported to the cell surface as hetero-oligomers with wild-type gB, suggesting that the conformational change could not be corrected by

  4. Against the odds? De novo structure determination of a pilin with two cysteine residues by sulfur SAD.

    Science.gov (United States)

    Gorgel, Manuela; Bøggild, Andreas; Ulstrup, Jakob Jensen; Weiss, Manfred S; Müller, Uwe; Nissen, Poul; Boesen, Thomas

    2015-05-01

    Exploiting the anomalous signal of the intrinsic S atoms to phase a protein structure is advantageous, as ideally only a single well diffracting native crystal is required. However, sulfur is a weak anomalous scatterer at the typical wavelengths used for X-ray diffraction experiments, and therefore sulfur SAD data sets need to be recorded with a high multiplicity. In this study, the structure of a small pilin protein was determined by sulfur SAD despite several obstacles such as a low anomalous signal (a theoretical Bijvoet ratio of 0.9% at a wavelength of 1.8 Å), radiation damage-induced reduction of the cysteines and a multiplicity of only 5.5. The anomalous signal was improved by merging three data sets from different volumes of a single crystal, yielding a multiplicity of 17.5, and a sodium ion was added to the substructure of anomalous scatterers. In general, all data sets were balanced around the threshold values for a successful phasing strategy. In addition, a collection of statistics on structures from the PDB that were solved by sulfur SAD are presented and compared with the data. Looking at the quality indicator R(anom)/R(p.i.m.), an inconsistency in the documentation of the anomalous R factor is noted and reported.

  5. The Influence of Repeat Surgery and Residual Disease on Recurrence After Breast-Conserving Surgery

    DEFF Research Database (Denmark)

    Bodilsen, Anne; Bjerre, Karsten; Offersen, Birgitte V

    2015-01-01

    BACKGROUND: A significant proportion of women who have breast-conserving surgery (BCS) subsequently undergo re-excision or proceed to mastectomy. This study aimed to identify factors associated with residual disease after repeat surgery and to determine their effect on ipsilateral breast tumor re...

  6. Protein Topology Determines Cysteine Oxidation Fate: The Case of Sulfenyl Amide Formation among Protein Families

    Science.gov (United States)

    Defelipe, Lucas A.; Lanzarotti, Esteban; Gauto, Diego; Marti, Marcelo A.; Turjanski, Adrián G.

    2015-01-01

    Cysteine residues have a rich chemistry and play a critical role in the catalytic activity of a plethora of enzymes. However, cysteines are susceptible to oxidation by Reactive Oxygen and Nitrogen Species, leading to a loss of their catalytic function. Therefore, cysteine oxidation is emerging as a relevant physiological regulatory mechanism. Formation of a cyclic sulfenyl amide residue at the active site of redox-regulated proteins has been proposed as a protection mechanism against irreversible oxidation as the sulfenyl amide intermediate has been identified in several proteins. However, how and why only some specific cysteine residues in particular proteins react to form this intermediate is still unknown. In the present work using in-silico based tools, we have identified a constrained conformation that accelerates sulfenyl amide formation. By means of combined MD and QM/MM calculation we show that this conformation positions the NH backbone towards the sulfenic acid and promotes the reaction to yield the sulfenyl amide intermediate, in one step with the concomitant release of a water molecule. Moreover, in a large subset of the proteins we found a conserved beta sheet-loop-helix motif, which is present across different protein folds, that is key for sulfenyl amide production as it promotes the previous formation of sulfenic acid. For catalytic activity, in several cases, proteins need the Cysteine to be in the cysteinate form, i.e. a low pKa Cys. We found that the conserved motif stabilizes the cysteinate by hydrogen bonding to several NH backbone moieties. As cysteinate is also more reactive toward ROS we propose that the sheet-loop-helix motif and the constraint conformation have been selected by evolution for proteins that need a reactive Cys protected from irreversible oxidation. Our results also highlight how fold conservation can be correlated to redox chemistry regulation of protein function. PMID:25741692

  7. Case studies in residual use and energy conservation at wastewater treatment plants

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, D. [Science Applications International Corp., Los Altos, CA (United States)

    1995-06-01

    The US Environmental Protection Agency (EPA) and the National Renewable Energy Laboratory (NREL) for the US Department of Energy (DOE) funded a study to document energy conservation activities and their effects on operation costs, regulatory compliance, and process optimization at several wastewater treatment plants (WWTPS). The purpose of this report is to review the efforts of wastewater treatment Facilities that use residuals as fuels. Case histories are presented for facilities that have taken measures to reduce energy consumption during wastewater treatment. Most of the WWTPs discussed in this report have retrofitted existing facilities to achieve energy conservation. The case studies of energy conservation measures found no effects on the facilities` ability to comply with NPDES permits. Indeed, energy conservation activities enhance environmental compliance in several ways.

  8. Conserved residues of the human mitochondrial holocytochrome c synthase mediate interactions with heme.

    Science.gov (United States)

    Babbitt, Shalon E; San Francisco, Brian; Bretsnyder, Eric C; Kranz, Robert G

    2014-08-19

    C-type cytochromes are distinguished by the covalent attachment of a heme cofactor, a modification that is typically required for its subsequent folding, stability, and function. Heme attachment takes place in the mitochondrial intermembrane space and, in most eukaryotes, is mediated by holocytochrome c synthase (HCCS). HCCS is the primary component of the eukaryotic cytochrome c biogenesis pathway, known as System III. The catalytic function of HCCS depends on its ability to coordinate interactions between its substrates: heme and cytochrome c. Recent advancements in the recombinant expression and purification of HCCS have facilitated comprehensive analyses of the roles of conserved residues in HCCS, as demonstrated in this study. Previously, we proposed a four-step model describing HCCS-mediated cytochrome c assembly, identifying a conserved histidine residue (His154) as an axial ligand to the heme iron. In this study, we performed a systematic mutational analysis of 17 conserved residues in HCCS, and we provide evidence that the enzyme contains two heme-binding domains. Our data indicate that heme contacts mediated by residues within these domains modulate the dynamics of heme binding and contribute to the stability of the HCCS-heme-cytochrome c steady state ternary complex. While some residues are essential for initial heme binding (step 1), others impact the subsequent release of the holocytochrome c product (step 4). Certain HCCS mutants that were defective in heme binding were corrected for function by exogenous aminolevulinic acid (ALA, the precursor to heme). This chemical "correction" supports the proposed role of heme binding for the corresponding residues.

  9. Residue management practices and planter attachments for corn production in a conservation agriculture system

    Directory of Open Access Journals (Sweden)

    J. Nejadi

    2013-11-01

    Full Text Available Seed placement and failure to establish a uniform plant stand are critical problems associated with production of corn (Zea mays following wheat (Triticum aestivum in a conservation agriculture system in Iran. Our objectives were to evaluate the performance of a corn row- crop planter equipped with two planter attachments (smooth/toothed coulters at six wheat residue management systems (three tillage systems and two levels of surface residue at two forward speeds of 5 and 7 km h-1. Residue retained after planting, seeding depth, emergence rate index (ERI and seed spacing indices were determined. The baled residue plots tilled by chisel plow followed by disc harrow (BRCD resulted in minimum residue after planting as compared to other residue treatments. Furthermore, the maximum values of the ERI and uniformity of plant spacing pertained to this treatment. Other results showed that the ERI increased up to 18% for the toothed coulter as compared to the smooth coulter. The toothed coulter also established a deeper seed placement as compared to the smooth coulter. Planting at forward speed of 5 km h-1 resulted in deeper seeding depth as compared to a forward speed of 7 km h-1. However, lower values of miss and precision indices were obtained at forward speed of 7 km h-1, indicating a more uniformity of plant spacing. Results of this study showed that equipping the conventional planter with toothed coulter and planting in soil prepared under the BRCD residue management system can result in a satisfactory conservation crop production system.

  10. Characterization of conserved arginine residues on Cdt1 that affect licensing activity and interaction with Geminin or Mcm complex.

    Science.gov (United States)

    You, Zhiying; Ode, Koji L; Shindo, Mayumi; Takisawa, Haruhiko; Masai, Hisao

    2016-05-02

    All organisms ensure once and only once replication during S phase through a process called replication licensing. Cdt1 is a key component and crucial loading factor of Mcm complex, which is a central component for the eukaryotic replicative helicase. In higher eukaryotes, timely inhibition of Cdt1 by Geminin is essential to prevent rereplication. Here, we address the mechanism of DNA licensing using purified Cdt1, Mcm and Geminin proteins in combination with replication in Xenopus egg extracts. We mutagenized the 223th arginine of mouse Cdt1 (mCdt1) to cysteine or serine (R-S or R-C, respectively) and 342nd and 346th arginines constituting an arginine finger-like structure to alanine (RR-AA). The RR-AA mutant of Cdt1 could not only rescue the DNA replication activity in Cdt1-depleted extracts but also its specific activity for DNA replication and licensing was significantly increased compared to the wild-type protein. In contrast, the R223 mutants were partially defective in rescue of DNA replication and licensing. Biochemical analyses of these mutant Cdt1 proteins indicated that the RR-AA mutation disabled its functional interaction with Geminin, while R223 mutations resulted in ablation in interaction with the Mcm2∼7 complex. Intriguingly, the R223 mutants are more susceptible to the phosphorylation-induced inactivation or chromatin dissociation. Our results show that conserved arginine residues play critical roles in interaction with Geminin and Mcm that are crucial for proper conformation of the complexes and its licensing activity.

  11. Three cysteine residues of SLC52A1, a receptor for the porcine endogenous retrovirus-A (PERV-A), play a critical role in cell surface expression and infectivity.

    Science.gov (United States)

    Colon-Moran, Winston; Argaw, Takele; Wilson, Carolyn A

    2017-07-01

    Porcine endogenous retrovirus-A (PERV-A), a gammaretrovirus, infects human cells in vitro, thus raising the potential risk of cross-species transmission in xenotransplantation. Two members of the solute carrier family 52 (SLC52A1 and SLC52A2) are PERV-A receptors. Site-directed mutagenesis of the cDNA encoding SLC52A1 identified that only one of two putative glycosylation signals is occupied by glycans. In addition, we showed that glycosylation of SLC52A1 is not necessary for PERV-A receptor function. We also identified that at a minimum, three cysteine residues are sufficient for SLC52A1 cell surface expression. Mutation of cysteine at position 365 and either of the two cysteine residues in the C-terminal tail at positions 442 or 446 reduced SLC52A1 surface expression and PERV-A infection suggesting that these residues may contribute to overall structural stability and receptor function. Understanding interactions between PERV-A and its cellular receptor may provide novel strategies to prevent zoonotic infection in the setting of xenotransplantation. Published by Elsevier Inc.

  12. Optimal expression of a Fab-effector fusion protein in Escherichia coli by removing the cysteine residues responsible for an interchain disulfide bond of a Fab molecule.

    Science.gov (United States)

    Kang, Hyeon-Ju; Kim, Hye-Jin; Jung, Mun-Sik; Han, Jae-Kyu; Cha, Sang-Hoon

    2017-04-01

    Development of novel bi-functional or even tri-functional Fab-effector fusion proteins would have a great potential in the biomedical sciences. However, the expression of Fab-effector fusion proteins in Escherichia coli is problematic especially when a eukaryotic effector moiety is genetically linked to a Fab due to the lack of proper chaperone proteins and an inappropriate physicochemical environment intrinsic to the microbial hosts. We previously reported that a human Fab molecule, referred to as SL335, reactive to human serum albumin has a prolonged in vivo serum half-life in rats. We, herein, tested six discrete SL335-human growth hormone (hGH) fusion constructs as a model system to define an optimal Fab-effector fusion format for E. coli expression. We found that one variant, referred to as HserG/Lser, outperformed the others in terms of a soluble expression yield and functionality in that HserG/Lser has a functional hGH bioactivity and possesses an serum albumin-binding affinity comparable to SL335. Our results clearly demonstrated that the genetic linkage of an effector domain to the C-terminus of Fd (V H +C H1 ) and the removal of cysteine (Cys) residues responsible for an interchain disulfide bond (IDB) ina Fab molecule optimize the periplasmic expression of a Fab-effector fusion protein in E. coli. We believe that our approach can contribute the development of diverse bi-functional Fab-effector fusion proteins by providing a simple strategy that enables the reliable expression of a functional fusion proteins in E. coli. Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

  13. Mutant INS-gene induced diabetes of youth: proinsulin cysteine residues impose dominant-negative inhibition on wild-type proinsulin transport.

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2010-10-01

    Full Text Available Recently, a syndrome of Mutant INS-gene-induced Diabetes of Youth (MIDY, derived from one of 26 distinct mutations has been identified as a cause of insulin-deficient diabetes, resulting from expression of a misfolded mutant proinsulin protein in the endoplasmic reticulum (ER of insulin-producing pancreatic beta cells. Genetic deletion of one, two, or even three alleles encoding insulin in mice does not necessarily lead to diabetes. Yet MIDY patients are INS-gene heterozygotes; inheritance of even one MIDY allele, causes diabetes. Although a favored explanation for the onset of diabetes is that insurmountable ER stress and ER stress response from the mutant proinsulin causes a net loss of beta cells, in this report we present three surprising and interlinked discoveries. First, in the presence of MIDY mutants, an increased fraction of wild-type proinsulin becomes recruited into nonnative disulfide-linked protein complexes. Second, regardless of whether MIDY mutations result in the loss, or creation, of an extra unpaired cysteine within proinsulin, Cys residues in the mutant protein are nevertheless essential in causing intracellular entrapment of co-expressed wild-type proinsulin, blocking insulin production. Third, while each of the MIDY mutants induces ER stress and ER stress response; ER stress and ER stress response alone appear insufficient to account for blockade of wild-type proinsulin. While there is general agreement that ultimately, as diabetes progresses, a significant loss of beta cell mass occurs, the early events described herein precede cell death and loss of beta cell mass. We conclude that the molecular pathogenesis of MIDY is initiated by perturbation of the disulfide-coupled folding pathway of wild-type proinsulin.

  14. Using a consensus approach based on the conservation of inter-residue contacts to rank CAPRI models

    KAUST Repository

    Vangone, Anna; Cavallo, Luigi; Oliva, Romina M.

    2013-01-01

    Herein we propose the use of a consensus approach, CONSRANK, for ranking CAPRI models. CONSRANK relies on the conservation of inter-residue contacts in the analyzed decoys ensemble. Models are ranked according to their ability to match the most

  15. Disentangling evolutionary signals: conservation, specificity determining positions and coevolution. Implication for catalytic residue prediction

    DEFF Research Database (Denmark)

    Teppa, Elin; Wilkins, Angela D.; Nielsen, Morten

    2012-01-01

    Background: A large panel of methods exists that aim to identify residues with critical impact on protein function based on evolutionary signals, sequence and structure information. However, it is not clear to what extent these different methods overlap, and if any of the methods have higher...... predictive potential compared to others when it comes to, in particular, the identification of catalytic residues (CR) in proteins. Using a large set of enzymatic protein families and measures based on different evolutionary signals, we sought to break up the different components of the information content......-value Evolutionary Trace (rvET) methods and conservation, another containing mutual information (MI) methods, and the last containing methods designed explicitly for the identification of specificity determining positions (SDPs): integer-value Evolutionary Trace (ivET), SDPfox, and XDET. In terms of prediction of CR...

  16. Conserved Aromatic Residue Confers Cation Selectivity in Claudin-2 and Claudin-10b*

    Science.gov (United States)

    Li, Jiahua; Zhuo, Min; Pei, Lei; Yu, Alan S. L.

    2013-01-01

    In tight junctions, both claudin-2 and claudin-10b form paracellular cation-selective pores by the interaction of the first ECL 1 with permeating ions. We hypothesized that a highly conserved aromatic residue near the pore selectivity filter of claudins contributes to cation selectivity by cation-π interaction with the permeating cation. To test this, we generated MDCK I Tet-off cells stably transfected with claudin-2 Tyr67 mutants. The Y67L mutant showed reduced cation selectivity compared with wild-type claudin-2 due to a decrease in Na+ permeability, without affecting the Cl− permeability. The Y67A mutant enlarged the pore size and further decreased the charge selectivity due to an increase in Cl− permeability. The Y67F mutant restored the Na+ permeability, Cl− permeability, and pore size back to wild-type. The accessibility of Y67C to methanethiosulfonate modification indicated that its side chain faces the lumen of the pore. In claudin-10b, the F66L mutant reduced cation selectivity, and the F66A mutant lost pore conductance. We conclude that the conserved aromatic residue near the cation pore domain of claudins contributes to cation selectivity by a dual role of cation-π interaction and a luminal steric effect. Our findings provide new insight into how ion selectivity is achieved in the paracellular pore. PMID:23760508

  17. Residue conservation and dimer-interface analysis of olfactory receptor molecular models

    Directory of Open Access Journals (Sweden)

    Ramanathan Sowdhamini

    2012-10-01

    Full Text Available Olfactory Receptors (ORs are members of the Class A rhodopsin like G-protein coupled receptors (GPCRs which are the initial players in the signal transduction cascade, leading to the generation of nerve impulses transmitted to the brain and resulting in the detection of odorant molecules. Despite the accumulation of thousands of olfactory receptor sequences, no crystal structures of ORs are known tο date. However, the recent availability of crystallographic models of a few GPCRs allows us to generate homology models of ORs and analyze their amino acid patterns, as there is a huge diversity in OR sequences. In this study, we have generated three-dimensional models of 100 representative ORs from Homo sapiens, Mus musculus, Drosophila melanogaster, Caenorhabditis elegans and Sacharomyces cerevisiae which were selected on the basis of a composite classification scheme and phylogenetic analysis. The crystal structure of bovine rhodopsin was used as a template and it was found that the full-length models have more than 90% of their residues in allowed regions of the Ramachandran plot. The structures were further used for analysis of conserved residues in the transmembrane and extracellular loop regions in order to identify functionally important residues. Several ORs are known to be functional as dimers and hence dimer interfaces were predicted for OR models to analyse their oligomeric functional state.

  18. Identification of conserved regions and residues within Hedgehog acyltransferase critical for palmitoylation of Sonic Hedgehog.

    Directory of Open Access Journals (Sweden)

    John A Buglino

    2010-06-01

    Full Text Available Sonic hedgehog (Shh is a palmitoylated protein that plays key roles in mammalian development and human cancers. Palmitoylation of Shh is required for effective long and short range Shh-mediated signaling. Attachment of palmitate to Shh is catalyzed by Hedgehog acyltransferase (Hhat, a member of the membrane bound O-acyl transferase (MBOAT family of multipass membrane proteins. The extremely hydrophobic composition of MBOAT proteins has limited their biochemical characterization. Except for mutagenesis of two conserved residues, there has been no structure-function analysis of Hhat, and the regions of the protein required for Shh palmitoylation are unknown.Here we undertake a systematic approach to identify residues within Hhat that are required for protein stability and/or enzymatic activity. We also identify a second, novel MBOAT homology region (residues 196-234 that is required for Hhat activity. In total, ten deletion mutants and eleven point mutants were generated and analyzed. Truncations at the N- and C-termini of Hhat yielded inactive proteins with reduced stability. Four Hhat mutants with deletions within predicted loop regions and five point mutants retained stability but lost palmitoylation activity. We purified two point mutants, W378A and H379A, with defective Hhat activity. Kinetic analyses revealed alterations in apparent K(m and V(max for Shh and/or palmitoyl CoA, changes that likely explain the catalytic defects observed for these mutants.This study has pinpointed specific regions and multiple residues that regulate Hhat stability and catalysis. Our findings should be applicable to other MBOAT proteins that mediate lipid modification of Wnt proteins and ghrelin, and should serve as a model for understanding how secreted morphogens are modified by palmitoyl acyltransferases.

  19. Bridge helix bending promotes RNA polymerase II backtracking through a critical and conserved threonine residue

    KAUST Repository

    Da, Lin-Tai

    2016-04-19

    The dynamics of the RNA polymerase II (Pol II) backtracking process is poorly understood. We built a Markov State Model from extensive molecular dynamics simulations to identify metastable intermediate states and the dynamics of backtracking at atomistic detail. Our results reveal that Pol II backtracking occurs in a stepwise mode where two intermediate states are involved. We find that the continuous bending motion of the Bridge helix (BH) serves as a critical checkpoint, using the highly conserved BH residue T831 as a sensing probe for the 3′-terminal base paring of RNA:DNA hybrid. If the base pair is mismatched, BH bending can promote the RNA 3′-end nucleotide into a frayed state that further leads to the backtracked state. These computational observations are validated by site-directed mutagenesis and transcript cleavage assays, and provide insights into the key factors that regulate the preferences of the backward translocation.

  20. Bridge helix bending promotes RNA polymerase II backtracking through a critical and conserved threonine residue

    KAUST Repository

    Da, Lin-Tai; Pardo-Avila, Fá tima; Xu, Liang; Silva, Daniel-Adriano; Zhang, Lu; Gao, Xin; Wang, Dong; Huang, Xuhui

    2016-01-01

    The dynamics of the RNA polymerase II (Pol II) backtracking process is poorly understood. We built a Markov State Model from extensive molecular dynamics simulations to identify metastable intermediate states and the dynamics of backtracking at atomistic detail. Our results reveal that Pol II backtracking occurs in a stepwise mode where two intermediate states are involved. We find that the continuous bending motion of the Bridge helix (BH) serves as a critical checkpoint, using the highly conserved BH residue T831 as a sensing probe for the 3′-terminal base paring of RNA:DNA hybrid. If the base pair is mismatched, BH bending can promote the RNA 3′-end nucleotide into a frayed state that further leads to the backtracked state. These computational observations are validated by site-directed mutagenesis and transcript cleavage assays, and provide insights into the key factors that regulate the preferences of the backward translocation.

  1. Intragenic suppressor of Osiaa23 revealed a conserved tryptophan residue crucial for protein-protein interactions.

    Directory of Open Access Journals (Sweden)

    Jun Ni

    Full Text Available The Auxin/Indole-3-Acetic Acid (Aux/IAA and Auxin Response Factor (ARF are two important families that play key roles in auxin signal transduction. Both of the families contain a similar carboxyl-terminal domain (Domain III/IV that facilitates interactions between these two families. In spite of the importance of protein-protein interactions among these transcription factors, the mechanisms involved in these interactions are largely unknown. In this study, we isolated six intragenic suppressors of an auxin insensitive mutant, Osiaa23. Among these suppressors, Osiaa23-R5 successfully rescued all the defects of the mutant. Sequence analysis revealed that an amino acid substitution occurred in the Tryptophan (W residue in Domain IV of Osiaa23. Yeast two-hybrid experiments showed that the mutation in Domain IV prevents the protein-protein interactions between Osiaa23 and OsARFs. Phylogenetic analysis revealed that the W residue is conserved in both OsIAAs and OsARFs. Next, we performed site-specific amino acid substitutions within Domain IV of OsARFs, and the conserved W in Domain IV was exchanged by Serine (S. The mutated OsARF(WSs can be released from the inhibition of Osiaa23 and maintain the transcriptional activities. Expression of OsARF(WSs in Osiaa23 mutant rescued different defects of the mutant. Our results suggest a previously unknown importance of Domain IV in both families and provide an indirect way to investigate functions of OsARFs.

  2. Ranking multiple docking solutions based on the conservation of inter-residue contacts

    KAUST Repository

    Oliva, Romina M.

    2013-06-17

    Molecular docking is the method of choice for investigating the molecular basis of recognition in a large number of functional protein complexes. However, correctly scoring the obtained docking solutions (decoys) to rank native-like (NL) conformations in the top positions is still an open problem. Herein we present CONSRANK, a simple and effective tool to rank multiple docking solutions, which relies on the conservation of inter-residue contacts in the analyzed decoys ensemble. First it calculates a conservation rate for each inter-residue contact, then it ranks decoys according to their ability to match the more frequently observed contacts. We applied CONSRANK to 102 targets from three different benchmarks, RosettaDock, DOCKGROUND, and Critical Assessment of PRedicted Interactions (CAPRI). The method performs consistently well, both in terms of NL solutions ranked in the top positions and of values of the area under the receiver operating characteristic curve. Its ideal application is to solutions coming from different docking programs and procedures, as in the case of CAPRI targets. For all the analyzed CAPRI targets where a comparison is feasible, CONSRANK outperforms the CAPRI scorers. The fraction of NL solutions in the top ten positions in the RosettaDock, DOCKGROUND, and CAPRI benchmarks is enriched on average by a factor of 3.0, 1.9, and 9.9, respectively. Interestingly, CONSRANK is also able to specifically single out the high/medium quality (HMQ) solutions from the docking decoys ensemble: it ranks 46.2 and 70.8% of the total HMQ solutions available for the RosettaDock and CAPRI targets, respectively, within the top 20 positions. © 2013 Wiley Periodicals, Inc.

  3. FragKB: structural and literature annotation resource of conserved peptide fragments and residues.

    Directory of Open Access Journals (Sweden)

    Ashish V Tendulkar

    Full Text Available BACKGROUND: FragKB (Fragment Knowledgebase is a repository of clusters of structurally similar fragments from proteins. Fragments are annotated with information at the level of sequence, structure and function, integrating biological descriptions derived from multiple existing resources and text mining. METHODOLOGY: FragKB contains approximately 400,000 conserved fragments from 4,800 representative proteins from PDB. Literature annotations are extracted from more than 1,700 articles and are available for over 12,000 fragments. The underlying systematic annotation workflow of FragKB ensures efficient update and maintenance of this database. The information in FragKB can be accessed through a web interface that facilitates sequence and structural visualization of fragments together with known literature information on the consequences of specific residue mutations and functional annotations of proteins and fragment clusters. FragKB is accessible online at http://ubio.bioinfo.cnio.es/biotools/fragkb/. SIGNIFICANCE: The information presented in FragKB can be used for modeling protein structures, for designing novel proteins and for functional characterization of related fragments. The current release is focused on functional characterization of proteins through inspection of conservation of the fragments.

  4. A case of postirradiation angiosarcoma developed in the residual breast after breast-conserving surgery

    International Nuclear Information System (INIS)

    Nomura, Shinji; Okazaki, Yoshikazu; Fujii, Masakazu; Akiyama, Norio; Tomozawa, Naofumi; Morishige, Ichiro

    2008-01-01

    The patient was a 50-year-old woman who had undergone breast-conserving surgery for right breast cancer (C area, Bp+Ax, T2N0M0, Stage I, and scirrhous carcinoma), followed by irradiation at a total dose of 50 Gy in 1998. When 6 years 5 months had elapsed after the operation, redness and induration developed in the A area of the right breast. A biopsy via wedge resection was performed and the histopathological diagnosis was angiosarcoma. We could not rule out a possibility of positive surgical stump, and performed additional resection+skin grafting. No sarcoma remnant was demonstrated in the material resected additionally, but 2 years later, the patient experienced recurrence. Thus mastectomy+extended resection of the full thickness of the skin+skin grafting were performed. Postirradiation sarcoma involving the skin and vessels is a rare entity and occurs in 0.03-0.8% of all cases after radiation therapy. It metastasizes to the distant organs in an early stage and carries poor prognosis. No standard therapy for the disease has been established as yet. Early detection and extended resection are considered to contribute to an improvement of the prognosis. This paper deals with such a rare entity as postirradiation angiosarcoma developed in the residual breast after breast-conserving surgery. (author)

  5. Functional identification of conserved residues involved in Lactobacillus rhamnosus strain GG sortase specificity and pilus biogenesis.

    Science.gov (United States)

    Douillard, François P; Rasinkangas, Pia; von Ossowski, Ingemar; Reunanen, Justus; Palva, Airi; de Vos, Willem M

    2014-05-30

    In Gram-positive bacteria, sortase-dependent pili mediate the adhesion of bacteria to host epithelial cells and play a pivotal role in colonization, host signaling, and biofilm formation. Lactobacillus rhamnosus strain GG, a well known probiotic bacterium, also displays on its cell surface mucus-binding pilus structures, along with other LPXTG surface proteins, which are processed by sortases upon specific recognition of a highly conserved LPXTG motif. Bioinformatic analysis of all predicted LPXTG proteins encoded by the L. rhamnosus GG genome revealed a remarkable conservation of glycine residues juxtaposed to the canonical LPXTG motif. Here, we investigated and defined the role of this so-called triple glycine (TG) motif in determining sortase specificity during the pilus assembly and anchoring. Mutagenesis of the TG motif resulted in a lack or an alteration of the L. rhamnosus GG pilus structures, indicating that the TG motif is critical in pilus assembly and that they govern the pilin-specific and housekeeping sortase specificity. This allowed us to propose a regulatory model of the L. rhamnosus GG pilus biogenesis. Remarkably, the TG motif was identified in multiple pilus gene clusters of other Gram-positive bacteria, suggesting that similar signaling mechanisms occur in other, mainly pathogenic, species. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Protein modification by acrolein: Formation and stability of cysteine adducts

    OpenAIRE

    Cai, Jian; Bhatnagar, Aruni; Pierce, William M.

    2009-01-01

    The toxicity of the ubiquitous pollutant and endogenous metabolite, acrolein, is due in part to covalent protein modifications. Acrolein reacts readily with protein nucleophiles via Michael addition and Schiff base formation. Potential acrolein targets in protein include the nucleophilic side chains of cysteine, histidine, and lysine residues as well as the free amino terminus of proteins. Although cysteine is the most acrolein-reactive residue, cysteine-acrolein adducts are difficult to iden...

  7. Cysteine proteinases and cystatins

    Directory of Open Access Journals (Sweden)

    Adeliana S. Oliveira

    2003-01-01

    Full Text Available This review describeds the definition, localization, functions and examples of cysteine proteinases and their protein inhibitors in vertebrate, non-vertebrate animals and plants. These inhibitors are related with defense mechanisms of plant against pests. It also describes the factors involved in the specific cysteine proteinase-cystatin interaction and high degree of affinity and large specificity in this interaction which are not only represented by the compatibility between amino acid residues of the active site involved in catalysis, but also of all amino acid residues that participante in the enzyme-inhibitor interaction.Nesta revisão foram descritas definições, localizações, funções e exemplos de proteinases cisteínicas e suas proteinas inibidoras em animais vertebrados e invertebrados e plantas. Tratamos principalmente com aqueles inibidores que são relatados com o mecanismo de defesa da planta contra pestes. Em adição, comentamos sobre recentes trabalhos que contribuíram para uma melhor compreenção dos fatores envolvidos na interação específica proteinase cisteínica-cistatina. Por outro lado, chamamos atenção para o alto grau de afinidade e grande especificidade na interação que não são apenas representadas pela compatibilidade entre os residuos de aminoácidos do sítio ativo envolvidos na catalise, mas também de todos os resíduos de aminoácidos que participam da interação enzima-inibidor.

  8. Molecular Basis for Enzymatic Sulfite Oxidation -- HOW THREE CONSERVED ACTIVE SITE RESIDUES SHAPE ENZYME ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Susan; Rapson, Trevor; Johnson-Winters, Kayunta; Astashkin, Andrei; Enemark, John; Kappler, Ulrike

    2008-11-10

    Sulfite dehydrogenases (SDHs) catalyze the oxidation and detoxification of sulfite to sulfate, a reaction critical to all forms of life. Sulfite-oxidizing enzymes contain three conserved active site amino acids (Arg-55, His-57, and Tyr-236) that are crucial for catalytic competency. Here we have studied the kinetic and structural effects of two novel and one previously reported substitution (R55M, H57A, Y236F) in these residues on SDH catalysis. Both Arg-55 and His-57 were found to have key roles in substrate binding. An R55M substitution increased Km(sulfite)(app) by 2-3 orders of magnitude, whereas His-57 was required for maintaining a high substrate affinity at low pH when the imidazole ring is fully protonated. This effect may be mediated by interactions of His-57 with Arg-55 that stabilize the position of the Arg-55 side chain or, alternatively, may reflect changes in the protonation state of sulfite. Unlike what is seen for SDHWT and SDHY236F, the catalytic turnover rates of SDHR55M and SDHH57A are relatively insensitive to pH (~;;60 and 200 s-1, respectively). On the structural level, striking kinetic effects appeared to correlate with disorder (in SDHH57A and SDHY236F) or absence of Arg-55 (SDHR55M), suggesting that Arg-55 and the hydrogen bonding interactions it engages in are crucial for substrate binding and catalysis. The structure of SDHR55M has sulfate bound at the active site, a fact that coincides with a significant increase in the inhibitory effect of sulfate in SDHR55M. Thus, Arg-55 also appears to be involved in enabling discrimination between the substrate and product in SDH.

  9. Conservation of Oxidative Protein Stabilization in an Insect Homologue of Parkinsonism-Associated Protein DJ-1

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jiusheng; Prahlad, Janani; Wilson, Mark A. (UNL)

    2012-08-21

    DJ-1 is a conserved, disease-associated protein that protects against oxidative stress and mitochondrial damage in multiple organisms. Human DJ-1 contains a functionally essential cysteine residue (Cys106) whose oxidation is important for regulating protein function by an unknown mechanism. This residue is well-conserved in other DJ-1 homologues, including two (DJ-1{alpha} and DJ-1{beta}) in Drosophila melanogaster. Because D. melanogaster is a powerful model system for studying DJ-1 function, we have determined the crystal structure and impact of cysteine oxidation on Drosophila DJ-1{beta}. The structure of D. melanogaster DJ-1{beta} is similar to that of human DJ-1, although two important residues in the human protein, Met26 and His126, are not conserved in DJ-1{beta}. His126 in human DJ-1 is substituted with a tyrosine in DJ-1{beta}, and this residue is not able to compose a putative catalytic dyad with Cys106 that was proposed to be important in the human protein. The reactive cysteine in DJ-1 is oxidized readily to the cysteine-sulfinic acid in both flies and humans, and this may regulate the cytoprotective function of the protein. We show that the oxidation of this conserved cysteine residue to its sulfinate form (Cys-SO{sub 2{sup -}}) results in considerable thermal stabilization of both Drosophila DJ-1{beta} and human DJ-1. Therefore, protein stabilization is one potential mechanism by which cysteine oxidation may regulate DJ-1 function in vivo. More generally, most close DJ-1 homologues are likely stabilized by cysteine-sulfinic acid formation but destabilized by further oxidation, suggesting that they are biphasically regulated by oxidative modification.

  10. Production of Human Cu,Zn SOD with Higher Activity and Lower Toxicity in E. coli via Mutation of Free Cysteine Residues

    Directory of Open Access Journals (Sweden)

    Kun Zhang

    2017-01-01

    Full Text Available Although, as an antioxidant enzyme, human Cu,Zn superoxide dismutase 1 (hSOD1 can mitigate damage to cell components caused by free radicals generated by aerobic metabolism, large-scale manufacturing and clinical use of hSOD1 are still limited by the challenge of rapid and inexpensive production of high-quality eukaryotic hSOD1 in recombinant forms. We have demonstrated previously that it is a promising strategy to increase the expression levels of soluble hSOD1 so as to increase hSOD1 yields in E. coli. In this study, a wild-type hSOD1 (wtSOD1 and three mutant SOD1s (mhSOD1s, in which free cysteines were substituted with serine, were constructed and their expression in soluble form was measured. Results show that the substitution of Cys111 (mhSOD1/C111S increased the expression of soluble hSOD1 in E. coli whereas substitution of the internal Cys6 (mhSOD1/C6S decreased it. Besides, raised levels of soluble expression led to an increase in hSOD1 yields. In addition, mhSOD1/C111S expressed at a higher soluble level showed lower toxicity and stronger whitening and antiradiation activities than those of wtSOD1. Taken together, our data demonstrate that C111S mutation in hSOD1 is an effective strategy to develop new SOD1-associated reagents and that mhSOD1/C111S is a satisfactory candidate for large-scale production.

  11. A highly Conserved Aspartic Acid Residue of the Chitosanase from Bacillus Sp. TS Is Involved in the Substrate Binding.

    Science.gov (United States)

    Zhou, Zhanping; Zhao, Shuangzhi; Liu, Yang; Chang, Zhengying; Ma, Yanhe; Li, Jian; Song, Jiangning

    2016-11-01

    The chitosanase from Bacillus sp. TS (CsnTS) is an enzyme belonging to the glycoside hydrolase family 8. The sequence of CsnTS shares 98 % identity with the chitosanase from Bacillus sp. K17. Crystallography analysis and site-direct mutagenesis of the chitosanase from Bacillus sp. K17 identified the important residues involved in the catalytic interaction and substrate binding. However, despite progress in understanding the catalytic mechanism of the chitosanase from the family GH8, the functional roles of some residues that are highly conserved throughout this family have not been fully elucidated. This study focused on one of these residues, i.e., the aspartic acid residue at position 318. We found that apart from asparagine, mutation of Asp318 resulted in significant loss of enzyme activity. In-depth investigations showed that mutation of this residue not only impaired enzymatic activity but also affected substrate binding. Taken together, our results showed that Asp318 plays an important role in CsnTS activity.

  12. The economics of soil conservation in developing countries: the case of crop residue mulching

    NARCIS (Netherlands)

    Erenstein, O.C.A.

    1999-01-01

    The study contributes to the search for a methodology to assess soil conservation, particularly in developing countries. The study first assesses the economics of soil conservation in general - with special emphasis on the relationships between technology, economic analysis and policy implications.

  13. The cysteine 34 residue of A1M/α1-microglobulin is essential for protection of irradiated cell cultures and reduction of carbonyl groups.

    Science.gov (United States)

    Rutardottir, S; Nilsson, E J C; Pallon, J; Gram, M; Åkerström, B

    2013-07-01

    α1-microglobulin (A1M) is a 26 kDa plasma and a tissue protein belonging to the lipocalin family. The reductase and free radical scavenger A1M has been shown to protect cells and extracellular matrix against oxidative and irradiation-induced damage. The reductase activity was previously shown to depend upon an unpaired cysteinyl side-chain, C34, and three lysyl side-chains, K92, 118, and 130, located around the open end of the lipocalin pocket. The aim of this work was to investigate whether the cell and matrix protection by A1M is a result of its reductase activity by using A1M-variants with site-directed mutations of the C34, K92, K118, and K130 positions. The results show that the C34 side-chain is an absolute requirement for protection of HepG2 cell cultures against alpha-particle irradiation-induced cell death, upregulation of stress response and cell cycle regulation genes. Mutation of C34 also resulted in loss of the reduction capacity toward heme- and hydrogen peroxide-oxidized collagen, and the radical species 2,2´-azino-bis (3-ethyl-benzo-thiazoline-6-sulphonic acid) (ABTS). Furthermore, mutation of C34 significantly suppressed the cell-uptake of A1M. The K92, K118, and K130 side-chains were of minor importance in cell protection and reduction of oxidized collagen but strongly influenced the reduction of the ABTS-radical. It is concluded that antioxidative protection of cells and collagen by A1M is totally dependent on its C34 amino acid residue. A model of the cell protection mechanism of A1M should be based on the redox activity of the free thiolyl group of the C34 side-chain and a regulatory role of the K92, K118, and K130 residues.

  14. A conserved residue cluster that governs kinetics of ATP-dependent gating of Kir6.2 potassium channels

    DEFF Research Database (Denmark)

    Zhang, Roger S; Wright, Jordan; Pless, Stephan Alexander

    2015-01-01

    modest effects on gating kinetics despite significant changes in ATP sensitivity and open probability. However, we identified a pair of highly conserved neighboring amino acids (Trp68, Lys170) that control the rate of channel opening and inhibition in response to ATP. Paradoxically, mutations of Trp68...... or Lys170 markedly slow the kinetics of channel opening (500 ms and 700 ms for Trp68Leu and Lys170Asn, respectively), while increasing channel open probability. Examining the functional effects of these residues using phi-value analysis revealed a steep negative slope. This finding implies...

  15. Reconstruction of Cysteine Biosynthesis Using Engineered Cysteine-Free and Methionine-Free Enzymes

    Science.gov (United States)

    Wang, Kendrick; Fujishima, Kosuke; Abe, Nozomi; Nakahigashi, Kenji; Endy, Drew; Rothschild, Lynn J.

    2016-01-01

    Ten of the proteinogenic amino acids can be generated abiotically while the remaining thirteen require biology for their synthesis. Paradoxically, the biosynthesis pathways observed in nature require enzymes that are made with the amino acids they produce. For example, Escherichia coli produces cysteine from serine via two enzymes that contain cysteine. Here, we substituted alternate amino acids for cysteine and also methionine, which is biosynthesized from cysteine, in serine acetyl transferase (CysE) and O-acetylserine sulfhydrylase (CysM). CysE function was rescued by cysteine-and-methionine-free enzymes and CysM function was rescued by cysteine-free enzymes. Structural modeling suggests that methionine stabilizes CysM and is present in the active site of CysM. Cysteine is not conserved among CysE and CysM protein orthologs, suggesting that cysteine is not functionally important for its own synthesis. Engineering biosynthetic enzymes that lack the amino acids being synthesized provides insights into the evolution of amino acid biosynthesis and pathways for bioengineering.

  16. Long-term impact of reduced tillage and residue management on soil carbon stabilization: Implications for conservation agriculture on contrasting soil

    NARCIS (Netherlands)

    Chivenge, P.P.; Murwira, H.K.; Giller, K.E.; Mapfumo, P.; Six, J.

    2007-01-01

    Residue retention and reduced tillage are both conservation agricultural management options that may enhance soil organic carbon (SOC) stabilization in tropical soils. Therefore, we evaluated the effects of long-term tillage and residue management on SOC dynamics in a Chromic Luvisol (red clay soil)

  17. A conserved residue of l-alanine dehydrogenase from Bacillus pseudofirmus, Lys-73, participates in the catalytic reaction through hydrogen bonding.

    Science.gov (United States)

    He, Guangzheng; Xu, Shujing; Wang, Shanshan; Zhang, Qing; Liu, Dong; Chen, Yuling; Ju, Jiansong; Zhao, Baohua

    2018-03-01

    A multiple protein sequence alignment of l-alanine dehydrogenases from different bacterial species revealed that five highly conserved amino acid residues Arg-15, Lys-73, Lys-75, His-96 and Asp-269 are potential catalytic residues of l-alanine dehydrogenase from Bacillus pseudofirmus OF4. In this study, recombinant OF4Ald and its mutants of five conserved residues were constructed, expressed in Escherichia coli, purified by His 6 -tag affinity column and gel filtration chromatography, structure homology modeling, and characterized. The purified protein OF4Ald displayed high specificity to l-alanine (15Umg -1 ) with an optimal temperature and pH of 40°C and 10.5, respectively. Enzymatic assay and activity staining in native gels showed that mutations at four conserved residue Arg-15, Lys-75, His-96 and Asp-269 (except residue Lys-73) resulted in a complete loss in enzymatic activity, which signified that these predicted active sites are indispensable for OF4Ald activity. In contrast, the mutant K73A resulted in 6-fold improvement in k cat /K m towards l-alanine as compared to the wild type protein. Further research of the residue Lys-73 substituted by various amino acids and structural modeling revealed that residue Lys-73 might be involved in the catalytic reaction of the enzyme by influencing the enzyme-substrate binding through the hydrogen-bonding interaction with conserved residue Lys-75. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Residue management increases fallow water conservation and yield deficit irrigated crops grown in rotation with wheat

    Science.gov (United States)

    No-tillage (NT) residue management provides cover to increase precipitation capture compared with disk tillage (DT) or in the absence of a cover crop. Therefore, NT has the potential to reduce irrigation withdrawals from the declining Ogallala Aquifer. In a 4-year study, we quantified DT and NT effe...

  19. Crop residue is key for sustaining maximum food production and for conservation of our biosphere

    Science.gov (United States)

    Crop residue is key in our efforts to move towards agricultural sustainability. This paper provides a quick overview of some selected references and looks at some of the newest advances related to cover crops. Several authors have described in detail the benefits derived from improving soil quality ...

  20. Identification in the mu-opioid receptor of cysteine residues responsible for inactivation of ligand binding by thiol alkylating and reducing agents.

    Science.gov (United States)

    Gaibelet, G; Capeyrou, R; Dietrich, G; Emorine, L J

    1997-05-19

    Inactivation by thiol reducing and alkylating agents of ligand binding to the human mu-opioid receptor was examined. Dithiothreitol reduced the number of [3H]diprenorphine binding sites. Replacement by seryl residues of either C142 or C219 in extracellular loops 1 and 2 of the mu receptor resulted in a complete loss of opioid binding. A disulfide bound linking C142 to C219 may thus be essential to maintain a functional conformation of the receptor. We also demonstrated that inactivation of ligand binding upon alkylation by N-ethylmaleimide occurred at two sites. Alteration of the more sensitive (IC50 = 20 microM) did not modify antagonists binding but decreased agonist affinity almost 10-fold. Modification of the less reactive site (IC50 = 2 mM) decreased the number of both agonist and antagonist binding sites. The alkylation site of higher sensitivity to N-ethylmaleimide was shown by mutagenesis experiments to be constituted of both C81 and C332 in transmembrane domains 1 and 7 of the mu-opioid receptor.

  1. Conservation

    NARCIS (Netherlands)

    Noteboom, H.P.

    1985-01-01

    The IUCN/WWF Plants Conservation Programme 1984 — 1985. World Wildlife Fund chose plants to be the subject of their fund-raising campaign in the period 1984 — 1985. The objectives were to: 1. Use information techniques to achieve the conservation objectives of the Plants Programme – to save plants;

  2. Conservation.

    Science.gov (United States)

    National Audubon Society, New York, NY.

    This set of teaching aids consists of seven Audubon Nature Bulletins, providing the teacher and student with informational reading on various topics in conservation. The bulletins have these titles: Plants as Makers of Soil, Water Pollution Control, The Ground Water Table, Conservation--To Keep This Earth Habitable, Our Threatened Air Supply,…

  3. Contributions of conserved residues at the gating interface of glycine receptors

    DEFF Research Database (Denmark)

    Pless, Stephan Alexander; Leung, Ada W Y; Galpin, Jason D

    2011-01-01

    and the in vivo nonsense suppression method to incorporate unnatural amino acids to probe the electrostatic and hydrophobic contributions of five highly conserved side chains near the interface, Glu-53, Phe-145, Asp-148, Phe-187, and Arg-218. Our results suggest a salt bridge between Asp-148 in loop 7 and Arg-218......Glycine receptors (GlyRs) are chloride channels that mediate fast inhibitory neurotransmission and are members of the pentameric ligand-gated ion channel (pLGIC) family. The interface between the ligand binding domain and the transmembrane domain of pLGICs has been proposed to be crucial...

  4. Activation of the oxidative stress regulator PpYap1 through conserved cysteine residues during methanol metabolism in the yeast Pichia pastoris.

    Science.gov (United States)

    Yano, Taisuke; Yurimoto, Hiroya; Sakai, Yasuyoshi

    2009-06-01

    The methylotrophic yeast Pichia pastoris can grow on methanol as sole source of carbon and energy. The first reaction in yeast methanol metabolism, catalyzed by an abundant peroxisomal enzyme, alcohol oxidase, generates high levels of H(2)O(2), but the oxidative stress response during methanol metabolism has not been elucidated. In this study, we isolated the Yap1 homolog of P. pastoris (PpYap1) and analyzed the properties of a PpYAP1-disruption strain. The PpYap1 transcription factor is activated after exposure to various reactive agents, and therefore functions as a regulator of the redox system in P. pastoris. We have also identified PpGPX1, the unique glutathione peroxidase-encoding gene in P. pastoris whose expression is induced by PpYap1. PpGpx1, but not the ScTsa1 or SpTpx1 homolog PpTsa1, functions as a H(2)O(2) sensor and activates PpYap1. This study is the first demonstration of a yeast Yap1 family protein activated during conventional metabolism.

  5. Analysis of the solvent accessibility of cysteine residues on Maize rayado fino virus virus-like particles produced in Nicotiana benthamiana plants and cross-linking of peptides to VLPs.

    Science.gov (United States)

    Natilla, Angela; Hammond, Rosemarie W

    2013-02-14

    Mimicking and exploiting virus properties and physicochemical and physical characteristics holds promise to provide solutions to some of the world's most pressing challenges. The sheer range and types of viruses coupled with their intriguing properties potentially give endless opportunities for applications in virus-based technologies. Viruses have the ability to self- assemble into particles with discrete shape and size, specificity of symmetry, polyvalence, and stable properties under a wide range of temperature and pH conditions. Not surprisingly, with such a remarkable range of properties, viruses are proposed for use in biomaterials, vaccines, electronic materials, chemical tools, and molecular electronic containers. In order to utilize viruses in nanotechnology, they must be modified from their natural forms to impart new functions. This challenging process can be performed through several mechanisms including genetic modification of the viral genome and chemically attaching foreign or desired molecules to the virus particle reactive groups. The ability to modify a virus primarily depends upon the physiochemical and physical properties of the virus. In addition, the genetic or physiochemical modifications need to be performed without adversely affecting the virus native structure and virus function. Maize rayado fino virus (MRFV) coat proteins self-assemble in Escherichia coli producing stable and empty VLPs that are stabilized by protein-protein interactions and that can be used in virus-based technologies applications. VLPs produced in tobacco plants were examined as a scaffold on which a variety of peptides can be covalently displayed. Here, we describe the steps to 1) determine which of the solvent-accessible cysteines in a virus capsid are available for modification, and 2) bioconjugate peptides to the modified capsids. By using native or mutationally-inserted amino acid residues and standard coupling technologies, a wide variety of materials have been

  6. The conserved Lysine69 residue plays a catalytic role in Mycobacterium tuberculosis shikimate dehydrogenase

    Directory of Open Access Journals (Sweden)

    Rodrigues Valnês

    2009-01-01

    Full Text Available Abstract Background The shikimate pathway is an attractive target for the development of antitubercular agents because it is essential in Mycobacterium tuberculosis, the causative agent of tuberculosis, but absent in humans. M. tuberculosis aroE-encoded shikimate dehydrogenase catalyzes the forth reaction in the shikimate pathway. Structural and functional studies indicate that Lysine69 may be involved in catalysis and/or substrate binding in M. tuberculosis shikimate dehydrogenase. Investigation of the kinetic properties of mutant enzymes can bring important insights about the role of amino acid residues for M. tuberculosis shikimate dehydrogenase. Findings We have performed site-directed mutagenesis, steady-state kinetics, equilibrium binding measurements and molecular modeling for both the wild-type M. tuberculosis shikimate dehydrogenase and the K69A mutant enzymes. The apparent steady-state kinetic parameters for the M. tuberculosis shikimate dehydrogenase were determined; the catalytic constant value for the wild-type enzyme (50 s-1 is 68-fold larger than that for the mutant K69A (0.73 s-1. There was a modest increase in the Michaelis-Menten constant for DHS (K69A = 76 μM; wild-type = 29 μM and NADPH (K69A = 30 μM; wild-type = 11 μM. The equilibrium dissociation constants for wild-type and K69A mutant enzymes are 32 (± 4 μM and 134 (± 21, respectively. Conclusion Our results show that the residue Lysine69 plays a catalytic role and is not involved in substrate binding for the M. tuberculosis shikimate dehydrogenase. These efforts on M. tuberculosis shikimate dehydrogenase catalytic mechanism determination should help the rational design of specific inhibitors, aiming at the development of antitubercular drugs.

  7. A computational tool to predict the evolutionarily conserved protein-protein interaction hot-spot residues from the structure of the unbound protein.

    Science.gov (United States)

    Agrawal, Neeraj J; Helk, Bernhard; Trout, Bernhardt L

    2014-01-21

    Identifying hot-spot residues - residues that are critical to protein-protein binding - can help to elucidate a protein's function and assist in designing therapeutic molecules to target those residues. We present a novel computational tool, termed spatial-interaction-map (SIM), to predict the hot-spot residues of an evolutionarily conserved protein-protein interaction from the structure of an unbound protein alone. SIM can predict the protein hot-spot residues with an accuracy of 36-57%. Thus, the SIM tool can be used to predict the yet unknown hot-spot residues for many proteins for which the structure of the protein-protein complexes are not available, thereby providing a clue to their functions and an opportunity to design therapeutic molecules to target these proteins. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  8. Cysteine-rich intestinal protein binds zinc during transmucosal zinc transport

    International Nuclear Information System (INIS)

    Hempe, J.M.; Cousins, R.J.

    1991-01-01

    The mechanism of zinc absorption has not been delineated, but kinetic studies show that both passive and carrier-mediated processes are involved. The authors have identified a low molecular mass zinc-binding protein in the soluble fraction of rat intestinal mucosa that could function as an intracellular zinc carrier. The protein was not detected in liver or pancreas, suggesting a role specific to the intestine. The protein binds zinc during transmucosal zinc transport and shows signs of saturation at higher luminal zinc concentrations, characteristics consistent with a role in carrier-mediated zinc absorption. Microsequence analysis of the protein purified by gel-filtration HPCL and SDS/PAGE showed complete identity within the first 41 N-terminal amino acids with the deduced protein sequence of cysteine-rich intestinal protein. These investigators showed that the gene for this protein is developmentally regulated in neonates during the suckling period, conserved in many vertebrate species, and predominantly expressed in the small intestine. Cysteine-rich intestinal protein contains a recently identified conserved sequence of histidine and cysteine residues, the LIM motif, which our results suggest confers metal-binding properties that are important for zinc transport and/or functions of this micronutrient

  9. Conductive component after cochlear implantation in patients with residual hearing conservation.

    Science.gov (United States)

    Chole, Richard A; Hullar, Timothy E; Potts, Lisa G

    2014-12-01

    Changes in auditory thresholds following cochlear implantation are generally assumed to be due to damage to neural elements. Theoretical studies have suggested that placement of a cochlear implant can cause a conductive hearing loss. Identification of a conductive component following cochlear implantation could guide improvements in surgical techniques or device designs. The purpose of this study is to characterize new-onset conductive hearing losses after cochlear implantation. In a prospective study, air- and bone-conduction audiometric testing were completed on cochlear implant recipients. An air-bone gap equal to or greater than 15 dB HL at 2 frequencies determined the presence of a conductive component. Of the 32 patients with preoperative bone-conduction hearing, 4 patients had a new-onset conductive component resulting in a mixed hearing loss, with air-conduction thresholds ranging from moderate to profound and an average air-bone gap of 30 dB HL. One had been implanted through the round window, 2 had an extended round window, and 1 had a separate cochleostomy. Loss of residual hearing following cochlear implantation may be due in part to a conductive component. Identifying the mechanism for this conductive component may help minimize hearing loss. Postoperative hearing evaluation should measure both air- and bone-conduction thresholds.

  10. The Effect of Conservation Tillage and Cover Crop Residue on Beneficial Arthropods and Weed Seed Predation in Acorn Squash.

    Science.gov (United States)

    Quinn, N F; Brainard, D C; Szendrei, Z

    2016-12-01

    Conservation tillage combined with cover crops or mulching may enhance natural enemy activity in agroecosystems by reducing soil disturbance and increasing habitat structural complexity. In particular, weed seed predation can increase with vegetation cover and reduced tillage, indicating that mulches may improve the quality of the habitat for weed seed foraging. The purpose of this study was to quantify the effects of tillage and mulching for conservation biological control in cucurbit fields. The effects of mulch and reduced tillage on arthropods and rates of weed seed loss from arenas were examined in field trials on sandy soils in 2014 and 2015. Experimental factors included tillage and cover crop, each with two levels: strip-tillage or full-tillage, and cover crop mulch (rye residue) or no cover crop mulch (unmulched). Arthropod abundance on the crop foliage was not affected by tillage or cover crops. Contrary to expectations, epigeal natural enemies of insects and rates of weed seed removal either did not respond to treatments or were greater in full-tilled plots and plots without mulch. Our study demonstrates the potential importance of weed seed predators in reducing weed seedbanks in vegetable agroecosystems, and suggests that early-season tillage may not be detrimental to epigeal predator assemblages. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. The formation of a native-like structure containing eight conserved hydrophobic residues is rate limiting in two-state protein folding of ACBP

    DEFF Research Database (Denmark)

    Kragelund, Birthe Brandt; Osmark, Peter; Neergaard, Thomas B.

    1999-01-01

    The acyl-coenzyme A-binding proteins (ACBPs) contain 26 highly conserved sequence positions. The majority of these have been mutated in the bovine protein, and their influence on the rate of two-state folding and unfolding has been measured. The results identify eight sequence positions, out of 24...... probed, that are critical for fast productive folding. The residues are all hydrophobic and located in the interface between the N- and C-terminal helices. The results suggest that one specific site dominated by conserved hydrophobic residues forms the structure of the productive rate-determining folding...... step and that a sequential framework model can describe the protein folding reaction....

  12. π-Clamp-mediated cysteine conjugation

    Science.gov (United States)

    Zhang, Chi; Welborn, Matthew; Zhu, Tianyu; Yang, Nicole J.; Santos, Michael S.; van Voorhis, Troy; Pentelute, Bradley L.

    2016-02-01

    Site-selective functionalization of complex molecules is one of the most significant challenges in chemistry. Typically, protecting groups or catalysts must be used to enable the selective modification of one site among many that are similarly reactive, and general strategies that selectively tune the local chemical environment around a target site are rare. Here, we show a four-amino-acid sequence (Phe-Cys-Pro-Phe), which we call the ‘π-clamp’, that tunes the reactivity of its cysteine thiol for site-selective conjugation with perfluoroaromatic reagents. We use the π-clamp to selectively modify one cysteine site in proteins containing multiple endogenous cysteine residues. These examples include antibodies and cysteine-based enzymes that would be difficult to modify selectively using standard cysteine-based methods. Antibodies modified using the π-clamp retained binding affinity to their targets, enabling the synthesis of site-specific antibody-drug conjugates for selective killing of HER2-positive breast cancer cells. The π-clamp is an unexpected approach to mediate site-selective chemistry and provides new avenues to modify biomolecules for research and therapeutics.

  13. [Plant signaling peptides. Cysteine-rich peptides].

    Science.gov (United States)

    Ostrowski, Maciej; Kowalczyk, Stanisław

    2015-01-01

    Recent bioinformatic and genetic analyses of several model plant genomes have revealed the existence of a highly abundant group of signaling peptides that are defined as cysteine-rich peptides (CRPs). CRPs are usually in size between 50 and 90 amino acid residues, they are positively charged, and they contain 4-16 cysteine residues that are important for the correct conformational folding. Despite the structural differences among CRP classes, members from each class have striking similarities in their molecular properties and function. The present review presents the recent progress in research on signaling peptides from several families including: EPF/EPFL, SP11/SCR, PrsS, RALF, LURE, and some other peptides belonging to CRP group. There is convincing evidence indicating multiple roles for these CRPs as signaling molecules during the plant life cycle, ranging from stomata development and patterning, self-incompatibility, pollen tube growth and guidance, reproductive processes, and nodule formation.

  14. Highly conserved serine residue 40 in HIV-1 p6 regulates capsid processing and virus core assembly

    Directory of Open Access Journals (Sweden)

    Solbak Sara MØ

    2011-02-01

    Full Text Available Abstract Background The HIV-1 p6 Gag protein regulates the final abscission step of nascent virions from the cell membrane by the action of two late assembly (L- domains. Although p6 is located within one of the most polymorphic regions of the HIV-1 gag gene, the 52 amino acid peptide binds at least to two cellular budding factors (Tsg101 and ALIX, is a substrate for phosphorylation, ubiquitination, and sumoylation, and mediates the incorporation of the HIV-1 accessory protein Vpr into viral particles. As expected, known functional domains mostly overlap with several conserved residues in p6. In this study, we investigated the importance of the highly conserved serine residue at position 40, which until now has not been assigned to any known function of p6. Results Consistently with previous data, we found that mutation of Ser-40 has no effect on ALIX mediated rescue of HIV-1 L-domain mutants. However, the only feasible S40F mutation that preserves the overlapping pol open reading frame (ORF reduces virus replication in T-cell lines and in human lymphocyte tissue cultivated ex vivo. Most intriguingly, L-domain mediated virus release is not dependent on the integrity of Ser-40. However, the S40F mutation significantly reduces the specific infectivity of released virions. Further, it was observed that mutation of Ser-40 selectively interferes with the cleavage between capsid (CA and the spacer peptide SP1 in Gag, without affecting cleavage of other Gag products. This deficiency in processing of CA, in consequence, led to an irregular morphology of the virus core and the formation of an electron dense extra core structure. Moreover, the defects induced by the S40F mutation in p6 can be rescued by the A1V mutation in SP1 that generally enhances processing of the CA-SP1 cleavage site. Conclusions Overall, these data support a so far unrecognized function of p6 mediated by Ser-40 that occurs independently of the L-domain function, but selectively

  15. Structure and mechanism of a cysteine sulfinate desulfinase engineered on the aspartate aminotransferase scaffold.

    Science.gov (United States)

    Fernandez, Francisco J; de Vries, Dominique; Peña-Soler, Esther; Coll, Miquel; Christen, Philipp; Gehring, Heinz; Vega, M Cristina

    2012-02-01

    The joint substitution of three active-site residues in Escherichia coli (L)-aspartate aminotransferase increases the ratio of l-cysteine sulfinate desulfinase to transaminase activity 10(5)-fold. This change in reaction specificity results from combining a tyrosine-shift double mutation (Y214Q/R280Y) with a non-conservative substitution of a substrate-binding residue (I33Q). Tyr214 hydrogen bonds with O3 of the cofactor and is close to Arg374 which binds the α-carboxylate group of the substrate; Arg280 interacts with the distal carboxylate group of the substrate; and Ile33 is part of the hydrophobic patch near the entrance to the active site, presumably participating in the domain closure essential for the transamination reaction. In the triple-mutant enzyme, k(cat)' for desulfination of l-cysteine sulfinate increased to 0.5s(-1) (from 0.05s(-1) in wild-type enzyme), whereas k(cat)' for transamination of the same substrate was reduced from 510s(-1) to 0.05s(-1). Similarly, k(cat)' for β-decarboxylation of l-aspartate increased fromcat)' for transamination was reduced from 530s(-1) to 0.13s(-1). l-Aspartate aminotransferase had thus been converted into an l-cysteine sulfinate desulfinase that catalyzes transamination and l-aspartate β-decarboxylation as side reactions. The X-ray structures of the engineered l-cysteine sulfinate desulfinase in its pyridoxal-5'-phosphate and pyridoxamine-5'-phosphate form or liganded with a covalent coenzyme-substrate adduct identified the subtle structural changes that suffice for generating desulfinase activity and concomitantly abolishing transaminase activity toward dicarboxylic amino acids. Apparently, the triple mutation impairs the domain closure thus favoring reprotonation of alternative acceptor sites in coenzyme-substrate intermediates by bulk water. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Reversible targeting of noncatalytic cysteines with chemically tuned electrophiles

    DEFF Research Database (Denmark)

    Serafimova, Iana M; Pufall, Miles A; Krishnan, Shyam

    2012-01-01

    Targeting noncatalytic cysteine residues with irreversible acrylamide-based inhibitors is a powerful approach for enhancing pharmacological potency and selectivity. Nevertheless, concerns about off-target modification motivate the development of reversible cysteine-targeting strategies. Here we...... of these electrophiles into a noncovalent kinase-recognition scaffold produced slowly dissociating, covalent inhibitors of the p90 ribosomal protein S6 kinase RSK2. A cocrystal structure revealed specific noncovalent interactions that stabilize the complex by positioning the electrophilic carbon near the targeted...

  17. Conserved Residues Lys57 and Lys401 of Protein Disulfide Isomerase Maintain an Active Site Conformation for Optimal Activity: Implications for Post-Translational Regulation

    Directory of Open Access Journals (Sweden)

    Cody Caba

    2018-02-01

    Full Text Available Despite its study since the 1960's, very little is known about the post-translational regulation of the multiple catalytic activities performed by protein disulfide isomerase (PDI, the primary protein folding catalyst of the cell. This work identifies a functional role for the highly conserved CxxC-flanking residues Lys57 and Lys401 of human PDI in vitro. Mutagenesis studies have revealed these residues as modulating the oxidoreductase activity of PDI in a pH-dependent manner. Non-conservative amino acid substitutions resulted in enzyme variants upwards of 7-fold less efficient. This attenuated activity was found to translate into a 2-fold reduction of the rate of electron shuttling between PDI and the intraluminal endoplasmic reticulum oxidase, ERO1α, suggesting a functional significance to oxidative protein folding. In light of this, the possibility of lysine acetylation at residues Lys57 and Lys401 was assessed by in vitro treatment using acetylsalicylic acid (aspirin. A total of 28 acetyllysine residues were identified, including acLys57 and acLys401. The kinetic behavior of the acetylated protein form nearly mimicked that obtained with a K57/401Q double substitution variant providing an indication that acetylation of the active site-flanking lysine residues can act to reversibly modulate PDI activity.

  18. Conserved Residues Lys57 and Lys401 of Protein Disulfide Isomerase Maintain an Active Site Conformation for Optimal Activity: Implications for Post-Translational Regulation.

    Science.gov (United States)

    Caba, Cody; Ali Khan, Hyder; Auld, Janeen; Ushioda, Ryo; Araki, Kazutaka; Nagata, Kazuhiro; Mutus, Bulent

    2018-01-01

    Despite its study since the 1960's, very little is known about the post-translational regulation of the multiple catalytic activities performed by protein disulfide isomerase (PDI), the primary protein folding catalyst of the cell. This work identifies a functional role for the highly conserved CxxC-flanking residues Lys 57 and Lys 401 of human PDI in vitro . Mutagenesis studies have revealed these residues as modulating the oxidoreductase activity of PDI in a pH-dependent manner. Non-conservative amino acid substitutions resulted in enzyme variants upwards of 7-fold less efficient. This attenuated activity was found to translate into a 2-fold reduction of the rate of electron shuttling between PDI and the intraluminal endoplasmic reticulum oxidase, ERO1α, suggesting a functional significance to oxidative protein folding. In light of this, the possibility of lysine acetylation at residues Lys 57 and Lys 401 was assessed by in vitro treatment using acetylsalicylic acid (aspirin). A total of 28 acetyllysine residues were identified, including acLys 57 and acLys 401 . The kinetic behavior of the acetylated protein form nearly mimicked that obtained with a K57/401Q double substitution variant providing an indication that acetylation of the active site-flanking lysine residues can act to reversibly modulate PDI activity.

  19. Identification and preliminary characterization of protein-cysteine farnesyltransferase

    International Nuclear Information System (INIS)

    Manne, V.; Roberts, D.; Tobin, A.; O'Rourke, E.; Barbacid, M.; De Virgilio, M.; Meyers, C.; Ahmed, N.; Kurz, B.; Resh, M.; Kung, Hsiang-Fu

    1990-01-01

    Ras proteins must be isoprenylated at a conserved cysteine residue near the carboxyl terminus in order to exert their biological activity. Previous studies indicate that an intermediate in the mevalonate pathway, most likely farnesyl pyrophosphate, is the donor of this isoprenyl group. Inhibition of mevalonate synthesis reverts the abnormal phenotypes induced by the mutant RAS2 Valendash19 gene in Saccharomyces cerevisiae and blocks the maturation of Xenopus oocytes induced by an onocogenic Ras p21 protein of human origin. These results have raised the possibility of using inhibitors of the mevalonate pathway to block the transforming properties of ras oncogenes. Unfortunately, mevalonate is a precursor of various end products essential to mammalian cells, such as dolichols, ubiquinones, heme A, and cholesterol. In this study, the authors describe an enzymatic activity(ies) capable of catalyzing the farnesylation of unprocessed Ras p21 proteins in vitro at the correct (Cys-186) residue. Gel filtration analysis of a partially purified preparation of protein farnesyltransferase revealed two peaks of activity at 250-350 kDa and 80-130 kDa. Availability of an in vitro protein farnesyltransferase assay should be useful in screening for potential inhibitors of ras oncogene function that will not interfere with other aspects of the mevalonate pathway

  20. Using a consensus approach based on the conservation of inter-residue contacts to rank CAPRI models

    KAUST Repository

    Vangone, Anna

    2013-10-17

    Herein we propose the use of a consensus approach, CONSRANK, for ranking CAPRI models. CONSRANK relies on the conservation of inter-residue contacts in the analyzed decoys ensemble. Models are ranked according to their ability to match the most frequently observed contacts. We applied CONSRANK to 19 CAPRI protein-protein targets, covering a wide range of prediction difficulty and involved in a variety of biological functions. CONSRANK results are consistently good, both in terms of native-like (NL) solutions ranked in the top positions and of values of the Area Under the receiver operating characteristic Curve (AUC). For targets having a percentage of NL solutions above 3%, an excellent performance is found, with AUC values approaching 1. For the difficult target T46, having only 3.4% NL solutions, the number of NL solutions in the top 5 and 10 ranked positions is enriched by a factor 30, and the AUC value is as high as 0.997. AUC values below 0.8 are only found for targets featuring a percentage of NL solutions within 1.1%. Remarkably, a false consensus emerges only in one case, T42, which happens to be an artificial protein, whose assembly details remain uncertain, based on controversial experimental data. We also show that CONSRANK still performs very well on a limited number of models, provided that more than 1 NL solution is included in the ensemble, thus extending its applicability to cases where few dozens of models are available.© 2013 Wiley Periodicals, Inc.

  1. Electrostatic influence of local cysteine environments on disulfide exchange kinetics.

    Science.gov (United States)

    Snyder, G H; Cennerazzo, M J; Karalis, A J; Field, D

    1981-11-10

    The ionic strength dependence of the bimolecular rate constant for reaction of the negative disulfide 5,5'-dithiobis (2-nitrobenzoic acid) with cysteines in fragments of naturally occurring proteins was determined by stopped-flow spectroscopy. The Debye-Hückel relationship was applied to determine the effective charge at the cysteine and thereby determine the extent to which nearby neighbors in the primary sequence influence the kinetics. Corrections for the secondary salt effect on cysteine pKs were determined by direct spectrometric pH titration of sulfhydryl groups or by observation of the ionic strength dependence of kinetics of cysteine reaction with the neutral disulfide 2,2'-dithiodipyridine. Quantitative expressions was verified by model studies with N-acetyl-cystein. At ionic strengths equal to or greater than 20 mM, the net charge at the polypeptide cysteine site is the sum of the single negative charge of the thiolate anion and the charges of the amino acids immediately preceding and following the cysteine in the primary sequence. At lower ionic strengths, more distant residues influence kinetics. At pH 7.0, 23 degree C, and an ionic strength of 20 mM, rate constants for reaction of the negative disulfide with a cysteine having two positive neighbors, one positive and one neutral neighbor, or two neutral neighbors are 132000, 3350, and 367 s-1 M-1, respectively. This corresponds to a contribution to the activation energy of 0.65- 1.1 kcal/mol per ion pair involved in collision between the cysteine and disulfide regions. The results permit the estimation that cysteine local environments may provide a means of achieving a 10(6)-fold range in rate constants in disulfide exchange reactions in random-coil proteins. This range may prove useful in developing strategies for directing disulfide pairing in synthetic proteins.

  2. Role of Conserved Disulfide Bridges and Aromatic Residues in Extracellular Loop 2 of Chemokine Receptor CCR8 for Chemokine and Small Molecule Binding

    DEFF Research Database (Denmark)

    Barington, Line; Rummel, Pia C; Lückmann, Michael

    2016-01-01

    and aromatic residues in extracellular loop 2 (ECL2) for ligand binding and activation in the chemokine receptor CCR8. We used IP3 accumulation and radioligand binding experiments to determine the impact of receptor mutagenesis on both chemokine and small molecule agonist and antagonist binding and action...... in CCR8. We find that the 7 transmembrane (7TM) receptor conserved disulfide bridge (7TM bridge) linking transmembrane helix (TM)III and ECL2 is crucial for chemokine and small molecule action, whereas the chemokine receptor conserved disulfide bridge between the N terminus and TMVII is needed only...

  3. Alanine substitution of conserved residues in the cytoplasmic tail of herpes simplex virus gB can enhance or abolish cell fusion activity and viral entry

    International Nuclear Information System (INIS)

    Ruel, Nancy; Zago, Anna; Spear, Patricia G.

    2006-01-01

    Herpes simplex virus (HSV) glycoprotein B (gB) is one of the four viral glycoproteins required for viral entry and cell fusion and is highly conserved among herpesviruses. Mutants of HSV type 2 gB were generated by substituting conserved residues in the cytoplasmic tail with alanine or by deleting 41 amino acids from the C-terminus. Some of the mutations abolished cell fusion activity and also prevented transport of gB to the cell surface, identifying residues in the gB cytoplasmic tail that are critical for intracellular transport of this glycoprotein. These mutations also prevented production of infectious virus, possibly because the mutant forms of gB were not transported to the site of envelopment. Other mutations, particularly the deletion, significantly enhanced cell fusion activity. These mutations, as well as others described previously, identify regions of the gB cytoplasmic domain that modulate cell fusion activity

  4. Conserved residues in the coiled-coil pocket of human immunodeficiency virus type 1 gp41 are essential for viral replication and interhelical interaction

    International Nuclear Information System (INIS)

    Mo Hongmei; Konstantinidis, Alex K.; Stewart, Kent D.; Dekhtyar, Tatyana; Ng, Teresa; Swift, Kerry; Matayoshi, Edmund D.; Kati, Warren; Kohlbrenner, William; Molla, Akhteruzzaman

    2004-01-01

    The human immunodeficiency virus type 1 (HIV-1) gp41 plays an important role in mediating the fusion of HIV with host cells. During the fusion process, three N-terminal helices and three C-terminal helices pack in an anti-parallel direction to form a six-helix bundle. X-ray crystallographic analysis of the gp41 core demonstrated that within each coiled-coil interface, there is a deep and large pocket, formed by a cluster of residues in the N-helix coiled-coil. In this report, we systematically analyzed the role of seven conserved residues that are either lining or packing this pocket on the infectivity and interhelical interaction using novel approaches. Our results show that residues L568, V570, W571, and K574 of the N-helix that are lining the side chain and right wall of the pocket are important for establishing a productive infection. Mutations V570A and W571A completely abolished replication, while replication of the L568A and K574A mutants was significantly attenuated relative to wild type. Similarly, residues W628, W631, and I635 of the C-helix that insert into the pocket are essential for infectivity. The impaired infectivity of these seven mutants is in part attributed to the loss in binding affinity of the interhelical interaction. Molecular modeling of the crystal structure of the coiled-coil further shows that alanine substitution of those residues disrupts the hydrophobic interaction between the N- and C-helix. These results suggest that the conserved residues in the coiled-coil domain play a key role in HIV infection and this coiled-coil pocket is a good target for development of inhibitors against HIV. In addition, our data indicate that the novel fluorescence polarization assay described in this study could be valuable in screening for inhibitors that block the interhelical interaction and HIV entry

  5. Measuring site occupancy: a new perspective on cysteine oxidation.

    Science.gov (United States)

    Rogowska-Wrzesinska, Adelina; Wojdyla, Katarzyna; Williamson, James; Roepstorff, Peter

    2014-10-01

    Site occupancy is an extremely important aspect of quantification of protein modifications. Knowing the degree of modification of each oxidised cysteine residue is critical to understanding the biological role of these modifications. Yet modification site occupancy is very often overlooked, in part because there are very few analytical tools that allow such measurements. Here we present a new strategy, which provides quantitative analysis of cysteine S-nitrosylation (SNO) and S-sulfenylation (SOH) simultaneously at the resolution of single cysteine and allows for determination of relative oxidation occupancy of the modification site. We show that, on one hand, heavily modified cysteines are not necessarily involved in the response to oxidative stress. On the other hand residues with low modification level can be dramatically affected by mild oxidative imbalance. We make use of high resolution mass spectrometry. The method relies on differential reduction of "total" cysteines, SNO cysteines and SOH cysteines with TCEP, sodium ascorbate and sodium arsenite respectively followed by iodoTMT(TM) alkylation. Enrichment of iodoTMT(TM)-containing peptides is performed using anti-TMT antibody. In vivo model of mild oxidative stress in Escherichia coli is used. To induce endogenous SNO bacteria were grown anaerobically in minimal media supplemented with fumarate or nitrate. Short-term treatment with submilimolar levels of hydrogen peroxide were used to induce SOH. We have quantified 114 SNO/SOH modified peptides corresponding to 90 proteins. Only 6 modified peptides changed significantly under mild oxidative stress. Quantitative information allowed us to determine relative modification site occupancy of each identified modified residue and pin point heavily modified ones. The method proved to be precise and sensitive enough to detect and quantify endogenous levels of oxidative stress on proteome-wide scale and brings a new perspective on the role of the modification site

  6. The conserved glycine residues in the transmembrane domain of the Semliki Forest virus fusion protein are not required for assembly and fusion

    International Nuclear Information System (INIS)

    Liao Maofu; Kielian, Margaret

    2005-01-01

    The alphavirus Semliki Forest virus (SFV) infects cells via a low pH-triggered fusion reaction mediated by the viral E1 protein. Both the E1 fusion peptide and transmembrane (TM) domain are essential for membrane fusion, but the functional requirements for the TM domain are poorly understood. Here we explored the role of the five TM domain glycine residues, including the highly conserved glycine pair at E1 residues 415/416. SFV mutants with alanine substitutions for individual or all five glycine residues (5G/A) showed growth kinetics and fusion pH dependence similar to those of wild-type SFV. Mutants with increasing substitution of glycine residues showed an increasingly more stringent requirement for cholesterol during fusion. The 5G/A mutant showed decreased fusion kinetics and extent in fluorescent lipid mixing assays. TM domain glycine residues thus are not required for efficient SFV fusion or assembly but can cause subtle effects on the properties of membrane fusion

  7. The conserved residue Arg46 in the N-terminal heptad repeat domain of HIV-1 gp41 is critical for viral fusion and entry.

    Directory of Open Access Journals (Sweden)

    Xiaoyi Wang

    Full Text Available During the process of HIV-1 fusion with the target cell, the N-terminal heptad repeat (NHR of gp41 interacts with the C-terminal heptad repeat (CHR to form fusogenic six-helix bundle (6-HB core. We previously identified a crucial residue for 6-HB formation and virus entry--Lys63 (K63 in the C-terminal region of NHR (aa 54-70, which forms a hydrophobic cavity. It can form an important salt bridge with Asp121 (D121 in gp41 CHR. Here, we found another important conserved residue for virus fusion and entry, Arg46 (R46, in the N-terminal region of NHR (aa 35-53, which forms a hydrogen bond with a polar residue, Asn43 (N43, in NHR, as a part of the hydrogen-bond network. R46 can also form a salt bridge with a negatively charged residue, Glu137 (E137, in gp41 CHR. Substitution of R46 with the hydrophobic residue Ala (R46A or the negatively charged residue Glu (R46E resulted in disruption of the hydrogen bond network, breakage of the salt bridge and reduction of 6-HB's stability, leading to impairment of viral fusion and decreased inhibition of N36, an NHR peptide. Similarly, CHR peptide C34 with substitution of E137 for Ala (E137A or Arg (E137R also exhibited reduced inhibitory activity against HIV-1 infection and HIV-1-mediated cell-to-cell fusion. These results suggest that the positively charged residue R46 and its hydrogen bond network, together with the salt bridge between R46 and E137, are important for viral fusion and entry and may therefore serve as a target for designing novel HIV fusion/entry inhibitors.

  8. The conserved basic residues and the charged amino acid residues at the α-helix of the zinc finger motif regulate the nuclear transport activity of triple C2H2 zinc finger proteins

    Science.gov (United States)

    Lin, Chih-Ying

    2018-01-01

    Zinc finger (ZF) motifs on proteins are frequently recognized as a structure for DNA binding. Accumulated reports indicate that ZF motifs contain nuclear localization signal (NLS) to facilitate the transport of ZF proteins into nucleus. We investigated the critical factors that facilitate the nuclear transport of triple C2H2 ZF proteins. Three conserved basic residues (hot spots) were identified among the ZF sequences of triple C2H2 ZF proteins that reportedly have NLS function. Additional basic residues can be found on the α-helix of the ZFs. Using the ZF domain (ZFD) of Egr-1 as a template, various mutants were constructed and expressed in cells. The nuclear transport activity of various mutants was estimated by analyzing the proportion of protein localized in the nucleus. Mutation at any hot spot of the Egr-1 ZFs reduced the nuclear transport activity. Changes of the basic residues at the α-helical region of the second ZF (ZF2) of the Egr-1 ZFD abolished the NLS activity. However, this activity can be restored by substituting the acidic residues at the homologous positions of ZF1 or ZF3 with basic residues. The restored activity dropped again when the hot spots at ZF1 or the basic residues in the α-helix of ZF3 were mutated. The variations in nuclear transport activity are linked directly to the binding activity of the ZF proteins with importins. This study was extended to other triple C2H2 ZF proteins. SP1 and KLF families, similar to Egr-1, have charged amino acid residues at the second (α2) and the third (α3) positions of the α-helix. Replacing the amino acids at α2 and α3 with acidic residues reduced the NLS activity of the SP1 and KLF6 ZFD. The reduced activity can be restored by substituting the α3 with histidine at any SP1 and KLF6 ZFD. The results show again the interchangeable role of ZFs and charge residues in the α-helix in regulating the NLS activity of triple C2H2 ZF proteins. PMID:29381770

  9. NMR WaterLOGSY Reveals Weak Binding of Bisphenol A with Amyloid Fibers of a Conserved 11 Residue Peptide from Androgen Receptor.

    Directory of Open Access Journals (Sweden)

    Julia Asencio-Hernández

    Full Text Available There is growing evidence that bisphenol A (BPA, a molecule largely released in the environment, has detrimental effects on ecosystems and on human health. It acts as an endocrine disruptor targeting steroid hormone receptors, such as the estrogen receptor (ER, estrogen-related receptor (ERR and androgen receptor (AR. BPA-derived molecules have recently been shown to interact with the AR N-terminal domain (AR-NTD, which is known to be largely intrinsically disordered. This N-terminal domain contains an 11 residue conserved domain that forms amyloid fibers upon oxidative dimerisation through its strictly conserved Cys240 residue. We investigate here the interaction of BPA, and other potential endocrine disruptors, with AR-NTD amyloid fibers using the WaterLOGSY NMR experiment. We observed a selective binding of these compounds to the amyloid fibers formed by the AR-NTD conserved region and glutamine homopolymers. This observation suggests that the high potency of endocrine disruptors may result, in part, from their ability to bind amyloid forms of nuclear receptors in addition to their cognate binding sites. This property may be exploited to design future therapeutic strategies targeting AR related diseases such as the spinal bulbar muscular atrophy or prostate cancer. The ability of NMR WaterLOGSY experiments to detect weak interactions between small ligands and amyloid fibers may prove to be of particular interest for identifying promising hit molecules.

  10. Computational analysis of perturbations in the post-fusion Dengue virus envelope protein highlights known epitopes and conserved residues in the Zika virus [version 2; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Sandeep Chakraborty

    2016-09-01

    Full Text Available The dramatic transformation of the Zika virus (ZIKV from a relatively unknown virus to a pathogen generating global-wide panic has exposed the dearth of detailed knowledge about this virus. Decades of research in the related Dengue virus (DENV, finally culminating in a vaccine registered for use in endemic regions (CYD-TDV in three countries, provides key insights in developing strategies for tackling ZIKV, which has caused global panic to microcephaly and Guillain-Barre Syndrome. Dengue virus (DENV, a member of the family Flaviviridae, the causal agent of the self-limiting Dengue fever and the potentially fatal hemorrhagic fever/dengue shock syndrome, has been a scourge in tropical countries for many centuries. The recently solved structure of mature ZIKV (PDB ID:5IRE has provided key insights into the structure of the envelope (E and membrane (M proteins, the primary target of neutralizing antibodies. The previously established MEPP methodology compares two conformations of the same protein and identifies residues with significant spatial and electrostatic perturbations. In the current work, MEPP analyzed the pre-and post-fusion DENV type 2 envelope (E protein, and identified several known epitopes (His317, Tyr299, Glu26, Arg188, etc. (MEPPitope. These residues are overwhelmingly conserved in ZIKV and all DENV serotypes, and also enumerates residue pairs that undergo significant polarity reversal. Characterization of α-helices in E-proteins show that α1 is not conserved in the sequence space of ZIKV and DENV. Furthermore, perturbation of α1 in the post-fusion DENV structure includes a known epitope Asp215, a residue absent in the pre-fusion α1. A cationic β-sheet in the GAG-binding domain that is stereochemically equivalent in ZIKV and all DENV serotypes is also highlighted due to a residue pair (Arg286-Arg288 that has a significant electrostatic polarity reversal upon fusion. Finally, two highly conserved residues (Thr32 and Thr40, with

  11. Structural basis for new pattern of conserved amino acid residues related to chitin-binding in the antifungal peptide from the coconut rhinoceros beetle Oryctes rhinoceros.

    Science.gov (United States)

    Hemmi, Hikaru; Ishibashi, Jun; Tomie, Tetsuya; Yamakawa, Minoru

    2003-06-20

    Scarabaecin isolated from hemolymph of the coconut rhinoceros beetle Oryctes rhinoceros is a 36-residue polypeptide that has antifungal activity. The solution structure of scarabaecin has been determined from twodimensional 1H NMR spectroscopic data and hybrid distance geometry-simulated annealing protocol calculation. Based on 492 interproton and 10 hydrogen-bonding distance restraints and 36 dihedral angle restraints, we obtained 20 structures. The average backbone root-mean-square deviation for residues 4-35 is 0.728 +/- 0.217 A from the mean structure. The solution structure consists of a two-stranded antiparallel beta-sheet connected by a type-I beta-turn after a short helical turn. All secondary structures and a conserved disulfide bond are located in the C-terminal half of the peptide, residues 18-36. Overall folding is stabilized by a combination of a disulfide bond, seven hydrogen bonds, and numerous hydrophobic interactions. The structural motif of the C-terminal half shares a significant tertiary structural similarity with chitin-binding domains of plant and invertebrate chitin-binding proteins, even though scarabaecin has no overall sequence similarity to other peptide/polypeptides including chitin-binding proteins. The length of its primary structure, the number of disulfide bonds, and the pattern of conserved functional residues binding to chitin in scarabaecin differ from those of chitin-binding proteins in other invertebrates and plants, suggesting that scarabaecin does not share a common ancestor with them. These results are thought to provide further strong experimental evidence to the hypothesis that chitin-binding proteins of invertebrates and plants are correlated by a convergent evolution process.

  12. Energy conservation and production from solid residues - alternative for two problems: wastes and energy; Conservacao e producao de energia a partir de residuos solidos - alternativa para dois problemas: lixo e energia

    Energy Technology Data Exchange (ETDEWEB)

    Reno, Francisco de Assis Grillo [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Planejamento de Sistemas Energeticos]. E-mail: fgrillo@fem.unicamp.br; Streb, Cleci Schalemberger [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica; Piunti, Regina Celia [Universidade Estadual de Campinas, SP (Brazil)]. E-mail: repiunti@ig.com.br

    2002-07-01

    This paper explores possibilities of energy conservation and production through the using domestic solid residues, aiming the disposal impacts and improvement the energy supplying as well. For energy conservation,the recycling, reduction and re utilization will be mentioned. For the energy recovering the burning of organic material in sanitary landfill and incineration of plastics and tires.

  13. Conserved residues and their role in the structure, function, and stability of acyl-coenzyme A binding protein

    DEFF Research Database (Denmark)

    Kragelund, B B; Poulsen, K; Andersen, K V

    1999-01-01

    In the family of acyl-coenzyme A binding proteins, a subset of 26 sequence sites are identical in all eukaryotes and conserved throughout evolution of the eukaryotic kingdoms. In the context of the bovine protein, the importance of these 26 sequence positions for structure, function, stability...

  14. Atypical Thioredoxins in Poplar: The Glutathione-Dependent Thioredoxin-Like 2.1 Supports the Activity of Target Enzymes Possessing a Single Redox Active Cysteine1[W

    Science.gov (United States)

    Chibani, Kamel; Tarrago, Lionel; Gualberto, José Manuel; Wingsle, Gunnar; Rey, Pascal; Jacquot, Jean-Pierre; Rouhier, Nicolas

    2012-01-01

    Plant thioredoxins (Trxs) constitute a complex family of thiol oxidoreductases generally sharing a WCGPC active site sequence. Some recently identified plant Trxs (Clot, Trx-like1 and -2, Trx-lilium1, -2, and -3) display atypical active site sequences with altered residues between the two conserved cysteines. The transcript expression patterns, subcellular localizations, and biochemical properties of some representative poplar (Populus spp.) isoforms were investigated. Measurements of transcript levels for the 10 members in poplar organs indicate that most genes are constitutively expressed. Using transient expression of green fluorescent protein fusions, Clot and Trx-like1 were found to be mainly cytosolic, whereas Trx-like2.1 was located in plastids. All soluble recombinant proteins, except Clot, exhibited insulin reductase activity, although with variable efficiencies. Whereas Trx-like2.1 and Trx-lilium2.2 were efficiently regenerated both by NADPH-Trx reductase and glutathione, none of the proteins were reduced by the ferredoxin-Trx reductase. Only Trx-like2.1 supports the activity of plastidial thiol peroxidases and methionine sulfoxide reductases employing a single cysteine residue for catalysis and using a glutathione recycling system. The second active site cysteine of Trx-like2.1 is dispensable for this reaction, indicating that the protein possesses a glutaredoxin-like activity. Interestingly, the Trx-like2.1 active site replacement, from WCRKC to WCGPC, suppresses its capacity to use glutathione as a reductant but is sufficient to allow the regeneration of target proteins employing two cysteines for catalysis, indicating that the nature of the residues composing the active site sequence is crucial for substrate selectivity/recognition. This study provides another example of the cross talk existing between the glutathione/glutaredoxin and Trx-dependent pathways. PMID:22523226

  15. The Activity of Escherichia coli Dihydroorotate Dehydrogenase Is Dependent on a Conserved Loop Identified by Sequence Homology, Mutagenesis, and Limited Proteolysis

    DEFF Research Database (Denmark)

    Björnberg, Olof; Grüner, Anne Charlotte; Roepstorff, Peter

    1999-01-01

    of dihydroorotate dehydrogenases, but sedimentation in sucrose gradients suggests a dimeric structure also of the E. coli enzyme. Product inhibition showed that the E. coli enzyme, in contrast to the L. lactis enzyme, has separate binding sites for dihydroorotate and the electron acceptor. Trypsin readily cleaved...... the E. coli enzyme into two fragments of 182 and 154 residues, respectively. Cleavage reduced the activity more than 100-fold but left other molecular properties, including the heat stability, intact. The trypsin cleavage site, at R182, is positioned in a conserved region that, in the L. lactis enzyme......, forms a loop where a cysteine residue is very critical for activity. In the corresponding position, the enzyme from E. coli has a serine residue. Mutagenesis of this residue (S175) to alanine or cysteine reduced the activities 10000- and 500-fold, respectively. The S175C mutant was also defective...

  16. A conserved serine residue regulates the stability of Drosophila Salvador and human WW domain-containing adaptor 45 through proteasomal degradation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Di, E-mail: DiWu@mail.nankai.edu.cn; Wu, Shian

    2013-04-19

    Highlights: •Ser-17 is key for the stability of Drosophila Sav. •Ala mutation of Ser-17 promotes the proteasomal degradation of Sav. •Ser-17 residue is not the main target of Hpo-induced Sav stabilization. •Hpo-dependent and -independent mechanisms regulate Sav stability. •This mechanism is conserved in the homologue of Sav, human WW45. -- Abstract: The Hippo (Hpo) pathway is a conserved tumor suppressor pathway that controls organ size through the coordinated regulation of apoptosis and proliferation. Drosophila Salvador (Sav), which limits organ size, is a core component of the Hpo pathway. In this study, Ser-17 was shown to be important for the stability of Sav. Alanine mutation of Ser-17 promoted the proteasomal degradation of Sav. Destabilization and stabilization of the Sav protein mediated by alanine mutation of Ser-17 and by Hpo, respectively, were independent of each other. This implies that the stability of Sav is controlled by two mechanisms, one that is Ser-17-dependent and Hpo-independent, and another that is Ser-17-independent and Hpo-dependent. These dual mechanisms also regulated the human counterpart of Drosophila Sav, WW domain-containing adaptor 45 (WW45). The conservation of this regulation adds to its significance in normal physiology and tumorigenesis.

  17. Assay of cysteine dioxygenase activity

    International Nuclear Information System (INIS)

    Bagley, P.J.; Stipanuk, M.H.

    1990-01-01

    It has been proposed that rat liver contains two cysteine dioxygenase enzymes which convert cysteine to cysteinesulfinic acid, one which is stimulated by NAD + and has a pH optimum of 6.8 and one which is not stimulated by NAD + and has a pH optimum of 9.0. This led the authors to reinvestigate assay conditions for measuring cysteine dioxygenase activity in rat liver homogenate. An HPLC method, using an anion exchange column (Dionex Amino-Pac trademark PA1 (4x250 mm)) was used to separate the [ 35 S]cysteinesulfinic acid produced from [ 35 S]cysteine in the incubation mixture. They demonstrated that inclusion of hydroxylamine prevented further metabolism of cysteinesulfinic acid. which occurred rapidly in the absence of hydroxylamine

  18. Analysis of Margin Index as a Method for Predicting Residual Disease After Breast-Conserving Surgery in a European Cancer Center.

    LENUS (Irish Health Repository)

    Bolger, Jarlath C

    2011-06-03

    INTRODUCTION: Breast-conserving surgery (BCS), followed by appropriate adjuvant therapies is established as a standard treatment option for women with early-stage invasive breast cancers. A number of factors have been shown to correlate with local and regional disease recurrence. Although margin status is a strong predictor of disease recurrence, consensus is yet to be established on the optimum margin necessary. Margenthaler et al. recently proposed the use of a "margin index," combining tumor size and margin status as a predictor of residual disease after BCS. We applied this new predictive tool to a population of patients with primary breast cancer who presented to a symptomatic breast unit to determine its suitability in predicting those who require reexcision surgery. METHODS: Retrospective analysis of our breast cancer database from January 1, 2000 to June 30, 2010 was performed, including all patients who underwent BCS. Of 531 patients who underwent BCS, 27.1% (144\\/531) required further reexcision procedures, and 55 were eligible for inclusion in the study. Margin index was calculated as: margin index = closest margin (mm)\\/tumor size (mm) × 100, with index >5 considered optimum. RESULTS: Of the 55 patients included, 31% (17\\/55) had residual disease. Fisher\\'s exact test showed margin index not to be a significant predictor of residual disease on reexcision specimen (P = 0.57). Of note, a significantly higher proportion of our patients presented with T2\\/3 tumors (60% vs. 38%). CONCLUSIONS: Although an apparently elegant tool for predicting residual disease after BCS, we have shown that it is not applicable to a symptomatic breast unit in Ireland.

  19. Analysis of margin index as a method for predicting residual disease after breast-conserving surgery in a European cancer center.

    LENUS (Irish Health Repository)

    Bolger, Jarlath C

    2012-02-01

    INTRODUCTION: Breast-conserving surgery (BCS), followed by appropriate adjuvant therapies is established as a standard treatment option for women with early-stage invasive breast cancers. A number of factors have been shown to correlate with local and regional disease recurrence. Although margin status is a strong predictor of disease recurrence, consensus is yet to be established on the optimum margin necessary. Margenthaler et al. recently proposed the use of a "margin index," combining tumor size and margin status as a predictor of residual disease after BCS. We applied this new predictive tool to a population of patients with primary breast cancer who presented to a symptomatic breast unit to determine its suitability in predicting those who require reexcision surgery. METHODS: Retrospective analysis of our breast cancer database from January 1, 2000 to June 30, 2010 was performed, including all patients who underwent BCS. Of 531 patients who underwent BCS, 27.1% (144\\/531) required further reexcision procedures, and 55 were eligible for inclusion in the study. Margin index was calculated as: margin index = closest margin (mm)\\/tumor size (mm) x 100, with index >5 considered optimum. RESULTS: Of the 55 patients included, 31% (17\\/55) had residual disease. Fisher\\'s exact test showed margin index not to be a significant predictor of residual disease on reexcision specimen (P = 0.57). Of note, a significantly higher proportion of our patients presented with T2\\/3 tumors (60% vs. 38%). CONCLUSIONS: Although an apparently elegant tool for predicting residual disease after BCS, we have shown that it is not applicable to a symptomatic breast unit in Ireland.

  20. The Replacement of 10 Non-Conserved Residues in the Core Protein of JFH-1 Hepatitis C Virus Improves Its Assembly and Secretion.

    Directory of Open Access Journals (Sweden)

    Loïc Etienne

    Full Text Available Hepatitis C virus (HCV assembly is still poorly understood. It is thought that trafficking of the HCV core protein to the lipid droplet (LD surface is essential for its multimerization and association with newly synthesized HCV RNA to form the viral nucleocapsid. We carried out a mapping analysis of several complete HCV genomes of all genotypes, and found that the genotype 2 JFH-1 core protein contained 10 residues different from those of other genotypes. The replacement of these 10 residues of the JFH-1 strain sequence with the most conserved residues deduced from sequence alignments greatly increased virus production. Confocal microscopy of the modified JFH-1 strain in cell culture showed that the mutated JFH-1 core protein, C10M, was present mostly at the endoplasmic reticulum (ER membrane, but not at the surface of the LDs, even though its trafficking to these organelles was possible. The non-structural 5A protein of HCV was also redirected to ER membranes and colocalized with the C10M core protein. Using a Semliki forest virus vector to overproduce core protein, we demonstrated that the C10M core protein was able to form HCV-like particles, unlike the native JFH-1 core protein. Thus, the substitution of a few selected residues in the JFH-1 core protein modified the subcellular distribution and assembly properties of the protein. These findings suggest that the early steps of HCV assembly occur at the ER membrane rather than at the LD surface. The C10M-JFH-1 strain will be a valuable tool for further studies of HCV morphogenesis.

  1. Biotin Switch Assays for Quantitation of Reversible Cysteine Oxidation.

    Science.gov (United States)

    Li, R; Kast, J

    2017-01-01

    Thiol groups in protein cysteine residues can be subjected to different oxidative modifications by reactive oxygen/nitrogen species. Reversible cysteine oxidation, including S-nitrosylation, S-sulfenylation, S-glutathionylation, and disulfide formation, modulate multiple biological functions, such as enzyme catalysis, antioxidant, and other signaling pathways. However, the biological relevance of reversible cysteine oxidation is typically underestimated, in part due to the low abundance and high reactivity of some of these modifications, and the lack of methods to enrich and quantify them. To facilitate future research efforts, this chapter describes detailed procedures to target the different modifications using mass spectrometry-based biotin switch assays. By switching the modification of interest to a biotin moiety, these assays leverage the high affinity between biotin and avidin to enrich the modification. The use of stable isotope labeling and a range of selective reducing agents facilitate the quantitation of individual as well as total reversible cysteine oxidation. The biotin switch assay has been widely applied to the quantitative analysis of S-nitrosylation in different disease models and is now also emerging as a valuable research tool for other oxidative cysteine modifications, highlighting its relevance as a versatile, robust strategy for carrying out in-depth studies in redox proteomics. © 2017 Elsevier Inc. All rights reserved.

  2. Importance of a Conserved Lys/Arg Residue for Ligand/PDZ Domain Interactions as Examined by Protein Semisynthesis

    DEFF Research Database (Denmark)

    Pedersen, Søren W; Moran, Griffin E; Sereikaité, Vita

    2016-01-01

    PDZ domains are ubiquitous small protein domains that are mediators of numerous protein-protein interactions, and play a pivotal role in protein trafficking, synaptic transmission, and the assembly of signaling-transduction complexes. In recent years, PDZ domains have emerged as novel and exciting...... drug targets for diseases (in the brain in particular), so understanding the molecular details of PDZ domain interactions is of fundamental importance. PDZ domains bind to a protein partner at either a C-terminal peptide or internal peptide motifs. Here, we examined the importance of a conserved Lys...

  3. Vibrio Type III Effector VPA1380 Is Related to the Cysteine Protease Domain of Large Bacterial Toxins

    Science.gov (United States)

    Calder, Thomas; Kinch, Lisa N.; Fernandez, Jessie; Salomon, Dor; Grishin, Nick V.; Orth, Kim

    2014-01-01

    Vibrio parahaemolyticus is a Gram-negative halophilic bacterium and one of the leading causes of food-borne gastroenteritis. Its genome harbors two Type III Secretion Systems (T3SS1 and T3SS2), but only T3SS2 is required for enterotoxicity seen in animal models. Effector proteins secreted from T3SS2 have been previously shown to promote colonization of the intestinal epithelium, invasion of host cells, and destruction of the epithelial monolayer. In this study, we identify VPA1380, a T3SS2 effector protein that is toxic when expressed in yeast. Bioinformatic analyses revealed that VPA1380 is highly similar to the inositol hexakisphosphate (IP6)-inducible cysteine protease domains of several large bacterial toxins. Mutations in conserved catalytic residues and residues in the putative IP6-binding pocket abolished toxicity in yeast. Furthermore, VPA1380 was not toxic in IP6 deficient yeast cells. Therefore, our findings suggest that VPA1380 is a cysteine protease that requires IP6 as an activator. PMID:25099122

  4. Vibrio type III effector VPA1380 is related to the cysteine protease domain of large bacterial toxins.

    Directory of Open Access Journals (Sweden)

    Thomas Calder

    Full Text Available Vibrio parahaemolyticus is a Gram-negative halophilic bacterium and one of the leading causes of food-borne gastroenteritis. Its genome harbors two Type III Secretion Systems (T3SS1 and T3SS2, but only T3SS2 is required for enterotoxicity seen in animal models. Effector proteins secreted from T3SS2 have been previously shown to promote colonization of the intestinal epithelium, invasion of host cells, and destruction of the epithelial monolayer. In this study, we identify VPA1380, a T3SS2 effector protein that is toxic when expressed in yeast. Bioinformatic analyses revealed that VPA1380 is highly similar to the inositol hexakisphosphate (IP6-inducible cysteine protease domains of several large bacterial toxins. Mutations in conserved catalytic residues and residues in the putative IP6-binding pocket abolished toxicity in yeast. Furthermore, VPA1380 was not toxic in IP6 deficient yeast cells. Therefore, our findings suggest that VPA1380 is a cysteine protease that requires IP6 as an activator.

  5. A Conserved Metal Binding Motif in the Bacillus subtilis Competence Protein ComFA Enhances Transformation.

    Science.gov (United States)

    Chilton, Scott S; Falbel, Tanya G; Hromada, Susan; Burton, Briana M

    2017-08-01

    Genetic competence is a process in which cells are able to take up DNA from their environment, resulting in horizontal gene transfer, a major mechanism for generating diversity in bacteria. Many bacteria carry homologs of the central DNA uptake machinery that has been well characterized in Bacillus subtilis It has been postulated that the B. subtilis competence helicase ComFA belongs to the DEAD box family of helicases/translocases. Here, we made a series of mutants to analyze conserved amino acid motifs in several regions of B. subtilis ComFA. First, we confirmed that ComFA activity requires amino acid residues conserved among the DEAD box helicases, and second, we show that a zinc finger-like motif consisting of four cysteines is required for efficient transformation. Each cysteine in the motif is important, and mutation of at least two of the cysteines dramatically reduces transformation efficiency. Further, combining multiple cysteine mutations with the helicase mutations shows an additive phenotype. Our results suggest that the helicase and metal binding functions are two distinct activities important for ComFA function during transformation. IMPORTANCE ComFA is a highly conserved protein that has a role in DNA uptake during natural competence, a mechanism for horizontal gene transfer observed in many bacteria. Investigation of the details of the DNA uptake mechanism is important for understanding the ways in which bacteria gain new traits from their environment, such as drug resistance. To dissect the role of ComFA in the DNA uptake machinery, we introduced point mutations into several motifs in the protein sequence. We demonstrate that several amino acid motifs conserved among ComFA proteins are important for efficient transformation. This report is the first to demonstrate the functional requirement of an amino-terminal cysteine motif in ComFA. Copyright © 2017 American Society for Microbiology.

  6. Mechanistic Basis for Type 2 Long QT Syndrome Caused by KCNH2 Mutations that Disrupt Conserved Arginine Residue in the Voltage Sensor

    Science.gov (United States)

    McBride, Christie M.; Smith, Ashley M.; Smith, Jennifer L.; Reloj, Allison R.; Velasco, Ellyn J.; Powell, Jonathan; Elayi, Claude S.; Bartos, Daniel C.; Burgess, Don E.

    2013-01-01

    KCNH2 encodes the Kv11.1 channel, which conducts the rapidly activating delayed rectifier K+ current (IKr) in the heart. KCNH2 mutations cause type 2 long QT syndrome (LQT2), which increases the risk for life-threatening ventricular arrhythmias. LQT2 mutations are predicted to prolong the cardiac action potential (AP) by reducing IKr during repolarization. Kv11.1 contains several conserved basic amino acids in the fourth transmembrane segment (S4) of the voltage sensor that are important for normal channel trafficking and gating. This study sought to determine the mechanism(s) by which LQT2 mutations at conserved arginine residues in S4 (R531Q, R531W or R534L) alter Kv11.1 function. Western blot analyses of HEK293 cells transiently expressing R531Q, R531W or R534L suggested that only R534L inhibited Kv11.1 trafficking. Voltage-clamping experiments showed that R531Q or R531W dramatically altered Kv11.1 current (IKv11.1) activation, inactivation, recovery from inactivation and deactivation. Coexpression of wild type (to mimic the patients’ genotypes) mostly corrected the changes in IKv11.1 activation and inactivation, but deactivation kinetics were still faster. Computational simulations using a human ventricular AP model showed that accelerating deactivation rates was sufficient to prolong the AP, but these effects were minimal compared to simply reducing IKr. These are the first data to demonstrate that coexpressing wild type can correct activation and inactivation dysfunction caused by mutations at a critical voltage-sensing residue in Kv11.1. We conclude that some Kv11.1 mutations might accelerate deactivation to cause LQT2 but that the ventricular AP duration is much more sensitive to mutations that decrease IKr. This likely explains why most LQT2 mutations are nonsense or trafficking-deficient. PMID:23546015

  7. Mechanistic basis for type 2 long QT syndrome caused by KCNH2 mutations that disrupt conserved arginine residues in the voltage sensor.

    Science.gov (United States)

    McBride, Christie M; Smith, Ashley M; Smith, Jennifer L; Reloj, Allison R; Velasco, Ellyn J; Powell, Jonathan; Elayi, Claude S; Bartos, Daniel C; Burgess, Don E; Delisle, Brian P

    2013-05-01

    KCNH2 encodes the Kv11.1 channel, which conducts the rapidly activating delayed rectifier K+ current (I Kr) in the heart. KCNH2 mutations cause type 2 long QT syndrome (LQT2), which increases the risk for life-threatening ventricular arrhythmias. LQT2 mutations are predicted to prolong the cardiac action potential (AP) by reducing I Kr during repolarization. Kv11.1 contains several conserved basic amino acids in the fourth transmembrane segment (S4) of the voltage sensor that are important for normal channel trafficking and gating. This study sought to determine the mechanism(s) by which LQT2 mutations at conserved arginine residues in S4 (R531Q, R531W or R534L) alter Kv11.1 function. Western blot analyses of HEK293 cells transiently expressing R531Q, R531W or R534L suggested that only R534L inhibited Kv11.1 trafficking. Voltage-clamping experiments showed that R531Q or R531W dramatically altered Kv11.1 current (I Kv11.1) activation, inactivation, recovery from inactivation and deactivation. Coexpression of wild type (to mimic the patients' genotypes) mostly corrected the changes in I Kv11.1 activation and inactivation, but deactivation kinetics were still faster. Computational simulations using a human ventricular AP model showed that accelerating deactivation rates was sufficient to prolong the AP, but these effects were minimal compared to simply reducing I Kr. These are the first data to demonstrate that coexpressing wild type can correct activation and inactivation dysfunction caused by mutations at a critical voltage-sensing residue in Kv11.1. We conclude that some Kv11.1 mutations might accelerate deactivation to cause LQT2 but that the ventricular AP duration is much more sensitive to mutations that decrease I Kr. This likely explains why most LQT2 mutations are nonsense or trafficking-deficient.

  8. Using mutagenesis to explore conserved residues in the RNA-binding groove of influenza A virus nucleoprotein for antiviral drug development

    Science.gov (United States)

    Liu, Chia-Lin; Hung, Hui-Chen; Lo, Shou-Chen; Chiang, Ching-Hui; Chen, I.-Jung; Hsu, John T.-A.; Hou, Ming-Hon

    2016-02-01

    Nucleoprotein (NP) is the most abundant type of RNA-binding viral protein in influenza A virus-infected cells and is necessary for viral RNA transcription and replication. Recent studies demonstrated that influenza NP is a valid target for antiviral drug development. The surface of the groove, covered with numerous conserved residues between the head and body domains of influenza A NP, plays a crucial role in RNA binding. To explore the mechanism by which NP binds RNA, we performed a series of site-directed mutagenesis in the RNA-binding groove, followed by surface plasmon resonance (SPR), to characterize the interactions between RNA and NP. Furthermore, a role of Y148 in NP stability and NP-RNA binding was evaluated. The aromatic residue of Y148 was found to stack with a nucleotide base. By interrupting the stacking interaction between Y148 and an RNA base, we identified an influenza virus NP inhibitor, (E, E)-1,7-bis(4-hydroxy-3-methoxyphenyl) -1,6-heptadiene-3,5-dione; this inhibitor reduced the NP’s RNA-binding affinity and hindered viral replication. Our findings will be useful for the development of new drugs that disrupt the interaction between RNA and viral NP in the influenza virus.

  9. Insights into the smooth-to-rough transitioning in Mycobacterium bolletii unravels a functional Tyr residue conserved in all mycobacterial MmpL family members.

    Science.gov (United States)

    Bernut, Audrey; Viljoen, Albertus; Dupont, Christian; Sapriel, Guillaume; Blaise, Mickaël; Bouchier, Christiane; Brosch, Roland; de Chastellier, Chantal; Herrmann, Jean-Louis; Kremer, Laurent

    2016-03-01

    In mycobacteria, MmpL proteins represent key components that participate in the biosynthesis of the complex cell envelope. Whole genome analysis of a spontaneous rough morphotype variant of Mycobacterium abscessus subsp. bolletii identified a conserved tyrosine that is crucial for the function of MmpL family proteins. Isogenic smooth (S) and rough (R) variants differed by a single mutation linked to a Y842H substitution in MmpL4a. This mutation caused a deficiency in glycopeptidolipid production/transport in the R variant and a gain in the capacity to produce cords in vitro. In zebrafish, increased virulence of the M. bolletii R variant over the parental S strain was found, involving massive production of serpentine cords, abscess formation and rapid larval death. Importantly, this finding allowed us to demonstrate an essential role of Tyr842 in several different MmpL proteins, including Mycobacterium tuberculosis MmpL3. Structural homology models of MmpL4a and MmpL3 identified two additional critical residues located in the transmembrane regions TM10 and TM4 that are facing each other. We propose that these central residues are part of the proton-motive force that supplies the energy for substrate transport. Hence, we provide important insights into mechanistic/structural aspects of MmpL proteins as lipid transporters and virulence determinants in mycobacteria. © 2015 John Wiley & Sons Ltd.

  10. Cysteine Protease Zymography: Brief Review.

    Science.gov (United States)

    Wilkesman, Jeff

    2017-01-01

    Cysteine proteases play multiple roles in basically all aspects of physiology and development. In plants, they are involved in growth and development and in accumulation and mobilization of storage proteins. Furthermore, they are engaged in signalling pathways and in the response to biotic and abiotic stresses. In animals and also in humans, they are responsible for senescence and apoptosis, prohormone processing, and ECM remodelling. When analyzed by zymography, the enzyme must be renaturated after SDS-PAGE. SDS must be washed out and substituted by Triton X-100. Gels are then further incubated under ideal conditions for activity detection. Cysteine proteases require an acidic pH (5.0-6.0) and a reducing agent, usually DTT. When screening biological samples, there is generally no previous clue on what peptidase class will be present, neither optimal proteolysis conditions are known. Hence, it is necessary to assess several parameters, such as incubation time, pH, temperature, influence of ions or reducing agents, and finally evaluate the inhibition profile. For detection of cysteine peptidase activity, the use of specific inhibitors, such as E-64, can be used to prevent the development of cysteine peptidase activity bands and positively confirm its presence. Here four different protocols to assess cysteine protease activity from different sources are presented.

  11. Role of four conserved aspartic acid residues of EF-loops in the metal ion binding and in the self-assembly of ciliate Euplotes octocarinatus centrin.

    Science.gov (United States)

    Liu, Wen; Duan, Lian; Sun, Tijian; Yang, Binsheng

    2016-12-01

    Ciliate Euplotes octocarinatus centrin (EoCen) is an EF-hand calcium-binding protein closely related to the prototypical calcium sensor protein calmodulin. Four mutants (D37K, D73K, D110K and D146K) were created firstly to elucidate the importance of the first aspartic acid residues (Asp37, Asp73, Asp110 and Asp146) in the beginning of the four EF-loops of EoCen. Aromatic-sensitized Tb 3+ fluorescence indicates that the aspartic acid residues are very important for the metal-binding of EoCen, except for Asp73 (in EF-loop II). Resonance light scattering (RLS) measurements for different metal ions (Ca 2+ and Tb 3+ ) binding proteins suggest that the order of four conserved aspartic acid residues for contributing to the self-assembly of EoCen is Asp37 > Asp146 > Asp110 > Asp73. Cross-linking experiment also exhibits that Asp37 and Asp146 play critical role in the self-assembly of EoCen. Asp37, in site I, which is located in the N-terminal domain, plays the most important role in the metal ion-dependent self-assembly of EoCen, and there is cooperativity between N-terminal and C-terminal domain (especially the site IV). In addition, the dependence of Tb 3+ induced self-assembly of EoCen and the mutants on various factors, including ionic strength and pH, were characterized using RLS. Finally, 2-p-toluidinylnaphthalene-6-sulfonate (TNS) binding, ionic strength and pH control experiments indicate that in the process of EoCen self-assembly, molecular interactions are mediated by both electrostatic and hydrophobic forces, and the hydrophobic interaction has the important status.

  12. Divergent unprotected peptide macrocyclisation by palladium-mediated cysteine arylation.

    Science.gov (United States)

    Rojas, Anthony J; Zhang, Chi; Vinogradova, Ekaterina V; Buchwald, Nathan H; Reilly, John; Pentelute, Bradley L; Buchwald, Stephen L

    2017-06-01

    Macrocyclic peptides are important therapeutic candidates due to their improved physicochemical properties in comparison to their linear counterparts. Here we detail a method for a divergent macrocyclisation of unprotected peptides by crosslinking two cysteine residues with bis-palladium organometallic reagents. These synthetic intermediates are prepared in a single step from commercially available aryl bis-halides. Two bioactive linear peptides with cysteine residues at i , i + 4 and i , i + 7 positions, respectively, were cyclised to introduce a diverse array of aryl and bi-aryl linkers. These two series of macrocyclic peptides displayed similar linker-dependent lipophilicity, phospholipid affinity, and unique volume of distributions. Additionally, one of the bioactive peptides showed target binding affinity that was predominantly affected by the length of the linker. Collectively, this divergent strategy allowed rapid and convenient access to various aryl linkers, enabling the systematic evaluation of the effect of appending unit on the medicinal properties of macrocyclic peptides.

  13. P300/CBP acts as a coactivator to cartilage homeoprotein-1 (Cart1), paired-like homeoprotein, through acetylation of the conserved lysine residue adjacent to the homeodomain.

    Science.gov (United States)

    Iioka, Takashi; Furukawa, Keizo; Yamaguchi, Akira; Shindo, Hiroyuki; Yamashita, Shunichi; Tsukazaki, Tomoo

    2003-08-01

    The paired-like homeoprotein, Cart1, is involved in skeletal development. We describe here that the general coactivator p300/CBP controls the transcription activity of Cart1 through acetylation of a lysine residue that is highly conserved in other homeoproteins. Acetylation of this residue increases the interaction between p300/CBP and Cart1 and enhances its transcriptional activation. Cart1 encodes a paired-like homeoprotein expressed selectively in chondrocyte lineage during embryonic development. Although its target gene remains unknown, gene disruption studies have revealed that Cart1 plays an important role for craniofacial bone formation as well as limb development by cooperating with another homeoprotein, Alx4. In this report, we study the functional involvement of p300/CBP, coactivators with intrinsic histone acetyltransferase (HAT) activity, in the transcriptional control of Cart1. To study the transcription activity of Cart1, a reporter construct containing a putative Cart1 binding site was transiently transfected with the expression vectors of each protein. The interaction between p300/CBP and Cart1 was investigated by glutathione S-transferase (GST) pull-down, yeast two-hybrid, and immunoprecipitation assays. In vitro acetylation assay was performed with the recombinant p300-HAT domain and Cart1 in the presence of acetyl-CoA. p300 and CBP stimulate Cart1-dependent transcription activity, and this transactivation is inhibited by E1A and Tax, oncoproteins that suppress the activity of p300/CBP. Cart1 binds to p300 in vivo and in vitro, and this requires the homeodomain of Cart 1 and N-terminal 139 amino acids of p300. Confocal microscopy analysis shows that Cart1 recruits overexpressed and endogenous p300 to a Cart1-specific subnuclear compartment. Cart1 is acetylated in vivo and sodium butyrate and trichostatin A, histone deacetylase inhibitors, markedly enhance the transcription activity of Cart1. Deletion and mutagenesis analysis identifies the 131st

  14. Familial hypofibrinogenaemia associated with heterozygous substitution of a conserved arginine residue; Bbeta255 Arg-->His (Fibrinogen Merivale).

    Science.gov (United States)

    Maghzal, Ghassan J; Brennan, Stephen O; Fellowes, Andrew P; Spearing, Ruth; George, Peter M

    2003-02-21

    Sequencing of all three fibrinogen genes from an individual with hypofibrinogenaemia led to the identification of two new point mutations in the Bbeta gene. Family studies showed the mutations Bbeta255 Arg-->His (Fibrinogen Merivale) and Bbeta148 Lys-->Asn (Fibrinogen Merivale II) were on different alleles and that only the Bbeta255 Arg-->His mutation segregated with hypofibrinogenaemia. Three simple heterozygotes for this mutation had mean fibrinogen concentrations of 1.4 mg/ml, while heterozygotes for the Bbeta148 Lys-->Asn mutation had normal fibrinogen concentrations. ESI MS analysis of endoproteinase Asp-N digests of Bbeta chains showed that the Bbeta255 Arg-->His substitution was not expressed in plasma, confirming it as the cause of the hypofibrinogenaemia. The Bbeta148 Lys-->Asn chains, on the other hand, were equally expressed with wild-type Bbeta chains in simple heterozygotes. Genotype analysis failed to detect either substitution in 182 healthy controls. Arg(255) is located in the first strand of the five-stranded sheet that forms the main feature of the betaD domain and appears to form an essential H bond with Gly(414). Both the Arg and Gly are absolutely conserved, not only in all known Bbeta chains, but also in all homologous alphaE and gamma chains and in all fibrinogen-related proteins. Protein instability from loss of this contact could easily explain the association of this mutation with hypofibrinogenaemia.

  15. Allicin and derivates are cysteine protease inhibitors with antiparasitic activity.

    Science.gov (United States)

    Waag, Thilo; Gelhaus, Christoph; Rath, Jennifer; Stich, August; Leippe, Matthias; Schirmeister, Tanja

    2010-09-15

    Allicin and derivatives thereof inhibit the CAC1 cysteine proteases falcipain 2, rhodesain, cathepsin B and L in the low micromolar range. The structure-activity relationship revealed that only derivatives with primary carbon atom in vicinity to the thiosulfinate sulfur atom attacked by the active-site Cys residue are active against the target enzymes. Some compounds also show potent antiparasitic activity against Plasmodium falciparum and Trypanosoma brucei brucei. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  16. Arabidopsis ATG4 cysteine proteases specificity toward ATG8 substrates

    Science.gov (United States)

    Park, Eunsook; Woo, Jongchan; Dinesh-Kumar, SP

    2014-01-01

    Macroautophagy (hereafter autophagy) is a regulated intracellular process during which cytoplasmic cargo engulfed by double-membrane autophagosomes is delivered to the vacuole or lysosome for degradation and recycling. Atg8 that is conjugated to phosphatidylethanolamine (PE) during autophagy plays an important role not only in autophagosome biogenesis but also in cargo recruitment. Conjugation of PE to Atg8 requires processing of the C-terminal conserved glycine residue in Atg8 by the Atg4 cysteine protease. The Arabidopsis plant genome contains 9 Atg8 (AtATG8a to AtATG8i) and 2 Atg4 (AtATG4a and AtATG4b) family members. To understand AtATG4’s specificity toward different AtATG8 substrates, we generated a unique synthetic substrate C-AtATG8-ShR (citrine-AtATG8-Renilla luciferase SuperhRLUC). In vitro analyses indicated that AtATG4a is catalytically more active and has broad AtATG8 substrate specificity compared with AtATG4b. Arabidopsis transgenic plants expressing the synthetic substrate C-AtAtg8a-ShR is efficiently processed by endogenous AtATG4s and targeted to the vacuole during nitrogen starvation. These results indicate that the synthetic substrate mimics endogenous AtATG8, and its processing can be monitored in vivo by a bioluminescence resonance energy transfer (BRET) assay. The synthetic Atg8 substrates provide an easy and versatile method to study plant autophagy during different biological processes. PMID:24658121

  17. 35S cystein chlorhydrate preparation

    International Nuclear Information System (INIS)

    Emiliozzi, R.; Pichat, P.; Herbert, M.

    1960-01-01

    35 S cystein chlorhydrate has been prepared with a quantitative yield by electrolytic reduction of 35 S cystin in hydrochloric medium on a vibrating mercury cathode. Reprint of a paper published in Bulletin de la Societe chimique de France, no. 2653, 4. quarter 1959, p. 1544-1545 [fr

  18. Cloning of the cDNA for murine von Willebrand factor and identification of orthologous genes reveals the extent of conservation among diverse species.

    Science.gov (United States)

    Chitta, Mohan S; Duhé, Roy J; Kermode, John C

    2007-05-01

    Interaction of von Willebrand factor (VWF) with circulating platelets promotes hemostasis when a blood vessel is injured. The A1 domain of VWF is responsible for the initial interaction with platelets and is well conserved among species. Knowledge of the cDNA and genomic DNA sequences for human VWF allowed us to predict the cDNA sequence for murine VWF in silico and amplify its entire coding region by RT-PCR. The murine VWF cDNA has an open reading frame of 8,442 bp, encoding a protein of 2,813 amino acid residues with 83% identity to human pre-pro-VWF. The same strategy was used to predict in silico the cDNA sequence for the ortholog of VWF in a further six species. Many of these predictions diverged substantially from the putative Reference Sequences derived by ab initio methods. Our predicted sequences indicated that the VWF gene has a conserved structure of 52 exons in all seven mammalian species examined, as well as in the chicken. There is a minor structural variation in the pufferfish Takifugu rubripes insofar as the VWF gene in this species has 53 exons. Comparison of the translated amino acid sequences also revealed a high degree of conservation. In particular, the cysteine residues are conserved precisely throughout both the pro-peptide and the mature VWF sequence in all species, with a minor exception in the pufferfish VWF ortholog where two adjacent cysteine residues are omitted. The marked conservation of cysteine residues emphasizes the importance of the intricate pattern of disulfide bonds in governing the structure of pro-VWF and regulating the function of the mature VWF protein. It should also be emphasized that many of the conserved features of the VWF gene and protein were obscured when the comparison among species was based on the putative Reference Sequences instead of our predicted cDNA sequences.

  19. The Highly Conserved Proline at Position 438 in Pseudorabies Virus gH Is Important for Regulation of Membrane Fusion

    OpenAIRE

    Schröter, Christina; Klupp, Barbara G.; Fuchs, Walter; Gerhard, Marika; Backovic, Marija; Rey, Felix A.; Mettenleiter, Thomas C.

    2014-01-01

    Membrane fusion in herpesviruses requires viral glycoproteins (g) gB and gH/gL. While gB is considered the actual fusion protein but is nonfusogenic per se, the function of gH/gL remains enigmatic. Crystal structures for different gH homologs are strikingly similar despite only moderate amino acid sequence conservation. A highly conserved sequence motif comprises the residues serine-proline-cysteine corresponding to positions 437 to 439 in pseudorabies virus (PrV) gH. The PrV-gH structure sho...

  20. Inhibition of transcription factor NF-kappaB signaling proteins IKKbeta and p65 through specific cysteine residues by epoxyquinone A monomer: correlation with its anti-cancer cell growth activity.

    Science.gov (United States)

    Liang, Mei-Chih; Bardhan, Sujata; Pace, Emily A; Rosman, Diana; Beutler, John A; Porco, John A; Gilmore, Thomas D

    2006-02-28

    Transcription factor NF-kappaB is constitutively active in many human chronic inflammatory diseases and cancers. Epoxyquinone A monomer (EqM), a synthetic derivative of the natural product epoxyquinol A, has previously been shown to be a potent inhibitor of tumor necrosis factor-alpha (TNF-alpha)-induced activation of NF-kappaB, but the mechanism by which EqM inhibits NF-kappaB activation was not known. In this report, we show that EqM blocks activation of NF-kappaB by inhibiting two molecular targets: IkappaB kinase IKKbeta and NF-kappaB subunit p65. EqM inhibits TNF-alpha-induced IkappaBalpha phosphorylation and degradation by targeting IKKbeta, and an alanine substitution for Cys179 in the activation loop of IKKbeta makes it resistant to EqM-mediated inhibition. EqM also directly inhibits DNA binding by p65, but not p50; moreover, replacement of Cys38 in p65 with Ser abolishes EqM-mediated inhibition of DNA binding. Pretreatment of cells with reducing agent dithiothreitol dose-dependently reduces EqM-mediated inhibition of NF-kappaB, further suggesting that EqM directly modifies the thiol group of Cys residues in protein targets. Modifications of the exocyclic alkene of EqM substantially reduce EqM's ability to inhibit NF-kappaB activation. In the human SUDHL-4 lymphoma cell line, EqM inhibits both proliferation and NF-kappaB DNA binding, and activates caspase-3 activity. EqM also effectively inhibits the growth of human leukemia, kidney, and colon cancer cell lines in the NCI's tumor cell panel. Among six colon cancer cell lines, those with low amounts of constitutive NF-kappaB DNA-binding activity are generally more sensitive to growth inhibition by EqM. Taken together, these results suggest that EqM inhibits growth and induces cell death in tumor cells through a mechanism that involves inhibition of NF-kappaB activity at multiple steps in the signaling pathway.

  1. Cysteine regulation of protein function--as exemplified by NMDA-receptor modulation.

    Science.gov (United States)

    Lipton, Stuart A; Choi, Yun-Beom; Takahashi, Hiroto; Zhang, Dongxian; Li, Weizhong; Godzik, Adam; Bankston, Laurie A

    2002-09-01

    Until recently cysteine residues, especially those located extracellularly, were thought to be important for metal coordination, catalysis and protein structure by forming disulfide bonds - but they were not thought to regulate protein function. However, this is not the case. Crucial cysteine residues can be involved in modulation of protein activity and signaling events via other reactions of their thiol (sulfhydryl; -SH) groups. These reactions can take several forms, such as redox events (chemical reduction or oxidation), chelation of transition metals (chiefly Zn(2+), Mn(2+) and Cu(2+)) or S-nitrosylation [the catalyzed transfer of a nitric oxide (NO) group to a thiol group]. In several cases, these disparate reactions can compete with one another for the same thiol group on a single cysteine residue, forming a molecular switch composed of a latticework of possible redox, NO or Zn(2+) modifications to control protein function. Thiol-mediated regulation of protein function can also involve reactions of cysteine residues that affect ligand binding allosterically. This article reviews the basis for these molecular cysteine switches, drawing on the NMDA receptor as an exemplary protein, and proposes a molecular model for the action of S-nitrosylation based on recently derived crystal structures.

  2. Evolutionary conservativeness of electric field in the Cu,Zn superoxide dismutase active site. Evidence for co-ordinated mutation of charged amino acid residues.

    Science.gov (United States)

    Desideri, A; Falconi, M; Polticelli, F; Bolognesi, M; Djinovic, K; Rotilio, G

    1992-01-05

    Equipotential lines were calculated, using the Poisson-Boltzmann equation, for six Cu,Zn superoxide dismutases with different protein electric charge and various degrees of sequence homology, namely those from ox, pig, sheep, yeast, and the isoenzymes A and B from the amphibian Xenopus laevis. The three-dimensional structures of the porcine and ovine superoxide dismutases were obtained by molecular modelling reconstruction using the structure of the highly homologous bovine enzyme as a template. The three-dimensional structure of the evolutionary distant yeast Cu,Zn superoxide dismutase was recently resolved by us, while computer-modelled structures are available for X. laevis isoenzymes. The six proteins display large differences in the net protein charge and distribution of electrically charged surface residues but the trend of the equipotential lines in the proximity of the active sites was found to be constant in all cases. These results are in line with the very similar catlytic rate constants experimentally measured for the corresponding enzyme activities. This analysis shows that electrostatic guidance for the enzyme-substrate interaction in Cu,Zn superoxide dismutases is related to a spatial distribution of charges, arranged so as to maintain, in the area surrounding the active sites, an identical electrostatic potential distribution, which is conserved in the evolution of this protein family.

  3. Activation of human acid sphingomyelinase through modification or deletion of C-terminal cysteine.

    Science.gov (United States)

    Qiu, Huawei; Edmunds, Tim; Baker-Malcolm, Jennifer; Karey, Kenneth P; Estes, Scott; Schwarz, Cordula; Hughes, Heather; Van Patten, Scott M

    2003-08-29

    One form of Niemann-Pick disease is caused by a deficiency in the enzymatic activity of acid sphingomyelinase. During efforts to develop an enzyme replacement therapy based on a recombinant form of human acid sphingomyelinase (rhASM), purified preparations of the recombinant enzyme were found to have substantially increased specific activity if cell harvest media were stored for several weeks at -20 degrees C prior to purification. This increase in activity was found to correlate with the loss of the single free thiol on rhASM, suggesting the involvement of a cysteine residue. It was demonstrated that a variety of chemical modifications of the free cysteine on rhASM all result in substantial activation of the enzyme, and the modified cysteine responsible for this activation was shown to be the C-terminal residue (Cys629). Activation was also achieved by copper-promoted dimerization of rhASM (via cysteine) and by C-terminal truncation using carboxypeptidase Y. The role of the C-terminal cysteine in activation was confirmed by creating mutant forms of rhASM in which this residue was either deleted or replaced by a serine, with both forms having substantially higher specific activity than wild-type rhASM. These results indicate that purified rhASM can be activated in vitro by loss of the free thiol on the C-terminal cysteine via chemical modification, dimerization, or deletion of this amino acid residue. This method of activation is similar to the cysteine switch mechanism described previously for matrix metalloproteinases and could represent a means of posttranslational regulation of ASM activity in vivo.

  4. The Cysteine S-Alkylation Reaction as a Synthetic Method to Covalently Modify Peptide Sequences.

    Science.gov (United States)

    Calce, Enrica; De Luca, Stefania

    2017-01-05

    Synthetic methodologies to chemically modify peptide molecules have long been investigated for their impact in the field of chemical biology. They allow the introduction of biochemical probes useful for studying protein functions, for manipulating peptides with therapeutic potential, and for structure-activity relationship investigations. The commonly used approach was the derivatization of an amino acid side chain. In this regard, the cysteine, for its unique reactivity, has been widely employed as the substrate for such modifications. Herein, we report on methodologies developed to modify the cysteine thiol group through the S-alkylation reaction. Some procedures perform the alkylation of cysteine derivatives, in order to prepare building blocks to be used during the peptide synthesis, whilst some others selectively modify peptide sequences containing a cysteine residue with a free thiol group, both in solution and in the solid phase. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Characterization of the gene encoding serine acetyltransferase, a regulated enzyme of cysteine biosynthesis from the protist parasites Entamoeba histolytica and Entamoeba dispar. Regulation and possible function of the cysteine biosynthetic pathway in Entamoeba.

    Science.gov (United States)

    Nozaki, T; Asai, T; Sanchez, L B; Kobayashi, S; Nakazawa, M; Takeuchi, T

    1999-11-05

    The enteric protist parasites Entamoeba histolytica and Entamoeba dispar possess a cysteine biosynthetic pathway, unlike their mammalian host, and are capable of de novo production of L-cysteine. We cloned and characterized cDNAs that encode the regulated enzyme serine acetyltransferase (SAT) in this pathway from these amoebae by genetic complementation of a cysteine-auxotrophic Escherichia coli strain with the amoebic cDNA libraries. The deduced amino acid sequences of the amoebic SATs exhibited, within the most conserved region, 36-52% identities with the bacterial and plant SATs. The amoebic SATs contain a unique insertion of eight amino acids, also found in the corresponding region of a plasmid-encoded SAT from Synechococcus sp., which showed the highest overall identities to the amoebic SATs. Phylogenetic reconstruction also revealed a close kinship of the amoebic SATs with cyanobacterial SATs. Biochemical characterization of the recombinant E. histolytica SAT revealed several enzymatic features that distinguished the amoebic enzyme from the bacterial and plant enzymes: 1) inhibition by L-cysteine in a competitive manner with L-serine; 2) inhibition by L-cystine; and 3) no association with cysteine synthase. Genetically engineered amoeba strains that overproduced cysteine synthase and SAT were created. The cysteine synthase-overproducing amoebae had a higher level of cysteine synthase activity and total thiol content and revealed increased resistance to hydrogen peroxide. These results indicate that the cysteine biosynthetic pathway plays an important role in antioxidative defense of these enteric parasites.

  6. pH-induced conformational change of IscU at low pH correlates with protonation/deprotonation of two conserved histidine residues.

    Science.gov (United States)

    Dai, Ziqi; Kim, Jin Hae; Tonelli, Marco; Ali, Ibrahim K; Markley, John L

    2014-08-19

    IscU, the scaffold protein for the major iron-sulfur cluster biosynthesis pathway in microorganisms and mitochondria (ISC pathway), plays important roles in the formation of [2Fe-2S] and [4Fe-4S] clusters and their delivery to acceptor apo-proteins. Our laboratory has shown that IscU populates two distinct, functionally relevant conformational states, a more structured state (S) and a more dynamic state (D), that differ by cis/trans isomerizations about two peptidyl-prolyl peptide bonds [Kim, J. H., Tonelli, M., and Markley, J. L. (2012) Proc. Natl. Acad. Sci. U.S.A., 109, 454-459. Dai Z., Tonelli, M., and Markley, J. L. (2012) Biochemistry, 51, 9595-9602. Cai, K., Frederick, R. O., Kim, J. H., Reinen, N. M., Tonelli, M., and Markley, J. L. (2013) J. Biol. Chem., 288, 28755-28770]. Here, we report our findings on the pH dependence of the D ⇄ S equilibrium for Escherichia coli IscU in which the D-state is stabilized at low and high pH values. We show that the lower limb of the pH dependence curve results from differences in the pKa values of two conserved histidine residues (His10 and His105) in the two states. The net proton affinity of His10 is about 50 times higher and that of His105 is 13 times higher in the D-state than in the S-state. The origin of the high limb of the D ⇄ S pH dependence remains to be determined. These results show that changes in proton inventory need to be taken into account in the steps in iron-sulfur cluster assembly and transfer that involve transitions of IscU between its S- and D-states.

  7. Structural and functional studies of the biotin protein ligase from Aquifex aeolicus reveal a critical role for a conserved residue in target specificity.

    Science.gov (United States)

    Tron, Cecile M; McNae, Iain W; Nutley, Margaret; Clarke, David J; Cooper, Alan; Walkinshaw, Malcolm D; Baxter, Robert L; Campopiano, Dominic J

    2009-03-20

    Biotin protein ligase (BPL; EC 6.3.4.15) catalyses the formation of biotinyl-5'-AMP from biotin and ATP, and the succeeding biotinylation of the biotin carboxyl carrier protein. We describe the crystal structures, at 2.4 A resolution, of the class I BPL from the hyperthermophilic bacteria Aquifex aeolicus (AaBPL) in its ligand-free form and in complex with biotin and ATP. The solvent-exposed beta- and gamma-phosphates of ATP are located in the inter-subunit cavity formed by the N- and C-terminal domains. The Arg40 residue from the conserved GXGRXG motif is shown to interact with the carboxyl group of biotin and to stabilise the alpha- and beta-phosphates of the nucleotide. The structure of the mutant AaBPL R40G in both the ligand-free and biotin-bound forms reveals that the mutated loop has collapsed, thus hindering ATP binding. Isothermal titration calorimetry indicated that the presence of biotin is not required for ATP binding to wild-type AaBPL in the absence of Mg(2+), and the binding of biotin and ATP has been determined to occur via a random but cooperative process. The affinity for biotin is relatively unaffected by the R40G mutation. In contrast, the thermodynamic data indicate that binding of ATP to AaBPL R40G is very weak in the absence or in the presence of biotin. The AaBPL R40G mutant remains catalytically active but shows poor substrate specificity; mass spectrometry and Western blot studies revealed that the mutant biotinylates both the target A. aeolicus BCCPDelta67 fragment and BSA, and is subject to self-biotinylation.

  8. The valine and lysine residues in the conserved FxVTxK motif are important for the function of phylogenetically distant plant cellulose synthases

    Energy Technology Data Exchange (ETDEWEB)

    Slabaugh, Erin; Scavuzzo-Duggan, Tess; Chaves, Arielle; Wilson, Liza; Wilson, Carmen; Davis, Jonathan K.; Cosgrove, Daniel J.; Anderson, Charles T.; Roberts, Alison W.; Haigler, Candace H.

    2015-12-08

    Cellulose synthases (CESAs) synthesize the β-1,4-glucan chains that coalesce to form cellulose microfibrils in plant cell walls. In addition to a large cytosolic (catalytic) domain, CESAs have eight predicted transmembrane helices (TMHs). However, analogous to the structure of BcsA, a bacterial CESA, predicted TMH5 in CESA may instead be an interfacial helix. This would place the conserved FxVTxK motif in the plant cell cytosol where it could function as a substrate-gating loop as occurs in BcsA. To define the functional importance of the CESA region containing FxVTxK, we tested five parallel mutations in Arabidopsis thaliana CESA1 and Physcomitrella patens CESA5 in complementation assays of the relevant cesa mutants. In both organisms, the substitution of the valine or lysine residues in FxVTxK severely affected CESA function. In Arabidopsis roots, both changes were correlated with lower cellulose anisotropy, as revealed by Pontamine Fast Scarlet. Analysis of hypocotyl inner cell wall layers by atomic force microscopy showed that two altered versions of Atcesa1 could rescue cell wall phenotypes observed in the mutant background line. Overall, the data show that the FxVTxK motif is functionally important in two phylogenetically distant plant CESAs. The results show that Physcomitrella provides an efficient model for assessing the effects of engineered CESA mutations affecting primary cell wall synthesis and that diverse testing systems can lead to nuanced insights into CESA structure–function relationships. Although CESA membrane topology needs to be experimentally determined, the results support the possibility that the FxVTxK region functions similarly in CESA and BcsA.

  9. CMD: A Database to Store the Bonding States of Cysteine Motifs with Secondary Structures

    Directory of Open Access Journals (Sweden)

    Hamed Bostan

    2012-01-01

    Full Text Available Computational approaches to the disulphide bonding state and its connectivity pattern prediction are based on various descriptors. One descriptor is the amino acid sequence motifs flanking the cysteine residue motifs. Despite the existence of disulphide bonding information in many databases and applications, there is no complete reference and motif query available at the moment. Cysteine motif database (CMD is the first online resource that stores all cysteine residues, their flanking motifs with their secondary structure, and propensity values assignment derived from the laboratory data. We extracted more than 3 million cysteine motifs from PDB and UniProt data, annotated with secondary structure assignment, propensity value assignment, and frequency of occurrence and coefficiency of their bonding status. Removal of redundancies generated 15875 unique flanking motifs that are always bonded and 41577 unique patterns that are always nonbonded. Queries are based on the protein ID, FASTA sequence, sequence motif, and secondary structure individually or in batch format using the provided APIs that allow remote users to query our database via third party software and/or high throughput screening/querying. The CMD offers extensive information about the bonded, free cysteine residues, and their motifs that allows in-depth characterization of the sequence motif composition.

  10. Crystal Structure of a Hidden Protein, YcaC, a Putative Cysteine Hydrolase from Pseudomonas aeruginosa, with and without an Acrylamide Adduct

    Directory of Open Access Journals (Sweden)

    Morten K. Grøftehauge

    2015-07-01

    Full Text Available As part of the ongoing effort to functionally and structurally characterize virulence factors in the opportunistic pathogen Pseudomonas aeruginosa, we determined the crystal structure of YcaC co-purified with the target protein at resolutions of 2.34 and 2.56 Å without a priori knowledge of the protein identity or experimental phases. The three-dimensional structure of YcaC adopts a well-known cysteine hydrolase fold with the putative active site residues conserved. The active site cysteine is covalently bound to propionamide in one crystal form, whereas the second form contains an S-mercaptocysteine. The precise biological function of YcaC is unknown; however, related prokaryotic proteins have functions in antibacterial resistance, siderophore production and NADH biosynthesis. Here, we show that YcaC is exceptionally well conserved across both bacterial and fungal species despite being non-ubiquitous. This suggests that whilst YcaC may not be part of an integral pathway, the function could confer a significant evolutionary advantage to microbial life.

  11. Redox Activation of the Universally Conserved ATPase YchF by Thioredoxin 1.

    Science.gov (United States)

    Hannemann, Liya; Suppanz, Ida; Ba, Qiaorui; MacInnes, Katherine; Drepper, Friedel; Warscheid, Bettina; Koch, Hans-Georg

    2016-01-20

    YchF/Ola1 are unconventional members of the universally conserved GTPase family because they preferentially hydrolyze ATP rather than GTP. These ATPases have been associated with various cellular processes and pathologies, including DNA repair, tumorigenesis, and apoptosis. In particular, a possible role in regulating the oxidative stress response has been suggested for both bacterial and human YchF/Ola1. In this study, we analyzed how YchF responds to oxidative stress and how it potentially regulates the antioxidant response. Our data identify a redox-regulated monomer-dimer equilibrium of YchF as a key event in the functional cycle of YchF. Upon oxidative stress, the oxidation of a conserved and surface-exposed cysteine residue promotes YchF dimerization, which is accompanied by inhibition of the ATPase activity. No dimers were observed in a YchF mutant lacking this cysteine. In vitro, the YchF dimer is dissociated by thioredoxin 1 (TrxA) and this stimulates the ATPase activity. The physiological significance of the YchF-thioredoxin 1 interaction was demonstrated by in vivo cross-linking, which validated this interaction in living cells. This approach also revealed that both the ATPase domain and the helical domain of YchF are in contact with TrxA. YchF/Ola1 are the first redox-regulated members of the universally conserved GTPase family and are inactivated by oxidation of a conserved cysteine residue within the nucleotide-binding motif. Our data provide novel insights into the regulation of the so far ill-defined YchF/Ola1 family of proteins and stipulate their role as negative regulators of the oxidative stress response.

  12. Mechanisms of Mitochondrial Holocytochrome c Synthase and the Key Roles Played by Cysteines and Histidine of the Heme Attachment Site, Cys-XX-Cys-His*

    Science.gov (United States)

    Babbitt, Shalon E.; San Francisco, Brian; Mendez, Deanna L.; Lukat-Rodgers, Gudrun S.; Rodgers, Kenton R.; Bretsnyder, Eric C.; Kranz, Robert G.

    2014-01-01

    Mitochondrial cytochrome c assembly requires the covalent attachment of heme by thioether bonds between heme vinyl groups and a conserved CXXCH motif of cytochrome c/c1. The enzyme holocytochrome c synthase (HCCS) binds heme and apocytochrome c substrate to catalyze this attachment, subsequently releasing holocytochrome c for proper folding to its native structure. We address mechanisms of assembly using a functional Escherichia coli recombinant system expressing human HCCS. Human cytochrome c variants with individual cysteine, histidine, double cysteine, and triple cysteine/histidine substitutions (of CXXCH) were co-purified with HCCS. Single and double mutants form a complex with HCCS but not the triple mutant. Resonance Raman and UV-visible spectroscopy support the proposal that heme puckering induced by both thioether bonds facilitate release of holocytochrome c from the complex. His-19 (of CXXCH) supplies the second axial ligand to heme in the complex, the first axial ligand was previously shown to be from HCCS residue His-154. Substitutions of His-19 in cytochrome c to seven other residues (Gly, Ala, Met, Arg, Lys, Cys, and Tyr) were used with various approaches to establish other roles played by His-19. Three roles for His-19 in HCCS-mediated assembly are suggested: (i) to provide the second axial ligand to the heme iron in preparation for covalent attachment; (ii) to spatially position the two cysteinyl sulfurs adjacent to the two heme vinyl groups for thioether formation; and (iii) to aid in release of the holocytochrome c from the HCCS active site. Only H19M is able to carry out these three roles, albeit at lower efficiencies than the natural His-19. PMID:25170082

  13. Mechanisms of mitochondrial holocytochrome c synthase and the key roles played by cysteines and histidine of the heme attachment site, Cys-XX-Cys-His.

    Science.gov (United States)

    Babbitt, Shalon E; San Francisco, Brian; Mendez, Deanna L; Lukat-Rodgers, Gudrun S; Rodgers, Kenton R; Bretsnyder, Eric C; Kranz, Robert G

    2014-10-17

    Mitochondrial cytochrome c assembly requires the covalent attachment of heme by thioether bonds between heme vinyl groups and a conserved CXXCH motif of cytochrome c/c1. The enzyme holocytochrome c synthase (HCCS) binds heme and apocytochrome c substrate to catalyze this attachment, subsequently releasing holocytochrome c for proper folding to its native structure. We address mechanisms of assembly using a functional Escherichia coli recombinant system expressing human HCCS. Human cytochrome c variants with individual cysteine, histidine, double cysteine, and triple cysteine/histidine substitutions (of CXXCH) were co-purified with HCCS. Single and double mutants form a complex with HCCS but not the triple mutant. Resonance Raman and UV-visible spectroscopy support the proposal that heme puckering induced by both thioether bonds facilitate release of holocytochrome c from the complex. His-19 (of CXXCH) supplies the second axial ligand to heme in the complex, the first axial ligand was previously shown to be from HCCS residue His-154. Substitutions of His-19 in cytochrome c to seven other residues (Gly, Ala, Met, Arg, Lys, Cys, and Tyr) were used with various approaches to establish other roles played by His-19. Three roles for His-19 in HCCS-mediated assembly are suggested: (i) to provide the second axial ligand to the heme iron in preparation for covalent attachment; (ii) to spatially position the two cysteinyl sulfurs adjacent to the two heme vinyl groups for thioether formation; and (iii) to aid in release of the holocytochrome c from the HCCS active site. Only H19M is able to carry out these three roles, albeit at lower efficiencies than the natural His-19. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Multimerization of GPIHBP1 and Familial Chylomicronemia from a Serine-to-Cysteine Substitution in GPIHBP1's Ly6 Domain

    DEFF Research Database (Denmark)

    Plengpanich, Wanee; Young, Stephen G; Khovidhunkit, Weerapan

    2014-01-01

    -fingered structure containing 10 cysteines and a conserved pattern of disulfide bond formation. Here, we report a patient with severe hypertriglyceridemia who was homozygous for a GPIHBP1 point mutation that converted a serine in GPIHBP1's Ly6 domain (Ser-107) to a cysteine. Two hypertriglyceridemic siblings were...

  15. A cysteine protease (cathepsin Z) from disk abalone, Haliotis discus discus: Genomic characterization and transcriptional profiling during bacterial infections.

    Science.gov (United States)

    Godahewa, G I; Perera, N C N; Lee, Sukkyoung; Kim, Myoung-Jin; Lee, Jehee

    2017-09-05

    Cathepsin Z (CTSZ) is lysosomal cysteine protease of the papain superfamily. It participates in the host immune defense via phagocytosis, signal transduction, cell-cell communication, proliferation, and migration of immune cells such as monocytes, macrophages, and dendritic cells. Hence, CTSZ is also acknowledged as an acute-phase protein in host immunity. In this study, we sought to identify the CTSZ homolog from disk abalone (AbCTSZ) and characterize it at the molecular, genomic, and transcriptional levels. AbCTSZ encodes a protein with 318 amino acids and a molecular mass of 36kDa. The structure of AbCTSZ reveals amino acid sequences that are characteristic of the signal sequence, pro-peptide, peptidase-C1 papain family cysteine protease domain, mini-loop, HIP motif, N-linked glycosylation sites, active sites, and conserved Cys residues. A pairwise comparison revealed that AbCTSZ shared the highest amino acid homology with its molluscan counterpart from Crassostrea gigas. A multiple alignment analysis revealed the conservation of functionally crucial elements of AbCTSZ, and a phylogenetic study further confirmed a proximal evolutionary relationship with its invertebrate counterparts. Further, an analysis of AbCTSZ genomic structure revealed seven exons separated by six introns, which differs from that of its vertebrate counterparts. Quantitative real time PCR (qPCR) detected the transcripts of AbCTSZ in early developmental stages and in eight different tissues. Higher levels of AbCTSZ transcripts were found in trochophore, gill, and hemocytes, highlighting its importance in the early development and immunity of disk abalone. In addition, we found that viable bacteria (Vibrio parahaemolyticus and Listeria monocytogenes) and bacterial lipopolysaccharides significantly modulated AbCTSZ transcription. Collectively, these lines of evidences suggest that AbCTSZ plays an indispensable role in the innate immunity of disk abalone. Copyright © 2017. Published by Elsevier

  16. [Inhibition by cysteine of the carbohydrate-binding activity of lectins from Ricinus communis, Canavalia ensiformis and Euonymus europaeus].

    Science.gov (United States)

    Dvorkin, V M

    1985-10-01

    Precipitation induced by different lectins has been studied in the presence of some aminoacids. It was shown that precipitates formed by lectins from Ricinus communis (RCA1), Canavalia ensiformis (Con A), Euonymus europaeus (Eel) in the presence of appropriate carbohydrate-containing molecules disappeared after cysteine addition, like after addition of specific carbohydrate precipitation inhibitors. It is assumed that cysteine residues of RCA1, Con A and Eel lectins are essential for their carbohydrate binding activity.

  17. Structural and functional importance of transmembrane domain 3 (TM3) in the aspartate:alanine antiporter AspT: topology and function of the residues of TM3 and oligomerization of AspT.

    Science.gov (United States)

    Nanatani, Kei; Maloney, Peter C; Abe, Keietsu

    2009-04-01

    AspT, the aspartate:alanine antiporter of Tetragenococcus halophilus, a membrane protein of 543 amino acids with 10 putative transmembrane (TM) helices, is the prototype of the aspartate:alanine exchanger (AAE) family of transporters. Because TM3 (isoleucine 64 to methionine 85) has many amino acid residues that are conserved among members of the AAE family and because TM3 contains two charged residues and four polar residues, it is thought to be located near (or to form part of) the substrate translocation pathway that includes the binding site for the substrates. To elucidate the role of TM3 in the transport process, we carried out cysteine-scanning mutagenesis. The substitutions of tyrosine 75 and serine 84 had the strongest inhibitory effects on transport (initial rates of l-aspartate transport were below 15% of the rate for cysteine-less AspT). Considerable but less-marked effects were observed upon the replacement of methionine 70, phenylalanine 71, glycine 74, arginine 76, serine 83, and methionine 85 (initial rates between 15% and 30% of the rate for cysteine-less AspT). Introduced cysteine residues at the cytoplasmic half of TM3 could be labeled with Oregon green maleimide (OGM), whereas cysteines close to the periplasmic half (residues 64 to 75) were not labeled. These results suggest that TM3 has a hydrophobic core on the periplasmic half and that hydrophilic residues on the cytoplasmic half of TM3 participate in the formation of an aqueous cavity in membranes. Furthermore, the presence of l-aspartate protected the cysteine introduced at glycine 62 against a reaction with OGM. In contrast, l-aspartate stimulated the reactivity of the cysteine introduced at proline 79 with OGM. These results demonstrate that TM3 undergoes l-aspartate-induced conformational alterations. In addition, nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses and a glutaraldehyde cross-linking assay suggest that functional AspT forms homo-oligomers as a

  18. Structural and Functional Importance of Transmembrane Domain 3 (TM3) in the Aspartate:Alanine Antiporter AspT: Topology and Function of the Residues of TM3 and Oligomerization of AspT▿

    Science.gov (United States)

    Nanatani, Kei; Maloney, Peter C.; Abe, Keietsu

    2009-01-01

    AspT, the aspartate:alanine antiporter of Tetragenococcus halophilus, a membrane protein of 543 amino acids with 10 putative transmembrane (TM) helices, is the prototype of the aspartate:alanine exchanger (AAE) family of transporters. Because TM3 (isoleucine 64 to methionine 85) has many amino acid residues that are conserved among members of the AAE family and because TM3 contains two charged residues and four polar residues, it is thought to be located near (or to form part of) the substrate translocation pathway that includes the binding site for the substrates. To elucidate the role of TM3 in the transport process, we carried out cysteine-scanning mutagenesis. The substitutions of tyrosine 75 and serine 84 had the strongest inhibitory effects on transport (initial rates of l-aspartate transport were below 15% of the rate for cysteine-less AspT). Considerable but less-marked effects were observed upon the replacement of methionine 70, phenylalanine 71, glycine 74, arginine 76, serine 83, and methionine 85 (initial rates between 15% and 30% of the rate for cysteine-less AspT). Introduced cysteine residues at the cytoplasmic half of TM3 could be labeled with Oregon green maleimide (OGM), whereas cysteines close to the periplasmic half (residues 64 to 75) were not labeled. These results suggest that TM3 has a hydrophobic core on the periplasmic half and that hydrophilic residues on the cytoplasmic half of TM3 participate in the formation of an aqueous cavity in membranes. Furthermore, the presence of l-aspartate protected the cysteine introduced at glycine 62 against a reaction with OGM. In contrast, l-aspartate stimulated the reactivity of the cysteine introduced at proline 79 with OGM. These results demonstrate that TM3 undergoes l-aspartate-induced conformational alterations. In addition, nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses and a glutaraldehyde cross-linking assay suggest that functional AspT forms homo-oligomers as a

  19. Protein cysteine oxidation in redox signaling

    DEFF Research Database (Denmark)

    Forman, Henry Jay; Davies, Michael J; Krämer, Anna C

    2017-01-01

    Oxidation of critical signaling protein cysteines regulated by H2O2 has been considered to involve sulfenic acid (RSOH) formation. RSOH may subsequently form either a sulfenyl amide (RSNHR') with a neighboring amide, or a mixed disulfide (RSSR') with another protein cysteine or glutathione. Previ...

  20. Yeast genes involved in regulating cysteine uptake affect production of hydrogen sulfide from cysteine during fermentation.

    Science.gov (United States)

    Huang, Chien-Wei; Walker, Michelle E; Fedrizzi, Bruno; Gardner, Richard C; Jiranek, Vladimir

    2017-08-01

    An early burst of hydrogen sulfide (H2S) produced by Saccharomyces cerevisiae during fermentation could increase varietal thiols and therefore enhance desirable tropical aromas in varieties such as Sauvignon Blanc. Here we attempted to identify genes affecting H2S formation from cysteine by screening yeast deletion libraries via a colony colour assay on media resembling grape juice. Both Δlst4 and Δlst7 formed lighter coloured colonies and produced significantly less H2S than the wild type on high concentrations of cysteine, likely because they are unable to take up cysteine efficiently. We then examined the nine known cysteine permeases and found that deletion of AGP1, GNP1 and MUP1 led to reduced production of H2S from cysteine. We further showed that deleting genes involved in the SPS-sensing pathway such as STP1 and DAL81 also reduced H2S from cysteine. Together, this study indirectly confirms that Agp1p, Gnp1p and Mup1p are the major cysteine permeases and that they are regulated by the SPS-sensing and target of rapamycin pathways under the grape juice-like, cysteine-supplemented, fermentation conditions. The findings highlight that cysteine transportation could be a limiting factor for yeast to generate H2S from cysteine, and therefore selecting wine yeasts without defects in cysteine uptake could maximise thiol production potential. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Long-term impact of reduced tillage and residue management on soil carbon stabilization: Implications for conservation agriculture on contrasting soils

    OpenAIRE

    Chivenge, P.P.; Murwira, H.K.; Giller, K.E.; Mapfumo, P.; Six, J.

    2007-01-01

    Metadata only record The long-term effects of tillage system and residue management on soil organic carbon stabilization are studied in two tropical soils in Zimbabwe, a red clay and a sandy soil. The four tillage systems evaluated were conventional tillage (CT), mulch ripping (MR), clean ripping (CR) and tied ridging (TR). Soil organic carbon (SOC) content was measured for each size fraction as well as total SOC. Based on the findings, the authors conclude that residue management - mainta...

  2. Evidence for cysteine sulfinate as a neurotransmitter

    International Nuclear Information System (INIS)

    Recasens, M.; Varga, V.; Nanopoulos, D.; Saadoun, F.; Vincendon, G.; Benavides, J.

    1982-01-01

    The Na + -independent binding of L-[ 3 H]cysteine sulfinate and L-[ 3 H]cysteine sulfinate uptake were investigated in rat brain membranes and vesicles. Specific binding of L-[ 3 H]cysteine sulfinate was saturable and occurred by a single high affinity process with a Ksub(b) of 100 nM +- 9 and a capacity (Bsub(max)) of 2.4 +- 0.22 pmol/mg protein. The regional distribution of the binding of L-[ 3 H]cysteine sulfinate in the brain was found to be heterogeneous. The rate of L-[ 3 H]cysteine sulfinate uptake shows a biphasic dependence on the concentration of L-cysteine sulfinate, corresponding to a high affinity (27.2 μM) and a low affinity (398 μM) transport system. The maximum L-[ 3 H]cysteine sulfinate uptake is reached at 2min and the uptake increases as a function of the sodium concentration. Chloride and potassium ions stimulate the uptake. (Auth.)

  3. Identification, classification and expression pattern analysis of sugarcane cysteine proteinases

    Directory of Open Access Journals (Sweden)

    Gustavo Coelho Correa

    2001-12-01

    Full Text Available Cysteine proteases are peptidyl hydrolyses dependent on a cysteine residue at the active center. The physical and chemical properties of cysteine proteases have been extensively characterized, but their precise biological functions have not yet been completely understood, although it is known that they are involved in a number of events such as protein turnover, cancer, germination, programmed cell death and senescence. Protein sequences from different cysteine proteinases, classified as members of the E.C.3.4.22 sub-sub-class, were used to perform a T-BLAST-n search on the Brazilian Sugarcane Expressed Sequence Tags project (SUCEST data bank. Sequence homology was found with 76 cluster sequences that corresponded to possible cysteine proteinases. The alignments of these SUCEST clusters with the sequence of cysteine proteinases of known origins provided important information about the classification and possible function of these sugarcane enzymes. Inferences about the expression pattern of each gene were made by direct correlation with the SUCEST cDNA libraries from which each cluster was derived. Since no previous reports of sugarcane cysteine proteinases genes exists, this study represents a first step in the study of new biochemical, physiological and biotechnological aspects of sugarcane cysteine proteases.Proteinases cisteínicas são peptidil-hidrolases dependentes de um resíduo de cisteína em seu sítio ativo. As propriedades físico-químicas destas proteinases têm sido amplamente caracterizadas, entretanto suas funções biológicas ainda não foram completamente elucidadas. Elas estão envolvidas em um grande número de eventos, tais como: processamento e degradação protéica, câncer, germinação, morte celular programada e processos de senescência. Diferentes proteinases cisteínicas, classificadas pelo Comitê de Nomenclatura da União Internacional de Bioquímica e Biologia Molecular (IUBMB como pertencentes à sub

  4. Identification of an evolutionarily conserved extracellular threonine residue critical for surface expression and its potential coupling of adjacent voltage-sensing and gating domains in voltage-gated potassium channels.

    Science.gov (United States)

    Mckeown, Lynn; Burnham, Matthew P; Hodson, Charlotte; Jones, Owen T

    2008-10-31

    The dynamic expression of voltage-gated potassium channels (Kvs) at the cell surface is a fundamental factor controlling membrane excitability. In exploring possible mechanisms controlling Kv surface expression, we identified a region in the extracellular linker between the first and second of the six (S1-S6) transmembrane-spanning domains of the Kv1.4 channel, which we hypothesized to be critical for its biogenesis. Using immunofluorescence microscopy, flow cytometry, patch clamp electrophysiology, and mutagenesis, we identified a single threonine residue at position 330 within the Kv1.4 S1-S2 linker that is absolutely required for cell surface expression. Mutation of Thr-330 to an alanine, aspartate, or lysine prevented surface expression. However, surface expression occurred upon co-expression of mutant and wild type Kv1.4 subunits or mutation of Thr-330 to a serine. Mutation of the corresponding residue (Thr-211) in Kv3.1 to alanine also caused intracellular retention, suggesting that the conserved threonine plays a generalized role in surface expression. In support of this idea, sequence comparisons showed conservation of the critical threonine in all Kv families and in organisms across the evolutionary spectrum. Based upon the Kv1.2 crystal structure, further mutagenesis, and the partial restoration of surface expression in an electrostatic T330K bridging mutant, we suggest that Thr-330 hydrogen bonds to equally conserved outer pore residues, which may include a glutamate at position 502 that is also critical for surface expression. We propose that Thr-330 serves to interlock the voltage-sensing and gating domains of adjacent monomers, thereby yielding a structure competent for the surface expression of functional tetramers.

  5. Ga2O3 photocatalyzed on-line tagging of cysteine to facilitate peptide mass fingerprinting.

    Science.gov (United States)

    Qiao, Liang; Su, Fangzheng; Bi, Hongyan; Girault, Hubert H; Liu, Baohong

    2011-09-01

    β-Ga(2)O(3) is a wide-band-gap semiconductor having strong oxidation ability under light irradiation. Herein, the steel target plates modified with β-Ga(2)O(3) nanoparticles have been developed to carry out in-source photo-catalytic oxidative reactions for online peptide tagging during laser desorption/ionization mass spectrometry (LDI-MS) analysis. Under UV laser irradiation, β-Ga(2)O(3) can catalyze the photo-oxidation of 2-methoxyhydroquinone added to a sample mixture to 2-methoxy benzoquinone that can further react with the thiol groups of cysteine residues by Michael addition reaction. The tagging process leads to appearance of pairs of peaks with an m/z shift of 138.1Th. This online labelling strategy is demonstrated to be sensitive and efficient with a detection-limit at femtomole level. Using the strategy, the information on cysteine content in peptides can be obtained together with peptide mass, therefore constraining the database searching for an advanced identification of cysteine-containing proteins from protein mixtures. The current peptide online tagging method can be important for specific analysis of cysteine-containing proteins especially the low-abundant ones that cannot be completely isolated from other high-abundant non-cysteine-proteins. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Can conservation agriculture improve phosphorus (P) availability in weathered soils? Effects of tillage and residue management on soil P status after 9 years in a Kenyan Oxisol

    NARCIS (Netherlands)

    Margenot, Andrew; Paul, B.K.; Pulleman, M.M.; Parikh, Sanjai; Fonte, Steven J.

    2017-01-01

    The widespread promotion of conservation agriculture (CA) in regions with weathered soils prone to phosphorus (P) deficiency merits explicit consideration of its effect on P availability. A long-term CA field trial located on an acid, weathered soil in western Kenya was evaluated for effects of

  7. Synthesis and Application of Aurophilic Poly(Cysteine and Poly(Cysteine-Containing Copolymers

    Directory of Open Access Journals (Sweden)

    David Ulkoski

    2017-10-01

    Full Text Available The redox capacity, as well as the aurophilicity of the terminal thiol side groups, in poly(Cysteine lend a unique characteristic to this poly(amino acid or polypeptide. There are two major application fields for this polymer: (i biomedical applications in drug delivery and surface modification of biomedical devices and (ii as coating for electrodes to enhance their electrochemical sensitivity. The intended application determines the synthetic route for p(Cysteine. Polymers to be used in biomedical applications are typically polymerized from the cysteine N-carboxyanhydride by a ring-opening polymerization, where the thiol group needs to be protected during the polymerization. Advances in this methodology have led to conditions under which the polymerization progresses as living polymerization, which allows for a strict control of the molecular architecture, molecular weight and polydispersity and the formation of block copolymers, which eventually could display polyphilic properties. Poly(Cysteine used as electrode coating is typically polymerized onto the electrode by cyclic voltammetry, which actually produces a continuous, pinhole-free film on the electrode via the formation of covalent bonds between the amino group of Cysteine and the carbon of the electrode. This resulting coating is chemically very different from the well-defined poly(Cysteine obtained by ring-opening polymerizations. Based on the structure of cysteine a significant degree of cross-linking within the coating deposited by cyclic voltammetry can be assumed. This manuscript provides a detailed discussion of the ring-opening polymerization of cysteine, a brief consideration of the role of glutathione, a key cysteine-containing tripeptide, and examples for the utilization of poly(Cysteine and poly(Cysteine-containing copolymers, in both, the biomedical as well as electrochemical realm.

  8. Cysteine reversal of the novel neuromuscular blocking drug CW002 in dogs: pharmacodynamics, acute cardiovascular effects, and preliminary toxicology.

    Science.gov (United States)

    Sunaga, Hiroshi; Malhotra, Jaideep K; Yoon, Edward; Savarese, John J; Heerdt, Paul M

    2010-04-01

    CW002 is a neuromuscular blocking drug that is inactivated by endogenous L-cysteine. This study determined the exogenous L-cysteine dose-response relationship for CW002 reversal along with acute cardiovascular effects and organ toxicity in dogs. Six dogs were each studied four times during isoflurane-nitrous oxide anesthesia and recording of muscle twitch, arterial pressure, and heart rate. CW002 (0.08 mg/kg or 9 x ED95) was injected, and the time to spontaneous muscle recovery was determined. CW002 was then administered again followed 1 min later by 10, 20, 50, or 100 mg/kg L-cysteine (1 dose/experiment). After twitch recovery, CW002 was given a third time to determine whether residual L-cysteine influenced duration. Preliminary toxicology was performed in an additional group of dogs that received CW002 followed by vehicle (n = 8) or 200 mg/kg L-cysteine (n = 8). Animals were awakened and observed for 2 or 14 days before sacrificing and anatomic, biochemical, and histopathologic analyses. L-cysteine at all doses accelerated recovery from CW002, with both 50 and 100 mg/kg decreasing median duration from more than 70 min to less than 5 min. After reversal, duration of a subsequent CW002 dose was also decreased in a dose-dependent manner. Over the studied dose range, L-cysteine had less than 10% effect on blood pressure and heart rate. Animals receiving a single 200-mg/kg dose of L-cysteine showed no clinical, anatomic, biochemical, or histologic evidence of organ toxicity. The optimal L-cysteine dose for rapidly reversing the neuromuscular blockade produced by a large dose of CW002 in dogs is approximately 50 mg/kg, which has no concomitant hemodynamic effect. A dose of 200 mg/kg had no evident organ toxicity.

  9. The Cysteine Protease–Cysteine Protease Inhibitor System Explored in Soybean Nodule Development

    Directory of Open Access Journals (Sweden)

    Marian Dorcas Quain

    2013-08-01

    Full Text Available Almost all protease families have been associated with plant development, particularly senescence, which is the final developmental stage of every organ before cell death. Proteolysis remobilizes and recycles nitrogen from senescent organs that is required, for example, seed development. Senescence-associated expression of proteases has recently been characterized using large-scale gene expression analysis seeking to identify and characterize senescence-related genes. Increasing activities of proteolytic enzymes, particularly cysteine proteases, are observed during the senescence of legume nodules, in which a symbiotic relationship between the host plant and bacteria (Rhizobia facilitate the fixation of atmospheric nitrogen. It is generally considered that cysteine proteases are compartmentalized to prevent uncontrolled proteolysis in nitrogen-fixing nodules. In addition, the activities of cysteine proteases are regulated by endogenous cysteine protease inhibitors called cystatins. These small proteins form reversible complexes with cysteine proteases, leading to inactivation. However, very little is currently known about how the cysteine protease-cysteine protease inhibitor (cystatin system is regulated during nodule development. Moreover, our current understanding of the expression and functions of proteases and protease inhibitors in nodules is fragmented. To address this issue, we have summarized the current knowledge and techniques used for studying proteases and their inhibitors including the application of “omics” tools, with a particular focus on changes in the cysteine protease-cystatin system during nodule development.

  10. Reduction of Guanosyl Radical by Cysteine and Cysteine-Glycine Studied by Time-Resolved CIDNP

    NARCIS (Netherlands)

    Morozova, O.B.; Kaptein, R.; Yurkovskaya, A.V.

    2012-01-01

    As a model for chemical DNA repair, reduction of guanosyl radicals in the reaction with cysteine or the dipeptide cysteine-glycine has been studied by time-resolved chemically induced dynamic nuclear polarization (CIDNP). Radicals were generated photochemically by pulsed laser irradiation of a

  11. Crystal Structure of Mammalian Cysteine dioxygenase: A Novel Mononuclear Iron Center for Cysteine Thiol Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons,C.; Liu, Q.; Huang, Q.; Hao, Q.; Begley, T.; Karplus, P.; Stipanuk, M.

    2006-01-01

    Cysteine dioxygenase is a mononuclear iron-dependent enzyme responsible for the oxidation of cysteine with molecular oxygen to form cysteinesulfinate. This reaction commits cysteine to either catabolism to sulfate and pyruvate or to the taurine biosynthetic pathway. Cysteine dioxygenase is a member of the cupin superfamily of proteins. The crystal structure of recombinant rat cysteine dioxygenase has been determined to 1.5 Angstroms resolution, and these results confirm the canonical cupin {beta}-sandwich fold and the rare cysteinyl-tyrosine intramolecular crosslink (between Cys93 and Tyr157) seen in the recently reported murine cysteine dioxygenase structure. In contrast to the catalytically inactive mononuclear Ni(II) metallocenter present in the murine structure, crystallization of a catalytically competent preparation of rat cysteine dioxygenase revealed a novel tetrahedrally coordinated mononuclear iron center involving three histidines (His86, His88, and His140) and a water molecule. Attempts to acquire a structure with bound ligand using either co-crystallization or soaks with cysteine revealed the formation of a mixed disulfide involving Cys164 near the active site, which may explain previously observed substrate inhibition. This work provides a framework for understanding the molecular mechanisms involved in thiol dioxygenation and sets the stage for exploring the chemistry of both the novel mononuclear iron center and the catalytic role of the cysteinyl-tyrosine linkage.

  12. Cysteine Biosynthesis Controls Serratia marcescens Phospholipase Activity.

    Science.gov (United States)

    Anderson, Mark T; Mitchell, Lindsay A; Mobley, Harry L T

    2017-08-15

    Serratia marcescens causes health care-associated opportunistic infections that can be difficult to treat due to a high incidence of antibiotic resistance. One of the many secreted proteins of S. marcescens is the PhlA phospholipase enzyme. Genes involved in the production and secretion of PhlA were identified by screening a transposon insertion library for phospholipase-deficient mutants on phosphatidylcholine-containing medium. Mutations were identified in four genes ( cyaA , crp , fliJ , and fliP ) that are involved in the flagellum-dependent PhlA secretion pathway. An additional phospholipase-deficient isolate harbored a transposon insertion in the cysE gene encoding a predicted serine O -acetyltransferase required for cysteine biosynthesis. The cysE requirement for extracellular phospholipase activity was confirmed using a fluorogenic phospholipase substrate. Phospholipase activity was restored to the cysE mutant by the addition of exogenous l-cysteine or O -acetylserine to the culture medium and by genetic complementation. Additionally, phlA transcript levels were decreased 6-fold in bacteria lacking cysE and were restored with added cysteine, indicating a role for cysteine-dependent transcriptional regulation of S. marcescens phospholipase activity. S. marcescens cysE mutants also exhibited a defect in swarming motility that was correlated with reduced levels of flhD and fliA flagellar regulator gene transcription. Together, these findings suggest a model in which cysteine is required for the regulation of both extracellular phospholipase activity and surface motility in S. marcescens IMPORTANCE Serratia marcescens is known to secrete multiple extracellular enzymes, but PhlA is unusual in that this protein is thought to be exported by the flagellar transport apparatus. In this study, we demonstrate that both extracellular phospholipase activity and flagellar function are dependent on the cysteine biosynthesis pathway. Furthermore, a disruption of cysteine

  13. Global alteration of the drug-binding pocket of human P-glycoprotein (ABCB1) by substitution of fifteen conserved residues reveals a negative correlation between substrate size and transport efficiency.

    Science.gov (United States)

    Vahedi, Shahrooz; Chufan, Eduardo E; Ambudkar, Suresh V

    2017-11-01

    P-glycoprotein (P-gp), an ATP-dependent efflux pump, is linked to the development of multidrug resistance in cancer cells. However, the drug-binding sites and translocation pathways of this transporter are not yet well-characterized. We recently demonstrated the important role of tyrosine residues in regulating P-gp ATP hydrolysis via hydrogen bond formations with high affinity modulators. Since tyrosine is both a hydrogen bond donor and acceptor, and non-covalent interactions are key in drug transport, in this study we investigated the global effect of enrichment of tyrosine residues in the drug-binding pocket on the drug binding and transport function of P-gp. By employing computational analysis, 15 conserved residues in the drug-binding pocket of human P-gp that interact with substrates were identified and then substituted with tyrosine, including 11 phenylalanine (F72, F303, F314, F336, F732, F759, F770, F938, F942, F983, F994), two leucine (L339, L975), one isoleucine (I306), and one methionine (M949). Characterization of the tyrosine-rich P-gp mutant in HeLa cells demonstrated that this major alteration in the drug-binding pocket by introducing fifteen additional tyrosine residues is well tolerated and has no measurable effect on total or cell surface expression of this mutant. Although the tyrosine-enriched mutant P-gp could transport small to moderate size (transport large (>1000 Daltons) substrates such as NBD-cyclosporine A, Bodipy-paclitaxel and Bodipy-vinblastine was significantly decreased. This was further supported by the physico-chemical characterization of seventeen tested substrates, which revealed a negative correlation between drug transport and molecular size for the tyrosine-enriched P-gp mutant. Published by Elsevier Inc.

  14. Cysteine-independent activation/inhibition of heme oxygenase-2

    Directory of Open Access Journals (Sweden)

    Dragic Vukomanovic

    2016-01-01

    Full Text Available Reactive thiols of cysteine (cys residues in proteins play a key role in transforming chemical reactivity into a biological response. The heme oxygenase-2 (HO-2 isozyme contains two cys residues that have been implicated in binding of heme and also the regulation of its activity. In this paper, we address the question of a role for cys residues for the HO-2 inhibitors or activators designed in our laboratory. We tested the activity of full length recombinant human heme oxygenase-2 (FL-hHO-2 and its analog in which cys265 and cys282 were both replaced by alanine to determine the effect on activation by menadione (MD and inhibition by QC-2350. Similar inhibition by QC-2350 and almost identical activation by MD was observed for both recombinant FL-hHO-2s. Our findings are interpreted to mean that thiols of FL-hHO-2s are not involved in HO-2 activation or inhibition by the compounds that have been designed and identified by us. Activation or inhibition of HO-2 by our compounds should be attributed to a mechanism other than altering binding affinity of HO-2 for heme through cys265 and cys282.

  15. Mutation choice to eliminate buried free cysteines in protein therapeutics.

    Science.gov (United States)

    Xia, Xue; Longo, Liam M; Blaber, Michael

    2015-02-01

    Buried free-cysteine (Cys) residues can contribute to an irreversible unfolding pathway that promotes protein aggregation, increases immunogenic potential, and significantly reduces protein functional half-life. Consequently, mutation of buried free-Cys residues can result in significant improvement in the storage, reconstitution, and pharmacokinetic properties of protein-based therapeutics. Mutational design to eliminate buried free-Cys residues typically follows one of two common heuristics: either substitution by Ser (polar and isosteric), or substitution by Ala or Val (hydrophobic); however, a detailed structural and thermodynamic understanding of Cys mutations is lacking. We report a comprehensive structure and stability study of Ala, Ser, Thr, and Val mutations at each of the three buried free-Cys positions (Cys16, Cys83, and Cys117) in fibroblast growth factor-1. Mutation was almost universally destabilizing, indicating a general optimization for the wild-type Cys, including van der Waals and H-bond interactions. Structural response to Cys mutation characteristically involved changes to maintain, or effectively substitute, local H-bond interactions-by either structural collapse to accommodate the smaller oxygen radius of Ser/Thr, or conversely, expansion to enable inclusion of novel H-bonding solvent. Despite the diverse structural effects, the least destabilizing average substitution at each position was Ala, and not isosteric Ser. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  16. Cysteine-independent activation/inhibition of heme oxygenase-2.

    Science.gov (United States)

    Vukomanovic, Dragic; Rahman, Mona N; Maines, Mahin D; Ozolinš, Terence Rs; Szarek, Walter A; Jia, Zongchao; Nakatsu, Kanji

    2016-03-01

    Reactive thiols of cysteine (cys) residues in proteins play a key role in transforming chemical reactivity into a biological response. The heme oxygenase-2 (HO-2) isozyme contains two cys residues that have been implicated in binding of heme and also the regulation of its activity. In this paper, we address the question of a role for cys residues for the HO-2 inhibitors or activators designed in our laboratory. We tested the activity of full length recombinant human heme oxygenase-2 (FL-hHO-2) and its analog in which cys265 and cys282 were both replaced by alanine to determine the effect on activation by menadione (MD) and inhibition by QC-2350. Similar inhibition by QC-2350 and almost identical activation by MD was observed for both recombinant FL-hHO-2s. Our findings are interpreted to mean that thiols of FL-hHO-2s are not involved in HO-2 activation or inhibition by the compounds that have been designed and identified by us. Activation or inhibition of HO-2 by our compounds should be attributed to a mechanism other than altering binding affinity of HO-2 for heme through cys265 and cys282.

  17. Alternatives to crop residues for soil amendment

    OpenAIRE

    Powell, J.M.; Unger, P.W.

    1997-01-01

    Metadata only record In semiarid agroecosystems, crop residues can provide important benefits of soil and water conservation, nutrient cycling, and improved subsequent crop yields. However, there are frequently multiple competing uses for residues, including animal forage, fuel, and construction material. This chapter discusses the various uses of crop residues and examines alternative soil amendments when crop residues cannot be left on the soil.

  18. Mechanism of Sirt1 NAD+-dependent Protein Deacetylase Inhibition by Cysteine S-Nitrosation.

    Science.gov (United States)

    Kalous, Kelsey S; Wynia-Smith, Sarah L; Olp, Michael D; Smith, Brian C

    2016-12-02

    The sirtuin family of proteins catalyze the NAD + -dependent deacylation of acyl-lysine residues. Humans encode seven sirtuins (Sirt1-7), and recent studies have suggested that post-translational modification of Sirt1 by cysteine S-nitrosation correlates with increased acetylation of Sirt1 deacetylase substrates. However, the mechanism of Sirt1 inhibition by S-nitrosation was unknown. Here, we show that Sirt1 is transnitrosated and inhibited by the physiologically relevant nitrosothiol S-nitrosoglutathione. Steady-state kinetic analyses and binding assays were consistent with Sirt1 S-nitrosation inhibiting binding of both the NAD + and acetyl-lysine substrates. Sirt1 S-nitrosation correlated with Zn 2+ release from the conserved sirtuin Zn 2+ -tetrathiolate and a loss of α-helical structure without overall thermal destabilization of the enzyme. Molecular dynamics simulations suggested that Zn 2+ loss due to Sirt1 S-nitrosation results in repositioning of the tetrathiolate subdomain away from the rest of the catalytic domain, thereby disrupting the NAD + and acetyl-lysine-binding sites. Sirt1 S-nitrosation was reversed upon exposure to the thiol-based reducing agents, including physiologically relevant concentrations of the cellular reducing agent glutathione. Reversal of S-nitrosation resulted in full restoration of Sirt1 activity only in the presence of Zn 2+ , consistent with S-nitrosation of the Zn 2+ -tetrathiolate as the primary source of Sirt1 inhibition upon S-nitrosoglutathione treatment. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Cysteine proteases as potential antigens in antiparasitic DNA vaccines

    DEFF Research Database (Denmark)

    Jørgensen, Louise von Gersdorff; Buchmann, Kurt

    2011-01-01

    En litteraturgennemgang af muligheder for at bruge cystein proteaser som antigener i antiparasitære vacciner.......En litteraturgennemgang af muligheder for at bruge cystein proteaser som antigener i antiparasitære vacciner....

  20. 21 CFR 184.1271 - L-Cysteine.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true L-Cysteine. 184.1271 Section 184.1271 Food and... Substances Affirmed as GRAS § 184.1271 L-Cysteine. (a) L-Cysteine is the chemical L-2-amino-3... of total L-cysteine per 100 parts of flour in dough as a dough strengthener as defined in § 170.3(o...

  1. 21 CFR 184.1272 - L-Cysteine monohydrochloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true L-Cysteine monohydrochloride. 184.1272 Section 184... Listing of Specific Substances Affirmed as GRAS § 184.1272 L-Cysteine monohydrochloride. (a) L-Cysteine... ingredient is used to supply up to 0.009 part of total L-cysteine per 100 parts of flour in dough as a dough...

  2. Impact of cysteine variants on the structure, activity, and stability of recombinant human α-galactosidase A

    Science.gov (United States)

    Qiu, Huawei; Honey, Denise M; Kingsbury, Jonathan S; Park, Anna; Boudanova, Ekaterina; Wei, Ronnie R; Pan, Clark Q; Edmunds, Tim

    2015-01-01

    Recombinant human α-galactosidase A (rhαGal) is a homodimeric glycoprotein deficient in Fabry disease, a lysosomal storage disorder. In this study, each cysteine residue in rhαGal was replaced with serine to understand the role each cysteine plays in the enzyme structure, function, and stability. Conditioned media from transfected HEK293 cells were assayed for rhαGal expression and enzymatic activity. Activity was only detected in the wild type control and in mutants substituting the free cysteine residues (C90S, C174S, and the C90S/C174S). Cysteine-to-serine substitutions at the other sites lead to the loss of expression and/or activity, consistent with their involvement in the disulfide bonds found in the crystal structure. Purification and further characterization confirmed that the C90S, C174S, and the C90S/C174S mutants are enzymatically active, structurally intact and thermodynamically stable as measured by circular dichroism and thermal denaturation. The purified inactive C142S mutant appeared to have lost part of its alpha-helix secondary structure and had a lower apparent melting temperature. Saturation mutagenesis study on Cys90 and Cys174 resulted in partial loss of activity for Cys174 mutants but multiple mutants at Cys90 with up to 87% higher enzymatic activity (C90T) compared to wild type, suggesting that the two free cysteines play differential roles and that the activity of the enzyme can be modulated by side chain interactions of the free Cys residues. These results enhanced our understanding of rhαGal structure and function, particularly the critical roles that cysteines play in structure, stability, and enzymatic activity. PMID:26044846

  3. Mutations at the cysteine codons of the recA gene of Escherichia coli

    International Nuclear Information System (INIS)

    Weisemann, J.M.; Weinstock, G.M.

    1988-01-01

    Each of the three cysteine residues in the Escherichia coli RecA protein was replaced with a number of other amino acids. To do this, each cysteine codon was first converted to a chain-terminating amber codon by oligonucleotide-directed mutagenesis. These amber mutants were then either assayed for function in different suppressor strains or reverted by a second round of mutagenesis with oligonucleotides that had random sequences at the amber codon. Thirty-three different amino acid substitutions were obtained. Mutants were tested for three functions of RecA: survival following UV irradiation, homologous recombination, and induction of the SOS response. It was found that although none of the cysteines is essential for activity, mutations at each of these positions can affect one or more of the activities of RecA, depending on the particular amino acid substitution. In addition, the cysteine at position 116 appears to be involved in the RecA-promoted cleavage of the LexA protein

  4. Effect of free cysteine on the denaturation and aggregation of holo α-lactalbumin

    DEFF Research Database (Denmark)

    Nielsen, Line R.; Lund, Marianne N.; Davies, Michael J.

    2018-01-01

    α-Lactalbumin (α-LA) is a key commercial whey protein for nutritional purposes. The holo protein (calcium saturated) is considered the most heat stable whey protein, capable of refolding from unfolded states under many conditions. This is due to the absence of free thiols (cysteine residues......) that are typically involved in thermal aggregation and thiol–disulphide exchange reactions of other whey proteins. Heating (0–120 min at 90 °C, pH 7.0) holo α-LA generates free thiols through thermal cleavage of disulphide bonds, resulting in aggregates comprising unfolded α-LA species. The addition of free cysteine...... promotes the formation of soluble aggregates, effectively decreasing the holding time required to reach a particular aggregate size in a dose-dependent manner (0.35–1.4 mM cysteine). Excess cysteine (≥14 mM) causes a destabilisation of α-LA, shown by decreased denaturation temperature and gel formation...

  5. Recurrence and mortality according to Estrogen Receptor status for breast cancer patients undergoing conservative surgery. Ipsilateral breast tumour recurrence dynamics provides clues for tumour biology within the residual breast

    International Nuclear Information System (INIS)

    Demicheli, Romano; Ardoino, Ilaria; Boracchi, Patrizia; Coradini, Danila; Agresti, Roberto; Ferraris, Cristina; Gennaro, Massimiliano; Hrushesky, William JM; Biganzoli, Elia

    2010-01-01

    the study was designed to determine how tumour hormone receptor status affects the subsequent pattern over time (dynamics) of breast cancer recurrence and death following conservative primary breast cancer resection. Time span from primary resection until both first recurrence and death were considered among 2825 patients undergoing conservative surgery with or without breast radiotherapy. The hazard rates for ipsilateral breast tumour recurrence (IBTR), distant metastasis (DM) and mortality throughout 10 years of follow-up were assessed. DM dynamics displays the same bimodal pattern (first early peak at about 24 months, second late peak at the sixth-seventh year) for both estrogen receptor (ER) positive (P) and negative (N) tumours and for all local treatments and metastatic sites. The hazard rates for IBTR maintain the bimodal pattern for ERP and ERN tumours; however, each IBTR recurrence peak for ERP tumours is delayed in comparison to the corresponding timing of recurrence peaks for ERN tumours. Mortality dynamics is markedly different for ERP and ERN tumours with more early deaths among patients with ERN than among patients with ERP primary tumours. DM dynamics is not influenced by the extent of conservative primary tumour resection and is similar for both ER phenotypes across different metastatic sites, suggesting similar mechanisms for tumour development at distant sites despite apparently different microenvironments. The IBTR risk peak delay observed in ERP tumours is an exception to the common recurrence risk rhythm. This suggests that the microenvironment within the residual breast tissue may enforce more stringent constraints upon ERP breast tumour cell growth than other tissues, prolonging the latency of IBTR. This local environment is, however, apparently less constraining to ERN cells, as IBTR dynamics is similar to the corresponding recurrence dynamics among other distant tissues

  6. Harvey murine sarcoma virus p21 ras protein: biological and biochemical significance of the cysteine nearest the carboxy terminus

    DEFF Research Database (Denmark)

    Willumsen, B M; Norris, K; Papageorge, A G

    1984-01-01

    localization. We have now further characterized the post-translational processing of these mutants and have also studied two C-terminal v-rasH point mutants: one encodes serine in place of cysteine-186, the other threonine for valine-187. The Thr-187 mutant was transformation-competent, and its p21 protein...... not undergo the posttranslational processing common to biologically active ras proteins: their electrophoretic migration rate did not change, they remained in the cytosol, and they failed to bind lipid. Since the cell-encoded ras proteins also contain this cysteine, we conclude that this amino acid residue...

  7. Tumor residual pós-quimioterapia neoadjuvante para câncer de mama: impacto sobre o tratamento cirúrgico conservador Residual tumor after neoadjuvant chemotherapy for breast cancer: impact on conservative surgical treatment

    Directory of Open Access Journals (Sweden)

    Edison Mantovani Barbosa

    1999-05-01

    regression occurred irregularly, several refractory tumor cells remaining at the primary tumor site. Resistant tumor cells, independent of the primary tumor, were found in mammary tissue. Other histopathological findings, resulting from chemotherapy in tumoral and mammary tissues, such as calcifications and fibrosis, and in axillary homolateral lymph nodes were obtained. Conclusion: the effect of neoadjuvant chemotherapy is not uniform, refratory tumor cells remaining not only at primary tumor site, but also in distant regions. Furthermore, we found no correlation between the regression of the tumor and the axillary metastatic lymph nodes. Thus, a conservative surgery after neoadjuvant chemotherapy (FEC should be avoided.

  8. L-Cysteine Metabolism and Fermentation in Microorganisms.

    Science.gov (United States)

    Takagi, Hiroshi; Ohtsu, Iwao

    L-Cysteine is an important amino acid both biologically and commercially. Although most amino acids are industrially produced by microbial fermentation, L-cysteine has been mainly produced by protein hydrolysis. Due to environmental and safety problems, synthetic or biotechnological products have been preferred in the market. Here, we reviewed L-cysteine metabolism, including biosynthesis, degradation, and transport, and biotechnological production (including both enzymatic and fermentation processes) of L-cysteine. The metabolic regulation of L-cysteine including novel sulfur metabolic pathways found in microorganisms is also discussed. Recent advancement in biochemical studies, genome sequencing, structural biology, and metabolome analysis has enabled us to use various approaches to achieve direct fermentation of L-cysteine from glucose. For example, worldwide companies began to supply L-cysteine and its derivatives produced by bacterial fermentation. These companies successfully optimized the original metabolism of their private strains. Basically, a combination of three factors should be required for improving L-cysteine fermentation: that is, (1) enhancing biosynthesis: overexpression of the altered cysE gene encoding feedback inhibition-insensitive L-serine O-acetyltransferase (SAT), (2) weakening degradation: knockout of the genes encoding L-cysteine desulfhydrases, and (3) exploiting export system: overexpression of the gene involved in L-cysteine transport. Moreover, we found that "thiosulfate" is much more effective sulfur source than commonly used "sulfate" for L-cysteine production in Escherichia coli, because thiosulfate is advantageous for saving consumption of NADPH and relating energy molecules.

  9. Dual Labeling Biotin Switch Assay to Reduce Bias Derived From Different Cysteine Subpopulations: A Method to Maximize S-Nitrosylation Detection.

    Science.gov (United States)

    Chung, Heaseung Sophia; Murray, Christopher I; Venkatraman, Vidya; Crowgey, Erin L; Rainer, Peter P; Cole, Robert N; Bomgarden, Ryan D; Rogers, John C; Balkan, Wayne; Hare, Joshua M; Kass, David A; Van Eyk, Jennifer E

    2015-10-23

    S-nitrosylation (SNO), an oxidative post-translational modification of cysteine residues, responds to changes in the cardiac redox-environment. Classic biotin-switch assay and its derivatives are the most common methods used for detecting SNO. In this approach, the labile SNO group is selectively replaced with a single stable tag. To date, a variety of thiol-reactive tags have been introduced. However, these methods have not produced a consistent data set, which suggests an incomplete capture by a single tag and potentially the presence of different cysteine subpopulations. To investigate potential labeling bias in the existing methods with a single tag to detect SNO, explore if there are distinct cysteine subpopulations, and then, develop a strategy to maximize the coverage of SNO proteome. We obtained SNO-modified cysteine data sets for wild-type and S-nitrosoglutathione reductase knockout mouse hearts (S-nitrosoglutathione reductase is a negative regulator of S-nitrosoglutathione production) and nitric oxide-induced human embryonic kidney cell using 2 labeling reagents: the cysteine-reactive pyridyldithiol and iodoacetyl based tandem mass tags. Comparison revealed that <30% of the SNO-modified residues were detected by both tags, whereas the remaining SNO sites were only labeled by 1 reagent. Characterization of the 2 distinct subpopulations of SNO residues indicated that pyridyldithiol reagent preferentially labels cysteine residues that are more basic and hydrophobic. On the basis of this observation, we proposed a parallel dual-labeling strategy followed by an optimized proteomics workflow. This enabled the profiling of 493 SNO sites in S-nitrosoglutathione reductase knockout hearts. Using a protocol comprising 2 tags for dual-labeling maximizes overall detection of SNO by reducing the previously unrecognized labeling bias derived from different cysteine subpopulations. © 2015 American Heart Association, Inc.

  10. Quercetin targets cysteine string protein (CSPalpha and impairs synaptic transmission.

    Directory of Open Access Journals (Sweden)

    Fenglian Xu

    2010-06-01

    Full Text Available Cysteine string protein (CSPalpha is a synaptic vesicle protein that displays unique anti-neurodegenerative properties. CSPalpha is a member of the conserved J protein family, also called the Hsp40 (heat shock protein of 40 kDa protein family, whose importance in protein folding has been recognized for many years. Deletion of the CSPalpha in mice results in knockout mice that are normal for the first 2-3 weeks of life followed by an unexplained presynaptic neurodegeneration and premature death. How CSPalpha prevents neurodegeneration is currently not known. As a neuroprotective synaptic vesicle protein, CSPalpha represents a promising therapeutic target for the prevention of neurodegenerative disorders.Here, we demonstrate that the flavonoid quercetin promotes formation of stable CSPalpha-CSPalpha dimers and that quercetin-induced dimerization is dependent on the unique cysteine string region. Furthermore, in primary cultures of Lymnaea neurons, quercetin induction of CSPalpha dimers correlates with an inhibition of synapse formation and synaptic transmission suggesting that quercetin interfers with CSPalpha function. Quercetin's action on CSPalpha is concentration dependent and does not promote dimerization of other synaptic proteins or other J protein family members and reduces the assembly of CSPalpha:Hsc70 units (70kDa heat shock cognate protein.Quercetin is a plant derived flavonoid and popular nutritional supplement proposed to prevent memory loss and altitude sickness among other ailments, although its precise mechanism(s of action has been unclear. In view of the therapeutic promise of upregulation of CSPalpha and the undesired consequences of CSPalpha dysfunction, our data establish an essential proof of principle that pharmaceutical agents can selectively target the neuroprotective J protein CSPalpha.

  11. Determination of Disulfide Bond Connectivity of Cysteine-rich Peptide IpTx{sub a}

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chul Won; Kim, Jim Il [Chonnam National Univ., Gwangju (Korea, Republic of); Sato, Kazuki [Fukuoka Women' s Univ., Fukuoka (Japan)

    2013-06-15

    Cysteine-rich peptides stabilized by intramolecular disulfide bonds have often been isolated from venoms of microbes, animals and plants. These peptides typically have much higher stability and improved biopharmaceutical properties compared to their linear counterparts. Therefore the correct disulfide bond formation of small proteins and peptides has been extensively studied for a better understanding of their folding mechanism and achieving efficient generation of the naturally occurring biologically active product. Imperatoxin A (IpTx{sub a}), a peptide toxin containing 6 cysteine residues, was isolated from the venom of scorpion Pandinus imperator, selectively binds the ryanodine receptors and activates Ca{sup 2+} release from sarcoplasmic reticulum (SR). IpTx{sub a} increases the binding of ryanodine to ryanodine receptors (RyRs) and encourages reconstituted single channel to induce subconductance states.

  12. Solution structure of the twelfth cysteine-rich ligand-binding repeat in rat megalin

    International Nuclear Information System (INIS)

    Wolf, Christian A.; Dancea, Felician; Shi Meichen; Bade-Noskova, Veronika; Rueterjans, Heinz; Kerjaschki, Dontscho; Luecke, Christian

    2007-01-01

    Megalin, an approx. 600 kDa transmembrane glycoprotein that acts as multi-ligand transporter, is a member of the low density lipoprotein receptor gene family. Several cysteine-rich repeats, each consisting of about 40 residues, are responsible for the multispecific binding of ligands. The solution structure of the twelfth cysteine-rich ligand-binding repeat with class A motif found in megalin features two short β-strands and two helical turns, yielding the typical fold with a I-III, II-V and IV-VI disulfide bridge connectivity pattern and a calcium coordination site at the C-terminal end. The resulting differences in electrostatic surface potential compared to other ligand-binding modules of this gene family, however, may be responsible for the functional divergence

  13. The mitochondrial toxicity of cysteine-S-conjugates: Studies with pentachlorobutadienyl-L-cysteine

    International Nuclear Information System (INIS)

    Wallin, A.

    1990-01-01

    Nephrotoxic cysteine conjugates, arising from mercapturate biosynthesis, can perturb the mitochondrial membrane potential and calcium homeostasis in renal epithelial cells. Activation of these cysteine conjugates to reactive species by mitochondrial β-lyases results in covalent binding and mitochondrial damage. PCBC and related cysteine conjugates inhibit ADP-stimulated respiration in mitochondria respiring on alpha-ketoglutrate/malate and succinate indicating that both dehydrogenases may be targets. The respiratory inhibition is blocked by aminooxyacetic acid, an inhibitor of the β-lyase. Hence, metabolic activation is required implying that covalent binding of reactive intermediates may be important to the mitochondrial injury. Binding of 35 S-fragments has been found for 5 conjugates with varying degrees of mitochondrial toxicity. PCBC is more lipophilic and has a higher affinity for cellular membranes than other cysteine conjugates. PCBC rapidly depolarizes the inner membrane potential resulting in an inhibition of mitochondrial oxidative phosphorylation and calcium upon sequestration. Consequently, mitochondria and renal epithelial cells exposed to PCBC show a sudden release of calcium upon exposure to PCBC which is followed by a later increase in state 4 respiration leading to an inhibition of oxidative phosphorylation. The primary effect of other cysteine conjugates is an inhibition of the dehydrogenases, thus inhibiting state 3 respiration

  14. Enzyme II/sup Mtl/ of the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system: identification of the activity-linked cysteine on the mannitol carrier

    International Nuclear Information System (INIS)

    Pas, H.H.; Robillard, G.T.

    1988-01-01

    The cysteine of the membrane-bound mannitol-specific enzyme II (EII/sup Mtl/) of the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system have been labeled with 4-vinylpyridine. After proteolytic breakdown and reversed-phase HPLC, the peptides containing cysteines 110, 384, and 571 could be identified. N-Ethylmaleimide (NEM) treatment of the native unphosphorylated enzyme results in incorporation of one NEM label per molecule and loss of enzymatic activity. NEM treatment and inactivation prevented 4-vinylpyridine incorporation into the Cys-384-containing peptide, identifying this residue as the activity-linked cysteine. Both oxidation and phosphorylation of the native enzyme protected the enzyme against NEM labeling of Cys-384. Positive identification of the activity-linked cysteine was accomplished by inactivation with [ 14 C]iodoacetamide, proteolytic fragmentation, isolation of the peptide, and amino acid sequencing

  15. Rethinking Cysteine Protective Groups: S-Alkylsulfonyl-l-Cysteines for Chemoselective Disulfide Formation.

    Science.gov (United States)

    Schäfer, Olga; Huesmann, David; Muhl, Christian; Barz, Matthias

    2016-12-12

    The ability to reversibly cross-link proteins and peptides grants the amino acid cysteine its unique role in nature as well as in peptide chemistry. We report a novel class of S-alkylsulfonyl-l-cysteines and N-carboxy anhydrides (NCA) thereof for peptide synthesis. The S-alkylsulfonyl group is stable against amines and thus enables its use under Fmoc chemistry conditions and the controlled polymerization of the corresponding NCAs yielding well-defined homo- as well as block co-polymers. Yet, thiols react immediately with the S-alkylsulfonyl group forming asymmetric disulfides. Therefore, we introduce the first reactive cysteine derivative for efficient and chemoselective disulfide formation in synthetic polypeptides, thus bypassing additional protective group cleavage steps. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Contributions of a disulfide bond and a reduced cysteine side chain to the intrinsic activity of the high-density lipoprotein receptor SR-BI.

    Science.gov (United States)

    Yu, Miao; Lau, Thomas Y; Carr, Steven A; Krieger, Monty

    2012-12-18

    The high-density lipoprotein (HDL) receptor scavenger receptor class B, type I (SR-BI), binds HDL and mediates selective cholesteryl ester uptake. SR-BI's structure and mechanism are poorly understood. We used mass spectrometry to assign the two disulfide bonds in SR-BI that connect cysteines within the conserved Cys(321)-Pro(322)-Cys(323) (CPC) motif and connect Cys(280) to Cys(334). We used site-specific mutagenesis to evaluate the contributions of the CPC motif and the side chain of extracellular Cys(384) to HDL binding and lipid uptake. The effects of CPC mutations on activity were context-dependent. Full wild-type (WT) activity required Pro(322) and Cys(323) only when Cys(321) was present. Reduced intrinsic activities were observed for CXC and CPX, but not XXC, XPX, or XXX mutants (X ≠ WT residue). Apparently, a free thiol side chain at position 321 that cannot form an intra-CPC disulfide bond with Cys(323) is deleterious, perhaps because of aberrant disulfide bond formation. Pro(322) may stabilize an otherwise strained CPC disulfide bond, thus supporting WT activity, but this disulfide bond is not absolutely required for normal activity. C(384)X (X = S, T, L, Y, G, or A) mutants exhibited altered activities that varied with the side chain's size: larger side chains phenocopied WT SR-BI treated with its thiosemicarbazone inhibitor BLT-1 (enhanced binding, weakened uptake); smaller side chains produced almost inverse effects (increased uptake:binding ratio). C(384)X mutants were BLT-1-resistant, supporting the proposal that Cys(384)'s thiol interacts with BLT-1. We discuss the implications of our findings on the functions of the extracellular loop cysteines in SR-BI and compare our results to those presented by other laboratories.

  17. Conserved water-mediated H-bonding dynamics of catalytic Asn ...

    Indian Academy of Sciences (India)

    Prakash

    Extensive energy minimization and molecular dynamics simulation studies up to 2 ns ... Conserved water in molecular recognition; MD simulation; plant cysteine protease ..... Mustata G and Briggs J M 2004 Cluster analysis of water molecules.

  18. Cycling of grain legume residue nitrogen

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1995-01-01

    Symbiotic nitrogen fixation by legumes is the main input of nitrogen in ecological agriculture. The cycling of N-15-labelled mature pea (Pisum sativum L.) residues was studied during three years in small field plots and lysimeters. The residual organic labelled N declined rapidly during the initial...... management methods in order to conserve grain legume residue N sources within the soil-plant system....

  19. Pulse photolysis of NADH in the presence of cysteine

    International Nuclear Information System (INIS)

    Scheel, H.E.

    1976-01-01

    In the UV irradiation of NADH under anaerobic conditions, cysteine, which often acts as a radioprotective substance, has a sensitizing effect. With the aid of pulse photolysis, it was studied which reaction mechanisms in the presence or absence of cysteine are responsible for the damage to NADH in aqueous solution. In the absence of cysteine, the characteristic NADH absorption at 340 nm is reduced immediately after UV quanta have been absorbed by the adenine fraction of the molecules; in the presence of cysteine, a secondary reaction causes additional damage. The spectra of the intermediate products of NADH and cysteine have been recorded for different cysteine concentrations, and the reaction constants have been determined. These values suggest that the sensitizing effect is due to a reaction of NADH with radical anions produced by photolysis. (orig.) [de

  20. Modulation of ion transport across rat distal colon by cysteine

    Directory of Open Access Journals (Sweden)

    Martin eDiener

    2012-03-01

    Full Text Available The aim of this study was to identify the actions of stimulation of endogenous production of H2S by cysteine, the substrate for the two H2S-producing enzymes, cystathionin-beta-synthase and cystathionin-gamma-lyase, on ion transport across rat distal colon. Changes in short-circuit current (Isc induced by cysteine were measured in Ussing chambers. Free cysteine caused a concentration-dependent, transient fall in Isc, which was sensitive to amino-oxyacetate and beta-cyano-L-alanine, i.e. inhibitors of H2S-producing enzymes. In contrast, Na cysteinate evoked a biphasic change in Isc, i.e. an initial fall followed by a secondary increase, which was also reduced by these enzyme inhibitors. All responses were dependent on the presence of Cl- and inhibited by bumetanide, suggesting that free cysteine induces an inhibition of transcellular Cl- secretion, whereas Na cysteinate – after a transient inhibitory phase – activates anion secretion. The assumed reason for this discrepancy is a fall in the cytosolic pH induced by free cysteine, but not by Na cysteinate, as observed in isolated colonic crypts loaded with the pH-sensitive dye, BCECF. Intracellular acidification is known to inhibit epithelial K+ channels. Indeed, after preinhibition of basolateral K+ channels with tetrapentylammonium or Ba2+, the negative Isc induced by free cysteine was reduced significantly. In consequence, stimulation of endogenous H2S production by Na cysteinate causes, after a short inhibitory response, a delayed activation of anion secretion, which is missing in the case of free cysteine, probably due to the cytosolic acidification. In contrast, diallyl trisulfide, which is intracellularly converted to H2S, only evoked a monophasic increase in Isc without the initial fall observed with Na cysteinate. Consequently, time course and amount of produced H2S seem to strongly influence the functional response of the colonic epithelium evoked by this gasotransmitter.

  1. Cysteine-containing peptides having antioxidant properties

    Science.gov (United States)

    Bielicki, John K [Castro Valley, CA

    2008-10-21

    Cysteine containing amphipathic alpha helices of the exchangeable apolipoproteins, as exemplified by apolipoprotein (apo) A-I.sub.Milano (R173C) and apoA-I.sub.Paris, (R151C) were found to exhibit potent antioxidant activity on phospholipid surfaces. The addition of a free thiol, at the hydrophobic/hydrophilic interface of an amphipathic alpha helix of synthetic peptides that mimic HDL-related proteins, imparts a unique antioxidant activity to these peptides which inhibits lipid peroxidation and protects phospholipids from water-soluble free radical initiators. These peptides can be used as therapeutic agents to combat cardiovascular disease, ischemia, bone disease and other inflammatory related diseases.

  2. The interaction between thermodynamic stability and buried free cysteines in regulating the functional half-life of fibroblast growth factor-1.

    Science.gov (United States)

    Lee, Jihun; Blaber, Michael

    2009-10-16

    Protein biopharmaceuticals are an important and growing area of human therapeutics; however, the intrinsic property of proteins to adopt alternative conformations (such as during protein unfolding and aggregation) presents numerous challenges, limiting their effective application as biopharmaceuticals. Using fibroblast growth factor-1 as model system, we describe a cooperative interaction between the intrinsic property of thermostability and the reactivity of buried free-cysteine residues that can substantially modulate protein functional half-life. A mutational strategy that combines elimination of buried free cysteines and secondary mutations that enhance thermostability to achieve a substantial gain in functional half-life is described. Furthermore, the implementation of this design strategy utilizing stabilizing mutations within the core region resulted in a mutant protein that is essentially indistinguishable from wild type as regard protein surface and solvent structure, thus minimizing the immunogenic potential of the mutations. This design strategy should be generally applicable to soluble globular proteins containing buried free-cysteine residues.

  3. Heterologous expression of Hordeum vulgare cysteine protease in yeast

    DEFF Research Database (Denmark)

    Rosenkilde, Anne Lind; Dionisio, Giuseppe; Holm, Preben B

    Cysteine Proteases accounts for more than 90 % of the total proteolytic activity in the degradation of barley seed storage proteins during germination. Several Cysteine proteases have been identified in barley. One of the key enzymes, Hordeum vulgare endoprotease B2 (HvEPB2) was cloned with and w......Cysteine Proteases accounts for more than 90 % of the total proteolytic activity in the degradation of barley seed storage proteins during germination. Several Cysteine proteases have been identified in barley. One of the key enzymes, Hordeum vulgare endoprotease B2 (HvEPB2) was cloned...

  4. Soft Cysteine Signaling Network: The Functional Significance of Cysteine in Protein Function and the Soft Acids/Bases Thiol Chemistry That Facilitates Cysteine Modification.

    Science.gov (United States)

    Wible, Ryan S; Sutter, Thomas R

    2017-03-20

    The unique biophysical and electronic properties of cysteine make this molecule one of the most biologically critical amino acids in the proteome. The defining sulfur atom in cysteine is much larger than the oxygen and nitrogen atoms more commonly found in the other amino acids. As a result of its size, the valence electrons of sulfur are highly polarizable. Unique protein microenvironments favor the polarization of sulfur, thus increasing the overt reactivity of cysteine. Here, we provide a brief overview of the endogenous generation of reactive oxygen and electrophilic species and specific examples of enzymes and transcription factors in which the oxidation or covalent modification of cysteine in those proteins modulates their function. The perspective concludes with a discussion of cysteine chemistry and biophysics, the hard and soft acids and bases model, and the proposal of the Soft Cysteine Signaling Network: a hypothesis proposing the existence of a complex signaling network governed by layered chemical reactivity and cross-talk in which the chemical modification of reactive cysteine in biological networks triggers the reorganization of intracellular biochemistry to mitigate spikes in endogenous or exogenous oxidative or electrophilic stress.

  5. Residual stresses

    International Nuclear Information System (INIS)

    Sahotra, I.M.

    2006-01-01

    The principal effect of unloading a material strained into the plastic range is to create a permanent set (plastic deformation), which if restricted somehow, gives rise to a system of self-balancing within the same member or reaction balanced by other members of the structure., known as residual stresses. These stresses stay there as locked-in stresses, in the body or a part of it in the absence of any external loading. Residual stresses are induced during hot-rolling and welding differential cooling, cold-forming and extruding: cold straightening and spot heating, fabrication and forced fitting of components constraining the structure to a particular geometry. The areas which cool more quickly develop residual compressive stresses, while the slower cooling areas develop residual tensile stresses, and a self-balancing or reaction balanced system of residual stresses is formed. The phenomenon of residual stresses is the most challenging in its application in surface modification techniques determining endurance mechanism against fracture and fatigue failures. This paper discusses the mechanism of residual stresses, that how the residual stresses are fanned and what their behavior is under the action of external forces. Such as in the case of a circular bar under limit torque, rectangular beam under limt moment, reclaiming of shafts welds and peening etc. (author)

  6. Protein redox chemistry: post-translational cysteine modifications that regulate signal transduction and drug pharmacology

    Directory of Open Access Journals (Sweden)

    Revati eWani

    2014-10-01

    Full Text Available The perception of reactive oxygen species (ROS has evolved over the past decade from agents of cellular damage to secondary messengers which modify signaling proteins in physiology and the disease state (e.g. cancer. New protein targets of specific oxidation are rapidly being identified. One emerging class of redox modification occurs to the thiol side chain of cysteine residues which can produce multiple chemically-distinct alterations to the protein (e.g. sulfenic/sulfinic/sulfonic acid, disulfides. These post-translational modifications (PTM are shown to affect the protein structure and function. Because redox-sensitive proteins can traffic between subcellular compartments that have different redox environments, cysteine oxidation enables a spatio-temporal control to signaling. Understanding ramifications of these oxidative modifications to the functions of signaling proteins is crucial for understanding cellular regulation as well as for informed-drug discovery process. The effects of EGFR oxidation of Cys797 on inhibitor pharmacology are presented to illustrate the principle. Taken together, cysteine redox PTM can impact both cell biology and drug pharmacology.

  7. The unique cysteine knot regulates the pleotropic hormone leptin.

    Directory of Open Access Journals (Sweden)

    Ellinor Haglund

    Full Text Available Leptin plays a key role in regulating energy intake/expenditure, metabolism and hypertension. It folds into a four-helix bundle that binds to the extracellular receptor to initiate signaling. Our work on leptin revealed a hidden complexity in the formation of a previously un-described, cysteine-knotted topology in leptin. We hypothesized that this unique topology could offer new mechanisms in regulating the protein activity. A combination of in silico simulation and in vitro experiments was used to probe the role of the knotted topology introduced by the disulphide-bridge on leptin folding and function. Our results surprisingly show that the free energy landscape is conserved between knotted and unknotted protein, however the additional complexity added by the knot formation is structurally important. Native state analyses led to the discovery that the disulphide-bond plays an important role in receptor binding and thus mediate biological activity by local motions on distal receptor-binding sites, far removed from the disulphide-bridge. Thus, the disulphide-bridge appears to function as a point of tension that allows dissipation of stress at a distance in leptin.

  8. Functional Differentiation of Antiporter-Like Polypeptides in Complex I; a Site-Directed Mutagenesis Study of Residues Conserved in MrpA and NuoL but Not in MrpD, NuoM, and NuoN.

    Directory of Open Access Journals (Sweden)

    Eva Sperling

    Full Text Available It has long been known that the three largest subunits in the membrane domain (NuoL, NuoM and NuoN of complex I are homologous to each other, as well as to two subunits (MrpA and MrpD from a Na+/H+ antiporter, Mrp. MrpA and NuoL are more similar to each other and the same is true for MrpD and NuoN. This suggests a functional differentiation which was proven experimentally in a deletion strain model system, where NuoL could restore the loss of MrpA, but not that of MrpD and vice versa. The simplest explanation for these observations was that the MrpA and MrpD proteins are not antiporters, but rather single subunit ion channels that together form an antiporter. In this work our focus was on a set of amino acid residues in helix VIII, which are only conserved in NuoL and MrpA (but not in any of the other antiporter-like subunits. and to compare their effect on the function of these two proteins. By combining complementation studies in B. subtilis and 23Na-NMR, response of mutants to high sodium levels were tested. All of the mutants were able to cope with high salt levels; however, all but one mutation (M258I/M225I showed differences in the efficiency of cell growth and sodium efflux. Our findings showed that, although very similar in sequence, NuoL and MrpA seem to differ on the functional level. Nonetheless the studied mutations gave rise to interesting phenotypes which are of interest in complex I research.

  9. Residual stresses

    International Nuclear Information System (INIS)

    Macherauch, E.

    1978-01-01

    Residual stresses are stresses which exist in a material without the influence of external powers and moments. They come into existence when the volume of a material constantly changes its form as a consequence of mechanical, thermal, and/or chemical processes and is hindered by neighbouring volumes. Bodies with residual stress are in mechanical balance. These residual stresses can be manifested by means of all mechanical interventions disturbing this balance. Acoustical, optical, radiological, and magnetical methods involving material changes caused by residual stress can also serve for determining residual stress. Residual stresses have an ambivalent character. In technical practice, they are feared and liked at the same time. They cause trouble because they can be the cause for unexpected behaviour of construction elements. They are feared since they can cause failure, in the worst case with catastrophical consequences. They are appreciated, on the other hand, because, in many cases, they can contribute to improvements of the material behaviour under certain circumstances. But they are especially liked for their giving convenient and (this is most important) mostly uncontrollable explanations. For only in very few cases we have enough knowledge and possibilities for the objective evaluation of residual stresses. (orig.) [de

  10. Cysteine peroxidase activity in rat blood plasma | Razygraev ...

    African Journals Online (AJOL)

    The rat plasma found to be able to accelerate greatly the H2O2-dependent oxidation of cysteine. The activity was a characteristic of a protein fraction precipitated at 30—44% ammonium sulfate saturation, and the specific activity in protein fraction was significantly higher than in plasma. Cysteine:H2O2 oxidoreductase ...

  11. Antimalarial effects of vinyl sulfone cysteine proteinase inhibitors.

    OpenAIRE

    Rosenthal, P J; Olson, J E; Lee, G K; Palmer, J T; Klaus, J L; Rasnick, D

    1996-01-01

    We evaluated the antimalarial effects of vinyl sulfone cysteine proteinase inhibitors. A number of vinyl sulfones strongly inhibited falcipain, a Plasmodium falciparum cysteine proteinase that is a critical hemoglobinase. In studies of cultured parasites, nanomolar concentrations of three vinyl sulfones inhibited parasite hemoglobin degradation, metabolic activity, and development. The antimalarial effects correlated with the inhibition of falcipain. Our results suggest that vinyl sulfones or...

  12. Lysosomal cysteine peptidases - Molecules signaling tumor cell death and survival.

    Science.gov (United States)

    Pišlar, Anja; Perišić Nanut, Milica; Kos, Janko

    2015-12-01

    Lysosomal cysteine peptidases - cysteine cathepsins - are general intracellular protein-degrading enzymes that control also a variety of specific physiological processes. They can trigger irreversible events leading to signal transduction and activation of signaling pathways, resulting in cell survival and proliferation or cell death. In cancer cells, lysosomal cysteine peptidases are involved in multiple processes during malignant progression. Their translocation from the endosomal/lysosomal pathway to nucleus, cytoplasm, plasma membrane and extracellular space enables the activation and remodeling of a variety of tumor promoting proteins. Thus, lysosomal cysteine peptidases interfere with cytokine/chemokine signaling, regulate cell adhesion and migration and endocytosis, are involved in the antitumor immune response and apoptosis, and promote cell invasion, angiogenesis and metastasis. Further, lysosomal cysteine peptidases modify growth factors and receptors involved in tyrosine kinase dependent pathways such as MAPK, Akt and JNK, thus representing key signaling tools for the activation of tumor cell growth and proliferation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Overexpression of an Arabidopsis cysteine-rich receptor-like protein kinase, CRK5, enhances abscisic acid sensitivity and confers drought tolerance

    Science.gov (United States)

    Lu, Kai; Liang, Shan; Wu, Zhen; Bi, Chao; Yu, Yong-Tao; Wang, Xiao-Fang; Zhang, Da-Peng

    2016-01-01

    Receptor-like kinases (RLKs) have been reported to regulate many developmental and defense process, but only a few members have been functionally characterized. In the present study, our observations suggest that one of the RLKs, a membrane-localized cysteine-rich receptor-like protein kinase, CRK5, is involved in abscisic acid (ABA) signaling in Arabidopsis thaliana. Overexpression of CRK5 increases ABA sensitivity in ABA-induced early seedling growth arrest and promotion of stomatal closure and inhibition of stomatal opening. Interestingly, and importantly, overexpression of CRK5 enhances plant drought tolerance without affecting plant growth at the mature stages and plant productivity. Transgenic lines overexpressing a mutated form of CRK5, CRK5 K372E with the change of the 372nd conserved amino acid residue from lysine to glutamic acid in its kinase domain, result in wild-type ABA and drought responses, supporting the role of CRK5 in ABA signaling. The loss-of-function mutation of the CRK5 gene does not affect the ABA response, while overexpression of two homologs of CRK5, CRK4 and CRK19, confers ABA responses, suggesting that these CRK members function redundantly. We further showed that WRKY18, WRKY40 and WRKY60 transcription factors repress the expression of CRK5, and that CRK5 likely functions upstream of ABI2 in ABA signaling. These findings help in understanding the complex ABA signaling network. PMID:27406784

  14. Cysteine sulfoxide derivatives in Petiveria alliacea.

    Science.gov (United States)

    Kubec, R; Musah, R A

    2001-11-01

    Two diastereomers of S-benzyl-L-cysteine sulfoxide have been isolated from fresh roots of Petiveria alliacea. Their structures and absolute configurations have been determined by NMR, MALDI-HRMS, IR and CD spectroscopy and confirmed by comparison with authentic compounds. Both the R(S) and S(S) diastereomers of the sulfoxide are present in all parts of the plant (root, stem, and leaves) with the latter diastereomer being predominant. Their total content greatly varied in different parts of the plant between 0.07 and 2.97 mg g(-1) fr. wt, being by far the highest in the root. S-Benzylcysteine has also been detected in trace amounts (<10 microg g(-1) fr. wt) in all parts of the plant. This represents the first report of the presence of S-benzylcysteine derivatives in nature.

  15. Retaining in-gel zymographic activity of cysteine proteases via a cysteine-supplemented running buffer.

    Science.gov (United States)

    Vootukuri Reddy, Sreekanth; Philpott, Mike P; Trigiante, Giuseppe

    2016-10-01

    Zymography is a powerful technique to separate and identify different enzymatic activities on a standard acrylamide gel. For oxidation prone enzymes such as cysteine proteases however, the oxidizing species generated by electrolysis of the gel running buffer may result in partial or complete inactivation, thus compromising the final readout. This can be only partially remedied by subsequent treatment of the gel with reducing agents. We demonstrate the generation of reactive oxidizing species during electrophoresis and discovered that supplementation of the gel running buffer with a minimum of 5 mM cysteine prevents enzyme inactivation and allows retention of proteolytic activity as measured by zymography on model substrate N α-benzoyl-l-arginine p-nitroanilide, without at the same time altering the mobilities of the gel proteins. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Simultaneous electrochemical determination of L-cysteine and L-cysteine disulfide at carbon ionic liquid electrode.

    Science.gov (United States)

    Safavi, Afsaneh; Ahmadi, Raheleh; Mahyari, Farzaneh Aghakhani

    2014-04-01

    A linear sweep voltammetric method is used for direct simultaneous determination of L-cysteine and L-cysteine disulfide (cystine) based on carbon ionic liquid electrode. With carbon ionic liquid electrode as a high performance electrode, two oxidation peaks for L-cysteine (0.62 V) and L-cysteine disulfide (1.3 V) were observed with a significant separation of about 680 mV (vs. Ag/AgCl) in phosphate buffer solution (pH 6.0). The linear ranges were obtained as 1.0-450 and 5.0-700 μM and detection limits were estimated to be 0.298 and 4.258 μM for L-cysteine and L-cysteine disulfide, respectively. This composite electrode was applied for simultaneous determination of L-cysteine and L-cysteine disulfide in two real samples, artificial urine and nutrient broth. Satisfactory results were obtained which clearly indicate the applicability of the proposed electrode for simultaneous determination of these compounds in complex matrices.

  17. CHARACTERIZATION OF DANSYLATED CYSTEINE, GLUTATHIONE DISULFIDE, CYSTEINE AND CYSTINE BY NARROW BORE LIQUID CHROMATOGRAPHY/ELECTROSPRAY IONIZATION MASS SPECTROMETRY

    Science.gov (United States)

    A method using reversed phase high performance liquid chromatography/electrospray ionization-mass spectrometric (RP-LC/ESI-MS) method has been developed to confirm the identity of dansylated derivatives of cysteine and glutathione, and their respective dimers. Cysteine, GSH, CSSC...

  18. Correction: β-Amyrin synthase from Euphorbia tirucalli L. functional analyses of the highly conserved aromatic residues Phe413, Tyr259 and Trp257 disclose the importance of the appropriate steric bulk, and cation-π and CH-π interactions for the efficient catalytic action of the polyolefin cyclization cascade.

    Science.gov (United States)

    Ito, Ryousuke; Nakada, Chika; Hoshino, Tsutomu

    2017-01-18

    Correction for 'β-Amyrin synthase from Euphorbia tirucalli L. functional analyses of the highly conserved aromatic residues Phe413, Tyr259 and Trp257 disclose the importance of the appropriate steric bulk, and cation-π and CH-π interactions for the efficient catalytic action of the polyolefin cyclization cascade' by Ryousuke Ito et al., Org. Biomol. Chem., 2017, 15, 177-188.

  19. Cysteine-Rich Peptide Family with Unusual Disulfide Connectivity from Jasminum sambac.

    Science.gov (United States)

    Kumari, Geeta; Serra, Aida; Shin, Joon; Nguyen, Phuong Q T; Sze, Siu Kwan; Yoon, Ho Sup; Tam, James P

    2015-11-25

    Cysteine-rich peptides (CRPs) are natural products with privileged peptidyl structures that represent a potentially rich source of bioactive compounds. Here, the discovery and characterization of a novel plant CRP family, jasmintides from Jasminum sambac of the Oleaceae family, are described. Two 27-amino acid jasmintides (jS1 and jS2) were identified at the gene and protein levels. Disulfide bond mapping of jS1 by mass spectrometry and its confirmation by NMR spectroscopy revealed disulfide bond connectivity of C-1-C-5, C-2-C-4, and C-3-C-6, a cystine motif that has not been reported in plant CRPs. Structural determination showed that jS1 displays a well-defined structure framed by three short antiparallel β-sheets. Genomic analysis showed that jasmintides share a three-domain precursor arrangement with a C-terminal mature domain preceded by a long pro-domain of 46 residues and an intron cleavage site between the signal sequence and pro-domain. The compact cysteine-rich structure together with an N-terminal pyroglutamic acid residue confers jasmintides high resistance to heat and enzymatic degradation, including exopeptidase treatment. Collectively, these results reveal a new plant CRP structure with an unusual cystine connectivity, which could be useful as a scaffold for designing peptide drugs.

  20. Cysteine 893 is a target of regulatory thiol modifications of GluA1 AMPA receptors.

    Directory of Open Access Journals (Sweden)

    Lotta von Ossowski

    Full Text Available Recent studies indicate that glutamatergic signaling involves, and is regulated by, thiol modifying and redox-active compounds. In this study, we examined the role of a reactive cysteine residue, Cys-893, in the cytosolic C-terminal tail of GluA1 AMPA receptor as a potential regulatory target. Elimination of the thiol function by substitution of serine for Cys-893 led to increased steady-state expression level and strongly reduced interaction with SAP97, a major cytosolic interaction partner of GluA1 C-terminus. Moreover, we found that of the three cysteine residues in GluA1 C-terminal tail, Cys-893 is the predominant target for S-nitrosylation induced by exogenous nitric oxide donors in cultured cells and lysates. Co-precipitation experiments provided evidence for native association of SAP97 with neuronal nitric oxide synthase (nNOS and for the potential coupling of Ca2+-permeable GluA1 receptors with nNOS via SAP97. Our results show that Cys-893 can serve as a molecular target for regulatory thiol modifications of GluA1 receptors, including the effects of nitric oxide.

  1. Probes of the catalytic site of cysteine dioxygenase.

    Science.gov (United States)

    Chai, Sergio C; Bruyere, John R; Maroney, Michael J

    2006-06-09

    The first major step of cysteine catabolism, the oxidation of cysteine to cysteine sulfinic acid, is catalyzed by cysteine dioxygenase (CDO). In the present work, we utilize recombinant rat liver CDO and cysteine derivatives to elucidate structural parameters involved in substrate recognition and x-ray absorption spectroscopy to probe the interaction of the active site iron center with cysteine. Kinetic studies using cysteine structural analogs show that most are inhibitors and that a terminal functional group bearing a negative charge (e.g. a carboxylate) is required for binding. The substrate-binding site has no stringent restrictions with respect to the size of the amino acid. Lack of the amino or carboxyl groups at the alpha-carbon does not prevent the molecules from interacting with the active site. In fact, cysteamine is shown to be a potent activator of the enzyme without being a substrate. CDO was also rendered inactive upon complexation with the metal-binding inhibitors azide and cyanide. Unlike many non-heme iron dioxygenases that employ alpha-keto acids as cofactors, CDO was shown to be the only dioxygenase known to be inhibited by alpha-ketoglutarate.

  2. L-Cysteine metabolism and its nutritional implications.

    Science.gov (United States)

    Yin, Jie; Ren, Wenkai; Yang, Guan; Duan, Jielin; Huang, Xingguo; Fang, Rejun; Li, Chongyong; Li, Tiejun; Yin, Yulong; Hou, Yongqing; Kim, Sung Woo; Wu, Guoyao

    2016-01-01

    L-Cysteine is a nutritionally semiessential amino acid and is present mainly in the form of L-cystine in the extracellular space. With the help of a transport system, extracellular L-cystine crosses the plasma membrane and is reduced to L-cysteine within cells by thioredoxin and reduced glutathione (GSH). Intracellular L-cysteine plays an important role in cellular homeostasis as a precursor for protein synthesis, and for production of GSH, hydrogen sulfide (H(2)S), and taurine. L-Cysteine-dependent synthesis of GSH has been investigated in many pathological conditions, while the pathway for L-cysteine metabolism to form H(2)S has received little attention with regard to prevention and treatment of disease in humans. The main objective of this review is to highlight the metabolic pathways of L-cysteine catabolism to GSH, H(2)S, and taurine, with special emphasis on therapeutic and nutritional use of L-cysteine to improve the health and well-being of animals and humans. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Overexpression of Catalase Diminishes Oxidative Cysteine Modifications of Cardiac Proteins.

    Directory of Open Access Journals (Sweden)

    Chunxiang Yao

    Full Text Available Reactive protein cysteine thiolates are instrumental in redox regulation. Oxidants, such as hydrogen peroxide (H2O2, react with thiolates to form oxidative post-translational modifications, enabling physiological redox signaling. Cardiac disease and aging are associated with oxidative stress which can impair redox signaling by altering essential cysteine thiolates. We previously found that cardiac-specific overexpression of catalase (Cat, an enzyme that detoxifies excess H2O2, protected from oxidative stress and delayed cardiac aging in mice. Using redox proteomics and systems biology, we sought to identify the cysteines that could play a key role in cardiac disease and aging. With a 'Tandem Mass Tag' (TMT labeling strategy and mass spectrometry, we investigated differential reversible cysteine oxidation in the cardiac proteome of wild type and Cat transgenic (Tg mice. Reversible cysteine oxidation was measured as thiol occupancy, the ratio of total available versus reversibly oxidized cysteine thiols. Catalase overexpression globally decreased thiol occupancy by ≥1.3 fold in 82 proteins, including numerous mitochondrial and contractile proteins. Systems biology analysis assigned the majority of proteins with differentially modified thiols in Cat Tg mice to pathways of aging and cardiac disease, including cellular stress response, proteostasis, and apoptosis. In addition, Cat Tg mice exhibited diminished protein glutathione adducts and decreased H2O2 production from mitochondrial complex I and II, suggesting improved function of cardiac mitochondria. In conclusion, our data suggest that catalase may alleviate cardiac disease and aging by moderating global protein cysteine thiol oxidation.

  4. SNOSite: exploiting maximal dependence decomposition to identify cysteine S-nitrosylation with substrate site specificity.

    Directory of Open Access Journals (Sweden)

    Tzong-Yi Lee

    Full Text Available S-nitrosylation, the covalent attachment of a nitric oxide to (NO the sulfur atom of cysteine, is a selective and reversible protein post-translational modification (PTM that regulates protein activity, localization, and stability. Despite its implication in the regulation of protein functions and cell signaling, the substrate specificity of cysteine S-nitrosylation remains unknown. Based on a total of 586 experimentally identified S-nitrosylation sites from SNAP/L-cysteine-stimulated mouse endothelial cells, this work presents an informatics investigation on S-nitrosylation sites including structural factors such as the flanking amino acids composition, the accessible surface area (ASA and physicochemical properties, i.e. positive charge and side chain interaction parameter. Due to the difficulty to obtain the conserved motifs by conventional motif analysis, maximal dependence decomposition (MDD has been applied to obtain statistically significant conserved motifs. Support vector machine (SVM is applied to generate predictive model for each MDD-clustered motif. According to five-fold cross-validation, the MDD-clustered SVMs could achieve an accuracy of 0.902, and provides a promising performance in an independent test set. The effectiveness of the model was demonstrated on the correct identification of previously reported S-nitrosylation sites of Bos taurus dimethylarginine dimethylaminohydrolase 1 (DDAH1 and human hemoglobin subunit beta (HBB. Finally, the MDD-clustered model was adopted to construct an effective web-based tool, named SNOSite (http://csb.cse.yzu.edu.tw/SNOSite/, for identifying S-nitrosylation sites on the uncharacterized protein sequences.

  5. Subcellular distribution of glutathione and cysteine in cyanobacteria.

    Science.gov (United States)

    Zechmann, Bernd; Tomasić, Ana; Horvat, Lucija; Fulgosi, Hrvoje

    2010-10-01

    Glutathione plays numerous important functions in eukaryotic and prokaryotic cells. Whereas it can be found in virtually all eukaryotic cells, its production in prokaryotes is restricted to cyanobacteria and proteobacteria and a few strains of gram-positive bacteria. In bacteria, it is involved in the protection against reactive oxygen species (ROS), osmotic shock, acidic conditions, toxic chemicals, and heavy metals. Glutathione synthesis in bacteria takes place in two steps out of cysteine, glutamate, and glycine. Cysteine is the limiting factor for glutathione biosynthesis which can be especially crucial for cyanobacteria, which rely on both the sufficient sulfur supply from the growth media and on the protection of glutathione against ROS that are produced during photosynthesis. In this study, we report a method that allows detection and visualization of the subcellular distribution of glutathione in Synechocystis sp. This method is based on immunogold cytochemistry with glutathione and cysteine antisera and computer-supported transmission electron microscopy. Labeling of glutathione and cysteine was restricted to the cytosol and interthylakoidal spaces. Glutathione and cysteine could not be detected in carboxysomes, cyanophycin granules, cell walls, intrathylakoidal spaces, periplasm, and vacuoles. The accuracy of the glutathione and cysteine labeling is supported by two observations. First, preadsorption of the antiglutathione and anticysteine antisera with glutathione and cysteine, respectively, reduced the density of the gold particles to background levels. Second, labeling of glutathione and cysteine was strongly decreased by 98.5% and 100%, respectively, in Synechocystis sp. cells grown on media without sulfur. This study indicates a strong similarity of the subcellular distribution of glutathione and cysteine in cyanobacteria and plastids of plants and provides a deeper insight into glutathione metabolism in bacteria.

  6. Effect of (L)-cysteine on acetaldehyde self-administration.

    Science.gov (United States)

    Peana, Alessandra T; Muggironi, Giulia; Fois, Giulia R; Zinellu, Manuel; Sirca, Donatella; Diana, Marco

    2012-08-01

    Acetaldehyde (ACD), the first metabolite of ethanol, has been implicated in several behavioural actions of alcohol, including its reinforcing effects. Recently, we reported that l-cysteine, a sequestrating agent of ACD, reduced oral ethanol self-administration and that ACD was orally self-administered. This study examined the effects of l-cysteine pre-treatment during the acquisition and maintenance phases of ACD (0.2%) self-administration as well as on the deprivation effect after ACD extinction and on a progressive ratio (PR) schedule of reinforcement. In a separate PR schedule of reinforcement, the effect of l-cysteine was assessed on the break-point produced by ethanol (10%). Furthermore, we tested the effect of l-cysteine on saccharin (0.2%) reinforcement. Wistar rats were trained to self-administer ACD by nose poking on a fixed ratio (FR1) schedule in 30-min daily sessions. Responses on an active nose-poke caused delivery of ACD solution, whereas responses on an inactive nose-poke had no consequences. l-cysteine reduced the acquisition (40 mg/kg), the maintenance and the deprivation effect (100 mg/kg) of ACD self-administration. Furthermore, at the same dose, l-cysteine (120 mg/kg) decreased both ACD and ethanol break point. In addition, l-cysteine was unable to suppress the different responses for saccharin, suggesting that its effect did not relate to an unspecific decrease in a general motivational state. Compared to saline, l-cysteine did not modify responses on inactive nose-pokes, suggesting an absence of a non-specific behavioural activation. Taken together, these results could support the hypotheses that ACD possesses reinforcing properties and l-cysteine reduces motivation to self-administer ACD. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Solid residues

    International Nuclear Information System (INIS)

    Mulder, E.; Duin, P.J. van; Grootenboer, G.J.

    1995-01-01

    A summary is presented of the many investigations that have been done on solid residues of atmospheric fluid bed combustion (AFBC). These residues are bed ash, cyclone ash and bag filter ash. Physical and chemical properties are discussed and then the various uses of residues (in fillers, bricks, gravel, and for recovery of aluminium) are summarised. Toxicological properties of fly ash and stack ash are discussed as are risks of pneumoconiosis for workers handling fly ash, and contamination of water by ashes. On the basis of present information it is concluded that risks to public health from exposure to emissions of coal fly ash from AFBC appear small or negligible as are health risk to workers in the coal fly ash processing industry. 35 refs., 5 figs., 12 tabs

  8. Developing novel anthelmintics from plant cysteine proteinases

    Directory of Open Access Journals (Sweden)

    Stepek Gillian

    2008-09-01

    Full Text Available Abstract Intestinal helminth infections of livestock and humans are predominantly controlled by treatment with three classes of synthetic drugs, but some livestock nematodes have now developed resistance to all three classes and there are signs that human hookworms are becoming less responsive to the two classes (benzimidazoles and the nicotinic acetylcholine agonists that are licensed for treatment of humans. New anthelmintics are urgently needed, and whilst development of new synthetic drugs is ongoing, it is slow and there are no signs yet that novel compounds operating through different modes of action, will be available on the market in the current decade. The development of naturally-occurring compounds as medicines for human use and for treatment of animals is fraught with problems. In this paper we review the current status of cysteine proteinases from fruits and protective plant latices as novel anthelmintics, we consider some of the problems inherent in taking laboratory findings and those derived from folk-medicine to the market and we suggest that there is a wealth of new compounds still to be discovered that could be harvested to benefit humans and livestock.

  9. Cloning and characterization of a novel cysteine protease gene ...

    Indian Academy of Sciences (India)

    PRAKASH KUMAR

    Cysteine proteases can be found in the animal and plant kingdoms as well as in some viruses and bacteria. They have been implemented in many ..... in developing resistance against pathogens and insects in other crops. Acknowledgments.

  10. Potential role of cysteine and methionine in the protection against hormonal imbalance and mutagenicity induced by furazolidone in female rats

    International Nuclear Information System (INIS)

    Ahmed, Hanaa H.; El-Aziem, Sekena H. Abd; Abdel-Wahhab, Mosaad A.

    2008-01-01

    The use of nitrofurans as veterinary drugs has been banned in the EU since 1993 due to doubts on the safety of the protein-bound residues of these drugs in edible products. Furazolidone (FUZ) is a nitrofuran drug, which has been used for many years as an antibacterial drug in veterinary practice. The aim of the current study is to investigate the role of L-cysteine and L-methionine in the protection against hormonal imbalance and the genotoxicity induced by FUZ using the micronucleus (MN) assay and random amplified polymorphism DNA (RAPD-PCR) analysis in female rats. Forty female Sprague-Dawley rats were divided into four groups included the untreated control group; a group treated with FUZ (300 mg/kg b.w.); a group treated with a mixture of L-cysteine (300 mg/kg b.w.) and L-methionine (42.8 mg/kg b.w.) and a group treated with FUZ plus the mixture of L-cysteine and L-methionine for 10 days. The results indicated that FUZ induced hormonal disturbances involving thyroid, ovarian and adrenal hormones. Moreover, FUZ increased the micronucleus formation and induced changes in polymorphic band patterns. The combined treatment with FUZ and the mixture of L-cysteine and L-methionine succeeded to prevent or diminish the endocrine disturbance and the clastogenic effects of FUZ. The current study is casting new light on the complex mechanisms underlying the ameliorating action of dietary L-cysteine and L-methionine against FUZ toxicity in experimental animals

  11. Plasmodium cysteine repeat modular proteins 1-4: complex proteins with roles throughout the malaria parasite life cycle.

    Science.gov (United States)

    Thompson, Joanne; Fernandez-Reyes, Delmiro; Sharling, Lisa; Moore, Sally G; Eling, Wijnand M; Kyes, Sue A; Newbold, Christopher I; Kafatos, Fotis C; Janse, Chris J; Waters, Andrew P

    2007-06-01

    The Cysteine Repeat Modular Proteins (PCRMP1-4) of Plasmodium, are encoded by a small gene family that is conserved in malaria and other Apicomplexan parasites. They are very large, predicted surface proteins with multipass transmembrane domains containing motifs that are conserved within families of cysteine-rich, predicted surface proteins in a range of unicellular eukaryotes, and a unique combination of protein-binding motifs, including a >100 kDa cysteine-rich modular region, an epidermal growth factor-like domain and a Kringle domain. PCRMP1 and 2 are expressed in life cycle stages in both the mosquito and vertebrate. They colocalize with PfEMP1 (P. falciparum Erythrocyte Membrane Antigen-1) during its export from P. falciparum blood-stage parasites and are exposed on the surface of haemolymph- and salivary gland-sporozoites in the mosquito, consistent with a role in host tissue targeting and invasion. Gene disruption of pcrmp1 and 2 in the rodent malaria model, P. berghei, demonstrated that both are essential for transmission of the parasite from the mosquito to the mouse and has established their discrete and important roles in sporozoite targeting to the mosquito salivary gland. The unprecedented expression pattern and structural features of the PCRMPs thus suggest a variety of roles mediating host-parasite interactions throughout the parasite life cycle.

  12. Cysteine homeostasis plays an essential role in plant immunity.

    Science.gov (United States)

    Álvarez, Consolación; Bermúdez, M Ángeles; Romero, Luis C; Gotor, Cecilia; García, Irene

    2012-01-01

    Cysteine is the metabolic precursor of essential biomolecules such as vitamins, cofactors, antioxidants and many defense compounds. The last step of cysteine metabolism is catalysed by O-acetylserine(thiol)lyase (OASTL), which incorporates reduced sulfur into O-acetylserine to produce cysteine. In Arabidopsis thaliana, the main OASTL isoform OAS-A1 and the cytosolic desulfhydrase DES1, which degrades cysteine, contribute to the cytosolic cysteine homeostasis. • Meta-analysis of the transcriptomes of knockout plants for OAS-A1 and for DES1 show a high correlation with the biotic stress series in both cases. • The study of the response of knockout mutants to plant pathogens shows that des1 mutants behave as constitutive systemic acquired resistance mutants, with high resistance to biotrophic and necrotrophic pathogens, salicylic acid accumulation and WRKY54 and PR1 induction, while oas-a1 knockout mutants are more sensitive to biotrophic and necrotrophic pathogens. However, oas-a1 knockout mutants lack the hypersensitive response associated with the effector-triggered immunity elicited by Pseudomonas syringae pv. tomato DC3000 avrRpm1. • Our results highlight the role of cysteine as a crucial metabolite in the plant immune response. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  13. Synthesis, antioxidative and whitening effects of novel cysteine derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Ji Hoon; Kim, Kyoung Mi; Jeong, Yoon Ju; Park, Young Min; Lee, Jae Young; Park, Soo Nam [Dept. of Fine Chemistry, Cosmetic R and D Center, Cosmetic Industry Coupled Collaboration Center, Seoul National University of Science and Technology, Seoul (Korea, Republic of); Park, Jino [Daebong LS. Ltd, Incheon (Korea, Republic of)

    2017-01-15

    Recently, development of biocompatibility functional cosmetic agents as antioxidant or whitening agent has increased. In this study, synthetic cysteine derivatives (DBLS-21, -24, and -33) were developed containing syringic acid and cysteine moieties (l-cysteine ethyl ester, N-acetyl cysteine methyl ester, and N-acetyl cysteine ethyl ester), and their antioxidative and whitening activities were evaluated. The cellular protective effect (τ{sub 50}) of DBLS-21 was 51.1 min at 50 μM on {sup 1}O{sub 2} -induced hemolysis of erythrocytes. This activity was slightly higher than that of α-tocopherol (43.6 min) as a lipophilic antioxidant. In the melanogenesis inhibitory effect, DBLS-21, -24, and -33 was 1.6-, 1.8-, and 2.5-fold higher than arbutin, respectively. In particular, DBLS-21 and -33 was 112.8- and 6.1-fold higher than arbutin, respectively (293.4 μM) on tyrosinase inhibition activity (IC{sub 50} ). But DBLS-24 had no tyrosinase inhibitory activity. These results suggest that cysteine derivatives possess potential for use as an antioxidant agent (DBLS-21) and whitening agents (all derivatives) in cosmetics.

  14. Synthesis, antioxidative and whitening effects of novel cysteine derivatives

    International Nuclear Information System (INIS)

    Ha, Ji Hoon; Kim, Kyoung Mi; Jeong, Yoon Ju; Park, Young Min; Lee, Jae Young; Park, Soo Nam; Park, Jino

    2017-01-01

    Recently, development of biocompatibility functional cosmetic agents as antioxidant or whitening agent has increased. In this study, synthetic cysteine derivatives (DBLS-21, -24, and -33) were developed containing syringic acid and cysteine moieties (l-cysteine ethyl ester, N-acetyl cysteine methyl ester, and N-acetyl cysteine ethyl ester), and their antioxidative and whitening activities were evaluated. The cellular protective effect (τ_5_0) of DBLS-21 was 51.1 min at 50 μM on "1O_2 -induced hemolysis of erythrocytes. This activity was slightly higher than that of α-tocopherol (43.6 min) as a lipophilic antioxidant. In the melanogenesis inhibitory effect, DBLS-21, -24, and -33 was 1.6-, 1.8-, and 2.5-fold higher than arbutin, respectively. In particular, DBLS-21 and -33 was 112.8- and 6.1-fold higher than arbutin, respectively (293.4 μM) on tyrosinase inhibition activity (IC_5_0 ). But DBLS-24 had no tyrosinase inhibitory activity. These results suggest that cysteine derivatives possess potential for use as an antioxidant agent (DBLS-21) and whitening agents (all derivatives) in cosmetics

  15. Residual basins

    International Nuclear Information System (INIS)

    D'Elboux, C.V.; Paiva, I.B.

    1980-01-01

    Exploration for uranium carried out over a major portion of the Rio Grande do Sul Shield has revealed a number of small residual basins developed along glacially eroded channels of pre-Permian age. Mineralization of uranium occurs in two distinct sedimentary units. The lower unit consists of rhythmites overlain by a sequence of black shales, siltstones and coal seams, while the upper one is dominated by sandstones of probable fluvial origin. (Author) [pt

  16. Sulfone-stabilized carbanions for the reversible covalent capture of a posttranslationally-generated cysteine oxoform found in protein tyrosine phosphatase 1B (PTP1B).

    Science.gov (United States)

    Parsons, Zachary D; Ruddraraju, Kasi Viswanatharaju; Santo, Nicholas; Gates, Kent S

    2016-06-15

    Redox regulation of protein tyrosine phosphatase 1B (PTP1B) involves oxidative conversion of the active site cysteine thiolate into an electrophilic sulfenyl amide residue. Reduction of the sulfenyl amide by biological thiols regenerates the native cysteine residue. Here we explored fundamental chemical reactions that may enable covalent capture of the sulfenyl amide residue in oxidized PTP1B. Various sulfone-containing carbon acids were found to react readily with a model peptide sulfenyl amide via attack of the sulfonyl carbanion on the electrophilic sulfur center in the sulfenyl amide. Both the products and the rates of these reactions were characterized. The results suggest that capture of a peptide sulfenyl amide residue by sulfone-stabilized carbanions can slow, but not completely prevent, thiol-mediated generation of the corresponding cysteine-containing peptide. Sulfone-containing carbon acids may be useful components in the construction of agents that knock down PTP1B activity in cells via transient covalent capture of the sulfenyl amide oxoform generated during insulin signaling processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Bmcystatin, a cysteine proteinase inhibitor characterized from the tick Boophilus microplus

    International Nuclear Information System (INIS)

    Lima, Cassia A.; Sasaki, Sergio D.; Tanaka, Aparecida S.

    2006-01-01

    The bovine tick Rhipicephalus (Boophilus) microplus is a blood-sucking animal, which is responsible for Babesia spp and Anaplasma marginale transmission for cattle. From a B. microplus fat body cDNA library, 465 selected clones were sequenced randomly and resulted in 60 Contigs. An open reading frame (ORF) contains 98 amino acids named Bmcystatin, due to 70% amino acid identity to a classical type 1 cystatin from Ixodes scapularis tick (GenBank Accession No. DQ066227). The Bmcystatin amino acid sequence analysis showed two cysteine residues, theoretical pI of 5.92 and M r of 11kDa. Bmcystatin gene was cloned in pET 26b vector and the protein expressed using bacteria Escherichia coli BL21 SI. Recombinant Bmcystatin (rBmcystatin) purified by affinity chromatography on Ni-NTA-agarose column and ionic exchange chromatography on HiTrap Q column presented molecular mass of 11kDa, by SDS-PAGE and the N-terminal amino acid sequenced revealed unprocessed N-terminal containing part of pelB signal sequence. Purified rBmcystatin showed to be a C1 cysteine peptidase inhibitor with K i value of 0.1 and 0.6nM for human cathepsin L and VTDCE (vitellin degrading cysteine endopeptidase), respectively. The rBmcystatin expression analyzed by semi-quantitative RT-PCR confirmed the amplification of a specific DNA sequence (294bp) in the fat body and ovary cDNA preparation. On the other hand, a protein band was detected in the fat body, ovary, and the salivary gland extracts using anti-Bmcystatin antibody by Western blot. The present results suggest a possible role of Bmcystatin in the ovary, even though the gene was cloned from the fat body, which could be another site of this protein synthesis

  18. Bleogens: Cactus-Derived Anti-Candida Cysteine-Rich Peptides with Three Different Precursor Arrangements

    Directory of Open Access Journals (Sweden)

    Shining Loo

    2017-12-01

    Full Text Available Cysteine-rich peptides (CRPs play important host-defense roles in plants. However, information concerning CRPs in the Cactaceae (cactus family is limited, with only a single cactus-derived CRP described to date. Here, we report the identification of 15 novel CRPs with three different precursor architectures, bleogens pB1-15 from Pereskia bleo of the Cactaceae family. By combining proteomic and transcriptomic methods, we showed that the prototype, bleogen pB1, contained 36 amino acid residues, a six-cysteine motif typical of the six-cysteine-hevein-like peptide (6C-HLP family, and a type I two-domain precursor consisting of an endoplasmic reticulum (ER and a mature domain. In contrast, the precursors of the other 14 bleogens contained a type II three-domain architecture with a propeptide domain inserted between the ER and the mature bleogen domain. Four of these 14 bleogens display a third type of architecture with a tandemly repeating bleogen domain. A search of the Onekp database revealed that <1% plant species possess three different precursor architectures for the biosynthesis of 6C-HLPs, including Lophophora williamsii, Pereskia aculeate, Portulaca cryptopetala, Portulaca oleracea, Portulaca suffruticosa, and Talinum sp. NMR analysis confirmed that bleogen pB1 has cystine-knot disulfide connectivity as well as a two-beta-sheet and a four-loop structural fold that is similar to other 6C-HLPs. Sequence analysis, structural studies, and in silico modeling revealed that bleogen pB1 has a cation-polar-cation motif, a signature heparin-binding motif that was confirmed by heparin affinity chromatography. Cell-based assays showed that bleogen pB1 is non-toxic to mammalian cells but functions as an anti-Candida peptide. Taken together, our findings provide insight into the occurrence, functions and precursor architectures of CRPs in the cactus family.

  19. Mechanisms of mono- and poly-ubiquitination: Ubiquitination specificity depends on compatibility between the E2 catalytic core and amino acid residues proximal to the lysine

    Directory of Open Access Journals (Sweden)

    Sadowski Martin

    2010-08-01

    Full Text Available Abstract Ubiquitination involves the attachment of ubiquitin to lysine residues on substrate proteins or itself, which can result in protein monoubiquitination or polyubiquitination. Ubiquitin attachment to different lysine residues can generate diverse substrate-ubiquitin structures, targeting proteins to different fates. The mechanisms of lysine selection are not well understood. Ubiquitination by the largest group of E3 ligases, the RING-family E3 s, is catalyzed through co-operation between the non-catalytic ubiquitin-ligase (E3 and the ubiquitin-conjugating enzyme (E2, where the RING E3 binds the substrate and the E2 catalyzes ubiquitin transfer. Previous studies suggest that ubiquitination sites are selected by E3-mediated positioning of the lysine toward the E2 active site. Ultimately, at a catalytic level, ubiquitination of lysine residues within the substrate or ubiquitin occurs by nucleophilic attack of the lysine residue on the thioester bond linking the E2 catalytic cysteine to ubiquitin. One of the best studied RING E3/E2 complexes is the Skp1/Cul1/F box protein complex, SCFCdc4, and its cognate E2, Cdc34, which target the CDK inhibitor Sic1 for K48-linked polyubiquitination, leading to its proteasomal degradation. Our recent studies of this model system demonstrated that residues surrounding Sic1 lysines or lysine 48 in ubiquitin are critical for ubiquitination. This sequence-dependence is linked to evolutionarily conserved key residues in the catalytic region of Cdc34 and can determine if Sic1 is mono- or poly-ubiquitinated. Our studies indicate that amino acid determinants in the Cdc34 catalytic region and their compatibility to those surrounding acceptor lysine residues play important roles in lysine selection. This may represent a general mechanism in directing the mode of ubiquitination in E2 s.

  20. On the Dynamical Behavior of the Cysteine Dioxygenase-l-Cysteine Complex in the Presence of Free Dioxygen and l-Cysteine.

    Science.gov (United States)

    Pietra, Francesco

    2017-11-01

    In this work, viable models of cysteine dioxygenase (CDO) and its complex with l-cysteine dianion were built for the first time, under strict adherence to the crystal structure from X-ray diffraction studies, for all atom molecular dynamics (MD). Based on the CHARMM36 FF, the active site, featuring an octahedral dummy Fe(II) model, allowed us observing water exchange, which would have escaped attention with the more popular bonded models. Free dioxygen (O 2 ) and l-cysteine, added at the active site, could be observed being expelled toward the solvating medium under Random Accelerated Molecular Dynamics (RAMD) along major and minor pathways. Correspondingly, free dioxygen (O 2 ), added to the solvating medium, could be observed to follow the same above pathways in getting to the active site under unbiased MD. For the bulky l-cysteine, 600 ns of trajectory were insufficient for protein penetration, and the molecule was stuck at the protein borders. These models pave the way to free energy studies of ligand associations, devised to better clarify how this cardinal enzyme behaves in human metabolism. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  1. A cysteine protease inhibitor of plasmodium berghei is essential for exo-erythrocytic development.

    Directory of Open Access Journals (Sweden)

    Christine Lehmann

    2014-08-01

    Full Text Available Plasmodium parasites express a potent inhibitor of cysteine proteases (ICP throughout their life cycle. To analyze the role of ICP in different life cycle stages, we generated a stage-specific knockout of the Plasmodium berghei ICP (PbICP. Excision of the pbicb gene occurred in infective sporozoites and resulted in impaired sporozoite invasion of hepatocytes, despite residual PbICP protein being detectable in sporozoites. The vast majority of these parasites invading a cultured hepatocyte cell line did not develop to mature liver stages, but the few that successfully developed hepatic merozoites were able to initiate a blood stage infection in mice. These blood stage parasites, now completely lacking PbICP, exhibited an attenuated phenotype but were able to infect mosquitoes and develop to the oocyst stage. However, PbICP-negative sporozoites liberated from oocysts exhibited defective motility and invaded mosquito salivary glands in low numbers. They were also unable to invade hepatocytes, confirming that control of cysteine protease activity is of critical importance for sporozoites. Importantly, transfection of PbICP-knockout parasites with a pbicp-gfp construct fully reversed these defects. Taken together, in P. berghei this inhibitor of the ICP family is essential for sporozoite motility but also appears to play a role during parasite development in hepatocytes and erythrocytes.

  2. A novel cysteine-rich antimicrobial peptide from the mucus of the snail of Achatina fulica.

    Science.gov (United States)

    Zhong, Jian; Wang, Wenhong; Yang, Xiaomei; Yan, Xiuwen; Liu, Rui

    2013-01-01

    Antimicrobial peptides (AMPs) are important components of the innate immunity. Many antimicrobial peptides have been found from marine mollusks. Little information about AMPs of mollusks living on land is available. A novel cysteine-rich antimicrobial peptide (mytimacin-AF) belonging to the peptide family of mytimacins was purified and characterized from the mucus of the snail of Achatina fulica. Its cDNA was also cloned from the cDNA library. Mytimacin-AF is composed of 80 amino acid residues including 10 cysteines. Mytimacin-AF showed potent antimicrobial activity against Gram-negative and Gram-positive bacteria and the fungus Candida albicans. Among tested microorganisms, it exerted strongest antimicrobial activity against Staphylococcus aureus with a minimal peptide concentration (MIC) of 1.9 μg/ml. Mytimacin-AF had little hemolytic activity against human blood red cells. The current work confirmed the presence of mytimacin-like antimicrobial peptide in land-living mollusks. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  3. Conservation Value

    OpenAIRE

    Tisdell, Clement A.

    2010-01-01

    This paper outlines the significance of the concept of conservation value and discusses ways in which it is determined paying attention to views stemming from utilitarian ethics and from deontological ethics. The importance of user costs in relation to economic decisions about the conservation and use of natural resources is emphasised. Particular attention is given to competing views about the importance of conserving natural resources in order to achieve economic sustainability. This then l...

  4. Three-Fingered RAVERs: Rapid Accumulation of Variations in Exposed Residues of Snake Venom Toxins

    Science.gov (United States)

    Sunagar, Kartik; Jackson, Timothy N. W.; Undheim, Eivind A. B.; Ali, Syed. A.; Antunes, Agostinho; Fry, Bryan G.

    2013-01-01

    Three-finger toxins (3FTx) represent one of the most abundantly secreted and potently toxic components of colubrid (Colubridae), elapid (Elapidae) and psammophid (Psammophiinae subfamily of the Lamprophidae) snake venom arsenal. Despite their conserved structural similarity, they perform a diversity of biological functions. Although they are theorised to undergo adaptive evolution, the underlying diversification mechanisms remain elusive. Here, we report the molecular evolution of different 3FTx functional forms and show that positively selected point mutations have driven the rapid evolution and diversification of 3FTx. These diversification events not only correlate with the evolution of advanced venom delivery systems (VDS) in Caenophidia, but in particular the explosive diversification of the clade subsequent to the evolution of a high pressure, hollow-fanged VDS in elapids, highlighting the significant role of these toxins in the evolution of advanced snakes. We show that Type I, II and III α-neurotoxins have evolved with extreme rapidity under the influence of positive selection. We also show that novel Oxyuranus/Pseudonaja Type II forms lacking the apotypic loop-2 stabilising cysteine doublet characteristic of Type II forms are not phylogenetically basal in relation to other Type IIs as previously thought, but are the result of secondary loss of these apotypic cysteines on at least three separate occasions. Not all 3FTxs have evolved rapidly: κ-neurotoxins, which form non-covalently associated heterodimers, have experienced a relatively weaker influence of diversifying selection; while cytotoxic 3FTx, with their functional sites, dispersed over 40% of the molecular surface, have been extremely constrained by negative selection. We show that the a previous theory of 3FTx molecular evolution (termed ASSET) is evolutionarily implausible and cannot account for the considerable variation observed in very short segments of 3FTx. Instead, we propose a theory of

  5. Formation of S-(carboxymethyl)-cysteine in rat liver mitochondrial proteins: effects of caloric and methionine restriction.

    Science.gov (United States)

    Naudí, Alba; Jové, Mariona; Cacabelos, Daniel; Ayala, Victoria; Cabre, Rosanna; Caro, Pilar; Gomez, José; Portero-Otín, Manuel; Barja, Gustavo; Pamplona, Reinald

    2013-02-01

    Maillard reaction contributes to the chemical modification and cross-linking of proteins. This process plays a significant role in the aging process and determination of animal longevity. Oxidative conditions promote the Maillard reaction. Mitochondria are the primary site of oxidants due to the reactive molecular species production. Mitochondrial proteome cysteine residues are targets of oxidative attack due to their specific chemistry and localization. Their chemical, non-enzymatic modification leads to dysfunctional proteins, which entail cellular senescence and organismal aging. Previous studies have consistently shown that caloric and methionine restrictions, nutritional interventions that increase longevity, decrease the rate of mitochondrial oxidant production and the physiological steady-state levels of markers of oxidative damage to macromolecules. In this scenario, we have detected S-(carboxymethyl)-cysteine (CMC) as a new irreversible chemical modification in mitochondrial proteins. CMC content in mitochondrial proteins significantly correlated with that of the lysine-derived analog N (ε)-(carboxymethyl)-lysine. The concentration of CMC is, however, one order of magnitude lower compared with CML likely due in part to the lower content of cysteine with respect to lysine of the mitochondrial proteome. CMC concentrations decreases in liver mitochondrial proteins of rats subjected to 8.5 and 25 % caloric restriction, as well as in 40 and 80 % methionine restriction. This is associated with a concomitant and significant increase in the protein content of sulfhydryl groups. Data presented here evidence that CMC, a marker of Cys-AGE formation, could be candidate as a biomarker of mitochondrial damage during aging.

  6. The Role of Cysteine Residues in Catalysis of Phosphoenolpyruvate Carboxykinase from Mycobacterium tuberculosis

    Czech Academy of Sciences Publication Activity Database

    Machová, Iva; Hubálek, Martin; Lepšík, Martin; Bednárová, Lucie; Pazderková, Markéta; Kopecký, V. Jr.; Snášel, Jan; Dostál, Jiří; Pichová, Iva

    2017-01-01

    Roč. 12, č. 1 (2017), č. článku e0170373. E-ISSN 1932-6203 R&D Projects: GA MŠk LO1302; GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388963 Keywords : structural insights * metabolism * parameters Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 2.806, year: 2016 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0170373

  7. Cysteine residue is not essential for CPM protein thermal-stability assay.

    Science.gov (United States)

    Wang, Zhaoshuai; Ye, Cui; Zhang, Xinyi; Wei, Yinan

    2015-05-01

    A popular thermal-stability assay developed especially for the study of membrane proteins uses a thiol-specific probe, 7-diethylamino-3-(4-maleimidophenyl)-4-methylcoumarin (CPM). The fluorescence emission of CPM surges when it forms a covalent bond with the side chain of a free Cys, which becomes more readily accessible upon protein thermal denaturation. Interestingly, the melting temperatures of membrane proteins determined using the CPM assay in literature are closely clustered in the temperature range 45-55 °C. A thorough understanding of the mechanism behind the observed signal change is critical for the accurate interpretation of the protein unfolding. Here we used two α-helical membrane proteins, AqpZ and AcrB, as model systems to investigate the nature of the fluorescence surge in the CPM assay. We found that the transition temperatures measured using circular-dichroism (CD) spectroscopy and the CPM assay were significantly different. To eliminate potential artifact that might arise from the presence of detergent, we monitored the unfolding of two soluble proteins. We found that, contrary to current understanding, the presence of a sulfhydryl group was not a prerequisite for the CPM thermal-stability assay. The observed fluorescence increase is probably caused by binding of the fluorophore to hydrophobic patches exposed upon protein unfolding.

  8. Cysteine peptidases and their inhibitors in breast and genital cancer.

    Directory of Open Access Journals (Sweden)

    Magdalena Milan

    2010-11-01

    Full Text Available Cysteine proteinases and their inhibitors probably play the main role in carcinogenesis and metastasis. The metastasis process need external proteolytic activities that pass several barriers which are membranous structures of the connective tissue which includes, the basement membrane of blood vessels. Activities of the proteinases are regulated by endogenous inhibitors and activators. The imbalance between cysteine proteinases and cystatins seems to be associated with an increase in metastatic potential in some tumors. It has also been reported that proteinase inhibitors, specific antibodies for these enzymes and inhibition of the urokinase receptor may prevent cancer cell invasion. Some proteinase inhibitor could serve as agents for cancer treatment.

  9. Residual nilpotence and residual solubility of groups

    International Nuclear Information System (INIS)

    Mikhailov, R V

    2005-01-01

    The properties of the residual nilpotence and the residual solubility of groups are studied. The main objects under investigation are the class of residually nilpotent groups such that each central extension of these groups is also residually nilpotent and the class of residually soluble groups such that each Abelian extension of these groups is residually soluble. Various examples of groups not belonging to these classes are constructed by homological methods and methods of the theory of modules over group rings. Several applications of the theory under consideration are presented and problems concerning the residual nilpotence of one-relator groups are considered.

  10. Sequence differences in the diagnostic region of the cysteine protease 8 gene of Tritrichomonas foetus parasites of cats and cattle.

    Science.gov (United States)

    Sun, Zichen; Stack, Colin; Šlapeta, Jan

    2012-05-25

    In order to investigate the genetic variation between Tritrichomonas foetus from bovine and feline origins, cysteine protease 8 (CP8) coding sequence was selected as the polymorphic DNA marker. Direct sequencing of CP8 coding sequence of T. foetus from four feline isolates and two bovine isolates with polymerase chain reaction successfully revealed conserved nucleotide polymorphisms between feline and bovine isolates. These results provide useful information for CP8-based molecular differentiation of T. foetus genotypes. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Structures of Preferred Human IgV Genes-Based Protective Antibodies Identify How Conserved Residues Contact Diverse Antigens and Assign Source of Specificity to CDR3 Loop Variation.

    Science.gov (United States)

    Bryson, Steve; Thomson, Christy A; Risnes, Louise F; Dasgupta, Somnath; Smith, Kenneth; Schrader, John W; Pai, Emil F

    2016-06-01

    The human Ab response to certain pathogens is oligoclonal, with preferred IgV genes being used more frequently than others. A pair of such preferred genes, IGVK3-11 and IGVH3-30, contributes to the generation of protective Abs directed against the 23F serotype of the pneumonococcal capsular polysaccharide of Streptococcus pneumoniae and against the AD-2S1 peptide of the gB membrane protein of human CMV. Structural analyses of Fab fragments of mAbs 023.102 and pn132p2C05 in complex with portions of the 23F polysaccharide revealed five germline-encoded residues in contact with the key component, l-rhamnose. In the case of the AD-2S1 peptide, the KE5 Fab fragment complex identified nine germline-encoded contact residues. Two of these germline-encoded residues, Arg91L and Trp94L, contact both the l-rhamnose and the AD-2S1 peptide. Comparison of the respective paratopes that bind to carbohydrate and protein reveals that stochastic diversity in both CDR3 loops alone almost exclusively accounts for their divergent specificity. Combined evolutionary pressure by human CMV and the 23F serotype of S. pneumoniae acted on the IGVK3-11 and IGVH3-30 genes as demonstrated by the multiple germline-encoded amino acids that contact both l-rhamnose and AD-2S1 peptide. Copyright © 2016 by The American Association of Immunologists, Inc.

  12. Overexpression of an Arabidopsis cysteine-rich receptor-like protein kinase, CRK5, enhances abscisic acid sensitivity and confers drought tolerance.

    Science.gov (United States)

    Lu, Kai; Liang, Shan; Wu, Zhen; Bi, Chao; Yu, Yong-Tao; Wang, Xiao-Fang; Zhang, Da-Peng

    2016-09-01

    Receptor-like kinases (RLKs) have been reported to regulate many developmental and defense process, but only a few members have been functionally characterized. In the present study, our observations suggest that one of the RLKs, a membrane-localized cysteine-rich receptor-like protein kinase, CRK5, is involved in abscisic acid (ABA) signaling in Arabidopsis thaliana Overexpression of CRK5 increases ABA sensitivity in ABA-induced early seedling growth arrest and promotion of stomatal closure and inhibition of stomatal opening. Interestingly, and importantly, overexpression of CRK5 enhances plant drought tolerance without affecting plant growth at the mature stages and plant productivity. Transgenic lines overexpressing a mutated form of CRK5, CRK5 (K372E) with the change of the 372nd conserved amino acid residue from lysine to glutamic acid in its kinase domain, result in wild-type ABA and drought responses, supporting the role of CRK5 in ABA signaling. The loss-of-function mutation of the CRK5 gene does not affect the ABA response, while overexpression of two homologs of CRK5, CRK4 and CRK19, confers ABA responses, suggesting that these CRK members function redundantly. We further showed that WRKY18, WRKY40 and WRKY60 transcription factors repress the expression of CRK5, and that CRK5 likely functions upstream of ABI2 in ABA signaling. These findings help in understanding the complex ABA signaling network. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  13. Bimodal voltage dependence of TRPA1: mutations of a key pore helix residue reveal strong intrinsic voltage-dependent inactivation.

    Science.gov (United States)

    Wan, Xia; Lu, Yungang; Chen, Xueqin; Xiong, Jian; Zhou, Yuanda; Li, Ping; Xia, Bingqing; Li, Min; Zhu, Michael X; Gao, Zhaobing

    2014-07-01

    Transient receptor potential A1 (TRPA1) is implicated in somatosensory processing and pathological pain sensation. Although not strictly voltage-gated, ionic currents of TRPA1 typically rectify outwardly, indicating channel activation at depolarized membrane potentials. However, some reports also showed TRPA1 inactivation at high positive potentials, implicating voltage-dependent inactivation. Here we report a conserved leucine residue, L906, in the putative pore helix, which strongly impacts the voltage dependency of TRPA1. Mutation of the leucine to cysteine (L906C) converted the channel from outward to inward rectification independent of divalent cations and irrespective to stimulation by allyl isothiocyanate. The mutant, but not the wild-type channel, displayed exclusively voltage-dependent inactivation at positive potentials. The L906C mutation also exhibited reduced sensitivity to inhibition by TRPA1 blockers, HC030031 and ruthenium red. Further mutagenesis of the leucine to all natural amino acids individually revealed that most substitutions at L906 (15/19) resulted in inward rectification, with exceptions of three amino acids that dramatically reduced channel activity and one, methionine, which mimicked the wild-type channel. Our data are plausibly explained by a bimodal gating model involving both voltage-dependent activation and inactivation of TRPA1. We propose that the key pore helix residue, L906, plays an essential role in responding to the voltage-dependent gating.

  14. Cysteine-free peptides in scorpion venom: geographical distribution ...

    African Journals Online (AJOL)

    GRACE

    2006-12-29

    Dec 29, 2006 ... In 1993, the first cysteine-free peptide was isolated from scorpion venom. ..... Venom is produced by 2 venom glands in the tail and stored in 2 ... The resistance of a variety of bacterial micro-organisms .... Biopolymers 55: 4-30.

  15. A Serendipitous Formation of a Cysteine-bridged Disaccharide

    African Journals Online (AJOL)

    NICO

    O-acetyl-b-D-glucopyranosylisothiouronium salt and the iodide or tosyl derivatives of L-serine,3 the desulfurization of disulfide- linked glycosyl cysteine derivatives,4 Lewis acid-catalyzed glycosylation,5,6 and solid phase glycosylation.7. Glycosylation of amino acids has previously relied on the use of amino acids protected ...

  16. Isolation of recombinant cysteine dioxygenase protein from Trichophyton mentagrophytes

    Czech Academy of Sciences Publication Activity Database

    Kašperová, A.; Kunert, J.; Horynová, M.; Weigl, E.; Sebela, M.; Lenobel, René; Raška, M.

    2011-01-01

    Roč. 54, č. 5 (2011), E456-E462 ISSN 0933-7407 R&D Projects: GA ČR GA301/08/1649 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cysteine dioxygenase * dermatophytes * recombinant protein * keratinolytic fungi * cDNA Subject RIV: CE - Biochemistry Impact factor: 2.247, year: 2011

  17. Cysteine Protease Inhibitors as Chemotherapy: Lessons from a Parasite Target

    Science.gov (United States)

    Selzer, Paul M.; Pingel, Sabine; Hsieh, Ivy; Ugele, Bernhard; Chan, Victor J.; Engel, Juan C.; Bogyo, Matthew; Russell, David G.; Sakanari, Judy A.; McKerrow, James H.

    1999-09-01

    Papain family cysteine proteases are key factors in the pathogenesis of cancer invasion, arthritis, osteoporosis, and microbial infections. Targeting this enzyme family is therefore one strategy in the development of new chemotherapy for a number of diseases. Little is known, however, about the efficacy, selectivity, and safety of cysteine protease inhibitors in cell culture or in vivo. We now report that specific cysteine protease inhibitors kill Leishmania parasites in vitro, at concentrations that do not overtly affect mammalian host cells. Inhibition of Leishmania cysteine protease activity was accompanied by defects in the parasite's lysosome/endosome compartment resembling those seen in lysosomal storage diseases. Colocalization of anti-protease antibodies with biotinylated surface proteins and accumulation of undigested debris and protease in the flagellar pocket of treated parasites were consistent with a pathway of protease trafficking from flagellar pocket to the lysosome/endosome compartment. The inhibitors were sufficiently absorbed and stable in vivo to ameliorate the pathology associated with a mouse model of Leishmania infection.

  18. Chemical detection of cysteine-rich circular petides in selected ...

    African Journals Online (AJOL)

    Cysteine-rich circular peptides (CRCs) comprise a large family of gene encoded and low molecular weight polypeptides that has recently engaged the attention of scientists. This class of peptides exhibit a continuous circular configuration and a cystine knot backbone, which defines their resilient nature-directed structural ...

  19. Targeting cysteine proteases in trypanosomatid disease drug discovery.

    Science.gov (United States)

    Ferreira, Leonardo G; Andricopulo, Adriano D

    2017-12-01

    Chagas disease and human African trypanosomiasis are endemic conditions in Latin America and Africa, respectively, for which no effective and safe therapy is available. Efforts in drug discovery have focused on several enzymes from these protozoans, among which cysteine proteases have been validated as molecular targets for pharmacological intervention. These enzymes are expressed during the entire life cycle of trypanosomatid parasites and are essential to many biological processes, including infectivity to the human host. As a result of advances in the knowledge of the structural aspects of cysteine proteases and their role in disease physiopathology, inhibition of these enzymes by small molecules has been demonstrated to be a worthwhile approach to trypanosomatid drug research. This review provides an update on drug discovery strategies targeting the cysteine peptidases cruzain from Trypanosoma cruzi and rhodesain and cathepsin B from Trypanosoma brucei. Given that current chemotherapy for Chagas disease and human African trypanosomiasis has several drawbacks, cysteine proteases will continue to be actively pursued as valuable molecular targets in trypanosomatid disease drug discovery efforts. Copyright © 2017. Published by Elsevier Inc.

  20. Chemoselective PEGylation of Cysteine Analogs of Human Basic ...

    African Journals Online (AJOL)

    Purpose: To improve the stability and bioactivity of human basic fibroblast growth factor (hbFGF) by site-specific pegylation. Methods: Four new mutants of hbFGF were designed with substituted Asp68, Lys77, Glu78 and Arg81 with cysteine with the aid of bioinformatics technique, and then cloned into pET21a plasmid, ...

  1. Cysteine and hydrogen sulfide in the regulation of metabolism:Insights from genetics and pharmacology

    OpenAIRE

    Carter, Roderick N; Morton, Nicholas M

    2016-01-01

    Abstract Obesity and diabetes represent a significant and escalating worldwide health burden. These conditions are characterized by abnormal nutrient homeostasis. One such perturbation is altered metabolism of the sulphur?containing amino acid cysteine. Obesity is associated with elevated plasma cysteine, whereas diabetes is associated with reduced cysteine levels. One mechanism by which cysteine may act is through its enzymatic breakdown to produce hydrogen sulphide (H2S), a gasotransmitter ...

  2. An evaluation of preservation of residual hearing using the suprameatal approach for cochlear implantation: can this implantation technique be used for preservation of residual hearing?

    NARCIS (Netherlands)

    Postelmans, Job T. F.; van Spronsen, Erik; Grolman, Wilko; Stokroos, Robert J.; Tange, Rinze A.; Maré, Marcel J.; Dreschler, Wouter A.

    2011-01-01

    The preservation of residual hearing has become a high priority in cochlear implant surgery. This study was designed to substantiate whether conservation of residual hearing can be preserved after cochlear implantation using the suprameatal approach. Retrospective chart review. Retrospective chart

  3. Mutagenicity and cytotoxicity of two regioisomeric mercapturic acids and cysteine S-conjugates of trichloroethylene.

    NARCIS (Netherlands)

    Commandeur, J.N.M.; Boogaard, P.J.; Mulder, G.J.; Vermeulen, N.P.E.

    1991-01-01

    The mutagenicity, cytotoxicity and metabolism of two regioisomic l-cysteine- and N-acetyl-l-cysteine-S-conjugates of trichloroethylene were studied. The 1,2-dichlorovinyl(1,2-DCV) isomers of both the cysteine conjugate and the mercapturate were much stronger mutagens in the Ames test with Salmonella

  4. Effects of cysteine on growth, protease production, and catalase activity of Pseudomonas fluorescens.

    OpenAIRE

    Himelbloom, B H; Hassan, H M

    1986-01-01

    Cysteine inhibits growth of and protease production by Pseudomonas fluorescens NC3. Catalase activity in P. fluorescens NC3 was increased by cysteine. The addition of exogenous hydrogen peroxide did not increase catalase activity, thus suggesting a role for the endogenous generation of hydrogen peroxide via the autoxidation of cysteine.

  5. Thermal decomposition of the amino acids glycine, cysteine, aspartic acid, asparagine, glutamic acid, glutamine, arginine and histidine.

    Science.gov (United States)

    Weiss, Ingrid M; Muth, Christina; Drumm, Robert; Kirchner, Helmut O K

    2018-01-01

    The pathways of thermal instability of amino acids have been unknown. New mass spectrometric data allow unequivocal quantitative identification of the decomposition products. Calorimetry, thermogravimetry and mass spectrometry were used to follow the thermal decomposition of the eight amino acids G, C, D, N, E, Q, R and H between 185 °C and 280 °C. Endothermic heats of decomposition between 72 and 151 kJ/mol are needed to form 12 to 70% volatile products. This process is neither melting nor sublimation. With exception of cysteine they emit mainly H 2 O, some NH 3 and no CO 2 . Cysteine produces CO 2 and little else. The reactions are described by polynomials, AA→ a NH 3 + b H 2 O+ c CO 2 + d H 2 S+ e residue, with integer or half integer coefficients. The solid monomolecular residues are rich in peptide bonds. Eight of the 20 standard amino acids decompose at well-defined, characteristic temperatures, in contrast to commonly accepted knowledge. Products of decomposition are simple. The novel quantitative results emphasize the impact of water and cyclic condensates with peptide bonds and put constraints on hypotheses of the origin, state and stability of amino acids in the range between 200 °C and 300 °C.

  6. Importance of uncharged polar residues and proline in the proximal two-thirds (Pro107–Ser128 of the highly conserved region of mouse ileal Na+-dependent bile acid transporter, Slc10a2, in transport activity and cellular expression

    Directory of Open Access Journals (Sweden)

    Saeki Tohru

    2013-02-01

    Full Text Available Abstract Background SLC10A2-mediated reabsorption of bile acids at the distal end of the ileum is the first step in enterohepatic circulation. Because bile acids act not only as detergents but also as signaling molecules in lipid metabolism and energy production, SLC10A2 is important as the key transporter for understanding the in vivo kinetics of bile acids. SLC10A family members and the homologous genes of various species share a highly conserved region corresponding to Gly104–Pro142 of SLC10A2. The functional importance of this region has not been fully elucidated. Results To elucidate the functional importance of this region, we previously performed mutational analysis of the uncharged polar residues and proline in the distal one-third (Thr130–Pro142 of the highly conserved region in mouse Slc10a2. In this study, proline and uncharged polar residues in the remaining two-thirds of this region in mouse Slc10a2 were subjected to mutational analysis, and taurocholic acid uptake and cell surface localization were examined. Cell surface localization of Slc10a2 is necessary for bile acid absorption. Mutants in which Asp or Leu were substituted for Pro107 (P107N or P107L were abundantly expressed, but their cell surface localization was impaired. The S126A mutant was completely impaired in cellular expression. The T110A and S128A mutants exhibited remarkably enhanced membrane expression. The S112A mutant was properly expressed at the cell surface but transport activity was completely lost. Replacement of Tyr117 with various amino acids resulted in reduced transport activity. The degree of reduction roughly depended on the van der Waals volume of the side chains. Conclusions The functional importance of proline and uncharged polar residues in the highly conserved region of mouse Slc10a2 was determined. This information will contribute to the design of bile acid-conjugated prodrugs for efficient drug delivery or SLC10A2 inhibitors for

  7. Protein structure based prediction of catalytic residues.

    Science.gov (United States)

    Fajardo, J Eduardo; Fiser, Andras

    2013-02-22

    Worldwide structural genomics projects continue to release new protein structures at an unprecedented pace, so far nearly 6000, but only about 60% of these proteins have any sort of functional annotation. We explored a range of features that can be used for the prediction of functional residues given a known three-dimensional structure. These features include various centrality measures of nodes in graphs of interacting residues: closeness, betweenness and page-rank centrality. We also analyzed the distance of functional amino acids to the general center of mass (GCM) of the structure, relative solvent accessibility (RSA), and the use of relative entropy as a measure of sequence conservation. From the selected features, neural networks were trained to identify catalytic residues. We found that using distance to the GCM together with amino acid type provide a good discriminant function, when combined independently with sequence conservation. Using an independent test set of 29 annotated protein structures, the method returned 411 of the initial 9262 residues as the most likely to be involved in function. The output 411 residues contain 70 of the annotated 111 catalytic residues. This represents an approximately 14-fold enrichment of catalytic residues on the entire input set (corresponding to a sensitivity of 63% and a precision of 17%), a performance competitive with that of other state-of-the-art methods. We found that several of the graph based measures utilize the same underlying feature of protein structures, which can be simply and more effectively captured with the distance to GCM definition. This also has the added the advantage of simplicity and easy implementation. Meanwhile sequence conservation remains by far the most influential feature in identifying functional residues. We also found that due the rapid changes in size and composition of sequence databases, conservation calculations must be recalibrated for specific reference databases.

  8. Conservation endocrinology

    Science.gov (United States)

    McCormick, Stephen; Romero, L. Michael

    2017-01-01

    Endocrinologists can make significant contributions to conservation biology by helping to understand the mechanisms by which organisms cope with changing environments. Field endocrine techniques have advanced rapidly in recent years and can provide substantial information on the growth, stress, and reproductive status of individual animals, thereby providing insight into current and future responses of populations to changes in the environment. Environmental stressors and reproductive status can be detected nonlethally by measuring a number of endocrine-related endpoints, including steroids in plasma, living and nonliving tissue, urine, and feces. Information on the environmental or endocrine requirements of individual species for normal growth, development, and reproduction will provide critical information for species and ecosystem conservation. For many taxa, basic information on endocrinology is lacking, and advances in conservation endocrinology will require approaches that are both “basic” and “applied” and include integration of laboratory and field approaches.

  9. Mutant form C115H of Clostridium sporogenes methionine γ-lyase efficiently cleaves S-Alk(en)yl-l-cysteine sulfoxides to antibacterial thiosulfinates.

    Science.gov (United States)

    Kulikova, Vitalia V; Anufrieva, Natalya V; Revtovich, Svetlana V; Chernov, Alexander S; Telegin, Georgii B; Morozova, Elena A; Demidkina, Tatyana V

    2016-10-01

    Pyridoxal 5'-phosphate-dependent methionine γ-lyase (MGL) catalyzes the β-elimination reaction of S-alk(en)yl-l-cysteine sulfoxides to thiosulfinates, which possess antimicrobial activity. Partial inactivation of the enzyme in the course of the reaction occurs due to oxidation of active site cysteine 115 conserved in bacterial MGLs. In this work, the C115H mutant form of Clostridium sporogenes MGL was prepared and the steady-state kinetic parameters of the enzyme were determined. The substitution results in an increase in the catalytic efficiency of the mutant form towards S-substituted l-cysteine sulfoxides compared to the wild type enzyme. We used a sulfoxide/enzyme system to generate antibacterial activity in situ. Two-component systems composed of the mutant enzyme and three S-substituted l-cysteine sulfoxides were demonstrated to be effective against Gram-positive and Gram-negative bacteria and three clinical isolates from mice. © 2016 IUBMB Life, 68(10):830-835, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

  10. The conserved scavenger receptor cysteine-rich superfamily in therapy and diagnosis

    DEFF Research Database (Denmark)

    Martínez, Vanesa Gabriela; Moestrup, Søren Kragh; Holmskov, Uffe

    2011-01-01

    members of the SRCR-SF, but also of the sequence versatility of the SRCR domains. Indeed, involvement of SRCR-SF members in quite different functions, such as pathogen recognition, modulation of the immune response, epithelial homeostasis, stem cell biology, and tumor development, have all been described...... expansion, now up to more than 30 members. The study of these members is attracting growing interest, which parallels that in innate immunity. No unifying function has been described to date for the SRCR domains, this being the result of the limited knowledge still available on the physiology of most...

  11. Evolutionary conserved cysteines function as cis-acting regulators of arabidopsis PIN-FORMED 2 distribution

    Czech Academy of Sciences Publication Activity Database

    Retzer, Katarzyna; Lacek, Jozef; Skokan, Roman; Del Genio, C. H.; Vosolsobě, S.; Laňková, Martina; Malínská, Kateřina; Konstantinova, N.; Zažímalová, Eva; Napier, R. M.; Petrášek, Jan; Luschnig, C.

    2017-01-01

    Roč. 18, č. 11 (2017), č. článku 2274. E-ISSN 1422-0067 R&D Projects: GA ČR(CZ) GAP305/11/0797 Grant - others:OPPK(XE) CZ.2.16/3.1.00/21519 Institutional support: RVO:61389030 Keywords : Arabidopsis * Auxin * Intracellular distribution * PIN proteins * Plasma membrane protein sorting * Protein mobility * Protein modeling * Root phenotype * srrf Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Plant sciences, botany Impact factor: 3.226, year: 2016

  12. Cathepsin F cysteine protease of the human liver fluke, Opisthorchis viverrini.

    Directory of Open Access Journals (Sweden)

    Porntip Pinlaor

    Full Text Available The liver fluke Opisthorchis viverrini is classified as a class I carcinogen due to the association between cholangiocarcinoma and chronic O. viverrini infection. During its feeding activity within the bile duct, the parasite secretes several cathepsin F cysteine proteases that may induce or contribute to the pathologies associated with hepatobiliary abnormalities.Here, we describe the cDNA, gene organization, phylogenetic relationships, immunolocalization, and functional characterization of the cathepsin F cysteine protease gene, here termed Ov-cf-1, from O. viverrini. The full length mRNA of 1020 nucleotides (nt encoded a 326 amino acid zymogen consisting of a predicted signal peptide (18 amino acids, aa, prosegment (95 aa, and mature protease (213 aa. BLAST analysis using the Ov-CF-1 protein as the query revealed that the protease shared identity with cathepsin F-like cysteine proteases of other trematodes, including Clonorchis sinensis (81%, Paragonimus westermani (58%, Schistosoma mansoni and S. japonicum (52%, and with vertebrate cathepsin F (51%. Transcripts encoding the protease were detected in all developmental stages that parasitize the mammalian host. The Ov-cf-1 gene, of approximately 3 kb in length, included seven exons interrupted by six introns; the exons ranged from 69 to 267 bp in length, the introns from 43 to 1,060 bp. The six intron/exon boundaries of Ov-cf-1 were conserved with intron/exon boundaries in the human cathepsin F gene, although the gene structure of human cathepsin F is more complex. Unlike Ov-CF-1, human cathepsin F zymogen includes a cystatin domain in the prosegment region. Phylogenetic analysis revealed that the fluke, human, and other cathepsin Fs branched together in a clade discrete from the cathepsin L cysteine proteases. A recombinant Ov-CF-1 zymogen that displayed low-level activity was expressed in the yeast Pichia pastoris. Although the recombinant protease did not autocatalytically process and

  13. Barley (Hordeum vulgare L.) cysteine proteases: heterologous expression, purification and characterization

    DEFF Research Database (Denmark)

    Rosenkilde, Anne Lind; Dionisio, Giuseppe; Holm, Preben Bach

    2011-01-01

    During germination of barley seeds, mobilization of protein is essential and cysteine proteases accounts for more than 90 % of the total proteolytic activity in the degradation of barley seed storage proteins. Cysteine proteases exist as pro-enzyme and is activated through reduction of the active...... site cysteines and by removal of the pro-domain. The complement of cysteine proteases is comprehensive and for detailed studies of the individual components of this complement, a fast and efficient eukaryotic expression platform is highly desirable. A cDNA clone of the barley key cysteine endoprotease...

  14. [Conservation Units.

    Science.gov (United States)

    Texas Education Agency, Austin.

    Each of the six instructional units deals with one aspect of conservation: forests, water, rangeland, minerals (petroleum), and soil. The area of the elementary school curriculum with which each correlates is indicated. Lists of general and specific objectives are followed by suggested teaching procedures, including ideas for introducing the…

  15. Creative conservation

    NARCIS (Netherlands)

    Bentham, Roelof J.

    1968-01-01

    The increasing exploitation of our natural resources, the unlimited occupation of ever more new areas, and the intensification of land-use, make it necessary for us to expand the concept of conservation. But we also need to reconsider that concept itself. For the changing conditions in the

  16. Reshaping conservation

    DEFF Research Database (Denmark)

    Funder, Mikkel; Danielsen, Finn; Ngaga, Yonika

    2013-01-01

    members strengthen the monitoring practices to their advantage, and to some extent move them beyond the reach of government agencies and conservation and development practitioners. This has led to outcomes that are of greater social and strategic value to communities than the original 'planned' benefits...

  17. Cysteine protease inhibition by nitrile-based inhibitors: a computational study

    Science.gov (United States)

    Quesne, Matthew G.; Ward, Richard A.; de Visser, Sam P.

    2013-01-01

    Cysteine protease enzymes are important for human physiology and catalyze key protein degradation pathways. These enzymes react via a nucleophilic reaction mechanism that involves a cysteine residue and the proton of a proximal histidine. Particularly efficient inhibitors of these enzymes are nitrile-based, however, the details of the catalytic reaction mechanism currently are poorly understood. To gain further insight into the inhibition of these molecules, we have performed a combined density functional theory and quantum mechanics/molecular mechanics study on the reaction of a nitrile-based inhibitor with the enzyme active site amino acids. We show here that small perturbations to the inhibitor structure can have dramatic effects on the catalysis and inhibition processes. Thus, we investigated a range of inhibitor templates and show that specific structural changes reduce the inhibitory efficiency by several orders of magnitude. Moreover, as the reaction takes place on a polar surface, we find strong differences between the DFT and QM/MM calculated energetics. In particular, the DFT model led to dramatic distortions from the starting structure and the convergence to a structure that would not fit the enzyme active site. In the subsequent QM/MM study we investigated the use of mechanical vs. electronic embedding on the kinetics, thermodynamics and geometries along the reaction mechanism. We find minor effects on the kinetics of the reaction but large geometric and thermodynamics differences as a result of inclusion of electronic embedding corrections. The work here highlights the importance of model choice in the investigation of this biochemical reaction mechanism. PMID:24790966

  18. Dimerization of the Glucan Phosphatase Laforin Requires the Participation of Cysteine 329

    Science.gov (United States)

    Sánchez-Martín, Pablo; Raththagala, Madushi; Bridges, Travis M.; Husodo, Satrio; Gentry, Matthew S.; Sanz, Pascual; Romá-Mateo, Carlos

    2013-01-01

    Laforin, encoded by a gene that is mutated in Lafora Disease (LD, OMIM 254780), is a modular protein composed of a carbohydrate-binding module and a dual-specificity phosphatase domain. Laforin is the founding member of the glucan-phosphatase family and regulates the levels of phosphate present in glycogen. Multiple reports have described the capability of laforin to form dimers, although the function of these dimers and their relationship with LD remains unclear. Recent evidence suggests that laforin dimerization depends on redox conditions, suggesting that disulfide bonds are involved in laforin dimerization. Using site-directed mutagenesis we constructed laforin mutants in which individual cysteine residues were replaced by serine and then tested the ability of each protein to dimerize using recombinant protein as well as a mammalian cell culture assay. Laforin-Cys329Ser was the only Cys/Ser mutant unable to form dimers in both assays. We also generated a laforin truncation lacking the last three amino acids, laforin-Cys329X, and this truncation also failed to dimerize. Interestingly, laforin-Cys329Ser and laforin-Cys329X were able to bind glucans, and maintained wild type phosphatase activity against both exogenous and biologically relevant substrates. Furthermore, laforin-Cys329Ser was fully capable of participating in the ubiquitination process driven by a laforin-malin complex. These results suggest that dimerization is not required for laforin phosphatase activity, glucan binding, or for the formation of a functional laforin-malin complex. Cumulatively, these results suggest that cysteine 329 is specifically involved in the dimerization process of laforin. Therefore, the C329S mutant constitutes a valuable tool to analyze the physiological implications of laforin’s oligomerization. PMID:23922729

  19. Fluoresence quenching of riboflavin in aqueous solution by methionin and cystein

    International Nuclear Information System (INIS)

    Droessler, P.; Holzer, W.; Penzkofer, A.; Hegemann, P.

    2003-01-01

    The fluorescence quantum distributions, fluorescence quantum yields, and fluorescence lifetimes of riboflavin in methanol, DMSO, water, and aqueous solutions of the sulphur atom containing amino acids methionin and cystein have been determined. In methanol, DMSO, and water (pH=4-8) only dynamic fluorescence reduction due to intersystem crossing and internal conversion is observed. In aqueous methionin solutions of pH=5.25-9 a pH independent static and dynamic fluorescence quenching occurs probably due to riboflavin anion-methionin cation pair formation. In aqueous cystein solutions (pH range from 4.15 to 9) the fluorescence quenching increases with rising pH due to cystein thiolate formation. The cystein thiol form present at low pH does not react with neutral riboflavin. Cystein thiolate present at high pH seems to react with neutral riboflavin causing riboflavin deprotonation (anion formation) by cystein thiolate reduction to the cystein thiol form

  20. Functional evidence for the critical amino-terminal conserved domain and key amino acids of Arabidopsis 4-HYDROXY-3-METHYLBUT-2-ENYL DIPHOSPHATE REDUCTASE.

    Science.gov (United States)

    Hsieh, Wei-Yu; Sung, Tzu-Ying; Wang, Hsin-Tzu; Hsieh, Ming-Hsiun

    2014-09-01

    The plant 4-HYDROXY-3-METHYLBUT-2-ENYL DIPHOSPHATE REDUCTASE (HDR) catalyzes the last step of the methylerythritol phosphate pathway to synthesize isopentenyl diphosphate and its allyl isomer dimethylallyl diphosphate, which are common precursors for the synthesis of plastid isoprenoids. The Arabidopsis (Arabidopsis thaliana) genomic HDR transgene-induced gene-silencing lines are albino, variegated, or pale green, confirming that HDR is essential for plants. We used Escherichia coli isoprenoid synthesis H (Protein Data Bank code 3F7T) as a template for homology modeling to identify key amino acids of Arabidopsis HDR. The predicted model reveals that cysteine (Cys)-122, Cys-213, and Cys-350 are involved in iron-sulfur cluster formation and that histidine (His)-152, His-241, glutamate (Glu)-242, Glu-243, threonine (Thr)-244, Thr-312, serine-379, and asparagine-381 are related to substrate binding or catalysis. Glu-242 and Thr-244 are conserved only in cyanobacteria, green algae, and land plants, whereas the other key amino acids are absolutely conserved from bacteria to plants. We used site-directed mutagenesis and complementation assay to confirm that these amino acids, except His-152 and His-241, were critical for Arabidopsis HDR function. Furthermore, the Arabidopsis HDR contains an extra amino-terminal domain following the transit peptide that is highly conserved from cyanobacteria, and green algae to land plants but not existing in the other bacteria. We demonstrated that the amino-terminal conserved domain was essential for Arabidopsis and cyanobacterial HDR function. Further analysis of conserved amino acids in the amino-terminal conserved domain revealed that the tyrosine-72 residue was critical for Arabidopsis HDR. These results suggest that the structure and reaction mechanism of HDR evolution have become specific for oxygen-evolving photosynthesis organisms and that HDR probably evolved independently in cyanobacteria versus other prokaryotes. © 2014

  1. Subcellular distribution of glutathione and cysteine in cyanobacteria

    OpenAIRE

    Zechmann, Bernd; Tomašić, Ana; Horvat, Lucija; Fulgosi, Hrvoje

    2010-01-01

    Glutathione plays numerous important functions in eukaryotic and prokaryotic cells. Whereas it can be found in virtually all eukaryotic cells, its production in prokaryotes is restricted to cyanobacteria and proteobacteria and a few strains of gram-positive bacteria. In bacteria, it is involved in the protection against reactive oxygen species (ROS), osmotic shock, acidic conditions, toxic chemicals, and heavy metals. Glutathione synthesis in bacteria takes place in two steps out of cysteine,...

  2. Effect of cysteine supplementation on in vitro maturation of bovine ...

    African Journals Online (AJOL)

    B Rahim, S Jalal, N Yosef ... Cumulus-oocyte complexes (COCs) from abattoir ovaries were matured in vitro in Hepes-TCM 199 supplemented with 0.2 mM sodium pyruvate, 1 μg/ml 17-β-estradiol, 10% fetal calf serum (FCS), 0.5 μg/ml bFSH and 0 (control) and 100 or 500 μM/ml of cysteine for 24 h. When COCs matured in ...

  3. Acid-Mediated Tumor Proteolysis: Contribution of Cysteine Cathepsins

    Directory of Open Access Journals (Sweden)

    Jennifer M Rothberg

    2013-10-01

    Full Text Available One of the noncellular microenvironmental factors that contribute to malignancy of solid tumors is acidic peritumoral pH. We have previously demonstrated that extracellular acidosis leads to localization of the cysteine pro-tease cathepsin B on the tumor cell membrane and its secretion. The objective of the present study was to determine if an acidic extracellular pH such as that observed in vivo (i.e., pHe 6.8 affects the activity of proteases, e.g., cathepsin B, that contribute to degradation of collagen IV by tumor cells when grown in biologically relevant three-dimensional (3D cultures. For these studies, we used 1 3D reconstituted basement membrane overlay cultures of human carcinomas, 2 live cell imaging assays to assess proteolysis, and 3 in vivo imaging of active tumor proteases. At pHe 6.8, there were increases in pericellular active cysteine cathepsins and in degradation of dye-quenched collagen IV, which was partially blocked by a cathepsin B inhibitor. Imaging probes for active cysteine cathepsins localized to tumors in vivo. The amount of bound probe decreased in tumors in bicarbonate-treated mice, a treatment previously shown to increase peritumoral pHe and reduce local invasion of the tumors. Our results are consistent with the acid-mediated invasion hypothesis and with a role for cathepsin B in promoting degradation of a basement membrane protein substrate, i.e., type IV collagen, in an acidic peritumoral environment.

  4. The effect of cysteine on electrodeposition of gold nanoparticle

    International Nuclear Information System (INIS)

    Dolati, A.; Imanieh, I.; Salehi, F.; Farahani, M.

    2011-01-01

    Highlights: → Cysteine was found as an appropriate additive for electrodeposition of gold nanoparticles. → The deposition mechanism of gold nanoparticle was determined as instantaneous nucleation. → Oxygen reduction on the gold nanoparticle surface was eight times greater than that on the conventional gold deposits. - Abstract: The most applications of gold nanoparticles are in the photo-electronical accessories and bio-chemical sensors. Chloride solution with cysteine additive was used as electrolyte in gold nanoparticles electrodeposition. The nucleation and growing mechanism were studied by electrochemical techniques such as cyclic voltammetry and chronoamperometry, in order to obtain a suitable nano structure. The deposition mechanism was determined as instantaneous nucleation and the dimension of particles was controlled in nanometric particle size range. Atomic Force Microscope was used to evaluate the effect of cysteine on the morphology and topography of gold nanoparticles. Finally the catalytic property of gold nanoparticle electrodeposited was studied in KOH solution, where oxygen reduction on the gold nanoparticle surface was eight times greater than that on the conventional gold deposits.

  5. Making conservation work for everyone

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, J. [Veridian Corp., Ajax, ON (Canada)

    2004-07-01

    This presentation discussed the economic value of conservation, the optimal deployment of energy conservation. A sample load profile was presented to demonstrate how much electricity the average residential customer uses on a summer day. The average customer does not have the tools to understand the financial consequences of conservation for different types of equipment at different times of the day. Smart metering technology could help in this regard. Accurate unsubsidized prices are also considered to be the best incentive to conserve because customers will reduce electricity use when the prices are high. It was also suggested that standards for new appliances should be increased effectively to their economic value. The enablers to energy conservation include solid consumer education programs, real time metering in places where it is cost effective, real time pricing in places where it is practical, and power rates that reflect real costs. Barriers to energy conservation include the residual economic advantage that may be insufficient to justify investment; support from local distribution companies and transmission companies if the lost revenue adjustment mechanism (LRAM) is not sufficient to recover lost revenue and if LDCs are not sufficiently involved in the design of the electricity conservation program. 7 figs.

  6. Conservation of Charge and Conservation of Current

    OpenAIRE

    Eisenberg, Bob

    2016-01-01

    Conservation of current and conservation of charge are nearly the same thing: when enough is known about charge movement, conservation of current can be derived from conservation of charge, in ideal dielectrics, for example. Conservation of current is enforced implicitly in ideal dielectrics by theories that conserve charge. But charge movement in real materials like semiconductors or ionic solutions is never ideal. We present an apparently universal derivation of conservation of current and ...

  7. Analysis of S-nitrosothiols via Copper Cysteine (2C) and Copper Cysteine - Carbon Monoxide (3C) Methods

    Science.gov (United States)

    Rogers, Stephen C.; Gibbons, Lindsey B.; Griffin, Sherraine; Doctor, Allan

    2012-01-01

    This chapter summarizes the principles of RSNO measurement in the gas phase, utilizing ozone-based chemiluminescence and the copper cysteine (2C) ± carbon monoxide (3C) reagent. Although an indirect method for quantifying RSNOs, this assay represents one of the most robust methodologies available. It exploits the NO• detection sensitivity of ozone based chemiluminscence, which is within the range required to detect physiological concentrations of RSNO metabolites. Additionally, the specificity of the copper cysteine (2C and 3C) reagent for RSNOs negates the need for sample pretreatment, thereby minimizing the likelihood of sample contamination (false positive results), NO species inter-conversion, or the loss of certain highly labile RSNO species. Herein, we outline the principles of this methodology, summarizing key issues, potential pitfalls and corresponding solutions. PMID:23116707

  8. Identification of essential amino acid residues in the nisin dehydratase NisB

    Directory of Open Access Journals (Sweden)

    Rustem eKhusainov

    2015-02-01

    Full Text Available Nisin is a posttranslationally-modified antimicrobial peptide that has the ability to induce its own biosynthesis. Serines and threonines in the modifiable core peptide part of precursor nisin are dehydrated to dehydroalanines and dehydrobutyrines by the dehydratase NisB, and subsequently cysteines are coupled to the dehydroamino acids by the cyclase NisC. In this study, we applied extensive site-directed mutagenesis, together with direct binding studies, to investigate the molecular mechanism of the dehydratase NisB. We use a natural nisin-producing strain as a host to probe mutant-NisB functionality. Importantly, we are able to differentiate between intracellular and secreted fully dehydrated precursor nisin, enabling investigation of the NisB properties needed for the release of dehydrated precursor nisin to its devoted secretion system NisT. We report that single amino acid substitutions of conserved residues, i.e. R83A, R83M and R87A result in incomplete dehydration of precursor nisin and prevention of secretion. Single point NisB mutants Y80F and H961A, result in a complete lack of dehydration of precursor nisin, but do not abrogate precursor nisin binding. The data indicate that residues Y80 and H961 are directly involved in catalysis, fitting well with their position in the recently published 3D-structure of NisB. We confirm, by in vivo studies, results that were previously obtained from in vitro experiments and NisB structure elucidation and show that previous findings translate well to effects seen in the original production host.

  9. The IRC7 gene encodes cysteine desulphydrase activity and confers on yeast the ability to grow on cysteine as a nitrogen source.

    Science.gov (United States)

    Santiago, Margarita; Gardner, Richard C

    2015-07-01

    Although cysteine desulphydrase activity has been purified and characterized from Saccharomyces cerevisiae, the gene encoding this activity in vivo has never been defined. We show that the full-length IRC7 gene, encoded by the YFR055W open reading frame, encodes a protein with cysteine desulphydrase activity. Irc7p purified to homogeneity is able to utilize l-cysteine as a substrate, producing pyruvate and hydrogen sulphide as products of the reaction. Purified Irc7p also utilized l-cystine and some other cysteine conjugates, but not l-cystathionine or l-methionine, as substrates. We further show that, in vivo, the IRC7 gene is both necessary and sufficient for yeast to grow on l-cysteine as a nitrogen source, and that overexpression of the gene results in increased H2 S production. Strains overexpressing IRC7 are also hypersensitive to a toxic analogue, S-ethyl-l-cysteine. While IRC7 has been identified as playing a critical role in converting cysteine conjugates to volatile thiols that are important in wine aroma, its biological role in yeast cells is likely to involve regulation of cysteine and redox homeostasis. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Structure and mechanism leading to formation of the cysteine sulfinate product complex of a biomimetic cysteine dioxygenase model.

    Science.gov (United States)

    Sallmann, Madleen; Kumar, Suresh; Chernev, Petko; Nehrkorn, Joscha; Schnegg, Alexander; Kumar, Devesh; Dau, Holger; Limberg, Christian; de Visser, Sam P

    2015-05-11

    Cysteine dioxygenase is a unique nonheme iron enzyme that is involved in the metabolism of cysteine in the body. It contains an iron active site with an unusual 3-His ligation to the protein, which contrasts with the structural features of common nonheme iron dioxygenases. Recently, some of us reported a truly biomimetic model for this enzyme, namely a trispyrazolylborato iron(II) cysteinato complex, which not only has a structure very similar to the enzyme-substrate complex but also represents a functional model: Treatment of the model with dioxygen leads to cysteine dioxygenation, as shown by isolating the cysteine part of the product in the course of the work-up. However, little is known on the conversion mechanism and, so far, not even the structure of the actual product complex had been characterised, which is also unknown in case of the enzyme. In a multidisciplinary approach including density functional theory calculations and X-ray absorption spectroscopy, we have now determined the structure of the actual sulfinato complex for the first time. The Cys-SO2 (-) functional group was found to be bound in an η(2) -O,O-coordination mode, which, based on the excellent resemblance between model and enzyme, also provides the first support for a corresponding binding mode within the enzymatic product complex. Indeed, this is again confirmed by theory, which had predicted a η(2) -O,O-binding mode for synthetic as well as the natural enzyme. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Identification of novel malarial cysteine protease inhibitors using structure-based virtual screening of a focused cysteine protease inhibitor library.

    Science.gov (United States)

    Shah, Falgun; Mukherjee, Prasenjit; Gut, Jiri; Legac, Jennifer; Rosenthal, Philip J; Tekwani, Babu L; Avery, Mitchell A

    2011-04-25

    Malaria, in particular that caused by Plasmodium falciparum , is prevalent across the tropics, and its medicinal control is limited by widespread drug resistance. Cysteine proteases of P. falciparum , falcipain-2 (FP-2) and falcipain-3 (FP-3), are major hemoglobinases, validated as potential antimalarial drug targets. Structure-based virtual screening of a focused cysteine protease inhibitor library built with soft rather than hard electrophiles was performed against an X-ray crystal structure of FP-2 using the Glide docking program. An enrichment study was performed to select a suitable scoring function and to retrieve potential candidates against FP-2 from a large chemical database. Biological evaluation of 50 selected compounds identified 21 diverse nonpeptidic inhibitors of FP-2 with a hit rate of 42%. Atomic Fukui indices were used to predict the most electrophilic center and its electrophilicity in the identified hits. Comparison of predicted electrophilicity of electrophiles in identified hits with those in known irreversible inhibitors suggested the soft-nature of electrophiles in the selected target compounds. The present study highlights the importance of focused libraries and enrichment studies in structure-based virtual screening. In addition, few compounds were screened against homologous human cysteine proteases for selectivity analysis. Further evaluation of structure-activity relationships around these nonpeptidic scaffolds could help in the development of selective leads for antimalarial chemotherapy.

  12. Membrane topology and identification of key residues of EaDAcT, a plant MBOAT with unusual substrate specificity.

    Science.gov (United States)

    Tran, Tam N T; Shelton, Jennifer; Brown, Susan; Durrett, Timothy P

    2017-10-01

    Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) catalyzes the transfer of an acetyl group from acetyl-CoA to the sn-3 position of diacylglycerol to form 3-acetyl-1,2-diacyl-sn-glycerol (acetyl-TAG). EaDAcT belongs to a small, plant-specific subfamily of the membrane bound O-acyltransferases (MBOAT) that acylate different lipid substrates. Sucrose gradient density centrifugation revealed that EaDAcT colocalizes to the same fractions as an endoplasmic reticulum (ER)-specific marker. By mapping the membrane topology of EaDAcT, we obtained an experimentally determined topology model for a plant MBOAT. The EaDAcT model contains four transmembrane domains (TMDs), with both the N- and C-termini orientated toward the lumen of the ER. In addition, there is a large cytoplasmic loop between the first and second TMDs, with the MBOAT signature region of the protein embedded in the third TMD close to the interface between the membrane and the cytoplasm. During topology mapping, we discovered two cysteine residues (C187 and C293) located on opposite sides of the membrane that are important for enzyme activity. In order to identify additional amino acid residues important for acetyltransferase activity, we isolated and characterized acetyltransferases from other acetyl-TAG-producing plants. Among them, the acetyltransferase from Euonymus fortunei possessed the highest activity in vivo and in vitro. Mutagenesis of conserved amino acids revealed that S253, H257, D258 and V263 are essential for EaDAcT activity. Alteration of residues unique to the acetyltransferases did not alter the unique acyl donor specificity of EaDAcT, suggesting that multiple amino acids are important for substrate recognition. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  13. Identifying SARS-CoV membrane protein amino acid residues linked to virus-like particle assembly.

    Directory of Open Access Journals (Sweden)

    Ying-Tzu Tseng

    Full Text Available Severe acute respiratory syndrome coronavirus (SARS-CoV membrane (M proteins are capable of self-assembly and release in the form of membrane-enveloped vesicles, and of forming virus-like particles (VLPs when coexpressed with SARS-CoV nucleocapsid (N protein. According to previous deletion analyses, M self-assembly involves multiple M sequence regions. To identify important M amino acid residues for VLP assembly, we coexpressed N with multiple M mutants containing substitution mutations at the amino-terminal ectodomain, carboxyl-terminal endodomain, or transmembrane segments. Our results indicate that a dileucine motif in the endodomain tail (218LL219 is required for efficient N packaging into VLPs. Results from cross-linking VLP analyses suggest that the cysteine residues 63, 85 and 158 are not in close proximity to the M dimer interface. We noted a significant reduction in M secretion due to serine replacement for C158, but not for C63 or C85. Further analysis suggests that C158 is involved in M-N interaction. In addition to mutations of the highly conserved 107-SWWSFNPE-114 motif, substitutions at codons W19, W57, P58, W91, Y94 or F95 all resulted in significantly reduced VLP yields, largely due to defective M secretion. VLP production was not significantly affected by a tryptophan replacement of Y94 or F95 or a phenylalanine replacement of W19, W57 or W91. Combined, these results indicate the involvement of specific M amino acids during SARS-CoV virus assembly, and suggest that aromatic residue retention at specific positions is critical for M function in terms of directing virus assembly.

  14. Convergence of a residual based artificial viscosity finite element method

    KAUST Repository

    Nazarov, Murtazo

    2013-02-01

    We present a residual based artificial viscosity finite element method to solve conservation laws. The Galerkin approximation is stabilized by only residual based artificial viscosity, without any least-squares, SUPG, or streamline diffusion terms. We prove convergence of the method, applied to a scalar conservation law in two space dimensions, toward an unique entropy solution for implicit time stepping schemes. © 2012 Elsevier B.V. All rights reserved.

  15. A novel potentiometric biosensor for selective L-cysteine determination using L-cysteine-desulfhydrase producing Trichosporon jirovecii yeast cells coupled with sulfide electrode

    International Nuclear Information System (INIS)

    Hassan, Saad S.M.; El-Baz, Ashraf F.; Abd-Rabboh, Hisham S.M.

    2007-01-01

    Trichosporon jirovecii yeast cells are used for the first time as a source of L-cysteine desulfhydrase enzyme (EC 4.4.1.1) and incorporated in a biosensor for determining L-cysteine. The cells are grown under cadmium stress conditions to increase the expression level of the enzyme. The intact cells are immobilized on the membrane of a solid-state Ag 2 S electrode to provide a simple L-cysteine responsive biosensor. Upon immersion of the sensor in L-cysteine containing solutions, L-cysteine undergoes enzymatic hydrolysis into pyruvate, ammonia and sulfide ion. The rate of sulfide ion formation is potentiometrically measured as a function of L-cysteine concentration. Under optimized conditions (phosphate buffer pH 7, temperature 37 ± 1 deg. C and actual weight of immobilized yeast cells 100 mg), a linear relationship between L-cysteine concentration and the initial rate of sulfide liberation (dE/dt) is obtained. The sensor response covers the concentration range of 0.2-150 mg L -1 (1.7-1250 μmol L -1 ) L-cysteine. Validation of the assay method according to the quality control/quality assurance standards (precision, accuracy, between-day variability, within-day reproducibility, range of measurements and lower limit of detection) reveals remarkable performance characteristics of the proposed biosensor. The sensor is satisfactorily utilized for determination of L-cysteine in some pharmaceutical formulations. The lower limit of detection is ∼1 μmol L -1 and the accuracy and precision of the method are 97.5% and ±1.1%, respectively. Structurally similar sulfur containing compounds such as glutathione, cystine, methionine, and D-cysteine do no interfere

  16. Functionalization with C-terminal cysteine enhances transfection efficiency of cell-penetrating peptides through dimer formation

    Energy Technology Data Exchange (ETDEWEB)

    Amand, Helene L., E-mail: helene.amand@chalmers.se [Chalmers University of Technology, Department of Chemical and Biological Engineering/Physical Chemistry, SE-412 96 Gothenburg (Sweden); Norden, Bengt, E-mail: norden@chalmers.se [Chalmers University of Technology, Department of Chemical and Biological Engineering/Physical Chemistry, SE-412 96 Gothenburg (Sweden); Fant, Kristina, E-mail: kristina.fant@sp.se [Chalmers University of Technology, Department of Chemical and Biological Engineering/Physical Chemistry, SE-412 96 Gothenburg (Sweden)

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer Reversible CPP dimerisation is a simple yet efficient strategy to improve delivery. Black-Right-Pointing-Pointer Dimer formation enhances peptiplex stability, resulting in increased transfection. Black-Right-Pointing-Pointer By dimerisation, the CPP EB1 even gain endosomal escape properties while lowering cytotoxicity. -- Abstract: Cell-penetrating peptides have the ability to stimulate uptake of macromolecular cargo in mammalian cells in a non-toxic manner and therefore hold promise as efficient and well tolerated gene delivery vectors. Non-covalent peptide-DNA complexes ('peptiplexes') enter cells via endocytosis, but poor peptiplex stability and endosomal entrapment are considered as main barriers to peptide-mediated delivery. We explore a simple, yet highly efficient, strategy to improve the function of peptide-based vectors, by adding one terminal cysteine residue. This allows the peptide to dimerize by disulfide bond formation, increasing its affinity for nucleic acids by the 'chelate effect' and, when the bond is reduced intracellularly, letting the complex dissociate to deliver the nucleic acid. By introducing a single C-terminal cysteine in the classical CPP penetratin and the penetratin analogs PenArg and EB1, we show that this minor modification greatly enhances the transfection capacity for plasmid DNA in HEK293T cells. We conclude that this effect is mainly due to enhanced thermodynamic stability of the peptiplexes as endosome-disruptive chloroquine is still required for transfection and the effect is more pronounced for peptides with lower inherent DNA condensation capacity. Interestingly, for EB1, addition of one cysteine makes the peptide able to mediate transfection in absence of chloroquine, indicating that dimerisation can also improve endosomal escape properties. Further, the cytotoxicity of EB1 peptiplexes is considerably reduced, possibly due to lower concentration of free peptide

  17. Functionalization with C-terminal cysteine enhances transfection efficiency of cell-penetrating peptides through dimer formation

    International Nuclear Information System (INIS)

    Åmand, Helene L.; Nordén, Bengt; Fant, Kristina

    2012-01-01

    Highlights: ► Reversible CPP dimerisation is a simple yet efficient strategy to improve delivery. ► Dimer formation enhances peptiplex stability, resulting in increased transfection. ► By dimerisation, the CPP EB1 even gain endosomal escape properties while lowering cytotoxicity. -- Abstract: Cell-penetrating peptides have the ability to stimulate uptake of macromolecular cargo in mammalian cells in a non-toxic manner and therefore hold promise as efficient and well tolerated gene delivery vectors. Non-covalent peptide-DNA complexes (“peptiplexes”) enter cells via endocytosis, but poor peptiplex stability and endosomal entrapment are considered as main barriers to peptide-mediated delivery. We explore a simple, yet highly efficient, strategy to improve the function of peptide-based vectors, by adding one terminal cysteine residue. This allows the peptide to dimerize by disulfide bond formation, increasing its affinity for nucleic acids by the “chelate effect” and, when the bond is reduced intracellularly, letting the complex dissociate to deliver the nucleic acid. By introducing a single C-terminal cysteine in the classical CPP penetratin and the penetratin analogs PenArg and EB1, we show that this minor modification greatly enhances the transfection capacity for plasmid DNA in HEK293T cells. We conclude that this effect is mainly due to enhanced thermodynamic stability of the peptiplexes as endosome-disruptive chloroquine is still required for transfection and the effect is more pronounced for peptides with lower inherent DNA condensation capacity. Interestingly, for EB1, addition of one cysteine makes the peptide able to mediate transfection in absence of chloroquine, indicating that dimerisation can also improve endosomal escape properties. Further, the cytotoxicity of EB1 peptiplexes is considerably reduced, possibly due to lower concentration of free peptide dimer resulting from its stronger binding to DNA.

  18. Enhancement of thioredoxin/glutaredoxin-mediated L-cysteine synthesis from S-sulfocysteine increases L-cysteine production in Escherichia coli

    Science.gov (United States)

    2012-01-01

    Background Escherichia coli has two L-cysteine biosynthetic pathways; one is synthesized from O-acetyl L-serine (OAS) and sulfate by L-cysteine synthase (CysK), and another is produced via S-sulfocysteine (SSC) from OAS and thiosulfate by SSC synthase (CysM). SSC is converted into L-cysteine and sulfite by an uncharacterized reaction. As thioredoxins (Trx1 and Trx2) and glutaredoxins (Grx1, Grx2, Grx3, Grx4, and NrdH) are known as reductases of peptidyl disulfides, overexpression of such reductases might be a good way for improving L-cysteine production to accelerate the reduction of SSC in E. coli. Results Because the redox enzymes can reduce the disulfide that forms on proteins, we first tested whether these enzymes catalyze the reduction of SSC to L-cysteine. All His-tagged recombinant enzymes, except for Grx4, efficiently convert SSC into L-cysteine in vitro. Overexpression of Grx1 and NrdH enhanced a 15-40% increase in the E. coliL-cysteine production. On the other hand, disruption of the cysM gene cancelled the effect caused by the overexpression of Grx1 and NrdH, suggesting that its improvement was due to the efficient reduction of SSC under the fermentative conditions. Moreover, L-cysteine production in knockout mutants of the sulfite reductase genes (ΔcysI and ΔcysJ) and the L-cysteine synthase gene (ΔcysK) each decreased to about 50% of that in the wild-type strain. Interestingly, there was no significant difference in L-cysteine production between wild-type strain and gene deletion mutant of the upstream pathway of sulfite (ΔcysC or ΔcysH). These results indicate that sulfite generated from the SSC reduction is available as the sulfur source to produce additional L-cysteine molecule. It was finally found that in the E. coliL-cysteine producer that co-overexpress glutaredoxin (NrdH), sulfite reductase (CysI), and L-cysteine synthase (CysK), there was the highest amount of L-cysteine produced per cell. Conclusions In this work, we showed that Grx1 and

  19. Site-directed mutagenesis and molecular modelling studies show the role of Asp82 and cysteines in rat acylase 1, a member of the M20 family

    International Nuclear Information System (INIS)

    Herga, Sameh; Brutus, Alexandre; Vitale, Rosa Maria; Miche, Helene; Perrier, Josette; Puigserver, Antoine; Scaloni, Andrea; Giardina, Thierry

    2005-01-01

    Acylase 1 from rat kidney catalyzes the hydrolysis of acyl-amino acids. Sequence alignment has shown that this enzyme belongs to the metalloprotein family M20. Site-directed mutagenesis experiments led to the identification of one functionally important amino acid residue located near one of the zinc coordinating residues, which play a critical role in the enzymatic activity. The D82N- and D82E-substituted forms showed no significant activity and very low activity, respectively, along with a loss of zinc coordination. Molecular modelling investigations indicated a putative role of D82 in ensuring a proper protonation of catalytic histidine. In addition, none of the five cysteine residues present in the rat kidney acylase 1 sequence seemed involved in the catalytic process: the loss of activity induced by the C294A substitution was probably due to a conformational change in the 3D structure

  20. A C-terminal, cysteine-rich site in poliovirus 2C(ATPase) is required for morphogenesis.

    Science.gov (United States)

    Wang, Chunling; Ma, Hsin-Chieh; Wimmer, Eckard; Jiang, Ping; Paul, Aniko V

    2014-06-01

    The morphogenesis of viruses belonging to the genus Enterovirus in the family Picornaviridae is still poorly understood despite decades-long investigations. However, we recently provided evidence that 2C(ATPase) gives specificity to poliovirus encapsidation through an interaction with capsid protein VP3. The polypeptide 2C(ATPase) is a highly conserved non-structural protein of enteroviruses with important roles in RNA replication, encapsidation and uncoating. We have identified a site (K279/R280) near the C terminus of the polypeptide that is required for morphogenesis. The aim of the current project was to search for additional functional sites near the C terminus of the 2C(ATPase) polypeptide, with particular interest in those that are required for encapsidation. We selected for analysis a cysteine-rich site of the polypeptide and constructed four mutants in which cysteines or a histidine was changed to an alanine. The RNA transcripts were transfected into HeLa cells yielding two lethal, one temperature-sensitive and one quasi-infectious mutants. All four mutants exhibited normal protein translation in vitro and three of them possessed severe RNA replication defects. The quasi-infectious mutant (C286A) yielded variants with a pseudo-reversion at the original site (A286D), but some also contained one additional mutation: A138V or M293V. The temperature-sensitive mutant (C272A/H273A) exhibited an encapsidation and possibly also an uncoating defect at 37 °C. Variants of this mutant revealed suppressor mutations at three different sites in the 2C(ATPase) polypeptide: A138V, M293V and K295R. We concluded that the cysteine-rich site near the C terminus of 2C(ATPase) is involved in encapsidation, possibly through an interaction with an upstream segment located between boxes A and B of the nucleotide-binding domain. © 2014 The Authors.

  1. Activated human CD4 T cells express transporters for both cysteine and cystine

    DEFF Research Database (Denmark)

    Levring, Trine Bøegh; Hansen, Ann Kathrine; Nielsen, Bodil Lisbeth

    2012-01-01

    Because naïve T cells are unable to import cystine due to the absence of cystine transporters, it has been suggested that T cell activation is dependent on cysteine generated by antigen presenting cells. The aim of this study was to determine at which phases during T cell activation exogenous...... cystine/cysteine is required and how T cells meet this requirement. We found that early activation of T cells is independent of exogenous cystine/cysteine, whereas T cell proliferation is strictly dependent of uptake of exogenous cystine/cysteine. Naïve T cells express no or very low levels of both...... cystine and cysteine transporters. However, we found that these transporters become strongly up-regulated during T cell activation and provide activated T cells with the required amount of cystine/cysteine needed for T cell proliferation. Thus, T cells are equipped with mechanisms that allow T cell...

  2. Identification of redox-sensitive cysteines in the arabidopsis proteome using OxiTRAQ, a quantitative redox proteomics method

    KAUST Repository

    Liu, Pei

    2014-01-28

    Cellular redox status plays a key role in mediating various physiological and developmental processes often through modulating activities of redox-sensitive proteins. Various stresses trigger over-production of reactive oxygen/nitrogen species which lead to oxidative modifications of redox-sensitive proteins. Identification and characterization of redox-sensitive proteins are important steps toward understanding molecular mechanisms of stress responses. Here, we report a high-throughput quantitative proteomic approach termed OxiTRAQ for identifying proteins whose thiols undergo reversible oxidative modifications in Arabidopsis cells subjected to oxidative stress. In this approach, a biotinylated thiol-reactive reagent is used for differential labeling of reduced and oxidized thiols. The biotin-tagged peptides are affinity purified, labeled with iTRAQ reagents, and analyzed using a paralleled HCD-CID fragmentation mode in an LTQ-Orbitrap. With this approach, we identified 195 cysteine-containing peptides from 179 proteins whose thiols underwent oxidative modifications in Arabidopsis cells following the treatment with hydrogen peroxide. A majority of those redox-sensitive proteins, including several transcription factors, were not identified by previous redox proteomics studies. This approach allows identification of the specific redox-regulated cysteine residues, and offers an effective tool for elucidation of redox proteomes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Cysteine Supplementation May be Beneficial in a Subgroup of Mitochondrial Translation Deficiencies.

    Science.gov (United States)

    Bartsakoulia, Marina; Mϋller, Juliane S; Gomez-Duran, Aurora; Yu-Wai-Man, Patrick; Boczonadi, Veronika; Horvath, Rita

    2016-08-30

    Mitochondrial encephalomyopathies are severe, relentlessly progressive conditions and there are very few effective therapies available to date. We have previously suggested that in two rare forms of reversible mitochondrial disease (reversible infantile respiratory chain deficiency and reversible infantile hepatopathy) supplementation with L-cysteine can improve mitochondrial protein synthesis, since cysteine is required for the 2-thiomodification of mitochondrial tRNAs. We studied whether supplementation with L-cysteine or N-acetyl-cysteine (NAC) results in any improvement of the mitochondrial function in vitro in fibroblasts of patients with different genetic forms of abnormal mitochondrial translation. We studied in vitro in fibroblasts of patients carrying the common m.3243A>G and m.8344A>G mutations or autosomal recessive mutations in genes affecting mitochondrial translation, whether L-cysteine or N-acetyl-cysteine supplementation have an effect on mitochondrial respiratory chain function. Here we show that supplementation with L-cysteine, but not with N-acetyl-cysteine partially rescues the mitochondrial translation defect in vitro in fibroblasts of patients carrying the m.3243A>G and m.8344A>G mutations. In contrast, N-acetyl-cysteine had a beneficial effect on mitochondrial translation in TRMU and MTO1 deficient fibroblasts. Our results suggest that L-cysteine or N-acetyl-cysteine supplementation may be a potential treatment for selected subgroups of patients with mitochondrial translation deficiencies. Further studies are needed to explore the full potential of cysteine supplementation as a treatment for patients with mitochondrial disease.

  4. Enhancement of L-cysteine production by disruption of yciW in Escherichia coli.

    Science.gov (United States)

    Kawano, Yusuke; Ohtsu, Iwao; Takumi, Kazuhiro; Tamakoshi, Ai; Nonaka, Gen; Funahashi, Eri; Ihara, Masaki; Takagi, Hiroshi

    2015-02-01

    Using in silico analysis, the yciW gene of Escherichia coli was identified as a novel L-cysteine regulon that may be regulated by the transcriptional activator CysB for sulfur metabolic genes. We found that overexpression of yciW conferred tolerance to L-cysteine, but disruption of yciW increased L-cysteine production in E. coli. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. Effects of cysteine protease inhibitors on rabbit cathepsin D maturation

    International Nuclear Information System (INIS)

    Samarel, A.M.; Ferguson, A.G.; Decker, R.S.; Lesch, M.

    1989-01-01

    To examine the effects of cysteine protease inhibitors on cathepsin D intracellular transport, proteolytic processing, and secretion, primary cultures of rabbit cardiac fibroblasts were grown to confluence and exposed to media containing leupeptin, E 64, or chloroquine. Cathepsin D maturation was then evaluated in pulse-chase biosynthetic labeling experiments. None of the three agents affected the charge modification of procathepsin D within the Golgi apparatus. However, all three agents interfered with the subsequent proteolytic processing of procathepsin D isoforms to active cathepsin D. Both leupeptin and E 64 caused the intracellular accumulation of large amounts of a Mr 51,000 processing intermediate. Trace amounts of this intermediate were also detected in chloroquine-treated cells. Combined activity assay and radioimmunoassay of cell lysates indicated that this partially processed form of cathepsin D possessed proteolytic activity. Whereas low medium concentrations of leupeptin (10-100 microM) but not E 64 appeared to stimulate procathepsin D secretion, neither agent appeared to have a major effect on the rate of proenzyme secretion at doses required to inhibit proteolytic maturation (1-10 mM). Furthermore, pretreatment of cells with 10 mM leupeptin appeared only to delay, but not prevent, the intracellular transport of cathepsin D to lysosomes. In contrast, chloroquine increased procathepsin D secretion in a dose-dependent manner, diverting the majority of newly synthesized procathepsin D from the intracellular protease(s) responsible for proteolytic processing. These results suggest that cysteine proteases participate in the proteolytic maturation of procathepsin D during the transport of newly synthesized enzyme to lysosomes, but cysteine protease-mediated proteolytic processing is not required for cathepsin D activation or lysosomal translocation

  6. Effect of L-cysteine on the oxidation of cyclohexane catalyzed by manganeseporphyrin.

    Science.gov (United States)

    Zhou, Wei-You; Tian, Peng; Chen, Yong; He, Ming-Yang; Chen, Qun; Chen, Zai Xin

    2015-06-01

    Effect of L-cysteine as the cocatalyst on the oxidation of cyclohexane by tert-butylhydroperoxide (TBHP) catalyzed by manganese tetraphenylporphyrin (MnTPP) has been investigated. The results showed that L-cysteine could moderately improve the catalytic activity of MnTPP and significantly increase the selectivity of cyclohexanol. Different from imidazole and pyridine, the L-cysteine may perform dual roles in the catalytic oxidation of cyclohexane. Besides as the axial ligand for MnTPP, the L-cysteine could also react with cyclohexyl peroxide formed as the intermediate to produce alcohol as the main product. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. L-cysteine suppresses ghrelin and reduces appetite in rodents and humans.

    Science.gov (United States)

    McGavigan, A K; O'Hara, H C; Amin, A; Kinsey-Jones, J; Spreckley, E; Alamshah, A; Agahi, A; Banks, K; France, R; Hyberg, G; Wong, C; Bewick, G A; Gardiner, J V; Lehmann, A; Martin, N M; Ghatei, M A; Bloom, S R; Murphy, K G

    2015-03-01

    High-protein diets promote weight loss and subsequent weight maintenance, but are difficult to adhere to. The mechanisms by which protein exerts these effects remain unclear. However, the amino acids produced by protein digestion may have a role in driving protein-induced satiety. We tested the effects of a range of amino acids on food intake in rodents and identified l-cysteine as the most anorexigenic. Using rodents we further studied the effect of l-cysteine on food intake, behaviour and energy expenditure. We proceeded to investigate its effect on neuronal activation in the hypothalamus and brainstem before investigating its effect on gastric emptying and gut hormone release. The effect of l-cysteine on appetite scores and gut hormone release was then investigated in humans. l-Cysteine dose-dependently decreased food intake in both rats and mice following oral gavage and intraperitoneal administration. This effect did not appear to be secondary to behavioural or aversive side effects. l-Cysteine increased neuronal activation in the area postrema and delayed gastric emptying. It suppressed plasma acyl ghrelin levels and did not reduce food intake in transgenic ghrelin-overexpressing mice. Repeated l-cysteine administration decreased food intake in rats and obese mice. l-Cysteine reduced hunger and plasma acyl ghrelin levels in humans. Further work is required to determine the chronic effect of l-cysteine in rodents and humans on appetite and body weight, and whether l-cysteine contributes towards protein-induced satiety.

  8. Click-PEGylation - A mobility shift approach to assess the redox state of cysteines in candidate proteins.

    Science.gov (United States)

    van Leeuwen, Lucie A G; Hinchy, Elizabeth C; Murphy, Michael P; Robb, Ellen L; Cochemé, Helena M

    2017-07-01

    The redox state of cysteine thiols is critical for protein function. Whereas cysteines play an important role in the maintenance of protein structure through the formation of internal disulfides, their nucleophilic thiol groups can become oxidatively modified in response to diverse redox challenges and thereby function in signalling and antioxidant defences. These oxidative modifications occur in response to a range of agents and stimuli, and can lead to the existence of multiple redox states for a given protein. To assess the role(s) of a protein in redox signalling and antioxidant defence, it is thus vital to be able to assess which of the multiple thiol redox states are present and to investigate how these alter under different conditions. While this can be done by a range of mass spectrometric-based methods, these are time-consuming, costly, and best suited to study abundant proteins or to perform an unbiased proteomic screen. One approach that can facilitate a targeted assessment of candidate proteins, as well as proteins that are low in abundance or proteomically challenging, is by electrophoretic mobility shift assays. Redox-modified cysteine residues are selectively tagged with a large group, such as a polyethylene glycol (PEG) polymer, and then the proteins are separated by electrophoresis followed by immunoblotting, which allows the inference of redox changes based on band shifts. However, the applicability of this method has been impaired by the difficulty of cleanly modifying protein thiols by large PEG reagents. To establish a more robust method for redox-selective PEGylation, we have utilised a Click chemistry approach, where free thiol groups are first labelled with a reagent modified to contain an alkyne moiety, which is subsequently Click-reacted with a PEG molecule containing a complementary azide function. This strategy can be adapted to study reversibly reduced or oxidised cysteines. Separation of the thiol labelling step from the PEG

  9. Producing armyworm (spodoptera sp.) Bioinsecticide based on cysteine protease of red ginger (zingiber officinale var. Rubrum)

    Science.gov (United States)

    Afnan, N. T.; Nur, D. F.; Utami, T. S.; Sahlan, M.; Wijanarko, A.; Hermansyah, H.

    2018-03-01

    Armyworm (Spodoptera sp.) is highly polyphagous defoliator on various horticulture and grain plants. Various chemical insecticides have been created to control it. There is a need to create an eco-friendly and specific insecticide which only affect armyworm’s nervous system. This research investigates cysteine-protease’s enzyme activity of red ginger (Zingiber officinale var. Rubrum) which is called zingibain. Its catalytic site matches with residue site in armyworm’s body so it can be used as bioinsecticide raw material which meets the criterias above. Fresh red ginger rhizomes were washed and extracted. The juice was then deposited in low temperature and centrifuged to get rid of its starch content. It was filtrated to remove large contaminants and poured into Potassium Phospate buffer. The liquid was then centrifuged again for 30 minutes before collecting the supernatant. Fresh leaves were then dipped into crude ginger protease extract and fed to fourth instar-armyworms. Leaves dipped into non-diluted extract were barely eaten by armyworm while the 50% and 25% dilution was half eaten and most eaten. The crude red ginger extract was not strong enough to kill them although the research showed its enzymatic activity reaches up to 169 PU. It still needs improvement to be produced as commercial bioinsecticide.

  10. The apotheosis of conservation agriculture- A review

    OpenAIRE

    Hossain, M.M.

    2013-01-01

    This paper focuses on conservation agriculture (CA), defined as minimal soil disturbance (no-till) and crop residue retention (mulch) combined with crop rotations. The paper then describes the principles based on which CA runs with briefing suggested improvement on conservation tillage, where no-till, mulch and rotations significantly improve soil properties and other biotic factors. This paper also describes some cons of CA with its future strategies. A Case study from the rice-wheat areas o...

  11. Kit formulation for 99mTc-labeling of recombinant Annexin V molecule with a C-terminally engineered cysteine

    International Nuclear Information System (INIS)

    Chunxiong Lu; Quanfu Jiang; Cheng Tan; Huixin Yu; Minjin Hu; Zichun Hua; Nanjing University, Nanjing

    2015-01-01

    A new formulation of a freeze-dried kit for the labeling of a novel recombinant Annexin V molecules (with a single cysteine residue at its C-terminal, Cys-Annexin V) with technetium-99m has been developed. Effects of the amount range of Cys-Annexin V, stannous chloride, glucoheptonate and disodium edetate on the radiolabeling yield were studied in details. The stabilities of 99m Tc-Cys-Annexin V and freeze-dried kits were performed, respectively. In vitro cell uptake studies showed the binding of 99m Tc-Cys-Annexin V was specific on testing with apoptotic H446 cells. Therefore, 99m Tc-Cys-Annexin V is a potential apoptosis imaging agent and further study is needed. (author)

  12. Immunological cross-reactivity of the major allergen from perennial ryegrass (Lolium perenne), Lol p I, and the cysteine proteinase, bromelain.

    Science.gov (United States)

    Pike, R N; Bagarozzi, D; Travis, J

    1997-04-01

    Antibodies prepared in rabbits against the major allergen from ryegrass (Lolium perenne), Lol p I, cross-reacted with the cysteine proteinase bromelain from pineapple and vice versa. Deglycosylation of the proteins showed that the cross-reaction was based on recognition of the carbohydrate moiety of the allergen, but for bromelain the cross-reaction was most likely due to a combination of factors. The results indicate that the carbohydrate residues from these allergens play an important role in cross-reactions found between them and possibly those from other species.

  13. Copper oxide assisted cysteine hierarchical structures for immunosensor application

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Chandra Mouli [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005 (India); Sumana, Gajjala, E-mail: sumanagajjala@gmail.com [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Tiwari, Ida [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005 (India)

    2014-09-08

    The present work describes the promising electrochemical immunosensing strategy based on copper (II) assisted hierarchical cysteine structures (CuCys) varying from star to flower like morphology. The CuCys having average size of 10 μm have been synthesised using L-Cysteine as initial precursor in presence of copper oxide under environmentally friendly conditions in aqueous medium. To delineate the synthesis mechanism, detailed structural investigations have been carried out using characterization techniques such as X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The electrochemical behaviour of self-assembled CuCys on gold electrode shows surface controlled electrode reaction with an apparent electron transfer rate constant of 3.38 × 10{sup −4 }cm s{sup −1}. This innovative platform has been utilized to fabricate an immunosensor by covalently immobilizing monoclonal antibodies specific for Escherichia coli O157:H7 (E. coli). Under the optimal conditions, the fabricated immunosensor is found to be sensitive and specific for the detection of E. coli with a detection limit of 10 cfu/ml.

  14. The structure of the cysteine protease and lectin-like domains of Cwp84, a surface layer-associated protein from Clostridium difficile

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, William J. [University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Public Health England, Porton Down, Salisbury SP4 0JG (United Kingdom); Kirby, Jonathan M. [Public Health England, Porton Down, Salisbury SP4 0JG (United Kingdom); Thiyagarajan, Nethaji [University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Chambers, Christopher J.; Davies, Abigail H. [University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Public Health England, Porton Down, Salisbury SP4 0JG (United Kingdom); Roberts, April K.; Shone, Clifford C. [Public Health England, Porton Down, Salisbury SP4 0JG (United Kingdom); Acharya, K. Ravi, E-mail: bsskra@bath.ac.uk [University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)

    2014-07-01

    The crystal structure of Cwp84, an S-layer protein from Clostridium difficile is presented for the first time. The cathepsin L-like fold of cysteine protease domain, a newly observed ‘lectin-like’ domain and several other features are described. Clostridium difficile is a major problem as an aetiological agent for antibiotic-associated diarrhoea. The mechanism by which the bacterium colonizes the gut during infection is poorly understood, but undoubtedly involves a myriad of components present on the bacterial surface. The mechanism of C. difficile surface-layer (S-layer) biogenesis is also largely unknown but involves the post-translational cleavage of a single polypeptide (surface-layer protein A; SlpA) into low- and high-molecular-weight subunits by Cwp84, a surface-located cysteine protease. Here, the first crystal structure of the surface protein Cwp84 is described at 1.4 Å resolution and the key structural components are identified. The truncated Cwp84 active-site mutant (amino-acid residues 33–497; C116A) exhibits three regions: a cleavable propeptide and a cysteine protease domain which exhibits a cathepsin L-like fold followed by a newly identified putative carbohydrate-binding domain with a bound calcium ion, which is referred to here as a lectin-like domain. This study thus provides the first structural insights into Cwp84 and a strong base to elucidate its role in the C. difficile S-layer maturation mechanism.

  15. The structure of the cysteine protease and lectin-like domains of Cwp84, a surface layer-associated protein from Clostridium difficile

    International Nuclear Information System (INIS)

    Bradshaw, William J.; Kirby, Jonathan M.; Thiyagarajan, Nethaji; Chambers, Christopher J.; Davies, Abigail H.; Roberts, April K.; Shone, Clifford C.; Acharya, K. Ravi

    2014-01-01

    The crystal structure of Cwp84, an S-layer protein from Clostridium difficile is presented for the first time. The cathepsin L-like fold of cysteine protease domain, a newly observed ‘lectin-like’ domain and several other features are described. Clostridium difficile is a major problem as an aetiological agent for antibiotic-associated diarrhoea. The mechanism by which the bacterium colonizes the gut during infection is poorly understood, but undoubtedly involves a myriad of components present on the bacterial surface. The mechanism of C. difficile surface-layer (S-layer) biogenesis is also largely unknown but involves the post-translational cleavage of a single polypeptide (surface-layer protein A; SlpA) into low- and high-molecular-weight subunits by Cwp84, a surface-located cysteine protease. Here, the first crystal structure of the surface protein Cwp84 is described at 1.4 Å resolution and the key structural components are identified. The truncated Cwp84 active-site mutant (amino-acid residues 33–497; C116A) exhibits three regions: a cleavable propeptide and a cysteine protease domain which exhibits a cathepsin L-like fold followed by a newly identified putative carbohydrate-binding domain with a bound calcium ion, which is referred to here as a lectin-like domain. This study thus provides the first structural insights into Cwp84 and a strong base to elucidate its role in the C. difficile S-layer maturation mechanism

  16. Loss of the nodule-specific cysteine rich peptide, NCR169, abolishes symbiotic nitrogen fixation in the Medicago truncatula dnf7 mutant.

    Science.gov (United States)

    Horváth, Beatrix; Domonkos, Ágota; Kereszt, Attila; Szűcs, Attila; Ábrahám, Edit; Ayaydin, Ferhan; Bóka, Károly; Chen, Yuhui; Chen, Rujin; Murray, Jeremy D; Udvardi, Michael K; Kondorosi, Éva; Kaló, Péter

    2015-12-08

    Host compatible rhizobia induce the formation of legume root nodules, symbiotic organs within which intracellular bacteria are present in plant-derived membrane compartments termed symbiosomes. In Medicago truncatula nodules, the Sinorhizobium microsymbionts undergo an irreversible differentiation process leading to the development of elongated polyploid noncultivable nitrogen fixing bacteroids that convert atmospheric dinitrogen into ammonia. This terminal differentiation is directed by the host plant and involves hundreds of nodule specific cysteine-rich peptides (NCRs). Except for certain in vitro activities of cationic peptides, the functional roles of individual NCR peptides in planta are not known. In this study, we demonstrate that the inability of M. truncatula dnf7 mutants to fix nitrogen is due to inactivation of a single NCR peptide, NCR169. In the absence of NCR169, bacterial differentiation was impaired and was associated with early senescence of the symbiotic cells. Introduction of the NCR169 gene into the dnf7-2/NCR169 deletion mutant restored symbiotic nitrogen fixation. Replacement of any of the cysteine residues in the NCR169 peptide with serine rendered it incapable of complementation, demonstrating an absolute requirement for all cysteines in planta. NCR169 was induced in the cell layers in which bacteroid elongation was most pronounced, and high expression persisted throughout the nitrogen-fixing nodule zone. Our results provide evidence for an essential role of NCR169 in the differentiation and persistence of nitrogen fixing bacteroids in M. truncatula.

  17. ESR investigation of the reactions of glutathione, cysteine and penicillamine thiyl radicals: competitive formation of RSOcenter dot, Rcenter dot, RSSRcenter dot-. , and RSScenter dot

    Energy Technology Data Exchange (ETDEWEB)

    Becker, David; Swarts, Steven; Champagne, Mark; Sevilla, M D

    1988-05-01

    The reactions of cysteine, glutathione and penicillamine thiyl radicals with oxygen and their parent thiols in frozen solutions have been elucidated with e.s.r. The major sulfur radicals observed are: (1) thiyl radicals, RS center dot; (2) disulfide radical anions, RSSR anion radicals; (3) perthiyl radicals, RSS center dot and upon introduction of oxygen; (4) sulfinyl radicals, RSO center dot, where R represents the remainder of the cysteine, glutathione or penicillamine moiety. The radical product observed depends on pH, concentration of thiol, and presence or absence of molecular oxygen. The sulfinyl radical is a ubiquitous intermediate, peroxyl radical attack on thiols may lead to sulfinyl radicals. The authors elaborate the observed reaction sequences that lead to sulfinyl radicals and, using /sup 17/O isotopic substitution studies, demonstrate the oxygen atom in sulfinyl radicals originates from dissolved molecular oxygen. The glutathione radical is found to abstract hydrogen from the ..cap alpha..-carbon position on the cysteine residue of glutathione to form a carbon-centred radical.

  18. Emission of hydrogen sulfide by leaf tissue in response to L-cysteine

    International Nuclear Information System (INIS)

    Sekiya, J.; Schmidt, A.; Wilson, L.G.; Filner, P.

    1982-01-01

    Leaf discs and detached leaves exposed to L-cysteine emitted a volatile sulfur compound which was proven by gas chromatography to be H 2 S. This phenomenon was demonstrated in all nine species tested (Cucumis sativus, Cucurbita pepo, Nicotiana tabacum, Coleus blumei, Beta vulgaris, Phaseolus vulgaris, Medicago sativa, Hordeum vulgare, and Gossypium hirsutum). The emission of volatile sulfur by cucumber leaves occurred in the dark at a similar rate to that in the light. The emission of leaf discs reached the maximal rate, more than 40 picomoles per minute per square centimeter, 2 to 4 hours after starting exposure to L-cysteine; then it decreased. In the case of detached leaves, the maximum occurred 5 to 10 h after starting exposure. The average emission rate of H 2 S during the first 4 hours from leaf discs of cucurbits in response to 10 millimolar L-cysteine, was usually more than 40 picomoles per minute per square centimeter, i.e. 0.24 micromoles per hour per square decimeter. Leaf discs exposed to 1 millimolar L-cysteine emitted only 2% as much as did the discs exposed to 10 millimolar L-cysteine. The emission from leaf discs and from detached leaves lasted for at least 5 and 15 hours, respectively. However, several hours after the maximal emission, injury of the leaves, manifested as chlorosis, was evident. H 2 S emission was a specific consequence of exposure to L-cysteine; neither D-cysteine nor L-cysteine elicited H 2 S emission. Aminooxyacetic acid, an inhibitor of pyridoxal phosphate dependent enzymes, inhibited the emission. In a cell free system from cucumber leaves, H 2 S formation and its release occurred in response to L-cysteine. Feeding experiments with [ 35 S]t-cysteine showed that most of the sulfur in H 2 S was derived from sulfur in the L-cysteine supplied

  19. Determination of free and total cyst(e)ine in plasma of dogs and cats.

    Science.gov (United States)

    Tôrres, Cristina L; Miller, Joshua W; Rogers, Quinton R

    2004-01-01

    In human blood, the amino acid cysteine forms disulfide bonds with itself and with other sulfhydryl compounds in their free form and with sulfhydryls in protein. Protein-bound cysteine is lost when plasma proteins are removed before amino acid analysis. The purpose of this study was to assess the time course and extent of cyst(e)ine (cysteine + half-cystine) loss in dog and cat plasma. An equal volume of 6% sulfosalicylic acid was added to plasma aliquots at 0, 2, 4, 10, 16, 24, 36, 48, 60, and 72 hours after separation of blood cells. Tris-2-carboxyethyl-phosphine hydrochloride (TCEP - HCl), a reducing agent, was used to regenerate total plasma cyst(e)ine after 3 months of sample storage (-20 degrees C). Initial free cyst(e)ine concentrations (mean +/- SEM) were higher in canine plasma (77 +/- 4 micromol/L) than in feline plasma (37 +/- 3 micromol/L). Free plasma cyst(e)ine concentrations in dogs and cats decreased after first-order kinetics, with a half-life of 23 and 69 hours, respectively. Total plasma cysteine after TCEP - HCl treatment was similar for dogs (290 micromol/L) and cats (296 micromol/L), but the percentage of free cysteine was higher (P = .02) in dogs (27%) than in cats (13%). Over half of the cyst(e)ine, homocysteine, cysteinylglycine, and glutathione were bound in vivo to plasma proteins. These results emphasize the importance of removing plasma proteins within 1 hour after blood collection for reliable assay of free plasma cyst(e)ine.

  20. NOA36 Protein Contains a Highly Conserved Nucleolar Localization Signal Capable of Directing Functional Proteins to the Nucleolus, in Mammalian Cells

    Science.gov (United States)

    de Melo, Ivan S.; Jimenez-Nuñez, Maria D.; Iglesias, Concepción; Campos-Caro, Antonio; Moreno-Sanchez, David; Ruiz, Felix A.; Bolívar, Jorge

    2013-01-01

    NOA36/ZNF330 is an evolutionarily well-preserved protein present in the nucleolus and mitochondria of mammalian cells. We have previously reported that the pro-apoptotic activity of this protein is mediated by a characteristic cysteine-rich domain. We now demonstrate that the nucleolar localization of NOA36 is due to a highly-conserved nucleolar localization signal (NoLS) present in residues 1–33. This NoLS is a sequence containing three clusters of two or three basic amino acids. We fused the amino terminal of NOA36 to eGFP in order to characterize this putative NoLS. We show that a cluster of three lysine residues at positions 3 to 5 within this sequence is critical for the nucleolar localization. We also demonstrate that the sequence as found in human is capable of directing eGFP to the nucleolus in several mammal, fish and insect cells. Moreover, this NoLS is capable of specifically directing the cytosolic yeast enzyme polyphosphatase to the target of the nucleolus of HeLa cells, wherein its enzymatic activity was detected. This NoLS could therefore serve as a very useful tool as a nucleolar marker and for directing particular proteins to the nucleolus in distant animal species. PMID:23516598

  1. Elimination of hydrogen sulphide and β substitution in cystein, catalyzed by the cysteine-lyase of hens yolk-sac and yolk (1961)

    International Nuclear Information System (INIS)

    Chapeville, F.; Fromageot, P.

    1961-01-01

    The yolk of incubated hen's eggs contains a pyridoxal phosphate activated enzyme, free of iron, copper, magnesium and calcium. This enzyme activates the β-carbon atom of cysteine. Its reactivity is demonstrated by the ease with which this β-carbon fixes various sulfur containing substances in which the sulfur has reducing properties: inorganic sulfide, sulfide or cysteine itself. In the absence of substances able to react with the β-carbon atom, the active complex, consisting of the enzyme and the aminated tri-carbon chain, is hydrolysed to pyruvic acid and ammonia. The liberation of hydrogen sulfide thus appears to be the consequence either of the substitution of the β-carbon atom of cysteine or of the decomposition of the complex which this aminoacid forms with the enzyme studied. The latter seems therefore to possess an activity which differs from the activity of the desulfhydrases as yet known. We suggest to call this enzyme cystein-lyase. (authors) [fr

  2. A novel, highly conserved metallothionein family in basidiomycete fungi and characterization of two representative SlMTa and SlMTb genes in the ectomycorrhizal fungus Suillus luteus.

    Science.gov (United States)

    Nguyen, Hoai; Rineau, François; Vangronsveld, Jaco; Cuypers, Ann; Colpaert, Jan V; Ruytinx, Joske

    2017-07-01

    The basidiomycete Suillus luteus is an important member of the ectomycorrhizal community that thrives in heavy metal polluted soils covered with pioneer pine forests. This study aimed to identify potential heavy metal chelators in S. luteus. Two metallothionein (MT) coding genes, SlMTa and SlMTb, were identified. When heterologously expressed in yeast, both SlMTa and SlMTb can rescue the Cu sensitive mutant from Cu toxicity. In S. luteus, transcription of both SlMTa and SlMTb is induced by Cu but not Cd or Zn. Several putative Cu-sensing and metal-response elements are present in the promoter sequences. These results indicate that SlMTa and SlMTb function as Cu-thioneins. Homologs of the S. luteus MTs are present in 49 species belonging to 10 different orders of the subphylum Agaricomycotina and are remarkably conserved. The length of the proteins, number and distribution of cysteine residues indicate a novel family of fungal MTs. The ubiquitous and highly conserved features of these MTs suggest that they are important for basic cellular functions in species in the subphylum Agaricomycotina. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  3. Cardiovascular actions of L-cysteine and L-cysteine sulfinic acid in the nucleus tractus solitarius of the rat.

    Science.gov (United States)

    Takemoto, Yumi

    2014-07-01

    The sulfur-containing excitatory amino acid (EAA) L-cysteine sulfinic acid (CSA), a neurotransmitter candidate, is endogenously synthesized from L-cysteine (Cys). Exogenous Cys administration into the brain produces cardiovascular effects; these effects likely occur via synaptic stimulation of central nervous system (CNS) neurons that regulate peripheral cardiovascular function. However, the cardiovascular responses produced by CNS Cys administration could result from CSA biosynthesized in synapse. The present study examined the role of CSA in Cys-induced cardiovascular responses within the nucleus tractus solitarius (NTS) of anesthetized rats. The NTS receives input from various visceral afferents that gate autonomic reflexes, including cardiovascular reflexes. Within the NTS, both Cys and CSA microinjections produced decrease responses in arterial blood pressure and heart rate that were similar to those produced by L-glutamate. Co-injection of the ionotropic EAA receptor antagonist kynurenic acid abolished Cys-, but not CSA-, induced cardiovascular responses. This finding suggests that only Cys-induced cardiovascular responses are mediated by kynurenate-sensitive receptors. This study provides the first demonstration that Cys- and CSA-induced cardiovascular responses occur via different mechanisms in the NTS of rats. Further, this study also indicates that Cys-induced cardiovascular responses do not occur via CSA. Thus, within the NTS, endogenous Cys and/or CSA might be involved in cardiovascular regulation.

  4. Alleviative effects of s-allyl cysteine and s-ethyl cysteine on MCD diet-induced hepatotoxicity in mice.

    Science.gov (United States)

    Lin, Chun-che; Yin, Mei-chin; Liu, Wen-hu

    2008-11-01

    Alleviative effects of s-allyl cysteine (SAC) and s-ethyl cysteine (SEC) upon methionine and choline deficient (MCD) diet-induced hepatotoxicity in mice were examined. SAC or SEC at 1g/L was added into drinking water for 7 weeks with MCD diet. MCD feeding significantly increased hepatic triglyceride and cholesterol levels, and elevated the activity of glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme, fatty acid synthase (FAS) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (P MCD feeding significantly lowered serum and hepatic glutathione (GSH) levels, increased malondialdehyde (MDA) and oxidized glutathione (GSSG) formation, and suppressed the activity and mRNA expression of glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (P MCD feeding significantly enhanced the mRNA expression of interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta1, matrix metalloproteinases-9 (MMP-9) and collagen-alpha1 (P MCD-induced hepatotoxicity.

  5. Post meningitis subdural hygroma: Anatomical and functional evaluation with (99m)Tc-ehylene cysteine dimer single photon emission tomography/computed tomography.

    Science.gov (United States)

    Sharma, Punit; Mishra, Ajiv; Arora, Geetanjali; Tripathi, Madhavi; Bal, Chandrasekhar; Kumar, Rakesh

    2013-01-01

    Subdural hygroma is the collection of cerebrospinal fluid in the subdural space. Most often these resolve spontaneously. However, in cases with neurological complications surgical drainage may be needed. We here, present the case of an 8-year-old boy with post meningitis subdural hygroma. (99m)Tc-ehylene cysteine dimer ((99m)Tc-ECD) hybrid single photon emission tomography/computed tomography (SPECT/CT) carried out in this patient, demonstrated the subdural hygroma as well as the associated cerebral hypoperfusion. If (99m)Tc-ECD SPECT/CT is integrated into management of these patients, it can help in decision making with respect to conservative versus surgical management.

  6. Identification of cis-elements for ethylene and circadian regulation of the Solanum melongena gene encoding cysteine proteinase.

    Science.gov (United States)

    Rawat, Reetika; Xu, Zeng-Fu; Yao, Kwok-Ming; Chye, Mee-Len

    2005-03-01

    We have previously shown that the expression of SmCP which encodes Solanum melongena cysteine proteinase is ethylene-inducible and is under circadian control. To understand the regulation of SmCP, a 1.34-kb SmCP 5'-flanking region and its deletion derivatives were analyzed for cis-elements using GUS and luc fusions and by in vitro binding assays. Analysis of transgenic tobacco transformed with SmCP promoter-GUS constructs confirmed that the promoter region -415/+54 containing Ethylene Responsive Element ERE(-355/-348) conferred threefold ethylene-induction of GUS expression, while -827/+54 which also contains ERE(-683/-676), produced fivefold induction. Using gel mobility shift assays, we demonstrated that each ERE binds nuclear proteins from both ethephon-treated and untreated 5-week-old seedlings, suggesting that different transcriptions factors bind each ERE under varying physiological conditions. Binding was also observed in extracts from senescent, but not young, fruits. The variation in binding at the EREs in fruits and seedlings imply that organ-specific factors may participate in binding. Analysis of transgenic tobacco expressing various SmCP promoter-luc constructs containing wild-type or mutant Evening Elements (EEs) confirmed that both conserved EEs at -795/-787 and -785/-777 are important in circadian control. We confirmed the binding of total nuclear proteins to EEs in gel mobility shift assays and in DNase I footprinting. Our results suggest that multiple proteins bind the EEs which are conserved in plants other than Arabidopsis and that functional EEs and EREs are present in the 5'-flanking region of a gene encoding cysteine proteinase.

  7. Tuning the carbon nanotube photoluminescence enhancement at addition of cysteine through the change of external conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kurnosov, N.V.; Karachevtsev, M.V.; Leontiev, V.S.; Karachevtsev, V.A., E-mail: karachevtsev@ilt.kharkov.ua

    2017-01-15

    The enhancement of the photoluminescence (PL) from the semiconducting single-walled carbon nanotubes suspended with single-stranded DNA (ssDNA) in water observed after amino acids doping is the largest at cysteine addition. The PL intensity increased through the passivation of p-defects on the carbon nanotube sidewall by the cysteine molecules due to thiol group. The effect of several external factors on the cysteine-induced enhancement of PL from carbon nanotubes covered with ssDNA was studied: UV irradiation, tip or bath sonication treatment of the suspension, the ionic strength and pH of aqueous suspension. It turned out that all these factors have an essential influence on the dependence of the PL enhancement on the cysteine concentration through inducing of additional defects on nanotube as well as a change of the nanotube surface coverage with polymer. The obtained experimental results demonstrated that PL from carbon nanotubes can be exploited successfully for the monitoring of cysteine concentration in aqueous solution. - Highlights: • Cysteine doping enhances carbon nanotube emission more than other amino acids do. • SWNT emission dependence on cysteine concentration is tuned by UV irradiation and pH. • Type of sonication treatment influences SWNT PL dependence on cysteine concentration. • Polymer coverage and defectiveness of nanotubes effect on nanotube emission. • Graphic abstract.

  8. Neuronal growth on L- and D-cysteine self-assembled monolayers reveals neuronal chiral sensitivity.

    Science.gov (United States)

    Baranes, Koby; Moshe, Hagay; Alon, Noa; Schwartz, Shmulik; Shefi, Orit

    2014-05-21

    Studying the interaction between neuronal cells and chiral molecules is fundamental for the design of novel biomaterials and drugs. Chirality influences all biological processes that involve intermolecular interaction. One common method used to study cellular interactions with different enantiomeric targets is the use of chiral surfaces. Based on previous studies that demonstrated the importance of cysteine in the nervous system, we studied the effect of L- and D-cysteine on single neuronal growth. L-Cysteine, which normally functions as a neuromodulator or a neuroprotective antioxidant, causes damage at elevated levels, which may occur post trauma. In this study, we grew adult neurons in culture enriched with L- and D-cysteine as free compounds or as self-assembled monolayers of chiral surfaces and examined the effect on the neuronal morphology and adhesion. Notably, we have found that exposure to the L-cysteine enantiomer inhibited, and even prevented, neuronal attachment more severely than exposure to the D-cysteine enantiomer. Atop the L-cysteine surfaces, neuronal growth was reduced and degenerated. Since the cysteine molecules were attached to the surface via the thiol groups, the neuronal membrane was exposed to the molecular chiral site. Thus, our results have demonstrated high neuronal chiral sensitivity, revealing chiral surfaces as indirect regulators of neuronal cells and providing a reference for studying chiral drugs.

  9. Therapeutic NOTCH3 cysteine correction in CADASIL using exon skipping: in vitro proof of concept

    NARCIS (Netherlands)

    Rutten, J.W.; Dauwerse, H.G.; Peters, D.J.; Goldfarb, A.; Venselaar, H.; Haffner, C.; Ommen, G.J. van; Aartsma-Rus, A.M.; Oberstein, S.A.

    2016-01-01

    Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, or CADASIL, is a hereditary cerebral small vessel disease caused by characteristic cysteine altering missense mutations in theNOTCH3gene.NOTCH3mutations in CADASIL result in an uneven number of cysteine

  10. Cysteine: a conditionally essential amino acid in low-birth-weight preterm infants?

    NARCIS (Netherlands)

    Riedijk, Maaike A.; van Beek, Ron H. T.; Voortman, Gardi; de Bie, Henrica M. A.; Dassel, Anne C. M.; van Goudoever, Johannes B.

    2007-01-01

    Cyst(e)ine can be synthesized de novo from methionine and serine and is, therefore, a nonessential amino acid in human adults. Several studies have suggested that cyst(e)ine might be a conditionally essential amino acid in preterm infants because of biochemical immaturity. No data are available on

  11. Resolution of oxidative stress by thioredoxin reductase: Cysteine versus selenocysteine

    Directory of Open Access Journals (Sweden)

    Brian Cunniff

    2014-01-01

    Full Text Available Thioredoxin reductase (TR catalyzes the reduction of thioredoxin (TRX, which in turn reduces mammalian typical 2-Cys peroxiredoxins (PRXs 1–4, thiol peroxidases implicated in redox homeostasis and cell signaling. Typical 2-Cys PRXs are inactivated by hyperoxidation of the peroxidatic cysteine to cysteine-sulfinic acid, and regenerated in a two-step process involving retro-reduction by sulfiredoxin (SRX and reduction by TRX. Here transient exposure to menadione and glucose oxidase was used to examine the dynamics of oxidative inactivation and reactivation of PRXs in mouse C10 cells expressing various isoforms of TR, including wild type cytoplasmic TR1 (Sec-TR1 and mitochondrial TR2 (Sec-TR2 that encode selenocysteine, as well as mutants of TR1 and TR2 in which the selenocysteine codon was changed to encode cysteine (Cys-TR1 or Cys-TR2. In C10 cells endogenous TR activity was insensitive to levels of hydrogen peroxide that hyperoxidize PRXs. Expression of Sec-TR1 increased TR activity, reduced the basal cytoplasmic redox state, and increased the rate of reduction of a redox-responsive cytoplasmic GFP probe (roGFP, but did not influence either the rate of inactivation or the rate of retro-reduction of PRXs. In comparison to roGFP, which was reduced within minutes once oxidants were removed reduction of 2-Cys PRXs occurred over many hours. Expression of wild type Sec-TR1 or Sec-TR2, but not Cys-TR1 or TR2, increased the rate of reduction of PRXs and improved cell survival after menadione exposure. These results indicate that expression levels of TR do not reduce the severity of initial oxidative insults, but rather govern the rate of reduction of cellular factors required for cell viability. Because Sec-TR is completely insensitive to cytotoxic levels of hydrogen peroxide, we suggest TR functions at the top of a redox pyramid that governs the oxidation state of peroxiredoxins and other protein factors, thereby dictating a hierarchy of phenotypic

  12. Cysteine 138 mutation in HIV-1 Nef from patients with delayed disease progression

    DEFF Research Database (Denmark)

    Tolstrup, Martin; Laursen, Alex Lund; Gerstoft, J.

    2006-01-01

    on the delayed disease status. However, the results demonstrate a high incidence of a single amino acid polymorphism (cysteine 138) in HIV-1 Nef. The allelic frequency of cysteine 138 between the delayed disease progression group and the progressor group was found to be statistically significant (P = 0.......0139). The phylogeny of isolates was investigated and the variants harbouring the cysteine 138 mutation clustered independently. CONCLUSION: The present study describes a viral genetic polymorphism related to AIDS disease progression. The polymorphism (cysteine 138) has previously been reported to confer decreased...... viral replication (Premkumar DR, et al. AIDS Res Hum Retroviruses 1996; 12(4): 337-45). A sequence database search for comparative mutations revealed a high frequency of cysteine 138 in patients with reported SP AIDS...

  13. Intramolecular synergistic effect of glutamic acid, cysteine and glycine against copper corrosion in hydrochloric acid solution

    International Nuclear Information System (INIS)

    Zhang Daquan; Xie Bin; Gao Lixin; Cai Qirui; Joo, Hyung Goun; Lee, Kang Yong

    2011-01-01

    The corrosion protection of copper by glutamic acid, cysteine, glycine and their derivative (glutathione) in 0.5 M hydrochloric acid solution has been studied by the electrochemical impedance spectroscopy and cyclic voltammetry. The inhibition efficiency of the organic inhibitors on copper corrosion increases in the order: glutathione > cysteine > cysteine + glutamic acid + glycine > glutamic acid > glycine. Maximum inhibition efficiency for cysteine reaches about 92.9% at 15 mM concentration level. The glutathione can give 96.4% inhibition efficiency at a concentration of 10 mM. The molecular structure parameters were obtained by PM3 (Parametric Method 3) semi-empirical calculation. The intramolecular synergistic effect of glutamic acid, cysteine and glycine moieties in glutathione is attributed to the lower energy of the lowest unoccupied molecular orbital (E LUMO ) level and to the excess hetero-atom adsorption centers and the bigger coverage on the copper surface.

  14. Mass spectrometric analysis of L-cysteine metabolism: physiological role and fate of L-cysteine in the enteric protozoan parasite Entamoeba histolytica.

    Science.gov (United States)

    Jeelani, Ghulam; Sato, Dan; Soga, Tomoyoshi; Watanabe, Haruo; Nozaki, Tomoyoshi

    2014-11-04

    L-cysteine is essential for virtually all living organisms, from bacteria to higher eukaryotes. Besides having a role in the synthesis of virtually all proteins and of taurine, cysteamine, glutathione, and other redox-regulating proteins, L-cysteine has important functions under anaerobic/microaerophilic conditions. In anaerobic or microaerophilic protozoan parasites, such as Entamoeba histolytica, L-cysteine has been implicated in growth, attachment, survival, and protection from oxidative stress. However, a specific role of this amino acid or related metabolic intermediates is not well understood. In this study, using stable-isotope-labeled L-cysteine and capillary electrophoresis-time of flight mass spectrometry, we investigated the metabolism of L-cysteine in E. histolytica. [U-(13)C3, (15)N]L-cysteine was rapidly metabolized into three unknown metabolites, besides L-cystine and L-alanine. These metabolites were identified as thiazolidine-4-carboxylic acid (T4C), 2-methyl thiazolidine-4-carboxylic acid (MT4C), and 2-ethyl-thiazolidine-4-carboxylic acid (ET4C), the condensation products of L-cysteine with aldehydes. We demonstrated that these 2-(R)-thiazolidine-4-carboxylic acids serve for storage of L-cysteine. Liberation of L-cysteine occurred when T4C was incubated with amebic lysates, suggesting enzymatic degradation of these L-cysteine derivatives. Furthermore, T4C and MT4C significantly enhanced trophozoite growth and reduced intracellular reactive oxygen species (ROS) levels when it was added to cultures, suggesting that 2-(R)-thiazolidine-4-carboxylic acids are involved in the defense against oxidative stress. Amebiasis is a human parasitic disease caused by the protozoan parasite Entamoeba histolytica. In this parasite, L-cysteine is the principal low-molecular-weight thiol and is assumed to play a significant role in supplying the amino acid during trophozoite invasion, particularly when the parasites move from the anaerobic intestinal lumen to highly

  15. A conserved glutamine plays a central role in LOV domain signal transmission and duration

    Science.gov (United States)

    Nash, Abigail I.; Ko, Wen-Huang; Harper, Shannon M.; Gardner, Kevin H.

    2009-01-01

    Light is a key stimulus for plant biological functions, several of which are controlled by light-activated kinases known as phototropins, a group of kinases that contain two light-sensing domains (LOV, Light-Oxygen-Voltage domains) and a C-terminal serine/threonine kinase domain. The second sensory domain, LOV2, plays a key role in regulating kinase enzymatic activity via the photochemical formation of a covalent adduct between a LOV2 cysteine residue and an internally-bound flavin mononucleotide (FMN) chromophore. Subsequent conformational changes in LOV2 lead to the unfolding of a peripheral Jα helix, and ultimately, phototropin kinase activation. To date, the mechanism coupling bond formation and helix dissociation has remained unclear. Previous studies found that a conserved glutamine residue (Q513 in the Avena sativa phototropin 1 LOV2 (AsLOV2) domain) switches its hydrogen-bonding pattern with FMN upon light stimulation. Located in the immediate vicinity of the FMN binding site, this Gln residue is provided by the Iβ strand that interacts with the Jα helix, suggesting a route for signal propagation from the core of the LOV domain to its peripheral Jα helix. To test whether Q513 plays a key role in tuning the photochemical and transduction properties of AsLOV2, we designed two point mutations, Q513L and Q513N, and monitored the effects on the chromophore and protein using a combination of UV-visible absorbance and circular dichroism spectroscopy, limited proteolysis, and solution NMR. The results show that these mutations significantly dampen the changes between the dark and lit state AsLOV2 structures, leaving the protein in a pseudo-dark state (Q513L) or a pseudo-lit state (Q513N) conformation. Further, both mutations changed the photochemical properties of this receptor, particularly the lifetime of the photoexcited signaling states. Together, these data establish that this residue plays a central role in both spectral tuning and signal propagation from

  16. Aspartic acid-promoted highly selective and sensitive colorimetric sensing of cysteine in rat brain.

    Science.gov (United States)

    Qian, Qin; Deng, Jingjing; Wang, Dalei; Yang, Lifen; Yu, Ping; Mao, Lanqun

    2012-11-06

    Direct selective determination of cysteine in the cerebral system is of great importance because of the crucial roles of cysteine in physiological and pathological processes. In this study, we report a sensitive and selective colorimetric assay for cysteine in the rat brain with gold nanoparticles (Au-NPs) as the signal readout. Initially, Au-NPs synthesized with citrate as the stabilizer are red in color and exhibit absorption at 520 nm. The addition of an aqueous solution (20 μL) of cysteine or aspartic acid alone to a 200 μL Au-NP dispersion causes no aggregation, while the addition of an aqueous solution of cysteine into a Au-NP dispersion containing aspartic acid (1.8 mM) causes the aggregation of Au-NPs and thus results in the color change of the colloid from wine red to blue. These changes are ascribed to the ion pair interaction between aspartic acid and cysteine on the interface between Au-NPs and solution. The concentration of cysteine can be visualized with the naked eye and determined by UV-vis spectroscopy. The signal output shows a linear relationship for cysteine within the concentration range from 0.166 to 1.67 μM with a detection limit of 100 nM. The assay demonstrated here is highly selective and is free from the interference of other natural amino acids and other thiol-containing species as well as the species commonly existing in the brain such as lactate, ascorbic acid, and glucose. The basal dialysate level of cysteine in the microdialysate from the striatum of adult male Sprague-Dawley rats is determined to be around 9.6 ± 2.1 μM. The method demonstrated here is facile but reliable and durable and is envisaged to be applicable to understanding the chemical essence involved in physiological and pathological events associated with cysteine.

  17. Development of 68Ga ethyl cysteinate dimer for PET studies

    International Nuclear Information System (INIS)

    Alireza Mirzaei; Jalilian, A.R.; Gholamali Shabani; Ashraf Fakhari; Mehdi Akhlaghi; Davood Beiki

    2016-01-01

    In this work development of 68 Ga-ethyl cysteinate dimer ( 68 Ga-ECD) a 68 Ga tracer for possible cerebral blood flow based on 99m Tc ECD homolog is reported. 68 Ga-ECD was prepared using generator-based 68 GaCl 3 and ECD at optimized conditions. Quality control, stability, partition co-efficient and the biodistribution of the tracer (by tissue counting and PET/CT in rats) was studied. Significant metabolism of the lipophilic tracer into water soluble metabolite(s) led to urinary excretion of the tracer, un-comparable to that of homologous 99m Tc-compound. Cardiac uptake of the complex suggests formation of a possible lipophil cationic complex and/or metabolite. (author)

  18. Unusual hydrogen bonding in L-cysteine hydrogen fluoride.

    Science.gov (United States)

    Minkov, V S; Ghazaryan, V V; Boldyreva, E V; Petrosyan, A M

    2015-08-01

    L-Cysteine hydrogen fluoride, or bis(L-cysteinium) difluoride-L-cysteine-hydrogen fluoride (1/1/1), 2C3H8NO2S(+)·2F(-)·C3H7NO2S·HF or L-Cys(+)(L-Cys···L-Cys(+))F(-)(F(-)...H-F), provides the first example of a structure with cations of the 'triglycine sulfate' type, i.e. A(+)(A···A(+)) (where A and A(+) are the zwitterionic and cationic states of an amino acid, respectively), without a doubly charged counter-ion. The salt crystallizes in the monoclinic system with the space group P2(1). The dimeric (L-Cys···L-Cys(+)) cation and the dimeric (F(-)···H-F) anion are formed via strong O-H···O or F-H···F hydrogen bonds, respectively, with very short O···O [2.4438 (19) Å] and F···F distances [2.2676 (17) Å]. The F···F distance is significantly shorter than in solid hydrogen fluoride. Additionally, there is another very short hydrogen bond, of O-H···F type, formed by a L-cysteinium cation and a fluoride ion. The corresponding O···F distance of 2.3412 (19) Å seems to be the shortest among O-H···F and F-H···O hydrogen bonds known to date. The single-crystal X-ray diffraction study was complemented by IR spectroscopy. Of special interest was the spectral region of vibrations related to the above-mentioned hydrogen bonds.

  19. Cysteine modified polyaniline films improve biocompatibility for two cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Yslas, Edith I., E-mail: eyslas@exa.unrc.edu.ar [Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Agencia Postal Nro3, X580BYA Río Cuarto (Argentina); Cavallo, Pablo; Acevedo, Diego F.; Barbero, César A. [Departamento de Química, Universidad Nacional de Río Cuarto, Agencia Postal Nro3, X580BYA Río Cuarto (Argentina); Rivarola, Viviana A. [Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Agencia Postal Nro3, X580BYA Río Cuarto (Argentina)

    2015-06-01

    This work focuses on one of the most exciting application areas of conjugated conducting polymers, which is cell culture and tissue engineering. To improve the biocompatibility of conducting polymers we present an easy method that involves the modification of the polymer backbone using L-cysteine. In this publication, we show the synthesis of polyaniline (PANI) films supported onto Polyethylene terephthalate (PET) films, and modified using cysteine (PANI-Cys) in order to generate a biocompatible substrate for cell culture. The PANI-Cys films are characterized by Fourier Transform infrared and UV–visible spectroscopy. The changes in the hydrophilicity of the polymer films after and before the modification were tested using contact angle measurements. After modification the contact angle changes from 86° ± 1 to 90° ± 1, suggesting a more hydrophylic surface. The adhesion properties of LM2 and HaCaT cell lines on the surface of PANI-Cys films in comparison with tissue culture plastic (TCP) are studied. The PANI-Cys film shows better biocompatibility than PANI film for both cell lines. The cell morphologies on the TCP and PANI-Cys film were examined by florescence and Atomic Force Microscopy (AFM). Microscopic observations show normal cellular behavior when PANI-Cys is used as a substrate of both cell lines (HaCaT and LM2) as when they are cultured on TCP. The ability of these PANI-Cys films to support cell attachment and growth indicates their potential use as biocompatible surfaces and in tissue engineering. - Highlights: • A new surface PANI-Cys was produced on films of polyethylene terephthalate. • The relationship between surface characteristics and biocompatibility is analyzed. • The PANI-Cys film presents good biocompatibility for two cell lines.

  20. Residual gas analysis

    International Nuclear Information System (INIS)

    Berecz, I.

    1982-01-01

    Determination of the residual gas composition in vacuum systems by a special mass spectrometric method was presented. The quadrupole mass spectrometer (QMS) and its application in thin film technology was discussed. Results, partial pressure versus time curves as well as the line spectra of the residual gases in case of the vaporization of a Ti-Pd-Au alloy were demonstrated together with the possible construction schemes of QMS residual gas analysers. (Sz.J.)

  1. Conservation agriculture effects on soil pore characteristics

    DEFF Research Database (Denmark)

    Munkholm, Lars Juhl; Abdollahi, Lotfollah

    ploughing to a depth of 20 cm (MP), harrowing to a depth of 8-10 cm (H) and direct drilling (D). Minimally disturbed core samples were taken at 4-8, 12-16 and 18-27 cm depths 11 years after experimental start. Water retention characteristics were measured for a range of matric potential ranging from -10......Conservation tillage in combination with crop rotation, residue management and cover crops are key components of conservation agriculture. A positive long-term effect of applying all components of conservation agriculture on soil structural quality is expected. However, there is a lack...... of quantitative knowledge to support this statement. This study examines the long-term effects of crop rotations, residue management and tillage on soil pore characteristics of two sandy loam soils in Denmark. Results are reported from a split plot field experiment rotation as main plot factor and tillage...

  2. Substrate Specificity of Cysteine Proteases Beyond the S2 Pocket: Mutagenesis and Molecular Dynamics Investigation of Fasciola hepatica Cathepsins L

    Directory of Open Access Journals (Sweden)

    Ileana Corvo

    2018-04-01

    Full Text Available Cysteine proteases are widespread in all life kingdoms, being central to diverse physiological processes based on a broad range of substrate specificity. Paralogous Fasciola hepatica cathepsin L proteases are essential to parasite invasion, tissue migration and reproduction. In spite of similarities in their overall sequence and structure, these enzymes often exhibit different substrate specificity. These preferences are principally determined by the amino acid composition of the active site's S2 subsite (pocket of the enzyme that interacts with the substrate P2 residue (Schetcher and Berger nomenclature. Although secreted FhCL1 accommodates aliphatic residues in the S2 pocket, FhCL2 is also efficient in cleaving proline in that position. To understand these differences, we engineered the FhCL1 S2 subsite at three amino acid positions to render it identical to that present in FhCL2. The substitutions did not produce the expected increment in proline accommodation in P2. Rather, they decreased the enzyme's catalytic efficiency toward synthetic peptides. Nonetheless, a change in the P3 specificity was associated with the mutation of Leu67 to Tyr, a hinge residue between the S2 and S3 subsites that contributes to the accommodation of Gly in S3. Molecular dynamic simulations highlighted changes in the spatial distribution and secondary structure of the S2 and S3 pockets of the mutant FhCL1 enzymes. The reduced affinity and catalytic efficiency of the mutant enzymes may be due to a narrowing of the active site cleft that hinders the accommodation of substrates. Because the variations in the enzymatic activity measured could not be exclusively allocated to those residues lining the active site, other more external positions might modulate enzyme conformation, and, therefore, catalytic activity.

  3. Knockout of the murine cysteine dioxygenase gene results in severe impairment in ability to synthesize taurine and an increased catabolism of cysteine to hydrogen sulfide

    Science.gov (United States)

    Ueki, Iori; Roman, Heather B.; Valli, Alessandro; Fieselmann, Krista; Lam, Jimmy; Peters, Rachel; Hirschberger, Lawrence L.

    2011-01-01

    Cysteine homeostasis is dependent on the regulation of cysteine dioxygenase (CDO) in response to changes in sulfur amino acid intake. CDO oxidizes cysteine to cysteinesulfinate, which is further metabolized to either taurine or to pyruvate plus sulfate. To gain insight into the physiological function of CDO and the consequence of a loss of CDO activity, mice carrying a null CDO allele (CDO+/− mice) were crossed to generate CDO−/−, CDO+/−, and CDO+/+ mice. CDO−/− mice exhibited postnatal mortality, growth deficit, and connective tissue pathology. CDO−/− mice had extremely low taurine levels and somewhat elevated cysteine levels, consistent with the lack of flux through CDO-dependent catabolic pathways. However, plasma sulfate levels were slightly higher in CDO−/− mice than in CDO+/− or CDO+/+ mice, and tissue levels of acid-labile sulfide were elevated, indicating an increase in cysteine catabolism by cysteine desulfhydration pathways. Null mice had lower hepatic cytochrome c oxidase levels, suggesting impaired electron transport capacity. Supplementation of mice with taurine improved survival of male pups but otherwise had little effect on the phenotype of the CDO−/− mice. H2S has been identified as an important gaseous signaling molecule as well as a toxicant, and pathology may be due to dysregulation of H2S production. Control of cysteine levels by regulation of CDO may be necessary to maintain low H2S/sulfane sulfur levels and facilitate the use of H2S as a signaling molecule. PMID:21693692

  4. The effect of various S-alkylating agents on the chromatographic behavior of cysteine-containing peptides in reversed-phase chromatography.

    Science.gov (United States)

    Jiang, Xuehui; Shamshurin, Dmitry; Spicer, Vic; Krokhin, Oleg V

    2013-02-01

    We investigate the influence of various alkylation chemistries on the reversed phase (RP) HPLC behavior of Cys-containing peptides under the most popular RP-HPLC conditions used in proteomics: C18 phases with trifluoroacetic acid (TFA) or formic acid (FA) as the ion pairing modifiers, and separation at pH 10. Akylating agents studied are iodoacetamide (IAM), iodoacetic acid (IAA), 4-vinylpyridine (4-VP), acrylamide (AA) and methyl methanethiosulfonate (MMTS). These were compared against the retention of identical peptides without alkylation, i.e. free cysteines. The intrinsic hydrophobicity values of the Cys residue under formic acid conditions for these modifications were found to increase in the following order: 4-VPalkylated Cys using TFA eluent. Switching to a basic condition dramatically decreases the retention of free cysteine and IAA-alkylated analytes due to the ionization of side-chains. The opposite effect is observed for 4-VP, which become neutral at basic pHs. The careful measurement of the hydrophobic contributions for these residues is vital to the development of accurate peptide retention prediction models; the incorporation of these modifications into our Sequence Specific Retention Calculator model is presented. Copyright © 2013. Published by Elsevier B.V.

  5. Antibody Binding Selectivity: Alternative Sets of Antigen Residues Entail High-Affinity Recognition.

    Directory of Open Access Journals (Sweden)

    Yves Nominé

    Full Text Available Understanding the relationship between protein sequence and molecular recognition selectivity remains a major challenge. The antibody fragment scFv1F4 recognizes with sub nM affinity a decapeptide (sequence 6TAMFQDPQER15 derived from the N-terminal end of human papilloma virus E6 oncoprotein. Using this decapeptide as antigen, we had previously shown that only the wild type amino-acid or conservative replacements were allowed at positions 9 to 12 and 15 of the peptide, indicating a strong binding selectivity. Nevertheless phenylalanine (F was equally well tolerated as the wild type glutamine (Q at position 13, while all other amino acids led to weaker scFv binding. The interfaces of complexes involving either Q or F are expected to diverge, due to the different physico-chemistry of these residues. This would imply that high-affinity binding can be achieved through distinct interfacial geometries. In order to investigate this point, we disrupted the scFv-peptide interface by modifying one or several peptide positions. We then analyzed the effect on binding of amino acid changes at the remaining positions, an altered susceptibility being indicative of an altered role in complex formation. The 23 starting variants analyzed contained replacements whose effects on scFv1F4 binding ranged from minor to drastic. A permutation analysis (effect of replacing each peptide position by all other amino acids except cysteine was carried out on the 23 variants using the PEPperCHIP® Platform technology. A comparison of their permutation patterns with that of the wild type peptide indicated that starting replacements at position 11, 12 or 13 modified the tolerance to amino-acid changes at the other two positions. The interdependence between the three positions was confirmed by SPR (Biacore® technology. Our data demonstrate that binding selectivity does not preclude the existence of alternative high-affinity recognition modes.

  6. The Evolution of the Scavenger Receptor Cysteine-Rich Domain of the Class A Scavenger Receptors

    Directory of Open Access Journals (Sweden)

    Nicholas eYap

    2015-07-01

    Full Text Available The class A Scavenger Receptor (cA-SR family is a group of five evolutionarily related innate immune receptors. The cA-SRs are known for their promiscuous ligand binding; as they have been shown to bind bacteria such as Streptococcus pneumoniae, and Escherichia coli, as well as different modified forms of low-density lipoprotein. Three of the five family members possess a Scavenger Receptor Cysteine Rich (SRCR domain while the remaining two receptors lack the domain. Previous work has suggested that the Macrophage Associated Receptor with COllagenous structure (MARCO shares a recent common ancestor with the non-SRCR-containing receptors; however the origin of the SRCR domain within the cA-SRs remains unknown. We hypothesize that the SRCR domains of the cA-SRs have a common origin that predates teleost fish. Using the newly available sequence data from sea lamprey and ghost shark genome projects, we have shown that MARCO shares a common ancestor with the SRCR-containing proteins. In addition, we explored the evolutionary relationships within the SRCR domain by reconstructing the ancestral SRCR domains of the cA-SRs. We identified a motif that is highly conserved between the cA-SR SRCR domains and the ancestral SRCR domain that consist of WGTVCDD. We also show that the GRAEVYY motif, a functionally important motif within MARCO, is poorly conserved in the other cA-SRs and in the reconstructed ancestral domain. Further, we identified three sites within MARCO’s SRCR domain which are under positive selection. Two of these sites lie adjacent to the conserved WGTVCDD motif, and may indicate a potential biological function for these sites. Together these findings indicate a common origin of the SRCR domain within the cA-SRs; however different selective pressures between the proteins may have caused MARCOs SRCR domain to evolve to contain different functional motifs when compared to the other SRCR-containing cA-SRs.

  7. Relative Stabilities of Conserved and Non-Conserved Structures in the OB-Fold Superfamily

    Directory of Open Access Journals (Sweden)

    Andrei T. Alexandrescu

    2009-05-01

    Full Text Available The OB-fold is a diverse structure superfamily based on a β-barrel motif that is often supplemented with additional non-conserved secondary structures. Previous deletion mutagenesis and NMR hydrogen exchange studies of three OB-fold proteins showed that the structural stabilities of sites within the conserved β-barrels were larger than sites in non-conserved segments. In this work we examined a database of 80 representative domain structures currently classified as OB-folds, to establish the basis of this effect. Residue-specific values were obtained for the number of Cα-Cα distance contacts, sequence hydrophobicities, crystallographic B-factors, and theoretical B-factors calculated from a Gaussian Network Model. All four parameters point to a larger average flexibility for the non-conserved structures compared to the conserved β-barrels. The theoretical B-factors and contact densities show the highest sensitivity.Our results suggest a model of protein structure evolution in which novel structural features develop at the periphery of conserved motifs. Core residues are more resistant to structural changes during evolution since their substitution would disrupt a larger number of interactions. Similar factors are likely to account for the differences in stability to unfolding between conserved and non-conserved structures.

  8. Facile and green synthesis of highly stable L-cysteine functionalized copper nanoparticles

    International Nuclear Information System (INIS)

    Kumar, Nikhil; Upadhyay, Lata Sheo Bachan

    2016-01-01

    Highlights: • A facile and eco-friendly method for the synthesis of L-cysteine functionalized copper nanoparticles is reported. • Synthesis of Highly stable L-cysteine functionalized copper nanoparticles (∼40 nm) was done in an aqueous medium. • FTIR analysis shows that L-cysteine bound to the nanoparticle surface via thiol group. - Abstract: A simple eco-friendly method for L-cysteine capped copper nanoparticles (CCNPs) synthesis in aqueous solution has been developed. Glucose and L-cysteine were used as reducing agent and capping/functionalizing agent, respectively. Different parameters such as capping agent concentration, pH, reaction temperature, and reducing agent concentration were optimized during the synthesis. The L-cysteine capped copper nanoparticle were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Particle size and zeta potential analyser, and high resolution transmission electron microscopy. Spherical shaped cysteine functionalized/capped copper nanoparticles with an average size of 40 nm were found to be highly stable at room temperature (RT) for a period of 1 month

  9. Facile and green synthesis of highly stable L-cysteine functionalized copper nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Nikhil, E-mail: nkumar.phd2011.bt@nitrr.ac.in; Upadhyay, Lata Sheo Bachan, E-mail: contactlataupadhyay@gmail.com

    2016-11-01

    Highlights: • A facile and eco-friendly method for the synthesis of L-cysteine functionalized copper nanoparticles is reported. • Synthesis of Highly stable L-cysteine functionalized copper nanoparticles (∼40 nm) was done in an aqueous medium. • FTIR analysis shows that L-cysteine bound to the nanoparticle surface via thiol group. - Abstract: A simple eco-friendly method for L-cysteine capped copper nanoparticles (CCNPs) synthesis in aqueous solution has been developed. Glucose and L-cysteine were used as reducing agent and capping/functionalizing agent, respectively. Different parameters such as capping agent concentration, pH, reaction temperature, and reducing agent concentration were optimized during the synthesis. The L-cysteine capped copper nanoparticle were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Particle size and zeta potential analyser, and high resolution transmission electron microscopy. Spherical shaped cysteine functionalized/capped copper nanoparticles with an average size of 40 nm were found to be highly stable at room temperature (RT) for a period of 1 month.

  10. The mechanism of cysteine detection in biological media by means of vanadium oxide nanoparticles

    International Nuclear Information System (INIS)

    Bezerra, A. G.; Barison, A.; Oliveira, V. S.; Foti, L.; Krieger, M. A.; Dhalia, R.; Viana, I. F. T.; Schreiner, W. H.

    2012-01-01

    We report on the interaction of vanadate nanoparticles, produced using the laser ablation in liquids synthesis, with cysteine in biological molecules. Cysteine is a very important amino acid present in most proteins, but also because cysteine and the tripeptide glutathione are the main antioxidant molecules in our body system. Detailed UV–Vis absorption spectra and dynamic light scattering measurements were done to investigate the detection of cysteine in large biological molecules. The intervalence band of the optical absorption spectra shows capability for quantitative cysteine sensing in the μM range in biological macromolecules. Tests included cytoplasmic repetitive antigen and flagellar repetitive antigen proteins of the Trypanosoma cruzi protozoa, as well as the capsid p24 proteins from Human Immunodeficiency Virus type 1 and type 2. Detailed NMR measurements for hydrogen, carbon, and vanadium nuclei show that cysteine in contact with the vanadate looses hydrogen of the sulphydryl side chain, while the vanadate is reduced. The subsequent detachment of two deprotonated molecules to form cystine and the slow return to the vanadate complete the oxidation–reduction cycle. Therefore, the vanadate acts as a charge exchanging catalyst on cysteine to form cystine. The NMR results also indicate that the nanoparticles are not formed by the common orthorhombic V 2 O 5 form.

  11. Acetaldehyde Removal from Indoor Air through Chemical Absorption Using L-Cysteine

    Directory of Open Access Journals (Sweden)

    Miyuki Noguchi

    2010-09-01

    Full Text Available The irreversible removal of acetaldehyde from indoor air via a chemical reaction with amino acids was investigated. To compare effectiveness, five types of amino acid (glycine, L-lysine, L-methionine, L-cysteine, and L-cystine were used as the reactants. First, acetaldehyde-laden air was introduced into aqueous solutions of each amino acid and the removal abilities were compared. Among the five amino acids, L-cysteine solution showed much higher removal efficiency, while the other amino acids solutions didn’t show any significant differences from the removal efficiency of water used as a control. Next, as a test of the removal abilities of acetaldehyde by semi-solid L-cysteine, a gel containing L-cysteine solution was put in a fluororesin bag filled with acetaldehyde gas, and the change of acetaldehyde concentration was measured. The L-cysteine-containing gel removed 80% of the acetaldehyde in the air within 24 hours. The removal ability likely depended on the unique reaction whereby acetaldehyde and L-cysteine rapidly produce 2-methylthiazolidine-4-carboxylic acid. These results suggested that the reaction between acetaldehyde and L-cysteine has possibilities for irreversibly removing toxic acetaldehyde from indoor air.

  12. The mechanism of cysteine detection in biological media by means of vanadium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, A. G. [Universidade Tecnologica Federal do Parana, Departamento Academico de Fisica (Brazil); Barison, A. [Universidade Federal do Parana, Departamento de Quimica (Brazil); Oliveira, V. S. [Universidade Federal do Parana, Departamento de Fisica (Brazil); Foti, L.; Krieger, M. A. [Fundacao Oswaldo Cruz, Instituto de Biologia Molecular do Parana (Brazil); Dhalia, R.; Viana, I. F. T. [Fundacao Oswaldo Cruz, Centro de Pesquisas Aggeu Magalhaes (Brazil); Schreiner, W. H., E-mail: wido@fisica.ufpr.br [Universidade Federal do Parana, Departamento de Fisica (Brazil)

    2012-09-15

    We report on the interaction of vanadate nanoparticles, produced using the laser ablation in liquids synthesis, with cysteine in biological molecules. Cysteine is a very important amino acid present in most proteins, but also because cysteine and the tripeptide glutathione are the main antioxidant molecules in our body system. Detailed UV-Vis absorption spectra and dynamic light scattering measurements were done to investigate the detection of cysteine in large biological molecules. The intervalence band of the optical absorption spectra shows capability for quantitative cysteine sensing in the {mu}M range in biological macromolecules. Tests included cytoplasmic repetitive antigen and flagellar repetitive antigen proteins of the Trypanosoma cruzi protozoa, as well as the capsid p24 proteins from Human Immunodeficiency Virus type 1 and type 2. Detailed NMR measurements for hydrogen, carbon, and vanadium nuclei show that cysteine in contact with the vanadate looses hydrogen of the sulphydryl side chain, while the vanadate is reduced. The subsequent detachment of two deprotonated molecules to form cystine and the slow return to the vanadate complete the oxidation-reduction cycle. Therefore, the vanadate acts as a charge exchanging catalyst on cysteine to form cystine. The NMR results also indicate that the nanoparticles are not formed by the common orthorhombic V{sub 2}O{sub 5} form.

  13. Identification of Key Residues for Enzymatic Carboxylate Reduction

    Directory of Open Access Journals (Sweden)

    Holly Stolterfoht

    2018-02-01

    Full Text Available Carboxylate reductases (CARs, E.C. 1.2.1.30 generate aldehydes from their corresponding carboxylic acid with high selectivity. Little is known about the structure of CARs and their catalytically important amino acid residues. The identification of key residues for carboxylate reduction provides a starting point to gain deeper understanding of enzymatic carboxylate reduction. A multiple sequence alignment of CARs with confirmed activity recently identified in our lab and from the literature revealed a fingerprint of conserved amino acids. We studied the function of conserved residues by multiple sequence alignments and mutational replacements of these residues. In this study, single-site alanine variants of Neurospora crassa CAR were investigated to determine the contribution of conserved residues to the function, expressability or stability of the enzyme. The effect of amino acid replacements was investigated by analyzing enzymatic activity of the variants in vivo and in vitro. Supported by molecular modeling, we interpreted that five of these residues are essential for catalytic activity, or substrate and co-substrate binding. We identified amino acid residues having significant impact on CAR activity. Replacement of His 237, Glu 433, Ser 595, Tyr 844, and Lys 848 by Ala abolish CAR activity, indicating their key role in acid reduction. These results may assist in the functional annotation of CAR coding genes in genomic databases. While some other conserved residues decreased activity or had no significant impact, four residues increased the specific activity of NcCAR variants when replaced by alanine. Finally, we showed that NcCAR wild-type and mutants efficiently reduce aliphatic acids.

  14. Transcriptome Analysis of Maize Immature Embryos Reveals the Roles of Cysteine in Improving Agrobacterium Infection Efficiency

    Science.gov (United States)

    Liu, Yan; Zhang, Zhiqiang; Fu, Junjie; Wang, Guoying; Wang, Jianhua; Liu, Yunjun

    2017-01-01

    Maize Agrobacterium-mediated transformation efficiency has been greatly improved in recent years. Antioxidants, such as, cysteine, can significantly improve maize transformation frequency through improving the Agrobacterium infection efficiency. However, the mechanism underlying the transformation improvement after cysteine exposure has not been elucidated. In this study, we showed that the addition of cysteine to the co-cultivation medium significantly increased the Agrobacterium infection efficiency of hybrid HiII and inbred line Z31 maize embryos. Reactive oxygen species contents were higher in embryos treated with cysteine than that without cysteine. We further investigated the mechanism behind cysteine-related infection efficiency increase using transcriptome analysis. The results showed that the cysteine treatment up-regulated 939 genes and down-regulated 549 genes in both Z31 and HiII. Additionally, more differentially expressed genes were found in HiII embryos than those in Z31 embryos, suggesting that HiII was more sensitive to the cysteine treatment than Z31. GO analysis showed that the up-regulated genes were mainly involved in the oxidation reduction process. The up-regulation of these genes could help maize embryos to cope with the oxidative stress stimulated by Agrobacterium infection. The down-regulated genes were mainly involved in the cell wall and membrane metabolism, such as, aquaporin and expansin genes. Decreased expression of these cell wall integrity genes could loosen the cell wall, thereby improving the entry of Agrobacterium into plant cells. This study offers insight into the role of cysteine in improving Agrobacterium-mediated transformation of maize immature embryos. PMID:29089955

  15. Negative modulation of the GABAA ρ1 receptor function by l-cysteine.

    Science.gov (United States)

    Beltrán González, Andrea N; Vicentini, Florencia; Calvo, Daniel J

    2018-01-01

    l-Cysteine is an endogenous sulfur-containing amino acid with multiple and varied roles in the central nervous system, including neuroprotection and the maintenance of the redox balance. However, it was also suggested as an excitotoxic agent implicated in the pathogenesis of neurological disorders such as Parkinson's and Alzheimer's disease. l-Cysteine can modulate the activity of ionic channels, including voltage-gated calcium channels and glutamatergic NMDA receptors, whereas its effects on GABAergic neurotransmission had not been studied before. In the present work, we analyzed the effects of l-cysteine on responses mediated by homomeric GABA A ρ1 receptors, which are known for mediating tonic γ-aminobutyric acid (GABA) responses in retinal neurons. GABA A ρ1 receptors were expressed in Xenopus laevis oocytes and GABA-evoked chloride currents recorded by two-electrode voltage-clamp in the presence or absence of l-cysteine. l-Cysteine antagonized GABA A ρ1 receptor-mediated responses; inhibition was dose-dependent, reversible, voltage independent, and susceptible to GABA concentration. Concentration-response curves for GABA were shifted to the right in the presence of l-cysteine without a substantial change in the maximal response. l-Cysteine inhibition was insensitive to chemical protection of the sulfhydryl groups of the ρ1 subunits by the irreversible alkylating agent N-ethyl maleimide. Our results suggest that redox modulation is not involved during l-cysteine actions and that l-cysteine might be acting as a competitive antagonist of the GABA A ρ1 receptors. © 2017 International Society for Neurochemistry.

  16. Structures of pseudechetoxin and pseudecin, two snake-venom cysteine-rich secretory proteins that target cyclic nucleotide-gated ion channels: implications for movement of the C-terminal cysteine-rich domain

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Nobuhiro [Department of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan); Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); Yamazaki, Yasuo [Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588 (Japan); Brown, R. Lane [Neurological Science Institute, Oregon Health and Science University, Beaverton, Oregon 97006 (United States); Fujimoto, Zui [Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); Morita, Takashi, E-mail: tmorita@my-pharm.ac.jp [Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588 (Japan); Mizuno, Hiroshi, E-mail: tmorita@my-pharm.ac.jp [Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602 (Japan); VALWAY Technology Center, NEC Soft Ltd, Koto-ku, Tokyo 136-8627 (Japan); Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology, Central 6, Tsukuba, Ibaraki 305-8566 (Japan); Department of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan)

    2008-10-01

    The structures of pseudechetoxin and pseudecin suggest that both proteins bind to cyclic nucleotide-gated ion channels in a manner in which the concave surface occludes the pore entrance. Cyclic nucleotide-gated (CNG) ion channels play pivotal roles in sensory transduction by retinal photoreceptors and olfactory neurons. The elapid snake toxins pseudechetoxin (PsTx) and pseudecin (Pdc) are the only known protein blockers of CNG channels. These toxins belong to a cysteine-rich secretory protein (CRISP) family containing an N-terminal pathogenesis-related proteins of group 1 (PR-1) domain and a C-terminal cysteine-rich domain (CRD). PsTx and Pdc are highly homologous proteins, but their blocking affinities on CNG channels are different: PsTx blocks both the olfactory and retinal channels with ∼15–30-fold higher affinity than Pdc. To gain further insights into their structure and function, the crystal structures of PsTx, Pdc and Zn{sup 2+}-bound Pdc were determined. The structures revealed that most of the amino-acid-residue differences between PsTx and Pdc are located around the concave surface formed between the PR-1 domain and the CRD, suggesting that the concave surface is functionally important for CNG-channel binding and inhibition. A structural comparison in the presence and absence of Zn{sup 2+} ion demonstrated that the concave surface can open and close owing to movement of the CRD upon Zn{sup 2+} binding. The data suggest that PsTx and Pdc occlude the pore entrance and that the dynamic motion of the concave surface facilitates interaction with the CNG channels.

  17. Structures of pseudechetoxin and pseudecin, two snake-venom cysteine-rich secretory proteins that target cyclic nucleotide-gated ion channels: implications for movement of the C-terminal cysteine-rich domain

    International Nuclear Information System (INIS)

    Suzuki, Nobuhiro; Yamazaki, Yasuo; Brown, R. Lane; Fujimoto, Zui; Morita, Takashi; Mizuno, Hiroshi

    2008-01-01

    The structures of pseudechetoxin and pseudecin suggest that both proteins bind to cyclic nucleotide-gated ion channels in a manner in which the concave surface occludes the pore entrance. Cyclic nucleotide-gated (CNG) ion channels play pivotal roles in sensory transduction by retinal photoreceptors and olfactory neurons. The elapid snake toxins pseudechetoxin (PsTx) and pseudecin (Pdc) are the only known protein blockers of CNG channels. These toxins belong to a cysteine-rich secretory protein (CRISP) family containing an N-terminal pathogenesis-related proteins of group 1 (PR-1) domain and a C-terminal cysteine-rich domain (CRD). PsTx and Pdc are highly homologous proteins, but their blocking affinities on CNG channels are different: PsTx blocks both the olfactory and retinal channels with ∼15–30-fold higher affinity than Pdc. To gain further insights into their structure and function, the crystal structures of PsTx, Pdc and Zn 2+ -bound Pdc were determined. The structures revealed that most of the amino-acid-residue differences between PsTx and Pdc are located around the concave surface formed between the PR-1 domain and the CRD, suggesting that the concave surface is functionally important for CNG-channel binding and inhibition. A structural comparison in the presence and absence of Zn 2+ ion demonstrated that the concave surface can open and close owing to movement of the CRD upon Zn 2+ binding. The data suggest that PsTx and Pdc occlude the pore entrance and that the dynamic motion of the concave surface facilitates interaction with the CNG channels

  18. Sequencing and characterization of asclepain f: the first cysteine peptidase cDNA cloned and expressed from Asclepias fruticosa latex.

    Science.gov (United States)

    Trejo, Sebastián A; López, Laura M I; Caffini, Néstor O; Natalucci, Claudia L; Canals, Francesc; Avilés, Francesc X

    2009-07-01

    Asclepain f is a papain-like protease previously isolated and characterized from latex of Asclepias fruticosa. This enzyme is a member of the C1 family of cysteine proteases that are synthesized as preproenzymes. The enzyme belongs to the alpha + beta class of proteins, with two disulfide bridges (Cys22-Cys63 and Cys56-Cys95) in the alpha domain, and another one (Cys150-Cys201) in the beta domain, as was determined by molecular modeling. A full-length 1,152 bp cDNA was cloned by RT-RACE-PCR from latex mRNA. The sequence was predicted as an open reading frame of 340 amino acid residues, of which 16 residues belong to the signal peptide, 113 to the propeptide and 211 to the mature enzyme. The full-length cDNA was ligated to pPICZalpha vector and expressed in Pichia pastoris. Recombinant asclepain f showed endopeptidase activity on pGlu-Phe-Leu-p-nitroanilide and was identified by PMF-MALDI-TOF MS. Asclepain f is the first peptidase cloned and expressed from mRNA isolated from plant latex, confirming the presence of the preprocysteine peptidase in the latex.

  19. Preparation, crystallization and X-ray diffraction analysis to 1.5 Å resolution of rat cysteine dioxygenase, a mononuclear iron enzyme responsible for cysteine thiol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Chad R. [Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853-8001 (United States); Hao, Quan [MacCHESS at the Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853-8001 (United States); Stipanuk, Martha H., E-mail: mhs6@cornell.edu [Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853-8001 (United States)

    2005-11-01

    Recombinant rat cysteine dioxygenase (CDO) has been expressed, purified and crystallized and X-ray diffraction data have been collected to 1.5 Å resolution. Cysteine dioxygenase (CDO; EC 1.13.11.20) is an ∼23 kDa non-heme iron metalloenzyme that is responsible for the oxidation of cysteine by O{sub 2}, yielding cysteinesulfinate. CDO catalyzes the first step in the conversion of cysteine to taurine, as well as the first step in the catabolism of cysteine to pyruvate plus sulfate. Recombinant rat CDO was heterologously expressed, purified and crystallized. The protein was expressed as a fusion protein bearing a polyhistidine tag to facilitate purification, a thioredoxin tag to improve solubility and a factor Xa cleavage site to permit removal of the entire N-terminus, leaving only the 200 amino acids inherent to the native protein. A multi-step purification scheme was used to achieve >95% purity of CDO. The optimal CDO crystals diffracted to 1.5 Å resolution and belonged to space group P4{sub 3}2{sub 1}2 or P4{sub 1}2{sub 1}2, with unit-cell parameters a = b = 57.55, c = 123.06 Å, α = β = γ = 90°. CDO shows little homology to any other proteins; therefore, the structure of the enzyme will be determined by ab initio phasing using a selenomethionyl derivative.

  20. Dynamics of postirradiation intracellular cysteine and aspartic proteinases profiles in proliferating and nonproliferating mammalian cells

    International Nuclear Information System (INIS)

    Korbelik, M.; Osmak, M.; Suhar, A.; Turk, V.; Skrk, J.

    1990-01-01

    Dynamics of postirradiation intracellular cysteine and aspartic proteinases profiles were examined in proliferating and nonproliferating Chinese hamster fibroblasts (V 79). The results show that there are significant alterations in cysteine and aspartic intracellular proteinases activity already in the early postirradiation period, which are different in proliferating and nonproliferating cells. Irradiation of the cells examined to low doses and up to 15 Gy induced an increase in cysteine proteinases activity in the early postexposure period, while at higher irradiation doses applied, the activity of these proteinases was decreased. These observations suggest that intracellular proteinases are actively participating in process involving recovery from radiation injury or cell killing. (orig.) [de

  1. Adsorption Dynamics and Self-Assembled L-cysteine on Au(100)

    DEFF Research Database (Denmark)

    Engelbrekt, Christian; Nazmutdinov, Renat R.; Yan, Jiawei

    As the only amino acid with a functional thiol group, L - cysteine offers a strong perspective both for binding to gold and other metals, and for gentle immobilization of biomolecules. Binding to single - crystal, atomically planar surfaces offers the additional perspective that bound L - cysteine...... can be structurally mapped at the single - molecule level . In this work, we have followed the adsorption of L - cysteine on single - crystal Au(100) by measuring the electrode potential dynamics during the adsorption process. In situ STM revealed the structure of the self - assembled ordered layers...

  2. E.S.R. studies of mechanisms of radiation protection effect by cysteine and cystine

    International Nuclear Information System (INIS)

    Xue-Peng, L.; Tie-Cheng, T.; Nian-Yun, L.

    1981-01-01

    By means of E.S.R. the repair mechanism of radiation induced spin transfer from dTMP to cysteine in binary system dTMP-cysteine has been confirmed. Furthermore, a new marked radiation protection effect, exerted by cysteine or cystine on thymine irradiated and observed at low temperature, has been detected. Another sort of fast protection mechanism, including electron transfer and excitation transfer, has been proposed, based on recent advances of primary radiation process of pyrimidine bases and analysed by molecular orbital theory. This fast radiation protection mechanism provides the possibility to utilize electrophilic sulfhydryl protectors for realizing excellent protection effect. (author)

  3. Interaction of cysteine and copper ions on the surface of iron: EIS, polarization and XPS study

    International Nuclear Information System (INIS)

    El-Deab, Mohamed S.

    2011-01-01

    Highlights: → The current study demonstrates a comprehensive study for Cysteine + Cu(II) ions as an efficient inhibitor as demonstrated by EIS, XPS and potentiodynamic polarization measurements, in addition to traditional weight loss measurements. → The novelty of the current work originates from the combined use of an eco-friendly compound (i.e., cysteine) with a minute amount of copper ions (in the micro molar range) as a corrosion inhibitor for low carbon steel in acidic medium. To this end, cysteine shows only moderate inhibition ca. 60% for iron which jumps up to more than 95% in the presence of micro molar range of Cu(II) ions. → Cysteine-Cu(II) blends are found superior to benzotriazole (BTAH)-Cu(II) blends in terms of their long-term stability in addition to the avoidance of the use of the well-reported highly toxic BTAH. - Abstract: This study addresses the enhancing effect of copper ions on the inhibition efficiency (IE) of cysteine (an eco-friendly compound) against the corrosion of iron in 0.5 M sulphuric acid. Electrochemical impedance spectroscopy (EIS) data revealed a significant increase in the polarization resistance (R p ) of the iron/solution interface in the presence of cysteine and Cu(II) ions instead of cysteine alone. That is, IE of 95% is obtained in the presence of 5 mM cysteine and 25 μM Cu(II) ions, compared to 66% in absence of Cu(II) ions. Moreover, electrochemical polarization measurements indicate that cysteine and Cu(II) ions blends act as mixed-type inhibitors for the corrosion of iron. The formation of Cu(I)-cysteinate complex and/or cysteine SAM at Cu atop the iron surface (as evident from X-ray photoelectron spectroscopy (XPS)) blocks the underlying iron surface and imparts a pronounced protection against its corrosion. IE of cysteine-Cu(II) blend remains effectively unchanged with immersion time indicating its high stability in the used acidic medium.

  4. Oral Administration of (S)-Allyl-l-Cysteine and Aged Garlic Extract to Rats: Determination of Metabolites and Their Pharmacokinetics.

    Science.gov (United States)

    Park, Taehoon; Oh, Ju-Hee; Lee, Joo Hyun; Park, Sang Cheol; Jang, Young Pyo; Lee, Young-Joo

    2017-11-01

    ( S )-Allyl-l-cysteine is the major bioactive compound in garlic. ( S )-Allyl-l-cysteine is metabolized to ( S )-allyl-l-cysteine sulfoxide, N -acetyl-( S )-allyl-l-cysteine, and N -acetyl-( S )-allyl-l-cysteine sulfoxide after oral administration. An accurate LC-MS/MS method was developed and validated for the simultaneous quantification of ( S )-allyl-l-cysteine and its metabolites in rat plasma, and the feasibility of using it in pharmacokinetic studies was tested. The analytes were quantified by multiple reaction monitoring using an atmospheric pressure ionization mass spectrometer. Because significant quantitative interference was observed between ( S )-allyl-l-cysteine and N -acetyl-( S )-allyl-l-cysteine as a result of the decomposition of N -acetyl-( S )-allyl-l-cysteine at the detector source, chromatographic separation was required to discriminate ( S )-allyl-l-cysteine and its metabolites on a reversed-phase C 18 analytical column with a gradient mobile phase consisting of 0.1% formic acid and acetonitrile. The calibration curves of ( S )-allyl-l-cysteine, ( S )-allyl-l-cysteine sulfoxide, N -acetyl-( S )-allyl-l-cysteine, and N -acetyl-( S )-allyl-l-cysteine sulfoxide were linear over each concentration range, and the lower limits of quantification were 0.1 µg/mL [( S )-allyl-l-cysteine and N -acetyl-( S )-allyl-l-cysteine] and 0.25 µg/mL [( S )-allyl-l-cysteine sulfoxide and N -acetyl-( S )-allyl-l-cysteine sulfoxide]. Acceptable intraday and inter-day precisions and accuracies were obtained at three concentration levels. The method satisfied the regulatory requirements for matrix effects, recovery, and stability. The validated LC-MS/MS method was successfully used to determine the concentration of ( S )-allyl-l-cysteine and its metabolites in rat plasma samples after the administration of ( S )-allyl-l-cysteine or aged garlic extract. Georg Thieme Verlag KG Stuttgart · New York.

  5. Characterization of the secreted cathepsin B cysteine proteases family of the carcinogenic liver fluke Clonorchis sinensis.

    Science.gov (United States)

    Chen, Wenjun; Wang, Xiaoyun; Lv, Xiaoli; Tian, Yanli; Xu, Yanquan; Mao, Qiang; Shang, Mei; Li, Xuerong; Huang, Yan; Yu, Xinbing

    2014-09-01

    Clonorchis sinensis excretory/secretory products (ESP) have gained high attentions because of their potential to be vaccine candidates and drug targets in C. sinensis prevention. In this study, we extensively profiled the characteristics of four C. sinensis cathepsin B cysteine proteases (CsCB1, CsCB2, CsCB3, and CsCB4). Bioinformatics analysis showed all CsCBs contained signal peptides at the N-terminal. Functional domains and residues were found in CsCB sequences. We expressed four CsCBs and profiled immune responses followed by vaccine trials. Recombinant CsCBs could induce high IgG titers, indicating high immunogenicity of CsCB family. Additionally, ELISA results showed that both IgG1 and IgG2a levels apparently increased post-immunization with all four CsCBs, showing that combined Th1/Th2 immune responses were triggered by CsCB family. Both Real-time polymerase chain reaction (RT-PCR) and Western blotting confirmed that four CsCBs have distinct expression patterns in C. sinensis life stages. More importantly, we validated our hypothesis that CsCBs were C. sinensis excretory/secretory products. CsCBs could be recognized by C. sinensis-infected sera throughout the infection period, indicating that secreted CsCBs are immune triggers during C. sinensis infection. The protective effect was assessed by comparing the worm burden and egg per gram (EPG) between CsCB group and control group, showing that worm burden (P sinensis excretory/secretory products that may regulate host immune responses.

  6. Distinct Mechanism of Cysteine Oxidation-Dependent Activation and Cold Sensitization of Human Transient Receptor Potential Ankyrin 1 Channel by High and Low Oxaliplatin

    Directory of Open Access Journals (Sweden)

    Takahito Miyake

    2017-11-01

    Full Text Available Oxaliplatin, a third-generation platinum-based chemotherapeutic agent, displays unique acute peripheral neuropathy triggered or enhanced by cold, and accumulating evidence suggests that transient receptor potential ankyrin 1 (TRPA1 is responsible. TRPA1 is activated by oxaliplatin via a glutathione-sensitive mechanism. However, oxaliplatin interrupts hydroxylation of a proline residue located in the N-terminal region of TRPA1 via inhibition of prolyl hydroxylase (PHD, which causes sensitization of TRPA1 to reactive oxygen species (ROS. Furthermore, PHD inhibition endows cold-insensitive human TRPA1 (hTRPA1 with ROS-dependent cold sensitivity. Since cysteine oxidation and proline hydroxylation regulate its activity, their association with oxaliplatin-induced TRPA1 activation and acquirement of cold sensitivity were investigated in the present study. A high concentration of oxaliplatin (1 mM induced outward-rectifier whole-cell currents and increased the intracellular Ca2+ concentration in hTRPA1-expressing HEK293 cells, but did not increase the probability of hTRPA1 channel opening in the inside-out configuration. Oxaliplatin also induced the rapid generation of hydrogen peroxide, and the resultant Ca2+ influx was prevented in the presence of glutathione and in cysteine-mutated hTRPA1 (Cys641Ser-expressing cells, whereas proline-mutated hTRPA1 (Pro394Ala-expressing cells showed similar whole-cell currents and Ca2+ influx. By contrast, a lower concentration of oxaliplatin (100 μM did not increase the intracellular Ca2+ concentration but did confer cold sensitivity on hTRPA1-expressing cells, and this was inhibited by PHD2 co-overexpression. Cold sensitivity was abolished by the mitochondria-targeting ROS scavenger mitoTEMPO and was minimal in cysteine-mutated hTRPA1 (Cys641Ser or Cys665Ser-expressing cells. Thus, high oxaliplatin evokes ROS-mediated cysteine oxidation-dependent hTRPA1 activation independent of PHD activity, while a lower

  7. Density functional theory and quantum mechanics/molecular mechanics study of cysteine protease inhibition by nitrile-based inhibitors.

    Directory of Open Access Journals (Sweden)

    Sam P De Visser

    2013-12-01

    Full Text Available Cysteine protease enzymes are important for human physiology and catalyze key protein degradation pathways. These enzymes react via a nucleophilic reaction mechanism that involves a cysteine residue and the proton of a proximal histidine. Particularly efficient inhibitors of these enzymes are nitrile-based, however, the details of the catalytic reaction mechanism currently are poorly understood. To gain further insight into the inhibition of these molecules, we have performed a combined density functional theory and quantum mechanics/molecular mechanics study on the reaction of a nitrile-based inhibitor with the enzyme active site amino acids. We show here that small perturbations to the inhibitor structure can have dramatic effects on the catalysis and inhibition processes. Thus, we investigated a range of inhibitor templates and show that specific structural changes reduce the inhibitory efficiency by several orders of magnitude. Moreover, as the reaction takes place on a polar surface, we find strong differences between the DFT and QM/MM calculated energetics. In particular, the DFT model led to dramatic distortions from the starting structure and the convergence to a structure that would not fit the enzyme active site. In the subsequent QM/MM study we investigated the use of mechanical versus electronic embedding on the kinetics, thermodynamics and geometries along the reaction mechanism. We find minor effects on the kinetics of the reaction but large geometric and thermodynamics differences as a result of inclusion of electronic embedding corrections. The work here highlights the importance of model choice in the investigation of this biochemical reaction mechanism.

  8. Handling of Solid Residues

    International Nuclear Information System (INIS)

    Medina Bermudez, Clara Ines

    1999-01-01

    The topic of solid residues is specifically of great interest and concern for the authorities, institutions and community that identify in them a true threat against the human health and the atmosphere in the related with the aesthetic deterioration of the urban centers and of the natural landscape; in the proliferation of vectorial transmitters of illnesses and the effect on the biodiversity. Inside the wide spectrum of topics that they keep relationship with the environmental protection, the inadequate handling of solid residues and residues dangerous squatter an important line in the definition of political and practical environmentally sustainable. The industrial development and the population's growth have originated a continuous increase in the production of solid residues; of equal it forms, their composition day after day is more heterogeneous. The base for the good handling includes the appropriate intervention of the different stages of an integral administration of residues, which include the separation in the source, the gathering, the handling, the use, treatment, final disposition and the institutional organization of the administration. The topic of the dangerous residues generates more expectation. These residues understand from those of pathogen type that are generated in the establishments of health that of hospital attention, until those of combustible, inflammable type, explosive, radio-active, volatile, corrosive, reagent or toxic, associated to numerous industrial processes, common in our countries in development

  9. Compatibility in the Ustilago maydis-maize interaction requires inhibition of host cysteine proteases by the fungal effector Pit2.

    Directory of Open Access Journals (Sweden)

    André N Mueller

    2013-02-01

    Full Text Available The basidiomycete Ustilago maydis causes smut disease in maize, with large plant tumors being formed as the most prominent disease symptoms. During all steps of infection, U. maydis depends on a biotrophic interaction, which requires an efficient suppression of plant immunity. In a previous study, we identified the secreted effector protein Pit2, which is essential for maintenance of biotrophy and induction of tumors. Deletion mutants for pit2 successfully penetrate host cells but elicit various defense responses, which stops further fungal proliferation. We now show that Pit2 functions as an inhibitor of a set of apoplastic maize cysteine proteases, whose activity is directly linked with salicylic-acid-associated plant defenses. Consequently, protease inhibition by Pit2 is required for U. maydis virulence. Sequence comparisons with Pit2 orthologs from related smut fungi identified a conserved sequence motif. Mutation of this sequence caused loss of Pit2 function. Consequently, expression of the mutated protein in U. maydis could not restore virulence of the pit2 deletion mutant, indicating that the protease inhibition by Pit2 is essential for fungal virulence. Moreover, synthetic peptides of the conserved sequence motif showed full activity as protease inhibitor, which identifies this domain as a new, minimal protease inhibitor domain in plant-pathogenic fungi.

  10. Plasma Total Cysteine and Cardiovascular Risk Burden: Action and Interaction

    Directory of Open Access Journals (Sweden)

    Benedetta De Chiara

    2012-01-01

    Full Text Available We hypothesized that redox analysis could provide sensitive markers of the oxidative pathway associated to the presence of an increasing number of cardiovascular risk factors (RFs, independently of type. We classified 304 subjects without cardiovascular disease into 4 groups according to the total number of RFs (smoking, hypertension, hypercholesterolaemia, hyperhomocysteinaemia, diabetes, obesity, and their combination. Oxidative stress was evaluated by measuring plasma total and reduced homocysteine, cysteine (Cys, glutathione, cysteinylglycine, blood reduced glutathione, and malondialdehyde. Twenty-seven percent of subjects were in group 0 RF, 26% in 1 RF, 31% in 2 RF, and 16% in ≥3 RF. By multivariable ordinal regression analysis, plasma total Cys was associated to a higher number of RF (OR = 1.068; 95% CI = 1.027–1.110, =0.002. Total RF burden is associated with increased total Cys levels. These findings support a prooxidant effect of Cys in conjunction with RF burden, and shed light on the pathophysiologic role of redox state unbalance in preclinical atherosclerosis.

  11. Peptidomic Identification of Cysteine-Rich Peptides from Plants.

    Science.gov (United States)

    Hemu, Xinya; Serra, Aida; Darwis, Dina A; Cornvik, Tobias; Sze, Siu Kwan; Tam, James P

    2018-01-01

    Plant cysteine-rich peptides (CRPs) constitute a majority of plant-derived peptides with high molecular diversity. This protocol describes a rapid and efficient peptidomic approach to identify a whole spectrum of CRPs in a plant extract and decipher their molecular diversity and bioprocessing mechanism. Cyclotides from C. ternatea are used as the model CRPs to demonstrate our methodology. Cyclotides exist naturally in both cyclic and linear forms, although the linear forms (acyclotide) are generally present at much lower concentrations. Both cyclotides and acyclotides require linearization of their backbone prior to fragmentation and sequencing. A novel and practical three-step chemoenzymatic treatment was developed to linearize and distinguish both forms: (1) N-terminal acetylation that pre-labels the acyclotides; (2) conversion of Cys into pseudo-Lys through aziridine-mediated S-alkylation to reduce disulfide bonds and to increase the net charge of peptides; and (3) opening of cyclic backbones by the novel asparaginyl endopeptidase butelase 2 that cleaves at the native bioprocessing site. The treated peptides are subsequently analyzed by liquid chromatography coupled to mass spectrometry using electron transfer dissociation fragmentation and sequences are identified by matching the MS/MS spectra directly with the transcriptomic database.

  12. Differential Expression of Cysteine Dioxygenase 1 in Complex Karyotype Liposarcomas

    Directory of Open Access Journals (Sweden)

    Mohammed Shaker

    2014-01-01

    Full Text Available Altered cysteine dioxygenase 1 (CDO1 gene expression has been observed in several cancers but has not yet been investigated in liposarcomas. The aim of this study was to evaluate CDO1 expression in a cohort of liposarcomas and to determine its association with clinicopathological features. Existing microarray data indicated variable CDO1 expression in liposarcoma subtypes. CDO1 mRNA from a larger cohort of liposarcomas was quantified by real time-PCR, and CDO1 protein expression was determined by immunohistochemistry (IHC in more than 300 tumor specimens. Well-differentiated liposarcomas (WDLSs had significantly higher CDO1 gene expression and protein levels than dedifferentiated liposarcomas (DDLSs ( P < 0.001. Location of the tumor was not predictive of the expression level of CDO1 mRNA in any histological subtype of liposarcoma. Recurrent tumors did not show any difference in CDO1 expression when compared to primary tumors. CDO1 expression was upregulated as human mesenchymal stem cells (hMSCs undergo differentiation into mature adipocytes. Our results suggest that CDO1 is a marker of liposarcoma progression and adipogenic differentiation.

  13. A spinach O-acetylserine(thiollyase homologue, SoCSaseLP, suppresses cysteine biosynthesis catalysed by other enzyme isoforms

    Directory of Open Access Journals (Sweden)

    Miki Noda

    2016-06-01

    Full Text Available An enzyme, O-acetylserine(thiollyase (OASTL, also known as O-acetylserine sulfhydrylase or cysteine synthase (CSase, catalyses the incorporation of sulfide into O-acetylserine and produces cysteine. We previously identified a cDNA encoding an OASTL-like protein from Spinacia oleracea, (SoCSaseLP, but a recombinant SoCSaseLP produced in Escherichia coli did not show OASTL activity. The exon-intron structure of the SoCSaseLP gene shared conserved structures with other spinach OASTL genes. The SoCSaseLP and a Beta vulgaris homologue protein, KMT13462, comprise a unique clade in the phylogenetic tree of the OASTL family. Interestingly, when the SoCSaseLP gene was expressed in tobacco plants, total OASTL activity in tobacco leaves was reduced. This reduction in total OASTL activity was most likely caused by interference by SoCSaseLP with cytosolic OASTL. To investigate the possible interaction of SoCSaseLP with a spinach cytosolic OASTL isoform SoCSaseA, a pull-down assay was carried out. The recombinant glutathione S-transferase (GST-SoCSaseLP fusion protein was expressed in E. coli together with the histidine-tagged SoCSaseA protein, and the protein extract was subjected to glutathione affinity chromatography. The histidine-tagged SoCSaseA was co-purified with the GST-SoCSaseLP fusion protein, indicating the binding of SoCSaseLP to SoCSaseA. Consistent with this interaction, the OASTL activity of the co-purified SoCSaseA was reduced compared with the activity of SoCSaseA that was purified on its own. These results strongly suggest that SoCSaseLP negatively regulates the activity of other cytosolic OASTL family members by direct interaction.

  14. A turn-on fluorescent sensor for the discrimination of cystein from homocystein and glutathione.

    Science.gov (United States)

    Niu, Li-Ya; Guan, Ying-Shi; Chen, Yu-Zhe; Wu, Li-Zhu; Tung, Chen-Ho; Yang, Qing-Zheng

    2013-02-14

    We report a turn-on fluorescent sensor based on nitrothiophenolate boron dipyrromethene (BODIPY) derivatives for the discrimination of cystein (Cys) from homocystein (Hcy) and glutathione (GSH). The sensor was applied for detection of Cys in living cells.

  15. Enzymatic synthesis of S-phenyl-L-cysteine from keratin hydrolysis industries wastewater with tryptophan synthase.

    Science.gov (United States)

    Xu, Lisheng; Wang, Zhiyuan; Mao, Pingting; Liu, Junzhong; Zhang, Hongjuan; Liu, Qian; Jiao, Qing-Cai

    2013-04-01

    An economical method for production of S-phenyl-L-cysteine from keratin acid hydrolysis wastewater (KHW) containing L-serine was developed by recombinant tryptophan synthase. This study provides us with an alternative KHW utilization strategy to synthesize S-phenyl-L-cysteine. Tryptophan synthase could efficiently convert L-serine contained in KHW to S-phenyl-L-cysteine at pH 9.0, 40°C and Trion X-100 of 0.02%. In a scale up study, L-serine conversion rate reach 97.1% with a final S-phenyl-L-cysteine concentration of 38.6 g l(-1). Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Facile and green synthesis of highly stable L-cysteine functionalized copper nanoparticles

    Science.gov (United States)

    Kumar, Nikhil; Upadhyay, Lata Sheo Bachan

    2016-11-01

    A simple eco-friendly method for L-cysteine capped copper nanoparticles (CCNPs) synthesis in aqueous solution has been developed. Glucose and L-cysteine were used as reducing agent and capping/functionalizing agent, respectively. Different parameters such as capping agent concentration, pH, reaction temperature, and reducing agent concentration were optimized during the synthesis. The L-cysteine capped copper nanoparticle were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Particle size and zeta potential analyser, and high resolution transmission electron microscopy. Spherical shaped cysteine functionalized/capped copper nanoparticles with an average size of 40 nm were found to be highly stable at room temperature (RT) for a period of 1 month

  17. Chiral supramolecular gold-cysteine nanoparticles: Chiroptical and nonlinear optical properties

    Directory of Open Access Journals (Sweden)

    Isabelle Russier-Antoine

    2016-10-01

    Full Text Available Cysteine is a sulfur-containing amino acid that easily coordinates to soft metal ions and grafts to noble metal surfaces. We report a simple synthetic approach for the production of chiral gold-cysteine polymeric nanoparticles soluble in water. Conjugation of cysteine with gold in a polymeric way, leading to ~50 nm diameter nanoparticles, resulted in the generation of new characteristic circular dichroism (CD signals in the region of 250–400 nm, whereas no CD signal changes were found with cysteine alone. We also investigate their nonlinear optical properties after two-photon absorption. Two-photon emission spectra and first hyper-polarizabilities, as obtained by the hyper-Rayleigh scattering technique, of these particles are presented.

  18. Development of a cysteine-deprived and C-terminally truncated GLP-1 receptor

    DEFF Research Database (Denmark)

    Underwood, Christina Rye; Knudsen, Lotte Bjerre; Garibay, Patrick W.

    2013-01-01

    The glucagon-like peptide-1 receptor (GLP-1R) belongs to family B of the G-protein coupled receptors (GPCRs), and has become a promising target for the treatment of type 2 diabetes. Here we describe the development and characterization of a fully functional cysteine-deprived and C......-terminally truncated GLP-1R. Single cysteines were initially substituted with alanine, and functionally redundant cysteines were subsequently changed simultaneously. Our results indicate that Cys174, Cys226, Cys296 and Cys403 are important for the GLP-1-mediated response, whereas Cys236, Cys329, Cys341, Cys347, Cys438...... that the membrane proximal part of the C-terminal is involved in receptor expression at the cell surface. The results show that seven cysteines and more than half of the C-terminal tail can be removed from GLP-1R without compromising GLP-1 binding or function....

  19. Controllable synthesis of TiO2 nanomaterials by assisting with l-cysteine and ethylenediamine

    KAUST Repository

    Tao, Yugui

    2013-11-21

    This paper reports a facile l-cysteine-assisted solvothermal synthesis of TiO2 nanomaterials using ethylenediamine (En) and distilled water as solvent. The influence of reaction time, temperature, l-cysteine and solvent was initially investigated. Results demonstrated the reaction temperature, l-cysteine and En significantly imposed impact on the phase and morphology of the particles. Amorphous nanosheets, mixed-crystal nanorods and pure anatase nanoparticles were controllably synthesized by varying reaction temperature. The formation of the amorphous nanosheets and mixed-crystal nanorods were directly affected by the presence of l-cysteine and En. And the presence of En distinctly affected the crystal phase of the products, which was rarely mentioned in other studies. Moreover, the photocatalytic activities of three typical samples were excellent. The possible formation mechanism of the sample was also discussed. © 2013 Springer Science+Business Media New York.

  20. Controllable synthesis of TiO2 nanomaterials by assisting with l-cysteine and ethylenediamine

    KAUST Repository

    Tao, Yugui; Cao, Ning; Pan, Jun; Sun, Yichen; Jin, Cheng; Song, Yang

    2013-01-01

    This paper reports a facile l-cysteine-assisted solvothermal synthesis of TiO2 nanomaterials using ethylenediamine (En) and distilled water as solvent. The influence of reaction time, temperature, l-cysteine and solvent was initially investigated. Results demonstrated the reaction temperature, l-cysteine and En significantly imposed impact on the phase and morphology of the particles. Amorphous nanosheets, mixed-crystal nanorods and pure anatase nanoparticles were controllably synthesized by varying reaction temperature. The formation of the amorphous nanosheets and mixed-crystal nanorods were directly affected by the presence of l-cysteine and En. And the presence of En distinctly affected the crystal phase of the products, which was rarely mentioned in other studies. Moreover, the photocatalytic activities of three typical samples were excellent. The possible formation mechanism of the sample was also discussed. © 2013 Springer Science+Business Media New York.

  1. 7-cysteine-pyrrole conjugate: A new potential DNA reactive metabolite of pyrrolizidine alkaloids.

    Science.gov (United States)

    He, Xiaobo; Xia, Qingsu; Ma, Liang; Fu, Peter P

    2016-01-01

    Pyrrolizidine alkaloids (PAs) require metabolic activation to exert cytotoxicity, genotoxicity, and tumorigenicity. We previously reported that (±)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived DNA adducts are responsible for PA-induced liver tumor formation in rats. In this study, we determined that metabolism of riddelliine and monocrotaline by human or rat liver microsomes produced 7-cysteine-DHP and DHP. The metabolism of 7-glutathionyl-DHP by human and rat liver microsomes also generated 7-cysteine-DHP. Further, reaction of 7-cysteine-DHP with calf thymus DNA in aqueous solution yielded the described DHP-derived DNA adducts. This study represents the first report that 7-cysteine-DHP is a new PA metabolite that can lead to DNA adduct formation.

  2. High-performance liquid chromatography-fluorescence assay of pyruvic acid to determine cysteine conjugate beta-lyase activity : application to S-1,2-dichlorovinyl-L-cysteine and S-2-benzothiazolyl-L-cysteine

    NARCIS (Netherlands)

    Stijntjes, G.J.; te Koppele, J.M.; Vermeulen, N P

    1992-01-01

    An HPLC-fluorescence assay has been developed for the determination of the activity of rat renal cytosolic cysteine conjugate beta-lyase. The method is based on isocratic HPLC separation and fluorescence detection of pyruvic acid, derivatized with o-phenylenediamine (OPD), and is shown to be rapid,

  3. Conservation potential of agricultural water conservation subsidies

    Science.gov (United States)

    Huffaker, Ray

    2008-07-01

    A current policy subsidizes farmers to invest in improved on-farm irrigation efficiency, expecting water to be conserved off farm. Contrary to expectation, water has been increasingly depleted in some regions after such improvements. This paper investigates the policy's failure to conserve water consistently by (1) formulating an economic model of irrigated crop production to determine a profit-maximizing irrigator's range of responses to a subsidy and (2) embedding these responses into hypothetical streamflow diagrams to ascertain their potential to conserve water under various hydrologic regimes. Testable hypotheses are developed to predict the conservation potential of a subsidy in real-world application.

  4. Mechanism of S-oxygenation by a cysteine dioxygenase model complex

    OpenAIRE

    Kumar, Devesh; Sastry, G. Narahari; Goldberg, David P.; de Visser, Sam P.

    2011-01-01

    In this work we present the first computational study on a biomimetic cysteine dioxygenase model complex, [FeII(LN3S)]+ where LN3S is a tetradentate ligand with a bis(imino)pyridyl scaffold and a pendant arylthiolate group. The reaction mechanism of sulfur dioxygenation with O2 was examined by density functional theory (DFT) methods, and compared to results obtained for cysteine dioxygenase. The reaction proceeds via multistate reactivity patterns on competing singlet, triplet and quintet spi...

  5. [Protective Effect of S-isopentenyl-L-cysteine against DNA Damage in Irradiated Mice].

    Science.gov (United States)

    Zheng, Qi-sheng; Yu, Guang-yun; He, Xin; Jiang, Ming; Chu, Xiao-fei; Zhao, Shu-yi; Fan, Sai-jun; Liu, Pei-xun

    2015-10-01

    To evaluate the protective effect of S-isopentenyl-L-cysteine,a new cysteine derivative,on DNA damage induced by radiation by using acute radiation injury animal models. Forty ICR mice were randomly divided into five groups:the control group,1.0Gy gamma irradiation group,1.0Gy gamma irradiation combined with S-isopentenyl-L-cysteine group,7.2Gy gamma irradiation group,and 7.2Gy gamma irradiation combined with S-isopentenyl-L-cysteine group,with 8 mice in each group.The comet assay and bone marrow polychromatic micronucleus experiments were performed to evaluate the double-strand DNA breaks in ICR mice exposed to 1.0 and 7.2Gy gamma-ray, respectively. The tail DNA percentage,tail length,tail moment,and olive tail moment of peripheral blood lymphocytes in 7.2Gy gamma irradiation group were significantly higher than that of the control group (PL-cysteine group was significantly less than that of 7.2Gy gamma irradiation group (PL-cysteine before irradiation,the micronucleus rate of ICR mice exposed to 1.0 and 7.2Gy gamma-ray decreased from (39.5000 ± 3.3141)‰ to (28.1667±4.1345)‰ (P=0.033) and from (76.5000 ± 4.6242)‰ to (22.8333 ± 3.6553)‰(P=0.000),respectively. The bone marrow polychromatic micronucleus experiment indicated that the value of polychromatic erythrocyte (PCE)/normochromatic erythrocyte(NCE) of ICR mice exposed to 1.0 and 7.2Gy gamma-ray was less than the control group(PL-cysteine before irradiation was significantly higher than the corresponding groups (PL-cysteine has a good protective effect against DNA damage induced by radiation.

  6. Transamination of cysteine-sulfinic acid by extracts of oat leaves

    International Nuclear Information System (INIS)

    Perez-Milan, H.; Schuack, J.; Fromageot, P.

    1960-01-01

    An aqueous extract of oat leaves catalyses a transamination between cysteine-sulfinic acid and α-ketoglutaric acid. Under the conditions utilized pyruvic acid is not an acceptor of the amino group. Neither cysteic nor aspartic acid are a substrate for the transaminase of cysteine-sulfinic acid. Reprint of a paper published in Biochimica et Biophysica Acta, Vol. 36, 1959, p. 73-83 [fr

  7. Study of the histochemical detection of cysteine desulfhydrase in the vitellin sac of birds (1961)

    International Nuclear Information System (INIS)

    Chapeville, F.; Khau Van Kien, L.

    1961-01-01

    We have developed a method for the histochemical detection of cysteine desulfhydrase in the vitellin sac of the chicken embryo. The enzyme is localized in the presence of a lead salt by lead sulphide formed in situ from hydrogen sulphide liberated from the cysteine. The micrographs obtained are histological and show the presence of the enzyme in the different types of endoderm cell. (authors) [fr

  8. Correlation of secreted protein acidic and rich in cysteine with diabetic nephropathy

    OpenAIRE

    Li, Lei; Song, Hai-Yan; Liu, Kai; An, Meng-Meng

    2015-01-01

    To detect the serum concentrations of secreted protein acidic and rich in cysteine (SPARC) in patients with diabetic nephropathy and SPARC mRNA and protein expressions in renal tissue of db/db mice (C57BL/KsJ, diabetic nephropathy mice), thus preliminary exploration on the role of secreted protein acidic riches in cysteine in the development of diabetic nephropathy were carried out. Serum SPARC levels in normal subjects, patients with type 2 diabetes mellitus (without diabetic nephropathy), c...

  9. Preparation and application of L-cysteine-doped Keggin polyoxometalate microtubes

    International Nuclear Information System (INIS)

    Shen Yan; Peng Jun; Zhang Huanqiu; Meng Cuili; Zhang Fang

    2012-01-01

    L-cysteine-doped tungstosilicate (Lcys-SiW 12 ) microtubes are prepared, and the amount of L-cysteine doped in the microtubes can be tuned to some extent. The as-prepared Lcys-SiW 12 microtubes are sensitive to ammonia gas exhibited through the distinct color change of the microtubes from light purple to dark blue after exposing to ammonia gas. A possible mechanism of the coloration is that the adsorbed ammonia molecules increase the basicity of the Lcys-SiW 12 microtubes and promote the redox reaction between L-cysteine and polyoxometalate. This is a pH-dependent solid–solid redox reaction, which is triggered by proton capture agent. The Lcys-SiW 12 microtubes show application in chemical sensors for alkaline gases. - Graphical abstract: The Lcys-SiW 12 microtubes were formed during transformation of the monolacunary Keggin-type [α-SiW 11 O 39 ] 8− to the saturated Keggin-type [α-SiW 12 O 40 ] 4− , meanwhile L-cysteine molecules were doped during the growth of the microtubes. Highlights: ► L-cysteine-doped polyoxometalate microtubes are prepared. ► Amount of L-cysteine doped in the microtubes can be tuned to some extent. ► Lcys-SiW 12 microtubes can be applied as a sensor for detecting alkaline gases. ► This is a proton capture agent-triggered solid–solid redox reaction.

  10. Structural influence in the interaction of cysteine with five coordinated copper complexes: Theoretical and experimental studies

    Science.gov (United States)

    Huerta-Aguilar, Carlos Alberto; Thangarasu, Pandiyan; Mora, Jesús Gracia

    2018-04-01

    Copper complexes of N,N,N‧,N‧-tetrakis(pyridyl-2-ylmethyl)-1,2-diaminoethane (L1) and N,N,N‧,N‧-tetrakis(pyridyl-2-ylmethyl)-1,3-diaminopropane (L2) prepared were characterized completely by different analytical methods. The X-structure of the complexes shows that Cu(II) presents in trigonal bi-pyramidal (TBP) geometry, consisting with the electronic spectra where two visible bands corresponding to five coordinated structure were observed. Thus TD-DFT was used to analyze the orbital contribution to the electronic transitions for the visible bands. Furthermore, the interaction of cysteine with the complexes was spectrally studied, and the results were explained through DFT analysis, observing that the geometrical parameters and oxidation state of metal ions play a vital role in the binding of cysteine with copper ion. It appears that the TBP structure is being changed into octahedral geometry during the addition of cysteine to the complexes as two bands (from complex) is turned to a broad band in visible region, signifying the occupation of cysteine molecule at sixth position of octahedral geometry. In the molecular orbital analysis, the existence of a strong overlapping of HOMOs (from cysteine) with LUMOs of Cu ion was observed. The total energy of the systems calculated by DFT shows that cysteine binds favorably with copper (I) than that with Cu(II).

  11. Electrochemical behavior of cysteine at a CuGeO3 nanowires modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Dong Yongping; Pei Lizhai; Chu Xiangfeng; Zhang Wangbing; Zhang Qianfeng

    2010-01-01

    A CuGeO 3 nanowire modified glassy carbon electrode was fabricated and characterized by scanning electron microscopy. The results of electrochemical impedance spectroscopy reveal that electron transfer through nanowire film is facile compared with that of bare glassy carbon electrode. The modified electrode exhibited a novel electrocatalytic behavior to the electrochemical reactions of L-cysteine in neutral solution, which was not reported previously. Two pairs of semi-reversible electrochemical peaks were observed and assigned to the processes of oxidation/reduction and adsorption/desorption of cysteine at the modified electrode, respectively. The electrochemical response of cysteine is poor in alkaline condition and is enhanced greatly in acidic solution, suggesting that hydrogen ions participate in the electrochemical oxidation process of cysteine. The intensities of two anodic peaks varied linearly with the concentration of cysteine in the range of 1 x 10 -6 to 1 x 10 -3 mol L -1 , which make it possible to sensitive detection of cysteine with the CuGeO 3 nanowire modified electrode. Furthermore, the modified electrode exhibited good reproducibility and stability.

  12. Electrochemical behaviour of dopamine at covalent modified glassy carbon electrode with l-cysteine: preliminary results

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Martínez-Huitle

    2009-01-01

    Full Text Available The surface of glassy carbon (GC electrode has been modified by oxidation of L-cysteine. The covalent modified GC electrode with L-Cysteine has been studied, according the supporting electrolyte used. Favourable interactions between the L-cysteine film and DA enhance the current response compared to that at the Nafion GC and bare GC electrodes, achieving better performances than those other electrodes. This behaviour was as result of the adsorption of the cysteine layer film, compact and uniform formation; depending on L-cysteine solution (phosphate buffer or chloridric acid supporting electrolyte used for modifying GC surface. In cyclic voltammetric measurements, modified electrodes can successfully separate the oxidation/reduction DA peaks in different buffer solutions, but an evident dependence in the response was obtained as function of pH and modified electrode. The modified electrode prepared with L-cysteine/HCl solution was used to obtain the calibration curve and it exhibited a stable and sensitive response to DA. The results are described and discussed in the light of the existing literature.

  13. Depletion of circulating cyst(e)ine by oral and intravenous mesna.

    Science.gov (United States)

    Stofer-Vogel, B.; Cerny, T.; Küpfer, A.; Junker, E.; Lauterburg, B. H.

    1993-01-01

    The sulfhydryl status of normal and tumour cells is critically important in determining their susceptibility to various cytostatic agents. As a sulfhydryl compound, mesna (sodium 2-mercaptoethane-sulfonate) which is used in large doses to prevent haemorrhagic cystitis associated with certain chemotherapeutic regimens might derange cellular thiol homeostasis. In order to investigate the effects of mesna on the concentrations of thiols in plasma, cysteine, glutathione and their disulfides were measured by HPLC following the oral and intravenous administration of mesna to healthy volunteers. After 7.3 mmol mesna i.v. free cysteine rose from 8.2 (95% CI 7.0-9.4) nmol ml-1 to 53.6 (47.4-59.8) nmol ml-1 at 5 min, most likely due to reduction of circulating cystine by the sulfhydryl drug. This initial rise was followed by a marked decrease of total cyst(e)ine in plasma from 276 (215-337) nmol ml-1 to a nadir of 102 (89-115) nmol ml-1 between 30-120 min after infusion, most likely due to an increased uptake of cysteine into cells and an increased urinary excretion of cyst(e)ine. Qualitatively similar changes were seen after oral mesna. The present data indicate that mesna depletes circulating cyst(e)ine and may thereby markedly alter the sulfhydryl status of cells in vivo although the drug itself is not taken up by most cells. PMID:8353049

  14. [Construction of RNA-containing virus-like nanoparticles expression vector with cysteine residues on surface and fluorescent decoration].

    Science.gov (United States)

    Cheng, Yang-Jian; Liang, Ji-Xuan; Li, Qing-Ge

    2005-08-01

    Site-directed mutagenesis was performed at the codon 15 of the MS2 bacteriophage coat protein gene,which had been cloned to the virus-like particles expression vector containing non-self RNA fragment. The produced expression vector,termed pARSC, was transformed to E. coli DH5alpha. The positive clones were selected and proliferated. The harvested cells were treated with sonication and the supernatant was then subjected to linear sucrose density gradients centrifugation (15% to 60%) at 32000 r/min for 4 h at 4 degrees C. The virus-like particles, VLP-Cy, were collected at 35% sucrose density. The particles were examined by transmission electron microscopy and the spherical viral particles of approximately 27 nm in diameter were found. The thiolated VLP-Cy was then chemically modified with fluorescein -5'-maleimide. The covalent fluorescent labeling was confirmed by absorption analysis, SDS-PAGE and MALDI-TOF mass spectroscopy. This is the first report of preparation of RNA-containing natural fluorescent nanoparticles. The study highlight the versatility of MS2 bacteriophage capsids as building blocks for functional nanomaterials construction for a variety of application purposes.

  15. Characterization of Hospital Residuals

    International Nuclear Information System (INIS)

    Blanco Meza, A.; Bonilla Jimenez, S.

    1997-01-01

    The main objective of this investigation is the characterization of the solid residuals. A description of the handling of the liquid and gassy waste generated in hospitals is also given, identifying the source where they originate. To achieve the proposed objective the work was divided in three stages: The first one was the planning and the coordination with each hospital center, in this way, to determine the schedule of gathering of the waste can be possible. In the second stage a fieldwork was made; it consisted in gathering the quantitative and qualitative information of the general state of the handling of residuals. In the third and last stage, the information previously obtained was organized to express the results as the production rate per day by bed, generation of solid residuals for sampled services, type of solid residuals and density of the same ones. With the obtained results, approaches are settled down to either determine design parameters for final disposition whether for incineration, trituration, sanitary filler or recycling of some materials, and storage politics of the solid residuals that allow to determine the gathering frequency. The study concludes that it is necessary to improve the conditions of the residuals handling in some aspects, to provide the cleaning personnel of the equipment for gathering disposition and of security, minimum to carry out this work efficiently, and to maintain a control of all the dangerous waste, like sharp or polluted materials. In this way, an appreciable reduction is guaranteed in the impact on the atmosphere. (Author) [es

  16. L-Cysteine halogenides: A new family of salts with an L-cysteine⋯L-cysteinium dimeric cation

    Science.gov (United States)

    Ghazaryan, V. V.; Minkov, V. S.; Boldyreva, E. V.; Petrosyan, A. M.

    2016-10-01

    Two L-cysteinium-halogenides with (L-cysteine···L-cysteinium) dimeric cations have been obtained, (L-Cys⋯L-Cys+)·Cl-, and (L-Cys⋯L-Cys+)·Br-. Both salts crystallize in monoclinic space group P21. Although these salts have the same dimeric cations and isotypical halogen anions, crystal packing is different. The main difference between the two salts rests in the conformation of (L-Cys⋯L-Cys+) dimeric cation, which also differs from that of the dimeric cation in the previously reported compound L-Cys+(L-Cys⋯L-Cys+)·F-·(F-⋯HF). The dimeric cation is formed by a very short O-H⋯O hydrogen bond with d(O···O) of 2.449(2) Å and 2.435(11) Å in the chloride and bromide, respectively. In addition to crystal structure analysis, Infrared and Raman spectra have been registered and discussed with a particular focus on intermolecular interactions. The L-Cys+·Br-·H2O salt with a simple L-cysteinium cation was also obtained and the crystal structure solved. It resembles its chloride analogue, L-Cys+·Cl-·H2O.

  17. [Effects of redox state of disulfide bonds on the intrinsic fluorescence and denaturation of Trx-fused gibberellin-induced cysteine-rich protein from Gymnadnia conopsea].

    Science.gov (United States)

    Zhang, Teng; Feng, Juan; Li, Yang; Chen, Rui; Tang, Li-Xia; Pang, Xiao-Feng; Ren, Zheng-Long

    2010-02-01

    In the present paper, thioredoxin-fused gibberellin-induced cysteine-rich protein from Gymnadnia conopsea, desigated as Trx-GcGASA and expressed prokaryotically, was purified and identified by using Ni(2+) -NTA affinity chromatography column and SDS-PAGE, and then its intrinsic fluorescence was investigated in the absence and presence of dithiothreitol (DTT), oxidized glutathione (GSSG), peroxide and guanidine hydrochloride (GdnHCl) by means of steady-state fluorescence spectroscopic methods. It was found that (1) at the neutral pH Trx-GcGASA had maximum fluorescence emission at 305 nm following excitation at different wavelengths varying from 250 to 280 nm, which was ascribed to the fluorescence emission from tyrosine residues. (2) The reduction of disulphide bonds lead to the changes in the relative fluorescence intensity between tyrosine and tryptophan residues from 0.7 to 1.8. (3) Both Tyr and Trp residues underwent 12%-21% decrease in fluorescence intensity with the addition of 0.5 mmol x L(-1) GSSG or 5 mmol x L(-1) peroxide. The latter was roughly consistent with the antioxidative activity reported in vivo. (4) No matter whether 1 mmol x L(-1) DTT was absent or present, the fusion protein could not be fully unfolded with lambda(max) Trx-GcGASA experienced GdnHCl-induced denaturation process, and the unfolding equilibrium curve could be well fitted by using two-state model, giving the Gibbs free energy change (deltaG) of 3.7 kJ x mol(-1). However, it was not the case for reduced Trx-GcGASA protein. The aforementioned experimental results will not only provide some guides to investigate the effects of fusion partner Trx on the unfolding thermodynamics, kinetics and refolding process of Trx-GcGASA, but also will be useful for further studies on the strucuture of GA-induced cysteine-rich protein with the help of spectroscopic methods.

  18. Transcription factor DecR (YbaO) controls detoxification of L-cysteine in Escherichia coli.

    Science.gov (United States)

    Shimada, Tomohiro; Tanaka, Kan; Ishihama, Akira

    2016-09-01

    YbaO is an uncharacterized AsnC-family transcription factor of Escherichia coli. In both Salmonella enterica and Pantoea ananatis, YbaO homologues were identified to regulate the adjacent gene encoding cysteine desulfhydrase for detoxification of cysteine. Using the genomic SELEX (systematic evolution of ligands by exponential enrichment) screening system, we identified the yhaOM operon, located far from the ybaO gene on the E. coli genome, as a single regulatory target of YbaO. In both gel shift assay in vitro and reporter and Northern blot assays in vivo, YbaO was found to regulate the yhaOM promoter. The growth of mutants lacking either ybaO or its targets yhaOM was delayed in the presence of cysteine, indicating involvement of these genes in cysteine detoxification. In the major pathway of cysteine degradation, hydrogen sulfide is produced in wild-type E. coli, but its production was not observed in each of the ybaO, yhaO and yhaM mutants. The yhaOM promoter was activated in the presence of cysteine, implying the role of cysteine in activation of YbaO. Taken together, we propose that YbaO is the cysteine-sensing transcriptional activator of the yhaOM operon, which is involved in the detoxification of cysteine. We then propose the naming of ybaO as decR (regulator of detoxification of cysteine).

  19. Water conservation in semiarid dryland agriculture

    International Nuclear Information System (INIS)

    Willis, W.O.

    1980-01-01

    Factors affecting water conservation in semiarid dryland regions are discussed. Because precipitation is the only source of water for plant growth in most semiarid regions, a good understanding of precipitation patterns (quantity, distribution, and their probable frequency) is needed for each dryland area. The various dryland practices, e.g. tillage, cultivars, residue management, fertility, erosion control, and grazing, must be considered as integral parts of an entire system to develop best management practices and to gain most efficient water conservation for food and fiber production. (author)

  20. Identification of functionally important amino acid residues in the mitochondria targeting sequence of Hepatitis B virus X protein

    International Nuclear Information System (INIS)

    Li, Sai Kam; Ho, Sai Fan; Tsui, Kwok Wing; Fung, Kwok Pui; Waye, M.Y. Mary

    2008-01-01

    Chronic hepatitis B virus (HBV) infection has been strongly associated with hepatocellular carcinoma (HCC) and the X protein (HBx) is thought to mediate the cellular changes associated with carcinogenesis. Recently, isolation of the hepatitis B virus integrants from HCC tissue by others have established the fact that the X gene is often truncated at its C-terminus. Expression of the GFP fusion proteins of HBx and its truncation mutants with a GFP tag in human liver cell-lines in this study revealed that the C-terminus of HBx is indispensable for its specific localization in the mitochondria. A crucial region of seven amino acids at the C-terminus has been mapped out in which the cysteine residue at position 115 serves as the most important residue for the subcellular localization. When cysteine 115 of HBx is mutated to alanine the mitochondria targeting property of HBx is abrogated

  1. Metabolism of cysteine and cysteinesulfinate in rat kidney tubules

    International Nuclear Information System (INIS)

    De La Rosa, J.; Stipanuk, M.H.

    1986-01-01

    In studies with rat hepatocytes, hypotaurine plus taurine production accounted for less than 5% of the total amount of cysteine (CYS) catabolized, whereas more than 90% of the metabolized cysteinesulfinate (CSA) was converted to taurine plus hypotaurine. Similar studies have been carried out with kidney tubules isolated from fed rats and incubated with 2 mM [1- 14 C]CYS or 25 mM [1- 14 C]CSA at 37 0 C for up to 40 min. The production of 14 CO 2 from CSA (3.1 +/- 1.3 nmol/sup ./ min -1 /sup ./ mg dry wt -1 ) was equivalent to the accumulation of N in NH 4 + plus glutamate. Substantial oxidation of CYS was observed (16 +/- 11 nmol CO 2 x min -1 x mg dry wt -1 ), but only 12% of the expected amount of N was recovered as NH 4 + plus glutamate. Accumulation of hypotaurine plus taurine was equivalent to 20% of the observed rate of 14 CO 2 production from CSA but accounted for only 2% of the observed rate of 14 CO 2 production from CYS. Addition of unlabeled CSA to incubations with varying levels of CYS had no effect on production of 14 CO 2 . Addition of 2 mM α-ketoglutarate to the incubation mixtures resulted in an increased in 14 CO 2 production from CSA to 290% of the control level but had no effect on CYS oxidation. In agreement with the authors findings for rat hepatocytes, these data suggest that most metabolism of CYS by the rat kidney tubule occurs by a CSA-independent pathway. However, in contrast to the metabolism of CSA almost entirely to taurine in the hepatocyte, kidney tubules appeared to metabolize CSA primarily by the transamination pathway

  2. Preparation, Crystallization and X-ray Diffraction Analysis to 1.5 A Resolution of Rat Cysteine Dioxygenase, a Mononuclear Iron Enzyme Responsible for Cysteine Thiol Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons,C.; Hao, Q.; Stipanuk, M.

    2005-01-01

    Cysteine dioxygenase (CDO; EC 1.13.11.20) is an {approx}23 kDa non-heme iron metalloenzyme that is responsible for the oxidation of cysteine by O2, yielding cysteinesulfinate. CDO catalyzes the first step in the conversion of cysteine to taurine, as well as the first step in the catabolism of cysteine to pyruvate plus sulfate. Recombinant rat CDO was heterologously expressed, purified and crystallized. The protein was expressed as a fusion protein bearing a polyhistidine tag to facilitate purification, a thioredoxin tag to improve solubility and a factor Xa cleavage site to permit removal of the entire N-terminus, leaving only the 200 amino acids inherent to the native protein. A multi-step purification scheme was used to achieve >95% purity of CDO. The optimal CDO crystals diffracted to 1.5 Angstroms resolution and belonged to space group P4{sub 3}2{sub 1}2 or P4{sub 1}2{sub 1}2, with unit-cell parameters a = b = 57.55, c = 123.06 Angstrom, {alpha} = {beta} = {gamma} = 90. CDO shows little homology to any other proteins; therefore, the structure of the enzyme will be determined by ab initio phasing using a selenomethionyl derivative.

  3. Evaluation of the Effects of S-Allyl-L-cysteine, S-Methyl-L-cysteine, trans-S-1-Propenyl-L-cysteine, and Their N-Acetylated and S-Oxidized Metabolites on Human CYP Activities.

    Science.gov (United States)

    Amano, Hirotaka; Kazamori, Daichi; Itoh, Kenji

    2016-01-01

    Three major organosulfur compounds of aged garlic extract, S-allyl-L-cysteine (SAC), S-methyl-L-cysteine (SMC), and trans-S-1-propenyl-L-cysteine (S1PC), were examined for their effects on the activities of five major isoforms of human CYP enzymes: CYP1A2, 2C9, 2C19, 2D6, and 3A4. The metabolite formation from probe substrates for the CYP isoforms was examined in human liver microsomes in the presence of organosulfur compounds at 0.01-1 mM by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Allicin, a major component of garlic, inhibited CYP1A2 and CYP3A4 activity by 21-45% at 0.03 mM. In contrast, a CYP2C9-catalyzed reaction was enhanced by up to 1.9 times in the presence of allicin at 0.003-0.3 mM. SAC, SMC, and S1PC had no effect on the activities of the five isoforms, except that S1PC inhibited CYP3A4-catalyzed midazolam 1'-hydroxylation by 31% at 1 mM. The N-acetylated metabolites of the three compounds inhibited the activities of several isoforms to a varying degree at 1 mM. N-Acetyl-S-allyl-L-cysteine and N-acetyl-S-methyl-L-cysteine inhibited the reactions catalyzed by CYP2D6 and CYP1A2, by 19 and 26%, respectively, whereas trans-N-acetyl-S-1-propenyl-L-cysteine showed weak to moderate inhibition (19-49%) of CYP1A2, 2C19, 2D6, and 3A4 activities. On the other hand, both the N-acetylated and S-oxidized metabolites of SAC, SMC, and S1PC had little effect on the reactions catalyzed by the five isoforms. These results indicated that SAC, SMC, and S1PC have little potential to cause drug-drug interaction due to CYP inhibition or activation in vivo, as judged by their minimal effects (IC 50 >1 mM) on the activities of five major isoforms of human CYP in vitro.

  4. Management of NORM Residues

    International Nuclear Information System (INIS)

    2013-06-01

    The IAEA attaches great importance to the dissemination of information that can assist Member States in the development, implementation, maintenance and continuous improvement of systems, programmes and activities that support the nuclear fuel cycle and nuclear applications, and that address the legacy of past practices and accidents. However, radioactive residues are found not only in nuclear fuel cycle activities, but also in a range of other industrial activities, including: - Mining and milling of metalliferous and non-metallic ores; - Production of non-nuclear fuels, including coal, oil and gas; - Extraction and purification of water (e.g. in the generation of geothermal energy, as drinking and industrial process water; in paper and pulp manufacturing processes); - Production of industrial minerals, including phosphate, clay and building materials; - Use of radionuclides, such as thorium, for properties other than their radioactivity. Naturally occurring radioactive material (NORM) may lead to exposures at some stage of these processes and in the use or reuse of products, residues or wastes. Several IAEA publications address NORM issues with a special focus on some of the more relevant industrial operations. This publication attempts to provide guidance on managing residues arising from different NORM type industries, and on pertinent residue management strategies and technologies, to help Member States gain perspectives on the management of NORM residues

  5. Aggregation mechanism of Pd nanoparticles in L-cysteine aqueous solution studied by NEXAFS and AFM

    International Nuclear Information System (INIS)

    Tsukada, C.; Ogawa, S.; Mizutani, T.; Kutluk, G.; Namatame, H.; Taniguchi, M.; Yagi, S.

    2012-01-01

    Highlight: ► We focus on the biocompatibility of Pd nanoparticles (NPs) for L-cysteine under water environment. ► The Pd NPs have been fabricated and deposited on Si wafer by gas evaporation method. ► When the Pd NPs/Si has been dipped into L-cysteine aqueous solution, the L-cysteine has selectively adsorbed on Pd NPs surface and existed as the L-cysteine thiolate, atomic S and L-cystine. ► Moreover, the aggregation of Pd NPs occurs by the migration of Pd NPs on Si and the cross-linked reaction between L-cysteine thiolate molecules adsorbed on Pd NPs. - Abstract: We focus on the biocompatibility of Pd nanoparticles (NPs) from the point of microscopic view. Thus, as the basic research for the biocompatibility, we have investigated the adsorbates on the Pd NPs surface and the aggregation mechanism for the Pd NPs on Si substrate after dipping into L-cysteine aqueous solution by means of NEXAFS measurement and AFM observation. The Pd NPs have been fabricated and deposited on the Si wafer by the gas evaporation method. Judging from the results of NEXAFS measurement, it is clear that the L-cysteine thiolate and atomic S exist on the Pd NPs surface. The results of AFM observation show that the Pd NPs aggregate. It is thought that the aggregation of the Pd NPs occurs by both the migration of the Pd NPs on Si wafer and the cross-linked reaction.

  6. L-Cysteine Production in Escherichia coli Based on Rational Metabolic Engineering and Modular Strategy.

    Science.gov (United States)

    Liu, Han; Fang, Guochen; Wu, Hui; Li, Zhimin; Ye, Qin

    2018-05-01

    L-cysteine is an amino acid with important physiological functions and has a wide range of applications in medicine, food, animal feed, and cosmetics industry. In this study, the L-cysteine synthesis in Escherichia coliEscherichia coli is divided into four modules: the transport module, sulfur module, precursor module, and degradation module. The engineered strain LH03 (overexpression of the feedback-insensitive cysE and the exporter ydeD in JM109) accumulated 45.8 mg L -1 of L-cysteine in 48 hr with yield of 0.4% g/g glucose. Further modifications of strains and culture conditions which based on the rational metabolic engineering and modular strategy improved the L-cysteine biosynthesis significantly. The engineered strain LH06 (with additional overexpression of serA, serC, and serB and double mutant of tnaA and sdaA in LH03) produced 620.9 mg L -1 of L-cysteine with yield of 6.0% g/g glucose, which increased the production by 12 times and the yield by 14 times more than those of LH03 in the original condition. In fed-batch fermentation performed in a 5-L reactor, the concentration of L-cysteine achieved 5.1 g L -1 in 32 hr. This work demonstrates that the combination of rational metabolic engineering and module strategy is a promising approach for increasing the L-cysteine production in E. coli. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Dietary L-cysteine improves the antioxidative potential and lipid metabolism in rats fed a normal diet.

    Science.gov (United States)

    Lee, Seulki; Han, Kyu-Ho; Nakamura, Yumi; Kawakami, Sakura; Shimada, Ken-ichiro; Hayakawa, Touru; Onoue, Hirotake; Fukushima, Michihiro

    2013-01-01

    L-cysteine works as a precursor of the antioxidant, glutathione. We investigated the effects of L-cysteine (1% and 2%) on lipid metabolism and the antioxidative system in rats fed a normal diet. Administering L-cysteine dependently decreased the food intake, fat mass weight and body weight dose. Dietary L-cysteine also decreased the triglyceride levels in the serum and liver. However, there were no significant differences in the hepatic TBARS and glutathione (GSH) levels among the groups. The activities of catalase and glutathione reductase in the rats receiving 2% L-cysteine were significantly higher (pL-cysteine dose-dependently affected the antioxidative enzyme activities, and the lipid levels in the serum and liver which might be related to the reduced food intake.

  8. The Central Conserved Region (CCR) of Respiratory Syncytial Virus (RSV) G Protein Modulates Host miRNA Expression and Alters the Cellular Response to Infection.

    Science.gov (United States)

    Bakre, Abhijeet A; Harcourt, Jennifer L; Haynes, Lia M; Anderson, Larry J; Tripp, Ralph A

    2017-07-03

    Respiratory Syncytial Virus (RSV) infects respiratory epithelial cells and deregulates host gene expression by many mechanisms including expression of RSV G protein (RSV G). RSV G protein encodes a central conserved region (CCR) containing a CX3C motif that functions as a fractalkine mimic. Disruption of the CX3C motif (a.a. 182-186) located in the CCR of the G protein has been shown to affect G protein function in vitro and the severity of RSV disease pathogenesis in vivo. We show that infection of polarized Calu3 respiratory cells with recombinant RSV having point mutations in Cys173 and 176 (C173/176S) (rA2-GC12), or Cys186 (C186S) (rA2-GC4) is associated with a decline in the integrity of polarized Calu-3 cultures and decreased virus production. This is accompanied with downregulation of miRNAs let-7f and miR-24 and upregulation of interferon lambda (IFNλ), a primary antiviral cytokine for RSV in rA2-GC12/rA2-GC4 infected cells. These results suggest that residues in the cysteine noose region of RSV G protein can modulate IFN λ expression accompanied by downregulation of miRNAs, and are important for RSV G protein function and targeting.

  9. Activation of mas-related G-protein-coupled receptors by the house dust mite cysteine protease Der p1 provides a new mechanism linking allergy and inflammation.

    Science.gov (United States)

    Reddy, Vemuri B; Lerner, Ethan A

    2017-10-20

    Cysteine and serine proteases function via protease-activated and mas-related G-protein-coupled receptors (Mrgprs) to contribute to allergy and inflammation. Der p1 is a cysteine protease and major allergen from the house dust mite and is associated with allergic rhinitis and allergic asthma. Der p1 activates protease-activated receptor 2 and induces the release of the pro-inflammatory cytokine IL-6 from cells. However, the possibility that Der p1 acts on Mrgprs has not been considered. We report here that ratiometric calcium imaging reveals that Der p1 activates the human receptor MRGPRX1 and the mouse homolog MrgprC11, implicated previously in itch. Der p1 cleavage of N-terminal receptor peptides followed by site-directed mutagenesis of the cleavage sites links receptor activation to specific amino acid residues. Der p1 also induced the release of IL-6 from heterologous cells expressing MRGPRX1. In summary, activation of Mrgprs by the allergen Der p1 may contribute to inflammation. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Maize rayado fino virus virus-like particles expressed in tobacco plants: A new platform for cysteine selective bioconjugation peptide display.

    Science.gov (United States)

    Natilla, Angela; Hammond, Rosemarie W

    2011-12-01

    Maize rayado fino virus (MRFV) virus-like-particles (VLPs) produced in tobacco plants were examined for their ability to serve as a novel platform to which a variety of peptides can be covalently displayed when expressed through a Potato virus X (PVX)-based vector. To provide an anchor for chemical modifications, three Cys-MRFV-VLPs mutants were created by substituting several of the amino acids present on the shell of the wild-type MRFV-VLPs with cysteine residues. The mutant designated Cys 2-VLPs exhibited, under native conditions, cysteine thiol reactivity in bioconjugation reactions with a fluorescent dye. In addition, this Cys 2-VLPs was cross-linked by NHS-PEG4-Maleimide to 17 (F) and 8 (HN) amino acid long peptides, corresponding to neutralizing epitopes of Newcastle disease virus (NDV). The resulting Cys 2-VLPs-F and Cys 2-VLPs-HN were recognized in Western blots by antibodies to MRFV as well as to F and HN. The results demonstrated that plant-produced MRFV-VLPs have the ability to function as a novel platform for the multivalent display of surface ligands. Published by Elsevier B.V.

  11. Residual-stress measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ezeilo, A N; Webster, G A [Imperial College, London (United Kingdom); Webster, P J [Salford Univ. (United Kingdom)

    1997-04-01

    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author).

  12. The effect of L-cysteine on the portion-selective uptake of cadmium in the renal proximal tubule

    International Nuclear Information System (INIS)

    Murakami, Masataka; Sano, Kenichi; Webb, M.

    1987-01-01

    Cadmium (Cd), co-administered with an excess of L-cysteine, accumulates rapidly in the kidneys of the rat. After subcutaneous (s.c.) injection of 3 μmol CdCl 2 /kg body wt the concentrations of Cd in the blood and kidneys increase with the dose of cysteine over the range 0.06-5.0 mmol/kg body wt. At cysteine doses of less than 1.5 mmol/kg body wt the ratio of the concentrations of Cd in the outer medulla and cortex of the kidney remains the same as that after the injection of Cd alone. This ratio, however, is more than doubled at dose levels of 5-10 mmol cysteine/kg body wt. Hepatic uptake of Cd is unaffected by doses of cysteine below 1.5 mmol/kg body wt but decreases markedly at higher doses. In animals that are dosed simultaneously with 5 mmol cysteine/kg body wt, renal uptake of 109 Cd is known to occur in the straight segments of the proximal tubules. At a dose level of less than 1.5 mmol cysteine/kg body wt the present autoradiographical studies show that 109 Cd is taken up predominantly by the proximal convoluted tubules of the kidney cortex. At the critical dose level (1.5 mmol/kg body wt), cysteine decreases the retention of Cd at the s.c. injection site, but probably has little effect on the distribution of Cd between protein and other carrier molecules in the blood. This distribution, however, is altered at higher cysteine dose levels. It is suggested that, under the latter conditions, stable Cd-cysteine complexes are formed in the blood and are filtered readily through the glomeruli. These complexes are taken up in the kidney at the sites of cysteine reabsorption which, by studies with L-[ 35 S]-cysteine, are identified as the straight segments of the proximal tubules. (orig.)

  13. L-Cysteine and L-AP4 microinjections in the rat caudal ventrolateral medulla decrease arterial blood pressure.

    Science.gov (United States)

    Takemoto, Yumi

    2014-12-01

    The thiol amino acid L-cysteine increases arterial blood pressure (ABP) when injected into the cerebrospinal fluid space in conscious rats, indicating a pressor response to centrally acting L-cysteine. A prior synaptic membrane binding assay suggests that L-cysteine has a strong affinity for the L-2-amino-4-phosphonobutyric acid (L-AP4) binding site. The central action of L-cysteine may be vial-AP4 sensitive receptors. The present study investigated cardiovascular responses to L-cysteine and L-ap4 microinjected into the autonomic area of the caudal ventrolateral medulla (CVLM) where inhibitory neurons regulate ABP via pre-sympathetic vasomotor neurons. Both the injection of L-cysteine and L-AP4 in the CVLM sites identified with L-glutamate produced the same depressor and bradycardic responses in urethane-anesthetized rats. Neither a prior antagonist microinjection of MK801 for the N-methyl-D-aspartate (NMDA) receptor nor CNQX for the non-NMDA receptor attenuated the responses to L-cysteine, but the combination of the two receptor blocking with an additional prior injection abolished the response. In contrast, either receptor blockade alone abolished the response to L-AP4, indicating distinct mechanisms between responses to L-cysteine and L-AP4 in the CVLM. The results indicate that the CVLM is a central active site for L-cysteine's cardiovascular response. Central L-cysteine's action could be independent of the L-AP4 sensitive receptors. Cardiovascular regulation may involve endogenous L-cysteine in the CVLM. Further multidisciplinary examinations are required to elaborate on L-cysteine's functional roles in the CVLM. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Wetting of nonconserved residue-backbones: A feature indicative of aggregation associated regions of proteins.

    Science.gov (United States)

    Pradhan, Mohan R; Pal, Arumay; Hu, Zhongqiao; Kannan, Srinivasaraghavan; Chee Keong, Kwoh; Lane, David P; Verma, Chandra S

    2016-02-01

    Aggregation is an irreversible form of protein complexation and often toxic to cells. The process entails partial or major unfolding that is largely driven by hydration. We model the role of hydration in aggregation using "Dehydrons." "Dehydrons" are unsatisfied backbone hydrogen bonds in proteins that seek shielding from water molecules by associating with ligands or proteins. We find that the residues at aggregation interfaces have hydrated backbones, and in contrast to other forms of protein-protein interactions, are under less evolutionary pressure to be conserved. Combining evolutionary conservation of residues and extent of backbone hydration allows us to distinguish regions on proteins associated with aggregation (non-conserved dehydron-residues) from other interaction interfaces (conserved dehydron-residues). This novel feature can complement the existing strategies used to investigate protein aggregation/complexation. © 2015 Wiley Periodicals, Inc.

  15. Acetaminophen-cysteine adducts during therapeutic dosing and following overdose

    Directory of Open Access Journals (Sweden)

    Judge Bryan S

    2011-03-01

    Full Text Available Abstract Background Acetaminophen-cysteine adducts (APAP-CYS are a specific biomarker of acetaminophen exposure. APAP-CYS concentrations have been described in the setting of acute overdose, and a concentration >1.1 nmol/ml has been suggested as a marker of hepatic injury from acetaminophen overdose in patients with an ALT >1000 IU/L. However, the concentrations of APAP-CYS during therapeutic dosing, in cases of acetaminophen toxicity from repeated dosing and in cases of hepatic injury from non-acetaminophen hepatotoxins have not been well characterized. The objective of this study is to describe APAP-CYS concentrations in these clinical settings as well as to further characterize the concentrations observed following acetaminophen overdose. Methods Samples were collected during three clinical trials in which subjects received 4 g/day of acetaminophen and during an observational study of acetaminophen overdose patients. Trial 1 consisted of non-drinkers who received APAP for 10 days, Trial 2 consisted of moderate drinkers dosed for 10 days and Trial 3 included subjects who chronically abuse alcohol dosed for 5 days. Patients in the observational study were categorized by type of acetaminophen exposure (single or repeated. Serum APAP-CYS was measured using high pressure liquid chromatography with electrochemical detection. Results Trial 1 included 144 samples from 24 subjects; Trial 2 included 182 samples from 91 subjects and Trial 3 included 200 samples from 40 subjects. In addition, we collected samples from 19 subjects with acute acetaminophen ingestion, 7 subjects with repeated acetaminophen exposure and 4 subjects who ingested another hepatotoxin. The mean (SD peak APAP-CYS concentrations for the Trials were: Trial 1- 0.4 (0.20 nmol/ml, Trial 2- 0.1 (0.09 nmol/ml and Trial 3- 0.3 (0.12 nmol/ml. APAP-CYS concentrations varied substantially among the patients with acetaminophen toxicity (0.10 to 27.3 nmol/ml. No subject had detectable APAP

  16. Experimental and theoretical investigation on corrosion inhibition of AA5052 aluminium alloy by L-cysteine in alkaline solution

    International Nuclear Information System (INIS)

    Wang, Dapeng; Gao, Lixin; Zhang, Daquan; Yang, Dong; Wang, Hongxia; Lin, Tong

    2016-01-01

    The corrosion inhibition of L-cysteine on AA5052 aluminium alloy in 4 mol/L NaOH solution was investigated by hydrogen gas evolution experiment, polarisation curve, galvanostatic discharge, electrochemical impedance spectroscopy measurements and quantum chemical calculations. The adsorption of L-cysteine on aluminium alloy surface obeyed the amended Langmuir's adsorption isotherm. The polarisation curves indicated that L-cysteine acted as a cathodic inhibitor to inhibit cathodic reaction. The inhibition mechanism was dominated by the geometric covering effect. The galvanostatic discharge shows that the additives restrain the hydrogen evolution and increase the anodic utilization rate. Quantum chemical calculations indicated that L-cysteine molecules mainly interacted with on the carboxyl groups on the aluminium alloy surface. A strong hybridization occurred between the s-orbital and p-orbital of reactive sites in the L-cysteine molecule and the sp-orbital of Aluminium. - Highlights: • L-cysteine was used as corrosion inhibitor for Al alloy in alkaline solution. • Adsorption of L-cysteine on Al alloy surface obeyed the amended Langmuir's isotherm. • L-cysteine molecules interacted with the carboxyl groups on the Al alloy surface. • A strong orbital hybridization occurred between the reactive sites in L-cysteine and Al.

  17. Pressor response to L-cysteine injected into the cisterna magna of conscious rats involves recruitment of hypothalamic vasopressinergic neurons.

    Science.gov (United States)

    Takemoto, Yumi

    2013-03-01

    The sulfur-containing non-essential amino acid L-cysteine injected into the cisterna magna of adult conscious rats produces an increase in blood pressure. The present study examined if the pressor response to L-cysteine is stereospecific and involves recruitment of hypothalamic vasopressinergic neurons and medullary noradrenergic A1 neurons. Intracisternally injected D-cysteine produced no cardiovascular changes, while L-cysteine produced hypertension and tachycardia in freely moving rats, indicating the stereospecific hemodynamic actions of L-cysteine via the brain. The double labeling immunohistochemistry combined with c-Fos detection as a marker of neuronal activation revealed significantly higher numbers of c-Fos-positive vasopressinergic neurons both in the supraoptic and paraventricular nuclei and tyrosine hydroxylase containing medullary A1 neurons, of L-cysteine-injected rats than those injected with D-cysteine as iso-osmotic control. The results indicate that the cardiovascular responses to intracisternal injection of L-cysteine in the conscious rat are stereospecific and include recruitment of hypothalamic vasopressinergic neurons both in the supraoptic and paraventricular nuclei, as well as of medullary A1 neurons. The findings may suggest a potential function of L-cysteine as an extracellular signal such as neuromodulators in central regulation of blood pressure.

  18. Experimental and theoretical investigation on corrosion inhibition of AA5052 aluminium alloy by L-cysteine in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dapeng; Gao, Lixin [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Zhang, Daquan, E-mail: zhangdaquan@shiep.edu.cn [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Yang, Dong [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Wang, Hongxia; Lin, Tong [Institute for Frontier Materials, Deakin University, Geelong, VIC 3216 (Australia)

    2016-02-01

    The corrosion inhibition of L-cysteine on AA5052 aluminium alloy in 4 mol/L NaOH solution was investigated by hydrogen gas evolution experiment, polarisation curve, galvanostatic discharge, electrochemical impedance spectroscopy measurements and quantum chemical calculations. The adsorption of L-cysteine on aluminium alloy surface obeyed the amended Langmuir's adsorption isotherm. The polarisation curves indicated that L-cysteine acted as a cathodic inhibitor to inhibit cathodic reaction. The inhibition mechanism was dominated by the geometric covering effect. The galvanostatic discharge shows that the additives restrain the hydrogen evolution and increase the anodic utilization rate. Quantum chemical calculations indicated that L-cysteine molecules mainly interacted with on the carboxyl groups on the aluminium alloy surface. A strong hybridization occurred between the s-orbital and p-orbital of reactive sites in the L-cysteine molecule and the sp-orbital of Aluminium. - Highlights: • L-cysteine was used as corrosion inhibitor for Al alloy in alkaline solution. • Adsorption of L-cysteine on Al alloy surface obeyed the amended Langmuir's isotherm. • L-cysteine molecules interacted with the carboxyl groups on the Al alloy surface. • A strong orbital hybridization occurred between the reactive sites in L-cysteine and Al.

  19. Conservation: Toward firmer ground

    Science.gov (United States)

    1975-01-01

    The following aspects of energy conservation were reviewed in order to place the problems in proper perspective: history and goals, conservation accounting-criteria, and a method to overcome obstacles. The effect of changing prices and available supplies of energy sources and their causes on consumption levels during the last few decades were described. Some examples of attainable conservation goals were listed and justified. A number of specific criteria applicable to conservation accounting were given. Finally, a discussion was presented to relate together the following aspects of energy conservation: widespread impact, involvement of government, industry, politics, moral and ethical aspects, urgency and time element.

  20. Cysteine-mediated gene expression and characterization of the CmbR regulon in Streptococcus pneumoniae

    Directory of Open Access Journals (Sweden)

    Muhammad Afzal

    2016-12-01

    Full Text Available In this study, we investigated the transcriptomic response of Streptococcus pneumoniae D39 to cysteine. Transcriptome comparison of the D39 wild-type strain grown at a restricted concentration of cysteine (0.03 mM to one grown at a high concentration of cysteine (50 mM in chemically-define medium (CDM revealed elevated expression of various genes/operons, i.e. spd-0150, metQ, spd-0431, metEF, gshT, spd-0618, fhs, tcyB, metB-csd, metA, spd-1898, yvdE, and cysK, likely to be involved in the transport and utilization of cysteine and/or methionine. Microarray-based data were further confirmed by quantitative RT-PCR. Promoter lacZ-fusion studies and quantitative RT-PCR data showed that the transcriptional regulator CmbR acts as a transcriptional repressor of spd-0150, metEF, gshT, spd-0618, tcyB, metA, and yvdE, putatively involved in cysteine uptake and utilization. The operator site of CmbR in the promoter regions of CmbR-regulated genes is predicted and confirmed by mutating or deleting CmbR operator sites from the promoter regions of these genes.

  1. Identification of semicarbazones, thiosemicarbazones and triazine nitriles as inhibitors of Leishmania mexicana cysteine protease CPB.

    Directory of Open Access Journals (Sweden)

    Jörg Schröder

    Full Text Available Cysteine proteases of the papain superfamily are present in nearly all eukaryotes. They play pivotal roles in the biology of parasites and inhibition of cysteine proteases is emerging as an important strategy to combat parasitic diseases such as sleeping sickness, Chagas' disease and leishmaniasis. Homology modeling of the mature Leishmania mexicana cysteine protease CPB2.8 suggested that it differs significantly from bovine cathepsin B and thus could be a good drug target. High throughput screening of a compound library against this enzyme and bovine cathepsin B in a counter assay identified four novel inhibitors, containing the warhead-types semicarbazone, thiosemicarbazone and triazine nitrile, that can be used as leads for antiparasite drug design. Covalent docking experiments confirmed the SARs of these lead compounds in an effort to understand the structural elements required for specific inhibition of CPB2.8. This study has provided starting points for the design of selective and highly potent inhibitors of L. mexicana cysteine protease CPB that may also have useful efficacy against other important cysteine proteases.

  2. Selective chromogenic and fluorogenic peptide substrates for the assay of cysteine peptidases in complex mixtures.

    Science.gov (United States)

    Semashko, Tatiana A; Vorotnikova, Elena A; Sharikova, Valeriya F; Vinokurov, Konstantin S; Smirnova, Yulia A; Dunaevsky, Yakov E; Belozersky, Mikhail A; Oppert, Brenda; Elpidina, Elena N; Filippova, Irina Y

    2014-03-15

    This study describes the design, synthesis, and use of selective peptide substrates for cysteine peptidases of the C1 papain family, important in many biological processes. The structure of the newly synthesized substrates is Glp-Xaa-Ala-Y (where Glp=pyroglutamyl; Xaa=Phe or Val; and Y=pNA [p-nitroanilide], AMC [4-amino-7-methylcoumaride], or AFC [4-amino-7-trifluoromethyl-coumaride]). Substrates were synthesized enzymatically to guarantee selectivity of the reaction and optical purity of the target compounds, simplifying the scheme of synthesis and isolation of products. The hydrolysis of the synthesized substrates was evaluated by C1 cysteine peptidases from different organisms and with different functions, including plant enzymes papain, bromelain, ficin, and mammalian lysosomal cathepsins B and L. The new substrates were selective for C1 cysteine peptidases and were not hydrolyzed by serine, aspartic, or metallo peptidases. We demonstrated an application of the selectivity of the synthesized substrates during the chromatographic separation of a multicomponent set of digestive peptidases from a beetle, Tenebrio molitor. Used in combination with the cysteine peptidase inhibitor E-64, these substrates were able to differentiate cysteine peptidases from peptidases of other classes in midgut extracts from T. molitor larvae and larvae of the genus Tribolium; thus, they are useful in the analysis of complex mixtures containing peptidases from different classes. Published by Elsevier Inc.

  3. Electronic structures of the L-cysteine film on dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K., E-mail: e7141@cc.saga-u.ac.jp [Synchrotron Light Application Center, Saga University, Saga 840-8502 (Japan); Tsujibayashi, T. [Department of Physics, Osaka Dental University, Osaka 573-1121 (Japan); Takahashi, K.; Azuma, J. [Synchrotron Light Application Center, Saga University, Saga 840-8502 (Japan); Kakimoto, K. [Department of Geriatric Dentistry, Osaka Dental University, Osaka 573-1121 (Japan); Kamada, M. [Synchrotron Light Application Center, Saga University, Saga 840-8502 (Japan)

    2011-04-15

    Research highlights: {yields} The electronic structures of dental alloys and L-cysteine film were studied by PES. {yields} The density of states in the dental alloy originates from Au and Cu as constituents. {yields} The Cu-3d states contribute dominantly to the occupied states near the Fermi level. {yields} The electronic structure of L-cysteine thin film is different from the thick film. {yields} The bonding between Cu-3d and S-3sp states are formed at the interface. - Abstract: Metal-organic interfaces have been attracting continuous attention in many fields including basic biosciences. The surface of dental alloys could be one of such interfaces since they are used in a circumstance full of organic compounds such as proteins and bacteria. In this work, electronic structures of Au-dominant dental alloys, which have Ag and Cu besides Au, and those of L-cysteine on the dental alloys have been studied by photoelectron spectroscopy with synchrotron radiation. It was found that the density of states in the dental alloy originate from gold and copper as constituents, and the Cu-3d states contribute dominantly to the occupied states near the Fermi level. It was also found that the electronic structure of the L-cysteine thin film on the dental alloy is different from that of the L-cysteine thick film. The result indicates the formation of the orbital bonding between Cu-3d and S-3sp states in the thin film on the dental alloy.

  4. Electronic structures of the L-cysteine film on dental alloys

    International Nuclear Information System (INIS)

    Ogawa, K.; Tsujibayashi, T.; Takahashi, K.; Azuma, J.; Kakimoto, K.; Kamada, M.

    2011-01-01

    Research highlights: → The electronic structures of dental alloys and L-cysteine film were studied by PES. → The density of states in the dental alloy originates from Au and Cu as constituents. → The Cu-3d states contribute dominantly to the occupied states near the Fermi level. → The electronic structure of L-cysteine thin film is different from the thick film. → The bonding between Cu-3d and S-3sp states are formed at the interface. - Abstract: Metal-organic interfaces have been attracting continuous attention in many fields including basic biosciences. The surface of dental alloys could be one of such interfaces since they are used in a circumstance full of organic compounds such as proteins and bacteria. In this work, electronic structures of Au-dominant dental alloys, which have Ag and Cu besides Au, and those of L-cysteine on the dental alloys have been studied by photoelectron spectroscopy with synchrotron radiation. It was found that the density of states in the dental alloy originate from gold and copper as constituents, and the Cu-3d states contribute dominantly to the occupied states near the Fermi level. It was also found that the electronic structure of the L-cysteine thin film on the dental alloy is different from that of the L-cysteine thick film. The result indicates the formation of the orbital bonding between Cu-3d and S-3sp states in the thin film on the dental alloy.

  5. Cysteine proteases: Modes of activation and future prospects as pharmacological targets

    Directory of Open Access Journals (Sweden)

    Sonia eVerma

    2016-04-01

    Full Text Available Proteolytic enzymes are crucial for a variety of biological processes in organisms ranging from lower (virus, bacteria and parasite to the higher organisms (mammals. Proteases cleave proteins into smaller fragments by catalyzing peptide bonds hydrolysis. Proteases are classified according to their catalytic site, and distributed into four major classes: cysteine proteases, serine proteases, aspartic proteases and metallo-proteases. This review will cover only cysteine proteases, papain family enzymes which are involved in multiple functions such as extracellular matrix turnover, antigen presentation, processing events, digestion, immune invasion, hemoglobin hydrolysis, parasite invasion, parasite egress and processing surface proteins. Therefore, they are promising drug targets for various diseases. For preventing unwanted digestion, cysteine proteases are synthesized as zymogens, and contain a pro-domain (regulatory and a mature domain (catalytic. The prodomain acts as an endogenous inhibitor of the mature enzyme. For activation of the mature enzyme, removal of the prodomain is necessary and achieved by different modes. The pro-mature domain interaction can be categorized as protein-protein interactions (PPIs and may be targeted in a range of diseases. Cysteine protease inhibitors are available that can block the active site but no such inhibitor available yet that can be targeted to block the pro-mature domain interactions and prevent it activation. This review specifically highlights the modes of activation (processing of papain family enzymes, which involve auto-activation, trans-activation and also clarifies the future aspects of targeting PPIs to prevent the activation of cysteine proteases.

  6. The effect of cysteine on the corrosion of 304L stainless steel in sulphuric acid

    International Nuclear Information System (INIS)

    Silva, A.B.; Agostinho, S.M.L.; Barcia, O.E.; Cordeiro, G.G.O.; D'Elia, E.

    2006-01-01

    The effect of cysteine on the corrosion of 304L stainless steel in 1 mol l -1 H 2 SO 4 was studied using open-circuit potential measurements, anodic polarization curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). All the electrochemical measurements obtained in the presence of low cysteine concentration (10 -6 -10 -5 mol l -1 ) presented the same behaviour as those obtained in the absence of cysteine, a passivated steel surface. However, for higher cysteine concentrations (10 -4 -10 -2 mol l -1 ), a different behaviour was observed: the corrosion potential stabilized at a more negative value; an active region was observed in the anodic polarization curves and the electrochemical impedance diagrams showed an inductive loop at lower frequencies and a much lower polarization resistance. These results show that the presence of cysteine at high concentration turns the surface of 304L stainless steel electrochemically active, probably dissolving the passivation layer and promoting the stainless steel anodic dissolution. SEM experiments performed after immersion experiments at corrosion potential were in good agreement with the electrochemical results

  7. Effects of L-cysteine on lead acetate induced neurotoxicity in albino mice.

    Science.gov (United States)

    Mahmoud, Y I; Sayed, S S

    2016-07-01

    Lead is a toxic heavy metal that adversely affects nervous tissues; it often occurs as an environmental pollutant. We investigated histological changes in the cerebral cortex, hippocampus and cerebellum of adult albino mice following exposure to lead acetate. We also studied the possible ameliorative effect of the chelating agent, L-cysteine, on lead-induced neurotoxicity. We divided albino mice into six groups: 1) vehicle-only control, 2) L-cysteine control, 3 and 4) treated for 7 days with 20 and 40 mg/kg lead acetate, respectively, and 5 and 6) treated for 7 days with 20 and 40 mg/kg lead acetate, respectively, followed by 50 mg/kg L-cysteine for 7 days. Lead acetate administration caused disorganization of cell layers, neuronal loss and degeneration, and neuropil vacuolization. Brain sections from lead-intoxicated mice treated with L-cysteine showed fewer pathological changes; the neuropil showed less vacuolization and the neurons appeared less damaged. L-cysteine at the dose we used only marginally alleviated lead-induced toxicity.

  8. Cysteine Cathepsins as Regulators of the Cytotoxicity of NK and T Cells

    Science.gov (United States)

    Perišić Nanut, Milica; Sabotič, Jerica; Jewett, Anahid; Kos, Janko

    2014-01-01

    Cysteine cathepsins are lysosomal peptidases involved at different levels in the processes of the innate and adaptive immune responses. Some, such as cathepsins B, L, and H are expressed constitutively in most immune cells. In cells of innate immunity they play a role in cell adhesion and phagocytosis. Other cysteine cathepsins are expressed more specifically. Cathepsin X promotes dendritic cell maturation, adhesion of macrophages, and migration of T cells. Cathepsin S is implicated in major histocompatibility complex class II antigen presentation, whereas cathepsin C, expressed in cytotoxic T lymphocytes and natural killer (NK) cells, is involved in processing pro-granzymes into proteolytically active forms, which trigger cell death in their target cells. The activity of cysteine cathepsins is controlled by endogenous cystatins, cysteine protease inhibitors. Of these, cystatin F is the only cystatin that is localized in endosomal/lysosomal vesicles. After proteolytic removal of its N-terminal peptide, cystatin F becomes a potent inhibitor of cathepsin C with the potential to regulate pro-granzyme processing and cell cytotoxicity. This review is focused on the role of cysteine cathepsins and their inhibitors in the molecular mechanisms leading to the cytotoxic activity of T lymphocytes and NK cells in order to address new possibilities for regulation of their function in pathological processes. PMID:25520721

  9. Identification of pH-sensitive regions in the mouse prion by the cysteine-scanning spin-labeling ESR technique

    International Nuclear Information System (INIS)

    Watanabe, Yasuko; Inanami, Osamu; Horiuchi, Motohiro; Hiraoka, Wakako; Shimoyama, Yuhei; Inagaki, Fuyuhiko; Kuwabara, Mikinori

    2006-01-01

    We analyzed the pH-induced mobility changes in moPrP C α-helix and β-sheets by cysteine-scanning site-directed spin labeling (SDSL) with ESR. Nine amino acid residues of α-helix1 (H1, codon 143-151), four amino acid residues of β-sheet1 (S1, codon 127-130), and four amino acid residues of β-sheet2 (S2, codon 160-163) were substituted for by cysteine residues. These recombinant mouse PrP C (moPrP C ) mutants were reacted with a methane thiosulfonate sulfhydryl-specific spin labeling reagent (MTSSL). The 1/δH of the central ( 14 N hyperfine) component (M I = 0) in the ESR spectrum of spin-labeled moPrP C was measured as a mobility parameter of nitroxide residues (R1). The mobilities of E145R1 and Y149R1 at pH 7.4, which was identified as a tertiary contact site by a previous NMR study of moPrP, were lower than those of D143R1, R147R1, and R150R1 reported on the helix surface. Thus, the mobility in the H1 region in the neutral solution was observed with the periodicity associated with a helical structure. On the other hand, the values in the S2 region, known to be located in the buried side, were lower than those in the S1 region located in the surface side. These results indicated that the mobility parameter of the nitroxide label was well correlated with the 3D structure of moPrP. Furthermore, the present study clearly demonstrated three pH-sensitive sites in moPrP, i.e. (1) the N-terminal tertiary contact site of H1 (2) the C-terminal end of H1, and (3) the S2 region. In particular, among these pH-sensitive sites, the N-terminal tertiary contact region of H1 was found to be the most pH-sensitive one and was easily converted to a flexible structure by a slight decrease of pH in the solution. These data provided molecular evidence to explain the cellular mechanism for conversion from PrP C to PrP Sc in acidic organelles such as the endosome

  10. Selenoproteins-What unique properties can arise with selenocysteine in place of cysteine?

    Science.gov (United States)

    Arnér, Elias S J

    2010-05-01

    The defining entity of a selenoprotein is the inclusion of at least one selenocysteine (Sec) residue in its sequence. Sec, the 21st naturally occurring genetically encoded amino acid, differs from its significantly more common structural analog cysteine (Cys) by the identity of a single atom: Sec contains selenium instead of the sulfur found in Cys. Selenium clearly has unique chemical properties that differ from sulfur, but more striking are perhaps the similarities between the two elements. Selenium was discovered by Jöns Jacob Berzelius, a renowned Swedish scientist instrumental in establishing the institution that would become Karolinska Institutet. Written at the occasion of the bicentennial anniversary of Karolinska Institutet, this mini review focuses on the unique selenium-derived properties that may potentially arise in a protein upon the inclusion of Sec in place of Cys. With 25 human genes encoding selenoproteins and in total several thousand selenoproteins yet described in nature, it seems likely that the presence of that single selenium atom of Sec should convey some specific feature, thereby explaining the existence of selenoproteins in spite of demanding and energetically costly Sec-specific synthesis machineries. Nonetheless, most, if not all, of the currently known selenoproteins are also found as Cys-containing non-selenoprotein orthologues in other organisms, wherefore any potentially unique properties of selenoproteins are yet a matter of debate. The pK(a) of free Sec (approximately 5.2) being significantly lower than that of free Cys (approximately 8.5) has often been proposed as one of the unique features of Sec. However, as discussed herein, this pK(a) difference between Sec and Cys can hardly provide an evolutionary pressure for maintenance of selenoproteins. Moreover, the typically 10- to 100-fold lower enzymatic efficiencies of Sec-to-Cys mutants of selenoprotein oxidoreductases, are also weak arguments for the overall existence of

  11. Designing with residual materials

    NARCIS (Netherlands)

    Walhout, W.; Wever, R.; Blom, E.; Addink-Dölle, L.; Tempelman, E.

    2013-01-01

    Many entrepreneurial businesses have attempted to create value based on the residual material streams of third parties. Based on ‘waste’ materials they designed products, around which they built their company. Such activities have the potential to yield sustainable products. Many of such companies

  12. Cysteine Specific Targeting of the Functionally Distinct Peroxiredoxin and Glutaredoxin Proteins by the Investigational Disulfide BNP7787

    Directory of Open Access Journals (Sweden)

    Aulma R. Parker

    2015-03-01

    Full Text Available Glutaredoxin (Grx, peroxiredoxin (Prx, and thioredoxin (Trx are redoxin family proteins that catalyze different types of chemical reactions that impact cell growth and survival through functionally distinct intracellular pathways. Much research is focused on understanding the roles of these redoxin proteins in the development and/or progression of human diseases. Grx and Prx are overexpressed in human cancers, including human lung cancers. BNP7787 is a novel investigational agent that has been evaluated in previous clinical studies, including non-small cell lung cancer (NSCLC studies. Herein, data from activity assays, mass spectrometry analyses, and X-ray crystallographic studies indicate that BNP7787 forms mixed disulfides with select cysteine residues on Grx and Prx and modulates their function. Studies of interactions between BNP7787 and Trx have been conducted and reported separately. Despite the fact that Trx, Grx, and Prx are functionally distinct proteins that impact oxidative stress, cell proliferation and disease processes through different intracellular pathways, BNP7787 can modify each protein and appears to modulate function through mechanisms that are unique to each target protein. Tumor cells are often genomically heterogeneous containing subpopulations of cancer cells that often express different tumor-promoting proteins or that have multiple dysregulated signaling pathways modulating cell proliferation and drug resistance. A multi-targeted agent that simultaneously modulates activity of proteins important in mediating cell proliferation by functionally distinct intracellular pathways could have many potentially useful therapeutic applications.

  13. Cy-preds: An algorithm and a web service for the analysis and prediction of cysteine reactivity.

    Science.gov (United States)

    Soylu, İnanç; Marino, Stefano M

    2016-02-01

    Cysteine (Cys) is a critically important amino acid, serving a variety of functions within proteins including structural roles, catalysis, and regulation of function through post-translational modifications. Predicting which Cys residues are likely to be reactive is a very sought after feature. Few methods are currently available for the task, either based on evaluation of physicochemical features (e.g., pKa and exposure) or based on similarity with known instances. In this study, we developed an algorithm (named HAL-Cy) which blends previous work with novel implementations to identify reactive Cys from nonreactive. HAL-Cy present two major components: (i) an energy based part, rooted on the evaluation of H-bond network contributions and (ii) a knowledge based part, composed of different profiling approaches (including a newly developed weighting matrix for sequence profiling). In our evaluations, HAL-Cy provided significantly improved performances, as tested in comparisons with existing approaches. We implemented our algorithm in a web service (Cy-preds), the ultimate product of our work; we provided it with a variety of additional features, tools, and options: Cy-preds is capable of performing fully automated calculations for a thorough analysis of Cys reactivity in proteins, ranging from reactivity predictions (e.g., with HAL-Cy) to functional characterization. We believe it represents an original, effective, and very useful addition to the current array of tools available to scientists involved in redox biology, Cys biochemistry, and structural bioinformatics. © 2015 Wiley Periodicals, Inc.

  14. Spectroscopic investigations on the effect of N-Acetyl-L-cysteine-Capped CdTe Quantum Dots on catalase

    Science.gov (United States)

    Sun, Haoyu; Yang, Bingjun; Cui, Erqian; Liu, Rutao

    2014-11-01

    Quantum dots (QDs) are recognized as some of the most promising semiconductor nanocrystals in biomedical applications. However, the potential toxicity of QDs has aroused wide public concern. Catalase (CAT) is a common enzyme in animal and plant tissues. For the potential application of QDs in vivo, it is important to investigate the interaction of QDs with CAT. In this work, the effect of N-Acetyl-L-cysteine-Capped CdTe Quantum Dots with fluorescence emission peak at 612 nm (QDs-612) on CAT was investigated by fluorescence, synchronous fluorescence, fluorescence lifetime, ultraviolet-visible (UV-vis) absorption and circular dichroism (CD) techniques. Binding of QDs-612 to CAT caused static quenching of the fluorescence, the change of the secondary structure of CAT and the alteration of the microenvironment of tryptophan residues. The association constants K were determined to be K288K = 7.98 × 105 L mol-1 and K298K = 7.21 × 105 L mol-1. The interaction between QDs-612 and CAT was spontaneous with 1:1 stoichiometry approximately. The CAT activity was also inhibited for the bound QDs-612. This work provides direct evidence about enzyme toxicity of QDs-612 to CAT in vitro and establishes a new strategy to investigate the interaction between enzyme and QDs at a molecular level, which is helpful for clarifying the bioactivities of QDs in vivo.

  15. Roles of conserved ectodomain cysteines of the rat P2X4 purinoreceptor in agonist binding and channel gating

    Czech Academy of Sciences Publication Activity Database

    Rokic, Milos Boro; Tvrdoňová, Vendula; Vávra, Vojtěch; Jindřichová, Marie; Obšil, T.; Stojilkovic, S. S.; Zemková, Hana

    2010-01-01

    Roč. 59, č. 6 (2010), s. 927-935 ISSN 0862-8408 R&D Projects: GA AV ČR(CZ) IAA500110910; GA ČR(CZ) GA305/07/0681; GA MŠk(CZ) LC554 Institutional research plan: CEZ:AV0Z50110509 Keywords : P2X4 receptor * ATP * disulfide bonds Subject RIV: ED - Physiology Impact factor: 1.646, year: 2010

  16. Folding machineries displayed on a cation-exchanger for the concerted refolding of cysteine- or proline-rich proteins

    Directory of Open Access Journals (Sweden)

    Lee Dae-Hee

    2009-03-01

    Full Text Available Abstract Background Escherichia coli has been most widely used for the production of valuable recombinant proteins. However, over-production of heterologous proteins in E. coli frequently leads to their misfolding and aggregation yielding inclusion bodies. Previous attempts to refold the inclusion bodies into bioactive forms usually result in poor recovery and account for the major cost in industrial production of desired proteins from recombinant E. coli. Here, we describe the successful use of the immobilized folding machineries for in vitro refolding with the examples of high yield refolding of a ribonuclease A (RNase A and cyclohexanone monooxygenase (CHMO. Results We have generated refolding-facilitating media immobilized with three folding machineries, mini-chaperone (a monomeric apical domain consisting of residues 191–345 of GroEL and two foldases (DsbA and human peptidyl-prolyl cis-trans isomerase by mimicking oxidative refolding chromatography. For efficient and simple purification and immobilization simultaneously, folding machineries were fused with the positively-charged consecutive 10-arginine tag at their C-terminal. The immobilized folding machineries were fully functional when assayed in a batch mode. When the refolding-facilitating matrices were applied to the refolding of denatured and reduced RNase A and CHMO, both of which contain many cysteine and proline residues, RNase A and CHMO were recovered in 73% and 53% yield of soluble protein with full enzyme activity, respectively. Conclusion The refolding-facilitating media presented here could be a cost-efficient platform and should be applicable to refold a wide range of E. coli inclusion bodies in high yield with biological function.

  17. Differential processing of Arabidopsis ubiquitin-like Atg8 autophagy proteins by Atg4 cysteine proteases

    Science.gov (United States)

    Woo, Jongchan; Park, Eunsook; Dinesh-Kumar, S. P.

    2014-01-01

    Autophagy is a highly conserved biological process during which double membrane bound autophagosomes carry intracellular cargo material to the vacuole or lysosome for degradation and/or recycling. Autophagosome biogenesis requires Autophagy 4 (Atg4) cysteine protease-mediated processing of ubiquitin-like Atg8 proteins. Unlike single Atg4 and Atg8 genes in yeast, the Arabidopsis genome contains two Atg4 (AtAtg4a and AtAtg4b) and nine Atg8 (AtAtg8a–AtAtg8i) genes. However, we know very little about specificity of different AtAtg4s for processing of different AtAtg8s. Here, we describe a unique bioluminescence resonance energy transfer-based AtAtg8 synthetic substrate to assess AtAtg4 activity in vitro and in vivo. In addition, we developed a unique native gel assay of superhRLUC catalytic activity assay to monitor cleavage of AtAtg8s in vitro. Our results indicate that AtAtg4a is the predominant protease and that it processes AtAtg8a, AtAtg8c, AtAtg8d, and AtAtg8i better than AtAtg4b in vitro. In addition, kinetic analyses indicate that although both AtAtg4s have similar substrate affinity, AtAtg4a is more active than AtAtg4b in vitro. Activity of AtAtg4s is reversibly inhibited in vitro by reactive oxygen species such as H2O2. Our in vivo bioluminescence resonance energy transfer analyses in Arabidopsis transgenic plants indicate that the AtAtg8 synthetic substrate is efficiently processed and this is AtAtg4 dependent. These results indicate that the synthetic AtAtg8 substrate is used efficiently in the biogenesis of autophagosomes in vivo. Transgenic Arabidopsis plants expressing the AtAtg8 synthetic substrate will be a valuable tool to dissect autophagy processes and the role of autophagy during different biological processes in plants. PMID:24379391

  18. Anti-trypanosomal activity of non-peptidic nitrile-based cysteine protease inhibitors.

    Science.gov (United States)

    Burtoloso, Antonio C B; de Albuquerque, Sérgio; Furber, Mark; Gomes, Juliana C; Gonçalez, Cristiana; Kenny, Peter W; Leitão, Andrei; Montanari, Carlos A; Quilles, José Carlos; Ribeiro, Jean F R; Rocha, Josmar R

    2017-02-01

    The cysteine protease cruzipain is considered to be a validated target for therapeutic intervention in the treatment of Chagas disease. Anti-trypanosomal activity against the CL Brener strain of T. cruzi was observed in the 0.1 μM to 1 μM range for three nitrile-based cysteine protease inhibitors based on two scaffolds known to be associated with cathepsin K inhibition. The two compounds showing the greatest potency against the trypanosome were characterized by EC50 values (0.12 μM and 0.25 μM) that were an order of magnitude lower than the corresponding Ki values measured against cruzain, a recombinant form of cruzipain, in an enzyme inhibition assay. This implies that the anti-trypanosomal activity of these two compounds may not be explained only by the inhibition of the cruzain enzyme, thereby triggering a putative polypharmacological profile towards cysteine proteases.

  19. Optical Absorption and Electric Resistivity of an l-Cysteine Film

    Science.gov (United States)

    Kamada, Masao; Hideshima, Takuya; Azuma, Junpei; Yamamoto, Isamu; Imamura, Masaki; Takahashi, Kazutoshi

    2016-12-01

    The optical and electric properties of an l-cysteine film have been investigated to understand its applicability to bioelectronics. The fundamental absorption is the allowed transition having the threshold at 5.8 eV and the absorption is due to the charge-transfer type transition from sulfur-3sp to oxygen-2p and/or carbon-2p states, while absorptions more than 9 eV can be explained with intra-atomic transitions in the functional groups. The electric resistivity is 2.0 × 104 Ω m at room temperature and increases as the sample temperature decreases. The results indicate that the l-cysteine film is a p-type semiconductor showing the hole conduction caused by the sulfur-3sp occupied states and unknown impurity or defect states as acceptors. The electron affinity of the l-cysteine film is derived as ≦-0.3 eV.

  20. Influence of cysteine and selenodicysteine on the uptake of zinc by Chlorella vulgaris Beijerinck

    International Nuclear Information System (INIS)

    Czauderna, M.; Samochocka, K.

    1982-01-01

    The uptake of zinc labelled with radioactive 65 Zn in the presence of cysteine and selenodicysteine by Chlorella vulgaris was examined. The concentration of zinc ions in the medium was 20 mg per 1. The uptake yield was found to be enhanced by selenodicysteine. At concentration of 10 - 7 -10 - 6 M the growth rate of Chlorella vulgaris was accelerated by the latter, provided that the specific activity of 65 Zn was 3.7 MBq/1. At this specific zinc activity cysteine increased the uptake yield during the initial 50 h of the incubation process. At specific 65 Zn-activity of 55.5 MBq/1 selenodicysteine and cysteine only slightly influenced the zinc uptake by Chlorella vulgaris. No increment in the biomass was observed at this specific zinc radioactivity. (author)

  1. L-Cysteine Capped CdSe Quantum Dots Synthesized by Photochemical Route.

    Science.gov (United States)

    Singh, Avinash; Kunwar, Amit; Rath, M C

    2018-05-01

    L-cysteine capped CdSe quantum dots were synthesized via photochemical route in aqueous solution under UV photo-irradiation. The as grown CdSe quantum dots exhibit broad fluorescence at room temperature. The CdSe quantum dots were found to be formed only through the reactions of the precursors, i.e., Cd(NH3)2+4 and SeSO2-3 with the photochemically generated 1-hydroxy-2-propyl radicals, (CH3)2COH radicals, which are formed through the process of H atom abstraction by the photoexcited acetone from 2-propanol. L-Cysteine was found to act as a suitable capping agent for the CdSe quantum dots and increases their biocompatability. Cytotoxicty effects of these quantum dots were evaluated in Chinese Hamster Ovary (CHO) epithelial cells, indicated a significant lower level for the L-cysteine capped CdSe quantum dots as compare to the bare ones.

  2. Reduction of mercury from mackerel fillet using combined solution of cysteine, EDTA, and sodium chloride.

    Science.gov (United States)

    Hajeb, P; Jinap, S

    2012-06-13

    An acidic solution containing mercury chelating agents to eliminate mercury in raw fish (mackerel) fillet was developed. The solution contained hydrochloric acid, sodium hydroxide, cysteine, EDTA, and NaCl. The optimum conditions for mercury reduction were achieved using response surface methodology (RSM) at cysteine concentration of 1.25%, EDTA of 275 mg/L, NaCl of 0.5%, pH of 3.75, and exposure time of 18 min. The optimized conditions produced a solution which can remove up to 91% mercury from raw fish fillet. Cysteine and EDTA were identified as potential chelating agents with the greatest potential for use. The solution can be employed in fish industries to reduce mercury in highly contaminated fish.

  3. Biological roles of cysteine proteinases in the pathogenesis of Trichomonas vaginalis

    Science.gov (United States)

    Hernández, Hilda M.; Marcet, Ricardo; Sarracent, Jorge

    2014-01-01

    Human trichomonosis, infection with Trichomonas vaginalis, is the most common non-viral sexually transmitted disease in the world. The host-parasite interaction and pathophysiological processes of trichomonosis remain incompletely understood. This review focuses on the advancements reached in the area of the pathogenesis of T. vaginalis, especially in the role of the cysteine proteinases. It highlights various approaches made in this field and lists a group of trichomonad cysteine proteinases involved in diverse processes such as invasion of the mucous layer, cytoadherence, cytotoxicity, cytoskeleton disruption of red blood cells, hemolysis, and evasion of the host immune response. A better understanding of the biological roles of cysteine proteinases in the pathogenesis of this parasite could be used in the identification of new chemotherapeutic targets. An additional advantage could be the development of a vaccine in order to reduce transmission of T. vaginalis. PMID:25348828

  4. Thermo-Kinetic Investigation of Comparative Ligand Effect on Cysteine Iron Redox Reaction

    Directory of Open Access Journals (Sweden)

    Masood Ahmad Rizvi

    2015-03-01

    Full Text Available Transition metal ions in their free state bring unwanted biological oxidations generating oxidative stress. The ligand modulated redox potential can be indispensable in prevention of such oxidative stress by blocking the redundant bio-redox reactions. In this study we investigated the comparative ligand effect on the thermo-kinetic aspects of biologically important cysteine iron (III redox reaction using spectrophotometric and potentiometric methods. The results were corroborated with the complexation effect on redox potential of iron(III-iron(II redox couple. The selected ligands were found to increase the rate of cysteine iron (III redox reaction in proportion to their stability of iron (II complex (EDTA < terpy < bipy < phen. A kinetic profile and the catalytic role of copper (II ions by means of redox shuttle mechanism for the cysteine iron (III redox reaction in presence of 1,10-phenanthroline (phen ligand is also reported.

  5. S-Substituted cysteine derivatives and thiosulfinate formation in Petiveria alliacea-part II.

    Science.gov (United States)

    Kubec, Roman; Kim, Seokwon; Musah, Rabi A

    2002-11-01

    Three cysteine derivatives, (R)-S-(2-hydroxyethyl)cysteine, together with (R(S)R(C))- and (S(S)R(C))-S-(2-hydroxyethyl)cysteine sulfoxides, have been isolated from the roots of Petiveria alliacea. Furthermore, three additional amino acids, S-methyl-, S-ethyl-, and S-propylcysteine derivatives, were detected. They were present only in trace amounts (<3 microg g(-1) fr. wt), precluding determination of their absolute configurations and oxidation states. In addition, four thiosulfinates, S-(2-hydroxyethyl) (2-hydroxyethane)-, S-(2-hydroxyethyl) phenylmethane-, S-benzyl (2-hydroxyethane)- and S-benzyl phenylmethanethiosulfinates, have been found in a homogenate of the roots. The formation pathways of various benzyl/phenyl-containing compounds previously found in the plant were also discussed.

  6. Ethics of conservation triage

    Directory of Open Access Journals (Sweden)

    Kerrie A Wilson

    2016-09-01

    Full Text Available Conservation triage seems to be at a stalemate between those who accept triage based on utilitarian rationalization, and those that reject it based on a number of ethical principles. We argue that without considered attention to the ethics of conservation triage we risk further polarization in the field of conservation. We draw lessons from the medical sector, where triage is more intuitive and acceptable, and also from disaster planning, to help navigate the challenges that triage entails for conservation science, practice, and policy. We clarify the consequentialist, deontological, and virtue ethical stances that influence the level of acceptance of triage. We emphasize the ethical dimensions of conservation triage in principle and in practice, particularly in the context of stakeholder diversity, a wide range of possible objectives and actions, broader institutions, and significant uncertainties. A focus on a more diverse set of ethics, more considered choice of triage as a conservation tool, open communication of triage objectives and protocols, greater consideration of risk preferences, and regular review and adaptation of triage protocols is required for conservation triage to become more acceptable among diverse conservation practitioners, institutions, and the general public. Accepting conservation triage as fundamentally an ethical problem would foster more open dialogue and constructive debate about the role of conservation triage in a wider system of care.

  7. The s48/45 six-cysteine proteins: mediators of interaction throughout the Plasmodium life cycle.

    Science.gov (United States)

    Arredondo, Silvia A; Kappe, Stefan H I

    2017-06-01

    During their life cycle Plasmodium parasites rely upon an arsenal of proteins that establish key interactions with the host and vector, and between the parasite sexual stages, with the purpose of ensuring infection, reproduction and proliferation. Among these is a group of secreted or membrane-anchored proteins known as the six-cysteine (6-cys) family. This is a small but important family with only 14 members thus far identified, each stage-specifically expressed during the parasite life cycle. 6-cys proteins often localise at the parasite surface or interface with the host and vector, and are conserved in different Plasmodium species. The unifying feature of the family is the s48/45 domain, presumably involved in adhesion and structurally related to Ephrins, the ligands of Eph receptors. The most prominent s48/45 members are currently under functional investigation and are being pursued as vaccine candidates. In this review, we examine what is known about the 6-cys family, their structure and function, and discuss future research directions. Copyright © 2016 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

  8. The proteins of Fusobacterium spp. involved in hydrogen sulfide production from L-cysteine.

    Science.gov (United States)

    Basic, Amina; Blomqvist, Madeleine; Dahlén, Gunnar; Svensäter, Gunnel

    2017-03-14

    Hydrogen sulfide (H 2 S) is a toxic foul-smelling gas produced by subgingival biofilms in patients with periodontal disease and is suggested to be part of the pathogenesis of the disease. We studied the H 2 S-producing protein expression of bacterial strains associated with periodontal disease. Further, we examined the effect of a cysteine-rich growth environment on the synthesis of intracellular enzymes in F. nucleatum polymorphum ATCC 10953. The proteins were subjected to one-dimensional (1DE) and two-dimensional (2DE) gel electrophoresis An in-gel activity assay was used to detect the H 2 S-producing enzymes; Sulfide from H 2 S, produced by the enzymes in the gel, reacted with bismuth forming bismuth sulfide, illustrated as brown bands (1D) or spots (2D) in the gel. The discovered proteins were identified with liquid chromatography - tandem mass spectrometry (LC-MS/MS). Cysteine synthase and proteins involved in the production of the coenzyme pyridoxal 5'phosphate (that catalyzes the production of H 2 S) were frequently found among the discovered enzymes. Interestingly, a higher expression of H 2 S-producing enzymes was detected from bacteria incubated without cysteine prior to the experiment. Numerous enzymes, identified as cysteine synthase, were involved in the production of H 2 S from cysteine and the expression varied among Fusobacterium spp. and strains. No enzymes were detected with the in-gel activity assay among the other periodontitis-associated bacteria tested. The expression of the H 2 S-producing enzymes was dependent on environmental conditions such as cysteine concentration and pH but less dependent on the presence of serum and hemin.

  9. An Assay Study of Molecular Recognition of Amino Acids in Water: Covalent Imprinting of Cysteine

    DEFF Research Database (Denmark)

    Burri, Harsha Vardhan Reddy; Yu, Donghong

    2015-01-01

    A novel synthetic N-(9-fluorenyl methoxy carbonyl)-L-Cysteine (Fmoc-Cys(SH)-OH) receptor was pre- pared by co-polymerizing (9-fluorenyl methoxy carbonyl)-S-(1-propene-2-thiol)-L-Cysteine (Fmoc-Cys(SCH2CHCH2)-OH) and a non-imprinted polymer prepared from 1-propene-1-thiol photo-chemically 15 h...... at room temperature and additional 3 h thermally at 80℃. Subsequently, disulfides were reduced with lithium aluminum hydride (LiAlH4) from imprinted polymers. The imprinted polymers selectively recognized Fmoc-Cys(SH)-OH with high binding constants in aqueous and protic solvents by thiol...

  10. A simple synthesis of L-[35S]cysteine sulfinic acid

    International Nuclear Information System (INIS)

    Spears, R.M.; Martin, D.L.

    1981-01-01

    The synthesis of L-[ 35 S]cysteine sulfinic acid (L-2-amino-3-[ 35 S]sulfino-propanoic acid) in 65% yield from S-[ 35 S]cystine is described. The procedure was designed for use with milligram quantities of starting material and requires no purification of intermediates. L-[ 35 S]Cystine was converted first to its thiosulfonate. Subsequent reaction of the thiosulfonate with ammonium hydroxide generated L-[ 35 S]cysteine sulfinic acid and L-[ 35 S]cystine as the major products. The L-[ 35 S]cystine was recovered and reprocessed thereby increasing the yield. (author)

  11. Parameters optimization defined by statistical analysis for cysteine-dextran radiolabeling with technetium tricarbonyl core.

    Science.gov (United States)

    Núñez, Eutimio Gustavo Fernández; Faintuch, Bluma Linkowski; Teodoro, Rodrigo; Wiecek, Danielle Pereira; da Silva, Natanael Gomes; Papadopoulos, Minas; Pelecanou, Maria; Pirmettis, Ioannis; de Oliveira Filho, Renato Santos; Duatti, Adriano; Pasqualini, Roberto

    2011-04-01

    The objective of this study was the development of a statistical approach for radiolabeling optimization of cysteine-dextran conjugates with Tc-99m tricarbonyl core. This strategy has been applied to the labeling of 2-propylene-S-cysteine-dextran in the attempt to prepare a new class of tracers for sentinel lymph node detection, and can be extended to other radiopharmaceuticals for different targets. The statistical routine was based on three-level factorial design. Best labeling conditions were achieved. The specific activity reached was 5 MBq/μg. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  12. Parameters optimization defined by statistical analysis for cysteine-dextran radiolabeling with technetium tricarbonyl core

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Nunez, Eutimio Gustavo, E-mail: eutimiocu@yahoo.co [Radiopharmacy Center, Institute of Energetic and Nuclear Research, Sao Paulo, SP 05508-000 (Brazil); Linkowski Faintuch, Bluma; Teodoro, Rodrigo; Pereira Wiecek, Danielle; Gomes da Silva, Natanael [Radiopharmacy Center, Institute of Energetic and Nuclear Research, Sao Paulo, SP 05508-000 (Brazil); Papadopoulos, Minas [Institute of Radioisotopes, Radiodiagnostic Products, National Center for Scientific Research ' Demokritos' , Athens (Greece); Pelecanou, Maria [Institute of Biology, National Center for Scientific Research ' Demokritos' , Athens (Greece); Pirmettis, Ioannis [Institute of Radioisotopes, Radiodiagnostic Products, National Center for Scientific Research ' Demokritos' , Athens (Greece); Santos Oliveira Filho, Renato de [Faculty of Medicine, Federal University of Sao Paulo, SP (Brazil); Duatti, Adriano [Department of Radiological Sciences, University of Ferrara, Ferrara (Italy); Pasqualini, Roberto [CIS Bio International, Gif sur Yvette (France)

    2011-04-15

    The objective of this study was the development of a statistical approach for radiolabeling optimization of cysteine-dextran conjugates with Tc-99m tricarbonyl core. This strategy has been applied to the labeling of 2-propylene-S-cysteine-dextran in the attempt to prepare a new class of tracers for sentinel lymph node detection, and can be extended to other radiopharmaceuticals for different targets. The statistical routine was based on three-level factorial design. Best labeling conditions were achieved. The specific activity reached was 5 MBq/{mu}g.

  13. Formation of Hg(II) Tetrathiolate Complexes with Cysteine at Neutral pH.

    Science.gov (United States)

    Warner, Thomas; Jalilehvand, Farideh

    2016-04-01

    Mercury(II) ions precipitate from aqueous cysteine (H 2 Cys) solutions containing H 2 Cys/Hg(II) mole ratio ≥ 2.0 as Hg( S -HCys) 2 . In absence of additional cysteine, the precipitate dissolves at pH ~12 with the [Hg( S,N -Cys) 2 ] 2- complex dominating. With excess cysteine (H 2 Cys/Hg(II) mole ratio ≥ 4.0), higher complexes form and the precipitate dissolves at lower pH values. Previously, we found that tetrathiolate [Hg( S -Cys) 4 ] 6- complexes form at pH = 11.0; in this work we extend the investigation to pH values of physiological interest. We examined two series of Hg(II)-cysteine solutions in which C Hg(II) varied between 8 - 9 mM and 80 - 100 mM, respectively, with H 2 Cys/Hg(II) mole ratios from 4 to ~20. The solutions were prepared in the pH range 7.1 - 8.8, at the pH at which the initial Hg( S -HCys) 2 precipitate dissolved. The variations in the Hg(II) speciation were followed by 199 Hg NMR, X-ray absorption and Raman spectroscopic techniques. Our results show that in the dilute solutions ( C Hg(II) = 8 - 9 mM), mixtures of di-, tri- (major) and tetrathiolate complexes exist at moderate cysteine excess ( C H2Cys ~ 0.16 M) at pH 7.1. In the more concentrated solutions ( C Hg(II) = 80 - 100 mM) with high cysteine excess ( C H2Cys > 0.9 M), tetrathiolate [Hg( S -cysteinate) 4 ] m -6 ( m = 0 - 4) complexes dominate in the pH range 7.3 - 7.8, with lower charge than for the [Hg( S -Cys) 4 ] 6- complex due to protonation of some ( m ) of the amino groups of the coordinated cysteine ligands. The results of this investigation could provide a key to the mechanism of biosorption and accumulation of Hg(II) ions in biological / environmental systems.

  14. Micronutrients, N-Acetyl Cysteine, Probiotics and Prebiotics, a Review of Effectiveness in Reducing HIV Progression

    Science.gov (United States)

    Hummelen, Ruben; Hemsworth, Jaimie; Reid, Gregor

    2010-01-01

    Low serum concentrations of micronutrients, intestinal abnormalities, and an inflammatory state have been associated with HIV progression. These may be ameliorated by micronutrients, N-acetyl cysteine, probiotics, and prebiotics. This review aims to integrate the evidence from clinical trials of these interventions on the progression of HIV. Vitamin B, C, E, and folic acid have been shown to delay the progression of HIV. Supplementation with selenium, N-acetyl cysteine, probiotics, and prebiotics has considerable potential, but the evidence needs to be further substantiated. Vitamin A, iron, and zinc have been associated with adverse effects and caution is warranted for their use. PMID:22254046

  15. Labeling of human serum albumin with 105Rh-cysteine complexes

    International Nuclear Information System (INIS)

    Lo, J.M.; Pillai, M.R.A.; John, C.S.; Troutner, D.E.

    1990-01-01

    The conjugation of a complex formed by reacting RhCl 3 with cysteine to human serum albumin has been investigated. Approximately 50% of the rhodium (labelled with 105 Rh) was converted to the complex. Conjugation of the complex to HSA via the ECDI method resulted in yields of ∼ 40% of the total rhodium or ∼ 80% of the Rh-cysteine complex. No conjugation was observed in the absence of the ECDI. At approximately equal molar concentrations of rhodium and HSA, an average of ∼ 0.4 rhodium atoms per HSA molecule was achieved. (author)

  16. Chemoselective synthesis and analysis of naturally occurring phosphorylated cysteine peptides

    Science.gov (United States)

    Bertran-Vicente, Jordi; Penkert, Martin; Nieto-Garcia, Olaia; Jeckelmann, Jean-Marc; Schmieder, Peter; Krause, Eberhard; Hackenberger, Christian P. R.

    2016-09-01

    In contrast to protein O-phosphorylation, studying the function of the less frequent N- and S-phosphorylation events have lagged behind because they have chemical features that prevent their manipulation through standard synthetic and analytical methods. Here we report on the development of a chemoselective synthetic method to phosphorylate Cys side-chains in unprotected peptides. This approach makes use of a reaction between nucleophilic phosphites and electrophilic disulfides accessible by standard methods. We achieve the stereochemically defined phosphorylation of a Cys residue and verify the modification using electron-transfer higher-energy dissociation (EThcD) mass spectrometry. To demonstrate the use of the approach in resolving biological questions, we identify an endogenous Cys phosphorylation site in IICBGlc, which is known to be involved in the carbohydrate uptake from the bacterial phosphotransferase system (PTS). This new chemical and analytical approach finally allows further investigating the functions and significance of Cys phosphorylation in a wide range of crucial cellular processes.

  17. Identification of the bacteria-binding peptide domain on salivary agglutinin (gp-340/DMBT1), a member of the scavenger receptor cysteine-rich superfamily

    DEFF Research Database (Denmark)

    Bikker, Floris J; Ligtenberg, Antoon J M; Nazmi, Kamran

    2002-01-01

    Salivary agglutinin is encoded by DMBT1 and identical to gp-340, a member of the scavenger receptor cysteine-rich (SRCR) superfamily. Salivary agglutinin/DMBT1 is known for its Streptococcus mutans agglutinating properties. This 300-400 kDa glycoprotein is composed of conserved peptide motifs: 14...... containing exclusively SRCR and SID domains that binds to S. mutans. To define more closely the S. mutans-binding domain, consensus-based peptides of the SRCR domains and SIDs were designed and synthesized. Only one of the SRCR peptides, designated SRCRP2, and none of the SID peptides bound to S. mutans....... Strikingly, this peptide was also able to induce agglutination of S. mutans and a number of other bacteria. The repeated presence of this peptide in the native molecule endows agglutinin/DMBT1 with a general bacterial binding feature with a multivalent character. Moreover, our studies demonstrate...

  18. Post meningitis subdural hygroma: anatomical and functional evaluation with 99mTc-ethylene cysteine dimer single photon emission tomography/computed tomography

    International Nuclear Information System (INIS)

    Sharma, Punit; Mishra, Ajiv; Arora, Geetanjali; Tripathi, Madhavi; Bal, Chandrasekhar; Kumar, Rakesh

    2013-01-01

    Subdural hygroma is the collection of cerebrospinal fluid in the subdural space. Most often these resolve spontaneously. However, in cases with neurological complications surgical drainage may be needed. We here, present the case of an 8-year-old boy with post meningitis subdural hygroma. 99m Tc-ethylene cysteine dimer ( 99m Tc-ECD) hybrid single photon emission tomography/computed tomography (SPECT/CT) carried out in this patient, demonstrated the subdural hygroma as well as the associated cerebral hypoperfusion. If 99m Tc-ECD SPECT/CT is integrated into management of these patients, it can help in decision making with respect to conservative versus surgical management. (author)

  19. Evaluation of residue-residue contact predictions in CASP9

    KAUST Repository

    Monastyrskyy, Bohdan; Fidelis, Krzysztof; Tramontano, Anna; Kryshtafovych, Andriy

    2011-01-01

    This work presents the results of the assessment of the intramolecular residue-residue contact predictions submitted to CASP9. The methodology for the assessment does not differ from that used in previous CASPs, with two basic evaluation measures

  20. Deorphanization and target validation of cross-tick species conserved novel Amblyomma americanum tick saliva protein.

    Science.gov (United States)

    Mulenga, Albert; Kim, Tae Kwon; Ibelli, Adriana Mércia Guaratini

    2013-05-01

    We previously identified a cross-tick species conserved tick feeding stimuli responsive Amblyomma americanum (Aam) AV422 gene. This study demonstrates that AamAV422 belongs to a novel group of arthropod proteins that is characterized by 14 cysteine amino acid residues: C(23)-X7/9-C(33)-X23/24-C(58)-X8-C(67)-X7-C(75)-X23-C(99)-X15-C(115)-X10-C(126)-X24/25/33-C(150)C(151)-X7-C(159)-X8-C(168)-X23/24-C(192)-X9/10-C(202) predicted to form seven disulfide bonds. We show that AamAV422 protein is a ubiquitously expressed protein that is injected into the host within the first 24h of the tick attaching onto the host as revealed by Western blotting analyses of recombinant (r)AamAV422, tick saliva and dissected tick organ protein extracts using antibodies to 24 and 48 h tick saliva proteins. Native AamAV422 is apparently involved with mediating tick anti-hemostasis and anti-complement functions in that rAamAV422 delayed plasma clotting time in a dose responsive manner by up to ≈ 160 s, prevented platelet aggregation by up to ≈ 16% and caused ≈ 24% reduction in production of terminal complement complexes. Target validation analysis revealed that rAamAV422 is a potential candidate for a cocktail or multivalent tick vaccine preparation in that RNA interference (RNAi)-mediated silencing of AamAV422 mRNA caused a statistically significant (≈ 44%) reduction in tick engorgement weights, which is proxy for amounts of ingested blood. We speculate that AamAV422 is a potential target antigen for development of the highly desired universal tick vaccine in that consistent with high conservation among ticks, antibodies to 24h Ixodes scapularis tick saliva proteins specifically bound rAamAV422. We discuss data in this study in the context of advancing the biology of tick feeding physiology and discovery of potential target antigens for tick vaccine development. Copyright © 2013 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  1. Conservation: Toward firmer ground

    Science.gov (United States)

    1975-01-01

    The following aspects of energy conservation were discussed: conservation history and goals, conservation modes, conservation accounting-criteria, and a method to overcome obstacles. The conservation modes tested fall into one of the following categories: reduced energy consumption, increased efficiency of energy utilization, or substitution of one or more forms of energy for another which is in shorter supply or in some sense thought to be of more value. The conservation accounting criteria include net energy reduction, economic, and technical criteria. A method to overcome obstacles includes (approaches such as: direct personal impact (life style, income, security, aspiration), an element of crisis, large scale involvement of environmental, safety, and health issues, connections to big government, big business, big politics, involvement of known and speculative science and technology, appeal to moral and ethical standards, the transient nature of opportunities to correct the system.

  2. Econometric modelling of conservation

    International Nuclear Information System (INIS)

    Parker, J.C.; Seal, D.J.

    1990-01-01

    The issue of energy conservation in general, and conservation in the natural gas markets in particular, has recently had a much lower profile than in the past, when energy prices were significantly higher and energy costs composed a much larger proportion of industrial operating costs than today. The recent downward trend in energy prices has diverted attention away from this issue. In the face of expected significant real price increases, increasing pressure from environmental groups, and directives on the part of regulator authorities, conservation is once again becoming a topic of consideration in the energy industry. From the point of view of gas demand forecasting, conservation has received too little attention. The intentions of this paper are to establish the need for forecasting conservation in the natural gas utility sector, and to construct a model of industrial demand which incorporates conservation and is appropriate for use as a forecasting tool

  3. Sharing Residual Liability

    DEFF Research Database (Denmark)

    Carbonara, Emanuela; Guerra, Alice; Parisi, Francesco

    2016-01-01

    Economic models of tort law evaluate the efficiency of liability rules in terms of care and activity levels. A liability regime is optimal when it creates incentives to maximize the value of risky activities net of accident and precaution costs. The allocation of primary and residual liability...... for policy makers and courts in awarding damages in a large number of real-world accident cases....

  4. Dealing with the sulfur part of cysteine: four enzymatic steps degrade l-cysteine to pyruvate and thiosulfate in Arabidopsis mitochondria.

    Science.gov (United States)

    Höfler, Saskia; Lorenz, Christin; Busch, Tjorven; Brinkkötter, Mascha; Tohge, Takayuki; Fernie, Alisdair R; Braun, Hans-Peter; Hildebrandt, Tatjana M

    2016-07-01

    Amino acid catabolism is essential for adjusting pool sizes of free amino acids and takes part in energy production as well as nutrient remobilization. The carbon skeletons are generally converted to precursors or intermediates of the tricarboxylic acid cycle. In the case of cysteine, the reduced sulfur derived from the thiol group also has to be oxidized in order to prevent accumulation to toxic concentrations. Here we present a mitochondrial sulfur catabolic pathway catalyzing the complete oxidation of l-cysteine to pyruvate and thiosulfate. After transamination to 3-mercaptopyruvate, the sulfhydryl group from l-cysteine is transferred to glutathione by sulfurtransferase 1 and oxidized to sulfite by the sulfur dioxygenase ETHE1. Sulfite is then converted to thiosulfate by addition of a second persulfide group by sulfurtransferase 1. This pathway is most relevant during early embryo development and for vegetative growth under light-limiting conditions. Characterization of a double mutant produced from Arabidopsis thaliana T-DNA insertion lines for ETHE1 and sulfurtransferase 1 revealed that an intermediate of the ETHE1 dependent pathway, most likely a persulfide, interferes with amino acid catabolism and induces early senescence. © 2016 Scandinavian Plant Physiology Society.

  5. Exercise induced upregulation of glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase modifier subunit gene expression in Thoroughbred horses

    Directory of Open Access Journals (Sweden)

    Jeong-Woong Park

    2017-05-01

    Full Text Available Objective This study was performed to reveal the molecular structure and expression patterns of horse glutamate-cysteine ligase catalytic subunit (GCLC and glutamate-cysteine ligase modifier subunit (GCLM genes whose products form glutamate cysteine ligase, which were identified as differentially expressed genes in the previous study. Methods We performed bioinformatics analyses, and gene expression assay with quantitative polymerase chain reaction (qPCR for horse GCLC and GCLM genes in muscle and blood leukocytes of Thoroughbred horses Results Expression of GCLC showed the same pattern in both blood and muscle tissues after exercise. Expression of GCLC increased in the muscle and blood of Thoroughbreds, suggesting a tissue-specific regulatory mechanism for the expression of GCLC. In addition, expression of the GCLM gene increased after exercise in both the blood and muscle of Thoroughbreds. Conclusion We established the expression patterns of GCLC and GCLM in the skeletal muscle and blood of Thoroughbred horses in response to exercise. Further study is now warranted to uncover the functional importance of these genes in exercise and recovery in racehorses.

  6. Handbook on energy conservation

    International Nuclear Information System (INIS)

    1989-12-01

    This book shows energy situation in recent years, which includes reserves of energy resource in the world, crude oil production records in OPEC and non OPEC, supply and demand of energy in important developed countries, prospect of supply and demand of energy and current situation of energy conservation in developed countries. It also deals with energy situation in Korea reporting natural resources status, energy conservation policy, measurement for alternative energy, energy management of Korea, investment in equipment and public education for energy conservation.

  7. An unusual cysteine VL87 affects the antibody fragment conformations without interfering with the disulfide bond formation.

    Science.gov (United States)

    Attallah, Carolina; Aguilar, María Fernanda; Garay, A Sergio; Herrera, Fernando E; Etcheverrigaray, Marina; Oggero, Marcos; Rodrigues, Daniel E

    2017-10-01

    The Cys residues are almost perfectly conserved in all antibodies. They contribute significantly to the antibody fragment stability. The relevance of two natural contiguous Cys residues of an anti-recombinant human-follicle stimulation hormone (rhFSH) in a format of single-chain variable fragment (scFv) was studied. This scFv contains 5 Cys residues: V H 22 and V H 92 in the variable heavy chain (V H ) and V L 23, V L 87 and V L 88 in the variable light chain (V L ). The influence of two unusual contiguous Cys at positions V L 87 and V L 88 was studied by considering the wild type fragment and mutant variants: V L -C88S, V L -C87S, V L -C87Y. The analysis was carried out using antigen-binding ability measurement by indirect specific ELISA and a detailed molecular modeling that comprises homology methods, long molecular dynamics simulations and docking. We found that V L -C87 affected the antibody fragment stability without interfering with the disulfide bond formation. The effect of mutating the V L -C87 by a usual residue