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Sample records for non-ribosomal peptide synthesis

  1. Predicted class-I aminoacyl tRNA synthetase-like proteins in non-ribosomal peptide synthesis

    Directory of Open Access Journals (Sweden)

    Iyer Lakshminarayan M

    2010-08-01

    Full Text Available Abstract Background Recent studies point to a great diversity of non-ribosomal peptide synthesis systems with major roles in amino acid and co-factor biosynthesis, secondary metabolism, and post-translational modifications of proteins by peptide tags. The least studied of these systems are those utilizing tRNAs or aminoacyl-tRNA synthetases (AAtRS in non-ribosomal peptide ligation. Results Here we describe novel examples of AAtRS related proteins that are likely to be involved in the synthesis of widely distributed peptide-derived metabolites. Using sensitive sequence profile methods we show that the cyclodipeptide synthases (CDPSs are members of the HUP class of Rossmannoid domains and are likely to be highly derived versions of the class-I AAtRS catalytic domains. We also identify the first eukaryotic CDPSs in fungi and in animals; they might be involved in immune response in the latter organisms. We also identify a paralogous version of the methionyl-tRNA synthetase, which is widespread in bacteria, and present evidence using contextual information that it might function independently of protein synthesis as a peptide ligase in the formation of a peptide- derived secondary metabolite. This metabolite is likely to be heavily modified through multiple reactions catalyzed by a metal-binding cupin domain and a lysine N6 monooxygenase that are strictly associated with this paralogous methionyl-tRNA synthetase (MtRS. We further identify an analogous system wherein the MtRS has been replaced by more typical peptide ligases with the ATP-grasp or modular condensation-domains. Conclusions The prevalence of these predicted biosynthetic pathways in phylogenetically distant, pathogenic or symbiotic bacteria suggests that metabolites synthesized by them might participate in interactions with the host. More generally, these findings point to a complete spectrum of recruitment of AAtRS to various non-ribosomal biosynthetic pathways, ranging from the

  2. Non-ribosomal peptide synthetases

    Indian Academy of Sciences (India)

    2017-01-19

    Jan 19, 2017 ... 2009). In other words, the characterization of A-domains can help in the structure prediction of the NRP, encoded by a cryptic NRPS BGC. A-domain specificity can also be altered for the synthesis of unnatural products with novel physicochemical properties over the original natural product (Hur et al. 2012).

  3. Non-ribosomal peptide synthetases: Identifying the cryptic gene ...

    Indian Academy of Sciences (India)

    2017-01-19

    Jan 19, 2017 ... Non-ribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs) present in bacteria and fungi are the major multi-modular enzyme complexes which synthesize secondary metabolites like the pharmacologically impor- tant antibiotics and siderophores. Each of the multiple modules of an ...

  4. Non-ribosomal peptide synthetases: Identifying the cryptic gene ...

    Indian Academy of Sciences (India)

    Non-ribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs) present in bacteria and fungi are themajor multi-modular enzyme complexes which synthesize secondary metabolites like the pharmacologically importantantibiotics and siderophores. Each of the multiple modules of an NRPS activates a ...

  5. Cyclization of polyketides and non-ribosomal peptides on and off their assembly lines.

    Science.gov (United States)

    Pang, Bo; Wang, Min; Liu, Wen

    2016-02-01

    Modular polyketide synthases (PKSs) and non-ribosomal peptide synthetases (NRPSs) are multifunctional megaenzymes that serve as templates to program the assembly of short carboxylic acids and amino acids in a primarily co-linear manner. The variation, combination, permutation and evolution of their functional units (e.g., modules, domains and proteins) along with their association with external enzymes have resulted in the generation of numerous versions of templates, the roles of which have not been fully recognized in the structural diversification of polyketides, non-ribosomal peptides and their hybrids present in nature. In this Highlight, we focus on the assembly-line enzymology and associated chemistry by providing examples of some newly characterized cyclization reactions that occur on and off the assembly lines during and after chain elongation for the purpose of elucidating the template effects of PKSs and NRPSs. A fundamental understanding of the underlying biosynthetic logic would facilitate the elucidation of chemical information contained within the PKS or NRPS templates and benefit the development of strategies for genome mining, biosynthesis-inspired chemical synthesis and combinatorial biosynthesis.

  6. De novo design and engineering of non-ribosomal peptide synthetases

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    Bozhüyük, Kenan A. J.; Fleischhacker, Florian; Linck, Annabell; Wesche, Frank; Tietze, Andreas; Niesert, Claus-Peter; Bode, Helge B.

    2018-03-01

    Peptides derived from non-ribosomal peptide synthetases (NRPSs) represent an important class of pharmaceutically relevant drugs. Methods to generate novel non-ribosomal peptides or to modify peptide natural products in an easy and predictable way are therefore of great interest. However, although the overall modular structure of NRPSs suggests the possibility of adjusting domain specificity and selectivity, only a few examples have been reported and these usually show a severe drop in production titre. Here we report a new strategy for the modification of NRPSs that uses defined exchange units (XUs) and not modules as functional units. XUs are fused at specific positions that connect the condensation and adenylation domains and respect the original specificity of the downstream module to enable the production of the desired peptides. We also present the use of internal condensation domains as an alternative to other peptide-chain-releasing domains for the production of cyclic peptides.

  7. Computational discovery of specificity-conferring sites in non-ribosomal peptide synthetases

    DEFF Research Database (Denmark)

    Knudsen, Michael; Søndergaard, Dan Ariel; Tofting-Olesen, Claus

    2016-01-01

    Motivation: By using a class of large modular enzymes known as Non-Ribosomal Peptide Synthetases (NRPS), bacteria and fungi are capable of synthesizing a large variety of secondary metabolites, many of which are bioactive and have potential, pharmaceutical applications as e.g.~antibiotics. There ...

  8. Engineering Biosynthesis of Non-ribosomal Peptides and Polyketides by Directed Evolution.

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    Rui, Zhe; Zhang, Wenjun

    2016-01-01

    Non-ribosomal peptides (NRPs) and polyketides (PKs) play key roles in pharmaceutical industry due to their promising biological activities. The structural complexity of NRPs and PKs, however, creates significant synthetic challenges for producing these natural products and their analogues by purely chemical means. Alternatively, difficult syntheses can be achieved by using biosynthetic enzymes with improved efficiency and altered selectivity that are acquired from directed evolution. Key to the successful directed evolution is the methodology of screening/selection. This review summarizes the screening/selection strategies that have been employed to improve or modify the functions of non-ribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), in the hope of triggering the wide adoption of the directed evolution approaches in the engineered biosynthesis of NRPs and PKs for drug discovery.

  9. Heterologous production of non-ribosomal peptide LLD-ACV in Saccharomyces cerevisiae.

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    Siewers, Verena; Chen, Xiao; Huang, Le; Zhang, Jie; Nielsen, Jens

    2009-11-01

    Non-ribosomal peptides (NRPs) are a diverse family of secondary metabolites with a broad range of biological activities. We started to develop an eukaryotic microbial platform based on the yeast Saccharomyces cerevisiae for heterologous production of NRPs using delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine (ACV) as a model NRP. The Penicillium chrysogenum gene pcbAB encoding ACV synthetase was expressed in S. cerevisiae from a high-copy plasmid together with phosphopantetheinyl transferase (PPTase) encoding genes from Aspergillus nidulans, P. chrysogenum and Bacillus subtilis, and in all the three cases production of ACV was observed. To improve ACV synthesis, several factors were investigated. Codon optimization of the 5' end of pcbAB did not significantly increase ACV production. However, a 30-fold enhancement was achieved by lowering the cultivation temperature from 30 to 20 degrees C. When ACVS and PPTase encoding genes were integrated into the yeast genome, a 6-fold decrease in ACV production was observed indicating that gene copy number was one of the rate-limiting factors for ACV production in yeast.

  10. Non-ribosomal peptides produced by Planktothrix agardhii from Siemianówka Dam Reservoir SDR (northeast Poland).

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    Grabowska, Magdalena; Kobos, Justyna; Toruńska-Sitarz, Anna; Mazur-Marzec, Hanna

    2014-10-01

    Planktothtrix agardhii (Oscillatoriales) is a filamentous cyanobacterium, which frequently forms blooms in shallow, polymictic and eutrophicated waters. This species is also a rich source of unique linear and cyclic peptides. In the current study, the profile of the peptides in samples from the P. agardhii-dominated Siemianówka Dam Reservoir (SDR) (northeast Poland) was analyzed for four subsequent years (2009-2012). The LC-MS/MS analyses revealed the presence of 33 peptides. Twelve of the most abundant ones, including five microcystins, five anabaenopeptins, one aeruginosin and one planktocyclin, were present in all field samples collected during the study. The detection of different peptides in two P. agardhii isolates indicated that the SDR population was composed of several chemotypes, characterized by different peptide patterns. The total concentration of microcystins (MCs) positively correlated with the biomass of P. agardhii. Between subsequent years, the changes in the ratio of the total MCs concentration to the biomass of P. agardhii were noticed, but they were less than threefold. This is the first study on the production of different classes of non-ribosomal peptides by freshwater cyanobacteria in Poland.

  11. Genetic and Functional Analysis of the Biosynthesis of a Non-Ribosomal Peptide Siderophore in Burkholderia xenovorans LB400.

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    María José Vargas-Straube

    Full Text Available B. xenovorans LB400 is a model bacterium for the study of the metabolism of aromatic compounds. The aim of this study was the genomic and functional characterization of a non-ribosomal peptide synthetase containing gene cluster that encodes a siderophore in B. xenovorans LB400. The mba gene cluster from strain LB400 encodes proteins involved in the biosynthesis and transport of a hydroxamate-type siderophore. Strain LB400 has a unique mba gene organization, although mba gene clusters have been observed in diverse Burkholderiales. Bioinformatic analysis revealed the presence of promoters in the mba gene cluster that strongly suggest regulation by the ferric uptake regulator protein (Fur and by the alternative RNA polymerase extracytoplasmic function sigma factor MbaF. Reverse transcriptase PCR analyses showed the expression of iron-regulated transcriptional units mbaFGHIJKL, mbaN, mbaABCE, mbaO, mbaP and mbaD genes under iron limitation. Chrome azurol S (CAS assay strongly suggests that strain LB400 synthesized a siderophore under iron limitation. Mass spectrometry ESI-MS and MALDI-TOF-MS analyses revealed that the siderophore is a non-ribosomal peptide, and forms an iron complex with a molecular mass of 676 Da. Based on bioinformatic prediction, CAS assay and MS analyses, we propose that the siderophore is L-Nδ-hydroxy-Nδ-formylOrn-D-β-hydroxyAsp-L-Ser-L-Nδ-hydroxy-Nδ-formylOrn-1,4-diaminobutane that is closely related to malleobactin-type siderophores reported in B. thailandensis.

  12. Genetic analysis of the biosynthesis of non-ribosomal peptide- and polyketide-like antibiotics, iron uptake and biofilm formation by Bacillus subtilis A1/3.

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    Hofemeister, J; Conrad, B; Adler, B; Hofemeister, B; Feesche, J; Kucheryava, N; Steinborn, G; Franke, P; Grammel, N; Zwintscher, A; Leenders, F; Hitzeroth, G; Vater, J

    2004-11-01

    The Bacillus subtilis strain A1/3 shows exceptionally diverse antibiotic capacities compared to other B. subtilis strains. To analyze this phenomenon, mutants for the putative pantotheinyltransferase gene (pptS), and for several genes involved in non-ribosomal peptide synthesis and polyketide synthesis were constructed and characterized, using bioassays with blood cells, bacterial and fungal cells, and mass spectrometry. Among at least nine distinct bioactive compounds, five antibiotics and one siderophore activity were identified. The anti-fungal and hemolytic activities of strain A1/3 could be eliminated by mutation of the fen and srf genes essential for the synthesis of fengycins and surfactins. Both pptS- and dhb -type mutants were defective in iron uptake, indicating an inability to produce a 2,3-dihydroxybenzoate-type iron siderophore. Transposon mutants in the malonyl CoA transacylase gene resulted in the loss of hemolytic and anti-fungal activities due to the inhibition of bacillomycin L synthesis, and this led to the discovery of bmyLD-LA-LB* genes. In mutants bearing disruption mutations in polyketide (pksM- and/or pksR -like) genes, the biosynthesis of bacillaene and difficidins, respectively, was inactivated and was accompanied by the loss of discrete antibacterial activities. The formation of biofilms (pellicles) was shown to require the production of surfactins, but no other lipopeptides, indicating that surfactins serve specific developmental functions.

  13. Synthetic fermentation of bioactive non-ribosomal peptides without organisms, enzymes or reagents

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    Huang, Yi-Lin; Bode, Jeffrey W.

    2014-10-01

    Microbial fermentation can rapidly provide potent compounds that can be easily screened for biological activity, and the active components can be isolated. Its success in drug discovery has inspired extensive efforts to modulate and control the products. In this Article, we document a ‘synthetic fermentation’ of bioactive, unnatural peptides ‘grown’ from small building blocks in water using amide-forming ligations. No organisms, enzymes or reagents are needed. The sequences, structures and compositions of the products can be modulated by adjusting the building blocks and conditions. No specialized knowledge of organic chemistry or handling of toxic material is required to produce complex organic molecules. The ‘fermentations’ can be conducted in arrays and screened for biological activity without isolation or workup. As a proof-of-concept, about 6,000 unnatural peptides were produced from just 23 building blocks, from which a hepatitis C virus NS3/4A protease inhibitor with a half-maximum inhibitory concentration of 1.0 μM was identified and characterized.

  14. Heterologous production of non-ribosomal peptide LLD-ACV in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Siewers, Verena; Chen, Xiao; Huang, Le

    2009-01-01

    production of ACV was observed. To improve ACV synthesis, several factors were investigated. Codon optimization of the 5′ end of pcbAB did not significantly increase ACV production. However, a 30-fold enhancement was achieved by lowering the cultivation temperature from 30 to 20 °C. When ACVS and PPTase...... encoding genes were integrated into the yeast genome, a 6-fold decrease in ACV production was observed indicating that gene copy number was one of the rate-limiting factors for ACV production in yeast....

  15. Non-ribosomal Peptide Synthases from Pseudomonas aeruginosa Play a Role in Cyclodipeptide Biosynthesis, Quorum-Sensing Regulation, and Root Development in a Plant Host.

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    González, Omar; Ortíz-Castro, Randy; Díaz-Pérez, César; Díaz-Pérez, Alma L; Magaña-Dueñas, Viridiana; López-Bucio, José; Campos-García, Jesús

    2017-04-01

    Diverse molecules mediate cross-kingdom communication between bacteria and their eukaryotic partners and determine pathogenic or symbiotic relationships. N-acyl-L-homoserine lactone-dependent quorum-sensing signaling represses the biosynthesis of bacterial cyclodipeptides (CDPs) that act as auxin signal mimics in the host plant Arabidopsis thaliana. In this work, we performed bioinformatics, biochemical, and plant growth analyses to identify non-ribosomal peptide synthase (NRPS) proteins of Pseudomonas aeruginosa, which are involved in CDP synthesis. A reverse genetics strategy allowed the identification of the genes encoding putative multi-modular-NRPS (MM-NRPS). Mutations in these genes affected the synthesis of the CDPs cyclo(L-Pro-L-Val), cyclo(L-Pro-L-Leu), and cyclo(L-Pro-L-Tyr), while showing wild-type-like levels of virulence factors, such as violacein, elastase, and pyocyanin. When analyzing the bioactivity of purified, naturally produced CDPs, it was found that cyclo(L-Pro-L-Tyr) and cyclo(L-Pro-L-Val) were capable of antagonizing quorum-sensing-LasR (QS-LasR)-dependent signaling in a contrasting manner in the cell-free supernatants of the selected NRPS mutants, which showed QS induction. Using a bacteria-plant interaction system, we further show that the pvdJ, ambB, and pchE P. aeruginosa mutants failed to repress primary root growth, but improved root branching in A. thaliana seedlings. These results indicated that the CDP production in P. aeruginosa depended on the functional MM-NRPS, which influences quorum-sensing of bacteria and plays a role in root architecture remodeling.

  16. The Insect Pathogen Serratia marcescens Db10 Uses a Hybrid Non-Ribosomal Peptide Synthetase-Polyketide Synthase to Produce the Antibiotic Althiomycin

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    Challis, Gregory L.; Stanley-Wall, Nicola R.; Coulthurst, Sarah J.

    2012-01-01

    There is a continuing need to discover new bioactive natural products, such as antibiotics, in genetically-amenable micro-organisms. We observed that the enteric insect pathogen, Serratia marcescens Db10, produced a diffusible compound that inhibited the growth of Bacillis subtilis and Staphyloccocus aureus. Mapping the genetic locus required for this activity revealed a putative natural product biosynthetic gene cluster, further defined to a six-gene operon named alb1–alb6. Bioinformatic analysis of the proteins encoded by alb1–6 predicted a hybrid non-ribosomal peptide synthetase-polyketide synthase (NRPS-PKS) assembly line (Alb4/5/6), tailoring enzymes (Alb2/3) and an export/resistance protein (Alb1), and suggested that the machinery assembled althiomycin or a related molecule. Althiomycin is a ribosome-inhibiting antibiotic whose biosynthetic machinery had been elusive for decades. Chromatographic and spectroscopic analyses confirmed that wild type S. marcescens produced althiomycin and that production was eliminated on disruption of the alb gene cluster. Construction of mutants with in-frame deletions of specific alb genes demonstrated that Alb2–Alb5 were essential for althiomycin production, whereas Alb6 was required for maximal production of the antibiotic. A phosphopantetheinyl transferase enzyme required for althiomycin biosynthesis was also identified. Expression of Alb1, a predicted major facilitator superfamily efflux pump, conferred althiomycin resistance on another, sensitive, strain of S. marcescens. This is the first report of althiomycin production outside of the Myxobacteria or Streptomyces and paves the way for future exploitation of the biosynthetic machinery, since S. marcescens represents a convenient and tractable producing organism. PMID:23028578

  17. Ces locus embedded proteins control the non-ribosomal synthesis of the cereulide toxin in emetic Bacillus cereus on multiple levels

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    Genia eLücking

    2015-10-01

    Full Text Available The emetic toxin cereulide produced by Bacillus cereus is synthesized by the modular enzyme complex Ces that is encoded on a pXO1-like mega-plasmid. To decipher the role of the genes adjacent to the structural genes cesA/cesB, coding for the nonribosomal peptide synthetase (NRPS, gene inactivation- and overexpression mutants of the emetic strain F4810/72 were constructed and their impact on cereulide biosynthesis was assessed. The hydrolase CesH turned out to be a part of the complex regulatory network controlling cereulide synthesis on a transcriptional Level, while the ABC transporter CesCD was found to be essential for post-translational control of cereulide synthesis. Using a gene inactivation approach, we show that the NRPS activating function of the phosphopantetheinyl transferase (PPtase embedded in the ces locus was complemented by a chromosomally encoded Sfp-like PPtase, representing an interesting example for the functional interaction between a plasmid encoded NRPS and a chromosomally encoded activation enzyme. In summary, our results highlight the complexity of cereulide biosynthesis and reveal multiple levels of toxin formation control. ces operon internal genes were shown to play a pivotal role by acting at different levels of toxin production, thus complementing the action of the chromosomal key transcriptional regulators AbrB and CodY.

  18. A hybrid non-ribosomal peptide/polyketide synthetase containing fatty-acyl ligase (FAAL synthesizes the β-amino fatty acid lipopeptides puwainaphycins in the Cyanobacterium Cylindrospermum alatosporum.

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    Jan Mareš

    Full Text Available A putative operon encoding the biosynthetic pathway for the cytotoxic cyanobacterial lipopeptides puwainphycins was identified in Cylindrospermum alatosporum. Bioinformatics analysis enabled sequential prediction of puwainaphycin biosynthesis; this process is initiated by the activation of a fatty acid residue via fatty acyl-AMP ligase and continued by a multidomain non-ribosomal peptide synthetase/polyketide synthetase. High-resolution mass spectrometry and nuclear magnetic resonance spectroscopy measurements proved the production of puwainaphycin F/G congeners differing in FA chain length formed by either 3-amino-2-hydroxy-4-methyl dodecanoic acid (4-methyl-Ahdoa or 3-amino-2-hydroxy-4-methyl tetradecanoic acid (4-methyl-Ahtea. Because only one puwainaphycin operon was recovered in the genome, we suggest that the fatty acyl-AMP ligase and one of the amino acid adenylation domains (Asn/Gln show extended substrate specificity. Our results provide the first insight into the biosynthesis of frequently occurring β-amino fatty acid lipopeptides in cyanobacteria, which may facilitate analytical assessment and development of monitoring tools for cytotoxic cyanobacterial lipopeptides.

  19. Chemical Synthesis of Antimicrobial Peptides.

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    Münzker, Lena; Oddo, Alberto; Hansen, Paul R

    2017-01-01

    Solid-phase peptide synthesis (SPPS) is the method of choice for chemical synthesis of peptides. In this nonspecialist review, we describe commonly used resins, linkers, protecting groups, and coupling reagents in 9-fluorenylmethyloxycarbonyl (Fmoc) SPPS. Finally, a detailed protocol for manual Fmoc SPPS is presented.

  20. Solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Jensen, Knud Jørgen

    2013-01-01

    This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective....

  1. Matrix-assisted peptide synthesis on nanoparticles.

    Science.gov (United States)

    Khandadash, Raz; Machtey, Victoria; Weiss, Aryeh; Byk, Gerardo

    2014-09-01

    We report a new method for multistep peptide synthesis on polymeric nanoparticles of differing sizes. Polymeric nanoparticles were functionalized via their temporary embedment into a magnetic inorganic matrix that allows multistep peptide synthesis. The matrix is removed at the end of the process for obtaining nanoparticles functionalized with peptides. The matrix-assisted synthesis on nanoparticles was proved by generating various biologically relevant peptides. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  2. Homocysteine Editing, Thioester Chemistry, Coenzyme A, and the Origin of Coded Peptide Synthesis

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    Hieronim Jakubowski

    2017-02-01

    Full Text Available Aminoacyl-tRNA synthetases (AARSs have evolved “quality control” mechanisms which prevent tRNA aminoacylation with non-protein amino acids, such as homocysteine, homoserine, and ornithine, and thus their access to the Genetic Code. Of the ten AARSs that possess editing function, five edit homocysteine: Class I MetRS, ValRS, IleRS, LeuRS, and Class II LysRS. Studies of their editing function reveal that catalytic modules of these AARSs have a thiol-binding site that confers the ability to catalyze the aminoacylation of coenzyme A, pantetheine, and other thiols. Other AARSs also catalyze aminoacyl-thioester synthesis. Amino acid selectivity of AARSs in the aminoacyl thioesters formation reaction is relaxed, characteristic of primitive amino acid activation systems that may have originated in the Thioester World. With homocysteine and cysteine as thiol substrates, AARSs support peptide bond synthesis. Evolutionary origin of these activities is revealed by genomic comparisons, which show that AARSs are structurally related to proteins involved in coenzyme A/sulfur metabolism and non-coded peptide bond synthesis. These findings suggest that the extant AARSs descended from ancestral forms that were involved in non-coded Thioester-dependent peptide synthesis, functionally similar to the present-day non-ribosomal peptide synthetases.

  3. Automated solid-phase peptide synthesis to obtain therapeutic peptides

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    Veronika Mäde

    2014-05-01

    Full Text Available The great versatility and the inherent high affinities of peptides for their respective targets have led to tremendous progress for therapeutic applications in the last years. In order to increase the drugability of these frequently unstable and rapidly cleared molecules, chemical modifications are of great interest. Automated solid-phase peptide synthesis (SPPS offers a suitable technology to produce chemically engineered peptides. This review concentrates on the application of SPPS by Fmoc/t-Bu protecting-group strategy, which is most commonly used. Critical issues and suggestions for the synthesis are covered. The development of automated methods from conventional to essentially improved microwave-assisted instruments is discussed. In order to improve pharmacokinetic properties of peptides, lipidation and PEGylation are described as covalent conjugation methods, which can be applied by a combination of automated and manual synthesis approaches. The synthesis and application of SPPS is described for neuropeptide Y receptor analogs as an example for bioactive hormones. The applied strategies represent innovative and potent methods for the development of novel peptide drug candidates that can be manufactured with optimized automated synthesis technologies.

  4. Rapid access to glycopeptide antibiotic precursor peptides coupled with cytochrome P450-mediated catalysis: towards a biomimetic synthesis of glycopeptide antibiotics.

    Science.gov (United States)

    Brieke, Clara; Kratzig, Veronika; Haslinger, Kristina; Winkler, Andreas; Cryle, Max J

    2015-02-21

    Understanding the mechanisms underpinning glycopeptide antibiotic biosynthesis is key to the future ability to reinvent these compounds. For effective in vitro characterization of the crucial later steps of the biosynthesis, facile access to a wide range of substrate peptides as their Coenzyme A (CoA) conjugates is essential. Here we report the development of a rapid route to glycopeptide precursor CoA conjugates that affords both high yields and excellent purities. This synthesis route is applicable to the synthesis of peptide CoA-conjugates containing racemization-prone arylglycine residues: such residues are hallmarks of non-ribosomal peptide synthesis and have previously been inaccessible to peptide synthesis using Fmoc-type chemistry. We have applied this route to generate glycopeptide precursor peptides in their carrier protein-bound form as substrates to explore the specificity of the first oxygenase enzyme from vancomycin biosynthesis (OxyBvan). Our results indicate that OxyBvan is a highly promiscuous catalyst for phenolic coupling of diverse glycopeptide precursors that accepts multiple carrier protein substrates, even on carrier protein domains from alternate glycopeptide biosynthetic machineries. These results represent the first important steps in the development of an in vitro biomimetic synthesis of modified glycopeptide aglycones.

  5. Peptide synthesis in early earth hydrothermal systems

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    Lemke, K.H.; Rosenbauer, R.J.; Bird, D.K.

    2009-01-01

    We report here results from experiments and thermodynamic calculations that demonstrate a rapid, temperature-enhanced synthesis of oligopeptides from the condensation of aqueous glycine. Experiments were conducted in custom-made hydrothermal reactors, and organic compounds were characterized with ultraviolet-visible procedures. A comparison of peptide yields at 260??C with those obtained at more moderate temperatures (160??C) gives evidence of a significant (13 kJ ?? mol-1) exergonic shift. In contrast to previous hydrothermal studies, we demonstrate that peptide synthesis is favored in hydrothermal fluids and that rates of peptide hydrolysis are controlled by the stability of the parent amino acid, with a critical dependence on reactor surface composition. From our study, we predict that rapid recycling of product peptides from cool into near-supercritical fluids in mid-ocean ridge hydrothermal systems will enhance peptide chain elongation. It is anticipated that the abundant hydrothermal systems on early Earth could have provided a substantial source of biomolecules required for the origin of life. Astrobiology 9, 141-146. ?? 2009 Mary Ann Liebert, Inc. 2009.

  6. Parallel synthesis and screening of peptide conjugates.

    Science.gov (United States)

    Dirksen, Anouk; Madsen, Mark; Dello Iacono, Giuseppe; Matin, Marla J; Bacica, Michael; Stanković, Nebojša; Callans, Sherri; Bhat, Abhijit

    2014-06-18

    Peptide conjugates represent an emerging class of therapeutics. However, in contrast to that of small molecules and peptides, the discovery and optimization of peptide conjugates is low in throughput, resource intensive, time-consuming, and based on educated decisions rather than screening. A strategy for the parallel synthesis and screening of peptide conjugates is presented that (1) reduces variability in the conjugation steps; (2) provides a new method to rapidly and quantitatively measure conversion in crude conjugation mixtures; (3) introduces a purification step using an immobilized chemical scavenger that does not rely on protein-specific binding; and (4) is supported by robust analytical methods to characterize the large number of end products. Copper-free click chemistry is used as the chemoselective ligation method for conjugation and purification. The productivity in the generation and screening of peptide conjugates is significantly improved by applying this strategy as is demonstrated by the optimization of the anti-Angiopoietin-2 (Ang2) CovX-body, CVX-060, a peptide-antibody scaffold conjugate that has advanced in clinical trials for oncology indications.

  7. Obviation of hydrogen fluoride in Boc chemistry solid phase peptide synthesis of peptide-αthioesters.

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    Gates, Zachary P; Dhayalan, Balamurugan; Kent, Stephen B H

    2016-11-29

    Under suitable conditions, trifluoromethanesulfonic acid performs comparably to hydrogen fluoride for the on-resin global deprotection of peptides prepared by Boc chemistry solid phase peptide synthesis (SPPS). Obviation of hydrogen fluoride in Boc chemistry SPPS enables the straightforward synthesis of peptide- α thioesters for use in native chemical ligation.

  8. Chemo-enzymatic peptide synthesis : bioprocess engineering aspects

    NARCIS (Netherlands)

    Vossenberg, P.

    2012-01-01

    Peptides, in particular oligopeptides, play an important role in the fields of health care, nutrition and cosmetics. Chemical synthesis is currently the most mature technique for the synthesis of peptides that range in length from 5 to 80 amino acids. Chemical synthesis is, however,

  9. SOLID-PHASE PEPTIDE SYNTHESIS OF ISOTOCIN WITH AMIDE ...

    African Journals Online (AJOL)

    SOLID-PHASE PEPTIDE SYNTHESIS OF ISOTOCIN WITH AMIDE OF ASPARAGINE PROTECTED WITH 1-TETRALINYL. TRIFLUOROMETHANESULPHONIC ACID (TFMSA) DEPROTECTION, CLEAVAGE AND AIR OXIDATION OF MERCAPTO GROUPS TO DISULPHIDE.

  10. Versatile synthesis of the signaling peptide glorin

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    Robert Barnett

    2017-02-01

    Full Text Available We present a versatile synthesis of the eukaryotic signaling peptide glorin as well as glorinamide, a synthetic analog. The ability of these compounds to activate glorin-induced genes in the social amoeba Polysphondylium pallidum was evaluated by quantitative reverse transcription PCR, whereby both compounds showed bioactivity comparable to a glorin standard. This synthetic route will be useful in conducting detailed structure–activity relationship studies as well as in the design of chemical probes to dissect glorin-mediated signaling pathways.

  11. Peptide synthesis in neat organic solvents with novel thermostable proteases

    NARCIS (Netherlands)

    Toplak, Ana; Nuijens, Timo; Quaedflieg, Peter J L M; Wu, Bian; Janssen, Dick B

    Biocatalytic peptide synthesis will benefit from enzymes that are active at low water levels in organic solvent compositions that allow good substrate and product solubility. To explore the use of proteases from thermophiles for peptide synthesis under such conditions, putative protease genes of the

  12. Selective 'in synthesis' labeling of peptides with biotin and rhodamine.

    Science.gov (United States)

    Chersi, A; Giommi, S; Rosanò, L

    2000-04-06

    A new method is described for the selective 'in synthesis' labeling of peptides by rhodamine or biotin at a single, predetermined epsilon-amino group of a lysine residue. The alpha-amino group and other lysyl residues of the peptide remain unmodified. Peptides are assembled by the Fmoc approach, which requires mild operative conditions for the final deprotection and cleavage, and ensures little damage of the reporter group. The labeling technique involves the previous preparation of a suitable Lysine derivative, easily obtained from commercially-available protected amino acids. This new derivative, where the reporter group (biotin, or rhodamine) acts now as permanent protection of lysyl side chain functions, is then inserted into the synthesis program as a conventional protected amino acid, and linked to the preceding residue by aid of carbodiimide. A simpler, alternative method is also described for the selective 'in synthesis' labeling of peptides with N-terminal lysyl residues. Several applications of labeled peptides are reported.

  13. Synthesis of peptide-grafted comb polypeptides via polymerisation of NCA-peptides.

    Science.gov (United States)

    Enomoto, Hiroshi; Nottelet, Benjamin; Halifa, Soultan Al; Enjalbal, Christine; Dupré, Mathieu; Tailhades, Julien; Coudane, Jean; Subra, Gilles; Martinez, Jean; Amblard, Muriel

    2013-01-14

    A straightforward synthesis of comb-polypeptides of repeated peptide sequences was developed. These polypeptides were obtained by ROP of defined NCA without any post-polymerization grafting. The key to this strategy relies on the preparation of pure NCA bearing a peptide sequence on its side chain, by an original solid supported methodology.

  14. Ribosome evolution: Emergence of peptide synthesis machinery

    Indian Academy of Sciences (India)

    allows the histidine to position close to the PTC during the reaction, it may contribute to improving peptide bond formation. Thus, it is important to analyse biomolecular interactions in terms of the dynamic nature of the structure. 3. Origin of peptide bond formation and the RNA world. Minihelix-based peptide bond formation ...

  15. Microwave heating in solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Pedersen, Søren Ljungberg; Shelton, Anne Pernille Tofteng; Malik, Leila

    2012-01-01

    synthesis, precise microwave irradiation to heat the reaction mixture during coupling and N(a)-deprotection has become increasingly popular. It has often provided dramatic reductions in synthesis times, accompanied by an increase in the crude peptide purity. Microwave heating has been proven especially...... relevant for sequences which might form ß-sheet type structures and for sterically difficult couplings. The beneficial effect of microwave heating appears so far to be due to the precise nature of this type of heating, rather than a peptide-specific microwave effect. However, microwave heating...... in microwave heating for peptide synthesis, with a focus on systematic studies and general protocols, as well as important applications. The assembly of ß-peptides, peptoids and pseudopeptides are also evaluated in this critical review (254 references)....

  16. Chemoselective synthesis of functional homocysteine residues in polypeptides and peptides.

    Science.gov (United States)

    Gharakhanian, Eric G; Deming, Timothy J

    2016-04-18

    A methodology was developed for efficient, chemoselective transformation of methionine residues into stable, functional homocysteine derivatives. Methionine residues can undergo highly chemoselective alkylation reactions at low pH to yield stable sulfonium ions, which could then be selectively demethylated to give stable alkyl homocysteine residues. This mild, two-step process is chemoselective, efficient, tolerates many functional groups, and provides a means for creation of new functional biopolymers, site-specific peptide tagging, and synthesis of biomimetic and structural analogs of peptides.

  17. Selective 'in synthesis' labelling of peptides by fluorochromes.

    Science.gov (United States)

    Chersi, A; di Modugno, F; Rosanò, L

    1997-07-19

    A new method is described for producing fluorescently-tagged peptides containing specific internal derivatives of lysyl residues. The technique employs the base-labile Boc-Lys(Fmoc)-COOH derivative with base-catalyzed removal of the Fmoc protecting group during peptide synthesis and subsequent fluorescent derivatization of the deprotected epsilon-amino group of lysine. By this technique, other lysine residues and the alpha-amino group of the fragment remain unmodified, which could have some value in studies where it might be required to tag a single individual lysine residue within the peptide, but not the amino terminus. In spite of the fact that poly-substituted peptides are badly soluble and might seldom find a practical application, this technique also allows the introduction of different fluorochromes at different lysyl residues within the peptide, thus obtaining double fluorescence. The method, fast and easy, requires a limited number of manual operations during the automatic synthesis of peptides. Although peptide synthesizers provided with an oscillating glass reactor are more suitable for the manual interventions described, this technique might be also adapted to the newer instruments utilizing continuous-flow columns.

  18. Triazole-linked glycosyl amino acids and peptides : synthesis

    NARCIS (Netherlands)

    Kuijpers, B.H.M.

    2008-01-01

    Naturally occurring glycosylated peptides play an important role in various biological processes and are therefore interesting lead molecules for the preparation of new therapeutic drugs.Synthesis of these natural glycopeptides is frequently hampered by the sensitivity of the natural glycosidic

  19. Peptide protected gold clusters: chemical synthesis and biomedical applications.

    Science.gov (United States)

    Yuan, Qing; Wang, Yaling; Zhao, Lina; Liu, Ru; Gao, Fuping; Gao, Liang; Gao, Xueyun

    2016-06-16

    Bridging the gap between atoms and nanoparticles, noble metal clusters with atomic precision continue to attract considerable attention due to their important applications in catalysis, energy transformation, biosensing and biomedicine. Greatly different to common chemical synthesis, a one-step biomimetic synthesis of peptide-conjugated metal clusters has been developed to meet the demand of emerging bioapplications. Under mild conditions, multifunctional peptides containing metal capturing, reactive and targeting groups are rationally designed and elaborately synthesized to fabricate atomically precise peptide protected metal clusters. Among them, peptide-protected Au Cs (peptide-Au Cs) possess a great deal of exceptional advantages such as nanometer dimensions, high photostability, good biocompatibility, accurate chemical formula and specific protein targeting capacity. In this review article, we focus on the recent advances in potential theranostic fields by introducing the rising progress of peptide-Au Cs for biological imaging, biological analysis and therapeutic applications. The interactions between Au Cs and biological systems as well as potential mechanisms are also our concerned theme. We expect that the rapidly growing interest in Au Cs-based theranostic applications will attract broader concerns across various disciplines.

  20. Ribosome evolution: Emergence of peptide synthesis machinery

    Indian Academy of Sciences (India)

    In this article, a possible evolutionary pathway to peptide bond formation machinery (proto-ribosome) will be discussed, with a special focus on the RNA minihelix (primordial form of modern tRNA) as a starting molecule. Combining the present data with recent experimental data, we can infer that the peptidyl transferase ...

  1. Thionin antifungal peptide synthesis in transgenic barley

    Science.gov (United States)

    In seeds and vegetative organs of barley and other cereals, thionins are processed into peptides with pronounced anti-microbial properties. In vitro studies demonstrated the toxicity of a- and ß-hordothionins (HTHs) to the fungal pathogen Fusarium graminearum. Increasing the expression of thionin g...

  2. FUNCTIONALIZED CALIXSPHERANDS - SYNTHESIS AND PEPTIDE COUPLING

    NARCIS (Netherlands)

    BAKKER, WII; HAAS, M; DENHERTOG, HJ; VERBOOM, W; DEZEEUW, D; BRUINS, AP; REINHOUDT, DN

    1994-01-01

    Calixspherands, like 1, form kinetically stable complexes with alkali metal cations. For practical in vivo applications coupling of these complexes with carrier molecules is mandatory, Therefore, a general method for the synthesis of functionalized calixspherand 17 was developed starting from

  3. Peptide Synthesis on a Next-Generation DNA Sequencing Platform.

    Science.gov (United States)

    Svensen, Nina; Peersen, Olve B; Jaffrey, Samie R

    2016-09-02

    Methods for displaying large numbers of peptides on solid surfaces are essential for high-throughput characterization of peptide function and binding properties. Here we describe a method for converting the >10(7) flow cell-bound clusters of identical DNA strands generated by the Illumina DNA sequencing technology into clusters of complementary RNA, and subsequently peptide clusters. We modified the flow-cell-bound primers with ribonucleotides thus enabling them to be used by poliovirus polymerase 3D(pol) . The primers hybridize to the clustered DNA thus leading to RNA clusters. The RNAs fold into functional protein- or small molecule-binding aptamers. We used the mRNA-display approach to synthesize flow-cell-tethered peptides from these RNA clusters. The peptides showed selective binding to cognate antibodies. The methods described here provide an approach for using DNA clusters to template peptide synthesis on an Illumina flow cell, thus providing new opportunities for massively parallel peptide-based assays. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Stereocontrolled Synthesis of Methyl Silanediol Peptide Mimics

    DEFF Research Database (Denmark)

    Nielsen, Lone; Lindsay, Karl; Faber, Jesper

    2007-01-01

     The treatment of chiral sulfinimines with (methyldiphenylsilyl)lithium gives R-(methyldiphenylsilyl)-sulfinamides with excellent diastereoselectivity, and in good yield. The presence of α-protons on the imines is also well tolerated. The sulfinamide auxiliary is easily removed via treatment with...... corresponding bis-TMS siloxane via protection with TMSCl, and converted back to the desired silanediol via hydrolysis with aqueous KOH. Efforts to apply this approach to biologically relevant silanediol peptide mimics, with a view to protease inhibition, are described....

  5. Synthesis of peptides using tert-butyloxycarbonyl (Boc) as the α-amino protection group

    DEFF Research Database (Denmark)

    Pedersen, Søren W; Armishaw, Christopher J; Strømgaard, Kristian

    2013-01-01

    The use of the tert-butyloxycarbonyl (Boc) as the Nα-amino protecting group in peptide synthesis can be advantageous in several cases, such as synthesis of hydrophobic peptides and peptides containing ester and thioester moieties. The primary challenge of using Boc SPPS is the need for treatment...

  6. Purification and use of E. coli peptide deformylase for peptide deprotection in chemoenzymatic peptide synthesis

    NARCIS (Netherlands)

    Di Toma, Claudia; Sonke, Theo; Quaedflieg, Peter J.; Janssen, Dick B.

    Peptide deformylases (PDFs) catalyze the removal of the formyl group from the N-terminal methionine residue in nascent polypeptide chains in prokaryotes. Its deformylation activity makes PDF an attractive candidate for the biocatalytic deprotection of formylated peptides that are used in

  7. Semi-automated microwave assisted solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Pedersen, Søren Ljungberg

    with microwaves for SPPS has gained in popularity as it for many syntheses has provided significant improvement in terms of speed, purity, and yields, maybe especially in the synthesis of long and "difficult" peptides. Thus, precise microwave heating has emerged as one new parameter for SPPS, in addition...... to coupling reagents, resins, solvents etc. We have previously reported on microwave heating to promote a range of solid-phase reactions in SPPS. Here we present a new, flexible semi-automated instrument for the application of precise microwave heating in solid-phase synthesis. It combines a slightly modified...... Biotage Initiator microwave instrument, which is available in many laboratories, with a modified semi-automated peptide synthesizer from MultiSynTech. A custom-made reaction vessel is placed permanently in the microwave oven, thus the reactor does not have to be moved between steps. Mixing is achieved...

  8. Chemical Synthesis of Human Insulin-Like Peptide-6.

    Science.gov (United States)

    Wu, Fangzhou; Mayer, John P; Zaykov, Alexander N; Zhang, Fa; Liu, Fa; DiMarchi, Richard D

    2016-07-04

    Human insulin-like peptide-6 (INSL-6) belongs to the insulin superfamily and shares the distinctive disulfide bond configuration of human insulin. In this report we present the first chemical synthesis of INSL-6 utilizing fluorenylmethyloxycarbonyl-based (Fmoc) solid-phase peptide chemistry and regioselective disulfide bond construction protocols. Due to the presence of an oxidation-sensitive tryptophan residue, two new orthogonal synthetic methodologies were developed. The first method involved the identification of an additive to suppress the oxidation of tryptophan during iodine-mediated S-acetamidomethyl (Acm) deprotection and the second utilized iodine-free, sulfoxide-directed disulfide bond formation. The methodologies presented here offer an efficient synthetic route to INSL-6 and will further improve synthetic access to other multiple-disulfide-containing peptides with oxidation-sensitive residues. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Lanthanide-Mediated Dephosphorylation Used for Peptide Cleavage during Solid Phase Peptide Synthesis

    Directory of Open Access Journals (Sweden)

    Byunghee Yoo

    2013-04-01

    Full Text Available Lanthanide(III ions can accelerate the hydrolysis of phosphomonoesters and phosphodiesters in neutral aqueous solution. In this paper, lanthanide-mediated dephosphorylation has been applied in aqueous media as an orthogonal cleavage condition that can be employed in conventional solid phase peptide synthesis (SPPS. A phosphorylated polymeric support for SPPS was developed using Boc chemistry. The cleavage of resin-bound phosphates was investigated with the addition of Eu(III, Yb(III, acid or base, a mixture of solvents or different temperatures. To demonstrate the utility of this approach for SPPS, a peptide sequence was synthesized on a phosphorylated polymeric support and quantitatively cleaved with lanthanide ions in neutral aqueous media. The protecting groups for side chains were retained during peptide cleavage using lanthanide ions. This new methodology provides a mild orthogonal cleavage condition of phosphoester as a linker during SPPS.

  10. Linkers, resins, and general procedures for solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Shelton, Anne Pernille Tofteng; Jensen, Knud Jørgen

    2013-01-01

    and linkers for solid-phase synthesis is a key parameter for successful peptide synthesis. This chapter provides an overview of the most common and useful resins and linkers for the synthesis of peptides with C-terminal amides, carboxylic acids, and more. The chapter finishes with robust protocols for general...

  11. Studies in Solid Phase Peptide Synthesis: A Personal Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, A R

    2007-06-01

    By the early 1970s it had became apparent that the solid phase synthesis of ribonuclease A could not be generalized. Consequently, virtually every aspect of solid phase peptide synthesis (SPPS) was reexamined and improved during the decade of the 1970s. The sensitive detection and elimination of possible side reactions (amino acid insertion, N{sup {alpha}}-trifluoroacetylation, N{sup {alpha}{var_epsilon}}-alkylation) was examined. The quantitation of coupling efficiency in SPPS as a function of chain length was studied. A new and improved support for SPPS, the 'PAM-resin', was prepared and evaluated. These and many other studies from the Merrifield laboratory and elsewhere increased the general acceptance of SPPS leading to the 1984 Nobel Prize in Chemistry for Bruce Merrifield.

  12. Semi-automated microwave assisted solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Pedersen, Søren Ljungberg

    measurements during microwave heating. Then we developed protocols for on-resin reductive amination for anchoring of the first amino acids to a BAL handle. Finally, we used the new instrument and the optimized protocols to assist in the synthesis of a range of difficult and long sequences. We believe...... to coupling reagents, resins, solvents etc. We have previously reported on microwave heating to promote a range of solid-phase reactions in SPPS. Here we present a new, flexible semi-automated instrument for the application of precise microwave heating in solid-phase synthesis. It combines a slightly modified...... Biotage Initiator microwave instrument, which is available in many laboratories, with a modified semi-automated peptide synthesizer from MultiSynTech. A custom-made reaction vessel is placed permanently in the microwave oven, thus the reactor does not have to be moved between steps. Mixing is achieved...

  13. Carbohydrate protease conjugates: Stabilized proteases for peptide synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Wartchow, C.A.; Wang, Peng; Bednarski, M.D.; Callstrom, M.R. [Ohio State Univ., Columbus, OH (United States)]|[Lawrence Berkeley Lab., CA (United States)

    1995-12-31

    The synthesis of oligopeptides using stable carbohydrate protease conjugates (CPCs) was examined in acetonitrile solvent systems. CPC[{alpha}-chymotrypsin] was used for the preparation of peptides containing histidine, phenylalanine, tryptophan in the P{sub 1} position in 60-93% yield. The CPC[{alpha}-chymotrypsin]-catalyzed synthesis of octamer Z-Gly-Gly-Phe-Gly-Gly-Phe-Gly-Gly-OEt from Z-Gly-Gly-Phe-Gly-Gly-Phe-OMe was achieved in 71% yield demonstrating that synthesis peptides containing both hydrophylic and hydrophobic amino acids. The P{sub 2} specificity of papain for aromatic residues was utilized for the 2 + 3 coupling of Z-Tyr-Gly-OMe to H{sub 2}N-Gly-Phe-Leu-OH to generate the leucine enkephalin derivative in 79% yield. Although papain is nonspecific for the hydrolysis of N-benzyloxycarbonyl amino acid methyl esters in aqueous solution, the rates of synthesis for these derivitives with nucleophile leucine tert-butyl ester differed by nearly 2 orders of magnitude. CPC[thermolysin] was used to prepare the aspartame precursor Z-Asp-Phe-OMe in 90% yield. The increased stability of CPCs prepared from periodate-modified poly(2-methacryl- amido-2-deoxy-D-glucose), poly(2-methacrylamido-2-deoxy-D-galactose), and poly(5-methacryl-amido-5-deoxy-D-ribose), carbohydrate materials designed to increase the aldehyde concentration in aqueous solution, suggests that the stability of CPCs is directly related to the aldehyde concentration of the carbohydrate material. Periodate oxidation of poly(2-methacrylamido-2-deoxy-D-glucose) followed by covalent attachment to {alpha}-chymotrypsin gave a CPC with catalytic activity in potassium phosphate buffer at 90{degrees}C for 2 h. 1 fig., 1 tab., 40 refs.

  14. Implementation of communication-mediating domains for non-ribosomal peptide production in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Siewers, Verena; San-Bento, Rita; Nielsen, Jens

    2010-01-01

    are often organized in enzyme complexes. In these complexes, partner NRPSs interact via communication-mediating domains (COM domains). In order to test whether functional interaction between separate NRPS modules is possible in yeast we constructed a yeast strain expressing two modules with compatible COM...

  15. R. Bruce Merrifield and Solid-Phase Peptide Synthesis: A Historical Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, A R

    2007-12-04

    Bruce Merrifield, trained as a biochemist, had to address three major challenges related to the development and acceptance of solid-phase peptide synthesis (SPPS). The challenges were (1) to reduce the concept of peptide synthesis on a insoluble support to practice, (2) overcome the resistance of synthetic chemists to this novel approach, and (3) establish that a biochemist had the scientific credentials to effect the proposed revolutionary change in chemical synthesis. How these challenges were met is discussed in this article.

  16. Effect of Microwave Radiation on Enzymatic and Chemical Peptide Bond Synthesis on Solid Phase

    Directory of Open Access Journals (Sweden)

    Alessandra Basso

    2009-01-01

    Full Text Available Peptide bond synthesis was performed on PEGA beads under microwave radiations. Classical chemical coupling as well as thermolysin catalyzed synthesis was studied, and the effect of microwave radiations on reaction kinetics, beads' integrity, and enzyme activity was assessed. Results demonstrate that microwave radiations can be profitably exploited to improve reaction kinetics in solid phase peptide synthesis when both chemical and biocatalytic strategies are used.

  17. HF-Free Boc Synthesis of Peptide Thioesters for Ligation and Cyclization.

    Science.gov (United States)

    Raz, Richard; Burlina, Fabienne; Ismail, Mohamed; Downward, Julian; Li, Jiejin; Smerdon, Stephen J; Quibell, Martin; White, Peter D; Offer, John

    2016-10-10

    We have developed a convenient method for the direct synthesis of peptide thioesters, versatile intermediates for peptide ligation and cyclic peptide synthesis. The technology uses a modified Boc SPPS strategy that avoids the use of anhydrous HF. Boc in situ neutralization protocols are used in combination with Merrifield hydroxymethyl resin and TFA/TMSBr cleavage. Avoiding HF extends the scope of Boc SPPS to post-translational modifications that are compatible with the milder cleavage conditions, demonstrated here with the synthesis of the phosphorylated protein CHK2. Peptide thioesters give easy, direct, access to cyclic peptides, illustrated by the synthesis of cyclorasin, a KRAS inhibitor. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  18. Synthesis of Orthogonally Protected Muramic Acid Building Blocks for Solid Phase Peptide Synthesis

    Directory of Open Access Journals (Sweden)

    Kristina Vlahoviček-Kahlina

    2015-07-01

    Full Text Available Muramic acid is found in many peptide natural products containing oligo(polysaccharide moieties. Taking into consideration that the Fmoc methodology is routinely used for solid-phase peptide synthesis, preparation of orthogonally protected muramic acid building blocks for total solid-phase synthesis of these natural products is of particular practical importance. Herein a simple and efficient synthesis of benzyl 2-amino-4,6-O-benzylidene-3-O-[(R-1-carboxyethyl]-2-deoxy-N-9-fluorenylmethyloxycarbonyl-α-D-glucopyranoside (6 from N-acetylglucosamine (1 is described. Important improvements over previous synthetic approaches to glucopyranosides 2 (benzyl 2-acetamido-2-deoxy-α-D-glucopyranoside and 3 (benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-α-D-glucopyranoside, key building blocks in preparation of 6, include synthesis simplification and efficient isolation and purification. Optically pure (S-2-chloropropionic acid 7 was prepared and introduced to the positon 3-O of sugar moiety to give compound 4 (benzyl 2-acetamido-4,6-O-benzylidene-3-O-[(R-1-carboxyethyl]-2-deoxy-α-D-glucopyranoside with the (R-configuration of the lactyl side-chain in excellent overall yield and optical purity. Deacetylation of amino group gave compound 5 (benzyl 2-amino-4,6-O-benzylidene-3-O-[(R-1-carboxyethyl]-2-deoxy-α-D-glucopyranoside suitable for incorporation of the Fmoc protecting group to give protected muramic acid derivative 6, a useful building block in peptide synthesis.

  19. Soy peptide ingestion augments the synthesis and metabolism of noradrenaline in the mouse brain.

    Science.gov (United States)

    Imai, Haruka; Moriyasu, Kazuki; Nakahata, Akane; Maebuchi, Motohiro; Ichinose, Takashi; Furuya, Shigeki

    2017-05-01

    To examine whether edible peptide intake affects neurotransmitter metabolism in the brain, we evaluated the effect of peptides derived from soy proteins or fish collagen on free amino acids and monoamines in the mouse brain. Ingestion of soy peptides led to markedly higher levels of tyrosine, a catecholamine precursor, in the serum, and cerebral cortex compared to those following ingestion of vehicle alone or collagen peptides. Soy peptide ingestion also effectively increased 3-methoxy-4-hydroxyphenylethyleneglycol and normetanephrine, the principal metabolites of noradrenaline, in the cerebral cortex, hippocampus, and brainstem, whereas collagen peptides did not exert such effects. Further, soy peptide ingestion led to a significant increase in noradrenaline itself in the brainstem, where noradrenergic neurons are present. Noradrenergic turnover was also markedly stimulated in these regions after soy peptide ingestion. These in vivo observations suggest that soy peptide ingestion can maintain and promote the synthesis and metabolism of noradrenaline in the brain.

  20. Chemo-enzymatic peptide synthesis and derivatisation using Subtilisin A in anhydrous organic solvents

    OpenAIRE

    Nuijens, T.

    2012-01-01

    In this thesis it is demonstrated that Alcalase and Cal-B in neat organic solvent can perform unique and cost-efficient conversions that are useful in the peptide area. Not only can Alcalase be used to prepare several C-terminally derivatized amino acids and peptides (such as amides, esters and arylamides), this protease is also a very efficient catalyst for peptide bond formation (optionally combined with Cal-B for ester synthesis) or even for fully enzymatic peptide synthesis strategies bas...

  1. Peptide synthesis: ball-milling, in solution, or on solid support, what is the best strategy?

    Directory of Open Access Journals (Sweden)

    Ophélie Maurin

    2017-10-01

    Full Text Available While presenting particularly interesting advantages, peptide synthesis by ball-milling was never compared to the two traditional strategies, namely peptide syntheses in solution and on solid support (solid-phase peptide synthesis, SPPS. In this study, the challenging VVIA tetrapeptide was synthesized by ball-milling, in solution, and on solid support. The three strategies were then compared in terms of yield, purity, reaction time and environmental impact. The results obtained enabled to draw some strengths and weaknesses of each strategy, and to foresee what will have to be implemented to build more efficient and sustainable peptide syntheses in the near future.

  2. Use of the 2-chlorotrityl chloride resin for microwave-assisted solid phase peptide synthesis.

    Science.gov (United States)

    Ieronymaki, Matthaia; Androutsou, Maria Eleni; Pantelia, Anna; Friligou, Irene; Crisp, Molly; High, Kirsty; Penkman, Kirsty; Gatos, Dimitrios; Tselios, Theodore

    2015-09-01

    A fast and efficient microwave (MW)-assisted solid-phase peptide synthesis protocol using the 2-chlorotrityl chloride resin and the Fmoc/tBu methodology, has been developed. The established protocol combines the advantages of MW irradiation and the acid labile 2-chlorotrityl chloride resin. The effect of temperature during the MW irradiation, the degree of resin substitution during the coupling of the first amino acids and the rate of racemization for each amino acid were evaluated. The suggested solid phase methodology is applicable for orthogonal peptide synthesis and for the synthesis of cyclic peptides. © 2015 Wiley Periodicals, Inc.

  3. Use of FTIR in the obtention of resins and peptides synthesis in solid phase

    International Nuclear Information System (INIS)

    Cespedes, Graziely Ferreira; Vicente, Eduardo Festozo; Cilli, Eduardo Maffud; Jubilut, Guita Nicolaewsky; Nakaie, Clovis Ryuichi

    2011-01-01

    Despite the increase in peptide chain aggregation, which decreases the rate of coupling reactions, the synthesis and use of very highly substituted resins still remains as a controversial point in the SPPS, due to its clear economical advantages (lesser solvent consumption and higher amount of peptide per synthesis). In order to better investigate the synthesis and the use of very highly substituted resins, the FTIR, NMR and EPR were compared. By FTIR techniques it was possible to follow all the steps of resin synthesis and the factors affecting the aggregation of the chains inside the peptidil-BHAR and MBHAR. (author)

  4. Ribosome-mediated synthesis of natural product-like peptides via cell-free translation.

    Science.gov (United States)

    Maini, Rumit; Umemoto, Shiori; Suga, Hiroaki

    2016-10-01

    Peptide natural products (PNPs) represent a unique class of compounds known for their fascinating structural motifs with important biological activities. Lately, PNPs have garnered a lot of interest for their application in drug discovery. Nevertheless, lack of diversity oriented synthetic/biosynthetic platforms to generate large natural product-like libraries has limited their development as peptide therapeutics. The promiscuity of cell-free translation has allowed for the synthesis of artificial PNPs having complex structural features. Modified cell-free translation systems coupled with the display technologies have generated diverse natural product-like peptide libraries and led to the discovery of several biologically active molecules. Such technologies have drastically decreased the time to obtain peptide drug leads and therefore, revolutionized the field of peptide drug discovery. In this account, we review recent developments in the synthesis of natural product-like peptides via cell-free translation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Chemical synthesis of biologically active monoglycosylated GM2-activator protein analogue using N-sulfanylethylanilide peptide.

    Science.gov (United States)

    Sato, Kohei; Shigenaga, Akira; Kitakaze, Keisuke; Sakamoto, Ken; Tsuji, Daisuke; Itoh, Kohji; Otaka, Akira

    2013-07-22

    Going to SEA(lide): Total chemical synthesis of a 162-residue glycoprotein analogue of the monoglycosylated human GM2-activator protein (GM2AP) was achieved. Key steps were the use of N-sulfanylethylanilide (SEAlide) peptides in the kinetic chemical ligation synthesis of a large peptide fragment, and a convergent native chemical ligation for final fragment assembly. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Development and use of engineered peptide deformylase in chemoenzymatic peptide synthesis

    NARCIS (Netherlands)

    Di Toma, Claudia

    2012-01-01

    Deze thesis beschrijft het onderzoek naar potentieel van het gebruik van het peptide deformylase (PDF) in chemo enzymatische peptide synthese. PDF is geschikt voor selective N terminale deformylatie van bepaalde N-formyl-peptides zonder gelijktijdige hydrolyse van de peptide binding. Door de

  7. Role of leader peptide synthesis in tryptophanase operon expression in Escherichia coli K-12.

    OpenAIRE

    Stewart, V; Yanofsky, C

    1986-01-01

    We used site-directed mutagenesis to replace the Escherichia coli tryptophanase (tna) operon leader peptide start codon with AUC. This change greatly decreased the uninduced rate of tna operon expression, and it also lowered the response to inducer. We conclude that leader peptide synthesis plays an essential role in tna operon expression.

  8. Screening And Optimizing Antimicrobial Peptides By Using SPOT-Synthesis

    Science.gov (United States)

    López-Pérez, Paula M.; Grimsey, Elizabeth; Bourne, Luc; Mikut, Ralf; Hilpert, Kai

    2017-04-01

    Peptide arrays on cellulose are a powerful tool to investigate peptide interactions with a number of different molecules, for examples antibodies, receptors or enzymes. Such peptide arrays can also be used to study interactions with whole cells. In this review, we focus on the interaction of small antimicrobial peptides with bacteria. Antimicrobial peptides (AMPs) can kill multidrug-resistant (MDR) human pathogenic bacteria and therefore could be next generation antibiotics targeting MDR bacteria. We describe the screen and the result of different optimization strategies of peptides cleaved from the membrane. In addition, screening of antibacterial activity of peptides that are tethered to the surface is discussed. Surface-active peptides can be used to protect surfaces from bacterial infections, for example implants.

  9. Discovery and engineering of enzymes for chemoenzymatic peptide synthesis

    NARCIS (Netherlands)

    Toplak, Ana

    2016-01-01

    The use of peptides and proteins as therapeutic agents, nutritional additives or cosmetic ingredients is becoming more prominent. The number of therapeutic peptides in development is increasing, as well as their length, complexity and quantity requirements. An attractive approach for peptide

  10. Peptide o-aminoanilides as crypto-thioesters for protein chemical synthesis.

    Science.gov (United States)

    Wang, Jia-Xing; Fang, Ge-Min; He, Yao; Qu, Da-Liang; Yu, Min; Hong, Zhang-Yong; Liu, Lei

    2015-02-09

    Fully unprotected peptide o-aminoanilides can be efficiently activated by NaNO2 in aqueous solution to furnish peptide thioesters for use in native chemical ligation. This finding enables the convergent synthesis of proteins from readily synthesizable peptide o-aminoanilides as a new type of crypto-thioesters. The practicality of this approach is shown by the synthesis of histone H2B from five peptide segments. Purification or solubilization tags, which are sometimes needed to improve the efficiency of protein chemical synthesis, can be incorporated into the o-aminoanilide moiety, as demonstrated in the preparation of the cyclic protein lactocyclicin Q. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Novel Methods for the Chemical Synthesis of Insulin Superfamily Peptides and of Analogues Containing Disulfide Isosteres.

    Science.gov (United States)

    Hossain, Mohammed Akhter; Wade, John D

    2017-09-19

    The insulin superfamily of peptides is ubiquitous within vertebrates and invertebrates and is characterized by the presence of a set of three disulfide bonds in a unique disposition. With the exception of insulin-like growth factors I and II, which are single chain peptides, the remaining 8 members of the human insulin superfamily are two-chain peptides containing one intramolecular and two intermolecular disulfide bridges. These structural features have long made the chemical synthesis of the peptides a considerable challenge, in particular, including their correct disulfide bond pairing and formation. However, they have also afforded the opportunity to develop modern solid phase synthesis methods for the preparation of such peptides that incorporate novel or improved chemical methods for the controlled introduction of both disulfide bonds and their surrogates, both during and after peptide chain assembly. In turn, this has enabled a detailed probing of the structure and function relationship of this small but complex superfamily of peptides. After initially using and subsequently identifying significant limitations of the approach of simultaneous random chain combination and oxidative folding, our laboratory undertook to develop robust chemical synthesis strategies in concert with orthogonal cysteine S-protecting groups and corresponding regioselective disulfide bond formation. These have included the separate synthesis of each of the two chains or of the two chains linked by an artificial C-peptide that is removed following postoxidative folding. These, in turn, have enabled an increased ease of acquisition in a good yield of not only members of human insulin superfamily but other insulin-like peptides. Importantly, these successful methods have enabled, for the first time, a detailed analysis of the role that the disulfide bonds play in the structure and function of such peptides. This was achieved by selective removal of the disulfide bonds or by the judicious

  12. Design, synthesis and analysis of novel Smac-based peptides

    Czech Academy of Sciences Publication Activity Database

    Georgieva, M.; Dzimbova, T.; Sázelová, Petra; Detcheva, R.; Kašička, Václav; Pajpanova, T.

    2014-01-01

    Roč. 20, Suppl S1 (2014), S225-S226 ISSN 1075-2617. [European Peptide Symposium /33./. 31.08.2014-05.09.2014, Sofia] Institutional support: RVO:61388963 Keywords : apoptotic peptides * Smac -mimetics * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation

  13. Primordial and Modern Self Assembling Peptides: Synthesis and Characterization

    Science.gov (United States)

    Cusumano, Stephen

    The creation and analysis of self-assembling peptides has become a recent research trend due to the wide range of applications and usages. Modern self-assembling such as lanreotide, which is an established anti-cancer drug in the pharmaceutical industry, can be synthetically made. More primitive peptides, such as those discovered to be present in the famous Miller experiment, which replicated the primordial earth atmosphere, are representative of a different aspect of self-assembling peptides. If these novel peptides are found to self-assemble, this will give researchers new insight on how primitive cells first formed on this planet to give rise to life. Using the established nanotube structure of lanreotide, TEM protocols were developed to obtain similar high quality TEM images of primitive peptides, to observe if any structures have begun to form.

  14. Recent extensions to native chemical ligation for the chemical synthesis of peptides and proteins.

    Science.gov (United States)

    Malins, Lara R; Payne, Richard J

    2014-10-01

    Native chemical ligation continues to play a pivotal role in the synthesis of increasingly complex peptide and protein targets twenty years after its initial report. This opinion article will highlight a number of recent, powerful extensions of the technology that have expanded the scope of the reaction, accelerated ligation rates, enabled chemoselective post-ligation modifications, and streamlined the ligation of multiple peptide fragments. These advances have facilitated the synthesis of a number of impressive protein targets to date and hold great promise for the continued application of native chemical ligation for the detailed study of protein structure and function. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Synthesis of thioester peptides for the incorporation of thioamides into proteins by native chemical ligation.

    Science.gov (United States)

    Batjargal, Solongo; Huang, Yun; Wang, Yanxin J; Petersson, E James

    2014-02-01

    Thioamides can be used as photoswitches, as reporters of local environment, as inhibitors of enzymes, and as fluorescence quenchers. We have recently demonstrated the incorporation of thioamides into polypeptides and proteins using native chemical ligation (NCL). In this protocol, we describe procedures for the synthesis of a thioamide precursor and an NCL-ready thioamide-containing peptide using Dawson's N-acyl-benzimidazolinone (Nbz) process. We include a description of the synthesis by NCL of a thioamide-labeled fragment of the neuronal protein α-synuclein. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  16. Boc-SPPS: Compatible Linker for the Synthesis of Peptide o-Aminoanilides.

    Science.gov (United States)

    Weidmann, Joachim; Dimitrijević, Elena; Hoheisel, Jörg D; Dawson, Philip E

    2016-01-15

    A protection strategy is described for the efficient synthesis of peptide o-aminoanilides using in situ neutralization protocols for Boc-SPPS. On-resin protection of Boc-protected aminoacyl o-aminoanilides is achieved with 2-chlorobenzyl chloroformate. Activation through a peptidyl-benzotriazole intermediate allows for facile conversion to peptide-thioesters for use in native chemical ligation. In addition to providing a robust alternative to established thioester resins, as a latent thioester, the peptide o-aminoanilide has broad utility in convergent ligation strategies.

  17. Peptide Macrocycles Featuring a Backbone Secondary Amine: A Convenient Strategy for the Synthesis of Lipidated Cyclic and Bicyclic Peptides on Solid Support

    DEFF Research Database (Denmark)

    Oddo, Alberto; Münzker, Lena; Hansen, Paul Robert

    2015-01-01

    A convenient strategy for the on-resin synthesis of macrocyclic peptides (3- to 13-mers) via intramolecular halide substitution by a diamino acid is described. The method is compatible with standard Fmoc/tBu SPPS and affords a tail-to-side-chain macrocyclic peptide featuring an endocyclic secondary...

  18. Synthesis, characterization, and electrospinning of novel polyaniline-peptide polymers.

    Science.gov (United States)

    Archibong, Edikan; Foster, Alexander; Caldwell, Keirsten; Lita, Adrian; Mochona, Bereket; Mateeva, Nelly

    2016-09-01

    Aniline-peptide (FLDQV, FLDQVC, Dansyl-FLDQV, Dansyl-FLDQVC, and FLDQV-AMC) mixtures underwent oxidative chemical and electrochemical polymerization in excess of aniline. The products of the chemical polymerization were low molecular weight polymers containing more than 70% peptide. Electrochemically polymerized species polyaniline-FLDQV (PANI-FLDQV) consisted mainly of polyaniline units containing about 10% peptide. The solubility of the latter in 1,1,1,3,3,3-hexafluoro-2-propanol (HFP) was similar to the camphorsulfonic acid (CSA) doped emeraldine base (PANI-CSA) solubility, however the weight composition of the electrospun fibers produced from the two polymers was significantly different. 2D 1 H- 13 C HSQC analyses were employed to analyze the binding between the aniline and peptide moieties. Binding of peptide to polyaniline is reflected by the appearance of extra cross-peaks which display line broadening between the free polyaniline and the free pentapeptide. Peptides may be chemically bonded to the polymer molecules, but they may also act as doping agents to the nitrogen atoms via hydrogen bonding.

  19. Synthesis and evaluation of phenylalanine-derived trifluoromethyl ketones for peptide-based oxidation catalysis.

    Science.gov (United States)

    Featherston, Aaron L; Miller, Scott J

    2016-10-15

    We report the synthesis of phenylalanine-derived trifluoromethyl ketones for the in situ generation of dioxiranes for the purpose of oxidation catalysis. The key features of this synthesis include the use of a masked ketone strategy and a Negishi cross-coupling to access the parent amino acid. The derivatives can be readily incorporated into a peptide for use in oxidation chemistry and exhibit good stability and reactivity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Total synthesis, structure, and oral absorption of a thiazole cyclic peptide, sanguinamide A

    DEFF Research Database (Denmark)

    Nielsen, Daniel S; Hoang, Huy N; Lohman, Rink-Jan

    2012-01-01

    The first total synthesis and three-dimensional solution structure are reported for sanguinamide A, a thiazole-containing cyclic peptide from the sea slug H. sanguineus. Solution phase fragment synthesis, solid phase fragment assembly, and solution macrocyclization were combined to give (1) in 10......% yield. Spectral properties were identical for the natural product, requiring revision of its structure from (2) to (1). Intramolecular transannular hydrogen bonds help to bury polar atoms, which enables oral absorption from the gut....

  1. Templated Synthesis of Peptide Nucleic Acids via Sequence-Selective Base-Filling Reactions

    OpenAIRE

    Heemstra, Jennifer M.; Liu, David R.

    2009-01-01

    The templated synthesis of nucleic acids has previously been achieved through the backbone ligation of preformed nucleotide monomers or oligomers. In contrast, here we demonstrate templated nucleic acid synthesis using a base-filling approach in which individual bases are added to abasic sites of a peptide nucleic acid (PNA). Because nucleobase substrates in this approach are not self-reactive, a base-filling approach may reduce the formation of nontemplated reaction products. Using either re...

  2. Synthesis and secretion of glucagon-like peptide-1 by fetal rat intestinal cells in culture.

    Science.gov (United States)

    Jackson Huang, T H; Brubaker, P L

    1995-07-01

    Secretion of the intestinal proglucagon-derived peptides (PGDPs) including the incretin glucagon-like peptide-1 (GLP-1) is regulated, at least in part, by the duodenal hormone glucose-dependent insulinotropic peptide (GIP) through a protein kinase (PK) A-dependent pathway. It has been demonstrated that the activation of PKA increases the synthesis of some intestinal PGDPs, particularly the glucagon-like immunoreactive (GLI) peptides glicentin and oxyntomodulin. However, the effects of GIP on GLI and GLP-1 synthesis are not known. Fetal rat intestinal cells in culture were therefore treated for up to 24 h with 5MM: dbcAMP or 10(-6) M: GIP and the changes in glicentin, oxyntomodulin, GLP-1(x-37) and GLP-1(x-36NH2) secretion and synthesis were examined by RIA and HPLC. Both dbcAMP and GIP increased the acute (2 h; to 224±21 and 256±20% of controls, respectively,P<0.001) and chronic (24 h; to 230±22 and 130±6% of controls, respectively,P<0.001) secretion of intestinal PGDPs. In contrast, the total culture content of PGDPs was increased only after 24 h of incubation (to 156±15 and 125±7% of controls for dbcAMP and GIP, respectively,P<0.01). HPLC analysis confirmed that the intestinal cultures produced the GLI peptides glicentin and oxyntomodulin, as well as the biologically active forms of GLP-1, GLP-7(7-37) and GLP-1(7-36NH2). The relative proportion of these peptides was not altered by treatment with dbcAMP or GIP. Thus, in addition to its effects on GLP-1 release from the rat intestine, GIP appears to be an important regulator of the synthesis of this insulinotropic peptide.

  3. Peptide Bond Synthesis by a Mechanism Involving an Enzymatic Reaction and a Subsequent Chemical Reaction.

    Science.gov (United States)

    Abe, Tomoko; Hashimoto, Yoshiteru; Zhuang, Ye; Ge, Yin; Kumano, Takuto; Kobayashi, Michihiko

    2016-01-22

    We recently reported that an amide bond is unexpectedly formed by an acyl-CoA synthetase (which catalyzes the formation of a carbon-sulfur bond) when a suitable acid and l-cysteine are used as substrates. DltA, which is homologous to the adenylation domain of nonribosomal peptide synthetase, belongs to the same superfamily of adenylate-forming enzymes, which includes many kinds of enzymes, including the acyl-CoA synthetases. Here, we demonstrate that DltA synthesizes not only N-(d-alanyl)-l-cysteine (a dipeptide) but also various oligopeptides. We propose that this enzyme catalyzes peptide synthesis by the following unprecedented mechanism: (i) the formation of S-acyl-l-cysteine as an intermediate via its "enzymatic activity" and (ii) subsequent "chemical" S → N acyl transfer in the intermediate, resulting in peptide formation. Step ii is identical to the corresponding reaction in native chemical ligation, a method of chemical peptide synthesis, whereas step i is not. To the best of our knowledge, our discovery of this peptide synthesis mechanism involving an enzymatic reaction and a subsequent chemical reaction is the first such one to be reported. This new process yields peptides without the use of a thioesterified fragment, which is required in native chemical ligation. Together with these findings, the same mechanism-dependent formation of N-acyl compounds by other members of the above-mentioned superfamily demonstrated that all members most likely form peptide/amide compounds by using this novel mechanism. Each member enzyme acts on a specific substrate; thus, not only the corresponding peptides but also new types of amide compounds can be formed. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Customized Peptide Biomaterial Synthesis via an Environment-Reliant Auto-Programmer Stigmergic Approach.

    Science.gov (United States)

    Badhe, Ravindra V; Kumar, Pradeep; Choonara, Yahya E; Marimuthu, Thashree; du Toit, Lisa C; Bijukumar, Divya; Chejara, Dharmesh R; Mabrouk, Mostafa; Pillay, Viness

    2018-04-16

    Stigmergy, a form of self-organization, was employed here to engineer a self-organizing peptide capable of forming a nano- or micro-structure and that can potentially be used in various drug delivery and biomedical applications. These self-assembling peptides exhibit several desirable qualities for drug delivery, tissue engineering, cosmetics, antibiotics, food science, and biomedical surface engineering. In this study, peptide biomaterial synthesis was carried out using an environment-reliant auto-programmer stigmergic approach. A model protein, α-gliadin (31, 36, and 38 kD), was forced to attain a primary structure with free –SH groups and broken down enzymatically into smaller fragments using chymotrypsin. This breakdown was carried out at different environment conditions (37 and 50 °C), and the fragments were allowed to self-organize at these temperatures. The new peptides so formed diverged according to the environmental conditions. Interestingly, two peptides (with molecular weights of 13.8 and 11.8 kD) were isolated when the reaction temperature was maintained at 50 °C, while four peptides with molecular weights of 54, 51, 13.8, and 12.8 kD were obtained when the reaction was conducted at 37 °C. Thus, at a higher temperature (50 °C), the peptides formed, compared to the original protein, had lower molecular weights, whereas, at a lower temperature (37 °C), two peptides had higher molecular weights and two had lower molecular weights.

  5. Solid-phase synthesis of head and tail bis-acridinylated peptides

    Czech Academy of Sciences Publication Activity Database

    Šebestík, Jaroslav; Matějka, P.; Hlaváček, Jan; Stibor, I.

    2004-01-01

    Roč. 45, č. 6 (2004), s. 1203-1205 ISSN 0040-4039 R&D Projects: GA ČR GA203/02/1379 Institutional research plan: CEZ:AV0Z4055905 Keywords : 9-amino acridine * solid phase synthesis * head and tail peptide conjugates Subject RIV: CC - Organic Chemistry Impact factor: 2.484, year: 2004

  6. Process design for enzymatic peptide synthesis in near-anhydrous organic media

    NARCIS (Netherlands)

    Vossenberg, P.; Beeftink, H.H.; Stuart, M.A.C.; Tramper, J.

    2013-01-01

    This work is a case study on a process design for enzymatic peptide synthesis, which is based on and inspired by previously established data about the Alcalase-catalyzed coupling of an amino acid amide and a chemically synthesized activated N-protected amino acid carbamoylmethyl ester in

  7. Synthesis of water-soluble scaffolds for peptide cyclization, labeling, and ligation

    NARCIS (Netherlands)

    Smeenk, L.E.J.; Dailly, N.; Hiemstra, H.; van Maarseveen, J.H.; Timmerman, P.

    2012-01-01

    The synthesis and applications of water-soluble scaffolds that conformationally constrain side chain unprotected linear peptides containing two cysteines are described. These scaffolds contain a functionality with orthogonal reactivity to be used for labeling and ligation. This is illustrated by the

  8. Multienzyme Modification of Hemp Protein for Functional Peptides Synthesis

    Directory of Open Access Journals (Sweden)

    Ranjana Das

    2015-01-01

    Full Text Available Functional foods and nutraceuticals are of special importance, particularly for their impact on human health and prevention of certain chronic diseases. Consequently, the production and properties of bioactive peptides have received an increasing scientific interest over past few years. Present work intends to compare the competence of metalloendopeptidases (“Protease N” and “Protease A” with papain for getting functional peptides from hemp seed meal, which is an obligatory waste of hemp fiber production industry. As a measure of the functional potential hemp protein hydrolysates were analyzed for their antiradical properties in DPPH system. “Protease N” modified protein hydrolysate exhibited comparatively superior radical scavenging activity in DPPH system. Overall findings represent the importance of “Protease N,” as endopeptidase in getting peptides of good antiradical properties from various protein sources.

  9. Sequence-Specific β-Peptide Synthesis by a Rotaxane-Based Molecular Machine.

    Science.gov (United States)

    De Bo, Guillaume; Gall, Malcolm A Y; Kitching, Matthew O; Kuschel, Sonja; Leigh, David A; Tetlow, Daniel J; Ward, John W

    2017-08-09

    We report on the synthesis and operation of a three-barrier, rotaxane-based, artificial molecular machine capable of sequence-specific β-homo (β 3 ) peptide synthesis. The machine utilizes nonproteinogenic β 3 -amino acids, a class of amino acids not generally accepted by the ribosome, particularly consecutively. Successful operation of the machine via native chemical ligation (NCL) demonstrates that even challenging 15- and 19-membered ligation transition states are suitable for information translation using this artificial molecular machine. The peptide-bond-forming catalyst region can be removed from the transcribed peptide by peptidases, artificial and biomachines working in concert to generate a product that cannot be made by either machine alone.

  10. Synthesis of peptide derivatives of aspirin and their antibiogram ...

    African Journals Online (AJOL)

    Peptide derivatives of Aspirin (1 to 8) were synthesized by using Ac2O/AcOH reaction with Salicyclic acid. Aspirin was coupled with amino acid amide and dipeptide amide and tripeptide amide using its p-nitro phenyl (NP) ester. The ester (Aspirin–ONP) was prepared using p-nitro phenol and DCC in EtOAc and was ...

  11. Multi-line split DNA synthesis: a novel combinatorial method to make high quality peptide libraries

    Directory of Open Access Journals (Sweden)

    Ueno Shingo

    2004-09-01

    Full Text Available Abstract Background We developed a method to make a various high quality random peptide libraries for evolutionary protein engineering based on a combinatorial DNA synthesis. Results A split synthesis in codon units was performed with mixtures of bases optimally designed by using a Genetic Algorithm program. It required only standard DNA synthetic reagents and standard DNA synthesizers in three lines. This multi-line split DNA synthesis (MLSDS is simply realized by adding a mix-and-split process to normal DNA synthesis protocol. Superiority of MLSDS method over other methods was shown. We demonstrated the synthesis of oligonucleotide libraries with 1016 diversity, and the construction of a library with random sequence coding 120 amino acids containing few stop codons. Conclusions Owing to the flexibility of the MLSDS method, it will be able to design various "rational" libraries by using bioinformatics databases.

  12. Solid Phase Peptide Synthesis of Antimicrobial Peptides for cell Binding Studies: Characterization Using Mass Spectrometry

    National Research Council Canada - National Science Library

    Vouros, Paul

    2002-01-01

    ...) in order to determine their anti-microbial activity. To expedite this goal, mass spectrometry was used to identify products of the solid phase synthesis and thereby optimize synthetic conditions...

  13. Design and synthesis of substrate analogue inhibitors of peptide deformylase.

    Science.gov (United States)

    Meinnel, T; Patiny, L; Ragusa, S; Blanquet, S

    1999-04-06

    Series of substrates derivatives of peptide deformylase were systematically synthesized and studied for their capacities to undergo hydrolysis. Data analysis indicated the requirement for a hydrophobic first side chain and for at least two main chain carbonyl groups in the substrate. For instance, Fo-Met-OCH3 and Fo-Nle-OCH3 were the minimal substrates of peptide deformylase obtained in this study, while positively charged Fo-Nle-ArgNH2 was the most efficient substrate (kcat/Km = 4.5 x 10(5) M-1.s-1). On the basis of this knowledge, 3-mercapto-2-benzylpropanoylglycine (thiorphan), a known inhibitor of thermolysin, could be predicted and further shown to inhibit the deformylation reaction. The inhibition by this compound was competitive and proved to depend on the hydrophobicity at the P1' position. Spectroscopic evidence that the sulfur group of thiorphan binds next to the active site metal ion on the enzyme could be obtained. Consequently, a small thiopseudopeptide derived from Fo-Nle-OCH3 was designed and synthesized. This compound behaved as a competitive inhibitor of peptide deformylase with KI = 52 +/- 5 microM. Introduction of a positive charge to this thiopeptide via addition of an arginine at P2' improved the inhibition constant up to 2.5 +/- 0.5 microM, a value 4 orders of magnitude smaller than that of the starting inhibitors. Evidence that this inhibitor, imino[(5-methoxy-5-oxo-4-[[2-(sulfanylmethyl)hexanoyl]amino]pentyl )am ino]methanamine, binds inside the active site cavity of peptide deformylase, while keeping intact the 3D fold of the protein, was provided by NMR. A fingerprint of the interaction of the inhibitor with the residues of the enzyme was obtained.

  14. Plant natriuretic peptides control of synthesis and systemic effects

    KAUST Repository

    Wang, Yuhua

    2011-10-01

    Plant natriuretic peptides (PNPs) are signaling molecules that are secreted into the apoplast particularly under conditions of biotic and abiotic stress. At the local level, PNPs modulate their own expression via feed forward and feedback loops to enable tuning of the response at the transcript and protein level and to prevent overexpression. PNPs also employ a systemic signal, possibly electrical, to rapidly alter photosynthesis and respiration not only in treated leaves but also in upper and lower leaves thereby modulating and integrating physiological responses at the level of the whole plant. © 2011 Landes Bioscience.

  15. A rapid and clean synthetic approach to cyclic peptides via micro-flow peptide chain elongation and photochemical cyclization: synthesis of a cyclic RGD peptide.

    Science.gov (United States)

    Mifune, Yuto; Nakamura, Hiroyuki; Fuse, Shinichiro

    2016-11-29

    A cyclic RGD peptide was efficiently synthesized based on micro-flow, triphosgene-mediated peptide chain elongation and micro-flow photochemical macrolactamization. Our approach enabled a rapid (amidation for peptide chain elongation peptide.

  16. Highly efficient synthetic method onpyroacm resin using the boc SPPS protocol for C-terminal cysteine peptide synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Juvekar, Vinayak; Kim, Kang Tae; Gong, Young Dae [Innovative Drug Library Research Center, Dept. of Chemistry, College of Science, Dongguk University, Seoul (Korea, Republic of)

    2017-01-15

    A very effective process on Pyroacm resin was developed for solid-phase peptide synthesis (SPPS) of C-terminal cysteine and cysteine ester peptides. The process uses cysteine side chain anchoring to the Pyroacm resin and the Boc protocol for SPPS. The Pyroacm resin showed remarkable stability under standard trifluoromethanesulfonic acid (TFMSA) cleavage condition. TFMSA cleavage of protecting groups generates a peptide-linked resin, which can be subjected to peptide modification reactions. Finally, the peptide can be cleaved from the resin using methoxycarbonylsulfenyl chloride. The utility of this protocol was demonstrated by its applications to the synthesis of model peptides, key intermediates in the preparation of natural products riparin 1.2 and a-factor.

  17. Optimization of synthesis and quality control procedures for the preparation of 18F-labelled peptides

    International Nuclear Information System (INIS)

    Amartey, J.K.

    2002-01-01

    human cancer cell line in a dose dependent manner as expected. The biodistribution showed that the [ 18 F]-RC-160 bound to tumour xenograft in nude mice. The main objective of the project was to optimize reaction conditions and quality control procedures for prosthetic labelling of peptides. Hence the aims of the project were to: improve fluorination of prosthetic group such as fluorobenzoate, synthesis and isolation of the succinimidyl activated ester of the prosthetic group and reaction conditions to couple the activated ester to a model chemotactic peptide, and to develop an isolation method for the peptide conjugate; perform in vitro and in vivo experiments to ascertain the biological activity of the conjugate; apply the methods and techniques developed to label another biologically active peptide and evaluate its potential application as a cancer detection agent. (author)

  18. Design, synthesis, and functional testing of recombinant cell penetrating peptides

    Science.gov (United States)

    Widyaningtyas, S. T.; Soebandrio, A.; Ibrahim, F.; Bela, B.

    2017-08-01

    Cell penetrating peptides (CPP) are one of the most attractive DNA delivery systems currently in development. In this research, in silico CPP development was performed based on a literature study to look for peptides that induce endosome escape, have the ability to bind DNA, and pass through cell membranes and/or nuclear membranes with a final goal of creating a new CPP to be used as a DNA delivery system. We report herein the successful isolation of three candidate CPP molecules, which have all been successfully expressed and purified by NiNTA. One of the determinants of CPP success as a DNA carrier is the ability of the CPP to bind and protect DNA from the effects of nucleases. The DNA binding test results show that all three CPPs can bind to DNA and protect it from the effects of serum nucleases. These three CPP candidates designed in silico and synthesized in the prokaryote system are eligible candidates for further testing of their ability to deliver DNA in vitro and in vivo.

  19. One-pot native chemical ligation of peptide hydrazides enables total synthesis of modified histones.

    Science.gov (United States)

    Li, Jiabin; Li, Yuanyuan; He, Qiaoqiao; Li, Yiming; Li, Haitao; Liu, Lei

    2014-08-07

    One of the rising demands in the field of protein chemical synthesis is the development of facile strategies that yield the protein in workable quantities and homogeneity, with fewer handling steps. Although the native chemical ligation of peptide hydrazides has recently been shown to be useful for the chemical synthesis of proteins carrying acid-sensitive modification groups, previous hydrazide-based protein synthesis studies have used sequential ligation strategies. Here, we report a practical method for a "one-pot" native chemical ligation of peptide hydrazides that would circumvent the need for the isolation of the intermediate products. This method employed a fast and selective arylboronate oxidation reaction mediated by H2O2, which draws attention to the potential applications of the thus far under-exploited boron-based functionalities in protein chemical synthesis. To demonstrate the practicality and efficiency of the new one-pot method, we report its application to a scalable total synthesis of modified histones (with five analogues of H3 and H4 as examples) on a multi-milligram scale, with good homogeneity.

  20. Convenient and Scalable Synthesis of Fmoc-Protected Peptide Nucleic Acid Backbone

    Directory of Open Access Journals (Sweden)

    Trevor A. Feagin

    2012-01-01

    Full Text Available The peptide nucleic acid backbone Fmoc-AEG-OBn has been synthesized via a scalable and cost-effective route. Ethylenediamine is mono-Boc protected, then alkylated with benzyl bromoacetate. The Boc group is removed and replaced with an Fmoc group. The synthesis was performed starting with 50 g of Boc anhydride to give 31 g of product in 32% overall yield. The Fmoc-protected PNA backbone is a key intermediate in the synthesis of nucleobase-modified PNA monomers. Thus, improved access to this molecule is anticipated to facilitate future investigations into the chemical properties and applications of nucleobase-modified PNA.

  1. Customized Peptide Biomaterial Synthesis via an Environment-Reliant Auto-Programmer Stigmergic Approach

    Directory of Open Access Journals (Sweden)

    Ravindra V. Badhe

    2018-04-01

    Full Text Available Stigmergy, a form of self-organization, was employed here to engineer a self-organizing peptide capable of forming a nano- or micro-structure and that can potentially be used in various drug delivery and biomedical applications. These self-assembling peptides exhibit several desirable qualities for drug delivery, tissue engineering, cosmetics, antibiotics, food science, and biomedical surface engineering. In this study, peptide biomaterial synthesis was carried out using an environment-reliant auto-programmer stigmergic approach. A model protein, α-gliadin (31, 36, and 38 kD, was forced to attain a primary structure with free –SH groups and broken down enzymatically into smaller fragments using chymotrypsin. This breakdown was carried out at different environment conditions (37 and 50 °C, and the fragments were allowed to self-organize at these temperatures. The new peptides so formed diverged according to the environmental conditions. Interestingly, two peptides (with molecular weights of 13.8 and 11.8 kD were isolated when the reaction temperature was maintained at 50 °C, while four peptides with molecular weights of 54, 51, 13.8, and 12.8 kD were obtained when the reaction was conducted at 37 °C. Thus, at a higher temperature (50 °C, the peptides formed, compared to the original protein, had lower molecular weights, whereas, at a lower temperature (37 °C, two peptides had higher molecular weights and two had lower molecular weights.

  2. Dimeric Building Blocks for Solid-Phase Synthesis of α-Peptide-β-Peptoid Chimeras

    DEFF Research Database (Denmark)

    Seigan, Gitte Bonke; Vedel, Line; Matthias, Witt,

    2008-01-01

    Recently, a novel type of antimicrobial and proteolytically stable peptidomimetic oligomers having an α-peptide-β-peptoid chimeric backbone was reported. The present paper describes efficient protocols for the preparation of a wide range of dimeric building blocks, displaying different types...... of side-chains, for use in solid-phase synthesis (SPS) of libraries of this type of oligomers. The β-peptoid monomers were obtained by microwave-assisted aza-Michael additions to acrylic esters. Subsequent solution-phase peptide coupling with suitably protected α-amino acids afforded dimeric intermediates....... Even sluggish peptide couplings, involving sterically hindered N-alkyl-β-alanines or amino acids with bulky side-chains, gave high yields on multigram-scale when using microwave (MW) irradiation. Protecting group and side-chain manipulations were performed as one-pot solution-phase procedures to afford...

  3. 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.

  4. Development of a method for environmentally friendly chemical peptide synthesis in water using water-dispersible amino acid nanoparticles

    Directory of Open Access Journals (Sweden)

    Fukumori Yoshinobu

    2011-08-01

    Full Text Available Abstract Due to the vast importance of peptides in biological processes, there is an escalating need for synthetic peptides to be used in a wide variety of applications. However, the consumption of organic solvent is extremely large in chemical peptide syntheses because of the multiple condensation steps in organic solvents. That is, the current synthesis method is not environmentally friendly. From the viewpoint of green sustainable chemistry, we focused on developing an organic solvent-free synthetic method using water, an environmentally friendly solvent. Here we described in-water synthesis technology using water-dispersible protected amino acids.

  5. One-pot synthesis of water soluble iron nanoparticles using rationally-designed peptides and ligand release.

    Science.gov (United States)

    Papst, Stefanie; Cheong, Soshan; Banholzer, Moritz J; Brimble, Margaret A; Williams, David E; Tilley, Richard D

    2013-05-18

    Herein we report the rational design of new phosphopeptides for control of nucleation, growth and aggregation of water-soluble, superparamagnetic iron-iron oxide core-shell nanoparticles. The use of the designed peptides enables a one-pot synthesis that avoids utilizing unstable or toxic iron precursors, organic solvents, and the need for exchange of capping agent after synthesis of the NPs.

  6. Synthesis of a Natural Product-Like Compound Collection through Oxidative Cleavage and Cyclization of Linear Peptides

    DEFF Research Database (Denmark)

    Petersen, Rico; Le Quement, Sebastian Thordal; Nielsen, Thomas Eiland

    2014-01-01

    Massive efforts in molecular library synthesis have strived for the development of synthesis methodology which systematically delivers natural product-like compounds of high spatial complexity. Herein, we present a conceptually simple approach that builds on the power of solid-phase peptide...... synthesis to assemble precursor peptides (oligomers) designed to undergo oxidative cascade reactions. By harnessing the structural side-chain diversity and inherent stereochemical features offered by readily available amino acids (monomers), a proof-of-concept collection of 54 skeletally and stereochem......- ically diverse compounds was generated, and selected com- pounds were elaborated into isoform-selective metalloprotease inhibitors...

  7. Synthesis of a Natural Product-Like Compound Collection through Oxidative Cleavage and Cyclization of Linear Peptides

    DEFF Research Database (Denmark)

    Petersen, Rico; Le Quement, Sebastian Thordal; Nielsen, Thomas Eiland

    2014-01-01

    Massive efforts in molecular library synthesis have strived for the development of synthesis methodology which systematically delivers natural product-like compounds of high spatial complexity. Herein, we present a conceptually simple approach that builds on the power of solid-phase peptide...... synthesis to assemble precursor peptides (oligomers) designed to undergo oxidative cascade reactions. By harnessing the structural side-chain diversity and inherent stereochemical features offered by readily available amino acids (monomers), a proof-of-concept collection of 54 skeletally and stereochem......- ically diverse compounds was generated, and selected com- pounds were elaborated into isoform-selective metalloprotease inhibitors....

  8. Fmoc-based peptide thioester synthesis with self-purifying effect: heading to native chemical ligation in parallel formats.

    Science.gov (United States)

    Thomas, Franziska

    2013-03-01

    The chemical synthesis of proteins has facilitated functional studies of proteins due to the site-specific incorporation of post-translational modifications, labels, and non-proteinogenic amino acids. Moreover, native chemical ligation provides facile access to proteins by chemical means. However, the application of the native chemical ligation reaction in the synthesis of parallel formats such as protein arrays has been complicated because of the often cumbersome and time-consuming synthesis of the required peptide thioesters. An Fmoc-based peptide thioester synthesis with self-purification on the sulfonamide 'safety-catch' linker widens this bottleneck because HPLC purification can be avoided. The method is based on an on-resin cyclization-thiolysis reaction sequence. A macrocyclization via the N-terminus of the full-length peptide followed by a thiolytic C-terminal ring opening allows selective detachment of the truncation products and the full-length peptide. A brief overview of the chemical aspects of this method is provided including the optimization steps and the automation process. Furthermore, the application of the cyclization-thiolysis approach combined with the native chemical ligation reaction in the parallel synthesis of a library of 16 SH3-domain variants of SHO1 in yeast is described, demonstrating the value of this new technique for the chemical synthesis of protein arrays. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.

  9. Liquid-phase synthesis of bridged peptides using olefin metathesis of a protected peptide with a long aliphatic chain anchor.

    Science.gov (United States)

    Aihara, Keisuke; Komiya, Chiaki; Shigenaga, Akira; Inokuma, Tsubasa; Takahashi, Daisuke; Otaka, Akira

    2015-02-06

    Bridged peptides including stapled peptides are attractive tools for regulating protein-protein interactions (PPIs). An effective synthetic methodology in a heterogeneous system for the preparation of these peptides using olefin metathesis and hydrogenation of protected peptides with a long aliphatic chain anchor is reported.

  10. Uniting polypeptides with sequence-designed peptides: synthesis and assembly of poly(gamma-benzyl L-glutamate)-b-coiled-coil peptide copolymers.

    Science.gov (United States)

    Marsden, Hana Robson; Handgraaf, Jan-Willem; Nudelman, Fabio; Sommerdijk, Nico A J M; Kros, Alexander

    2010-02-24

    A new class of peptide has been created, polypeptide-b-designed peptides, which unites the useful qualities of the two constituent peptide types. We demonstrate the synthesis and self-assembly possibilities of this class of peptide chimera with a series of amphiphilic polypeptide-b-designed peptides in which the hydrophobic block is poly(gamma-benzyl l-glutamate) (PBLG) and the hydrophilic block is a coiled-coil forming peptide (denoted E). The synthetic approach was to synthesize the coiled-coil forming peptide on the solid phase, followed by the ring-opening polymerization of gamma-benzyl l-glutamate N-carboxyanhydride, initiated from the N-terminal amine of the peptide E on the solid support. The polypeptide-b-peptide was then cleaved from the resin, requiring no further purification. Peptide E contains 22 amino acids, while the average length of the PBLG block ranged from 36 to 250 residues. This new class of peptide was applied to create a modular system, which relied on juxtaposing the properties of the component peptide types, namely the broad size range and structure-inducing characteristics of the polypeptide PBLG blocks, and the complex functionality of the sequence-designed peptide. Specifically, the different PBLG block lengths could be connected noncovalently with various hydrophilic blocks via the specific coiled-coil folding of E with K or K-poly(ethylene glycol), where K is a peptide of complementary amino acid sequence to E. In this way, nanostructures could be formed in water at neutral pH over the entire compositional range, which has not been demonstrated previously with such large PBLG blocks. It was found that the size, morphology (polymersomes or bicelles), and surface functionality could be specified by combining the appropriate modular building blocks. The self-assembled structures were characterized by dynamic light scattering, circular dichroism, scanning electron microscopy, cryogenic-transmission electron microscopy, fluorescence

  11. Orthogonal ring-closing alkyne and olefin metathesis for the synthesis of small GTPase-targeting bicyclic peptides.

    Science.gov (United States)

    Cromm, Philipp M; Schaubach, Sebastian; Spiegel, Jochen; Fürstner, Alois; Grossmann, Tom N; Waldmann, Herbert

    2016-04-14

    Bicyclic peptides are promising scaffolds for the development of inhibitors of biological targets that proved intractable by typical small molecules. So far, access to bioactive bicyclic peptide architectures is limited due to a lack of appropriate orthogonal ring-closing reactions. Here, we report chemically orthogonal ring-closing olefin (RCM) and alkyne metathesis (RCAM), which enable an efficient chemo- and regioselective synthesis of complex bicyclic peptide scaffolds with variable macrocycle geometries. We also demonstrate that the formed alkyne macrocycle can be functionalized subsequently. The orthogonal RCM/RCAM system was successfully used to evolve a monocyclic peptide inhibitor of the small GTPase Rab8 into a bicyclic ligand. This modified peptide shows the highest affinity for an activated Rab GTPase that has been reported so far. The RCM/RCAM-based formation of bicyclic peptides provides novel opportunities for the design of bioactive scaffolds suitable for the modulation of challenging protein targets.

  12. Phospholyl(borane) Amino Acids and Peptides: Stereoselective Synthesis and Fluorescent Properties with Large Stokes Shift.

    Science.gov (United States)

    Arribat, Mathieu; Rémond, Emmanuelle; Clément, Sébastien; Lee, Arie Van Der; Cavelier, Florine

    2018-01-24

    The synthesis of phospholyl(borane) amino acids was stereoselectively achieved by reaction of phospholide anion with iodo α-amino ester derived from l-aspartic acid or l-serine, followed by in situ complexation with borane. Phospholyl(borane) amino acids are easy to store and can be subjected to direct transformation into the corresponding free phospholyl, gold complex, oxide or sulfur derivatives as well as phospholinium salts, thus offering a variety of side chains. After selective deprotection of carboxylic function or amine, C- or N- peptide coupling with an alanine moiety proved the possible incorporation into peptides. Such phospholyl amino acid and peptide derivatives exhibit fluorescent properties with a large Stokes shift (160 nm) and fluorescence up to 535 nm, depending on the phosphole aromaticity and the chemical environment. These phospholyl(borane) amino acids constitute a new class of unnatural amino acids useful for structure-activities relationship studies and appear to be promising fluorophores for the development of labeled peptides.

  13. Plant antimicrobial peptides snakin-1 and snakin-2: chemical synthesis and insights into the disulfide connectivity.

    Science.gov (United States)

    Harris, Paul W R; Yang, Sung-Hyun; Molina, Antonio; López, Gemma; Middleditch, Martin; Brimble, Margaret A

    2014-04-22

    Antimicrobial peptides and proteins represent an important class of plant defensive compounds against pathogens and provide a rich source of lead compounds in the field of drug discovery. We describe the effective preparation of the cysteine-rich snakin-1 and -2 antimicrobial peptides by using a combination of solid-phase synthesis and native chemical ligation. A subsequent cysteine/cystine mediated oxidative folding to form the six internal disulfide bonds concurrently gave the folded proteins in 40-50 % yield. By comparative evaluation of mass spectrometry, HPLC, biological data and trypsin digest mapping of folded synthetic snakin-2 compared to natural snakin-2, we demonstrated that synthetic snakin-2 possesses full antifungal activity and displayed similar chromatographic behaviour to natural snakin-2. Trypsin digest analysis allowed tentative assignment of three of the purported six disulfide bonds. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Synthesis of relaxin-2 and insulin-like peptide 5 enabled by novel tethering and traceless chemical excision.

    Science.gov (United States)

    Thalluri, Kishore; Kou, Binbin; Yang, Xu; Zaykov, Alexander N; Mayer, John P; Gelfanov, Vasily M; Liu, Fa; DiMarchi, Richard D

    2017-06-01

    This report presents an entirely chemical, general strategy for the synthesis of relaxin-2 and insulin-like peptide 5. Historically, these two peptides have represented two of the more synthetically challenging members of the insulin superfamily. The key synthetic steps involve two sequential oxime ligations to covalently link the individual A-chain and B-chain, followed by disulfide bond formation under aqueous, redox conditions. This is followed by two chemical reactions that employ diketopiperazine cyclization-mediated cleavage and ester hydrolysis to liberate the connecting peptide and the heterodimeric product. This approach avoids the conventional iodine-mediated disulfide bond formation and enzyme-assisted proteolysis to generate biologically active two-chain peptides. This novel synthetic strategy is ideally suited for peptides such as relaxin and insulin-like peptide 5 as they possess methionine and tryptophan that are labile under strong oxidative conditions. Additionally, these peptides possess multiple arginine and lysine residues that preclude the use of trypsin-like enzymes to obtain biologically active hormones. This synthetic methodology is conceivably applicable to other two-chain peptides that contain multiple disulfide bonds. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

  15. Synthesis and characterisation of substrate-based peptides as inhibitors of histone demethylase KDM4C

    DEFF Research Database (Denmark)

    Nielsen, Simon D; Leurs, Ulrike; Bergner, Magnus

    2016-01-01

    The design and synthesis of modified pentapeptides based on a truncated version of the substrate for KDM4C, a histone lysine demethylase (KDM), and investigation of their inhibitory activity at KDM4C is reported. By modifying the lysine residue corresponding to lysine 9 at histone 3 (H3K9), three...... different series of peptides were designed and synthesized. One series contained N-acylated H3K9 and two series introduced triazoles in this position via click chemistry to enable facile variation of headgroups. As the click reaction is compatible with free amino acids this was performed on an azido...

  16. Peptide Synthesis Method and Solid Support for Use in the Method

    DEFF Research Database (Denmark)

    1994-01-01

    A method for the solid-phase synthesis of peptides or proteins in high yield and high purity uses a solid support consisting of a functionalized polystyrene-grafted polymer substrate, the grafted polystyrene chains being substantially non-cross-linked and having a chain molecular weight, not incl...... is immersed in a solution of optionally substituted styrene monomer in an alcohol such as methanol, the volume percentage of styrene in the solution preferably being about 30% v/v, and subjected to gamma irradiation....

  17. Templated synthesis of peptide nucleic acids via sequence-selective base-filling reactions.

    Science.gov (United States)

    Heemstra, Jennifer M; Liu, David R

    2009-08-19

    The templated synthesis of nucleic acids has previously been achieved through the backbone ligation of preformed nucleotide monomers or oligomers. In contrast, here we demonstrate templated nucleic acid synthesis using a base-filling approach in which individual bases are added to abasic sites of a peptide nucleic acid (PNA). Because nucleobase substrates in this approach are not self-reactive, a base-filling approach may reduce the formation of nontemplated reaction products. Using either reductive amination or amine acylation chemistries, we observed efficient and selective addition of each of the four nucleobases to an abasic site in the middle of the PNA strand. We also describe the addition of single nucleobases to the end of a PNA strand through base filling, as well as the tandem addition of two bases to the middle of the PNA strand. These findings represent an experimental foundation for nonenzymatic information transfer through base filling.

  18. Phenylalanine-Rich Peptide Mediated Binding with Graphene Oxide and Bioinspired Synthesis of Silver Nanoparticles for Electrochemical Sensing

    Directory of Open Access Journals (Sweden)

    Li Wang

    2017-02-01

    Full Text Available We demonstrated that a phenylalanine-rich peptide molecule, (FEFEFKFK2, could be used for the biofunctionalization of graphene oxide (GO and the bioinspired synthesis of silver nanoparticles (AgNPs for the creation of functional GO–AgNPs nanohybrids. The successful synthesis of GO–AgNPs nanohybrids was proven by the characterizations of atomic force microscopy, transmission electron microscope, and X-ray photoelectron spectroscopy. The fabricated electrochemical H2O2 sensor based on the synthesized GO–AgNPs nanohybrids showed high performances with a linear detection range 0.02–18 mM and a detection limit of 0.13 μM. The design of graphene-binding peptides is of benefit to the biofunctionalization of graphene-based materials, the synthesis of novel graphene–peptide nanohybrids, and the potential applications of graphene in biomedical fields.

  19. Synthesis and evaluation of amphiphilic peptides as nanostructures and drug delivery tools

    Science.gov (United States)

    Sayeh, Naser Ali

    systems can affect the drug delivery efficiency. The result of this work provided insights about optimizing the amphiphilic cyclic-linear trizaolyl peptides can be used to design compounds with more efficient drug delivery capabilities. Chapter 3. MANUSCRIPT II. The objective of this Chapter was to synthesize a different series of amphiphilic peptides for different objectives. First, the amphiphilic trizaolyl peptides in Chapter I were systematically modified by increasing the number of arginine and tryptophan sequence in cyclic and linear peptides. The rationale for the modification was to enhance the possibility of interaction with the cell membrane and therefore improving the cellular uptake process. Moreover, a new class of amphiphilic peptides consist of tryptophan and glutamic acid were conjugated with a peptide containing arginine and lysine residues using Fmoc chemistry. These peptides have an amide bond that generates more flexibility compared to a triazole ring. The chemical and biological properties will be evaluated in future and compared with amphiphilic triazolyl peptides. Finally, additional fatty acids with different length chains were conjugated with positively charged peptides to be evaluated as antibacterial agents. Stearic acid (C16) and myristic acid (C14) were conjugated with a peptides consisting of arginine azide and lysine amino acids to enhance the antibacterial activity. In summary, the work in this dissertation provided insights about the synthesis and characterization of a new class of amphiphilic triazolyl peptides as drug delivery carriers and amphiphilic peptides as antibacterial agents. Molecular modeling was used to explain why triazolyl peptides were unable to enhance the delivery of small molecule drugs compared to the previously synthesized cyclic peptides [WR]4 (Chapter 2) Modification of synthesized peptides in Chapter 1, by addition of more positively charged amino acids or reducing the rigidity by incorporating amide bonds instead

  20. Structure-Based Design and Synthesis of Potent Cyclic Peptides Inhibiting the YAP-TEAD Protein-Protein Interaction.

    Science.gov (United States)

    Zhang, Zhisen; Lin, Zhaohu; Zhou, Zheng; Shen, Hong C; Yan, S Frank; Mayweg, Alexander V; Xu, Zhiheng; Qin, Ning; Wong, Jason C; Zhang, Zhenshan; Rong, Yiping; Fry, David C; Hu, Taishan

    2014-09-11

    The YAP-TEAD protein-protein interaction (PPI) mediates the oncogenic function of YAP, and inhibitors of this PPI have potential usage in treatment of YAP-involved cancers. Here we report the design and synthesis of potent cyclic peptide inhibitors of the YAP-TEAD interaction. A truncation study of YAP interface 3 peptide identified YAP(84-100) as a weak peptide inhibitor (IC50 = 37 μM), and an alanine scan revealed a beneficial mutation, D94A. Subsequent replacement of a native cation-π interaction with an optimized disulfide bridge for conformational constraint and synergistic effect between macrocyclization and modification at positions 91 and 93 greatly boosted inhibitory activity. Peptide 17 was identified with an IC50 of 25 nM, and the binding affinity (K d = 15 nM) of this 17mer peptide to TEAD1 proved to be stronger than YAP(50-171) (K d = 40 nM).

  1. peptide

    Indian Academy of Sciences (India)

    Prakash

    The effects on memory formation and cognitive abilities due to injection of amyloid fragments into the brain have been very inconsistent until now. It has been ... determining the molecular basis of the recognition and assembly processes fostering amyloid-fibril formation is a very complicated task. Moreover, the synthesis of ...

  2. Screening of activators and inhibitors of nuclear protein synthesis using labeled compounds

    International Nuclear Information System (INIS)

    Saitmuratova, O.H.

    2004-01-01

    Full text: With the purpose of definition of physiological activity of some known and yet not investigated natural and synthetic compounds (only 40 compounds) their action on protein synthesis ability (PSA) of nucleus of not sharing cells of a brain of rabbits with use of the marked amino acid - C 14 -lysine has been investigated. As a result of our researches activators of non ribosomal synthesis of protein are revealed: N-(β-chlorethyl)-decahydroquinoline, licorine, lupinine, anabasine hydrochloride, peptides: enkephalin, epitalanine, ACTH 4-7 , proteinkinase C, nitrocel, benzolaminopurine - synthetic cytokinin and inhibitors: cocaine, strychnine, aminazine, venom of a cobra snake, indolyl acetic acid, lectin like proteins, extensin like proteins, polyprenol, nitroglycerine. These received results can be used for the decision of the following problems: - Regulation of biosynthesis of the certain kinds of proteins; - Definition of a functional role of studying proteins; - he classification of studying compounds on activity for research of the certain processes in a cellular level

  3. Pyroacm Resin: An Acetamidomethyl Derived Resin for Solid Phase Synthesis of Peptides through Side Chain Anchoring of C-Terminal Cysteine Residues.

    Science.gov (United States)

    Juvekar, Vinayak; Gong, Young Dae

    2016-02-19

    The design, synthesis and utilization of an efficient acetamidomethyl derived resin for the peptide synthesis is presented using established Fmoc and Boc protocols via side chain anchoring. Cleavage of the target peptide from the resin is performed using carboxymethylsulfenyl chloride under mild conditions which gave in situ thiol-sulfenyl protection of the cysteine residues. The utility of the resin is successfully demonstrated through applications to the syntheses of model peptides and natural products Riparin 1.1 and Riparin 1.2.

  4. Phosphorylation in vivo of non-ribosomal proteins from native 40 S ribosomal particles of Krebs II mouse ascites-tumour cells

    DEFF Research Database (Denmark)

    Schuck, J; Reichert, G; Issinger, O G

    1981-01-01

    Four non-ribosomal proteins from native 40 S ribosomal subunits with mol.wts. of 110 000, 84 000, 68 000 and 26 000 were phosphorylated in vivo when ascites cells were incubated in the presence of [32P]Pi. The 110 000-, 84 000- and 26 000-dalton proteins are identical with phosphorylated products...

  5. Synthesis of linear and cyclic peptide-PEG-lipids for stabilization and targeting of cationic liposome-DNA complexes.

    Science.gov (United States)

    Ewert, Kai K; Kotamraju, Venkata Ramana; Majzoub, Ramsey N; Steffes, Victoria M; Wonder, Emily A; Teesalu, Tambet; Ruoslahti, Erkki; Safinya, Cyrus R

    2016-03-15

    Because nucleic acids (NAs) have immense potential value as therapeutics, the development of safe and effective synthetic NA vectors continues to attract much attention. In vivo applications of NA vectors require stabilized, nanometer-scale particles, but the commonly used approaches of steric stabilization with a polymer coat (e.g., PEGylation; PEG=poly(ethylene glycol)) interfere with attachment to cells, uptake, and endosomal escape. Conjugation of peptides to PEG-lipids can improve cell attachment and uptake for cationic liposome-DNA (CL-DNA) complexes. We present several synthetic approaches to peptide-PEG-lipids and discuss their merits and drawbacks. A lipid-PEG-amine building block served as the common key intermediate in all synthetic routes. Assembling the entire peptide-PEG-lipid by manual solid phase peptide synthesis (employing a lipid-PEG-carboxylic acid) allowed gram-scale synthesis but is mostly applicable to linear peptides connected via their N-terminus. Conjugation via thiol-maleimide or strain-promoted (copper-free) azide-alkyne cycloaddition chemistry is highly amenable to on-demand preparation of peptide-PEG-lipids, and the appropriate PEG-lipid precursors are available in a single chemical step from the lipid-PEG-amine building block. Azide-alkyne cycloaddition is especially suitable for disulfide-bridged peptides such as iRGD (cyclic CRGDKGPDC). Added at 10 mol% of a cationic/neutral lipid mixture, the peptide-PEG-lipids stabilize the size of CL-DNA complexes. They also affect cell attachment and uptake of nanoparticles in a peptide-dependent manner, thereby providing a platform for preparing stabilized, affinity-targeted CL-DNA nanoparticles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Occurrence and Minimization of Cysteine Racemization during Stepwise Solid-Phase Peptide Synthesis(1)(,)(2).

    Science.gov (United States)

    Han, Yongxin; Albericio, Fernando; Barany, George

    1997-06-27

    Contrary to the conventional wisdom of the peptide synthesis field, N,S-protected derivatives of cysteine can undergo substantial levels of racemization with widely-used reagents and protocols for stepwise incorporation. A systematic study of this problem has been carried out as a function of coupling conditions and beta-thiol protecting groups, i.e., S-acetamidomethyl (Acm), S-triphenylmethyl (trityl or Trt), S-2,4,6-trimethoxybenzyl (Tmob), and S-9H-xanthen-9-yl (Xan), taking advantage of a convenient and quantitative model system assay involving HPLC resolution of H-Gly-L-Cys-Phe-NH(2) from H-Gly-D-Cys-Phe-NH(2). For example, standard protocols for couplings mediated by phosphonium and aminium salts, e.g., (benzotriazolyloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), N-[(1H-benzotriazol-1-yl)(dimethylamino)methylene]-N-methylmethanaminium hexafluorophosphate N-oxide (HBTU), N-[[(dimethylamino)-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl]methylene]-N-methylmethanaminium hexafluorophosphate N-oxide (HATU), and (7-azabenzotriazol-1-yloxy)tris(pyrrolidino)phosphonium hexafluorophosphate (PyAOP), typically involve 5-min preactivation times and are conducted in the presence of suitable additives such as 1-hydroxybenzotriazole (HOBt) or 7-aza-1-hydroxybenzotriazole (HOAt) plus a tertiary amine base such as N,N-diisopropylethylamine (DIEA) or N-methylmorpholine (NMM). Under such conditions, the levels of racemization in the model peptide, expressed as the ratio of D:L peptide formed, were in the entirely unacceptable range of 5-33%. However, these levels were in general reduced by a factor of 6- or 7-fold by avoiding the preactivation step. Additional strategies to reduce racemization involved change to a weaker base, with 2,4,6-trimethylpyridine (TMP, collidine) being substantially better than DIEA or NMM; 2-fold reduction in the amount of base; and change in solvent from neat N,N-dimethylformamide (DMF) to the less polar CH(2)Cl(2)-DMF (1:1). Coupling methods

  7. Prebiotic Peptide (Amide) Bond Synthesis Accelerated by Glycerol and Bicarbonate Under Neutral to Alkaline Dry-Down Conditions

    Science.gov (United States)

    Forsythe, J. G.; Weber, A. L.

    2017-07-01

    We report a new process for robust peptide bond synthesis in the pH 6–10 range that involves dry-down heating of amino acids in the presence of glycerol and bicarbonate (substrates: L-alanine, L-2-aminobutyric acid, β-alanine, isoserine).

  8. Synthesis and Radiolabeling of Modified Peptides Attached to Heterocyclic Rings and Their Possible Medical Applications

    International Nuclear Information System (INIS)

    Shams El-Din, H.A.A.

    2012-01-01

    Keeping in mind the pharmacological potential of heterocyclic rings as well as the advantage of biodegradability and biocompatibility of amino acids/peptides, in this thesis we were prompted for the following: 1. Synthesis of novel dipeptide derivatives coupled with different heterocyclic rings (pyridine, 1,2,4-triazol-pyridine, 1,3,4-oxadiazolpyridine and tetrazol-pyridine rings). 2. Characterization of the synthesized compounds on the basis of their spectral data (IR, Mass and 1 H-NMR spectra). 3. Study their antimicrobial activity as one of their expected biological activities. 4. Study the radioiodination of some synthesized dipeptide derivatives. 5. Study the biodistribution of the radiolabeled compounds in normal mice as preliminary studies for the possibility of using them as agents for imaging and treatment.

  9. Design, Synthesis, and Biological Evaluation of New Peptide Analogues as Selective COX-2 Inhibitors.

    Science.gov (United States)

    Ahmaditaba, Mohammad A; Shahosseini, Soraya; Daraei, Bahram; Zarghi, Afshin; Houshdar Tehrani, Mohammad H

    2017-10-01

    A new class of peptide derivatives possessing SO 2 Me and N 3 pharmacophores at the para position of a phenyl ring bound to different aromatic amino acids were synthesized based on solid-phase synthesis methodology, and evaluated as selective cyclooxygenase-2 (COX-2) inhibitors. One of the analogues, i.e., compound 2a as the representative of this series, was recognized as the highest selective COX-2 inhibitor with a COX-2 selectivity index of >500. The structure-activity relationships (SARs) acquired indicated that compound 2a containing a 4-(methylsulfonyl)benzoyl group as a pharmacophore and tyrosine as a ring bearing amino acid in the second position and glutamic acid as the C-terminal amino acid can give the essential geometry to provide selective COX-2 inhibitory activity. Antiproliferative activity of the synthesized peptides (1a-7b) was also determined against four different human cancer cell lines, including MCF-7, HepG2, A549, and HeLa. According to our results, A549, HepG2, and MCF7 seemed to be more sensitive cell lines than HeLa cells encountering these compounds, which gave inhibitory action with IC 50 values from 4.8 to 64.4 µM. In this regard, compounds 3a and 2b displayed the best inhibitory activity against the cell lines. Moreover, a good correlation was observed between the antiproliferative potency and the COX-2 inhibitory activity of compounds 1a, 2a, 2b, and 5b. Such findings suggest that one of the mechanism of anticancer activity of these peptides may be through the COX-2 inhibitory action. © 2017 Deutsche Pharmazeutische Gesellschaft.

  10. Enzymatic synthesis of tRNA-peptide conjugates and spectroscopic studies of fluorine-modified RNA

    International Nuclear Information System (INIS)

    Graber, D.

    2010-01-01

    The research presented in this thesis concerns the enzymatic synthesis of artificially modified tRNA, in particular the preparation of non-hydrolysable tRNA-peptide conjugates. Another focus is on NMR-spectroscopic investigations of fluorine-modified RNA. In both projects, chemical methods were developed to address specific RNA-biological research questions. In the first part of this thesis the preparation of tRNA-peptide conjugates with a non-hydrolysable 3'-amide linkage is presented. These molecules are of high relevance for the characterization of ribosomal processes that occur in the peptidyl transferase center (such as peptide bond formation, peptide release, or translocation) using X-ray crystallography and biochemical methods. First, a novel concept to prepare chemically modified ('labeled') tRNA was elaborated based on the combination of solid-phase synthesis and enzymatic ligation. Thereby, a variety of differently labeled tRNAs was achieved. Moreover, the most successful high-yield ligation sites were identified to be situated within the TΨ C-loop. Optimization of the synthesis and the corresponding HPLC-purification of the conjugates were initially conducted with puromycin derivatized tRNA. In the course of this project, also two tRNAs with a ribose 3'-amino group at the terminal adenosine A76 were synthesized. For that purpose a protection group pattern had to be developed to obtain a functionalized solid-support bound to 3'-amino-3'-deoxyadenosine which was appropriate for RNA solid-phase synthesis. The successful preparation of tRNA-peptide conjugates was accomplished in cooperation with Holger Moroder and Jessica Steger (Micura group) who contributed short synthetic RNA-peptide conjugates. These fragments represented the tRNA 3'-termini that were required for exploring the new ligation strategies for non-hydrolisable tRNA - a main aim of this thesis. If the 5'-fragments are synthesized by solid-phase synthesis or in vitro transcription they do not

  11. Synthesis, properties, and application in peptide chemistry of a magnetically separable and reusable biocatalyst

    Science.gov (United States)

    Liria, Cleber W.; Ungaro, Vitor A.; Fernandes, Raphaella M.; Costa, Natália J. S.; Marana, Sandro R.; Rossi, Liane M.; Machini, M. Teresa

    2014-11-01

    Enzyme-catalyzed chemical processes are selective, very productive, and generate little waste. Nevertheless, they may be optimized using enzymes bound to solid supports, which are particularly important for protease-mediated reactions since proteases undergo fast autolysis in solution. Magnetic nanoparticles are suitable supports for this purpose owing to their high specific surface area and to be easily separated from reaction media. Here we describe the immobilization of bovine α-chymotrypsin (αCT) on silica-coated superparamagnetic nanoparticles (Fe3O4@silica) and the characterization of the enzyme-nanoparticle hybrid (Fe3O4@silica-αCT) in terms of protein content, properties, recovery from reaction media, application, and reuse in enzyme-catalyzed peptide synthesis. The results revealed that (i) full acid hydrolysis of the immobilized protease followed by amino acid analysis of the hydrolyzate is a reliable method to determine immobilization yield; (ii) despite showing lower amidase activity and a lower K cat/ K m value for a specific substrate than free αCT, the immobilized enzyme is chemically and thermally more stable, magnetically recoverable from reaction media, and can be consecutively reused for ten cycles to catalyze the amide bond hydrolysis and ester hydrolysis of the protected dipeptide Z-Ala-Phe-OMe. Altogether, these properties indicate the potential of Fe3O4@silica-αCT to act as an efficient, suitably stable, and reusable catalyst in amino acid, peptide, and protein chemistry as well as in proteomic studies.

  12. Vector synthesis high-resolution electrocardiography, atrial natriuretic peptide and N-terminal prohormone brain natriuretic peptide for estimation of cardiac load in pregnancy.

    Science.gov (United States)

    Tanaka, Shino; Oyama, Rie; Fukushima, Akimune; Kikuchi, Akihiko; Sugiyama, Toru

    2016-12-01

    We analyzed atrial natriuretic peptide (ANP), N-terminal pro-brain natriuretic natriuretic peptide (NT-proBNP) and vector synthesis high-resolution electrocardiography (ECG), to estimate cardiac load with circulatory dynamic change from pregnancy through the post-partum period. The subjects were singleton pregnant women (n = 19), who were divided into three stages: stage 1, 34-36 weeks of gestation; stage 2, 2-6 post-partum days; and stage 3, 1-3 months after delivery. Vector synthesis high-resolution ECG, ANP and NT-proBNP were analyzed for all subjects. A pregnant woman with massive uterin liomyoma expressed largest the corrected recover time (RTc) dispersion in I + II of tow Dimensional (2D) color distribution map ANP and NT-proBNP were significantly higher in stage 2 than in stages 1 and 3. ANP, NT-proBNP and vector synthesis high-resolution ECG there might be able to evaluate cardiac load of normal pregnancy. © 2016 The Authors. Journal of Obstetrics and Gynaecology Research published by John Wiley & Sons Australia, Ltd on behalf of Japan Society of Obstetrics and Gynecology.

  13. Oostatic peptides containing d-amino acids: synthesis, oostatic activity, degradation, accumulation in ovaries and NMR study

    Czech Academy of Sciences Publication Activity Database

    Hlaváček, Jan; Tykva, Richard; Holík, Josef; Bennettová, Blanka; Buděšínský, Miloš; Vlasáková, Věra; Černý, Bohuslav; Slaninová, Jiřina

    2012-01-01

    Roč. 42, č. 5 (2012), s. 1715-1725 ISSN 0939-4451 R&D Projects: GA ČR GA203/06/1272 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50380511; CEZ:AV0Z50070508 Keywords : D-amino acids * oostatic peptide synthesis * H-3 labeling * oostatic activity in Neobellieria bullata * H-3 incorporation * Peptide degradation * NMR study Subject RIV: CC - Organic Chemistry Impact factor: 3.914, year: 2012

  14. Nanobiostructure of fibrous-like alumina functionalized with an analog of the BP100 peptide: Synthesis, characterization and biological applications.

    Science.gov (United States)

    Torres, L M F C; Braga, N A; Gomes, I P; Almeida, M T; Santos, T L; de Mesquita, J P; da Silva, L M; Martins, H R; Kato, K C; Dos Santos, W T P; Resende, J M; Pereira, M C; Bemquerer, M P; Rodrigues, M A; Verly, R M

    2018-03-01

    The functionalization of alumina nanoparticles of specific morphology with antimicrobial peptides (AMP) can be a promising strategy for modeling medical devices and packaging materials for cosmetics, medicines or food, since the contamination by pathogens could be reduced. In this paper, we show the synthesis of a fibrous-like alumina nanobiostructure, as well as its functionalization with the peptide EAAA-BP100, an analog of the antimicrobial peptide BP100. The antibacterial activity of the obtained material against some bacterial strains is also investigated. The covalent binding of the peptide to the nanoparticles was promoted by a reaction between the carboxyl group of the glutamate side chain (E1) of the peptide and the amino groups of the alumina nanoparticles, previously modified by reaction with 3-aminopropyltrietoxysilane (APTES). The functionalized nanoparticles were characterized by zeta potential measurements, Fourier transform infrared spectroscopy, and other physicochemical techniques. Although the obtained alumina nanobiostructure shows a relatively low degree of substitution with EAAA-BP100, antibacterial activities against Escherichia coli and Salmonella typhimurium strains are appreciably higher than the activities of the free peptide. The obtained results can affect the design of new hybrid nanobiomaterials based on nanoparticles functionalized with AMP. Copyright © 2018. Published by Elsevier B.V.

  15. Synthesis of a designed transmembrane protein by thioether ligation of solubilised segments : Nα-haloacetylated peptides survived resin cleavage using TFA with EDT as scavenger

    NARCIS (Netherlands)

    Englebretsen, D.R; Choma, C.T.; Robillard, G.T.

    1998-01-01

    Nα-haloacetylated peptides made by Fmoc solid phase synthesis survived cleavage when EDT was used as a cleavage component. Two segments of a desgned transmembrane protein, one bromoacetylated, the other containing a cysteine, and each bearing a "solubilising tail" peptide, were synthesised by Fmoc

  16. DNA Binding Peptide Directed Synthesis of Continuous DNA Nanowires for Analysis of Large DNA Molecules by Scanning Electron Microscope.

    Science.gov (United States)

    Kim, Kyung-Il; Lee, Seonghyun; Jin, Xuelin; Kim, Su Ji; Jo, Kyubong; Lee, Jung Heon

    2017-01-01

    Synthesis of smooth and continuous DNA nanowires, preserving the original structure of native DNA, and allowing its analysis by scanning electron microscope (SEM), is demonstrated. Gold nanoparticles densely assembled on the DNA backbone via thiol-tagged DNA binding peptides work as seeds for metallization of DNA. This method allows whole analysis of DNA molecules with entangled 3D features. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Human antimicrobial peptide histatin 5 is a cell-penetrating peptide targeting mitochondrial ATP synthesis in Leishmania

    NARCIS (Netherlands)

    Luque-Ortega, R.J.; van 't Hof, W.; Veerman, E.C.I.; Saugar, J.M.; Rivas, L.

    2008-01-01

    Histatin 5 (Hst5) is a human salivary antimicrobial peptide that targets fungal mitochondria. In the human parasitic protozoa Leishmania, the mitochondrial ATP production is essential, as it lacks the bioenergetic switch between glycolysis and oxidative phosphorylation described in some yeasts. On

  18. Methods, setup and safe handling for anhydrous hydrogen fluoride cleavage in Boc solid-phase peptide synthesis.

    Science.gov (United States)

    Muttenthaler, Markus; Albericio, Fernando; Dawson, Philip E

    2015-07-01

    Solid-phase peptide synthesis (SPPS) using tert-butyloxycarbonyl (Boc)/benzyl (Bzl) chemistry is an indispensable technique in many laboratories around the globe, and it provides peptides to the pharmaceutical industry and to thousands of scientists working in basic research. The Boc/Bzl strategy has several advantages, including reliability in the synthesis of long and difficult polypeptides, alternative orthogonality regarding protecting groups and ease of producing C-terminal thioesters for native chemical ligation applications. In this process, anhydrous hydrogen fluoride (HF) is used to remove the side chain protecting groups of the assembled peptide and to release the peptide from the resin, a process typically described as 'HF cleavage'. This protocol describes the general methodology, apparatus setup and safe handling of HF, with the aim of providing comprehensive information on the safe use of this valuable, well-studied and validated cleavage technique. We explain the cleavage mechanism, the physicochemical properties and risks of HF, first aid measures and the correct use of the apparatus. In addition, we provide advice on scavenger selection, as well as a troubleshooting section and video material illustrating key steps of the procedure. The protocol comprises precleavage sample preparation (30 min-2.5 h), complete HF cleavage procedure (2 h) and reaction workup (30 min).

  19. Practical protocols for stepwise solid-phase synthesis of cysteine-containing peptides.

    Science.gov (United States)

    Angell, Y M; Alsina, J; Albericio, F; Barany, G

    2002-11-01

    This study details a series of conditions that may be applied to ensure 'safe' incorporation of cysteine with minimal racemization during automated or manual solid-phase peptide synthesis. Earlier studies from our laboratories [Han et al. (1997) J. Org. Chem. 62, 4307-4312] showed that several common coupling methods, including those exploiting in situ activating agents such as N-[(dimethylamino)-1H-1,2,3-triazolo[4,5-b]pyridin-1-ylmethylene]-N-methylmethanaminium hexafluorophosphate N-oxide (HATU), N-[1H-benzotriazol-1-yl)-(dimethylamino)methylene]-N-methylmethanaminium hexafluorophosphate N-oxide (HBTU), and (benzotriazol-1-yl-N-oxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP) [all in the presence of N-methylmorpholine (NMM) or N,N-diisopropylethylamine (DIEA) as a tertiary amine base], give rise to unacceptable levels (i.e. 5-33%) of cysteine racemization. As demonstrated on the tripeptide model H-Gly-Cys-Phe-NH(2), and on the nonapeptide dihydrooxytocin, the following methods are recommended: O-pentafluorophenyl (O-Pfp) ester in DMF; O-Pfp ester/1-hydroxybenzotriazole (HOBt) in DMF; N,N'-diisopropylcarbodiimide (DIPCDI)/HOBt in DMF; HBTU/HOBt/2,4,6-trimethylpyridine (TMP) in DMF (preactivation time 3.5-7.0 min in all of these cases); and HBTU/HOBt/TMP in CH(2)Cl(2)/DMF (1:1) with no preactivation. In fact, several of the aforementioned methods are now used routinely in our laboratory during the automated synthesis of analogs of the 58-residue protein bovine pancreatic trypsin inhibitor (BPTI). In addition, several highly hindered bases such as 2,6-dimethylpyridine (lutidine), 2,3,5,6-tetramethylpyridine (TEMP), octahydroacridine (OHA), and 2,6-di-tert-butyl-4-(dimethylamino)pyridine (DB[DMAP]) may be used in place of the usual DIEA or NMM to minimize cysteine racemization even with the in situ coupling protocols.

  20. Design, Synthesis, and Biological Evaluation of Vanillin Hydroxamic Acid Derivatives as Novel Peptide Deformylase Inhibitors.

    Science.gov (United States)

    Gao, Jian; Qiu, Shengzhi; Liang, Li; Hao, Zhixiang; Zhou, Qianqian; Wang, Fanfan; Mou, Jie; Lin, Qisi

    2018-01-01

    Infectious disease is increasingly hampering human health, which challenge the discovery of new antibacterial target. Peptide deformylase (PDF), a metalloenzyme responsible for catalyzing the removal of the N-formyl group from nascent proteins, was considered as an important target in antibacterial drug discovery. Reported here are the design, synthesis and biological evaluation of vanillin hydroxamic acid derivatives. Analysis of the structure-activity relationships lead to the discovery of compound 8, which exhibits promising antibacterial activity against Escherichia coli, Staphylococcus aureus, Aspergillus oryzae, and Aspergillus foetidus with the MIC value of 0.32 µg/ml, 0.32 µg/ml, 0.16 µg/ml and 0.16 µg/ml, respectively. Furthermore, molecular docking study was applied to elucidate binding interaction between compound 8 and PDF, which indicate that compound 8 not only shares the same binding pocket with actinonin, but also has a similar binding pattern. In silico pharmacokinetic and toxicity prediction studies also suggested that compound 8 has a relatively high drug score of 0.80, and has no risk of toxicity. Compound 8 might represent a promising scaffold for the further development of novel antibacterial drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  1. Synthesis of Mono-PEGylated Growth Hormone Releasing Peptide-2 and Investigation of its Biological Activity.

    Science.gov (United States)

    Hu, Xiaoyu; Xu, Beihua; Zhou, Ziniu

    2015-10-01

    The purpose of this study was to investigate an efficient synthetic route to the mono-PEGylated growth hormone releasing peptide-2 (GHRP-2) and its biological activity in vivo. The commercially available key PEGylating reagent, mPEG-NHS ester, was successfully utilized to the synthesis of mono-PEGylated GHRP-2, during which the PEGylation profiles of GHRP-2 were monitored by high-performance liquid chromatography (HPLC). The product was purified by cation exchange chromatography, and its biological activity was conducted in rats. The desired mono-PEGylated GHRP-2 as the major product was readily obtained in anhydrous aprotic solvent, such as dimethyl formamide (DMF) and dimethylsulfoxide (DMSO), when the molar ratio of mPEG-NHS ester to GHRP-2 was fixed to be 0.8:1. The products were characterized by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. The evaluation of the biological activity for the products showed that the mono-PEGylated GHRP-2 gave a more stable activity than GHRP-2, suggesting that PEGylation led to the increase in the half-life of GHRP-2 in plasma without greatly impairing the biological activity. PEGylation of the GHRP-2 is a good choice for the development of the GHRP-2 applications.

  2. A new strategy for the preparation of peptide-targeted technetium and rhenium radiopharmaceuticals. The automated solid-phase synthesis, characterization, labeling, and screening of a peptide-ligand library targeted at the formyl peptide receptor.

    Science.gov (United States)

    Stephenson, Karin A; Banerjee, Sangeeta Ray; Sogbein, Oyebola O; Levadala, Murali K; McFarlane, Nicole; Boreham, Douglas R; Maresca, Kevin P; Babich, John W; Zubieta, Jon; Valliant, John F

    2005-01-01

    A new solid-phase synthetic methodology was developed that enables libraries of peptide-based Tc(I)/Re(I) radiopharmaceuticals to be prepared using a conventional automated peptide synthesizer. Through the use of a tridentate ligand derived from N-alpha-Fmoc-l-lysine, which we refer to as a single amino acid chelate (SAAC), a series of 12 novel bioconjugates [R-NH(CO)ZLF(SAAC)G, R = ethyl, isopropyl, n-propyl, tert-butyl, n-butyl, benzyl; Z = Met, Nle] that are designed to target the formyl peptide receptor (FPR) were prepared. Construction of the library was carried out in a multiwell format on an Advanced ChemTech 348 peptide synthesizer where multi-milligram quantities of each peptide were isolated in high purity without HPLC purification. After characterization, the library components were screened for their affinity for the FPR receptor using flow cytometry where the K(d) values were found to be in the low micromolar range (0.5-3.0 microM). Compound 5j was subsequently labeled with (99m)Tc(I) and the product isolated in high radiochemical yield using a simple Sep-Pak purification procedure. The retention time of the labeled compound matched that of the fully characterized Re-analogue which was prepared through the use of the same solid-phase synthesis methodology that was used to construct the library. The work reported here is a rare example of a method by which libraries of peptide-ligand conjugates and their rhenium complexes can be prepared.

  3. Synthesis of a Hoechst 32258 analogue amino acid building block for direct incorporation of a fluorescent, high-affinity DNA binding motif into peptides

    DEFF Research Database (Denmark)

    Behrens, C; Harrit, N; Nielsen, P E

    2001-01-01

    The synthesis of a new versatile "Hoechst 33258-like" Boc-protected amino acid building block for peptide synthesis is described. It is demonstrated that this new ligand is an effective mimic of Hoechst 33258 in terms of DNA affinity and sequence specificity. Furthermore, this minor groove binder...

  4. Butelase 1 is an Asx-specific ligase enabling peptide macrocyclization and synthesis.

    Science.gov (United States)

    Nguyen, Giang K T; Wang, Shujing; Qiu, Yibo; Hemu, Xinya; Lian, Yilong; Tam, James P

    2014-09-01

    Proteases are ubiquitous in nature, whereas naturally occurring peptide ligases, enzymes catalyzing the reverse reactions of proteases, are rare occurrences. Here we describe the discovery of butelase 1, to our knowledge the first asparagine/aspartate (Asx) peptide ligase to be reported. This highly efficient enzyme was isolated from Clitoria ternatea, a cyclic peptide-producing medicinal plant. Butelase 1 shares 71% sequence identity and the same catalytic triad with legumain proteases but does not hydrolyze the protease substrate of legumain. Instead, butelase 1 cyclizes various peptides of plant and animal origin with yields greater than 95%. With Kcat values of up to 17 s(-1) and catalytic efficiencies as high as 542,000 M(-1) s(-1), butelase 1 is the fastest peptide ligase known. Notably, butelase 1 also displays broad specificity for the N-terminal amino acids of the peptide substrate, thus providing a new tool for C terminus-specific intermolecular peptide ligations.

  5. Bridging the gap between cell biology and organic chemistry: chemical synthesis and biological application of lipidated peptides and proteins.

    Science.gov (United States)

    Peters, Carsten; Wagner, Melanie; Völkert, Martin; Waldmann, Herbert

    2002-09-01

    We have developed a basic concept for studying cell biological phenomena using an interdisciplinary approach starting from organic chemistry. Based on structural information available for a given biological phenomenon, unsolved chemical problems are identified. For their solution, new synthetic pathways and methods are developed, which reflect the state of the art in synthesising lipidated peptide conjugates. These compounds are used as molecular probes for the investigation of biological phenomena that involve both the determination of biophysical properties and cell biological studies. The interplay between organic synthesis, biophysics and cell biology in the study of protein lipidation may open up new and alternative opportunities to gain knowledge about the biological phenomenon that could not be obtained by employing biological techniques alone. This fruitful combination is highlighted using the Ras protein as an outstanding example. Included herein is: the development of methods for the synthesis of Ras-derived peptides and fully functional Ras proteins, the determination of the biophysical properties, in particular the ability to bind to model membranes, and finally the use of synthetic Ras peptides and proteins in cell biological experiments.

  6. Chemical Synthesis and In Vitro Evaluation of a Phage Display-Derived Peptide Active against Infectious Salmon Anemia Virus.

    Science.gov (United States)

    Ojeda, Nicolás; Cárdenas, Constanza; Guzmán, Fanny; Marshall, Sergio H

    2016-04-01

    pathogen has made prophylactic control extremely difficult. The identified antiviral peptide efficiently impairs ISAV infection in vitro by specifically blocking hemagglutinin-esterase, a pivotal surface protein of this virus. Peptide synthesis could further modify the primary structure of the identified peptide to improve specific activity and stability. The present results form the foundation for developing a new pharmacological treatment against ISAV. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  7. Microwave-assisted solid-phase peptide synthesis of the 60-110 domain of human pleiotrophin on 2-chlorotrityl resin.

    Science.gov (United States)

    Friligou, Irene; Papadimitriou, Evangelia; Gatos, Dimitrios; Matsoukas, John; Tselios, Theodore

    2011-05-01

    A fast and efficient microwave-assisted solid phase peptide synthesis (MW-SPPS) of a 51mer peptide, the main heparin-binding site (60-110) of human pleiotrophin (hPTN), using 2-chlorotrityl chloride resin (CLTR-Cl) following the 9-fluorenylmethyloxycarbonyl/tert-butyl (Fmoc/tBu) methodology and with the standard N,N'-diisopropylcarbodiimide/1-hydroxybenzotriazole (DIC/HOBt) coupling reagents, is described. An MW-SPPS protocol was for the first time successfully applied to the acid labile CLTR-Cl for the faster synthesis of long peptides (51mer peptide) and with an enhanced purity in comparison to conventional SPPS protocols. The synthesis of such long peptides is not trivial and it is generally achieved by recombinant techniques. The desired linear peptide was obtained in only 30 h of total processing time and in 51% crude yield, in which 60% was the purified product obtained with 99.4% purity. The synthesized peptide was purified by reversed phase high performance liquid chromatography (RP-HPLC) and identified by electrospray ionization mass spectrometry (ESI-MS). Then, the regioselective formation of the two disulfide bridges of hPTN 60-110 was successfully achieved by a two-step procedure, involving an oxidative folding step in dimethylsulfoxide (DMSO) to form the Cys(77)-Cys(109) bond, followed by iodine oxidation to form the Cys(67)-Cys(99) bond.

  8. Studies of the chemical basis of the origin of protein synthesis Initiation and direction of peptide growth

    Science.gov (United States)

    Mullins, D. W., Jr.; Lacey, J. C., Jr.

    1980-01-01

    The data presented in this paper show that the ease of nonenzymatic activation of carboxylic acids by ATP at pH 5 varies directly with the pKa of the carboxyl group, and is consistent with the idea that it is the protonated form of the carboxyl group which participates in the activation reaction. Consequently, since most N-blocked amino acids have higher pKas than do their unblocked forms, they are activated more readily, and it has been demonstrated that this principle applies to peptides as well, which are activated more rapidly than single amino acids. It is proposed that this fact may be partly responsible for the origin of two important features still observed in contemporary protein synthesis: (1) initiation in prokaryotes is accomplished with an N-blocked amino acid, and (2) elongation in all living systems occurs at the carboxyl end of the growing peptide.

  9. Optimization of synthesis and quality control procedures for the preparations of 18F and 123I labelled peptides

    International Nuclear Information System (INIS)

    Archimandritis, S.C.; Potamianos, S.; Varvarigou, A.D.

    2002-01-01

    Radiolabelled biomolecules like proteins and peptides, are playing now days an important role in experimental and clinical Nuclear Medicine. Radioiodination techniques remain important, with improvements accounting for high purity, specific activity and better in vivo stability. Radioiodination using prosthetic groups is the method of choice in cases where the molecules are lacking of thyrosyl groups in their structure and are also sensitive to circulating dehalogenase enzymes. This investigation was based on the need to optimize labelling and quality control techniques for these molecules. The N-succinimidyliodobenzoate (SIB) was used in this study as the prosthetic group for the radioiodination. Optimization of SIB synthesis and modification of the protocol resulted in an improved mean yield of SIB. The combination of TLC and column chromatography using silica gel proved suitable in identifying SIB. Furthermore, the ability of SIB to couple to protein was also used to confirm the presence of SIB. In this case, SEC and ITLC-SG proved suitable to confirm protein binding of SIB. Column chromatography using silica gel containing Sep-Pak was appropriate for SIB purification. Concerning SIB conjugation to peptides, high radioiodination yields were only possible for peptides with amino-containing-side-chain amino acids. Furthermore, lysine containing peptides retained stability, at 4 deg. C, for at least 24 h and reverse phase HPLC proved the most suitable technique for assessing conjugation of SIB to peptide. The biological evaluation of the radiolabelled product was made in normal mice. SIB and SIB-peptide conjugates were tested comparatively and a number of tentative but interesting inferences were drawn. SIB and its peptide conjugates exhibited good in vivo stability as evidenced by low thyroid accumulation and were cleared via the kidneys. A time dependant decrease in the% dose per gram of tissue indicates possible adrenal metabolism of SIB and SIB-peptide

  10. Aryldithioethyloxycarbonyl (Ardec): a new family of amine protecting groups removable under mild reducing conditions and their applications to peptide synthesis.

    Science.gov (United States)

    Lapeyre, Milaine; Leprince, Jérôme; Massonneau, Marc; Oulyadi, Hassan; Renard, Pierre-Yves; Romieu, Anthony; Turcatti, Gerardo; Vaudry, Hubert

    2006-04-24

    The development of phenyldithioethyloxycarbonyl (Phdec) and 2-pyridyldithioethyloxycarbonyl (Pydec) protecting groups, which are thiol-labile urethanes, is described. These new disulfide-based protecting groups were introduced onto the epsilon-amino group of L-lysine; the resulting amino acid derivatives were easily converted into N alpha-Fmoc building blocks suitable for both solid- and solution-phase peptide synthesis. Model dipeptide(Ardec)s were prepared by using classical peptide couplings followed by standard deprotection protocols. They were used to optimize the conditions for complete thiolytic removal of the Ardec groups both in aqueous and organic media. Phdec and Pydec were found to be cleaved within 15 to 30 min under mild reducing conditions: i) by treatment with dithiothreitol or beta-mercaptoethanol in Tris.HCl buffer (pH 8.5-9.0) for deprotection in water and ii) by treatment with beta-mercaptoethanol and 1,8-diazobicyclo[5.4.0]undec-7-ene (DBU) in N-methylpyrrolidinone for deprotection in an organic medium. Successful solid-phase synthesis of hexapeptides Ac-Lys-Asp-Glu-Val-Asp-Lys(Ardec)-NH2 has clearly demonstrated the full orthogonality of these new amino protecting groups with Fmoc and Boc protections. The utility of the Ardec orthogonal deprotection strategy for site-specific chemical modification of peptides bearing several amino groups was illustrated firstly by the preparation of a fluorogenic substrate for caspase-3 protease containing the cyanine dyes Cy 3.0 and Cy 5.0 as FRET donor/acceptor pair, and by solid-phase synthesis of an hexapeptide bearing a single biotin reporter group.

  11. Synthesis of Bioinorganic Antimicrobial Peptide Nanoparticles with Potential Therapeutic Properties (POSTPRINT)

    Science.gov (United States)

    2008-07-01

    synthetic phospholipid vesicles, and polymer sponges ).23–26 Enzyme encapsulation techniques mimic the processes carried out by organisms that...Originally isolated from a combinatorial peptide array, KSL demonstrates activity against a wide range of microorganisms .10,48 KSL (4 2488...the peptide from other factors that could otherwise limit its activity. For example, Staphylococcus sp. and other microorganisms release degrada

  12. Chemo-enzymatic peptide synthesis and derivatisation using Subtilisin A in anhydrous organic solvents

    NARCIS (Netherlands)

    Nuijens, T.

    2012-01-01

    In this thesis it is demonstrated that Alcalase and Cal-B in neat organic solvent can perform unique and cost-efficient conversions that are useful in the peptide area. Not only can Alcalase be used to prepare several C-terminally derivatized amino acids and peptides (such as amides, esters and

  13. Synthesis and antiviral activity of PB1 component of the influenza A RNA polymerase peptide fragments.

    Science.gov (United States)

    Matusevich, O V; Egorov, V V; Gluzdikov, I A; Titov, M I; Zarubaev, V V; Shtro, A A; Slita, A V; Dukov, M I; Shurygina, A-P S; Smirnova, T D; Kudryavtsev, I V; Vasin, A V; Kiselev, O I

    2015-01-01

    This study is devoted to the antiviral activity of peptide fragments from the PB1 protein - a component of the influenza A RNA polymerase. The antiviral activity of the peptides synthesized was studied in MDCK cell cultures against the pandemic influenza strain A/California/07/2009 (H1N1) pdm09. We found that peptide fragments 6-13, 6-14, 26-30, 395-400, and 531-540 of the PB1 protein were capable of suppressing viral replication in cell culture. Terminal modifications i.e. N-acetylation and C-amidation increased the antiviral properties of the peptides significantly. Peptide PB1 (6-14) with both termini modified showed maximum antiviral activity, its inhibitory activity manifesting itself during the early stages of viral replication. It was also shown that the fluorescent-labeled analog of this peptide was able to penetrate into the cell. The broad range of virus-inhibiting activity of PB1 (6-14) peptide was confirmed using a panel of influenza A viruses of H1, H3 and H5 subtypes including those resistant to oseltamivir, the leading drug in anti-influenza therapy. Thus, short peptide fragments of the PB1 protein could serve as leads for future development of influenza prevention and/or treatment agents. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Synthesis, analysis, and cytotoxic effects of novel SMAC-based peptides

    Czech Academy of Sciences Publication Activity Database

    Georgieva, M.; Dzimbova, T.; Sázelová, Petra; Detcheva, R.; Kašička, Václav; Momekov, G.; Pajpanova, T.

    2015-01-01

    Roč. 47, č. 8 (2015), s. 1687 ISSN 0939-4451. [International Congress on Amino Acids, Peptides and Proteins /14./. 03.08.2015-07.08.2015, Vienna] Institutional support: RVO:61388963 Keywords : apoptotic peptides * SMAC-mimetics * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation

  15. Solid-phase peptide synthesis of endothelin receptor antagonists on novel flexible, styrene-acryloyloxyhydroxypropyl methacrylate-tripropyleneglycol diacrylate [SAT] resin.

    Science.gov (United States)

    Siyad, M A; Nair, Arun S V; Kumar, G S Vinod

    2010-03-08

    Novel cross-linked polymeric support by the copolymerization of styrene and 3-(acryloyloxy)-2-hydroxypropyl methacrylate with Tri(propyleneglycol) diacryalte (SAT) for solid-phase peptide synthesis is presented here. The synthesis of SAT is based on the cross-linking of 3-(acryloyloxy)-2-hydroxypropyl methacrylate with styrene by free-radical suspension polymerization, consisting of an ester and a secondary hydroxyl group. An additional cross-linker tri(propyleneglycol) diacryalte provides a hydrophilic environment throughout the resin, which will enhance the physicochemical properties of the resin toward organic synthesis. The resins were synthesized in various cross-linking densities to check the swelling property, mechanical stability, and functional loading capacity. The resin was characterized by the IR, (13)C NMR, and SEM techniques. The extent of swelling properties of the polymer of different cross-linking densities were studied and compared with Merrifield resin and TentaGel. To demonstrate the efficiency of SAT support was proved by synthesizing the challenging peptide sequence of acyl carrier protein (ACP) and compared with commercially available Merrifield resin. It was further tested by synthesizing endothelial receptor antagonist peptides using SAT resin and compared with commercially available TentaGel resin. The standard Fmoc strategy was adopted for peptide synthesis and was characterized by MALDI-TOF MS and analyzed the purity of peptides by HPLC.

  16. Synthesis, molecular docking, antimicrobial, antioxidant and toxicity assessment of quinoline peptides.

    Science.gov (United States)

    Thangaraj, Muthu; Gengan, Robert Moonsamy; Ranjan, Bibhuti; Muthusamy, Ramesh

    2018-01-01

    A series of quinoline based peptides were synthesized by a one-pot reaction through Ugi-four component condensation of lipoic acid, cyclohexyl isocyanide, aniline derivatives and 2-methoxy quinoline-3-carbaldehyde derivatives under microwave irradiation. The products were obtained in excellent yields and high purity. Solvent optimization and the effect of microwave irradiation with various powers were also observed. All the synthesized compounds were characterized by FTIR, NMR spectral data and elemental analysis. A total of eight peptides were subjected to antimicrobial, antioxidant and toxicity evaluation. Among them, four peptides showed potential towards antibacterial screening with Bacillus cereus, Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Candida albicans, Candida utilis and three peptides showed antioxidant test positive (DPPH). Besides, toxicity of all the peptides were evaluated by using brine shrimp and it was observed that four peptides showed mortality rate less than 50% up to 48h. Molecular docking studies revealed that the higher binding affinity of the two peptides toward DNA gyrase than ciprofloxacin based on Libdock score. The described chemistry represents a facile tool to synthesize complex heterocycles of pharmaceutical relevance in a highly efficient and one-pot fashion. The advantages of this method are its green approach, inexpensive solvent, shorter reaction times and excellent yields. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Novel Synthesis of Core-Shell Silica Nanoparticles for the Capture of Low Molecular Weight Proteins and Peptides

    Directory of Open Access Journals (Sweden)

    Sergio G. Hernandez-Leon

    2017-10-01

    Full Text Available Silica nanoparticles were functionalized with immobilized molecular bait, Cibacron Blue, and a porous polymeric bis-acrylamide shell. These nanoparticles represent a new alternative to capture low molecular weight (LMW proteins/peptides, that might be potential biomarkers. Functionalized core-shell silica nanoparticles (FCSNP presented a size distribution of 243.9 ± 11.6 nm and an estimated surface charge of −38.1 ± 0.9 mV. The successful attachment of compounds at every stage of synthesis was evidenced by ATR-FTIR. The capture of model peptides was determined by mass spectrometry, indicating that only the peptide with a long sequence of hydrophobic amino acids (alpha zein 34-mer interacted with the molecular bait. FCSNP excluded the high molecular weight protein (HMW, BSA, and captured LMW proteins (myoglobin and aprotinin, as evidenced by SDS-PAGE. Functionalization of nanoparticles with Cibacron Blue was crucial to capture these molecules. FCSNP were stable after twelve months of storage and maintained a capacity of 3.1–3.4 µg/mg.

  18. Synthesis and in vitro evaluation of PNA-peptide-DETA conjugates as potential cell penetrating artificial ribonucleases.

    Science.gov (United States)

    Petersen, Lene; de Koning, Martijn C; van Kuik-Romeijn, Petra; Weterings, Jimmy; Pol, Christine J; Platenburg, Gerard; Overhand, Mark; van der Marel, Gijsbert A; van Boom, Jacques H

    2004-01-01

    We report the synthesis of novel artificial ribonucleases with potentially improved cellular uptake. The design of trifunctional conjugates 1a and 1b is based on the specific RNA-recognizing properties of PNA, the RNA-cleaving abilities of diethylenetriamine (DETA), and the peptide (KFF)(3)K for potential uptake into E. coli. The conjugates were assembled in a convergent synthetic route involving native chemical ligation of a PNA, containing an N-terminal cysteine, with the C-terminal thioester of the cell-penetrating (KFF)(3)K peptide to give 12a and 12b. These hybrids contained a free cysteine side-chain, which was further functionalized with an RNA-hydrolyzing diethylenetriamine (DETA) moiety. The trifunctional conjugates (1a, 1b) were evaluated for RNA-cleaving properties in vitro and showed efficient degradation of the target RNA at two major cleavage sites. It was also established that the cleavage efficiency strongly depended on the type of spacer connecting the PNA and the peptide.

  19. Synthesis of protected 2-pyrrolylalanine for peptide chemistry and examination of its influence on prolyl amide isomer equilibrium.

    Science.gov (United States)

    Dörr, Aurélie A; Lubell, William D

    2012-08-03

    Protected enantiopure 2-pyrrolylalanine was synthesized for application in peptide science as an electron-rich arylalanine (histidine) analog with π-donor capability. (2S)-N-(Boc)-N'-(Phenylsulfonyl)-, (2S)-N,N'-bis-(phenylsulfonyl)-, and (2S)-N,N'-bis-(Boc)-3-(2-pyrrolyl)alanines (10, 3, and 14, respectively) were made in 13-17% overall yields and six to seven steps from oxazolidine β-methyl ester 4. Homoallylic ketone 5 was prepared by a copper-catalyzed cascade addition of vinylmagnesium bromide to ester 4 and converted to pyrrolyl amino alcohol 7 by olefin oxidation and Paal-Knorr condensation. Protecting group shuffle and oxidation of the primary alcohol enabled the synthesis of pyrrolylalanines. The bis-Boc analog 14 proved useful in peptide chemistry and was employed to make N-acetyl-pyrrolylalaninyl-proline N''-methylamide 25. A study of the influence of the pyrrole moiety on the prolyl amide isomer equilibrium of 25 using (1)H NMR spectroscopy in chloroform, DMSO, and water demonstrated that the pyrrolylalanine peptide exhibited behavior and conformations different from those of other arylalanine analogs.

  20. Synthesis of Bifunctional Azobenzene Glycoconjugates for Cysteine-Based Photosensitive Cross-Linking with Bioactive Peptides.

    Science.gov (United States)

    Müller, Anne; Kobarg, Hauke; Chandrasekaran, Vijayanand; Gronow, Joana; Sönnichsen, Frank D; Lindhorst, Thisbe K

    2015-09-21

    Azobenzene linker molecules can be utilized to control peptide/protein function when they are ligated to appropriately spaced amino acid side chains of the peptide. This is because the photochemical E/Z isomerization of the azobenzene N=N double bond allows to switch peptide conformation between folded and unfolded. In this context, we have introduced carbohydrate-functionalized azobenzene derivatives in order to advance the biocompatible properties of azobenzene peptide linkers. Chloroacetamide-functionalized and O-allylated carbohydrate derivatives were synthesized and conjugated with azobenzene to achieve new bifunctional cross-linkers, in order to allow ligation to cysteine side chains by nucleophilic substitution or thiol-ene reaction, respectively. The photochromic properties of the new linker glycoconjugates were determined and first ligation reactions performed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Identification of the non-ribosomal peptide synthetase responsible for biosynthesis of the potential anti-cancer drug sansalvamide in Fusarium solani

    DEFF Research Database (Denmark)

    Romans-Fuertes, Patricia; Sondergaard, Teis Esben; Sandmann, Manuela Ilse Helga

    2016-01-01

    for sansalvamide. Sansalvamide is structurally related to the cyclic hexadepsipeptide destruxin, which both contain an α-hydroxyisocaproic acid (HICA) unit. A gene cluster responsible for destruxin production has previously been identified in Metarhizium robertsii together with a hypothetical biosynthetic pathway....... Using comparative bioinformatic analyses of the catalytic domains in the destruxin and sansalvamide NRPSs, we were able to propose a model for sansalvamide biosynthesis. Orthologues of the gene clusters were also identified in species from several other genera including Acremonium chrysogenum...

  2. Facile synthesis of aliphatic isothiocyanates and thioureas on solid phase using peptide coupling reagents

    DEFF Research Database (Denmark)

    Boas, Ulrik; Andersen, Heidi Gertz; Christensen, Jørn B.

    2004-01-01

    Peptide coupling reagents can be used as versatile reagents for the formation of aliphatic isothiocyanates and thioureas on solid phase from the corresponding solid-phase anchored aliphatic primary amines. The formation of the thioureas is fast and highly chemoselective, and proceeds via formatio...... of the intermediate isothiocyanate. The isothiocyanate and subsequent thiourea formation take place under standard peptide coupling conditions using carbon disulfide as the 'amino acid'. The thioureas are released from the resin and isolated in moderate to high yields....

  3. Peptide synthesis of gold nanoparticles: the early steps of gold reduction investigated by density functional theory.

    Science.gov (United States)

    Toroz, Dimitrios; Corni, Stefano

    2011-03-09

    Gold nanoparticles can be synthesized by reducing chloroaurate(III) ions in the presence of peptides. Here, such reduction for serine and tyrosine is studied by density functional theory including solvent effects. We find that the formation of chloroaurate complexes of these amino acids is thermodynamically viable and facilitates the reduction of Au(III), to a greater degree for tyrosine as found in experiments. Our results also suggest a rationale for the behavior of tyrosine-intercalated peptides.

  4. Facile synthesis of magnetic mesoporous hollow carbon microspheres for rapid capture of low-concentration peptides.

    Science.gov (United States)

    Cheng, Gong; Zhou, Ming-Da; Zheng, Si-Yang

    2014-08-13

    Mesoporous and hollow carbon microspheres embedded with magnetic nanoparticles (denoted as MHM) were prepared via a facile self-sacrificial method for rapid capture of low-abundant peptides from complex biological samples. The morphology, structure, surface property, and magnetism were well-characterized. The hollow magnetic carbon microspheres have a saturation magnetization value of 130.2 emu g(-1) at room temperature and a Brunauer-Emmett-Teller specific surface area of 48.8 m(2) g(-1) with an average pore size of 9.2 nm for the mesoporous carbon shell. The effectiveness of these MHM affinity microspheres for capture of low-concentration peptides was evaluated by standard peptides, complex protein digests, and real biological samples. These multifunctional hollow carbon microspheres can realize rapid capture and convenient separation of low-concentration peptides. They were validated to have better performance than magnetic mesoporous silica and commercial peptide-enrichment products. In addition, they can be easily recycled and present excellent reusability. Therefore, it is expected that this work may provide a promising tool for high-throughput discovery of peptide biomarkers from biological samples for disease diagnosis and other biomedical applications.

  5. Solid-Phase Synthesis of Difficult Purine-Rich PNAs through Selective Hmb Incorporation: Application to the Total Synthesis of Cell Penetrating Peptide-PNAs

    Directory of Open Access Journals (Sweden)

    Julien Tailhades

    2017-10-01

    Full Text Available Antisense oligonucleotide (ASO-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino and Spinraza (2′-O-methoxyethyl-phosphorothioate in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders. However, the chemical synthesis of long PNAs, which are more target-specific, remains an ongoing challenge. Most of the reported methodology for the solid-phase synthesis of PNA suffer from poor coupling efficiency which limits production to short PNA sequences of less than 15 residues. Here, we have studied the effect of backbone modifications with Hmb (2-hydroxy-4-methoxybenzyl and Dmb (2,4-dimethoxybenzyl to ameliorate difficult couplings and reduce “on-resin” aggregation. We firstly synthesized a library of PNA dimers incorporating either Hmb or Dmb and identified that Hmb is superior to Dmb in terms of its ease of removal. Subsequently, we used Hmb backbone modification to synthesize a 22-mer purine-rich PNA, targeting dystrophin RNA splicing, which could not be synthesized by standard coupling methodology. Hmb backbone modification allowed this difficult PNA to be synthesized as well as to be continued to include a cell-penetrating peptide on the same solid support. This approach provides a novel and straightforward strategy for facile solid-phase synthesis of difficult purine-rich PNA sequences.

  6. Development of a poly(dimethylacrylamide) based matrix material for solid phase high density peptide array synthesis employing a laser based material transfer

    Energy Technology Data Exchange (ETDEWEB)

    Ridder, Barbara [Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany); Foertsch, Tobias C. [Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Welle, Alexander [Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Mattes, Daniela S. [Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany); Bojnicic-Kninski, Clemens M. von; Loeffler, Felix F.; Nesterov-Mueller, Alexander [Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Meier, Michael A.R., E-mail: m.a.r.meier@kit.edu [Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany); Breitling, Frank, E-mail: frank.breitling@kit.edu [Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2016-12-15

    Highlights: • New matrix material for peptide array synthesis from a ‘solid solvent’. • Resolution was increased with possible spot densities of up to 20.000 spots per cm{sup 2}. • The coupling depth and the effectiveness of washing steps analyzed by ToF-SIMS. • Adaptations and custom changes of the matrix material are possible. - Abstract: Poly(dimethylacrylamide) (PDMA) based matrix materials were developed for laser-based in situ solid phase peptide synthesis to produce high density arrays. In this specific array synthesis approach, amino acid derivatives are embedded into a matrix material, serving as a “solid” solvent material at room temperature. Then, a laser pulse transfers this mixture to the target position on a synthesis slide, where the peptide array is synthesized. Upon heating above the glass transition temperature of the matrix material, it softens, allowing diffusion of the amino acid derivatives to the synthesis surface and serving as a solvent for peptide bond formation. Here, we synthesized PDMA six-arm star polymers, offering the desired matrix material properties, using atom transfer radical polymerization. With the synthesized polymers as matrix material, we structured and synthesized arrays with combinatorial laser transfer. With densities of up to 20,000 peptide spots per cm{sup 2}, the resolution could be increased compared to the commercially available standard matrix material. Time-of-Flight Secondary Ion Mass Spectrometry experiments revealed the penetration behavior of an amino acid derivative into the prepared acceptor synthesis surface and the effectiveness of the washing protocols.

  7. Synthesis of new bivalent peptides for applications in the Affinity Enhancement System.

    Science.gov (United States)

    Morandeau, L; Benoist, E; Loussouarn, A; Ouadi, A; Lesaec, P; Mougin, M; Faivre-Chauvet, A; Le Boterff, J; Chatal, J F; Barbet, J; Gestin, J F

    2005-01-01

    The feasibility of two-step radioimmunotherapy (RIT) of cancer by the Affinity Enhancement System (AES) has been demonstrated in experimental and clinical studies. This technique, associating a bispecific antibody and a bivalent peptide radiolabeled with iodine-131, has been developed to reduce toxicity and to improve therapeutic efficacy compared to one-step targeting methods. The use of AES with different beta-emitters such as rhenium-188, samarium-153, or lutetium-177 or alpha-emitters such as actinium-225 or bismuth-213 is now considered. Thus three new peptides, designed to allow for the coupling of a variety of bifunctional chelating agents BCA, were synthesized by associating two glycyl-succinyl-histamine (GSH) arms, which are recognized by the 679 monoclonal antibody (mAb-679), with different binding agents, such as p-nitrophenylalanine or N,N-bis(carboxymethyl)-4-N'-(9-fluorenylmethyloxycarbonyl)aminobenzylamine. Immunoreactivity and serum stability evaluation were performed for each synthesized peptide. One of the three peptides (LM218) proved to be more stable than the others, and three different BCAs were coupled to LM218 (CITC-DTPA, CITC-TTHA, and CITC-CHXA''DTPA). One of these products, LM218-BzTTHA was radiolabeled with indium-111 without loss of immunoreactivity toward the mAb-679. These new peptides will allow pretargeted RIT with a large variety of radionuclides, to adapt the choice of the radionuclide (LET, half-life, penetrating emission) to the nature and size of targeted tumors.

  8. Synthesis, Characterization and Biological Studies of 99mTc and 188Re Peptides

    Science.gov (United States)

    Sanders, Vanessa

    have the possible application to simplify the synthesis of the pharmaceutical. The versatility of the oxidation states of these metals leads to numerous possibilities in developing new radiopharmaceuticals. The coordination chemistry and reaction mechanisms must be efficiently characterized to ensure the reproducibility of the radiopharmaceutical. The current study focuses on technetium and rhenium complexes with peptides. These complexes have become increasing interesting for their use in diagnostic and therapeutic radiopharmaceuticals. The characterization of the complexation of Tc(V), and Rh(V) with the pentapeptide KYCAR (lysyl-tyrosyl-cystyl-alanyl-arginine) will be discussed. Complexes will be characterized by High Performance Liquid Chromatography (HPLC), UV-Visible Spectroscopy, Proton NMR, Circular Dichroism (CD), and Electrospray Ionization Mass Spectroscopy, to compare them to current radiopharmaceuticals. Information on the underlying reactions and coordination will be discussed.

  9. AP-1/KIF13A Blocking Peptides Impair Melanosome Maturation and Melanin Synthesis.

    Science.gov (United States)

    Campagne, Cécile; Ripoll, Léa; Gilles-Marsens, Floriane; Raposo, Graça; Delevoye, Cédric

    2018-02-14

    Melanocytes are specialized cells that generate unique organelles called melanosomes in which melanin is synthesized and stored. Melanosome biogenesis and melanocyte pigmentation require the transport and delivery of melanin synthesizing enzymes, such as tyrosinase and related proteins (e.g., TYRP1), from endosomes to maturing melanosomes. Among the proteins controlling endosome-melanosome transport, AP-1 together with KIF13A coordinates the endosomal sorting and trafficking of TYRP1 to melanosomes. We identify here β1-adaptin AP-1 subunit-derived peptides of 5 amino acids that block the interaction of KIF13A with AP-1 in cells. Incubating these peptides with human MNT-1 cells or 3D-reconstructed pigmented epidermis decreases pigmentation by impacting the maturation of melanosomes in fully pigmented organelles. This study highlights that peptides targeting the intracellular trafficking of melanocytes are candidate molecules to tune pigmentation in health and disease.

  10. AP-1/KIF13A Blocking Peptides Impair Melanosome Maturation and Melanin Synthesis

    Directory of Open Access Journals (Sweden)

    Cécile Campagne

    2018-02-01

    Full Text Available Melanocytes are specialized cells that generate unique organelles called melanosomes in which melanin is synthesized and stored. Melanosome biogenesis and melanocyte pigmentation require the transport and delivery of melanin synthesizing enzymes, such as tyrosinase and related proteins (e.g., TYRP1, from endosomes to maturing melanosomes. Among the proteins controlling endosome-melanosome transport, AP-1 together with KIF13A coordinates the endosomal sorting and trafficking of TYRP1 to melanosomes. We identify here β1-adaptin AP-1 subunit-derived peptides of 5 amino acids that block the interaction of KIF13A with AP-1 in cells. Incubating these peptides with human MNT-1 cells or 3D-reconstructed pigmented epidermis decreases pigmentation by impacting the maturation of melanosomes in fully pigmented organelles. This study highlights that peptides targeting the intracellular trafficking of melanocytes are candidate molecules to tune pigmentation in health and disease.

  11. Synthesis and SAR Study of Novel Peptide Aldehydes as Inhibitors of 20S Proteasome

    Directory of Open Access Journals (Sweden)

    Lihe Zhang

    2011-09-01

    Full Text Available Based on the analysis of the crystal structure of MG101 (1 and 20S proteasomes, a new series of peptide aldehyde derivatives were designed and synthesized. Their ability to inhibit 20S proteasome was assayed. Among them, Cbz-Glu(OtBu-Phe-Leucinal (3c, Cbz-Glu(OtBu-Leu-Leucinal (3d, and Boc-Ser(OBzl-Leu-Leucinal (3o exhibited the most activity, which represented an order of magnitude enhancement compared with MG132 (2. The covalent docking protocol was used to explore the binding mode. The structure-activity relationship of the peptide aldehyde inhibitors is discussed.

  12. P134-M Solid Phase Synthesis of C-Terminus Fluorescent Peptide: Comparison of Fmoc-Lys(5-FAM)-Resin and Fmoc-Lys[5-FAM(Trt)]-Resin

    Science.gov (United States)

    Tong, X.; Fu, W.; Sheng, L.

    2007-01-01

    Many FRET (Fluorescent Resonance Energy Transfer) peptides require a C-terminus fluorescent label. In order to facilitate the synthesis of C-terminus fluorescent peptides, we prepared and compared two kinds of resins, Fmoc-Lys(5-FAM)-resin (I) and Fmoc-Lys[5-FAM(trt)]-resin (II).1 Resin (II) has a phenolic hydroxyl group protected with trityl group. The reason for introducing the protecting group was supposedly to prevent the phenolic hydroxyl groups from reacting with the activated amino acids during peptide synthesis. In this report, a fluorescent peptide [EREQTVDLS-VKRPRTGRKKRRQ-RRRK(5-FAM)-NH2] was synthesized using each of these resins. Syntheses were carried out under similar standard conditions. The peptides obtained showed no significant difference in purity. These results showed that resin (I) is also suitable for synthesis of C-terminus fluorescent peptide.

  13. Peptide Based Targeted Therapeutic Radiopharmaceuticals: A Focus on the Synthesis of Radiolabelled Nanobodies

    International Nuclear Information System (INIS)

    Impens, N.; Campsteyn, A.; Aerts, A.; Baatout, S.; Devoogdt, N.; Caveliers, V.; Xavier, C.; Lahoutte, T.

    2009-01-01

    In 1993, the Vrije Universiteit Brussel (Brussels, Belgium) discovered in the blood of camelidae antibodies consisting of only a heavy chain. Due to the lack of the light chain only the variable part of the heavy chain is important for antigen binding. This variable part of these heavy-chain-only antibodies is a good candidate as a targeted therapeutic radiopharmaceutical and was called a nanobody, having a molecular weight of about 15 kDa. Its dimensions are included in between the small peptides like derived from e.g. somatostatin, and the classical monoclonal antibodies. This makes that some characteristics like the physical behaviour, the chemical stability, the penetration in tumour and in healthy tissues, and the blood clearance lie in between the characteristics of the small peptides and the monoclonal antibodies, therefore taking advantage of both extremes. Nanobodies have been humanised to decrease the immunogenic response. The building blocks of molecules such as the octreotide, nanobodies and monoclonal antibodies are amino acids linked via peptide bonds. The modification reactions are therefore all based on the same 'peptide chemistry'. The functional groups on the present amino acids will determine the possible reactions. In order to link a radionuclide to the nanobodies, we opted to use bifunctional ligands containing DOTA, because this is a suitable chelating agent for the diagnostic radionuclide Ga-68, and for therapeutic radionuclides such as Lu-177 and Y-90, covering short and long range β-particle emitters suitable for attacking a wide range of tumour sizes. The ratio of bifunctional ligand to nanobody can be varied by carefully selecting the functional groups of the peptide involved in the reaction with the bifunctional ligand, avoiding the complementarity determining region (CDR), i.e. the part of the molecule binding to the antigen. This is a first way to predetermine the amount of radionuclides that can be linked to the peptide, or the

  14. Synthesis of fluorescent analogues of relaxin family peptides and their preliminary in vitro and in vivo characterization

    Science.gov (United States)

    Chan, Linda; Smith, Craig; Chua, Berenice; Lin, Feng; Bathgate, Ross; Separovic, Frances; Gundlach, Andrew; Hossain, M. Akhter; Wade, John

    2013-12-01

    Relaxin, a heterodimeric polypeptide hormone, is a key regulator of collagen metabolism and multiple vascular control pathways in humans and rodents. Its actions are mediated via its cognate G-protein-coupled receptor, RXFP1 although it also ‘pharmacologically’ activates RXFP2, the receptor for the related, insulin-like peptide 3 (INSL3), which has specific actions on reproduction and bone metabolism. Therefore, experimental tools to facilitate insights into the distinct biological actions of relaxin and INSL3 are required, particularly for studies of tissues containing both RXFP1 and RXFP2. Here, we chemically functionalized human (H2) relaxin, the RXFP1-selective relaxin analogue H2:A(4-24)(F23A), and INSL3 to accommodate a fluorophore without marked reduction in binding or activation propensity. Chemical synthesis of the two chains for each peptide was followed by sequential regioselective formation of their three disulfide bonds. Click chemistry conjugation of Cy5.5 at the B-chain N-terminus, with conservation of the disulfide bonds, yielded the analogues displaying appropriate selective binding affinity and ability to activate RXFP1 and/or RXFP2 in vitro. The in vivo biological activity of Cy5.5-H2 relaxin and Cy5.5-H2:A(4-24)(F23A) was confirmed in mice, as acute icv infusion of these peptides (but not Cy5.5-INSL3) stimulated water drinking, an established behavioral response elicited by central RXFP1 activation. The central distribution of Cy5.5-conjugated peptides was examined in mice killed 30 min after infusion, revealing fluorescence within brain tissue near-adjacent to the cerebral ventricle walls relative to deeper brain areas. These data will aid the interpretation of behavioral studies. Production of fluorophore-conjugated relaxin family peptides will facilitate future pharmacological studies to probe the function of H2 relaxin/RXFP1 and INSL3/RXFP2 signaling in vivo while tracking their distribution following central or peripheral administration.

  15. Type I Collagen Synthesis Marker Procollagen I N-Terminal Peptide (PINP) in Prostate Cancer Patients Undergoing Intermittent Androgen Suppression

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Gerhard, E-mail: gerhard.hamilton@toc.lbg.ac.at; Olszewski-Hamilton, Ulrike [Ludwig Boltzmann Cluster of Translational of Oncology, Nussdorfer Strasse 64, Vienna A-1090 (Austria); Theyer, Gerhard [Hospital Kittsee, Kittsee A-2421, Burgenland (Austria)

    2011-09-15

    Intermittent androgen suppression (IAS) therapy for prostate cancer patients attempts to maintain the hormone dependence of the tumor cells by cycles alternating between androgen suppression (AS) and treatment cessation till a certain prostate-specific antigen (PSA) threshold is reached. Side effects are expected to be reduced, compared to standard continuous androgen suppression (CAS) therapy. The present study examined the effect of IAS on bone metabolism by determinations of serum procollagen I N-terminal peptide (PINP), a biochemical marker of collagen synthesis. A total of 105 treatment cycles of 58 patients with prostate cancer stages ≥pT2 was studied assessing testosterone, PSA and PINP levels at monthly intervals. During phases of AS lasting for up to nine months PSA levels were reversibly reduced, indicating apoptotic regression of the prostatic tumors. Within the first cycle PINP increased at the end of the AS period and peaked in the treatment cessation phase. During the following two cycles a similar pattern was observed for PINP, except a break in collagen synthesis as indicated by low PINP levels in the first months off treatment. Therefore, measurements of the serum PINP concentration indicated increased bone matrix synthesis in response to >6 months of AS, which uninterruptedly continued into the first treatment cessation phase, with a break into each of the following two pauses. In summary, synthesis of bone matrix collagen increases while degradation decreases during off-treatment phases in patients undergoing IAS. Although a direct relationship between bone matrix turnover and risk of fractures is difficult to establish, IAS for treatment of biochemical progression of prostate tumors is expected to reduce osteoporosis in elderly men often at high risk for bone fractures representing a highly suitable patient population for this kind of therapy.

  16. Stereoselective synthesis of macrocyclic peptides via a dual olefin metathesis and ethenolysis approach.

    Science.gov (United States)

    Mangold, Shane L; Grubbs, Robert H

    2015-08-01

    Macrocyclic compounds occupy an important chemical space between small molecules and biologics and are prevalent in many natural products and pharmaceuticals. The growing interest in macrocycles has been fueled, in part, by the design of novel synthetic methods to these compounds. One appealing strategy is ring-closing metathesis (RCM) that seeks to construct macrocycles from acyclic diene precursors using defined transition-metal alkylidene catalysts. Despite its broad utility, RCM generally gives rise to a mixture of E - and Z- olefin isomers that can hinder efforts for the large-scale production and isolation of such complex molecules. To address this issue, we aimed to develop methods that can selectively enrich macrocycles in E - or Z -olefin isomers using an RCM/ethenolysis strategy. The utility of this methodology was demonstrated in the stereoselective formation of macrocyclic peptides, a class of compounds that have gained prominence as therapeutics in drug discovery. Herein, we report an assessment of various factors that promote catalyst-directed RCM and ethenolysis on a variety of peptide substrates by varying the olefin type, peptide sequence, and placement of the olefin in macrocycle formation. These methods allow for control over olefin geometry in peptides, facilitating their isolation and characterization. The studies outlined in this report seek to expand the scope of stereoselective olefin metathesis in general RCM.

  17. Synthesis and Biological Evaluation of a Chitobiose-Based Peptide N-Glycanase Inhibitor Library

    NARCIS (Netherlands)

    Witte, Martin D.; Horst, Danielle; Wiertz, Emmanuel J.H.J.; Marel, Gijsbert A. van der; Overkleeft, Herman S.

    2009-01-01

    Peptide N-glycanase (PNGase), the enzyme responsible for the deglycosylation of N-linked glycoproteins, has an active site related to that of cysteine proteases. Chitiobiose was equipped with electrophilic traps often used in cysteine protease inhibitors, and the resulting compounds were evaluated

  18. Design and synthesis of macrocyclic peptidyl hydroxamates as peptide deformylase inhibitors.

    Science.gov (United States)

    Shen, Gang; Zhu, Jinge; Simpson, Anthony M; Pei, Dehua

    2008-05-15

    Macrocyclic peptidyl hydroxamates were designed, synthesized, and evaluated as peptide deformylase (PDF) inhibitors. The most potent compound exhibited tight, slow-binding inhibition of Escherichia coli PDF (K(I)(*)=4.4 nM) and had potent antibacterial activity against Gram-positive bacterium Bacillus subtilis (MIC=2-4 microg/mL).

  19. The Medicinal Chemistry of Therapeutic Peptides: Recent Developments in Synthesis and Design Optimizations.

    Science.gov (United States)

    Parthasarathy, Anutthaman; Anandamma, Sasikala K; Kalesh, Karunakaran A

    2017-10-12

    Peptide therapeutics have made tremendous progress in the past decade. Many of the inherent weaknesses of peptides which hampered their development as therapeutics are now more or less effectively tackled with recent scientific and technological advancements in integrated drug discovery settings. These include recent developments in synthetic organic chemistry, high-throughput recombinant production strategies, high-resolution analytical methods, high-throughput screening options, ingenious drug delivery strategies and novel formulation preparations. Here, we will briefly describe the key methodologies and strategies used in the therapeutic peptide development processes with select examples of the most recent developments in the field. The aim of this review is to highlight the viable options a medicinal chemist may consider in order to improve a specific pharmacological property of interest in a peptide lead entity and thereby rationally assess the therapeutic potential this class of molecules possesses while they are traditionally (and incorrectly) considered 'undruggable'. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  20. The synthesis of a glucoconjugate of the peptidic fragment of cryptophycin-24

    Directory of Open Access Journals (Sweden)

    Abdelmoumen Mezrai

    2014-07-01

    Full Text Available A novel glucoconjugate of the peptidic fragment of cryptophycin-24 was prepared through the replacement of the leucic acid residue with L-leucine and the functionalisation of tyrosine residue with glucose. Those modifications lead to a novel protected tripeptide fragment of cryptophycin-24.

  1. Synthesis of stable isotopically labeled peptides with filter-assisted enzymatic labeling for the diagnosis of hepatitis B virus infection utilizing mass spectrometry-based proteomics strategy

    International Nuclear Information System (INIS)

    Tsai, Hsing-Fen; Hsiao, He-Hsuan

    2017-01-01

    A facile method for the preparation of stable isotopically labeled peptides was developed by means of filter-assisted tryptic 16 O/ 18 O water labeling, which could be directly applied to the determination of hepatitis B virus infection from human serum with tandem mass spectrometry. Tryptic peptides of hepatitis B surface antigen or hepatitis B e antigen from different subtypes of hepatitis B virus were synthesized with traditional solid-phase peptide synthesis as potential biomarkers. Trypsin catalyzed oxygen-18 exchange at their amidated c-terminus of arginine or lysine residue. The protease catalyzed oxygen-18 to oxygen-16 back exchange reaction was eliminated due to the complete removal of trypsin by the centrifugal filter containing a thin membrane associated with molecular weight cut-off of 10 KDa. The synthetic isotopic peptides were spiked into trichloroacetic acid/acetone precipitated human serum as internal standards and were selectively detected with multiplexed parallel reaction monitoring on a hybrid quadrupole-orbitrap mass spectrometer. The limit of detection for all synthetic peptides were in the range of 0.09 fmol–1.13 fmol. The results indicated that the peptide YLWEWASVR derived from hepatitis B surface antigen was quantified approximately 200 fmol per μl serum and may serve as a diagnostic biomarker for the detection of hepatitis B virus infected disease. - Highlights: • Facile synthesis of an inexpensive and highly reproducible stable isotopically labeled peptides. • Complete incorporation of two 18 O atoms into synthesized peptides with filter-assisted enzymatic labeling. • Targeted analysis with parallel reaction monitoring assay for the disease diagnosis.

  2. Synthesis of stable isotopically labeled peptides with filter-assisted enzymatic labeling for the diagnosis of hepatitis B virus infection utilizing mass spectrometry-based proteomics strategy

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Hsing-Fen; Hsiao, He-Hsuan, E-mail: hhhsiao@dragon.nchu.edu.tw

    2017-03-01

    A facile method for the preparation of stable isotopically labeled peptides was developed by means of filter-assisted tryptic {sup 16}O/{sup 18}O water labeling, which could be directly applied to the determination of hepatitis B virus infection from human serum with tandem mass spectrometry. Tryptic peptides of hepatitis B surface antigen or hepatitis B e antigen from different subtypes of hepatitis B virus were synthesized with traditional solid-phase peptide synthesis as potential biomarkers. Trypsin catalyzed oxygen-18 exchange at their amidated c-terminus of arginine or lysine residue. The protease catalyzed oxygen-18 to oxygen-16 back exchange reaction was eliminated due to the complete removal of trypsin by the centrifugal filter containing a thin membrane associated with molecular weight cut-off of 10 KDa. The synthetic isotopic peptides were spiked into trichloroacetic acid/acetone precipitated human serum as internal standards and were selectively detected with multiplexed parallel reaction monitoring on a hybrid quadrupole-orbitrap mass spectrometer. The limit of detection for all synthetic peptides were in the range of 0.09 fmol–1.13 fmol. The results indicated that the peptide YLWEWASVR derived from hepatitis B surface antigen was quantified approximately 200 fmol per μl serum and may serve as a diagnostic biomarker for the detection of hepatitis B virus infected disease. - Highlights: • Facile synthesis of an inexpensive and highly reproducible stable isotopically labeled peptides. • Complete incorporation of two {sup 18}O atoms into synthesized peptides with filter-assisted enzymatic labeling. • Targeted analysis with parallel reaction monitoring assay for the disease diagnosis.

  3. High-flexibility combinatorial peptide synthesis with laser-based transfer of monomers in solid matrix material.

    Science.gov (United States)

    Loeffler, Felix F; Foertsch, Tobias C; Popov, Roman; Mattes, Daniela S; Schlageter, Martin; Sedlmayr, Martyna; Ridder, Barbara; Dang, Florian-Xuan; von Bojničić-Kninski, Clemens; Weber, Laura K; Fischer, Andrea; Greifenstein, Juliane; Bykovskaya, Valentina; Buliev, Ivan; Bischoff, F Ralf; Hahn, Lothar; Meier, Michael A R; Bräse, Stefan; Powell, Annie K; Balaban, Teodor Silviu; Breitling, Frank; Nesterov-Mueller, Alexander

    2016-06-14

    Laser writing is used to structure surfaces in many different ways in materials and life sciences. However, combinatorial patterning applications are still limited. Here we present a method for cost-efficient combinatorial synthesis of very-high-density peptide arrays with natural and synthetic monomers. A laser automatically transfers nanometre-thin solid material spots from different donor slides to an acceptor. Each donor bears a thin polymer film, embedding one type of monomer. Coupling occurs in a separate heating step, where the matrix becomes viscous and building blocks diffuse and couple to the acceptor surface. Furthermore, we can consecutively deposit two material layers of activation reagents and amino acids. Subsequent heat-induced mixing facilitates an in situ activation and coupling of the monomers. This allows us to incorporate building blocks with click chemistry compatibility or a large variety of commercially available non-activated, for example, posttranslationally modified building blocks into the array's peptides with >17,000 spots per cm(2).

  4. Synthesis and Biological Activities of Some New (Nα-Dinicotinoyl- bis-L-Leucyl Linear and Macrocyclic Peptides

    Directory of Open Access Journals (Sweden)

    Suzan Khayyat

    2014-07-01

    Full Text Available A series of linear and macrocyclic peptides 3–12 were synthesized using 3,5-pyridinedicarboxylic acid (1 as starting material and screened for their antimicrobial, anti-inflammatory and anticancer activities. Bis-ester 3 was prepared from 1 and L-leucine methyl ester. Hydrazinolysis and hydrolysis of dipeptide methyl ester 3 with hydrazine hydrate or 1 N sodium hydroxide afforded compounds 4 and 5, respectively. Cyclization of the dipeptide 5 with L-lysine methyl ester afforded cyclic pentapeptide ester 6. Compounds 7–9 were synthesized by reacting hydrazide 4 with phthalic anhydride, 1,8-naphthalene anhydride or acetophenone derivatives. Treatment of acid hydrazide 4 with aromatic aldehydes or tetraacid dianhydrides afforded the corresponding bis-dipeptide hydrazones 10a–e and macrocyclic peptides 11 and 12, respectively. The structures of newly synthesized compounds were confirmed by IR, 1H-NMR, MS spectral data and elemental analysis. The detailed synthesis, spectroscopic data, biological and pharmacological activities of the synthesized compounds was reported.

  5. Immunoregulatory activities of human immunodeficiency virus (HIV) proteins: Effect of HIV recombinant and synthetic peptides on immunoglobulin synthesis and proliferative responses by normal lymphocytes

    International Nuclear Information System (INIS)

    Nair, M.P.N.; Pottathil, R.; Heimer, E.P.; Schwartz, S.A.

    1988-01-01

    Recombinant and synthetic peptides corresponding to envelope proteins of the human immunodeficiency virus (HIV) were examined for their effects on the activities of lymphocytes from normal donors in vitro. Although lymphocytes cultured with env-gag peptides produced significant amounts of IgG, addition of env-gag peptides to a pokeweed mitogen-induced B-cell activation system resulted in suppression of immunoglobulin synthesis by normal lymphocytes. Recombinant antigens, env-gag and env-80 dihydrofolate reductase (DHFR), produced a substantial proliferative response by peripheral blood mononuclear cells (PBMC) as determined by [ 3 H]thymidine incorporation. PBMC precultured with HIV synthetic peptide env 578-608 also manifested significant proliferative responses as compared to control cultures. CD3 + lymphocytes precultured with recombinant HIV antigens, env-gag and env-80 DHFR, and synthetic HIV peptide, env 487-511, showed moderate but significant proliferative responses. Both recombinant antigens and synthetic peptides also produced a dose-dependent stimulatory effect on proliferation by CD3 - lymphocytes. These studies demonstrate that recombinant and synthetic peptides of the HIV genome express immunoregulatory T- and B-cell epitopes. Identification of unique HIV epitopes with immunogenic and immunoregulatory activities is necessary for the development of an effective vaccine against HIV infection

  6. Solid-Phase Synthesis of Modified Peptides as Putative Inhibitors of Histone Modifying Enzymes

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil O'Hanlon

    The role of histone modifications in the tight regulation of gene expression is emerging as a new area within drug discovery. The misregulation of histone modification levels has been linked with several life-threatening diseases, including cancer and diabetes, and reverting these irregularities...... may improve the prognosis of patients suffering from these diseases. The development of methodologies to modify peptides for use as peptide-based inhibitors of histone modifying enzymes is presented. Several different approaches for both N and C-terminal modification have been developed. Two broadly......,2,3-triazoles were cleanly deprotected by treatment with TFA (CH2Cl2). Four different libraries of histone demethylase inhibitor candidates have been synthesised based on metal chelation, cofactor mimicking and radial stabilising inhibition strategies. The libraries have all been synthesised on solid...

  7. Development and evaluation of a non-ribosomal random PCR and next-generation sequencing based assay for detection and sequencing of hand, foot and mouth disease pathogens.

    Science.gov (United States)

    Nguyen, Anh To; Tran, Thanh Tan; Hoang, Van Minh Tu; Nghiem, Ngoc My; Le, Nhu Nguyen Truc; Le, Thanh Thi My; Phan, Qui Tu; Truong, Khanh Huu; Le, Nhan Nguyen Thanh; Ho, Viet Lu; Do, Viet Chau; Ha, Tuan Manh; Nguyen, Hung Thanh; Nguyen, Chau Van Vinh; Thwaites, Guy; van Doorn, H Rogier; Le, Tan Van

    2016-07-07

    Hand, foot and mouth disease (HFMD) has become a major public health problem across the Asia-Pacific region, and is commonly caused by enterovirus A71 (EV-A71) and coxsackievirus A6 (CV-A6), CV-A10 and CV-A16. Generating pathogen whole-genome sequences is essential for understanding their evolutionary biology. The frequent replacements among EV serotypes and a limited numbers of available whole-genome sequences hinder the development of overlapping PCRs for whole-genome sequencing. We developed and evaluated a non-ribosomal random PCR (rPCR) and next-generation sequencing based assay for sequence-independent whole-genome amplification and sequencing of HFMD pathogens. A total of 16 EV-A71/CV-A6/CV-A10/CV-A16 PCR positive rectal/throat swabs (Cp values: 20.9-33.3) were used for assay evaluation. Our assay evidently outperformed the conventional rPCR in terms of the total number of EV-A71 reads and the percentage of EV-A71 reads: 2.6 % (1275/50,000 reads) vs. 0.1 % (31/50,000) and 6 % (3008/50,000) vs. 0.9 % (433/50,000) for two samples with Cp values of 30 and 26, respectively. Additionally the assay could generate genome sequences with the percentages of coverage of 94-100 % of 4 different enterovirus serotypes in 73 % of the tested samples, representing the first whole-genome sequences of CV-A6/10/16 from Vietnam, and could assign correctly serotyping results in 100 % of 24 tested specimens. In all but three the obtained consensuses of two replicates from the same sample were 100 % identical, suggesting that our assay is highly reproducible. In conclusion, we have successfully developed a non-ribosomal rPCR and next-generation sequencing based assay for sensitive detection and direct whole-genome sequencing of HFMD pathogens from clinical samples.

  8. Use of FTIR in the obtention of resins and peptides synthesis in solid phase; Uso da FTIR na obtencao de resinas e na sintese de peptideos em fase solida

    Energy Technology Data Exchange (ETDEWEB)

    Cespedes, Graziely Ferreira; Vicente, Eduardo Festozo; Cilli, Eduardo Maffud, E-mail: cilli@iq.unesp.b [Universidade Estadual Paulista (IQ/UNESP), Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Bioquimica e Tecnologia Quimica; Jubilut, Guita Nicolaewsky; Nakaie, Clovis Ryuichi [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Biofisica

    2011-07-01

    Despite the increase in peptide chain aggregation, which decreases the rate of coupling reactions, the synthesis and use of very highly substituted resins still remains as a controversial point in the SPPS, due to its clear economical advantages (lesser solvent consumption and higher amount of peptide per synthesis). In order to better investigate the synthesis and the use of very highly substituted resins, the FTIR, NMR and EPR were compared. By FTIR techniques it was possible to follow all the steps of resin synthesis and the factors affecting the aggregation of the chains inside the peptidil-BHAR and MBHAR. (author)

  9. Peptide-steroids chimeras synthesis and visualization of their binding to the rat brain slices

    Czech Academy of Sciences Publication Activity Database

    Jurasek, M.; Flegel, Martin; Skopek, P.; Flegelová, Z.; Drasar, P.; Hynie, S.; Klenerová, V.

    2012-01-01

    Roč. 18, S1 (2012), S123-S123 ISSN 1075-2617. [European Peptide Symposium /32./. 02.09.2012-07.09.2012, Athens] R&D Projects: GA MŠk(CZ) 7E11071 EU Projects: European Commission(XE) 245122 - DINAMO Grant - others:PRVOUK(CZ) P25/LF1/2; GA UK(CZ) 85210; GA UK(CZ) SVV 264514; GA AV ČR(CZ) KAN200100801 Program:KA Institutional research plan: CEZ:AV0Z40550506 Keywords : oxytocin * chimeras * steroids * binding sites Subject RIV: CE - Biochemistry

  10. Mathematical determination of kinetic parameters for assessing the effect of the organic solvent on the selectivity of peptide synthesis with immobilized α-chymotrypsin.

    Science.gov (United States)

    Bahamondes, Carola; Wilson, Lorena; Guzmán, Fanny; Illanes, Andrés

    2017-12-01

    The synthesis of the dipeptide N-benzoyl-l-tyrosine-l-argininamide (BTAA) was conducted under kinetic control with N-benzoyl-l-tyrosine ethyl ester as acyl donor and argininamide as nucleophile using immobilized α-chymotrypsin as catalyst. Using a mathematical procedure, the kinetic constants corresponding to the proposed mechanism of peptide synthesis were determined in three different cosolvent media, namely, ethanol, diglyme and acetonitrile. These constants were used for evaluating the selectivity of glyoxyl-agarose immobilized α-chymotrypsin in the synthesis of BTAA by determining the ratios of synthesis to hydrolysis rates. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  11. Synthesis and bioactivities study of new antibacterial peptide mimics: The dialkyl cationic amphiphiles.

    Science.gov (United States)

    Zhang, En; Bai, Peng-Yan; Cui, De-Yun; Chu, Wen-Chao; Hua, Yong-Gang; Liu, Qin; Yin, Hai-Yang; Zhang, Yong-Jie; Qin, Shangshang; Liu, Hong-Min

    2018-01-01

    The emergence of infectious diseases caused by pathogenic bacteria is widespread. Therefore, it is urgently required to enhance the development of novel antimicrobial agents with high antibacterial activity and low cytotoxicity. A series of novel dialkyl cationic amphiphiles bearing two identical length lipophilic alkyl chains and one non-peptidic amide bond were synthesized and tested for antimicrobial activities against both Gram-positive and Gram-negative bacteria. Particular compounds synthesized showed excellent antibacterial activity toward drug-sensitive bacteria such as S. aureus, E. faecalis, E. coli and S. enterica, and clinical isolates of drug-resistant species such as methicillin-resistant S. aureus (MRSA), KPC-producing and NDM-1-producing carbapenem-resistant Enterobacteriaceae (CRE). For example, the MIC values of the best compound 4g ranged from 0.5 to 2 μg/mL against all these strains. Moreover, these small molecules acted rapidly as bactericidal agents, and functioned primarily by permeabilization and depolarization of bacterial membranes. Importantly, these compounds were difficult to induce bacterial resistance and can potentially combat drug-resistant bacteria. Thus, these compounds can be developed into a new class of antibacterial peptide mimics against Gram-positive and Gram-negative bacteria, including drug-resistant bacterial strains. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  12. Self-assembled peptide template directed synthesis of one-dimensional inorganic nanostructures and their applications

    OpenAIRE

    Acar, Handan

    2012-01-01

    Ankara : The Materials Science and Nanotechnology Program of the Graduate School of Engineering and Sciences of Bilkent University, 2012. Thesis (Ph. D.) -- Bilkent University, 2012. Includes bibliographical references. Engineering at the nano scale has been an active area of science and technology over the last decade. Inspired by nature, synthesis of functional inorganic materials using synthetic organic templates constitutes the theme of this thesis. Developing organic te...

  13. Exploiting 1,2,3-Triazolium Ionic Liquids for Synthesis of Tryptanthrin and Chemoselective Extraction of Copper(II) Ions and Histidine-Containing Peptides.

    Science.gov (United States)

    Li, Hsin-Yi; Chen, Chien-Yuan; Cheng, Hui-Ting; Chu, Yen-Ho

    2016-10-13

    Based on a common structural core of 4,5,6,7-tetrahydro[1,2,3]triazolo[1,5- a ]pyridine, a number of bicyclic triazolium ionic liquids 1 - 3 were designed and successfully prepared. In our hands, this optimized synthesis of ionic liquids 1 and 2 requires no chromatographic separation. Also in this work, ionic liquids 1 , 2 were shown to be efficient ionic solvents for fast synthesis of tryptanthrin natural product. Furthermore, a new affinity ionic liquid 3 was tailor-synthesized and displayed its effectiveness in chemoselective extraction of both Cu(II) ions and, for the first time, histidine-containing peptides.

  14. Synthesis of Peptides from α- and β-Tubulin Containing Glutamic Acid Side-Chain Linked Oligo-Glu with Defined Length

    Directory of Open Access Journals (Sweden)

    Werner Tegge

    2010-01-01

    Full Text Available Side-chain oligo- and polyglutamylation represents an important posttranslational modification in tubulin physiology. The particular number of glutamate units is related to specific regulatory functions. In this work, we present a method for the synthesis of building blocks for the Fmoc synthesis of peptides containing main chain glutamic acid residues that carry side-chain branching with oligo-glutamic acid. The two model peptide sequences CYEEVGVDSVEGEG-E(E-EEGEEY and CQDATADEQG-E(E-FEEEEGEDEA from the C-termini of mammalian α1- and β1-tubulin, respectively, containing oligo-glutamic acid side-chain branching with lengths of 1 to 5 amino acids were assembled in good yield and purity. The products may lead to the generation of specific antibodies which should be important tools for a more detailed investigation of polyglutamylation processes.

  15. Solid phase synthesis of Smac/DIABLO-derived peptides using a 'Safety-Catch' resin: identification of potent XIAP BIR3 antagonists.

    Science.gov (United States)

    Elsawy, Mohamed A; Martin, Lorraine; Tikhonova, Irina G; Walker, Brian

    2013-09-01

    The N-terminal sequence of the Smac/DIABLO protein is known to be involved in binding to the BIR3 domain of the anti-apoptotic proteins IAPs, antagonizing their action. Short peptides and peptide mimetics based on the first 4-residues of Smac/DIABLO have been demonstrated to re-sensitize resistant cancer cells, over-expressing IAPs, to apoptosis. Based on the well-defined structural basis for this interaction, a small focused library of C-terminal capped Smac/DIABLO-derived peptides was designed in silico using docking to the XIAP BIR3 domain. The top-ranked computational hits were conveniently synthesized employing Solid Phase Synthesis (SPS) on an alkane sulfonamide 'Safety-Catch' resin. This novel approach afforded the rapid synthesis of the target peptide library with high flexibility for the introduction of various C-terminal amide-capping groups. The library members were obtained in high yield (>65%) and purity (>85%), upon nucleophilic release from the activated resin by treatment with various amine nucleophiles. In vitro caspase-9 activity reconstitution assays of the peptides in the presence of the recombinant BIR3-domain of human XIAP (500nM) revealed N-methylalanyl-tertiarybutylglycinyl-4-(R)-phenoxyprolyl-N-biphenylmethyl carboxamide (11a) to be the most potent XIAP BIR3 antagonist of the series synthesized inducing 93% recovery of caspase-9 activity, when used at 1μM concentration. Compound (11a) also demonstrated moderate cytotoxicity against the breast cancer cell lines MDA-MB-231 and MCF-7, compared to the Smac/DIABLO-derived wild-type peptide sequences that were totally inactive in the same cell lines. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Helical polymer carrying helical grafts from peptide-based acetylene macromonomers: synthesis.

    Science.gov (United States)

    Sanda, Fumio; Gao, Guangzheng; Masuda, Toshio

    2004-06-25

    N-Propargylamide-terminated peptide-based macromonomers with a degree of polymerization ranging from 4 to 40 were synthesized by the polymerization of gamma-benzyl and gamma-stearyl-L-glutamate-N-carboxy anhydrides initiated with propargylamine. The macromonomers took an alpha-helical structure, which was confirmed by signals at 208 and 220 nm in CD spectra. The macromonomers were subjected to polymerization and copolymerization with an alanine-derived N-propargylamide [N-(tert-butoxycarbonyl)-L-alanine-N'-propargylamide] catalyzed with (2,5-norbornadiene)Rh+[eta6-C6H5B- (C6H5)3]. It was confirmed through a CD spectroscopic study that the copolymer obtained from the copolymerization of the gamma-stearyl-L-glutamate-based macromonomer with the alanine-derived N-propargylamide had a helical polyacetylene main chain and helical polypeptide side chains.

  17. Synthesis of biotinyl derivatives of peptide hormones and other biological materials

    International Nuclear Information System (INIS)

    Finn, F.M.; Hofmann, K.H.

    1985-01-01

    Methods for the preparation of biotinylated ligands for the avidin-biotin system are described. Also described are procedures for modifying and labelling avidin and for assessing the rate of dissociation of biotin derivatives from avidin. The most widely used procedure for introducing biotin into other molecules involves acylation with N-hydroxysuccinimido-biotinate. Experimental details are given for the synthesis of dethiobiotin, iminobiotin, and biotinylated ligands in which a 6-aminohexanoic acid spacer is interposed between the biotin or biotin derivative and the insulin molecule. The syntheses of biotinylated corticotropins are presented only in principle

  18. Pyrrhocoricin, a proline-rich antimicrobial peptide derived from insect, inhibits the translation process in the cell-free Escherichia coli protein synthesis system.

    Science.gov (United States)

    Taniguchi, Masayuki; Ochiai, Akihito; Kondo, Hiroshi; Fukuda, Shun; Ishiyama, Yohei; Saitoh, Eiichi; Kato, Tetsuo; Tanaka, Takaaki

    2016-05-01

    Previous studies have shown that pyrrhocoricin, a proline-rich antimicrobial peptide (PrAMP), killed sensitive species in a dose-dependent manner by specifically binding to DnaK. Here, on the basis of the finding that DnaK-deficient Escherichia coli strains are susceptible to PrAMPs, we used pyrrhocoricin to investigate internal targets other than DnaK. Using conventional antibiotics (bleomycin, streptomycin, and fosfomycin) that have known modes of action, first, we validated the availability of an assay using a cell-free rapid translation system (RTS), which is an in vitro protein synthesis system based on E. coli lysate, for evaluating inhibition of protein synthesis. We found that, similarly to bleomycin and streptomycin, pyrrhocoricin inhibited GFP synthesis in RTS in a concentration-dependent manner. In addition, blockage of transcription and translation steps in RTS was individually estimated using RT-PCR after gene expression to determine mRNA products and using sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine the amounts of GFP expressed from purified mRNA, respectively. The results demonstrated that this inhibition of GFP synthesis by pyrrhocoricin did not occur at the transcription step but rather at the translation step, in a manner similar to that of GFP synthesis by streptomycin, an inhibitor of the translation step by causing misreading of tRNA. These results suggest that RTS is a powerful assay system for determining if antimicrobial peptides inhibit protein synthesis and its transcription and/or translation steps. This is the first study to have shown that pyrrhocoricin inhibited protein synthesis by specifically repressing the translation step. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  19. Bacterial Peptide Deformylase Inhibition of Tetrazole-Substituted Biaryl Acid Analogs: Synthesis, Biological Evaluations, and Molecular Docking Study.

    Science.gov (United States)

    Khan, Firoz A Kalam; Patil, Rajendra H; Patil, Manjiri; Arote, Rohidas; Shinde, Devanand B; Sangshetti, Jaiprakash N

    2016-12-01

    The synthesis and screening of tetrazole-substituted biaryl acid analogs 7a-l as bacterial peptide deformylase (PDF) enzyme inhibitors is reported. The compounds 7e (IC 50 value = 5.50 μM) and 7g (IC 50 value = 7.25 μM) showed good PDF inhibition activity. The compounds 7e (MIC range = 10.75-11.66 μg/mL) and 7g (MIC range = 8.91-12.83 μg/mL) also showed potent antibacterial activity when compared with the standard ciprofloxacin (MIC range = 25-50 μg/mL). Thus, the active derivatives were not only potent PDF enzyme inhibitors but also efficient antibacterial agents. In order to gain more insight into the binding mode of the compounds with the PDF enzyme, the most active compounds 7e and 7g, the moderately active compound 7k, and the least active compound 7h were docked against the PDF enzyme of Escherichia coli. The docking study of the most active compounds 7e and 7g against the PDF enzyme exhibited good binding properties. Hence, we believe our synthesized compounds 7a-l could serve as reservoir for bacterial PDF inhibitor development. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Amino-acid- and peptide-directed synthesis of chiral plasmonic gold nanoparticles.

    Science.gov (United States)

    Lee, Hye-Eun; Ahn, Hyo-Yong; Mun, Jungho; Lee, Yoon Young; Kim, Minkyung; Cho, Nam Heon; Chang, Kiseok; Kim, Wook Sung; Rho, Junsuk; Nam, Ki Tae

    2018-04-01

    Understanding chirality, or handedness, in molecules is important because of the enantioselectivity that is observed in many biochemical reactions 1 , and because of the recent development of chiral metamaterials with exceptional light-manipulating capabilities, such as polarization control 2-4 , a negative refractive index 5 and chiral sensing 6 . Chiral nanostructures have been produced using nanofabrication techniques such as lithography 7 and molecular self-assembly 8-11 , but large-scale and simple fabrication methods for three-dimensional chiral structures remain a challenge. In this regard, chirality transfer represents a simpler and more efficient method for controlling chiral morphology 12-18 . Although a few studies 18,19 have described the transfer of molecular chirality into micrometre-sized helical ceramic crystals, this technique has yet to be implemented for metal nanoparticles with sizes of hundreds of nanometres. Here we develop a strategy for synthesizing chiral gold nanoparticles that involves using amino acids and peptides to control the optical activity, handedness and chiral plasmonic resonance of the nanoparticles. The key requirement for achieving such chiral structures is the formation of high-Miller-index surfaces ({hkl}, h ≠ k ≠ l ≠ 0) that are intrinsically chiral, owing to the presence of 'kink' sites 20-22 in the nanoparticles during growth. The presence of chiral components at the inorganic surface of the nanoparticles and in the amino acids and peptides results in enantioselective interactions at the interface between these elements; these interactions lead to asymmetric evolution of the nanoparticles and the formation of helicoid morphologies that consist of highly twisted chiral elements. The gold nanoparticles that we grow display strong chiral plasmonic optical activity (a dis-symmetry factor of 0.2), even when dispersed randomly in solution; this observation is supported by theoretical calculations and direct

  1. A convenient and highly efficient synthesis of one kind of peptide nucleic acid monomer

    Directory of Open Access Journals (Sweden)

    Xuemei Tang

    2012-12-01

    Full Text Available S-Thyminyl-L-cysteine methyl ester hydrochloride (compound 1, a non-classical peptide nucleic acid monomer, was synthesized through the key intermediate, N-tert- butoxycarbonyl-S-thyminyl-L-cysteine (compound 3, which afforded from the reaction of S-thyminyl-L-cysteine hydrochloride (compound 2 with di-tert-butyl dicarbonate (Boc2O. This was followed by the esterification and deprotection of compound 3 at an overall yield of 82%. The mixture of thionyl chloride and methanol was found as an efficient reagent for simultaneous deprotection of tert-butoxycarbonyl (Boc group and esterification of carboxy group of compound 3. This high-yield two-step method was also applied to other analogues of compound 1 successfully. The chemical structures of four new compounds (5a-5d were confirmed by 1H NMR and 13C NMR.DOI: http://dx.doi.org/10.4314/bcse.v26i3.10

  2. Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label

    Directory of Open Access Journals (Sweden)

    Nattawut Yotapan

    2014-09-01

    Full Text Available DNA or its analogues with an environment-sensitive fluorescent label are potentially useful as a probe for studying the structure and dynamics of nucleic acids. In this work, pyrrolidinyl peptide nucleic acid (acpcPNA was labeled at its backbone with Nile red, a solvatochromic benzophenoxazine dye, by means of click chemistry. The optical properties of the Nile red-labeled acpcPNA were investigated by UV–vis and fluorescence spectroscopy in the absence and in the presence of DNA. In contrast to the usual quenching observed in Nile red-labeled DNA, the hybridization with DNA resulted in blue shifting and an enhanced fluorescence regardless of the neighboring bases. More pronounced blue shifts and fluorescence enhancements were observed when the DNA target carried a base insertion in close proximity to the Nile red label. The results indicate that the Nile red label is located in a more hydrophobic environment in acpcPNA–DNA duplexes than in the single-stranded acpcPNA. The different fluorescence properties of the acpcPNA hybrids of complementary DNA and DNA carrying a base insertion are suggestive of different interactions between the Nile red label and the duplexes.

  3. Enzymatic synthesis of quaternary ammonium chitosan-silk fibroin peptide copolymer and its characterization.

    Science.gov (United States)

    Min, Lian; Liu, Meng; Liu, Liangling; Rao, Ziqie; Zhu, Chen; Fan, Lihong

    2018-04-01

    Free radicals are closely related to the occurrence and development of aging, cancer and inflammation. The aim of the present study was to improve the antioxidant effects of quaternary ammonium chitosan (QCS) by modified with silk fibroin peptide (SFP). The modification had been confirmed by FT-IR and 1 H NMR spectroscopy. Degree of substitution (DS) of QCS-SFP could be controlled by adjusting the reaction conditions. In this paper, the results of moisture absorption and retention test showed that QCS-SFP had excellent moisture absorption and retention properties. In vitro antioxidant activity assays demonstrated that, with the DS and concentration increasing of QCS-SFP, the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, hydroxyl radical and hydrogen peroxide (H 2 O 2 ) increased. Furthermore, the methyl thiazolyl tetrazolium assay (MTT) was applied to evaluate the biocompatibility of QCS-SFP, and the result indicated that QCS-SFP with the DS of 0.32 displayed pronounced cell viability at 100ppm. These results suggested that QCS-SFP would appear to be a promising candidate for wound dressing application. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. A functional mimic of natural peroxidases : synthesis and catalytic activity of a non-heme iron peptide hydroperoxide complex

    NARCIS (Netherlands)

    Choma, CT; Schudde, EP; Kellogg, RM; Robillard, GT; Feringa, BL

    1998-01-01

    Site-selective attachment of unprotected peptides to a non-heme iron complex is achieved by displacing two halides on the catalyst by peptide caesium thiolates, This coupling approach should be compatible with any peptide sequence provided there is only a single reduced cysteine. The oxidation

  5. Synthesis of peptide-immunogens corresponding to amino acid sequences from human histocompatibility class II membrane glycoproteins.

    Science.gov (United States)

    Chillemi, F; Cappelletti, S; Francescato, P; Chersi, A

    1990-03-01

    Six peptides with amino acid sequences of human histocompatibility Class II membrane glycoproteins were synthesized by conventional solution methods. Five peptides were prepared by stepwise procedures from the carboxyterminus. The sixth was synthesized by fragment condensation (5 + 10 coupling). Antibodies to synthetic peptides were then used to locate exposed and buried regions in the membrane glycoproteins.

  6. Synthesis and characterization of designed BMHP1-derived self-assembling peptides for tissue engineering applications.

    Science.gov (United States)

    Silva, Diego; Natalello, Antonino; Sanii, Babak; Vasita, Rajesh; Saracino, Gloria; Zuckermann, Ronald N; Doglia, Silvia Maria; Gelain, Fabrizio

    2013-01-21

    The importance of self-assembling peptides (SAPs) in regenerative medicine is becoming increasingly recognized. The propensity of SAPs to form nanostructured fibers is governed by multiple forces including hydrogen bonds, hydrophobic interactions and π-π aromatic interactions among side chains of the amino acids. Single residue modifications in SAP sequences can significantly affect these forces. BMHP1-derived SAPs is a class of biotinylated oligopeptides, which self-assemble in β-structured fibers to form a self-healing hydrogel. In the current study, selected modifications in previously described BMHP1-derived SAPs were designed in order to investigate the influence of modified residues on self-assembly kinetics and scaffold formation properties. The Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis demonstrated the secondary structure (β-sheet) formation in all modified SAP sequences, whereas atomic force microscopy (AFM) analysis further confirmed the presence of nanofibers. Furthermore, the fiber shape and dimension analysis by AFM showed flattened and twisted fiber morphology ranging from ∼8 nm to ∼70 nm. The mechanical properties of the pre-assembled and post assembled solution were investigated by rheometry. The shear-thinning behavior and rapid re-healing properties of the pre-assembled solutions make them a preferable choice for injectable scaffolds. The wide range of stiffnesses (G')--from ∼1000 to ∼27,000 Pa--exhibited by the post-assembled scaffolds demonstrated their potential for a variety of tissue engineering applications. The extra cellular matrix (ECM) mimicking (physically and chemically) properties of SAP scaffolds enhanced cell adhesion and proliferation. The capability of the scaffold to facilitate murine neural stem cell (mNSC) proliferation was evaluated in vitro: the increased mNSCs adhesion and proliferation demonstrated the potential of newly synthesized SAPs for regenerative medicine

  7. On-resin N-formylation of peptides: a head-to-head comparison of reagents in solid-phase synthesis of ligands for formyl peptide receptors

    DEFF Research Database (Denmark)

    Christensen, Simon Bendt; Hansen, Anna Mette; Franzyk, Henrik

    2017-01-01

    General conditions for efficient on-resin N-formylation of peptides were identified by screening of a number of reagents comprising aliphatic formates (ethyl formate, 2,2,2-trifluoroethyl formate, and cyanomethyl formate), aromatic esters (phenyl formate and p-nitrophenyl formate), and N-formylim......General conditions for efficient on-resin N-formylation of peptides were identified by screening of a number of reagents comprising aliphatic formates (ethyl formate, 2,2,2-trifluoroethyl formate, and cyanomethyl formate), aromatic esters (phenyl formate and p-nitrophenyl formate), and N......-formylimidazole and in situ activation of formic acid with the coupling reagent 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. Initially, reaction time and influence of solvent were examined for the formylation of a short model peptide. The most efficient reagents were examined further by using different linkers and solid...

  8. Sterically hindered C(alpha, alpha)-disubstituted alpha-amino acids: synthesis from alpha-nitroacetate and incorporation into peptides.

    Science.gov (United States)

    Fu, Y; Hammarström, L G; Miller, T J; Fronczek, F R; McLaughlin, M L; Hammer, R P

    2001-10-19

    The preparation of sterically hindered and polyfunctional C(alpha,alpha)-disubstituted alpha-amino acids (alpha alpha AAs) via alkylation of ethyl nitroacetate and transformation into derivatives ready for incorporation into peptides are described. Treatment of ethyl nitroacetate with N,N-diisopropylethylamine (DIEA) in the presence of a catalytic amount of tetraalkylammonium salt, followed by the addition of an activated alkyl halide or Michael acceptor, gives the doubly C-alkylated product in good to excellent yields. Selective nitro reduction with Zn in acetic acid or hydrogen over Raney Ni gives the corresponding amino ester that, upon saponification, can be protected with the fluorenylmethyloxycarbonyl (Fmoc) group. The first synthesis of an orthogonally protected, tetrafunctional C(alpha,alpha)-disubstituted analogue of aspartic acid, 2,2-bis(tert-butylcarboxymethyl)glycine (Bcmg), is described. Also, the sterically demanding C(alpha,alpha)-dibenzylglycine (Dbg) has been incorporated into a peptide using solid-phase synthesis. It was found that once sterically congested Dbg is at the peptide N-terminus, further chain extension becomes very difficult using uronium or phosphonium salts (PyAOP, PyAOP/HOAt, HATU). However, preformed amino acid symmetrical anhydride couples to N-terminal Dbg in almost quantitative yield in nonpolar solvent (dichloroethane-DMF, 9:1).

  9. Synthesis, characterization, X-ray crystallography, and cytotoxicity of a cymantrene keto carboxylic acid for IR labelling of bioactive peptides on a solid support.

    Science.gov (United States)

    Peindy N'Dongo, Harmel W; Neundorf, Ines; Merz, Klaus; Schatzschneider, Ulrich

    2008-12-01

    Cym-CO-CH2-CH2-COOH was prepared in good yield by Friedel-Crafts reaction of cymantrene (Cym, CpMn(CO)3) with succinic anhydride for the IR labelling of peptides and fully characterized, including an X-ray structure analysis (monoclinic space group P2(1)/n, a=5.727(3)A, b=19.865(9)A, c=10.518(5)A, beta=91.211(9) degrees). The compound was isolated in pure form without the need for chromatographic work-up and subsequently used for solution-phase synthesis of a bioconjugate with phenylalanine methyl ester to allow a complete spectroscopic characterization of this model system. The cymantrene keto carboxylic acid also turned out to be a very robust marker in automated microwave-assisted solid phase peptide synthesis (SPPS). [Leu5]-enkephalin (Tyr-Gly-Gly-Phe-Leu) was prepared on a Wang resin and labelled with the cymantrene derivative on the solid support under microwave irradiation in all steps. The metal-carbonyl marker stayed intact during cleavage from the resin with concentrated trifluoroacetic acid. After simple precipitation and lyophilization, the cymantrene-enkephalin bioconjugate could be obtained in analytically pure form without the need of HPLC purification. As required, the compound is non-cytotoxic against MCF-7 cells at up to 100 microM. This protocol thus allows one to introduce organometallic IR spectroscopic labels to peptides in a very straightforward way.

  10. Laccase mediated-synthesis of hydroxycinnamoyl-peptide from ferulic acid and carnosine.

    Science.gov (United States)

    Aljawish, Abdulhadi; Chevalot, Isabelle; Madad, Nidal; Paris, Cédric; Muniglia, Lionel

    2016-06-10

    Carnosine (CAR) dipeptide was functionalized with ferulic acid (FA) as substrate using laccase from Myceliophtora thermophila as biocatalyst. The enzymatic reaction was performed in aqueous medium under mild conditions (pH 7.5, 30°C) as an eco-friendly procedure. Results showed that this enzymatic process led to the synthesis of two new derivatives (P1, P2), from the coupling between CAR and FA derived products. Conditions allowing a high production of P1, P2 derivatives were determined with an optimal ratio of (FA: CAR) of (1:1.6) at optimal time reaction of 8h. Under these optimal conditions, the coupling between CAR and FA-products was demonstrated, resulting in the decrease of -NH2 groups (almost 50%) as quantified via derivatization. Due to the presence of FA in the structure of these new derivatives, they exhibited higher hydrophobic property than carnosine. Structural analyses by mass spectrometry showed that P1 and P2 (FA-CAR) derivatives exhibited the same molecular mass (MM 770g/mol) containing one CAR-molecule and three FA-molecules but with different chemical structures. Furthermore, these derivatives presented improved antioxidant (almost 10 times) and anti-proliferative (almost 18 times) properties in comparison with CAR. Moreover, P1 derivative exhibited higher antioxidant and anti-proliferative activities than P2 derivative, which confirmed the different structures of P1 and P2. These results suggested that the oxidized phenols coupling with carnosine is a promising process to enhance the CAR-properties. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Proinsulin C-peptide potentiates the inhibitory action of insulin on glucose synthesis in primary cultured rabbit kidney-cortex tubules: metabolic studies.

    Science.gov (United States)

    Usarek, Michal; Jagielski, Adam Konrad; Krempa, Paulina; Dylewska, Anna; Kiersztan, Anna; Drozak, Jakub; Girstun, Agnieszka; Derlacz, Rafal Andrzej; Bryla, Jadwiga

    2014-02-01

    Effects of equimolar concentrations of proinsulin C-peptide and insulin on glucose synthesis were studied in primary cultures of rabbit kidney-cortex tubules grown in the presence of alanine, glycerol, and octanoate. The rhodamine-labeled C-peptide entered renal tubular cells and localized in nuclei, both in the presence and absence of insulin; preincubations with the unlabeled compound inhibited internalization. C-peptide did not affect glucose formation when added alone but potentiated the inhibitory action of insulin by about 20% due to a decrease in flux through glucose-6-phosphate isomerase (GPI) and (or) glucose-6-phosphatase (G6Pase). GPI inhibition was caused by: (i) increased intracellular contents of fructose-1,6-bisphosphate and fructose-1-phosphate, inhibitors of the enzyme and (ii) reduced level of the phosphorylated GPI, which exhibits higher enzymatic activity in the presence of casein kinase 2. A decrease in flux through G6Pase, due to diminished import of G6P by G6P-transporter from the cytoplasm into endoplasmic reticulum lumen, is also suggested. The data show for the first time that in the presence of insulin and C-peptide, both GPI and G6P-ase may act as regulatory enzymes of renal gluconeogenic pathway.

  12. Development of a seaweed derived platelet activating factor acetylhydrolase (PAF-AH) inhibitory hydrolysate, synthesis of inhibitory peptides and assessment of their toxicity using the Zebrafish larvae assay.

    Science.gov (United States)

    Fitzgerald, Ciarán; Gallagher, Eimear; O'Connor, Paula; Prieto, José; Mora-Soler, Leticia; Grealy, Maura; Hayes, Maria

    2013-12-01

    The vascular inflammatory role of platelet activating factor acetylhydrolase (PAF-AH) is thought to be due to the formation of lysophosphatidyl choline and oxidized non-esterified fatty acids. This enzyme is considered a promising therapeutic target for the prevention of atherosclerosis and there is a need to expand the available chemical templates of PAF-AH inhibitors. This study demonstrated how natural PAF-AH inhibitory peptides were isolated and characterized from the red macroalga Palmaria palmata. The dried powdered alga was hydrolyzed using the food grade enzyme papain, and the resultant peptide containing fraction generated using RP-HPLC. Several oligopeptides were identified as potential PAF-AH inhibitors following bio-guided fractionation, and the amino acid sequences of these oligopeptides were confirmed by Q-TOF-MS and microwave-assisted solid phase de novo synthesis. The most promising PAF-AH inhibitory peptide had the amino acid sequence NIGK and a PAF-AH IC50 value of 2.32 mM. This peptide may constitute a valid drug template for PAF-AH inhibitors. Furthermore the P. palmata hydrolysate was nontoxic when assayed using the Zebrafish toxicity model at a concentration of 1mg/ml. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Synthesis and Characterization of a Gd-DOTA-D-Permeation Peptide for Magnetic Resonance Relaxation Enhancement of Intracellular Targets

    Directory of Open Access Journals (Sweden)

    Andrew M. Prantner

    2003-10-01

    Full Text Available Many MR contrast agents have been developed and proven effective for extracellular nontargeted applications, but exploitation of intracellular MR contrast agents has been elusive due to the permeability barrier of the plasma membrane. Peptide transduction domains can circumvent this permeability barrier and deliver cargo molecules to the cell interior. Based upon enhanced cellular uptake of permeation peptides with D-amino acid residues, an all-D Tat basic domain peptide was conjugated to DOTA and chelated to gadolinium. Gd-DOTA-D-Tat peptide in serum at room temperature showed a relaxivity of 7.94 ± 0.11 mM−1 sec−1 at 4.7 T. The peptide complex displayed no significant binding to serum proteins, was efficiently internalized by human Jurkat leukemia cells resulting in intracellular T1 relaxation enhancement, and in preliminary T1-weighted MRI experiments, significantly enhanced liver, kidney, and mesenteric signals.

  14. Antimicrobial Peptides in 2014

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2015-03-01

    Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.

  15. Novel peptides with tyrosinase inhibitory activity

    NARCIS (Netherlands)

    Schurink, M.; Berkel, van W.J.H.; Wichers, H.J.; Boeriu, C.G.

    2007-01-01

    Tyrosinase inhibition by peptides may find its application in food, cosmetics or medicine. In order to identify novel tyrosinase inhibitory peptides, protein-based peptide libraries made by SPOT synthesis were used to screen for peptides that show direct interaction with tyrosinase. One of the

  16. A Multidisciplinary Workshop: Self-Assembling Peptide Systems in Biology, Medicine and Engineering, Crete, Greece, July 1-6, 1999

    Science.gov (United States)

    1999-07-06

    Nanoparticles on Self- Assembled Biolipid Tubular Templates." Chem. Commun., 1996, 321-322. 4. S. L. Burkett, S. D. Sims, and S. Mann, "Synthesis of...exploitation of biocatalysis, ribosomal and non-ribosomal biosynthesis to enhance permissiveness toward elaboration of useful biomolecular structures and...1999).L. Bromberg, I. Lewin, H. Gottlieb and A. Warshawsky Interaction of mercury (II) and silver (I) with bis[di(2-ethylhexyloxy)- thiophosphoryl

  17. Isolation, synthesis and characterization of ω-TRTX-Cc1a, a novel tarantula venom peptide that selectively targets L-type Cav channels.

    Science.gov (United States)

    Klint, Julie K; Berecki, Géza; Durek, Thomas; Mobli, Mehdi; Knapp, Oliver; King, Glenn F; Adams, David J; Alewood, Paul F; Rash, Lachlan D

    2014-05-15

    Spider venoms are replete with peptidic ion channel modulators, often with novel subtype selectivity, making them a rich source of pharmacological tools and drug leads. In a search for subtype-selective blockers of voltage-gated calcium (CaV) channels, we isolated and characterized a novel 39-residue peptide, ω-TRTX-Cc1a (Cc1a), from the venom of the tarantula Citharischius crawshayi (now Pelinobius muticus). Cc1a is 67% identical to the spider toxin ω-TRTX-Hg1a, an inhibitor of CaV2.3 channels. We assembled Cc1a using a combination of Boc solid-phase peptide synthesis and native chemical ligation. Oxidative folding yielded two stable, slowly interconverting isomers. Cc1a preferentially inhibited Ba(2+) currents (IBa) mediated by L-type (CaV1.2 and CaV1.3) CaV channels heterologously expressed in Xenopus oocytes, with half-maximal inhibitory concentration (IC50) values of 825nM and 2.24μM, respectively. In rat dorsal root ganglion neurons, Cc1a inhibited IBa mediated by high voltage-activated CaV channels but did not affect low voltage-activated T-type CaV channels. Cc1a exhibited weak activity at NaV1.5 and NaV1.7 voltage-gated sodium (NaV) channels stably expressed in mammalian HEK or CHO cells, respectively. Experiments with modified Cc1a peptides, truncated at the N-terminus (ΔG1-E5) or C-terminus (ΔW35-V39), demonstrated that the N- and C-termini are important for voltage-gated ion channel modulation. We conclude that Cc1a represents a novel pharmacological tool for probing the structure and function of L-type CaV channels. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Design and synthesis of collagen mimetic peptide derivatives for studying triple helix assembly and collagen mimetic peptide-collagen binding interaction

    Science.gov (United States)

    Mo, Xiao

    2008-10-01

    Collagen is the principal tensile clement of the extra-cellular matrix in mammals and is the basic scaffold for cells and tissues. Collagen molecules are comprised of homo-trimeric helices (e.g. collagen type II and type III), ABB type hetero-trimeric helices (e.g. collagen type I, type IV, and type V), or ABC type hetero-trimeric helices (e.g. type V). Mimicry of collagen structures can help elucidate collagen triple helical conformation and provide insights into making novel collagen-like biomaterials. Our group previously reported a new physical collagen modification method, which was based on non-covalent interaction between collagen mimetic peptide (CMP: -(Pro-Hyp-Gly) x-) and natural collagen. We hypothesized that CMP binds to collagen through a process involving both strand invasion and triple helix assembly. The aim of this dissertation is to study structural formation and stability of collagen triple helix, and to investigate CMP-collagen binding interactions using two types of CMP derivatives: covalently templated CMP trimer and CMP-nanoparticle conjugates. We demonstrated that covalently templated ABB type CMP hetero-trimers could be prepared by a versatile synthetic strategy involving both solid phase and solution peptide coupling. Our thermal melting studies showed that the templated CMP hetero-trimers formed collagen-like triple helices and their folding kinetics correlated with the amino acid compositions of the individual CMP strands. We also studied the thermal melting behavior and folding kinetics of a templated hetero-trimer complex comprised of CMP and a peptide derived from collagen. This synthetic strategy can be readily extended to synthesize other ABB type hetero-trimers to investigate their local melting behavior and biological activity. We also prepared colloidally stable CMP functionalized gold nanoparticles (Au-CMPs) as a TEM marker for investigating the CMP-collagen interaction. Au-CMP showed preferential binding to collagen fiber's gap

  19. Solid-phase synthesis of peptide thioureas and thiazole-containing macrocycles through ru-catalyzed ring-closing metathesis

    DEFF Research Database (Denmark)

    Cohrt, A. Emil; Nielsen, Thomas E.

    2014-01-01

    N-Terminally modified α-thiourea peptides can selectively be synthesized on solid support under mild reaction conditions using N,N′-di-Boc-thiourea and Mukaiyama's reagent (2-chloro-1-methyl-pyridinium iodide). This N-terminal modification applies to the 20 proteinogenic amino acid residues...

  20. Vasoactive intestinal polypeptide and peptide histidine methionine. Presence in human follicular fluid and effects on DNA synthesis and steroid secretion in cultured human granulosa/lutein cells

    DEFF Research Database (Denmark)

    Gräs, S; Ovesen, P; Andersen, A N

    1994-01-01

    Vasoactive intestinal polypeptide (VIP) and peptide histidine methionine (PHM) originate from the same precursor molecule, prepro VIP. In the present study we examined the concentrations of VIP and PHM in human follicular fluid and their effects on cultured human granulosa/lutein cells. Follicular...... fluid and cells were obtained from patients undergoing in-vitro fertilization for tubal infertility. The concentrations of VIP and PHM in pre-ovulatory human follicular fluid were measured radioimmunochemically. Granulosa/lutein cells isolated from follicular fluid were cultured under serum....... We conclude that VIP and PHM are present in human preovulatory follicular fluid and that VIP stimulates DNA synthesis and oestradiol secretion in cultured human granulosa/lutein cells. This indicates that VIP and perhaps PHM participate in the local nervous regulation of human ovarian function....

  1. Alcalase-catalysed synthesis of the precursor tetrapeptide N-benzoylarginylglycylaspartylserinamide (Bz-RGDS-NH2) of the cell-adhesion peptide arginylglycylaspartylserine (RGDS).

    Science.gov (United States)

    Huang, Yi-Bing; Yang, Sen; Cai, Yu; Wang, Hua; Gao, Gui; Wu, Xiao-Xia; Xu, Li; Zhang, Xue-Zhong

    2008-11-01

    In the present study, a precursor tetrapeptide Bz-RGDS-NH2 (N-benzoylarginylglycylaspartylserinamide) of cell-adhesion peptide RGDS (arginylglycylaspartylserine) was synthesized by a novel route. First of all, the precursor tripeptide GDS-NH2 (glycylaspartylserinamide) was synthesized by a chemical method only using aspartic acid and serine at gram scale in four steps. The linkage of the fourth amino acid Bz-Arg-OEt (N-benzoyl-L-arginine ethyl ester) to GDS-NH2 was completed by an enzymatic method under kinetic control in water-miscible organic media. An industrial alkaline protease, Alcalase, with a wide substrate specificity, was used as the catalyst. The effects of organic solvents, pH value, reaction temperature, water content and molar ratio of substrates on the yield of Bz-RGDS-NH2 synthesis were examined. The optimum reaction conditions were found to be pH 10.0, 35 degrees C, 8 h, in an acetonitrile/(Na2CO3/NaHCO3) buffer system (93:7, v/v) with a maximal yield of 65.2%. We found that secondary hydrolysis of the peptide product did not take place in these water-miscible organic solvents.

  2. Fmoc Solid-Phase Synthesis of Human a-Calcitonin Gene- Related Peptide and Two Carboxyfluorescein-labeled Analogs

    DEFF Research Database (Denmark)

    Ahmed, L. Sabbah; Abdolalizadeh, Bahareh; Sheykhzade, Majid

    Human-alpha-Calcitonin Gene-Related Peptide (h-alpha-CGRP) is a naturally occurring 37 amino acid vasodilatory neuropeptide amide, ACDTATCVTHRLAGLLSRSGGVVKNNFVPTNVGSKAF, with a disulfide bond between residues 2 and 7. The peptide is found in primary afferent sensory nerves and is widely distributed...... for biological activity and onset of signal transduction. Fluorescent h-alpha-CGRP analogs are useful for investigating the mechanism of action behind (re)uptake of h-alpha-CGRP into the sensory nerve terminals and monitoring trafficking of CGRP receptors. As part of an ongoing study on the mechanism of action......–17. Following purification by preparative HPLC, concentration-response curves were made with fluorescent CGRP analogues on isolated human subcutaneous arteries. CGRP (fluolysine35) and CGRP (wildtype) showed similar potency (pIC50 = 9.40) while CGRP (fluolysine24) showed approximately 5-fold less potency (pIC50...

  3. Synthesis and in vitro anti-cancer evaluation of luteinizing hormone-releasing hormone-conjugated peptide.

    Science.gov (United States)

    Deng, Xin; Qiu, Qianqian; Ma, Ke; Huang, Wenlong; Qian, Hai

    2015-11-01

    Luteinizing hormone-releasing hormone (LHRH) is a decapeptide hormone released from the hypothalamus and shows high affinity binding to the LHRH receptors. It is reported that several cancer cells also express LHRH receptors such as breast, ovarian, prostatic, bladder and others. In this study, we linked B1, an anti-cancer peptide, to LHRH and its analogs to improve the activity against cancer cells with LHRH receptor. Biological evaluation revealed that TB1, the peptide contains triptorelin sequence, present favorable anti-cancer activity as well as plasma stability. Further investigations disclosed that TB1 trigger apoptosis by activating the mitochondria-cytochrome c-caspase apoptotic pathway, it also exhibited the anti-migratory effect on cancer cells.

  4. Synthesis and labelling of organo-metallic prosthetic groups used for indirect radioiodination of peptides and proteins

    International Nuclear Information System (INIS)

    Pozzi, Oscar R.; Castiglia, Silvia G.

    1999-01-01

    In the framework of an IAEA co-ordinated research programme the prosthetic compound ATE [N-succidinimil 3-(tri-n-butylstannyl) benzoate] has been synthesized and it has been labelled with 131 I and 125 I. Its structure has been confirmed by NMR and mass spectrometry. The labelled ATE has been conjugated with human immunoglobulin G with a yield of 41%-57%. Indirect radioiodination of peptides is currently prepared. (author)

  5. Synthesis of Macrocyclic Organo-Peptide Hybrids from Ribosomal Polypeptide Precursors via CuAAC-/hydrazide-mediated cyclization

    OpenAIRE

    Smith, Jessica M.; Fasan, Rudi

    2015-01-01

    Macrocyclic peptides have attracted increasing attention as a potential new source of chemical probes and therapeutics. In particular, their conformationally restricted structure combined with a high degree of functional and stereochemical complexity make them promising scaffolds for targeting biomolecules with high affinity and selectivity. The exploration of this structural class rely on the availability of efficient and versatile methods for the generation of large and diversified librarie...

  6. Evaluation of acid-labile S-protecting groups to prevent Cys racemization in Fmoc solid-phase peptide synthesis

    OpenAIRE

    Hibino, Hajime; Miki, Yasuyoshi; Nishiuchi, Yuji

    2013-01-01

    Phosphonium and uronium salt-based reagents enable efficient and effective coupling reactions and are indispensable in peptide chemistry, especially in machine-assisted SPPS. However, after the activating and coupling steps with these reagents in the presence of tertiary amines, Fmoc derivatives of Cys are known to be considerably racemized during their incorporation. To avoid this side reaction, a coupling method mediated by phosphonium/uronium reagents with a weaker base, such as 2,4,6-trim...

  7. Synthesis and properties of peptide nucleic acid labeled at the N-terminus with HiLyte Fluor 488 fluorescent dye.

    Science.gov (United States)

    Hnedzko, Dziyana; McGee, Dennis W; Rozners, Eriks

    2016-09-15

    Fluorescently labeled peptide nucleic acids (PNAs) are important tools in fundamental research and biomedical applications. However, synthesis of labeled PNAs, especially using modern and expensive dyes, is less explored than similar preparations of oligonucleotide dye conjugates. Herein, we present a simple procedure for labeling of the PNA N-terminus with HiLyte Fluor 488 as the last step of solid phase PNA synthesis. A minimum excess of 1.25equiv of activated carboxylic acid achieved labeling yields close to 90% providing a good compromise between the price of dye and the yield of product and significant improvement over previous literature procedures. The HiLyte Fluor 488-labeled PNAs retained the RNA binding ability and in live cell fluorescence microscopy experiments were brighter and significantly more photostable than PNA labeled with carboxyfluorescein. In contrast to fluorescein-labeled PNA, the fluorescence of PNAs labeled with HiLyte Fluor 488 was independent of pH in the biologically relevant range of 5-8. The potential of HiLyte Fluor 488-labeling for studies of PNA cellular uptake and distribution was demonstrated in several cell lines. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Evaluation of new radiopharmaceuticals: synthesis, evaluation, and biodistribution of radiolabelled peptide of VCAM-1 and αvβ3

    International Nuclear Information System (INIS)

    Ardisson, V.

    2006-07-01

    The new development of nuclear medicine implies the search of new isotopes but also for new vectors specific of functions or metabolic pathways. We investigated new radiopharmaceuticals intended for new diagnostic approaches of two physiopathological mechanisms frequently met in our populations: the atherosclerosis vulnerable plaque and the tumor angio genesis. We studied and optimized the iodine and 99 m-technetium radiolabelling, of a series of peptides in order to allow the in vivo use of these tracers for imaging studies in animals and possibly in humans. The radioiodination, was carried out by electrophilic substitution, and technetium was linked by a tri-carbonyl B.F.C.A. (Isolink). The reaction parameters were defined so that the labelling reactions presents a high radiochemical purity (>95%), and a high specificity activity. The reactions are fast and reproducible. Various physicochemical properties: lipo-solubility, stability of labelling, and pharmacokinetic properties: non specific binding, metabolization and organ biodistribution of peptides in animal model, were studied. These results indicate which peptide may be a suitable candidate for targeting trials. (author)

  9. Design, synthesis and biological evaluation of novel peptide MC2 analogues from Momordica charantia as potential anti-diabetic agents.

    Science.gov (United States)

    Yang, Baowei; Li, Xue; Zhang, Chenyu; Yan, Sijia; Wei, Wei; Wang, Xuekun; Deng, Xin; Qian, Hai; Lin, Haiyan; Huang, Wenlong

    2015-04-21

    Three series of Momordica charantia (MC)2 analogues were designed, synthesized and evaluated for their anti-hyperglycaemic effects. Alanine scanning focusing on the peptide MC2 indicated the importance of the residues proline (Pro)(3), serine (Ser)(6), isoleucine (Ile)(7) and Ser(10) for anti-hyperglycaemic effects. Among the first series of MC2 analogues, peptide I-4 exhibited a better anti-hyperglycaemic effect and was chosen for further modification. A further two series of conformationally constrained analogues were designed by scanning the residues Pro(3), Ser(6), Ile(7), and Ser(10) with an i - (i + 2) lactam bridge consisting of a glutamic acid-Xaa-lysine (Glu-Xaa-Lys) scaffold and a diproline fragment. By screening in normal mice and mice with diabetes mellitus, peptides II-1, II-2 and III-3 showed a significant improvement in anti-hyperglycaemic and anti-oxidative activities compared with I-4. These data suggest that II-1, II-2 and III-3 could be candidates for future treatment of diabetes mellitus.

  10. [Synthesis of hybrid antimicrobial peptide CecA-mag gene and it's secretion expression in Pichia pastoris].

    Science.gov (United States)

    Wang, Xiu-qing; Su, Chun-xia; Zhou, Bin; Cao, Rui-bing; Chen, Pu-yan

    2007-02-01

    According to the partiality codon of Pichia pastoris, hybrid antimicrobial peptide CecA-mag gene was synthesized and cloned into pPICZa-A to construct the recombinant expression vector pPICZa-A-CA. The SacI-linearized plasmid pPICZalpha-A-CA was transformed into P. pastoris SMD1168 by electroporation. Under the control of the promoter AOX'(alcoholoxidase') , an approximately 1.9kDa cecA-mag protein was expressed. Antibacterial assays demonstrated that cecA-mag had broad spectrum of antimicrobial property against Gram-positive as well as Gram-negative bacteria especially showed potent antibacterial activity against ampicillin resistant bacteria, such as pathogenic E. coli. In addition, the hybrid antibacterial peptide showed an extreme heat stable and acid stable characteristic. These results suggest that the P. pastoris expression system can be used to produce large quantities of fully functional cecA-mag for both research and industrial purpose. Based on these characteristics, the recombinant antibacterial peptide cecA-mag displays application foreground in the field of prevention of disease, and can be used as additives of animal feedstuff and so on.

  11. Pyoverdine synthesis by the Mn(II-oxidizing bacterium Pseudomonas putida GB-1

    Directory of Open Access Journals (Sweden)

    Dorothy Lundquist Parker

    2014-05-01

    Full Text Available When iron-starved, the Mn(II-oxidizing bacteria Pseudomonas putida strains GB-1 and MnB1 produce pyoverdines (PVDGB-1 and PVDMnB1, siderophores that both influence iron uptake and inhibit manganese(II oxidation by these strains. To explore the properties and genetics of a PVD that can affect manganese oxidation, LC-MS/MS and various siderotyping techniques were used to identify the peptides of PVDGB-1 and PVDMnB1 as being (for both PVDs: chromophore-Asp-Lys-OHAsp-Ser-Gly-aThr-Lys-cOHOrn, resembling a structure previously reported for P. putida CFML 90-51, which does not oxidize Mn. All three strains also produced an azotobactin and a sulfonated PVD, each with the peptide sequence above, but with unknown regulatory or metabolic effects. Bioinformatic analysis of the sequenced genome of P. putida GB-1 suggested that a particular non-ribosomal peptide synthetase, coded by the operon PputGB1_4083-4086, could produce the peptide backbone of PVDGB-1. To verify this prediction, plasmid integration disruption of PputGB1_4083 was performed and the resulting mutant failed to produce detectable PVD. In silico analysis of the modules in PputGB1_4083-4086 predicted a peptide sequence of Asp-Lys-Asp-Ser-Ala-Thr-Lsy-Orn, which closely matches the peptide determined by MS/MS. To extend these studies to other organisms, various Mn(II-oxidizing and non-oxidizing isolates of P. putida, P. fluorescens, P. marincola, P. fluorescens-syringae group, P. mendocina-resinovorans group and P. stutzerii group were screened for PVD synthesis. The PVD producers (12 out of 16 tested strains were siderotyped and placed into four sets of differing PVD structures, some corresponding to previously characterized PVDs and some to novel PVDs. These results combined with previous studies suggested that the presence of OHAsp or the flexibility of the pyoverdine polypeptide may enable efficient binding of Mn(III.

  12. Pyoverdine synthesis by the Mn(II)-oxidizing bacterium Pseudomonas putida GB-1

    Science.gov (United States)

    Parker, Dorothy L.; Lee, Sung-Woo; Geszvain, Kati; Davis, Richard E.; Gruffaz, Christelle; Meyer, Jean-Marie; Torpey, Justin W.; Tebo, Bradley M.

    2014-01-01

    When iron-starved, the Mn(II)-oxidizing bacteria Pseudomonas putida strains GB-1 and MnB1 produce pyoverdines (PVDGB-1 and PVDMnB1), siderophores that both influence iron uptake and inhibit manganese(II) oxidation by these strains. To explore the properties and genetics of a PVD that can affect manganese oxidation, LC-MS/MS, and various siderotyping techniques were used to identify the peptides of PVDGB-1 and PVDMnB1 as being (for both PVDs): chromophore-Asp-Lys-OHAsp-Ser-Gly-aThr-Lys-cOHOrn, resembling a structure previously reported for P. putida CFML 90-51, which does not oxidize Mn. All three strains also produced an azotobactin and a sulfonated PVD, each with the peptide sequence above, but with unknown regulatory or metabolic effects. Bioinformatic analysis of the sequenced genome of P. putida GB-1 suggested that a particular non-ribosomal peptide synthetase (NRPS), coded by the operon PputGB1_4083-4086, could produce the peptide backbone of PVDGB-1. To verify this prediction, plasmid integration disruption of PputGB1_4083 was performed and the resulting mutant failed to produce detectable PVD. In silico analysis of the modules in PputGB1_4083-4086 predicted a peptide sequence of Asp-Lys-Asp-Ser-Ala-Thr-Lsy-Orn, which closely matches the peptide determined by MS/MS. To extend these studies to other organisms, various Mn(II)-oxidizing and non-oxidizing isolates of P. putida, P. fluorescens, P. marincola, P. fluorescens-syringae group, P. mendocina-resinovorans group, and P. stutzerii group were screened for PVD synthesis. The PVD producers (12 out of 16 tested strains) were siderotyped and placed into four sets of differing PVD structures, some corresponding to previously characterized PVDs and some to novel PVDs. These results combined with previous studies suggested that the presence of OHAsp or the flexibility of the pyoverdine polypeptide may enable efficient binding of Mn(III). PMID:24847318

  13. One Hundred Years of Peptide Chemistry

    Indian Academy of Sciences (India)

    ber of residues are often denoted as peptides. The chemical synthesis of peptides, as envisaged by Fischer, involves ... known as genetically encoded as building blocks of peptides and proteins. Almost all of .... inhibit final stages of the enzymatic construction of the bacterial peptidoglycan cell wall component, a network of.

  14. Evaluation of acid-labile S-protecting groups to prevent Cys racemization in Fmoc solid-phase peptide synthesis.

    Science.gov (United States)

    Hibino, Hajime; Miki, Yasuyoshi; Nishiuchi, Yuji

    2014-01-01

    Phosphonium and uronium salt-based reagents enable efficient and effective coupling reactions and are indispensable in peptide chemistry, especially in machine-assisted SPPS. However, after the activating and coupling steps with these reagents in the presence of tertiary amines, Fmoc derivatives of Cys are known to be considerably racemized during their incorporation. To avoid this side reaction, a coupling method mediated by phosphonium/uronium reagents with a weaker base, such as 2,4,6-trimethylpyridine, than the ordinarily used DIEA or that by carbodiimide has been recommended. However, these methods are appreciably inferior to the standard protocol applied for SPPS, that is, a 1 min preactivation procedure of coupling with phosphonium or uronium reagents/DIEA in DMF, in terms of coupling efficiency, and also the former method cannot reduce racemization of Cys(Trt) to an acceptable level (DIEA in DMF. Furthermore, these protecting groups significantly reduced the rate of racemization compared to the Trt group even in the case of microwave-assisted SPPS performed at a high temperature. © 2013 The Authors. European Peptide Society published by John Wiley & Sons, Ltd.

  15. In vivo synthesis of cholecystokinin in the rat cerebral cortex: identification of COOH-terminal peptides with labeled amino acids

    International Nuclear Information System (INIS)

    Goltermann, N.R.

    1982-01-01

    The synthesis of the COOH-terminal octa- and tetrapeptides of cholecystokinin (CCK) has been studied in rat cerebral cortex after intraventricular administration of radioactive amino acids characteristic of the porcine COOH-terminal octapeptide of CCK, CCK-8. After immunosorption with a COOH-terminal directed antibody, cortical CCK was fractionated on Sephadex G-50 columns. The experiments demonstrated newly synthesized CCK forms which coeluted with porcine CCK-8 and CCK-4. Except for threonine the amino acids employed, methionine, tryptophan, aspartic acid, glycine and phenylalanine were incorporated. The sequence-specific radioimmunoassay, the incorporation of the employed labeled amino acids, and the elution pattern by gel filtration, suggest an almost identical structure of porcine and rat cortical CCK-8, and a concomitant synthesis of CCK-8 and CCK-4 in rat cerebral cortex

  16. A Hybrid Non-Ribosomal Peptide/Polyketide Synthetase Containing Fatty-Acyl Ligase (FAAL) Synthesizes the beta-Amino Fatty Acid Lipopeptides Puwainaphycins in the Cyanobacterium Cylindrospermum alatosporum

    Czech Academy of Sciences Publication Activity Database

    Mareš, J.; Hájek, J.; Urajová, Petra; Kopecký, Jiří; Hrouzek, Pavel

    2014-01-01

    Roč. 9, č. 11 (2014) E-ISSN 1932-6203 R&D Projects: GA MŠk ED2.1.00/03.0110; GA ČR GA14-18067S Institutional support: RVO:61388971 Keywords : blue green alga * FAAL * Cylindrospermum alatosporum Subject RIV: CE - Biochemistry Impact factor: 3.234, year: 2014

  17. A hybrid non-ribosomal peptide/polyketide synthetase containing fatty-acyl ligase (FAAL) synthesizes the β-amino fatty acid lipopeptides puwainaphycins in the cyanobacterium Cylindrospermum alatosporum

    Czech Academy of Sciences Publication Activity Database

    Mareš, Jan; Hájek, Jan; Urajová, P.; Kopecký, J.; Hrouzek, P.

    2014-01-01

    Roč. 9, č. 11 (2014), e111904 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA14-18067S Institutional support: RVO:60077344 Keywords : cyanobacteria * lipopeptides * biosynthesis Subject RIV: CE - Biochemistry Impact factor: 3.234, year: 2014

  18. Leiurotoxin I (scyllatoxin), a peptide ligand for Ca2(+)-activated K+ channels. Chemical synthesis, radiolabeling, and receptor characterization

    Energy Technology Data Exchange (ETDEWEB)

    Auguste, P.; Hugues, M.; Grave, B.; Gesquiere, J.C.; Maes, P.; Tartar, A.; Romey, G.; Schweitz, H.; Lazdunski, M. (Institut de Pharmacologie du Centre National de la Recherche Scientifique, Valbonne (France))

    1990-03-15

    Leiurotoxin I (scyllatoxin) is a 31-amino acid polypeptide from the venom of the scorpion Leiurus quinquestriatus hebraeus which has been previously isolated and sequenced by others. This paper reports (i) the total synthesis of this scorpion neurotoxin as well as some aspects of its structure-function relationships; (ii) the synthesis of the analog (Tyr2)leiurotoxin I (scyllatoxin) that has been monoiodinated at high specific radioactivity (2000 Ci/mmol) and has served for the characterization of the properties of {sup 125}I-(Tyr2)leiurotoxin I binding sites (Kd = 80 pM, molecular mass of 27 and 57 kDa for two polypeptides in the leiurotoxin I binding protein); (iii) the similarity of physiological actions between leiurotoxin I and apamin. Both toxins contract Taenia coli previously relaxed with epinephrine, both toxins block the after-hyperpolarization due to Ca2(+)-activated K+ channel activity in muscle cells in culture; (iv) the probable identity of binding sites for apamin and leiurotoxin I. In spite of a different chemical structure apamin competitively inhibits {sup 125}I-(Tyr2) leiurotoxin I binding and vice versa. Moreover, the peculiar effects of K+ on {sup 125}I-(Tyr2)leiurotoxin I binding are identical to those previously observed for {sup 125}I-apamin binding.

  19. Design and synthesis of 4'-((5-benzylidene-2,4-dioxothiazolidin-3-yl)methyl)biphenyl-2-carbonitrile analogs as bacterial peptide deformylase inhibitors.

    Science.gov (United States)

    Khan, Firoz A Kalam; Patil, Rajendra H; Shinde, Devanand B; Sangshetti, Jaiprakash N

    2016-12-01

    Herein, we report the synthesis and screening of 4'-((5-benzylidene-2,4-dioxothiazolidin-3-yl)methyl)biphenyl-2-carbonitrile analogs 11(a-j) as bacterial peptide deformylase (PDF) enzyme inhibitors. The compounds 11b (IC 50 value = 139.28 μm), 11g (IC 50 value = 136.18 μm), and 11h (IC 50 value = 131.65 μm) had shown good PDF inhibition activity. The compounds 11b (MIC range = 103.36-167.26 μg/mL), 11g (MIC range = 93.75-145.67 μg/mL), and 11h (MIC range = 63.61-126.63 μg/mL) had also shown potent antibacterial activity when compared with standard ampicillin (MIC range = 100.00-250.00 μg/mL). Thus, the active derivatives were not only PDF inhibitors but also efficient antibacterial agents. To gain more insight on the binding mode of the compounds with PDF enzyme, the synthesized compounds 11(a-j) were docked against PDF enzyme of Escherichia coli and compounds exhibited good binding properties. The results suggest that this class of compounds has potential for development and use in future as antibacterial drugs. © 2016 John Wiley & Sons A/S.

  20. Bacterial Peptide deformylase inhibition of cyano substituted biaryl analogs: Synthesis, in vitro biological evaluation, molecular docking study and in silico ADME prediction.

    Science.gov (United States)

    Khan, Firoz A Kalam; Patil, Rajendra H; Shinde, Devanand B; Sangshetti, Jaiprakash N

    2016-08-15

    Herein, we report the synthesis and screening of cyano substituted biaryl analogs 5(a-m) as Peptide deformylase (PDF) enzyme inhibitors. The compounds 5a (IC50 value=13.16μM), 5d (IC50 value=15.66μM) and 5j (IC50 value=19.16μM) had shown good PDF inhibition activity. The compounds 5a (MIC range=11.00-15.83μg/mL), 5b (MIC range=23.75-28.50μg/mL) and 5j (MIC range=7.66-16.91μg/mL) had also shown potent antibacterial activity when compared with ciprofloxacin (MIC range=25-50μg/mL). Thus, the active derivatives were not only potent PDF inhibitors but also efficient antibacterial agents. In order to gain more insight on the binding mode of the compounds with PDF, the synthesized compounds 5(a-m) were docked against PDF enzyme of Escherichia coli and compounds exhibited good binding properties. In silico ADME properties of synthesized compounds were also analyzed and showed potential to develop as good oral drug candidates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. The on-line synthesis of enzyme functionalized silica nanoparticles in a microfluidic reactor using polyethylenimine polymer and R5 peptide

    International Nuclear Information System (INIS)

    He Ping; Greenway, Gillian; Haswell, Stephen J

    2008-01-01

    A simple microfluidic reactor system is described for the effective synthesis of enzyme functionalized nanoparticles which offers many advantages over batch reactions, including excellent enzyme efficiencies. Better control of the process parameters in the microfluidic reactor system over batch based methodology enables the production of silica nanoparticles with the optimum size for efficient enzyme immobilization with long-term stability. The synthetic approach is demonstrated with glucose oxidase (GOD) and two different nucleation catalysts of similar molecular mass: the natural R5 peptide, and polyethylenimine (PEI) polymer. Near-quantitative immobilization of GOD in the nanoparticles is obtained using PEI; the immobilization is attributed to electrostatic interaction between PEI and GOD. This interaction, however, limits the mobility of the immobilized enzyme, producing orientation hindrance of the enzyme's active sites as compared to free GOD in solution. In contrast, when the GOD is immobilized inside the silica nanoparticles using R5, lower enzyme immobilization efficiencies are obtained compared to using PEI polymers; however, similar Michaelis-Menten kinetic parameters (i.e. Michaelis constant and turnover number) to those of free GOD are observed. Reactions were monitored in situ using simple, rapid, separation-free amperometric detection

  2. Antibody Production with Synthetic Peptides.

    Science.gov (United States)

    Lee, Bao-Shiang; Huang, Jin-Sheng; Jayathilaka, Lasanthi P; Lee, Jenny; Gupta, Shalini

    2016-01-01

    Peptides (usually 10-20 amino acid residues in length) can be used as effectively as proteins in raising antibodies producing both polyclonal and monoclonal antibodies routinely with titers higher than 20,000. Peptide antigens do not function as immunogens unless they are conjugated to proteins. Production of high quality antipeptide antibodies is dependent upon peptide sequence selection, the success of peptide synthesis, peptide-carrier protein conjugation, the humoral immune response in the host animal, the adjuvant used, the peptide dose administered, the injection method, and the purification of the antibody. Peptide sequence selection is probably the most critical step in the production of antipeptide antibodies. Although the process for designing peptide antigens is not exact, several guidelines and computational B-cell epitope prediction methods can help maximize the likelihood of producing antipeptide antibodies that recognize the protein. Antibodies raised by peptides have become essential tools in life science research. Virtually all phospho-specific antibodies are now produced using phosphopeptides as antigens. Typically, 5-20 mg of peptide is enough for antipeptide antibody production. It takes 3 months to produce a polyclonal antipeptide antibody in rabbits that yields ~100 mL of serum which corresponds to ~8-10 mg of the specific antibody after affinity purification using a peptide column.

  3. Peptide dendrimer-conjugates of ketoprofen: Synthesis and ex vivo and in vivo evaluations of passive diffusion, sonophoresis and iontophoresis for skin delivery.

    Science.gov (United States)

    Hegde, Aswathi R; Rewatkar, Prarthana V; Manikkath, Jyothsna; Tupally, Karnaker; Parekh, Harendra S; Mutalik, Srinivas

    2017-05-01

    The aim of this study was to evaluate skin delivery of ketoprofen when covalently tethered to mildly cationic (2 + or 4 + ) peptide dendrimers prepared wholly by solid phase peptide synthesis. The amino acids glycine, arginine and lysine formed the dendrimer with ketoprofen tethered either to the lysine side-arm (N ε ) or periphery of dendrimeric branches. Passive diffusion, sonophoresis- and iontophoresis-assisted permeation of each peptide dendrimer-drug conjugate (D1-D4) was studied across mouse skin, both in vitro and in vivo. In addition, skin toxicity of dendrimeric conjugates when trialed with iontophoresis or sonophoresis was also evaluated. All dendrimeric conjugates improved aqueous solubility at least 5-fold, compared to ketoprofen alone, while also exhibiting appreciable lipophilicity. In vitro passive diffusion studies revealed that ketoprofen in its native form was delivered to a greater extent, compared with a dendrimer-conjugated form at the end of 24h (Q 24h (μg/cm 2 ): ketoprofen (68.06±3.62)>D2 (49.62±2.92)>D4 (19.20±0.89)>D1 (6.45±0.40)>D3 (2.21±0.19). However, sonophoresis substantially increased the skin permeation of ketoprofen-dendrimer conjugates in 30min (Q 30min (μg/cm 2 ): D4 (122.19±7.14)>D2 (66.74±3.86)>D1 (52.10±3.22)>D3 (41.66±3.22)) although ketoprofen alone again proved superior (Q 30min : 167.99±9.11μg/cm 2 ). Next, application of iontophoresis was trialed and shown to considerably increase permeation of dendrimeric ketoprofen in 6h (Q 6h (μg/cm 2 ): D2 (711.49±39.14)>D4 (341.23±16.43)>D3 (89.50±4.99)>D1 (50.91±2.98), with a Q 6h value of 96.60±5.12μg/cm 2 for ketoprofen alone). In vivo studies indicated that therapeutically relevant concentrations of ketoprofen could be delivered transdermally when iontophoresis was paired with D2 (985.49±43.25ng/mL). Further, histopathological analysis showed that the dendrimeric approach was a safe mode as ketoprofen alone. The present study successfully demonstrates that

  4. Endogenous cross-talk of fungal metabolites.

    Directory of Open Access Journals (Sweden)

    Kevin J Sheridan

    2015-01-01

    Full Text Available Non-ribosomal peptide synthesis in fungi requires a ready supply of proteogenic and non-proteogenic amino acids which are subsequently incorporated into the nascent non-ribosomal peptide via a thiotemplate mechanism catalysed by non-ribosomal peptide synthetases. Substrate amino acids can be modified prior to or during incorporation into the non-ribosomal peptide, or following incorporation into an early stage amino acid-containing biosynthetic intermediate. These post-incorporation modifications involve a range of additional enzymatic activities including but not exclusively, monooxygenases, methyltransferases, epimerases, oxidoreductases and glutathione transferases which are essential to effect biosynthesis of the final non-ribosomal peptide. Likewise, polyketide biosynthesis is directly by polyketide synthase megaenzymes and cluster-encoded ancilliary decorating enzymes. Additionally, a suite of additional primary metabolites, for example: CoA, acetyl CoA, S-adenosylmethionine, glutathione, NADPH, malonyl CoA and molecular oxygen, amongst others are required for non-ribosomal peptide and polyketide synthesis. Clearly these processes must involve exquisite orchestration to facilitate the simultaneous biosynthesis of different types of non-ribosomal peptides, polyketides, and related metabolites requiring identical or similar biosynthetic precursors or co-factors. Moreover, the near identical structures of many natural products within a given family (e.g., ergot alkaloids, along with localization to similar regions within fungi (e.g., conidia suggests that cross-talk may exist, in terms of biosynthesis and functionality. Finally, we speculate if certain biosynthetic steps involved in non-ribosomal peptide and polyketide synthesis play a role in cellular protection or environmental adaptation, and wonder if these enzymatic reactions are of equivalent importance to the actual biosynthesis of the final metabolite.

  5. Synthetic peptide inhibitors of DNA replication in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Løbner-Olesen, Anders; Kjelstrup, Susanne

    F counterselection was developed to directly select for compounds able to disrupt selected interactions. We have subsequently constructed a cyclic peptide library for intracellular synthesis of cyclic peptides using known technology. Several cyclic peptides were able to interfere with oligomerization of Dna......N (), DnaB and DnaX (). Three peptides identified as inhibitors of DnaN have been purified. Two of these peptides inhibited growth as well as DNA replication in S. aureus. The minimal inhibitory concentration (MIC) of the peptides was approximately 50 g/ml. Overexpression of DnaN reduced the inhibitory...... effect of the peptides confirming the target of the peptides....

  6. Novel peptide-based protease inhibitors

    DEFF Research Database (Denmark)

    Roodbeen, Renée

    This thesis describes the design and synthesis of peptide-based serine protease inhibitors. The targeted protease, urokinase-type plasminogen activator (uPA) activates plasminogen, which plays a major role in cancer metastasis. The peptide upain-2 (S 1 ,S 12-cyclo-AcCSWRGLENHAAC-NH2) is a highly...... of novel peptide-based protease inhibitors, efforts were made towards improved methods for peptide synthesis. The coupling of Fmoc-amino acids onto N-methylated peptidyl resins was investigated. These couplings can be low yielding and the effect of the use of microwave heating combined with the coupling...

  7. Peptide dendrimers

    Czech Academy of Sciences Publication Activity Database

    Niederhafner, Petr; Šebestík, Jaroslav; Ježek, Jan

    2005-01-01

    Roč. 11, - (2005), 757-788 ISSN 1075-2617 R&D Projects: GA ČR(CZ) GA203/03/1362 Institutional research plan: CEZ:AV0Z40550506 Keywords : multiple antigen peptides * peptide dendrimers * synthetic vaccine * multipleantigenic peptides Subject RIV: CC - Organic Chemistry Impact factor: 1.803, year: 2005

  8. Synthesis of dispersive iron or iron–silver nanoparticles on engineered capsid pVIII of M13 virus with electronegative terminal peptides

    International Nuclear Information System (INIS)

    Zhang, Shuai; Nakano, Kazuhiko; Zhang, Shu-liang; Yu, Hui-min

    2015-01-01

    M13 is a filamentous Escherichia coli virus covered with five types of capsid proteins, in which pVIII with ∼2700 copies was around the cylindered surface and pIII with five copies located at one end of the phage particle. The pIII-engineered M13 phages with enhanced binding specificity toward Fe were screened after five rounds of biopanning, and the one containing ATPTVAMSLSPL peptide at pIII-terminus was selected for mediated synthesis of zero valent (ZV) Fe nanoparticles (NPs) with the wild M13 as control. Under a reducing environment, uniformly dispersed ZVFeNPs with diameter of 5–10 nm were both synthesized and the morphologies after annealing were confirmed to be face-centered cubic type. The synthesized FeNPs mediated by the two phages showed no significant difference, revealing that the pVIII capsid did dominant contribution to metal binding in comparison with the pIII. A novel pVIII-engineered M13 containing AAEEEDPAK at terminus, named as 4ED-pVIII-M13, was constructed and it carried one more negatively charged residue than the wild one (AEGDDPAK). Metal adsorption quantification showed that the binding affinity of the 4ED-pVIII-M13 toward Ag and Ni ions improved to 62 and 18 % from original 21 and 6 %, respectively. The binding affinity toward Fe remained constant (∼85 %). ZVFe–Ag bi-NPs were successfully synthesized through mediation of 4ED-pVIII-M13. Particularly, the Fe:Ag ratio in the bi-NPs was conveniently controlled through changing the molar concentration of FeCl 2 and AgNO 3 solution before reduction

  9. Bacterial expression and/or solid phase peptide synthesis of 20-40 amino acid long polypeptides and miniproteins, the case study of Class B GPCR ligands.

    Science.gov (United States)

    Stráner, Pál; Taricska, Nóra; Szabó, Mária; Tóth, Gábor K; Perczel, András

    2016-01-01

    By using two different synthetic techniques several polypeptides interacting with Class B type G-protein coupled receptors were prepared. These polypeptides of different lengths (20 ≤ amino acids ≤ 40), structural and aggregation properties, were prepared both by solid phase peptide synthesis (SPPS) and E.coli bacterial expression. Their purity, synthetic yields, by-products and (15)N/(13)Clabelling characteristics were compared as function of i) the applied method, ii) amino acid length and iii) folding propensities. Their tentative yields, costs and "environmental footprints" were analyzed and found as follows. For unlabelled and short polypeptides (n= 20 aa.) the method of choice is the less environmentally friendly however, quick and effective SPPS. If the polypeptide is (un)folded and/or has no aggregation propensity, then SPPS gives relatively good yield (e.g. 14 ± 4%) and a pure product (>97%). For aggregating polypeptides production yields drop for both methods 4 ± 2% (SPPS) and 2 ± 1% (E. coli), respectively. For longer (n≥ 30 aa.) macromolecules (e.g. miniproteins) bacterial expression efficacy gets higher. Moreover biotechnology is "greener", the resulting in raw material is purer (2.8 ± 1.5 mg). All these advantages for at a lower cost: ~4 €/aa. If isotopic labelling is needed for heteronuclear NMR measurements, bacterial expression is the sole option, due to the high cost of (15)N/(13)C labelled Fmoc(Boc)-L-aa-OH starting materials needed for SPPS. In E.coli uniformly double-labelled, pure polypeptides can be obtained for less than 5-700 €/mg, regardless of the length of the polypeptide chain. Thus, chemists are encouraged to use E.coli expression systems when adequate to make not only proteins but polypeptides and miniproteins as well.

  10. Synthesis of dispersive iron or iron-silver nanoparticles on engineered capsid pVIII of M13 virus with electronegative terminal peptides

    Science.gov (United States)

    Zhang, Shuai; Nakano, Kazuhiko; Zhang, Shu-liang; Yu, Hui-min

    2015-10-01

    M13 is a filamentous Escherichia coli virus covered with five types of capsid proteins, in which pVIII with 2700 copies was around the cylindered surface and pIII with five copies located at one end of the phage particle. The pIII-engineered M13 phages with enhanced binding specificity toward Fe were screened after five rounds of biopanning, and the one containing ATPTVAMSLSPL peptide at pIII-terminus was selected for mediated synthesis of zero valent (ZV) Fe nanoparticles (NPs) with the wild M13 as control. Under a reducing environment, uniformly dispersed ZVFeNPs with diameter of 5-10 nm were both synthesized and the morphologies after annealing were confirmed to be face-centered cubic type. The synthesized FeNPs mediated by the two phages showed no significant difference, revealing that the pVIII capsid did dominant contribution to metal binding in comparison with the pIII. A novel pVIII-engineered M13 containing AAEEEDPAK at terminus, named as 4ED-pVIII-M13, was constructed and it carried one more negatively charged residue than the wild one (AEGDDPAK). Metal adsorption quantification showed that the binding affinity of the 4ED-pVIII-M13 toward Ag and Ni ions improved to 62 and 18 % from original 21 and 6 %, respectively. The binding affinity toward Fe remained constant ( 85 %). ZVFe-Ag bi-NPs were successfully synthesized through mediation of 4ED-pVIII-M13. Particularly, the Fe:Ag ratio in the bi-NPs was conveniently controlled through changing the molar concentration of FeCl2 and AgNO3 solution before reduction.

  11. Synthesis of dispersive iron or iron–silver nanoparticles on engineered capsid pVIII of M13 virus with electronegative terminal peptides

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuai; Nakano, Kazuhiko; Zhang, Shu-liang; Yu, Hui-min, E-mail: yuhm@tsinghua.edu.cn [Tsinghua University, Key Laboratory of Industrial Biocatalysis of the Ministry of Education, Department of Chemical Engineering (China)

    2015-10-15

    M13 is a filamentous Escherichia coli virus covered with five types of capsid proteins, in which pVIII with ∼2700 copies was around the cylindered surface and pIII with five copies located at one end of the phage particle. The pIII-engineered M13 phages with enhanced binding specificity toward Fe were screened after five rounds of biopanning, and the one containing ATPTVAMSLSPL peptide at pIII-terminus was selected for mediated synthesis of zero valent (ZV) Fe nanoparticles (NPs) with the wild M13 as control. Under a reducing environment, uniformly dispersed ZVFeNPs with diameter of 5–10 nm were both synthesized and the morphologies after annealing were confirmed to be face-centered cubic type. The synthesized FeNPs mediated by the two phages showed no significant difference, revealing that the pVIII capsid did dominant contribution to metal binding in comparison with the pIII. A novel pVIII-engineered M13 containing AAEEEDPAK at terminus, named as 4ED-pVIII-M13, was constructed and it carried one more negatively charged residue than the wild one (AEGDDPAK). Metal adsorption quantification showed that the binding affinity of the 4ED-pVIII-M13 toward Ag and Ni ions improved to 62 and 18 % from original 21 and 6 %, respectively. The binding affinity toward Fe remained constant (∼85 %). ZVFe–Ag bi-NPs were successfully synthesized through mediation of 4ED-pVIII-M13. Particularly, the Fe:Ag ratio in the bi-NPs was conveniently controlled through changing the molar concentration of FeCl{sub 2} and AgNO{sub 3} solution before reduction.

  12. The Pharmacological Potential of Nonribosomal Peptides from Marine Sponge and Tunicates

    Directory of Open Access Journals (Sweden)

    Shivankar Agrawal

    2016-10-01

    Full Text Available Marine biodiversity is recognized by a wide and unique array of fascinating structures. The complex associations of marine microorganisms, especially with sponges, bryozoans, and tunicates, make it extremely difficult to define the biosynthetic source of marine natural products or to deduce their ecological significance. Marine sponges and tunicates are important source of novel compounds for drug discovery and development. Majority of these compounds are nitrogen containing and belong to non-ribosomal peptide (NRPs or mixed polyketide–NRP natural products. Several of these peptides are currently under trial for developing new drugs against various disease areas, including inflammatory, cancer, neurodegenerative disorders and infectious disease. This review features pharmacologically active NRPs from marine sponge and tunicates based on their biological activities.

  13. Design, Synthesis and Evaluation of Branched RRWQWR-Based Peptides as Antibacterial Agents Against Clinically Relevant Gram-Positive and Gram-Negative Pathogens

    Directory of Open Access Journals (Sweden)

    Sandra C. Vega

    2018-03-01

    Full Text Available Multidrug resistance of pathogenic bacteria has become a public health crisis that requires the urgent design of new antibacterial drugs such as antimicrobial peptides (AMPs. Seeking to obtain new, lactoferricin B (LfcinB-based synthetic peptides as viable early-stage candidates for future development as AMPs against clinically relevant bacteria, we designed, synthesized and screened three new cationic peptides derived from bovine LfcinB. These peptides contain at least one RRWQWR motif and differ by the copy number (monomeric, dimeric or tetrameric and structure (linear or branched of this motif. They comprise a linear palindromic peptide (RWQWRWQWR, a dimeric peptide (RRWQWR2KAhx and a tetrameric peptide (RRWQWR4K2Ahx2C2. They were screened for antibacterial activity against Enterococcus faecalis (ATCC 29212 and ATCC 51575 strains, Pseudomonas aeruginosa (ATCC 10145 and ATCC 27853 strains and clinical isolates of two Gram-positive bacteria (Enterococcus faecium and Staphylococcus aureus and two Gram-negative bacteria (Klebsiella pneumoniae and Pseudomonas aeruginosa. All three peptides exhibited greater activity than did the reference peptide, LfcinB (17–31, which contains a single linear RRWQWR motif. Against the ATCC reference strains, the three new peptides exhibited minimum inhibitory concentration (MIC50 values of 3.1–198.0 μM and minimum bactericidal concentration (MBC values of 25–200 μM, and against the clinical isolates, MIC50 values of 1.6–75.0 μM and MBC values of 12.5–100 μM. However, the tetrameric peptide was also found to be strongly hemolytic (49.1% at 100 μM. Scanning Electron Microscopy (SEM demonstrated that in the dimeric and tetrameric peptides, the RRWQWR motif is exposed to the pathogen surface. Our results may inform the design of new, RRWQWR-based AMPs.

  14. Implication of C-type natriuretic peptide-3 signaling in glycosaminoglycan synthesis and chondrocyte hypertrophy during TGF-β1 induced chondrogenic differentiation of chicken bone marrow-derived mesenchymal stem cells.

    Science.gov (United States)

    Kocamaz, Erdogan; Gok, Duygu; Cetinkaya, Ayse; Tufan, A Cevik

    2012-10-01

    This study investigated the involvement of CNP-3, chick homologue for human C-type natriuretic peptide (CNP), in TGF-β1 induced chondrogenic differentiation of chicken bone marrow-derived mesenchymal stem cells (MSCs). Chondrogenic differentiation of MSCs in pellet cultures was induced by TGF-β1. Chondrogenic differentiation and glycosaminoglycan synthesis were analyzed on the basis of basic histology, collagen type II expression, and Alcian blue staining. Antibodies against CNP and NPR-B were used to block their function during these processes. Results revealed that expression of CNP-3 and NPR-B in MSCs were regulated by TGF-β1 in monolayer cultures at mRNA level. In pellet cultures of MSCs, TGF-β1 successfully induced chondrogenic differentiation and glycosaminoglycan synthesis. Addition of CNP into the TGF-β1 supplemented chondrogenic differentiation medium further induced the glycosaminoglycan synthesis and hypertrophy of differentiated chondrocytes in these pellets. Pellets induced with TGF-β1 and treated with antibodies against CNP and NPR-B, did show collagen type II expression, however, Alcian blue staining showing glycosaminoglycan synthesis was significantly suppressed. In conclusion, CNP-3/NPR-B signaling may strongly be involved in synthesis of glycosaminoglycans of the chondrogenic matrix and hypertrophy of differentiated chondrocytes during TGF-β1 induced chondrogenic differentiation of MSCs.

  15. Preparation of polypeptides comprising multiple TAA peptides.

    Science.gov (United States)

    Ni, Bing; Jia, Zhengcai; Wu, Yuzhang

    2014-01-01

    Polypeptides consisting of multiple tumor-associated antigen epitopes (multiepitope peptides) are commonly used as therapeutic peptide cancer vaccines in experimental studies and clinical trials. These methods include polypeptides composed of multiple major histocompatibility complex (MHC) class I-restricted cytotoxic T cell (CTL) epitopes and those containing multiple CTL epitopes and one T helper (Th) epitope. This chapter describes a complete set of methods for preparing multiepitope peptides and branched multiple antigen peptides (MAPs), including sequence design, peptide synthesis, purification, preservation, and the preparation of polypeptide solutions.

  16. Nunamycin and Nunapeptin: Two novel cyclic peptides are key components of the antimicrobial activity of the Greenlandic isolate Pseudomonas fluorescens In5

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Phippen, Christopher; Nielsen, Kristian F.

    Pseudomonas spp. are a rich source of secondary metabolites including bioactive non-ribosomal peptides (NRPs) and polyketides. NRPs are synthesised in large assembly lines by multi-domain modular enzymes known as NRP-synthetases (NRPS). Nunamycin and nunapeptin are two cyclic NRPs synthesised...... by the Greenlandic isolate P. fluorescens In5. Nunamycin shows antifungal activity against the basidiomycete Rhizoctonia solani whereas the only partially structure elucidated nunapeptin appears most active against the ascomycete Fusarium graminearum and the oomycete Pythium aphanidermatum. Originally isolated from...

  17. Synthesis and Evaluation of a Series of Long-Acting Glucagon-Like Peptide-1 (GLP-1) Pentasaccharide Conjugates for the Treatment of Type 2 Diabetes.

    Science.gov (United States)

    Irwin, Nigel; Patterson, Steven; de Kort, Martin; Moffett, R Charlotte; Wisse, Jeffry A J; Dokter, Wim H A; Bos, Ebo S; Miltenburg, André M M; Flatt, Peter R

    2015-08-01

    The present study details the development of a family of novel D-Ala(8) glucagon-like peptide-1 (GLP-1) peptide conjugates by site specific conjugation to an antithrombin III (ATIII) binding carrier pentasaccharide through tetraethylene glycol linkers. All conjugates were found to possess potent insulin-releasing activity. Peptides with short linkers (GLP-1 receptor (GLP-1-R) binding affinity. All D-Ala(8) GLP-1 conjugates exhibited prominent glucose-lowering action. Biological activity of the Lys(37) short-linker peptide was evident up to 72 h post-injection. In agreement, the pharmacokinetic profile of this conjugate (t1/2 , 11 h) was superior to that of the GLP-1-R agonist, exenatide. Once-daily injection of the Lys(37) short-linker peptide in ob/ob mice for 21 days significantly decreased food intake and improved HbA1c and glucose tolerance. Islet size was decreased, with no discernible change in islet number. The beneficial effects of the Lys(37) short-linker peptide were similar to or better than either exenatide or liraglutide, another GLP-1-R agonist. In conclusion, GLP-1 peptides conjugated to an ATIII binding carrier pentasaccharide have a substantially prolonged bioactive profile compatible for possible once-weekly treatment of type 2 diabetes in humans. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Rational design and synthesis of altered peptide ligands based on human myelin oligodendrocyte glycoprotein 35-55 epitope: inhibition of chronic experimental autoimmune encephalomyelitis in mice.

    Science.gov (United States)

    Tselios, Theodore; Aggelidakis, Mihalis; Tapeinou, Anthi; Tseveleki, Vivian; Kanistras, Ioannis; Gatos, Dimitrios; Matsoukas, John

    2014-11-04

    Experimental autoimmune encephalomyelitis (EAE) is a demyelinating disease of the central nervous system and is an animal model of multiple sclerosis (MS). Although the etiology of MS remains unclear, there is evidence T-cell recognition of immunodominant epitopes of myelin proteins, such as the 35-55 epitope of myelin oligodendrocyte glycoprotein (MOG), plays a pathogenic role in the induction of chronic EAE. Cyclization of peptides is of great interest since the limited stability of linear peptides restricts their potential use as therapeutic agents. Herein, we have designed and synthesized a number of linear and cyclic peptides by mutating crucial T cell receptor (TCR) contact residues of the human MOG35-55 epitope. In particular, we have designed and synthesized cyclic altered peptide ligands (APLs) by mutating Arg41 with Ala or Arg41 and Arg46 with Ala. The peptides were synthesized in solid phase on 2-chlorotrityl chloride resin (CLTR-Cl) using the Fmoc/t-Bu methodology. The purity of final products was verified by RP-HPLC and their identification was achieved by ESI-MS. It was found that the substitutions of Arg at positions 41 and 46 with Ala results in peptide analogues that reduce the severity of MOG-induced EAE clinical symptoms in C57BL/6 mice when co-administered with mouse MOG35-55 peptide at the time of immunization.

  19. Synthesis and characterization of Her2-NLP peptide conjugates targeting circulating breast cancer cells: cellular uptake and localization by fluorescent microscopic imaging.

    Science.gov (United States)

    Cai, Huawei; Singh, Ajay N; Sun, Xiankai; Peng, Fangyu

    2015-01-01

    To synthesize a fluorescent Her2-NLP peptide conjugate consisting of Her2/neu targeting peptide and nuclear localization sequence peptide (NLP) and assess its cellular uptake and intracellular localization for radionuclide cancer therapy targeting Her2/neu-positive circulating breast cancer cells (CBCC). Fluorescent Cy5.5 Her2-NLP peptide conjugate was synthesized by coupling a bivalent peptide sequence, which consisted of a Her2-binding peptide (NH2-GSGKCCYSL) and an NLP peptide (CGYGPKKKRKVGG) linked by a polyethylene glycol (PEG) chain with 6 repeating units, with an activated Cy5.5 ester. The conjugate was separated and purified by HPLC and then characterized by Maldi-MS. The intracellular localization of fluorescent Cy5.5 Her2-NLP peptide conjugate was assessed by fluorescent microscopic imaging using a confocal microscope after incubation of Cy5.5-Her2-NLP with Her2/neu positive breast cancer cells and Her2/neu negative control breast cancer cells, respectively. Fluorescent signals were detected in cytoplasm of Her2/neu positive breast cancer cells (SKBR-3 and BT474 cell lines), but not or little in cytoplasm of Her2/neu negative breast cancer cells (MDA-MB-231), after incubation of the breast cancer cells with Cy5.5-Her2-NLP conjugates in vitro. No fluorescent signals were detected within the nuclei of Her2/neu positive SKBR-3 and BT474 breast cancer cells, neither Her2/neu negative MDA-MB-231 cells, incubated with the Cy5.5-Her2-NLP peptide conjugates, suggesting poor nuclear localization of the Cy5.5-Her2-NLP conjugates localized within the cytoplasm after their cellular uptake and internalization by the Her2/neu positive breast cancer cells. Her2-binding peptide (KCCYSL) is a promising agent for radionuclide therapy of Her2/neu positive breast cancer using a β(-) or α emitting radionuclide, but poor nuclear localization of the Her2-NLP peptide conjugates may limit its use for eradication of Her2/neu-positive CBCC using I-125 or other Auger electron

  20. Chemical methods for peptide and protein production.

    Science.gov (United States)

    Chandrudu, Saranya; Simerska, Pavla; Toth, Istvan

    2013-04-12

    Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported α-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry.

  1. Chemical Methods for Peptide and Protein Production

    Directory of Open Access Journals (Sweden)

    Istvan Toth

    2013-04-01

    Full Text Available Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported a-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry.

  2. Technologies for the Synthesis of mRNA-Encoding Libraries and Discovery of Bioactive Natural Product-Inspired Non-Traditional Macrocyclic Peptides

    Directory of Open Access Journals (Sweden)

    Hiroaki Suga

    2013-03-01

    Full Text Available In this review, we discuss emerging technologies for drug discovery, which yields novel molecular scaffolds based on natural product-inspired non-traditional peptides expressed using the translation machinery. Unlike natural products, these technologies allow for constructing mRNA-encoding libraries of macrocyclic peptides containing non-canonical sidechains and N-methyl-modified backbones. The complexity of sequence space in such libraries reaches as high as a trillion (>1012, affording initial hits of high affinity ligands against protein targets. Although this article comprehensively covers several related technologies, we discuss in greater detail the technical development and advantages of the Random non-standard Peptide Integration Discovery (RaPID system, including the recent identification of inhibitors against various therapeutic targets.

  3. On-line enzymatic tailoring of polyketides and peptides in thiotemplate systems.

    Science.gov (United States)

    Sundaram, Srividhya; Hertweck, Christian

    2016-04-01

    Non-ribosomal peptide synthetases (NRPS) and type I polyketide synthases (PKS) are versatile thiotemplate systems for the programmed assembly of biosynthetic building blocks. Typically, the post-PKS/NRPS enzymes tailor the resulting chains to yield the bioactive natural product scaffolds. However, more and more examples have surfaced showing that important structural modifications take place while the intermediates are still bound to the assembly line. A growing number of enzymatic domains and trans-acting enzymes as well as their recruiting areas in the modules have been identified and characterized. In addition to the widespread on-line alkylations, hydroxylations and heterocyclizations into oxazole/thiazole residues, on-line modifications lead to a variety of ring systems such as cycloethers, lactones, lactams, glutarimides, cyclopropanes, decalins and cyclic biaryls. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Design, Synthesis, and Use of Peptides Derived from Human Papillomavirus L1 Protein for the Modification of Gold Electrode Surfaces by Self-Assembled Monolayers.

    Science.gov (United States)

    Lara Carrillo, John Alejandro; Fierro Medina, Ricardo; Manríquez Rocha, Juan; Bustos Bustos, Erika; Insuasty Cepeda, Diego Sebastián; García Castañeda, Javier Eduardo; Rivera Monroy, Zuly Jenny

    2017-11-14

    In order to obtain gold electrode surfaces modified with Human Papillomavirus L1 protein (HPV L1)-derived peptides, two sequences, SPINNTKPHEAR and YIK, were chosen. Both have been recognized by means of sera from patients infected with HPV. The molecules, Fc-Ahx-SPINNTKPHEAR, Ac-C- Ahx -(Fc)KSPINNTKPHEAR, Ac-C- Ahx -SPINNTKPHEAR(Fc)K, C- Ahx -SPINNTKPHEAR, and (YIK)₂- Ahx -C, were designed, synthesized, and characterized. Our results suggest that peptides derived from the SPINNTKPHEAR sequence, containing ferrocene and cysteine residues, are not stable and not adequate for electrode surface modification. The surface of polycrystalline gold electrodes was modified with the peptides C-Ahx-SPINNTKPHEAR or (YIK)₂-Ahx-C through self-assembly. The modified polycrystalline gold electrodes were characterized via infrared spectroscopy and electrochemical measurements. The thermodynamic parameters, surface coverage factor, and medium pH effect were determined for these surfaces. The results indicate that surface modification depends on the peptide sequence (length, amino acid composition, polyvalence, etc.). The influence of antipeptide antibodies on the voltammetric response of the modified electrode was evaluated by comparing results obtained with pre-immune and post-immune serum samples.

  5. Phase transfer synthesis of N,N'(1,2-phenylene)bis-hippuricamide tethered metal based functionalized nanoparticles: A study on some novel microbial targeting peptide-mimic nanoparticles

    International Nuclear Information System (INIS)

    Raman, N.; Sudharsan, S.

    2011-01-01

    This paper presents the novel synthesis of peptide, N,N'(1,2-phenylene)bis-hippuricamide tethered metal [Cu(II), Zn(II), Ni(II) and Co(II)] based functionalized nanoparticles via modified Brust-Schiffrin methodology. The growth, organic composition and morphology of these functionalized nanoparticles have been evaluated by UV-Vis, FT-IR spectroscopy and scanning electron microscopy. They are structurally and thermally characterized by X-ray diffraction and thermogravimetric analysis. Moreover, the interfacial dealings of these functionalized nanoparticles with Calf-thymus DNA and pUC19 DNA reveal that the functionalized nanoparticles of cobalt is an effective DNA damaging agent under physiological conditions. This has been supported by its efficient antimicrobial character against few fungal and bacterial strains, thereby steering its way towards biomedical applications as a metal based nanocarrier.

  6. Construction and in vitro analysis of a new bi-modular polypeptide synthetase for synthesis of N-methylated acyl peptides.

    Science.gov (United States)

    Schauwecker, F; Pfennig, F; Grammel, N; Keller, U

    2000-04-01

    Many active peptides are synthesized by nonribosomal peptide synthetases (NRPSs), large multimodular enzymes. Each module incorporates one amino acid, and is composed of two domains: an activation domain that activates the substrate amino acid and a condensation domain for peptide-bond formation. Activation domains sometimes contain additional activities (e.g. N-methylation or epimerization). Novel peptides can be generated by swapping domains. Exchange of domains containing N-methylation activity has not been reported, however. The actinomycin NRPS was used to investigate domain swapping. The first two amino acids of actinomycin are threonine and valine. We replaced the valine activation domain of module 2 with an N-methyl valine (MeVal) activation domain. The recombinant NRPS (AcmTmVe) catalyzes the formation of threonyl-valine. In the presence of S-adenosyl-methionine, valine was converted to MeVal but subsequent dipeptide formation was blocked. When acyl-threonine (the natural intermediate) was present at module 1, formation of acyl-threonine-MeVal occurred. The epimerization domain of AcmTmVe was impaired. A simple activation domain can be replaced by one with N-methylation activity. The same condensation domain can catalyze peptide-bond formation between N-methyl and nonmethylated amino acids. Modification of the upstream amino acid (i.e. acylation of threonine), however, was required for condensation with MeVal. Steric hindrance reduces chemical reactivity of N-methyl amino acids - perfect substrate positioning may only be achieved with acylated threonine. Loss of the epimerase activity of AcmTmVe suggests N-methyltransferase and epimerase domains, not found together naturally, are incompatible.

  7. Total synthesis of cyclomarins A, C and D, marine cyclic peptides with interesting anti-tuberculosis and anti-malaria activities.

    Science.gov (United States)

    Barbie, Philipp; Kazmaier, Uli

    2016-07-07

    Cyclomarins are cyclic heptapeptides containing four unusual amino acids. New synthetic protocols toward their synthesis have been developed, leading to the synthesis and biological evaluation of three natural occurring cyclomarins. Interestingly, cyclomarins address two completely different targets: Clp C1, a subunit of the caseinolytic protease of Mycobacterium tuberculosis (MTB), as well as PfAp3Ase of Plasmodium falciparum. Therefore, cyclomarins are interesting lead structures for the development of drugs against tuberculosis and malaria.

  8. Comparative syntheses of peptides and peptide thioesters derived from mouse and human prion proteins

    Czech Academy of Sciences Publication Activity Database

    Šebestík, Jaroslav; Zawada, Zbigniew; Šafařík, Martin; Hlaváček, Jan

    2012-01-01

    Roč. 43, č. 3 (2012), s. 1297-1309 ISSN 0939-4451 R&D Projects: GA ČR GA203/07/1517 Institutional research plan: CEZ:AV0Z40550506 Keywords : prion protein segments * classical synthesis * chemical ligation synthesis * peptide thioesters Subject RIV: CC - Organic Chemistry Impact factor: 3.914, year: 2012

  9. Material Binding Peptides for Nanotechnology

    Directory of Open Access Journals (Sweden)

    Urartu Ozgur Safak Seker

    2011-02-01

    Full Text Available Remarkable progress has been made to date in the discovery of material binding peptides and their utilization in nanotechnology, which has brought new challenges and opportunities. Nowadays phage display is a versatile tool, important for the selection of ligands for proteins and peptides. This combinatorial approach has also been adapted over the past decade to select material-specific peptides. Screening and selection of such phage displayed material binding peptides has attracted great interest, in particular because of their use in nanotechnology. Phage display selected peptides are either synthesized independently or expressed on phage coat protein. Selected phage particles are subsequently utilized in the synthesis of nanoparticles, in the assembly of nanostructures on inorganic surfaces, and oriented protein immobilization as fusion partners of proteins. In this paper, we present an overview on the research conducted on this area. In this review we not only focus on the selection process, but also on molecular binding characterization and utilization of peptides as molecular linkers, molecular assemblers and material synthesizers.

  10. Synthesis of antifungal vaccines by conjugation of β-1,2 trimannosides with T-cell peptides and covalent anchoring of neoglycopeptide to tetanus toxoid.

    Science.gov (United States)

    Cartmell, Jonathan; Paszkiewicz, Eugenia; Dziadek, Sebastian; Tam, Pui-Hang; Luu, Thanh; Sarkar, Susmita; Lipinski, Tomasz; Bundle, David R

    2015-02-11

    Selective strategies for the construction of novel three component glycoconjugate vaccines presenting Candida albicans cell wall glycan (β-1,2 mannoside) and polypeptide fragments on a tetanus toxoid carrier are described. The first of two conjugation strategies employed peptides bearing an N-terminal thiopropionyl residue for conjugation to a trisaccharide equipped with an acrylate linker and a C-terminal S-acetyl thioglycolyl moiety for subsequent linking of neoglycopeptide to bromoacetylated tetanus toxoid. Michael addition of acrylate trisaccharides to peptide thiol under mildly basic conditions gave a mixture of N- and C- terminal glyco-peptide thioethers. An adaptation of this strategy coordinated S-acyl protection with anticipated thioester exchange equilibria. This furnished a single chemically defined fully synthetic neoglycopeptide conjugate that could be anchored to a tetanus toxoid carrier and avoids the introduction of exogenous antigenic groups. The second strategy retained the N-terminal thiopropionyl residue but replaced the C-terminal S-acetate functionality with an azido group that allowed efficient, selective formation of neoglycopeptide thioethers and subsequent conjugation of these with propargylated tetanus toxoid, but introduced potentially antigenic triazole linkages. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. 14C-labeling of synthetic peptides

    International Nuclear Information System (INIS)

    Chersi, A.; Trinca, M.L.; Camera, M.

    1988-01-01

    Two methods are described for the labelling of synthetic peptides using iodo[ 14 C]acetic acid. The first procedure may be employed when the synthetic fragment contains a cysteine with a free sulfhydryl group. Alternatively, a commercial amino-protected cysteine may be carboxymethylated using radioactive iodoacetic acid. This derivative can be added to the growing peptide chain in the manual or automatic solid-phase synthesis of the fragment. 9 refs.; 1 figure; 1 table

  12. 14C-labeling of synthetic peptides.

    Science.gov (United States)

    Chersi, A; Trinca, M L; Camera, M

    1988-06-13

    Two methods are described for the labeling of synthetic peptides using iodo[14C]acetic acid. The first procedure may be employed when the synthetic fragment contains a cysteine with a free sulfhydryl group. Alternatively, a commercial amino-protected cysteine may be carboxymethylated using radioactive iodoacetic acid. This derivative can be added to the growing peptide chain in the manual or automatic solid-phase synthesis of the fragment.

  13. Natriuretic Peptides: Biochemistry, Physiology, Clinical Implication

    Directory of Open Access Journals (Sweden)

    I. A. Kozlova

    2009-01-01

    Full Text Available In the past years, the interest of theorists and clinicians has steadily increased in the myocardially secreted hormones – natriuretic peptides. At the Congress of the European Society of Anesthesiology (Munich, 2007, B-type natriuretic peptides were included into the list of the parameters of perioperative laboratory monitoring that is expedient in the practice of anesthetists and resuscitation specialists. The literature review shows the history of discovery and identification of different types of natriuretic peptides and considers the matters of their biochemistry. It also details information on the synthesis, secretion, and clearance of these peptides, as well as their receptor apparatus in various organs and tissues. The physiology of the regulatory system is described, as applied to the cardiovascular, excretory, central nervous systems, and the neuroendocrine one. Special attention is given to the current publications on the control of B-type natriuretic peptides as biomarkers of cardiac dysfunction. The diagnostic and prognostic values of peptides are analyzed in chronic circulatory insufficiency, coronary heart disease, and other car-diological and non-cardiological diseases. The prognostic value of elevated B-type natriuretic peptide levels in cardiac surgery is separately considered. It is concluded that the changes in the level of B-type natriuretic peptides in different clinical situations are the subject of numerous researches mainly made in foreign countries. The bulk of these researches are devoted to the study of peptides in cardiology and other areas of therapy. Studies on the use of peptides in reanimatology are relatively few and their results are rather discordant. The foregoing opens up wide prospects for studying the use of B-type natriuretic peptides in Russian intensive care and anesthesiology. Key words: natriuretic peptides, brain nautriuretic peptides, NT-proBNP.

  14. Synthesis, 2D-NMR and molecular modelling studies of pentacycloundecane lactam-peptides and peptoids as potential HIV-1 wild type C-SA protease inhibitors.

    Science.gov (United States)

    Makatini, Maya M; Petzold, Katja; Alves, Cláudio Nahum; Arvidsson, Per I; Honarparvar, Bahareh; Govender, Patrick; Govender, Thavendran; Kruger, Hendrik G; Sayed, Yasien; JerônimoLameira; Maguire, Glenn E M; Soliman, Mahmoud E S

    2013-02-01

    In this study, eight non-natural peptides and peptoids incorporating the pentacycloundecane (PCU) lactam were designed and synthesized as potential inhibitors of the wild type C-SA HIV-protease. Five of these inhibitors gave IC(50) values ranging from 0.5 up to 0.75 µM against the resistance-prone wild type C-South African HIV-protease. NMR EASY-ROESY studies enabled us to describe the secondary structure of three of these compounds in solution. The 3D structures of the selected cage peptides were also modelled in solution using QM/MM/MD simulations. Satisfactory agreement between the NMR observations and the low energy calculated structures exists. Only one of these inhibitors (11 peptoid), which showed the best IC(50)(0.5 µM), exhibited a definable 3-D structure in solution. Autodock4 and AutodockVina were used to model the potential interaction between these inhibitors and the HIV-PR. It appears that the docking results are too crude to be correlated with the relative narrow range of experimental IC(50) values (0.5-10 µM). The PCU-peptides and peptoides were several orders less toxic (145 μM for 11 and 102 μM for 11 peptoid) to human MT-4 cells than lopinavir (0.025 μM). This is the first example of a polycyclic cage framework to be employed as an HIV-PR transition state analogue inhibitor and can potentially be utilized for other diseases related proteases. [Figure: see text].

  15. Potent μ-Opioid Receptor Agonists from Cyclic Peptides Tyr-c[D-Lys-Xxx-Tyr-Gly]: Synthesis, Biological, and Structural Evaluation.

    Science.gov (United States)

    Li, Yangmei; Cazares, Margret; Wu, Jinhua; Houghten, Richard A; Toll, Laurence; Dooley, Colette

    2016-02-11

    To optimize the structure of a μ-opioid receptor ligand, analogs H-Tyr-c[D-Lys-Xxx-Tyr-Gly] were synthesized and their biological activity was tested. The analog containing a Phe(3) was identified as not only exhibiting binding affinity 14-fold higher than the original hit but also producing agonist activity 3-fold more potent than morphine. NMR study suggested that a trans conformation at D-Lys(2)-Xxx(3) is crucial for these cyclic peptides to maintain high affinity, selectivity, and functional activity toward the μ-opioid receptor.

  16. Synthesis, antibacterial activity, and biological evaluation of formyl hydroxyamino derivatives as novel potent peptide deformylase inhibitors against drug-resistant bacteria.

    Science.gov (United States)

    Yang, Shouning; Shi, Wei; Xing, Dong; Zhao, Zheng; Lv, Fengping; Yang, Liping; Yang, Yushe; Hu, Wenhao

    2014-10-30

    Peptide deformylase (PDF) has been identified as a promising target for novel antibacterial agents. In this study, a series of novel formyl hydroxyamino derivatives were designed and synthesized as PDF inhibitors and their antibacterial activities were evaluated. Among the potent PDF inhibitors (1o, 1q, 1o', 1q', and 1x), in vivo studies showed that compound 1q possesses mild toxicity, a good pharmacokinetic profile and protective effects. The good in vivo efficacy and low toxicity suggest that this class of compounds has potential for development and use in future antibacterial drugs. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  17. Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Ali Adem Bahar

    2013-11-01

    Full Text Available The rapid increase in drug-resistant infections has presented a serious challenge to antimicrobial therapies. The failure of the most potent antibiotics to kill “superbugs” emphasizes the urgent need to develop other control agents. Here we review the history and new development of antimicrobial peptides (AMPs, a growing class of natural and synthetic peptides with a wide spectrum of targets including viruses, bacteria, fungi, and parasites. We summarize the major types of AMPs, their modes of action, and the common mechanisms of AMP resistance. In addition, we discuss the principles for designing effective AMPs and the potential of using AMPs to control biofilms (multicellular structures of bacteria embedded in extracellular matrixes and persister cells (dormant phenotypic variants of bacterial cells that are highly tolerant to antibiotics.

  18. Optimization of synthesis and quality control procedures for the preparation of 18F and 123I labelled peptides for nuclear medicine

    International Nuclear Information System (INIS)

    2002-09-01

    The general scope of this CRP focused on the optimization of syntheses, quality control, in vitro and in vivo evaluation of 18 F and 123 I radiopharmaceuticals based on peptides with known or anticipated clinical potential. Selective labelling procedures using prosthetic groups were applied to both fluorine and iodine. Studies included investigation on the fate of the label, stability in vivo, biodistribution and pharmacokinetic studies in rodents and in cell culture. With respect to 123 I, the work aimed at developing a simplified labelling kit using solid state systems. The first Research Co-ordination Meeting (RCM) that was held in August 1997 took up and decided on the criteria for selecting the peptides and agreed upon a set of recommended laboratory protocols for the CRP participants to follow and further optimize. Eight scientists from reputed laboratories from Argentina, Brazil, China, Germany, Greece, the Islamic Republic of Iran, Saudi Arabia and the United States of America participated in the CRP. Three RCMs were held where the participants presented their scientific results: August 1997 in Sao Paulo, Brazil, April 1999 in Athens, Greece, and November 2000 in Shanghai, People's Republic of China. Reports describing the research work of all participants are included herein. Each of the report has been indexed separately

  19. Synthesis, characterization and applications of carboxylated and polyethylene-glycolated bifunctionalized InP/ZnS quantum dots in cellular internalization mediated by cell-penetrating peptides.

    Science.gov (United States)

    Liu, Betty R; Winiarz, Jeffrey G; Moon, Jong-Sik; Lo, Shih-Yen; Huang, Yue-Wern; Aronstam, Robert S; Lee, Han-Jung

    2013-11-01

    Semiconductor nanoparticles, also known as quantum dots (QDs), are widely used in biomedical imaging studies and pharmaceutical research. Cell-penetrating peptides (CPPs) are a group of small peptides that are able to traverse cell membrane and deliver a variety of cargoes into living cells. CPPs deliver QDs into cells with minimal nonspecific absorption and toxic effect. In this study, water-soluble, monodisperse, carboxyl-functionalized indium phosphide (InP)/zinc sulfide (ZnS) QDs coated with polyethylene glycol lipids (designated QInP) were synthesized for the first time. The physicochemical properties (optical absorption, fluorescence and charging state) and cellular internalization of QInP and CPP/QInP complexes were characterized. CPPs noncovalently interact with QInP in vitro to form stable CPP/QInP complexes, which can then efficiently deliver QInP into human A549 cells. The introduction of 500nM of CPP/QInP complexes and QInP at concentrations of less than 1μM did not reduce cell viability. These results indicate that carboxylated and polyethylene-glycolylated (PEGylated) bifunctionalized QInP are biocompatible nanoparticles with potential for use in biomedical imaging studies and drug delivery applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Preparation and utilization of fluorescent synthetic peptides.

    Science.gov (United States)

    Chersi, A; Sezzi, M L; Romano, T F; Evangelista, M; Nista, A

    1990-06-20

    In this study, several methods for controlled labelling of synthetic peptides by the use of fluorescent compounds (fluorescein isothiocyanate and dimethylaminonaphthalene sulfonyl chloride) were investigated. The first reagent yielded monofluoresceinated, active compounds only when the peptides lacked lysine residues. Monolabelling of peptides in solution with dimethylaminonaphthalenesulphonyl chloride was hindered by the broad reactivity of the reagent, but was achieved by reacting the fluorochrome on protected resin-bound peptides in solid-phase synthesis. The remarkable stability of the linkage allowed the cleavage of the peptide from the resin and deprotection of side-chain functions without hydrolysis of the labelled group. The binding of antipeptide antibodies to the labelled fragments was then estimated using different techniques.

  1. Repression of branched-chain amino acid synthesis in Staphylococcus aureus is mediated by isoleucine via CodY, and by a leucine-rich attenuator peptide.

    Directory of Open Access Journals (Sweden)

    Julienne C Kaiser

    2018-01-01

    Full Text Available Staphylococcus aureus requires branched-chain amino acids (BCAAs; isoleucine, leucine, valine for protein synthesis, branched-chain fatty acid synthesis, and environmental adaptation by responding to their availability via the global transcriptional regulator CodY. The importance of BCAAs for S. aureus physiology necessitates that it either synthesize them or scavenge them from the environment. Indeed S. aureus uses specialized transporters to scavenge BCAAs, however, its ability to synthesize them has remained conflicted by reports that it is auxotrophic for leucine and valine despite carrying an intact BCAA biosynthetic operon. In revisiting these findings, we have observed that S. aureus can engage in leucine and valine synthesis, but the level of BCAA synthesis is dependent on the BCAA it is deprived of, leading us to hypothesize that each BCAA differentially regulates the biosynthetic operon. Here we show that two mechanisms of transcriptional repression regulate the level of endogenous BCAA biosynthesis in response to specific BCAA availability. We identify a trans-acting mechanism involving isoleucine-dependent repression by the global transcriptional regulator CodY and a cis-acting leucine-responsive attenuator, uncovering how S. aureus regulates endogenous biosynthesis in response to exogenous BCAA availability. Moreover, given that isoleucine can dominate CodY-dependent regulation of BCAA biosynthesis, and that CodY is a global regulator of metabolism and virulence in S. aureus, we extend the importance of isoleucine availability for CodY-dependent regulation of other metabolic and virulence genes. These data resolve the previous conflicting observations regarding BCAA biosynthesis, and reveal the environmental signals that not only induce BCAA biosynthesis, but that could also have broader consequences on S. aureus environmental adaptation and virulence via CodY.

  2. Post-translational modification of ribosomally synthesized peptides by a radical SAM epimerase in Bacillus subtilis

    Science.gov (United States)

    Benjdia, Alhosna; Guillot, Alain; Ruffié, Pauline; Leprince, Jérôme; Berteau, Olivier

    2017-07-01

    Ribosomally synthesized peptides are built out of L-amino acids, whereas D-amino acids are generally the hallmark of non-ribosomal synthetic processes. Here we show that the model bacterium Bacillus subtilis is able to produce a novel type of ribosomally synthesized and post-translationally modified peptide that contains D-amino acids, and which we propose to call epipeptides. We demonstrate that a two [4Fe-4S]-cluster radical S-adenosyl-L-methionine (SAM) enzyme converts L-amino acids into their D-counterparts by catalysing Cα-hydrogen-atom abstraction and using a critical cysteine residue as the hydrogen-atom donor. Unexpectedly, these D-amino acid residues proved to be essential for the activity of a peptide that induces the expression of LiaRS, a major component of the bacterial cell envelope stress-response system. Present in B. subtilis and in several members of the human microbiome, these epipeptides and radical SAM epimerases broaden the landscape of peptidyl structures accessible to living organisms.

  3. Synthesis of Biotin Linkers with the Activated Triple Bond Donor [p-(N-propynoylaminotoluic Acid] (PATA for Efficient Biotinylation of Peptides and Oligonucleotides

    Directory of Open Access Journals (Sweden)

    Martina Jezowska

    2012-11-01

    Full Text Available Biotin is an important molecule for modern biological studies including, e.g., cellular transport. Its exclusive affinity to fluorescent streptavidin/avidin proteins allows ready and specific detection. As a consequence methods for the attachment of biotin to various biological targets are of high importance, especially when they are very selective and can also proceed in water. One useful method is Hüisgen dipolar [3+2]-cycloaddition, commonly referred to as “click chemistry”. As we reported recently, the activated triple bond donor p-(N-propynoylaminotoluic acid (PATA gives excellent results when used for conjugations at submicromolar concentrations. Thus, we have designed and synthesized two biotin linkers, with different lengths equipped with this activated triple bond donor and we proceeded with biotinylation of oligonucleotides and C-myc peptide both in solution and on solid support with excellent yields of conversion.

  4. Synthesis and pharmacology of novel analogues of oxytocin and deaminooxytocin: directed methods for the construction of disulfide and trisulfide bridges in peptides.

    Science.gov (United States)

    Chen, L; Zoulíková, I; Slaninová, J; Barany, G

    1997-03-14

    Using as models the neurohypophyseal nonapeptide hormone oxytocin and its analogue deaminooxytocin, several directed routes to formation of sulfur-sulfur bridges have been developed and evaluated. The linear sequences (through common octapeptide-resin intermediates) were assembled smoothly on tris(alkoxy)benzylamide (PAL) poly(ethylene glycol)-polystyrene (PEG-PS) graft supports, using stepwise Fmoc solid-phase chemistry. Side-chain protection of beta-mercaptopropionic acid (Mpa) and/or cysteine (Cys) was provided by S-2,4,6-trimethoxybenzyl (Tmob), S-acetamidomethyl (Acm), and/or a series of sulfenyl thiocarbonate and carbamoylsulfenyl protecting/activating groups: S-(methoxycarbonyl)sulfenyl (Scm), S-(methoxycarbonyl)disulfanyl (Sscm), S-(N-methyl-N-phenylcarbamoyl)sulfenyl (Snm), and S-(N-methyl-N-phenylcarbamoyl)disulfanyl (Ssnm). Thiolytic displacement of S-Snm (preferred) or S-Scm provided intramolecular cyclized peptide disulfides, and homologation of the chemistry with S-Ssnm (again preferred) and S-Sscm provided the corresponding trisulfides along with smaller amounts of disulfides and tetrasulfides. These chemistries could be implemented both in solution and in solid-phase modes. Various parameters were studied systematically and optimized, and the novel trisulfides of oxytocin and deaminooxytocin were synthesized and purified to homogeneity. The trisulfide compounds were evaluated in three assays: uterotonic in vitro, uterotonic in vivo, and pressor tests, and they showed substantial potencies, ranging from 5% to 40% of the parent (disulfide) activities, as well as protracted actions. The affinities of the peptide trisulfides to uterine membrane receptors were only 3.3-3.6-fold lower than those of the parent disulfides. Possible explanations of the biological results are discussed.

  5. One pot synthesis of highly luminescent polyethylene glycol anchored carbon dots functionalized with a nuclear localization signal peptide for cell nucleus imaging

    Science.gov (United States)

    Yang, Lei; Jiang, Weihua; Qiu, Lipeng; Jiang, Xuewei; Zuo, Daiying; Wang, Dongkai; Yang, Li

    2015-03-01

    Strong blue fluorescent polyethylene glycol (PEG) anchored carbon nitride dots (CDs@PEG) with a high quantum yield (QY) of 75.8% have been synthesized by a one step hydrothermal treatment. CDs with a diameter of ca. 6 nm are well dispersed in water and present a graphite-like structure. Photoluminescence (PL) studies reveal that CDs display excitation-dependent behavior and are stable under various test conditions. Based on the as-prepared CDs, we designed novel cell nucleus targeting imaging carbon dots functionalized with a nuclear localization signal (NLS) peptide. The favourable biocompatibilities of CDs and NLS modified CDs (NLS-CDs) are confirmed by in vitro cytotoxicity assays. Importantly, intracellular localization experiments in MCF7 and A549 cells demonstrate that NLS-CDs could be internalized in the nucleus and show blue light, which indicates that CDs may serve as cell nucleus imaging probes.Strong blue fluorescent polyethylene glycol (PEG) anchored carbon nitride dots (CDs@PEG) with a high quantum yield (QY) of 75.8% have been synthesized by a one step hydrothermal treatment. CDs with a diameter of ca. 6 nm are well dispersed in water and present a graphite-like structure. Photoluminescence (PL) studies reveal that CDs display excitation-dependent behavior and are stable under various test conditions. Based on the as-prepared CDs, we designed novel cell nucleus targeting imaging carbon dots functionalized with a nuclear localization signal (NLS) peptide. The favourable biocompatibilities of CDs and NLS modified CDs (NLS-CDs) are confirmed by in vitro cytotoxicity assays. Importantly, intracellular localization experiments in MCF7 and A549 cells demonstrate that NLS-CDs could be internalized in the nucleus and show blue light, which indicates that CDs may serve as cell nucleus imaging probes. Electronic supplementary information (ESI) available: The formulation of PEGylation CD optimization procedure, Table S1 and Fig. S1-S7. See DOI: 10.1039/c5nr01080

  6. Synthesis, photophysical properties of triazolyl-donor/acceptor chromophores decorated unnatural amino acids: Incorporation of a pair into Leu-enkephalin peptide and application of triazolylperylene amino acid in sensing BSA.

    Science.gov (United States)

    Bag, Subhendu Sekhar; Jana, Subhashis; Pradhan, Manoj Kumar

    2016-08-15

    The research in the field of design and synthesis of unnatural amino acids is growing at a fast space for the increasing demand of proteins of potential therapeutics and many other diversified novel functional applications. Thus, we report herein the design and synthesis of microenvironment sensitive fluorescent triazolyl unnatural amino acids (UNAA) decorated with donor and/or acceptor aromatic chromophores via click chemistry. The synthesized fluorescent amino acids show interesting solvatochromic characteristic and/or intramolecular charge transfer (ICT) feature as is revealed from the UV-visible, fluorescence photophysical properties and DFT/TDDFT calculation. HOMO-LUMO distribution shows that the emissive states of some of the amino acids are characterized with more significant electron redistribution between the triazolyl moiety and the aromatic chromophores linked to it leading to modulated emission property. A pair of donor-acceptor amino acid shows interesting photophysical interaction property indicating a FRET quenching event. Furthermore, one of the amino acid, triazolyl-perylene amino acid, has been exploited for studying interaction with BSA and found that it is able to sense BSA with an enhancement of fluorescence intensity. Finally, we incorporated a pair of donor/acceptor amino acids into a Leu-enkephalin analogue pentapeptide which was found to adopt predominantly type II β-turn conformation. We envisage that our investigation is of importance for the development of new fluorescent donor-acceptor unnatural amino acids a pair of which can be exploited for generating fluorescent peptidomimetic probe of interesting photophysical property for applications in studying peptide-protein interaction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Peptide regulators of insect reproduction containing D-amino acids

    Czech Academy of Sciences Publication Activity Database

    Hlaváček, Jan; Bennettová, Blanka; Slaninová, Jiřina; Černý, B.; Vlasáková, Věra; Holík, Josef; Tykva, Richard

    2010-01-01

    Roč. 16, S1 (2010), s. 193-194 ISSN 1075-2617. [European Peptide Symposium /31./. 05.09.2010-09.09.2010, Copenhagen] R&D Projects: GA ČR GA203/06/1272 Institutional research plan: CEZ:AV0Z40550506 Keywords : D-amino acids * peptide synthesis * degradation * radioactivity accumulation Subject RIV: CC - Organic Chemistry

  8. Quest for the chemical synthesis of proteins.

    Science.gov (United States)

    Engelhard, Martin

    2016-05-01

    The chemical synthesis of proteins has been the wish of chemists since the early 19th century. There were decisive methodological steps necessary to accomplish this aim. Cornerstones were the introduction of the Z-protecting group of Bergmann and Zervas, the development of Solid-phase Peptide Synthesis of Merrifield, and the establishment of Native Chemical Ligation by Kent. Chemical synthesis of proteins has now become generally applicable technique for the synthesis of proteins with tailor made properties which can be applied not only in vitro but also in vivo .Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  9. DBAASP v.2: an enhanced database of structure and antimicrobial/cytotoxic activity of natural and synthetic peptides.

    Science.gov (United States)

    Pirtskhalava, Malak; Gabrielian, Andrei; Cruz, Phillip; Griggs, Hannah L; Squires, R Burke; Hurt, Darrell E; Grigolava, Maia; Chubinidze, Mindia; Gogoladze, George; Vishnepolsky, Boris; Alekseyev, Vsevolod; Rosenthal, Alex; Tartakovsky, Michael

    2016-01-04

    Antimicrobial peptides (AMPs) are anti-infectives that may represent a novel and untapped class of biotherapeutics. Increasing interest in AMPs means that new peptides (natural and synthetic) are discovered faster than ever before. We describe herein a new version of the Database of Antimicrobial Activity and Structure of Peptides (DBAASPv.2, which is freely accessible at http://dbaasp.org). This iteration of the database reports chemical structures and empirically-determined activities (MICs, IC50, etc.) against more than 4200 specific target microbes for more than 2000 ribosomal, 80 non-ribosomal and 5700 synthetic peptides. Of these, the vast majority are monomeric, but nearly 200 of these peptides are found as homo- or heterodimers. More than 6100 of the peptides are linear, but about 515 are cyclic and more than 1300 have other intra-chain covalent bonds. More than half of the entries in the database were added after the resource was initially described, which reflects the recent sharp uptick of interest in AMPs. New features of DBAASPv.2 include: (i) user-friendly utilities and reporting functions, (ii) a 'Ranking Search' function to query the database by target species and return a ranked list of peptides with activity against that target and (iii) structural descriptions of the peptides derived from empirical data or calculated by molecular dynamics (MD) simulations. The three-dimensional structural data are critical components for understanding structure-activity relationships and for design of new antimicrobial drugs. We created more than 300 high-throughput MD simulations specifically for inclusion in DBAASP. The resulting structures are described in the database by novel trajectory analysis plots and movies. Another 200+ DBAASP entries have links to the Protein DataBank. All of the structures are easily visualized directly in the web browser. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  10. Studies on peptide amidase-catalysed C-terminal peptide amidation in organic media with respect to its substrate specificity

    Czech Academy of Sciences Publication Activity Database

    Čeřovský, Václav; Kula, M. R.

    2001-01-01

    Roč. 33, - (2001), s. 183-187 ISSN 0885-4513 R&D Projects: GA ČR GA203/99/1458 Keywords : enzymic amidation * peptide amides * peptide synthesis Subject RIV: CC - Organic Chemistry Impact factor: 1.408, year: 2001

  11. Synthesis and antimicrobial evaluation of two peptide LyeTx I derivatives modified with the chelating agent HYNIC for radiolabeling with technetium-{sup 99m}

    Energy Technology Data Exchange (ETDEWEB)

    Fuscaldi, Leonardo Lima; Santos, Daniel Moreira dos; Pinheiro, Natalia Gabriela Silva; Araujo, Raquel Silva; Barros, Andre Luis Branco de; Resende, Jarbas Magalhaes; Fernandes, Simone Odilia Antunes; Lima, Maria Elena de; Cardoso, Valbert Nascimento, E-mail: valbertncardoso@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Analises Clinicas Toxicologica

    2016-11-01

    Background: Current diagnostic methods and imaging techniques are not able to differentiate septic and aseptic inflammation. Thus, reliable methods are sought to provide this distinction and scintigraphic imaging is an interesting option, since it is based on physiological changes. In this context, radiolabeled antimicrobial peptides have been investigated as they accumulate in infectious sites instead of aseptic inflammation. The peptide LyeTx I, from the venom of Lycosa erythrognatha, has potent antimicrobial activity. Therefore, this study aimed to synthesize LyeTx I derivatives with the chelating compound HYNIC, to evaluate their antimicrobial activity and to radiolabel them with {sup 99m}Tc. Methods: Two LyeTx I derivatives, HYNIC-LyeTx I (N-terminal modification) and LyeTx I-K-HYNIC (C-terminal modification), were synthesized by Fmoc strategy and purified by RP-HPLC. The purified products were assessed by RP-HPLC and MALDI-ToF-MS analysis. Microbiological assays were performed against S. aureus (ATCC® 6538) and E. coli (ATCC® 10536) in liquid medium to calculate the MIC. The radiolabeling procedure of LyeTx I-K-HYNIC with {sub 99m}Tc was performed in the presence of co-ligands (tricine and EDDA) and reducing agent (SnCl{sub 2} . 2H{sub 2}O), and standardized taking into account the amount of peptide, reducing agent, pH and heating. Radiochemical purity analysis was performed by thin-layer chromatography on silica gel strips and the radiolabeled compound was assessed by RP-HPLC and radioactivity measurement of the collected fractions. Data were analyzed by ANOVA, followed by Tukey test (p-values < 0.05). Results: Both LyeTx I derivatives were suitably synthesized and purified, as shown by RP-HPLC and MALDI-ToF-MS analysis. The microbiological test showed that HYNIC-LyeTx I (N-terminal modification) did not inhibit bacterial growth, whereas LyeTx I-K-HYNIC (C-terminal modification) showed a MIC of 5.05 μmol. L−1 (S. aureus) and 10.10 μmol. L−1 (E. coli

  12. Synthesis and evaluation of a radioiodinated peptide probe targeting αvβ6 integrin for the detection of pancreatic ductal adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Masashi [Radioisotopes Research Laboratory, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501 (Japan); Fukushima, Takahiro; Ogawa, Kei [Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501 (Japan); Kimura, Hiroyuki [Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501 (Japan); Radioisotope Research Center of Kyoto University, Kyoto 606-8501 (Japan); Ono, Masahiro [Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501 (Japan); Yamaguchi, Takashi; Ikehara, Yuzuru [Molecular Medicine Team, Research Center for Medical Glycoscience, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568 (Japan); Saji, Hideo, E-mail: hsaji@pharm.kyoto-u.ac.jp [Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501 (Japan)

    2014-03-14

    Highlights: • We developed a radioiodinated peptide probe targeting αvβ6 integrin ({sup 123}I-IFMDV2). • {sup 123}I-IFMDV2 had a high affinity and selectivity for αvβ6 integrin. • {sup 123}I-IFMDV2 showed a specific binding to αvβ6 integrin in vivo. • {sup 123}I-IFMDV2 enabled clear visualization of the αvβ6-integrin-positive tumor. - Abstract: Introduction: Pancreatic ductal adenocarcinoma (PDAC) remains a major cause of cancer-related death. Since significant upregulation of αvβ6 integrin has been reported in PDAC, this integrin is a promising target for PDAC detection. In this study, we aimed to develop a radioiodinated probe for the imaging of αvβ6 integrin-positive PDAC with single-photon emission computed tomography (SPECT). Methods: Four peptide probes were synthesized and screened by competitive and saturation binding assays using 2 PDAC cell lines (AsPC-1, αvβ6 integrin-positive; MIA PaCa-2, αvβ6 integrin-negative). The probe showing the best affinity was used to study the biodistribution assay, an in vivo blocking study, and SPECT imaging using tumor bearing mice. Autoradiography and immunohistochemical analysis were also performed. Results: Among the 4 probes examined in this study, {sup 125}I-IFMDV2 showed the highest affinity for αvβ6 integrin expressed in AsPC-1 cells and no affinity for MIA PaCa-2 cells. The accumulation of {sup 125}I-IFMDV2 in the AsPC-1 xenograft was 3–5 times greater than that in the MIA PaCa-2 xenograft, consistent with the expression of αvβ6 integrin in each xenograft, and confirmed by immunohistochemistry. Pretreatment with excess amounts of A20FMDV2 significantly blocked the accumulation of {sup 125}I-IFMDV2 in the AsPC-1 xenograft, but not in the MIA PaCa-2 xenograft. Furthermore, {sup 123}I-IFMDV2 enabled clear visualization of the AsPC-1 xenograft. Conclusion: {sup 123}I-IFMDV2 is a potential SPECT probe for the imaging of αvβ6 integrin in PDAC.

  13. Synthetic antifreeze peptide

    OpenAIRE

    1991-01-01

    A synthetic antifreeze peptide and a synthetic gene coding for the antifreeze peptide have been produced. The antifreeze peptide has a greater number of repeating amino acid sequences than is present in the native antifreeze peptides from winter flounder upon which the synthetic antifreeze peptide was modeled. Each repeating amino acid sequence has two polar amino acid residues which are spaced a controlled distance apart so that the antifreeze peptide may inhibit ice formation. The synthetic...

  14. Multicomponent Aqueous Synthesis of Iodo-1,2,3-triazoles: Single-Step Models for Dual Modification of Free Peptide and Radioactive Iodo Labeling.

    Science.gov (United States)

    Li, Lingjun; Ding, Shengqiang; Yang, Yanping; Zhu, Anlian; Fan, Xincui; Cui, Mengchao; Chen, Changpo; Zhang, Guisheng

    2017-01-23

    Iodo-1,2,3-triazoles are of considerable interest for chemical and biomedical applications. However, current synthetic methods for preparing iodo-1,2,3-triazoles cannot easily be applied to the direct modification of bioactive molecules in water. Through the combination of water-compatible oxidative iodination and the copper-catalyzed alkyne-azide cycloaddition reaction, a novel copper-catalyzed aqueous multicomponent synthetic method for the preparation of 5-iodo-1,2,3-triazoles has been developed. The method is highly effective and selective for substrates including biologically relevant compounds with nucleoside, sugar, and amino acid moieties. Based on this aqueous tandem reaction, a direct single-step multicomponent dual modification of peptide is developed from readily available starting materials. Furthermore, the method could also be applied to concise and fast multicomponent radioactive 125 I labeling from an aqueous solution of commercially available sodium 125 iodide as a starting material. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Recent Advances in Chemoenzymatic Peptide Syntheses

    Directory of Open Access Journals (Sweden)

    Kenjiro Yazawa

    2014-09-01

    Full Text Available Chemoenzymatic peptide synthesis is the hydrolase-catalyzed stereoselective formation of peptide bonds. It is a clean and mild procedure, unlike conventional chemical synthesis, which involves complicated and laborious protection-deprotection procedures and harsh reaction conditions. The chemoenzymatic approach has been utilized for several decades because determining the optimal conditions for conventional synthesis is often time-consuming. The synthesis of poly- and oligopeptides comprising various amino acids longer than a dipeptide continues to pose a challenge owing to the lack of knowledge about enzymatic mechanisms and owing to difficulty in optimizing the pH, temperature, and other reaction conditions. These drawbacks limit the applications of the chemoenzymatic approach. Recently, a variety of enzymes and substrates produced using recombinant techniques, substrate mimetics, and optimal reaction conditions (e.g., frozen aqueous media and ionic liquids have broadened the scope of chemoenzymatic peptide syntheses. In this review, we highlight the recent advances in the chemoenzymatic syntheses of various peptides and their use in developing new materials and biomedical applications.

  16. One Hundred Years of Peptide Chemistry*

    Indian Academy of Sciences (India)

    nated in the chemical synthesis of the oligopeptide hormone ... epoch-making event in the history of peptide chemistry. From .... These hormones raise the level of calcium concentration in blood by mobilizing calcium uptake from the bones. On the other hand, the thyroid hormone, calcitonin directs the flow of calcium ions in.

  17. Acetone-Linked Peptides: A Convergent Approach for Peptide Macrocyclization and Labeling.

    Science.gov (United States)

    Assem, Naila; Ferreira, David J; Wolan, Dennis W; Dawson, Philip E

    2015-07-20

    Macrocyclization is a broadly applied approach for overcoming the intrinsically disordered nature of linear peptides. Herein, it is shown that dichloroacetone (DCA) enhances helical secondary structures when introduced between peptide nucleophiles, such as thiols, to yield an acetone-linked bridge (ACE). Aside from stabilizing helical structures, the ketone moiety embedded in the linker can be modified with diverse molecular tags by oxime ligation. Insights into the structure of the tether were obtained through co-crystallization of a constrained S-peptide in complex with RNAse S. The scope of the acetone-linked peptides was further explored through the generation of N-terminus to side chain macrocycles and a new approach for generating fused macrocycles (bicycles). Together, these studies suggest that acetone linking is generally applicable to peptide macrocycles with a specific utility in the synthesis of stabilized helices that incorporate functional tags. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Contamination risks in work with synthetic peptides: flg22 as an example of a pirate in commercial peptide preparations.

    Science.gov (United States)

    Mueller, Katharina; Chinchilla, Delphine; Albert, Markus; Jehle, Anna K; Kalbacher, Hubert; Boller, Thomas; Felix, Georg

    2012-08-01

    The pattern recognition receptor FLAGELLIN SENSING2 (FLS2) renders plant cells responsive to subnanomolar concentrations of flg22, the active epitope of bacterial flagellin. We recently observed that a preparation of the peptide IDL1, a signal known to regulate abscission processes via the receptor kinases HAESA and HAESA-like2, apparently triggered Arabidopsis thaliana cells in an FLS2-dependent manner. However, closer investigation revealed that this activity was due to contamination by a flg22-type peptide, and newly synthesized IDL1 peptide was completely inactive in FLS2 signaling. This raised alert over contamination events occurring in the process of synthesis or handling of peptides. Two recent reports have suggested that FLS2 has further specificities for structurally unrelated peptides derived from CLV3 and from Ax21. We thus scrutinized these peptides for activity in Arabidopsis cells as well. While responding to peptides do occur and can be detected even in trace amounts by FLS2.

  19. Design, synthesis, and characterization of a 39 amino acid peptide mimic of the main immunogenic region of the Torpedo acetylcholine receptor.

    Science.gov (United States)

    Trinh, Vu B; Foster, Alex J; Fairclough, Robert H

    2014-05-01

    We have designed a 39 amino acid peptide mimic of the conformation-dependent main immunogenic region (MIR) of the Torpedo acetylcholine receptor (TAChR) that joins three discontinuous segments of the Torpedo α-subunit, α(1-12), α(65-79), and α(110 - 115) with two GS linkers: This 39MIR-mimic was expressed in E. coli as a fusion protein with an intein-chitin-binding domain (IChBD) to permit affinity collection on chitin beads. Six MIR-directed monoclonal antibodies (mAbs) bind to this complex and five agonist/antagonist site directed mAbs do not. The complex of MIR-directed mAb-132A with 39MIR has a Kd of (2.11±0.11)×10(-10)M, which is smaller than (7.13±1.20)×10(-10)M for the complex of mAb-132A with α(1-161) and about the same as 3.4×10(-10)M for that of mAb-132A with TAChR. Additionally, the 39MIR-IChBD adsorbs all MIR-directed antibodies (Abs) from an experimental autoimmune myasthenia gravis (EAMG) rat serum. Hence, the 39MIR-mimic has the potential to inactivate or remove pathogenic Torpedo MIR-directed Abs from EAMG sera and to direct a magic bullet to the memory B-cells that produce those pathogenic Abs. The hope is to use this as a guide to produce a mimic of the human MIR on the way to an antigen specific therapeutic agent to treat MG. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Flourescent Peptide-Stabilized Silver-Nanoclusters

    DEFF Research Database (Denmark)

    Gregersen, Simon

    throughput dramatically with regards to discovery of novel ligands. Our approach employs Fmoc solid-phase peptide synthesis on a PEGA resin which allows for on-resin screening of peptide ligands which, in turn, removes the tedious and labor-intensive work-up of synthesized peptides. The method allows for on......Fluorescent probes are widely used in the fields of imaging, detection, and diagnostics, and in order to achieve methodical progress, the search for new tools is an on-going quest. Within the last few decades, few-atom noble metal nanoclusters (NCs) have gathered increasing attention due....../reorganization of the peptide to facilitate NC formation. Following an initial chelation involving the thiol-functionality of cysteine side-chains, the coordination of silver into a defined NC is expected to be the driving force of the folding process. This work also illustrates the shortcomings of MALDI-TOF mass spectrometry...

  1. Human peptide transporters

    DEFF Research Database (Denmark)

    Nielsen, Carsten Uhd; Brodin, Birger; Jørgensen, Flemming Steen

    2002-01-01

    Peptide transporters are epithelial solute carriers. Their functional role has been characterised in the small intestine and proximal tubules, where they are involved in absorption of dietary peptides and peptide reabsorption, respectively. Currently, two peptide transporters, PepT1 and PepT2, wh...

  2. [SYNTHETIC PEPTIDE VACCINES].

    Science.gov (United States)

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested.

  3. Molecular tools for the construction of peptide-based materials.

    Science.gov (United States)

    Ramakers, B E I; van Hest, J C M; Löwik, D W P M

    2014-04-21

    Proteins and peptides are fundamental components of living systems where they play crucial roles at both functional and structural level. The versatile biological properties of these molecules make them interesting building blocks for the construction of bio-active and biocompatible materials. A variety of molecular tools can be used to fashion the peptides necessary for the assembly of these materials. In this tutorial review we shall describe five of the main techniques, namely solid phase peptide synthesis, native chemical ligation, Staudinger ligation, NCA polymerisation, and genetic engineering, that have been used to great effect for the construction of a host of peptide-based materials.

  4. Genome-based discovery, structure prediction and functional analysis of cyclic lipopeptide antibiotics in Pseudomonas species

    NARCIS (Netherlands)

    Bruijn, de I.; Kock, de M.J.D.; Meng, Y.; Waard, de P.; Beek, van T.A.; Raaijmakers, J.M.

    2007-01-01

    Analysis of microbial genome sequences have revealed numerous genes involved in antibiotic biosynthesis. In Pseudomonads, several gene clusters encoding non-ribosomal peptide synthetases (NRPSs) were predicted to be involved in the synthesis of cyclic lipopeptide (CLP) antibiotics. Most of these

  5. Production of cyanophycin in Rhizopus oryzae through the expression of a cyanophycin synthetase encoding gene

    NARCIS (Netherlands)

    Meussen, B.J.; Weusthuis, R.A.; Sanders, J.P.M.; Graaff, de L.H.

    2012-01-01

    Cyanophycin or cyanophycin granule peptide is a protein that results from non-ribosomal protein synthesis in microorganisms such as cyanobacteria. The amino acids in cyanophycin can be used as a feedstock in the production of a wide range of chemicals such as acrylonitrile, polyacrylic acid,

  6. Bioactive Peptides: Applications and Relevance for Cosmeceuticals

    Directory of Open Access Journals (Sweden)

    Tamyres Nassa Lima

    2018-03-01

    Full Text Available Peptides found in skin can act by different mechanisms of action, being able to function as epidermal or nervous growth factors or even as neurotransmitters. Due to the vast functionality of these compounds, there is growing research on bioactive peptides aimed at investigating their uses in products developed for stimulating collagen and elastin synthesis and improving skin healing. Thus, a literature search on applications of the most common bioactive peptides used in cosmeceuticals was carried out. There is a lack of proper reviews concerning this topic in scientific literature. Nine peptides with specific actions on body and facial dysfunctions were described. It could be noted while searching scientific literature that studies aimed at investigating peptides which prevent aging of the skin are overrepresented. This makes searching for peptides designed for treating other skin dysfunctions more difficult. The use of biomimetic peptides in cosmetic formulations aimed at attenuating or preventing different types of skin dysfunctions is a topic where information is still lackluster. Even though research on these compounds is relatively common, there is still a need for more studies concerning their practical uses so their mechanisms of action can be fully elucidated, as they tend to be quite complex.

  7. Biodiscovery of Aluminum Binding Peptides

    Science.gov (United States)

    2013-08-01

    et al., "Biomimetic synthesis and patterning of silver nanoparticles," Nat. Mater. 1(3), 169-172 (2002). [5] Van Dorst, B., et al., "Phage display...Biotechnol. 68(4), 505-509 (2005). [10] Lee, Y. J., et al., "Fabricating genetically engineered high-power lithium-ion batteries using multiple virus genes...34Sequestration of zinc oxide by fimbrial designer chelators," Appl. Environ. Microbiol. 66(1), 10-14 (2000). [26] Hnilova, M., et al., "Peptide-directed co

  8. Antimicrobial peptides in innate immune responses

    DEFF Research Database (Denmark)

    Sorensen, O.E.; Borregaard, N.; Cole, A.M.

    2008-01-01

    Antimicrobial peptides (AMPs) are ancient effector molecules in the innate immune response of eukaryotes. These peptides are important for the antimicrobial efficacy of phagocytes and for the innate immune response mounted by epithelia of humans and other mammals. AMPs are generated either by de...... novo synthesis or by proteolytic cleavage from antimicrobially inactive proproteins. Studies of human diseases and animal studies have given important clues to the in vivo role of AMPs. It is now evident that dysregulation of the generation of AMPs in innate immune responses plays a role in certain...

  9. Building parity between brand and generic peptide products: Regulatory and scientific considerations for quality of synthetic peptides.

    Science.gov (United States)

    Wu, Larisa C; Chen, Fu; Lee, Sau L; Raw, Andre; Yu, Lawrence X

    2017-02-25

    Peptides are a fast growing segment in the pharmaceutical industry. Consequently, the industry and regulatory agencies are increasing their focus on the regulatory path and quality considerations for peptide development and manufacturing. Although most peptides are synthetic, manufactured by solid phase synthesis, nevertheless they are complex molecules with challenging quality and regulatory aspects. This paper provides a structured overview of relevant quality issues for chemically synthesized peptides used as active pharmaceutical ingredients (API) in drug products. It addresses the unique characteristics of peptides pertaining to structural and physicochemical characterization, manufacturing and in process controls, impurities and aggregates arising from manufacturing and storage, along with their potential impact on safety (including immunogenicity) and efficacy of the peptide drug products. Published by Elsevier B.V.

  10. Synthesis and structural investigation of 2-aminomethyl-3-(4-methoxy-phenyl)-propionic acid containing a peptide analogue of the amyloidogenic AS(6-7) sequence: inhibition of fibril formation.

    Science.gov (United States)

    Paikar, Arpita; Debnath, Mintu; Podder, Debasish; Sasmal, Supriya; Haldar, Debasish

    2017-05-16

    The incorporation of a single β-amino acid moiety in a highly amyloidogenic peptide sequence resulted in the complete inhibition of amyloid fibril formation. The Boc-l-Phe-l-Leu-OMe sequence 1, which has sequence identity with the N-terminal AS(6-7) of the non-immunoglobulin amyloid fibril protein AS, which is responsible for rheumatoid arthritis, self-associates to produce fibrils. The d-Phe analogue peptide 2 shows an elongated ribbon-like morphology. However, the 2-aminomethyl-3-(4-methoxy-phenyl)-propionic acid containing analogue peptide 3 exhibits a polydisperse microsphere morphology. Moreover, fibrils from peptides 1 and 2 exhibit typical green-gold birefringence upon Congo red (CR) staining and show an amyloid-like morphological resemblance. However, the 2-aminomethyl-3-(4-methoxy-phenyl)-propionic acid modified peptide 3 does not respond to the Congo red assay. From X-ray crystallography, peptide 1 with the l-Phe residue adopts an extended structure, whereas the d-Phe analogue 2 adopts a kink-like structure. Both peptides 1 and 2 show twisted anti-parallel sheet-like structures at higher order assembly. However, peptide 3 adopts a nine-membered hydrogen bonded δ-turn-like structure in the solid state and self-associates to form a loop-like supramolecular structure through multiple intermolecular hydrogen bonds. The structural analysis presented herein may foster new studies for de novo design and therapeutics.

  11. Neurotensin enhances estradiol induced DNA synthesis in immature rat uterus

    Energy Technology Data Exchange (ETDEWEB)

    Mistry, A.; Vijayan, E.

    1985-05-27

    Systemic administration of Neurotensin, a tridecapeptide, in immature rats treated with estradiol benzoate significantly enhances uterine DNA synthesis as reflected by the incorporation of /sup 3/H-thymidine. The peptide may have a direct action on the uterus. Substance P, a related peptide, had no effect on uterine DNA synthesis. 18 references, 4 tables.

  12. Biosynthesis of the Peptide Antibiotic Feglymycin by a Linear Nonribosomal Peptide Synthetase Mechanism.

    Science.gov (United States)

    Gonsior, Melanie; Mühlenweg, Agnes; Tietzmann, Marcel; Rausch, Saskia; Poch, Annette; Süssmuth, Roderich D

    2015-12-01

    Feglymycin, a peptide antibiotic produced by Streptomyces sp. DSM 11171, consists mostly of nonproteinogenic phenylglycine-type amino acids. It possesses antibacterial activity against methicillin-resistant Staphylococcus aureus strains and antiviral activity against HIV. Inhibition of the early steps of bacterial peptidoglycan synthesis indicated a mode of action different from those of other peptide antibiotics. Here we describe the identification and assignment of the feglymycin (feg) biosynthesis gene cluster, which codes for a 13-module nonribosomal peptide synthetase (NRPS) system. Inactivation of an NRPS gene and supplementation of a hydroxymandelate oxidase mutant with the amino acid l-Hpg proved the identity of the feg cluster. Feeding of Hpg-related unnatural amino acids was not successful. This characterization of the feg cluster is an important step to understanding the biosynthesis of this potent antibacterial peptide. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A direct method for the synthesis of orthogonally protected furyl- and thienyl- amino acids.

    Science.gov (United States)

    Hudson, Alex S; Caron, Laurent; Colgin, Neil; Cobb, Steven L

    2015-04-01

    The synthesis of unnatural amino acids plays a key part in expanding the potential application of peptide-based drugs and in the total synthesis of peptide natural products. Herein, we report a direct method for the synthesis of orthogonally protected 5-membered heteroaromatic amino acids.

  14. PeptideAtlas

    Data.gov (United States)

    U.S. Department of Health & Human Services — PeptideAtlas is a multi-organism, publicly accessible compendium of peptides identified in a large set of tandem mass spectrometry proteomics experiments. Mass...

  15. Designer Natriuretic Peptides

    Science.gov (United States)

    Lee, Candace Y. W.; Lieu, Hsiao; Burnett, John C.

    2011-01-01

    Designer natriuretic peptides (NPs) are novel hybrid peptides that are engineered from the native NPs through addition, deletion, or substitution of amino acid(s) with a goal toward optimization of pharmacological actions while minimizing undesirable effects. In this article, selected peptides that were designed in our laboratory are reviewed, and future directions for research and development of designer NPs are discussed. PMID:19158603

  16. PH dependent adhesive peptides

    Science.gov (United States)

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  17. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  18. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    2015-01-01

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  19. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  20. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  1. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  2. Macrobrachium rosenbergii mannose binding lectin: synthesis of MrMBL-N20 and MrMBL-C16 peptides and their antimicrobial characterization, bioinformatics and relative gene expression analysis.

    Science.gov (United States)

    Arockiaraj, Jesu; Chaurasia, Mukesh Kumar; Kumaresan, Venkatesh; Palanisamy, Rajesh; Harikrishnan, Ramasamy; Pasupuleti, Mukesh; Kasi, Marimuthu

    2015-04-01

    Mannose-binding lectin (MBL), an antimicrobial protein, is an important component of innate immune system which recognizes repetitive sugar groups on the surface of bacteria and viruses leading to activation of the complement system. In this study, we reported a complete molecular characterization of cDNA encoded for MBL from freshwater prawn Macrobrachium rosenbergii (Mr). Two short peptides (MrMBL-N20: (20)AWNTYDYMKREHSLVKPYQG(39) and MrMBL-C16: (307)GGLFYVKHKEQQRKRF(322)) were synthesized from the MrMBL polypeptide. The purity of the MrMBL-N20 (89%) and MrMBL-C16 (93%) peptides were confirmed by MS analysis (MALDI-ToF). The purified peptides were used for further antimicrobial characterization including minimum inhibitory concentration (MIC) assay, kinetics of bactericidal efficiency and analysis of hemolytic capacity. The peptides exhibited antimicrobial activity towards all the Gram-negative bacteria taken for analysis, whereas they showed the activity towards only a few selected Gram-positive bacteria. MrMBL-C16 peptides produced the highest inhibition towards both the Gram-negative and Gram-positive bacteria compared to the MrMBL-N20. Both peptides do not produce any inhibition against Bacillus sps. The kinetics of bactericidal efficiency showed that the peptides drastically reduced the number of surviving bacterial colonies after 24 h incubation. The results of hemolytic activity showed that both peptides produced strong activity at higher concentration. However, MrMBL-C16 peptide produced the highest activity compared to the MrMBL-N20 peptide. Overall, the results indicated that the peptides can be used as bactericidal agents. The MrMBL protein sequence was characterized using various bioinformatics tools including phylogenetic analysis and structure prediction. We also reported the MrMBL gene expression pattern upon viral and bacterial infection in M. rosenbergii gills. It could be concluded that the prawn MBL may be one of the important molecule which

  3. Synthetic peptides derived from the sequence of a lasso peptide microcin J25 show antibacterial activity.

    Science.gov (United States)

    Soudy, Rania; Wang, Liru; Kaur, Kamaljit

    2012-03-01

    Microcin J25 (MccJ25) is a plasmid-encoded, ribosomally synthesized antibacterial peptide with a unique lasso structure. The lasso structure, produced with the aid of two processing enzymes, provides exceptional stability to MccJ25. We report the synthesis of six peptides (1-6), derived from the MccJ25 sequence, that are designed to form folded conformation by disulfide bond formation and electrostatic or hydrophobic interactions. Two peptides (1 and 6) display good activity against Salmonella newport, and are the first synthetic derivatives of MccJ25 that are bactericidal. Peptide 1 displays potent activity against several Salmonella strains including two MccJ25 resistant strains. The solution conformation and the stability studies of the active peptides suggest that they do not fold into a lasso conformation and peptide 1 displays antimicrobial activity by inhibition of target cell respiration. Like MccJ25, the synthetic MccJ25 derivatives display minimal toxicity to mammalian cells suggesting that these peptides act specifically on bacterial cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Peptide catalysed prebiotic polymerization of RNA

    DEFF Research Database (Denmark)

    Wieczorek, Rafal; Luisi, Pier Luigi; Monnard, Pierre-Alain

    A short peptide composed of only two amino acid residues, serine and histidine, is here reported to enable oligomerization of RNA monomers. SerHis dipeptide was previously reported to catalyse formation of peptide bonds (Gorlero et al. 2009) as well as possessing broad hydrolytic activities...... – in such environment hydrolysis is thermodynamically favoured over condensation. However, the thermodynamic equilibrium towards condensation can be shifted even in this environment. In this poster we describe a prebiotically plausible system in which the SerHis dipeptide acts as catalyst for the formation of RNA...... these conditions, most of the water is in the form of ice crystals and the other reactants are upconcentrated in the remaining liquid micro-inclusions, hence creating an environment with low water activity in which condensation reactions can occur. The ability of simple peptides to catalyse RNA synthesis could...

  5. Synthesis and Biological Evaluation of Cyclic [99mTc]-HYNIC-CGPRPPC as a Fibrin-Binding Peptide for Molecular Imaging of Thrombosis and Its Comparison with [99mTc]-HYNIC-GPRPP.

    Science.gov (United States)

    Rezaeianpour, Sedigheh; Bozorgi, Atefeh Hajiagha; Moghimi, Abolghasem; Almasi, Ameneh; Balalaie, Saeed; Ramezanpour, Sorour; Nasoohi, Sanaz; Mazidi, Seyed Mohammad; Geramifar, Parham; Bitarafan-Rajabi, Ahmad; Shahhosseini, Soraya

    2017-04-01

    Many patients worldwide suffer from cardiovascular diseases for which an underlying factor is thrombosis. Devising a molecular imaging technique for early detection of thrombosis in a clinical setting is highly recommended. Because fibrin is a major constituent of clots and is present in all types of thrombi but absent in circulation, it is a highly specific and sensitive target for molecular imaging of thrombi. It is assumed that cyclization of peptides will improve the receptor binding affinity and stability of the peptide. In the present study, we have developed linear and cyclic fibrin-binding peptides for thrombus imaging and compared their biological properties. Linear HYNIC-GPRPP and cyclic HYNIC-CGPRPPC peptides were synthesized using a standard Fmoc strategy and radiolabeled with Tc-99m. The stability of the radiolabeled peptides in human plasma and their affinity for fibrin and blood clots were determined. Blood clearance and biodistribution were evaluated in rats and mice, respectively. The peptide with the highest affinity was injected to a live rabbit femoral thrombosis model, and scintigraphic images were obtained. In vitro studies show that peptides are stable in human plasma and have a high affinity for human fibrin. They also demonstrated fast blood clearance in rats and high thrombus uptake in the Balb/c mice femoral thrombosis model. Femoral thrombosis was visualized 30 min postinjection of cyclic peptide in a live rabbit model using single photon emission computed tomography (SPECT)/X-ray computed tomography. The results indicate that the cyclic peptide is a promising agent for molecular imaging of fibrin using SPECT.

  6. Acylation of Therapeutic Peptides

    DEFF Research Database (Denmark)

    Trier, Sofie; Henriksen, Jonas Rosager; Jensen, Simon Bjerregaard

    to the harsh and selective gastrointestinal system, and development has lacked far behind injection therapy. Peptide acylation is a powerful tool to alter the pharmacokinetics, biophysical properties and chemical stability of injectable peptide drugs, primarily used to prolong blood circulation....... This work aims to characterize acylated analogues of two therapeutic peptides by systematically increasing acyl chain length in order to elucidate its influence on membrane interaction and intestinal cell translocation in vitro. The studied peptides are the 33 amino acid Glucagon-like peptide-2 (GLP-2...... peptides can increase in vitro intestinal permeability, modestly for GLP-2 and drastically for sCT, and might benefit oral delivery. GLP-2 results provide a well-founded predictive power for future peptide analogues, whereas sCT results hold great promise for future analogues, albeit with a larger...

  7. Chemically stabilized subtilisins in peptide synthesis

    OpenAIRE

    Colleary, Sandra; Ó Fágáin, Ciarán

    2008-01-01

    We have stabilized alcalaseTM and subtilisin Carlsberg (SC) against heat by chemical modification with ethylene glycol bis-succinimidyl succinate (EGNHS), a procedure not previously reported for subtilisins. The increases in thermal stability at 65oC were 1.8-fold and 4.7-fold respectively. Caseinolytic activity of alcalase in aqueous buffer was unchanged following modification but apparent Km of SC decreased 2.5-fold. Native and modified forms of both enzymes synthesized the tripeptide Z-...

  8. Synthesis of cyclic alpha-MSH peptides

    NARCIS (Netherlands)

    Schaaper, W.M.M.; Adan, R.A.H.; Posthuma, T.A.; Oosterom, J.; Gispen, W.H.; Meloen, R.H.

    1998-01-01

    Cyclic lactam analogs of α-melanocyte stimulating hormone (α-MSH) have been shown to be potent agonists in the frog skin bioassay [Al-Obeidi, F. et al., J. Med. Chem., 32 (1989) 2555], demonstrating melanocortin-1 (MC1) receptor activity. We synthesized cyclic α-MSH(1-13) and α-MSH(4-10) lactam

  9. Synthesis of cyclic α-MSH peptides

    NARCIS (Netherlands)

    Gispen, W.H.; Schaaper, W.M.M..; Adan, R.A.H.; Posthuma, T.A.; Oosterom, J.; Meloen, R.H.

    1998-01-01

    Cyclic lactam analogs of -melanocyte stimulating hormone (-MSH) have been shown to be potent agonists in the frog skin bioassay [Al-Obeidi, F. et al., J. Med. Chem., 32 (1989) 2555], demonstrating melanocortin-1 (MC1) receptor activity. We synthesized cyclic -MSH(1-13) and -MSH(4-10) lactam analogs.

  10. Cell Penetrating Peptides and Cationic Antibacterial Peptides

    Science.gov (United States)

    Rodriguez Plaza, Jonathan G.; Morales-Nava, Rosmarbel; Diener, Christian; Schreiber, Gabriele; Gonzalez, Zyanya D.; Lara Ortiz, Maria Teresa; Ortega Blake, Ivan; Pantoja, Omar; Volkmer, Rudolf; Klipp, Edda; Herrmann, Andreas; Del Rio, Gabriel

    2014-01-01

    Cell penetrating peptides (CPP) and cationic antibacterial peptides (CAP) have similar physicochemical properties and yet it is not understood how such similar peptides display different activities. To address this question, we used Iztli peptide 1 (IP-1) because it has both CPP and CAP activities. Combining experimental and computational modeling of the internalization of IP-1, we show it is not internalized by receptor-mediated endocytosis, yet it permeates into many different cell types, including fungi and human cells. We also show that IP-1 makes pores in the presence of high electrical potential at the membrane, such as those found in bacteria and mitochondria. These results provide the basis to understand the functional redundancy of CPPs and CAPs. PMID:24706763

  11. Selection of peptides for serological detection of equine infectious anemia.

    Science.gov (United States)

    Santos, E M; Cardoso, R; Souza, G R L; Goulart, L R; Heinemann, M B; Leite, R C; Reis, J K P

    2012-08-13

    Equine infectious anemia caused by equine infectious anemia virus is an important disease due to its high severity and incidence in animals. We used a phage display library to isolate peptides that can be considered potential markers for equine infectious anemia diagnosis. We selected peptides using IgG purified from a pool comprised of 20 sera from animals naturally infected with equine infectious anemia virus. The diagnostic potential of these peptides was investigated by ELISA, Western blot and dot blot with purified IgG and serum samples. Based on the results, we chose a peptide mimetic for glycoprotein gp45 epitopes of equine infectious anemia virus, with potential for use as an antigen in indirect diagnostic assays. Synthesis of this peptide has possible applications for the development of new diagnostic tools for this disease.

  12. Bioprinting synthetic self-assembling peptide hydrogels for biomedical applications

    International Nuclear Information System (INIS)

    Loo, Yihua; Hauser, Charlotte A E

    2016-01-01

    Three-dimensional (3D) bioprinting is a disruptive technology for creating organotypic constructs for high-throughput screening and regenerative medicine. One major challenge is the lack of suitable bioinks. Short synthetic self-assembling peptides are ideal candidates. Several classes of peptides self-assemble into nanofibrous hydrogels resembling the native extracellular matrix. This is a conducive microenvironment for maintaining cell survival and physiological function. Many peptides also demonstrate stimuli-responsive gelation and tuneable mechanical properties, which facilitates extrusion before dispensing and maintains the shape fidelity of the printed construct in aqueous media. The inherent biocompatibility and biodegradability bodes well for in vivo applications as implantable tissues and drug delivery matrices, while their short length and ease of functionalization facilitates synthesis and customization. By applying self-assembling peptide inks to bioprinting, the dynamic complexity of biological tissue can be recreated, thereby advancing current biomedical applications of peptide hydrogel scaffolds. (paper)

  13. Plant peptide hormone signalling.

    Science.gov (United States)

    Motomitsu, Ayane; Sawa, Shinichiro; Ishida, Takashi

    2015-01-01

    The ligand-receptor-based cell-to-cell communication system is one of the most important molecular bases for the establishment of complex multicellular organisms. Plants have evolved highly complex intercellular communication systems. Historical studies have identified several molecules, designated phytohormones, that function in these processes. Recent advances in molecular biological analyses have identified phytohormone receptors and signalling mediators, and have led to the discovery of numerous peptide-based signalling molecules. Subsequent analyses have revealed the involvement in and contribution of these peptides to multiple aspects of the plant life cycle, including development and environmental responses, similar to the functions of canonical phytohormones. On the basis of this knowledge, the view that these peptide hormones are pivotal regulators in plants is becoming increasingly accepted. Peptide hormones are transcribed from the genome and translated into peptides. However, these peptides generally undergo further post-translational modifications to enable them to exert their function. Peptide hormones are expressed in and secreted from specific cells or tissues. Apoplastic peptides are perceived by specialized receptors that are located at the surface of target cells. Peptide hormone-receptor complexes activate intracellular signalling through downstream molecules, including kinases and transcription factors, which then trigger cellular events. In this chapter we provide a comprehensive summary of the biological functions of peptide hormones, focusing on how they mature and the ways in which they modulate plant functions. © 2015 Authors; published by Portland Press Limited.

  14. Catalytic Oligopeptide Synthesis.

    Science.gov (United States)

    Liu, Zijian; Noda, Hidetoshi; Shibasaki, Masakatsu; Kumagai, Naoya

    2018-02-02

    Waste-free catalytic assembly of α-amino acids is fueled by a multiboron catalyst that features a characteristic B 3 NO 2 heterocycle, providing a versatile catalytic protocol wherein functionalized natural α-amino acid units are accommodated and commonly used protecting groups are tolerated. The facile dehydrative conditions eliminate the use of engineered peptide coupling reagents, exemplifying a greener catalytic alternative for peptide coupling. The catalysis is sufficiently robust to enable pentapeptide synthesis, constructing all four amide bond linkages in a catalytic fashion.

  15. Putative Nonribosomal Peptide Synthetase and Cytochrome P450 Genes Responsible for Tentoxin Biosynthesis in Alternaria alternata ZJ33.

    Science.gov (United States)

    Li, You-Hai; Han, Wen-Jin; Gui, Xi-Wu; Wei, Tao; Tang, Shuang-Yan; Jin, Jian-Ming

    2016-08-02

    Tentoxin, a cyclic tetrapeptide produced by several Alternaria species, inhibits the F₁-ATPase activity of chloroplasts, resulting in chlorosis in sensitive plants. In this study, we report two clustered genes, encoding a putative non-ribosome peptide synthetase (NRPS) TES and a cytochrome P450 protein TES1, that are required for tentoxin biosynthesis in Alternaria alternata strain ZJ33, which was isolated from blighted leaves of Eupatorium adenophorum. Using a pair of primers designed according to the consensus sequences of the adenylation domain of NRPSs, two fragments containing putative adenylation domains were amplified from A. alternata ZJ33, and subsequent PCR analyses demonstrated that these fragments belonged to the same NRPS coding sequence. With no introns, TES consists of a single 15,486 base pair open reading frame encoding a predicted 5161 amino acid protein. Meanwhile, the TES1 gene is predicted to contain five introns and encode a 506 amino acid protein. The TES protein is predicted to be comprised of four peptide synthase modules with two additional N-methylation domains, and the number and arrangement of the modules in TES were consistent with the number and arrangement of the amino acid residues of tentoxin, respectively. Notably, both TES and TES1 null mutants generated via homologous recombination failed to produce tentoxin. This study provides the first evidence concerning the biosynthesis of tentoxin in A. alternata.

  16. Targeted Disruption of Nonribosomal Peptide Synthetase pes3 Augments the Virulence of Aspergillus fumigatus

    DEFF Research Database (Denmark)

    O'Hanlon, Karen A.; Cairns, Timothy; Stack, Deirdre

    2011-01-01

    Nonribosomal peptide synthesis (NRPS) is a documented virulence factor for the opportunistic pathogen Aspergillus fumigatus and other fungi. Secreted or intracellularly located NRP products include the toxic molecule gliotoxin and the iron-chelating siderophores triacetylfusarinine C and ferricro...

  17. Novel Peptide/Protein Delivery System Targeting erbB2-Overexpressing Breast Cancer Cells

    National Research Council Canada - National Science Library

    Yu, Dihua

    2002-01-01

    .... During this funding year, we focused on the delivery of erbB2 signal-blocking ESP peptides (objective 2) . Because of the complexity of biotin-penetratin-AHNP-ESP, the synthesis was unsuccessful...

  18. Cyclic Sulfamidate Enabled Syntheses of Amino Acids, Peptides, Carbohydrates, and Natural Products

    Science.gov (United States)

    This article reviews the emergence of cyclic sulfamidates as versatile intermediatesfor the synthesis of unnatural amino acids, chalcogen peptides, modified sugars, drugs and drug candidates, and important natural products.

  19. Peptide welding technology - A simple strategy for generating innovative ligands for G protein coupled receptors.

    Science.gov (United States)

    Calo', Girolamo; Rizzi, Anna; Ruzza, Chiara; Ferrari, Federica; Pacifico, Salvatore; Gavioli, Elaine C; Salvadori, Severo; Guerrini, Remo

    2018-01-01

    Based on their high selectivity of action and low toxicity, naturally occurring peptides have great potential in terms of drug development. However, the pharmacokinetic properties of peptides, in particular their half life, are poor. Among different strategies developed for reducing susceptibility to peptidases, and thus increasing the duration of action of peptides, the generation of branched peptides has been described. However, the synthesis and purification of branched peptides are extremely complicated thus limiting their druggability. Here we present a novel and facile synthesis of tetrabranched peptides acting as GPCR ligands and their in vitro and vivo pharmacological characterization. Tetrabranched derivatives of nociceptin/orphanin FQ (N/OFQ), N/OFQ related peptides, opioid peptides, tachykinins, and neuropeptide S were generated with the strategy named peptide welding technology (PWT) and characterized by high yield and purity of the desired final product. In general, PWT derivatives displayed a pharmacological profile similar to that of the natural sequence in terms of affinity, pharmacological activity, potency, and selectivity of action in vitro. More importantly, in vivo studies demonstrated that PWT peptides are characterized by increased potency associated with long lasting duration of action. In conclusion, PWT derivatives of biologically active peptides can be viewed as innovative pharmacological tools for investigating those conditions and states in which selective and prolonged receptor stimulation promotes beneficial effects. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Antimicrobial Peptides in Reptiles

    Science.gov (United States)

    van Hoek, Monique L.

    2014-01-01

    Reptiles are among the oldest known amniotes and are highly diverse in their morphology and ecological niches. These animals have an evolutionarily ancient innate-immune system that is of great interest to scientists trying to identify new and useful antimicrobial peptides. Significant work in the last decade in the fields of biochemistry, proteomics and genomics has begun to reveal the complexity of reptilian antimicrobial peptides. Here, the current knowledge about antimicrobial peptides in reptiles is reviewed, with specific examples in each of the four orders: Testudines (turtles and tortosises), Sphenodontia (tuataras), Squamata (snakes and lizards), and Crocodilia (crocodilans). Examples are presented of the major classes of antimicrobial peptides expressed by reptiles including defensins, cathelicidins, liver-expressed peptides (hepcidin and LEAP-2), lysozyme, crotamine, and others. Some of these peptides have been identified and tested for their antibacterial or antiviral activity; others are only predicted as possible genes from genomic sequencing. Bioinformatic analysis of the reptile genomes is presented, revealing many predicted candidate antimicrobial peptides genes across this diverse class. The study of how these ancient creatures use antimicrobial peptides within their innate immune systems may reveal new understandings of our mammalian innate immune system and may also provide new and powerful antimicrobial peptides as scaffolds for potential therapeutic development. PMID:24918867

  1. Comparative structural studies of potent neuroprotective peptides of the Humanin family

    Czech Academy of Sciences Publication Activity Database

    Benaki, D.; Zikos, C.; Evangelou, A.; Slaninová, Jiřina; Vlassi, M.; Livaniou, E.; Mikros, E.; Pelecanou, M.

    2008-01-01

    Roč. 14, č. 8 (2008), s. 108-108 ISSN 1075-2617. [European Peptide Symposium /30./. 31.08.2008-05.09.2008, Helsinki] Institutional research plan: CEZ:AV0Z40550506 Keywords : neuroprotective peptides * analogues of humanin e * synthesis * activity Subject RIV: CC - Organic Chemistry

  2. Alum an Efficient Catalyst for Erlenmeyer Synthesis

    African Journals Online (AJOL)

    NICO

    found to be useful precursors for the synthesis of amino acids,2 peptides,3 and ... tuted imidazoles,21h etc. However, there are no examples of the use of alum as a catalyst for the synthesis of azlactone deriva- tives. 2. Result and Discussion .... 12 P.S. Rao and R.V. Venkataratnam, Indian J. Chem, 1994, 33B, 984–985.

  3. Amino acids attached to 2'-amino-LNA: Synthesis of DNA mixmer oligonucleotides with increased duplex stability

    DEFF Research Database (Denmark)

    Johannsen, Marie Willaing; Wengel, Jesper; Wamberg, Michael Chr.

    2010-01-01

    -LNA nucleosides derivatized with amino acids have been synthesized and incorporated into DNA oligonucleotides. Following oligonucleotide synthesis, peptides have been added using solid phase peptide coupling chem. Modification of oligonucleotides with pos. charged residues greatly improves thermal stability....

  4. Insulin C-peptide test

    Science.gov (United States)

    C-peptide ... the test depends on the reason for the C-peptide measurement. Ask your health care provider if ... C-peptide is measured to tell the difference between insulin the body produces and insulin someone injects ...

  5. O-acyl isopeptide method: development of an O-acyl isodipeptide unit for Boc SPPS and its application to the synthesis of Aβ1-42 isopeptide.

    Science.gov (United States)

    Yoshiya, Taku; Uemura, Tsuyoshi; Maruno, Takahiro; Kubo, Shigeru; Kiso, Yoshiaki; Sohma, Youhei; Kobayashi, Yuji; Yoshizawa-Kumagaye, Kumiko; Nishiuchi, Yuji

    2014-09-01

    The O-acyl isopeptide method was developed for the efficient preparation of difficult sequence-containing peptide. Furthermore, development of the O-acyl isodipeptide unit for Fmoc chemistry simplified its synthetic procedure by solid-phase peptide synthesis. Here, we report a novel isodipeptide unit for Boc chemistry, and the unit was successfully applied to the synthesis of amyloid β peptide. Combination of Boc chemistry and the isodipeptide unit would be an effective method for the synthesis of many difficult peptides. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  6. Use of tritium labeled compounds in peptide chemistry. Part 3. Influence of structure of peptide coupling amino acids on the extent of racemization

    International Nuclear Information System (INIS)

    Kolodziejczyk, A.M.; Arendt, A.

    1979-01-01

    A modified radiochromatographic method has been used to determine the degree of racemization in synthesis reactions of 12 peptides varying in amino acid composition and kind of protection. The degree of racemization in these reactions was not only found to depend on the kind of protection of the acylating amino acid and the reaction conditions as, e.g., the kind of method used in the synthesis, but also, and to a high degree, on the structure of amino acids, both acylating and acylated, concerned with the coupling stage in peptide synthesis. (author)

  7. BIOACTIVE PEPTIDES OF THE COW MILK WHEY PROTEINS (Bos taurus

    Directory of Open Access Journals (Sweden)

    A. V. Iukalo

    2013-10-01

    Full Text Available Data on the biological functions of milk whey proteins, which are implemented at the level of their proteolytic degradation products — bioactive peptides have been reviewed. The main functions of these proteins is to provide the amino acid nutrition of mammals in the early stages of development, as well as the transport of fatty acids, retinol, involved in the synthesis of lactose, ions of calcium and iron, immune protection, antimicrobial action, etc. However, in recent years, it has been found that milk proteins like casein are precursors of biologically active peptides. Аngiotensin — converting enzyme, opioid peptides which are opiate receptor agonists, anti–microbial peptides, peptides with immunomodulatory and hypocholesterolemic action, and peptides affecting motility have been found among the products of proteolytic degradation of ?-lactoglobulin, ?-laktoalbumin, lactoferrin and milk whey albumin. Also data on the possible participation of peptides from milk whey proteins in the implementation of the biological functions of both the assimilation of calcium, antioxidant effect, the regulation of appetite, anticarcinogenic are provided. The authors assume that the phenomenon of bioactive peptides formation could be considered as an additional function of natural food proteins, which gives advantages to the mammals and has a positive effect on their development in the postnatal period. Ways of bioactive peptides formation, their resistance to action of proteolytic enzymes, the ability to cross into the bloodstream and have biological effects have been also discussed. Up to date, only a few products with bioactive peptides from milk whey proteins are obtained. Further studies of their structure, mechanism of action, ways of formation and methods of isolation are required for their wider use. Formation of functional products based on bioactive peptides from milk whey proteins will allow efficient use of milk whey, which is often a

  8.  Pleiotropic action of proinsulin C-peptid

    Directory of Open Access Journals (Sweden)

    Michał Usarek

    2012-03-01

    Full Text Available  Proinsulin C-peptide, released in equimolar amounts with insulin by pancreatic β cells, since its discovery in 1967 has been thought to be devoid of biological functions apart from correct insulin processing and formation of disulfide bonds between A and B chains. However, in the last two decades research has brought a substantial amount of data indicating a crucial role of C-peptide in regulating various processes in different types of cells and organs. C-peptide acts presumably via either G-protein-coupled receptor or directly inside the cell, after being internalized. However, a receptor binding this peptide has not been identified yet. This peptide ameliorates pathological changes induced by type 1 diabetes mellitus, including glomerular hyperfiltration, vessel endothelium inflammation and neuron demyelinization. In diabetic patients and diabetic animal models, C-peptide substitution in physiological doses improves the functional and structural properties of peripheral neurons and protects against hyperglycemia-induced apoptosis, promoting neuronal development, regeneration and cell survival. Moreover, it affects glycogen synthesis in skeletal muscles. In vitro C-peptide promotes disaggregation of insulin oligomers, thus enhancing its bioavailability and effects on metabolism. There are controversies concerning the biological action of C-peptide, particularly with respect to its effect on Na /K -ATPase activity. Surprisingly, the excess of circulating peptide associated with diabetes type 2 contributes to atherosclerosis development. In view of these observations, long-term, large-scale clinical investigations using C-peptide physiological doses need to be conducted in order to determine safety and health outcomes of long-term administration of C-peptide to diabetic patients.

  9. Quinacrine reactivity with prion proteins and prion-derived peptides

    Czech Academy of Sciences Publication Activity Database

    Zawada, Zbigniew; Šafařík, Martin; Dvořáková, E.; Janoušková, O.; Březinová, Anna; Stibor, Ivan; Holada, K.; Bouř, Petr; Hlaváček, Jan; Šebestík, Jaroslav

    2013-01-01

    Roč. 44, č. 5 (2013), s. 1279-1292 ISSN 0939-4451 R&D Projects: GA ČR GA203/07/1517 Institutional support: RVO:61388963 Keywords : quinacrine * prion protein and peptide model reactions * solid phase and recombinant synthesis Subject RIV: CE - Biochemistry Impact factor: 3.653, year: 2013

  10. New small-size peptides possessing antifungal activity

    NARCIS (Netherlands)

    Garibotto, Francisco M.; Garro, Adriana D.; Masman, Marcelo F.; Rodriguez, Ana M.; Luiten, Paul G. M.; Raimondi, Marcela; Zacchino, Susana A.; Somlai, Csaba; Penke, Botond; Enriz, Ricardo D.

    2010-01-01

    The synthesis, in vitro evaluation, and conformational study of a new series of small-size peptides acting as antifungal agents are reported. In a first step of our study we performed a conformational analysis using Molecular Mechanics calculations. The electronic study was carried out using

  11. Antimicrobial peptides as natural bio-preservative to enhance the shelf-life of food.

    Science.gov (United States)

    Rai, Mahendra; Pandit, Raksha; Gaikwad, Swapnil; Kövics, György

    2016-09-01

    Antimicrobial peptides (AMPs) are diverse group of natural proteins present in animals, plants, insects and bacteria. These peptides are responsible for defense of host from pathogenic organisms. Chemical, enzymatic and recombinant techniques are used for the synthesis of antimicrobial peptides. These peptides have been found to be an alternative to the chemical preservatives. Currently, nisin is the only antimicrobial peptide, which is widely utilized in the preservation of food. Antimicrobial peptides can be used alone or in combination with other antimicrobial, essential oils and polymeric nanoparticles to enhance the shelf-life of food. This review presents an overview on different types of antimicrobial peptides, purification techniques, mode of action and application in food preservation.

  12. Stereoselective synthesis of macrocyclic peptides via a dual olefin metathesis and ethenolysis approach† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc01507c Click here for additional data file.

    Science.gov (United States)

    Mangold, Shane L.

    2015-01-01

    Macrocyclic compounds occupy an important chemical space between small molecules and biologics and are prevalent in many natural products and pharmaceuticals. The growing interest in macrocycles has been fueled, in part, by the design of novel synthetic methods to these compounds. One appealing strategy is ring-closing metathesis (RCM) that seeks to construct macrocycles from acyclic diene precursors using defined transition-metal alkylidene catalysts. Despite its broad utility, RCM generally gives rise to a mixture of E- and Z-olefin isomers that can hinder efforts for the large-scale production and isolation of such complex molecules. To address this issue, we aimed to develop methods that can selectively enrich macrocycles in E- or Z-olefin isomers using an RCM/ethenolysis strategy. The utility of this methodology was demonstrated in the stereoselective formation of macrocyclic peptides, a class of compounds that have gained prominence as therapeutics in drug discovery. Herein, we report an assessment of various factors that promote catalyst-directed RCM and ethenolysis on a variety of peptide substrates by varying the olefin type, peptide sequence, and placement of the olefin in macrocycle formation. These methods allow for control over olefin geometry in peptides, facilitating their isolation and characterization. The studies outlined in this report seek to expand the scope of stereoselective olefin metathesis in general RCM. PMID:26509000

  13. Synthesis of C-linked carbo-β2-amino acids and β2-peptides: design of new motifs for left-handed 12/10- and 10/12-mixed helices.

    Science.gov (United States)

    Sharma, Gangavaram V M; Reddy, Nelli Yella; Ravi, Rapolu; Sreenivas, Bommagani; Sridhar, Gattu; Chatterjee, Deepak; Kunwar, Ajit C; Hofmann, Hans-Jörg

    2012-12-14

    C-linked carbo-β(2)-amino acids (β(2)-Caa), a new class of β-amino acid with a carbohydrate side chain having d-xylo configuration, were prepared from d-glucose. The main idea behind the design of the new β-amino acids was to move the steric strain of the bulky carbohydrate side chain from the Cβ- to the Cα-carbon atom and to explore its influence on the folding propensities in peptides with alternating (R)- and (S)-β(2)-Caas. The tetra- and hexapeptides derived were studied employing NMR (in CDCl(3)), CD, and molecular dynamics simulations. The β(2)-peptides of the present study form left-handed 12/10- and 10/12-mixed helices independent of the order of the alternating chiral amino acids in the sequence and result in a new motif. These results differ from earlier findings on β(3)-peptides of the same design, containing a carbohydrate side chain with d-xylo configuration, which form exclusively right-handed 12/10-mixed helices. Quantum chemical calculations employing ab initio MO theory suggest the side chain chirality as an important factor for the observed definite left- or right-handedness of the helices in the β(2)- and β(3)-peptides.

  14. Peptide-templated noble metal catalysts: syntheses and applications.

    Science.gov (United States)

    Wang, Wei; Anderson, Caleb F; Wang, Zongyuan; Wu, Wei; Cui, Honggang; Liu, Chang-Jun

    2017-05-01

    Noble metal catalysts have been widely used in many applications because of their high activity and selectivity. However, a controllable preparation of noble metal catalysts still remains as a significant challenge. To overcome this challenge, peptide templates can play a critical role in the controllable syntheses of catalysts owing to their flexible binding with specific metallic surfaces and self-assembly characteristics. By employing peptide templates, the size, shape, facet, structure, and composition of obtained catalysts can all be specifically controlled under the mild synthesis conditions. In addition, catalysts with spherical, nanofiber, and nanofilm structures can all be produced by associating with the self-assembly characteristics of peptide templates. Furthermore, the peptide-templated noble metal catalysts also reveal significantly enhanced catalytic behaviours compared with conventional catalysts because the electron conductivity, metal dispersion, and reactive site exposure can all be improved. In this review, we summarize the research progresses in the syntheses of peptide-templated noble metal catalysts. The applications of the peptide-templated catalysts in organic reactions, photocatalysis, and electrocatalysis are discussed, and the relationship between structure and activity of these catalysts are addressed. Future opportunities, including new catalytic materials designed by using biological principles, are indicated to achieve selective, eco-friendly, and energy neutral synthesis approaches.

  15. Dual effect of chloramphenicol peptides on ribosome inhibition.

    Science.gov (United States)

    Bougas, Anthony; Vlachogiannis, Ioannis A; Gatos, Dimitrios; Arenz, Stefan; Dinos, George P

    2017-05-01

    Chloramphenicol peptides were recently established as useful tools for probing nascent polypeptide chain interaction with the ribosome, either biochemically, or structurally. Here, we present a new 10mer chloramphenicol peptide, which exerts a dual inhibition effect on the ribosome function affecting two distinct areas of the ribosome, namely the peptidyl transferase center and the polypeptide exit tunnel. According to our data, the chloramphenicol peptide bound on the chloramphenicol binding site inhibits the formation of both acetyl-phenylalanine-puromycin and acetyl-lysine-puromycin, showing, however, a decreased peptidyl transferase inhibition compared to chloramphenicol-mediated inhibition per se. Additionally, we found that the same compound is a strong inhibitor of green fluorescent protein synthesis in a coupled in vitro transcription-translation assay as well as a potent inhibitor of lysine polymerization in a poly(A)-programmed ribosome, showing that an additional inhibitory effect may exist. Since chemical protection data supported the interaction of the antibiotic with bases A2058 and A2059 near the entrance of the tunnel, we concluded that the extra inhibition effect on the synthesis of longer peptides is coming from interactions of the peptide moiety of the drug with residues comprising the ribosomal tunnel, and by filling up the tunnel and blocking nascent chain progression through the restricted tunnel. Therefore, the dual interaction of the chloramphenicol peptide with the ribosome increases its inhibitory effect and opens a new window for improving the antimicrobial potency of classical antibiotics or designing new ones.

  16. Synthetic Advances in Insulin-like Peptides Enable Novel Bioactivity.

    Science.gov (United States)

    Liu, Fa; Li, Pengyun; Gelfanov, Vasily; Mayer, John; DiMarchi, Richard

    2017-08-15

    Insulin is a miraculous hormone that has served a seminal role in the treatment of insulin-dependent diabetes for nearly a century. Insulin resides within in a superfamily of structurally related peptides that are distinguished by three invariant disulfide bonds that anchor the three-dimensional conformation of the hormone. The additional family members include the insulin-like growth factors (IGF) and the relaxin-related set of peptides that includes the so-called insulin-like peptides. Advances in peptide chemistry and rDNA-based synthesis have enabled the preparation of multiple insulin analogues. The translation of these methods from insulin to related peptides has presented unique challenges that pertain to differing biophysical properties and unique amino acid compositions. This Account presents a historical context for the advances in the chemical synthesis of insulin and the related peptides, with division into two general categories where disulfide bond formation is facilitated by native conformational folding or alternatively orthogonal chemical reactivity. The inherent differences in biophysical properties of insulin-like peptides, and in particular within synthetic intermediates, have constituted a central limitation to achieving high yield synthesis of properly folded peptides. Various synthetic approaches have been advanced in the past decade to successfully address this challenge. The use of chemical ligation and metastable amide bond surrogates are two of the more important synthetic advances in the preparation of high quality synthetic precursors to high potency peptides. The discovery and application of biomimetic connecting peptides simplifies proper disulfide formation and the subsequent traceless removal by chemical methods dramatically simplifies the total synthesis of virtually any two-chain insulin-like peptide. We report the application of these higher synthetic yield methodologies to the preparation of insulin-like peptides in support of

  17. Synthesis of Glucose Spiropiperazinone Derivatives

    OpenAIRE

    Vasiļjevs, D

    2013-01-01

    Piperazinone derivatives аге noticeable peptidometics; therefore, they сап replace peptides, such as RGD and Leu-enkephalin in different biological processes. Some piperazinone derivatives are anticoagulants, others act like neurotransmitters. Herein, we report an approach for the synthesis of поуеl piperazinone ring containing spiro-derivatives of glucose.

  18. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    Introduction: A frightening increase in the number of isolated multidrug resistant bacterial strains linked to the decline in novel antimicrobial drugs entering the market is a great cause for concern. Cationic antimicrobial peptides (AMPs) have lately been introduced as a potential new class...... of antimicrobial drugs, and computational methods utilizing molecular descriptors can significantly accelerate the development of new peptide drug candidates. Areas covered: This paper gives a broad overview of peptide and amino-acid scale descriptors available for AMP modeling and highlights which...

  19. Peptides as catalysts in the RNA world

    DEFF Research Database (Denmark)

    Wieczorek, Rafal; Dörr, Mark; Luisi, Pier Luigi

    The emergence of RNA chains from prebiotic soup is considered a stumbling block in the RNA world theory (Orgel 2004). Both the activation of RNA monomers and their subsequent oligomerization is hard to achieve in accepted early Earth conditions, thus putting doubt on the prebiotic plausibility...... of the RNA world concept. Contrary to RNA building blocks, amino acids form quite easily in simulated prebiotic reactions. Also, many prebiotic scenarios for condensation of amino acids into peptides have been proposed and successfully demonstrated experimentally (Rode 1999). We also have growing body...... was sequestered into ice crystals and the other reactants were up-concentrated in the remaining liquid microinclusions, thus creating an environment with low water activity in which condensation reactions can occur. The ability of simple peptides to catalyze RNA synthesis could represent a link between prebiotic...

  20. Novel peptide-based protease inhibitors

    DEFF Research Database (Denmark)

    Roodbeen, Renée

    This thesis describes the design and synthesis of peptide-based serine protease inhibitors. The targeted protease, urokinase-type plasminogen activator (uPA) activates plasminogen, which plays a major role in cancer metastasis. The peptide upain-2 (S 1 ,S 12-cyclo-AcCSWRGLENHAAC-NH2) is a highly...... specific inhibitor of uPA. With the aim of creating better inhibitors based on the upain-2 scaffold, the following three strategies were explored: First, it was attempted to predefine the structure of upain-2 in solution by incorporating turn-inducing sequences and peptidomimetics. Additionally...... bond across the ring. The second bridge was made by a disulfide bridge, amide bond formation or via ring-closing metathesis. A, with upain-2 equipotent, bicyclic inhibitor was obtained and its binding to uPA was studied by ITC, NMR and X-ray. The knowledge of how selective inhibitors bind uPA has been...

  1. Tumor penetrating peptides

    Directory of Open Access Journals (Sweden)

    Tambet eTeesalu

    2013-08-01

    Full Text Available Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC, contains the integrin-binding RGD motif. RGD mediates tumor homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular zip code of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is

  2. Tumor-Penetrating Peptides

    Science.gov (United States)

    Teesalu, Tambet; Sugahara, Kazuki N.; Ruoslahti, Erkki

    2013-01-01

    Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC), contains the integrin-binding RGD motif. RGD mediates tumor-homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR) motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular “zip code” of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies, and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is present in the

  3. Novel Endogenous Antimicrobial Peptides

    OpenAIRE

    Nordahl, Emma

    2009-01-01

    Antimicrobial peptides serve as a first line of defence against invading microorganisms and are an essential part of our fast innate immune system. They are ancient molecules found in all classes of life. Antimicrobial peptides rapidly kill a broad spectrum of microbes and are immunomodulatory, i.e. having additional actions influencing inflammation and other innate immune responses. Results presented in this thesis demonstrate that proteases of common human pathogens degrade and inactivate t...

  4. Serine/threonine ligation for the chemical synthesis of proteins.

    Science.gov (United States)

    Lee, Chi Lung; Li, Xuechen

    2014-10-01

    Advances in the development of efficient peptide ligation methods have enabled the total synthesis of complex proteins to be successfully undertaken. Recently, a Ser/Thr ligation has emerged as a new tool in synthetic protein chemistry. The chemoselective reaction between an N-terminal serine or threonine of an unprotected peptide segment and a C-terminal salicylaldehyde ester of another unprotected peptide segment gives rise to an N,O-benzylidene acetal linked product, which upon acidolysis produces a native peptide bond at the site of ligation. Ser/Thr ligation has been used for the synthesis of the human erythrocyte acylphosphatase protein and MUC1 glycopeptide segments, semisynthesis of peptoid/PEG-RNase S protein hybrids, and cyclic peptide synthesis including cyclic tetrapeptides, cyclomontanin B, yunnanin C, mahafacyclin B, and daptomycin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. α-Peptide/ß-Peptoid Chimeras

    DEFF Research Database (Denmark)

    Olsen, Christian Adam; Bonke, Gitte; Vedel, Line

    2007-01-01

    We describe the synthesis and characterization of the first generation of oligomers consisting of alternating repeats of a-amino acids and chiral N-alkyl-ß-alanine (ß-peptoid) residues. These chimeras are stable toward proteolysis, non-hemolytic, and possess antibacterial activity comparable...... to well-known antimicrobial agents. Moreover, the chimeras exhibit length-dependent, concentration-dependent, solvent-dependent, and ion-strength-dependent ellipticity, indicating the presence of a secondary structure in solution. Thus, a-peptide/ß-peptoid oligomers represent a promising novel...

  6. Peptide aldehyde inhibitors of bacterial peptide deformylases.

    Science.gov (United States)

    Durand, D J; Gordon Green, B; O'Connell, J F; Grant, S K

    1999-07-15

    Bacterial peptide deformylases (PDF, EC 3.5.1.27) are metalloenzymes that cleave the N-formyl groups from N-blocked methionine polypeptides. Peptide aldehydes containing a methional or norleucinal inhibited recombinant peptide deformylase from gram-negative Escherichia coli and gram-positive Bacillus subtilis. The most potent inhibitor was calpeptin, N-CBZ-Leu-norleucinal, which was a competitive inhibitor of the zinc-containing metalloenzymes, E. coli and B. subtilis PDF with Ki values of 26.0 and 55.6 microM, respectively. Cobalt-substituted E. coli and B. subtilis deformylases were also inhibited by these aldehydes with Ki values for calpeptin of 9.5 and 12.4 microM, respectively. Distinct spectral changes were observed upon binding of calpeptin to the Co(II)-deformylases, consistent with the noncovalent binding of the inhibitor rather than the formation of a covalent complex. In contrast, the chelator 1,10-phenanthroline caused the time-dependent inhibition of B. subtilis Co(II)-PDF activity with the loss of the active site metal. The fact that calpeptin was nearly equipotent against deformylases from both gram-negative and gram-positive bacterial sources lends further support to the idea that a single deformylase inhibitor might have broad-spectrum antibacterial activity. Copyright 1999 Academic Press.

  7. Peptide functionalized gold nanoparticles: the influence of pH on binding efficiency

    Science.gov (United States)

    Harrison, Emma; Hamilton, Jeremy W. J.; Macias-Montero, Manuel; Dixon, Dorian

    2017-07-01

    We report herein on the synthesis of mixed monolayer gold nanoparticles (AuNPs) capped with both polyethylene glycol (PEG) and one of three peptides. Either a receptor-mediated endocytosis peptide, an endosomal escape pathway (H5WYG) peptide or the Nrp-1 targeting RGD peptide (CRGDK) labeled with FITC. All three peptides have a thiol containing cysteine residue which can be used to bind the peptides to the AuNPs. In order to investigate the influence of pH on peptide attachment, PEGylated AuNPs were centrifuged, the supernatant removed, and the nanoparticles were then re-suspended in a range of pH buffer solutions above, below and at the respective isoelectric points of the peptides before co-functionalization. Peptide attachment was investigated using dynamic light scattering, Ultra-violet visible spectroscopy (UV/Vis), FTIR and photo luminescence spectroscopy. UV/Vis analysis coupled with protein assay results and photoluminescence of the FITC tagged RGD peptide concluded that a pH of ∼8 optimized the cysteine binding and stability, irrespective of the peptide used.

  8. Quality evaluation of synthetic quorum sensing peptides used in R&D

    Directory of Open Access Journals (Sweden)

    Frederick Verbeke

    2015-06-01

    Full Text Available Peptides are becoming an important class of molecules in the pharmaceutical field. Closely related peptide-impurities in peptides are inherent to the synthesis approach and have demonstrated to potentially mask biomedical experimental results. Quorum sensing peptides are attracting high interest in R&D and therefore a representative set of quorum sensing peptides, with a requested purity of at least 95.0%, was evaluated for their purity and nature of related impurities. In-house quality control (QC revealed a large discrepancy between the purity levels as stated on the supplier׳s certificate of analysis and our QC results. By using our QC analysis flowchart, we demonstrated that only 44.0% of the peptides met the required purity. The main compound of one sample was even found to have a different structure compared to the desired peptide. We also found that the majority of the related impurities were lacking amino acid(s in the desired peptide sequence. Relying on the certificates of analysis as provided by the supplier might have serious consequences for peptide research, and peptide-researchers should implement and maintain a thorough in-house QC. Keywords: Quorum sensing peptides, Quality, Impurity profiling

  9. In vitro determination of the short-chain synthetic peptide RP13 antimicrobial activity.

    Science.gov (United States)

    Sánchez, Adrián; Calderón, Ernesto; Castañón-Alonso, Sandra L; Santos, Araceli; Hernández, Beatriz; Vázquez, Alfredo

    2014-01-01

    The proliferation of antibiotic-resistant microorganisms, along with the lack of new drugs against them, has elicited the interest of the scientific community on the study and development of endogenous synthetic compounds with bacteriostatic or bactericidal activity. In recent years, several short-chain, low molecular weight peptides isolated from natural sources such as plants and animals have demonstrated an array of antimicrobial activities. Despite having structural characteristics similar to microbicidal peptides isolated from human platelets, peptide RP11 does not exhibit antimicrobial activity. In vitro determination of the antimicrobial activity of the synthetic peptide RP13. Peptide RP13 was prepared modifying the original amino acids sequence of peptide RP11, reversing the position of the amino acids lysine and tyrosine in order to modify the conformation of the original peptide. These amino acids are localized close to the N-terminus of the peptidic chain. Peptide RP13 was prepared in solution using conventional methods for peptide synthesis. The antimicrobial activity of RP13 was assessed against the microorganisms S. aureus, E. faecalis and E. coli in a test solution and later evaluated by cultivation of plates during the first 2 h after inoculation of bacteria. RP13 activity antimicrobial was compared against tetracycline, a broad-spectrum antibiotic. The new peptide RP13, resulting form the structural modification of the amino acid sequence of peptide RP11, displayed antimicrobial activity. RP13 demonstrated to be more efficient inhibiting the growth of gram-positive than gramnegative bacteria. The structural modification of peptide RP11, obtained from human platelets, resulted in a new peptide with improved antimicrobial activity. These results clearly demonstrate that peptides of natural origin, as well as their synthetic analogs, represent an attractive alternative against pathogenic agents.

  10. The discovery of new potent non-peptide Angiotensin II AT1 receptor blockers: A concise synthesis, molecular docking studies and biological evaluation of N-substituted 5-butylimidazole derivatives

    Czech Academy of Sciences Publication Activity Database

    Agelis, G.; Resvani, A.; Durdagi, S.; Spyridaki, K.; Tůmová, Tereza; Slaninová, Jiřina; Giannopoulos, P.; Vlahakos, D.; Liapakis, G.; Mavromoustakos, T.; Matsoukas, J.

    2012-01-01

    Roč. 55, Sep (2012), s. 358-374 ISSN 0223-5234 Institutional research plan: CEZ:AV0Z40550506 Keywords : synthesis * angiotensin II receptor blockers * N-substituted 5-butylimidazole derivatives * antihypertensive activity * molecular docking Subject RIV: CC - Organic Chemistry Impact factor: 3.499, year: 2012

  11. Synthesis of DOTA-conjugated multimeric [Tyr3]octreotide peptides via a combination of Cu(I)-catalyzed "click" cycloaddition and thio acid/sulfonyl azide "sulfo-click" amidation and their in vivo evaluation.

    NARCIS (Netherlands)

    Yim, C.B.; Dijkgraaf, I.; Merkx, R.; Versluis, C.; Eek, A.; Mulder, G.E.; Rijkers, D.T.; Boerman, O.C.; Liskamp, R.M.

    2010-01-01

    Herein, we describe the design, synthesis, and biological evaluation of a series of DOTA-conjugated monomeric, dimeric, and tetrameric [Tyr(3)]octreotide-based analogues as a tool for tumor imaging and/or radionuclide therapy. These compounds were synthesized using a Cu(I)-catalyzed 1,3-dipolar

  12. Granin-derived peptides.

    Science.gov (United States)

    Troger, Josef; Theurl, Markus; Kirchmair, Rudolf; Pasqua, Teresa; Tota, Bruno; Angelone, Tommaso; Cerra, Maria C; Nowosielski, Yvonne; Mätzler, Raphaela; Troger, Jasmin; Gayen, Jaur R; Trudeau, Vance; Corti, Angelo; Helle, Karen B

    2017-07-01

    The granin family comprises altogether 7 different proteins originating from the diffuse neuroendocrine system and elements of the central and peripheral nervous systems. The family is dominated by three uniquely acidic members, namely chromogranin A (CgA), chromogranin B (CgB) and secretogranin II (SgII). Since the late 1980s it has become evident that these proteins are proteolytically processed, intragranularly and/or extracellularly into a range of biologically active peptides; a number of them with regulatory properties of physiological and/or pathophysiological significance. The aim of this comprehensive overview is to provide an up-to-date insight into the distribution and properties of the well established granin-derived peptides and their putative roles in homeostatic regulations. Hence, focus is directed to peptides derived from the three main granins, e.g. to the chromogranin A derived vasostatins, betagranins, pancreastatin and catestatins, the chromogranin B-derived secretolytin and the secretogranin II-derived secretoneurin (SN). In addition, the distribution and properties of the chromogranin A-derived peptides prochromacin, chromofungin, WE14, parastatin, GE-25 and serpinins, the CgB-peptide PE-11 and the SgII-peptides EM66 and manserin will also be commented on. Finally, the opposing effects of the CgA-derived vasostatin-I and catestatin and the SgII-derived peptide SN on the integrity of the vasculature, myocardial contractility, angiogenesis in wound healing, inflammatory conditions and tumors will be discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Peptide Optical waveguides.

    Science.gov (United States)

    Handelman, Amir; Apter, Boris; Shostak, Tamar; Rosenman, Gil

    2017-02-01

    Small-scale optical devices, designed and fabricated onto one dielectric substrate, create integrated optical chip like their microelectronic analogues. These photonic circuits, based on diverse physical phenomena such as light-matter interaction, propagation of electromagnetic waves in a thin dielectric material, nonlinear and electro-optical effects, allow transmission, distribution, modulation, and processing of optical signals in optical communication systems, chemical and biological sensors, and more. The key component of these optical circuits providing both optical processing and photonic interconnections is light waveguides. Optical confinement and transmitting of the optical waves inside the waveguide material are possible due to the higher refractive index of the waveguides in comparison with their surroundings. In this work, we propose a novel field of bionanophotonics based on a new concept of optical waveguiding in synthetic elongated peptide nanostructures composed of ordered peptide dipole biomolecules. New technology of controllable deposition of peptide optical waveguiding structures by nanofountain pen technique is developed. Experimental studies of refractive index, optical transparency, and linear and nonlinear waveguiding in out-of-plane and in-plane diphenylalanine peptide nanotubes have been conducted. Optical waveguiding phenomena in peptide structures are simulated by the finite difference time domain method. The advantages of this new class of bio-optical waveguides are high refractive index contrast, wide spectral range of optical transparency, large optical nonlinearity, and electro-optical effect, making them promising for new applications in integrated multifunctional photonic circuits. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  14. Diversity-oriented peptide stapling

    DEFF Research Database (Denmark)

    Tran, Thu Phuong; Larsen, Christian Ørnbøl; Røndbjerg, Tobias

    2017-01-01

    The introduction of macrocyclic constraints in peptides (peptide stapling) is an important tool within peptide medicinal chemistry for stabilising and pre-organising peptides in a desired conformation. In recent years, the copper-catalysed azide-alkyne cycloaddition (CuAAC) has emerged as a power......The introduction of macrocyclic constraints in peptides (peptide stapling) is an important tool within peptide medicinal chemistry for stabilising and pre-organising peptides in a desired conformation. In recent years, the copper-catalysed azide-alkyne cycloaddition (CuAAC) has emerged...... incorporating two azide-modified amino acids with 1,3,5-triethynylbenzene efficiently provides (i, i+7)- and (i, i+9)-stapled peptides with a single free alkyne positioned on the staple, that can be further conjugated or dimerised. A unique feature of the present method is that it provides easy access...

  15. [Peptide inhibitors of myosin light chain kinase. Development of peptidase resistant analogues].

    Science.gov (United States)

    Sekridova, A V; Sidorova, M V; Az'muko, A A; Molokoedov, A S; Bushuev, V N; Marchenko, A V; Shcherbakova, O V; Shirinskiĭ, V P; Bespalova, Zh D

    2010-01-01

    Myosin light chain kinase (MLCK) is the key regulator of various forms of cell motility including endothelial and epithelial permeability in particular. One of the potential MLCK inhibitors to be used in humans is a membrane permeable peptide H-RKKYKYRRK-NH2 (L-PIK). In present work we used solid phase peptide synthesis and Fmoc-technology to produce five modifications of L-PIK. Based on (1)H NMR analysis revealed that these peptides demonstrated improved resistance to degradation in blood plasma. One of de novo synthesized peptides, L-[MeArg(1)]PIK inhibited MLCK activity in vitro with the same efficiency as L-PIK whereas other modified peptides showed reduced inhibitory activity. D-amino acid analog of PIK was the least active inhibitor. Thus, we have demonstrated the possibility to produce an effective MLCK peptide inhibitor with increased resistance to biodegradation that is suitable for further pharmacological development.

  16. Peptide Integrated Optics.

    Science.gov (United States)

    Handelman, Amir; Lapshina, Nadezda; Apter, Boris; Rosenman, Gil

    2018-02-01

    Bio-nanophotonics is a wide field in which advanced optical materials, biomedicine, fundamental optics, and nanotechnology are combined and result in the development of biomedical optical chips. Silk fibers or synthetic bioabsorbable polymers are the main light-guiding components. In this work, an advanced concept of integrated bio-optics is proposed, which is based on bioinspired peptide optical materials exhibiting wide optical transparency, nonlinear and electrooptical properties, and effective passive and active waveguiding. Developed new technology combining bottom-up controlled deposition of peptide planar wafers of a large area and top-down focus ion beam lithography provides direct fabrication of peptide optical integrated circuits. Finding a deep modification of peptide optical properties by reconformation of biological secondary structure from native phase to β-sheet architecture is followed by the appearance of visible fluorescence and unexpected transition from a native passive optical waveguiding to an active one. Original biocompatibility, switchable regimes of waveguiding, and multifunctional nonlinear optical properties make these new peptide planar optical materials attractive for application in emerging technology of lab-on-biochips, combining biomedical photonic and electronic circuits toward medical diagnosis, light-activated therapy, and health monitoring. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Specific Inhibition of Herpes Simplex Virus DNA Polymerase by Helical Peptides Corresponding to the Subunit Interface

    Science.gov (United States)

    Digard, Paul; Williams, Kevin P.; Hensley, Preston; Brooks, Ian S.; Dahl, Charles E.; Coen, Donald M.

    1995-02-01

    The herpes simplex virus DNA polymerase consists of two subunits-a catalytic subunit and an accessory subunit, UL42, that increases processivity. Mutations affecting the extreme C terminus of the catalytic subunit specifically disrupt subunit interactions and ablate virus replication, suggesting that new antiviral drugs could be rationally designed to interfere with polymerase heterodimerization. To aid design, we performed circular dichroism (CD) spectroscopy and analytical ultracentrifugation studies, which revealed that a 36-residue peptide corresponding to the C terminus of the catalytic subunit folds into a monomeric structure with partial α-helical character. CD studies of shorter peptides were consistent with a model where two separate regions of α-helix interact to form a hairpin-like structure. The 36-residue peptide and a shorter peptide corresponding to the C-terminal 18 residues blocked UL42-dependent long-chain DNA synthesis at concentrations that had no effect on synthesis by the catalytic subunit alone or by calf thymus DNA polymerase δ and its processivity factor. These peptides, therefore, represent a class of specific inhibitors of herpes simplex virus DNA polymerase that act by blocking accessory-subunit-dependent synthesis. These peptides or their structures may form the basis for the synthesis of clinically effective drugs.

  18. Synthetic antibiofilm peptides.

    Science.gov (United States)

    de la Fuente-Núñez, César; Cardoso, Marlon Henrique; de Souza Cândido, Elizabete; Franco, Octavio Luiz; Hancock, Robert E W

    2016-05-01

    Bacteria predominantly exist as multicellular aggregates known as biofilms that are associated with at least two thirds of all infections and exhibit increased adaptive resistance to conventional antibiotic therapies. Therefore, biofilms are major contributors to the global health problem of antibiotic resistance, and novel approaches to counter them are urgently needed. Small molecules of the innate immune system called host defense peptides (HDPs) have emerged as promising templates for the design of potent, broad-spectrum antibiofilm agents. Here, we review recent developments in the new field of synthetic antibiofilm peptides, including mechanistic insights, synergistic interactions with available antibiotics, and their potential as novel antimicrobials against persistent infections caused by biofilms. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Therapeutic HIV Peptide Vaccine

    DEFF Research Database (Denmark)

    Fomsgaard, Anders

    2015-01-01

    Therapeutic vaccines aim to control chronic HIV infection and eliminate the need for lifelong antiretroviral therapy (ART). Therapeutic HIV vaccine is being pursued as part of a functional cure for HIV/AIDS. We have outlined a basic protocol for inducing new T cell immunity during chronic HIV-1...... infection directed to subdominant conserved HIV-1 epitopes restricted to frequent HLA supertypes. The rationale for selecting HIV peptides and adjuvants are provided. Peptide subunit vaccines are regarded as safe due to the simplicity, quality, purity, and low toxicity. The caveat is reduced immunogenicity...

  20. Peptide Vaccine Against Paracoccidioidomycosis.

    Science.gov (United States)

    Taborda, Carlos P; Travassos, Luiz R

    2017-01-01

    The chapter reviews methods utilized for the isolation and characterization of a promising immunogen candidate, aiming at a human vaccine against paracoccidioidomycosis. Peptide P10 carries a T-CD4+ epitope and was identified as an internal sequence of the major diagnostic antigen known as gp43 glycoprotein. It successfully treated massive intratracheal infections by virulent Paracoccidioides brasiliensis in combination with chemotherapy.An introduction about the systemic mycosis was found essential to understand the various options that were considered to design prophylactic and therapeutic vaccine protocols using peptide P10.

  1. Design and Engineering Strategies for Synthetic Antimicrobial Peptides

    Science.gov (United States)

    Tossi, Alessandro

    Thousands of antimicrobial peptides (AMPs) of prokaryotic, fungal, plant, or animal origin have been identified, and their potential as lead compounds for the design of novel therapeutic agents in the treatment of infection, for stimulating the immune system, or in countering septic shock has been widely recognized. Added to this is their possible use in prophylaxis of infectious diseases for animal or plant protection, for disinfection of surgical instruments or industrial surfaces, and for food preservation among other commercially important applications. Since the early eighties, AMPs have been subject to a vast number of studies aimed at understanding what determines their potency and spectrum of activities against bacterial or fungal pathogens, and at maximizing these while limiting cytotoxic activities toward host cells. Much research has also been directed toward understanding specific mechanisms of action underlying the antimicrobial activity and selectivity, to be able to redesign the peptides for optimal performance. A central theme in the mode of action of many AMPs is their dynamic interaction with biological membranes, which involves various properties of these peptides such as, among others, surface hydrophobicity and polarity, charge, structure, and induced conformational variations. These features are often intimately interconnected so that engineering peptides to independently adjust any one property in particular is not an easy task. However, solid-phase peptide synthesis allows the use of a large repertoire of nonproteinogenic amino acids that can be used in the rational design of peptides to finely tune structural and physicochemical properties and precisely probe structure-function relationships.

  2. ER stress affects processing of MHC class I-associated peptides

    Directory of Open Access Journals (Sweden)

    Meloche Sylvain

    2009-02-01

    Full Text Available Abstract Background Viral infection and neoplastic transformation trigger endoplasmic reticulum (ER stress. Thus, a large proportion of the cells that must be recognized by the immune system are stressed cells. Cells respond to ER stress by launching the unfolded protein response (UPR. The UPR regulates the two key processes that control major histocompatibility complex class I (MHC I-peptide presentation: protein synthesis and degradation. We therefore asked whether and how the UPR impinges on MHC I-peptide presentation. Results We evaluated the impact of the UPR on global MHC I expression and on presentation of the H2Kb-associated SIINFEKL peptide. EL4 cells stably transfected with vectors coding hen egg lysozyme (HEL-SIINFEKL protein variants were stressed with palmitate or exposed to glucose deprivation. UPR decreased surface expression of MHC I but did not affect MHC I mRNA level nor the total amount of intracellular MHC I proteins. Impaired MHC I-peptide presentation was due mainly to reduced supply of peptides owing to an inhibition of overall protein synthesis. Consequently, generation of H2Kb-SIINFEKL complexes was curtailed during ER stress, illustrating how generation of MHC I peptide ligands is tightly coupled to ongoing protein synthesis. Notably, the UPR-induced decline of MHC I-peptide presentation was more severe when the protein source of peptides was localized in the cytosol than in the ER. This difference was not due to changes in the translation rates of the precursor proteins but to increased stability of the cytosolic protein during ER stress. Conclusion Our results demonstrate that ER stress impairs MHC I-peptide presentation, and that it differentially regulates expression of ER- vs. cytosol-derived peptides. Furthermore, this work illustrates how ER stress, a typical feature of infected and malignant cells, can impinge on cues for adaptive immune recognition.

  3. The Suzuki–Miyaura Cross-Coupling as a Versatile Tool for Peptide Diversification and Cyclization

    Directory of Open Access Journals (Sweden)

    Tom Willemse

    2017-02-01

    Full Text Available The (site-selective derivatization of amino acids and peptides represents an attractive field with potential applications in the establishment of structure–activity relationships and labeling of bioactive compounds. In this respect, bioorthogonal cross-coupling reactions provide valuable means for ready access to peptide analogues with diversified structure and function. Due to the complex and chiral nature of peptides, mild reaction conditions are preferred; hence, a suitable cross-coupling reaction is required for the chemical modification of these challenging substrates. The Suzuki reaction, involving organoboron species, is appropriate given the stability and environmentally benign nature of these reactants and their amenability to be applied in (partial aqueous reaction conditions, an expected requirement upon the derivatization of peptides. Concerning the halogenated reaction partner, residues bearing halogen moieties can either be introduced directly as halogenated amino acids during solid-phase peptide synthesis (SPPS or genetically encoded into larger proteins. A reversed approach building in boron in the peptidic backbone is also possible. Furthermore, based on this complementarity, cyclic peptides can be prepared by halogenation, and borylation of two amino acid side chains present within the same peptidic substrate. Here, the Suzuki–Miyaura reaction is a tool to induce the desired cyclization. In this review, we discuss diverse amino acid and peptide-based applications explored by means of this extremely versatile cross-coupling reaction. With the advent of peptide-based drugs, versatile bioorthogonal conversions on these substrates have become highly valuable.

  4. High throughput screening methods for assessing antibiofilm and immunomodulatory activities of synthetic peptides.

    Science.gov (United States)

    Haney, Evan F; Mansour, Sarah C; Hilchie, Ashley L; de la Fuente-Núñez, César; Hancock, Robert E W

    2015-09-01

    The recent observation that certain cationic peptides possess potent antibiofilm activity demonstrated that small peptides could be used to treat biofilm-associated infections. Other so-called innate defense regulator peptides possess potent immunomodulatory properties such as leukocyte recruitment and suppression of harmful inflammation. A peptide that directly targets biofilm cells while favorably modulating the immune response would be particularly advantageous for treating serious skin infections caused by Staphylococcus aureus. In the present work, using SPOT-synthesized peptide arrays on cellulose membranes, we outline a strategy for systematically assessing the antibiofilm activity of hundreds of IDR-1002 (VQRWLIVWRIRK-NH2) and IDR-HH2 (VQLRIRVAVIRA-NH2) peptide variants against MRSA biofilms. In addition, the ability of these peptides to stimulate production of a monocyte chemoattractant protein (MCP-1) and suppress LPS-induced interleukin (IL)-1β production in human peripheral blood mononuclear cells (PBMCs) was evaluated. These results informed the synthesis of second-generation peptides resulting in a new peptide, IDR-2009 (KWRLLIRWRIQK-NH2), with enhanced MCP-1 stimulatory activity, favorable IL-1β suppression characteristics and strong antibiofilm activity against MRSA and Pseudomonas aeruginosa biofilms. This work provides a proof-of-concept that multiple peptide activities can be optimized simultaneously to generate novel sequences that possess a variety of biological properties. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Beta-Sheet-Forming, Self-Assembled Peptide Nanomaterials towards Optical, Energy, and Healthcare Applications.

    Science.gov (United States)

    Kim, Sungjin; Kim, Jae Hong; Lee, Joon Seok; Park, Chan Beum

    2015-08-12

    Peptide self-assembly is an attractive route for the synthesis of intricate organic nanostructures that possess remarkable structural variety and biocompatibility. Recent studies on peptide-based, self-assembled materials have expanded beyond the construction of high-order architectures; they are now reporting new functional materials that have application in the emerging fields such as artificial photosynthesis and rechargeable batteries. Nevertheless, there have been few reviews particularly concentrating on such versatile, emerging applications. Herein, recent advances in the synthesis of self-assembled peptide nanomaterials (e.g., cross β-sheet-based amyloid nanostructures, peptide amphiphiles) are selectively reviewed and their new applications in diverse, interdisciplinary fields are described, ranging from optics and energy storage/conversion to healthcare. The applications of peptide-based self-assembled materials in unconventional fields are also highlighted, such as photoluminescent peptide nanostructures, artificial photosynthetic peptide nanomaterials, and lithium-ion battery components. The relation of such functional materials to the rapidly progressing biomedical applications of peptide self-assembly, which include biosensors/chips and regenerative medicine, are discussed. The combination of strategies shown in these applications would further promote the discovery of novel, functional, small materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. NCAM Mimetic Peptides: An Update

    DEFF Research Database (Denmark)

    Berezin, Vladimir; Bock, Elisabeth

    2008-01-01

    of combinatorial peptide libraries. The C3 and NBP10 peptides target the first Ig module whereas the ENFIN2 and ENFIN11 peptides target fibronectin type III (FN3) modules of NCAM. A number of NCAM mimetics can induce neurite outgrowth and exhibit neuroprotective and synaptic plasticity modulating properties...

  7. brain natriuretic peptide

    African Journals Online (AJOL)

    Background: Recently brain natriuretic peptide (BNP) level has been introduced as a screening test for congestive heart failure (CHF) in children. The current CHF assessment scores are not satisfactory as they use a large number of variables. Objective: To evaluate two CHF scores: a modified clinical score and an echo-.

  8. Brain Peptides and Psychopharmacology

    Science.gov (United States)

    Arehart-Treichel, Joan

    1976-01-01

    Proteins isolated from the brain and used as drugs can improve and apparently even transfer mental states and behavior. Much of the pioneering work and recent research with humans and animals is reviewed and crucial questions that are being posed about the psychologically active peptides are related. (BT)

  9. Design and synthesis of a novel class of sugar-peptide hybrids: C-linked glyco beta-amino acids through a stereoselective "acetate" Mannich reaction as the key strategic element.

    Science.gov (United States)

    Palomo, Claudio; Oiarbide, Mikel; Landa, Aitor; González-Rego, M Concepción; García, Jesús M; González, Alberto; Odriozola, José M; Martín-Pastor, Manuel; Linden, Anthony

    2002-07-24

    A new type of sugar-amino acid hybrid, which is comprised of a sugar unit (gluco-, galacto-, or mannopyranose) linked through a C-glycosidic linkage to the beta-position of an alpha-unsubstituted beta-amino acid unit, is presented. It is hypothesized that these new compounds, or the oligomeric peptides derived therefrom, might possess the structural features of beta-amino acid oligomers and the chemical and enzymatic resistance of C-glycosides to hydrolysis. The synthetic strategy is based on a new Mannich-type reaction between a chiral acetate enolate equivalent and alpha-amido sulfones derived from the corresponding sugar-C-glycoside aldehydes. While the sugar-C-glycoside aldehyde partner is prepared from well-established transformations on known sugar precursors, the lithium enolate derived from (1R)-endo-2-acetylisoborneol 3 is employed as the key element. This Mannich approach proceeds with essentially perfect diasteromeric control leading to the new beta-amino carbonyl adducts in good yields. Further, cleavage of the camphor auxiliary is smoothly performed by oxidative treatment with ammonium cerium nitrate (CAN). Complementarily, direct peptide-type coupling of the beta-amino carbonyl Mannich adducts with an alpha- or beta-amino acid residue and subsequent CAN-promoted detachment of the auxiliary yields dipeptide fragments bearing a sugar-containing aliphatic side chain and is a process that can be iterated. A preliminary conformational study based on the combination of experimental NMR data and molecular mechanics and molecular dynamics (MD) of one particular adduct is also provided.

  10. [Biosynthesis of opioid peptides].

    Science.gov (United States)

    Rossier, J

    1988-01-01

    The endogenous opioid peptides all contain the enkephalin sequence Tyr-Gly-Gly-Phe-Met and Tyr-Gly-Gly-Phe-Leu at their aminoterminus. Three distinct families of these peptides (endorphins, enkephalins and dynorphins) are present in different neuronal pathways within the central nervous system. Molecular genetics have shown that these three families of opioid peptides are derived from three distinct precursors. Pro-opiomelanocortin gives rise to the endorphins, as well as adrenocorticotropic hormone (ACTH) and the melanotropic hormones (MSH's). [Met] enkephalin, [Leu] enkephalin and the related heptapeptide [Met] enkephalin-Arg6-Phe7 and octapeptide [Met] enkephalin-Arg6-Gly7-Leu8 are derived from proenkephalin. The third family is derived from prodynorphin and includes dynorphin A, dynorphin B (also known as rimorphin) and alpha- and beta-neo-endorphin. The structure of the genes coding for these precursors are similar, suggesting the possibility of one common ancestral gene. The most common scheme for enzymatic maturation of precursors proposes the action of a trypsin-like endopeptidase followed by a carboxypeptidase B-like exopeptidase. However, we have provided evidence that this combination of trypsin-like and carboxypeptidase B-like enzymes may not be the only mechanism for liberating enkephalin from low molecular weight enkephalin-containing peptides. Indeed, endo-oligopeptidase A, an enzyme, known to hydrolyze the Phe5-Ser6 bond of bradykinin and the Arg8-Arg9 bond of neurotensin, has been shown to produce, by a single cleavage, [Leu] enkephalin or [Met] enkephalin from small enkephalin-containing peptides, (Camargo et al., 1987, J. Neurochem. 48, 1258-1263).(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Cancer therapy with alpha-emitters labeled peptides.

    Science.gov (United States)

    Dadachova, Ekaterina

    2010-05-01

    Actively targeted alpha-particles offer specific tumor cell killing action with less collateral damage to surrounding normal tissues than beta-emitters. During the last decade, radiolabeled peptides that bind to different receptors on the tumors have been investigated as potential therapeutic agents both in the preclinical and clinical settings. Advantages of radiolabeled peptides over antibodies include relatively straightforward chemical synthesis, versatility, easier radiolabeling, rapid clearance from the circulation, faster penetration and more uniform distribution into tissues, and less immunogenicity. Rapid internalization of the radiolabeled peptides with equally rapid re-expression of the cell surface target is a highly desirable property that enhances the total delivery of these radionuclides into malignant sites. Peptides, such as octreotide, alpha-melanocyte-stimulating hormone analogues, arginine-glycine-aspartic acid-containing peptides, bombesin derivatives, and others may all be feasible for use with alpha-emitters. The on-going preclinical work has primarily concentrated on octreotide and octreotate analogues labeled with Bismuth-213 and Astatine-211. In addition, alpha-melanocyte-stimulating hormone analogue has been labeled with Lead-212/Bismuth-212 in vivo generator and demonstrated the encouraging therapeutic efficacy in treatment of experimental melanoma. Obstacles that continue to obstruct widespread acceptance of alpha-emitter-labeled peptides are primarily the supply of these radionuclides and concerns about potential kidney toxicity. New sources and methods for production of these medically valuable radionuclides and better understanding of mechanisms related to the peptide renal uptake and clearance should speed up the introduction of alpha-emitter-labeled peptides into the clinic. Copyright 2010 Elsevier Inc. All rights reserved.

  12. Prediction of cell penetrating peptides by support vector machines.

    Directory of Open Access Journals (Sweden)

    William S Sanders

    2011-07-01

    Full Text Available Cell penetrating peptides (CPPs are those peptides that can transverse cell membranes to enter cells. Once inside the cell, different CPPs can localize to different cellular components and perform different roles. Some generate pore-forming complexes resulting in the destruction of cells while others localize to various organelles. Use of machine learning methods to predict potential new CPPs will enable more rapid screening for applications such as drug delivery. We have investigated the influence of the composition of training datasets on the ability to classify peptides as cell penetrating using support vector machines (SVMs. We identified 111 known CPPs and 34 known non-penetrating peptides from the literature and commercial vendors and used several approaches to build training data sets for the classifiers. Features were calculated from the datasets using a set of basic biochemical properties combined with features from the literature determined to be relevant in the prediction of CPPs. Our results using different training datasets confirm the importance of a balanced training set with approximately equal number of positive and negative examples. The SVM based classifiers have greater classification accuracy than previously reported methods for the prediction of CPPs, and because they use primary biochemical properties of the peptides as features, these classifiers provide insight into the properties needed for cell-penetration. To confirm our SVM classifications, a subset of peptides classified as either penetrating or non-penetrating was selected for synthesis and experimental validation. Of the synthesized peptides predicted to be CPPs, 100% of these peptides were shown to be penetrating.

  13. Biochemical functionalization of peptide nanotubes with phage displayed peptides

    Science.gov (United States)

    Swaminathan, Swathi; Cui, Yue

    2016-09-01

    The development of a general approach for the biochemical functionalization of peptide nanotubes (PNTs) could open up existing opportunities in both fundamental studies as well as a variety of applications. PNTs are spontaneously assembled organic nanostructures made from peptides. Phage display has emerged as a powerful approach for identifying selective peptide binding motifs. Here, we demonstrate for the first time the biochemical functionalization of PNTs via peptides identified from a phage display peptide library. The phage-displayed peptides are shown to recognize PNTs. These advances further allow for the development of bifunctional peptides for the capture of bacteria and the self-assembly of silver particles onto PNTs. We anticipate that these results could provide significant opportunities for using PNTs in both fundamental studies and practical applications, including sensors and biosensors nanoelectronics, energy storage devices, drug delivery, and tissue engineering.

  14. Synthetic antimicrobial peptides of the halictines family disturb the membrane integrity of Candida cells.

    Science.gov (United States)

    Kodedová, Marie; Sychrová, Hana

    2017-10-01

    We compared the potency of four derivatives of the antimicrobial peptide halictine-2 against six Candida species. Observed activity was peptide and species specific. Halictines rapidly permeabilized cell membranes and caused the leakage of cytosolic components. Their killing potential was enhanced by the commercial antimicrobial agent octenidine dihydrochloride. The effect on C. glabrata cells did not depend on the activity of Cdr pumps, but was influenced by their lipid composition. The pre-treatment of cells with myriocin, an inhibitor of sphingolipid synthesis, enhanced the peptides' activity, whereas pre-treatment with terbinafine and fluconazole, inhibitors of sterol synthesis, significantly weakened their efficacy. The killing efficacy of peptides increased in combination with amphotericin B. Thus the mode of action of halictines is likely to depend on the plasma-membrane sterols, which might explain the observed differences among the tested Candida species. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Changes in Bone Alkaline Phosphatase and Procollagen Type-1 C-Peptide after Static and Dynamic Exercises

    Science.gov (United States)

    Kubo, Keitaro; Yuki, Kazuhito; Ikebukuro, Toshihiro

    2012-01-01

    We investigated the effects of two types of nonweight-bearing exercise on changes in bone-specific alkaline phosphatase (BAP) and pro-collagen type 1 C-peptide (P1P). BAP is a specific marker of bone synthesis, whereas P1P reflects synthesis of type 1 collagen in other organs as well as bone. Eight participants performed static and dynamic…

  16. [Amides of amino acids and peptides as antifungal agents].

    Science.gov (United States)

    Giori, P; Vertuani, G; Mazzotta, D; Guarneri, M; Pancaldi, D; Brunelli, A

    1982-07-01

    The synthesis of pyrazolyl-amides of aminoacids and peptides is described. The chemicals were tested for antifungal activity against wheat powdery mildew (Erysiphe graminis DC.), cucumber powdery mildew (Erysiphe cichoracearum DC.), wheat brown rust (Puccinia recondita Rob. ex Desm. f. sp. tritici Erikss et Henn.), celery leaf spot (Septoria Apii Briosi ed Cav. Chest.) and collar rot (Rhizoctonia solani Kuhn). Some of these compounds showed antifungal activity.

  17. Lasiocepsin, a novel cyclic antimicrobial peptide from the venom of eusocial bee Lasioglossum laticeps (Hymenoptera: Halictidae)

    Czech Academy of Sciences Publication Activity Database

    Monincová, Lenka; Slaninová, Jiřina; Fučík, Vladimír; Hovorka, Oldřich; Voburka, Zdeněk; Bednárová, Lucie; Maloň, Petr; Štokrová, Jitka; Čeřovský, Václav

    2012-01-01

    Roč. 43, č. 2 (2012), s. 751-761 ISSN 0939-4451 R&D Projects: GA ČR GA203/08/0536; GA ČR GAP205/10/1276 Grant - others:GAUK(CZ) 33779266 Keywords : antimicrobial peptides * disulfide bridge * analogs * peptide synthesis * wild- bee venom * CD spectroscopy Subject RIV: CE - Biochemistry Impact factor: 3.914, year: 2012

  18. Overcoming the membrane barrier: Recruitment of γ-glutamyl transferase for intracellular release of metabolic cargo from peptide vectors.

    Science.gov (United States)

    Kuenzl, Tilmann; Sroka, Magdalena; Srivastava, Puneet; Herdewijn, Piet; Marlière, Philippe; Panke, Sven

    2017-01-01

    Semipermeable membranes of cells frequently pose an obstacle in metabolic engineering by limiting uptake of substrates, intermediates, or xenobiotics. Previous attempts to overcome this barrier relied on the promiscuous nature of peptide transport systems, but often suffered from low versatility or chemical instability. Here, we present an alternative strategy to transport cargo molecules across the inner membrane of Escherichia coli based on chemical synthesis of a stable cargo-peptide vector construct, transport through the peptide import system, and efficient intracellular release of the cargo by the promiscuous enzyme γ-glutamyl transferase (GGT). Retaining the otherwise periplasmic GGT in the cytoplasm was critical for the functionality of the system, as was fine-tuning its expression in order to minimize toxic effects associated to cytoplasmic GGT expression. Given the established protocols of peptide synthesis and the flexibility of peptide transport and GGT, the system is expected to be suitable for a broad range of cargoes. Copyright © 2016. Published by Elsevier Inc.

  19. Antimicrobial Peptides (AMPs

    Directory of Open Access Journals (Sweden)

    Mehrzad Sadredinamin

    2016-04-01

    Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

  20. Asymmetric Synthesis of Apratoxin E.

    Science.gov (United States)

    Mao, Zhuo-Ya; Si, Chang-Mei; Liu, Yi-Wen; Dong, Han-Qing; Wei, Bang-Guo; Lin, Guo-Qiang

    2016-10-21

    An efficient method for asymmetric synthesis of apratoxin E 2 is described in this report. The chiral lactone 8, recycled from the degradation of saponin glycosides, was utilized to prepare the non-peptide fragment 6. In addition to this "from nature to nature" strategy, olefin cross-metathesis (CM) was applied as an alternative approach for the formation of the double bond. Moreover, pentafluorophenyl diphenylphosphinate was found to be an efficient condensation reagent for the macrocyclization.

  1. Molecular evolution of a peptide GPCR ligand driven by artificial neural networks.

    Directory of Open Access Journals (Sweden)

    Sebastian Bandholtz

    Full Text Available Peptide ligands of G protein-coupled receptors constitute valuable natural lead structures for the development of highly selective drugs and high-affinity tools to probe ligand-receptor interaction. Currently, pharmacological and metabolic modification of natural peptides involves either an iterative trial-and-error process based on structure-activity relationships or screening of peptide libraries that contain many structural variants of the native molecule. Here, we present a novel neural network architecture for the improvement of metabolic stability without loss of bioactivity. In this approach the peptide sequence determines the topology of the neural network and each cell corresponds one-to-one to a single amino acid of the peptide chain. Using a training set, the learning algorithm calculated weights for each cell. The resulting network calculated the fitness function in a genetic algorithm to explore the virtual space of all possible peptides. The network training was based on gradient descent techniques which rely on the efficient calculation of the gradient by back-propagation. After three consecutive cycles of sequence design by the neural network, peptide synthesis and bioassay this new approach yielded a ligand with 70fold higher metabolic stability compared to the wild type peptide without loss of the subnanomolar activity in the biological assay. Combining specialized neural networks with an exploration of the combinatorial amino acid sequence space by genetic algorithms represents a novel rational strategy for peptide design and optimization.

  2. Stabilization of peptides against proteolysis through disulfide-bridged conjugation with synthetic aromatics.

    Science.gov (United States)

    Chen, Yaqi; Li, Tao; Li, Jianguo; Cheng, Shiyan; Wang, Jinghui; Verma, Chandra; Zhao, Yibing; Wu, Chuanliu

    2017-02-22

    Peptides have been promising molecular scaffolds for the development of potential therapeutics with high affinity and specificity to biomacromolecules. However, their inherent proteolytic instability significantly hampers their biological applications. Strategies that can stabilize peptides against proteolytic digestion on the basis of noncovalent interactions-without extensive manipulation of the sequence or use of unnatural residues-are greatly desired. In this work, we developed a general, convenient, and efficient strategy for the stabilization of peptides against proteolysis, which involves noncovalent π-π interactions between aromatic amino acid residues in peptides and synthetic electron-deficient aromatics (NDI), together with the implication of steric hindrance (from the bulky NDI moiety), and the enhancement of peptide α-helicity. This strategy is complementary in concept to the conventional well-established covalent approaches for peptide stabilization, and is thus promising for being utilized, in combination with the latter ones, to circumvent the problem of proteolytic instability of peptides. We envisioned that this study should provide invaluable guidelines to the design and synthesis of organic molecule-peptide hybrids with significantly improved proteolytic resistance, and benefit the development of peptide therapeutics and probes.

  3. Toward greener analytical techniques for the absolute quantification of peptides in pharmaceutical and biological samples.

    Science.gov (United States)

    Van Eeckhaut, Ann; Mangelings, Debby

    2015-09-10

    Peptide-based biopharmaceuticals represent one of the fastest growing classes of new drug molecules. New reaction types included in the synthesis strategies to reduce the rapid metabolism of peptides, along with the availability of new formulation and delivery technologies, resulted in an increased marketing of peptide drug products. In this regard, the development of analytical methods for quantification of peptides in pharmaceutical and biological samples is of utmost importance. From the sample preparation step to their analysis by means of chromatographic or electrophoretic methods, many difficulties should be tackled to analyze them. Recent developments in analytical techniques emphasize more and more on the use of green analytical techniques. This review will discuss the progresses in and challenges observed during green analytical method development for the quantification of peptides in pharmaceutical and biological samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Synthetic Peptide-Based ELISA and ELISpot Assay for Identifying Autoantibody Epitopes.

    Science.gov (United States)

    Pozsgay, Judit; Szarka, Eszter; Huber, Krisztina; Babos, Fruzsina; Magyar, Anna; Hudecz, Ferenc; Sarmay, Gabriella

    2016-01-01

    Enzyme-linked immunosorbent assay (ELISA) is an invaluable diagnostic tool to detect serum autoantibody binding to target antigen. To map the autoantigenic epitope(s), overlapping synthetic peptides covering the total sequence of a protein antigen are used. A large set of peptides synthesized on the crown of pins can be tested by Multipin ELISA for fast screening. Next, to validate the results, the candidate epitope peptides are resynthesized by solid-phase synthesis, coupled to ELISA plate directly, or in a biotinylated form, bound to neutravidin-coated surface and the binding of autoantibodies from patients' sera is tested by indirect ELISA. Further, selected epitope peptides can be applied in enzyme-linked immunospot assay to distinguish individual, citrullinated peptide-specific autoreactive B cells in a pre-stimulated culture of patients' lymphocytes.

  5. An evolutionary perspective on signaling peptides: toxic peptides are selected to provide information regarding the processing of the propeptide, which represents the phenotypic state of the signaling cell [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Keith Daniel Harris

    2015-08-01

    Full Text Available Structurally similar short peptides often serve as signals in diverse signaling systems. Similar peptides affect diverse physiological pathways in different species or even within the same organism. Assuming that signals provide information, and that this information is tested by the structure of the signal, it is curious that highly similar signaling peptides appear to provide information relevant to very different metabolic processes. Here we suggest a solution to this problem: the synthesis of the propeptide, and its post-translational modifications that are required for its cleavage and the production of the mature peptide, provide information on the phenotypic state of the signaling cell. The mature peptide, due to its chemical properties which render it harmful, serves as a stimulant that forces cells to respond to this information. To support this suggestion, we present cases of signaling peptides in which the sequence and structure of the mature peptide is similar yet provides diverse information. The sequence of the propeptide and its post-translational modifications, which represent the phenotypic state of the signaling cell, determine the quantity and specificity of the information. We also speculate on the evolution of signaling peptides. We hope that this perspective will encourage researchers to reevaluate pathological conditions in which the synthesis of the mature peptide is abnormal.

  6. Radiolabelled peptides vs. nanoparticle-peptide complexes for medical applications

    International Nuclear Information System (INIS)

    Ferro F, G.

    2007-01-01

    Full text: The principle that peptide receptors can be used successfully for in vivo targeting of human cancers has been provided and the peptide-receptor radionuclide therapy for malignant tumors is a real treatment option. Targeted entry into cells is an increasingly important area of research. The diagnoses and treatment of disease by novel methods would be enhanced greatly by the efficient transport of materials to living cell nuclei. Membrane-trans locating peptides complexed to nanoparticles are small enough (30 nm) to cross the nuclear membrane and to enter the cell via receptor-mediated endocytosis, emerging as a new type of pharmaceuticals. Pharmacokinetic properties and molecular specificity of iron or gold nanoparticle-peptide complexes that do not induce biological toxicity is a topic of world interest in current and future medical investigations. Some perspectives and achievements on the preparation, pharmacokinetics and dosimetry of radiolabelled peptides versus nanoparticle-peptide complexes for medical applications are presented. (Author)

  7. An efficient solid-phase synthesis of peptidyl-N-acetylguanidines for use in native chemical ligation.

    Science.gov (United States)

    Okamoto, Ryo; Isoe, Madoka; Izumi, Masayuki; Kajihara, Yasuhiro

    2016-05-01

    In the modern protocols of chemical protein syntheses, peptide-α-thioesters have been used as key components for the assembly of full-length polypeptides through chemoselective peptide coupling reactions. A variety of thioester precursors have been developed for the synthesis of the peptide-α-thioesters by Fmoc solid phase peptide synthesis (Fmoc-SPPS). Recently our group found a peptidyl-N-acetylguanidine as a new peptide-α-thioester precursor. This peptide derivative can be converted into a corresponding peptide-α-thioester only by treatment with an excess amount of a thiol in aqueous buffers at around neutral pH. This unique property allowed us to envision the practical use of the peptidyl-N-acetylguanidines for the chemical syntheses of proteins; however, an efficient synthetic method has been lacking. Herein, we report an efficient solid-phase synthesis of peptidyl-N-acetylguanidines. This new synthetic method employing selective activation and cleavage of a peptide bond successfully provided peptidyl-N-acetylguanidines from the on-resin protected peptides prepared by standard Fmoc-SPPS. We also evaluated the reactivity of a peptidyl-N-acetylguanidine in native chemical ligation through the synthesis of glucose-dependent insulinotropic polypeptide analogue. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  8. N-methylation in amino acids and peptides: Scope and limitations.

    Science.gov (United States)

    Sharma, Anamika; Kumar, Ashish; Abdel Monaim, Shimaa A H; Jad, Yahya E; El-Faham, Ayman; de la Torre, Beatriz G; Albericio, Fernando

    2018-03-12

    Active pharmaceutical ingredients (APIs) can be divided into two types, namely chemical and biological entities. Traditionally, the former has been associated with the so-called small molecules. The revival of peptides in pharmaceutical industry results from their importance in many biological roles. However, low metabolic stability and the lack of oral availability of most peptides is the main drawback for peptide to fulfill that paradigmatic situation. In this regard, efforts are being channeled into addressing this issue by introducing restrictions into the flexible peptide backbone, mainly through N-methyl amino acids (NMAAs) or development of small cyclic peptides. In many cases, both the above restrictions are combined with the aim to enhance oral availability. The synthesis of NMAAs is complex and their introduction into the peptide chain brings additional synthetic challenges and also sometimes leads to side-reactions. Here we discuss the most efficient methods for the synthesis of NMAAs (either in solution or in solid phase) and also their introduction into peptide sequences. Special attention is also given to the detection of side reactions and the most efficient way to prevent them. © 2018 Wiley Periodicals, Inc.

  9. Screening of soy protein-derived hypotriglyceridemic di-peptides in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Matsui Toshiro

    2011-05-01

    Full Text Available Abstract Background Soy protein and soy peptides have attracted considerable attention because of their potentially beneficial biological properties, including antihypertensive, anticarcinogenic, and hypolipidemic effects. Although soy protein isolate contains several bioactive peptides that have distinct physiological activities in lipid metabolism, it is not clear which peptide sequences are responsible for the triglyceride (TG-lowering effects. In the present study, we investigated the effects of soy protein-derived peptides on lipid metabolism, especially TG metabolism, in HepG2 cells and obese Otsuka Long-Evans Tokushima fatty (OLETF rats. Results In the first experiment, we found that soy crude peptide (SCP-LD3, which was prepared by hydrolyze of soy protein isolate with endo-type protease, showed hypolipidemic effects in HepG2 cells and OLETF rats. In the second experiment, we found that hydrophilic fraction, separated from SCP-LD3 with hydrophobic synthetic absorbent, revealed lipid-lowering effects in HepG2 cells and OLETF rats. In the third experiment, we found that Fraction-C (Frc-C peptides, fractionated from hydrophilic peptides by gel permeation chromatography-high performance liquid chromatography, significantly reduced TG synthesis and apolipoprotein B (apoB secretion in HepG2 cells. In the fourth experiment, we found that the fraction with 0.1% trifluoroacetic acid, isolated from Frc-C peptides by octadecylsilyl column chromatography, showed hypolipidemic effects in HepG2 cells. In the final experiment, we found that 3 di-peptides, Lys-Ala, Val-Lys, and Ser-Tyr, reduced TG synthesis, and Ser-Tyr additionally reduced apoB secretion in HepG2 cells. Conclusion Novel active peptides with TG-lowering effects from soy protein have been isolated.

  10. Peptide-enhanced oral delivery of therapeutic peptides and proteins

    DEFF Research Database (Denmark)

    Kristensen, Mie; Foged, Camilla; Berthelsen, Jens

    2013-01-01

    Systemic therapy upon oral delivery of biologics, such as peptide and protein drugs is limited due to their large molecular size, their low enzymatic stability and their inability to cross the intestinal epithelium. Ways to overcome the epithelial barrier include the use of peptide-based excipients...... throughout the gastrointestinal (GI) tract, chemical stability is an inherent challenge when employing amino acid-based excipients for oral delivery, and multiple approaches have been investigated to improve this. The exact mechanisms of transepithelial translocation are discussed, and it is believed...... for oral delivery of peptide and protein drugs highlighting recent studies and the most promising compounds from these classes of peptide excipients....

  11. Structural organization and spectroscopy of peptide-actinide(IV) complexes

    International Nuclear Information System (INIS)

    Dahou, S.

    2010-01-01

    The contamination of living organisms by actinide elements is at the origin of both radiological and chemical toxicity that may lead to severe dysfunction. Most of the data available on the actinide interaction with biological systems are macroscopic physiological measurements and are lacking a molecular description of the systems. Because of the intricacy of these systems, classical biochemical methods are difficult to implement. Our strategy consisted in designing simplified biomimetic peptides, and describing the corresponding intramolecular interactions with actinides. A carboxylic pentapeptide of the form DDPDD has been at the starting point of this work in order to further assess the influence of the peptide sequence on the topology of the complexes.To do so, various linear (Asp/Ala permutations, peptoids) and cyclic analogues have been synthesized. Furthermore, in order to include the hydroxamic function (with a high affinity for Fe(III)) in the peptide, both desferrioxamine and acetohydroxamic acid have been investigated. However because of difficulties in synthesis, we have not been able to test these peptides. Three actinide cations have been considered at oxidation state +IV (Th, Np, Pu) and compared to Fe(III), often considered as a biological surrogate of Pu(IV). The spatial arrangement of the peptide around the cation has been probed by spectrophotometry and X-ray Absorption Spectroscopy. The spectroscopic data and EXAFS data adjustment lead us to rationalize the topology of the complexes as a function of the peptide sequence: mix hydroxy polynuclear species for linear and cyclic peptides, mononuclear for the desferrioxamine complexes. Furthermore, significant differences have appeared between Fe(III) and actinide(IV), related to differences of reactivity in aqueous medium. (author)

  12. Antimicrobial Peptides: A Promising Therapeutic Strategy in Tackling Antimicrobial Resistance.

    Science.gov (United States)

    Nuti, Ramya; Goud, Nerella S; Saraswati, A Prasanth; Alvala, Ravi; Alvala, Mallika

    2017-01-01

    Antimicrobial resistance (AMR) has posed a serious threat to global public health and it requires immediate action, preferably long term. Current drug therapies have failed to curb this menace due to the ability of microbes to circumvent the mechanisms through which the drugs act. From the drug discovery point of view, the majority of drugs currently employed for antimicrobial therapy are small molecules. Recent trends reveal a surge in the use of peptides as drug candidates as they offer remarkable advantages over small molecules. Newer synthetic strategies like organometalic complexes, Peptide-polymer conjugates, solid phase, liquid phase and recombinant DNA technology encouraging the use of peptides as therapeutic agents with a host of chemical functions, and tailored for specific applications. In the last decade, many peptide based drugs have been successfully approved by the Food and Drug Administration (FDA). This success can be attributed to their high specificity, selectivity and efficacy, high penetrability into the tissues, less immunogenicity and less tissue accumulation. Considering the enormity of AMR, the use of Antimicrobial Peptides (AMPs) can be a viable alternative to current therapeutics strategies. AMPs are naturally abundant allowing synthetic chemists to develop semi-synthetics peptide molecules. AMPs have a broad spectrum of activity towards microbes and they possess the ability to bypass the resistance induction mechanisms of microbes. The present review focuses on the potential applications of AMPs against various microbial disorders and their future prospects. Several resistance mechanisms and their strategies have also been discussed to highlight the importance in the current scenario. Breakthroughs in AMP designing, peptide synthesis and biotechnology have shown promise in tackling this challenge and has revived the interest of using AMPs as an important weapon in fighting AMR. Copyright© Bentham Science Publishers; For any queries

  13. Synthesis and NMR Elucidation of Novel Pentacycloundecane ...

    African Journals Online (AJOL)

    Herein we report the synthesis and NMR elucidation of five novel pentacycloundecane (PCU)-derived short peptides as potential HIV protease inhibitors. 1H and 13C spectral analysis show major overlapping of methine resonance of the PCU 'cage' thereby making it extremely difficult to assign the NMR signals. Attachment ...

  14. Amino-terminal domain of the v-fms oncogene product includes a functional signal peptide that directs synthesis of a transforming glycoprotein in the absence of feline leukemia virus gag sequences

    International Nuclear Information System (INIS)

    Wheeler, E.F.; Roussel, M.F.; Hampe, A.; Walker, M.H.; Fried, V.A.; Look, A.T.; Rettenmier, C.W.; Sherr, C.J.

    1986-01-01

    The nucleotide sequence of a 5' segment of the human genomic c-fms proto-oncogene suggested that recombination between feline leukemia virus and feline c-fms sequences might have occurred in a region encoding the 5' untranslated portion of c-fms mRNA. The polyprotein precursor gP180/sup gag-fms/ encoded by the McDonough strain of feline sarcoma virus was therefore predicted to contain 34 v-fms-coded amino acids derived from sequences of the c-fms gene that are not ordinarily translated from the proto-oncogene mRNA. The (gP180/sup gag-fms/) polyprotein was cotranslationally cleaved near the gag-fms junction to remove its gag gene-coded portion. Determination of the amino-terminal sequence of the resulting v-fms-coded glycoprotein, gp120/sup v-fms/, showed that the site of proteolysis corresponded to a predicted signal peptidase cleavage site within the c-fms gene product. Together, these analyses suggested that the linked gag sequences may not be necessary for expression of a biologically active v-fms gene product. The gag-fms sequences of feline sarcoma virus strain McDonough and the v-fms sequences alone were inserted into a murine retroviral vector containing a neomycin resistance gene. The authors conclude that a cryptic hydrophobic signal peptide sequence in v-fms was unmasked by gag deletion, thereby allowing the correct orientation and transport of the v-fms was unmasked by gag deletion, thereby allowing the correct orientation and transport of the v-fms gene product within membranous organelles. It seems likely that the proteolytic cleavage of gP180/gag-fms/ is mediated by signal peptidase and that the amino termini of gp140/sup v-fms/ and the c-fms gene product are identical

  15. Effectiveness and cost-effectiveness of serum B-type natriuretic peptide testing and monitoring in patients with heart failure in primary and secondary care: an evidence synthesis, cohort study and cost-effectiveness model.

    Science.gov (United States)

    Pufulete, Maria; Maishman, Rachel; Dabner, Lucy; Mohiuddin, Syed; Hollingworth, William; Rogers, Chris A; Higgins, Julian; Dayer, Mark; Macleod, John; Purdy, Sarah; McDonagh, Theresa; Nightingale, Angus; Williams, Rachael; Reeves, Barnaby C

    2017-08-01

    Heart failure (HF) affects around 500,000 people in the UK. HF medications are frequently underprescribed and B-type natriuretic peptide (BNP)-guided therapy may help to optimise treatment. To evaluate the clinical effectiveness and cost-effectiveness of BNP-guided therapy compared with symptom-guided therapy in HF patients. Systematic review, cohort study and cost-effectiveness model. A literature review and usual care in the NHS. (a) HF patients in randomised controlled trials (RCTs) of BNP-guided therapy; and (b) patients having usual care for HF in the NHS. Systematic review : BNP-guided therapy or symptom-guided therapy in primary or secondary care. Cohort study : BNP monitored (≥ 6 months' follow-up and three or more BNP tests and two or more tests per year), BNP tested (≥ 1 tests but not BNP monitored) or never tested. Cost-effectiveness model : BNP-guided therapy in specialist clinics. Mortality, hospital admission (all cause and HF related) and adverse events; and quality-adjusted life-years (QALYs) for the cost-effectiveness model. Systematic review : Individual participant or aggregate data from eligible RCTs. Cohort study : The Clinical Practice Research Datalink, Hospital Episode Statistics and National Heart Failure Audit (NHFA). A systematic literature search (five databases, trial registries, grey literature and reference lists of publications) for published and unpublished RCTs. Five RCTs contributed individual participant data (IPD) and eight RCTs contributed aggregate data (1536 participants were randomised to BNP-guided therapy and 1538 participants were randomised to symptom-guided therapy). For all-cause mortality, the hazard ratio (HR) for BNP-guided therapy was 0.87 [95% confidence interval (CI) 0.73 to 1.04]. Patients who were aged Trust. Rachel Maishman contributed to the study when she was in receipt of a NIHR Methodology Research Fellowship.

  16. Structure-CaSR-Activity Relation of Kokumi γ-Glutamyl Peptides.

    Science.gov (United States)

    Amino, Yusuke; Nakazawa, Masakazu; Kaneko, Megumi; Miyaki, Takashi; Miyamura, Naohiro; Maruyama, Yutaka; Eto, Yuzuru

    2016-01-01

    Modulation of the calcium sensing receptor (CaSR) is one of the physiological activities of γ-glutamyl peptides such as glutathione (γ-glutamylcysteinylglycine). γ-Glutamyl peptides also possess a flavoring effect, i.e., sensory activity of kokumi substances, which modifies the five basic tastes when added to food. These activities have been shown to be positively correlated, suggesting that kokumi γ-glutamyl peptides are perceived through CaSRs in humans. Our research is based on the hypothesis that the discovery of highly active CaSR agonist peptides will lead to the creation of practical kokumi peptides. Through continuous study of the structure-CaSR-activity relation of a large number of γ-glutamyl peptides, we have determined that the structural requirements for intense CaSR activity of γ-glutamyl peptides are as follows: existence of an N-terminal γ-L-glutamyl residue; existence of a moderately sized, aliphatic, neutral substituent at the second residue in an L-configuration; and existence of a C-terminal carboxylic acid, preferably with the existence of glycine as the third constituent. By the sensory analysis of γ-glutamyl peptides selected by screening using the CaSR activity assay, γ-glutamylvalylglycine was found to be a potent kokumi peptide. Furthermore, norvaline-containing γ-glutamyl peptides, i.e., γ-glutamylnorvalylglycine and γ-glutamylnorvaline, possessed excellent sensory activity of kokumi substances. A novel, practical industrial synthesis of regiospecific γ-glutamyl peptides is also required for their commercialization, which was achieved through the ring opening reaction of N-α-carbobenzoxy-L-glutamic anhydride and amino acids or peptides in the presence of N-hydroxysuccinimide.

  17. Peptide Signals Encode Protein Localization▿

    OpenAIRE

    Russell, Jay H.; Keiler, Kenneth C.

    2007-01-01

    Many bacterial proteins are localized to precise intracellular locations, but in most cases the mechanism for encoding localization information is not known. Screening libraries of peptides fused to green fluorescent protein identified sequences that directed the protein to helical structures or to midcell. These peptides indicate that protein localization can be encoded in 20-amino-acid peptides instead of complex protein-protein interactions and raise the possibility that the location of a ...

  18. The Equine PeptideAtlas

    DEFF Research Database (Denmark)

    Bundgaard, Louise; Jacobsen, Stine; Sorensen, Mette A.

    2014-01-01

    Equine PeptideAtlas encompassing high-resolution tandem MS analyses of 51 samples representing a selection of equine tissues and body fluids from healthy and diseased animals. The raw data were processed through the Trans-Proteomic Pipeline to yield high quality identification of proteins and peptides...... analyses, and emphasizes the value of the Equine PeptideAtlas as a resource for the design of targeted quantitative proteomic studies....

  19. Structural Characterization of Peptide Antibodies

    DEFF Research Database (Denmark)

    Chailyan, Anna; Marcatili, Paolo

    2015-01-01

    The role of proteins as very effective immunogens for the generation of antibodies is indisputable. Nevertheless, cases in which protein usage for antibody production is not feasible or convenient compelled the creation of a powerful alternative consisting of synthetic peptides. Synthetic peptides...... can be modified to obtain desired properties or conformation, tagged for purification, isotopically labeled for protein quantitation or conjugated to immunogens for antibody production. The antibodies that bind to these peptides represent an invaluable tool for biological research and discovery...

  20. The Peptide Toxin Amylosin of Bacillus amyloliquefaciens from Moisture-Damaged Buildings Is Immunotoxic, Induces Potassium Efflux from Mammalian Cells, and Has Antimicrobial Activity

    Science.gov (United States)

    Teplova, Vera V.; Andersson, Maria A.; Mikkola, Raimo; Kankkunen, Päivi; Matikainen, Sampsa; Gahmberg, Carl G.; Andersson, Leif C.; Salkinoja-Salonen, Mirja

    2015-01-01

    Amylosin, a heat-stable channel-forming non-ribosomally synthesized peptide toxin produced by strains of Bacillus amyloliquefaciens isolated from moisture-damaged buildings, is shown in this paper to have immunotoxic and cytotoxic effects on human cells as well as antagonistic effects on microbes. Human macrophages exposed to 50 ng of amylosin ml−1 secreted high levels of cytokines interleukin-1β (IL-1β) and IL-18 within 2 h, indicating activation of the NLRP3 inflammasome, an integral part of the innate immune system. At the same exposure level, expression of IL-1β and IL-18 mRNA increased. Amylosin caused dose-dependent potassium ion efflux from all tested mammalian cells (human monocytes and keratinocytes and porcine sperm cells) at 1 to 2 μM exposure. Amylosin also inhibited the motility of porcine sperm cells and depolarized the mitochondria of human keratinocytes. Amylosin may thus trigger the activation of the NLRP3 inflammasome and subsequently cytokine release by causing potassium efflux from exposed cells. The results of this study indicate that exposure to amylosin activates the innate immune system, which could offer an explanation for the inflammatory symptoms experienced by occupants of moisture-damaged buildings. In addition, the amylosin-producing B. amyloliquefaciens inhibited the growth of both prokaryotic and eukaryotic indoor microbes, and purified amylosin also had an antimicrobial effect. These antimicrobial effects could make amylosin producers dominant and therefore significant causal agents of health problems in some moisture-damaged sites. PMID:25681192

  1. One Hundred Years of Peptide Chemistry

    Indian Academy of Sciences (India)

    thus a chiral center. Today, 20 amino acids are known as genetically encoded as building blocks of peptides and proteins. Almost all of them present in peptides have L-configura- tion. D-amino acids have been found only in small peptides of bacterial cell walls, peptide antibiotics and peptides in South American frog skin.

  2. Chiral Symmetry Breaking in Peptide Systems During Formation of Life on Earth

    Science.gov (United States)

    Konstantinov, Konstantin K.; Konstantinova, Alisa F.

    2018-03-01

    Chiral symmetry breaking in complex chemical systems with a large number of amino acids and a large number of similar reactions was considered. It was shown that effective averaging over similar reaction channels may result in very weak effective enantioselectivity of forward reactions, which does not allow most of the known models to result in chiral symmetry breaking during formation of life on Earth. Models with simple and catalytic synthesis of a single amino acid, formation of peptides up to length five, and sedimentation of insoluble pair of substances were considered. It was shown that depending on the model and the values of the parameters, chiral symmetry breaking may occur in up to about 10% out of all possible unique insoluble pair combinations even in the absence of any catalytic synthesis and that minimum total number of amino acids in the pair is 5. If weak enantioselective forward catalytic synthesis of amino acids is present, then the number of possible variants, in which chiral symmetry breaking may occur, increases substantially. It was shown that that the most interesting catalysts have zero or one amino acid of "incorrect" chirality. If the parameters of the model are adjusted in such a way to result in an increase of concentration of longer peptides, then catalysts with two amino acids of incorrect chirality start to appear at peptides of length five. Models of chiral symmetry breaking in the presence of epimerization were considered for peptides up to length three. It was shown that the range of parameters in which chiral symmetry breaking could occur significantly shrinks in comparison to previously considered models with peptides up to length two. An experiment of chiral symmetry breaking was proposed. The experiment consists of a three-step cycle: reversible catalytic synthesis of amino acids, reversible synthesis of peptides, and irreversible sedimentation of insoluble substances.

  3. Antimicrobial activity of analogues of a peptide isolated from venom glands of social wasps Polistes major major inhabiting the Dominican Republic

    Czech Academy of Sciences Publication Activity Database

    Ježek, Rudolf; Šebestík, Jaroslav; Šafařík, Martin; Borovičková, Lenka; Fučík, Vladimír; Čeřovský, Václav; Slaninová, Jiřina

    2008-01-01

    Roč. 14, č. 8 (2008), s. 99-99 ISSN 1075-2617. [European Peptide Symposium /30./. 31.08.2008-05.09.2008, Helsinki] Institutional research plan: CEZ:AV0Z40550506 Keywords : peptides from venom glands * Polistes major * synthesis and antimicrobial activity * analogues Subject RIV: CC - Organic Chemistry

  4. Inhibition of human immunodeficiency virus type 1 (HIV-1) penetration into target cells by synthetic peptides mimicking the N-terminus of the HIV-1 transmembrane glycoprotein

    NARCIS (Netherlands)

    Slepushkin, V. A.; Kornilaeva, G. V.; Andreev, S. M.; Sidorova, M. V.; Petrukhina, A. O.; Matsevich, G. R.; Raduk, S. V.; Grigoriev, V. B.; Makarova, T. V.; Lukashov, V. V.

    1993-01-01

    To investigate the mechanism of action of the 22-amino-acid HIV fusion peptide on HIV infection, we studied its influence on virus adsorption and HIV-induced syncytium formation. The effect of the peptide preparations on the synthesis of viral antigens in HIV-infected cell cultures was determined by

  5. Tandem ligation of unprotected peptides through thiaprolyl and cysteinyl bonds in water.

    Science.gov (United States)

    Tam, J P; Yu, Q; Yang, J L

    2001-03-21

    Tandem ligation for the synthesis and modification of proteins entails forming two or more regiospecific amide bonds of multiple free peptide segments without a protecting-group scheme. We here describe a semi-orthogonal strategy for ligating three unprotected peptide segments, two of which contain N-terminal (NT) cysteine, to form in tandem two amide bonds, an Xaa-SPro (thiaproline), and then an Xaa-Cys. This strategy exploits the strong preference of an NT-cysteinyl peptide under acidic conditions to undergo selectively an SPro-imine ligation rather than a Cys-thioester ligation. Operationally, it was performed in the N --> C direction, first by an imine ligation at pH glycoaldehyde ester and a second peptide containing both an NT-Cys and a CT-thioester. The newly created O-ester-linked segment with a CT-thioester was then ligated to another NT-cysteinyl peptide through thioester ligation at pH > 7 to form an Xaa-Cys bond. Concurrently, this basic condition also catalyzed the O,N-acyl migration of an Xaa-thiazolidine ester to the Xaa-SPro bond at the first ligation site to complete the tandem three-segment ligation. Both ligation reactions were performed in aqueous buffered solvents. The effectiveness of this three-segment ligation strategy was tested in six peptides ranging from 19 to 70 amino acids, including thiaproline --> proline analogues of somatostatins and two CC-chemokines. The thiaproline replacements in these peptides and proteins did not result in altered biological activity. By eliminating the protecting-group scheme and coupling reagents, tandem ligation of multiple free peptide segments in aqueous solutions enhances the scope of protein synthesis and may provide a useful approach for combinatorial segment synthesis.

  6. Peptide Vaccines for Cancer

    Directory of Open Access Journals (Sweden)

    Kono K

    2013-10-01

    Full Text Available Background: In general, the preferable characteristic of the target molecules for development of cancer vaccines are high immunogenicity, very common expression in cancer cells, specific expression in cancer cells and essential molecules for cell survival (to avoid loss of expression. We previously reported that three novel HLA-A24-restricted immunodominant peptides, which were derived from three different oncoantigens, TTK, LY6K, and IMP-3,were promising targets for cancer vaccination for esophageal squamous cell carcinoma (ESCCpatients. Then, we had performed a phase I clinical trial using three HLA-A24-binding peptides and the results had been shown to be promising for ESCC. Therefore, we further performed a multicenter, non-randomized phase II clinical trial. Patients and Methods: Sixty ESCC patients were enrolled to evaluate OS, PFS, immunological response employing ELISPOT and pentamer assays. Each of the three peptides was administered with IFA weekly. All patients received the vaccination without knowing an HLA-A type, and the HLA types were key-opened at the analysis point. Hence, the endpoints were set to evaluate differences between HLA-A*2402-positive (24(+ and -negative (24(- groups. Results: The OS in the 24 (+ group (n=35 tended to be better than that in the 24(- group (n=25 (MST 4.6 vs. 2.6 month, respectively, p = 0.121, although the difference was not statistically significant. However, the PFS in the 24(+ group was significantly better than that in the 24(- group (p = 0.032. In the 24(+ group, ELISPOT assay indicated that the LY6K-, TTK-, and IMP3-specific CTL responses were observed after the vaccination in 63%, 45%, and 60% of the 24(+ group, respectively. The patients having LY6K-, TTK-, and IMP3-specific CTL responses revealed the better OS than those not having CTL induction, respectively. The patients showing the CTL induction for multiple peptides have better clinical responses. Conclusion: The immune response induced

  7. Natriuretic peptides in cardiometabolic regulation and disease

    DEFF Research Database (Denmark)

    Zois, Nora E; Bartels, Emil D; Hunter, Ingrid

    2014-01-01

    these conditions can coexist and potentially lead to heart failure, a syndrome associated with a functional natriuretic peptide deficiency despite high circulating concentrations of immunoreactive peptides. Therefore, dysregulation of the natriuretic peptide system, a 'natriuretic handicap', might be an important...

  8. Radiolabeling of methionine containing proteins and peptides

    International Nuclear Information System (INIS)

    Garlick, R.K.; Jirousek, L.

    1986-01-01

    A process for radiolabeling methionine-containing peptides and proteins is disclosed. The process comprises the steps of oxidizing the protein or peptide, radiolabeling and reducing the radiolabeled protein or peptide. (author)

  9. Endogenous human milk peptide release is greater after preterm birth than term birth.

    Science.gov (United States)

    Dallas, David C; Smink, Christina J; Robinson, Randall C; Tian, Tian; Guerrero, Andres; Parker, Evan A; Smilowitz, Jennifer T; Hettinga, Kasper A; Underwood, Mark A; Lebrilla, Carlito B; German, J Bruce; Barile, Daniela

    2015-03-01

    Hundreds of naturally occurring milk peptides are present in term human milk. Preterm milk is produced before complete maturation of the mammary gland, which could change milk synthesis and secretion processes within the mammary gland, leading to differences in protein expression and enzymatic activity, thereby resulting in an altered peptide profile. This study examined differences in peptides present between milk from women delivering at term and women delivering prematurely. Nano-LC tandem mass spectrometry was employed to identify naturally occurring peptides and compare their abundances between term and preterm human milk samples at multiple time points over lactation. Term milk samples were collected from 8 mothers and preterm milk was collected from 14 mothers. The 28 preterm and 32 term human milk samples were divided into 4 groups based on day of collection (term milk. Bioinformatic analysis of the cleavage sites for peptides identified suggested that plasmin was more active in preterm milk than term milk and that cytosol aminopeptidase and carboxypeptidase B2 likely contribute to extensive milk protein breakdown. Many identified milk peptides in both term and preterm milk overlapped with known functional peptides, including antihypertensive, antimicrobial, and immunomodulatory peptides. The high protein degradation by endogenous proteases in preterm milk might attenuate problems because of the preterm infant's immature digestive system. This trial was registered at clinicaltrials.gov as NCT01817127. © 2015 American Society for Nutrition.

  10. The presence of food-derived collagen peptides in human body-structure and biological activity.

    Science.gov (United States)

    Sato, Kenji

    2017-12-13

    It has been demonstrated that the ingestion of some protein hydrolysates exerts health-promoting effects. For understanding the underlying mechanisms responsible for these effects, the identification of bioactive peptides in the target organ is crucial. For this purpose, in vitro activity-guided fractionation for peptides in the protein hydrolysate has been performed. However, the peptides in the hydrolysate may be further degraded during digestion. The concentration of the active peptides, which were identified by in vitro activity-guided fractionation, in human blood is frequently very low (nanomolar levels). In contrast, micromolar levels of food-derived collagen peptides are present in human blood. Pro-Hyp, one of the major food-derived collagen peptides, enhances the growth of fibroblasts and synthesis of hyaluronic acid. These observations partially explain the beneficial effects of collagen hydrolysate ingestion on the enhancement of wound healing and improvement in the skin condition. The recent advancement involving liquid chromatography and mass spectrometry coupled with a pre-column derivatization technique has enabled the identification of food-derived peptides at nanomolar levels in the body post-ingestion of protein hydrolysates. Thus, this technique can be used for the identification of bioactive food-derived peptides in the body.

  11. Assembly and use of high-density recombinant peptide chips for large-scale ligand screening is a practical alternative to synthetic peptide libraries.

    Science.gov (United States)

    Hundsberger, Harald; Önder, Kamil; Schuller-Götzburg, Peter; Virok, Dezso P; Herzog, Julia; Rid, Raphaela

    2017-06-08

    Recombinant peptide chips could constitute a versatile complementation to state-of-the-art in situ (chemical on-chip) synthesis, particle-based printing, or pre-manufactured peptide spotting. Bottlenecks still impeding a routine implementation - from restricted peptide lengths, low diversity and low array densities to high costs - could so be overcome. To assess overall performance, we assembled recombinant chips composed of 38,400 individual peptide spots on the area of a standard 96-well microtiter plate from comprehensive, highly diverse (>107 single clones) short random peptide libraries. Screening of altogether 476,160 clones against Streptavidin uncovered 2 discrete new binders: a characteristic HPQ-motif containing VSHPQAPF and a cyclic CSGSYGSC peptide. Interactions were technically confirmed by fluorescence polarization as well as biolayer-interferometry, and their potential suitability as novel detection tags evaluated by detection of a peptide-fused exemplary test protein. From our data we conclude that the presented technical pipeline can reliably identify novel hits, useful as first-generation binders or templates for subsequent ligand design plus engineering.

  12. Improved proteolytic stability and potent activity against Leishmania infantum trypanothione reductase of α/β-peptide foldamers conjugated to cell-penetrating peptides.

    Science.gov (United States)

    de Lucio, Héctor; Gamo, Ana María; Ruiz-Santaquiteria, Marta; de Castro, Sonia; Sánchez-Murcia, Pedro A; Toro, Miguel A; Gutiérrez, Kilian Jesús; Gago, Federico; Jiménez-Ruiz, Antonio; Camarasa, María-José; Velázquez, Sonsoles

    2017-11-10

    The objective of the current study was to enhance the proteolytic stability of peptide-based inhibitors that target critical protein-protein interactions at the dimerization interface of Leishmania infantum trypanothione reductase (Li-TryR) using a backbone modification strategy. To achieve this goal we carried out the synthesis, proteolytic stability studies and biological evaluation of a small library of α/β 3 -peptide foldamers of different length (from 9-mers to 13-mers) and different α→β substitution patterns related to prototype linear α-peptides. We show that several 13-residue α/β 3 -peptide foldamers retain inhibitory potency against the enzyme (in both activity and dimerization assays) while they are far less susceptible to proteolytic degradation than an analogous α-peptide. The strong dependence of the binding affinities for Li-TryR on the length of the α,β-peptides is supported by theoretical calculations on conformational ensembles of the resulting complexes. The conjugation of the most proteolytically stable α/β-peptide with oligoarginines results in a molecule with potent activity against L. infantum promastigotes and amastigotes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  13. Protein chemical synthesis in drug discovery.

    Science.gov (United States)

    Liu, Fa; Mayer, John P

    2015-01-01

    The discovery of novel therapeutics to combat human disease has traditionally been among the most important goals of research chemists. After a century of innovation, state-of-the-art chemical protein synthesis is now capable of efficiently assembling proteins of up to several hundred residues in length from individual amino acids. By virtue of its unique ability to incorporate non-native structural elements, chemical protein synthesis has been seminal in the recent development of several novel drug discovery technologies. In this chapter, we review the key advances in peptide and protein chemistry which have enabled our current synthetic capabilities. We also discuss the synthesis of D-proteins and their applications in mirror image phage-display and racemic protein crystallography, the synthesis of enzymes for structure-based drug discovery, and the direct synthesis of homogenous protein pharmaceuticals.

  14. Peptide radiopharmaceuticals in nuclear medicine

    International Nuclear Information System (INIS)

    Blok, D.; Vermeij, P.; Feitsma, R.I.J.; Pauwels, E.J.K.

    1999-01-01

    This article reviews the labelling of peptides that are recognised to be of interest for nuclear medicine or are the subject of ongoing nuclear medicine research. Applications and approaches to the labelling of peptide radiopharmaceuticals are discussed, and drawbacks in their development considered. (orig.)

  15. Antimicrobial peptides in the airway.

    Science.gov (United States)

    Laube, D M; Yim, S; Ryan, L K; Kisich, K O; Diamond, G

    2006-01-01

    The airway provides numerous defense mechanisms to prevent microbial colonization by the large numbers of bacteria and viruses present in ambient air. An important component of this defense is the antimicrobial peptides and proteins present in the airway surface fluid (ASF), the mucin-rich fluid covering the respiratory epithelium. These include larger proteins such as lysozyme and lactoferrin, as well as the cationic defensin and cathelicidin peptides. While some of these peptides, such as human beta-defensin (hBD)-1, are present constitutively, others, including hBD2 and -3 are inducible in response to bacterial recognition by Toll-like receptor-mediated pathways. These peptides can act as microbicides in the ASF, but also exhibit other activities, including potent chemotactic activity for cells of the innate and adaptive immune systems, suggesting they play a complex role in the host defense of the airway. Inhibition of antimicrobial peptide activity or gene expression can result in increased susceptibility to infections. This has been observed with cystic fibrosis (CF), where the CF phenotype leads to reduced antimicrobial capacity of peptides in the airway. Pathogenic virulence factors can inhibit defensin gene expression, as can environmental factors such as air pollution. Such an interference can result in infections by airway-specific pathogens including Bordetella bronchiseptica, Mycobacterium tuberculosis, and influenza virus. Research into the modulation of peptide gene expression in animal models, as well as the optimization of peptide-based therapeutics shows promise for the treatment and prevention of airway infectious diseases.

  16. Peptide-LNA oligonucleotide conjugates

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Hansen, Lykke Haastrup; Vester, Birte

    2013-01-01

    properties, peptides were introduced into oligonucleotides via a 2'-alkyne-2'-amino-LNA scaffold. Derivatives of methionine- and leucine-enkephalins were chosen as model peptides of mixed amino acid content, which were singly and doubly incorporated into LNA/DNA strands using highly efficient copper...

  17. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    N.D. Zegers (Netty)

    1995-01-01

    textabstractSynthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps

  18. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    Zegers, N.D.

    1995-01-01

    Synthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps that lead to the

  19. Urinary Peptides in Rett Syndrome.

    Science.gov (United States)

    Solaas, K. M.; Skjeldal, O.; Gardner, M. L. G.; Kase, B. F.; Reichelt, K. L.

    2002-01-01

    A study found a significantly higher level of peptides in the urine of 53 girls with Rett syndrome compared with controls. The elevation was similar to that in 35 girls with infantile autism. Levels of peptides were lower in girls with classic Rett syndrome than those with congenital Rett syndrome. (Contains references.) (Author/CR)

  20. Safe and efficient Boc-SPPS for the synthesis of glycopeptide-α-thioesters.

    Science.gov (United States)

    Izumi, Masayuki; Murakami, Masumi; Okamoto, Ryo; Kajihara, Yasuhiro

    2014-02-01

    Boc-solid phase peptide synthesis is useful for the preparation of peptide-α-thioesters. However, this strategy usually employs hydrogen fluoride for the final deprotection step. These strongly acidic conditions cannot be applied for the synthesis of acid-labile glycopeptide-α-thioesters. The protocol presented here is a modified in situ neutralization Boc-solid phase peptide synthesis employing 10% sulfuric acid/dioxane conditions for intermediate Boc removal and TfOH for the final side-chain deprotection step. These conditions were found to be applicable for the synthesis of acid-labile glycopeptide-α-thioesters. In this protocol, a glycopeptide is synthesized as α- thioester on a thiol linker, and the product glycopeptide-α-thioester is released from the resin by thiolysis after side-chain deprotection step with an acid cocktail containing TfOH instead of hydrogen fluoride. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  1. Enhanced antimicrobial activity of novel synthetic peptides derived from vejovine and hadrurin.

    Science.gov (United States)

    Sánchez-Vásquez, Lorenzo; Silva-Sanchez, Jesus; Jiménez-Vargas, Juana Maria; Rodríguez-Romero, Adela; Muñoz-Garay, Carlos; Rodríguez, Maria C; Gurrola, Georgina B; Possani, Lourival D

    2013-06-01

    Microbial antibiotic resistance is a challenging medical problem nowadays. Two scorpion peptides displaying antibiotic activity: hadrurin and vejovine were taken as models for the design of novel shorter peptides with similar activity. Using the standard Fmoc-based solid phase synthesis technique of Merrifield twelve peptides (18 to 29 amino acids long) were synthesized, purified and assayed against a variety of multi-drug resistant Gram-negative bacteria from clinical isolates. Hemolytic and antiparasitic activities of the peptides and their possible interactions with eukaryotic cells were verified. Release of the fluorophore calcein from liposomes treated with these peptides was measured. A peptide with sequence GILKTIKSIASKVANTVQKLKRKAKNAVA), and three analogs: Δ(Α29), Δ(K12-Q18; Ν26-Α29), and K4N Δ(K12-Q18; Ν26-Α29) were shown to inhibit the growth of Gram-negative (E. coli ATCC25922) and Gram-positive bacteria (S. aureus), as well as multi-drug resistant (MDR) clinical isolated. The antibacterial and antiparasitic activities were found with peptides at 0.78 to 25μM and 5 to 25μM concentration, respectively. These peptides have low cytotoxic and hemolytic activities at concentrations significantly exceeding their minimum inhibitory concentrations (MICs), showing values between 40 and 900μM for their EC50, compared to the parent peptides vejovine and hadrurin that at the same concentration of their MICs lysed more than 50% of human erythrocytes cells. These peptides promise to be good candidates to combat infections caused by Gram-negative bacteria from nosocomial infections. Our results confirm that well designed synthetic peptides can be an alternative for solving the lack of effective antibiotics to control bacterial infections. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Antioxidant activity of a novel synthetic hexa-peptide derived from an enzymatic hydrolysate of duck skin by-products.

    Science.gov (United States)

    Lee, Seung-Jae; Cheong, Sun Hee; Kim, Yon-Suk; Hwang, Jin-Woo; Kwon, Hyuck-Ju; Kang, Seo-Hee; Moon, Sang-Ho; Jeon, Byong-Tae; Park, Pyo-Jam

    2013-12-01

    A peptide was synthesized on the basis of our previous study from solid phase peptide synthesis using ASP48S (Peptron Inc.) and identified by the reverse phase high-performance liquid chromatography (HPLC) using a Vydac Everest C18 column. The molecular mass of the peptide found to be 693.90 Da, and the amino acid sequences of the peptide was Trp-Tyr-Pro-Ala-Ala-Pro. The purpose of this study was to evaluate antioxidant effects of the peptide by electron spin resonance (ESR) spectrometer, and on t-BHP-induced liver cells damage in Chang cells. The antioxidative activity of the peptide was evaluated by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, alkyl and superoxide radical scavenging activity using an ESR spectrometer. The half maximal inhibitory concentration (IC50) value of the peptide for hydroxyl, DPPH, alkyl, and superoxide radical scavenging activity were 45.2, 18.5, 31.5, and 33.4 μM, respectively. In addition, the peptide inhibited productions of cell death against t-BHP-induced liver cell damage in Chang cells. It was presumed to be peptide involved in regulating the apoptosis-related gene expression in the cell environment. The present results indicate that the peptide substantially contributes to antioxidative properties in liver cells. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Maize Bioactive Peptides against Cancer

    Science.gov (United States)

    Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio

    2017-06-01

    Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derived food products has been associated with reduction risks of various types of cancer. Cereals main biomolecules includes proteins, peptides, and amino acids present in different quantities within the grain. The nutraceutical properties associated with peptides exerts biological functions that promote health and prevent this disease. In this review, we report the current status and advances on maize peptides regarding bioactive properties that have been reported such as antioxidant, antihypertensive, hepatoprotective, and anti-tumour activities. We also highlighted its biological potential through which maize bioactive peptides exert anti-cancer activity. Finally, we analyse and emphasize the possible areas of application for maize peptides.

  4. Total chemical synthesis of proteins without HPLC purification.

    Science.gov (United States)

    Loibl, S F; Harpaz, Z; Zitterbart, R; Seitz, O

    2016-11-01

    The total chemical synthesis of proteins is a tedious and time-consuming endeavour. The typical steps involve solid phase synthesis of peptide thioesters and cysteinyl peptides, native chemical ligation (NCL) in solution, desulfurization or removal of ligation auxiliaries in the case of extended NCL as well as many intermediary and final HPLC purification steps. With an aim to facilitate and improve the throughput of protein synthesis we developed the first method for the rapid chemical total on-resin synthesis of proteins that proceeds without a single HPLC-purification step. The method relies on the combination of three orthogonal protein tags that allow sequential immobilization ( via the N-terminal and C-terminal ends), extended native chemical ligation and release reactions. The peptide fragments to be ligated are prepared by conventional solid phase synthesis and used as crude materials in the subsequent steps. An N-terminal His 6 unit permits selective immobilization of the full length peptide thioester onto Ni-NTA agarose beads. The C-terminal peptide fragment carries a C-terminal peptide hydrazide and an N-terminal 2-mercapto-2-phenyl-ethyl ligation auxiliary, which serves as a reactivity tag for the full length peptide. As a result, only full length peptides, not truncation products, react in the subsequent on-bead extended NCL. After auxiliary removal the ligation product is liberated into solution upon treatment with mild acid, and is concomitantly captured by an aldehyde-modified resin. This step allows the removal of the most frequently observed by-product in NCL chemistry, i.e. the hydrolysed peptide thioester (which does not contain a C-terminal peptide hydrazide). Finally, the target protein is released with diluted hydrazine or acid. We applied the method in the synthesis of 46 to 126 amino acid long MUC1 proteins comprising 2-6 copies of a 20mer tandem repeat sequence. Only three days were required for the parallel synthesis of 9 MUC1 proteins

  5. Folding Topology of a Short Coiled-Coil Peptide Structure Templated by an Oligonucleotide Triplex

    DEFF Research Database (Denmark)

    Lou, Chenguang; Christensen, Niels Johan; Martos Maldonado, Manuel Cristo

    2017-01-01

    by oligonucleotide duplex and triplex formation. POC synthesis was achieved by copper-free alkyne-azide cycloaddition between three oligonucleotides and a 23-mer peptide, which by itself exhibited multiple oligomeric states in solution. The oligonucleotide domain was designed to furnish a stable parallel triplex...

  6. Selective chromogenic and fluorogenic peptide substrates for the assay of cysteine peptidases in complex mixtures

    Science.gov (United States)

    Cysteine peptidases are important in many biological processes. In this study, we describe the design, synthesis and use of selective peptide substrates for cysteine peptidases of the C1 papain family. The structure of the proposed substrates can be expressed by the general formula Glp-Xaa-Ala-Y, wh...

  7. Endogenous human milk Peptide release is greater after preterm birth than term birth

    NARCIS (Netherlands)

    Dallas, D.C.; Smink, C.J.; Robinson, R.C.; Tian, T.; Guerrero, A.; Parker, E.A.; Smilowitz, J.T.; Hettinga, K.A.; Underwood, M.A.; Lebrilla, C.B.; German, J.B.; Barile, D.

    2015-01-01

    Background: Hundreds of naturally occurring milk peptides are present in term human milk. Preterm milk is produced before complete maturation of the mammary gland, which could change milk synthesis and secretion processes within the mammary gland, leading to differences in protein expression and

  8. Metabolic cleavage of cell-penetrating peptides in contact with epithelial models

    DEFF Research Database (Denmark)

    Tréhin, Rachel; Nielsen, Hanne Mørck; Jahnke, Heinz-Georg

    2004-01-01

    We assessed the metabolic degradation kinetics and cleavage patterns of some selected CPP (cell-penetrating peptides) after incubation with confluent epithelial models. Synthesis of N-terminal CF [5(6)-carboxyfluorescein]-labelled CPP, namely hCT (human calcitonin)-derived sequences, Tat(47...

  9. Multitasking antimicrobial peptides, plant development, and host defense against biotic/abiotic stress

    Science.gov (United States)

    Crop losses due to pathogens are a major threat to global food security. Plants employ a multilayer defense system against pathogens including use of physical barriers (cell wall), induction of hypersensitive defense response (HR), resistance (R) proteins, and synthesis of antimicrobial peptides (AM...

  10. Biosynthesis of amidated joining peptide from pro-adrenocorticotropin-endorphin

    Energy Technology Data Exchange (ETDEWEB)

    Cullen, E.I.; Mains, R.E. (Johns Hopkins Univ. School of Medicine, Baltimore, MD (USA))

    1987-09-01

    Joining peptide is the major alpha-amidated product of pro-ACTH/endorphin (PAE) in AtT-20 corticotropic tumor cells. To study intracellular joining peptide synthesis, affinity purified antibodies directed against gamma-MSH, joining peptide, and ACTH were used to immunoprecipitate extracts from biosynthetically labeled AtT-20 cells. Immunoprecipitates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by tryptic peptide mapping on HPLC. In steady labeling experiments, radioactivity in amidated joining peptide (JP) increased roughly linearly with time, in the manner of a final product, whereas radioactivity associated with PAE (1-94)NH2 reached a constant value after 2-4 h, indicating that PAE(1-94)NH2 is an intermediate in the biosynthesis of JP. Radioactivity appeared in ACTH(1-39) well before JP, consistent with a cleavage order in which ACTH is cleaved from PAE(1-95) before JP sequences are cleaved from PAE(1-74). This conclusion was supported by tryptic peptide analyses of immunoprecipitates, which indicated that less than 5% of JP-related material is cleaved from PAE(1-74) before being cleaved from ACTH-related sequences. After a pulse label, radioactivity in PAE(1-94)NH2 reached a peak value after 1 h of chase and declined with a half-life of less than 1 h. Amidated JP increased to a constant level after 2 h of chase. Enough radiolabeled PAE(1-94)NH2 was detected to account for about half of the radioactivity found in amidated JP, indicating that about half of JP-related material is first cleaved from PAE(1-95) before being amidated. This result was corroborated using HPLC purification to determine both amidated and glycine-extended forms of JP.

  11. Cathepsin-Mediated Cleavage of Peptides from Peptide Amphiphiles Leads to Enhanced Intracellular Peptide Accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Acar, Handan [Institute; Department; Samaeekia, Ravand [Institute; Department; Schnorenberg, Mathew R. [Institute; Department; Medical; Sasmal, Dibyendu K. [Institute; Huang, Jun [Institute; Tirrell, Matthew V. [Institute; Institute; LaBelle, James L. [Department

    2017-08-24

    Peptides synthesized in the likeness of their native interaction domain(s) are natural choices to target protein protein interactions (PPIs) due to their fidelity of orthostatic contact points between binding partners. Despite therapeutic promise, intracellular delivery of biofunctional peptides at concentrations necessary for efficacy remains a formidable challenge. Peptide amphiphiles (PAs) provide a facile method of intracellular delivery and stabilization of bioactive peptides. PAs consisting of biofunctional peptide headgroups linked to hydrophobic alkyl lipid-like tails prevent peptide hydrolysis and proteolysis in circulation, and PA monomers are internalized via endocytosis. However, endocytotic sequestration and steric hindrance from the lipid tail are two major mechanisms that limit PA efficacy to target intracellular PPIs. To address these problems, we have constructed a PA platform consisting of cathepsin-B cleavable PAs in which a selective p53-based inhibitory peptide is cleaved from its lipid tail within endosomes, allowing for intracellular peptide accumulation and extracellular recycling of the lipid moiety. We monitor for cleavage and follow individual PA components in real time using a resonance energy transfer (FRET)-based tracking system. Using this platform, components in real time using a Forster we provide a better understanding and quantification of cellular internalization, trafficking, and endosomal cleavage of PAs and of the ultimate fates of each component.

  12. Immobilization methods for the rapid total chemical synthesis of proteins on microtiter plates.

    Science.gov (United States)

    Zitterbart, Robert; Krumrey, Michael; Seitz, Oliver

    2017-07-01

    The chemical synthesis of proteins typically involves the solid-phase peptide synthesis of unprotected peptide fragments that are stitched together in solution by native chemical ligation (NCL). The process is slow, and throughput is limited because of the need for repeated high performance liquid chromatography purification steps after both solid-phase peptide synthesis and NCL. With an aim to provide faster access to functional proteins and to accelerate the functional analysis of synthetic proteins by parallelization, we developed a method for the high performance liquid chromatography-free synthesis of proteins on the surface of microtiter plates. The method relies on solid-phase synthesis of unprotected peptide fragments, immobilization of the C-terminal fragment and on-surface NCL with an unprotected peptide thioester in crude form. Herein, we describe the development of a suitable immobilization chemistry. We compared (i) formation of nickel(II)-oligohistidine complexes, (ii) Cu-based [2 + 3] alkine-azide cycloaddition and (iii) hydrazone ligation. The comparative study identified the hydrazone ligation as most suitable. The sequence of immobilization via hydrazone ligation, on-surface NCL and radical desulfurization furnished the targeted SH3 domains in near quantitative yield. The synthetic proteins were functional as demonstrated by an on-surface fluorescence-based saturation binding analysis. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

  13. Chemical Protein Synthesis with the α-Ketoacid-Hydroxylamine Ligation.

    Science.gov (United States)

    Bode, Jeffrey W

    2017-09-19

    The coupling of an α-ketoacid and a hydroxylamine (KAHA ligation) affords amide bonds under aqueous, acidic conditions without the need for protecting groups or coupling agents. Translating this finding into a general approach to chemical protein synthesis required the identification of methods to incorporate the key functional groups into unprotected peptide segments-ideally using well-established Fmoc solid-phase peptide synthesis protocols. A decade of effort has now led to robust, convenient methods for preparing peptides bearing free or masked C-terminal α-ketoacids and N-terminal hydroxylamines. The facile synthesis of the segments and the aqueous, acidic conditions of the KAHA ligation make it ideal for the construction of small proteins (up to 200 residues), including SUMO and related modifier proteins, betatrophin and other protein hormones, nitrophorin 4, S100A4, and the cyclic protein AS-48. Key to the successful development of this protein synthesis platform was the identification and gram-scale synthesis of (S)-5-oxaproline. This hydroxylamine monomer is completely stable toward standard methods and practices of solid-phase peptide synthesis while still performing very well in the KAHA ligation. This reaction partner-in contrast to all others examined-affords esters rather than amides as the primary ligation product. The resulting depsipeptides often offer superior solubility and handling and have been key in the chemical synthesis of hydrophobic and ampiphilic proteins. Upon facile O-to-N acyl shift, peptides bearing a noncanonical homoserine residue at the ligation site are formed. With proper choice of the ligation site, the incorporation of this unnatural amino acid does not appear to affect the structure or biological activity of the protein targets. The development of the chemical methods for preparing and masking peptide α-ketoacids and hydroxyalmines, the preparation of several protein targets by convergent ligation strategies, and the

  14. Enzyme-triggered compound release using functionalized antimicrobial peptide derivatives.

    Science.gov (United States)

    Mizukami, Shin; Kashibe, Masayoshi; Matsumoto, Kengo; Hori, Yuichiro; Kikuchi, Kazuya

    2017-04-01

    Controlled release is one of the key technologies for medical innovation, and many stimulus-responsive nanocarriers have been developed to utilize this technology. Enzyme activity is one of the most useful stimuli, because many enzymes are specifically activated in diseased tissues. However, controlled release stimulated by enzyme activity has not been frequently reported. One of the reasons for this is the lack of versatility of carriers. Most of the reported stimulus-responsive systems involve a sophisticated design and a complicated process for the synthesis of stimulus-responsive nanocarrier components. The purpose of this study was to develop versatile controlled release systems triggered by various stimuli, including enzyme activity, without modifying the nanocarrier components. We developed two controlled release systems, both of which comprised a liposome as the nanocarrier and a membrane-damaging peptide, temporin L (TL), and its derivatives as the release-controllers. One system utilized branched peptides for proteases, and the other utilized phosphopeptides for phosphatases. In our systems, the target enzymes converted the non-membrane-damaging TL derivatives into membrane-damaging peptides and released the liposome inclusion. We demonstrated the use of our antimicrobial peptide-based controlled release systems for different enzymes and showed the promise of this technology as a novel theranostic tool.

  15. Chemical synthesis and biophysical applications of membrane proteins.

    Science.gov (United States)

    Zuo, Chao; Tang, Shan; Zheng, Ji-Shen

    2015-07-01

    Chemical synthesis or semi-synthesis of membrane proteins can provide unique molecular tools, such as site-specific isotope labeling or post-translationally modified membrane proteins to gain insight into their biophysical and functional characteristics. However, during preparation, purification, and ligation of transmembrane peptides, tremendous challenges are encountered owing to their hydrophobic nature. This review focuses on the recent advances in chemical synthesis strategies of membrane proteins. These strategies help to solubilize the hydrophobic transmembrane peptide sequences under standard purification and chemical ligation conditions to improve their handling properties. Biophysical and functional studies of synthetic membrane proteins are reviewed as well. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  16. Delivery systems for antimicrobial peptides

    DEFF Research Database (Denmark)

    Nordström, Randi; Malmsten, Martin

    2017-01-01

    on the identification such peptides, as well as on their optimization to reach potent antimicrobial and anti-inflammatory effects at simultaneously low toxicity against human cells. In comparison, delivery systems for antimicrobial peptides have attracted considerably less interest. However, such delivery systems......, or through achieving co-localization with intracellular pathogens. Here, an overview is provided of the current understanding of delivery systems for antimicrobial peptides, with special focus on AMP-carrier interactions, as well as consequences of these interactions for antimicrobial and related biological...

  17. Identification of Functional Peptide Sequences to Lead the Design of Precision Polymers.

    Science.gov (United States)

    Ten Brummelhuis, Niels; Wilke, Patrick; Börner, Hans G

    2017-12-01

    Peptide sciences developed dramatically as a result of routine use of solid-phase peptide synthesis and nowadays offer a rich set of well-established strategies to design and identify functional peptide sequences for advanced applications in materials sciences. Appropriate sequences for a wide range of interesting material targets, ranging from molecules to materials surfaces and internal interfaces, can be selected via combinatorial means, and sequence specificities within the resulting peptide-target interactions can be routinely investigated. Based on this understanding, macromolecular sciences can define new polymer structures that meet required functionalities or functional sequences with fully synthetic, nonpeptidic precision polymers to endeavor toward information-based design of next-generation, purpose-adapted macromolecules. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. 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.

  19. Molecular architecture with carbohydrate functionalized β-peptides adopting 314-helical conformation

    Directory of Open Access Journals (Sweden)

    Nitin J. Pawar

    2014-04-01

    Full Text Available Carbohydrate recognition is essential in cellular interactions and biological processes. It is characterized by structural diversity, multivalency and cooperative effects. To evaluate carbohydrate interaction and recognition, the structurally defined attachment of sugar units to a rigid template is highly desired. β-Peptide helices offer conformationally stable templates for the linear presentation of sugar units in defined distances. The synthesis and β-peptide incorporation of sugar-β-amino acids are described providing the saccharide units as amino acid side chain. The respective sugar-β-amino acids are accessible by Michael addition of ammonia to sugar units derivatized as α,β-unsaturated esters. Three sugar units were incorporated in β-peptide oligomers varying the sugar (glucose, galactose, xylose and sugar protecting groups. The influence of sugar units and the configuration of sugar-β-amino acids on β-peptide secondary structure were investigated by CD spectroscopy.

  20. Highly Potent Antibacterial Organometallic Peptide Conjugates.

    Science.gov (United States)

    Albada, Bauke; Metzler-Nolte, Nils

    2017-10-17

    Resistance of pathogenic bacteria against currently marketed antibiotics is again increasing. To meet the societal need for effective cures, scientists are faced with the challenge of developing more potent but equally bacteria-specific drugs. Currently, most efforts are directed toward the modification of existing antibiotics, but ideally, compounds with a new mode of action are required. In this Account, we detail our findings in the area of novel metal-based antibiotics. Our strategy is based on the modification of simple antimicrobial peptides (AMPs) with organometallic agents, resulting in organometallic AMPs (OM-AMPs). Since bacteria have most likely never encountered these synthetically prepared unnatural organometallic agents, we anticipated that such agents could well become potentiating players in the antibiotics arena. Moreover, exploiting some of the particular properties of metal complexes should also help to elucidate the mode of action of small cationic AMPs, the molecular details of which have remained elusive despite intensive efforts. Using standard Fmoc/tBu-based solid-phase peptide synthesis approaches, we have prepared various organometallic-peptide conjugates with covalently linked group 8 and 9 metallocenes (ferrocene, ruthenocene, osmocene, and cobaltocenium). As a starting point we took the (RW) 3 antibacterial hexapeptide lead structure. After modifying the peptide sequence (generations 1 and 2), changing the nature and position of the organometallic group (generation 3), and optimizing the amino acid chirality (generation 5), we identified several organometallic antibacterial peptides that are currently among the most active synthetic AMPs (synAMPs) that have ever been prepared. Through these rational and systematic optimizations, we were able to increase the antibacterial activity of a short non-organometallic synAMP 18-fold to submicromolar activity, rivaling the activity of vancomycin (often the drug of last resort) against methicillin

  1. Solid-Phase Parallel Synthesis of Functionalised Medium-to-Large Cyclic Peptidomimetics through Three-Component Coupling Driven by Aziridine Aldehyde Dimers.

    Science.gov (United States)

    Treder, Adam P; Hickey, Jennifer L; Tremblay, Marie-Claude J; Zaretsky, Serge; Scully, Conor C G; Mancuso, John; Doucet, Annie; Yudin, Andrei K; Marsault, Eric

    2015-06-15

    The first solid-phase parallel synthesis of macrocyclic peptides using three-component coupling driven by aziridine aldehyde dimers is described. The method supports the synthesis of 9- to 18-membered aziridine-containing macrocycles, which are then functionalized by nucleophilic opening of the aziridine ring. This constitutes a robust approach for the rapid parallel synthesis of macrocyclic peptides. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Chagas disease-specific antigens: characterization of epitopes in CRA/FRA by synthetic peptide mapping and evaluation by ELISA-peptide assay.

    Science.gov (United States)

    Bottino, Carolina G; Gomes, Luciano P; Pereira, José B; Coura, José R; Provance, David William; De-Simone, Salvatore G

    2013-12-03

    The identification of epitopes in proteins recognized by medically relevant antibodies is useful for the development of peptide-based diagnostics and vaccines. In this study, epitopes in the cytoplasmic repetitive antigen (CRA) and flagellar repetitive antigen (FRA) proteins from Trypanosoma cruzi were identified using synthetic peptide techniques and pooled sera from Chagasic patients. The epitopes were further assayed with an ELISA assay based on synthetic peptides. Twenty-two overlapping synthetic peptides representing the coding sequence of the T. cruzi CRA and FRA proteins were assessed by a Spot-synthesis array analysis using sera donated by patients with Chagas disease. Shorter peptides were selected that represented the determined epitopes and synthesized by solid phase synthesis to evaluate the patterns of cross-reactivities and discrimination through an ELISA-diagnostic assay. The peptide Spot-synthesis array successfully identified two IgG antigenic determinants in the CRA protein and four in FRA. Bioinformatics suggested that the CRA antigens were unique to T. cruzi while the FRA antigen showed similarity with sequences present within various proteins from Leishmania sp. Subsequently, shorter peptides representing the CRA-1, CRA-2 and FRA-1 epitopes were synthesized by solid phase synthesis and assayed by an ELISA-diagnostic assay. The CRA antigens gave a high discrimination between Chagasic, Leishmaniasis and T. cruzi-uninfected serum. A sensitivity and specificity of 100% was calculated for CRA. While the FRA antigen showed a slightly lower sensitivity (91.6%), its specificity was only 60%. The epitopes recognized by human anti-T. cruzi antibodies have been precisely located in two biomarkers of T. cruzi, CRA and FRA. The results from screening a panel of patient sera through an ELISA assay based on peptides representing these epitopes strongly suggest that the sequences from CRA would be useful for the development of diagnostic reagents that could

  3. Chagas disease-specific antigens: characterization of epitopes in CRA/FRA by synthetic peptide mapping and evaluation by ELISA-peptide assay

    Science.gov (United States)

    2013-01-01

    Background The identification of epitopes in proteins recognized by medically relevant antibodies is useful for the development of peptide-based diagnostics and vaccines. In this study, epitopes in the cytoplasmic repetitive antigen (CRA) and flagellar repetitive antigen (FRA) proteins from Trypanosoma cruzi were identified using synthetic peptide techniques and pooled sera from Chagasic patients. The epitopes were further assayed with an ELISA assay based on synthetic peptides. Methods Twenty-two overlapping synthetic peptides representing the coding sequence of the T. cruzi CRA and FRA proteins were assessed by a Spot-synthesis array analysis using sera donated by patients with Chagas disease. Shorter peptides were selected that represented the determined epitopes and synthesized by solid phase synthesis to evaluate the patterns of cross-reactivities and discrimination through an ELISA-diagnostic assay. Results The peptide Spot-synthesis array successfully identified two IgG antigenic determinants in the CRA protein and four in FRA. Bioinformatics suggested that the CRA antigens were unique to T. cruzi while the FRA antigen showed similarity with sequences present within various proteins from Leishmania sp. Subsequently, shorter peptides representing the CRA-1, CRA-2 and FRA-1 epitopes were synthesized by solid phase synthesis and assayed by an ELISA-diagnostic assay. The CRA antigens gave a high discrimination between Chagasic, Leishmaniasis and T. cruzi-uninfected serum. A sensitivity and specificity of 100% was calculated for CRA. While the FRA antigen showed a slightly lower sensitivity (91.6%), its specificity was only 60%. Conclusions The epitopes recognized by human anti-T. cruzi antibodies have been precisely located in two biomarkers of T. cruzi, CRA and FRA. The results from screening a panel of patient sera through an ELISA assay based on peptides representing these epitopes strongly suggest that the sequences from CRA would be useful for the

  4. Inhibition of Henipavirus fusion and infection by heptad-derived peptides of the Nipah virus fusion glycoprotein

    Science.gov (United States)

    Bossart, Katharine N; Mungall, Bruce A; Crameri, Gary; Wang, Lin-Fa; Eaton, Bryan T; Broder, Christopher C

    2005-01-01

    Background The recent emergence of four new members of the paramyxovirus family has heightened the awareness of and re-energized research on new and emerging diseases. In particular, the high mortality and person to person transmission associated with the most recent Nipah virus outbreaks, as well as the very recent re-emergence of Hendra virus, has confirmed the importance of developing effective therapeutic interventions. We have previously shown that peptides corresponding to the C-terminal heptad repeat (HR-2) of the fusion envelope glycoprotein of Hendra virus and Nipah virus were potent inhibitors of both Hendra virus and Nipah virus-mediated membrane fusion using recombinant expression systems. In the current study, we have developed shorter, second generation HR-2 peptides which include a capped peptide via amidation and acetylation and two poly(ethylene glycol)-linked (PEGylated) peptides, one with the PEG moity at the C-terminus and the other at the N-terminus. Here, we have evaluated these peptides as well as the corresponding scrambled peptide controls in Nipah virus and Hendra virus-mediated membrane fusion and against infection by live virus in vitro. Results Unlike their predecessors, the second generation HR-2 peptides exhibited high solubility and improved synthesis yields. Importantly, both Nipah virus and Hendra virus-mediated fusion as well as live virus infection were potently inhibited by both capped and PEGylated peptides with IC50 concentrations similar to the original HR-2 peptides, whereas the scrambled modified peptides had no inhibitory effect. These data also indicate that these chemical modifications did not alter the functional properties of the peptides as inhibitors. Conclusion Nipah virus and Hendra virus infection in vitro can be potently blocked by specific HR-2 peptides. The improved synthesis and solubility characteristics of the second generation HR-2 peptides will facilitate peptide synthesis for pre-clinical trial

  5. Inhibition of Henipavirus fusion and infection by heptad-derived peptides of the Nipah virus fusion glycoprotein

    Directory of Open Access Journals (Sweden)

    Eaton Bryan T

    2005-07-01

    Full Text Available Abstract Background The recent emergence of four new members of the paramyxovirus family has heightened the awareness of and re-energized research on new and emerging diseases. In particular, the high mortality and person to person transmission associated with the most recent Nipah virus outbreaks, as well as the very recent re-emergence of Hendra virus, has confirmed the importance of developing effective therapeutic interventions. We have previously shown that peptides corresponding to the C-terminal heptad repeat (HR-2 of the fusion envelope glycoprotein of Hendra virus and Nipah virus were potent inhibitors of both Hendra virus and Nipah virus-mediated membrane fusion using recombinant expression systems. In the current study, we have developed shorter, second generation HR-2 peptides which include a capped peptide via amidation and acetylation and two poly(ethylene glycol-linked (PEGylated peptides, one with the PEG moity at the C-terminus and the other at the N-terminus. Here, we have evaluated these peptides as well as the corresponding scrambled peptide controls in Nipah virus and Hendra virus-mediated membrane fusion and against infection by live virus in vitro. Results Unlike their predecessors, the second generation HR-2 peptides exhibited high solubility and improved synthesis yields. Importantly, both Nipah virus and Hendra virus-mediated fusion as well as live virus infection were potently inhibited by both capped and PEGylated peptides with IC50 concentrations similar to the original HR-2 peptides, whereas the scrambled modified peptides had no inhibitory effect. These data also indicate that these chemical modifications did not alter the functional properties of the peptides as inhibitors. Conclusion Nipah virus and Hendra virus infection in vitro can be potently blocked by specific HR-2 peptides. The improved synthesis and solubility characteristics of the second generation HR-2 peptides will facilitate peptide synthesis for pre

  6. Characterization of Synthetic Peptides by Mass Spectrometry.

    Science.gov (United States)

    Prabhala, Bala K; Mirza, Osman; Højrup, Peter; Hansen, Paul R

    2015-01-01

    Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI-TOF-MS and LC-MS of synthetic peptides.

  7. δ-Peptides from RuAAC-Derived 1,5-Disubstituted Triazole Units

    KAUST Repository

    Johansson, Johan R.

    2014-02-14

    Non-natural peptides with structures and functions similar to natural peptides have emerged lately in biomedical as well as nanotechnological contexts. They are interesting for pharmaceutical applications since they can adopt structures with new targeting potentials and because they are generally not prone to degradation by proteases. We report here a new set of peptidomimetics derived from δ-peptides, consisting of n units of a 1,5-disubstituted 1,2,3-triazole amino acid (5Tzl). The monomer was prepared using ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) chemistry using [RuCl2Cp]x as the catalyst, allowing for simpler purification and resulting in excellent yields. This achiral monomer was used to prepare peptide oligomers that are water soluble independent of peptide chain length. Conformational analysis and structural investigations of the oligomers were performed by 2D NOESY NMR experiments, and by quantum chemical calculations using the ωB97X-D functional. These data indicate that several conformations may co-exist with slight energetic differences. Together with their increased hydrophilicity, this feature of homo-5Tzl may prove essential for mimicking natural peptides composed of α-amino acids, where the various secondary structures are achieved by side chain effects and not by the rigidity of the peptide backbone. The improved synthetic method allows for facile variation of the 5Tzl amino acid side chains, further increasing the versatility of these compounds. A new set of non-natural peptides composed of 1,5-disubstituted 1,2,3-triazole amino acids is presented. These peptides benefit from: a) modular synthesis of the monomers, allowing variation of the side chains; b) increased solubility of the oligomers in water, irrespective of peptide length; c) flexibility of the backbone allowing these foldamers to adopt several conformations. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. The 4-pyridylmethyl ester as a protecting group for glutamic and aspartic acids: 'flipping' peptide charge states for characterization by positive ion mode ESI-MS.

    Science.gov (United States)

    Garapati, Sriramya; Burns, Colin S

    2014-03-01

    Use of the 4-pyridylmethyl ester group for side-chain protection of glutamic acid residues in solid-phase peptide synthesis enables switching of the charge state of a peptide from negative to positive, thus making detection by positive ion mode ESI-MS possible. The pyridylmethyl ester moiety is readily removed from peptides in high yield by hydrogenation. Combining the 4-pyridylmethyl ester protecting group with benzyl ester protection reduces the number of the former needed to produce a net positive charge and allows for purification by RP HPLC. This protecting group is useful in the synthesis of highly acidic peptide sequences, which are often beset by problems with purification by standard RP HPLC and characterization by ESI-MS. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  9. Genetic and biochemical analysis of peptide transport in Escherichia coli

    International Nuclear Information System (INIS)

    Andrews, J.C.

    1986-01-01

    E. coli peptide transport mutants have been isolated based on their resistance to toxic tripeptides. These genetic defects were found to map in two distinct chromosomal locations. The transport systems which require expression of the trp-linked opp genes and the oppE gene(s) for activity were shown to have different substrate preferences. Growth of E. coli in medium containing leucine results in increased entry of exogenously supplied tripeptides into the bacterial cell. This leucine-mediated elevation of peptide transport required expression of the trp-linked opp operon and was accompanied by increased sensitivity to toxic tripeptides, by an enhanced capacity to utilize nutritional peptides, and by an increase in both the velocity and apparent steady-state level of L-(U- 14 C)alanyl-L-alanyl-L-alanine accumulation for E. coli grown in leucine-containing medium relative to these parameters of peptide transport measured with bacteria grown in media lacking leucine. Direct measurement of opp operon expression by pulse-labeling experiments demonstrated that growth of E. coli in the presence of leucine resulted in increased synthesis of the oppA-encoded periplasmic binding protein. The transcriptional regulation of the trp-linked opp operon of E. coli was investigated using λ placMu51-generated lac operon fusions. Synthesis of β-galactosidase by strains harboring oppA-lac, oppB-lac, and oppD-lac fusions occurred at a basal level when the fusion-containing strains were grown in minimal medium

  10. Neuroactive Peptides as Putative Mediators of Antiepileptic Ketogenic Diets

    Science.gov (United States)

    Giordano, Carmela; Marchiò, Maddalena; Timofeeva, Elena; Biagini, Giuseppe

    2014-01-01

    mechanisms involved in the beneficial effects of KDs. In this review, we summarize the current evidence for altered regulation of the synthesis of neuropeptides and peripheral hormones in response to KDs, and we try to define a possible role for specific neuroactive peptides in mediating the antiepileptic properties of diet-induced ketogenesis. PMID:24808888

  11. Neoglycolipidation for modulating peptide properties

    DEFF Research Database (Denmark)

    van Witteloostuijn, Søren Blok

    regulation of appetite, food intake, and glucose homeostasis, and many of these peptides display a signicant potential for treatment of obesity and/or type 2 diabetes. This Ph.D. thesis describes three novel approaches for utilizing gut peptides as the starting point for developing obesity and diabetes drugs....... Subsequent stereological analyses of the pancreata showed that chronic treatment with GUB06-046 led to increased cell mass in db/db mice. The results of projects I and II clearly illustrate how chemical modications can improve the pharmacological properties of native peptides. Collectively, the ndings...... of this thesis contribute to emphasize the tremendous therapeutic potential of gut peptides for treatment of obesity and diabetes....

  12. New vasoactive peptides in cirrhosis

    DEFF Research Database (Denmark)

    Kimer, Nina; Goetze, Jens Peter; Bendtsen, Flemming

    2014-01-01

    BACKGROUND: Patients with cirrhosis have substantial circulatory imbalance between vasoconstrictive and vasodilating forces. The study of circulatory vasoactive peptides may provide important pathophysiological information. This study aimed to assess concentrations, organ extraction and relations...

  13. Moonlighting peptides with emerging function.

    Directory of Open Access Journals (Sweden)

    Jonathan G Rodríguez Plaza

    Full Text Available Hunter-killer peptides combine two activities in a single polypeptide that work in an independent fashion like many other multi-functional, multi-domain proteins. We hypothesize that emergent functions may result from the combination of two or more activities in a single protein domain and that could be a mechanism selected in nature to form moonlighting proteins. We designed moonlighting peptides using the two mechanisms proposed to be involved in the evolution of such molecules (i.e., to mutate non-functional residues and the use of natively unfolded peptides. We observed that our moonlighting peptides exhibited two activities that together rendered a new function that induces cell death in yeast. Thus, we propose that moonlighting in proteins promotes emergent properties providing a further level of complexity in living organisms so far unappreciated.

  14. Composition and method for self-assembly and mineralization of peptide amphiphiles

    Science.gov (United States)

    Stupp, Samuel I [Chicago, IL; Beniash, Elia [Newton, MA; Hartgerink, Jeffrey D [Houston, TX

    2009-06-30

    The present invention is directed to a composition useful for making homogeneously mineralized self assembled peptide-amphiphile nanofibers and nanofiber gels. The composition is generally a solution comprised of a positively or negatively charged peptide-amphiphile and a like signed ion from the mineral. Mixing this solution with a second solution containing a dissolved counter-ion of the mineral and/or a second oppositely charged peptide amphiphile, results in the rapid self assembly of the peptide-amphiphiles into a nanofiber gel and templated mineralization of the ions. Templated mineralization of the initially dissolved mineral cations and anions in the mixture occurs with preferential orientation of the mineral crystals along the fiber surfaces within the nanofiber gel. One advantage of the present invention is that it results in homogenous growth of the mineral throughout the nanofiber gel. Another advantage of the present invention is that the nanofiber gel formation and mineralization reactions occur in a single mixing step and under substantially neutral or physiological pH conditions. These homogeneous nanostructured composite materials are useful for medical applications especially the regeneration of damaged bone in mammals. This invention is directed to the synthesis of peptide-amphiphiles with more than one amphiphilic moment and to supramolecular compositions comprised of such multi-dimensional peptide-amphiphiles. Supramolecular compositions can be formed by self assembly of multi-dimensional peptide-amphiphiles by mixing them with a solution comprising a monovalent cation.

  15. Composition and method for self-assembly and mineralization of peptide-amphiphiles

    Science.gov (United States)

    Stupp, Samuel I [Chicago, IL; Beniash, Elia [Newton, MA; Hartgerink, Jeffrey D [Pearland, TX

    2012-02-28

    The present invention is directed to a composition useful for making homogeneously mineralized self assembled peptide-amphiphile nanofibers and nanofiber gels. The composition is generally a solution comprised of a positively or negatively charged peptide-amphiphile and a like signed ion from the mineral. Mixing this solution with a second solution containing a dissolved counter-ion of the mineral and/or a second oppositely charged peptide amphiphile, results in the rapid self assembly of the peptide-amphiphiles into a nanofiber gel and templated mineralization of the ions. Templated mineralization of the initially dissolved mineral cations and anions in the mixture occurs with preferential orientation of the mineral crystals along the fiber surfaces within the nanofiber gel. One advantage of the present invention is that it results in homogenous growth of the mineral throughout the nanofiber gel. Another advantage of the present invention is that the nanofiber gel formation and mineralization reactions occur in a single mixing step and under substantially neutral or physiological pH conditions. These homogeneous nanostructured composite materials are useful for medical applications especially the regeneration of damaged bone in mammals. This invention is directed to the synthesis of peptide-amphiphiles with more than one amphiphilic moment and to supramolecular compositions comprised of such multi-dimensional peptide-amphiphiles. Supramolecular compositions can be formed by self assembly of multi-dimensional peptide-amphiphiles by mixing them with a solution comprising a monovalent cation.

  16. Fractionation and identification of antioxidant peptides from an enzymatically hydrolysed Palmaria palmata protein isolate.

    Science.gov (United States)

    Harnedy, Pádraigín A; O'Keeffe, Martina B; FitzGerald, Richard J

    2017-10-01

    Proteins derived from the macroalgal species Palmaria palmata have emerged as potential substrates for the generation of bioactive peptides. The aim of this study was to fractionate, identify and characterize antioxidant peptides from a P. palmata protein hydrolysate. The P. palmata protein hydrolysate generated with the food-grade proteolytic enzyme Corolase PP was sequentially fractionated using solid phase extraction and semi-preparative (SP) RP-HPLC. The most active SP-RP-HPLC peptide fraction (SP-RP-HPLC-30-F26) was analysed by ESI-MS/MS. Seventeen novel peptide sequences were identified in this fraction. Of the peptides selected for synthesis, Ser-Asp-Ile-Thr-Arg-Pro-Gly-Gly-Asn-Met, showed the highest oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) activity with values of 152.43±2.73 and 21.23±0.90nmolTE/μmol peptide, respectively. The results presented herein indicate that P. palmata derived peptides may have potential applications as health enhancing ingredients and as food preservatives due to their antioxidant activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Dynamic covalent chemistry enables formation of antimicrobial peptide quaternary assemblies in a completely abiotic manner

    Science.gov (United States)

    Reuther, James F.; Dees, Justine L.; Kolesnichenko, Igor V.; Hernandez, Erik T.; Ukraintsev, Dmitri V.; Guduru, Rusheel; Whiteley, Marvin; Anslyn, Eric V.

    2018-01-01

    Naturally occurring peptides and proteins often use dynamic disulfide bonds to impart defined tertiary/quaternary structures for the formation of binding pockets with uniform size and function. Although peptide synthesis and modification are well established, controlling quaternary structure formation remains a significant challenge. Here, we report the facile incorporation of aryl aldehyde and acyl hydrazide functionalities into peptide oligomers via solid-phase copper-catalysed azide-alkyne cycloaddition (SP-CuAAC) click reactions. When mixed, these complementary functional groups rapidly react in aqueous media at neutral pH to form peptide-peptide intermolecular macrocycles with highly tunable ring sizes. Moreover, sequence-specific figure-of-eight, dumbbell-shaped, zipper-like and multi-loop quaternary structures were formed selectively. Controlling the proportions of reacting peptides with mismatched numbers of complementary reactive groups results in the formation of higher-molecular-weight sequence-defined ladder polymers. This also amplified antimicrobial effectiveness in select cases. This strategy represents a general approach to the creation of complex abiotic peptide quaternary structures.

  18. An anti-infective synthetic peptide with dual antimicrobial and immunomodulatory activities.

    Science.gov (United States)

    Silva, O N; de la Fuente-Núñez, C; Haney, E F; Fensterseifer, I C M; Ribeiro, S M; Porto, W F; Brown, P; Faria-Junior, C; Rezende, T M B; Moreno, S E; Lu, T K; Hancock, R E W; Franco, O L

    2016-11-02

    Antibiotic-resistant infections are predicted to kill 10 million people per year by 2050, costing the global economy $100 trillion. Therefore, there is an urgent need to develop alternative technologies. We have engineered a synthetic peptide called clavanin-MO, derived from a marine tunicate antimicrobial peptide, which exhibits potent antimicrobial and immunomodulatory properties both in vitro and in vivo. The peptide effectively killed a panel of representative bacterial strains, including multidrug-resistant hospital isolates. Antimicrobial activity of the peptide was demonstrated in animal models, reducing bacterial counts by six orders of magnitude, and contributing to infection clearance. In addition, clavanin-MO was capable of modulating innate immunity by stimulating leukocyte recruitment to the site of infection, and production of immune mediators GM-CSF, IFN-γ and MCP-1, while suppressing an excessive and potentially harmful inflammatory response by increasing synthesis of anti-inflammatory cytokines such as IL-10 and repressing the levels of pro-inflammatory cytokines IL-12 and TNF-α. Finally, treatment with the peptide protected mice against otherwise lethal infections caused by both Gram-negative and -positive drug-resistant strains. The peptide presented here directly kills bacteria and further helps resolve infections through its immune modulatory properties. Peptide anti-infective therapeutics with combined antimicrobial and immunomodulatory properties represent a new approach to treat antibiotic-resistant infections.

  19. Antimicrobial activity of the indolicidin-derived novel synthetic peptide In-58.

    Science.gov (United States)

    Vasilchenko, A S; Vasilchenko, A V; Pashkova, T M; Smirnova, M P; Kolodkin, N I; Manukhov, I V; Zavilgelsky, G B; Sizova, E A; Kartashova, O L; Simbirtsev, A S; Rogozhin, E A; Duskaev, G K; Sycheva, M V

    2017-12-01

    Natural peptides with antimicrobial activity are extremely diverse, and peptide synthesis technologies make it possible to significantly improve their properties for specific tasks. Here, we investigate the biological properties of the natural peptide indolicidin and the indolicidin-derived novel synthetic peptide In-58. In-58 was generated by replacing all tryptophan residues on phenylalanine in D-configuration; the α-amino group in the main chain also was modified by unsaturated fatty acid. Compared with indolicidin, In-58 is more bactericidal, more resistant to proteinase K, and less toxic to mammalian cells. Using molecular physics approaches, we characterized the action of In-58 on bacterial cells at the cellular level. Also, we have found that studied peptides damage bacterial membranes. Using the Escherichia coli luminescent biosensor strain MG1655 (pcolD'::lux), we investigated the action of indolicidin and In-58 at the subcellular level. At subinhibitory concentrations, indolicidin and In-58 induced an SOS response. Our data suggest that indolicidin damages the DNA, but bacterial membrane perturbation is its principal mode of action. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

  20. Formation of ferric oxyhydroxide nanoparticles mediated by peptides in anchovy (Engraulis japonicus) muscle protein hydrolysate.

    Science.gov (United States)

    Wu, Haohao; Liu, Zunying; Dong, Shiyuan; Zhao, Yuanhui; Huang, Hai; Zeng, Mingyong

    2013-01-09

    Nanosized iron fortificants appear to be promising and can be synthesized in a greener way using peptides as biotemplates. Anchovy is a huge underdeveloped source of muscle protein that enhances human nonheme iron absorption. This paper shows that peptides in anchovy ( Engraulis japonicus ) muscle protein hydrolysate (AMPH) mediate the formation of monodispersed ferric oxyhydroxide nanoparticles (FeONPs) with diameters of 20-40 nm above pH 3.0. Peptides in AMPH nucleate iron through carboxyl groups and crystal growth then occur as a result of condensation of carboxylate-ligated hydroxide iron centers, yielding Fe-O-Fe cross-link bonds. Monomers of FeONPs are formed after steric obstruction of further crystal growth by peptide backbones with certain lengths and further stabilized by surface-adsorbed peptides. The iron-loading capacity of peptides in AMPH is up to 27.5 mg iron/g peptide. Overall, the present study provides a greener alternative route to the synthesis of FeONPs.

  1. Synthesis of Constrained Peptidomimetics via the Pictet-Spengler Reaction

    DEFF Research Database (Denmark)

    Petersen, Rico; Komnatnyy, Vitaly V.; Nielsen, Thomas E.

    2016-01-01

    Peptidomimetics offers a solution to the poor pharmacokinetic properties displayed by natural peptides, by providing pharmaceutically useful chemical structures with the ability to mimic the endogenous polyamide structure. This chapter gives an overview of the past decade’s developments in the fi......Peptidomimetics offers a solution to the poor pharmacokinetic properties displayed by natural peptides, by providing pharmaceutically useful chemical structures with the ability to mimic the endogenous polyamide structure. This chapter gives an overview of the past decade’s developments...... in the field of Pictet-Spengler reactions for the synthesis of peptidomimetics, with an emphasis on the applications of constrained heterocycles in mimicry of peptide geometry and biology....

  2. Arrangement of Proteinogenic α-Amino Acids on a Cyclic Peptide Comprising Alternate Biphenyl-Cored ζ-Amino Acids.

    Science.gov (United States)

    Tashiro, Shohei; Chiba, Masayuki; Shionoya, Mitsuhiko

    2017-05-18

    Aiming at precisely arranging several proteinogenic α-amino acids on a folded scaffold, we have developed a cyclic hexapeptide comprising an alternate sequence of biphenyl-cored ζ-amino acids and proteinogenic α-amino acids such as l-leucine. The amino acids were connected by typical peptide synthesis, and the resultant linear hexapeptide was intramolecularly cyclized to form a target cyclic peptide. Theoretical analyses and NMR spectroscopy suggested that the cyclic peptide was folded into an unsymmetrical conformation, and the structure was likely to be flexible in CHCl 3 . The optical properties including UV/Vis absorption, fluorescence, and circular dichroism (CD) were also evaluated. Furthermore, the cyclic peptide became soluble in water by introducing three carboxylate groups at the periphery of the cyclic skeleton. This α/ζ-alternating cyclic peptide is therefore expected to serve as a unique scaffold for arranging several functionalities. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Construction and screening of vast libraries of natural product-like macrocyclic peptides using in vitro display technologies.

    Science.gov (United States)

    Bashiruddin, Nasir K; Suga, Hiroaki

    2015-02-01

    Macrocyclic structure and backbone N-methylation represent characteristic features of peptidic natural products, which play critical roles in their biological activity. Although natural products have been the traditional source of such peptides, recent developments in synthesizing natural product-like macrocyclic peptides using reconstituted translation systems have enabled us to construct vast trillion-member libraries of non-standard macrocyclic peptides. In addition, a method for displaying such libraries on their corresponding mRNA templates allows us to rapidly screen them for potent ligands against various drug targets. This review describes methodologies for the ribosomal synthesis of novel natural product-like macrocyclic peptides and their recent applications in the discovery of bioactive molecules using in vitro display technologies. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Development of a bioactive fiber with immobilized synthetic peptides designed from the active site of a beetle defensin.

    Science.gov (United States)

    Nakamura, Makoto; Iwasaki, Takashi; Tokino, Seiji; Asaoka, Ai; Yamakawa, Minoru; Ishibashi, Jun

    2011-05-09

    The 9-mer peptides RLYLRIGRR and RLLLRIGRR were immobilized to amino-functionalized cotton fibers by a modification of the SPOT synthesis technique. The antibacterial activities of the peptide-immobilized cotton fibers against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) were investigated. Antibacterial assays revealed that these fibers inhibit the growth of MRSA and the antibacterial activities were maintained after washing and sterilization by autoclaving. The anticancer effect of the peptide-immobilized fiber was also investigated with mouse myeloma cells and human leukemia cells. These results indicate that these fibers have strong growth inhibition activity against bacteria and cancer cells.

  5. "Clicked" sugar-curcumin conjugate: modulator of amyloid-β and tau peptide aggregation at ultralow concentrations.

    Science.gov (United States)

    Dolai, Sukanta; Shi, Wei; Corbo, Christopher; Sun, Chong; Averick, Saadyah; Obeysekera, Dinali; Farid, Mina; Alonso, Alejandra; Banerjee, Probal; Raja, Krishnaswami

    2011-12-21

    The synthesis of a water/plasma soluble, noncytotoxic, "clicked" sugar-derivative of curcumin with amplified bioefficacy in modulating amyloid-β and tau peptide aggregation is presented. Curcumin inhibits amyloid-β and tau peptide aggregation at micromolar concentrations; the sugar-curcumin conjugate inhibits Aβ and tau peptide aggregation at concentrations as low as 8 nM and 0.1 nM, respectively. In comparison to curcumin, this conveniently synthesized Alzheimer's drug candidate is a more powerful antioxidant.

  6. Development of peptide-functionalized synthetic hydrogel microarrays for stem cell and tissue engineering applications.

    Science.gov (United States)

    Jia, Jia; Coyle, Robert C; Richards, Dylan J; Berry, Christopher Lloyd; Barrs, Ryan Walker; Biggs, Joshua; James Chou, C; Trusk, Thomas C; Mei, Ying

    2016-11-01

    Synthetic polymer microarray technology holds remarkable promise to rapidly identify suitable biomaterials for stem cell and tissue engineering applications. However, most of previous microarrayed synthetic polymers do not possess biological ligands (e.g., peptides) to directly engage cell surface receptors. Here, we report the development of peptide-functionalized hydrogel microarrays based on light-assisted copolymerization of poly(ethylene glycol) diacrylates (PEGDA) and methacrylated-peptides. Using solid-phase peptide/organic synthesis, we developed an efficient route to synthesize methacrylated-peptides. In parallel, we identified PEG hydrogels that effectively inhibit non-specific cell adhesion by using PEGDA-700 (M. W.=700) as a monomer. The combined use of these chemistries enables the development of a powerful platform to prepare peptide-functionalized PEG hydrogel microarrays. Additionally, we identified a linker composed of 4 glycines to ensure sufficient exposure of the peptide moieties from hydrogel surfaces. Further, we used this system to directly compare cell adhesion abilities of several related RGD peptides: RGD, RGDS, RGDSG and RGDSP. Finally, we combined the peptide-functionalized hydrogel technology with bioinformatics to construct a library composed of 12 different RGD peptides, including 6 unexplored RGD peptides, to develop culture substrates for hiPSC-derived cardiomyocytes (hiPSC-CMs), a cell type known for poor adhesion to synthetic substrates. 2 out of 6 unexplored RGD peptides showed substantial activities to support hiPSC-CMs. Among them, PMQKMRGDVFSP from laminin β4 subunit was found to support the highest adhesion and sarcomere formation of hiPSC-CMs. With bioinformatics, the peptide-functionalized hydrogel microarrays accelerate the discovery of novel biological ligands to develop biomaterials for stem cell and tissue engineering applications. In this manuscript, we described the development of a robust approach to prepare peptide

  7. Chemistry of aqueous silica nanoparticle surfaces and the mechanism of selective peptide adsorption.

    Science.gov (United States)

    Patwardhan, Siddharth V; Emami, Fateme S; Berry, Rajiv J; Jones, Sharon E; Naik, Rajesh R; Deschaume, Olivier; Heinz, Hendrik; Perry, Carole C

    2012-04-11

    Control over selective recognition of biomolecules on inorganic nanoparticles is a major challenge for the synthesis of new catalysts, functional carriers for therapeutics, and assembly of renewable biobased materials. We found low sequence similarity among sequences of peptides strongly attracted to amorphous silica nanoparticles of various size (15-450 nm) using combinatorial phage display methods. Characterization of the surface by acid base titrations and zeta potential measurements revealed that the acidity of the silica particles increased with larger particle size, corresponding to between 5% and 20% ionization of silanol groups at pH 7. The wide range of surface ionization results in the attraction of increasingly basic peptides to increasingly acidic nanoparticles, along with major changes in the aqueous interfacial layer as seen in molecular dynamics simulation. We identified the mechanism of peptide adsorption using binding assays, zeta potential measurements, IR spectra, and molecular simulations of the purified peptides (without phage) in contact with uniformly sized silica particles. Positively charged peptides are strongly attracted to anionic silica surfaces by ion pairing of protonated N-termini, Lys side chains, and Arg side chains with negatively charged siloxide groups. Further, attraction of the peptides to the surface involves hydrogen bonds between polar groups in the peptide with silanol and siloxide groups on the silica surface, as well as ion-dipole, dipole-dipole, and van-der-Waals interactions. Electrostatic attraction between peptides and particle surfaces is supported by neutralization of zeta potentials, an inverse correlation between the required peptide concentration for measurable adsorption and the peptide pI, and proximity of cationic groups to the surface in the computation. The importance of hydrogen bonds and polar interactions is supported by adsorption of noncationic peptides containing Ser, His, and Asp residues, including

  8. Organic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S.E.

    1991-01-01

    This paper reports on reactions of organoboranes. Organoboron routes to unsaturated hydrocarbons. Boronic ester homologation. Properties of organosilicon compounds. Alkene synthesis (Peterson olefination). Allylsilanes and acylsilanes.

  9. Modern extensions of native chemical ligation for chemical protein synthesis.

    Science.gov (United States)

    Malins, Lara R; Payne, Richard J

    2015-01-01

    Over the past 20 years, native chemical ligation has facilitated the synthesis of numerous complex peptide and protein targets, with and without post-translational modifications, as well as the design and construction of a variety of engineered protein variants. This powerful methodology has also served as a platform for the development of related chemoselective ligation technologies which have greatly expanded the scope and flexibility of ligation chemistry. This chapter details a number of important extensions of the original native chemical ligation manifold, with particular focus on the application of new methods in the total chemical synthesis of proteins. Topics covered include the development of auxiliary-based ligation methods, the post-ligation manipulation of Cys residues, and the synthesis and utility of unnatural amino acid building blocks (bearing reactive thiol or selenol functionalities) in chemoselective ligation chemistry. Contemporary applications of these techniques to the total chemical synthesis of peptides and proteins are described.

  10. Peptide Level Turnover Measurements Enable the Study of Proteoform Dynamics.

    Science.gov (United States)

    Zecha, Jana; Meng, Chen; Zolg, Daniel Paul; Samaras, Patroklos; Wilhelm, Mathias; Kuster, Bernhard

    2018-05-01

    The coordination of protein synthesis and degradation regulating protein abundance is a fundamental process in cellular homeostasis. Today, mass spectrometry-based technologies allow determination of endogenous protein turnover on a proteome-wide scale. However, standard dynamic SILAC (Stable Isotope Labeling in Cell Culture) approaches can suffer from missing data across pulse time-points limiting the accuracy of such analysis. This issue is of particular relevance when studying protein stability at the level of proteoforms because often only single peptides distinguish between different protein products of the same gene. To address this shortcoming, we evaluated the merits of combining dynamic SILAC and tandem mass tag (TMT)-labeling of ten pulse time-points in a single experiment. Although the comparison to the standard dynamic SILAC method showed a high concordance of protein turnover rates, the pulsed SILAC-TMT approach yielded more comprehensive data (6000 proteins on average) without missing values. Replicate analysis further established that the same reproducibility of turnover rate determination can be obtained for peptides and proteins facilitating proteoform resolved investigation of protein stability. We provide several examples of differentially turned over splice variants and show that post-translational modifications can affect cellular protein half-lives. For example, N-terminally processed peptides exhibited both faster and slower turnover behavior compared with other peptides of the same protein. In addition, the suspected proteolytic processing of the fusion protein FAU was substantiated by measuring vastly different stabilities of the cleavage products. Furthermore, differential peptide turnover suggested a previously unknown mechanism of activity regulation by post-translational destabilization of cathepsin D as well as the DNA helicase BLM. Finally, our comprehensive data set facilitated a detailed evaluation of the impact of protein

  11. Selecting optimal conditions for Alcalase CLEA-OM for synthesis of dipeptides in organic media

    NARCIS (Netherlands)

    Vossenberg, P.; Beeftink, H.H.; Nuijens, T.; Cohen Stuart, M.A.; Tramper, J.

    2012-01-01

    In protease-catalyzed peptide synthesis, the availability of water is essential, as a compromise must be made between on the one hand the overall enzymatic activity and, on the other hand, the rate of product synthesis. Water is essential for enzyme activity, but at the same time causes hydrolytic

  12. The Synthesis of cis- and trans-Fused Bicyclic Sugar Amino Acids

    NARCIS (Netherlands)

    Risseeuw, Martijn D.P.; Grotenbreg, Gijsbert M.; Witte, Martin D.; Tuin, Adriaan W.; Leeuwenburgh, Michiel A.; Marel, Gijsbert A. van der; Overkleeft, Herman S.; Overhand, Mark

    2006-01-01

    Four isomeric bicyclic sugar amino acids (SAAs) were prepared from an α-acetylenic-C-glucoside by employing a Petasis olefination and a ring-closing metathesis (RCM) as key steps. The applicability of the resulting SAAs in solid-phase peptide synthesis was demonstrated by the synthesis of a

  13. 'Dialyzable' Carbosilane Dendrimers as Soluble Supports in Organic Synthesis: Proof of principle, application and diafiltration performance

    NARCIS (Netherlands)

    Wander, M.

    2012-01-01

    Since the development of polystyrene as (insoluble) support for the synthesis of peptides by Merrifield in the 1960s, the application of supported synthesis in both industrial and academic research has increased. The introduction of dendrimers as supports solved many of the problems arising from the

  14. Peptides and Food Intake

    Directory of Open Access Journals (Sweden)

    Carmen Sobrino Crespo

    2014-04-01

    Full Text Available Nutrients created by the digestion of food are proposed to active G protein coupled receptors on the luminal side of enteroendocrine cells e.g. the L-cell. This stimulates the release of gut hormones. Hormones released from the gut and adipose tissue play an important rol in the regulation of food intake and energy expenditure (1.Many circulating signals, including gut hormones, can influence the activity of the arcuate nucleus (ARC neurons directly, after passing across the median eminence. The ARC is adjacent to the median eminence, a circumventricular organ with fenestrated capillaries and hence an incomplete blood-brain barrier (2. The ARC of the hypothalamus is believed to play a crucial role in the regulation of food intake and energy homeostasis. The ARC contains two populations of neurons with opposing effect on food intake (3. Medially located orexigenic neurons (i.e those stimulating appetite express neuropeptide Y (NPY and agouti-related protein (AgRP (4-5. Anorexigenic neurons (i.e. those inhibiting appetite in the lateral ARC express alpha-melanocyte stimulating hormone (α-MSH derived from pro-opiomelanocortin (POMC and cocaine and amphetamine-regulated transcript (CART (6. The balance between activities of these neuronal circuits is critical to body weight regulation.In contrast, other peripheral signals influence the hypothalamus indirectly via afferent neuronal pathway and brainstem circuits. In this context gastrointestinal’s vagal afferents are activated by mechanoreceptors and chemoreceptors, and converge in the nucleus of the tractus solitaries (NTS of the brainstem. Neuronal projections from the NTS, in turn, carry signals to the hypotalamus (1, 7. Gut hormones also alter the activity of the ascending vagal pathway from the gut to the brainstem. In the cases of ghrelin and Peptide tyrosine tyrosine (PYY, there are evidences for both to have a direct action on the arcuate nucleus and an action via the vagus nerve a

  15. Silicon-Containing Amino Acids: Synthetic Aspects, Conformational Studies, and Applications to Bioactive Peptides.

    Science.gov (United States)

    Rémond, Emmanuelle; Martin, Charlotte; Martinez, Jean; Cavelier, Florine

    2016-10-12

    Unnatural α-amino acids form a family of essential molecules used for, among other applications, the synthesis of modified peptides, to improve resistance to proteolytic enzyme degradation, and to modulate physico- and biochemical properties of bioactive peptides as well as chiral inducers in asymmetric synthesis. Among them, silicon-containing unnatural amino acids are becoming an interesting new class of building blocks. The replacement of carbon atoms in bioactive substances with silicon is becoming increasingly popular. Peptides containing silyl amino acids hold great promise for maintaining or reinforcing the biological activity of active compounds, while they simultaneously enhance their resistance to enzyme degradation. In addition, the lipophilicity of the silicon atom facilitates their membrane crossing and their bioavailability. Nowadays, the interest of the pharmaceutical industry in peptide- and protein-based therapies is increasing. In this respect, silicon-containing amino acids and peptides are likely to be a significant part of future innovations in this area, and more generally in the area of biomolecules. In this process, commercial availability of silicon-containing amino acids is necessary: new syntheses have been developed, and work in this area is ongoing. This review aims to be a comprehensive and general summary of the different methods used to prepare silicon-containing amino acids and their implications on conformational structures and biological applications when they are incorporated into bioactive molecules.

  16. Radioiodination of vasoactive intestinal peptide (VIP)

    International Nuclear Information System (INIS)

    Wang, Y.; Wang, L.; Yin, D.

    2002-01-01

    . Human IgG was radiolabelled by direct (iodogen) and indirect method (ATE precursor), 96% and 77% of labelling efficiency were obtained, respectively. Optimization of labelling conditions and biological activity was studied. More than 76% of 125 I-IgG kept active. The emphasis focused on the radiolabelling of VIP. The optimization of labelling conditions, various kinds of analysing and isolation methods, stability and biological activity were investigated in our Lab. The results showed that iodogen oxidant worked well with 69% of labelling efficiency. S 125 IB could be conjugated with VIP easily, yielding 75%. HPLC was an effective method to separate radiolabelled VIP from other compounds. 125 IBA-VIP showed better in vitro stability than 125 I-VIP. The primary studies showed no significant difference in biological activity. We can conclude that iodogen was an efficient oxidant for I - to I + or I 2 , which can react with ATE, IgG and VIP. As a prosthetic group, ATE could connect radioactive iodine and proteins or peptides and worked well. So the conjugation of S 125 IB and IgG or VIP was easy to perform. The biological activity of products in direct and indirect labelling was nearly of the same. But the indirect product showed better stability than direct labelled product. The labelling of VIP with iodine-123 instead of iodine-125 should not affect the drawed conclusion. We will make further study to complete the synthesis of 123 I-VIP. (author)

  17. Chemoselective Synthesis of Carbamates using CO2 as Carbon Source.

    Science.gov (United States)

    Riemer, Daniel; Hirapara, Pradipbhai; Das, Shoubhik

    2016-08-09

    Synthesis of carbamates directly from amines using CO2 as the carbon source is a straightforward and sustainable approach. Herein, we describe a highly effective and chemoselective methodology for the synthesis of carbamates at room temperature and atmospheric pressure. This methodology can also be applied to protect the amino group in amino acids and peptides, and also to synthesize important pharmaceuticals. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Exploration of the Medicinal Peptide Space.

    Science.gov (United States)

    Gevaert, Bert; Stalmans, Sofie; Wynendaele, Evelien; Taevernier, Lien; Bracke, Nathalie; D'Hondt, Matthias; De Spiegeleer, Bart

    2016-01-01

    The chemical properties of peptide medicines, known as the 'medicinal peptide space' is considered a multi-dimensional subset of the global peptide space, where each dimension represents a chemical descriptor. These descriptors can be linked to biofunctional, medicinal properties to varying degrees. Knowledge of this space can increase the efficiency of the peptide-drug discovery and development process, as well as advance our understanding and classification of peptide medicines. For 245 peptide drugs, already available on the market or in clinical development, multivariate dataexploration was performed using peptide relevant physicochemical descriptors, their specific peptidedrug target and their clinical use. Our retrospective analysis indicates that clusters in the medicinal peptide space are located in a relatively narrow range of the physicochemical space: dense and empty regions were found, which can be explored for the discovery of novel peptide drugs.

  19. Cyclic peptide therapeutics: past, present and future.

    Science.gov (United States)

    Zorzi, Alessandro; Deyle, Kaycie; Heinis, Christian

    2017-06-01

    Cyclic peptides combine several favorable properties such as good binding affinity, target selectivity and low toxicity that make them an attractive modality for the development of therapeutics. Over 40 cyclic peptide drugs are currently in clinical use and around one new cyclic peptide drug enters the market every year on average. The vast majority of clinically approved cyclic peptides are derived from natural products, such as antimicrobials or human peptide hormones. New powerful techniques based on rational design and in vitro evolution have enabled the de novo development of cyclic peptide ligands to targets for which nature does not offer solutions. A look at the cyclic peptides currently under clinical evaluation shows that several have been developed using such techniques. This new source for cyclic peptide ligands introduces a freshness to the field, and it is likely that de novo developed cyclic peptides will be in clinical use in the near future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Perspectives and Peptides of the Next Generation

    Science.gov (United States)

    Brogden, Kim A.

    Shortly after their discovery, antimicrobial peptides from prokaryotes and eukaryotes were recognized as the next potential generation of pharmaceuticals to treat antibiotic-resistant bacterial infections and septic shock, to preserve food, or to sanitize surfaces. Initial research focused on identifying the spectrum of antimicrobial agents, determining the range of antimicrobial activities against bacterial, fungal, and viral pathogens, and assessing the antimicrobial activity of synthetic peptides versus their natural counterparts. Subsequent research then focused on the mechanisms of antimicrobial peptide activity in model membrane systems not only to identify the mechanisms of antimicrobial peptide activity in microorganisms but also to discern differences in cytotoxicity for prokaryotic and eukaryotic cells. Recent, contemporary work now focuses on current and future efforts to construct hybrid peptides, peptide congeners, stabilized peptides, peptide conjugates, and immobilized peptides for unique and specific applications to control the growth of microorganisms in vitro and in vivo.