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Sample records for tnfr-fc fusion protein

  1. LPS-induced suppression of gastric motility relieved by TNFR:Fc construct in dorsal vagal complex.

    Science.gov (United States)

    Hermann, Gerlinda E; Tovar, C Amy; Rogers, Richard C

    2002-09-01

    Our previous studies suggested that the cytokine tumor necrosis factor-alpha (TNF-alpha) may act within the neural circuitry of the medullary dorsal vagal complex (DVC) to affect changes in gastric function, such as gastric stasis, loss of appetite, nausea, and vomiting. The definitive demonstration that endogenously generated TNF-alpha is capable of affecting gastric function via the DVC circuitry has been impeded by the lack of an antagonist for TNF-alpha. The present studies used localized central nervous system applications of the TNF-adsorbant construct (TNFR:Fc; TNF-receptor linked to the Fc portion of the human immunoglobulin IgG1) to attempt to neutralize the suppressive effects of endogenously produced TNF-alpha. Gastric motility of thiobutabarbital-anesthetized rats was monitored after systemic administration of lipopolysaccharide (LPS) to induce TNF-alpha production. Continuous perfusion of the floor of the fourth ventricle with TNFR:Fc reversed the potent gastroinhibition induced by LPS, i.e., central thyrotropin-releasing hormone-induced increases in motility were not inhibited. This disinhibition of gastric stasis was not seen after intravenous administration of similar doses of TNFR:Fc nor ventricular application of the Fc fragment of human immunoglobulin. These results validate our previous studies that suggest that circulating TNF-alpha may act directly within the DVC to affect gastric function in a variety of pathophysiological states.

  2. Fusion-protein-assisted protein crystallization.

    Science.gov (United States)

    Kobe, Bostjan; Ve, Thomas; Williams, Simon J

    2015-07-01

    Fusion proteins can be used directly in protein crystallization to assist crystallization in at least two different ways. In one approach, the `heterologous fusion-protein approach', the fusion partner can provide additional surface area to promote crystal contact formation. In another approach, the `fusion of interacting proteins approach', protein assemblies can be stabilized by covalently linking the interacting partners. The linker connecting the proteins plays different roles in the two applications: in the first approach a rigid linker is required to reduce conformational heterogeneity; in the second, conversely, a flexible linker is required that allows the native interaction between the fused proteins. The two approaches can also be combined. The recent applications of fusion-protein technology in protein crystallization from the work of our own and other laboratories are briefly reviewed.

  3. Exo-endo cellulase fusion protein

    Science.gov (United States)

    Bower, Benjamin S [Palo Alto, CA; Larenas, Edmund A [Palo Alto, CA; Mitchinson, Colin [Palo Alto, CA

    2012-01-17

    The present invention relates to a heterologous exo-endo cellulase fusion construct, which encodes a fusion protein having cellulolytic activity comprising a catalytic domain derived from a fungal exo-cellobiohydrolase and a catalytic domain derived from an endoglucanase. The invention also relates to vectors and fungal host cells comprising the heterologous exo-endo cellulase fusion construct as well as methods for producing a cellulase fusion protein and enzymatic cellulase compositions.

  4. Clinical Significance of Myeloid-Related Protein 8/14 as a Predictor for Biological Treatment and Disease Activity in Rheumatoid Arthritis.

    Science.gov (United States)

    Yunchun, Li; Yue, Wang; Jun, Fang Zhong; Qizhu, Su; Liumei, Ding

    2018-01-01

    To investigate the serum level of Myeloid-Related Protein 8/14 complex (MRP8/14) and to predict and monitor the response to biologic treatment in rheumatoid arthritis (RA) patients. Each patient underwent clinical examination and blood sampling for assessment of serum high-sensitivity C-reactive protein (hs-CRP) levels, erythrocyte sedimentation rate (ESR), rheumatoid factors (RF), anti-cyclic citrullinated protein antibodies (anti-CCP), and serum concentrations of MRP8/14 protein complexes (myeloid-related proteins, MRP8/14) were measured at baseline, and weeks 4 and 12 (after initiation of treatment). Serum MRP8/14 protein complex levels correlated with DAS28 and anti-CCP antibody. MRP8/14 protein complex levels decreased significantly after 12 weeks treatment with biological therapy: mono-rhTNFR-Fc active group. rhTNFR-Fc plus methotrexate (MTX) decreased MRP8/14 protein complex levels from 11839±1849 ng/ml to 5423±1130 ng/ml ( p <0.01) a reduction of 54.2% compared with 32.9% in the rhTNFR-Fc group. MRP8/14 protein complex levels were increased in active stage RA patients. MRP8/14 levels were decreased with rhTNFR-Fc treatment, suggesting serum concentrations of MRP8/14 protein complex might be a promising biomarker to predict responses to biological therapy in active RA patients at baseline and could be used to monitor responses to treatment across different mechanisms of action. © 2018 by the Association of Clinical Scientists, Inc.

  5. Crystal structures of MBP fusion proteins.

    Science.gov (United States)

    Waugh, David S

    2016-03-01

    Although chaperone-assisted protein crystallization remains a comparatively rare undertaking, the number of crystal structures of polypeptides fused to maltose-binding protein (MBP) that have been deposited in the Protein Data Bank (PDB) has grown dramatically during the past decade. Altogether, 102 fusion protein structures were detected by Basic Local Alignment Search Tool (BLAST) analysis. Collectively, these structures comprise a range of sizes, space groups, and resolutions that are typical of the PDB as a whole. While most of these MBP fusion proteins were equipped with short inter-domain linkers to increase their rigidity, fusion proteins with long linkers have also been crystallized. In some cases, surface entropy reduction mutations in MBP appear to have facilitated the formation of crystals. A comparison of the structures of fused and unfused proteins, where both are available, reveals that MBP-mediated structural distortions are very rare. © 2016 The Protein Society.

  6. Hendra virus fusion protein transmembrane domain contributes to pre-fusion protein stability.

    Science.gov (United States)

    Webb, Stacy; Nagy, Tamas; Moseley, Hunter; Fried, Michael; Dutch, Rebecca

    2017-04-07

    Enveloped viruses utilize fusion (F) proteins studding the surface of the virus to facilitate membrane fusion with a target cell membrane. Fusion of the viral envelope with a cellular membrane is required for release of viral genomic material, so the virus can ultimately reproduce and spread. To drive fusion, the F protein undergoes an irreversible conformational change, transitioning from a metastable pre-fusion conformation to a more thermodynamically stable post-fusion structure. Understanding the elements that control stability of the pre-fusion state and triggering to the post-fusion conformation is important for understanding F protein function. Mutations in F protein transmembrane (TM) domains implicated the TM domain in the fusion process, but the structural and molecular details in fusion remain unclear. Previously, analytical ultracentrifugation was utilized to demonstrate that isolated TM domains of Hendra virus F protein associate in a monomer-trimer equilibrium (Smith, E. C., Smith, S. E., Carter, J. R., Webb, S. R., Gibson, K. M., Hellman, L. M., Fried, M. G., and Dutch, R. E. (2013) J. Biol. Chem. 288, 35726-35735). To determine factors driving this association, 140 paramyxovirus F protein TM domain sequences were analyzed. A heptad repeat of β-branched residues was found, and analysis of the Hendra virus F TM domain revealed a heptad repeat leucine-isoleucine zipper motif (LIZ). Replacement of the LIZ with alanine resulted in dramatically reduced TM-TM association. Mutation of the LIZ in the whole protein resulted in decreased protein stability, including pre-fusion conformation stability. Together, our data suggest that the heptad repeat LIZ contributed to TM-TM association and is important for F protein function and pre-fusion stability. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Mutations in the fusion peptide and heptad repeat regions of the Newcastle disease virus fusion protein block fusion.

    OpenAIRE

    Sergel-Germano, T; McQuain, C; Morrison, T

    1994-01-01

    Nonconservative mutations were introduced by site-specific mutagenesis into the fusion peptide and the adjacent heptad repeat region of the fusion protein of Newcastle disease virus in order to determine the role of both regions in the fusion activity of the protein. Mutations in both regions that allowed for proper folding and intracellular transport of the protein blocked the fusion activity of the protein when assayed in the presence of the hemagglutinin-neuraminidase protein.

  8. Mitochondrial Fusion Proteins and Human Diseases

    Directory of Open Access Journals (Sweden)

    Michela Ranieri

    2013-01-01

    Full Text Available Mitochondria are highly dynamic, complex organelles that continuously alter their shape, ranging between two opposite processes, fission and fusion, in response to several stimuli and the metabolic demands of the cell. Alterations in mitochondrial dynamics due to mutations in proteins involved in the fusion-fission machinery represent an important pathogenic mechanism of human diseases. The most relevant proteins involved in the mitochondrial fusion process are three GTPase dynamin-like proteins: mitofusin 1 (MFN1 and 2 (MFN2, located in the outer mitochondrial membrane, and optic atrophy protein 1 (OPA1, in the inner membrane. An expanding number of degenerative disorders are associated with mutations in the genes encoding MFN2 and OPA1, including Charcot-Marie-Tooth disease type 2A and autosomal dominant optic atrophy. While these disorders can still be considered rare, defective mitochondrial dynamics seem to play a significant role in the molecular and cellular pathogenesis of more common neurodegenerative diseases, for example, Alzheimer’s and Parkinson’s diseases. This review provides an overview of the basic molecular mechanisms involved in mitochondrial fusion and focuses on the alteration in mitochondrial DNA amount resulting from impairment of mitochondrial dynamics. We also review the literature describing the main disorders associated with the disruption of mitochondrial fusion.

  9. Fusion proteins useful for producing pinene

    Science.gov (United States)

    Peralta-Yahya, Pamela P.; Keasling, Jay D

    2016-06-28

    The present invention provides for a modified host cell comprising a heterologous pinene synthase (PS), or enzymatically active fragment or variant thereof, and optionally a geranyl pyrophosphate synthase (GPPS), or enzymatically active fragment or variant thereof, or a fusion protein comprising: (a) a PS and (b) a GPPS linked by a linker.

  10. Fc-fusion Proteins in Therapy: An Updated View.

    Science.gov (United States)

    Jafari, Reza; Zolbanin, Naime M; Rafatpanah, Houshang; Majidi, Jafar; Kazemi, Tohid

    2017-01-01

    Fc-fusion proteins are composed of Fc region of IgG antibody (Hinge-CH2-CH3) and a desired linked protein. Fc region of Fc-fusion proteins can bind to neonatal Fc receptor (FcRn) thereby rescuing it from degradation. The first therapeutic Fc-fusion protein was introduced for the treatment of AIDS. The molecular designing is the first stage in production of Fc-fusion proteins. The amino acid residues in the Fc region and linked protein are very important in the bioactivity and affinity of the fusion proteins. Although, therapeutic monoclonal antibodies are the top selling biologics but the application of therapeutic Fc-fusion proteins in clinic is in progress and among these medications Etanercept is the most effective in therapy. At present, eleven Fc-fusion proteins have been approved by FDA. There are novel Fc-fusion proteins which are in pre-clinical and clinical development. In this article, we review the molecular and biological characteristics of Fc-fusion proteins and then further discuss the features of novel therapeutic Fc-fusion proteins. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Peptides and membrane fusion : Towards an understanding of the molecular mechanism of protein-induced fusion

    NARCIS (Netherlands)

    Pecheur, EI; Sainte-Marie, J; Bienvenue, A; Hoekstra, D

    1999-01-01

    Processes such as endo- or exocytosis, membrane recycling, fertilization and enveloped viruses infection require one or more critical membrane fusion reactions. A key feature in viral and cellular fusion phenomena is the involvement of specific fusion proteins. Among the few well-characterized

  12. MEMBRANE-FUSION OF SEMLIKI FOREST VIRUS INVOLVES HOMOTRIMERS OF THE FUSION PROTEIN

    NARCIS (Netherlands)

    WAHLBERG, JM; WILSCHUT, J; GAROFF, H

    1992-01-01

    Infection of cells with enveloped viruses is accomplished through membrane fusion. The binding and fusion Processes are mediated by the spike proteins in the envelope of the virus particle and usually involve a series of conformational changes in these proteins. We have studied the low-pH-mediated

  13. Structural characterization of Mumps virus fusion protein core

    International Nuclear Information System (INIS)

    Liu Yueyong; Xu Yanhui; Lou Zhiyong; Zhu Jieqing; Hu Xuebo; Gao, George F.; Qiu Bingsheng; Rao Zihe; Tien, Po

    2006-01-01

    The fusion proteins of enveloped viruses mediating the fusion between the viral and cellular membranes comprise two discontinuous heptad repeat (HR) domains located at the ectodomain of the enveloped glycoproteins. The crystal structure of the fusion protein core of Mumps virus (MuV) was determined at 2.2 A resolution. The complex is a six-helix bundle in which three HR1 peptides form a central highly hydrophobic coiled-coil and three HR2 peptides pack against the hydrophobic grooves on the surface of central coiled-coil in an oblique antiparallel manner. Fusion core of MuV, like those of simian virus 5 and human respiratory syncytium virus, forms typical 3-4-4-4-3 spacing. The similar charecterization in HR1 regions, as well as the existence of O-X-O motif in extended regions of HR2 helix, suggests a basic rule for the formation of the fusion core of viral fusion proteins

  14. Distinct roles for key karyogamy proteins during yeast nuclear fusion.

    Science.gov (United States)

    Melloy, Patricia; Shen, Shu; White, Erin; Rose, Mark D

    2009-09-01

    During yeast mating, cell fusion is followed by the congression and fusion of the two nuclei. Proteins required for nuclear fusion are found at the surface (Prm3p) and within the lumen (Kar2p, Kar5p, and Kar8p) of the nuclear envelope (NE). Electron tomography (ET) of zygotes revealed that mutations in these proteins block nuclear fusion with different morphologies, suggesting that they act in different steps of fusion. Specifically, prm3 zygotes were blocked before formation of membrane bridges, whereas kar2, kar5, and kar8 zygotes frequently contained them. Membrane bridges were significantly larger and occurred more frequently in kar2 and kar8, than in kar5 mutant zygotes. The kinetics of NE fusion in prm3, kar5, and kar8 mutants, measured by live-cell fluorescence microscopy, were well correlated with the size and frequency of bridges observed by ET. However the kar2 mutant was defective for transfer of NE lumenal GFP, but not diffusion within the lumen, suggesting that transfer was blocked at the NE fusion junction. These observations suggest that Prm3p acts before initiation of outer NE fusion, Kar5p may help dilation of the initial fusion pore, and Kar2p and Kar8p act after outer NE fusion, during inner NE fusion.

  15. Fusion proteins as alternate crystallization paths to difficult structure problems

    Science.gov (United States)

    Carter, Daniel C.; Rueker, Florian; Ho, Joseph X.; Lim, Kap; Keeling, Kim; Gilliland, Gary; Ji, Xinhua

    1994-01-01

    The three-dimensional structure of a peptide fusion product with glutathione transferase from Schistosoma japonicum (SjGST) has been solved by crystallographic methods to 2.5 A resolution. Peptides or proteins can be fused to SjGST and expressed in a plasmid for rapid synthesis in Escherichia coli. Fusion proteins created by this commercial method can be purified rapidly by chromatography on immobilized glutathione. The potential utility of using SjGST fusion proteins as alternate paths to the crystallization and structure determination of proteins is demonstrated.

  16. Positional effects of fusion partners on the yield and solubility of MBP fusion proteins.

    Science.gov (United States)

    Raran-Kurussi, Sreejith; Keefe, Karina; Waugh, David S

    2015-06-01

    Escherichia coli maltose-binding protein (MBP) is exceptionally effective at promoting the solubility of its fusion partners. However, there are conflicting reports in the literature claiming that (1) MBP is an effective solubility enhancer only when it is joined to the N-terminus of an aggregation-prone passenger protein, and (2) MBP is equally effective when fused to either end of the passenger. Here, we endeavor to resolve this controversy by comparing the solubility of a diverse set of MBP fusion proteins that, unlike those analyzed in previous studies, are identical in every way except for the order of the two domains. The results indicate that fusion proteins with an N-terminal MBP provide an excellent solubility advantage along with more robust expression when compared to analogous fusions in which MBP is the C-terminal fusion partner. We find that only intrinsically soluble passenger proteins (i.e., those not requiring a solubility enhancer) are produced as soluble fusions when they precede MBP. We also report that even subtle differences in inter-domain linker sequences can influence the solubility of fusion proteins. Published by Elsevier Inc.

  17. C-terminal tyrosine residues modulate the fusion activity of the Hendra virus fusion protein.

    Science.gov (United States)

    Popa, Andreea; Pager, Cara Teresia; Dutch, Rebecca Ellis

    2011-02-15

    The paramyxovirus family includes important human pathogens such as measles, mumps, respiratory syncytial virus, and the recently emerged, highly pathogenic Hendra and Nipah viruses. The viral fusion (F) protein plays critical roles in infection, promoting both the virus-cell membrane fusion events needed for viral entry as well as cell-cell fusion events leading to syncytia formation. We describe the surprising finding that addition of the short epitope HA tag to the cytoplasmic tail (CT) of the Hendra virus F protein leads to a significant increase in the extent of cell-cell membrane fusion. This increase was not due to alterations in surface expression, cleavage state, or association with lipid microdomains. Addition of a Myc tag of similar length did not alter Hendra F protein fusion activity, indicating that the observed stimulation was not solely a result of lengthening the CT. Three tyrosine residues within the HA tag were critical for the increase in the extent of fusion, suggesting C-terminal tyrosines may modulate Hendra fusion activity. The effects of addition of the HA tag varied with other fusion proteins, as parainfluenza virus 5 F-HA showed a decreased level of surface expression and no stimulation of fusion. These results indicate that additions to the C-terminal end of the F protein CT can modulate protein function in a sequence specific manner, reinforcing the need for careful analysis of epitope-tagged glycoproteins. In addition, our results implicate C-terminal tyrosine residues in the modulation of the membrane fusion reaction promoted by these viral glycoproteins.

  18. Rho GTPase activity modulates paramyxovirus fusion protein-mediated cell-cell fusion

    International Nuclear Information System (INIS)

    Schowalter, Rachel M.; Wurth, Mark A.; Aguilar, Hector C.; Lee, Benhur; Moncman, Carole L.; McCann, Richard O.; Dutch, Rebecca Ellis

    2006-01-01

    The paramyxovirus fusion protein (F) promotes fusion of the viral envelope with the plasma membrane of target cells as well as cell-cell fusion. The plasma membrane is closely associated with the actin cytoskeleton, but the role of actin dynamics in paramyxovirus F-mediated membrane fusion is unclear. We examined cell-cell fusion promoted by two different paramyxovirus F proteins in three cell types in the presence of constitutively active Rho family GTPases, major cellular coordinators of actin dynamics. Reporter gene and syncytia assays demonstrated that expression of either Rac1 V12 or Cdc42 V12 could increase cell-cell fusion promoted by the Hendra or SV5 glycoproteins, though the effect was dependent on the cell type expressing the viral glycoproteins. In contrast, RhoA L63 decreased cell-cell fusion promoted by Hendra glycoproteins but had little affect on SV5 F-mediated fusion. Also, data suggested that GTPase activation in the viral glycoprotein-containing cell was primarily responsible for changes in fusion. Additionally, we found that activated Cdc42 promoted nuclear rearrangement in syncytia

  19. The dengue virus type 2 envelope protein fusion peptide is essential for membrane fusion

    International Nuclear Information System (INIS)

    Huang, Claire Y.-H.; Butrapet, Siritorn; Moss, Kelly J.; Childers, Thomas; Erb, Steven M.; Calvert, Amanda E.; Silengo, Shawn J.; Kinney, Richard M.; Blair, Carol D.; Roehrig, John T.

    2010-01-01

    The flaviviral envelope (E) protein directs virus-mediated membrane fusion. To investigate membrane fusion as a requirement for virus growth, we introduced 27 unique mutations into the fusion peptide of an infectious cDNA clone of dengue 2 virus and recovered seven stable mutant viruses. The fusion efficiency of the mutants was impaired, demonstrating for the first time the requirement for specific FP AAs in optimal fusion. Mutant viruses exhibited different growth kinetics and/or genetic stabilities in different cell types and adult mosquitoes. Virus particles could be recovered following RNA transfection of cells with four lethal mutants; however, recovered viruses could not re-infect cells. These viruses could enter cells, but internalized virus appeared to be retained in endosomal compartments of infected cells, thus suggesting a fusion blockade. Mutations of the FP also resulted in reduced virus reactivity with flavivirus group-reactive antibodies, confirming earlier reports using virus-like particles.

  20. Functional analysis of the putative fusion domain of the Baculovirus envelope fusion protein F

    NARCIS (Netherlands)

    Westenberg, M.; Veenman, F.; Roode, E.C.; Goldbach, R.W.; Vlak, J.M.

    2004-01-01

    Group II nucleopolyhedroviruses (NPVs), e.g., Spodoptera exigua MNPV, lack a GP64-like protein that is present in group I NPVs but have an unrelated envelope fusion protein named F. In contrast to GP64, the F protein has to be activated by a posttranslational cleavage mechanism to become fusogenic.

  1. Antibody-IL2 Fusion Protein Delivery by Gene Transfer

    National Research Council Canada - National Science Library

    Gan, Jacek

    1998-01-01

    .... The KS-IL2 fusion protein recognizes the KSA antigen expressed on a broad range of human carcinomas, including breast cancer and is effective at preventing outgrowth of the KSA positive, syngeneic...

  2. Antibody-IL2 Fusion Protein Delivery by Gene Transfer

    National Research Council Canada - National Science Library

    Nicolet, Charles

    1997-01-01

    The purpose of the work described is to assess the feasibility of a gene therapy approach to deliver a specific antibody cytokine fusion protein called CC49-1L2 to a tumor expressing antigen reactive with the antibody...

  3. Breast Cancer Therapy Using Antibody-Endostatin Fusion Proteins

    National Research Council Canada - National Science Library

    Shin, Seung-Uon

    2006-01-01

    To produce a more effective form of Herceptin and improve efficacy of human endostatin, we have constructed an anti-HER2 IgG3-human endostatin fusion protein by joining human endostatin to the 3 end...

  4. Generation of Fluorescent Protein Fusions in Candida Species.

    Science.gov (United States)

    Gonia, Sara; Berman, Judith; Gale, Cheryl A

    2017-03-04

    Candida species, prevalent colonizers of the intestinal and genitourinary tracts, are the cause of the majority of invasive fungal infections in humans. Thus, molecular and genetic tools are needed to facilitate the study of their pathogenesis mechanisms. PCR-mediated gene modification is a straightforward and quick approach to generate epitope-tagged proteins to facilitate their detection. In particular, fluorescent protein (FP) fusions are powerful tools that allow visualization and quantitation of both yeast cells and proteins by fluorescence microscopy and immunoblotting, respectively. Plasmids containing FP encoding sequences, along with nutritional marker genes that facilitate the transformation of Candida species, have been generated for the purpose of FP construction and expression in Candida. Herein, we present a strategy for constructing a FP fusion in a Candida species. Plasmids containing the nourseothricin resistance transformation marker gene (NAT1) along with sequences for either green, yellow, or cherry FPs (GFP, YFP, mCherry) are used along with primers that include gene-specific sequences in a polymerase chain reaction (PCR) to generate a FP cassette. This gene-specific cassette has the ability to integrate into the 3'-end of the corresponding gene locus via homologous recombination. Successful in-frame fusion of the FP sequence into the gene locus of interest is verified genetically, followed by analysis of fusion protein expression by microscopy and/or immuno-detection methods. In addition, for the case of highly expressed proteins, successful fusions can be screened for primarily by fluorescence imaging techniques.

  5. A systematic investigation of the stability of green fluorescent protein fusion proteins.

    Science.gov (United States)

    Janczak, Monika; Bukowski, Michał; Górecki, Andrzej; Dubin, Grzegorz; Dubin, Adam; Wladyka, Benedykt

    2015-01-01

    X-ray crystallography provides important insights into structure-function relationship in biomolecules. However, protein crystals are usually hard to obtain which hinders our understanding of multiple important processes. Crystallization requires large amount of protein sample, whereas recombinant proteins are often unstable or insoluble. Green fluorescent protein (GFP) fusion is one of the approaches to increase protein synthesis, solubility and stability, facilitating crystallization. In this study we analyze the influence of the linker length, composition and the position of GFP relative to the fusion partner on the fusion protein production and stability. To this end, multiple constructs of enzymatically impaired variant of PemKSa toxin from Staphylococcus aureus CH91 fused to GFP were generated. Fusion protein production in Escherichia coli was evaluated. The proteins were purified and their stability tested. PemKSa-α14aa-GFP fusion provided best production and stability. Obtained results demonstrate the importance of optimization of fusion protein construct, including linker selection and the order of fusion partners, in obtaining high quantities of stable protein for crystallization.

  6. Delivery of therapeutic proteins as secretable TAT fusion products.

    Science.gov (United States)

    Flinterman, Marcella; Farzaneh, Farzin; Habib, Nagy; Malik, Farooq; Gäken, Joop; Tavassoli, Mahvash

    2009-02-01

    The trans-acting activator of transcription (TAT) protein transduction domain (PTD) mediates the transduction of peptides and proteins into target cells. The TAT-PTD has an important potential as a tool for the delivery of therapeutic agents. The production of TAT fusion proteins in bacteria, however, is problematic because of protein insolubility and the absence of eukaryotic post-translational modification. An attractive alternative, both for in vitro protein production and for in vivo applications, is the use of higher eukaryotic cells for secretion of TAT fusion proteins. However, the ubiquitous expression of furin endoprotease (PACE or SPC1) in the Golgi/endoplasmic reticulum, and the presence of furin recognition sequences within TAT-PTD, results in the cleavage and loss of the TAT-PTD domain during its secretory transition through the endoplasmic reticulum and Golgi. In this study, we show the development of a synthetic TATkappa-PTD in which mutation of the furin recognition sequences, but retention of protein transduction activity, allows secretion of recombinant proteins, followed by successful uptake of the modified protein, by the target cells. This system was used to successfully secrete marker protein, green fluorescent protein (GFP), and apoptin, a protein with tumor-specific cytotoxicity. Detection of GFP, phosphorylation, and induction of cell death by TATkappa-GFP-apoptin indicated that the secreted proteins were functional in target cells. This novel strategy therefore has important potential for the efficient delivery of therapeutic proteins.

  7. Protein aggregation kinetics during Protein A chromatography. Case study for an Fc fusion protein.

    Science.gov (United States)

    Shukla, Abhinav A; Gupta, Priyanka; Han, Xuejun

    2007-11-09

    Protein A chromatography has come to be widely adopted for large-scale purification of monoclonal antibodies and Fc fusion proteins. The low pH conditions required for Protein A elution can often lead to aggregation issues for these products. A concerted study of the kinetics of aggregate formation and their relation to chromatography on Protein A media has been lacking. This paper provides a framework to describe aggregation kinetics for an Fc fusion protein that was highly susceptible to aggregate formation under low pH conditions. In contrast to what is usually expected to be a higher order reaction, first order aggregation kinetics were observed for this protein over a wide range of conditions. A comparison of the rate constants of aggregation forms an effective means of comparing various stabilizing additives to the elution buffer with one another. Inclusion of urea in the elution buffer at moderate concentrations (Protein A column were both found to be effective solutions to the aggregation issue. Elution from the Protein A resin was found to increase the aggregation rate constants over and above what would be expected from exposure to low pH conditions in solution alone. This demonstrates that Protein A-Fc interactions can destabilize product structure and increase the tendency to aggregate. The results presented here are anticipated to assist the development of Protein A process conditions for products that are prone to form high molecular weight aggregates during column elution.

  8. The actin cytoskeleton inhibits pore expansion during PIV5 fusion protein-promoted cell-cell fusion

    OpenAIRE

    Wurth, Mark A.; Schowalter, Rachel M.; Smith, Everett Clinton; Moncman, Carole L.; Dutch, Rebecca Ellis; McCann, Richard O.

    2010-01-01

    Paramyxovirus fusion (F) proteins promote both virus-cell fusion, required for viral entry, and cell-cell fusion, resulting in syncytia formation. We used the F-actin stabilizing drug, jasplakinolide, and the G-actin sequestrant, latrunculin A, to examine the role of actin dynamics in cell-cell fusion mediated by the parainfluenza virus 5 (PIV5) F protein. Jasplakinolide treatment caused a dose-dependent increase in cell-cell fusion as measured by both syncytia and reporter gene assays, and l...

  9. Molecular Determinants for Protein Stabilization by Insertional Fusion to a Thermophilic Host Protein.

    Science.gov (United States)

    Pierre, Brennal; Labonte, Jason W; Xiong, Tina; Aoraha, Edwin; Williams, Asher; Shah, Vandan; Chau, Edward; Helal, Kazi Yasin; Gray, Jeffrey J; Kim, Jin Ryoun

    2015-11-02

    A universal method that improves protein stability and evolution has thus far eluded discovery. Recently, however, studies have shown that insertional fusion to a protein chaperone stabilized various target proteins with minimal negative effects. The improved stability was derived from insertion into a hyperthermophilic protein, Pyrococcus furiosus maltodextrin-binding protein (PfMBP), rather than from changes to the target protein sequence. In this report, by evaluating the thermodynamic and kinetic stability of various inserted β-lactamase (BLA) homologues, we were able to examine the molecular determinants of stability realized by insertional fusion to PfMBP. Results indicated that enhanced stability and suppressed aggregation of BLA stemmed from enthalpic and entropic mechanisms. This report also suggests that insertional fusion to a stable protein scaffold has the potential to be a useful method for improving protein stability, as well as functional protein evolution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Regulation of Exocytotic Fusion Pores by SNARE Protein Transmembrane Domains

    Directory of Open Access Journals (Sweden)

    Zhenyong Wu

    2017-10-01

    Full Text Available Calcium-triggered exocytotic release of neurotransmitters and hormones from neurons and neuroendocrine cells underlies neuronal communication, motor activity and endocrine functions. The core of the neuronal exocytotic machinery is composed of soluble N-ethyl maleimide sensitive factor attachment protein receptors (SNAREs. Formation of complexes between vesicle-attached v- and plasma-membrane anchored t-SNAREs in a highly regulated fashion brings the membranes into close apposition. Small, soluble proteins called Complexins (Cpx and calcium-sensing Synaptotagmins cooperate to block fusion at low resting calcium concentrations, but trigger release upon calcium increase. A growing body of evidence suggests that the transmembrane domains (TMDs of SNARE proteins play important roles in regulating the processes of fusion and release, but the mechanisms involved are only starting to be uncovered. Here we review recent evidence that SNARE TMDs exert influence by regulating the dynamics of the fusion pore, the initial aqueous connection between the vesicular lumen and the extracellular space. Even after the fusion pore is established, hormone release by neuroendocrine cells is tightly controlled, and the same may be true of neurotransmitter release by neurons. The dynamics of the fusion pore can regulate the kinetics of cargo release and the net amount released, and can determine the mode of vesicle recycling. Manipulations of SNARE TMDs were found to affect fusion pore properties profoundly, both during exocytosis and in biochemical reconstitutions. To explain these effects, TMD flexibility, and interactions among TMDs or between TMDs and lipids have been invoked. Exocytosis has provided the best setting in which to unravel the underlying mechanisms, being unique among membrane fusion reactions in that single fusion pores can be probed using high-resolution methods. An important role will likely be played by methods that can probe single fusion pores

  11. Intracellular Delivery of Proteins via Fusion Peptides in Intact Plants.

    Directory of Open Access Journals (Sweden)

    Kiaw Kiaw Ng

    Full Text Available In current plant biotechnology, the introduction of exogenous DNA encoding desired traits is the most common approach used to modify plants. However, general plant transformation methods can cause random integration of exogenous DNA into the plant genome. To avoid these events, alternative methods, such as a direct protein delivery system, are needed to modify the plant. Although there have been reports of the delivery of proteins into cultured plant cells, there are currently no methods for the direct delivery of proteins into intact plants, owing to their hierarchical structures. Here, we demonstrate the efficient fusion-peptide-based delivery of proteins into intact Arabidopsis thaliana. Bovine serum albumin (BSA, 66 kDa was selected as a model protein to optimize conditions for delivery into the cytosol. The general applicability of our method to large protein cargo was also demonstrated by the delivery of alcohol dehydrogenase (ADH, 150 kDa into the cytosol. The compatibility of the fusion peptide system with the delivery of proteins to specific cellular organelles was also demonstrated using the fluorescent protein Citrine (27 kDa conjugated to either a nuclear localization signal (NLS or a peroxisomal targeting signal (PTS. In conclusion, our designed fusion peptide system can deliver proteins with a wide range of molecular weights (27 to 150 kDa into the cells of intact A. thaliana without interfering with the organelle-targeting peptide conjugated to the protein. We expect that this efficient protein delivery system will be a powerful tool in plant biotechnology.

  12. Oligomerization and toxicity of A{beta} fusion proteins

    Energy Technology Data Exchange (ETDEWEB)

    Caine, Joanne M., E-mail: Jo.Caine@csiro.au [CSIRO Materials Science and Engineering and the Preventive Health Flagship, Parkville, Victoria (Australia); Bharadwaj, Prashant R. [CSIRO Materials Science and Engineering and the Preventive Health Flagship, Parkville, Victoria (Australia); Centre for Excellence for Alzheimer' s Disease Research and Care, School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Western Australia (Australia); Sankovich, Sonia E. [CSIRO Materials Science and Engineering and the Preventive Health Flagship, Parkville, Victoria (Australia); Ciccotosto, Giuseppe D. [The Department of Pathology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010 (Australia); Streltsov, Victor A.; Varghese, Jose [CSIRO Materials Science and Engineering and the Preventive Health Flagship, Parkville, Victoria (Australia)

    2011-06-10

    Highlights: {yields} We expressed amyloid-{beta} (A{beta}) peptide as a soluble maltose binding protein fusion (MBP-A{beta}42 and MBP-A{beta}16). {yields} The full length A{beta} peptide fusion, MBP-A{beta}42, forms oligomeric species as determined by SDS-PAGE gels, gel filtration and DLS. {yields} The MBP-A{beta}42, but not MBP-A{beta}16 or MBP alone, is toxic to both yeast and mammalian cells as determined by toxicity assays. -- Abstract: This study has found that the Maltose binding protein A{beta}42 fusion protein (MBP-A{beta}42) forms soluble oligomers while the shorter MBP-A{beta}16 fusion and control MBP did not. MBP-A{beta}42, but neither MBP-A{beta}16 nor control MBP, was toxic in a dose-dependent manner in both yeast and primary cortical neuronal cells. This study demonstrates the potential utility of MBP-A{beta}42 as a reagent for drug screening assays in yeast and neuronal cell cultures and as a candidate for further A{beta}42 characterization.

  13. Engineering Globular Protein Vesicles through Tunable Self-Assembly of Recombinant Fusion Proteins.

    Science.gov (United States)

    Jang, Yeongseon; Choi, Won Tae; Heller, William T; Ke, Zunlong; Wright, Elizabeth R; Champion, Julie A

    2017-09-01

    Vesicles assembled from folded, globular proteins have potential for functions different from traditional lipid or polymeric vesicles. However, they also present challenges in understanding the assembly process and controlling vesicle properties. From detailed investigation of the assembly behavior of recombinant fusion proteins, this work reports a simple strategy to engineer protein vesicles containing functional, globular domains. This is achieved through tunable self-assembly of recombinant globular fusion proteins containing leucine zippers and elastin-like polypeptides. The fusion proteins form complexes in solution via high affinity binding of the zippers, and transition through dynamic coacervates to stable hollow vesicles upon warming. The thermal driving force, which can be tuned by protein concentration or temperature, controls both vesicle size and whether vesicles are single or bi-layered. These results provide critical information to engineer globular protein vesicles via self-assembly with desired size and membrane structure. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. The actin cytoskeleton inhibits pore expansion during PIV5 fusion protein-promoted cell-cell fusion

    International Nuclear Information System (INIS)

    Wurth, Mark A.; Schowalter, Rachel M.; Smith, Everett Clinton; Moncman, Carole L.; Ellis Dutch, Rebecca; McCann, Richard O.

    2010-01-01

    Paramyxovirus fusion (F) proteins promote both virus-cell fusion, required for viral entry, and cell-cell fusion, resulting in syncytia formation. We used the F-actin stabilizing drug, jasplakinolide, and the G-actin sequestrant, latrunculin A, to examine the role of actin dynamics in cell-cell fusion mediated by the parainfluenza virus 5 (PIV5) F protein. Jasplakinolide treatment caused a dose-dependent increase in cell-cell fusion as measured by both syncytia and reporter gene assays, and latrunculin A treatment also resulted in fusion stimulation. Treatment with jasplakinolide or latrunculin A partially rescued a fusion pore opening defect caused by deletion of the PIV5 F protein cytoplasmic tail, but these drugs had no effect on fusion inhibited at earlier stages by either temperature arrest or by a PIV5 heptad repeat peptide. These data suggest that the cortical actin cytoskeleton is an important regulator of fusion pore enlargement, an energetically costly stage of viral fusion protein-mediated membrane merger.

  15. Human MAP Tau Based Targeted Cytolytic Fusion Proteins

    Directory of Open Access Journals (Sweden)

    Olusiji A. Akinrinmade

    2017-06-01

    Full Text Available Some of the most promising small molecule toxins used to generate antibody drug conjugates (ADCs include anti-mitotic agents (e.g., auristatin and its derivatives which are designed to attack cancerous cells at their most vulnerable state during mitosis. We were interested in identifying a human cystostatic protein eventually showing comparable activities and allowing the generation of corresponding targeted fully human cytolytic fusion proteins. Recently, we identified the human microtubule associated protein tau (MAP tau, which binds specifically to tubulin and modulates the stability of microtubules, thereby blocking mitosis and presumably vesicular transport. By binding and stabilizing polymerized microtubule filaments, MAP tau-based fusion proteins skew microtubule dynamics towards cell cycle arrest and apoptosis. This biological activity makes rapidly proliferating cells (e.g., cancer and inflammatory cells an excellent target for MAP tau-based targeted treatments. Their superior selectivity for proliferating cells confers additional selectivity towards upregulated tumor-associated antigens at their surface, thereby preventing off-target related toxicity against normal cells bearing tumor-associated antigens at physiologically normal to low levels. In this review, we highlight recent findings on MAP tau-based targeted cytolytic fusion proteins reported in preclinical immunotherapeutic studies.

  16. Localization of somatostatin receptors at the light and electron microscopical level by using antibodies raised against fusion proteins

    DEFF Research Database (Denmark)

    Helboe, Lone; Møller, Morten

    2000-01-01

    Somatostatin, antibodies against somatostatin receptors, hypothalamus, Müller cells, fusion protein technique......Somatostatin, antibodies against somatostatin receptors, hypothalamus, Müller cells, fusion protein technique...

  17. Localization of a region in the fusion protein of avian metapneumovirus that modulates cell-cell fusion.

    Science.gov (United States)

    Wei, Yongwei; Feng, Kurtis; Yao, Xiangjie; Cai, Hui; Li, Junan; Mirza, Anne M; Iorio, Ronald M; Li, Jianrong

    2012-11-01

    The genus Metapneumovirus within the subfamily Pneumovirinae of the family Paramyxoviridae includes two members, human metapneumovirus (hMPV) and avian metapneumovirus (aMPV), causing respiratory tract infections in humans and birds, respectively. Paramyxoviruses enter host cells by fusing the viral envelope with a host cell membrane. Membrane fusion of hMPV appears to be unique, in that fusion of some hMPV strains requires low pH. Here, we show that the fusion (F) proteins of aMPV promote fusion in the absence of the attachment protein and low pH is not required. Furthermore, there are notable differences in cell-cell fusion among aMPV subtypes. Trypsin was required for cell-cell fusion induced by subtype B but not subtypes A and C. The F protein of aMPV subtype A was highly fusogenic, whereas those from subtypes B and C were not. By construction and evaluation of chimeric F proteins composed of domains from the F proteins of subtypes A and B, we localized a region composed of amino acid residues 170 to 338 in the F protein that is responsible for the hyperfusogenic phenotype of the F from subtype A. Further mutagenesis analysis revealed that residues R295, G297, and K323 in this region collectively contributed to the hyperfusogenicity. Taken together, we have identified a region in the aMPV F protein that modulates the extent of membrane fusion. A model for fusion consistent with these data is presented.

  18. Measles Virus Fusion Protein: Structure, Function and Inhibition

    Directory of Open Access Journals (Sweden)

    Philippe Plattet

    2016-04-01

    Full Text Available Measles virus (MeV, a highly contagious member of the Paramyxoviridae family, causes measles in humans. The Paramyxoviridae family of negative single-stranded enveloped viruses includes several important human and animal pathogens, with MeV causing approximately 120,000 deaths annually. MeV and canine distemper virus (CDV-mediated diseases can be prevented by vaccination. However, sub-optimal vaccine delivery continues to foster MeV outbreaks. Post-exposure prophylaxis with antivirals has been proposed as a novel strategy to complement vaccination programs by filling herd immunity gaps. Recent research has shown that membrane fusion induced by the morbillivirus glycoproteins is the first critical step for viral entry and infection, and determines cell pathology and disease outcome. Our molecular understanding of morbillivirus-associated membrane fusion has greatly progressed towards the feasibility to control this process by treating the fusion glycoprotein with inhibitory molecules. Current approaches to develop anti-membrane fusion drugs and our knowledge on drug resistance mechanisms strongly suggest that combined therapies will be a prerequisite. Thus, discovery of additional anti-fusion and/or anti-attachment protein small-molecule compounds may eventually translate into realistic therapeutic options.

  19. Expression and processing of fluorescent fusion proteins of amyloid precursor protein (APP).

    Science.gov (United States)

    Coughlan, Kathleen; Huang, Xiangping; He, Xiangyuan; Chung, Charlotte H Y; Li, Guangpu; Tang, Jordan

    2013-06-01

    Processing of β-amyloid precursor protein (APP) by β- and γ-secretases in neurons produces amyloid-β (Aβ), whose excess accumulation leads to Alzheimer's disease (AD). Knowledge on subcellular trafficking pathways of APP and its fragments is important for the understanding of AD pathogenesis. We designed fusion proteins comprising a C-terminal fragment of APP (app) and fluorescent proteins GFP (G) and DsRed (D) to permit the tracking of the fusion proteins and fragments in cells. CAD cells expressing these proteins emitted colocalized green and red fluorescence and produce ectodomains, sGapp and sRapp, and Aβ, whose level was reduced by inhibitors of β- and γ-secretases. The presence of GappR in endosomes was observed via colocalization with Rab5. These observations indicated that the fusion proteins were membrane inserted, transported in vesicles and proteolytically processed by the same mechanism for APP. By attenuating fusion protein synthesis with cycloheximide, individual fluorescent colors from the C-terminus of the fusion proteins appeared in the cytosol which was strongly suppressed by β-secretase inhibitor, suggesting that the ectodomains exit the cell rapidly (t1/2 about 20min) while the C-terminal fragments were retained longer in cells. In live cells, we observed the fluorescence of the ectodomains located between parental fusion proteins and plasma membrane, suggesting that these ectodomain positions are part of their secretion pathway. Our results indicate that the native ectodomain does not play a decisive role for the key features of APP trafficking and processing and the new fusion proteins may lead to novel insights in intracellular activities of APP. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Site-selective protein immobilization by covalent modification of GST fusion proteins.

    Science.gov (United States)

    Zhou, Yiqing; Guo, Tianlin; Tang, Guanghui; Wu, Hui; Wong, Nai-Kei; Pan, Zhengying

    2014-11-19

    The immobilization of functional proteins onto solid supports using affinity tags is an attractive approach in recent development of protein microarray technologies. Among the commonly used fusion protein tags, glutathione S-transferase (GST) proteins have been indispensable tools for protein-protein interaction studies and have extensive applications in recombinant protein purification and reversible protein immobilization. Here, by utilizing pyrimidine-based small-molecule probes with a sulfonyl fluoride reactive group, we report a novel and general approach for site-selective immobilization of Schistosoma japonicum GST (sjGST) fusion proteins through irreversible and specific covalent modification of the tyrosine-111 residue of the sjGST tag. As demonstrated by sjGST-tagged eGFP and sjGST-tagged kinase activity assays, this immobilization approach offers the advantages of high immobilization efficiency and excellent retention of protein structure and activity.

  1. Comparative immunoblot analysis with 10 different, partially overlapping recombinant fusion proteins derived from 5 different cytomegalovirus proteins

    NARCIS (Netherlands)

    van Zanten, J.; LAZZAROTTO, T; CAMPISI, B; VORNHAGEN, R; JAHN, G; LANDINI, MP; The, T. Hauw

    Ten fusion proteins derived from five various CMV encoded proteins were used for the detection of specific antibody response by immunoblot technique in sera from renal transplant recipients. The fusion proteins were derived from the following CMV specific proteins: the assembly protein ppUL80a with

  2. Heterologous production of peptides in plants: fusion proteins and beyond.

    Science.gov (United States)

    Viana, Juliane Flávia Cançado; Dias, Simoni Campos; Franco, Octávio Luiz; Lacorte, Cristiano

    2013-11-01

    Recombinant DNA technology has allowed the ectopic production of proteins and peptides of different organisms leading to biopharmaceutical production in large cultures of bacterial, yeasts and mammalian cells. Otherwise, the expression of recombinant proteins and peptides in plants is an attractive alternative presenting several advantages over the commonly used expression systems including reduced production costs, easy scale-up and reduced risks of pathogen contamination. Different types of proteins and peptides have been expressed in plants, including antibodies, antigens, and proteins and peptides of medical, veterinary and industrial applications. However, apart from providing a proof of concept, the use of plants as platforms for heterologous protein and peptide production still depends on key steps towards optimization including the enhancement of expression levels, manipulation of post-transcriptional modifications and improvements in purification methods. In this review, strategies to increase heterologous protein and peptide stability and accumulation are discussed, focusing on the expression of peptides through the use of gene fusions.

  3. Fusion protein is the main determinant of metapneumovirus host tropism.

    Science.gov (United States)

    de Graaf, Miranda; Schrauwen, Eefje J A; Herfst, Sander; van Amerongen, Geert; Osterhaus, Albert D M E; Fouchier, Ron A M

    2009-06-01

    Human metapneumovirus (HMPV) and avian metapneumovirus subgroup C (AMPV-C) infect humans and birds, respectively. This study confirmed the difference in host range in turkey poults, and analysed the contribution of the individual metapneumovirus genes to host range in an in vitro cell-culture model. Mammalian Vero-118 cells supported replication of both HMPV and AMPV-C in contrast to avian quail fibroblast (QT6) cells in which only AMPV-C replicated to high titres. Inoculation of Vero-118 and QT6 cells with recombinant HMPV in which genes were exchanged with those of AMPV-C revealed that the metapneumovirus fusion (F) protein is the main determinant for host tropism. Chimeric viruses in which polymerase complex proteins were exchanged between HMPV and AMPV-C replicated less efficiently compared with HMPV in QT6 cells. Using mini-genome systems, it was shown that exchanging these polymerase proteins resulted in reduced replication and transcription efficiency in QT6 cells. Examination of infected Vero-118 and QT6 cells revealed that viruses containing the F protein of AMPV-C yielded larger syncytia compared with viruses containing the HMPV F protein. Cell-content mixing assays revealed that the F protein of AMPV-C was more fusogenic compared with the F protein of HMPV, and that the F2 region is responsible for the difference observed between AMPV-C and HMPV F-promoted fusion in QT6 and Vero-118 cells. This study provides insight into the determinants of host tropism and membrane fusion of metapneumoviruses.

  4. In Situ Protein Binding Assay Using Fc-Fusion Proteins.

    Science.gov (United States)

    Padmanabhan, Nirmala; Siddiqui, Tabrez J

    2017-01-01

    This protocol describes an in situ protein-protein interaction assay between tagged recombinant proteins and cell-surface expressed synaptic proteins. The assay is arguably more sensitive than other traditional protein binding assays such as co-immunoprecipitation and pull-downs and provides a visual readout for binding. This assay has been widely used to determine the dissociation constant of binding of trans-synaptic adhesion proteins. The step-wise description in the protocol should facilitate the adoption of this method in other laboratories.

  5. Using Fluorescent Protein Fusions to Study Protein Subcellular Localization and Dynamics in Plant Cells.

    Science.gov (United States)

    Cui, Yong; Gao, Caiji; Zhao, Qiong; Jiang, Liwen

    2016-01-01

    Studies of protein subcellular localization and dynamics are helpful in understanding the cellular functions of proteins in an organism. In the past decade, the use of green fluorescent protein (GFP) as a fusion tag has dramatically extended our knowledge in this field. Transient expression and stable transformation of GFP-tagged proteins have been wildly used to study protein localization in vivo in different systems. Although GFP-based tags provide a fast and convenient way to characterize protein properties in living cells, several reports have demonstrated that GFP fusions might not accurately reflect the localization of the native protein as GFP tags may alter the protein properties. To facilitate proper usage of GFP tags in plant cell biology study, we describe detailed protocols to identify possible inhibitory effects of fluorescent tags on protein subcellular localization and to determine if a fluorescently tagged protein is localized to the correct subcellular compartment. Using Arabidopsis Endomembrane protein 12 (EMP12) as an example, we first show the possible inhibitory effect of GFP tags on proper protein localization and then describe the immunofluorescence labeling method to verify the correct localization of GFP fusion proteins. Next, a method is presented using the ImageJ program with the Pearson-Spearman correlation (PSC) colocalization plug-in for statistical quantification of colocalization ratios of two fluorophores. Finally we provide a detailed method for protein dynamics studies using spinning disk confocal microscopy in Arabidopsis cells.

  6. Protein-induced fusion can be modulated by target membrane lipids through a structural switch at the level of the fusion peptide

    NARCIS (Netherlands)

    Pecheur, EI; Martin, [No Value; Bienvenue, A; Ruysschaert, JM; Hoekstra, D

    2000-01-01

    Regulatory features of protein-induced membrane fusion are largely unclear, particularly at the level of the fusion peptide. Fusion peptides being part of larger protein complexes, such investigations are met with technical limitations. Here, we show that the fusion activity of influenza virus or

  7. Engineering Styrene Monooxygenase for Biocatalysis: Reductase-Epoxidase Fusion Proteins.

    Science.gov (United States)

    Heine, Thomas; Tucker, Kathryn; Okonkwo, Nonye; Assefa, Berhanegebriel; Conrad, Catleen; Scholtissek, Anika; Schlömann, Michael; Gassner, George; Tischler, Dirk

    2017-04-01

    The enantioselective epoxidation of styrene and related compounds by two-component styrene monooxygenases (SMOs) has targeted these enzymes for development as biocatalysts. In the present work, we prepare genetically engineered fusion proteins that join the C-terminus of the epoxidase (StyA) to the N-terminus of the reductase (StyB) through a linker peptide and demonstrate their utility as biocatalysts in the synthesis of Tyrain purple and other indigoid dyes. A single-vector expression system offers a simplified platform for transformation and expansion of the catalytic function of styrene monooxygenases, and the resulting fusion proteins are self-regulated and couple efficiently NADH oxidation to styrene epoxidation. We find that the reductase domain proceeds through a sequential ternary-complex mechanism at low FAD concentration and a double-displacement mechanism at higher concentrations of FAD. Single-turnover studies indicate an observed rate constant for FAD-to-FAD hydride transfer of ~8 s -1 . This step is rate limiting in the styrene epoxidation reaction and helps to ensure that flavin reduction and styrene epoxidation reactions proceed without wasteful side reactions. Comparison of the reductase activity of the fusion proteins with the naturally occurring reductase, SMOB, and N-terminally histidine-tagged reductase, NSMOB, suggests that the observed changes in catalytic mechanism are due in part to an increase in flavin-binding affinity associated with the N-terminal extension of the reductase.

  8. Functional Carboxy-Terminal Fluorescent Protein Fusion to Pseudorabies Virus Small Capsid Protein VP26.

    Science.gov (United States)

    Hogue, Ian B; Jean, Jolie; Esteves, Andrew D; Tanneti, Nikhila S; Scherer, Julian; Enquist, Lynn W

    2018-01-01

    Fluorescent protein fusions to herpesvirus capsids have proven to be a valuable method to study virus particle transport in living cells. Fluorescent protein fusions to the amino terminus of small capsid protein VP26 are the most widely used method to visualize pseudorabies virus (PRV) and herpes simplex virus (HSV) particles in living cells. However, these fusion proteins do not incorporate to full occupancy and have modest effects on virus replication and pathogenesis. Recent cryoelectron microscopy studies have revealed that herpesvirus small capsid proteins bind to capsids via their amino terminus, whereas the carboxy terminus is unstructured and therefore may better tolerate fluorescent protein fusions. Here, we describe a new recombinant PRV expressing a carboxy-terminal VP26-mCherry fusion. Compared to previously characterized viruses expressing amino-terminal fusions, this virus expresses more VP26 fusion protein in infected cells and incorporates more VP26 fusion protein into virus particles, and individual virus particles exhibit brighter red fluorescence. We performed single-particle tracking of fluorescent virus particles in primary neurons to measure anterograde and retrograde axonal transport, demonstrating the usefulness of this novel VP26-mCherry fusion for the study of viral intracellular transport. IMPORTANCE Alphaherpesviruses are among the very few viruses that are adapted to invade the mammalian nervous system. Intracellular transport of virus particles in neurons is important, as this process underlies both mild peripheral nervous system infection and severe spread to the central nervous system. VP26, the small capsid protein of HSV and PRV, was one of the first herpesvirus proteins to be fused to a fluorescent protein. Since then, these capsid-tagged virus mutants have become a powerful tool to visualize and track individual virus particles. Improved capsid tags will facilitate fluorescence microscopy studies of virus particle intracellular

  9. A novel Escherichia coli solubility enhancer protein for fusion expression of aggregation-prone heterologous proteins.

    Science.gov (United States)

    Song, Jong-Am; Lee, Dae-Sung; Park, Jin-Seung; Han, Kyung-Yeon; Lee, Jeewon

    2011-07-10

    Through the proteome analysis of Escherichia coli BL21(DE3), we previously identified the stress-responsive protein, arsenate reductase (ArsC), that showed a high cytoplasmic solubility and a folding capacity even in the presence of stress-inducing reagents. In this study, we used ArsC as an N-terminal fusion partner to synthesize nine aggregation-prone proteins as water-soluble forms. As a result, solubility of the aggregation-prone proteins increased dramatically by the fusion of ArsC, due presumably to its tendency to facilitate the folding of target proteins. Also, we evaluated and confirmed the efficacy of ArsC-fusion expression in making the fusion-expressed target proteins have their own native function or structure. That is, the self-assembly function of human ferritin light chain, l-arginine-degrading function of arginine deiminase, and the correct secondary structure of human granulocyte colony stimulating factor were clearly observed through transmission electron microscope analysis, colorimetric enzyme activity assay, and circular dichroism, respectively. It is strongly suggested that ArsC can be in general an efficient fusion expression partner for the production of soluble and active heterologous proteins in E. coli. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Protein accumulation and rumen stability of wheat γ-gliadin fusion proteins in tobacco and alfalfa.

    Science.gov (United States)

    Sun, Xiaodong; Chi-Ham, Cecilia L; Cohen-Davidyan, Tamar; DeBen, Christopher; Getachew, Girma; DePeters, Edward; Putnam, Daniel; Bennett, Alan

    2015-09-01

    The nutritional value of various crops can be improved by engineering plants to produce high levels of proteins. For example, because methionine deficiency limits the protein quality of Medicago Sativa (alfalfa) forage, producing alfalfa plants that accumulate high levels of a methionine-rich protein could increase the nutritional value of that crop. We used three strategies in designing methionine-rich recombinant proteins that could accumulate to high levels in plants and thereby serve as candidates for improving the protein quality of alfalfa forage. In tobacco, two fusion proteins, γ-gliadin-δ-zein and γ-δ-zein, as well as δ-zein co-expressed with β-zein, all formed protein bodies. However, the γ-gliadin-δ-zein fusion protein accumulated to the highest level, representing up to 1.5% of total soluble protein (TSP) in one transformant. In alfalfa, γ-gliadin-δ-zein accumulated to 0.2% of TSP, and in an in vitro rumen digestion assay, γ-gliadin-δ-zein was more resistant to microbial degradation than Rubisco. Additionally, although it did not form protein bodies, a γ-gliadin-GFP fusion protein accumulated to much higher levels, 7% of TSP, than a recombinant protein comprised of an ER localization signal fused to GFP in tobacco. Based on our results, we conclude that γ-gliadin-δ-zein is a potential candidate protein to use for enhancing methionine levels in plants and for improving rumen stability of forage protein. γ-gliadin fusion proteins may provide a general platform for increasing the accumulation of recombinant proteins in transgenic plants. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  11. Structure and Function Study of HIV and Influenza Fusion Proteins

    Science.gov (United States)

    Liang, Shuang

    Human immunodeficiency virus (HIV) and influenza virus are membrane-enveloped viruses causing acquired immunodeficiency syndrome (AIDS) and flu. The initial step of HIV and influenza virus infection is fusion between viral and host cell membrane catalyzed by the viral fusion protein gp41 and hemagglutinin (HA) respectively. However, the structure of gp41 and HA as well as the infection mechanism are still not fully understood. This work addresses (1) full length gp41 ectodomain and TM domain structure and function and (2) IFP membrane location and IFP-membrane interaction. My studies of gp41 protein and IFP can provide better understanding of the membrane fusion mechanism and may aid development of anti-viral therapeutics and vaccine. The full length ectodomain and transmembrane domain of gp41 and shorter constructs were expressed, purified and solubilized at physiology conditions. The constructs adopt overall alpha helical structure in SDS and DPC detergents, and showed hyperthermostability with Tm > 90 °C. The oligomeric states of these proteins vary in different detergent buffer: predominant trimer for all constructs and some hexamer fraction for HM and HM_TM protein in SDS at pH 7.4; and mixtures of monomer, trimer, and higher-order oligomer protein in DPC at pH 4.0 and 7.4. Substantial protein-induced vesicle fusion was observed, including fusion of neutral vesicles at neutral pH, which are the conditions similar HIV/cell fusion. Vesicle fusion by a gp41 ectodomain construct has rarely been observed under these conditions, and is aided by inclusion of both the FP and TM, and by protein which is predominantly trimer rather than monomer. Current data was integrated with existing data, and a structural model was proposed. Secondary structure and conformation of IFP is a helix-turn-helix structure in membrane. However, there has been arguments about the IFP membrane location. 13C-2H REDOR solid-state NMR is used to solve this problem. The IFP adopts major alpha

  12. Intracellular distribution of cowpea mosaic virus movement protein as visualised by green fluorescent protein fusions

    NARCIS (Netherlands)

    Gopinath, K.; Bertens, P.; Pouwels, J.; Marks, H.; Lent, van J.W.M.; Wellink, J.E.; Kammen, van A.

    2003-01-01

    Cowpea mosaic virus (CPMV) derivatives expressing movement protein (MP) green fluorescent protein (GFP) fusions (MP:GFP) were used to study the intracellular targeting and localization of the MP in cowpea protoplasts and plants. In protoplasts, a virus coding for a wild type MP:GFP (MPfGFP) induced

  13. Trimeric transmembrane domain interactions in paramyxovirus fusion proteins: roles in protein folding, stability, and function.

    Science.gov (United States)

    Smith, Everett Clinton; Smith, Stacy E; Carter, James R; Webb, Stacy R; Gibson, Kathleen M; Hellman, Lance M; Fried, Michael G; Dutch, Rebecca Ellis

    2013-12-13

    Paramyxovirus fusion (F) proteins promote membrane fusion between the viral envelope and host cell membranes, a critical early step in viral infection. Although mutational analyses have indicated that transmembrane (TM) domain residues can affect folding or function of viral fusion proteins, direct analysis of TM-TM interactions has proved challenging. To directly assess TM interactions, the oligomeric state of purified chimeric proteins containing the Staphylococcal nuclease (SN) protein linked to the TM segments from three paramyxovirus F proteins was analyzed by sedimentation equilibrium analysis in detergent and buffer conditions that allowed density matching. A monomer-trimer equilibrium best fit was found for all three SN-TM constructs tested, and similar fits were obtained with peptides corresponding to just the TM region of two different paramyxovirus F proteins. These findings demonstrate for the first time that class I viral fusion protein TM domains can self-associate as trimeric complexes in the absence of the rest of the protein. Glycine residues have been implicated in TM helix interactions, so the effect of mutations at Hendra F Gly-508 was assessed in the context of the whole F protein. Mutations G508I or G508L resulted in decreased cell surface expression of the fusogenic form, consistent with decreased stability of the prefusion form of the protein. Sedimentation equilibrium analysis of TM domains containing these mutations gave higher relative association constants, suggesting altered TM-TM interactions. Overall, these results suggest that trimeric TM interactions are important driving forces for protein folding, stability and membrane fusion promotion.

  14. Localization of a Region in the Fusion Protein of Avian Metapneumovirus That Modulates Cell-Cell Fusion

    Science.gov (United States)

    Wei, Yongwei; Feng, Kurtis; Yao, Xiangjie; Cai, Hui; Li, Junan; Mirza, Anne M.; Iorio, Ronald M.

    2012-01-01

    The genus Metapneumovirus within the subfamily Pneumovirinae of the family Paramyxoviridae includes two members, human metapneumovirus (hMPV) and avian metapneumovirus (aMPV), causing respiratory tract infections in humans and birds, respectively. Paramyxoviruses enter host cells by fusing the viral envelope with a host cell membrane. Membrane fusion of hMPV appears to be unique, in that fusion of some hMPV strains requires low pH. Here, we show that the fusion (F) proteins of aMPV promote fusion in the absence of the attachment protein and low pH is not required. Furthermore, there are notable differences in cell-cell fusion among aMPV subtypes. Trypsin was required for cell-cell fusion induced by subtype B but not subtypes A and C. The F protein of aMPV subtype A was highly fusogenic, whereas those from subtypes B and C were not. By construction and evaluation of chimeric F proteins composed of domains from the F proteins of subtypes A and B, we localized a region composed of amino acid residues 170 to 338 in the F protein that is responsible for the hyperfusogenic phenotype of the F from subtype A. Further mutagenesis analysis revealed that residues R295, G297, and K323 in this region collectively contributed to the hyperfusogenicity. Taken together, we have identified a region in the aMPV F protein that modulates the extent of membrane fusion. A model for fusion consistent with these data is presented. PMID:22915815

  15. Fusion expression of Helicobacter pylori neutrophil-activating protein in E.coli

    OpenAIRE

    Kang, Qiao-Zhen; Duan, Guang-Cai; Fan, Qing-Tang; Xi, Yuan-Lin

    2005-01-01

    AIM: To produce a recombinant protein rMBP-NAP, which was fusionally expressed by Helicobacter pylori (H pylori) neutrophil-activating protein (NAP) and E. coli maltose-binding protein (MBP) and to evaluate its immunoreactivity and immunogenicity.

  16. Polyionic and cysteine-containing fusion peptides as versatile protein tags.

    Science.gov (United States)

    Lilie, Hauke; Richter, Susanne; Bergelt, Sabine; Frost, Stefan; Gehle, Franziska

    2013-08-01

    In response to advances in proteomics research and the use of proteins in medical and biotechnological applications, recombinant protein production and the design of specific protein characteristics and functions has become a widely used technology. In this context, protein fusion tags have been developed as indispensable tools for protein expression, purification, and the design of functionalized surfaces or artificially bifunctional proteins. Here we summarize how positively or negatively charged polyionic fusion peptides with or without an additional cysteine can be used as protein tags for protein expression and purification, for matrix-assisted refolding of aggregated protein, and for coupling of proteins either to technologically relevant matrices or to other proteins. In this context we used cysteine-containing polyionic fusion peptides for the design of immunotoxins. In general, polyionic fusion tags can be considered as a multifunctional module in protein technology.

  17. The MARVEL domain protein, Singles Bar, is required for progression past the pre-fusion complex stage of myoblast fusion.

    Science.gov (United States)

    Estrada, Beatriz; Maeland, Anne D; Gisselbrecht, Stephen S; Bloor, James W; Brown, Nicholas H; Michelson, Alan M

    2007-07-15

    Multinucleated myotubes develop by the sequential fusion of individual myoblasts. Using a convergence of genomic and classical genetic approaches, we have discovered a novel gene, singles bar (sing), that is essential for myoblast fusion. sing encodes a small multipass transmembrane protein containing a MARVEL domain, which is found in vertebrate proteins involved in processes such as tight junction formation and vesicle trafficking where--as in myoblast fusion--membrane apposition occurs. sing is expressed in both founder cells and fusion competent myoblasts preceding and during myoblast fusion. Examination of embryos injected with double-stranded sing RNA or embryos homozygous for ethane methyl sulfonate-induced sing alleles revealed an identical phenotype: replacement of multinucleated myofibers by groups of single, myosin-expressing myoblasts at a stage when formation of the mature muscle pattern is complete in wild-type embryos. Unfused sing mutant myoblasts form clusters, suggesting that early recognition and adhesion of these cells are unimpaired. To further investigate this phenotype, we undertook electron microscopic ultrastructural studies of fusing myoblasts in both sing and wild-type embryos. These experiments revealed that more sing mutant myoblasts than wild-type contain pre-fusion complexes, which are characterized by electron-dense vesicles paired on either side of the fusing plasma membranes. In contrast, embryos mutant for another muscle fusion gene, blown fuse (blow), have a normal number of such complexes. Together, these results lead to the hypothesis that sing acts at a step distinct from that of blow, and that sing is required on both founder cell and fusion-competent myoblast membranes to allow progression past the pre-fusion complex stage of myoblast fusion, possibly by mediating fusion of the electron-dense vesicles to the plasma membrane.

  18. Side chain packing below the fusion peptide strongly modulates triggering of the Hendra virus F protein.

    Science.gov (United States)

    Smith, Everett Clinton; Dutch, Rebecca Ellis

    2010-10-01

    Triggering of the Hendra virus fusion (F) protein is required to initiate the conformational changes which drive membrane fusion, but the factors which control triggering remain poorly understood. Mutation of a histidine predicted to lie near the fusion peptide to alanine greatly reduced fusion despite wild-type cell surface expression levels, while asparagine substitution resulted in a moderate restoration in fusion levels. Slowed kinetics of six-helix bundle formation, as judged by sensitivity to heptad repeat B-derived peptides, was observed for all H372 mutants. These data suggest that side chain packing beneath the fusion peptide is an important regulator of Hendra virus F triggering.

  19. A toolkit for graded expression of green fluorescent protein fusion proteins in mammalian cells.

    Science.gov (United States)

    Nalaskowski, Marcus M; Ehm, Patrick; Giehler, Susanne; Mayr, Georg W

    2012-09-01

    Green fluorescent protein (GFP) and GFP-like proteins of different colors are important tools in cell biology. In many studies, the intracellular targeting of proteins has been determined by transiently expressing GFP fusion proteins and analyzing their intracellular localization by fluorescence microscopy. In most vectors, expression of GFP is driven by the enhancer/promoter cassette of the immediate early gene of human cytomegalovirus (hCMV). This cassette generates high levels of protein expression in most mammalian cell lines. Unfortunately, these nonphysiologically high protein levels have been repeatedly reported to artificially alter the intracellular targeting of proteins fused to GFP. To cope with this problem, we generated a multitude of attenuated GFP expression vectors by modifying the hCMV enhancer/promoter cassette. These modified vectors were transiently expressed, and the expression levels of enhanced green fluorescent protein (EGFP) alone and enhanced yellow fluorescent protein (EYFP) fused to another protein were determined by fluorescence microscopy and/or Western blotting. As shown in this study, we were able to (i) clearly reduce the expression of EGFP alone and (ii) reduce expression of an EYFP fusion protein down to the level of the endogenous protein, both in a graded manner. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Immobilization and purification of enzymes with staphylococcal protein A gene fusion vectors.

    OpenAIRE

    Nilsson, B; Abrahmsén, L; Uhlén, M

    1985-01-01

    Two improved plasmid vectors, containing the gene coding for staphylococcal protein A and adapted for gene fusions, have been constructed. These vectors allow fusion of any gene to the protein A moiety, giving fusion proteins which can be purified, in a one-step procedure by IgG affinity chromatography. One vector, pRIT2, is designed for temperature-inducible expression of intracellular fusion proteins in Escherichia coli and the other pRIT5, is a shuttle vector designed for secretion. The la...

  1. Protein fold recognition using geometric kernel data fusion.

    Science.gov (United States)

    Zakeri, Pooya; Jeuris, Ben; Vandebril, Raf; Moreau, Yves

    2014-07-01

    Various approaches based on features extracted from protein sequences and often machine learning methods have been used in the prediction of protein folds. Finding an efficient technique for integrating these different protein features has received increasing attention. In particular, kernel methods are an interesting class of techniques for integrating heterogeneous data. Various methods have been proposed to fuse multiple kernels. Most techniques for multiple kernel learning focus on learning a convex linear combination of base kernels. In addition to the limitation of linear combinations, working with such approaches could cause a loss of potentially useful information. We design several techniques to combine kernel matrices by taking more involved, geometry inspired means of these matrices instead of convex linear combinations. We consider various sequence-based protein features including information extracted directly from position-specific scoring matrices and local sequence alignment. We evaluate our methods for classification on the SCOP PDB-40D benchmark dataset for protein fold recognition. The best overall accuracy on the protein fold recognition test set obtained by our methods is ∼ 86.7%. This is an improvement over the results of the best existing approach. Moreover, our computational model has been developed by incorporating the functional domain composition of proteins through a hybridization model. It is observed that by using our proposed hybridization model, the protein fold recognition accuracy is further improved to 89.30%. Furthermore, we investigate the performance of our approach on the protein remote homology detection problem by fusing multiple string kernels. The MATLAB code used for our proposed geometric kernel fusion frameworks are publicly available at http://people.cs.kuleuven.be/∼raf.vandebril/homepage/software/geomean.php?menu=5/. © The Author 2014. Published by Oxford University Press.

  2. Protein body formation in stable transgenic tobacco expressing elastin-like polypeptide and hydrophobin fusion proteins.

    Science.gov (United States)

    Gutiérrez, Sonia P; Saberianfar, Reza; Kohalmi, Susanne E; Menassa, Rima

    2013-05-10

    Plants are recognized as an efficient and inexpensive system to produce valuable recombinant proteins. Two different strategies have been commonly used for the expression of recombinant proteins in plants: transient expression mediated by Agrobacterium; or stable transformation of the plant genome. However, the use of plants as bioreactors still faces two main limitations: low accumulation levels of some recombinant proteins and lack of efficient purification methods. Elastin-like polypeptide (ELP), hydrophobin I (HFBI) and Zera® are three fusion partners found to increase the accumulation levels of recombinant proteins and induce the formation of protein bodies (PBs) in leaves when targeted to the endoplasmic reticulum (ER) in transient expression assays. In this study the effects of ELP and HFBI fusion tags on recombinant protein accumulation levels and PB formation was examined in stable transgenic Nicotiana tabacum. The accumulation of recombinant protein and PB formation was evaluated in two cultivars of Nicotiana tabacum transformed with green fluorescent protein (GFP) fused to ELP or HFBI, both targeted and retrieved to the ER. The ELP and HFBI tags increased the accumulation of the recombinant protein and induced the formation of PBs in leaves of stable transgenic plants from both cultivars. Furthermore, these tags induced the formation of PBs in a concentration-dependent manner, where a specific level of recombinant protein accumulation was required for PBs to appear. Moreover, agro-infiltration of plants accumulating low levels of recombinant protein with p19, a suppressor of post-transcriptional gene silencing (PTGS), increased accumulation levels in four independent transgenic lines, suggesting that PTGS might have caused the low accumulation levels in these plants. The use of ELP and HFBI tags as fusion partners in stable transgenic plants of tobacco is feasible and promising. In a constitutive environment, these tags increase the accumulation levels

  3. Enhancing recombinant protein solubility with ubiquitin-like small archeal modifying protein fusion partners.

    Science.gov (United States)

    Varga, Sándor; Pathare, Ganesh Ramnath; Baka, Erzsébet; Boicu, Marius; Kriszt, Balázs; Székács, András; Zinzula, Luca; Kukolya, József; Nagy, István

    2015-11-01

    A variety of protein expression tags with different biochemical properties has been used to enhance the yield and solubility of recombinant proteins. Ubiquitin, SUMO (small ubiquitin-like modifier) and prokaryotic ubiquitin like MoaD (molybdopterin synthase, small subunit) fusion tags are getting more popular because of their small size. In this paper we report on the use of ubiquitin-like small archaeal modifier proteins (SAMPs) as fusion tags since they proved to increase expression yield, stability and solubility in our experiments. Equally important, they did not co-purify with proteins of the expression host and there was information that their specific JAB1/MPN/Mov34 metalloenzyme (JAMM) protease can recognize the C-terminal VSGG sequence when SAMPs fused, either branched or linearly to target proteins, and cleave it specifically. SAMPs and JAMM proteases from Haloferax volcanii, Thermoplasma acidophilum, Methanococcoides burtonii and Nitrosopumilus maritimus were selected, cloned, expressed heterologously in Escherichia coli and tested as fusion tags and cleaving proteases, respectively. Investigated SAMPs enhanced protein expression and solubility on a wide scale. T. acidophilum SAMPs Ta0895 and Ta01019 were the best performing tags and their effect was comparable to the widely used maltose binding protein (MBP) and N utilization substance protein A (NusA) tags. Moreover, H. volcanii SAMP Hvo_2619 contribution was mediocre, whereas M. burtonii Mbur_1415 could not be expressed. Out of four investigated JAMM proteases, only Hvo_2505 could cleave fusion tags. Interestingly, it was found active not only on its own partner substrate Hvo_2619, but it also cleaved off Ta0895. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Complementation between avirulent Newcastle disease virus and a fusion protein gene expressed from a retrovirus vector: requirements for membrane fusion.

    OpenAIRE

    Morrison, T; McQuain, C; McGinnes, L

    1991-01-01

    The cDNA derived from the fusion gene of the virulent AV strain of Newcastle disease virus (NDV) was expressed in chicken embryo cells by using a retrovirus vector. The fusion protein expressed in this system was transported to the cell surface and was efficiently cleaved into the disulfide-linked F1-F2 form found in infectious virions. The cells expressing the fusion gene grew normally and could be passaged many times. Monolayers of these cells would plaque, in the absence of trypsin, avirul...

  5. LocFuse: human protein-protein interaction prediction via classifier fusion using protein localization information.

    Science.gov (United States)

    Zahiri, Javad; Mohammad-Noori, Morteza; Ebrahimpour, Reza; Saadat, Samaneh; Bozorgmehr, Joseph H; Goldberg, Tatyana; Masoudi-Nejad, Ali

    2014-12-01

    Protein-protein interaction (PPI) detection is one of the central goals of functional genomics and systems biology. Knowledge about the nature of PPIs can help fill the widening gap between sequence information and functional annotations. Although experimental methods have produced valuable PPI data, they also suffer from significant limitations. Computational PPI prediction methods have attracted tremendous attentions. Despite considerable efforts, PPI prediction is still in its infancy in complex multicellular organisms such as humans. Here, we propose a novel ensemble learning method, LocFuse, which is useful in human PPI prediction. This method uses eight different genomic and proteomic features along with four types of different classifiers. The prediction performance of this classifier selection method was found to be considerably better than methods employed hitherto. This confirms the complex nature of the PPI prediction problem and also the necessity of using biological information for classifier fusion. The LocFuse is available at: http://lbb.ut.ac.ir/Download/LBBsoft/LocFuse. The results revealed that if we divide proteome space according to the cellular localization of proteins, then the utility of some classifiers in PPI prediction can be improved. Therefore, to predict the interaction for any given protein pair, we can select the most accurate classifier with regard to the cellular localization information. Based on the results, we can say that the importance of different features for PPI prediction varies between differently localized proteins; however in general, our novel features, which were extracted from position-specific scoring matrices (PSSMs), are the most important ones and the Random Forest (RF) classifier performs best in most cases. LocFuse was developed with a user-friendly graphic interface and it is freely available for Linux, Mac OSX and MS Windows operating systems. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Fluorescent IgG fusion proteins made in E. coli.

    Science.gov (United States)

    Luria, Yael; Raichlin, Dina; Benhar, Itai

    2012-01-01

    Antibodies are among the most powerful tools in biological and biomedical research and are presently the fastest growing category of new bio-pharmaceutics. The most common format of antibody applied for therapeutic, diagnostic and analytical purposes is the IgG format. For medical applications, recombinant IgGs are made in cultured mammalian cells in a process that is too expensive to be considered for producing antibodies for diagnostic and analytical purposes. Therefore, for such purposes, mouse monoclonal antibodies or polyclonal sera from immunized animals are used. While looking for an easier and more rapid way to prepare full-length IgGs for therapeutic purposes, we recently developed and reported an expression and purification protocol for full-length IgGs, and IgG-based fusion proteins in E. coli, called "Inclonals." By applying the Inclonals technology, we could generate full-length IgGs that are genetically fused to toxins. The aim of the study described herein was to evaluate the possibility of applying the "Inclonals" technology for preparing IgG-fluorophore fusion proteins. We found that IgG fused to the green fluorescent proteins enhanced GFP (EGFP) while maintaining functionality in binding, lost most of its fluorescence during the refolding process. In contrast, we found that green fluorescent Superfolder GFP (SFGFP)-fused IgG and red fluorescent mCherry-fused IgG were functional in antigen binding and maintained fluorescence intensity. In addition, we found that we can link several SFGFPs in tandem to each IgG, with fluorescence intensity increasing accordingly. Fluorescent IgGs made in E. coli may become attractive alternatives to monoclonal or polyclonal fluorescent antibodies derived from animals.

  7. Fusion

    International Nuclear Information System (INIS)

    Naraghi, M.

    1976-01-01

    It is proposed that Iran as a world's potential supplier of fossile fuel should participate in fusion research and gain experience in this new field. Fusion, as an ultimate source of energy in future, and the problems concerned with the fusion reactors are reviewed. Furthermore; plasma heating, magnetic and inertial confinement in a fusion reactor are discussed. A brief description of tokamak, theta pinch and magnetic mirror reactors is also included

  8. Heat-shock protein fusion vectors for improved expression of soluble recombinant proteins in Escherichia coli.

    Science.gov (United States)

    Kyratsous, Christos A; Panagiotidis, Christos A

    2012-01-01

    Molecular chaperones or heat-shock proteins (HSPs) are protein machines that interact with unfolded or partially folded polypeptides and assist them in attaining their proper conformation. The folding reaction relies on a complex array of scaffolding effects and ATP-driven conformational changes that mediate the temporary unfolding and subsequent refolding of protein substrates. DnaK and GroEL are the two major Escherichia coli chaperones. They belong to the HSP70 and HSP60 families of proteins, respectively, and play a major role in protein folding. Here, we describe a set of bacterial expression vectors that permits the fusion of a protein of interest to DnaK or GroEL and its subsequent quantitative expression in a soluble, easily purifiable form. We also provide a set of compatible co-chaperone expression constructs that permit the simultaneous co-expression of the DnaK and GroEL physiological partners to further increase protein solubility. The system was successfully tested using the murine prion protein (PrP). Although PrP is normally insoluble when expressed in E. coli, we show that utilizing our vectors it can be produced in a soluble form as a DnaK or GroEL fusion. This system is useful for the production of a large array of proteins that fail to fold properly when expressed in E. coli.

  9. Molecular Principles of Gene Fusion Mediated Rewiring of Protein Interaction Networks in Cancer.

    Science.gov (United States)

    Latysheva, Natasha S; Oates, Matt E; Maddox, Louis; Flock, Tilman; Gough, Julian; Buljan, Marija; Weatheritt, Robert J; Babu, M Madan

    2016-08-18

    Gene fusions are common cancer-causing mutations, but the molecular principles by which fusion protein products affect interaction networks and cause disease are not well understood. Here, we perform an integrative analysis of the structural, interactomic, and regulatory properties of thousands of putative fusion proteins. We demonstrate that genes that form fusions (i.e., parent genes) tend to be highly connected hub genes, whose protein products are enriched in structured and disordered interaction-mediating features. Fusion often results in the loss of these parental features and the depletion of regulatory sites such as post-translational modifications. Fusion products disproportionately connect proteins that did not previously interact in the protein interaction network. In this manner, fusion products can escape cellular regulation and constitutively rewire protein interaction networks. We suggest that the deregulation of central, interaction-prone proteins may represent a widespread mechanism by which fusion proteins alter the topology of cellular signaling pathways and promote cancer. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  10. The coronavirus spike protein : mechanisms of membrane fusion and virion incorporation

    NARCIS (Netherlands)

    Bosch, B.J.

    2004-01-01

    The coronavirus spike protein is a membrane-anchored glycoprotein responsible for virus-cell attachment and membrane fusion, prerequisites for a successful virus infection. In this thesis, two aspects are described regarding the molecular biology of the coronavirus spike protein: its membrane fusion

  11. HUWE1 and TRIP12 Collaborate in Degradation of Ubiquitin-Fusion Proteins and Misframed Ubiquitin

    DEFF Research Database (Denmark)

    Poulsen, Esben G; Steinhauer, Cornelia; Lees, Michael

    2012-01-01

    In eukaryotic cells an uncleavable ubiquitin moiety conjugated to the N-terminus of a protein signals the degradation of the fusion protein via the proteasome-dependent ubiquitin fusion degradation (UFD) pathway. In yeast the molecular mechanism of the UFD pathway has been well characterized. Rec...

  12. Fusion

    CERN Document Server

    Mahaffey, James A

    2012-01-01

    As energy problems of the world grow, work toward fusion power continues at a greater pace than ever before. The topic of fusion is one that is often met with the most recognition and interest in the nuclear power arena. Written in clear and jargon-free prose, Fusion explores the big bang of creation to the blackout death of worn-out stars. A brief history of fusion research, beginning with the first tentative theories in the early 20th century, is also discussed, as well as the race for fusion power. This brand-new, full-color resource examines the various programs currently being funded or p

  13. Study on Fusion Protein and Its gene in Baculovirus Specificity

    International Nuclear Information System (INIS)

    Nemr, W.A.H.

    2012-01-01

    Baculoviruses are subdivided into two groups depending on the type of budded virus envelop fusion protein; group I utilized gp64 which include the most of nucleopolyhedroviruses (NPVs), group II utilized F protein which include the remnants of NPVs and all Granuloviruses (GVs). Recent studies reported the viral F protein coding gene as a host cellular sourced gene and may evolutionary acquired from the host genome referring to phylogeny analysis of fusion proteins. Thus, it was deduced that F protein coding gene is species- specific nucleotide sequence related to the type of the specific host and if virus could infect an unexpected host, the resulted virus may encode a vary F gene. In this regard, the present study utilized the mentioned properties of F gene in an attempt to produce a model of specific and more economic wider range granulovirus bio- pesticide able to infect both Spodoptera littoralis and Phthorimaea operculella larvae. Multiple sequence alignment and phylogeny analysis were performed on six members of group II baculovirus, novel universal PCR primers were manually designed from the conserved regions in the alignment graph, targeted to amplify species- specific sequence entire F gene open reading frame (ORF) which is useful in molecular identification of baculovirus in unknown samples. So, the PCR product of SpliGV used to prepare a specific probe for the F gene of this type of virus. Results reflected that it is possible to infect S. littoralis larvae by PhopGV if injected into larval haemocoel, the resulted virus of this infection showed by using DNA hybridization technique to be encode to F gene homologous with the F gene of Spli GV, which is revealed that the resulted virus acquired this F gene sequence from the host genome after infection. Consequently, these results may infer that if genetic aberrations occur in the host genome, this may affect in baculoviral infectivity. So, this study aimed to investigate the effect of gamma radiation at

  14. Protein kinase A-dependent transactivation by the E2A-Pbx1 fusion protein.

    Science.gov (United States)

    Ogo, A; Waterman, M R; Kamps, M P; Kagawa, N

    1995-10-27

    The chimeric gene E2A-PBX1 is formed by the t(1;19) chromosomal translocation exclusively associated with pediatric pre-B cell acute lymphoblastic leukemia (pre-B ALL). The resultant fusion protein from this chimeric gene contains the DNA-binding homeodomain of Pbx1. The first and only functional Pbx1 binding site has been localized in bovine CYP17 to a sequence (CRS1) that participates in cAMP-dependent transcription of this gene encoding the steroid hydroxylase, 17 alpha-hydroxylase cytochrome P450. Because Pbx1 is not expressed in pre-B cells, it may be possible that the E2a-Pbx1 fusion protein expressed in pre-B cells having this translocation will activate, in response to cAMP, transcription of genes not normally expressed in these cells leading to arrest of differentiation at the pre-B cell stage. We have now shown that reporter genes comprising CRS1 are activated transcriptionally by protein kinase A (PKA) in the pre-B cell line 697, which endogenously expresses the fusion protein, and that overexpression of E2A-Pbx1 in additional cell lines enhances transcription of reporter genes in a PKA-dependent fashion. Thus, it seems plausible that arrest in the pre-B stage leading to pre-B ALL includes cAMP-dependent activation of E2A-Pbx1.

  15. Protein knockouts in living eukaryotes using deGradFP and green fluorescent protein fusion targets.

    Science.gov (United States)

    Caussinus, Emmanuel; Kanca, Oguz; Affolter, Markus

    2013-09-24

    This unit describes deGradFP (degrade Green Fluorescent Protein), an easy-to-implement protein knockout method applicable in any eukaryotic genetic system. Depleting a protein in order to study its function in a living organism is usually achieved at the gene level (genetic mutations) or at the RNA level (RNA interference and morpholinos). However, any system that acts upstream of the proteic level depends on the turnover rate of the existing target protein, which can be extremely slow. In contrast, deGradFP is a fast method that directly depletes GFP fusion proteins. In particular, deGradFP is able to counteract maternal effects in embryos and causes early and fast onset loss-of-function phenotypes of maternally contributed proteins. Copyright © 2013 John Wiley & Sons, Inc.

  16. Elastin-like-polypeptide based fusion proteins for osteogenic factor delivery in bone healing.

    Science.gov (United States)

    McCarthy, Bryce; Yuan, Yuan; Koria, Piyush

    2016-07-08

    Modern treatments of bone injuries and diseases are becoming increasingly dependent on the usage of growth factors to stimulate bone growth. Bone morphogenetic protein-2 (BMP-2), a potent osteogenic inductive protein, exhibits promising results in treatment models, but recently has had its practical efficacy questioned due to the lack of local retention, ectopic bone formation, and potentially lethal inflammation. Where a new delivery technique of the BMP-2 is necessary, here we demonstrate the viability of an elastin-like peptide (ELP) fusion protein containing BMP-2 for delivery of the BMP-2. This fusion protein retains the performance characteristics of both the BMP-2 and ELP. The fusion protein was found to induce osteogenic differentiation of mesenchymal stem cells as evidenced by the production of alkaline phosphatase and extracellular calcium deposits in response to treatment by the fusion protein. Retention of the ELPs inverse phase transition property has allowed for expression of the fusion protein within a bacterial host (such as Escherichia coli) and easy and rapid purification using inverse transition cycling. The fusion protein formed self-aggregating nanoparticles at human-body temperature. The data collected suggests the viability of these fusion protein nanoparticles as a dosage-efficient and location-precise noncytotoxic delivery vehicle for BMP-2 in bone treatment. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1029-1037, 2016. © 2016 American Institute of Chemical Engineers.

  17. Chaperone activity of human small heat shock protein-GST fusion proteins.

    Science.gov (United States)

    Arbach, Hannah; Butler, Caley; McMenimen, Kathryn A

    2017-07-01

    Small heat shock proteins (sHsps) are a ubiquitous part of the machinery that maintains cellular protein homeostasis by acting as molecular chaperones. sHsps bind to and prevent the aggregation of partially folded substrate proteins in an ATP-independent manner. sHsps are dynamic, forming an ensemble of structures from dimers to large oligomers through concentration-dependent equilibrium dissociation. Based on structural studies and mutagenesis experiments, it is proposed that the dimer is the smallest active chaperone unit, while larger oligomers may act as storage depots for sHsps or play additional roles in chaperone function. The complexity and dynamic nature of their structural organization has made elucidation of their chaperone function challenging. HspB1 and HspB5 are two canonical human sHsps that vary in sequence and are expressed in a wide variety of tissues. In order to determine the role of the dimer in chaperone activity, glutathione-S-transferase (GST) was genetically linked as a fusion protein to the N-terminus regions of both HspB1 and HspB5 (also known as Hsp27 and αB-crystallin, respectively) proteins in order to constrain oligomer formation of HspB1 and HspB5, by using GST, since it readily forms a dimeric structure. We monitored the chaperone activity of these fusion proteins, which suggest they primarily form dimers and monomers and function as active molecular chaperones. Furthermore, the two different fusion proteins exhibit different chaperone activity for two model substrate proteins, citrate synthase (CS) and malate dehydrogenase (MDH). GST-HspB1 prevents more aggregation of MDH compared to GST-HspB5 and wild type HspB1. However, when CS is the substrate, both GST-HspB1 and GST-HspB5 are equally effective chaperones. Furthermore, wild type proteins do not display equal activity toward the substrates, suggesting that each sHsp exhibits different substrate specificity. Thus, substrate specificity, as described here for full-length GST

  18. [Expression and characterization of recombinant Sj23HD-HSA fusion protein in Saccharomyces cerevisiae].

    Science.gov (United States)

    Zhang, Wei; Yu, Chuan-Xin; Yang, Jian-Linag; Feng, Wei; Yin, Xu-Ren; Song, Li-Jun; Wang, Jie; Qian, Chun-Yan; Ke, Xue-Dan

    2011-12-01

    To prepare the fusion protein of large hydrophilic domain of 23 kDa membrane protein of Schistosoma japonicum and the mature peptide of human serum albumin (Sj23HD-HSA) and investigate its immunoreactivity. A fusion protein gene encoding Sj23HD-HSA fusion protein was prepared by overlapping PCR, which was confirmed by TA cloning and DNA sequencing. The fusion gene of Sj23HD-HSA was directionally subcloned into yeast expression plasmid pWX530 to construct a recombinant plasmid Sj23HD-HSA/pWX530. The transformants of Saccharomyces cerevisiae containing the recombinant plasmid Sj23HD-HSA/pWX530 were screened on leu deficient SD medium after yeast competent cells were transformed with recombinant plasmid. The excretive Sj23HD-HSA protein was expressed by culturing the yeast transformants at 30 degrees C for 1 week, and the protein component of culture supernatant was analyzed by SDS-PAGE. Sj23HD-HSA fusion protein was purified through Ion Exchange Chromatography. The immunoreactivity of recombinant Sj23HD-HSA fusion protein was determined by Western blotting with sera of schistosomiasis, clonorchiasis and healthy. The gene encoding the Sj23HD-HSA fusion protein was constructed successfully, which was confirmed by DNA sequencing. The yeast transformants containing plasmid Sj23HD-HSA/pWX530 could express the excretive Sj23HD-HSA fusion protein without inducing. The results of Western blotting indicated Sj23HD-HSA could be recognized by the sera of schistosomiasis, but could not be recognized by the sera of clonorchiasis and healthy respectively. Sj23HD-HSA fusion protein with good immune reactivity is prepared successfully, which will be a potential antigen for schistosomiasis immunodiagnosis.

  19. The fusion partner specifies the oncogenic potential of NUP98 fusion proteins.

    Science.gov (United States)

    Saw, Jesslyn; Curtis, David J; Hussey, Damian J; Dobrovic, Alexander; Aplan, Peter D; Slape, Christopher I

    2013-12-01

    NUP98 is among the most promiscuously translocated genes in hematological diseases. Among the 28 known fusion partners, there are two categories: homeobox genes and non-homeobox genes. The homeobox fusion partners are well-studied in animal models, resulting in HoxA cluster overexpression and hematological disease. The non-homeobox fusion partners are less well studied. We created transgenic animal models for three NUP98 fusion genes (one homeobox, two non-homeobox), and show that in this system, the NUP98-homeobox fusion promotes self-renewal and aberrant gene expression to a significantly greater extent. We conclude that homeobox partners create more potent NUP98 fusion oncogenes than do non-homeobox partners. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Interkingdom protein domain fusion: the case of an antimicrobial protein in potato (Solanum tuberosum)

    Czech Academy of Sciences Publication Activity Database

    Talianová, Martina; Vyskot, Boris; Janoušek, Bohuslav

    2011-01-01

    Roč. 297, 1-2 (2011), s. 129-139 ISSN 0378-2697 R&D Projects: GA ČR(CZ) GA521/08/0932; GA ČR(CZ) GD204/09/H002; GA MŠk(CZ) LC06004 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : horizontal gene transfer * interkingdom gene fusion * antimicrobial protein Subject RIV: BO - Biophysics Impact factor: 1.335, year: 2011

  1. Role of osteogenic protein-1/bone morphogenetic protein-7 in spinal fusion

    Directory of Open Access Journals (Sweden)

    Justin Munns

    2009-10-01

    Full Text Available Justin Munns, Daniel K Park, Kern SinghDepartment of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USAAbstract: Osteogenic protein-1 (OP-1, also known as bone morphogenetic protein-7 (BMP-7, is a protein in the TGF-β family of cellular proteins that has shown potential for application in patients undergoing spinal fusion due to its proven osteoinductive effects, particularly in patients with spondylolisthesis. OP-1 initiates numerous processes at the cellular level, acting on mesenchymal stem cells (MSCs, osteoblasts, and osteoclasts to stimulate bone growth. Animal studies of OP-1 have provided strong evidence for the ability of OP-1 to initiate ossification in posterolateral arthrodesis. Promising findings in early clinical trials with OP-1 prompted FDA approval for use in long bone nonunions in 2001 and subsequently for revision posterolateral arthrodesis in 2004 under a conditional Humanitarian Device Exemption. Larger clinical trials have recently shown no notable safety concerns or increases in adverse events associated with OP-1. However, a recent clinical trial has not conclusively demonstrated the noninferiority of OP-1 compared to autograft in revision posterolateral arthrodesis. The future of OP-1 application in patients with spondylolisthesis thus remains uncertain with the recent rejection of Premarket Approval (PMA status by the FDA (April 2009. Further investigation of its treatment success and immunological consequences appears warranted to establish FDA approval for its use in its current form.Keywords: osteogenic protein-1, bone morphogenetic protein-7, spinal fusion

  2. Cell fusion assay by expression of respiratory syncytial virus (RSV) fusion protein to analyze the mutation of palivizumab-resistant strains.

    Science.gov (United States)

    Yasui, Yosuke; Yamaji, Yoshiaki; Sawada, Akihito; Ito, Takashi; Nakayama, Tetsuo

    2016-05-01

    Respiratory syncytial virus (RSV) consists of fusion (F), glyco (G), and small hydrophobic (SH) proteins as envelope proteins, and infects through cell fusion. F protein is expressed on the surface of infected cells, and induces cell fusion. In the present report, expression plasmids of the F, G and SH proteins were constructed and cell fusion activity was investigated under T7 RNA polymerase. F protein alone induced cell fusion at a lower concentration than previously reported, and co-expression of F and SH proteins induced cell fusion more efficiently than F protein alone. Palivizumab is the only prophylactic agent against RSV infection. Palivizumab-resistant strains having mutations of the F protein of K272E and S275F were reported. These mutations were introduced into an F-expression plasmid, and exhibited no inhibition of cell fusion with palivizumab. Among the RSV F protein mutants, N276S has been reported to have partial resistance against palivizumab, but the F expression plasmid with the N276S mutation showed a reduction in cell fusion in the presence of palivizumab, showing no resistance to palivizumab. The present expression system was useful for investigating the mechanisms of RSV cell fusion. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. The Heptad Repeat C Domain of the Respiratory Syncytial Virus Fusion Protein Plays a Key Role in Membrane Fusion.

    Science.gov (United States)

    Bermingham, Imogen M; Chappell, Keith J; Watterson, Daniel; Young, Paul R

    2018-02-15

    Respiratory syncytial virus (RSV) mediates host cell entry through the fusion (F) protein, which undergoes a conformational change to facilitate the merger of viral and host lipid membrane envelopes. The RSV F protein comprises a trimer of disulfide-bonded F 1 and F 2 subunits that is present on the virion surface in a metastable prefusion state. This prefusion form is readily triggered to undergo refolding to bring two heptad repeats (heptad repeat A [HRA] and HRB) into close proximity to form a six-helix bundle that stabilizes the postfusion form and provides the free energy required for membrane fusion. This process can be triggered independently of other proteins. Here, we have performed a comprehensive analysis of a third heptad repeat region, HRC (amino acids 75 to 97), an amphipathic α-helix that lies at the interface of the prefusion F trimer and is a major structural feature of the F 2 subunit. We performed alanine scanning mutagenesis from Lys-75 to Met-97 and assessed all mutations in transient cell culture for expression, proteolytic processing, cell surface localization, protein conformation, and membrane fusion. Functional characterization revealed a striking distribution of activity in which fusion-increasing mutations localized to one side of the helical face, while fusion-decreasing mutations clustered on the opposing face. Here, we propose a model in which HRC plays a stabilizing role within the globular head for the prefusion F trimer and is potentially involved in the early events of triggering, prompting fusion peptide release and transition into the postfusion state. IMPORTANCE RSV is recognized as the most important viral pathogen among pediatric populations worldwide, yet no vaccine or widely available therapeutic treatment is available. The F protein is critical for the viral replication process and is the major target for neutralizing antibodies. Recent years have seen the development of prefusion stabilized F protein-based approaches to

  4. ChiPPI: a novel method for mapping chimeric protein-protein interactions uncovers selection principles of protein fusion events in cancer.

    Science.gov (United States)

    Frenkel-Morgenstern, Milana; Gorohovski, Alessandro; Tagore, Somnath; Sekar, Vaishnovi; Vazquez, Miguel; Valencia, Alfonso

    2017-07-07

    Fusion proteins, comprising peptides deriving from the translation of two parental genes, are produced in cancer by chromosomal aberrations. The expressed fusion protein incorporates domains of both parental proteins. Using a methodology that treats discrete protein domains as binding sites for specific domains of interacting proteins, we have cataloged the protein interaction networks for 11 528 cancer fusions (ChiTaRS-3.1). Here, we present our novel method, chimeric protein-protein interactions (ChiPPI) that uses the domain-domain co-occurrence scores in order to identify preserved interactors of chimeric proteins. Mapping the influence of fusion proteins on cell metabolism and pathways reveals that ChiPPI networks often lose tumor suppressor proteins and gain oncoproteins. Furthermore, fusions often induce novel connections between non-interactors skewing interaction networks and signaling pathways. We compared fusion protein PPI networks in leukemia/lymphoma, sarcoma and solid tumors finding distinct enrichment patterns for each disease type. While certain pathways are enriched in all three diseases (Wnt, Notch and TGF β), there are distinct patterns for leukemia (EGFR signaling, DNA replication and CCKR signaling), for sarcoma (p53 pathway and CCKR signaling) and solid tumors (FGFR and EGFR signaling). Thus, the ChiPPI method represents a comprehensive tool for studying the anomaly of skewed cellular networks produced by fusion proteins in cancer. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  5. Membrane fusion triggers rapid degradation of two gamete-specific, fusion-essential proteins in a membrane block to polygamy in Chlamydomonas

    OpenAIRE

    Liu, Yanjie; Misamore, Michael J.; Snell, William J.

    2010-01-01

    The plasma membranes of gametes are specialized for fusion, yet, once fusion occurs, in many organisms the new zygote becomes incapable of further membrane fusion reactions. The molecular mechanisms that underlie this loss of fusion capacity (block to polygamy) remain unknown. During fertilization in the green alga Chlamydomonas, the plus gamete-specific membrane protein FUS1 is required for adhesion between the apically localized sites on the plasma membranes of plus and minus gametes that a...

  6. Revealing Surface Waters on an Antifreeze Protein by Fusion Protein Crystallography Combined with Molecular Dynamic Simulations.

    Science.gov (United States)

    Sun, Tianjun; Gauthier, Sherry Y; Campbell, Robert L; Davies, Peter L

    2015-10-08

    Antifreeze proteins (AFPs) adsorb to ice through an extensive, flat, relatively hydrophobic surface. It has been suggested that this ice-binding site (IBS) organizes surface waters into an ice-like clathrate arrangement that matches and fuses to the quasi-liquid layer on the ice surface. On cooling, these waters join the ice lattice and freeze the AFP to its ligand. Evidence for the generality of this binding mechanism is limited because AFPs tend to crystallize with their IBS as a preferred protein-protein contact surface, which displaces some bound waters. Type III AFP is a 7 kDa globular protein with an IBS made up two adjacent surfaces. In the crystal structure of the most active isoform (QAE1), the part of the IBS that docks to the primary prism plane of ice is partially exposed to solvent and has clathrate waters present that match this plane of ice. The adjacent IBS, which matches the pyramidal plane of ice, is involved in protein-protein crystal contacts with few surface waters. Here we have changed the protein-protein contacts in the ice-binding region by crystallizing a fusion of QAE1 to maltose-binding protein. In this 1.9 Å structure, the IBS that fits the pyramidal plane of ice is exposed to solvent. By combining crystallography data with MD simulations, the surface waters on both sides of the IBS were revealed and match well with the target ice planes. The waters on the pyramidal plane IBS were loosely constrained, which might explain why other isoforms of type III AFP that lack the prism plane IBS are less active than QAE1. The AFP fusion crystallization method can potentially be used to force the exposure to solvent of the IBS on other AFPs to reveal the locations of key surface waters.

  7. The Fusion Loops of the Initial Prefusion Conformation of Herpes Simplex Virus 1 Fusion Protein Point Toward the Membrane

    Directory of Open Access Journals (Sweden)

    Juan Fontana

    2017-08-01

    Full Text Available All enveloped viruses, including herpesviruses, must fuse their envelope with the host membrane to deliver their genomes into target cells, making this essential step subject to interference by antibodies and drugs. Viral fusion is mediated by a viral surface protein that transits from an initial prefusion conformation to a final postfusion conformation. Strikingly, the prefusion conformation of the herpesvirus fusion protein, gB, is poorly understood. Herpes simplex virus (HSV, a model system for herpesviruses, causes diseases ranging from mild skin lesions to serious encephalitis and neonatal infections. Using cryo-electron tomography and subtomogram averaging, we have characterized the structure of the prefusion conformation and fusion intermediates of HSV-1 gB. To this end, we have set up a system that generates microvesicles displaying full-length gB on their envelope. We confirmed proper folding of gB by nondenaturing electrophoresis-Western blotting with a panel of monoclonal antibodies (MAbs covering all gB domains. To elucidate the arrangement of gB domains, we labeled them by using (i mutagenesis to insert fluorescent proteins at specific positions, (ii coexpression of gB with Fabs for a neutralizing MAb with known binding sites, and (iii incubation of gB with an antibody directed against the fusion loops. Our results show that gB starts in a compact prefusion conformation with the fusion loops pointing toward the viral membrane and suggest, for the first time, a model for gB’s conformational rearrangements during fusion. These experiments further illustrate how neutralizing antibodies can interfere with the essential gB structural transitions that mediate viral entry and therefore infectivity.

  8. Peptide mimics of a conformationally constrained protective epitopes of respiratory syncytial virus fusion protein

    NARCIS (Netherlands)

    Chargelegue, D.; Obeid, O.E.; Shaw, D.M.; Denbury, A.N.; Hobby, P.; Hsu, S.C.; Steward, M.W.

    1997-01-01

    Aims: To identify peptides that mimic (mimotopes) conformational and protective epitopes of RSV fusion protein and to assess their efficacy as immunogens and potential vaccines. Material and methods: An 8-mer solid- phase (TG resin) library was screened with a neutralising and protective RSV fusion

  9. Gene transfer mediated by fusion protein hemagglutinin reconstituted in cationic lipid vesicles

    NARCIS (Netherlands)

    Schoen, P; Chonn, A; Cullis, PR; Wilschut, J; Scherrer, P

    Hemagglutinin, the membrane fusion protein of influenza virus,is known to mediate a low-pH-dependent fusion reaction between the viral envelope and the limiting membrane of the endosomal cell compartment following cellular uptake of the virus particles by receptor-mediated endocytosis. Here we

  10. Fusion

    Science.gov (United States)

    Herman, Robin

    1990-10-01

    The book abounds with fascinating anecdotes about fusion's rocky path: the spurious claim by Argentine dictator Juan Peron in 1951 that his country had built a working fusion reactor, the rush by the United States to drop secrecy and publicize its fusion work as a propaganda offensive after the Russian success with Sputnik; the fortune Penthouse magazine publisher Bob Guccione sank into an unconventional fusion device, the skepticism that met an assertion by two University of Utah chemists in 1989 that they had created "cold fusion" in a bottle. Aimed at a general audience, the book describes the scientific basis of controlled fusion--the fusing of atomic nuclei, under conditions hotter than the sun, to release energy. Using personal recollections of scientists involved, it traces the history of this little-known international race that began during the Cold War in secret laboratories in the United States, Great Britain and the Soviet Union, and evolved into an astonishingly open collaboration between East and West.

  11. Role of protein disulfide isomerase and other thiol-reactive proteins in HIV-1 envelope protein-mediated fusion

    International Nuclear Information System (INIS)

    Ou Wu; Silver, Jonathan

    2006-01-01

    Cell-surface protein disulfide isomerase (PDI) has been proposed to promote disulfide bond rearrangements in HIV-1 envelope protein (Env) that accompany Env-mediated fusion. We evaluated the role of PDI in ways that have not been previously tested by downregulating PDI with siRNA and by overexpressing wild-type or variant forms of PDI in transiently and stably transfected cells. These manipulations, as well as treatment with anti-PDI antibodies, had only small effects on infection or cell fusion mediated by NL4-3 or AD8 strains of HIV-1. However, the cell-surface thiol-reactive reagent 5, 5'-dithiobis(2-nitrobenzoic acid) (DTNB) had a much stronger inhibitory effect in our system, suggesting that cell-surface thiol-containing molecules other than PDI, acting alone or in concert, have a greater effect than PDI on HIV-1 Env-mediated fusion. We evaluated one such candidate, thioredoxin, a PDI family member reported to reduce a labile disulfide bond in CD4. We found that the ability of thioredoxin to reduce the disulfide bond in CD4 is enhanced in the presence of HIV-1 Env gp120 and that thioredoxin also reduces disulfide bonds in gp120 directly in the absence of CD4. We discuss the implications of these observations for identification of molecules involved in disulfide rearrangements in Env during fusion

  12. [Preparation and the biological effect of fusion protein GLP-1-exendin-4/ IgG4(Fc) fusion protein as long acting GLP-1 receptor agonist].

    Science.gov (United States)

    Zheng, Yun-cheng

    2015-12-01

    GLP-1 has a variety of anti-diabetic effects. However, native GLP-1 is not suitable for treatment of diabetes due to its short half-life (t½, 2-5 min). Exendin-4 is a polypeptide isolated from lizard saliva, which can bind to GLP-1 receptor, produce physiological effects similar to GLP-1, t½ up to 2.5 h, therefore, we developed a long-lasting GLP-1 receptor agonists and GLP-1-exendin-4 fusion IgG4 Fc [GLP-1-exendin-4/ IgG4(Fc)]. We constructed the eukaryotic expression vector of human GLP-1-exendin-4/IgG4(Fc)-pOptiVEC- TOPO by gene recombination technique and expressed the fusion protein human GLP-1-IgG4 (Fc) in CHO/DG44 cells. The fusion protein stimulated the INS-1 cells secretion of insulin, GLP-1, exendin-4 and fusion protein in CD1 mice pharmacokinetic experiments, as well as GLP-1, exendin-4 and fusion protein did anti-diabetic effect on streptozotocin induced mice. Results demonstrated that the GLP-1-exendin-4/IgG4(Fc) positive CHO/DG44 clones were chosen and the media from these positive clones. Western blotting showed that one protein band was found to match well with the predicted relative molecular mass of human GLP-1-exendin-4/IgG4(Fc). Insulin RIA showed that GLP-1-exendin-4/IgG4(Fc) dose-dependently stimulated insulin secretion from INS-1 cells. Pharmacokinetic studies in CD1 mice showed that with intraperitoneal injection (ip), the fusion protein peaked at 30 min in circulation and maintained a plateau for 200 h. Natural biological half-life of exendin-4 was (1.39 ± 0.28) h, GLP-1 in vivo t½ 4 min, indicating that fusion protein has long-lasting effects on the modulation of glucose homeostasis. GLP-1-exendin-4/IgG4(Fc) was found to be effective in reducing the incidence of diabetes in multiple-low-dose streptozotocin-induced diabetes in mice, longer duration of the biological activity of the fusion protein. The biological activity was significantly higher than that of GLP-1 and exendin-4. GLP-1-exendin-4/IgG4(Fc) has good anti-diabetic activity

  13. Expression of polyhedrin-hEGF fusion protein in cultured cells and ...

    African Journals Online (AJOL)

    GRACE

    2006-06-02

    , protease K, X-gal and related reagents were purchased from Roche ..... fusion protein in silkworm larvae infected with recombinant Bombyx mori nuclear polyhedrosis virus. J. Gen. Virol. 68: 2599-2606. Massotte D (2003).

  14. Antibody-Cytokine Fusion Proteins for the Therapy of Breast Cancer

    National Research Council Canada - National Science Library

    Morrision, Sherie

    2002-01-01

    .... Expression of these cytokines by cancer cells has been shown to render them immunogenic. The anti- HER2/neu antibody fusion proteins were intended to localize the cytokine at the tumor where it is expected to elicit an immune response...

  15. Antibody-Cytokine Fusion Proteins for the Therapy of Breast Cancer

    National Research Council Canada - National Science Library

    Morrison, Sherri

    2000-01-01

    We have proposed to develop novel antibody fusion proteins in which antibodies specific for the breast cancer tumor associated antigen HER2/neu will be genetically fused to the cytokines IL-2, IL-12, and GM-CSF...

  16. Fusion tags for protein solubility, purification and immunogenicity in Escherichia coli: the novel Fh8 system.

    Science.gov (United States)

    Costa, Sofia; Almeida, André; Castro, António; Domingues, Lucília

    2014-01-01

    Proteins are now widely produced in diverse microbial cell factories. The Escherichia coli is still the dominant host for recombinant protein production but, as a bacterial cell, it also has its issues: the aggregation of foreign proteins into insoluble inclusion bodies is perhaps the main limiting factor of the E. coli expression system. Conversely, E. coli benefits of cost, ease of use and scale make it essential to design new approaches directed for improved recombinant protein production in this host cell. With the aid of genetic and protein engineering novel tailored-made strategies can be designed to suit user or process requirements. Gene fusion technology has been widely used for the improvement of soluble protein production and/or purification in E. coli, and for increasing peptide's immunogenicity as well. New fusion partners are constantly emerging and complementing the traditional solutions, as for instance, the Fh8 fusion tag that has been recently studied and ranked among the best solubility enhancer partners. In this review, we provide an overview of current strategies to improve recombinant protein production in E. coli, including the key factors for successful protein production, highlighting soluble protein production, and a comprehensive summary of the latest available and traditionally used gene fusion technologies. A special emphasis is given to the recently discovered Fh8 fusion system that can be used for soluble protein production, purification, and immunogenicity in E. coli. The number of existing fusion tags will probably increase in the next few years, and efforts should be taken to better understand how fusion tags act in E. coli. This knowledge will undoubtedly drive the development of new tailored-made tools for protein production in this bacterial system.

  17. Fusion tags for protein solubility, purification and immunogenicity in Escherichia coli: the novel Fh8 system

    Science.gov (United States)

    Costa, Sofia; Almeida, André; Castro, António; Domingues, Lucília

    2014-01-01

    Proteins are now widely produced in diverse microbial cell factories. The Escherichia coli is still the dominant host for recombinant protein production but, as a bacterial cell, it also has its issues: the aggregation of foreign proteins into insoluble inclusion bodies is perhaps the main limiting factor of the E. coli expression system. Conversely, E. coli benefits of cost, ease of use and scale make it essential to design new approaches directed for improved recombinant protein production in this host cell. With the aid of genetic and protein engineering novel tailored-made strategies can be designed to suit user or process requirements. Gene fusion technology has been widely used for the improvement of soluble protein production and/or purification in E. coli, and for increasing peptide’s immunogenicity as well. New fusion partners are constantly emerging and complementing the traditional solutions, as for instance, the Fh8 fusion tag that has been recently studied and ranked among the best solubility enhancer partners. In this review, we provide an overview of current strategies to improve recombinant protein production in E. coli, including the key factors for successful protein production, highlighting soluble protein production, and a comprehensive summary of the latest available and traditionally used gene fusion technologies. A special emphasis is given to the recently discovered Fh8 fusion system that can be used for soluble protein production, purification, and immunogenicity in E. coli. The number of existing fusion tags will probably increase in the next few years, and efforts should be taken to better understand how fusion tags act in E. coli. This knowledge will undoubtedly drive the development of new tailored-made tools for protein production in this bacterial system. PMID:24600443

  18. Bacteriophage membrane protein P9 as a fusion partner for the efficient expression of membrane proteins in Escherichia coli.

    Science.gov (United States)

    Jung, Yuna; Jung, Hyeim; Lim, Dongbin

    2015-12-01

    Despite their important roles and economic values, studies of membrane proteins have been hampered by the difficulties associated with obtaining sufficient amounts of protein. Here, we report a novel membrane protein expression system that uses the major envelope protein (P9) of phage φ6 as an N-terminal fusion partner. Phage membrane protein P9 facilitated the synthesis of target proteins and their integration into the Escherichia coli cell membrane. This system was used to produce various multi-pass transmembrane proteins, including G-protein-coupled receptors, transporters, and ion channels of human origin. Green fluorescent protein fusion was used to confirm the correct folding of the expressed proteins. Of the 14 membrane proteins tested, eight were highly expressed, three were moderately expressed, and three were barely expressed in E. coli. Seven of the eight highly expressed proteins could be purified after extraction with the mild detergent lauryldimethylamine-oxide. Although a few proteins have previously been developed as fusion partners to augment membrane protein production, we believe that the major envelope protein P9 described here is better suited to the efficient expression of eukaryotic transmembrane proteins in E. coli. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. A novel Ffu fusion system for secretory expression of heterologous proteins in Escherichia coli.

    Science.gov (United States)

    Cheng, Cheng; Wu, Shanshan; Cui, Lupeng; Wu, Yulu; Jiang, Tianyue; He, Bingfang

    2017-12-21

    The high level of excretion and rapid folding ability of β-fructofuranosidase (β-FFase) in Escherichia coli has suggested that β-FFase from Arthrobacter arilaitensis NJEM01 can be developed as a fusion partner. Based on the modified Wilkinson and Harrison algorithm and the preliminary verification of the solubility-enhancing ability of β-FFase truncations, three β-FFase truncations (i.e., Ffu209, Ffu217, and Ffu312) with a native signal peptide were selected as novel Ffu fusion tags. Four difficult-to-express protein models; i.e., CARDS TX, VEGFR-2, RVs and Omp85 were used in the assessment of Ffu fusion tags. The expression levels and solubility of each protein were markedly enhanced by the Ffu fusion system. Each protein had a favorable Ffu tag. The Ffu fusion tags performed preferably when compared with the well-known fusion tags MBP and NusA. Strikingly, it was confirmed that Ffu fusion proteins were secreted into the periplasm by the periplasmic analysis and N-amino acid sequence analysis. Further, efficient excretion of HV3 with defined anti-thrombin activity was obtained when it was fused with the Ffu312 tag. Moreover, HV3 remained soluble and demonstrated notable anti-thrombin activity after the removal of the Ffu312 tag by enterokinase. Observations from this work not only complements fusion technologies, but also develops a novel and effective secretory system to solve key issues that include inclusion bodies and degradation when expressing heterologous proteins in E. coli, especially for proteins that require disulfide bond formation, eukaryotic-secreted proteins, and membrane-associated proteins.

  20. Recombinant production of a peroxidase-protein G fusion protein in Pichia pastoris.

    Science.gov (United States)

    Krainer, Florian Wolfgang; Darnhofer, Barbara; Birner-Gruenberger, Ruth; Glieder, Anton

    2016-02-10

    Streptococcal protein G (SpG) binds immunoglobulin G from a broad range of mammalian species with high affinity. Chemical conjugations of SpG to the reporter enzyme horseradish peroxidase (HRP) are commonly used in immunohistochemical applications. However, commercial HRP preparations are typically isolated from horseradish roots as varying mixtures of HRP isoenzymes with different biochemical properties, and chemical conjugation procedures lead to heterogeneous HRP-SpG preparations, partially including inactivated enzyme. A recombinant process allows the production of a well-defined HRP isoenzyme fused to SpG at constant 1:1 stoichiometry in a single step without the need for laborious chemical conjugation. By using state-of-the-art biotechnological tools, we produced a recombinant HRP-SpG fusion protein in Pichia pastoris in bioreactor cultivations. Purified HRP-SpG was tested successfully for functional binding of antibodies from different mammalian serums. Recombinant production of this novel well-defined fusion protein follows quality-by-design principles and facilitates the production of more reliable and cost-effective diagnostic kits. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Deltabaculoviruses encode a functional type I budded virus envelope fusion protein

    Science.gov (United States)

    Envelope fusion proteins (F proteins) are major constituents of budded viruses (BVs) of alpha- and betabaculoviruses (Baculoviridae) and are essential for the systemic infection of insect larvae and insect cells in culture. An F protein homolog gene was absent in gammabaculoviruses. Here we show tha...

  2. An insight into fusion technology aiding efficient recombinant protein production for functional proteomics.

    Science.gov (United States)

    Yadav, Dinesh K; Yadav, Neelam; Yadav, Sarika; Haque, Shafiul; Tuteja, Narendra

    2016-12-15

    Advancements in peptide fusion technologies to maximize the protein production has taken a big leap to fulfill the demands of post-genomics era targeting elucidation of structure/function of the proteome and its therapeutic applications, by over-expression in heterologous expression systems. Despite being most preferred protein expression system armed with variety of cardinal fusion tags, expression of the functionally active recombinant protein in E. coli remains plagued. The present review critically analyses the aptness of well-characterized fusion tags utilized for over-expression of recombinant proteins with improved solubility and their compatibility with downstream purification procedures. The combinatorial tandem affinity strategies have shown to provide more versatile options. Solubility decreasing fusion tags have proved to facilitate the overproduction of antimicrobial peptides. Efficient removal of fusion tags prior to final usage is of utmost importance and has been summarized discussing the efficiency of various enzymatic and chemical methods of tag removal. Unfortunately, no single fusion tag works as a magic bullet to completely fulfill the requirements of protein expression and purification in active form. The information provided might help in selection and development of a successful protocol for efficient recombinant protein production for functional proteomics. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. The TIP30 protein complex, arachidonic acid and coenzyme A are required for vesicle membrane fusion.

    Directory of Open Access Journals (Sweden)

    Chengliang Zhang

    Full Text Available Efficient membrane fusion has been successfully mimicked in vitro using artificial membranes and a number of cellular proteins that are currently known to participate in membrane fusion. However, these proteins are not sufficient to promote efficient fusion between biological membranes, indicating that critical fusogenic factors remain unidentified. We have recently identified a TIP30 protein complex containing TIP30, acyl-CoA synthetase long-chain family member 4 (ACSL4 and Endophilin B1 (Endo B1 that promotes the fusion of endocytic vesicles with Rab5a vesicles, which transport endosomal acidification enzymes vacuolar (H⁺-ATPases (V-ATPases to the early endosomes in vivo. Here, we demonstrate that the TIP30 protein complex facilitates the fusion of endocytic vesicles with Rab5a vesicles in vitro. Fusion of the two vesicles also depends on arachidonic acid, coenzyme A and the synthesis of arachidonyl-CoA by ACSL4. Moreover, the TIP30 complex is able to transfer arachidonyl groups onto phosphatidic acid (PA, producing a new lipid species that is capable of inducing close contact between membranes. Together, our data suggest that the TIP30 complex facilitates biological membrane fusion through modification of PA on membranes.

  4. Polyclonal and monoclonal antibodies specific for the six-helix bundle of the human respiratory syncytial virus fusion glycoprotein as probes of the protein post-fusion conformation

    International Nuclear Information System (INIS)

    Palomo, Concepción; Mas, Vicente; Vázquez, Mónica; Cano, Olga; Luque, Daniel; Terrón, María C.; Calder, Lesley J.; Melero, José A.

    2014-01-01

    Human respiratory syncytial virus (hRSV) has two major surface glycoproteins (G and F) anchored in the lipid envelope. Membrane fusion promoted by hRSV F occurs via refolding from a pre-fusion form to a highly stable post-fusion state involving large conformational changes of the F trimer. One of these changes results in assembly of two heptad repeat sequences (HRA and HRB) into a six-helix bundle (6HB) motif. To assist in distinguishing pre- and post-fusion conformations of hRSV F , we have prepared polyclonal (α-6HB) and monoclonal (R145) rabbit antibodies specific for the 6HB. Among other applications, these antibodies were used to explore the requirements of 6HB formation by isolated protein segments or peptides and by truncated mutants of the F protein. Site-directed mutagenesis and electron microscopy located the R145 epitope in the post-fusion hRSV F at a site distantly located from previously mapped epitopes, extending the repertoire of antibodies that can decorate the F molecule. - Highlights: • Antibodies specific for post-fusion respiratory syncytial virus fusion protein are described. • Polyclonal antibodies were obtained in rabbit inoculated with chimeric heptad repeats. • Antibody binding required assembly of a six-helix bundle in the post-fusion protein. • A monoclonal antibody with similar structural requirements is also described. • Binding of this antibody to the post-fusion protein was visualized by electron microscopy

  5. Polyclonal and monoclonal antibodies specific for the six-helix bundle of the human respiratory syncytial virus fusion glycoprotein as probes of the protein post-fusion conformation

    Energy Technology Data Exchange (ETDEWEB)

    Palomo, Concepción; Mas, Vicente; Vázquez, Mónica; Cano, Olga [Unidad de Biología Viral, Centro Nacional de Microbiología, Madrid (Spain); CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid (Spain); Luque, Daniel; Terrón, María C. [Unidad de Microscopía Electrónica y Confocal, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid (Spain); Calder, Lesley J. [National Institute for Medical Research, MRC, Mill Hill, London NW7 1AA (United Kingdom); Melero, José A., E-mail: jmelero@isciii.es [Unidad de Biología Viral, Centro Nacional de Microbiología, Madrid (Spain); CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid (Spain)

    2014-07-15

    Human respiratory syncytial virus (hRSV) has two major surface glycoproteins (G and F) anchored in the lipid envelope. Membrane fusion promoted by hRSV{sub F} occurs via refolding from a pre-fusion form to a highly stable post-fusion state involving large conformational changes of the F trimer. One of these changes results in assembly of two heptad repeat sequences (HRA and HRB) into a six-helix bundle (6HB) motif. To assist in distinguishing pre- and post-fusion conformations of hRSV{sub F}, we have prepared polyclonal (α-6HB) and monoclonal (R145) rabbit antibodies specific for the 6HB. Among other applications, these antibodies were used to explore the requirements of 6HB formation by isolated protein segments or peptides and by truncated mutants of the F protein. Site-directed mutagenesis and electron microscopy located the R145 epitope in the post-fusion hRSV{sub F} at a site distantly located from previously mapped epitopes, extending the repertoire of antibodies that can decorate the F molecule. - Highlights: • Antibodies specific for post-fusion respiratory syncytial virus fusion protein are described. • Polyclonal antibodies were obtained in rabbit inoculated with chimeric heptad repeats. • Antibody binding required assembly of a six-helix bundle in the post-fusion protein. • A monoclonal antibody with similar structural requirements is also described. • Binding of this antibody to the post-fusion protein was visualized by electron microscopy.

  6. A novel fusion partner for enhanced secretion of recombinant proteins in Saccharomyces cerevisiae.

    Science.gov (United States)

    Bae, Jung-Hoon; Sung, Bong Hyun; Seo, Jeong-Woo; Kim, Chul Ho; Sohn, Jung-Hoon

    2016-12-01

    Expressing proteins with fusion partners improves yield and simplifies the purification process. We developed a novel fusion partner to improve the secretion of heterologous proteins that are otherwise poorly excreted in yeast. The VOA1 (YGR106C) gene of Saccharomyces cerevisiae encodes a subunit of vacuolar ATPase. We found that C-terminally truncated Voa1p was highly secreted into the culture medium, even when fused with rarely secreted heterologous proteins such as human interleukin-2 (hIL-2). Deletion mapping of C-terminally truncated Voa1p, identified a hydrophilic 28-amino acid peptide (HL peptide) that was responsible for the enhanced secretion of target protein. A purification tag and a protease cleavage site were added to use HL peptide as a multi-purpose fusion partner. The utility of this system was tested via the expression and purification of various heterologous proteins. In many cases, the yield of target proteins fused with the peptide was significantly increased, and fusion proteins could be directly purified with affinity chromatography. The fusion partner was removed by in vitro processing, and intact proteins were purified by re-application of samples to affinity chromatography.

  7. Effect of Tumor Necrosis Factor-α on Neutralization of Ventricular Fibrillation in Rats with Acute Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Yu Chen

    2011-01-01

    Full Text Available The purpose of this study was to explore the effects of tumor necrosis factor-α (TNF-α on ventricular fibrillation (VF in rats with acute myocardial infarction (AMI. Rats were randomly classified into AMI group, sham operation group and recombinant human tumor necrosis factor receptor:Fc fusion protein (rhTNFR:Fc group. Spontaneous and induced VFs were recorded. Monophasic action potentials (MAPs among different zones of myocardium were recorded at eight time points before and after ligation and MAP duration dispersions (MAPDds were calculated. Then expression of TNF-α among different myocardial zones was detected. After ligation of the left anterior descending coronary artery, total TNF-α expression in AMI group began to markedly increase at 10 min, reached a climax at 20–30min, and then gradually decreased. The time-windows of VFs and MAPDds in the border zone performed in a similar way. At the same time-point, the expression of TNF-α in the ischemia zone was greater than that in the border zone, and little in the non-ischemia zone. Although the time windows of TNF-α expression, the MAPDds in the border zone and the occurrence of VFs in the rhTNFR:Fc group were similar to those in the AMI group, they all decreased in the rhTNFR:Fc group. Our findings demonstrate that TNF-α could enlarge the MAPDds in the border zone, and promote the onset of VFs.

  8. Escherichia coli fusion carrier proteins act as solubilizing agents for recombinant uncoupling protein 1 through interactions with GroEL

    International Nuclear Information System (INIS)

    Douette, Pierre; Navet, Rachel; Gerkens, Pascal; Galleni, Moreno; Levy, Daniel; Sluse, Francis E.

    2005-01-01

    Fusing recombinant proteins to highly soluble partners is frequently used to prevent aggregation of recombinant proteins in Escherichia coli. Moreover, co-overexpression of prokaryotic chaperones can increase the amount of properly folded recombinant proteins. To understand the solubility enhancement of fusion proteins, we designed two recombinant proteins composed of uncoupling protein 1 (UCP1), a mitochondrial membrane protein, in fusion with MBP or NusA. We were able to express soluble forms of MBP-UCP1 and NusA-UCP1 despite the high hydrophobicity of UCP1. Furthermore, the yield of soluble fusion proteins depended on co-overexpression of GroEL that catalyzes folding of polypeptides. MBP-UCP1 was expressed in the form of a non-covalent complex with GroEL. MBP-UCP1/GroEL was purified and characterized by dynamic light scattering, gel filtration, and electron microscopy. Our findings suggest that MBP and NusA act as solubilizing agents by forcing the recombinant protein to pass through the bacterial chaperone pathway in the context of fusion protein

  9. Enhanced expression of rabies virus surface G-protein in Escherichia coli using SUMO fusion.

    Science.gov (United States)

    Singh, Ankit; Yadav, Dinesh; Rai, Krishan Mohan; Srivastava, Meenal; Verma, Praveen C; Singh, Pradhyumna K; Tuli, Rakesh

    2012-01-01

    Fusion systems are known to increase the expression of difficult to express recombinant proteins in soluble form to facilitate their purification. Rabies glycoprotein was also tough to express at sufficient level in soluble form in both E. coli and plant. The present work was aimed to over-express and purify this membrane protein from soluble extract of E. coli. Fusion of Small Ubiqutin like Modifier (SUMO) with rabies glycoprotein increased ~1.5 fold higher expression and ~3.0 fold solubility in comparison to non-fused in E. coli. The SUMO fusion also simplified the purification process. Previously engineered rabies glycoprotein gene in tobacco plants provides complete protection to mice, but the expression was very low for purification. Our finding demonstrated that the SUMO-fusion was useful for enhancing expression and solubility of the membrane protein and again proves to be a good alternative technology for applications in biomedical and pharmaceutical research.

  10. The novel Fh8 and H fusion partners for soluble protein expression in Escherichia coli: a comparison with the traditional gene fusion technology.

    Science.gov (United States)

    Costa, Sofia J; Almeida, André; Castro, António; Domingues, Lucília; Besir, Hüseyin

    2013-08-01

    The Escherichia coli host system is an advantageous choice for simple and inexpensive recombinant protein production but it still presents bottlenecks at expressing soluble proteins from other organisms. Several efforts have been taken to overcome E. coli limitations, including the use of fusion partners that improve protein expression and solubility. New fusion technologies are emerging to complement the traditional solutions. This work evaluates two novel fusion partners, the Fh8 tag (8 kDa) and the H tag (1 kDa), as solubility enhancing tags in E. coli and their comparison to commonly used fusion partners. A broad range comparison was conducted in a small-scale screening and subsequently scaled-up. Six difficult-to-express target proteins (RVS167, SPO14, YPK1, YPK2, Frutalin and CP12) were fused to eight fusion tags (His, Trx, GST, MBP, NusA, SUMO, H and Fh8). The resulting protein expression and solubility levels were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis before and after protein purification and after tag removal. The Fh8 partner improved protein expression and solubility as the well-known Trx, NusA or MBP fusion partners. The H partner did not function as a solubility tag. Cleaved proteins from Fh8 fusions were soluble and obtained in similar or higher amounts than proteins from the cleavage of other partners as Trx, NusA or MBP. The Fh8 fusion tag therefore acts as an effective solubility enhancer, and its low molecular weight potentially gives it an advantage over larger solubility tags by offering a more reliable assessment of the target protein solubility when expressed as a fusion protein.

  11. Green fluorescence protein-based content-mixing assay of SNARE-driven membrane fusion.

    Science.gov (United States)

    Heo, Paul; Kong, Byoungjae; Jung, Young-Hun; Park, Joon-Bum; Shin, Jonghyeok; Park, Myungseo; Kweon, Dae-Hyuk

    2017-06-17

    Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins mediate intracellular membrane fusion by forming a ternary SNARE complex. A minimalist approach utilizing proteoliposomes with reconstituted SNARE proteins yielded a wealth of information pinpointing the molecular mechanism of SNARE-mediated fusion and its regulation by accessory proteins. Two important attributes of a membrane fusion are lipid-mixing and the formation of an aqueous passage between apposing membranes. These two attributes are typically observed by using various fluorescent dyes. Currently available in vitro assay systems for observing fusion pore opening have several weaknesses such as cargo-bleeding, incomplete removal of unencapsulated dyes, and inadequate information regarding the size of the fusion pore, limiting measurements of the final stage of membrane fusion. In the present study, we used a biotinylated green fluorescence protein and streptavidin conjugated with Dylight 594 (DyStrp) as a Föster resonance energy transfer (FRET) donor and acceptor, respectively. This FRET pair encapsulated in each v-vesicle containing synaptobrevin and t-vesicle containing a binary acceptor complex of syntaxin 1a and synaptosomal-associated protein 25 revealed the opening of a large fusion pore of more than 5 nm, without the unwanted signals from unencapsulated dyes or leakage. This system enabled determination of the stoichiometry of the merging vesicles because the FRET efficiency of the FRET pair depended on the molar ratio between dyes. Here, we report a robust and informative assay for SNARE-mediated fusion pore opening. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Construction,expression,purification and identification of prokaryotic expression vector of MART-1 fusion protein

    Directory of Open Access Journals (Sweden)

    Zhao-ting MENG

    2011-09-01

    Full Text Available Objective To construct a prokaryotic expression plasmid containing a fusion gene of MART-1 expressing the His-MART-1 fusion protein in E.coli,and to purify the protein and identify the immunogenicity of His-MART-1.Methods The MART-1 coding sequence was amplified by polymerase chain reaction(PCR,and then cloned into the prokaryotic expression vector(pET-28b containing His tag.The constructed vector,verified by restriction endonuclease digestion,PCR and DNA sequencing,was then transformed into E.coli for expression.The expression of MART-1 recombinant protein was induced by IPTG in E.coli,purified with Ni2+-NTA affinity chromatography method,and identified by SDS-PAGE and Western blotting.ELISA was used to detect the IFN-γ expression secreted by the His-MART-1 specific CD4+ T cells which recognized the His-MART-1 fusion protein presented by dendritic cells(DCs.Results The successful construction of recombinant plasmid was confirmed by restriction digestion,PCR and sequencing.The molecular weight of the purified fusion protein was identified as 13kD by SDS-PAGE,which was identical to the expected value.It was confirmed by western blotting that His-MART-1 fusion protein could be recognized by His monoclonal antibody.ELISA analysis showed that His-MART-1 fusion protein presented by DCs could induce IFN-γ secretion of MART-1 specific CD4+ T cells.Conclusion The recombinant plasmid of pET-28b-MART-1 has been successfully constructed.The expressed His-MART-1 fusion protein has been purified and the immunogenicity of inducing responses between DCs and CD4+ T cells has been determined.

  13. Expression of Leukemia-Associated Nup98 Fusion Proteins Generates an Aberrant Nuclear Envelope Phenotype.

    Science.gov (United States)

    Fahrenkrog, Birthe; Martinelli, Valérie; Nilles, Nadine; Fruhmann, Gernot; Chatel, Guillaume; Juge, Sabine; Sauder, Ursula; Di Giacomo, Danika; Mecucci, Cristina; Schwaller, Jürg

    2016-01-01

    Chromosomal translocations involving the nucleoporin NUP98 have been described in several hematopoietic malignancies, in particular acute myeloid leukemia (AML). In the resulting chimeric proteins, Nup98's N-terminal region is fused to the C-terminal region of about 30 different partners, including homeodomain (HD) transcription factors. While transcriptional targets of distinct Nup98 chimeras related to immortalization are relatively well described, little is known about other potential cellular effects of these fusion proteins. By comparing the sub-nuclear localization of a large number of Nup98 fusions with HD and non-HD partners throughout the cell cycle we found that while all Nup98 chimeras were nuclear during interphase, only Nup98-HD fusion proteins exhibited a characteristic speckled appearance. During mitosis, only Nup98-HD fusions were concentrated on chromosomes. Despite the difference in localization, all tested Nup98 chimera provoked morphological alterations in the nuclear envelope (NE), in particular affecting the nuclear lamina and the lamina-associated polypeptide 2α (LAP2α). Importantly, such aberrations were not only observed in transiently transfected HeLa cells but also in mouse bone marrow cells immortalized by Nup98 fusions and in cells derived from leukemia patients harboring Nup98 fusions. Our findings unravel Nup98 fusion-associated NE alterations that may contribute to leukemogenesis.

  14. Expression of Leukemia-Associated Nup98 Fusion Proteins Generates an Aberrant Nuclear Envelope Phenotype.

    Directory of Open Access Journals (Sweden)

    Birthe Fahrenkrog

    Full Text Available Chromosomal translocations involving the nucleoporin NUP98 have been described in several hematopoietic malignancies, in particular acute myeloid leukemia (AML. In the resulting chimeric proteins, Nup98's N-terminal region is fused to the C-terminal region of about 30 different partners, including homeodomain (HD transcription factors. While transcriptional targets of distinct Nup98 chimeras related to immortalization are relatively well described, little is known about other potential cellular effects of these fusion proteins. By comparing the sub-nuclear localization of a large number of Nup98 fusions with HD and non-HD partners throughout the cell cycle we found that while all Nup98 chimeras were nuclear during interphase, only Nup98-HD fusion proteins exhibited a characteristic speckled appearance. During mitosis, only Nup98-HD fusions were concentrated on chromosomes. Despite the difference in localization, all tested Nup98 chimera provoked morphological alterations in the nuclear envelope (NE, in particular affecting the nuclear lamina and the lamina-associated polypeptide 2α (LAP2α. Importantly, such aberrations were not only observed in transiently transfected HeLa cells but also in mouse bone marrow cells immortalized by Nup98 fusions and in cells derived from leukemia patients harboring Nup98 fusions. Our findings unravel Nup98 fusion-associated NE alterations that may contribute to leukemogenesis.

  15. Design and construction of self-assembling supramolecular protein complexes using artificial and fusion proteins as nanoscale building blocks.

    Science.gov (United States)

    Kobayashi, Naoya; Arai, Ryoichi

    2017-08-01

    The central goal of nanobiotechnology is to design and construct novel biomaterials of nanometer sizes. In this short review, we describe recent progress of several approaches for designing and creating artificial self-assembling protein complexes and primarily focus on the following biotechnological strategies for using artificial and fusion proteins as nanoscale building blocks: fusion proteins designed for symmetrical self-assembly; three-dimensional domain-swapped oligomers; self-assembling designed coiled-coil peptide modules; metal-directed self-assembling engineered proteins; computationally designed self-assembling de novo proteins; and self-assembling protein nanobuilding blocks (PN-Blocks) using an intermolecularly folded dimeric de novo protein. These state-of-the-art nanobiotechnologies for designing supramolecular protein complexes will facilitate the development of novel functional nanobiomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Connecting two proteins using a fusion alpha helix stabilized by a chemical cross linker

    Science.gov (United States)

    Jeong, Woo Hyeon; Lee, Haerim; Song, Dong Hyun; Eom, Jae-Hoon; Kim, Sun Chang; Lee, Hee-Seung; Lee, Hayyoung; Lee, Jie-Oh

    2016-03-01

    Building a sophisticated protein nano-assembly requires a method for linking protein components in a predictable and stable structure. Most of the cross linkers available have flexible spacers. Because of this, the linked hybrids have significant structural flexibility and the relative structure between their two components is largely unpredictable. Here we describe a method of connecting two proteins via a `fusion α helix' formed by joining two pre-existing helices into a single extended helix. Because simple ligation of two helices does not guarantee the formation of a continuous helix, we used EY-CBS, a synthetic cross linker that has been shown to react selectively with cysteines in α-helices, to stabilize the connecting helix. Formation and stabilization of the fusion helix was confirmed by determining the crystal structures of the fusion proteins with and without bound EY-CBS. Our method should be widely applicable for linking protein building blocks to generate predictable structures.

  17. Subcloning of HIV-2 nef genes in E. coli and immunological reactivity of expressed fusion proteins.

    Science.gov (United States)

    Ulrich, R; Siakkou, H; Mayer, J; Kienzle, N; Müller-Lantzsch, N; Krüger, D H

    1993-09-01

    The nef gene located in the 3' region of the HIV-2 genome encodes an N-terminally myristylated protein of 27-35 kD, likely to be involved in the regulation of viral transcription. The nef genes of HIV-2 isolates GH-1, ROD, ST, BEN, and D194.17 were inserted into E. coli pEX vectors and expression of Nef beta-galactosidase fusion proteins was detected in stained gels. All fusion proteins specifically reacted with a rabbit serum raised against bacterially expressed Nef from HIV-2D194.17. Sera from monkeys inoculated with HIV-2BEN or SIVMAC251 recognized the Nef proteins of only certain HIV-2 isolates. No cross-reactivity of these sera with HIV-1 Nef and of a rabbit anti-HIV-1-Nef serum with the described HIV-2 Nef fusion proteins was observed.

  18. Mycobacterium tuberculosis HspX/EsxS Fusion Protein: Gene Cloning, Protein Expression, and Purification in Escherichia coli.

    Science.gov (United States)

    Khademi, Farzad; Yousefi-Avarvand, Arshid; Derakhshan, Mohammad; Meshkat, Zahra; Tafaghodi, Mohsen; Ghazvini, Kiarash; Aryan, Ehsan; Sankian, Mojtaba

    2017-10-01

    The purpose of this study was to clone, express, and purify a novel multidomain fusion protein of Micobacterium tuberculosis (Mtb) in a prokaryotic system. An hspX/esxS gene construct was synthesized and ligated into a pGH plasmid, E. coli TOP10 cells were transformed, and the vector was purified. The vector containing the construct and pET-21b (+) plasmid were digested with the same enzymes and the construct was ligated into pET-21b (+). The accuracy of cloning was confirmed by colony PCR and sequencing. E. coli BL21 cells were transformed with the pET-21b (+)/hspX/esxS expression vector and protein expression was evaluated. Finally, the expressed fusion protein was purified on a Ni-IDA column and verified by SDS-PAGE and western blotting. The hspX/esxS gene construct was inserted into pET-21b (+) and recombinant protein expression was induced with IPTG in E. coli BL21 cells. Various concentrations of IPTG were tested to determine the optimum concentration for expression induction. The recombinant protein was expressed in insoluble inclusion bodies. Three molar guanidine HCl was used to solubilize the insoluble protein. An HspX/EsxS Mtb fusion protein was expressed in E. coli and the recombinant protein was purified. After immunological analysis, the HspX/EsxS fusion protein might be an anti-tuberculosis vaccine candidate in future clinical trial studies.

  19. Production of recombinant proteins in Escherichia coli tagged with the fusion protein CusF3H.

    Science.gov (United States)

    Vargas-Cortez, Teresa; Morones-Ramirez, Jose Ruben; Balderas-Renteria, Isaias; Zarate, Xristo

    2017-04-01

    Recombinant protein expression in the bacterium Escherichia coli still is the number one choice for large-scale protein production. Nevertheless, many complications can arise using this microorganism, such as low yields, the formation of inclusion bodies, and the requirement for difficult purification steps. Most of these problems can be solved with the use of fusion proteins. Here, the use of the metal-binding protein CusF3H+ is described as a new fusion protein for recombinant protein expression and purification in E. coli. We have previously shown that CusF produces large amounts of soluble protein, with low levels of formation of inclusion bodies, and that proteins can be purified using IMAC resins charged with Cu(II) ions. CusF3H+ is an enhanced variant of CusF, formed by the addition of three histidine residues at the N-terminus. These residues then can bind Ni(II) ions allowing improved purity after affinity chromatography. Expression and purification of Green Fluorescent Protein tagged with CusF3H+ showed that the mutation did not alter the capacity of the fusion protein to increase protein expression, and purity improved considerably after affinity chromatography with immobilized nickel ions; high yields are obtained after tag-removal since CusF3H+ is a small protein of just 10 kDa. Furthermore, the results of experiments involving expression of tagged proteins having medium to large molecular weights indicate that the presence of the CusF3H+ tag improves protein solubility, as compared to a His-tag. We therefore endorse CusF3H+ as a useful alternative fusion protein/affinity tag for production of recombinant proteins in E. coli. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Surface Density of the Hendra G Protein Modulates Hendra F Protein-Promoted Membrane Fusion: Role for Hendra G Protein Trafficking and Degradation

    OpenAIRE

    Whitman, Shannon D.; Dutch, Rebecca Ellis

    2007-01-01

    Hendra virus, like most paramyxoviruses, requires both a fusion (F) and attachment (G) protein for promotion of cell-cell fusion. Recent studies determined that Hendra F is proteolytically processed by the cellular protease cathepsin L after endocytosis. This unique cathepsin L processing results in a small percentage of Hendra F on the cell surface. To determine how the surface densities of the two Hendra glycoproteins affect fusion promotion, we performed experiments that varied the levels ...

  1. Trophoblast cell fusion and differentiation are mediated by both the protein kinase C and a pathways.

    Directory of Open Access Journals (Sweden)

    Waka Omata

    Full Text Available The syncytiotrophoblast of the human placenta is an epithelial barrier that interacts with maternal blood and is a key for the transfer of nutrients and other solutes to the developing fetus. The syncytiotrophoblast is a true syncytium and fusion of progenitor cytotrophoblasts is the cardinal event leading to the formation of this layer. BeWo cells are often used as a surrogate for cytotrophoblasts, since they can be induced to fuse, and then express certain differentiation markers associated with trophoblast syncytialization. Dysferlin, a syncytiotrophoblast membrane repair protein, is up-regulated in BeWo cells induced to fuse by treatment with forskolin; this fusion is thought to occur through cAMP/protein kinase A-dependent mechanisms. We hypothesized that dysferlin may also be up-regulated in response to fusion through other pathways. Here, we show that BeWo cells can also be induced to fuse by treatment with an activator of protein kinase C, and that this fusion is accompanied by increased expression of dysferlin. Moreover, a dramatic synergistic increase in dysferlin expression is observed when both the protein kinase A and protein kinase C pathways are activated in BeWo cells. This synergy in fusion is also accompanied by dramatic increases in mRNA for the placental fusion proteins syncytin 1, syncytin 2, as well as dysferlin. Dysferlin, however, was shown to be dispensable for stimulus-induced BeWo cell syncytialization, since dysferlin knockdown lines fused to the same extent as control cells. The classical trophoblast differentiation marker human chorionic gonadotropin was also monitored and changes in the expression closely parallel that of dysferlin in all of the experimental conditions employed. Thus different biochemical markers of trophoblast fusion behave in concert supporting the hypothesis that activation of both protein kinase C and A pathways lead to trophoblastic differentiation.

  2. Purification of CD47-streptavidin fusion protein from bacterial lysate using biotin-agarose affinity chromatography.

    Science.gov (United States)

    Salehi, Nasrin; Peng, Ching-An

    2016-07-08

    CD47 is a widely expressed transmembrane glycoprotein that modulates the activity of a plethora of immune cells via its extracellular domain. Therefore, CD47 plays important roles in the regulation of immune responses and may serve as targets for the development of immunotherapeutic agents. To make sure CD47 functionality is intact under the process of protein conjugation, CD47-streptavidin fusion protein was expressed and purified because it can easily bind to biotin-tagged materials via the unique biotin-streptavidin affinity. In this study, gene sequences of CD47 extracellular domain (CD47ECD) and core streptavidin (coreSA) with a total 834 bp were inserted into pET20b plasmid to construct recombinant plasmid encoding CD47-SA fusion gene. After bacteria transformation, the CD47-SA fusion protein was expressed by isopropyl-β-d-thiogalactopyranoside (IPTG) induction. The collected bacteria lysate was loaded on biotinylated agarose to proceed the purification of CD47-SA fusion protein. Due to the unexpected high affinity between biotin and coreSA, standard washing and elution approaches (e.g., varying pH, using biotin, and applying guanidine hydrochloride) reported for biotin-streptavidin affinity chromatography were not able to separate the target fusion protein. Instead, using low concentration of the non-ionic detergent Triton X-100 followed with alkaline buffer could efficiently weaken the binding between biotin and coreSA, thereby eluting out CD47-SA fusion protein from the biotin agarose column. The purified CD47-SA fusion protein was further characterized by molecular biology methods and its antiphagocytic functionality was confirmed by the phagocytosis assay. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:949-958, 2016. © 2016 American Institute of Chemical Engineers.

  3. Protein solubility and differential proteomic profiling of recombinant Escherichia coli overexpressing double-tagged fusion proteins.

    Science.gov (United States)

    Cheng, Chung-Hsien; Lee, Wen-Chien

    2010-08-28

    Overexpression of recombinant proteins usually triggers the induction of heat shock proteins that regulate aggregation and solubility of the overexpressed protein. The two-dimensional gel electrophoresis (2-DE)-mass spectrometry approach was used to profile the proteome of Escherichia coli overexpressing N-acetyl-D-glucosamine 2-epimerase (GlcNAc 2-epimerase) and N-acetyl-D-neuraminic acid aldolase (Neu5Ac aldolase), both fused to glutathione S-transferase (GST) and polyionic peptide (5D or 5R). Overexpression of fusion proteins by IPTG induction caused significant differential expression of numerous cellular proteins; most of these proteins were down-regulated, including enzymes connected to the pentose phosphate pathway and the enzyme LuxS that could lead to an inhibition of tRNA synthesis. Interestingly, when plasmid-harboring cells were cultured in LB medium, gluconeogenesis occurred mainly through MaeB, while in the host strain, gluconeogenesis occurred by a different pathway (by Mdh and PckA). Significant up-regulation of the chaperones ClpB, HslU and GroEL and high-level expression of two protective small heat shock proteins (IbpA and IbpB) were found in cells overexpressing GST-GlcNAc 2-epimerase-5D but not in GST-Neu5Ac aldolase-5R-expressing E. coli. Although most of the recombinant protein was present in insoluble aggregates, the soluble fraction of GST-GlcNAc 2-epimerase-5D was higher than that of GST-Neu5Ac aldolase-5R. Also, in cells overexpressing recombinant GST-GlcNAc 2-epimerase-5D, the expression of σ32 was maintained at a higher level following induction. Differential expression of metabolically functional proteins, especially those in the gluconeogenesis pathway, was found between host and recombinant cells. Also, the expression patterns of chaperones/heat shock proteins differed among the plasmid-harboring bacteria in response to overproduction of recombinant proteins. In conclusion, the solubility of overexpressed recombinant proteins could

  4. Naturally-occurring, dually-functional fusions between restriction endonucleases and regulatory proteins.

    Science.gov (United States)

    Liang, Jixiao; Blumenthal, Robert M

    2013-10-02

    Restriction-modification (RM) systems appear to play key roles in modulating gene flow among bacteria and archaea. Because the restriction endonuclease (REase) is potentially lethal to unmethylated new host cells, regulation to ensure pre-expression of the protective DNA methyltransferase (MTase) is essential to the spread of RM genes. This is particularly true for Type IIP RM systems, in which the REase and MTase are separate, independently-active proteins. A substantial subset of Type IIP RM systems are controlled by an activator-repressor called C protein. In these systems, C controls the promoter for its own gene, and for the downstream REase gene that lacks its own promoter. Thus MTase is expressed immediately after the RM genes enter a new cell, while expression of REase is delayed until sufficient C protein accumulates. To study the variation in and evolution of this regulatory mechanism, we searched for RM systems closely related to the well-studied C protein-dependent PvuII RM system. Unexpectedly, among those found were several in which the C protein and REase genes were fused. The gene for CR.NsoJS138I fusion protein (nsoJS138ICR, from the bacterium Niabella soli) was cloned, and the fusion protein produced and partially purified. Western blots provided no evidence that, under the conditions tested, anything other than full-length fusion protein is produced. This protein had REase activity in vitro and, as expected from the sequence similarity, its specificity was indistinguishable from that for PvuII REase, though the optimal reaction conditions were different. Furthermore, the fusion was active as a C protein, as revealed by in vivo activation of a lacZ reporter fusion to the promoter region for the nsoJS138ICR gene. Fusions between C proteins and REases have not previously been characterized, though other fusions have (such as between REases and MTases). These results reinforce the evidence for impressive modularity among RM system proteins, and raise

  5. Immunogenicity and Protective Efficacy of a Fusion Protein Tuberculosis Vaccine Combining Five Esx Family Proteins.

    Science.gov (United States)

    Xiang, Zhi-Hao; Sun, Rui-Feng; Lin, Chen; Chen, Fu-Zeng; Mai, Jun-Tao; Liu, Yu-Xiao; Xu, Zi-Yan; Zhang, Lu; Liu, Jun

    2017-01-01

    One strategy to develop the next generation of tuberculosis vaccines is to construct subunit vaccines based on T cell antigens. In this study, we have evaluated the vaccine potential of a fusion protein combining EsxB, EsxD, EsxG, EsxU, and EsxM of Mycobacterium tuberculosis ( M. tb ). This recombinant protein, named BM, was expressed in and purified from Escherichia coli . Immunization of C57BL/6 mice with purified BM protein formulated in Freund's incomplete adjuvant induced the production of Th1 cytokines (IFN-γ, TNF, and IL-2) and multifunctional CD4 + T cells. Vaccination of BALB/c mice with BM protein followed by intravenous challenge with Mycobacterium bovis BCG resulted in better levels of protection than the two leading antigens, Ag85A and PPE18. Taken together, these results indicate that BM is a protective antigen. Future studies to combine BM with other antigens and evaluate its effectiveness as a booster of BCG or as a therapeutic vaccine are warranted.

  6. Expression,purification and cell penetrativity of fusion protein PDT/GR-ΔLBD

    Directory of Open Access Journals (Sweden)

    Fang ZHANG

    2011-01-01

    Full Text Available Objective To construct the fusion gene expression vector of penetrating peptide(PDT and the glucocorticoid receptor lack of ligand binding domain(GR-ΔLBD,and evaluate the prokaryotic expression,purification and cell penetrativity of fusion protein PDT/GR-ΔLBD.Methods The target gene fragment GR-ΔLBD was obtained from plasmid pEGFP-GR-ΔLBD by double digestion,and sub-cloned into the prokaryotic expression vector pGEX-PDT to construct the fusion gene expression vector pGEX-PDT/GR-ΔLBD.PDT/GR-ΔLBD fusion protein was obtained after the expression vector was transformed into E.coli,followed by sequential induction with IPTG,treatment with glutathione-agarose resin and elution with glutathione.SDS-PAGE was performed to determine the expression of PDT/GR-ΔLBD fusion protein,and it which was diluted into a final concentration of 0,500 and 1000nmol/L,labeled with fluorescein FITC and co-cultivated with TC-1 cells for 2 hours,and the penetrativity was observed by fluorescence microscopy.Results The successfully constructed prokaryotic expression vector pPDT/GR-ΔLBD had the capacity of expressing protein,and it was 78.6kD in molecular weight,which was consistent with the theoretical value(80kD of the fusion protein PDT/GR-ΔLBD.PDT-GR-ΔLBD,penetrating the nuclear membrane in a concentration-dependent manner,was concentrated within nuclei.Conclusion PDT/GR-ΔLBD fusion protein,with good solubility and cell penetrativity,paves the way for further research on its anti-inflammatory effects.

  7. Beyond anchoring: the expanding role of the hendra virus fusion protein transmembrane domain in protein folding, stability, and function.

    Science.gov (United States)

    Smith, Everett Clinton; Culler, Megan R; Hellman, Lance M; Fried, Michael G; Creamer, Trevor P; Dutch, Rebecca Ellis

    2012-03-01

    While work with viral fusion proteins has demonstrated that the transmembrane domain (TMD) can affect protein folding, stability, and membrane fusion promotion, the mechanism(s) remains poorly understood. TMDs could play a role in fusion promotion through direct TMD-TMD interactions, and we have recently shown that isolated TMDs from three paramyxovirus fusion (F) proteins interact as trimers using sedimentation equilibrium (SE) analysis (E. C. Smith, et al., submitted for publication). Immediately N-terminal to the TMD is heptad repeat B (HRB), which plays critical roles in fusion. Interestingly, addition of HRB decreased the stability of the trimeric TMD-TMD interactions. This result, combined with previous findings that HRB forms a trimeric coiled coil in the prefusion form of the whole protein though HRB peptides fail to stably associate in isolation, suggests that the trimeric TMD-TMD interactions work in concert with elements in the F ectodomain head to stabilize a weak HRB interaction. Thus, changes in TMD-TMD interactions could be important in regulating F triggering and refolding. Alanine insertions between the TMD and HRB demonstrated that spacing between these two regions is important for protein stability while not affecting TMD-TMD interactions. Additional mutagenesis of the C-terminal end of the TMD suggests that β-branched residues within the TMD play a role in membrane fusion, potentially through modulation of TMD-TMD interactions. Our results support a model whereby the C-terminal end of the Hendra virus F TMD is an important regulator of TMD-TMD interactions and show that these interactions help hold HRB in place prior to the triggering of membrane fusion.

  8. Tandem SUMO fusion vectors for improving soluble protein expression and purification.

    Science.gov (United States)

    Guerrero, Fernando; Ciragan, Annika; Iwaï, Hideo

    2015-12-01

    Availability of highly purified proteins in quantity is crucial for detailed biochemical and structural investigations. Fusion tags are versatile tools to facilitate efficient protein purification and to improve soluble overexpression of proteins. Various purification and fusion tags have been widely used for overexpression in Escherichia coli. However, these tags might interfere with biological functions and/or structural investigations of the protein of interest. Therefore, an additional purification step to remove fusion tags by proteolytic digestion might be required. Here, we describe a set of new vectors in which yeast SUMO (SMT3) was used as the highly specific recognition sequence of ubiquitin-like protease 1, together with other commonly used solubility enhancing proteins, such as glutathione S-transferase, maltose binding protein, thioredoxin and trigger factor for optimizing soluble expression of protein of interest. This tandem SUMO (T-SUMO) fusion system was tested for soluble expression of the C-terminal domain of TonB from different organisms and for the antiviral protein scytovirin. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Rational design of a fusion partner for membrane protein expression in E. coli.

    Science.gov (United States)

    Luo, Jianying; Choulet, Julie; Samuelson, James C

    2009-08-01

    We have designed a novel protein fusion partner (P8CBD) to utilize the co-translational SRP pathway in order to target heterologous proteins to the E. coli inner membrane. SRP-dependence was demonstrated by analyzing the membrane translocation of P8CBD-PhoA fusion proteins in wt and SRP-ffh77 mutant cells. We also demonstrate that the P8CBD N-terminal fusion partner promotes over-expression of a Thermotoga maritima polytopic membrane protein by replacement of the native signal anchor sequence. Furthermore, the yeast mitochondrial inner membrane protein Oxa1p was expressed as a P8CBD fusion and shown to function within the E. coli inner membrane. In this example, the mitochondrial targeting peptide was replaced by P8CBD. Several practical features were incorporated into the P8CBD expression system to aid in protein detection, purification, and optional in vitro processing by enterokinase. The basis of membrane protein over-expression toxicity is discussed and solutions to this problem are presented. We anticipate that this optimized expression system will aid in the isolation and study of various recombinant forms of membrane-associated protein.

  10. Construction of dystrophin fusion proteins to raise targeted antibodies to different epitopes

    NARCIS (Netherlands)

    Ginjaar, H. B.; van Paassen, H. B.; den Dunnen, J. T.; Man, N. T.; Morris, G. E.; Moorman, A. F.; van Ommen, G. J.

    1992-01-01

    For the study of the structure and function relationship of dystrophin, defective in DMD, and for diagnostic purposes it is important to dispose of antibodies against different parts of the protein. We have made five different constructs for the expression of fusion proteins containing parts of the

  11. Residues in the Hendra Virus Fusion Protein Transmembrane Domain Are Critical for Endocytic Recycling

    OpenAIRE

    Popa, Andreea; Carter, James R.; Smith, Stacy E.; Hellman, Lance; Fried, Michael G.; Dutch, Rebecca Ellis

    2012-01-01

    Hendra virus is a highly pathogenic paramyxovirus classified as a biosafety level four agent. The fusion (F) protein of Hendra virus is critical for promoting viral entry and cell-to-cell fusion. To be fusogenically active, Hendra virus F must undergo endocytic recycling and cleavage by the endosomal/lysosomal protease cathepsin L, but the route of Hendra virus F following internalization and the recycling signals involved are poorly understood. We examined the intracellular distribution of H...

  12. Two single mutations in the fusion protein of Newcastle disease virus confer hemagglutinin-neuraminidase independent fusion promotion and attenuate the pathogenicity in chickens

    Science.gov (United States)

    The fusion (F) protein of Newcastle disease virus (NDV) plays an important role in viral infection and pathogenicity through mediating membrane fusion between the virion and host cells in the presence of the hemagglutinin-neuraminidase (HN). Previously, we obtained a velogenic NDV genotype VII muta...

  13. IGF1 is a common target gene of Ewing's sarcoma fusion proteins in mesenchymal progenitor cells.

    Directory of Open Access Journals (Sweden)

    Luisa Cironi

    Full Text Available BACKGROUND: The EWS-FLI-1 fusion protein is associated with 85-90% of Ewing's sarcoma family tumors (ESFT, the remaining 10-15% of cases expressing chimeric genes encoding EWS or FUS fused to one of several ets transcription factor family members, including ERG-1, FEV, ETV1 and ETV6. ESFT are dependent on insulin-like growth factor-1 (IGF-1 for growth and survival and recent evidence suggests that mesenchymal progenitor/stem cells constitute a candidate ESFT origin. METHODOLOGY/PRINCIPAL FINDINGS: To address the functional relatedness between ESFT-associated fusion proteins, we compared mouse progenitor cell (MPC permissiveness for EWS-FLI-1, EWS-ERG and FUS-ERG expression and assessed the corresponding expression profile changes. Whereas all MPC isolates tested could stably express EWS-FLI-1, only some sustained stable EWS-ERG expression and none could express FUS-ERG for more than 3-5 days. Only 14% and 4% of the total number of genes that were respectively induced and repressed in MPCs by the three fusion proteins were shared. However, all three fusion proteins, but neither FLI-1 nor ERG-1 alone, activated the IGF1 promoter and induced IGF1 expression. CONCLUSION/SIGNIFICANCE: Whereas expression of different ESFT-associated fusion proteins may require distinct cellular microenvironments and induce transcriptome changes of limited similarity, IGF1 induction may provide one common mechanism for their implication in ESFT pathogenesis.

  14. [Construction and expression of recombinant human serum albumin-EPO fusion protein].

    Science.gov (United States)

    Huang, Ying-Chun; Gou, Xing-Hua; Han, Lei; Li, De-Hua; Zhao, Lan-Ying; Wu, Qia-Qing

    2011-05-01

    OBJECTIVE To construct the recombinant plasmid pCI-HLE encoding human serum album-EPO (HSA-EPO) fusion protein and to express it in CHO cell. The cDNA encoding human serum album and EPO were amplified by PCR, and then spliced with the synsitic DNA fragment encoding GS (GGGGS), by overlap PCR extension to form LEPO. After BamH I digestion, the HSA and LEPO was ligated to generate the fusion HSA-EPO gene and was then cloned into the expression vector pCI-neo to generate the recombinant plasmid pCI-HLE. The plasmid pCI-HLE was transfected into CHO cell by liposome protocol. Then, the recombinant cells were screened by G418 and identified by PCR and Western blot. Expression of fusion protein was evaluated by Enzyme Linked Immunosorbent Assay (ELISA). Restrictive enzymes digestion and DNA sequencing revealed that HSA-EPO fusion gene was cloned into expression vector pCI-neo successfully. PCR and Western blot analysis confirmed that the fusion gene was integrated in the genome of CHO cells and expressed successfully. The HSA-EPO production varied from 86 Iu/(mL x 10(6) x 72 h) to 637 IU/(mLx 10(6) x 72 h). The results confirmed that HSA-EPO fusion gene can be expressed in the CHO cells, with EPO immunogenicity, which could serve as foundation for the development of long-lasting recombinant HSA-EPO protein.

  15. Egg CD9 protein tides correlated with sperm oscillations tune the gamete fusion ability in mammal.

    Science.gov (United States)

    Ravaux, Benjamin; Favier, Sophie; Perez, Eric; Gourier, Christine

    2018-01-23

    Mammalian fertilization involves membrane events -adhesion, fusion, sperm engulfment, membrane block to polyspermy- whose causes remain largely unknown. Recently, specific oscillations of the sperm in contact with the egg were shown to be necessary for fusion. Using a microfluidic chip to impose the venue for the encounter of two gametes allowed real-time observation of the membrane remodelling occurring at the sperm/egg interface. The spatiotemporal mapping of egg CD9 revealed that this protein concentrates at the egg/sperm interface as a result of sperm oscillations, until a CD9-rich platform is nucleated on which fusion immediately takes place. Within 2 to 5 minutes after fusion, most of the CD9 leaves the egg for the external aqueous medium. Then an egg membrane wave engulfs the sperm head in approximately 25 minutes. These results show that sperm oscillations initiate the CD9 recruitment that causes gamete fusion after which CD9 and associated proteins leave the membrane in a process likely to contribute to block polyspermy. They highlight that the gamete fusion story in mammals is an unexpected interplay between mechanical constraints and proteins. © The Author(s) (2018). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

  16. Characterization of protective immune responses induced by pneumococcal surface protein A in fusion with pneumolysin derivatives.

    Directory of Open Access Journals (Sweden)

    Cibelly Goulart

    Full Text Available Pneumococcal surface protein A (PspA and Pneumolysin derivatives (Pds are important vaccine candidates, which can confer protection in different models of pneumococcal infection. Furthermore, the combination of these two proteins was able to increase protection against pneumococcal sepsis in mice. The present study investigated the potential of hybrid proteins generated by genetic fusion of PspA fragments to Pds to increase cross-protection against fatal pneumococcal infection. Pneumolisoids were fused to the N-terminus of clade 1 or clade 2 pspA gene fragments. Mouse immunization with the fusion proteins induced high levels of antibodies against PspA and Pds, able to bind to intact pneumococci expressing a homologous PspA with the same intensity as antibodies to rPspA alone or the co-administered proteins. However, when antibody binding to pneumococci with heterologous PspAs was examined, antisera to the PspA-Pds fusion molecules showed stronger antibody binding and C3 deposition than antisera to co-administered proteins. In agreement with these results, antisera against the hybrid proteins were more effective in promoting the phagocytosis of bacteria bearing heterologous PspAs in vitro, leading to a significant reduction in the number of bacteria when compared to co-administered proteins. The respective antisera were also capable of neutralizing the lytic activity of Pneumolysin on sheep red blood cells. Finally, mice immunized with fusion proteins were protected against fatal challenge with pneumococcal strains expressing heterologous PspAs. Taken together, the results suggest that PspA-Pd fusion proteins comprise a promising vaccine strategy, able to increase the immune response mediated by cross-reactive antibodies and complement deposition to heterologous strains, and to confer protection against fatal challenge.

  17. Characterization of the fusion core in zebrafish endogenous retroviral envelope protein

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jian [State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072 (China); State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei 430071 (China); Zhang, Huaidong [CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei 430071 (China); Gong, Rui, E-mail: gongr@wh.iov.cn [CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei 430071 (China); Xiao, Gengfu, E-mail: xiaogf@wh.iov.cn [State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072 (China); State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei 430071 (China)

    2015-05-08

    Zebrafish endogenous retrovirus (ZFERV) is the unique endogenous retrovirus in zebrafish, as yet, containing intact open reading frames of its envelope protein gene in zebrafish genome. Similarly, several envelope proteins of endogenous retroviruses in human and other mammalian animal genomes (such as syncytin-1 and 2 in human, syncytin-A and B in mouse) were identified and shown to be functional in induction of cell–cell fusion involved in placental development. ZFERV envelope protein (Env) gene appears to be also functional in vivo because it is expressible. After sequence alignment, we found ZFERV Env shares similar structural profiles with syncytin and other type I viral envelopes, especially in the regions of N- and C-terminal heptad repeats (NHR and CHR) which were crucial for membrane fusion. We expressed the regions of N + C protein in the ZFERV Env (residues 459–567, including predicted NHR and CHR) to characterize the fusion core structure. We found N + C protein could form a stable coiled-coil trimer that consists of three helical NHR regions forming a central trimeric core, and three helical CHR regions packing into the grooves on the surface of the central core. The structural characterization of the fusion core revealed the possible mechanism of fusion mediated by ZFERV Env. These results gave comprehensive explanation of how the ancient virus infects the zebrafish and integrates into the genome million years ago, and showed a rational clue for discovery of physiological significance (e.g., medicate cell–cell fusion). - Highlights: • ZFERV Env shares similar structural profiles with syncytin and other type I viral envelopes. • The fusion core of ZFERV Env forms stable coiled-coil trimer including three NHRs and three CHRs. • The structural mechanism of viral entry mediated by ZFERV Env is disclosed. • The results are helpful for further discovery of physiological function of ZFERV Env in zebrafish.

  18. A minichaperone-based fusion system for producing insoluble proteins in soluble stable forms.

    Science.gov (United States)

    Sharapova, Olga A; Yurkova, Maria S; Fedorov, Alexey N

    2016-02-01

    We have developed a fusion system for reliable production of insoluble hydrophobic proteins in soluble stable forms. A carrier is thermophilic minichaperone, GroEL apical domain (GrAD), a 15 kDa monomer able to bind diverse protein substrates. The Met-less variant of GrAD has been made for further convenient use of Met-specific CNBr chemical cleavage, if desired. The Met-less GrAD retained stability and solubility of the original protein. Target polypeptides can be fused to either C-terminus or N-terminus of GrAD. The system has been tested with two unrelated insoluble proteins fused to the C-terminus of GrAD. One of the proteins was also fused to GrAD N-terminus. The fusions formed inclusion bodies at 25°C and above and were partly soluble only at lower expression temperatures. Most importantly, however, after denaturation in urea, all fusions without exception were completely renatured in soluble stable forms that safely survived freezing-thawing as well as lyophilization. All fusions for both tested target proteins retained solubility at high concentrations for days. Functional analysis revealed that a target protein may retain functionality in the fusion. Convenience features include potential thermostability of GrAD fusions, capacity for chemical and enzymatic cleavage of a target and His6 tag for purification. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  19. Induction of protein body formation in plant leaves by elastin-like polypeptide fusions

    Directory of Open Access Journals (Sweden)

    Joensuu Jussi J

    2009-08-01

    Full Text Available Abstract Background Elastin-like polypeptides are synthetic biopolymers composed of a repeating pentapeptide 'VPGXG' sequence that are valuable for the simple non-chromatographic purification of recombinant proteins. In addition, elastin-like polypeptide fusions have been shown to enhance the accumulation of a range of different recombinant proteins in plants, thus addressing the major limitation of plant-based expression systems, which is a low production yield. This study's main objectives were to determine the general utility of elastin-like polypeptide protein fusions in various intracellular compartments and to elucidate elastin-like polypeptide's mechanism of action for increasing recombinant protein accumulation in the endoplasmic reticulum of plants. Results The effect of elastin-like polypeptide fusions on the accumulation of green fluorescent protein targeted to the cytoplasm, chloroplasts, apoplast, and endoplasmic reticulum was evaluated. The endoplasmic reticulum was the only intracellular compartment in which an elastin-like polypeptide tag was shown to significantly enhance recombinant protein accumulation. Interestingly, endoplasmic reticulum-targeted elastin-like polypeptide fusions induced the formation of a novel type of protein body, which may be responsible for elastin-like polypeptide's positive effect on recombinant protein accumulation by excluding the heterologous protein from normal physiological turnover. Although expressed in the leaves of plants, these novel protein bodies appeared similar in size and morphology to the prolamin-based protein bodies naturally found in plant seeds. The elastin-like polypeptide-induced protein bodies were highly mobile organelles, exhibiting various dynamic patterns of movement throughout the cells, which were dependent on intact actin microfilaments and a functional actomyosin motility system. Conclusion An endoplasmic reticulum-targeted elastin-like polypeptide fusion approach

  20. Mechanistic insight provided by glutaredoxin within a fusion to redox-sensitive yellow fluorescent protein

    DEFF Research Database (Denmark)

    Björnberg, Olof; Østergaard, Henrik; Winther, Jakob R

    2006-01-01

    have generated a fusion of the two proteins, rxYFP-Grx1p. In comparison to isolated subunits, intramolecular transfer of reducing equivalents made the fusion protein kinetically superior in reactions with glutathione. The rate of GSSG oxidation was thus improved by a factor of 3300. The reaction......Redox-sensitive yellow fluorescent protein (rxYFP) contains a dithiol disulfide pair that is thermodynamically suitable for monitoring intracellular glutathione redox potential. Glutaredoxin 1 (Grx1p) from yeast is known to catalyze the redox equilibrium between rxYFP and glutathione, and here, we...... separately and in the fusion. This could not be ascribed to the lack of an unproductive side reaction to glutaredoxin disulfide. Instead, slower alkylation kinetics with iodoacetamide indicates a better leaving-group capability of the remaining cysteine residue, which can explain the increased activity....

  1. Protein NCRII-18: the role of gene fusion in the molecular evolution of restriction endonucleases.

    Science.gov (United States)

    Ibryashkina, Elena M; Solonin, Alexander S; Zakharova, Marina V

    2017-06-01

    This work first constructed the fusion protein NCRII-18 by fusing the restriction endonuclease Ecl18kI gene and part of the gene coding for the N-terminal domain of the endonuclease EcoRII. The fusion of the EcoRII N-terminal domain leads to a change in the properties of the recombinant protein. Unlike Ecl18kI, which made the basis of NCRII-18, the fusion protein predominantly recognizes the CCWGG sites, having lost the capability of interacting with the CCSGG sites. Experimental data support the hypothesis of a close evolutionary relationship between type IIE and IIP restriction endonucleases via a recombination between domains with active site structure and elements for recognition with domains responsible for recognition of DNA sequences. © 2017 Federation of European Biochemical Societies.

  2. Simple purification of a foreign protein using polyhedrin fusion in a baculovirus expression system.

    Science.gov (United States)

    Roh, Jong Yul; Choi, Jae Young; Kang, Joong Nam; Wang, Yong; Shim, Hee Jin; Liu, Qin; Tao, Xueying; Xu, Hong Guang; Hyun, Jin-Ho; Woo, Soo Dong; Jin, Byung Rae; Je, Yeon Ho

    2010-01-01

    Previously, we found that expression by translational fusion of the polyhedrin (Polh)-green fluorescence protein (GFP) led to the formation of granular structures, and that these fluorescent granules were easily precipitated by high-speed centrifugation. Here, we developed an easy, fast, mass purification system using this baculovirus expression system (BES). An enhanced GFP (EGFP) fused with the Polh gene at the N-terminus, including a linker and enterokinase (EK) site between Polh and EGFP, was expressed in Sf9 cells. The cells infected by AcPolhEKA-EGFP produced fluorescent granules. The EGFP fusion protein was purified from granule-containing cells in three steps: cell harvest, sonication, and EK digestion. Through final enterokinase digestion, EGFP presented mainly in the supernatant, and this supernatant fraction also showed a pure EGFP band. These results suggest that a combined procedure of Polh fusion expression and enterokinase digestion can be used for rapid and easy purification of other proteins.

  3. Bone Morphogenetic Proteins in Anterior Cervical Fusion: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Zadegan, Shayan Abdollah; Abedi, Aidin; Jazayeri, Seyed Behnam; Nasiri Bonaki, Hirbod; Jazayeri, Seyed Behzad; Vaccaro, Alexander R; Rahimi-Movaghar, Vafa

    2017-08-01

    Bone morphogenetic proteins (BMPs) have been commonly used as a graft substitute in spinal fusion. Although the U.S. Food and Drug Administration issued a warning on life-threatening complications of recombinant human BMPs (rhBMPs) in cervical spine fusion in 2008, their off-label use has been continued. This investigation aimed to review the evidence for the use of rhBMP-2 and rhBMP-7 in anterior cervical spine fusions. A comprehensive search was performed through Ovid (MEDLINE), PubMed, and Embase. The risk of bias assessment was according to the recommended criteria by the Cochrane Back and Neck group and MINORS (Methodological Index for Non-Randomized Studies). A wide array of radiographic and clinical outcomes including the adverse events were collated. Eighteen articles (1 randomized and 17 nonrandomized) were eligible for inclusion. The fusion rate was higher with use of rhBMP in most studies and our meta-analysis of the pooled data from 4782 patients confirmed this finding (odds ratio, 5.45; P fusion yields a significantly higher fusion rate with similar patient-reported outcomes, yet increased risk of life-threatening complications. Thus, we do not recommend the use of rhBMP in anterior cervical fusions. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Localized cyclic AMP-dependent protein kinase activity is required for myogenic cell fusion

    International Nuclear Information System (INIS)

    Mukai, Atsushi; Hashimoto, Naohiro

    2008-01-01

    Multinucleated myotubes are formed by fusion of mononucleated myogenic progenitor cells (myoblasts) during terminal skeletal muscle differentiation. In addition, myoblasts fuse with myotubes, but terminally differentiated myotubes have not been shown to fuse with each other. We show here that an adenylate cyclase activator, forskolin, and other reagents that elevate intracellular cyclic AMP (cAMP) levels induced cell fusion between small bipolar myotubes in vitro. Then an extra-large myotube, designated a 'myosheet,' was produced by both primary and established mouse myogenic cells. Myotube-to-myotube fusion always occurred between the leading edge of lamellipodia at the polar end of one myotube and the lateral plasma membrane of the other. Forskolin enhanced the formation of lamellipodia where cAMP-dependent protein kinase (PKA) was accumulated. Blocking enzymatic activity or anchoring of PKA suppressed forskolin-enhanced lamellipodium formation and prevented fusion of multinucleated myotubes. Localized PKA activity was also required for fusion of mononucleated myoblasts. The present results suggest that localized PKA plays a pivotal role in the early steps of myogenic cell fusion, such as cell-to-cell contact/recognition through lamellipodium formation. Furthermore, the localized cAMP-PKA pathway might be involved in the specification of the fusion-competent areas of the plasma membrane in lamellipodia of myogenic cells

  5. In Vivo Immobilization of Fusion Proteins on Bioplastics by the Novel Tag BioF

    Science.gov (United States)

    Moldes, Cristina; García, Pedro; García, José L.; Prieto, María A.

    2004-01-01

    A new protein immobilization and purification system has been developed based on the use of polyhydroxyalkanoates (PHAs, or bioplastics), which are biodegradable polymers accumulated as reserve granules in the cytoplasm of certain bacteria. The N-terminal domain of the PhaF phasin (a PHA-granule-associated protein) from Pseudomonas putida GPo1 was used as a polypeptide tag (BioF) to anchor fusion proteins to PHAs. This tag provides a novel way to immobilize proteins in vivo by using bioplastics as supports. The granules carrying the BioF fusion proteins can be isolated by a simple centrifugation step and used directly for some applications. Moreover, when required, a practically pure preparation of the soluble BioF fusion protein can be obtained by a mild detergent treatment of the granule. The efficiency of this system has been demonstrated by constructing two BioF fusion products, including a functional BioF-β-galactosidase. This is the first example of an active bioplastic consisting of a biodegradable matrix carrying an active enzyme. PMID:15184113

  6. The Ancient Gamete Fusogen HAP2 Is a Eukaryotic Class II Fusion Protein.

    Science.gov (United States)

    Fédry, Juliette; Liu, Yanjie; Péhau-Arnaudet, Gérard; Pei, Jimin; Li, Wenhao; Tortorici, M Alejandra; Traincard, François; Meola, Annalisa; Bricogne, Gérard; Grishin, Nick V; Snell, William J; Rey, Félix A; Krey, Thomas

    2017-02-23

    Sexual reproduction is almost universal in eukaryotic life and involves the fusion of male and female haploid gametes into a diploid cell. The sperm-restricted single-pass transmembrane protein HAP2-GCS1 has been postulated to function in membrane merger. Its presence in the major eukaryotic taxa-animals, plants, and protists (including important human pathogens like Plasmodium)-suggests that many eukaryotic organisms share a common gamete fusion mechanism. Here, we report combined bioinformatic, biochemical, mutational, and X-ray crystallographic studies on the unicellular alga Chlamydomonas reinhardtii HAP2 that reveal homology to class II viral membrane fusion proteins. We further show that targeting the segment corresponding to the fusion loop by mutagenesis or by antibodies blocks gamete fusion. These results demonstrate that HAP2 is the gamete fusogen and suggest a mechanism of action akin to viral fusion, indicating a way to block Plasmodium transmission and highlighting the impact of virus-cell genetic exchanges on the evolution of eukaryotic life. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  7. High-level expression of soluble recombinant proteins in Escherichia coli using an HE-maltotriose-binding protein fusion tag.

    Science.gov (United States)

    Han, Yingqian; Guo, Wanying; Su, Bingqian; Guo, Yujie; Wang, Jiang; Chu, Beibei; Yang, Guoyu

    2018-02-01

    Recombinant proteins are commonly expressed in prokaryotic expression systems for large-scale production. The use of genetically engineered affinity and solubility enhancing fusion proteins has increased greatly in recent years, and there now exists a considerable repertoire of these that can be used to enhance the expression, stability, solubility, folding, and purification of their fusion partner. Here, a modified histidine tag (HE) used as an affinity tag was employed together with a truncated maltotriose-binding protein (MBP; consisting of residues 59-433) from Pyrococcus furiosus as a solubility enhancing tag accompanying a tobacco etch virus protease-recognition site for protein expression and purification in Escherichia coli. Various proteins tagged at the N-terminus with HE-MBP(Pyr) were expressed in E. coli BL21(DE3) cells to determine expression and solubility relative to those tagged with His6-MBP or His6-MBP(Pyr). Furthermore, four HE-MBP(Pyr)-fused proteins were purified by immobilized metal affinity chromatography to assess the affinity of HE with immobilized Ni 2+ . Our results showed that HE-MBP(Pyr) represents an attractive fusion protein allowing high levels of soluble expression and purification of recombinant protein in E. coli. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. SNaPe: a versatile method to generate multiplexed protein fusions using synthetic linker peptides for in vitro applications.

    Science.gov (United States)

    Ulrich, Veronika; Cryle, Max J

    2017-01-01

    Understanding the structure and function of protein complexes and multi-domain proteins is highly important in biology, although the in vitro characterization of these systems is often complicated by their size or the transient nature of protein/protein interactions. To assist in the characterization of such protein complexes, we have developed a modular approach to fusion protein generation that relies upon Sortase-mediated and Native chemical ligation using synthetic Peptide linkers (SNaPe) to link two separately expressed proteins. In this approach, we utilize two separate linking steps - sortase-mediated and native chemical ligation - together with a library of peptide linkers to generate libraries of fusion proteins. We have demonstrated the viability of SNaPe to generate libraries from fusion protein constructs taken from the biosynthetic enzymes responsible for late stage aglycone assembly during glycopeptide antibiotic biosynthesis. Crucially, SNaPe was able to generate fusion proteins that are inaccessible via direct expression of the fusion construct itself. This highlights the advantages of SNaPe to not only access fusion proteins that have been previously unavailable for biochemical and structural characterization but also to do so in a manner that enables the linker itself to be controlled as an experimental parameter of fusion protein generation. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  9. Ubiquitin-like prokaryotic MoaD as a fusion tag for expression of heterologous proteins in Escherichia coli.

    Science.gov (United States)

    Yuan, Sujuan; Wang, Xin; Xu, Jian; Yan, Zheng; Wang, Nan

    2014-01-21

    Eukaryotic ubiquitin and SUMO are frequently used as tags to enhance the fusion protein expression in microbial host. They increase the solubility and stability, and protect the peptides from proteolytic degradation due to their stable and highly conserved structures. Few of prokaryotic ubiquitin-like proteins was used as fusion tags except ThiS, which enhances the fusion expression, however, reduces the solubility and stability of the expressed peptides in E. coli. Hence, we investigated if MoaD, a conserved small sulfur carrier in prokaryotes with the similar structure of ubiquitin, could also be used as fusion tag in heterologous expression in E. coli. Fusion of MoaD to either end of EGFP enhanced the expression yield of EGFP with a similar efficacy of ThiS. However, the major parts of the fusion proteins were expressed in the aggregated form, which was associated with the retarded folding of EGFP, similar to ThiS fusions. Fusion of MoaD to insulin chain A or B did not boost their expression as efficiently as ThiS tag did, probably due to a less efficient aggregation of products. Interestingly, fusion of MoaD to the murine ribonuclease inhibitor enhanced protein expression by completely protecting the protein from intracellular degradation in contrast to ThiS fusion, which enhanced degradation of this unstable protein when expressed in E. coli. Prokaryotic ubiquitin-like protein MoaD can act as a fusion tag to promote the fusion expression with varying mechanisms, which enriches the arsenal of fusion tags in the category of insoluble expression.

  10. Directed Supramolecular Surface Assembly of SNAP-tag Fusion Proteins

    NARCIS (Netherlands)

    Uhlenheuer, D.A.; Wasserberg, D.; Haase, C.; Nguyen, Hoang D.; Schenkel, J.H.; Huskens, Jurriaan; Ravoo, B.J.; Jonkheijm, Pascal; Brunsveld, Luc

    2012-01-01

    Supramolecular assembly of proteins on surfaces and vesicles was investigated by site-selective incorporation of a supramolecular guest element on proteins. Fluorescent proteins were site-selectively labeled with bisadamantane by SNAP-tag technology. The assembly of the bisadamantane functionalized

  11. Immobilization of ferrocene-modified SNAP-fusion proteins

    NARCIS (Netherlands)

    Wasserberg, D.; Uhlenheuer, D.; Neirynck, P.; Neirynck, Pauline; Cabanas Danés, Jordi; Schenkel, J.H.; Ravoo, B.J.; An, Q.; Huskens, Jurriaan; Milroy, L.G.; Brunsveld, Luc; Jonkheijm, Pascal

    2013-01-01

    The supramolecular assembly of proteins on surfaces has been investigated via the site-selective incorporation of a supramolecular moiety on proteins. To this end, fluorescent proteins have been site-selectively labeled with ferrocenes, as supramolecular guest moieties, via SNAP-tag technology. The

  12. [The high expression of HPV31 and 52 L2 fusion protein in E. coli and detection of its immunogenicity].

    Science.gov (United States)

    Zhou, Ling; Ren, Jiao; Zhao, Li; Feng, Jing; Hao, Ming-Qiang; Tan, Wen-Jie; Ruan, Li; Qu, Peng-Peng; Tian, Hou-Wen

    2013-04-01

    To express HPV31 and 52 L2 fusion protein and detect its immunogenicity. According to the amino acid sequences of HPV31 and 52 L2 11-200AA published in the GenBank database, weartificially synthesized the HPV31 and 52 L2 fusion gene which was optimized according to Escherichia coli codon usage and encodes 11-200 amino acid of HPV31 and HPV52 L2, then cloned it into pET-9a vector. The HPV31 and 52 L2 fusion protein was expressed in Prokaryotic expression system and the mice were immunized with the fusion protein after purification. The immunogenicity was characterized in vaccinated mice. HPV31 and 52 L2 fusion protein was highly expressed in E. coli, the amount of fusion protein is nearly 20% of the total bacterial protein. The purified fusion protein with aluminum adjuvant could induce specific high titer of IgG antibodies detected by ELISA, and also induce the neutralizing antibodies against pseudovirus of HPV31 and HPV52 and cross-neutralizing antibodies against pseudovirus of HPV45, 58, 16, 18. HPV31 and 52 L2 fusion protein could induce neutralizing and cross-neutralizing antibodies against HPV pseudovirus. It provides laboratory basis for development of HPV L2 protein vaccine.

  13. Inhibition of CRM1-mediated nuclear export of transcription factors by leukemogenic NUP98 fusion proteins.

    Science.gov (United States)

    Takeda, Akiko; Sarma, Nayan J; Abdul-Nabi, Anmaar M; Yaseen, Nabeel R

    2010-05-21

    NUP98 is a nucleoporin that plays complex roles in the nucleocytoplasmic trafficking of macromolecules. Rearrangements of the NUP98 gene in human leukemia result in the expression of numerous fusion oncoproteins whose effect on nucleocytoplasmic trafficking is poorly understood. The present study was undertaken to determine the effects of leukemogenic NUP98 fusion proteins on CRM1-mediated nuclear export. NUP98-HOXA9, a prototypic NUP98 fusion, inhibited the nuclear export of two known CRM1 substrates: mutated cytoplasmic nucleophosmin and HIV-1 Rev. In vitro binding assays revealed that NUP98-HOXA9 binds CRM1 through the FG repeat motif in a Ran-GTP-dependent manner similar to but stronger than the interaction between CRM1 and its export substrates. Two NUP98 fusions, NUP98-HOXA9 and NUP98-DDX10, whose fusion partners are structurally and functionally unrelated, interacted with endogenous CRM1 in myeloid cells as shown by co-immunoprecipitation. These leukemogenic NUP98 fusion proteins interacted with CRM1, Ran, and the nucleoporin NUP214 in a manner fundamentally different from that of wild-type NUP98. NUP98-HOXA9 and NUP98-DDX10 formed characteristic aggregates within the nuclei of a myeloid cell line and primary human CD34+ cells and caused aberrant localization of CRM1 to these aggregates. These NUP98 fusions caused nuclear accumulation of two transcription factors, NFAT and NFkappaB, that are regulated by CRM1-mediated export. The nuclear entrapment of NFAT and NFkappaB correlated with enhanced transcription from promoters responsive to these transcription factors. Taken together, the results suggest a new mechanism by which NUP98 fusions dysregulate transcription and cause leukemia, namely, inhibition of CRM1-mediated nuclear export with aberrant nuclear retention of transcriptional regulators.

  14. rDNA Mediated Bioconjugates: Fusion Proteins and their Intended Use in Medicine.

    Science.gov (United States)

    Kaya-Ozsan, Ayse Goksu; Oner, Ayse Filiz

    2017-01-01

    Protein bioconjugates can be synthesized by using chemical reactions, enzymatic reactions or genetic engineering technologies. Naturally occurred protein fusion event is used on purpose in the development of better biopharmaceuticals by applying genetic engineering methodologies. This review will mainly focus on the types of fusion proteins produced with the use of recombinant DNA technology, by combining genes or parts of genes from the same or different organisms, in order to be used in pharmaceutical applications for several purposes. Main concerns for the development of better biopharmaceuticals include quality, efficacy, safety, immunogenicity and toxicity issues. Extending half-life of the drug to increase patient compliance, targeting the drugs to reduce toxicity, improving the manufacturing environment to reduce the costs and revealing protein interaction technologies to find novel and superior drugs are the main aims of fusion protein production. Here, related tags and examples of fusion methods for different purposes will be explained precisely. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  15. Construction and expression of recombinant fusion protein of thioredoxin-ApoO.

    Science.gov (United States)

    Wu, Chenlu; Zhao, Shuiping; Yu, Bilian; Xiong, Dan

    2011-02-01

    To construct human apolipoprotein O (apolipoprotein O, ApoO) expression vector and obtain recombinant fusion protein thioredoxin (Trx)-ApoO by pET prokaryotic expression system. The ApoO gene fragment from the human liver cDNA library was amplified by PCR. The resulting product was cloned into pET-32a(+) vector and sequenced. The confirmed cDNA was cloned into plasmid E.coli DH10B and then transformed into E.coli BL 21 (DE3) where it was induced to express protein by isopropyl β-D-1-thiogalactopyranoside (IPTG). The fusion protein was purified by Ni-NTA resin. The ApoO gene was cloned by PCR and a 519 bp DNA fragment was shown on the agarose electrophoresis. The cloned gene was sequenced and demonstrated to have the same sequence as that of human ApoO gene in GenBank which justified a successful construction of recombinant plasmid. ApoO cDNA gene fragment was induced by IPTG, and a 34 kD recombinant fusion protein Trx-ApoO was tested on sodium dodecyl sulfate polyacrylamide (SDS-PAGE). Human ApoO gene is successfully cloned and its recombinant fusion protein Trx-ApoO is expressed.

  16. Design and characterization of novel recombinant listeriolysin O-protamine fusion proteins for enhanced gene delivery.

    Science.gov (United States)

    Kim, Na Hyung; Provoda, Chester; Lee, Kyung-Dall

    2015-02-02

    To improve the efficiency of gene delivery for effective gene therapy, it is essential that the vector carries functional components that can promote overcoming barriers in various steps leading to the transport of DNA from extracellular to ultimately nuclear compartment. In this study, we designed genetically engineered fusion proteins as a platform to incorporate multiple functionalities in one chimeric protein. Prototypes of such a chimera tested here contain two domains: one that binds to DNA; the other that can facilitate endosomal escape of DNA. The fusion proteins are composed of listeriolysin O (LLO), the endosomolytic pore-forming protein from Listeria monocytogenes, and a 22 amino acid sequence of the DNA-condensing polypeptide protamine (PN), singly or as a pair: LLO-PN and LLO-PNPN. We demonstrate dramatic enhancement of the gene delivery efficiency of protamine-condensed DNA upon incorporation of a small amount of LLO-PN fusion protein and further improvement with LLO-PNPN in vitro using cultured cells. Additionally, the association of anionic liposomes with cationic LLO-PNPN/protamine/DNA complexes, yielding a net negative surface charge, resulted in better in vitro transfection efficiency in the presence of serum. An initial, small set of data in mice indicated that the observed enhancement in gene expression could also be applicable to in vivo gene delivery. This study suggests that incorporation of a recombinant fusion protein with multiple functional components, such as LLO-protamine fusion protein, in a nonviral vector is a promising strategy for various nonviral gene delivery systems.

  17. Genetically engineered endostatin-lidamycin fusion proteins effectively inhibit tumor growth and metastasis

    International Nuclear Information System (INIS)

    Jiang, Wen-guo; Zhen, Yong-su; Lu, Xin-an; Shang, Bo-yang; Fu, Yan; Zhang, Sheng-hua; Zhou, Daifu; Li, Liang; Li, Yi; Luo, Yongzhang

    2013-01-01

    Endostatin (ES) inhibits endothelial cell proliferation, migration, invasion, and tube formation. It also shows antiangiogenesis and antitumor activities in several animal models. Endostatin specifically targets tumor vasculature to block tumor growth. Lidamycin (LDM), which consists of an active enediyne chromophore (AE) and a non-covalently bound apo-protein (LDP), is a member of chromoprotein family of antitumor antibiotics with extremely potent cytotoxicity to cancer cells. Therefore, we reasoned that endostatin-lidamycin (ES-LDM) fusion proteins upon energizing with enediyne chromophore may obtain the combined capability targeting tumor vasculature and tumor cell by respective ES and LDM moiety. In this study, we designed and obtained two new endostatin-based fusion proteins, endostatin-LDP (ES-LDP) and LDP-endostatin (LDP-ES). In vitro, the antiangiogenic effect of fusion proteins was determined by the wound healing assay and tube formation assay and the cytotoxicity of their enediyne-energized analogs was evaluated by CCK-8 assay. Tissue microarray was used to analyze the binding affinity of LDP, ES or ES-LDP with specimens of human lung tissue and lung tumor. The in vivo efficacy of the fusion proteins was evaluated with human lung carcinoma PG-BE1 xenograft and the experimental metastasis model of 4T1-luc breast cancer. ES-LDP and LDP-ES disrupted the formation of endothelial tube structures and inhibited endothelial cell migration. Evidently, ES-LDP accumulated in the tumor and suppressed tumor growth and metastasis. ES-LDP and ES show higher binding capability than LDP to lung carcinoma; in addition, ES-LDP and ES share similar binding capability. Furthermore, the enediyne-energized fusion protein ES-LDP-AE demonstrated significant efficacy against lung carcinoma xenograft in athymic mice. The ES-based fusion protein therapy provides some fundamental information for further drug development. Targeting both tumor vasculature and tumor cells by endostatin

  18. Integrin αvβ1 Modulation Affects Subtype B Avian Metapneumovirus Fusion Protein-mediated Cell-Cell Fusion and Virus Infection.

    Science.gov (United States)

    Yun, Bing-Ling; Guan, Xiao-Lu; Liu, Yong-Zhen; Zhang, Yao; Wang, Yong-Qiang; Qi, Xiao-Le; Cui, Hong-Yu; Liu, Chang-Jun; Zhang, Yan-Ping; Gao, Hong-Lei; Gao, Li; Li, Kai; Gao, Yu-Long; Wang, Xiao-Mei

    2016-07-08

    Avian metapneumovirus (aMPV) fusion (F) protein mediates virus-cell membrane fusion to initiate viral infection, which requires F protein binding to its receptor(s) on the host cell surface. However, the receptor(s) for aMPV F protein is still not identified. All known subtype B aMPV (aMPV/B) F proteins contain a conserved Arg-Asp-Asp (RDD) motif, suggesting that the aMPV/B F protein may mediate membrane fusion via the binding of RDD to integrin. When blocked with integrin-specific peptides, aMPV/B F protein fusogenicity and viral replication were significantly reduced. Specifically we identified integrin αv and/or β1-mediated F protein fusogenicity and viral replication using antibody blocking, small interfering RNAs (siRNAs) knockdown, and overexpression. Additionally, overexpression of integrin αv and β1 in aMPV/B non-permissive cells conferred aMPV/B F protein binding and aMPV/B infection. When RDD was altered to RAE (Arg-Ala-Glu), aMPV/B F protein binding and fusogenic activity were profoundly impaired. These results suggest that integrin αvβ1 is a functional receptor for aMPV/B F protein-mediated membrane fusion and virus infection, which will provide new insights on the fusogenic mechanism and pathogenesis of aMPV. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Integrin αvβ1 Modulation Affects Subtype B Avian Metapneumovirus Fusion Protein-mediated Cell-Cell Fusion and Virus Infection*

    Science.gov (United States)

    Yun, Bing-Ling; Guan, Xiao-Lu; Liu, Yong-Zhen; Zhang, Yao; Wang, Yong-Qiang; Qi, Xiao-Le; Cui, Hong-Yu; Liu, Chang-Jun; Zhang, Yan-Ping; Gao, Hong-Lei; Gao, Li; Li, Kai; Gao, Yu-Long; Wang, Xiao-Mei

    2016-01-01

    Avian metapneumovirus (aMPV) fusion (F) protein mediates virus-cell membrane fusion to initiate viral infection, which requires F protein binding to its receptor(s) on the host cell surface. However, the receptor(s) for aMPV F protein is still not identified. All known subtype B aMPV (aMPV/B) F proteins contain a conserved Arg-Asp-Asp (RDD) motif, suggesting that the aMPV/B F protein may mediate membrane fusion via the binding of RDD to integrin. When blocked with integrin-specific peptides, aMPV/B F protein fusogenicity and viral replication were significantly reduced. Specifically we identified integrin αv and/or β1-mediated F protein fusogenicity and viral replication using antibody blocking, small interfering RNAs (siRNAs) knockdown, and overexpression. Additionally, overexpression of integrin αv and β1 in aMPV/B non-permissive cells conferred aMPV/B F protein binding and aMPV/B infection. When RDD was altered to RAE (Arg-Ala-Glu), aMPV/B F protein binding and fusogenic activity were profoundly impaired. These results suggest that integrin αvβ1 is a functional receptor for aMPV/B F protein-mediated membrane fusion and virus infection, which will provide new insights on the fusogenic mechanism and pathogenesis of aMPV. PMID:27226547

  20. A protein coevolution method uncovers critical features of the Hepatitis C Virus fusion mechanism

    Science.gov (United States)

    Douam, Florian; Mancip, Jimmy; Mailly, Laurent; Montserret, Roland; Ding, Qiang; Verhoeyen, Els; Baumert, Thomas F.; Ploss, Alexander; Carbone, Alessandra

    2018-01-01

    Amino-acid coevolution can be referred to mutational compensatory patterns preserving the function of a protein. Viral envelope glycoproteins, which mediate entry of enveloped viruses into their host cells, are shaped by coevolution signals that confer to viruses the plasticity to evade neutralizing antibodies without altering viral entry mechanisms. The functions and structures of the two envelope glycoproteins of the Hepatitis C Virus (HCV), E1 and E2, are poorly described. Especially, how these two proteins mediate the HCV fusion process between the viral and the cell membrane remains elusive. Here, as a proof of concept, we aimed to take advantage of an original coevolution method recently developed to shed light on the HCV fusion mechanism. When first applied to the well-characterized Dengue Virus (DENV) envelope glycoproteins, coevolution analysis was able to predict important structural features and rearrangements of these viral protein complexes. When applied to HCV E1E2, computational coevolution analysis predicted that E1 and E2 refold interdependently during fusion through rearrangements of the E2 Back Layer (BL). Consistently, a soluble BL-derived polypeptide inhibited HCV infection of hepatoma cell lines, primary human hepatocytes and humanized liver mice. We showed that this polypeptide specifically inhibited HCV fusogenic rearrangements, hence supporting the critical role of this domain during HCV fusion. By combining coevolution analysis and in vitro assays, we also uncovered functionally-significant coevolving signals between E1 and E2 BL/Stem regions that govern HCV fusion, demonstrating the accuracy of our coevolution predictions. Altogether, our work shed light on important structural features of the HCV fusion mechanism and contributes to advance our functional understanding of this process. This study also provides an important proof of concept that coevolution can be employed to explore viral protein mediated-processes, and can guide the

  1. Renal cold storage followed by transplantation impairs expression of key mitochondrial fission and fusion proteins.

    Directory of Open Access Journals (Sweden)

    Nirmala Parajuli

    Full Text Available The majority of transplanted kidneys are procured from deceased donors which all require exposure to cold storage (CS for successful transplantation. Unfortunately, this CS leads to renal and mitochondrial damage but, specific mitochondrial targets affected by CS remain largely unknown. The goal of this study is to determine whether pathways involved with mitochondrial fusion or fission, are disrupted during renal CS.Male Lewis rat kidneys were exposed to cold storage (CS alone or cold storage combined with transplantation (CS/Tx. To compare effects induced by CS, kidney transplantation without CS exposure (autotransplantation; ATx was also used. Mitochondrial function was assessed using high resolution respirometry. Expression of mitochondrial fusion and fission proteins were monitored using Western blot analysis.CS alone (no Tx reduced respiratory complex I and II activities along with reduced expression of the primary mitochondrial fission protein, dynamin related protein (DRP1, induced loss of the long form of Optic Atrophy Protein (OPA1, and altered the mitochondrial protease, OMA1, which regulates OPA1 processing. CS followed by Tx (CS/Tx reduced complex I, II, and III activities, and induced a profound loss of the long and short forms of OPA1, mitofusin 1 (MFN1, and mitofusin 2 (MFN2 which all control mitochondrial fusion. In addition, expression of DRP1, along with its primary receptor protein, mitochondrial fission factor (MFF, were also reduced after CS/Tx. Interestingly, CS/Tx lead to aberrant higher molecular weight OMA1 aggregate expression.Our results suggest that CS appears to involve activation of the OMA1, which could be a key player in proteolysis of the fusion and fission protein machinery following transplantation. These findings raise the possibility that impaired mitochondrial fission and fusion may be unrecognized contributors to CS induced mitochondrial injury and compromised renal graft function after transplantation.

  2. Enhanced SUMOylation of proteins containing a SUMO-interacting motif by SUMO-Ubc9 fusion

    International Nuclear Information System (INIS)

    Kim, Eui Tae; Kim, Kyeong Kyu; Matunis, Mike J.; Ahn, Jin-Hyun

    2009-01-01

    Identifying new targets for SUMO and understanding the function of protein SUMOylation are largely limited by low level of SUMOylation. It was found recently that Ubc9, the SUMO E2 conjugating enzyme, is covalently modified by SUMO at a lysine 14 in the N-terminal alpha helix, and that SUMO-modified Ubc9 has enhanced conjugation activity for certain target proteins containing a SUMO-interacting motif (SIM). Here, we show that, compared to intact Ubc9, the SUMO-Ubc9 fusion protein has higher conjugating activity for SIM-containing targets such as Sp100 and human cytomegalovirus IE2. Assays using an IE2 SIM mutant revealed the requirement of SIM for the enhanced IE2 SUMOylation by SUMO-Ubc9. In pull-down assays with cell extracts, the SUMO-Ubc9 fusion protein bound to more diverse cellular proteins and interacted with some SIM-containing proteins with higher affinities than Ubc9. Therefore, the devised SUMO-Ubc9 fusion will be useful for identifying SIM-containing SUMO targets and producing SUMO-modified proteins.

  3. SUMO fusion technology for enhanced protein production in prokaryotic and eukaryotic expression systems.

    Science.gov (United States)

    Panavas, Tadas; Sanders, Carsten; Butt, Tauseef R

    2009-01-01

    In eukaryotic cells, the reversible attachment of small ubiquitin-like modifier (SUMO) protein is a post-translational modification that has been demonstrated to play an important role in various cellular processes. Moreover, it has been found that SUMO as an N-terminal fusion partner enhances functional protein production in prokaryotic and eukaryotic expression systems, based upon significantly improved protein stability and solubility. Following the expression and purification of the fusion protein, the SUMO-tag can be cleaved by specific (SUMO) proteases via their endopeptidase activity in vitro to generate the desired N-terminus of the released protein partner. In addition to its physiological relevance in eukaryotes, SUMO can, thus, be used as a powerful biotechnological tool for protein expression in prokaryotic and eukaryotic cell systems.In this chapter, we will describe the construction of a fusion protein with the SUMO-tag, its expression in Escherichia coli, and its purification followed by the removal of the SUMO-tag by a SUMO-specific protease in vitro.

  4. Enhanced SUMOylation of proteins containing a SUMO-interacting motif by SUMO-Ubc9 fusion

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eui Tae; Kim, Kyeong Kyu [Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Cheoncheondong Jangangu, Suwon, Gyeonggido 440-746 (Korea, Republic of); Matunis, Mike J. [Department of Biochemistry and Molecular Biology, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD (United States); Ahn, Jin-Hyun, E-mail: jahn@med.skku.ac.kr [Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Cheoncheondong Jangangu, Suwon, Gyeonggido 440-746 (Korea, Republic of)

    2009-10-09

    Identifying new targets for SUMO and understanding the function of protein SUMOylation are largely limited by low level of SUMOylation. It was found recently that Ubc9, the SUMO E2 conjugating enzyme, is covalently modified by SUMO at a lysine 14 in the N-terminal alpha helix, and that SUMO-modified Ubc9 has enhanced conjugation activity for certain target proteins containing a SUMO-interacting motif (SIM). Here, we show that, compared to intact Ubc9, the SUMO-Ubc9 fusion protein has higher conjugating activity for SIM-containing targets such as Sp100 and human cytomegalovirus IE2. Assays using an IE2 SIM mutant revealed the requirement of SIM for the enhanced IE2 SUMOylation by SUMO-Ubc9. In pull-down assays with cell extracts, the SUMO-Ubc9 fusion protein bound to more diverse cellular proteins and interacted with some SIM-containing proteins with higher affinities than Ubc9. Therefore, the devised SUMO-Ubc9 fusion will be useful for identifying SIM-containing SUMO targets and producing SUMO-modified proteins.

  5. Protein fusion tags for efficient expression and purification of recombinant proteins in the periplasmic space of E. coli.

    Science.gov (United States)

    Malik, Ajamaluddin

    2016-06-01

    Disulfide bonds occurred in majority of secreted protein. Formation of correct disulfide bonds are must for achieving native conformation, solubility and activity. Production of recombinant proteins containing disulfide bond for therapeutic, diagnostic and various other purposes is a challenging task of research. Production of such proteins in the reducing cytosolic compartment of E. coli usually ends up in inclusion bodies formation. Refolding of inclusion bodies can be difficult, time and labor consuming and uneconomical. Translocation of these proteins into the oxidative periplasmic compartment provides correct environment to undergo proper disulfide bonds formation and thus achieving native conformation. However, not all proteins can be efficiently translocated to the periplasm with the help of bacterial signal peptides. Therefore, fusion to a small well-folded and stable periplasmic protein is more promising for periplasmic production of disulfide bonded proteins. In the past decades, several full-length proteins or domains were used for enhancing translocation and solubility. Here, protein fusion tags that significantly increase the yields of target proteins in the periplasmic space are reviewed.

  6. Quantitative detection of fusion protein rIFN-ß-HSA by a sandwich ...

    African Journals Online (AJOL)

    Abstract. A method that allowed detection and quantification of recombinant fusion protein rIFN-ß-HSA in complex mixtures and fermentation media was described. The method was based on a double antibody sandwich ELISA, which was developed by using an anti-IFN-ß monoclonal antibody as capture antibody and an ...

  7. Human antibodies and fusion proteins as HIV-1 therapeutic | NCI Technology Transfer Center | TTC

    Science.gov (United States)

    Available for licensing from the NCI are novel human anti-HIV-1 domain antibodies and their fusion proteins for anti-HIV-1 antibodies and anti-retroviral as therapeutics and/or preventatives for infection by different HIV-1 strains.

  8. Quantitative detection of fusion protein rIFN-β-HSA by a sandwich ...

    African Journals Online (AJOL)

    user

    2011-02-14

    Feb 14, 2011 ... A method that allowed detection and quantification of recombinant fusion protein rIFN-β-HSA in complex mixtures and ... practical working range was estimated to be 21.01 ng/ml to 672.50 ng/ml and the limit of detection was. 13.88 ng/ml. ..... avidin labeling system, enzyme-linked radioactive assay, etc.

  9. Membrane fusion is induced by a distinct peptide sequence of the sea urchin fertilization protein bindin

    NARCIS (Netherlands)

    Ulrich, AS; Glabe, CG; Hoekstra, D

    1998-01-01

    Fertilization in the sea urchin is mediated by the membrane-associated acrosomal protein bindin, which plays a key role in the adhesion and fusion between sperm and egg. We have investigated the structure/function relationship of an 18-amino acid peptide fragment "B18," which represents the minimal

  10. Anti-Diabetic Effects of CTB-APSL Fusion Protein in Type 2 Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Yunlong Liu

    2014-03-01

    Full Text Available To determine whether cholera toxin B subunit and active peptide from shark liver (CTB-APSL fusion protein plays a role in treatment of type 2 diabetic mice, the CTB-APSL gene was cloned and expressed in silkworm (Bombyx mori baculovirus expression vector system (BEVS, then the fusion protein was orally administrated at a dose of 100 mg/kg for five weeks in diabetic mice. The results demonstrated that the oral administration of CTB-APSL fusion protein can effectively reduce the levels of both fasting blood glucose (FBG and glycosylated hemoglobin (GHb, promote insulin secretion and improve insulin resistance, significantly improve lipid metabolism, reduce triglycerides (TG, total cholesterol (TC and low density lipoprotein (LDL levels and increase high density lipoprotein (HDL levels, as well as effectively improve the inflammatory response of type 2 diabetic mice through the reduction of the levels of inflammatory cytokines tumor necrosis factor-α (TNF-α and interleukin-6 (IL-6. Histopathology shows that the fusion protein can significantly repair damaged pancreatic tissue in type 2 diabetic mice, significantly improve hepatic steatosis and hepatic cell cloudy swelling, reduce the content of lipid droplets in type 2 diabetic mice, effectively inhibit renal interstitial inflammatory cells invasion and improve renal tubular epithelial cell nucleus pyknosis, thus providing an experimental basis for the development of a new type of oral therapy for type 2 diabetes.

  11. Low Resolution Structure of RAR1-GST-Tag Fusion Protein in Solution

    International Nuclear Information System (INIS)

    Taube, M.; Kozak, M.; Jarmolowski, A.

    2010-01-01

    RAR1 is a protein required for resistance mediated by many R genes and function upstream of signaling pathways leading to H 2 O 2 accumulation. The structure and conformation of RAR1-GST-Tag fusion protein from barley (Hordeum vulgare) in solution was studied by the small angle scattering of synchrotron radiation. It was found that the dimer of RAR1-GST-Tag protein is characterized in solution by radius of gyration R G = 6.19 nm and maximal intramolecular vector D max = 23 nm. On the basis of the small angle scattering of synchrotron radiation SAXS data two bead models obtained by ab initio modeling are proposed. Both models show elongated conformations. We also concluded that molecules of fusion protein form: dimers in solution via interaction of GST domains. (authors)

  12. Transgenic Carrot Expressing Fusion Protein Comprising M. tuberculosis Antigens Induces Immune Response in Mice

    Directory of Open Access Journals (Sweden)

    Natalia V. Permyakova

    2015-01-01

    Full Text Available Tuberculosis remains one of the major infectious diseases, which continues to pose a major global health problem. Transgenic plants may serve as bioreactors to produce heterologous proteins including antibodies, antigens, and hormones. In the present study, a genetic construct has been designed that comprises the Mycobacterium tuberculosis genes cfp10, esat6 and dIFN gene, which encode deltaferon, a recombinant analog of the human γ-interferon designed for expression in plant tissues. This construct was transferred to the carrot (Daucus carota L. genome by Agrobacterium-mediated transformation. This study demonstrates that the fusion protein CFP10-ESAT6-dIFN is synthesized in the transgenic carrot storage roots. The protein is able to induce both humoral and cell-mediated immune responses in laboratory animals (mice when administered either orally or by injection. It should be emphasized that M. tuberculosis antigens contained in the fusion protein have no cytotoxic effect on peripheral blood mononuclear cells.

  13. Rational design of highly potent HIV-1 fusion inhibitory proteins: Implication for developing antiviral therapeutics

    International Nuclear Information System (INIS)

    Ni Ling; Gao, George F.; Tien Po

    2005-01-01

    Recombinant protein containing one heptad-repeat 1 (HR1) segment and one HR2 segment of the HIV-1 gp41 (HR1-HR2) has been shown to fold into thermally stable six-helix bundle, representing the fusogenic core of gp41. In this study, we have used the fusogenic core as a scaffold to design HIV-1 fusion inhibitory proteins by linking another HR1 to the C terminus of HR1-HR2 (HR121) or additional HR2 to the N terminus of HR1-HR2 (HR212). Both recombinant proteins could be abundantly and solubly expressed and easily purified, exhibiting high stability and potent inhibitory activity on HIV-1 fusion with IC 50 values of 16.2 ± 2.8 and 2.8 ± 0.63 nM, respectively. These suggest that these rationally designed proteins can be further developed as novel anti-HIV-1 therapeutics

  14. Melittin-MIL-2 fusion protein as a candidate for cancer immunotherapy.

    Science.gov (United States)

    Liu, Mingjun; Wang, Haitao; Liu, Linjie; Wang, Bin; Sun, Guirong

    2016-06-01

    Cytokine fusion protein that modulates the immune response holds great potential for cancer immunotherapy. IL-2 is an effective treatment against advanced cancers. However, the therapeutic efficacy of IL-2 is limited by severe systemic toxicity. Several mutants recombinant IL-2 can increase antitumor activity and minimize systemic toxicity. Melittin is an attractive anticancer candidate because of its wide-spectrum lytic properties. We previously generated a bifunctional fusion protein melittin-MIL-2, composed of melittin and a mutant IL-2. The melittin-MIL-2 inhibited the growth of human ovarian cancer SKOV3 cells in vitro and in vivo tumor growth. However, whether this antitumor effect could also be used in cancer immunotherapy was unknown. To assess its cancer immunotherapy potential, we further investigated its more effective antitumor immune response and antitumor effect against cancers of different tissue origins in vitro and in vivo. The specific IL-2 activity of the melittin-MIL-2 fusion protein was tested on the cytokine growth dependent cell line CTLL-2. The cytolytic activity was detected by standard 4-h (51)Cr-release assays. PBMC stimulation in response to the melittin-MIL-2 was determined by IFN-γ release assay. We observed the cancer cell proliferation of different tissue origins by MTT assay. The ability of melittin-MIL-2 to inhibit tumor growth in vivo was evaluated by using human liver (SMMC-7721 cancer cells), lung (A549 cancer cells) and ovarian (SKOV3 cancer cells) cancer xenograft models. To assess the immunity within the tumor microenvironment, the level of some cytokines including IFN-γ, TNF-α, IL-12 and IL-4 was analyzed by ELISA. We injected the MDA-MB-231 cells and the melittin-MIL-2 into mice, and the anti-metastatic effect was examined by counting nodules in the lung. The melittin-MIL-2 was more effective in inducing T cell and NK-cell cytotoxicity. The fusion protein significantly increased IFN-γ production in PBMCs. In vitro, the

  15. Targeted Delivery of siRNA into Breast Cancer Cells via Phage Fusion Proteins

    OpenAIRE

    Bedi, Deepa; Gillespie, James W; Petrenko, Vasily A.; Ebner, Andreas; Leitner, Michael; Hinterdorfer, Peter; Petrenko, Valery A.

    2013-01-01

    Nucleic acids including antisense oligonucleotides, small interfering RNA (siRNA), aptamers and rybozymes, emerged as versatile therapeutics due to their ability to interfere in a well-planned manner with the flow of genetic information from DNA to protein. However, a systemic use of NAs is hindered by their instability in physiological liquids and inability of intracellular accumulation in the site of action. We first evaluated the potential of cancer specific phage fusion proteins as target...

  16. C-E1 fusion protein synthesized by rubella virus DI RNAs maintained during serial passage

    International Nuclear Information System (INIS)

    Tzeng, W.-P.; Frey, Teryl K.

    2006-01-01

    Rubella virus (RUB) replicons are derivatives of the RUB infectious cDNA clone that retain the nonstructural open reading frame (NS-ORF) that encodes the replicase proteins but not the structural protein ORF (SP-ORF) that encodes the virion proteins. RUB defective interfering (DI) RNAs contain deletions within the SP-ORF and thus resemble replicons. DI RNAs often retain the 5' end of the capsid protein (C) gene that has been shown to modulate virus-specific RNA synthesis. However, when replicons either with or without the C gene were passaged serially in the presence of wt RUB as a source of the virion proteins, it was found that neither replicon was maintained and DI RNAs were generated. The majority DI RNA species contained in-frame deletions in the SP-ORF leading to a fusion between the 5' end of the C gene and the 3' end of the E1 glycoprotein gene. DI infectious cDNA clones were constructed and transcripts from these DI infectious cDNA clones were maintained during serial passage with wt RUB. The C-E1 fusion protein encoded by the DI RNAs was synthesized and was required for maintenance of the DI RNA during serial passage. This is the first report of a functional novel gene product resulting from deletion during DI RNA generation. Thus far, the role of the C-E1 fusion protein in maintenance of DI RNAs during serial passage remained elusive as it was found that the fusion protein diminished rather than enhanced DI RNA synthesis and was not incorporated into virus particles

  17. Recombinant chymosin used for exact and complete removal of a prochymosin derived fusion tag releasing intact native target protein

    DEFF Research Database (Denmark)

    Justesen, Sune; Lamberth, Kasper; Nielsen, Lise-Lotte B

    2009-01-01

    Fusion tags add desirable properties to recombinant proteins, but they are not necessarily acceptable in the final products. Ideally, fusion tags should be removed releasing the intact native protein with no trace of the tag. Unique endoproteinases with the ability to cleave outside their own...... recognition sequence can potentially cleave at the boundary of any native protein. Chymosin was recently shown to cleave a pro-chymosin derived fusion tag releasing native target proteins. In our hands, however, not all proteins are chymosin-resistant under the acidic cleavage conditions (pH 4.5) used...... in this system. Here, we have modified the pro-chymosin fusion tag and demonstrated that chymosin can remove this tag at more neutral pH (pH 6.2); conditions, that are less prone to compromise the integrity of target proteins. Chymosin was successfully used to produce intact native target protein both...

  18. Matrix protein 2 of influenza A virus blocks autophagosome fusion with lysosomes

    DEFF Research Database (Denmark)

    Gannagé, Monique; Dormann, Dorothee; Albrecht, Randy

    2009-01-01

    demonstrate that influenza A virus inhibits macroautophagy, a cellular process known to be manipulated by diverse pathogens. Influenza A virus infection causes accumulation of autophagosomes by blocking their fusion with lysosomes, and one viral protein, matrix protein 2, is necessary and sufficient...... for this inhibition of autophagosome degradation. Macroautophagy inhibition by matrix protein 2 compromises survival of influenza virus-infected cells but does not influence viral replication. We propose that influenza A virus, which also encodes proapoptotic proteins, is able to determine the death of its host cell...

  19. A fluorescent cassette-based strategy for engineering multiple domain fusion proteins

    Directory of Open Access Journals (Sweden)

    Khorchid Ahmad

    2003-07-01

    Full Text Available Abstract Background The engineering of fusion proteins has become increasingly important and most recently has formed the basis of many biosensors, protein purification systems, and classes of new drugs. Currently, most fusion proteins consist of three or fewer domains, however, more sophisticated designs could easily involve three or more domains. Using traditional subcloning strategies, this requires micromanagement of restriction enzymes sites that results in complex workaround solutions, if any at all. Results Therefore, to aid in the efficient construction of fusion proteins involving multiple domains, we have created a new expression vector that allows us to rapidly generate a library of cassettes. Cassettes have a standard vector structure based on four specific restriction endonuclease sites and using a subtle property of blunt or compatible cohesive end restriction enzymes, they can be fused in any order and number of times. Furthermore, the insertion of PCR products into our expression vector or the recombination of cassettes can be dramatically simplified by screening for the presence or absence of fluorescence. Conclusions Finally, the utility of this new strategy was demonstrated by the creation of basic cassettes for protein targeting to subcellular organelles and for protein purification using multiple affinity tags.

  20. Construction of a linker library with widely controllable flexibility for fusion protein design.

    Science.gov (United States)

    Li, Gang; Huang, Ziliang; Zhang, Chong; Dong, Bo-Jun; Guo, Ruo-Hai; Yue, Hong-Wei; Yan, Li-Tang; Xing, Xin-Hui

    2016-01-01

    Flexibility or rigidity of the linker between two fused proteins is an important parameter that affects the function of fusion proteins. In this study, we constructed a linker library with five elementary units based on the combination of the flexible (GGGGS) and the rigid (EAAAK) units. Molecular dynamics (MD) simulation showed that more rigid units in the linkers lead to more helical conformation and hydrogen bonds, and less distance fluctuation between the N- and C-termini of the linker. The diversity of linker flexibility of the linker library was then studied by fluorescence resonance energy transfer (FRET) of cyan fluorescent protein (CFP)-yellow fluorescent protein (YFP) fusion proteins, which showed that there is a wide range of distribution of the FRET efficiency. Dissipative particle dynamics (DPD) simulation of CFP-YFP with different linkers also gave identical results with that of FRET efficiency analysis, and we further found that the combination manner of the linker peptide had a remarkable effect on the orientation of CFP and YFP domains. Our studies demonstrated that the construction of the linker library with the widely controllable flexibility could provide appropriate linkers with the desirable characteristics to engineer the fusion proteins with the expected functions.

  1. Insertion of inter-domain linkers improves expression and bioactivity of Zygote arrest (Zar) fusion proteins.

    Science.gov (United States)

    Cook, Jonathan M; Charlesworth, Amanda

    2017-04-01

    Developmentally important proteins that are crucial for fertilization and embryogenesis are synthesized through highly regulated translation of maternal mRNA. The Zygote arrest proteins, Zar1 and Zar2, are crucial for embryogenesis and have been implicated in binding mRNA and repressing mRNA translation. To investigate Zar1 and Zar2, the full-length proteins had been fused to glutathione-S-transferase (GST) or MS2 protein tags with minimal inter-domain linkers derived from multiple cloning sites; however, these fusion proteins expressed poorly and/or lacked robust function. Here, we tested the effect of inserting additional linkers between the fusion domains. Three linkers were tested, each 17 amino acids long with different physical and chemical properties: flexible hydrophilic, rigid extended or rigid helical. In the presence of any of the three linkers, GST-Zar1 and GST-Zar2 had fewer breakdown products. Moreover, in the presence of any of the linkers, MS2-Zar1 was expressed to higher levels, and in dual luciferase tethered assays, both MS2-Zar1 and MS2-Zar2 repressed luciferase translation to a greater extent. These data suggest that for Zar fusion proteins, increasing the length of linkers, regardless of their physical or chemical properties, improves stability, expression and bioactivity. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Construction, expression, functional сharacterization and practical application of fusion protein SPA-ВAPmut

    Directory of Open Access Journals (Sweden)

    Gorbatiuk O. B.

    2013-01-01

    Full Text Available Aim. The creation of genetically engineered fusion protein SPA-BAPmut and its application as a secondary immunoreagent in immunoassays. Methods. Gene cloning, PCR, electrophoresis, DNA sequencing, bacteria cells culturing, protein expression and purification, ELISA, Western-blotting were used. Results. The DNA sequences encoding Staphylococcus aureus protein A (SPA and bacterial alkaline phosphatase with enhanced catalytic activity (BAPmut were used for construction of gene encoding fusion protein SPA-BAPmut that was expressed in the high-productive Escherichia coli system and obtained in a soluble form. Cultivation conditions to provide a high-level expression of SPA-ВAPmut (> 1 g/l were determined. The target protein was obtained with purity more than 95 % using ІМАХ method. SPA-ВAPmut is thermostable, and both parts of fusion protein (SPA and BAPmut retain their IgG binding and alkaline phosphatase activity for a long time. SPA-BAPmut was used as a substitute of secondary antibodies in immunoassays. As little as 5 ng of the antigen could be detected in Western blotting and 1 g/ml of IgG in ELISA. Conclusions. The possibility of using SPA-ВAPmut as universal secondary immunoreagent for different types of immunoassays was shown.

  3. Spatiotemporal dynamics of membrane remodeling and fusion proteins during endocytic transport.

    Science.gov (United States)

    Arlt, Henning; Auffarth, Kathrin; Kurre, Rainer; Lisse, Dominik; Piehler, Jacob; Ungermann, Christian

    2015-04-01

    Organelles of the endolysosomal system undergo multiple fission and fusion events to combine sorting of selected proteins to the vacuole with endosomal recycling. This sorting requires a consecutive remodeling of the organelle surface in the course of endosomal maturation. Here we dissect the remodeling and fusion machinery on endosomes during the process of endocytosis. We traced selected GFP-tagged endosomal proteins relative to exogenously added fluorescently labeled α-factor on its way from the plasma membrane to the vacuole. Our data reveal that the machinery of endosomal fusion and ESCRT proteins has similar temporal localization on endosomes, whereas they precede the retromer cargo recognition complex. Neither deletion of retromer nor the fusion machinery with the vacuole affects this maturation process, although the kinetics seems to be delayed due to ESCRT deletion. Of importance, in strains lacking the active Rab7-like Ypt7 or the vacuolar SNARE fusion machinery, α-factor still proceeds to late endosomes with the same kinetics. This indicates that endosomal maturation is mainly controlled by the early endosomal fusion and remodeling machinery but not the downstream Rab Ypt7 or the SNARE machinery. Our data thus provide important further understanding of endosomal biogenesis in the context of cargo sorting. © 2015 Arlt et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  4. Autographa californica multiple nucleopolyhedrovirus GP64 protein: Analysis of domain I and V amino acid interactions and membrane fusion activity

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qianlong [State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Northwest Loess Plateau Crop Pest Management of Ministry of Agriculture, College of Plant Protection, Northwest A& F University, Yangling, Shaanxi 712100 (China); Blissard, Gary W. [Boyce Thompson Institute, Cornell University, Ithaca, NY 14853, United State (United States); Liu, Tong-Xian [State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Northwest Loess Plateau Crop Pest Management of Ministry of Agriculture, College of Plant Protection, Northwest A& F University, Yangling, Shaanxi 712100 (China); Li, Zhaofei, E-mail: zhaofeili73@outlook.com [State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Northwest Loess Plateau Crop Pest Management of Ministry of Agriculture, College of Plant Protection, Northwest A& F University, Yangling, Shaanxi 712100 (China)

    2016-01-15

    The Autographa californica multiple nucleopolyhedrovirus GP64 is a class III viral fusion protein. Although the post-fusion structure of GP64 has been solved, its pre-fusion structure and the detailed mechanism of conformational change are unknown. In GP64, domain V is predicted to interact with two domain I segments that flank fusion loop 2. To evaluate the significance of the amino acids involved in these interactions, we examined 24 amino acid positions that represent interacting and conserved residues within domains I and V. In several cases, substitution of a single amino acid involved in a predicted interaction disrupted membrane fusion activity, but no single amino acid pair appears to be absolutely required. We identified 4 critical residues in domain V (G438, W439, T452, and T456) that are important for membrane fusion, and two residues (G438 and W439) that appear to be important for formation or stability of the pre-fusion conformation of GP64. - Highlights: • The baculovirus envelope glycoprotein GP64 is a class III viral fusion protein. • The detailed mechanism of conformational change of GP64 is unknown. • We analyzed 24 positions that might stabilize the post-fusion structure of GP64. • We identified 4 residues in domain V that were critical for membrane fusion. • Two residues are critical for formation of the pre-fusion conformation of GP64.

  5. Autographa californica multiple nucleopolyhedrovirus GP64 protein: Analysis of domain I and V amino acid interactions and membrane fusion activity

    International Nuclear Information System (INIS)

    Yu, Qianlong; Blissard, Gary W.; Liu, Tong-Xian; Li, Zhaofei

    2016-01-01

    The Autographa californica multiple nucleopolyhedrovirus GP64 is a class III viral fusion protein. Although the post-fusion structure of GP64 has been solved, its pre-fusion structure and the detailed mechanism of conformational change are unknown. In GP64, domain V is predicted to interact with two domain I segments that flank fusion loop 2. To evaluate the significance of the amino acids involved in these interactions, we examined 24 amino acid positions that represent interacting and conserved residues within domains I and V. In several cases, substitution of a single amino acid involved in a predicted interaction disrupted membrane fusion activity, but no single amino acid pair appears to be absolutely required. We identified 4 critical residues in domain V (G438, W439, T452, and T456) that are important for membrane fusion, and two residues (G438 and W439) that appear to be important for formation or stability of the pre-fusion conformation of GP64. - Highlights: • The baculovirus envelope glycoprotein GP64 is a class III viral fusion protein. • The detailed mechanism of conformational change of GP64 is unknown. • We analyzed 24 positions that might stabilize the post-fusion structure of GP64. • We identified 4 residues in domain V that were critical for membrane fusion. • Two residues are critical for formation of the pre-fusion conformation of GP64.

  6. Quantitative imaging of green fluorescent protein in cultured cells: comparison of microscopic techniques, use in fusion proteins and detection limits.

    Science.gov (United States)

    Niswender, K D; Blackman, S M; Rohde, L; Magnuson, M A; Piston, D W

    1995-11-01

    To determine the application limits of green fluorescent protein (GFP) as a reporter gene or protein tag, we expressed GFP by itself and with fusion protein partners, and used three different imaging methods to identify GFP fluorescence. In conventional epifluorescence photomicroscopy, GFP expressed in cells could be distinguished as a bright green signal over a yellow-green autofluorescence background. In quantitative fluorescence microscopy, however, the GFP signal is contaminated by cellular autofluorescence. Improved separation of GFP signal from HeLa cell autofluorescence was achieved by the combination of confocal scanning laser microscopy using 488-nm excitation, a rapid cut-on dichroic mirror and a narrow-bandpass emission filter. Two-photon excitation of GFP fluorescence at the equivalent of approximately 390 nm provided better absorption than did 488-nm excitation. This resulted in increased signal/background but also generated a different autofluorescence pattern and appeared to increase GFP photobleaching. Fluorescence spectra similar to those of GFP alone were observed when GFP was expressed as a fusion protein either with glutathione-S-transferase (GST) or with glucokinase. Furthermore, purified GST.GFP fusion protein displayed an extinction coefficient and quantum yield consistent with values previously reported for GFP alone. In HeLa cells, the cytoplasmic GFP concentration must be greater than approximately 1 microM to allow quantifiable discrimination over autofluorescence. However, lower expression levels may be detectable if GFP is targeted to discrete subcellular compartments, such as the plasma membrane, organelles or nucleus.

  7. Baculoviral polyhedrin-Bacillus thuringiensis toxin fusion protein: a protein-based bio-insecticide expressed in Escherichia coli.

    Science.gov (United States)

    Seo, Jeong Hyun; Yeo, Joo Sang; Cha, Hyung Joon

    2005-10-20

    Previously, we found that baculoviral polyhedrin (Polh) used as a fusion partner for recombinant expression in Escherichia coli showed almost the same characteristics (rapid solubilization under alkaline conditions and specific degradation by specific alkaline proteases in insect midgut) as the native baculoviral Polh, and formed easily isolatable inclusion bodies. Here, Polh derived from the Autographa californica nuclear polyhedrosis virus (AcNPV) was fused with a Bacillus thuringiensis (Bt) toxin protein (truncated Cry1Ac having toxin region as a model Bt toxin) for the novel generation of a new bio-insecticide. The Polh-Cry1Ac fusion protein (approximately 99 kDa) was highly expressed (3.6-fold induction as compared to E. coli-derived single Cry1Ac (approximately 68 kDa)) as an insoluble inclusion body fraction in E. coli. Trypsin and alpha-chymotrypsin, which have similar properties to the insect midgut alkaline proteases, rapidly degraded the Polh portion in vitro, leaving only the toxic Cry1Ac protein behind. In vivo, the Polh-Cry1Ac fusion protein showed high insecticidal activity against the pest, Plutella xylostella. Because this novel bio-insecticide employs E. coli as the host, mass production at a low cost should be possible. Also, since this is a protein-based insecticide, living modified organism (LMO) issues such as environmental and ecological safety can be avoided. Copyright 2005 Wiley Periodicals, Inc.

  8. Engineering, expression, and renaturation of a collagen-targeted human bFGF fusion protein.

    Science.gov (United States)

    Andrades, J A; Wu, L T; Hall, F L; Nimni, M E; Becerra, J

    2001-01-01

    Basic fibroblast growth factor (bFGF) is a potent in vitro mitogen for capillary endothelial cells, stimulates angiogenesis in vivo, and may participate in tissue repair. Basic FGF is found in abundance in tissues such as brain, kidney and cartilage. This study reports the expression, purification, and renaturation of a biologically active human basic fibroblast growth factor fusion protein (hbFGF-F1) from Escherichia coli. A prokaryotic expression vector was engineered to produce a tripartite fusion protein consisting of (i) a purification tag, (ii) a protease-sensitive linker/collagen-binding domain, and (iii) cDNA sequence encoding the active fragment of hbFGF. The expressed hbFGF-F1 and hbFGF-F2 (it contains a collagen-binding domain), located in inclusion bodies, were solubilized with 6 M guanidine-HCl and renatured using a glutathione redox system and protracted dialysis under various experimental conditions. The purification of the recombinant proteins was achieved by binding the His-tag of the fusion protein on a Ni-NTA metal chelate column. The biological activity of the recombinant growth factors was demonstrated by their ability to stimulate proliferation of human vein endothelial cells (HVEC), monitored by [3H]-thymidine incorporation, where commercial recombinant human bFGF (rhbFGF) served as a positive control. Purified rhbFGF-F1 and rhbFGF-F2 constructs exhibited proliferative activity comparable to commercial rhbFGF. Binding of the renatured hbFGF-F2 fusion protein to collagen was demonstrated by stable binding on a collagen-conjugated Sephadex-G15 column. The high affinity binding was also demonstrated by the binding of [3H]-collagen to the rhbFGF-F2 protein immobilized on a Ni-NTA column. The rhbFGF-F2 fusion protein bound to collagen coated surfaces with high affinity but exhibited comparatively lower biological activity than the fusion protein in solution, suggesting a potentially latent configuration. Taken together, these results demonstrate

  9. Engineering of a parainfluenza virus type 5 fusion protein (PIV-5 F): development of an autonomous and hyperfusogenic protein by a combinational mutagenesis approach.

    Science.gov (United States)

    Terrier, O; Durupt, F; Cartet, G; Thomas, L; Lina, B; Rosa-Calatrava, M

    2009-12-01

    The entry of enveloped viruses into host cells is accomplished by fusion of the viral envelope with the target cell membrane. For the paramyxovirus parainfluenza virus type 5 (PIV-5), this fusion involves an attachment protein (HN) and a class I viral fusion protein (F). We investigated the effect of 20 different combinations of 12 amino-acid substitutions within functional domains of the PIV-5 F glycoprotein, by performing cell surface expression measurements, quantitative fusion and syncytia assays. We found that combinations of mutations conferring an autonomous phenotype with mutations leading to an increased fusion activity were compatible and generated functional PIV-5 F proteins. The addition of mutations in the heptad-repeat domains led to both autonomous and hyperfusogenic phenotypes, despite the low cell surface expression of the corresponding mutants. Such engineering approach may prove useful not only for deciphering the fundamental mechanism behind viral-mediated membrane fusion but also in the development of potential therapeutic applications.

  10. Comparative study of somatostatin-human serum albumin fusion proteins and natural somatostatin on receptor binding, internalization and activation.

    Directory of Open Access Journals (Sweden)

    Ying Peng

    Full Text Available Albumin fusion technology, the combination of small molecular proteins or peptides with human serum albumin (HSA, is an effective method for improving the medicinal values of natural small molecular proteins or peptides. However, comparative studies between HSA-fusion proteins or peptides and the parent small molecules in biological and molecular mechanisms are less reported. In this study, we examined the binding property of two novel somatostatin-HSA fusion proteins, (SST142-HSA and (SST282-HSA, to human SSTRs in stably expressing SSTR1-5 HEK 293 cells; observed the regulation of receptor internalization and internalized receptor recycling; and detected the receptors activation of HSA fusion proteins in stably expressing SSTR2- and SSTR3-EGFP cells. We showed that both somatostatin-HSA fusion proteins had high affinity to all five SSTRs, stimulated the ERK1/2 phosphorylation and persistently inhibited the accumulation of forskolin-stimulated cAMP in SSTR2- and SSTR3-expressing cells; but were less potent than the synthetic somatostatin-14 (SST-14. Our experiments also showed that somatostatin-HSA fusion proteins did not induce the receptors internalization; rather, they accelerated the recycling of the internalized receptors induced by SST-14 to the plasma membrane. Our results indicated that somatostatin-HSA fusion proteins, different from SST-14, exhibit some particular properties in binding, regulating, and activating somatostatin receptors.

  11. ER/K linked GPCR-G protein fusions systematically modulate second messenger response in cells.

    Science.gov (United States)

    Malik, Rabia U; Dysthe, Matthew; Ritt, Michael; Sunahara, Roger K; Sivaramakrishnan, Sivaraj

    2017-08-10

    FRET and BRET approaches are well established for detecting ligand induced GPCR-G protein interactions in cells. Currently, FRET/BRET assays rely on co-expression of GPCR and G protein, and hence depend on the stoichiometry and expression levels of the donor and acceptor probes. On the other hand, GPCR-G protein fusions have been used extensively to understand the selectivity of GPCR signaling pathways. However, the signaling properties of fusion proteins are not consistent across GPCRs. In this study, we describe and characterize novel sensors based on the Systematic Protein Affinity Strength Modulation (SPASM) technique. Sensors consist of a GPCR and G protein tethered by an ER/K linker flanked by FRET probes. SPASM sensors are tested for the β2-, α1-, and α2- adrenergic receptors, and adenosine type 1 receptor (A 1 R), tethered to Gαs-XL, Gαi 2 , or Gαq subunits. Agonist stimulation of β2-AR and α2-AR increases FRET signal comparable to co-expressed FRET/BRET sensors. SPASM sensors also retain signaling through the endogenous G protein milieu. Importantly, ER/K linker length systematically tunes the GPCR-G protein interaction, with consequent modulation of second messenger signaling for cognate interactions. SPASM GPCR sensors serve the dual purpose of detecting agonist-induced changes in GPCR-G protein interactions, and linking these changes to downstream signaling.

  12. New insights into transcriptional and leukemogenic mechanisms of AML1-ETO and E2A fusion proteins.

    Science.gov (United States)

    Li, Jian; Guo, Chun; Steinauer, Nickolas; Zhang, Jinsong

    2016-08-01

    Nearly 15% of acute myeloid leukemia (AML) cases are caused by aberrant expression of AML1-ETO, a fusion protein generated by the t(8;21) chromosomal translocation. Since its discovery, AML1-ETO has served as a prototype to understand how leukemia fusion proteins deregulate transcription to promote leukemogenesis. Another leukemia fusion protein, E2A-Pbx1, generated by the t(1;19) translocation, is involved in acute lymphoblastic leukemias (ALLs). While AML1-ETO and E2A-Pbx1 are structurally unrelated fusion proteins, we have recently shown that a common axis, the ETO/E-protein interaction, is involved in the regulation of both fusion proteins, underscoring the importance of studying protein-protein interactions in elucidating the mechanisms of leukemia fusion proteins. In this review, we aim to summarize these new developments while also providing a historic overview of the related early studies. A total of 218 publications were reviewed in this article, a majority of which were published after 2004.We also downloaded 3D structures of AML1-ETO domains from Protein Data Bank and provided a systematic summary of their structures. By reviewing the literature, we summarized early and recent findings on AML1-ETO, including its protein-protein interactions, transcriptional and leukemogenic mechanisms, as well as the recently reported involvement of ETO family corepressors in regulating the function of E2A-Pbx1. While the recent development in genomic and structural studies has clearly demonstrated that the fusion proteins function by directly regulating transcription, a further understanding of the underlying mechanisms, including crosstalk with other transcription factors and cofactors, and the protein-protein interactions in the context of native proteins, may be necessary for the development of highly targeted drugs for leukemia therapy.

  13. Entamoeba histolytica: identification and characterization of an N-ethylmaleimide sensitive fusion protein homologue.

    Science.gov (United States)

    Libros-Ziv, Pazit; Villalobo, Eduardo; Mirelman, David

    2005-07-01

    Entamoeba histolytica is a phagocytic cell with numerous vesicles of different sizes and shapes but without a well-defined Golgi apparatus. Despite this, genes implied in membrane trafficking have been identified in the genome of this parasite. One of these genes is homologous to the N-ethylmaleimide sensitive fusion factor (NSF), whose protein has been shown to play an important role in vesicle fusion in other eukaryotic cells. In this report, we investigated the NSF homologue gene from a pathogenic E. histolytica, characterized its protein product and two of its activities, ATPase and in vitro intra-Golgi transport. The finding of an active NSF protein in E. histolytica indicates that a simple or primordial Golgi apparatus probably exists in this microorganism, as has been proposed by others.

  14. Characterization of the Klebsiella aerogenes Urease Accessory Protein UreD in Fusion with the Maltose Binding Protein

    OpenAIRE

    Carter, Eric L.; Hausinger, Robert P.

    2010-01-01

    Assembly of the Klebsiella aerogenes urease metallocenter requires four accessory proteins, UreD, UreE, UreF, and UreG, to effectively deliver and incorporate two Ni2+ ions into the nascent active site of the urease apoprotein (UreABC). Each accessory protein has been purified and characterized with the exception of UreD due to its insolubility when it is overproduced in recombinant cells. In this study, a translational fusion was made between the maltose binding protein (MBP) and UreD, with ...

  15. Sorting of growth hormone-erythropoietin fusion proteins in rat salivary glands

    International Nuclear Information System (INIS)

    Samuni, Yuval; Zheng Changyu; Cawley, Niamh X.; Cotrim, Ana P.; Loh, Y. Peng; Baum, Bruce J.

    2008-01-01

    Neuroendocrine and exocrine cells secrete proteins in either a constitutive manner or via the regulated secretory pathway (RSP), but the specific sorting mechanisms involved are not fully understood. After gene transfer to rat salivary glands, the transgenic model proteins human growth hormone (hGH) and erythropoietin (hEpo) are secreted primarily into saliva (RSP; exocrine) and serum (constitutive; endocrine), respectively. We hypothesized that fusion of hGH at either the C-terminus or the N-terminus of hEpo would re-direct hEpo from the bloodstream into saliva. We constructed and expressed two fusion proteins, hEpo-hGH and hGH-hEpo, using serotype 5-adenoviral vectors, and delivered them to rat submandibular glands in vivo via retroductal cannulation. Both the hEpo-hGH and hGH-hEpo fusion proteins, but not hEpo alone, were secreted primarily into saliva (p < 0.0001 and p = 0.0083, respectively). These in vivo studies demonstrate for the first time that hGH, in an N- as well as C-terminal position, influences the secretion of a constitutive pathway protein

  16. Biophysical Properties and Antiviral Activities of Measles Fusion Protein Derived Peptide Conjugated with 25-Hydroxycholesterol.

    Science.gov (United States)

    Gomes, Bárbara; Santos, Nuno C; Porotto, Matteo

    2017-10-31

    Measles virus (MV) infection is re-emerging, despite the availability of an effective vaccine. The mechanism of MV entry into a target cell relies on coordinated action between the MV hemagglutinin (H) receptor binding protein and the fusion envelope glycoprotein (F) which mediates fusion between the viral and cell membranes. Peptides derived from the C -terminal heptad repeat (HRC) of F can interfere with this process, blocking MV infection. As previously described, biophysical properties of HRC-derived peptides modulate their antiviral potency. In this work, we characterized a MV peptide fusion inhibitor conjugated to 25-hydroxycholesterol (25HC), a cholesterol derivative with intrinsic antiviral activity, and evaluated its interaction with membrane model systems and human blood cells. The peptide (MV.

  17. An ER-directed fusion protein comprising a bacterial subtilisin ...

    African Journals Online (AJOL)

    nausch

    Many recombinant therapeutic proteins have been expressed in transgenic plants to demonstrate proof-of- concept and there have been significant improvements in yields (Sharma and Sharma, 2009). However, downstream processing costs remain a major constraint for the commercial development of plant-derived.

  18. Expression of human serum albumin--L7/L12 (Brucella abortus ribosomal protein) fusion protein in Saccharomyces cerevisiae.

    Science.gov (United States)

    Pakzad, Iraj; Rezaee, Abbas; Emaneini, Mohammad; Hosseini, Ahmad Zavaran; Tabbaraee, Bahman; Taherikalani, Morovat

    2009-01-01

    Brucella abortus is a facultative intracellular gram-negative bacterial pathogen that causes abortion in pregnant cattle and undulant fever in humans. The immunogenic B. abortus ribosomal protein L7/L12 is a promising candidate antigen for the development of subunit vaccines against brucellosis. It has already been expressed in several bacteria and has been used as DNA vaccine. In order to construct yeast expressing vector for the tHSA-L7/L12 fusion protein, the l7/l12 ribosomal gene was amplified by PCR. The expression plasmid pYtHSA-L7/L12 was constructed by inserting the L7/L12 gene into the pYHSA5 shuttle vector (containing inulinase signal sequence, HSA gene and Gal10 promoter). The recombinant vector was transformed into S. cerevisiae and was then induced by galactose. The secreted recombinant fusion protein was detected in supernatant by SDS-PAGE and confirmed by western blot analysis using anti-HSA and anti-L7/L12 antibodies. Fusion protein was purified by affinity chromatography and its amount was approximately 500 microg/liter.

  19. [Construction of cTnC-linker-TnI (P) Genes, Expression of Fusion Protein and Preparation of Lyophilized Protein].

    Science.gov (United States)

    Song, Xiaoli; Liu, Xiaoyun; Cai, Lei; Wu, Jianwei; Wang, Jihua

    2015-12-01

    In order to construct and express human cardiac troponin C-linker-troponin I(P) [ cTnC-linker-TnI(P)] fusion protein, detect its activity and prepare lyophilized protein, we searched the CDs of human cTnC and cTnI from GenBank, synthesized cTnC and cTnI(30-110aa) into cloning vector by a short DNA sequence coding for 15 neutral amino acid residues. pCold I-cTnC-linker-TnI(P) was constructed and transformed into E. coli BL21(DE3). Then, cTnC-linker-TnI(P) fusion protein was induced by isopropyl-β-D-thiogalactopyranoside (IPTG). Soluable expression of cTnC-linker-TnI(P) in prokaryotic system was successfully obtained. The fusion protein was purified by Ni²⁺ Sepharose 6 Fast Flow affinity chromatography with over 95% purity and prepared into lyophilized protein. The activity of purified cTnC-linker-TnI(P) and its lyophilized protein were detected by Wondfo Finecare™ cTnI Test. Lyophilized protein of cTnC-linker-TnI(P) was stable for 10 or more days at 37 °C and 4 or more months at 25 °C and 4 °C. The expression system established in this research is feasible and efficient. Lyophilized protein is stable enough to be provided as biological raw materials for further research.

  20. The fusion-related hydrophobic domain of Sendai F protein can be moved through the cytoplasmic membrane of Escherichia coli.

    OpenAIRE

    Davis, N G; Hsu, M C

    1986-01-01

    Recent work on a prokaryotic membrane protein, gene III protein (pIII) of coliphage f1, showed that polypeptide segments of sufficient hydrophobicity functioned to stop transfer of the polypeptide across the cell membrane: strings of 16 or more hydrophobic amino acids sufficed. A fusion-related hydrophobic domain (FRHD) of Sendai F protein, a sequence of 26 consecutive uncharged residues, has been implicated in the fusion of the viral membrane envelope and the target-cell membrane through a h...

  1. High-yield membrane protein expression from E. coli using an engineered outer membrane protein F fusion.

    Science.gov (United States)

    Su, Pin-Chuan; Si, William; Baker, Deidre L; Berger, Bryan W

    2013-04-01

    Obtaining high yields of membrane proteins necessary to perform detailed structural study is difficult due to poor solubility and variability in yields from heterologous expression systems. To address this issue, an Escherichia coli-based membrane protein overexpression system utilizing an engineered bacterial outer membrane protein F (pOmpF) fusion has been developed. Full-length human receptor activity-modifying protein 1 (RAMP1) was expressed using pOmpF, solubilized in FC15 and purified to homogeneity. Using circular dichroism and fluorescence spectroscopy, purified full-length RAMP1 is composed of approximately 90% α-helix, and retains its solubility and structure in FC15 over a wide range of temperatures (20-60°C). Thus, our approach provides a useful, complementary approach to achieve high-yield, full-length membrane protein overexpression for biophysical studies. Copyright © 2013 The Protein Society.

  2. Production of FMDV virus-like particles by a SUMO fusion protein approach in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Liang Shu-Mei

    2009-08-01

    Full Text Available Abstract Virus-like particles (VLPs are formed by the self-assembly of envelope and/or capsid proteins from many viruses. Some VLPs have been proven successful as vaccines, and others have recently found applications as carriers for foreign antigens or as scaffolds in nanoparticle biotechnology. However, production of VLP was usually impeded due to low water-solubility of recombinant virus capsid proteins. Previous studies revealed that virus capsid and envelope proteins were often posttranslationally modified by SUMO in vivo, leading into a hypothesis that SUMO modification might be a common mechanism for virus proteins to retain water-solubility or prevent improper self-aggregation before virus assembly. We then propose a simple approach to produce VLPs of viruses, e.g., foot-and-mouth disease virus (FMDV. An improved SUMO fusion protein system we developed recently was applied to the simultaneous expression of three capsid proteins of FMDV in E. coli. The three SUMO fusion proteins formed a stable heterotrimeric complex. Proteolytic removal of SUMO moieties from the ternary complexes resulted in VLPs with size and shape resembling the authentic FMDV. The method described here can also apply to produce capsid/envelope protein complexes or VLPs of other disease-causing viruses.

  3. The Fusion Protein Specificity of the Parainfluenza Virus Hemagglutinin-Neuraminidase Protein Is Not Solely Defined by the Primary Structure of Its Stalk Domain.

    Science.gov (United States)

    Tsurudome, Masato; Ito, Morihiro; Ohtsuka, Junpei; Hara, Kenichiro; Komada, Hiroshi; Nishio, Machiko; Nosaka, Tetsuya

    2015-12-01

    Virus-specific interaction between the attachment protein (HN) and the fusion protein (F) is prerequisite for the induction of membrane fusion by parainfluenza viruses. This HN-F interaction presumably is mediated by particular amino acids in the HN stalk domain and those in the F head domain. We found in the present study, however, that a simian virus 41 (SV41) F-specific chimeric HPIV2 HN protein, SCA, whose cytoplasmic, transmembrane, and stalk domains were derived from the SV41 HN protein, could not induce cell-cell fusion of BHK-21 cells when coexpressed with an SV41 HN-specific chimeric PIV5 F protein, no. 36. Similarly, a headless form of the SV41 HN protein failed to induce fusion with chimera no. 36, whereas it was able to induce fusion with the SV41 F protein. Interestingly, replacement of 13 amino acids of the SCA head domain, which are located at or around the dimer interface of the head domain, with SV41 HN counterparts resulted in a chimeric HN protein, SCA-RII, which induced fusion with chimera no. 36 but not with the SV41 F protein. More interestingly, retroreplacement of 11 out of the 13 amino acids of SCA-RII with the SCA counterparts resulted in another chimeric HN protein, IM18, which induced fusion either with chimera no. 36 or with the SV41 F protein, similar to the SV41 HN protein. Thus, we conclude that the F protein specificity of the HN protein that is observed in the fusion event is not solely defined by the primary structure of the HN stalk domain. It is appreciated that the HN head domain initially conceals the HN stalk domain but exposes it after the head domain has bound to the receptors, which allows particular amino acids in the stalk domain to interact with the F protein and trigger it to induce fusion. However, other regulatory roles of the HN head domain in the fusion event have been ill defined. We have shown in the current study that removal of the head domain or amino acid substitutions in a particular region of the head

  4. A Type-2 fuzzy data fusion approach for building reliable weighted protein interaction networks with application in protein complex detection.

    Science.gov (United States)

    Mehranfar, Adele; Ghadiri, Nasser; Kouhsar, Morteza; Golshani, Ashkan

    2017-09-01

    Detecting the protein complexes is an important task in analyzing the protein interaction networks. Although many algorithms predict protein complexes in different ways, surveys on the interaction networks indicate that about 50% of detected interactions are false positives. Consequently, the accuracy of existing methods needs to be improved. In this paper we propose a novel algorithm to detect the protein complexes in 'noisy' protein interaction data. First, we integrate several biological data sources to determine the reliability of each interaction and determine more accurate weights for the interactions. A data fusion component is used for this step, based on the interval type-2 fuzzy voter that provides an efficient combination of the information sources. This fusion component detects the errors and diminishes their effect on the detection protein complexes. So in the first step, the reliability scores have been assigned for every interaction in the network. In the second step, we have proposed a general protein complex detection algorithm by exploiting and adopting the strong points of other algorithms and existing hypotheses regarding real complexes. Finally, the proposed method has been applied for the yeast interaction datasets for predicting the interactions. The results show that our framework has a better performance regarding precision and F-measure than the existing approaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Endocytosis Plays a Critical Role in Proteolytic Processing of the Hendra Virus Fusion Protein

    OpenAIRE

    Meulendyke, Kelly Ann; Wurth, Mark Allen; McCann, Richard O.; Dutch, Rebecca Ellis

    2005-01-01

    The Hendra virus fusion (F) protein is synthesized as a precursor protein, F0, which is proteolytically processed to the mature form, F1+F2. Unlike the case for the majority of paramyxovirus F proteins, the processing event is furin independent, does not require the addition of exogenous proteases, is not affected by reductions in intracellular Ca2+, and is strongly affected by conditions that raise the intracellular pH (C. T. Pager, M. A. Wurth, and R. E. Dutch, J. Virol. 78:9154-9163, 2004)...

  6. Effect of linker length and residues on the structure and stability of a fusion protein with malaria vaccine application.

    Science.gov (United States)

    Shamriz, Shabnam; Ofoghi, Hamideh; Moazami, Nasrin

    2016-09-01

    Recombinant protein technology has revolutionized the world of biology and medicine. Following this progress, fusion protein technology, as a novel innovation, has opened new horizons for the development of proteins that do not naturally exist. Fusion proteins are generated via genetically fusing two or more genes coding for separate proteins, thus the product is a single protein having functional properties of both proteins. As an indispensable element in fusion protein construction, linkers are used to separate the functional domains in order to improve their expression, folding and stability. We computationally fused an antigen and an adjuvant together using different linkers to obtain a two-domain fusion construct which can potentially act as an oral vaccine candidate against malaria. We then predicted the structures computationally to find out the probable folding of each domain in the designed construct. One of the fusion constructs was selected based on the highest value for C-score. Ramchandran Plot analysis represented that most residues were fallen in favorable regions. Our in silico analysis showed that (GGGGS)3 linker confers the best structure and stability for our target fusion protein. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Analysis of nuclear export using photoactivatable GFP fusion proteins and interspecies heterokaryons.

    Science.gov (United States)

    Nakrieko, Kerry-Ann; Ivanova, Iordanka A; Dagnino, Lina

    2010-01-01

    In this chapter, we review protocols for the analysis of nucleocytoplasmic shuttling of transcription factors and nuclear proteins, using two different approaches. The first involves the use of photoactivatable forms of the protein of interest by fusion to photoactivatable green fluorescent protein to follow its movement out of the nucleus by live-cell confocal microscopy. This methodology allows for the kinetic characterization of protein movements as well as measurement of steady-state levels. In a second procedure to assess the ability of a nuclear protein to move into and out of the nucleus, we describe the use of interspecies heterokaryon assays, which provide a measurement of steady-state distribution. These technologies are directly applicable to the analysis of nucleocytoplasmic movements not only of transcription factors, but also other nuclear proteins.

  8. Vaccinia mature virus fusion regulator A26 protein binds to A16 and G9 proteins of the viral entry fusion complex and dissociates from mature virions at low pH.

    Science.gov (United States)

    Chang, Shu-Jung; Shih, Ao-Chun; Tang, Yin-Liang; Chang, Wen

    2012-04-01

    Vaccinia mature virus enters cells through either endocytosis or plasma membrane fusion, depending on virus strain and cell type. Our previous results showed that vaccinia virus mature virions containing viral A26 protein enter HeLa cells preferentially through endocytosis, whereas mature virions lacking A26 protein enter through plasma membrane fusion, leading us to propose that A26 acts as an acid-sensitive fusion suppressor for mature virus (S. J. Chang, Y. X. Chang, R. Izmailyan R, Y. L. Tang, and W. Chang, J. Virol. 84:8422-8432, 2010). In the present study, we investigated the fusion suppression mechanism of A26 protein. We found that A26 protein was coimmunoprecipitated with multiple components of the viral entry-fusion complex (EFC) in infected HeLa cells. Transient expression of viral EFC components in HeLa cells revealed that vaccinia virus A26 protein interacted directly with A16 and G9 but not with G3, L5 and H2 proteins of the EFC components. Consistently, a glutathione S-transferase (GST)-A26 fusion protein, but not GST, pulled down A16 and G9 proteins individually in vitro. Together, our results supported the idea that A26 protein binds to A16 and G9 protein at neutral pH contributing to suppression of vaccinia virus-triggered membrane fusion from without. Since vaccinia virus extracellular envelope proteins A56/K2 were recently shown to bind to the A16/G9 subcomplex to suppress virus-induced fusion from within, our results also highlight an evolutionary convergence in which vaccinia viral fusion suppressor proteins regulate membrane fusion by targeting the A16 and G9 components of the viral EFC complex. Finally, we provide evidence that acid (pH 4.7) treatment induced A26 protein and A26-A27 protein complexes of 70 kDa and 90 kDa to dissociate from mature virions, suggesting that the structure of A26 protein is acid sensitive.

  9. Development and use of IgM/J-chain fusion proteins for characterization of immunoglobulin superfamily ligand-receptor interactions.

    Science.gov (United States)

    Ammann, Johannes U; Trowsdale, John

    2014-02-03

    Discovery of binding partners for immunoglobulin molecules expressed by cells of the immune system is an important topic of current research. However, many ligand-receptor interactions are of low affinity, and hence detection is refractory to most established protocols. We evaluated fusion proteins based on human IgM as high avidity probes to screen for ligand-receptor binding. We describe methods for cloning, expression, and quantification of IgM fusion proteins with J-chain. Furthermore, we outline protocols to assess binding of IgM fusion proteins to cells and to plate-bound proteins. Compared to standard IgG-fusion proteins, IgM + J chain increased binding of a test interaction, PD-L1 to PD-1, up to 1000-fold. Copyright © 2014 John Wiley & Sons, Inc.

  10. Solid-State Nuclear Magnetic Resonance Investigation of the Structural Topology and Lipid Interactions of a Viral Fusion Protein Chimera Containing the Fusion Peptide and Transmembrane Domain.

    Science.gov (United States)

    Yao, Hongwei; Lee, Myungwoon; Liao, Shu-Yu; Hong, Mei

    2016-12-13

    The fusion peptide (FP) and transmembrane domain (TMD) of viral fusion proteins play important roles during virus-cell membrane fusion, by inducing membrane curvature and transient dehydration. The structure of the water-soluble ectodomain of viral fusion proteins has been extensively studied crystallographically, but the structures of the FP and TMD bound to phospholipid membranes are not well understood. We recently investigated the conformations and lipid interactions of the separate FP and TMD peptides of parainfluenza virus 5 (PIV5) fusion protein F using solid-state nuclear magnetic resonance. These studies provide structural information about the two domains when they are spatially well separated in the fusion process. To investigate how these two domains are structured relative to each other in the postfusion state, when the ectodomain forms a six-helix bundle that is thought to force the FP and TMD together in the membrane, we have now expressed and purified a chimera of the FP and TMD, connected by a Gly-Lys linker, and measured the chemical shifts and interdomain contacts of the protein in several lipid membranes. The FP-TMD chimera exhibits α-helical chemical shifts in all the membranes examined and does not cause strong curvature of lamellar membranes or membranes with negative spontaneous curvature. These properties differ qualitatively from those of the separate peptides, indicating that the FP and TMD interact with each other in the lipid membrane. However, no 13 C- 13 C cross peaks are observed in two-dimensional correlation spectra, suggesting that the two helices are not tightly associated. These results suggest that the ectodomain six-helix bundle does not propagate into the membrane to the two hydrophobic termini. However, the loosely associated FP and TMD helices are found to generate significant negative Gaussian curvature to membranes that possess spontaneous positive curvature, consistent with the notion that the FP-TMD assembly may

  11. The transmembrane domain and acidic lipid flip-flop regulates voltage-dependent fusion mediated by class II and III viral proteins.

    Directory of Open Access Journals (Sweden)

    Ruben M Markosyan

    Full Text Available Voltage dependence of fusion induced by class II and class III viral fusion proteins was investigated. Class II proteins from Ross River and Sindbus virus and a mutant class III protein from Epstein Barr virus were found to induce cell-cell fusion that is voltage dependent. Combined with previous studies, in all, four class II and two class III protein have now been shown to exhibit voltage-dependent fusion, demonstrating that this is probably a general phenomenon for these two classes of viral fusion proteins. In the present study, monitoring fusion of pseudovirus expressing Vesicular Stomatitis virus (VSV G within endosomes shows that here, too, fusion is voltage dependent. This supports the claim that voltage dependence of fusion is biologically relevant and that cell-cell fusion reliably models the voltage dependence. Fusion induced by class I viral proteins is independent of voltage; chimeras expressing the ectodomain of a class I fusion protein and the transmembrane domain of VSV G could therefore be used to explore the location within the protein responsible for voltage dependence. Results showed that the transmembrane domain is the region associated with voltage dependence. Experiments in which cells were enriched with acidic lipids led to the conclusion that it is the flip-flop of acidic lipids that carries the charge responsible for the observed voltage dependence of fusion. This flip-flop occurred downstream of hemifusion, in accord with previous findings that the voltage dependent steps of fusion occur at a stage subsequent to hemifusion.

  12. Nuclear localization and transactivating capacities of the papillary renal cell carcinoma-associated TFE3 and PRCC (fusion) proteins

    NARCIS (Netherlands)

    Weterman, M. A. J.; van Groningen, J. J.; Jansen, A.; van Kessel, A. G.

    2000-01-01

    The papillary renal cell carcinoma-associated t(X;1)(p11;q21) leads to fusion of the transcription factor TFE3 gene on the X-chromosome to a novel gene, PRCC, on chromosome 1. As a result, two putative fusion proteins are formed: PRCCTFE3, which contains all known domains for DNA binding,

  13. Purification method for recombinant proteins based on a fusion between the target protein and the C-terminus of calmodulin

    Science.gov (United States)

    Schauer-Vukasinovic, Vesna; Deo, Sapna K.; Daunert, Sylvia

    2002-01-01

    Calmodulin (CaM) was used as an affinity tail to facilitate the purification of the green fluorescent protein (GFP), which was used as a model target protein. The protein GFP was fused to the C-terminus of CaM, and a factor Xa cleavage site was introduced between the two proteins. A CaM-GFP fusion protein was expressed in E. coli and purified on a phenothiazine-derivatized silica column. CaM binds to the phenothiazine on the column in a Ca(2+)-dependent fashion and it was, therefore, used as an affinity tail for the purification of GFP. The fusion protein bound to the affinity column was then subjected to a proteolytic digestion with factor Xa. Pure GFP was eluted with a Ca(2+)-containing buffer, while CaM was eluted later with a buffer containing the Ca(2+)-chelating agent EGTA. The purity of the isolated GFP was verified by SDS-PAGE, and the fluorescence properties of the purified GFP were characterized.

  14. In vitro Activity and Function of B7-H4-Ig Fusion Protein

    DEFF Research Database (Denmark)

    Rasmussen, Susanne B; Kosicki, Michael; Svendsen, Signe Goul

    2013-01-01

    -Ig fusion protein has been documented to assuage the symptoms in mouse models of RA, T1D, and multiple sclerosis in vivo. In the present study, B7-H4-Ig bound to the majority of human peripheral blood monocytes and NK cells, but not to either normal or activated T cells. B7-H4-Ig fusion protein...... was assayed for its effects in allogeneic mixed lymphocyte culture (MLC) systems. Soluble B7- H4-Ig had no significant effect in the MLC, but with a tendency to promote allogeneic response. Immobilized, but not soluble B7-H4-Ig inhibited plastic bound anti-CD3 mediated activation of T cells. This inhibition...

  15. Measles Virus Mutants Possessing the Fusion Protein with Enhanced Fusion Activity Spread Effectively in Neuronal Cells, but Not in Other Cells, without Causing Strong Cytopathology

    Science.gov (United States)

    Ohno, Shinji; Shirogane, Yuta; Suzuki, Satoshi O.; Koga, Ritsuko

    2014-01-01

    ABSTRACT Subacute sclerosing panencephalitis (SSPE) is caused by persistent measles virus (MV) infection in the central nervous system (CNS). Since human neurons, its main target cells, do not express known MV receptors (signaling lymphocyte activation molecule [SLAM] and nectin 4), it remains to be understood how MV infects and spreads in them. We have recently reported that fusion-enhancing substitutions in the extracellular domain of the MV fusion (F) protein (T461I and S103I/N462S/N465S), which are found in multiple SSPE virus isolates, promote MV spread in human neuroblastoma cell lines and brains of suckling hamsters. In this study, we show that hyperfusogenic viruses with these substitutions also spread efficiently in human primary neuron cultures without inducing syncytia. These substitutions were found to destabilize the prefusion conformation of the F protein trimer, thereby enhancing fusion activity. However, these hyperfusogenic viruses exhibited stronger cytopathology and produced lower titers at later time points in SLAM- or nectin 4-expressing cells compared to the wild-type MV. Although these viruses spread efficiently in the brains of SLAM knock-in mice, they did not in the spleens. Taken together, the results suggest that enhanced fusion activity is beneficial for MV to spread in neuronal cells where no cytopathology occurs, but detrimental to other types of cells due to strong cytopathology. Acquisition of enhanced fusion activity through substitutions in the extracellular domain of the F protein may be crucial for MV's extensive spread in the CNS and development of SSPE. IMPORTANCE Subacute sclerosing panencephalitis (SSPE) is a fatal disease caused by persistent measles virus (MV) infection in the central nervous system (CNS). Its cause is not well understood, and no effective therapy is currently available. Recently, we have reported that enhanced fusion activity of MV through the mutations in its fusion protein is a major determinant of

  16. Sequential Conformational Changes in the Morbillivirus Attachment Protein Initiate the Membrane Fusion Process

    Science.gov (United States)

    Ader-Ebert, Nadine; Khosravi, Mojtaba; Herren, Michael; Avila, Mislay; Alves, Lisa; Bringolf, Fanny; Örvell, Claes; Langedijk, Johannes P.; Zurbriggen, Andreas; Plemper, Richard K.; Plattet, Philippe

    2015-01-01

    Despite large vaccination campaigns, measles virus (MeV) and canine distemper virus (CDV) cause major morbidity and mortality in humans and animals, respectively. The MeV and CDV cell entry system relies on two interacting envelope glycoproteins: the attachment protein (H), consisting of stalk and head domains, co-operates with the fusion protein (F) to mediate membrane fusion. However, how receptor-binding by the H-protein leads to F-triggering is not fully understood. Here, we report that an anti-CDV-H monoclonal antibody (mAb-1347), which targets the linear H-stalk segment 126-133, potently inhibits membrane fusion without interfering with H receptor-binding or F-interaction. Rather, mAb-1347 blocked the F-triggering function of H-proteins regardless of the presence or absence of the head domains. Remarkably, mAb-1347 binding to headless CDV H, as well as standard and engineered bioactive stalk-elongated CDV H-constructs treated with cells expressing the SLAM receptor, was enhanced. Despite proper cell surface expression, fusion promotion by most H-stalk mutants harboring alanine substitutions in the 126-138 “spacer” section was substantially impaired, consistent with deficient receptor-induced mAb-1347 binding enhancement. However, a previously reported F-triggering defective H-I98A variant still exhibited the receptor-induced “head-stalk” rearrangement. Collectively, our data spotlight a distinct mechanism for morbillivirus membrane fusion activation: prior to receptor contact, at least one of the morbillivirus H-head domains interacts with the membrane-distal “spacer” domain in the H-stalk, leaving the F-binding site located further membrane-proximal in the stalk fully accessible. This “head-to-spacer” interaction conformationally stabilizes H in an auto-repressed state, which enables intracellular H-stalk/F engagement while preventing the inherent H-stalk’s bioactivity that may prematurely activate F. Receptor-contact disrupts the

  17. Targeted delivery of siRNA into breast cancer cells via phage fusion proteins.

    Science.gov (United States)

    Bedi, Deepa; Gillespie, James W; Petrenko, Vasily A; Ebner, Andreas; Leitner, Michael; Hinterdorfer, Peter; Petrenko, Valery A

    2013-02-04

    Nucleic acids, including antisense oligonucleotides, small interfering RNA (siRNA), aptamers, and rybozymes, emerged as versatile therapeutics due to their ability to interfere in a well-planned manner with the flow of genetic information from DNA to protein. However, a systemic use of NAs is hindered by their instability in physiological liquids and inability of intracellular accumulation in the site of action. We first evaluated the potential of cancer specific phage fusion proteins as targeting ligands that provide encapsulation, protection, and navigation of siRNA to the target cell. The tumor-specific proteins were isolated from phages that were affinity selected from a landscape phage library against target breast cancer cells. It was found that fusion phage coat protein fpVIII displaying cancer-targeting peptides can effectively encapsulate siRNAs and deliver them into the cells leading to specific silencing of the model gene GAPDH. Complexes of siRNA and phage protein form nanoparticles (nanophages), which were characterized by atomic force microscopy and ELISA, and their stability was demonstrated by resistance of encapsulated siRNA to degradation by serum nucleases. The phage protein/siRNA complexes can make a new type of highly selective, stable, active, and physiologically acceptable cancer nanomedicine.

  18. A recombinant fusion protein-based, fluorescent protease assay for high throughput-compatible substrate screening.

    Science.gov (United States)

    Bozóki, Beáta; Gazda, Lívia; Tóth, Ferenc; Miczi, Márió; Mótyán, János András; Tőzsér, József

    2018-01-01

    In connection with the intensive investigation of proteases, several methods have been developed for analysis of the substrate specificity. Due to the great number of proteases and the expected target molecules to be analyzed, time- and cost-efficient high-throughput screening (HTS) methods are preferred. Here we describe the development and application of a separation-based HTS-compatible fluorescent protease assay, which is based on the use of recombinant fusion proteins as substrates of proteases. The protein substrates used in this assay consists of N-terminal (hexahistidine and maltose binding protein) fusion tags, cleavage sequences of the tobacco etch virus (TEV) and HIV-1 proteases, and a C-terminal fluorescent protein (mApple or mTurquoise2). The assay is based on the fluorimetric detection of the fluorescent proteins, which are released from the magnetic bead-attached substrates by the proteolytic cleavage. The protease assay has been applied for activity measurements of TEV and HIV-1 proteases to test the suitability of the system for enzyme kinetic measurements, inhibition studies, and determination of pH optimum. We also found that denatured fluorescent proteins can be renatured after SDS-PAGE of denaturing conditions, but showed differences in their renaturation abilities. After in-gel renaturation both substrates and cleavage products can be identified by in-gel UV detection. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Sequence motifs and prokaryotic expression of the reptilian paramyxovirus fusion protein

    Science.gov (United States)

    Franke, J.; Batts, W.N.; Ahne, W.; Kurath, G.; Winton, J.R.

    2006-01-01

    Fourteen reptilian paramyxovirus isolates were chosen to represent the known extent of genetic diversity among this novel group of viruses. Selected regions of the fusion (F) gene were sequenced, analyzed and compared. The F gene of all isolates contained conserved motifs homologous to those described for other members of the family Paramyxoviridae including: signal peptide, transmembrane domain, furin cleavage site, fusion peptide, N-linked glycosylation sites, and two heptad repeats, the second of which (HRB-LZ) had the characteristics of a leucine zipper. Selected regions of the fusion gene of isolate Gono-GER85 were inserted into a prokaryotic expression system to generate three recombinant protein fragments of various sizes. The longest recombinant protein was cleaved by furin into two fragments of predicted length. Western blot analysis with virus-neutralizing rabbit-antiserum against this isolate demonstrated that only the longest construct reacted with the antiserum. This construct was unique in containing 30 additional C-terminal amino acids that included most of the HRB-LZ. These results indicate that the F genes of reptilian paramyxoviruses contain highly conserved motifs typical of other members of the family and suggest that the HRB-LZ domain of the reptilian paramyxovirus F protein contains a linear antigenic epitope. ?? Springer-Verlag 2005.

  20. Nitrilase and Fhit homologs are encoded as fusion proteins in Drosophila melanogaster and Caenorhabditis elegans

    Science.gov (United States)

    Pekarsky, Yuri; Campiglio, Manuela; Siprashvili, Zurab; Druck, Teresa; Sedkov, Yurii; Tillib, Sergei; Draganescu, Alexandra; Wermuth, Peter; Rothman, Joel H.; Huebner, Kay; Buchberg, Arthur M.; Mazo, Alexander; Brenner, Charles; Croce, Carlo M.

    1998-01-01

    The tumor suppressor gene FHIT encompasses the common human chromosomal fragile site at 3p14.2 and numerous cancer cell biallelic deletions. To study Fhit function we cloned and characterized FHIT genes from Drosophila melanogaster and Caenorhabditis elegans. Both genes code for fusion proteins in which the Fhit domain is fused with a novel domain showing homology to bacterial and plant nitrilases; the D. melanogaster fusion protein exhibited diadenosine triphosphate (ApppA) hydrolase activity expected of an authentic Fhit homolog. In human and mouse, the nitrilase homologs and Fhit are encoded by two different genes: FHIT and NIT1, localized on chromosomes 3 and 1 in human, and 14 and 1 in mouse, respectively. We cloned and characterized human and murine NIT1 genes and determined their exon-intron structure, patterns of expression, and alternative processing of their mRNAs. The tissue specificity of expression of murine Fhit and Nit1 genes was nearly identical. Because fusion proteins with dual or triple enzymatic activities have been found to carry out specific steps in a given biochemical or biosynthetic pathway, we postulate that Fhit and Nit1 likewise collaborate in a biochemical or cellular pathway in mammalian cells. PMID:9671749

  1. IQCJ-SCHIP1, a novel fusion transcript encoding a calmodulin-binding IQ motif protein

    International Nuclear Information System (INIS)

    Kwasnicka-Crawford, Dorota A.; Carson, Andrew R.; Scherer, Stephen W.

    2006-01-01

    The existence of transcripts that span two adjacent, independent genes is considered rare in the human genome. This study characterizes a novel human fusion gene named IQCJ-SCHIP1. IQCJ-SCHIP1 is the longest isoform of a complex transcriptional unit that bridges two separate genes that encode distinct proteins, IQCJ, a novel IQ motif containing protein and SCHIP1, a schwannomin interacting protein that has been previously shown to interact with the Neurofibromatosis type 2 (NF2) protein. IQCJ-SCHIP1 is located on the chromosome 3q25 and comprises a 1692-bp transcript encompassing 11 exons spanning 828 kb of the genomic DNA. We show that IQCJ-SCHIP1 mRNA is highly expressed in the brain. Protein encoded by the IQCJ-SCHIP1 gene was localized to cytoplasm and actin-rich regions and in differentiated PC12 cells was also seen in neurite extensions

  2. Dimeric and trimeric fusion proteins generated with fimbrial adhesins of uropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Víctor Manuel Luna-Pineda

    2016-10-01

    Full Text Available Urinary tract infections (UTIs are associated with high rates of morbidity and mortality worldwide, and uropathogenic Escherichia coli (UPEC is the main etiologic agent. Fimbriae assembled on the bacterial surface are essential for adhesion in the urinary tract epithelium. In this study, the FimH, CsgA, and PapG adhesins were fused to generate biomolecules as potential target vaccines against UTIs. The fusion protein design was generated using bioinformatics tools, and template fusion gene sequences were synthesized by GenScript in the following order fimH-csgA-papG-fimH-csgA (fcpfc linked to the nucleotide sequence encoding the EAAAK5 peptide. Monomeric (fimH, csgA, and papG, dimeric (fimH-csgA, and trimeric (fimH-csgA-papG genes were cloned into the pLATE31 expression vector and generated products of 1040, 539, 1139, 1442, and 2444 bp, respectively. Fusion protein expression in BL21 E. coli was induced with 1 mM IPTG, and His-tagged fusion proteins were purified under denaturing conditions and refolded by dialysis using C-buffer. Coomassie blue-stained SDS-PAGE gels and Western blot analysis revealed bands of 29.5, 11.9, 33.9, 44.9, and 82.1 kDa corresponding to FimH, CsgA, PapG, FC, and FCP proteins, respectively. Mass spectrometry analysis by MALDI-TOF/TOF revealed specific peptides that confirmed the fusion protein structures. Dynamic light scattering analysis revealed the polydispersed state of the fusion proteins. The FimH, CsgA, and PapG stimulated the release of 372 to 398 pg/mL IL-6; interestingly, the FC and FCP stimulated the release of 464.79 pg/mL (p ≤ 0.018 and 521.24 pg/mL (p ≤ 0.002 IL-6, respectively. In addition, the FC and FCP stimulated the release of 398.52 pg/mL (p ≤ 0.001 and 450.40 pg/mL (p ≤ 0.002 IL-8, respectively. High levels of IgA and IgG antibodies in human sera reacted against the fusion proteins, and under identical conditions, low levels of IgA and IgG antibodies were detected in human urine. Rabbit

  3. Determination of the topology of endoplasmic reticulum membrane proteins using redox-sensitive green-fluorescence protein fusions.

    Science.gov (United States)

    Tsachaki, Maria; Birk, Julia; Egert, Aurélie; Odermatt, Alex

    2015-07-01

    Membrane proteins of the endoplasmic reticulum (ER) are involved in a wide array of essential cellular functions. Identification of the topology of membrane proteins can provide significant insight into their mechanisms of action and biological roles. This is particularly important for membrane enzymes, since their topology determines the subcellular site where a biochemical reaction takes place and the dependence on luminal or cytosolic co-factor pools and substrates. The methods currently available for the determination of topology of proteins are rather laborious and require post-lysis or post-fixation manipulation of cells. In this work, we have developed a simple method for defining intracellular localization and topology of ER membrane proteins in living cells, based on the fusion of the respective protein with redox-sensitive green-fluorescent protein (roGFP). We validated the method and demonstrated that roGFP fusion proteins constitute a reliable tool for the study of ER membrane protein topology, using as control microsomal 11β-hydroxysteroid dehydrogenase (11β-HSD) proteins whose topology has been resolved, and comparing with an independent approach. We then implemented this method to determine the membrane topology of six microsomal members of the 17β-hydroxysteroid dehydrogenase (17β-HSD) family. The results revealed a luminal orientation of the catalytic site for three enzymes, i.e. 17β-HSD6, 7 and 12. Knowledge of the intracellular location of the catalytic site of these enzymes will enable future studies on their biological functions and on the role of the luminal co-factor pool. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Detection of an unknown fusion protein in confiscated black market products.

    Science.gov (United States)

    Walpurgis, Katja; Krug, Oliver; Thomas, Andreas; Laussmann, Tim; Schänzer, Wilhelm; Thevis, Mario

    2014-01-01

    Even without clinical approval, many performance-enhancing drugs are available on the black market and can therefore be easily obtained by cheating athletes. The misuse of these preparations can be associated with unforeseeable health risks - either due to a poor quality of the drugs or as a result of an insufficient clinical assessment. Moreover, confiscated black market products have frequently been shown to contain ingredients other than those declared on the label as well as additional by-products or compounds with a modified molecular structure. This communication describes the identification of an unknown fusion protein observed in several unlabelled black market products obtained from independent sources. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of the confiscated preparations indicated the presence of an 18-kDa fusion protein consisting of the bacterial redox protein thioredoxin-1 (Trx, 12 kDa) and a 6-kDa peptide of unassigned composition. Trx has no relevance as performance enhancing agent but is routinely used as solubility tag for recombinant protein production. Further evaluation of the acquired MS/MS data revealed both an additional His tag and a thrombin cleavage site between the tags and the presumed bioactive peptide. However, thrombin cleavage of the fusion protein and LC-MS/MS analysis of the resulting peptide fragment finally suggested that the unknown protein is only the product of an empty expression vector without the DNA insert of interest. These findings are a further alarming example for the high level of risk that athletes take when misusing drugs obtained from the black market. Copyright © 2014 John Wiley & Sons, Ltd.

  5. The destructive effect of botulinum neurotoxins on the SNARE protein: SNAP-25 and synaptic membrane fusion

    Directory of Open Access Journals (Sweden)

    Bin Lu

    2015-06-01

    Full Text Available Synaptic exocytosis requires the assembly of syntaxin 1A and SNAP-25 on the plasma membrane and synaptobrevin 2 (VAMP2 on the vesicular membrane to bridge the two opposite membranes. It is believed that the three SNARE proteins assemble in steps along the dynamic assembly pathway. The C-terminus of SNAP-25 is known to be the target of botulinum neurotoxins (BoNT/A and BoNT/E that block neurotransmitters release in vivo. In this study, we employed electron paramagnetic resonance (EPR spectroscopy to investigate the conformation of the SNAP-25 C-terminus in binary and ternary SNARE complexes. The fluorescence lipid mixing assay shows that the C-terminal of SNAP-25 is essential for membrane fusion, and that the truncated SNAP-25 mutants cleaved by BoNT/A and BoNT/E display different inhibition effects on membrane fusion: SNAP-25E (Δ26 abolishes the fusion activity of the SNARE complex, while SNAP-25A (Δ9 loses most of its function, although it can still form a SDS-resistant SNARE complex as the wild-type SNAP-25. CW-EPR spectra validate the unstable structures of the SNARE complex formed by SNAP-25 mutants. We propose that the truncated SNAP-25 mutants will disrupt the assembly of the SNARE core complex, and then inhibit the synaptic membrane fusion accordingly.

  6. The Mesodermal Expression of rolling stone (rost) Is Essential for Myoblast Fusion in Drosophila and Encodes a Potential Transmembrane Protein

    OpenAIRE

    Paululat, Achim; Goubeaud, Anette; Damm, Christine; Knirr, Stefan; Burchard, Susanne; Renkawitz-Pohl, Renate

    1997-01-01

    In homozygous rolling stone embryos, the fusion of myoblasts to syncytial myotubes is diminished. Nevertheless, the visceral mesoderm, the heart mesoderm, and few somatic muscles are properly formed. Thus, we postulate a central role of rolling stone for the fusion process within the somatic mesoderm. We have cloned the rolling stone gene, and the deduced protein sequence is in accordance with a transmembrane protein, which agrees with the enrichment of Rost in the membrane fraction of Drosop...

  7. Expression of RecA and cell-penetrating peptide (CPP) fusion protein in bacteria and in mammalian cells.

    Science.gov (United States)

    Chang, Xiubao; Hou, Yuexian

    2018-01-01

    Genome editing is a powerful tool to modify a specific gene and to correct a disease-causing mutation. Recently developed new techniques, such as zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALEN) and clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9), significantly facilitate the progression in this field. However, mutations associated with the double strand DNA breaks (DSBs) introduced by these systems hampered their direct usage in clinic. In order to prevent the mutations caused by DSBs, we have designed a novel mean to induce homology-directed recombination (HDR) without DSBs, i.e., the fusion protein of RecA with cell-penetrating peptide (CPP). The involvement of RecA in these fusion proteins will play important roles in formation of the nucleoprotein filament with single strand DNA (ssDNA) in vitro and promoting HDR in vivo ; whereas the involvement of CPP in these fusion proteins will mainly play a role in facilitating cellular intake/uptake of the nucleoprotein filaments. Our results indicated that certain amount of the fusion proteins expressed in bacteria is in soluble fraction, whereas majority of the fusion proteins expressed in baby hamster kidney (BHK) cells is in soluble fraction. Interestingly, expression of these fusion proteins in bacteria completely blocked cell growth, whereas expression of them in BHK cells significantly inhibited cell growth, implying that these fusion proteins may bind to ssDNA regions, such as ssDNA regions in DNA replication forks, and inhibit cell growth. These results suggest that we have functional RecA.CPP fusion proteins ready to test our novel idea of inducing HDR without DSB.

  8. Effective strategies for host cell protein clearance in downstream processing of monoclonal antibodies and Fc-fusion proteins.

    Science.gov (United States)

    Li, Yifeng

    2017-06-01

    Recombinant therapeutic proteins are typically produced through cell culture process. Host cell proteins (HCPs) are endogenous proteins derived from the host cells used for such bioproduction. HCPs form a major class of process-related impurities and even at low levels they can potentially compromise the safety and efficacy of biopharmaceuticals. Therefore, they need to be adequately removed via the downstream process. HCPs are complex mixtures with diverse physiochemical properties, and certain subpopulations can bind to the intended product. Hence reducing them to the generally accepted level can be challenging. This article reviews effective HCP removing strategies at different stages of downstream process for monoclonal antibodies and Fc-fusion proteins. When used in combination, these strategies can greatly enhance the chance of meeting the drug substance specifications for residual HCP. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Effects of protein transduction domain (PTD) selection and position for improved intracellular delivery of PTD-Hsp27 fusion protein formulations.

    Science.gov (United States)

    Ul Ain, Qurrat; Lee, Jong Hwan; Woo, Young Sun; Kim, Yong-Hee

    2016-09-01

    Protein drugs have attracted considerable attention as therapeutic agents due to their diversity and biocompatibility. However, hydrophilic proteins possess difficulty in penetrating lipophilic cell membrane. Although protein transduction domains (PTDs) have shown effectiveness in protein delivery, the importance of selection and position of PTDs in recombinant protein vector constructs has not been investigated. This study intends to investigate the significance of PTD selection and position for therapeutic protein delivery. Heat shock protein 27 (Hsp27) would be a therapeutic protein for the treatment of ischemic heart diseases, but itself is insufficient to prevent systemic degradation and overcoming biochemical barriers during cellular transport. Among all PTD-Hsp27 fusion proteins we cloned, Tat-Hsp27 fusion protein showed the highest efficacy. Nona-arginine (9R) conjugation to the N-terminal of Hsp27 (Hsp27-T) showed higher efficacy than C-terminal. To test the synergistic effect of two PTDs, Tat was inserted to the N-terminal of Hsp27-9R. Tat-Hsp27-9R exhibited enhanced transduction efficiency and significant improvement against oxidative stress and apoptosis. PTD-Hsp27 fusion proteins have strong potential to be developed as therapeutic proteins for the treatment of ischemic heart diseases and selection and position of PTDs for improved efficacy of PTD-fusion proteins need to be optimized considering protein's nature, transduction efficiency and stability.

  10. Expression Screening of Fusion Partners from an E. coli Genome for Soluble Expression of Recombinant Proteins in a Cell-Free Protein Synthesis System

    OpenAIRE

    Ahn, Jin Ho; Keum, Jung-Won; Kim, Dong-Myung

    2011-01-01

    While access to soluble recombinant proteins is essential for a number of proteome studies, preparation of purified functional proteins is often limited by the protein solubility. In this study, potent solubility-enhancing fusion partners were screened from the repertoire of endogenous E. coli proteins. Based on the presumed correlation between the intracellular abundance and folding efficiency of proteins, PCR-amplified ORFs of a series of highly abundant E. coli proteins were fused with agg...

  11. Design of a single-chain multi-enzyme fusion protein establishing the polyhydroxybutyrate biosynthesis pathway.

    Science.gov (United States)

    Mullaney, Jane A; Rehm, Bernd H A

    2010-05-03

    Polyhydroxyalkanoates are biodegradable biocompatible polymers naturally produced by various bacteria and archaea. Biotechnological production in transgenic plants has already been demonstrated with efficient polyhydroxybutyrate production requiring targeting of the enzymes to the chloroplasts. Three enzymes are required to establish the polyhydroxybutyrate biosynthesis pathway in non-naturally producing microorganisms or plants. To facilitate production of biopolyesters in plants, a gene encoding a translational fusion of the polyhydroxybutyrate biosynthesis enzymes PhaA (beta-ketothiolase), PhaB (acetoacetyl-CoA reductase) and PhaC (PHA synthase) was constructed. Escherichia coli harboring a plasmid encoding this fusion protein (PhaA-PhaB-PhaC) under control of the lac promoter accumulated polyhydroxybutyrate contributing to 0.4% (w/w) of cellular dry weight. Insertion of an extended linker between PhaA and PhaB increased polyhydroxybutyrate accumulation to 3.9% (w/w) of cellular dry weight. Introduction of a second plasmid encoding PhaA and PhaB restored polyhydroxybutyrate accumulation to wildtype levels of about 35% (w/w) of cellular dry weight suggesting that the functions of PhaA and/or PhaB were limiting factors. Deletion of PhaA in trans led to significantly reduced polyhydroxybutyrate production suggesting that the PhaA activity in the fusion protein is reduced. This study showed that a single-chain translational fusion protein comprising the three enzymes essential for polyhydroxybutyrate synthesis can be engineered which will strongly facilitate the establishment of recombinant polyhydroxybutyrate production organisms particularly requiring targeting to sub-cellular compartments such as the chloroplasts in plants. 2010 Elsevier B.V. All rights reserved.

  12. Prokaryotic ubiquitin-like ThiS fusion enhances the heterologous protein overexpression and aggregation in Escherichia coli.

    Science.gov (United States)

    Yuan, Sujuan; Xu, Jian; Ge, Ying; Yan, Zheng; Du, Guohua; Wang, Nan

    2013-01-01

    Fusion tags are commonly employed to enhance target protein expression, improve their folding and solubility, and reduce protein degradation in expression of recombinant proteins. Ubiquitin (Ub) and SUMO are highly conserved small proteins in eukaryotes, and frequently used as fusion tags in prokaryotic expression. ThiS, a smaller sulfur-carrier protein involved in thiamin synthesis, is conserved among most prokaryotic species. The structural similarity between ThiS and Ub provoked us into expecting that the former could be used as a fusion tag. Hence, ThiS was fused to insulin A and B chains, murine Ribonuclease Inhibitor (mRI) and EGFP, respectively. When induced in Escherichia coli, ThiS-fused insulin A and B chains were overexpressed in inclusion bodies, and to higher levels in comparison to the same proteins fused with Ub. On the contrast, ThiS fusion of mRI, an unstable protein, resulted in enhanced degradation that was not alleviated in protease-deficient strains. While the degradation of Ub- and SUMO-fused mRI was less and seemed protease-dependent. Enhanced degradation of mRI did not occur for the fusions with half-molecules of ThiS. When ThiS-tag was fused to the C-terminus of EGFP, higher expression, predominantly in inclusion bodies, was observed again. It was further found that ThiS fusion of EGFP significantly retarded its refolding process. These results indicated that prokaryotic ThiS is able to promote the expression of target proteins in E. coli, but enhanced degradation may occur in case of unstable targets. Unlike eukaryotic Ub-based tags usually increase the solubility and folding of proteins, ThiS fusion enhances the expression by augmenting the formation of inclusion bodies, probably through retardation of the folding of target proteins.

  13. Protein interaction maps for complete genomes based on gene fusion events

    Science.gov (United States)

    Enright, Anton J.; Iliopoulos, Ioannis; Kyrpides, Nikos C.; Ouzounis, Christos A.

    1999-11-01

    A large-scale effort to measure, detect and analyse protein-protein interactions using experimental methods is under way. These include biochemistry such as co-immunoprecipitation or crosslinking, molecular biology such as the two-hybrid system or phage display, and genetics such as unlinked noncomplementing mutant detection. Using the two-hybrid system, an international effort to analyse the complete yeast genome is in progress. Evidently, all these approaches are tedious, labour intensive and inaccurate. From a computational perspective, the question is how can we predict that two proteins interact from structure or sequence alone. Here we present a method that identifies gene-fusion events in complete genomes, solely based on sequence comparison. Because there must be selective pressure for certain genes to be fused over the course of evolution, we are able to predict functional associations of proteins. We show that 215 genes or proteins in the complete genomes of Escherichia coli, Haemophilus influenzae and Methanococcus jannaschii are involved in 64 unique fusion events. The approach is general, and can be applied even to genes of unknown function.

  14. Two single mutations in the fusion protein of Newcastle disease virus confer hemagglutinin-neuraminidase independent fusion promotion and attenuate the pathogenicity in chickens.

    Science.gov (United States)

    Ji, Yanhong; Liu, Tao; Jia, Yane; Liu, Bin; Yu, Qingzhong; Cui, Xiaole; Guo, Fengfeng; Chang, Huiyun; Zhu, Qiyun

    2017-09-01

    The fusion (F) protein of Newcastle disease virus (NDV) affects viral infection and pathogenicity through mediating membrane fusion. Previously, we found NDV with increased fusogenic activity in which contained T458D or G459D mutation in the F protein. Here, we investigated the effects of these two mutations on viral infection, fusogenicity and pathogenicity. Syncytium formation assays indicated that T458D or G459D increased the F protein cleavage activity and enhanced cell fusion with or without the presence of HN protein. The T458D- or G459D-mutated NDV resulted in a decrease in virus replication or release from cells. The animal study showed that the pathogenicity of the mutated NDVs was attenuated in chickens. These results indicate that these two single mutations in F altered or diminished the requirement of HN for promoting membrane fusion. The increased fusogenic activity may disrupt the cellular machinery and consequently decrease the virus replication and pathogenicity in chickens. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. The hTAF II 68-TEC fusion protein functions as a strong transcriptional activator.

    Science.gov (United States)

    Kim, Sol; Lee, Hye Jin; Jun, Hee Jung; Kim, Jungho

    2008-06-01

    Human extraskeletal myxoid chondrosarcoma (EMC) is caused by a chromosomal translocation that involves TEC (translocated in extraskeletal myxoid chondrosarcoma), and either EWS (Ewing's sarcoma) or hTAF(II)68 (human TATA-binding protein-associated factor II 68), which generates EWS-TEC or hTAF(II)68-TEC fusion proteins, respectively. Although there has been a great deal of progress in characterizing EWS-TEC, there is relatively little known about the biological function of hTAF(II)68-TEC. We have examined the functional consequences of the fusion of the amino terminal domain (NTD) of hTAF(II)68 to TEC in EMC. The chimeric gene encodes a nuclear protein that binds DNA with the same sequence specificity as parental TEC. Nuclear localization of hTAF(II)68-TEC was dependent on the DNA binding domain, and we identified a cluster of basic amino acids in the DNA binding domain, KRRR, that specifically mediate the nuclear localization of hTAF(II)68-TEC. The transactivation activity of hTAF(II)68-TEC was higher than TEC towards a known target promoter that contained several TEC binding sites. Finally, deletion analysis of hTAF(II)68-TEC indicated that the hTAF(II)68 NTD, and the AF1 and AF2 domains of hTAF(II)68-TEC are necessary for full transactivation potential. These results suggest that the oncogenic effect of the t(9;17) translocation may be due to the hTAF(II)68-TEC chimeric protein and that fusion of the hTAF(II)68 NTD to the TEC protein produces a gain of function chimeric product. (c) 2008 Wiley-Liss, Inc.

  16. Eradication of Human Hepatic and Pulmonary Melanoma Metastases in SCID Mice by Antibody--Interleukin 2 Fusion Proteins

    Science.gov (United States)

    Becker, Jurgen C.; Pancook, James D.; Gillies, Stephen D.; Mendelsohn, John; Reisfeld, Ralph A.

    1996-04-01

    Antibody--cytokine fusion proteins combine the unique targeting ability of antibodies with the multifunctional activity of cytokines. Here, we demonstrate the therapeutic efficacy of such constructs for the treatment of hepatic and pulmonary metastases of different melanoma cell lines. Two antibody--interleukin 2 (IL-2) fusion proteins, ch225-IL2 and ch14.18-IL2, constructed by fusion of a synthetic sequence coding for human IL-2 to the carboxyl end of the Cγ 1 gene of the corresponding antibodies, were tested for their therapeutic efficacy against xenografted human melanoma in vivo. Tumorspecific fusion proteins completely inhibited the growth of hepatic and pulmonary metastases in C.B-17 scid/scid mice previously reconstituted with human lymphokine-activated killer cells, whereas treatment with combinations of the corresponding antibodies plus recombinant IL-2 only reduced the tumor load. Even when treatment with fusion proteins was delayed up to 8 days after inoculation of tumor cells, it still resulted in complete eradication of micrometastases that were established at that time point. Selection of tumor cell lines expressing or lacking the targeted antigen of the administered fusion protein proved the specificity of the observed antitumor effect. Biodistribution analysis demonstrated that the tumorspecific fusion protein accumulated not only in subcutaneous tumors but also in lungs and livers affected with micrometastases. Survival times of animals treated with the fusion protein were more than doubled as compared to those treated with the combination of the corresponding antibody plus IL-2. Our data demonstrate that an immunotherapeutic approach using cytokines targeted by antibodies to tumor sites has potent effects against disseminated human melanoma.

  17. A plasmid toolkit for cloning chimeric cDNAs encoding customized fusion proteins into any Gateway destination expression vector.

    Science.gov (United States)

    Buj, Raquel; Iglesias, Noa; Planas, Anna M; Santalucía, Tomàs

    2013-08-20

    Valuable clone collections encoding the complete ORFeomes for some model organisms have been constructed following the completion of their genome sequencing projects. These libraries are based on Gateway cloning technology, which facilitates the study of protein function by simplifying the subcloning of open reading frames (ORF) into any suitable destination vector. The expression of proteins of interest as fusions with functional modules is a frequent approach in their initial functional characterization. A limited number of Gateway destination expression vectors allow the construction of fusion proteins from ORFeome-derived sequences, but they are restricted to the possibilities offered by their inbuilt functional modules and their pre-defined model organism-specificity. Thus, the availability of cloning systems that overcome these limitations would be highly advantageous. We present a versatile cloning toolkit for constructing fully-customizable three-part fusion proteins based on the MultiSite Gateway cloning system. The fusion protein components are encoded in the three plasmids integral to the kit. These can recombine with any purposely-engineered destination vector that uses a heterologous promoter external to the Gateway cassette, leading to the in-frame cloning of an ORF of interest flanked by two functional modules. In contrast to previous systems, a third part becomes available for peptide-encoding as it no longer needs to contain a promoter, resulting in an increased number of possible fusion combinations. We have constructed the kit's component plasmids and demonstrate its functionality by providing proof-of-principle data on the expression of prototype fluorescent fusions in transiently-transfected cells. We have developed a toolkit for creating fusion proteins with customized N- and C-term modules from Gateway entry clones encoding ORFs of interest. Importantly, our method allows entry clones obtained from ORFeome collections to be used without prior

  18. Dimeric and Trimeric Fusion Proteins Generated with Fimbrial Adhesins of UropathogenicEscherichia coli.

    Science.gov (United States)

    Luna-Pineda, Víctor M; Reyes-Grajeda, Juan Pablo; Cruz-Córdova, Ariadnna; Saldaña-Ahuactzi, Zeus; Ochoa, Sara A; Maldonado-Bernal, Carmen; Cázares-Domínguez, Vicenta; Moreno-Fierros, Leticia; Arellano-Galindo, José; Hernández-Castro, Rigoberto; Xicohtencatl-Cortes, Juan

    2016-01-01

    Urinary tract infections (UTIs) are associated with high rates of morbidity and mortality worldwide, and uropathogenic Escherichia coli (UPEC) is the main etiologic agent. Fimbriae assembled on the bacterial surface are essential for adhesion to the urinary tract epithelium. In this study, the FimH, CsgA, and PapG adhesins were fused to generate biomolecules for use as potential target vaccines against UTIs. The fusion protein design was generated using bioinformatics tools, and template fusion gene sequences were synthesized by GenScript in the following order fimH - csgA - papG - fimH - csgA ( fcpfc ) linked to the nucleotide sequence encoding the [EAAAK] 5 peptide. Monomeric ( fimH, csgA , and papG ), dimeric ( fimH-csgA ), and trimeric ( fimH - csgA - papG ) genes were cloned into the pLATE31 expression vector and generated products of 1040, 539, 1139, 1442, and 2444 bp, respectively. Fusion protein expression in BL21 E. coli was induced with 1 mM IPTG, and His-tagged proteins were purified under denaturing conditions and refolded by dialysis using C-buffer. Coomassie blue-stained SDS-PAGE gels and Western blot analysis revealed bands of 29.5, 11.9, 33.9, 44.9, and 82.1 kDa, corresponding to FimH, CsgA, PapG, FC, and FCP proteins, respectively. Mass spectrometry analysis by MALDI-TOF/TOF revealed specific peptides that confirmed the fusion protein structures. Dynamic light scattering analysis revealed the polydispersed state of the fusion proteins. FimH, CsgA, and PapG stimulated the release of 372-398 pg/mL IL-6; interestingly, FC and FCP stimulated the release of 464.79 pg/mL ( p ≤ 0.018) and 521.24 pg/mL ( p ≤ 0.002) IL-6, respectively. In addition, FC and FCP stimulated the release of 398.52 pg/mL ( p ≤ 0.001) and 450.40 pg/mL ( p ≤ 0.002) IL-8, respectively. High levels of IgA and IgG antibodies in human sera reacted against the fusion proteins, and under identical conditions, low levels of IgA and IgG antibodies were detected in human urine

  19. Chemotropism and Cell Fusion in Neurospora crassa Relies on the Formation of Distinct Protein Complexes by HAM-5 and a Novel Protein HAM-14.

    Science.gov (United States)

    Jonkers, Wilfried; Fischer, Monika S; Do, Hung P; Starr, Trevor L; Glass, N Louise

    2016-05-01

    In filamentous fungi, communication is essential for the formation of an interconnected, multinucleate, syncytial network, which is constructed via hyphal fusion or fusion of germinated asexual spores (germlings). Anastomosis in filamentous fungi is comparable to other somatic cell fusion events resulting in syncytia, including myoblast fusion during muscle differentiation, macrophage fusion, and fusion of trophoblasts during placental development. In Neurospora crassa, fusion of genetically identical germlings is a highly dynamic and regulated process that requires components of a MAP kinase signal transduction pathway. The kinase pathway components (NRC-1, MEK-2 and MAK-2) and the scaffold protein HAM-5 are recruited to hyphae and germling tips undergoing chemotropic interactions. The MAK-2/HAM-5 protein complex shows dynamic oscillation to hyphae/germling tips during chemotropic interactions, and which is out-of-phase to the dynamic localization of SOFT, which is a scaffold protein for components of the cell wall integrity MAP kinase pathway. In this study, we functionally characterize HAM-5 by generating ham-5 truncation constructs and show that the N-terminal half of HAM-5 was essential for function. This region is required for MAK-2 and MEK-2 interaction and for correct cellular localization of HAM-5 to "fusion puncta." The localization of HAM-5 to puncta was not perturbed in 21 different fusion mutants, nor did these puncta colocalize with components of the secretory pathway. We also identified HAM-14 as a novel member of the HAM-5/MAK-2 pathway by mining MAK-2 phosphoproteomics data. HAM-14 was essential for germling fusion, but not for hyphal fusion. Colocalization and coimmunoprecipitation data indicate that HAM-14 interacts with MAK-2 and MEK-2 and may be involved in recruiting MAK-2 (and MEK-2) to complexes containing HAM-5. Copyright © 2016 by the Genetics Society of America.

  20. Coating Nanoparticles with Plant-Produced Transferrin-Hydrophobin Fusion Protein Enhances Their Uptake in Cancer Cells.

    Science.gov (United States)

    Reuter, Lauri J; Shahbazi, Mohammad-Ali; Mäkilä, Ermei M; Salonen, Jarno J; Saberianfar, Reza; Menassa, Rima; Santos, Hélder A; Joensuu, Jussi J; Ritala, Anneli

    2017-06-21

    The encapsulation of drugs to nanoparticles may offer a solution for targeted delivery. Here, we set out to engineer a self-assembling targeting ligand by combining the functional properties of human transferrin and fungal hydrophobins in a single fusion protein. We showed that human transferrin can be expressed in Nicotiana benthamiana plants as a fusion with Trichoderma reesei hydrophobins HFBI, HFBII, or HFBIV. Transferrin-HFBIV was further expressed in tobacco BY-2 suspension cells. Both partners of the fusion protein retained their functionality; the hydrophobin moiety enabled migration to a surfactant phase in an aqueous two-phase system, and the transferrin moiety was able to reversibly bind iron. Coating porous silicon nanoparticles with the fusion protein resulted in uptake of the nanoparticles in human cancer cells. This study provides a proof-of-concept for the functionalization of hydrophobin coatings with transferrin as a targeting ligand.

  1. Salmonella flagellin acted as an effective fusion partner for expression of Plasmodium falciparum surface protein 25 in Escherichia coli.

    Science.gov (United States)

    Qian, Feng; Li, Mengmeng; Chen, Yong; Jiang, Lin; Xu, Huji

    2016-09-01

    Plasmodium falciparum surface protein 25 (Pfs25) is a hard-to-express and hard-to-solubilize protein in Escherichia coli. To overcome this problem, the phase 1 flagellin of Salmonella enterica serovar Typhimurium (FliC) was used as a fusion partner for Pfs25. The fusion expression of Pfs25 with FliC greatly enhanced the expression level and solubility of Pfs25 in E. coli BL21(DE3). The Ni-purified fusion protein of FliC-Pfs25 was recognized by two anti-Pfs25 monoclonal antibodies. By comparison, it was shown that the Pfs25 within FliC-Pfs25 contained epitopes similar or identical to those on Pichia pastoris-produced Pfs25. The data obtained from this study demonstrated that the fusion with Salmonella flagellin greatly improved the expression of Pfs25 in E. coli.

  2. Characterization of Aggregation Propensity of a Human Fc-Fusion Protein Therapeutic by Hydrogen/Deuterium Exchange Mass Spectrometry

    Science.gov (United States)

    Huang, Richard Y.-C.; Iacob, Roxana E.; Krystek, Stanley R.; Jin, Mi; Wei, Hui; Tao, Li; Das, Tapan K.; Tymiak, Adrienne A.; Engen, John R.; Chen, Guodong

    2017-05-01

    Aggregation of protein therapeutics has long been a concern across different stages of manufacturing processes in the biopharmaceutical industry. It is often indicative of aberrant protein therapeutic higher-order structure. In this study, the aggregation propensity of a human Fc-fusion protein therapeutic was characterized. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) was applied to examine the conformational dynamics of dimers collected from a bioreactor. HDX-MS data combined with spatial aggregation propensity calculations revealed a potential aggregation interface in the Fc domain. This study provides a general strategy for the characterization of the aggregation propensity of Fc-fusion proteins at the molecular level.

  3. Intrafocal heterogeneity of ERG protein expression and gene fusion pattern in prostate cancer.

    Science.gov (United States)

    Suh, Ja Hee; Park, Jeong Hwan; Lee, Cheol; Moon, Kyung Chul

    2017-10-01

    Prostate cancer is considered to be highly heterogeneous, with various morphologic features and biologic behaviors. The TMPRSS2-ERG gene fusion is the most frequently observed genetic aberration in prostate cancer. The aim of this study was to elucidate the intrafocal heterogeneity of ERG gene fusion status. ERG immunohistochemistry (IHC) was performed in samples from 168 prostate cancer patients who had undergone radical prostatectomy, and 40 cases showing ERG-positive IHC staining were selected for tissue microarray (TMA) construction. Two to six representative cores were selected from each tumor focus. In the cases with heterogeneous ERG IHC staining intensity, the areas showing different intensities were separately selected. Using the TMA blocks, IHC and fluorescence in situ hybridization (FISH) were conducted to evaluate the heterogeneity of ERG protein expression and ERG fusion gene patterns, respectively, in a single tumor focus. Heterogeneity of ERG IHC staining was defined as the simultaneous presence of negative and positive cores in the same tumor focus. Heterogeneity of ERG FISH was defined by the presence of cores with positive and negative FISH signals or cores with break-apart and interstitial deletion FISH signals in the same tumor focus. A total of 202 TMA cores were isolated from 40 ERG-positive cases. Of the 202 total cores, 19 were negative for ERG IHC staining, and 46 showed 1+, 52 showed 2+, and 85 showed 3+ ERG staining intensity. Eleven cores were negative for ERG FISH signal, 119 cores showed ERG break-apart FISH signals, and the remaining 72 cores revealed interstitial deletion. Intrafocal heterogeneity of ERG IHC staining was found in 20% (8/40) of cases, and intrafocal heterogeneity of ERG gene fusion pattern was found in 32.5% (13/40) of cases. In summary, this study showed significantly frequent intrafocal heterogeneity of ERG protein expression, gene fusion status and fusion pattern. This heterogeneity can be caused by the development

  4. Protein Sub-Nuclear Localization Based on Effective Fusion Representations and Dimension Reduction Algorithm LDA

    Directory of Open Access Journals (Sweden)

    Shunfang Wang

    2015-12-01

    Full Text Available An effective representation of a protein sequence plays a crucial role in protein sub-nuclear localization. The existing representations, such as dipeptide composition (DipC, pseudo-amino acid composition (PseAAC and position specific scoring matrix (PSSM, are insufficient to represent protein sequence due to their single perspectives. Thus, this paper proposes two fusion feature representations of DipPSSM and PseAAPSSM to integrate PSSM with DipC and PseAAC, respectively. When constructing each fusion representation, we introduce the balance factors to value the importance of its components. The optimal values of the balance factors are sought by genetic algorithm. Due to the high dimensionality of the proposed representations, linear discriminant analysis (LDA is used to find its important low dimensional structure, which is essential for classification and location prediction. The numerical experiments on two public datasets with KNN classifier and cross-validation tests showed that in terms of the common indexes of sensitivity, specificity, accuracy and MCC, the proposed fusing representations outperform the traditional representations in protein sub-nuclear localization, and the representation treated by LDA outperforms the untreated one.

  5. Protein Sub-Nuclear Localization Based on Effective Fusion Representations and Dimension Reduction Algorithm LDA.

    Science.gov (United States)

    Wang, Shunfang; Liu, Shuhui

    2015-12-19

    An effective representation of a protein sequence plays a crucial role in protein sub-nuclear localization. The existing representations, such as dipeptide composition (DipC), pseudo-amino acid composition (PseAAC) and position specific scoring matrix (PSSM), are insufficient to represent protein sequence due to their single perspectives. Thus, this paper proposes two fusion feature representations of DipPSSM and PseAAPSSM to integrate PSSM with DipC and PseAAC, respectively. When constructing each fusion representation, we introduce the balance factors to value the importance of its components. The optimal values of the balance factors are sought by genetic algorithm. Due to the high dimensionality of the proposed representations, linear discriminant analysis (LDA) is used to find its important low dimensional structure, which is essential for classification and location prediction. The numerical experiments on two public datasets with KNN classifier and cross-validation tests showed that in terms of the common indexes of sensitivity, specificity, accuracy and MCC, the proposed fusing representations outperform the traditional representations in protein sub-nuclear localization, and the representation treated by LDA outperforms the untreated one.

  6. Resolution of Disulfide Heterogeneity in Nogo Receptor 1 Fusion Proteins by Molecular Engineering

    Energy Technology Data Exchange (ETDEWEB)

    P Weinreb; D Wen; F Qian; C Wildes; E Garber; L Walus; M Jung; J Wang; J Relton; et al.

    2011-12-31

    NgRI (Nogo-66 receptor) is part of a signalling complex that inhibits axon regeneration in the central nervous system. Truncated soluble versions of NgRI have been used successfully to promote axon regeneration in animal models of spinal-cord injury, raising interest in this protein as a potential therapeutic target. The LRR (leucine-rich repeat) regions in NgRI are flanked by N- and C-terminal disulfide-containing 'cap' domains (LRRNT and LRRCT respectively). In the present work we show that, although functionally active, the NgRI(310)-Fc fusion protein contains mislinked and heterogeneous disulfide patterns in the LRRCT domain, and we report the generation of a series of variant molecules specifically designed to prevent this heterogeneity. Using these variants we explored the effects of modifying the NgRI truncation site or the spacing between the NgRI and Fc domains, or replacing cysteines within the NgRI or IgG hinge regions. One variant, which incorporates replacements of Cys{sup 266} and Cys{sup 309} with alanine residues, completely eliminated disulfide scrambling while maintaining functional in vitro and in vivo efficacy. This modified NgRI-Fc molecule represents a significantly improved candidate for further pharmaceutical development, and may serve as a useful model for the optimization of other IgG fusion proteins made from LRR proteins.

  7. Transposon assisted gene insertion technology (TAGIT: a tool for generating fluorescent fusion proteins.

    Directory of Open Access Journals (Sweden)

    James A Gregory

    2010-01-01

    Full Text Available We constructed a transposon (transposon assisted gene insertion technology, or TAGIT that allows the random insertion of gfp (or other genes into chromosomal loci without disrupting operon structure or regulation. TAGIT is a modified Tn5 transposon that uses Kan(R to select for insertions on the chromosome or plasmid, beta-galactosidase to identify in-frame gene fusions, and Cre recombinase to excise the kan and lacZ genes in vivo. The resulting gfp insertions maintain target gene reading frame (to the 5' and 3' of gfp and are integrated at the native chromosomal locus, thereby maintaining native expression signals. Libraries can be screened to identify GFP insertions that maintain target protein function at native expression levels, allowing more trustworthy localization studies. We here use TAGIT to generate a library of GFP insertions in the Escherichia coli lactose repressor (LacI. We identified fully functional GFP insertions and partially functional insertions that bind DNA but fail to repress the lacZ operon. Several of these latter GFP insertions localize to lacO arrays integrated in the E. coli chromosome without producing the elongated cells frequently observed when functional LacI-GFP fusions are used in chromosome tagging experiments. TAGIT thereby faciliates the isolation of fully functional insertions of fluorescent proteins into target proteins expressed from the native chromosomal locus as well as potentially useful partially functional proteins.

  8. Mitochondrial remodeling following fission inhibition by 15d-PGJ2 involves molecular changes in mitochondrial fusion protein OPA1

    International Nuclear Information System (INIS)

    Kar, Rekha; Mishra, Nandita; Singha, Prajjal K.; Venkatachalam, Manjeri A.; Saikumar, Pothana

    2010-01-01

    Research highlights: → Chemical inhibition of fission protein Drp1 leads to mitochondrial fusion. → Increased fusion stimulates molecular changes in mitochondrial fusion protein OPA1. → Proteolysis of larger isoforms, new synthesis and ubiquitination of OPA1 occur. → Loss of mitochondrial tubular rigidity and disorganization of cristae. → Generation of large swollen dysfunctional mitochondria. -- Abstract: We showed earlier that 15 deoxy Δ 12,14 prostaglandin J2 (15d-PGJ2) inactivates Drp1 and induces mitochondrial fusion . However, prolonged incubation of cells with 15d-PGJ2 resulted in remodeling of fused mitochondria into large swollen mitochondria with irregular cristae structure. While initial fusion of mitochondria by 15d-PGJ2 required the presence of both outer (Mfn1 and Mfn2) and inner (OPA1) mitochondrial membrane fusion proteins, later mitochondrial changes involved increased degradation of the fusion protein OPA1 and ubiquitination of newly synthesized OPA1 along with decreased expression of Mfn1 and Mfn2, which likely contributed to the loss of tubular rigidity, disorganization of cristae, and formation of large swollen degenerated dysfunctional mitochondria. Similar to inhibition of Drp1 by 15d-PGJ2, decreased expression of fission protein Drp1 by siRNA also resulted in the loss of fusion proteins. Prevention of 15d-PGJ2 induced mitochondrial elongation by thiol antioxidants prevented not only loss of OPA1 isoforms but also its ubiquitination. These findings provide novel insights into unforeseen complexity of molecular events that modulate mitochondrial plasticity.

  9. Expression screening of fusion partners from an E. coli genome for soluble expression of recombinant proteins in a cell-free protein synthesis system.

    Science.gov (United States)

    Ahn, Jin-Ho; Keum, Jung-Won; Kim, Dong-Myung

    2011-01-01

    While access to soluble recombinant proteins is essential for a number of proteome studies, preparation of purified functional proteins is often limited by the protein solubility. In this study, potent solubility-enhancing fusion partners were screened from the repertoire of endogenous E. coli proteins. Based on the presumed correlation between the intracellular abundance and folding efficiency of proteins, PCR-amplified ORFs of a series of highly abundant E. coli proteins were fused with aggregation-prone heterologous proteins and then directly expressed for quantitative estimation of the expression efficiency of soluble translation products. Through two-step screening procedures involving the expression of 552 fusion constructs targeted against a series of cytokine proteins, we were able to discover a number of endogenous E. coli proteins that dramatically enhanced the soluble expression of the target proteins. This strategy of cell-free expression screening can be extended to quantitative, global analysis of genomic resources for various purposes.

  10. Optimization of the Expression of DT386-BR2 Fusion Protein in Escherichia coli using Response Surface Methodology.

    Science.gov (United States)

    Shafiee, Fatemeh; Rabbani, Mohammad; Jahanian-Najafabadi, Ali

    2017-01-01

    The aim of this study was to determine the best condition for the production of DT386-BR2 fusion protein, an immunotoxin consisting of catalytic and translocation domains of diphtheria toxin fused to BR2, a cancer specific cell penetrating peptide, for targeted eradication of cancer cells, in terms of the host, cultivation condition, and culture medium. Recombinant pET28a vector containing the codons optimized for the expression of the DT386-BR2 gene was transformed to different strains of Escherichia coli ( E. coli BL21 DE3, E. coli Rosetta DE3 and E. coli Rosetta-gami 2 DE3), followed by the induction of expression using 1 mM IPTG. Then, the strain with the highest ability to produce recombinant protein was selected and used to determine the best expression condition using response surface methodology (RSM). Finally, the best culture medium was selected. Densitometry analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the expressed fusion protein showed that E. coli Rosetta DE3 produced the highest amounts of the recombinant fusion protein when quantified by 1 mg/ml bovine serum albumin (178.07 μg/ml). Results of RSM also showed the best condition for the production of the recombinant fusion protein was induction with 1 mM IPTG for 2 h at 37°C. Finally, it was established that terrific broth could produce higher amounts of the fusion protein when compared to other culture media. In this study, we expressed the recombinant DT386-BR2 fusion protein in large amounts by optimizing the expression host, cultivation condition, and culture medium. This fusion protein will be subjected to purification and evaluation of its cytotoxic effects in future studies.

  11. Optimization of the Expression of DT386-BR2 Fusion Protein in Escherichia coli using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Fatemeh Shafiee

    2017-01-01

    Full Text Available Background: The aim of this study was to determine the best condition for the production of DT386-BR2 fusion protein, an immunotoxin consisting of catalytic and translocation domains of diphtheria toxin fused to BR2, a cancer specific cell penetrating peptide, for targeted eradication of cancer cells, in terms of the host, cultivation condition, and culture medium. Materials and Methods: Recombinant pET28a vector containing the codons optimized for the expression of the DT386-BR2 gene was transformed to different strains of Escherichia coli (E. coli BL21 DE3, E. coli Rosetta DE3 and E. coli Rosetta-gami 2 DE3, followed by the induction of expression using 1 mM IPTG. Then, the strain with the highest ability to produce recombinant protein was selected and used to determine the best expression condition using response surface methodology (RSM. Finally, the best culture medium was selected. Results: Densitometry analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the expressed fusion protein showed that E. coli Rosetta DE3 produced the highest amounts of the recombinant fusion protein when quantified by 1 mg/ml bovine serum albumin (178.07 μg/ml. Results of RSM also showed the best condition for the production of the recombinant fusion protein was induction with 1 mM IPTG for 2 h at 37°C. Finally, it was established that terrific broth could produce higher amounts of the fusion protein when compared to other culture media. Conclusion: In this study, we expressed the recombinant DT386-BR2 fusion protein in large amounts by optimizing the expression host, cultivation condition, and culture medium. This fusion protein will be subjected to purification and evaluation of its cytotoxic effects in future studies.

  12. Intracellular delivery of cell-penetrating peptide-transcriptional factor fusion protein and its role in selective osteogenesis

    Science.gov (United States)

    Suh, Jin Sook; Lee, Jue Yeon; Choi, Yoon Jung; You, Hyung Keun; Hong, Seong-Doo; Chung, Chong Pyoung; Park, Yoon Jeong

    2014-01-01

    Protein-transduction technology has been attempted to deliver macromolecular materials, including protein, nucleic acids, and polymeric drugs, for either diagnosis or therapeutic purposes. Herein, fusion protein composed of an arginine-rich cell-penetrating peptide, termed low-molecular-weight protamine (LMWP), and a transcriptional coactivator with a PDZ-binding motif (TAZ) protein was prepared and applied in combination with biomaterials to increase bone-forming capacity. TAZ has been recently identified as a specific osteogenic stimulating transcriptional coactivator in human mesenchymal stem cell (hMSC) differentiation, while simultaneously blocking adipogenic differentiation. However, TAZ by itself cannot penetrate the cells, and thus needs a transfection tool for translocalization. The LMWP-TAZ fusion proteins were efficiently translocalized into the cytosol of hMSCs. The hMSCs treated with cell-penetrating LMWP-TAZ exhibited increased expression of osteoblastic genes and protein, producing significantly higher quantities of mineralized matrix compared to free TAZ. In contrast, adipogenic differentiation of the hMSCs was blocked by treatment of LMWP-TAZ fusion protein, as reflected by reduced marker-protein expression, adipocyte fatty acid-binding protein 2, and peroxisome proliferator-activated receptor-γ messenger ribonucleic acid levels. LMWP-TAZ was applied in alginate gel for the purpose of localization and controlled release. The LMWP-TAZ fusion protein-loaded alginate gel matrix significantly increased bone formation in rabbit calvarial defects compared with alginate gel matrix mixed with free TAZ protein. The protein transduction of TAZ fused with cell-penetrating LMWP peptide was able selectively to stimulate osteogenesis in vitro and in vivo. Taken together, this fusion protein-transduction technology for osteogenic protein can thus be applied in combination with biomaterials for tissue regeneration and controlled release for tissue

  13. Relationship between the loss of neutralizing antibody binding and fusion activity of the F protein of human respiratory syncytial virus

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    Sarisky Robert T

    2007-07-01

    Full Text Available Abstract To elucidate the relationship between resistance to HRSV neutralizing antibodies directed against the F protein and the fusion activity of the F protein, a recombinant approach was used to generate a panel of mutations in the major antigenic sites of the F protein. These mutant proteins were assayed for neutralizing mAb binding (ch101F, palivizumab, and MAb19, level of expression, post-translational processing, cell surface expression, and fusion activity. Functional analysis of the fusion activity of the panel of mutations revealed that the fusion activity of the F protein is tolerant to multiple changes in the site II and IV/V/VI region in contrast with the somewhat limited spectrum of changes in the F protein identified from the isolation of HRSV neutralizing antibody virus escape mutants. This finding suggests that aspects other than fusion activity may limit the spectrum of changes tolerated within the F protein that are selected for by neutralizing antibodies.

  14. Prm3p is a pheromone-induced peripheral nuclear envelope protein required for yeast nuclear fusion.

    Science.gov (United States)

    Shen, Shu; Tobery, Cynthia E; Rose, Mark D

    2009-05-01

    Nuclear membrane fusion is the last step in the mating pathway of the yeast Saccharomyces cerevisiae. We adapted a bioinformatics approach to identify putative pheromone-induced membrane proteins potentially required for nuclear membrane fusion. One protein, Prm3p, was found to be required for nuclear membrane fusion; disruption of PRM3 caused a strong bilateral defect, in which nuclear congression was completed but fusion did not occur. Prm3p was localized to the nuclear envelope in pheromone-responding cells, with significant colocalization with the spindle pole body in zygotes. A previous report, using a truncated protein, claimed that Prm3p is localized to the inner nuclear envelope. Based on biochemistry, immunoelectron microscopy and live cell microscopy, we find that functional Prm3p is a peripheral membrane protein exposed on the cytoplasmic face of the outer nuclear envelope. In support of this, mutations in a putative nuclear localization sequence had no effect on full-length protein function or localization. In contrast, point mutations and deletions in the highly conserved hydrophobic carboxy-terminal domain disrupted both protein function and localization. Genetic analysis, colocalization, and biochemical experiments indicate that Prm3p interacts directly with Kar5p, suggesting that nuclear membrane fusion is mediated by a protein complex.

  15. Respiratory syncytial virus fusion protein promotes TLR-4-dependent neutrophil extracellular trap formation by human neutrophils.

    Directory of Open Access Journals (Sweden)

    Giselle A Funchal

    Full Text Available Acute viral bronchiolitis by Respiratory Syncytial Virus (RSV is the most common respiratory illness in children in the first year of life. RSV bronchiolitis generates large numbers of hospitalizations and an important burden to health systems. Neutrophils and their products are present in the airways of RSV-infected patients who developed increased lung disease. Neutrophil Extracellular Traps (NETs are formed by the release of granular and nuclear contents of neutrophils in the extracellular space in response to different stimuli and recent studies have proposed a role for NETs in viral infections. In this study, we show that RSV particles and RSV Fusion protein were both capable of inducing NET formation by human neutrophils. Moreover, we analyzed the mechanisms involved in RSV Fusion protein-induced NET formation. RSV F protein was able to induce NET release in a concentration-dependent fashion with both neutrophil elastase and myeloperoxidase expressed on DNA fibers and F protein-induced NETs was dismantled by DNase treatment, confirming that their backbone is chromatin. This viral protein caused the release of extracellular DNA dependent on TLR-4 activation, NADPH Oxidase-derived ROS production and ERK and p38 MAPK phosphorylation. Together, these results demonstrate a coordinated signaling pathway activated by F protein that led to NET production. The massive production of NETs in RSV infection could aggravate the inflammatory symptoms of the infection in young children and babies. We propose that targeting the binding of TLR-4 by F protein could potentially lead to novel therapeutic approaches to help control RSV-induced inflammatory consequences and pathology of viral bronchiolitis.

  16. Contraceptive efficacy of recombinant fusion protein comprising zona pellucida glycoprotein-3 fragment and gonadotropin releasing hormone.

    Science.gov (United States)

    Arukha, Ananta Prasad; Minhas, Vidisha; Shrestha, Abhinav; Gupta, Satish Kumar

    2016-04-01

    Contraceptive vaccines have been used for the management of wildlife population. In the present study, we have examined the contraceptive potential of Escherichia coli-expressed recombinant fusion protein comprising of 'promiscuous' T cell epitope of tetanus toxoid [TT; amino acid (aa) residues 830-844] followed by dilysine linker (KK), dog ZP3 fragment (aa residues 307-346), triglycine spacer (GGG), T cell epitope of bovine RNase (bRNase; aa residues 94-104), GnRH, T cell epitope of circumsporozoite protein of Plasmodium falciparum (CSP; aa residues 362-383), and GnRH. SDS-PAGE analysis of the purified refolded protein revealed a dominant ∼12 kDa band, which in Western blot reacted with mouse polyclonal antibodies against dog ZP3 fragment and mouse monoclonal antibodies against GnRH. Immunization of female FvB/J mice following two booster schedule with the above recombinant protein supplemented with alum led to high antibody titres against the immunogen as well as ZP3 and GnRH as determined by ELISA. The immune sera reacted with zona pellucida of mouse oocyte and also inhibited in-vitro fertilization. The qRT-PCR studies showed decrease in the ovarian GnRH receptor in mice immunized with the recombinant fusion protein. Mating studies revealed high contraceptive efficacy of the recombinant protein as in two independent experiments, 90% of the immunized female mice failed to conceive. Following one booster immunization schedule, 50% of the immunized female mice failed to conceive. However, in adjuvanted controls, all the female mice became pregnant. To conclude, the recombinant protein described herein has a good potential to be developed as candidate contraceptive vaccine. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Accumulation and processing of a recombinant protein designed as a cleavable fusion to the endogenous Rubisco LSU protein in Chlamydomonas chloroplast

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    Henry Ryan E

    2009-03-01

    Full Text Available Abstract Background Expression of recombinant proteins in green algal chloroplast holds substantial promise as a platform for the production of human therapeutic proteins. A number of proteins have been expressed in the chloroplast of Chlamydomonas reinhardtii, including complex mammalian proteins, but many of these proteins accumulate to significantly lower levels than do endogenous chloroplast proteins. We examined if recombinant protein accumulation could be enhanced by genetically fusing the recombinant reporter protein, luciferase, to the carboxy-terminal end of an abundant endogenous protein, the large subunit of ribulose bisphosphate carboxylase (Rubisco LSU. Additionally, as recombinant proteins fused to endogenous proteins are of little clinical or commercial value, we explored the possibility of engineering our recombinant protein to be cleavable from the endogenous protein in vivo. This strategy would obviate the need for further in vitro processing steps in order to produce the desired recombinant protein. To achieve this, a native protein-processing site from preferredoxin (preFd was placed between the Rubisco LSU and luciferase coding regions in the fusion protein construct. Results The luciferase from the fusion protein accumulated to significantly higher levels than luciferase expressed alone. By eliminating the endogenous Rubisco large subunit gene (rbcL, we achieved a further increase in luciferase accumulation with respect to luciferase expression in the WT background. Importantly, near-wild type levels of functional Rubisco holoenzyme were generated following the proteolytic removal of the fused luciferase, while luciferase activity for the fusion protein was almost ~33 times greater than luciferase expressed alone. These data demonstrate the utility of using fusion proteins to enhance recombinant protein accumulation in algal chloroplasts, and also show that engineered proteolytic processing sites can be used to liberate the

  18. Fusion protein-based biofilm fabrication composed of recombinant azurin–myoglobin for dual-level biomemory application

    International Nuclear Information System (INIS)

    Lee, Taek; Chung, Yong-Ho; Yoon, Jinho; Min, Junhong; Choi, Jeong-Woo

    2014-01-01

    Graphical abstract: - Highlights: • We developed the fusion protein-based biofilm on the inorganic surface. • For making the fusion protein, the recombinant azurin and the myoglobin was conjugated by the native chemical ligation method. • The developed fusion protein shows unique electrochemical property. • The proposed fusion protein biofilm appears to be a good method for dual-level biomemory device. - Abstract: In the present study, a fusion protein-based biofilm composed of a recombinant azurin–myoglobin (Azu-Myo) has been developed and confirmed its original electrochemical property for dual-level biomemory device application. For this purpose, the azurin was modified with cysteine residues for direct immobilization and conjugation. Then, the recombinant azurin was conjugated with the myoglobin via a sulfo-SMCC bifunctional linker using the chemical ligation method (CLM). The SDS-PAGE and UV–vis spectroscopy were performed to examine the fusion protein conjugates. The prepared Azu-Myo fusion protein was self-assembled onto Au substrate for the biofilm fabrication. Then, the atomic force microscopy (AFM) was used to confirm the immobilization and the surface-enhanced Raman spectroscopy (SERS) was carried out to the surface analysis. Also, the cyclic voltammetry (CV) was carried out to observe an electrochemical property of fabricated biofilm. As a result, the two pair of redox potential values was obtained for dual-level biomemory device application. Then, the dual-level biomemory function was verified by the multi-potential chronoamperometry (MPCA). The results indicate a new fabrication method and material combination for advances in bioelectronic device development

  19. NMR structure and localization of a large fragment of the SARS-CoV fusion protein: Implications in viral cell fusion.

    Science.gov (United States)

    Mahajan, Mukesh; Chatterjee, Deepak; Bhuvaneswari, Kannaian; Pillay, Shubhadra; Bhattacharjya, Surajit

    2018-02-01

    The lethal Coronaviruses (CoVs), Severe Acute Respiratory Syndrome-associated Coronavirus (SARS-CoV) and most recently Middle East Respiratory Syndrome Coronavirus, (MERS-CoV) are serious human health hazard. A successful viral infection requires fusion between virus and host cells carried out by the surface spike glycoprotein or S protein of CoV. Current models propose that the S2 subunit of S protein assembled into a hexameric helical bundle exposing hydrophobic fusogenic peptides or fusion peptides (FPs) for membrane insertion. The N-terminus of S2 subunit of SARS-CoV reported to be active in cell fusion whereby FPs have been identified. Atomic-resolution structure of FPs derived either in model membranes or in membrane mimic environment would glean insights toward viral cell fusion mechanism. Here, we have solved 3D structure, dynamics and micelle localization of a 64-residue long fusion peptide or LFP in DPC detergent micelles by NMR methods. Micelle bound structure of LFP is elucidated by the presence of discretely folded helical and intervening loops. The C-terminus region, residues F42-Y62, displays a long hydrophobic helix, whereas the N-terminus is defined by a short amphipathic helix, residues R4-Q12. The intervening residues of LFP assume stretches of loops and helical turns. The N-terminal helix is sustained by close aromatic and aliphatic sidechain packing interactions at the non-polar face. 15 N{ 1 H}NOE studies indicated dynamical motion, at ps-ns timescale, of the helices of LFP in DPC micelles. PRE NMR showed that insertion of several regions of LFP into DPC micelle core. Together, the current study provides insights toward fusion mechanism of SARS-CoV. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Production of Hev b5 as a fluorescent biotin-binding tripartite fusion protein in insect cells

    International Nuclear Information System (INIS)

    Nordlund, Henri R.; Laitinen, Olli H.; Uotila, Sanna T.H.; Kulmala, Minna; Kalkkinen, Nisse; Kulomaa, Markku S.

    2005-01-01

    The presented green fluorescent protein and streptavidin core-based tripartite fusion system provides a simple and efficient way for the production of proteins fused to it in insect cells. This fusion protein forms a unique tag, which serves as a multipurpose device enabling easy optimization of production, one-step purification via streptavidin-biotin interaction, and visualization of the fusion protein during downstream processing and in applications. In the present study, we demonstrate the successful production, purification, and detection of a natural rubber latex allergen Hev b5 with this system. We also describe the production of another NRL allergen with the system, Hev b1, which formed large aggregates and gave small yields in purification. The aggregates were detected at early steps by microscopical inspection of the infected insect cells producing this protein. Therefore, this fusion system can also be utilized as a fast indicator of the solubility of the expressed fusion proteins and may therefore be extremely useful in high-throughput expression approaches

  1. Expression and cytosolic assembly of the S-layer fusion protein mSbsC-EGFP in eukaryotic cells

    Directory of Open Access Journals (Sweden)

    Veenhuis Marten

    2005-10-01

    Full Text Available Abstract Background Native as well as recombinant bacterial cell surface layer (S-layer protein of Geobacillus (G. stearothermophilus ATCC 12980 assembles to supramolecular structures with an oblique symmetry. Upon expression in E. coli, S-layer self assembly products are formed in the cytosol. We tested the expression and assembly of a fusion protein, consisting of the mature part (aa 31–1099 of the S-layer protein and EGFP (enhanced green fluorescent protein, in eukaryotic host cells, the yeast Saccharomyces cerevisiae and human HeLa cells. Results Upon expression in E. coli the recombinant mSbsC-EGFP fusion protein was recovered from the insoluble fraction. After denaturation by Guanidine (Gua-HCl treatment and subsequent dialysis the fusion protein assembled in solution and yielded green fluorescent cylindric structures with regular symmetry comparable to that of the authentic SbsC. For expression in the eukaryotic host Saccharomyces (S. cerevisiae mSbsC-EGFP was cloned in a multi-copy expression vector bearing the strong constitutive GPD1 (glyceraldehyde-3-phosophate-dehydrogenase promoter. The respective yeast transfomants were only slightly impaired in growth and exhibited a needle-like green fluorescent pattern. Transmission electron microscopy (TEM studies revealed the presence of closely packed cylindrical structures in the cytosol with regular symmetry comparable to those obtained after in vitro recrystallization. Similar structures are observed in HeLa cells expressing mSbsC-EGFP from the Cytomegalovirus (CMV IE promoter. Conclusion The mSbsC-EGFP fusion protein is stably expressed both in the yeast, Saccharomyces cerevisiae, and in HeLa cells. Recombinant mSbsC-EGFP combines properties of both fusion partners: it assembles both in vitro and in vivo to cylindrical structures that show an intensive green fluorescence. Fusion of proteins to S-layer proteins may be a useful tool for high level expression in yeast and HeLa cells of

  2. F-18 Labeled Diabody-Luciferase Fusion Proteins for Optical-ImmunoPET

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Anna M. [Univ. of California, Los Angeles, CA (United States)

    2013-01-18

    The goal of the proposed work is to develop novel dual-labeled molecular imaging probes for multimodality imaging. Based on small, engineered antibodies called diabodies, these probes will be radioactively tagged with Fluorine-18 for PET imaging, and fused to luciferases for optical (bioluminescence) detection. Performance will be evaluated and validated using a prototype integrated optical-PET imaging system, OPET. Multimodality probes for optical-PET imaging will be based on diabodies that are dually labeled with 18F for PET detection and fused to luciferases for optical imaging. 1) Two sets of fusion proteins will be built, targeting the cell surface markers CEA or HER2. Coelenterazine-based luciferases and variant forms will be evaluated in combination with native substrate and analogs, in order to obtain two distinct probes recognizing different targets with different spectral signatures. 2) Diabody-luciferase fusion proteins will be labeled with 18F using amine reactive [18F]-SFB produced using a novel microwave-assisted, one-pot method. 3) Sitespecific, chemoselective radiolabeling methods will be devised, to reduce the chance that radiolabeling will inactivate either the target-binding properties or the bioluminescence properties of the diabody-luciferase fusion proteins. 4) Combined optical and PET imaging of these dual modality probes will be evaluated and validated in vitro and in vivo using a prototype integrated optical-PET imaging system, OPET. Each imaging modality has its strengths and weaknesses. Development and use of dual modality probes allows optical imaging to benefit from the localization and quantitation offered by the PET mode, and enhances the PET imaging by enabling simultaneous detection of more than one probe.

  3. Delayed Toxicity Associated with Soluble Anthrax Toxin Receptor Decoy-Ig Fusion Protein Treatment

    Science.gov (United States)

    Cote, Christopher; Welkos, Susan; Manchester, Marianne; Young, John A. T.

    2012-01-01

    Soluble receptor decoy inhibitors, including receptor-immunogloubulin (Ig) fusion proteins, have shown promise as candidate anthrax toxin therapeutics. These agents act by binding to the receptor-interaction site on the protective antigen (PA) toxin subunit, thereby blocking toxin binding to cell surface receptors. Here we have made the surprising observation that co-administration of receptor decoy-Ig fusion proteins significantly delayed, but did not protect, rats challenged with anthrax lethal toxin. The delayed toxicity was associated with the in vivo assembly of a long-lived complex comprised of anthrax lethal toxin and the receptor decoy-Ig inhibitor. Intoxication in this system presumably results from the slow dissociation of the toxin complex from the inhibitor following their prolonged circulation. We conclude that while receptor decoy-Ig proteins represent promising candidates for the early treatment of B. anthracis infection, they may not be suitable for therapeutic use at later stages when fatal levels of toxin have already accumulated in the bloodstream. PMID:22511955

  4. Prediction of protein folds: extraction of new features, dimensionality reduction, and fusion of heterogeneous classifiers.

    Science.gov (United States)

    Ghanty, Pradip; Pal, Nikhil R

    2009-03-01

    Here, we consider a two-level (four classes in level 1 and 27 folds in level 2) protein fold determination problem. We propose several new features and use some existing features including frequencies of adjacent residues, frequencies of residues separated by one residue, and triplets (trio) of amino acid compositions (AACs). The dimensionality of the trio AAC features is drastically reduced using a neural network based novel online feature selection scheme. We also propose new sets of features called trio potential computed using the hydrophobicity values considering only the selected trio AACs. We demonstrate that the proposed features including the selected trio AACs and trio potential have good discriminating power for protein fold determination. As machine learning tools, we use multilayer perceptron network, radial basis function network, and support vector machine. To improve the recognition accuracies further, we use fusion of different classifiers using the same set of features as well as different sets of features. The effectiveness of our schemes is demonstrated with a benchmark structural classification of proteins (SCOP) dataset. Our system achieves 84.9% test accuracy for the SCOP structural class (four classes) determination and 68.6% test accuracy for the fold recognition with 27 folds. In order to demonstrate the consistency of feature sets and fusion schemes, we also perform the fivefold cross-validation experiments.

  5. Cytoplasmic Motifs in the Nipah Virus Fusion Protein Modulate Virus Particle Assembly and Egress.

    Science.gov (United States)

    Johnston, Gunner P; Contreras, Erik M; Dabundo, Jeffrey; Henderson, Bryce A; Matz, Keesha M; Ortega, Victoria; Ramirez, Alfredo; Park, Arnold; Aguilar, Hector C

    2017-05-15

    Nipah virus (NiV), a paramyxovirus in the genus Henipavirus , has a mortality rate in humans of approximately 75%. While several studies have begun our understanding of NiV particle formation, the mechanism of this process remains to be fully elucidated. For many paramyxoviruses, M proteins drive viral assembly and egress; however, some paramyxoviral glycoproteins have been reported as important or essential in budding. For NiV the matrix protein (M), the fusion glycoprotein (F) and, to a much lesser extent, the attachment glycoprotein (G) autonomously induce the formation of virus-like particles (VLPs). However, functional interactions between these proteins during assembly and egress remain to be fully understood. Moreover, if the F-driven formation of VLPs occurs through interactions with host cell machinery, the cytoplasmic tail (CT) of F is a likely interactive domain. Therefore, we analyzed NiV F CT deletion and alanine mutants and report that several but not all regions of the F CT are necessary for efficient VLP formation. Two of these regions contain YXXØ or dityrosine motifs previously shown to interact with cellular machinery involved in F endocytosis and transport. Importantly, our results showed that F-driven, M-driven, and M/F-driven viral particle formation enhanced the recruitment of G into VLPs. By identifying key motifs, specific residues, and functional viral protein interactions important for VLP formation, we improve our understanding of the viral assembly/egress process and point to potential interactions with host cell machinery. IMPORTANCE Henipaviruses can cause deadly infections of medical, veterinary, and agricultural importance. With recent discoveries of new henipa-like viruses, understanding the mechanisms by which these viruses reproduce is paramount. We have focused this study on identifying the functional interactions of three Nipah virus proteins during viral assembly and particularly on the role of one of these proteins, the

  6. Evaluation of a novel methacrylate-based Protein A resin for the purification of immunoglobulins and Fc-fusion proteins.

    Science.gov (United States)

    McCaw, Tyler R; Koepf, Edward K; Conley, Lynn

    2014-01-01

    Protein A affinity chromatography is a central part of most commercial monoclonal antibody and Fc-fusion protein purification processes. In the last couple years an increasing number of new Protein A technologies have emerged. One of these new Protein A technologies consists of a novel, alkaline-tolerant, Protein A ligand coupled to a macroporous polymethacrylate base matrix that has been optimized for immunoglobulin (Ig) G capture. The resin is interesting from a technology perspective because the particle size and pore distribution of the base beads are reported to have been optimized for high IgG binding and fast mass transfer, while the Protein A ligand has been engineered for enhanced alkaline tolerance. This resin was subjected to a number of technical studies including evaluating dynamic and static binding capacities, alkaline stability, Protein A leachate propensity, impurity clearance, and pressure-flow behavior. The results demonstrated similar static binding capacities as those achieved with industry standard agarose Protein A resins, but marginally lower dynamic binding capacities. Removal of impurities from the process stream, particularly host cell proteins, was molecule dependent, but in most instances matched the performance of the agarose resins. This resin was stable in 0.1 M NaOH for at least 100 h with little loss in binding capacity, with Protein A ligand leakage levels comparable to values for the agarose resins. Pressure-flow experiments in lab-scale chromatography columns demonstrated minimal resin compression at typical manufacturing flow rates. Prediction of resin compression in manufacturing scale columns did not suggest any pressure limitations upon scale up. © 2014 American Institute of Chemical Engineers.

  7. Human cytomegaloviruses expressing yellow fluorescent fusion proteins--characterization and use in antiviral screening.

    Directory of Open Access Journals (Sweden)

    Sarah Straschewski

    Full Text Available Recombinant viruses labelled with fluorescent proteins are useful tools in molecular virology with multiple applications (e.g., studies on intracellular trafficking, protein localization, or gene activity. We generated by homologous recombination three recombinant cytomegaloviruses carrying the enhanced yellow fluorescent protein (EYFP fused with the viral proteins IE-2, ppUL32 (pp150, and ppUL83 (pp65. In growth kinetics, the three viruses behaved all like wild type, even at low multiplicity of infection (MOI. The expression of all three fusion proteins was detected, and their respective localizations were the same as for the unmodified proteins in wild-type virus-infected cells. We established the in vivo measurement of fluorescence intensity and used the recombinant viruses to measure inhibition of viral replication by neutralizing antibodies or antiviral substances. The use of these viruses in a pilot screen based on fluorescence intensity and high-content analysis identified cellular kinase inhibitors that block viral replication. In summary, these viruses with individually EYFP-tagged proteins will be useful to study antiviral substances and the dynamics of viral infection in cell culture.

  8. NUP98-Fusion Proteins Interact With the NSL and MLL1 Complexes To Drive Leukemogenesis

    OpenAIRE

    Xu, Haiming; Valerio, Daria G; Eisold, Meghan E; Sinha, Amit; Koche, Richard P; Hu, Wenhuo; Chen, Chun-Wei; Chu, S Haihua; Brien, Gerard L; Park, Christopher Y.; Hsieh, James J.; Ernst, Patricia; Armstrong, Scott A

    2016-01-01

    The Nucleoporin 98 gene (NUP98) is fused to a variety of partner genes in multiple hematopoietic malignancies. Here we demonstrate that NUP98 fusion proteins, including NUP98-HOXA9 (NHA9), NUP98-HOXD13 (NHD13), NUP98-NSD1, NUP98-PHF23, and NUP98-TOP1 physically interact with mixed lineage leukemia 1 (MLL1) and the non-specific lethal (NSL) histone-modifying complexes. ChIP-seq illustrates that NHA9 and MLL1 co-localize on chromatin and are found associated with Hox gene promoter regions. Furt...

  9. A Maltose-Binding Protein Fusion Construct Yields a Robust Crystallography Platform for MCL1.

    Directory of Open Access Journals (Sweden)

    Matthew C Clifton

    Full Text Available Crystallization of a maltose-binding protein MCL1 fusion has yielded a robust crystallography platform that generated the first apo MCL1 crystal structure, as well as five ligand-bound structures. The ability to obtain fragment-bound structures advances structure-based drug design efforts that, despite considerable effort, had previously been intractable by crystallography. In the ligand-independent crystal form we identify inhibitor binding modes not observed in earlier crystallographic systems. This MBP-MCL1 construct dramatically improves the structural understanding of well-validated MCL1 ligands, and will likely catalyze the structure-based optimization of high affinity MCL1 inhibitors.

  10. A mature and fusogenic form of the Nipah virus fusion protein requires proteolytic processing by cathepsin L

    International Nuclear Information System (INIS)

    Pager, Cara Theresia; Craft, Willie Warren; Patch, Jared; Dutch, Rebecca Ellis

    2006-01-01

    The Nipah virus fusion (F) protein is proteolytically processed to F 1 + F 2 subunits. We demonstrate here that cathepsin L is involved in this important maturation event. Cathepsin inhibitors ablated cleavage of Nipah F. Proteolytic processing of Nipah F and fusion activity was dramatically reduced in cathepsin L shRNA-expressing Vero cells. Additionally, Nipah virus F-mediated fusion was inhibited in cathepsin L-deficient cells, but coexpression of cathepsin L restored fusion activity. Both purified cathepsin L and B could cleave immunopurified Nipah F protein, but only cathepsin L produced products of the correct size. Our results suggest that endosomal cathepsins can cleave Nipah F, but that cathepsin L specifically converts Nipah F to a mature and fusogenic form

  11. Subcellular Localization and Calcium and pH Requirements for Proteolytic Processing of the Hendra Virus Fusion Protein

    OpenAIRE

    Pager, Cara Theresia; Wurth, Mark Allen; Dutch, Rebecca Ellis

    2004-01-01

    Proteolytic cleavage of the Hendra virus fusion (F) protein results in the formation of disulfide-linked F1 and F2 subunits, with cleavage occurring after residue K109 in the sequence GDVK↓L. This unusual cleavage site and efficient propagation of Hendra virus in a furin-deficient cell line indicate that the Hendra F protein is not cleaved by furin, the protease responsible for proteolytic activation of many viral fusion proteins. To identify the subcellular site of Hendra F processing, Vero ...

  12. The small G-proteins Rac1 and Cdc42 are essential for myoblast fusion in the mouse

    DEFF Research Database (Denmark)

    Vasyutina, Elena; Martarelli, Benedetta; Brakebusch, Cord

    2009-01-01

    Rac1 and Cdc42 are small G-proteins that regulate actin dynamics and affect plasma membrane protrusion and vesicle traffic. We used conditional mutagenesis in mice to demonstrate that Rac1 and Cdc42 are essential for myoblast fusion in vivo and in vitro. The deficit in fusion of Rac1 or Cdc42...... mutant myoblasts correlates with a deficit in the recruitment of actin fibers and vinculin to myoblast contact sites. Comparison of the changes observed in mutant myogenic cells indicates that Rac1 and Cdc42 function in a nonredundant and not completely overlapping manner during the fusion process. Our...

  13. The study of the intercellular trafficking of the fusion proteins of herpes simplex virus protein VP22.

    Science.gov (United States)

    Xue, Xiaodong; Huang, Jianhua; Wang, Huishan

    2014-01-01

    Genetic modifications can improve the therapeutic efficacy of mesenchymal stem cell (MSC) transplantation in myocardial infarction. However, so far, the efficiency of MSC modification is very low. Seeking for a more efficient way of MSC modification, we investigated the possibility of employing the intercellular trafficking capacity of the herpes simplex virus type-1 tegument protein VP22 on the enhancement of MSC modification. Plasmids pVP22-myc, pVP22-EGFP, pEGFP-VP22, pVP22-hBcl-xL and phBcl-xL-VP22 were constructed for the expressions of the myc-tagged VP22 and the fusion proteins VP22-EGFP, EGFP-VP22, VP22-hBcl-xL and hBcl-xL-VP22. MSCs were isolated from rat bone marrow and the surface markers were identified by Flowcytometry. COS-1 cells were transfected with the above plasmids and co-cultured with untransfected MSCs, the intercellular transportations of the constructed proteins were studied by immunofluorescence. The solubility of VP22-hBcl-xL and hBcl-xL-VP22 was analyzed by Western blot. VP22-myc could be expressed in and spread between COS-1 cells, which indicates the validity of our VP22 expression construct. Flowcytometry analysis revealed that the isolated MSCs were CD29, CD44, and CD90 positive and were negative for the hematopoietic markers, CD34 and CD45. The co-culturing and immunofluorescence assay showed that VP22-myc, VP22-EGFP and EGFP-VP22 could traffic between COS-1 cells and MSCs, while the evidence of intercellular transportation of VP22-hBcl-xL and hBcl-xL-VP22 was not detected. Western blot analysis showed that VP22-hBcl-xL and hBcl-xL-VP22 were both insoluble in the cell lysate suggesting interactions of the fusion proteins with other cellular components. The intercellular trafficking of VP22-myc, VP22-EGFP and EGFP-VP22 between COS-1 cells and MSCs presents an intriguing prospect in the therapeutic application of VP22 as a delivery vehicle which enhances genetic modifications of MSCs. However, VP22-hBcl-xL and hBcl-xL-VP22 failed to

  14. Fusion proteins and select lipids cooperate as membrane receptors for the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) Vam7p.

    Science.gov (United States)

    Karunakaran, Vidya; Wickner, William

    2013-10-04

    Vam7p, the vacuolar soluble Qc-SNARE, is essential for yeast vacuole fusion. The large tethering complex, homotypic fusion and vacuole protein sorting complex (HOPS), and phosphoinositides, which interact with the Vam7p PX domain, have each been proposed to serve as its membrane receptors. Studies with the isolated organelle cannot determine whether these receptor elements suffice and whether ligands or mutations act directly or indirectly on Vam7p binding to the membrane. Using pure components that are active in reconstituted vacuolar fusion, we now find that Vam7p binds to membranes through its combined affinities for several vacuolar membrane constituents: HOPS, phosphatidylinositol 3-phosphate, SNAREs, and acidic phospholipids. Acidic lipids allow low concentrations of Vam7p to suffice for fusion; without acidic lipids, the block to fusion is partially bypassed by high concentrations of Vam7p.

  15. Mistic and TarCF as fusion protein partners for functional expression of the cannabinoid receptor 2 in Escherichia coli.

    Science.gov (United States)

    Chowdhury, Ananda; Feng, Rentian; Tong, Qin; Zhang, Yuxun; Xie, Xiang-Qun

    2012-06-01

    G protein coupled receptors (GPCRs) are key players in signal recognition and cellular communication making them important therapeutic targets. Large-scale production of these membrane proteins in their native form is crucial for understanding their mechanism of action and target-based drug design. Here we report the overexpression system for a GPCR, the cannabinoid receptor subtype 2 (CB2), in Escherichia coli C43(DE3) facilitated by two fusion partners: Mistic, an integral membrane protein expression enhancer at the N-terminal, and TarCF, a C-terminal fragment of the bacterial chemosensory transducer Tar at the C-terminal of the CB2 open reading frame region. Multiple histidine tags were added on both ends of the fusion protein to facilitate purification. Using individual and combined fusion partners, we found that CB2 fusion protein expression was maximized only when both partners were used. Variable growth and induction conditions were conducted to determine and optimize protein expression. More importantly, this fusion protein Mistic-CB2-TarCF can localize into the E. coli membrane and exhibit functional binding activities with known CB2 ligands including CP55,940, WIN55,212-2 and SR144,528. These results indicate that this novel expression and purification system provides us with a promising strategy for the preparation of biologically active GPCRs, as well as general application for the preparation of membrane-bound proteins using the two new fusion partners described. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Fluorescence fluctuation analysis of BACE1-GFP fusion protein in cultured HEK293 cells

    Science.gov (United States)

    Gardeen, Spencer; Johnson, Joseph L.; Heikal, Ahmed A.

    2016-10-01

    Beta-site APP cleaving enzyme 1 (BACE1) is a type I transmembrane aspartyl protease. In the amyloidogenic pathway, BACE1 provides β-secretase activity that cleaves the amyloid precursor protein (APP) that leads to amyloid beta (Aβ) peptides. The aggregation of these Aβ will ultimately results in amyloid plaque formation, a hallmark of Alzheimer's disease (AD). Amyloid aggregation leads to progressive memory impairment and neural loss. Recent detergent protein extraction studies suggest that the untreated BACE1 protein forms a dimer that has significantly higher catalytic activity than its monomeric counterpart. Here, we examine the dimerization hypothesis of BACE1 in cultured HEK293 cells using fluorescence correlation spectroscopy (FCS). Cells were transfected with a BACE1-EGFP fusion protein construct and imaged using confocal and DIC microscopy to monitor labeled BACE1 localization and distribution within the cell. Our one-photon fluorescence fluctuation autocorrelation of BACE1- EGFP on the plasma membrane of HEK cells is modeled using two diffusing species on the plasma membrane with estimated diffusion coefficients of 1.39 x 10-7 cm2/sec and 2.8 x 10-8 cm2/sec under resting conditions and STA-200 inhibition, respectively. Anomalous diffusion model also provided adequate description of the observed autocorrelation function of BACE1- EGFP on the plasma membrane with an estimate exponent (α) of 0.8 and 0.5 for resting and STA-200 treated cells, respectively. The corresponding hydrodynamic radius of this transmembrane fusion protein was estimated using the measured diffusion coefficients assuming both Stokes-Einstein and Saffman-Delbruck models. Our results suggest a complex diffusion pattern of BACE1-EGFP on the plasma membrane of HEK cells with the possibility for dimer formation, especially under STA-200 inhibition.

  17. Fusion protein strategy to increase expression and solubility of hypervariable region of VP2 protein of infectious bursal disease virus in Escherichia coli.

    Science.gov (United States)

    Sedighzadeh, Sahar Sadat; Shamsara, Mehdi; Shahpiri, Azar

    2012-10-01

    Infectious bursal disease is one of the most important viral diseases in the young chickens. VP2 protein is the major host protective immunogen of the virus. A hypervariable region is present in VP2 protein (hvVP2) that contains immunodominant epitops. The high hydrophobicity of hvVP2 region causes protein aggregation in Escherichia coli (E. coli). The objective of the present study was to improve the expression and the solubility of the hvVP2 protein in E. coli. The effects of fusion partners on the solubility of hvVP2 protein were studied. The protein was expressed in forms of unfused and N-terminally fused to GST and NusA. The results showed that the unfused hvVP2 protein was expressed in very low level. But, N-terminally fused hvVP2 protein to GST (glutathione-S-transferase) and NusA (N utilization substance A) showed significantly enhanced protein expression. The fusion of GST and hvVP2 was produced in aggregated form while in the presence of NusA, the hvVP2 protein was expressed in a soluble form. The NusA-hvVP2 protein was detected by a neutralizing monoclonal antibody, 1A6, in antigen-capture ELISA. In conclusion, the NusA protein is a suitable fusion partner to improve expression and solubility of the hvVP2 protein in E. coli.

  18. Structural and kinetic analysis of the unnatural fusion protein 4-coumaroyl-CoA ligase::stilbene synthase

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yechun; Yi, Hankuil; Wang, Melissa; Yu, Oliver; Jez, Joseph M. (WU); (Danforth)

    2012-10-24

    To increase the biochemical efficiency of biosynthetic systems, metabolic engineers have explored different approaches for organizing enzymes, including the generation of unnatural fusion proteins. Previous work aimed at improving the biosynthesis of resveratrol, a stilbene associated a range of health-promoting activities, in yeast used an unnatural engineered fusion protein of Arabidopsis thaliana (thale cress) 4-coumaroyl-CoA ligase (At4CL1) and Vitis vinifera (grape) stilbene synthase (VvSTS) to increase resveratrol levels 15-fold relative to yeast expressing the individual enzymes. Here we present the crystallographic and biochemical analysis of the 4CL::STS fusion protein. Determination of the X-ray crystal structure of 4CL::STS provides the first molecular view of an artificial didomain adenylation/ketosynthase fusion protein. Comparison of the steady-state kinetic properties of At4CL1, VvSTS, and 4CL::STS demonstrates that the fusion protein improves catalytic efficiency of either reaction less than 3-fold. Structural and kinetic analysis suggests that colocalization of the two enzyme active sites within 70 {angstrom} of each other provides the basis for enhanced in vivo synthesis of resveratrol.

  19. ROS1 protein-tyrosine kinase inhibitors in the treatment of ROS1 fusion protein-driven non-small cell lung cancers.

    Science.gov (United States)

    Roskoski, Robert

    2017-07-01

    ROS1 protein-tyrosine kinase fusion proteins are expressed in 1-2% of non-small cell lung cancers. The ROS1 fusion partners include CD74, CCDC6, EZR, FIG, KDELR2, LRIG3, MSN, SDC4, SLC34A2, TMEM106B, TMP3, and TPD52L1. Physiological ROS1 is closely related to the ALK, LTK, and insulin receptor protein-tyrosine kinases. ROS1 is a so-called orphan receptor because the identity of its activating ligand, if any, is unknown. The receptor is expressed during development, but little is expressed in adults and its physiological function is unknown. The human ROS1 gene encodes 2347 amino acid residues and ROS1 is the largest protein-tyrosine kinase receptor protein. Unlike the ALK fusion proteins that are activated by the dimerization induced by their amino-terminal portions, the amino-terminal domains of several of its fusion proteins including CD74 apparently lack the ability to induce dimerization so that the mechanism of constitutive protein kinase activation is unknown. Downstream signaling from the ROS1 fusion protein leads to the activation of the Ras/Raf/MEK/ERK1/2 cell proliferation module, the phosphatidyl inositol 3-kinase cell survival pathway, and the Vav3 cell migration pathway. Moreover, several of the ROS1 fusion proteins are implicated in the pathogenesis of a very small proportion of other cancers including glioblastoma, angiosarcoma, and cholangiocarcinoma as well as ovarian, gastric, and colorectal carcinomas. The occurrence of oncogenic ROS1 fusion proteins, particularly in non-small cell lung cancer, has fostered considerable interest in the development of ROS1 inhibitors. Although the percentage of lung cancers driven by ROS1 fusion proteins is low, owing to the large number of new cases of non-small cell lung cancer per year, the number of new cases of ROS1-positive lung cancers is significant and ranges from 2000 to 4000 per year in the United States and 10,000-15,000 worldwide. Crizotinib was the first inhibitor approved by the US Food and Drug

  20. Semliki Forest virus produced in the absence of the 6K protein has an altered spike structure as revealed by decreased membrane fusion capacity

    NARCIS (Netherlands)

    McInerney, GM; Smit, JM; Liljestrom, P; Wilschut, J

    2004-01-01

    We examined the kinetics of membrane fusion of wild type (wt) and Delta6K mutant Semliki Forest virus in a liposomal model system. The final extent of membrane fusion of the mutant (at pH 5.5) was approximately one third that of the wt virus, although the level of E1 (fusion protein) trimerization

  1. Functional analysis of the NUP98-CCDC28A fusion protein.

    Science.gov (United States)

    Petit, Arnaud; Ragu, Christine; Soler, Gwendoline; Ottolenghi, Chris; Schluth, Caroline; Radford-Weiss, Isabelle; Schneider-Maunoury, Sylvie; Callebaut, Isabelle; Dastugue, Nicole; Drabkin, Harry A; Bernard, Olivier A; Romana, Serge; Penard-Lacronique, Virginie

    2012-03-01

    The nucleoporin gene NUP98 is rearranged in more than 27 chromosomal abnormalities observed in childhood and adult, de novo and therapy-related acute leukemias of myeloid and T-lymphoid origins, resulting in the creation of fusion genes and the expression of chimeric proteins. We report here the functional analysis of the NUP98-coiled-coil domain-containing protein 28A (NUP98-CCDC28A) fusion protein, expressed as the consequence of a recurrent t(6;11)(q24.1;p15.5) translocation. To gain insight into the function of the native CCDC28A gene, we collected information on any differential expression of CCDC28A among normal hematologic cell types and within subgroups of acute leukemia. To assess the in vivo effects of the NUP98-CCDC28A fusion, NUP98-CCDC28A or full length CCDC28A were retrovirally transduced into primary murine bone marrow cells and transduced cells were next transplanted into sub-lethally irradiated recipient mice. Our in silico analyses supported a contribution of CCDC28A to discrete stages of murine hematopoietic development. They also suggested selective enrichment of CCDC28A in the French-American-British M6 class of human acute leukemia. Primary murine hematopoietic progenitor cells transduced with NUP98-CCDC28A generated a fully penetrant and transplantable myeloproliferative neoplasm-like myeloid leukemia and induced selective expansion of granulocyte/macrophage progenitors in the bone marrow of transplanted recipients, showing that NUP98-CCDC28A promotes the proliferative capacity and self-renewal potential of myeloid progenitors. In addition, the transformation mediated by NUP98-CCDC28A was not associated with deregulation of the Hoxa-Meis1 pathway, a feature shared by a diverse set of NUP98 fusions. Our results demonstrate that the recurrent NUP98-CCDC28A is an oncogene that induces a rapid and transplantable myeloid neoplasm in recipient mice. They also provide additional evidence for an alternative leukemogenic mechanism for NUP98 oncogenes.

  2. Human antibody recognition of antigenic site IV on Pneumovirus fusion proteins.

    Science.gov (United States)

    Mousa, Jarrod J; Binshtein, Elad; Human, Stacey; Fong, Rachel H; Alvarado, Gabriela; Doranz, Benjamin J; Moore, Martin L; Ohi, Melanie D; Crowe, James E

    2018-02-01

    Respiratory syncytial virus (RSV) is a major human pathogen that infects the majority of children by two years of age. The RSV fusion (F) protein is a primary target of human antibodies, and it has several antigenic regions capable of inducing neutralizing antibodies. Antigenic site IV is preserved in both the pre-fusion and post-fusion conformations of RSV F. Antibodies to antigenic site IV have been described that bind and neutralize both RSV and human metapneumovirus (hMPV). To explore the diversity of binding modes at antigenic site IV, we generated a panel of four new human monoclonal antibodies (mAbs) and competition-binding suggested the mAbs bind at antigenic site IV. Mutagenesis experiments revealed that binding and neutralization of two mAbs (3M3 and 6F18) depended on arginine (R) residue R429. We discovered two R429-independent mAbs (17E10 and 2N6) at this site that neutralized an RSV R429A mutant strain, and one of these mAbs (17E10) neutralized both RSV and hMPV. To determine the mechanism of cross-reactivity, we performed competition-binding, recombinant protein mutagenesis, peptide binding, and electron microscopy experiments. It was determined that the human cross-reactive mAb 17E10 binds to RSV F with a binding pose similar to 101F, which may be indicative of cross-reactivity with hMPV F. The data presented provide new concepts in RSV immune recognition and vaccine design, as we describe the novel idea that binding pose may influence mAb cross-reactivity between RSV and hMPV. Characterization of the site IV epitope bound by human antibodies may inform the design of a pan-Pneumovirus vaccine.

  3. The pharmacological efficacy of the anti-IL17 scFv and sTNFR1 bispecific fusion protein in inflammation mouse stimulated by LPS.

    Science.gov (United States)

    Yang, Yongbi; Zhang, Teng; Cao, Hongxue; Yu, Dan; Zhang, Tong; Zhao, Shaojuan; Jing, Xiaohui; Song, Liying; Liu, Yunye; Che, Ruixiang; Liu, Xin; Li, Deshan; Ren, Guiping

    2017-08-01

    Acute lung injury (ALI) is still a leading cause of morbidity and mortality in critically ill patients. Recently, our study found that a bispecific fusion protein treatment can ameliorate the lung injury induced by LPS. However, the molecular mechanisms which bispecific fusion protein ameliorates acute lung injury remain unclear. In this study, we found that the bispecific fusion protein treatment inhibited the nuclear transcription of NF-κB in confocal laser scanning fluorescence microscopy, the bispecific fusion protein exert protective effects in the cell model of ALI induced by lipopolysaccharide (LPS) via inhibiting the nuclear factor κB (NF-κB) signaling pathway and mediate inflammation. Moreover, the treatment of the bispecific fusion protein show its efficacy in animal models stimulated by LPS, the results of real-time PCR and ELISA demonstrate that bispecific fusion protein treatment effectively inhibited the over-expression of inflammatory cytokines(tumor necrosis factor α, interleukin 1β and interleukin 17). In addition, LPS-challenged mice exhibited significant lung injury characterized by the deterioration of histopathology, which was meliorated by bispecific fusion protein treatment. Collectively, these results demonstrate that bispecific fusion protein treatment ameliorates LPS-induced ALI through reducing inflammatory cytokines and lung inflammation, which may be associated with the decreased the nuclear transcription of NF-κB. The bispecific fusion protein may be useful as a novel therapy to treat ALI. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. Fusion and subsidence rate of stand alone anterior lumbar interbody fusion using PEEK cage with recombinant human bone morphogenetic protein-2.

    Science.gov (United States)

    Behrbalk, Eyal; Uri, Ofir; Parks, Ruth M; Musson, Rachel; Soh, Reuben Chee Cheong; Boszczyk, Bronek Maximilian

    2013-12-01

    Anterior lumbar interbody fusion (ALIF) is an established treatment for structural instability associated with symptomatic disk degeneration (SDD). Stand-alone ALIF offers many advantages, however, it may increase the risk of non-union. Recombinant human bone morphogenetic protein-2 (BMP-2) may enhance fusion rate but is associated with postoperative complication. The optimal dose of BMP-2 remains unclear. This study assessed the fusion and subsidence rates of stand-alone ALIF using the SynFix-LR interbody cage with 6 ml/level of BMP-2. Thirty-two ALIF procedures were performed by a single surgeon in 25 patients. Twenty-five procedures were performed for SDD without spondylolisthesis (SDD group) and seven procedures were performed for SDD with grade-I olisthesis (SDD-olisthesis group). Patients were followed-up for a mean of 17 ± 6 months. Solid fusion was achieved in 29 cases (90.6 %) within 6 months postoperatively. Five cases of implant subsidence were observed (16 %). Four of these occurred in the SDD-olisthesis group and one occurred in the SDD group (57 % vs. 4 % respectively; p = 0.004). Three cases of subsidence failed to fuse and required revision. The body mass index of patients with olisthesis who developed subsidence was higher than those who did not develop subsidence (29 ± 2.6 vs. 22 ± 6.5 respectively; p = 0.04). No BMP-2 related complications occurred. The overall fusion rate of stand-alone ALIF using the SynFix-LR system with BMP-2 was 90.6 %, comparable with other published series. No BMP-2 related complication occurred at a dose of 6 mg/level. Degenerative spondylolisthesis and obesity seemed to increase the rate of implant subsidence, and thus we believe that adding posterior fusion for these cases should be considered.

  5. Expression, Purification, and Biophysical Characterization of a Secreted Anthrax Decoy Fusion Protein in Nicotiana benthamiana

    Directory of Open Access Journals (Sweden)

    Kalimuthu Karuppanan

    2017-01-01

    Full Text Available Anthrax toxin receptor-mediated drug development for blocking anthrax toxin action has received much attention in recent decades. In this study, we produced a secreted anthrax decoy fusion protein comprised of a portion of the human capillary morphogenesis gene-2 (CMG2 protein fused via a linker to the fragment crystallizable (Fc domain of human immunoglobulin G1 in Nicotiana benthamiana plants using a transient expression system. Using the Cauliflower Mosaic Virus (CaMV 35S promoter and co-expression with the p19 gene silencing suppressor, we were able to achieve a high level of recombinant CMG2-Fc-Apo (rCMG2-Fc-Apo protein accumulation. Production kinetics were observed up to eight days post-infiltration, and maximum production of 826 mg/kg fresh leaf weight was observed on day six. Protein A affinity chromatography purification of the rCMG2-Fc-Apo protein from whole leaf extract and apoplast wash fluid showed the homodimeric form under non-reducing gel electrophoresis and mass spectrometry analysis confirmed the molecular integrity of the secreted protein. The N-glycosylation pattern of purified rCMG2-Fc-Apo protein was analysed; the major portion of N-glycans consists of complex type structures in both protein samples. The most abundant (>50% N-glycan structure was GlcNAc2(XylMan3(FucGlcNAc2 in rCMG2-Fc-Apo recovered from whole leaf extract and apoplast wash fluid. High mannose N-glycan structures were not detected in the apoplast wash fluid preparation, which confirmed the protein secretion. Altogether, these findings demonstrate that high-level production of rCMG2-Fc-Apo can be achieved by transient production in Nicotiana benthamiana plants with apoplast targeting.

  6. Recombinant GDNF: Tetanus toxin fragment C fusion protein produced from insect cells

    International Nuclear Information System (INIS)

    Li, Jianhong; Chian, Ru-Ju; Ay, Ilknur; Celia, Samuel A.; Kashi, Brenda B.; Tamrazian, Eric; Matthews, Jonathan C.; Remington, Mary P.; Pepinsky, R. Blake; Fishman, Paul S.; Brown, Robert H.; Francis, Jonathan W.

    2009-01-01

    Glial cell line-derived neurotrophic factor (GDNF) has potent survival-promoting effects on CNS motor neurons in experimental animals. Its therapeutic efficacy in humans, however, may have been limited by poor bioavailability to the brain and spinal cord. With a view toward improving delivery of GDNF to CNS motor neurons in vivo, we generated a recombinant fusion protein comprised of rat GDNF linked to the non-toxic, neuron-binding fragment of tetanus toxin. Recombinant GDNF:TTC produced from insect cells was a soluble homodimer like wild-type GDNF and was bi-functional with respect to GDNF and TTC activity. Like recombinant rat GDNF, the fusion protein increased levels of immunoreactive phosphoAkt in treated NB41A3-hGFRα-1 neuroblastoma cells. Like TTC, GDNF:TTC bound to immobilized ganglioside GT1b in vitro with high affinity and selectivity. These results support further testing of recombinant GDNF:TTC as a non-viral vector to improve delivery of GDNF to brain and spinal cord in vivo.

  7. Recombinant GDNF: Tetanus toxin fragment C fusion protein produced from insect cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianhong; Chian, Ru-Ju; Ay, Ilknur; Celia, Samuel A.; Kashi, Brenda B.; Tamrazian, Eric; Matthews, Jonathan C. [Cecil B. Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129 (United States); Remington, Mary P. [Research Service, Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201 (United States); Pepinsky, R. Blake [BiogenIdec, Inc., 14 Cambridge Center, Cambridge, MA 02142 (United States); Fishman, Paul S. [Research Service, Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201 (United States); Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201 (United States); Brown, Robert H. [Cecil B. Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129 (United States); Francis, Jonathan W., E-mail: jwfrancisby@gmail.com [Cecil B. Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129 (United States)

    2009-07-31

    Glial cell line-derived neurotrophic factor (GDNF) has potent survival-promoting effects on CNS motor neurons in experimental animals. Its therapeutic efficacy in humans, however, may have been limited by poor bioavailability to the brain and spinal cord. With a view toward improving delivery of GDNF to CNS motor neurons in vivo, we generated a recombinant fusion protein comprised of rat GDNF linked to the non-toxic, neuron-binding fragment of tetanus toxin. Recombinant GDNF:TTC produced from insect cells was a soluble homodimer like wild-type GDNF and was bi-functional with respect to GDNF and TTC activity. Like recombinant rat GDNF, the fusion protein increased levels of immunoreactive phosphoAkt in treated NB41A3-hGFR{alpha}-1 neuroblastoma cells. Like TTC, GDNF:TTC bound to immobilized ganglioside GT1b in vitro with high affinity and selectivity. These results support further testing of recombinant GDNF:TTC as a non-viral vector to improve delivery of GDNF to brain and spinal cord in vivo.

  8. A High Performance Platform Based on cDNA Display for Efficient Synthesis of Protein Fusions and Accelerated Directed Evolution.

    Science.gov (United States)

    Naimuddin, Mohammed; Kubo, Tai

    2016-02-08

    We describe a high performance platform based on cDNA display technology by developing a new modified puromycin linker-oligonucleotide. The linker consists of four major characteristics: a "ligation site" for hybridization and ligation of mRNA by T4 RNA ligase, a "puromycin arm" for covalent linkage of the protein, a "polyadenosine site" for a longer puromycin arm and purification of protein fusions (optional) using oligo-dT matrices, and a "reverse transcription site" for the formation of stable cDNA protein fusions whose cDNA is covalently linked to its encoded protein. The linker was synthesized by a novel branching strategy and provided >8-fold higher yield than previous linkers. This linker enables rapid and highly efficient ligation of mRNA (>90%) and synthesis of protein fusions (∼ 50-95%) in various cell-free expression systems. Overall, this new cDNA display method provides 10-200 fold higher end-usage fusions than previous methods and benefits higher diversity libraries crucial for directed protein/peptide evolution. With the increased efficiency, this system was able to reduce the time for one selection cycle to cDNA display method. A three-finger protein library was evolved to isolate superior nanomolar range binding candidates for vascular endothelial growth factor. This method is expected to provide a beneficial impact to accelerated drug discovery and proteome analysis.

  9. Bactericidal effects of a fusion protein of llama heavy-chain antibodies coupled to glucose oxidase on oral bacteria.

    Science.gov (United States)

    Szynol, A; de Soet, J J; Sieben-van Tuyl, E; Bos, J W; Frenken, L G

    2004-09-01

    Enzymes such as lactoperoxidase and glucose oxidase (GOx) are used as antimicrobial agents in oral care products. Their low specificities and substantiveness can be reduced by covalent coupling of antimicrobial molecules to antibodies. Variable domains (V(HH)) derived from llama heavy-chain antibodies are particularly suited for such an approach. The antibodies are composed solely of heavy-chain dimers; therefore, production of active fusion proteins by using molecular biology-based techniques is less complicated than production by use of conventional antibodies. In this study, a fusion protein consisting of V(HH) and GOx was constructed and expressed by Saccharomyces cerevisiae. A llama was immunized with Streptococcus mutans strain HG982. Subsequently, B lymphocytes were isolated and cDNA fragments encoding the V(HH) fragments were obtained by reverse transcription-PCR. After construction of a V(HH) library in Escherichia coli and screening of the library against mutans group streptococci and Streptococcus sanguinis strains, we found two V(HH) fragments with high specificities for S. mutans strains. A GOx gene was linked to the two V(HH) genes and cloned into S. cerevisiae yeasts. The yeasts expressed and secreted the recombinant proteins into the growth medium. The test of binding of fusion proteins to oral bacteria through their V(HH) fragments showed that S. mutans had been specifically targeted by GOx-S120, one of the fusion protein constructs. A low concentration of the fusion protein was also able to selectively kill S. mutans within 20 min in the presence of lactoperoxidase and potassium iodide. These findings demonstrate that the fusion protein GOx-V(HH) is potentially valuable in the selective killing of target bacteria such as S. mutans.

  10. Expression, purification and characterization of hepatitis B virus X protein BH3-like motif-linker-Bcl-xL fusion protein for structural studies

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    Hideki Kusunoki

    2017-03-01

    Full Text Available Hepatitis B virus X protein (HBx is a multifunctional protein that interacts directly with many host proteins. For example, HBx interacts with anti-apoptotic proteins, Bcl-2 and Bcl-xL, through its BH3-like motif, which leads to elevated cytosolic calcium levels, efficient viral DNA replication and the induction of apoptosis. To facilitate sample preparation and perform detailed structural characterization of the complex between HBx and Bcl-xL, we designed and purified a recombinant HBx BH3-like motif-linker-Bcl-xL fusion protein produced in E. coli. The fusion protein was characterized by size exclusion chromatography, circular dichroism and nuclear magnetic resonance experiments. Our results show that the fusion protein is a monomer in aqueous solution, forms a stable intramolecular complex, and likely retains the native conformation of the complex between Bcl-xL and the HBx BH3-like motif. Furthermore, the HBx BH3-like motif of the intramolecular complex forms an α-helix. These observations indicate that the fusion protein should facilitate structural studies aimed at understanding the interaction between HBx and Bcl-xL at the atomic level.

  11. Microfilament dynamics during cell movement and chemotaxis monitored using a GFP-actin fusion protein.

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    Westphal, M; Jungbluth, A; Heidecker, M; Mühlbauer, B; Heizer, C; Schwartz, J M; Marriott, G; Gerisch, G

    1997-03-01

    The microfilament system in the cortex of highly motile cells, such as neutrophils and cells of the eukaryotic microorganism Dictyostelium discoideum, is subject to rapid re-organization, both spontaneously and in response to external signals. In particular, actin polymerization induced by a gradient of chemoattractant leads to local accumulation of filamentous actin and protrusion of a 'leading edge' of the cell in the direction of the gradient. In order to study the dynamics of actin in these processes, actin was tagged at its amino terminus with green fluorescent protein (GFP) and observed with fluorescence microscopy in living cells of D. discoideum. Purified GFP-actin was capable of copolymerizing with actin. In the transfected cells of D. discoideum studied, GFP-actin made up 10-20% of the total actin. Microfilaments containing GFP-actin were capable of generating force with myosin in an in vitro assay. Observations of single living cells using fluorescence microscopy showed that the fusion protein was enriched in cell projections, including filopodia and leading edges, and that the fusion protein reflected the dynamics of the microfilament system in cells that were freely moving, being chemotactically stimulated, or aggregated. When confocal sections of fixed cells containing GFP-actin were labeled with fluorescent phalloidin, which binds only to filamentous actin, there was a correlation between the areas of GFP-actin and phalloidin fluorescence, but there were distinct sites in which GFP-actin was more prominent. Double labeling with GFP-actin and other probes provides an indication of the various states of actin in motile cells. A major portion of the actin assemblies visualized using GFP-actin are networks or bundles of filamentous actin. Other clusters of GFP-actin might represent stores of monomeric actin in the form of complexes with actin-sequestering proteins.

  12. Chemical Screens Identify Drugs that Enhance or Mitigate Cellular Responses to Antibody-Toxin Fusion Proteins.

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    Antonella Antignani

    Full Text Available The intersection of small molecular weight drugs and antibody-based therapeutics is rarely studied in large scale. Both types of agents are currently part of the cancer armamentarium. However, very little is known about how to combine them in optimal ways. Immunotoxins are antibody-toxin gene fusion proteins engineered to target cancer cells via antibody binding to surface antigens. For fusion proteins derived from Pseudomonas exotoxin (PE, potency relies on the enzymatic domain of the toxin which catalyzes the ADP-ribosylation of EF2 causing inhibition of protein synthesis leading to cell death. Candidate immunotoxins have demonstrated clear value in clinical trials but generally have not been curative as single agents. Therefore we undertook three screens to discover effective combinations that could act synergistically. From the MIPE-3 library of compounds we identified various enhancers of immunotoxin action and at least one major class of inhibitor. Follow-up experiments confirmed the screening data and suggested that immunotoxins when administered with everolimus or nilotinib exhibit favorable combinatory activity and would be candidates for preclinical development. Mechanistic studies revealed that everolimus-immunotoxin combinations acted synergistically on elements of the protein synthetic machinery, including S61 kinase and 4E-BP1 of the mTORC1 pathway. Conversely, PARP inhibitors antagonized immunotoxins and also blocked the toxicity due to native ADP-ribosylating toxins. Thus, our goal of investigating a chemical library was justified based on the identification of several approved compounds that could be developed preclinically as 'enhancers' and at least one class of mitigator to be avoided.

  13. Dynamic in vivo imaging and cell tracking using a histone fluorescent protein fusion in mice

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    Papaioannou Virginia E

    2004-12-01

    Full Text Available Abstract Background Advances in optical imaging modalities and the continued evolution of genetically-encoded fluorescent proteins are coming together to facilitate the study of cell behavior at high resolution in living organisms. As a result, imaging using autofluorescent protein reporters is gaining popularity in mouse transgenic and targeted mutagenesis applications. Results We have used embryonic stem cell-mediated transgenesis to label cells at sub-cellular resolution in vivo, and to evaluate fusion of a human histone protein to green fluorescent protein for ubiquitous fluorescent labeling of nucleosomes in mice. To this end we have generated embryonic stem cells and a corresponding strain of mice that is viable and fertile and exhibits widespread chromatin-localized reporter expression. High levels of transgene expression are maintained in a constitutive manner. Viability and fertility of homozygous transgenic animals demonstrates that this reporter is developmentally neutral and does not interfere with mitosis or meiosis. Conclusions Using various optical imaging modalities including wide-field, spinning disc confocal, and laser scanning confocal and multiphoton excitation microscopy, we can identify cells in various stages of the cell cycle. We can identify cells in interphase, cells undergoing mitosis or cell death. We demonstrate that this histone fusion reporter allows the direct visualization of active chromatin in situ. Since this reporter segments three-dimensional space, it permits the visualization of individual cells within a population, and so facilitates tracking cell position over time. It is therefore attractive for use in multidimensional studies of in vivo cell behavior and cell fate.

  14. Mouse interleukin-12/FasTI: A novel bi-functional fusion protein for cancer immuno/gene therapy.

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    Yang, Xi; Tietje, Ashlee H; Yu, Xianzhong; Wei, Yanzhang

    2016-06-01

    Whereas cancer immunotherapy with cytokines in recent research was demonstrated effective in activating immune response against tumor cells, one major obstacle with the use of these cytokines is their severe side effects when delivered systemically at high doses. Another challenge is that advanced tumor cells often evade immunosurveillance of the immune system as well as of the Fas-mediated apoptosis by various mechanisms. We report the design and preliminary evaluation of the antitumor activity of a novel fusion protein-mIL-12/FasTI, consisting of mouse interleukin-12 and the transmembrane and intracellular domains of mouse Fas. The fusion construct (pmIL-12/FasTI) was transfected into mouse lung carcinoma cell line TC-1. Stable cell clones expressing the fusion protein were established as assayed by RT-PCR and immunohistochemistry. ELISA and cell proliferation analyses demonstrated that NK cells were effectively activated by the fusion protein with increased IFN-γ production and cytotoxicity. Enhanced caspase-3 activity of the clones when co-cultured with NK cells indicated that apoptosis was induced through Fas/FasL signaling pathway. The preliminary results suggest a synergized anticancer activity of the fusion protein. It may represent a promising therapeutic agent for cancer treatment.

  15. Cloning, Expression and Purification of the Recombinant HIV-1 Tat-Nef Fusion Protein in Prokaryotic Expression System

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    Somayeh Kadkhodayan

    2016-07-01

    Full Text Available Abstract Background: Nef is one of the HIV-1 critical proteins, because it is essential for viral replication and AIDS disease progression and induction of immune response against it can partially inhibit viral infection. Moreover, a domain of the HIV-1 Trans-Activator of Transcription (Tat, 48-60 aa could act as a cell penetrating peptide (CPP. In current study, cloning and expression of Tat-Nef fusion protein was performed in E. coli for the first time. The protein expression was confirmed by western blot analysis and was purified using reverse staining method. Materials and Methods: In this experimental study, primarily, cloning of Tat-Nef fusion gene was done in pGEX6p2 expression vector. Then, the expression of Tat-Nef recombinat protein in E.coli BL21 (DE3 strain was performed by using IPTG inducer. The protein expression was confirmed by SDS-PAGE and western blotting using anti-Nef monoclonal antibody. Then, the recombinant fusion protein was purified from gel using reverse staining method. Results: The results of PCR analysis and enzyme digestion showed a clear band of ~ 726 bp in agarose gel indicating the correct Tat-Nef fusion cloning in pGEX6p2 prokaryotic expression vector. In addition, a 54 kDa band of Tat-Nef on SDS-PAGE revealed Tat-Nef protein expression that western blot analysis using anti-Nef monoclonal antibody confirmed it. Conclusion: The purified Tat-Nef recombinant fusion protein will be used as an antigen for protein vaccine design against HIV infection.

  16. Molecular epidemiology and phylodynamics of the human respiratory syncytial virus fusion protein in northern Taiwan.

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    Hsin Chi

    Full Text Available BACKGROUND AND AIMS: The glycoprotein (G protein and fusion protein (F protein of respiratory syncytial virus (RSV both show genetic variability, but few studies have examined the F protein gene. This study aimed to characterize the molecular epidemiology and phylodynamics of the F protein gene in clinical RSV strains isolated in northern Taiwan from 2000-2011. METHODS: RSV isolates from children presenting with acute respiratory symptoms between July 2000 and June 2011 were typed based on F protein gene sequences. Phylogeny construction and evaluation were performed using the neighbor-joining (NJ and maximum likelihood (ML methods. Phylodynamic patterns in RSV F protein genes were analyzed using the Bayesian Markov Chain Monte Carlo framework. Selection pressure on the F protein gene was detected using the Datamonkey website interface. RESULTS: From a total of 325 clinical RSV strains studied, phylogenetic analysis showed that 83 subgroup A strains (RSV-A could be further divided into three clusters, whereas 58 subgroup B strains (RSV-B had no significant clustering. Three amino acids were observed to differ between RSV-A and -B (positions 111, 113, and 114 in CTL HLA-B*57- and HLA-A*01-restricted epitopes. One positive selection site was observed in RSV-B, while none was observed in RSV-A. The evolution rate of the virus had very little change before 2000, then slowed down between 2000 and 2005, and evolved significantly faster after 2005. The dominant subtypes of RSV-A in each epidemic were replaced by different subtypes in the subsequent epidemic. CONCLUSIONS: Before 2004, RSV-A infections were involved in several small epidemics and only very limited numbers of strains evolved and re-emerged in subsequent years. After 2005, the circulating RSV-A strains were different from those of the previous years and continued evolving through 2010. Phylodynamic pattern showed the evolutionary divergence of RSV increased significantly in the recent 5

  17. An alternative easy method for antibody purification and analysis of protein-protein interaction using GST fusion proteins immobilized onto glutathione-agarose.

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    Zalazar, L; Alonso, C A I; De Castro, R E; Cesari, A

    2014-01-01

    Immobilization of small proteins designed to perform protein-protein assays can be a difficult task. Often, the modification of reactive residues necessary for the interaction between the immobilized protein and the matrix compromises the interaction between the protein and its target. In these cases, glutathione-S-transferase (GST) is a valuable tag providing a long arm that makes the bait protein accessible to the mobile flow phase of the chromatography. In the present report, we used a GST fusion version of the 8-kDa protein serine protease inhibitor Kazal-type 3 (SPINK3) as the bait to purify anti-SPINK3 antibodies from a rabbit crude serum. The protocol for immobilization of GST-SPINK3 to glutathione-agarose beads was modified from previously reported protocols by using an alternative bifunctional cross-linker (dithiobis(succinimidyl propionate)) in a very simple procedure and by using simple buffers under physiological conditions. We concluded that the immobilized protein remained bound to the column after elution with low pH, allowing the reuse of the column for alternative uses, such as screening for other protein-protein interactions using SPINK3 as the bait.

  18. Murine analogues of etanercept and of F8-IL10 inhibit the progression of collagen-induced arthritis in the mouse.

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    Doll, Fabia; Schwager, Kathrin; Hemmerle, Teresa; Neri, Dario

    2013-09-27

    Etanercept is a fusion protein consisting of the soluble portion of the p75-tumor necrosis factor receptor (TNFR) and the Fc fragment of human IgG1, which is often used for the treatment of patients with rheumatoid arthritis. F8-IL10 is a human immunocytokine based on the F8 antibody and interleukin-10, which is currently being investigated in rheumatoid arthritis with promising clinical results. We have aimed at expressing murine versions of these two fusion proteins, in order to assess their pharmaceutical performance in the collagen-induced model of rheumatoid arthritis in the mouse. Two fusion proteins (termed muTNFR-Fc and F8-muIL10) were cloned, expressed in chinese hamster ovary (CHO) cells, purified and characterized. Biological activity of muTNFR-Fc was assessed by its ability to inhibit TNF-induced killing of mouse fibroblasts, while F8-muIL10 was characterized in terms of muIL10 activity, of binding affinity to the cognate antigen of F8, the alternatively-spliced EDA domain of fibronectin, by quantitative biodistribution analysis and in vivo imaging. The therapeutic activity of both fusion proteins was investigated in a collagen-induced mouse model of arthritis. Mouse plasma was analyzed for anti-drug antibody formation and cytokine levels were determined by bead-based multiplex technology. The association of F8-IL10 proteins with blood cells was studied in a centrifugation assay with radiolabeled protein. Both fusion proteins exhibited excellent purity and full biological activity in vitro. In addition, F8-muIL10 was able to localize on newly-formed blood vessels in vivo. When used in a murine model of arthritis, the two proteins inhibited arthritis progression. The activity of muTNFR-Fc was tested alone and in combination with F8-huIL10. The chimeric version of F8-IL10 was not better then the fully human fusion protein and showed similar generation of mouse anti-fusion protein antibodies. Incubation studies of F8-muIL10 and F8-huIL10 with blood

  19. Protein/peptide-based entry/fusion inhibitors as anti-HIV therapies: challenges and future direction.

    Science.gov (United States)

    Fumakia, Miral; Yang, Sidi; Gu, Jijin; Ho, Emmanuel A

    2016-01-01

    The failures of several first-generation and second-generation small molecule drug-based anti-HIV therapies in various stages of clinical trials are an indication that there is a need for a paradigm shift in the future designs of anti-HIV therapeutics. Over the past several decades, various anti-HIV drugs have been developed, among them, protein/peptide-based therapies. From the first peptide discovered (SJ2176) to the first peptide approved by the Food and Drug Administration (DP178/T20/enfuvirtide/Fuzeon®), anti-HIV proteins/peptides as fusion/entry inhibitors have been shown to provide potent effects and benefits. This review summarizes the past and current endeavors in this area, discusses the potential mechanisms of action for various anti-HIV proteins/peptides, compares the advantages and disadvantages between the different proteins/peptides, and finally, examines the future direction of the field, specifically, strategies that will enhance the therapeutic efficacy of fusion/entry inhibitor-based anti-HIV proteins/peptides. Although there are numerous reviews highlighting the general field of entry/fusion inhibitors, there is a lack of literature focused on protein/peptide-based entry/fusion inhibitors for HIV therapy, and as a result, this review is intended to fill this void by summarizing the past, current, and future development of these macromolecules. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  20. Escherichia coli EDA is a novel fusion expression partner to improve solubility of aggregation-prone heterologous proteins.

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    Kang, Yoon-Sik; Song, Jong-Am; Han, Kyung-Yeon; Lee, Jeewon

    2015-01-20

    Since the use of solubility enhancer proteins is one of the effective methods to produce active recombinant proteins within Escherichia coli, the development of a novel fusion expression partner that can be applied to various aggregation-prone proteins is of crucial importance. In our previous work, two-dimensional electrophoresis (2-DE) was employed to systematically analyze the E. coli BL21 (DE3) proteome profile in response to heat treatment, and KDPG aldolase (EDA) was identified as a heat-responsive and aggregation-resistant protein. When used as fusion expression partner, EDA significantly increased the solubility of seven aggregation-prone heterologous proteins in the E. coli cytoplasm. The efficacy of EDA as a fusion expression partner was evaluated through the analysis of bioactivity or secondary structure of several target proteins: EDA-fusion expression resulted in the synthesis of bioactive human ferritin light chain and bacterial arginine deiminase and the formation of correct secondary structure of human granulocyte colony stimulation factor. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Optimizing HIV-1 protease production in Escherichia coli as fusion protein.

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    Volontè, Federica; Piubelli, Luciano; Pollegioni, Loredano

    2011-06-30

    Human immunodeficiency virus (HIV) is the etiological agent in AIDS and related diseases. The aspartyl protease encoded by the 5' portion of the pol gene is responsible for proteolytic processing of the gag-pol polyprotein precursor to yield the mature capsid protein and the reverse transcriptase and integrase enzymes. The HIV protease (HIV-1Pr) is considered an attractive target for designing inhibitors which could be used to tackle AIDS and therefore it is still the object of a number of investigations. A recombinant human immunodeficiency virus type 1 protease (HIV-1Pr) was overexpressed in Escherichia coli cells as a fusion protein with bacterial periplasmic protein dithiol oxidase (DsbA) or glutathione S-transferase (GST), also containing a six-histidine tag sequence. Protein expression was optimized by designing a suitable HIV-1Pr cDNA (for E. coli expression and to avoid autoproteolysis) and by screening six different E. coli strains and five growth media. The best expression yields were achieved in E. coli BL21-Codon Plus(DE3)-RIL host and in TB or M9 medium to which 1% (w/v) glucose was added to minimize basal expression. Among the different parameters assayed, the presence of a buffer system (based on phosphate salts) and a growth temperature of 37°C after adding IPTG played the main role in enhancing protease expression (up to 10 mg of chimeric DsbA:HIV-1Pr/L fermentation broth). GST:HIVPr was in part (50%) produced as soluble protein while the overexpressed DsbA:HIV-1Pr chimeric protein largely accumulated in inclusion bodies as unprocessed fusion protein. A simple refolding procedure was developed on HiTrap Chelating column that yielded a refolded DsbA:HIV-1Pr with a > 80% recovery. Finally, enterokinase digestion of resolubilized DsbA:HIV-1Pr gave more than 2 mg of HIV-1Pr per liter of fermentation broth with a purity ≤ 80%, while PreScission protease cleavage of soluble GST:HIVPr yielded ~ 0.15 mg of pure HIV-1Pr per liter. By using this optimized

  2. Optimizing HIV-1 protease production in Escherichia coli as fusion protein

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    Piubelli Luciano

    2011-06-01

    Full Text Available Abstract Background Human immunodeficiency virus (HIV is the etiological agent in AIDS and related diseases. The aspartyl protease encoded by the 5' portion of the pol gene is responsible for proteolytic processing of the gag-pol polyprotein precursor to yield the mature capsid protein and the reverse transcriptase and integrase enzymes. The HIV protease (HIV-1Pr is considered an attractive target for designing inhibitors which could be used to tackle AIDS and therefore it is still the object of a number of investigations. Results A recombinant human immunodeficiency virus type 1 protease (HIV-1Pr was overexpressed in Escherichia coli cells as a fusion protein with bacterial periplasmic protein dithiol oxidase (DsbA or glutathione S-transferase (GST, also containing a six-histidine tag sequence. Protein expression was optimized by designing a suitable HIV-1Pr cDNA (for E. coli expression and to avoid autoproteolysis and by screening six different E. coli strains and five growth media. The best expression yields were achieved in E. coli BL21-Codon Plus(DE3-RIL host and in TB or M9 medium to which 1% (w/v glucose was added to minimize basal expression. Among the different parameters assayed, the presence of a buffer system (based on phosphate salts and a growth temperature of 37°C after adding IPTG played the main role in enhancing protease expression (up to 10 mg of chimeric DsbA:HIV-1Pr/L fermentation broth. GST:HIVPr was in part (50% produced as soluble protein while the overexpressed DsbA:HIV-1Pr chimeric protein largely accumulated in inclusion bodies as unprocessed fusion protein. A simple refolding procedure was developed on HiTrap Chelating column that yielded a refolded DsbA:HIV-1Pr with a > 80% recovery. Finally, enterokinase digestion of resolubilized DsbA:HIV-1Pr gave more than 2 mg of HIV-1Pr per liter of fermentation broth with a purity ≤ 80%, while PreScission protease cleavage of soluble GST:HIVPr yielded ~ 0.15 mg of pure HIV-1

  3. Enhancing the solubility of recombinant proteins in Escherichia coli by using hexahistidine-tagged maltose-binding protein as a fusion partner.

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    Sun, Ping; Tropea, Joseph E; Waugh, David S

    2011-01-01

    In the field of biotechnology, fusing recombinant proteins to highly soluble partners is a common practice for overcoming aggregation in Escherichia coli. E. coli maltose-binding protein (MBP) has been recognized as one of the most effective solubilizing agents, having frequently been observed to improve the yield, enhance the solubility, and promote the proper folding of its fusion partners. The use of a dual hexahistidine-maltose-binding protein affinity tag (His(6)-MBP) has the additional advantage of allowing the fusion protein to be purified by immobilized metal affinity chromatography (IMAC) instead of or in addition to amylose affinity chromatography. This chapter describes a generic method for the overproduction of combinatorially tagged His(6)-MBP fusion proteins in E. coli, with particular emphasis on the use of recombinational cloning to construct expression vectors. In addition, simple methods for evaluating the solubility of the fusion protein and the passenger protein after it is cleaved from the dual His(6)-MBP tag are presented.

  4. Tethering of the conserved piggyBac transposase fusion protein CSB-PGBD3 to chromosomal AP-1 proteins regulates expression of nearby genes in humans.

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    Gray, Lucas T; Fong, Kimberly K; Pavelitz, Thomas; Weiner, Alan M

    2012-09-01

    The CSB-PGBD3 fusion protein arose more than 43 million years ago when a 2.5-kb piggyBac 3 (PGBD3) transposon inserted into intron 5 of the Cockayne syndrome Group B (CSB) gene in the common ancestor of all higher primates. As a result, full-length CSB is now coexpressed with an abundant CSB-PGBD3 fusion protein by alternative splicing of CSB exons 1-5 to the PGBD3 transposase. An internal deletion of the piggyBac transposase ORF also gave rise to 889 dispersed, 140-bp MER85 elements that were mobilized in trans by PGBD3 transposase. The CSB-PGBD3 fusion protein binds MER85s in vitro and induces a strong interferon-like innate antiviral immune response when expressed in CSB-null UVSS1KO cells. To explore the connection between DNA binding and gene expression changes induced by CSB-PGBD3, we investigated the genome-wide DNA binding profile of the fusion protein. CSB-PGBD3 binds to 363 MER85 elements in vivo, but these sites do not correlate with gene expression changes induced by the fusion protein. Instead, CSB-PGBD3 is enriched at AP-1, TEAD1, and CTCF motifs, presumably through protein-protein interactions with the cognate transcription factors; moreover, recruitment of CSB-PGBD3 to AP-1 and TEAD1 motifs correlates with nearby genes regulated by CSB-PGBD3 expression in UVSS1KO cells and downregulated by CSB rescue of mutant CS1AN cells. Consistent with these data, the N-terminal CSB domain of the CSB-PGBD3 fusion protein interacts with the AP-1 transcription factor c-Jun and with RNA polymerase II, and a chimeric CSB-LacI construct containing only the N-terminus of CSB upregulates many of the genes induced by CSB-PGBD3. We conclude that the CSB-PGBD3 fusion protein substantially reshapes the transcriptome in CS patient CS1AN and that continued expression of the CSB-PGBD3 fusion protein in the absence of functional CSB may affect the clinical presentation of CS patients by directly altering the transcriptional program.

  5. Tethering of the conserved piggyBac transposase fusion protein CSB-PGBD3 to chromosomal AP-1 proteins regulates expression of nearby genes in humans.

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    Lucas T Gray

    2012-09-01

    Full Text Available The CSB-PGBD3 fusion protein arose more than 43 million years ago when a 2.5-kb piggyBac 3 (PGBD3 transposon inserted into intron 5 of the Cockayne syndrome Group B (CSB gene in the common ancestor of all higher primates. As a result, full-length CSB is now coexpressed with an abundant CSB-PGBD3 fusion protein by alternative splicing of CSB exons 1-5 to the PGBD3 transposase. An internal deletion of the piggyBac transposase ORF also gave rise to 889 dispersed, 140-bp MER85 elements that were mobilized in trans by PGBD3 transposase. The CSB-PGBD3 fusion protein binds MER85s in vitro and induces a strong interferon-like innate antiviral immune response when expressed in CSB-null UVSS1KO cells. To explore the connection between DNA binding and gene expression changes induced by CSB-PGBD3, we investigated the genome-wide DNA binding profile of the fusion protein. CSB-PGBD3 binds to 363 MER85 elements in vivo, but these sites do not correlate with gene expression changes induced by the fusion protein. Instead, CSB-PGBD3 is enriched at AP-1, TEAD1, and CTCF motifs, presumably through protein-protein interactions with the cognate transcription factors; moreover, recruitment of CSB-PGBD3 to AP-1 and TEAD1 motifs correlates with nearby genes regulated by CSB-PGBD3 expression in UVSS1KO cells and downregulated by CSB rescue of mutant CS1AN cells. Consistent with these data, the N-terminal CSB domain of the CSB-PGBD3 fusion protein interacts with the AP-1 transcription factor c-Jun and with RNA polymerase II, and a chimeric CSB-LacI construct containing only the N-terminus of CSB upregulates many of the genes induced by CSB-PGBD3. We conclude that the CSB-PGBD3 fusion protein substantially reshapes the transcriptome in CS patient CS1AN and that continued expression of the CSB-PGBD3 fusion protein in the absence of functional CSB may affect the clinical presentation of CS patients by directly altering the transcriptional program.

  6. Antibody fusions with fluorescent proteins: a versatile reagent for profiling protein expression.

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    Morino, K; Katsumi, H; Akahori, Y; Iba, Y; Shinohara, M; Ukai, Y; Kohara, Y; Kurosawa, Y

    2001-11-01

    We developed a system by which antibodies, fused to fluorescent proteins with different wavelengths, can be prepared within a month against various antigens. An antibody library composed of a large number of single-chain Fv-CL fragment was constructed by means of a phage-display system. The constructs were designed to facilitate changing of the protein forms by simple enzyme manipulation. In the present study, we adopted a molecular form of antibody in which a single-chain Fv-CL fragment is fused with a green fluorescent protein (GFP) or red fluorescent protein (RFP). In addition, a His-tag was inserted between CL and GFP (or RFP). We describe the utility of this system using Caenorhabditis elegans embryo as a model.

  7. Incorporation of albumin fusion proteins into fibrin clots in vitro and in vivo: comparison of different fusion motifs recognized by factor XIIIa

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    Sheffield William P

    2011-12-01

    Full Text Available Abstract Background The transglutaminase activated factor XIII (FXIIIa acts to strengthen pathological fibrin clots and to slow their dissolution, in part by crosslinking active α2-antiplasmin (α2AP to fibrin. We previously reported that a yeast-derived recombinant fusion protein comprising α2AP residues 13-42 linked to human serum albumin (HSA weakened in vitro clots but failed to become specifically incorporated into in vivo clots. In this study, our aims were to improve both the stability and clot localization of the HSA fusion protein by replacing α2AP residues 13-42 with shorter sequences recognized more effectively by FXIIIa. Results Expression plasmids were prepared encoding recombinant HSA with the following N-terminal 23 residue extensions: H6NQEQVSPLTLLAG4Y (designated XL1; H6DQMMLPWAVTLG4Y (XL2; H6WQHKIDLPYNGAG4Y (XL3; and their 17 residue non-His-tagged equivalents (XL4, XL5, and XL6. The HSA moiety of XL4- to XL6-HSA proteins was C-terminally His-tagged. All chimerae were efficiently secreted from transformed Pichia pastoris yeast except XL3-HSA, and following nickel chelate affinity purification were found to be intact by amino acid sequencing, as was an N-terminally His-tagged version of α2AP(13-42-HSA. Of the proteins tested, XL5-HSA was cross-linked to biotin pentylamine (BPA most rapidly by FXIIIa, and was the most effective competitor of α2AP crosslinking not only to BPA but also to plasma fibrin clots. In the mouse ferric chloride vena cava thrombosis model, radiolabeled XL5-HSA was retained in the clot to a greater extent than recombinant HSA. In the rabbit jugular vein stasis thrombosis model, XL5-HSA was also retained in the clot, in a urea-insensitive manner indicative of crosslinking to fibrin, to a greater extent than recombinant HSA. Conclusions Fusion protein XL5-HSA (DQMMLPWAVTLG4Y-HSAH6 was found to be more active as a substrate for FXIIIa-mediated transamidation than seven other candidate fusion proteins in

  8. Hexahistidine-tagged maltose-binding protein as a fusion partner for the production of soluble recombinant proteins in Escherichia coli.

    Science.gov (United States)

    Austin, Brian P; Nallamsetty, Sreedevi; Waugh, David S

    2009-01-01

    Insolubility of recombinant proteins in Escherichia coli is a major impediment to their production for structural and functional studies. One way to circumvent this problem is to fuse an aggregation-prone protein to a highly soluble partner. E. coli maltose-binding protein (MBP) has emerged as one of the most effective solubilizing agents. In this chapter, we describe how to construct combinatorially-tagged His(6)MBP fusion proteins by recombinational cloning and how to evaluate their yield and solubility. We also describe a procedure to determine how efficiently a His(6)MBP fusion protein is cleaved by tobacco etch virus (TEV) protease in E. coli and a method to assess the solubility of the target protein after it has been separated from His(6)MBP.

  9. Palmitoylation of SARS-CoV S protein is necessary for partitioning into detergent-resistant membranes and cell-cell fusion but not interaction with M protein

    International Nuclear Information System (INIS)

    McBride, Corrin E.; Machamer, Carolyn E.

    2010-01-01

    Coronaviruses are enveloped RNA viruses that generally cause mild disease in humans. However, the recently emerged coronavirus that caused severe acute respiratory syndrome (SARS-CoV) is the most pathogenic human coronavirus discovered to date. The SARS-CoV spike (S) protein mediates virus entry by binding cellular receptors and inducing fusion between the viral envelope and the host cell membrane. Coronavirus S proteins are palmitoylated, which may affect function. Here, we created a non-palmitoylated SARS-CoV S protein by mutating all nine cytoplasmic cysteine residues. Palmitoylation of SARS-CoV S was required for partitioning into detergent-resistant membranes and for cell-cell fusion. Surprisingly, however, palmitoylation of S was not required for interaction with SARS-CoV M protein. This contrasts with the requirement for palmitoylation of mouse hepatitis virus S protein for interaction with M protein and may point to important differences in assembly and infectivity of these two coronaviruses.

  10. Stimulated emission depletion nanoscopy of living cells using SNAP-tag fusion proteins.

    Science.gov (United States)

    Hein, Birka; Willig, Katrin I; Wurm, Christian A; Westphal, Volker; Jakobs, Stefan; Hell, Stefan W

    2010-01-06

    We show far-field fluorescence nanoscopy of different structural elements labeled with an organic dye within living mammalian cells. The diffraction barrier limiting far-field light microscopy is outperformed by using stimulated emission depletion. We used the tagging protein hAGT (SNAP-tag), which covalently binds benzylguanine-substituted organic dyes, for labeling. Tetramethylrhodamine was used to image the cytoskeleton (vimentin and microtubule-associated protein 2) as well as structures located at the cell membrane (caveolin and connexin-43) with a resolution down to 40 nm. Comparison with structures labeled with the yellow fluorescent protein Citrine validates this labeling approach. Nanoscopic movies showing the movement of connexin-43 clusters across the cell membrane evidence the capability of this technique to observe structural changes on the nanoscale over time. Pulsed or continuous-wave lasers for excitation and stimulated emission depletion yield images of similar resolution in living cells. Hence fusion proteins that bind modified organic dyes expand widely the application range of far-field fluorescence nanoscopy of living cells. Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  11. Nuclei of non-muscle cells bind centrosome proteins upon fusion with differentiating myoblasts.

    Directory of Open Access Journals (Sweden)

    Xavier Fant

    2009-12-01

    Full Text Available In differentiating myoblasts, the microtubule network is reorganized from a centrosome-bound, radial array into parallel fibres, aligned along the long axis of the cell. Concomitantly, proteins of the centrosome relocalize from the pericentriolar material to the outer surface of the nucleus. The mechanisms that govern this relocalization are largely unknown.In this study, we perform experiments in vitro and in cell culture indicating that microtubule nucleation at the centrosome is reduced during myoblast differentiation, while nucleation at the nuclear surface increases. We show in heterologous cell fusion experiments, between cultures of differentiating mouse myoblasts and human cells of non-muscular origin, that nuclei from non-muscle cells recruit centrosome proteins once fused with the differentiating myoblasts. This recruitment still occurs in the presence of cycloheximide and thus appears to be independent of new protein biosynthesis.Altogether, our data suggest that nuclei of undifferentiated cells have the dormant potential to bind centrosome proteins, and that this potential becomes activated during myoblast differentiation.

  12. Antigen Binding and Site-Directed Labeling of Biosilica-Immobilized Fusion Proteins Expressed in Diatoms

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Nicole R.; Hecht, Karen A.; Hu, Dehong; Orr, Galya; Xiong, Yijia; Squier, Thomas; Rorrer, Gregory L.; Roesijadi, Guritno

    2016-01-08

    The diatom Thalassiosira pseudonana was genetically modified to express biosilica-targeted fusion proteins incorporating a tetracysteine tag for site-directed labeling with biarsenical affinity probes and either EGFP or single chain antibody to test colocalization of probes with the EGFP-tagged recombinant protein or binding of biosilica-immobilized antibodies to large and small molecule antigens, respectively. Site-directed labeling with the biarsenical probes demonstrated colocalization with EGFP-encoded proteins in nascent and mature biosilica, supporting their use in studying biosilica maturation. Isolated biosilica transformed with a single chain antibody against either the Bacillus anthracis surface layer protein EA1 or small molecule explosive trinitrotoluene (TNT) effectively bound the respective antigens. A marked increase in fluorescence lifetime of the TNT surrogate Alexa Fluor 555-trinitrobenzene reflected the high binding specificity of the transformed isolated biosilica. These results demonstrated the potential use of biosilica-immobilized single chain antibodies as binders for large and small molecule antigens in sensing and therapeutics.

  13. Characterization of the Klebsiella aerogenes urease accessory protein UreD in fusion with the maltose binding protein.

    Science.gov (United States)

    Carter, Eric L; Hausinger, Robert P

    2010-05-01

    Assembly of the Klebsiella aerogenes urease metallocenter requires four accessory proteins, UreD, UreE, UreF, and UreG, to effectively deliver and incorporate two Ni2+ ions into the nascent active site of the urease apoprotein (UreABC). Each accessory protein has been purified and characterized with the exception of UreD due to its insolubility when it is overproduced in recombinant cells. In this study, a translational fusion was made between the maltose binding protein (MBP) and UreD, with the resulting MBP-UreD found to be soluble in Escherichia coli cell extracts and able to complement a DeltaureD-urease cluster in this host microorganism. MBP-UreD was purified as a large multimer (> 670 kDa) that bound approximately 2.5 Ni2+ ions (K(d) of approximately 50 microM, where K(d) is the dissociation constant) per UreD protomer according to equilibrium dialysis measurements. Zn2+ directly competes with 10-fold higher affinity (approximately 4 Zn2+ ions per protomer; K(d) of 5 microM) for the Ni2+ binding sites. MBP pulldown experiments demonstrated that the UreD domain of MBP-UreD formed in vivo complexes with UreF, UreG, UreF plus UreG, or UreABC when these proteins were overproduced in the same E. coli cells. In addition, a UreABC-(MBP-UreD)-UreFG complex was observed in cells producing all urease components. Comparative in vitro binding experiments with purified proteins demonstrated an approximate 1:1 binding ratio between the UreD domain of MBP-UreD and the UreF domain of the UreEF fusion, only weak or transient interaction between MBP-UreD and UreG, and no binding with UreABC. These studies are the first to describe the properties of purified UreD, and they extend our understanding of its binding partners both in vitro and in the cell.

  14. 5-Fluorocytosine combined with Fcy–hEGF fusion protein targets EGFR-expressing cancer cells

    International Nuclear Information System (INIS)

    Lan, Keng-Hsueh; Shih, Yi-Sheng; Chang, Cheng Allen; Yen, Sang-Hue; Lan, Keng-Li

    2012-01-01

    Highlights: ► EGFR-expressing epithelial cancers account for significant portion of cancer deaths. ► EGF–EGFR signaling pathway is validated as an important anticancer drug target. ► EGF and Fcy fusion protein (Fcy–hEGF) can bind to EGFR and convert 5-FC to 5-FU. ► Fcy–hEGF combined with 5-FC preferentially inhibits EGFR-expressing cells viability. -- Abstract: Human epithelial cancers account for approximately 50% of all cancer deaths. This type of cancer is characterized by excessive activation and expression of the epidermal growth factor receptor (EGFR). The EGFR pathway is critical for cancer cell proliferation, survival, metastasis and angiogenesis. The EGF–EGFR signaling pathway has been validated as an important anticancer drug target. Increasing numbers of targeted therapies against this pathway have been either approved or are currently under development. Here, we adopted a prodrug system that uses 5-fluorocytosine (5-FC) and human EGF (hEGF) fused with yeast cytosine deaminase (Fcy) to target EGFR-overexpressing cancer cells and to convert 5-FC to a significantly more toxic chemotherapeutic, 5-fluorouracil (5-FU). We cloned and purified the Fcy–hEGF fusion protein from Pichia pastoris yeast. This fusion protein specifically binds to EGFR with a similar affinity as hEGF, approximately 10 nM. Fcy–hEGF binds tightly to A431 and MDA-MB-468 cells, which overexpress EGFR, but it binds with a lower affinity to MDA-MB-231 and MCF-7, which express lower levels of EGFR. Similarly, the viability of EGFR-expressing cells was suppressed by Fcy–hEGF in the presence of increasing concentrations of 5-FC, and the IC 50 values for A431 and MDA-MB-468 were approximately 10-fold lower than those of MDA-MB-231 and MCF-7. This novel prodrug system, Fcy–hEGF/5-FC, might represent a promising addition to the available class of inhibitors that specifically target EGFR-expressing cancers.

  15. Fusion proteins of an enoate reductase and a Baeyer-Villiger monooxygenase facilitate the synthesis of chiral lactones.

    Science.gov (United States)

    Peters, Christin; Rudroff, Florian; Mihovilovic, Marko D; T Bornscheuer, Uwe

    2017-01-01

    Nature uses the advantages of fusion proteins for multi-step reactions to facilitate the metabolism in cells as the conversion of substrates through intermediates to the final product can take place more rapidly and with less side-product formation. In a similar fashion, also for enzyme cascade reactions, the fusion of biocatalysts involved can be advantageous. In the present study, we investigated fusion of an alcohol dehydrogenase (ADH), an enoate reductase (ERED) and a Baeyer-Villiger monooxygenase (BVMO) to enable the synthesis of (chiral) lactones starting from unsaturated alcohols as substrates. The domain order and various linkers were studied to find optimal conditions with respect to expression levels and enzymatic activities. Best results were achieved for the ERED xenobiotic reductase B (XenB) from Pseudomonas putida and the cyclohexanone monooxygenase (CHMO) from Acinetobacter sp., whereas none of the ADHs studied could be fused successfully. This fusion protein together with separately supplied ADH resulted in similar reaction rates in in vivo biocatalysis reactions. After 1.5 h we could detect 40% more dihydrocarvone lactone in in vivo reactions with the fusion protein and ADH then with the single enzymes.

  16. A plasmid toolkit for cloning chimeric cDNAs encoding customized fusion proteins into any Gateway destination expression vector

    Science.gov (United States)

    2013-01-01

    Background Valuable clone collections encoding the complete ORFeomes for some model organisms have been constructed following the completion of their genome sequencing projects. These libraries are based on Gateway cloning technology, which facilitates the study of protein function by simplifying the subcloning of open reading frames (ORF) into any suitable destination vector. The expression of proteins of interest as fusions with functional modules is a frequent approach in their initial functional characterization. A limited number of Gateway destination expression vectors allow the construction of fusion proteins from ORFeome-derived sequences, but they are restricted to the possibilities offered by their inbuilt functional modules and their pre-defined model organism-specificity. Thus, the availability of cloning systems that overcome these limitations would be highly advantageous. Results We present a versatile cloning toolkit for constructing fully-customizable three-part fusion proteins based on the MultiSite Gateway cloning system. The fusion protein components are encoded in the three plasmids integral to the kit. These can recombine with any purposely-engineered destination vector that uses a heterologous promoter external to the Gateway cassette, leading to the in-frame cloning of an ORF of interest flanked by two functional modules. In contrast to previous systems, a third part becomes available for peptide-encoding as it no longer needs to contain a promoter, resulting in an increased number of possible fusion combinations. We have constructed the kit’s component plasmids and demonstrate its functionality by providing proof-of-principle data on the expression of prototype fluorescent fusions in transiently-transfected cells. Conclusions We have developed a toolkit for creating fusion proteins with customized N- and C-term modules from Gateway entry clones encoding ORFs of interest. Importantly, our method allows entry clones obtained from ORFeome

  17. Optimization of proximity ligation assay (PLA) for detection of protein interactions and fusion proteins in non-adherent cells: application to pre-B lymphocytes.

    Science.gov (United States)

    Debaize, Lydie; Jakobczyk, Hélène; Rio, Anne-Gaëlle; Gandemer, Virginie; Troadec, Marie-Bérengère

    2017-01-01

    Genetic abnormalities, including chromosomal translocations, are described for many hematological malignancies. From the clinical perspective, detection of chromosomal abnormalities is relevant not only for diagnostic and treatment purposes but also for prognostic risk assessment. From the translational research perspective, the identification of fusion proteins and protein interactions has allowed crucial breakthroughs in understanding the pathogenesis of malignancies and consequently major achievements in targeted therapy. We describe the optimization of the Proximity Ligation Assay (PLA) to ascertain the presence of fusion proteins, and protein interactions in non-adherent pre-B cells. PLA is an innovative method of protein-protein colocalization detection by molecular biology that combines the advantages of microscopy with the advantages of molecular biology precision, enabling detection of protein proximity theoretically ranging from 0 to 40 nm. We propose an optimized PLA procedure. We overcome the issue of maintaining non-adherent hematological cells by traditional cytocentrifugation and optimized buffers, by changing incubation times, and modifying washing steps. Further, we provide convincing negative and positive controls, and demonstrate that optimized PLA procedure is sensitive to total protein level. The optimized PLA procedure allows the detection of fusion proteins and protein interactions on non-adherent cells. The optimized PLA procedure described here can be readily applied to various non-adherent hematological cells, from cell lines to patients' cells. The optimized PLA protocol enables detection of fusion proteins and their subcellular expression, and protein interactions in non-adherent cells. Therefore, the optimized PLA protocol provides a new tool that can be adopted in a wide range of applications in the biological field.

  18. Production of disulfide bond-rich peptides by fusion expression using small transmembrane proteins of Escherichia coli.

    Science.gov (United States)

    Chang, Ziwei; Lu, Ming; Ma, Yunqi; Kwag, Dong-Geon; Kim, Seo-Hyun; Park, Ji-Min; Nam, Bo-Hye; Kim, Young-Ok; An, Cheul-Min; Li, Huayue; Jung, Jee H; Park, Jang-Su

    2015-03-01

    Recombinant expression in Escherichia coli allows the simple, economical, and effective production of bioactive peptides. On the other hand, the production of native peptides, particularly those rich in disulfide bonds, is a major problem. Previous studies have reported that the use of carrier proteins for fusion expression can result in good peptide yields, but few are folded correctly. In this study, two transmembrane small proteins in E. coli, YoaJ and YkgR, which both orientate with their N-termini in cytoplasm and their C-termini in periplasm, were used for fusion expression. The recombinant production of two peptides, asteropsin A (ASPA) and β-defensin (BD), was induced in the periplasm of E. coli using a selected carrier protein. Both peptides were expressed at high levels, at yields of approximately 5-10 mg/L of culture. Mass spectrometry showed that the resulting peptide had the same molecular weight as their natural forms. After purification, single peaks were observed by reversed phase high-performance liquid chromatography (RP-HPLC), demonstrating the absence of isoforms. Furthermore, cytoplasmically expressed fusion proteins with a carrier at their C-termini did not contain disulfide bonds. This study provides new carrier proteins for fusion expression of disulfide bond-rich peptides in E. coli.

  19. Plasmid for the direct subcloning from lambda gt11 to produce an LT-B fusion protein.

    Science.gov (United States)

    Meinersmann, R J; Khoury, C A

    1994-06-01

    We wished to study LT-B fusion proteins for potential as vaccines. We reasoned that a gene that was expressed as a lambda gt11 fusion protein would have a better chance of being expressed fused to LT-B. To facilitate such constructions, we modified plasmid pYA3081. A BamHI-EcoRI-BamHI* (* is to stop codon) adapter was inserted into the single BamHI site to form a new plasmid-designated pBEB. The insert was designed so that the EcoRI site at the downstream end of the LT-B gene was in the same reading frame as the EcoRI site in the beta-galactosidase gene of lambda gt11 and termination codons occurred downstream in all three reading frames. A clone was selected from a gt11 library based on the production of a protein that reacted with antibodies to flagellin from Campylobacter jejuni. DNA from this clone was digested with EcoRI, the insert fragment purified and ligated into the EcoRI site of pBEB. A fusion protein of 43 kDa was produced that reacted in Western blot with antibodies against LT-B and flagellin. We have succeeded in making an easy method for subcloning fragments from gt11 into a vector for making LT-B fusion proteins.

  20. Site-specific modification of genome with cell-permeable Cre fusion protein in preimplantation mouse embryo

    International Nuclear Information System (INIS)

    Kim, Kyoungmi; Kim, Hwain; Lee, Daekee

    2009-01-01

    Site-specific recombination (SSR) by Cre recombinase and its target sequence, loxP, is a valuable tool in genetic analysis of gene function. Recently, several studies reported successful application of Cre fusion protein containing protein transduction peptide for inducing gene modification in various mammalian cells including ES cell as well as in the whole animal. In this study, we show that a short incubation of preimplantation mouse embryos with purified cell-permeable Cre fusion protein results in efficient SSR. X-Gal staining of preimplantation embryos, heterozygous for Gtrosa26 tm1Sor , revealed that treatment of 1-cell or 2-cell embryos with 3 μM of Cre fusion protein for 2 h leads to Cre-mediated excision in 70-85% of embryos. We have examined the effect of the concentration of the Cre fusion protein and the duration of the treatment on embryonic development, established a condition for full term development and survival to adulthood, and demonstrated the germ line transmission of excised Gtrosa26 allele. Potential applications and advantages of the highly efficient technique described here are discussed.

  1. Residues in the hendra virus fusion protein transmembrane domain are critical for endocytic recycling.

    Science.gov (United States)

    Popa, Andreea; Carter, James R; Smith, Stacy E; Hellman, Lance; Fried, Michael G; Dutch, Rebecca Ellis

    2012-03-01

    Hendra virus is a highly pathogenic paramyxovirus classified as a biosafety level four agent. The fusion (F) protein of Hendra virus is critical for promoting viral entry and cell-to-cell fusion. To be fusogenically active, Hendra virus F must undergo endocytic recycling and cleavage by the endosomal/lysosomal protease cathepsin L, but the route of Hendra virus F following internalization and the recycling signals involved are poorly understood. We examined the intracellular distribution of Hendra virus F following endocytosis and showed that it is primarily present in Rab5- and Rab4-positive endosomal compartments, suggesting that cathepsin L cleavage occurs in early endosomes. Hendra virus F transmembrane domain (TMD) residues S490 and Y498 were found to be important for correct Hendra virus F recycling, with the hydroxyl group of S490 and the aromatic ring of Y498 important for this process. In addition, changes in association of isolated Hendra virus F TMDs correlated with alterations to Hendra virus F recycling, suggesting that appropriate TMD interactions play an important role in endocytic trafficking.

  2. NUP98 Fusion Proteins Interact with the NSL and MLL1 Complexes to Drive Leukemogenesis.

    Science.gov (United States)

    Xu, Haiming; Valerio, Daria G; Eisold, Meghan E; Sinha, Amit; Koche, Richard P; Hu, Wenhuo; Chen, Chun-Wei; Chu, S Haihua; Brien, Gerard L; Park, Christopher Y; Hsieh, James J; Ernst, Patricia; Armstrong, Scott A

    2016-12-12

    The nucleoporin 98 gene (NUP98) is fused to a variety of partner genes in multiple hematopoietic malignancies. Here, we demonstrate that NUP98 fusion proteins, including NUP98-HOXA9 (NHA9), NUP98-HOXD13 (NHD13), NUP98-NSD1, NUP98-PHF23, and NUP98-TOP1 physically interact with mixed lineage leukemia 1 (MLL1) and the non-specific lethal (NSL) histone-modifying complexes. Chromatin immunoprecipitation sequencing illustrates that NHA9 and MLL1 co-localize on chromatin and are found associated with Hox gene promoter regions. Furthermore, MLL1 is required for the proliferation of NHA9 cells in vitro and in vivo. Inactivation of MLL1 leads to decreased expression of genes bound by NHA9 and MLL1 and reverses a gene expression signature found in NUP98-rearranged human leukemias. Our data reveal a molecular dependency on MLL1 function in NUP98-fusion-driven leukemogenesis. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Protective effects of protein transduction domain-metallothionein fusion proteins against hypoxia- and oxidative stress-induced apoptosis in an ischemia/reperfusion rat model.

    Science.gov (United States)

    Lim, Kwang Suk; Cha, Min-Ji; Kim, Jang Kyoung; Park, Eun Jeong; Chae, Ji-Won; Rhim, Taiyoun; Hwang, Ki-Chul; Kim, Yong-Hee

    2013-08-10

    Ischemic heart diseases caused by insufficient oxygen supply to the cardiac muscle require pharmaceutical agents for the prevention of the progress and recurrence. Metallothionein (MT) has a potential as a protein therapeutic for the treatment of this disease due to its anti-oxidative effects under stressful conditions. In spite of its therapeutic potential, efficient delivery systems need to be developed to overcome limitations such as low transduction efficiency, instability and short half-life in the body. To enhance intra-cellular transduction efficiency, Tat sequence as a protein transduction domain (PTD) was fused with MT in a recombinant method. Anti-apoptotic and anti-oxidative effects of Tat-MT fusion protein were evaluated under hyperglycemia and hypoxia stress conditions in cultured H9c2 cells. Recovery of cardiac functions by anti-apoptotic and anti-fibrotic effects of Tat-MT was confirmed in an ischemia/reperfusion (I/R) rat myocardial infarction model. Tat-MT fusion protein effectively protected H9c2 cells under stressful conditions by reducing intracellular ROS production and inhibiting caspase-3 activation. Tat-MT fusion protein inhibited apoptosis, reduced fibrosis area and enhanced cardiac functions in I/R. Tat-MT fusion protein could be a promising therapeutic for the treatment of ischemic heart diseases. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Analysis of the selective advantage conferred by a C-E1 fusion protein synthesized by rubella virus DI RNAs

    International Nuclear Information System (INIS)

    Claus, Claudia; Tzeng, W.-P.; Liebert, Uwe Gerd; Frey, Teryl K.

    2007-01-01

    During serial passaging of rubella virus (RUB) in cell culture, the dominant species of defective-interfering RNA (DI) generated contains an in-frame deletion between the capsid protein (C) gene and E1 glycoprotein gene resulting in production of a C-E1 fusion protein that is necessary for the maintenance of the DI [Tzeng, W.P., Frey, T.K. (2006). C-E1 fusion protein synthesized by rubella virus DI RNAs maintained during serial passage. Virology 356 198-207.]. A BHK cell line stably expressing the RUB structural proteins was established which was used to package DIs into virus particles following transfection with in vitro transcripts from DI infectious cDNA constructs. Packaging of a DI encoding an in-frame C-GFP-E1 reporter fusion protein corresponding to the C-E1 fusion protein expressed in a native DI was only marginally more efficient than packaging of a DI encoding GFP, indicating that the C-E1 fusion protein did not function by enhancing packaging. However, infection with the DI encoding the C-GFP-E1 fusion protein (in the absence of wt RUB helper virus) resulted in formation of clusters of GFP-positive cells and the percentage of GFP-positive cells in the culture following infection remained relatively constant. In contrast, a DI encoding GFP did not form GFP-positive clusters and the percentage of GFP-positive cells declined by roughly half from 2 to 4 days post-infection. Cluster formation and sustaining the percentage of infected (GFP-positive) cells required the C part of the fusion protein, including the downstream but not the upstream of two arginine clusters (both of which are associated with RNA binding and association with mitochondrial p32 protein) and the E1 part through the transmembrane sequence, but not the C-terminal cytoplasmic tail. Among a collection of mutant DI constructs, cluster formation and sustaining infected cell percentage correlated with maintenance during serial passage with wt RUB. We hypothesize that cluster formation and

  5. Intracellular delivery of cell-penetrating peptide-transcriptional factor fusion protein and its role in selective osteogenesis

    Directory of Open Access Journals (Sweden)

    Suh JS

    2014-03-01

    Full Text Available Jin Sook Suh,1,* Jue Yeon Lee,2,* Yoon Jung Choi,1 Hyung Keun You,3 Seong-Doo Hong,4 Chong Pyoung Chung,2 Yoon Jeong Park1,2 1Dental Regenerative Biotechnology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, 2Central Research Institute, Nano Intelligent Biomedical Engineering Corporation (NIBEC, Seoul, 3Department of Periodontology, College of Dentistry, Wonkwang University, Iksan, 4Department of Oral Pathology, School of Dentistry, Seoul National University, Seoul, Republic of Korea *These authors contributed equally to this work Abstract: Protein-transduction technology has been attempted to deliver macromolecular materials, including protein, nucleic acids, and polymeric drugs, for either diagnosis or therapeutic purposes. Herein, fusion protein composed of an arginine-rich cell-penetrating peptide, termed low-molecular-weight protamine (LMWP, and a transcriptional coactivator with a PDZ-binding motif (TAZ protein was prepared and applied in combination with biomaterials to increase bone-forming capacity. TAZ has been recently identified as a specific osteogenic stimulating transcriptional coactivator in human mesenchymal stem cell (hMSC differentiation, while simultaneously blocking adipogenic differentiation. However, TAZ by itself cannot penetrate the cells, and thus needs a transfection tool for translocalization. The LMWP-TAZ fusion proteins were efficiently translocalized into the cytosol of hMSCs. The hMSCs treated with cell-penetrating LMWP-TAZ exhibited increased expression of osteoblastic genes and protein, producing significantly higher quantities of mineralized matrix compared to free TAZ. In contrast, adipogenic differentiation of the hMSCs was blocked by treatment of LMWP-TAZ fusion protein, as reflected by reduced marker-protein expression, adipocyte fatty acid-binding protein 2, and peroxisome proliferator-activated receptor-γ messenger ribonucleic acid levels. LMWP-TAZ was applied in

  6. A fusion protein of interleukin-4 and interleukin-10 protects against blood-induced cartilage damage in vitro and in vivo

    NARCIS (Netherlands)

    van Vulpen, L F D; Popov-Celeketic, J; van Meegeren, M. E R; Coeleveld, K; van Laar, J M; Hack, C E; Schutgens, R E G; Mastbergen, S C; Lafeber, F P J G

    Essentials Targeted treatment for hemophilic arthropathy, still causing significant morbidity, is lacking. This study evaluates the efficacy of a fusion of protein of interleukin(IL)-4 and IL-10. In vitro the fusion protein prevents blood-induced cartilage damage in a dose-dependent manner. In

  7. Oncogenic fusion proteins expressed in immature hematopoietic cells fail to recapitulate the transcriptional changes observed in human AML

    DEFF Research Database (Denmark)

    Rapin, N; Porse, B T

    2014-01-01

    Reciprocal chromosomal translocations are observed in one-third of acute myeloid leukemia (AML) cases. Targeting and understanding the effects of the resulting aberrant oncogenic fusion proteins may help developing drugs against specific leukemic subtypes, as demonstrated earlier by the use of ATRA....... Surprisingly, we found that the gene-expression profiles of CD34+ human HSPCs transformed with the potent oncogenic fusion proteins AML-ETO or MLL-AF9, only weakly resembled those derived from primary AML samples. Hence, our work raises concerns as to the relevance of the use of in vitro transduced cells...... in acute promyelocytic leukemia. Hematopoietic stem/progenitor (HSPCs) cells transduced with oncogenic fusion genes are regarded as promising in vitromodels of their corresponding AML subtypes. Here, we critically assessed the potential of such in vitro models using an integrative bioinformatics approach...

  8. [Rapid expression and preparation of the recombinant fusion protein sTNFRII-gAD by adenovirus vector system].

    Science.gov (United States)

    Lu, Yue; Liu, Dan; Zhang, Xiaoren; Liu, Xuerong; Shen, Wei; Zheng, Gang; Liu, Yunfan; Dong, Xiaoyan; Wu, Xiaobing; Gao, Jimin

    2011-08-01

    We expressed and prepared the recombinant fusion protein sTNFRII-gAD consisted of soluble TNF receptor II and the globular domain of adiponectin by Adenovirus Vector System in mammalian BHK21c022 cells. First we used the adenovirus vector containing EGFP gene (rAd5-EGFP) to infect BHK21c022 cells at different MOI (from 0 to 1 000), and then evaluated their transduction efficiency and cytotoxicity. Similarly, we constructed the replication-deficient adenovirus type 5-sTNFRII-gAD (rAd5-sTNFRII-gAD). We collected the supernatants for Western blotting to determine the optimal MOI by comparing the expression levels of sTNFRII-gAD fusion protein, 48 h after the BHK21c022 cells were infected by rAd5-sTNFRII-gAD at different MOIs (from 0 to 1 000). Then, we chose rAd5-sTNFRII-gAD at MOI 100 to infect five bottles of BHK21c022 cells in 100 mL of serum-free chemically defined media 100 mL, harvested the supernatant every 48 h for 6 times, and condense and purify sTNFRII-gAD fusion protein by ammonium sulfate salt-out and size-exclusion chromatography, respectively. Finally, we analyzed anti-TNFalpha activity of sTNFRII-gAD fusion protein on L929 cells in vitro. The results showed that the number of BHK21c022 cells expressing EGFP protein was increased significantly with the increase of MOI. However, some cells died at MOI of 1 000 while there was no significant cytotoxicity at MOI from 0 to 100. Western blotting analysis showed that the more adenoviruses, the higher expression of sTNFRII-gAD fusion protein in the supernatant with the highest expression at MOI 1 000. We successfully obtained about 11 mg bioactive and purified sTNFRII-gAD fusion protein at last. The in vitro assay demonstrated that the sTNFRII-gAD fusion protein was potent to antagonize TNFalpha's cytotoxicity to L929 cells. Put together, we established a recombinant adenovirus vector/BHK21 cell expression system, characteristic of the efficient serum-free culture and easy scaling-up.

  9. Mimivirus reveals Mre11/Rad50 fusion proteins with a sporadic distribution in eukaryotes, bacteria, viruses and plasmids.

    Science.gov (United States)

    Yoshida, Takashi; Claverie, Jean-Michel; Ogata, Hiroyuki

    2011-09-07

    The Mre11/Rad50 complex and the homologous SbcD/SbcC complex in bacteria play crucial roles in the metabolism of DNA double-strand breaks, including DNA repair, genome replication, homologous recombination and non-homologous end-joining in cellular life forms and viruses. Here we investigated the amino acid sequence of the Mimivirus R555 gene product, originally annotated as a Rad50 homolog, and later shown to have close homologs in marine microbial metagenomes. Our bioinformatics analysis revealed that R555 protein sequence is constituted from the fusion of an N-terminal Mre11-like domain with a C-terminal Rad50-like domain. A systematic database search revealed twelve additional cases of Mre11/Rad50 (or SbcD/SbcC) fusions in a wide variety of unrelated organisms including unicellular and multicellular eukaryotes, the megaplasmid of a bacterium associated to deep-sea hydrothermal vents (Deferribacter desulfuricans) and the plasmid of Clostridium kluyveri. We also showed that R555 homologs are abundant in the metagenomes from different aquatic environments and that they most likely belong to aquatic viruses. The observed phyletic distribution of these fusion proteins suggests their recurrent creation and lateral gene transfers across organisms. The existence of the fused version of protein sequences is consistent with known functional interactions between Mre11 and Rad50, and the gene fusion probably enhanced the opportunity for lateral transfer. The abundance of the Mre11/Rad50 fusion genes in viral metagenomes and their sporadic phyletic distribution in cellular organisms suggest that viruses, plasmids and transposons played a crucial role in the formation of the fusion proteins and their propagation into cellular genomes.

  10. Mimivirus reveals Mre11/Rad50 fusion proteins with a sporadic distribution in eukaryotes, bacteria, viruses and plasmids

    Directory of Open Access Journals (Sweden)

    Ogata Hiroyuki

    2011-09-01

    Full Text Available Abstract Background The Mre11/Rad50 complex and the homologous SbcD/SbcC complex in bacteria play crucial roles in the metabolism of DNA double-strand breaks, including DNA repair, genome replication, homologous recombination and non-homologous end-joining in cellular life forms and viruses. Here we investigated the amino acid sequence of the Mimivirus R555 gene product, originally annotated as a Rad50 homolog, and later shown to have close homologs in marine microbial metagenomes. Results Our bioinformatics analysis revealed that R555 protein sequence is constituted from the fusion of an N-terminal Mre11-like domain with a C-terminal Rad50-like domain. A systematic database search revealed twelve additional cases of Mre11/Rad50 (or SbcD/SbcC fusions in a wide variety of unrelated organisms including unicellular and multicellular eukaryotes, the megaplasmid of a bacterium associated to deep-sea hydrothermal vents (Deferribacter desulfuricans and the plasmid of Clostridium kluyveri. We also showed that R555 homologs are abundant in the metagenomes from different aquatic environments and that they most likely belong to aquatic viruses. The observed phyletic distribution of these fusion proteins suggests their recurrent creation and lateral gene transfers across organisms. Conclusions The existence of the fused version of protein sequences is consistent with known functional interactions between Mre11 and Rad50, and the gene fusion probably enhanced the opportunity for lateral transfer. The abundance of the Mre11/Rad50 fusion genes in viral metagenomes and their sporadic phyletic distribution in cellular organisms suggest that viruses, plasmids and transposons played a crucial role in the formation of the fusion proteins and their propagation into cellular genomes.

  11. Characterization of an immunomodulatory Der p 2-FIP-fve fusion protein produced in transformed rice suspension cell culture.

    Science.gov (United States)

    Su, Chin-Fen; Kuo, I-Chun; Chen, Peng-Wen; Huang, Chiung-Hui; Seow, See Voon; Chua, Kaw Yan; Yu, Su-May

    2012-02-01

    Der p 2, a major allergen of Dermatophagoides pteronyssinus mites, is one of the most clinically relevant allergens to allergic patients worldwide. FIP-fve protein (Fve) from the golden needle mushroom (Flammulina velutipes) is an immunomodulatory protein with potential Th1-skewed adjuvant properties. Here, we produced and immunologically evaluated a Der p 2-Fve fusion protein as a potential immunotherapeutic for allergic diseases. Using an inducible expression system in cultured rice suspension cells, the recombinant Der p 2-Fve fusion protein (designated as OsDp2Fve) was expressed in rice cells under the control of an α-amylase gene (αAmy8) promoter and secreted under sucrose starvation. OsDp2Fve was partially purified from the cultured medium. The conformation of Der p 2 in OsDp2Fve remains intact as reflected by its unaltered allergenicity, as assessed by human IgE ELISA and histamine release assays, compared to non-fusion Der p 2 protein. Furthermore, the Fve protein expressed in OsDp2Fve retains its in vitro lymphoproliferative activity but loses its hemagglutination and lymphoagglutination effects compared to the native protein. Notably, in vivo evaluation showed that mice administered with OsDp2Fve possessed an enhanced production of Der p 2-specific IgG antibodies without potentiating the production of Der p 2-specific IgE and Th2 effector cytokines in comparison with mice co-administered with native Fve and Der p 2 proteins. These results suggest that the recombinant Der p 2-Fve fusion protein produced in rice suspension cell cultures has a great potential for allergy immunotherapy.

  12. Production of N-acetyl-D-neuraminic acid using two sequential enzymes overexpressed as double-tagged fusion proteins

    Directory of Open Access Journals (Sweden)

    Cheng Chung-Hsien

    2009-07-01

    Full Text Available Abstract Background Two sequential enzymes in the production of sialic acids, N-acetyl-D-glucosamine 2-epimerase (GlcNAc 2-epimerase and N-acetyl-D-neuraminic acid aldolase (Neu5Ac aldolase, were overexpressed as double-tagged gene fusions. Both were tagged with glutathione S-transferase (GST at the N-terminus, but at the C-terminus, one was tagged with five contiguous aspartate residues (5D, and the other with five contiguous arginine residues (5R. Results Both fusion proteins were overexpressed in Escherichia coli and retained enzymatic activity. The fusions were designed so their surfaces were charged under enzyme reaction conditions, which allowed isolation and immobilization in a single step, through a simple capture with either an anionic or a cationic exchanger (Sepharose Q or Sepharose SP that electrostatically bound the 5D or 5R tag. The introduction of double tags only marginally altered the affinity of the enzymes for their substrates, and the double-tagged proteins were enzymatically active in both soluble and immobilized forms. Combined use of the fusion proteins led to the production of N-acetyl-D-neuraminic acid (Neu5Ac from N-acetyl-D-glucosamine (GlcNAc. Conclusion Double-tagged gene fusions were overexpressed to yield two enzymes that perform sequential steps in sialic acid synthesis. The proteins were easily immobilized via ionic tags onto ionic exchange resins and could thus be purified by direct capture from crude protein extracts. The immobilized, double-tagged proteins were effective for one-pot enzymatic production of sialic acid.

  13. Production and evaluation of cytotoxic effects of DT386-BR2 fusion protein as a novel anti-cancer agent.

    Science.gov (United States)

    Shafiee, Fatemeh; Rabbani, Mohammad; Jahanian-Najafabadi, Ali

    2016-11-01

    The aim of this study was to produce a fusion protein consisting of the catalytic and translocation domains of diphtheria toxin fused to BR2, a cancer specific cell penetrating peptide, and evaluation of its cytotoxic effects for targeted eradication of cancer cells. For this purpose, The DT386-BR2 structure was predicted using Modeller 9.14 and the best predicted model was selected based on the minimum DOPE score. A synthetic gene encoding DT386-BR2 was cloned in pET28a expression vector, expressed and purified by affinity chromatography. SDS-PAGE and Western blotting confirmed the expression of the DT386-BR2 fusion protein by revealing a band of about 47kDa after the induction of the expression. Finally, the purified protein was subjected to MTT assay for evaluation of its cyto-lethal effects on cancer and normal cell lines. Statistical analysis showed significant reduction in survival percent of HeLa and MCF-7 cancer cells in comparison to negative control (PBS), while the cytotoxic effect was not significant on the normal cells, i.e. HUVEC and HEK 293. The IC50 of DT386-BR2 for HeLa and MCF-7 was about 0.55 and 2.08μg/ml, respectively. In conclusion, the production and purification of DT386-BR2 fusion protein was successfully achieved and its cytotoxic effects on the studied cancer cell lines was established. The promising cytotoxic effects of this newly constructed fusion protein made it a suitable candidate for targeted therapy of cancer, and further in vitro and in vivo studies on this fusion protein is underway. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Biophysical evaluation of hybrid Fc fusion protein of hGH to achieve basal buffer system.

    Science.gov (United States)

    Kim, Nam Ah; An, In Bok; Lim, Hye Seong; Yang, Sang In; Jeong, Seong Hoon

    2016-11-20

    A newly developed hybrid Fc (hyFc) is a non-immunogenic and non-cytolytic Fc with intact Ig structure derived from human IgD and IgG4. It is fused with the human growth hormone (GXD-9) and was evaluated by various biophysical techniques. Two thermal transitions were evident by DSC, reflecting the unfolding of IgG4 and the conjugated protein. The highest T m of the initial GXD-9 was 68.17°C and the T m of the two domains were around 66°C and 70°C. Although T m increased with decreasing concentration, which reflects increasing conformational stability, aggregation issues were still observed by DLS. This might be caused by decreasing or low zeta potential due to a highly complex structure. The protein was dialyzed to various pH (6.2-8.2) values to enhance conformational stability and to overcome aggregation issues. The results of CD spectroscopy were correlated with DSC measurements to evaluate its conformational stability. Changes in secondary structural contents were similar as determined by DSC and DLS. In conclusion, GXD-9 was found to be most stable at pH 7.0. The investigation of the biophysical stability of a hyFc-fusion protein has demonstrated a positive feasibility of developing more stable formulations to facilitate the initial drug development process for further clinical trials. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Constitutively active IRF7/IRF3 fusion protein completely protects swine against Foot-and-Mouth Disease

    Science.gov (United States)

    Foot-and-mouth disease (FMD) remains one of the most devastating livestock diseases around the world. Several serotype specific vaccine formulations exist but require about 5-7 days to induce protective immunity. Our previous studies have shown that a constitutively active fusion protein of porcine ...

  16. Evaluation of a lysostaphin-fusion protein as a dry-cow therapy for Staphylococcus aureus mastitis in dairy cattle

    Science.gov (United States)

    This study evaluated the efficacy of a lysostaphin-fusion protein (Lyso-PTD) as a dry-cow therapy for the treatment of experimentally-induced chronic, subclinical Staphylococcus aureus mastitis. Twenty-two Holstein dairy cows were experimentally infected with Staph. aureus in a single pair of diago...

  17. Coating Nanoparticles with Plant-Produced Transferrin-Hydrophobin Fusion Protein Enhances Their Uptake in Cancer Cells

    DEFF Research Database (Denmark)

    Reuter, Lauri J.; Shahbazi, Mohammad-Ali; Makila, Ermei M.

    2017-01-01

    The encapsulation of drugs to nanoparticles may offer a solution for targeted delivery. Here, we set out to engineer a self assembling targeting ligand by combining the functional properties of human transferrin and fungal hydrophobins in a single fusion protein. We showed that human transferrin...

  18. Assessment of the Fusion Tags on Increasing Soluble Production of the Active TEV Protease Variant and Other Target Proteins in E. coli.

    Science.gov (United States)

    Yu, Xuelian; Sun, Jiaqi; Wang, Weiyu; Jiang, Li; Cheng, Beijiu; Fan, Jun

    2017-06-01

    In this study, five fusion tags affecting soluble production and cleavage activity of the tobacco etch virus (TEV) protease (TEVp) variant in Escherichia coli strains BL21 (DE3) and Rosetta™ (DE3) are investigated. Combination of the augmenting rare transfer RNAs (tRNAs) and the fused expressivity tag (N-terminal seven amino acid residues of E. coli translation initiation factor II) promotes the soluble TEVp partner expressed at relatively high level. Attachment of the maltose-binding protein (MBP) tag increases soluble expression of the protease released from the fusion protein in E. coli cells, but the incorporated TEVp recognition sequence slightly decreases expressivity of the fusion construct. Except for the green fluorescent protein, the attached expressivity tag shows less efficiency than the MBP tag in enhancing expression levels of the selected five target proteins in the Rosetta™ (DE3) cells under different induction conditions. Our results identified that high-level production of the functional target protein as the fusion partner in E. coli is combined with the intrinsic property of fusion tag, fusion protein stability, inherent folding of target protein, rare tRNA abundance, and the incorporated linker. Purified TEVp fusion constructs with the N-terminal expressivity tag, as well as the MBP partner, are the ideal alternatives for removing fusion tag.

  19. The mesodermal expression of rolling stone (rost) is essential for myoblast fusion in Drosophila and encodes a potential transmembrane protein.

    Science.gov (United States)

    Paululat, A; Goubeaud, A; Damm, C; Knirr, S; Burchard, S; Renkawitz-Pohl, R

    1997-07-28

    In homozygous rolling stone embryos, the fusion of myoblasts to syncytial myotubes is diminished. Nevertheless, the visceral mesoderm, the heart mesoderm, and few somatic muscles are properly formed. Thus, we postulate a central role of rolling stone for the fusion process within the somatic mesoderm. We have cloned the rolling stone gene, and the deduced protein sequence is in accordance with a transmembrane protein, which agrees with the enrichment of Rost in the membrane fraction of Drosophila embryos. No homologous genes have been described so far. rolling stone is expressed in the embryonic nervous system and cells of the somatic mesoderm, most notable in muscle founder cells. To elucidate the function of rolling stone for myoblast fusion, we applied a knock-out strategy. The expression of an antisense rolling stone transcript specifically within the mesoderm of wild-type embryos results in fusion defects of myoblasts, proving that the rolling stone expression in the mesoderm is responsible for the rolling stone phenotype. We suggest that rolling stone is a member of a group of genes that are necessary for the fusion process during myogenesis.

  20. pH regulation in early endosomes and interferon-inducible transmembrane proteins control avian retrovirus fusion.

    Science.gov (United States)

    Desai, Tanay M; Marin, Mariana; Mason, Caleb; Melikyan, Gregory B

    2017-05-12

    Enveloped viruses infect host cells by fusing their membranes with those of the host cell, a process mediated by viral glycoproteins upon binding to cognate host receptors or entering into acidic intracellular compartments. Whereas the effect of receptor density on viral infection has been well studied, the role of cell type-specific factors/processes, such as pH regulation, has not been characterized in sufficient detail. Here, we examined the effects of cell-extrinsic factors (buffer environment) and cell-intrinsic factors (interferon-inducible transmembrane proteins, IFITMs), on the pH regulation in early endosomes and on the efficiency of acid-dependent fusion of the avian sarcoma and leukosis virus (ASLV), with endosomes. First, we found that a modest elevation of external pH can raise the pH in early endosomes in a cell type-dependent manner and thereby delay the acid-induced fusion of endocytosed ASLV. Second, we observed a cell type-dependent delay between the low pH-dependent and temperature-dependent steps of viral fusion, consistent with the delayed enlargement of the fusion pore. Third, ectopic expression of IFITMs, known to potently block influenza virus fusion with late compartments, was found to only partially inhibit ASLV fusion with early endosomes. Interestingly, IFITM expression promoted virus uptake and the acidification of endosomal compartments, resulting in an accelerated fusion rate when driven by the glycosylphosphatidylinositol-anchored, but not by the transmembrane isoform of the ASLV receptor. Collectively, these results highlight the role of cell-extrinsic and cell-intrinsic factors in regulating the efficiency and kinetics of virus entry and fusion with target cells. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Generation of a selectively cytotoxic fusion protein against p53 mutated cancers

    Directory of Open Access Journals (Sweden)

    Kousparou Christina A

    2012-08-01

    Full Text Available Abstract Background A significant number of cancers are caused by defects in p21 causing functional defects in p21 or p53 tumour-suppressor proteins. This has led to many therapeutic approaches including restoration by gene therapy with wild-type p53 or p21 using viral or liposomal vectors, which have toxicity or side-effect limitations. We set out to develop a safer, novel fusion protein which has the ability to reconstitute cancer cell lines with active p21 by protein transduction. Methods The fusion protein was produced from the cell-translocating peptide Antennapedia (Antp and wild-type, full-length p21 (Antp-p21. This was expressed and refolded from E. coli and tested on a variety of cell lines and tumours (in a BALB/c nude xenograft model with differing p21 or p53 status. Results Antp-p21 penetrated and killed cancer cells that do not express wild type p53 or p21. This included cells that were matched to cogenic parental cell lines. Antp-p21 killed cancer cells selectively that were malignant as a result of mutations or nuclear exclusion of the p53 and p21 genes and over-expression of MDM2. Non-specific toxicity was excluded by showing that Antp-p21 penetrated but did not kill p53- or p21- wild-type cells. Antp-p21 was not immunogenic in normal New Zealand White rabbits. Recombinant Antp peptide alone was not cytotoxic, showing that killing was due to the transduction of the p21 component of Antp-p21. Antp-p21 was shown to penetrate cancer cells engrafted in vivo and resulted in tumour eradication when administered with conventionally-used chemotherapeutic agents, which alone were unable to produce such an effect. Conclusions Antp-p21 may represent a new and promising targeted therapy for patients with p53-associated cancers supporting the concept that rational design of therapies directed against specific cancer mutations will play a part in the future of medical oncology.

  2. Generation of a selectively cytotoxic fusion protein against p53 mutated cancers

    International Nuclear Information System (INIS)

    Kousparou, Christina A; Yiacoumi, Efthymia; Deonarain, Mahendra P; Epenetos, Agamemnon A

    2012-01-01

    A significant number of cancers are caused by defects in p21 causing functional defects in p21 or p53 tumour-suppressor proteins. This has led to many therapeutic approaches including restoration by gene therapy with wild-type p53 or p21 using viral or liposomal vectors, which have toxicity or side-effect limitations. We set out to develop a safer, novel fusion protein which has the ability to reconstitute cancer cell lines with active p21 by protein transduction. The fusion protein was produced from the cell-translocating peptide Antennapedia (Antp) and wild-type, full-length p21 (Antp-p21). This was expressed and refolded from E. coli and tested on a variety of cell lines and tumours (in a BALB/c nude xenograft model) with differing p21 or p53 status. Antp-p21 penetrated and killed cancer cells that do not express wild type p53 or p21. This included cells that were matched to cogenic parental cell lines. Antp-p21 killed cancer cells selectively that were malignant as a result of mutations or nuclear exclusion of the p53 and p21 genes and over-expression of MDM2. Non-specific toxicity was excluded by showing that Antp-p21 penetrated but did not kill p53- or p21- wild-type cells. Antp-p21 was not immunogenic in normal New Zealand White rabbits. Recombinant Antp peptide alone was not cytotoxic, showing that killing was due to the transduction of the p21 component of Antp-p21. Antp-p21 was shown to penetrate cancer cells engrafted in vivo and resulted in tumour eradication when administered with conventionally-used chemotherapeutic agents, which alone were unable to produce such an effect. Antp-p21 may represent a new and promising targeted therapy for patients with p53-associated cancers supporting the concept that rational design of therapies directed against specific cancer mutations will play a part in the future of medical oncology

  3. Chimeric Bovine Respiratory Syncytial Virus with Attachment and Fusion Glycoproteins Replaced by Bovine Parainfluenza Virus Type 3 Hemagglutinin-Neuraminidase and Fusion Proteins

    Science.gov (United States)

    Stope, Matthias B.; Karger, Axel; Schmidt, Ulrike; Buchholz, Ursula J.

    2001-01-01

    Chimeric bovine respiratory syncytial viruses (BRSV) expressing glycoproteins of bovine parainfluenza virus type 3 (BPIV-3) instead of BRSV glycoproteins were generated from cDNA. In the BRSV antigenome cDNA, the open reading frames of the major BRSV glycoproteins, attachment protein G and fusion protein F, were replaced individually or together by those of the BPIV-3 hemagglutinin-neuraminidase (HN) and/or fusion (F) glycoproteins. Recombinant virus could not be recovered from cDNA when the BRSV F open reading frame was replaced by the BPIV-3 F open reading frame. However, cDNA recovery of the chimeric virus rBRSV-HNF, with both glycoproteins replaced simultaneously, and of the chimeric virus rBRSV-HN, with the BRSV G protein replaced by BPIV-3 HN, was successful. The replication rates of both chimeras were similar to that of standard rBRSV. Moreover, rBRSV-HNF was neutralized by antibodies specific for BPIV-3, but not by antibodies specific to BRSV, demonstrating that the BRSV glycoproteins can be functionally replaced by BPIV-3 glycoproteins. In contrast, rBRSV-HN was neutralized by BRSV-specific antisera, but not by BPIV-3 specific sera, showing that infection of rBRSV-HN is mediated by BRSV F. Hemadsorption of cells infected with rBRSV-HNF and rBRSV-HN proved that BPIV-3 HN protein expressed by rBRSV is functional. Colocalization of the BPIV-3 glycoproteins with BRSV M protein was demonstrated by confocal laser scan microscopy. Moreover, protein analysis revealed that the BPIV-3 glycoproteins were present in chimeric virions. Taken together, these data indicate that the heterologous glycoproteins were not only expressed but were incorporated into the envelope of recombinant BRSV. Thus, the envelope glycoproteins derived from a member of the Respirovirus genus can together functionally replace their homologs in a Pneumovirus background. PMID:11533200

  4. Generation of New M2e-HA2 Fusion Chimeric Peptide to Development of a Recombinant Fusion Protein Vaccine

    OpenAIRE

    Ameghi, Ali; Baradaran, Behzad; Aghaiypour, Khosrow; Barzegar, Abolfazl; Pilehvar-Soltanahmadi, Yones; Moghadampour, Masood; Taghizadeh, Morteza; Zarghami, Nosratollah

    2015-01-01

    Purpose: The purpose was to design a new construction containing influenza virus (H1N1) M2e gene and HA2 gene by bioinformatics approach, cloning the construct in to Escherichia coli and produce M2e-HA2 peptide. Methods: The procedure was done by virus cultivation in SPF eggs, hemagglutination assay (HA), RNA isolation, RT-PCR, primers designed (DNAMAN 4 and Oligo7), virtual fusion construction translation (ExPASy), N-Glycosylated sites prediction (Ensemblegly-Iowa), c...

  5. [Prokaryotic expression, purification and identification of NY-ESO-1/GST fusion protein in E.coli].

    Science.gov (United States)

    Tang, Lei; Song, Chao-jun; Sun, Yuan-jie; Li, Na; Wei, Yu-ying; Sun, Yi; Yang, Kun

    2012-10-01

    To construct an expression plasmid for NY-ESO-1 gene and identify the expression of recombinant protein NY-ESO-1/GST in E.coli. NY-ESO-1 segment was amplified from the testis cDNA library by RT-PCR and cloned into the prokaryotic expression vector pGEX4T-1 downstream tagged by GST to construct the expression plasmid pGEX-4T1-NY-ESO-1. The recombinant vector was transformed to BL21 (DE3) and NY-ESO-1/GST fusion protein was induced expression by IPTG. The protein was purified by urea elution and identified by SDS-PAGE and Western blotting. The NY-ESO-1 segment was successfully amplified and its sequence was identical with that published in GenBank. The BL21 (DE3) pLysS containing the pGEX-4T1-NY-ESO-1 expressed a M(r); 44 000 fusion protein under the induction of IPTG. The purity of the protein was 90%. Western blotting proved that NY-ESO-1/GST had a specific reaction with anti-GST mAb. The prokaryotic expression vector of NY-ESO-1 has been constructed and the fusion protein NY-ESO-1/GST of high purity is successfully expressed.

  6. Molecular dynamics analysis of conformational change of paramyxovirus F protein during the initial steps of membrane fusion

    International Nuclear Information System (INIS)

    Martín-García, Fernando; Mendieta-Moreno, Jesús Ignacio; Mendieta, Jesús; Gómez-Puertas, Paulino

    2012-01-01

    Highlights: ► Initial conformational change of paramyxovirus F protein is caused only by mechanical forces. ► HRA region undergoes a structural change from a beta + alpha conformation to an extended coil and then to an all-alpha conformation. ► HRS domains of F protein form three single α-helices prior to generation of the coiled coil. -- Abstract: The fusion of paramyxovirus to the cell membrane is mediated by fusion protein (F protein) present in the virus envelope, which undergoes a dramatic conformational change during the process. Unlike hemagglutinin in orthomyxovirus, this change is not mediated by an alteration of environmental pH, and its cause remains unknown. Steered molecular dynamics analysis leads us to suggest that the conformational modification is mediated only by stretching mechanical forces once the transmembrane fusion peptide of the protein is anchored to the cell membrane. Such elongating forces will generate major secondary structure rearrangement in the heptad repeat A region of the F protein; from β-sheet conformation to an elongated coil and then spontaneously to an α-helix. In addition, it is proposed that the heptad repeat A region adopts a final three-helix coiled coil and that this structure appears after the formation of individual helices in each monomer.

  7. Role of conserved histidine residues in the low-pH dependence of the Semliki Forest virus fusion protein.

    Science.gov (United States)

    Qin, Zhao-Ling; Zheng, Yan; Kielian, Margaret

    2009-05-01

    A wide variety of enveloped viruses infects cells by taking advantage of the low pH in the endocytic pathway to trigger virus-membrane fusion. For alphaviruses such as Semliki Forest virus (SFV), acidic pH initiates a series of conformational changes in the heterodimeric virus envelope proteins E1 and E2. Low pH dissociates the E2/E1 dimer, releasing the membrane fusion protein E1. E1 inserts into the target membrane and refolds to a trimeric hairpin conformation, thus driving the fusion reaction. The means by which E1 senses and responds to low pH is unclear, and protonation of conserved E1 histidine residues has been proposed as a possible mechanism. We tested the role of four conserved histidines by mutagenesis of the wild-type (wt) SFV infectious clone to create virus mutants with E1 H3A, H125A, H331A, and H331A/H333A mutations. The H125A, H331A, and H331A/H333A mutants had growth properties similar to those of wt SFV and showed modest change or no change in the pH dependence of virus-membrane fusion. By contrast, the E1 H3A mutation produced impaired virus growth and a markedly more acidic pH requirement for virus-membrane fusion. The dissociation of the H3A heterodimer and the membrane insertion of the mutant E1 protein were comparable to those of the wt in efficiency and pH dependence. However, the formation of the H3A homotrimer required a much lower pH and showed reduced efficiency. Together, these results and the location of H3 suggest that this residue acts to regulate the low-pH-dependent refolding of E1 during membrane fusion.

  8. Presence and removal of a contaminating NADH oxidation activity in recombinant maltose-binding protein fusion proteins expressed in Escherichia coli.

    Science.gov (United States)

    Guo, Fengguang; Zhu, Guan

    2012-04-01

    We observed the presence of contaminating NADH oxidation activity in maltose binding protein (MBP) fusion proteins expressed in Escherichia coli and purified using conventional amylose resin-based affinity chromatography. This contaminating NADH oxidation activity was detectable with at least four different enzymes from Cryptosporidium parvum expressed as MBP-fusion proteins (i.e., an enoyl-reductase domain from a type I fatty acid synthase, a fatty acyl-CoA binding protein, the acyl-ligase domain from a polyketide synthase, and a putative thioesterase), regardless of their NADH dependence. However, contaminating NADH oxidation activity was not present when fusion proteins were engineered to contain a His-tag and were purified using a Ni-NTA resin-based protocol. Alternatively, for proteins containing only an MBP-tag, the contaminating activity could be eliminated through the addition of 0.1% Triton X-100 and 2% glycerol to the column buffer during homogenization of bacteria and first column wash, followed by an additional wash and elution with regular column and elution buffers. Removal of the artifactual activity is very valuable in the study of enzymes using NADH as a cofactor, particularly when the native activity is low or the recombinant proteins are inactive.

  9. Different sets of ER-resident J-proteins regulate distinct polar nuclear-membrane fusion events in Arabidopsis thaliana.

    Science.gov (United States)

    Maruyama, Daisuke; Yamamoto, Masaya; Endo, Toshiya; Nishikawa, Shuh-ichi

    2014-11-01

    Angiosperm female gametophytes contain a central cell with two polar nuclei. In many species, including Arabidopsis thaliana, the polar nuclei fuse during female gametogenesis. We previously showed that BiP, an Hsp70 in the endoplasmic reticulum (ER), was essential for membrane fusion during female gametogenesis. Hsp70 function requires partner proteins for full activity. J-domain containing proteins (J-proteins) are the major Hsp70 functional partners. A. thaliana ER contains three soluble J-proteins, AtERdj3A, AtERdj3B, and AtP58(IPK). Here, we analyzed mutants of these proteins and determined that double-mutant ovules lacking AtP58(IPK) and AtERdj3A or AtERdj3B were defective in polar nuclear fusion. Electron microscopy analysis identified that polar nuclei were in close contact, but no membrane fusion occurred in mutant ovules lacking AtP58(IPK) and AtERdj3A. The polar nuclear outer membrane appeared to be connected via the ER remaining at the inner unfused membrane in mutant ovules lacking AtP58(IPK) and AtERdj3B. These results indicate that ER-resident J-proteins, AtP58(IPK)/AtERdj3A and AtP58(IPK)/AtERdj3B, function at distinct steps of polar nuclear-membrane fusion. Similar to the bip1 bip2 double mutant female gametophytes, the aterdj3a atp58(ipk) double mutant female gametophytes defective in fusion of the outer polar nuclear membrane displayed aberrant endosperm proliferation after fertilization with wild-type pollen. However, endosperm proliferated normally after fertilization of the aterdj3b atp58(ipk) double mutant female gametophytes defective in fusion of the inner membrane. Our results indicate that the polar nuclear fusion defect itself does not cause an endosperm proliferation defect. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  10. Crystal Structure of the Membrane Fusion Protein CusB from Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Su, Chih-Chia; Yang, Feng; Long, Feng; Reyon, Deepak; Routh, Mathew D.; Kuo, Dennis W.; Mokhtari, Adam K.; Van Ornam, Jonathan D.; Rabe, Katherine L.; Hoy, Julie A.; Lee, Young Jin; Rajashankar, Kanagalaghatta R.; Yu, Edward W.; (Cornell); (Iowa State)

    2010-03-29

    Gram-negative bacteria, such as Escherichia coli, frequently utilize tripartite efflux complexes belonging to the resistance-nodulation-division family to expel diverse toxic compounds from the cell. These systems contain a periplasmic membrane fusion protein (MFP) that is critical for substrate transport. We here present the x-ray structures of the CusB MFP from the copper/silver efflux system of E. coli. This is the first structure of any MFPs associated with heavy-metal efflux transporters. CusB bridges the inner-membrane efflux pump CusA and outer-membrane channel CusC to mediate resistance to Cu{sup +} and Ag{sup +} ions. Two distinct structures of the elongated molecules of CusB were found in the asymmetric unit of a single crystal, which suggests the flexible nature of this protein. Each protomer of CusB can be divided into four different domains, whereby the first three domains are mostly {beta}-strands and the last domain adopts an entirely helical architecture. Unlike other known structures of MFPs, the {alpha}-helical domain of CusB is folded into a three-helix bundle. This three-helix bundle presumably interacts with the periplasmic domain of CusC. The N- and C-termini of CusB form the first {beta}-strand domain, which is found to interact with the periplasmic domain of the CusA efflux pump. Atomic details of how this efflux protein binds Cu{sup +} and Ag{sup +} were revealed by the crystals of the CusB-Cu(I) and CusB-Ag(I) complexes. The structures indicate that CusB consists of multiple binding sites for these metal ions. These findings reveal novel structural features of an MFP in the resistance-nodulation-division efflux system and provide direct evidence that this protein specifically interacts with transported substrates.

  11. Genetic diversity and evolution of human metapneumovirus fusion protein over twenty years

    Directory of Open Access Journals (Sweden)

    Liem Alexis

    2009-09-01

    Full Text Available Abstract Background Human metapneumovirus (HMPV is an important cause of acute respiratory illness in children. We examined the diversity and molecular evolution of HMPV using 85 full-length F (fusion gene sequences collected over a 20-year period. Results The F gene sequences fell into two major groups, each with two subgroups, which exhibited a mean of 96% identity by predicted amino acid sequences. Amino acid identity within and between subgroups was higher than nucleotide identity, suggesting structural or functional constraints on F protein diversity. There was minimal progressive drift over time, and the genetic lineages were stable over the 20-year period. Several canonical amino acid differences discriminated between major subgroups, and polymorphic variations tended to cluster in discrete regions. The estimated rate of mutation was 7.12 × 10-4 substitutions/site/year and the estimated time to most recent common HMPV ancestor was 97 years (95% likelihood range 66-194 years. Analysis suggested that HMPV diverged from avian metapneumovirus type C (AMPV-C 269 years ago (95% likelihood range 106-382 years. Conclusion HMPV F protein remains conserved over decades. HMPV appears to have diverged from AMPV-C fairly recently.

  12. Genetic diversity and evolution of human metapneumovirus fusion protein over twenty years

    Science.gov (United States)

    Yang, Chin-Fen; Wang, Chiaoyin K; Tollefson, Sharon J; Piyaratna, Rohith; Lintao, Linda D; Chu, Marla; Liem, Alexis; Mark, Mary; Spaete, Richard R; Crowe, James E; Williams, John V

    2009-01-01

    Background Human metapneumovirus (HMPV) is an important cause of acute respiratory illness in children. We examined the diversity and molecular evolution of HMPV using 85 full-length F (fusion) gene sequences collected over a 20-year period. Results The F gene sequences fell into two major groups, each with two subgroups, which exhibited a mean of 96% identity by predicted amino acid sequences. Amino acid identity within and between subgroups was higher than nucleotide identity, suggesting structural or functional constraints on F protein diversity. There was minimal progressive drift over time, and the genetic lineages were stable over the 20-year period. Several canonical amino acid differences discriminated between major subgroups, and polymorphic variations tended to cluster in discrete regions. The estimated rate of mutation was 7.12 × 10-4 substitutions/site/year and the estimated time to most recent common HMPV ancestor was 97 years (95% likelihood range 66-194 years). Analysis suggested that HMPV diverged from avian metapneumovirus type C (AMPV-C) 269 years ago (95% likelihood range 106-382 years). Conclusion HMPV F protein remains conserved over decades. HMPV appears to have diverged from AMPV-C fairly recently. PMID:19740442

  13. Strangvac: A recombinant fusion protein vaccine that protects against strangles, caused by Streptococcus equi.

    Science.gov (United States)

    Robinson, Carl; Frykberg, Lars; Flock, Margareta; Guss, Bengt; Waller, Andrew S; Flock, Jan-Ingmar

    2018-03-07

    The host-restricted pathogen Streptococcus equi causes strangles in the horse, which is characterised by abscessation of the lymph nodes of the head and neck. The disease is endemic throughout the world causing considerable welfare and economic cost to the horse industry. Here we report the results of three studies where ponies were vaccinated with combinations of recombinant fusion proteins to optimise vaccine production and the level of protection conferred. Optimal protection was conferred by a prototype multicomponent subunit vaccine, Strangvac 4, which contained eight proteins CNE, SclC, SclF, SclI, EAG (fused as CCE), SEQ_402, SEQ_0256 (fused as Eq85) and IdeE. Across the three experiments only three of 16 ponies vaccinated with Strangvac 4 became pyretic compared to all 16 placebo-vaccinated control ponies (P equi was recovered from the lymph nodes of eight Strangvac 4-vaccinated and 15 control ponies (P = .016). None of the ponies vaccinated with Strangvac 4, or the other prototype vaccines developed adverse reactions following vaccination. Our data provide evidence in support of the further clinical development of the Strangvac 4 vaccine. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Novel antibody-cytokine fusion proteins featuring granulocyte-colony stimulating factor, interleukin-3 and interleukin-4 as payloads.

    Science.gov (United States)

    Schmid, Anja Sophie; Tintor, Diana; Neri, Dario

    2018-04-10

    Neutrophils can strongly influence disease activity in cancer and in chronic inflammation. Here, we report for the first time the construction and characterization of antibody-fusion proteins featuring granulocyte-colony stimulating factor and interleukin-3 as payloads capable of enhancing neutrophil activity and a novel antibody-interleukin-4 fusion protein with neutrophil inhibitory potential. We used the F8 antibody specific to the alternatively-spliced extra domain A (EDA) of fibronectin as a targeting agent, since the cognate antigen is strongly upregulated in diseases characterized by angiogenesis. The fusion proteins GCSF-F8, F8-IL3 and F8-IL4-F8, were cloned, expressed, and their targeting ability assessed, exhibiting preferential tumor uptake with tumor:blood ratios at 24 h after injection of 3.3, 18.2 and 27.3, respectively. In F9 tumor bearing-mice GCSF-F8 and F8-IL3 did not provide a therapeutic benefit, while F8-IL4-F8 showed a potent tumor growth retardation. In the collagen-induced model of arthritis, GCSF-F8 and F8-IL3 induced a worsening of the disease, while F8-IL4-F8 slowed arthritis progression but, surprisingly, exhibited substantial toxicity when used in combination with dexamethasone. Collectively, the results indicate that the novel fusion proteins could be expressed and efficiently delivered to the site of disease. However, they were not superior to other antibody-cytokine fusions previously described by our laboratory. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Inhibition of protein translation by the DISC1-Boymaw fusion gene from a Scottish family with major psychiatric disorders.

    Science.gov (United States)

    Ji, Baohu; Higa, Kerin K; Kim, Minjung; Zhou, Lynn; Young, Jared W; Geyer, Mark A; Zhou, Xianjin

    2014-11-01

    The t(1; 11) translocation appears to be the causal genetic lesion with 70% penetrance for schizophrenia, major depression and other psychiatric disorders in a Scottish family. Molecular studies identified the disruption of the disrupted-in-schizophrenia 1 (DISC1) gene by chromosome translocation at chromosome 1q42. Our previous studies, however, revealed that the translocation also disrupted another gene, Boymaw (also termed DISC1FP1), on chromosome 11. After translocation, two fusion genes [the DISC1-Boymaw (DB7) and the Boymaw-DISC1 (BD13)] are generated between the DISC1 and Boymaw genes. In the present study, we report that expression of the DB7 fusion gene inhibits both intracellular NADH oxidoreductase activities and protein translation. We generated humanized DISC1-Boymaw mice with gene targeting to examine the in vivo functions of the fusion genes. Consistent with the in vitro studies on the DB7 fusion gene, protein translation activity is decreased in the hippocampus and in cultured primary neurons from the brains of the humanized mice. Expression of Gad67, Nmdar1 and Psd95 proteins are also reduced. The humanized mice display prolonged and increased responses to the NMDA receptor antagonist, ketamine, on various mouse genetic backgrounds. Abnormal information processing of acoustic startle and depressive-like behaviors are also observed. In addition, the humanized mice display abnormal erythropoiesis, which was reported to associate with depression in humans. Expression of the DB7 fusion gene may reduce protein translation to impair brain functions and thereby contribute to the pathogenesis of major psychiatric disorders. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Immunogenicity of a cholera toxin B subunit Porphyromonas gingivalis fimbrial antigen fusion protein expressed in E. coli.

    Science.gov (United States)

    Kim, Tae-Geum; Huy, Nguyen-Xuan; Kim, Mi-Young; Jeong, Dong-Keun; Jang, Yong-Suk; Yang, Moon-Sik; Langridge, William H R; Lee, Jin-Yong

    2009-02-01

    The gram-negative anaerobic oral bacterium Porphyromonas gingivalis initiates periodontal disease through fimbrial attachment to saliva-coated oral surfaces. To study the effects of immunomodulation on enhancement of subunit vaccination, the expression in E. coli and immunogenicity of P. gingivalis fimbrial protein (FimA) linked to the C-terminus of the cholera toxin B subunit (CTB) were investigated. Complementary DNAs encoding the P. gingivalis 381 fimbrillin protein sequence FimA1 (amino acid residues 1-200) and FimA2 (amino acid residues 201-337) were cloned into an E. coli expression vector downstream of a cDNA fragment encoding the immunostimulatory CTB. CTB-FimA1 and CTB-FimA2 fusion proteins synthesized in E. coli BL21 (DE3) cells were purified under denaturing conditions by Ni2+-NTA affinity column chromatography. Renaturation of the CTB-FimA1 and CTB-FimA2 fusion proteins, permitted identification of CTB-FimA pentamers and restored CTB binding activity to GM1-ganglioside to provide a biologically active CTB-FimA fusion protein. Mice orally inoculated with purified CTB-FimA1 or CTB-FimA2 fusion proteins generated measurable FimA1 and FimA2 IgG antibody titers, while no serum fimbrial IgG antibodies were detected when mice were inoculated with FimA1 or FimA2 proteins alone. Immunoblot analysis confirmed that sera from mice immunized with CTB linked to FimA1 or FimA2 contained antibodies specific for P. gingivalis fimbrial proteins. In addition, mice immunized with FimA2 or CTB-FimA2 generated measurable intestinal IgA titers indicating the presence of fimbrial antibody class switching. Further, mice orally immunized with CTB-FimA1 generated higher IgA antibody titers than mice inoculated with FimA1 alone. The experimental data show that the immunostimulatory molecule CTB enhances B cell-mediated immunity against linked P. gingivalis FimA fusion proteins, in comparison to immunization with FimA protein alone. Thus, linkage of CTB to P. gingivalis fimbrial

  17. Silk-Silk Interactions between Silkworm Fibroin and Recombinant Spider Silk Fusion Proteins Enable the Construction of Bioactive Materials.

    Science.gov (United States)

    Nilebäck, Linnea; Chouhan, Dimple; Jansson, Ronnie; Widhe, Mona; Mandal, Biman B; Hedhammar, My

    2017-09-20

    Natural silk is easily accessible from silkworms and can be processed into different formats suitable as biomaterials and cell culture matrixes. Recombinant DNA technology enables chemical-free functionalization of partial silk proteins through fusion with peptide motifs and protein domains, but this constitutes a less cost-effective production process. Herein, we show that natural silk fibroin (SF) can be used as a bulk material that can be top-coated with a thin layer of the recombinant spider silk protein 4RepCT in fusion with various bioactive motifs and domains. The coating process is based on a silk assembly to achieve stable interactions between the silk types under mild buffer conditions. The assembly process was studied in real time by quartz crystal microbalance with dissipation. Coatings, electrospun mats, and microporous scaffolds were constructed from Antheraea assama and Bombyx mori SFs. The morphology of the fibroin materials before and after coating with recombinant silk proteins was analyzed by scanning electron microscopy and atomic force microscopy. SF materials coated with various bioactive 4RepCT fusion proteins resulted in directed antibody capture, enzymatic activity, and improved cell attachment and spreading, respectively, compared to pristine SF materials. The herein-described procedure allows a fast and easy route for the construction of bioactive materials.

  18. A strategy for targeting recombinant proteins to protein storage vacuoles by fusion to Brassica napus napin in napin-depleted seeds.

    Science.gov (United States)

    Hegedus, Dwayne D; Baron, Marcus; Labbe, Natalie; Coutu, Cathy; Lydiate, Derek; Lui, Helen; Rozwadowski, Kevin

    2014-03-01

    Seeds are capable of accumulating high levels of seed storage proteins (SSP), as well as heterologous proteins under certain conditions. Arabidopsis thaliana was used to develop a strategy to deplete seeds of an endogenous SSP and then replenish them with the same protein fused to a heterologous protein. In several other studies, competition with endogenous SSP for space and metabolic resources was shown to affect the accumulation of recombinant proteins in seeds. We used RNAi to reduce the expression of the five napin genes and deplete the seeds of this SSP. Targeting a recombinant protein to a vacuole or structure within the seed where it can be protected from cytosolic proteases can also promote its accumulation. To achieve this, a synthetic Brassica napus napin gene (Bn napin) was designed that was both impervious to the A. thaliana napin (At napin) RNAi construct and permitted fusion to a heterologous protein, in this case green fluorescent protein (GFP). GFP was placed in several strategic locations within Bn napin with consideration to maintaining structure, processing sites and possible vacuolar targeting signals. In transgenic A. thaliana plants, GFP was strongly localized to the seed protein storage vacuole in all Bn napin fusion configurations tested, but not when expressed alone. This SSP depletion-replenishment strategy outlined here would be applicable to expression of recombinant proteins in industrial crops that generally have large repertoires of endogenous SSP genes. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  19. Two active molecular phenotypes of the tachykinin NK1 receptor revealed by G-protein fusions and mutagenesis

    DEFF Research Database (Denmark)

    Holst, B; Hastrup, H; Raffetseder, U

    2001-01-01

    either Galpha(s) or Galpha(q) and the NK1 receptor with a truncated tail, which secured non-promiscuous G-protein interaction, demonstrated monocomponent agonist binding closely corresponding to either of the two affinity states found in the wild-type receptor. High affinity binding of both substance P...... and neurokinin A was observed in the tail-truncated Galpha(s) fusion construct, whereas the lower affinity component was displayed by the tail-truncated Galpha(q) fusion. The elusive difference between the affinity determined in heterologous versus homologous binding assays for substance P and especially...... in the tail-truncated Galpha(q) fusion construct. Thus, the heterogenous pharmacological phenotype displayed by the NK1 receptor is a reflection of the occurrence of two active conformations or molecular phenotypes representing complexes with the Galpha(s) and Galpha(q) species, respectively. We propose...

  20. A mutation in the envelope protein fusion loop attenuates mouse neuroinvasiveness of the NY99 strain of West Nile virus

    International Nuclear Information System (INIS)

    Zhang Shuliu; Li Li; Woodson, Sara E.; Huang, Claire Y.-H.; Kinney, Richard M.; Barrett, Alan D.T.; Beasley, David W.C.

    2006-01-01

    Substitutions were engineered individually and in combinations at the fusion loop, receptor-binding domain and a stem-helix structure of the envelope protein of a West Nile virus strain, NY99, and their effects on mouse virulence and presentation of epitopes recognized by monoclonal antibodies (MAbs) were assessed. A single substitution within the fusion loop (L107F) attenuated mouse neuroinvasiveness of NY99. No substitutions attenuated NY99 neurovirulence. The L107F mutation also abolished binding of a non-neutralizing MAb, 3D9, whose epitope had not been previously identified. MAb 3D9 was subsequently shown to be broadly cross-reactive with other flaviviruses, consistent with binding near the highly conserved fusion loop

  1. FOXO1 is a direct target of EWS-Fli1 oncogenic fusion protein in Ewing's sarcoma cells

    International Nuclear Information System (INIS)

    Yang, Liu; Hu, Hsien-Ming; Zielinska-Kwiatkowska, Anna; Chansky, Howard A.

    2010-01-01

    Research highlights: → Inducible and reversible siRNA knockdown of an oncogenic fusion protein such as EWS-Fli1 is feasible and more advantageous than other siRNA methods. → The tumor suppressor gene FOXO1 is a new EWS-Fli1 target. → While trans-activators are known for the FOXO1 gene, there has been no report on negative regulators of FOXO1 transcription. → This study provides first evidence that the EWS-Fli1 oncogenic fusion protein can function as a transcriptional repressor of the FOXO1 gene. -- Abstract: Ewing's family tumors are characterized by a specific t(11;22) chromosomal translocation that results in the formation of EWS-Fli1 oncogenic fusion protein. To investigate the effects of EWS-Fli1 on gene expression, we carried out DNA microarray analysis after specific knockdown of EWS-Fli1 through transfection of synthetic siRNAs. EWS-Fli1 knockdown increased expression of genes such as DKK1 and p57 that are known to be repressed by EWS-Fli1 fusion protein. Among other potential EWS-Fli1 targets identified by our microarray analysis, we have focused on the FOXO1 gene since it encodes a potential tumor suppressor and has not been previously reported in Ewing's cells. To better understand how EWS-Fli1 affects FOXO1 expression, we have established a doxycycline-inducible siRNA system to achieve stable and reversible knockdown of EWS-Fli1 in Ewing's sarcoma cells. Here we show that FOXO1 expression in Ewing's cells has an inverse relationship with EWS-Fli1 protein level, and FOXO1 promoter activity is increased after doxycycline-induced EWS-Fli1 knockdown. In addition, we have found that direct binding of EWS-Fli1 to FOXO1 promoter is attenuated after doxycycline-induced siRNA knockdown of the fusion protein. Together, these results suggest that suppression of FOXO1 function by EWS-Fli1 fusion protein may contribute to cellular transformation in Ewing's family tumors.

  2. Cell-to-Cell Measles Virus Spread between Human Neurons Is Dependent on Hemagglutinin and Hyperfusogenic Fusion Protein.

    Science.gov (United States)

    Sato, Yuma; Watanabe, Shumpei; Fukuda, Yoshinari; Hashiguchi, Takao; Yanagi, Yusuke; Ohno, Shinji

    2018-03-15

    Measles virus (MV) usually causes acute infection but in rare cases persists in the brain, resulting in subacute sclerosing panencephalitis (SSPE). Since human neurons, an important target affected in the disease, do not express the known MV receptors (signaling lymphocyte activation molecule [SLAM] and nectin 4), how MV infects neurons and spreads between them is unknown. Recent studies have shown that many virus strains isolated from SSPE patients possess substitutions in the extracellular domain of the fusion (F) protein which confer enhanced fusion activity. Hyperfusogenic viruses with such mutations, unlike the wild-type MV, can induce cell-cell fusion even in SLAM- and nectin 4-negative cells and spread efficiently in human primary neurons and the brains of animal models. We show here that a hyperfusogenic mutant MV, IC323-F(T461I)-EGFP (IC323 with a fusion-enhancing T461I substitution in the F protein and expressing enhanced green fluorescent protein), but not the wild-type MV, spreads in differentiated NT2 cells, a widely used human neuron model. Confocal time-lapse imaging revealed the cell-to-cell spread of IC323-F(T461I)-EGFP between NT2 neurons without syncytium formation. The production of virus particles was strongly suppressed in NT2 neurons, also supporting cell-to-cell viral transmission. The spread of IC323-F(T461I)-EGFP was inhibited by a fusion inhibitor peptide as well as by some but not all of the anti-hemagglutinin antibodies which neutralize SLAM- or nectin-4-dependent MV infection, suggesting the presence of a distinct neuronal receptor. Our results indicate that MV spreads in a cell-to-cell manner between human neurons without causing syncytium formation and that the spread is dependent on the hyperfusogenic F protein, the hemagglutinin, and the putative neuronal receptor for MV. IMPORTANCE Measles virus (MV), in rare cases, persists in the human central nervous system (CNS) and causes subacute sclerosing panencephalitis (SSPE) several

  3. A fusion protein consisting of the exopeptidases PepN and PepX-production, characterization, and application.

    Science.gov (United States)

    Stressler, Timo; Pfahler, Nina; Merz, Michael; Hubschneider, Larissa; Lutz-Wahl, Sabine; Claaßen, Wolfgang; Fischer, Lutz

    2016-09-01

    Nowadays, general and specific aminopeptidases are of great interest, especially for protein hydrolysis in the food industry. As shown previously, it is confirmed that the general aminopeptidase N (PepN; EC 3.4.11.2) and the proline-specific peptidase PepX (EC 3.4.14.11) from Lactobacillus helveticus ATCC 12046 show a synergistic effect during protein hydrolysis which results in high degrees of hydrolysis and reduced bitterness. To combine both activities, the enzymes were linked and a fusion protein called PepN-L1-PepX (FUS-PepN-PepX) was created. After production and purification, the fusion protein was characterized. Some of its biochemical characteristics were altered in favor for an application compared to the single enzymes. As an example, the optimum temperature for the PepN activity increased from 30 °C for the single enzyme to 35 °C for FUS-PepN. In addition, the temperature stability of PepX was higher for FUS-PepX than for the single enzyme (50 % compared to 40 % residual activity at 50 °C after 14 days, respectively). In addition, the disulfide bridge-reducing reagent β-mercaptoethanol did not longer inactivate the FUS-PepN activity. Furthermore, the K M values decreased for both enzyme activities in the fusion protein. Finally, it was found that the synergistic hydrolysis performance in a casein hydrolysis was not reduced for the fusion protein. The increase of the relative degree of hydrolysis of a prehydrolyzed casein solution was the same as it was for the single enzymes. As a benefit, the resulting hydrolysate showed a strong antioxidative capacity (ABTS-IC50 value: 5.81 μg mL(-1)).

  4. A substrate-fusion protein is trapped inside the Type III Secretion System channel in Shigella flexneri.

    Directory of Open Access Journals (Sweden)

    Kim Dohlich

    2014-01-01

    Full Text Available The Type III Secretion System (T3SS is a macromolecular complex used by Gram-negative bacteria to secrete effector proteins from the cytoplasm across the bacterial envelope in a single step. For many pathogens, the T3SS is an essential virulence factor that enables the bacteria to interact with and manipulate their respective host. A characteristic structural feature of the T3SS is the needle complex (NC. The NC resembles a syringe with a basal body spanning both bacterial membranes and a long needle-like structure that protrudes from the bacterium. Based on the paradigm of a syringe-like mechanism, it is generally assumed that effectors and translocators are unfolded and secreted from the bacterial cytoplasm through the basal body and needle channel. Despite extensive research on T3SS, this hypothesis lacks experimental evidence and the mechanism of secretion is not fully understood. In order to elucidate details of the T3SS secretion mechanism, we generated fusion proteins consisting of a T3SS substrate and a bulky protein containing a knotted motif. Because the knot cannot be unfolded, these fusions are accepted as T3SS substrates but remain inside the NC channel and obstruct the T3SS. To our knowledge, this is the first time substrate fusions have been visualized together with isolated NCs and we demonstrate that substrate proteins are secreted directly through the channel with their N-terminus first. The channel physically encloses the fusion protein and shields it from a protease and chemical modifications. Our results corroborate an elementary understanding of how the T3SS works and provide a powerful tool for in situ-structural investigations in the future. This approach might also be applicable to other protein secretion systems that require unfolding of their substrates prior to secretion.

  5. Antibody-Induced Internalization of the Human Respiratory Syncytial Virus Fusion Protein.

    Science.gov (United States)

    Leemans, A; De Schryver, M; Van der Gucht, W; Heykers, A; Pintelon, I; Hotard, A L; Moore, M L; Melero, J A; McLellan, J S; Graham, B S; Broadbent, L; Power, U F; Caljon, G; Cos, P; Maes, L; Delputte, P

    2017-07-15

    Respiratory syncytial virus (RSV) infections remain a major cause of respiratory disease and hospitalizations among infants. Infection recurs frequently and establishes a weak and short-lived immunity. To date, RSV immunoprophylaxis and vaccine research is mainly focused on the RSV fusion (F) protein, but a vaccine remains elusive. The RSV F protein is a highly conserved surface glycoprotein and is the main target of neutralizing antibodies induced by natural infection. Here, we analyzed an internalization process of antigen-antibody complexes after binding of RSV-specific antibodies to RSV antigens expressed on the surface of infected cells. The RSV F protein and attachment (G) protein were found to be internalized in both infected and transfected cells after the addition of either RSV-specific polyclonal antibodies (PAbs) or RSV glycoprotein-specific monoclonal antibodies (MAbs), as determined by indirect immunofluorescence staining and flow-cytometric analysis. Internalization experiments with different cell lines, well-differentiated primary bronchial epithelial cells (WD-PBECs), and RSV isolates suggest that antibody internalization can be considered a general feature of RSV. More specifically for RSV F, the mechanism of internalization was shown to be clathrin dependent. All RSV F-targeted MAbs tested, regardless of their epitopes, induced internalization of RSV F. No differences could be observed between the different MAbs, indicating that RSV F internalization was epitope independent. Since this process can be either antiviral, by affecting virus assembly and production, or beneficial for the virus, by limiting the efficacy of antibodies and effector mechanism, further research is required to determine the extent to which this occurs in vivo and how this might impact RSV replication. IMPORTANCE Current research into the development of new immunoprophylaxis and vaccines is mainly focused on the RSV F protein since, among others, RSV F-specific antibodies are

  6. Fusion Machinery

    DEFF Research Database (Denmark)

    Sørensen, Jakob Balslev; Milosevic, Ira

    2015-01-01

    SNARE proteins constitute the minimal machinery needed for membrane fusion. SNAREs operate by forming a complex, which pulls the lipid bilayers into close contact and provides the mechanical force needed for lipid bilayer fusion. At the chemical synapse, SNARE-complex formation between...... the vesicular SNARE VAMP2/synaptobrevin-2 and the target (plasma membrane) SNAREs SNAP25 and syntaxin-1 results in fusion and release of neurotransmitter, synchronized to the electrical activity of the cell by calcium influx and binding to synaptotagmin. Formation of the SNARE complex is tightly regulated...... and appears to start with syntaxin-1 bound to an SM (Sec1/Munc18-like) protein. Proteins of the Munc13-family are responsible for opening up syntaxin and allowing sequential binding of SNAP-25 and VAMP2/synaptobrevin-2. N- to C-terminal “zippering” of the SNARE domains leads to membrane fusion...

  7. [Targeted tumor suppression by a secreted fusion protein consisting of anti- erbB2 antibody and reversed caspase-3 to SKBr3 cells].

    Science.gov (United States)

    Zhang, Li-hong; Jia, Lin-tao; Yu, Cui-juan; Qu, Ping; Dong, Hai-long; Zhao, Jing; Xu, Yan-ming; Wang, Cheng-Ji; Yang, An-gang

    2003-04-10

    To investigate the targeted killing effect to SKBr3 cells due to the expression of a secreted fusion protein consisting of anti-erbB2 antibody and reversed caspase-3. A recombinant plasmid pCMV-e23scFv-PEII-revcasp 3 was constructed by subcloning reversed caspase-3 gene to the downstream of anti-erbB2 antibody and transfected into Jurkat cells. The cell lines which secreted expressing fusion protein stably were selected. The fusion protein in media was detected by ELISA and the media was used to culture human breast cancer SKBr3 cells. The recombinant plasmids with liposomes was administrated to BALB/C nude mouses bearing SKBr3 tumor by intramuscular injection. The targetting effect of the recombinant fusion protein caspase-3 was detected by indirect immunofluorescence staining. Fusion protein can be expressed and secreted by Jurkat cells stably and kill SKBr3 cells. Significant prolonged survival time (prolonged by 72%) and inhibition of tumor growth in vivo (within inhibition ratio of 77%) were seen in the group administered with recombinant plasmids. Indirect immunofluorescence staining showed that the recombinant fusion protein caspase-3 has targetting effect. Secreted expression of the fusion protein consisting of anti-erbB2 antibody and reversed caspase-3 can targetedly induce SKBr3 cells to death.

  8. Using Haloarcula marismortui bacteriorhodopsin as a fusion tag for enhancing and visible expression of integral membrane proteins in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Min-Feng Hsu

    Full Text Available Membrane proteins are key targets for pharmacological intervention because of their vital functions. Structural and functional studies of membrane proteins have been severely hampered because of the difficulties in producing sufficient quantities of properly folded and biologically active proteins. Here we generate a high-level expression system of integral membrane proteins in Escherichia coli by using a mutated bacteriorhodopsin (BR from Haloarcula marismortui (HmBRI/D94N as a fusion partner. A purification strategy was designed by incorporating a His-tag on the target membrane protein for affinity purification and an appropriate protease cleavage site to generate the final products. The fusion system can be used to detect the intended target membrane proteins during overexpression and purification either with the naked eye or by directly monitoring their characteristic optical absorption. In this study, we applied this approach to produce two functional integral membrane proteins, undecaprenyl pyrophosphate phosphatase and carnitine/butyrobetaine antiporter with significant yield enhancement. This technology could facilitate the development of a high-throughput strategy to screen for conditions that improve the yield of correctly folded target membrane proteins. Other robust BRs can also be incorporated in this system.

  9. Mannosylated mucin-type immunoglobulin fusion proteins enhance antigen-specific antibody and T lymphocyte responses.

    Directory of Open Access Journals (Sweden)

    Gustaf Ahlén

    Full Text Available Targeting antigens to antigen-presenting cells (APC improve their immunogenicity and capacity to induce Th1 responses and cytotoxic T lymphocytes (CTL. We have generated a mucin-type immunoglobulin fusion protein (PSGL-1/mIgG(2b, which upon expression in the yeast Pichia pastoris became multivalently substituted with O-linked oligomannose structures and bound the macrophage mannose receptor (MMR and dendritic cell-specific intercellular adhesion molecule-3 grabbing non-integrin (DC-SIGN with high affinity in vitro. Here, its effects on the humoral and cellular anti-ovalbumin (OVA responses in C57BL/6 mice are presented.OVA antibody class and subclass responses were determined by ELISA, the generation of anti-OVA CTLs was assessed in (51Cr release assays using in vitro-stimulated immune spleen cells from the different groups of mice as effector cells and OVA peptide-fed RMA-S cells as targets, and evaluation of the type of Th cell response was done by IFN-γ, IL-2, IL-4 and IL-5 ELISpot assays.Immunizations with the OVA - mannosylated PSGL-1/mIgG(2b conjugate, especially when combined with the AbISCO®-100 adjuvant, lead to faster, stronger and broader (with regard to IgG subclass OVA IgG responses, a stronger OVA-specific CTL response and stronger Th1 and Th2 responses than if OVA was used alone or together with AbISCO®-100. Also non-covalent mixing of mannosylated PSGL-1/mIgG(2b, OVA and AbISCO®-100 lead to relatively stronger humoral and cellular responses. The O-glycan oligomannoses were necessary because PSGL-1/mIgG(2b with mono- and disialyl core 1 structures did not have this effect.Mannosylated mucin-type fusion proteins can be used as versatile APC-targeting molecules for vaccines and as such enhance both humoral and cellular immune responses.

  10. [A standardized protocol for detection of ALK protein expression and gene fusion in lung adenocarcinoma cytologic specimens].

    Science.gov (United States)

    Wang, Zheng; Wu, Xiaonan; Shi, Yuankai; Han, Xiaohong; Cheng, Gang; Li, Lin; Mu, Xinlin; Zhang, Yuhui; Cui, Di; Zhang, Li; Fan, Zaiwen; Zhu, Guangqing; Ma, Lingyun; Yang, Li; Di, Jing; Liu, Dongge

    2015-10-01

    The aim of this study was to establish a standardized protocol for detection of ALK protein expression and gene fusion in cytologic specimens. Lung adenocarcinoma cytologic specimens were collected from seven hospitals in Beijing city. A detection protocol for ALK protein expression and gene fusion was designed according to the results of comparative experiment. Ventana immunohistochemical (IHC) ALK(D5F3) detecting ALK protein expression was performed in 203 prepared formalin-fixed paraffin-embedded (FFPE) cell blocks. ALK gene fusion in 98 EGFR gene wild type cytologic specimens and in 4 bronchoalveolar lavage fluid (BL) samples was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). ALK gene fusion in the Ventana IHC ALK (D5F3) positive samples was further tested by fluorescence in situ hybridization (FISH). Six patients with ALK IHC-positive result were followed up to analyze the responses of crizotinib therapy. Comparative experiments: (1) Comparison of the results of 4% neutral buffered formalin fixed for different time (24 h, 48 h, 72 h) on the Ventana IHC ALK (D5F3) staining was conducted in two cases of IHC ALK positive FFPE cell blocks; (2) Comparing qRT-PCR results for ALK fusion in samples from FFPE cell blocks and cytospin prepared slides in 10 cases of lung adenocarcinoma cytologic specimens. Among the specimens examined using the standardized protocol recommended by this study, 229 cases of cytologic specimens met the diagnostic criteria of lung adenocarcinoma. Among them, 207 cases obtained ALK gene test results (by at least one method), with an ALK test ratio of 90.4% (207/229). FFPE cell blocks were successfully prepared in 203 cases, Ventana IHC ALK (D5F3) were successfully performed in all the 203 FFPE cell blocks (100%), and the ALK protein positive detection rate was 10.3% (21/203). ALK fusion was tested in 98 FFPE cytologic samples of EGFR wild types by qRT-PCR, and 96 out of 98 (97.96%) cytologic samples were

  11. A Generic Protocol for Purifying Disulfide-Bonded Domains and Random Protein Fragments Using Fusion Proteins with SUMO3 and Cleavage by SenP2 Protease.

    Science.gov (United States)

    Besir, Hüseyin

    2017-01-01

    Recombinant expression of heterologous proteins in E. coli is well established for a wide range of proteins, although in many cases, purifying soluble and properly folded proteins remains challenging (Sorensen and Mortensen, J Biotechnol 115:113-128, 2005; Correa and Oppezzo, Methods Mol Biol 1258:27-44, 2015). Proteins that contain disulfide bonds (e.g., cytokines, growth factors) are often particularly difficult to purify in soluble form and still need optimizing of protocols in almost every step of the process (Berkmen, Protein Expr Purif 82:240-251, 2012; de Marco, Microb Cell Fact 11:129, 2012). Expression of disulfide bonded proteins in the periplasm of E. coli is one approach that can help to obtain soluble protein with the correct disulfide bridges forming in the periplasm. This offers the appropriate conditions for disulfide formation although periplasmic expression can also result in low expression levels and incorrect folding of the target protein (Schlapschy and Skerra, Methods Mol Biol 705:211-224, 2011). Generation of specific antibodies often requires a specific antigenic sequence of a protein in order to get an efficient immune response and minimize cross-reactivity of antibodies. Larger proteins like GST (Glutathione-S-transferase) or MBP (maltose binding protein) as solubilizing fusion partners are frequently used to keep antigens soluble and immunize animals. This approach has the disadvantage that the immune response against the fusion partner leads to additional antibodies that need to be separated from the antigen-specific antibodies. For both classes of proteins mentioned above, a protocol has been developed and optimized using the human version of small ubiquitin-like modifier 3 (SUMO3) protein and its corresponding protease SenP2. This chapter describes the experimental steps for expression, purification, refolding, and cleavage that are applicable to both disulfide-bonded proteins with a defined structure and random protein fragments for

  12. Compensatory rebalancing of rice prolamins by production of recombinant prolamin/bioactive peptide fusion proteins within ER-derived protein bodies.

    Science.gov (United States)

    Takaiwa, Fumio; Yang, Lijun; Wakasa, Yuhya; Ozawa, Kenjiro

    2018-02-01

    Bioactive peptide was produced by fusion to rice prolamins in transgenic rice seeds. Their accumulation levels were affected by their deposition sites and by compensatory rebalancing between prolamins within PB-Is. Peptide immunotherapy using analogue peptide ligands (APLs) is one of promising treatments against autoimmune diseases. Use of seed storage protein as a fusion carrier is reasonable strategy for production of such small size bioactive peptides. In this study, to examine the efficacy of various rice prolamins deposited in ER-derived protein bodies (PB-Is), the APL12 from the Glucose-6-phosphate isomerase (GPI325-339) was expressed by fusion to four types of representative prolamins under the control of the individual native promoters. When the 14 and 16 kDa Cys-rich prolamins, which were localized in middle layer of PB-Is, were used for production of the APL12, they highly accumulated in transgenic rice seeds (~ 200 µg/grain). By contrast, fusion to the 10 and 13 kDa prolamins, which were localized in the core and outermost layer of PB-Is, resulted in lower levels of accumulation (~ 40 µg/grain). These results suggest that accumulation levels were highly affected by their deposition sites. Next, when different prolamin/APL12 fusion proteins were co-expressed to increase accumulation levels, they could not be increased so much as their expected additive levels. High accumulation of one type prolamin/APL12 led to reduction of other type(s) prolamin/APL12 to maintain the limited amounts of prolamins that can be deposited in PB-Is. Moreover, suppression of endogenous seed proteins by RNA interference also did not significantly enhance the accumulation levels of prolamin/APL12. These findings suggest that there may be compensatory rebalancing mechanism that controls the accumulation levels of prolamins deposited within PB-Is.

  13. Overproduction, purification and characterization of human interferon alpha2a-human serum albumin fusion protein produced in methilotropic yeast Pichia pastoris

    Science.gov (United States)

    Ningrum, R. A.; Santoso, A.; Herawati, N.

    2017-05-01

    Human interferon alpha2a (hIFNα2a) is a therapeutic protein that used in cancer and hepatitis B/C therapy. The main problem of using hIFNα-2a is its short elimination half life due to its low molecular weight. Development of higher molecular weight protein by albumin fusion technology is a rational strategy to solve the problem. In our previous research we constructed an open reading frame (ORF) encoding hIFNα2a-human serum albumin (HSA) fusion protein that expressed in Pichia pastoris (P. pastoris) protease deficient strain SMD1168. This research was performed to overproduce, purify and characterize the fusion protein. To overproduce the protein, cultivation was performed in buffered complex medium containing glyserol (BMGY) for 24 h and protein overproduction was applied in buffered complex medium containing methanol (BMMY) for 48 hours at 30°C. The fusion protein was purified by blue sepharose affinity chromatography. Molecular weight characterization by SDS PAGE corresponds with its theoretical size, 85 kDa. Western blot analysis demonstrated that the fusion protein was recognized by anti hIFNα2 and anti HSA monoclonal antibody as well. Amino acid sequence of the fusion protein was determined by LC MS/MS2 mass spectrometry with trypsin as proteolitic enzyme. There were three fragments that identified as hIFNα2a and seven fragments that identified as HSA. Total identified amino acids were 150 residues with 20% coverage from total residues. To conclude, hIFNα2a-HSA fusion protein was overproduced, purified and characterized. Characterization based on molecular weight, antibody recognition and amino acid sequence confirmed that the fusion protein has correct identity as theoretically thought.

  14. Two active molecular phenotypes of the tachykinin NK1 receptor revealed by G-protein fusions and mutagenesis.

    Science.gov (United States)

    Holst, B; Hastrup, H; Raffetseder, U; Martini, L; Schwartz, T W

    2001-06-08

    The NK1 neurokinin receptor presents two non-ideal binding phenomena, two-component binding curves for all agonists and significant differences between agonist affinity determined by homologous versus heterologous competition binding. Whole cell binding with fusion proteins constructed between either Galpha(s) or Galpha(q) and the NK1 receptor with a truncated tail, which secured non-promiscuous G-protein interaction, demonstrated monocomponent agonist binding closely corresponding to either of the two affinity states found in the wild-type receptor. High affinity binding of both substance P and neurokinin A was observed in the tail-truncated Galpha(s) fusion construct, whereas the lower affinity component was displayed by the tail-truncated Galpha(q) fusion. The elusive difference between the affinity determined in heterologous versus homologous binding assays for substance P and especially for neurokinin A was eliminated in the G-protein fusions. An NK1 receptor mutant with a single substitution at the extracellular end of TM-III-(F111S), which totally uncoupled the receptor from Galpha(s) signaling, showed binding properties that were monocomponent and otherwise very similar to those observed in the tail-truncated Galpha(q) fusion construct. Thus, the heterogenous pharmacological phenotype displayed by the NK1 receptor is a reflection of the occurrence of two active conformations or molecular phenotypes representing complexes with the Galpha(s) and Galpha(q) species, respectively. We propose that these molecular forms do not interchange readily, conceivably because of the occurrence of microdomains or "signal-transductosomes" within the cell membrane.

  15. A fusion protein strategy for soluble expression ofSteviaglycosyltransferase UGT76G1 inEscherichia coli.

    Science.gov (United States)

    Chen, Liangliang; Sun, Ping; Li, Yan; Yan, Ming; Xu, Lin; Chen, Kequan; Ouyang, Pingkai

    2017-12-01

    The UDP-glucosyltransferase UGT76G1 from Stevia rebaudiana converts stevioside to rebaudioside A via a one-step glycosylation reaction, which increases the amount of sweet-tasting rebaudioside A and decreases the amount of stevioside that has a bitter aftertaste. This enzyme could, therefore, conceivably be used to improve the organoleptic properties of steviol glycosides and offer a cost-effective preparation of high-purity rebaudioside A. Producing soluble enzymes by overexpression is a prerequisite for large-scale biocatalysis. However, most of the UGT76G1 overexpressed in Escherichia coli is in inclusion bodies. In this study, three N-terminal fusion partners, 3'-phosphoadenosine-5'-phosphatase (CysQ), 2-keto-3-deoxy-6-phosphogluconate aldolase (EDA) and N-utilisation substance A (NusA), were tested to improve UGT76G1 expression and solubility in E. coli . Compared with the fusion-free protein, the solubility of UGT76G1 was increased 40% by fusion with CysQ, and the glucosyltransferase activity of the crude extract was increased 82%. This successful CysQ fusion strategy could be applied to enhance the expression and solubility of other plant-derived glucosyltransferases and presumably other unrelated proteins in the popular, convenient and cost-effective E. coli host.

  16. Photoactivatable green fluorescent protein-based visualization and quantification of mitochondrial fusion and mitochondrial network complexity in living cells.

    Science.gov (United States)

    Karbowski, Mariusz; Cleland, Megan M; Roelofs, Brian A

    2014-01-01

    Technological improvements in microscopy and the development of mitochondria-specific imaging molecular tools have illuminated the dynamic rearrangements of these essential organelles. These rearrangements are mainly the result of two opposing processes: mitochondrial fusion and mitochondrial fission. Consistent with this, in addition to mitochondrial motility, these two processes are major factors determining the overall degree of continuity of the mitochondrial network, as well as the average size of mitochondria within the cell. In this chapter, we detail the use of advanced confocal microscopy and mitochondrial matrix-targeted photoactivatable green fluorescent protein (mito-PAGFP) for the investigation of mitochondrial dynamics. We focus on direct visualization and quantification of mitochondrial fusion and mitochondrial network complexity in living mammalian cells. These assays were instrumental in important recent discoveries within the field of mitochondrial biology, including the role of mitochondrial fusion in the activation of mitochondrial steps in apoptosis, participation of Bcl-2 family proteins in mitochondrial morphogenesis, and stress-induced mitochondrial hyperfusion. We present some basic directions that should be helpful in designing mito-PAGFP-based experiments. Furthermore, since analyses of mitochondrial fusion using mito-PAGFP-based assays rely on time-lapse imaging, critical parameters of time-lapse microscopy and cell preparation are also discussed.

  17. Expression of a fusion protein of human ciliary neurotrophic factor and soluble CNTF-receptor and identification of its activity.

    Science.gov (United States)

    Sun, Yi; Pia, März; Uwe, Otten; Ge, Ji-Guang; Stefan, Rose-John

    2003-01-01

    Ciliary neurotrophic factor (CNTF) has pleiotropic actions on many neuronal populations as well as on glia. Signal transduction by CNTF requires that it bind first to CNTF-R, permitting the recruitment of gp130 and LIF-R, forming a tripartite receptor complex. Cells that only express gp130 and LIF-R, but not CNTF-R are refractory to stimulation by CNTF. On many target cells CNTF only acts in the presence of its specific agonistic soluble receptors. We engineered a soluble fusion protein by linking the COOH-terminus of sCNTF-R to the NH2-terminus of CNTF. Recombinant CNTF/sCNTF-R fusion protein (Hyper-CNTF) was successfully expressed in COS-7 cells. The apparent molecular mass of the Hyper-CNTF protein was estimated from western blots to be 75 kDa. Proliferation assays of transfected BAF/3 cells in response to CNTF and Hyper-CNTF were used to verify the activity of the cytokines. The proliferative results confirmed that CNTF required homodimerization of the gp130, CNTF-R and LIF-R receptor subunit whereas Hyper-CNTF required heterodimerization of the gp130 and LIF-R receptor subunit. We concluded that the fusion protein Hyper-CNTF had superagonistic activity on target cells expressing gp130 and LIF-R, but lacking membrane-bound CNTF-R.

  18. Proteomics computational analyses suggest that the bornavirus glycoprotein is a class III viral fusion protein (γ penetrene

    Directory of Open Access Journals (Sweden)

    Garry Robert F

    2009-09-01

    Full Text Available Abstract Background Borna disease virus (BDV is the type member of the Bornaviridae, a family of viruses that induce often fatal neurological diseases in horses, sheep and other animals, and have been proposed to have roles in certain psychiatric diseases of humans. The BDV glycoprotein (G is an extensively glycosylated protein that migrates with an apparent molecular mass of 84,000 to 94,000 kilodaltons (kDa. BDV G is post-translationally cleaved by the cellular subtilisin-like protease furin into two subunits, a 41 kDa amino terminal protein GP1 and a 43 kDa carboxyl terminal protein GP2. Results Class III viral fusion proteins (VFP encoded by members of the Rhabdoviridae, Herpesviridae and Baculoviridae have an internal fusion domain comprised of beta sheets, other beta sheet domains, an extended alpha helical domain, a membrane proximal stem domain and a carboxyl terminal anchor. Proteomics computational analyses suggest that the structural/functional motifs that characterize class III VFP are located collinearly in BDV G. Structural models were established for BDV G based on the post-fusion structure of a prototypic class III VFP, vesicular stomatitis virus glycoprotein (VSV G. Conclusion These results suggest that G encoded by members of the Bornavirdae are class III VFPs (gamma-penetrenes.

  19. Expression, one-step purification, and immobilization of HaloTag(TM) fusion proteins on chloroalkane-functionalized magnetic beads.

    Science.gov (United States)

    Motejadded, Hassan; Kranz, Bertolt; Berensmeier, Sonja; Franzreb, Matthias; Altenbuchner, Josef

    2010-11-01

    The presented work introduces a novel method to immobilize enzymes either purified or directly out of a crude extract onto magnetic particles in the micrometer range. This method is based on the creation of a fusion protein consisting of the enzyme of choice and a mutant dehalogenase. The dehalogenase gene is commercially available from the company Promega under the name HaloTag(TM). When the fusion protein is contacted with magnetic beads having chemically synthesized, chloroalkane ligands on their surface, the dehalogenase and the ligand undergo a covalent coupling leading to stable and spatially defined immobilization. The principle was proved with a lipase fused to the HaloTag(TM) gene and magnetic poly(methyl)methacrylate beads as carriers. The solubility of the tagged lipase was strongly increased by fusion of the malE gene at the N-terminal end of the HaloTag(TM) lipase gene. This tripartite protein was purified on amylose resin and used for immobilization. About 13 µg protein could be immobilized per 1 mg of beads within a few minutes. Due to the defined binding site, no activity loss was observed in the course of the immobilization. The resulting enzyme carrier was tested with the same beads up to six times for lipase activity over a storage period of 36 days at 8 °C. No loss of activity was found during this time.

  20. Endoplasmic reticulum protein 29 (ERp29, a protein related to sperm maturation is involved in sperm-oocyte fusion in mouse

    Directory of Open Access Journals (Sweden)

    Zhu Yemin

    2010-02-01

    Full Text Available Abstract Background Sperm-oocyte fusion is a critical step in fertilization, which requires a series of proteins from both spermatozoa and oocyte to mediate membrane adhesion and subsequent fusion. A rat spermatozoa membrane protein is endoplasmic reticulum protein 29 (ERp29, which significantly increases on the sperm surface as well as in the cytoplasm of epididymal epithelia from caput to cauda as the sperm undergo epididymal maturation. Moreover, ERp29 facilitates viral infection via mediating membrane penetration. We determined if in addition to promoting sperm maturation ERp29 may also play a role in facilitating gamete fusion during the fertilization process. Methods Laser scanning confocal microscopy (LSCM and Western blot analysis were employed to probe for ERp29 protein in BALB/c mouse epididymal and acrosome-reacted spermatozoa. We prepared rabbit polyclonal antibodies against mouse recombinant ERp29 (rERp29 to characterize: 1 fertilization rate (FR; 2 fertilization index (FI; 3 sperm motility and 4 acrosome reaction (AR. Results Confocal microscopy indicated that ERp29 was partially localized at the sperm head of the epididymal caput as well as over the whole head and part of the principal piece of the tail region from the epididymal cauda. However, when the acrosome reacted, ERp29 remained in the equatorial and post-acrosomal regions of the sperm head, which is the initial site of sperm-oocyte membrane fusion. Such localization changes were confirmed based on the results of Western blot analysis. Furthermore, the antibodies against mouse rERp29 inhibited the spermatozoa from penetrating into the zona pellucida (ZP-free oocytes. The functional blocking antibodies reduced both mouse sperm-oocyte FR and FI at concentrations of 100 and 200 micro g/ml compared with pre-immunized rabbit IgG or with anti-mouse recombinant bactericidal/permeability-increasing protein (BPI, a sperm surface protein unrelated to sperm-oocyte fusion antibodies

  1. Homomultimerization of the reovirus p14 fusion-associated small transmembrane protein during transit through the ER-Golgi complex secretory pathway.

    Science.gov (United States)

    Corcoran, Jennifer A; Clancy, Eileen K; Duncan, Roy

    2011-01-01

    The reovirus fusion-associated small transmembrane (FAST) proteins are the smallest known viral membrane-fusion proteins. How these diminutive fusogens mediate cell-cell fusion and syncytium formation is unclear. Ongoing efforts are aimed at defining the roles of the FAST protein ecto-, endo- and transmembrane domains in the membrane-fusion reaction. We now provide direct evidence for homomultimer formation by the FAST proteins by using an anti-haemagglutinin (HA) mAb to co-precipitate the untagged p14 FAST protein from cells co-transfected with HA-tagged p14. Disrupting the intracellular endoplasmic reticulum-Golgi complex vesicle transport pathway prevented p14 homomultimer formation, while lower pH disrupted p14 multimers. The p14 endodomain or transmembrane domains are not required for multimer formation, which, along with the pH sensitivity and the distribution of histidine residues, suggests the 36 aa p14 ectodomain is a multimerization motif.

  2. Expression of proteins in Escherichia coli as fusions with maltose-binding protein to rescue non-expressed targets in a high-throughput protein-expression and purification pipeline

    International Nuclear Information System (INIS)

    Hewitt, Stephen N.; Choi, Ryan; Kelley, Angela; Crowther, Gregory J.; Napuli, Alberto J.; Van Voorhis, Wesley C.

    2011-01-01

    The rescue of protein-expression levels by cloning genes into MBP-fusion vector is described. Despite recent advances, the expression of heterologous proteins in Escherichia coli for crystallization remains a nontrivial challenge. The present study investigates the efficacy of maltose-binding protein (MBP) fusion as a general strategy for rescuing the expression of target proteins. From a group of sequence-verified clones with undetectable levels of protein expression in an E. coli T7 expression system, 95 clones representing 16 phylogenetically diverse organisms were selected for recloning into a chimeric expression vector with an N-terminal histidine-tagged MBP. PCR-amplified inserts were annealed into an identical ligation-independent cloning region in an MBP-fusion vector and were analyzed for expression and solubility by high-throughput nickel-affinity binding. This approach yielded detectable expression of 72% of the clones; soluble expression was visible in 62%. However, the solubility of most proteins was marginal to poor upon cleavage of the MBP tag. This study offers large-scale evidence that MBP can improve the soluble expression of previously non-expressing proteins from a variety of eukaryotic and prokaryotic organisms. While the behavior of the cleaved proteins was disappointing, further refinements in MBP tagging may permit the more widespread use of MBP-fusion proteins in crystallographic studies

  3. Coronavirus escape from heptad repeat 2 (HR2)-derived peptide entry inhibition as a result of mutations in the HR1 domain of the spike fusion protein

    NARCIS (Netherlands)

    Bosch, Berend Jan; Rossen, John W. A.; Bartelink, Willem; Zuurveen, Stephanie J.; de Haan, Cornelis A. M.; Duquerroy, Stephane; Boucher, Charles A. B.; Rottier, Peter J. M.

    Peptides based on heptad repeat (HR) domains of class I viral fusion proteins are considered promising antiviral drugs targeting virus cell entry. We have analyzed the evolution of the mouse hepatitis coronavirus during multiple passaging in the presence of an HR2-based fusion inhibitor.

  4. Clinical Applications of Phage-Derived sFvs and sFv Fusion Proteins

    Directory of Open Access Journals (Sweden)

    K. A. Chester

    2000-01-01

    Full Text Available Single chain Fv antibodies (sFvs have been produced from filamentous bacteriophage libraries obtained from immunised mice. MFE-23, the most characterised of these sFvs, is reactive with carcinoembryonic antigen (CEA, a glycoprotein that is highly expressed in colorectal adenocarcinomas. MFE-23 has been expressed in bacteria and purified in our laboratory for two clinical trials; a gamma camera imaging trial using 123I-MFE-23 and a radioimmunoguided surgery trial using 125I-MFE-23, where tumour deposits are detected by a hand-held probe during surgery. Both these trials show MFE-23 is safe and effective in localising tumour deposits in patients with cancer. We are now developing fusion proteins which use MFE-23 to deliver a therapeutic moiety; MFE-23::CPG2 targets the enzyme carboxypeptidase G2 (CPG2 for use in the ADEPT (antibody directed enzyme prodrug therapy system and MFE::TNFα aims to reduce sequestration and increase tumor concentrations of systemically administered TNFα.

  5. JAK inhibitors suppress t(8;21) fusion protein-induced leukemia

    Science.gov (United States)

    Lo, Miao-Chia; Peterson, Luke F.; Yan, Ming; Cong, Xiuli; Hickman, Justin H.; DeKelver, Russel C.; Niewerth, Denise; Zhang, Dong-Er

    2014-01-01

    Oncogenic mutations in components of the JAK/STAT pathway, including those in cytokine receptors and JAKs, lead to increased activity of downstream signaling and are frequently found in leukemia and other hematological disorders. Thus, small-molecule inhibitors of this pathway have been the focus of targeted therapy in these hematological diseases. We previously showed that t(8;21) fusion protein AML1-ETO and its alternatively spliced variant AML1-ETO9a (AE9a) enhance the JAK/STAT pathway via down-regulation of CD45, a negative regulator of this pathway. To investigate the therapeutic potential of targeting JAK/STAT in t(8;21) leukemia, we examined the effects of a JAK2-selective inhibitor TG101209 and a JAK1/2-selective inhibitor INCB18424 on t(8;21) leukemia cells. TG101209 and INCB18424 inhibited proliferation and promoted apoptosis of these cells. Furthermore, TG101209 treatment in AE9a leukemia mice reduced tumor burden and significantly prolonged survival. TG101209 also significantly impaired the leukemia-initiating potential of AE9a leukemia cells in secondary recipient mice. These results demonstrate the potential therapeutic efficacy of JAK inhibitors in treating t(8;21) AML. PMID:23812420

  6. Insect GDNF:TTC fusion protein improves delivery of GDNF to mouse CNS

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianhong; Chian, Ru-Ju; Ay, Ilknur; Kashi, Brenda B.; Celia, Samuel A.; Tamrazian, Eric [Cecil B. Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129 (United States); Pepinsky, R. Blake [BiogenIdec, Inc., 14 Cambridge Center, Cambridge, MA 02142 (United States); Fishman, Paul S. [Research Service, Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201 (United States); Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201 (United States); Brown, Robert H. [Cecil B. Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129 (United States); Francis, Jonathan W., E-mail: jwfrancisby@gmail.com [Cecil B. Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129 (United States)

    2009-12-18

    With a view toward improving delivery of exogenous glial cell line-derived neurotrophic factor (GDNF) to CNS motor neurons in vivo, we evaluated the bioavailability and pharmacological activity of a recombinant GDNF:tetanus toxin C-fragment fusion protein in mouse CNS. Following intramuscular injection, GDNF:TTC but not recombinant GDNF (rGDNF) produced strong GDNF immunostaining within ventral horn cells of the spinal cord. Intrathecal infusion of GDNF:TTC resulted in tissue concentrations of GDNF in lumbar spinal cord that were at least 150-fold higher than those in mice treated with rGDNF. While levels of immunoreactive choline acetyltransferase and GFR{alpha}-1 in lumbar cord were not altered significantly by intrathecal infusion of rGNDF, GDNF:TTC, or TTC, only rGDNF and GDNF:TTC caused significant weight loss following intracerebroventricular infusion. These studies indicate that insect cell-derived GDNF:TTC retains its bi-functional activity in mammalian CNS in vivo and improves delivery of GDNF to spinal cord following intramuscular- or intrathecal administration.

  7. Insect GDNF:TTC fusion protein improves delivery of GDNF to mouse CNS

    International Nuclear Information System (INIS)

    Li, Jianhong; Chian, Ru-Ju; Ay, Ilknur; Kashi, Brenda B.; Celia, Samuel A.; Tamrazian, Eric; Pepinsky, R. Blake; Fishman, Paul S.; Brown, Robert H.; Francis, Jonathan W.

    2009-01-01

    With a view toward improving delivery of exogenous glial cell line-derived neurotrophic factor (GDNF) to CNS motor neurons in vivo, we evaluated the bioavailability and pharmacological activity of a recombinant GDNF:tetanus toxin C-fragment fusion protein in mouse CNS. Following intramuscular injection, GDNF:TTC but not recombinant GDNF (rGDNF) produced strong GDNF immunostaining within ventral horn cells of the spinal cord. Intrathecal infusion of GDNF:TTC resulted in tissue concentrations of GDNF in lumbar spinal cord that were at least 150-fold higher than those in mice treated with rGDNF. While levels of immunoreactive choline acetyltransferase and GFRα-1 in lumbar cord were not altered significantly by intrathecal infusion of rGNDF, GDNF:TTC, or TTC, only rGDNF and GDNF:TTC caused significant weight loss following intracerebroventricular infusion. These studies indicate that insect cell-derived GDNF:TTC retains its bi-functional activity in mammalian CNS in vivo and improves delivery of GDNF to spinal cord following intramuscular- or intrathecal administration.

  8. Trypsin- and low pH-mediated fusogenicity of avian metapneumovirus fusion proteins is determined by residues at positions 100, 101 and 294.

    Science.gov (United States)

    Yun, Bingling; Guan, Xiaolu; Liu, Yongzhen; Gao, Yanni; Wang, Yongqiang; Qi, Xiaole; Cui, Hongyu; Liu, Changjun; Zhang, Yanping; Gao, Li; Li, Kai; Gao, Honglei; Gao, Yulong; Wang, Xiaomei

    2015-10-26

    Avian metapneumovirus (aMPV) and human metapneumovirus (hMPV) are members of the genus Metapneumovirus in the subfamily Pneumovirinae. Metapneumovirus fusion (F) protein mediates the fusion of host cells with the virus membrane for infection. Trypsin- and/or low pH-induced membrane fusion is a strain-dependent phenomenon for hMPV. Here, we demonstrated that three subtypes of aMPV (aMPV/A, aMPV/B, and aMPV/C) F proteins promoted cell-cell fusion in the absence of trypsin. Indeed, in the presence of trypsin, only aMPV/C F protein fusogenicity was enhanced. Mutagenesis of the amino acids at position 100 and/or 101, located at a putative cleavage region in aMPV F proteins, revealed that the trypsin-mediated fusogenicity of aMPV F proteins is regulated by the residues at positions 100 and 101. Moreover, we demonstrated that aMPV/A and aMPV/B F proteins mediated cell-cell fusion independent of low pH, whereas the aMPV/C F protein did not. Mutagenesis of the residue at position 294 in the aMPV/A, aMPV/B, and aMPV/C F proteins showed that 294G played a critical role in F protein-mediated fusion under low pH conditions. These findings on aMPV F protein-induced cell-cell fusion provide new insights into the molecular mechanisms underlying membrane fusion and pathogenesis of aMPV.

  9. Role for Homodimerization in Growth Deregulation by E2a Fusion Proteins

    Science.gov (United States)

    Bayly, Richard; LeBrun, David P.

    2000-01-01

    The oncogenic transcription factor E2a-Pbx1 is expressed in some cases of acute lymphoblastic leukemia as a result of chromosomal translocation 1;19. The early observation that E2a-Pbx1 incorporates transcriptional activation domains from E2a and a DNA-binding homeodomain from Pbx1 inspired a model in which E2a-Pbx1 promotes leukemogenic transformation of lymphoid progenitor cells through transcriptional induction of target genes defined by the Pbx1 portion of the molecule. However, the subsequent demonstration that the only known DNA-binding module on the molecule, the Pbx1 homeodomain, is dispensable for the induction of lymphoblastic lymphoma in transgenic mice called into question the contribution made by the Pbx1 portion. In this study, we have used a domain swap approach coupled with a fibroblast-based focus formation assay to evaluate further the requirement for PBX1-encoded peptide elements in growth deregulation by E2a-Pbx1. No impairment of focus formation was observed when the entire Pbx1 portion was replaced with DNA-binding/dimerization domains derived from yeast transcription factor GAL4 or GCN4. Furthermore, replacement of Pbx1 with tandem FKBP domains that mediate homodimerization in the presence of a synthetic ligand led to striking growth deregulation exclusively in the presence of the dimerizing agent. N-terminal elements encoded by E2A, including the AD1 transcriptional activation domain, were required for dimerization-induced focus formation. We conclude that transcriptional target genes defined by heterologous C-terminal DNA-binding modules are not required in growth deregulation by E2a fusion proteins. We speculate that interactions between N-terminal E2a elements and undefined proteins that could function as components of a transcriptional coactivator complex may be more important. PMID:10913162

  10. Optimized purification of a fusion protein by reversed-phase high performance liquid chromatography informed by the linear solvent strength model.

    Science.gov (United States)

    Falconer, Isaac B; Mant, Colin T; McKnight, C James; Vugmeyster, Liliya; Hodges, Robert

    2017-10-27

    Fusion protein systems are commonly used for expression of small proteins and peptides. An important criterion for a fusion protein system to be useful is the ability to separate the protein of interest from the tag. Additionally, because no protease cleaves fusion proteins with 100% efficiency, the ability to separate the desired peptide from any remaining uncleaved protein is also necessary. This is likely to be the more difficult task as at least a portion of the sequence of the fusion protein is identical to that of the protein of interest. When a high level of purity is required, gradient elution reversed-phase HPLC is frequently used as a final purification step. Shallow gradients are often advantageous for maximizing both the purity and yield of the final product; however, the relationship between relative retention times at shallow gradients and those at steeper gradients typically used for analytical HPLC are not always straightforward. In this work, we report reversed-phase HPLC results for the fusion protein system consisting of the N-terminal domain of ribosomal protein L9 (NTL9) and the 36-residue villin headpiece subdomain (HP36) linked by a recognition sequence for the protease factor Xa. This system represents an excellent example of the difficulties in purification that may arise from this unexpected elution behavior at shallow gradients. Additionally, we report on the sensitivity of this elution behavior to the concentration of the additive trifluoroacetic acid in the mobile phase and present optimized conditions for separating HP36 from the full fusion protein by reversed-phase HPLC using a shallow gradient. Finally, we suggest that these findings are relevant to the purification of other fusion protein systems, for which similar problems may arise, and support this suggestion using insights from the linear solvent strength model of gradient elution liquid chromatography. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Regulating gonad inhibition and vitellogenin/vitellin induction in Penaeus monodon using mature GIH fusion protein and polyclonal antisera.

    Science.gov (United States)

    S, Vrinda; C, Jasmin; K C, Sivakumar; Jose, Seena; Jose, Blessy; Philip, Rosamma; I S, Bright Singh

    2017-01-01

    Gonad inhibiting hormone (GIH), type II class of the CHH family neuropeptides, is released by the neurohaemal XO-SG complex of the eyestalk. The inhibitory function of GIH has a pivotal role in gonad development and reproduction. In this study, we report the expression and production of a thioredoxin-fused mature GIH protein (mf-PmGIH) of Penaeus monodon in a bacterial system and its use as antigen to raise polyclonal antiserum (anti-mf-PmGIH). The mature GIH gene of 237bp that codes for 79 amino acids, was cloned into the Escherichia coli thioredoxin gene fusion expression system. The expression vector construct (mf-PmGIH+pEt32a+) upon induction produced 32.16kDa mature GIH fusion protein (mf-PmGIH)·The purified fusion protein was used as exogenous GIH and as antigen to raise polyclonal antisera. The fusion protein when injected into juvenile shrimp significantly reduced vitellogenin/vitellin levels by 31.55% within 72h in comparison to the controls showing the gonad inhibiting property. Vitellogenin/vitellin levels were significantly induced by 74.10% within 6h when polyclonal antiserum (anti-mf-PmGIH - 1:500) was injected in P. monodon. Anti-mf-PmGIH immunolocalized GIH producing neurosecretory cells in the eyestalk of P. monodon. The present manuscript reports an innovative means of gonad inhibition and vitellogenin/vitellin induction with thioredoxin fused GIH and antisera developed. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Bactericidal Effects of a Fusion Protein of Llama Heavy-Chain Antibodies Coupled to Glucose Oxidase on Oral Bacteria

    OpenAIRE

    Szynol, A.; de Soet, J. J.; Sieben-van Tuyl, E.; Bos, J. W.; Frenken, L. G.

    2004-01-01

    Enzymes such as lactoperoxidase and glucose oxidase (GOx) are used as antimicrobial agents in oral care products. Their low specificities and substantiveness can be reduced by covalent coupling of antimicrobial molecules to antibodies. Variable domains (VHH) derived from llama heavy-chain antibodies are particularly suited for such an approach. The antibodies are composed solely of heavy-chain dimers; therefore, production of active fusion proteins by using molecular biology-based techniques ...

  13. Zipping into fusion

    NARCIS (Netherlands)

    Zheng, Tingting

    2014-01-01

    Fusion of lipid bilayers in cells facilitates the active transport of chemicals. Non-viral membrane fusion is regulated by a cascade of proteins as the process is highly regulated both in space and time. In eukaryotic cells, the so-called SNARE protein complex is at the heart of fusion. However,

  14. Chemoattractant-controlled accumulation of coronin at the leading edge of Dictyostelium cells monitored using a green fluorescent protein-coronin fusion protein.

    Science.gov (United States)

    Gerisch, G; Albrecht, R; Heizer, C; Hodgkinson, S; Maniak, M

    1995-11-01

    The highly motile cells of Dictyostelium discoideum rapidly remodel their actin filament system when they change their direction of locomotion either spontaneously or in response to chemoattractant. Coronin is a cytoplasmic actin-associated protein that accumulates at the coritcal sites of moving cells and contributes to the dynamics of the actin system. It is a member of the WD-repeat family of proteins and is known to interact with actin-myosin complexes. In coronin null mutants, cell locomotion is slowed down and cytokinesis is impaired. We have visualized the redistribution of coronin by fluorescence imaging of motile cells that have been transfected with an expression plasmid containing the coding sequence of coronin fused to the sequence encoding the green fluorescent protein (GFP). This coronin-GFP fusion protein (GFP). This coronin-GFP fusion protein transiently accumulates in the front regions of growth-phase cells, reflecting the changing positions of leading edges and the competition between them. During the aggregation stage, local accumulation of coronin-GFP is biased by chemotactic orientation of the cells in gradients of cAMP. The impairment of cell motility in coronin null mutants shows that coronin has an important function at the front region of the cells. The mutant cells are distinguished by the formation of extended particle-free zones at their front regions, from where pseudopods often break out as blebs. Cytochalasin A reduces the size of these zones, indicating that actin filaments prevent entry of the particles. These data demonstrate that coronin is reversibly recruited from the cytoplasm and is incorporated into the actin network of a nascent leading edge, where it participates in the reorganization of the cytoskeleton. Monitoring the dynamics of protein assembly using GFP fusion proteins and fluorescence microscopy promises to be a generally applicable method for studying the dynamics of cytoskeletal proteins in moving and dividing cells.

  15. In-silico determination of insecticidal potential of Vip3Aa-Cry1Ac fusion protein against Lepidopteran targets using molecular docking

    Directory of Open Access Journals (Sweden)

    Aftab eAhmad

    2015-12-01

    Full Text Available Study and research of Bt (Bacillus thuringiensis transgenic plants have opened new ways to combat insect pests. Over the decades, however, insect pests, especially the Lepidopteran, have developed tolerance against Bt delta-endotoxins. Such issues can be addressed through the development of novel toxins with greater toxicity and affinity against a broad range of insect receptors. In this computational study, functional domains of Bacillus thuringiensis crystal delta-endotoxin (Cry1Ac insecticidal protein and vegetative insecticidal protein (Vip3Aa have been fused to develop a broad-range Vip3Aa-Cry1Ac fusion protein. Cry1Ac and Vip3Aa are non-homologous insecticidal proteins possessing receptors against different targets within the midgut of insects. The insecticidal proteins were fused to broaden the insecticidal activity. Molecular docking analysis of the fusion protein against aminopeptidase-N (APN and cadherin receptors of five Lepidopteran insects (Agrotis ipsilon, Helicoverpa armigera, Pectinophora gossypiella, Spodoptera exigua and Spodoptera litura revealed that the Ser290, Ser293, Leu337, Thr340 and Arg437 residues of the fusion protein are involved in the interaction with insect receptors. The Helicoverpa armigera cadherin receptor, however, showed no interaction, which might be due to either loss or burial of interactive residues inside the fusion protein. These findings revealed that the Vip3Aa-Cry1Ac fusion protein has a strong affinity against Lepidopteran insect receptors and hence has a potential to be an efficient broad-range insecticidal protein.

  16. Characterization of EBV gB indicates properties of both class I and class II viral fusion proteins

    International Nuclear Information System (INIS)

    Backovic, Marija; Leser, George P.; Lamb, Robert A.; Longnecker, Richard; Jardetzky, Theodore S.

    2007-01-01

    To gain insight into Epstein-Barr virus (EBV) glycoprotein B (gB), recombinant, secreted variants were generated. The role of putative transmembrane regions, the proteolytic processing and the oligomerization state of the gB variants were investigated. Constructs containing 2 of 3 C-terminal hydrophobic regions were secreted, indicating that these do not act as transmembrane anchors. The efficiency of cleavage of the gB furin site was found to depend on the nature of C-terminus. All of the gB constructs formed rosette structures reminiscent of the postfusion aggregates formed by other viral fusion proteins. However, substitution of putative fusion loop residues, WY 112-113 and WLIY 193-196 , with less hydrophobic amino acids from HSV-1 gB, produced trimeric protein and abrogated the ability of the EBV gB ectodomains to form rosettes. These data demonstrate biochemical features of EBV gB that are characteristic of other class I and class II viral fusion proteins, but not of HSV-1 gB

  17. Phosphatidylinositol-3-kinase-dependent phosphorylation of SLP-76 by the lymphoma-associated ITK-SYK fusion-protein

    International Nuclear Information System (INIS)

    Hussain, Alamdar; Faryal, Rani; Nore, Beston F.; Mohamed, Abdalla J.; Smith, C.I. Edvard

    2009-01-01

    Recurrent chromosomal translocations have long been implicated in various types of lymphomas and other malignancies. Novel recurrent t(5;9)(q33;q22) has been recently discovered in un-specified peripheral T-cell lymphoma. To elucidate the role of this translocation, the corresponding fusion construct encoding the N-terminal portion of the ITK kinase and the C-terminal catalytic region of the SYK kinase was generated. We herein show that the ITK-SYK fusion-protein is constitutively active. Moreover, we demonstrate that ITK-SYK is phosphorylated on key tyrosine residues and is capable of potently phosphorylating the related adapter proteins BLNK and SLP-76. In transiently transfected cells, SYK was phosphorylated at Y352 but not detectably at the activation-loop tyrosines Y525/Y526. In contrast, ITK-SYK was phosphorylated both at Y212 and the activation-loop tyrosines Y385/Y386, corresponding to Y352 and Y525/Y526 in SYK, respectively. In resting primary lymphocytes, ITK-SYK predominantly localizes to the cell surface. In addition, we demonstrate that following stimulation, the ITK-SYK fusion-protein in cell lines translocates to the cell membrane and, moreover, that this phenomenon as well as SLP-76 phosphorylation are blocked upon phosphatidylinositol-3-kinase (PI3-kinase) inhibition.

  18. The fusion protein of wild-type canine distemper virus is a major determinant of persistent infection

    International Nuclear Information System (INIS)

    Plattet, Philippe; Rivals, Jean-Paul; Zuber, BenoIt; Brunner, Jean-Marc; Zurbriggen, Andreas; Wittek, Riccardo

    2005-01-01

    The wild-type A75/17 canine distemper virus (CDV) strain induces a persistent infection in the central nervous system but infects cell lines very inefficiently. In contrast, the genetically more distant Onderstepoort CDV vaccine strain (OP-CDV) induces extensive syncytia formation. Here, we investigated the roles of wild-type fusion (F WT ) and attachment (H WT ) proteins in Vero cells expressing, or not, the canine SLAM receptor by transfection experiments and by studying recombinants viruses expressing different combinations of wild-type and OP-CDV glycoproteins. We show that low fusogenicity is not due to a defect of the envelope proteins to reach the cell surface and that H WT determines persistent infection in a receptor-dependent manner, emphasizing the role of SLAM as a potent enhancer of fusogenicity. However, importantly, F WT reduced cell-to-cell fusion independently of the cell surface receptor, thus demonstrating that the fusion protein of the neurovirulent A75/17-CDV strain plays a key role in determining persistent infection

  19. Protective effects of a bacterially expressed NIF-KGF fusion protein against bleomycin-induced acute lung injury in mice.

    Science.gov (United States)

    Li, Xinping; Li, Shengli; Zhang, Miaotao; Li, Xiukun; Zhang, Xiaoming; Zhang, Wenlong; Li, Chuanghong

    2010-08-01

    Current evidence suggests that the keratinocyte growth factor (KGF) and the polymorphonuclear leukocyte may play key roles in the development of lung fibrosis. Here we describe the construction, expression, purification, and identification of a novel NIF (neutrophil inhibitory factor)-KGF mutant fusion protein (NKM). The fusion gene was ligated via a flexible octapeptide hinge and expressed as an insoluble protein in Escherichia coli BL21 (DE3). The fusion protein retained the activities of KGF and NIF, as it inhibited both fibroblast proliferation and leukocyte adhesion. Next, the effects of NKM on bleomycin-induced lung fibrosis in mice were examined. The mice were divided into the following four groups: (i) saline group; (ii) bleomycin group (instilled with 5 mg/kg bleomycin intratracheally); (iii) bleomycin plus dexamethasone (Dex) group (Dex was given intraperitoneally (i.p.) at 1 mg/kg/day 2 days prior to bleomycin instillation and daily after bleomycin instillation until the end of the treatment); and (iv) bleomycin plus NKM group (NKM was given i.p. at 2 mg/kg/day using the same protocol as the Dex group). NKM significantly improved the survival rates of mice exposed to bleomycin. The marked morphological changes and increased hydroxyproline levels resulted from the instillation of bleomycin (on Day 17) in the lungs were significantly inhibited by NKM. These results revealed that NKM can attenuate bleomycin-induced lung fibrosis, suggesting that NKM could be used to prevent bleomycin-induced lung damage or other interstitial pulmonary fibrosis.

  20. Fusion protein-based biofilm fabrication composed of recombinant azurin-myoglobin for dual-level biomemory application

    Science.gov (United States)

    Lee, Taek; Chung, Yong-Ho; Yoon, Jinho; Min, Junhong; Choi, Jeong-Woo

    2014-11-01

    In the present study, a fusion protein-based biofilm composed of a recombinant azurin-myoglobin (Azu-Myo) has been developed and confirmed its original electrochemical property for dual-level biomemory device application. For this purpose, the azurin was modified with cysteine residues for direct immobilization and conjugation. Then, the recombinant azurin was conjugated with the myoglobin via a sulfo-SMCC bifunctional linker using the chemical ligation method (CLM). The SDS-PAGE and UV-vis spectroscopy were performed to examine the fusion protein conjugates. The prepared Azu-Myo fusion protein was self-assembled onto Au substrate for the biofilm fabrication. Then, the atomic force microscopy (AFM) was used to confirm the immobilization and the surface-enhanced Raman spectroscopy (SERS) was carried out to the surface analysis. Also, the cyclic voltammetry (CV) was carried out to observe an electrochemical property of fabricated biofilm. As a result, the two pair of redox potential values was obtained for dual-level biomemory device application. Then, the dual-level biomemory function was verified by the multi-potential chronoamperometry (MPCA). The results indicate a new fabrication method and material combination for advances in bioelectronic device development.

  1. Recombinant fusion proteins TAT-Mu, Mu and Mu-Mu mediate efficient non-viral gene delivery.

    Science.gov (United States)

    Rajagopalan, Rukkumani; Xavier, Jennifer; Rangaraj, Nandini; Rao, Nalam Madhusudhana; Gopal, Vijaya

    2007-04-01

    The inherent ability of certain peptides or proteins of viral, prokaryotic and eukaryotic origin to bind DNA was used to generate novel peptide-based DNA delivery protocols. We have developed a recombinant approach to make fusion proteins with motifs for DNA-binding ability, Mu and membrane transduction domains, TAT, and tested them for their DNA-binding, uptake and transfection efficiencies. In one of the constructs, the recombinant plasmid was designed to encode the Mu moiety of sequence MRRAHHRRRRASHRRMRGG in-frame with TAT of sequence YGRKKRRQRRR to generate TAT-Mu, while the other two constructs, Mu and Mu-Mu, harbor a single copy or two copies of the Mu moiety. Recombinant his-tag fusion proteins TAT-Mu, Mu and Mu-Mu were purified by overexpression of plasmid constructs using cobalt-based affinity resins. The peptides were characterized for their size and interaction with DNA, complexed with plasmid pCMVbeta-gal, and shown to transfect MCF-7, COS and CHOK-1 cells efficiently. Recombinant fusion proteins TAT-Mu, Mu and Mu-Mu were cloned and overexpressed in BL21(DE3)pLysS with greater than 95% purity. The molecular weight of TAT-Mu was determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to be 11.34 kDa while those of Mu and Mu-Mu were 7.78 and 9.83 kDa, respectively. Live uptake analysis of TAT-Mu, Mu and Mu-Mu as DP (DNA+peptide) or DPL (DNA+peptide+lipid) complexes into MCF-7 cells, followed by immunostaining and laser scanning confocal microscopy, demonstrated that the complexes are internalized very efficiently and localized in the nucleus. DNA:peptide complexes (DP) transfect MCF-7, COS and CHOK-1 cells. The addition of cationic liposomes enhances the uptake of the ternary complexes (DPL) further and also brings about 3-7-fold enhancement in reporter gene expression compared to DP alone. Recombinant proteins that are heterologous fusions, having DNA-binding domains and nuclear localization epitopes

  2. A recombinant fusion protein containing a spider toxin specific for the insect voltage-gated sodium ion channel shows oral toxicity towards insects of different orders

    Science.gov (United States)

    Yang, Sheng; Pyati, Prashant; Fitches, Elaine; Gatehouse, John A.

    2014-01-01

    Recombinant fusion protein technology allows specific insecticidal protein and peptide toxins to display activity in orally-delivered biopesticides. The spider venom peptide δ-amaurobitoxin-PI1a, which targets insect voltage-gated sodium channels, was fused to the “carrier” snowdrop lectin (GNA) to confer oral toxicity. The toxin itself (PI1a) and an amaurobitoxin/GNA fusion protein (PI1a/GNA) were produced using the yeast Pichia pastoris as expression host. Although both proteins caused mortality when injected into cabbage moth (Mamestra brassicae) larvae, the PI1a/GNA fusion was approximately 6 times as effective as recombinant PI1a on a molar basis. PI1a alone was not orally active against cabbage moth larvae, but a single 30 μg dose of the PI1a/GNA fusion protein caused 100% larval mortality within 6 days when fed to 3rd instar larvae, and caused significant reductions in survival, growth and feeding in 4th – 6th instar larvae. Transport of fusion protein from gut contents to the haemolymph of cabbage moth larvae, and binding to the nerve chord, was shown by Western blotting. The PI1a/GNA fusion protein also caused mortality when delivered orally to dipteran (Musca domestica; housefly) and hemipteran (Acyrthosiphon pisum; pea aphid) insects, making it a promising candidate for development as a biopesticide. PMID:24486516

  3. Expression in E. coli and purification of the fibrillogenic fusion proteins TTR-sfGFP and β2M-sfGFP.

    Science.gov (United States)

    Solovyov, K V; Polyakov, D S; Grudinina, N A; Egorov, V V; Morozova, I V; Aleynikova, T D; Shavlovsky, M M

    2011-01-01

    The possibility of obtaining recombinant fibrillogenic fusion proteins such as transthyretin (TTR) and β2-microglobulin (β2M) with a superfolder green fluorescent protein (sfGFP) was studied. According to the literature data, sfGFP is resistant to denaturating influences, does not aggregate during renaturation, possesses improved kinetic characteristics of folding, and folds well when fused to different polypeptides. The corresponding DNA constructs for expression in Escherichia coli were created. It could be shown that during expression of these constructs in E. coli, soluble forms of the fusion proteins are synthesized. Efficient isolation of the fusion proteins was performed with the help of nickel-affinity chromatography. For this purpose a polyhistidine sequence (6-His-tag) was incorporated into the C-terminus of the sfGFP. We could show that the purified fusion proteins contained full-size sequences of the most amyloidogenic TTR variant, TTR(L55P) and β2M, and also sfGFP possessing fluorescent properties. In the course of fibrillogenesis both fusion proteins demonstrated their ability to form fibrils that were clearly detectable by atomic force microscopy. Furthermore, with the help of confocal microscopy we were able to reveal structures (exhibiting fluorescence) that are formed during fibrillogenesis. Thus, the use of sfGFP has made it possible to avoid formation of inclusion bodies (IB) during the synthesis of recombinant fusion proteins and to obtain soluble forms of TTR(L55P) and β2M that are suitable for further studies.

  4. Cyst-Like Osteolytic Formations in Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) Augmented Sheep Spinal Fusion.

    Science.gov (United States)

    Pan, Hsin Chuan; Lee, Soonchul; Ting, Kang; Shen, Jia; Wang, Chenchao; Nguyen, Alan; Berthiaume, Emily A; Zara, Janette N; Turner, A Simon; Seim, Howard B; Kwak, Jin Hee; Zhang, Xinli; Soo, Chia

    2017-07-01

    Multiple case reports using recombinant human bone morphogenetic protein-2 (rhBMP-2) have reported complications. However, the local adverse effects of rhBMP-2 application are not well documented. In this report we show that, in addition to promoting lumbar spinal fusion through potent osteogenic effects, rhBMP-2 augmentation promotes local cyst-like osteolytic formations in sheep trabecular bones that have undergone anterior lumbar interbody fusion. Three months after operation, conventional computed tomography showed that the trabecular bones of the rhBMP-2 application groups could fuse, whereas no fusion was observed in the control group. Micro-computed tomography analysis revealed that the core implant area's bone volume fraction and bone mineral density increased proportionately with rhBMP-2 dose. Multiple cyst-like bone voids were observed in peri-implant areas when using rhBMP-2 applications, and these sites showed significant bone mineral density decreases in relation to the unaffected regions. Biomechanically, these areas decreased in strength by 32% in comparison with noncystic areas. Histologically, rhBMP-2-affected void sites had an increased amount of fatty marrow, thinner trabecular bones, and significantly more adiponectin- and cathepsin K-positive cells. Despite promoting successful fusion, rhBMP-2 use in clinical applications may result in local adverse structural alterations and compromised biomechanical changes to the bone. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  5. Amino acid changes within the E protein hinge region that affect dengue virus type 2 infectivity and fusion

    International Nuclear Information System (INIS)

    Butrapet, Siritorn; Childers, Thomas; Moss, Kelley J.; Erb, Steven M.; Luy, Betty E.; Calvert, Amanda E.; Blair, Carol D.; Roehrig, John T.; Huang, Claire Y.-H.

    2011-01-01

    Fifteen mutant dengue viruses were engineered and used to identify AAs in the molecular hinge of the envelope protein that are critical to viral infection. Substitutions at Q52, A54, or E133 reduced infectivity in mammalian cells and altered the pH threshold of fusion. Mutations at F193, G266, I270, or G281 affected viral replication in mammalian and mosquito cells, but only I270W had reduced fusion activity. T280Y affected the pH threshold for fusion and reduced replication in C6/36 cells. Three different mutations at L135 were lethal in mammalian cells. Among them, L135G abrogated fusion and reduced replication in C6/36 cells, but only slightly reduced the mosquito infection rate. Conversely, L135W replicated well in C6/36 cells, but had the lowest mosquito infection rate. Possible interactions between hinge residues 52 and 277, or among 53, 135, 170, 186, 265, and 276 required for hinge function were discovered by sequence analysis to identify compensatory mutations.

  6. High expression of fusion proteins consisting of a single-chain variable fragment antibody against a tumor-associated antigen and interleukin-2 in Escherichia coli.

    Science.gov (United States)

    Napathorn, Suchada Chanprateep; Kuroki, Motomu; Kuroki, Masahide

    2014-08-01

    The aim of this study was to establish a strategy for high-level production of single-chain variable fragment (scFv) antibodies fused with interleukin-2 (IL-2) in Escherichia coli. We constructed two fusion sequences consisting of a scFv gene derived from a mouse monoclonal antibody against a tumor-associated antigen (MK-1) and human Interleukin-2(IL-2) gene, ligated the fusions into pET15b and transformed into three different E. coli strains. The effects of temperature, isopropyl-β-D-thiogalactopyranoside (IPTG) concentration and duration of IPTG induction were investigated. Employing E. coli strain Rosetta-gami B, which has an oxidizing cytoplasm that facilitates cytoplasmic disulfide bond formation, improved the level of soluble protein expression. Under optimal conditions, the highest levels of fusion protein expression and high percentages of the proteins were found in their soluble form. Specifically, 89.29% (0.28 g/l) of one fusion protein was soluble after a 10-h induction and 84.61% (0.26 g/l) of the other fusion protein was soluble after a separate 10-h induction. When analyzed by enzyme-linked immunosorbent assay, the partially-purified fusion proteins retained a specific binding activity to the cell lysate of Chinese hamster ovary (CHO) cells expressing MK-1. Taken together, the methods described herein permit the production of substantial amounts of the fusion proteins for conducting functional studies on the biological role of these fusion proteins. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  7. The immunogenicity of fusion protein linking the carboxyl terminus of the B subunit of Shiga toxin 2 to the B subunit of E. coli heat-labile enterotoxin.

    Science.gov (United States)

    Ran, Xue Qin; Wang, Hong Zhen; Liu, Jin Juan; Li, Sheng; Wang, Jia Fu

    2008-02-05

    To augment the immunogenicity of the subunit B of Shiga toxin (Stx2e B) produced by Escherichia coli and protect piglets from edema disease in china, a fusion gene was constructed consisting of Stx2e B genetically linked at the N-terminus of the B subunit of heat-labile enterotoxin (LTB) in a translational fusion. After being induced with IPTG, the expressed fusion protein of Stx2e B-LTB was about 8.8% of total proteins, approximately 13 microg/ml of the bacteria culture. The Stx2e B-LTB fusion protein was found to be nontoxic to Vero cells at the dose higher than 1 microg/ml and to mice less than 100 microg/ml. Antibody titer against the fusion protein Stx2e B-LTB was 1:76,800, much higher than that of the recombinant Stx2e B protein (1:12,800) alone. All of the mice immunized with the Stx2e B-LTB fusion protein survived when challenged with a lethal dose (LD) of Stx2e toxin. The results showed that the poor immunogenicity of Stx2e B was overcome by conjugating the stx2e B to ltB. The immunogenicity of the constructed fusion protein Stx2e B-LTB in the present study was highly qualified to protect animals against Shiga toxin produced from Shiga toxin-producing Escherichia coli (STEC). The fusion protein of Stx2e B-LTB could be a candidate for a vaccine against edema disease and post-weaning diarrhea simultaneously in piglets.

  8. Characterization of Thermobifida fusca Cutinase-Carbohydrate-Binding Module Fusion Proteins and Their Potential Application in Bioscouring▿ †

    Science.gov (United States)

    Zhang, Yao; Chen, Sheng; Xu, Meng; Cavoco-Paulo, Artur; Wu, Jing; Chen, Jian

    2010-01-01

    Cutinase from Thermobifida fusca is thermally stable and has potential application in the bioscouring of cotton in the textile industry. In the present study, the carbohydrate-binding modules (CBMs) from T. fusca cellulase Cel6A (CBMCel6A) and Cellulomonas fimi cellulase CenA (CBMCenA) were fused, separately, to the carboxyl terminus of T. fusca cutinase. Both fusion enzymes, cutinase-CBMCel6A and cutinase-CBMCenA, were expressed in Escherichia coli and purified to homogeneity. Enzyme characterization showed that both displayed similar catalytic properties and pH stabilities in response to T. fusca cutinase. In addition, both fusion proteins displayed an activity half-life of 53 h at their optimal temperature of 50°C. Compared to T. fusca cutinase, in the absence of pectinase, the binding activity on cotton fiber was enhanced by 2% for cutinase-CBMCel6A and by 28% for cutinase-CBMCenA, whereas in the presence of pectinase, the binding activity was enhanced by 40% for the former and 45% for the latter. Notably, a dramatic increase of up to 3-fold was observed in the amount of released fatty acids from cotton fiber by both cutinase-CBM fusion proteins when acting in concert with pectinase. This is the first report of improving the scouring efficiency of cutinase by fusing it with CBM. The improvement in activity and the strong synergistic effect between the fusion proteins and pectinase suggest that they may have better applications in textile bioscouring than the native cutinase. PMID:20729325

  9. Acute epidural lipedema: a novel entity and potential complication of bone morphogenetic protein use in lumbar spine fusion.

    Science.gov (United States)

    Merrick, Michael T; Hamilton, Kendall D; Russo, Scott S

    2013-10-01

    Bone morphogenetic proteins (BMPs) induce osteogenesis, making them useful for decreasing time to union and increasing union rates. Although the advantages of BMP-2 as a substitute for iliac crest graft have been elucidated, less is known about the safety profile and adverse events linked to their use in spinal fusion. An accumulation of reactive edema in the epidural fat may lead to neural compression and significant morbidity after lumbar spinal fusion. Bone morphogenetic protein has never been implicated as a cause of spinal epidural lipedema. We report on a case of rapid accumulation of edematous adipose tissue in the epidural space after lumbar spine decompression and fusion with bone morphogenic protein. Case report. The patient was a 45-year-old woman with chronic back pain, worsening bilateral L5 radiculopathy, and degenerative disc disease. Surgery consisting of a one-level transpedicular decompression, transforaminal lumbar interbody fusion, and posterolateral fusion was performed using BMP-2 as an adjunct for arthrodesis. Two days postoperatively, the patient developed progressive cauda equina syndrome. Lumbar magnetic resonance imaging revealed edematous epidural fat extending above the initial laminectomy, compromising the spinal canal, and compressing the thecal sac. Emergent laminectomies at L3, L4, and L5 were performed, and intraoperative pathology revealed edematous epidural adipose tissue. The patient's cauda equina syndrome resolved after spinal decompression and the removal of epidural fat. Final cultures were negative for infection, and histology report yielded an accumulation of edematous fibroadipose tissue. We present a case of rapid accumulation of edematous adipose tissue causing cauda equina syndrome after a lumbar decompression and fusion surgery. The acute nature and extensive development of the lipedema presented in this case indicate an intense inflammatory reaction. We hypothesize that there may be a link between the use of BMP-2

  10. Antibody glycosylation and its impact on the pharmacokinetics and pharmacodynamics of monoclonal antibodies and Fc-fusion proteins.

    Science.gov (United States)

    Liu, Liming

    2015-06-01

    Understanding the impact of glycosylation and keeping a close control on glycosylation of product candidates are required for both novel and biosimilar monoclonal antibodies (mAbs) and Fc-fusion protein development to ensure proper safety and efficacy profiles. Most therapeutic mAbs are of IgG class and contain a glycosylation site in the Fc region at amino acid position 297 and, in some cases, in the Fab region. For Fc-fusion proteins, glycosylation also frequently occurs in the fusion partners. Depending on the expression host, glycosylation patterns in mAb or Fc-fusions can be significantly different, thus significantly impacting the pharmacokinetics (PK) and pharmacodynamics (PD) of mAbs. Glycans that have a major impact on PK and PD of mAb or Fc-fusion proteins include mannose, sialic acids, fucose (Fuc), and galactose (Gal). Mannosylated glycans can impact the PK of the molecule, leading to reduced exposure and potentially lower efficacy. The level of sialic acid, N-acetylneuraminic acid (NANA), can also have a significant impact on the PK of Fc-fusion molecules. Core Fuc in the glycan structure reduces IgG antibody binding to IgG Fc receptor IIIa relative to IgG lacking Fuc, resulting in decreased antibody-dependent cell-mediated cytotoxicity (ADCC) activities. Glycoengineered Chinese hamster ovary (CHO) expression systems can produce afucosylated mAbs that have increased ADCC activities. Terminal Gal in a mAb is important in the complement-dependent cytotoxicity (CDC) in that lower levels of Gal reduce CDC activity. Glycans can also have impacts on the safety of mAb. mAbs produced in murine myeloma cells such as NS0 and SP2/0 contain glycans such as Galα1-3Galβ1-4N-acetylglucosamine-R and N-glycolylneuraminic acid (NGNA) that are not naturally present in humans and can be immunogenic when used as therapeutics. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  11. Induction of insolubility by herpes simplex virus VP22 precludes intercellular trafficking of N-terminal Apoptin-VP22 fusion proteins

    NARCIS (Netherlands)

    Rutjes, Saskia A.; Bosma, Piter J.; Rohn, Jennifer L.; Noteborn, Mathieu H. M.; Wesseling, John G.

    2003-01-01

    The herpes simplex virus protein VP22 has the intriguing ability to deliver proteins from an expressing cell to neighboring cells. Fusion of VP22 to Apoptin, a protein that induces apoptosis in tumor cells but not in normal cells, might enhance the delivery of Apoptin. To analyze this hypothesis two

  12. ACCUMULATION OF RECOMBINANT FUSION PROTEIN – SECRETORY ANALOG OF Ag85B AND ESAT6 MYCOBACTERIUM TUBERCULOSIS PROTEINS – IN TRANSGENIC Lemna minor L. PLANTS

    Directory of Open Access Journals (Sweden)

    A.A.Peterson

    2015-10-01

    Full Text Available Determination of the presence of the recombinant fusion protein (ESAT6-Ag85B(ΔTMD-6His and its accumulation level in duckweed plants (Lemna minor L. was the aim of the research. ESAT6 and Ag85B are secretory proteins of Mycobacterium tuberculosis and are considered as potential candidates for development of new vaccine against tuberculosis (TB. Transgenic duckweed plants were obtained previously by Agrobacterium rhizogenes-mediated transformation and possessed fusion gene sequence esxA-fbpBΔTMD. Specific polyclonal antibodies were produced in immunized mice to identify levels of accumulation of TB antigens in plants. Recombinant antigen used for mice immunization was obtained in our laboratory by expression in E. coli. Western blot analysis revealed the recombinant tuberculosis antigen ESAT6-Ag85B(ΔTMD-6His in extracts from transgenic L. minor plants. The level of accumulation of the protein corresponds to 0.4-0.5 µg protein per 1 g of fresh weight of plant. Additionally, the accumulation of recombinant protein was investigated in lyophilized transgenic plants after 1.5 year storage. Duckweed plants accumulating a recombinant analogue of M. tuberculosis secretory proteins can be used for development of plant-based edible vaccines.

  13. Characterization of the Neurospora crassa cell fusion proteins, HAM-6, HAM-7, HAM-8, HAM-9, HAM-10, AMPH-1 and WHI-2.

    Directory of Open Access Journals (Sweden)

    Ci Fu

    Full Text Available Intercellular communication of vegetative cells and their subsequent cell fusion is vital for different aspects of growth, fitness, and differentiation of filamentous fungi. Cell fusion between germinating spores is important for early colony establishment, while hyphal fusion in the mature colony facilitates the movement of resources and organelles throughout an established colony. Approximately 50 proteins have been shown to be important for somatic cell-cell communication and fusion in the model filamentous fungus Neurospora crassa. Genetic, biochemical, and microscopic techniques were used to characterize the functions of seven previously poorly characterized cell fusion proteins. HAM-6, HAM-7 and HAM-8 share functional characteristics and are proposed to function in the same signaling network. Our data suggest that these proteins may form a sensor complex at the cell wall/plasma membrane for the MAK-1 cell wall integrity mitogen-activated protein kinase (MAPK pathway. We also demonstrate that HAM-9, HAM-10, AMPH-1 and WHI-2 have more general functions and are required for normal growth and development. The activation status of the MAK-1 and MAK-2 MAPK pathways are altered in mutants lacking these proteins. We propose that these proteins may function to coordinate the activities of the two MAPK modules with other signaling pathways during cell fusion.

  14. Characterization of the Neurospora crassa cell fusion proteins, HAM-6, HAM-7, HAM-8, HAM-9, HAM-10, AMPH-1 and WHI-2.

    Science.gov (United States)

    Fu, Ci; Ao, Jie; Dettmann, Anne; Seiler, Stephan; Free, Stephen J

    2014-01-01

    Intercellular communication of vegetative cells and their subsequent cell fusion is vital for different aspects of growth, fitness, and differentiation of filamentous fungi. Cell fusion between germinating spores is important for early colony establishment, while hyphal fusion in the mature colony facilitates the movement of resources and organelles throughout an established colony. Approximately 50 proteins have been shown to be important for somatic cell-cell communication and fusion in the model filamentous fungus Neurospora crassa. Genetic, biochemical, and microscopic techniques were used to characterize the functions of seven previously poorly characterized cell fusion proteins. HAM-6, HAM-7 and HAM-8 share functional characteristics and are proposed to function in the same signaling network. Our data suggest that these proteins may form a sensor complex at the cell wall/plasma membrane for the MAK-1 cell wall integrity mitogen-activated protein kinase (MAPK) pathway. We also demonstrate that HAM-9, HAM-10, AMPH-1 and WHI-2 have more general functions and are required for normal growth and development. The activation status of the MAK-1 and MAK-2 MAPK pathways are altered in mutants lacking these proteins. We propose that these proteins may function to coordinate the activities of the two MAPK modules with other signaling pathways during cell fusion.

  15. Characterization of the Neurospora crassa Cell Fusion Proteins, HAM-6, HAM-7, HAM-8, HAM-9, HAM-10, AMPH-1 and WHI-2

    Science.gov (United States)

    Fu, Ci; Ao, Jie; Dettmann, Anne; Seiler, Stephan; Free, Stephen J.

    2014-01-01

    Intercellular communication of vegetative cells and their subsequent cell fusion is vital for different aspects of growth, fitness, and differentiation of filamentous fungi. Cell fusion between germinating spores is important for early colony establishment, while hyphal fusion in the mature colony facilitates the movement of resources and organelles throughout an established colony. Approximately 50 proteins have been shown to be important for somatic cell-cell communication and fusion in the model filamentous fungus Neurospora crassa. Genetic, biochemical, and microscopic techniques were used to characterize the functions of seven previously poorly characterized cell fusion proteins. HAM-6, HAM-7 and HAM-8 share functional characteristics and are proposed to function in the same signaling network. Our data suggest that these proteins may form a sensor complex at the cell wall/plasma membrane for the MAK-1 cell wall integrity mitogen-activated protein kinase (MAPK) pathway. We also demonstrate that HAM-9, HAM-10, AMPH-1 and WHI-2 have more general functions and are required for normal growth and development. The activation status of the MAK-1 and MAK-2 MAPK pathways are altered in mutants lacking these proteins. We propose that these proteins may function to coordinate the activities of the two MAPK modules with other signaling pathways during cell fusion. PMID:25279949

  16. Phase 3 study of recombinant factor VIII Fc fusion protein in severe hemophilia A

    Science.gov (United States)

    Mahlangu, Johnny; Powell, Jerry S.; Ragni, Margaret V.; Chowdary, Pratima; Josephson, Neil C.; Pabinger, Ingrid; Hanabusa, Hideji; Gupta, Naresh; Kulkarni, Roshni; Fogarty, Patrick; Perry, David; Shapiro, Amy; Pasi, K. John; Apte, Shashikant; Nestorov, Ivan; Jiang, Haiyan; Li, Shuanglian; Neelakantan, Srividya; Cristiano, Lynda M.; Goyal, Jaya; Sommer, Jurg M.; Dumont, Jennifer A.; Dodd, Nigel; Nugent, Karen; Vigliani, Gloria; Luk, Alvin; Brennan, Aoife

    2014-01-01

    This phase 3 pivotal study evaluated the safety, efficacy, and pharmacokinetics of a recombinant FVIII Fc fusion protein (rFVIIIFc) for prophylaxis, treatment of acute bleeding, and perioperative hemostatic control in 165 previously treated males aged ≥12 years with severe hemophilia A. The study had 3 treatment arms: arm 1, individualized prophylaxis (25-65 IU/kg every 3-5 days, n = 118); arm 2, weekly prophylaxis (65 IU/kg, n = 24); and arm 3, episodic treatment (10-50 IU/kg, n = 23). A subgroup compared recombinant FVIII (rFVIII) and rFVIIIFc pharmacokinetics. End points included annualized bleeding rate (ABR), inhibitor development, and adverse events. The terminal half-life of rFVIIIFc (19.0 hours) was extended 1.5-fold vs rFVIII (12.4 hours; P < .001). Median ABRs observed in arms 1, 2, and 3 were 1.6, 3.6, and 33.6, respectively. In arm 1, the median weekly dose was 77.9 IU/kg; approximately 30% of subjects achieved a 5-day dosing interval (last 3 months on study). Across arms, 87.3% of bleeding episodes resolved with 1 injection. Adverse events were consistent with those expected in this population; no subjects developed inhibitors. rFVIIIFc was well-tolerated, had a prolonged half-life compared with rFVIII, and resulted in low ABRs when dosed prophylactically 1 to 2 times per week. This trial was registered at www.clinicaltrials.gov as #NCT01181128. PMID:24227821

  17. Effect of rTMP-GH recombinant fusion protein on thrombocytopoiesis in irradiation injured mice

    International Nuclear Information System (INIS)

    Xu Yang; Wang Junping; Chen Fang; Shen Mingqiang; Chen Mo; Wang Song; Ran Xinze; Su Yongping; Kai Li

    2009-01-01

    Objective: To investigate the in vivo effects of rTMP-GH recombinant fusion protein on thrombocytopoiesis in mice with thrombopenia inflicted by irradiation. Methods: BALB/C mice weighting around 20 g were irradiated with 5 Gy of 60 Co γ-ray irradiation to generate thrombopenia. The irradiation injured mice were injected with rTMP-GH or rhGH subcutaneously at the dose of 200 (μg ·kg -1 · d -1 for 7 days. From the 6 th day, the platelets in blood samples from vena caudalis were counted routinely, and the pathological changes of bone marrow were determined by morphological observation. Results: From the 10 th day, the levels of blood platelet in rTMP-GH treated mice were much higher than those of rhGH treatment group and normal saline (NS) control group, especially at the nadir (P < 0.01). On the 22 nd day, the platelet count has recovered up to 80% of normal level in rTMP-GH treatment group, while it has just recovered up to 30% in NS control group. Morphological observation showed that there was obvious reconstruction of bone marrow in mice treated with rTMP-GH, compared with NS group.The number of megarkaryoblasts and megakaryocytes in bone marrow of rTMP-GH treated mice (3.07 ± 0.32) was much higher than those of rhGH treatment group (2.20 ± 0.22, P < 0.05) and NS control group (0.87 ± 0.19, P <0.01). Conclusions: rTMP-GH has potent effects on the recovery of blood platelet by promoting megarkaryocytopoiesis in irradiation injuried mice. (authors)

  18. [Characterization of a recombinant Listeria monocytogenes strain containing the fusion protein gene of Newcastle disease virus].

    Science.gov (United States)

    Xu, Jing-Jing; Jiang, Ling-Li; Chen, Ning; Shuai, Jiang-Bing; Fang, Wei-Huan

    2006-06-01

    Homologous recombination was utilized for construction of a recombinant strain of L. monocytogenes carrying a gene from the Newcastle diseases virus by insertional mutation targeting its listeriolysin O gene (hly). The gene encoding fusion protein of the Newcastle disease virus (NDV-F) was used as the model heterologous gene. The F gene was inserted into hly downstream to its promoter and signal sequence by overlapping extension polymerase chain reaction, which was then subcloned into the shuttle plasmid pKSV7 for allelic exchange with L. monocytogenes chromosome. PCR amplification of the target genes indicated insertion of the F gene into the chromosome DNA of L. monocytogenes. RT-PCR showed transcription of F gene from the recombinant L. monocytogenes strain. Comparisons were then made between the recombinant strain and its wild parent strain in terms of the hemolytic activity, adhesion and invasiveness to cultured HeLa cells, virulence to mice and chicken embryos, and growth kinetics in broth medium as well as its stability upon repeated subculturing and serial passages in mice. The recombinant L. monocytogenes lost its hemolytic activity on the blood agar and had no hemolytic titer from its culture supernatants as compared with the titer of 24 in the supernatant from the wild parent strain. The recombinant strain also had lower adhesiveness (P > 0.05) and significantly lower relative invasiveness to the HeLa cells than its wild type strain (P gene NDV-F from its genomic DNA after subculturing in BHI broth or in mice for 5 times.

  19. Enhanced neutralization potency of botulinum neurotoxin antibodies using a red blood cell-targeting fusion protein.

    Directory of Open Access Journals (Sweden)

    Sharad P Adekar

    2011-03-01

    Full Text Available Botulinum neurotoxin (BoNT potently inhibits cholinergic signaling at the neuromuscular junction. The ideal countermeasures for BoNT exposure are monoclonal antibodies or BoNT antisera, which form BoNT-containing immune complexes that are rapidly cleared from the general circulation. Clearance of opsonized toxins may involve complement receptor-mediated immunoadherence to red blood cells (RBC in primates or to platelets in rodents. Methods of enhancing immunoadherence of BoNT-specific antibodies may increase their potency in vivo. We designed a novel fusion protein (FP to link biotinylated molecules to glycophorin A (GPA on the RBC surface. The FP consists of an scFv specific for murine GPA fused to streptavidin. FP:mAb:BoNT complexes bound specifically to the RBC surface in vitro. In a mouse model of BoNT neutralization, the FP increased the potency of single and double antibody combinations in BoNT neutralization. A combination of two antibodies with the FP gave complete neutralization of 5,000 LD50 BoNT in mice. Neutralization in vivo was dependent on biotinylation of both antibodies and correlated with a reduction of plasma BoNT levels. In a post-exposure model of intoxication, FP:mAb complexes gave complete protection from a lethal BoNT/A1 dose when administered within 2 hours of toxin exposure. In a pre-exposure prophylaxis model, mice were fully protected for 72 hours following administration of the FP:mAb complex. These results demonstrate that RBC-targeted immunoadherence through the FP is a potent enhancer of BoNT neutralization by antibodies in vivo.

  20. Expression of ERG Protein and TMRPSS2-ERG Fusion in Prostatic Carcinoma in Egyptian Patients

    Directory of Open Access Journals (Sweden)

    Ahmed Abdel-Hady

    2017-03-01

    CONCLUSION: Our findings emphasise that only malignant and pre-malignant cells and not benign cells from the prostate stain positive. ERG expression may offer a simpler, accurate and less costly alternative for evaluation of ERG fusion status in PCa.

  1. Structure-Function Studies Link Class II Viral Fusogens with the Ancestral Gamete Fusion Protein HAP2.

    Science.gov (United States)

    Pinello, Jennifer Fricke; Lai, Alex L; Millet, Jean K; Cassidy-Hanley, Donna; Freed, Jack H; Clark, Theodore G

    2017-03-06

    The conserved transmembrane protein, HAP2/GCS1, has been linked to fertility in a wide range of taxa and is hypothesized to be an ancient gamete fusogen. Using template-based structural homology modeling, we now show that the ectodomain of HAP2 orthologs from Tetrahymena thermophila and other species adopt a protein fold remarkably similar to the dengue virus E glycoprotein and related class II viral fusogens. To test the functional significance of this predicted structure, we developed a flow-cytometry-based assay that measures cytosolic exchange across the conjugation junction to rapidly probe the effects of HAP2 mutations in the Tetrahymena system. Using this assay, alterations to a region in and around a predicted "fusion loop" in T. thermophila HAP2 were found to abrogate membrane pore formation in mating cells. Consistent with this, a synthetic peptide corresponding to the HAP2 fusion loop was found to interact directly with model membranes in a variety of biophysical assays. These results raise interesting questions regarding the evolutionary relationships of class II membrane fusogens and harken back to a long-held argument that eukaryotic sex arose as the byproduct of selection for the horizontal transfer of a "selfish" genetic element from cell to cell via membrane fusion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Ebolavirus Glycoprotein Fc Fusion Protein Protects Guinea Pigs against Lethal Challenge

    Science.gov (United States)

    Konduru, Krishnamurthy; Shurtleff, Amy C.; Bradfute, Steven B.; Nakamura, Siham; Bavari, Sina; Kaplan, Gerardo

    2016-01-01

    Ebola virus (EBOV), a member of the Filoviridae that can cause severe hemorrhagic fever in humans and nonhuman primates, poses a significant threat to the public health. Currently, there are no licensed vaccines or therapeutics to prevent and treat EBOV infection. Several vaccines based on the EBOV glycoprotein (GP) are under development, including vectored, virus-like particles, and protein-based subunit vaccines. We previously demonstrated that a subunit vaccine containing the extracellular domain of the Ebola ebolavirus (EBOV) GP fused to the Fc fragment of human IgG1 (EBOVgp-Fc) protected mice against EBOV lethal challenge. Here, we show that the EBOVgp-Fc vaccine formulated with QS-21, alum, or polyinosinic-polycytidylic acid-poly-L-lysine carboxymethylcellulose (poly-ICLC) adjuvants induced strong humoral immune responses in guinea pigs. The vaccinated animals developed anti-GP total antibody titers of approximately 105−106 and neutralizing antibody titers of approximately 103 as assessed by a BSL-2 neutralization assay based on vesicular stomatitis virus (VSV) pseudotypes. The poly-ICLC formulated EBOVgp-Fc vaccine protected all the guinea pigs against EBOV lethal challenge performed under BSL-4 conditions whereas the same vaccine formulated with QS-21 or alum only induced partial protection. Vaccination with a mucin-deleted EBOVgp-Fc construct formulated with QS-21 adjuvant did not have a significant effect in anti-GP antibody levels and protection against EBOV lethal challenge compared to the full-length GP construct. The bulk of the humoral response induced by the EBOVgp-Fc vaccine was directed against epitopes outside the EBOV mucin region. Our findings indicate that different adjuvants can eliciting varying levels of protection against lethal EBOV challenge in guinea pigs vaccinated with EBOVgp-Fc, and suggest that levels of total anti-GP antibodies elicit by protein-based GP subunit vaccines do not correlate with protection. Our data further support

  3. High yield purification of nanobodies from the periplasm of E. coli as fusions with the maltose binding protein.

    Science.gov (United States)

    Salema, Valencio; Fernández, Luis Ángel

    2013-09-01

    Nanobodies (Nbs) are single domain antibodies based on the variable domains of heavy chain only antibodies (HCAbs) found in camelids, also referred to as VHHs. Their small size (ca. 12-15kDa), superior biophysical and antigen binding properties have made Nbs very attractive molecules for multiple biotechnological applications, including human therapy. The most widely used system for the purification of Nbs is their expression in the periplasm of Escherichia coli with a C-terminal hexa-histidine (His6) tag followed by immobilized metal affinity chromatography (IMAC). However, significant variability in the expression levels of different Nbs are routinely observed and a single affinity chromatography step is often not sufficient to obtain Nbs of high purity. Here, we report an alternative method for expression and purification of Nbs from the periplasm of E. coli based on their fusion to maltose binding protein (MBP) in the N-terminus and His6 tag in the C-terminus (MBP-NbHis6). Soluble MBP-NbHis6 fusions were consistently expressed at high levels (⩾12mg/L of induced culture in shake flasks) in the periplasm of E. coli HM140, a strain deficient in several periplasmic proteases. Highly pure MBP-NbHis6 fusions and free NbHis6 (after site specific proteolysis of the fusions), were recovered by amylose and metal affinity chromatography steps. The monomeric nature of the purified NbHis6 was determined by gel filtration chromatography. Lastly, we demonstrated by ELISA that both monomeric NbHis6 and MBP-NbHis6 fusions retained antigen binding activity and specificity, thus facilitating their direct use in antigen recognition assays. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Unusual Self-Assembly of the Recombinant Chlamydia trachomatis Major Outer Membrane Protein-Based Fusion Antigen CTH522 Into Protein Nanoparticles

    DEFF Research Database (Denmark)

    Rose, Fabrice; Karlsen, Kasper; Jensen, Pernille

    2018-01-01

    but is a challenging vaccine candidate by being an integral membrane protein, and the immunogenicity depends on a correctly folded structure. We investigated the biophysical properties of the recombinant MOMP-based fusion antigen CTH522, which is tested in early human clinical trials. It consists of a truncated......Sexually transmitted Chlamydia trachomatis (Ct) infects more than 100 million people annually, and untreated chlamydia infections can cause severe complications. Therefore, there is an urgent need for a chlamydia vaccine. The Ct major outer membrane protein (MOMP) is highly immunogenic...

  5. Evolution of double MutT/Nudix domain-containing proteins: similar domain architectures from independent gene duplication-fusion events.

    Science.gov (United States)

    Lin, Jun; Hu, Yihuai; Tian, Bing; Hua, Yuejin

    2009-10-01

    The MutT/Nudix superfamily proteins repair DNA damage and play a role in human health and disease. In this study, we examined two different cases of double MutT/Nudix domain-containing proteins from eukaryotes and prokaryotes. Firstly, these double domain proteins were discovered in Drosophila, but only single Nudix domain proteins were found in other animals. The phylogenetic tree was constructed based on the protein sequence of Nudix_N and Nudix_C from Drosophila, and Nudix from other animals. The phylogenetic analysis suggested that the double Nudix domain proteins might have undergone a gene duplication-speciation-fusion process. Secondly, two genes of the MutT family, DR0004 and DR0329, were fused by two mutT gene segments and formed double MutT domain protein genes in Deinococcus radiodurans. The evolutionary tree of bacterial MutT proteins suggested that the double MutT domain proteins in D. radiodurans probably resulted from a gene duplication-fusion event after speciation. Gene duplication-fusion is a basic and important gene innovation mechanism for the evolution of double MutT/Nudix domain proteins. Independent gene duplication-fusion events resulted in similar domain architectures of different double MutT/Nudix domain proteins.

  6. Intracellular expression of IRF9 Stat fusion protein overcomes the defective Jak-Stat signaling and inhibits HCV RNA replication

    Directory of Open Access Journals (Sweden)

    Balart Luis A

    2010-10-01

    Full Text Available Abstract Interferon alpha (IFN-α binds to a cell surface receptor that activates the Jak-Stat signaling pathway. A critical component of this pathway is the translocation of interferon stimulated gene factor 3 (a complex of three proteins Stat1, Stat2 and IRF9 to the nucleus to activate antiviral genes. A stable sub-genomic replicon cell line resistant to IFN-α was developed in which the nuclear translocation of Stat1 and Stat2 proteins was prevented due to the lack of phosphorylation; whereas the nuclear translocation of IRF9 protein was not affected. In this study, we sought to overcome defective Jak-Stat signaling and to induce an antiviral state in the IFN-α resistant replicon cell line by developing a chimera IRF9 protein fused with the trans activating domain (TAD of either a Stat1 (IRF9-S1C or Stat2 (IRF9-S2C protein. We show here that intracellular expression of fusion proteins using the plasmid constructs of either IRF9-S1C or IRF9-S2C, in the IFN-α resistant cells, resulted in an increase in Interferon Stimulated Response Element (ISRE luciferase promoter activity and significantly induced HLA-1 surface expression. Moreover, we show that transient transfection of IRF9-S1C or IRF9-S2C plasmid constructs into IFN-α resistant replicon cells containing sub-genomic HCV1b and HCV2a viruses resulted in an inhibition of viral replication and viral protein expression independent of IFN-α treatment. The results of this study indicate that the recombinant fusion proteins of IRF9-S1C, IRF9-S2C alone, or in combination, have potent antiviral properties against the HCV in an IFN-α resistant cell line with a defective Jak-Stat signaling.

  7. Human Cytomegalovirus gH/gL Forms a Stable Complex with the Fusion Protein gB in Virions.

    Directory of Open Access Journals (Sweden)

    Adam L Vanarsdall

    2016-04-01

    Full Text Available Human cytomegalovirus (HCMV is a ubiquitous virus that is a major pathogen in newborns and immunocompromised or immunosuppressed patients. HCMV infects a wide variety of cell types using distinct entry pathways that involve different forms of the gH/gL glycoprotein: gH/gL/gO and gH/gL/UL128-131 as well as the viral fusion glycoprotein, gB. However, the minimal or core fusion machinery (sufficient for cell-cell fusion is just gH/gL and gB. Here, we demonstrate that HCMV gB and gH/gL form a stable complex early after their synthesis and in the absence of other viral proteins. gH/gL can interact with gB mutants that are unable to mediate cell-cell fusion. gB-gH/gL complexes included as much as 16-50% of the total gH/gL in HCMV virus particles. In contrast, only small amounts of gH/gL/gO and gH/gL/UL128-131 complexes were found associated with gB. All herpesviruses express gB and gH/gL molecules and most models describing herpesvirus entry suggest that gH/gL interacts with gB to mediate membrane fusion, although there is no direct evidence for this. For herpes simplex virus (HSV-1 it has been suggested that after receptor binding gH/gL binds to gB either just before, or coincident with membrane fusion. Therefore, our results have major implications for these models, demonstrating that HCMV gB and gH/gL forms stable gB-gH/gL complexes that are incorporated virions without receptor binding or membrane fusion. Moreover, our data is the best support to date for the proposal that gH/gL interacts with gB.

  8. The N-domain of Escherichia coli phosphoglycerate kinase is a novel fusion partner to express aggregation-prone heterologous proteins.

    Science.gov (United States)

    Song, Jong-Am; Lee, Dae-Sung; Park, Jin-Seung; Han, Kyung-Yeon; Lee, Jeewon

    2012-02-01

    As a fusion partner to express aggregation-prone heterologous proteins, we investigated the efficacy of Escherichia coli phosphoglycerate kinase (ePGK) that consists of two functional domains (N- and C-domain) and reportedly has a high structural stability. When the full-length ePGK (F-ePGK) was used as a fusion partner, the solubility of the heterologous proteins increased, but some of them still had a large fraction of insoluble aggregates. Surprisingly, the fusion expression using the N-domain of ePGK (N-ePGK) made the insoluble fraction significantly reduce to less than 10% for all the heterologous fusion proteins tested. Also, we evaluated the efficacy of N-ePGK in making the target proteins be expressed with their own native function or structure. It was found that of human ferritin light chain, bacterial arginine deiminase, human granulocyte colony stimulating factor were synthesized evidently with the self-assembly function, L-arginine-degrading activity, and the correct secondary structure, respectively, through the fusion expression using N-ePGK. These results indicate that N-ePGK is a highly potent fusion partner that can be widely used for the synthesis of a variety of heterologous proteins in E. coli. Copyright © 2011 Wiley Periodicals, Inc.

  9. A novel set of Wnt-Frizzled fusion proteins identifies receptor components that activate beta -catenin-dependent signaling.

    Science.gov (United States)

    Holmen, Sheri L; Salic, Adrian; Zylstra, Cassandra R; Kirschner, Marc W; Williams, Bart O

    2002-09-20

    Wnt proteins initiate the canonical (beta-catenin-regulated) signaling cascade by binding to seven-transmembrane spanning receptors of the Frizzled (Fz) family together with the coreceptors LRP5 and -6, members of the low density lipoprotein receptor-related protein family (LRP). Several reports have shown physical and functional associations between various Wnt, LRP, and Frizzled molecules; however, the underlying mechanisms for selectivity remain poorly understood. We present data on a novel set of Wnt-Fz fusion constructs that are useful for elucidating mechanisms of Wnt signal transduction specificity in both Xenopus embryos and 293T cells. In 293T cells, coexpression of several Wnt-Fz fusion proteins with LRP6, but not LRP5, significantly activated a Wnt-responsive promoter, Optimized TOPFlash. Interestingly, Wnt proteins from both the Wnt1 and Wnt5A classes, when fused to the same Frizzled, can synergize with LRP6 to activate signaling and induce secondary axes in Xenopus embryos. However, when several Wnt-Fz constructs containing different Frizzled molecules were tested, it was found that all Frizzled molecules are not equivalent in their ability to activate the canonical Wnt pathway in this context. The data suggest that the distinction between the two Wnt classes lies not in intrinsic differences in the molecules but via the Frizzled molecules with which they interact.

  10. New vectors for chromosomal integration enable high-level constitutive or inducible magnetosome expression of fusion proteins in Magnetospirillum gryphiswaldense.

    Science.gov (United States)

    Borg, Sarah; Hofmann, Julia; Pollithy, Anna; Lang, Claus; Schüler, Dirk

    2014-04-01

    The alphaproteobacterium Magnetospirillum gryphiswaldense biomineralizes magnetosomes, which consist of monocrystalline magnetite cores enveloped by a phospholipid bilayer containing specific proteins. Magnetosomes represent magnetic nanoparticles with unprecedented magnetic and physicochemical characteristics. These make them potentially useful in a number of biotechnological and biomedical applications. Further functionalization can be achieved by expression of foreign proteins via genetic fusion to magnetosome anchor peptides. However, the available genetic tool set for strong and controlled protein expression in magnetotactic bacteria is very limited. Here, we describe versatile vectors for either inducible or high-level constitutive expression of proteins in M. gryphiswaldense. The combination of an engineered native PmamDC promoter with a codon-optimized egfp gene (Mag-egfp) resulted in an 8-fold increase in constitutive expression and in brighter fluorescence. We further demonstrate that the widely used Ptet promoter is functional and tunable in M. gryphiswaldense. Stable and uniform expression of the EGFP and β-glucuronidase (GusA) reporters was achieved by single-copy chromosomal insertion via Tn5-mediated transposition. In addition, gene duplication by Mag-EGFP-EGFP fusions to MamC resulted in further increased magnetosome expression and fluorescence. Between 80 and 210 (for single MamC-Mag-EGFP) and 200 and 520 (for MamC-Mag-EGFP-EGFP) GFP copies were estimated to be expressed per individual magnetosome particle.

  11. [Comparison of two types of cell cultures for preparation of sTNFRII-gAD fusion protein].

    Science.gov (United States)

    Huang, Shigao; Yin, Yuting; Xiong, Chunhui; Wang, Caihong; Lü, Jianxin; Gao, Jimin

    2013-01-01

    In this study we used two types of cell cultures, i.e., anchorage-dependent basket and full suspension batch cultures of sTNFRII-gAD-expressing CHO cells in the CelliGen 310 bioreactor (7.5 L) to compare their yields in order to optimize the culturing conditions for efficient expression of sTNFRII-gAD fusion protein consisting of soluble tumor necrosis factor receptor II and globular domain of adiponectin. The anchorage-dependent basket culture was performed in 4L 10% serum-containing medium with the final inoculating concentration of 3 x 10(5) to 4 x 10(5) cells/mL of sTNFRII-gAD-expressing CHO cells for 3 days, and then switched to 4 L serum-free LK021 medium to continue the culture for 4 days. The full suspension batch culture was carried out in the 4 L serum-free LK021 medium with the final inoculating concentration of 3 x 10(5) to 4 x 10(5) cells/mL of sTNFRII-gAD-expressing CHO cells for 7 days. The culturing conditions were monitored in real-time to maintain pH and dissolved oxygen stability through the whole process. The supernatants were collected by centrifuge, and the protein was concentrated through Pellicon flow ultrafiltration system and then purified by DEAE anion exchange. The results showed that the yields of sTNFRII-gAD fusion protein were 8.0 mg/L with 95% purity and 7.5 mg/L with 98% purity in the anchorage-dependent basket and the full suspension batch cultures, respectively. The study provided the framework for the pilot production of sTNFRII-gAD fusion protein.

  12. Human Serum Albumin and HER2-Binding Affibody Fusion Proteins for Targeted Delivery of Fatty Acid-Modified Molecules and Therapy.

    Science.gov (United States)

    Dong, Daoyuan; Xia, Guanjun; Li, Zhijun; Li, Zhiyu

    2016-10-03

    Human epidermal growth factor receptor 2 (HER2) is a well-studied therapeutic target as well as a biomarker of breast cancer. HER2-targeting affibody (Z HER2:342 ) is a novel small scaffold protein with an extreme high affinity against HER2 screened by phage display. However, the small molecular weight of Z HER2:342 has limited its pharmaceutical application. Human serum albumin (HSA) and Z HER2:342 fusion protein may not only extend the serum half-life of Z HER2:342 but also preserve the biological function of HSA to bind and transport fatty acids, which can be used to deliver fatty acid-modified therapeutics to HER2-positive cancer cells. Two HSA and Z HER2:342 fusion proteins, one with a single Z HER2:342 domain fused to the C terminus of HSA (rHSA-ZHER2) and another with two tandem copies of Z HER2:342 fused to the C terminus of HSA (rHSA-(ZHER2) 2 ), have been constructed, expressed, and purified. Both fusion proteins possessed the HER2 and fatty acid (FA) binding abilities demonstrated by in vitro assays. Interestingly, rHSA-(ZHER2) 2 , not rHSA-ZHER2, was able to inhibit the proliferation of SK-BR-3 cells at a relatively low concentration, and the increase of HER2 and ERK1/2 phosphorylation followed by rHSA-(ZHER2) 2 treatment has been observed. HSA fusion proteins are easy and economical to express, purify, and formulate. As expected, HSA fusion proteins and fusion protein-bound fatty acid-modified FITC could be efficiently taken up by cells. These results proved the feasibility of using HSA fusion proteins as therapeutic agents as well as carriers for targeted drug delivery.

  13. IL-2/neuroantigen fusion proteins as antigen-specific tolerogens in experimental autoimmune encephalomyelitis (EAE): correlation of T cell-mediated antigen presentation and tolerance induction.

    Science.gov (United States)

    Mannie, Mark D; Clayson, Barbara A; Buskirk, Elizabeth J; DeVine, Jarret L; Hernandez, Jose J; Abbott, Derek J

    2007-03-01

    The purpose of this study was to assess whether the Ag-targeting activity of cytokine/neuroantigen (NAg) fusion proteins may be associated with mechanisms of tolerance induction. To assess this question, we expressed fusion proteins comprised of a N-terminal cytokine domain and a C-terminal NAg domain. The cytokine domain comprised either rat IL-2 or IL-4, and the NAg domain comprised the dominant encephalitogenic determinant of the guinea pig myelin basic protein. Subcutaneous administration of IL2NAg (IL-2/NAg fusion protein) into Lewis rats either before or after an encephalitogenic challenge resulted in an attenuated course of experimental autoimmune encephalomyelitis. In contrast, parallel treatment of rats with IL4NAg (IL-4/NAg fusion protein) or NAg lacked tolerogenic activity. In the presence of IL-2R(+) MHC class II(+) T cells, IL2NAg fusion proteins were at least 1,000 times more potent as an Ag than NAg alone. The tolerogenic activity of IL2NAg in vivo and the enhanced potency in vitro were both dependent upon covalent linkage of IL-2 and NAg. IL4NAg also exhibited enhanced antigenic potency. IL4NAg was approximately 100-fold more active than NAg alone in the presence of splenic APC. The enhanced potency of IL4NAg also required covalent linkage of cytokine and NAg and was blocked by soluble IL-4 or by a mAb specific for IL-4. Other control cytokine/NAg fusion proteins did not exhibit a similar enhancement of Ag potency compared with NAg alone. Thus, the IL2NAg and IL4NAg fusion proteins targeted NAg for enhanced presentation by particular subsets of APC. The activities of IL2NAg revealed a potential relationship between NAg targeting to activated T cells, T cell-mediated Ag presentation, and tolerance induction.

  14. Self-Immobilization of Car9 Fusion Proteins within High Surface Area Silica Sol-Gels and Dynamic Control of Protein Release.

    Science.gov (United States)

    Yang, Wenlan; Hellner, Brittney; Baneyx, François

    2016-10-19

    Protein entrapment within silica matrices during sol-gel formation is an effective way of producing biocatalysts with high load, activity retention, and minimal leaching. On the other hand, mesoporous silica materials have been favored for diffusional control of protein delivery because of their regular pore size and morphology and in spite of the drawback of requiring post-synthesis loading with cargo proteins. Here, we describe a hybrid technology in which fusion of the silica-binding Car9 dodecapeptide to model fluorescent proteins allows for their simultaneous entrapment and surface immobilization within sol-gel monoliths that can be fabricated in air and oil phases. Spherical particles produced by injecting a mixture of silicic acid and Car9-tagged proteins in silicone oil exhibit high surface area (>400 m 2 /g), 15-nm-diameter mean pore size and homogeneous protein loading. Incubation in arginine-containing buffer disrupts the interaction between Car9 extensions and silica surfaces and triggers the continuous or discontinuous (on/off) release of cargo proteins with pH-tunable kinetics. This simple approach for producing hybrid silica materials that stably encapsulate and release one or more Car9-tagged proteins in a single step may prove useful for applications requiring dynamic control of protein concentration.

  15. Meningeal hemangiopericytoma and solitary fibrous tumors carry the NAB2-STAT6 fusion and can be diagnosed by nuclear expression of STAT6 protein.

    Science.gov (United States)

    Schweizer, Leonille; Koelsche, Christian; Sahm, Felix; Piro, Rosario M; Capper, David; Reuss, David E; Pusch, Stefan; Habel, Antje; Meyer, Jochen; Göck, Tanja; Jones, David T W; Mawrin, Christian; Schittenhelm, Jens; Becker, Albert; Heim, Stephanie; Simon, Matthias; Herold-Mende, Christel; Mechtersheimer, Gunhild; Paulus, Werner; König, Rainer; Wiestler, Otmar D; Pfister, Stefan M; von Deimling, Andreas

    2013-05-01

    Non-central nervous system hemangiopericytoma (HPC) and solitary fibrous tumor (SFT) are considered by pathologists as two variants of a single tumor entity now subsumed under the entity SFT. Recent detection of frequent NAB2-STAT6 fusions in both, HPC and SFT, provided additional support for this view. On the other hand, current neuropathological practice still distinguishes between HPC and SFT. The present study set out to identify genes involved in the formation of meningeal HPC. We performed exome sequencing and detected the NAB2-STAT6 fusion in DNA of 8/10 meningeal HPC thereby providing evidence of close relationship of these tumors with peripheral SFT. Due to the considerable effort required for exome sequencing, we sought to explore surrogate markers for the NAB2-STAT6 fusion protein. We adopted the Duolink proximity ligation assay and demonstrated the presence of NAB2-STAT6 fusion protein in 17/17 HPC and the absence in 15/15 meningiomas. More practical, presence of the NAB2-STAT6 fusion protein resulted in a strong nuclear signal in STAT6 immunohistochemistry. The nuclear reallocation of STAT6 was detected in 35/37 meningeal HPC and 25/25 meningeal SFT but not in 87 meningiomas representing the most important differential diagnosis. Tissues not harboring the NAB2-STAT6 fusion protein presented with nuclear expression of NAB2 and cytoplasmic expression of STAT6 proteins. In conclusion, we provide strong evidence for meningeal HPC and SFT to constitute variants of a single entity which is defined by NAB2-STAT6 fusion. In addition, we demonstrate that this fusion can be rapidly detected by STAT6 immunohistochemistry which shows a consistent nuclear reallocation. This immunohistochemical assay may prove valuable for the differentiation of HPC and SFT from other mesenchymal neoplasms.

  16. Effect of insecticidal fusion proteins containing spider toxins targeting sodium and calcium ion channels on pyrethroid-resistant strains of peach-potato aphid (Myzus persicae).

    Science.gov (United States)

    Yang, Sheng; Fitches, Elaine; Pyati, Prashant; Gatehouse, John A

    2015-07-01

    The recombinant fusion proteins Pl1a/GNA and Hv1a/GNA contain the spider venom peptides δ-amaurobitoxin-PI1a or ω-hexatoxin-Hv1a respectively, linked to snowdrop lectin (GNA). Pl1a targets receptor site 4 of insect voltage-gated sodium channels (NaCh), while Hv1a targets voltage-gated calcium channels. Insecticide-resistant strains of peach-potato aphid (Myzus persicae) contain mutations in NaCh. The pyrethroid-resistant kdr (794J) and super-kdr (UKO) strains contain mutations at residues L1014 and M918 in the channel α-subunit respectively, while the kdr + super-kdr strain (4824J), insensitive to pyrethroids, contains mutations at both L1014 and M918. Pl1a/GNA and Hv1a/GNA fusion proteins have estimated LC50 values of 0.35 and 0.19 mg mL(-1) when fed to wild-type M. persicae. For insecticide-resistant aphids, LC50 for the Pl1a/GNA fusion protein increased by 2-6-fold, correlating with pyrethroid resistance (wild type < kdr < super-kdr < kdr + super-kdr strains). In contrast, LC50 for the Hv1a/GNA fusion protein showed limited correlation with pyrethroid resistance. Mutations in the sodium channel in pyrethroid-resistant aphids also protect against a fusion protein containing a sodium-channel-specific toxin, in spite of differences in ligand-channel interactions, but do not confer resistance to a fusion protein targeting calcium channels. The use of fusion proteins with differing targets could play a role in managing pesticide resistance. © 2014 Society of Chemical Industry.

  17. Junction region of EWS-FLI1 fusion protein has a dominant negative effect in Ewing’s Sarcoma in vitro

    International Nuclear Information System (INIS)

    Jully, Babu; Vijayalakshmi, Ramshankar; Gopal, Gopisetty; Sabitha, Kesavan; Rajkumar, Thangarajan

    2012-01-01

    Ewing’s sarcoma is a malignancy characterized by a specific 11:22 chromosomal translocation which generates a novel EWS-FLI1 fusion protein functioning as an aberrant transcription factor. In the present study, we have further characterized the junction region of the EWS-FLI1 fusion protein. In-silico model of EWS-FLI1 fusion protein was analysed for ligand binding sites, and a putative region (amino acid (aa) 251–343 of the type 1 fusion protein) in the vicinity of the fusion junction was cloned and expressed using bacterial expression. The recombinant protein was characterized by Circular Dichroism (CD). We then expressed aa 251–280 ectopically in Ewing’s sarcoma cell-line and its effect on cell proliferation, tumorigenicity and expression of EWS-FLI1 target genes were analysed. Our modelling analysis indicated that Junction region (aa 251–343) encompasses potential ligand biding sites in the EWS-FLI1 protein and when expressed in bacteria was present as soluble form. Ectopically expressing this region in Ewing’s sarcoma cells inhibited tumorigenicity, and EWS-FLI1 target genes indicating a dominant negative biological effect. Junction region can be exploited further as target for drug development in future to specifically target EWS-FLI1 in Ewing’s Sarcoma

  18. Screening Fusion Tags for Improved Recombinant Protein Expression in E. coli with the Expresso® Solubility and Expression Screening System.

    Science.gov (United States)

    Steinmetz, Eric J; Auldridge, Michele E

    2017-11-01

    The simplicity, speed, and low cost of bacterial culture make E. coli the system of choice for most initial trials of recombinant protein expression. However, many heterologous proteins are either poorly expressed in bacteria, or are produced as incorrectly folded, insoluble aggregates that lack the activity of the native protein. I