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Moser C, Muhle-Goll C. Cell-free protein production of a gamma secretase homolog. Protein Expr Purif 2024; 215:106407. [PMID: 38000778 DOI: 10.1016/j.pep.2023.106407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/17/2023] [Accepted: 11/19/2023] [Indexed: 11/26/2023]
Abstract
Cleavage of the transmembrane domain (TMD) of amyloid-β precursor protein (APP) by γ-secretase, an intramembrane aspartyl protease, generates Aβ peptides of various lengths that form plaques in the brains of Alzheimer's disease patients. Although the debate has not been finally resolved whether these plaques trigger the onset of Alzheimer's or are side products, disease-related mutations suggest their implication in the etiology of the dementia. These occur both in presenilin, the catalytic subunit of γ-secretase, and in the TMD of APP. Despite two seminal cryo-electron microscopy structures that show the complex of γ-secretase with its substrates APP and Notch, the mechanism of γ-secretase is not yet fully understood. Especially on which basis it selects its substrates is still an enigma. The presenilin homolog PSH from the archaeon Methanoculleus marisnigri JR1 (MCMJR1) is catalytically active without accessory proteins in contrast to γ-secretase making it an excellent model for studies of the basic cleavage process. We here focused on the cell-free expression of PSH screening a range of conditions. Cleavage assays to verify the activity show that not only the yield, but mainly the activity of the protease depends on the careful selection of expression conditions. Optimal results were found for a cell-free expression at relatively low temperature, 20 °C, employing cell lysates prepared from E. coli Rosetta cells. To speed up protein preparation for immediate functional assays, a crude purification protocol was developed. This allows to produce ready-made PSH in a fast and efficient manner in less than two days.
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Affiliation(s)
- Celine Moser
- Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, 76344 Eggenstein- Leopoldshafen, Germany; Institute of Organic Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Claudia Muhle-Goll
- Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, 76344 Eggenstein- Leopoldshafen, Germany; Institute of Organic Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
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2
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Cell-free synthesis of amyloid fibrils with infectious properties and amenable to sub-milligram magic-angle spinning NMR analysis. Commun Biol 2022; 5:1202. [DOI: 10.1038/s42003-022-04175-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
Abstract
AbstractStructural investigations of amyloid fibrils often rely on heterologous bacterial overexpression of the protein of interest. Due to their inherent hydrophobicity and tendency to aggregate as inclusion bodies, many amyloid proteins are challenging to express in bacterial systems. Cell-free protein expression is a promising alternative to classical bacterial expression to produce hydrophobic proteins and introduce NMR-active isotopes that can improve and speed up the NMR analysis. Here we implement the cell-free synthesis of the functional amyloid prion HET-s(218-289). We present an interesting case where HET-s(218-289) directly assembles into infectious fibril in the cell-free expression mixture without the requirement of denaturation procedures and purification. By introducing tailored 13C and 15N isotopes or CF3 and 13CH2F labels at strategic amino-acid positions, we demonstrate that cell-free synthesized amyloid fibrils are readily amenable to high-resolution magic-angle spinning NMR at sub-milligram quantity.
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3
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Pacull EM, Sendker F, Bernhard F, Scheidt HA, Schmidt P, Huster D, Krug U. Integration of Cell-Free Expression and Solid-State NMR to Investigate the Dynamic Properties of Different Sites of the Growth Hormone Secretagogue Receptor. Front Pharmacol 2020; 11:562113. [PMID: 33324203 PMCID: PMC7723455 DOI: 10.3389/fphar.2020.562113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/21/2020] [Indexed: 01/09/2023] Open
Abstract
Cell-free expression represents an attractive method to produce large quantities of selectively labeled protein for NMR applications. Here, cell-free expression was used to label specific regions of the growth hormone secretagogue receptor (GHSR) with NMR-active isotopes. The GHSR is a member of the class A family of G protein-coupled receptors. A cell-free expression system was established to produce the GHSR in the precipitated form. The solubilized receptor was refolded in vitro and reconstituted into DMPC lipid membranes. Methionines, arginines, and histidines were chosen for 13C-labeling as they are representative for the transmembrane domains, the loops and flanking regions of the transmembrane α-helices, and the C-terminus of the receptor, respectively. The dynamics of the isotopically labeled residues was characterized by solid-state NMR measuring motionally averaged 1H-13C dipolar couplings, which were converted into molecular order parameters. Separated local field DIPSHIFT experiments under magic-angle spinning conditions using either varying cross polarization contact times or direct excitation provided order parameters for these residues showing that the C-terminus was the segment with the highest motional amplitude. The loop regions and helix ends as well as the transmembrane regions of the GHSR represent relatively rigid segments in the overall very flexible receptor molecule. Although no site resolution could be achieved in the experiments, the previously reported highly dynamic character of the receptor concluded from uniformly 13C labeled receptor samples could be further specified by this segmental labeling approach, leading to a more diversified understanding of the receptor dynamics under equilibrium conditions.
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Affiliation(s)
- Emelyne M Pacull
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
| | - Franziska Sendker
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt am Main, Germany.,Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Holger A Scheidt
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
| | - Peter Schmidt
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
| | - Ulrike Krug
- Institute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
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4
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Cell-Free Protein Synthesis of Small Intrinsically Disordered Proteins for NMR Spectroscopy. Methods Mol Biol 2020. [PMID: 32696360 DOI: 10.1007/978-1-0716-0524-0_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Cell-free protein synthesis (CFPS) is an established method to produce recombinant proteins and has been used in a wide variety of applications. The use of CFPS has almost from the onset been favorably linked to the production of isotopically labelled proteins for NMR spectroscopy as the resulting labelling of the produced protein is defined by the chosen amino acids during reaction setup. Here we describe how to set up production and isotopic labelling of small intrinsically disordered proteins (IDPs) for NMR spectroscopy applications using an E. coli-based CFPS system in batch mode.
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Petrella S, Capton E, Raynal B, Giffard C, Thureau A, Bonneté F, Alzari PM, Aubry A, Mayer C. Overall Structures of Mycobacterium tuberculosis DNA Gyrase Reveal the Role of a Corynebacteriales GyrB-Specific Insert in ATPase Activity. Structure 2019; 27:579-589.e5. [PMID: 30744994 DOI: 10.1016/j.str.2019.01.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/13/2018] [Accepted: 01/14/2019] [Indexed: 01/03/2023]
Abstract
Despite sharing common features, previous studies have shown that gyrases from different species have been modified throughout evolution to modulate their properties. Here, we report two crystal structures of Mycobacterium tuberculosis DNA gyrase, an apo and AMPPNP-bound form at 2.6-Å and 3.3-Å resolution, respectively. These structures provide high-resolution structural data on the quaternary organization and interdomain connections of a gyrase (full-length GyrB-GyrA57)2 thus providing crucial inputs on this essential drug target. Together with small-angle X-ray scattering studies, they revealed an "extremely open" N-gate state, which persists even in the DNA-free gyrase-AMPPNP complex and an unexpected connection between the ATPase and cleavage core domains mediated by two Corynebacteriales-specific motifs, respectively the C-loop and DEEE-loop. We show that the C-loop participates in the stabilization of this open conformation, explaining why this gyrase has a lower ATPase activity. Our results image a conformational state which might be targeted for drug discovery.
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Affiliation(s)
- Stéphanie Petrella
- Unité de Microbiologie Structurale, Institut Pasteur, CNRS UMR 3528, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France.
| | - Estelle Capton
- Sorbonne Université, Centre d'Immunologie et des Maladies Infectieuses-Paris, Cimi-Paris, INSERM U1135, National Reference Center for Mycobacteria, Laboratoire de Bactériologie-Hygiène, AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière - Charles Foix, 75013 Paris, France
| | - Bertrand Raynal
- Plateforme de Biophysique Moléculaire, Institut Pasteur, CNRS UMR 3528, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Clément Giffard
- Unité de Microbiologie Structurale, Institut Pasteur, CNRS UMR 3528, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Aurélien Thureau
- Synchrotron SOLEIL, l'Orme des Merisiers, 91410 Saint Aubin, France
| | - Françoise Bonneté
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Institut de Biologie Physico-Chimique, CNRS UMR7099 and Université Paris Didérot, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Pedro M Alzari
- Unité de Microbiologie Structurale, Institut Pasteur, CNRS UMR 3528, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Alexandra Aubry
- Sorbonne Université, Centre d'Immunologie et des Maladies Infectieuses-Paris, Cimi-Paris, INSERM U1135, National Reference Center for Mycobacteria, Laboratoire de Bactériologie-Hygiène, AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière - Charles Foix, 75013 Paris, France.
| | - Claudine Mayer
- Unité de Microbiologie Structurale, Institut Pasteur, CNRS UMR 3528, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
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Dilworth MV, Piel MS, Bettaney KE, Ma P, Luo J, Sharples D, Poyner DR, Gross SR, Moncoq K, Henderson PJF, Miroux B, Bill RM. Microbial expression systems for membrane proteins. Methods 2018; 147:3-39. [PMID: 29656078 DOI: 10.1016/j.ymeth.2018.04.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/08/2018] [Accepted: 04/10/2018] [Indexed: 12/19/2022] Open
Abstract
Despite many high-profile successes, recombinant membrane protein production remains a technical challenge; it is still the case that many fewer membrane protein structures have been published than those of soluble proteins. However, progress is being made because empirical methods have been developed to produce the required quantity and quality of these challenging targets. This review focuses on the microbial expression systems that are a key source of recombinant prokaryotic and eukaryotic membrane proteins for structural studies. We provide an overview of the host strains, tags and promoters that, in our experience, are most likely to yield protein suitable for structural and functional characterization. We also catalogue the detergents used for solubilization and crystallization studies of these proteins. Here, we emphasize a combination of practical methods, not necessarily high-throughput, which can be implemented in any laboratory equipped for recombinant DNA technology and microbial cell culture.
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Affiliation(s)
- Marvin V Dilworth
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Mathilde S Piel
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR 7099, CNRS, Université Paris Diderot, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Kim E Bettaney
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Pikyee Ma
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Ji Luo
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - David Sharples
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - David R Poyner
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Stephane R Gross
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Karine Moncoq
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR 7099, CNRS, Université Paris Diderot, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Peter J F Henderson
- Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK.
| | - Bruno Miroux
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR 7099, CNRS, Université Paris Diderot, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Roslyn M Bill
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
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Mechaly AE, Soto Diaz S, Sassoon N, Buschiazzo A, Betton JM, Alzari PM. Structural Coupling between Autokinase and Phosphotransferase Reactions in a Bacterial Histidine Kinase. Structure 2017; 25:939-944.e3. [PMID: 28552574 DOI: 10.1016/j.str.2017.04.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 03/06/2017] [Accepted: 04/28/2017] [Indexed: 01/22/2023]
Abstract
Bacterial two-component systems consist of a sensor histidine kinase (HK) and a response regulator (RR). HKs are homodimers that catalyze the autophosphorylation of a histidine residue and the subsequent phosphoryl transfer to its RR partner, triggering an adaptive response. How the HK autokinase and phosphotransferase activities are coordinated remains unclear. Here, we report X-ray structures of the prototypical HK CpxA trapped as a hemi-phosphorylated dimer, and of the receiver domain from the RR partner, CpxR. Our results reveal that the two catalytic reactions can occur simultaneously, one in each protomer of the asymmetric CpxA dimer. Furthermore, the increase of autokinase activity in the presence of phosphotransfer-impaired CpxR put forward the idea of an allosteric switching mechanism, according to which CpxR binding to one CpxA protomer triggers autophosphorylation in the second protomer. The ensuing dynamical model provides a mechanistic explanation of how HKs can efficiently orchestrate two catalytic reactions involving large-scale protein motions.
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Affiliation(s)
- Ariel E Mechaly
- Institut Pasteur, Unité de Microbiologie Structurale, CNRS UMR 3528 & Université Paris Diderot, Sorbonne Paris Cité, 25 rue du Dr. Roux, 75724, Paris Cedex 15, France.
| | - Silvia Soto Diaz
- Institut Pasteur, Unité de Microbiologie Structurale, CNRS UMR 3528 & Université Paris Diderot, Sorbonne Paris Cité, 25 rue du Dr. Roux, 75724, Paris Cedex 15, France
| | - Nathalie Sassoon
- Institut Pasteur, Unité de Microbiologie Structurale, CNRS UMR 3528 & Université Paris Diderot, Sorbonne Paris Cité, 25 rue du Dr. Roux, 75724, Paris Cedex 15, France
| | - Alejandro Buschiazzo
- Institut Pasteur de Montevideo, Laboratory of Molecular and Structural Microbiology, Montevideo 11400, Uruguay
| | - Jean-Michel Betton
- Institut Pasteur, Unité de Microbiologie Structurale, CNRS UMR 3528 & Université Paris Diderot, Sorbonne Paris Cité, 25 rue du Dr. Roux, 75724, Paris Cedex 15, France
| | - Pedro M Alzari
- Institut Pasteur, Unité de Microbiologie Structurale, CNRS UMR 3528 & Université Paris Diderot, Sorbonne Paris Cité, 25 rue du Dr. Roux, 75724, Paris Cedex 15, France.
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8
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Virus-like particles from Escherichia Coli-derived untagged papaya ringspot virus capsid protein purified by immobilized metal affinity chromatography enhance the antibody response against a soluble antigen. Mol Biotechnol 2016; 56:1110-20. [PMID: 25119647 DOI: 10.1007/s12033-014-9791-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
There is a growing interest in using virus-like particles (VLPs) as scaffolds for the presentation of antigens of choice to the immune system. In this work, VLPs from papaya ringspot virus capsid protein expressed in Escherichia coli were evaluated as enhancers of antibody response against a soluble antigen. Interestingly, although the capsid protein lacks a histidine tag, its purification by immobilized metal affinity chromatography was achieved. The formation of VLPs was demonstrated by electron microscopy for the first time for this capsid protein. VLPs were enriched by polyethylene glycol precipitation. Additionally, these VLPs were chemically coupled to green fluorescent protein in order to evaluate them as antigen carriers; however, bioconjugate instability was observed. Nonetheless, the adjuvant effect of these VLPs on BALB/c mice was evaluated, using GFP as antigen, resulting in a significant increase in anti-GFP IgG response, particularly, IgG1 class, demonstrating that the VLPs enhance the immune response against the antigen chosen in this study.
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Abstract
Members of the ABC-F subfamily of ATP-binding cassette proteins mediate resistance to a broad array of clinically important antibiotic classes that target the ribosome of Gram-positive pathogens. The mechanism by which these proteins act has been a subject of long-standing controversy, with two competing hypotheses each having gained considerable support: antibiotic efflux versus ribosomal protection. Here, we report on studies employing a combination of bacteriological and biochemical techniques to unravel the mechanism of resistance of these proteins, and provide several lines of evidence that together offer clear support to the ribosomal protection hypothesis. Of particular note, we show that addition of purified ABC-F proteins to an in vitro translation assay prompts dose-dependent rescue of translation, and demonstrate that such proteins are capable of displacing antibiotic from the ribosome in vitro. To our knowledge, these experiments constitute the first direct evidence that ABC-F proteins mediate antibiotic resistance through ribosomal protection. Antimicrobial resistance ranks among the greatest threats currently facing human health. Elucidation of the mechanisms by which microorganisms resist the effect of antibiotics is central to understanding the biology of this phenomenon and has the potential to inform the development of new drugs capable of blocking or circumventing resistance. Members of the ABC-F family, which include lsa(A), msr(A), optr(A), and vga(A), collectively yield resistance to a broader range of clinically significant antibiotic classes than any other family of resistance determinants, although their mechanism of action has been controversial since their discovery 25 years ago. Here we present the first direct evidence that proteins of the ABC-F family act to protect the bacterial ribosome from antibiotic-mediated inhibition.
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Ishido T, Yamazaki N, Ishikawa M, Hirano K. Characterization of DNA polymerase β from Danio rerio by overexpression in E. coli using the in vivo/in vitro compatible pIVEX plasmid. Microb Cell Fact 2011; 10:84. [PMID: 22018137 PMCID: PMC3214136 DOI: 10.1186/1475-2859-10-84] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 10/21/2011] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Eukaryotic DNA polymerase β (pol β), the polymerase thought to be responsible for DNA repair synthesis, has been extensively characterized in rats and humans. However, pol β has not been purified or enzymatically characterized from the model fish species Danio rerio (zebrafish). We used the in vitro/in vivo dual expression system plasmid, pIVEX, to express Danio rerio pol β (Danio pol β) for biochemical characterization. RESULTS Danio pol β encoded by the in vitro/in vivo-compatible pIVEX plasmid was expressed in E. coli BL21(DE3), BL21(DE3)pLysS, and KRX, and in vitro as a C-terminal His-tagged protein. Danio pol β expressed in vitro was subject to proteolysis; therefore, bacterial overexpression was used to produce the protein for kinetic analyses. KRX cells were preferred because of their reduced propensity for leaky expression of pol β. The cDNA of Danio rerio pol β encodes a protein of 337 amino acids, which is 2-3 amino acids longer than other pol β proteins, and contains a P63D amino acid substitution, unlike mammalian pol βs. This substitution lies in a hairpin sequence within an 8-kDa domain, likely to be important in DNA binding. We performed extensive biochemical characterization of Danio pol β in comparison with rat pol β, which revealed its sensitivity to metal ion activators (Mn2+ and Mg2+), its optimum salt concentration (10 mM KCl and 50 mM NaCl), alkaline pH optimum (pH 9.0), and low temperature optimum (30°C). Substituting Mn2+ for Mg2+ resulted in 8.6-fold higher catalytic efficiency (kcat/Km). CONCLUSIONS Our characterization of pol β from a model fish organism contributes to the study of the function and evolution of DNA polymerases, which are emerging as important cellular targets for chemical intervention in the development of anticancer agents.
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Affiliation(s)
- Tomomi Ishido
- Health Research Institute, National Institute of Advanced Industrial Science and Technology, Takamatsu, Kagawa, Japan
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The minor pilin subunit Sgp2 is necessary for assembly of the pilus encoded by the srtG cluster of Streptococcus suis. J Bacteriol 2010; 193:822-31. [PMID: 21148736 DOI: 10.1128/jb.01555-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gram-positive pili are composed of covalently bound pilin subunits whose assembly is mediated via a pilus-specific sortase(s). Major subunits constitute the pilus backbone and are therefore essential for pilus formation. Minor subunits are also incorporated into the pilus, but they are considered to be dispensable for backbone formation. The srtG cluster is one of the putative pilus gene clusters identified in the major swine pathogen Streptococcus suis. It consists of one sortase gene (srtG) and two putative pilin subunit genes (sgp1 and sgp2). In this study, by constructing mutants for each of the genes in the cluster and by both immunoblotting and immunogold electron microscopic analysis with antibodies against Sgp1 and Sgp2, we found that the srtG cluster mediates the expression of pilus-like structures in S. suis strain 89/1591. In this pilus, Sgp1 forms the backbone, whereas Sgp2 is incorporated as the minor subunit. In accordance with the current model of pilus assembly by Gram-positive organisms, the major subunit Sgp1 was indispensable for backbone formation and the cognate sortase SrtG mediated the polymerization of both subunits. However, unlike other well-characterized Gram-positive bacterial pili, the minor subunit Sgp2 was required for polymerization of the major subunit Sgp1. Because Sgp2 homologues are encoded in several other Gram-positive bacterial pilus gene clusters, in some types of pili, minor pilin subunits may contribute to backbone formation by a novel mechanism.
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Fittipaldi N, Takamatsu D, Domínguez-Punaro MDLC, Lecours MP, Montpetit D, Osaki M, Sekizaki T, Gottschalk M. Mutations in the gene encoding the ancillary pilin subunit of the Streptococcus suis srtF cluster result in pili formed by the major subunit only. PLoS One 2010; 5:e8426. [PMID: 20052283 PMCID: PMC2797073 DOI: 10.1371/journal.pone.0008426] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Accepted: 12/01/2009] [Indexed: 01/03/2023] Open
Abstract
Pili have been shown to contribute to the virulence of different Gram-positive pathogenic species. Among other critical steps of bacterial pathogenesis, these structures participate in adherence to host cells, colonization and systemic virulence. Recently, the presence of at least four discrete gene clusters encoding putative pili has been revealed in the major swine pathogen and emerging zoonotic agent Streptococcus suis. However, pili production by this species has not yet been demonstrated. In this study, we investigated the functionality of one of these pili clusters, known as the srtF pilus cluster, by the construction of mutant strains for each of the four genes of the cluster as well as by the generation of antibodies against the putative pilin subunits. Results revealed that the S. suis serotype 2 strain P1/7, as well as several other highly virulent invasive S. suis serotype 2 isolates express pili from this cluster. However, in most cases tested, and as a result of nonsense mutations at the 5′ end of the gene encoding the minor pilin subunit (a putative adhesin), pili were formed by the major pilin subunit only. We then evaluated the role these pili play in S. suis virulence. Abolishment of the expression of srtF cluster-encoded pili did not result in impaired interactions of S. suis with porcine brain microvascular endothelial cells. Furthermore, non-piliated mutants were as virulent as the wild type strain when evaluated in a murine model of S. suis sepsis. Our results show that srtF cluster-encoded, S. suis pili are atypical compared to other Gram-positive pili. In addition, since the highly virulent strains under investigation are unlikely to produce other pili, our results suggest that pili might be dispensable for critical steps of the S. suis pathogenesis of infection.
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Affiliation(s)
- Nahuel Fittipaldi
- Groupe de Recherche sur les Maladies Infectieuses du Porc and Centre de Recherche en Infectiologie Porcine, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Canada
| | - Daisuke Takamatsu
- Research Team for Bacterial/Parasitic Diseases, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - María de la Cruz Domínguez-Punaro
- Groupe de Recherche sur les Maladies Infectieuses du Porc and Centre de Recherche en Infectiologie Porcine, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Canada
| | - Marie-Pier Lecours
- Groupe de Recherche sur les Maladies Infectieuses du Porc and Centre de Recherche en Infectiologie Porcine, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Canada
| | - Diane Montpetit
- Centre de Recherche et de Développement sur les Aliments, Agriculture et Agroalimentaire Canada, St-Hyacinthe, Canada
| | - Makoto Osaki
- Research Team for Bacterial/Parasitic Diseases, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Tsutomu Sekizaki
- Research Center for Food Safety, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Marcelo Gottschalk
- Groupe de Recherche sur les Maladies Infectieuses du Porc and Centre de Recherche en Infectiologie Porcine, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Canada
- * E-mail:
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Puertas JM, Betton JM. Engineering an efficient secretion of leech carboxypeptidase inhibitor in Escherichia coli. Microb Cell Fact 2009; 8:57. [PMID: 19874597 PMCID: PMC2775724 DOI: 10.1186/1475-2859-8-57] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Accepted: 10/29/2009] [Indexed: 11/11/2022] Open
Abstract
Background Despite advances in expression technologies, the efficient production of heterologous secreted proteins in Escherichia coli remains a challenge. One frequent limitation relies on their inability to be exported to the E. coli periplasm. However, recent studies have suggested that translational kinetics and signal sequences act in concert to modulate the export process. Results In order to produce leech carboxypeptidase inhibitor (LCI) in the bacterial periplasm, we compared expression of the natural and optimized gene sequences, and evaluated export efficiency of LCI fused to different signal sequences. The best combination of these factors acting on translation and export was obtained when the signal sequence of DsbA was fused to an E. coli codon-optimized mature LCI sequence. When tested in high cell density cultures, the protein was primarily found in the growth medium. Under these conditions, the engineered expression system yields over 470 mg.l-1 of purified active LCI. Conclusion These results support the hypothesis that heterologous secreted proteins require proper coupling between translation and translocation for optimal high-level production in E. coli.
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Affiliation(s)
- Juan-Miguel Puertas
- Unité de Biochimie Structurale, Institut Pasteur, URA-CNRS 2185, 75724 Paris Cedex 15, France.
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14
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De Felice M, Mattanovich D, Papagianni M, Wegrzyn G, Villaverde A. The scientific impact of microbial cell factories. Microb Cell Fact 2008; 7:33. [PMID: 19046424 PMCID: PMC2630955 DOI: 10.1186/1475-2859-7-33] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Accepted: 12/01/2008] [Indexed: 12/27/2022] Open
Affiliation(s)
- Maurilio De Felice
- Institute for Biotechnology and Biomedicine, Autonomous University of Barcelona, Barcelona, Spain.
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15
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Jacquet E, Girard JM, Ramaen O, Pamlard O, Lévaique H, Betton JM, Dassa E, Chesneau O. ATP hydrolysis and pristinamycin IIA inhibition of the Staphylococcus aureus Vga(A), a dual ABC protein involved in streptogramin A resistance. J Biol Chem 2008; 283:25332-25339. [PMID: 18562322 DOI: 10.1074/jbc.m800418200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In Gram-positive bacteria, a large subfamily of dual ATP-binding cassette proteins confers acquired or intrinsic resistance to macrolide, lincosamide, and streptogramin antibiotics by a far from well understood mechanism. Here, we report the first biochemical characterization of one such protein, Vga(A), which is involved in streptogramin A (SgA) resistance among staphylococci. Vga(A) is composed of two nucleotide-binding domains (NBDs), separated by a charged linker, with a C-terminal extension and without identified transmembrane domains. Highly purified Vga(A) displays a strong ATPase activity (K(m) = 78 mum, V(m) = 6.8 min(-1)) that was hardly inhibited by orthovanadate. Using mutants of the conserved catalytic glutamate residues, the two NBDs of Vga(A) were shown to contribute unequally to the total ATPase activity, the mutation at NBD2 being more detrimental than the other. ATPase activity of both catalytic sites was essential for Vga(A) biological function because each single Glu mutant was unable to confer SgA resistance in the staphylococcal host. Of great interest, Vga(A) ATPase was specifically inhibited in a non-competitive manner by the SgA substrate, pristinamycin IIA (PIIA). A deletion of the last 18 amino acids of Vga(A) slightly affected the ATPase activity without modifying the PIIA inhibition values. In contrast, this deletion reduced 4-fold the levels of SgA resistance. Altogether, our results suggest a role for the C terminus in regulation of the SgA antibiotic resistance mechanism conferred by Vga(A) and demonstrate that this dual ATP-binding cassette protein interacts directly and specifically with PIIA, its cognate substrate.
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Affiliation(s)
- Eric Jacquet
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, avenue de la Terrasse, Gif-sur-Yvette 91190 and the.
| | - Jean-Marie Girard
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, avenue de la Terrasse, Gif-sur-Yvette 91190 and the
| | - Odile Ramaen
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, avenue de la Terrasse, Gif-sur-Yvette 91190 and the
| | - Olivier Pamlard
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, avenue de la Terrasse, Gif-sur-Yvette 91190 and the
| | - Hélène Lévaique
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, avenue de la Terrasse, Gif-sur-Yvette 91190 and the
| | | | - Elie Dassa
- Unité des Membranes Bactériennes, Institut Pasteur, CNRS URA 2172, 25 rue du Docteur Roux, Paris 75724 Cedex 15, France
| | - Olivier Chesneau
- Unité des Membranes Bactériennes, Institut Pasteur, CNRS URA 2172, 25 rue du Docteur Roux, Paris 75724 Cedex 15, France
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16
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Pham VL, Cadel MS, Gouzy-Darmon C, Hanquez C, Beinfeld MC, Nicolas P, Etchebest C, Foulon T. Aminopeptidase B, a glucagon-processing enzyme: site directed mutagenesis of the Zn2+-binding motif and molecular modelling. BMC BIOCHEMISTRY 2007; 8:21. [PMID: 17974014 PMCID: PMC2241622 DOI: 10.1186/1471-2091-8-21] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 10/31/2007] [Indexed: 12/18/2022]
Abstract
BACKGROUND Aminopeptidase B (Ap-B; EC 3.4.11.6) catalyzes the cleavage of basic residues at the N-terminus of peptides and processes glucagon into miniglucagon. The enzyme exhibits, in vitro, a residual ability to hydrolyze leukotriene A4 into the pro-inflammatory lipid mediator leukotriene B4. The potential bi-functional nature of Ap-B is supported by close structural relationships with LTA4 hydrolase (LTA4H ; EC 3.3.2.6). A structure-function analysis is necessary for the detailed understanding of the enzymatic mechanisms of Ap-B and to design inhibitors, which could be used to determine the complete in vivo functions of the enzyme. RESULTS The rat Ap-B cDNA was expressed in E. coli and the purified recombinant enzyme was characterized. 18 mutants of the H325EXXHX18E348 Zn2+-binding motif were constructed and expressed. All mutations were found to abolish the aminopeptidase activity. A multiple alignment of 500 sequences of the M1 family of aminopeptidases was performed to identify 3 sub-families of exopeptidases and to build a structural model of Ap-B using the x-ray structure of LTA4H as a template. Although the 3D structures of the two enzymes resemble each other, they differ in certain details. The role that a loop, delimiting the active center of Ap-B, plays in discriminating basic substrates, as well as the function of consensus motifs, such as RNP1 and Armadillo domain are discussed. Examination of electrostatic potentials and hydrophobic patches revealed important differences between Ap-B and LTA4H and suggests that Ap-B is involved in protein-protein interactions. CONCLUSION Alignment of the primary structures of the M1 family members clearly demonstrates the existence of different sub-families and highlights crucial residues in the enzymatic activity of the whole family. E. coli recombinant enzyme and Ap-B structural model constitute powerful tools for investigating the importance and possible roles of these conserved residues in Ap-B, LTA4H and M1 aminopeptidase catalytic sites and to gain new insight into their physiological functions. Analysis of Ap-B structural model indicates that several interactions between Ap-B and proteins can occur and suggests that endopeptidases might form a complex with Ap-B during hormone processing.
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Affiliation(s)
- Viet-Laï Pham
- Université Pierre et Marie Curie-Paris6, FRE 2852 (CNRS), Protéines : Biochimie Structurale et Fonctionnelle, Structures et Fonctions des Aminopeptidases, Paris, F-75005 France
| | - Marie-Sandrine Cadel
- Université Pierre et Marie Curie-Paris6, FRE 2852 (CNRS), Protéines : Biochimie Structurale et Fonctionnelle, Structures et Fonctions des Aminopeptidases, Paris, F-75005 France
| | - Cécile Gouzy-Darmon
- Université Pierre et Marie Curie-Paris6, FRE 2852 (CNRS), Protéines : Biochimie Structurale et Fonctionnelle, Structures et Fonctions des Aminopeptidases, Paris, F-75005 France
| | - Chantal Hanquez
- Université Pierre et Marie Curie-Paris6, FRE 2852 (CNRS), Protéines : Biochimie Structurale et Fonctionnelle, Structures et Fonctions des Aminopeptidases, Paris, F-75005 France
| | - Margery C Beinfeld
- Department of Pharmacology and Experimental Therapeutics, Tufts University, School of Medicine, Boston, MA 02111, USA
| | - Pierre Nicolas
- Université Pierre et Marie Curie-Paris6, FRE 2852 (CNRS), Protéines : Biochimie Structurale et Fonctionnelle, Structures et Fonctions des Aminopeptidases, Paris, F-75005 France
| | - Catherine Etchebest
- Université Denis Diderot-Paris7, UMR S 726, INSERM, Laboratoire de Bioinformatique Génomique et Moléculaire, Paris, F-75251 France
| | - Thierry Foulon
- Université Pierre et Marie Curie-Paris6, FRE 2852 (CNRS), Protéines : Biochimie Structurale et Fonctionnelle, Structures et Fonctions des Aminopeptidases, Paris, F-75005 France
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