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Zhu D, Fan Y, Wang X, Li P, Huang Y, Jiao J, Zhao C, Li Y, Wang S, Du X. Characterization of Molecular Chaperone GroEL as a Potential Virulence Factor in Cronobacter sakazakii. Foods 2023; 12:3404. [PMID: 37761113 PMCID: PMC10528849 DOI: 10.3390/foods12183404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
The molecular chaperone GroEL of C. sakazakii, a highly conserved protein encoded by the gene grol, has the basic function of responding to heat shock, thus enhancing the bacterium's adaptation to dry and high-temperature environments, which poses a threat to food safety and human health. Our previous study demonstrated that GroEL was found in the bacterial membrane fraction and caused a strong immune response in C. sakazakii. In this study, we tried to elucidate the subcellular location and virulent effects of GroEL. In live C. sakazakii cells, GroEL existed in both the soluble and insoluble fractions. To study the secretory mechanism of GroEL protein, a non-reduced Western immunoblot was used to analyze the form of the protein, and the result showed that the exported GroEL protein was mainly in monomeric form. The exported GroEL could also be located on bacterial surface. To further research the virulent effect of C. sakazakii GroEL, an indirect immunofluorescence assay was used to detect the adhesion of recombinant GroEL protein to HCT-8 cells. The results indicated that the recombinant GroEL protein could adhere to HCT-8 cells in a short period of time. The recombinant GroEL protein could activate the NF-κB signaling pathway to release more pro-inflammatory cytokines (TNF-α, IL-6 and IL-8), downregulating the expression of tight-junction proteins (claudin-1, occluding, ZO-1 and ZO-2), which collectively resulted in dose-dependent virulent effects on host cells. Inhibition of the grol gene expression resulted in a significant decrease in bacterial adhesion to and invasion of HCT-8 cells. Moreover, the deficient GroEL also caused slow growth, decreased biofilm formation, defective motility and abnormal filamentation of the bacteria. In brief, C. sakazakii GroEL was an important virulence factor. This protein was not only crucial for the physiological activity of C. sakazakii but could also be secreted to enhance the bacterium's adhesion and invasion capabilities.
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Affiliation(s)
- Dongdong Zhu
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Yufei Fan
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Xiaoyi Wang
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Ping Li
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Yaping Huang
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Jingbo Jiao
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Chumin Zhao
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Yue Li
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
| | - Shuo Wang
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin 300071, China
| | - Xinjun Du
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China; (D.Z.); (Y.F.); (X.W.); (P.L.); (Y.H.); (J.J.); (C.Z.); (Y.L.); (S.W.)
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2
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Genome-wide CRISPRi screen identifies enhanced autolithotrophic phenotypes in acetogenic bacterium Eubacterium limosum. Proc Natl Acad Sci U S A 2023; 120:e2216244120. [PMID: 36716373 PMCID: PMC9963998 DOI: 10.1073/pnas.2216244120] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Acetogenic bacteria are a unique biocatalyst that highly promises to develop the sustainable bioconversion of carbon oxides (e.g., CO and CO2) into multicarbon biochemicals. Genotype-phenotype relationships are important for engineering their metabolic capability to enhance their biocatalytic performance; however, systemic investigation on the fitness contribution of individual gene has been limited. Here, we report genome-scale CRISPR interference screening using 41,939 guide RNAs designed from the E. limosum genome, one of the model acetogenic species, where all genes were targeted for transcriptional suppression. We investigated the fitness contributions of 96% of the total genes identified, revealing the gene fitness and essentiality for heterotrophic and autotrophic metabolisms. Our data show that the Wood-Ljungdahl pathway, membrane regeneration, membrane protein biosynthesis, and butyrate synthesis are essential for autotrophic acetogenesis in E. limosum. Furthermore, we discovered genes that are repression targets that unbiasedly increased autotrophic growth rates fourfold and acetoin production 1.5-fold compared to the wild-type strain under CO2-H2 conditions. These results provide insight for understanding acetogenic metabolism and genome engineering in acetogenic bacteria.
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Blackwood CB, Mateu-Borrás M, Sen-Kilic E, Pyles GM, Miller SJ, Weaver KL, Witt WT, Huckaby AB, Kang J, Chandler CE, Ernst RK, Heath Damron F, Barbier M. Bordetella pertussis whole cell immunization protects against Pseudomonas aeruginosa infections. NPJ Vaccines 2022; 7:143. [PMID: 36357402 PMCID: PMC9649022 DOI: 10.1038/s41541-022-00562-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 10/17/2022] [Indexed: 11/12/2022] Open
Abstract
Whole cell vaccines are complex mixtures of antigens, immunogens, and sometimes adjuvants that can trigger potent and protective immune responses. In some instances, such as whole cell Bordetella pertussis vaccination, the immune response to vaccination extends beyond the pathogen the vaccine was intended for and contributes to protection against other clinically significant pathogens. In this study, we describe how B. pertussis whole cell vaccination protects mice against acute pneumonia caused by Pseudomonas aeruginosa. Using ELISA and western blot, we identified that B. pertussis whole cell vaccination induces production of antibodies that bind to lab-adapted and clinical strains of P. aeruginosa, regardless of immunization route or adjuvant used. The cross-reactive antigens were identified using immunoprecipitation, mass spectrometry, and subsequent immunoblotting. We determined that B. pertussis GroEL and OmpA present in the B. pertussis whole cell vaccine led to production of antibodies against P. aeruginosa GroEL and OprF, respectively. Finally, we showed that recombinant B. pertussis OmpA was sufficient to induce protection against P. aeruginosa acute murine pneumonia. This study highlights the potential for use of B. pertussis OmpA as a vaccine antigen for prevention of P. aeruginosa infection, and the potential of broadly protective antigens for vaccine development.
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Affiliation(s)
- Catherine B. Blackwood
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - Margalida Mateu-Borrás
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - Emel Sen-Kilic
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - Gage M. Pyles
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - Sarah Jo Miller
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - Kelly L. Weaver
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - William T. Witt
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - Annalisa B. Huckaby
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - Jason Kang
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - Courtney E. Chandler
- grid.411024.20000 0001 2175 4264University of Maryland, Baltimore Department of Microbial Pathogenesis, School of Dentistry, 650 W. Baltimore St., Baltimore, MD 21201 USA
| | - Robert K. Ernst
- grid.411024.20000 0001 2175 4264University of Maryland, Baltimore Department of Microbial Pathogenesis, School of Dentistry, 650 W. Baltimore St., Baltimore, MD 21201 USA
| | - F. Heath Damron
- grid.268154.c0000 0001 2156 6140West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV 26505 USA
| | - Mariette Barbier
- West Virginia University Vaccine Development Center, Department of Microbiology, Immunology and Cell Biology, 64 Medical Center Drive, Morgantown, WV, 26505, USA.
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Kaderabkova N, Bharathwaj M, Furniss RCD, Gonzalez D, Palmer T, Mavridou DAI. The biogenesis of β-lactamase enzymes. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35943884 DOI: 10.1099/mic.0.001217] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The discovery of penicillin by Alexander Fleming marked a new era for modern medicine, allowing not only the treatment of infectious diseases, but also the safe performance of life-saving interventions, like surgery and chemotherapy. Unfortunately, resistance against penicillin, as well as more complex β-lactam antibiotics, has rapidly emerged since the introduction of these drugs in the clinic, and is largely driven by a single type of extra-cytoplasmic proteins, hydrolytic enzymes called β-lactamases. While the structures, biochemistry and epidemiology of these resistance determinants have been extensively characterized, their biogenesis, a complex process including multiple steps and involving several fundamental biochemical pathways, is rarely discussed. In this review, we provide a comprehensive overview of the journey of β-lactamases, from the moment they exit the ribosomal channel until they reach their final cellular destination as folded and active enzymes.
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Affiliation(s)
- Nikol Kaderabkova
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Manasa Bharathwaj
- Centre to Impact AMR, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - R Christopher D Furniss
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Diego Gonzalez
- Laboratoire de Microbiologie, Institut de Biologie, Université de Neuchâtel, Neuchâtel, 2000, Switzerland
| | - Tracy Palmer
- Microbes in Health and Disease, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Despoina A I Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA.,John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, Texas, USA
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Rauch J, Barton J, Kwiatkowski M, Wunderlich M, Steffen P, Moderzynski K, Papp S, Höhn K, Schwanke H, Witt S, Richardt U, Mehlhoop U, Schlüter H, Pianka V, Fleischer B, Tappe D, Osterloh A. GroEL is an immunodominant surface-exposed antigen of Rickettsia typhi. PLoS One 2021; 16:e0253084. [PMID: 34111210 PMCID: PMC8191997 DOI: 10.1371/journal.pone.0253084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/28/2021] [Indexed: 11/26/2022] Open
Abstract
Rickettsioses are neglected and emerging potentially fatal febrile diseases that are caused by obligate intracellular bacteria, rickettsiae. Rickettsia (R.) typhi and R. prowazekii constitute the typhus group (TG) of rickettsiae and are the causative agents of endemic and epidemic typhus, respectively. We recently generated a monoclonal antibody (BNI52) against R. typhi. Characterization of BNI52 revealed that it specifically recognizes TG rickettsiae but not the members of the spotted fever group (SFG) rickettsiae. We further show that BNI52 binds to protein fragments of ±30 kDa that are exposed on the bacterial surface and also present in the periplasmic space. These protein fragments apparently derive from the cytosolic GroEL protein of R. typhi and are also recognized by antibodies in the sera from patients and infected mice. Furthermore, BNI52 opsonizes the bacteria for the uptake by antigen presenting cells (APC), indicating a contribution of GroEL-specific antibodies to protective immunity. Finally, it is interesting that the GroEL protein belongs to 32 proteins that are differentially downregulated by R. typhi after passage through immunodeficient BALB/c CB17 SCID mice. This could be a hint that the rickettsia GroEL protein may have immunomodulatory properties as shown for the homologous protein from several other bacteria, too. Overall, the results of this study provide evidence that GroEL represents an immunodominant antigen of TG rickettsiae that is recognized by the humoral immune response against these pathogens and that may be interesting as a vaccine candidate. Apart from that, the BNI52 antibody represents a new tool for specific detection of TG rickettsiae in various diagnostic and experimental setups.
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Affiliation(s)
- Jessica Rauch
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jessica Barton
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Malte Wunderlich
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Pascal Steffen
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Stefanie Papp
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Katharina Höhn
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Hella Schwanke
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Susanne Witt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ulricke Richardt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ute Mehlhoop
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Verena Pianka
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Dennis Tappe
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Anke Osterloh
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Jiang C, Wynne M, Huber D. How Quality Control Systems AID Sec-Dependent Protein Translocation. Front Mol Biosci 2021; 8:669376. [PMID: 33928127 PMCID: PMC8076867 DOI: 10.3389/fmolb.2021.669376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 03/17/2021] [Indexed: 02/01/2023] Open
Abstract
The evolutionarily conserved Sec machinery is responsible for transporting proteins across the cytoplasmic membrane. Protein substrates of the Sec machinery must be in an unfolded conformation in order to be translocated across (or inserted into) the cytoplasmic membrane. In bacteria, the requirement for unfolded proteins is strict: substrate proteins that fold (or misfold) prematurely in the cytoplasm prior to translocation become irreversibly trapped in the cytoplasm. Partially folded Sec substrate proteins and stalled ribosomes containing nascent Sec substrates can also inhibit translocation by blocking (i.e., “jamming”) the membrane-embedded Sec machinery. To avoid these issues, bacteria have evolved a complex network of quality control systems to ensure that Sec substrate proteins do not fold in the cytoplasm. This quality control network can be broken into three branches, for which we have defined the acronym “AID”: (i) avoidance of cytoplasmic intermediates through cotranslationally channeling newly synthesized Sec substrates to the Sec machinery; (ii) inhibition of folding Sec substrate proteins that transiently reside in the cytoplasm by molecular chaperones and the requirement for posttranslational modifications; (iii) destruction of products that could potentially inhibit translocation. In addition, several stress response pathways help to restore protein-folding homeostasis when environmental conditions that inhibit translocation overcome the AID quality control systems.
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Affiliation(s)
- Chen Jiang
- School of Biosciences and the Institute for Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Max Wynne
- School of Biosciences and the Institute for Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Damon Huber
- School of Biosciences and the Institute for Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
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7
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Loos MS, Ramakrishnan R, Vranken W, Tsirigotaki A, Tsare EP, Zorzini V, Geyter JD, Yuan B, Tsamardinos I, Klappa M, Schymkowitz J, Rousseau F, Karamanou S, Economou A. Structural Basis of the Subcellular Topology Landscape of Escherichia coli. Front Microbiol 2019; 10:1670. [PMID: 31404336 PMCID: PMC6677119 DOI: 10.3389/fmicb.2019.01670] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/08/2019] [Indexed: 11/21/2022] Open
Abstract
Cellular proteomes are distributed in multiple compartments: on DNA, ribosomes, on and inside membranes, or they become secreted. Structural properties that allow polypeptides to occupy subcellular niches, particularly to after crossing membranes, remain unclear. We compared intrinsic and extrinsic features in cytoplasmic and secreted polypeptides of the Escherichia coli K-12 proteome. Structural features between the cytoplasmome and secretome are sharply distinct, such that a signal peptide-agnostic machine learning tool distinguishes cytoplasmic from secreted proteins with 95.5% success. Cytoplasmic polypeptides are enriched in aliphatic, aromatic, charged and hydrophobic residues, unique folds and higher early folding propensities. Secretory polypeptides are enriched in polar/small amino acids, β folds, have higher backbone dynamics, higher disorder and contact order and are more often intrinsically disordered. These non-random distributions and experimental evidence imply that evolutionary pressure selected enhanced secretome flexibility, slow folding and looser structures, placing the secretome in a distinct protein class. These adaptations protect the secretome from premature folding during its cytoplasmic transit, optimize its lipid bilayer crossing and allowed it to acquire cell envelope specific chemistries. The latter may favor promiscuous multi-ligand binding, sensing of stress and cell envelope structure changes. In conclusion, enhanced flexibility, slow folding, looser structures and unique folds differentiate the secretome from the cytoplasmome. These findings have wide implications on the structural diversity and evolution of modern proteomes and the protein folding problem.
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Affiliation(s)
- Maria S Loos
- Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, Rega Institute, KU Leuven, Leuven, Belgium
| | - Reshmi Ramakrishnan
- Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, Rega Institute, KU Leuven, Leuven, Belgium.,VIB Switch Laboratory, Department for Cellular and Molecular Medicine, VIB-KU Leuven Center for Brain & Disease Research, KU Leuven, Leuven, Belgium
| | - Wim Vranken
- Interuniversity Institute of Bioinformatics in Brussels, Free University of Brussels, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel and Center for Structural Biology, Brussels, Belgium
| | - Alexandra Tsirigotaki
- Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, Rega Institute, KU Leuven, Leuven, Belgium
| | - Evrydiki-Pandora Tsare
- Metabolic Engineering & Systems Biology Laboratory, Institute of Chemical Engineering Sciences, Foundation for Research and Technology-Hellas, Patras, Greece
| | - Valentina Zorzini
- Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, Rega Institute, KU Leuven, Leuven, Belgium
| | - Jozefien De Geyter
- Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, Rega Institute, KU Leuven, Leuven, Belgium
| | - Biao Yuan
- Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, Rega Institute, KU Leuven, Leuven, Belgium
| | - Ioannis Tsamardinos
- Gnosis Data Analysis PC, Heraklion, Greece.,Department of Computer Science, University of Crete, Heraklion, Greece
| | - Maria Klappa
- Metabolic Engineering & Systems Biology Laboratory, Institute of Chemical Engineering Sciences, Foundation for Research and Technology-Hellas, Patras, Greece
| | - Joost Schymkowitz
- VIB Switch Laboratory, Department for Cellular and Molecular Medicine, VIB-KU Leuven Center for Brain & Disease Research, KU Leuven, Leuven, Belgium
| | - Frederic Rousseau
- VIB Switch Laboratory, Department for Cellular and Molecular Medicine, VIB-KU Leuven Center for Brain & Disease Research, KU Leuven, Leuven, Belgium
| | - Spyridoula Karamanou
- Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, Rega Institute, KU Leuven, Leuven, Belgium
| | - Anastassios Economou
- Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, Rega Institute, KU Leuven, Leuven, Belgium.,Gnosis Data Analysis PC, Heraklion, Greece
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8
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Impact of bacterial chaperonin GroEL–GroES on bacteriorhodopsin folding and membrane integration. BIOPHYSICS REPORTS 2019. [DOI: 10.1007/s41048-019-0090-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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9
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Seyed Hosseini Fin NA, Barshan-Tashnizi M, Sajjadi SM, Asgari S, Mohajerani N, Mirzahoseini H. The effects of overexpression of cytoplasmic chaperones on secretory production of hirudin-PA in E. coli. Protein Expr Purif 2019; 157:42-49. [PMID: 30708036 DOI: 10.1016/j.pep.2019.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/25/2019] [Accepted: 01/28/2019] [Indexed: 11/18/2022]
Abstract
The secretory production of heterologous proteins in E. coli has revolutionized biotechnology. Efficient periplasmic production of foreign proteins in E. coli often requires a signal peptide to direct proteins to the periplasm. However, the presence of attached signal peptide does not guarantee periplasmic expression of target proteins. Overproduction of auxiliary proteins, such as chaperones can be a useful approach to enhance protein export. In the current study, three chaperone plasmid sets, including GroEL-GroES (GroELS), Dnak-Dnaj-GrpE (DnaKJE), and trigger factor (TF), were coexpressed in E. coli BL21 (DE3) in a pairwise manner with two pET22-b vectors carrying the recombinant hirudin-PA (Hir) gene and different signal sequences alkaline phosphatase (PhoA) and l-asparaginase II (l-ASP). Overexpression of cytoplasmic combinations of molecular chaperones containing GroELS and DnaKJE with PhoAHir increased the secretory production of PhoAHir by 2.6fold (p < 0.05) and 3.5fold (p < 0.01) compared with their controls, respectively. By contrast, secretory production of PhoAHir significantly reduced in the presence of overexpressed TF (p = 0.02). Further, periplasmic expression of l-ASP was significantly increased only in the presence of DnaKJE (p = 0.04). These findings suggest that using molecular chaperones can be helpful for improving periplasmic expression of Hir. However, tagged signal peptides may affect the physicochemical properties and secondary and tertiary structures of mature Hir, which may alter their interactions with chaperones. Hence, using overexpressed chaperones has various effects on secretory production of PhoAHir and l-ASPHir.
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Affiliation(s)
| | - Mohammad Barshan-Tashnizi
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran.
| | - Seyed Mehdi Sajjadi
- Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand, Iran
| | - Saeme Asgari
- Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Nazanin Mohajerani
- Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Hasan Mirzahoseini
- Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
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10
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Growth phase-specific changes in the composition of E. coli transcription complexes. J Chromatogr B Analyt Technol Biomed Life Sci 2019; 1109:155-165. [PMID: 30785097 DOI: 10.1016/j.jchromb.2019.01.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/21/2019] [Accepted: 01/22/2019] [Indexed: 01/22/2023]
Abstract
In E. coli, a single oligomeric enzyme transcribes the genomic DNA, while multiple auxiliary proteins and regulatory RNA interact with the core RNA polymerase (RP) during different stages of the transcription cycle to influence its function. In this work, using fast protein isolation techniques combined with mass spectrometry (MS) and immuno-analyses, we studied growth phase-specific changes in the composition of E. coli transcription complexes. We show that RP isolated from actively growing cells is represented by prevalent double copy assemblies and single copy RP-RNA and RP-RNA-RapA complexes. We demonstrate that RpoD/σ70 obtained in fast purification protocols carries tightly associated RNA and show evidence pointing to a role of sigma-associated RNA in the formation of native RP-(RNA)-RpoD/σ70 (holoenzyme) complexes. We report that enzymes linked functionally to the metabolism of lipopolysaccharides co-purify with RP-RNA complexes and describe two classes of RP-associated molecules (phospholipids and putative phospholipid-rNT species). We hypothesize that these modifications could enable anchoring of RP-RNA and RNA in cell membranes. We also report that proteins loosely associated with ribosomes and degradosomes (S1, Hfq) co-purify with RP-RNA complexes isolated from actively growing cells - a result consistent with their proposed roles as adaptor-proteins. In contrast, GroEL, SecB, and SecA co-purified with RP obtained from cells harvested in early stationary phase. Our results demonstrate that fast, affinity chromatography-based isolation of large multi-protein assemblies in combination with MS can be used as a tool for analysis of their composition and the profiling of small protein-associated molecules (SPAM).
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Cebrián G, Condón S, Mañas P. Physiology of the Inactivation of Vegetative Bacteria by Thermal Treatments: Mode of Action, Influence of Environmental Factors and Inactivation Kinetics. Foods 2017; 6:E107. [PMID: 29189748 PMCID: PMC5742775 DOI: 10.3390/foods6120107] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/20/2017] [Accepted: 11/28/2017] [Indexed: 12/03/2022] Open
Abstract
Heat has been used extensively in the food industry as a preservation method, especially due to its ability to inactivate microorganisms present in foods. However, many aspects regarding the mechanisms of bacterial inactivation by heat and the factors affecting this process are still not fully understood. The purpose of this review is to offer a general overview of the most important aspects of the physiology of the inactivation or survival of microorganisms, particularly vegetative bacteria, submitted to heat treatments. This could help improve the design of current heat processes methods in order to apply milder and/or more effective treatments that could fulfill consumer requirements for fresh-like foods while maintaining the advantages of traditional heat treatments.
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Affiliation(s)
- Guillermo Cebrián
- Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, 50009 Zaragoza, Spain.
| | - Santiago Condón
- Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, 50009 Zaragoza, Spain.
| | - Pilar Mañas
- Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, 50009 Zaragoza, Spain.
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12
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Cui P, Li X, Zhu M, Wang B, Liu J, Chen H. Design, synthesis and antimicrobial activities of thiouracil derivatives containing triazolo-thiadiazole as SecA inhibitors. Eur J Med Chem 2016; 127:159-165. [PMID: 28039774 DOI: 10.1016/j.ejmech.2016.12.053] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 12/23/2016] [Accepted: 12/24/2016] [Indexed: 11/28/2022]
Abstract
A series of novel thiouracil derivatives containing a triazolo-thiadiazole moiety (7a-7l) have been synthesized by structural modifications on a lead SecA inhibitor, 2. All the compounds have been evaluated for their antibacterial activities against Bacillus amyloliquefaciens, Staphylococcus aureus, and Bacillus subtilis. Compounds 7d and 7g were also tested for their inhibitory activities against SecA ATPase due to their promising antimicrobial activities. The inhibitory activity of compound 7d was found to be higher than that of 2. Molecular docking work suggests that compound 7d might bind at a pocket close to the ATPase ATP-binding domain.
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Affiliation(s)
- Penglei Cui
- Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China; College of Science, Agricultural University of Hebei, Baoding 071001, China
| | - Xiaoliu Li
- Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China.
| | - Mengyuan Zhu
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302-4098, USA
| | - Binghe Wang
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302-4098, USA
| | - Jing Liu
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding 071001, China
| | - Hua Chen
- Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China.
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13
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Chi H, Wang X, Li J, Ren H, Huang F. Chaperonin-enhanced Escherichia coli cell-free expression of functional CXCR4. J Biotechnol 2016; 231:193-200. [PMID: 27316829 DOI: 10.1016/j.jbiotec.2016.06.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/23/2016] [Accepted: 06/13/2016] [Indexed: 11/15/2022]
Abstract
G protein-coupled receptors (GPCRs) are important therapeutic targets for a broad spectrum of diseases and disorders. Obtaining milligram quantities of functional receptors through the development of robust production methods are highly demanded to probe GPCR structure and functions. In this study, we analyzed synergies of the bacterial chaperonin GroEL-GroES and cell-free expression for the production of functionally folded C-X-C chemokine GPCR type 4 (CXCR4). The yield of soluble CXCR4 in the presence of detergent Brij-35 reached ∼1.1mg/ml. The chaperonin complex added was found to significantly enhance the productive folding of newly synthesized CXCR4, by increasing both the rate (∼30-fold) and the yield (∼1.3-fold) of folding over its spontaneous behavior. Meanwhile, the structural stability of CXCR4 was also improved with supplied GroEL-GroES, as was the soluble expression of biologically active CXCR4 with a ∼1.4-fold increase. The improved stability together with the higher ligand binding affinity suggests more efficient folding. The essential chaperonin GroEL was shown to be partially effective on its own, but for maximum efficiency both GroEL and its co-chaperonin GroES were necessary. The method reported here should prove generally useful for cell-free production of large amounts of natively folded GPCRs, and even other classes of membrane proteins.
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Affiliation(s)
- Haixia Chi
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, Qingdao 266580, PR China.
| | - Xiaoqiang Wang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, Qingdao 266580, PR China; College of Science, China University of Petroleum (East China), Qingdao 266580, PR China.
| | - Jiqiang Li
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, Qingdao 266580, PR China.
| | - Hao Ren
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, Qingdao 266580, PR China.
| | - Fang Huang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, Qingdao 266580, PR China.
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Chi H, Wang X, Li J, Ren H, Huang F. Folding of newly translated membrane protein CCR5 is assisted by the chaperonin GroEL-GroES. Sci Rep 2015; 5:17037. [PMID: 26585937 PMCID: PMC4653635 DOI: 10.1038/srep17037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/23/2015] [Indexed: 01/20/2023] Open
Abstract
The in vitro folding of newly translated human CC chemokine receptor type 5
(CCR5), which belongs to the physiologically important family of G protein-coupled
receptors (GPCRs), has been studied in a cell-free system supplemented with the
surfactant Brij-35. The freshly synthesized CCR5 can spontaneously fold into its
biologically active state but only slowly and inefficiently. However, on addition of
the GroEL-GroES molecular chaperone system, the folding of the nascent CCR5 was
significantly enhanced, as was the structural stability and functional expression of
the soluble form of CCR5. The chaperonin GroEL was partially effective on its own,
but for maximum efficiency both the GroEL and its GroES lid were necessary. These
results are direct evidence for chaperone-assisted membrane protein folding and
therefore demonstrate that GroEL-GroES may be implicated in the folding of membrane
proteins.
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Affiliation(s)
- Haixia Chi
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Xiaoqiang Wang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Jiqiang Li
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Hao Ren
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Fang Huang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
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Non-structural proteins P17 and P33 are involved in the assembly of the internal membrane-containing virus PRD1. Virology 2015; 482:225-33. [PMID: 25880114 DOI: 10.1016/j.virol.2015.03.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/30/2014] [Accepted: 03/22/2015] [Indexed: 11/24/2022]
Abstract
Bacteriophage PRD1, which has been studied intensively at the structural and functional levels, still has some gene products with unknown functions and certain aspects of the PRD1 assembly process have remained unsolved. In this study, we demonstrate that the phage-encoded non-structural proteins P17 and P33, either individually or together, complement the defect in a temperature-sensitive GroES mutant of Escherichia coli for host growth and PRD1 propagation. Confocal microscopy of fluorescent fusion proteins revealed co-localisation between P33 and P17 as well as between P33 and the host chaperonin GroEL. A fluorescence recovery after photobleaching assay demonstrated that the diffusion of the P33 fluorescent fusion protein was substantially slower in E. coli than theoretically calculated, presumably resulting from intermolecular interactions. Our results indicate that P33 and P17 function in procapsid assembly, possibly in association with the host chaperonin complex GroEL/GroES.
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Siewert C, Hess WR, Duduk B, Huettel B, Reinhardt R, Büttner C, Kube M. Complete genome determination and analysis of Acholeplasma oculi strain 19L, highlighting the loss of basic genetic features in the Acholeplasmataceae. BMC Genomics 2014; 15:931. [PMID: 25344468 PMCID: PMC4221730 DOI: 10.1186/1471-2164-15-931] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 09/25/2014] [Indexed: 11/17/2022] Open
Abstract
Background Acholeplasma oculi belongs to the Acholeplasmataceae family, comprising the genera Acholeplasma and ‘Candidatus Phytoplasma’. Acholeplasmas are ubiquitous saprophytic bacteria. Several isolates are derived from plants or animals, whereas phytoplasmas are characterised as intracellular parasitic pathogens of plant phloem and depend on insect vectors for their spread. The complete genome sequences for eight strains of this family have been resolved so far, all of which were determined depending on clone-based sequencing. Results The A. oculi strain 19L chromosome was sequenced using two independent approaches. The first approach comprised sequencing by synthesis (Illumina) in combination with Sanger sequencing, while single molecule real time sequencing (PacBio) was used in the second. The genome was determined to be 1,587,120 bp in size. Sequencing by synthesis resulted in six large genome fragments, while the single molecule real time sequencing approach yielded one circular chromosome sequence. High-quality sequences were obtained by both strategies differing in six positions, which are interpreted as reliable variations present in the culture population. Our genome analysis revealed 1,471 protein-coding genes and highlighted the absence of the F1FO-type Na+ ATPase system and GroEL/ES chaperone. Comparison of the four available Acholeplasma sequences revealed a core-genome encoding 703 proteins and a pan-genome of 2,867 proteins. Conclusions The application of two state-of-the-art sequencing technologies highlights the potential of single molecule real time sequencing for complete genome determination. Comparative genome analyses revealed that the process of losing particular basic genetic features during genome reduction occurs in both genera, as indicated for several phytoplasma strains and at least A. oculi. The loss of the F1FO-type Na+ ATPase system may separate Acholeplasmataceae from other Mollicutes, while the loss of those genes encoding the chaperone GroEL/ES is not a rare exception in this bacterial class. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-931) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | - Michael Kube
- Humboldt-Universität zu Berlin, Faculty of Life Science, Thaer-Institute, Division Phytomedicine, Lentzeallee 55/57, 14195 Berlin, Germany.
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Castanié-Cornet MP, Bruel N, Genevaux P. Chaperone networking facilitates protein targeting to the bacterial cytoplasmic membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1442-56. [PMID: 24269840 DOI: 10.1016/j.bbamcr.2013.11.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 11/10/2013] [Accepted: 11/13/2013] [Indexed: 12/22/2022]
Abstract
Nascent polypeptides emerging from the ribosome are assisted by a pool of molecular chaperones and targeting factors, which enable them to efficiently partition as cytosolic, integral membrane or exported proteins. Extensive genetic and biochemical analyses have significantly expanded our knowledge of chaperone tasking throughout this process. In bacteria, it is known that the folding of newly-synthesized cytosolic proteins is mainly orchestrated by three highly conserved molecular chaperones, namely Trigger Factor (TF), DnaK (HSP70) and GroEL (HSP60). Yet, it has been reported that these major chaperones are strongly involved in protein translocation pathways as well. This review describes such essential molecular chaperone functions, with emphasis on both the biogenesis of inner membrane proteins and the post-translational targeting of presecretory proteins to the Sec and the twin-arginine translocation (Tat) pathways. Critical interplay between TF, DnaK, GroEL and other molecular chaperones and targeting factors, including SecB, SecA, the signal recognition particle (SRP) and the redox enzyme maturation proteins (REMPs) is also discussed. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Marie-Pierre Castanié-Cornet
- Laboratoire de Microbiologie et Génétique Moléculaire (LMGM), Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse, France
| | - Nicolas Bruel
- Laboratoire de Microbiologie et Génétique Moléculaire (LMGM), Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse, France
| | - Pierre Genevaux
- Laboratoire de Microbiologie et Génétique Moléculaire (LMGM), Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse, France.
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18
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Seydlová G, Halada P, Fišer R, Toman O, Ulrych A, Svobodová J. DnaK and GroEL chaperones are recruited to the Bacillus subtilis membrane after short-term ethanol stress. J Appl Microbiol 2012; 112:765-74. [DOI: 10.1111/j.1365-2672.2012.05238.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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19
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Sun X, Yang XY, Yin XF, Yu G, Xiao CL, He X, He QY. Proteomic analysis of membrane proteins from Streptococcus pneumoniae with multiple separation methods plus high accuracy mass spectrometry. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2012; 15:683-94. [PMID: 21978396 DOI: 10.1089/omi.2010.0133] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract Streptococcus pneumoniae is a Gram-positive human pathogen that causes a variety of serious mucosal and invasive diseases in human. Bacterial membrane proteins play crucial roles in host-pathogen interactions and bacterial pathogenesis, and thus are potential drug targets or vaccine candidates. In this study, membranes from Streptococcus pneumoniae D39 were enriched by mechanical grinding and ultracentrifugation, and then the membrane proteins were extracted with trifluroethanol and chloroform. Around 60% of the extracted proteins were identified to be membrane proteins with 2-DE coupled with MALDI-MS/MS and 2D-LC-ESI-MS/MS. These identified membrane proteins can be functionally categorized into various groups involved in nutriment transport, signal transduction, protein folding or secretion, oxidation, carbohydrate metabolism, and other physiological processes. A protein interaction network was constructed for understanding the regulation relationship of the membrane proteins. This study represents the first global characterization of membrane proteome from Gram-positive streptococcus species of bacteria, providing valuable clues for further investigation aiming at identifying drug/vaccine targets for the bacterial infection.
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Affiliation(s)
- Xuesong Sun
- Institute of Life and Health Engineering/National Engineering & Research Center of Genetic Medicine, Jinan University, Guangzhou, People's Republic of China.
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The enolase of Borrelia burgdorferi is a plasminogen receptor released in outer membrane vesicles. Infect Immun 2011; 80:359-68. [PMID: 22083700 DOI: 10.1128/iai.05836-11] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The agent of Lyme disease, Borrelia burgdorferi, has a number of outer membrane proteins that are differentially regulated during its life cycle. In addition to their physiological functions in the organism, these proteins also likely serve different functions in invasiveness and immune evasion. In borreliae, as well as in other bacteria, a number of membrane proteins have been implicated in binding plasminogen. The activation and transformation of plasminogen into its proteolytically active form, plasmin, enhances the ability of the bacteria to disseminate in the host. Outer membrane vesicles of B. burgdorferi contain enolase, a glycolytic-cycle enzyme that catalyzes 2-phosphoglycerate to form phosphoenolpyruvate, which is also a known plasminogen receptor in Gram-positive bacteria. The enolase was cloned, expressed, purified, and used to generate rabbit antienolase serum. The enolase binds plasminogen in a lysine-dependent manner but not through ionic interactions. Although it is present in the outer membrane, microscopy and proteinase K treatment showed that enolase does not appear to be exposed on the surface. However, enolase in the outer membrane vesicles is accessible to proteolytic degradation by proteinase K. Samples from experimentally and tick-infected mice and rabbits as well as from Lyme disease patients exhibit recognition of enolase in serologic assays. Thus, this immunogenic plasminogen receptor released in outer membrane vesicles could be responsible for external proteolysis in the pericellular environment and have roles in nutrition and in enhancing dissemination.
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Traffic jam at the bacterial sec translocase: targeting the SecA nanomotor by small-molecule inhibitors. ACTA ACUST UNITED AC 2011; 18:685-98. [PMID: 21700205 DOI: 10.1016/j.chembiol.2011.04.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 04/27/2011] [Accepted: 04/28/2011] [Indexed: 11/20/2022]
Abstract
The rapid rise of drug-resistant bacteria is one of the most serious unmet medical needs facing the world. Despite this increasing problem of antibiotic resistance, the number of different antibiotics available for the treatment of serious infections is dwindling. Therefore, there is an urgent need for new antibacterial drugs, preferably with novel modes of action to potentially avoid cross-resistance with existing antibacterial agents. In recent years, increasing attention has been paid to bacterial protein secretion as a potential antibacterial target. Among the different protein secretion pathways that are present in bacterial pathogens, the general protein secretory (Sec) pathway is widely considered as an attractive target for antibacterial therapy. One of the key components of the Sec pathway is the peripheral membrane ATPase SecA, which provides the energy for the translocation of preproteins across the bacterial cytoplasmic membrane. In this review, we will provide an overview of research efforts on the discovery and development of small-molecule SecA inhibitors. Furthermore, recent advances on the structure and function of SecA and their potential impact on antibacterial drug discovery will be discussed.
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22
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Activators of the glutamate-dependent acid resistance system alleviate deleterious effects of YidC depletion in Escherichia coli. J Bacteriol 2011; 193:1308-16. [PMID: 21216990 DOI: 10.1128/jb.01209-10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The function of the essential inner membrane protein (IMP) YidC in Escherichia coli has been studied for a limited number of model IMPs and primarily using targeted approaches. These studies suggested that YidC acts at the level of insertion, folding, and quality control of IMPs, both in the context of the Sec translocon and as a separate entity. To further our understanding of YidC's role in IMP biogenesis, we screened a random overexpression library for factors that rescued the growth of cells upon YidC depletion. We found that the overexpression of the GadX and GadY regulators of the glutamate-dependent acid resistance system complemented the growth defect of YidC-depleted cells. Evidence is presented that GadXY overexpression counteracts the deleterious effects of YidC depletion on at least two fronts. First, GadXY prepares the cells for the decrease in respiratory capacity upon the depletion of YidC. Most likely, GadXY-regulated processes reduce the drop in proton-motive force that impairs the fitness of YidC-depleted cells. Second, in GadXY-overproducing cells increased levels of the general chaperone GroEL cofractionate with the inner membranes, which may help to keep newly synthesized inner membrane proteins in an insertion-competent state when YidC levels are limiting.
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Wickström D, Wagner S, Baars L, Ytterberg AJ, Klepsch M, van Wijk KJ, Luirink J, de Gier JW. Consequences of depletion of the signal recognition particle in Escherichia coli. J Biol Chem 2010; 286:4598-609. [PMID: 20923772 DOI: 10.1074/jbc.m109.081935] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thus far, the role of the Escherichia coli signal recognition particle (SRP) has only been studied using targeted approaches. It has been shown for a handful of cytoplasmic membrane proteins that their insertion into the cytoplasmic membrane is at least partially SRP-dependent. Furthermore, it has been proposed that the SRP plays a role in preventing toxic accumulation of mistargeted cytoplasmic membrane proteins in the cytoplasm. To complement the targeted studies on SRP, we have studied the consequences of the depletion of the SRP component Fifty-four homologue (Ffh) in E. coli using a global approach. The steady-state proteomes and the proteome dynamics were evaluated using one- and two-dimensional gel analysis, followed by mass spectrometry-based protein identification and immunoblotting. Our analysis showed that depletion of Ffh led to the following: (i) impaired kinetics of the biogenesis of the cytoplasmic membrane proteome; (ii) lowered steady-state levels of the respiratory complexes NADH dehydrogenase, succinate dehydrogenase, and cytochrome bo(3) oxidase and lowered oxygen consumption rates; (iii) increased levels of the chaperones DnaK and GroEL at the cytoplasmic membrane; (iv) a σ(32) stress response and protein aggregation in the cytoplasm; and (v) impaired protein synthesis. Our study shows that in E. coli SRP-mediated protein targeting is directly linked to maintaining protein homeostasis and the general fitness of the cell.
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Affiliation(s)
- David Wickström
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm, Sweden
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Analysis of type II secretion of recombinant pneumococcal PspA and PspC in a Salmonella enterica serovar Typhimurium vaccine with regulated delayed antigen synthesis. Infect Immun 2008; 76:3241-54. [PMID: 18458067 DOI: 10.1128/iai.01623-07] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recombinant attenuated Salmonella vaccines (RASVs) have been used extensively to express and deliver heterologous antigens to host mucosal tissues. Immune responses can be enhanced greatly when the antigen is secreted to the periplasm or extracellular compartment. The most common method for accomplishing this is by fusion of the antigen to a secretion signal sequence. Finding an optimal signal sequence is typically done empirically. To facilitate this process, we constructed a series of plasmid expression vectors, each containing a different type II signal sequence. We evaluated the utilities of these vectors by fusing two different antigens, the alpha-helix domains of pneumococcal surface protein A (PspA) and pneumococcal surface protein C (PspC), to the signal sequences of beta-lactamase (bla SS), ompA, and phoA and the signal sequence and C-terminal peptide of beta-lactamase (bla SS+CT) on Asd(+) plasmids under the control of the P(trc) promoter. Strains were characterized for level of expression, subcellular antigen location, and the capacity to elicit antigen-specific immune responses and protection against challenge with Streptococcus pneumoniae in mice. The immune responses to each protein differed depending on the signal sequence used. Strains carrying the bla SS-pspA and bla SS+CT-pspC fusions yielded the largest amounts of secreted PspA and PspC, respectively, and induced the highest serum IgG titers, although all fusion proteins tested induced some level of antigen-specific IgG response. Consistent with the serum antibody responses, RASVs expressing the bla SS-pspA and bla SS+CT-pspC fusions induced the greatest protection against S. pneumoniae challenge.
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25
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Blencowe A, Blencowe C, Cosstick K, Hayes W. A carbene insertion approach to functionalised poly(ethylene oxide)-based gels. REACT FUNCT POLYM 2008. [DOI: 10.1016/j.reactfunctpolym.2007.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Lim JY, Sheng H, Seo KS, Park YH, Hovde CJ. Characterization of an Escherichia coli O157:H7 plasmid O157 deletion mutant and its survival and persistence in cattle. Appl Environ Microbiol 2007; 73:2037-47. [PMID: 17277224 PMCID: PMC1855633 DOI: 10.1128/aem.02643-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Escherichia coli O157:H7 causes hemorrhagic colitis and hemolytic-uremic syndrome in humans, and its major reservoir is healthy cattle. An F-like 92-kb plasmid, pO157, is found in most E. coli O157:H7 clinical isolates, and pO157 shares sequence similarities with plasmids present in other enterohemorrhagic E. coli serotypes. We compared wild-type (WT) E. coli O157:H7 and an isogenic DeltapO157 mutant for (i) growth rates and antibiotic susceptibilities, (ii) survival in environments with various acidity, salt, or heat conditions, (iii) protein expression, and (iv) survival and persistence in cattle following oral challenge. Growth, metabolic reactions, and antibiotic resistance of the DeltapO157 mutant were indistinguishable from those of its complement and the WT. However, in cell competition assays, the WT was more abundant than the DeltapO157 mutant. The DeltapO157 mutant was more resistant to acidic synthetic bovine gastric fluid and bile than the WT. In vivo, the DeltapO157 mutant survived passage through the bovine gastrointestinal tract better than the WT but, interestingly, did not colonize the bovine rectoanal junction mucosa as well as the WT. Many proteins were differentially expressed between the DeltapO157 mutant and the WT. Proteins from whole-cell lysates and membrane fractions of cell lysates were separated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis. Ten differentially expressed approximately 50-kDa proteins were identified by quadrupole-time of flight mass spectrometry and sequence matching with the peptide fragment database. Most of these proteins, including tryptophanase and glutamate decarboxylase isozymes, were related to survival under salvage conditions, and expression was increased by the deletion of pO157. This suggested that the genes on pO157 regulate some chromosomal genes.
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Affiliation(s)
- Ji Youn Lim
- Department of Microbiology, Molecular Biology, and Biochemistry, University of Idaho, Moscow, Idaho 83844-3052, USA
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27
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Robichon C, Dugail I. De novo cholesterol synthesis at the crossroads of adaptive response to extracellular stress through SREBP. Biochimie 2007; 89:260-4. [PMID: 17059860 DOI: 10.1016/j.biochi.2006.09.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Accepted: 09/21/2006] [Indexed: 11/25/2022]
Abstract
Cell sterol supply is subjected to tight negative feedback regulation through the SREBP pathway. Upon cholesterol depletion, SREBP transcription factors become activated by cleavage of a membrane bound precursor form, which stimulates the expression of the genes encoding proteins of the cholesterol synthesis pathway. In this paper, we discuss two situations of extracellular stress (hypoxia and heat shock) in which the cholesterol synthesis pathway and SREBPs are directly impacted to generate an adaptive response to cell damage. On one hand, the lack of oxygen in fission yeast Saccharomyces pombe induces a drop in cholesterol synthesis which in turn activates SREBP-mediated transcription. The presence of genes involved in the anaerobic growth program among SREBP target genes in fission yeast, indicates that SREBP behaves as an oxygen sensor, required for adaptive growth in low oxygen. On the other hand, upon heat shock in mammalian cells, SREBP-responsive heat shock proteins have been characterized, which were able to upregulate sterol synthesis by targeting the activity of HMG-CoA reductase, the rate limiting enzyme in this pathway. Although not yet proven, high rates of sterol synthesis can be viewed as an adaptive response to correct structural membrane damage and bilayer fluidification induced by thermal stress. Together these situations illustrate how the highly regulated SREBP pathway for the control of sterol synthesis can be used to achieve cell adaptive responses to extracellular stresses.
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28
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Zanen G, Antelmann H, Meima R, Jongbloed JDH, Kolkman M, Hecker M, van Dijl JM, Quax WJ. Proteomic dissection of potential signal recognition particle dependence in protein secretion by Bacillus subtilis. Proteomics 2006; 6:3636-48. [PMID: 16705751 DOI: 10.1002/pmic.200500560] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The bacterial signal recognition particle (SRP)-dependent pathway is believed to be a major targeting route for membrane proteins, as well as for subsets of secretory proteins. The present studies were aimed at an assessment of the role of two key components of SRP, namely Ffh and FtsY, in protein secretion by the Gram-positive bacterium Bacillus subtilis. Our results show that both components are important for the extracellular accumulation of proteins containing known signal peptides. Remarkably, extracellular accumulation of individual proteins was affected to different extents by depletion of Ffh or FtsY, at least under the conditions tested. Moreover, the observed Ffh or FtsY dependence of certain secretory proteins did not seem to correlate with signal peptide length or hydrophobicity. Although it is presently difficult to distinguish between direct and indirect effects, these findings suggest that other, yet unidentified, determinants in secretory proteins are also important for their SRP dependence. High-level production of homologous and heterologous secretory proteins was shown to result in elevated cellular Ffh and FtsY levels. This phenomenon is, most likely, due to post-transcriptional regulation. In conclusion, the present proteomic dissection of SRP-dependent extracellular protein accumulation provides exciting leads to identify novel determinants for interactions between secretory proteins and SRP.
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Affiliation(s)
- Geeske Zanen
- Department of Pharmaceutical Biology, University of Groningen, The Netherlands
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29
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Plesa M, Hernalsteens JP, Vandenbussche G, Ruysschaert JM, Cornelis P. The SlyB outer membrane lipoprotein of Burkholderia multivorans contributes to membrane integrity. Res Microbiol 2006; 157:582-92. [PMID: 16500084 DOI: 10.1016/j.resmic.2005.11.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 11/22/2005] [Accepted: 11/29/2005] [Indexed: 11/24/2022]
Abstract
SlyB is a small lipoprotein of 158 amino acids which is conserved in different Gram-negative bacteria. In contrast to other bacteria, where slyB is monocistronic, in Burkholderia multivorans and in B. cenocepacia, slyB is the last gene of an operon comprising three open reading frames encoding a putative thiol peroxidase, a putative sugar kinase and SlyB. B. multivorans slyB mutants produced elongated cells and filaments which were never observed in cultures of wild-type or slyB-complemented cells. The slyB mutant also showed increased sensitivity to EDTA and SDS, and decreased siderophore production. Proteome analysis of a fraction enriched for membrane proteins suggested that SlyB, like the peptidoglycan-associated protein OpcL, is a major protein of the outer membrane. Taken together, these phenotypes suggest that SlyB contributes to the integrity of the cell envelope. By PCR amplification we were also able to demonstrate the conservation of slyB in all B. cepacia complex species tested.
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Affiliation(s)
- Maria Plesa
- Flanders Interuniversity Institute of Biotechnology (VIB6), Laboratory of Microbial Interactions, Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Building E, room 6.6, Pleinlaan 2, B-1050 Brussels, Belgium
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30
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Ziedaite G, Daugelavicius R, Bamford JKH, Bamford DH. The Holin protein of bacteriophage PRD1 forms a pore for small-molecule and endolysin translocation. J Bacteriol 2005; 187:5397-405. [PMID: 16030234 PMCID: PMC1196050 DOI: 10.1128/jb.187.15.5397-5405.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PRD1 is a bacteriophage with an icosahedral outer protein layer surrounding the viral membrane, which encloses the linear double-stranded DNA genome. PRD1 infects gram-negative cells harboring a conjugative IncP plasmid. Here we studied the lytic functions of PRD1. Using infected cells and plasmid-borne lysis genes, we demonstrated that a two-component lysis system (holin-endolysin) operates to release progeny phage particles from the host cell. Monitoring of ion fluxes and the ATP content of the infected cells allowed us to build a model of the sequence of lysis-related physiological changes. A decrease in the intracellular level of ATP is the earliest indicator of cell lysis, followed by the leakage of K+ from the cytosol approximately 20 min prior to the decrease in culture turbidity. However, the K+ efflux does not immediately lead to the depolarization of the cytoplasmic membrane or leakage of the intracellular ATP. These effects are observed only approximately 5 to 10 min prior to cell lysis. Similar results were obtained using cells expressing the holin and endolysin genes from plasmids.
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Affiliation(s)
- Gabija Ziedaite
- Biocenter 2, P.O. Box 56 (Viikinkaari 5), FIN-00014 University of Helsinki, Finland
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31
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Blencowe A, Hayes W. Development and application of diazirines in biological and synthetic macromolecular systems. SOFT MATTER 2005; 1:178-205. [PMID: 32646075 DOI: 10.1039/b501989c] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Many different reagents and methodologies have been utilised for the modification of synthetic and biological macromolecular systems. In addition, an area of intense research at present is the construction of hybrid biosynthetic polymers, comprised of biologically active species immobilised or complexed with synthetic polymers. One of the most useful and widely applicable techniques available for functionalisation of macromolecular systems involves indiscriminate carbene insertion processes. The highly reactive and non-specific nature of carbenes has enabled a multitude of macromolecular structures to be functionalised without the need for specialised reagents or additives. The use of diazirines as stable carbene precursors has increased dramatically over the past twenty years and these reagents are fast becoming the most popular photophors for photoaffinity labelling and biological applications in which covalent modification of macromolecular structures is the basis to understanding structure-activity relationships. This review reports the synthesis and application of a diverse range of diazirines in macromolecular systems.
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Affiliation(s)
- Anton Blencowe
- School of Chemistry, The University of Reading, Whiteknights, Reading, Berkshire, UKRG6 6AD.
| | - Wayne Hayes
- School of Chemistry, The University of Reading, Whiteknights, Reading, Berkshire, UKRG6 6AD.
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32
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Nandakumar R, Nandakumar MP, Marten MR, Ross JM. Proteome analysis of membrane and cell wall associated proteins from Staphylococcus aureus. J Proteome Res 2005; 4:250-7. [PMID: 15822900 DOI: 10.1021/pr049866k] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pathogenesis of Staphylococcus aureus, an opportunistic human pathogen, is complex and involves many virulence factors including an array of surface proteins (adhesins) that promote bacterial interactions with extracellular matrix components. A better understanding of these interactions can be achieved by studying the expression of membrane and cell wall associated proteins using a proteome analysis approach. To accomplish this, our goal here was to construct a reference map of membrane and cell wall associated proteins for S. aureus. Various lytic and solubilization methods have been tested to identify a suitable methodology for detection of these proteins in two-dimensional electrophoresis (2DE). Results demonstrate that cell lysis with lysostaphin, which lyses staphylococcal peptidoglycan, followed by solubilization with urea, thiourea, amidosulfobetaine 14 (ASB 14) and dithiothreitol (DTT) is an effective method, yielding a sample comprising proteins of wide molecular ranges and isoelectric points with minimum contamination from cytosolic proteins. Mass spectrometric analysis was employed to identify the membrane and cell surface proteins present in the sample and consequently an initial proteomic map of membrane and cell wall associated proteins for S. aureus is presented.
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Affiliation(s)
- Renu Nandakumar
- Department of Chemical and Biochemical Engineering, University of Maryland Baltimore County, 1000 Hilltop circle, Baltimore, Maryland 21250, USA
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33
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Economou A. Sec, drugs and rock'n'roll: antibiotic targeting of bacterial protein translocation. Expert Opin Ther Targets 2005; 5:141-53. [PMID: 15992172 DOI: 10.1517/14728222.5.2.141] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A large number of bacterial proteins are active in extracytoplasmic locations. Targeting and membrane translocation of the vast majority of these secretory and membrane polypeptides is mediated by the Sec pathway. Protein secretion requires the co-ordinated and sequential action of targeting factors on the cis-side of the membrane, a complex membrane-embedded protein translocase and maturation enzymes on the trans-side. Recently, significant advances in the molecular genetics and biochemistry of the Sec pathway have revealed that several of the Sec pathway components are essential for bacterial viability and/or pathogenicity. Moreover, several biochemical assays and structural insights have become available. Importantly, some of the Sec components are unique to bacteria. These developments raise the possibility that the bacterial protein translocase and other Sec pathway components could become formidable targets for antibacterial drug discovery.
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Affiliation(s)
- A Economou
- Institute of Molecular Biology and Biotechnology, FORTH and Department of Biology, University of Crete, PO Box 1527, GR-711 10 Iraklio, Crete, Greece.
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34
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Fisher AC, DeLisa MP. A little help from my friends: quality control of presecretory proteins in bacteria. J Bacteriol 2004; 186:7467-73. [PMID: 15516557 PMCID: PMC524911 DOI: 10.1128/jb.186.22.7467-7473.2004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Adam C Fisher
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA
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35
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Deaton J, Sun J, Holzenburg A, Struck DK, Berry J, Young R. Functional bacteriorhodopsin is efficiently solubilized and delivered to membranes by the chaperonin GroEL. Proc Natl Acad Sci U S A 2004; 101:2281-6. [PMID: 14983001 PMCID: PMC356942 DOI: 10.1073/pnas.0307759100] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Soluble complexes between the tetradecameric chaperonin GroEL and integral membrane proteins can be efficiently formed by detergent dialysis. For example, GroEL14 was found to bind a limit of two molecules of bacteriorhodopsin (BR). The GroEL-solubilized BR molecules were rapidly ejected from the chaperonin complexes on the addition of ATP or adenosine 5'-[beta,gamma-imido]triphosphate but not AMP, indicating that conformational changes induced by nucleotide binding eliminate a binding site for the hydrophobic transmembrane domains. BR retains its native conformation in the GroEL complexes, as judged by the spectral characteristics of the bound retinal. Moreover, the chaperonin-solubilized BR could be transferred efficiently to liposomes and used to effect a light-driven proton gradient, indicating that both native conformation and vectorial insertion were accomplished. These results suggest new approaches to the study of purified integral membrane proteins in their natural membrane environment and raise the prospect that GroEL may have a role in the integration of proteins into the cytoplasmic membrane in vivo.
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Affiliation(s)
- John Deaton
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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36
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Drew D, Fröderberg L, Baars L, de Gier JWL. Assembly and overexpression of membrane proteins in Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1610:3-10. [PMID: 12586374 DOI: 10.1016/s0005-2736(02)00707-1] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The bacterium Escherichia coli is one of the most popular model systems to study the assembly of membrane proteins of the so-called helix-bundle class. Here, based on this system, we review and discuss what is currently known about the assembly of these membrane proteins. In addition, we will briefly review and discuss how E. coli has been used as a vehicle for the overexpression of membrane proteins.
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Affiliation(s)
- David Drew
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden
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37
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Abstract
Type I chaperonins play an essential role in the folding of newly translated and stress-denatured proteins in eubacteria, mitochondria and chloroplasts. Since their discovery, the bacterial chaperonins have provided an excellent model system for investigating the mechanism by which chaperonins mediate protein folding. Due to the high conservation of the primary sequence among Type I chaperonins, it is generally accepted that organellar chaperonins function similar to the bacterial ones. However, recent studies indicate that the chloroplast and mitochondrial chaperonins possess unique structural and functional properties that distinguish them from their bacterial homologs. This review focuses on the unique properties of organellar chaperonins.
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Affiliation(s)
- Galit Levy-Rimler
- Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69778, Tel Aviv, Israel
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38
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Abstract
For a long time, it was generally assumed that the biogenesis of inner membrane proteins in Escherichia coli occurs spontaneously, and that only the translocation of large periplasmic domains requires the aid of a protein machinery, the Sec translocon. However, evidence obtained in recent years indicates that most, if not all, inner membrane proteins require the assistance of protein factors to reach their native conformation in the membrane. Here, we review and discuss recent advances in our understanding of the biogenesis of inner membrane proteins in E. coli.
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Affiliation(s)
- J W de Gier
- Department of Biochemistry, Stockholm University, 106 91 Stockholm, Sweden.
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39
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Kim J, Kendall DA. Sec-dependent protein export and the involvement of the molecular chaperone SecB. Cell Stress Chaperones 2000; 5:267-75. [PMID: 11048650 PMCID: PMC312857 DOI: 10.1379/1466-1268(2000)005<0267:sdpeat>2.0.co;2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2000] [Revised: 06/12/2000] [Accepted: 06/13/2000] [Indexed: 11/24/2022] Open
Affiliation(s)
- Jinoh Kim
- Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut 06269, USA
| | - Debra A. Kendall
- Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut 06269, USA
- Correspondence to: Debra A. Kendall, Tel: 860 486-1891; Fax: 860 486-1784; .
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40
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Tjalsma H, Bolhuis A, Jongbloed JD, Bron S, van Dijl JM. Signal peptide-dependent protein transport in Bacillus subtilis: a genome-based survey of the secretome. Microbiol Mol Biol Rev 2000; 64:515-47. [PMID: 10974125 PMCID: PMC99003 DOI: 10.1128/mmbr.64.3.515-547.2000] [Citation(s) in RCA: 589] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
One of the most salient features of Bacillus subtilis and related bacilli is their natural capacity to secrete a variety of proteins into their environment, frequently to high concentrations. This has led to the commercial exploitation of bacilli as major "cell factories" for secreted enzymes. The recent sequencing of the genome of B. subtilis has provided major new impulse for analysis of the molecular mechanisms underlying protein secretion by this organism. Most importantly, the genome sequence has allowed predictions about the composition of the secretome, which includes both the pathways for protein transport and the secreted proteins. The present survey of the secretome describes four distinct pathways for protein export from the cytoplasm and approximately 300 proteins with the potential to be exported. By far the largest number of exported proteins are predicted to follow the major "Sec" pathway for protein secretion. In contrast, the twin-arginine translocation "Tat" pathway, a type IV prepilin-like export pathway for competence development, and ATP-binding cassette transporters can be regarded as "special-purpose" pathways, through which only a few proteins are transported. The properties of distinct classes of amino-terminal signal peptides, directing proteins into the various protein transport pathways, as well as the major components of each pathway are discussed. The predictions and comparisons in this review pinpoint important differences as well as similarities between protein transport systems in B. subtilis and other well-studied organisms, such as Escherichia coli and the yeast Saccharomyces cerevisiae. Thus, they may serve as a lead for future research and applications.
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Affiliation(s)
- H Tjalsma
- Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, 9750 AA Haren, The Netherlands
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41
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Abstract
SecA is an obligatory component of the complex hetero-septameric translocase of prokaryotes. It is unique in that it exists as two forms within the holoenzyme; first, as a structural component of the preprotein channel and second, as an ATP-dependent membrane cycling factor facilitating the translocation of a broad class of proteins across the cytoplasmic membrane. While the translocase activity of SecA appears to be functionally conserved, it is not clear whether the mechanisms of regulation of the secA gene are similarly maintained. The recent characterization of an ATP-dependent RNA helicase activity of SecA offers a unique mechanism for SecA to communicate the secretion status of the cell to the appropriate regulatory circuits simply by the unwinding of an appropriate RNA target. Resolution of these two activities through combined biochemical, genetic, and biophysical studies should lead to a better understanding of the role of SecA in bacterial secretion.
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Affiliation(s)
- M G Schmidt
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425-2230, USA
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42
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Abstract
Significant strides have been made during the past 20 years in our understanding of protein secretion across the bacterial inner membrane. Specialized chaperones select secretory polypeptide chains and usher them to a membrane-embedded preprotein translocase. This unique molecular machine envelops the polymeric substrate and migrates along its length in defined, energy-dependent steps. Consequently, preproteins are gradually pumped into the periplasm where they acquire their native, folded conformation.
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Affiliation(s)
- A Economou
- Institute of Molecular Biology and Biotechnology-FORTH, Iraklio, Crete, GR-71110, Greece.
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43
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Abstract
Proteins that perform their activity within the cytoplasmic membrane or outside this cell boundary must be targeted to the translocation site prior to their insertion and/or translocation. In bacteria, several targeting routes are known; the SecB- and the signal recognition particle-dependent pathways are the best characterized. Recently, evidence for the existence of a third major route, the twin-Arg pathway, was gathered. Proteins that use either one of these three different pathways possess special features that enable their specific interaction with the components of the targeting routes. Such targeting information is often contained in an N-terminal extension, the signal sequence, but can also be found within the mature domain of the targeted protein. Once the nascent chain starts to emerge from the ribosome, competition for the protein between different targeting factors begins. After recognition and binding, the targeting factor delivers the protein to the translocation sites at the cytoplasmic membrane. Only by means of a specific interaction between the targeting component and its receptor is the cargo released for further processing and translocation. This mechanism ensures the high-fidelity targeting of premembrane and membrane proteins to the translocation site.
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Affiliation(s)
- P Fekkes
- Department of Microbiology and Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9751 NN Haren, The Netherlands
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44
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Vigh L, Maresca B, Harwood JL. Does the membrane's physical state control the expression of heat shock and other genes? Trends Biochem Sci 1998; 23:369-74. [PMID: 9810221 DOI: 10.1016/s0968-0004(98)01279-1] [Citation(s) in RCA: 288] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Membranes provide the structural framework that divides cells from their environment and that, in eukaryotic cells, permits compartmentation. They are not simply passive barriers that are liable to be damaged during environmental challenge or pathological states, but are involved in cellular responses and in modulating intracellular signalling. Recent data show that the expression of several genes, particularly those that respond to changes in temperature, ageing or disease, is influenced and/or controlled by the membrane's physical state.
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Affiliation(s)
- L Vigh
- Hungarian Academy of Sciences, Biological Research Center, Szeged, Hungary
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