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Cianciotto NP. The type II secretion system as an underappreciated and understudied mediator of interbacterial antagonism. Infect Immun 2024; 92:e0020724. [PMID: 38980047 PMCID: PMC11320942 DOI: 10.1128/iai.00207-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024] Open
Abstract
Interbacterial antagonism involves all major phyla, occurs across the full range of ecological niches, and has great significance for the environment, clinical arena, and agricultural and industrial sectors. Though the earliest insight into interbacterial antagonism traces back to the discovery of antibiotics, a paradigm shift happened when it was learned that protein secretion systems (e.g., types VI and IV secretion systems) deliver toxic "effectors" against competitors. However, a link between interbacterial antagonism and the Gram-negative type II secretion system (T2SS), which exists in many pathogens and environmental species, is not evident in prior reviews on bacterial competition or T2SS function. A current examination of the literature revealed four examples of a T2SS or one of its known substrates having a bactericidal activity against a Gram-positive target or another Gram-negative. When further studied, the T2SS effectors proved to be peptidases that target the peptidoglycan of the competitor. There are also reports of various bacteriolytic enzymes occurring in the culture supernatants of some other Gram-negative species, and a link between these bactericidal activities and T2SS is suggested. Thus, a T2SS can be a mediator of interbacterial antagonism, and it is possible that many T2SSs have antibacterial outputs. Yet, at present, the T2SS remains relatively understudied for its role in interbacterial competition. Arguably, there is a need to analyze the T2SSs of a broader range of species for their role in interbacterial antagonism. Such investigation offers, among other things, a possible pathway toward developing new antimicrobials for treating disease.
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Affiliation(s)
- Nicholas P. Cianciotto
- Department of Microbiology-Immunology, Northwestern University School of Medicine, Chicago, Illinois, USA
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2
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Beriotto I, Icke C, Sevastsyanovich YR, Rossiter AE, Romagnoli G, Savino S, Hodges FJ, Cole JA, Saul A, MacLennan CA, Cunningham AF, Micoli F, Henderson IR. Efficient Autotransporter-Mediated Extracellular Secretion of a Heterologous Recombinant Protein by Escherichia coli. Microbiol Spectr 2023; 11:e0359422. [PMID: 37036352 PMCID: PMC10269718 DOI: 10.1128/spectrum.03594-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 03/20/2023] [Indexed: 04/11/2023] Open
Abstract
The autotransporter protein secretion system has been used previously to target the secretion of heterologous proteins to the bacterial cell surface and the extracellular milieu at the laboratory scale. The platform is of particular interest for the production of "difficult" recombinant proteins that might cause toxic effects when produced intracellularly. One such protein is IrmA. IrmA is a vaccine candidate that is produced in inclusion bodies requiring refolding. Here, we describe the use and scale-up of the autotransporter system for the secretion of an industrially relevant protein (IrmA). A plasmid expressing IrmA was constructed such that the autotransporter platform could secrete IrmA into the culture supernatant fraction. The autotransporter platform was suitable for the production and purification of IrmA with comparable physical properties to the protein produced in the cytoplasm. The production of IrmA was translated to scale-up protein production conditions resulting in a yield of 29.3 mg/L of IrmA from the culture supernatant, which is consistent with yields of current industrial processes. IMPORTANCE Recombinant protein production is an essential component of the biotechnology sector. Here, we show that the autotransporter platform is a viable method for the recombinant production, secretion, and purification of a "difficult" to produce protein on an industrially relevant scale. Use of the autotransporter platform could reduce the number of downstream processing operations required, thus accelerating the development time and reducing costs for recombinant protein production.
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Affiliation(s)
- Irene Beriotto
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
- GSK Vaccines Institute for Global Health Srl, Siena, Italy
| | - Christopher Icke
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | | | - Amanda E. Rossiter
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | | | - Silvana Savino
- GSK Vaccines Institute for Global Health Srl, Siena, Italy
| | - Freya J. Hodges
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Jeffrey A. Cole
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Allan Saul
- GSK Vaccines Institute for Global Health Srl, Siena, Italy
| | - Calman A. MacLennan
- GSK Vaccines Institute for Global Health Srl, Siena, Italy
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Adam F. Cunningham
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
- Institute for Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | | | - Ian R. Henderson
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
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Kavousipour S, Mohammadi S, Eftekhar E, Barazesh M, Morowvat MH. In Silico Investigation of Signal Peptide Sequences to Enhance Secretion of CD44 Nanobodies Expressed in Escherichia coli. Curr Pharm Biotechnol 2021; 22:1192-1205. [PMID: 33045964 DOI: 10.2174/1389201021666201012162904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/01/2020] [Accepted: 09/14/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND The selection of a suitable signal peptide that can direct recombinant proteins from the cytoplasm to the extracellular space is an important criterion affecting the production of recombinant proteins in Escherichia coli, a widely used host. Nanobodies are currently attracting the attention of scientists as antibody alternatives due to their specific properties and feasibility of production in E. coli. OBJECTIVE CD44 nanobodies constitute a potent therapeutic agent that can block CD44/HA interaction in cancer and inflammatory diseases. This molecule may also function as a drug against cancer cells and has been produced previously in E. coli without a signal peptide sequence. The goal of this project was to find a suitable signal peptide to direct CD44 nanobody extracellular secretion in E. coli that will potentially lead to optimization of experimental methods and facilitate downstream steps such as purification. METHODS We analyzed 40 E. coli derived signal peptides retrieved from the Signal Peptide database and selected the best candidate signal peptides according to relevant criteria including signal peptide probability, stability, and physicochemical features, which were evaluated using signalP software version 4.1 and the ProtParam tool, respectively. RESULTS In this in silico study, suitable candidate signal peptide(s) for CD44 nanobody secretory expression were identified. CSGA, TRBC, YTFQ, NIKA, and DGAL were selected as appropriate signal peptides with acceptable D-scores, and appropriate physicochemical and structural properties. Following further analysis, TRBC was selected as the best signal peptide to direct CD44 nanobody expression to the extracellular space of E. coli. CONCLUSION The selected signal peptide, TRBC is the most suitable to promote high-level secretory production of CD44 nanobodies in E. coli and potentially will be useful for scaling up CD44 nanobody production in experimental research as well as in other CD44 nanobody applications. However, experimental work is needed to confirm the data.
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Affiliation(s)
- Soudabeh Kavousipour
- Molecular Medicine Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Shiva Mohammadi
- Department of Biotechnology, School of Advanced Medical Science and Technologies, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Ebrahim Eftekhar
- Molecular Medicine Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Mahdi Barazesh
- School of Paramedical, Gerash University of Medical Sciences, Gerash, Iran
| | - Mohammad H Morowvat
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran P.O. Box 71468-64685, Shiraz, Iran
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Ageorges V, Monteiro R, Leroy S, Burgess CM, Pizza M, Chaucheyras-Durand F, Desvaux M. Molecular determinants of surface colonisation in diarrhoeagenic Escherichia coli (DEC): from bacterial adhesion to biofilm formation. FEMS Microbiol Rev 2021; 44:314-350. [PMID: 32239203 DOI: 10.1093/femsre/fuaa008] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/31/2020] [Indexed: 12/11/2022] Open
Abstract
Escherichia coli is primarily known as a commensal colonising the gastrointestinal tract of infants very early in life but some strains being responsible for diarrhoea, which can be especially severe in young children. Intestinal pathogenic E. coli include six pathotypes of diarrhoeagenic E. coli (DEC), namely, the (i) enterotoxigenic E. coli, (ii) enteroaggregative E. coli, (iii) enteropathogenic E. coli, (iv) enterohemorragic E. coli, (v) enteroinvasive E. coli and (vi) diffusely adherent E. coli. Prior to human infection, DEC can be found in natural environments, animal reservoirs, food processing environments and contaminated food matrices. From an ecophysiological point of view, DEC thus deal with very different biotopes and biocoenoses all along the food chain. In this context, this review focuses on the wide range of surface molecular determinants acting as surface colonisation factors (SCFs) in DEC. In the first instance, SCFs can be broadly discriminated into (i) extracellular polysaccharides, (ii) extracellular DNA and (iii) surface proteins. Surface proteins constitute the most diverse group of SCFs broadly discriminated into (i) monomeric SCFs, such as autotransporter (AT) adhesins, inverted ATs, heat-resistant agglutinins or some moonlighting proteins, (ii) oligomeric SCFs, namely, the trimeric ATs and (iii) supramolecular SCFs, including flagella and numerous pili, e.g. the injectisome, type 4 pili, curli chaperone-usher pili or conjugative pili. This review also details the gene regulatory network of these numerous SCFs at the various stages as it occurs from pre-transcriptional to post-translocational levels, which remains to be fully elucidated in many cases.
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Affiliation(s)
- Valentin Ageorges
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Ricardo Monteiro
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,GSK, Via Fiorentina 1, 53100 Siena, Italy
| | - Sabine Leroy
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Catherine M Burgess
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland
| | | | - Frédérique Chaucheyras-Durand
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,Lallemand Animal Nutrition SAS, F-31702 Blagnac Cedex, France
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
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Systematic Analysis of Escherichia coli Isolates from Sheep and Cattle Suggests Adaption to the Rumen Niche. Appl Environ Microbiol 2020; 86:AEM.01417-20. [PMID: 32801187 DOI: 10.1128/aem.01417-20] [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: 06/15/2020] [Accepted: 08/03/2020] [Indexed: 11/20/2022] Open
Abstract
The commonly used laboratory bacterium Escherichia coli normally does not produce and secrete cellulases due to its complex bilayer membrane structure and poor secretory apparatus. In our previous study, the cellulolytic E. coli strain ZH-4 with extracellular cellulase activity was found in the bovine rumen. In this study, we demonstrate that the secretion of cellulase is a common feature of E. coli isolates from the rumen of animals such as sheep and cattle. Physiological phenotype characterization of these E. coli isolates, together with genome, transcriptome, and comparative genomics analysis, suggests their adaption to the rumen niche. The higher growth rate of the isolated strains under aerobic conditions meets the competitive requirements of the strains in rumen microecosystem, while anaerobic accumulation of reduced H2 and succinate is hypothesized to be the results of adaptation to the rumen environment. Cellulase secretion increased significantly when the molecular chaperone genes ibpA and ibpB were overexpressed. This was also revealed by the transcriptomic data. A possible mechanism for cellulase secretion by E. coli isolates was proposed based on the transcriptomic data and molecular experiments.IMPORTANCE As an important intestinal microorganism, E. coli is present in the intestinal tract of animals and in many other environments. However, it normally does not produce and secret cellulases due to its complex bilayer membrane structure and poor secretory apparatus. Here, we proved that E. coli is widely present in the rumen of sheep and cattle. Systematic analysis of the isolates indicated that they have adapted to the rumen niche, with phenotypes that include secretion of cellulase and fermentative accumulation of succinate and H2 The finding that overexpression of small heat shock protein genes ibpA and ibpB could facilitate cellulase BcsZ secretion, which provides a possible insight into the protein secretion mechanism of rumen-colonizing E. coli.
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Tan YX, Peters DS, Walsh SI, Holcomb M, Santos-Martins D, Forli S, Romesberg FE. Initial Analysis of the Arylomycin D Antibiotics. JOURNAL OF NATURAL PRODUCTS 2020; 83:2112-2121. [PMID: 32614583 DOI: 10.1021/acs.jnatprod.9b01174] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The arylomycins are a class of natural product antibiotics that inhibit bacterial type I signal peptidase and are under development as therapeutics. Four classes of arylomycins are known, arylomycins A-D. Previously, we reported the synthesis and analysis of representatives of the A, B, and C classes and showed that their spectrum of activity has the potential to be much broader than originally assumed. Along with a comparison of the mechanism of acquired and innate resistance, this led us to suggest that the arylomycins are latent antibiotics, antibiotics that once possessed broad-spectrum activity, but which upon examination today, have only narrow spectrum activity due to prior selection for resistance in the course of the competition with other microorganisms that drove their evolution in the first place. Interestingly, actinocarbasin, the only identified member of the arylomycin D class, has been reported to have activity against MRSA. To confirm and understand this activity, several actinocarbasin derivatives were synthesized. We demonstrate that the previously reported structure of actinocarbasin is incorrect, identify what is likely the correct scaffold, confirm that scaffold has activity against MRSA, and determine the origin of this activity.
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Affiliation(s)
- Yun Xuan Tan
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - David S Peters
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Shawn I Walsh
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Matthew Holcomb
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Diogo Santos-Martins
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Stefano Forli
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Floyd E Romesberg
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
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7
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Differential homotypic and heterotypic interactions of antigen 43 (Ag43) variants in autotransporter-mediated bacterial autoaggregation. Sci Rep 2019; 9:11100. [PMID: 31367003 PMCID: PMC6668479 DOI: 10.1038/s41598-019-47608-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/18/2019] [Indexed: 12/18/2022] Open
Abstract
Antigen 43 (Ag43) is a cell-surface exposed protein of Escherichia coli secreted by the Type V, subtype a, secretion system (T5aSS) and belonging to the family of self-associating autotransporters (SAATs). These modular proteins, comprising a cleavable N-terminal signal peptide, a surface-exposed central passenger and an outer membrane C-terminal translocator, self-recognise in a Velcro-like handshake mechanism. A phylogenetic network analysis focusing on the passenger revealed for the first time that they actually distribute into four distinct classes, namely C1, C2, C3 and C4. Structural alignment and modelling analyses demonstrated these classes arose from shuffling of two different subdomains within the Ag43 passengers. Functional analyses revealed that homotypic interactions occur for all Ag43 classes but significant differences in the sedimentation kinetics and aggregation state were present when Ag43C3 was expressed. In contrast, heterotypic interaction occurred in a very limited number of cases. Single cell-force spectroscopy demonstrated the importance of specific as well as nonspecific interactions in mediating Ag43-Ag43 recognition. We propose that structural differences in the subdomains of the Ag43 classes account for different autoaggregation dynamics and propensities to co-interact.
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8
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In silico Analysis of Different Signal Peptides for the Excretory Production of Recombinant NS3-GP96 Fusion Protein in Escherichia coli. Int J Pept Res Ther 2018. [DOI: 10.1007/s10989-018-9775-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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9
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Rojas-Lopez M, Zorgani MA, Kelley LA, Bailly X, Kajava AV, Henderson IR, Polticelli F, Pizza M, Rosini R, Desvaux M. Identification of the Autochaperone Domain in the Type Va Secretion System (T5aSS): Prevalent Feature of Autotransporters with a β-Helical Passenger. Front Microbiol 2018; 8:2607. [PMID: 29375499 PMCID: PMC5767081 DOI: 10.3389/fmicb.2017.02607] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 12/14/2017] [Indexed: 11/29/2022] Open
Abstract
Autotransporters (ATs) belong to a family of modular proteins secreted by the Type V, subtype a, secretion system (T5aSS) and considered as an important source of virulence factors in lipopolysaccharidic diderm bacteria (archetypical Gram-negative bacteria). While exported by the Sec pathway, the ATs are further secreted across the outer membrane via their own C-terminal translocator forming a β-barrel, through which the rest of the protein, namely the passenger, can pass. In several ATs, an autochaperone domain (AC) present at the C-terminal region of the passenger and upstream of the translocator was demonstrated as strictly required for proper secretion and folding. However, considering it was functionally characterised and identified only in a handful of ATs, wariness recently fells on the commonality and conservation of this structural element in the T5aSS. To circumvent the issue of sequence divergence and taking advantage of the resolved three-dimensional structure of some ACs, identification of this domain was performed following structural alignment among all AT passengers experimentally resolved by crystallography before searching in a dataset of 1523 ATs. While demonstrating that the AC is indeed a conserved structure found in numerous ATs, phylogenetic analysis further revealed a distribution into deeply rooted branches, from which emerge 20 main clusters. Sequence analysis revealed that an AC could be identified in the large majority of SAATs (self-associating ATs) but not in any LEATs (lipase/esterase ATs) nor in some PATs (protease autotransporters) and PHATs (phosphatase/hydrolase ATs). Structural analysis indicated that an AC was present in passengers exhibiting single-stranded right-handed parallel β-helix, whatever the type of β-solenoid, but not with α-helical globular fold. From this investigation, the AC of type 1 appears as a prevalent and conserved structural element exclusively associated to β-helical AT passenger and should promote further studies about the protein secretion and folding via the T5aSS, especially toward α-helical AT passengers.
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Affiliation(s)
- Maricarmen Rojas-Lopez
- Université Clermont Auvergne, INRA, UMR454 MEDiS, Clermont-Ferrand, France.,GSK, Siena, Italy
| | - Mohamed A Zorgani
- Université Clermont Auvergne, INRA, UMR454 MEDiS, Clermont-Ferrand, France
| | - Lawrence A Kelley
- Structural Bioinformatics Group, Imperial College London, London, United Kingdom
| | - Xavier Bailly
- Institut National de la Recherche Agronomique, UR346 Epidémiologie Animale, Saint Genès Champanelle, France
| | - Andrey V Kajava
- CRBM UMR5237 CNRS, Institut de Biologie Computationnelle, Université Montpellier, Montpellier, France
| | - Ian R Henderson
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Fabio Polticelli
- Department of Sciences, National Institute of Nuclear Physics, Roma Tre University, Rome, Italy
| | | | | | - Mickaël Desvaux
- Université Clermont Auvergne, INRA, UMR454 MEDiS, Clermont-Ferrand, France
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Anti-Salmonella Activity Modulation of Mastoparan V1-A Wasp Venom Toxin-Using Protease Inhibitors, and Its Efficient Production via an Escherichia coli Secretion System. Toxins (Basel) 2017; 9:toxins9100321. [PMID: 29027924 PMCID: PMC5666368 DOI: 10.3390/toxins9100321] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 12/27/2022] Open
Abstract
A previous study highlighted that mastoparan V1 (MP-V1), a mastoparan from the venom of the social wasp Vespula vulgaris, is a potent antimicrobial peptide against Salmonella infection, which causes enteric diseases. However, there exist some limits for its practical application due to the loss of its activity in an increased bacterial density and the difficulty of its efficient production. In this study, we first modulated successfully the antimicrobial activity of synthetic MP-V1 against an increased Salmonella population using protease inhibitors, and developed an Escherichia coli secretion system efficiently producing active MP-V1. The protease inhibitors used, except pepstatin A, significantly increased the antimicrobial activity of the synthetic MP-V1 at minimum inhibitory concentrations (determined against 10⁶ cfu/mL of population) against an increased population (10⁸ cfu/mL) of three different Salmonella serotypes, Gallinarum, Typhimurium and Enteritidis. Meanwhile, the E. coli strain harboring OmpA SS::MP-V1 was identified to successfully secrete active MP-V1 into cell-free supernatant, whose antimicrobial activity disappeared in the increased population (10⁸ cfu/mL) of Salmonella Typhimurium recovered by adding a protease inhibitor cocktail. Therefore, it has been concluded that our challenge using the E. coli secretion system with the protease inhibitors is an attractive strategy for practical application of peptide toxins, such as MP-V1.
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Wang X, Han Q, Chen G, Zhang W, Liu W. A Putative Type II Secretion System Is Involved in Cellulose Utilization in Cytophaga hutchisonii. Front Microbiol 2017; 8:1482. [PMID: 28848505 PMCID: PMC5553014 DOI: 10.3389/fmicb.2017.01482] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/24/2017] [Indexed: 11/23/2022] Open
Abstract
Cytophaga hutchinsonii is a gliding cellulolytic bacterium that degrades cellulose in a substrate contact-dependent manner. Specific proteins are speculated to be translocated to its extracellular milieu or outer membrane surface to participate in adhesion to cellulose and further digestion. In this study, we show that three orthologous genes encoding the major components (T2S-D, -F, and -G) of type II secretion system (T2SS) are involved in cellulose degradation but not in cell motility. The individual disruption of the three t2s genes results in a significantly retarded growth on cellobiose, regenerated amorphous cellulose, and Avicel cellulose. Enzymatic analyses demonstrate that, whereas the endoglucanase activity of the t2s mutant cells is increased, the β-glucosidase activity is remarkably reduced compared to that of WT cells. Further analyses reveal that the t2s mutant cells not only exhibit a different profile of cellulose-bound outer membrane proteins from that of wild-type cells, but also display a significant decrease in their capability to adhere to cellulose. These results indicate that a functional link exits between the putative T2SS and cellulose utilization in C. hutchinsonii, and thus provide a conceptual framework to understand the unique strategy deployed by C. hutchinsonii to assimilate cellulose.
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Affiliation(s)
- Xia Wang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong UniversityJinan, China
| | - Qingqing Han
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong UniversityJinan, China
| | - Guanjun Chen
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong UniversityJinan, China
| | - Weixin Zhang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong UniversityJinan, China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong UniversityJinan, China
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12
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Origins of Yersinia pestis sensitivity to the arylomycin antibiotics and the inhibition of type I signal peptidase. Antimicrob Agents Chemother 2015; 59:3887-98. [PMID: 25896690 DOI: 10.1128/aac.00181-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/10/2015] [Indexed: 02/04/2023] Open
Abstract
Yersinia pestis is the etiologic agent of the plague. Reports of Y. pestis strains that are resistant to each of the currently approved first-line and prophylactic treatments point to the urgent need to develop novel antibiotics with activity against the pathogen. We previously reported that Y. pestis strain KIM6+, unlike most Enterobacteriaceae, is susceptible to the arylomycins, a novel class of natural-product lipopeptide antibiotics that inhibit signal peptidase I (SPase). In this study, we show that the arylomycin activity is conserved against a broad range of Y. pestis strains and confirm that it results from the inhibition of SPase. We next investigated the origins of this unique arylomycin sensitivity and found that it does not result from an increased affinity of the Y. pestis SPase for the antibiotic and that alterations to each component of the Y. pestis lipopolysaccharide-O antigen, core, and lipid A-make at most only a small contribution. Instead, the origins of the sensitivity can be traced to an increased dependence on SPase activity that results from high levels of protein secretion under physiological conditions. These results highlight the potential of targeting protein secretion in cases where there is a heavy reliance on this process and also have implications for the development of the arylomycins as an antibiotic with activity against Y. pestis and potentially other Gram-negative pathogens.
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13
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Oertel D, Schmitz S, Freudl R. A TatABC-type Tat translocase is required for unimpaired aerobic growth of Corynebacterium glutamicum ATCC13032. PLoS One 2015; 10:e0123413. [PMID: 25837592 PMCID: PMC4383559 DOI: 10.1371/journal.pone.0123413] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 02/27/2015] [Indexed: 11/30/2022] Open
Abstract
The twin-arginine translocation (Tat) system transports folded proteins across the cytoplasmic membrane of bacteria and the thylakoid membrane of plant chloroplasts. Escherichia coli and other Gram-negative bacteria possess a TatABC-type Tat translocase in which each of the three inner membrane proteins TatA, TatB, and TatC performs a mechanistically distinct function. In contrast, low-GC Gram-positive bacteria, such as Bacillus subtilis, use a TatAC-type minimal Tat translocase in which the TatB function is carried out by a bifunctional TatA. In high-GC Gram-positive Actinobacteria, such as Mycobacterium tuberculosis and Corynebacterium glutamicum, tatA, tatB, and tatC genes can be identified, suggesting that these organisms, just like E. coli, might use TatABC-type Tat translocases as well. However, since contrary to this view a previous study has suggested that C. glutamicum might in fact use a TatAC translocase with TatB only playing a minor role, we reexamined the requirement of TatB for Tat-dependent protein translocation in this microorganism. Under aerobic conditions, the misassembly of the Rieske iron-sulfur protein QcrA was identified as a major reason for the severe growth defect of Tat-defective C. glutamicum mutant strains. Furthermore, our results clearly show that TatB, besides TatA and TatC, is strictly required for unimpaired aerobic growth. In addition, TatB was also found to be essential for the secretion of a heterologous Tat-dependent model protein into the C. glutamicum culture supernatant. Together with our finding that expression of the C. glutamicum TatB in an E. coli ΔtatB mutant strain resulted in the formation of an active Tat translocase, our results clearly indicate that a TatABC translocase is used as the physiologically relevant functional unit for Tat-dependent protein translocation in C. glutamicum and, most likely, also in other TatB-containing Actinobacteria.
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Affiliation(s)
- Dan Oertel
- Institut für Bio- und Geowissenschaften 1, IBG1: Biotechnologie, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Sabrina Schmitz
- Institut für Bio- und Geowissenschaften 1, IBG1: Biotechnologie, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Roland Freudl
- Institut für Bio- und Geowissenschaften 1, IBG1: Biotechnologie, Forschungszentrum Jülich GmbH, Jülich, Germany
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Contribution of the multiple Type I signal peptidases to the secretome of Listeria monocytogenes: Deciphering their specificity for secreted exoproteins by exoproteomic analysis. J Proteomics 2015; 117:95-105. [DOI: 10.1016/j.jprot.2015.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 12/18/2014] [Accepted: 01/13/2015] [Indexed: 12/29/2022]
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15
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Zorgani MA, Patron K, Desvaux M. New insight in the structural features of haloadaptation in α-amylases from halophilic Archaea following homology modeling strategy: folded and stable conformation maintained through low hydrophobicity and highly negative charged surface. J Comput Aided Mol Des 2014; 28:721-34. [DOI: 10.1007/s10822-014-9754-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 05/16/2014] [Indexed: 11/24/2022]
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16
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Chang JH, Desveaux D, Creason AL. The ABCs and 123s of bacterial secretion systems in plant pathogenesis. ANNUAL REVIEW OF PHYTOPATHOLOGY 2014; 52:317-45. [PMID: 24906130 DOI: 10.1146/annurev-phyto-011014-015624] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Bacteria have many export and secretion systems that translocate cargo into and across biological membranes. Seven secretion systems contribute to pathogenicity by translocating proteinaceous cargos that can be released into the extracellular milieu or directly into recipient cells. In this review, we describe these secretion systems and how their complexities and functions reflect differences in the destinations, states, functions, and sizes of the translocated cargos as well as the architecture of the bacterial cell envelope. We examine the secretion systems from the perspective of pathogenic bacteria that proliferate within plant tissues and highlight examples of translocated proteins that contribute to the infection and disease of plant hosts.
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Affiliation(s)
- Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331; ,
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17
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Chagnot C, Zorgani MA, Astruc T, Desvaux M. Proteinaceous determinants of surface colonization in bacteria: bacterial adhesion and biofilm formation from a protein secretion perspective. Front Microbiol 2013; 4:303. [PMID: 24133488 PMCID: PMC3796261 DOI: 10.3389/fmicb.2013.00303] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/22/2013] [Indexed: 01/30/2023] Open
Abstract
Bacterial colonization of biotic or abiotic surfaces results from two quite distinct physiological processes, namely bacterial adhesion and biofilm formation. Broadly speaking, a biofilm is defined as the sessile development of microbial cells. Biofilm formation arises following bacterial adhesion but not all single bacterial cells adhering reversibly or irreversibly engage inexorably into a sessile mode of growth. Among molecular determinants promoting bacterial colonization, surface proteins are the most functionally diverse active components. To be present on the bacterial cell surface, though, a protein must be secreted in the first place. Considering the close association of secreted proteins with their cognate secretion systems, the secretome (which refers both to the secretion systems and their protein substrates) is a key concept to apprehend the protein secretion and related physiological functions. The protein secretion systems are here considered in light of the differences in the cell-envelope architecture between diderm-LPS (archetypal Gram-negative), monoderm (archetypal Gram-positive) and diderm-mycolate (archetypal acid-fast) bacteria. Besides, their cognate secreted proteins engaged in the bacterial colonization process are regarded from single protein to supramolecular protein structure as well as the non-classical protein secretion. This state-of-the-art on the complement of the secretome (the secretion systems and their cognate effectors) involved in the surface colonization process in diderm-LPS and monoderm bacteria paves the way for future research directions in the field.
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Affiliation(s)
- Caroline Chagnot
- UR454 Microbiologie, INRA Saint-Genès Champanelle, France ; UR370 Qualité des Produits Animaux, INRA Saint-Genès Champanelle, France
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18
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Thomas S, Holland IB, Schmitt L. The Type 1 secretion pathway - the hemolysin system and beyond. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1629-41. [PMID: 24129268 DOI: 10.1016/j.bbamcr.2013.09.017] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/21/2013] [Accepted: 09/23/2013] [Indexed: 12/27/2022]
Abstract
Type 1 secretion systems (T1SS) are wide-spread among Gram-negative bacteria. An important example is the secretion of the hemolytic toxin HlyA from uropathogenic strains. Secretion is achieved in a single step directly from the cytosol to the extracellular space. The translocation machinery is composed of three indispensable membrane proteins, two in the inner membrane, and the third in the outer membrane. The inner membrane proteins belong to the ABC transporter and membrane fusion protein families (MFPs), respectively, while the outer membrane component is a porin-like protein. Assembly of the three proteins is triggered by accumulation of the transport substrate (HlyA) in the cytoplasm, to form a continuous channel from the inner membrane, bridging the periplasm and finally to the exterior. Interestingly, the majority of substrates of T1SS contain all the information necessary for targeting the polypeptide to the translocation channel - a specific sequence at the extreme C-terminus. Here, we summarize our current knowledge of regulation, channel assembly, translocation of substrates, and in the case of the HlyA toxin, its interaction with host membranes. We try to provide a complete picture of structure function of the components of the translocation channel and their interaction with the substrate. Although we will place the emphasis on the paradigm of Type 1 secretion systems, the hemolysin A secretion machinery from E. coli, we also cover as completely as possible current knowledge of other examples of these fascinating translocation systems. 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)
- Sabrina Thomas
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr, 1, 40225 Düsseldorf, Germany
| | - I Barry Holland
- Institute of Genetics and Microbiology, CNRS UMR 8621, University Paris-Sud XI, Building 409, 91405 Orsay Cedex, France
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr, 1, 40225 Düsseldorf, Germany.
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Gillings MR. Evolutionary consequences of antibiotic use for the resistome, mobilome and microbial pangenome. Front Microbiol 2013; 4:4. [PMID: 23386843 PMCID: PMC3560386 DOI: 10.3389/fmicb.2013.00004] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 01/03/2013] [Indexed: 12/16/2022] Open
Abstract
The widespread use and abuse of antibiotic therapy has evolutionary and ecological consequences, some of which are only just beginning to be examined. One well known consequence is the fixation of mutations and lateral gene transfer (LGT) events that confer antibiotic resistance. Sequential selection events, driven by different classes of antibiotics, have resulted in the assembly of diverse resistance determinants and mobile DNAs into novel genetic elements of ever-growing complexity and flexibility. These novel plasmids, integrons, and genomic islands have now become fixed at high frequency in diverse cell lineages by human antibiotic use. Consequently they can be regarded as xenogenetic pollutants, analogous to xenobiotic compounds, but with the critical distinction that they replicate rather than degrade when released to pollute natural environments. Antibiotics themselves must also be regarded as pollutants, since human production overwhelms natural synthesis, and a major proportion of ingested antibiotic is excreted unchanged into waste streams. Such antibiotic pollutants have non-target effects, raising the general rates of mutation, recombination, and LGT in all the microbiome, and simultaneously providing the selective force to fix such changes. This has the consequence of recruiting more genes into the resistome and mobilome, and of increasing the overlap between these two components of microbial genomes. Thus the human use and environmental release of antibiotics is having second order effects on the microbial world, because these small molecules act as drivers of bacterial evolution. Continued pollution with both xenogenetic elements and the selective agents that fix such elements in populations has potentially adverse consequences for human welfare.
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Affiliation(s)
- Michael R Gillings
- Department of Biological Sciences, Macquarie University Sydney, NSW, Australia
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20
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Wells RM, Jones CM, Xi Z, Speer A, Danilchanka O, Doornbos KS, Sun P, Wu F, Tian C, Niederweis M. Discovery of a siderophore export system essential for virulence of Mycobacterium tuberculosis. PLoS Pathog 2013; 9:e1003120. [PMID: 23431276 PMCID: PMC3561183 DOI: 10.1371/journal.ppat.1003120] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 11/24/2012] [Indexed: 11/18/2022] Open
Abstract
Iron is an essential nutrient for most bacterial pathogens, but is restricted by the host immune system. Mycobacterium tuberculosis (Mtb) utilizes two classes of small molecules, mycobactins and carboxymycobactins, to capture iron from the human host. Here, we show that an Mtb mutant lacking the mmpS4 and mmpS5 genes did not grow under low iron conditions. A cytoplasmic iron reporter indicated that the double mutant experienced iron starvation even under high-iron conditions. Loss of mmpS4 and mmpS5 did not change uptake of carboxymycobactin by Mtb. Thin layer chromatography showed that the ΔmmpS4/S5 mutant was strongly impaired in biosynthesis and secretion of siderophores. Pull-down experiments with purified proteins demonstrated that MmpS4 binds to a periplasmic loop of the associated transporter protein MmpL4. This interaction was corroborated by genetic experiments. While MmpS5 interacted only with MmpL5, MmpS4 interacted with both MmpL4 and MmpL5. These results identified MmpS4/MmpL4 and MmpS5/MmpL5 as siderophore export systems in Mtb and revealed that the MmpL proteins transport small molecules other than lipids. MmpS4 and MmpS5 resemble periplasmic adapter proteins of tripartite efflux pumps of Gram-negative bacteria, however, they are not only required for export but also for efficient siderophore synthesis. Membrane association of MbtG suggests a link between siderophore synthesis and transport. The structure of the soluble domain of MmpS4 (residues 52-140) was solved by NMR and indicates that mycobacterial MmpS proteins constitute a novel class of transport accessory proteins. The bacterial burden of the mmpS4/S5 deletion mutant in mouse lungs was lower by 10,000-fold and none of the infected mice died within 180 days compared to wild-type Mtb. This is the strongest attenuation observed so far for Mtb mutants lacking genes involved in iron utilization. In conclusion, this study identified the first components of novel siderophore export systems which are essential for virulence of Mtb.
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Affiliation(s)
- Ryan M. Wells
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Christopher M. Jones
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Zhaoyong Xi
- School of Chemistry and Material Sciences, University of Science and Technology of China, Hefei, P. R. China
| | - Alexander Speer
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Olga Danilchanka
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Kathryn S. Doornbos
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Peibei Sun
- School of Life Sciences, University of Science and Technology of China, Hefei, P. R. China
| | - Fangming Wu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, P. R. China
| | - Changlin Tian
- School of Life Sciences, University of Science and Technology of China, Hefei, P. R. China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, P. R. China
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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21
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Lee KM, Park Y, Bari W, Yoon MY, Go J, Kim SC, Lee HI, Yoon SS. Activation of cholera toxin production by anaerobic respiration of trimethylamine N-oxide in Vibrio cholerae. J Biol Chem 2012; 287:39742-52. [PMID: 23019319 DOI: 10.1074/jbc.m112.394932] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Vibrio cholerae is a gram-negative bacterium that causes cholera. Although the pathogenesis caused by this deadly pathogen takes place in the intestine, commonly thought to be anaerobic, anaerobiosis-induced virulence regulations are not fully elucidated. Anerobic growth of the V. cholerae strain, N16961, was promoted when trimethylamine N-oxide (TMAO) was used as an alternative electron acceptor. Strikingly, cholera toxin (CT) production was markedly induced during anaerobic TMAO respiration. N16961 mutants unable to metabolize TMAO were incapable of producing CT, suggesting a mechanistic link between anaerobic TMAO respiration and CT production. TMAO reductase is transported to the periplasm via the twin arginine transport (TAT) system. A similar defect in both anaerobic TMAO respiration and CT production was also observed in a N16961 TAT mutant. In contrast, the abilities to grow on TMAO and to produce CT were not affected in a mutant of the general secretion pathway. This suggests that V. cholerae may utilize the TAT system to secrete CT during TMAO respiration. During anaerobic growth with TMAO, N16961 cells exhibit green fluorescence when stained with 2',7'-dichlorofluorescein diacetate, a specific dye for reactive oxygen species (ROS). Furthermore, CT production was decreased in the presence of an ROS scavenger suggesting a positive role of ROS in regulating CT production. When TMAO was co-administered to infant mice infected with N16961, the mice exhibited more severe pathogenic symptoms. Together, our results reveal a novel anaerobic growth condition that stimulates V. cholerae to produce its major virulence factor.
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Affiliation(s)
- Kang-Mu Lee
- Department of Microbiology and Immunology, Brain Korea 21 Project for Medical Sciences, Seoul, 120-752 Korea
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22
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Renier S, Micheau P, Talon R, Hébraud M, Desvaux M. Subcellular localization of extracytoplasmic proteins in monoderm bacteria: rational secretomics-based strategy for genomic and proteomic analyses. PLoS One 2012; 7:e42982. [PMID: 22912771 PMCID: PMC3415414 DOI: 10.1371/journal.pone.0042982] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 07/13/2012] [Indexed: 11/20/2022] Open
Abstract
Genome-scale prediction of subcellular localization (SCL) is not only useful for inferring protein function but also for supporting proteomic data. In line with the secretome concept, a rational and original analytical strategy mimicking the secretion steps that determine ultimate SCL was developed for Gram-positive (monoderm) bacteria. Based on the biology of protein secretion, a flowchart and decision trees were designed considering (i) membrane targeting, (ii) protein secretion systems, (iii) membrane retention, and (iv) cell-wall retention by domains or post-translocational modifications, as well as (v) incorporation to cell-surface supramolecular structures. Using Listeria monocytogenes as a case study, results were compared with known data set from SCL predictors and experimental proteomics. While in good agreement with experimental extracytoplasmic fractions, the secretomics-based method outperforms other genomic analyses, which were simply not intended to be as inclusive. Compared to all other localization predictors, this method does not only supply a static snapshot of protein SCL but also offers the full picture of the secretion process dynamics: (i) the protein routing is detailed, (ii) the number of distinct SCL and protein categories is comprehensive, (iii) the description of protein type and topology is provided, (iv) the SCL is unambiguously differentiated from the protein category, and (v) the multiple SCL and protein category are fully considered. In that sense, the secretomics-based method is much more than a SCL predictor. Besides a major step forward in genomics and proteomics of protein secretion, the secretomics-based method appears as a strategy of choice to generate in silico hypotheses for experimental testing.
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Affiliation(s)
- Sandra Renier
- INRA, UR454 Microbiology, Saint-Genès Champanelle, France
| | - Pierre Micheau
- INRA, UR454 Microbiology, Saint-Genès Champanelle, France
| | - Régine Talon
- INRA, UR454 Microbiology, Saint-Genès Champanelle, France
| | - Michel Hébraud
- INRA, UR454 Microbiology, Saint-Genès Champanelle, France
| | - Mickaël Desvaux
- INRA, UR454 Microbiology, Saint-Genès Champanelle, France
- * E-mail:
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23
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Mechanism of action of the arylomycin antibiotics and effects of signal peptidase I inhibition. Antimicrob Agents Chemother 2012; 56:5054-60. [PMID: 22802255 DOI: 10.1128/aac.00785-12] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clinically approved antibiotics inhibit only a small number of conserved pathways that are essential for bacterial viability, and the physiological effects of inhibiting these pathways have been studied in great detail. Likewise, characterizing the effects of candidate antibiotics that function via novel mechanisms of action is critical for their development, which is of increasing importance due to the ever-growing problem of resistance. The arylomycins are a novel class of natural-product antibiotics that act via the inhibition of type I signal peptidase (SPase), which is an essential enzyme that functions as part of the general secretory pathway and is not the target of any clinically deployed antibiotic. Correspondingly, little is known about the effects of SPase inhibition or how bacteria may respond to mitigate the associated secretion stress. Using genetically sensitized Escherichia coli and Staphylococcus aureus as model organisms, we examine the activity of arylomycin as a function of its concentration, bacterial cell density, target expression levels, and bacterial growth phase. The results reveal that the activity of the arylomycins results from an insufficient flux of proteins through the secretion pathway and the resulting mislocalization of proteins. Interestingly, this has profoundly different effects on E. coli and S. aureus. Finally, we examine the activity of arylomycin in combination with distinct classes of antibiotics and demonstrate that SPase inhibition results in synergistic sensitivity when combined with an aminoglycoside.
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24
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Sevastsyanovich YR, Leyton DL, Wells TJ, Wardius CA, Tveen-Jensen K, Morris FC, Knowles TJ, Cunningham AF, Cole JA, Henderson IR. A generalised module for the selective extracellular accumulation of recombinant proteins. Microb Cell Fact 2012; 11:69. [PMID: 22640772 PMCID: PMC3419692 DOI: 10.1186/1475-2859-11-69] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Accepted: 05/11/2012] [Indexed: 11/10/2022] Open
Abstract
Background It is widely believed that laboratory strains of Escherichia coli, including those used for industrial production of proteins, do not secrete proteins to the extracellular milieu. Results Here, we report the development of a generalised module, based on an E. coli autotransporter secretion system, for the production of extracellular recombinant proteins. We demonstrate that a wide variety of structurally diverse proteins can be secreted as soluble proteins when linked to the autotransporter module. Yields were comparable to those achieved with other bacterial secretion systems. Conclusions The advantage of this module is that it relies on a relatively simple and easily manipulated secretion system, exhibits no apparent limitation to the size of the secreted protein and can deliver proteins to the extracellular environment at levels of purity and yields sufficient for many biotechnological applications.
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Affiliation(s)
- Yanina R Sevastsyanovich
- School of Immunity and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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25
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Tan YX, Romesberg FE. Latent antibiotics and the potential of the arylomycins for broad-spectrum antibacterial activity. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md20043k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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26
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Tame JR. Autotransporter protein secretion. Biomol Concepts 2011; 2:525-36. [DOI: 10.1515/bmc.2011.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 09/16/2011] [Indexed: 11/15/2022] Open
Abstract
AbstractAutotransporter proteins are a large family of virulence factors secreted from Gram-negative bacteria by a unique mechanism. First described in the 1980s, these proteins have a C-terminal region that folds into a β-barrel in the bacterial outer membrane. The so-called passenger domain attached to this barrel projects away from the cell surface and may be liberated from the cell by self-cleavage or surface proteases. Although the majority of passenger domains have a similar β-helical structure, they carry a variety of subdomains, allowing them to carry out widely differing functions related to pathogenesis. Considerable biochemical and structural characterisation of the barrel domain has shown that ‘autotransporters’ in fact require a conserved and essential protein complex in the outer membrane for correct folding. Although the globular domains of this complex projecting into the periplasmic space have also been structurally characterised, the overall secretion pathway of the autotransporters remains highly puzzling. It was presumed for many years that the passenger domain passed through the centre of the barrel domain to reach the cell surface, driven at least in part by folding. This picture is complicated by conflicting data, and there is currently little hard information on the true nature of the secretion intermediates. As well as their medical importance therefore, autotransporters are proving to be an excellent system to study the folding and membrane insertion of outer membrane proteins in general. This review focuses on structural aspects of autotransporters; their many functions in pathogenesis are beyond its scope.
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Affiliation(s)
- Jeremy R.H. Tame
- 1Yokohama City University, Suehiro 1-7-29, Tsurumi, Yokohama 230-0045, Japan
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27
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Le Blastier S, Hamels A, Cabeen M, Schille L, Tilquin F, Dieu M, Raes M, Matroule JY. Phosphate starvation triggers production and secretion of an extracellular lipoprotein in Caulobacter crescentus. PLoS One 2010; 5:e14198. [PMID: 21152032 PMCID: PMC2996285 DOI: 10.1371/journal.pone.0014198] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 11/04/2010] [Indexed: 11/18/2022] Open
Abstract
Life in oligotrophic environments necessitates quick adaptive responses to a sudden lack of nutrients. Secretion of specific degradative enzymes into the extracellular medium is a means to mobilize the required nutrient from nearby sources. The aquatic bacterium Caulobacter crescentus must often face changes in its environment such as phosphate limitation. Evidence reported in this paper indicates that under phosphate starvation, C. crescentus produces a membrane surface-anchored lipoprotein named ElpS subsequently released into the extracellular medium. A complete set of 12 genes encoding a type II secretion system (T2SS) is located adjacent to the elpS locus in the C. crescentus genome. Deletion of this T2SS impairs release of ElpS in the environment, which surprisingly remains present at the cell surface, indicating that the T2SS is not involved in the translocation of ElpS to the outer membrane but rather in its release. Accordingly, treatment with protease inhibitors prevents release of ElpS in the extracellular medium suggesting that ElpS secretion relies on a T2SS-secreted protease. Finally, secretion of ElpS is associated with an increase in alkaline phosphatase activity in culture supernatants, suggesting a role of the secreted protein in inorganic phosphate mobilization. In conlusion, we have shown that upon phosphate starvation, C. crescentus produces an outer membrane bound lipoprotein, ElpS, which is further cleaved and released in the extracellular medium in a T2SS-dependent manner. Our data suggest that ElpS is associated with an alkaline phosphatase activity, thereby allowing the bacterium to gather inorganic phosphates from a poor environment.
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Affiliation(s)
- Sophie Le Blastier
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
| | - Aurore Hamels
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
| | - Matthew Cabeen
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Lionel Schille
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
| | - Françoise Tilquin
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
| | - Marc Dieu
- Unité de Recherche en Biologie Cellulaire, University of Namur, Namur, Belgium
| | - Martine Raes
- Unité de Recherche en Biologie Cellulaire, University of Namur, Namur, Belgium
| | - Jean-Yves Matroule
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
- * E-mail:
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28
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Goudenège D, Avner S, Lucchetti-Miganeh C, Barloy-Hubler F. CoBaltDB: Complete bacterial and archaeal orfeomes subcellular localization database and associated resources. BMC Microbiol 2010; 10:88. [PMID: 20331850 PMCID: PMC2850352 DOI: 10.1186/1471-2180-10-88] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 03/23/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The functions of proteins are strongly related to their localization in cell compartments (for example the cytoplasm or membranes) but the experimental determination of the sub-cellular localization of proteomes is laborious and expensive. A fast and low-cost alternative approach is in silico prediction, based on features of the protein primary sequences. However, biologists are confronted with a very large number of computational tools that use different methods that address various localization features with diverse specificities and sensitivities. As a result, exploiting these computer resources to predict protein localization accurately involves querying all tools and comparing every prediction output; this is a painstaking task. Therefore, we developed a comprehensive database, called CoBaltDB, that gathers all prediction outputs concerning complete prokaryotic proteomes. DESCRIPTION The current version of CoBaltDB integrates the results of 43 localization predictors for 784 complete bacterial and archaeal proteomes (2.548.292 proteins in total). CoBaltDB supplies a simple user-friendly interface for retrieving and exploring relevant information about predicted features (such as signal peptide cleavage sites and transmembrane segments). Data are organized into three work-sets ("specialized tools", "meta-tools" and "additional tools"). The database can be queried using the organism name, a locus tag or a list of locus tags and may be browsed using numerous graphical and text displays. CONCLUSIONS With its new functionalities, CoBaltDB is a novel powerful platform that provides easy access to the results of multiple localization tools and support for predicting prokaryotic protein localizations with higher confidence than previously possible. CoBaltDB is available at http://www.umr6026.univ-rennes1.fr/english/home/research/basic/software/cobalten.
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Affiliation(s)
- David Goudenège
- CNRS UMR 6026, ICM, Equipe B@SIC, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes, France
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Bhavsar AP, Auweter SD, Finlay BB. Proteomics as a probe of microbial pathogenesis and its molecular boundaries. Future Microbiol 2010; 5:253-65. [DOI: 10.2217/fmb.09.114] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Proteomic technology offers an unprecedented systematic approach to investigate the protein complement of any organism. The field of microbial pathogenesis has greatly benefited from other systems approaches, and the application of proteomics to the study of infectious agents is beginning to emerge. Such applications include unambiguously identifying complete virulence factor inventories, studying the response of both host and pathogen to the infection process and elucidating mechanistic actions of virulence factors as they interface with host cells. This review will highlight examples where proteomic studies have contributed to our understanding of pathogenesis in these areas, with an emphasis on pathogens that employ type III and type IV secretion systems. In addition, we will discuss areas where proteomics may help shape further investigation and discovery in this field.
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Affiliation(s)
- Amit P Bhavsar
- The University of British Columbia, Michael Smith Laboratories, 301-2185 East Mall Road, Vancouver, BC, V6T 1Z4, Canada
| | - Sigrid D Auweter
- The University of British Columbia, Michael Smith Laboratories, 301-2185 East Mall Road, Vancouver, BC, V6T 1Z4, Canada
| | - B Brett Finlay
- The University of British Columbia, Michael Smith Laboratories, 301–2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
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Desvaux M, Hébraud M, Talon R, Henderson IR. Outer membrane translocation: numerical protein secretion nomenclature in question in mycobacteria. Trends Microbiol 2009; 17:338-40. [PMID: 19674902 DOI: 10.1016/j.tim.2009.05.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 04/29/2009] [Accepted: 05/12/2009] [Indexed: 11/25/2022]
Affiliation(s)
- Mickaël Desvaux
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France.
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A comparative genomics, network-based approach to understanding virulence in Vibrio cholerae. J Bacteriol 2009; 191:6262-72. [PMID: 19666715 DOI: 10.1128/jb.00475-09] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our views of the genes that drive phenotypes have generally been built up one locus or operon at a time. However, a given phenotype, such as virulence, is a multilocus phenomenon. To gain a more comprehensive view of the genes and interactions underlying a phenotype, we propose an approach that incorporates information from comparative genomics and network biology and illustrate it by examining the virulence phenotype of Vibrio cholerae O1 El Tor N16961. We assessed the associations among the virulence-associated proteins from Vibrio cholerae and all the other proteins from this bacterium using a functional-association network map. In the context of this map, we were able to identify 262 proteins that are functionally linked to the virulence-associated genes more closely than is typical of the proteins in this strain and 240 proteins that are functionally linked to the virulence-associated proteins with a confidence score greater than 0.9. The roles of these genes were investigated using functional information from online data sources, comparative genomics, and the relationships shown by the protein association map. We also incorporated core proteome data from the family Vibrionaceae; 35% of the virulence-associated proteins have orthologs among the 1,822 orthologous groups of proteins in the core proteome, indicating that they may be dual-role virulence genes or encode functions that have value outside the human host. This approach is a valuable tool in searching for novel functional associations and in investigating the relationship between genotype and phenotype.
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Desvaux M, Hébraud M, Talon R, Henderson IR. Secretion and subcellular localizations of bacterial proteins: a semantic awareness issue. Trends Microbiol 2009; 17:139-45. [PMID: 19299134 DOI: 10.1016/j.tim.2009.01.004] [Citation(s) in RCA: 261] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 12/17/2008] [Accepted: 01/16/2009] [Indexed: 12/24/2022]
Abstract
Extracellular proteins are a subject of intense interest because of their essential roles in bacterial lifestyles. However, several terms related to secretion are used confusingly in the literature, and this is a topical issue in genomics and proteomics. Defining a secreted protein as actively translocated via a secretion system, here, we put into perspective that homologous translocation systems can result in radically different subcellular localizations of a secreted protein. We propose using standardized nomenclature for secretion systems from type I to type VIII for Gram-negative bacteria only, whereas the terms 'Sec' (secretion), 'Tat' (twin-arginine translocation), 'FEA' (flagella export apparatus), 'FPE' (fimbrilin-protein exporter), 'holin' (hole forming) and 'Wss' (WXG100 secretion system) should be applied to translocation systems across the cytoplasmic membrane of both Gram-positive and Gram-negative bacteria. Finally, we discuss why the term 'exoproteome' should be favoured over 'secretome' when describing the subset of proteins present in the extracellular milieu.
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Affiliation(s)
- Mickaël Desvaux
- INRA (Institut National de la Recherche Agronomique), UR454 Microbiologie, Centre de Recherche Clermont-Ferrand, F-63122 Saint-Genès Champanelle, France.
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Torto-Alalibo T, Collmer CW, Gwinn-Giglio M. The Plant-Associated Microbe Gene Ontology (PAMGO) Consortium: community development of new Gene Ontology terms describing biological processes involved in microbe-host interactions. BMC Microbiol 2009; 9 Suppl 1:S1. [PMID: 19278549 PMCID: PMC2654661 DOI: 10.1186/1471-2180-9-s1-s1] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
All microbes that form beneficial, neutral, or pathogenic associations with hosts face similar challenges. They must physically adhere to and/or gain entry to host tissues; they must avoid, suppress, or tolerate host defenses; they must acquire nutrients from the host and successfully multiply. Microbes that associate with hosts come from many kingdoms of life and include bacteria, fungi, oomycetes, and nematodes. The increasing numbers of full genome sequences from these diverse microbes provide the opportunity to discover common mechanisms by which the microbes forge and maintain intimate associations with host organisms. However, cross-genome analyses have been hindered by lack of a universal vocabulary for describing biological processes involved in the interplay between microbes and their hosts. The Plant-Associated Microbe Gene Ontology (PAMGO) Consortium has been working for three years as an official interest group of the Gene Ontology (GO) Consortium to develop well-defined GO terms that describe many of the biological processes common to diverse plant- and animal-associated microbes. Creating these terms, over 700 at this time, has required a synthesis of diverse points of view from many research communities. The use of these terms in genome annotation will allow cross-genome searches for genes with common function (without demand for sequence similarity) and also improve the interpretation of data from high-throughput microarray and proteomic analyses. This article, and the more focused mini-reviews that make up this supplement to BMC Microbiology, describe the development and use of these terms.
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Affiliation(s)
- Trudy Torto-Alalibo
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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Lee EY, Choi DS, Kim KP, Gho YS. Proteomics in gram-negative bacterial outer membrane vesicles. MASS SPECTROMETRY REVIEWS 2008; 27:535-555. [PMID: 18421767 DOI: 10.1002/mas.20175] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Gram-negative bacteria constitutively secrete outer membrane vesicles (OMVs) into the extracellular milieu. Recent research in this area has revealed that OMVs may act as intercellular communicasomes in polyspecies communities by enhancing bacterial survival and pathogenesis in hosts. However, the mechanisms of vesicle formation and the pathophysiological roles of OMVs have not been clearly defined. While it is obvious that mass spectrometry-based proteomics offers great opportunities for improving our knowledge of bacterial OMVs, limited proteomic data are available for OMVs. The present review aims to give an overview of the previous biochemical, biological, and proteomic studies in the emerging field of bacterial OMVs, and to give future directions for high-throughput and comparative proteomic studies of OMVs that originate from diverse Gram-negative bacteria under various environmental conditions. This article will hopefully stimulate further efforts to construct a comprehensive proteome database of bacterial OMVs that will help us not only to elucidate the biogenesis and functions of OMVs but also to develop diagnostic tools, vaccines, and antibiotics effective against pathogenic bacteria.
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Affiliation(s)
- Eun-Young Lee
- Department of Life Science and Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
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35
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Evans FF, Egan S, Kjelleberg S. Ecology of type II secretion in marine gammaproteobacteria. Environ Microbiol 2008; 10:1101-7. [DOI: 10.1111/j.1462-2920.2007.01545.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Song H, Sandie R, Wang Y, Andrade-Navarro MA, Niederweis M. Identification of outer membrane proteins of Mycobacterium tuberculosis. Tuberculosis (Edinb) 2008; 88:526-44. [PMID: 18439872 DOI: 10.1016/j.tube.2008.02.004] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 02/08/2008] [Accepted: 02/18/2008] [Indexed: 01/03/2023]
Abstract
The cell wall of mycobacteria includes an unusual outer membrane of extremely low permeability. While Escherichia coli uses more than 60 proteins to functionalize its outer membrane, only two mycobacterial outer membrane proteins (OMPs) are known. The porin MspA of Mycobacterium smegmatis provided the proof of principle that integral mycobacterial OMPs share the beta-barrel structure, the absence of hydrophobic alpha-helices and the presence of a signal peptide with OMPs of gram-negative bacteria. These properties were exploited in a multi-step bioinformatic approach to predict OMPs of M. tuberculosis. A secondary structure analysis was performed for 587 proteins of M. tuberculosis predicted to be exported. Scores were calculated for the beta-strand content and the amphiphilicity of the beta-strands. Reference OMPs of gram-negative bacteria defined threshold values for these parameters that were met by 144 proteins of unknown function of M. tuberculosis. Two of them were verified as OMPs by a novel two-step experimental approach. Rv1698 and Rv1973 were detected only in the total membrane fraction of M. bovis BCG in Western blot experiments, while proteinase K digestion of whole cells showed the surface accessibility of these proteins. These findings established that Rv1698 and Rv1973 are indeed localized in the outer membrane and tripled the number of known OMPs of M. tuberculosis. Significantly, these results provide evidence for the usefulness of the bioinformatic approach to predict mycobacterial OMPs and indicate that M. tuberculosis likely has many OMPs with beta-barrel structure. Our findings pave the way to identify the set of proteins which functionalize the outer membrane of M. tuberculosis.
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Affiliation(s)
- Houhui Song
- Department of Microbiology, University of Alabama at Birmingham, 609 Bevill Biomedical Research Building, 845 19th Street South, Birmingham, AL 35294, USA
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Shiue SJ, Chien IL, Chan NL, Leu WM, Hu NT. Mutation of a key residue in the type II secretion system ATPase uncouples ATP hydrolysis from protein translocation. Mol Microbiol 2007; 65:401-12. [PMID: 17630971 DOI: 10.1111/j.1365-2958.2007.05795.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Membrane-associated ATPase constitutes an essential element common to all secretion machineries in Gram-negative bacteria. How ATP hydrolysis by these ATPases is coupled to secretion process remains unclear. Here we identified R286 as a key residue in the type II secretion system (T2SS) ATPase XpsE of Xanthomonas campestris that plays a pivotal role in coupling ATP hydrolysis to protein translocation. Mutation of R286 to alanine made XpsE hydrolyse ATP at a rate five times that of the wild-type XpsE. Yet the mutant XpsE(R286A) is non-functional in protein secretion via T2SS. Detailed analyses indicated that the mutant XpsE(R286A) lost the ability co-ordinating the N- and C-domain of XpsE. Without significantly influencing XpsE binding affinity with ATP or its oligomerization, R286A mutation however, caused XpsE lose the ability to associate with the cytoplasmic membrane via XpsL(N). As a consequence, ATP hydrolysis by XpsE was uncoupled from protein secretion. Because R286 is highly conserved among members of the secretion NTPase superfamily, we speculate that its equivalent in other homologues may also play a critical energy coupling role for T2SS, type IV pilus assembly and type IV secretion system.
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Affiliation(s)
- Sheng-Jie Shiue
- Institute of Biochemistry, National Chung Hsing University, Taichung, Taiwan
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38
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Planchon S, Chambon C, Desvaux M, Chafsey I, Leroy S, Talon R, Hébraud M. Proteomic Analysis of Cell Envelope fromStaphylococcusxylosusC2a, a Coagulase-Negative Staphylococcus. J Proteome Res 2007; 6:3566-80. [PMID: 17636987 DOI: 10.1021/pr070139+] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Staphylococcus xylosus is a saprophytic bacterium commonly found on skin of mammals but also used for its organoleptic properties in manufacturing of fermented meat products. This bacterium is able to form biofilms and to colonize biotic or abiotic surfaces, processes which are mediated, to a certain extent, by cell-envelope proteins. Thus, the present investigation aimed at evaluating and adapting different existing methods for cell-envelope subproteome analyses of the strain S. xylosus C2a. The protocol selected consisted initially of a lysostaphin treatment producing protoplasts and giving a fraction I enriched in cell wall proteins. A second fraction enriched in membrane proteins was then efficiently recovered by a procedure involving delipidation with a mixture of tributyl phosphate, methanol, and acetone and solubilization with a buffer containing ASB14. Proteins were separated using two-dimensional gel electrophoresis (2-DE) and identified using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). A total of 168 protein spots was identified corresponding to 90 distinct proteins. To categorize and analyze these proteomic data, a rational bioinformatic approach was carried out on proteins identified within cell envelope of S. xylosus C2a. Thirty-four proteins were predicted as membrane-associated with 91% present, as expected, within fraction II enriched in membrane proteins: 24 proteins were predicted as membranal, 3 as lipoproteins, and 7 as components of membrane protein complex. Eighteen out of 25 (72%) proteins predicted as secreted were indeed identified in fraction I enriched in cell wall proteins: 6 proteins were predicted as secreted via Sec translocon, and the remaining 19 proteins were predicted as secreted via unknown secretion system. Eighty-one percent (25/31) of proteins predicted as cytoplasmic were found in fraction II: 8 were clearly predicted as interacting temporarily with membrane components. By coupling conventional 2-DE and bioinformatic analysis, the approach developed allows fractionating, resolving, and analyzing a significant and important set of cell envelope proteins from a coagulase-negative staphylococcus, that is, S. xylosus C2a.
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Affiliation(s)
- Stella Planchon
- INRA Centre de Clermont-Ferrand/Theix, UR454 Microbiologie, Equipe Qualité et Sécurité des Aliments, and Plate-Forme Protéomique, 63122 Saint-Genès Champanelle, France
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39
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Schell MA, Ulrich RL, Ribot WJ, Brueggemann EE, Hines HB, Chen D, Lipscomb L, Kim HS, Mrázek J, Nierman WC, Deshazer D. Type VI secretion is a major virulence determinant in Burkholderia mallei. Mol Microbiol 2007; 64:1466-85. [PMID: 17555434 DOI: 10.1111/j.1365-2958.2007.05734.x] [Citation(s) in RCA: 268] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Burkholderia mallei is a host-adapted pathogen and a category B biothreat agent. Although the B. mallei VirAG two-component regulatory system is required for virulence in hamsters, the virulence genes it regulates are unknown. Here we show with expression profiling that overexpression of virAG resulted in transcriptional activation of approximately 60 genes, including some involved in capsule production, actin-based intracellular motility, and type VI secretion (T6S). The 15 genes encoding the major sugar component of the homopolymeric capsule were up-expressed > 2.5-fold, but capsule was still produced in the absence of virAG. Actin tail formation required virAG as well as bimB, bimC and bimE, three previously uncharacterized genes that were activated four- to 15-fold when VirAG was overproduced. Surprisingly, actin polymerization was found to be dispensable for virulence in hamsters. In contrast, genes encoding a T6S system were up-expressed as much as 30-fold and mutations in this T6S gene cluster resulted in strains that were avirulent in hamsters. SDS-PAGE and mass spectrometry demonstrated that BMAA0742 was secreted by the T6S system when virAG was overexpressed. Purified His-tagged BMAA0742 was recognized by glanders antiserum from a horse, a human and mice, indicating that this Hcp-family protein is produced in vivo during infection.
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Affiliation(s)
- Mark A Schell
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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40
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Evans FF, Raftery MJ, Egan S, Kjelleberg S. Profiling the secretome of the marine bacterium Pseudoalteromonas tunicata using amine-specific isobaric tagging (iTRAQ). J Proteome Res 2007; 6:967-75. [PMID: 17330939 DOI: 10.1021/pr060416x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The eukaryote-associated marine bacterium Pseudoalteromonas tunicata produces a range of target-specific compounds that inhibit different types of marine organisms including invertebrate larvae and algal spores, as well as a broad spectrum of fungi, protozoa, and bacteria. The ability to produce such bioactive compounds is correlated to the expression of a yellow and a purple pigment in P. tunicata. To investigate the regulation and biosynthesis of the pigments and bioactive compounds, the expressed secretome of the pigmented wild-type P. tunicata and a nonpigmented mutant (wmpD-) defective in the type-II secretion pathway were compared. Secreted proteins were digested with trypsin, labeled using amine-specific isobaric tagging reagents (iTRAQ), and identified using two-dimensional SCX and nano C18 RP liquid-chromatography coupled with tandem mass spectrometry (LC/LC-MS/MS). The iTRAQ labeling experiments enabled accurate measurement of the proteins identified in this work. A sequence-base prediction of P. tunicata secretome was also obtained and compared to the expressed proteome to determine the role of the type-II secretion pathway in this bacterium. Our results suggest that this secretion pathway has a role in iron transport and acquisition in P. tunicata.
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Affiliation(s)
- Flavia F Evans
- School of Biotechnology and Biomolecular Sciences, Centre for Marine Biofouling and Bio-Innovation, and Bioanalytical Mass Spectrometry Facility, University of New South Wales, NSW 2052, Australia
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Ruiz T, Lenox C, Radermacher M, Mintz KP. Novel surface structures are associated with the adhesion of Actinobacillus actinomycetemcomitans to collagen. Infect Immun 2006; 74:6163-70. [PMID: 17057091 PMCID: PMC1695496 DOI: 10.1128/iai.00857-06] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Actinobacillus actinomycetemcomitans is a gram-negative, facultative, anaerobic bacterium that colonizes the human oral cavity and the upper respiratory tract. This bacterium is strongly associated with localized aggressive periodontitis and adult periodontitis and is the causative agent for other serious systemic infections. Recently, we have identified a protein, EmaA (extracellular matrix protein adhesin A), that mediates the adhesion of A. actinomycetemcomitans to collagen. The conserved sequence and predicted secondary structure suggest that EmaA is an orthologue of the Yersinia enterocolitica adhesin YadA. Electron microscopy examinations of A. actinomycetemcomitans have identified antenna-like protrusions associated with the surface of the bacterium. These structures are absent on emaA mutant strains and can be restored by transformation of the mutant strain with emaA in trans. The loss of these structures is associated with a decrease in the binding of this bacterium to collagen. The antenna-like structures are composed of a long rod that terminates in an ellipsoidal head region. The analysis of these structures using image processing techniques has provided an initial estimate of the overall dimensions, which suggests that the appendages are oligomeric structures formed by either three or four subunits. Together, the data suggest that emaA is required for the expression of novel appendages on the surface of A. actinomycetemcomitans that mediate the adhesion of the bacterium to collagen.
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Affiliation(s)
- Teresa Ruiz
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05405, USA
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Rahman MS, Ceraul SM, Dreher-Lesnick SM, Beier MS, Azad AF. The lspA gene, encoding the type II signal peptidase of Rickettsia typhi: transcriptional and functional analysis. J Bacteriol 2006; 189:336-41. [PMID: 17098907 PMCID: PMC1797390 DOI: 10.1128/jb.01397-06] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipoprotein processing by the type II signal peptidase (SPase II) is known to be critical for intracellular growth and virulence for many bacteria, but its role in rickettsiae is unknown. Here, we describe the analysis of lspA, encoding a putative SPase II, an essential component of lipoprotein processing in gram-negative bacteria, from Rickettsia typhi. Alignment of deduced amino acid sequences shows the presence of highly conserved residues and domains that are essential for SPase II activity in lipoprotein processing. The transcription of lspA, lgt (encoding prolipoprotein transferase), and lepB (encoding type I signal peptidase), monitored by real-time quantitative reverse transcription-PCR, reveals a differential expression pattern during various stages of rickettsial intracellular growth. The higher transcriptional level of all three genes at the preinfection time point indicates that only live and metabolically active rickettsiae are capable of infection and inducing host cell phagocytosis. lspA and lgt, which are involved in lipoprotein processing, show similar levels of expression. However, lepB, which is involved in nonlipoprotein secretion, shows a higher level of expression, suggesting that LepB is the major signal peptidase for protein secretion and supporting our in silico prediction that out of 89 secretory proteins, only 14 are lipoproteins. Overexpression of R. typhi lspA in Escherichia coli confers increased globomycin resistance, indicating its function as SPase II. In genetic complementation, recombinant lspA from R. typhi significantly restores the growth of temperature-sensitive E. coli Y815 at the nonpermissive temperature, supporting its biological activity as SPase II in prolipoprotein processing.
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Affiliation(s)
- M Sayeedur Rahman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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43
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Desvaux M, Hébraud M. The protein secretion systems in Listeria: inside out bacterial virulence. FEMS Microbiol Rev 2006; 30:774-805. [PMID: 16911044 DOI: 10.1111/j.1574-6976.2006.00035.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Listeria monocytogenes, the etiologic agent of listeriosis, remains a serious public health concern with its frequent occurrence in food coupled with a high mortality rate. The capacity of a bacterium to secrete proteins to or beyond the bacterial cell surface is of crucial importance in the understanding of biofilm formation and bacterial pathogenesis to further develop defensive strategies. Recent findings in protein secretion in Listeria together with the availability of complete genome sequences of several pathogenic L. monocytogenes strains, as well as nonpathogenic Listeria innocua Clip11262, prompted us to summarize the listerial protein secretion systems. Protein secretion would rely essentially on the Sec (Secretion) pathway. The twin-arginine translocation pathway seems encoded in all but one sequenced Listeria. In addition, a functional flagella export apparatus, a fimbrilin-protein exporter, some holins and a WXG100 secretion system are encoded in listerial genomes. This critical review brings new insights into the physiology and virulence of Listeria species.
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Affiliation(s)
- Mickaël Desvaux
- Institut National de la Recherche Agronomique (INRA), Centre de Recherche Clermont-Ferrand-Theix-Lyon, UR 454 Microbiologie, Equipe Qualité et Sécurité des Aliments (QuaSA), Saint-Genès Champanelle, France.
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Abstract
Gram-negative bacteria use the type II secretion system to transport a large number of secreted proteins from the periplasmic space into the extracellular environment. Many of the secreted proteins are major virulence factors in plants and animals. The components of the type II secretion system are located in both the inner and outer membranes where they assemble into a multi-protein, cell-envelope spanning, complex. This review discusses recent progress, particularly newly published structures obtained by X-ray crystallography and electron microscopy that have increased our understanding of how the type II secretion apparatus functions and the role that individual proteins play in this complex system.
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Affiliation(s)
- Tanya L Johnson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620, USA
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Eschenbrenner M, Horn TA, Wagner MA, Mujer CV, Miller-Scandle TL, DelVecchio VG. Comparative Proteome Analysis of Laboratory Grown Brucella abortus 2308 and Brucella melitensis 16M. J Proteome Res 2006; 5:1731-40. [PMID: 16823981 DOI: 10.1021/pr060135p] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Brucella species are pathogenic agents that cause brucellosis, a debilitating zoonotic disease that affects a large variety of domesticated animals and humans. Brucella melitensis and Brucella abortus are considered major health threats because of their highly infectious nature and worldwide occurrence. The availability of the annotated genomes for these two species has allowed a comparative proteomics study of laboratory grown B. melitensis 16M and B. abortus 2308 by two-dimensional (2-D) gel electrophoresis and peptide mass fingerprinting. Computer-assisted analysis of the different 2-D gel images of strains 16M and 2308 revealed significant quantitative and qualitative differences in their protein expression patterns. Proteins involved in membrane transport, particularly the high affinity amino acids binding proteins, and those involved in Sec-dependent secretion systems related to type IV and type V secretion systems, were differentially expressed. Differential expression of these proteins may be responsible for conferring specific host preference in the two strains 2308 and 16M.
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Affiliation(s)
- Michel Eschenbrenner
- Institute of Molecular Biology and Medicine, The University of Scranton, Scranton, Pennsylvania 18510, USA.
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Liu H, Zhang S, Schell MA, Denny TP. Pyramiding unmarked deletions in Ralstonia solanacearum shows that secreted proteins in addition to plant cell-wall-degrading enzymes contribute to virulence. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:1296-305. [PMID: 16478049 DOI: 10.1094/mpmi-18-1296] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Ralstonia solanacearum, like many phytopathogenic bacteria, makes multiple extracellular plant cell-wall-degrading enzymes (CWDE), some of which contribute to its ability to cause wilt disease. CWDE and many other proteins are secreted to the milieu via the highly conserved type II protein secretion system (T2SS). R. solanacearum with a defective T2SS is weakly virulent, but it is not known whether this is due to absence of all the CWDE or the loss of other secreted proteins that contribute to disease. These alternatives were investigated by creating mutants of wild-type strain GMI1000 lacking either the T2SS or up to six CWDE and comparing them for virulence on tomato plants. To create unmarked deletions, genomic regions flanking the target gene were polymerase chain reaction (PCR)-amplified, were fused using splice overlap extension PCR, were cloned into a suicide plasmid harboring the sacB counter-selectable marker, and then, were site-specifically introduced into the genome. Various combinations of five deletions (delta pehA, delta pehB, delta B, PehC, and Pme) was not statistically different from GMI1000, but all the mutants lacking one or both cellulolytic enzymes (Egl or CbhA) wilted plants significantly more slowly than did the wild type. The GMI-6 mutant that lacks all six CWDE was more virulent than the mutant lacking only its two cellulolytic enzymes, and both were significantly more virulent than the T2SS mutant (GMI-D). Very similar results were observed in wounded-petiole inoculation assays, so GMI-6 and GMI-D appear to be less capable of colonizing tomato tissues after invasion. Because the T2SS mutant was much less virulent than the sixfold CWDE mutant, we conclude that other secreted proteins contribute substantially to the ability of R. solanacearum GMI1000 to systemically colonize tomato plants.
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Affiliation(s)
- Huanli Liu
- Department of Plant Pathology, The University of Georgia, Athens, Georgia 30602, USA
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Cianciotto NP. Type II secretion: a protein secretion system for all seasons. Trends Microbiol 2005; 13:581-8. [PMID: 16216510 DOI: 10.1016/j.tim.2005.09.005] [Citation(s) in RCA: 258] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 09/06/2005] [Accepted: 09/22/2005] [Indexed: 01/20/2023]
Abstract
In Gram-negative bacteria, type II secretion (T2S) is one of five protein secretion systems that permit the export of proteins from within the bacterial cell to the extracellular milieu and/or into target host cells. An analysis of numerous sequenced genomes now reveals that T2S genes are common, but by no means universal, in Gram-negative bacteria. Recent functional studies indicate that T2S can promote the virulence of human, animal and plant pathogens, as well as the physiology of various environmental bacteria. Thus, it is an opportune time to highlight the new and different ways in which T2S serves bacterial function.
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Affiliation(s)
- Nicholas P Cianciotto
- Department of Microbiology-Immunology, Northwestern University Medical School, Chicago, IL 60611, USA.
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Desvaux M, Khan A, Scott-Tucker A, Chaudhuri RR, Pallen MJ, Henderson IR. Genomic analysis of the protein secretion systems in Clostridium acetobutylicum ATCC 824. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1745:223-53. [PMID: 15950297 DOI: 10.1016/j.bbamcr.2005.04.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 04/20/2005] [Accepted: 04/20/2005] [Indexed: 12/21/2022]
Abstract
Consistent information about protein secretion in Gram-positive bacteria is essentially restricted to the model organism Bacillus subtilis. Among genome-sequenced clostridia, Clostridium acetobutylicum has been the most extensively studied from a physiological point of view and is the organism for which the largest variety of molecular biology tools have been developed. Following in silico analyses, both secreted proteins and protein secretion systems were identified. The Tat (Twin arginine translocation; TC #2.A.64) pathway and ABC (ATP binding cassette) protein exporters (TC #3.A.1.) could not be identified, but the Sec (secretion) pathway (TC #3.A.5) appears to be used prevalently. Similarly, a flagella export apparatus (FEA; TC #3.A.6.), holins (TC #1.E.), and an ESAT-6/WXG100 (early secreted antigen target of 6 kDa/proteins with a WXG motif of approximately 100 residues) secretion system were identified. Here, we report for the first time the identification of a fimbrilin protein exporter (FPE; TC #3.A.14) and a Tad (tight adherence) export apparatus in C. acetobutylicum. This investigation highlights the potential use of this saprophytic bacterium in biotechnological and biomedical applications as well as a model organism for studying protein secretion in pathogenic Gram-positive bacteria.
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Affiliation(s)
- Mickaël Desvaux
- The Institute for Biomedical Research (IBR), The University of Birmingham-The Medical School, Division of Immunity and Infection, Bacterial Pathogenesis and Genomics Unit, Edgbaston, Birmingham B15 2TT, UK.
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Desvaux M, Khan A, Beatson SA, Scott-Tucker A, Henderson IR. Protein secretion systems in Fusobacterium nucleatum: Genomic identification of Type 4 piliation and complete Type V pathways brings new insight into mechanisms of pathogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1713:92-112. [PMID: 15993836 DOI: 10.1016/j.bbamem.2005.05.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Revised: 04/11/2005] [Accepted: 05/02/2005] [Indexed: 01/01/2023]
Abstract
Recent genomic analyses of the two sequenced strains F. nucleatum subsp. nucleatum ATCC 25586 and F. nucleatum subsp. vincentii ATCC 49256 suggested that the major protein secretion systems were absent. However, such a paucity of protein secretion systems is incongruous with F. nucleatum pathogenesis. Moreover, the presence of one or more such systems has been described for every other Gram-negative organism sequenced to date. In this investigation, the question of protein secretion in F. nucleatum was revisited. In the current study, the absence in F. nucleatum of a twin-arginine translocation system (TC #2.A.64.), a Type III secretion system (TC #3.A.6.), a Type IV secretion system (TC #3.A.7.) and a chaperone/usher pathway (TC #1.B.11.) was confirmed. However, contrary to previous findings, our investigations indicated that a Type I protein secretion system was also absent from F. nucleatum. In contrast, members of the holin family (TC #1.E) and the machinery required for a Type 4 piliation/fimbriation system (TC #3.A.15.2.) were identified using a variety of bioinformatic tools. Furthermore, a complete range of proteins resembling members of the Type V secretion pathway, i.e., the Type Va (autotransporter; TC #1.B.12.), Type Vb (two-partner secretion system; TC #1.B.20.) and Type Vc (YadA-like trimeric autotransporter; TC #1.B.42.), was found. This work provides new insight into the protein secretion and virulence mechanisms of F. nucleatum.
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Affiliation(s)
- Mickaël Desvaux
- The Institute for Biomedical Research (IBR), The University of Birmingham-The Medical School, Division of Immunity and Infection, Bacterial Pathogenesis and Genomics Unit, Edgbaston, Birmingham B15 2TT, UK
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