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Sang S, Song W, Lu L, Ou Q, Guan Y, Tao H, Wang Y, Liu C. The Trimeric Autotransporter Adhesin SadA from Salmonella spp. as a Novel Bacterial Surface Display System. Vaccines (Basel) 2024; 12:399. [PMID: 38675781 PMCID: PMC11054257 DOI: 10.3390/vaccines12040399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024] Open
Abstract
Bacterial surface display platforms have been developed for applications such as vaccine delivery and peptide library screening. The type V secretion system is an attractive anchoring motif for the surface expression of foreign proteins in gram-negative bacteria. SadA belongs to subtype C of the type V secretion system derived from Salmonella spp. and promotes biofilm formation and host cell adherence. The inner membrane lipoprotein SadB is important for SadA translocation. In this study, SadA was used as an anchoring motif to expose heterologous proteins in Salmonella typhimurium using SadB. The ability of SadA to display heterologous proteins on the S. typhimurium surface in the presence of SadB was approximately three-fold higher than that in its absence of SadB. Compared to full-length SadA, truncated SadAs (SadA877 and SadA269) showed similar display capacities when exposing the B-cell epitopes of urease B from Helicobacter pylori (UreB158-172aa and UreB349-363aa). We grafted different protein domains, including mScarlet (red fluorescent protein), the urease B fragment (UreBm) from H. pylori SS1, and/or protective antigen domain 4 from Bacillus anthracis A16R (PAD4), onto SadA877 or SadA1292. Whole-cell dot blotting, immunofluorescence, and flow cytometric analyses confirmed the localization of Flag×3-mScarlet (~30 kDa) and Flag×3-UreBm-mScarlet (~58 kDa) to the S. typhimurium surface using truncated SadA877 or SadA1292 as an anchoring motif. However, Flag×3-UreBm-PAD4-mScarlet (~75 kDa) was displayed on S. typhimurium using SadA1292. The oral administrated pSadBA1292-FUM/StmΔygeAΔmurI and pSadBA877-FUM/StmΔygeAΔmurI could elicit a significant mucosal and humoral immunity response. SadA could thus be used as an anchoring motif for the surface expression of large heterologous proteins as a potential strategy for attenuated bacterial vaccine development.
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Affiliation(s)
- Shuli Sang
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Wenge Song
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Lu Lu
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Qikun Ou
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
- School of Basic Medical Sciences, Guangxi Medical University, 22 Shuangyong Road, Nanning 530021, China
| | - Yiyan Guan
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Haoxia Tao
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Yanchun Wang
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Chunjie Liu
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
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2
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Yoshimoto S, Ishii S, Kawashiri A, Matsushita T, Linke D, Göttig S, Kempf VAJ, Takai M, Hori K. Adhesion preference of the sticky bacterium Acinetobacter sp. Tol 5. Front Bioeng Biotechnol 2024; 12:1342418. [PMID: 38375452 PMCID: PMC10875045 DOI: 10.3389/fbioe.2024.1342418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/22/2024] [Indexed: 02/21/2024] Open
Abstract
Gram-negative bacterium Acinetobacter sp. Tol 5 exhibits high adhesiveness to various surfaces of general materials, from hydrophobic plastics to hydrophilic glass and metals, via AtaA, an Acinetobacter trimeric autotransporter adhesin Although the adhesion of Tol 5 is nonspecific, Tol 5 cells may have prefer materials for adhesion. Here, we examined the adhesion of Tol 5 and other bacteria expressing different TAAs to various materials, including antiadhesive surfaces. The results highlighted the stickiness of Tol 5 through the action of AtaA, which enabled Tol 5 cells to adhere even to antiadhesive materials, including polytetrafluoroethylene with a low surface free energy, a hydrophilic polymer brush with steric hindrance, and mica with an ultrasmooth surface. Single-cell force spectroscopy as an atomic force microscopy technique revealed the strong cell adhesion force of Tol 5 to these antiadhesive materials. Nevertheless, Tol 5 cells showed a weak adhesion force toward a zwitterionic 2-methacryloyloxyethyl-phosphorylcholine (MPC) polymer-coated surface. Dynamic flow chamber experiments revealed that Tol 5 cells, once attached to the MPC polymer-coated surface, were exfoliated by weak shear stress. The underlying adhesive mechanism was presumed to involve exchangeable, weakly bound water molecules. Our results will contribute to the understanding and control of cell adhesion of Tol 5 for immobilized bioprocess applications and other TAA-expressing pathogenic bacteria of medical importance.
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Affiliation(s)
- Shogo Yoshimoto
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Aichi, Japan
| | - Satoshi Ishii
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Aichi, Japan
| | - Ayane Kawashiri
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Aichi, Japan
| | - Taishi Matsushita
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Stephan Göttig
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Volkhard A. J. Kempf
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Madoka Takai
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Katsutoshi Hori
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Aichi, Japan
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3
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Hatlem D, Christensen M, Broeker NK, Kristiansen PE, Lund R, Barbirz S, Linke D. A trimeric coiled-coil motif binds bacterial lipopolysaccharides with picomolar affinity. Front Cell Infect Microbiol 2023; 13:1125482. [PMID: 36875521 PMCID: PMC9978483 DOI: 10.3389/fcimb.2023.1125482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 01/30/2023] [Indexed: 02/18/2023] Open
Abstract
α-helical coiled-coils are ubiquitous protein structures in all living organisms. For decades, modified coiled-coils sequences have been used in biotechnology, vaccine development, and biochemical research to induce protein oligomerization, and form self-assembled protein scaffolds. A prominent model for the versatility of coiled-coil sequences is a peptide derived from the yeast transcription factor, GCN4. In this work, we show that its trimeric variant, GCN4-pII, binds bacterial lipopolysaccharides (LPS) from different bacterial species with picomolar affinity. LPS molecules are highly immunogenic, toxic glycolipids that comprise the outer leaflet of the outer membrane of Gram-negative bacteria. Using scattering techniques and electron microscopy, we show how GCN4-pII breaks down LPS micelles in solution. Our findings suggest that the GCN4-pII peptide and derivatives thereof could be used for novel LPS detection and removal solutions with high relevance to the production and quality control of biopharmaceuticals and other biomedical products, where even minuscule amounts of residual LPS can be lethal.
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Affiliation(s)
- Daniel Hatlem
- Institutt for Biovitenskap, Universitetet i Oslo, Oslo, Norway
| | | | - Nina K. Broeker
- Department Humanmedizin, HMU Health and Medical University, Potsdam, Germany
| | | | - Reidar Lund
- Kjemisk Institutt, Universitetet i Oslo, Oslo, Norway
| | - Stefanie Barbirz
- Department Humanmedizin, HMU Health and Medical University, Potsdam, Germany
| | - Dirk Linke
- Institutt for Biovitenskap, Universitetet i Oslo, Oslo, Norway
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4
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Thibau A, Vaca DJ, Bagowski M, Hipp K, Bender D, Ballhorn W, Linke D, Kempf VAJ. Adhesion of Bartonella henselae to Fibronectin Is Mediated via Repetitive Motifs Present in the Stalk of Bartonella Adhesin A. Microbiol Spectr 2022; 10:e0211722. [PMID: 36165788 PMCID: PMC9602544 DOI: 10.1128/spectrum.02117-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/06/2022] [Indexed: 12/31/2022] Open
Abstract
Adhesion to host cells is the first and most crucial step in infections with pathogenic Gram-negative bacteria and is often mediated by trimeric autotransporter adhesins (TAAs). Bartonella henselae targets the extracellular matrix glycoprotein fibronectin (Fn) via the Bartonella adhesin A (BadA) attaching the bacteria to the host cell. The TAA BadA is characterized by a highly repetitive passenger domain consisting of 30 neck/stalk domains with various degrees of similarity. To elucidate the motif sequences mediating Fn binding, we generated 10 modified BadA constructs and verified their expression via Western blotting, confocal laser scanning, and electron microscopy. We analyzed their ability to bind human plasma Fn using quantitative whole-cell enzyme-linked immunosorbent assays (ELISAs) and fluorescence microscopy. Polyclonal antibodies targeting a 15-mer amino acid motif sequence proved to reduce Fn binding. We suggest that BadA adheres to Fn in a cumulative effort with quick saturation primarily via unpaired β-strands appearing in motifs repeatedly present throughout the neck/stalk region. In addition, we demonstrated that the length of truncated BadA constructs correlates with the immunoreactivity of human patient sera. The identification of BadA-Fn binding regions will support the development of new "antiadhesive" compounds inhibiting the initial adherence of B. henselae and other TAA-expressing pathogens to host cells. IMPORTANCE Trimeric autotransporter adhesins (TAAs) are important virulence factors and are widely present in various pathogenic Gram-negative bacteria. TAA-expressing bacteria cause a wide spectrum of human diseases, such as cat scratch disease (Bartonella henselae), enterocolitis (Yersinia enterocolitica), meningitis (Neisseria meningitis), and bloodstream infections (multidrug-resistant Acinetobacter baumannii). TAA-targeted antiadhesive strategies (against, e.g., Bartonella adhesin A [BadA], Yersinia adhesin A [YadA], Neisseria adhesin A [NadA], and Acinetobacter trimeric autotransporter [Ata]) might represent a universal strategy to counteract such bacterial infections. BadA is one of the best characterized TAAs, and because of its high number of (sub)domains, it serves as an attractive adhesin to study the domain-function relationship of TAAs in the infection process. The identification of common binding motifs between TAAs (here, BadA) and their major binding partner (here, fibronectin) provides a basis toward the design of novel "antiadhesive" compounds preventing the initial adherence of Gram-negative bacteria in infections.
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Affiliation(s)
- Arno Thibau
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Diana J. Vaca
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Marlene Bagowski
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Katharina Hipp
- Electron Microscopy Facility, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Daniela Bender
- Federal Institute for Vaccines and Biomedicines, Department of Virology, Paul-Ehrlich-Institut, Langen, Germany
| | - Wibke Ballhorn
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Dirk Linke
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Volkhard A. J. Kempf
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
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5
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Feitosa-Junior OR, Souza APS, Zaini PA, Baccari C, Ionescu M, Pierry PM, Uceda-Campos G, Labroussaa F, Almeida RPP, Lindow SE, da Silva AM. The XadA Trimeric Autotransporter Adhesins in Xylella fastidiosa Differentially Contribute to Cell Aggregation, Biofilm Formation, Insect Transmission and Virulence to Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:857-866. [PMID: 35704683 DOI: 10.1094/mpmi-05-22-0108-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Surface adhesion strategies are widely employed by bacterial pathogens during establishment and systemic spread in their host. A variety of cell-surface appendages such as pili, fimbriae, and afimbrial adhesins are involved in these processes. The phytopathogen Xylella fastidiosa employs several of these structures for efficient colonization of its insect and plant hosts. Among the adhesins encoded in the X. fastidiosa genome, three afimbrial adhesins, XadA1, Hsf/XadA2, and XadA3, are predicted to be trimeric autotransporters with a C-terminal YadA-anchor membrane domain. We analyzed the individual contributions of XadA1, XadA2, and XadA3 to various cellular behaviors both in vitro and in vivo. Using isogenic X. fastidiosa mutants, we found that cell-cell aggregation and biofilm formation were severely impaired in the absence of XadA3. No significant reduction of cell-surface attachment was found with any mutant under flow conditions. Acquisition by insect vectors and transmission to grapevines were reduced in the XadA3 deletion mutant. While the XadA3 mutant was hypervirulent in grapevines, XadA1 or XadA2 deletion mutants conferred lower disease severity than the wild-type strain. This insight of the importance of these adhesive proteins and their individual contributions to different aspects of X. fastidiosa biology should guide new approaches to reduce pathogen transmission and disease development. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Oseias R Feitosa-Junior
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Ana Paula S Souza
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Paulo A Zaini
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Department of Plant Sciences, University of California, Davis, CA, U.S.A
| | - Clelia Baccari
- Department of Plant and Microbial Biology, University of California, Berkeley, U.S.A
| | - Michael Ionescu
- Department of Plant and Microbial Biology, University of California, Berkeley, U.S.A
| | - Paulo M Pierry
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Guillermo Uceda-Campos
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Fabien Labroussaa
- Department of Environmental Science, Policy and Management, University of California, Berkeley, U.S.A
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Rodrigo P P Almeida
- Department of Environmental Science, Policy and Management, University of California, Berkeley, U.S.A
| | - Steven E Lindow
- Department of Plant and Microbial Biology, University of California, Berkeley, U.S.A
| | - Aline M da Silva
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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Kiessling AR, Harris SA, Weimer KM, Wells G, Goldman A. The C-terminal head domain of Burkholderia pseudomallei BpaC has a striking hydrophilic core with an extensive solvent network. Mol Microbiol 2022; 118:77-91. [PMID: 35703459 PMCID: PMC9543794 DOI: 10.1111/mmi.14953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 11/27/2022]
Abstract
Gram‐negative pathogens like Burkholderia pseudomallei use trimeric autotransporter adhesins such as BpaC as key molecules in their pathogenicity. Our 1.4 Å crystal structure of the membrane‐proximal part of the BpaC head domain shows that the domain is exclusively made of left‐handed parallel β‐roll repeats. This, the largest such structure solved, has two unique features. First, the core, rather than being composed of the canonical hydrophobic Ile and Val, is made up primarily of the hydrophilic Thr and Asn, with two different solvent channels. Second, comparing BpaC to all other left‐handed parallel β‐roll structures showed that the position of the head domain in the protein correlates with the number and type of charged residues. In BpaC, only negatively charged residues face the solvent—in stark contrast to the primarily positive surface charge of the left‐handed parallel β‐roll “type” protein, YadA. We propose extending the definitions of these head domains to include the BpaC‐like head domain as a separate subtype, based on its unusual sequence, position, and charge. We speculate that the function of left‐handed parallel β‐roll structures may differ depending on their position in the structure.
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Affiliation(s)
- Andreas R Kiessling
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Sarah A Harris
- Astbury Centre for Structural Molecular Biology, School of Physics and Astronomy, University of Leeds, Leeds, UK
| | - Kathleen M Weimer
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, UK.,IGBMC, School of Life and Health Sciences, University of Strasbourg, Strasbourg, France
| | - Geoffrey Wells
- UCL School of Pharmacy, University College London, London, UK
| | - Adrian Goldman
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, UK.,MIBS, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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7
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Rooke JL, Icke C, Wells TJ, Rossiter AE, Browning DF, Morris FC, Leo JC, Schütz MS, Autenrieth IB, Cunningham AF, Linke D, Henderson IR. BamA and BamD Are Essential for the Secretion of Trimeric Autotransporter Adhesins. Front Microbiol 2021; 12:628879. [PMID: 33708185 PMCID: PMC7940764 DOI: 10.3389/fmicb.2021.628879] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/26/2021] [Indexed: 12/14/2022] Open
Abstract
The BAM complex in Escherichia coli is composed of five proteins, BamA-E. BamA and BamD are essential for cell viability and are required for the assembly of β-barrel outer membrane proteins. Consequently, BamA and BamD are indispensable for secretion via the classical autotransporter pathway (Type 5a secretion). In contrast, BamB, BamC, and BamE are not required for the biogenesis of classical autotransporters. Recently, we demonstrated that TamA, a homologue of BamA, and its partner protein TamB, were required for efficient secretion of proteins via the classical autotransporter pathway. The trimeric autotransporters are a subset of the Type 5-secreted proteins. Unlike the classical autotransporters, they are composed of three identical polypeptide chains which must be assembled together to allow secretion of their cognate passenger domains. In contrast to the classical autotransporters, the role of the Bam and Tam complex components in the biogenesis of the trimeric autotransporters has not been investigated fully. Here, using the Salmonella enterica trimeric autotransporter SadA and the structurally similar YadA protein of Yersinia spp., we identify the importance of BamA and BamD in the biogenesis of the trimeric autotransporters and reveal that BamB, BamC, BamE, TamA and TamB are not required for secretion of functional passenger domain on the cell surface. Importance The secretion of trimeric autotransporters (TAA's) has yet to be fully understood. Here we show that efficient secretion of TAAs requires the BamA and D proteins, but does not require BamB, C or E. In contrast to classical autotransporter secretion, neither trimeric autotransporter tested required TamA or B proteins to be functionally secreted.
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Affiliation(s)
- Jessica L Rooke
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Christopher Icke
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Timothy J Wells
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.,The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Amanda E Rossiter
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Douglas F Browning
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Faye C Morris
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Jack C Leo
- Department of Biosciences, Nottingham Trent University, Nottingham, United Kingdom.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - Monika S Schütz
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Ingo B Autenrieth
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Adam F Cunningham
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Ian R Henderson
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
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8
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Rahbar MR, Zarei M, Jahangiri A, Khalili S, Nezafat N, Negahdaripour M, Fattahian Y, Savardashtaki A, Ghasemi Y. Non-adaptive Evolution of Trimeric Autotransporters in Brucellaceae. Front Microbiol 2020; 11:560667. [PMID: 33281759 PMCID: PMC7688925 DOI: 10.3389/fmicb.2020.560667] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 10/05/2020] [Indexed: 12/14/2022] Open
Abstract
Brucella species are Gram-negative, facultative intracellular pathogens. They are the main cause of brucellosis, which has led to a global health burden. Adherence of the pathogen to the host cells is the first step in the infection process. The bacteria can adhere to various biotic and abiotic surfaces using their outer membrane proteins. Trimeric autotransporter adhesins (TAAs) are modular homotrimers of various length and domain complexity. They are a diverse, and widespread gene family constituting the type Vc secretion pathway. These adhesins have been established as virulence factors in Brucellaceae. To date, no comprehensive and exhaustive study has been performed on the trimeric autotransporter family in the genus. In the present study, various bioinformatics tools were used to provide a novel evolutionary insight into the sequence and structure of this protein family in Brucellaceae. To this end, a dataset of all trimeric autotransporters from the Brucella genomes was built. Analyses included but were not limited to sequence alignment, phylogenetic tree constructions, codon-based test for selection, clustering of the sequences, and structure (primary to quaternary) predictions. Batch analyzes of the dataset suggested the existence of a few structural domains within the whole population. BatA from the B. abortus 2308 genome was selected as a reference to describe the features of these structural domains. Furthermore, we examined the structural basis for the observed rigidity and resiliency of the protein structure through a molecular dynamics evaluation, which led us to deduce that the random drift results in the non-adaptive evolution of the trimeric autotransporter genes in the Brucella genus. Notably, the modifications have occurred across the genus without interference of gene transmission.
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Affiliation(s)
- Mohammad Reza Rahbar
- Pharmaceutical Sciences Research Center, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mahboubeh Zarei
- Pharmaceutical Sciences Research Center, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Abolfazl Jahangiri
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Saeed Khalili
- Department of Biology Sciences, Shahid Rajaee Teacher Training University, Tehran, Iran
| | - Navid Nezafat
- Pharmaceutical Sciences Research Center, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Manica Negahdaripour
- Pharmaceutical Sciences Research Center, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Yaser Fattahian
- Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran
| | - Amir Savardashtaki
- Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Younes Ghasemi
- Pharmaceutical Sciences Research Center, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
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9
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Khalil HS, Øgaard J, Leo JC. Coaggregation properties of trimeric autotransporter adhesins. Microbiologyopen 2020; 9:e1109. [PMID: 32864901 PMCID: PMC7568254 DOI: 10.1002/mbo3.1109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/24/2020] [Accepted: 07/30/2020] [Indexed: 12/19/2022] Open
Abstract
Trimeric autotransporter adhesins (TAAs) comprise a group of virulence‐related proteins in Gram‐negative bacteria. Members of this family bind to extracellular matrix components such as collagen and fibronectin, but also they exhibit several other functions, such as conferring serum resistance and autoaggregation. Autoaggregation promoted by TAAs is homotypic and mediated by the sticky, globular head domains of these lollipop‐like molecules. However, whether TAAs mediate heterotypic interactions (i.e., coaggregation) has not been studied. To address this question, we investigated the coaggregation of two model TAA groups: YadA from the enteropathogenic Yersiniae and the immunoglobulin‐binding Eib proteins from Escherichia coli. To study TAA coaggregation, we coexpressed a fluorescent label together with a particular TAA and followed the aggregative interactions using fluorescence microscopy and quantified the interactions using a novel script implemented in Fiji. Our results show that there is coaggregation between some populations expressing different TAAs, which can be explained by relatively high sequence similarity between the interacting TAAs. Generally, the level of coaggregation correlated with the sequence similarity. However, some TAAs did not interact despite high sequence similarity, showing exclusion of bacteria producing a noncompatible TAA. These data demonstrate that TAAs can mediate bacterial coaggregation, but in some cases prevent coaggregation of bacteria with disparate TAAs. Our results have implications for the ecology of TAA‐producing bacteria, where coaggregation may promote co‐operation whereas exclusion might be an indication of competition.
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Affiliation(s)
- Hawzeen S Khalil
- Section for Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Jonas Øgaard
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Jack C Leo
- Section for Evolution and Genetics, Department of Biosciences, University of Oslo, Oslo, Norway.,Antimicrobial Resistance, Omics and Microbiota Group, Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham, UK
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10
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Thibau A, Dichter AA, Vaca DJ, Linke D, Goldman A, Kempf VAJ. Immunogenicity of trimeric autotransporter adhesins and their potential as vaccine targets. Med Microbiol Immunol 2020; 209:243-263. [PMID: 31788746 PMCID: PMC7247748 DOI: 10.1007/s00430-019-00649-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/19/2019] [Indexed: 12/15/2022]
Abstract
The current problem of increasing antibiotic resistance and the resurgence of numerous infections indicate the need for novel vaccination strategies more than ever. In vaccine development, the search for and the selection of adequate vaccine antigens is the first important step. In recent years, bacterial outer membrane proteins have become of major interest, as they are the main proteins interacting with the extracellular environment. Trimeric autotransporter adhesins (TAAs) are important virulence factors in many Gram-negative bacteria, are localised on the bacterial surface, and mediate the first adherence to host cells in the course of infection. One example is the Neisseria adhesin A (NadA), which is currently used as a subunit in a licensed vaccine against Neisseria meningitidis. Other TAAs that seem promising vaccine candidates are the Acinetobacter trimeric autotransporter (Ata), the Haemophilus influenzae adhesin (Hia), and TAAs of the genus Bartonella. Here, we review the suitability of various TAAs as vaccine candidates.
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Affiliation(s)
- Arno Thibau
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe-University, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Alexander A. Dichter
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe-University, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Diana J. Vaca
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe-University, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Dirk Linke
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Adrian Goldman
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, UK
- Molecular and Integrative Biosciences Program, University of Helsinki, Helsinki, Finland
| | - Volkhard A. J. Kempf
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe-University, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
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11
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Kiessling AR, Malik A, Goldman A. Recent advances in the understanding of trimeric autotransporter adhesins. Med Microbiol Immunol 2020; 209:233-242. [PMID: 31865405 PMCID: PMC7247746 DOI: 10.1007/s00430-019-00652-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 11/30/2019] [Indexed: 01/01/2023]
Abstract
Adhesion is the initial step in the infection process of gram-negative bacteria. It is usually followed by the formation of biofilms that serve as a hub for further spread of the infection. Type V secretion systems engage in this process by binding to components of the extracellular matrix, which is the first step in the infection process. At the same time they provide protection from the immune system by either binding components of the innate immune system or by establishing a physical layer against aggressors. Trimeric autotransporter adhesins (TAAs) are of particular interest in this family of proteins as they possess a unique structural composition which arises from constraints during translocation. The sequence of individual domains can vary dramatically while the overall structure can be very similar to one another. This patchwork approach allows researchers to draw conclusions of the underlying function of a specific domain in a structure-based approach which underscores the importance of solving structures of yet uncharacterized TAAs and their individual domains to estimate the full extent of functions of the protein a priori. Here, we describe recent advances in understanding the translocation process of TAAs and give an overview of structural motifs that are unique to this class of proteins. The role of BpaC in the infection process of Burkholderia pseudomallei is highlighted as an exceptional example of a TAA being at the centre of infection initiation.
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Affiliation(s)
- Andreas R. Kiessling
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds, LS2 9JT England, UK
| | - Anchal Malik
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds, LS2 9JT England, UK
| | - Adrian Goldman
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds, LS2 9JT England, UK
- Faculty of Biological and Environmental Sciences, University of Helsinki, FIN-0014 Helsinki, Finland
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12
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Native display of a huge homotrimeric protein fiber on the cell surface after precise domain deletion. J Biosci Bioeng 2019; 129:412-417. [PMID: 31653547 DOI: 10.1016/j.jbiosc.2019.09.022] [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: 08/21/2019] [Revised: 09/28/2019] [Accepted: 09/30/2019] [Indexed: 11/21/2022]
Abstract
AtaA, a trimeric autotransporter adhesin from Acinetobacter sp. Tol 5, exhibits nonspecific, high adhesiveness to abiotic surfaces. For identification of the functional domains of AtaA, precise design of domain-deletion mutants is necessary so as not to cause undesirable structural distortion. Here, we designed and constructed three types of AtaA mutants from which the same domain, FGG1, was deleted. The first mutant was designed to preserve the periodicity of hydrophobic residues in the coiled-coil segments sandwiching the deleted region. After the deletion, the protein was properly displayed on the cell surface and had the same adhesive function as the wild type. Transmission electron microscopy (TEM) imaging and circular dichroism (CD) spectroscopy showed that its isolated passenger domain had the same fiber structure as in the AtaA wild type. In contrast, a mutant designed to disturb the coiled-coil periodicity at the deletion site failed to reach the cell surface. Although secretion occurred for the mutant designed with a flexible connector between the coiled coils, the cells exhibited a decrease in adhesiveness. Furthermore, TEM imaging of the mutant fibers showed bending at the fiber tip and changes in their CD spectrum indicated a decrease in secondary structure content. Thus, we succeeded to natively display the huge homotrimeric fiber structure of AtaA on the cell surface after precise deletion of a domain, maintaining the proper folding state and adhesive function by preserving its coiled-coil periodicity. This strategy enables us to construct various domain-deletion mutants of AtaA without structural distortion for complete functional mapping.
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13
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Sequential Translocation of Polypeptides across the Bacterial Outer Membrane through the Trimeric Autotransporter Pathway. mBio 2019; 10:mBio.01973-19. [PMID: 31641085 PMCID: PMC6805991 DOI: 10.1128/mbio.01973-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Trimeric autotransporter adhesins (TAAs) are a family of bacterial outer membrane (OM) proteins that are comprised of three identical subunits. Each subunit contains an N-terminal extracellular ("passenger") domain and a short C-terminal segment that contributes four β strands to a single 12-stranded β barrel. The mechanism by which the passenger domains are translocated across the OM and the energetics of the translocation reaction are poorly understood. To address these issues, we examined the secretion of modified versions of the passenger domain of UpaG, a TAA produced by Escherichia coli CFT073. Using the SpyTag-SpyCatcher system to probe passenger domain localization, we found that both intrinsically disordered polypeptides fused to the UpaG passenger domain and artificially disulfide-bonded polypeptides were secreted effectively but relatively slowly. Surprisingly, we also found that in some cases, the three nonnative passenger domain segments associated with a single trimer were secreted sequentially. Photo-cross-linking experiments indicated that incompletely assembled UpaG derivatives remained bound to the barrel assembly machinery (Bam) complex until all three passenger domains were fully secreted. Taken together, our results strongly suggest that the secretion of polypeptides through the TAA pathway is coordinated with the assembly of the β barrel domain and that the folding of passenger domains in the extracellular space maximizes the rate of secretion. Furthermore, our work provides evidence for an unprecedented sequential mode of protein translocation, at least under specific experimental conditions.IMPORTANCE Trimeric autotransporter adhesins (TAAs) are specialized bacterial outer membrane proteins consisting of three identical subunits. TAAs contain large extracellular domains that trimerize and promote virulence, but the mechanism by which they are secreted is poorly understood. We found that the extracellular domains of a native TAA were secreted rapidly but that disordered and artificially folded polypeptides fused to native passenger domains were secreted in a slow, sequential fashion. Our results strongly suggest that the efficient secretion of native extracellular domains is driven by their trimerization following export but that alternative energy sources can be harnessed to secrete nonnative polypeptides. Furthermore, we obtained evidence that TAA extracellular domains are secreted before the assembly of the linked membrane spanning domain is completed.
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14
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Mikula KM, Kolodziejczyk R, Goldman A. Structure of the UspA1 protein fragment from Moraxella catarrhalis responsible for C3d binding. J Struct Biol 2019; 208:77-85. [PMID: 31400508 PMCID: PMC6839023 DOI: 10.1016/j.jsb.2019.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/03/2019] [Accepted: 08/05/2019] [Indexed: 01/26/2023]
Abstract
UspA1299–452 is a left-handed coiled-coil structure that follows TAA rules. Structure of UspA1299–452 contains part of the long neck domain and of the stalk. UspA1-C3d binding does not saturate at C3d physiological concentrations. The binding constant as measured by thermophoresis is at least 140 μM. Full-length proteins or other factors are important for UspA1-C3d interactions.
The gram-negative bacterium Moraxella catarrhalis infects humans exclusively, causing various respiratory tract diseases, including acute otitis media in children, septicaemia or meningitis in adults, and pneumonia in the elderly. To do so, M. catarrhalis expresses virulence factors facilitating its entry and survival in the host. Among them are the ubiquitous surface proteins (Usps): A1, A2, and A2H, which all belong to the trimeric autotransporter adhesin family. They bind extracellular matrix molecules and inhibit the classical and alternative pathways of the complement cascade by recruiting complement regulators C3d and C4b binding protein. Here, we report the 2.5 Å resolution X-ray structure of UspA1299–452, which previous work had suggested contained the canonical C3d binding site found in both UspA1 and UspA2. We show that this fragment of the passenger domain contains part of the long neck domain (residues 299–336) and a fragment of the stalk (residues 337–452). The coiled-coil stalk is left-handed, with 7 polar residues from each chain facing the core and coordinating chloride ions or water molecules. Despite the previous reports of tight binding in serum-based assays, we were not able to demonstrate binding between C3d and UspA1299–452 using ELISA or biolayer interferometry, and the two proteins run separately on size-exclusion chromatography. Microscale thermophoresis suggested that the dissociation constant was 140.5 ± 8.4 μM. We therefore suggest that full-length proteins or other additional factors are important in UspA1-C3d interactions. Other molecules on the bacterial surface or present in serum may enhance binding of those two molecules.
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Affiliation(s)
- Kornelia M Mikula
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Robert Kolodziejczyk
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Adrian Goldman
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, UK.
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15
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Interactions between the Trimeric Autotransporter Adhesin EmaA and Collagen Revealed by Three-Dimensional Electron Tomography. J Bacteriol 2019; 201:JB.00297-19. [PMID: 31160398 DOI: 10.1128/jb.00297-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 05/24/2019] [Indexed: 11/20/2022] Open
Abstract
Bacterial adhesion to host tissues is considered the first and critical step of microbial infection. The extracellular matrix protein adhesin A (EmaA) is a collagen-binding adhesin of the periodontal pathogen Aggregatibacter actinomycetemcomitans Three 202-kDa EmaA monomers form antenna-like structures on the bacterial surface with the functional domain located at the apical end. The structure of the 30-nm functional domain has been determined by three-dimensional (3D) electron tomography and subvolume averaging. The region exhibits a complex architecture composed of three subdomains (SI to SIII) and a linker between subdomains SII and SIII. However, the molecular interaction between the adhesin receptor complexes has yet to be revealed. This study provides the first detailed 3D structure of reconstituted EmaA/collagen complexes obtained using 3D electron tomography and image processing techniques. The observed interactions of EmaA with collagen were not to whole, intact fibrils, but rather to individual collagen triple helices dissociated from the fibrils. The majority of the contacts with the EmaA functional domain encompassed subdomains SII and SIII and in some cases the tip of the apical domain, involving SI. These data suggest a multipronged mechanism for the interaction of Gram-negative bacteria with collagen.IMPORTANCE Bacterial adhesion is a crucial step for bacterial colonization and infection. In recent years, the number of antibiotic-resistant strains has dramatically increased; therefore, there is a need to search for novel antimicrobial agents. Thus, great efforts are being devoted to develop a clear understanding of the bacterial adhesion mechanism for preventing infections. In host/pathogen interactions, once repulsive forces are overcome, adhesins recognize and tightly bind to specific receptors on the host cell or tissue components. Here, we present the first 3D structure of the interaction between the collagen-binding adhesin EmaA and collagen, which is critical for the development of endocarditis in humans.
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16
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Structural diversity of coiled coils in protein fibers of the bacterial cell envelope. Int J Med Microbiol 2019; 309:351-358. [PMID: 31182277 DOI: 10.1016/j.ijmm.2019.05.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/14/2019] [Accepted: 05/31/2019] [Indexed: 02/06/2023] Open
Abstract
The cell envelope of bacteria shows great diversity in architecture and composition, to a large extent due to its proteome. Proteins localized to the cell envelope, whether integrally embedded in the membrane, membrane-anchored, or peripherally associated as part of a macromolecular complex, often form elongated fibers, in which coiled coils represent a prominent structural element. These coiled-coil segments show a surprising degree of structural variability, despite being shaped by a small number of simple biophysical rules, foremost being their geometry of interaction referred to as 'knobs-into-holes'. Here we will review this diversity, particularly as it has emerged over the last decade.
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17
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Paxman JJ, Lo AW, Sullivan MJ, Panjikar S, Kuiper M, Whitten AE, Wang G, Luan CH, Moriel DG, Tan L, Peters KM, Phan MD, Gee CL, Ulett GC, Schembri MA, Heras B. Unique structural features of a bacterial autotransporter adhesin suggest mechanisms for interaction with host macromolecules. Nat Commun 2019; 10:1967. [PMID: 31036849 PMCID: PMC6488583 DOI: 10.1038/s41467-019-09814-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 03/28/2019] [Indexed: 12/31/2022] Open
Abstract
Autotransporters are the largest family of outer membrane and secreted proteins in Gram-negative bacteria. Most autotransporters are localised to the bacterial surface where they promote colonisation of host epithelial surfaces. Here we present the crystal structure of UpaB, an autotransporter that is known to contribute to uropathogenic E. coli (UPEC) colonisation of the urinary tract. We provide evidence that UpaB can interact with glycosaminoglycans and host fibronectin. Unique modifications to its core β-helical structure create a groove on one side of the protein for interaction with glycosaminoglycans, while the opposite face can bind fibronectin. Our findings reveal far greater diversity in the autotransporter β-helix than previously thought, and suggest that this domain can interact with host macromolecules. The relevance of these interactions during infection remains unclear.
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Affiliation(s)
- Jason J Paxman
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, VIC, Australia
| | - Alvin W Lo
- School of Chemistry and Molecular Biosciences, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Matthew J Sullivan
- School of Medical Science, and Menzies Health Institute Queensland, Griffith University, Gold Coast, 4222, QLD, Australia
| | - Santosh Panjikar
- Macromolecular Crystallography, Australian Synchrotron, Clayton, 3168, VIC, Australia
- Department of Molecular Biology and Biochemistry, Monash University, Melbourne, 3800, VIC, Australia
| | - Michael Kuiper
- Molecular & Materials Modelling group Data61, CSIRO, Docklands, Melbourne, 8012, VIC, Australia
| | - Andrew E Whitten
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, 2234, NSW, Australia
| | - Geqing Wang
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, VIC, Australia
| | - Chi-Hao Luan
- High Throughput Analysis Laboratory and Department of Molecular Biosciences, Northwestern University, Chicago, 60208, IL, USA
| | - Danilo G Moriel
- School of Chemistry and Molecular Biosciences, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Lendl Tan
- School of Chemistry and Molecular Biosciences, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Kate M Peters
- School of Chemistry and Molecular Biosciences, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Minh-Duy Phan
- School of Chemistry and Molecular Biosciences, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Christine L Gee
- Macromolecular Crystallography, Australian Synchrotron, Clayton, 3168, VIC, Australia
| | - Glen C Ulett
- School of Medical Science, and Menzies Health Institute Queensland, Griffith University, Gold Coast, 4222, QLD, Australia
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, 4072, QLD, Australia.
| | - Begoña Heras
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, VIC, Australia.
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18
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Chauhan N, Hatlem D, Orwick-Rydmark M, Schneider K, Floetenmeyer M, van Rossum B, Leo JC, Linke D. Insights into the autotransport process of a trimeric autotransporter, Yersinia Adhesin A (YadA). Mol Microbiol 2019; 111:844-862. [DOI: 10.1111/mmi.14195] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Nandini Chauhan
- Department of Biosciences; University of Oslo; Blindernveien 31 0371 Oslo Norway
- Max Planck Institute for Developmental Biology, Department 1; 72076 Tübingen Germany
| | - Daniel Hatlem
- Department of Biosciences; University of Oslo; Blindernveien 31 0371 Oslo Norway
| | | | - Kenneth Schneider
- Department of Biosciences; University of Oslo; Blindernveien 31 0371 Oslo Norway
| | - Matthias Floetenmeyer
- Max Planck Institute for Developmental Biology, Department 1; 72076 Tübingen Germany
- The Centre for Microscopy and Microanalysis, The University of Queensland; 4072 St. Lucia Queensland Australia
| | - Barth van Rossum
- Forschungsinstitut für Molekulare Pharmakologie; Department of NMR-Supported Structural Biology; Berlin Germany
| | - Jack C. Leo
- Department of Biosciences; University of Oslo; Blindernveien 31 0371 Oslo Norway
- Max Planck Institute for Developmental Biology, Department 1; 72076 Tübingen Germany
| | - Dirk Linke
- Department of Biosciences; University of Oslo; Blindernveien 31 0371 Oslo Norway
- Max Planck Institute for Developmental Biology, Department 1; 72076 Tübingen Germany
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19
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Abstract
Type V, or "autotransporter," secretion is a term used to refer to several simple protein export pathways that are found in a wide range of Gram-negative bacteria. Autotransporters are generally single polypeptides that consist of an extracellular ("passenger") domain and a β barrel domain that anchors the protein to the outer membrane (OM). Although it was originally proposed that the passenger domain is secreted through a channel formed solely by the covalently linked β barrel domain, experiments performed primarily on the type Va, or "classical," autotransporter pathway have challenged this hypothesis. Several lines of evidence strongly suggest that both the secretion of the passenger domain and the membrane integration of the β barrel domain are catalyzed by the barrel assembly machinery (Bam) complex, a conserved hetero-oligomer that plays an essential role in the assembly of most integral OM proteins. The secretion reaction appears to be driven at least in part by the folding of the passenger domain in the extracellular space. Although many aspects of autotransporter biogenesis remain to be elucidated, it will be especially interesting to determine whether the different classes of proteins that fall under the type V rubric-most of which have not been examined in detail-are assembled by the same basic mechanism as classical autotransporters.
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20
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Characterization of MCU-Binding Proteins MCUR1 and CCDC90B - Representatives of a Protein Family Conserved in Prokaryotes and Eukaryotic Organelles. Structure 2019; 27:464-475.e6. [PMID: 30612859 DOI: 10.1016/j.str.2018.11.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/12/2018] [Accepted: 11/06/2018] [Indexed: 12/14/2022]
Abstract
Membrane-bound coiled-coil proteins are important mediators of signaling, fusion, and scaffolding. Here, we delineate a heterogeneous group of trimeric membrane-anchored proteins in prokaryotes and eukaryotic organelles with a characteristic head-neck-stalk-anchor architecture, in which a membrane-anchored coiled-coil stalk projects an N-terminal head domain via a β-layer neck. Based on sequence analysis, we identify different types of head domains and determine crystal structures of two representatives, the archaeal protein Kcr-0859 and the human CCDC90B, which possesses the most widespread head type. Using mitochondrial calcium uniporter regulator 1 (MCUR1), the functionally characterized paralog of CCDC90B, we study the role of individual domains, and find that the head interacts directly with the mitochondrial calcium uniporter (MCU) and is destabilized upon Ca2+ binding. Our data provide structural details of a class of membrane-bound coiled-coil proteins and identify the conserved head domain of the most widespread type as a mediator of their function.
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21
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Nakatani H, Kanie J, Hori K. On‐fiber display of a functional peptide at sites distant from the cell surface using a long bacterionanofiber of a trimeric autotransporter adhesin. Biotechnol Bioeng 2018; 116:239-249. [DOI: 10.1002/bit.26857] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 10/20/2018] [Accepted: 10/30/2018] [Indexed: 01/08/2023]
Affiliation(s)
- Hajime Nakatani
- Department of Biomolecular EngineeringGraduate School of Engineering, Nagoya University, Furo‐cho, Chikusa‐kuNagoya Japan
| | - Junichi Kanie
- Department of Biomolecular EngineeringGraduate School of Engineering, Nagoya University, Furo‐cho, Chikusa‐kuNagoya Japan
| | - Katsutoshi Hori
- Department of Biomolecular EngineeringGraduate School of Engineering, Nagoya University, Furo‐cho, Chikusa‐kuNagoya Japan
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22
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Solanki V, Tiwari M, Tiwari V. Host-bacteria interaction and adhesin study for development of therapeutics. Int J Biol Macromol 2018; 112:54-64. [PMID: 29414732 DOI: 10.1016/j.ijbiomac.2018.01.151] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/17/2018] [Accepted: 01/21/2018] [Indexed: 12/15/2022]
Abstract
Host-pathogen interaction is one of the most important areas of study to understand the adhesion of the pathogen to the host organisms. To adhere on the host cell surface, bacteria assemble the diverse adhesive structures on its surface, which play a foremost role in targeting to the host cell. We have highlighted different bacterial adhesins which are either protein mediated or glycan mediated. The present article listed examples of different bacterial adhesin proteins involved in the interactions with their host, types and subtypes of the fimbriae and non-fimbriae bacterial adhesins. Different bacterial surface adhesin subunits interact with host via different host surface biomolecules. We have also discussed the interactome of some of the pathogens with their host. Therefore, the present study will help researchers to have a detailed understanding of different interacting bacterial adhesins and henceforth, develop new therapies, adhesin specific antibodies and vaccines, which can effectively control pathogenicity of the pathogens.
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Affiliation(s)
- Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India.
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23
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Sikdar R, Peterson JH, Anderson DE, Bernstein HD. Folding of a bacterial integral outer membrane protein is initiated in the periplasm. Nat Commun 2017; 8:1309. [PMID: 29101319 PMCID: PMC5670179 DOI: 10.1038/s41467-017-01246-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/30/2017] [Indexed: 02/06/2023] Open
Abstract
The Bam complex promotes the insertion of β-barrel proteins into the bacterial outer membrane, but it is unclear whether it threads β-strands into the lipid bilayer in a stepwise fashion or catalyzes the insertion of pre-folded substrates. Here, to distinguish between these two possibilities, we analyze the biogenesis of UpaG, a trimeric autotransporter adhesin (TAA). TAAs consist of three identical subunits that together form a single β-barrel domain and an extracellular coiled-coil (“passenger”) domain. Using site-specific photocrosslinking to obtain spatial and temporal insights into UpaG assembly, we show that UpaG β-barrel segments fold into a trimeric structure in the periplasm that persists until the termination of passenger-domain translocation. In addition to obtaining evidence that at least some β-barrel proteins begin to fold before they interact with the Bam complex, we identify several discrete steps in the assembly of a poorly characterized class of virulence factors. The Bam complex promotes the insertion of β-barrel proteins (such as UpaG, a trimeric autotransporter adhesin) into the bacterial outer membrane. Here, Sikdar et al. show that UpaG β-barrel segments fold into a trimeric structure in the periplasm before they interact with the Bam complex.
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Affiliation(s)
- Rakesh Sikdar
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Janine H Peterson
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - D Eric Anderson
- Advanced Mass Spectrometry Facility, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Harris D Bernstein
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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24
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Wright J, Thomsen M, Kolodziejczyk R, Ridley J, Sinclair J, Carrington G, Singh B, Riesbeck K, Goldman A. The crystal structure of PD1, a Haemophilus surface fibril domain. Acta Crystallogr F Struct Biol Commun 2017; 73:101-108. [PMID: 28177321 PMCID: PMC5297931 DOI: 10.1107/s2053230x17001406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/27/2017] [Indexed: 11/12/2022] Open
Abstract
The Haemophilus surface fibril (Hsf) is an unusually large trimeric autotransporter adhesin (TAA) expressed by the most virulent strains of H. influenzae. Hsf is known to mediate adhesion between pathogen and host, allowing the establishment of potentially deadly diseases such as epiglottitis, meningitis and pneumonia. While recent research has suggested that this TAA might adopt a novel `hairpin-like' architecture, the characterization of Hsf has been limited to in silico modelling and electron micrographs, with no high-resolution structural data available. Here, the crystal structure of Hsf putative domain 1 (PD1) is reported at 3.3 Å resolution. The structure corrects the previous domain annotation by revealing the presence of an unexpected N-terminal TrpRing domain. PD1 represents the first Hsf domain to be solved, and thus paves the way for further research on the `hairpin-like' hypothesis.
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Affiliation(s)
- Jack Wright
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, England
| | - Maren Thomsen
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, England
| | - Robert Kolodziejczyk
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, England
- Pure Biologics Ltd, Dunska 11, 54-427 Wroclaw, Poland
| | - Joshua Ridley
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, England
| | - Jessica Sinclair
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, England
| | - Glenn Carrington
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, England
| | - Birendra Singh
- Department of Clinical Microbiology, Lund University, Jan Waldenströms gata 59, SE-205 02 Malmö, Sweden
| | - Kristian Riesbeck
- Department of Clinical Microbiology, Lund University, Jan Waldenströms gata 59, SE-205 02 Malmö, Sweden
| | - Adrian Goldman
- Astbury Centre for Structural Molecular Biology, School of Biomedical Science, University of Leeds, Leeds LS2 9JT, England
- Division of Biochemistry, University of Helsinki, FIN-00014 Helsinki, Finland
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25
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Abstract
Coiled coils appear in countless structural contexts, as appendages to small proteins, as parts of multi-domain proteins, and as building blocks of filaments. Although their structure is unpretentious and their basic properties are understood in great detail, the spectrum of functional properties they provide in different proteins has become increasingly complex. This chapter aims to depict this functional spectrum, to identify common themes and their molecular basis, with an emphasis on new insights gained into dynamic aspects.
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Affiliation(s)
- Marcus D Hartmann
- Max Planck Institute for Developmental Biology, Spemannstraße 35, 72076, Tübingen, Germany.
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26
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The Helicobacter pylori Autotransporter ImaA Tempers the Bacterium's Interaction with α5β1 Integrin. Infect Immun 2016; 85:IAI.00450-16. [PMID: 27795352 DOI: 10.1128/iai.00450-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/07/2016] [Indexed: 02/07/2023] Open
Abstract
The human pathogen Helicobacter pylori uses the host receptor α5β1 integrin to trigger inflammation in host cells via its cag pathogenicity island (cag PAI) type IV secretion system (T4SS). Here, we report that the H. pylori ImaA protein (HP0289) decreases the action of the cag PAI T4SS via tempering the bacterium's interaction with α5β1 integrin. Previously, imaA-null mutants were found to induce an elevated inflammatory response that was dependent on the cag PAI T4SS; here we extend those findings to show that the elevated response is independent of the CagA effector protein. To understand how ImaA could be affecting cag PAI T4SS activity at the host cell interface, we utilized the Phyre structural threading program and found that ImaA has a region with remote homology to bacterial integrin-binding proteins. This region was required for ImaA function. Unexpectedly, we observed that imaA mutants bound higher levels of α5β1 integrin than wild-type H. pylori, an outcome that required the predicted integrin-binding homology region of ImaA. Lastly, we report that ImaA directly affected the amount of host cell β1 integrin but not other cellular integrins. Our results thus suggest a model in which H. pylori employs ImaA to regulate interactions between integrin and the T4SS and thus alter the host inflammatory strength.
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27
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Abstract
Type V secretion denotes a variety of secretion systems that cross the outer membrane in Gram-negative bacteria but that depend on the Sec machinery for transport through the inner membrane. They are possibly the simplest bacterial secretion systems, because they consist only of a single polypeptide chain (or two chains in the case of two-partner secretion). Their seemingly autonomous transport through the outer membrane has led to the term "autotransporters" for various subclasses of type V secretion. In this chapter, we review the structure and function of these transporters and review recent findings on additional factors involved in the secretion process, which have put the term "autotransporter" to debate.
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28
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Lupas AN, Bassler J. Coiled Coils - A Model System for the 21st Century. Trends Biochem Sci 2016; 42:130-140. [PMID: 27884598 DOI: 10.1016/j.tibs.2016.10.007] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 10/25/2016] [Indexed: 01/01/2023]
Abstract
α-Helical coiled coils were described more than 60 years ago as simple, repetitive structures mediating oligomerization and mechanical stability. Over the past 20 years, however, they have emerged as one of the most diverse protein folds in nature, enabling many biological functions beyond mechanical rigidity, such as membrane fusion, signal transduction, and solute transport. Despite this great diversity, their structures can be described by parametric equations, making them uniquely suited for rational protein design. Far from having been exhausted as a source of structural insight and a basis for functional engineering, coiled coils are poised to become even more important for protein science in the coming decades.
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Affiliation(s)
- Andrei N Lupas
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
| | - Jens Bassler
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
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29
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Ishikawa M, Yoshimoto S, Hayashi A, Kanie J, Hori K. Discovery of a novel periplasmic protein that forms a complex with a trimeric autotransporter adhesin and peptidoglycan. Mol Microbiol 2016; 101:394-410. [PMID: 27074146 DOI: 10.1111/mmi.13398] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/06/2016] [Indexed: 12/01/2022]
Abstract
Trimeric autotransporter adhesins (TAAs), fibrous proteins on the cell surface of Gram-negative bacteria, have attracted attention as virulence factors. However, little is known about the mechanism of their biogenesis. AtaA, a TAA of Acinetobacter sp. Tol 5, confers nonspecific, high adhesiveness to bacterial cells. We identified a new gene, tpgA, which forms a single operon with ataA and encodes a protein comprising two conserved protein domains identified by Pfam: an N-terminal SmpA/OmlA domain and a C-terminal OmpA_C-like domain with a peptidoglycan (PGN)-binding motif. Cell fractionation and a pull-down assay showed that TpgA forms a complex with AtaA, anchoring it to the outer membrane (OM). Isolation of total PGN-associated proteins showed TpgA binding to PGN. Disruption of tpgA significantly decreased the adhesiveness of Tol 5 because of a decrease in surface-displayed AtaA, suggesting TpgA involvement in AtaA secretion. This is reminiscent of SadB, which functions as a specific chaperone for SadA, a TAA in Salmonella species; however, SadB anchors to the inner membrane, whereas TpgA anchors to the OM through AtaA. The genetic organization encoding the TAA-TpgA-like protein cassette can be found in diverse Gram-negative bacteria, suggesting a common contribution of TpgA homologues to TAA biogenesis.
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Affiliation(s)
- Masahito Ishikawa
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan
| | - Shogo Yoshimoto
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan
| | - Ayumi Hayashi
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan
| | - Junichi Kanie
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan
| | - Katsutoshi Hori
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan
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Hartmann MD, Mendler CT, Bassler J, Karamichali I, Ridderbusch O, Lupas AN, Hernandez Alvarez B. α/β coiled coils. eLife 2016; 5. [PMID: 26771248 PMCID: PMC4786415 DOI: 10.7554/elife.11861] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/14/2016] [Indexed: 01/10/2023] Open
Abstract
Coiled coils are the best-understood protein fold, as their backbone structure can uniquely be described by parametric equations. This level of understanding has allowed their manipulation in unprecedented detail. They do not seem a likely source of surprises, yet we describe here the unexpected formation of a new type of fiber by the simple insertion of two or six residues into the underlying heptad repeat of a parallel, trimeric coiled coil. These insertions strain the supercoil to the breaking point, causing the local formation of short β-strands, which move the path of the chain by 120° around the trimer axis. The result is an α/β coiled coil, which retains only one backbone hydrogen bond per repeat unit from the parent coiled coil. Our results show that a substantially novel backbone structure is possible within the allowed regions of the Ramachandran space with only minor mutations to a known fold.
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Affiliation(s)
- Marcus D Hartmann
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Claudia T Mendler
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Jens Bassler
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Ioanna Karamichali
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Oswin Ridderbusch
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Andrei N Lupas
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Birte Hernandez Alvarez
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
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31
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Koiwai K, Hartmann MD, Linke D, Lupas AN, Hori K. Structural Basis for Toughness and Flexibility in the C-terminal Passenger Domain of an Acinetobacter Trimeric Autotransporter Adhesin. J Biol Chem 2015; 291:3705-24. [PMID: 26698633 DOI: 10.1074/jbc.m115.701698] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Indexed: 11/06/2022] Open
Abstract
Trimeric autotransporter adhesins (TAAs) on the cell surface of Gram-negative pathogens mediate bacterial adhesion to host cells and extracellular matrix proteins. However, AtaA, a TAA in the nonpathogenic Acinetobacter sp. strain Tol 5, shows nonspecific high adhesiveness to abiotic material surfaces as well as to biotic surfaces. It consists of a passenger domain secreted by the C-terminal transmembrane anchor domain (TM), and the passenger domain contains an N-terminal head, N-terminal stalk, C-terminal head (Chead), and C-terminal stalk (Cstalk). The Chead-Cstalk-TM fragment, which is conserved in many Acinetobacter TAAs, has by itself the head-stalk-anchor architecture of a complete TAA. Here, we show the crystal structure of the Chead-Cstalk fragment, AtaA_C-terminal passenger domain (CPSD), providing the first view of several conserved TAA domains. The YadA-like head (Ylhead) of the fragment is capped by a unique structure (headCap), composed of three β-hairpins and a connector motif; it also contains a head insert motif (HIM1) before its last inner β-strand. The headCap, Ylhead, and HIM1 integrally form a stable Chead structure. Some of the major domains of the CPSD fragment are inherently flexible and provide bending sites for the fiber between segments whose toughness is ensured by topological chain exchange and hydrophobic core formation inside the trimer. Thus, although adherence assays using in-frame deletion mutants revealed that the characteristic adhesive sites of AtaA reside in its N-terminal part, the flexibility and toughness of the CPSD part provide the resilience that enables the adhesive properties of the full-length fiber across a wide range of conditions.
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Affiliation(s)
- Kotaro Koiwai
- From the Department of Biotechnology, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan, the Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan
| | - Marcus D Hartmann
- the Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany, and
| | - Dirk Linke
- the Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany, and the Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Andrei N Lupas
- the Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany, and
| | - Katsutoshi Hori
- From the Department of Biotechnology, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan,
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32
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Mohamed A, Johnston RN, Shmulevitz M. Potential for Improving Potency and Specificity of Reovirus Oncolysis with Next-Generation Reovirus Variants. Viruses 2015; 7:6251-78. [PMID: 26633466 PMCID: PMC4690860 DOI: 10.3390/v7122936] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 11/10/2015] [Accepted: 11/18/2015] [Indexed: 12/16/2022] Open
Abstract
Viruses that specifically replicate in tumor over normal cells offer promising cancer therapies. Oncolytic viruses (OV) not only kill the tumor cells directly; they also promote anti-tumor immunotherapeutic responses. Other major advantages of OVs are that they dose-escalate in tumors and can be genetically engineered to enhance potency and specificity. Unmodified wild type reovirus is a propitious OV currently in phase I–III clinical trials. This review summarizes modifications to reovirus that may improve potency and/or specificity during oncolysis. Classical genetics approaches have revealed reovirus variants with improved adaptation towards tumors or with enhanced ability to establish specific steps of virus replication and cell killing among transformed cells. The recent emergence of a reverse genetics system for reovirus has provided novel strategies to fine-tune reovirus proteins or introduce exogenous genes that could promote oncolytic activity. Over the next decade, these findings are likely to generate better-optimized second-generation reovirus vectors and improve the efficacy of oncolytic reotherapy.
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Affiliation(s)
- Adil Mohamed
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2E1, Canada.
| | - Randal N Johnston
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
| | - Maya Shmulevitz
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2E1, Canada.
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33
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Gourlay LJ, Peano C, Deantonio C, Perletti L, Pietrelli A, Villa R, Matterazzo E, Lassaux P, Santoro C, Puccio S, Sblattero D, Bolognesi M. Selecting soluble/foldable protein domains through single-gene or genomic ORF filtering: structure of the head domain of Burkholderia pseudomallei antigen BPSL2063. ACTA ACUST UNITED AC 2015; 71:2227-35. [PMID: 26527140 DOI: 10.1107/s1399004715015680] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/21/2015] [Indexed: 11/10/2022]
Abstract
The 1.8 Å resolution crystal structure of a conserved domain of the potential Burkholderia pseudomallei antigen and trimeric autotransporter BPSL2063 is presented as a structural vaccinology target for melioidosis vaccine development. Since BPSL2063 (1090 amino acids) hosts only one conserved domain, and the expression/purification of the full-length protein proved to be problematic, a domain-filtering library was generated using β-lactamase as a reporter gene to select further BPSL2063 domains. As a result, two domains (D1 and D2) were identified and produced in soluble form in Escherichia coli. Furthermore, as a general tool, a genomic open reading frame-filtering library from the B. pseudomallei genome was also constructed to facilitate the selection of domain boundaries from the entire ORFeome. Such an approach allowed the selection of three potential protein antigens that were also produced in soluble form. The results imply the further development of ORF-filtering methods as a tool in protein-based research to improve the selection and production of soluble proteins or domains for downstream applications such as X-ray crystallography.
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Affiliation(s)
- Louise J Gourlay
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
| | - Clelia Peano
- Institute of Biomedical Technologies, National Research Council, Via Fratelli Cervi 93, 20090 Segrate, Italy
| | - Cecilia Deantonio
- Department of Health Sciences and IRCAD, University of Eastern Piedmont, Via Solaroli 17, 28100 Novara, Italy
| | - Lucia Perletti
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
| | - Alessandro Pietrelli
- Institute of Biomedical Technologies, National Research Council, Via Fratelli Cervi 93, 20090 Segrate, Italy
| | - Riccardo Villa
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
| | - Elena Matterazzo
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
| | - Patricia Lassaux
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
| | - Claudio Santoro
- Department of Health Sciences and IRCAD, University of Eastern Piedmont, Via Solaroli 17, 28100 Novara, Italy
| | - Simone Puccio
- Institute of Biomedical Technologies, National Research Council, Via Fratelli Cervi 93, 20090 Segrate, Italy
| | - Daniele Sblattero
- Department of Life Sciences, University of Trieste, Via Weiss 2, 34128 Trieste, Italy
| | - Martino Bolognesi
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
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34
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Chahales P, Thanassi DG. Structure, Function, and Assembly of Adhesive Organelles by Uropathogenic Bacteria. Microbiol Spectr 2015; 3:10.1128/microbiolspec.UTI-0018-2013. [PMID: 26542038 PMCID: PMC4638162 DOI: 10.1128/microbiolspec.uti-0018-2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Indexed: 01/02/2023] Open
Abstract
Bacteria assemble a wide range of adhesive proteins, termed adhesins, to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are critical for early stages of infection, allowing the bacteria to initiate contact with host cells, colonize different tissues, and establish a foothold within the host. The adhesins expressed by a pathogen are also critical for bacterial-bacterial interactions and the formation of bacterial communities, including biofilms. The ability to adhere to host tissues is particularly important for bacteria that colonize sites such as the urinary tract, where the flow of urine functions to maintain sterility by washing away non-adherent pathogens. Adhesins vary from monomeric proteins that are directly anchored to the bacterial surface to polymeric, hair-like fibers that extend out from the cell surface. These latter fibers are termed pili or fimbriae, and were among the first identified virulence factors of uropathogenic Escherichia coli. Studies since then have identified a range of both pilus and non-pilus adhesins that contribute to bacterial colonization of the urinary tract, and have revealed molecular details of the structures, assembly pathways, and functions of these adhesive organelles. In this review, we describe the different types of adhesins expressed by both Gram-negative and Gram-positive uropathogens, what is known about their structures, how they are assembled on the bacterial surface, and the functions of specific adhesins in the pathogenesis of urinary tract infections.
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Affiliation(s)
- Peter Chahales
- Center for Infectious Diseases and Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794
| | - David G Thanassi
- Center for Infectious Diseases and Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794
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35
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Virulent Burkholderia species mimic host actin polymerases to drive actin-based motility. Cell 2015; 161:348-60. [PMID: 25860613 DOI: 10.1016/j.cell.2015.02.044] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/22/2014] [Accepted: 02/05/2015] [Indexed: 11/23/2022]
Abstract
Burkholderia pseudomallei and B. mallei are bacterial pathogens that cause melioidosis and glanders, whereas their close relative B. thailandensis is non-pathogenic. All use the trimeric autotransporter BimA to facilitate actin-based motility, host cell fusion, and dissemination. Here, we show that BimA orthologs mimic different host actin-polymerizing proteins. B. thailandensis BimA activates the host Arp2/3 complex. In contrast, B. pseudomallei and B. mallei BimA mimic host Ena/VASP actin polymerases in their ability to nucleate, elongate, and bundle filaments by associating with barbed ends, as well as in their use of WH2 motifs and oligomerization for activity. Mechanistic differences among BimA orthologs resulted in distinct actin filament organization and motility parameters, which affected the efficiency of cell fusion during infection. Our results identify bacterial Ena/VASP mimics and reveal that pathogens imitate the full spectrum of host actin-polymerizing pathways, suggesting that mimicry of different polymerization mechanisms influences key parameters of infection.
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36
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Qin W, Wang L, Lei L. New findings on the function and potential applications of the trimeric autotransporter adhesin. Antonie van Leeuwenhoek 2015; 108:1-14. [PMID: 26014492 DOI: 10.1007/s10482-015-0477-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 05/08/2015] [Indexed: 11/27/2022]
Abstract
Trimeric autotransporter adhesins (TAAs) are located on the surface of many pathogenic Gram-negative bacteria. TAAs belong to the autotransporter protein family and consist of three identical monomers. These obligate homotrimeric proteins are secreted through the bacterial type Vc secretion system and share a common molecular organization that each monomer consists of a N-terminal "passenger" domain and a C-terminal translocation domain. TAAs are important virulence factors that are involved in bacterial life cycle and participate in mediating infection, invasion, dissemination and evasion of host immune responses. TAAs have also proved to be useful for many applications, such as vaccines and disease biomarkers. We here mainly focused on new findings on bio-function and application of TAAs in addition to their common structure and secretion mechanisms.
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Affiliation(s)
- Wanhai Qin
- College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, China,
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37
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38
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Abstract
Research in Tübingen on bacterial cell walls began in 1951 and continues to this day. The studies over the decades reflect the development in the field, which was strongly influenced by the design of suitable biochemical and genetic methods used to unravel the highly complex envelope structure. At the beginning of this period, improper crude extraction and solubilization methods were employed in an attempt to isolate pure components. Nevertheless, progress was steady and culminated in major insights into the structure and function of individual cell wall components and the cell wall as a whole. The "cell wall" has various definitions. In this short overview, the term includes the cell wall of gram-positive bacteria in the strict sense, and also the outer membrane, the murein (peptidoglycan) and the outer membrane of gram-negative bacteria and the cytoplasmic membranes.
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Affiliation(s)
- Volkmar Braun
- Max Planck Institute for Developmental Biology, Department of Protein Evolution, Spemannstrasse 35, 72076 Tübingen, Germany.
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39
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Bassler J, Hernandez Alvarez B, Hartmann MD, Lupas AN. A domain dictionary of trimeric autotransporter adhesins. Int J Med Microbiol 2014; 305:265-75. [PMID: 25583454 DOI: 10.1016/j.ijmm.2014.12.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Trimeric autotransporter adhesins (TAAs) are modular, highly repetitive outer membrane proteins that mediate adhesion to external surfaces in many Gram-negative bacteria. In recent years, several TAAs have been investigated in considerable detail, also at the structural level. However, in their vast majority, putative TAAs in prokaryotic genomes remain poorly annotated, due to their sequence diversity and changeable domain architecture. In order to achieve an automated annotation of these proteins that is both detailed and accurate we have taken a domain dictionary approach, in which we identify recurrent domains by sequence comparisons, produce bioinformatic descriptors for each domain type, and connect these to structural information where available. We implemented this approach in a web-based platform, daTAA, in 2008 and demonstrated its applicability by reconstructing the complete fiber structure of a TAA conserved in enterobacteria. Here we review current knowledge on the domain structure of TAAs.
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Affiliation(s)
- Jens Bassler
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, Spemannstr. 35, 72076 Tuebingen, Germany
| | - Birte Hernandez Alvarez
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, Spemannstr. 35, 72076 Tuebingen, Germany
| | - Marcus D Hartmann
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, Spemannstr. 35, 72076 Tuebingen, Germany
| | - Andrei N Lupas
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, Spemannstr. 35, 72076 Tuebingen, Germany.
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40
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Kovtun O, Tillu VA, Jung W, Leneva N, Ariotti N, Chaudhary N, Mandyam RA, Ferguson C, Morgan GP, Johnston WA, Harrop SJ, Alexandrov K, Parton RG, Collins BM. Structural insights into the organization of the cavin membrane coat complex. Dev Cell 2014; 31:405-19. [PMID: 25453557 DOI: 10.1016/j.devcel.2014.10.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 08/29/2014] [Accepted: 10/02/2014] [Indexed: 01/10/2023]
Abstract
Caveolae are cell-surface membrane invaginations that play critical roles in cellular processes including signaling and membrane homeostasis. The cavin proteins, in cooperation with caveolins, are essential for caveola formation. Here we show that a minimal N-terminal domain of the cavins, termed HR1, is required and sufficient for their homo- and hetero-oligomerization. Crystal structures of the mouse cavin1 and zebrafish cavin4a HR1 domains reveal highly conserved trimeric coiled-coil architectures, with intersubunit interactions that determine the specificity of cavin-cavin interactions. The HR1 domain contains a basic surface patch that interacts with polyphosphoinositides and coordinates with additional membrane-binding sites within the cavin C terminus to facilitate membrane association and remodeling. Electron microscopy of purified cavins reveals the existence of large assemblies, composed of a repeating rod-like structural element, and we propose that these structures polymerize through membrane-coupled interactions to form the unique striations observed on the surface of caveolae in vivo.
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Affiliation(s)
- Oleksiy Kovtun
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Vikas A Tillu
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - WooRam Jung
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Natalya Leneva
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Natasha Chaudhary
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Ramya A Mandyam
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Garry P Morgan
- Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Wayne A Johnston
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Stephen J Harrop
- School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Kirill Alexandrov
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia; Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
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41
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Haemophilus influenzae surface fibril (Hsf) is a unique twisted hairpin-like trimeric autotransporter. Int J Med Microbiol 2014; 305:27-37. [PMID: 25465160 DOI: 10.1016/j.ijmm.2014.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 10/08/2014] [Accepted: 10/18/2014] [Indexed: 11/21/2022] Open
Abstract
The Haemophilus surface fibril (Hsf) is an extraordinary large (2413 amino acids) trimeric autotransporter, present in all encapsulated Haemophilus influenzae. It contributes to virulence by directly functioning as an adhesin. Furthermore, Hsf recruits the host factor vitronectin thereby inhibiting the host innate immune response resulting in enhanced survival in serum. Here we observed by electron microscopy that Hsf appears as an 100 nm long fibril at the bacterial surface albeit the length is approximately 200 nm according to a bioinformatics based model. To unveil this discrepancy, we denaturated Hsf at the surface of Hib by using guanidine hydrochloride (GuHCl). Partial denaturation induced in the presence of GuHCl unfolded the Hsf molecules, and resulted in an increased length of fibres in comparison to the native trimeric form. Importantly, our findings were also verified by E. coli expressing Hsf at its surface. In addition, a set of Hsf-specific peptide antibodies also indicated that the N-terminal of Hsf is located near the C-terminal at the base of the fibril. Taken together, our results demonstrated that Hsf is not a straight molecule but is folded and doubled over. This is the first report that provides the unique structural features of the trimeric autotransporter Hsf.
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42
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Jaglic Z, Desvaux M, Weiss A, Nesse LL, Meyer RL, Demnerova K, Schmidt H, Giaouris E, Sipailiene A, Teixeira P, Kačániová M, Riedel CU, Knøchel S. Surface adhesins and exopolymers of selected foodborne pathogens. MICROBIOLOGY-SGM 2014; 160:2561-2582. [PMID: 25217529 DOI: 10.1099/mic.0.075887-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ability of bacteria to bind different compounds and to adhere to biotic and abiotic surfaces provides them with a range of advantages, such as colonization of various tissues, internalization, avoidance of an immune response, and survival and persistence in the environment. A variety of bacterial surface structures are involved in this process and these promote bacterial adhesion in a more or less specific manner. In this review, we will focus on those surface adhesins and exopolymers in selected foodborne pathogens that are involved mainly in primary adhesion. Their role in biofilm development will also be considered when appropriate. Both the clinical impact and the implications for food safety of such adhesion will be discussed.
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Affiliation(s)
- Zoran Jaglic
- Veterinary Research Institute, Brno, Czech Republic
| | - Mickaël Desvaux
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France
| | - Agnes Weiss
- Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany
| | | | - Rikke L Meyer
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Katerina Demnerova
- Institute of Chemical Technology, Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, Technicka 5, Prague, 166 28, Czech Republic
| | - Herbert Schmidt
- Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany
| | - Efstathios Giaouris
- Department of Food Science and Nutrition, Faculty of the Environment, University of the Aegean, 81400 Myrina, Lemnos Island, Greece
| | | | - Pilar Teixeira
- CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal
| | | | - Christian U Riedel
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Susanne Knøchel
- Department of Food Science, University of Copenhagen, Rolighedsvej 30, Frederiksberg C 1958, Denmark
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43
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Deiss S, Hernandez Alvarez B, Bär K, Ewers CP, Coles M, Albrecht R, Hartmann MD. Your personalized protein structure: Andrei N. Lupas fused to GCN4 adaptors. J Struct Biol 2014; 186:380-5. [DOI: 10.1016/j.jsb.2014.01.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/22/2014] [Accepted: 01/23/2014] [Indexed: 01/07/2023]
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44
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Heterologous expression of Bartonella adhesin A in Escherichia coli by exchange of trimeric autotransporter adhesin domains results in enhanced adhesion properties and a pathogenic phenotype. J Bacteriol 2014; 196:2155-65. [PMID: 24682330 DOI: 10.1128/jb.01461-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Human-pathogenic Bartonella henselae causes cat scratch disease and vasculoproliferative disorders. An important pathogenicity factor of B. henselae is the trimeric autotransporter adhesin (TAA) Bartonella adhesin A (BadA), which is modularly constructed, consisting of a head, a long and repetitive neck-stalk module, and a membrane anchor. BadA is involved in bacterial autoagglutination, binding to extracellular matrix proteins and host cells, and in proangiogenic reprogramming. The slow growth of B. henselae and limited tools for genetic manipulation are obstacles for detailed examination of BadA and its domains. Here, we established a recombinant expression system for BadA mutants in Escherichia coli allowing functional analysis of particular BadA domains. Using a BadA mutant lacking 21 neck-stalk repeats (BadA HN23), the BadA HN23 signal sequence was exchanged with that of E. coli OmpA, and the BadA membrane anchor was additionally replaced with that of Yersinia adhesin A (YadA). Constructs were cloned in E. coli, and hybrid protein expression was detected by immunoblotting, fluorescence microscopy, and flow cytometry. Functional analysis revealed that BadA hybrid proteins mediate autoagglutination and binding to collagen and endothelial cells. In vivo, expression of this BadA construct correlated with higher pathogenicity of E. coli in a Galleria mellonella infection model.
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45
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Characterization of BCAM0224, a multifunctional trimeric autotransporter from the human pathogen Burkholderia cenocepacia. J Bacteriol 2014; 196:1968-79. [PMID: 24659767 DOI: 10.1128/jb.00061-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the trimeric autotransporter adhesin (TAA) family play a crucial role in adhesion of Gram-negative pathogens to host cells. Moreover, these proteins are multifunctional virulence factors involved in several other biological traits, including invasion into host cells and evasion of the host immune system. In cystic fibrosis epidemic Burkholderia cenocepacia strain J2315, we identified a unique TAA (BCAM0224)-encoding gene, previously described as being implicated in virulence. Here, we characterized this multifunctional protein, trying to establish its role in B. cenocepacia pathogenicity. We show that BCAM0224 occurs on the bacterial surface and adopts a trimeric conformation. Furthermore, we demonstrated that BCAM0224 is needed for earlier stages of biofilm formation and is required for swarming motility. In addition, BCAM0224 plays an important role in evasion of the human innate immune system, providing resistance against the bactericidal activity of serum via the complement classical pathway. Finally, BCAM0224 mediates bacterial adhesion to and invasion of cultured human bronchial epithelial cells. Together, these data reveal the high versatility of the BCAM0224 protein as a virulence factor in the pathogenic bacterium B. cenocepacia.
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46
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The Haemophilus cryptic genospecies Cha adhesin has at least two variants that differ in host cell binding, bacterial aggregation, and biofilm formation properties. J Bacteriol 2014; 196:1780-8. [PMID: 24584499 DOI: 10.1128/jb.01409-13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Haemophilus cryptic genospecies (HCG) causes genital tract infections in pregnant and postpartum women and respiratory infections in neonates. The major surface adhesin in HCG is called Cha, which mediates bacterial adherence to cultured human epithelial cells. In this study, we report that there are two antigenically distinct variants of Cha, dubbed Cha1 and Cha2. These variants are encoded by the same genetic locus in diverse strains and have nearly identical N-terminal export and C-terminal surface anchoring domains but significantly different internal adhesive domains. Based on the comparison of derivatives of a laboratory strain of Haemophilus influenzae expressing either surface-associated Cha1 or surface-associated Cha2, Cha1 mediates a higher level of adherence to cultured human epithelial cells and Cha2 mediates a higher level of adherence to abiotic surfaces. We hypothesize that variation in the Cha1 and Cha2 internal region results in changes in binding specificity or binding affinity and may be associated with adaptation to different host environments during colonization and disease.
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47
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Grin I, Hartmann MD, Sauer G, Hernandez Alvarez B, Schütz M, Wagner S, Madlung J, Macek B, Felipe-Lopez A, Hensel M, Lupas A, Linke D. A trimeric lipoprotein assists in trimeric autotransporter biogenesis in enterobacteria. J Biol Chem 2013; 289:7388-98. [PMID: 24369174 PMCID: PMC3953254 DOI: 10.1074/jbc.m113.513275] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Trimeric autotransporter adhesins (TAAs) are important virulence factors of many Gram-negative bacterial pathogens. TAAs form fibrous, adhesive structures on the bacterial cell surface. Their N-terminal extracellular domains are exported through a C-terminal membrane pore; the insertion of the pore domain into the bacterial outer membrane follows the rules of β-barrel transmembrane protein biogenesis and is dependent on the essential Bam complex. We have recently described the full fiber structure of SadA, a TAA of unknown function in Salmonella and other enterobacteria. In this work, we describe the structure and function of SadB, a small inner membrane lipoprotein. The sadB gene is located in an operon with sadA; orthologous operons are only found in enterobacteria, whereas other TAAs are not typically associated with lipoproteins. Strikingly, SadB is also a trimer, and its co-expression with SadA has a direct influence on SadA structural integrity. This is the first report of a specific export factor of a TAA, suggesting that at least in some cases TAA autotransport is assisted by additional periplasmic proteins.
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Affiliation(s)
- Iwan Grin
- From the Max Planck Institut für Entwicklungsbiologie, 72076 Tübingen
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48
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The antigen 43 structure reveals a molecular Velcro-like mechanism of autotransporter-mediated bacterial clumping. Proc Natl Acad Sci U S A 2013; 111:457-62. [PMID: 24335802 DOI: 10.1073/pnas.1311592111] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Aggregation and biofilm formation are critical mechanisms for bacterial resistance to host immune factors and antibiotics. Autotransporter (AT) proteins, which represent the largest group of outer-membrane and secreted proteins in Gram-negative bacteria, contribute significantly to these phenotypes. Despite their abundance and role in bacterial pathogenesis, most AT proteins have not been structurally characterized, and there is a paucity of detailed information with regard to their mode of action. Here we report the structure-function relationships of Antigen 43 (Ag43a), a prototypic self-associating AT protein from uropathogenic Escherichia coli. The functional domain of Ag43a displays a twisted L-shaped β-helical structure firmly stabilized by a 3D hydrogen-bonded scaffold. Notably, the distinctive Ag43a L shape facilitates self-association and cell aggregation. Combining all our data, we define a molecular "Velcro-like" mechanism of AT-mediated bacterial clumping, which can be tailored to fit different bacterial lifestyles such as the formation of biofilms.
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49
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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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50
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El-Kirat-Chatel S, Mil-Homens D, Beaussart A, Fialho AM, Dufrêne YF. Single-molecule atomic force microscopy unravels the binding mechanism of aBurkholderia cenocepaciatrimeric autotransporter adhesin. Mol Microbiol 2013; 89:649-59. [DOI: 10.1111/mmi.12301] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Sofiane El-Kirat-Chatel
- Université catholique de Louvain; Institute of Life Sciences; Croix du Sud, 1, bte L7.04.01.; B-1348; Louvain-la-Neuve; Belgium
| | - Dalila Mil-Homens
- IBB-Institute for Biotechnology and Bioengineering; Instituto Superior Técnico; Lisbon; 1049-001; Portugal
| | - Audrey Beaussart
- Université catholique de Louvain; Institute of Life Sciences; Croix du Sud, 1, bte L7.04.01.; B-1348; Louvain-la-Neuve; Belgium
| | | | - Yves F. Dufrêne
- Université catholique de Louvain; Institute of Life Sciences; Croix du Sud, 1, bte L7.04.01.; B-1348; Louvain-la-Neuve; Belgium
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