1
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Bhatt S, Faridi N, Raj SMP, Agarwal A, Punetha M. Recent advances in immuno-based methods for the detection of Ralstonia solanacearum. J Microbiol Methods 2024; 217-218:106889. [PMID: 38211840 DOI: 10.1016/j.mimet.2024.106889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/13/2024]
Abstract
Ralstonia solanacearum (RS) is a widely recognized phytopathogenic bacterium which is responsible for causing devastating losses in a wide range of economically significant crops. Timely and accurate detection of this pathogen is pivotal to implementing effective disease management strategies and preventing crop losses. This review provides a comprehensive overview of recent advances in immuno-based detection methods for RS. The review begins by introducing RS, highlighting its destructive potential and the need for point-of-care detection techniques. Subsequently, it explores traditional detection methods and their limitations, emphasizing the need for innovative approaches. The main focus of this review is on immuno-based detection methods and it discusses recent advancements in serological detection techniques. Furthermore, the review sheds light on the challenges and prospects of immuno-based detection of RS. It emphasizes the importance of developing rapid, field-deployable assays that can be used by farmers and researchers alike. In conclusion, this review provides valuable insights into the recent advances in immuno-based detection methods for RS.
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Affiliation(s)
- Shalini Bhatt
- P P Savani University, Surat 394125, Gujarat, India; Defence Institute of Bio-Energy Research (DIBER), DRDO, Nainital, Haldwani 263139, Uttarakhand, India.
| | - Neha Faridi
- Defence Institute of Bio-Energy Research (DIBER), DRDO, Nainital, Haldwani 263139, Uttarakhand, India
| | - S Merwyn P Raj
- Defence Institute of Bio-Energy Research (DIBER), DRDO, Nainital, Haldwani 263139, Uttarakhand, India
| | - Ankur Agarwal
- Defence Institute of Bio-Energy Research (DIBER), DRDO, Nainital, Haldwani 263139, Uttarakhand, India
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2
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Barbat B, Douzi B, Ball G, Tribout M, El Karkouri K, Kellenberger C, Voulhoux R. Insights into dynamics and gating properties of T2SS secretins. SCIENCE ADVANCES 2023; 9:eadg6996. [PMID: 37792935 PMCID: PMC10550240 DOI: 10.1126/sciadv.adg6996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 09/05/2023] [Indexed: 10/06/2023]
Abstract
Secretins are outer membrane (OM) channels found in various bacterial nanomachines that secrete or assemble large extracellular structures. High-resolution 3D structures of type 2 secretion system (T2SS) secretins revealed bimodular channels with a C-module, holding a conserved central gate and an optional top gate, followed by an N-module for which multiple structural organizations have been proposed. Here, we perform a structure-driven in vivo study of the XcpD secretin, which validates one of the organizations of the N-module whose flexibility enables alternative conformations. We also show the existence of the central gate in vivo and its required flexibility, which is key for substrate passage and watertightness control. Last, functional, genomic, and phylogenetic analyses indicate that the optional top gate provides a gain of watertightness. Our data illustrate how the gating properties of T2SS secretins allow these large channels to overcome the duality between the necessity of preserving the OM impermeability while simultaneously promoting the secretion of large, folded effectors.
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Affiliation(s)
- Brice Barbat
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
| | - Badreddine Douzi
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
- Université de Lorraine, INRAE, DynAMic, Nancy, F-54000 France
| | - Geneviève Ball
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
| | - Mathilde Tribout
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
| | | | | | - Romé Voulhoux
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
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3
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Tassinari M, Rudzite M, Filloux A, Low HH. Assembly mechanism of a Tad secretion system secretin-pilotin complex. Nat Commun 2023; 14:5643. [PMID: 37704603 PMCID: PMC10499894 DOI: 10.1038/s41467-023-41200-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 08/25/2023] [Indexed: 09/15/2023] Open
Abstract
The bacterial Tight adherence Secretion System (TadSS) assembles surface pili that drive cell adherence, biofilm formation and bacterial predation. The structure and mechanism of the TadSS is mostly unknown. This includes characterisation of the outer membrane secretin through which the pilus is channelled and recruitment of its pilotin. Here we investigate RcpA and TadD lipoprotein from Pseudomonas aeruginosa. Light microscopy reveals RcpA colocalising with TadD in P. aeruginosa and when heterologously expressed in Escherichia coli. We use cryogenic electron microscopy to determine how RcpA and TadD assemble a secretin channel with C13 and C14 symmetries. Despite low sequence homology, we show that TadD shares a similar fold to the type 4 pilus system pilotin PilF. We establish that the C-terminal four residues of RcpA bind TadD - an interaction essential for secretin formation. The binding mechanism between RcpA and TadD appears distinct from known secretin-pilotin pairings in other secretion systems.
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Affiliation(s)
- Matteo Tassinari
- Department of Infectious Disease, Imperial College, London, SW7 2AZ, UK
- Human Technopole, Milan, Italy
| | - Marta Rudzite
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Alain Filloux
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Harry H Low
- Department of Infectious Disease, Imperial College, London, SW7 2AZ, UK.
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4
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Yu Z, Wu Y, Chen M, Huo T, Zheng W, Ludtke SJ, Shi X, Wang Z. Membrane translocation process revealed by in situ structures of type II secretion system secretins. Nat Commun 2023; 14:4025. [PMID: 37419909 PMCID: PMC10329019 DOI: 10.1038/s41467-023-39583-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 06/20/2023] [Indexed: 07/09/2023] Open
Abstract
The GspD secretin is the outer membrane channel of the bacterial type II secretion system (T2SS) which secrets diverse toxins that cause severe diseases such as diarrhea and cholera. GspD needs to translocate from the inner to the outer membrane to exert its function, and this process is an essential step for T2SS to assemble. Here, we investigate two types of secretins discovered so far in Escherichia coli, GspDα, and GspDβ. By electron cryotomography subtomogram averaging, we determine in situ structures of key intermediate states of GspDα and GspDβ in the translocation process, with resolution ranging from 9 Å to 19 Å. In our results, GspDα and GspDβ present entirely different membrane interaction patterns and ways of transitioning the peptidoglycan layer. From this, we hypothesize two distinct models for the membrane translocation of GspDα and GspDβ, providing a comprehensive perspective on the inner to outer membrane biogenesis of T2SS secretins.
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Affiliation(s)
- Zhili Yu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yaoming Wu
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China
| | - Muyuan Chen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, 94025, USA
| | - Tong Huo
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Wei Zheng
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China
| | - Steven J Ludtke
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
- Cryo Electron Microscopy and Tomography Core, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xiaodong Shi
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China.
| | - Zhao Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
- Cryo Electron Microscopy and Tomography Core, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
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5
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Barbat B, Douzi B, Voulhoux R. Structural lessons on bacterial secretins. Biochimie 2023; 205:110-116. [PMID: 36096236 DOI: 10.1016/j.biochi.2022.08.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/26/2022] [Accepted: 08/31/2022] [Indexed: 11/30/2022]
Abstract
To exchange and communicate with their surroundings, bacteria have evolved multiple active and passive mechanisms for trans-envelope transport. Among the pore-forming complexes found in the outer membrane of Gram-negative bacteria, secretins are distinctive homo-oligomeric channels dedicated to the active translocation of voluminous structures such as folded proteins, assembled fibers, virus particles or DNA. Members of the bacterial secretin family share a common cylinder-shaped structure with a gated pore-forming part inserted in the outer membrane, and a periplasmic channel connected to the inner membrane components of the corresponding nanomachine. In this mini-review, we will present what recently determined 3D structures have told us about the mechanisms of translocation through secretins of large substrates to the bacterial surface or in the extracellular milieu.
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Affiliation(s)
- Brice Barbat
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, 13009, Marseille, France
| | | | - Romé Voulhoux
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, 13009, Marseille, France.
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6
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Yu Z, Wu Y, Chen M, Huo T, Zheng W, Ludtke SJ, Shi X, Wang Z. In situ structures of secretins from bacterial type II secretion system reveal their membrane interactions and translocation process. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.10.523476. [PMID: 36711656 PMCID: PMC9882097 DOI: 10.1101/2023.01.10.523476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The GspD secretin is the outer membrane channel of the bacterial type II secretion system (T2SS) which secrets diverse effector proteins or toxins that cause severe diseases such as diarrhea and cholera. GspD needs to translocate from the inner to the outer membrane to exert its function, and this process is an essential step for T2SS to assemble. Here, we investigate two types of secretins discovered so far in Escherichia coli , GspD α and GspD β , respectively. By electron cryotomography subtomogram averaging, we determine in situ structures of all the key intermediate states of GspD α and GspD β in the translocation process, with resolution ranging from 9 Å to 19 Å. In our results, GspD α and GspD β present entirely different membrane interaction patterns and ways of going across the peptidoglycan layer. We propose two distinct models for the membrane translocation of GspD α and GspD β , providing a comprehensive perspective on the inner to outer membrane biogenesis of T2SS secretins.
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7
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Scaffolding Protein GspB/OutB Facilitates Assembly of the Dickeya dadantii Type 2 Secretion System by Anchoring the Outer Membrane Secretin Pore to the Inner Membrane and to the Peptidoglycan Cell Wall. mBio 2022; 13:e0025322. [PMID: 35546537 PMCID: PMC9239104 DOI: 10.1128/mbio.00253-22] [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] [Indexed: 11/24/2022] Open
Abstract
The phytopathogenic proteobacterium Dickeya dadantii secretes an array of plant cell wall-degrading enzymes and other virulence factors via the type 2 secretion system (T2SS). T2SSs are widespread among important plant, animal, and human bacterial pathogens. This multiprotein complex spans the double membrane cell envelope and secretes fully folded proteins through a large outer membrane pore formed by 15 subunits of the secretin GspD. Secretins are also found in the type 3 secretion system and the type 4 pili. Usually, specialized lipoproteins termed pilotins assist the targeting and assembly of secretins into the outer membrane. Here, we show that in D. dadantii, the pilotin acts in concert with the scaffolding protein GspB. Deletion of gspB profoundly impacts secretin assembly, pectinase secretion, and virulence. Structural studies reveal that GspB possesses a conserved periplasmic homology region domain that interacts directly with the N-terminal secretin domain. Site-specific photo-cross-linking unravels molecular details of the GspB-GspD complex in vivo. We show that GspB facilitates outer membrane targeting and assembly of the secretin pores and anchors them to the inner membrane while the C-terminal extension of GspB provides a scaffold for the secretin channel in the peptidoglycan cell wall. Phylogenetic analysis shows that in other bacteria, GspB homologs vary in length and domain composition and act in concert with either a cognate ATPase GspA or the pilotin GspS.
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Liu B, Chan H, Bauda E, Contreras-Martel C, Bellard L, Villard AM, Mas C, Neumann E, Fenel D, Favier A, Serrano M, Henriques AO, Rodrigues CDA, Morlot C. Structural insights into ring-building motif domains involved in bacterial sporulation. J Struct Biol 2021; 214:107813. [PMID: 34808342 DOI: 10.1016/j.jsb.2021.107813] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/29/2021] [Accepted: 11/15/2021] [Indexed: 02/06/2023]
Abstract
Components of specialized secretion systems, which span the inner and outer membranes in Gram-negative bacteria, include ring-forming proteins whose oligomerization was proposed to be promoted by domains called RBM for "Ring-Building Motifs". During spore formation in Gram-positive bacteria, a transport system called the SpoIIIA-SpoIIQ complex also assembles in the double membrane that surrounds the forespore following its endocytosis by the mother cell. The presence of RBM domains in some of the SpoIIIA proteins led to the hypothesis that they would assemble into rings connecting the two membranes and form a conduit between the mother cell and forespore. Among them, SpoIIIAG forms homo-oligomeric rings in vitro but the oligomerization of other RBM-containing SpoIIIA proteins, including SpoIIIAH, remains to be demonstrated. In this work, we identified RBM domains in the YhcN/YlaJ family of proteins that are not related to the SpoIIIA-SpoIIQ complex. We solved the crystal structure of YhcN from Bacillus subtilis, which confirmed the presence of a RBM fold, flanked by additional secondary structures. As the protein did not show any oligomerization ability in vitro, we investigated the structural determinants of ring formation in SpoIIIAG, SpoIIIAH and YhcN. We showed that in vitro, the conserved core of RBM domains alone is not sufficient for oligomerization while the β-barrel forming region in SpoIIIAG forms rings on its own. This work suggests that some RBMs might indeed participate in the assembly of homomeric rings but others might have evolved toward other functions.
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Affiliation(s)
- Bowen Liu
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Helena Chan
- The ithree institute, University of Technology Sydney, 2007 Ultimo, NSW, Australia
| | - Elda Bauda
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | | | - Laure Bellard
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | | | - Caroline Mas
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | | | - Daphna Fenel
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Adrien Favier
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Monica Serrano
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Adriano O Henriques
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Oeiras, Portugal
| | | | - Cecile Morlot
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France.
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9
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Yaman D, Averhoff B. Functional dissection of structural regions of the Thermus thermophilus competence protein PilW: Implication in secretin complex stability, natural transformation and pilus functions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183666. [PMID: 34143999 DOI: 10.1016/j.bbamem.2021.183666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/29/2021] [Accepted: 06/01/2021] [Indexed: 01/13/2023]
Abstract
Uptake of DNA from the environment into the bacterial cytoplasm is mediated by a macromolecular transport machinery that is similar in structure and function to type IV pili (T4P) and, indeed, DNA translocator and T4P share common components. One is the secretin PilQ which is assembled into homopolymeric complexes forming highly dynamic outer membrane (OM) channels mediating pilus extrusion and DNA uptake. How PilQ interacts with the motor is still enigmatic. Here, we have used biochemical and genetic techniques to study the interaction of PilQ with PilW, a unique protein which is essential for natural transformation and T4P extrusion of T. thermophilus. PilQ and PilW form high molecular mass complexes in the OM of T. thermophilus. When pilW was deleted, PilQ complexes were no longer observed but only PilQ monomers, accompanied by a loss of DNA uptake as well as a loss of T4P and twitching motility. Piliation of a ΔpilT2/ΔpilW double mutant suggests that PilW is important for stable assembly of PilQ complexes. To analyze the role of different regions of PilW, partial deletions (pilW∆2-40, pilW∆50-150, pilW∆163-216 and pilW∆216-292) were generated and the effect on DNA uptake, PilQ complex formation and T4P functions such as twitching motility, biofilm formation and cell-cell interaction was studied. These studies revealed that a central disordered region in PilW is required for pilus dynamics. We propose that PilW is part of a protein network that connects the transport ATPase to drive different functions of the DNA translocator and T4P.
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Affiliation(s)
- Deniz Yaman
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Beate Averhoff
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany.
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10
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Sun H, Liu M, Fan F, Li Z, Fan Y, Zhang J, Huang Y, Li Z, Li J, Xu J, Kan B. The Type II Secretory System Mediates Phage Infection in Vibrio cholerae. Front Cell Infect Microbiol 2021; 11:662344. [PMID: 33968805 PMCID: PMC8101328 DOI: 10.3389/fcimb.2021.662344] [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: 02/01/2021] [Accepted: 03/29/2021] [Indexed: 11/25/2022] Open
Abstract
Attachment and specific binding to the receptor on the host cell surface is the first step in the process of bacteriophage infection. The lytic phage VP2 is used in phage subtyping of the Vibrio cholerae biotype El Tor of the O1 serogroup; however, its infection mechanism is poorly understood. In this study, we aimed to identify its receptor on V. cholerae. The outer membrane protein EpsD in the type II secretory system (T2SS) was found to be related to VP2-specific adsorption to V. cholerae, and the T2SS inner membrane protein EpsM had a role in successful VP2 infection, although it was not related to adsorption of VP2. The tail fiber protein gp20 of VP2 directly interacts with EpsD. Therefore, we found that in V. cholerae, in addition to the roles of the T2SS as the transport apparatus of cholera toxin secretion and filamentous phage release, the T2SS is also used as the receptor for phage infection and probably as the channel for phage DNA injection. Our study expands the understanding of the roles of the T2SS in bacteria.
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Affiliation(s)
- Huihui Sun
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,National Institute of Environment Health, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Ming Liu
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Fenxia Fan
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Zhe Li
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yufeng Fan
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jingyun Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yuanming Huang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Zhenpeng Li
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jie Li
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jialiang Xu
- School of Light Industry, Beijing Technology and Business University, Beijing, China
| | - Biao Kan
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
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11
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Grishin A, Voth K, Gagarinova A, Cygler M. Structural biology of the invasion arsenal of Gram-negative bacterial pathogens. FEBS J 2021; 289:1385-1427. [PMID: 33650300 DOI: 10.1111/febs.15794] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 02/11/2021] [Accepted: 02/26/2021] [Indexed: 12/20/2022]
Abstract
In the last several years, there has been a tremendous progress in the understanding of host-pathogen interactions and the mechanisms by which bacterial pathogens modulate behavior of the host cell. Pathogens use secretion systems to inject a set of proteins, called effectors, into the cytosol of the host cell. These effectors are secreted in a highly regulated, temporal manner and interact with host proteins to modify a multitude of cellular processes. The number of effectors varies between pathogens from ~ 30 to as many as ~ 350. The functional redundancy of effectors encoded by each pathogen makes it difficult to determine the cellular effects or function of individual effectors, since their individual knockouts frequently produce no easily detectable phenotypes. Structural biology of effector proteins and their interactions with host proteins, in conjunction with cell biology approaches, has provided invaluable information about the cellular function of effectors and underlying molecular mechanisms of their modes of action. Many bacterial effectors are functionally equivalent to host proteins while being structurally divergent from them. Other effector proteins display new, previously unobserved functionalities. Here, we summarize the contribution of the structural characterization of effectors and effector-host protein complexes to our understanding of host subversion mechanisms used by the most commonly investigated Gram-negative bacterial pathogens. We describe in some detail the enzymatic activities discovered among effector proteins and how they affect various cellular processes.
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Affiliation(s)
- Andrey Grishin
- Department of Biochemistry, Microbiology, & Immunology, University of Saskatchewan, Saskatoon, Canada
| | - Kevin Voth
- Department of Biochemistry, Microbiology, & Immunology, University of Saskatchewan, Saskatoon, Canada
| | - Alla Gagarinova
- Department of Biochemistry, Microbiology, & Immunology, University of Saskatchewan, Saskatoon, Canada
| | - Miroslaw Cygler
- Department of Biochemistry, Microbiology, & Immunology, University of Saskatchewan, Saskatoon, Canada
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12
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Lebov JF, Bohannan BJM. Msh Pilus Mutations Increase the Ability of a Free-Living Bacterium to Colonize a Piscine Host. Genes (Basel) 2021; 12:genes12020127. [PMID: 33498301 PMCID: PMC7909257 DOI: 10.3390/genes12020127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/12/2021] [Accepted: 01/18/2021] [Indexed: 02/07/2023] Open
Abstract
Symbioses between animals and bacteria are ubiquitous. To better understand these relationships, it is essential to unravel how bacteria evolve to colonize hosts. Previously, we serially passaged the free-living bacterium, Shewanella oneidensis, through the digestive tracts of germ-free larval zebrafish (Danio rerio) to uncover the evolutionary changes involved in the initiation of a novel symbiosis with a vertebrate host. After 20 passages, we discovered an adaptive missense mutation in the mshL gene of the msh pilus operon, which improved host colonization, increased swimming motility, and reduced surface adhesion. In the present study, we determined that this mutation was a loss-of-function mutation and found that it improved zebrafish colonization by augmenting S. oneidensis representation in the water column outside larvae through a reduced association with environmental surfaces. Additionally, we found that strains containing the mshL mutation were able to immigrate into host digestive tracts at higher rates per capita. However, mutant and evolved strains exhibited no evidence of a competitive advantage after colonizing hosts. Our results demonstrate that bacterial behaviors outside the host can play a dominant role in facilitating the onset of novel host associations.
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Affiliation(s)
- Jarrett F. Lebov
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403-5289, USA;
- Correspondence:
| | - Brendan J. M. Bohannan
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403-5289, USA;
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13
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Naskar S, Hohl M, Tassinari M, Low HH. The structure and mechanism of the bacterial type II secretion system. Mol Microbiol 2020; 115:412-424. [PMID: 33283907 DOI: 10.1111/mmi.14664] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/03/2020] [Indexed: 12/17/2022]
Abstract
The type II secretion system (T2SS) is a multi-protein complex used by many bacteria to move substrates across their cell membrane. Substrates released into the environment serve as local and long-range effectors that promote nutrient acquisition, biofilm formation, and pathogenicity. In both animals and plants, the T2SS is increasingly recognized as a key driver of virulence. The T2SS spans the bacterial cell envelope and extrudes substrates through an outer membrane secretin channel using a pseudopilus. An inner membrane assembly platform and a cytoplasmic motor controls pseudopilus assembly. This microreview focuses on the structure and mechanism of the T2SS. Advances in cryo-electron microscopy are enabling increasingly elaborate sub-complexes to be resolved. However, key questions remain regarding the mechanism of pseudopilus extension and retraction, and how this is coupled with the choreography of the substrate moving through the secretion system. The T2SS is part of an ancient type IV filament superfamily that may have been present within the last universal common ancestor (LUCA). Overall, mechanistic principles that underlie T2SS function have implication for other closely related systems such as the type IV and tight adherence pilus systems.
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Affiliation(s)
- Souvik Naskar
- Department of Infectious Disease, Imperial College, London, UK
| | - Michael Hohl
- Department of Infectious Disease, Imperial College, London, UK
| | | | - Harry H Low
- Department of Infectious Disease, Imperial College, London, UK
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14
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Weaver SJ, Ortega DR, Sazinsky MH, Dalia TN, Dalia AB, Jensen GJ. CryoEM structure of the type IVa pilus secretin required for natural competence in Vibrio cholerae. Nat Commun 2020; 11:5080. [PMID: 33033258 PMCID: PMC7545093 DOI: 10.1038/s41467-020-18866-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023] Open
Abstract
Natural transformation is the process by which bacteria take up genetic material from their environment and integrate it into their genome by homologous recombination. It represents one mode of horizontal gene transfer and contributes to the spread of traits like antibiotic resistance. In Vibrio cholerae, a type IVa pilus (T4aP) is thought to facilitate natural transformation by extending from the cell surface, binding to exogenous DNA, and retracting to thread this DNA through the outer membrane secretin, PilQ. Here, we use a functional tagged allele of VcPilQ purified from native V. cholerae cells to determine the cryoEM structure of the VcPilQ secretin in amphipol to ~2.7 Å. We use bioinformatics to examine the domain architecture and gene neighborhood of T4aP secretins in Proteobacteria in comparison with VcPilQ. This structure highlights differences in the architecture of the T4aP secretin from the type II and type III secretion system secretins. Based on our cryoEM structure, we design a series of mutants to reversibly regulate VcPilQ gate dynamics. These experiments support the idea of VcPilQ as a potential druggable target and provide insight into the channel that DNA likely traverses to promote the spread of antibiotic resistance via horizontal gene transfer by natural transformation.
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Affiliation(s)
- Sara J Weaver
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA, 91125, USA.,Howard Hughes Medical Institute, David Geffen School of Medicine, Departments of Biological Chemistry and Physiology, University of California Los Angeles, 615 Charles E Young Drive South, Los Angeles, CA, 90095, USA
| | - Davi R Ortega
- Division of Biology and Biological Engineering and Howard Hughes Medical Institute, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA, 91125, USA
| | - Matthew H Sazinsky
- Department of Chemistry, Pomona College, 333N. College Way, Claremont, CA, 91711, USA
| | - Triana N Dalia
- Department of Biology, Indiana University, 107S. Indiana Avenue, Bloomington, IN, 47405, USA
| | - Ankur B Dalia
- Department of Biology, Indiana University, 107S. Indiana Avenue, Bloomington, IN, 47405, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering and Howard Hughes Medical Institute, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA, 91125, USA.
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15
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Majewski DD, Okon M, Heinkel F, Robb CS, Vuckovic M, McIntosh LP, Strynadka NCJ. Characterization of the Pilotin-Secretin Complex from the Salmonella enterica Type III Secretion System Using Hybrid Structural Methods. Structure 2020; 29:125-138.e5. [PMID: 32877645 DOI: 10.1016/j.str.2020.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/21/2020] [Accepted: 08/11/2020] [Indexed: 12/01/2022]
Abstract
The type III secretion system (T3SS) is a multi-membrane-spanning protein channel used by Gram-negative pathogenic bacteria to secrete effectors directly into the host cell cytoplasm. In the many species reliant on the T3SS for pathogenicity, proper assembly of the outer membrane secretin pore depends on a diverse family of lipoproteins called pilotins. We present structural and biochemical data on the Salmonella enterica pilotin InvH and the S domain of its cognate secretin InvG. Characterization of InvH by X-ray crystallography revealed a dimerized, α-helical pilotin. Size-exclusion-coupled multi-angle light scattering and small-angle X-ray scattering provide supporting evidence for the formation of an InvH homodimer in solution. Structures of the InvH-InvG heterodimeric complex determined by X-ray crystallography and NMR spectroscopy indicate a predominantly hydrophobic interface. Knowledge of the interaction between InvH and InvG brings us closer to understanding the mechanisms by which pilotins assemble the secretin pore.
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Affiliation(s)
- Dorothy D Majewski
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Mark Okon
- Michael Smith Laboratories, Department of Biochemistry and Molecular Biology, and Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
| | - Florian Heinkel
- Michael Smith Laboratories, Department of Biochemistry and Molecular Biology, and Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
| | - Craig S Robb
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Marija Vuckovic
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Lawrence P McIntosh
- Michael Smith Laboratories, Department of Biochemistry and Molecular Biology, and Department of Chemistry, University of British Columbia, Vancouver, BC, Canada.
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada.
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16
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Zhang M, Kang J, Wu B, Qin Y, Huang L, Zhao L, Mao L, Wang S, Yan Q. Comparative transcriptome and phenotype analysis revealed the role and mechanism of ompR in the virulence of fish pathogenic Aeromonas hydrophila. Microbiologyopen 2020; 9:e1041. [PMID: 32282134 PMCID: PMC7349151 DOI: 10.1002/mbo3.1041] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 12/16/2022] Open
Abstract
Aeromonas hydrophila B11 strain was isolated from diseased Anguilla japonica, which had caused severe gill ulcers in farmed eel, causing huge economic losses. EnvZ‐OmpR is a model two‐component system in the bacteria and is widely used in the research of signal transduction and gene transcription regulation. In this study, the ompR of A. hydrophila B11 strain was first silenced by RNAi technology. The role of ompR in the pathogenicity of A. hydrophila B11 was investigated by analyzing both the bacterial comparative transcriptome and phenotype. The qRT‐PCR results showed that the expression of ompR in the ompR‐RNAi strain decreased by 97% compared with the wild‐type strain. The virulence test showed that after inhibition of the ompR expression, the LD50 of A. hydrophila B11 decreased by an order of magnitude, suggesting that ompR is involved in the regulation of bacterial virulence. Comparative transcriptome analysis showed that the expression of ompR can directly regulate the expression of several important virulence‐related genes, such as the bacterial type II secretion system; moreover, ompR expression also regulates the expression of multiple genes related to bacterial chemotaxis, motility, adhesion, and biofilm formation. Further studies on the phenotype of A. hydrophila B11 and ompR‐RNAi also confirmed that the downregulation of ompR expression can decrease bacterial chemotaxis, adhesion, and biofilm formation.
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Affiliation(s)
- Mengmeng Zhang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Jianping Kang
- Fujian Fisheries Technology Extension Center, Fuzhou, China
| | - Bin Wu
- Fujian Fisheries Technology Extension Center, Fuzhou, China
| | - Yingxue Qin
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China.,Fujian Province Key Laboratory of Special Aquatic Formula Feed, Fujian Tianma Science and Technology Group Co., Ltd., Fuqing, China
| | - Lixing Huang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Lingmin Zhao
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Leilei Mao
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Suyun Wang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Qingpi Yan
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
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17
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Higuchi K, Yabuki T, Ito M, Kigawa T. Cold shock proteins improve
E. coli
cell‐free synthesis in terms of soluble yields of aggregation‐prone proteins. Biotechnol Bioeng 2020; 117:1628-1639. [DOI: 10.1002/bit.27326] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/05/2020] [Accepted: 03/08/2020] [Indexed: 11/10/2022]
Affiliation(s)
- Kae Higuchi
- Laboratory for Cellular Structural BiologyRIKEN Center for Biosystems Dynamics Research Yokohama Kanagawa Japan
| | - Takashi Yabuki
- Laboratory for Cellular Structural BiologyRIKEN Center for Biosystems Dynamics Research Yokohama Kanagawa Japan
- SI Innovation Center, Taiyo Nippon Sanso Corporation Tama‐shi Tokyo Japan
| | - Masahiro Ito
- Laboratory for Cellular Structural BiologyRIKEN Center for Biosystems Dynamics Research Yokohama Kanagawa Japan
| | - Takanori Kigawa
- Laboratory for Cellular Structural BiologyRIKEN Center for Biosystems Dynamics Research Yokohama Kanagawa Japan
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18
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Silva YRDO, Contreras-Martel C, Macheboeuf P, Dessen A. Bacterial secretins: Mechanisms of assembly and membrane targeting. Protein Sci 2020; 29:893-904. [PMID: 32020694 DOI: 10.1002/pro.3835] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/25/2020] [Accepted: 01/28/2020] [Indexed: 12/20/2022]
Abstract
Secretion systems are employed by bacteria to transport macromolecules across membranes without compromising their integrities. Processes including virulence, colonization, and motility are highly dependent on the secretion of effector molecules toward the immediate cellular environment, and in some cases, into the host cytoplasm. In Type II and Type III secretion systems, as well as in Type IV pili, homomultimeric complexes known as secretins form large pores in the outer bacterial membrane, and the localization and assembly of such 1 MDa molecules often relies on pilotins or accessory proteins. Significant progress has been made toward understanding details of interactions between secretins and their partner proteins using approaches ranging from bacterial genetics to cryo electron microscopy. This review provides an overview of the mode of action of pilotins and accessory proteins for T2SS, T3SS, and T4PS secretins, highlighting recent near-atomic resolution cryo-EM secretin complex structures and underlining the importance of these interactions for secretin functionality.
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Affiliation(s)
- Yuri Rafael de Oliveira Silva
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, São Paulo, Brazil.,Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Carlos Contreras-Martel
- Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Pauline Macheboeuf
- Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Andréa Dessen
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, São Paulo, Brazil.,Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
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19
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Ghosal D, Kim KW, Zheng H, Kaplan M, Truchan HK, Lopez AE, McIntire IE, Vogel JP, Cianciotto NP, Jensen GJ. In vivo structure of the Legionella type II secretion system by electron cryotomography. Nat Microbiol 2019; 4:2101-2108. [PMID: 31754273 PMCID: PMC6879910 DOI: 10.1038/s41564-019-0603-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022]
Abstract
The type II secretion system (T2SS) is a multiprotein envelope-spanning assembly that translocates a wide range of virulence factors, enzymes and effectors through the outer membrane of many Gram-negative bacteria1-3. Here, using electron cryotomography and subtomogram averaging methods, we reveal the in vivo structure of an intact T2SS imaged within the human pathogen Legionella pneumophila. Although the T2SS has only limited sequence and component homology with the evolutionarily related type IV pilus (T4P) system4,5, we show that their overall architectures are remarkably similar. Despite similarities, there are also differences, including, for example, that the T2SS-ATPase complex is usually present but disengaged from the inner membrane, the T2SS has a much longer periplasmic vestibule and it has a short-lived flexible pseudopilus. Placing atomic models of the components into our electron cryotomography map produced a complete architectural model of the intact T2SS that provides insights into the structure and function of its components, its position within the cell envelope and the interactions between its different subcomplexes.
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Affiliation(s)
- Debnath Ghosal
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Ki Woo Kim
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- School of Ecology and Environmental System, Kyungpook National University, Sangju, Korea
| | - Huaixin Zheng
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Department of Immunology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou City, Henan Province, China
| | - Mohammed Kaplan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Hilary K Truchan
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Alberto E Lopez
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Ian E McIntire
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Joseph P Vogel
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA
| | - Nicholas P Cianciotto
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
- Howard Hughes Medical Institute, Pasadena, CA, USA.
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