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Mom J, Chouikha I, Valette O, Pieulle L, Pelicic V. Systematic functional analysis of the Com pilus in Streptococcus sanguinis: a minimalistic type 4 filament dedicated to DNA uptake in monoderm bacteria. mBio 2024; 15:e0266723. [PMID: 38095871 PMCID: PMC10790768 DOI: 10.1128/mbio.02667-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/07/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE Type 4 filaments (T4F) are nanomachines ubiquitous in prokaryotes, centered on filamentous polymers of type 4 pilins. T4F are exceptionally versatile and widespread virulence factors in bacterial pathogens. The mechanisms of filament assembly and the many functions they facilitate remain poorly understood because of the complexity of T4F machineries. This hinders the development of anti-T4F drugs. The significance of our research lies in characterizing the simplest known T4F-the Com pilus that mediates DNA uptake in competent monoderm bacteria-and showing that four protein components universally conserved in T4F are sufficient for filament assembly. The Com pilus becomes a model for elucidating the mechanisms of T4F assembly.
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Affiliation(s)
- Jeremy Mom
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Iman Chouikha
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Odile Valette
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Laetitia Pieulle
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Vladimir Pelicic
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
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2
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Douzi B. Surface Plasmon Resonance: A Sensitive Tool to Study Protein-Protein Interactions. Methods Mol Biol 2024; 2715:363-382. [PMID: 37930540 DOI: 10.1007/978-1-0716-3445-5_23] [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] [Indexed: 11/07/2023]
Abstract
Surface plasmon resonance (SPR) is one of the most commonly used techniques to study protein-protein interactions. The main advantage of SPR is the ability of measuring binding affinities and association/dissociation kinetics of complexes in real time, in a label-free environment, and using relatively small quantities of materials. The method is based on the immobilization of one of the binding partners, called the "ligand," on a dedicated sensor surface. Immobilization is followed by the injection of the other partner, called the "analyte," over the surface containing the ligand. The binding is monitored by following changes in the refractive index of the medium close to the sensor surface upon injection of the analyte. During the last 15 years, SPR has been intensively used in the study of bacterial secretion systems due to its ability of detecting highly dynamic complexes, which are difficult to investigate by other techniques. This chapter will guide users in setting up SPR experiments in order to identify protein complexes and to assess their binding affinity and/or kinetics. It will include detailed protocols for (i) immobilization of proteins with the amine coupling capture method, (ii) analyte-binding analysis, (iii) affinity/kinetics measurements, and (iv) data analysis.
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3
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Anger R, Pieulle L, Shahin M, Valette O, Le Guenno H, Kosta A, Pelicic V, Fronzes R. Structure of a heteropolymeric type 4 pilus from a monoderm bacterium. Nat Commun 2023; 14:7143. [PMID: 37932265 PMCID: PMC10628169 DOI: 10.1038/s41467-023-42872-5] [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: 06/15/2023] [Accepted: 10/24/2023] [Indexed: 11/08/2023] Open
Abstract
Type 4 pili (T4P) are important virulence factors, which belong to a superfamily of nanomachines ubiquitous in prokaryotes, called type 4 filaments (T4F). T4F are defined as helical polymers of type 4 pilins. Recent advances in cryo-electron microscopy (cryo-EM) led to structures of several T4F, revealing that the long N-terminal α-helix (α1) - the trademark of pilins - packs in the centre of the filaments to form a hydrophobic core. In diderm bacteria - all available bacterial T4F structures are from diderm species - a portion of α1 is melted (unfolded). Here we report that this architecture is conserved in phylogenetically distant monoderm species by determining the structure of Streptococcus sanguinis T4P. Our 3.7 Å resolution cryo-EM structure of S. sanguinis heteropolymeric T4P and the resulting full atomic model including all minor pilins highlight universal features of bacterial T4F and have widespread implications in understanding T4F biology.
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Affiliation(s)
- Robin Anger
- Institut Européen de Chimie et Biologie, Université de Bordeaux-CNRS (UMR 5234), Pessac, France
| | - Laetitia Pieulle
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS (UMR 7283), Marseille, France
| | - Meriam Shahin
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Odile Valette
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS (UMR 7283), Marseille, France
| | - Hugo Le Guenno
- Plateforme de Microscopie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, Marseille, France
| | - Artemis Kosta
- Plateforme de Microscopie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, Marseille, France
| | - Vladimir Pelicic
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS (UMR 7283), Marseille, France.
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK.
| | - Rémi Fronzes
- Institut Européen de Chimie et Biologie, Université de Bordeaux-CNRS (UMR 5234), Pessac, France.
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4
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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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5
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Li Y, Santos-Moreno J, Francetic O. The periplasmic coiled coil formed by the assembly platform proteins PulL and PulM is critical for function of the Klebsiella type II secretion system. Res Microbiol 2023; 174:104075. [PMID: 37141929 DOI: 10.1016/j.resmic.2023.104075] [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: 09/28/2022] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/06/2023]
Abstract
Bacteria use type II secretion systems (T2SS) to secrete to their surface folded proteins that confer diverse functions, from nutrient acquisition to virulence. In the Klebsiella species, T2SS-mediated secretion of pullulanase (PulA) requires assembly of a dynamic filament called the endopilus. The inner membrane assembly platform (AP) subcomplex is essential for endopilus assembly and PulA secretion. AP components PulL and PulM interact with each other through their C-terminal globular domains and transmembrane segments. Here, we investigated the roles of their periplasmic helices, predicted to form a coiled coil, in assembly and function of the PulL-PulM complex. PulL and PulM variants lacking these periplasmic helices were defective for interaction in the bacterial two-hybrid (BACTH) assay. Their functions in PulA secretion and assembly of PulG subunits into endopilus filaments were strongly reduced. Interestingly, deleting the cytoplasmic peptide of PulM nearly abolished the function of variant PulMΔN and its interaction with PulG, but not with PulL, in the BACTH assay. Nevertheless, PulL was specifically proteolyzed in the presence of the PulMΔN variant, suggesting that PulM N-terminal peptide stabilizes PulL in the cytoplasm. We discuss the implications of these results for the T2S endopilus and type IV pilus assembly mechanisms.
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Affiliation(s)
- Yuanyuan Li
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Biochemistry of Macromolecular Interactions Unit, F-75015 Paris, France.
| | - Javier Santos-Moreno
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Biochemistry of Macromolecular Interactions Unit, F-75015 Paris, France.
| | - Olivera Francetic
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Biochemistry of Macromolecular Interactions Unit, F-75015 Paris, France.
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6
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Qi L, Shi M, Zhu FC, Lian CA, He LS. Genomic evidence for the first symbiotic Deferribacterota, a novel gut symbiont from the deep-sea hydrothermal vent shrimp Rimicaris kairei. Front Microbiol 2023; 14:1179935. [PMID: 37455748 PMCID: PMC10344455 DOI: 10.3389/fmicb.2023.1179935] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 06/08/2023] [Indexed: 07/18/2023] Open
Abstract
The genus Rimicaris is the dominant organism living in hydrothermal vents. However, little research has been done on the functions of their intestinal flora. Here, we investigated the potential functions of Deferribacterota, which is dominant in the intestine of Rimicaris kairei from the Central Indian Ridge. In total, six metagenome-assembled genomes (MAGs) of Deferribacterota were obtained using the metagenomic approach. The six Deferribacterota MAGs (Def-MAGs) were clustered into a new branch in the phylogenetic tree. The six Def-MAGs were further classified into three species, including one new order and two new genera, based on the results of phylogenetic analysis, relative evolutionary divergence (RED), average nucleotide identity (ANI), average amino acid identity (AAI) and DNA-DNA hybridization (DDH) values. The results of the energy metabolism study showed that these bacteria can use a variety of carbon sources, such as glycogen, sucrose, salicin, arbutin, glucose, cellobiose, and maltose. These bacteria have a type II secretion system and effector proteins that can transport some intracellular toxins to the extracellular compartment and a type V CRISPR-Cas system that can defend against various invasions. In addition, cofactors such as biotin, riboflavin, flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD) synthesized by R. kairei gut Deferribacterota may also assist their host in surviving under extreme conditions. Taken together, the potential function of Deferribacterota in the hydrothermal R. kairei gut suggests its long-term coevolution with the host.
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Affiliation(s)
- Li Qi
- Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Mengke Shi
- Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Fang-Chao Zhu
- Key Laboratory of Tropical Marine Ecosystem and Bioresource, Fourth Institute of Oceanography, Ministry of Natural Resources, Beihai, China
| | - Chun-Ang Lian
- Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China
| | - Li-Sheng He
- Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China
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7
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Shen Y, Gao S, Fan Q, Zuo J, Wang Y, Yi L, Wang Y. New antibacterial targets: Regulation of quorum sensing and secretory systems in zoonotic bacteria. Microbiol Res 2023; 274:127436. [PMID: 37343493 DOI: 10.1016/j.micres.2023.127436] [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: 03/17/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/23/2023]
Abstract
Quorum sensing (QS) is a communication mechanism that controls bacterial communication and can influence the transcriptional expression of multiple genes through one or more signaling molecules, thereby coordinating the population response of multiple bacterial pathogens. Secretion systems (SS) play an equally important role in bacterial information exchange, relying on the secretory systems to secrete proteins that act as virulence factors to promote adhesion to host cells. Eight highly efficient SS have been described, all of which are involved in the secretion or transfer of virulence factors, and the effector proteins they secrete play a key role in the virulence and pathogenicity of bacteria. It has been shown that many bacterial SS are directly or indirectly regulated by QS and thus influence bacterial virulence and antibiotic resistance. This review describes the relationship between QS and SS of several common zoonotic pathogenic bacteria and outlines the molecular mechanisms of how QS systems regulate SS, to provide a theoretical basis for the study of bacterial pathogenicity and the development of novel antibacterial drugs.
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Affiliation(s)
- Yamin Shen
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China
| | - Shuji Gao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China
| | - Qingying Fan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China
| | - Jing Zuo
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China
| | - Yuxin Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China
| | - Li Yi
- Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China; College of Life Science, Luoyang Normal University, Luoyang, China.
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Henan Engineering Research Center of Livestock and Poultry Emerging Disease Detection and Control, Luoyang, China.
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8
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Shaliutina-Loginova A, Francetic O, Doležal P. Bacterial Type II Secretion System and Its Mitochondrial Counterpart. mBio 2023; 14:e0314522. [PMID: 36971557 PMCID: PMC10128026 DOI: 10.1128/mbio.03145-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Over the billions of years that bacteria have been around, they have evolved several sophisticated protein secretion nanomachines to deliver toxins, hydrolytic enzymes, and effector proteins into their environments. Of these, the type II secretion system (T2SS) is used by Gram-negative bacteria to export a wide range of folded proteins from the periplasm across the outer membrane.
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9
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Pelicic V. Mechanism of assembly of type 4 filaments: everything you always wanted to know (but were afraid to ask). MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36947586 DOI: 10.1099/mic.0.001311] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Type 4 filaments (T4F) are a superfamily of filamentous nanomachines - virtually ubiquitous in prokaryotes and functionally versatile - of which type 4 pili (T4P) are the defining member. T4F are polymers of type 4 pilins, assembled by conserved multi-protein machineries. They have long been an important topic for research because they are key virulence factors in numerous bacterial pathogens. Our poor understanding of the molecular mechanisms of T4F assembly is a serious hindrance to the design of anti-T4F therapeutics. This review attempts to shed light on the fundamental mechanistic principles at play in T4F assembly by focusing on similarities rather than differences between several (mostly bacterial) T4F. This holistic approach, complemented by the revolutionary ability of artificial intelligence to predict protein structures, led to an intriguing mechanistic model of T4F assembly.
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Affiliation(s)
- Vladimir Pelicic
- Laboratoire de Chimie Bactérienne, UMR 7283 CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, Marseille, France
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10
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Konishi K, Yasutake Y, Muramatsu S, Murata S, Yoshida K, Ishiya K, Aburatani S, Sakasegawa SI, Tamura T. Disruption of SMC-related genes promotes recombinant cholesterol esterase production in Burkholderia stabilis. Appl Microbiol Biotechnol 2022; 106:8093-8110. [PMID: 36399168 DOI: 10.1007/s00253-022-12277-3] [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: 07/15/2022] [Revised: 11/01/2022] [Accepted: 11/04/2022] [Indexed: 11/19/2022]
Abstract
Burkholderia stabilis strain FERMP-21014 secretes cholesterol esterase (BsChe), which is used in clinical settings to determine serum cholesterol levels. Previously, we constructed an expression plasmid with an endogenous constitutive promoter to enable the production of recombinant BsChe. In this study, we obtained one mutant strain with 13.1-fold higher BsChe activity than the wild type, using N-methyl-N'-nitro-N-nitrosoguanidine as a mutagen. DNA-sequencing analysis revealed that the strain had lost chromosome 3 (∆Chr3), suggesting that the genes hindering BsChe production may be encoded on Chr3. We also identified common mutations in the functionally unknown BSFP_068720/30 genes in the top 10 active strains generated during transposon mutagenesis. As BSFP_068720/30/40 comprised an operon on Chr3, we created the BSFP_068720/30/40 disruption mutant and confirmed that each disruption mutant containing the expression plasmid exhibited ~ 16.1-fold higher BsChe activity than the wild type. Quantitative PCR showed that each disruption mutant and ΔChr3 had a ~ 9.4-fold higher plasmid copy number than the wild type. Structural prediction models indicate that BSFP_068730/40 is structurally homologous to the structural maintenance of chromosomes (SMC) protein MukBE, which is responsible for chromosome segregation during cell division. Conversely, BSFP_068720/30/40 disruption did not lead to a Chr3 drop-out. These results imply that BSFP_068720/30/40 is not a SMC protein but is involved in destabilizing foreign plasmids to prevent the influx of genetic information from the environment. In conclusion, the disruption of BSFP_068720/30/40 improved plasmid stability and copy number, resulting in exceptionally high BsChe production. KEY POINTS: • Disruption of BSFP_068720/30/40 enabled mass production of Burkholderia Che/Lip. • BSFP_068730/40 is an SMC protein homolog not involved in chromosome retention. • BSFP_068720/30/40 is likely responsible for the exclusion of exogenous plasmids.
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Affiliation(s)
- Kenji Konishi
- Asahi Kasei Pharma Corporation, Shizuoka, 410-2321, Japan.,Laboratory of Molecular Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Yoshiaki Yasutake
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan.,Computational Bio Big-Data Open Innovation Laboratory (CBBD-OIL), AIST, Tokyo, 169-8555, Japan
| | | | - Satomi Murata
- Asahi Kasei Pharma Corporation, Shizuoka, 410-2321, Japan
| | - Keitaro Yoshida
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan
| | - Koji Ishiya
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan
| | - Sachiyo Aburatani
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan
| | | | - Tomohiro Tamura
- Laboratory of Molecular Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan. .,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan.
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Papadopoulos A, Busch M, Reiners J, Hachani E, Baeumers M, Berger J, Schmitt L, Jaeger KE, Kovacic F, Smits SHJ, Kedrov A. The periplasmic chaperone Skp prevents misfolding of the secretory lipase A from Pseudomonas aeruginosa. Front Mol Biosci 2022; 9:1026724. [DOI: 10.3389/fmolb.2022.1026724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a wide-spread opportunistic human pathogen and a high-risk factor for immunodeficient people and patients with cystic fibrosis. The extracellular lipase A belongs to the virulence factors of P. aeruginosa. Prior to the secretion, the lipase undergoes folding and activation by the periplasmic foldase LipH. At this stage, the enzyme is highly prone to aggregation in mild and high salt concentrations typical for the sputum of cystic fibrosis patients. Here, we demonstrate that the periplasmic chaperone Skp of P. aeruginosa efficiently prevents misfolding of the lipase A in vitro. In vivo experiments in P. aeruginosa show that the lipase secretion is nearly abolished in absence of the endogenous Skp. Small-angle X-ray scattering elucidates the trimeric architecture of P. aeruginosa Skp and identifies two primary conformations of the chaperone, a compact and a widely open. We describe two binding modes of Skp to the lipase, with affinities of 20 nM and 2 μM, which correspond to 1:1 and 1:2 stoichiometry of the lipase:Skp complex. Two Skp trimers are required to stabilize the lipase via the apolar interactions, which are not affected by elevated salt concentrations. We propose that Skp is a crucial chaperone along the lipase maturation and secretion pathway that ensures stabilization and carry-over of the client to LipH.
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12
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Dade CM, Douzi B, Cambillau C, Ball G, Voulhoux R, Forest KT. The crystal structure of CbpD clarifies substrate-specificity motifs in chitin-active lytic polysaccharide monooxygenases. Acta Crystallogr D Struct Biol 2022; 78:1064-1078. [PMID: 35916229 PMCID: PMC9344471 DOI: 10.1107/s2059798322007033] [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: 04/16/2022] [Accepted: 07/08/2022] [Indexed: 11/23/2022] Open
Abstract
Pseudomonas aeruginosa secretes diverse proteins via its type 2 secretion system, including a 39 kDa chitin-binding protein, CbpD. CbpD has recently been shown to be a lytic polysaccharide monooxygenase active on chitin and to contribute substantially to virulence. To date, no structure of this virulence factor has been reported. Its first two domains are homologous to those found in the crystal structure of Vibrio cholerae GbpA, while the third domain is homologous to the NMR structure of the CBM73 domain of Cellvibrio japonicus CjLPMO10A. Here, the 3.0 Å resolution crystal structure of CbpD solved by molecular replacement is reported, which required ab initio models of each CbpD domain generated by the artificial intelligence deep-learning structure-prediction algorithm RoseTTAFold. The structure of CbpD confirms some previously reported substrate-specificity motifs among LPMOAA10s, while challenging the predictive power of others. Additionally, the structure of CbpD shows that post-translational modifications occur on the chitin-binding surface. Moreover, the structure raises interesting possibilities about how type 2 secretion-system substrates may interact with the secretion machinery and demonstrates the utility of new artificial intelligence protein structure-prediction algorithms in making challenging structural targets tractable.
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Affiliation(s)
- Christopher M. Dade
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Badreddine Douzi
- Aix-Marseille University, CNRS, IMM, LCB, Marseille, France
- Aix-Marseille University, CNRS, AFMB, Marseille, France
| | | | - Genevieve Ball
- Aix-Marseille University, CNRS, IMM, LCB, Marseille, France
| | - Romé Voulhoux
- Aix-Marseille University, CNRS, IMM, LCB, Marseille, France
| | - Katrina T. Forest
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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13
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InvL, an Invasin-Like Adhesin, Is a Type II Secretion System Substrate Required for Acinetobacter baumannii Uropathogenesis. mBio 2022; 13:e0025822. [PMID: 35638734 PMCID: PMC9245377 DOI: 10.1128/mbio.00258-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Acinetobacter baumannii is an opportunistic pathogen of growing concern, as isolates are commonly multidrug resistant. While A. baumannii is most frequently associated with pulmonary infections, a significant proportion of clinical isolates come from urinary sources, highlighting its uropathogenic potential. The type II secretion system (T2SS) of commonly used model Acinetobacter strains is important for virulence in various animal models, but the potential role of the T2SS in urinary tract infection (UTI) remains unknown. Here, we used a catheter-associated UTI (CAUTI) model to demonstrate that a modern urinary isolate, UPAB1, requires the T2SS for full virulence. A proteomic screen to identify putative UPAB1 T2SS effectors revealed an uncharacterized lipoprotein with structural similarity to the intimin-invasin family, which serve as type V secretion system (T5SS) adhesins required for the pathogenesis of several bacteria. This protein, designated InvL, lacked the β-barrel domain associated with T5SSs but was confirmed to require the T2SS for both surface localization and secretion. This makes InvL the first identified T2SS effector belonging to the intimin-invasin family. InvL was confirmed to be an adhesin, as the protein bound to extracellular matrix components and mediated adhesion to urinary tract cell lines in vitro. Additionally, the invL mutant was attenuated in the CAUTI model, indicating a role in Acinetobacter uropathogenesis. Finally, bioinformatic analyses revealed that InvL is present in nearly all clinical isolates belonging to international clone 2, a lineage of significant clinical importance. In all, we conclude that the T2SS substrate InvL is an adhesin required for A. baumannii uropathogenesis. IMPORTANCE While pathogenic Acinetobacter can cause various infections, we recently found that 20% of clinical isolates come from urinary sources. Despite the clinical relevance of Acinetobacter as a uropathogen, few virulence factors involved in urinary tract colonization have been defined. Here, we identify a novel type II secretion system effector, InvL, which is required for full uropathogenesis by a modern urinary isolate. Although InvL has predicted structural similarity to the intimin-invasin family of autotransporter adhesins, InvL is predicted to be anchored to the membrane as a lipoprotein. Similar to other invasin homologs, however, we demonstrate that InvL is a bona fide adhesin capable of binding extracellular matrix components and mediating adhesion to urinary tract cell lines. In all, this work establishes InvL as an adhesin important for Acinetobacter's urinary tract virulence and represents the first report of a type II secretion system effector belonging to the intimin-invasin family.
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Pseudomonas aeruginosa Secretes the Oxylipin Autoinducer Synthases OdsA and OdsB via the Xcp Type 2 Secretion System. J Bacteriol 2022; 204:e0011422. [PMID: 35658521 DOI: 10.1128/jb.00114-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The oxylipin-dependent quorum-sensing system (ODS) of Pseudomonas aeruginosa relies on the production and sensing of two extracellular oxylipins, 10S-hydroxy-(8E)-octadecenoic acid (10-HOME) and 7S,10S-dihydroxy-(8E)-octadecenoic acid (7,10-DiHOME). Here, we implemented a genetic screen of P. aeruginosa strain PAO1 aimed to identify genes required for 10-HOME and 7,10-DiHOME production. Among the 14 genes identified, four encoded previously known components of the ODS and 10 encoded parts of the Xcp type II secretion system (T2SS). We subsequently created a clean xcpQ deletion mutant, which encodes the necessary outer membrane component of Xcp, and found it recapitulated the impaired functionality of the T2SS transposon mutants. Further studies showed that the ΔxcpQ mutant was unable to secrete the oxylipin synthase enzymes across the outer membrane. Specifically, immunoblotting for OdsA, which is responsible for the generation of 10-HOME from oleic acid, detected the enzyme in supernatants from wild-type PAO1 but not ΔxcpQ cultures. Likewise, chromatography of supernatants found that 10-HOME was not in supernatants collected from the ΔxcpQ mutant. Accordingly, diol synthase activity was increased in the periplasm of ΔxcpQ mutant consistent with a stoppage in its transport. Importantly, after exposure of the ΔxcpQ mutant to exogenous 10-HOME and 7,10-DiHOME, the ODS effector genes become active; thus, the sensing component of the ODS does not involve the T2SS. Finally, we observed that Xcp contributed to robust in vitro and in vivo biofilm formation in oleic acid availability- and ODS-dependent manner. Thus, T2SS-mediated transport of the oxylipin synthase enzymes to outside the bacterial cell is required for ODS functionality. IMPORTANCE We previously showed that the ODS of P. aeruginosa produces and responds to oxylipins derived from host oleic acid by enhancing biofilm formation and virulence. Here, we developed a genetic screen strategy to explore the molecular basis for oxylipins synthesis and detection. Unexpectedly, we found that the ODS autoinducer synthases cross the outer membrane using the Xcp type 2 secretion system (T2SS) of P. aeruginosa, and so the biosynthesis of oxylipins occurs extracellularly. T2SS promoted biofilm formation in the presence of oleic acid as a result of ODS activation. Our results identify two new T2SS secreted proteins in P. aeruginosa and reveal a new way by which this important opportunistic pathogen interacts with the host environment.
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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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Filloux A. Bacterial protein secretion systems: Game of types. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35536734 DOI: 10.1099/mic.0.001193] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Protein trafficking across the bacterial envelope is a process that contributes to the organisation and integrity of the cell. It is the foundation for establishing contact and exchange between the environment and the cytosol. It helps cells to communicate with one another, whether they establish symbiotic or competitive behaviours. It is instrumental for pathogenesis and for bacteria to subvert the host immune response. Understanding the formation of envelope conduits and the manifold strategies employed for moving macromolecules across these channels is a fascinating playground. The diversity of the nanomachines involved in this process logically resulted in an attempt to classify them, which is where the protein secretion system types emerged. As our knowledge grew, so did the number of types, and their rightful nomenclature started to be questioned. While this may seem a semantic or philosophical issue, it also reflects scientific rigour when it comes to assimilating findings into textbooks and science history. Here I give an overview on bacterial protein secretion systems, their history, their nomenclature and why it can be misleading for newcomers in the field. Note that I do not try to suggest a new nomenclature. Instead, I explore the reasons why naming could have escaped our control and I try to reiterate basic concepts that underlie protein trafficking cross membranes.
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Affiliation(s)
- Alain Filloux
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
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The molecular basis of FimT-mediated DNA uptake during bacterial natural transformation. Nat Commun 2022; 13:1065. [PMID: 35246533 PMCID: PMC8897410 DOI: 10.1038/s41467-022-28690-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 02/08/2022] [Indexed: 01/05/2023] Open
Abstract
Naturally competent bacteria encode sophisticated protein machinery for the uptake and translocation of exogenous DNA into the cell. If this DNA is integrated into the bacterial genome, the bacterium is said to be naturally transformed. Most competent bacterial species utilise type IV pili for the initial DNA uptake step. These proteinaceous cell-surface structures are composed of thousands of pilus subunits (pilins), designated as major or minor according to their relative abundance in the pilus. Here, we show that the minor pilin FimT plays an important role in the natural transformation of Legionella pneumophila. We use NMR spectroscopy, in vitro DNA binding assays and in vivo transformation assays to understand the molecular basis of FimT's role in this process. FimT binds to DNA via an electropositive patch, rich in arginines, several of which are well-conserved and located in a conformationally flexible C-terminal tail. FimT orthologues from other Gammaproteobacteria share the ability to bind to DNA. Our results suggest that FimT plays an important role in DNA uptake in a wide range of competent species.
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Structural interactions define assembly adapter function of a type II secretion system pseudopilin. Structure 2021; 29:1116-1127.e8. [PMID: 34139172 DOI: 10.1016/j.str.2021.05.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/15/2021] [Accepted: 05/28/2021] [Indexed: 01/13/2023]
Abstract
The type IV filament superfamily comprises widespread membrane-associated polymers in prokaryotes. The type II secretion system (T2SS), a virulence pathway in many pathogens, belongs to this superfamily. A knowledge gap in understanding of the T2SS is the molecular role of a small "pseudopilin" protein. Using multiple biophysical techniques, we have deciphered how this missing component of the Xcp T2SS architecture is structurally integrated, and thereby unlocked its function. We demonstrate that low-abundance XcpH is the adapter that bridges a trimeric initiating tip complex, XcpIJK, with a periplasmic filament of XcpG subunits. Each pseudopilin protein caps an XcpG protofilament in an overall pseudopilus compatible with dimensions of the periplasm and the outer membrane-spanning secretin through which substrates pass. Unexpectedly, to fulfill its adapter function, the XcpH N-terminal helix must be unwound, a property shared with XcpG subunits. We provide an experimentally validated three-dimensional structural model of a complete type IV filament.
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Pseudomonas aeruginosa elastase (LasB) as a therapeutic target. Drug Discov Today 2021; 26:2108-2123. [PMID: 33676022 DOI: 10.1016/j.drudis.2021.02.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/03/2021] [Accepted: 02/17/2021] [Indexed: 02/08/2023]
Abstract
Why is P. aeruginosa LasB elastase an attractive target for antivirulence therapy and what is the state-of-the art in LasB inhibitor design and development?
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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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21
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Zhang Y, Wang S, Jia Z. In Situ Proteolysis Condition-Induced Crystallization of the XcpVWX Complex in Different Lattices. Int J Mol Sci 2020; 21:ijms21010308. [PMID: 31906428 PMCID: PMC6981927 DOI: 10.3390/ijms21010308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 12/28/2019] [Accepted: 12/29/2019] [Indexed: 12/13/2022] Open
Abstract
Although prevalent in the determination of protein structures; crystallography always has the bottleneck of obtaining high-quality protein crystals for characterizing a wide range of proteins; especially large protein complexes. Stable fragments or domains of proteins are more readily to crystallize; which prompts the use of in situ proteolysis to remove flexible or unstable structures for improving crystallization and crystal quality. In this work; we investigated the effects of in situ proteolysis by chymotrypsin on the crystallization of the XcpVWX complex from the Type II secretion system of Pseudomonas aeruginosa. Different proteolysis conditions were found to result in two distinct lattices in the same crystallization solution. With a shorter chymotrypsin digestion at a lower concentration; the crystals exhibited a P3 hexagonal lattice that accommodates three complex molecules in one asymmetric unit. By contrast; a longer digestion with chymotrypsin of a 10-fold higher concentration facilitated the formation of a compact P212121 orthorhombic lattice with only one complex molecule in each asymmetric unit. The molecules in the hexagonal lattice have shown high atomic displacement parameter values compared with the ones in the orthorhombic lattice. Taken together; our results clearly demonstrate that different proteolysis conditions can result in the generation of distinct lattices in the same crystallization solution; which can be exploited in order to obtain different crystal forms of a better quality
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Affiliation(s)
- Yichen Zhang
- Department of Biomedical and Molecular Sciences, Queen’s University, 18 Stuart Street, Kingston, ON K7L 3N6, Canada;
| | - Shu Wang
- College of Chemistry, Beijing Normal University, 19 Xinjiekou Outer Street, Beijing 100875, China;
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen’s University, 18 Stuart Street, Kingston, ON K7L 3N6, Canada;
- Correspondence: ; Tel.: +86-1-613-533-6277
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22
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Jacobsen T, Bardiaux B, Francetic O, Izadi-Pruneyre N, Nilges M. Structure and function of minor pilins of type IV pili. Med Microbiol Immunol 2019; 209:301-308. [PMID: 31784891 PMCID: PMC7248040 DOI: 10.1007/s00430-019-00642-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 11/14/2019] [Indexed: 02/06/2023]
Abstract
Type IV pili are versatile and highly flexible fibers formed on the surface of many Gram-negative and Gram-positive bacteria. Virulence and infection rate of several pathogenic bacteria, such as Neisseria meningitidis and Pseudomonas aeruginosa, are strongly dependent on the presence of pili as they facilitate the adhesion of the bacteria to the host cell. Disruption of the interactions between the pili and the host cells by targeting proteins involved in this interaction could, therefore, be a treatment strategy. A type IV pilus is primarily composed of multiple copies of protein subunits called major pilins. Additional proteins, called minor pilins, are present in lower abundance, but are essential for the assembly of the pilus or for its specific functions. One class of minor pilins is required to initiate the formation of pili, and may form a complex similar to that identified in the related type II secretion system. Other, species-specific minor pilins in the type IV pilus system have been shown to promote additional functions such as DNA binding, aggregation and adherence. Here, we will review the structure and the function of the minor pilins from type IV pili.
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Affiliation(s)
- Theis Jacobsen
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, C3BI, Institut Pasteur, CNRS UMR3528, CNRS USR3756, Paris, France.,Sorbonne Université, Complexité du Vivant, 75005, Paris, France
| | - Benjamin Bardiaux
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, C3BI, Institut Pasteur, CNRS UMR3528, CNRS USR3756, Paris, France
| | - Olivera Francetic
- Biochemistry of Macromolecular Interactions Unit, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR3528, Paris, France
| | - Nadia Izadi-Pruneyre
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, C3BI, Institut Pasteur, CNRS UMR3528, CNRS USR3756, Paris, France
| | - Michael Nilges
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, C3BI, Institut Pasteur, CNRS UMR3528, CNRS USR3756, Paris, France.
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23
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López-Jácome LE, Garza-Ramos G, Hernández-Durán M, Franco-Cendejas R, Loarca D, Romero-Martínez D, Nguyen PTD, Maeda T, González-Pedrajo B, Díaz-Guerrero M, Sánchez-Reyes JL, Díaz-Ramírez D, García-Contreras R. AiiM Lactonase Strongly Reduces Quorum Sensing Controlled Virulence Factors in Clinical Strains of Pseudomonas aeruginosa Isolated From Burned Patients. Front Microbiol 2019; 10:2657. [PMID: 31798568 PMCID: PMC6868103 DOI: 10.3389/fmicb.2019.02657] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/31/2019] [Indexed: 01/25/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic bacterium associated with healthcare infections in intensive care units (ICUs), ventilator-associated pneumonia (VAP), surgical site infections, and burns. This bacterium causes 75% of death in burned patients, since it can develop a persistent biofilm associated with infections, express several virulence factors, and antibiotic-resistance mechanisms. Some of these virulence factors are proteases such as elastase and alkaline protease, or toxic metabolites such as pyocyanin and is one of the few microorganisms able to produce cyanide, which inhibits the cytochrome oxidase of host cells. These virulence factors are controlled by quorum sensing (QS). In this work, 30 P. aeruginosa clinical strains isolated from burned patients from a tertiary hospital in Mexico City were studied. Antibiotic susceptibility tests were done, and virulence factors (elastase, alkaline protease, HCN, and pyocyanin) were determined in presence of an N-acylhomoserine lactonase, AiiM able to hydrolyze a wide range of acyl homoserine lactones. The treatment reduced significantly the activities of elastase and alkaline protease, and the production of pyocyanin and HCN in all producer strains but not the secretion of toxins through the type III secretion system. Our work suggests that AiiM treatment may be an effective therapy to combat P. aeruginosa infection in burn patients.
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Affiliation(s)
- Luis Esaú López-Jácome
- Laboratorio de Bacteriología, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Laboratorio de Infectología, Centro Nacional de Investigación y Atención de Quemados, Instituto Nacional de Rehabilitación, Mexico City, Mexico
| | - Georgina Garza-Ramos
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Melissa Hernández-Durán
- Laboratorio de Infectología, Centro Nacional de Investigación y Atención de Quemados, Instituto Nacional de Rehabilitación, Mexico City, Mexico
| | - Rafael Franco-Cendejas
- Laboratorio de Infectología, Centro Nacional de Investigación y Atención de Quemados, Instituto Nacional de Rehabilitación, Mexico City, Mexico
| | - Daniel Loarca
- Laboratorio de Bacteriología, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Daniel Romero-Martínez
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Phuong Thi Dong Nguyen
- Department of Biological Functions Engineering, Gradute School of Life Sciences and System Engineering, Kyushu Institute of Technology, Kitakyushu, Japan
| | - Toshinari Maeda
- Department of Biological Functions Engineering, Gradute School of Life Sciences and System Engineering, Kyushu Institute of Technology, Kitakyushu, Japan
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Miguel Díaz-Guerrero
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Jorge Luis Sánchez-Reyes
- Laboratorio de Bacteriología, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Dánae Díaz-Ramírez
- Laboratorio de Bacteriología, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Rodolfo García-Contreras
- Laboratorio de Bacteriología, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
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24
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Sana TG, Lomas R, Gimenez MR, Laubier A, Soscia C, Chauvet C, Conesa A, Voulhoux R, Ize B, Bleves S. Differential Modulation of Quorum Sensing Signaling through QslA in Pseudomonas aeruginosa Strains PAO1 and PA14. J Bacteriol 2019; 201:e00362-19. [PMID: 31405911 PMCID: PMC6779463 DOI: 10.1128/jb.00362-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/06/2019] [Indexed: 11/20/2022] Open
Abstract
Two clinical isolates of the opportunist pathogen Pseudomonas aeruginosa named PAO1 and PA14 are commonly studied in research laboratories. Despite the isolates being closely related, PA14 exhibits increased virulence compared to that of PAO1 in various models. To determine which players are responsible for the hypervirulence phenotype of the PA14 strain, we elected a transcriptomic approach through RNA sequencing. We found 2,029 genes that are differentially expressed between the two strains, including several genes that are involved with or regulated by quorum sensing (QS), known to control most of the virulence factors in P. aeruginosa Among them, we chose to focus our study on QslA, an antiactivator of QS whose expression was barely detectable in the PA14 strain according our data. We hypothesized that lack of expression of qslA in PA14 could be responsible for higher QS expression in the PA14 strain, possibly explaining its hypervirulence phenotype. After confirming that QslA protein was highly produced in PAO1 but not in the PA14 strain, we obtained evidence showing that a PAO1 deletion strain of qslA has faster QS gene expression kinetics than PA14. Moreover, known virulence factors activated by QS, such as (i) pyocyanin production, (ii) H2-T6SS (type VI secretion system) gene expression, and (iii) Xcp-T2SS (type II secretion system) machinery production and secretion, were all lower in PAO1 than in PA14, due to higher qslA expression. However, biofilm formation and cytotoxicity toward macrophages, although increased in PA14 compared to PAO1, were independent of QslA control. Together, our findings implicated differential qslA expression as a major determinant of virulence factor expression in P. aeruginosa strains PAO1 and PA14.IMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen responsible for acute nosocomial infections and chronic pulmonary infections. P. aeruginosa strain PA14 is known to be hypervirulent in different hosts. Despite several studies in the field, the underlining molecular mechanisms sustaining this phenotype remain enigmatic. Here we provide evidence that the PA14 strain has faster quorum sensing (QS) kinetics than the PAO1 strain, due to the lack of QslA expression, an antiactivator of QS. QS is a major regulator of virulence factors in P. aeruginosa; therefore, we propose that the hypervirulent phenotype of the PA14 strain is, at least partially, due to the lack of QslA expression. This mechanism could be of great importance, as it could be conserved among other P. aeruginosa isolates.
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Affiliation(s)
- T G Sana
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires-UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille University and CNRS, Marseille, France
| | - R Lomas
- Genomics of Gene Expression Laboratory, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - M R Gimenez
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires-UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille University and CNRS, Marseille, France
| | - A Laubier
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires-UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille University and CNRS, Marseille, France
| | - C Soscia
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires-UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille University and CNRS, Marseille, France
| | - C Chauvet
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires-UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille University and CNRS, Marseille, France
| | - A Conesa
- Microbiology and Cell Science, IFAS, Genetics Insitute, University of Florida, Gainesville, Florida, USA
| | - R Voulhoux
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires-UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille University and CNRS, Marseille, France
| | - B Ize
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires-UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille University and CNRS, Marseille, France
| | - S Bleves
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires-UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille University and CNRS, Marseille, France
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25
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Verma N, Dollinger P, Kovacic F, Jaeger KE, Gohlke H. The Membrane-Integrated Steric Chaperone Lif Facilitates Active Site Opening of Pseudomonas aeruginosa Lipase A. J Comput Chem 2019; 41:500-512. [PMID: 31618459 DOI: 10.1002/jcc.26085] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/22/2019] [Accepted: 09/25/2019] [Indexed: 12/19/2022]
Abstract
Lipases are essential and widely used biocatalysts. Hence, the production of lipases requires a detailed understanding of the molecular mechanism of its folding and secretion. Lipase A from Pseudomonas aeruginosa, PaLipA, constitutes a prominent example that has additional relevance because of its role as a virulence factor in many diseases. PaLipA requires the assistance of a membrane-integrated steric chaperone, the lipase-specific foldase Lif, to achieve its enzymatically active state. However, the molecular mechanism of how Lif activates its cognate lipase has remained elusive. Here, we show by molecular dynamics simulations at the atomistic level and potential of mean force computations that Lif catalyzes the activation process of PaLipA by structurally stabilizing an intermediate PaLipA conformation, particularly a β-sheet in the region of residues 17-30, such that the opening of PaLipA's lid domain is facilitated. This opening allows substrate access to PaLipA's catalytic site. A surprising and so far not fully understood aspect of our study is that the open state of PaLipA is unstable compared to the closed one according to our computational and in vitro biochemical results. We thus speculate that further interactions of PaLipA with the Xcp secretion machinery and/or components of the extracellular matrix contribute to the remaining activity of secreted PaLipA. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Neha Verma
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitätstr. 1, 40225, Düsseldorf, Germany
| | - Peter Dollinger
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich GmbH, 52426, Jülich, Germany
| | - Filip Kovacic
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich GmbH, 52426, Jülich, Germany
| | - Karl-Erich Jaeger
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich GmbH, 52426, Jülich, Germany.,Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52426, Jülich, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitätstr. 1, 40225, Düsseldorf, Germany.,John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC) and Institute for Complex Systems-Structural Biochemistry (ICS-6), Forschungszentrum Jülich GmbH, 52426, Jülich, Germany
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26
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Abstract
The type II secretion system (T2SS) delivers toxins and a range of hydrolytic enzymes, including proteases, lipases, and carbohydrate-active enzymes, to the cell surface or extracellular space of Gram-negative bacteria. Its contribution to survival of both extracellular and intracellular pathogens as well as environmental species of proteobacteria is evident. This dynamic, multicomponent machinery spans the entire cell envelope and consists of a cytoplasmic ATPase, several inner membrane proteins, a periplasmic pseudopilus, and a secretin pore embedded in the outer membrane. Despite the trans-envelope configuration of the T2S nanomachine, proteins to be secreted engage with the system first once they enter the periplasmic compartment via the Sec or TAT export system. Thus, the T2SS is specifically dedicated to their outer membrane translocation. The many sequence and structural similarities between the T2SS and type IV pili suggest a common origin and argue for a pilus-mediated mechanism of secretion. This minireview describes the structures, functions, and interactions of the individual T2SS components and the general architecture of the assembled T2SS machinery and briefly summarizes the transport and function of a growing list of T2SS exoproteins. Recent advances in cryo-electron microscopy, which have led to an increased understanding of the structure-function relationship of the secretin channel and the pseudopilus, are emphasized.
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27
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White RC, Cianciotto NP. Assessing the impact, genomics and evolution of type II secretion across a large, medically important genus: the Legionella type II secretion paradigm. Microb Genom 2019; 5. [PMID: 31166887 PMCID: PMC6617341 DOI: 10.1099/mgen.0.000273] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The type II secretion system (T2SS) plays a major role in promoting bacterial survival in the environment and in human hosts. One of the best characterized T2SS is that of Legionella pneumophila, the agent of Legionnaires’ disease. Secreting at least 25 proteins, including degradative enzymes, eukaryotic-like proteins and novel effectors, this T2SS contributes to the ability of L. pneumophila to grow at low temperatures, infect amoebal and macrophage hosts, damage lung tissue, evade the immune system, and undergo sliding motility. The genes encoding the T2SS are conserved across the genus Legionella, which includes 62 species and >30 pathogens in addition to L. pneumophila. The vast majority of effectors associated with L. pneumophila are shared by a large number of Legionella species, hinting at a critical role for them in the ecology of Legionella as a whole. However, no other species has the same repertoire as L. pneumophila, with, as a general rule, phylogenetically more closely related species sharing similar sets of effectors. T2SS effectors that are involved in infection of a eukaryotic host(s) are more prevalent throughout Legionella, indicating that they are under stronger selective pressure. The Legionella T2SS apparatus is closest to that of Aquicella (another parasite of amoebae), and a significant number of L. pneumophila effectors have their closest homologues in Aquicella. Thus, the T2SS of L. pneumophila probably originated within the order Legionellales, with some of its effectors having arisen within that Aquicella-like progenitor, while other effectors derived from the amoebal host, mimiviruses, fungi and less closely related bacteria.
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Affiliation(s)
- Richard C White
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Nicholas P Cianciotto
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
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28
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Luna Rico A, Zheng W, Petiot N, Egelman EH, Francetic O. Functional reconstitution of the type IVa pilus assembly system from enterohaemorrhagic Escherichia coli. Mol Microbiol 2019; 111:732-749. [PMID: 30561149 DOI: 10.1111/mmi.14188] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/04/2018] [Indexed: 12/17/2022]
Abstract
Type 4a pili (T4aP) are long, thin and dynamic fibres displayed on the surface of diverse bacteria promoting adherence, motility and transport functions. Genomes of many Enterobacteriaceae contain conserved gene clusters encoding putative T4aP assembly systems. However, their expression has been observed only in few strains including Enterohaemorrhagic Escherichia coli (EHEC) and their inducers remain unknown. Here we used EHEC genomic DNA as a template to amplify and assemble an artificial operon composed of four gene clusters encoding 13 pilus assembly proteins. Controlled expressions of this operon in nonpathogenic E. coli strains led to efficient assembly of T4aP composed of the major pilin PpdD, as shown by shearing assays and immunofluorescence microscopy. When compared with PpdD pili assembled in a heterologous Klebsiella T2SS type 2 secretion system (T2SS) by using cryo-electron microscopy (cryoEM), these pili showed indistinguishable helical parameters, emphasizing that major pilins are the principal determinants of the fibre structure. Bacterial two-hybrid analysis identified several interactions of PpdD with T4aP assembly proteins, and with components of the T2SS that allow for heterologous fibre assembly. These studies lay ground for further characterization of the T4aP structure, function and biogenesis in enterobacteria.
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Affiliation(s)
- Areli Luna Rico
- Biochemistry of Macromolecular Interactions Unit, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR3528, 28 rue du Dr Roux, Paris, 75724, France.,Structural Bioinformatics Unit and NMR of Biomolecules Unit, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR3528, 28 rue du Dr Roux, Paris, 75724, France
| | - Weili Zheng
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Nathalie Petiot
- Biochemistry of Macromolecular Interactions Unit, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR3528, 28 rue du Dr Roux, Paris, 75724, France
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Olivera Francetic
- Biochemistry of Macromolecular Interactions Unit, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR3528, 28 rue du Dr Roux, Paris, 75724, France
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29
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Zhang Y, Faucher F, Zhang W, Wang S, Neville N, Poole K, Zheng J, Jia Z. Structure-guided disruption of the pseudopilus tip complex inhibits the Type II secretion in Pseudomonas aeruginosa. PLoS Pathog 2018; 14:e1007343. [PMID: 30346996 PMCID: PMC6211770 DOI: 10.1371/journal.ppat.1007343] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/01/2018] [Accepted: 09/19/2018] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa utilizes the Type II secretion system (T2SS) to translocate a wide range of large, structured protein virulence factors through the periplasm to the extracellular environment for infection. In the T2SS, five pseudopilins assemble into the pseudopilus that acts as a piston to extrude exoproteins out of cells. Through structure determination of the pseudopilin complexes of XcpVWX and XcpVW and function analysis, we have confirmed that two minor pseudopilins, XcpV and XcpW, constitute a core complex indispensable to the pseudopilus tip. The absence of either XcpV or -W resulted in the non-functional T2SS. Our small-angle X-ray scattering experiment for the first time revealed the architecture of the entire pseudopilus tip and established the working model. Based on the interaction interface of complexes, we have developed inhibitory peptides. The structure-based peptides not only disrupted of the XcpVW core complex and the entire pseudopilus tip in vitro but also inhibited the T2SS in vivo. More importantly, these peptides effectively reduced the virulence of P. aeruginosa towards Caenorhabditis elegans. The Type II secretion system has been characterized as an important virulence factor translocation machine that secrets various toxic proteins from the periplasm into the extracellular milieu used by a wide spectrum of Gram-negative bacteria. Through the characterization of the structure of the pseudopilus tip complex by protein crystallography and small-angle X-ray scattering, we have identified a critical interaction interface in the core binary complex formed by two minor pseudopilins, XcpV and–W, in Pseudomonas aeruginosa. Based on the interaction interface, two inhibitory peptides were developed, which showed potency of disrupting the entire pseudopilus tip complex and further inhibited the Type II secretion system. When applied to Caenorhabditis elegans, these peptides prevent the killing of worms by the P. aeruginosa. Our work has represented the first successful research on the inhibition of the Type II secretion system based on the structure of the pseudopilus tip complex.
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Affiliation(s)
- Yichen Zhang
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Frédérick Faucher
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Wenwen Zhang
- Faculty of Health Sciences, University of Macau, Macau, China
| | - Shu Wang
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Nolan Neville
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Keith Poole
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Jun Zheng
- Faculty of Health Sciences, University of Macau, Macau, China
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
- * E-mail:
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30
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Michel-Souzy S, Douzi B, Cadoret F, Raynaud C, Quinton L, Ball G, Voulhoux R. Direct interactions between the secreted effector and the T2SS components GspL and GspM reveal a new effector-sensing step during type 2 secretion. J Biol Chem 2018; 293:19441-19450. [PMID: 30337370 DOI: 10.1074/jbc.ra117.001127] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 10/04/2018] [Indexed: 12/11/2022] Open
Abstract
In many Gram-negative bacteria, the type 2 secretion system (T2SS) plays an important role in virulence because of its capacity to deliver a large amount of fully folded protein effectors to the extracellular milieu. Despite our knowledge of most T2SS components, the mechanisms underlying effector recruitment and secretion by the T2SS remain enigmatic. Using complementary biophysical and biochemical approaches, we identified here two direct interactions between the secreted effector CbpD and two components, XcpYL and XcpZM, of the T2SS assembly platform (AP) in the opportunistic pathogen Pseudomonas aeruginosa Competition experiments indicated that CbpD binding to XcpYL is XcpZM-dependent, suggesting sequential recruitment of the effector by the periplasmic domains of these AP components. Using a bacterial two-hybrid system, we then tested the influence of the effector on the AP protein-protein interaction network. Our findings revealed that the presence of the effector modifies the AP interactome and, in particular, induces XcpZM homodimerization and increases the affinity between XcpYL and XcpZM The observed direct relationship between effector binding and T2SS dynamics suggests an additional synchronizing step during the type 2 secretion process, where the activation of the AP of the T2SS nanomachine is triggered by effector binding.
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Affiliation(s)
- Sandra Michel-Souzy
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France
| | - Badreddine Douzi
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France.,CNRS, Aix Marseille Université, IMM, Laboratoire de Chimie Bactérienne (LCB)/UMR7283, 13009 Marseille, France, and
| | - Frédéric Cadoret
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France
| | - Claire Raynaud
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France.,CNRS, Aix Marseille Université, IMM, Laboratoire de Chimie Bactérienne (LCB)/UMR7283, 13009 Marseille, France, and
| | - Loïc Quinton
- Laboratory of Mass Spectrometry-MolSys, Department of Chemistry, University of Liège, B4000 Liège, Belgium
| | - Geneviève Ball
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France.,CNRS, Aix Marseille Université, IMM, Laboratoire de Chimie Bactérienne (LCB)/UMR7283, 13009 Marseille, France, and
| | - Romé Voulhoux
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France, .,CNRS, Aix Marseille Université, IMM, Laboratoire de Chimie Bactérienne (LCB)/UMR7283, 13009 Marseille, France, and
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31
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Type IX secretion system PorM and gliding machinery GldM form arches spanning the periplasmic space. Nat Commun 2018; 9:429. [PMID: 29382829 PMCID: PMC5790014 DOI: 10.1038/s41467-017-02784-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 12/29/2017] [Indexed: 11/08/2022] Open
Abstract
Type IX secretion system (T9SS), exclusively present in the Bacteroidetes phylum, has been studied mainly in Flavobacterium johnsoniae and Porphyromonas gingivalis. Among the 18 genes, essential for T9SS function, a group of four, porK-N (P. gingivalis) or gldK-N (F. johnsoniae) belongs to a co-transcribed operon that expresses the T9SS core membrane complex. The central component of this complex, PorM (or GldM), is anchored in the inner membrane by a trans-membrane helix and interacts through the outer membrane PorK-N complex. There is a complete lack of available atomic structures for any component of T9SS, including the PorKLMN complex. Here we report the crystal structure of the GldM and PorM periplasmic domains. Dimeric GldM and PorM, each contain four domains of ~180-Å length that span most of the periplasmic space. These and previously reported results allow us to propose a model of the T9SS core membrane complex as well as its functional behavior.
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32
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Structural Basis of Type 2 Secretion System Engagement between the Inner and Outer Bacterial Membranes. mBio 2017; 8:mBio.01344-17. [PMID: 29042496 PMCID: PMC5646249 DOI: 10.1128/mbio.01344-17] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sophisticated nanomachines are used by bacteria for protein secretion. In Gram-negative bacteria, the type 2 secretion system (T2SS) is composed of a pseudopilus assembly platform in the inner membrane and a secretin complex in the outer membrane. The engagement of these two megadalton-sized complexes is required in order to secrete toxins, effectors, and hydrolytic enzymes. Pseudomonas aeruginosa has at least two T2SSs, with the ancestral nanomachine having a secretin complex composed of XcpQ. Until now, no high-resolution structural information was available to distinguish the features of this Pseudomonas-type secretin, which varies greatly in sequence from the well-characterized Klebsiella-type and Vibrio-type secretins. We have purified the ~1-MDa secretin complex and analyzed it by cryo-electron microscopy. Structural comparisons with the Klebsiella-type secretin complex revealed a striking structural homology despite the differences in their sequence characteristics. At 3.6-Å resolution, the secretin complex was found to have 15-fold symmetry throughout the membrane-embedded region and through most of the domains in the periplasm. However, the N1 domain and N0 domain were not well ordered into this 15-fold symmetry. We suggest a model wherein this disordering of the subunit symmetry for the periplasmic N domains provides a means to engage with the 6-fold symmetry in the inner membrane platform, with a metastable engagement that can be disrupted by substrate proteins binding to the region between XcpP, in the assembly platform, and the XcpQ secretin. How the outer membrane and inner membrane components of the T2SS engage each other and yet can allow for substrate uptake into the secretin chamber has challenged the protein transport field for some time. This vexing question is of significance because the T2SS collects folded protein substrates in the periplasm for transport out of the bacterium and yet must discriminate these few substrate proteins from all the other hundred or so folded proteins in the periplasm. The structural analysis here supports a model wherein substrates must compete against a metastable interaction between XcpP in the assembly platform and the XcpQ secretin, wherein only structurally encoded features in the T2SS substrates compete well enough to disrupt XcpQ-XcpP for entry into the XcpQ chamber, for secretion across the outer membrane.
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33
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Unraveling the Self-Assembly of the Pseudomonas aeruginosa XcpQ Secretin Periplasmic Domain Provides New Molecular Insights into Type II Secretion System Secreton Architecture and Dynamics. mBio 2017; 8:mBio.01185-17. [PMID: 29042493 PMCID: PMC5646246 DOI: 10.1128/mbio.01185-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The type II secretion system (T2SS) releases large folded exoproteins across the envelope of many Gram-negative pathogens. This secretion process therefore requires specific gating, interacting, and dynamics properties mainly operated by a bipartite outer membrane channel called secretin. We have a good understanding of the structure-function relationship of the pore-forming C-terminal domain of secretins. In contrast, the high flexibility of their periplasmic N-terminal domain has been an obstacle in obtaining the detailed structural information required to uncover its molecular function. In Pseudomonas aeruginosa, the Xcp T2SS plays an important role in bacterial virulence by its capacity to deliver a large panel of toxins and degradative enzymes into the surrounding environment. Here, we revealed that the N-terminal domain of XcpQ secretin spontaneously self-assembled into a hexamer of dimers independently of its C-terminal domain. Furthermore, and by using multidisciplinary approaches, we elucidate the structural organization of the XcpQ N domain and demonstrate that secretin flexibility at interdimer interfaces is mandatory for its function. Bacterial secretins are large homooligomeric proteins constituting the outer membrane pore-forming element of several envelope-embedded nanomachines essential in bacterial survival and pathogenicity. They comprise a well-defined membrane-embedded C-terminal domain and a modular periplasmic N-terminal domain involved in substrate recruitment and connection with inner membrane components. We are studying the XcpQ secretin of the T2SS present in the pathogenic bacterium Pseudomonas aeruginosa. Our data highlight the ability of the XcpQ N-terminal domain to spontaneously oligomerize into a hexamer of dimers. Further in vivo experiments revealed that this domain adopts different conformations essential for the T2SS secretion process. These findings provide new insights into the functional understanding of bacterial T2SS secretins.
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34
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Waack U, Johnson TL, Chedid K, Xi C, Simmons LA, Mobley HLT, Sandkvist M. Targeting the Type II Secretion System: Development, Optimization, and Validation of a High-Throughput Screen for the Identification of Small Molecule Inhibitors. Front Cell Infect Microbiol 2017; 7:380. [PMID: 28894700 PMCID: PMC5581314 DOI: 10.3389/fcimb.2017.00380] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/09/2017] [Indexed: 12/26/2022] Open
Abstract
Nosocomial pathogens that develop multidrug resistance present an increasing problem for healthcare facilities. Due to its rapid rise in antibiotic resistance, Acinetobacter baumannii is one of the most concerning gram-negative species. A. baumannii typically infects immune compromised individuals resulting in a variety of outcomes, including pneumonia and bacteremia. Using a murine model for bacteremia, we have previously shown that the type II secretion system (T2SS) contributes to in vivo fitness of A. baumannii. Here, we provide support for a role of the T2SS in protecting A. baumannii from human complement as deletion of the T2SS gene gspD resulted in a 100-fold reduction in surviving cells when incubated with human serum. This effect was abrogated in the absence of Factor B, a component of the alternative pathway of complement activation, indicating that the T2SS protects A. baumannii against the alternative complement pathway. Because inactivation of the T2SS results in loss of secretion of multiple enzymes, reduced in vivo fitness, and increased sensitivity to human complement, the T2SS may be a suitable target for therapeutic intervention. Accordingly, we developed and optimized a whole-cell high-throughput screening (HTS) assay based on secreted lipase activity to identify small molecule inhibitors of the T2SS. We tested the reproducibility of our assay using a 6,400-compound library. With small variation within controls and a dynamic range between positive and negative controls, the assay had a z-factor of 0.65, establishing its suitability for HTS. Our screen identified the lipase inhibitors Orlistat and Ebelactone B demonstrating the specificity of the assay. To eliminate inhibitors of lipase activity and lipase expression, two counter assays were developed and optimized. By implementing these assays, all seven tricyclic antidepressants present in the library were found to be inhibitors of the lipase, highlighting the potential of identifying alternative targets for approved pharmaceuticals. Although no T2SS inhibitor was identified among the compounds that reduced lipase activity by ≥30%, our small proof-of-concept pilot study indicates that the HTS regimen is simple, reproducible, and specific and that it can be used to screen larger libraries for the identification of T2SS inhibitors that may be developed into novel A. baumannii therapeutics.
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Affiliation(s)
- Ursula Waack
- Department of Microbiology and Immunology, University of Michigan Medical SchoolAnn Arbor, MI, United States
| | - Tanya L Johnson
- Department of Microbiology and Immunology, University of Michigan Medical SchoolAnn Arbor, MI, United States.,Department of Chemistry, Eastern Michigan UniversityYpsilanti, MI, United States
| | - Khalil Chedid
- Department of Microbiology and Immunology, University of Michigan Medical SchoolAnn Arbor, MI, United States
| | - Chuanwu Xi
- Department of Environmental Health Sciences, University of Michigan School of Public HealthAnn Arbor, MI, United States
| | - Lyle A Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of MichiganAnn Arbor, MI, United States
| | - Harry L T Mobley
- Department of Microbiology and Immunology, University of Michigan Medical SchoolAnn Arbor, MI, United States
| | - Maria Sandkvist
- Department of Microbiology and Immunology, University of Michigan Medical SchoolAnn Arbor, MI, United States
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35
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Gu S, Shevchik VE, Shaw R, Pickersgill RW, Garnett JA. The role of intrinsic disorder and dynamics in the assembly and function of the type II secretion system. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1255-1266. [PMID: 28733198 DOI: 10.1016/j.bbapap.2017.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/02/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Many Gram-negative commensal and pathogenic bacteria use a type II secretion system (T2SS) to transport proteins out of the cell. These exported proteins or substrates play a major role in toxin delivery, maintaining biofilms, replication in the host and subversion of host immune responses to infection. We review the current structural and functional work on this system and argue that intrinsically disordered regions and protein dynamics are central for assembly, exo-protein recognition, and secretion competence of the T2SS. The central role of intrinsic disorder-order transitions in these processes may be a particular feature of type II secretion.
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Affiliation(s)
- Shuang Gu
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom
| | - Vladimir E Shevchik
- Université de Lyon, F-69003, Université Lyon 1, Lyon, F-69622, INSA-Lyon, Villeurbanne F-69621, CNRS, UMR5240, Microbiologie Adaptation et Pathogénie, Lyon F-69622, France
| | - Rosie Shaw
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom
| | - Richard W Pickersgill
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom.
| | - James A Garnett
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom.
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36
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Thomassin JL, Santos Moreno J, Guilvout I, Tran Van Nhieu G, Francetic O. The trans-envelope architecture and function of the type 2 secretion system: new insights raising new questions. Mol Microbiol 2017; 105:211-226. [DOI: 10.1111/mmi.13704] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Jenny-Lee Thomassin
- Department of structural biology and chemistry, Biochemistry of Macromolecular Interactions Unit; Institut Pasteur; 28 rue du Dr Roux 75724 Paris Cedex 15 France
- Centre National de la Recherche Scientifique (CNRS); ERL6002 75724 Paris France
| | - Javier Santos Moreno
- Université Paris Diderot (Paris 7) Sorbonne Paris Cité; Paris France
- Laboratory of Intercellular Communication and Microbial Infections; CIRB, Collège de France; 11 Place Marcelin Berthelot 75005 Paris France
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1050; 75005 Paris France
- Centre National de la Recherche Scientifique (CNRS), UMR7241; 75005 Paris France
- MEMOLIFE Laboratory of Excellence and Paris Sciences et Lettres; 75005 Paris France
| | - Ingrid Guilvout
- Department of structural biology and chemistry, Biochemistry of Macromolecular Interactions Unit; Institut Pasteur; 28 rue du Dr Roux 75724 Paris Cedex 15 France
- Centre National de la Recherche Scientifique (CNRS); ERL6002 75724 Paris France
| | - Guy Tran Van Nhieu
- Laboratory of Intercellular Communication and Microbial Infections; CIRB, Collège de France; 11 Place Marcelin Berthelot 75005 Paris France
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1050; 75005 Paris France
- Centre National de la Recherche Scientifique (CNRS), UMR7241; 75005 Paris France
- MEMOLIFE Laboratory of Excellence and Paris Sciences et Lettres; 75005 Paris France
| | - Olivera Francetic
- Department of structural biology and chemistry, Biochemistry of Macromolecular Interactions Unit; Institut Pasteur; 28 rue du Dr Roux 75724 Paris Cedex 15 France
- Centre National de la Recherche Scientifique (CNRS); ERL6002 75724 Paris France
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Alterations in Peptidoglycan Cross-Linking Suppress the Secretin Assembly Defect Caused by Mutation of GspA in the Type II Secretion System. J Bacteriol 2017; 199:JB.00617-16. [PMID: 28138102 DOI: 10.1128/jb.00617-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 01/23/2017] [Indexed: 12/22/2022] Open
Abstract
In Gram-negative bacteria, the peptidoglycan (PG) cell wall is a significant structural barrier for outer membrane protein assembly. In Aeromonas hydrophila, outer membrane multimerization of the type II secretion system (T2SS) secretin ExeD requires the function of the inner membrane assembly factor complex ExeAB. The putative mechanism of the complex involves the reorganization of PG and localization of ExeD, whereby ExeA functions by interacting with PG to form a site for secretin assembly and ExeB forms an interaction with ExeD. This mechanism led us to hypothesize that increasing the pore size of PG would circumvent the requirement for ExeA in the assembly of the ExeD secretin. Growth of A. hydrophila in 270 mM Gly reduced PG cross-links by approximately 30% and led to the suppression of secretin assembly defects in exeA strains and in those expressing ExeA mutants by enabling localization of the secretin in the outer membrane. We also established a heterologous ExeD assembly system in Escherichia coli and showed that ExeAB and ExeC are the only A. hydrophila proteins required for the assembly of the ExeD secretin in E. coli and that ExeAB-independent assembly of ExeD can occur upon overexpression of the d,d-carboxypeptidase PBP 5. These results support an assembly model in which, upon binding to PG, ExeA induces multimerization and pore formation in the sacculus, which enables ExeD monomers to interact with ExeB and assemble into a secretin that both is inserted in the outer membrane and crosses the PG layer to interact with the inner membrane platform of the T2SS.IMPORTANCE The PG layer imposes a strict structural impediment for the assembly of macromolecular structures that span the cell envelope and serve as virulence factors in Gram-negative species. This work revealed that by decreasing PG cross-linking by growth in Gly, the absolute requirement for the PG-binding activity of ExeA in the assembly of the ExeD secretin was alleviated in A. hydrophila In a heterologous assembly model in E. coli, expression of the carboxypeptidase PBP 5 could relieve the requirement for ExeAB in the assembly of the ExeD secretin. These results provide some mechanistic details of the ExeAB assembly complex function, in which the PG-binding and oligomerization functions of ExeAB are used to create a pore in the PG that is required for secretin assembly.
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Abstract
Surface plasmon resonance (SPR) is one of the most commonly used techniques to study protein-protein interactions. The main advantage of SPR is it gives on the ability to measure the binding affinities and association/dissociation kinetics of complexes in real time, in a label-free environment, and using relatively small quantities of materials. The method is based on the immobilization of one of the binding partners, called the ligand, on a dedicated sensor surface. Immobilization is followed by the injection of the other partner, called the analyte, over the surface containing the ligand. The binding is monitored by subsequent changes in the refractive index of the medium close to the sensor surface upon injection of the analyte. During the last 10 years, SPR has been intensively used in the study of secretion systems because of its ability to detect highly dynamic complexes that are difficult to investigate using other techniques. This chapter will guide users in the setup of SPR experiments in order to identify protein complexes and to assess their binding affinity or kinetics. It will include detailed protocols for (i) the immobilization of proteins with the amine coupling capture method, (ii) analyte-binding analysis, (iii) affinity/kinetic measurements, and (iv) data analysis.Secretion systems are multiprotein complexes allowing the transport of a large number of effectors from the inside to the outside of bacterial cells. The assembly of these supramolecular machineries is ensured by the formation of protein complexes with extremely different times of stability, from transitory to stable interactions. To understand the function of these machineries as well as their modes of association, it is important to study their building blocks by identifying the different interacting partners and assessing their relative affinities and association/dissociation kinetics. For that purpose, scientists combine genetic, biochemical, and biophysical tools. During the last decade, the use of surface plasmon resonance (SPR) in the study of secretion systems has increased spectacularly [1-12]. This in vitro approach is the method of choice to study such dynamic systems owing to its ability to detect both weak and strong interactions ranging from the millimolar to the nanomolar range [13, 14]. SPR can be used as a primary tool to screen interacting partners or as a validation tool for interactions previously identified by other methods (e.g., bacterial two-hybrid, co-immunoprecipitation, chemical crosslinking). The determination of the affinity or kinetics of an interaction, as can be done by SPR, is fundamental to understanding the nature of binding at the cellular level.
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Affiliation(s)
- Badreddine Douzi
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR 7255), Institut de Microbiologie de la Méditerranée (IMM), Aix-Marseille Université-Centre National de la Recherche Scientifique (CNRS), 31 Chemin Joseph Aiguier, 13402, Marseille Cedex 20, France.
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Ng D, Harn T, Altindal T, Kolappan S, Marles JM, Lala R, Spielman I, Gao Y, Hauke CA, Kovacikova G, Verjee Z, Taylor RK, Biais N, Craig L. The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus. PLoS Pathog 2016; 12:e1006109. [PMID: 27992883 PMCID: PMC5207764 DOI: 10.1371/journal.ppat.1006109] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/03/2017] [Accepted: 12/02/2016] [Indexed: 01/03/2023] Open
Abstract
Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system. Bacterial pathogens utilize a number of highly complex and sophisticated molecular systems to colonize their hosts and alter them, creating customized niches in which to reproduce. One such system is the Type IV pilus system, made up of dozens of proteins that form a macromolecular machine to polymerize small pilin proteins into long thin filaments that are displayed on the bacterial surface. These pili have a remarkable array of functions that rely on their ability to (i) adhere to many substrates, including host cell surfaces, pili from nearby bacteria, DNA and bacterial viruses (bacteriophage), and (ii) to depolymerize or retract, which pulls the bacteria along mucosal surfaces, pulls them close together in protective aggregates, and can even draw in substrates like DNA and bacteriophage for nutrition and genetic variation. For most Type IV pilus systems, retraction is an energy-driven process facilitated by a retraction ATPase. We show here that in the simplest of the Type IV pilus systems, the Vibrio cholerae toxin-coregulated pilus, a pilin-like protein initiates pilus retraction by what appears to be mechanical rather than enzymatic means. Our results provide a framework for understanding more complex Type IV pili and the related Type II secretion systems, which represent targets for novel highly specific antibiotics.
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Affiliation(s)
- Dixon Ng
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Tony Harn
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Tuba Altindal
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Subramania Kolappan
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Jarrad M. Marles
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Rajan Lala
- Biology Department, Brooklyn College, City University of New York, Brooklyn, New York, United States of America
| | - Ingrid Spielman
- Biology Department, Brooklyn College, City University of New York, Brooklyn, New York, United States of America
| | - Yang Gao
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Caitlyn A. Hauke
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Gabriela Kovacikova
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Zia Verjee
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Ronald K. Taylor
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Nicolas Biais
- Biology Department, Brooklyn College, City University of New York, Brooklyn, New York, United States of America
- Graduate Center, City University of New York, Brooklyn, New York, United States of America
- * E-mail: (LC); (NB)
| | - Lisa Craig
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- * E-mail: (LC); (NB)
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Caminero A, Galipeau HJ, McCarville JL, Johnston CW, Bernier SP, Russell AK, Jury J, Herran AR, Casqueiro J, Tye-Din JA, Surette MG, Magarvey NA, Schuppan D, Verdu EF. Duodenal Bacteria From Patients With Celiac Disease and Healthy Subjects Distinctly Affect Gluten Breakdown and Immunogenicity. Gastroenterology 2016; 151:670-83. [PMID: 27373514 DOI: 10.1053/j.gastro.2016.06.041] [Citation(s) in RCA: 151] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/22/2016] [Accepted: 06/23/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Partially degraded gluten peptides from cereals trigger celiac disease (CD), an autoimmune enteropathy occurring in genetically susceptible persons. Susceptibility genes are necessary but not sufficient to induce CD, and additional environmental factors related to unfavorable alterations in the microbiota have been proposed. We investigated gluten metabolism by opportunistic pathogens and commensal duodenal bacteria and characterized the capacity of the produced peptides to activate gluten-specific T-cells from CD patients. METHODS We colonized germ-free C57BL/6 mice with bacteria isolated from the small intestine of CD patients or healthy controls, selected for their in vitro gluten-degrading capacity. After gluten gavage, gliadin amount and proteolytic activities were measured in intestinal contents. Peptides produced by bacteria used in mouse colonizations from the immunogenic 33-mer gluten peptide were characterized by liquid chromatography tandem mass spectrometry and their immunogenic potential was evaluated using peripheral blood mononuclear cells from celiac patients after receiving a 3-day gluten challenge. RESULTS Bacterial colonizations produced distinct gluten-degradation patterns in the mouse small intestine. Pseudomonas aeruginosa, an opportunistic pathogen from CD patients, exhibited elastase activity and produced peptides that better translocated the mouse intestinal barrier. P aeruginosa-modified gluten peptides activated gluten-specific T-cells from CD patients. In contrast, Lactobacillus spp. from the duodenum of non-CD controls degraded gluten peptides produced by human and P aeruginosa proteases, reducing their immunogenicity. CONCLUSIONS Small intestinal bacteria exhibit distinct gluten metabolic patterns in vivo, increasing or reducing gluten peptide immunogenicity. This microbe-gluten-host interaction may modulate autoimmune risk in genetically susceptible persons and may underlie the reported association of dysbiosis and CD.
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Affiliation(s)
- Alberto Caminero
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Heather J Galipeau
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Justin L McCarville
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Chad W Johnston
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Steve P Bernier
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Amy K Russell
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Jennifer Jury
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Alexandra R Herran
- Área de Microbiología, Facultad de Biología y Ciencias Ambientales, Universidad de León, León, Spain
| | - Javier Casqueiro
- Área de Microbiología, Facultad de Biología y Ciencias Ambientales, Universidad de León, León, Spain
| | - Jason A Tye-Din
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia; Department of Gastroenterology, The Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Michael G Surette
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada; Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Nathan A Magarvey
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Detlef Schuppan
- Institute for Translational Immunology and Research Center for Immunotherapy, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Elena F Verdu
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada.
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Kawahara K, Oki H, Fukakusa S, Yoshida T, Imai T, Maruno T, Kobayashi Y, Motooka D, Iida T, Ohkubo T, Nakamura S. Homo-trimeric Structure of the Type IVb Minor Pilin CofB Suggests Mechanism of CFA/III Pilus Assembly in Human Enterotoxigenic Escherichia coli. J Mol Biol 2016; 428:1209-1226. [PMID: 26876601 DOI: 10.1016/j.jmb.2016.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/30/2016] [Accepted: 02/03/2016] [Indexed: 11/18/2022]
Abstract
In gram-negative bacteria, the assembly of type IV pilus (T4P) and the evolutionally related pseudopilus of type II secretion system involves specialized structural proteins called pilins and pseudopilins, respectively, and is dynamically regulated to promote bacterial pathogenesis. Previous studies have suggested that a structural "tip"-like hetero-complex formed through the interaction of at least three minor (pseudo) pilins plays an important role in this process, while some members of the pathogenic type IVb subfamily are known to have only one such minor pilin subunit whose function is still unknown. Here, we determined the crystal structure of the type IVb minor pilin CofB of colonization factor antigen/III from human enterotoxigenic Escherichia coli at 1.88-Å resolution. The crystal structure, in conjunction with physicochemical analysis in solution, reveals a symmetrical homo-trimeric arrangement distinct from the hetero-complexes of minor (pseudo) pilins observed in other T4P and type II secretion systems. Each CofB monomer adopts a unique three-domain architecture, in which the C-terminal β-sheet-rich lectin domain can effectively initiate trimer association of its pilin-like N-terminal domain through extensive hydrophobic interactions followed by domain swapping at the central hinge-like domain. Deletion of cofB produces a phenotype with no detectable pili formation on the cell surface, while molecular modeling indicates that the characteristic homo-trimeric structure of CofB is well situated at the pilus tip of colonization factor antigen/III formed by the major pilin CofA, suggesting a role for the minor pilin in the efficient initiation of T4P assembly.
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Affiliation(s)
- Kazuki Kawahara
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hiroya Oki
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shunsuke Fukakusa
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takuya Yoshida
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tomoya Imai
- Research Institute for Sustainable Humanosphere (RISH), Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takahiro Maruno
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuji Kobayashi
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Daisuke Motooka
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tetsuya Iida
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tadayasu Ohkubo
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shota Nakamura
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Affiliation(s)
- Alain Filloux
- Alain Filloux, MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; E-mail:
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43
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Berry JL, Pelicic V. Exceptionally widespread nanomachines composed of type IV pilins: the prokaryotic Swiss Army knives. FEMS Microbiol Rev 2014; 39:134-54. [PMID: 25793961 PMCID: PMC4471445 DOI: 10.1093/femsre/fuu001] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Prokaryotes have engineered sophisticated surface nanomachines that have allowed them to colonize Earth and thrive even in extreme environments. Filamentous machineries composed of type IV pilins, which are associated with an amazing array of properties ranging from motility to electric conductance, are arguably the most widespread since distinctive proteins dedicated to their biogenesis are found in most known species of prokaryotes. Several decades of investigations, starting with type IV pili and then a variety of related systems both in bacteria and archaea, have outlined common molecular and structural bases for these nanomachines. Using type IV pili as a paradigm, we will highlight in this review common aspects and key biological differences of this group of filamentous structures. Using type IV pili as a paradigm, we review common genetic, structural and mechanistic features (many) as well as differences (few) of the exceptionally widespread and functionally versatile prokaryotic nano-machines composed of type IV pilins.
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Affiliation(s)
- Jamie-Lee Berry
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Vladimir Pelicic
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
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Pineau C, Guschinskaya N, Robert X, Gouet P, Ballut L, Shevchik VE. Substrate recognition by the bacterial type II secretion system: more than a simple interaction. Mol Microbiol 2014; 94:126-40. [DOI: 10.1111/mmi.12744] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Camille Pineau
- Université Lyon 1; F-69622 Lyon France
- INSA-Lyon; F-69621 Villeurbanne France
- CNRS; UMR5240; Microbiologie Adaptation et Pathogénie; F-69622 Lyon France
| | - Natalia Guschinskaya
- Université Lyon 1; F-69622 Lyon France
- CNRS; UMR5240; Microbiologie Adaptation et Pathogénie; F-69622 Lyon France
| | - Xavier Robert
- Laboratory for Biocrystallography and Structural Biology of Therapeutic Targets; Molecular and Structural Bases of Infectious Diseases; CNRS; UMR5086; F-69367 Lyon France
| | - Patrice Gouet
- Laboratory for Biocrystallography and Structural Biology of Therapeutic Targets; Molecular and Structural Bases of Infectious Diseases; CNRS; UMR5086; F-69367 Lyon France
| | - Lionel Ballut
- Laboratory for Biocrystallography and Structural Biology of Therapeutic Targets; Molecular and Structural Bases of Infectious Diseases; CNRS; UMR5086; F-69367 Lyon France
| | - Vladimir E. Shevchik
- Université Lyon 1; F-69622 Lyon France
- INSA-Lyon; F-69621 Villeurbanne France
- CNRS; UMR5240; Microbiologie Adaptation et Pathogénie; F-69622 Lyon France
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Lu C, Korotkov KV, Hol WGJ. Crystal structure of the full-length ATPase GspE from the Vibrio vulnificus type II secretion system in complex with the cytoplasmic domain of GspL. J Struct Biol 2014; 187:223-235. [PMID: 25092625 DOI: 10.1016/j.jsb.2014.07.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 11/15/2022]
Abstract
The type II secretion system (T2SS) is present in many Gram-negative bacteria and is responsible for secreting a large number of folded proteins, including major virulence factors, across the outer membrane. The T2SS consists of 11-15 different proteins most of which are present in multiple copies in the assembled secretion machinery. The ATPase GspE, essential for the functioning of the T2SS, contains three domains (N1E, N2E and CTE) of which the N1E domain is associated with the cytoplasmic domain of the inner membrane protein GspL. Here we describe and analyze the structure of the GspE•cyto-GspL complex from Vibrio vulnificus in the presence of an ATP analog, AMPPNP. There are three such ∼83 kDa complexes per asymmetric unit with essentially the same structure. The N2E and CTE domains of a single V. vulnificus GspE subunit adopt a mutual orientation that has not been seen before in any of the previous GspE structures, neither in structures of related ATPases from other secretion systems. This underlines the tremendous conformational flexibility of the T2SS secretion ATPase. Cyto-GspL interacts not only with the N1E domain, but also with the CTE domain and is even in contact with AMPPNP. Moreover, the cyto-GspL domains engage in two types of mutual interactions, resulting in two essentially identical, but crystallographically independent, "cyto-GspL rods" that run throughout the crystal. Very similar rods are present in previous crystals of cyto-GspL and of the N1E•cyto-GspL complex. This arrangement, now seen four times in three entirely different crystal forms, involves contacts between highly conserved residues suggesting a role in the biogenesis or the secretion mechanism or both of the T2SS.
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Affiliation(s)
- Connie Lu
- Department of Biochemistry and Biomolecular Structure Center, University of Washington, Seattle, WA 98195, United States
| | - Konstantin V Korotkov
- Department of Biochemistry and Biomolecular Structure Center, University of Washington, Seattle, WA 98195, United States
| | - Wim G J Hol
- Department of Biochemistry and Biomolecular Structure Center, University of Washington, Seattle, WA 98195, United States.
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Type II secretion system: A magic beanstalk or a protein escalator. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1568-77. [DOI: 10.1016/j.bbamcr.2013.12.020] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 12/13/2013] [Accepted: 12/23/2013] [Indexed: 12/12/2022]
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47
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Vanderlinde EM, Zhong S, Li G, Martynowski D, Grochulski P, Howard SP. Assembly of the type two secretion system in Aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor ExeB and the secretin ExeD. PLoS One 2014; 9:e102038. [PMID: 25025769 PMCID: PMC4098917 DOI: 10.1371/journal.pone.0102038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 06/14/2014] [Indexed: 12/25/2022] Open
Abstract
The type two secretion system is a large, trans-envelope apparatus that secretes toxins across the outer membrane of many Gram-negative bacteria. In Aeromonas hydrophila, ExeA interacts with peptidoglycan and forms a heteromultimeric complex with ExeB that is required for assembly of the ExeD secretin of the secretion system in the outer membrane. While the peptidoglycan-ExeAB (PG-AB) complex is required for ExeD assembly, the assembly mechanism remains unresolved. We analyzed protein-protein interactions to address the hypothesis that ExeD assembly in the outer membrane requires direct interaction with the PG-AB complex. Yeast and bacterial two hybrid analyses demonstrated an interaction between the periplasmic domains of ExeB and ExeD. Two-codon insertion mutagenesis of exeD disrupted lipase secretion, and immunoblotting of whole cells demonstrated significantly reduced secretin in mutant cells. Mapping of the two-codon insertions and deletion analysis showed that the ExeB-ExeD interaction involves the N0 and N1 subdomains of ExeD. Rotational anisotropy using the purified periplasmic domains of ExeB and ExeD determined that the apparent dissociation constant of the interaction is 1.19±0.16 µM. These results contribute important support for a putative mechanism by which the PG-AB complex facilitates assembly of ExeD through direct interaction between ExeB and ExeD. Furthermore, our results provide novel insight into the assembly function of ExeB that may contribute to elucidating the role of homologous proteins in secretion of toxins from other Gram negative pathogens.
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Affiliation(s)
- Elizabeth M. Vanderlinde
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Su Zhong
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Gang Li
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Dariusz Martynowski
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Pawel Grochulski
- Canadian Light Source, Saskatoon, Saskatchewan, Canada
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - S. Peter Howard
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- * E-mail:
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48
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Cadoret F, Ball G, Douzi B, Voulhoux R. Txc, a new type II secretion system of Pseudomonas aeruginosa strain PA7, is regulated by the TtsS/TtsR two-component system and directs specific secretion of the CbpE chitin-binding protein. J Bacteriol 2014; 196:2376-86. [PMID: 24748613 PMCID: PMC4054165 DOI: 10.1128/jb.01563-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 04/11/2014] [Indexed: 01/20/2023] Open
Abstract
We present here the functional characterization of a third complete type II secretion system (T2SS) found in newly sequenced Pseudomonas aeruginosa strain PA7. We call this system Txc (third Xcp homolog). This system is encoded by the RGP69 region of genome plasticity found uniquely in strain PA7. In addition to the 11 txc genes, RGP69 contains two additional genes encoding a possible T2SS substrate and a predicted unorthodox sensor protein, TtsS (type II secretion sensor). We also identified a gene encoding a two-component response regulator called TtsR (type II secretion regulator), which is located upstream of the ttsS gene and just outside RGP69. We show that TtsS and TtsR constitute a new and functional two-component system that controls the production and secretion of the RGP69-encoded T2SS substrate in a Txc-dependent manner. Finally, we demonstrate that this Txc-secreted substrate binds chitin, and we therefore name it CbpE (chitin-binding protein E).
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Affiliation(s)
- Frédéric Cadoret
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM-UMR7255), CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Geneviève Ball
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM-UMR7255), CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Badreddine Douzi
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM-UMR7255), CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Romé Voulhoux
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM-UMR7255), CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, Marseille, France
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Distinct docking and stabilization steps of the Pseudopilus conformational transition path suggest rotational assembly of type IV pilus-like fibers. Structure 2014; 22:685-96. [PMID: 24685147 DOI: 10.1016/j.str.2014.03.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 02/28/2014] [Accepted: 03/04/2014] [Indexed: 01/07/2023]
Abstract
The closely related bacterial type II secretion (T2S) and type IV pilus (T4P) systems are sophisticated machines that assemble dynamic fibers promoting protein transport, motility, or adhesion. Despite their essential role in virulence, the molecular mechanisms underlying helical fiber assembly remain unknown. Here, we use electron microscopy and flexible modeling to study conformational changes of PulG pili assembled by the Klebsiella oxytoca T2SS. Neural network analysis of 3,900 pilus models suggested a transition path toward low-energy conformations driven by progressive increase in fiber helical twist. Detailed predictions of interprotomer contacts along this path were tested by site-directed mutagenesis, pilus assembly, and protein secretion analyses. We demonstrate that electrostatic interactions between adjacent protomers (P-P+1) in the membrane drive pseudopilin docking, while P-P+3 and P-P+4 contacts determine downstream fiber stabilization steps. These results support a model of a spool-like assembly mechanism for fibers of the T2SS-T4P superfamily.
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Golovkine G, Faudry E, Bouillot S, Voulhoux R, Attrée I, Huber P. VE-cadherin cleavage by LasB protease from Pseudomonas aeruginosa facilitates type III secretion system toxicity in endothelial cells. PLoS Pathog 2014; 10:e1003939. [PMID: 24626230 PMCID: PMC3953407 DOI: 10.1371/journal.ppat.1003939] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 01/06/2014] [Indexed: 01/01/2023] Open
Abstract
Infection of the vascular system by Pseudomonas aeruginosa (Pa) occurs during bacterial dissemination in the body or in blood-borne infections. Type 3 secretion system (T3SS) toxins from Pa induce a massive retraction when injected into endothelial cells. Here, we addressed the role of type 2 secretion system (T2SS) effectors in this process. Mutants with an inactive T2SS were much less effective than wild-type strains at inducing cell retraction. Furthermore, secretomes from wild-types were sufficient to trigger cell-cell junction opening when applied to cells, while T2SS-inactivated mutants had minimal activity. Intoxication was associated with decreased levels of vascular endothelial (VE)-cadherin, a homophilic adhesive protein located at endothelial cell-cell junctions. During the process, the protein was cleaved in the middle of its extracellular domain (positions 335 and 349). VE-cadherin attrition was T3SS-independent but T2SS-dependent. Interestingly, the epithelial (E)-cadherin was unaffected by T2SS effectors, indicating that this mechanism is specific to endothelial cells. We showed that one of the T2SS effectors, the protease LasB, directly affected VE-cadherin proteolysis, hence promoting cell-cell junction disruption. Furthermore, mouse infection with Pa to induce acute pneumonia lead to significant decreases in lung VE-cadherin levels, whereas the decrease was minimal with T2SS-inactivated or LasB-deleted mutant strains. We conclude that the T2SS plays a pivotal role during Pa infection of the vascular system by breaching the endothelial barrier, and propose a model in which the T2SS and the T3SS cooperate to intoxicate endothelial cells.
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Affiliation(s)
- Guillaume Golovkine
- INSERM, U1036, Biology of Cancer and Infection, Grenoble, France
- CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France
- Université Joseph Fourier-Grenoble I, Grenoble, France
- CEA, DSV/iRTSV, Grenoble, France
| | - Eric Faudry
- INSERM, U1036, Biology of Cancer and Infection, Grenoble, France
- CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France
- Université Joseph Fourier-Grenoble I, Grenoble, France
- CEA, DSV/iRTSV, Grenoble, France
| | - Stéphanie Bouillot
- INSERM, U1036, Biology of Cancer and Infection, Grenoble, France
- CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France
- Université Joseph Fourier-Grenoble I, Grenoble, France
- CEA, DSV/iRTSV, Grenoble, France
| | - Romé Voulhoux
- CNRS and Aix-Marseille Univ, Laboratoire d'Ingénierie des Systèmes Macromoléculaires (UMR7255), Marseille, France
| | - Ina Attrée
- INSERM, U1036, Biology of Cancer and Infection, Grenoble, France
- CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France
- Université Joseph Fourier-Grenoble I, Grenoble, France
- CEA, DSV/iRTSV, Grenoble, France
| | - Philippe Huber
- INSERM, U1036, Biology of Cancer and Infection, Grenoble, France
- CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France
- Université Joseph Fourier-Grenoble I, Grenoble, France
- CEA, DSV/iRTSV, Grenoble, France
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