title: Biogenesis and structure of a type VI secretion membrane core complex.
abstract: Bacteria share their ecological niches with other microbes. The bacterial type VI secretion system is one of the key players in microbial competition, as well as being an important virulence determinant during bacterial infections. It assembles a nano-crossbow-like structure in the cytoplasm of the attacker cell that propels an arrow made of a haemolysin co-regulated protein (Hcp) tube and a valine-glycine repeat protein G (VgrG) spike and punctures the prey's cell wall. The nano-crossbow is stably anchored to the cell envelope of the attacker by a membrane core complex. Here we show that this complex is assembled by the sequential addition of three type VI subunits (Tss)-TssJ, TssM and TssL-and present a structure of the fully assembled complex at 11.6 Å resolution, determined by negative-stain electron microscopy. With overall C5 symmetry, this 1.7-megadalton complex comprises a large base in the cytoplasm. It extends in the periplasm via ten arches to form a double-ring structure containing the carboxy-terminal domain of TssM (TssMct) and TssJ that is anchored in the outer membrane. The crystal structure of the TssMct-TssJ complex coupled to whole-cell accessibility studies suggest that large conformational changes induce transient pore formation in the outer membrane, allowing passage of the attacking Hcp tube/VgrG spike.
authors.affiliation: 1] Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Aix-Marseille Université - CNRS, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France [2] Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France [3] G5 Biologie structurale de la sécrétion bactérienne, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France [4] UMR 3528, CNRS, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France [5] AFMB, Aix-Marseille Université, IHU Méditerranée Infection, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Durand
authors.affiliation: 1] Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France [2] AFMB, Aix-Marseille Université, IHU Méditerranée Infection, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France.
authors.forename: Van Son
authors.initials: VS
authors.lastname: Nguyen
authors.affiliation: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Aix-Marseille Université - CNRS, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
authors.forename: Abdelrahim
authors.initials: A
authors.lastname: Zoued
authors.affiliation: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Aix-Marseille Université - CNRS, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
authors.forename: Laureen
authors.initials: L
authors.lastname: Logger
authors.affiliation: UMR 3528, CNRS, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Péhau-Arnaudet
authors.affiliation: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Aix-Marseille Université - CNRS, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
authors.forename: Marie-Stéphanie
authors.initials: MS
authors.lastname: Aschtgen
authors.affiliation: 1] Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France [2] AFMB, Aix-Marseille Université, IHU Méditerranée Infection, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France.
authors.forename: Silvia
authors.initials: S
authors.lastname: Spinelli
authors.affiliation: 1] Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France [2] AFMB, Aix-Marseille Université, IHU Méditerranée Infection, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France.
authors.forename: Aline
authors.initials: A
authors.lastname: Desmyter
authors.affiliation: 1] UMR 3528, CNRS, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France [2] Unité de Bioinformatique Structurale, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Bardiaux
authors.affiliation: 1] G5 Biologie structurale de la sécrétion bactérienne, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France [2] UMR 3528, CNRS, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France.
authors.forename: Annick
authors.initials: A
authors.lastname: Dujeancourt
authors.affiliation: 1] Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France [2] AFMB, Aix-Marseille Université, IHU Méditerranée Infection, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Roussel
authors.affiliation: 1] Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France [2] AFMB, Aix-Marseille Université, IHU Méditerranée Infection, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Cambillau
authors.affiliation: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Aix-Marseille Université - CNRS, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Cascales
authors.affiliation: 1] G5 Biologie structurale de la sécrétion bactérienne, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France [2] UMR 3528, CNRS, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Fronzes
mesh_terms: D058947:Bacterial Secretion Systems; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D003593:Cytoplasm / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000737:chemistry*; D055666:Lipopeptides / Q000096:biosynthesis / Q000737:chemistry*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry*; D008854:Microscopy, Electron; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000096:biosynthesis* / Q000737:chemistry*; D019897:Periplasm / Q000737:chemistry / Q000378:metabolism; D016062:Porosity; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000096:biosynthesis / Q000737:chemistry
chemical_list: D058947:Bacterial Secretion Systems; D029968:Escherichia coli Proteins; D055666:Lipopeptides; D008565:Membrane Proteins; D046912:Multiprotein Complexes; D021122:Protein Subunits; C572322:TssJ protein, E coli; C573566:TssL protein, E coli; C000600302:TssM protein, E coli