RAPISARDA, Chiara; CHERRAK, Yassine; KOOGER, Romain; SCHMIDT, Victoria; PELLARIN, Riccardo; LOGGER, Laureen; CASCALES, Eric; PILHOFER, Martin; DURAND, Eric; FRONZES, Remi

RAPISARDA, Chiara
Microbiologie Fondamentale et Pathogénicité [MFP]

CHERRAK, Yassine
Laboratoire d'ingénierie des systèmes macromoléculaires [LISM]

KOOGER, Romain
Institute of Biochemistry [ETH Zürich]

Langue

Article de revue

Ce document a été publié dans

EMBO Journal. 2019-05-15, vol. 38, n° 10

Résumé en anglais

Bacteria have evolved macromolecular machineries that secrete effectors and toxins to survive and thrive in diverse environments. The type VI secretion system (T6SS) is a contractile machine that is related to phages. It is composed of a phage tail-like structure inserted in the bacterial cell envelope by a membrane complex (MC) comprising the TssJ, TssL and TssM proteins. We previously reported the low-resolution negative-stain electron microscopy structure of the enteroaggregative MC and proposed a rotational 5-fold symmetry with a TssJ:TssL:TssM stoichiometry of 2:2:2. Here, cryo-electron tomography analyses of the T6SS MC confirm the 5-fold symmetry and identify the regions of the structure that insert into the bacterial membranes. A high-resolution model obtained by single-particle cryo-electron microscopy highlights new features: five additional copies of TssJ, yielding a TssJ:TssL:TssM stoichiometry of 3:2:2, an 11-residue loop in TssM, protruding inside the lumen of the MC and constituting a functionally important periplasmic gate, and hinge regions. Based on these data, we propose an updated model on MC structure and dynamics during T6SS assembly and function.< Réduire

Mots clés en anglais

Bacterial Secretion Systems

Cell Membrane

Cryoelectron Microscopy

Escherichia coli

Escherichia coli Proteins

Membrane Proteins

Models

Molecular

Protein Binding

Protein Structure

Quaternary

Type VI Secretion Systems

URI

https://oskar-bordeaux.fr/handle/20.500.12278/184854

Unités de recherche

MFP (Laboratoire Microbiologie Fondamentale et Pathogénicité) - UMR 5234

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In situ and high-resolution Cryo-EM structure of the Type VI secretion membrane complex

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Résumé en anglais

Mots clés en anglais

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Unités de recherche