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Cryo-EM structure of the extended type VI secretion system sheath-tube complex

Item Type:Article
Title:Cryo-EM structure of the extended type VI secretion system sheath-tube complex
Creators Name:Wang, J. and Brackmann, M. and Castaño-Díez, D. and Kudryashev, M. and Goldie, K.N. and Maier, T. and Stahlberg, H. and Basler, M.
Abstract:The bacterial type VI secretion system (T6SS) uses contraction of a long sheath to quickly thrust a tube with associated effectors across membranes of eukaryotic and bacterial cells. Only limited structural information is available about the inherently unstable precontraction state of the T6SS. Here, we obtain a 3.7 Å resolution structure of a non-contractile sheath-tube complex using cryo-electron microscopy and show that it resembles the extended T6SS inside Vibrio cholerae cells. We build a pseudo-atomic model of the complete sheath-tube assembly, which provides a mechanistic understanding of coupling sheath contraction with pushing and rotating the inner tube for efficient target membrane penetration. Our data further show that sheath contraction exposes a buried recognition domain to specifically trigger the disassembly and recycling of the T6SS sheath by the cognate ATP-dependent unfoldase ClpV.
Keywords:Bacterial Proteins, Cryoelectron Microscopy, Molecular Models, Spheroplasts, Type VI Secretion Systems, Vibrio cholerae
Source:Nature Microbiology
Publisher:Nature Publishing Group
Page Range:1507-1512
Date:November 2017
Official Publication:https://doi.org/10.1038/s41564-017-0020-7
PubMed:View item in PubMed

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