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Structure of the type VI secretion system contractile sheath

Item Type:Article
Title:Structure of the type VI secretion system contractile sheath
Creators Name:Kudryashev, M. and Wang, R.Y.R. and Brackmann, M. and Scherer, S. and Maier, T. and Baker, D. and DiMaio, F. and Stahlberg, H. and Egelman, E.H. and Basler, M.
Abstract:Bacteria use rapid contraction of a long sheath of the type VI secretion system (T6SS) to deliver effectors into a target cell. Here, we present an atomic-resolution structure of a native contracted Vibrio cholerae sheath determined by cryo-electron microscopy. The sheath subunits, composed of tightly interacting proteins VipA and VipB, assemble into a six-start helix. The helix is stabilized by a core domain assembled from four β strands donated by one VipA and two VipB molecules. The fold of inner and middle layers is conserved between T6SS and phage sheaths. However, the structure of the outer layer is distinct and suggests a mechanism of interaction of the bacterial sheath with an accessory ATPase, ClpV, that facilitates multiple rounds of effector delivery. Our results provide a mechanistic insight into assembly of contractile nanomachines that bacteria and phages use to translocate macromolecules across membranes.
Keywords:Amino Acid Sequence, Bacterial Proteins, Bacterial Secretion Systems, Cryoelectron Microscopy, Molecular Model, Molecular Sequence Data, Sequence Alignment, Vibrio cholerae
Publisher:Cell Press
Page Range:952-962
Date:26 February 2015
Official Publication:https://doi.org/10.1016/j.cell.2015.01.037
PubMed:View item in PubMed

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