Structure of a bacterial type IV secretion core complex at subnanometre resolution.

TitleStructure of a bacterial type IV secretion core complex at subnanometre resolution.
Publication TypeJournal Article
Year of Publication2013
AuthorsRivera-Calzada, A., R. Fronzes, C. G. Savva, V. Chandran, P. W. Lian, T. Laeremans, E. Pardon, J. Steyaert, H. Remaut, G. Waksman, and E. V. Orlova
JournalEMBO J
Volume32
Issue8
Pagination1195-204
Date Published2013 Apr 17
Type of Articleem
ISSN1460-2075
KeywordsAgrobacterium tumefaciens, Bacterial Secretion Systems, Cryoelectron Microscopy, Membrane Transport Proteins, Models, Molecular, Multiprotein Complexes, Protein Conformation
Abstract

Type IV secretion (T4S) systems are able to transport DNAs and/or proteins through the membranes of bacteria. They form large multiprotein complexes consisting of 12 proteins termed VirB1-11 and VirD4. VirB7, 9 and 10 assemble into a 1.07 MegaDalton membrane-spanning core complex (CC), around which all other components assemble. This complex is made of two parts, the O-layer inserted in the outer membrane and the I-layer inserted in the inner membrane. While the structure of the O-layer has been solved by X-ray crystallography, there is no detailed structural information on the I-layer. Using high-resolution cryo-electron microscopy and molecular modelling combined with biochemical approaches, we determined the I-layer structure and located its various components in the electron density. Our results provide new structural insights on the CC, from which the essential features of T4S system mechanisms can be derived.

DOI10.1038/emboj.2013.58
Alternate JournalEMBO J.
PubMed ID23511972
PubMed Central IDPMC3630358
Grant List082227 / / Wellcome Trust / United Kingdom
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