spacer Atomic model for the N-terminus of TraO fitted in the full-length structure of the bacterial pKM101 type IV secretion system core complex
Primary citation
Title Structure of a Bacterial Type Iv Secretion Core Complex at Subnanometre Resolution.
Authors Rivera-Calzada,; Fronzes,; Savva,; Chandran,; Lian,; Laeremans,; Pardon,; Steyaert,; Remaut,; Waksman,; Orlova,
Journal EMBO vol:32, pag:1195 (2013), Identifiers: PubMed ID (23511972)search DOI (10.1038/emboj.2013.58)
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.
MeSH terms
Other entries described in this publication 3zbj, 3zbi
Secondary citations
Title Structure of a Type Iv Secretion System Core Complex.
Authors Fronzes,; Schafer,; Wang,; Saibil,; Orlova,; Waksman,
Journal SCIENCEsearch vol:323, pag:266 (2009), Identifiers: PubMed ID (19131631)search DOI (10.1126/science.1166101)
Abstract Type IV secretion systems (T4SSs) are important virulence factors used by Gram-negative bacterial pathogens to inject effectors into host cells or to spread plasmids harboring antibiotic resistance genes. We report the 15 angstrom resolution cryo-electron microscopy structure of the core complex of a T4SS. The core complex is composed of three proteins, each present in 14 copies and forming a approximately 1.1-megadalton two-chambered, double membrane-spanning channel. The structure is double-walled, with each component apparently spanning a large part of the channel. The complex is open on the cytoplasmic side and constricted on the extracellular side. Overall, the T4SS core complex structure is different in both architecture and composition from the other known double membrane-spanning secretion system that has been structurally characterized.
MeSH terms Bacterial Outer Membrane Proteinssearch, Bacterial Proteinssearch, Cloningsearch, Molecularsearch, Cryoelectron Microscopysearch, Gram-Negative Bacteriasearch, Imagingsearch, Three-Dimensionalsearch, Modelssearch, Molecularsearch, Multiprotein Complexessearch, Plasmidssearch, Protein Conformationsearch, Protein Structuresearch, Quaternarysearch, Virulence Factorssearch