7OKN

Structure of the outer-membrane core complex (inner ring) from a conjugative type IV secretion system

Summary for 7OKN

• Entry DOI: 10.2210/pdb7okn/pdb
• EMDB information: 12962
• Descriptor: TraB, Type IV conjugative transfer system lipoprotein TraV (2 entities in total)
• Functional Keywords: type iv secretion system, f plasmid, outer-membrane core complex, conjugation, membrane protein
• Biological source: Salmonella enterica; More
• Total number of polymer chains: 34
• Total formula weight: 1185422.78

Authors

Amin, H.,Ilangovan, A.,Costa, T.R.D. (deposition date: 2021-05-18, release date: 2021-12-01, Last modification date: 2024-10-23)

Primary citation

Amin, H.,Ilangovan, A.,Costa, T.R.D.
Architecture of the outer-membrane core complex from a conjugative type IV secretion system.
Nat Commun, 12:6834-6834, 2021

PubMed Abstract: Conjugation is one of the most important processes that bacteria utilize to spread antibiotic resistance genes among bacterial populations. Interbacterial DNA transfer requires a large double membrane-spanning nanomachine called the type 4 secretion system (T4SS) made up of the inner-membrane complex (IMC), the outer-membrane core complex (OMCC) and the conjugative pilus. The iconic F plasmid-encoded T4SS has been central in understanding conjugation for several decades, however atomic details of its structure are not known. Here, we report the structure of a complete conjugative OMCC encoded by the pED208 plasmid from E. coli, solved by cryo-electron microscopy at 3.3 Å resolution. This 2.1 MDa complex has a unique arrangement with two radial concentric rings, each having a different symmetry eventually contributing to remarkable differences in protein stoichiometry and flexibility in comparison to other OMCCs. Our structure suggests that F-OMCC is a highly dynamic complex, with implications for pilus extension and retraction during conjugation.

PubMed: 34824240
DOI: 10.1038/s41467-021-27178-8

Experimental method

ELECTRON MICROSCOPY (3.34 Å)