3JQO

Crystal structure of the outer membrane complex of a type IV secretion system

Summary for 3JQO

• Entry DOI: 10.2210/pdb3jqo/pdb
• Related: 2BHV 2OFQ
• EMDB information: 5031 5034
• Descriptor: TraF protein, TraO protein, TraN protein, ... (6 entities in total)
• Functional Keywords: helical outer membrane tm, outer membrane protein complex, transport protein
• Biological source: Escherichia coli; More
• Total number of polymer chains: 42
• Total formula weight: 606122.94

Authors

Chandran, V.,Fronzes, R.,Duquerroy, S.,Cronin, N.,Navaza, J.,Waksman, G. (deposition date: 2009-09-07, release date: 2009-12-01, Last modification date: 2024-10-16)

Primary citation

Chandran, V.,Fronzes, R.,Duquerroy, S.,Cronin, N.,Navaza, J.,Waksman, G.
Structure of the outer membrane complex of a type IV secretion system
Nature, 462:1011-1015, 2009

PubMed Abstract: Type IV secretion systems are secretion nanomachines spanning the two membranes of Gram-negative bacteria. Three proteins, VirB7, VirB9 and VirB10, assemble into a 1.05 megadalton (MDa) core spanning the inner and outer membranes. This core consists of 14 copies of each of the proteins and forms two layers, the I and O layers, inserting in the inner and outer membrane, respectively. Here we present the crystal structure of a approximately 0.6 MDa outer-membrane complex containing the entire O layer. This structure is the largest determined for an outer-membrane channel and is unprecedented in being composed of three proteins. Unexpectedly, this structure identifies VirB10 as the outer-membrane channel with a unique hydrophobic double-helical transmembrane region. This structure establishes VirB10 as the only known protein crossing both membranes of Gram-negative bacteria. Comparison of the cryo-electron microscopy (cryo-EM) and crystallographic structures points to conformational changes regulating channel opening and closing.

PubMed: 19946264
DOI: 10.1038/nature08588

Experimental method

X-RAY DIFFRACTION (2.6 Å)