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Structure of the GspK-GspI-GspJ complex from the enterotoxigenic Escherichia coli type 2 secretion system.

Research paper by Konstantin V KV Korotkov, Wim G J WG Hol

Indexed on: 29 Apr '08Published on: 29 Apr '08Published in: Nature Structural and Molecular Biology



Abstract

Gram-negative bacteria translocate various proteins including virulence factors across their outer membrane via type 2 secretion systems (T2SSs). T2SSs are thought to contain a pseudopilus, a subcomplex formed by one major and several minor pseudopilins. We report the crystal structure of the complex formed by three minor pseudopilins from enterotoxigenic Escherichia coli. The GspK-GspI-GspJ complex has quasihelical characteristics and an architecture consistent with a localization at the pseudopilus tip. The alpha-domain of GspK has a previously unobserved fold with an unexpected dinuclear metal binding site. The area surrounding its disulfide bridge is conserved and might interact with other T2SS components or with secreted proteins.