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Structural insights into the Type II secretion nanomachine.

ABSTRACT: The Type II secretion nanomachine transports folded proteins across the outer membrane of Gram-negative bacteria. Recent X-ray crystallography, electron microscopy, and molecular modeling studies provide structural insights into three functionally and spatially connected units of this nanomachine: the cytoplasmic and inner membrane energy-harvesting complex, the periplasmic helical pseudopilus, and the outer membrane secretin. Key advances include cryo-EM reconstruction of the secretin and demonstration that it interacts with both secreted substrates and a crucial transmembrane clamp protein, plus a biochemical and structural explanation of the role of low-abundance pseudopilins in initiating pseudopilus growth. Combining structures and protein interactions, we synthesize a 3D view of the complete complex consistent with a stepwise pathway in which secretin oligomerization defines sites of nanomachine biogenesis.

SUBMITTER: McLaughlin LS

PROVIDER: S-EPMC3341957 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature

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Structural insights into the Type II secretion nanomachine.

McLaughlin Lorraine S LS Haft Rembrandt J F RJ Forest Katrina T KT

Current opinion in structural biology 20120316 2

The Type II secretion nanomachine transports folded proteins across the outer membrane of Gram-negative bacteria. Recent X-ray crystallography, electron microscopy, and molecular modeling studies provide structural insights into three functionally and spatially connected units of this nanomachine: the cytoplasmic and inner membrane energy-harvesting complex, the periplasmic helical pseudopilus, and the outer membrane secretin. Key advances include cryo-EM reconstruction of the secretin and demon ...[more]

PMID: 22425326

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