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IpaB-IpgC interaction defines binding motif for type III secretion translocator.

ABSTRACT: The delivery of virulence factors into host cells through type III secretion systems is essential for enterobacterial pathogenesis. Molecular chaperones bind specifically to virulence factors in the bacterial cytosol before secretion. Invasion plasmid gene C (IpgC) is a chaperone that binds 2 essential virulence factors of Shigella: invasion plasmid antigens (Ipa) B and C. Here, we report the crystal structure of IpgC alone and in complex with the chaperone binding domain (CBD) of IpaB. The chaperone captures the CBD in an extended conformation that is stabilized by conserved residues lining the cleft. Analysis of the cocrystal structure reveals a sequence motif that is functional in the IpaB translocator class from different bacteria as determined by isothermal titration calorimetry. Our results show how translocators are chaperoned and may allow the design of inhibitors of enterobacterial diseases.

SUBMITTER: Lunelli M

PROVIDER: S-EPMC2701029 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature

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IpaB-IpgC interaction defines binding motif for type III secretion translocator.

Lunelli Michele M Lokareddy Ravi Kumar RK Zychlinsky Arturo A Kolbe Michael M

Proceedings of the National Academy of Sciences of the United States of America 20090528 24

The delivery of virulence factors into host cells through type III secretion systems is essential for enterobacterial pathogenesis. Molecular chaperones bind specifically to virulence factors in the bacterial cytosol before secretion. Invasion plasmid gene C (IpgC) is a chaperone that binds 2 essential virulence factors of Shigella: invasion plasmid antigens (Ipa) B and C. Here, we report the crystal structure of IpgC alone and in complex with the chaperone binding domain (CBD) of IpaB. The chap ...[more]

PMID: 19478065

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