Structure of CfaA Suggests a New Family of Chaperones Essential for Assembly of Class 5 Fimbriae

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Bacterial infection begins with microbial adhesion to host cells. For gram-negative bacteria, adhesion is often mediated by pili, proteinaceous polymers that protrude from the bacterial surface and recognize host receptors. During assembly, each pilus protein subunit is assisted in folding by a chaperone that shuttles the subunit to an outer membrane usher complex, which serves as assembly platform. There, the chaperone transfers its subunit cargo into the growing pilus polymer, which protrudes out the usher pore. Here, we present the crystal structure of CfaA, the chaperone protein of the CFA/I pilus. The CFA/I pilus is the archetypal colonization factor (CF) for enterotoxigenic Escherichia coli, a major cause of life-threatening, dehydrating diarrhea in young children of low-income countries and in travelers to these regions. This structure reveals unique features that allow us to define a new class of chaperones that assist pilus assembly in bacteria. Probing these unique features with site-direct mutagenesis, we were able to gain new insight into the mechanism of pilus assembly.

Vyšlo v časopise: Structure of CfaA Suggests a New Family of Chaperones Essential for Assembly of Class 5 Fimbriae. PLoS Pathog 10(8): e32767. doi:10.1371/journal.ppat.1004316
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.ppat.1004316

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