Structural insights into the assembly of the type III secretion needle complex.

ABSTRACT: Type III secretion systems (TTSSs) mediate translocation of virulence factors into host cells. We report the 17-angstrom resolution structures of a central component of Salmonella typhimurium TTSS, the needle complex, and its assembly precursor, the bacterial envelope-anchored base. Both the base and the fully assembled needle complex adopted multiple oligomeric states in vivo, and needle assembly was accompanied by recruitment of the protein PrgJ as a structural component of the base. Moreover, conformational changes during needle assembly created scaffolds for anchoring both PrgJ and the needle substructure and may provide the basis for substrate-specificity switching during type III secretion.

SUBMITTER: Marlovits TC 

PROVIDER: S-EPMC1459965 | biostudies-literature | 2004 Nov

REPOSITORIES: biostudies-literature