Handover mechanism of the growing pilus by the bacterial outer-membrane usher FimD.

ABSTRACT: Pathogenic bacteria such as Escherichia coli assemble surface structures termed pili, or fimbriae, to mediate binding to host-cell receptors¹. Type 1 pili are assembled via the conserved chaperone-usher pathway^2-5. The outer-membrane usher FimD recruits pilus subunits bound by the chaperone FimC via the periplasmic N-terminal domain of the usher. Subunit translocation through the β-barrel channel of the usher occurs at the two C-terminal domains (which we label CTD1 and CTD2) of this protein. How the chaperone-subunit complex bound to the N-terminal domain is handed over to the C-terminal domains, as well as the timing of subunit polymerization into the growing pilus, have previously been unclear. Here we use cryo-electron microscopy to capture a pilus assembly interm

SUBMITTER: Du M 

PROVIDER: S-EPMC6309448 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature