Second order rate constants of donor-strand exchange reveal individual amino acid residues important in determining the subunit specificity of pilus biogenesis.

ABSTRACT: P pili are hair-like adhesive structures that are assembled on the outer membrane (OM) of uropathogenic Escherichia coli by the chaperone-usher pathway. In this pathway, chaperone-subunit complexes are formed in the periplasm and targeted to an OM assembly platform, the usher. Pilus subunits display a large groove caused by a missing β-strand which, in the chaperone-subunit complex, is provided by the chaperone. At the usher, pilus subunits are assembled in a mechanism termed "donor-strand exchange (DSE)" whereby the β-strand provided by the chaperone is exchanged by the incoming subunit's N-terminal extension (Nte). This occurs in a zip-in-zip-out fashion, starting with a defined residue, P5, in the Nte inserting into a defined site in the groove, the P5 pocket. Here, electrospray ionizat

SUBMITTER: Leney AC 

PROVIDER: S-EPMC3252035 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature