A Disulfide Bond-forming Machine Is Linked to the Sortase-mediated Pilus Assembly Pathway in the Gram-positive Bacterium Actinomyces oris.

ABSTRACT: Export of cell surface pilins in Gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. Here, we present physiological studies to demonstrate that the FimA pilin of Actinomyces oris contains two disulfide bonds. Alanine substitution of cysteine residues forming the C-terminal disulfide bridge abrogates pilus assembly, in turn eliminating biofilm formation and polymicrobial interaction. Transposon mutagenesis of A. oris yielded a mutant defective in adherence to Streptococcus oralis, and revealed the essential role of a vitamin K epoxide reductase (VKOR) gene in pilus assembly. Targeted deletion of vkor results in the same defects, which are rescued by ectopic express

SUBMITTER: Reardon-Robinson ME 

PROVIDER: S-EPMC4571867 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature