Isopeptide bonds of the major pilin protein BcpA influence pilus structure and bundle formation on the surface of Bacillus cereus.

ABSTRACT: Bacillus cereus strains elaborate pili on their surface using a mechanism of sortase-mediated cross-linking of major and minor pilus components. Here we used a combination of electron microscopy and atomic force microscopy to visualize these structures. Pili occur as single, double or higher order assemblies of filaments formed from monomers of the major pilin, BcpA, capped by the minor pilin, BcpB. Previous studies demonstrated that within assembled pili, four domains of BcpA - CNA(1), CNA(2), XNA and CNA(3) - each acquire intramolecular lysine-asparagine isopeptide bonds formed via catalytic glutamic acid or aspartic acid residues. Here we showed that mutants unable to form the intramolecular isopeptide bonds in the CNA(2) or CNA(3) domains retain the ability to form pilus bundles. A mut

SUBMITTER: Hendrickx AP 

PROVIDER: S-EPMC3538817 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature