This family consists of several bundlin proteins from E. coli. Bundlin is a type IV pilin protein that is the only known structural component of enteropathogenic Escherichia coli bundle-forming pili (BFP). BFP play a role in virulence, antigenicity, autoaggregation, and localised adherence to epithelial cells [1]. These proteins contain an N-terminal methylation motif.

1: Molecular variation among type IV pilin (bfpA) genes from diverse enteropathogenic Escherichia coli strains. Blank TE, Zhong H, Bell AL, Whittam TS, Donnenberg MS; Infect Immun 2000;68:7028-7038. PMID:11083828