Typically cleaves a -Gly┼Phe- bond to release an N-terminal, basic peptide of 5-8 residues from type IV prepilin, and then N-methylates the new N-terminal amino group, the methyl donor being S-adenosyl-L-methionine
Many species of bacteria carry pili on their cell surfaces. These are virulence determinants in pathogenic strains, and are assembled biosynthetically from type IV prepilin subunits. Before assembly, the prepilin molecules require proteolytic processing, which is done by the prepilin peptidase. Prepilin peptidase and its homologues play a central role not only in type IV pilus biogenesis but also in transport of macromolecules across cell membranes. Although both peptide-bond hydrolysis and N-methylation are catalysed by the same molecule, the methylation can be inhibited without affecting peptidase activity, and it is believed that the enzyme has two separate catalytic sites. Type example of peptidase family A24.