Type IIa bacteriocins, which are isolated from lactic acid bacteria that are useful for food preservation, are potent antimicrobial peptides with considerable potential as therapeutic agents for gastrointestinal infections in mam-mals. They are ribosomally synthesized as precursors with an N-terminal leader, typically 18–24 amino acid residues in length, which is cleaved during export from the produ-cing cell. We have chemically synthesized the full precursor of carnobacteriocin B2, precarnobacteriocin (preCbnB2), which has a C-terminal amide rather than a carboxyl, and also produced preCbnB2(1–64), .
