The biosynthesis and mode of action of a class of compounds called lantibiotics, a peptide with antibacterial activity against multi-drug resistant bacteria as well as food-borne pathogens like Listeria monocytogenes and Clostridium botulinum is described. These peptide-derived compounds are especially interesting because they could be used as bactericidal agents for an extended period with very little bacterial resistance and the mechanism by which lantibiotics are produced in bacteria could be used to develop new and more potent analogs.