Lantibiotics are defined as peptide antibiotics containing the unusual amino 
acids mesolanthionine, 3-methyllanthionine, dehydroalanine, and dehydrobutyrine. 
They are synthesized by some gram-positive bacteria. Their inhibitory effect on 
certain other gram-positive bacteria is explained by detergent-like damage of 
cytoplasmic membranes. Prominent members of the lantibiotics are nisin of 
Lactococcus lactis, which can be used as a food preservative, subtilin of 
Bacillus subtilis, which is similar to nisin, and epidermin of Staphylococcus 
epidermidis, which is considered in the treatment of acne. Lantibiotics are 
ribosomally synthesized as prepeptides, which are posttranslationally modified. 
Genes probably encoding these biosynthetic enzymes and regulatory factors have 
been identified adjacent to the structural genes of the lantibiotics subtilin, 
nisin, and epidermin.