Lacticin 481 is a class II lantibiotic and is derived from a gene-encoded precursor peptide, which consists of an N-terminal leader peptide and a C-terminal modifiable core peptide.Lanthipeptides are characterized by the presence of lanthionine (Lan) and/or methyllanthionine (MeLan) ring structures. These are formed in a two-step process. First, dehydration of serine (S) and threonine (T) residues results in dehydroalanine (Dha) and dehydrobutyrine (Dhb). The intramolecular thioether cross-links are then formed by stereoselective 1,4-addition of cysteine thiol groups to the dehydroamino acids. (Me)Lan residues contribute to the stability of the bioactive conformation of lantibiotics and can provide protection against proteases. After these modifications, the peptide is exported, followed by cleavage of the leader by a protease, resulting in the mature, active peptide.
