Lantibiotics--unusually modified bacteriocin-like peptides from gram-positive bacteria.

Lantibiotics are antibacterial peptides frequently produced by Gram-positive bacteria. They are distinguished by unique structural properties unprecedented so far in peptide chemistry. The most striking feature is the occurrence of intramolecular rings introduced by the thioether amino acids lanthionine and 3-methyllantionine. Additional usual amino acids such as didehydroalanine and didehydrobutyrine are found. Lantibiotics are produced from ribosomally synthesized prepeptides and the unusual amino acids are formed by post-translational modifications. This review summarizes the current knowledge on the biosynthetic mechanisms and enzymes taking part in biosynthesis, on the primary and spatial structures of the active peptides and the correlation between structural aspects and the antibacterial activity. Furthermore, the mode of action of type-A lantibiotics and the immunity phenomenon are described, and an outlook for future research and potential applications is given.