Lantibiotic

Lantibiotics are a class of antibacterial peptides that are produced by certain Gram-positive bacteria and fall under the broader category of ribosomally synthesized and post-translationally modified peptides (RiPPs). They are distinguished by the presence of unusual sulfur-containing amino acids, notably lanthionine and methyllanthionine, which arise from thioether cross-links that stabilize their structure and contribute to potency and stability.

Biosynthesis of lantibiotics begins with a ribosomal precursor that contains an N-terminal leader sequence. Post-translational modification enzymes remove the leader and introduce dehydration of serine and threonine residues to generate dehydroalanine and dehydrobutyrine. Cysteine residues then attack these dehydro residues to form lanthionine or methyllanthionine cross-links. The mature lantibiotic is produced after leader peptide removal. Biosynthetic systems are classified into several groups (commonly I and II) based on the enzymes involved, such as LanB/LanC or LanM.

The antimicrobial action of lantibiotics is typically directed against Gram-positive bacteria. Many inhibit cell wall synthesis by binding to lipid II, a key lipid carrier in peptidoglycan formation, while others can form pores in the bacterial membrane, leading to cell death. Their activity spectrum is often narrow but potent, and resistance can arise through various mechanisms, which has spurred ongoing research.

Applications include the use of some lantibiotics as food preservatives; nisin is the best-known example and is widely approved for use in foods in many regions. Beyond food preservation, lantibiotics are studied for therapeutic potential and as templates for engineering new antimicrobial agents.