lantibiòtics

Lantibiotics, or lantibiotics, are a class of peptide antibiotics produced by certain Gram-positive bacteria. They are ribosomally synthesized and post-translationally modified peptides (RiPPs) that contain unusual amino acids such as lanthionine and methyllanthionine, formed through dehydration and lanthionine ring formation.

The characteristic structural feature of lantibiotics is the presence of lanthionine rings created when serine or threonine residues are chemically modified and cross-linked to cysteines. Biosynthesis typically involves a precursor peptide (LanA), modification enzymes (LanB and LanC), and a dedicated transporter for export and processing. Immunity genes within the clusters help the producing organism tolerate the antibiotic.

Most lantibiotics act primarily against Gram-positive bacteria. Their mechanisms commonly involve binding to lipid II, a crucial precursor in peptidoglycan synthesis, which can inhibit cell wall formation and/or cause pore formation in the cell membrane, leading to cell death. Their activity against Gram-negative bacteria is usually limited by the outer membrane barrier.

Notable examples include nisin, subtilin, epidermin, gallidermin, and lacticins such as lacticin 481 and lacticin 3147 (a two-component lantibiotic). Nisin is widely used as a food preservative and has regulatory approvals in many regions, including some GRAS status in the United States and approvals in the European Union.

Applications and research: lantibiotics are explored for food preservation and as potential therapeutic agents, including combination therapies to address resistance. Development challenges include improving spectrum and potency, avoiding resistance, manufacturing complexity, and ensuring safety in clinical or food contexts.