lacticin

Lacticin is a family of bacteriocins produced by lactic acid bacteria, most notably Lactococcus lactis. These compounds belong to the lantibiotics, a class of ribosomally synthesized and post-translationally modified peptides (RiPPs). Lacticins are typically small, heat-stable peptides that undergo enzymatic dehydration and lanthionine bridge formation before export from the producer cell. Notable members include lacticin 481 and lacticin 3147; the latter is a two-component lantibiotic composed of two synergistic peptide components.

Gene clusters encoding lacticins contain genes for the precursor peptide (lanA), modification enzymes (lanB/LanC or lanM), immunity factors, and a dedicated transporter. Lacticin production is usually accompanied by self-immunity to prevent the producer from being killed by its own antibiotic. Regulation is tied to growth conditions and the presence of target bacteria, with production often higher in environments rich in nutrients.

Antimicrobial activity is largely directed against Gram-positive bacteria, including several foodborne pathogens. The mechanism often involves binding to lipid II, an essential cell wall precursor, and forming pores in the cytoplasmic membrane, which inhibits cell wall synthesis and disrupts membrane integrity. While activity against Gram-negative bacteria is limited due to outer membrane barriers, combinations and formulation strategies can enhance efficacy in some contexts.

Applications include use as natural food preservatives and biocontrol agents in dairy and meat products, and as lead compounds for developing new antimicrobials. Research continues to optimize production, stability, and spectrum, as well as to understand structure–activity relationships and potential resistance mechanisms.