MATURATION PATHWAY OF NISIN AND OTHER LANTIBIOTICS - POSTTRANSLATIONALLY MODIFIED ANTIMICROBIAL PEPTIDES EXPORTED BY GRAM-POSITIVE BACTERIA

Lantibiotics form a family of highly modified peptides which are secre ted by several Gram-positive bacteria. They exhibit antimicrobial acti vity, mainly against other Gram-positive bacteria, by forming pores in the cellular membrane. These antimicrobial peptides are ribosomally s ynthesized and contain leader peptides which do not show the character istics of signal sequences. Several amino acid residues of the precurs or lantibiotic are enzymatically modified, whereafter secretion and pr ocessing of the leader peptide takes place, yielding the active antimi crobial substance. For several lantibiotics the gene clusters encoding biosynthetic enzymes, translocator proteins, self-protection proteins , processing enzymes and regulatory proteins have been identified. Thi s MicroReview describes the current knowledge about the biosynthetic, immunity and regulatory processes leading to lantibiotic production. M ost of the attention is focused on the lantibiotic nisin, which is pro duced by the food-grade bacterium Lactococcus lactis and is widely use d as a preservative in the food industry.