Evidence for a role of NisT in transport of the lantibiotic nisin produced by Lactococcus lactis N8.

The biosynthesis, immunity and regulation of nisin, a lanthionine-containing antimicrobial peptide produced by Lactococcus lactis, is encoded by two gene clusters, nisA/ZBTCIPRK and nisFEG. The mutant strain LAC46 with a deletion in the translocator gene nisT could not secrete nisin but nisin activity was detected from cell lysates. The nisT mutation was complemented by a NisT-expression plasmid resulting in restored capacity to secrete nisin. These results demonstrate that NisT is the transport protein dedicated to translocate nisin and that dehydration and lanthionine formation in nisin maturation can occur independently of transport.