A novel lantibiotic, nukacin ISK-1, of Staphylococcus warneri ISK-1: Cloning of the structural gene and identification of the structure

Staphylococcus warneri ISK-1, which we had previously reported as Pediococc us sp, ISK-1, produces a novel bacteriocin, nukacin ISK-1. Edman degradatio n of the chemically reduced nukacin ISK-1 produced a sequence of 27 amino a cids, 7 of which were unidentified. Using single-specific-primer-PCR produc t as a probe, a 3.6-kb HindIII fragment containing the nukacin ISK-1 struct ural gene (nukA) was cloned and sequenced. The deduced amino acid sequence of nukacin ISK-1 had 57 amino acids, including a 30-amino acid leader regio n. The propeptide sequence showed significant similarity to those of lactic in-481 type lantibiotics. In the region upstream of nukA, a part of a long open reading frame (ORF), designated as nukM, encoding a putative modificat ion enzyme was oriented in the opposite direction. In the region downstream of nukA, ORF1 was found in which the sequence of the putative translationa l product was similar to various response regulatory proteins.