Printed in U.S.A. Structure, Organization, and Expression of the k t Gene for Lacticin 481, a Novel Lantibiotic Produced by l;uctococcus luctis*

The structural gene for the lactococcal lantibiotic lacticin 481 (k t) has been identified and cloned using a degenerated 20-mer DNA oligonucleotide based on the amino-terminal 7 amino acid residues of the puri-fied protein. The transcription of the Ict gene was analyzed, and its promoter was mapped. DNA sequence analysis of the Ict gene revealed an open reading frame encoding a peptide of 51 amino acids. Comparison of its deduced amino acid sequence with the amino-ter-mind sequence and the amino acid composition of lac-ticin 481 indicates that the 61-residue peptide is pre-lacticin 481, containing a 27-residue carboxyl-termi-nal propeptide and a 24-residue amino-terminal leader peptide which lacks the properties of a typical signal sequence and which is significantly different from th