title: Molecular and genetic characterization of a novel nisin variant produced by Streptococcus uberis.
abstract: Streptococcus uberis is one of the principal causative agents of bovine mastitis. In this study, we report that S. uberis strain 42 produces a lantibiotic, nisin U, which is 78% identical (82% similar) to nisin A from Lactococcus lactis. The 15.6-kb nisin U locus comprises 11 open reading frames, similar in putative functionality but differing in arrangement from that of the nisin A biosynthetic cluster. The nisin U producer strain exhibits specific resistance (immunity) to nisin U and cross-resistance to nisin A, a finding consistent with the 55% sequence similarity of their respective immunity peptides. Homologues of the nisin U structural gene were identified in several additional S. uberis strains, and in each case cross-protective immunity was expressed to nisin A and to the other producers of nisin U and its variants. To our knowledge, this is the first report both of characterization of a bacteriocin by S. uberis, as well as of a member of the nisin family of peptides in a species other than L. lactis.
authors.affiliation: Department of Microbiology and Immunology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Wirawan
authors.forename: Nikolai A
authors.initials: NA
authors.lastname: Klesse
authors.forename: Ralph W
authors.initials: RW
authors.lastname: Jack
authors.forename: John R
authors.initials: JR
authors.lastname: Tagg
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D005798:Genes, Bacterial; D014644:Genetic Variation; D008414:Mastitis, Bovine / Q000382:microbiology / Q000517:prevention & control; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009561:Nisin / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics* / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D013291:Streptococcus / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity
chemical_list: D004269:DNA, Bacterial; D009561:Nisin