title: Identification and characterization of lactocyclicin Q, a novel cyclic bacteriocin produced by Lactococcus sp. strain QU 12.
abstract: Lactococcus sp. strain QU 12, which was isolated from cheese, produced a novel cyclic bacteriocin termed lactocyclicin Q. By using cation-exchange chromatography, hydrophobic interaction chromatography, and reverse-phase high-performance liquid chromatography, lactocyclicin Q was purified from culture supernatant, and its molecular mass was determined to be 6,062.8 Da by mass spectrometry. Lactocyclicin Q has been characterized by its unique antimicrobial spectrum, high level of protease resistance, and heat stability compared to other reported bacteriocins of lactic acid bacteria. The amino acid sequence of lactocyclicin Q was determined chemically, and this compound is composed of 61 amino acid residues that have a cyclic structure with linkage between the N and C termini by a peptide bond. It showed no homology to any other antimicrobial peptide, including cyclic bacteriocins. On the basis of the amino acid sequences obtained, the sequence of the gene encoding the prepeptide lactocyclicin Q was obtained. This is the first report of a cyclic bacteriocin purified from a strain belonging to the genus Lactococcus.
authors.affiliation: Laboratory of Microbial Technology, Division of Microbial Science and Technology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Naruhiko
authors.initials: N
authors.lastname: Sawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Zendo
authors.forename: Junko
authors.initials: J
authors.lastname: Kiyofuji
authors.forename: Koji
authors.initials: K
authors.lastname: Fujita
authors.forename: Kohei
authors.initials: K
authors.lastname: Himeno
authors.forename: Jiro
authors.initials: J
authors.lastname: Nakayama
authors.forename: Kenji
authors.initials: K
authors.lastname: Sonomoto
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000187:drug effects*; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000494:pharmacology*; D001483:Base Sequence; D002852:Chromatography, Ion Exchange; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D006358:Hot Temperature; D017045:Lactococcus / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D001430:Bacteriocins; D004269:DNA, Bacterial; D010447:Peptide Hydrolases