title: Characterization and Mutational Analysis of a Two-Polypeptide Bacteriocin Produced by Citrus Iyo-Derived Lactobacillus brevis 174A.
abstract: In the present study, we isolated a lactic acid bacterium (LAB) from a citrus iyo fruit and identified it as Lactobacillus brevis. This plant-derived LAB strain, designated 174A, produces bacteriocin consisting of two polypeptides designated brevicin 174A-β and 174A-γ. Although each polypeptide itself displays antibacterial activity, the ability is enhanced 100 fold by mixing both polypeptides at a 1 : 1 ratio. Significantly, brevicin 174A inhibits even the growth of several pathogenic bacteria that are more resistant to a lantibiotic bacteriocin, nisin A, which is commonly utilized as a preservative added to foodstuffs. Structural analysis of the 174A bacteriocin using a program that predicts secondary structure suggests that both component polypeptides have a positively charged N-terminal region, as well as two cysteine residues in both the N- and C-terminals. Judging from a mutational analysis of the antibacterial polypeptides, these unique amino acid sequences of 174A-β might be important for the expression of the synergistic activity that occurs in the presence of the two polypeptides combined.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Graduate School of Biomedical Sciences, Hiroshima University.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Noda
authors.forename: Rumi
authors.initials: R
authors.lastname: Miyauchi
authors.forename: Narandalai
authors.initials: N
authors.lastname: Danshiitsoodol
authors.forename: Fumiko
authors.initials: F
authors.lastname: Higashikawa
authors.forename: Takanori
authors.initials: T
authors.lastname: Kumagai
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Matoba
authors.forename: Masanori
authors.initials: M
authors.lastname: Sugiyama
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000494:pharmacology; D001430:Bacteriocins / Q000032:analysis* / Q000494:pharmacology; D002957:Citrus / Q000382:microbiology*; D004252:DNA Mutational Analysis; D004357:Drug Synergism; D005638:Fruit / Q000382:microbiology*; D005798:Genes, Bacterial; D019344:Lactic Acid; D052196:Levilactobacillus brevis / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000032:analysis* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D010455:Peptides; C000610769:brevicin 174A, Lactobacillus brevis; D019344:Lactic Acid