Characterization and Mutational Analysis of a Two-Polypeptide Bacteriocin Produced by Citrus Iyo-Derived Lactobacillus brevis 174A

Noda Masafumi

Miyauchi Rumi

Danshiitsoodol Narandalai

Higashikawa Fumiko

Kumagai Takanori

Matoba Yasuyuki

Sugiyama Masanori

Biological and Pharmaceutical Bulletin

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.

bacteriocin

Lactobacillus brevis

actic acid bacteria

eng

The Pharmaceutical Society of Japan

Copyright (c) 2015 The Pharmaceutical Society of Japan

[ISSN] 0918-6158

[ISSN] 1347-5215

[NCID] AA10885497

[DOI] 10.1248/bpb.b15-00505

[DOI] https://doi.org/10.1248/bpb.b15-00505

[PMID] 26632181