Lactococcin Q, a novel two-peptide bacteriocin produced by Lactococcus lactis QU 4

Takeshi Zendo, Shoko Koga, Yasushi Shigeri, Jiro Nakayama, Kenji Sonomoto

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82 Citations (Scopus)


A bacteriocin-producing strain, Lactococcus lactis QU 4, was isolated from corn. The bacteriocin, termed lactococcin Q, showed antibacterial activity only against L. lactis strains among a wide range of gram-positive indicator strains tested. Lactococcin Q was purified by acetone precipitation, cation exchange chromatography, and reverse-phase chromatography. Lactococcin Q consisted of two peptides, α and β, whose molecular masses were determined to be 4,260.43 Da and 4,018.36 Da, respectively. Amino acid and DNA sequencing analyses revealed that lactococcin Q was a novel two-peptide bacteriocin, homologous to lactococcin G. Comparative study using chemically synthesized lactococcin Q (Qα plus Qβ) and lactococcin G (Gα plus Gβ) clarified that hybrid combinations (Qα plus Gβ and Gα plus Qβ) as well as original combinations showed antibacterial activity, although each single peptide showed no significant activity. These four pairs of lactococcin peptides acted synergistically at a 1:1 molar ratio and exhibited identical antibacterial spectra but differed in MIC. The MIC of Qα plus Gβ was 32 times higher than that of Qα plus Qβ, suggesting that the difference in β peptides was important for the intensity of antibacterial activity.

Original languageEnglish
Pages (from-to)3383-3389
Number of pages7
JournalApplied and environmental microbiology
Issue number5
Publication statusPublished - May 2006

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology


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