Mode of Action of Lactococcin B, a Thiol-Activated Bacteriocin from Lactococcus lactis

K. Venema, T. Abee, A.J. Haandrikman, K.J. Leenhouts, J. Kok, W.N. Konings, G. Venema

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Abstract

Lactococcin B (LcnB) is a small, hydrophobic, positively charged bacteriocin produced by Lactococcus lactis subsp. cremoris 9B4. Purified LcnB has a bactericidal effect on sensitive L. lactis cells by dissipating the proton motive force and causing leakage of intracellular substrates. The activity of LcnB depends on the reduced state of the Cys-24 residue. Uptake and efflux studies of different solutes suggest that LcnB forms pores in the cytoplasmic membrane of sensitive L. lactis cells in the absence of a proton motive force. At low concentrations of LcnB, efflux of those ions and amino acids which are taken up by proton motive force-driven systems was observed. However, a 150-fold higher LcnB concentration was required for efflux of glutamate, previously taken up via a unidirectional ATP-driven transport system. Strains carrying the genetic information for the immunity protein against LcnB were not affected by LcnB. The proton motive force of immune cells was not dissipated, and no leakage of intracellular substrates could be detected.

Original languageEnglish
Pages (from-to)1041-1048
Number of pages8
JournalApplied and environmental microbiology
Volume59
Issue number4
Publication statusPublished - Apr-1993

Keywords

  • PEPTIDE ANTIBIOTIC NISIN
  • ARTIFICIAL MEMBRANE-VESICLES
  • STREPTOCOCCUS-LACTIS
  • ANTIMICROBIAL PEPTIDES
  • TRANSPORT-SYSTEM
  • LIPID-MEMBRANES
  • ACID TRANSPORT
  • SUBSP CREMORIS
  • HELVETICIN-J
  • PLASMID

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