Membrane-associated proteins encoded by the nisin gene cluster may function as a receptor for the lantibiotic carnocin UI49.
Carnocin UI49, a lantibiotic produced by Carnobacterium piscicola shows bactericidal activity against many lactic acid bacteria. This paper describes the results of a study on the mode of action of carnocin UI49. It has previously been observed that nisin-producing Lactococcus lactis subsp. lactis strains are at least 10-fold more sensitive to carnocin UI49 relative to other lactic acid bacteria. Addition of carnocin UI49 to cells of L. lactis subsp. lactis NZ9700 resulted in a dissipation of the membrane potential and a rapid hydrolysis of internal ATP. These results suggest that carnocin UI49 may act at the cytoplasmic membrane. The correlation between production of and/or immunity to nisin and sensitivity to carnocin of L. lactis subsp. lactis strains was further investigated. Several transformed L. lactis subsp. lactis strains carrying a fragment of the nisin gene cluster were tested for their sensitivity to carnocin UI49 and their immunity to nisin. The results suggest that NisP, which is one of the membrane-associated proteins involved in the production of nisin acts as receptor for carnocin UI49. This may facilitate the binding and/or insertion of carnocin UI49 into the cytoplasmic membrane thus increasing its bactericidal activity. Lantibiotic-producing and non-producing mutants of Staphylococcus epidermidis and Lactobacillus sake did not show a difference in sensitivity to carnocin UI49. The proposed receptor-mediated action of carnocin UI49 at the cytoplasmic membrane therefore seems to be specific for the nisin-producing strains.
Stoffels
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Science Institute, University of Iceland, Reykjavik.
Guthmundsdóttir
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Abee
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D000255:Adenosine Triphosphate / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001430:Bacteriocins; D002352:Carrier Proteins / Q000235:genetics; D002463:Cell Membrane Permeability / Q000187:drug effects; D004251:DNA Transposable Elements / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D005798:Genes, Bacterial; D013294:Lactococcus lactis / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008954:Models, Biological; D005810:Multigene Family; D009561:Nisin / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D010455:Peptides; D013045:Species Specificity; D013381:Subtilisins / Q000235:genetics* / Q000378:metabolism; D013696:Temperature
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001430:Bacteriocins; D002352:Carrier Proteins; D004251:DNA Transposable Elements; D008565:Membrane Proteins; D010455:Peptides; C089233:carnocin UI49; D009561:Nisin; D000255:Adenosine Triphosphate; C080937:NisP protein, Lactococcus lactis; D013381:Subtilisins