Function of Lactococcus lactis nisin immunity genes nisI and nisFEG after coordinated expression in the surrogate host Bacillus subtilis.
Nisin-producing Lactococcus lactis strains show a high degree of resistance to the action of nisin, which is based upon expression of the self-protection (immunity) genes nisI, nisF, nisE, and nisG. Different combinations of nisin immunity genes were integrated into the chromosome of a nisin-sensitive Bacillus subtilis host strain under the control of an inducible promoter. For the recipient strain, the highest level of acquired nisin tolerance was achieved after coordinated expression of all four nisin immunity genes. But either the lipoprotein NisI or the ABC transporter-homologous system NisFEG, respectively, were also able to protect the Bacillus host cells. The acquired immunity was specific to nisin and provided no tolerance to subtilin, a closely related lantibiotic. Quantitative in vivo peptide release assays demonstrated that NisFEG diminished the quantity of cell-associated nisin, providing evidence that one role of NisFEG is to transport nisin from the membrane into the extracellular space. NisI solubilized from B. subtilis membrane vesicles and recombinant hexahistidine-tagged NisI from Escherichia coli interacted specifically with nisin and not with subtilin. This suggests a function of NisI as a nisin-intercepting protein.
Stein
Torsten
T
Institut für Mikrobiologie, Johann Wolfgang Goethe-Universität, D-60439 Frankfurt am Main, Germany.
Heinzmann
Stefan
S
Solovieva
Irina
I
Entian
Karl-Dieter
KD
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001692:Biological Transport / Q000502:physiology; D002458:Cell Fractionation; D024881:Drug Resistance, Bacterial; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D013294:Lactococcus lactis / Q000187:drug effects / Q000235:genetics* / Q000276:immunology; D008074:Lipoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D008565:Membrane Proteins; D005810:Multigene Family; D009561:Nisin / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D009876:Operon; D011401:Promoter Regions, Genetic; D020860:Subtilisin / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D014158:Transcription, Genetic
D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008074:Lipoproteins; D008565:Membrane Proteins; C093080:NisE protein, Lactococcus lactis; C093081:NisF protein, Lactococcus lactis; C094909:NisI protein, Lactococcus lactis; C093082:nisG protein, Lactococcus lactis; D009561:Nisin; D020860:Subtilisin