Open AccessLipid‐free NisI: interaction with nisin and contribution to nisin immunity via secretion
Author(s) -
Takala Timo M.,
Koponen Olli,
Qiao Mingqiang,
Saris Per E.J.
Publication year - 2004
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2004.tb09693.x
Subject(s) - nisin , lactococcus lactis , secretion , lipid ii , atp binding cassette transporter , lantibiotics , bacteriocin , signal peptide , immunity , biochemistry , cytoplasm , biology , microbiology and biotechnology , transporter , chemistry , peptide sequence , bacteria , biosynthesis , immune system , gene , antimicrobial , immunology , genetics , lactic acid
Nisin‐producing Lactococcus lactis cells protect their own cytoplasmic membrane by specific immunity proteins, NisF/E/G and NisI, a transporter complex and a lipoprotein, respectively. A portion of NisI is secreted to the medium in a lipid‐free form (LF‐NisI). Here, kinetics of the interaction between nisin and LF‐NisI was examined by surface plasmon resonance analysis. The affinity constant K D for the interaction was calculated to be in the micromolar range. Contribution of the secreted LF‐NisI to nisin immunity was studied by replacing the lipoprotein specific nisI signal sequence with a secretion signal of non‐lipoprotein origin. Secretion of LF‐NisI in NisF/E/G‐expressing L. lactis strain NZ9840 increased significantly its nisin tolerance suggesting that the lipid‐free form of NisI could have a supportive role in nisin immunity.