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Appl. Environ. Microbiol., 03 1996, 892-897, Vol 62, No. 3
T Tahara, M Oshimura, C Umezawa and K Kanatani
Lactobacillus acidophilus JCM 1132 produces a heat-stable, two- component
bacteriocin designated acidocin J1132 that has a narrow inhibitory
spectrum. Maximum production of acidocin J1132 in MRS broth was detected at
pH 5.0. Acidocin J1132 was purified by ammonium sulfate precipitation and
sequential cation exchange and reversed-phase chromatographies. Acidocin
J1132 activity was associated with two components, termed alpha and beta.
On the basis of N-terminal amino acid sequencing and the molecular masses
of the alpha and beta components, it is interpreted that the compounds
differ by an additional glycine residue in the beta component. Both alpha
and beta had inhibitory activity, and an increase in activity by the
complementary action of the two components was observed. Acidocin J1132 is
bactericidal and dissipates the membrane potential and the pH gradient in
sensitive cells, which affect such proton motive force- dependent processes
as amino acid transport. Acidocin J1132 also caused efflux of
preaccumulated amino acid taken up via a unidirectional ATP- driven
transport system. Secondary structure prediction revealed the presence of
an amphiphilic alpha-helix region that could form hydrophilic pores. These
results suggest that acidocin J1132 is a pore- forming bacteriocin that
creates cell membrane channels through the "barrel-stave" mechanism.
Copyright © 1996, American Society for Microbiology
Isolation, partial characterization, and mode of action of Acidocin J1132, a two-component bacteriocin produced by Lactobacillus acidophilus JCM 1132
Research Laboratory, Tamon Sake Brewing Co., Ltd., Nishinomiya, Japan.
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