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Potassium channel activation by glutathione‐S‐conjugates in Escherichia coli : protection against methylglyoxal is mediated by cytoplasmic acidification
Author(s) -
Ferguson Gail P.,
McLaggan Debra,
Booth Ian R.
Publication year - 1995
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1995.mmi_17061025.x
Subject(s) - methylglyoxal , biology , escherichia coli , cytoplasm , glutathione , biochemistry , potassium channel , potassium , conjugate , microbiology and biotechnology , biophysics , chemistry , enzyme , organic chemistry , gene , mathematical analysis , mathematics
Escherichia coli possesses two glutathione‐gated potassium channels, KefB and KefC, that are activated by glutathione‐S‐conjugates formed with methylglyoxal. We demonstrate that activation of the channels leads to cytoplasmic acidification and that this protects cells during electrophilic attack. Further, we demonstrate that mutants lacking the channels can be protected against the lethal effects of methylglyoxal by acidification of the cytoplasm with a weak acid. The degree of protection is determined by the absolute value of the pH i and the time at which acidification takes place. Alterations in the pH i do not accelerate the rate of detoxification of methylglyoxal. The mechanism by which methylglyoxal causes cell death and the implications for pH i ‐mediated resistance to methylglyoxal are discussed.