Potassium channel activation by glutathione-S-conjugates in Escherichia coli: protection against methylglyoxal is mediated by cytoplasmic acidification

Gail Patricia Ferguson, Debbie McLaggan, Ian Rylance Booth

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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 pHi and the time at which acidification takes place. Alterations in the pHi do not accelerate the rate of detoxification of methylglyoxal. The mechanism by which methylglyoxal causes cell death and the implications for pHi-mediated resistance to methylglyoxal are discussed.
Original languageEnglish
Pages (from-to)1025-1033
Number of pages9
JournalMolecular Microbiology
Issue number6
Publication statusPublished - 1 Sep 1995



  • Acetic Acid
  • Acetic Acids
  • Antiporters
  • Bacterial Proteins
  • Chemistry, Physical
  • Cytoplasm
  • Escherichia coli
  • Escherichia coli Proteins
  • Glutathione
  • Hydrogen-Ion Concentration
  • Intracellular Fluid
  • Oxidative Stress
  • Physicochemical Phenomena
  • Potassium
  • Potassium Channels
  • Potassium-Hydrogen Antiporters
  • Protons
  • Pyruvaldehyde

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