Survival during exposure to the electrophilic reagent N-ethylmaleimide in Escherichia coli role of KefB and KefC potassium channels

Gail Patricia Ferguson, Y Nikolaev, Debbie McLaggan, M MacLean, Ian Rylance Booth

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Abstract

The role of the KefB and KefC potassium efflux systems in protecting Escherichia coli cells against the toxic effects of the electrophile N-ethylmaleimide has been investigated. Activation of KefB and KefC aids the survival of cells exposed to high concentrations (> 100 microM) of NEM. High potassium concentrations reduce the protection afforded by activation of KefB and KefC, but the possession of these systems is still important under these conditions. The Kdp system, which confers sensitivity to the electrophile methylglyoxal, did not affect the survival of cells exposed to NEM. Survival is correlated with the reduction of the cytoplasmic pH upon activation of the channels. In particular, the kinetics of the intracellular pH (pHi) change are crucial to the retention of viability of cells exposed to NEM; slow acidification does not protect cells as effectively as rapid lowering of pHi. Cells treated with low levels of NEM (10 microM) recover faster if they activate KefB and KefC, and this correlates with changes in pHi. The pHi does not significantly alter the rate of NEM metabolism. The possible mechanisms by which protection against the electrophile is mediated are discussed.
Original languageEnglish
Pages (from-to)1007-1012
Number of pages6
JournalJournal of Bacteriology
Volume179
Issue number4
Publication statusPublished - 1 Feb 1997

Keywords

  • Antiporters
  • Bacterial Proteins
  • Biological Transport
  • Escherichia coli
  • Escherichia coli Proteins
  • Ethylmaleimide
  • Potassium
  • Potassium Channels
  • Potassium-Hydrogen Antiporters

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    Ferguson, G. P., Nikolaev, Y., McLaggan, D., MacLean, M., & Booth, I. R. (1997). Survival during exposure to the electrophilic reagent N-ethylmaleimide in Escherichia coli role of KefB and KefC potassium channels. Journal of Bacteriology, 179(4), 1007-1012.