Glutathione-gated K+ channels of Escherichia coli carry out K+ efflux controlled by the redox state of the cell

The kinetics of K+ efflux across the membranes of i) wild-type Escherichia coli poisoned by the thiol reagent N-ethylmaleimide, ii) K+ retention mutants and iii) glutathione-deficient mutants, have revealed a common "K+ leaky phenotype"; it is characterized by a very high rate of K+ efflux. The results suggest that the products of kefB and kefC genes could encode two K+ channels, both gated by glutathione. The possible function of these K+ channels seems to be a K+ exit controlled by the redox state of the cell; indeed, it can be inferred from the effects of several oxidants and reductants that turning on and off of the K+ efflux mediated by the channels can be correlated with the redox state of glutathione.