GLUTATHIONE AND THE GATED POTASSIUM CHANNELS OF ESCHERICHIA-COLI

Glutathione-deficient mutants of E. coli required high K+ concentrations for growth, unless supplemented with glutathione. The unsupplemented mutants exhibited a rapid lead of K+ when transferred to a K+-free medium and a fast K+ turnover at the steady state of K+ accumulation, contrasting with the slow rate of the same processes in the wild-type. The steady-state level of K+ accumulation in low K+ medium increased immediately on addition of glutathione, even in the absence of protein synthesis. K+-independent revertants possessed restored glutathione synthesis. Many properties of glutathione-deficient mutants were identical to those of the K+ leaky K-B- and K-B- mutants, which however, have a normal glutathione content. Both types of mutants differ from the wild-type in their response to thiol reagents in that no rapid loss of K+ is observed: they have, however, clear-cut differences under these circumstances. The products of trkB and trkC genes are evidently essential for the formation of the K+ channel. Glutathione evidently plays an important role in the gating process.