An electrochemical study of energy-dependent potassium accumulation in E. coli: VII. On the structure of H+−K+-exchanging systems

Summary Comparative analysis of the H + −K + exchanges in E. coli , strains AN 120 and AN 382, was carried out. Strain AN 120 with the inoperative complex F 1 · F 0 does not possess the working TrkA system, the TrkF system retaining the essential rate of the H + −K + exchange. The strain AN 382 (F 0 is insensitive to DCCD [13]) manifested the absence of the usual DCCD sensitivity of both TrkA and TrkF . Moreover, the TrkA system in this mutant has become insensitive to the variation of osmotic pressure in medium, confirming the hypothesis of F 1 · F 0 rather than TrkA being actuated by external osmotic pressure through the outside of the H + channel F 0 . We do not exclude the fact that TrkA and F 1 · F 0 form the supercomplex for the joint employment of ATP and TrkA with F 0 is the second supercomplex for the joint utilization of both Δµ H+ and Δµ K+