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pubmed:abstractText |
It is shown that the uptake of K+ ions by anaerobically grown E. coli bacteria, which perform glycolysis with the production of H2 in exchange for H+ ions, which are extruded from the cells, occurs with a fixed stoichiometry of N,N'-dicyclohexylcarbodiimide-sensitive ion fluxes (2H+/K+). This process is observed in the precursor strain and arcB mutant, and is destroyed in arcA mutant. The K(+)-uptake by the latter mutant, which proceeds with a moderate affinity (KM 2.0 mM) and is triggered by a positive shock, is sensitive to external osmotonicity. The K(+)-uptake by the arcA mutant is also inhibited by N,N'-dicyclohexylcarbodiimide and has a variable stoichiometry of N,N'-dicyclohexylcarbodiimide-sensitive ion fluxes and does not significantly change in the presence of valinomycin and with varying temperature, whereas the intracellular activity of K+ ions is lower. The Arc-system for the control of synthesis of respiratory enzymes in E. coli participates in the regulation of the K(+)-transporting TrkA system, which directly interacts with F0F1 H-ATPasa; this system in the arcA mutant operates independent of F0F1 and interacts with the latter by mediation of the proton gradient.
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