Induction of the Escherichia coli cytochrome d by low delta mu H+ and by sodium ions.
Regulation of synthesis of cytochrome d in Escherichia coli has been studied using mutants with cytochrome-d--beta-galactosidase gene fusions. It was shown that various protonophorous uncouplers, when added to the growth medium, cause induction of the cytochrome d synthesis. The cytochrome-d-inducing activity of uncouplers correlates with their ability to inhibit such a delta mu (H+)-driven function as motility of the E. coli cells. An increase in the Na+ concentration in the growth medium from 1.5 mM to 25 mM results in induction of the cytochrome d synthesis. The cytochrome-d-inducing effect of uncouplers is much more pronounced when the Na+ concentration is high than when it is low. These data are in agreement with the assumption that cytochrome d is involved in the Na+ energetics substituting for the H+ energetics when the latter appears to be inefficient. Mutations in arcA or arcB genes (but not in fnr gene) completely prevent the increase in the cytochrome d level induced by uncouplers but are without effect on that induced by Na+. It is assumed that in the control of the cytochrome d synthesis, the Arc system is involved in the delta mu H+ sensing whereas sensing of delta mu Na+ (or of the Na+ concentration) is mediated by some other receptor system.
Bogachev
A V
AV
Department of Bioenergetics, A. N. Belozersky Institute of Phisico-Chemical Biology, Moscow State University, Russia.
Murtazine
R A
RA
Shestopalov
A I
AI
Skulachev
V P
VP
D017937:Cytochrome d Group / Q000096:biosynthesis* / Q000235:genetics; D004790:Enzyme Induction; D004926:Escherichia coli / Q000201:enzymology*; D006859:Hydrogen / Q000494:pharmacology; D007477:Ions; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D012964:Sodium / Q000494:pharmacology; D001616:beta-Galactosidase / Q000096:biosynthesis* / Q000235:genetics
D007477:Ions; D011993:Recombinant Fusion Proteins; D006859:Hydrogen; D017937:Cytochrome d Group; D012964:Sodium; D001616:beta-Galactosidase