Oxidative phosphorylation in right-side-out membrane vesicles from Escherichia coli.
Oxidative phosphorylation in Escherichia coli membrane vesicles with a right-side-out orientation and loaded with ADP was investigated. Substrates of the electron transport chain could energize the phosphorylation of ADP, with the order of effectiveness being D-lactate greater than reduced phenazinemethosulfate greater than succinate greater than reduced nicotinamide adenine dinucleotide. Inhibitors of D-lactate oxidation, proton conductors, and inhibitor of the Mg2+ATPase (EC 3.6.1.3) all inhibited oxidative phosphorylation when coupled to D-lactate oxidation. ATP synthesis was absent in membrane vesicles prepared from a mutant strain lacking the Mg2+ATPase. Valinomycin or nigericin partially inhibited oxidative phosphorylation in the presence of potassium. Valinomycin plus nigericin completely inhibited ATP synthesis. The effect of various agents on the respiration-dependent establishment of a transmembrane pH gradient was also examined. NaCN and carbonyl cyanide p-trifluoromethoxyphenylhydrazone inhibited the establishment of a pH gradient while dicyclohexylcarbodiimide had no effect. These results are in good agreement with a chemiosmotic model for oxidative phosphorylation.
D001149:Arsenates / Q000494:pharmacology; D001386:Azides / Q000494:pharmacology; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism*; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004140:Dinitrophenols / Q000494:pharmacology; D004579:Electron Transport; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010085:Oxidative Phosphorylation / Q000187:drug effects
D001149:Arsenates; D001386:Azides; D004140:Dinitrophenols; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D000431:Ethanol; D004024:Dicyclohexylcarbodiimide