title: The maintenance of the energized membrane state and its relation to active transport in Escherichia coli.
abstract: 1. An ATPase mutant of Escherichia coli and two partial revertants of that mutant were examined for the ability to generate a high energy membrane state with D-lactate or ATP, as measured by the quenching of the fluorescent dye quinacrine. 2. All three strains showed reductions in the aerobically-driven quenching of fluorescence compared to the wild type, but the reduction could be reversed by the addition of eitherN,N'-dicyclohexylcarbodiimide or the crude soluble ATPase of the wild type. 3. The mutant exhibited a decreased ability to accumulate sugars and amino acids and showed an increased permeability to protons. 4. One partial revertant showed a slight increase in active transport and a slight decrease in proton permeability. 5. The other partial revertant showed a large increase in transport ability and a large decrease in proton permeability. 6. A model is proposed in which the conformation of the Mg-2+-ATPase is important in the utilization of energy derived from the electron transport chain and this function is independent of the catalytic activity of the Mg-2+-ATPase.
mesh_terms: D000251:Adenosine Triphosphatases; D000255:Adenosine Triphosphate / Q000378:metabolism; D001693:Biological Transport, Active; D002462:Cell Membrane / Q000378:metabolism*; D004735:Energy Transfer; D004926:Escherichia coli / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D013045:Species Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D007773:Lactates; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases