A mutant ATP synthetase of Escherichia coli with an altered sensitivity to N,N' -dicyclohexylcarbodiimide: characterization in native membranes and reconstituted proteoliposomes.
Dicyclohexylcarbodiimide-resistant mutants of Escherichia coli were isolated and characterized In one mutant the unc genes and affects the membrane-integrated part of the ATP synthetase. The sensitivity of ATP synthetase functions to N,N' -dicyclohexylcarbodiimide was compared in wild-type and mutant membranes. The membrane-integrated part of the wild-type ATP synthetase is highly sensitive to ATP-dependent membrane energization and restoration of lactate-dependent energization of ATPase-depleted membranes. In mutant membranes this concentration has only a slight effect on these activities whereas a severe inhibition is obtained at 200 muM. Using  the highly water-soluble 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide theactivities of wild-type and mutant membranes are inhibited to the same extent. TheATP synthetase of wild-type and mutant was partially purified and incorporated muM. Uinto liposomes. These showed an uncoupler-sensitive ATP-32Pi exchange and ATP-dependent quenching of acridine-dye fluorescence. The activities of mutant and wild-type proteoliposomes exhibit the same pattern of sensitivity to dicyclohexylcarbodiimide as the corresponding membranes.
D000244:Adenosine Diphosphate; D000251:Adenosine Triphosphatases / Q000378:metabolism; D002234:Carbodiimides / Q000494:pharmacology*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008081:Liposomes / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism; D009154:Mutation; D010770:Phosphotransferases / Q000378:metabolism; D011510:Proteolipids / Q000378:metabolism; D013050:Spectrometry, Fluorescence
D002234:Carbodiimides; D008081:Liposomes; D009097:Multienzyme Complexes; D011510:Proteolipids; D004024:Dicyclohexylcarbodiimide; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000244:Adenosine Diphosphate; D010770:Phosphotransferases; D000251:Adenosine Triphosphatases