title: Effect of disulfide cross-linking between alpha and delta subunits on the properties of the F1 adenosine triphosphatase of Escherichia coli.
abstract: Under very mild oxidizing conditions the delta subunit of the F1-ATPase of Escherichia coli can be crosslinked by a disulfide linkage to one of the alpha subunits of the enzyme. The cross-linked ATPase resembles the native enzyme in the following properties: specific activity; activation by lauryldimethylamine N-oxide (LDAO); binding of aurovertin D and ADP; cross-linking products with 3,3'-dithiobis(succinimidyl propionate); binding to ATPase-stripped everted membrane vesicles and the N,N'-dicyclohexylcarbodiimide sensitivity of the rebound enzyme. However, the rebound crosslinked ATPase differed from the native enzyme in lacking the ability to restore NADH oxidation - and ATP hydrolysis-dependent quenching of the fluorescence of quinacrine to ATPase-stripped membrane vesicles. It is proposed that the delta subunit is involved in the proton pathway of the ATPase, and that this pathway is affected in the alpha delta-cross-linked enzyme. The mechanism for activation of the ATPase by LDAO was examined. Evidence against the proposal of Lötscher, H.-R., De Jong, C. and Capaldi, R.A. (Biochemistry (1984) 23, 4140-4143) that activation involves displacement of the epsilon subunit from an active site on a beta subunit was obtained.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001313:Aurovertins; D002499:Centrifugation, Density Gradient; D002850:Chromatography, Gel; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004123:Dimethylamines / Q000494:pharmacology; D004220:Disulfides; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology; D005453:Fluorescence; D009243:NAD / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000032:analysis*
chemical_list: D001313:Aurovertins; D004123:Dimethylamines; D004220:Disulfides; D009243:NAD; C014518:dodecyldimethylamine oxide; D004024:Dicyclohexylcarbodiimide; C039026:aurovertin D; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases