Coupling factor ATPase complex of Rhodospirillum rubrum. Purification and characterization of an oligomycin and N,N'-dicyclohexylcarbodiimide-sensitive (Ca+ + Mg2+)-ATPase.
An ATPase complex sensitive to the energy transfer inhibitors oligomycin, dicyclohexylcarbodiimide and venturicidin has been solubilized from Rhodospirillum rubrum chromatophores with Triton X-100 and further purified by centrifugation on a glycerol gradient. The partially purified RrFo . F1 contains 13 distinct polypeptide subunits, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, including the subunits of the oligomycin-sensitive, water-soluble RrF1 ATPase. The ATPase activity of RrF0 . F1 as that of the membrane-bound enzyme complex depends on Ca2+ or Mg2+ and from detailed kinetic studies it is concluded that the divalent cation-ATP complex is the substrate for both ATPase complexes. Free ATP and free Mg2+ act as competitive inhibitors, with Ki values of 1 mM and 7 muM, respectively. The subunit composition of the purified RrFo . F1 and its similarity to the membrane-bound ATPase with respect to cation dependence and sensitivity to energy transfer inhibitors suggests that it contains all the subunits of the R. rubrum coupling factor-ATPase complex.
D001313:Aurovertins / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000302:isolation & purification / Q000378:metabolism*; D002234:Carbodiimides / Q000494:pharmacology*; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008970:Molecular Weight; D009840:Oligomycins / Q000494:pharmacology*; D010086:Oxidative Phosphorylation Coupling Factors / Q000378:metabolism*; D012247:Rhodospirillum rubrum / Q000201:enzymology*; D014698:Venturicidins / Q000494:pharmacology
D001313:Aurovertins; D002234:Carbodiimides; D009840:Oligomycins; D010086:Oxidative Phosphorylation Coupling Factors; D014698:Venturicidins; D004024:Dicyclohexylcarbodiimide; D000252:Calcium-Transporting ATPases; D008274:Magnesium