title: Interaction of Escherichia coli adenosine triphosphatase with aurovertin and citreoviridin: inhibition and fluorescence studies.
abstract: Aurovertins B and D inhibited the adenosine triphosphatase (ATPase) activity of soluble Escherichia coli coupling factor ATPase (BF1) isolated from wile-type E. coli K-12. Half inhibition was obtained with 2 microns aurovertin B and 0.9 microns aurovertin D. Aurovertins B and D had no inhibitory effect on BF1 isolated from the aurovertin-resistant E. coli mutant MA12. Acetylation or saponification of aurovertin D yielded a derivative which was devoid of inhibitory effect on BF1. Citreoviridin also inhibited wild-type BF1 but with much less efficiency (half inhibition at 60 microns) than aurovertin. Citreoviridin had no effect on the aurovertin-resistant BF1. The fluorescence intensity of aurovertins B and D was markedly enhanced upon addition to purified BF1. There was no enhancement of fluorescence when the aurovertins were added to BF1 isolated from the aurovertin-resistant mutant. The fluorescence of the aurovertin-BF1 complex was enhanced by adenosine 5'-diphosphate and by low concentrations of adenosine 5'-triphosphate. The adenosine 5'-diphosphate-enhanced fluorescence of the aurovertin-BF1 complex was quenched by high concentrations of adenosine 5'-triphosphate or by MG2+. Aurovertin bound selectively to the beta subunit of BF1 isolated from wile-type cells. By complementation assays in vitro, using a reconstituted system made of subunits isolated from wild-type and aurovertin-resistant BF1, it was shown that the altered peptide in aurovertin-resistant BF1 was the beta subunit.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D001313:Aurovertins / Q000378:metabolism / Q000494:pharmacology*; D002413:Cations, Divalent / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D011714:Pyrans / Q000494:pharmacology*
chemical_list: D001313:Aurovertins; D002413:Cations, Divalent; D011714:Pyrans; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C014416:citreoviridin