Effect of the natural ATPase inhibitor on the binding of adenine nucleotides and inorganic phosphate to mitochondrial F1-ATPase

  • Klein G
  • Lunardi J
  • Vignais P
  • 5

    Readers

    Mendeley users who have this article in their library.
  • 25

    Citations

    Citations of this article.

Abstract

(1) Incubation of the beef heart mitochondrial ATPase, F1with Mg-ATP was required for the binding of the natural inhibitor, IF1, to F1to form the inactive F1-IF1complex. When F1was incubated in the presence of [14C]ATP and MgCl2, about 2 mol14C-labeled adenine nucleotides were found to bind per mol of F1; the bound14C-labeled nucleotides consisted of [14C]ADP arising from [14C]ATP hydrolysis and [14C]ATP. The14C-labeled nucleotide binding was not prevented by IF1. These data are in agreement with the idea that the formation of the F1-IF1complex requires an appropriate conformation of F1. (2) The14C-labeled adenine nucleotides bound to F1following preincubation of F1with Mg-[14C]ATP could be exchanged with added [3H]ADP or [3H]ATP. No exchange occurred between added [3H]ADP or [3H]ATP and the14C-labeled adenine nucleotides bound to the F1-IF1complex. These data suggest that the conformation of F1in the isolated F1-IF1complex is further modified in such a way that the bound14C-labeled nucleotides are no longer available for exchange. (3)32Piwas able to bind to isolated F1with a stoichiometry of about 1 mol of Piper mol of F1(Penefsky, H.S. (1977) J. Biol. Chem. 252, 2891-2899). There was no binding of32Pito the F1-IF1complex. Thus, not only the nucleotides sites, but also the Pisite, are masked from interaction with external ligands in the isolated F1-IF1complex. © 1981.

Author-supplied keywords

  • (Bovine heart mitochondria)
  • ATPase inhibitor
  • Adenine nucleotide binding
  • F1-ATPase

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Gérard Klein

  • Joel Lunardi

  • Pierre V. Vignais

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free