Inhibitory and anchoring domains in the ATPase inhibitor protein IF1 of bovine heart mitochondrial ATP synthase.
The inhibitor protein IF1 is a basic protein of 84 residues which inhibits the ATPase activity of the mitochondrial FoF1-ATP synthase complex without having any effect on ATP synthesis. Results of cross-linking and limited proteolysis experiments are presented showing that in the intact FoF1 complex "in situ," in the inner membrane of bovine heart mitochondria, the central segment of IF1 (residues 42-58) binds to the alpha and beta subunits of F1 in a pH dependent process, and inhibits the ATPase activity. The C-terminal region of IF1 binds, simultaneously, to the OSCP subunit of Fo in a pH-independent process. This binding keeps IF1 anchored to the complex, both under inhibitory conditions, at acidic pH, and noninhibitory conditions at alkaline pH.
Zanotti
Franco
F
Department of Medical Biochemistry and Biology, University of Bari, Italy.
Raho
Gabriella
G
Gaballo
Antonio
A
Papa
Sergio
S
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D002478:Cells, Cultured; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008929:Mitochondria, Heart / Q000737:chemistry / Q000378:metabolism*; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D000097795:ATPase Inhibitory Protein
D004791:Enzyme Inhibitors; D025261:Mitochondrial Proton-Translocating ATPases; D011506:Proteins; D000097795:ATPase Inhibitory Protein