Nucleotide/H(+)-dependent change in Mg2+ affinity at the ATPase inhibitory site of the mitochondrial F1-F0 ATP synthase
| Autor: | V.V. Bulygin, Andrei D. Vinogradov, A.V. Syroeshkin |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
inorganic chemicals
Stereochemistry ATPase Biophysics F1-F0 ATPase Biology Mitochondrion Inhibitory postsynaptic potential Biochemistry Mitochondria Heart Structural Biology Genetics Animals Nucleotide Magnesium Binding site Enzyme Inhibitors Molecular Biology Nucleotide-binding sites chemistry.chemical_classification Adenosine Triphosphatases Ions Binding Sites ATP synthase Active site Cell Biology Hydrogen-Ion Concentration Mg2+ binding Adenosine Diphosphate Proton-Translocating ATPases Enzyme chemistry biology.protein Cattle Hydrogen |
| Zdroj: | FEBS letters. 328(1-2) |
| ISSN: | 0014-5793 |
| Popis: | The interactions between ADP and Mg2+ that result in the slowly reversible inhibition of the mitochondrial F1-F0 ATPase were studied. The Ki for the inhibitory Mg2+ is shown to be strongly dependent on the occupation of the nucleotide-binding sites. The inhibitory binding site for Mg2+ is not seen unless a stoichiometric amount of ADP is added [Biochem. J. 276 (1991) 149-156]; it appears (Ki = 2.10−6 M) in the presence of stoichiometric ADP and the affinity for inhibitory Mg2+ decreases to a Ki, value of 7.10−5 M when the second nueleotide binding site with kd = 5.10−6 M is loaded with ADP. The binding of the inhibitory Mg2+ is competitively inhibited by H+ ions within the pH interval 6.8–8.2. The nucleotide-dependent affinity transition of the Mg2+-specific site suggests that H+/Mg2+ exchange may play an important role in the catalytic mechanism of ATP synthesis/hydrolysis at the active site(s) of F1-F0 ATP synthase. |
| Databáze: | OpenAIRE |
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