FEBS Letters | |
Nucleotide/H+‐dependent change in Mg2+ affinity at the ATPase inhibitory site of the mitochondrial F1‐F0 ATP synthase | |
Vinogradov, A.D.1  Syroeshkin, A.V.1  Bulygin, V.V.1  | |
[1] Department of Biochemistry, School of Biology, Moscow State University, 119899 Moscow, Russian Federation | |
关键词: F1-F0 ATPase; Nucleotide-binding sites; Mg2+ binding; ClCCP; carbonylcyanide m-chlorophenylhydrazone; HEPES; N-2-hydroxyethylpiperazine-N'-ethanesulfonic acid; | |
DOI : 10.1016/0014-5793(93)80991-3 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
The interactions between ADP and Mg2+ that result in the slowly reversible inhibition of the mitochondrial F1-F0 ATPase were studied. The K i 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 (K i = 2.10−6 M) in the presence of stoichiometric ADP and the affinity for inhibitory Mg2+ decreases to a K i, value of 7.10−5 M when the second nueleotide binding site with k d = 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.
【 授权许可】
Unknown
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