Characterization of the nucleotide tight‐binding sites of the isolated mitochondrial F1‐ATPase

FEBS Letters

Milgrom, Ya.M.¹  Murataliev, M.B.¹ 

[1] A.N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, Moscow State University, 119899 Moscow, USSR

关键词: F1-ATPase;    Tightly bound nucleotide;    Nucleotide-binding site;    Mops;    morpholinepropanesulfonic acid;   

DOI  :  10.1016/0014-5793(87)81209-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The properties of the nucleotides tightly bound with mitochondrial F₁-ATPase were examined. One of three bound nucleotide molecules is localized at the site with K _dR̃10⁻⁷ M and released with k _off∼0.1 s⁻¹. The second nucleotide molecule is bound with the enzyme with K _d ∼10⁻⁸ M and k _off for its dissociation is 3 × 10⁻⁴ s⁻¹. The third is never released even in the presence of 1 mM ATP or ADP. The last two nucleotides are believed to be bound at the noncatalytic sites of F₁-ATPase. Pyrophosphate promotes liberation of two releasable nucleotide molecules, decreasing the affinity of the enzyme to AD(T)P. From the results obtained it follows that the only suitable criterion for localization of the nucleotide at the F₁-ATPase catalytic site is the high rate (k _off ≧ 0.1 s⁻¹) of its spontaneous release.

【 授权许可】

Unknown