Binding of TNP‐ATP and TNP‐ADP to the non‐catalytic sites of Escherichia coli F1‐ATPase

FEBS Letters

Senior, Alan E¹  Weber, Joachim¹ 

[1] University of Rochester Medical Center, Department of Biochemistry and Biophysics, Box 712, Rochester, NY 14642, USA

关键词: Oxidative phosphorylation;    F1-ATPase;    Nucleotide binding site;    TNP-ATP or TNP-ADP;    2′;    3′-O-(2;    4;    6-trinitrophenyl)adenosine 5′-triphosphate or -diphosphate;    respectively;   

DOI  :  10.1016/S0014-5793(97)00773-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Using site-directed-tryptophan fluorescence, parameters for equilibrium binding of (Mg)TNP-ATP and (Mg)TNP-ADP to non-catalytic sites of Escherichia coli F₁-ATPase were determined. All three non-catalytic sites showed the same affinity for MgTNP-ATP (K _d=0.2 μM) or MgTNP-ADP (K _d=6.5 μM) whereas even at concentrations of 100 μM no binding of uncomplexed TNP-ATP or TNP-ADP was observed. The results demonstrate that the three non-catalytic sites bind TNP-nucleotides non-cooperatively, and emphasize the importance of Mg²⁺ for non-catalytic-site nucleotide binding. Parameters for binding of (Mg)TNP-ADP to the three catalytic sites were also determined, and showed marked cooperativity. This work completes the set of thermodynamic parameters for equilibrium binding of (Mg)TNP-ATP and (Mg)TNP-ADP to all six nucleotide sites of F₁, providing essential information to fully exploit the potential of these nucleotide analogs in studies of F₁-ATPase.

【 授权许可】

Unknown