A single mutation at the catalytic site of TF1‐α3β3γ complex switches the kinetics of ATP hydrolysis from negative to positive cooperativity

FEBS Letters

Muneyuki, Eiro²  Odaka, Masafumi¹  Yoshida, Masasuke² 

[1] Biochemical Systems Laboratory, The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako, Saitama 351-01, Japan;Research Laboratory of Resources Utilization, Tokyo Institute of Technology, Nagatsuta 4259, Midori-ku, Yokohama 226, Japan

关键词: F1-ATPase;    Cooperative kinetics;    Binding change model;    F1;    a water-soluble part of H+-ATP synthase;    TF1;    F1 from thermophilic Bacillus PS3;    MF1;    F1 from beef heart mitochondria;   

DOI  :  10.1016/S0014-5793(97)00878-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Previously, we reported the substitution of Tyr³⁴¹ of the F₁-ATPase β subunit from a thermophilic Bacillus strain PS3 with leucine, cysteine, or alanine (M. Odaka et al. J. Biochem., 115 (1994) 789–796). These mutations resulted in a great decrease in the affinity of the isolated β subunit for ATP-Mg and an increase in the apparent K _m of the α₃β₃γ complex in ATP hydrolysis when examined above 0.1 mM ATP. Here, we examined the ATPase activity of the mutant complexes in a wide range of ATP concentration and found that the mutants exhibited apparent positive cooperativity in ATP hydrolysis. This is the first clear demonstration that a single mutation in the catalytic sites converts the kinetics from apparent negative cooperativity in the wild-type α₃β₃γ complex to apparent positive cooperativity. The conversion of apparent cooperativity could be explained in terms of a simple kinetic scheme based on the binding change model proposed by Boyer.

【 授权许可】

Unknown