Tikhonov A N, Pogrebnaia A F, Romanovskiĭ Iu M
Physical Department, Lomonosov Moscow State University, Vorob'evy Gory, Moscow, 119899 Russia.
Biofizika. 2003 Nov-Dec;48(6):1052-70.
The first part of this paper is a brief review of works concerned with the mechanisms of functioning of F0F1-ATP synthases. F0F1-ATP syntheses operate as rotating molecular machines that provide the synthesis of ATP from ADP and inorganic phosphate (Pi) in mitochondria, chloroplasts, and bacteria at the expense of the energy of electrochemical gradient of hydrogen ions generated across energy-transducing mitochondrial, chloroplast or, bacterial membranes. A distinguishing feature of these enzymes is that they operate as rotary molecular motors. In the second part of the work, we calculated the contribution of electrostatic interactions between charged groups of a substrate (MgATP), reaction products (MgADP and Pi), and charged amino acid residues of the F1-ATPase molecule to energy changes associated with the binding of ATP and its chemical transformations in the catalytic centers located at the interface of the alpha- and beta-subunits of the enzyme (oligomer complex alpha 3 beta 3 gamma of bovine mitochondrial ATPase). The catalytic cycle of ATP hydrolysis considered in the work includes conformational changes of alpha- and beta-subunits caused by unidirectional rotations of the central gamma-subunit. The results of our calculations are consistent with the idea that the energetically favorable process of ATP binding to the "open" catalytic center of F1-ATPase initiates the rotation of the gamma-subunit followed by ATP hydrolysis in another ("closed") catalytic center of the enzyme.
本文的第一部分简要回顾了与F0F1 - ATP合酶功能机制相关的研究工作。F0F1 - ATP合酶作为旋转分子机器发挥作用,它利用跨线粒体、叶绿体或细菌能量转换膜产生的氢离子电化学梯度能量,在线粒体、叶绿体和细菌中由二磷酸腺苷(ADP)和无机磷酸(Pi)合成三磷酸腺苷(ATP)。这些酶的一个显著特点是它们作为旋转分子马达运行。在工作的第二部分,我们计算了底物(MgATP)、反应产物(MgADP和Pi)的带电基团与F1 - ATP酶分子的带电氨基酸残基之间的静电相互作用对与ATP结合及其在位于酶的α和β亚基界面的催化中心(牛线粒体ATP酶的寡聚体复合物α3β3γ)中的化学转化相关的能量变化的贡献。工作中考虑的ATP水解催化循环包括由中心γ亚基单向旋转引起的α和β亚基的构象变化。我们的计算结果与以下观点一致:ATP与F1 - ATP酶的“开放”催化中心结合的能量有利过程启动了γ亚基的旋转,随后在酶的另一个(“封闭”)催化中心发生ATP水解。