F1-ATPase rotates by an asymmetric, sequential mechanism using all three catalytic subunits
F1-ATPase rotates by an asymmetric, sequential mechanism using all three catalytic subunits
复制标题
DOI：
10.1038/nsmb1296
复制
发表时间：
2007-09-01
影响因子：
16.8
通讯作者：
Yoshida, Masasuke
中科院分区：
文献类型：
--
作者：
Ariga, Takayuki;Muneyuki, Eiro;Yoshida, Masasuke
F-1-ATP酶是FoF 1- ATP合酶的催化部分，它使α（3）β（3）圆柱体内的中心c亚基以120度的步长旋转，每一步消耗一个ATP分子。然而，每个β亚基的催化活性如何与其他两个β亚基协调以驱动旋转仍然未知。在这里，我们表明，混合F-1含有一个或两个突变的β亚基与改变催化动力学旋转在一个不对称的逐步方式。对旋转的分析表明，对于任何给定的β亚基，该亚基在0度结合ATP，在类似于200度切割ATP，并在类似于320度进行第三次催化事件。这证明了F-1复合物活性的协同性质，其中所有三个β亚基参与驱动c亚基的每个120度旋转，具有120度相位差，我们将该过程描述为“顺序三位点机制”。
F-1- ATPase, the catalytic part of FoF1- ATP synthase, rotates the central c subunit within the alpha(3)beta(3) cylinder in 120 degrees steps, each step consuming a single ATP molecule. However, how the catalytic activity of each beta subunit is coordinated with the other two beta subunits to drive rotation remains unknown. Here we show that hybrid F-1 containing one or two mutant beta subunits with altered catalytic kinetics rotates in an asymmetric stepwise fashion. Analysis of the rotations reveals that for any given beta subunit, the subunit binds ATP at 0 degrees, cleaves ATP at similar to 200 degrees and carries out a third catalytic event at similar to 320 degrees. This demonstrates the concerted nature of the F-1 complex activity, where all three beta subunits participate to drive each 120 degrees rotation of the c subunit with a 120 degrees phase difference, a process we describe as a 'sequential three- site mechanism'.