1] Department of Applied Chemistry, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan [2] PRESTO, JST, Bunkyo-ku, Tokyo 113-8656, Japan.
Department of Applied Chemistry, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
Nat Commun. 2014 Apr 1;5:3486. doi: 10.1038/ncomms4486.
F1-ATPase is a rotary motor protein driven by ATP hydrolysis. The rotary motion of F1-ATPase is tightly coupled to catalysis, in which the catalytic sites strictly obey the reaction sequences at the resolution of elementary reaction steps. This fine coordination of the reaction scheme is thought to be important to achieve extremely high chemomechanical coupling efficiency and reversibility, which is the prominent feature of F1-ATPase among molecular motor proteins. In this study, we intentionally change the reaction scheme by using single-molecule manipulation, and we examine the resulting effect on the rotary motion of F1-ATPase. When the sequence of the products released, that is, ADP and inorganic phosphate, is switched, we find that F1 frequently stops rotating for a long time, which corresponds to inactivation of catalysis. This inactive state presents MgADP inhibition, and thus, we find that an improper reaction sequence of F1-ATPase catalysis induces MgADP inhibition.
F1-ATP 酶是一种由 ATP 水解驱动的旋转分子马达。F1-ATP 酶的旋转运动与催化紧密偶联,其中催化位点严格遵循基本反应步骤的反应序列。这种精细的反应方案协调被认为对于实现极高的化学机械耦合效率和可逆性很重要,这是 F1-ATP 酶在分子马达蛋白中的突出特点。在这项研究中,我们通过使用单分子操纵有意改变反应方案,并检查其对 F1-ATP 酶旋转运动的影响。当释放的产物(即 ADP 和无机磷酸盐)的顺序发生变化时,我们发现 F1 经常长时间停止旋转,这对应于催化失活。这种失活状态表现出 MgADP 抑制,因此,我们发现 F1-ATP 酶催化的不当反应序列会诱导 MgADP 抑制。