Tight Chemomechanical Coupling of the F1 Motor Relies on Structural Stability
Tight Chemomechanical Coupling of the F1 Motor Relies on Structural Stability
复制标题
F1 电机的紧密化学机械耦合依赖于结构稳定性
DOI：
10.1016/j.bpj.2020.04.039
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发表时间：
2020
影响因子：
3.4
通讯作者：
Muneyuki Eiro
中科院分区：
文献类型：
--
作者：
Tanaka Mana;Kawakami Tomohiro;Okaniwa Tomoaki;Nakayama Yohei;Toyabe Shoichi;Ueno Hiroshi;Muneyuki Eiro
F1马达是一种旋转分子马达，可确保ATP水解/合成反应和旋转步骤之间的紧密化学机械耦合。然而，这种紧密耦合的机制仍有待阐明。在这项研究中，我们在使用F1β E190 D突变体的单分子实验中使用电旋转来证明失速扭矩显著小于野生型F1，表明该突变体的松散耦合，尽管显示出与野生型相似的步进扭矩。对α3β3-亚复合物进行热处理和凝胶过滤后的ATP酶活性实验表明，β E190 D突变体的结构不稳定。我们的研究结果表明，紧密的化学机械耦合的F1马达依赖于F1的结构稳定性。我们还讨论了步进转矩和失速转矩之间的差异。
The F1motor is a rotating molecular motor that ensures a tight chemomechanical coupling between ATP hydrolysis/synthesis reactions and rotation steps. However, the mechanism underlying this tight coupling remains to be elucidated. In this study, we used electrorotation in single-molecule experiments using an F1βE190D mutant to demonstrate that the stall torque was significantly smaller than the wild-type F1, indicating a loose coupling of this mutant, despite showing similar stepping torque as the wild-type. Experiments on the ATPase activity after heat treatment and gel filtration of theα3β3-subcomplex revealed the unstable structure of theβE190D mutant. Our results suggest that the tight chemomechanical coupling of the F1motor relies on the structural stability of F1. We also discuss the difference between the stepping torque and the stall torque.