FORCE AND VELOCITY MEASURED FOR SINGLE KINESIN MOLECULES
FORCE AND VELOCITY MEASURED FOR SINGLE KINESIN MOLECULES
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DOI：
10.1016/0092-8674(94)90060-4
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发表时间：
1994-06-03
期刊：
影响因子：
64.5
通讯作者：
BLOCK, SM
中科院分区：
文献类型：
--
作者：
SVOBODA, K;BLOCK, SM
我们测量了单个驱动蛋白分子附着在二氧化硅珠在体外运动分析移动的farce-velocity曲线。使用光学捕获干涉测量法以亚纳米精度跟踪运动，并将校准的pN大小的力施加到珠上。速度随着力的增加而线性下降，驱动蛋白分子抵抗高达5- 6pN的施加载荷而移动。在限制和饱和ATP浓度下的力-速度曲线的比较表明，驱动蛋白速度的负载依赖性减小可能是由于每分子ATP水解的净位移减少，而不仅仅是ATP周转率的减慢;因此，驱动蛋白似乎是一个松散耦合的电机。
We measured the farce-velocity curves of single kinesin molecules attached to silica beads moving in an in vitro motility assay. Optical trapping interferometry was used to track movement with subnanometer precision and to apply calibrated, pN-sized forces to the beads. Velocity decreased linearly with increasing force, and kinesin molecules moved against applied loads of up to 5-6 pN. Comparison of force-velocity curves at limiting and saturating ATP concentrations suggests that the load-dependent diminution in kinesin velocity may be due to a decrease in the net displacement per molecule of ATP hydrolyzed, not simply to a slowing of the ATP turnover rate; kinesin would therefore appear to be a loosely coupled motor.