Force production by single kinesin motors
Force production by single kinesin motors
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DOI：
10.1038/35036345
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发表时间：
2000-10-01
影响因子：
21.3
通讯作者：
Block, SM
中科院分区：
文献类型：
--
作者：
Schnitzer, MJ;Visscher, K;Block, SM
马达蛋白如驱动蛋白、肌球蛋白和聚合酶通过涉及核苷酸水解的循环将化学能转化为功。取决于负载的循环中的动力学速率识别可能发生结构变化（例如动力冲程或扩散运动）的转变。在这里，我们表明，通过建模与分子力钳获得的数据，驱动蛋白机械化学的特点是一种机制，其中负载依赖性异构化后ATP结合。该模型定量地解释了在广泛的负载和ATP水平范围内的速度数据，并表明运动可以通过两个连续的4纳米子步骤来完成。类似的考虑占驱动蛋白的持续合成能力，这被发现服从负载依赖性米氏关系。
Motor proteins such as kinesin, myosin and polymerase convert chemical energy into work through a cycle that involves nucleotide hydrolysis. Kinetic rates in the cycle that depend upon load identify transitions at which structural changes, such as power strokes or diffusive motions, are likely to occur. Here we show, by modelling data obtained with a molecular force clamp, that kinesin mechanochemistry can be characterized by a mechanism in which a load-dependent isomerization follows ATP binding. This model quantitatively accounts for velocity data over a wide range of loads and ATP levels, and indicates that movement may be accomplished through two sequential 4-nm substeps. Similar considerations account for kinesin processivity, which is found to obey a load-dependent Michaelis-Menten relationship.