THE FORCE GENERATED BY A SINGLE KINESIN MOLECULE AGAINST AN ELASTIC LOAD
THE FORCE GENERATED BY A SINGLE KINESIN MOLECULE AGAINST AN ELASTIC LOAD
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DOI：
10.1073/pnas.92.2.574
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发表时间：
1995-01-17
影响因子：
11.1
通讯作者：
HOWARD, J
中科院分区：
文献类型：
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作者：
MEYHOFER, E;HOWARD, J
为了探索马达蛋白驱动蛋白沿沿着微管运动的机制，我们开发了一种高灵敏度的技术来测量单个马达分子所施加的力。在这项技术中，微管的一端连接到校准刚度的柔性玻璃纤维的尖端。微管的另一端与稀疏地涂覆有驱动蛋白的表面接触。通过在光电二极管检测器上对玻璃纤维的尖端进行成像，可以检测到驱动蛋白对微管的位移小至1 nm，并且可以分辨小至1 pN的力。利用这种力纤维装置，我们表征了这种分子马达的机械输出。驱动蛋白分子沿微管表面沿着运动的速度随着弹力的增加而线性下降。阻止单个驱动蛋白分子所需的力为5.4 +/- 1.0 pN（平均值+/- SD; n = 16），与纤维的刚度、流体的阻尼以及ATP浓度是高还是低无关。
To probe the mechanism by which the motor protein kinesin moves along microtubules, we have developed a highly sensitive technique for measuring the force exerted by a single motor molecule. In this technique, one end of a microtubule is attached to the tip of a flexible glass fiber of calibrated stiffness. The other end of the microtubule makes contact with a surface sparsely coated with kinesin, By imaging the tip of the glass fiber on a photodiode detector, displacement of the microtubule by kinesin through as little as 1 nm can be detected and forces as small as 1 pN resolved. Using this force-fiber apparatus we have characterized the mechanical output of this molecular motor, The speed at which a molecule of kinesin moved along the surface of a microtubule decreased linearly as the elastic force was increased. The force required to stop a single kinesin molecule was 5.4 +/- 1.0 pN (mean +/- SD; n = 16), independent of the stiffness of the fiber, the damping from the fluid, and whether the ATP concentration was high or low.