Kinesin rotates unidirectionally and generates torque while walking on microtubules
Kinesin rotates unidirectionally and generates torque while walking on microtubules
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DOI：
10.1073/pnas.1706985114
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发表时间：
2017-10-10
影响因子：
11.1
通讯作者：
Schaffer, Erik
中科院分区：
文献类型：
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作者：
Ramaiya, Avin;Roy, Basudev;Schaffer, Erik
细胞骨架马达驱动许多重要的细胞过程。例如，驱动蛋白-1以逐步的方式沿沿着微管运输货物。为了解决步进过程中的旋转，我们使用了光镊结合光学量角器和扭转平衡，使用高双折射微球直接和同时测量的移位，旋转，力，和扭矩产生的个别驱动蛋白-1电机。虽然，在低浓度的5 '-三磷酸腺苷（ATP），电机不产生扭矩，我们发现，电机易位沿着微管在饱和ATP浓度单向旋转，产生显着的扭矩上的探针。考虑到旋转功使驱动器成为一个高效的机器。这些结果意味着电机的步态如下旋转的手在手的机制。我们的方法通常适用于研究分子机器的旋转和线性运动，我们的研究结果对驱动蛋白驱动的细胞过程有影响。
Cytoskeletal motors drive many essential cellular processes. For example, kinesin-1 transports cargo in a step-wise manner along microtubules. To resolve rotations during stepping, we used optical tweezers combined with an optical microprotractor and torsion balance using highly birefringent microspheres to directly and simultaneously measure the translocation, rotation, force, and torque generated by individual kinesin-1 motors. While, at low adenosine 5'-triphosphate (ATP) concentrations, motors did not generate torque, we found that motors translocating along microtubules at saturating ATP concentrations rotated unidirectionally, producing significant torque on the probes. Accounting for the rotational work makes kinesin a highly efficient machine. These results imply that the motor's gait follows a rotary hand-over-hand mechanism. Our method is generally applicable to study rotational and linear motion of molecular machines, and our findings have implications for kinesin-driven cellular processes.