Hynes T R, Block S M, White B T, Spudich J A
Cell. 1987 Mar 27;48(6):953-63. doi: 10.1016/0092-8674(87)90704-5.
We have used the Nitella-based movement assay to localize the site of force production in myosin. Methods were developed to use nonfilamentous myosin or proteolytic fragments of myosin in place of the thick filaments used in the original assay. In the experiments described here, the tail of myosin or its subfragments is anchored via antibodies to the surface of small particles. Nonfilamentous myosin or its subfragments move along Nitella actin cables at speeds similar to those obtained with filamentous myosin. We generated short HMM, a myosin fragment containing the heads and only 400 A of the tail. Although short HMM lacks the "hinge" region proposed by Harrington to be the site of force generation, and is incapable of forming thick filaments, it moves along actin at speeds above 1 micron/sec. Therefore, neither a thick filament nor the carboxy-terminal 1100 A of the tail is required for movement along actin. The results indicate that force production occurs in or near the myosin heads.
我们已使用基于丽藻的运动分析方法来定位肌球蛋白中力产生的部位。已开发出一些方法，用非丝状肌球蛋白或肌球蛋白的蛋白水解片段替代原始分析中使用的粗肌丝。在本文所述的实验中，肌球蛋白的尾部或其亚片段通过抗体固定在小颗粒的表面。非丝状肌球蛋白或其亚片段沿着丽藻肌动蛋白丝移动的速度与丝状肌球蛋白的速度相似。我们制备了短的重链肌球蛋白（HMM），这是一种肌球蛋白片段，包含头部和仅400埃的尾部。尽管短HMM缺乏哈林顿提出的作为力产生部位的“铰链”区域，并且无法形成粗肌丝，但它能以高于1微米/秒的速度沿着肌动蛋白移动。因此，沿着肌动蛋白移动既不需要粗肌丝，也不需要尾部的羧基末端1100埃。结果表明，力产生发生在肌球蛋白头部或其附近。
