Goodenough U W, Heuser J E
J Cell Biol. 1982 Dec;95(3):798-815. doi: 10.1083/jcb.95.3.798.
The substructure of the outer dynein arm has been analyzed in quick-frozen deep-etch replicas of Tetrahymena and Chlamydomonas axonemes. Each arm is found to be composed of five morphologically discrete components: an elliptical head; two spherical feet; a slender stalk; and an interdynein linker. The feet make contact with the A microtubule of each doublet; the stalk contacts the B microtubule; the head lies between the feet and stalk; and the linker associates each arm with its neighbor. The spatial relationships between these five components are found to be distinctly different in rigor (ATP-depleted) versus relaxed (ATP- or vanadate plus ATP-treated) axonemes, and the stalk appears to alter its affinity for the B microtubule in the relaxed state. Images of living cilia attached to Tetrahymena cells show that the relaxed configuration is adopted in vivo. We relate our observations to morphological and experimental studies reported by others and propose several models that suggest how this newly described dynein morphology may relate to dynein function.
利用嗜热四膜虫和衣藻轴丝的快速冷冻深度蚀刻复制品，对外侧动力蛋白臂的亚结构进行了分析。发现每个动力蛋白臂由五个形态上不同的组件组成：一个椭圆形头部；两个球形足部；一个细长的柄部；以及一个动力蛋白间连接体。足部与每个双联体的A微管接触；柄部与B微管接触；头部位于足部和柄部之间；连接体将每个动力蛋白臂与其相邻臂相连。发现在僵直（ATP耗尽）与松弛（ATP或钒酸盐加ATP处理）轴丝中，这五个组件之间的空间关系明显不同，并且在松弛状态下，柄部似乎改变了其对B微管的亲和力。附着在嗜热四膜虫细胞上的活纤毛图像显示，在体内采用的是松弛构型。我们将我们的观察结果与其他人报道的形态学和实验研究相关联，并提出了几个模型，这些模型表明这种新描述的动力蛋白形态可能与动力蛋白功能有何关系。
