NEW DATA ON THE MICROTUBULE SURFACE LATTICE
NEW DATA ON THE MICROTUBULE SURFACE LATTICE
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DOI：
10.1016/0248-4900(91)90062-r
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发表时间：
1991-01-01
影响因子：
2.7
通讯作者：
WADE, RH
中科院分区：
文献类型：
--
作者：
CHRETIEN, D;WADE, RH
微管蛋白的体外聚合是蛋白质自组装的一个显著例子，因为几个密切相关的微管结构共存于聚合平台上。 冷冻电镜观察到在玻璃状冰中的未染色的体外组装微管。 新的结果大大扩展了以前的观察[47]。 在冰中，微管图像具有与原丝的数量和偏斜相关的独特对比度。 观察到的微管有12到17个原丝。 与薄切片的颗粒状材料的比较允许直接识别的图像从微管与13，14和15原丝。 一个表面晶格的住宿机制，以前提出来解释如何可变数量的原丝可以纳入基本的13原丝结构，详细描述。 我们的新的实验结果与理论预测基本一致。 只有13个原丝微管有不歪斜的原丝，这是证实了轴丝片段的观察。 结果表明，微管表面晶格是基于一个混合的包装，结合了标准的A和B晶格的功能。
The in vitro polymerisation of tubulin is a remarkable example of protein self-assembly in that several closely related microtubule structures coexist on the polymerisation plateau. Unifixed and unstained in vitro assembled microtubules were observed in vitreous ice by cryo-electron microscopy. New results are reported that considerably extend previous observations [47]. In ice, microtubule images have a distinctive contrast related to the number and skew of the protofilaments. The microtubules observed have from twelve to seventeen protofilaments. Comparison with thin sections of pelleted material allows a direct identification of images from microtubules with thirteen, fourteen and fifteen protofilaments. A surface lattice accommodation mechanism, previously proposed to explain how variable numbers of protofilaments can be incorporated into the basic thirteen protofilament structure, is described in detail. Our new experimental results are shown to be in overall agreement with the theoretical predictions. Only thirteen protofilament microtubules have unskewed protofilaments, this was confirmed by observations on axoneme fragments. The results imply that the microtubule surface lattice is based on a mixed packing which combines features of the standard A and B lattices.