Lattice defects in microtubules: protofilament numbers vary within individual microtubules.
Lattice defects in microtubules: protofilament numbers vary within individual microtubules.
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DOI：
10.1083/jcb.117.5.1031
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发表时间：
1992-06
影响因子：
7.8
通讯作者：
Wade, R H
中科院分区：
文献类型：
--
作者：
Chretien, D;Metoz, F;Verde, F;Karsenti, E;Wade, R H
我们已经使用玻璃化标本的冷冻电子显微镜来研究微管组装从三个循环纯化的微管蛋白（3x-微管蛋白）和非洲爪蟾卵的无细胞提取物。在体外组装的3x-微管蛋白样品中，大多数微管具有14个原丝，而在细胞提取物中，大多数微管具有13个原丝。在这两种情况下观察到微管多态性。原丝的数量可以沿单个微管沿着突然变化，通常为单倍增加，但也会出现双倍增加。对于3x-微管蛋白，增加镁浓度降低了14个原丝微管的比例，并降低了这些微管中过渡之间的平均间隔。原丝的不连续性可能对应于微管表面晶格中的位错样缺陷。
We have used cryo-electron microscopy of vitrified specimens to study microtubules assembled both from three cycle purified tubulin (3x- tubulin) and in cell free extracts of Xenopus eggs. In vitro assembled 3x-tubulin samples have a majority of microtubules with 14 protofilaments whereas in cell extracts most microtubules have 13 protofilaments. Microtubule polymorphism was observed in both cases. The number of protofilaments can change abruptly along individual microtubules usually by single increments but double increments also occur. For 3x-tubulin, increasing the magnesium concentration decreases the proportion of 14 protofilament microtubules and decreases the average separation between transitions in these microtubules. Protofilament discontinuities may correspond to dislocation-like defects in the microtubule surface lattice.