Interpreting a medium-resolution model of tubulin: comparison of zinc-sheet and microtubule structure.
Interpreting a medium-resolution model of tubulin: comparison of zinc-sheet and microtubule structure.
复制标题
解释微管蛋白的中等分辨率模型：锌片和微管结构的比较。
DOI：
10.1006/jmbi.1996.0530
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Downing,KH
中科院分区：
文献类型：
--
作者：
Wolf,SG;Nogales,E;Kikkawa,M;Gratzinger,D;Hirokawa,N;Downing,KH
我们先前使用锌诱导的微管蛋白的二维结晶片的电子晶体学来构建该蛋白的中等分辨率三维（3-D）重建（在6.5 nm处）。在这里，我们提出了一个改进的模型，并扩展的解释，它与微管结构。枯草杆菌蛋白酶裂解微管蛋白的二级序列预测和投影密度图提供了关于C-末端部分的位置的信息，该部分已被建议参与微管相关蛋白的结合。锌片微管蛋白模型进行了比较，微管在两种方式;比较电子衍射从锌片电子衍射从微管，并通过对接的锌片原丝3-D模型到一个螺旋重建从冰嵌入的微管。通过将锌片原丝与轴丝原丝的重建相关联，我们将极性分配给我们模型中的原丝。极性分配，连同我们的二聚体边界模型和我们重建中α-和β-单体的分配，提供了一个微管模型，其中α-单体冠状微管的正（或快速生长）端，并在中心体中与γ-微管内分泌β-单体接触。
We previously used electron crystallography of zinc-induced two-dimen sional crystalline sheets of tubulin to construct a medium-resolution three dimensional (3-D) reconstruction (at 6.5 Å) of this protein. Here we present an improved model, and extend the interpretation to correlate it to microtubule structure. Secondary sequence predictions and projection density maps of subtilisin-cleaved tubulin provide information on the location of the C-terminal portion, which has been suggested to be involved in the binding of microtubule-associated proteins. The zinc-sheet tubulin model is compared to microtubules in two ways; comparison of electron diffraction from the zinc-sheets to electron diffraction from microtubules, and by docking the zinc-sheet protofilament 3-D model into a helical reconstruction from ice-embedded microtubules. By correlating the zinc-sheet protofilament to a reconstruction of axonemal protofila ments, we assigned polarity to the protofilament in our model. The polarity assignment, together with our model for dimer boundaries and the assignment of α- and β-monomers in our reconstruction, provides a microtubule model where the α-monomer crowns the plus- (or fast-growing) end of the microtubule and contact is made in the centrosome with γ-tubulinviathe β-monomer.