The structure of dynein-c by negative stain electron microscopy
The structure of dynein-c by negative stain electron microscopy
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DOI：
10.1016/j.jsb.2003.10.005
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发表时间：
2004-04-01
影响因子：
3
通讯作者：
Knight, PJ
中科院分区：
文献类型：
--
作者：
Burgess, SA;Walker, ML;Knight, PJ
动力蛋白ATPase在其重链的运动区内含有六个串联的AAA模块。需要更多的序列区域来形成一个功能性的ATPase，先前的研究表明，它形成了七个或八个亚域，排列在环形或中空球中。最近的六个AAA模块的同源模型表明，这些模块形成了一个环。因此，子域的数量和安排仍然不确定。我们展示了动力蛋白-c负染的二维投影图像，揭示了其结构的新细节。最初的电子冷冻显微镜显示出类似的整体形态。该分子由三个结构域组成：茎、头和茎。在没有核苷酸的情况下，头部有七个密度叶，形成一个不对称的环。第八叶从这个七聚体环的一侧伸出，似乎加入了细长的货物结合茎。近端的茎是灵活的，茎也是如此，这表明它们在电机中充当顺应元件。一项对功率卒中前后构象的新分析表明，它们的灵活性对微管结合区域的空间分布以及功率卒中大小的潜在范围产生了综合影响。我们提出并比较了动力蛋白结构的两种替代模型。(C)2003 Elsevier Inc.保留所有权利。
Dynein ATPases contain six concatenated AAA modules within the motor region of their heavy chains. Additional regions of sequence are required to form a functional ATPase, which a previous study suggested forms seven or eight subdomains arranged in either a ring or hollow sphere. A more recent homology model of the six AAA modules suggests that these form a ring. Therefore both the number and arrangement of subdomains remain uncertain. We show two-dimensional projection images of dynein-c in negative stain which reveal new details of its structure. Initial electron cryomicroscopy shows a similar overall morphology. The molecule consists of three domains: stem, head, and stalk. In the absence of nucleotide the head has seven lobes of density forming an asymmetric ring. An eighth lobe protrudes from one side of this heptameric ring and appears to join the elongated cargo-binding stem. The proximal stem is flexible, as is the stalk, suggesting that they act as compliant elements within the motor. A new analysis of pre- and post-power stroke conformations shows the combined effect of their flexibility on the spatial distribution of the microtubule-binding domain and therefore the potential range of power stroke sizes. We present and compare two alternative models of the structure of dynein. (C) 2003 Elsevier Inc. All rights reserved.