Architecture of the Xenopus nuclear pore complex revealed by three-dimensional cryo-electron microscopy.
Architecture of the Xenopus nuclear pore complex revealed by three-dimensional cryo-electron microscopy.
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三维冷冻电子显微镜揭示了爪蟾核孔复合物的结构。
DOI：
10.1083/jcb.122.1.1
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发表时间：
1993-07
影响因子：
7.8
通讯作者：
Radermacher, M
中科院分区：
文献类型：
--
作者：
Akey, C W;Radermacher, M
核孔复合体横跨核膜，在依赖ATP的核质运输过程中作为大分子转运体发挥作用。在本报告中，我们展示了膜相关的和用去垢剂提取的非洲爪蟾核孔复合体（NPC）的三维（3D）结构，通过冷冻电子显微镜在冷冻缓冲液中成像。对3D图谱中不同构象的比较表明，辐条可能具有内在的构象灵活性。当与来自负染核孔复合体3D图谱的最新数据（Hinshaw, J. E., B. O. Carragher, 和R. A. Milligan. 1992.《细胞》69:1133 - 1141）相结合时，这些观察结果提出了辐条 - 环复合体的最小结构域模型，该模型可以解释这个组装体所观察到的可塑性。此外，相邻辐条中的腔内结构域通过径向臂二聚体相互连接，形成一个腔内环，可能负责将核孔复合体锚定在核膜孔内。重要的是，核孔复合体转运体被可视化为一个在垂直于核膜的方向上横跨核孔复合体整个宽度的中央逐渐变细的圆柱体。转运体的中心位置、三部分结构和中空性质表明它可能形成一个大分子运输通道，在两端各有一个球状的门控结构域。最后，转运体在辐条内的排列形成了一组八个内部通道，这些通道可能部分负责离子和小分子在核膜上的扩散。
The nuclear pore complex spans the nuclear envelope and functions as a macromolecular transporter in the ATP-dependent process of nucleocytoplasmic transport. In this report, we present three dimensional (3D) structures for both membrane-associated and detergent- extracted Xenopus NPCs, imaged in frozen buffers by cryo-electron microscopy. A comparison of the differing configurations present in the 3D maps suggests that the spokes may possess an intrinsic conformational flexibility. When combined with recent data from a 3D map of negatively stained NPCs (Hinshaw, J. E., B. O. Carragher, and R. A. Milligan. 1992. Cell. 69:1133-1141), these observations suggest a minimal domain model for the spoke-ring complex which may account for the observed plasticity of this assembly. Moreover, lumenal domains in adjacent spokes are interconnected by radial arm dimers, forming a lumenal ring that may be responsible for anchoring the NPC within the nuclear envelope pore. Importantly, the NPC transporter is visualized as a centrally tapered cylinder that spans the entire width of the NPC, in a direction normal to the nuclear envelope. The central positioning, tripartite structure, and hollow nature of the transporter suggests that it may form a macromolecular transport channel, with a globular gating domain at each end. Finally, the packing of the transporter within the spokes creates a set of eight internal channels that may be responsible, in part, for the diffusion of ions and small molecules across the nuclear envelope.