Molecular architecture of the 26S proteasome holocomplex determined by an integrative approach
Molecular architecture of the 26S proteasome holocomplex determined by an integrative approach
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DOI：
10.1073/pnas.1120559109
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发表时间：
2012-01-31
影响因子：
11.1
通讯作者：
Baumeister, Wolfgang
中科院分区：
文献类型：
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作者：
Lasker, Keren;Foerster, Friedrich;Baumeister, Wolfgang
26S 蛋白酶体位于泛素-蛋白酶体途径的执行端，用于控制细胞内蛋白质的降解。虽然其 20S 核心颗粒 (CP) 的结构已通过 X 射线晶体学确定，但 19S 调节颗粒 (RP) 的结构仍然难以捉摸，该颗粒负责招募底物、展开底物并将其转移到 CP 进行降解。在这里，我们描述了 26S 全复合物的分子结构，该结构是通过基于冷冻电子显微镜、X 射线晶体学、残基特异性化学交联和几种蛋白质组学技术的数据的综合方法确定的。 RP 的“盖子”（由 Rpn3/5/6/7/8/9/11/12 组成）以模块化方式组织。 Rpn3/5/6/7/9/12 形成马蹄形异源六聚体，连接到 CP 并覆盖 AAA-ATPase 模块，将 Rpn8/Rpn11 异源二聚体定位在靠近其嘴部的位置。 Rpn2 是刚性的，支撑着盖子，而 Rpn1 是构象可变的，位于 ATPase 环的外围。泛素受体 Rpn10 和 Rpn13 位于 RP 的远端部分，表明它们在复合体进化后期被招募到该复合体中。 26S 蛋白酶体的模块化结构提供了对泛素化底物降解之前事件顺序的深入了解。
The 26S proteasome is at the executive end of the ubiquitin-proteasome pathway for the controlled degradation of intracellular proteins. While the structure of its 20S core particle (CP) has been determined by X-ray crystallography, the structure of the 19S regulatory particle (RP), which recruits substrates, unfolds them, and translocates them to the CP for degradation, has remained elusive. Here, we describe the molecular architecture of the 26S holocomplex determined by an integrative approach based on data from cryoelectron microscopy, X-ray crystallography, residue-specific chemical cross-linking, and several proteomics techniques. The "lid" of the RP (consisting of Rpn3/5/6/7/8/9/11/12) is organized in a modular fashion. Rpn3/5/6/7/9/12 form a horseshoe-shaped heterohexamer, which connects to the CP and roofs the AAA-ATPase module, positioning the Rpn8/Rpn11 heterodimer close to its mouth. Rpn2 is rigid, supporting the lid, while Rpn1 is conformationally variable, positioned at the periphery of the ATPase ring. The ubiquitin receptors Rpn10 and Rpn13 are located in the distal part of the RP, indicating that they were recruited to the complex late in its evolution. The modular structure of the 26S proteasome provides insights into the sequence of events prior to the degradation of ubiquitylated substrates.