Localization of the regulatory particle subunit Semi in the 26S proteasome
Localization of the regulatory particle subunit Semi in the 26S proteasome
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DOI：
10.1016/j.bbrc.2013.04.069
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发表时间：
2013-05-31
影响因子：
3.1
通讯作者：
Foerster, Friedrich
中科院分区：
文献类型：
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作者：
Bohn, Stefan;Sakata, Eri;Foerster, Friedrich
泛素-蛋白酶体系统负责调节细胞内的蛋白质降解，26S 蛋白酶体作为其执行臂。这种 2.5 MDa 复合物的分子结构最近已确定，但小的酸性亚基 Semi 除外。在这里，我们使用冷冻电子显微镜单粒子重建从具有 semi 缺失的酵母细胞中纯化的蛋白酶体，定位与 Rpn7 亚基 PCI 结构域结合的 Semi 的 C 末端螺旋。根据 26S 蛋白酶体的位点特异性交联数据推断出桥接 Rpn7 和 Rpn3 之间裂缝的 Semi N 端区域的大致位置。我们的结构研究表明，Semi 在不同环境下可以呈现不同的构象，这支持了 Semi 作为分子胶稳定 Rpn3/Rpn7 异二聚体的观点。 (C) 2013 Elsevier Inc. 保留所有权利。
The ubiquitin-proteasome system is responsible for regulated protein degradation in the cell with the 26S proteasome acting as its executive arm. The molecular architecture of this 2.5 MDa complex has been established recently, with the notable exception of the small acidic subunit Semi. Here, we localize the C-terminal helix of Semi binding to the PCI domain of the subunit Rpn7 using cryo-electron microscopy single particle reconstruction of proteasomes purified from yeast cells with semi deletion. The approximate position of the N-terminal region of Semi bridging the cleft between Rpn7 and Rpn3 was inferred based on site-specific cross-linking data of the 26S proteasome. Our structural studies indicate that Semi can assume different conformations in different contexts, which supports the idea that Semi functions as a molecular glue stabilizing the Rpn3/Rpn7 heterodimer. (C) 2013 Elsevier Inc. All rights reserved.