SrmB Rescues Trapped Ribosome Assembly Intermediates
SrmB Rescues Trapped Ribosome Assembly Intermediates
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DOI：
10.1016/j.jmb.2019.12.013
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发表时间：
2020-02-14
影响因子：
5.6
通讯作者：
Williamson, James R.
中科院分区：
文献类型：
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作者：
Rabuck-Gibbons, Jessica N.;Popova, Anna M.;Williamson, James R.
RNA解旋酶在核糖体生物合成中发挥各种作用，这取决于核糖体组装途径和细胞的应激状态。然而，目前还不清楚大多数RNA解旋酶如何与核糖体组装中间体相互作用或参与其他细胞过程来调节核糖体组装。SrmB是一种DEAD盒解旋酶，在核糖体组装过程的早期起作用，尽管对其作用机制知之甚少。在这里，我们使用一个组合的定量质谱/冷冻电子显微镜的方法来详细的蛋白质库存，rRNA修饰状态，40 S核糖体的中间体，形成SrmB缺失后的结构。我们发现SrmB的结合位点不受SrmB缺失的干扰，但肽基转移酶中心，uL 7/12茎，和30 S接触位点都显示出严重的装配缺陷。考虑到现有的数据SrmB的功能和这里提出的实验，我们提出了几种机制，SrmB可以引导组装颗粒从动力学陷阱主管亚基在50 S核糖体组装过程中。(C)2019由Elsevier Ltd.出版
RNA helicases play various roles in ribosome biogenesis depending on the ribosome assembly pathway and stress state of the cell. However, it is unclear how most RNA helicases interact with ribosome assembly intermediates or participate in other cell processes to regulate ribosome assembly. SrmB is a DEAD-box helicase that acts early in the ribosome assembly process, although very little is known about its mechanism of action. Here, we use a combined quantitative mass spectrometry/cryo-electron microscopy approach to detail the protein inventory, rRNA modification state, and structures of 40S ribosomal intermediates that form upon SrmB deletion. We show that the binding site of SrmB is unperturbed by SrmB deletion, but the peptidyl transferase center, the uL7/12 stalk, and 30S contact sites all show severe assembly defects. Taking into account existing data on SrmB function and the experiments presented here, we propose several mechanisms by which SrmB could guide assembling particles from kinetic traps to competent subunits during the 50S ribosome assembly process. (C) 2019 Published by Elsevier Ltd.