信号识别粒子受体暴露了核糖体转位素结合部位
Mario Halic1, Marco Gartmann, Oliver Schlenker
1Institute of Biochemistry, Charité, University Medical School Berlin, Monbijoustrasse 2, 10117 Berlin, Germany.
概括
信号识别粒子 (SRP) 受体结合SRP和核糖体,暴露了蛋白质向膜的关键部位. 这种相互作用在蛋白质转位过程中保持延长停止.
科学领域:
- 分子生物学分子生物学
- 结构生物学是结构生物学.
- 细胞生物学 细胞生物学
背景情况:
- 分泌和膜蛋白需要特定的准机制才能到达它们的细胞目的地.
- 信号识别粒子 (SRP) 途径对于将这些蛋白质导向到内质网膜膜至关重要.
- SRP受体促进了与SRP结合的核糖体和蛋白质转位机制 (转位子) 之间的相互作用.
研究的目的:
- 在蛋白质向过程中阐明SRP-SRP受体相互作用的结构基础.
- 以高分辨率可视化"对接复合体",以了解所涉及的分子重组.
- 确定SRP受体如何影响SRP-核糖体复杂结构.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来确定该复合物的结构.
- 获得了对接综合体的8安格斯特罗姆分辨率结构.
- 该复合体包括一个与信号识别粒子 (SRP) 结合的80S核糖体和SRP受体.
主要成果:
- 该结构揭示了SRP受体,SRP和核糖体在对接复合体中的精确排列.
- 与SRP受体的相互作用诱导了SRP的S域的构造变化.
- 在受体结合时,转位子的一个核糖体结合部位 (L23e/L35部位) 暴露在受体结合上.
- 观察到 Alu 域介导的延长停止持续存在.
结论:
- SRP受体在重组SRP-核糖体复合体中发挥着关键作用,以促进蛋白质转位.
- 对L23e/L35位点的暴露是SRP受体介导的关键步骤,准备核糖体转移到转位子.
- 这项研究为蛋白质向和膜插入的基本过程提供了原子层面的见解.
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