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Updated: May 15, 2025

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High-Resolution Complexome Profiling by Cryoslicing BN-MS Analysis
Published on: October 15, 2019
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一个Gcn2二聚体与大型60S核糖体子单元复合的结构
Helge Paternoga1, Lu Xia2, Lyudmila Dimitrova-Paternoga1
1Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg 20146, Germany.
概括
综合应激反应 (ISR) 涉及Gcn2激酶与60S核糖体子单元的结合. 这种相互作用形成了一个备用复合体,允许在细胞应激过程中快速地将Gcn2重新分配到碰撞的核糖体中.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 结构生物学 结构生物学
背景情况:
- 综合应激反应 (ISR) 对于真核细胞适应环境压力至关重要.
- 压力会触发核糖体碰撞,激活Gcn2激酶,该激酶酸化eIF2α以调节翻译.
- Gcn2与核糖体相互作用的结构机制仍然难以捉摸.
研究的目的:
- 阐明Gcn2与核糖体60S亚单元相互作用的结构基础.
- 了解Gcn2-核糖体复合体在ISR中的作用.
- 调查Gcn2与60S子单元结合的功能影响.
主要方法:
- 酵母Gcn2和核糖体颗粒的ex vivo亲和性净化.
- 低温电子显微镜 (cryo-EM) 用于确定Gcn2-60S复合物的结构.
- 功能性研究来评估Gcn2的结合和活性.
主要成果:
- 一个冷EM结构揭示了一个酵母Gcn2二分体与60S核糖体子单元结合.
- Gcn2通过类似histidine tRNA合成酶的域进行二元化,与茎基和sarcin-ricin循环相互作用.
- Gcn2的C端域二元化并结合基转移酶中心,占据tRNA位点.
- 与60S子单元结合的Gcn2不需要Gcn1/Gcn20或导致eIF2α酸化.
- 压力诱导Gcn2从60S子单元转移到碰撞的核糖体.
结论:
- Gcn2-60S复合体代表了一个不活跃的备用状态.
- 这种复合物在应激时促进Gcn2迅速重新分配到碰撞的核糖体中.
- 这些发现为ISR和应力颗粒动态提供了结构性的见解.
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