多通道smFRET研究揭示了EF-G在核糖体上的紧构造
Jordan L Johnson1, Jacob H Steele1, Ran Lin1
1Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA.
The international journal of biochemistry & cell biology
|April 10, 2025
概括
延长因子G (EF-G) 突变揭示了它在核糖体转位期间的形状适应性. 特定突变通过将EF-G锁定到紧状态来阻碍蛋白质合成,从而提供了对eEF2调节的见解.
科学领域:
- 分子生物学分子生物学
- 生物化学 生化学
- 结构生物学 结构生物学
背景情况:
- 延长因子G (EF-G) 对于核糖体转位至关重要,但其GTP水解的功能尚不清楚.
- 在Thr56中对真核延长因子2 (eEF2) 的酸化抑制了蛋白质合成,但该机制仍然难以捉摸.
研究的目的:
- 通过单分子Förster共振能量转移 (smFRET) 来研究核糖体转移期间的EF-G形状变化.
- 探索模仿eEF2 Thr56修饰的突变对EF-G功能和构造的影响.
主要方法:
- 开发了一种多通道smFRET显微镜技术.
- 使用双标记的EF-G (Alexa 488/594) 和与核糖体结合的tRNA (Cy3) 和核糖体蛋白L27 (Cy5) 进行同时探测.
- 在转移过程中分析了野生类型和突变EF-G的构造状态.
主要成果:
- 野生类型的EF-G在核糖体结合时采用扩展形状,以促进转移,无论GTP或GDPCP存在.
- 突变EF-G (T48E,T48V) 保留了GTP/GDP结合和水解能力,但影响了Poly.Phe合成.
- 突变EF-G表现出与孤立的SRL相互作用不见的独特的紧形状,阻碍了转位.
结论:
- EF-G表现出对其在蛋白质合成中的作用至关重要的形状灵活性.
- 模仿eEF2修饰的突变诱导非功能紧状态,为eEF2调节和蛋白质合成抑制提供了机械洞察力.
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