对增强剂结合蛋白的活性进行结构洞察
Mathieu Rappas1, Jorg Schumacher, Fabienne Beuron
1Department of Biological Sciences, Imperial College London, London, SW7 2AZ, UK.
概括
西格玛54-RNA聚合酶的激活剂使用ATP水解来激活转录. 这项研究揭示了PspF(1-275) 如何通过核酸依赖的形状变化结合sigma54,并使用冷EM进行鉴定.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 西格玛54-RNA聚合酶全酶控制细菌的转录启动.
- 激活蛋白对于依赖sigma54的转录是必不可少的,利用ATP水解.
- 菌体冲击蛋白F [PspF(1-275) ] 是一个关键的sigma54激活剂.
研究的目的:
- 为了阐明PSPF的结构机制 ((1-275) 与sigma54.5的相互作用.
- 了解ATP水解在激活剂-sigma54复合体形成中的作用.
- 以近原子分辨率确定激活器-sigma54复合物的结构.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于确定与sigma54.5结合的PSPF的结构.
- 将高分辨率的PspF ((1-275) 晶体结构安装到冷EM图中.
- 突变分析和在不同核酸状态下增强剂结合域的比较.
主要成果:
- 获得了PspF(1-275) -sigma54复合物的20安格斯特罗姆分辨率的冷电磁结构.
- 在PspF ((1-275) 内的两个特定循环被确定为sigma54结合的关键.
- 建议在PspF ((1-275) 中进行核酸依赖的构造变化,以促进sigma54协会.
结论:
- 这项研究为了解sigma54激活器功能提供了结构基础.
- 由ATP结合和水解驱动的形状灵活性对于激活剂-sigma54相互作用至关重要.
- 这项工作促进了对细菌转录调节机制的了解.
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