通过NusG家族的通用调节器进行转录延长控制的结构基础
Jin Young Kang1, Rachel Anne Mooney2, Yuri Nedialkov3
1The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
Cell
|June 12, 2018
概括
普遍保存的NusG和RfaH蛋白通过稳定RNA聚合酶延长复合体来调节细菌的转录. 结构研究揭示了它们如何防止回溯以及RfaH如何专门针对操作极性抑制位点.
科学领域:
- 分子生物学
- 结构生物学
- 遗传学
背景情况:
- NusG,RfaH和Spt5是生命的所有领域中保存的基本转录延长因子.
- 细菌NusG通过防止回溯和协调终止/翻译来增强RNA聚合酶 (RNAP) 的延长.
- RfaH 是NusG的一种类型,它特别作用于操作子极性抑制器 (ops) 位点,以防止暂停.
研究的目的:
- 阐明NusG和RfaH调节RNAP延长复合体 (EC) 的结构机制.
- 了解RfaH如何赋予作战地点的特异性,并抑制暂停.
- 提供NusG/RfaH/Spt5家族蛋白质的保存功能.
主要方法:
- 使用单粒子冷电子显微镜 (cryo-EM) 来确定高分辨率结构.
- 在作战地点与NusG或RfaH相互作用的EC结构已被解决.
- 进行了比较结构分析以了解差异因子结合和功能.
主要成果:
- NusG和RfaH都通过促进上游DNA的合,抑制回溯稳定EC.
- 与NusG相比,RfaH-opsEC结构显示了对ops发针的特定识别和更严格的EC绑定.
- RfaH结合阻碍了发针诱导暂停所需的RNAP构成.
结论:
- NusG和RfaH共享一种通过DNA监护抑制回溯的共同机制.
- RfaH具有独特的功能,可以识别作战地点,并增强EC稳定性,不包括NusG.
- 这些发现的机制突显了这些基本转录调节者的保留和专业作用.
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