非平均的单分子三级结构通过单粒子冷电子断层扫描揭示了RNA的自我折叠
Jianfang Liu1, Ewan K S McRae2,3, Meng Zhang1,4
1The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Nature communications
|October 21, 2024
概括
单个粒子冷电子断层扫描 (IPET) 揭示了RNA折叠的景观. 这种方法捕获多种RNA原形6螺旋束形状,包括中间和紧状态,没有平均值.
科学领域:
- 结构生物学 结构生物学
- 生物物理学的生物物理.
- RNA折叠的动力学
背景情况:
- 由于分辨率范围的权衡,研究大规模的RNA构造变化具有挑战性.
- RNA自我折叠涉及复杂的动态过程,这些过程很难从结构上捕获.
研究的目的:
- 为了研究设计的RNA原形6螺旋束与扣螺旋 (6HBC) 的转录后自我折叠路径.
- 在没有平均或固定的情况下可视化和分析单个RNA粒子结构,以了解折叠中间体.
主要方法:
- 用单个粒子冷电子断层扫描 (IPET) 来捕获高分辨率的3D密度图.
- 数据采集参数被优化为低电子剂量 (≤168e-Å-2),以保持原生结构.
- 重建了120个单独的RNA粒子,达到2335 Å (FSC 0.5) 的分辨率.
主要成果:
- 在120个重建中的每一个中都发现了独特的RNA螺旋和独特的三级结构.
- 统计分析证实了两个已知的形状,并揭示了折叠状态的频谱.
- 观察到6HBC的动力捕获,中间状态和高度紧缩状态.
结论:
- 通过IPET,可以在折叠过程中对单个RNA分子进行详细的结构分析.
- 该研究阐明了6HBC的成熟折叠景观,由螺旋螺旋紧缩驱动.
- 这种方法提供了关于RNA自我折叠和形状异质性的动态性质的见解.
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