对Prp5如何校对前mRNA分支部位的结构洞察
Zhenwei Zhang1, Norbert Rigo2, Olexandr Dybkov2
1Department of Structural Dynamics, MPI for Biophysical Chemistry, Göttingen, Germany.
Nature
|August 5, 2021
概括
这项研究揭示了Prp5是如何通过间接校对分支部位来确保准确的mRNA前拼接. 在Hsh155蛋白重塑之前, 它会阻止组装, 确保保真性.
科学领域:
- 分子生物学
- 核糖核酸分裂
- 结构生物学
背景情况:
- U2小核核糖核蛋白 (snRNP) 整合到结合体A复合体对于mRNA前结合至关重要.
- 死亡盒螺旋酶Prp5促进了U2 snRNP的集成,通过一个不清楚的机制校对U2分支点螺旋.
- 了解结合体组合和忠实机制对于理解基因表达调节至关重要.
研究的目的:
- 阐明 Prp5 在结合体组装过程中校对前mRNA分支部位的机制.
- 确定预A复杂中间体的三维结构,以了解Prp5和Hsh155的作用.
- 提供结构性洞察力,了解结合体螺旋酶如何增强mRNA前结合效率.
主要方法:
- 在酵母提取物中产生前mRNA突变 (分支部腺删除或突变),以阻断结合体组合.
- 用冷电子显微镜来确定停滞前A复杂中间体的3D结构.
- 在前A复合体内对U1/U2 snRNP,Prp5和Hsh155蛋白相互作用的结构分析.
主要成果:
- 鉴定出一种含有 U2 支部位螺旋但具有开放的 Hsh155 HEAT 域的 pre- A 复合中间体.
- 对于A复合体形成所必需的U1和U2snRNP的大规模重新定位被Prp5阻断.
- Hsh155 HEAT域关闭,由与分支部腺结合触发,破坏Prp5结合的稳定性,表明间接校对.
结论:
- 在Hsh155重建之前,Prp5通过阻碍结合体组合来间接校对分支位置,确保正确的分支位置识别.
- 该结构揭示了Hsh155的构造变化释放Prp5的机制,允许结合体成熟.
- 这项研究提供了关键的结构洞察力,用于在mRNA前拼接过程中对拼接酶的忠实性机制.
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