通过U6小核RNA的金属离子协调有助于spliceosome中的催化
S L Yean1, G Wuenschell, J Termini
1Department of Molecular Biology, Beckman Research Institute of the City of Hope, Duarte, California 91010-3011, USA.
Nature
|December 29, 2000
概括
结合体中的小核RNA (snRNA) 对于前传递 RNA 拼接至关重要. 这项研究揭示了U6 snRNA协调了催化金属离子,这对于结合体组的必不可少.
科学领域:
- 分子生物学分子生物学
- 在RNA生物学,RNA生物学.
- 生物化学 生物化学
背景情况:
- 前传递 RNA 拼接是通过 spliceosome 内的两个连续的-转化反应发生的.
- 小核RNAs (snRNAs) 在spliceosome中的催化作用仍然未解决.
- 结合体作为金属酶起作用,因此需要对金属离子通过snRNAs协调的研究.
研究的目的:
- 为了确定snRNA是否协调了spliceosome中的催化金属离子.
- 研究U6 snRNA在金属离子协调和结合体催化活性中的作用.
主要方法:
- 通过在核酸U80.0上用硫代替非桥接氧的U6 snRNA的位点定向突变发生.
- 用修改的U6 snRNA.复合合体的复合.
- 使用不同的双价金属离子 (Mg2+和Mn2+) 测试spliceosome的催化活性.
主要成果:
- 在U80 (U6/sU80) 处以硫替代的U6 snRNA重构了具有Mg2+的无活性拼接体.
- 添加Mn2+挽救了U6/sU80(Sp) 结合体中的催化活性,但没有U6/sU80(Rp).
- 2+具有竞争性的抑制Mn2+救援反应,表明一个保存的金属结合点.
结论:
- 酵母U6 snRNA直接协调一个金属离子,这对于spliceosome催化活性至关重要.
- 这种由U6 snRNA进行的金属离子协调支持了结合体内的RNA催化假设.
- 在U6/U80的金属结合部位表现出改变的金属离子要求,这表明在拼接过程中发生了动态结构变化.
相关概念视频
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