一个Rrp6-RNA外基因组复合体的结构与多基因 (A) RNA结合
Elizabeth V Wasmuth1, Kurt Januszyk2, Christopher D Lima3
11] Structural Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, New York 10065, USA [2] Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA.
Nature
|July 22, 2014
概括
对于RNA处理至关重要的RNA外基因组复合体,将基质引导到Rrp6或Rrp44酶. 这项研究揭示了Rrp6的结构基础.
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:
- 细胞RNA外体是一个多个子单元复合体,负责RNA处理和降解.
- 它包括一个核心复合体 (Exo9) 和具有不同活动的催化外核核酶 (Rrp6和Rrp44).
- 通过RNA基质被引导到Rrp6的机制,以及它是否利用中央外体道,仍然不清楚.
研究的目的:
- 阐明Rrp6外核酶子单元对RNA基质接触的结构机制.
- 确定RNA外基因组复合体内涉及Rrp6的RNA结合和处理途径.
- 调查外体内核结构在引导RNA到不同催化子单元中的作用.
主要方法:
- 十个亚单元RNA外体复合体 (Exo9核+Rrp6) 的X射线晶体学,与3.3 Å分辨率的多类ARNA结合.
- 使用酵母和人类RNA外体组合物的生物化学测试和溶液研究.
- 与Rrp6活性部位和外体细胞核相对的RNA定位的结构分析.
主要成果:
- 一个晶体结构揭示了位于Exo9 S1/KH环上方的Rrp6催化域,RNA 3'端固定在Rrp6活性部位上.
- 结合RNA穿过S1/KH环的方向与观察到的Rrp44.4的方向不同.
- 溶液研究表明,RNA通往Rrp6的途径是保存的,并依赖于S1/KH环的完整性.
- 在体外,RNA路径选择到Rrp6或Rrp44似乎是随机的.
结论:
- Rrp6外基核酶利用RNA外基因组上一个独特的结合点,位于中央通道上方.
- 外体细胞核的S1/KH环在调解RNA访问Rrp6时起着至关重要的作用.
- 虽然体外路径是随机的,但体内基质向可能受到RNA结合因子的影响.
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