对核糖体组装因子Nep1,一种N1特异性的伪尿素甲基转移酶的结构分析揭示了机理性见解
Sayan Saha1, Shankar Prasad Kanaujia1
1Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, India.
The FEBS journal
|February 7, 2025
概括
核细胞必需蛋白1 (Nep1) 对于核糖体生物生成至关重要,催化特定RNA甲基化. 结构研究揭示了其独特的折叠和同位体性质,这对其在古生物中的功能至关重要.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 分子生物学分子生物学
背景情况:
- 核核基本蛋白1 (Nep1) 是一种核糖体RNA甲基转移酶,对于真核生物和古生物中小核糖体亚单元的形成至关重要.
- 尼普1利用一种依赖于S-adenosyl-L-methionine (SAM) 的SpoU-TrmD (SPOUT) 折叠来催化小子单元 (SSU) rRNA上的伪尿素甲基化.
- 功能障碍的Nep1与人类发育障碍和酵母菌生长障碍有关,这突显了它在核糖体生物生成中的关键作用.
研究的目的:
- 为了阐明Pyrococcus horikoshii (PhNep1) 中核细胞基本蛋白1 (Nep1) 的结构特征.
- 为了研究Nep1的辅因子结合和同质化过程的结构基础.
- 了解Nep1介导的RNA甲基化机制.
主要方法:
- 采用X射线晶体学,确定了PhNep1在Apo和Holo形式中的结构.
- 结构分析的重点是PhNep1.1的折叠,辅因子结合部位和寡合体状态.
- 进行了体外测试,以评估Nep1的RNA甲基化特异性.
主要成果:
- PhNep1的晶体结构揭示了SPOUT域特有的α/β折叠与三叶草结,以及新的扩展.
- PhNep1 形成了一个同极体,由子单元间的键和疏水性相互作用稳定.
- 辅因子结合部位呈现出预制的口袋,而PhNep1在一个保存的伪尿素部位特别甲基化16SrRNA.
结论:
- PhNep1 呈现出独特的结构架构,包括新的扩展和预制的辅因子结合口袋.
- 在二次接口上由保存的氨酸残留物稳定的同体化对于Nep1-RNA复合物的稳定性至关重要.
- 这些发现提供了对Nep1在古人类核糖体生物发生和RNA修饰中的重要作用的结构性见解.
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