通过激进SAM酶进行甲基转移的结构基础.
Amie K Boal1, Tyler L Grove, Monica I McLaughlin
1Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
概括
激进的S-adenosyl-L-methionine (SAM) 酶RlmN和Cfr甲基化23S核糖体RNA. 这种激进的S-adenosyl-L-methionine (SAM) 酶RlmN和Cfr甲基化23S核糖体RNA. 这种激进的S-adenosyl-L-methionine (SAM) 酶RlmN和Cfr甲基化23S核糖体RNA. 结构研究显示,RlmN使用单个SAM分子和活性位点来执行其复杂的甲基化反应.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- 激进的S-adenosyl-L-methionine (SAM) 酶RlmN和Cfr对于甲基化23S核糖体RNA至关重要.
- 这种甲基化发生在腺2503的C2或C8位置,影响了核糖体功能.
研究的目的:
- 阐明RlmN利用S-adenosyl-L-methionine (SAM) 进行核糖体RNA甲基化的结构机制.
- 了解RlmN如何在单个活性部位内实现其复杂的两步甲基化过程.
主要方法:
- 采用X射线晶体学来确定RlmN的结构及其与SAM的复合物.
- 结构分析侧重于4Fe-4S集群的协调和关键残留物和SAM的定位.
主要成果:
- 晶体结构显示,一个单一的SAM分子协调RlmN中的4Fe-4S集群.
- 保存的Cys(355) 残留物是S-甲基化,位于SAM甲基组附近,表明这两个甲基化步骤都有一个共同的结合点.
- 这表明RlmN采用结构经济,通过使用一个站点来进行两种SAM-依赖反应.
结论:
- 通过利用单个SAM结合和甲基转移的活性位点,RlmN有效地催化23S核糖体RNA的两步甲基化.
- 该酶利用SAM在结构保守的结合口袋中的独特反应性,展示了一种优雅的生物化学机制.
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