对 Sir2 相关的短 prokaryotic Argonaute 免疫系统的四重化依赖激活
Ning Cui1, Jun-Tao Zhang1, Zhuolin Li1
1Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China.
Nature communications
|October 4, 2024
概括
作为SPARSA免疫系统的一部分的Prokaryotic Argonaute (pAgo) 蛋白质,形成四聚体来激活NADase活动. 这种机制通过耗尽NAD+并触发细胞死亡来防御入侵者.
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 生化学
背景情况:
- 细胞阿尔戈纳特蛋白 (eAgos) 使用导向RNA进行RNA沉默.
- Prokaryotic Argonaute 蛋白质 (pAgos) 赋予了对外来核酸的免疫力.
- Sir2-域关联短pAgo (SPARSA) 系统通过NAD+枯竭和细胞死亡调解 prokaryotic 免疫力,但其激活机制尚不清楚.
研究的目的:
- 为了阐明SPARSA激活的分子机制.
- 确定SPARSA组装的结构基础,指导RNA结合和NADase活动.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于确定非活性和活性SPARSA复合物的结构.
- 生物化学试验分析NADase活动并指导RNA相互作用.
主要成果:
- 克里奥-EM结构显示了非活性单体,活性四体和NAD+结合的四体SPARSA复合体.
- 短的pAgos与Sir2-APAZ形成异构体,更喜欢具有5'-AU动图的短导向RNA.
- 目标ssDNA的识别触发了SPARSA四重化,导致Sir2的重新排列和NAD+的水解.
结论:
- SPARSA激活涉及目标ssDNA诱导的四重化和NADase活性.
- 这些发现为Sir2-域相关的pAgo免疫系统提供了机械的洞察力.
- 这项研究为开发基于短时间的pAgo系统的新生物技术工具开辟了道路.
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