一种抑制自身转录的抗CRISPR,同时阻断Cas9目标DNA结合的抗CRISPR
Xieshuting Deng1,2, Wei Sun1, Xueyan Li1,2
1Key Laboratory of RNA Science and Engineering, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
Nature communications
|February 28, 2024
概括
AcrIIA15是一种抗CRISPR蛋白,通过模仿DNA来抑制金黄色葡萄球菌Cas9 (SaCas9). 它的结构揭示了阻断SaCas9和通过DNA结合自我调节转录的双重功能.
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:
- AcrIIA15是一种抗CRISPR蛋白,已知可以抑制金黄色葡萄球菌Cas9 (SaCas9).
- 以前的研究表明AcrIIA15具有双重功能,但结构和生化基础尚未完全理解.
研究的目的:
- 阐明AcrIIA15对SaCas9.9的双重抑制功能的结构和生化基础.
- 了解AcrIIA15在阻断SaCas9活动和调节自身转录中的机制.
主要方法:
- 电子显微镜 (cryo-EM) 用于确定与SaCas9-sgRNA复合的AcrIIA15的结构.
- 进行X射线晶体学,以获得AcrIIA15与促进DNA结合的结构.
主要成果:
- AcrIIA15的C终端域 (CTD) 模仿双链DNA (dsDNA),阻断SaCas9.9的原空间邻基因 (PAM) 识别部位.
- AcrIIA15的N端域 (NTD) 促进了dDNA的二分化和识别.
- 通过同时结合SaCas9-sgRNA和促进DNA,AcrIIA15形成了一个超级复合体,其中包括两个Cas9s,两个CTD和一个NTD二元结合dsDNA.
结论:
- 结构和生物化学数据揭示了AcrIIA15的双重机制:CTD通过PAM模拟抑制SaCas9,NTD通过转录自调节调节DNA结合.
- 一个超级复合体的形成突出显示了反CRISPR蛋白 Cas9 和宿主DNA 之间的新型相互作用模式.
- 这些发现促进了对CRISPR-Cas系统,菌体-宿主动态以及抗CRISPR蛋白的转录调节的理解.
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