通过抗CRISPR蛋白AcrIIA2626抑制SpyCas9的结构基础
Scott Bailey1, Iris Zheng1, Brian Learn1
1Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States.
The Biochemical journal
|January 19, 2026
概括
菌体使用像AcrIIA26这样的抗CRISPR (Acr) 蛋白来阻止CRISPR-Cas9的DNA向. 这项研究揭示了AcrIIA26使用双重机制通过阻断DNA结合和防止激活来抑制Streptococcus pyogenes Cas9 (SpyCas9).
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 遗传学 是一个遗传学.
背景情况:
- 克里斯普尔-卡斯9系统为 Prokaryotes 提供了对侵入 DNA 的适应性免疫力.
- 抗CRISPR (Acr) 蛋白已经在菌体中进化,以抵消CRISPR-Cas9活动.
- 在此之前,AcrIIA26抑制Streptococcus pyogenes Cas9 (SpyCas9) 的机制尚不清楚.
研究的目的:
- 阐明AcrIIA26抑制SpyCas9.9的分子机制.
- 为了确定AcrIIA26-SpyCas9-sgRNA复合物的结构.
主要方法:
- 低温电子显微镜 (cryo-EM) 在3.0 Å分辨率.
- 位点定向突变发生,以确认关键相互作用.
主要成果:
- 冷-EM结构揭示了AcrIIA26具有具有两个螺旋束的新折叠.
- 一个捆绑模仿DNA阻止SpyCas9的PAM识别,抑制DNA结合.
- 另一束可以防止Cas9激活所需的形状变化.
结论:
- 对于SpyCas9.9来说,AcrIIA26采用了双重抑制机制.
- Acrs已经趋同进化,以准PAM识别,这是一个关键的Cas9漏洞.
- 这些发现有助于设计用于基因组编辑的Cas9关闭开关.
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