A Type I-F Anti-CRISPR Protein Inhibits the CRISPR-Cas Surveillance Complex by ADP-Ribosylation
A Type I-F Anti-CRISPR Protein Inhibits the CRISPR-Cas Surveillance Complex by ADP-Ribosylation
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DOI：
10.1016/j.molcel.2020.09.015
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发表时间：
2020-11-05
期刊：
影响因子：
16
通讯作者：
Feng, Yue
中科院分区：
文献类型：
--
作者：
Niu, Yiying;Yang, Lingguang;Feng, Yue
CRISPR-Cas系统是细菌抗病毒系统，并使用抗CRISPR蛋白（Acr）来抑制这些系统。在这里，我们报告了AcrIF 11抑制I-F型CRISPR系统的新机制。我们的结构和生物化学研究表明，AcrIF 11作为一种新型的单ADP核糖基转移酶（mART）来修饰Cas 8 f亚基的N250，该亚基是识别铜绿假单胞菌crRNA引导的监视（Csy）复合物中的前间隔区相邻基序所需的残基。Csy复合物的AcrIF 11介导的ADP-核糖基化导致其双链DNA（dsDNA）结合活性完全丧失。生化研究表明，除了Cas 8 f之外，AcrIF 11还需要Cas7.6f亚基来结合和修饰Csy复合物。我们的研究不仅揭示了I型CRISPR-Cas抑制的前所未有的机制以及细菌和细菌之间的进化军备竞赛，而且还提出了在I型CRISPR-Cas系统的未来应用中设计高效调控工具的方法。
CRISPR-Cas systems are bacterial anti-viral systems, and phages use anti-CRISPR proteins (Acrs) to inactivate these systems. Here, we report a novel mechanism by which AcrIF11 inhibits the type I-F CRISPR system. Our structural and biochemical studies demonstrate that AcrIF11 functions as a novel mono-ADP-ribosyltransferase (mART) to modify N250 of the Cas8f subunit, a residue required for recognition of the protospacer-adjacent motif, within the crRNA-guided surveillance (Csy) complex from Pseudomonas aeruginosa. The AcrIF11-mediated ADP-ribosylation of the Csy complex results in complete loss of its double-stranded DNA (dsDNA) binding activity. Biochemical studies show that AcrIF11 requires, besides Cas8f, the Cas7.6f subunit for binding to and modifying the Csy complex. Our study not only reveals an unprecedented mechanism of type I CRISPR-Cas inhibition and the evolutionary arms race between phages and bacteria but also suggests an approach for designing highly potent regulatory tools in the future applications of type I CRISPR-Cas systems.