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-Structure paper
タイトル | AcrIIC4 inhibits type II-C Cas9 by preventing R-loop formation. |
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ジャーナル・号・ページ | Proc Natl Acad Sci U S A, Vol. 120, Issue 31, Page e2303675120, Year 2023 |
掲載日 | 2023年7月26日 |
![]() | Wei Sun / Zhi Cheng / Jiuyu Wang / Jing Yang / Xueyan Li / Jinlong Wang / Minxuan Chen / Xiaoqi Yang / Gang Sheng / Jizhong Lou / Yanli Wang / ![]() |
PubMed 要旨 | Anti-CRISPR (Acr) proteins are encoded by phages and other mobile genetic elements and inhibit host CRISPR-Cas immunity using versatile strategies. AcrIIC4 is a broad-spectrum Acr that inhibits the ...Anti-CRISPR (Acr) proteins are encoded by phages and other mobile genetic elements and inhibit host CRISPR-Cas immunity using versatile strategies. AcrIIC4 is a broad-spectrum Acr that inhibits the type II-C CRISPR-Cas9 system in several species by an unknown mechanism. Here, we determined a series of structures of Cas9 (HpaCas9)-sgRNA in complex with AcrIIC4 and/or target DNA, as well as the crystal structure of AcrIIC4 alone. We found that AcrIIC4 resides in the crevice between the REC1 and REC2 domains of HpaCas9, where its extensive interactions restrict the mobility of the REC2 domain and prevent the unwinding of target double-stranded (ds) DNA at the PAM-distal end. Therefore, the full-length guide RNA:target DNA heteroduplex fails to form in the presence of AcrIIC4, preventing Cas9 nuclease activation. Altogether, our structural and biochemical studies illuminate a unique Acr mechanism that allows DNA binding to the Cas9 effector complex but blocks its cleavage by preventing R-loop formation, a key step supporting DNA cleavage by Cas9. |
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手法 | EM (単粒子) / X線回折 |
解像度 | 2.54 - 3.41 Å |
構造データ | EMDB-34919, PDB-8hnv: ![]() PDB-8hns: ![]() PDB-8hnt: ![]() PDB-8hnw: |
化合物 | ![]() ChemComp-GOL: ![]() ChemComp-HOH: |
由来 |
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![]() | ANTIMICROBIAL PROTEIN / anti-CRISPR protein / cleavage inhibition / dimer / IMMUNE SYSTEM / Cas9 / REC lobe / HYDROLASE-RNA-ANTIMICROBIAL PROTEIN complex / dsDNA |