8hns

Crystal structure of an anti-CRISPR protein AcrIIC4 in apo form

spinqualitylabelsall models 8hns, resolution 2.54Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8hns is a 2 chain structure with sequence from Haemophilus parainfluenzae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.54Å Ligands: GOL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A377JKY9_HAEPA Publication Abstract from PubMed 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 Haemophilus parainfluenzae 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. AcrIIC4 inhibits type II-C Cas9 by preventing R-loop formation.,Sun W, Cheng Z, Wang J, Yang J, Li X, Wang J, Chen M, Yang X, Sheng G, Lou J, Wang Y Proc Natl Acad Sci U S A. 2023 Aug;120(31):e2303675120. doi: , 10.1073/pnas.2303675120. Epub 2023 Jul 26. PMID:37494395 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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