9kzr

Anti-CRISPR protein AcrIIA7

spinqualitylabelsall models 9kzr, resolution 2.16Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9kzr is a 4 chain structure with sequence from Phocaeicola dorei. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.16Å Ligands: MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The CRISPR-Cas9 system provides adaptive immunity against invading genetic elements through a dual-RNA-guided DNA cleavage mechanism. This system relies on the precise assembly of a ribonucleoprotein (RNP) complex composed of the Cas9 endonuclease, a CRISPR-derived RNA (crRNA), and a trans-activating CRISPR RNA (tracrRNA). Around 100 anti-CRISPR proteins that inhibit CRISPR-Cas systems have been identified, and the mechanisms by which they act are increasingly being elucidated. However, the inhibitory mechanisms of many Acrs, including AcrIIA7, remain poorly understood. Here, we present the structure of AcrIIA7 and uncover a previously unrecognized mechanism by which it inhibits Cas9 function. Structural and biochemical analyses reveal that AcrIIA7 specifically binds to tracrRNA, preventing its association with crRNA and thereby blocking formation of the active Cas9 RNP complex. This tracrRNA hijacking mechanism represents a unique strategy for CRISPR inhibition, in which an anti-CRISPR protein targets an RNA scaffold essential for Cas9 activation rather than interacting directly with the Cas9 protein. Our findings provide the first structural insight into tracrRNA-targeted anti-CRISPR activity and highlight RNA-RNA interaction interfaces as vulnerable nodes in CRISPR-Cas immunity. AcrIIA7 hijacks tracrRNA to block CRISPR-Cas system.,Lee SY, Park HH Nat Commun. 2026 Mar 14;17(1):3959. doi: 10.1038/s41467-026-70749-w. PMID:41832226 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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