9w1f

The type III CRISPR-associated deaminase in complex cA6 and ATP, State 2

spinqualitylabelsall models 9w1f, resolution 2.84Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9w1f is a 7 chain structure with sequence from Thermoanaerobaculum aquaticum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.84Å Ligands: ATP, MG, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A062XY19_9BACT Publication Abstract from PubMed Type III CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated proteins) systems confer antiviral immunity via cyclic oligoadenylate (cOA) signaling. Here, we elucidate a cooperative bacterial defense strategy involving two cOA-activated CRISPR-associated Rossmann fold (CARF)-containing effectors, adenosine deaminase CAAD and ribonuclease Csx1, in Thermoanaerobaculum aquaticum. Genomic analyses indicate widespread co-occurrence of CRISPR-associated adenosine deaminase (CAAD) with ancillary CARF-containing effectors in type III CRISPR systems, suggesting that multiple CARF-containing proteins may contribute to a coordinated cOA-dependent defense. Biochemical and structural studies reveal the intrinsic dynamics of CAAD hexamer, and demonstrate that cA4/cA6 binding stabilizes CAAD hexamers, triggering metal-ion-dependent conversion of ATP into inosine triphosphate. Concurrently, the downstream Csx1 is exclusively activated by cA4 to cleave single-stranded RNA. Strikingly, we found that both effectors are capable of degrading cA4, suggesting that this CAAD-Csx1 pair may be cross-regulated and achieve immunity through a dual-targeting mechanism: in response to infection, Csx1 degrades viral RNA while CAAD disrupts nucleotide metabolism via ATP deamination, which can be relieved via cA4 degradation when infection has been eliminated. This study proposes an enhanced defense mechanism through coordinated activation and regulation of multiple CRISPR effectors by a single signaling molecule, unveiling unprecedented complexity in CRISPR immunoregulation. Structural and functional insights into the adenosine deaminase of the type III-B CRISPR-Cas system.,Li Z, Kong J, Wu W, Duan Y, Zhu Z, Hua C, Yan P, Cao C, Cao X, Xiao Y, Lu M, Chen M Nucleic Acids Res. 2026 Feb 24;54(5):gkag231. doi: 10.1093/nar/gkag231. PMID:41841492 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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