View source for 9w1f


==The type III CRISPR-associated deaminase in complex cA6 and ATP, State 2==
<StructureSection load='9w1f' size='340' side='right'caption='[[9w1f]], [[Resolution|resolution]] 2.84&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9w1f]] is a 7 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermoanaerobaculum_aquaticum Thermoanaerobaculum aquaticum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9W1F OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9W1F FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 2.84&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ATP:ADENOSINE-5-TRIPHOSPHATE'>ATP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=9w1f FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9w1f OCA], [https://pdbe.org/9w1f PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9w1f RCSB], [https://www.ebi.ac.uk/pdbsum/9w1f PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9w1f ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A062XY19_9BACT A0A062XY19_9BACT] 
<div style="background-color:#fffaf0;">
== 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<ref>PMID:41841492</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9w1f" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermoanaerobaculum aquaticum]]
[[Category: Kong JP]]
[[Category: Li ZX]]
[[Category: Wu WQ]]