View source for 7pqa


==Crystal Structure of the Ring Nuclease 0811 mutant-S12G/K169G from Sulfolobus islandicus (Sis0811)==
<StructureSection load='7pqa' size='340' side='right'caption='[[7pqa]], [[Resolution|resolution]] 2.04&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7pqa]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Sulfolobus_islandicus_REY15A Sulfolobus islandicus REY15A]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7PQA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7PQA FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.04&#8491;</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=7pqa FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7pqa OCA], [https://pdbe.org/7pqa PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7pqa RCSB], [https://www.ebi.ac.uk/pdbsum/7pqa PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7pqa ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/F0NH89_SULIR F0NH89_SULIR] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Type III CRISPR-Cas effector systems detect foreign RNA triggering DNA and RNA cleavage and synthesizing cyclic oligoadenylate molecules (cA) in their Cas10 subunit. cAs act as a second messenger activating auxiliary nucleases, leading to an indiscriminate RNA degradation that can end in cell dormancy or death. Standalone ring nucleases are CRISPR ancillary proteins which downregulate the strong immune response of Type III systems by degrading cA. These enzymes contain a CRISPR-associated Rossman-fold (CARF) domain, which binds and cleaves the cA molecule. Here, we present the structures of the standalone ring nuclease from Sulfolobus islandicus (Sis) 0811 in its apo and post-catalytic states. This enzyme is composed by a N-terminal CARF and a C-terminal wHTH domain. Sis0811 presents a phosphodiester hydrolysis metal-independent mechanism, which cleaves cA4 rings to generate linear adenylate species, thus reducing the levels of the second messenger and switching off the cell antiviral state. The structural and biochemical analysis revealed the coupling of a cork-screw conformational change with the positioning of key catalytic residues to proceed with cA4 phosphodiester hydrolysis in a non-concerted manner.

Structural basis of cyclic oligoadenylate degradation by ancillary Type III CRISPR-Cas ring nucleases.,Molina R, Jensen ALG, Marchena-Hurtado J, Lopez-Mendez B, Stella S, Montoya G Nucleic Acids Res. 2021 Dec 2;49(21):12577-12590. doi: 10.1093/nar/gkab1130. PMID:34850143<ref>PMID:34850143</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7pqa" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Sulfolobus islandicus REY15A]]
[[Category: Jensen ALG]]
[[Category: Lopez-Mendez B]]
[[Category: Marchena-Hurtado J]]
[[Category: Molina R]]
[[Category: Montoya G]]
[[Category: Stella S]]