View source for 8z96


==Crystal structure of CrtAgo/TIR-APAZ in complex with guide DNA and 21-nt target DNA==
<StructureSection load='8z96' size='340' side='right'caption='[[8z96]], [[Resolution|resolution]] 3.36&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8z96]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermoflavifilum_thermophilum Thermoflavifilum thermophilum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8Z96 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8Z96 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]] 3.36&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=8z96 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8z96 OCA], [https://pdbe.org/8z96 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8z96 RCSB], [https://www.ebi.ac.uk/pdbsum/8z96 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8z96 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A1I7NFD7_9BACT A0A1I7NFD7_9BACT] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Short prokaryotic Argonaute and the associated TIR-APAZ (SPARTA) proteins constitute a prokaryotic immune system, mediating RNA- or DNA-guided target single-stranded DNA (ssDNA) to activate NADase activity and induce cell death by degrading NAD+ in response to invading plasmids. Although the guide RNA-mediated targeting mechanism of SPARTA has been established, the functional role and mechanisms of guide DNA-mediated SPARTA remain poorly understood. Here, we report two crystal structures of Crenotalea thermophila SPARTA complexes with 5'-phosphorylated 21-nt guide DNA and complementary target ssDNA lengths of 15 or 20 nt. The structures demonstrate specific recognition of the 5'-OH or 3'-OH groups in target DNA by SPARTA, while not recognizing the 5'-P group in guide DNA. This suggests distinct recognition models for guide DNA and guide RNA, indicating different activation mechanisms. Furthermore, these two structures reveal disparate models for recognizing guide DNA and target DNA, providing insights into the length requirement for SPARTA activation.

Structural basis of ssDNA-guided NADase activation of prokaryotic SPARTA system.,Hu R, Guo C, Liu X, Lin Y, Yang Z, Li Z, Yang Y, Ma E, Li Y, Chen J, Liu L Nucleic Acids Res. 2025 Feb 8;53(4):gkaf110. doi: 10.1093/nar/gkaf110. PMID:39997222<ref>PMID:39997222</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8z96" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermoflavifilum thermophilum]]
[[Category: Chen J]]
[[Category: Hu R]]
[[Category: Liu L]]