View source for 8jkz


==Cryo-EM structure of the prokaryotic SPARSA system complex==
<StructureSection load='8jkz' size='340' side='right'caption='[[8jkz]], [[Resolution|resolution]] 3.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8jkz]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Geobacter_sulfurreducens Geobacter sulfurreducens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8JKZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8JKZ 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]] 3.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</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=8jkz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8jkz OCA], [https://pdbe.org/8jkz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8jkz RCSB], [https://www.ebi.ac.uk/pdbsum/8jkz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8jkz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q74DF6_GEOSL Q74DF6_GEOSL] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Argonaute (Ago) proteins are ubiquitous across all kingdoms of life. Eukaryotic Agos (eAgos) use small RNAs to recognize transcripts for RNA silencing in eukaryotes. In contrast, the functions of prokaryotic counterparts (pAgo) are less well known. Recently, short pAgos in conjunction with the associated TIR or Sir2 (SPARTA or SPARSA) were found to serve as antiviral systems to combat phage infections. Herein, we present the cryo-EM structures of nicotinamide adenine dinucleotide (NAD(+))-bound SPARSA with and without nucleic acids at resolutions of 3.1 A and 3.6 A, respectively. Our results reveal that the APAZ (Analogue of PAZ) domain and the short pAgo form a featured architecture similar to the long pAgo to accommodate nucleic acids. We further identified the key residues for NAD(+) binding and elucidated the structural basis for guide RNA and target DNA recognition. Using structural comparisons, molecular dynamics simulations, and biochemical experiments, we proposed a putative mechanism for NAD(+) hydrolysis in which an H186 loop mediates nucleophilic attack by catalytic water molecules. Overall, our study provides mechanistic insight into the antiphage role of the SPARSA system.

Structural basis of antiphage immunity generated by a prokaryotic Argonaute-associated SPARSA system.,Zhen X, Xu X, Ye L, Xie S, Huang Z, Yang S, Wang Y, Li J, Long F, Ouyang S Nat Commun. 2024 Jan 11;15(1):450. doi: 10.1038/s41467-023-44660-7. PMID:38200015<ref>PMID:38200015</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8jkz" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Geobacter sulfurreducens]]
[[Category: Large Structures]]
[[Category: Long F]]
[[Category: Xu X]]
[[Category: Zhen X]]