View source for 7dc9


==The structure of the Arabidopsis thaliana guanosine deaminase mutant E82Q complex with guanosine==
<StructureSection load='7dc9' size='340' side='right'caption='[[7dc9]], [[Resolution|resolution]] 1.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7dc9]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7DC9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7DC9 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]] 1.7&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GMP:GUANOSINE'>GMP</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=7dc9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7dc9 OCA], [https://pdbe.org/7dc9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7dc9 RCSB], [https://www.ebi.ac.uk/pdbsum/7dc9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7dc9 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GSDA_ARATH GSDA_ARATH] Catalyzes the hydrolytic deamination of guanosine, producing xanthosine and ammonia. Deaminates exclusively guanosine and 2'-deoxyguanosine but no other aminated purines, pyrimidines, or pterines. Deamination of guanosine by GSDA is the only source of xanthosine production in Arabidopsis.<ref>PMID:24130159</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Guanosine deaminase (GSDA) in plants specifically deaminates (de)guanosine to produce xanthosine with high specificity, which is further converted to xanthine, a key intermediate in purine metabolism and nitrogen recycling. We solved GSDA's structures from Arabidopsis thaliana in the free and ligand-bound forms at high resolutions. Unlike GDA, the enzyme employs a single-proton shuttle mechanism for catalysis and both the substrate and enzyme undergo structural rearrangements. The last fragment of the enzyme loops back and seals the active site, and the substrate rotates during the reaction, both essential to deamination. We further identified more substrates that could be employed by the enzyme and compare it with other deaminases to reveal the recognition differences of specific substrates. Our studies provide insight into this important enzyme involved in purine metabolism and will potentially aid in the development of deaminase-based gene-editing tools.

The C-terminal loop of Arabidopsis thaliana guanosine deaminase is essential to catalysis.,Jia Q, Zeng H, Li H, Xiao N, Tang J, Gao S, Zhang J, Xie W Chem Commun (Camb). 2021 Sep 23;57(76):9748-9751. doi: 10.1039/d1cc03042f. PMID:34477187<ref>PMID:34477187</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7dc9" style="background-color:#fffaf0;"></div>

==See Also==
*[[Deaminase 3D structures|Deaminase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Arabidopsis thaliana]]
[[Category: Large Structures]]
[[Category: Jia Q]]
[[Category: Xie W]]
[[Category: Zeng H]]