View source for 8fx3


==Crystal structure of the Trypanosoma cruzi hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGXPRT), isoform D, bound to Immucillin-GP, showing the structure of the complete active site in its open conformation==
<StructureSection load='8fx3' size='340' side='right'caption='[[8fx3]], [[Resolution|resolution]] 1.31&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8fx3]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Trypanosoma_cruzi Trypanosoma cruzi]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8FX3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8FX3 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]] 1.31&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=IMU:PHOSPHORIC+ACID+MONO-[5-(2-AMINO-4-OXO-4,5-DIHYDRO-3H-PYRROLO[3,2-D]PYRIMIDIN-7-YL)-3,4-DIHYDROXY-PYRROLIDIN-2-YLMETHYL]+ESTER'>IMU</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=8fx3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8fx3 OCA], [https://pdbe.org/8fx3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8fx3 RCSB], [https://www.ebi.ac.uk/pdbsum/8fx3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8fx3 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A7J6XZA2_TRYCR A0A7J6XZA2_TRYCR] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Over 70 million people are currently at risk of developing Chagas Disease (CD) infection, with more than 8 million people already infected worldwide. Current treatments are limited and innovative therapies are required. Trypanosoma cruzi, the etiological agent of CD, is a purine auxotroph that relies on phosphoribosyltransferases to salvage purine bases from their hosts for the formation of purine nucleoside monophosphates. Hypoxanthine-guanine-xanthine phosphoribosyltransferases (HGXPRTs) catalyze the salvage of 6-oxopurines and are promising targets for the treatment of CD. HGXPRTs catalyze the formation of inosine, guanosine, and xanthosine monophosphates from 5-phospho-d-ribose 1-pyrophosphate and the nucleobases hypoxanthine, guanine, and xanthine, respectively. T. cruzi possesses four HG(X)PRT isoforms. We previously reported the kinetic characterization and inhibition of two isoforms, TcHGPRTs, demonstrating their catalytic equivalence. Here, we characterize the two remaining isoforms, revealing nearly identical HGXPRT activities in vitro and identifying for the first time T. cruzi enzymes with XPRT activity, clarifying their previous annotation. TcHGXPRT follows an ordered kinetic mechanism with a postchemistry event as the rate-limiting step(s) of catalysis. Its crystallographic structures reveal implications for catalysis and substrate specificity. A set of transition-state analogue inhibitors (TSAIs) initially developed to target the malarial orthologue were re-evaluated, with the most potent compound binding to TcHGXPRT with nanomolar affinity, validating the repurposing of TSAIs to expedite the discovery of lead compounds against orthologous enzymes. We identified mechanistic and structural features that can be exploited in the optimization of inhibitors effective against TcHGPRT and TcHGXPRT concomitantly, which is an important feature when targeting essential enzymes with overlapping activities.

Kinetic and Structural Characterization of Trypanosoma cruzi Hypoxanthine-Guanine-Xanthine Phosphoribosyltransferases and Repurposing of Transition-State Analogue Inhibitors.,Glockzin K, Meneely KM, Hughes R, Maatouk SW, Pina GE, Suthagar K, Clinch K, Buckler JN, Lamb AL, Tyler PC, Meek TD, Katzfuss A Biochemistry. 2023 Jul 18;62(14):2182-2201. doi: 10.1021/acs.biochem.3c00116. , Epub 2023 Jul 7. PMID:37418678<ref>PMID:37418678</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8fx3" style="background-color:#fffaf0;"></div>

==See Also==
*[[Phosphoribosyltransferase 3D structures|Phosphoribosyltransferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Trypanosoma cruzi]]
[[Category: Glockzin K]]
[[Category: Hughes R]]
[[Category: Katzfuss A]]
[[Category: Lamb AL]]
[[Category: Meek TD]]
[[Category: Meneely KM]]
[[Category: Suthagar K]]
[[Category: Tyler PC]]