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

spinqualitylabelsall models 8fx3, resolution 1.31Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8fx3 is a 2 chain structure with sequence from Trypanosoma cruzi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.31Å Ligands: IMU Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A7J6XZA2_TRYCR 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 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phosphoribosyltransferase 3D structures

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