1dbr: Difference between revisions
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{{STRUCTURE_1dbr| PDB=1dbr | SCENE= }} | |||
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'''HYPOXANTHINE GUANINE XANTHINE''' | '''HYPOXANTHINE GUANINE XANTHINE''' | ||
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[[Category: Schumacher, M A.]] | [[Category: Schumacher, M A.]] | ||
[[Category: Ullman, B.]] | [[Category: Ullman, B.]] | ||
[[Category: | [[Category: Glycosyltransferase]] | ||
[[Category: | [[Category: Purine salvage]] | ||
[[Category: | [[Category: Transferase]] | ||
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Revision as of 10:40, 2 May 2008
HYPOXANTHINE GUANINE XANTHINE
Overview
Crystal structures of substrate-free and XMP-soaked hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGXPRTase) of the opportunistic pathogen Toxoplasma gondii have been determined to 2.4 and 2.9 A resolution, respectively. HGXPRTase displays the conserved PRTase fold. In the structure of the enzyme bound to its product, a long flexible loop (residues 115-126) is located away from the active site. Comparison to the substrate-free structure reveals a striking relocation of the loop, which is poised to cover the catalytic pocket, thus providing a mechanism by which the HG(X)PRTases shield their oxocarbonium transition states from nucleophilic attack by the bulk solvent. The conserved Ser 117-Tyr 118 dipeptide within the loop is brought to the active site, completing the ensemble of catalytic residues.
About this Structure
1DBR is a Single protein structure of sequence from Toxoplasma gondii. Full crystallographic information is available from OCA.
Reference
Crystal structures of Toxoplasma gondii HGXPRTase reveal the catalytic role of a long flexible loop., Schumacher MA, Carter D, Ross DS, Ullman B, Brennan RG, Nat Struct Biol. 1996 Oct;3(10):881-7. PMID:8836106 Page seeded by OCA on Fri May 2 13:40:00 2008
