Sandbox Reserved 342

This Sandbox is Reserved from January 10, 2010, through April 10, 2011 for use in BCMB 307-Proteins course taught by Andrea Gorrell at the University of Northern British Columbia, Prince George, BC, Canada.

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spinqualitylabelsall models PDB ID 1a96 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
1a96, resolution 2.00Å ()
Ligands:	, , ,
Gene:	GPT (Escherichia coli)
Activity:	Xanthine phosphoribosyltransferase, with EC number 2.4.2.22
Structural annotation: Resources: CATH : 1A96A00, 1A96B00, 1A96C00, 1A96D00 InterPro : Ipr002375, Ipr000836 Pfam : PF00156 SCOP : d1a96a_, d1a96b_, d1a96c_, d1a96d_ UniProt : P0A9M5
Functional annotation: Cellular component: cytoplasm Biological process: purine ribonucleoside salvage nucleoside metabolic process Molecular function: magnesium ion binding transferase activity protein binding xanthine phosphoribosyltransferase activity metal ion binding transferase activity, transferring glycosyl groups
Evolutionary conservation: Toggle Conservation Colors: Rows = identical sequences: Further Information: Caveats, Explanation, Complete Results at ConSurfDB
Resources:	FirstGlance, OCA, RCSB, PDBsum
Coordinates:	save as pdb, mmCIF, xml

IntroductionIntroduction

Xanthine-guanine Phosphoribosyltansferase (XGPRT) is one of three purine phosphoribosyltransferases (PRTases) that are part of the purine salvage pathway in Escherichia coli; the other two PRTases in the pathway are HPRT and APRT

StructureStructure

PRTase structures fall into two groups, type I and Type II. XGTPase has a conserved sequence,, which is called the PRib-PP (5-phospho-a-D-ribosyl-1-pyrophosphate) binding site. This binding site features two adjacent acidic residues, which are surrounded by hydrophobic residues. There is a five-stranded b-sheet surrounded by three or four a-helices that creates a conserved structural core containing the PRib-PP binding site. Another region of the sequence in XGTPase forms a lobe, which is involved in substrate recognition.

FunctionFunction

XGRT is an enzyme that catalyzes the conversion of guanine, xanthine, and sometimes hypoxanthine, to GMP, XMP, and IMP .

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MECHANISMMECHANISM

CatalysisCatalysis

Magnesium and other divalent cations are necessary for catalysis.