1pr4
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Escherichia coli Purine Nucleoside Phosphorylase Complexed with 9-beta-D-ribofuranosyl-6-methylthiopurine and Phosphate/Sulfate
OverviewOverview
Purine nucleoside phosphorylase catalyzes reversible phosphorolysis of, purine nucleosides and 2'-deoxypurine nucleosides to the free base and, ribose (or 2'-deoxyribose) 1-phosphate. Whereas the human enzyme is, specific for 6-oxopurine ribonucleosides, the Escherichia coli enzyme, accepts additional substrates including 6-oxopurine ribonucleosides, 6-aminopurine ribonucleosides, and to a lesser extent purine arabinosides., These differences have been exploited in a potential suicide gene therapy, treatment for solid tumors. In an effort to optimize this suicide gene, therapy approach, we have determined the three-dimensional structure of, the E. coli enzyme in complex with 10 nucleoside analogs and correlated, the structures with kinetic measurements and computer modeling. These, studies explain the preference of the enzyme for ribose sugars, show, increased flexibility for active site residues Asp204 and Arg24, and, suggest that interactions involving the 1- and 6-positions of the purine, and the 4'- and 5'-positions of the ribose provide the best opportunities, to increase prodrug specificity and enzyme efficiency.
About this StructureAbout this Structure
1PR4 is a Single protein structure of sequence from Escherichia coli, and escherichia coli o157:h7 with PO4 and MTP as ligands. Active as Purine-nucleoside phosphorylase, with EC number 2.4.2.1 Full crystallographic information is available from OCA.
ReferenceReference
Structural basis for substrate specificity of Escherichia coli purine nucleoside phosphorylase., Bennett EM, Li C, Allan PW, Parker WB, Ealick SE, J Biol Chem. 2003 Nov 21;278(47):47110-8. Epub 2003 Aug 21. PMID:12937174
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