3opv

Crystal structure of E. Coli purine nucleoside phosphorylase Arg24Ala mutant

spinqualitylabelsall models 3opv, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3opv is a 12 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.4Å Ligands: PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DEOD_ECOLI Cleavage of guanosine or inosine to respective bases and sugar-1-phosphate molecules.[HAMAP-Rule:MF_01627] Publication Abstract from PubMed The catalytic mechanism of Escherichia coli purine nucleoside phosphorylase (PNP) is revised using site-directed mutagenesis, kinetic studies and structure determinations. The experimental evidence on the role of the particular catalytic amino acid during catalysis has not been available. Therefore, the active site mutants Arg24Ala, Asp204Ala, Asp204Asn, Arg217Ala and Asp204Ala/Arg217Ala were prepared and their kinetics and thermodynamic studies were carried out. The activity tests with natural substrates and 7-methylguanosine confirmed the earlier hypothesis, that catalysis involves protonation of the purine base at position N7 by Asp204, which is triggered by Arg217. The crystal structures of the wild type in complexes with phosphate and sulphate, respectively, and of the Arg24Ala mutant in complex with phosphate/sulphate were determined. The structural data show that previously observed conformational change is a result of the phosphate binding and its interaction with Arg24. As E. coli PNP is a promising candidate for the tumour-directed gene therapy, our results may also help to design efficient mutants useful in gene therapy. Validation of the catalytic mechanism of Escherichiacoli purine nucleoside phosphorylase by structural and kinetic studies.,Mikleusevic G, Stefanic Z, Narczyk M, Wielgus-Kutrowska B, Bzowska A, Luic M Biochimie. 2011 Jun 13. PMID:21672603 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Purine nucleoside phosphorylase 3D structures

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