1sq6 | pdb_00001sq6

Plasmodium falciparum homolog of Uridine phosphorylase/Purine nucleoside phosphorylase

spinqualitylabelsall models 1sq6, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1sq6 is a 1 chain structure with sequence from Plasmodium falciparum 3D7. 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: MSE, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Purine metabolism in the parasite Plasmodium has been identified as a promising target for antimalarial therapies. Purine nucleoside phosphorylase (PNP) is part of a salvage pathway for the biosynthesis of purines, which are essential for parasite survival. Two crystal structures of PNP from Plasmodium falciparum (PfPNP) in two space groups, each with a single subunit in the asymmetric unit, are described here. One structure, refined to 2.4 A, has an empty nucleoside-binding site and a sulfate ion bound in the phosphate-binding pocket. The second structure, refined to 2.0 A, has the substrate inosine bound to the active centre. Structure comparison reveals alterations in the active site upon ligand binding. The new structures presented here specifically highlight the likely roles of Asp206 and two loops flanking the active site: the beta7-alpha6 loop (residues approximately 161-169) and the beta9-alpha8 loop (residues approximately 208-223). Comparison with PNP in complex with transition-state inhibitors suggests that the purine substrate moves towards the phosphate substrate, rather than vice versa, upon forming the transition state. The single-substrate-containing PfPNP structures also appear to be more flexible than PfPNP bound to inhibitors. Together, these structures serve as a basis for better understanding of ligand binding and mechanism that can be further exploited to optimize the specificity of anti-PfPNP drugs. Structures of Plasmodium falciparum purine nucleoside phosphorylase complexed with sulfate and its natural substrate inosine.,Schnick C, Robien MA, Brzozowski AM, Dodson EJ, Murshudov GN, Anderson L, Luft JR, Mehlin C, Hol WG, Brannigan JA, Wilkinson AJ Acta Crystallogr D Biol Crystallogr. 2005 Sep;61(Pt 9):1245-54. Epub 2005, Aug 16. PMID:16131758 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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