2bsx: Difference between revisions
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==Overview== | ==Overview== | ||
Purine metabolism in the parasite Plasmodium has been identified as a | 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. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Purine-nucleoside phosphorylase]] | [[Category: Purine-nucleoside phosphorylase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Brannigan, J | [[Category: Brannigan, J A.]] | ||
[[Category: Brzozowski, A | [[Category: Brzozowski, A M.]] | ||
[[Category: Dodson, E | [[Category: Dodson, E J.]] | ||
[[Category: Murshudov, G | [[Category: Murshudov, G N.]] | ||
[[Category: Schnick, C.]] | [[Category: Schnick, C.]] | ||
[[Category: Wilkinson, A | [[Category: Wilkinson, A J.]] | ||
[[Category: NOS]] | [[Category: NOS]] | ||
[[Category: glycosyltransferase]] | [[Category: glycosyltransferase]] | ||
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[[Category: uridine phosphorylase]] | [[Category: uridine phosphorylase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:41:17 2008'' | ||
Revision as of 17:41, 21 February 2008
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CRYSTAL STRUCTURE OF THE PLASMODIUM FALCIPARUM PURINE NUCLEOSIDE PHOSPHORYLASE COMPLEXED WITH INOSINE
OverviewOverview
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.
About this StructureAbout this Structure
2BSX is a Single protein structure of sequence from Plasmodium falciparum with as ligand. Active as Purine-nucleoside phosphorylase, with EC number 2.4.2.1 Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
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
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