title: Structure of recombinant Leishmania donovani pteridine reductase reveals a disordered active site.
abstract: Pteridine reductase (PTR1) is a potential target for drug development against parasitic Trypanosoma and Leishmania species, protozoa that are responsible for a range of serious diseases found in tropical and subtropical parts of the world. As part of a structure-based approach to inhibitor development, specifically targeting Leishmania species, well ordered crystals of L. donovani PTR1 were sought to support the characterization of complexes formed with inhibitors. An efficient system for recombinant protein production was prepared and the enzyme was purified and crystallized in an orthorhombic form with ammonium sulfate as the precipitant. Diffraction data were measured to 2.5 Å resolution and the structure was solved by molecular replacement. However, a sulfate occupies a phosphate-binding site used by NADPH and occludes cofactor binding. The nicotinamide moiety is a critical component of the active site and without it this part of the structure is disordered. The crystal form obtained under these conditions is therefore unsuitable for the characterization of inhibitor complexes.
authors.affiliation: Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland.
authors.forename: Keri L
authors.initials: KL
authors.lastname: Barrack
authors.forename: Lindsay B
authors.initials: LB
authors.lastname: Tulloch
authors.forename: Lynsey-Ann
authors.initials: LA
authors.lastname: Burke
authors.forename: Paul K
authors.initials: PK
authors.lastname: Fyfe
authors.forename: William N
authors.initials: WN
authors.lastname: Hunter
mesh_terms: D000818:Animals; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D006801:Humans; D007893:Leishmania donovani / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009249:NADP / Q000737:chemistry; D010088:Oxidoreductases / Q000737:chemistry* / Q000235:genetics; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics; D014961:X-Ray Diffraction
chemical_list: D015800:Protozoan Proteins; D011994:Recombinant Proteins; D009249:NADP; D010088:Oxidoreductases; C085592:pteridine reductase