title: Calf spleen purine nucleoside phosphorylase: purification, sequence and crystal structure of its complex with an N(7)-acycloguanosine inhibitor.
abstract: Calf spleen purine nucleoside phosphorylase was purified to homogeneity and its amino acid sequence was determined. The complex of the enzyme with an N(7)-acycloguanosine inhibitor crystallized in the cubic space group P2(1)3, with unit cell dimension a = 94.02 A and one monomer in the asymmetric crystal unit. The biologically active trimer is formed by the crystallographic three-fold axis. The structure was solved by molecular replacement methods, using the model of the human erythrocyte enzyme, and refined at a resolution of 2.9 A to an R-factor of 0.21. The orientation of the inhibitor at the active site is examined in relation to the catalytic activity of the enzyme in the phosphorolysis of N(7)-beta-D-purine nucleosides.
authors.affiliation: Department of Biophysics, University Warsaw, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Bzowska
authors.forename: M
authors.initials: M
authors.lastname: Luić
authors.forename: W
authors.initials: W
authors.lastname: Schröder
authors.forename: D
authors.initials: D
authors.lastname: Shugar
authors.forename: W
authors.initials: W
authors.lastname: Saenger
authors.forename: G
authors.initials: G
authors.lastname: Koellner
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D018360:Crystallography, X-Ray; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011683:Purine-Nucleoside Phosphorylase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000648:ultrastructure; D013154:Spleen / Q000201:enzymology
chemical_list: D046911:Macromolecular Substances; D011683:Purine-Nucleoside Phosphorylase