title: Structure of Escherichia coli uridine phosphorylase at 2.0 A.
abstract: The 2.0 A crystal structure has been determined for Escherichia coli uridine phosphorylase (UP), an essential enzyme in nucleotide biosynthesis that catalyzes the phosphorolytic cleavage of the C-N glycosidic bond of uridine to ribose-1-phosphate and uracil. The structure determination of two independent monomers in the asymmetric unit revealed the residue composition and atomic details of the apo configurations of each active site. The native hexameric UP enzyme was revealed by applying threefold crystallographic symmetry to the contents of the asymmetric unit. The 2.0 A model reveals a closer structural relationship to other nucleotide phosphorylase enzymes than was previously appreciated.
authors.affiliation: Biochemistry Department and Structural Biology Program, Weill Medical College of Cornell University, New York, NY 10021, USA.
authors.forename: F Temple
authors.initials: FT
authors.lastname: Burling
authors.forename: Ryan
authors.initials: R
authors.lastname: Kniewel
authors.forename: John A
authors.initials: JA
authors.lastname: Buglino
authors.forename: Tanya
authors.initials: T
authors.lastname: Chadha
authors.forename: Andrew
authors.initials: A
authors.lastname: Beckwith
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Lima
mesh_terms: D001051:Apoenzymes / Q000737:chemistry; D001665:Binding Sites; D018360:Crystallography, X-Ray / Q000379:methods; D004926:Escherichia coli / Q000201:enzymology*; D008958:Models, Molecular; D011487:Protein Conformation; D014543:Uridine Phosphorylase / Q000737:chemistry*
chemical_list: D001051:Apoenzymes; D014543:Uridine Phosphorylase