title: Isolation, crystallization in the macrogravitation field, preliminary X-ray investigation of uridine phosphorylase from Escherichia coli K-12.
abstract: Uridine phosphorylase (UPH) from Escherichia coli K-12 has been purified to near homogeneity from a strain harbouring the udp gene, encoding UPH, on a multicopy plasmid. UPH was purified to electrophoretic homogeneity with the specific activity 230 units/mg with a recovery of 80%, yielding 120 mg of enzyme from 3g cells. Crystals of enzyme suitable for X-ray diffraction analysis were obtained in a preparative ultracentrifuge. The packing of the molecules in the crystals may be described by the space group P2(1)2(1)2(1) with the unit cell constants a = 90.4; b = 128.8; c = 136.8 A. There is one molecule per asymmetric unit, Vm = 2.4. These crystals diffract to at least 2.5-2.7 A resolution. The hexameric structure of UPH was directly demonstrated by electron microscopy study and image processing.
authors.affiliation: Institute of Crystallography Academy of Sciences of the USSR, Moscow.
authors.forename: A M
authors.initials: AM
authors.lastname: Mikhailov
authors.forename: E A
authors.initials: EA
authors.lastname: Smirnova
authors.forename: V L
authors.initials: VL
authors.lastname: Tsuprun
authors.forename: I V
authors.initials: IV
authors.lastname: Tagunova
authors.forename: B K
authors.initials: BK
authors.lastname: Vainshtein
authors.forename: E V
authors.initials: EV
authors.lastname: Linkova
authors.forename: A A
authors.initials: AA
authors.lastname: Komissarov
authors.forename: Z Z
authors.initials: ZZ
authors.lastname: Siprashvili
authors.forename: A S
authors.initials: AS
authors.lastname: Mironov
mesh_terms: D003460:Crystallization; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D011487:Protein Conformation; D014543:Uridine Phosphorylase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D014961:X-Ray Diffraction
chemical_list: D014543:Uridine Phosphorylase