title: Purification and crystallization of Escherichia coli oligoribonuclease.
abstract: Oligoribonuclease (Orn) is an essential 3'-to-5' hydrolytic exoribonuclease which degrades short oligoribonucleotides to 5' mononucleotides. Escherichia coli Orn has been crystallized under several different conditions using ammonium sulfate, sodium citrate and sodium acetate as precipitants. Both native and selenomethionine-labeled oligoribonuclease (SeMet-Orn) can be crystallized at room temperature in 1.4-1.55 M sodium citrate. The SeMet-Orn crystals diffract to 2.2 A resolution and belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 70.43, b = 72.87, c = 147.76 A, and two dimers in the asymmetric unit. When grown in the presence of manganese, a second crystal form (Mn-SeMet-Orn) was obtained containing a single dimer per asymmetric unit (P2(1)2(1)2(1); a = 63.74, b = 74.31, c = 74.19 A). Finally, a hexagonal crystal form was obtained using sodium acetate as a precipitant (a = 91.5, b = 91.5, c = 111.1 A). This crystal (Zn-ApUp-Orn) belongs to the P6(5) space group and has three oligoribonuclease molecules per asymmetric unit.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, PO Box 016129, Miami, FL 33101-6129, USA.
authors.forename: Tristan J
authors.initials: TJ
authors.lastname: Fiedler
authors.forename: Helen A
authors.initials: HA
authors.lastname: Vincent
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Zuo
authors.forename: Orit
authors.initials: O
authors.lastname: Gavrialov
authors.forename: Arun
authors.initials: A
authors.lastname: Malhotra
mesh_terms: D003001:Cloning, Molecular; D003460:Crystallization / Q000379:methods; D018360:Crystallography, X-Ray; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D005095:Exoribonucleases / Q000737:chemistry* / Q000235:genetics; D008345:Manganese
chemical_list: D029968:Escherichia coli Proteins; D008345:Manganese; D005095:Exoribonucleases; C094587:oligoribonuclease