title: Crystallization and initial X-ray diffraction of BtuB, the integral membrane cobalamin transporter of Escherichia coli.
abstract: BtuB, the cobalamin transporter from Escherichia coli, has been overexpressed, purified and crystallized. The purified protein was solubilized in n-octyl tetraoxyethylene (C(8)E(4)) and was crystallized using sitting-drop vapor diffusion with PEG 3350 and magnesium acetate as precipitants (pH 6.5). Two crystal forms have been obtained. Crystal type I belongs to space group P3(1)21, with unit-cell parameters a = b = 81.6, c = 210.0 A, alpha = beta = 90, gamma = 120 degrees. Crystal type II belongs to space group P3(1)21, with unit-cell parameters a = b = 81.6, c = 226.0 A, alpha = beta = 90, gamma = 120 degrees. Each crystal form contains a monomer in the asymmetric unit. Diffraction for crystal type I extends to 2.0 A and diffraction for crystal type II extends to 2.7 A. Both crystal forms are suitable for structure determination.
authors.affiliation: Department of Microbiology, University of Virginia, Charlottesville, Virginia 22908, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Chimento
authors.forename: Arun K
authors.initials: AK
authors.lastname: Mohanty
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Kadner
authors.forename: Michael C
authors.initials: MC
authors.lastname: Wiener
mesh_terms: D001425:Bacterial Outer Membrane Proteins; D003001:Cloning, Molecular; D003460:Crystallization; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000737:chemistry*; D026901:Membrane Transport Proteins; D018000:Receptors, Peptide / Q000096:biosynthesis / Q000737:chemistry*; D014805:Vitamin B 12 / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D001425:Bacterial Outer Membrane Proteins; C044592:BtuB protein, E coli; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D018000:Receptors, Peptide; D014805:Vitamin B 12