title: Crystallization and preliminary X-ray diffraction analysis of human transcobalamin, a vitamin B12-transporting protein.
abstract: Transcobalamin is a cobalamin-binding protein in mammalian plasma that facilitates the cellular uptake of vitamin B(12). Human transcobalamin was crystallized using polyethylene glycol and ethanol as precipitants. Crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 49.04, b = 145.27, c = 164.96 A. A complete data set to 3.2 A resolution was collected from a single crystal using synchrotron radiation. Estimation of the crystal packing (V(M) = 3.2 A(3) Da(-1)) and self-rotation function analysis suggest the presence of two molecules in the asymmetric unit related by non-crystallographic twofold symmetry.
authors.affiliation: Centro di Eccellenza di Biocristallografia-Dipartimento di Scienze Chimiche, Università di Trieste, Via L. Giorgieri 1, I-34127 Trieste, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Garau
authors.forename: S N
authors.initials: SN
authors.lastname: Fedosov
authors.forename: T E
authors.initials: TE
authors.lastname: Petersen
authors.forename: S
authors.initials: S
authors.lastname: Geremia
authors.forename: L
authors.initials: L
authors.lastname: Randaccio
mesh_terms: D001692:Biological Transport; D003460:Crystallization; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014155:Transcobalamins / Q000737:chemistry* / Q000378:metabolism; D014805:Vitamin B 12 / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D014155:Transcobalamins; D014805:Vitamin B 12