title: Purification and preliminary X-ray studies on hen serotransferrin in apo- and holo-forms.
abstract: Serum transferrins are monomeric glycoproteins with a molecular mass of around 80 kDa, that transport iron to cells via receptor-mediated endocytosis. Although both serum transferrins (STfs) and ovotransferrins (OTfs) are derived from the same gene in aves, the ovotransferrins do not transport iron in vivo. Crystal structures of OTf have been solved, in contrast no three-dimensional structure of avian STf have been determined as yet. Here we report the purification, crystallization, and preliminary crystallographic studies of the hen STf both in apo- (iron free) and holo- (iron loaded) forms. The hen STf has been purified to homogeneity by hydrophobic interaction chromatography. Both the apo- and holo-forms were crystallized by hanging drop vapor diffusion method at 277 K. The apo-crystals diffract to a resolution of 3.0 A and belong to the space group P4(3)2(1)2 with unit cell parameters a=b=90.5 and c=177.9 A. The holo-crystals diffract to a resolution of 2.8 A and belong to space group P2(1) with a=72.8, b=59.6, c=88.2 A, and beta=95.7 degrees.
authors.affiliation: Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India.
authors.forename: Debi
authors.initials: D
authors.lastname: Choudhury
authors.forename: Piyali Guha
authors.initials: PG
authors.lastname: Thakurta
authors.forename: Rakhi
authors.initials: R
authors.lastname: Dasgupta
authors.forename: U
authors.initials: U
authors.lastname: Sen
authors.forename: S
authors.initials: S
authors.lastname: Biswas
authors.forename: C
authors.initials: C
authors.lastname: Chakrabarti
authors.forename: J K
authors.initials: JK
authors.lastname: Dattagupta
mesh_terms: D000818:Animals; D001059:Apoproteins / Q000302:isolation & purification / Q000648:ultrastructure; D002645:Chickens; D018360:Crystallography, X-Ray; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D014168:Transferrin / Q000302:isolation & purification* / Q000648:ultrastructure*
chemical_list: D001059:Apoproteins; D014168:Transferrin