title: Crystallization and preliminary X-ray structural studies of hemoglobin A2 and hemoglobin E, isolated from the blood samples of beta-thalassemic patients.
abstract: Hemoglobin A(2) (alpha(2)delta(2)), a minor (2-3%) component of circulating red blood cells, acts as an anti-sickling agent and its elevated concentration in beta-thalassemia is a useful clinical diagnostic. In beta-thalassemia major, where there is a failure of beta-chain production, HbA(2) acts as the predominant oxygen delivery mechanism. Hemoglobin E, is another common abnormal hemoglobin, caused by splice site mutation in exon 1 of beta globin gene, when combines with beta-thalassemia, causes severe microcytic anemia. The purification, crystallization, and preliminary structural studies of HbA(2) and HbE are reported here. HbA(2) and HbE are purified by cation exchange column chromatography in presence of KCN from the blood samples of individuals suffering from beta-thalassemia minor and E beta-thalassemia. X-ray diffraction data of HbA(2) and HbE were collected upto 2.1 and 1.73 A, respectively. HbA(2) crystallized in space group P2(1) with unit cell parameters a=54.33 A, b=83.73 A, c=62.87 A, and beta=99.80 degrees whereas HbE crystallized in space group P2(1)2(1)2(1) with unit cell parameters a=60.89 A, b=95.81 A, and c=99.08 A. Asymmetric unit in each case contains one Hb tetramer in R(2) state.
authors.affiliation: Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064, India.
authors.forename: Jhimli
authors.initials: J
authors.lastname: Dasgupta
authors.forename: Udayaditya
authors.initials: U
authors.lastname: Sen
authors.forename: Debi
authors.initials: D
authors.lastname: Choudhury
authors.forename: Poppy
authors.initials: P
authors.lastname: Datta
authors.forename: Abhijit
authors.initials: A
authors.lastname: Chakrabarti
authors.forename: Sudipa Basu
authors.initials: SB
authors.lastname: Chakrabarty
authors.forename: Amit
authors.initials: A
authors.lastname: Chakrabarty
authors.forename: J K
authors.initials: JK
authors.lastname: Dattagupta
mesh_terms: D002850:Chromatography, Gel; D018360:Crystallography, X-Ray / Q000379:methods; D006443:Hemoglobin A2 / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D006446:Hemoglobin E / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D006801:Humans; D011487:Protein Conformation; D017086:beta-Thalassemia / Q000097:blood*
chemical_list: D006443:Hemoglobin A2; D006446:Hemoglobin E