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-thalassernia, major, where there is a failure of beta-chain production, HbA(2) acts as the predominant oxygen deliverer. 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 Ebeta-thalassemia. X-ray diffraction data of HbA(2) and HbE were collected up to 2.1 and 1.73 Angstrom, respectively. HbA(2) crystallized in space group P2(1) with unit cell parameters a = 54.33 Angstrom, b = 83.73 Angstrom, c = 62.87 Angstrom, and beta = 99.80degrees whereas HbE crystallized in space group P2(1)2(1)2(1) with unit cell parameters a = 60.89 Angstrom, b = 95.81 Angstrom, and c = 99.08 Angstrom. Asymmetric unit in each case contains one Hb tetramer in R-2 state. (C) 2003 Elsevier Science (USA). All rights reserved.