1nqp

From Proteopedia

Revision as of 16:17, 12 November 2007

Crystal structure of Human hemoglobin E at 1.73 A resolution

Overview

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.

Disease

Known diseases associated with this structure: Erythremias, alpha- OMIM:[141800], Erythremias, beta- OMIM:[141900], Erythrocytosis OMIM:[141850], HPFH, deletion type OMIM:[141900], Heinz body anemia OMIM:[141850], Heinz body anemias, alpha- OMIM:[141800], Heinz body anemias, beta- OMIM:[141900], Hemoglobin H disease OMIM:[141850], Hypochromic microcytic anemia OMIM:[141850], Methemoglobinemias, alpha- OMIM:[141800], Methemoglobinemias, beta- OMIM:[141900], Sickle cell anemia OMIM:[141900], Thalassemia, alpha- OMIM:[141850], Thalassemia-beta, dominant inclusion-body OMIM:[141900], Thalassemias, alpha- OMIM:[141800], Thalassemias, beta- OMIM:[141900]

About this Structure

1NQP is a Protein complex structure of sequences from Homo sapiens with CYN and HEM as ligands. Full crystallographic information is available from OCA.

Reference

Crystallization and preliminary X-ray structural studies of hemoglobin A2 and hemoglobin E, isolated from the blood samples of beta-thalassemic patients., Dasgupta J, Sen U, Choudhury D, Datta P, Chakrabarti A, Chakrabarty SB, Chakrabarty A, Dattagupta JK, Biochem Biophys Res Commun. 2003 Apr 4;303(2):619-23. PMID:12659864

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