1a9w

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HUMAN EMBRYONIC GOWER II CARBONMONOXY HEMOGLOBIN

Contents 1 Overview 2 Disease 3 About this Structure 4 Reference

Overview

The production of recombinant embryonic haemoglobins via a yeast, expression system has enabled structural and functional studies to be, conducted on these proteins. As part of a programme aimed at understanding, the properties of the embryonic haemoglobins we have crystallized the, human alpha2 epsilon2 (Gower II) embryonic haemoglobin in its carbonmonoxy, form, and determined its structure by X-ray crystallography. The structure, was solved by molecular replacement and refined at 2.9 A to give a final, model with R-factor=0.185 and Rfree=0.235. The Gower II hemoglobin, tetramer is intermediate between the adult R and R2 states, though closer, to R2. The tertiary structure of the conserved alpha subunit is, essentially identical when compared to that found in the adult (alpha2, beta2) and fetal (alpha2 gamma2) hemoglobins. The embryonic epsilon, subunit has a structure very similar to that of the homologous adult beta, and fetal gamma subunits, although with small differences at the N, terminus and in the A helix. Amino acid substitutions can be identified, that may play a role in the altered response of the Gower II haemoglobin, to allosteric effectors, in particular chloride ions. The reduced chloride, effect is thought to be the primary cause of the higher affinity of this, embryonic hemoglobin in comparison to the adult molecule.

Disease

Known diseases associated with this structure: Diphtheria, susceptibility to OMIM:[126150], Erythremias, alpha- OMIM:[141800], Erythrocytosis OMIM:[141850], Heinz body anemia OMIM:[141850], Heinz body anemias, alpha- OMIM:[141800], Hemoglobin H disease OMIM:[141850], Hypochromic microcytic anemia OMIM:[141850], Methemoglobinemias, alpha- OMIM:[141800], Thalassemia, alpha- OMIM:[141850], Thalassemias, alpha- OMIM:[141800]

About this Structure

1A9W is a Protein complex structure of sequences from Homo sapiens with HEM and CMO as ligands. Full crystallographic information is available from OCA.

Reference

Crystal structure of a human embryonic haemoglobin: the carbonmonoxy form of gower II (alpha2 epsilon2) haemoglobin at 2.9 A resolution., Sutherland-Smith AJ, Baker HM, Hofmann OM, Brittain T, Baker EN, J Mol Biol. 1998 Jul 17;280(3):475-84. PMID:9665850

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