Crystal structure of a human embryonic haemoglobin: The carbonmonoxy form of Gower II (α2ε2) haemoglobin at 2.9 Å resolution

Abstract

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 α2ε2 (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 Å to give a final model with R-factor = 0.185 and R(free) = 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 α subunit is e..