1A9W

HUMAN EMBRYONIC GOWER II CARBONMONOXY HEMOGLOBIN

Summary for 1A9W

• Entry DOI: 10.2210/pdb1a9w/pdb
• Descriptor: HEMOGLOBIN (ALPHA CHAIN), HEMOGLOBIN (BETA CHAIN), PROTOPORPHYRIN IX CONTAINING FE, ... (4 entities in total)
• Functional Keywords: oxygen transport
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 4
• Total formula weight: 65067.92

Authors

Sutherland-Smith, A.J.,Baker, H.M.,Hofmann, O.M.,Brittain, T.,Baker, E.N. (deposition date: 1998-04-11, release date: 1998-06-17, Last modification date: 2024-05-22)

Primary citation

Sutherland-Smith, A.J.,Baker, H.M.,Hofmann, O.M.,Brittain, T.,Baker, E.N.
Crystal structure of a human embryonic haemoglobin: the carbonmonoxy form of gower II (alpha2 epsilon2) haemoglobin at 2.9 A resolution.
J.Mol.Biol., 280:475-484, 1998

PubMed 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 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.

PubMed: 9665850
DOI: 10.1006/jmbi.1998.1868

Experimental method

X-RAY DIFFRACTION (2.9 Å)