Crystal structure of oxygenated Scapharca dimeric hemoglobin at 1.7-A resolution

UMMS Affiliation

Program in Molecular Medicine; Department of Biochemistry and Molecular Pharmacology

Publication Date


Document Type



Animals; Binding Sites; Bivalvia; Computer Simulation; Crystallography, X-Ray; Heme; Hemoglobins; Ligands; Models, Molecular; Oxyhemoglobins; Protein Conformation; Water


Life Sciences | Medicine and Health Sciences


The crystal structure of the cooperative dimeric hemoglobin from the blood clam Scapharca inaequivalvis has been determined in the oxygenated state and refined to an R-factor of 0.157 at 1.7-A resolution. The structure is very similar to the carbon monoxide-liganded form with subtle differences in ligand binding geometry. Oxygen binds to the heme iron in a bent conformation with Fe-O-O angles of 135 degrees and 150 degrees for the two subunits. These observed angles are lower than the equivalent angles in the carbon monoxide-liganded form and intermediate between the angles observed in structures of oxygenated sperm whale myoglobin and oxygenated human hemoglobin. This third high resolution structure of Scapharca dimeric hemoglobin permits a detailed analysis of the water structure in the highly hydrated interface between subunits.


J Biol Chem. 1994 Oct 14;269(41):25259-67.

Journal/Book/Conference Title

The Journal of biological chemistry

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Link to Article in PubMed

PubMed ID