1YOI

COBALT MYOGLOBIN (OXY)

Summary for 1YOI

• Entry DOI: 10.2210/pdb1yoi/pdb
• Descriptor: MYOGLOBIN, SULFATE ION, PROTOPORPHYRIN IX CONTAINING CO, ... (5 entities in total)
• Functional Keywords: heme, oxygen transport, respiratory protein, muscle
• Biological source: Physeter catodon (sperm whale)
• Total number of polymer chains: 1
• Total formula weight: 17982.59

Authors

Brucker, E.A.,Phillips Jr., G.N. (deposition date: 1996-06-14, release date: 1996-12-07, Last modification date: 2024-02-14)

Primary citation

Brucker, E.A.,Olson, J.S.,Phillips Jr., G.N.,Dou, Y.,Ikeda-Saito, M.
High resolution crystal structures of the deoxy, oxy, and aquomet forms of cobalt myoglobin.
J.Biol.Chem., 271:25419-25422, 1996

PubMed Abstract: The structures of the deoxy, oxy, and aquomet forms of native sperm whale myoglobin reconstituted with cobalt protoporphyrin IX have been determined by x-ray crystallography. As expected, cobalt myoglobin closely resembles native iron myoglobin in overall structure, especially in their respective aquomet forms. In the cobalt oxymyoglobin structure, the Nepsilon of distal histidine 64 lies within hydrogen bonding distance to both the oxygen atom directly bonded to the cobalt and the terminal oxygen atom, in agreement with previous EPR and resonance Raman studies. The metal atom in cobaltous myoglobin does show a small 0.06-A out-of-porphyrin plane displacement when moving from the oxy to deoxy state. In the case of the native iron-containing myoglobin, the oxy to deoxy transition results in a larger 0.16-A displacement of the metal farther out of the porphyrin plane, attributed to an increase in spin from S = 0 to S = 2. The small displacement in cobalt myoglobin is due to a change in coordination geometry, not spin state (S = 1/2 for both cobalt deoxy- and oxymyoglobin). The small out-of-porphyrin plane movement of cobalt which accompanies deoxygenation of myoglobin also occurs in cobalt hemoglobin and serves to explain why cooperativity, although reduced, is still preserved when iron is replaced by cobalt in human hemoglobin.

PubMed: 8810310
DOI: 10.1074/jbc.271.41.25419

Experimental method

X-RAY DIFFRACTION (1.65 Å)