2OIF

The crystal structure of ferric cyanide bound barley hexacoordinate hemoglobin.

Summary for 2OIF

• Entry DOI: 10.2210/pdb2oif/pdb
• Descriptor: Non-legume hemoglobin, CYANIDE ION, PROTOPORPHYRIN IX CONTAINING FE, ... (5 entities in total)
• Functional Keywords: hexacoordinate hemoglobin, barley, ligand binding, non-symbiotic, symbiotic, evolution, conformational changes, oxygen transport, metal binding protein
• Biological source: Hordeum vulgare
• Total number of polymer chains: 8
• Total formula weight: 150673.41

Authors

Hoy, J.A. (deposition date: 2007-01-10, release date: 2007-07-24, Last modification date: 2023-12-27)

Primary citation

Hoy, J.A.,Robinson, H.,Trent III, J.T.,Kakar, S.,Smagghe, B.J.,Hargrove, M.S.
Plant hemoglobins: a molecular fossil record for the evolution of oxygen transport
J.Mol.Biol., 371:168-179, 2007

PubMed Abstract: The evolution of oxygen transport hemoglobins occurred on at least two independent occasions. The earliest event led to myoglobin and red blood cell hemoglobin in animals. In plants, oxygen transport "leghemoglobins" evolved much more recently. In both events, pentacoordinate heme sites capable of inert oxygen transfer evolved from hexacoordinate hemoglobins that have unrelated functions. High sequence homology between hexacoordinate and pentacoordinate hemoglobins in plants has poised them for potential structural analysis leading to a molecular understanding of this important evolutionary event. However, the lack of a plant hexacoordinate hemoglobin structure in the exogenously ligand-bound form has prevented such comparison. Here we report the crystal structure of the cyanide-bound hexacoordinate hemoglobin from barley. This presents the first opportunity to examine conformational changes in plant hexacoordinate hemoglobins upon exogenous ligand binding, and reveals structural mechanisms for stabilizing the high-energy pentacoordinate heme conformation critical to the evolution of reversible oxygen binding hemoglobins.

PubMed: 17560601
DOI: 10.1016/j.jmb.2007.05.029

Experimental method

X-RAY DIFFRACTION (1.8 Å)