Molecular manipulation of oxygen binding proteins and new development of precise structure-function studies on them

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From the present project the following results were obtained. 1.Control of oxygen affinity of hemoglobin (Hb) with cooperativity preserved by means of artificial mutations (Imai), 2.determination of microscopic oxygen equilibrium constants and test of Mg^<2+> and Cr^<3+>-porphyrins as the model for deoxy-and oxyhemes using metal-substituted hybrid Hbs (Morimoto), 3.constitution of novel globins by module exchanges and analysis of ligand binding kinetics of myoglobin (Mb) with intramolecular disulfide bond (Morishima), 4.identification of the fifth axial ligand for the oxygen sonsor protein FixL of root nodule bacterium (Iizuka), 5.detection of structural differences at the alpha1-beta2 contacts between HbNO (+IHP) T-state and deoxyHb T-state by means of ultraviolet resonance Raman spectroscopy (Kitagawa), 6.identification of the amino acid residues contributing to the negative CD band at 287 nm as a T-state marker using mutant and chemically modified Hbs (Nagai), 7.comparison between n … More eutron diffraction data for Mb crystal and temperature-dependence data of fluctuation obtained by applying the precision normal mode analysis to X-ray diffraction data for Mb crystal (Go), 8.the role of heme group in the folding process of Mb studied by stopped-flow method using various optical probes (Kihara), 9.changes in heme-globin contacts cause only small effects on Mb functions whereas introduction of nitrogen atoms into the meso position of porphyrin causes drastic effects on Mb functions (Neya), 10.the giant size of the annelid Hb is maintained by lectin-like sugar adhesion via linker chains and determination of the location of the linker chains in the Hb molecule (Gotoh), 11.Mb from turban shell shows high homologous with indoleamine 2,3-dioxygenase, suggesting that the former evolved from the latter (Suzuki), 12.the autooxidation of Cerithidea Mb is accompanied with dimer-to-monomer conversion (Shikama) and 13.the oxygen equilibrium curve for human fetal Hb is optimized to attain highly efficient oxygen transport under low oxygen pressure environments while that for human adult Hb is optimized to utilize the Bohr effect at maximum (Kobayashi). Less