2007 Fiscal Year Final Research Report Summary
Elucidation of reaction mechanism ofthe enzymes involved in the syntbssis of photosynthetic pigments
| Project/Area Number |
18570105
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural biochemistry
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| Research Institution | Osaka University |
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Principal Investigator |
FUKUYAMA Keiichi Osaka University, Graduate School of Science, Professor (80032283)
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| Project Period (FY) |
2006 – 2007
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| Keywords | bilin reductase / photosynthesis / X-ray crystallography / chlorophyll / ferredoxin / bilin pigment / γ-glutamyltranspentidase |
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| Research Abstract |
Photosynthetic organisms utilize phytobilins, linear tetrapyrrole pigments, for photosynthesis and light sensing. Such organisms develop light harvesting systems to accomplish efficient photosynthesis in their living environments. Red algae and cyanobacteria have giant protein-pigment complexes called phycobilisomes as a light-harvesting system, in which phycobilins (one of phytobilins) are utilized for light-harvesting pigments. Phytobilins are biosynthesized from heme by heme oxygenase and ferredoxin dependent bilin reductases (FDBRs). PcyA, a member of FDBR family, is unique in reducing biliverdin Xiα (BV) to phycocyanobilin by two sequential steps, in which electrons are supplied by ferredoxin. We previously determined the crystal structure of PcyA from cyanobacterium Synechocystis sp. PCC 6803 in complex with BV. To shed light on the molecular mechanism of PcyA reaction, we synthesized the pigment, the product of the first step of PcyA reduction, and determined the crystal structure of PcyA-pigment complex. On the basis of the structure site directed mutagenesis and functional analysis are under way.
γ-Glutamyltranspeptidase (GGT) catalyzes the cleavage of such γ-glutamyl compounds as glutathione, and transfer of their γ-glutamyl group to water or to other amino acids and peptides. Azaserine and acivicin are classical and irreversible inhibitors of GGT, but their binding sites and the inhibition mechanisms remained to be defined. We have determined the crystal structures of GGT from Eacherichia coil in complex with azaserine and acivicin at 1.65 A resolution. They form a covalent bond with the Oγ atom of Thr391, the catalytic residue of GGT. Notably, in the azaserine complex the carbonyl of azaserine is attacked by Thr391 to form a tetrahedral intermediate. When acivicin is bound to GGT, a migration of the single and double bonds occurs in its dihydroisoxazole ring.
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[Journal Article] Mass spectroscopic identification of lysine residues of heme oxygenase-1 that are involved in its interaction with NADPH-cytochrome P450 reductase2008
Author(s)
Y., Higashimoto, M., Sugishima, H., Sato, H., Sakamoto, K., Fukuyama, G., Palmer, M., Noguchi
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Journal Title
Biochem. Biophys. Res. Commun 367
Pages: 852-858
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Solvent Tuning of Electrochemical Potentials in the Active Sites of HiPIP Versus Ferredoxin2007
Author(s)
A., Dey, F.E., Jenney, Jr., M.W.W., Adams, E., Babini, Y., Takahashi, K., Fukuyama, K.O., Hodgson, B., Hedman, E.I., Solomon
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Journal Title
Science 318 No.5855
Pages: 1464-1468
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Crystal Structures of Escherichia coil γ-Glutamyltranspeptidase in Complex with Azaserine and Acivicin : Novel Mechanistic Implication for Inhibition by Glutamine Antagonists
Author(s)
K., Wada, J., Hiratake, M., Irie, T., Okada, C., Yamada, H., Kumagai, H., Suzuki, K., Fukuyama
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Journal Title
Description
「研究成果報告書概要(欧文)」より
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