| Project/Area Number |
15GS0320
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| Research Category |
Grant-in-Aid for Creative Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Institution | Osaka University |
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Principal Investigator |
HASE Toshiharu Osaka University, Institute for Protein Research, Professor (00127276)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAO Toshifumi Osaka University, Professor (10197048)
KURISU Genji The University of Tokyo, Graduate School of Arts and Sciences, Associate Professor (90294131)
OOSAWA Kenji Gunma University, Graduate School of Engineering, Professor (50203758)
IKEGAMI Takahisa Osaka University, Associate Professor (20283939)
月原 冨武 大阪大学, たんぱく質研究所, 教授 (00032277)
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| Project Period (FY) |
2003 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥327,860,000 (Direct Cost: ¥252,200,000、Indirect Cost: ¥75,660,000)
Fiscal Year 2007: ¥67,600,000 (Direct Cost: ¥52,000,000、Indirect Cost: ¥15,600,000)
Fiscal Year 2006: ¥66,300,000 (Direct Cost: ¥51,000,000、Indirect Cost: ¥15,300,000)
Fiscal Year 2005: ¥99,970,000 (Direct Cost: ¥76,900,000、Indirect Cost: ¥23,070,000)
Fiscal Year 2004: ¥93,990,000 (Direct Cost: ¥72,300,000、Indirect Cost: ¥21,690,000)
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| Keywords | Plant / Protein / Structural biology / Photosynthesis / Proteome / X線結晶解析 / マススペクトロメトリー / 電子伝達複合体 / NMR / フェレドキシン / フェレドキシン:NADP還元酵素 / シロイヌナズナ / X線結晶構造 / 電子伝達 |
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| Research Abstract |
Plants synthesize various biomaterials through the reductive assimilation of inorganic carbon and nitrogen compounds. In these metabolic processes, an electron carrier protein, ferredoxin (Fd) plays a main role as an electron donor in the networks of energy and metabolic pathways. This study focused structures and functions of molecular machineries in these networks. Three projects were planed; 1) elucidation-of redox cascades via Fd in chloroplasts and nonphotosynthetic plastids, 2) determination of the structures of electron transfer complexes between Fd and partner enzymes, and 3) study of regulatory basis of these network in light of the electron partitioning.
Following results have been obtained. 1) Structures of leaf-type Fd, FNR and their complex, root-type Fd, FNR and their complex, SiR, and complex of Fd and SiR were determined by x-ray crystallographic analysis. In these 3 complexes, different molecular surface of Fd were contributed as the area for the interaction of each partner enzyme. The distances between redox centers in the complexes are different, but a through-space electron transfer seems to operate in both cases. 2) Protein-protein interaction in the complexes of Fd: FNR and Fd: SiR were elucidated by NMR analysis and the molecular recognition in solution state agrees well with that in crystal. 3) Knock-out mutant of FNR and knock-down mutant of Fd in Arabidopsis were selected. The resulting mutants, in which amounts of FNR and Fd and sub-chloroplast distribution of FNR were changed, showed an alteration in the electron partitioning between carbon and nitrogen assimilation, decrease in non-cyclic electron transfer level, and increase in reducing state level of photosystem II. These phenomena indicated the absolute amount of Fd and FNR, and their ratio are crucial factors for determination of electron availability and partitioning in chloroplasts.
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