| Project/Area Number |
10044218
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
植物生理
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| Research Institution | Waseda University |
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Principal Investigator |
SAKURAI Hidehiro Waseda University, School of Education, Professor, 教育学部, 教授 (10063645)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Kazuhito Kanagawa University, Faculty of Science, Associate Professor, 理学部, 助教授 (20221088)
KUSUMOTO Nariaki Waseda University, School of Education, Lecturer, 教育学部, 講師 (60277861)
BRETTEL Klau CEA de Saclay, DBCM, researcher
SETIF Pierre CEA de Saclay, DBCM, Research d
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥7,700,000 (Direct Cost: ¥7,700,000)
Fiscal Year 1999: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1998: ¥4,100,000 (Direct Cost: ¥4,100,000)
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| Keywords | Green Sulfur Bacteria / Heliobacteria / Reaction Center / Iron-Sulfur Cluster / Cytochrome / Quinone / Electron Transfer / Photosynthesis / 反応中心 / 閃光分光 / フェレドキシン / 電子伝達 |
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| Research Abstract |
In the reaction center complex (PS-C) from the green sulfur bacterium Chlorobium tepidum, A_0 and three Fe-S clusters function on the accepter side of the electron transfer chain and two molecules of cyt c-551 on the donor side. From multiple-flash-induced spectroscopy, we could not find any possibilities of functioning of quinone in the main electron transfer chain. On the donor side, the reduction rate of P840^+ after the first flash differed from that after the second flash, which was adequately explained by a functionally equivalent two cyt c-551 model. From the difference spectra of PS-C after the 1^<st>, 2^<nd> and the 3^<rd> flash, functioning of three Fe-S clusters was confirmed, corroborating the non-involvement of quinines on the acceptor side in the electron transfer chain, From the rereduction rates of P840^+, the rates of charge recombination between P840^+ and three Fe-S clusters and those of the leak of electron to the reaction mdeium were estimated. Analyses of the results indicate that the E_0 value of the most exposed Fe-S cluster is not the highest among the three. Four ferredoxins (Fd) were purified from C.tepidum. All of these Fd supported very high rate of NADP^+ photoreduction in the presence of PS-C from C.repidum and FNR from spinach, although their affinities differ each other.
RC (PS-H) from Heliobacillus mobilis was solubilized with a detergent, and partially purified by sucrosedensity centrifugation, and by chromatography. The PS-H preparation contained several polypeptides, showed a low Fd-reducing activity, and was sensitive to oxygen. Two Fd were purified from the bacterium. One of them had high affinity with PS-C and the other low affinity.
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