1993 Fiscal Year Final Research Report Summary
Molecular mechanism of NAD(P)H -cyclic electron flow
| Project/Area Number |
04454014
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物生理学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
ASADA Kozi Kyoto Univ Res Inst Food Sci Professor, 食糧科学研究所, 教授 (50027182)
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| Co-Investigator(Kenkyū-buntansha) |
MANO Junichi Kyoto Univ Res Inst Food Sci Instructor, 食糧科学研究所, 助手 (50243100)
ENDO Tsuyoshi Kyoto Univ Res Inst food Sci Instructor, 食糧科学研究所, 助手 (90201962)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Cyanobacteria / Synechocystis PCC6803 / Cyclic elctron flow / NAD(P)H dehydrogenase / P700 / Chlorophyll fluorescence |
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| Research Abstract |
1. Electron donation from stromal components to P700^+ via the intersystem chain was demonstrated in spinach chloroplasts and the pool size of electrons that can be donated to P700^+ was estimated to be in the range of 12 and 28 electrons per p700 under aerobic conditions.
2. Electron flow to the intersystem chain from stromal components and cyclic elctron flow in maize were estimated by monitoring redox changes of P700 and chlorophyll fluorescence. Storomal pool size of electrons that can be donated to P700^+ was much larger in maize than in c3 plants, giving a maximum value of 225 elctrons per P700.
3. Using cyanobacteria, Synechococcus and Synechocystis, it has been demonstrated that electron donation from cyclic and respiratory flows to the photosynthetic intersystem chain is mediated by pyridine nucleotide dehydrogenase (NDH), which is analogous to mitochondrial complex I.The NDH in cyanobacteria mediates not only NADPH- dependent cyclic flow but also ferredoxin-dependent one.
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