1990 Fiscal Year Final Research Report Summary
Assembly of Photosynthetic Electron Transport Systems
| Project/Area Number |
01540569
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | Meijo University |
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Principal Investigator |
TAKABE Teruhiro Faculty of Science & Technology, Professor, 理工学部, 教授 (80097766)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Hirofumi Faculty of Science & Technology, Lecturer, 理工学部, 講師 (00193607)
IWASAKI Yukimoto Faculty of Science & Technology, Lecturer, 理工学部, 講師 (20193732)
ISHIKAWA Hiroshi Faculty of Science & Technology, Associate Professor, 理工学部, 助教授
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| Project Period (FY) |
1989 – 1990
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| Keywords | Light-Energy / Gene Expression / Photosynthesis / Electron Transfer / Crop |
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| Research Abstract |
1. Structure and expression of genes the which encode P700-chlorophyll a protein complex---
(1) A cDNA clone encoding the polypeptide from cucumber PSI (P700-chlorophyll a protein) complex that migrates with apparent molecular weight of 20 kDa on SDS-polyacrylamide gels has been isolated. The 907-bp sequence of this clone has been determined and contains one open reading frame that encodes a 22, 720-Da precursor polypeptide. The molecular weight of the mature polypeptide was predicted to be 17, 037-Da. The polypeptide was identified as the PsaD gene product. The biogenesis of this polypeptide was also studied. These results were published as a paper : Plant Cell Physiol. 31, 871-879, 1990.
(2) Structural and functional aspects of cucumber PSI complexes have been studied. The PSI complex which contains eight polypeptides with apparent molecular masses of 65/63, 20, 19.5, 18.5, 17.5, 7.6, and 5.8 kDa, has been shown to catalyze the light-dependent transfer of electrons from plastocyanin to
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ferredoxin. It was found that the amount of 18.5 kDa-polypeptide is sensitive for the activity. The 18.5 kDa-polypeptide was identified as PsaF gene product and plastocyanin docking protein. A paper describing these results was submitted.
(3) The N-terminal amino acid sequencing was carried out to characterize the genes of cucumber PSI complex that catalyzes the light-dependent transfer of electrons from plastocyanin to ferredoxin. A paper describing these results is in the press.
2. Assembly of pigments-protein complexes during greening---
The relationship between the accumulation of chlorophyll, heme and polypeptides during greening of cucumber cotyledons was studied. It was found that distribution of newly synthesized chlorophyll among apo-proteins is regulated by the relative rates of synthesis of chlorophyll a and apo-proteins as well as the differential affinities of the apo-proteins for chlorophyll a but not chlorophyll b. These results were published as a paper : Plant Cell Physiol. 31, 639-647, 1990.
3. Expression of precursor plastocyanin in E. coli and reconstitution of mature plastocyanin---
The precursor plastocyanin was expressed in E. coli and partially purified. The precursor plastocyanin was processed in vitro into the mature apo-plastocyanin. Copper atom was incorporated into the apo-protein the and resulting holo-protein exhibited the same activity for the electron transfer with the native purified plastocyanin. A paper describing these results is in the press. Less
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