1997 Fiscal Year Final Research Report Summary
Degration and removal of the proteins in photosystem II during photoinhibition
| Project/Area Number |
08836007
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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 |
光生物学
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
YAMAMOTO Yasusi OKAYAMA UNIVERSITY,Faculty of Science, Professor, 理学部, 教授 (40091251)
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| Project Period (FY) |
1996 – 1997
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| Keywords | photosynthesis / photosystem II / photoinhibition / DI protein / turn-over / plant physiology / active oxygen / rodical |
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| Research Abstract |
When plants are illuminated with strong light, photoinhibition of photosynthesis takes place. The target of photoinhibition is photosystem II.In the present study, damage, degradation and recovery processes of the reaction-center binding D1 protein in photosystem II during light stress were studied with spinach PS II membranes, PS II core samples and Chlamydomonas cells. The results obtained are as follows ;
(1) An extrinsic 33 kDa protein of photosystem II regulates the damage-degradation step of the D1 protein. The 33-kDa protein decreases the aggregation of D1 and at the same time enhances the degradation of D1.
(2) Active oxygen molecules are involved in the degradation of D1 not only in the reducing-side photoinhibition, but also in the donor-side photoinhibition.
(3) A large conformational change cn be detected by FTIR under the illumination of the PS II samples with strong light, but no siggnificant structural changes in PS II was found in hydrogen peroxide treatment of the PS II samples.
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