| Project/Area Number |
09460036
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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 |
Plant nutrition/Soil science
|
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
MAE Tadahiko Tohoku University, 大学院・農学研究科, 教授 (60134029)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIDA Hiroyuki Tohoku University, 大学院・農学研究科, 助手 (60312625)
MAKINO Amane Tohoku University, 大学院・農学研究科, 助教授 (70181617)
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| Project Period (FY) |
1997 – 1999
|
| Project Status |
Completed (Fiscal Year 1999)
|
| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1997: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | Rubisco / reactive oxygen species / light stress / oxidative stress / degradation / photosynthesis / 葉緑体 / 植物 / 酸素ストレス |
|---|
| Research Abstract |
Rubilose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39, Rubiscso) is a bifunctional enzyme which catalyzes two competing reactions, photosynthetic COィイD22ィエD2 assimilation and photorespiratory carbon oxidation in the stroma of the chloroplasts, and is the most abundant protein in leaves. During leaf senescence or under environmental stress conditions, Rubisco is one of the early proteins that are broken down in leaves. However, only limited information is available on the triggering mechanisms that cause Rubisco degradation in plants. Here, we found that the large subunit of Rubisco is directly, fragmented into the 37-kDa and 16-kDa fragments by reactive oxygen species generated in the illuminated lysates of chloroplasts or intact chloroplasts. Analysis of the terminal amino acid residues of both fragments indicated that the fragmentation of the LSU occurs at Gly-329. Purified Rubisco, exposed to a hydroxyl radical generating system, was also cleaved at the same site. Reactive oxygen species generated at its catalytic site by a Fenton-type reaction may trigger the site specific degradation of the LSU in the light.
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