| Project/Area Number |
60304093
|
|---|
| Research Category |
Grant-in-Aid for Co-operative Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
代謝生物化学
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
ASADA Kozi Res. Inst.Food Sci., Kyoto Univ. , Professor, 食糧科学研究所, 教授 (50027182)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SATOH Kazuhiko Faculty of Lib. Arts, Tokyo Univ., Research Associate, 教養学部, 助手 (00090522)
SATOH Kimiyuki Faculty of Science, Okayama Univ., Professor, 理学部, 教授 (10032822)
MURATA Norio Basic Biology Inst., Professor, 基礎生物学研究所, 教授 (90011569)
INOUE Yorinao Phys. Chem. Inst. (RIKEN), Chief Researcher, 主任研究員 (70087592)
ORII Yutaka Medical School, Kyoto Univ., Associate Professor, 医学部, 助教授 (60028149)
|
|---|
| Project Period (FY) |
1985 – 1986
|
| Project Status |
Completed (Fiscal Year 1986)
|
| Budget Amount *help |
¥16,000,000 (Direct Cost: ¥16,000,000)
Fiscal Year 1986: ¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 1985: ¥9,000,000 (Direct Cost: ¥9,000,000)
|
|---|
| Keywords | Chloroplasts / Water-dehydrogenase / Mn-enzyme / Photosystem <II> / Chlorophyll proteins / Thylakoid membranes / Oxygen evolution / 過酸化水素 |
|---|
| Research Abstract |
The present research project has been organized to reveal molecular properties of water-dehydrogenase in chloroplasts which donates dioxygen to aerobic organisms and is the most abundant reaction in the globes.
(1) Reaction center - PSII reaction center core complex which is composed of D1, D2 and Cyt b-559 was isolated and showed the PSII reaction, indicating that D1 and/or D2 is the reaction center. The core complex composed of D1, D2, Cyt b-559, 47-kDa and 43-kDa peptides can oxidize water after binding of the 33-kDa peptide.
(2) Peripheral peptides and Mn- Three peripheral peptides (33, 23 and 18 kDa) participating in the water oxidation have been isolated. Their topological arrangement was revealed by the immunoloical method. The 23-kDa peptide participates in the binding of Ca. The N-terminal residues of the 18-kDa are is necessary to its binding to the core. Amino acid sequence of the 33-kDa peptide was determined. The 33- kDa peptide has been shown to participate in the binding of Mn and its depletion caused the inhibition of the advancement of the s-3 to s-0 states. The target size analysis indicates that molecular size required for the binding of Mn is 65 kDa, suggesting that at least two peptides are necessary to the binding.
(3) Calcium, chloride and reaction mechanism - One atom of Ca binds to the reaction center and is essential to the reaction between P680 and Z. Chloride depletion resulted in the inhibition of the advancement of the s-1 to s-2 states. Oxygen evolution from hydrogen peroxide in PSII membranes is catalyzed by the flashinduced catalatic activity in which the S-0/s-2 cycle participates. Proton uptake step in the cytochrome c oxidase reaction has been confirmed.
|
