| Project/Area Number |
01480542
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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 |
生物物性学
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| Research Institution | Osaka University |
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Principal Investigator |
TOKUNAGA Fumio Osaka University, Faculty of Science, Department of Biology Professor, 理学部, 教授 (80025452)
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| Co-Investigator(Kenkyū-buntansha) |
尾崎 浩一 大阪大学, 理学部, 助手 (90194539)
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| Project Period (FY) |
1989 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1991: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1990: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1989: ¥4,100,000 (Direct Cost: ¥4,100,000)
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| Keywords | Retinal Proteins / Bacteriorhodopsin / Retinol Binding Protein / Chromophore / Model Proteins / Visual Pigments / 視物質 / レチノ-ル結合蛋白質 / レチナ-ルタンパク質 / プロトンポンプ / 視覚 / モデルタンパク質 |
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| Research Abstract |
Retinal proteins commonly have retianl as the chromophore but are different in the protein part so they have differnt color and function from each other. In this study we compared the colors and the functions among bactriorhodopisn, visual pigments, retinol-binding protein and retinochrome. We constructed artificial bacteriorhodopsins with partial peptides and compared the charactors with natural one. We could prepared an artificial bacteriorhodopsin wth chemically synthesized peptides corresponding to helices A and B and a peptide corresponding to helices C-G which was prepared from natural bacteriorhodopsin. The articial bacteriorhodopsin consisted of two species : One has the same color as the native one and the other has lambda_<max> around 480 nm. They were in a thermal equilibrium. Each pigment has own photocycle. These results suggest that amino acid residues in helices A andB play rolls for controlling color of bacteriorhodopsin. For promoting this series of experiments, we set
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up the expression system of partial peptides of bacteriorhodopsin in E. coli by recombinant DNA techniques and have already obtained some peptide fragments. By x-ray diffraction experiments we proved that helices B and G moved on functioning. We compared the amino acid sequences and the colors of visual pigments among various animals. The results strongly suggests that visual pigment genes of vertebrates have fundamentally evolved along five lines and that the amino acid residues which are conserved in visual pigments belonging to each line play some rolls for the expression of the colo. We performed experiments of retinal binding with beta lactogloblin which has the similar beta barrel structure to retinol-binding protein, but we could not detect the obvious evidences showing the b ing. Next we tried to bind retinal Schiff base and the protonated Schiff base which were made with retinal and butylamine, but the binding constants were small, so we have to improve the experiment systems. It was found that retinochorme has a protonated Schiff base as the same as other retinal proteins proteins and that carboxyl groups are deprotonated on functioning. Less
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