| Project/Area Number |
10206206
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas (B)
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| Allocation Type | Single-year Grants |
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| Research Institution | Kyoto University
Nagoya Institute of Technology |
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Principal Investigator |
KANDORI Hideki Nagoya Institute of Technology, Applied Chemistry, Associate Professor, 工学部, 助教授 (70202033)
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| Co-Investigator(Kenkyū-buntansha) |
SHICHIDA Yoshinori Kyoto University, Biophysics, Professor, 大学院・理学研究科, 教授 (60127090)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥24,800,000 (Direct Cost: ¥24,800,000)
Fiscal Year 2000: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1999: ¥10,500,000 (Direct Cost: ¥10,500,000)
Fiscal Year 1998: ¥10,900,000 (Direct Cost: ¥10,900,000)
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| Keywords | infrared spectroscopy / retinal / proton pump / isomerization / ultrafast spectroscopy / bacteriorhodopsin / visual rhodopsin / dynamics / 超高速分光 |
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| Research Abstract |
We have investigated the mechanism of biomolecular chemical reactions. In particular, our main target was cis-trans isomerization and proton transfer reactions in rhodopsins, such as light-driven proton pump bacteriorhodopsin and visual rhodopsin. In rhodopsins, specific reactions in protein environments convert light into protein structural changes, whose relaxation leads to the functional processes. In this project, we approached such specificity from both dynamical and structural aspects. Following results were obtained.
As the dynamical aspects, we were able to capture the excited-state dynamics of visual rhodopsin and pharaonis phoborhodopsin, acting as light sensors in our vision and bacterial phototaxis, respectively, by means of femtosecond fluorescence spectroscopy. It was revealed that the protein environment facilitates efficient cis-trans photoisomerization of the retinal chromophore.
As the structural aspects, we monitored protein structural changes through inter-atomic vibrations by (Fourier-transform) infrared spectroscopy. In particular, highly optimized experimental set-up allowed to detect the spectral changes in the X-H and X-D stretching frequency regions for the first time. Direct information on the hydrogen-bonding alterations was obtained. The results involved were for bacteriorhodopsin, color visual pigments for green and red lights, and pharaonis phoborhodopsin. These results provide new structural information on the reaction specificity ; on how protein respond to light, and functional processes are driven.
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