| Project/Area Number |
16340121
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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 |
Biophysics/Chemical physics
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
MATSUSHITA Michio Tokyo Institute of Technology, Graduate School of Science and Technology, Associate (80260032)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥16,500,000 (Direct Cost: ¥16,500,000)
Fiscal Year 2006: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 2004: ¥8,300,000 (Direct Cost: ¥8,300,000)
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| Keywords | protein / single-molecule spectroscopy / structure-function relationship / photosynthetic antenna complex / 光合成 / アンテナ複合体 / LH12 / LH2 |
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| Research Abstract |
A protein has numerous meta-stable structures. In the physiological conditions. The structural fluctuation was pointed out for long years to be important, because the structural fluctuation plays essential role in regulating function of proteins. However, there have been no methods to elucidate the structural dynamics. To break through, we are aiming at getting structural information of single proteins by performing optical spectroscopy of individual proteins. Because measuring a fluorescence spectrum takes at least several milli-seconds, troscopic measurements are performed at temperatures low enough for the structural dynamics to be followed.
In this study we have succeeded to follow one pigment-protein complex to know the temperature dependence of structural dynamics. The experimental data, which are the very first data on the globe show clearly that substantial part of the structural movement is temperature-independent tunneling motion [Oikawa, et. al. J. Am. Chem. Soc. 130(20008)48501.].
Spectroscopy at low temperature of single proteins has been limited to the near infrared region. The method was successfully applied to photosynthetic antenna complexes of photosynthetic bacteria. Nevertheless it is worth making an effort to extend the wavelength of the setup to cover the visible region, since many enzymes absorb or emit in the visible. In order to reduce the chromatic aberration of the objective, which is immersed into liquid helium together with a sample, we have developed a reflecting objective [Fujiyoshi, et. al. Appl. Phys. Lett. 91 (2007) 051125.]. With the reflecting objective we have made two-photon excitation and measured fluorescence spectrum of single GFPs. The spectra were taken in the background-free condition, and series of spectra of the same protein revealed structural dynamics of the protein [Fujiyoshi, et. al. Phys. Rev. Lett. 100 (2008) 168101.].
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