1998 Fiscal Year Final Research Report Summary
Studies of structural fluctuations of complex systems by transient hole-burning
| Project/Area Number |
09440118
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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 |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | Nara Institute of Science and Technology (1998)
Osaka University (1997) |
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Principal Investigator |
KUSHIDA Takashi Nara Institute of Science and Technology, Graduate School of Materials Science, Professor, 物質創成科学研究科, 教授 (00013516)
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| Co-Investigator(Kenkyū-buntansha) |
KANEMATSU Yasuo Osaka University, Graduate School of Science, Research Associate, 大学院・理学研究科, 助手 (00211855)
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| Project Period (FY) |
1997 – 1998
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| Keywords | conformational dynamics / hole-burning / complex systems / myoglobin / glass transition |
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| Research Abstract |
The time-resolved spectral hole-burning spectroscopy we have developed is an excellent method that enables us directly to observe the equilibrium conformational fluctuations in various materials over wide temperature and time ranges. We have improved the temporal resolution of this method to 10 ns, and applied it to merbromin dye and zinc-substituted myoglobin in a water-glycerol mixture. It has been found that the time dependence of the barycenter of the hole is expressed by a stretched exponential function and that the correlation time of the fluctuation obeys the Vogel-Fulcher law over the 150-300 K temperature range. The time behavior is much more non-exponential and much weakly dependent on temperature in protein solutions compared with dye solutions. It has been directly demonstrated that the conformational dynamics of a protein molecule is strongly dependent on that of its surroundings, and the glass transition of the protein is governed by the freezing of the solvent. Whole the obtained results have been found to be explained well by a hierarchically constrained dynamics model. We have also compared the conformational dynamics between native-like and moltenglobule-like cytochrome c. Further, it has been shown that the spectral shapes of the Qx and Qy bands of myoglobin and cytochrome c, which are buried in the inhomogeneously broadened absorption bands, can be determined using polarization spectroscopy in addition to the time-resolved spectral hole-burning.
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