Real-time observation of conformational fluctuations in Zn-substituted myoglobin by time-resolved transient hole-burning spectroscopy.
Equilibrium fluctuations of the protein conformation have been studied in myoglobin by a novel method of time-resolved transient hole-burning spectroscopy over a temperature range of 180-300 K and a time range of 10 ns to 10 ms. The temporal shift of the hole spectrum has been observed in a wide temperature region of 200-300 K. It has been found that the time behavior of the peak position of the hole is highly nonexponential and can be expressed by a stretched exponential function with a beta value of 0.22. As compared with the results for a dye solution sample, the time scale of the fluctuation of the protein conformation is much more weakly dependent on temperature. The time scale of the observed conformational dynamics shows a temperature dependence similar to that associated with the ligand escape process of myoglobin.
Shibata
Y
Y
Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan. yshibata@ile.osaka-u.ac.jp
Kurita
A
A
Kushida
T
T
D055592:Biophysical Phenomena; D001703:Biophysics; D004396:Coloring Agents; D066298:In Vitro Techniques; D007834:Lasers; D009211:Myoglobin / Q000737:chemistry* / Q000528:radiation effects; D011487:Protein Conformation; D012996:Solutions; D013057:Spectrum Analysis / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D015032:Zinc / Q000737:chemistry*
D004396:Coloring Agents; D009211:Myoglobin; D012996:Solutions; D015032:Zinc