Abstract
We have studied the low-temperature properties of a hen egg white lysozyme (HEWL) crystal in cryoprotective solutions by Raman and micro-Brillouin scattering over the wide temperature range from -160℃ to 80℃. According to the observation of the characteristic Raman band of a glassy state and the continuous change of sound velocity, we have confirmed that ethylene glycol 50 mol% aqueous solution undergoes a liquid-glass transition around 150 K without crystallization even in slow cooling. We have studied a tetragonal HEWL crystal in ethylene glycol 50 mol% aqueous solution. With the decrease of temperature, the sound velocity of both solution and a crystal shows the continuous increase in all temperatures, and no abrupt jump of sound velocity due to crystallization is observed. It means that the three dimensional structure of a tetragonal HEWL crystal is preserved in low-temperatures down to -160℃.
