Tsai A M, Neumann D A, Bell L N
Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Biophys J. 2000 Nov;79(5):2728-32. doi: 10.1016/S0006-3495(00)76511-8.
Glycerol has been shown to lower the heat denaturation temperature (T(m)) of dehydrated lysozyme while elevating the T(m) of hydrated lysozyme (. J. Pharm. Sci. 84:707-712). Here, we report an in situ elastic neutron scattering study of the effect of glycerol and hydration on the internal dynamics of lysozyme powder. Anharmonic motions associated with structural relaxation processes were not detected for dehydrated lysozyme in the temperature range of 40 to 450K. Dehydrated lysozyme was found to have the highest T(m) by. Upon the addition of glycerol or water, anharmonicity was recovered above a dynamic transition temperature (T(d)), which may contribute to the reduction of T(m) values for dehydrated lysozyme in the presence of glycerol. The greatest degree of anharmonicity, as well as the lowest T(d), was observed for lysozyme solvated with water. Hydrated lysozyme was also found to have the lowest T(m) by. In the regime above T(d), larger amounts of glycerol lead to a higher rate of change in anharmonic motions as a function of temperature, rendering the material more heat labile. Below T(d), where harmonic motions dominate, the addition of glycerol resulted in a lower amplitude of motions, correlating with a stabilizing effect of glycerol on the protein.
甘油已被证明可降低脱水溶菌酶的热变性温度（T(m)），同时提高水合溶菌酶的T(m)（《药物科学杂志》84:707 - 712）。在此，我们报告一项关于甘油和水合作用对溶菌酶粉末内部动力学影响的原位弹性中子散射研究。在40至450K温度范围内，未检测到与脱水溶菌酶结构弛豫过程相关的非谐运动。发现脱水溶菌酶具有最高的T(m)。加入甘油或水后，在动态转变温度（T(d)）以上恢复了非谐性，这可能有助于解释在甘油存在下脱水溶菌酶T(m)值的降低。用水溶剂化的溶菌酶观察到最大程度的非谐性以及最低的T(d)。还发现水合溶菌酶具有最低的T(m)。在T(d)以上的区域，大量甘油导致非谐运动随温度变化的速率更高，使材料更易受热破坏。在T(d)以下，谐性运动占主导，加入甘油导致运动幅度降低，这与甘油对蛋白质的稳定作用相关。
