Meinhold Lars, Clement David, Tehei Moeava, Daniel Roy, Finney John L, Smith Jeremy C
Heidelberg University, Interdisciplinary Center for Scientific Computing, Computational Molecular Biophysics, Heidelberg, Germany.
Biophys J. 2008 Jun;94(12):4812-8. doi: 10.1529/biophysj.107.121418. Epub 2008 Feb 29.
The temperature dependence of the dynamics of mesophilic and thermophilic dihydrofolate reductase is examined using elastic incoherent neutron scattering. It is demonstrated that the distribution of atomic displacement amplitudes can be derived from the elastic scattering data by assuming a (Weibull) functional form that resembles distributions seen in molecular dynamics simulations. The thermophilic enzyme has a significantly broader distribution than its mesophilic counterpart. Furthermore, although the rate of increase with temperature of the atomic mean-square displacements extracted from the dynamic structure factor is found to be comparable for both enzymes, the amplitudes are found to be slightly larger for the thermophilic enzyme. Therefore, these results imply that the thermophilic enzyme is the more flexible of the two.
利用弹性非相干中子散射研究了嗜温与嗜热二氢叶酸还原酶动力学的温度依赖性。结果表明，通过假设一种类似于分子动力学模拟中所见分布的（威布尔）函数形式，可以从弹性散射数据中得出原子位移振幅的分布。嗜热酶的分布比嗜温酶的分布明显更宽。此外，虽然从动态结构因子中提取的原子均方位移随温度的增加速率在两种酶中相当，但发现嗜热酶的振幅略大。因此，这些结果表明嗜热酶在两者中更具柔韧性。
