Kumar Pradeep, Yan Z, Xu L, Mazza M G, Buldyrev S V, Chen S-H, Sastry S, Stanley H E
Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA.
Phys Rev Lett. 2006 Oct 27;97(17):177802. doi: 10.1103/PhysRevLett.97.177802.
Using molecular dynamics simulations, we investigate the relation between the dynamic transitions of biomolecules (lysozyme and DNA) and the dynamic and thermodynamic properties of hydration water. We find that the dynamic transition of the macromolecules, sometimes called a "protein glass transition," occurs at the temperature of dynamic crossover in the diffusivity of hydration water and also coincides with the maxima of the isobaric specific heat C_{P} and the temperature derivative of the orientational order parameter. We relate these findings to the hypothesis of a liquid-liquid critical point in water. Our simulations are consistent with the possibility that the protein glass transition results from crossing the Widom line, which is defined as the locus of correlation length maxima emanating from the hypothesized second critical point of water.
通过分子动力学模拟，我们研究了生物分子（溶菌酶和DNA）的动态转变与水合水的动力学和热力学性质之间的关系。我们发现，大分子的动态转变，有时被称为“蛋白质玻璃化转变”，发生在水合水扩散率的动态交叉温度处，并且也与等压比热(C_{P})的最大值以及取向序参量的温度导数相吻合。我们将这些发现与水中液-液临界点的假设联系起来。我们的模拟结果与蛋白质玻璃化转变是由穿越维德曼线导致的这一可能性相一致，维德曼线被定义为从假设的水的第二个临界点发出的关联长度最大值的轨迹。
