Bucciarelli Saskia, Casal-Dujat Lucía, De Michele Cristiano, Sciortino Francesco, Dhont Jan, Bergenholtz Johan, Farago Bela, Schurtenberger Peter, Stradner Anna
Physical Chemistry, Department of Chemistry, Lund University , SE-22100 Lund, Sweden.
Department of Physics, Università di Roma La Sapienza , I-00186 Roma, Italy.
J Phys Chem Lett. 2015 Nov 19;6(22):4470-4. doi: 10.1021/acs.jpclett.5b02092. Epub 2015 Oct 29.
The globular protein γB-crystallin exhibits a complex phase behavior, where liquid-liquid phase separation characterized by a critical volume fraction ϕc = 0.154 and a critical temperature Tc = 291.8 K coexists with dynamical arrest on all length scales at volume fractions around ϕ ≈ 0.3-0.35, and an arrest line that extends well into the unstable region below the spinodal. However, although the static properties such as the osmotic compressibility and the static correlation length are in quantitative agreement with predictions for binary liquid mixtures, this is not the case for the dynamics of concentration fluctuations described by the dynamic structure factor S(q,t). Using a combination of dynamic light scattering and neutron spin echo measurements, we demonstrate that the competition between critical slowing down and dynamical arrest results in a much more complex wave vector dependence of S(q,t) than previously anticipated.
球状蛋白γB-晶状体蛋白表现出复杂的相行为，其中以临界体积分数ϕc = 0.154和临界温度Tc = 291.8 K为特征的液-液相分离与在体积分数约为ϕ≈0.3 - 0.35时所有长度尺度上的动力学停滞共存，并且有一条停滞线延伸到旋节线以下的不稳定区域。然而，尽管诸如渗透压缩性和静态关联长度等静态性质与二元液体混合物的预测在定量上一致，但由动态结构因子S(q,t)描述的浓度涨落动力学并非如此。通过结合动态光散射和中子自旋回波测量，我们证明临界减慢和动力学停滞之间的竞争导致S(q,t)的波矢依赖性比先前预期的要复杂得多。
