Cornell High Energy Synchrotron Source, Laboratory of Atomic and Solid State Physics, and Department of Physics, Cornell University, Ithaca, NY 14853, USA.
Proc Natl Acad Sci U S A. 2011 Dec 27;108(52):20897-901. doi: 10.1073/pnas.1110840108. Epub 2011 Dec 13.
Proteins are known to undergo a dynamical transition at around 200 K but the underlying mechanism, physical origin, and relationship to water are controversial. Here we report an observation of a protein dynamical transition as low as 110 K. This unexpected protein dynamical transition precisely correlated with the cryogenic phase transition of water from a high-density amorphous to a low-density amorphous state. The results suggest that the cryogenic protein dynamical transition might be directly related to the two liquid forms of water proposed at cryogenic temperatures.
众所周知，蛋白质在 200K 左右会经历一个动力学转变，但这种转变的潜在机制、物理起源以及与水的关系仍存在争议。在这里，我们报告了在低至 110K 温度下观察到的蛋白质动力学转变。这种出人意料的蛋白质动力学转变与水的低温相转变精确相关，水从高密度无定形态向低密度无定形态转变。研究结果表明，低温下提出的两种液态水形式可能与低温蛋白质动力学转变直接相关。
