Water plays a major role in biosystems, greatly contributing to determine their structure, stability, and function. It is well known, for instance, that proteins require a minimum amount of water to be fully functional. Despite many years of intensive research, however, the detailed nature of protein–hydration water interactions is still partly unknown. The widely accepted “protein dynamical transition” scenario is based on perfect coupling between the dynamics of proteins and that of their hydration water, which has never been probed in depth experimentally. I present here high-resolution elastic neutron scattering measurements of the atomistic dynamics of lysozyme in water. The results show for the first time that the dynamics of proteins and of their hydration water are actually decoupled at low temperatures. This important result challenges the “protein dynamical transition” scenario and requires a new model to link protein dynamics to the dynamics of its hydration water.

中文翻译：

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中子散射法测定的水和蛋白质动力学的低温解耦

水在生物系统中起着重要作用，极大地决定了它们的结构，稳定性和功能。例如，众所周知，蛋白质需要最少的水才能充分发挥功能。尽管进行了多年的深入研究，但是蛋白质-水合水相互作用的详细性质仍然部分未知。广泛接受的“蛋白质动力学转变”场景是基于蛋白质动力学与其水合水动力学之间的完美耦合，这从未在实验中进行过深入探讨。我在这里介绍了水中溶菌酶的原子动力学的高分辨率弹性中子散射测量。结果首次表明，蛋白质及其水合水的动力学在低温下实际上是分离的。