Dynamical Transition of Collective Motions in Dry Proteins*

Water is widely assumed to be essential for protein dynamics and function. In particular, the well-documented “dynamical” transition at ~200 K, at which the protein changes from a rigid, non-functional form to a flexible, functional state, as detected in hydrogenated protein by incoherent neutron scattering, requires hydration. Here, we report on coherent neutron scattering experiments on perdeuterated proteins and reveal that a transition occurs in dry proteins at the same temperature resulting primarily from the collective heavy-atom motions. The dynamical transition discovered is intrinsic to the energy landscape of dry proteins.

Physical Review Letters 119, 048101 (2017)