Multiple Channels of Structural Relaxations in Functional Proteins

The dynamics and function of proteins were shown to be coupled to motions in the bulk solvent and the hydration shell [1]. Therein, three types of protein motions were identified: (i) Those that are coupled to the dielectric fluctuations in the bulk solvent, mainly associated with the few, large-scale conformational changes such as the entrance and exit of ligands; (ii) hydration-shell coupled motions, most likely involving sidechains [2,3] and permitting processes such as the passage of ligands inside the protein; and (iii) vibrational motions that are only coupled to the internal dynamics of the protein molecule.