Dynamical structural distributions in proteins

A moment analysis of the self-intermediate scattering function is used to reconstruct the distribution of structural displacements in the small protein myoglobin as a function of time, temperature and environment. Model-independent information is obtained on mean squared displacements and the Gauss-deviation. Two types of molecular motions were identified: rotational jumps of side chains and small-scale translational displacements induced by interfacial water. The displacements of water on the protein surface increase sublinearly with time and the fourth moment deviates from a Gaussian value.