Liquid-like side-chain dynamics in myoglobin.

At temperatures above approximately 200 K the motions of atoms in globular proteins contain a non-vibrational component that gives rise to characteristic elastic and quasi-elastic neutron scattering profiles. There is evidence that the non-vibrational dynamics is required for protein function. Here we show by analysing a molecular dynamics simulation of myoglobin that the neutron scattering results from liquid-like rigid-body motion of the protein side-chains.