Ecology of Protein Dynamics

Biological macromolecules evolved over billions of years to achieve dynamic structures adapted to their function. Appropriate structure and appropriate dynamics are necessary for biological activity. Intra and inter protein interactions are modulated by weak forces, which depend sensitively on the environment. These forces define the active fold of the macromolecule and also its dynamics about the time-average structure. Dynamics, however, is more sensitive than structure to environmental factors such as solvent, temperature or pressure. Because of inappropriate dynamics, a macromolecule can be inactive in conditions in which its correct structure is maintained and stable. It is essential, therefore, to take into account the environmental context in experimental or simulation studies of protein dynamics. Neutron scattering can provide unique experimental data to underpin molecular dynamics calculations in this context.