Dynamics of frozen proteins as investigated by optical hole burning experiments

Abstract

We measured the spectral diffusion broadening of persistent holes burnt into the absorption band of myoglobin- and cytochrome c-type proteins as a function of waiting time. In addition we varied the ageing time. Although spectral diffusion broadening is subject to ageing, especially below 1 K, the proteins can be brought to conditions where spectral diffusion broadening is close to a stationary behavior. The time evolution of the linewidth follows a power law in time which signals that the associated motion in conformation space seems to be governed by diffusive-like processes.