Neutron Spin-Echo and TOF Reveals Protein Dynamics in Solution

The ps to ns dynamics of the protein alcohol dehydrogenase (ADH) has been measured in dilute solution by time-of-flight (TOF) neutron spectroscopy. The investigation extends previous experiments on ADH solutions with neutron-spin-echo spectroscopy. The interpretation of TOF experiments used the diffusion data from NSE as input to decribe the observed slow component of the quasielastic spectra, in addition a fast component to be associated to mobile groups in the protein could be observed. The description within a simple model for translational and rotational diffusion and a fraction of protons with confined local mobility is given together with a novel method to accurately and efficiently account for the instrumental resolution.