Transient grating spectroscopy to reveal the molecular mechanism of protein reactions

Abstract

In addition to the static structures of proteins, information on dynamic structural changes in the time-domain is essential to understand the molecular mechanism of biological functions of proteins. Recently, we have developed novel methods based on transient grating (TG) spectroscopy to measure the time-dependent diffusion coefficient and thermodynamical properties, both of which are closely related to conformation change. In this article, the principle of the TG method for revealing the protein reaction is described. As an example, our recent study of the light-induced DNA binding reaction of the photo-sensor protein EL222 is presented. The dynamics of light-induced protein dimerization and DNA binding were determined by time-dependent diffusion detection. The reaction scheme and a mechanism for a specific DNA binding process were proposed based on the results.