Abstract
During biological function of proteins in cells, the structural of the proteins change dramatically. In order to understand the principle and the molecular mechanism of the protein reactions, it is essential to elucidate the reaction dynamics in time-domain. Although static protein structures obtained from such as the X-ray crystallographic data are very important, they cannot provide us idea on the reaction dynamics and it is difficult to tell whether or not the protein structures in the crystalline forms are really important in physiological conditions (e.g. in solution phase at room temperature). At the same time, the protein structure is very soft and its structural fluctuation is also very important for the efficient and selective reactions. However, traditional spectroscopies do not possess a capability for these studies. Recently we have developed novel methods to study the conformation, energy, and intermolecular interaction dynamics from a view point of time-resolved thermodynamical properties and transport properties. Here I will briefly summarize the principle and the methods for the measurements, and then discuss biological protein reactions by taking examples of sensory Rhodopsin, which is a photo-sensor of a bacteria, and other protein reactions.
