Investigation of ultrafast structural dynamics of proteins using time-resolved X-ray solution scattering

Abstract

The molecular structures of various reaction intermediates generated during a chemical reaction play an important role in determining the reaction pathway and resulting products of a chemical reaction. For the past 20 years, the time-resolved X-ray solution scattering (TRXSS) has served as a key experimental method to visualize the structures of reaction intermediates generated during chemical reactions. With the emergence of X-ray free electron lasers (XFELs), the structural dynamics even within 100 ps became accessible using femtosecond-TRXSS (fs-TRXSS) with the aid of the X-ray pulse generated by XFELs. However, there has been a limited number of examples of ultrafast structural dynamics studies on proteins using TRXSS. Here, I present the ultrafast structural dynamics of the proteins revealed by fs-TRXSS. Via fs-TRXSS, a distinct reaction intermediate, which was not observed in the previous studies due to the insufficient time resolution, was identified. In addition, unique ultrafast structural dynamics of a protein, such as the coherent motion, and the change of the hydration shell surrounding the protein were successfully captured.