Time-Resolved Diffusion Method to Detect and Reveal Protein Reactions Leading to Their Functions

Abstract

Abstract Proteins are unique natural macromolecules with high selectivity and efficiency for their functions. Understanding the chemical reaction mechanisms of proteins has long been an important and attractive research subject. To study the reactions, various experimental techniques have been developed. However, the time-resolved detection of conformational changes and intermolecular interactions remains a difficult problem, although dynamics are crucial for elucidating the reaction mechanism at the molecular level. Here, time-resolved diffusion (TRD) methods developed to monitor hidden dynamics are introduced. After describing the principle, this review mainly focuses on some applications demonstrating the importance of the time-resolved detection of diffusion-sensitive conformational change (DSCC), which can reveal spectrally silent reaction processes. Correlation between DSCC and enzymatic function showed that conformation changes detected by DSCC are closely related to biological functions such as enzymatic reactions and DNA recognition. Furthermore, the TRD method can detect signal transduction processes of photosensor proteins. Hence, the time-resolved detection of DSCC is appropriate to study mechanisms of protein functions. Since this method can detect intermolecular interactions between enzymes and substrates in time-domain, one of interesting applications is a time-resolved biosensor for transient species. Advantages of the method and future perspective are discussed.