Observation of Hydration State by Terahertz Spectroscopy and the Role of Hydration Water in Protein Stabilization

Abstract

Importance of water in stabilizing the folded structure of proteins has long been well known thermodynamically. However, the understanding of the hydration water in protein stabilization at the microscopic molecular level has been insufficient. We have investigated the mobility of water around proteins by terahertz spectroscopy, comparing it with the thermodynamics and hydrogen bonding structure, and have revealed that “weakly affected water” by the protein is deeply involved in the stabilization of the folded structure. We have also shown that small organic molecules (osmolytes) indirectly contribute to protein stabilization/destabilization by changing the state of water.