Temperature dependent studies of proteins and their hydration shell properties using megahertz-to-terahertz dielectric spectroscopy

The low-frequency collective vibrational modes in proteins and the protein–water interface playing an important role in biochemical reactions and biological energy transport strongly depend on the temperature and conditions of the environment. However, capturing a precise picture of collective vibrational dynamics under temperature variations is challenging due to the strong absorption of water. For this reason, we have employed a highly sensitive dielectric megahertz-to-terahertz frequency-domain system to probe the vibrational dynamics of proteins in aqueous solutions from 50 MHz to 2 THz. With this approach, we have performed an exclusive temperature dependent study on myoglobin and lysozyme in water by means of complex dielectric analysis. We have focused on protein collective vibrational processes and atypical surrounding water molecules to outline comprehensive images of aqueous solutions. The results help us to clarify protein dynamics and protein-water interfaces in temperature dependent environment that determine biochemical functions and reactivity of proteins.