Abstract-New Insights into the Role of Water in Biological Function: Terahertz Absorption Spectroscopy and Molecular Dynamics Simulations Studies of the Solvation Dynamics of Biomolecules

Valeria Conti Nibali and Martina Havenith

J. Am. Chem. Soc., Just Accepted Manuscript

DOI: 10.1021/ja504441h

Publication Date (Web): August 15, 2014

Copyright © 2014 American Chemical Society

http://pubs.acs.org/doi/abs/10.1021/ja504441h

In life science water is the ubiquitous solvent, sometimes even called the “matrix of life”. There are more and more experimental and theoretical evidences that solvation water is not a passive spectator in biomolecular processes. New experimental techniques can quantify how water interacts with biomolecules and differs from “bulk” water. Terahertz (THz) absorption spectroscopy has turned out to be a powerful tool to study (bio)molecular hydration. The main concepts which have been developed in the recent years to describe the underlying solute-induced sub-picosecond dynamics of the hydration shell are reviewed. Moreover, we highlight recent findings that show the significance of hydrogen bond dynamics for the function of antifreeze proteins, and for molecular recognition. In all these examples a gradient of water motions towards functional sites of proteins is observed, the so-called “hydration funnel”. By means of molecular dynamics (MD) simulations, we provide new evidences for a specific water-protein coupling as the cause of the observed dynamical heterogeneity. The efficiency of the coupling at THz frequencies is explained in terms of a two-tier (short- and long-range) solute-solvent interaction