Dynamics of water interacting with biomolecules

Life as we know it takes place in liquid water. This water is not merely a passive solvent, but plays an active role in many biological processes. Understanding the subtle interplay between water and biomolecules is therefore crucial for understanding the mechanics and chemistry of life. In this thesis, we present a series of spectroscopic experiments that elucidate the hydrogen-bond structure and dynamics of water molecules in solutions of different biologically relevant molecules. In particular, we studied solutions of sugars, globular proteins, and antifreeze glycoproteins, and water molecules confined in triglyceride oils. As a tool, we used vibrational pump-probe spectroscopy. This technique uses a short, intense infrared pump pulse to excite molecular vibrations that we can follow over time by monitoring the infrared absorption of a second, weaker probe pulse. The thus obtained time-resolved spectra provide information on for example the hydrogen-bond dynamics and the reorientation dynamics of water, which in turn allows insight in the molecular mechanism of different biological processes.