Infrared probes for studying the structure and dynamics of biomolecules

The first step toward understanding most of the chemical and biological processes in condensed phases is to accurately describe solute-solvent interaction energy and to determine its spontaneous fluctuation amplitude and time scale. Various spectroscopic methods have thus been used to directly probe such solute-solvent interaction energies and dynamics. In particular, a combination of linear and nonlinear vibrational spectroscopy has provided intricate details on the molecular structures and conformational changes that are strongly affected by the magnitude and dynamic time scales of solute-solvent interactions. However, due to their small oscillator strengths, a lack of high sensitivity in comparison to fluorophores has been one of the obstacles. Another requirement for fully utilizing IR probes for quantitative bioassays is to develop a technique to sitespecifically introduce them into proteins and nucleic acids.