WASHINGTON, D.C., December 14, 2015 -- In a biological system, the ratio of water-to-non-water molecules, known as the hydration level, influences both the arrangement of biomolecules and the strength of the electric interactions that occur between biomolecules, free ions, and functional groups, which are groups of atoms within molecules that strongly influence the molecules' chemical properties. To isolate the contribution of water to the vibrational fluctuations that occur between DNA, bulk water, and the charged biomolecular interface between the two, researchers at the Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy in Berlin have performed two-dimensional spectroscopic analyses on double-stranded DNA helices at different hydration levels.