# Noncovalent Interactions of Hydrated DNA and RNA Mapped by 2D-IR Spectroscopy

## TL;DR

This paper uses 2D-IR spectroscopy combined with theoretical and simulation approaches to explore the noncovalent hydration interactions and dynamics of DNA and RNA molecules, revealing femtosecond water shell fluctuations and electric field behaviors.

## Contribution

It introduces a comprehensive analysis of hydrated DNA and RNA using 2D-IR spectroscopy alongside theoretical calculations and simulations, providing new insights into their hydration dynamics.

## Key findings

- Femtosecond fluctuation dynamics of the water shell
- Short-range Coulomb interactions dominate hydration behavior
- Interfacial electric fields exhibit measurable fluctuation amplitudes

## Abstract

Biomolecules couple to their aqueous environment through a variety of noncovalent interactions. Local structures at the surface of DNA and RNA are frequently determined by hydrogen bonds with water molecules, complemented by non-specific electrostatic and many-body interactions. Structural fluctuations of the water shell result in fluctuating Coulomb forces on polar and/or ionic groups of the biomolecular structure and in a breaking and reformation of hydrogen bonds. Two-dimensional infrared (2D-IR) spectroscopy of vibrational modes of DNA and RNA gives insight into local hydration geometries, elementary molecular dynamics, and the mechanisms behind them. In this chapter, recent results from 2D-IR spectroscopy of native and artificial DNA and RNA are presented, together with theoretical calculations of molecular couplings and molecular dynamics simulations. Backbone vibrations of DNA and RNA are established as sensitive noninvasive probes of the complex behavior of hydrated helices. The results reveal the femtosecond fluctuation dynamics of the water shell, the short-range character of Coulomb interactions, and the strength and fluctuation amplitudes of interfacial electric fields.