Inverse Temperature Dependence of Nuclear Quantum Effects in DNA Base Pairs

TL;DR

This study investigates how nuclear quantum effects influence hydrogen bond strengths in DNA base pairs, revealing temperature-dependent behaviors that can either strengthen or weaken these bonds, with implications for understanding molecular interactions.

Contribution

The paper introduces a model predicting the temperature dependence of nuclear quantum effects on hydrogen bonds, supported by ab initio path integral molecular dynamics simulations.

Findings

NQEs can both strengthen and weaken hydrogen bonds depending on temperature.

NQEs have a smaller impact at cryogenic temperatures than at room temperature.

A simple model is proposed to predict NQEs' temperature dependence in hydrogen bonds.

Abstract

Despite the inherently quantum mechanical nature of hydrogen bonding, it is unclear how nuclear quantum effects (NQEs) alter the strengths of hydrogen bonds. With this in mind, we use ab initio path integral molecular dynamics to determine the absolute contribution of NQEs to the binding in DNA base pair complexes, arguably the most important hydrogen-bonded systems of all. We find that depending on the temperature, NQEs can either strengthen or weaken the binding within the hydrogen-bonded complexes. As a somewhat counterintuitive consequence, NQEs can have a smaller impact on hydrogen bond strengths at cryogenic temperatures than at room temperature. We rationalize this in terms of a competition of NQEs between low-frequency and high-frequency vibrational modes. Extending this idea, we also propose a simple model to predict the temperature dependence of NQEs on hydrogen bond strengths in general.