Issue 7, 2021

Quantum and classical effects in DNA point mutations: Watson–Crick tautomerism in AT and GC base pairs

Abstract

Proton transfer along the hydrogen bonds of DNA can lead to the creation of short-lived, but biologically relevant point mutations that can further lead to gene mutation and, potentially, cancer. In this work, the energy landscape of the canonical A–T and G–C base pairs (standard, amino–keto) to tautomeric A*–T* and G*–C* (non-standard, imino–enol) Watson–Crick DNA base pairs is modelled with density functional theory and machine-learning nudge-elastic band methods. We calculate the energy barriers and tunnelling rates of hydrogen transfer between and within each base monomer (A, T, G and C). We show that the role of tunnelling in A–T tautomerisation is statistically unlikely due to the presence of a small reverse reaction barrier. On the contrary, the thermal populations of the G*–C* point mutation could be non-trivial and propagate through the replisome. For the direct intramolecular transfer, the reaction is hindered by a substantial energy barrier. However, our calculations indicate that tautomeric bases in their monomeric form have remarkably long lifetimes.

Graphical abstract: Quantum and classical effects in DNA point mutations: Watson–Crick tautomerism in AT and GC base pairs

Supplementary files

Article information

Article type
Paper
Submitted
05 11 2020
Accepted
29 1 2021
First published
29 1 2021
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2021,23, 4141-4150

Quantum and classical effects in DNA point mutations: Watson–Crick tautomerism in AT and GC base pairs

L. Slocombe, J. S. Al-Khalili and M. Sacchi, Phys. Chem. Chem. Phys., 2021, 23, 4141 DOI: 10.1039/D0CP05781A

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