Tautomeric Transitions in DNA

TL;DR

This paper models DNA tautomeric transitions as coupled classical and quantum processes, revealing soliton-like solutions that could explain mutation mechanisms and suggest mutation induction via infrared irradiation.

Contribution

It introduces a novel combined classical-quantum model of DNA tautomeric transitions, showing how soliton solutions depend on DNA structure and may influence mutation processes.

Findings

Soliton-like solutions depend on DNA's elastic and torsional properties.

Discrete breathers are significantly affected by the interplay of structural constants.

Simulations indicate possible mutation accumulation at specific DNA sites over microsecond timescales.

Abstract

We study the tautomeric transitions in base pairs of DNA considering elastic properties of DNA as classical and tunneling of protons as quantum, and show that the dynamics of the transitions admits of soliton like solutions whose shape and size strongly depend on the structure of the double helix. In particular, we have found that the set of discrete breathers can be drastically modified by the interplay of the torsional and elastic constants. Our results may have a bearing upon substitution mutagenesis within the framework of Watson-Crick's approach, and in this respect the breather soliton could describe conformations corresponding to point mutations. The numerical simulation of soliton dynamics suggests that an initial distribution of base pairs with low probability of mutation per pair but of a sufficiently large number of base pairs involved, could move and gather around a site so as to form a set of base pairs with high probability of mutation, for a period of time approximately 1 musec. We suggest that the irradiation of DNA at frequencies of the proton tunneling, that is in infra-red region, could cause mutations.