Transition between random and periodic electron currents on a DNA chain

TL;DR

This study models electron motion along DNA chains, revealing that external energy can induce either random or periodic electron currents, depending on excitation site, indicating complex electrodynamic interactions in DNA.

Contribution

The paper introduces a model combining Davydov and Holstein-Fröhlich frameworks to analyze DNA electron transfer, highlighting sequence-dependent current behaviors under external energy.

Findings

Electron currents can be broad or sharply peaked in frequency spectrum.

Charge transfer depends on excitation site and external energy.

DNA-electromagnetic interactions may influence biological processes.

Abstract

By resorting to a model inspired to the standard Davydov and Holstein-Fr\"ohlich models, in the present paper we study the motion of an electron along a chain of heavy particles modelling a sequence of nucleotides proper to a DNA fragment. Starting with a model Hamiltonian written in second quantization, we use the Time Dependent Variational Principle to work out the dynamical equations of the system. It is found that under the action of an external source of energy transferred to the electron, and according to the excitation site, the electron current can display either a broad frequency spectrum or a sharply peaked frequency spectrum. This sequence-dependent charge transfer phenomenology is suggestive of a potentially rich variety of electrodynamic interactions of DNA molecules under the action of electron excitation. This could imply the activation of interactions between DNA and transcription factors, or between DNA and external electromagnetic fields.