Localization phenomena in a DNA double helix structure : A twisted ladder model

TL;DR

This study models DNA double helix as a twisted ladder within a tight-binding framework, revealing how helicity influences electron localization and transport properties across different DNA sequences.

Contribution

It introduces a novel tight-binding model incorporating DNA helicity and analyzes its impact on electron localization and transport in various sequences.

Findings

Helicity enhances electron transport in DNA.

Existence of a disorder-independent critical hopping value.

Backbone energetics significantly affect transmission and I-V characteristics.

Abstract

In this work we propose a model for DNA double helix within the tight-binding framework that incorporates the helicity of the molecules. We have studied localization properties of three DNAsequences,the periodic poly(dG)-poly(dC) and poly(dA)-poly(dT) sequences and the random ATGCsequence, all of which are coupled to backbone withrandom site energies representing the environmentalfluctuations. We observe that due to helicity of DNA, electron transport is greatly enhancedand there exists almost a disorder-strength independent critical value of the hopping integral, thataccounts for helicity of DNA, for which the electronic states become maximally extended. We havealso investigated the effect of backbone energetics on the transmission and I-V characteristics of DNA.