Denaturation of Heterogeneous DNA

TL;DR

This paper investigates how sequence heterogeneity affects DNA denaturation, finding minimal impact in simple models but significant effects in more realistic ones, leading to multi-step melting phenomena observed experimentally.

Contribution

It demonstrates the importance of backbone stiffness in modeling DNA melting, revealing multi-step denaturation consistent with experimental observations.

Findings

Sequence heterogeneity has negligible effect in simple models.

Backbone stiffness amplifies heterogeneity effects.

Model reproduces multi-step melting observed experimentally.

Abstract

The effect of heterogeneous sequence composition on the denaturation of double stranded DNA is investigated. The resulting pair-binding energy variation is found to have a negligible effect on the critical properties of the smooth second order melting transition in the simplest (Peyrard-Bishop) model. However, sequence heterogeneity is dramatically amplified upon adopting a more realistic treatment of the backbone stiffness. The model yields features of ``multi-step melting'' similar to those observed in experiments.