Effect of external stress on the thermal melting of DNA

TL;DR

This paper investigates how external mechanical stress influences the thermal melting behavior of DNA, revealing that pulling forces significantly alter the denaturation transition and its underlying thermodynamics.

Contribution

It provides a detailed analysis of the effects of external stretching forces on DNA melting, including considerations of excluded volume and force-induced separation mechanisms.

Findings

Stretching force lowers the melting temperature of DNA.

External stress modifies the denaturation transition dynamics.

Force application can induce separation of DNA strands at lower temperatures.

Abstract

We discuss the effects of external stress on the thermal denaturation of homogeneous DNA. Pulling double-stranded DNA at each end exerts a profound effect on the thermal denaturation, or melting, of a long segment of this molecule. We discuss the effects on this transition of a stretching force applied to opposite ends of one of the DNA strands, including full consideration of the consequences of excluded volume, the analysis of which is greatly simplified in this case. We also discuss the interplay of thermal denaturation and force-generated separation when the tension is generated by a force at the end of the duplexed strands and an equal and opposite force is applied to the other end of the second strand.