Structural correlations and melting of B-DNA fibres

TL;DR

This study uses neutron scattering, calorimetry, electrophoresis, and optical methods to analyze the structural changes and correlations in B-DNA fibers during thermal melting, providing spatial insights into the denaturation process.

Contribution

It introduces a novel application of neutron scattering to measure structural correlations in DNA fibers near melting, complemented by a mesoscopic model analysis.

Findings

Neutron scattering reveals the size of double-helix regions near melting.

Bragg peak width and intensity vary with temperature, indicating structural changes.

The combined data support a one-dimensional mesoscopic model of DNA melting.

Abstract

Despite numerous attempts, the understanding of the thermal denaturation of DNA is still a challenge due to the lack of structural data at the transition since standard experimental approaches to DNA melting are made in solution and do not provide spatial information. We report a measurement using neutron scattering from oriented DNA fibres to determine the size of the regions that stay in the double-helix conformation as the melting temperature is approached from below. A Bragg peak from the B-form of DNA has been observed as a function of temperature and its width and integrated intensity have bean measured. These results, complemented by a differential calorimetry study of the melting of B DNA fibres as well as electrophoresis and optical observation data, are analysed in terms of a one-dimensional mesoscopic model of DNA.