Thermodynamics of DNA loops with long-range correlated structural disorder

TL;DR

This paper investigates how long-range correlated structural disorder affects the thermodynamics and dynamics of DNA loops, revealing that such disorder promotes smaller loops and superdiffusive behavior, with implications for chromatin biology.

Contribution

It introduces a model incorporating long-range correlations in disorder and analyzes their impact on DNA loop formation and dynamics both numerically and analytically.

Findings

Long-range correlations favor smaller DNA loops.

LRC induce superdiffusive loop dynamics.

Potential implications for nucleosome positioning.

Abstract

We study the influence of a structural disorder on the thermodynamical properties of 2D-elastic chains submitted to mechanical/topological constraint as loops. The disorder is introduced via a spontaneous curvature whose distribution along the chain presents either no correlation or long-range correlations (LRC). The equilibrium properties of the one-loop system are derived numerically and analytically for weak disorder. LRC are shown to favor the formation of small loop, larger the LRC, smaller the loop size. We use the mean first passage time formalism to show that the typical short time loop dynamics is superdiffusive in the presence of LRC. Potential biological implications on nucleosome positioning and dynamics in eukaryotic chromatin are discussed.