Stiffer double-stranded DNA in two-dimensional confinement due to bending anisotropy

TL;DR

This study combines analytical methods and Monte Carlo simulations to demonstrate that bending anisotropy increases the persistence length of double-stranded DNA in 2D confinement, aligning with experimental observations and revealing twist-bend coupling effects.

Contribution

It provides a novel analytical and simulation-based analysis of how bending anisotropy affects DNA elasticity and conformation in 2D, highlighting implicit twist-bend coupling and kink formation.

Findings

Persistence length in 2D exceeds that in 3D for DNA.

Bending anisotropy causes implicit twist-bend coupling.

Kink formations with half helical turn periodicity occur in 2D.

Abstract

Using analytical approach and Monte-Carlo (MC) simulations, we study the elastic behaviour of the intrinsically twisted elastic ribbons with bending anisotropy, such as double-stranded DNA (dsDNA), in two-dimensional (2D) confinement. We show that, due to the bending anisotropy, the persistence length of dsDNA in 2D conformations is always greater than 3D conformations. This result is in consistence with the measured values for DNA persistence length in 2D and 3D in equal biological conditions. We also show that in 2D, an anisotropic, intrinsically twisted polymer exhibits an implicit twist-bend coupling, which leads to the kink formations with a half helical turn periodicity along the bent polymer.