  The functioning of double-stranded (ds) nucleic acids (NAs) in cellular
processes is strongly mediated by their elastic response. These processes
involve proteins that interact with dsDNA or dsRNA and distort their
structures. The perturbation of the elasticity of NAs arising from these
deformations is not properly considered by most theoretical frameworks. In this
work, we introduce a novel method to assess the impact of mechanical stress on
the elastic response of dsDNA and dsRNA through the analysis of the
fluctuations of the double helix. Application of this approach to atomistic
simulations reveals qualitative differences in the force dependence of the
mechanical properties of dsDNA with respect to those of dsRNA, which we relate
to structural features of these molecules by means of physically-sound
minimalistic models.
