posted on 2020-11-09, 14:07authored byHemani Chhabra, Garima Mishra, Yijing Cao, Domen Prešern, Enrico Skoruppa, Maxime M. C. Tortora, Jonathan P. K. Doye
To
study the elastic properties of rodlike DNA nanostructures,
we perform long simulations of these structures using the oxDNA coarse-grained
model. By analyzing the fluctuations in these trajectories, we obtain
estimates of the bend and twist persistence lengths and the underlying
bend and twist elastic moduli and couplings between them. Only on
length scales beyond those associated with the spacings between the
interhelix crossovers do the bending fluctuations behave like those
of a wormlike chain. The obtained bending persistence lengths are
much larger than that for double-stranded DNA and increase nonlinearly
with the number of helices, whereas the twist moduli increase approximately
linearly. To within the numerical error in our data, the twist-bend
coupling constants are of order zero. That the bending persistence
lengths that we obtain are generally somewhat higher than in experiment
probably reflects both that the simulated origamis have no assembly
defects and that the oxDNA extensional modulus for double-stranded
DNA is too large.