Mer. 21/04/2021 15:00 autre
CARLON Enrico (Soft Matter and Biophysics (KU Leuven, Belgium))
Length-scale dependent DNA elasticity and the non-local Twistable Wormlike chain model
We investigate the influence of non-local couplings on the torsional and bending elasticities of DNA. Such couplings have been observed in the past by several simulation studies. Here, we use a description of DNA conformations based on the variables tilt, roll and twist. Our analysis of both coarse-grained (oxDNA) and all-atom models indicates that these share strikingly similar features: there are strong off-site couplings for tilt-tilt and twist-twist, while they are much weaker in the roll-roll case. By developing an analytical framework to estimate bending and torsional persistence lengths in non-local DNA models, we show how off-site interactions generate a length scale dependent elasticity. Based on the simulation generated elasticity data the theory predicts a significant length scale dependent effect on torsional fluctuations, but only a modest effect on bending fluctuations. These results are in agreement with experiments probing DNA mechanics from single base pair to kilobase pair scales.
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