Volume 123, Number 6, September 2018
|Number of page(s)||7|
|Section||Interdisciplinary Physics and Related Areas of Science and Technology|
|Published online||15 October 2018|
Short DNA persistence length in a mesoscopic helical model
School of Science and Technology, University of Camerino - I-62032 Camerino (MC), Italy
Received: 8 June 2018
Accepted: 25 September 2018
The flexibility of short DNA chains is investigated via computation of the average correlation function between dimers which defines the persistence length. Path integration techniques have been applied to confine the phase space available to base pair fluctuations and derive the partition function. The apparent persistence lengths of a set of short chains have been computed as a function of the twist conformation both in the over-twisted and the untwisted regimes, whereby the equilibrium twist is selected by free energy minimization. The obtained values are significantly lower than those generally attributed to kilo-base long DNA. This points to an intrinsic helix flexibility at short length scales, arising from large fluctuational effects and local bending, in line with recent experimental indications. The interplay between helical untwisting and persistence length has been discussed for a heterogeneous fragment by weighing the effects of the sequence specificities through the non-linear stacking potential.
PACS: 87.14.gk – DNA / 87.15.A- – Theory, modeling, and computer simulation / 05.10.-a – Computational methods in statistical physics and nonlinear dynamics
© EPLA, 2018
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