Open Access

ARTICLE

Stretching Short DNAs in Electrolytes

Jizeng Wang^1,2, Xiaojun Fan², Huajian Gao²

1 E-mail: jz.wang@mf.mpg.de
2 Max Planck Institute for Metals Research, Heisenbergstrasse 3, D-70569 Stuttgart, Germany.

Molecular & Cellular Biomechanics 2006, 3(1), 13-20. https://doi.org/10.3970/mcb.2006.003.013

Abstract

This paper is aimed at a combined theoretical and numerical study of the force-extension relation of a short DNA molecule stretched in an electrolyte. A theoretical formula based on a recent discrete wormlike chain (WLC) model of Kierfeld et al. (Eur. Phys. J. E, Vol. 14, pp.17-34, 2004) and the classical OSF mean-field theory on electrostatic stiffening of a charged polymer is numerically verified by a set of Brownian dynamics simulations based on a generalized bead-rod (GBR) model incorporating long-ranged electrostatic interactions via the Debye-Hueckel potential (DH). The analysis indicates that the stretching of a short DNA can be well described as a WLC with a constant effective persistent length. This contrasts the behavior of long DNA chains that are known to exhibit variable persistent lengths depending on the ion concentration levels and force magnitudes.

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