Stretching short DNAs in electrolytes.
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.
Wang
Jizeng
J
Max Planck Institute for Metals Research, Heisenbergstrasse 3, D-70569 Stuttgart, Germany. jz.wang@mf.mpg.de
Fan
Xiaojun
X
Gao
Huajian
H
D000465:Algorithms; D003198:Computer Simulation; D004247:DNA / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry*; D008962:Models, Theoretical; D009690:Nucleic Acid Conformation; D013314:Stress, Mechanical; D013816:Thermodynamics
D004573:Electrolytes; D004247:DNA