Europhys. Lett.
Volume 62, Number 5, June 2003
Page(s) 760 - 766
Section Interdisciplinary physics and related areas of science and technology
Published online 01 May 2003
DOI: 10.1209/epl/i2003-00336-3
Europhys. Lett., 62 (5) , pp. 760-766 (2003)

The bend stiffness of S-DNA

C. Storm and P. C. Nelson

Department of Physics and Astronomy, University of Pennsylvania Philadelphia, PA 19104, USA

(Received 10 December 2002; accepted in final form 8 April 2003)

We formulate and solve a two-state model for the elasticity of nicked, double-stranded DNA that borrows features from both the Worm Like Chain and the Bragg-Zimm model. Our model is computationally simple, and gives an excellent fit to recent experimental data through the entire overstretching transition. The fit gives the first value for the bending stiffness of the overstretched state as about $12\un{nm}\cdot k_{\ab{B}}T$, a value quite different from either B-form or single-stranded DNA.

87.15.La - Biomolecules: Mechanical properties.
87.15.Aa - Biomolecules: Theory and modeling; computer simulation.
82.35.Lr - Physical properties of polymers.

© EDP Sciences 2003