Issue
EPL
Volume 77, Number 6, March 2007
Article Number 68001
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/77/68001
Published online 27 February 2007
EPL, 77 (2007) 68001
DOI: 10.1209/0295-5075/77/68001

Stretching helical nano-springs at finite temperature

H. Wada and R. R. Netz

Physics Department, Technical University Munich - 85748 Garching, Germany


received 5 December 2006; accepted in final form 25 January 2007; published March 2007
published online 27 February 2007

Abstract
Using dynamic simulations and analytic methods, we study the elastic response of a helical filament subject to uniaxial tension over a wide range of bend and twist persistence length. A low-pitch helix at low temperatures exhibits a stretching instability and the force-extension curve consists of a sequence of spikes. At elevated temperature (i.e. small persistence lengths) the helix melts and a pronounced force plateau is obtained in the fixed-extension ensemble. The torque boundary condition significantly affects the resulting elastic properties.

PACS
87.15.-v - Biomolecules: structure and physical properties.
62.25.+g - Mechanical properties of nanoscale materials.
82.37.Gk - STM and AFM manipulations of a single molecule.

© Europhysics Letters Association 2007