Issue
EPL
Volume 85, Number 3, February 2009
Article Number 38003
Number of page(s) 5
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/85/38003
Published online 09 February 2009
EPL, 85 (2009) 38003
DOI: 10.1209/0295-5075/85/38003

Can re-entrance be observed in force-induced transitions?

Sanjay Kumar

Department of Physics, Banaras Hindu University - Varanasi 221 005, India

yashankit@yahoo.com

received 6 May 2008; accepted in final form 9 January 2009; published February 2009
published online 9 February 2009

Abstract
A large conformational change in the reaction co-ordinate and the role of the solvent in the formation of base pairing are combined to settle a long-standing issue, i.e. prediction of re-entrance in the force-induced transition of DNA. A direct way to observe the re-entrance, i.e. a strand that goes to the closed state from the open state and again to the open state with increasing temperature, appears difficult to be achieved in the laboratory. An experimental protocol (in direct way) in the constant force ensemble is being proposed for the first time that will enable the observation of the re-entrance behavior in the force-temperature plane. Our exact results for a small oligonucleotide that forms a hairpin structure provide the evidence that re-entrance can be observed.

PACS
82.35.Jk - Copolymers, phase transitions, structure.
36.20.Ey - Conformation (statistics and dynamics).
64.90.+b - Other topics in equations of state, phase equilibria, and phase transitions.

© EPLA 2009