Volume 86, Number 5, June 2009
Article Number 53002
Number of page(s) 6
Section Atomic, Molecular and Optical Physics
Published online 24 June 2009
EPL, 86 (2009) 53002
DOI: 10.1209/0295-5075/86/53002

Kinetics of the helix-coil transition

A. E. Allahverdyan1, S. G. Gevorkian1 and A. Simonian2

1   Yerevan Physics Institute - Alikhanian Brothers Street 2, Yerevan 375036, Armenia
2   Materials Research and Education Center - 275 Wilmore Auburn University, Auburn AL 36849-5341, USA

received 10 April 2009; accepted in final form 28 May 2009; published June 2009
published online 24 June 2009

Based on the Zimm-Bragg model we study cooperative helix-coil transition driven by a finite-speed change of temperature. There is an asymmetry between the coil $\rightarrow $ helix and helix $\rightarrow $ coil transition: the latter is displayed already for finite speeds, and takes shorter time than the former. This hysteresis effect has been observed experimentally, and it is explained here via quantifying system's stability in the vicinity of the critical temperature. A finite-speed cooling induces a non-equilibrium helical phase with the correlation length larger than in equilibrium. In this phase the characteristic length of the coiled domain and the non-equilibrium specific heat can display an anomalous response to temperature changes. Several pertinent experimental results on the kinetics of helical biopolymers are discussed in detail.

36.20.-r - Macromolecules and polymer molecules.
36.20.Ey - Conformation (statistics and dynamics).
05.20.Dd - Kinetic theory.

© EPLA 2009