Force fluctuations in stretching a tethered polymer

Abstract

The recently proposed fluctuation relation in unfolding forces [Phys. Rev. E $84$, $060101$(R) $(2011)$] is re-examined taking into account the explicit time dependence of the force distribution. The stretching of a tethered Rouse polymer is exactly solved and the ratio of the probabilities of positive to negative forces is shown to be an exponential in force. Extensive steered molecular dynamics simulations of unfolding of deca alanine peptide confirm the form of fluctuation relation proposed earlier, but with explicit correct time dependence of unfolding forces taken into account. From exact calculations and simulations, a linear dependence of the constant in the exponential of the fluctuation relation on average unfolding forces and inverse temperature is proposed.

5 pages, 4 figures

References in corpus (5)

• An Extension of the Fluctuation Theorem
• Stationary and Transient Work-Fluctuation Theorems for a Dragged Brownian Particle
• Power and heat fluctuation theorems for electric circuits
• A fluidized granular medium as an instance of the Fluctuation Theorem
• Reconstructing the free energy landscape of a polyprotein by single-molecule experiments