Stretching Helical Macromolecules
We study the elasticity of a homopolypeptide under extension using Monte Carlo simulations based on the Wang-Landau algorithm. The effect of external mechanical forces is described with an extension of a model for helical polymers (V. Varshney et. al., Macromolecules 2004, 37, 8794). We find that the application of a mechanical force first increases the helix-to-coil transition temperature and then decreases it. This non-monotonic behavior is a consequence of a change in the nature of the helix-coil transition which becomes a helix-extended-coil transition for strong forces. We also find that the force-elongation curve at constant temperature displays three different behaviors depending on the temperature of the system. At temperatures below or slightly above the helix-coil transition temperature the force-elongation curve shows one or two coexistence regions, respectively. In these regions helical sequences and random coil domains coexist. At high temperatures our model recovers the elastic behavior of a random coil. We present a quantitative comparison with the theoretical results of Buhot and Halperin, and very good agreement is observed.
Carri, Gustavo, "Stretching Helical Macromolecules" (2005). Polymer Science Faculty Research. 198.
This document is currently not available here.