Effects of long range interactions on the conformational statistics of short polypeptide chains generated by a Monte Carlo method

Publisher Website
Google Scholar
Abstract
Distributions of end‐to‐end distances and characteristic ratios are calculated for short poly‐l‐ala and poly‐gly chains generated by a Monte Carlo method based on the procedure elaborated by Metropolis et al. Interactions between all the atoms of the chain are taken into account for the conformational energy calculations. The characteristic ratios obtained with the complete set of interaction terms are much smaller than those calculated according to the method of Flory. This collapse of the chain is interpreted as due to a bad solvent. Results in agreement with Flory’s are obtained by modifying the potential functions to simulate the behavior of the chain in a ϑ or even a good solvent. In this case an excluded volume effect appears for poly‐gly chains, whereas poly‐l‐ala chains are too stiff to present this effect with less than 16 residues.