Helix Formation and Folding in an Artificial Peptide

TL;DR

This study uses advanced simulations to explore how an artificial peptide folds, revealing a two-step process involving initial helix formation followed by re-arrangement into a U-shape structure.

Contribution

It provides detailed free-energy landscapes of peptide folding, highlighting the sequence of structural transitions in an artificial peptide.

Findings

Folding occurs in two steps: helix formation then re-arrangement.

Helix formation precedes the U-like structure.

The free-energy landscape varies with temperature.

Abstract

We study the relation between $\alpha$-helix formation and folding for a simple artificial peptide, Ala$_{10}$-Gly$_5$-Ala$_{10}$. Our data rely on multicanonical Monte Carlo simulations where the interactions among all atoms are taken into account. The free-energy landscape of the peptide is evaluated for various temperatures. Our data indicate that folding of this peptide is a two-step process: in a first step two $\alpha$-helices are formed which afterwards re-arrange themselves into a U-like structure.