Phase Diagram of alpha-Helical and beta-Sheet Forming Peptides

TL;DR

This study uses Monte Carlo simulations with a coarse-grained model to map the phase diagram of peptides forming alpha-helices and beta-sheets, revealing multiple metastable phases and hierarchical stability.

Contribution

It introduces a novel simulation approach to determine the phase behavior of peptide motifs, highlighting metastable states and phase hierarchy.

Findings

Liquidlike phases are metastable compared to fibrillar phases

Multiple metastable peptide phases exist

Hierarchy of metastability among phases

Abstract

The intrinsic property of proteins to form structural motifs such as alpha-helices and beta-sheets leads to a complex phase behavior in which proteins can assemble into various types of aggregates including crystals, liquidlike phases of unfolded or natively folded proteins, and amyloid fibrils. Here we use a coarse-grained protein model that enables us to perform Monte Carlo simulations for determining the phase diagram of natively folded alpha-helical and unfolded beta-sheet forming peptides. The simulations reveal the existence of various metastable peptide phases. The liquidlike phases are metastable with respect to the fibrillar phases, and there is a hierarchy of metastability.