Phase Separation in Peptide Aggregation Processes - Multicanonical Study of a Mesoscopic Model

TL;DR

This study uses multicanonical simulations to explore peptide aggregation, revealing phase separation-like behavior in small heteropolymer systems and emphasizing the microcanonical perspective over the canonical approach.

Contribution

It introduces a mesoscopic model and demonstrates the relevance of microcanonical analysis for small peptide systems undergoing aggregation.

Findings

Aggregation transition resembles first-order phase separation

Temperature is not a suitable control parameter in the transition region

Microcanonical interpretation is more appropriate for small systems

Abstract

We have performed multicanonical computer simulations of a small system of short protein-like heteropolymers and found that their aggregation transition possesses similarities to first-order phase separation processes. Not being a phase transition in the thermodynamic sense, the observed folding-binding behavior exhibits fascinating features leading to the conclusion that the temperature is no suitable control parameter in the transition region. More formally, for such small systems the microcanonical interpretation is more favorable than the typically used canonical picture.