Phase separation and dynamical arrest for particles interacting with mixed potentials--the case of globular proteins revisited

TL;DR

This study investigates the phase behavior and dynamical arrest of globular proteins, specifically lysozyme, using extended law of corresponding states and Mode Coupling Theory, revealing different factors influence phase separation and arrest lines.

Contribution

It demonstrates the limitations of the extended law of corresponding states in predicting arrest lines and highlights the role of attractive well depth in dynamical arrest for globular proteins.

Findings

ELCS accurately predicts binodal locations at various ionic strengths

ELCS fails to describe the arrest line accurately

Attractive well depth primarily determines the arrest line

Abstract

We examine the applicability of the extended law of corresponding states (ELCS) to equilibrium and non equilibrium features of the state diagram of the globular protein lysozyme. We provide compelling evidence that the ELCS correctly reproduces the location of the binodal for different ionic strengths, but fails in describing the location of the arrest line. We subsequently use Mode Coupling Theory (MCT) to gain additional insight into the origin of these observations. We demonstrate that while the critical point and the connected binodal and spinodal are governed by the integral features of the interaction potential described by the normalized second virial coefficient, the arrest line is mainly determined by the attractive well depth or bond strength. This article is published in Soft Matter. The reference is: DOI: 10.1039/c0sm01175d