(508a) Elucidating Molecular Details of Protein Liquid-Liquid Phase Separation By a Coarse-Grained Model

Authors: 
Dignon, G. L., Lehigh University
Mittal, J., Lehigh University
Best, R., National Institutes of Health
Zheng, W., NIH
Recently, much interest has been generated in the biological phenomenon of of phase-separated assemblies composed of protein and RNA. These assemblies are ubiquitous within the eukaryotic cell, making up structures such as membraneless organelles and stress granules, and have been shown to display liquid-like properties including dripping, rapid internal rearrangement, and relaxation to a spherical shape. Due to the scale of these systems, atomistic simulations would be severely limited in scope, thus motivating the development of appropriate coarse-grained models. We propose a CÉ‘-based model in which relative inter-residue interactions are tuned based on their hydrophobicity and parameterized to capture dimensions of intrinsically disordered proteins. We show that our model is able to capture concentration and temperature dependent phase separation between dilute and dense liquid states. The model is further used to obtain thermodynamic phase diagrams for many systems of interest and changes in the phase behavior due to changes in the protein sequence or/and length.