Thermodynamics of nano-spheres encapsulated in virus capsids

TL;DR

This paper models the thermodynamics of nano-spheres encapsulated by virus capsids, highlighting how core charge and size influence capsid formation and structure through electrostatic and configurational interactions.

Contribution

It introduces a combined numerical and analytical framework to predict virus capsid assembly around charged nano-spheres based on their size and surface charge density.

Findings

Core charge and radius determine capsid size.

Phase diagram of assembly states constructed.

Electrostatic and configurational factors influence assembly.

Abstract

We investigate the thermodynamics of complexation of functionalized charged nano-spheres with viral proteins. The physics of this problem is governed by electrostatic interaction between the proteins and the nano-sphere cores (screened by salt ions), but also by configurational degrees of freedom of the charged protein N-tails. We approach the problem by constructing an appropriate complexation free energy functional. On the basis of both numerical and analytical studies of this functional we construct the phase diagram for the assembly which contains the information on the assembled structures that appear in the thermodynamical equilibrium, depending on the size and surface charge density of the nano-sphere cores. We show that both the nano-sphere core charge as well as its radius determine the size of the capsid that forms around the core.