The role of elastic energy in the formation of highly symmetric viral shells

Virus assembly is a fascinating biological process in which hundreds, or even thousands, of proteins come together simultaneously to create a highly symmetric nano-structure. What's particularly remarkable is that viruses can complete this assembly in a matter of seconds to minutes. However, this rapidity also presents a challenge when it comes to understanding the underlying mechanisms of the assembly pathway. To date, two plausible pathways have been proposed: (i) en masse assembly and (ii) nucleation and growth. Despite many years of investigation, numerous questions persist about the mechanisms and conditions that govern these pathways.

In this study, we introduce a coarse-grained model that enables us to explore the assembly pathway while taking into account the elastic energy involved in the growth of the viral shell. Our primary focus is on determining the circumstances under which either nucleation or en masse assembly is more likely to occur. We find that these pathways can be significantly influenced by the reversible rate, which relates to conformational changes in binding proteins. Additionally, we present our research related to the impact of the secondary structures of RNA on the assembly pathway and the morphology of the capsid. In agreement with X-ray scattering measurements on hepatitis B virus capsids, the presence of RNA significantly accelerates the kinetics of shell formation.