(493b) Dynamic Pathways for Viral Capsid Assembly

The assembly of protein subunits into a virus capsid is remarkable. In many different organisms and environments, capsids avoid kinetic and thermodynamic traps to assemble rapidly and with high fidelity. Identifying the features of capsid components that enable such robust assembly could play a critical role in the development of anti-viral strategies and drug delivery vehicles. We develop a class of models with which we simulate the assembly of particles into T1 capsid-like objects using Brownian dynamics. By simulating assembly for many different values of system parameters, we vary the forces that drive assembly. For some ranges of parameters, assembly is facile, while for others, assembly is dynamically frustrated by kinetic traps corresponding to malformed or incompletely formed capsids. Our simulations sample many independent trajectories at various capsomer concentrations, allowing for statistically meaningful conclusions. Depending on subunit (i.e., capsomer) geometries, successful assembly proceeds by several mechanisms involving binding of intermediates of various sizes. We discuss the relationship between these mechanisms and experimental evaluations of capsid assembly processes.