Nonequilibrium self-assembly dynamics of icosahedral viral capsids packaging genome or polyelectrolyte
Résumé
The survival of viruses partly relies on their ability to self-assemble inside host cells. Although coarse-grained simulations have identified different pathways leading to assembled virions from their components, experimental evidence is severely lacking. Here, we use time-resolved small-angle X-ray scattering to uncover the nonequilibrium self-assembly dynamics of icosahedral viral capsids packaging their full RNA genome. We reveal the formation of amorphous complexes via an en masse pathway and their relaxation into virions via a synchronous pathway. The binding energy of capsid subunits on the genome is moderate ($\sim$7$k_B$ T$_0$ , with $k_B$ the Boltzmann constant and T$_0$ = 298 K, the room temperature), while the energy barrier separating the complexes and the virions is high ($\sim$20$k_B$ T$_0$). A synthetic polyelectrolyte can lower this barrier so that filled capsids are formed in conditions where virions cannot build up. We propose a representation of the dynamics on a free energy landscape.
Origine : Publication financée par une institution
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