How do self-assembled virus-like particles break open to expose their cargo?

Viral capsids perform the competing functions of protecting their genome from the environment and exposing it during infection of a host cell. Compared to the process of forming a protective capsid, which for many viruses occurs through self-assembly, the process of exposing the genome is less well studied. Because the assembled state is a free-energy minimum, viral capsids must take advantage of new chemical environments in their hosts to disrupt their intermolecular interactions and expose their interior. By measuring the rate of binding of fluorescent molecules to the viral RNA, we indirectly explore the effects of chemical environments on capsid integrity. I will discuss the results of these experiments and their interpretation in terms of structural changes such as breathing modes.