Mechanical Limits of Viral Capsids

Dr. Mathias Buenemann
Biophysics, UCSD


Viral shells are extremely stable nano-containers. They are able to sustain internal pressures of ~50 atm as well as point forces up to ~1 nN. We have numerically studied the stability of viral capsid in terms of a single dimensionless parameter, the Foppl-von-Karman (FvK) number \gamma. We are able to attribute the experimentally observed bimodal distribution of spring constants to the geometry of viral capsids. A criterion for capsid breakage is defined, which explains well the experimentally observed rupture. From our numerics, we find a \gamma^{2/3} dependence of the rupture force for spherical viruses. The influence of internal pressure on the stability of capsids is analyzed. Finally, we suggest a method for determining the spatial distribution of protein binding potentials from the spatial distribution of rupture events.