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Updated: May 22, 2026

In Vitro Disassembly of Influenza A Virus Capsids by Gradient Centrifugation
Published on: March 27, 2016
Virus capsid dissolution studied by microsecond molecular dynamics simulations
Daniel S D Larsson1, Lars Liljas, David van der Spoel
1Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
Abstract:
Dissolution of many plant viruses is thought to start with swelling of the capsid caused by calcium removal following infection, but no high-resolution structures of swollen capsids exist. Here we have used microsecond all-atom molecular simulations to describe the dynamics of the capsid of satellite tobacco necrosis virus with and without the 92 structural calcium ions. The capsid expanded 2.5% upon removal of the calcium, in good agreement with experimental estimates. The water permeability of the native capsid was similar to that of a phospholipid membrane, but the permeability increased 10-fold after removing the calcium, predominantly between the 2-fold and 3-fold related subunits. The two calcium binding sites close to the icosahedral 3-fold symmetry axis were pivotal in the expansion and capsid-opening process, while the binding site on the 5-fold axis changed little structurally. These findings suggest that the dissociation of the capsid is initiated at the 3-fold axis.
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