The structure of Pariacoto virus reveals a dodecahedral cage of duplex RNA

The 3.0 Angstrom resolution crystal structure of Pariacoto virus (PaV) reve als extensive interactions between portions of the viral RNA genome and the icosahedral capsid. Under the protein shell of the T = 3 quasi equivalent capsid lies a dodecahedral cage composed of RNA duplex that accounts for si milar to 35% of the single-stranded RNA genome. The highly basic N-terminal regions (residues 7-54) of the subunits, forming pentamers (A subunits) ar e clearly visible in the density map and make numerous interactions with th e RNA cage. The C-terminal segments (residues 394-401) of the A subunits li e in channels near the quasi three-fold axes. Electron cryo-microscopy and image reconstruction of PaV particles clearly show the dodecahedral RNA cag e.