Fig 3.

Maps calculated from the X-ray structure PDB: ID 1Z14 (A), and three cryo-EM structures of wildtype (B), L172T (C), and V40A (D) are surface rendered and displayed at a contour level of 1 sigma, with color coding according to radius (see color key). Overall exterior structures are remarkably similar between wildtype and the mutant VLP maps (upper panels). Zoomed views down the five-fold axis illustrate the vertices (middle panels). Both wildtype maps have a visible opening whereas the channel is occluded for the L172T and V40A mutants. Lower panels show the inner capsid surface of the five-fold channels, which have significantly different topologies. The calculated 1Z14 map has a smooth interior whereas the wildtype cryo-EM map has claw-like projections around the five-fold (black arrow) positioned near pit-like indentations (blue arrow) that extend out from ridges (green arrow). Rearrangements of the claw-like projections are seen in L172T and V40A (black arrows) along with the loss of the wildtype pit-like indentations.