FIG. 3.

Hexon trimer colored by sequence diversity. Layers of the trimeric hexon molecule displayed as ribbons. The two columns show hexon slices viewed along the molecular threefold axis. The arrows indicate the direction of view from either the virion exterior top to bottom (left) or from the virion interior bottom to top (right). The structures are colored by sequence diversity from blue (conserved) to yellow (less conserved) to red (not conserved). The jellyrolls V1 and V2 and their α₁ helices are labeled. Note that the size of the hexon's pseudohexameric base is dictated by structural elements, such as V1-α1 and V2-α1, which separate the jellyrolls. A PDB file of the hexon trimer with temperature factors (B factors) representing sequence diversity is available for download at http://bioinfo.wistar.upenn.edu/pub/RKB_hexon_var.pdb.