Figure 3. Protruding knob-like densities.

(a) An overall arrangement of the knob-like densities (green) protruding from the capsid surface (grey model) formed by the major capsid protein gp39, where the pentameric vertices are shown in dark grey. Two triangular (T) faces are annotated as blue, pink and yellow hexagons per T-face to show strict icosahedral three- and two-fold symmetry. (b) A view of the strict icosahedral three-fold showing the arrangement of the protruding densities (green). The three knob-like densities (green) are labelled such that I faces the vertex, while J faces the neighbouring hexamer and H lies at the centre of the hexamer. (c) A view of the strict icosahedral two-fold showing the relative arrangement of I/H/J.