Fig. 2: Interaction details between capsomers.

A Capsomer network containing the interfaces around the five-, three- and twofold axes, as denoted by a black pentagon, triangle, and oval, respectively. One penton (P1) and four hexons (H1 to H4) are included in the interaction analysis. Anti-parallel N-arms are involved in the inter-capsomeric interactions between the penton and hexon MCPs (B) and between two hexon MCPs (C) via extension to neighbouring capsomers. D, E Interaction patterns near the threefold axis are viewed from outside. Interaction details for one-third of the interface in (D) are shown in (E). An interaction network of hydrogen bonds is demarcated by yellow dashed lines. F Electrostatic potential surface representation of the same region as in (D) except for the E-loops (cartoon representation). The outline of the E-loops depicted by the surface are highlighted as black lines. G Electrostatic potential surfaces of E-loops that observed by rotation 180° through (F). Complementary electrostatic potentials are observed near the tips of the E-loops. H Electrostatic potential surface representation of two adjacent hexamer MCP monomers. Complementary electrostatic potentials occur at the interface of monomer A (top right) and monomer B (bottom right). The electrostatic potential scale is shown in the colour bar (red–white–blue).