Fig. 3: Intra- and inter-capsomer interactions.

a Cartoon representation of the hexamer capsomer 1 viewed from outside (left) and inside (right) the viral capsid. One of the six MCP subunits is colored as in Fig. 2a. b Zoomed-in view of the boxed region in a, showing the β-strand interactions formed by two neighboring MCP subunits. c Zoomed-in view of the six-α-helix bundle. The structures are shown as ribbon diagram (left), molecular surface colored according to the electrostatic potential (middle) and molecular surface colored according to hydrophobicity (right). d Structure of hexameric capsomers 1, 2 and 3. Subunit a is shown as ribbon diagram while the other subunits (b to r) are shown as molecular surfaces. q2 and q3 indicate a quasi-two-fold axis and a quasi-three-fold axis, respectively. e Zoomed-in view of the boxed region in (d) showing the ribbon diagrams of the I-domain dimer and surrounding components. Blue dashed lines indicate putative salt bridges. Loops K218–Q232 and P352–R359 are highlighted in orange. f The left panel is a zoomed-in view showing the interaction between the loop K218–Q232 of subunit h (highlighted in orange) and the I domain of subunit b (shown as molecular surface). The right panel shows the interaction between the loop P352–R359 of subunit g (highlighted in orange) and the I domain of subunit d. g Zoomed-in view of the area around the quasi-three-fold axis showing: (1) the interactions between the three adjacent P-domain loop L693–T703 (highlighted in orange) and (2) the interactions between the P-domain loop L693–T703 and the I-domain linker from a neighboring capsomer. Hex, hexameric capsomer. NTA, N-terminal arm. CTA, C-terminal arm.