FIG 3.

(a) A calculated procapsid map was subtracted from the EV71 procapsid-Fab 22A12 complex to generate a difference map, which is shown surface rendered at 1 σ, indicating strong Fab density (blue) and interior noise (red). (b) The crystal structures of the EV71 procapsid (yellow; PDB ID 4GMP), a murine Fab molecule (dark blue; PDB ID 3GK8), and a murine Fab variable domain (light blue) were fitted into the cryo-EM density map (gray mesh). The fitted variable domain superimposes onto the fitted Fab with an RMSD of 1.88 Å. The pseudoatomic model shows that the disordered GH loop of VP1 (magenta) is at the interface between the procapsid and Fab.