FIG 7.

The H16.U4 Fab variable domain fitted into the cryo-EM density. The H16.U4 Fab variable domain with heavy chain (blue) and light chain (orange) is shown fitted with the L1 structural model (red) (PDB ID 3J6R) (18) into the complex map. The unfilled Fab density corresponds to a portion of the constant domain. (A) The zoomed-in image illustrates the interaction between H16.U4 Fab and the C-terminal arm residues C428 to C445 (dark gray). (B) Hexavalent and pentavalent capsomers were indicated to show the directionality of the fitted Fab with the heavy chain following the light chain in a counterclockwise fashion.