Fig 1.

Structural alignment between GII.4 (cyan color) and GI.1 (blue color) VP1 proteins by using the UCSF Chimera software (28). Eight exposed loop regions (highlighted by the dotted red ellipses and marked by loop1–loop8 in the figure) with the most structural variety were chosen for loop grafting to produce the chimeric VLPs. Aiming at these 8 loops, a total of 15 chimeric schemes were designed. These 15 transplanting schemes are illustrated by the inserted sub-figures marked with N1–N15, in which the grafting residues of GII.4 are shown in cyan and the substituted residues on GI.1 are shown in blue, respectively. All the figures were drawn with the UCSF Chimera software (28).