Figure 4.

The epitope bound by Fab 1F4.

1. Densities of Fab 1F4 on E proteins in two icosahedral asymmetric units. Fab 1F4 molecules bind to molecules A and B in each asymmetric unit.
2. Open-book representation of Fab 1F4 binding to E protein. The E protein DI, DII and DIII are colored in red, yellow and blue (top), respectively, whereas the Fab 1F4 heavy and light chains are colored in green and cyan (bottom), respectively. The epitope bound by Fab 1F4 is located on the DI and DI-II hinge regions (top). The epitope on E protein bound by the heavy and light chain are colored in green and cyan, respectively (top). Also the epitope on DI that interacted with both heavy and light chains are colored in purple (top). The paratope on heavy and light chain (bottom) are colored in its corresponding interacting residues on the DI (red) and DII (yellow) E protein, paratope binding to both DI and II on the E protein is colored in pink.
3. Ribbon representation of the HMAb 1F4 epitope on E protein (top) and also sequence alignment of the epitope region between all dengue virus serotypes (bottom). The β-strand and loop of the epitope are colored in orange and black, respectively (top). In the bottom panel, the secondary structures are shown above the amino acid sequence. The amino acid residues that interact with Fab 1F4 are highlighted in the same coloring scheme as in (B). The amino acid sequences are derived from DENV1 strain PVP159, DENV2 strain S16803, DENV3 strain Thailand 1995 and DENV4 strain Dominica 1981.