FIG. 4.

Distribution of conserved and variable residues on the surface of mature DEN-1 virus. (A) Backbone trace of the atomic model of the DEN-1 outer protein shell based on the 9.5-Å-resolution electron microscopy reconstruction of DEN-2 (25). Two E subunits are outlined in gray. (B) Seventy-five residues are strictly conserved in the West Nile, TBE, Japanese encephalitis, yellow fever, and dengue viruses. Few of these residues are visible on the viral surface (shown as space fillers, with the same coloring scheme as in previous figures). The largest surface-exposed cluster (labeled with a black arrow) consists of 9 residues in the region of the fusion loop. (C) Same view as in panel B, with residues shown in color only if they are unique to DEN-1. Of the 36 such DEN-1-specific residues, 7 cluster in a ridge on the central surface of domain II (yellow), 11 are distributed across the surface of domain I (red), and 8 are exposed on the surface of domain III (blue).