FIG. 5.
Virulence and tropism determinants in IBDV and IPNV VP2s. Ribbon representations of IBDV (A and B) and IPNV (C and D) VP2 trimers, viewed from the side (perpendicularly to the surface of the virus particle in A and C) and from the top (down the molecular 3-fold axis of VP2 in B and D). The variable loops at the top of domain P are colored according to the insets (PAA′, pink; PBC, cyan; PDE, green; PFG, orange; PHI, red). The side chains of residues implicated in virulence and cell culture adaptation are shown as spheres. These are residues His253, Asn279, and Thr284 for IBDV and residues Pro217 and Thr221 for IPNV.