Figure 4.

The topology and evolutionary conservation of the BDBV NP^Ct surface involved in the interaction with MJ20. (a) BDBV NP^Ct is represented schematically by a green ribbon, with the solvent-accessible surface (within the complex with MJ20) shown in a semitransparent manner. The N- and C-termini are marked for clarity. The MJ20-binding concave crevice is located centrally between the N-terminal α-helix hairpin and the C-terminal lobe of the protein. The residues forming the largest contacts with MJ20^HC are represented by blue spheres, while eight conserved residues targeted by alanine scanning (see text) are shown as orange sticks. (b) The same view of the BDBV NP^Ct surface, showing amino-acid conservation among the five strains of the virus. The MJ20 interface (delineated by dashed lines) is shown again in the inset, with a stick representation of the critical seven amino acids from the CDR3^HC loop of MJ20.