Structural Basis for the Immunogenicity of the C-Terminus of VP1 of Echovirus 3 Revealed by the Binding of a Neutralizing Antibody

Figures

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  Figure 1. (A). Surface representation of the E3 F-, A-, and E-particles in complex with 6D10 and their corresponding central sections viewed along the twofold axes, respectively. The surface of the virus is colored by the radius from blue to red, and the Fab of the 6D10 is colored in light purple. (B). The top view of the 6D10 binding on a viral pentamer. The color scheme is shown at the bottom of the panel. (C). The binding affinity of 6D10 IgG with E3 was estimated by surface plasmon resonance (SPR). (D). Neutralization curve of the interaction of E3 with 6D10 measured by the plaque-reduction neutralization test (PRNT).

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  Figure 2. (A). Side view of the binding model of the E3–6D10 complex. The E3 is represented by the surface, and 6D10 is shown as a cartoon. The color scheme is the same as in panel B. The dotted squares indicate the region in panel F. (B). Superimposition of the C-terminus of VP1 in the E-upright and E-sideling particles. The C-terminus of VP1 is highlighted in cartoon, and the surface indicates VP3. (C,D). The upper panels (panel G) represent the VP1 C-terminal (shown as dark blue sticks) embedded into the hydrophobic pocket of the 6D10 (colorful surface). The lower panels (panel H) display the detailed interactions between the E3 particles and 6D10 corresponding to panel G. The key residues are shown as sticks. Hydrogen bonds are marked as yellow dashes. The color scheme is the same as in panel B.