A positive value of %SASA meant the residue became more exposed when the particle assembly shifts from virion (3 copies of E dimers per icosahedral asymmetric unit) to VLP (1 copy of E dimers per icosahedral asymmetric unit). The black dash line indicated the Δ%SASA >0.2, which was defined as highly exposed residues in VLP comparing to virion. The high positive values which were focused in the peptide regions such as the fusion loop peptide (including amino acid (aa) residues ranging from 100 to 110), aa 169–170 at domain I, aa 222–226, aa 239 and aa 251–262 at domain II as well as A strand of domain III (aa 300–308), the cd loop of domain III (aa 342–348) and G strand (aa 386–388) around the 5-fold openings. The residues interacting with MAb 1A1D-230, including residues 305–312, 352, 364, 388 and 390; the residues interacting with MAb 2D2231, including residues 67–72, 99, 101–104, 113, 177–180, 225–227, 247, 328, 384–386 (Heavy chain); 148–149, 153–155, 291–293, 295, 298, 299, 307, 309–310, 325, 327, 362–363 (light chain) and the residues interacting with human MAb EDE antibodies (Rodenhuis-Zybert et al., 2011), including aa residues 67–74, 97–106, 148–159, 246–249 and 307–314 were indicated. (A, right) The high positive peaks (Δ%SASA >0.2), low positive peaks (Δ%SASA between 0 and 0.2) and negative peaks (Δ%SASA <0) in the plot were colored by dark red, deem red and grey in the E dimer surface rendering. The groove located within E-dimer interface was outlined. (B) The highly exposed residues (Δ%SASA >0.2) which were colored by dark red were shown in the surface rendered E-dimer. The residues in E interacting with MAb 1A1D-2, 2D22 and EDE were in cyan spheres showing that they were highly exposed on the m2DVLP surface. Importantly, the binding footprints of the three antibodies were highly overlapping with footprint of highly exposed residues in m2DVLP, and formed a neutralization sensitive patch on m2DVLPs. The areas of the interacting epitopes are circled by black lines. (C) The E protein forming the rafts in virion were shown in the left panel where the three individual E proteins in the asymmetric unit are labeled A, B, and C of the E proteins, in the neighboring asymmetric unit are labeled A’, B’, and C’. The icosahedral 2-fold E protein dimers (B and B’) in m2DVLP have moved apart from each other causing the groove (right). The aa 101 which was responsible for DM25-3 antibody binding were shown in orange spheres.