Figure 1.
The homology model of Hangzhou-H7 built using the 4DJ8.PDB H7N7 crystal structure as a template. The zoomed region shows the receptor-binding pocket. Residues that form the receptor-binding pocket are highlighted in green and those mutations that determine receptor specificity are highlighted in red.
Figure 2.
Binding affinity of Hangzhou-H7 and H7N7 for human and avian receptors.
Hangzhou-H7 and the closely related H7N7 virus (A/Netherlands/219/2003) were docked to human and avian sialic acid receptors and affinities calculated. (A) The predicted Hangzhou-H7 model receptor affinities are shown by the black bars and the A/Netherlands/219/2003 affinities by the white bars. (B) The highest affinity docking conformation of Hangzhou-H7 on the human (brown), and avian (purple), receptors. HA mutations that influence the receptor binding specificity are highlighted in red and other residues that interact with the receptor in yellow. Residues that form the receptor-binding pocket are highlighted in green.
Figure 3.
Hangzhou-H7 neutralizing antibody binding.
(A) The structures of neutralizing antibodies are shown either binding to the Hangzhou-H7 (shown in blue) globular head region (left figure) or stalk region (right figure). Different colours represent different antibodies. HA residues interacting with stalk-binding neutralizing antibodies are shown in the right hand figure highlighted in yellow. (B) HA-neutralizing antibodies binding the head or stalk regions were docked to the predicted Hangzhou-H7 structure and binding energies were calculated and presented as an absolute value. PDB IDs of antibodies against H1 are 3LZF, 3SM5, 4M5Z, 3GBN, 3ZTN, PDB IDs for H3 are 1EO8, 1KEN, 1QFU, 2VIR, 4FQR, 3SDY, 4NM8, H5 PDB IDs are 3FKU and 3GBM and H7 ID is 4FQV.
Figure 4.
Multiple sequence alignment of HA1 of crystalized antibody-HA complexes of H1, H3, A/Netherlands/219/2003(H7N7) (4DJ8) and WHO H7N9 vaccine candidates (NIBRG-63 and NIBRG-109).
Residues on HA1 which are within 4 Å distance from the docking site of the neutralizing antibody are highlighted in yellow on the respective HA sequence available on the crystalized antibody-HA complex. Linear antigenic epitopes, as predicted by using Kolaskar and Tongaonkar antigenicity scale on Hangzhou/H7 are highlighted in cyan and homologous regions to those epitopes on A/Netherlands/219/2003(H7N7) and WHO vaccine candidates (NIBRG-63 and NIBRG-109) are highlighted in blue.