Figure 4: Emergence of predicted N-linked glycans (PNGs) across human H3 viruses and evasion by F045–092.

(a) Stacked graph showing the normalized percentage of strains that contain an additional PNG on HA1 at each indicated position. Seven PNGs have been incorporated in the HA since 1968 in addition to the five absolutely conserved PNGs in H3 strains (HA1 Asn22, Asn38, Asn165, Asn285; HA2 Asn154), except for the PNG at Asn81 (1968–1977). (b) F045–092 evades the glycan at Asn133 proximal to the receptor-binding site in the Vic2011/H3 complex. The glycan is shown as spheres, with carbon in yellow, oxygen in red and nitrogen in blue. No density corresponding to the PNG at Asn144 (shown as sticks) was observed.