Fig. 6.
Profiling the structural constraints of IAV-HA for glycan binding. The activities of wild-type HK68 and its hemagglutinin-receptor-binding site mutants to infect Sia- or Fuc-edited host cells, were directly compared via host-cell killing. a–d Viability of Sia-edited MDCK cells or control cells upon infection by wild-type HK68 and its HA-RBS mutants, including HK68-MTA (a), HK68-LSS (b) and HK68-QAS (c). d Cell viability at 10−3 viral dilution. e–i Viability of Fuc-edited MDCK cells or control cells upon infection by wild-type HK68 and its HA-RBS mutants. Cell viability at 10−3 virus dilution (h), and at 10−4 virus dilution (i). j Structural alignment of HAs from HK68 and HK68-MTA. A minor shift of 220-loop backbone of HK68-MTA enables formation of a H-bond between C4 hydroxyl of α1-3-linked fucose of sLex and Nε1 of W222 (Fig. 6I), which is not observed between the HK68-WT HA and sLeX. In Fig. 6A-I, the error bars represent the standard deviation of six biological replicates. Source data for figures a–i are provided as a Source Data file