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. 2022 Aug 4;17(9):2425–2436. doi: 10.1021/acschembio.2c00040

Figure 4.

Figure 4

Substitution I375F identified in the HA of resistant H1N1pdm09 impedes peptide binding to H1. H1N1pdm09 was passaged five times on MDCKII cells in the presence or absence of the S5 peptide. (a) Virus passaged in the presence of S5 is no longer sensitive to inhibition by the peptides in a luciferase assay for viral replication. Data are shown as mean ± SD (n = 3). (b) Substitutions identified in the HA of the S5-passaged H1N1 virus (blue) and the control-passaged virus (green, H3 numbering). One substitution in the resistant virus, I375F, is located in the peptide-binding site as determined by HDX (red). (c) Immunofluorescence staining of cells expressing wild-type H1, or H1 with single substitutions in the stem region found in the resistant virus (I375F or I463V). HA is stained with pAb αH1 (green) and the biotinylated S5 peptide (red). Nuclei are labeled with DAPI (blue).