Fig. 2: PN-SIA28 blocks proteolytic activation and inhibits low pH-induced conformational change in HA. | Nature Communications

Fig. 2: PN-SIA28 blocks proteolytic activation and inhibits low pH-induced conformational change in HA.

From: Structural basis for a human broadly neutralizing influenza A hemagglutinin stem-specific antibody including H17/18 subtypes

Fig. 2

a SDS–polyacrylamide gel electrophoresis results of uncleaved (HA0), recombinant-soluble H1, H5, H3, or H14 HA after digestion with trypsin at pH 8.0 for 0, 10, 20, 40, 60, 90, or 120 min. Digest reactions of HA with or without PN-SIA28 were stopped at several time points by adding a loading buffer containing SDS and dithiothreitol. H10 and trypsin-treated PN-SIA28 served as the experimental control and negative control, respectively. Data represent a representative experiment from two independent experiments. b, SDS–polyacrylamide gel electrophoresis results of the protease-susceptibility assay for HAs. Exposure of HA to low pH converts the HA to the protease-susceptible, post-fusion state (lane 3). Treatment of HA with PN-SIA28 before low-pH treatment blocks the pH-induced conformational change, retaining HAs (H1, H5, H3, H14, H17, and H18) in the protease-resistant, prefusion state (lane 7). Treatment of HA with CR9114 and FI6v3 before low-pH treatment blocks the pH-induced conformational change, retaining HAs (H17 and H18) in the protease-resistant, prefusion state (lane 7). In contrast, the pH-induced conformational change of H17 and H18 could not be blocked by treatment of HA with 39.29 or MEDI8852 prior to low-pH treatment. Data represent a representative experiment from two independent experiments. Source data are provided as a Source Data file.

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