Fig. 4: Breadth of binding, specificity and mechanism of fusion inhibition. | npj Viruses

Fig. 4: Breadth of binding, specificity and mechanism of fusion inhibition.

From: VHH antibody loop guides design of a synthetic macrocyclic peptide that potently blocks influenza virus membrane fusion

Fig. 4: Breadth of binding, specificity and mechanism of fusion inhibition.

a Phylogenetic tree representation showing the 18 HA subtypes of influenza A virus [group 1 (light blue) and 2 (orange)] and influenza B (brown). The breadth of binding of the peptide CP1 is marked as (\(\surd\)) and no binding as (\(\times )\). Binding against H8, bat H17 and bat H18 HAs was not tested. b Trypsin susceptibility assay for peptide CP1 with H1/PR8. HA stem-binding antibody CR9114 Fab was used as positive control. Exposure to low pH renders the H1/PR8 HA sensitive to trypsin digestion (lanes 7 vs 8). CR9114 Fab (lanes 9 vs 7) and peptide CP1 (lanes 11 vs 7) protect HA by preventing its conversion to a trypsin-susceptible conformation. c Conformational change inhibition (CCI) assay derived IC50 values for peptides against H1N1 A/Brisbane/59/2007 (H1/Bri) HA. d–f Correlation of CCI, AlphaLISA, and VNA derived IC50 and EC50 respectively, with SPR-derived residence time t1/2. Peptides are represented as LP1 (black), CP1 (yellow), CP4 (magenta), CP8 (green) and CP14 (red) dots.

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