Fig. 4. Hydrogen bonding in the S1 pocket. Example configurations of (A) HD41-HE164 characteristic of robust S1 pocket interactions, (B) HE41-HD164-HP172 illustrating the rupture of the Ser1′–Glu166 interaction and loss of the His163–Tyr161 hydrogen bond, and (C) HE41-HP163-HD164 depicting the loss of the Tyr161 hydrogen bond donation and the His172–Glu166 interaction.
