 Substitution with smaller valine (Ile826Val mutation) could increase the space for EHNA and cause the loss of hydrogen binding with residues in the upper binding pocket, while improving hydrogen binding within the lower binding pocket.This shift of interactions could destabilize binding of the adenine ring of EHNA, which could be the reason for higher IC50 value.No models are available for the other inhibitors than EHNA, which align in the active site.