For OPH:I255S, the interactions established in and near the binding site are similar to those identified during the simulations of the WT complex. One stable hydrogen bond was induced by the mutation and formed between the mutated residue Ser 255 and Ser 299 (Figure ). To our knowledge, S299 is not directly involved in the binding site activity, suggesting that the S255 mutation would not affect the stability of the active site and the catclytic activity.