As expected, the positively charged R246 forms a strong electrostatic interaction with D105, while R246I mutation with a neutral charge abolishes that interaction (Figure ). To further demonstrate the stability of the electrostatic interaction, we analyzed the distance between R246 and D105 during the whole simulation process. The distance between R246 and D105 is less than 3.75 Å during 92% of the simulation time, while I246 is more than 6.00 angstroms away from D105 all the time (Figure ), corroborating the idea that this interaction between R246 and D105 is very stable and intense.