The magnitude of field fluctuations is affected by the sensitivity of the force field electrostatic model to small structural changes. The AMOEBA field distributions were therefore compared with those of the Amber ff14SB and Charmm C36m additive models, with a TIP3P water model in both cases. For each of the additive force fields, the electric fields at the substrate peptide C and N atoms were recalculated for each trajectory frame of the AMOEBA structural ensemble from the first replicate.