Simulated Solute Tempering in Fully Polarizable Hybrid QM/MM Molecular Dynamics Simulations.

We successfully apply a solute tempering approach, which substantially reduces the large number of temperature rungs required in conventional tempering methods by solvent charge scaling, to hybrid molecular dynamics simulations combining quantum mechanics with molecular mechanics (QM/MM). Specifically, we integrate a combination of density functional theory (DFT) and polarizable MM (PMM) force fields into the simulated solute tempering (SST) concept. We show that the required DFT/PMM-SST weight parameters can be obtained from inexpensive calculations and that for alanine dipeptide (DFT) in PMM water three rungs suffice to cover the temperature range from 300 to 550 K.