The role of intermolecular charge transfer (CT) in ion conduction through channels is largely unexplored. Charge transfer, the movement of small amounts of electron density (< 0.1 e) in intermolecular interactions, is a common feature of ion-ligand interactions. The polarizability of ligands also has an important role in ion-ligand energetics. However, polarizability and CT are neglected in current molecular mechanics (MM) simulations of ion channels. Herein, a fluctuating charge (FQ) force field is used to study the role of polarizability in potassium conduction in KcsA. The method for including CT in MM simulations developed by our group predicts non-integer ionic charges and non-neutral water molecules, consistent with ab initio molecular dynamics simulations. This method is expanded to include CT between the peptide backbone and ions. The role of CT in KcsA ion conduction is explored using this CT force field.

Charge transfer and polarizability in the KcsA potassium channel via molecular mechanics

247th National Meeting (2014)

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