PNNL

Abstract

The free energy profile for electron flow through the bacterial deca-heme cytochrome MtrF has been computed using thermodynamic integration and classical molecular dynamics. The extensive calculations on two versions of the structure help validate the method and results, because differences in the profiles can be related to differences in the charged amino acids local to specific heme groups. First estimates of reorganization free energies ? yield a range consistent with expectations for partially solvent exposed cofactors, and reveal an activation energy range surmountable for electron flow. Future work will aim at increasing the accuracy of ? with polarizable force field dynamics and quantum chemical energy gap calculations, as well as quantum chemical computation of electronic coupling matrix elements.