Incorporation of solvation effects into the fragment molecular orbital calculations with the Poisson–Boltzmann equation

We developed FMO-PB method, which incorporates solvation effects into the Fragment Molecular Orbital calculation with the Poisson–Boltzmann equation. This method retains good accuracy in energy calculations with reduced computational time. We calculated the solvation free energies for polyalanines, Alpha-1 peptide, tryptophan cage, and complex of estrogen receptor and 17β-estradiol to show the applicability of this method for practical systems. From the calculated results, it has been confirmed that the FMO-PB method is useful for large biomolecules in solution. We also discussed the electric charges which are used in solving the Poisson–Boltzmann equation.