Atom-bond electronegativity equalization method fused into molecular mechanics(ABEEMσπ/MM)as a fluctuating charge(FQ)force field,was combined with the Generalized Born Solvent Accessible surface area(GB/SA)to calculate the binding free energy of receptor and ligand.The binding free energy is divided into molecular mechanical energy(involving internal energy,van der Waals energy,and Columbic energy),solvation energy and entropic effect.Because the charges on atomic,bond and lone pair's sites are variable in ...