Development and applications of the ABEEM fluctuating charge molecular force field in the ion-containing systems

The microscopic mechanisms of ion hydration and ion selectivity in biomolecular systems are long-standing research topics, in which the difficulty is how to reasonably and accurately describe the ion-water and ion-biomolecule interactions. This paper summarizes the development and applications of the atom-bond electronegativity equalization fluctuating charge force field model, ABEEM/MM, in the investigations of ion hydration, metalloproteins and ion-DNA bases systems. Based on high-level quantum chemistry calculations, the parameters were optimized and the molecular potential functions were constructed and applied to studies of structures, activities, energetics, and thermodynamic and kinetic properties of these ion-containing systems. The results show that the performance of ABEEM/MM is generally better than that of the common force fields, and its accuracy can reach or approach that of the high-level ab initio MP2 method. These studies provide a solid basis for further investigations of ion selectivity in biomolecular systems, the structures and properties of metalloproteins and other related ion-containing systems.