Scaling in Solvation: Implicit Solvent vs. Explicit Solvent

Professor Ray Luo
Department of Molecular Biology and Biochemistry
University of California, Irvine


Implicit solvents have become increasingly popular in biomolecular simulations. However their wide applications have revealed many limitations, such as improper balance of secondary structures, over population of salt-bridge interactions, and stability of proteins in molecular dynamics. These well-known limitations of implicit solvents show that more developments are still needed to fully establish the applications of implicit solvents in biomolecular simulations. We have initiated efforts to quantitatively and rigorously address how well implicit solvents can approximate explicit solvents. We have studied whether implicit solvents break down when scaling from small organic molecules to typical-sized biomacromolecules. We have analyzed implicit solvents in the context of molecular dynamics simulations on simple systems such as dipeptides and peptides where conformational sampling is less challenging. We have found overall a good agreement between implicit and explicit solvents when consistent calibration and testing is performed. We have also noticed limitations in implicit solvents that require further development.