Solvents for Polarizable Biomolecular Solutes

A continuum solvent replaces explicit atomic details with a bulk, mean-field response. It is possible to demonstrate from statistical mechanics that an implicit solvent potential of mean force (PMF) exists, which preserves exactly the solute thermodynamic properties obtained from explicit solvent. It is possible to formulate a perfect implicit solvent in principle, but in practice approximations are necessary to achieve efficiency. This remains an active area of research.An implicit solvent PMF can be formulated via a thermodynamic cycle that discharges the solute in vapor, grows the uncharged (apolar) solute into a solvent W pgi fX), and finally recharges the solute within a continuum dielectric Weiec(X) 

The continuum electrostatic energy, including mobile electrolytes, can be described by either the nonlinear Poisson-Boltzmann equation (NPBE) or the simplified linearized Poisson-Boltzmann equation (LPBE) 

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