A new charge model, called Charge Model 4 (CM4), and a new continuum solvent model, called Solvation Model 6 (SM6), are presented. Using a database of aqueous solvation free energies for 273 neutrals, 112 ions, and 31 ion-water clusters, parameter sets for the mPW0 hybrid density functional of Adamo and Barone (Adamo, C.; Barone, V. J. Chem. Phys. 1998, 108, 664-675) were optimized for use with...

In an implicit-solvent description of molecular solvation, the electrostatic free energy is given through the electrostatic potential. This potential solves a boundary-value problem of the Poisson-Boltzmann equation in which the dielectric coefficient changes across the solute-solvent interface-the dielectric boundary. The dielectric boundary force acting on such a boundary is the negative firs...

The solvation energy and entropy at infinite dilution consist of a solute-solvent term and a solvent reorganization term representing the contributions of changes in solvent structure upon solute insertion. In the standard, homogeneous treatment of solutions, changes in solvent structure are expressed through derivatives of the homogeneous pair correlation function, which are very difficult to ...

Statistical thermodynamics provides a powerful theoretical framework for analyzing, understanding and predicting the conformational properties of biomolecules. The central quantity is the potential of mean force or effective energy as a function of conformation, which consists of the intramolecular energy and the solvation free energy. The intramolecular energy can be reasonably described by mo...

The effects of cosolvents on the solubility and hydration of small nonpolar solutes in solution has been investigated using a combination of molecular dynamics simulation and Widom particle insertion calculations. Results were obtained for helium, neon, argon, and methane solutes in solutions of sodium chloride, ammonium sulfate, calcium chloride, ammonium acetate, tetramethylammonium chloride,...

Background: Recent studies have proposed various sources for the origin of cooperativity in simpliied protein folding models. Important contributions to cooperativity that have been discussed include backbone hydrogen bonding, side-chain packing, and hydrophobic interactions. Related work has also focused on what interactions are responsible for making the free energy of the native structure a ...

The highly anisotropic environment of the lipid bilayer membrane imposes significant constraints on the structures and functions of membrane proteins. However, NMR structure calculations typically use a simple repulsive potential that neglects the effects of solvation and electrostatics, because explicit atomic representation of the solvent and lipid molecules is computationally expensive and i...

The solvation energies of salt bridges formed between the terminal carboxyl of the host pentapeptide AcWL- X-LL and the side chains of Arg or Lys in the guest (X) position have been measured. The energies were derived from octanol-to-buffer transfer free energies determined between pH 1 and pH 9. 13C NMR measurements show that the salt bridges form in the octanol phase, but not in the buffer ph...