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Calculation of solvation free energy utilizing a constrained QM/MM approach combined with a theory of solutions.
J Chem Phys. 2019 Mar 21; 150(11):114109.JC

Abstract

In an extended QM/MM (quantum mechanical/molecular mechanical) description of a solution, the solvent molecules surrounding the solute are incorporated into the QM region besides the solute. In a recent development, we introduced a simple and efficient method, referred to as boundary constraint with correction (BCC), to prevent the diffusion of the QM solvent into the bulk. The major purpose of the present work is to develop a method to compute the solvation free energy of a QM solute in an extended QM/MM simulation by means of the BCC method. The strategy of our development is to utilize the QM/MM-ER method which combines the QM/MM simulation and the theory of solutions termed energy representation (ER) to expedite the free energy calculation. A theory is, then, formulated to couple QM/MM-ER and the BCC method on the basis of the statistical mechanics. A notable feature of our method is that the effect of the constraint potentials on the free energy completely vanishes when the force field of the QM solvent coincides with that of the MM solvent. The method is applied to the calculations of the solvation free energies of a water molecule and a hydronium ion in water solutions. It turns out that the present method can offer a significant improvement in describing the free energy Δν of the hydronium ion, in particular, as compared with the conventional QM/MM approach. Explicitly, Δν is obtained as -98.0 kcal/mol showing a good agreement with an experimental value of -103.5 kcal/mol, while -86.1 kcal/mol by the conventional method.

Authors+Show Affiliations

Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan.Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan.Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

30902001

Citation

Takahashi, Hideaki, et al. "Calculation of Solvation Free Energy Utilizing a Constrained QM/MM Approach Combined With a Theory of Solutions." The Journal of Chemical Physics, vol. 150, no. 11, 2019, p. 114109.
Takahashi H, Kambe H, Morita A. Calculation of solvation free energy utilizing a constrained QM/MM approach combined with a theory of solutions. J Chem Phys. 2019;150(11):114109.
Takahashi, H., Kambe, H., & Morita, A. (2019). Calculation of solvation free energy utilizing a constrained QM/MM approach combined with a theory of solutions. The Journal of Chemical Physics, 150(11), 114109. https://doi.org/10.1063/1.5089199
Takahashi H, Kambe H, Morita A. Calculation of Solvation Free Energy Utilizing a Constrained QM/MM Approach Combined With a Theory of Solutions. J Chem Phys. 2019 Mar 21;150(11):114109. PubMed PMID: 30902001.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Calculation of solvation free energy utilizing a constrained QM/MM approach combined with a theory of solutions. AU - Takahashi,Hideaki, AU - Kambe,Hiroyuki, AU - Morita,Akihiro, PY - 2019/3/24/entrez PY - 2019/3/25/pubmed PY - 2019/3/25/medline SP - 114109 EP - 114109 JF - The Journal of chemical physics JO - J Chem Phys VL - 150 IS - 11 N2 - In an extended QM/MM (quantum mechanical/molecular mechanical) description of a solution, the solvent molecules surrounding the solute are incorporated into the QM region besides the solute. In a recent development, we introduced a simple and efficient method, referred to as boundary constraint with correction (BCC), to prevent the diffusion of the QM solvent into the bulk. The major purpose of the present work is to develop a method to compute the solvation free energy of a QM solute in an extended QM/MM simulation by means of the BCC method. The strategy of our development is to utilize the QM/MM-ER method which combines the QM/MM simulation and the theory of solutions termed energy representation (ER) to expedite the free energy calculation. A theory is, then, formulated to couple QM/MM-ER and the BCC method on the basis of the statistical mechanics. A notable feature of our method is that the effect of the constraint potentials on the free energy completely vanishes when the force field of the QM solvent coincides with that of the MM solvent. The method is applied to the calculations of the solvation free energies of a water molecule and a hydronium ion in water solutions. It turns out that the present method can offer a significant improvement in describing the free energy Δν of the hydronium ion, in particular, as compared with the conventional QM/MM approach. Explicitly, Δν is obtained as -98.0 kcal/mol showing a good agreement with an experimental value of -103.5 kcal/mol, while -86.1 kcal/mol by the conventional method. SN - 1089-7690 UR - https://www.unboundmedicine.com/medline/citation/30902001/Calculation_of_solvation_free_energy_utilizing_a_constrained_QM/MM_approach_combined_with_a_theory_of_solutions L2 - https://dx.doi.org/10.1063/1.5089199 DB - PRIME DP - Unbound Medicine ER -
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