Amino acid tautomerization reactions in aqueous solution via concerted and assisted mechanisms using free energy curves from MD simulation.
A theoretical study is described of chemical reactions in solution by means of molecular dynamics simulations, with solute-solvent interaction potentials derived from AMBER van der Waals parameters and QM/MM electrostatic charges in solution. The solvent is used as the reaction coordinate, and the free energy curves to calculate the properties related to the reaction mechanism. The proposed scheme is applied to the tautomerization process in aqueous solution for some amino acids H(2)NCHR-COOH (with R = H being glycine, R = CH(3) alanine, R = CH(2)OH serine, and R = CH(2)COOH aspartic acid), focusing on the role of the solvent in the reaction (assisted versus unassisted mechanisms) and on the effect of the hydrophilic/hydrophobic character of the radical R on the activation and reaction energies.
Departamento de Ingeniería Química y Química Física, Universidad de Extremadura, 06071-Badajoz, Spain. santi@unex.es
Santiago
S
Tolosa
Antonio
A
Hidalgo
Jorge A
JA
Sansón
D000596:Amino Acids / Q000737:chemistry*; D007536:Isomerism; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D012996:Solutions; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D000596:Amino Acids; D012996:Solutions; D014867:Water