A. V. Rogov, B. L. Grigorenko, A. V. Bochenkova, A. A. Granovskii, A. V. Nemukhin The role of magnesium in the hydrolysis reaction of triphosphates in aqueous solution: quantum mechanical – molecular mechanical simulations Abstract The mechanism of the hydrolysis reaction of the unprotonated methyl triphosphate (MTP) ester resulting in the methyl diphosphate (MDP) and inorganic phosphate (Pi) in water clusters in presence and absence of magnesium cation has been modeled. The effective fragment potential based quantum mechanical – molecular mechanical (QM/MM) approach has been applied in the simulations. Density functional theory (B3LYP) approximation has been used for calculations of energies and energy derivatives in the quantum subsystem (MTP, reacting water molecules and Mg2+) while water-water interactions have been described with the TIP3P model potential. It is shown that the minimum energy path for the reaction MTP + H2O ® MDP + Pi is consistent with the two-step dissociative-type process in the absence of Mg2+, and the single-step transformation in the presence of Mg2+.
Copyright (C) Chemistry Dept., Moscow State University, 2002 |
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