A simulation of the reaction between glutathion and the hydroxymethyl radical in water by combined quantum and molecular mechanics methodsстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Местоположение издательства:Road Town, United Kingdom
Первая страница:888
Последняя страница:895
Аннотация:Potential energy surface fragments for the reaction between the hydroxymethyl radical (CH2OH)-C-. and glutathion GSH in aqueous clusters were calculated by combined quantum and molecular mechanics methods. The quantum subsystem included the reactive fragment of the cysteine peptide residue and the hydroxymethyl radical. The molecular mechanics subsystem included the rest of GSH represented by a set of effective fragments and water molecules. The geometric parameters of the system were optimized for successively increasing S-H distances in glutathion with the use of the CASSCF/6-31G approximation in the quantum subsystem and the OPLSAA parameters for the molecular mechanics subsystem. The energies at the points corresponding to the reagents, products, and the top of the barrier on the potential energy surface were recalculated using the CASSCF/6-311 + G(d. p) and MP2/6-311 + G(d, p) approximations in the quantum subsystem. According to the calculations, the activation barrier to the reaction (CH2OH)-C-. + GSH in water was 20-22 kJ/mol, which was about 10 kcal/mol higher than for the reference reaction between the hydroxymethyl radical and methylthiol .CH2OH + CH3SH. This increase in the barrier height was largely caused by the influence of glutathion peptide groups rather than the hydration sheath.