2 research outputs found
Projector-Based Embedding Eliminates Density Functional Dependence for QM/MM Calculations of Reactions in Enzymes and Solution
Combined
quantum mechanics/molecular mechanics (QM/MM) methods
are increasingly widely utilized in studies of reactions in enzymes
and other large systems. Here, we apply a range of QM/MM methods to
investigate the Claisen rearrangement of chorismate to prephenate,
in solution, and in the enzyme chorismate mutase. Using projector-based
embedding in a QM/MM framework, we apply treatments up to the CCSDÂ(T)
level. We test a range of density functional QM/MM methods and QM
region sizes. The results show that the calculated reaction energetics
are significantly more sensitive to the choice of density functional
than they are to the size of the QM region in these systems. Projector-based
embedding of a wave function method in DFT reduced the 13 kcal/mol
spread in barrier heights calculated at the DFT/MM level to a spread
of just 0.3 kcal/mol, essentially eliminating dependence on the functional.
Projector-based embedding of correlated ab initio methods provides a practical method for achieving high accuracy
for energy profiles derived from DFT and DFT/MM calculations for reactions
in condensed phases
Analysis of key effects in enzyme-catalysed reactions by QM/MM simulations
EThOS - Electronic Theses Online ServiceGBUnited Kingdo