Quantum chemical calculations on structural models of the catalytic site of chymotrypsin: Comparison of calculated results with experimental data from NMR spectroscopy

Hybrid density functional quantum mechanical calculations were used to study the strength of the hydrogen bond between His(super 57)N(super delta1) and Asp(super 102)O(super delta1) in chymotrypsin and how it changes along the reaction coordinate. The results confirm the hypothesis that the strengthened hydrogen bond plays an important role in lowering the energy of the transition state and hence, in the catalytic efficiency of the enzyme.