Computational chemistry has become an indispensable tool in modern chemical and biological research, providing atomic-level insight into molecular structure, reactivity, and function. In this presentation, I illustrated how quantum mechanical (QM), molecular mechanical (MM), and hybrid QM/MM methods were applied to investigate complex biological systems and to address practical problems in biochemistry and drug discovery. Several representative case studies from my own work were discussed, including the origin of enantioselectivity in enzymes, detailed enzymatic reaction mechanisms, redox potential calculations of iron–sulfur proteins, and structure-based drug design. These examples demonstrated how computational methods could not only rationalize experimental observations but also guide enzyme engineering and drug discovery through predictive, mechanism-based modeling. The presentation highlighted the role of multiscale modeling in bridging electronic structure theory and biomolecular simulations, and emphasized the increasing impact of computational chemistry as a central component of modern molecular life sciences.
