Mixed QM/MM

Large systems, such as enzymes or dendrimers, should be treated with tools that are appropriate for the questions one is trying to ask, or the experimental data that has been measured. For instance, processes that do not involve bond breaking or forming, such as conformational transitions, can be safely treated with a version of classical mechanics, without need to resort to quantum mechanics. If, however, one is looking for reaction mechanisms, quantum mechanics will be essential. How then, do we treat systems such an enzymes, where we are after reaction mechanisms but the system is too large for quantum mechanics? We use a family of methods known in the literature as mixed Quantum Mechanics/Molecular mechanics (QM/MM for short).

Although a vast number of advanced computational techniques are developed annually, for them to be utilized, they must be implemented. Our group implements such methods into a software suite (Amber) thereby making these techniques available to scientists worldwide.