CaSTL Seminar with Anastassia Alexandrova

While only a handful of amino acids in the binding sites of an enzyme participate in catalysis, the large protein macromolecule also is thought to have a function: it provides a highly special electric field in the binding site that is preorganized to stabilize the transition state of the catalyzed reaction. We will present two models to capture this effect in computational modeling, and show how it can help explaining functionality of natural enzyme variants, and also what role electrostatic preorganization plays in directed evolution of artificial enzymes. One new model is the simple and classical. The other one, rigorous and involved, is our adaptation of the quantum theory of atoms in molecules. We will show that preoganization plays a role in positioning of critical points (such as bond critical points) in the charge density, and how that reflects in the reactivity. We will further show that the effect of electrostatic preorganization is more local than one might suspect.