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Lisa Olshansky – University of Illinois

Host: Carsten Krebs (865-6089)

"Emergent Properties from Dynamicity: Investigating Conformational Control in Biomimetic Inorganic Systems"

Abstract:

From the reduction of dinitrogen to the oxidation of water, the chemical transformations catalyzed by metalloenzymes underpin global geo- and biochemical cycles. These reactions represent some of the most kinetically and thermodynamically challenging processes known. Interestingly, rate-limiting conformational changes precede catalysis in many metalloenzymes. The pervasiveness of this mechanistic pattern suggests that conformational gating may play an important role in mediating challenging chemical transformations in an energy-efficient manner. However, these enzymes are extremely complex, rendering direct examination of their conformational gating steps a tremendous challenge. Instead, we have taken the unique approach of preparing model systems in which macroscopic changes in the molecular structure of a ligand or protein host give rise to subatomic changes in the electronic structure of a bound metal ion. These systems include both conformationally dynamic coordination complexes and conformationally switchable artificial metalloproteins. In both cases, exciting new properties have emerged from the structural dynamicity at play. Ultimately, our work with these systems aims to define and quantify the kinetic and thermodynamic consequences of conformational gating mechanisms. Additionally, the systems under development are molecular switches and can also be exploited in applications ranging from solar energy conversion, to biomedical imaging, to green methods in chemical catalysis.