Lisa Olshanksy (U Illinois)

Title: Emergent Properties from Dynamicity: Investigating Conformational Control in Bioinorganic Model Systems

From the reduction of dinitrogen to the oxidation of water, the chemical transformations catalyzed by metalloenzymes underpin global geo- and biochemical cycles and represent some of the most kinetically and thermodynamically challenging processes known. Many metalloenzymes rely on an intricate interplay between protein and metallocofactor structural dynamics to regulate function, suggesting that conformational control may play an important role in mediating challenging chemical transformations under mild conditions. However, the challenge of decoupling conformational from chemical steps in these systems often precludes direct examination of their dynamics. 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. Our work with these systems aims to define and quantify the kinetic and thermodynamic consequences of conformational gating mechanisms. Additionally, these systems are all molecular switches and are also being exploited in the development of novel biosensors, biocatalysts, and molecular rectifiers for solar energy conversion.