University of Illinois, Urbana-Champaign
Biological Contrast Agents for Analyte-Specific Magnetic Resonance Imaging
Research in the Olshansky lab centers on mimicking the ways biological systems use conformational changes to control metal ion reactivity. We synthesize ligands and prepare artificial metalloproteins in which conformational changes are triggered to produce distinct changes in function at the metal ions within. Our focus is understanding and exploiting this interplay. It is a central paradigm in metalloenzyme reactivity yet remains largely absent from designed synthetic and artificial systems.
Metal ions are responsible for catalyzing fundamental chemical transformations central to metabolic, catabolic, and biosynthetic processes in all organisms. However, left unchecked, their reactivity is extremely difficult to control. As a result, nearly all metalloprotein reactivity is gated by some form of conformational change. Unfortunately, the link between conformational control and control over metal ion reactivity is extremely difficult to study in natural systems, where often a single point mutation or environmental change could have multiple effects that cannot be disentangled. By creating simplified models that still encapsulate the complex structural dynamics at play in natural systems, we are able to tune and then directly probe the link between conformational control and control over metal ion reactivity. Through these studies we aim to define kinetic, thermodynamic, and mechanistic parameters underpinning conformational control in Nature’s redox machines.
The systems we develop represent novel stimulus-responsive constructs in which triggered conformational changes result in pronounced changes in reactivity. Thus, beyond our inquiries into basic science questions, we are able to leverage these features in an array of applications. Current areas of focus are on the development of biomimetic systems for solar energy conversion, biocompatible agents for analyte sensing in vivo, and the development of catalysts in which cooperativity between proton transfer, electron transfer, and conformational changes result in efficiencies not yet possible by other avenues. We hypothesize that mechanical motion represents an efficient means with which to interconvert different forms of energy. Our research aims to test this hypothesis, and then capitalize on the results.