Assistant Professor
Building theories of redox enzyme catalysis, especially electron bifurcation
Enzymes can direct and coordinate electron transfer reactions to accomplish difficult redox transformations. Of particular interest is electron bifurcating enzymes, which can push electrons thermodynamically “uphill" to lower potential, harnessing energy released by other electrons flowing “downhill”. So far, this process has not been achieved or even observed in the absence of natural enzymes. By studying the process of electron tunneling through proteins, the structure and conformational dynamics, and kinetics of electron flows through redox cofactors, we aim to build a detailed understanding of electron bifurcating and other processes in enzymes. These lessons can then be translated into synthetic contexts (see below).
Electrocatalysis and electron/energy transfer at interfaces
Reactions at interfaces are important because they allow us to harness two phases of matter simultaneously. For example, at semiconductor-electrolyte interfaces allow us to use the chemistry of redox reagents with the reactivity and charge transport properties of electrons and holes inside the semiconductor. Currently, we are developing ideas about how to mimic electron bifurcation reactions using tailored semiconductor electrodes. If these ideas are successfully implemented by experimental groups, they will become one of the few bioinspired electronic devices invented to date (obviously photovoltaic cells are a predecessor). Beyond this, interfaces can shed light on light-matter interactions, proton-coupled electron transfer reactions, and the properties of catalytic sites.
Modeling the ecology of microbial catabolism and biogeochemical cycling
Microbial communities in nature often form nearly perfect circular economies. Starting with mostly small organic and inorganic compounds, microbes construct elaborate biological structures before breaking them down again for recycling. Often, these biochemical processes work alongside naturally occurring geochemical processes too. Together, these complex networks of chemical reactions are interesting because they are not traditional chemical reactors. Microbial communities do not have well-defined catalyst content, nor do they have operating lifetimes — they survive indefinitely. Furthermore, microbes must compete (and coordinate) for survival and maintain genomic flexibility to respond to environmental perturbations and opportunistic competitors. By building models at the crossroads of ecology and molecular biology, we hope to gain a better understanding of nature’s circular economy and extract lessons for chemical processing and bioremediation.
