Inorganic Chemistry Seminar: Professor Kyle Lancaster, Cornell University, Sapp Center Lecture Hall, 4:30pm (Host: Ed Solomon)
About the Seminar:
"Mechanistic and Electronic Structural Insights into the Metallobiochemistry of Nitrification"
Nitrification, the oxidation of ammonia to nitrite and nitrate, is a key entry point for fixed nitrogen to return to the atmosphere as dinitrogen. Nitrification is the root of tremendous economic loss in agriculture as well as a major ecological hazard via nitrogenous eutrophication. Molecular details concerning the elementary, multi-electron chemical steps whereby ammonia is oxidized to hydroxylamine and ultimately to nitrite remain elusive. This may be attributable in part to the difficulty associated with accessing sufficient quantities of relevant enzymes for biophysical characterization. Nevertheless, such insights are attractive because they hold the promise of inspiring novel, green chemical methods for difficult bond activations and multi-electron transformations. This talk will describe our investigation of the crucial molecular steps of nitrification revealed through the application of rapid kinetics, spectroscopy, and electronic structure calculations. Key insights include the establishment of a direct link between nitrification and nitrous oxide pollution, the identification of important intermediates in hydroxylamine oxidation by Fe, and a revision of the enzymatic steps involved in hydroxylamine oxidation. The seminar will conclude with reinterpretation of the electronic structure of high-valent copper–oxygen species toward rationalizing competence of these species for challenging E–H bond activations.
About the Speaker:
Professor Kyle Lancaster was born and raised in Orange County, California. Professor Lancaster received a B.A. in Molecular Biology from Pomona College in 2005. During this time he studied enzymes from hyperthermophilic archaea. He was recruited to Caltech by Harry Gray during a visit to Pomona, and joined his laboratory as a Ph.D. student where he studied the influence of second sphere coordination on electron transfer reactivity in copper proteins. During this time he learned several spectroscopic techniques including X-ray spectroscopy, EPR, paramagnetic NMR, and magnetic circular dichroism at a variety of institutions including SSRL, the University of Rosario in Argentina, and the Max-Planck-Institute for Bioinorganic Chemistry (now Chemical Energy Conversion) in Germany. Professor Lancaster moved to Cornell in 2010 to postdoc for Serena DeBeer, during which time he participated in the development of X-ray emission spectroscopy as a probe of coordination environments around first row transition metals. In 2012 he was hired as an assistant professor at Cornell, where he has assembled an interdisciplinary lab that leverages the tools of bioinorganic chemistry (spectroscopy, synthesis, biochemistry) to study biological and synthetic reaction mechanisms.