Title: Living on Nitrogen
Abstract: Some of the most abundant microorganisms on Earth do not live as we do––rather than using carbon-based fuels, they instead rely on the oxidation of ammonia to furnish reducing equivalents for life. These ammonia oxidizing bacteria and archaea (AOB and AOA)––Nature's inorganic chemists––pervade every ecosystem, where they drive key reactions of the nitrogen cycle collectively referred to as “nitrification.” Constantly increasing use of nitrogen-based fertilizers by humans has been a boon to AOB and AOA, which excrete waste products that pollute drinking water and lead to ecological imbalances such as algae blooms. Despite the global impact of nitrification, its underlying biochemistry and structural biology remains ripe for inquiry. This lecture will describe studies by the Lancaster Group to elucidate metallocofactor-catalyzed transformations underpinning the primary metabolisms used by AOB and AOA to oxidize ammonia and subsequent intermediates towards generation of their common stoichiometric product, nitrite. Key topics will include the identification of nitric oxide as an obligate intermediate of bacterial nitrification, control of selectivity in hydroxylamine oxidation, and mechanisms of generation of nitrous oxide as a common waste product by both AOA and AOB.
Biography: Kyle Lancaster, a native of Orange County, CA, received his B.A. in Molecular Biology from Pomona College in 2005. He next earned a Ph.D. in Chemistry at Caltech in 2010 after studying artificial biological copper electron transfer proteins with Harry Gray. He completed a brief postdoc at Cornell University with Serena DeBeer during which he helped to develop X-ray emission spectroscopy as a tool to study metalloproteins. He has since remained at Cornell, where he runs an interdisciplinary research program merging synthesis, biochemistry, structural biology, and spectroscopy. Current research foci are understudied pathways in the biogeochemical nitrogen cycle and atom transfer reactivity carried out by base metals.
LOCATION:Pfizer Lecture Hall STATUS:CONFIRMED DTSTART:20251112T211500Z DTEND:20251112T224500Z END:VEVENT END:VCALENDAR