About the seminar:
The nitrogenase family of enzymes is responsible for nearly all biological nitrogen fixation and has attracted intense interest for decades due to its ability to reduce N2 to NH3 under ambient conditions. The active site of nitrogenase is a MoFe7S9C cluster, the so-called iron molybdenum cofactor (or FeMoco), which is the site of substrate activation. In recent years, our understanding of the mechanism has advanced substantially, however, many open questions remain as to the specific site of reduction and protonation events during the catalytic cycle. Recently, we have shown that selective Se substitution combined with selenium Kα high-energy resolution fluorescence detected X-ray absorption spectroscopy (Se Kα HERFD XAS) can reveal a more detailed picture of the electronic structure of the active site. In the present study, we utilize a combination of electron paramagnetic resonance (EPR) and Se Kα HERFD XAS, together with extended X-ray absorption fine structure (EXAFS), to understand the mechanism of Se insertion and the nature of early intermediates in the catalytic cycle. In addition, recent spectroelectrochemical studies of a nitrogenase biohybrid system will be presented.
About the speaker:
Serena DeBeer is a Professor and Director at the Max Planck Institute for Chemical Energy Conversion in Mülheim an der Ruhr, Germany. She is also an Adjunct Professor in the Department of Chemistry and Chemical Biology at Cornell University, an honorary faculty member at both Ruhr University in Bochum and University of Duisburg Essen, and the group leader of the PINK Beamline at the Energy Materials In‐Situ Laboratory at Helmholtz Zentrum in Berlin. She received her B.S. in Chemistry at Southwestern University in 1995 and her Ph.D. from Stanford University in 2002. From 2002-2009, she was a staff scientist at the Stanford Synchrotron Radiation Laboratory, before moving to her faculty position at Cornell. She is the recipient of a European Research Council Synergy Award (2019), the American Chemical Society Inorganic Chemistry Lectureship Award (2016), the Society of Biological Inorganic Chemistry Early Career Award (2015), a European Research Council Consolidator Award (2013), a Kavli Fellowship (2012), and an Alfred P. Sloan Research Fellowship (2011). Recently, she received the Seaborg Lectureship Award from UC Berkeley (2023), the R. J. P. Williams lectureship from Oxford (2022) and the Michael Lappert lectureship from the Royal Society of Chemistry (2024). She served as an associate editor for RSC Chemical Science from (2018-2024) and recently moved to the ACS as an associate editor for JACS (2024-present). Research in the DeBeer group is focused on the development and application of advanced X-ray spectroscopic tools for understanding key mechanisms in biological and chemical catalysis.
