Serena DeBeer

Serena DeBeer (born 1973) is an American chemist. She is currently a W3-Professor and the director at the Max Planck Institute for Chemical Energy Conversion in Muelheim an der Ruhr, Germany, where she heads the Department of Inorganic Spectroscopy. Her expertise lies in the application and development of X-ray based spectroscopic methods as probes of electronic structure in biological and chemical catalysis.

Prof. Dr.

Serena DeBeer
Born1973 (1973)
NationalityAmerican
Other namesSerena DeBeer George
EducationChemistry Southwestern University, TX
PhD Stanford University (2002)
Known forX-ray spectroscopy
nitrogenase
photosystem II
hydrogenase
Methane monooxygenase
Scientific career
FieldsChemistry
InstitutionsSSRL SLAC Stanford University (2001–2009)
Cornell University (2009-present)
Ruhr University Bochum (2014–present)
Max Planck Institute for Chemical Energy Conversion (2011–present)
Doctoral advisorEdward I. Solomon
Keith O. Hodgson

Education and career

Serena DeBeer studied at Southwestern University, Georgetown, TX (USA) where she completed her bachelor program in Chemistry, with minor in Mathematics in 1995 (with honors). She received her doctorate from Stanford University in 2002, working under the guidance of Edward I. Solomon and Keith O. Hodgson. She then moved to SLAC National Accelerator Laboratory, where she worked first as a beamline scientist (2001–2003) at the Stanford Synchrotron Radiation Laboratory, and later as staff scientist (2003–2009). In the Fall of 2009, she relocated to Cornell University in Ithaca, NY (USA), where she accepted a faculty position as Assistant Professor at the Department of Chemistry and Chemical Biology.[1] In the Summer of 2011, she moved to Germany and started to work as a W2-Professor and research group leader at the Max Planck Institute for Bioinorganic Chemistry (since 2012 Max Planck Institute for Chemical Energy Conversion, MPI CEC) in Mülheim an der Ruhr, Germany. Since 2012 she has held the position of an Adjunct Professor at Cornell University as well as an Honorary Faculty position at Ruhr University Bochum since 2014.[2] DeBeer headed the research group "X-ray Spectroscopy" at MPI CEC until 2017 when she was appointed director at this institute and promoted to a W3-Professor. Currently she leads the department of "Inorganic Spectroscopy"[3] at MPI CEC. Additionally, she is the group leader of the PINK beamline[4] project at the Energy and Materials In-Situ Laboratory[5] at the Helmholtz Zentrum Berlin, Germany.

Research

Research in the DeBeer group focuses on answering  fundamental questions in energy research. Namely, how does one reversibly store and release energy from chemical bonds using earth abundant transition metals? And how is this done most efficiently? Her research group studies homogeneous, heterogeneous and biological catalysts in order to answer these questions, with a primary focus on enzymatic catalysis. She is an expert in the application of advanced X-ray spectroscopy to understand catalytic transformations.

Nitrogenase

A strong focus of her research is to study the enzyme that is responsible for the conversion of dinitrogen (N2) to ammonia (NH3)—Nitrogenase. Serena DeBeer and her group study this remarkable system comprising a FeMo cofactor (FeMoco) as its active site, and structural model complexes utilizing high-resolution X-ray absorption (XAS) and X-ray emission spectroscopy (XES). Through this work, great progress has been made in understanding the structure of this active site. A key contribution was a spectroscopic identification of the central atom in the active site as a carbide.[6] Moreover, the application of high-resolution XAS spectroscopy supported with theoretical calculations, allowed her group to succeed in the assignment of the oxidation state of the Mo atom in the FeMoco as Mo(III).[7] This study was followed up later with the experimental evidence of a non-Hund spin configuration at the Mo atom by means of X-ray Magnetic Circular Dichroism (XMCD) spectroscopy.[8] Another approach in this field concerns comparative studies of different forms of nitrogenase enzymes with FeMoco and FeVco active sites,[9] Selenium-incorporated FeMoco,[10] as well as spectroscopic characterization of the first intermediate state of the nitrogenase catalytic cycle (E1).[11][12]

Methane monooxygenase

Another important chemical conversion studied by her group is the catalytic oxidation of methane to methanol. Nature utilizes a group of enzymes called methane monooxygenase (MMOs). The active site of this enzyme that enables the cleavage of the C-H of methane is a dinuclear Fe(IV) intermediate Q found in the hydroxylase protein (MMOH) of MMO. Spectroscopic studies in the DeBeer group have provided new insights into the structure of this diiron complex. Through applications of advanced X-ray spectroscopic studies like high-resolution XAS they characterized the key intermediate in biological methane oxidation as an open-core diiron structure (with FeIV=O motif).[13] Additional EXAFS studies confirmed this finding by showing no evidence for a short Fe-Fe distance but rather a long diiron distance consistent with an open-core structure.[14]

Spectroscopy Development

Recent work of DeBeer's group has focused on developing the full information content of various X-ray spectroscopic methods and their application to biological catalysts.

Among these methods are:

Valence X-ray Emission Spectroscopy

In this method (also known as VtC XES = Valence-to-Core X-ray Emission Spectroscopy), one monitors the resultant fluorescence after a valence electron refills the ionized metal 1s core hole. As such, valence XES spectra provide a map of ligand ionization energies, and provides information on both ligand identity and protonation state. A prominent application of this method its use to identify the central carbon atom in FeMo cofactor of Nitrogenase (see section Nitrogenase).[6]

Resonant valence XES (RXES) or Resonant Inelastic X-ray Scattering (RIXS)

The DeBeer group is actively involved in the development and application of RXES/RIXS based methods in both the hard and soft X-ray regime. These include 1s-Valence RIXS as a means to obtain ligand-selective XAS[15] and 2p3d RIXS as a means to map out the d-d excitations.[16][17][18][19][20][21]

X-ray Magnetic Circular Dichroism (XMCD)

This method has been extensively used in solid-state materials, to determine the magnetic properties. Past applications to (bio-)inorganic or protein systems were lacking proper qualitative and quantitative interpretations. DeBeer's group expanded the information that can be obtained from XMCD of covalent systems.[22] To date, this been the only one method able to provide evidence for the proposed non-Hund configuration at the Mo atom in Nitrogenase[8] (see section Nitrogeanse).

A laboratory based dispersive X-ray Emission Spectrometer

The group of Serena DeBeer in collaboration with the group of Prof. Birgit Kangießer at TU Berlin, developed an in-house dispersive X-ray Emission Spectroscopy (XES) setup. The setup that utilizes a laboratory X‑ray source (Metal Jet) in combination with a von Hamos full cylinder optic with Highly Annealed Pyrolytic Graphite (HAPG) crystal and a CCD detector. This allows obtaining spectra in the 2.4-9 keV range. Moreover, this spectrometer is an alternative to synchrotron-based beamlines for concentrated samples.[23]

PINK Beamline

The DeBeer group is also leading the development of the PINK beamline[4] at the Energy Materials In-situ Laboratory[5] at the Helmholtz Zentrum Berlin. Dr. Sergey Peredkov is the lead designer and instrument scientist for this project. This beamline operates in 2-10 keV energy regime, either in a “pink” beam mode with multilayer mirror or with monochromatic beam (by addition of a double crystal monochromator). The beamline is presently in a commissioning phase.

Awards and recognition

References
  1. "Serena DeBeer | Chemistry & Chemical Biology Cornell Arts & Sciences".
  2. "Honorarprofessorin der RUB ist neue Direktorin". news.rub.de (in German). Retrieved 2019-08-08.
  3. "Prof. Dr. Serena DeBeer". cec.mpg.de. Retrieved 2019-12-02.
  4. Energie, Helmholtz-Zentrum Berlin für Materialien und. "PINK". HZB Website. Retrieved 2019-12-02.
  5. Energie, Helmholtz-Zentrum Berlin für Materialien und. "Energy Materials In-Situ Laboratory Berlin". HZB Website. Retrieved 2019-12-02.
  6. Lancaster, K. M.; Roemelt, M.; Ettenhuber, P.; Hu, Y.; Ribbe, M. W.; Neese, F.; Bergmann, U.; DeBeer, S. (2011-11-18). "X-ray Emission Spectroscopy Evidences a Central Carbon in the Nitrogenase Iron-Molybdenum Cofactor". Science. 334 (6058): 974–977. Bibcode:2011Sci...334..974L. doi:10.1126/science.1206445. ISSN 0036-8075. PMC 3800678. PMID 22096198.
  7. Bjornsson, Ragnar; Lima, Frederico A.; Spatzal, Thomas; Weyhermüller, Thomas; Glatzel, Pieter; Bill, Eckhard; Einsle, Oliver; Neese, Frank; DeBeer, Serena (2014). "Identification of a spin-coupled Mo(III) in the nitrogenase iron–molybdenum cofactor". Chem. Sci. 5 (8): 3096–3103. doi:10.1039/C4SC00337C. ISSN 2041-6520.
  8. Kowalska, Joanna K.; Henthorn, Justin T.; Van Stappen, Casey; Trncik, Christian; Einsle, Oliver; Keavney, David; DeBeer, Serena (2019-07-08). "X-ray Magnetic Circular Dichroism Spectroscopy Applied to Nitrogenase and Related Models: Experimental Evidence for a Spin-Coupled Molybdenum(III) Center". Angewandte Chemie International Edition. 58 (28): 9373–9377. doi:10.1002/anie.201901899. PMC 6772009. PMID 31119827.
  9. Rees, Julian A.; Bjornsson, Ragnar; Kowalska, Joanna K.; Lima, Frederico A.; Schlesier, Julia; Sippel, Daniel; Weyhermüller, Thomas; Einsle, Oliver; Kovacs, Julie A.; DeBeer, Serena (2017). "Comparative electronic structures of nitrogenase FeMoco and FeVco". Dalton Transactions. 46 (8): 2445–2455. doi:10.1039/C7DT00128B. ISSN 1477-9226. PMC 5322470. PMID 28154874.
  10. Henthorn, Justin T.; Arias, Renee J.; Koroidov, Sergey; Kroll, Thomas; Sokaras, Dimosthenis; Bergmann, Uwe; Rees, Douglas C.; DeBeer, Serena (2019-08-28). "Localized Electronic Structure of Nitrogenase FeMoco Revealed by Selenium K-Edge High Resolution X-ray Absorption Spectroscopy". Journal of the American Chemical Society. 141 (34): 13676–13688. doi:10.1021/jacs.9b06988. ISSN 0002-7863. PMC 6716209. PMID 31356071.
  11. Van Stappen, Casey; Thorhallsson, Albert Thor; Decamps, Laure; Bjornsson, Ragnar; DeBeer, Serena (2019). "Resolving the structure of the E 1 state of Mo nitrogenase through Mo and Fe K-edge EXAFS and QM/MM calculations". Chemical Science. 10 (42): 9807–9821. doi:10.1039/C9SC02187F. ISSN 2041-6520.
  12. Van Stappen, Casey; Davydov, Roman; Yang, Zhi-Yong; Fan, Ruixi; Guo, Yisong; Bill, Eckhard; Seefeldt, Lance C.; Hoffman, Brian M.; DeBeer, Serena (2019-09-16). "Spectroscopic Description of the E 1 State of Mo Nitrogenase Based on Mo and Fe X-ray Absorption and Mössbauer Studies". Inorganic Chemistry. 58 (18): 12365–12376. doi:10.1021/acs.inorgchem.9b01951. ISSN 0020-1669. PMC 6751781. PMID 31441651.
  13. Castillo, Rebeca G.; Banerjee, Rahul; Allpress, Caleb J.; Rohde, Gregory T.; Bill, Eckhard; Que, Lawrence; Lipscomb, John D.; DeBeer, Serena (2017-12-13). "High-Energy-Resolution Fluorescence-Detected X-ray Absorption of the Q Intermediate of Soluble Methane Monooxygenase". Journal of the American Chemical Society. 139 (49): 18024–18033. doi:10.1021/jacs.7b09560. ISSN 0002-7863. PMC 5729100. PMID 29136468.
  14. Cutsail, George E.; Banerjee, Rahul; Zhou, Ang; Que, Lawrence; Lipscomb, John D.; DeBeer, Serena (2018-12-05). "High-Resolution Extended X-ray Absorption Fine Structure Analysis Provides Evidence for a Longer Fe···Fe Distance in the Q Intermediate of Methane Monooxygenase". Journal of the American Chemical Society. 140 (48): 16807–16820. doi:10.1021/jacs.8b10313. ISSN 0002-7863. PMC 6470014. PMID 30398343.
  15. Hall, Eleanor R.; Pollock, Christopher J.; Bendix, Jesper; Collins, Terrence J.; Glatzel, Pieter; DeBeer, Serena (2014-07-16). "Valence-to-Core-Detected X-ray Absorption Spectroscopy: Targeting Ligand Selectivity". Journal of the American Chemical Society. 136 (28): 10076–10084. doi:10.1021/ja504206y. ISSN 0002-7863. PMID 24946007.
  16. Van Kuiken, Benjamin E.; Hahn, Anselm W.; Nayyar, Brahamjot; Schiewer, Christine E.; Lee, Sonny C.; Meyer, Franc; Weyhermüller, Thomas; Nicolaou, Alessandro; Cui, Yi-Tao; Miyawaki, Jun; Harada, Yoshihisa (2018-06-18). "Electronic Spectra of Iron–Sulfur Complexes Measured by 2p3d RIXS Spectroscopy". Inorganic Chemistry. 57 (12): 7355–7361. doi:10.1021/acs.inorgchem.8b01010. ISSN 0020-1669. PMID 29847108.
  17. Hahn, Anselm W.; Van Kuiken, Benjamin E.; al Samarai, Mustafa; Atanasov, Mihail; Weyhermüller, Thomas; Cui, Yi-Tao; Miyawaki, Jun; Harada, Yoshihisa; Nicolaou, Alessandro; DeBeer, Serena (2017-07-17). "Measurement of the Ligand Field Spectra of Ferrous and Ferric Iron Chlorides Using 2p3d RIXS". Inorganic Chemistry. 56 (14): 8203–8211. doi:10.1021/acs.inorgchem.7b00940. ISSN 0020-1669. PMID 28653856.
  18. Hahn, Anselm W.; Van Kuiken, Benjamin E.; Chilkuri, Vijay Gopal; Levin, Natalia; Bill, Eckhard; Weyhermüller, Thomas; Nicolaou, Alessandro; Miyawaki, Jun; Harada, Yoshihisa; DeBeer, Serena (2018-08-06). "Probing the Valence Electronic Structure of Low-Spin Ferrous and Ferric Complexes Using 2p3d Resonant Inelastic X-ray Scattering (RIXS)". Inorganic Chemistry. 57 (15): 9515–9530. doi:10.1021/acs.inorgchem.8b01550. ISSN 0020-1669. PMID 30044087.
  19. Van Kuiken, Benjamin E.; Hahn, Anselm W.; Maganas, Dimitrios; DeBeer, Serena (2016-11-07). "Measuring Spin-Allowed and Spin-Forbidden d–d Excitations in Vanadium Complexes with 2p3d Resonant Inelastic X-ray Scattering". Inorganic Chemistry. 55 (21): 11497–11501. doi:10.1021/acs.inorgchem.6b02053. ISSN 0020-1669. PMID 27731986.
  20. Maganas, Dimitrios; DeBeer, Serena; Neese, Frank (2017-10-02). "A Restricted Open Configuration Interaction with Singles Method To Calculate Valence-to-Core Resonant X-ray Emission Spectra: A Case Study". Inorganic Chemistry. 56 (19): 11819–11836. doi:10.1021/acs.inorgchem.7b01810. ISSN 0020-1669. PMC 5692824. PMID 28920680.
  21. Al Samarai, Mustafa; Hahn, Anselm W.; Beheshti Askari, Abbas; Cui, Yi-Tao; Yamazoe, Kosuke; Miyawaki, Jun; Harada, Yoshihisa; Rüdiger, Olaf; DeBeer, Serena (2019-10-23). "Elucidation of Structure–Activity Correlations in a Nickel Manganese Oxide Oxygen Evolution Reaction Catalyst by Operando Ni L-Edge X-ray Absorption Spectroscopy and 2p3d Resonant Inelastic X-ray Scattering". ACS Applied Materials & Interfaces. 11 (42): 38595–38605. doi:10.1021/acsami.9b06752. ISSN 1944-8244. PMID 31523947.
  22. Kowalska, Joanna K.; Nayyar, Brahamjot; Rees, Julian A.; Schiewer, Christine E.; Lee, Sonny C.; Kovacs, Julie A.; Meyer, Franc; Weyhermüller, Thomas; Otero, Edwige; DeBeer, Serena (2017-07-17). "Iron L 2,3 -Edge X-ray Absorption and X-ray Magnetic Circular Dichroism Studies of Molecular Iron Complexes with Relevance to the FeMoco and FeVco Active Sites of Nitrogenase". Inorganic Chemistry. 56 (14): 8147–8158. doi:10.1021/acs.inorgchem.7b00852. ISSN 0020-1669. PMC 5516708. PMID 28653855.
  23. Malzer, Wolfgang; Grötzsch, Daniel; Gnewkow, Richard; Schlesiger, Christopher; Kowalewski, Fabian; Van Kuiken, Benjamin; DeBeer, Serena; Kanngießer, Birgit (November 2018). "A laboratory spectrometer for high throughput X-ray emission spectroscopy in catalysis research". Review of Scientific Instruments. 89 (11): 113111. Bibcode:2018RScI...89k3111M. doi:10.1063/1.5035171. ISSN 0034-6748. PMID 30501328.
  24. "ERC Synergy Grant for Serena DeBeer and an international and interdisciplinary team". cec.mpg.de. Retrieved 2019-11-27.
  25. "ERC 2019 Synergy Grants examples". ERC: European Research Council. 2019-10-10. Retrieved 2019-11-27.
  26. "Serena DeBeer joins Chemical Science as an Associate Editor – Chemical Science Blog". Retrieved 2019-11-27.
  27. "Dr. Serena Debeer - 2016 Inorganic Chemistry Le... | ACS Network". communities.acs.org. Retrieved 2019-11-27.
  28. "Serena DeBeer SBIC Early Career Award".
  29. "ERC Consolidator Grant: N2ase".
  30. "Serena DeBeer". www.nasonline.org. Retrieved 2019-11-27.
  31. "Past Fellows". sloan.org. Retrieved 2019-11-27.
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