Making and Breaking Bonds: Advanced X-ray Spectroscopic Studies of Energy Converting Enzymes

The efficient and reversible storage and release of energy in chemical bonds is an essential aspect, and a great challenge in energy research.  The activation of small molecules (N₂, O₂, CO₂) can be achieved by homogenous, heterogeneous and biological catalysts. Of the possible metal catalysts, nature is unsurpassed in terms of facilitating small molecule activation with stunning efficiency and selectivity.  This has inspired much fundamental research directed towards understanding the enzymatic mechanisms on an atomic level. In this talk, I will discuss recent studies using advanced X-ray spectroscopic approaches, as well as laboratory spectroscopy, to understand the biological dinitrogen reduction and C-H bond activation on a molecular level.  I will also discuss recent advances using phosphorus X-ray emission spectroscopy (XES) to understand transformations of biomolecules, which has broad applicability in biological energy transduction. Finally, applications of 1s3p and 2p3d resonant inelastic X-ray scattering (RIXS) to enzymes will be highlighted.

References:

Gomez Castillo, R., Hahn, A. W., van Kuiken, B. E., Henthorn, J. T., McGale, J., DeBeer, S. (2021) Probing Physical Oxidation State by Resonant X-ray Emission Spectroscopy: Applications to Iron Model Complexes and Nitrogenase. Angew. Chem., Inter. Ed., (60), 2-12. doi:10.1002/anie.202015669.

Mathe, Z., McCubbin Stepanic, O., Peredkov, S.,  DeBeer, S. (2021) Phosphorus K beta X-ray emission spectroscopy detects non-covalent interactions of phosphate biomolecules in situ. Chem. Sci. doi:10.1039/d1sc01266e.

Henthorn, J.T., DeBeer, S. (2022) Selenium Valence-to-Core X-ray Emission Spectroscopy and Kβ HERFD X-ray Absorption Spectroscopy as Complementary Probes of Chemical and Electronic Structure. Inorg. Chem. 61 (6), 2760-2767. doi:10.1021/acs.inorgchem.1c02802

Henthorn, J.T., Arias, R.J., Koroidov, S., Kroll, T., Sokaras, D., Bergmann, U., Rees, D.C., DeBeer, S. (2019). Localized Electronic Structure of Nitrogenase FeMoco Revealed by Selenium K-edge High Resolution X-ray Absorption Spectroscopy. J. Am. Chem. Soc. 141(34), 13676-13688.  doi:10.1021/jacs.9b06988