Phosphorus Kβ X-ray emission spectroscopy detects non-covalent interactions of phosphate biomolecules <i>in situ</i>
Zachary Mathe, Olivia McCubbin Stepanic, Sergey Peredkov, Serena DeBeer
Abstract
ATP). Kβ X-ray emission spectroscopy (XES) of phosphorus has been largely unexplored, with no previous applications to biomolecules. Here, the potential of P Kβ XES to study phosphate-containing biomolecules, including ATP and NADPH, is evaluated, as is the application of the technique to aqueous solution samples. P Kβ spectra offer a detailed picture of phosphate valence electronic structure, reporting on subtle non-covalent effects, such as hydrogen bonding and ionic interactions, that are key to enzymatic catalysis. Spectral features are interpreted using density functional theory (DFT) calculations, and potential applications to the study of biological energy conversion are highlighted.