Exploring Sulfur Sites in Proteins via Triple-Resonance 1H-Detected 77Se NMR

NMR spectroscopy has been applied to virtually all sites within proteins and biomolecules; however, the observation of sulfur sites remains very challenging. Recent studies have examined 77Se as a replacement for sulfur and applied 77Se NMR in both the solution and solid states. As a spin-1/2 nuclide, 77Se is attractive as a probe of sulfur sites, and it has a very large chemical shift range (due to a large chemical shift anisotropy), which makes it potentially very sensitive to structural and/or binding interactions as well as dynamics. Despite being a spin-1/2 nuclide, there have been rather limited studies of 77Se, and the ability to use 1H-indirect detection has been sparse. Some examples exist, but in the absence of a directly bonded, nonexchangeable 1H, these have been largely limited to smaller molecules. We develop and illustrate approaches using double-labeling of 13C and 77Se in proteins that enable more sensitive triple-resonance schemes via multistep coherence transfers and 1H-detection. These methods require specialized hardware and decoupling schemes, which we developed and will be discussed.
This article was originally published in Journal of the American Chemical Society. The version of record is available at: https://doi.org/10.1021/jacs.3c07225. Copyright © 2023 The Authors. Published by American Chemical Society.
Koscielniak, Janusz, Jess Li, Deepak Sail, Rolf Swenson, Clemens Anklin, Sharon Rozovsky, and R. Andrew Byrd. “Exploring Sulfur Sites in Proteins via Triple-Resonance 1H-Detected 77Se NMR.” Journal of the American Chemical Society 145, no. 45 (November 15, 2023): 24648–56. https://doi.org/10.1021/jacs.3c07225.