Abstract
Obtaining atomic-level information on components in the cell is a major focus in structural biology. Elucidating specific structural and dynamic features of proteins and their interactions in the cellular context is crucial for understanding cellular processes. We introduce (19)F dynamic nuclear polarization (DNP) combined with fast magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy as a powerful technique to study proteins in mammalian cells. We demonstrate our approach on the severe acute respiratory syndrome coronavirus 2 5F-Trp-N(NTD) protein, electroporated into human cells. DNP signal enhancements of 30- to 40-fold were observed, translating into over 1000-fold experimental time savings. High signal-to-noise ratio spectra were acquired on nanomole quantities of a protein in cells in minutes. 2D (19)F-(19)F dipolar correlation spectra with remarkable sensitivity and resolution were obtained, exhibiting (19)F-(19)F cross peaks associated with fluorine atoms as far as ~10 angstroms apart. This work paves the way for (19)F DNP-enhanced MAS NMR applications in cells for probing protein structure, dynamics, and ligand interactions.