Aladin, Victoria, Marc Vogel, Robert Binder, Irene Burghardt, Beatrix Suess, and Björn Corzilius. “Complex Formation of the Tetracycline‐Binding Aptamer Investigated by Specific Cross‐Relaxation under DNP.” Angewandte Chemie 131, no. 15 (April 2019): 4917–22.
While dynamic nuclear polarization (DNP) under magic-angle spinning (MAS) is generally a powerful method capable of greatly enhancing the sensitivity of solid-state NMR spectroscopy, hyperpolarization also gives rise to peculiar spin dynamics. Here, we elucidate how specific cross-relaxation enhancement by active motions under DNP (SCREAM-DNP) can be utilized to selectively obtain MAS-NMR spectra of an RNA aptamer in a tightly bound complex with a methylbearing ligand (tetracycline) due to the effective CH3-reorientation at an optimized sample temperature of approximately 160 K. SCREAM-DNP can spectrally isolate the complex from non-bound species in an RNA mixture. This selectivity allows for a competition assay between the aptamer and a mutant with compromised binding affinity. Variations in molecular structure and methyl dynamics, as observed by SCREAM-DNP, between free tetracycline and RNA-bound tetracycline are discussed.