Complex Formation of the Tetracycline-Binding Aptamer Investigated by Specific Cross-Relaxation under DNP

Angew Chem Int Ed Engl. 2019 Apr 1;58(15):4863-4868. doi: 10.1002/anie.201811941. Epub 2019 Mar 8.


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 methyl-bearing 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.

Keywords: NMR spectroscopy; RNA; aptamer; cross relaxation; dynamic nuclear polarization.

Publication types

  • Research Support, Non-U.S. Gov't