Homonuclear chemical shift correlation in rotating solids via RN? n symmetry-based adiabatic RF pulse schemes.

The efficacy of RN^? _n symmetry-based adiabatic Zero-Quantum (ZQ) dipolar recoupling schemes for obtaining chemical shift correlation data at moderate magic angle spinning frequencies has been evaluated. RNsequences generally employ basic inversion elements that correspond to a net 180° rotation about the rotating framex-axis. It is shown here via numerical simulations and experimental measurements that it is also possible to achieve efficient ZQ dipolar recoupling via RNschemes employing adiabatic pulses. Such an approach was successfully used for obtaining¹3C chemical shift correlation spectra of a uniformly labelled sample of (CUG)₉7- a triplet repeat expansion RNA that has been implicated in the neuromuscular disease myotonic dystrophy. An analysis of the¹3C sugar carbon chemical shifts suggests, in agreement with our recent¹5N MAS-NMR studies, that this RNA adopts an A-helical conformation. [ABSTRACT FROM AUTHOR]