Proton Assisted Recoupling at High Spinning Frequencies

We demonstrate the successful application of C-13-C-13 proton assisted recoupling (PAR) on [U-C-13,N-15] N-f-MLF-OH and [U-C-13,N-15] protein GBI at high magic angle spinning (MAS) frequencies (omega(r)/2 pi = 65 kHz). Specifically, by combining PAR mixing with low power heteronuclear decoupling (omega(1H)/2(pi) similar to 16 kHz) and high spinning frequencies, we obtain high resolution 2D spectra displaying long-range C-13-C-13 contacts from which distance estimates call be extracted. These experiments therefore demonstrate the possibility of performing high resolution Structural studies in the limit of high spinning frequency and low power H-1 decoupling, a regime which optimizes the resolution of protein samples and preserves their integrity.