Proton Assisted Recoupling at High Spinning Frequencies

Abstract

We demonstrate the successful application of [superscript 13]C−[superscript 13]C proton assisted recoupling (PAR) on [U−[superscript 13]C,[superscript 15]N] N-f-MLF-OH and [U−13C,15N] protein GB1 at high magic angle spinning (MAS) frequencies (ω[subscript r]/2π = 65 kHz). Specifically, by combining PAR mixing with low power heteronuclear decoupling (ω[subscript 1H]/2π~16 kHz) and high spinning frequencies, we obtain high resolution 2D spectra displaying long-range [superscript 13]C−[superscript 13]C contacts from which distance estimates can be extracted. These experiments therefore demonstrate the possibility of performing high resolution structural studies in the limit of high spinning frequency and low power [superscript 1]H decoupling, a regime which optimizes the resolution of protein samples and preserves their integrity.