Super resolution NOESY spectra of proteins.

Spectral resolution remains one of the most significant limitations in the NMR study of biomolecules. We present the srNOESY (super resolution nuclear overhauser effect spectroscopy) experiment, which enhances the resolution of NOESY cross-peaks at the expense of the diagonal peak line-width. We studied two proteins, ubiquitin and the influenza hemagglutinin fusion peptide in bicelles, and we achieved average resolution enhancements of 21-47% and individual peak enhancements as large as ca. 450%. New peaks were observed over the conventional NOESY experiment in both proteins as a result of these improvements, and the final structures generated from the calculated restraints matched published models. We discuss the impact of the experimental parameters, spin diffusion and the information content of the srNOESY lineshape.