Fast (4,3)D GFT-TS NMR for NOESY of small to medium-sized proteins

NOESY NMR spectra provide interproton distance information for a molecule in solution and the complete, unambiguous determination of NOESY spectral assignments is the basis for protein structure determination. High resolution NOESY can be obtained from 13C and 15N isotope edited four-dimensional (4D) data, but these experiments would normally require weeks to complete. We have applied a G-matrix Fourier transform and time-sharing (GFT-TS) NMR method for simultaneously acquiring two sets of 4D NOESY data. The implementation of the GFT-TS allows 2.5- to 5-fold reduction in experimental time without sacrificing spectral resolution as compared with that of 3D data. The 13C, 15N-edited GFT-TS (4,3)D H-N-CN-H NOESY (GFT dimensions are underlined and TS dimensions are in italics) provides convenient and unambiguous NOE assignments for HN/HN and HN/HC for a sample of 1.4 mM ubiquitin (76 amino acids, 8.5 kDa). We also provide a set of utility scripts for data processing and spectral assignment to facilitate the use of GFT NMR. This method shows great promise for routine high quality NMR NOESY data collection for small to medium sized proteins.