New techniques in high-resolution nuclear magnetic resonance: Novel pulse sequences and high-dimensional spectra

A new strategy to obtain high-dimensional NMR spectra with very narrow resonances along all of the frequency axes (even those with sparse sampling) is described. New selective 180° and 90° pulses also described for protein backbone assignment experiments are presented for their applications. Optimized 2D 1H-15N HSQC, 3D CT-HNCO, 3D CT-HN(CO)CA and 4D CT-HNCOCA experiments are described and demonstrated on labeled protein samples. A novel selective heteronuclear Hartmann-Hahn (SHEHAHA) pulse sequence is also described. It has the advantage of suppressing redundant information in the frequency domain caused by unavoidable, but unwanted homonuclear Hartmann-Hahn transfer during heteronuclear Hartmann-Hahn transfer.