Sparsely sampled high-resolution 4-D experiments for efficient backbone resonance assignment of disordered proteins

► Alternative chemical shift evolution schemes are used to construct new experiments. ► 4-D HA(CA)CO(CA)NH/ HA(CA)CONH experiments complement existing experiments. ► Sparse sampling enables efficient data collection for backbone assignment of IDPs. ► FFT-CLEAN produces high-quality spectra even with less-than-optimal sampling schemes.