Heteronuclear single quantum coherence (HSQC)
In HSQC experiments, signals from two different nuclei are recorded.
It is particularly useful in protein NMR, where 1H-15N spectra are obtained in order to fingerprint the protein backbone. Proteins are therefore isotopically labeled with 15N because the naturally occurring 14N is not an active in NMR experiments.
The resulting 2D spectrum depicts the protons on one, and the nitrogens on the other axis.
Figure 1: HSQC of gentamicin-megalin interaction