The 3D HN(CO)C) experiment allows the measurement of J(CO-CO) coupling constants in ¹³C,¹⁵N-labeled proteins using the quantitative J-correlation approach. In addition, it can be used to measure the corresponding J(CO-CG) mcoupling constants in Asn and Asp residues.

Implementation on AVANCE spectrometers equipped with a third channel and pulsed field gradients (PFGs).

The experiment has been described in 96JACS8170 . A related scheme (3D (HN)CO(CO)NH) experiment) less sensitive to transverse 13CO relaxation has been reported ( 97JB207 ) in which the COSY step has been replaced by a 13C-13C TOCSY step.

The 3D HN(CO)CO experiment affords a 3D map with (F1,F2,F3=N,CO,NH) in which coupling constants are extracted from intensity ratio of the corresponding cross-peak and internal diagonal reference peak.