References:
S.W. Fesik and E.R.P. Zuiderweg (1988) J. Magn. Reson. 78 588-593. (Link to Article)

Minimum labelling: ¹³C

Dimensions: 3

First there is an HMQC step in which magnetisation is transferred from ¹H to ¹³C and back again. This is then followed by a NOESY step in which the magnetisation is transferred to any other hydrogen nucleus close by. This is followed by detection.

This spectrum is used to obtain restraints for structure calculations. It will usually be recorded with 100% D₂O as the solvent – this minimises artefacts. Its advantage over the ¹³C-NOESY-HSQC, is that the NOESY dimension is the directly detected one, and therefore the resolution in the NOESY dimension is significantly increased. A further advantage, is that the aliphatic and aromatic carbon regions can both be included in one spectrum and the aromatic region can be extremely useful for the assignment of the aromatic residues.