S. Grzesiek and A. Bax (1992) J. Am. Chem. Soc. 114 6291-6293. (Link to Article)
Minimum labelling: 15N, 13C
Magnetisation is transferred from 1Hα and 1Hβ to 13Cα and 13Cβ, respectively, and then from 13Cβ to 13Cα. From here it is transferred first to13CO, then to 15NH and then to 1HN for detection. The chemical shift is evolved simultaneously on 13Cα and 13Cβ, so these appear in one dimension. The chemical shifts evolved in the other two dimensions are 15NH and 1HN. The chemical shift is not evolved on 13CO.
Along with the CBCANNH and HSQC this forms the standard set of experiments needed for backbone assignment. For large proteins the signal-to-noise may not be great and assignment using the HNCA, HN(CO)CA, HNCO and HN(CA)CO may form a better strategy. When using deuterated protein, the spectrum has to be recorded as an ‘out-and-back’ method and the signal-to-noise suffers even further.