https://doi.org/10.1351/goldbook.08309
Three-dimensional nuclear magnetic resonance spectroscopy for the assignment of protein structure with one nitrogen and two hydrogen dimensions.
Note: An isotropic mixing step transfers magnetization between \(\ce{^{1}H}\) spins. Then the magnetization is transferred to neighbouring \(\ce{^{15}N}\) nuclei and back to \(\ce{^{1}H}\) for detection. This can help identify amino acid types.
See also: total correlation spectroscopy