Amino acid type identification in NMR spectra of proteins via beta- and gamma-carbon edited experiments.

Two experiments are presented that yield amino acid type identification of individual residues in a protein by editing the 1H–15N correlations into four different 2D subspectra, each corresponding to a different amino acid type class, and that can be applied to deuterated proteins. One experiment provides information on the amino acid type of the residue preceding the detected amide 1H–15N correlation, while the other gives information on the type of its own residue. Versions for protonated proteins are also presented, and in this case it is possible to classify the amino acids into six different classes. Both sequential and intraresidue experiments provide highly complementary information, greatly facilitating the assignment of protein resonances. The experiments will also assist in transferring the assignment of a protein to the spectra obtained under different experimental conditions (e.g. temperature, pH, presence of ligands, cofactors, etc.).