Cost-effective selective deuteration of aromatic amino acid residues produces long-lived solution H NMR magnetization in proteins.

Solution NMR studies of large proteins are hampered by rapid signal decay due to short-range dipolar H-H and H-C interactions. These are attenuated by rapid rotation in methyl groups and by deuteration (H), so selective H,C-isotope labelling of methyl groups in otherwise perdeuterated proteins, combined with methyl transverse relaxation optimized spectroscopy (methyl-TROSY), is now standard for solution NMR of large protein systems > 25 kDa. For non-methyl positions, long-lived magnetization can be introduced as isolated H-C groups.