The use of selective deuteration for the sequence specific 1H NMR assignment of larger proteins

The possibility of extending NMR methods for structure determination to larger proteins (MW > 10 kD) depends on the development of isotopic labeling protocols for the simplification of their NMR spectra (isotopic spectral editing). We describe here the successful use of selective deuteration to obtain sequence specific assignments for (thus far) more than 50% of the residues of the trp repressor protein (25 kD). This is the largest protein for which detailed sequence specific assignments have been attempted to-date.