Protein NMR resonance assignment by isotropic mixing experiments on random fractionally deuterated samples.
The 108-residue protein E. coli thioredoxin has been uniformly enriched to 50% with deuterium at all carbon-bound hydrogen positions. Isotropic mixing (i.e. TOCSY) experiments have been conducted for both the deuterated and natural-abundance samples. Using a 54 ms mixing time correlation peaks can be seen for all four protons on the benzenoid ring of tryptophan in both samples. The deuteration results in an average decrease in cross-sectional area of a factor of 2-3 for the TOCSY cross-peaks. The cross-peak intensities for the deuterated sample systematically decrease as a function of the number of protons involved in the transfer process thus overcoming a common ambiguity in the TOCSY experiment.
LeMaster
D M
DM
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511.
D001426:Bacterial Proteins; D004926:Escherichia coli / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011487:Protein Conformation; D013879:Thioredoxins
D001426:Bacterial Proteins; D013879:Thioredoxins