Kinetics of hydrogen-deuterium exchange of tryptophan and tryptophan peptides in deutero-trifluoroacetic acid using proton magnetic resonance spectroscopy

Raymond S. Norton, J. Howard Bradbury

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10 Citations (Scopus)

Abstract

The methods which have been used for the observation and assignment of resonances in the NMR spectra of proteins are reviewed. One such method, the selective deuteration of the aromatic protons of tryptophyl residues, is studied by NMR spectroscopy in model compounds in this paper, and in proteins in the following paper. On the basis of a reassignment of the PMR spectrum of the aromatic protons of L-tryptophan, the relative rates of H-D exchange in deutero-trifluoroacetic acid (d-TFA) are H-2 > H-5 > H-6 > H-4 - H-7. The energies of activation for the first order exchange of both the H-2 and H-5 protons is 12 k.cal.mol-1. The rate constant for exchange of the H-2 protons of tryptophyl residues in peptides is much greater than in the amino acid itself and 5-10 times that for exchange of the H-5 protons. This suggests that the method can be used to label tryptophyl residues in proteins rapidly and specifically.

Original languageEnglish
Pages (from-to)103-111
Number of pages9
JournalMolecular and Cellular Biochemistry
Volume12
Issue number2
DOIs
Publication statusPublished - Aug 1976
Externally publishedYes

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