Improved synthetic methods for the selective deuteration of aromatic amino acids : applications of selective protonation towards the identification of protein folding intermediates through nuclear magnetic resonance

摘要: Abstract In this report we describe several novel methods for the preparation of selectively deuterated aromatic amino acids. New syntheses [2,3,5,6- 2 H 4 ]phenylalanine and [2,4,6,7- ]tryptophan, as well improved catalytic exchange ]tyrosine [2,3,4,5,6- 5 are presented. Isotopic substitution levels all compounds generally found to be greater than 95%. Biosynthetic incorporation these acids is also shown possible with little or no evidence isotopic scrambling. The products from new syntheses, in combination other acids, permit group-specific ‘single-proton’ labelling proteins. This highly-efficient very cost-effective method selective protonation produce greatly simplified 1 H-NMR spectra region utility approach editing demonstrated identifica tion a transient folding intermediate Escherichia coli thioredoxin which undetectable by standard 2-D NMR techniques.