The photophysical probe, 7-azatryptophan, in synthetic peptides

7-Azatryptophan is proposed as an alternative to tryptophan as a photophysical probe in the study of protein structure and dynamics. Not only are the spectral characteristics of 7-azatryptophan easily distinguishable from those of tryptophan, but this nonnatural amino acid is shown to be amenablc to incorporation into peptides. We present the first synthesis and purification of a synthetic peptide containing 7-azatryptophan, NAc-Pro-7-azatryptophan-Asn-NH2, which is shown to be a competitive inhibitor of α-chymotrysin.