Simple and inexpensive incorporation of 19F-Tryptophan for protein NMR spectroscopy

Fluorine-containing amino acids are valuable probes for the biophysical characterization of proteins. Current methods for F-19-labeled protein production involve time-consuming genetic manipulation, compromised expression systems and expensive reagents. We show that Escherichia coli BL21, the workhorse of protein production, can utilise fluoroindole for the biosynthesis of proteins containing F-19-tryptophan.