PUB - Publikationen an der Universität Bielefeld

Bio‐orthogonal reactions for modification of proteins and unprotected peptides are of high value in chemical biology. The combination of enzymatic halogenation with transition metal catalysed cross‐coupling provides a feasible approach for modification of proteins and unprotected peptides. Using a semi‐rational protein engineering approach, variants of the tryptophan 6‐halogenase Thal were identified that enable efficient bromination of peptides with a C‐terminal tryptophan residue. The substrate scope was explored using di‐, tri‐, and tetrapeptide arrays leading to the identification of an optimized peptide tag we named BromoTrp tag. This tag was introduced into three model proteins. Preparative scale post‐translational bromination was possible with only a single cultivation and purification step using the brominating E. coli coexpression systemBrocoli. Pd‐catalysed Suzuki‐Miyaura cross‐coupling of the bromoarene was achieved using Pd nanoparticle catalysts at 37 °C, highlighting the rich potential of this strategy for bioorthogonal functionalization and conjugation.