Leucyl/phenylalanyl(L/F)‐tRNA‐protein transferase‐mediated aminoacyl transfer of a nonnatural amino acid to the N‐terminus of peptides and proteins and subsequent functionalization by bioorthogonal reactions

Abstract

We report here a new strategy for derivatizing peptides and proteins at the N‐terminus. To achieve this, a nonnatural amino acid was charged onto a tRNA and then enzymatically transferred to a lysine (Lys) unit at the N‐terminus of a peptide or a protein by using L/F‐tRNA‐protein transferase. By using the chemoenzymatic technique, β‐(2‐quinolyl)‐L‐alanine, p‐azido‐L‐phenylalanine, and p‐acetyl‐L‐phenylalanine were introduced to the N‐terminus. The latter two nonnatural amino acids possess bioorthogonal functional groups to which artificial tags can be introduced. Actually, a biotin tag was coupled to the bioorthogonal ketone group of acetylphenylalanine at the N‐terminus of a peptide. N‐terminal‐specific biotinylation and fluorescence derivatization of the bioorthogonal azido‐containing protein or peptide was also carried out based on a [3 + 2] cycloaddition. The enzymatic transfer of a nonnatural amino acid to the N‐terminus of target peptides or proteins was also successfully achieved in the presence of other peptides or crude protein mixtures. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 88: 263–271, 2007. This article was originally published online as an accepted preprint. The ‘Published Online’ date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

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