A new strategy for selective protein modification

We report a versatile new method for the selective modification of proteins and peptides at their N-terminus using enzymatic activation of simple fatty acids.

In this study, published in Angewandte Chemie International Edition, researchers from the Tate group and collaborators developed a biomimetic approach termed enzymatic reagent activation (ERA). This method uses the adenylation domain of a carboxylic acid reductase enzyme from Segniliparus rugosus (CARsr-A) to activate carboxylic acids in situ, generating reactive intermediates that selectively modify the N-terminal α-amine of peptides and proteins without requiring pre-functionalised reagents.

The ERA strategy showed high selectivity for the N-terminus over lysine side chains across a range of biologically relevant substrates, including therapeutic peptides such as liraglutide, glucagon and insulin. The method is compatible with a broad range of fatty acids, including functionalised substrates such as azides and dicarboxylic acids, enabling straightforward incorporation of bioorthogonal handles for downstream applications.

Importantly, the approach can also be extended to larger biomolecules, with successful application to antibody modification. This highlights its potential for the development of antibody–drug conjugates and other bioconjugates, without the need for genetic engineering or complex reagent synthesis.

By enabling one-pot, selective N-terminal modification from readily available building blocks, this work provides a powerful addition to the bioconjugation toolbox, with broad applications in chemical biology, biotechnology and therapeutic development.

Congratulations to all researchers involved in this work! This project was funded by the EPSRC, BBSRC, and AstraZeneca.