Development of a multifunctional benzophenone linker for peptide stapling and photoaffinity labeling

Abstract

Photoaffinity labelling is a useful method for studying how proteins interact with ligands and biomolecules, and can help identify and characterise new targets for the development of new therapeutics. We present the design and synthesis of a novel multifunctional benzophenone linker, which serves as both a photocrosslinking motif and a peptide stapling reagent. Using a double-click stapling methodology, we attach the benzophenone to the peptide via the staple linker, rather than modifying the peptide sequence with a photocrosslinking amino acid. Applied to a p53-derived peptide, the resulting photoreactive stapled peptide is able to preferentially crosslink with MDM2 in the presence of competing protein. This multifunctional linker also features an extra alkyne handle for downstream applications such as pull-down assays, and can be used to investigate the target selectivity of stapled peptides.