Introducing Azobenzenes as Solid Phase Peptide Synthesis Linkers

Abstract

Orthogonally cleavable linkers are essential tools in solid-phase peptide synthesis (SPPS). We present a fluorogenic Coumarin-Loaded Azobenzene (COLAZ) linker for SPPS, which offers base and acid stability and a mild reductive cleavage. We synthesise model peptide WHISKEY with an integrated coumarin label using COLAZ resin and demonstrate that COLAZ and Rink linker technologies may be combined to produce peptides with a latent fluorophore. The biological compatibility of the COLAZ unit is demonstrated in vitro by tracking its glutathione-induced cleavage and in live cells by imaging the uptake of an R10 cell-penetrating peptide using two photon fluorescence (TPF) and stimulated Raman scattering (SRS).