ΔAlaAz cleavable linkers: efficient peptide cleavage in the presence of aromatic thiols and air oxygen

Selective disassembly of multifunctional molecules through the use of cleavable linkers is central to many aspects of chemical biology, biochemistry, and pharmaceutical science. Ideally, cleavable linkers are structurally small and chemically stable on their own but fragment rapidly in the presence of a specific trigger without damaging the rest of the molecule. Here, we report the discovery of the facile oxidative cleavage of 2-(1-amidovinyl)azole-containing peptides (ΔAlaAz; Az: thiazole or oxazole) in the presence of aromatic thiols and air oxygen under ambient conditions. The reaction leads to quantitative peptide cleavage in minutes (<5 min for some substrates) in aqueous buffers at room temperature. We demonstrate that the ΔAlaAz cleavable linkers can be utilized to (i) linearize complex cyclic peptides, (ii) aid the structure determination of ΔAlaAz-containing natural products, and (iii) facilitate the isolation of peptides from cell lysates. Altogether, our work adds an efficient method to the toolbox of cleavable linkers in chemical biology.