Disulfide rich peptides are unique in both their incredibly high cysteine content, but also in the stability imbued by the multiple disulfide bonds. These peptides, stable under extreme conditions that would either denature or degrade a similar linear peptide, make disulfide rich peptides attractive as both therapeutics or as scaffolds upon which to construct non-native functionality. Synthesizing these compounds, however, still remains a challenge.
I have discussed previously strategies that enable on-resin chemistry via orthogonal protecting groups. These groups can be removed under mildly acidic, metal catalyzed, or even oxidizing conditions. In today’s post, I’ll demonstrate the utility of using disulfide shuffling as a cysteine protection strategy.