Reversible Cystine Disulfide Scaffolding Enables Carbonyl Sulfide-Mediated Intramolecular Peptide Bond Formation via Cyclocystine: Implications for Prebiotic Chemistry.
Treatment of cystine (the disulfide-linked dimer of cysteine) with carbonyl sulfide (COS) results in the formation of cyclocystine, which upon reduction yields the Cys-Cys dipeptide. These findings demonstrate a role for the cystine disulfide bond as a molecular scaffold that favors intramolecular peptide bond formatio...