Prebiotic synthesis of cysteine peptides that catalyze peptide ligation in neutral water
Callum S. Foden, Saidul Islam, Christian Fernández‐García, Leonardo Maugeri, Tom D. Sheppard, Matthew W. Powner
Abstract
Cysteine as peptide precursor and catalyst Among amino acids, cysteine is highly reactive as a nucleophile, metal ligand, and participant in redox and radical reactions. These properties make cysteine attractive as a component of prebiotic chemistry, but traditional Strecker synthesis of α-aminonitriles, which can serve as peptide precursors, cannot produce free cysteine. Foden et al. found that a simple acylation of the free amine prevented degradation of cysteine nitrile and enabled synthesis of this cysteine precursor from acetyl dehydroalanine nitrile and a sulfide donor (see the Perspective by Muchowska and Moran). When combined with other proteinogenic α-aminonitriles, acetylcysteine or derivative thiols catalyzed efficient peptide ligation in water. These results highlight how prebiotic synthesis of precursors can also generate function by creating a catalyst for polymerization. Science , this issue p. 865 ; see also p. 767