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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

A convenient selective synthesis of 2′,3′-di-O-acetyl-nucleotide-5′-phosphates, 2′,3′-di-O-acetyl-nucleotide-5′-triphosphates and 2′,3′,5′-tri-O-acetyl-nucleosides in water has been developed. Furthermore, a long-chain selective glycerol-3-phosphocholine diacylation is elucidated. These reactions are environmentally benign, rapid, high yielding, and the products are readily purified. Importantly, this reaction may indicate a prebiotically plausible reaction pathway for the selective acylation of key metabolites to facilitate their incorporation into protometabolism.

RNA is essential to all life on Earth and is the leading candidate for the first biopolymer of life. Aminooxazolines have recently emerged as key prebiotic ribonucleotide precursors, and here we develop a novel strategy for aminooxazoline-5′-phosphate synthesis in water from prebiotic feedstocks. Oxidation of acrolein delivers glycidaldehyde (90%), which directs a regioselective phosphorylation in water and specifically affords 5′-phosphorylated nucleotide precursors in upto 36% yield. We also demonstrated a generational link between proteinogenic amino acids (Met, Glu, Gln) and nucleotide synthesis.