Mechanochemical Prebiotic Peptide Bond Formation

The presence of amino acids on the prebiotic Earth, either stemming from endogenous chemical routes or delivered by meteorites, is consensually accepted. In contrast, prebiotically plausible pathways to achieve peptides from inactivated amino acids are still unclear since most oligomerization approaches rely on thermodynamically disfavored reactions in solution. Here, we show that the combination of prebiotically plausible minerals and mechanochemical activation enables the oligomerization of glycine at ambient temperature in the absence of water. Raising the reaction temperature increases the degree of oligomerization concomitantly with the formation of a commonly unwanted cyclic glycine dimer (DKP). However, we show here that DKP is a productive intermediate in the mechanochemical oligomerization of glycine. The findings of this research show that mechanochemical peptide bond formation is a dynamic process that provides alternative routes towards oligopeptides and establishes new synthetic approaches for prebiotic chemistry.