Formation of peptide bonds from metastable versus crystalline phase: implications for the origin of life

Abstract

Formation of peptide bonds was attempted by thermal activation of dry amino acids from
aqueous solution that simulated prebiotic evaporative environments. The evaporation trend of amino
acids solutions shows a bifurcation and can lead to either a crystalline phase (near equilibrium) or a
metastable non-crystalline phase (far from equilibrium). Only amino acids in this metastable phase
are able to form peptide bonds by thermal activation at temperatures that are generated by solar
radiation today. We suggest that this metastable phase is the ideal initial material to trigger amino
acid assemblage with protein-like structure because provide the driving force (supersaturation) for
an intense interaction between monomers of different amino acids and allows activation of these
monomers in plausible prebiotic conditions.