Unraveling the mystery of how catalytic organic polymers first arose on a prebiotic Earth will hold the key to understanding the origin of life. Researchers at Tohoku University have recently discovered possible environments for the production of catalytic organic polymers. To make this discovery, they evaporated an amino acid solution containing boronic acid and found that boronic acid promoted peptide production in both neutral and acidic environments. Under neutral conditions, the longest polypeptide formed in the experiment was a 39-mer long glycine polypeptide.
Previous studies have shown that highly alkaline evaporative environments are sites of ancient protein synthesis, producing glycine polypeptides up to 20 monomers long. Neutral conditions are considered the worst case for peptide synthesis.
Boron-rich ancient coastal regions can catalyze the polymerization of amino acids.
Boron-containing minerals have been found in abundance in some of the oldest sedimentary rocks ever found on Earth, dating back 3.8 billion years. These findings suggest that the coastal regions of boronic acid-rich ancient small continents and islands spontaneously assembled amino acids into peptides and proproteins.
Associate Professor Furukawa Yoshihiro of Tohoku University said: "The formation of polypeptides in a neutral environment is of great significance to the chemical evolution of the origin of life."
RNA is quite stable under neutral conditions, but extremely unstable under alkaline conditions. Boron is known to assist in many steps of abiotic ribonucleotide synthesis.
"The boron-rich neutral evaporative environment was an ideal place for the formation and interaction of two fundamental polymers on pre-biological Earths," Furukawa said.
The research group is currently investigating which amino acids are added to the pro-peptide in this context.
