Understanding how catalytic organic polymers appeared on Earth before life began is an important question that needs to be answered to gain insights into the origin of life.
Scientists at Tohoku University have discovered a possible environment where catalytic organic polymers may have formed. They conducted experiments with solutions of amino acids and boric acid that were dried down and found that boric acid helped to catalyze the synthesis of polypeptides under both neutral and acidic conditions. The experiments resulted in the formation of the longest polypeptides, consisting of 39 monomers, under a neutral condition.
Earlier research has proposed that the formation of ancient proteins occurred in highly alkaline evaporative environments, where up to 20 monomer-long glycine peptides were produced. On the other hand, it was believed that neutral conditions were unfavorable for peptide synthesis.
Scientists have found boron-containing minerals in some of the oldest sedimentary rocks on Earth, dating back 3.8 billion years. These rocks suggest that boric acid was present in coastal areas of ancient small continents and islands, which could have spontaneously assembled amino acids, leading to the formation of polypeptides and proto-proteins.
Yoshihiro Furukawa, who is an associate professor at Tohoku University and the lead author of the study, states that the creation of polypeptides under neutral conditions is significant for the chemical evolution of the origin of life.
RNA molecules can easily break down in alkaline conditions. But boron has been found to be helpful in creating RNA building blocks even in such conditions.
According to Furukawa, environments on prebiotic Earth that were rich in boron and had a neutral pH were perfect for the formation and interaction of two important polymers.
This research group is now investigating which amino acids are incorporated in the proto-peptides in this environment.
Details of their research were published in the journal Communications Chemistry on May 11, 2023.
