Scientists at Tohoku University have made a significant discovery that sheds light on the emergence of catalytic organic polymers on prebiotic Earth. Their research, published in the journal Communications Chemistry on May 11, 2023, reveals that boric acid catalyzes polypeptide synthesis in amino acid solutions under neutral and acidic conditions. This finding challenges the previously held belief that highly alkaline environments were necessary for ancient protein synthesis.
The team dried amino acid solutions containing boric acid and found that the longest peptides formed were 39 monomer-long glycine polypeptides under neutral conditions. These peptides were formed in boron-rich evaporative environments, which were abundant in ancient coastal areas.
Boron-containing minerals have been discovered in some of the oldest sedimentary-origin rocks on Earth, dating back 3.8 billion years. These findings suggest that boric acid played a crucial role in the spontaneous assembly of amino acids, forming polypeptides and proto-proteins.
Lead author Yoshihiro Furukawa, an associate professor at Tohoku University, believes that the formation of polypeptides in neutral environments has important implications for the chemical evolution of the origin of life. While RNAs are rather stable under neutral conditions, they are highly unstable under alkaline conditions. Boron has been known to facilitate many steps in abiotic ribonucleotide synthesis, making it an ideal candidate for the formation and interaction of essential polymers on prebiotic Earth.
The researchers are now investigating which amino acids are incorporated into proto-peptides in this environment, further unlocking key understandings in the origin of life.
Source: Tohoku University