Lab. Life Sci. for Extremophiles

One of the challenging topics to be solved regarding the "origin of life" is how proteins emerged in the RNA world. The basic structural units of existing proteins are 20 types of L-amino acids (standard amino acids), which are specified by the standard genetic code. In most cases, living organisms either take these amino acids from the environment or synthesize them within cells through biosynthetic pathways, and use them for protein synthesis. However, in primitive protein synthesis before the establishment of amino acid biosynthetic pathways in organisms, only amino acids that were synthesized abiotically in the primitive environment (synthesized on the primitive Earth or brought to Earth from space) would have been used. It is not certain whether all 20 amino acids specified by the genetic code existed on the primitive Earth, and some studies suggest that only around 10 types of amino acids, often referred to as "prebiotic amino acids," were present on the primitive Earth.
　In our laboratory, we are conducting experiments to determine the minimum set of amino acids required to create a functional protein, and whether this "minimal amino acid set" aligns with the "prebiotic amino acids" that are thought to have been present on early Earth. We are testing this by reconstructing proteins using only a reduced set of amino acids.