Proline Might Have Been the First Amino Acid in the Primitive Genetic Code
Reina Komatsu, Risa Sawada, Takuya Umehara, Koji Tamura
Journal of Molecular Evolution
Stereochemical assignment of amino acids and corresponding codons or anticodons has not been successful so far. Here, we focused on proline and GGG (anticodon of tRNAPro) and investigated their mutual interaction. Circular dichroism spectroscopy revealed that guanosine nucleotides (GG, GGG) formed G-quartet structures. The structures were destroyed by adding high concentrations of proline. We propose that the possibility of the reversible proline/G-quartet interaction could have contributed to the specific assignment of proline on GGG and that this coding could have been the first in the genetic code.
Circular dichroism, Ligand binding, Biochemistry