Proline might have been the first amino acid in the primitive genetic code

Area of Science:

• Biochemistry
• Origin of life studies
• Molecular biology

Background:

• The stereochemical assignment of amino acids to their corresponding codons or anticodons remains a significant challenge in understanding the genetic code's origin.
• Investigating specific amino acid-nucleic acid interactions offers insights into early coding mechanisms.

Discussion:

• Guanosine nucleotides (GG, GGG) form stable G-quartet structures, as evidenced by circular dichroism spectroscopy.
• Proline was found to disrupt these G-quartet structures at high concentrations, indicating a direct interaction.

Key Insights:

• A reversible interaction between proline and G-quartet structures is proposed.
• This interaction may have played a crucial role in the specific assignment of proline to the GGG anticodon.
• This proline-GGG interaction is hypothesized to be one of the earliest coding events in the genetic code.

Outlook:

• Further research can explore similar interactions for other amino acids and codons.
• Investigating the physical-chemical conditions that favor such reversible interactions is essential.
• This study provides a potential model for the prebiotic selection of amino acid-codon pairings.