A continuous reaction network that produces RNA precursors

Area of Science:

• Astrobiology and Origin of Life Research
• Prebiotic Chemistry and Molecular Evolution

Background:

• Continuous reaction networks model chemical evolution, previously demonstrated for amino acids, hydroxy acids, and sugars.
• Synthesizing ribonucleotides via continuous networks is challenging, despite known step-by-step protocols.

Purpose of the Study:

• To demonstrate the synthesis of key prebiotic RNA precursors in a continuous reaction network.
• To model the spontaneous formation of essential molecules from simple reagents under plausible early Earth conditions.

Main Methods:

• A continuous reaction network was initiated using an aqueous mixture of NaCl, NH4Cl, phosphate, and hydrogen cyanide (HCN).
• The network was driven by a combination of gamma (γ) radiolysis and a dry-down process.
• No additional reagents or timed additions were required after initial setup.

Main Results:

• Gamma radiolysis produced a complex organic mixture, including glyceronitrile and cyanamide.
• Subsequent dry-down generated free glycolaldehyde, which reacted with cyanamide/NH3.
• The reaction yielded 2-aminooxazole and 2-aminoimidazole, crucial for prebiotic RNA synthesis.

Conclusions:

• This continuous reaction network successfully generated key molecules for prebiotic RNA synthesis.
• The study provides a model for how complex organic precursors can arise spontaneously from simple starting materials.
• Demonstrates a plausible pathway for the origin of essential biomolecules under early Earth conditions.