Wet-dry cycles cause nucleic acid monomers to polymerize into long chains

Area of Science:

• Origin of life studies
• Prebiotic chemistry
• Polymerization reactions

Background:

• Monomer oligomerization typically requires initiators like thermolysis or photolysis.
• Dehydration at high temperatures can synthesize ester and peptide bonds, but usually in dry conditions.

Purpose of the Study:

• To present a novel method for initiating acid-catalyzed polymerization at the water surface.
• To investigate the oligomerization of nucleic acids via wet-dry cycles relevant to early Earth conditions.

Main Methods:

• Acid-catalyzed polymerization initiated at the surface of water films/droplets during wet-dry cycles.
• Mass spectrometry, nanopore sequencing, enzyme digestion, 31P NMR, and Fourier transform infrared spectroscopy were used for analysis.

Main Results:

• Wet-dry cycles successfully linked mononucleotides, forming phosphodiester bonds and producing long-chain nucleic acid oligomers.
• Uridine monophosphate oligomers up to 53 nucleotides were observed, with notable abundance at 35 and 43 nt.
• Long-chain oligomers were formed for thymidine monophosphate, adenosine monophosphate, and deoxyadenosine monophosphate.

Conclusions:

• Nucleic acid polymerization can be initiated at the water surface during wet-dry cycles, mimicking potential early Earth conditions.
• This process suggests a plausible mechanism for the formation of essential prebiotic nucleic acid polymers.
• The findings support the hypothesis of a steady-state synthesis and hydrolysis of nucleic acid oligomers on early Earth.