Heteropolynucleotides as templates for non-enzymatic polymerizations

Area of Science:

• Prebiotic chemistry
• Origin of life studies
• Nucleotide chemistry

Background:

• Understanding the prebiotic synthesis of polynucleotides is crucial for origin of life research.
• Activated nucleotides are key building blocks for early RNA or DNA polymers.

Purpose of the Study:

• To investigate condensation reactions of various activated nucleotides (ImpU, ImpT, ImpC, ImpA, ImpG, ImpUpG, ImpCpA) using polynucleotide templates.
• To assess the template effect and product linkage in prebiotic polymerization.

Main Methods:

• Studied condensation reactions with activated nucleotide donors and homo- and hetero-polynucleotide templates.
• Analyzed template-directed incorporation of nucleotides.
• Quantified the percentage of natural 3'-5' linkages in the synthesized products.

Main Results:

• ImpU and ImpT showed no template effect; ImpC, ImpA, ImpG, ImpUpG, and ImpCpA exhibited template-directed condensations with varying efficiencies.
• Pyrimidine nucleotides were preferentially incorporated into short oligomers containing purine nucleotides.
• Product linkage varied significantly, with natural 3'-5' linkages ranging from <10% to 70%.
• Wobble-pairing effectively promoted condensations, suggesting frequent transition mutations in prebiotic replication.

Conclusions:

• Pyrimidine nucleotides likely incorporated into early polymers as components of short, purine-containing oligomers.
• The efficiency and linkage of prebiotic polymer formation are substrate-dependent.
• Wobble-pairing played a significant role in early polynucleotide replication, potentially leading to high mutation rates.