Non-enzymatic template-directed synthesis on RNA random copolymers. Poly(C,A) templates

Area of Science:

• Biochemistry
• Origin of Life Studies
• Polymer Chemistry

Background:

• Investigating the prebiotic synthesis of oligonucleotides is crucial for understanding the origin of life.
• RNA templates play a key role in directing the formation of specific oligonucleotide sequences.

Purpose of the Study:

• To evaluate the efficacy of poly(C,A) random copolymer templates in directing the oligomerization of 2-methylimidazolide monomers (2-MeImpG and 2-MeImpU).
• To assess the suitability of adenine-rich RNA sequences for chemical self-replication.

Main Methods:

• Oligomerization reactions using poly(C,A) templates with 2-MeImpG and 2-MeImpU.
• Analysis of oligomeric products using high-pressure liquid chromatography (HPLC) on an RPC-5 column.
• Characterization of oligomers based on chain length, base composition, and linkage isomerism.

Main Results:

• Poly(C,A) templates yielded a variety of oligo(G,U)s, but with lower efficiency compared to poly(C,U) or poly(C,G) templates.
• Monomer incorporation efficiency was lower for 2-MeImpU than 2-MeImpG, and not improved by increasing 2-MeImpU concentration.
• Oligomers up to the 13-mer, including Gn, Gn-1U, and Gn-2U2 compositions, were identified.

Conclusions:

• RNA sequences with consecutive adenine residues are likely unsuitable for efficient chemical self-replication.
• Template-directed oligomerization efficiency is dependent on both template sequence and monomer identity.