Copying of Mixed-Sequence RNA Templates inside Model Protocells

Area of Science:

• Origin of life studies
• Prebiotic chemistry
• Protocell research

Background:

• Chemical RNA replication within fatty acid vesicles is a plausible step in abiogenesis.
• Protocells could have imported nucleotides and short oligomers for RNA replication.
• Previous work showed helper RNA oligomers enable nonenzymatic RNA copying in solution.

Purpose of the Study:

• To investigate methods for enhancing RNA oligomer permeability into fatty acid vesicles.
• To determine if specific conditions support nonenzymatic RNA replication within protocells.
• To advance the development of a protocell capable of Darwinian evolution.

Main Methods:

• Utilized citrate-chelated magnesium (Mg2+) as a catalyst for nonenzymatic primer extension.
• Assessed the effect of Mg2+ on fatty acid membrane permeability to RNA oligomers of varying lengths.
• Investigated the impact of temperature on selective membrane permeability for short oligonucleotides.

Main Results:

• Citrate-chelated Mg2+ enhanced membrane permeability to RNA oligomers up to tetramers without vesicle disruption.
• Selective permeability for short oligonucleotides was further improved by increasing temperature.
• Achieved nonenzymatic RNA copying of templates with all four nucleotides inside vesicles.

Conclusions:

• Magnesium-enhanced membrane permeability is crucial for encapsulating RNA precursors in protocells.
• Controlled permeability allows for the nonenzymatic replication of genetic material within early cellular structures.
• This research provides a significant step towards constructing a protocell capable of evolutionary processes.