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Lipid-assisted Synthesis of Nucleic Acids under Prebiotically Plausible Wet-dry Cycling Conditions

Presentation #108.02 in the session Astrobiology and Origins of Life (Oral Presentation)

Published onOct 23, 2023
Lipid-assisted Synthesis of Nucleic Acids under Prebiotically Plausible Wet-dry Cycling Conditions

A critical step in the emergence of cellular life is non-enzymatic polymerisation of monomers such as amino acids and nucleotides, followed by encapsulation within membranous compartments to form protocell populations. Freshwater hot spring environments on subaerial volcanic land masses are particularly conducive to this process because cycles of hydration and dehydration concentrate potential reactants and provide chemical free energy to drive condensation reactions.

We are investigating the lipid-assisted synthesis of DNA and RNA polymers from non-activated monomers in laboratory simulations of prebiotically plausible wet-dry cycling conditions [1]. Our primary goal is to determine which conditions are optimal in promoting polymerization of mononucleotides. We are also investigating how amphiphilic molecules interact with nucleotides and their polymers to assemble into protocellular systems.

A novel feature of our approach is the use of nanopore sequencing to monitor the synthesis of polymers and their base sequences. Preliminary results demonstrate that wet-dry cycles drive condensation reactions of mononucleotides with DNA and RNA oligomers as products. The polymer products are recognized by enzymes such as alkaline phosphatase and T4 kinase used to end-label RNA with radioactive phosphate. The presence of amphiphilic molecules promotes polymerization [2] and suppresses depurination reactions [3]. Encapsulation of the oligomers in membranous compartments provides a pathway for the emergence of protocell populations [4].

These results provide insights into the process by which critical steps in the origin of cellular life may have occurred and have significant implications for geophysical sites that are most conducive for the emergence of complex cellular systems [5].

References:

[1] D. Deamer, F. Cary, and B. Damer, “Urability: A Property of Planetary Bodies That Can Support an Origin of Life,” Astrobiology, 22, 2022.

[2] S. Rajamani, A. Vlassov, S. Benner, A. Coombs, F. Olasagasti, and D. Deamer, “Lipid-assisted synthesis of RNA-like polymers from mononucleotides,” Orig. Life Evol. Biosph., 38, 2008.

[3] R. Lorig-Roach and D. Deamer, “Condensation and Decomposition of Nucleotides in Simulated Hydrothermal Fields,” pp. 21–30, 2018.

[4] D. W. Deamer and G. L. Barchfeld, “Encapsulation of macromolecules by lipid vesicles under simulated prebiotic conditions,” J. Mol. Evol., 18, 1982.

[5] D. Deamer, “Origins of Life Research: The Conundrum between Laboratory and Field Simulations of Messy Environments,” Life, 12, 2022.

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