Effects of Activation Barriers on Quenching to Stabilize Prebiotic Chemical Systems

Qianyi Sheng, Ben Frederick M Intoy, J. W. Halley

Research output: Contribution to journalArticlepeer-review

Abstract

We have previously shown in model studies that rapid quenches of systems of monomers interacting to form polymer chains can fix nonequilibrium chemistries with some lifelike properties. We suggested that such quenching processes might have occurred at very high rates on early Earth, giving an efficient mechanism for natural sorting through enormous numbers of nonequilibrium chemistries from which the most lifelike ones could be naturally selected. However, the model used for these studies did not take account of activation barriers to polymer scission (peptide bond hydrolysis in the case of proteins). Such barriers are known to exist and are expected to enhance the quenching effect. Here, we introduce a modified model which takes activation barriers into account and we compare the results to data from experiments on quenched systems of amino acids. We find that the model results turn out to be sensitive to the width of the distribution of barrier heights but quite insensitive to its average value. The results of the new model are in significantly better agreement with the experiments than those found using our previous model. The new parametrization of the model only requires one new parameter and the parametrization is more physical than the previous one, providing a chemical interpretation of the parameter p in our previous models. Within the model, a characteristic temperature (Formula presented.) emerges such that if the temperature of the hot stage is above (Formula presented.) and the temperature of the cold stage is below it, then the ‘freezing out’, in a quench, of a disequilibrium ensemble of long polymers is expected. We discuss the possible relevance of this to models of the origin of life in emissions from deep ocean rifts.

Original languageEnglish (US)
Article number116
JournalLife
Volume14
Issue number1
DOIs
StatePublished - Jan 2024

Bibliographical note

Publisher Copyright:
© 2024 by the authors.

Keywords

  • astrobiology
  • hydrothermal systems
  • origin of life
  • prebiotic chemistry
  • quenching

PubMed: MeSH publication types

  • Journal Article

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