Effects of Activation Barriers on Quenching to Stabilize Prebiotic Chemical Systems
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 effici...
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MDPI AG
2024-01-01
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| Series: | Life |
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| Online Access: | https://www.mdpi.com/2075-1729/14/1/116 |
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| author | Qianyi Sheng Ben Fredrick Intoy J. W. Halley |
| author_facet | Qianyi Sheng Ben Fredrick Intoy J. W. Halley |
| author_sort | Qianyi Sheng |
| collection | DOAJ |
| description | 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 <i>p</i> in our previous models. Within the model, a characteristic temperature <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>T</mi><mi>c</mi></msub></semantics></math></inline-formula> emerges such that if the temperature of the hot stage is above <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>T</mi><mi>c</mi></msub></semantics></math></inline-formula> 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. |
| first_indexed | 2024-03-08T10:44:40Z |
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| language | English |
| last_indexed | 2024-03-08T10:44:40Z |
| publishDate | 2024-01-01 |
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| series | Life |
| spelling | doaj.art-c53b34e315844b05ae5f1184351c1adf2024-01-26T17:21:04ZengMDPI AGLife2075-17292024-01-0114111610.3390/life14010116Effects of Activation Barriers on Quenching to Stabilize Prebiotic Chemical SystemsQianyi Sheng0Ben Fredrick Intoy1J. W. Halley2School of Physics and Astronomy, University of Minnesota-Twin Cities, Minneapolis, MN 55455, USASchool of Physics and Astronomy, University of Minnesota-Twin Cities, Minneapolis, MN 55455, USASchool of Physics and Astronomy, University of Minnesota-Twin Cities, Minneapolis, MN 55455, USAWe 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 <i>p</i> in our previous models. Within the model, a characteristic temperature <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>T</mi><mi>c</mi></msub></semantics></math></inline-formula> emerges such that if the temperature of the hot stage is above <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>T</mi><mi>c</mi></msub></semantics></math></inline-formula> 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.https://www.mdpi.com/2075-1729/14/1/116astrobiologyprebiotic chemistryorigin of lifehydrothermal systemsquenching |
| spellingShingle | Qianyi Sheng Ben Fredrick Intoy J. W. Halley Effects of Activation Barriers on Quenching to Stabilize Prebiotic Chemical Systems Life astrobiology prebiotic chemistry origin of life hydrothermal systems quenching |
| title | Effects of Activation Barriers on Quenching to Stabilize Prebiotic Chemical Systems |
| title_full | Effects of Activation Barriers on Quenching to Stabilize Prebiotic Chemical Systems |
| title_fullStr | Effects of Activation Barriers on Quenching to Stabilize Prebiotic Chemical Systems |
| title_full_unstemmed | Effects of Activation Barriers on Quenching to Stabilize Prebiotic Chemical Systems |
| title_short | Effects of Activation Barriers on Quenching to Stabilize Prebiotic Chemical Systems |
| title_sort | effects of activation barriers on quenching to stabilize prebiotic chemical systems |
| topic | astrobiology prebiotic chemistry origin of life hydrothermal systems quenching |
| url | https://www.mdpi.com/2075-1729/14/1/116 |
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