The Role of the CuCl Active Complex in the Stereoselectivity of the Salt-Induced Peptide Formation Reaction: Insights from Density Functional Theory Calculations
The salt-induced peptide formation (SIPF) reaction is a prebiotically plausible mechanism for the spontaneous polymerization of amino acids into peptides on early Earth. Experimental investigations of the SIPF reaction have found that in certain conditions, the <span style="font-variant: sma...
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MDPI AG
2023-08-01
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| Series: | Life |
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| Online Access: | https://www.mdpi.com/2075-1729/13/9/1796 |
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| author | Allison C. Fox Jason D. Boettger Eve L. Berger Aaron S. Burton |
| author_facet | Allison C. Fox Jason D. Boettger Eve L. Berger Aaron S. Burton |
| author_sort | Allison C. Fox |
| collection | DOAJ |
| description | The salt-induced peptide formation (SIPF) reaction is a prebiotically plausible mechanism for the spontaneous polymerization of amino acids into peptides on early Earth. Experimental investigations of the SIPF reaction have found that in certain conditions, the <span style="font-variant: small-caps;">l</span> enantiomer is more reactive than the <span style="font-variant: small-caps;">d</span> enantiomer, indicating its potential role in the rise of biohomochirality. Previous work hypothesized that the distortion of the CuCl active complex toward a tetrahedral-like structure increases the central chirality on the Cu ion, which amplifies the inherent parity-violating energy differences between <span style="font-variant: small-caps;">l-</span> and <span style="font-variant: small-caps;">d</span>-amino acid enantiomers, leading to stereoselectivity. Computational evaluations of this theory have been limited to the protonated–neutral <span style="font-variant: small-caps;">l + l</span> forms of the CuCl active complex. Here, density functional theory methods were used to compare the energies and geometries of the homochiral (<span style="font-variant: small-caps;">l + l </span>and<span style="font-variant: small-caps;"> d + d)</span> and heterochiral <span style="font-variant: small-caps;">(l + d)</span> CuCl–amino acid complexes for both the positive–neutral and neutral–neutral forms for alanine, valine, and proline. Significant energy differences were not observed between different chiral active complexes (i.e., <span style="font-variant: small-caps;">d + d, l + l </span>vs.<span style="font-variant: small-caps;"> l + d),</span> and the distortions of active complexes between stereoselective systems and non-selective systems were not consistent, indicating that the geometry of the active complex is not the primary driver of the observed stereoselectivity of the SIPF reaction. |
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| language | English |
| last_indexed | 2024-03-10T22:32:40Z |
| publishDate | 2023-08-01 |
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| series | Life |
| spelling | doaj.art-1873638d0cdb4bbcada8dd4d7f7673cc2023-11-19T11:36:25ZengMDPI AGLife2075-17292023-08-01139179610.3390/life13091796The Role of the CuCl Active Complex in the Stereoselectivity of the Salt-Induced Peptide Formation Reaction: Insights from Density Functional Theory CalculationsAllison C. Fox0Jason D. Boettger1Eve L. Berger2Aaron S. Burton3NASA Postdoctoral Program, NASA Johnson Space Center, Houston, TX 77058, USADepartment of Earth, Environmental and Resource Sciences, University of Texas at El Paso, El Paso, TX 79968, USAAstromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX 77058, USAAstromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX 77058, USAThe salt-induced peptide formation (SIPF) reaction is a prebiotically plausible mechanism for the spontaneous polymerization of amino acids into peptides on early Earth. Experimental investigations of the SIPF reaction have found that in certain conditions, the <span style="font-variant: small-caps;">l</span> enantiomer is more reactive than the <span style="font-variant: small-caps;">d</span> enantiomer, indicating its potential role in the rise of biohomochirality. Previous work hypothesized that the distortion of the CuCl active complex toward a tetrahedral-like structure increases the central chirality on the Cu ion, which amplifies the inherent parity-violating energy differences between <span style="font-variant: small-caps;">l-</span> and <span style="font-variant: small-caps;">d</span>-amino acid enantiomers, leading to stereoselectivity. Computational evaluations of this theory have been limited to the protonated–neutral <span style="font-variant: small-caps;">l + l</span> forms of the CuCl active complex. Here, density functional theory methods were used to compare the energies and geometries of the homochiral (<span style="font-variant: small-caps;">l + l </span>and<span style="font-variant: small-caps;"> d + d)</span> and heterochiral <span style="font-variant: small-caps;">(l + d)</span> CuCl–amino acid complexes for both the positive–neutral and neutral–neutral forms for alanine, valine, and proline. Significant energy differences were not observed between different chiral active complexes (i.e., <span style="font-variant: small-caps;">d + d, l + l </span>vs.<span style="font-variant: small-caps;"> l + d),</span> and the distortions of active complexes between stereoselective systems and non-selective systems were not consistent, indicating that the geometry of the active complex is not the primary driver of the observed stereoselectivity of the SIPF reaction.https://www.mdpi.com/2075-1729/13/9/1796amino acidbiohomochiralitypolymerizationsalt-induced peptide formationstereoselective |
| spellingShingle | Allison C. Fox Jason D. Boettger Eve L. Berger Aaron S. Burton The Role of the CuCl Active Complex in the Stereoselectivity of the Salt-Induced Peptide Formation Reaction: Insights from Density Functional Theory Calculations Life amino acid biohomochirality polymerization salt-induced peptide formation stereoselective |
| title | The Role of the CuCl Active Complex in the Stereoselectivity of the Salt-Induced Peptide Formation Reaction: Insights from Density Functional Theory Calculations |
| title_full | The Role of the CuCl Active Complex in the Stereoselectivity of the Salt-Induced Peptide Formation Reaction: Insights from Density Functional Theory Calculations |
| title_fullStr | The Role of the CuCl Active Complex in the Stereoselectivity of the Salt-Induced Peptide Formation Reaction: Insights from Density Functional Theory Calculations |
| title_full_unstemmed | The Role of the CuCl Active Complex in the Stereoselectivity of the Salt-Induced Peptide Formation Reaction: Insights from Density Functional Theory Calculations |
| title_short | The Role of the CuCl Active Complex in the Stereoselectivity of the Salt-Induced Peptide Formation Reaction: Insights from Density Functional Theory Calculations |
| title_sort | role of the cucl active complex in the stereoselectivity of the salt induced peptide formation reaction insights from density functional theory calculations |
| topic | amino acid biohomochirality polymerization salt-induced peptide formation stereoselective |
| url | https://www.mdpi.com/2075-1729/13/9/1796 |
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