Reaction Routes for Experimentally Observed Intermediates in the Prebiotic Formation of Nucleobases under High-Temperature Conditions
| Autor: | Brooke Ross, Chelesa Fearce, Yassin A. Jeilani, Minh Tho Nguyen, Huynh Minh Hung, Nasrin Aweis |
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| Přispěvatelé: | Pharmaceutical and Pharmacological Sciences, Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling |
| Rok vydání: | 2018 |
| Předmět: |
Formamide
chemistry.chemical_classification 010405 organic chemistry Chemistry Guanine Biomolecule Radical 010402 general chemistry Photochemistry Xanthine 01 natural sciences 0104 chemical sciences Nucleobase chemistry.chemical_compound Density functional theory Physical and Theoretical Chemistry Hypoxanthine |
| Zdroj: | The Journal of Physical Chemistry A. 122:2992-3003 |
| ISSN: | 1520-5215 1089-5639 |
| Popis: | The prebiotic synthesis of nucleobases is of particular interest, given the experimental evidence that indicated formation of the nucleobases under abiotic conditions on the Early Earth under high-temperature conditions. Biomolecules have been formed under meteoritic impact scenarios that lead to high temperature and the generation of high energy. Free radical pathways for the formation of biomolecules are appropriate under these conditions. Density functional theory computations were used to study the free radical routes for the formation of nucleobases at the UB3LYP/6-311G(d,p) level. We have found that both 5-aminoimidazole-4-carboxamide (AICA) and 5-(formylamino)imidazole-4-carboxamide (fAICA) are formed first from formamide then the nucleobases are formed. Calculated results show the radical reaction routes of AICA as a precursor for guanine. Both hypoxanthine and xanthine are formed from radical pathways of fAICA. In addition, generation of imino-AICA and imino-fAICA has been shown for the first time to be needed for the production of adenine, purine, and isoguanine. Formation of hypoxanthine and adenine/purine from fAICA and imino-fAICA, respectively, is consistent with experiments performed nearly seven decades ago. |
| Databáze: | OpenAIRE |
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