Formamide-Based Prebiotic Synthesis of Nucleobases: A Kinetically Accessible Reaction Route

Journal Article · Wed Dec 14 04:00:00 EST 2011 · Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

DOI:https://doi.org/10.1021/jp209886b· OSTI ID:1564829

Šponer, Judit E. ^[1]; Mládek, Arnošt ^[2]; Šponer, Jiří ^[1]; Fuentes-Cabrera, Miguel ^[3]

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1. Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, CZ-61265 Brno, Czech Republic; CEITEC-Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, CZ-62500 Brno, Czech Republic
2. Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, CZ-61265 Brno, Czech Republic
3. Center for Nanophase Materials Sciences and Computer Sciences and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, P.O. Box 2008, Oak Ridge, Tennessee 37831-6494, United States

Synthesis of nucleobases in nonaqueous environments is an alternative way for the emergence of terrestrial life, which could solve the fundamental problem connected to the hydrolytic instability of nucleic acid components in an aqueous environment. In this contribution, we present a plausible reaction route for the prebiotic synthesis of nucleobases in formamide, which does not require participation of the formamide trimer and aminoimidazole-carbonitrile intermediates. The computed activation energy of the proposed pathway is noticeably higher than that of the HCN-based synthetic route, but it is still feasible under the experimental conditions of the Saladino synthesis. We show that, albeit both the pyrimidine and purine ring formation utilizes the undissociated form of formamide, the dehydration product of formamide, HCN, may also play a key role in the mechanism. The rate determining step of the entire reaction path is the cyclization of the diaza-pentanimine precursor. The subsequent formation of the imidazole ring proceeds with a moderate activation energy. Our calculations thus demonstrate that the experimentally suggested reaction path without the involvement of aminoimidazole-carbonitrile intermediates is also a viable alternative for the nonaqueous synthesis of nucleobases.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Univ. of California, Oakland, CA (United States)
• Sponsoring Organization: USDOE Office of Science
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1564829
• Journal Information: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory Journal Issue: 1 Vol. 116; ISSN 1089-5639
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

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