Document Type
Article
Publication Date
2-22-2022
Abstract
Oxo and amino substituted purines and pyrimidines have been suggested as protonucleobases participating in ancient pre-RNA forms. Considering electromagnetic radiation as a key environmental selection pressure on early Earth, the investigation of the photophysics of modified nucleobases is crucial to determine their viability as nucleobases’ ancestors and to understand the factors that rule the photostability of natural nucleobases. In this Letter, we combine femtosecond transient absorption spectroscopy and quantum mechanical simulations to reveal the photochemistry of 4-pyrimidinone, a close relative of uracil. Irradiation of 4-pyrimidinone with ultraviolet radiation populates the S1(ππ*) state, which decays to the vibrationally excited ground state in a few hundred femtoseconds. Analysis of the postirradiated sample in water reveals the formation of a 6-hydroxy-5H-photohydrate and 3-(N-(iminomethyl)imino)propanoic acid as the primary photoproducts. 3-(N-(Iminomethyl)imino)propanoic acid originates from the hydrolysis of an unstable ketene species generated from the C4-N3 photofragmentation of the pyrimidine core.
Keywords
absorption, absorption spectroscopy, nucleobases, potential energy, pyrimidine
Language
English
Publication Title
Journal of Physical Chemistry Letters
Grant
1800052
Rights
© 2022 The Authors. Published by American Chemical Society. This is an Open Access work distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Vos, E., Hoehn, S. J., Krul, S. E., Crespo-Hernández, C. E., González-Vázquez, J., & Corral, I. (2022). Disclosing the role of C4-oxo substitution in the photochemistry of DNA and RNA pyrimidine monomers: formation of photoproducts from the vibrationally excited ground state. J. Phys. Chem. Lett. 2022, 13, 8, 2000–2006
Manuscript Version
Final Publisher Version