Photodynamics of alternative DNA base isoguanine

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081707%3A_____%2F19%3A00509623" target="_blank" >RIV/68081707:_____/19:00509623 - isvavai.cz</a>
Result on the web
<a href="https://pubs.rsc.org/en/content/articlepdf/2019/cp/c9cp01622h" target="_blank" >https://pubs.rsc.org/en/content/articlepdf/2019/cp/c9cp01622h</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1039/c9cp01622h" target="_blank" >10.1039/c9cp01622h</a>

Result language
angličtina
Original language name
Photodynamics of alternative DNA base isoguanine
Original language description
Isoguanine is an alternative nucleobase that has been proposed as a component of expanded genetic codes. It has also been considered as a molecule with potential relevance to primordial informational polymers. Here, we scrutinize the photodynamics of isoguanine, because photostability has been proposed as a critical criterion for the prebiotic selection of biomolecular building blocks on an early Earth. We discuss resonance-enhanced multiphoton ionization, IR-UV double resonance spectroscopy and pump-probe measurements performed for this molecule to track the excited-state behaviour of its different tautomeric forms in the gas phase. These experiments, when confronted with highly accurate quantum chemical calculations and nonadiabatic dynamics simulations provide a complete mechanistic picture of the tautomer-specific photodynamics of isoguanine. Our results indicate that UV-excited enol tautomers of isoguanine are relatively short lived and therefore photostable. In contrast, the biologically more relevant keto forms are trapped in dark n pi* states which are sufficiently long lived to participate in destructive photochemistry. The resulting lower photostability compared to canonical nucleobases may have been one of the reasons why isoguanine was not incorporated into DNA and RNA.
Czech name
—
Czech description
—

Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10403 - Physical chemistry

Project
—
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year
2019
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Similar results(10)