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Structural and energetic characterization of the emissive RNA alphabet based on the isothiazolo[4,3-: D] pyrimidine heterocycle core

We present theoretical characterization of fluorescent non-natural nucleobases, tzA, tzG, tzC, and tzU, derived from the isothiazolo[4,3-d]pyrimidine heterocycle. Consistent with the experimental evidence, our calculations show that the non-natural bases have minimal impact on the geometry and stability of the classical Watson-Crick base pairs, allowing them to accurately mimic natural bases in a RNA duplex, in terms of H-bonding. In contrast, our calculations indicate that H-bonded base pairs involving the Hoogsteen edge are destabilized relative to their natural counterparts. Analysis of the photophysical properties of the non-natural bases allowed us to correlate their absorption/emission peaks to the strong impact of the modification on the energy of the lowest unoccupied molecular orbital, LUMO, which is stabilized by roughly 1.0-1.2 eV relative to the natural analogues, while the highest occupied molecular orbital, HOMO, is not substantially affected. As a result, the HOMO-LUMO gap is reduced from 5.3-5.5 eV in the natural bases to 4.0-4.4 eV in the modified ones, with a consequent bathochromic shift in the absorption and emission spectra

The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST). For computer time, this research used the resources of the Supercomputing Laboratory at King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia, project K1017. A. P. thanks the Spanish MINECO for a project CTQ2014-59832-JIN

Royal Society of Chemistry (RSC)

Manager: Ministerio de Economía y Competitividad (Espanya)
Author: Chawla, Mohit
Poater Teixidor, Albert
Oliva, Romina
Cavallo, Luigi
Abstract: We present theoretical characterization of fluorescent non-natural nucleobases, tzA, tzG, tzC, and tzU, derived from the isothiazolo[4,3-d]pyrimidine heterocycle. Consistent with the experimental evidence, our calculations show that the non-natural bases have minimal impact on the geometry and stability of the classical Watson-Crick base pairs, allowing them to accurately mimic natural bases in a RNA duplex, in terms of H-bonding. In contrast, our calculations indicate that H-bonded base pairs involving the Hoogsteen edge are destabilized relative to their natural counterparts. Analysis of the photophysical properties of the non-natural bases allowed us to correlate their absorption/emission peaks to the strong impact of the modification on the energy of the lowest unoccupied molecular orbital, LUMO, which is stabilized by roughly 1.0-1.2 eV relative to the natural analogues, while the highest occupied molecular orbital, HOMO, is not substantially affected. As a result, the HOMO-LUMO gap is reduced from 5.3-5.5 eV in the natural bases to 4.0-4.4 eV in the modified ones, with a consequent bathochromic shift in the absorption and emission spectra
The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST). For computer time, this research used the resources of the Supercomputing Laboratory at King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia, project K1017. A. P. thanks the Spanish MINECO for a project CTQ2014-59832-JIN
Document access: http://hdl.handle.net/2072/298559
Language: eng
Publisher: Royal Society of Chemistry (RSC)
Rights: Tots els drets reservats
Subject: Nucleòsids
Nucleosides
Title: Structural and energetic characterization of the emissive RNA alphabet based on the isothiazolo[4,3-: D] pyrimidine heterocycle core
Type: info:eu-repo/semantics/article
Repository: Recercat

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