UV-Induced Proton-Coupled Electron Transfer in Cyclic DNA Miniduplexes
| Autor: | Yuyuan Zhang, Xi Bo Li, Bern Kohler, Anita M. Orendt, Cynthia J. Burrows, Aaron M. Fleming, Ashley A. Beckstead, Jordan Dood |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Guanine
Ultraviolet Rays Base pair Stacking 02 engineering and technology 010402 general chemistry 01 natural sciences Biochemistry Catalysis Nucleobase Electron Transport Electron transfer chemistry.chemical_compound Colloid and Surface Chemistry Tetramer Base Pairing DNA General Chemistry 021001 nanoscience & nanotechnology 0104 chemical sciences Crystallography chemistry Cyclization Excited state Nucleic Acid Conformation Protons Proton-coupled electron transfer 0210 nano-technology |
| Zdroj: | Journal of the American Chemical Society. 138:7395-7401 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/jacs.6b03216 |
| Popis: | The excited-state dynamics of two cyclic DNA miniduplexes, each containing just two base pairs, are investigated using time-resolved infrared spectroscopy. As in longer DNA duplexes, intrastrand electron transfer induced by UV excitation triggers interstrand proton transfer in the alternating miniduplex containing two out-of-phase G·C base pairs. The resulting excited state decays on a time scale of several tens of picoseconds. This state is absent when one of the two G residues is substituted by 8-oxo-7,8-dihydroguanine, a modification that is suggested to disrupt base stacking, while maintaining base pairing. These findings demonstrate that a nucleobase tetramer arranged as two stacked base pairs accurately captures the interplay between intrastrand and interstrand decay channels. The similar signals seen in the miniduplexes and longer sequences suggest that excited states in the latter rapidly localize on two adjacent base pairs. |
| Databáze: | OpenAIRE |
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