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Zubova E, Pokluda A, Dvořáková H, Krupička M, Cibulka R. Exploring the Reactivity of Flavins with Nucleophiles Using a Theoretical and Experimental Approach. Chempluschem 2023:e202300547. [PMID: 38064649 DOI: 10.1002/cplu.202300547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/30/2023] [Indexed: 01/13/2024]
Abstract
Covalent adducts of flavin cofactors with nucleophiles play an important role in non-canonical function of flavoenzymes as well as in flavin-based catalysis. Herein, the interaction of flavin derivatives including substituted flavins (isoalloxazines), 1,10-ethylene-bridged flavinium salts, and non-substituted alloxazine and deazaflavin with selected nucleophiles was investigated using an experimental and computational approach. Triphenylphosphine or trimethylphosphine, 1-nitroethan-1-ide, and methoxide were selected as representatives of neutral soft, anionic soft, and hard nucleophiles, respectively. The interactions were investigated using UV/Vis and 1 H NMR spectroscopy as well as by DFT calculations. The position of nucleophilic attack estimated using the calculated Gibbs free energy values was found to correspond with the experimental data, favouring the addition of phosphine and 1-nitroethan-1-ide into position N(5) and methoxide into position C(10a) of 1,10-ethylene-bridged flavinium salts. The calculated Gibbs free energy values were found to correlate with the experimental redox potentials of the flavin derivatives tested. These findings can be utilized as valuable tools for the design of artificial flavin-based catalytic systems or investigating the mechanism of flavoenzymes.
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Affiliation(s)
- Ekaterina Zubova
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
| | - Adam Pokluda
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
| | - Hana Dvořáková
- Central Laboratories, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
| | - Martin Krupička
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
| | - Radek Cibulka
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
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Golczak A, Prukała D, Sikorska E, Gierszewski M, Cherkas V, Kwiatek D, Kubiak A, Varma N, Pędziński T, Murphree S, Cibulka R, Mrówczyńska L, Kolanowski JL, Sikorski M. Tetramethylalloxazines as efficient singlet oxygen photosensitizers and potential redox-sensitive agents. Sci Rep 2023; 13:13426. [PMID: 37591918 PMCID: PMC10435492 DOI: 10.1038/s41598-023-40536-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 08/12/2023] [Indexed: 08/19/2023] Open
Abstract
Tetramethylalloxazines (TMeAll) have been found to have a high quantum yield of singlet oxygen generation when used as photosensitizers. Their electronic structure and transition energies (S0 → Si, S0 → Ti, T1 → Ti) were calculated using DFT and TD-DFT methods and compared to experimental absorption spectra. Generally, TMeAll display an energy diagram similar to other derivatives belonging to the alloxazine class of compounds, namely π,π* transitions are accompanied by closely located n,π* transitions. Photophysical data such as quantum yields of fluorescence, fluorescence lifetimes, and nonradiative rate constants were also studied in methanol (MeOH), acetonitrile (ACN), and 1,2-dichloroethane (DCE). The transient absorption spectra were also analyzed. To assess cytotoxicity of new compounds, a hemolytic assay was performed using human red blood cells (RBC) in vitro. Subsequently, fluorescence lifetime imaging experiments (FLIM) were performed on RBC under physiological and oxidative stress conditions alone or in the presence of TMeAll allowing for pinpointing changes caused by those compounds on the intracellular environment of these cells.
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Affiliation(s)
- Anna Golczak
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznan, Poland
| | - Dorota Prukała
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznan, Poland
| | - Ewa Sikorska
- Poznań University of Economics and Business, Al. Niepodległości 10, 61-875, Poznan, Poland
| | - Mateusz Gierszewski
- Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland
| | - Volodymyr Cherkas
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Dorota Kwiatek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Adam Kubiak
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznan, Poland
| | - Naisargi Varma
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznan, Poland
| | - Tomasz Pędziński
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznan, Poland
| | - Shaun Murphree
- Department of Chemistry, Allegheny College, 520 N. Main Street, Meadville, PA, USA
| | - Radek Cibulka
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technicka 5, 16628, Prague 6, Czech Republic.
| | - Lucyna Mrówczyńska
- Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614, Poznan, Poland.
| | - Jacek Lukasz Kolanowski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland.
| | - Marek Sikorski
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznan, Poland.
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