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Sato R, Yamada Y, Kashihara W, Nishihara T, Tanabe K, Xu YZ, Suzuki T. Excited state properties of 5-fluoro-4-thiouridine derivative †. Photochem Photobiol 2024; 100:434-442. [PMID: 38312100 DOI: 10.1111/php.13918] [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: 09/26/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/06/2024]
Abstract
The excited state properties of thionated 5-fluorouridine (2',3',5'-tri-O-acetyl-5-fluoro-4-thiouridine; ta5F4TUrd), synthesized with Lawesson's reagent, have been intensively investigated with nanosecond transient absorption spectroscopy, time-resolved thermal lensing, near-infrared emission, and quantum chemical calculation. The intrinsic triplet lifetime of ta5F4TUrd was determined to be4.2 ± 0.7 μs in acetonitrile, and the formation quantum yield of the excited triplet state was as large as0.79 ± 0.01 . The quenching rate constants of the triplet ta5F4TUrd by the dissolved oxygen molecule and by the self-quenching process were found to be nearly equal to the diffusion-controlled rate of acetonitrile. The quantum yield of the singlet molecular oxygen produced through energy transfer between the triplet ta5F4TUrd and the dissolved oxygen,Φ Δ , was successfully determined to be0.61 ± 0.02 under the oxygen-saturated condition. From the oxygen concentration dependence of theΦ Δ value, the fraction of triplet ta5F4TUrd quenched by dissolved oxygen which gives rise to the 1 O2 * formation,S Δ , was successfully obtained to be0.78 ± 0.01 , which was the largest among the thionucleobases and the thionucleosides reported so far. This could be due to the lower energy and/or the ππ* character of the triplet state.
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Affiliation(s)
- Rin Sato
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Yoshino Yamada
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Wataru Kashihara
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Tatsuya Nishihara
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Kazuhito Tanabe
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
| | - Yao-Zhong Xu
- School of Life, Health and Chemical Sciences, The Open University, Keynes, UK
| | - Tadashi Suzuki
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Sagamihara, Kanagawa, Japan
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Xie BB, Tang XF, Liu XY, Chang XP, Cui G. Mechanistic photophysics and photochemistry of unnatural bases and sunscreen molecules: insights from electronic structure calculations. Phys Chem Chem Phys 2021; 23:27124-27149. [PMID: 34849517 DOI: 10.1039/d1cp03994f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photophysics and photochemistry are basic subjects in the study of light-matter interactions and are ubiquitous in diverse fields such as biology, energy, materials, and environment. A full understanding of mechanistic photophysics and photochemistry underpins many recent advances and applications. This contribution first provides a short discussion on the theoretical calculation methods we have used in relevant studies, then we introduce our latest progress on the mechanistic photophysics and photochemistry of two classes of molecular systems, namely unnatural bases and sunscreens. For unnatural bases, we disclose the intrinsic driving forces for the ultrafast population to reactive triplet states, impacts of the position and degree of chalcogen substitutions, and the effects of complex environments. For sunscreen molecules, we reveal the photoprotection mechanisms that dissipate excess photon energy to the surroundings by ultrafast internal conversion to the ground state. Finally, relevant theoretical challenges and outlooks are discussed.
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Affiliation(s)
- Bin-Bin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Xiu-Fang Tang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu, Sichuan, 610068, China
| | - Xue-Ping Chang
- College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, P. R. China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China.
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Nowak-Karnowska J, Zielińska K, Milecki J, Skalski B. Thermally reversible and irreversible interstrand photocrosslinking of 5-chloro-2'-deoxy-4-thiouridine modified DNA oligonucleotides. Org Biomol Chem 2021; 19:1292-1295. [PMID: 33508059 DOI: 10.1039/d0ob02422h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe highly efficient interstrand photocrosslinking of a DNA duplex containing 5-chloro-2'-deoxy-4-thiouridine (ClSdU) in one strand, proceeding via a two-step photochemical cascade, involving the formation of a thermally reversible crosslink between ClSdU and thymidine in the target strand and its subsequent conversion to a thermally stable fluorescent crosslink. These results show that ClSdU has great potential to be a valuable DNA photo-crosslinking reagent for chemical biology applications.
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Affiliation(s)
- Joanna Nowak-Karnowska
- Department of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.
| | - Karolina Zielińska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Jan Milecki
- Department of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.
| | - Bohdan Skalski
- Department of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland. and Center for Advanced Technology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 10, 61-614 Poznań, Poland
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Peng Q, Zhu YH, Zhang TS, Liu XY, Fang WH, Cui G. Selenium substitution effects on excited-state properties and photophysics of uracil: a MS-CASPT2 study. Phys Chem Chem Phys 2020; 22:12120-12128. [PMID: 32440669 DOI: 10.1039/d0cp01369b] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The photophysics of selenium-substituted nucleobases has attracted recent experimental attention because they could serve as potential photosensitizers in photodynamic therapy. Herein, we present a comprehensive MS-CASPT2 study on the spectroscopic and excited-state properties, and photophysics of 2-selenouracil (2SeU), 4-selenouracil (4SeU), and 2,4-selenouracil (24SeU). Relevant minima, conical intersections, crossing points, and excited-state relaxation paths in the lowest five electronic states (i.e., S0, S1, S2, T2, and T1) are explored. On the basis of these results, their photophysical mechanisms are proposed. Upon photoirradiation to the bright S2 state, 2SeU quickly relaxes to its S2 minimum and then moves in an essentially barrierless way to a nearby S2/S1 conical intersection near which the S1 state is populated. Next, the S1 system arrives at an S1/T2/T1 intersection where a large S1/T1 spin-orbit coupling of 430.8 cm-1 makes the T1 state populated. In this state, a barrier of 6.8 kcal mol-1 will trap 2SeU for a while. In parallel, for 4SeU or 24SeU, the system first relaxes to the S2 minimum and then overcomes a small barrier to approach an S2/S1 conical intersection. Once hopping to the S1 state, there exists an extended region with very close S1, T2, and T1 energies. Similarly, a large S1/T1 spin-orbit coupling of 426.8 cm-1 drives the S1→ T1 intersystem crossing process thereby making the T1 state populated. Similarly, an energy barrier heavily suppresses electronic transition to the S0 state. The present work manifests that different selenium substitutions on uracil can lead to a certain extent of different vertical and adiabatic excitation energies, excited-state properties, and relaxation pathways. These insights could help understand the photophysics of selenium-substituted nucleobases.
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Affiliation(s)
- Qin Peng
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
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Xie BB, Cui CX. Theoretical studies on photo-induced cycloaddition and (6-4) reactions of the thymidine:4-thiothymidine dimer in a DNA duplex. Phys Chem Chem Phys 2019; 21:2006-2016. [DOI: 10.1039/c8cp07063f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Photo-induced cycloaddition and (6-4) reactions of the thymidine:4-thiothymidine dimer in a DNA duplex.
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Affiliation(s)
- Bin-Bin Xie
- Hangzhou Institute of Advanced Studies
- Zhejiang Normal University
- Hangzhou 311231
- P. R. China
- Key Laboratory of Theoretical and Computational Photochemistry
| | - Cheng-Xing Cui
- School of Chemistry and Chemical Engineering
- Henan Institute of Science and Technology
- Xinxiang 453003
- P. R. China
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Chang XP, Xiao P, Han J, Fang WH, Cui G. A theoretical study of the light-induced cross-linking reaction of 5-fluoro-4-thiouridine with thymine. Phys Chem Chem Phys 2017; 19:13524-13533. [PMID: 28498381 DOI: 10.1039/c7cp01511a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In contrast to photophysics of thio-substituted nucleobases, their photoinduced cross-linking reactions with canonical nucleobases remain scarcely investigated computationally. In this work, we have adopted combined CASPT2/PCM//CASSCF and B3LYP-D3/PCM electronic structure methods to study this kind of photochemical reaction of 5-fluoro-4-thiouridine (truncated 5-fluoro-1-methyl-4-thiouracil used in calculations) and 1-methylthymine (referred to as thymine for clarity hereinafter). On the basis of CASPT2/PCM computed results, we have proposed two efficient excited-state relaxation pathways to populate the lowest T1 state of the complex of 5-fluoro-1-methyl-4-thiouracil and thymine from its initially populated S2(1ππ*) state. In the first one, the S2 system first hops to the S1 state via an S2/S1 conical intersection, followed by a direct S1 → T1 intersystem crossing process enhanced by large S1/T1 spin-orbit coupling. In the second path, the resultant S1 system first jumps to the T2 state, from which an efficient T2 → T1 internal conversion occurs. The T1 cross-linking reaction is overall divided into two phases. The first phase is a stepwise and nonadiabatic photocyclization reaction, which starts from the T1 complex and ends up with an S0 thietane intermediate. The second phase is a thermal reaction. The system first rearranges its four- and six-membered rings to form three new rings; then, an S0 fluorine atom transfer occurs, followed by the formation of photoproducts. Finally, the present work paves the way for studying light-induced cross-linking reactions of thionucleobases with canonical bases in DNA and RNA.
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Affiliation(s)
- Xue-Ping Chang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
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Nowak-Karnowska J, Chebib Z, Milecki J, Franzen S, Skalski B. Highly efficient fluorescent interstrand photo-crosslinking of DNA duplexes labeled with 5-fluoro-4-thio-2'-o-methyluridine. Chembiochem 2014; 15:2045-9. [PMID: 25111776 DOI: 10.1002/cbic.201402182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Indexed: 02/03/2023]
Abstract
The formation of a fluorescent photoadduct between 5-fluoro-4-thiouridine ((FS) U), in the sequence context 5'-A(FS) UA-3' and incorporated into a synthetic oligonucleotide either at its 3'- or 5'-end, and one of the thymines of the TAT motif in a complementary target DNA strand led to photo-crosslinking of the two strands for several oligonucleotide constructs. Enzymatic digestion, MS, UV, and fluorescence spectral analyses of the interstrand crosslinked oligonucleotides revealed the identity of the thymidine that participates in the photo-crosslinking reaction as well as the diastereomeric structures of the crosslinks. The proposed pathways of interstrand photo-crosslinking are supported by experiments with isotopically labeled oligonucleotide constructs and visualized by means of molecular dynamics simulations.
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Affiliation(s)
- Joanna Nowak-Karnowska
- Centre of Advanced Technology, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań (Poland)
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5-Fluoro-4-thiouridine phosphoramidite: new synthon for introducing photoaffinity label into oligodeoxynucleotides. Bioorg Med Chem 2011; 19:6098-106. [PMID: 21917468 DOI: 10.1016/j.bmc.2011.08.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 08/09/2011] [Accepted: 08/14/2011] [Indexed: 11/21/2022]
Abstract
The synthesis of phosphoramidite of 5-fluoro-4-thio-2'-O-methyluridine is described. An appropriate set of protecting groups was optimized including the 4-thio function introduced via 4-triazolyl as the 4-(2-cyanoethyl)thio derivative, and the t-butyldimethyl silyl for 2' and 3' hydroxyl protection, enabling efficient synthesis of the phosphoramidite. These protecting groups prevented unwanted side reactions during oligonucleotide synthesis. The utility of the proposed synthetic route was proven by the preparation of several oligonucleotides via automated synthesis. Photochemical experiments confirmed the utility of the synthon.
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Shetlar MD, Chung J. The (5‐4) and (6‐4) Adducts of 1‐Methylthymine and Their Dewar Valence Isomers. Photochem Photobiol 2011; 87:802-17. [DOI: 10.1111/j.1751-1097.2011.00932.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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