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Chen Z, Wang X, Jia M, He X, Pan H, Chen J. Ribose and Deoxyribose Group Alter Excited-State Dynamics of 5-Azacytosine in Solution. Photochem Photobiol 2024; 100:291-297. [PMID: 35993879 DOI: 10.1111/php.13696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 08/16/2022] [Indexed: 10/15/2022]
Abstract
5-Azacytosine (5-AC) is one of the best interesting noncanonical nucleobases due to its functionalization and structural imitation of natural bases. 5-AC can be used as the scaffold of two important chemotherapeutic medicines, 5-azacytidine and 2'-deoxy-5-azacytidine. Furthermore, increased sensitivity to UV leads to the photochemical effects of 5-AC also attracted attention. Yet, no study has been reported to explore the effect of glycosyl groups on the photophysical and photochemical properties of 5-AC, which can help to reveal the photostability of related actual clinic drugs. In this study, the excited-state dynamics of 5-azacytidine and 2'-deoxy-5-azacytidine are studied by femtosecond transient absorption and quantum-chemical calculations while revisiting that of 5-AC with a wider probe spectral range. It is shown that glycosyl substitution on the N1 position leads to ultrafast excited-state relaxation within several picoseconds in both nucleosides, which is distinct compared with the 17 ps lifetime seen in 5-AC. It is proposed that these changes are due to altering the energy level of the dark nπ* state. Moreover, our results suggest that it should be cautioned to simply replace sugar groups with methyl groups when doing a theoretical calculation study on nucleobases and their derivatives.
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Affiliation(s)
- Ziwei Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Xueli Wang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Menghui Jia
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Xiaoxiao He
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Haifeng Pan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, China
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2
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Liu M, O'Reilly D, Schwob L, Wang X, Zamudio-Bayer V, Lau JT, Bari S, Schlathölter T, Poully JC. Direct Observation of Charge, Energy, and Hydrogen Transfer between the Backbone and Nucleobases in Isolated DNA Oligonucleotides. Chemistry 2023; 29:e202203481. [PMID: 36478608 DOI: 10.1002/chem.202203481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022]
Abstract
Understanding how charge and energy, as well as protons and hydrogen atoms, are transferred in molecular systems as a result of an electronic excitation is fundamental for understanding the interaction between ionizing radiation and biological matter on the molecular level. To localize the excitation at the atomic scale, it was chosen to target phosphorus atoms in the backbone of gas-phase oligonucleotide anions and cations, by means of resonant photoabsorption at the L- and K-edges. The ionic photoproducts of the excitation process were studied by a combination of mass spectrometry and X-ray spectroscopy. The combination of absorption site selectivity and photoproduct sensitivity allowed the identification of X-ray spectral signatures of specific processes. Moreover, charge and/or energy as well as H transfer from the backbone to nucleobases has been directly observed. Although the probability of one versus two H transfer following valence ionization depends on the nucleobase, ionization of sugar or phosphate groups at the carbon K-edge or the phosphorus L-edge mainly leads to single H transfer to protonated adenine. Moreover, our results indicate a surprising proton-transfer process to specifically form protonated guanine after excitation or ionization of P 2p electrons.
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Affiliation(s)
- Min Liu
- CIMAP UMR 6252, CEA/, CNRS/, ENSICAEN/, Université de Caen Normandie, Bd Becquerel, 14070, Caen, France
| | - David O'Reilly
- CIMAP UMR 6252, CEA/, CNRS/, ENSICAEN/, Université de Caen Normandie, Bd Becquerel, 14070, Caen, France
| | | | - Xin Wang
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | | | - J Tobias Lau
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.,Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Sadia Bari
- Deutsches Elektronen-Synchrotron DESY, Germany
| | - Thomas Schlathölter
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands.,University College Groningen, University of Groningen, Groningen, The Netherlands
| | - Jean-Christophe Poully
- CIMAP UMR 6252, CEA/, CNRS/, ENSICAEN/, Université de Caen Normandie, Bd Becquerel, 14070, Caen, France
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3
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The competitive mechanism between photoisomerization and excited state intramolecular proton transfer process of 2′-Hydroxychalcone system. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2022.114255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Roy Chowdhury P, Khodia S, Maity S. Solvent assisted excited-state deactivation pathways in isolated 2,7-diazaindole-S 1-3 (S = Water and Ammonia) complexes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 278:121285. [PMID: 35533603 DOI: 10.1016/j.saa.2022.121285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/13/2022] [Accepted: 04/16/2022] [Indexed: 06/14/2023]
Abstract
The role of solvent molecules in the deactivation of photo-excited 2,7-diazaindole (DAI) - (H2O)1-3 and DAI - (NH3)1-3 complexes were computationally investigated. An excited-state proton transfer (ESPT) path from the solvent to the DAI molecule was followed using the TD-DFT-D4 (B3LYP) level of theory. The computed potential energy profile of ESPT process has shown intersection between ππ* and nπ* states facilitated via relative stabilization of the nπ* state with decreasing N(7)-Hb bond length. The ESPT process, starting from the DAI-Sn (ππ*) state, crosses through a barrier ranging from 27 to 36 kJmol-1 for water complexes and 26-30 kJmol-1 for ammonia complexes. The energy of the excited state was rapidly decreased with a shorter N(7)-Hb bond length. Subsequently, a significant trend of finding a second intersection between the ground and the excited state was observed for all the complexes. The results firmly suggested a significant deactivation channel of excited azaindole derivatives. In the present system, two competing channels, ESPT and ESHT, were found to be energetically accessible. The energy barriers associated with the ESPT barriers for DAI-(H2O)1-3 complexes are similar to the ESHT barrier, depicting equal dominance of both processes. The increased basicity of the N(7) atom in the excited state resulted a facile ESPT process from the water to N(7) of the DAI molecule. However, DAI-(NH3)1-3 complexes show clear preference for ESHT over ESPT process owing to its higher gas-phase pKa value making it a poor proton donor. The above systems can be used as a model to computationally and experimentally investigate the competing radiative and deactivation pathways of photo-excited solvated complexes of N-H-bearing bio-relevant molecules via proton and hydrogen transfer reactions.
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Affiliation(s)
| | - Saurabh Khodia
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana 502285, India
| | - Surajit Maity
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana 502285, India.
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Mansour R, Toldo JM, Barbatti M. Role of the Hydrogen Bond on the Internal Conversion of Photoexcited Adenosine. J Phys Chem Lett 2022; 13:6194-6199. [PMID: 35767744 DOI: 10.1021/acs.jpclett.2c01554] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Experiments and theory have revealed that hydrogen bonds modify the excited-state lifetimes of nucleosides compared to nucleobases. Nevertheless, how these bonds impact the internal conversion is still unsettled. This work simulates the non-adiabatic dynamics of adenosine conformers in the gas phase with and without hydrogen bonds between the sugar and adenine moieties. The isomer containing the hydrogen bond (syn) exhibits a significantly shorter excited-state lifetime than the isomer without it (anti). However, internal conversion through electron-driven proton transfer between sugar and adenine plays only a minor (although non-negligible) role in the photophysics of adenosine. Either with or without hydrogen bonds, photodeactivation preferentially occurs following the ring-puckering pathways. The role of the hydrogen bond is to avoid the sugar rotation relative to adenine, shortening the distance to the ring-puckering internal conversion.
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Affiliation(s)
- Ritam Mansour
- Aix Marseille University, CNRS, ICR, Marseille 13397, France
| | - Josene M Toldo
- Aix Marseille University, CNRS, ICR, Marseille 13397, France
| | - Mario Barbatti
- Aix Marseille University, CNRS, ICR, Marseille 13397, France
- Institut Universitaire de France, 75231 Paris, France
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Khodia S, Maity S. A combined experimental and computational study on the deactivation of a photo-excited 2,2'-pyridylbenzimidazole-water complex via excited-state proton transfer. Phys Chem Chem Phys 2022; 24:12043-12051. [PMID: 35537136 DOI: 10.1039/d2cp01121b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this report, we present solvent assisted excited-state proton transfer coupled to the deactivation of a photo-excited 2,2'-pyridylbenzimidazole bound to a single water molecule. Experimentally, the mass-selected 1 : 1 complex was probed using two-colour resonant two-photon ionization (2C-R2PI) and UV-UV hole-burning (HB) spectroscopy in a supersonically jet-cooled molecular beam. Computationally, three structural isomers were identified as the normal, the tautomer and the proton transfer product of the PBI-H2O complex in the excited S1 state using B3LYP-D4/def2-TZVPP and ADC(2) (MP2)/cc-pVDZ levels of theory. The most stable form in the ground state, i.e., the normal form, was identified using the excitation spectrum in the 30 544 to 30 936 cm-1 region. The 2C-R2PI spectrum showed a sudden break-off above the 000 + 392 cm-1 region, even though the Frack-Condon activity of the S1 ← S0 transition was measured beyond 000 + 1000 cm-1 in the HB spectrum. The intensity of the bands associated with the excited state intermolecular vibrational modes near the break-off region was found to be drastically decreased, which indicates efficient quantum mechanical tunnelling along the hydrogen transfer coordinate. The sudden disappearance of the intermolecular vibrational modes in the spectrum revealed the existence of a deactivation channel in the PBI-H2O complex near 392-450 cm-1 above the 000 transition. The computational investigation predicted that the deactivation of the excited-state occurred via the intersection between the S1 and S0 states, which was associated with the proton transfer from the H2O to the PBI molecule along the O(3)-H(4)→N(5) coordinate. The highest energy structure was identified as the point of intersection between the nπ* (S2) and ππ* (S1) states. The associated barrier height was experimentally determined to be 392-450 cm-1, which showed a reasonable agreement with the calculated excited-state proton transfer barrier. Competing reaction channels such as dissociation and tautomerization were found to be highly energetically inaccessible.
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Affiliation(s)
- Saurabh Khodia
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana, India.
| | - Surajit Maity
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana, India.
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Janicki MJ, Szabla R, Šponer J, Góra RW. Photoinduced water-chromophore electron transfer causes formation of guanosine photodamage. Phys Chem Chem Phys 2022; 24:8217-8224. [PMID: 35319053 DOI: 10.1039/d2cp00801g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UV-induced photolysis of aqueous guanine nucleosides produces 8-oxo-guanine and Fapy-guanine, which can induce various types of cellular malfunction. The mechanistic rationale underlying photodestructive processes of guanine nucleosides is still largely obscure. Here, we employ accurate quantum chemical calculations and demonstrate that an excited-state non-bonding interaction of guanosine and a water molecule facilitates the electron-driven proton transfer process from water to the chromophore fragment. This subsequently allows for the formation of a crucial intermediate, namely guanosine photohydrate. Further (photo)chemical reactions of this intermediate lead to the known products of guanine photodamage.
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Affiliation(s)
- Mikołaj J Janicki
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
| | - Rafał Szabla
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Robert W Góra
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
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