1
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Abou-Hatab S, Matsika S. Excited state hydrogen or proton transfer pathways in microsolvated n-cyanoindole fluorescent probes. Phys Chem Chem Phys 2024; 26:4511-4523. [PMID: 38240574 DOI: 10.1039/d3cp04844f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The sensitivity of the fluorescence properties of n-cyanoindole (n-CNI) fluorescent probes to the microenvironment makes them potential reporters of protein conformation and hydration. The fluorescence intensity of 5-CNI, 6-CNI, and 7-CNI is quenched when exposed to water solvent whereas substitution on position 4 of indoles dramatically increases it. A potential mechanism for this sensitivity to water may be similar to that found in indole. The fluorescence of indole is found to be quenched when interacting with water and ammonia solvent molecules via radiationless decay through an S1 (πσ*)/S0 conical intersection caused by excited state proton or hydrogen transfer to the solvent molecules. In this study we examine this fluorescence quenching mechanism along the N-H bond stretch of n-CNI probes using water cluster models and quantum mechanical calculations of the excited states. We find that n-CNI-(H2O)1-2 clusters form cyclic or non-cyclic structures via hydrogen bonds which lead to different photochemical reaction paths that can potentially quench the fluorescence by undergoing internal conversion from S1 to S0. However, the existence of a high energy barrier along the potential energy surface of the S1 state in most cases prevents this from occurring. We show that substitution on position 4 leads to the highest energy barrier that prevents the fluorophore from accessing these non-radiative channels, in agreement with its high intensity. We also find that the energy barrier in the S1 state of non-cyclic 5-CNI-(H2O)1-2 excited complexes decreases as the number of water molecules increases, which suggests great sensitivity of the fluorescence quenching on the aqueous environment.
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2
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Russel NS, Kodali G, Stanley RJ, Narayanan M. Screening for Novel Fluorescent Nucleobase Analogues Using Computational and Experimental Methods: 2-Amino-6-chloro-8-vinylpurine (2A6Cl8VP) as a Case Study. J Phys Chem B 2023; 127:7858-7871. [PMID: 37698525 DOI: 10.1021/acs.jpcb.3c03618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
Novel fluorescent nucleic acid base analogues (FBAs) with improved optical properties are needed in a variety of biological applications. 2-Amino-6-chloro-8-vinylpurine (2A6Cl8VP) is structural analogue of two existing highly fluorescent FBAs, 2-aminopurine (2AP) and 8-vinyladenine (8VA), and can therefore be expected to have similar base pairing as well as better optical properties compared to its counterparts. In order to determine the absorption and fluorescence properties of 2A6Cl8VP, as a first step, we used TD-DFT calculations and the polarizable continuum model for simulating the solvents and computationally predicted absorption and fluorescence maxima. To test the computational predictions, we also synthesized 2A6Cl8VP and measured its UV/vis absorbance, fluorescence emission, and fluorescence lifetime. The computationally predicted absorbance and fluorescence maxima of 2A6Cl8VP are in reasonable agreement to the experimental values and are significantly redshifted compared to 2AP and 8VA, allowing for its specific excitation. The fluorescence quantum yield of 2A6Cl8VP, however, is significantly lower than those of 2AP and 8VA. Overall, 2A6Cl8VP is a novel fluorescent nucleobase analogue, which can be useful in studying structural, biophysical, and biochemical applications.
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Affiliation(s)
- Nadim Shahriar Russel
- Department of Chemistry, Temple University, 1901 N. Broad Street, Philadelphia, Pennsylvania 19122, United States
| | - Goutham Kodali
- GlowDNA LLC., Malvern, Pennsylvania 19355, United States
| | - Robert J Stanley
- Department of Chemistry, Temple University, 1901 N. Broad Street, Philadelphia, Pennsylvania 19122, United States
| | - Madhavan Narayanan
- Department of Physical Sciences, Benedictine University, 5700 College Rd, Lisle, Illinois 60532, United States
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3
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Jezuita A, Wieczorkiewicz PA, Krygowski TM, Szatylowicz H. Influence of the Solvent on the Stability of Aminopurine Tautomers and Properties of the Amino Group. Molecules 2023; 28:molecules28072993. [PMID: 37049758 PMCID: PMC10095612 DOI: 10.3390/molecules28072993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/23/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
Amino derivatives of purine (2-, 6-, 8-, and N-NH2) have found many applications in biochemistry. This paper presents the results of a systematic computational study of the substituent and solvent effects in these systems. The issues considered are the electron-donating properties of NH2, its geometry, π-electron delocalization in purine rings and tautomeric stability. Calculations were performed in ten environments, with 1 < ε < 109, using the polarizable continuum model of solvation. Electron-donating properties were quantitatively described by cSAR (charge of the substituent active region) parameter and π-electron delocalization by using the HOMA (harmonic oscillator model of aromaticity) index. In aminopurines, NH2 proximity interactions depend on its position and the tautomer. The results show that they are the main factor determining how solvation affects the electron-donating strength and geometry of NH2. Proximity with the NH∙∙∙HN repulsive interaction between the NH2 and endocyclic NH group results in stronger solvent effects than the proximity with two attractive NH∙∙∙N interactions. The effect of amino and nitro (previously studied) substitution on aromaticity was compared; these two groups have, in most cases, the opposite effect, with the largest being in N1H and N3H purine tautomers. The amino group has a smaller effect on the tautomeric preferences of purine than the nitro group. Only in 8-aminopurine do tautomeric preferences change: N7H is more stable than N9H in H2O.
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Affiliation(s)
- Anna Jezuita
- Faculty of Science and Technology, Jan Dlugosz University in Czestochowa, Al. Armii Krajowej 13/15, 42-200 Czestochowa, Poland
| | - Paweł A. Wieczorkiewicz
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
- Correspondence: (P.A.W.); (H.S.)
| | | | - Halina Szatylowicz
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
- Correspondence: (P.A.W.); (H.S.)
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4
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Dziuba D, Didier P, Ciaco S, Barth A, Seidel CAM, Mély Y. Fundamental photophysics of isomorphic and expanded fluorescent nucleoside analogues. Chem Soc Rev 2021; 50:7062-7107. [PMID: 33956014 DOI: 10.1039/d1cs00194a] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Fluorescent nucleoside analogues (FNAs) are structurally diverse mimics of the natural essentially non-fluorescent nucleosides which have found numerous applications in probing the structure and dynamics of nucleic acids as well as their interactions with various biomolecules. In order to minimize disturbance in the labelled nucleic acid sequences, the FNA chromophoric groups should resemble the natural nucleobases in size and hydrogen-bonding patterns. Isomorphic and expanded FNAs are the two groups that best meet the criteria of non-perturbing fluorescent labels for DNA and RNA. Significant progress has been made over the past decades in understanding the fundamental photophysics that governs the spectroscopic and environmentally sensitive properties of these FNAs. Herein, we review recent advances in the spectroscopic and computational studies of selected isomorphic and expanded FNAs. We also show how this information can be used as a rational basis to design new FNAs, select appropriate sequences for optimal spectroscopic response and interpret fluorescence data in FNA applications.
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Affiliation(s)
- Dmytro Dziuba
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France.
| | - Pascal Didier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France.
| | - Stefano Ciaco
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France. and Department of Biotechnology, Chemistry and Pharmacy, University of Siena, via Aldo Moro 2, 53100 Siena, Italy
| | - Anders Barth
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Claus A M Seidel
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France.
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5
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Sanches de Araújo AV, Valverde D, Canuto S, Borin AC. Solvation Structures and Deactivation Pathways of Luminescent Isothiazole-Derived Nucleobases: tzA, tzG, and tzI. J Phys Chem A 2020; 124:6834-6844. [PMID: 32786984 DOI: 10.1021/acs.jpca.0c03398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The photophysical relaxation pathways of tzA, tzG, and tzI luminescent nucleobases were investigated with the MS-CASPT2 quantum-chemical method and double-ζ basis sets (cc-pVDZ) in gas and condensed phases (1,4-dioxane and water) with the sequential Monte Carlo/CASPT2 and free energy gradient (FEG) methods. Solvation shell structures, in the ground and excited states, were examined with the pairwise radial distribution function (G(r)) and solute-solvent hydrogen-bond networks. Site-specific hydrogen bonding analysis evidenced relevant changes between both electronic states. The three luminescent nucleobases share a common photophysical pattern, summarized as the lowest-lying 1(ππ*) bright state that is populated directly after the absorption of radiation and evolves barrierless to the minimum energy structure, from where the excess of energy is released by fluorescence. From the 1(ππ*)min region, the conical intersection with the ground state ((ππ*/GS)CI) is not accessible due to the presence of high energetic barriers. By combining the present results with those reported earlier by us for the pyrimidine fluorescent nucleobases, we present a comprehensive description of the photophysical properties of this important class of new fluorescent nucleosides.
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Affiliation(s)
| | - Danillo Valverde
- Institute of Physics, University of São Paulo, Rua do Matão 1371, 05508-090 São Paulo, SP, Brazil
| | - Sylvio Canuto
- Institute of Physics, University of São Paulo, Rua do Matão 1371, 05508-090 São Paulo, SP, Brazil
| | - Antonio Carlos Borin
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000 São Paulo, SP, Brazil
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6
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Valverde D, Sanches de Araujo AV, Canuto S, Borin AC. Photophysics of Emissive
tz
C[Isothiazolo‐Cytidine] and
tz
U[Isothiazolo‐Uridine] Pyrimidine Analogues. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Danillo Valverde
- Institute of PhysicsUniversity of São Paulo Rua do Matão 1371 São Paulo, SP 05508-090 Brazil
| | | | - Sylvio Canuto
- Institute of PhysicsUniversity of São Paulo Rua do Matão 1371 São Paulo, SP 05508-090 Brazil
| | - Antonio Carlos Borin
- Department of Fundamental ChemistryInstitute of ChemistryUniversity of São Paulo Avenida Professor Lineu Prestes, 748 São Paulo SP, 05508-000 Brazil
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7
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Sanches de Araújo AV, Borin AC. Photochemical Relaxation Pathways of 9 H-8-Azaguanine and 8 H-8-Azaguanine. J Phys Chem A 2019; 123:3109-3120. [PMID: 30901221 DOI: 10.1021/acs.jpca.9b01397] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The photochemical reaction path approach, the MS-CASPT2 quantum-chemical method, and double-ζ basis sets (cc-pVDZ) were used to study 9 H-8-azaguanine and 8 H-8-azaguanine relaxation pathways. Several potential energy hypersurfaces were characterized by means of equilibrium geometries, surface crossings (conical intersections and singlet-triplet intersystem crossings), minimum energy paths, and linear interpolation in internal coordinates. The 9 H-8-azaguanine main photochemical event begins with the direct population of the 1(ππ* La) state, which evolves toward a conical intersection with the ground state after surmounting a small energy barrier, explaining why it is nonfluorescent. For 8 H-8-azaguanine, two relaxation mechanisms are possible, depending on the excitation energy. If the S1 1(ππ*) state is initially populated (lower-energy region), the system evolves barrierless to the S1 1(ππ*)min region, from where the excess energy is released. If the 1(ππ* La) state is populated (higher-energy radiation), the system will encounter conical intersections with the S2 1(nOπ*) and S1 1(ππ*) states before evolving to the 1(ππ* La)min region, from where a conical intersection with the ground state is accessible, favoring radiationless deactivation to the ground state. However, because a fraction of the population can be transferred from 1(ππ* La) to the S1 1(ππ*) state, emission from the S1 1(ππ*)min region is also expected, although weaker than it would be if the S1 1(ππ*) state were populated directly. Irrespective of the excitation energy, the emissive state is the same and a single fluorescence band is observed, with the strongest emission occurring upon excitation in the lower-energy region, as observed experimentally. Therefore, our computational study corroborates experimental results, attributing the emission of the neutral form of 8-azaguanine in solution to the presence of the minor 8 H-8-azaguanine tautomer, while the 9 H-8-azaguanine major tautomer is nonfluorescent.
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Affiliation(s)
| | - Antonio Carlos Borin
- Department of Fundamental Chemistry , Institute of Chemistry, University of São Paulo , Av. Prof. Lineu Prestes 748 , 05508-000 São Paulo , SP , Brazil
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8
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Böhnke H, Röttger K, Ingle RA, Marroux HJB, Bohnsack M, Orr-Ewing AJ, Temps F. Efficient intersystem crossing in 2-aminopurine riboside probed by femtosecond time-resolved transient vibrational absorption spectroscopy. Phys Chem Chem Phys 2018; 20:20033-20042. [DOI: 10.1039/c8cp02664e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The photophysical dynamics of 2-aminopurine, a fluorescent analogue of the canonical nucleobase adenine, has been studied by femtosecond transient vibrational absorption spectroscopy.
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Affiliation(s)
- Hendrik Böhnke
- Institute of Physical Chemistry
- Christian-Albrechts-University Kiel
- 24098 Kiel
- Germany
| | - Katharina Röttger
- Institute of Physical Chemistry
- Christian-Albrechts-University Kiel
- 24098 Kiel
- Germany
- School of Chemistry
| | | | | | - Mats Bohnsack
- Institute of Physical Chemistry
- Christian-Albrechts-University Kiel
- 24098 Kiel
- Germany
| | | | - Friedrich Temps
- Institute of Physical Chemistry
- Christian-Albrechts-University Kiel
- 24098 Kiel
- Germany
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9
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Valverde D, Vasconcelos Sanches de Araujo A, Carlos Borin A, Canuto S. Electronic structure and absorption spectra of fluorescent nucleoside analogues. Phys Chem Chem Phys 2017; 19:29354-29363. [PMID: 29075734 DOI: 10.1039/c7cp04885h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This work presents a systematic investigation of the electronic and conformational properties of five new fluorescent nucleobases belonging to the alphabet based on the isothiazole[4,3-d]pyrimidine molecule, very recently synthesized. This is of particular importance in the characterization of the main electronic aspects of these fluorescent nucleosides. The solvent effects of 1,4-dioxane and water were included combining the Sequential Monte Carlo/CASPT2 and the Free Energy Gradient (FEG) methods. For comparison, the Polarizable Continuum method was also used. The geometries of all compounds were optimized in solvent with the largest effects observed in water using the average solvent electrostatic configuration (ASEC) and the FEG approaches. Statistical analysis of the solute-solvent hydrogen bonds is performed and their effect on the absorption spectra analyzed. The dipole moments were calculated and the value obtained from the ASEC-FEG method in water follows the same trend as the natural canonical bases (adenine → uracil → guanine → cytosine). The theoretical results for the absorption spectra obtained from CASPT2(18,13) calculations using the geometries obtained with the ASEC-FEG procedure are in very good agreement with the experimental data. A detailed elucidation of the main aspects of the absorption spectra of the five new fluorescent nucleoside analogues is successfully attempted.
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Affiliation(s)
- Danillo Valverde
- Universidade de São Paulo, Instituto de Física, Rua do Matão 1371, São Paulo, SP CEP 05508-090, Brazil.
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10
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Martínez-Fernández L, Pepino AJ, Segarra-Martí J, Banyasz A, Garavelli M, Improta R. Computing the Absorption and Emission Spectra of 5-Methylcytidine in Different Solvents: A Test-Case for Different Solvation Models. J Chem Theory Comput 2016; 12:4430-9. [DOI: 10.1021/acs.jctc.6b00518] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- L. Martínez-Fernández
- Istituto di Biostrutture
e Bioimmagini, CNR, Via Mezzocannone
16, I-80134 Napoli, Italy
| | - A. J. Pepino
- Dipartimento
di Chimica “G. Ciamician”, Università di Bologna, Bologna, Italy
| | - J. Segarra-Martí
- Dipartimento
di Chimica “G. Ciamician”, Università di Bologna, Bologna, Italy
- École
Normale Supérieure de Lyon, CNRS, UMR 5182, Université de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07, France
| | - A. Banyasz
- LIDYL,
CEA, CNRS, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - M. Garavelli
- Dipartimento
di Chimica “G. Ciamician”, Università di Bologna, Bologna, Italy
- École
Normale Supérieure de Lyon, CNRS, UMR 5182, Université de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07, France
| | - R. Improta
- Istituto di Biostrutture
e Bioimmagini, CNR, Via Mezzocannone
16, I-80134 Napoli, Italy
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11
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2-aminopurine as a fluorescent probe of DNA conformation and the DNA–enzyme interface. Q Rev Biophys 2015; 48:244-79. [DOI: 10.1017/s0033583514000158] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AbstractNearly 50 years since its potential as a fluorescent base analogue was first recognized, 2-aminopurine (2AP) continues to be the most widely used fluorescent probe of DNA structure and the perturbation of that structure by interaction with enzymes and other molecules. In this review, we begin by considering the origin of the dramatic and intriguing difference in photophysical properties between 2AP and its structural isomer, adenine; although 2AP differs from the natural base only in the position of the exocyclic amine group, its fluorescence intensity is one thousand times greater. We then discuss the mechanism of interbase quenching of 2AP fluorescence in DNA, which is the basis of its use as a conformational probe but remains imperfectly understood. There are hundreds of examples in the literature of the use of changes in the fluorescence intensity of 2AP as the basis of assays of conformational change; however, in this review we will consider in detail only a few intensity-based studies. Our primary aim is to highlight the use of time-resolved fluorescence measurements, and the interpretation of fluorescence decay parameters, to explore the structure and dynamics of DNA. We discuss the salient features of the fluorescence decay of 2AP when incorporated in DNA and review the use of decay measurements in studying duplexes, single strands and other structures. We survey the use of 2AP as a probe of DNA-enzyme interaction and enzyme-induced distortion, focusing particularly on its use to study base flipping and the enhanced mechanistic insights that can be gained by a detailed analysis of the decay parameters, rather than merely monitoring changes in fluorescence intensity. Finally we reflect on the merits and shortcomings of 2AP and the prospects for its wider adoption as a fluorescence-decay-based probe.
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12
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Switching on the fluorescence of 2-aminopurine by site-selective microhydration. Nat Chem 2014; 6:989-93. [DOI: 10.1038/nchem.2086] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 09/11/2014] [Indexed: 11/08/2022]
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13
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14
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Toliautas S, Macernis M, Sulskus J, Valkunas L. Solvent effect on the photo-induced proton transfer in 2-(N-methyl-α-iminoethyl)-phenol. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2013.10.084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Lobsiger S, Sinha RK, Leutwyler S. Building Up Water-Wire Clusters: Isomer-Selective Ultraviolet and Infrared Spectra of Jet-Cooled 2-Aminopurine (H2O)n, n = 2 and 3. J Phys Chem B 2013; 117:12410-21. [DOI: 10.1021/jp407127c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Simon Lobsiger
- Department
of Chemistry and Biochemistry, University of Bern, Freiestrasse
3, CH-3012 Bern, Switzerland
- Department
of Chemistry, University of Virginia, McCormick Road, Charlottesville, Virginia 22904-4319, United States
| | - Rajeev K. Sinha
- Department
of Chemistry and Biochemistry, University of Bern, Freiestrasse
3, CH-3012 Bern, Switzerland
- Department
of Atomic and Molecular Physics, Manipal University, Manipal-576104, Karnataka, India
| | - Samuel Leutwyler
- Department
of Chemistry and Biochemistry, University of Bern, Freiestrasse
3, CH-3012 Bern, Switzerland
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16
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Abou-Zied OK. Effect of NH2 rotation on the fluorescence of 2-aminopurine in solution. J Photochem Photobiol A Chem 2013. [DOI: 10.1016/j.jphotochem.2013.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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17
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Minezawa N, Gordon MS. Optimizing conical intersections of solvated molecules: The combined spin-flip density functional theory/effective fragment potential method. J Chem Phys 2012; 137:034116. [DOI: 10.1063/1.4734314] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Orozco-González Y, Coutinho K, Canuto S. Excited state electronic polarization and reappraisal of the n ← π∗ emission of acetone in water. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.09.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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19
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20
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Serrano-Andrés L, Merchán M. Are the five natural DNA/RNA base monomers a good choice from natural selection? JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2009. [DOI: 10.1016/j.jphotochemrev.2008.12.001] [Citation(s) in RCA: 199] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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21
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Abstract
The accurate ab initio quantum chemical (QM) method multiconfigurational second-order perturbation (CASSPT2)/complete active space self-consistent field (CASSCF) has been used in conjunction with molecular mechanics (MM) procedures to compute molecular properties and photoinduced reactivity of DNA/RNA nucleobases (NABs) in isolation and within a realistic environment, in which the double helix strand, the aqueous media, and the external counterions are included. It is illustrated that the use of an MM model is helpful both to account for short- and long-range effects of the system surrounding the QM molecular core and to provide the proper structural constraints that allow more accurate QM geometry determinations.
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