101
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Oliver TAA. Recent advances in multidimensional ultrafast spectroscopy. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171425. [PMID: 29410844 PMCID: PMC5792921 DOI: 10.1098/rsos.171425] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/20/2017] [Indexed: 05/14/2023]
Abstract
Multidimensional ultrafast spectroscopies are one of the premier tools to investigate condensed phase dynamics of biological, chemical and functional nanomaterial systems. As they reach maturity, the variety of frequency domains that can be explored has vastly increased, with experimental techniques capable of correlating excitation and emission frequencies from the terahertz through to the ultraviolet. Some of the most recent innovations also include extreme cross-peak spectroscopies that directly correlate the dynamics of electronic and vibrational states. This review article summarizes the key technological advances that have permitted these recent advances, and the insights gained from new multidimensional spectroscopic probes.
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Affiliation(s)
- Thomas A. A. Oliver
- School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, UK
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102
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Segarra-Martí J, Jaiswal VK, Pepino AJ, Giussani A, Nenov A, Mukamel S, Garavelli M, Rivalta I. Two-dimensional electronic spectroscopy as a tool for tracking molecular conformations in DNA/RNA aggregates. Faraday Discuss 2018; 207:233-250. [DOI: 10.1039/c7fd00201g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A computational strategy to simulate two-dimensional electronic spectra (2DES) is introduced, which allows characterising ground state conformations of flexible nucleobase aggregates that play a crucial role in nucleic acid photochemistry.
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Affiliation(s)
- Javier Segarra-Martí
- Univ Lyon, Ens de Lyon, CNRS
- Université Claude Bernard Lyon 1
- Laboratoire de Chimie UMR 5182
- Lyon
- France
| | - Vishal K. Jaiswal
- Dipartimento di Chimica Industriale “Toso Montanari”
- Università di Bologna
- Italy
| | - Ana Julieta Pepino
- Dipartimento di Chimica Industriale “Toso Montanari”
- Università di Bologna
- Italy
| | - Angelo Giussani
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | - Artur Nenov
- Dipartimento di Chimica Industriale “Toso Montanari”
- Università di Bologna
- Italy
| | - Shaul Mukamel
- Department of Chemistry
- University of California
- Irvine
- USA
| | - Marco Garavelli
- Dipartimento di Chimica Industriale “Toso Montanari”
- Università di Bologna
- Italy
| | - Ivan Rivalta
- Univ Lyon, Ens de Lyon, CNRS
- Université Claude Bernard Lyon 1
- Laboratoire de Chimie UMR 5182
- Lyon
- France
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103
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Abstract
The response of nucleobases to UV radiation depends on structure in subtle ways, as revealed by gas-phase experiments.
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Affiliation(s)
- Samuel Boldissar
- Department of Chemistry and Biochemistry University of California Santa Barbara
- USA
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104
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Martinez-Fernandez L, Improta R. Photoactivated proton coupled electron transfer in DNA: insights from quantum mechanical calculations. Faraday Discuss 2018; 207:199-216. [DOI: 10.1039/c7fd00195a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The energetics of the two main proton coupled electron transfer processes that could occur in DNA are determined by means of time dependent-DFT calculations, using the M052X functional and the polarizable continuum model to include solvent effect.
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Affiliation(s)
| | - Roberto Improta
- Consiglio Nazionale delle Ricerche
- Istituto di Biostrutture e Bioimmagini
- 80136 Naples
- Italy
- LIDYL
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105
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Photorelaxation and Photorepair Processes in Nucleic and Amino Acid Derivatives. Molecules 2017; 22:molecules22122203. [PMID: 29231852 PMCID: PMC6149726 DOI: 10.3390/molecules22122203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 12/07/2017] [Accepted: 12/09/2017] [Indexed: 11/17/2022] Open
Abstract
Understanding the fundamental interaction between electromagnetic radiation and matter is essential for a large number of phenomena, with significance to civilization.[...].
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106
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Wang Q, Xie XY, Han J, Cui G. QM and QM/MM Studies on Excited-State Relaxation Mechanisms of Unnatural Bases in Vacuo and Base Pairs in DNA. J Phys Chem B 2017; 121:10467-10478. [DOI: 10.1021/acs.jpcb.7b09046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Qian Wang
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xiao-Ying Xie
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
| | - Juan Han
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ganglong Cui
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
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107
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Conti I, Martínez-Fernández L, Esposito L, Hofinger S, Nenov A, Garavelli M, Improta R. Multiple Electronic and Structural Factors Control Cyclobutane Pyrimidine Dimer and 6-4 Thymine-Thymine Photodimerization in a DNA Duplex. Chemistry 2017; 23:15177-15188. [PMID: 28809462 DOI: 10.1002/chem.201703237] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Indexed: 11/09/2022]
Abstract
The T-T photodimerization paths leading to the formation of cyclobutane pyrimidine dimer (CPD) and 6-4 pyrimidine pyrimidone (64-PP), the two main DNA photolesions, have been resolved for a T-T step in a DNA duplex by two complementary state-of-the-art quantum mechanical approaches: QM(CASPT2//CASSCF)/MM and TD-DFT/PCM. Based on the analysis of several different representative structures, we define a new-ensemble of cooperating geometrical and electronic factors (besides the distance between the reacting bonds) ruling T-T photodimerization in DNA. CPD is formed by a barrierless path on an exciton state delocalized over the two bases. Large interbase stacking and shift values, together with a small pseudorotation phase angle for T at the 3'-end, favor this reaction. The oxetane intermediate, leading to a 64-PP adduct, is formed on a singlet T→T charge-transfer state and is favored by a large interbase angle and slide values. A small energy barrier (<0.3 eV) is associated to this path, likely contributing to the smaller quantum yield observed for this process. Eventually, a clear directionality is always shown by the electronic excitation characterizing the singlet photoactive state driving the photodimerization process: an exciton that is more localized on T3 and a 5'-T→3'-T charge transfer for CPD and oxetane formation, respectively, thus calling for specific electronic constraints.
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Affiliation(s)
- Irene Conti
- Dipartimento di Chimica Industriale "T. Montanari", Università di Bologna, Viale Risorgimento 4, 40136, Bologna, Italy
| | | | - Luciana Esposito
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134, Napoli, Italy
| | - Siegfried Hofinger
- TU Wien, Zentraler Informatikdienst, Wiedner Hauptstrasse 8-10, 1040, Wien, Austria.,Department of Physics, Michigan Technological University, 1400 Townsend Drive, Houghton, MI, 49331-1295, USA
| | - Artur Nenov
- Dipartimento di Chimica Industriale "T. Montanari", Università di Bologna, Viale Risorgimento 4, 40136, Bologna, Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale "T. Montanari", Università di Bologna, Viale Risorgimento 4, 40136, Bologna, Italy
| | - Roberto Improta
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134, Napoli, Italy.,LIDYL, CEA, CNRS, Université Paris, Saclay, 91191, Gif-sur-Yvette, France
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108
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Kowalewski M, Fingerhut BP, Dorfman KE, Bennett K, Mukamel S. Simulating Coherent Multidimensional Spectroscopy of Nonadiabatic Molecular Processes: From the Infrared to the X-ray Regime. Chem Rev 2017; 117:12165-12226. [DOI: 10.1021/acs.chemrev.7b00081] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Markus Kowalewski
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Benjamin P. Fingerhut
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
| | - Konstantin E. Dorfman
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Kochise Bennett
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Shaul Mukamel
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
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109
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Ashwood B, Ortiz-Rodríguez LA, Crespo-Hernández CE. Excited-State Dynamics in O 6-Methylguanosine: Impact of O 6-Methylation on the Relaxation Mechanism of Guanine Monomers. J Phys Chem Lett 2017; 8:4380-4385. [PMID: 28850232 DOI: 10.1021/acs.jpclett.7b02090] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Absorption of ultraviolet radiation by DNA bases results in ultrafast internal conversion to the ground state, which minimizes photodamage. However, exogenous and endogenous alkylating agents present in the cellular environment can methylate the nucleobases in DNA. In particular, methylation of guanosine at the O6 position in DNA leads to the formation of the O6-methylguanosine adduct, which may alter the photostability of DNA. This contribution demonstrates that O6-methylation of guanosine red shifts its ground-state absorption spectrum and slows down the rate of internal conversion to the ground state by ∼40-fold in aqueous solution. The 40-fold decrease in the rate of excited-state decay increases the probability of photodamage within cellular DNA. It is proposed that the longer decay lifetime corresponds to relaxation of the excited-state population in O6-methylguanosine along a C6-puckered reaction coordinate in the 1ππ*(La) potential energy surface that runs parallel to an ultrafast internal conversion pathway along a C2-puckered coordinate.
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Affiliation(s)
- Brennan Ashwood
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Luis A Ortiz-Rodríguez
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Carlos E Crespo-Hernández
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University , Cleveland, Ohio 44106, United States
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110
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Excited State Dynamics of Cold Protonated Cytosine Tautomers: Characterization of Charge Transfer, Intersystem Crossing, and Internal Conversion Processes. J Phys Chem A 2017; 121:6429-6439. [DOI: 10.1021/acs.jpca.7b06423] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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111
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Martinez-Fernandez L, Banyasz A, Esposito L, Markovitsi D, Improta R. UV-induced damage to DNA: effect of cytosine methylation on pyrimidine dimerization. Signal Transduct Target Ther 2017; 2:17021. [PMID: 29263920 PMCID: PMC5661629 DOI: 10.1038/sigtrans.2017.21] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 01/24/2017] [Accepted: 03/30/2017] [Indexed: 11/09/2022] Open
Abstract
Methylation/demethylation of cytosine plays an important role in epigenetic signaling, the reversibility of epigenetic modifications offering important opportunities for targeted therapies. Actually, methylated sites have been correlated with mutational hotspots detected in skin cancers. The present brief review discusses the physicochemical parameters underlying the specific ultraviolet-induced reactivity of methylated cytosine. It focuses on dimerization reactions giving rise to cyclobutane pyrimidine dimers and pyrimidine (6–4) pyrimidone adducts. According to recent studies, four conformational and electronic factors that are affected by cytosine methylation may control these reactions: the red-shift of the absorption spectrum, the lengthening of the excited state lifetime, changes in the sugar puckering modifying the stacking between reactive pyrimidines and an increase in the rigidity of duplexes favoring excitation energy transfer toward methylated pyrimidines.
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Affiliation(s)
| | - Akos Banyasz
- LIDYL, CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
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112
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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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113
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Jian Y, Maximowitsch E, Liu D, Adhikari S, Li L, Domratcheva T. Indications of 5' to 3' Interbase Electron Transfer as the First Step of Pyrimidine Dimer Formation Probed by a Dinucleotide Analog. Chemistry 2017; 23:7526-7537. [PMID: 28370554 DOI: 10.1002/chem.201700045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Indexed: 12/12/2022]
Abstract
Pyrimidine dimers are the most common DNA lesions generated under UV radiation. To reveal the molecular mechanisms behind their formation, it is of significance to reveal the roles of each pyrimidine residue. We thus replaced the 5'-pyrimidine residue with a photochemically inert xylene moiety (X). The electron-rich X can be readily oxidized but not reduced, defining the direction of interbase electron transfer (ET). Irradiation of the XpT dinucleotide under 254 nm UV light generates two major photoproducts: a pyrimidine (6-4) pyrimidone analog (6-4PP) and an analog of the so-called spore photoproduct (SP). Both products are formed by reaction at C4=O of the photo-excited 3'-thymidine (T), which indicates that excitation of a single "driver" residue is sufficient to trigger pyrimidine dimerization. Our quantum-chemical calculations demonstrated that photo-excited 3'-T accepts an electron from 5'-X. The resulting charge-separated radical pair lowers its energy upon formation of interbase covalent bonds, eventually yielding 6-4PP and SP.
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Affiliation(s)
- Yajun Jian
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, Indiana, 46202, USA.,School of Chemistry & Chemical Engineering, Shaanxi Normal University (SNNU), No. 620, West Chang'an Avenue, Xi'an, Shaanxi, 710119, P. R. China
| | - Egle Maximowitsch
- Department of Biomolecular Mechanisms, Max-Planck Institute for Medical Research, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Degang Liu
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, Indiana, 46202, USA
| | - Surya Adhikari
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, Indiana, 46202, USA
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, Indiana, 46202, USA.,Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, 46202, USA
| | - Tatiana Domratcheva
- Department of Biomolecular Mechanisms, Max-Planck Institute for Medical Research, Jahnstrasse 29, 69120, Heidelberg, Germany
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114
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Xie B, Cui G, Fang WH. Multiple-State Nonadiabatic Dynamics Simulation of Photoisomerization of Acetylacetone with the Direct ab Initio QTMF Approach. J Chem Theory Comput 2017; 13:2717-2729. [DOI: 10.1021/acs.jctc.7b00153] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Binbin Xie
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ganglong Cui
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
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115
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Röttger K, Marroux HJB, Chemin AFM, Elsdon E, Oliver TAA, Street STG, Henderson AS, Galan MC, Orr-Ewing AJ, Roberts GM. Is UV-Induced Electron-Driven Proton Transfer Active in a Chemically Modified A·T DNA Base Pair? J Phys Chem B 2017; 121:4448-4455. [PMID: 28394602 DOI: 10.1021/acs.jpcb.7b02679] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Transient electronic and vibrational absorption spectroscopies have been used to investigate whether UV-induced electron-driven proton transfer (EDPT) mechanisms are active in a chemically modified adenine-thymine (A·T) DNA base pair. To enhance the fraction of biologically relevant Watson-Crick (WC) hydrogen-bonding motifs and eliminate undesired Hoogsteen structures, a chemically modified derivative of A was synthesized, 8-(tert-butyl)-9-ethyladenine (8tBA). Equimolar solutions of 8tBA and silyl-protected T nucleosides in chloroform yield a mixture of WC pairs, reverse WC pairs, and residual monomers. Unlike previous transient absorption studies of WC guanine-cytosine (G·C) pairs, no clear spectroscopic or kinetic evidence was identified for the participation of EDPT in the excited-state relaxation dynamics of 8tBA·T pairs, although ultrafast (sub-100 fs) EDPT cannot be discounted. Monomer-like dynamics are proposed to dominate in 8tBA·T.
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Affiliation(s)
- Katharina Röttger
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Hugo J B Marroux
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Arsène F M Chemin
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Emma Elsdon
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Thomas A A Oliver
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Steven T G Street
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | | | - M Carmen Galan
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Andrew J Orr-Ewing
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Gareth M Roberts
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
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116
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Small RNA-mediated repair of UV-induced DNA lesions by the DNA DAMAGE-BINDING PROTEIN 2 and ARGONAUTE 1. Proc Natl Acad Sci U S A 2017; 114:E2965-E2974. [PMID: 28325872 DOI: 10.1073/pnas.1618834114] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
As photosynthetic organisms, plants need to prevent irreversible UV-induced DNA lesions. Through an unbiased, genome-wide approach, we have uncovered a previously unrecognized interplay between Global Genome Repair and small interfering RNAs (siRNAs) in the recognition of DNA photoproducts, prevalently in intergenic regions. Genetic and biochemical approaches indicate that, upon UV irradiation, the DNA DAMAGE-BINDING PROTEIN 2 (DDB2) and ARGONAUTE 1 (AGO1) of Arabidopsis thaliana form a chromatin-bound complex together with 21-nt siRNAs, which likely facilitates recognition of DNA damages in an RNA/DNA complementary strand-specific manner. The biogenesis of photoproduct-associated siRNAs involves the noncanonical, concerted action of RNA POLYMERASE IV, RNA-DEPENDENT RNA POLYMERASE-2, and DICER-LIKE-4. Furthermore, the chromatin association/dissociation of the DDB2-AGO1 complex is under the control of siRNA abundance and DNA damage signaling. These findings reveal unexpected nuclear functions for DCL4 and AGO1, and shed light on the interplay between small RNAs and DNA repair recognition factors at damaged sites.
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117
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Hu J, Adar S. The Cartography of UV-induced DNA Damage Formation and DNA Repair. Photochem Photobiol 2017; 93:199-206. [PMID: 27861959 DOI: 10.1111/php.12668] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 09/23/2016] [Indexed: 12/29/2022]
Abstract
DNA damage presents a barrier to DNA-templated biochemical processes, including gene expression and faithful DNA replication. Compromised DNA repair leads to mutations, enhancing the risk for genetic diseases and cancer development. Conventional experimental approaches to study DNA damage required a researcher to choose between measuring bulk damage over the entire genome, with little or no resolution regarding a specific location, and obtaining data specific to a locus of interest, without a global perspective. Recent advances in high-throughput genomic tools overcame these limitations and provide high-resolution measurements simultaneously across the genome. In this review, we discuss the available methods for measuring DNA damage and their repair, focusing on genomewide assays for pyrimidine photodimers, the major types of damage induced by ultraviolet irradiation. These new genomic assays will be a powerful tool in identifying key components of genome stability and carcinogenesis.
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Affiliation(s)
- Jinchuan Hu
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Sheera Adar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC
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118
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Martínez-Fernández L, Granucci G, Pollum M, Crespo-Hernández CE, Persico M, Corral I. Decoding the Molecular Basis for the Population Mechanism of the Triplet Phototoxic Precursors in UVA Light-Activated Pyrimidine Anticancer Drugs. Chemistry 2017; 23:2619-2627. [DOI: 10.1002/chem.201604543] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Lara Martínez-Fernández
- Departamento de Química; Universidad Autónoma de Madrid; 28049 Cantoblanco, Madrid Spain
- Current address: Istituto di Biostrutture e Bioimmagini; Consiglio delle Ricerche; 80134 Napoli Italy
| | - Giovanni Granucci
- Dipartimento di Chimica e Chimica Industriale; Università di Pisa; v. G. Moruzzi 3 56124 Pisa Italy
| | - Marvin Pollum
- Department of Chemistry and Center for Chemical Dynamics; Case Western Reserve University; 10900 Euclid Avenue Cleveland OH 44106 USA
| | - Carlos E. Crespo-Hernández
- Department of Chemistry and Center for Chemical Dynamics; Case Western Reserve University; 10900 Euclid Avenue Cleveland OH 44106 USA
| | - Maurizio Persico
- Dipartimento di Chimica e Chimica Industriale; Università di Pisa; v. G. Moruzzi 3 56124 Pisa Italy
| | - Inés Corral
- Departamento de Química; Universidad Autónoma de Madrid; 28049 Cantoblanco, Madrid Spain
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119
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Wu X, Karsili TNV, Domcke W. Role of Electron-Driven Proton-Transfer Processes in the Ultrafast Deactivation of Photoexcited Anionic 8-oxoGuanine-Adenine and 8-oxoGuanine-Cytosine Base Pairs. Molecules 2017; 22:molecules22010135. [PMID: 28098833 PMCID: PMC6155867 DOI: 10.3390/molecules22010135] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 12/28/2016] [Accepted: 01/10/2017] [Indexed: 11/16/2022] Open
Abstract
It has been reported that 8-oxo-7,8-dihydro-guanosine (8-oxo-G), which is the main product of oxidative damage of DNA, can repair cyclobutane pyrimidine dimer (CPD) lesions when incorporated into DNA or RNA strands in proximity to such lesions. It has therefore been suggested that the 8-oxo-G nucleoside may have been a primordial precursor of present-day flavins in DNA or RNA repair. Because the electron transfer leading to the splitting of a thymine-thymine pair in a CPD lesion occurs in the photoexcited state, a reasonably long excited-state lifetime of 8-oxo-G is required. The neutral (protonated) form of 8-oxo-G exhibits a very short (sub-picosecond) intrinsic excited-state lifetime which is unfavorable for repair. It has therefore been argued that the anionic (deprotonated) form of 8-oxo-G, which exhibits a much longer excited-state lifetime, is more likely to be a suitable cofactor for DNA repair. Herein, we have investigated the exited-state quenching mechanisms in the hydrogen-bonded complexes of deprotonated 8-oxo-G- with adenine (A) and cytosine (C) using ab initio wave-function-based electronic-structure calculations. The calculated reaction paths and potential-energy profiles reveal the existence of barrierless electron-driven inter-base proton-transfer reactions which lead to low-lying S₁/S₀ conical intersections. The latter can promote ultrafast excited-state deactivation of the anionic base pairs. While the isolated deprotonated 8-oxo-G- nucleoside may have been an efficient primordial repair cofactor, the excited states of the 8-oxo-G--A and 8-oxo-G--C base pairs are likely too short-lived to be efficient electron-transfer repair agents.
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Affiliation(s)
- Xiuxiu Wu
- Department of Chemistry, Technische Universitat Munchen, Lichtenbergstr. 4, Garching D-85747, Germany.
| | - Tolga N V Karsili
- Department of Chemistry, Temple University, 130 Beury Hall, 1901 N. 13th St., Philadelphia, PA 19122, USA.
| | - Wolfgang Domcke
- Department of Chemistry, Technische Universitat Munchen, Lichtenbergstr. 4, Garching D-85747, Germany.
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120
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Saha S, Quiney HM. Solvent effects on the excited state characteristics of adenine–thymine base pairs. RSC Adv 2017. [DOI: 10.1039/c7ra03244g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
A systematic analysis of the excited state characteristics of the DNA base pair adenine–thymine in stacked and Watson–Crick hydrogen bonded configurations has been carried out in this study.
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Affiliation(s)
- S. Saha
- ARC Centre of Excellence for Advanced Molecular Imaging
- Theoretical Condensed Matter Physics Group
- School of Physics
- The University of Melbourne
- Australia
| | - H. M. Quiney
- ARC Centre of Excellence for Advanced Molecular Imaging
- Theoretical Condensed Matter Physics Group
- School of Physics
- The University of Melbourne
- Australia
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121
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Xie BB, Wang Q, Guo WW, Cui G. The excited-state decay mechanism of 2,4-dithiothymine in the gas phase, microsolvated surroundings, and aqueous solution. Phys Chem Chem Phys 2017; 19:7689-7698. [DOI: 10.1039/c7cp00478h] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
We have employed computational methods to systematically explore the excited-state decay mechanism of 2,4-dithiothymine.
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Affiliation(s)
- Bin-Bin Xie
- Key Laboratory of Theoretical and Computational Photochemistry
- Ministry of Education
- College of Chemistry
- Beijing Normal University
- Beijing 100875
| | - Qian Wang
- Key Laboratory of Theoretical and Computational Photochemistry
- Ministry of Education
- College of Chemistry
- Beijing Normal University
- Beijing 100875
| | - Wei-Wei Guo
- Key Laboratory of Theoretical and Computational Photochemistry
- Ministry of Education
- College of Chemistry
- Beijing Normal University
- Beijing 100875
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry
- Ministry of Education
- College of Chemistry
- Beijing Normal University
- Beijing 100875
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122
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Segarra-Martí J, Francés-Monerris A, Roca-Sanjuán D, Merchán M. Assessment of the Potential Energy Hypersurfaces in Thymine within Multiconfigurational Theory: CASSCF vs. CASPT2. Molecules 2016; 21:molecules21121666. [PMID: 27918489 PMCID: PMC6274573 DOI: 10.3390/molecules21121666] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 11/16/2022] Open
Abstract
The present study provides new insights into the topography of the potential energy hypersurfaces (PEHs) of the thymine nucleobase in order to rationalize its main ultrafast photochemical decay paths by employing two methodologies based on the complete active space self-consistent field (CASSCF) and the complete active space second-order perturbation theory (CASPT2) methods: (i) CASSCF optimized structures and energies corrected with the CASPT2 method at the CASSCF geometries and (ii) CASPT2 optimized geometries and energies. A direct comparison between these strategies is drawn, yielding qualitatively similar results within a static framework. A number of analyses are performed to assess the accuracy of these different computational strategies under study based on a variety of numerical thresholds and optimization methods. Several basis sets and active spaces have also been calibrated to understand to what extent they can influence the resulting geometries and subsequent interpretation of the photochemical decay channels. The study shows small discrepancies between CASSCF and CASPT2 PEHs, displaying a shallow planar or twisted 1(ππ*) minimum, respectively, and thus featuring a qualitatively similar scenario for supporting the ultrafast bi-exponential deactivation registered in thymine upon UV-light exposure. A deeper knowledge of the PEHs at different levels of theory provides useful insight into its correct characterization and subsequent interpretation of the experimental observations. The discrepancies displayed by the different methods studied here are then discussed and framed within their potential consequences in on-the-fly non-adiabatic molecular dynamics simulations, where qualitatively diverse outcomes are expected.
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Affiliation(s)
- Javier Segarra-Martí
- Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain.
- Present Address: Laboratoire de Chimie UMR 5182, École Normale Supérieure de Lyon, CNRS, Université de Lyon, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France.
| | - Antonio Francés-Monerris
- Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain.
| | - Daniel Roca-Sanjuán
- Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain.
| | - Manuela Merchán
- Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain.
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123
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Mendieta-Moreno JI, Trabada DG, Mendieta J, Lewis JP, Gómez-Puertas P, Ortega J. Quantum Mechanics/Molecular Mechanics Free Energy Maps and Nonadiabatic Simulations for a Photochemical Reaction in DNA: Cyclobutane Thymine Dimer. J Phys Chem Lett 2016; 7:4391-4397. [PMID: 27768300 DOI: 10.1021/acs.jpclett.6b02168] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The absorption of ultraviolet radiation by DNA may result in harmful genetic lesions that affect DNA replication and transcription, ultimately causing mutations, cancer, and/or cell death. We analyze the most abundant photochemical reaction in DNA, the cyclobutane thymine dimer, using hybrid quantum mechanics/molecular mechanics (QM/MM) techniques and QM/MM nonadiabatic molecular dynamics. We find that, due to its double helix structure, DNA presents a free energy barrier between nonreactive and reactive conformations leading to the photolesion. Moreover, our nonadiabatic simulations show that most of the photoexcited reactive conformations return to standard B-DNA conformations after an ultrafast nonradiative decay to the ground state. This work highlights the importance of dynamical effects (free energy, excited-state dynamics) for the study of photochemical reactions in biological systems.
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Affiliation(s)
- Jesús I Mendieta-Moreno
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , ES-28049 Madrid, Spain
- Molecular Modelling Group, Center of Molecular Biology Severo Ochoa (CSIC-UAM) , ES-28049 Madrid, Spain
| | - Daniel G Trabada
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , ES-28049 Madrid, Spain
| | - Jesús Mendieta
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , ES-28049 Madrid, Spain
- Molecular Modelling Group, Center of Molecular Biology Severo Ochoa (CSIC-UAM) , ES-28049 Madrid, Spain
- Departamento de Biotecnología, Universidad Francisco de Vitoria , ctra. Pozuelo-Majadahonda, km 1,800, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - James P Lewis
- Department of Physics, West Virginia University , Morgantown, West Virginia 26506-6315, United States
| | - Paulino Gómez-Puertas
- Molecular Modelling Group, Center of Molecular Biology Severo Ochoa (CSIC-UAM) , ES-28049 Madrid, Spain
| | - José Ortega
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , ES-28049 Madrid, Spain
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124
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Barlev A, Sekhon GS, Bennet AJ, Sen D. DNA Repair by DNA: The UV1C DNAzyme Catalyzes Photoreactivation of Cyclobutane Thymine Dimers in DNA More Effectively than Their de Novo Formation. Biochemistry 2016; 55:6010-6018. [PMID: 27726378 DOI: 10.1021/acs.biochem.6b00951] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
UV1C, a 42-nt DNA oligonucleotide, is a deoxyribozyme (DNAzyme) that optimally uses 305 nm wavelength light to catalyze photoreactivation of a cyclobutane thymine dimer placed within a gapped, unnatural DNA substrate, TDP. Herein we show that UV1C is also capable of photoreactivating thymine dimers within an authentic single-stranded DNA substrate, LDP. This bona fide UV1C substrate enables, for the first time, investigation of whether UV1C catalyzes only photoreactivation or also the de novo formation of thymine dimers. Single-turnover experiments carried out with LDP and UV1C, relative to control experiments with LDP alone in single-stranded and double-stranded contexts, show that while UV1C does modestly promote thymine dimer formation, its major activity is indeed photoreactivation. Distinct photostationary states are reached for LDP in its three contexts: as a single strand, as a constituent of a double-helix, and as a 1:1 complex with UV1C. The above results on the cofactor-independent photoreactivation capabilities of a catalytic DNA reinforce a series of recent, unexpected reports that purely nucleotide-based photoreactivation is also operational within conventional double-helical DNA.
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Affiliation(s)
| | - Gurpreet S Sekhon
- Canary Center at Stanford for Cancer Early Detection, Department of Radiology, Stanford University, School of Medicine , Palo Alto, California 94304, United States
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125
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Ashwood B, Pollum M, Crespo-Hernández CE. Can a Six-Letter Alphabet Increase the Likelihood of Photochemical Assault to the Genetic Code? Chemistry 2016; 22:16648-16656. [PMID: 27723147 DOI: 10.1002/chem.201602160] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Indexed: 12/21/2022]
Abstract
In 2014, two unnatural nucleosides, d5SICS and dNaM, were shown to selectively base pair and replicate with high fidelity in a modified strain of E. coli, thus effectively expanding its genetic alphabet from four to six letters. More recently, a significant reduction in cell proliferation was reported in cells cultured with d5SICS, and putatively with dNaM, upon exposure to brief periods of near-visible radiation. The photosensitizing properties of the lowest-energy excited triplet state of both d5SICS and dNaM were implicated in their cytotoxicity. Importantly, however, the excited-state mechanisms by which near-visible excitation populates the triplet states of d5SICS and dNaM are currently unknown. In this study, steady-state and time-resolved spectroscopies are combined with quantum-chemical calculations in order to reveal the excited-state relaxation mechanisms leading to efficient population of the triplet states in these unnatural nucleosides in solution. It is shown that excitation of d5SICS or dNaM with near-visible light leads overwhelmingly to ultrafast population of their triplet states on the femtosecond time scale. The results presented in this work lend strong support to the proposal that photoexcitation of these unnatural nucleosides can accelerate oxidatively generated damage to DNA and other biomolecules within the cellular environment.
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Affiliation(s)
- Brennan Ashwood
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Marvin Pollum
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Carlos E Crespo-Hernández
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio, 44106, USA.
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126
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Pollum M, Ashwood B, Jockusch S, Lam M, Crespo-Hernández CE. Unintended Consequences of Expanding the Genetic Alphabet. J Am Chem Soc 2016; 138:11457-60. [DOI: 10.1021/jacs.6b06822] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Marvin Pollum
- Department
of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Brennan Ashwood
- Department
of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Steffen Jockusch
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Minh Lam
- Department
of Dermatology, Case Western Reserve School of Medicine, Cleveland, Ohio 44106, United States
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127
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Beckstead AA, Zhang Y, de Vries MS, Kohler B. Life in the light: nucleic acid photoproperties as a legacy of chemical evolution. Phys Chem Chem Phys 2016; 18:24228-38. [PMID: 27539809 DOI: 10.1039/c6cp04230a] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Photophysical investigations of the canonical nucleobases that make up DNA and RNA during the past 15 years have revealed that excited states formed by the absorption of UV radiation decay with subpicosecond lifetimes (i.e., <10(-12) s). Ultrashort lifetimes are a general property of absorbing sunscreen molecules, suggesting that the nucleobases are molecular survivors of a harsh UV environment. Encoding the genome using photostable building blocks is an elegant solution to the threat of photochemical damage. Ultrafast excited-state deactivation strongly supports the hypothesis that UV radiation played a major role in shaping molecular inventories on the early Earth before the emergence of life and the subsequent development of a protective ozone shield. Here, we review the general physical and chemical principles that underlie the photostability, or "UV hardiness", of modern nucleic acids and discuss the possible implications of these findings for prebiotic chemical evolution. In RNA and DNA strands, much longer-lived excited states are observed, which at first glance appear to increase the risk of photochemistry. It is proposed that the dramatically different photoproperties that emerge from assemblies of photostable building blocks may explain the transition from a world of molecular survival to a world in which energy-rich excited electronic states were eventually tamed for biological purposes such as energy transduction, signaling, and repair of the genetic machinery.
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Affiliation(s)
- Ashley A Beckstead
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717-3400, USA.
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128
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Abstract
Sunlight's ultraviolet wavelengths induce cyclobutane pyrimidine dimers (CPDs), which then cause mutations that lead to melanoma or to cancers of skin keratinocytes. In pigmented melanocytes, we found that CPDs arise both instantaneously and for hours after UV exposure ends. Remarkably, the CPDs arising in the dark originate by a novel pathway that resembles bioluminescence but does not end in light: First, UV activates the enzymes nitric oxide synthase (NOS) and NADPH oxidase (NOX), which generate the radicals nitric oxide (NO) and superoxide (O2(-)); these combine to form the powerful oxidant peroxynitrite (ONOO(-)). A fragment of the skin pigment melanin is then oxidized, exciting an electron to an energy level so high that it is rarely seen in biology. This process of chemically exciting electrons, termed "chemiexcitation", is used by fireflies to generate light but it had never been seen in mammalian cells. In melanocytes, the energy transfers radiationlessly to DNA, inducing CPDs. Chemiexcitation is a new source of genome instability, and it calls attention to endogenous mechanisms of genome maintenance that prevent electronic excitation or dissipate the energy of excited states. Chemiexcitation may also trigger pathogenesis in internal tissues because the same chemistry should arise wherever superoxide and nitric oxide arise near cells that contain melanin.
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Affiliation(s)
- Sanjay Premi
- Department of Therapeutic Radiology, Yale University School of Medicine, 333 Cedar St./HRT 213, New Haven, CT 06520-8040, USA.
| | - Douglas E Brash
- Department of Therapeutic Radiology, Yale University School of Medicine, 333 Cedar St./HRT 213, New Haven, CT 06520-8040, USA; Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT 06520-8040 USA.
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129
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Lobsiger S, Etinski M, Blaser S, Frey HM, Marian C, Leutwyler S. Intersystem crossing rates of S1 state keto-amino cytosine at low excess energy. J Chem Phys 2016; 143:234301. [PMID: 26696056 DOI: 10.1063/1.4937375] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The amino-keto tautomer of supersonic jet-cooled cytosine undergoes intersystem crossing (ISC) from the v = 0 and low-lying vibronic levels of its S1((1)ππ(∗)) state. We investigate these ISC rates experimentally and theoretically as a function of S1 state vibrational excess energy Eexc. The S1 vibronic levels are pumped with a ∼5 ns UV laser, the S1 and triplet state ion signals are separated by prompt or delayed ionization with a second UV laser pulse. After correcting the raw ISC yields for the relative S1 and T1 ionization cross sections, we obtain energy dependent ISC quantum yields QISC (corr)=1%-5%. These are combined with previously measured vibronic state-specific decay rates, giving ISC rates kISC = 0.4-1.5 ⋅ 10(9) s(-1), the corresponding S1⇝S0 internal conversion (IC) rates are 30-100 times larger. Theoretical ISC rates are computed using SCS-CC2 methods, which predict rapid ISC from the S1; v = 0 state with kISC = 3 ⋅ 10(9) s(-1) to the T1((3)ππ(∗)) triplet state. The surprisingly high rate of this El Sayed-forbidden transition is caused by a substantial admixture of (1)nOπ(∗) character into the S1((1)ππ(∗)) wave function at its non-planar minimum geometry. The combination of experiment and theory implies that (1) below Eexc = 550 cm(-1) in the S1 state, S1⇝S0 internal conversion dominates the nonradiative decay with kIC ≥ 2 ⋅ 10(10) s(-1), (2) the calculated S1⇝T1 ((1)ππ(∗)⇝(3)ππ(∗)) ISC rate is in good agreement with experiment, (3) being El-Sayed forbidden, the S1⇝T1 ISC is moderately fast (kISC = 3 ⋅ 10(9) s(-1)), and not ultrafast, as claimed by other calculations, and (4) at Eexc ∼ 550 cm(-1) the IC rate increases by ∼50 times, probably by accessing the lowest conical intersection (the C5-twist CI) and thereby effectively switching off the ISC decay channels.
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Affiliation(s)
- Simon Lobsiger
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Mihajlo Etinski
- Fakultet za Fizičku Hemiju, Univerzitet u Beogradu, Studentski Trg 12-16, SRB-11000 Beograd, Serbia
| | - Susan Blaser
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Hans-Martin Frey
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Christel Marian
- Institut für Theoretische Chemie und Computerchemie, Heinrich-Heine Universität, Universitätsstrasse 1, D-40225 Düsseldorf, Germany
| | - Samuel Leutwyler
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
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130
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Bull JN, West CW, Verlet JRR. Ultrafast dynamics of formation and autodetachment of a dipole-bound state in an open-shell π-stacked dimer anion. Chem Sci 2016; 7:5352-5361. [PMID: 30155188 PMCID: PMC6020752 DOI: 10.1039/c6sc01062h] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/23/2016] [Indexed: 12/15/2022] Open
Abstract
Isolated π-stacked dimer radical anions present the simplest model of an excess electron in a π-stacked environment. Here, frequency-, angle-, and time-resolved photoelectron imaging together with electronic structure calculations have been used to characterise the π-stacked coenzyme Q0 dimer radical anion and its exited state dynamics. In the ground electronic state, the excess electron is localised on one monomer with a planar para-quinone ring, which is solvated by the second monomer in which carbonyl groups are bent out of the para-quinone ring plane. Through the π-stacking interaction, the dimer anion exhibits a number of charge-transfer (intermolecular) valence-localised resonances situated in the detachment continuum that undergo efficient internal conversion to a cluster dipole-bound state (DBS) on a ∼60 fs timescale. In turn, the DBS undergoes vibration-mediated autodetachment on a 2.0 ± 0.2 ps timescale. Experimental vibrational structure and supporting calculations assign the intermolecular dynamics to be facilitated by vibrational wagging modes of the carbonyl groups on the non-planar monomer. At photon energies ∼0.6-1.0 eV above the detachment threshold, a competition between photoexcitation of an intermolecular resonance leading to the DBS, and photoexcitation of an intramolecular resonance leading to monomer-like dynamics further illustrates the π-stacking specific dynamics. Overall, this study provides the first direct observation of both internal conversion of resonances into a DBS, and characterisation of a vibration-mediated autodetachment in real-time.
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Affiliation(s)
- James N Bull
- Department of Chemistry , Durham University , South Road , Durham DH1 3LE , UK .
| | - Christopher W West
- Department of Chemistry , Durham University , South Road , Durham DH1 3LE , UK .
| | - Jan R R Verlet
- Department of Chemistry , Durham University , South Road , Durham DH1 3LE , UK .
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131
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Banyasz A, Esposito L, Douki T, Perron M, Lepori C, Improta R, Markovitsi D. Effect of C5-Methylation of Cytosine on the UV-Induced Reactivity of Duplex DNA: Conformational and Electronic Factors. J Phys Chem B 2016; 120:4232-42. [PMID: 27075054 DOI: 10.1021/acs.jpcb.6b03340] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
C5-methylation of cytosines is strongly correlated with UV-induced mutations detected in skin cancers. Mutational hot-spots appearing at TCG sites are due to the formation of pyrimidine cyclobutane dimers (CPDs). The present study, performed for the model DNA duplex (TCGTA)3·(TACGA)3 and the constitutive single strands, examines the factors underlying the effect of C5-methylation on pyrimidine dimerization at TCG sites. This effect is quantified for the first time by quantum yields ϕ. They were determined following irradiation at 255, 267, and 282 nm and subsequent photoproduct analysis using HPLC coupled to mass spectrometry. C5-methylation leads to an increase of the CPD quantum yield up to 80% with concomitant decrease of that of pyrimidine(6-4) pyrimidone adducts (64PPs) by at least a factor of 3. The obtained ϕ values cannot be explained only by the change of the cytosine absorption spectrum upon C5-methylation. The conformational and electronic factors that may affect the dimerization reaction are discussed in light of results obtained by fluorescence spectroscopy, molecular dynamics simulations, and quantum mechanical calculations. Thus, it appears that the presence of an extra methyl on cytosine affects the sugar puckering, thereby enhancing conformations of the TC step that are prone to CPD formation but less favorable to 64PPs. In addition, C5-methylation diminishes the amplitude of conformational motions in duplexes; in the resulting stiffer structure, ππ* excitations may be transferred from initially populated exciton states to reactive pyrimidines giving rise to CPDs.
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Affiliation(s)
- Akos Banyasz
- LIDYL, CEA, CNRS, Université Paris Saclay, F-91191 Gif-sur-Yvette, France
| | | | - Thierry Douki
- Université Grenoble Alpes, INAC, LCIB, LAN & CEA, INAC, SCIB, LANF-38000 Grenoble, France
| | - Marion Perron
- LIDYL, CEA, CNRS, Université Paris Saclay, F-91191 Gif-sur-Yvette, France
| | - Clément Lepori
- LIDYL, CEA, CNRS, Université Paris Saclay, F-91191 Gif-sur-Yvette, France
| | - Roberto Improta
- Istituto Biostrutture e Bioimmagini - CNR , 80134 Napoli, Italy
| | - Dimitra Markovitsi
- LIDYL, CEA, CNRS, Université Paris Saclay, F-91191 Gif-sur-Yvette, France
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132
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Carpenter BK, Harvey JN, Orr-Ewing AJ. The Study of Reactive Intermediates in Condensed Phases. J Am Chem Soc 2016; 138:4695-705. [DOI: 10.1021/jacs.6b01761] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Barry K. Carpenter
- School
of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, U.K
| | - Jeremy N. Harvey
- Department
of Chemistry, KU Leuven, Celestijnen Laan 200F, B-3001 Heverlee, Belgium
| | - Andrew J. Orr-Ewing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
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133
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Blaser S, Trachsel MA, Lobsiger S, Wiedmer T, Frey HM, Leutwyler S. Gas-Phase Cytosine and Cytosine-N1-Derivatives Have 0.1-1 ns Lifetimes Near the S1 State Minimum. J Phys Chem Lett 2016; 7:752-757. [PMID: 26863095 DOI: 10.1021/acs.jpclett.6b00017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ultraviolet radiative damage to DNA is inefficient because of the ultrafast S1 ⇝ S0 internal conversion of its nucleobases. Using picosecond pump-ionization delay measurements, we find that the S1((1)ππ*) state vibrationless lifetime of gas-phase keto-amino cytosine (Cyt) is τ = 730 ps or ∼ 700 times longer than that measured by femtosecond pump-probe ionization at higher vibrational excess energy, Eexc. N1-Alkylation increases the S1 lifetime up to τ = 1030 ps for N1-ethyl-Cyt but decreases it to 100 ps for N1-isopropyl-Cyt. Increasing the vibrational energy to Eexc = 300-550 cm(-1) decreases the lifetimes to 20-30 ps. The nonradiative dynamics of S1 cytosine is not solely a property of the amino-pyrimidinone chromophore but is strongly influenced by the N1-substituent. Correlated excited-state calculations predict that the gap between the S2((1)nOπ*) and S1((1)ππ*) states decreases along the series of N1-derivatives, thereby influencing the S1 state lifetime.
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Affiliation(s)
- Susan Blaser
- Department of Chemistry and Biochemistry, University of Bern , Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Maria A Trachsel
- Department of Chemistry and Biochemistry, University of Bern , Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Simon Lobsiger
- Department of Chemistry and Biochemistry, University of Bern , Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Timo Wiedmer
- Department of Chemistry and Biochemistry, University of Bern , Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Hans-Martin Frey
- Department of Chemistry and Biochemistry, University of Bern , Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Samuel Leutwyler
- Department of Chemistry and Biochemistry, University of Bern , Freiestrasse 3, CH-3012 Bern, Switzerland
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134
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Vayá I, Brazard J, Huix-Rotllant M, Thazhathveetil AK, Lewis FD, Gustavsson T, Burghardt I, Improta R, Markovitsi D. High-Energy Long-Lived Mixed Frenkel-Charge-Transfer Excitons: From Double Stranded (AT)n to Natural DNA. Chemistry 2016; 22:4904-14. [PMID: 26928984 DOI: 10.1002/chem.201504007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Indexed: 01/07/2023]
Abstract
The electronic excited states populated upon absorption of UV photons by DNA are extensively studied in relation to the UV-induced damage to the genetic code. Here, we report a new unexpected relaxation pathway in adenine-thymine double-stranded structures (AT)n . Fluorescence measurements on (AT)n hairpins (six and ten base pairs) and duplexes (20 and 2000 base pairs) reveal the existence of an emission band peaking at approximately 320 nm and decaying on the nanosecond time scale. Time-dependent (TD)-DFT calculations, performed for two base pairs and exploring various relaxation pathways, allow the assignment of this emission band to excited states resulting from mixing between Frenkel excitons and adenine-to-thymine charge-transfer states. Emission from such high-energy long-lived mixed (HELM) states is in agreement with their fluorescence anisotropy (0.03), which is lower than that expected for π-π* states (≥0.1). An increase in the size of the system quenches π-π* fluorescence while enhancing HELM fluorescence. The latter process varies linearly with the hypochromism of the absorption spectra, both depending on the coupling between π-π* and charge-transfer states. Subsequently, we identify the common features between the HELM states of (AT)n structures with those reported previously for alternating (GC)n : high emission energy, low fluorescence anisotropy, nanosecond lifetimes, and sensitivity to conformational disorder. These features are also detected for calf thymus DNA in which HELM states could evolve toward reactive π-π* states, giving rise to delayed fluorescence.
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Affiliation(s)
- Ignacio Vayá
- LIDYL, CEA, CNRS, Université Paris Saclay, 91191, Gif-sur-Yvette, France
| | - Johanna Brazard
- LIDYL, CEA, CNRS, Université Paris Saclay, 91191, Gif-sur-Yvette, France
| | - Miquel Huix-Rotllant
- LIDYL, CEA, CNRS, Université Paris Saclay, 91191, Gif-sur-Yvette, France.,Institut für Physikalische und Theoretische Chemie, Goethe-Universität, Max-von-Laue-Str. 7, 60438, Frankfurt am Main, Germany
| | | | - Frederick D Lewis
- Department of Chemistry, Northwestern University, Evanston, Illinois, 60208, USA.
| | - Thomas Gustavsson
- LIDYL, CEA, CNRS, Université Paris Saclay, 91191, Gif-sur-Yvette, France
| | - Irene Burghardt
- Institut für Physikalische und Theoretische Chemie, Goethe-Universität, Max-von-Laue-Str. 7, 60438, Frankfurt am Main, Germany
| | - Roberto Improta
- Istituto Biostrutture e Bioimmagini-Consiglio Nazionale delle Ricerche, Via mezzocannone 16, 80136, Napoli, Italy.
| | - Dimitra Markovitsi
- LIDYL, CEA, CNRS, Université Paris Saclay, 91191, Gif-sur-Yvette, France.
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135
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Improta R, Santoro F, Blancafort L. Quantum Mechanical Studies on the Photophysics and the Photochemistry of Nucleic Acids and Nucleobases. Chem Rev 2016; 116:3540-93. [PMID: 26928320 DOI: 10.1021/acs.chemrev.5b00444] [Citation(s) in RCA: 341] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The photophysics and photochemistry of DNA is of great importance due to the potential damage of the genetic code by UV light. Quantum mechanical studies have played a key role in interpretating the results of modern time-resolved pump-probe spectroscopy, and in elucidating the main photoactivated reactive paths. This review provides a concise, complete picture of the computational studies carried out, approximately, in the past decade. We start with an overview of the photophysics of the nucleobases in the gas phase and in solution. We discuss the proposed mechanisms for ultrafast decay to the ground state, that involve conical intersections, consider the role of triplet states, and analyze how the solvent modulates the photophysics. Then we move to larger systems, from dinucleotides to single- and double-stranded oligonucleotides. We focus on the possible role of charge transfer and delocalized or excitonic states in the photophysics of these systems and discuss the main photochemical paths. We finish with an outlook on the current challenges in the field and future directions of research.
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Affiliation(s)
- Roberto Improta
- Istituto di Biostrutture Biommagini (IBB-CNR), CNR-Consiglio Nazionale delle Ricerche , Via Mezzocannone 16, I-80134, Napoli, Italy
| | - Fabrizio Santoro
- Area della Ricerca di Pisa, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), CNR-Consiglio Nazionale delle Ricerche , Via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Lluís Blancafort
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi , 17071 Girona, Spain
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136
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Matthews E, Sen A, Yoshikawa N, Bergström E, Dessent CEH. UV laser photoactivation of hexachloroplatinate bound to individual nucleobases in vacuo as molecular level probes of a model photopharmaceutical. Phys Chem Chem Phys 2016; 18:15143-52. [DOI: 10.1039/c6cp01676f] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
UV excitation of mass-selected hexachloroplatinate–nucleobase clusters provides detailed insight into the photophysics and photochemistry of a model DNA photopharmaceutical.
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Affiliation(s)
| | - Ananya Sen
- Department of Chemistry
- University of York
- York
- UK
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137
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Martinez-Fernandez L, Zhang Y, de La Harpe K, Beckstead AA, Kohler B, Improta R. Photoinduced long-lived charge transfer excited states in AT-DNA strands. Phys Chem Chem Phys 2016; 18:21241-5. [DOI: 10.1039/c6cp04550b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The IR spectrum of a charge transfer (CT) excited electronic state in DNA has been computed for the first time, enabling assignment of the long-lived component of the transient IR spectrum of a d(AT)9 single strand to an A → T CT state.
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Affiliation(s)
| | - Yuyuan Zhang
- Department of Chemistry and Biochemistry
- Montana State University
- Bozeman
- USA
| | | | | | - Bern Kohler
- Department of Chemistry and Biochemistry
- Montana State University
- Bozeman
- USA
| | - Roberto Improta
- Istituto Biostrutture e Bioimmagini-Consiglio Nazionale delle Ricerche
- I-80134 Napoli
- Italy
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138
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Bucher DB, Kufner CL, Schlueter A, Carell T, Zinth W. UV-Induced Charge Transfer States in DNA Promote Sequence Selective Self-Repair. J Am Chem Soc 2015; 138:186-90. [PMID: 26651219 DOI: 10.1021/jacs.5b09753] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Absorption of UV-radiation in nucleotides initiates a number of photophysical and photochemical processes, which may finally cause DNA damage. One major decay channel of photoexcited DNA leads to reactive charge transfer states. This study shows that these states trigger self-repair of DNA photolesions. The experiments were performed by UV spectroscopy and HPLC on different single and double stranded oligonucleotides containing a cyclobutane pyrimidine dimer (CPD) lesion. In a first experiment we show that photoexcitation of adenine adjacent to a CPD has no influence on this lesion. However, excitation of a guanine (G) adenine (A) sequence leads to reformation of the intact thymine (T) bases. The involvement of two bases for the repair points to a long-living charge transfer state between G and A to be responsible for the repair. The negatively charged A radical anion donates an electron to the CPD, inducing ring splitting and repair. In contrast, a TA sequence, having an inverted charge distribution (T radical anion, A radical cation), is not able to repair the CPD lesion. The investigations show that the presence of an adjacent radical ion is not sufficient for repair. More likely it is the driving power represented by the oxidation potential of the radical ion, which controls the repair. Thus, repair capacities are strongly sequence-dependent, creating DNA regions with different tendencies of self-repair. This self-healing activity represents the simplest sequence-dependent DNA repair system.
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Affiliation(s)
- Dominik Benjamin Bucher
- BioMolecular Optics and Center for Integrated Protein Science, Ludwigs-Maximilians-Universität München , Oettingenstrasse 67, 80538 München, Germany.,Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München , Butenandtstrasse 5-13, 81377 München, Germany
| | - Corinna Lucia Kufner
- BioMolecular Optics and Center for Integrated Protein Science, Ludwigs-Maximilians-Universität München , Oettingenstrasse 67, 80538 München, Germany
| | - Alexander Schlueter
- BioMolecular Optics and Center for Integrated Protein Science, Ludwigs-Maximilians-Universität München , Oettingenstrasse 67, 80538 München, Germany
| | - Thomas Carell
- Center for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München , Butenandtstrasse 5-13, 81377 München, Germany
| | - Wolfgang Zinth
- BioMolecular Optics and Center for Integrated Protein Science, Ludwigs-Maximilians-Universität München , Oettingenstrasse 67, 80538 München, Germany
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139
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Markovitsi D. UV-induced DNA Damage: The Role of Electronic Excited States. Photochem Photobiol 2015; 92:45-51. [PMID: 26436855 DOI: 10.1111/php.12533] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/27/2015] [Indexed: 01/23/2023]
Abstract
The knowledge of the fundamental processes induced by the direct absorption of UV radiation by DNA allows extrapolating conclusions drawn from in vitro studies to the in-vivo DNA photoreactivity. In this respect, the characterization of the DNA electronic excited states plays a key role. For a long time, the mechanisms of DNA lesion formation were discussed in terms of generic "singlet" and "triplet" excited state reactivity. However, since the beginning of the 21(st) century, both experimental and theoretical studies revealed the existence of "collective" excited states, i.e. excited states delocalized over at least two bases. Two limiting cases are distinguished: Frenkel excitons (delocalized ππ* states) and charge-transfer states in which positive and negative charges are located on different bases. The importance of collective excited states in photon absorption (in particular in the UVA spectral domain), the redistribution of the excitation energy within DNA, and the formation of dimeric pyrimidine photoproducts is discussed. The dependence of the behavior of the collective excited states on conformational motions of the nucleic acids is highlighted.
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Affiliation(s)
- Dimitra Markovitsi
- CNRS, IRAMIS, LIDYL, Laboratoire Francis Perrin, URA 2453, F-91191 Gif-sur-Yvette, France
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140
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Bélanger F, Angers JP, Fortier É, Hammond-Martel I, Costantino S, Drobetsky E, Wurtele H. Mutations in Replicative Stress Response Pathways Are Associated with S Phase-specific Defects in Nucleotide Excision Repair. J Biol Chem 2015; 291:522-37. [PMID: 26578521 DOI: 10.1074/jbc.m115.685883] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Indexed: 01/02/2023] Open
Abstract
Nucleotide excision repair (NER) is a highly conserved pathway that removes helix-distorting DNA lesions induced by a plethora of mutagens, including UV light. Our laboratory previously demonstrated that human cells deficient in either ATM and Rad3-related (ATR) kinase or translesion DNA polymerase η (i.e. key proteins that promote the completion of DNA replication in response to UV-induced replicative stress) are characterized by profound inhibition of NER exclusively during S phase. Toward elucidating the mechanistic basis of this phenomenon, we developed a novel assay to quantify NER kinetics as a function of cell cycle in the model organism Saccharomyces cerevisiae. Using this assay, we demonstrate that in yeast, deficiency of the ATR homologue Mec1 or of any among several other proteins involved in the cellular response to replicative stress significantly abrogates NER uniquely during S phase. Moreover, initiation of DNA replication is required for manifestation of this defect, and S phase NER proficiency is correlated with the capacity of individual mutants to respond to replicative stress. Importantly, we demonstrate that partial depletion of Rfa1 recapitulates defective S phase-specific NER in wild type yeast; moreover, ectopic RPA1-3 overexpression rescues such deficiency in either ATR- or polymerase η-deficient human cells. Our results strongly suggest that reduction of NER capacity during periods of enhanced replicative stress, ostensibly caused by inordinate sequestration of RPA at stalled DNA replication forks, represents a conserved feature of the multifaceted eukaryotic DNA damage response.
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Affiliation(s)
- François Bélanger
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and
| | - Jean-Philippe Angers
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and the Programme de Biologie Moléculaire
| | - Émile Fortier
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and
| | - Ian Hammond-Martel
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and
| | - Santiago Costantino
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and Département d'ophtalmologie, and
| | - Elliot Drobetsky
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and Département de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Hugo Wurtele
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and Département de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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141
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Brister MM, Crespo-Hernández CE. Direct Observation of Triplet-State Population Dynamics in the RNA Uracil Derivative 1-Cyclohexyluracil. J Phys Chem Lett 2015; 6:4404-9. [PMID: 26538051 DOI: 10.1021/acs.jpclett.5b01901] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Investigation of the excited-state dynamics in nucleic acid monomers is an area of active research due to the crucial role these early events play in DNA and RNA photodamage. The dynamics and rate at which the triplet state is populated are key mechanistic pathways yet to be fully elucidated. Direct spectroscopic evidence is presented in this contribution for intersystem crossing dynamics in a uracil derivative, 1-cyclohexyluracil. It is shown that intersystem crossing to the triplet manifold occurs in one picosecond or less in acetonitrile solution-at least an order of magnitude faster than previously estimated experimentally. Broadband transient absorption measurements also reveal the primary electronic relaxation pathways of the uracil chromophore, including the absorption spectra of the (1)ππ*, (1)nπ*, and (3)ππ* states and the rates of vibrational cooling in the ground and (3)ππ* states. The experimental results are supported by density functional calculations.
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Affiliation(s)
- Matthew M Brister
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Carlos E Crespo-Hernández
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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142
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Röttger K, Marroux HJB, Grubb MP, Coulter PM, Böhnke H, Henderson AS, Galan MC, Temps F, Orr‐Ewing AJ, Roberts GM. Ultraviolet Absorption Induces Hydrogen‐Atom Transfer in G⋅C Watson–Crick DNA Base Pairs in Solution. Angew Chem Int Ed Engl 2015; 54:14719-22. [DOI: 10.1002/anie.201506940] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/07/2015] [Indexed: 02/05/2023]
Affiliation(s)
- Katharina Röttger
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
- Institut für Physikalische Chemie, Christian‐Albrechts‐Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel (Germany)
| | - Hugo J. B. Marroux
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Michael P. Grubb
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Philip M. Coulter
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Hendrik Böhnke
- Institut für Physikalische Chemie, Christian‐Albrechts‐Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel (Germany)
| | | | - M. Carmen Galan
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Friedrich Temps
- Institut für Physikalische Chemie, Christian‐Albrechts‐Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel (Germany)
| | - Andrew J. Orr‐Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Gareth M. Roberts
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
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143
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Röttger K, Marroux HJB, Grubb MP, Coulter PM, Böhnke H, Henderson AS, Galan MC, Temps F, Orr‐Ewing AJ, Roberts GM. Ultraviolet Absorption Induces Hydrogen‐Atom Transfer in G⋅C Watson–Crick DNA Base Pairs in Solution. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201506940] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Katharina Röttger
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
- Institut für Physikalische Chemie, Christian‐Albrechts‐Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel (Germany)
| | - Hugo J. B. Marroux
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Michael P. Grubb
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Philip M. Coulter
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Hendrik Böhnke
- Institut für Physikalische Chemie, Christian‐Albrechts‐Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel (Germany)
| | | | - M. Carmen Galan
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Friedrich Temps
- Institut für Physikalische Chemie, Christian‐Albrechts‐Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel (Germany)
| | - Andrew J. Orr‐Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
| | - Gareth M. Roberts
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK)
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144
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Bucher DB, Pilles BM, Carell T, Zinth W. Dewar Lesion Formation in Single- and Double-Stranded DNA is Quenched by Neighboring Bases. J Phys Chem B 2015; 119:8685-92. [DOI: 10.1021/acs.jpcb.5b04694] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Dominik B. Bucher
- BioMolecular
Optics and Center for Integrated Protein Science, Ludwig-Maximilians- Universität München Oettingenstrasse 67, 80538 München, Germany
- Center
for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
| | - Bert M. Pilles
- BioMolecular
Optics and Center for Integrated Protein Science, Ludwig-Maximilians- Universität München Oettingenstrasse 67, 80538 München, Germany
| | - Thomas Carell
- Center
for Integrated Protein Science at the Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
| | - Wolfgang Zinth
- BioMolecular
Optics and Center for Integrated Protein Science, Ludwig-Maximilians- Universität München Oettingenstrasse 67, 80538 München, Germany
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