1
|
Kufner CL, Crucilla S, Ding D, Stadlbauer P, Šponer J, Szostak JW, Sasselov DD, Szabla R. Photoinduced charge separation and DNA self-repair depend on sequence directionality and stacking pattern. Chem Sci 2024; 15:2158-2166. [PMID: 38332835 PMCID: PMC10848779 DOI: 10.1039/d3sc04971j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 12/27/2023] [Indexed: 02/10/2024] Open
Abstract
Charge separation is one of the most common consequences of the absorption of UV light by DNA. Recently, it has been shown that this process can enable efficient self-repair of cyclobutane pyrimidine dimers (CPDs) in specific short DNA oligomers such as the GAT[double bond, length as m-dash]T sequence. The mechanism was characterized as sequential electron transfer through the nucleobase stack which is controlled by the redox potentials of nucleobases and their sequence. Here, we demonstrate that the inverse sequence T[double bond, length as m-dash]TAG promotes self-repair with higher quantum yields (0.58 ± 0.23%) than GAT[double bond, length as m-dash]T (0.44 ± 0.18%) in a comparative study involving UV-irradiation experiments. After extended exposure to UV irradiation, a photostationary equilibrium between self-repair and damage formation is reached at 33 ± 13% for GAT[double bond, length as m-dash]T and at 40 ± 16% for T[double bond, length as m-dash]TAG, which corresponds to the maximum total yield of self-repair. Molecular dynamics and quantum mechanics/molecular mechanics (QM/MM) simulations allowed us to assign this disparity to better stacking overlap between the G and A bases, which lowers the energies of the key A-˙G+˙ charge transfer state in the dominant conformers of the T[double bond, length as m-dash]TAG tetramer. These conformational differences also hinder alternative photorelaxation pathways of the T[double bond, length as m-dash]TAG tetranucleotide, which otherwise compete with the sequential electron transfer mechanism responsible for CPD self-repair. Overall, we demonstrate that photoinduced electron transfer is strongly dependent on conformation and the availability of alternative photodeactivation mechanisms. This knowledge can be used in the identification and prediction of canonical and modified DNA sequences exhibiting efficient electron transfer. It also further contributes to our understanding of DNA self-repair and its potential role in the photochemical selection of the most photostable sequences on the early Earth.
Collapse
Affiliation(s)
- Corinna L Kufner
- Department of Astronomy, Harvard-Smithsonian Center for Astrophysics 60 Garden Street Cambridge MA 02138 USA
| | - Sarah Crucilla
- Department of Astronomy, Harvard-Smithsonian Center for Astrophysics 60 Garden Street Cambridge MA 02138 USA
- Department of Earth and Planetary Sciences, Harvard University Cambridge Massachusetts 02138 USA
| | - Dian Ding
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital Boston Massachusetts 02114 USA
- Department of Chemistry and Chemical Biology, Harvard University Cambridge Massachusetts 02138 USA
| | - Petr Stadlbauer
- Institute of Biophysics of the Czech Academy of Sciences Královopolská 135 61200 Brno Czech Republic
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacky University Olomouc Slechtitelu 241/27, 783 71, Olomouc - Holice Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences Královopolská 135 61200 Brno Czech Republic
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacky University Olomouc Slechtitelu 241/27, 783 71, Olomouc - Holice Czech Republic
| | - Jack W Szostak
- Howard Hughes Medical Institute, The University of Chicago Chicago IL 60637 USA
- Department of Chemistry, The University of Chicago Chicago Illinois 60637 USA
| | - Dimitar D Sasselov
- Department of Astronomy, Harvard-Smithsonian Center for Astrophysics 60 Garden Street Cambridge MA 02138 USA
| | - Rafał Szabla
- Institute of Advanced Materials, Faculty of Chemistry, Wrocław University of Science and Technology Wybrzeże Wyspiańskiego 27 Wrocław 50-370 Poland
| |
Collapse
|
2
|
Herbert JM. Visualizing and characterizing excited states from time-dependent density functional theory. Phys Chem Chem Phys 2024; 26:3755-3794. [PMID: 38226636 DOI: 10.1039/d3cp04226j] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Time-dependent density functional theory (TD-DFT) is the most widely-used electronic structure method for excited states, due to a favorable combination of low cost and semi-quantitative accuracy in many contexts, even if there are well recognized limitations. This Perspective describes various ways in which excited states from TD-DFT calculations can be visualized and analyzed, both qualitatively and quantitatively. This includes not just orbitals and densities but also well-defined statistical measures of electron-hole separation and of Frenkel-type exciton delocalization. Emphasis is placed on mathematical connections between methods that have often been discussed separately. Particular attention is paid to charge-transfer diagnostics, which provide indicators of when TD-DFT may not be trustworthy due to its categorical failure to describe long-range electron transfer. Measures of exciton size and charge separation that are directly connected to the underlying transition density are recommended over more ad hoc metrics for quantifying charge-transfer character.
Collapse
Affiliation(s)
- John M Herbert
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
| |
Collapse
|
3
|
Ling CCH, Chan WX, Siow JX, Loh ZH. Ultrafast Vibrational Wave Packet Dynamics of the Aqueous Guanine Radical Anion Induced by Photodetachment. J Phys Chem A 2024; 128:626-635. [PMID: 38207335 DOI: 10.1021/acs.jpca.3c08232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Studying the ultrafast dynamics of ionized aqueous biomolecules is important for gaining an understanding of the interaction of ionizing radiation with biological matter. Guanine plays an essential role in biological systems as one of the four nucleobases that form the building blocks of deoxyribonucleic acid (DNA). Guanine radicals can induce oxidative damage to DNA, particularly due to the lower ionization potential of guanine compared to the other nucleobases, sugars, and phosphate groups that are constituents of DNA. This study utilizes femtosecond optical pump-probe spectroscopy to observe the ultrafast vibrational wave packet dynamics of the guanine radical anion launched by photodetachment of the aqueous guanine dianion. The vibrational wave packet motion is resolved into 11 vibrational modes along which structural reorganization occurs upon photodetachment. These vibrational modes are assigned with the aid of density functional theory (DFT) calculations. Our work sheds light on the ultrafast vibrational dynamics following the ionization of nucleobases in an aqueous medium.
Collapse
Affiliation(s)
- Christine Chun Hui Ling
- School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Wei Xin Chan
- School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Jing Xuan Siow
- School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Zhi-Heng Loh
- School of Chemistry, Chemical Engineering and Biotechnology, and School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| |
Collapse
|
4
|
Lee W, Matsika S. Mechanistic Aspects of the Effect of Flanking Nucleotide Sequence on CPD Formation and CPD Self-Repair in DNA. J Phys Chem B 2023; 127:18-25. [PMID: 36574488 DOI: 10.1021/acs.jpcb.2c06680] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A cyclobutane pyrimidine dimer (CPD) is a photolesion which is produced by a cycloaddition reaction between two stacked pyrimidine bases upon UV light absorption. Because of its harmful effect on important cellular processes involving DNA and especially its relevance to skin cancer, the mechanisms of how a CPD is formed or repaired have been studied extensively, and it has been demonstrated that flanking nucleotide sequences play a crucial role in CPD formation or self-repair. Understanding the mechanisms behind this sequence dependence of CPD formation or self-repair is of great importance because it can give us valuable information on which sequence will be vulnerable to this DNA photodamage. This Perspective focuses on the mechanisms of how flanking nucleotide sequences affect CPD formation or self-repair, especially highlighting the role of computational studies in this field.
Collapse
Affiliation(s)
- Wook Lee
- Department of Biochemistry, Kangwon National University, Chuncheon 24341, Korea
| | - Spiridoula Matsika
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| |
Collapse
|
5
|
Hégely B, Szirmai Á, Mester D, Tajti A, Szalay PG, Kállay M. Performance of Multilevel Methods for Excited States. J Phys Chem A 2022; 126:6548-6557. [PMID: 36095318 PMCID: PMC9511572 DOI: 10.1021/acs.jpca.2c05013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/30/2022] [Indexed: 11/29/2022]
Abstract
The performance of multilevel quantum chemical approaches, which utilize an atom-based system partitioning scheme to model various electronic excited states, is studied. The considered techniques include the mechanical-embedding (ME) of "our own N-layered integrated molecular orbital and molecular mechanics" (ONIOM) method, the point charge embedding (PCE), the electronic-embedding (EE) of ONIOM, the frozen density-embedding (FDE), the projector-based embedding (PbE), and our local domain-based correlation method. For the investigated multilevel approaches, the second-order algebraic-diagrammatic construction [ADC(2)] approach was utilized as the high-level method, which was embedded in either Hartree-Fock or a density functional environment. The XH-27 test set of Zech et al. [ J. Chem. Theory Comput., 2018, 14, 4028] was used for the assessment, where organic dyes interact with several solvent molecules. With the selection of the chromophores as active subsystems, we conclude that the most reliable approach is local domain-based ADC(2) [L-ADC(2)], and the least robust schemes are ONIOM-ME and ONIOM-EE. The PbE, FDE, and PCE techniques often approach the accuracy of the L-ADC(2) scheme, but their precision is far behind. The results suggest that a more conservative subsystem selection algorithm or the inclusion of subsystem charge-transfers is required for the atom-based cost-efficient methods to produce high-accuracy excitation energies.
Collapse
Affiliation(s)
- Bence Hégely
- Department
of Physical Chemistry and Materials Science, Faculty of Chemical Technology
and Biotechnology, Budapest University of
Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- ELKH-BME
Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Ádám
B. Szirmai
- Laboratory
of Theoretical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, P.O. Box 32, H-1518 Budapest 112, Hungary
| | - Dávid Mester
- Department
of Physical Chemistry and Materials Science, Faculty of Chemical Technology
and Biotechnology, Budapest University of
Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- ELKH-BME
Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Attila Tajti
- Laboratory
of Theoretical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, P.O. Box 32, H-1518 Budapest 112, Hungary
| | - Péter G. Szalay
- Laboratory
of Theoretical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, P.O. Box 32, H-1518 Budapest 112, Hungary
| | - Mihály Kállay
- Department
of Physical Chemistry and Materials Science, Faculty of Chemical Technology
and Biotechnology, Budapest University of
Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- ELKH-BME
Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| |
Collapse
|
6
|
Martínez Fernández L, Santoro F, Improta R. Nucleic Acids as a Playground for the Computational Study of the Photophysics and Photochemistry of Multichromophore Assemblies. Acc Chem Res 2022; 55:2077-2087. [PMID: 35833758 DOI: 10.1021/acs.accounts.2c00256] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
ConspectusThe interaction between light and multichromophoric assemblies (MCAs) is the primary event of many fundamental processes, from photosynthesis to organic photovoltaics, and it triggers dynamical processes that share remarkable similarities at the molecular scale: light absorption, energy and charge transfer, internal conversions, emission, and so on. Those events often involve many chromophores and different excited electronic states that are coupled on an ultrafast time scale. This Account aims to discuss some of the chemical physical effects ruling these processes, a fundamental step toward their control, based on our experience on nucleic acids.In the last 15 years, we have, indeed, studied the photophysics and photochemistry of DNA and its components. By combining different quantum mechanical methods, we investigated the molecular processes responsible for the damage of the genetic code or, on the contrary, those preventing it by dissipating the excess energy deposited in the system by UV absorption. Independently of its fundamental biological role, DNA, with its fluctuating closely stacked bases stabilized by weak nonbonding interactions, can be considered a prototypical MCA. Therefore, it allows one to tackle within a single system many of the conceptual and methodological challenges involved in the study of photoinduced processes in MCA.In this Account, by using the outcome of our studies on oligonucleotides as a guideline, we thus highlight the most critical modellistic issues to be faced when studying, either experimentally or computationally, the interaction between UV light and DNA and, at the same time, bring out their general relevance for the study of MCAs.We first discuss the rich photoactivated dynamics of nucleobases (the chromophores), highlighting the main effects modulating the interplay between their excited states and how the latter can affect the photoactivated dynamics of the polynucleotides, either providing effective monomer-like nonradiative decay routes or triggering reactive processes (e.g., triplet generation).We then tackle the reaction paths involving multiple bases, showing that in the DNA duplex the most important ones involve two stacked bases, forming a neutral excimer or a charge transfer (CT) state, which exhibit different spectral signatures and photochemical reactivity. In particular, we analyze the factors affecting the dynamic equilibrium between the excimer and CT, such as the fluctuations of the backbone or the rearrangement of the solvent.Next, we highlight the importance of the effects not directly connected to the chromophores, such as the flexibility of the backbone or the solvent effect. The former, affecting the stacking geometry of the bases, can determine the preference between different deactivation paths. The latter is particularly influential for CT states, making very important an accurate treatment of dynamical solvation effects, involving both the solvent bulk and specific solute-solvent interactions.In the last section, we describe the main methodological challenges related to the study of polynucleotide excited states and stress the benefits derived by the integration of complementary approaches, both computational and experimental. Only exploiting different point of views, in our opinion, it is possible to shed light on the complex phenomena triggered by light absorption in DNA, as in every MCA.
Collapse
Affiliation(s)
- Lara Martínez Fernández
- Departamento de Química, Facultad de Ciencias and Institute for Advanced Research in Chemistry (IADCHEM), Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, 28049 Madrid, Spain
| | - Fabrizio Santoro
- Istituto di Chimica dei Composti Organometallici (ICCOM-CNR), Area della Ricerca del CNR, Via Moruzzi 1, I-56124 Pisa, Italy
| | - Roberto Improta
- Istituto di Biostrutture e Bioimmagini-CNR (IBB-CNR), Via De Amicis 95, I-80145 Napoli, Italy
| |
Collapse
|
7
|
Milovanović B, Novak J, Etinski M, Domcke W, Došlić N. On the propensity of formation of cyclobutane dimers in face-to-face and face-to-back uracil stacks in solution. Phys Chem Chem Phys 2022; 24:14836-14845. [PMID: 35697028 DOI: 10.1039/d2cp00495j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UV irradiation of RNA leads to the formation of intra- and inter-strand crosslinks of cyclobutane type. Despite the importance of this reaction, relatively little is known about how the mutual orientation of the two bases affects the outcome of the reaction. Here we report a comparative nonadiabatic molecular dynamics study of face-to-back (F2B) and face-to-face (F2F) stacked uracil-water clusters. The computations were performed using the second-order algebraic-diagrammatic-construction (ADC(2)) method. We found that F2B stacked uracil-water clusters either relax non-reactively to the ground state by an ethylenic twist around the CC bond or remain in the lowest nπ* state in which the two bases gradually move away from each other. This finding is consistent with the low propensity for the formation of intra-strand cyclobutane dimers between adjacent RNA bases. On the contrary, in F2F stacked uracil-water clusters, in addition to non-reactive deactivation, we found a pro-reactive deactivation pathway, which may lead to the formation of cyclobutane uracil dimers in the electronic ground state. On a qualitative level, the observed photodynamics of F2F stacked uracil-water clusters explains the greater propensity of RNA to form inter-strand cyclobutane-type crosslinks.
Collapse
Affiliation(s)
| | - Jurica Novak
- Department of Biotechnology, University of Rijeka, HR-51000 Rijeka, Croatia.,Scientific and Educational Center "Biomedical Technologies" School of Medical Biology, South Ural State University, RU-454080, Chelyabinsk, Russia.,Center for Artificial Intelligence and Cybersecurity, University of Rijeka, 51000 Rijeka, Croatia
| | - Mihajlo Etinski
- University of Belgrade, Faculty of Physical Chemistry, Belgrade, Serbia
| | - Wolfgang Domcke
- Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Nađa Došlić
- Department of Physical Chemistry, Ruđer Bošković Institute, Zagreb, Croatia.
| |
Collapse
|
8
|
Szabla R, Zdrowowicz M, Spisz P, Green NJ, Stadlbauer P, Kruse H, Šponer J, Rak J. 2,6-diaminopurine promotes repair of DNA lesions under prebiotic conditions. Nat Commun 2021; 12:3018. [PMID: 34021158 PMCID: PMC8139960 DOI: 10.1038/s41467-021-23300-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 04/20/2021] [Indexed: 01/04/2023] Open
Abstract
High-yielding and selective prebiotic syntheses of RNA and DNA nucleotides involve UV irradiation to promote the key reaction steps and eradicate biologically irrelevant isomers. While these syntheses were likely enabled by UV-rich prebiotic environment, UV-induced formation of photodamages in polymeric nucleic acids, such as cyclobutane pyrimidine dimers (CPDs), remains the key unresolved issue for the origins of RNA and DNA on Earth. Here, we demonstrate that substitution of adenine with 2,6-diaminopurine enables repair of CPDs with yields reaching 92%. This substantial self-repairing activity originates from excellent electron donating properties of 2,6-diaminopurine in nucleic acid strands. We also show that the deoxyribonucleosides of 2,6-diaminopurine and adenine can be formed under the same prebiotic conditions. Considering that 2,6-diaminopurine was previously shown to increase the rate of nonenzymatic RNA replication, this nucleobase could have played critical roles in the formation of functional and photostable RNA/DNA oligomers in UV-rich prebiotic environments. UV-induced photodamage that likely occurred during the prebiotic synthesis of DNA and RNA is still an untackled issue for their origin on early Earth. Here, the authors show that substitution of 2,6-diaminopurine for adenine enables repair of cyclobutane pyrimidine dimers with high yields, and demonstrate that both 2,6-diaminopurine and adenine nucleosides can be formed under the same prebiotic conditions.
Collapse
Affiliation(s)
- Rafał Szabla
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, UK. .,Institute of Physics, Polish Academy of Sciences, Warsaw, Poland.
| | | | - Paulina Spisz
- Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| | | | - Petr Stadlbauer
- Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Holger Kruse
- Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Janusz Rak
- Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| |
Collapse
|
9
|
Observation of Enhanced Dissociative Photochemistry in the Non-Native Nucleobase 2-Thiouracil. Molecules 2020; 25:molecules25143157. [PMID: 32664261 PMCID: PMC7397253 DOI: 10.3390/molecules25143157] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/30/2020] [Accepted: 07/08/2020] [Indexed: 12/12/2022] Open
Abstract
We present the first study to measure the dissociative photochemistry of 2-thiouracil (2-TU), an important nucleobase analogue with applications in molecular biology and pharmacology. Laser photodissociation spectroscopy is applied to the deprotonated and protonated forms of 2-TU, which are produced in the gas-phase using electrospray ionization mass spectrometry. Our results show that the deprotonated form of 2-thiouracil ([2-TU-H]−) decays predominantly by electron ejection and hence concomitant production of the [2-TU-H]· free-radical species, following photoexcitation across the UVA-UVC region. Thiocyanate (SCN−) and a m/z 93 fragment ion are also observed as photodecay products of [2-TU-H]− but at very low intensities. Photoexcitation of protonated 2-thiouracil ([2-TU·H]+) across the same UVA-UVC spectral region produces the m/z 96 cationic fragment as the major photofragment. This ion corresponds to ejection of an HS· radical from the precursor ion and is determined to be a product of direct excited state decay. Fragment ions associated with decay of the hot ground state (i.e., the ions we would expect to observe if 2-thiouracil was behaving like UV-dissipating uracil) are observed as much more minor products. This behaviour is consistent with enhanced intersystem crossing to triplet excited states compared to internal conversion back to the ground state. These are the first experiments to probe the effect of protonation/deprotonation on thionucleobase photochemistry, and hence explore the effect of pH at a molecular level on their photophysical properties.
Collapse
|
10
|
Rukin PS, Komarova KG, Fresch B, Collini E, Remacle F. Chirality of a rhodamine heterodimer linked to a DNA scaffold: an experimental and computational study. Phys Chem Chem Phys 2020; 22:7516-7523. [PMID: 32219241 DOI: 10.1039/d0cp00223b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The chiroptical properties of multi-chromophoric systems are governed by the intermolecular arrangement of the monomeric units. We report on a computational and experimental study of the linear optical properties and supramolecular structure of a rhodamine heterodimer assembled on a DNA scaffold. The experimental absorption and circular dichroism (CD) profiles confirm the dimer formation. Computationally, starting from low-cost DFT/TDDFT simulations of the bare dimer we attribute the measured -/+ CD sign sequence of the S1/S2 bands to a specific chiral conformation of the heterodimer. In the monomers, as typical for rhodamine dyes, the electric transition dipole of the lowest π-π* transition is parallel to the long axis of the xanthene planes. We show that in the heterodimer the sign sequence of the two CD bands is related to the orientation of these long axes. To account explicitly for environment effects, we use molecular dynamics (MD) simulations for characterizing the supramolecular structure of the two optical isomers tethered on DNA. Average absorption and CD-profiles were modeled using ab initio TDDFT calculations at the geometries sampled along a few nanosecond MD run. The absorption profiles computed for both optical isomers are in good agreement with the experimental absorption spectrum and do not allow one to discriminate between them. The computed averaged CD profiles provide the orientation of monomers in the enantiomer that is dominant under the experimental conditions.
Collapse
Affiliation(s)
- P S Rukin
- Theoretical Physical Chemistry, UR MolSys B6c, University of Liege, B4000, Liege, Belgium.
| | - K G Komarova
- Theoretical Physical Chemistry, UR MolSys B6c, University of Liege, B4000, Liege, Belgium.
| | - B Fresch
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
| | - E Collini
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
| | - F Remacle
- Theoretical Physical Chemistry, UR MolSys B6c, University of Liege, B4000, Liege, Belgium.
| |
Collapse
|
11
|
Wohlgemuth M, Mitrić R. Excitation energy transport in DNA modelled by multi-chromophoric field-induced surface hopping. Phys Chem Chem Phys 2020; 22:16536-16551. [DOI: 10.1039/d0cp02255a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Revealing the extended excited state lifetime due to excitation energy transport in DNA by multi-chromophoric field-induced surface-hopping (McFISH).
Collapse
Affiliation(s)
- Matthias Wohlgemuth
- Institut für Physikalische und Theoretische Chemie
- Julius-Maximilians-Universität Würzburg
- 97074 Würzburg
- Germany
| | - Roland Mitrić
- Institut für Physikalische und Theoretische Chemie
- Julius-Maximilians-Universität Würzburg
- 97074 Würzburg
- Germany
| |
Collapse
|
12
|
Böhnke H, Röttger K, Ingle RA, Marroux HJB, Bohnsack M, Schwalb NK, Orr-Ewing AJ, Temps F. Electronic Relaxation Dynamics of UV-Photoexcited 2-Aminopurine-Thymine Base Pairs in Watson-Crick and Hoogsteen Conformations. J Phys Chem B 2019; 123:2904-2914. [PMID: 30875228 DOI: 10.1021/acs.jpcb.9b02361] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The fluorescent analogue 2-aminopurine (2AP) of the canonical nucleobase adenine (6-aminopurine) base-pairs with thymine (T) without disrupting the helical structure of DNA. It therefore finds frequent use in molecular biology for probing DNA and RNA structures and conformational dynamics. However, detailed understanding of the processes responsible for fluorescence quenching remains largely elusive on a fundamental level. Although attempts have been made to ascribe decreased excited-state lifetimes to intrastrand charge-transfer and stacking interactions, possible influences from dynamic interstrand H-bonding have been widely ignored. Here, we investigate the electronic relaxation of UV-excited 2AP·T in Watson-Crick (WC) and Hoogsteen (HS) conformations. Although the WC conformation features slowed-down, monomer-like electronic relaxation in τ ∼ 1.6 ns toward ground-state recovery and triplet formation, the dynamics associated with 2AP·T in the HS motif exhibit faster deactivation in τ ∼ 70 ps. As recent research has revealed abundant transient interstrand H-bonding in the Hoogsteen motif for duplex DNA, the established model for dynamic fluorescence quenching may need to be revised in the light of our results. The underlying supramolecular photophysical mechanisms are discussed in terms of a proposed excited-state double-proton transfer as an efficient deactivation channel for recovery of the HS species in the electronic ground state.
Collapse
Affiliation(s)
- Hendrik Böhnke
- Institute of Physical Chemistry , Christian-Albrechts-University Kiel , Olshausenstr. 40 , 24098 Kiel , Germany
| | - Katharina Röttger
- Institute of Physical Chemistry , Christian-Albrechts-University Kiel , Olshausenstr. 40 , 24098 Kiel , Germany.,School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , U.K
| | - Rebecca A Ingle
- 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
| | - Mats Bohnsack
- Institute of Physical Chemistry , Christian-Albrechts-University Kiel , Olshausenstr. 40 , 24098 Kiel , Germany
| | - Nina K Schwalb
- Institute of Physical Chemistry , Christian-Albrechts-University Kiel , Olshausenstr. 40 , 24098 Kiel , Germany
| | - Andrew J Orr-Ewing
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , U.K
| | - Friedrich Temps
- Institute of Physical Chemistry , Christian-Albrechts-University Kiel , Olshausenstr. 40 , 24098 Kiel , Germany
| |
Collapse
|
13
|
Zou X, Sun Z, Zhao H, Zhang CY. Mechanistic insight into photocrosslinking reaction between triplet state 4-thiopyrimidine and thymine. Phys Chem Chem Phys 2019; 21:21305-21316. [DOI: 10.1039/c9cp04089g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multiple nonadiabatic pathways greatly facilitate the proceeding of photocrosslinking reactions between 4-thiopyrimidine and thymine.
Collapse
Affiliation(s)
- Xiaoran Zou
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Zhonghua Sun
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Hongmei Zhao
- Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Science
- Beijing
- P. R. China
| | - Chun-yang Zhang
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| |
Collapse
|
14
|
Daly S, Porrini M, Rosu F, Gabelica V. Electronic spectroscopy of isolated DNA polyanions. Faraday Discuss 2019; 217:361-382. [DOI: 10.1039/c8fd00207j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We address whether action spectroscopy could be used to investigate structural changes in gas-phase biomolecule (e.g. nucleic acid) ions, owing to changes in the environments of their chromophores, while taking advantage of the additional spectrometric separation of complex mixtures.
Collapse
Affiliation(s)
- Steven Daly
- Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle
- Université de Bordeaux
- Inserm & CNRS (ARNA, U1212, UMR5320)
- IECB
- 33607 Pessac
| | - Massimiliano Porrini
- Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle
- Université de Bordeaux
- Inserm & CNRS (ARNA, U1212, UMR5320)
- IECB
- 33607 Pessac
| | - Frédéric Rosu
- Institut Européen de Chimie et Biologie
- Université de Bordeaux
- CNRS & Inserm (IECB, UMS3033, US001)
- 33607 Pessac
- France
| | - Valérie Gabelica
- Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle
- Université de Bordeaux
- Inserm & CNRS (ARNA, U1212, UMR5320)
- IECB
- 33607 Pessac
| |
Collapse
|
15
|
Nogueira JJ, Roßbach S, Ochsenfeld C, González L. Effect of DNA Environment on Electronically Excited States of Methylene Blue Evaluated by a Three-Layered QM/QM/MM ONIOM Scheme. J Chem Theory Comput 2018; 14:4298-4308. [DOI: 10.1021/acs.jctc.8b00185] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Juan J. Nogueira
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 17, A-1090 Wien, Austria
| | - Sven Roßbach
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstrasse 7, D-81377 Munich, Germany
| | - Christian Ochsenfeld
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstrasse 7, D-81377 Munich, Germany
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 17, A-1090 Wien, Austria
| |
Collapse
|
16
|
Martínez-Fernández L, Improta R. Sequence dependence on DNA photochemistry: a computational study of photodimerization pathways in TpdC and dCpT dinucleotides. Photochem Photobiol Sci 2018; 17:586-591. [PMID: 29624198 DOI: 10.1039/c8pp00040a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The excited states involved in the main photodimerization paths in TpdC and dCpT are mapped by PCM/TD-M052X calculations, considering different dinucleotide conformers. As for TT steps, a cyclobutane pyrimidine dimer (CPD) is formed on the PES of the lowest energy exciton, delocalized over two stacked pyrimidines; 6-4 pyrimidine-pyrimidone (64-PP) adduct's formation involves instead a 5'-ter → 3'-ter charge transfer state. For dCpT, 64-PP dimerization occurs via a two-step reaction, which proceeds through an oxetane intermediate. For TpdC, instead, the final 64-PP product is obtained in a single step and it is as stable as the CPD photoproduct, explaining the relatively large yield of 64-PP found experimentally for TC steps in DNA.
Collapse
Affiliation(s)
- Lara Martínez-Fernández
- Consiglio Nationale delle Ricerche, Istituto di Biostrutture e Bioimmagini, 80134 Naples, Italy. and LIDYL, CEA, CNRS, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - Roberto Improta
- Consiglio Nationale delle Ricerche, Istituto di Biostrutture e Bioimmagini, 80134 Naples, Italy. and LIDYL, CEA, CNRS, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| |
Collapse
|
17
|
Lee W, Matsika S. Photochemical Formation of Cyclobutane Pyrimidine Dimers in DNA through Electron Transfer from a Flanking Base. Chemphyschem 2018; 19:1568-1571. [PMID: 29573315 DOI: 10.1002/cphc.201800151] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Indexed: 11/09/2022]
Abstract
Electron transfer (ET) to a pyrimidine base from external moieties is a common step involved in the quenching or repair of the cyclobutane pyrimidine dimer (CPD). In contrast, we present a pathway that is initiated by an ET from a flanking guanine base to a pyrimidine base, leading to the formation of a CPD. We studied a T5mCG sequence with a methylated cytosine and our results demonstrate that the pathway involves the formation of an exciplex and intersystem crossings. This pathway also provides an explanation for why the mutational hot spots are correlated with the methylated CpG sequences, which has been a significant issue in cancer research.
Collapse
Affiliation(s)
- Wook Lee
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania, 19122, United States.,Department of Chemistry, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Spiridoula Matsika
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania, 19122, United States
| |
Collapse
|
18
|
Brown KE, Singh APN, Wu YL, Ma L, Mishra AK, Phelan BT, Young RM, Lewis FD, Wasielewski MR. Fluorescent excimers and exciplexes of the purine base derivative 8-phenylethynyl-guanine in DNA hairpins. Faraday Discuss 2018; 207:217-232. [PMID: 29362748 DOI: 10.1039/c7fd00186j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ground- and excited-state electronic interactions between the nucleobase analog 8-(4'-phenylethynyl)deoxyguanosine, EG, with natural nucleobases and 7-deazaguanine, as well as between adjacent EG base analogs, have been characterized using a combination of steady-state spectroscopy and time-resolved fluorescence, absorption, and stimulated Raman spectroscopies. The properties of the nucleoside EG-H2 are only weakly perturbed upon incorporation into synthetic DNA hairpins in which thymine, cytosine or adenine are the bases flanking EG. Incorporation of the nucleoside to be adjacent to guanine or deazaguanine results in the formation of short-lived (40-80 ps) exciplexes, the charge transfer character of which increases as the oxidation potential of the donor decreases. Hairpins possessing two or three adjacent EG base analogs display exciton-coupled circular dichroism in the ground state and form long-lived fluorescent excited states upon electronic excitation. Incorporation of EG into the helical scaffold of the DNA hairpins places it adjacent to its neighboring nucleobases or a second EG, thus providing the close proximity required for the formation of exciplex or excimer intermediates upon geometric relaxation of the short-lived EG excited state. The three time-resolved spectroscopic methods employed permit both the characterization of the several intermediates and the kinetics of their formation and decay.
Collapse
Affiliation(s)
- Kristen E Brown
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Szabla R, Kruse H, Stadlbauer P, Šponer J, Sobolewski AL. Sequential electron transfer governs the UV-induced self-repair of DNA photolesions. Chem Sci 2018; 9:3131-3140. [PMID: 29732095 PMCID: PMC5916108 DOI: 10.1039/c8sc00024g] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 02/22/2018] [Indexed: 01/09/2023] Open
Abstract
Cyclobutane pyrimidine dimers (CpDs) are among the most common DNA lesions occurring due to the interaction with ultraviolet light. While photolyases have been well known as external factors repairing CpDs, the intrinsic self-repairing capabilities of the GAT 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 T DNA sequence were discovered only recently and are still largely obscure. Here, we elucidate the mechanistic details of this self-repair process by means of MD simulations and QM/MM computations involving the algebraic diagrammatic construction to the second order [ADC(2)] method. We show that local UV-excitation of guanine may be followed by up to three subsequent electron transfers, which may eventually enable efficient CpD ring opening when the negative charge resides on the T 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 T dimer. Consequently, the molecular mechanism of GAT 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 T self-repair can be envisaged as sequential electron transfer (SET) occurring downhill along the slope of the S1 potential energy surface. Even though the general features of the SET mechanism are retained in both of the studied stacked conformers, our optimizations of different S1/S0 state crossings revealed minor differences which could influence their self-repair efficiencies. We expect that such assessment of the availability and efficiency of the SET process in other DNA oligomers could hint towards other sequences exhibiting similar photochemical properties. Such explorations will be particularly fascinating in the context of the origins of biomolecules on Earth, owing to the lack of external repairing factors in the Archean age.
Collapse
Affiliation(s)
- Rafał Szabla
- Institute of Physics , Polish Academy of Sciences , Al. Lotników 32/46 , PL-02668 Warsaw , Poland.,Institute of Biophysics of the Czech Academy of Sciences , Královopolská 135 , 61265 Brno , Czech Republic .
| | - Holger Kruse
- Institute of Biophysics of the Czech Academy of Sciences , Královopolská 135 , 61265 Brno , Czech Republic .
| | - Petr Stadlbauer
- Institute of Biophysics of the Czech Academy of Sciences , Královopolská 135 , 61265 Brno , Czech Republic . .,Regional Centre of Advanced Technologies and Materials , Department of Physical Chemistry , Faculty of Science , Palacký University , 17. Listopadu 1192/12 , 77146 Olomouc , Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences , Královopolská 135 , 61265 Brno , Czech Republic .
| | - Andrzej L Sobolewski
- Institute of Physics , Polish Academy of Sciences , Al. Lotników 32/46 , PL-02668 Warsaw , Poland
| |
Collapse
|
20
|
Nguyen QL, Spata VA, Matsika S. Photophysical properties of pyrrolocytosine, a cytosine fluorescent base analogue. Phys Chem Chem Phys 2018; 18:20189-98. [PMID: 27251599 DOI: 10.1039/c6cp01559j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The photophysical behavior of pyrrolocytosine (PC), a fluorescent base analogue of cytosine, has been investigated using theoretical approaches. The similarities between the PC and cytosine structures allow PC to maintain the pseudo-Watson-Crick base-pairing arrangement with guanine. Cytosine, similar to the other natural nucleobases, is practically non-fluorescent, because of ultrafast radiationless decay occurring through conical intersections. PC displays a much higher fluorescence quantum yield than cytosine, making it an effective fluorescent marker to study the structure, function, and dynamics of DNA/RNA complexes. Similar to 2-aminopurine, a constitutional isomer of adenine that base-pairs with thymine, PC's fluorescence is quenched when it is incorporated into a dinucleotide or a trinucleotide. In this work we examine the photophysical properties of isolated PC, microhydrated PC, as well as, complexes where PC is either base-stacked or hydrogen-bonded with guanine. Our results indicate that hydration affects the radiationless decay pathways in PC by destabilizing conical intersections. The calculations of dimers and trimers show that the radiative decay is affected by π stacking, while the presence of charge transfer states between PC and guanine may contribute to radiationless decay.
Collapse
|
21
|
Madsen MM, Jones NC, Nielsen SB, Hoffmann SV. On the wavelength dependence of UV induced thymine photolesions: a synchrotron radiation circular dichroism study. Phys Chem Chem Phys 2018; 18:30436-30443. [PMID: 27781221 DOI: 10.1039/c6cp05980e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Solar mutagenesis via the formation of thymine dimer photoproducts is a primary cause of skin cancer. The aim of this study is to provide a direct method for following the development of photolesions in thymine single strands and to determine how the formation of these photoproducts depends on the excitation wavelength in the ultraviolet (UV) between 210 nm and 325 nm. Experiments were performed both with a 20 Hz pulsed, intense, tunable laser as well as UV lamps (at 254 nm and 302 nm), but we find that only the dose matters at these wavelengths for the yield of photoproducts. Hence in both cases the lesion process is due to one-photon absorption. The formation and yields of the photoproducts as the irradiation dose is increased is followed through measurement of synchrotron radiation circular dichroism (SRCD) spectra. A principal component analysis (PCA) of the SRCD data yields CD signatures for each of the resulting photoproducts and reveals a strong irradiation wavelength dependence upon which products are formed; cyclobutane pyrimidine dimers (CPDs) are formed primarily at higher irradiation wavelengths (from 250 to 300 nm); the 6,4 pyrimidine-pyrimidone photoadduct (64PP) is formed in the range 210 to 285 nm, with a higher rate of formation in the lower part of that range, while in the very lowest irradiation wavelength range (210 to 240 nm) we find thymidine monophosphate (dTMP), which indicates cleavage of the DNA backbone. Our work demonstrates the strength of SRCD spectroscopy compared to ordinary absorption spectroscopy, as the latter is not sufficient to obtain fingerprints of the thymine photoproducts.
Collapse
Affiliation(s)
- Marlene Møller Madsen
- Department of Physics & Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark. and Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Nykola C Jones
- Department of Physics & Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
| | - Steen Brøndsted Nielsen
- Department of Physics & Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
| | - Søren Vrønning Hoffmann
- Department of Physics & Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
| |
Collapse
|
22
|
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.
Collapse
Affiliation(s)
| | - Roberto Improta
- Consiglio Nazionale delle Ricerche
- Istituto di Biostrutture e Bioimmagini
- 80136 Naples
- Italy
- LIDYL
| |
Collapse
|
23
|
Rauer C, Nogueira JJ, Marquetand P, González L. Stepwise photosensitized thymine dimerization mediated by an exciton intermediate. MONATSHEFTE FUR CHEMIE 2017; 149:1-9. [PMID: 29290634 PMCID: PMC5738462 DOI: 10.1007/s00706-017-2108-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 11/20/2017] [Indexed: 11/26/2022]
Abstract
ABSTRACT Cyclobutane thymine dimerization is the most prominent DNA photoinduced damage. While the ultrafast mechanism that proceeds in the singlet manifold is nowadays well established, the triplet-state pathway is not completely understood. Here we report the underlying mechanism of the photosensitized dimerization process in the triplet state. Quantum chemical calculations, combined with wavefunction analysis, and nonadiabatic molecular dynamics simulations demonstrate that this is a stepwise reaction, traversing a long-lived triplet biradical intermediate, which is characterized as a Frenkel exciton with very small charge-transfer character. The low yield of the reaction is regulated by two factors: (i) a relatively large energy barrier that needs to be overcome to form the exciton intermediate, and (ii) a bifurcation of the ground-state potential-energy surface that mostly leads back to the Franck-Condon region because dimerization requires a very restricted combination of coordinates and velocities at the event of non-radiative decay to the ground state. GRAPHICAL ABSTRACT
Collapse
Affiliation(s)
- Clemens Rauer
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Juan J. Nogueira
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Philipp Marquetand
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| |
Collapse
|
24
|
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.
Collapse
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
| |
Collapse
|
25
|
Tzeli D, Mercouris T, Theodorakopoulos G, Petsalakis ID. Time-evolution study of photoinduced charge-transfer in tertiary amine-fluorophore systems. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.06.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
26
|
Nogueira JJ, Plasser F, González L. Electronic delocalization, charge transfer and hypochromism in the UV absorption spectrum of polyadenine unravelled by multiscale computations and quantitative wavefunction analysis. Chem Sci 2017; 8:5682-5691. [PMID: 28989607 PMCID: PMC5621053 DOI: 10.1039/c7sc01600j] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/09/2017] [Indexed: 12/23/2022] Open
Abstract
The characterization of the electronically excited states of DNA strands populated upon solar UV light absorption is essential to unveil light-induced DNA damage and repair processes. We report a comprehensive analysis of the electronic properties of the UV spectrum of single-stranded polyadenine based on theoretical calculations that include excitations over eight nucleobases of the DNA strand and environmental effects by a multiscale quantum mechanics/molecular mechanics scheme, conformational sampling by molecular dynamics, and a meaningful interpretation of the electronic structure by quantitative wavefunction analysis. We show that electronic excitations are extended mainly over two nucleobases with additional important contributions of monomer-like excitations and excitons delocalized over three monomers. Half of the spectral intensity derives from locally excited and Frenkel exciton states, while states with partial charge-transfer character account for the other half and pure charge-transfer states represent only a minor contribution. The hypochromism observed when going from the isolated monomer to the strand occurs independently from delocalization and charge transfer and is instead explained by long-range environmental perturbations of the monomer states.
Collapse
Affiliation(s)
- Juan J Nogueira
- Institute of Theoretical Chemistry , Faculty of Chemistry , University of Vienna , Währinger Straße 17 , 1090 Vienna , Austria . ; ;
| | - Felix Plasser
- Institute of Theoretical Chemistry , Faculty of Chemistry , University of Vienna , Währinger Straße 17 , 1090 Vienna , Austria . ; ;
| | - Leticia González
- Institute of Theoretical Chemistry , Faculty of Chemistry , University of Vienna , Währinger Straße 17 , 1090 Vienna , Austria . ; ;
| |
Collapse
|
27
|
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.
Collapse
Affiliation(s)
| | - Akos Banyasz
- LIDYL, CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | | | | |
Collapse
|
28
|
Iyer ESS, Sadybekov A, Lioubashevski O, Krylov AI, Ruhman S. Rewriting the Story of Excimer Formation in Liquid Benzene. J Phys Chem A 2017; 121:1962-1975. [DOI: 10.1021/acs.jpca.7b01070] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- E. Siva Subramaniam Iyer
- Institute
of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Arman Sadybekov
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Oleg Lioubashevski
- Institute
of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Anna I. Krylov
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Sanford Ruhman
- Institute
of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| |
Collapse
|
29
|
Marquetand P, Nogueira JJ, Mai S, Plasser F, González L. Challenges in Simulating Light-Induced Processes in DNA. Molecules 2016. [PMCID: PMC6155660 DOI: 10.3390/molecules22010049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In this contribution, we give a perspective on the main challenges in performing theoretical simulations of photoinduced phenomena within DNA and its molecular building blocks. We distinguish the different tasks that should be involved in the simulation of a complete DNA strand subject to UV irradiation: (i) stationary quantum chemical computations; (ii) the explicit description of the initial excitation of DNA with light; (iii) modeling the nonadiabatic excited state dynamics; (iv) simulation of the detected experimental observable; and (v) the subsequent analysis of the respective results. We succinctly describe the methods that are currently employed in each of these steps. While for each of them, there are different approaches with different degrees of accuracy, no feasible method exists to tackle all problems at once. Depending on the technique or combination of several ones, it can be problematic to describe the stacking of nucleobases, bond breaking and formation, quantum interferences and tunneling or even simply to characterize the involved wavefunctions. It is therefore argued that more method development and/or the combination of different techniques are urgently required. It is essential also to exercise these new developments in further studies on DNA and subsystems thereof, ideally comprising simulations of all of the different components that occur in the corresponding experiments.
Collapse
|
30
|
Rauer C, Nogueira JJ, Marquetand P, González L. Cyclobutane Thymine Photodimerization Mechanism Revealed by Nonadiabatic Molecular Dynamics. J Am Chem Soc 2016; 138:15911-15916. [PMID: 27682199 DOI: 10.1021/jacs.6b06701] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The formation of cyclobutane thymine dimers is one of the most important DNA carcinogenic photolesions induced by ultraviolet irradiation. The long debated question whether thymine dimerization after direct light excitation involves singlet or triplet states is investigated here for the first time using nonadiabatic molecular dynamics simulations. We find that the precursor of this [2 + 2] cycloaddition reaction is the singlet doubly π2π*2 excited state, which is spectroscopically rather dark. Excitation to the bright 1ππ* or dark 1nπ* excited states does not lead to thymine dimer formation. In all cases, intersystem crossing to the triplet states is not observed during the simulated time, indicating that ultrafast dimerization occurs in the singlet manifold. The dynamics simulations also show that dimerization takes place only when conformational control happens in the doubly excited state.
Collapse
Affiliation(s)
- Clemens Rauer
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna , Währinger Straße 17, 1090 Vienna, Austria
| | - Juan J Nogueira
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna , Währinger Straße 17, 1090 Vienna, Austria
| | - Philipp Marquetand
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna , Währinger Straße 17, 1090 Vienna, Austria
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna , Währinger Straße 17, 1090 Vienna, Austria
| |
Collapse
|
31
|
Kochman MA, Pola M, Miller RJD. Theoretical Study of the Photophysics of 8-Vinylguanine, an Isomorphic Fluorescent Analogue of Guanine. J Phys Chem A 2016; 120:6200-15. [DOI: 10.1021/acs.jpca.6b04723] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Michał A. Kochman
- Max Planck Institute for the Structure and Dynamics of Matter and Hamburg Centre for Ultrafast Imaging, Bldg. 99 (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Martina Pola
- Max Planck Institute for the Structure and Dynamics of Matter and Hamburg Centre for Ultrafast Imaging, Bldg. 99 (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
- Institut
für Theoretische Physik, Universität Hamburg, Jungiusstraße
9, 20355 Hamburg, Germany
| | - R. J. Dwayne Miller
- Max Planck Institute for the Structure and Dynamics of Matter and Hamburg Centre for Ultrafast Imaging, Bldg. 99 (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
- Department
of Chemistry and Physics, University of Toronto, 80 St. George
Street, Toronto, Ontario M5S 3H6, Canada
| |
Collapse
|
32
|
Szabla R, Góra RW, Janicki M, Šponer J. Photorelaxation of imidazole and adenine via electron-driven proton transfer along H2O wires. Faraday Discuss 2016; 195:237-251. [DOI: 10.1039/c6fd00131a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photochemically created πσ* states were classified among the most prominent factors determining the ultrafast radiationless deactivation and photostability of many biomolecular building blocks. In the past two decades, the gas phase photochemistry of πσ* excitations was extensively investigated and was attributed to N–H and O–H bond fission processes. However, complete understanding of the complex photorelaxation pathways of πσ* states in the aqueous environment was very challenging, owing to the direct participation of solvent molecules in the excited-state deactivation. Here, we present non-adiabatic molecular dynamics simulations and potential energy surface calculations of the photoexcited imidazole–(H2O)5 cluster using the algebraic diagrammatic construction method to the second-order [ADC(2)]. We show that electron driven proton transfer (EDPT) along a wire of at least two water molecules may lead to the formation of a πσ*/S0 state crossing, similarly to what we suggested for 2-aminooxazole. We expand on our previous findings by direct comparison of the imidazole–(H2O)5 cluster to non-adiabatic molecular dynamics simulations of imidazole in the gas phase, which reveal that the presence of water molecules extends the overall excited-state lifetime of the chromophore. To embed the results in a biological context, we provide calculations of potential energy surface cuts for the analogous photorelaxation mechanism present in adenine, which contains an imidazole ring in its structure.
Collapse
Affiliation(s)
- Rafał Szabla
- Institute of Biophysics
- Academy of Sciences of the Czech Republic
- Brno
- Czech Republic
| | - Robert W. Góra
- Department of Physical and Quantum Chemistry
- Faculty of Chemistry
- Wrocław University of Technology
- 50-370 Wrocław
- Poland
| | - Mikołaj Janicki
- Department of Physical and Quantum Chemistry
- Faculty of Chemistry
- Wrocław University of Technology
- 50-370 Wrocław
- Poland
| | - Jiří Šponer
- Institute of Biophysics
- Academy of Sciences of the Czech Republic
- Brno
- Czech Republic
- CEITEC–Central European Institute of Technology
| |
Collapse
|
33
|
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.
Collapse
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
| |
Collapse
|