1
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Brundridge NM, Fritz JM, Dickerhoff J, Yang D, McLuckey SA. Negative Electron Transfer Collision-Induced Dissociation of G-Quadruplexes: Uncovering the Guanine Radical Anion Loss Pathway. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:756-766. [PMID: 38456425 PMCID: PMC11022967 DOI: 10.1021/jasms.3c00443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
G-quadruplex (G4) DNA can form highly stable secondary structures in the presence of metal cations, and research has shown its potential as a transcriptional regulator for oncogenes in the human genome. In order to explore the interactions of DNA with metal cations using mass spectrometry, employing complementary fragmentation methods can enhance structural information. This study explores the use of ion-ion reactions for sequential negative electron transfer collision-induced dissociation (nET-CID) as a complement to traditional ion-trap CID (IT-CID). The resulting nET-CID data for G4 anions with and without metal cations show an increase in fragment ion type diversity and yield of structurally informative ions relative to IT-CID. The nET-CID yields greater sequence coverage by virtue of fragmentation at the 3'-side of thymine residues, which is lacking with IT-CID. Potassium adductions to backbone fragments in IT-CID and nET-CID spectra were nearly identical. Of note is a prominent fragment resulting from a loss of a 149 Da anion seen in nET-CID of large, G-rich sequences, proposed to be radical anion guanine loss. Neutral loss of neutral guanine (151 Da) and deprotonated nucleobase loss (150 Da) have been previously reported, but this is the first report of radical anion guanine loss (149 Da). Confirmation of the identity of the 149 Da anion results from the examination of the homonucleobase sequence 5'-GGGGGGGG-3'. Loss of a charged adenine radical anion at much lower relative abundance was also noted for the sequence 5'-AAAAAAAA-3'. DFT modeling indicates that the loss of a nucleobase as a radical anion from odd-electron nucleic acid anions is a thermodynamically favorable fragmentation pathway for G.
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Affiliation(s)
- Nicole M Brundridge
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Jordan M Fritz
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Jonathan Dickerhoff
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue Center for Cancer Research, Purdue University, 575 W. Stadium Avenue, West Lafayette, Indiana 47904, United States
| | - Danzhou Yang
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue Center for Cancer Research, Purdue University, 575 W. Stadium Avenue, West Lafayette, Indiana 47904, United States
| | - Scott A McLuckey
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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2
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Hannauer F, Black R, Ray AD, Stulz E, Langley GJ, Holman SW. Review of fragmentation of synthetic single-stranded oligonucleotides by tandem mass spectrometry from 2014 to 2022. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9596. [PMID: 37580500 PMCID: PMC10909466 DOI: 10.1002/rcm.9596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 08/16/2023]
Abstract
The fragmentation of oligonucleotides by mass spectrometry allows for the determination of their sequences. It is necessary to understand how oligonucleotides dissociate in the gas phase, which allows interpretation of data to obtain sequence information. Since 2014, a range of fragmentation mechanisms, including a novel internal rearrangement, have been proposed using different ion dissociation techniques. The recent publications have focused on the fragmentation of modified oligonucleotides such as locked nucleic acids, modified nucleobases (methylated, spacer, nebularine and aminopurine) and modification to the carbon 2'-position on the sugar ring; these modified oligonucleotides are of great interest as therapeutics. Comparisons of different dissociation techniques have been reported, including novel approaches such as plasma electron detachment dissociation and radical transfer dissociation. This review covers the period 2014-2022 and details the new knowledge gained with respect to oligonucleotide dissociation using tandem mass spectrometry (without priori sample digestion) during that time, with a specific focus on synthetic single-stranded oligonucleotides.
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Affiliation(s)
- Fabien Hannauer
- Chemistry, Faculty of Engineering and Physical SciencesUniversity of SouthamptonSouthamptonUK
| | - Rachelle Black
- New Modalities & Parenteral Development, Pharmaceutical Technology & Development, OperationsAstraZenecaMacclesfieldUK
| | - Andrew D. Ray
- New Modalities & Parenteral Development, Pharmaceutical Technology & Development, OperationsAstraZenecaMacclesfieldUK
| | - Eugen Stulz
- Chemistry, Faculty of Engineering and Physical SciencesUniversity of SouthamptonSouthamptonUK
| | - G. John Langley
- Chemistry, Faculty of Engineering and Physical SciencesUniversity of SouthamptonSouthamptonUK
| | - Stephen W. Holman
- Chemical Development, Pharmaceutical Technology & Development, OperationsAstraZenecaMacclesfieldUK
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3
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Liu M, O'Reilly D, Schwob L, Wang X, Zamudio-Bayer V, Lau JT, Bari S, Schlathölter T, Poully JC. Direct Observation of Charge, Energy, and Hydrogen Transfer between the Backbone and Nucleobases in Isolated DNA Oligonucleotides. Chemistry 2023; 29:e202203481. [PMID: 36478608 DOI: 10.1002/chem.202203481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022]
Abstract
Understanding how charge and energy, as well as protons and hydrogen atoms, are transferred in molecular systems as a result of an electronic excitation is fundamental for understanding the interaction between ionizing radiation and biological matter on the molecular level. To localize the excitation at the atomic scale, it was chosen to target phosphorus atoms in the backbone of gas-phase oligonucleotide anions and cations, by means of resonant photoabsorption at the L- and K-edges. The ionic photoproducts of the excitation process were studied by a combination of mass spectrometry and X-ray spectroscopy. The combination of absorption site selectivity and photoproduct sensitivity allowed the identification of X-ray spectral signatures of specific processes. Moreover, charge and/or energy as well as H transfer from the backbone to nucleobases has been directly observed. Although the probability of one versus two H transfer following valence ionization depends on the nucleobase, ionization of sugar or phosphate groups at the carbon K-edge or the phosphorus L-edge mainly leads to single H transfer to protonated adenine. Moreover, our results indicate a surprising proton-transfer process to specifically form protonated guanine after excitation or ionization of P 2p electrons.
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Affiliation(s)
- Min Liu
- CIMAP UMR 6252, CEA/, CNRS/, ENSICAEN/, Université de Caen Normandie, Bd Becquerel, 14070, Caen, France
| | - David O'Reilly
- CIMAP UMR 6252, CEA/, CNRS/, ENSICAEN/, Université de Caen Normandie, Bd Becquerel, 14070, Caen, France
| | | | - Xin Wang
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | | | - J Tobias Lau
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.,Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Sadia Bari
- Deutsches Elektronen-Synchrotron DESY, Germany
| | - Thomas Schlathölter
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands.,University College Groningen, University of Groningen, Groningen, The Netherlands
| | - Jean-Christophe Poully
- CIMAP UMR 6252, CEA/, CNRS/, ENSICAEN/, Université de Caen Normandie, Bd Becquerel, 14070, Caen, France
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4
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Tureček F. UV-vis spectroscopy of gas-phase ions. MASS SPECTROMETRY REVIEWS 2023; 42:206-226. [PMID: 34392556 DOI: 10.1002/mas.21726] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
Photodissociation action spectroscopy has made a great progress in expanding investigations of gas-phase ion structures. This review deals with aspects of gas-phase ion electronic excitations that result in wavelength-dependent dissociation and light emission via fluorescence, chiefly covering the ultraviolet and visible regions of the spectrum. The principles are briefly outlined and a few examples of instrumentation are presented. The main thrust of the review is to collect and selectively present applications of UV-vis action spectroscopy to studies of stable gas-phase ion structures and combinations of spectroscopy with ion mobility, collision-induced dissociation, and ion-ion reactions leading to the generation of reactive intermediates and electronic energy transfer.
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Affiliation(s)
- František Tureček
- Department of Chemistry, University of Washington, Seattle, Washington, USA
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5
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Grabarics M, Lettow M, Kirschbaum C, Greis K, Manz C, Pagel K. Mass Spectrometry-Based Techniques to Elucidate the Sugar Code. Chem Rev 2022; 122:7840-7908. [PMID: 34491038 PMCID: PMC9052437 DOI: 10.1021/acs.chemrev.1c00380] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Indexed: 12/22/2022]
Abstract
Cells encode information in the sequence of biopolymers, such as nucleic acids, proteins, and glycans. Although glycans are essential to all living organisms, surprisingly little is known about the "sugar code" and the biological roles of these molecules. The reason glycobiology lags behind its counterparts dealing with nucleic acids and proteins lies in the complexity of carbohydrate structures, which renders their analysis extremely challenging. Building blocks that may differ only in the configuration of a single stereocenter, combined with the vast possibilities to connect monosaccharide units, lead to an immense variety of isomers, which poses a formidable challenge to conventional mass spectrometry. In recent years, however, a combination of innovative ion activation methods, commercialization of ion mobility-mass spectrometry, progress in gas-phase ion spectroscopy, and advances in computational chemistry have led to a revolution in mass spectrometry-based glycan analysis. The present review focuses on the above techniques that expanded the traditional glycomics toolkit and provided spectacular insight into the structure of these fascinating biomolecules. To emphasize the specific challenges associated with them, major classes of mammalian glycans are discussed in separate sections. By doing so, we aim to put the spotlight on the most important element of glycobiology: the glycans themselves.
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Affiliation(s)
- Márkó Grabarics
- Institute
of Chemistry and Biochemistry, Freie Universität
Berlin, Arnimallee 22, 14195 Berlin, Germany
- Department
of Molecular Physics, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4−6, 14195 Berlin, Germany
| | - Maike Lettow
- Institute
of Chemistry and Biochemistry, Freie Universität
Berlin, Arnimallee 22, 14195 Berlin, Germany
- Department
of Molecular Physics, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4−6, 14195 Berlin, Germany
| | - Carla Kirschbaum
- Institute
of Chemistry and Biochemistry, Freie Universität
Berlin, Arnimallee 22, 14195 Berlin, Germany
- Department
of Molecular Physics, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4−6, 14195 Berlin, Germany
| | - Kim Greis
- Institute
of Chemistry and Biochemistry, Freie Universität
Berlin, Arnimallee 22, 14195 Berlin, Germany
- Department
of Molecular Physics, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4−6, 14195 Berlin, Germany
| | - Christian Manz
- Institute
of Chemistry and Biochemistry, Freie Universität
Berlin, Arnimallee 22, 14195 Berlin, Germany
- Department
of Molecular Physics, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4−6, 14195 Berlin, Germany
| | - Kevin Pagel
- Institute
of Chemistry and Biochemistry, Freie Universität
Berlin, Arnimallee 22, 14195 Berlin, Germany
- Department
of Molecular Physics, Fritz Haber Institute
of the Max Planck Society, Faradayweg 4−6, 14195 Berlin, Germany
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6
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Li W, Kavatsyuk O, Douma W, Wang X, Hoekstra R, Mayer D, Robinson MS, Gühr M, Lalande M, Abdelmouleh M, Ryszka M, Poully JC, Schlathölter T. Multiple valence electron detachment following Auger decay of inner-shell vacancies in gas-phase DNA. Chem Sci 2021; 12:13177-13186. [PMID: 34745549 PMCID: PMC8513815 DOI: 10.1039/d1sc02885e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/10/2021] [Indexed: 01/05/2023] Open
Abstract
We have studied soft X-ray photoabsorption in the doubly deprotonated gas-phase oligonucleotide [dTGGGGT–2H]2−. The dominating decay mechanism of the X-ray induced inner shell vacancy was found to be Auger decay with detachment of at least three electrons, leading to charge reversal of the anionic precursor and the formation of positively charged photofragment ions. The same process is observed in heavy ion (12 MeV C4+) collisions with [dTGGGGT–2H]2− where inner shell vacancies are generated as well, but with smaller probability. Auger decay of a single K-vacancy in DNA, followed by detachment of three or more low energy electrons instead of a single high energy electron has profound implications for DNA damage and damage modelling. The production of three low kinetic energy electrons with short mean free path instead of one high kinetic energy electron with long mean free path implies that electron-induced DNA damage will be much more localized around the initial K-shell vacancy. The fragmentation channels, triggered by triple electron detachment Auger decay are predominantly related to protonated guanine base loss and even loss of protonated guanine dimers is tentatively observed. The fragmentation is not a consequence of the initial K-shell vacancy but purely due to multiple detachment of valence electrons, as a very similar positive ion fragmentation pattern is observed in femtosecond laser-induced dissociation experiments. A K-shell vacancy in DNA that is induced by a (therapeutically relevant) soft X-ray of MeV carbon ion, decays by Auger processes accompanied by emission of at least 3 low energy electrons.![]()
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Affiliation(s)
- Wen Li
- University of Groningen, Zernike Institute for Advanced Materials Nijenborgh 4 9747AG Groningen Netherlands
| | - Oksana Kavatsyuk
- University College Groningen Hoendiep 23/24 9718BG Groningen Netherlands
| | - Wessel Douma
- University of Groningen, Zernike Institute for Advanced Materials Nijenborgh 4 9747AG Groningen Netherlands
| | - Xin Wang
- University of Groningen, Zernike Institute for Advanced Materials Nijenborgh 4 9747AG Groningen Netherlands
| | - Ronnie Hoekstra
- University of Groningen, Zernike Institute for Advanced Materials Nijenborgh 4 9747AG Groningen Netherlands
| | - Dennis Mayer
- Universität Potsdam, Institut für Physik und Astronomie 14476 Potsdam Germany
| | - Matthew S Robinson
- Universität Potsdam, Institut für Physik und Astronomie 14476 Potsdam Germany.,Centre for Free Electron Lasers (CFEL), DESY Notkestraße 85 22607 Hamburg Germany
| | - Markus Gühr
- Universität Potsdam, Institut für Physik und Astronomie 14476 Potsdam Germany
| | - Mathieu Lalande
- CIMAP UMR 6252 (CEA/CNRS/ENSICAEN/Université de Caen Normandie) Boulevard Becquerel 14070 Caen Cedex 5 France
| | - Marwa Abdelmouleh
- CIMAP UMR 6252 (CEA/CNRS/ENSICAEN/Université de Caen Normandie) Boulevard Becquerel 14070 Caen Cedex 5 France
| | - Michal Ryszka
- CIMAP UMR 6252 (CEA/CNRS/ENSICAEN/Université de Caen Normandie) Boulevard Becquerel 14070 Caen Cedex 5 France
| | - Jean Christophe Poully
- CIMAP UMR 6252 (CEA/CNRS/ENSICAEN/Université de Caen Normandie) Boulevard Becquerel 14070 Caen Cedex 5 France
| | - Thomas Schlathölter
- University of Groningen, Zernike Institute for Advanced Materials Nijenborgh 4 9747AG Groningen Netherlands
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7
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Gabelica V. Native Mass Spectrometry and Nucleic Acid G-Quadruplex Biophysics: Advancing Hand in Hand. Acc Chem Res 2021; 54:3691-3699. [PMID: 34546031 DOI: 10.1021/acs.accounts.1c00396] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
While studying nucleic acids to reveal the weak interactions responsible for their three-dimensional structure and for their interactions with drugs, we also contributed to the field of biomolecular mass spectrometry, both in terms of fundamental understanding and with new methodological developments. A first goal was to develop mass spectrometry approaches to detect noncovalent interactions between antitumor drugs and their DNA target. Twenty years ago, our attention turned toward specific DNA structures such as the G-quadruplex (a structure formed by guanine-rich strands). Mass spectrometry allows one to discern which molecules interact with one another by measuring the masses of the complexes, and quantify the affinities by measuring their abundance. The most important findings came from unexpected masses. For example, we showed the formation of higher- or lower-order structures by G-quadruplexes used in traditional biophysical assays. We also derived complete thermodynamic and kinetic description of G-quadruplex folding pathways by measuring cation binding, one at a time. Getting quantitative information requires accounting for nonspecific adduct formation and for the response factors of the different molecular forms. With these caveats in mind, the approach is now mature enough for routine biophysical characterization of nucleic acids. A second goal is to obtain more detailed structural information on each of the complexes separated by the mass spectrometer. One such approach is ion mobility spectrometry, and even today the challenge lies in the structural interpretation of the measurements. We showed that, although structures such as G-quadruplexes are well-preserved in the MS conditions, double helices actually get more compact in the gas phase. These major rearrangements forced us to challenge comfortable assumptions. Further work is still needed to generalize how to deduce structures in solution from ion mobility spectrometry data and, in particular, how to account for the electrospray charging mechanisms and for ion internal energy effects. These studies also called for complementary approaches to ion mobility spectrometry. Recently, we applied isotope exchange labeling mass spectrometry to characterize nucleic acid structures for the first time, and we reported the first ever circular dichroism ion spectroscopy measurement on mass-selected trapped ions. Circular dichroism plays a key role in assigning the stacking topology, and our new method now opens the door to characterizing a wide variety of chiral molecules by mass spectrometry. In summary, advanced mass spectrometry approaches to characterize gas-phase structures work well for G-quadruplexes because they are stiffened by inner cations. The next objective will be to generalize these methodologies to a wider range of nucleic acid structures.
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Affiliation(s)
- Valérie Gabelica
- Université de Bordeaux, CNRS, INSERM,
ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
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8
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Largy E, König A, Ghosh A, Ghosh D, Benabou S, Rosu F, Gabelica V. Mass Spectrometry of Nucleic Acid Noncovalent Complexes. Chem Rev 2021; 122:7720-7839. [PMID: 34587741 DOI: 10.1021/acs.chemrev.1c00386] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nucleic acids have been among the first targets for antitumor drugs and antibiotics. With the unveiling of new biological roles in regulation of gene expression, specific DNA and RNA structures have become very attractive targets, especially when the corresponding proteins are undruggable. Biophysical assays to assess target structure as well as ligand binding stoichiometry, affinity, specificity, and binding modes are part of the drug development process. Mass spectrometry offers unique advantages as a biophysical method owing to its ability to distinguish each stoichiometry present in a mixture. In addition, advanced mass spectrometry approaches (reactive probing, fragmentation techniques, ion mobility spectrometry, ion spectroscopy) provide more detailed information on the complexes. Here, we review the fundamentals of mass spectrometry and all its particularities when studying noncovalent nucleic acid structures, and then review what has been learned thanks to mass spectrometry on nucleic acid structures, self-assemblies (e.g., duplexes or G-quadruplexes), and their complexes with ligands.
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Affiliation(s)
- Eric Largy
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Alexander König
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Anirban Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Debasmita Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Sanae Benabou
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Frédéric Rosu
- Univ. Bordeaux, CNRS, INSERM, IECB, UMS 3033, F-33600 Pessac, France
| | - Valérie Gabelica
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
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9
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Wong NK, Rankine CD, Dessent CEH. Linking Electronic Relaxation Dynamics and Ionic Photofragmentation Patterns for the Deprotonated UV Filter Benzophenone-4. J Phys Chem Lett 2021; 12:2831-2836. [PMID: 33719458 PMCID: PMC8041369 DOI: 10.1021/acs.jpclett.1c00423] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Understanding how deprotonation impacts the photophysics of UV filters is critical to better characterize how they behave in key alkaline environments including surface waters and coral reefs. Using anion photodissociation spectroscopy, we have measured the intrinsic absorption electronic spectroscopy (400-214 nm) and numerous accompanying ionic photofragmentation pathways of the benzophenone-4 anion ([BP4-H]-). Relative ion yield plots reveal the locations of the bright S1 and S3 excited states. For the first time for an ionic UV filter, ab initio potential energy surfaces are presented to provide new insight into how the photofragment identity maps the relaxation pathways. These calculations reveal that [BP4-H]- undergoes excited-state decay consistent with a statistical fragmentation process where the anion breaks down on the ground state after nonradiative relaxation. The broader relevance of the results in providing a basis for interpreting the relaxation dynamics of a wide range of gas-phase ionic systems is discussed.
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Affiliation(s)
- Natalie
G. K. Wong
- Department
of Chemistry, University of York, Heslington, York, YO10 5DD, U.K.
| | - Conor D. Rankine
- School
of Natural and Environmental Sciences, Newcastle
University, Newcastle-upon-Tyne, NE1 7RU, U.K.
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10
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Uleanya KO, Dessent CEH. Investigating the mapping of chromophore excitations onto the electron detachment spectrum: photodissociation spectroscopy of iodide ion-thiouracil clusters. Phys Chem Chem Phys 2021; 23:1021-1030. [PMID: 33428696 DOI: 10.1039/d0cp05920j] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Laser photodissociation spectroscopy (3.1-5.7 eV) has been applied to iodide complexes of the non-native nucleobases, 2-thiouracil (2-TU), 4-thiouracil (4-TU) and 2,4-thiouracil (2,4-TU), to probe the excited states and intracluster electron transfer as a function of sulphur atom substitution. Photodepletion is strong for all clusters (I-·2-TU, I-·4-TU and I-·2,4-TU) and is dominated by electron detachment processes. For I-·4-TU and I-·2,4-TU, photodecay is accompanied by formation of the respective molecular anions, 4-TU- and 2,4-TU-, behaviour that is not found for other nucleobases. Notably, the I-·2TU complex does not fragment with formation of its molecular anion. We attribute the novel formation of 4-TU- and 2,4-TU- to the fact that these valence anions are significantly more stable than 2-TU-. We observe further similar behaviour for I-·4-TU and I-·2,4-TU relating to the general profile of their photodepletion spectra, since both strongly resemble the intrinsic absorption spectra of the respective uncomplexed thiouracil molecule. This indicates that the nucleobase chromophore excitations are determining the clusters' spectral profile. In contrast, the I-·2-TU photodepletion spectrum is dominated by the electron detachment profile, with the near-threshold dipole-bound excited state being the only distinct spectral feature. We discuss these observations in the context of differences in the dipole moments of the thionucleobases, and their impact on the coupling of nucleobase-centred transitions onto the electron detachment spectrum.
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Affiliation(s)
- Kelechi O Uleanya
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
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11
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Castellani ME, Avagliano D, González L, Verlet JRR. Site-Specific Photo-oxidation of the Isolated Adenosine-5'-triphosphate Dianion Determined by Photoelectron Imaging. J Phys Chem Lett 2020; 11:8195-8201. [PMID: 32886886 DOI: 10.1021/acs.jpclett.0c02089] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Photoelectron imaging of the isolated adenosine-5'-triphosphate dianion excited to the 1ππ* states reveals that electron emission is predominantly parallel to the polarization axis of the light and arises from subpicosecond electron tunneling through the repulsive Coulomb barrier (RCB). The computed RCB shows that the most probable electron emission site is on the amino group of adenine. This is consistent with the photoelectron imaging: excitation to the 1ππ* states leads to an aligned ensemble distributed predominantly parallel to the long axis of adenine; the subsequent electron tunneling site is along this axis; and the negatively charged phosphate groups guide the outgoing electron mostly along this axis at long range. Imaging of electron tunneling from polyanions combined with computational chemistry may offer a general route for probing the intrinsic photo-oxidation site and dynamics as well as the overall structure of complex isolated species.
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Affiliation(s)
| | - Davide Avagliano
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
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12
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Balanikas E, Banyasz A, Douki T, Baldacchino G, Markovitsi D. Guanine Radicals Induced in DNA by Low-Energy Photoionization. Acc Chem Res 2020; 53:1511-1519. [PMID: 32786340 DOI: 10.1021/acs.accounts.0c00245] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Guanine (G) radicals are precursors to DNA oxidative damage, correlated with carcinogenesis and aging. During the past few years, we demonstrated clearly an intriguing effect: G radicals can be generated upon direct absorption of UV radiation with energy significantly lower than the G ionization potential. Using nanosecond transient absorption spectroscopy, we studied the primary species, ejected electrons and guanine radicals, which result from photoionization of various DNA systems in aqueous solution.The DNA propensity to undergo electron detachment at low photon energies greatly depends on its secondary structure. Undetected for monomers or unstacked oligomers, this propensity may be 1 order of magnitude higher for G-quadruplexes than for duplexes. The experimental results suggest nonvertical processes, associated with the relaxation of electronic excited states. Theoretical studies are required to validate the mechanism and determine the factors that come into play. Such a mechanism, which may be operative over a broad excitation wavelength range, explains the occurrence of oxidative damage observed upon UVB and UVA irradiation.Quantification of G radical populations and their time evolution questions some widespread views. It appears that G radicals may be generated with the same probability as pyrimidine dimers, which are considered to be the major lesions induced upon absorption of low-energy UV radiation by DNA. As most radical cations undergo deprotonation, the vast majority of the final reaction products is expected to stem from long-lived deprotonated radicals. Consequently, when G radical cations are involved, the widely used oxidation marker 8-oxodG is not representative of the oxidative damage.Beyond the biological consequences, photogeneration of electron holes in G-quadruplexes may inspire applications in nanoelectronics; although four-stranded structures are currently studied as molecular wires, their behavior as photoconductors has not been explored so far.In the present Account, after highlighting some key experimental issues, we first describe the photoionization process, and then, we focus on radicals. We use as show-cases new results obtained for genomic DNA and Oxytricha G-quadruplexes. Generation and reaction dynamics of G radicals in these systems provide a representative picture of the phenomena reported previously for duplexes and G-quadruplexes, respectively.
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Affiliation(s)
| | - Akos Banyasz
- Univ Lyon, ENS de Lyon, CNRS UMR 5182, Université Claude Bernard Lyon 1, Laboratoire de Chimie, F-69342 Lyon, France
| | - Thierry Douki
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, F-38000 Grenoble France
| | - Gérard Baldacchino
- Université Paris-Saclay, CEA, CNRS, LIDYL, F-91191 Gif-sur-Yvette, France
| | - Dimitra Markovitsi
- Université Paris-Saclay, CEA, CNRS, LIDYL, F-91191 Gif-sur-Yvette, France
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Daly S, Rosu F, Gabelica V. Mass-resolved electronic circular dichroism ion spectroscopy. Science 2020; 368:1465-1468. [PMID: 32587016 DOI: 10.1126/science.abb1822] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/27/2020] [Indexed: 12/15/2022]
Abstract
DNA and proteins are chiral: Their three-dimensional structures cannot be superimposed with their mirror images. Circular dichroism spectroscopy is widely used to characterize chiral compounds, but data interpretation is difficult in the case of mixtures. We recorded the electronic circular dichroism spectra of DNA helices separated in a mass spectrometer. We studied guanine-rich strands having various secondary structures, electrosprayed them as negative ions, irradiated them with an ultraviolet nanosecond optical parametric oscillator laser, and measured the difference in electron photodetachment efficiency between left and right circularly polarized light. The reconstructed circular dichroism ion spectra resembled those of their solution-phase counterparts, thereby allowing us to assign the DNA helical topology. The ability to measure circular dichroism directly on biomolecular ions expands the capabilities of mass spectrometry for structural analysis.
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Affiliation(s)
- Steven Daly
- Université de Bordeaux, Inserm & CNRS, Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle (ARNA, U1212, UMR5320), IECB, 33607 Pessac, France
| | - Frédéric Rosu
- Université de Bordeaux, CNRS & Inserm, Institut Européen de Chimie et Biologie (IECB, UMS3033, US001), 33607 Pessac, France
| | - Valérie Gabelica
- Université de Bordeaux, Inserm & CNRS, Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle (ARNA, U1212, UMR5320), IECB, 33607 Pessac, France.
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14
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Largy E, Gabelica V. Native Hydrogen/Deuterium Exchange Mass Spectrometry of Structured DNA Oligonucleotides. Anal Chem 2020; 92:4402-4410. [PMID: 32039580 DOI: 10.1021/acs.analchem.9b05298] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although solution hydrogen-deuterium exchange mass spectrometry (HDX/MS) is well-established for the analysis of the structure and dynamics of proteins, it is currently not exploited for nucleic acids. Here we used DNA G-quadruplex structures as model systems to demonstrate that DNA oligonucleotides are amenable to in-solution HDX/MS in native conditions. In trimethylammonium acetate solutions and in soft source conditions, the protonated phosphate groups are fully back-exchanged in the source, while the exchanged nucleobases remain labeled without detectable back-exchange. As a result, the exchange rates depend strongly on the secondary structure (hydrogen bonding status) of the oligonucleotides, but neither on their charge state nor on the presence of nonspecific adducts. We show that native mass spectrometry methods can measure these exchange rates on the second to the day time scale with high precision. Such combination of HDX with native MS opens promising avenues for the analysis of the structural and biophysical properties of oligonucleotides and their complexes.
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Affiliation(s)
- Eric Largy
- University of Bordeaux, INSERM and CNRS, Laboratoires Acides Nucléiques: Régulations Naturelle et Artificielle (ARNA, U1212, UMR5320), IECB, 2 rue Robert Escarpit, 33600 Pessac, France
| | - Valérie Gabelica
- University of Bordeaux, INSERM and CNRS, Laboratoires Acides Nucléiques: Régulations Naturelle et Artificielle (ARNA, U1212, UMR5320), IECB, 2 rue Robert Escarpit, 33600 Pessac, France
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15
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Behmand B, Balanikas E, Martinez-Fernandez L, Improta R, Banyasz A, Baldacchino G, Markovitsi D. Potassium Ions Enhance Guanine Radical Generation upon Absorption of Low-Energy Photons by G-Quadruplexes and Modify Their Reactivity. J Phys Chem Lett 2020; 11:1305-1309. [PMID: 31967478 DOI: 10.1021/acs.jpclett.9b03667] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
G-Quadruplexes are formed by guanine rich DNA/RNA sequences in the presence of metal ions, which occupy the central cavity of these four-stranded structures. We show that these metal ions have a significant effect on the photogeneration and the reactivity of guanine radicals. Transient absorption experiments on G-quadruplexes formed by association of four TGGGGT strands in the presence of K+ reveal that the quantum yield of one-photon ionization at 266 nm (8.1 × 10-3) is twice as high as that determined in the presence of Na+. Replacement of Na+ with K+ also suppresses one reaction path involving deprotonated radicals, (G-H2)• → (G-H1)• tautomerization. Such behavior shows that the underlying mechanisms are governed by dynamical processes, controlled by the mobility of metal ions, which is higher for Na+ than for K+. These findings may contribute to our understanding of the ultraviolet-induced DNA damage and optimize optoelectronic devices based on four-stranded structures, beyond DNA.
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Affiliation(s)
- Behnaz Behmand
- Université Paris-Saclay , CEA, CNRS, LIDYL , F-91191 Gif-sur-Yvette , France
| | - Evangelos Balanikas
- Université Paris-Saclay , CEA, CNRS, LIDYL , F-91191 Gif-sur-Yvette , France
| | - Lara Martinez-Fernandez
- Departamento de Quı́mica, Facultad de Ciencias , Universidad Autónoma de Madrid , 28049 Cantoblanco , Spain
- IADCHEM, Institute for Advanced Research in Chemistry , Universidad Autónoma de Madrid , 28049 Cantoblanco , Spain
| | - Roberto Improta
- Istituto Biostrutture e Bioimmagini-Consiglio Nazionale delle Ricerche , Via Mezzocannone 16 , I-80134 Napoli , Italy
| | - Akos Banyasz
- Univ Lyon, ENS de Lyon, CNRS UMR 5182 , Université Claude Bernard Lyon 1, Laboratoire de Chimie , F-69342 Lyon , France
| | - Gérard Baldacchino
- Université Paris-Saclay , CEA, CNRS, LIDYL , F-91191 Gif-sur-Yvette , France
| | - Dimitra Markovitsi
- Université Paris-Saclay , CEA, CNRS, LIDYL , F-91191 Gif-sur-Yvette , France
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Zagorec-Marks W, Smith JET, Foreman MM, Sharma S, Weber JM. Intrinsic electronic spectra of cryogenically prepared protoporphyrin IX ions in vacuo – deprotonation-induced Stark shifts. Phys Chem Chem Phys 2020; 22:20295-20302. [DOI: 10.1039/d0cp03614e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present electronic spectra containing the Qx and Qy absorption bands of singly and doubly deprotonated protoporphyrin IX, prepared as mass selected ions in vacuo at cryogenic temperatures, revealing vibronic structure of both bands.
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