1
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Moe MM, Tsai M, Liu J. Effects of Intra-Base Pair Proton Transfer on Dissociation and Singlet Oxygenation of 9-Methyl-8-Oxoguanine-1-Methyl-Cytosine Base-Pair Radical Cations. Chemphyschem 2023; 24:e202300511. [PMID: 37738022 DOI: 10.1002/cphc.202300511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/18/2023] [Accepted: 09/22/2023] [Indexed: 09/23/2023]
Abstract
8-Oxoguanosine is the most common oxidatively generated base damage and pairs with complementary cytidine within duplex DNA. The 8-oxoguanosine-cytidine lesion, if not recognized and removed, not only leads to G-to-T transversion mutations but renders the base pair being more vulnerable to the ionizing radiation and singlet oxygen (1 O2 ) damage. Herein, reaction dynamics of a prototype Watson-Crick base pair [9MOG ⋅ 1MC]⋅+ , consisting of 9-methyl-8-oxoguanine radical cation (9MOG⋅+ ) and 1-methylcystosine (1MC), was examined using mass spectrometry coupled with electrospray ionization. We first detected base-pair dissociation in collisions with the Xe gas, which provided insight into intra-base pair proton transfer of 9MOG⋅+ ⋅ 1MC← → ${{\stackrel{ {\rightarrow} } { {\leftarrow} } } }$ [9MOG - HN1 ]⋅ ⋅ [1MC+HN3' ]+ and subsequent non-statistical base-pair separation. We then measured the reaction of [9MOG ⋅ 1MC]⋅+ with 1 O2 , revealing the two most probable pathways, C5-O2 addition and HN7 -abstraction at 9MOG. Reactions were entangled with the two forms of 9MOG radicals and base-pair structures as well as multi-configurations between open-shell radicals and 1 O2 (that has a mixed singlet/triplet character). These were disentangled by utilizing approximately spin-projected density functional theory, coupled-cluster theory and multi-referential electronic structure modeling. The work delineated base-pair structural context effects and determined relative reactivity toward 1 O2 as [9MOG - H]⋅>9MOG⋅+ >[9MOG - HN1 ]⋅ ⋅ [1MC+HN3' ]+ ≥9MOG⋅+ ⋅ 1MC.
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Affiliation(s)
- May Myat Moe
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY 11367, USA
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, NY 10016, USA
| | - Midas Tsai
- Department of Natural Sciences, LaGuardia Community College, 31-10 Thomson Ave., Long Island City, NY 11101, USA
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY 11367, USA
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, NY 10016, USA
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2
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Kou M, Jiao L, Xu S, Du M, Hou Y, Kong X. Structural Characterization of the Metalized Radical Cations of Adenosine ([Ade+Li-H] •+ and [Ade+Na-H] •+) by Infrared Multiphoton Dissociation Spectroscopy and Theoretical Studies. Int J Mol Sci 2023; 24:15385. [PMID: 37895065 PMCID: PMC10607295 DOI: 10.3390/ijms242015385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
Nucleoside radicals are key intermediates in the process of DNA damage, and alkali metal ions are a common group of ions in living organisms. However, so far, there has been a significant lack of research on the structural effects of alkali metal ions on nucleoside free radicals. In this study, we report a new method for generating metalized nucleoside radical cations in the gas phase. The radical cations [Ade+M-H]•+ (M = Li, Na) are generated by the 280 nm ultraviolet photodissociation (UVPD) of the precursor ions of lithiated and sodiated ions of 2-iodoadenine in a Fourier transform ion cyclotron resonance (FT ICR) cell. Further infrared multiphoton dissociation (IRMPD) spectra of both radical cations were recorded in the region of 2750-3750 cm-1. By combining these results with theoretical calculations, the most stable isomers of both radicals can be identified, which share the common characteristics of triple coordination patterns of the metal ions. For both radical species, the lowest-energy isomers undergo hydrogen transfer. Although the sugar ring in the most stable isomer of [Ade+Li-H]•+ is in a (South, syn) conformation similar to that of [Ado+Na]+, [Ade+Na-H]•+ is distinguished by the unexpected opening of the sugar ring. Their theoretical spectra are in good agreement with experimental spectra. However, due to the flexibility of the structures and the complexity of their potential energy surfaces, the hydrogen transfer pathways still need to be further studied. Considering that the free radicals formed directly after C-I cleavage have some similar spectral characteristics, the existence of these corresponding isomers cannot be ruled out. The findings imply that the structures of nucleoside radicals may be significantly influenced by the attached alkali metal ions. More detailed experiments and theoretical calculations are still crucial.
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Affiliation(s)
- Min Kou
- State Key Laboratory of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Luyang Jiao
- State Key Laboratory of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Shiyin Xu
- State Key Laboratory of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Mengying Du
- State Key Laboratory of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Yameng Hou
- State Key Laboratory of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Xianglei Kong
- State Key Laboratory of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin 300071, China
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3
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Zima V, Vlk M, Wan J, Cvačka J, Tureček F. Tracking Isomerizations of High-Energy Adenine Cation Radicals by UV-Vis Action Spectroscopy and Cyclic Ion Mobility Mass Spectrometry. J Phys Chem A 2023. [PMID: 37433135 DOI: 10.1021/acs.jpca.3c03179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
We report experimental and computational studies of protonated adenine C-8 σ-radicals that are presumed yet elusive reactive intermediates of oxidative damage to nucleic acids. The radicals were generated in the gas phase by the collision-induced dissociation of C-8-Br and C-8-I bonds in protonated 8-bromo- and 8-iodoadenine as well as by 8-bromo- and 8-iodo-9-methyladenine. Protonation by electrospray of 8-bromo- and 8-iodoadenine was shown by cyclic-ion mobility mass spectrometry (c-IMS) to form the N-1-H, N-9-H and N-3-H, N-7-H protomers in 85:15 and 81:19 ratios, respectively, in accordance with the equilibrium populations of these protomers in water-solvated ions that were calculated by density functional theory (DFT). Protonation of 8-halogenated 9-methyladenines yielded single N-1-H protomers, which was consistent with their thermodynamic stability. The radicals produced from the 8-bromo and 8-iodo adenine cations were characterized by UV-vis photodissociation action spectroscopy (UVPD) and c-IMS. UVPD revealed the formation of C-8 σ-radicals along with N-3-H, N-7-H-adenine π-radicals that arose as secondary products by hydrogen atom migrations. The isomers were identified by matching their action spectra against the calculated vibronic absorption spectra. Deuterium isotope effects were found to slow the isomerization and increase the population of C-8 σ-radicals. The adenine cation radicals were separated by c-IMS and identified by their collision cross sections, which were measured relative to the canonical N-9-H adenine cation radical that was cogenerated in situ as an internal standard. Ab initio CCSD(T)/CBS calculations of isomer energies showed that the adenine C-8 σ-radicals were local energy minima with relative energies at 76-79 kJ mol-1 above that of the canonical adenine cation radical. Rice-Ramsperger-Kassel-Marcus calculations of unimolecular rate constants for hydrogen and deuterium migrations resulting in exergonic isomerizations showed kinetic shifts of 10-17 kJ mol-1, stabilizing the C-8 σ-radicals. C-8 σ-radicals derived from N-1-protonated 9-methyladenine were also thermodynamically unstable and readily isomerized upon formation.
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Affiliation(s)
- Václav Zima
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Mikuláš Vlk
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
- Department of Analytical Chemistry, Faculty of Science, Charles University, 12800 Prague, Czech Republic
| | - Jiahao Wan
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
- Department of Analytical Chemistry, Faculty of Science, Charles University, 12800 Prague, Czech Republic
| | - František Tureček
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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Skelton E, Erasquin U, Sukul A, Zuercher A, White J, Bythell BJ, Cimatu KLA. Visible Light-Assisted Coordination of a Rh(III)-BODIPY Complex to Guanine. Inorg Chem 2023; 62:3368-3380. [PMID: 36795094 DOI: 10.1021/acs.inorgchem.2c03289] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Most photodynamic therapeutics (PDTs) used in cancer treatment require oxygen to work efficiently to terminate cancer cells. These PDTs do not efficiently treat tumors in hypoxic conditions. Rh(III) polypyridyl complexes have been reported to have a photodynamic therapeutic effect in hypoxic conditions when exposed to UV light. UV light can damage tissue and cannot penetrate deep to reach cancer cells. This work proposes the coordination of a BODIPY fluorophore to a rhodium metal center to form a Rh(III)-BODIPY complex that enhances the reactivity of the rhodium under visible light. This complex formation is facilitated with the BODIPY as the highest occupied molecular orbital (HOMO), while the lowest unoccupied molecular orbital (LUMO) is localized on the Rh(III) metal center. Irradiation of the BODIPY transition at ∼524 nm can cause an indirect electron transfer from the orbital of the BODIPY-centered HOMO to the Rh(III)-centered LUMO, populating the dσ* orbital. In addition, photo binding of the Rh complex covalently coordinated to the N (7) position of guanine in an aqueous solution was also observed by mass spectrometry after chloride dissociation upon irradiation with green visible light (532 nm LED). Calculated thermochemistry values of the Rh complex reaction in methanol, acetonitrile, water, and guanine were determined using DFT calculations. All enthalpic reactions and Gibbs free energies were identified as endothermic and nonspontaneous, respectively. This observation supports the chloride dissociation using 532 nm light. This Rh(III)-BODIPY complex expands the class of visible light-activated Rh(III) photocisplatin analogs that may have potential photodynamic therapeutic activity for the treatment of cancers in hypoxic conditions.
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Affiliation(s)
- Eli Skelton
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Uriel Erasquin
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Abhijit Sukul
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Aoife Zuercher
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Jessica White
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Benjamin J Bythell
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Katherine Leslee Asetre Cimatu
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
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5
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Wan J, Brož B, Liu Y, Huang SR, Marek A, Tureček F. The DNA Radical Code. Resolution of Identity in Dissociations of Trinucleotide Codon Cation Radicals in the Gas Phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:304-319. [PMID: 36596259 DOI: 10.1021/jasms.2c00322] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Sixty DNA trinucleotide cation radicals covering a large part of the genetic code alphabet were generated by electron transfer in the gas phase, and their chemistry was studied by collision-induced dissociation tandem mass spectrometry and theoretical calculations. The major dissociations involved loss of nucleobase molecules and radicals, backbone cleavage, and cross-ring fragmentations that depended on the nature and position of the nucleobases. Mass identity in dissociations of symmetrical trinucleotide cation radicals of the (XXX+2H)+• and (XYX+2H)+• type was resolved by specific 15N labeling. The specific features of trinucleotide cation radical dissociations involved the dominant formation of d2+ ions, hydrogen atom migrations accompanying the formation of (w2+H)+•, (w2+2H)+, and (d2+2H)+ sequence ions, and cross-ring cleavages in the 3'- and 5'-deoxyribose moieties that depended on the nucleobase type and its position in the ion. Born-Oppenheimer molecular dynamics (BOMD) and density functional theory calculations were used to obtain structures and energies of several cation-radical protomers and conformers for (AAA+2H)+•, (CCC+2H)+•, (GGG+2H)+•, (ACA+2H)+•, and (CAA+2H)+• that were representative of the different types of backbone dissociations. The ion electronic structure, protonation and radical sites, and hydrogen bonding were used to propose reaction mechanisms for the dissociations.
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Affiliation(s)
- Jiahao Wan
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
| | - Břetislav Brož
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - Yue Liu
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
| | - Shu R Huang
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
| | - Aleš Marek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - František Tureček
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
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6
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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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7
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Moe MM, Saito T, Tsai M, Liu J. Singlet O 2 Oxidation of the Radical Cation versus the Dehydrogenated Neutral Radical of 9-Methylguanine in a Watson-Crick Base Pair. Consequences of Structural Context. J Phys Chem B 2022; 126:5458-5472. [PMID: 35849846 DOI: 10.1021/acs.jpcb.2c03748] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In DNA, guanine is the most susceptible to oxidative damage by exogenously and endogenously produced electronically excited singlet oxygen (1O2). The reaction mechanism and the product outcome strongly depend on the nucleobase ionization state and structural context. Previously, exposure of a monomeric 9-methylguanine radical cation (9MG•+, a model guanosine compound) to 1O2 was found to result in the formation of an 8-peroxide as the initial product. The present work explores the 1O2 oxidation of 9MG•+ and its dehydrogenated neutral form [9MG - H]• within a Watson-Crick base pair consisting of one-electron-oxidized 9-methylguanine-1-methylcytosine [9MG·1MC]•+. Emphasis is placed on entangling the base pair structural context and intra-base pair proton transfer with and consequences thereof on the singlet oxygenation of guanine radical species. Electrospray ionization coupled with guided-ion beam tandem mass spectrometry was used to study the formation and reaction of guanine radical species in the gas phase. The 1O2 oxidation of both 9MG•+ and [9MG - H]• is exothermic and proceeds barrierlessly either in an isolated monomer or within a base pair. Single- and multi-referential theories were tested for treating spin contaminations and multi-configurations occurring in radical-1O2 interactions, and reaction potential energy surfaces were mapped out to support experimental findings. The work provides a comprehensive profile for the singlet oxygenation of guanine radicals in different charge states and in the absence and the presence of base pairing. All results point to an 8-peroxide as the major oxidation product in the experiment, and the oxidation becomes slightly more favorable in a neutral radical form. On the basis of a variety of reaction pathways and product profiles observed in the present and previous studies, the interplay between guanine structure, base pairing, and singlet oxygenation and its biological implications are discussed.
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Affiliation(s)
- May Myat Moe
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
| | - Toru Saito
- Department of Biomedical Information Science, Graduate School of Information Science, Hiroshima City University, 3-4-1 Ozuka-Higashi, Asa-Minami-Ku, 731-3194 Hiroshima, Japan
| | - Midas Tsai
- Department of Natural Sciences, LaGuardia Community College, 31-10 Thomson Avenue, Long Island City, New York 11101, United States
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
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8
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Zima V, Liu Y, Tureček F. Radical Cascade Dissociation Pathways to Unusual Nucleobase Cation Radicals. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1038-1047. [PMID: 35536606 DOI: 10.1021/jasms.2c00098] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We report unusual dissociations of protonated RNA nucleosides tagged with radical initiator groups at ribose 5'-O and furnished with a 2',3'-O-isopropylidene protecting group. The ions undergo collision-induced radical cascade dissociations starting at the radical initiator that break down the dioxolane ring and trigger the formation of nucleobase cations and cation radicals. The adenine cation radical that was formed by radical cascade dissociations was identified by MS5 UV-vis photodissociation action spectroscopy to be a higher-energy N-3-H tautomer of the canonical ionized nucleobase. The guanine cation radical was formed by radical cascade dissociations as the N-7-H tautomer. In contrast to adenosine and guanosine, radical cascade dissociations of the tagged ribocytidine ion produced protonated cytosine, whereas tagged ribothymidine showed yet different dissociations resulting in predominant thymine loss. Reaction mechanisms were suggested for the cascade dissociations that were based on Born-Oppenheimer molecular dynamics and density functional theory calculations that were used to map the relevant parts of the potential energy surfaces for adenosine, guanosine, and cytidine radical ions. The reported radical cascade dissociations represent a new, nonredox approach to nucleobase and nucleoside cation radicals that has the potential of being expanded to the generation of various oligonucleotide cation radicals.
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Affiliation(s)
- Václav Zima
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 981195-1700, United States
| | - Yue Liu
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 981195-1700, United States
| | - František Tureček
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 981195-1700, United States
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Moe MM, Tsai M, Liu J. Singlet Oxygen Oxidation of the Radical Cations of 8-Oxo-2'-deoxyguanosine and Its 9-Methyl Analogue: Dynamics, Potential Energy Surface, and Products Mediated by C5-O 2 -Addition. Chempluschem 2021; 86:1243-1254. [PMID: 34268890 DOI: 10.1002/cplu.202100238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/02/2021] [Indexed: 01/24/2023]
Abstract
8-Oxo-2'-deoxyguanosine (OG) is the most common DNA lesion. Notably, OG becomes more susceptible to oxidative damage than the undamaged nucleoside, forming mutagenic products in vivo. Herein the reactions of singlet O2 with the radical cations of 8-oxo-2'-deoxyguanosine (OG.+ ) and 9-methyl-8-oxoguanine (9MOG.+ ) were investigated using ion-molecule scattering mass spectrometry, from which barrierless, exothermic O2 -addition products were detected for both reaction systems. Corroborated by static reaction potential energy surface constructed using multi-reference CASPT2 theory and molecular dynamics simulated in the presence of the reactants' kinetic and internal energies, the C5-terminal O2 -addition was pinpointed as the most probable reaction pathway. By elucidating the reaction mechanism, kinetics and dynamics, and reaction products and energetics, this work constitutes the first report unraveling the synergetic damage of OG by ionizing radiation and singlet O2 .
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Affiliation(s)
- May Myat Moe
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY, 11367, USA.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, NY, 10016, USA
| | - Midas Tsai
- Department of Natural Sciences, LaGuardia Community College, 31-10 Thomson Ave., Long Island City, NY, 11101, USA
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY, 11367, USA.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, NY, 10016, USA
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10
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Tureček F. Flying DNA Cation Radicals in the Gas Phase: Generation and Action Spectroscopy of Canonical and Noncanonical Nucleobase Forms. J Phys Chem B 2021; 125:7090-7100. [PMID: 34166596 DOI: 10.1021/acs.jpcb.1c03674] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gas-phase chemistry of cation radicals related to ionized nucleic acids has enjoyed significant recent progress thanks to the development of new methods for cation radical generation, ion spectroscopy, and reactivity studies. Oxidative methods based on intramolecular electron transfer in transition-metal complexes have been used to generate nucleobase and nucleoside cation radicals. Reductive methods relying on intermolecular electron transfer in gas-phase ion-ion reactions have been utilized to generate a number of di- and tetranucleotide cation radicals, as well as charge-tagged nucleoside radicals. The generated cation radicals have been studied by infrared and UV-visible action spectroscopy and ab initio and density functional theory calculations, providing optimized structures, harmonic frequencies, and excited-state analysis. This has led to the discovery of stable noncanonical nucleobase cation radicals of unusual electronic properties and extremely low ion-electron recombination energies. Intramolecular proton-transfer reactions in cation radical oligonucleotides and Watson-Crick nucleoside pairs have been studied experimentally, and their mechanisms have been elucidated by theory. Whereas the range of applications of the oxidative methods is currently limited to nucleobases and readily oxidizable guanosine, the reductive methods can be scaled up to generate large oligonucleotide cation radicals including double-strand DNA. Challenges in the experimental and computational approach to DNA cation radicals are discussed.
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Affiliation(s)
- František Tureček
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
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11
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Huang SR, Tureček F. Cation Radicals of Hachimoji Nucleobases P and Z: Generation in the Gas Phase and Characterization by UV-Vis Photodissociation Action Spectroscopy and Theory. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:373-386. [PMID: 33206519 DOI: 10.1021/jasms.0c00381] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report the generation of gas-phase cation radicals of unusual nucleobases 5-aza-7-deazaguanine (P) and 6-amino-5-nitro-(1H)pyrid-2-one (Z) that have been used as building blocks of base-expanded (hachimoji) DNA. The cation radicals were generated by collision-induced intramolecular electron transfer and dissociation of ternary copper-terpyridine complexes. The cation radicals were characterized by deuterium labeling and tandem mass spectrometry including MS3 collision-induced dissociation, UV-vis photodissociation, and action spectroscopy. Vibronic absorption UV-vis spectra were calculated by time-dependent density functional theory (TD-DFT) and compared with the action spectra to unequivocally assign the most closely matching structures for the gas-phase cation radicals. Ab initio calculations up to the coupled clusters-complete basis set (CCSD(T)/CBS) level of theory were used to rank by energy the P and Z neutral molecules and cation-radical isomers and provided transition-state and dissociation energies. The 5-aza-7-deazaguanine cation radicals were determined to have the canonical N-1-H, 6-oxo structure (P1+•) that was the global energy minimum within this group of isomers. The Z cation radicals were found to have the 1H-pyrid-2-one structure (Z1+•). The formation of P1+• and Z1+• was shown to be controlled by the solution thermodynamics of the Cu-terpyridine complexes and the kinetics of their dissociations. We also report and compare CCSD(T)/CBS-calculated adiabatic recombination energies of cation radicals for the entire hachimoji set of eight nucleobases, P+• (7.92 eV), Z+• (8.51 eV), S+• (8.51 eV), B+• (7.76 eV), T+• (8.98 eV), C+• (8.62 eV), A+• (8.32 eV), and G+• (7.97 eV), to assess the thermodynamics of base-to-base electron transfer following random ionization.
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Affiliation(s)
- Shu R Huang
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - František Tureček
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
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12
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Huang SR, Tureček F. Cation Radicals of Hachimoji Nucleobases. Canonical Purine and Noncanonical Pyrimidine Forms Generated in the Gas Phase and Characterized by UV–Vis Photodissociation Action Spectroscopy. J Phys Chem A 2020; 124:7101-7112. [DOI: 10.1021/acs.jpca.0c06227] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shu R. Huang
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - František Tureček
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
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13
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Huang SR, Dang A, Tureček F. Ground and Excited States of Gas-Phase DNA Nucleobase Cation-Radicals. A UV-vis Photodisociation Action Spectroscopy and Computational Study of Adenine and 9-Methyladenine. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:1271-1281. [PMID: 32324398 DOI: 10.1021/jasms.0c00095] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cation radicals of adenine (A•+) and 9-methyladenine (MA•+) were generated in the gas phase by collision-induced intramolecular electron transfer in copper-terpyridine-nucleobase ternary complexes and characterized by collision-induced dissociation (CID) mass spectra and UV-vis photodissociation action spectroscopy in the 210-700 nm wavelength region. The action spectra of both A•+ and MA•+ displayed characteristic absorption bands in the near-UV and visible regions. Another tautomer of A•+ was generated as a minor product by multistep CID of protonated 9-(2-bromoethyl)adenine. Structure analysis by density functional theory and coupled-clusters ab initio calculations pointed to the canonical 9-H-tautomer Ad1•+ as the global energy minimum of adenine cation radicals. The canonical tautomer MA1•+ was also calculated to be a low-energy structure among methyladenine cation radicals. However, two new noncanonical tautomers were found to be energetically comparable to MA1•+. Vibronic absorption spectra were calculated for several tautomers of A•+ and MA•+ and benchmarked on equation-of-motion coupled-clusters excited-state calculations. Analysis of the vibronic absorption spectra of A•+ tautomers pointed to the canonical tautomer Ad1•+ as providing the best match with the action spectrum. Likewise, the canonical tautomer MA1•+ was the unequivocal best match for the MA•+ ion generated in the gas phase. According to potential-energy mapping, MA1•+ was separated from energetically favorable noncanonical cation radicals by a high-energy barrier that was calculated to be above the dissociation threshold for loss of a methyl hydrogen atom, thus preventing isomerization. Structures and energetics of all four DNA nucleobase cation radicals are compared and discussed.
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Affiliation(s)
- Shu R Huang
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - Andy Dang
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - František Tureček
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
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14
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Dang A, Liu Y, Tureček F. UV–Vis Action Spectroscopy of Guanine, 9-Methylguanine, and Guanosine Cation Radicals in the Gas Phase. J Phys Chem A 2019; 123:3272-3284. [DOI: 10.1021/acs.jpca.9b01542] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Andy Dang
- Department of Chemistry, University of Washington, Bagley Hall,
Box 351700, Seattle, Washington 98195-1700, United States
| | - Yue Liu
- Department of Chemistry, University of Washington, Bagley Hall,
Box 351700, Seattle, Washington 98195-1700, United States
| | - František Tureček
- Department of Chemistry, University of Washington, Bagley Hall,
Box 351700, Seattle, Washington 98195-1700, United States
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15
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Liu Y, Korn JA, Dang A, Tureček F. Hydrogen-Rich Cation Radicals of DNA Dinucleotides: Generation and Structure Elucidation by UV-Vis Action Spectroscopy. J Phys Chem B 2018; 122:9665-9680. [PMID: 30269486 DOI: 10.1021/acs.jpcb.8b07925] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hydrogen-rich DNA dinucleotide cation radicals (dGG + 2H)+•, (dCG + 2H)+•, and (dGC + 2H)+• represent transient species comprising protonated and hydrogen atom adducted nucleobase rings that serve as models for proton and radical migrations in ionized DNA. These DNA cation radicals were generated in the gas phase by electron-transfer dissociation of dinucleotide dication-crown-ether complexes and characterized by UV-vis photodissociation action spectra, ab initio calculations of structures and relative energies, and time-dependent density functional theory calculations of UV-vis absorption spectra. Theoretical calculations indicate that (dGG + 2H)+• cation radicals formed by electron transfer underwent an exothermic conformational collapse that was accompanied by guanine ring stacking and facile internucleobase hydrogen atom transfer, forming 3'-guanine C-8-H radicals. In contrast, exothermic hydrogen transfer from the 5'-cytosine radical onto the guanine ring in (dCG + 2H)+• was kinetically hampered, resulting in the formation of a mixture of 5'-cytosine and 3'-guanine radicals. Conformational folding and nucleobase stacking were energetically unfavorable in (dGC + 2H)+• that retained its structure of a 3'-cytosine radical, as formed by one-electron reduction of the dication. Hydrogen-rich guanine (G + H)• and cytosine (C + H)• radicals were calculated to have vastly different basicities in water, as illustrated by the respective p Ka values of 20.0 and 4.6, which is pertinent to their different abilities to undergo proton-transfer reactions in solution.
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Affiliation(s)
- Yang Liu
- Department of Chemistry, Bagley Hall , University of Washington , P.O. Box 351700, Seattle , Washington 98195-1700 , United States
| | - Joseph A Korn
- Department of Chemistry, Bagley Hall , University of Washington , P.O. Box 351700, Seattle , Washington 98195-1700 , United States
| | - Andy Dang
- Department of Chemistry, Bagley Hall , University of Washington , P.O. Box 351700, Seattle , Washington 98195-1700 , United States
| | - František Tureček
- Department of Chemistry, Bagley Hall , University of Washington , P.O. Box 351700, Seattle , Washington 98195-1700 , United States
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16
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Sun Y, Zhou W, Moe MM, Liu J. Reactions of water with radical cations of guanine, 9-methylguanine, 2′-deoxyguanosine and guanosine: keto–enol isomerization, C8-hydroxylation, and effects of N9-substitution. Phys Chem Chem Phys 2018; 20:27510-27522. [DOI: 10.1039/c8cp05453c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactions of D2O with guanine radical cations in nucleobases and nucleosides were studied in the gas phase using the guided-ion-beam experiment and computational modeling.
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Affiliation(s)
- Yan Sun
- Department of Chemistry and Biochemistry
- Queens College of the City University of New York
- Queens
- USA
- PhD Program in Chemistry
| | - Wenjing Zhou
- Department of Chemistry and Biochemistry
- Queens College of the City University of New York
- Queens
- USA
| | - May Myat Moe
- Department of Chemistry and Biochemistry
- Queens College of the City University of New York
- Queens
- USA
| | - Jianbo Liu
- Department of Chemistry and Biochemistry
- Queens College of the City University of New York
- Queens
- USA
- PhD Program in Chemistry
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17
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Dang A, Nguyen HTH, Ruiz H, Piacentino E, Ryzhov V, Tureček F. Experimental Evidence for Noncanonical Thymine Cation Radicals in the Gas Phase. J Phys Chem B 2017; 122:86-97. [DOI: 10.1021/acs.jpcb.7b09872] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Andy Dang
- Department
of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - Huong T. H. Nguyen
- Department
of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - Heather Ruiz
- Department
of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - Elettra Piacentino
- Department
of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - Victor Ryzhov
- Department
of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - František Tureček
- Department
of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
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18
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Lesslie M, Lawler JT, Dang A, Korn JA, Bím D, Steinmetz V, Maître P, Tureček F, Ryzhov V. Cytosine Radical Cations: A Gas‐Phase Study Combining IRMPD Spectroscopy, UVPD Spectroscopy, Ion–Molecule Reactions, and Theoretical Calculations. Chemphyschem 2017; 18:1293-1301. [DOI: 10.1002/cphc.201700281] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Michael Lesslie
- Department of Chemistry and Biochemistry Northern Illinois University DeKalb IL 60115 USA
| | - John T. Lawler
- Department of Chemistry and Biochemistry Northern Illinois University DeKalb IL 60115 USA
| | - Andy Dang
- Department of Chemistry University of Washington Bagley Hall, Box 351700 Seattle Washington 98195 USA
| | - Joseph A. Korn
- Department of Chemistry University of Washington Bagley Hall, Box 351700 Seattle Washington 98195 USA
| | - Daniel Bím
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic 166 10 Prague 6 Czech Republic
| | - Vincent Steinmetz
- Laboratoire de Chimie Physique Université Paris-Sud UMR8000 CNRS 91405 Orsay France
| | - Philippe Maître
- Laboratoire de Chimie Physique Université Paris-Sud UMR8000 CNRS 91405 Orsay France
| | - Frantisek Tureček
- Department of Chemistry University of Washington Bagley Hall, Box 351700 Seattle Washington 98195 USA
| | - Victor Ryzhov
- Department of Chemistry and Biochemistry Northern Illinois University DeKalb IL 60115 USA
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19
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Zhang S, Liu H, Cheng P, Ren D, Gong X. Analysis of the [CuL n ]2+ and [CuG n ]2+ (n = 2–4) complex structures: Comparison with CID experiment and DFT calculation. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2016. [DOI: 10.1134/s0036024416130173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Poully JC, Miles J, De Camillis S, Cassimi A, Greenwood JB. Proton irradiation of DNA nucleosides in the gas phase. Phys Chem Chem Phys 2015; 17:7172-80. [DOI: 10.1039/c4cp05303f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Charge localization within nucleosides after proton irradiation is strongly influenced by the ionization energy of the base.
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Affiliation(s)
| | - Jordan Miles
- Centre for Plasma Physics
- School of Mathematics and Physics
- Queen's University Belfast
- Northern Ireland
- UK
| | - Simone De Camillis
- Centre for Plasma Physics
- School of Mathematics and Physics
- Queen's University Belfast
- Northern Ireland
- UK
| | - Amine Cassimi
- CIMAP (UMR 6252 CEA, Université de Caen, ENSICAEN, CNRS)
- 14070 CAEN Cedex 5
- France
| | - Jason B. Greenwood
- Centre for Plasma Physics
- School of Mathematics and Physics
- Queen's University Belfast
- Northern Ireland
- UK
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21
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Feketeová L, Chan B, Khairallah GN, Steinmetz V, Maître P, Radom L, O'Hair RAJ. Gas-phase structure and reactivity of the keto tautomer of the deoxyguanosine radical cation. Phys Chem Chem Phys 2015; 17:25837-44. [DOI: 10.1039/c5cp01573a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gas-phase IR spectroscopy, ion–molecule reactions, collision-induced dissociation and computational chemistry in combination form a powerful tool to gain insights into the structure of one-electron oxidised guanine in DNA and its resultant chemistry.
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Affiliation(s)
- Linda Feketeová
- School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology
- The University of Melbourne
- Parkville
- Australia
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology
| | - Bun Chan
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology
- Australia
- School of Chemistry
- University of Sydney
- Australia
| | - George N. Khairallah
- School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology
- The University of Melbourne
- Parkville
- Australia
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology
| | | | - Philippe Maître
- Laboratoire de Chimie Physique
- Université Paris Sud
- Orsay Cedex
- France
| | - Leo Radom
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology
- Australia
- School of Chemistry
- University of Sydney
- Australia
| | - Richard A. J. O'Hair
- School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology
- The University of Melbourne
- Parkville
- Australia
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology
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22
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Ostrowski W, Dzikowska A, Frański R. Formation of curcumin molecular ion under electrospray ionisation conditions in the presence of metal cations. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2014; 20:163-168. [PMID: 24895776 DOI: 10.1255/ejms.1251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Electrospray ionisation (ESI) mass spectra obtained for solutions containing curcumin, copper cation and other metal cations, namely Co2+, Ni2+, Mn2+ and Zn2+, have shown an abundant curcumin molecular ion at m/z 368. This ion was not formed for solutions containing curcumin and copper cations or for those containing curcumin and other metal cations. To the best of our knowledge, it is the first example of a system in which copper cations and other metal cations promote formation of organic radical cation under ESI conditions.
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23
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Ostrowski W, Karczewska K, Frański R. Oxidation of paracetamol by Cu2+--formation of the paracetamol radical cation. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:1579-1584. [PMID: 23722693 DOI: 10.1002/rcm.6583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 03/25/2013] [Accepted: 03/28/2013] [Indexed: 06/02/2023]
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24
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Ostrowski W, Linko K, Frański R. Formation of diclofenac molecular ions as the effect of Cu(2+)-π interaction under electrospray ionization mass spectrometry conditions. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2012; 18:43-50. [PMID: 22792613 DOI: 10.1255/ejms.1166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Solutions containing diclofenac (M) and a copper salt [CuCl2, Cu(ClO4)2, Cu(NO3)2, CuSO4) were analysed by electrospray ionisation mass spectrometry (ESI-MS). Because of the cation-pi interactions in diclofenac-Cu(II) complexes, the diclofenac molecular ion M+* at m/z 295 was formed. It was found that the solvent composition (methanol versus water/methanol) and counter ion strongly affect the M+* ion formation. Formation pathways of ion M+* are discussed.
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Affiliation(s)
- Wojciech Ostrowski
- Adam Mickiewicz University, Faculty of Chemistry, Grunwaldzka 6, 60-780 Poznań, Poland
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25
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Zhang S, Xu L, Dong J, Cheng P, Zhou Z, Fu J. Collision-induced dissociation of singly and doubly charged CuII–cytidine complexes in the gas phase: an experimental and computational study. RSC Adv 2012. [DOI: 10.1039/c2ra01293f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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26
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Ke Y, El Aribi H, Siu CK, Siu KWM, Hopkinson AC. A comparison of the fragmentation pathways of [Cu(II)(Ma)(Mb)]•2+ complexes where Ma and Mb are peptides containing either a tryptophan or a tyrosine residue. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:3485-3492. [PMID: 21072806 DOI: 10.1002/rcm.4783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
[Cu(II)(M(a))(M(b))](•2+) complexes, where M(a) and M(b) are dipeptides or tripeptides each containing either a tryptophan (W) or tyrosine (Y) residue, have been examined by means of electrospray tandem mass spectrometry. Collision-induced dissociations (CIDs) of complexes containing identical peptides having a tryptophan residue generated abundant radical cations of the peptides; by contrast, for complexes containing peptides having a tyrosine residue, the main fragmentation channel is dissociative proton transfer to give [M(a) + H](+) and [Cu(II)(M(b)-H)](•+). When there are two different peptides in the complex, each containing a tryptophan residue, radical cations are again the major products, with their relative abundances depending on the locations of the tryptophan residue in the peptides. In the CIDs of mixed complexes, where one peptide contains a tryptophan residue and the other a tyrosine residue, the main fragmentation channel is formation of the radical cation of the tryptophan-containing peptide and not proton transfer from the tyrosine-containing peptide to give a protonated peptide.
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Affiliation(s)
- Yuyong Ke
- Department of Chemistry and Centre for Research in Mass Spectrometry, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
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27
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Cheng P, Li Y, Li S, Zhang M, Zhou Z. Collision-induced dissociation (CID) of guanine radical cation in the gas phase: an experimental and computational study. Phys Chem Chem Phys 2010; 12:4667-77. [DOI: 10.1039/b919513k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Feketeová L, Ryzhov V, O'Hair RAJ. Comparison of collision- versus electron-induced dissociation of Pt(II) ternary complexes of histidine- and methionine-containing peptides. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:3133-3143. [PMID: 19714712 DOI: 10.1002/rcm.4234] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Incubation of the histidine-containing peptides (GH, HG, GGH, GHG, HGG) and methionine-containing peptides (GM, MG, GGM, GMG, MGG) with the platinum complexes [Pt(terpy)Cl](+) (A) and [Pt(dien)Cl](+) (B) followed by electrospray ionisation (ESI) led to a number of singly and doubly charged ternary platinum peptide complexes, including [Pt(L)M](2+) and [Pt(L)M-H](+) (where L = the ligand terpy or dien; M is a peptide). Each of the [Pt(L)M](2+) complexes was subjected to electron capture dissociation (ECD), collision-induced dissociation (CID) and electron-induced dissociation (EID), while each of the [Pt(L)M-H](+) complexes was subjected to CID and EID. Results from ECD suggest that the free electron is captured by the metal ion thus weakening the bonds to its ligands. In the case of the ligand terpy, which binds more strongly than dien, this weakening leads to the loss of the peptide. The minor products in the ECD spectra of [Pt(terpy)M](2+) complexes do show fragmentation along the peptide backbone, but the ions observed are of the a-, b-, and y-type. For the complexes with methionine-containing peptides, a marker ion, [Pt(L)SCH(3)](+), was found which is indicative of binding of Pt to the methionine side chain. For the histidine-containing peptides, an ion containing platinum, the auxiliary ligand, and the histidine imine was observed in many instances, thus indicating the binding of the histidine side chain to the metal, but other modes of Pt coordination (N-terminus) were also found to be competitive. These findings are consistent with a recent finding (Sze et al. J. Biol. Inorg. Chem. 2009; 14: 163) that Pt occupies the methionine-rich copper(I)-binding site rather than histidine-rich copper(II)-binding site in the CopC protein.
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Affiliation(s)
- Linda Feketeová
- School of Chemistry, University of Melbourne, Victoria 3010, Australia
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29
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Cummings SD. Platinum complexes of terpyridine: Interaction and reactivity with biomolecules. Coord Chem Rev 2009. [DOI: 10.1016/j.ccr.2008.12.009] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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30
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Frański R, Gierczyk B, Schroeder G. Anion-pi interactions-interactions between benzo-crown ether metal cation complexes and counter ions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2009; 20:257-262. [PMID: 18990586 DOI: 10.1016/j.jasms.2008.09.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 09/23/2008] [Accepted: 09/29/2008] [Indexed: 05/27/2023]
Abstract
The loss of X(.) radical from [M + Cu + X](+) ions (copper reduction) has been studied by the so called in-source fragmentation at higher cone voltage (M = crown ether molecule, X(-) = counter ion, ClO(4)(-), NO(3)(-), Cl(-)). The loss of X(.) has been found to be affected by the presence/lack of aromatic ring poor/rich in electrons. Namely, the loss of X(.) occurs with lower efficiency for the [NO(2)-B15C5 + Cu + X](+) ions than for the [B15C5 + Cu + X](+) ions, where NO(2)-B15C5 = 3-nitro-benzo-15-crown-5, B15C5 = benzo-15-crown-5. A reasonable explanation is that Anion-pi interactions prevent the loss of X(.) from the [NO(2)-B15C5 + Cu + X](+) ions. The presence of the electron-withdrawing NO(2) group causes the aromatic ring to be poor in electrons and thus its enhances its interactions with anions. For the ion containing the aromatic ring enriched in electrons, namely [NH(2)-B15C5 + Cu + ClO(4)](+) where NH(2)-B15C5 = 3-amino-benzo-15-crown-5, the opposite situation has been observed. Because of Anion-pi repulsion the loss of X(.) radical proceeds more readily for [NH(2)-B15C5 + Cu + X](+) than for [B15C5 + Cu + X](+). Iron reduction has also been found to be affected by Anion-pi interactions. Namely, the loss of CH(3)O(.) radical from the ion [B15C5 + Fe + NO(3) + CH(3)O](+) proceeds more readily than from [NO(2)(-)B15C5 + Fe + NO(3) + CH(3)O](+).
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Affiliation(s)
- Rafał Frański
- Faculty of Chemistry, Adam Mickiewicz University, Poznań, Poland.
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31
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Khairallah GN, Stewart MB, Yuriev E, Xu Y, Orbell JD, O'Hair RAJ. Gas phase supramolecular cluster ions of deoxyguanosine induced by binding to (2,2′:6′2″-terpyridine)-platinum(II) and (diethylenetriamine)-platinum(II). Dalton Trans 2009:1542-8. [DOI: 10.1039/b815094j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Frański R, Gierczyk B. Formation of organometallic species, [M - H](+) ions and radical cations upon mass spectrometric fragmentation of mercury-crown ether complexes. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2009; 15:479-486. [PMID: 19661556 DOI: 10.1255/ejms.1005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Mass spectrometric fragmentation pathways of [M + HgClO(4)](+) (M - crown ether molecule), determined by tandem mass spectrometry experiments, are discussed in detail. The decomposition of [M + HgClO(4)](+) proceeds along three fragmentation pathways: formation of [M - H](+) ions, formation of organometallic species, namely [M - H + Hg](+) ions, and formation of radical cations [M](+*). The factors influencing these processes, namely crown ether cavities and the presence of electron withdrawing/electron donor groups, have been discussed.
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Affiliation(s)
- Rafał Frański
- Faculty of Chemistry, Adam Mickiewicz University, Grunwałdzka 6, 60-780, Poznań, Poland.
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33
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Schäfer M, Drayß M, Springer A, Zacharias P, Meerholz K. Radical Cations in Electrospray Mass Spectrometry: Formation of Open‐Shell Species, Examination of the Fragmentation Behaviour in ESI‐MS
n
and Reaction Mechanism Studies by Detection of Transient Radical Cations. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700199] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Mathias Schäfer
- Institute for Organic Chemistry, University of Cologne, Greinstrasse 4, 50939 Köln, Germany, Fax: +49‐221‐4703064
| | - Miriam Drayß
- Institute for Organic Chemistry, University of Cologne, Greinstrasse 4, 50939 Köln, Germany, Fax: +49‐221‐4703064
| | - Andreas Springer
- Department of Chemistry, Free University Berlin, Berlin, Germany
| | - Philipp Zacharias
- Institute of Physical Chemistry, University of Cologne, Köln, Germany
| | - Klaus Meerholz
- Institute of Physical Chemistry, University of Cologne, Köln, Germany
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Mitkina T, Fedin V, Llusar R, Sorribes I, Vicent C. Distinctive unimolecular gas-phase reactivity of [M(en)2]2+ (M = Ni, Cu) dications and their inclusion complexes with the macrocyclic cavitand cucurbit[8]uril. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:1863-72. [PMID: 17716910 DOI: 10.1016/j.jasms.2007.07.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 07/19/2007] [Accepted: 07/19/2007] [Indexed: 05/16/2023]
Abstract
Electrospray ionization mass spectrometry makes it possible to generate gas-phase bis-ethylenediamine nickel and copper dications, [M(en)(2)](2+) (M = Ni, 1; M = Cu, 2), as well as their {[M(en)(2)]@cuc[8]}(2+) inclusion complexes with the macrocyclic cavitand cucurbit[8]uril (cuc[8]). The unimolecular gas-phase reactivity of these species has been investigated by electrospray ionization tandem mass spectrometry with a quadrupole-time-of-flight configuration. Distinctive fragmentation pathways have been observed for the free and encapsulated [M(en)(2)](2+) (M = Ni, Cu) dications under collision-induced dissociation (CID) conditions. The dications [M(en)(2)](2+) (M = Ni, Cu) dissociate according to several competitive pathways that involve intra-complex hydrogen or electron-transfer processes. Most of these channels are suppressed after encapsulation inside the cucurbit[8]uril macrocycle and, as a consequence, a simplification of the {[M(en)(2)]@cuc[8]}(2+) fragmentation pattern is observed. The results obtained demonstrate that the encapsulation of a coordination complex inside a host molecule can be used to alter the nature of the product ions generated under CID conditions.
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Affiliation(s)
- Tatyana Mitkina
- A. V. Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russian Federation
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Cheng P, Bohme DK. Gas-Phase Formation of Radical Cations of Monomers and Dimers of Guanosine by Collision-Induced Dissociation of Cu(II)−Guanosine Complexes. J Phys Chem B 2007; 111:11075-82. [PMID: 17715957 DOI: 10.1021/jp071933l] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An electrosprayed water/methanol solution of guanosine and Cu(NO3)2 was observed to give rise to gas-phase copper complexed ions of [CuLn]*2+, [CuL(MeOH)n]*2+, and [CuG n(NO3)]*+, as well as the ions [L]*+, [L+H]+, [G]*+, and [G+H]+ (L=guanosine, G=guanine). The Collision-Induced Dissociation (CID) of [CuL3]*2+ and [CuL(MeOH)n]*2+ (n=2, 3) generates guanosine radical cations [L]*+, while dimeric guanosine radical cations [L2]*+ are generated in the dissociation of [CuL4]*2+. Protonated guanosine [L+H]+ is one of the main products in the primary dissociation of [CuL2]*2+, while the dissociation of the higher-order [CuG2]*2+ produces the [G]*+ radical cation. The guanosine dimer radical cation, [L2]*+ presumably arises from the interaction of two guanosine molecules via proton and hydrogen bonding and is observed to dissociate into [L+H]+ and [L-H]* at low energies. We propose that the first two ligands bind strongly with Cu(II) through N7 and O6 to form a [CuL2]*2+ complex with a four-coordinated planar structure and that a third ligand binds loosely with copper to form [CuL3]*2+. Additional ligation observed in the formation of [CuLn]*2+ (n<or=6) ions is presumed to occur by hydrogen bonding. The ribose group of guanosine appears to play an important role in the stabilization of the doubly charged Cu-guanosine complex and in intraligand proton transfer upon CID. The molecular radical cations [L]*+ observed in the ESI-MS spectrum at low declustering potentials originate primarily from [CuL(MeOH)2,3]*2+ complexes which can dissociate more easily than [CuL3]*2+.
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Affiliation(s)
- Ping Cheng
- Department of Chemistry, Centre for Research in Mass Spectrometry and Centre for Research in Earth and Space Science, York University, Toronto, Ontario, Canada, M3J 1P3
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Turecek F. Copper-biomolecule complexes in the gas phase. The ternary way. MASS SPECTROMETRY REVIEWS 2007; 26:563-82. [PMID: 17474124 DOI: 10.1002/mas.20137] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
This review deals with copper complexes of a variety of organic and bioorganic molecules that have been produced as gas-phase ions by electrospray and other ionization methods and studied experimentally by mass spectrometry and theoretically by ab initio and density functional theory computations. Ternary complexes of Cu((II)) allow one to modify the oxidation state and coordination sphere of the copper ion and thus induce novel fragmentations that involve redox and radical-based reactions. Structure elucidation, distinction, and quantitation of leucine and isoleucine isomers in peptides, distinction of enantiomers in chiral compounds, and sensitive detection of antibiotics are some of the highlights of mass spectrometry of ternary copper complexes. Binary copper complexes are mainly represented by Cu((I)) species in which the copper ion displays the properties of a weak Lewis acid.
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Affiliation(s)
- Frantisek Turecek
- Department of Chemistry, Bagley Hall, University of Washington, Seattle, WA 98195-1700, USA.
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Lam AKY, Abrahams BF, Grannas MJ, McFadyen WD, O'Hair RAJ. Tuning the gas phase redox properties of copper(ii) ternary complexes of terpyridines to control the formation of nucleobase radical cations. Dalton Trans 2006:5051-61. [PMID: 17060991 DOI: 10.1039/b609688c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrospray ionization (ESI) tandem mass spectrometry (MS/MS) of ternary copper(II) complexes of [Cu(terpyX)(M)]2+ (where terpyX = is a substituted 2,2':6',2''-terpyridine ligand; M = the nucleobases: adenine, guanine, thymine and cytosine) was examined as a means of forming radical cations of nucleobases in the gas phase. The following substituents were examined: 4'-NMe2-2,2':6',6''-terpyridine; 4'-OH-2,2':6',6''-terpyridine; 4'-F-2,2':6',6''-terpyridine; 2,2':6',6''-terpyridine; 4'-Cl-2,2':6',6''-terpyridine; 4'-Br-2,2':6',6''-terpyridine; 4'-CO2H-2,2':6',6''-terpyridine; 4'-NO2-2,2':6',6''-terpyridine and 6,6''-dibromo-2',2:6',2''-terpyridine. Each of the ternary complexes [Cu(terpyX)(M)]2+ was mass selected and subjected to collision induced dissociation (CID) in a quadrupole ion trap. The types of fragmentation reactions observed for these complexes depend on the nature of the substituent on the terpyridine ligand, while the yields of the radical cations of the nucleobases follow the order of their ionization energies (IEs): G (lowest IE) > A > C > T (highest IE). In general, radical cation formation is favoured for electron withdrawing substituents (e.g. NO2) while loss of the neutral nucleobase is favoured for electron donating substituents (e.g. NMe2). Loss of the protonated nucleobase is a major fragmentation pathway for the OH substituted terpyridine system, consistent with its ability to bind to a metal centre as a deprotonated ligand. Crystal structure determinations of (6,6''-dibromo-2',2:6',2''-terpyridine)bis(nitrato)copper(II) and diaqua(4'-oxo-2,2':6',6''-terpyridine)copper(II) nitrate monohydrate were performed and correlated with the ESI results.
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Affiliation(s)
- Adrian K Y Lam
- School of Chemistry, University of Melbourne, Victoria, 3010, Australia
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O'Hair RAJ. The 3D quadrupole ion trap mass spectrometer as a complete chemical laboratory for fundamental gas-phase studies of metal mediated chemistry. Chem Commun (Camb) 2006:1469-81. [PMID: 16575433 DOI: 10.1039/b516348j] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Electrospray ionization provides a "treasure trove" of metal containing ions whose fundamental reactivity can be studied via collision induced dissociation and ion-molecule reactions using the multistage mass spectrometry capabilities of the quadrupole ion trap mass spectrometer. Examples of metal mediated chemistry relevant to catalysis, C-C bond coupling, bioinorganic and supramolecular chemistry are highlighted.
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Affiliation(s)
- Richard A J O'Hair
- School of Chemistry, University of Melbourne, Melbourne, Victoria 3010, Australia.
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