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Zima V, Gladwish O, Marek A, Tureček F. Nucleoside Cation Radicals: Generation, Radical-Induced Hydrogen Atom Migrations, and Ribose Ring Cleavage in the Gas Phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:1594-1608. [PMID: 38842116 DOI: 10.1021/jasms.4c00198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
Nucleoside ions that were furnished on ribose with a 2'-O-acetyl radical group were generated in the gas phase by multistep collision-induced dissociation of precursor ions tagged with radical initiator groups, and their chemistry was investigated in the gas phase. 2'-O-Acetyladenosine cation radicals were found to undergo hydrogen transfer to the acetoxyl radical from the ribose ring positions that were elucidated using specific deuterium labeling of 1'-H, 2'-H, and 4'-H and in the N-H and O-H exchangeable positions, favoring 4'-H transfer. Ion structures and transition-state energies were calculated by a combination of Born-Oppenheimer molecular dynamics and density functional theory and used to obtain unimolecular rate constants for competitive hydrogen transfer and loss of the acetoxyl radical. Migrations to the acetoxyl radical of ribose hydrogens 1'-H, 2'-H, 3'-H, and 4'-H were all exothermic, but product formation was kinetically controlled. Both Rice-Ramsperger-Kassel-Marcus (RRKM) and transition-state theory (TST) calculations indicated preferential migration of 4'-H in a qualitative agreement with the deuterium labeling results. The hydrogen migrations displayed substantial isotope effects that along with quantum tunneling affected the relative rate constants and reaction branching ratios. UV-vis action spectroscopy indicated that the cation radicals from 2'-O-acetyladenosine consisted of a mixture of isomers. Radical-driven dissociations were also observed for protonated guanosine, cytosine, and thymidine conjugates. However, for those nucleoside ions and cation radicals, the dissociations were dominated by the loss of the nucleobase or formation of protonated nucleobase ions.
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Affiliation(s)
- Václav Zima
- Department of Chemistry, University of Washington, 351700 Bagley Hall, Seattle, Washington 98195-1700, United States
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 166 10 Prague, Czech Republic
| | - Owen Gladwish
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078, United States
| | - Aleš Marek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 166 10 Prague, Czech Republic
| | - František Tureček
- Department of Chemistry, University of Washington, 351700 Bagley Hall, Seattle, Washington 98195-1700, United States
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2
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Molina FL, Broquier M, Soorkia S, Grégoire G, Pino GA. Selective Tautomer Production and Cryogenic Ion Spectroscopy of Radical Cations: The Uracil and Thymine Cases. J Phys Chem A 2024. [PMID: 38656804 DOI: 10.1021/acs.jpca.4c02199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The vibrational and electronic spectroscopy of the radical cations of two nucleobases (NB) (uracil and thymine) was studied by cryogenic ion photodissociation spectroscopy. The radical cations have been generated from the photodissociation of NB-Ag+ complexes. A charge transfer process from the NB to Ag+ governs the deactivation mechanism, leading to the formation of the radical cation without further tautomerization. Single- and double-resonance spectroscopy allows for structural assignments of both the silver complexes and the radical cations by comparison with DFT-based calculations. Interestingly, a tautomer-dependent fragmentation is observed in the thymine enol form that involves the loss of NCO, a fragment which was never reported before for this NB. This selective photodissociation of silver complexes containing aromatic chromophore greatly expands the current technique to produce isomer-selected radical cations in the gas phase providing benchmark experimental data to assess calculations of open-shell species.
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Affiliation(s)
- Franco L Molina
- Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba. Haya de la Torre y Medina Allende. Pabellón Argentina, Ciudad Universitaria, Córdoba X5000HUA, Argentina
- INFIQC: Instituto de Investigaciones en Físico-Química de Córdoba (CONICET-UNC). Haya de la Torre y Medina Allende. Pabellón Argentina, Ciudad Universitaria, Córdoba X5000HUA, Argentina
- Departamento de Fisicoquímica, Fac. de Ciencias Químicas, Universidad Nacional de Córdoba. Haya de la Torre y Medina Allende. Pabellón Argentina, Ciudad Universitaria, Córdoba X5000HUA, Argentina
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, Orsay F-91405, France
| | - Michel Broquier
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, Orsay F-91405, France
| | - Satchin Soorkia
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, Orsay F-91405, France
| | - Gilles Grégoire
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, Orsay F-91405, France
| | - Gustavo A Pino
- Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba. Haya de la Torre y Medina Allende. Pabellón Argentina, Ciudad Universitaria, Córdoba X5000HUA, Argentina
- INFIQC: Instituto de Investigaciones en Físico-Química de Córdoba (CONICET-UNC). Haya de la Torre y Medina Allende. Pabellón Argentina, Ciudad Universitaria, Córdoba X5000HUA, Argentina
- Departamento de Fisicoquímica, Fac. de Ciencias Químicas, Universidad Nacional de Córdoba. Haya de la Torre y Medina Allende. Pabellón Argentina, Ciudad Universitaria, Córdoba X5000HUA, Argentina
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3
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Zima V, Marek A, Tureček F. Competitive Radical Migrations and Ribose Ring Cleavage in Adenosine and 2'-Deoxyadenosine Cation Radicals. J Phys Chem A 2024; 128:1109-1123. [PMID: 38316031 DOI: 10.1021/acs.jpca.3c07906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
We report a combined experimental and computational study of adenosine cation radicals that were protonated at adenine and furnished with a radical handle in the form of an acetoxyl radical, •CH2COO, that was attached to ribose 5'-O. Radicals were generated by collision-induced dissociation (CID) and characterized by tandem mass spectrometry and UV-vis photodissociation action spectroscopy. The acetoxyl radical was used to probe the kinetics of intramolecular hydrogen transfer from the ribose ring positions that were specifically labeled with deuterium at C1', C2', C3', C4', C5', and in the exchangeable hydroxyl groups. Hydrogen transfer was found to chiefly involve 3'-H with minor contributions by 5'-H and 2'-H, while 4'-H was nonreactive. The hydrogen transfer rates were affected by deuterium isotope effects. Hydrogen transfer triggered ribose ring cleavage by consecutive dissociations of the C4'-O and C1'-C2' bonds, resulting in expulsion of a C6H9O4 radical and forming a 9-formyladenine ion. Rice-Ramsperger-Kassel-Marcus (RRKM) and transition-state theory (TST) calculations of unimolecular constants were carried out using the effective CCSD(T)/6-311++G(3d,2p) and M06-2X/aug-cc-pVTZ potential energy surfaces for major isomerizations and dissociations. The kinetic analysis showed that hydrogen transfer to the acetoxyl radical was the rate-determining step, whereas the following ring-opening reactions in ribose radicals were fast. Using DFT-computed energies, a comparison was made between the thermochemistry of radical reactions in adenosine and 2'-deoxyadenosine cation radicals. The 2'-deoxyribose ring showed lower TS energies for both the rate-determining 3'-H transfer and ring cleavage reactions.
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Affiliation(s)
- Václav Zima
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 166 10 Prague 6, Czech Republic
| | - Aleš Marek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 166 10 Prague 6, Czech Republic
| | - František Tureček
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
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Raczyńska ED. On Prototropy and Bond Length Alternation in Neutral and Ionized Pyrimidine Bases and Their Model Azines in Vacuo. Molecules 2023; 28:7282. [PMID: 37959699 PMCID: PMC10648772 DOI: 10.3390/molecules28217282] [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: 09/25/2023] [Revised: 10/21/2023] [Accepted: 10/22/2023] [Indexed: 11/15/2023] Open
Abstract
In this review, the complete tautomeric equilibria are derived for disubstituted pyrimidine nucleic acid bases starting from phenol, aniline, and their model compounds-monosubstituted aromatic azines. The differences in tautomeric preferences for isolated (gaseous) neutral pyrimidine bases and their model compounds are discussed in light of different functional groups, their positions within the six-membered ring, electronic effects, and intramolecular interactions. For the discussion of tautomeric preferences and for the analysis of internal effects, recent quantum-chemical results are taken into account and compared to some experimental ones. For each possible tautomer-rotamer of the title compounds, the bond length alternation, measured by means of the harmonic oscillator model of electron delocalization (HOMED) index, is examined. Significant HOMED similarities exist for mono- and disubstituted derivatives. The lack of parallelism between the geometric (HOMED) and energetic (ΔG) parameters for all possible isomers clearly shows that aromaticity is not the main factor that dictates tautomeric preferences for pyrimidine bases, particularly for uracil and thymine. The effects of one-electron loss (positive ionization) and one-electron gain (negative ionization) on prototropy and bond length alternation are also reviewed for pyrimidine bases and their models.
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Affiliation(s)
- Ewa Daniela Raczyńska
- Department of Chemistry, Warsaw University of Life Sciences (SGGW), ul. Nowoursynowska 159c, 02-776 Warszawa, Poland
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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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Finazzi L, Martens J, Berden G, Oomens J. Probing radical versus proton migration in the aniline cation with IRMPD spectroscopy. Mol Phys 2023. [DOI: 10.1080/00268976.2023.2192307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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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: 2.0] [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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8
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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: 8] [Impact Index Per Article: 4.0] [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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9
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Brož B, Tureček F, Marek A. Low scale syringe-made synthesis of 15 N-labelled oligonucleotides. J Labelled Comp Radiopharm 2022; 65:309-314. [PMID: 36002916 DOI: 10.1002/jlcr.4000] [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: 07/11/2022] [Revised: 08/18/2022] [Accepted: 08/23/2022] [Indexed: 11/09/2022]
Abstract
Fast and reasonable low-scale (200 nmol) syringe-made synthesis of 15 N-labelled oligonucleotides representing DNA trinucleotide codons is communicated. All codons were prepared by solid-phase controlled pore glass synthesis column technique via the phosphoramidite method. Twenty-four labelled oligonucleotides covering the DNA genetic code alphabet were prepared using commercially available reagents and affordable equipment in a reasonably short period of time, with acceptable yields and purity for direct applications in mass spectrometry.
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Affiliation(s)
- Břetislav Brož
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague
| | | | - Aleš Marek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague
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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: 1.7] [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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Huang SR, Tureček F. Noncanonical Isomers of Nucleoside Cation Radicals: An Ab Initio Study of the Dark Matter of DNA Ionization. J Phys Chem A 2022; 126:2480-2497. [PMID: 35439003 DOI: 10.1021/acs.jpca.2c00894] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cation radicals of DNA nucleosides, 2'-deoxyadenosine, 2'-deoxyguanosine, 2'-deoxycytidine, and 2'-deoxythymidine, can exist in standard canonical forms or as noncanonical isomers in which the charge is introduced by protonation of the nucleobase, whereas the radical predominantly resides in the deoxyribose moiety. Density functional theory as well as correlated ab initio calculations with coupled clusters (CCSD(T)) that were extrapolated to the complete basis set limit showed that noncanonical nucleoside ion isomers were thermodynamically more stable than their canonical forms in both the gas phase and as water-solvated ions. This indicated the possibility of exothermic conversion of canonical to noncanonical forms. The noncanonical isomers were calculated to have very low adiabatic ion-electron recombination energies (REad) for the lowest-energy isomers 2'-deoxy-(N-3H)adenos-1'-yl (4.74 eV), 2'-deoxy-(N-7H)guanos-1'-yl (4.66 eV), 2'-deoxy-(N-3H)cytid-1'-yl (5.12 eV), and 2'-deoxy-5-methylene-(O-2H)uridine (5.24 eV). These were substantially lower than the REad value calculated for the canonical 2'-deoxyadenosine, 2'-deoxy guanosine, 2'-deoxy cytidine, and 2'-deoxy thymidine cation radicals, which were 7.82, 7.46, 8.14, and 8.20 eV, respectively, for the lowest-energy ion conformers of each type. Charge and spin distributions in noncovalent cation-radical dA⊂dT and dG⊂dC nucleoside pairs and dAT, dCT, dTC, and dGC dinucleotides were analyzed to elucidate the electronic structure of the cation radicals. Born-Oppenheimer molecular dynamics trajectory calculations of the dinucleotides and nucleoside pairs indicated rapid exothermic proton transfer from noncanonical T+· to A in both dAT+· and dA⊂dT+·, leading to charge and radical separation. Noncanonical T+· in dCT+· and dTC+· initiated rapid proton transfer to cytosine, whereas the canonical dCT+· dinucleotide ion retained the cation radical structure without isomerization. No spontaneous proton transfer was found in dGC+· and dG⊂dC+· containing canonical neutral and noncanonical ionized deoxycytidine.
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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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Molina F, Dezalay J, Soorkia S, Broquier M, Hochlaf M, Pino GA, Grégoire G. Cryogenic IR and UV spectroscopy of isomer-selected cytosine radical cation. Phys Chem Chem Phys 2022; 24:25182-25190. [DOI: 10.1039/d2cp03953b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
The UV photodissociation of cryogenic-cooled isomer-selected cytosine–silver complex leads to the production of cytosine radical cation without isomerization.
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Affiliation(s)
- Franco Molina
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, F-91405 Orsay, France
- INFIQC (CONICET-UNC), Ciudad Universitaria, Pabellón Argentina, 5000 Córdoba, Argentina
- Departamento de Fisicoquímica, Fac. de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Pabellón Argentina, X5000HUA Córdoba, Argentina
- Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Ciudad Universitaria, Pabellón Argentina, X5000HUA Córdoba, Argentina
| | - Jordan Dezalay
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, F-91405 Orsay, France
| | - Satchin Soorkia
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, F-91405 Orsay, France
| | - Michel Broquier
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, F-91405 Orsay, France
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes 77454, Champs sur Marne, France
| | - Gustavo Ariel Pino
- INFIQC (CONICET-UNC), Ciudad Universitaria, Pabellón Argentina, 5000 Córdoba, Argentina
- Departamento de Fisicoquímica, Fac. de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Pabellón Argentina, X5000HUA Córdoba, Argentina
| | - Gilles Grégoire
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, F-91405 Orsay, France
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Marlton SJP, Trevitt A. Laser Photodissocation, Action Spectroscopy and Mass Spectrometry Unite to Detect and Separate Isomers. Chem Commun (Camb) 2022; 58:9451-9467. [DOI: 10.1039/d2cc02101c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The separation and detection of isomers remains a challenge for many areas of mass spectrometry. This article highlights laser photodissociation and ion mobility strategies that have been deployed to tackle...
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14
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Zhou W, Liu J. Reaction mechanism and dynamics for C8-hydroxylation of 9-methylguanine radical cation by water molecules. Phys Chem Chem Phys 2021; 23:24464-24477. [PMID: 34698322 DOI: 10.1039/d1cp03884b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In contrast to their spontaneous deprotonation in aqueous solution, reactions of guanine and guanosine radical cations with water in the gas phase are exclusively initiated by hydration of the radical cations as reported in recent work (Y. Sun et al., Phys. Chem. Chem. Phys., 2018, 20, 27510). As gas-phase hydration reactions closely mimic the actual scenario for guanine radical cations in double-stranded DNA, exploration of subsequent reactions within their water complexes can provide an insight into the resulting oxidative damage to nucleosides. Herein guided-ion beam mass spectrometry experiment and direct dynamics trajectory simulations were carried out to examine prototype complexes of the 9-methylguanine radical cation with one and two water ligands (i.e., 9MG˙+·(H2O)1-2) in the gas phase, wherein the complexes were activated by collisional activation in the experiment and by thermal excitation at high temperatures in the simulations. Guided by mass spectroscopic measurements, trajectory results and reaction potential energy surface, three reaction pathways were identified. The first two reaction pathways start with H-atom abstraction from water by the O6 and N7 atoms in 9MG˙+ and are referred to as HAO6 and HAN7, respectively. The primary products of HAO6 and HAN7 reactions, including [9MG + HO6]+/[9MG + HN7]+ and ˙OH, react further to either form [8OH-9MG + HO6]˙+ and [8OH-9MG + HN7]˙+via C8-hydroxylation or form radical cations of 6-enol-guanine (6-enol-G˙+) and 7H-guanine (7HG˙+) via SN2-type methanol elimination. The third reaction pathway corresponds to the formation of 8OH-9MG+ by H elimination from the complex, referred to as HE. Among these product channels, [8OH-9MG + HN7]˙+ has the most favorable formation probability, especially in the presence of additional water molecules. This product may serve as a preceding structure to the 8-oxo-7,8-dihydroguanine lesion in DNA and has implications for health effects of radiation exposure and radiation therapy.
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Affiliation(s)
- Wenjing Zhou
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY 11367, USA. .,PhD Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, NY 10016, 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. .,PhD 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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