1
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Olivieri A, Nardi AN, D'Abramo M. Theoretical Insights into MutY Glycosylase DNA Repair Mechanism. Biochemistry 2024; 63:1991-1998. [PMID: 38990758 DOI: 10.1021/acs.biochem.4c00153] [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: 07/13/2024]
Abstract
Maintaining the integrity of the genome is fundamental to living organisms. To this end, nature developed several mechanisms to find and promptly repair DNA lesions. Among them, base excision repair (BER) enzymes evolved to efficiently carry out this task. Notably, the mechanisms allowing these proteins to search for, detect, and fix DNA damage on a biologically relevant time scale still remain partially unclear. By taking MutY, a BER enzyme implied in the repair of the 8-oxoguanine-adenine mismatches, as a model system, we shed some light on the repair mechanism through a theoretical-computational approach. First, we estimated the effect of the oxidation state of the MutY iron-sulfur cluster on the protein-DNA binding. Then, the redox thermodynamics of both the protein cluster and DNA nucleobases are calculated. Finally, the charge migration kinetics along the double strand bound to the enzyme has been evaluated. The rationalization of our results indicates that the search for DNA lesions is essentially dictated by the redox chemistry of the species involved, i.e., the iron-sulfur redox cofactor and the DNA bound to the enzyme.
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Affiliation(s)
- Alessio Olivieri
- Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy
| | | | - Marco D'Abramo
- Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy
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2
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Karwowski BT. The Influence of Oxidized Imino-Allantoin in the Presence of OXOG on Double Helix Charge Transfer: A Theoretical Approach. Int J Mol Sci 2024; 25:5962. [PMID: 38892152 PMCID: PMC11172559 DOI: 10.3390/ijms25115962] [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: 04/14/2024] [Revised: 05/19/2024] [Accepted: 05/28/2024] [Indexed: 06/21/2024] Open
Abstract
The genome is continuously exposed to a variety of harmful factors that result in a significant amount of DNA damage. This article examines the influence of a multi-damage site containing oxidized imino-allantoin (OXIa) and 7,8-dihydro-8-oxo-2'-deoxyguanosine (OXOdG) on the spatial geometry, electronic properties, and ds-DNA charge transfer. The ground stage of a d[A1OXIa2A3OXOG4A5]*d[T5C4T3C2T1] structure was obtained at the M06-2X/6-D95**//M06-2X/sto-3G level of theory in the condensed phase, with the energies obtained at the M06-2X/6-31++G** level. The non-equilibrated and equilibrated solvent-solute interactions were also considered. Theoretical studies reveal that the radical cation prefers to settle on the OXOG moiety, irrespective of the presence of OXIa in a ds-oligo. The lowest vertical and adiabatic ionization potential values were found for the OXOG:::C base pair (5.94 and 5.52 [eV], respectively). Conversely, the highest vertical and adiabatic electron affinity was assigned for OXIaC as follows: 3.15 and 3.49 [eV]. The charge transfers were analyzed according to Marcus' theory. The highest value of charge transfer rate constant for hole and excess electron migration was found for the process towards the OXOGC moiety. Surprisingly, the values obtained for the driving force and activation energy of electro-transfer towards OXIa2C4 located this process in the Marcus inverted region, which is thermodynamically unfavorable. Therefore, the presence of OXIa can slow down the recognition and removal processes of other DNA lesions. However, with regard to anticancer therapy (radio/chemo), the presence of OXIa in the structure of clustered DNA damage can result in improved cancer treatment outcomes.
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Affiliation(s)
- Boleslaw T Karwowski
- DNA Damage Laboratory of Food Science Department, Faculty of Pharmacy, Medical University of Lodz, ul. Muszynskiego 1, 90-151 Lodz, Poland
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3
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Rooman M, Pucci F. Estimating the Vertical Ionization Potential of Single-Stranded DNA Molecules. J Chem Inf Model 2023; 63:1766-1775. [PMID: 36877828 DOI: 10.1021/acs.jcim.2c01525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
The electronic properties of DNA molecules, defined by the sequence-dependent ionization potentials of nucleobases, enable long-range charge transport along the DNA stacks. This has been linked to a range of key physiological processes in the cells and to the triggering of nucleobase substitutions, some of which may cause diseases. To gain molecular-level understanding of the sequence dependence of these phenomena, we estimated the vertical ionization potential (vIP) of all possible nucleobase stacks in B-conformation, containing one to four Gua, Ade, Thy, Cyt, or methylated Cyt. To do this, we used quantum chemistry calculations and more precisely the second-order Møller-Plesset perturbation theory (MP2) and three double-hybrid density functional theory methods, combined with several basis sets for describing atomic orbitals. The calculated vIP of single nucleobases were compared to experimental data and those of nucleobase pairs, triplets, and quadruplets, to observed mutability frequencies in the human genome, reported to be correlated with vIP values. This comparison selected MP2 with the 6-31G* basis set as the best of the tested calculation levels. These results were exploited to set up a recursive model, called vIPer, which estimates the vIP of all possible single-stranded DNA sequences of any length based on the calculated vIPs of overlapping quadruplets. vIPer's vIP values correlate well with oxidation potentials measured by cyclic voltammetry and activities obtained through photoinduced DNA cleavage experiments, further validating our approach. vIPer is freely available on the github.com/3BioCompBio/vIPer repository.
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Affiliation(s)
- Marianne Rooman
- Computational Biology and Bioinformatics, Université Libre de Bruxelles, 1050 Brussels, Belgium.,Interuniversity Institute of Bioinformatics in Brussels, 1050 Brussels, Belgium
| | - Fabrizio Pucci
- Computational Biology and Bioinformatics, Université Libre de Bruxelles, 1050 Brussels, Belgium.,Interuniversity Institute of Bioinformatics in Brussels, 1050 Brussels, Belgium
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4
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Hu Z, Zhou Q, Jiao Z, Qin P, Wang F, Xia Y, Zhang T, Jie J, Su H. Low Energy Photoionization of Phosphorothioate DNA-Oligomers and Ensuing Hole Transfer. J Phys Chem B 2022; 126:8699-8707. [PMID: 36259641 DOI: 10.1021/acs.jpcb.2c05521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Phosphorothioate (PS) modified oligonucleotides (S-DNA) naturally exist in bacteria and archaea genome and are widely used as an antisense strategy in gene therapy. However, the introduction of PS as a redox active site may trigger distinct UV photoreactions. Herein, by time-resolved spectroscopy, we observe that 266 nm excitation of S-DNA d(Aps)20 and d(ApsA)10 leads to direct photoionization on the PS moiety to form hemi-bonded -P-S∴S-P- radicals, in addition to A base ionization to produce A+•/A(-H)•. Fluorescence spectroscopy and global analysis indicate that an unusual charge transfer state (CT) between the A and PS moiety might populate in competition with the common CT state among bases as key intermediate states responsible for S-DNA photoionization. Significantly, the photoionization bifurcating to PS and A moieties of S-DNA is discovered, suggesting that the PS moiety could capture the oxidized site and protect the remaining base against ionization lesion, shedding light on the understanding of its existence in living organisms.
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Affiliation(s)
- Zheng Hu
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Qian Zhou
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Zeqing Jiao
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Peixuan Qin
- University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - Fei Wang
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Ye Xia
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Tianfeng Zhang
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Jialong Jie
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Hongmei Su
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
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5
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Modeling Charge Transfer Reactions by Hopping between Electronic Ground State Minima: Application to Hole Transfer between DNA Bases. Molecules 2022; 27:molecules27217408. [DOI: 10.3390/molecules27217408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022] Open
Abstract
In this paper, we extend the previously described general model for charge transfer reactions, introducing specific changes to treat the hopping between energy minima of the electronic ground state (i.e., transitions between the corresponding vibrational ground states). We applied the theoretical–computational model to the charge transfer reactions in DNA molecules which still represent a challenge for a rational full understanding of their mechanism. Results show that the presented model can provide a valid, relatively simple, approach to quantitatively study such reactions shedding light on several important aspects of the reaction mechanism.
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6
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Nardi AN, Olivieri A, D'Abramo M. Rationalizing Sequence and Conformational Effects on the Guanine Oxidation in Different DNA Conformations. J Phys Chem B 2022; 126:5017-5023. [PMID: 35671051 PMCID: PMC9289878 DOI: 10.1021/acs.jpcb.2c02391] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
![]()
The effect of the
environment on the guanine redox potential is
studied by means of a theoretical–computational approach. Our
data, in agreement with previous experimental findings, clearly show
that the presence of consecutive guanine bases in both single- and
double-stranded DNA oligomers lowers their reduction potential. Such
an effect is even more marked when a G-rich quadruplex is considered,
where the oxidized form of guanine is particularly stabilized. To
the best of our knowledge, this is the first computational study reporting
on a quantitative estimate of the dependence of the guanine redox
potential on sequence and conformational effects in complex DNA molecules,
ranging from single-stranded DNA to G-quadruplex.
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Affiliation(s)
| | - Alessio Olivieri
- Department of Chemistry, Sapienza University of Rome, Rome, Italy 00185
| | - Marco D'Abramo
- Department of Chemistry, Sapienza University of Rome, Rome, Italy 00185
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7
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Balanikas E, Martinez-Fernandez L, Baldacchino G, Markovitsi D. Electron Holes in G-Quadruplexes: The Role of Adenine Ending Groups. Int J Mol Sci 2021; 22:ijms222413436. [PMID: 34948235 PMCID: PMC8704496 DOI: 10.3390/ijms222413436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 11/16/2022] Open
Abstract
The study deals with four-stranded DNA structures (G-Quadruplexes), known to undergo ionization upon direct absorption of low-energy UV photons. Combining quantum chemistry calculations and time-resolved absorption spectroscopy with 266 nm excitation, it focuses on the electron holes generated in tetramolecular systems with adenine groups at the ends. Our computations show that the electron hole is placed in a single guanine site, whose location depends on the position of the adenines at the 3' or 5' ends. This position also affects significantly the electronic absorption spectrum of (G+)● radical cations. Their decay is highly anisotropic, composed of a fast process (<2 µs), followed by a slower one occurring in ~20 µs. On the one hand, they undergo deprotonation to (G-H2)● radicals and, on the other, they give rise to a reaction product absorbing in the 300-500 nm spectral domain.
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Affiliation(s)
- Evangelos Balanikas
- LIDYL, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France; (E.B.); (G.B.)
| | - Lara Martinez-Fernandez
- Departamento de Química, Modúlo 13, Facultad de Ciencias and IADCHEM (Institute for Advanced Research in Chemistry), Campus de Excelencia UAM-CSIC, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
- Correspondence: (L.M.-F.); or (D.M.)
| | - Gérard Baldacchino
- LIDYL, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France; (E.B.); (G.B.)
| | - Dimitra Markovitsi
- LIDYL, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France; (E.B.); (G.B.)
- Correspondence: (L.M.-F.); or (D.M.)
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8
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Balanikas E, Banyasz A, Baldacchino G, Markovitsi D. Deprotonation Dynamics of Guanine Radical Cations †. Photochem Photobiol 2021; 98:523-531. [PMID: 34653259 DOI: 10.1111/php.13540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 10/08/2021] [Indexed: 01/25/2023]
Abstract
This review is dedicated to guanine radical cations (G+ )· that are precursors to oxidatively generated damage to DNA. (G+ )· are unstable in neutral aqueous solution and tend to lose a proton. The deprotonation process has been studied by time-resolved absorption experiments in which (G+ )· radicals are produced either by an electron abstraction reaction, using an external oxidant, or by low-energy/low-intensity photoionization of DNA. Both the position of the released proton and the dynamics of the process depend on the secondary DNA structure. While deprotonation in duplex DNA leads to (G-H1)· radicals, in guanine quadruplexes the (G-H2)· analogs are observed. Deprotonation in monomeric guanosine proceeds with a time constant of ˜60 ns; in genomic DNA, it is completed within 2 µs; and in guanine quadruplexes, it spans from at least 30 ns to over 50 µs. Such a deprotonation dynamics in four-stranded structures, extended over more than three decades of times, is correlated with the anisotropic structure of DNA and the mobility of its hydration shell. In this case, commonly used second-order reaction models are inappropriate for its description.
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Affiliation(s)
| | - Akos Banyasz
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette, F-91191, France.,Univ Lyon, ENS de Lyon, CNRS, UMR 5182, Université Claude Bernard Lyon 1, Laboratoire de Chimie, Lyon, F-69342, France
| | - Gérard Baldacchino
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette, F-91191, France
| | - Dimitra Markovitsi
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette, F-91191, France
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9
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Ripanti F, Fasolato C, Mazzarda F, Palleschi S, Ceccarini M, Li C, Bignami M, Bodo E, Bell SEJ, Mazzei F, Postorino P. Advanced Raman Spectroscopy Detection of Oxidative Damage in Nucleic Acid Bases: Probing Chemical Changes and Intermolecular Interactions in Guanosine at Ultralow Concentration. Anal Chem 2021; 93:10825-10833. [PMID: 34324303 PMCID: PMC8382216 DOI: 10.1021/acs.analchem.1c01049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
DNA/RNA synthesis precursors are especially vulnerable to damage induced by reactive oxygen species occurring following oxidative stress. Guanosine triphosphates are the prevalent oxidized nucleotides, which can be misincorporated during replication, leading to mutations and cell death. Here, we present a novel method based on micro-Raman spectroscopy, combined with ab initio calculations, for the identification, detection, and quantification of oxidized nucleotides at low concentration. We also show that the Raman signature in the terahertz spectral range (<100 cm-1) contains information on the intermolecular assembly of guanine in tetrads, which allows us to further boost the oxidative damage detection limit. Eventually, we provide evidence that similar analyses can be carried out on samples in very small volumes at very low concentrations by exploiting the high sensitivity of surface-enhanced Raman scattering combined with properly designed superhydrophobic substrates. These results pave the way for employing such advanced spectroscopic methods for quantitatively sensing the oxidative damage of nucleotides in the cell.
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Affiliation(s)
- Francesca Ripanti
- Department of Physics, Sapienza University of Rome, P.le A. Moro 5, Rome, Italy
| | - Claudia Fasolato
- Department of Physics and Geology, University of Perugia, Via Alessandro Pascoli, Perugia, Italy
| | - Flavia Mazzarda
- Department of Physics, Sapienza University of Rome, P.le A. Moro 5, Rome, Italy
| | - Simonetta Palleschi
- Department of Environment & Health, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy
| | - Marina Ceccarini
- National Centre for Rare Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy
| | - Chunchun Li
- School of Chemistry and Chemical Engineering, Queen's University of Belfast, Stranmillis Road, Belfast, Northern Ireland
| | - Margherita Bignami
- Department of Environment & Health, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy
| | - Enrico Bodo
- Department of Chemistry, Sapienza University of Rome, P.le A. Moro, 5, Rome, Italy
| | - Steven E J Bell
- School of Chemistry and Chemical Engineering, Queen's University of Belfast, Stranmillis Road, Belfast, Northern Ireland
| | - Filomena Mazzei
- Department of Environment & Health, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy
| | - Paolo Postorino
- Department of Physics, Sapienza University of Rome, P.le A. Moro 5, Rome, Italy
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10
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Zhang X, Jie J, Song D, Su H. Deprotonation of Guanine Radical Cation G •+ Mediated by the Protonated Water Cluster. J Phys Chem A 2020; 124:6076-6083. [PMID: 32585092 DOI: 10.1021/acs.jpca.0c03748] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Proton transfer is regarded as a fundamental process in chemical reactions of DNA molecules and continues to be an active research theme due to the connection with charge transport and oxidation damage of DNA. For the guanine radical cation (G•+) derived from one-electron oxidation, experiments suggest a facile proton transfer within the G•+:C base pair, and a rapid deprotonation from N1 in free base or single-strand DNA. To address the deprotonation mechanism, we perform a thorough investigation on deprotonation of G•+ in free G base by combining density functional theory (DFT) and laser flash photolysis spectroscopy. Experimentally, kinetics of deprotonation is monitored at temperatures varying from 280 to 298 K, from which the activation energy of 15.1 ± 1.5 kJ/mol is determined for the first time. Theoretically, four solvation models incorporating explicit waters and the polarized continuum model (PCM), i.e., 3H2O-PCM, 4H2O-PCM, 5H2O-PCM, and 7H2O-PCM models are used to calculate deprotonation potential energy profile, and the barriers of 5.5, 13.4, 14.4, and 13.7 kJ/mol are obtained, respectively. It is shown that at least four explicit waters are required for properly simulating the deprotonation reaction, where the participation of protonated water cluster plays key roles in facilitating the proton release from G•+.
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Affiliation(s)
- Xianwang Zhang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing 100048, P. R. China
| | - Jialong Jie
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Di Song
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Hongmei Su
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
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11
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Kumar A, Adhikary A, Sevilla MD, Close DM. One-electron oxidation of ds(5'-GGG-3') and ds(5'-G(8OG)G-3') and the nature of hole distribution: a density functional theory (DFT) study. Phys Chem Chem Phys 2020; 22:5078-5089. [PMID: 32073006 PMCID: PMC7058519 DOI: 10.1039/c9cp06244k] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Of particular interest in radiation-induced charge transfer processes in DNA is the extent of hole localization immediately after ionization and subsequent relaxation. To address this, we considered double stranded oligomers containing guanine (G) and 8-oxoguanine (8OG), i.e., ds(5'-GGG-3') and ds(5'-G8OGG-3') in B-DNA conformation. Using DFT, we calculated a variety of properties, viz., vertical and adiabatic ionization potentials, spin density distributions in oxidized stacks, solvent and solute reorganization energies and one-electron oxidation potential (E0) in the aqueous phase. Calculations for the vertical state of the -GGG- cation radical showed that the spin was found mainly (67%) on the middle G. However, upon relaxation to the adiabatic -GGG- cation radical, the spin localized (96%) on the 5'-G, as observed in experiments. Hole localizations on the middle G and 3'-G were higher in energy by 0.5 kcal mol-1 and 0.4 kcal mol-1, respectively, than that of 5'-G. In the -G8OGG- cation radical, the spin localized only on the 8OG in both vertical and adiabatic states. The calculated vertical ionization potentials of -GGG- and -G8OGG- stacks were found to be lower than that of the vertical ionization potential of a single G in DNA. The calculated E0 values of -GGG- and -G8OGG- stacks are 1.15 and 0.90 V, respectively, which owing to stacking effects are substantially lower than the corresponding experimental E0 values of their monomers (1.49 and 1.18 V, respectively). SOMO to HOMO level switching is observed in these oxidized stacks. Consequently, our calculations predict that local double oxidations in DNA will form triplet diradical states, which are especially significant for high LET radiations.
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Affiliation(s)
- Anil Kumar
- Department of Chemistry, Oakland University, Rochester, Michigan 48309, USA.
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12
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Lozinova TA, Lobanov AV, Lander AV, Brzhevskaya ON. Effect of Inorganic Phosphate on the Photoproduction of Hydrogen Peroxide in Frozen Aqueous Solutions of Adenine Derivatives. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2020. [DOI: 10.1134/s0036024420020223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Murray V, Hardie ME, Gautam SD. Comparison of Different Methods to Determine the DNA Sequence Preference of Ionising Radiation-Induced DNA Damage. Genes (Basel) 2019; 11:genes11010008. [PMID: 31861886 PMCID: PMC7016695 DOI: 10.3390/genes11010008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/09/2019] [Accepted: 12/18/2019] [Indexed: 11/29/2022] Open
Abstract
Ionising radiation (IR) is known to induce a wide variety of lesions in DNA. In this review, we compared three different techniques that examined the DNA sequence preference of IR-induced DNA damage at nucleotide resolution. These three techniques were: the linear amplification/polymerase stop assay, the end-labelling procedure, and Illumina next-generation genome-wide sequencing. The DNA sequence preference of IR-induced DNA damage was compared in purified DNA sequences including human genomic DNA. It was found that the DNA sequence preference of IR-induced DNA damage identified by the end-labelling procedure (that mainly detected single-strand breaks) and Illumina next-generation genome-wide sequencing (that mainly detected double-strand breaks) was at C nucleotides, while the linear amplification/polymerase stop assay (that mainly detected base damage) was at G nucleotides. A consensus sequence at the IR-induced DNA damage was found to be 5′-AGGC*C for the end-labelling technique, 5′-GGC*MH (where * is the cleavage site, M is A or C, H is any nucleotide except G) for the genome-wide technique, and 5′-GG* for the linear amplification/polymerase stop procedure. These three different approaches are important because they provide a deeper insight into the mechanism of action of IR-induced DNA damage.
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Affiliation(s)
- Vincent Murray
- Correspondence: ; Tel.: +61-2-9385-2028; Fax: +61-2-9385-1483
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14
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The Dynamics of Hole Transfer in DNA. Molecules 2019; 24:molecules24224044. [PMID: 31703470 PMCID: PMC6891780 DOI: 10.3390/molecules24224044] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 10/31/2019] [Accepted: 11/02/2019] [Indexed: 11/21/2022] Open
Abstract
High-energy radiation and oxidizing agents can ionize DNA. One electron oxidation gives rise to a radical cation whose charge (hole) can migrate through DNA covering several hundreds of Å, eventually leading to irreversible oxidative damage and consequent disease. Understanding the thermodynamic, kinetic and chemical aspects of the hole transport in DNA is important not only for its biological consequences, but also for assessing the properties of DNA in redox sensing or labeling. Furthermore, due to hole migration, DNA could potentially play an important role in nanoelectronics, by acting as both a template and active component. Herein, we review our work on the dynamics of hole transfer in DNA carried out in the last decade. After retrieving the thermodynamic parameters needed to address the dynamics of hole transfer by voltammetric and spectroscopic experiments and quantum chemical computations, we develop a theoretical methodology which allows for a faithful interpretation of the kinetics of the hole transport in DNA and is also capable of taking into account sequence-specific effects.
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15
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Hardie ME, Murray V. The sequence preference of gamma radiation-induced DNA damage as determined by a polymerase stop assay. Int J Radiat Biol 2019; 95:1613-1626. [PMID: 31498026 DOI: 10.1080/09553002.2019.1665216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Purpose: The aim of this paper was to investigate the sequence preference of ionizing radiation (IR)-induced DNA damage as assessed by a linear amplification/polymerase stop (LA/PS) assay. The LA/PS assay is able to detect a wide range of IR-induced DNA lesions and this technique was utilized to quantitatively determine the preferential sites of gamma irradiation-induced DNA lesions in three different DNA sequences.Materials and methods: This analysis was performed on an automated DNA sequencer with capillary electrophoresis and laser-induced fluorescence detection.Results: The main outcome of this study was that G nucleotides were preferentially found at IR-induced polymerase stop sites. The individual nucleotides at the IR-induced DNA damage sites were analyzed and a consensus sequence of 5'-GG* (where * indicates the damaged nucleotide) was observed. In a separate method of analysis, the dinucleotides and trinucleotides at the IR-induced DNA damage sites were examined and 5'-GG* and 5'-G*G dinucleotides and 5'-GG*G trinucleotides were found to be the most prevalent. The use of the LA/PS assay permits a large number of IR-induced DNA lesions to be detected in the one procedure including: double- and single-strand breaks, apurinic/apyrimidinic sites and base damage.Conclusions: It was concluded that 2,6-diamino-4-hydroxy-5-formamidopyrimidine (Fapy-G) and the degradation products of 8-oxoG were possibly the main lesions detected. To our knowledge, this is the first occasion that the DNA sequence preference of IR-induced DNA damage as detected by a LA/PS assay has been reported.
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Affiliation(s)
- Megan E Hardie
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Vincent Murray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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16
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Vogel S, Ebel K, Heck C, Schürmann RM, Milosavljević AR, Giuliani A, Bald I. Vacuum-UV induced DNA strand breaks - influence of the radiosensitizers 5-bromouracil and 8-bromoadenine. Phys Chem Chem Phys 2019; 21:1972-1979. [PMID: 30633275 DOI: 10.1039/c8cp06813e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Radiation therapy is a basic part of cancer treatment. To increase the DNA damage in carcinogenic cells and preserve healthy tissue at the same time, radiosensitizing molecules such as halogenated nucleobase analogs can be incorporated into the DNA during the cell reproduction cycle. In the present study 8.44 eV photon irradiation induced single strand breaks (SSB) in DNA sequences modified with the radiosensitizer 5-bromouracil (5BrU) and 8-bromoadenine (8BrA) are investigated. 5BrU was incorporated in the 13mer oligonucleotide flanked by different nucleobases. It was demonstrated that the highest SSB cross sections were reached, when cytosine and thymine were adjacent to 5BrU, whereas guanine as a neighboring nucleobase decreases the activity of 5BrU indicating that competing reaction mechanisms are active. This was further investigated with respect to the distance of guanine to 5BrU separated by an increasing number of adenine nucleotides. It was observed that the SSB cross sections were decreasing with an increasing number of adenine spacers between guanine and 5BrU until the SSB cross sections almost reached the level of a non-modified DNA sequence, which demonstrates the high sequence dependence of the sensitizing effect of 5BrU. 8BrA was incorporated in a 13mer oligonucleotide as well and the strand breaks were quantified upon 8.44 eV photon irradiation in direct comparison to a non-modified DNA sequence of the same composition. No clear enhancement of the SSB yield of the modified in comparison to the non-modified DNA sequence could be observed. Additionally, secondary electrons with a maximum energy of 3.6 eV were generated when using Si as a substrate giving rise to further DNA damage. A clear enhancement in the SSB yield can be ascertained, but to the same degree for both the non-modified DNA sequence and the DNA sequence modified with 8BrA.
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Affiliation(s)
- Stefanie Vogel
- Institute of Chemistry - Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany.
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17
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Kumar A, Sevilla MD. Excited States of One-Electron Oxidized Guanine-Cytosine Base Pair Radicals: A Time Dependent Density Functional Theory Study. J Phys Chem A 2019; 123:3098-3108. [PMID: 30896952 DOI: 10.1021/acs.jpca.9b00906] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
One-electron oxidized guanine (G•+) in DNA generates several short-lived intermediate radicals via proton transfer reactions resulting in the formation of neutral guanine radicals. The identification of these radicals in DNA is of fundamental interest to understand the early stages of DNA damage. Herein, we used time-dependent density functional theory (TD-ωB97XD-PCM/6-31G(3df,p)) to calculate the vertical excitation energies of one-electron oxidized G and G-cytosine (C) base pair in various protonation states: G•+, G(N1-H)•, and G(N2-H)•, as well as G•+-C, G(N1-H)•-(H+)C, G(N1-H)•-(N4-H+)C), G(N1-H)•-C, and G(N2-H)•-C in aqueous phase. The calculated UV-vis spectra of these radicals are in good agreement with the experiment for the G radical species when the calculated values are red-shifted by 40-70 nm. The present calculations show that the lowest energy transitions of proton transfer species (G(N1-H)•-(H+)C, G(N1-H)•-(N4-H+)C, and G(N1-H)•-C) are substantially red-shifted in comparison to the spectrum of G•+-C. The calculated spectrum of G(N2-H)•-C shows intense absorption (high oscillator strength), which matches the strong absorption in the experimental spectra of G(N2-H)• at 600 nm. The present calculations predict the lowest charge transfer transition of C → G•+ is π → π* in nature and lies in the UV region (3.4-4.3 eV) with small oscillator strength.
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Affiliation(s)
- Anil Kumar
- Department of Chemistry , Oakland University , Rochester , Michigan 48309 , United States
| | - Michael D Sevilla
- Department of Chemistry , Oakland University , Rochester , Michigan 48309 , United States
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18
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Diamantis P, Tavernelli I, Rothlisberger U. Vertical Ionization Energies and Electron Affinities of Native and Damaged DNA Bases, Nucleotides, and Pairs from Density Functional Theory Calculations: Model Assessment and Implications for DNA Damage Recognition and Repair. J Chem Theory Comput 2019; 15:2042-2052. [PMID: 30681847 DOI: 10.1021/acs.jctc.8b00645] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
To assess the effect of an 8-oxoguanine (8OG) defect base on the vertical ionization energies (VIEs) and electron affinities (VEAs) of DNA, density functional theory calculations were carried out for native and defect DNA bases and nucleotides, as well as for larger fragments containing one or multiple pairs. Absolute values of VIE and VEA under implicit solvation did not converge as a function of model size even up to the largest systems taken into consideration (3 base pairs/2 nucleotide pairs). Nonetheless, a consistent trend was observed for the relative difference in the VIE of native and damaged DNA showing that the defect was lowering the VIE by -0.1 eV for the largest fragments. This strongly suggests that the presence of 8OG makes the DNA more easily oxidizable and is in line with experimental evidence that a defect region can act as a sink of oxidative damage. In contrast, relative differences in VEA were very small and varied inconsistently around 0.01 eV. This seems to indicate that insertion of 8OG has a negligible effect on the electron capturing properties of DNA. Similar conclusions can be drawn by the adiabatic IEs and EAs computed for some of the larger fragments. Analysis of the hole and excess electron distributions was consistent with the above trends. The findings presented here support the possibility that a mechanism based on hole transport through DNA may be efficiently employed by the cell for the detection of defect bases.
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Affiliation(s)
- Polydefkis Diamantis
- Laboratory of Computational Chemistry and Biochemistry , École Polytechnique Fédérale de Lausanne , Swiss Federal Institute of Technology, CH-1015 Lausanne , Switzerland
| | - Ivano Tavernelli
- Laboratory of Computational Chemistry and Biochemistry , École Polytechnique Fédérale de Lausanne , Swiss Federal Institute of Technology, CH-1015 Lausanne , Switzerland
| | - Ursula Rothlisberger
- Laboratory of Computational Chemistry and Biochemistry , École Polytechnique Fédérale de Lausanne , Swiss Federal Institute of Technology, CH-1015 Lausanne , Switzerland
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19
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Lozinova TA, Lobanov AV, Lander AV. Effect of the Irradiation Conditions on the Yield of Hydrogen Peroxide in Frozen Aqueous Solutions of Adenine Derivatives. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2018. [DOI: 10.1134/s0036024418100175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Martínez‐Fernández L, Banyasz A, Markovitsi D, Improta R. Topology Controls the Electronic Absorption and Delocalization of Electron Holes in Guanine Quadruplexes. Chemistry 2018; 24:15185-15189. [DOI: 10.1002/chem.201803222] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Indexed: 12/21/2022]
Affiliation(s)
| | - Akos Banyasz
- LIDYL, CEA, CNRSUniversité Paris-Saclay 91191 Gif-sur-Yvette France
| | | | - Roberto Improta
- LIDYL, CEA, CNRSUniversité Paris-Saclay 91191 Gif-sur-Yvette France
- Istituto di Biostrutture e BioimmaginiCNR Via Mezzocannone 16 80134 Napoli Italy
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21
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Capobianco A, Landi A, Peluso A. Modeling DNA oxidation in water. Phys Chem Chem Phys 2018; 19:13571-13578. [PMID: 28513687 DOI: 10.1039/c7cp02029e] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A novel set of hole-site energies and electronic coupling parameters to be used, in the framework of the simplest tight-binding approximation, for predicting DNA hole trapping efficiencies and rates of hole transport in oxidized DNA is proposed. The novel parameters, significantly different from those previously reported in the literature, have been inferred from reliable density functional calculations, including both the sugar-phosphate ionic backbone and the effects of the aqueous environment. It is shown that most of the experimental oxidation free energies of DNA tracts and of oligonucleotides available from photoelectron spectroscopy and voltammetric measurements are reproduced with great accuracy, without the need for introducing sequence dependent parameters.
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Affiliation(s)
- Amedeo Capobianco
- Dipartimento di Chimica e Biologia "Adolfo Zambelli", Università di Salerno, I-84084 Fisciano (SA), Italy.
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22
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The optical properties of adenine cation in different oligonucleotides: a PCM/TD-DFT study. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2223-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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23
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Zheng L, Greenberg MM. DNA Damage Emanating From a Neutral Purine Radical Reveals the Sequence Dependent Convergence of the Direct and Indirect Effects of γ-Radiolysis. J Am Chem Soc 2017; 139:17751-17754. [PMID: 29190086 DOI: 10.1021/jacs.7b10942] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Nucleobase radicals are the major intermediates generated by the direct (e.g., dA•+) and indirect (e.g., dA•) effects of γ-radiolysis. dA• was independently generated in DNA for the first time. The dA•+/dA• equilibrium, and consequently the reactivity in DNA, is significantly shifted toward the radical cation by a flanking dA. Tandem lesions emanating from dA• are the major products when the reactive intermediate is flanked by a 5'-dGT. In contrast, when dA• is flanked by dA, the increased dA•+ pKa results in DNA damage arising from hole transfer. This is the first demonstration that sequence effects lead to the intersection of the direct and indirect effects of ionizing radiation.
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Affiliation(s)
- Liwei Zheng
- Department of Chemistry, Johns Hopkins University , 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Marc M Greenberg
- Department of Chemistry, Johns Hopkins University , 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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24
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Chakraborty R, Ghosh D. The effect of sequence on the ionization of guanine in DNA. Phys Chem Chem Phys 2016; 18:6526-33. [PMID: 26864778 DOI: 10.1039/c5cp07804k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The accurate estimation of the ionization energies and understanding the nature of the ionized states of the nucleic acid bases (NABs) are crucial to the understanding of the DNA damage mechanism. The vertical ionization energy (VIE) of guanine is the lowest among the NABs and the ionization energies are strongly affected by the environment, such as solvation and characteristics of nearby NABs. Therefore, we investigate the sequence dependence of the VIEs of guanine in B-DNA. We use the equation of motion coupled cluster method for the estimation of ionization potential with single and double excitations (EOM-IP-CCSD) and density functional theory with dispersion corrected ωB97x-D for the estimation of VIEs. A significant amount of non-additivity or cooperativity, directly proportional to charge delocalization, is noticed in the change in VIE due to the interaction with the nearby NABs. While the change in VIE due to base pairing originates predominantly from charge-dipole interactions, stacking between base pairs is a more complicated balance of dispersion and charge-dipole interactions as well as stabilization due to the delocalization of the positive charge. The long range interactions are however dominated by 1/r(3) distance dependence which shows the major role played by charge-dipole interactions. The extent of localization of positive holes on guanine is also estimated for various sequences.
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Affiliation(s)
- Rahul Chakraborty
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Debashree Ghosh
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India.
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25
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Lozinova TA, Lobanov AV, Lander AV. Photoinduced formation of hydrogen peroxide in aqueous solutions of adenine derivatives at 77 K. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2016. [DOI: 10.1134/s0036024416110157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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26
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Tan SYS, Izgorodina EI. Comparison of the Effective Fragment Potential Method with Symmetry-Adapted Perturbation Theory in the Calculation of Intermolecular Energies for Ionic Liquids. J Chem Theory Comput 2016; 12:2553-68. [DOI: 10.1021/acs.jctc.6b00141] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Samuel Y. S. Tan
- School of Chemistry, Monash University, 17 Rainforest
Walk, Clayton, Victoria 3800, Australia
| | - Ekaterina I. Izgorodina
- School of Chemistry, Monash University, 17 Rainforest
Walk, Clayton, Victoria 3800, Australia
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27
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Harris MA, Mishra AK, Young RM, Brown KE, Wasielewski MR, Lewis FD. Direct Observation of the Hole Carriers in DNA Photoinduced Charge Transport. J Am Chem Soc 2016; 138:5491-4. [DOI: 10.1021/jacs.6b00702] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Michelle A. Harris
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Ashutosh Kumar Mishra
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Ryan M. Young
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Kristen E. Brown
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Frederick D. Lewis
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
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28
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Capobianco A, Caruso T, Peluso A. Hole delocalization over adenine tracts in single stranded DNA oligonucleotides. Phys Chem Chem Phys 2016; 17:4750-6. [PMID: 25589467 DOI: 10.1039/c4cp04282d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Adiabatic ionization energies of single stranded DNA oligonucleotides containing adenine tracts of different sizes have been computed at the DFT level and compared with the oxidation potentials determined by differential pulse voltammetry. Geometry optimizations have been performed at the full quantum mechanical level, including the sugar phosphate backbone and solvent effects. The observed progressive lowering of the ionization energy upon increasing the number of consecutive adenines is well predicted, the computed ionization potential shifts being in very good agreement with the experimental outcomes, both by using pure and hybrid functionals. The spin density of the oligonucleotide radical cations is distributed almost over the whole adenine tract, forming delocalized polarons.
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Affiliation(s)
- Amedeo Capobianco
- Dipartimento di Chimica e Biologia, Università di Salerno, I-84084 Fisciano, SA, Italy.
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29
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Karwowski BT. The influence of phosphorothioate on charge migration in single and double stranded DNA: a theoretical approach. Phys Chem Chem Phys 2015. [PMID: 26219639 DOI: 10.1039/c5cp01382h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In this study the influence of the phosphorothioate internucleotide bond on the electronic properties of single and double-stranded short nucleotides has been investigated at the M06-2X/6-31+G** level of theory in the gaseous phase. Due to the chirality of the phosphorus atom in a phosphorothioate (PT) internucleotide diester bond, the adiabatic/vertical mode of electron affinity/ionization potential, spin density and molecular orbital distribution, as well as structural analysis were taken under consideration for the single stranded (ss) R(P) and S(P) diastereomers of d[G(PS)G] and for double stranded (ds) d[G(PS)G]*d[C(PO)C], in comparison with the corresponding parent phosphate compounds. Moreover, the excitation states, HOMO and LUMO energies were calculated using a TD-DFT methodology at the M06-2X/6-31+G**//M06-2X/6-31++G** level of theory in the aqueous phase. The obtained results show that the PT plays a significant role in the case of ss-oligonucleotides, and to a much smaller extent in ds-oligomers.
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Affiliation(s)
- Boleslaw T Karwowski
- Food Science Department, Medical University of Lodz, ul. Muszynskiego 1, 90-151 Lodz, Poland.
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30
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Sun H, Zhang S, Sun Z. Applicability of optimal functional tuning in density functional calculations of ionization potentials and electron affinities of adenine–thymine nucleobase pairs and clusters. Phys Chem Chem Phys 2015; 17:4337-45. [DOI: 10.1039/c4cp05470a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Successful application of optimally tuned long-range corrected functionals for calculation of vertical ionization potentials and electron affinities of various adenine–thymine nucleobase pairs and clusters is demonstrated.
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Affiliation(s)
- Haitao Sun
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062
- P. R. China
| | - Shian Zhang
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062
- P. R. China
| | - Zhenrong Sun
- State Key Laboratory of Precision Spectroscopy
- Department of Physics
- East China Normal University
- Shanghai 200062
- P. R. China
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31
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Sequence dependence of electron-induced DNA strand breakage revealed by DNA nanoarrays. Sci Rep 2014; 4:7391. [PMID: 25487346 PMCID: PMC4260214 DOI: 10.1038/srep07391] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 11/20/2014] [Indexed: 01/18/2023] Open
Abstract
The electronic structure of DNA is determined by its nucleotide sequence, which is for instance exploited in molecular electronics. Here we demonstrate that also the DNA strand breakage induced by low-energy electrons (18 eV) depends on the nucleotide sequence. To determine the absolute cross sections for electron induced single strand breaks in specific 13 mer oligonucleotides we used atomic force microscopy analysis of DNA origami based DNA nanoarrays. We investigated the DNA sequences 5′-TT(XYX)3TT with X = A, G, C and Y = T, BrU 5-bromouracil and found absolute strand break cross sections between 2.66 · 10−14 cm2 and 7.06 · 10−14 cm2. The highest cross section was found for 5′-TT(ATA)3TT and 5′-TT(ABrUA)3TT, respectively. BrU is a radiosensitizer, which was discussed to be used in cancer radiation therapy. The replacement of T by BrU into the investigated DNA sequences leads to a slight increase of the absolute strand break cross sections resulting in sequence-dependent enhancement factors between 1.14 and 1.66. Nevertheless, the variation of strand break cross sections due to the specific nucleotide sequence is considerably higher. Thus, the present results suggest the development of targeted radiosensitizers for cancer radiation therapy.
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32
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Capobianco A, Peluso A. The oxidization potential of AA steps in single strand DNA oligomers. RSC Adv 2014. [DOI: 10.1039/c4ra09270h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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33
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Marenich AV, Ho J, Coote ML, Cramer CJ, Truhlar DG. Computational electrochemistry: prediction of liquid-phase reduction potentials. Phys Chem Chem Phys 2014; 16:15068-106. [PMID: 24958074 DOI: 10.1039/c4cp01572j] [Citation(s) in RCA: 314] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This article reviews recent developments and applications in the area of computational electrochemistry. Our focus is on predicting the reduction potentials of electron transfer and other electrochemical reactions and half-reactions in both aqueous and nonaqueous solutions. Topics covered include various computational protocols that combine quantum mechanical electronic structure methods (such as density functional theory) with implicit-solvent models, explicit-solvent protocols that employ Monte Carlo or molecular dynamics simulations (for example, Car-Parrinello molecular dynamics using the grand canonical ensemble formalism), and the Marcus theory of electronic charge transfer. We also review computational approaches based on empirical relationships between molecular and electronic structure and electron transfer reactivity. The scope of the implicit-solvent protocols is emphasized, and the present status of the theory and future directions are outlined.
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Affiliation(s)
- Aleksandr V Marenich
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, 207 Pleasant Street S.E., Minneapolis, MN 55455-0431, USA.
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34
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Kumar A, Sevilla MD. Proton transfer induced SOMO-to-HOMO level switching in one-electron oxidized A-T and G-C base pairs: a density functional theory study. J Phys Chem B 2014; 118:5453-8. [PMID: 24798145 PMCID: PMC4032191 DOI: 10.1021/jp5028004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
In the present study,
we show that for one-electron oxidized A-T
or G-C base pairs the singly occupied molecular orbital (SOMO) is
located on A or G and is lower in energy than the doubly occupied
highest-occupied molecular orbital (HOMO) localized to the pyrimidines,
T or C. This directs second ionizations to the pyrimidine bases resulting
in triplet state diradical dications, (A•+-T•+) and (G•+-C•+). On interbase proton transfer, the SOMO and HOMO levels switch
and the second oxidation is redirected to G and A. For G-C, the doubly
oxidized singlet G(-H)+-C(H+) is more stable
than its triplet (G•+-C•+); however,
for A-T, the triplet (A•+-T•+)
lies lowest in energy. The study demonstrates that double ionization
of the A-T base pair results in a triplet dication diradical, which
is more stable than the proton-transferred triplet or singlet species;
whereas, double ionization of the G-C base pair, the proton transferred
doubly oxidized singlet, G(-H)+-C(H+), is more
stable and has both oxidations on guanine. In DNA, with both A-T and G-C, multiple oxidations would transfer
to the guanine base alone.
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Affiliation(s)
- Anil Kumar
- Department of Chemistry, Oakland University , Rochester, Michigan 48309, United States
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35
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Lin Y, Wang H, Wu Y, Gao S, Schaefer III HF. Proton-transfer in hydrogenated guanine–cytosine trimer neutral species, cations, and anions embedded in B-form DNA. Phys Chem Chem Phys 2014; 16:6717-25. [DOI: 10.1039/c3cp54904f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Simeon TM, Ratner MA, Schatz GC. Nature of noncovalent interactions in catenane supramolecular complexes: calibrating the MM3 force field with ab initio, DFT, and SAPT methods. J Phys Chem A 2013; 117:7918-27. [PMID: 23941280 DOI: 10.1021/jp400051b] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The design and assembly of mechanically interlocked molecules, such as catenanes and rotaxanes, are dictated by various types of noncovalent interactions. In particular, [C-H···O] hydrogen-bonding and π-π stacking interactions in these supramolecular complexes have been identified as important noncovalent interactions. With this in mind, we examined the [3]catenane 2·4PF6 using molecular mechanics (MM3), ab initio methods (HF, MP2), several versions of density functional theory (DFT) (B3LYP, M0X), and the dispersion-corrected method DFT-D3. Symmetry adapted perturbation theory (DFT-SAPT) provides the highest level of theory considered, and we use the DFT-SAPT results both to calibrate the other electronic structure methods, and the empirical potential MM3 force field that is often used to describe larger catenane and rotaxane structures where [C-H···O] hydrogen-bonding and π-π stacking interactions play a role. Our results indicate that the MM3 calculated complexation energies agree qualitatively with the energetic ordering from DFT-SAPT calculations with an aug-cc-pVTZ basis, both for structures dominated by [C-H···O] hydrogen-bonding and π-π stacking interactions. When the DFT-SAPT energies are decomposed into components, we find that electrostatic interactions dominate the [C-H···O] hydrogen-bonding interactions, while dispersion makes a significant contribution to π-π stacking. Another important conclusion is that DFT-D3 based on M06 or M06-2X provides interaction energies that are in near-quantitative agreement with DFT-SAPT. DFT results without the D3 correction have important differences compared to DFT-SAPT, while HF and even MP2 results are in poor agreement with DFT-SAPT.
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Affiliation(s)
- Tomekia M Simeon
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.
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37
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Capobianco A, Caruso T, Celentano M, D'Ursi AM, Scrima M, Peluso A. Stacking interactions between adenines in oxidized oligonucleotides. J Phys Chem B 2013; 117:8947-53. [PMID: 23837863 DOI: 10.1021/jp404133a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effects of stacking interactions on the oxidation potentials of single strand oligonucleotides containing up to four consecutive adenines, alternated with thymines and cytosines in different sequences and ratios, have been determined by means of differential pulse voltammetry. Voltammetric measurements point toward the establishment in solution of structured oligonucleotide conformations, in which the nucleobases are well stacked altogether. Molecular dynamics simulations confirm that finding, indicating that single strands assume geometrical parameters characteristic of the B-DNA form. The analysis of the voltammetric signals in terms of a simple effective tight binding quantum model leads one to infer a robust set of parameters for treating hole transfer in one-electron-oxidized DNA containing adenines and thymines.
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Affiliation(s)
- Amedeo Capobianco
- Dipartimento di Chimica e Biologia, Università di Salerno, I-84084 Fisciano, Salerno, Italy
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Rooman M, Wintjens R. Sequence and conformation effects on ionization potential and charge distribution of homo-nucleobase stacks using M06-2X hybrid density functional theory calculations. J Biomol Struct Dyn 2013; 32:532-45. [PMID: 23582046 PMCID: PMC3919198 DOI: 10.1080/07391102.2013.783508] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
DNA is subject to oxidative damage due to radiation or by-products of cellular metabolism, thereby creating electron holes that migrate along the DNA stacks. A systematic computational analysis of the dependence of the electronic properties of nucleobase stacks on sequence and conformation was performed here, on the basis of single- and double-stranded homo-nucleobase stacks of 1-10 bases or 1-8 base pairs in standard A-, B-, and Z-conformation. First, several levels of theory were tested for calculating the vertical ionization potentials of individual nucleobases; the M06-2X/6-31G* hybrid density functional theory method was selected by comparison with experimental data. Next, the vertical ionization potential, and the Mulliken charge and spin density distributions were calculated and considered on all nucleobase stacks. We found that (1) the ionization potential decreases with the number of bases, the lowest being reached by Gua≡Cyt tracts; (2) the association of two single strands into a double-stranded tract lowers the ionization potential significantly (3) differences in ionization potential due to sequence variation are roughly three times larger than those due to conformational modifications. The charge and spin density distributions were found (1) to be located toward the 5'-end for single-stranded Gua-stacks and toward the 3'-end for Cyt-stacks and basically delocalized over all bases for Ade- and Thy-stacks; (2) the association into double-stranded tracts empties the Cyt- and Thy-strands of most of the charge and all the spin density and concentrates them on the Gua- and Ade-strands. The possible biological implications of these results for transcription are discussed.
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Affiliation(s)
- Marianne Rooman
- a BioModeling, BioInformatics and BioProcesses Department , CP 165/61 Université Libre de Bruxelles , 50 Roosevelt ave, 1050 Brussels , Belgium
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Breindel AJ, Stuart RE, Bock WJ, Stelter DN, Kravec SM, Conwell EM. Hole Wave Functions and Transport with Deazaadenines Replacing Adenines in DNA. J Phys Chem B 2013; 117:3086-90. [DOI: 10.1021/jp310636k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander J. Breindel
- Department
of Physics and ‡Department of Chemistry, University of Rochester, Rochester,
New York 14627, United States
| | - Rachel E. Stuart
- Department
of Physics and ‡Department of Chemistry, University of Rochester, Rochester,
New York 14627, United States
| | - William J. Bock
- Department
of Physics and ‡Department of Chemistry, University of Rochester, Rochester,
New York 14627, United States
| | - David N. Stelter
- Department
of Physics and ‡Department of Chemistry, University of Rochester, Rochester,
New York 14627, United States
| | - Shane M. Kravec
- Department
of Physics and ‡Department of Chemistry, University of Rochester, Rochester,
New York 14627, United States
| | - Esther M. Conwell
- Department
of Physics and ‡Department of Chemistry, University of Rochester, Rochester,
New York 14627, United States
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40
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Renaud N, Berlin YA, Lewis FD, Ratner MA. Between superexchange and hopping: an intermediate charge-transfer mechanism in poly(A)-poly(T) DNA hairpins. J Am Chem Soc 2013; 135:3953-63. [PMID: 23402652 DOI: 10.1021/ja3113998] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We developed a model for hole migration along relatively short DNA hairpins with fewer that seven adenine (A):thymine (T) base pairs. The model was used to simulate hole migration along poly(A)-poly(T) sequences with a particular emphasis on the impact of partial hole localization on the different rate processes. The simulations, performed within the framework of the stochastic surrogate Hamiltonian approach, give values for the arrival rate in good agreement with experimental data. Theoretical results obtained for hairpins with fewer than three A:T base pairs suggest that hole transfer along short hairpins occurs via superexchange. This mechanism is characterized by the exponential distance dependence of the arrival rate on the donor/acceptor distance, k(a) ≃ e(-βR), with β = 0.9 Å(-1). For longer systems, up to six A:T pairs, the distance dependence follows a power law k(a) ≃ R(-η) with η = 2. Despite this seemingly clear signature of unbiased hopping, our simulations show the complete delocalization of the hole density along the entire hairpin. According to our analysis, the hole transfer along relatively long sequences may proceed through a mechanism which is distinct from both coherent single-step superexchange and incoherent multistep hopping. The criterion for the validity of this mechanism intermediate between superexchange and hopping is proposed. The impact of partial localization on the rate of hole transfer between neighboring A bases was also investigated.
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Affiliation(s)
- Nicolas Renaud
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA.
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41
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Bravaya KB, Epifanovsky E, Krylov AI. Four Bases Score a Run: Ab Initio Calculations Quantify a Cooperative Effect of H-Bonding and π-Stacking on the Ionization Energy of Adenine in the AATT Tetramer. J Phys Chem Lett 2012; 3:2726-2732. [PMID: 26295899 DOI: 10.1021/jz3011139] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Benchmark calculations of the lowest ionized state of the (A:T)2 (mixed adenine-thymine) cluster at the geometry taken from the DNA X-ray structure are presented. Vertical ionization energies (IEs) computed by the equation-of-motion coupled-cluster method with single and double substitutions are reported and analyzed. The shift in IE relative to the monomer (A) is -0.7 eV. The performance of the widely used B3LYP, ωB97X-D, and M06-2X functionals with respect to their ability to describe energetics and the character (localization versus delocalization) of the ionized states is also investigated. The shifts in IEs caused by H-bonding and stacking interactions are analyzed in terms of additive versus cooperative effects. It is found that the cooperative effect accounts for more than 20% of the shift in IE relative to the monomer. The cooperative effect and, consequently, the magnitude of the shift are well reproduced by the hybrid quantum mechanics/molecular mechanics scheme in which neutral thymine bases are represented by point charges.
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Affiliation(s)
- Ksenia B Bravaya
- †Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Evgeny Epifanovsky
- †Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
- ‡Department of Chemistry, University of California, Berkeley, California 94720, United States and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Anna I Krylov
- †Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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42
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Kumar A, Pottiboyina V, Sevilla MD. One-electron oxidation of neutral sugar radicals of 2'-deoxyguanosine and 2'-deoxythymidine: a density functional theory (DFT) study. J Phys Chem B 2012; 116:9409-16. [PMID: 22793263 DOI: 10.1021/jp3059068] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One electron oxidation of neutral sugar radicals has recently been suggested to lead to important intermediates in the DNA damage process culminating in DNA strand breaks. In this work, we investigate sugar radicals in a DNA model system to understand the energetics of sugar radical formation and oxidation. The geometries of neutral sugar radicals C(1')(•), C(2')(•), C(3')(•), C(4')(•), and C(5')(•) of 2'-deoxyguanosine (dG) and 2'-deoxythymidine (dT) were optimized in the gas phase and in solution using the B3LYP and ωB97x functionals and 6-31++G(d) basis set. Their corresponding cations (C(1')(+), C(2')(+), C(3')(+), C(4')(+), and C(5')(+)) were generated by removing an electron (one-electron oxidation) from the neutral sugar radicals, and their geometries were also optimized using the same methods and basis set. The calculation predicts the relative stabilities of the neutral sugar radicals in the order C(1')(•) > C(4')(•) > C(5')(•) > C(3')(•) > C(2')(•), respectively. Of the neutral sugar radicals, C(1')(•) has the lowest vertical ionization potential (IP(vert)), ca. 6.33 eV in the gas phase and 4.71 eV in solution. C(2')(•) has the highest IP(vert), ca. 8.02 eV, in the gas phase, and the resultant C(2') cation is predicted to undergo a barrierless hydride transfer from the C(1') site to produce the C(1') cation. One electron oxidation of C(2')(•) in dG is predicted to result in a low lying triplet state consisting of G(+•) and C(2')(•). The 5',8-cyclo-2'-deoxyguanosin-7-yl radical formed by intramolecular bonding between C(5')(•) and C(8) of guanine transfers spin density from C(5') site to guanine, and this structure has IP(vert) 6.25 and 5.48 eV in the gas phase and in solution.
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Affiliation(s)
- Anil Kumar
- Department of Chemistry, Oakland University, Rochester, Michigan 48309, USA
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DFT studies on one-electron oxidation and one-electron reduction for 2- and 4-aminopyridines. J Mol Model 2012; 18:4367-80. [PMID: 22585356 PMCID: PMC3429776 DOI: 10.1007/s00894-012-1446-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 04/23/2012] [Indexed: 11/28/2022]
Abstract
Quantum-chemical calculations {DFT(B3LYP)/6-311+G(d,p)} were performed for all possible tautomers (aromatic and nonaromatic) of neutral 2- and 4-aminopyridines and their oxidized and reduced forms. One-electron oxidation has no important effect on the tautomeric preference for 2-aminopyridine. The amine tautomer is favored. However, oxidation increases the stability of the imine NH tautomer, and its contribution in the tautomeric mixture cannot be neglected. In the case of 4-aminopyridine, one-electron oxidation increases the stability of both the amine and imine NH tautomers. Consequently, they possess very close energies. As major tautomers, they dictate the composition of the tautomeric mixture. The CH tautomers may be considered as very rare forms for both neutral and oxidized aminopyridines. A reverse situation takes place for the reduced forms of aminopyridines. One-electron reduction favors the C3 atom for the labile proton for both aminopyridines. This may partially explain the origin of the CH tautomers for the anionic states of nucleobases containing the exo NH2 group.
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Cerón-Carrasco JP, Requena A, Jacquemin D. Impact of DFT functionals on the predicted magnesium–DNA interaction: an ONIOM study. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1188-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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45
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Consequences of one-electron oxidation and one-electron reduction for 4-aminopyrimidine—DFT studies. J Mol Model 2012; 18:3523-33. [DOI: 10.1007/s00894-012-1358-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 01/08/2012] [Indexed: 10/14/2022]
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46
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Cerón-Carrasco JP, Jacquemin D, Cauët E. Cisplatin cytotoxicity: a theoretical study of induced mutations. Phys Chem Chem Phys 2012; 14:12457-64. [DOI: 10.1039/c2cp40515f] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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47
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Cerón-Carrasco JP, Jacquemin D. Interplay between hydroxyl radical attack and H-bond stability in guanine–cytosine. RSC Adv 2012. [DOI: 10.1039/c2ra22389a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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48
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Pottiboyina V, Kumar A, Sevilla MD. Formation of N-N cross-links in DNA by reaction of radiation-produced DNA base pair diradicals: a DFT study. J Phys Chem B 2011; 115:15090-7. [PMID: 22050209 PMCID: PMC3240691 DOI: 10.1021/jp207873a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study employs DFT (density functional theory) to investigate the formation of hydrazine-like (N-N) cross-linked structures between DNA base pair diradicals that are likely to result from the interaction of high linear energy transfer (LET) radiation, such as ion-beam radiation, with DNA. In our calculations, we generated the guanine (G), cytosine (C), adenine (A), and thymine (T) radicals by removing one hydrogen atom from an N-H bond involved in the normal base pairing. The radical species formed are those that naturally result from one-electron oxidation of the bases followed by deprotonation. N-N cross-links between G and C or A and T diradicals were studied using the BHandHLYP, B3LYP, M06, and M06-2X density functionals and 6-31G* basis set. From a comparison to several test cases performed with the G3B3 method, which gives thermodynamically reliable values, we found that calculations employing the BHandHLYP/6-31G* method predict the best estimates of bonding energies for hydrazine-like structures. Our study shows that the N-N cross-link formed between guanine radical and a neutral cytosine is endothermic in nature but can form metastable structures. However, the reactions between two DNA base radicals (diradical) to form several N-N cross-linked structures are found to be highly exothermic in nature. The N-N cross-links formed between various G-C, G-G, and C-C diradicals have binding energies in the range of ca. -54 to -68, -41 to -47, and -67 to -75 kcal/mol, respectively, whereas A-T, A-A, and T-T have binding energies of -80, -60, and -98 kcal/mol, respectively. In all purine-pyrimidine N-N cross-linked structures, the highest occupied molecular orbital (HOMO) is found to be localized on the purine moiety and the lowest unoccupied molecular orbital (LUMO) is on the pyrimidine moiety.
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Affiliation(s)
- Venkata Pottiboyina
- Department of Chemistry, Oakland University, Rochester, Michigan 48309, United States
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49
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Pavanello M, Neugebauer J. Modelling charge transfer reactions with the frozen density embedding formalism. J Chem Phys 2011; 135:234103. [DOI: 10.1063/1.3666005] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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50
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Wu J, Albrecht L, Boyd RJ. Effect of counterions on the protonation state in a poly(G)-poly(C) radical cation. J Phys Chem B 2011; 115:14885-90. [PMID: 22029377 DOI: 10.1021/jp2092863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The proton transfer process from a guanine to its complementary cytosine in a B-form d[GG] radical cation is investigated theoretically. The d[GG] radical cation is optimized by the ONIOM + PCM method. In this two-layer ONIOM method, the high layer consists of the π-stacked complementary base pairs with a hole charge, which is treated at the B97D/6-31G(d) level. The low layer includes the sugar-phosphate backbone and sodium ions, which is treated with the Amber99SB/Parmbsc0 force field. Our calculations reveal that the stabilization of the deprotonated state in d[GG] oligomers is related to the location of sodium ions. When sodium ions are located near phosphate groups, the proton prefers bonding with the guanine, and 80% of the hole charge is delocalized on the guanine residues. When sodium ions are placed in the major groove, the deprotonated state is favorable, and 70% of the hole charge localizes on the corresponding guanine-cytosine pair. According to the natural bond orbital analysis, the N-H···N hydrogen bond between the guanine-cytosine pair provides an important contribution to the stabilization of the deprotonated state. Stabilization of this hydrogen bond is very sensitive to the d[GG] oligomer configuration. In summary, the proton transfer process in a guanine-cytosine pair of poly(G)-poly(C) radical cations is largely affected by the arrangement of counterions.
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Affiliation(s)
- Jian Wu
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
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