Photosensitized formation of 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-hydroxy-2'-deoxyguanosine) in DNA by riboflavin: a nonsinglet oxygen-mediated reaction

Kasai, Hiroshi; Yamaizumi, Ziro; Berger, M.; Cadet, Jean

doi:10.1021/ja00050a078

Cited by 344 publications

(303 citation statements)

References 0 publications

Supporting

Mentioning

291

Contrasting

Unclassified

Order By: Relevance

“…The triplet is a powerful one-electron oxidant that initiates electron transfer from an adjacent nucleobase to form the AQ radical anion and a base radical cation (23)(24)(25). The AQ radical anion is consumed by reaction with O 2 to form superoxide, and the base radical cation can migrate through the DNA by hopping until it is trapped (usually at a guanine) by reaction with H 2 O and͞or O 2 (26,27). This process forms lesions at guanines that yield strand breaks when the sample is treated with piperidine.…”

Section: Resultsmentioning

confidence: 99%

Effect of condensate formation on long-distance radical cation migration in DNA

Das

Schuster

2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Long-distance radical cation transport was studied in DNA condensates. Linearized pUC19 plasmid was ligated to an oligomer containing a covalently linked anthraquinone group and six regularly spaced GG steps, which serve as traps for the migrating radical cation. Treatment of the linear, ligated plasmid with spermidine results in formation of condensates that were detected by light scattering and observed by transmission electron microscopy. Irradiation of the anthraquinone group in the condensate causes long-distance charge migration, which is detected by reaction at the remote guanines. The efficiency of charge migration in the condensate is significantly less than it is for the corresponding oligomer in solution. This result is attributed to a lower mobility for the migrating radical cation in the condensate, which is caused by inhibited formation of charge-transfer-effective states.charge transfer ͉ oxidative damage I t is well known that DNA is damaged by reactive chemical species. Extensive studies have shown that the one-electron oxidation of an oligonucleotide in solution creates a nucleobase radical cation (electron ''hole'') that may migrate hundreds of angstroms through duplex DNA before it is irreversibly trapped by reaction with H 2 O or O 2 (1-3). Trapping occurs most commonly at a guanine, because it is the base with the lowest ionization potential (4), and this reaction leads to mutagenic products such as 8-oxoguanine (5-8). DNA within cells is tightly packed and does not closely resemble oligonucleotides in solution. An examination of radical-cation hopping through DNA in loosely organized nucleosome core particles showed that histone binding does not affect the pattern and extent of oxidation (9). However, it is not known how the long-distance radical-cation migration that is observed in oligonucleotides is affected by conversion of the DNA to a well ordered structure. We began the systematic investigation of this question by examining the reactions of radical cations that were specifically introduced into DNA condensates.Multivalent cations like spermine or spermidine and proteins such as polylysine initiate DNA condensation (10-14). DNA condensates are nanometer-scale particles formed by the collapse of extended DNA chains into compact, ordered structures containing a small number of molecules (15, 16). These structures are recognized as models that are useful for studying gene packing in viruses, bacteria, and eukaryotic cells (17).We prepared condensates formed from the linearized pUC19 plasmid (which contains 2,686 bp) that had been ligated to an oligonucleotide containing a covalently linked anthraquinone (AQ) group (for photoinitiated introduction of a radical cation) and a series of regularly spaced GG steps (as traps for the radical cation) (Fig. 1) (18). Dynamic light-scattering results and examination by transmission electron microscopy (TEM) shows that the ligated DNA sample is converted into condensates by the addition of spermidine. The condensates were irradiated with UV light (t...

show abstract

Section: Resultsmentioning

confidence: 99%

Effect of condensate formation on long-distance radical cation migration in DNA

Das

Schuster

2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Pulse radiolysis experiments showed that 8-HO-dG ⅐ radicals generated by the addition of hydroxyl radicals to dG are strong reductants that are easily oxidized by weak oxidants such as methylviologen, Fe(CN) 6 3Ϫ , oxygen (27), and benzoquinone (56) resulting potentially in the formation of 8-oxodGuo. According to this mechanism, the O atom in 8-oxodGuo originates from H 2 18 O. Cadet and co-workers (54) showed that 8-oxodGuo derived from the oxidation of calf thymus DNA by excited riboflavin, a typical type I photodynamic agent, contains O atoms from H 2 18 O. In typical experiments with oxidation of calf thymus DNA by type I photosensitizers such as riboflavin, benzophenone, and menadione in the presence of oxygen, 8-oxoGua and Z lesions form in similar yields (57).…”

Section: Combination Of G(ϫh) ⅐ and O 2 Radicals; Electron Transfermentioning

confidence: 98%

Oxidative DNA Damage Associated with Combination of Guanine and Superoxide Radicals and Repair Mechanisms via Radical Trapping

Misiaszek

Crean

Joffe

et al. 2004

Journal of Biological Chemistry

207

250

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

“…Time-resolved spectroscopy reveals that the excited state of the quinone accepts an electron from a base in the DNA within 20 ps of excitation (21). The base radical cation (hole) can either recombine with the electron, be trapped by reaction with water and͞or oxygen, or migrate along the DNA helix to the lowest oxidation potential sites that serve as traps (22,23).We prepared a series of PNA oligomers with anthraquinone derivatives (AQ) covalently linked to internal positions. The ability of the quinone to photosensitize DNA damage by electron transfer when bound to the duplex by intercalation suggested it could serve a similar role in PNA-containing duplexes.…”

mentioning

confidence: 99%

Peptide nucleic acid–DNA duplexes: Long range hole migration from an internally linked anthraquinone

Armitage

Ly²,

Koch³

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The discovery that peptide nucleic acids (PNA) mimic DNA and RNA by forming complementary duplex structures following Watson-Crick base pairing rules opens fields in biochemistry, diagnostics, and medicine for exploration. Progress requires the development of modified PNA duplexes having unique and well defined properties. We find that anthraquinone groups bound to internal positions of a PNA oligomer intercalate in the PNA-DNA hybrid. Their irradiation with near-UV light leads to electron transfer and oxidative damage at remote GG doublets on the complementary DNA strand. This behavior mimics that observed in related DNA duplexes and provides the first evidence for long range electron (hole) transport in PNA-DNA hybrid. Analysis of the mechanism for electron transport supports hole hopping.Peptide nucleic acid (PNA) oligomers are DNA͞RNA analogs (see Fig. 1) in which the natural sugar-phosphate backbone is replaced by a synthetic peptide backbone (1). PNA oligomers that contain purine and pyrimidine nucleobases hybridize with complementary DNA and RNA strands to form right-handed, double-helical complexes according to the Watson-Crick rules of hydrogen bond-mediated base pair formation (2). Although much has been learned about the structural (3) and thermodynamic (4) factors involved in hybridization, little is known about the chemical reactivity of PNA͞DNA hybrids. It is crucial to understand how PNA͞DNA hybrids mimic the reactions and functions of duplex DNA. Of immediate importance for their application as clinical diagnostic agents is investigation of the conductivity of DNA and its PNA analogs (5, 6).DNA must balance the dual requirements of chemical stability and ease of transcription and replication (7). It is clear that DNA is far from inert toward a variety of different reactive species, particularly oxidizing agents. Oxidative damage to DNA produced by normal metabolism, deep-UV laser irradiation (8), gamma rays (9), or pulse radiolysis (10) accumulates at guanine residues, an effect attributed to one-dimensional migration of a radical cation (''hole'') along the DNA helix (11). Both the low oxidation potential and reactivity of the guanine radical cation contribute to the effectiveness of guanine as a trap for the migrating hole. Because guanine lesions may be the major cause of mutations (12), intense attention is focused on understanding the conductivity properties of DNA to elucidate the mechanisms by which migration of oxidative damage occurs (13). In this regard, the recent reports by Barton and coworkers are particularly important (14, 15). They describe a system consisting of a rhodium complex that is covalently linked to one end of a DNA duplex. Irradiation caused damage to the DNA more than 30 Å from where the complex was presumed to intercalate. This observation opens up exciting opportunities to study the factors that control hole migration in nucleic acids.Photosensitizers often react with nucleic acids by single electron transfer to oxidize a base. Recent findings reveal that the...

show abstract

Photosensitized formation of 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-hydroxy-2'-deoxyguanosine) in DNA by riboflavin: a nonsinglet oxygen-mediated reaction

Cited by 344 publications

References 0 publications

Effect of condensate formation on long-distance radical cation migration in DNA

Effect of condensate formation on long-distance radical cation migration in DNA

Oxidative DNA Damage Associated with Combination of Guanine and Superoxide Radicals and Repair Mechanisms via Radical Trapping

Peptide nucleic acid–DNA duplexes: Long range hole migration from an internally linked anthraquinone

Contact Info

Product

Resources

About