301
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Investigation on the Interactions of NiCR and NiCR-2H with DNA. Bioinorg Chem Appl 2010:619436. [PMID: 20671951 PMCID: PMC2910472 DOI: 10.1155/2010/619436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 04/06/2010] [Accepted: 05/05/2010] [Indexed: 01/21/2023] Open
Abstract
We report here a biophysical and biochemical approach to determine the differences in interactions of NiCR and NiCR-2H with DNA. Our goal is to determine whether such interactions are responsible for the recently observed differences in their cytotoxicity toward MCF-7 cancer cells. Viscosity measurement and fluorescence displacement titration indicated that both NiCR and NiCR-2H bind weakly to duplex DNA in the grooves. The coordination of NiCR-2H with the N-7 of 2'-deoxyguanosine 5'-monophosphate (5'-dGMP) is stronger than that of NiCR as determined by (1)H NMR. NiCR-2H, like NiCR, can selectively oxidize guanines present in distinctive DNA structures (e.g., bulges), and notably, NiCR-2H oxidizes guanines more efficiently than NiCR. In addition, UV and (1)H NMR studies revealed that NiCR is oxidized into NiCR-2H in the presence of KHSO(5) at low molar ratios with respect to NiCR (</=4).
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302
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Ding S, Kolbanovskiy A, Durandin A, Crean C, Shafirovich V, Broyde S, Geacintov NE. Absolute configurations of DNA lesions determined by comparisons of experimental ECD and ORD spectra with DFT calculations. Chirality 2010; 21 Suppl 1:E231-41. [PMID: 19937959 DOI: 10.1002/chir.20804] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The usefulness of modern density functional theory (DFT) methods is considered for establishing the absolute configurations of DNA lesions by comparisons of computed and experimentally measured optical rotatory dispersion (ORD) and electronic circular dichroism (ECD) spectra. Two rigid, structurally different DNA lesions (two spiroiminodihydantoin stereoisomers and four equine estrogen 4-hydoxyequilenin-DNA stereoisomeric adducts) have been investigated. In all cases, the signs and shapes of the computed ORD spectra reproduced the experimentally measured ORD spectra, although the magnitudes of the computed and experimental ORD values do not coincide exactly. The computed ECD spectra also reproduced the shapes of the experimental ECD spectra rather well, but are blue-shifted by 10-20 nm. Since the assignments of the absolute configurations of the DNA lesions studied based on computed and experimental ORD and ECD spectra are fully consistent with one another, the computational DFT method shows significant promise for determining the absolute configurations of DNA lesions. Establishing the stereochemistry of DNA lesions is highly useful for understanding their biological impact, especially when sufficient amounts of material are not available for other methods of structural characterization.
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Affiliation(s)
- Shuang Ding
- Department of Biology, New York University, New York, USA
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303
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Abstract
Oxidative damage to DNA has long been associated with aging and disease, with guanine serving as the primary target for oxidation owing to its low ionization potential. Emerging evidence points to a critical role for sequence context as a determinant of the guanine ionization potential and the associated chemical reactivity of the guanine, as well as the spectrum of damage products that arise from oxidation. Recent studies also suggest that the generally accepted model of oxidation hotspots in runs of guanine bases may not hold for biologically relevant oxidants. One of the primary methods used to address these important problems of sequence context utilizes gel electrophoresis to identify the location and quantity of base damage arising in model oligonucleotides. However, this approach has limited study to those agents that produce few strand breaks arising from deoxyribose oxidation, while ionizing radiation, Fenton chemistry and other biologically relevant oxidants produce sizeable proportions of both base and sugar damage. To this end, we have developed a universal method to quantify sequence context effects on nucleobase damage without interference by strand breaks from deoxyribose oxidation.
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304
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Gates KS. An overview of chemical processes that damage cellular DNA: spontaneous hydrolysis, alkylation, and reactions with radicals. Chem Res Toxicol 2010; 22:1747-60. [PMID: 19757819 DOI: 10.1021/tx900242k] [Citation(s) in RCA: 351] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The sequence of heterocyclic bases on the interior of the DNA double helix constitutes the genetic code that drives the operation of all living organisms. With this said, it is not surprising that chemical modification of cellular DNA can have profound biological consequences. Therefore, the organic chemistry of DNA damage is fundamentally important to diverse fields including medicinal chemistry, toxicology, and biotechnology. This review is designed to provide a brief overview of the common types of chemical reactions that lead to DNA damage under physiological conditions.
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Affiliation(s)
- Kent S Gates
- Departments of Chemistry and Biochemistry, University of Missouri-Columbia, 125 Chemistry Building, Columbia, Missouri 65211.
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305
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Kundu S, Brinkmeyer MK, Livingston AL, David SS. Adenine removal activity and bacterial complementation with the human MutY homologue (MUTYH) and Y165C, G382D, P391L and Q324R variants associated with colorectal cancer. DNA Repair (Amst) 2010; 8:1400-10. [PMID: 19836313 DOI: 10.1016/j.dnarep.2009.09.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 09/17/2009] [Accepted: 09/19/2009] [Indexed: 10/20/2022]
Abstract
MUTYH-associated polyposis (MAP) is the only inherited colorectal cancer syndrome that is associated with inherited biallelic mutations in a base excision repair gene. The MUTYH glycosylase plays an important role in preventing mutations associated with 8-oxoguanine (OG) by removing adenine residues that have been misincorporated opposite OG. MAP-associated mutations are present throughout MUTYH, with a large number coding for missense variations. To date the available information on the functional properties of MUTYH variants is conflicting. In this study, a kinetic analysis of the adenine glycosylase activity of MUTYH and several variants was undertaken using a correction for active fraction to control for differences due to overexpression and purification. Using these methods, the rate constants for steps involved in the adenine removal process were determined for the MAP variants Y165C, G382D, P391L and Q324R MUTYH. Under single-turnover conditions, the rate of adenine removal for these four variants was found to be 30-40% of WT MUTYH. In addition, the ability of MUTYH and the variants to suppress mutations and complement for the absence of MutY in Escherichia coli was assessed using rifampicin resistance assays. The presence of WT and Q324R MUTYH resulted in complete suppression of the mutation frequency, while G382D MUTYH showed reduced ability to suppress the mutation frequency. In contrast, the mutation frequency observed upon expression of P391L and Y165C MUTYH were similar to the controls, suggesting no activity toward preventing DNA mutations. Notably, though all variations studied herein resulted in similar reductions in adenine glycosylase activity, the effects in the bacterial complementation are quite different. This suggests that the consequences of a specific amino acid variation on overall repair in a cellular context may be magnified.
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Affiliation(s)
- Sucharita Kundu
- Department of Chemistry, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
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306
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Genereux JC, Boal AK, Barton JK. DNA-mediated charge transport in redox sensing and signaling. J Am Chem Soc 2010; 132:891-905. [PMID: 20047321 PMCID: PMC2902267 DOI: 10.1021/ja907669c] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The transport of charge through the DNA base-pair stack offers a route to carry out redox chemistry at a distance. Here we describe characteristics of this chemistry that have been elucidated and how this chemistry may be utilized within the cell. The shallow distance dependence associated with these redox reactions permits DNA-mediated signaling over long molecular distances in the genome and facilitates the activation of redox-sensitive transcription factors globally in response to oxidative stress. The long-range funneling of oxidative damage to sites of low oxidation potential in the genome also may provide a means of protection within the cell. Furthermore, the sensitivity of DNA charge transport to perturbations in base-pair stacking, as may arise with base lesions and mismatches, may be used as a route to scan the genome for damage as a first step in DNA repair. Thus, the ability of double-helical DNA in mediating redox chemistry at a distance provides a natural mechanism for redox sensing and signaling in the genome.
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Affiliation(s)
- Joseph C. Genereux
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125,
| | - Amie K. Boal
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125,
| | - Jacqueline K. Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125,
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307
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Pitié M, Pratviel G. Activation of DNA Carbon−Hydrogen Bonds by Metal Complexes. Chem Rev 2010; 110:1018-59. [DOI: 10.1021/cr900247m] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Marguerite Pitié
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France, and Université de Toulouse, Toulouse, France
| | - Geneviève Pratviel
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France, and Université de Toulouse, Toulouse, France
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308
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Kino K, Sugasawa K, Mizuno T, Bando T, Sugiyama H, Akita M, Miyazawa H, Hanaoka F. Eukaryotic DNA polymerases alpha, beta and epsilon incorporate guanine opposite 2,2,4-triamino-5(2H)-oxazolone. Chembiochem 2010; 10:2613-6. [PMID: 19780077 DOI: 10.1002/cbic.200900492] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Katsuhito Kino
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa 769-2193, Japan.
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309
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Kaloudis P, D’Angelantonio M, Guerra M, Spadafora M, Cismaş C, Gimisis T, Mulazzani QG, Chatgilialoglu C. Comparison of Isoelectronic 8-HO-G and 8-NH2-G Derivatives in Redox Processes. J Am Chem Soc 2009; 131:15895-902. [DOI: 10.1021/ja9065464] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Panagiotis Kaloudis
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy, and Department of Chemistry, University of Athens, 15771 Panepistimiopolis, Athens, Greece
| | - Mila D’Angelantonio
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy, and Department of Chemistry, University of Athens, 15771 Panepistimiopolis, Athens, Greece
| | - Maurizio Guerra
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy, and Department of Chemistry, University of Athens, 15771 Panepistimiopolis, Athens, Greece
| | - Marie Spadafora
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy, and Department of Chemistry, University of Athens, 15771 Panepistimiopolis, Athens, Greece
| | - Crina Cismaş
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy, and Department of Chemistry, University of Athens, 15771 Panepistimiopolis, Athens, Greece
| | - Thanasis Gimisis
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy, and Department of Chemistry, University of Athens, 15771 Panepistimiopolis, Athens, Greece
| | - Quinto G. Mulazzani
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy, and Department of Chemistry, University of Athens, 15771 Panepistimiopolis, Athens, Greece
| | - Chryssostomos Chatgilialoglu
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy, and Department of Chemistry, University of Athens, 15771 Panepistimiopolis, Athens, Greece
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310
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DNA damage and repair in a model of rat vascular injury. Clin Sci (Lond) 2009; 118:473-85. [PMID: 19804370 DOI: 10.1042/cs20090416] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/18/2009] [Accepted: 10/05/2009] [Indexed: 12/21/2022]
Abstract
Restenosis rate following vascular interventions still limits their long-term success. Oxidative stress plays a relevant role in this pathophysiological phenomenon, but less attention has been devoted to its effects on DNA damage and to the subsequent mechanisms of repair. We analysed in a model of arteriotomy-induced stenosis in rat carotids the time-dependent expression of DNA damage markers and of DNA repair genes, together with the assessment of proliferation and apoptosis indexes. The expression of the oxidative DNA damage marker 7,8-dihydro-8-oxo-2'-deoxyguanosine was increased at 3 and 7 days after arteriotomy, with immunostaining distributed in the injured vascular wall and in perivascular tissue. The expression of the DNA damage marker phospho-H2A.X was less relevant but increasing from 4 hrs to 7 days after arteriotomy, with immunostaining prevalently present in the adventitia and, to a lesser extent, in medial smooth muscle cells at the injury site. RT-PCR indicated a decrease of 8 out of 12 genes of the DNA repair machinery we selected from 4 hrs to 7 days after arteriotomy with the exception of increased Muyth and Slk genes (p<0.05). Western Blot revealed a decrease of p53 and catalase at 3 days after arteriotomy (p<0.05). A maximal 7% of BrdU-positive cells in endothelium and media occurred at 7 days after arteriotomy, while the apoptotic index peaked at 3 days after injury (p<0.05). Our results highlight a persistent DNA damage presumably related to a temporary decreased expression of the DNA repair machinery and of the antioxidant enzyme catalase, playing a role in stenosis progression.
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311
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Kaloudis P, Paris C, Vrantza D, Encinas S, Pérez-Ruiz R, Miranda MA, Gimisis T. Photolabile N-hydroxypyrid-2(1H)-one derivatives of guanine nucleosides: a new method for independent guanine radical generation. Org Biomol Chem 2009; 7:4965-72. [PMID: 19907788 DOI: 10.1039/b909138f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
One-electron oxidized guanine is an important reactive intermediate in the formation of oxidatively generated damage in DNA and a variety of methods have been utilized for the abstraction of a single electron from the guanine moiety. In this study, an alternative approach for the site specific, independent generation of the guanine radical, utilizing N-hydroxypyrid-2(1H)-one as a photolabile modifier of guanine, is proposed. Novel photolabile 6-[(1-oxido-2-pyridinyl)oxo]-6-deoxy- and 2',6-dideoxy-guanosine derivatives capable of generating the neutral guanine radical (G(-H)*) upon photolysis were synthesized and characterized. The generation of G(-H)* proceeds through homolysis of the N-O bond and was confirmed through continuous photolysis product analysis and trapping studies, as well as laser flash photolysis experiments.
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Affiliation(s)
- Panagiotis Kaloudis
- Organic Chemistry Laboratory, Department of Chemistry, University of Athens, Panepistimiopolis, 15771 Athens, Greece
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312
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Lokaj K, Meierjohann S, Schütz C, Teutschbein J, Schartl M, Sickmann A. Quantitative differential proteome analysis in an animal model for human melanoma. J Proteome Res 2009; 8:1818-27. [PMID: 19249851 DOI: 10.1021/pr800578a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In fish of the genus Xiphophorus, different grades of pigment cell lesions from nevi to melanoma can be gained by simple crossbreeding. With this model, one can easily access tissues of different malignancies from animals with highly identical genetic background. To find protein expression differences between healthy, benign and malignant tissues, we performed 2D PAGE and DIGE and found among regulated proteins antioxidant proteins that were overexpressed with increasing malignancy.
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Affiliation(s)
- Katrin Lokaj
- Rudolf-Virchow-Center, DFG-Research Center for Experimental Biomedicine, University of Wurzburg, Versbacher Str. 9, 97078 Wurzburg, Germany
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313
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Huang H, Imoto S, Greenberg MM. The mutagenicity of thymidine glycol in Escherichia coli is increased when it is part of a tandem lesion. Biochemistry 2009; 48:7833-41. [PMID: 19618962 DOI: 10.1021/bi900927d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tandem lesions are comprised of two contiguously damaged nucleotides. Tandem lesions make up the major family of reaction products generated from a pyrimidine nucleobase radical, which are formed in large amounts by ionizing radiation. One of these tandem lesions contains a thymidine glycol lesion flanked on its 5'-side by 2-deoxyribonolactone (LTg). The replication of this tandem lesion was investigated in Escherichia coli using single-stranded genomes. LTg is a much more potent replication block than thymidine glycol and is bypassed only under SOS-induced conditions. The adjacent thymidine glycol does not significantly affect nucleotide incorporation opposite 2-deoxyribonolactone in wild-type cells. In contrast, the misinsertion frequency opposite thymidine glycol, which is negligible in the absence of 2-deoxyribonolactone, increases to 10% in wild-type cells when LTg is flanked by a 3'-dG. Experiments in which the flanking nucleotides are varied and in cells lacking one of the SOS-induced bypass polymerases indicate that the mutations are due to a mechanism in which the primer misaligns prior to bypassing the lesion, which allows for an additional nucleotide to be incorporated across from the 3'-flanking nucleotide. Subsequent realignment and extension results in the observed mutations. DNA polymerases II and IV are responsible for misalignment induced mutations and compete with DNA polymerase V which reads through the tandem lesion. These experiments reveal that incorporation of the thymidine glycol into a tandem lesion indirectly induces increases in mutations by blocking replication, which enables the misalignment-realignment mechanism to compete with direct bypass by DNA polymerase V.
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Affiliation(s)
- Haidong Huang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
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314
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Park JH, Mangal D, Frey AJ, Harvey RG, Blair IA, Penning TM. Aryl hydrocarbon receptor facilitates DNA strand breaks and 8-oxo-2'-deoxyguanosine formation by the aldo-keto reductase product benzo[a]pyrene-7,8-dione. J Biol Chem 2009; 284:29725-34. [PMID: 19726680 DOI: 10.1074/jbc.m109.042143] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polycyclic aromatic hydrocarbon (PAH) o-quinones produced by aldo-keto reductases are ligands for the aryl hydrocarbon receptor (AhR) (Burczynski, M. E., and Penning, T. M. (2000) Cancer Res. 60, 908-915). They induce oxidative DNA lesions (reactive oxygen species-mediated DNA strand breaks and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dGuo) formation) in human lung cells. We tested whether the AhR enhances PAH o-quinone-mediated oxidative DNA damage by translocating these ligands to the nucleus. Using the single cell gel electrophoresis (comet) assay to detect DNA strand breaks in murine hepatoma Hepa1c1c7 cells and its AhR- and aryl hydrocarbon receptor nuclear translocator-deficient variants, benzo[a]pyrene-7,8-dione (B[a]P-7,8-dione) produced fewer DNA strand breaks in AhR-deficient cells compared with aryl hydrocarbon receptor nuclear translocator-deficient and wild type Hepa1c1c7 cells. Decreased DNA strand breaks were also observed in human bronchoalveolar H358 cells in which the AhR was silenced by siRNA. The antioxidant alpha-tocopherol and the iron chelator/antioxidant desferal decreased the formation of B[a]P-7,8-dione-mediated DNA strand breaks indicating that they were reactive oxygen species-dependent. By coupling the comet assay to 8-oxoguanine glycosylase (hOGG1), which excises 8-oxo-Gua, strand breaks dependent upon this lesion were measured. hOGG1 treatment produced more DNA single strand breaks in B[a]P-7,8-dione-treated Hepa cells and H358 cells than in its absence. The levels of hOGG1-dependent DNA strand breaks mediated by B[a]P-7,8-dione were lower in AhR-deficient Hepa and AhR knockdown H358 cells. The AhR antagonist alpha-naphthoflavone also attenuated B[a]P-7,8-dione-mediated DNA strand breaks. The decrease in 8-oxo-dGuo levels in AhR-deficient Hepa cells and AhR knockdown H358 cells was validated by immunoaffinity capture stable isotope dilution ([(15)N(5)]8-oxo-dGuo) liquid chromatography-electrospray ionization/multiple reaction monitoring/mass spectrometry. We conclude that the AhR shuttles PAH o-quinone genotoxins to the nucleus and enhances oxidative DNA damage.
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Affiliation(s)
- Jong-Heum Park
- Center of Excellence in Environmental Toxicology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6084, USA
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315
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Shukla PK, Mishra PC. Repair of O6-methylguanine to guanine by cysteine in the absence and presence of histidine and by cysteine thiolate anion: a quantum chemical study. Phys Chem Chem Phys 2009; 11:8191-202. [PMID: 19756275 DOI: 10.1039/b908295f] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
O6-methylguanine (O6mG) is known to be a potential mutagenic modification of guanine as it mispairs with thymine in DNA and causes GC to AT transversion mutation. It is experimentally known that O6mG can be repaired to guanine by the protein O6-alkylguanine-DNA alkyltransferase (AGT), a cysteine residue being the main active site. In the present work, the mechanisms of repair of cis-O6-methylguanine (O6mG) to guanine due to its reaction with cysteine in the absence and presence of histidine and with cysteine thiolate anion were investigated theoretically using the B3LYP hybrid functional of density functional theory and the second order Møller-Plesset perturbation (MP2) theory. Reactant, intermediate and product complexes as well as transition states involved in these reactions were fully optimized at the B3LYP/6-31 + G* level of theory in the gas phase. The solvent effect of water was treated using the polarizable continuum model (PCM). Single point energy calculations were performed at the B3LYP/AUG-cc-pVDZ and MP2/6-31 + G* levels of theory in the gas phase and aqueous media. It is found that cysteine alone can repair the cis-O6mG to guanine, but the involvement of histidine along with cysteine lowers down the barrier energy significantly. However, when cysteine thiolate anion is used in place of cysteine, the barrier energy is strongly reduced. These results broadly support the suggestions based on experimental studies.
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Affiliation(s)
- P K Shukla
- Department of Physics, Banaras Hindu University, Varanasi - 221005, India
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316
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Ye W, Sangaiah R, Degen DE, Gold A, Jayaraj K, Koshlap KM, Boysen G, Williams J, Tomer KB, Mocanu V, Dicheva N, Parker CE, Schaaper RM, Ball LM. Iminohydantoin lesion induced in DNA by peracids and other epoxidizing oxidants. J Am Chem Soc 2009; 131:6114-23. [PMID: 19354244 DOI: 10.1021/ja8090752] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The oxidation of guanine to 5-carboxamido-5-formamido-2-iminohydantoin (2-Ih) is shown to be a major transformation in the oxidation of the single-stranded DNA 5-mer d(TTGTT) by m-chloroperbenzoic acid (m-CPBA) and dimethyldioxirane (DMDO) as a model for peracid oxidants and in the oxidation of the 5-base pair duplex d[(TTGTT).(AACAA)] with DMDO. 2-Ih has not been reported as an oxidative lesion at the level of single/double-stranded DNA or at the nucleoside/nucleotide level. The lesion is stable to DNA digestion and chromatographic purification, suggesting that 2-Ih may be a stable biomarker in vivo. The oxidation products have been structurally characterized and the reaction mechanism has been probed by oxidation of the monomeric species dGuo, dGMP, and dGTP. DMDO selectively oxidizes the guanine moiety of dGuo, dGMP, and dGTP to 2-Ih, and both peracetic and m-chloroperbenzoic acids exhibit the same selectivity. The presence of the glycosidic bond results in the stereoselective induction of an asymmetric center at the spiro carbon to give a mixture of diastereomers, with each diastereomer in equilibrium with a minor conformer through rotation about the formamido C-N bond. Labeling studies with [(18)O(2)]-m-CPBA and H(2)(18)O to determine the source of the added oxygen atoms have established initial epoxidation of the guanine 4-5 bond with pyrimidine ring contraction by an acyl 1,2-migration of guanine carbonyl C6 to form a transient dehydrodeoxyspiroiminodihydantoin followed by hydrolytic ring-opening of the imidazolone ring. Consistent with the proposed mechanism, no 8-oxoguanine was detected as a product of the oxidations of the oligonucleotides or monomeric species mediated by DMDO or the peracids. The 2-Ih base thus appears to be a pathway-specific lesion generated by peracids and possibly other epoxidizing agents and holds promise as a potential biomarker.
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Affiliation(s)
- Wenjie Ye
- Department of Environmental Sciences and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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317
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Liu H, Llano J, Gauld JW. A DFT study of nucleobase dealkylation by the DNA repair enzyme AlkB. J Phys Chem B 2009; 113:4887-98. [PMID: 19338370 DOI: 10.1021/jp810715t] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidative dealkylation is a unique mechanistic pathway found in the alpha-ketoglutarate-Fe(II)-dependent AlkB family of enzymes to remove the alkylation damage to DNA bases and regenerate nucleobases to their native state. The B3LYP density functional combined with a self-consistent reaction field was used to explore the triplet, quintet, and septet spin-state potential energy surfaces of the multistep catalytic mechanism of AlkB. The mechanism was found to consist of four stages. First, binding of dioxygen to iron in the active-site complex occurs concerted with electron transfer, thereby yielding a ferric-superoxido species. Second, competing initiation for the activation of oxygen to generate the high-valent iron-oxygen intermediates (ferryl-oxo Fe(IV)O and ferric-oxyl Fe(III)O(*) species) was found to occur on the quintet and septet surfaces. Then, conformational reorientation of the activated iron-oxygen ligand was found to be nearly thermoneutral with a barrier of ca. 50 kJ mol(-1). The final stage is the oxidative dealkylation of the damaged nucleobase with the rate-controlling step being the abstraction of a hydrogen atom from the damaging methyl group by the ferryl-oxo ligand. For this step, the calculated barrier of 87.4 kJ mol(-1) is in good agreement with the experimental activation energy of ca. 83 kJ mol(-1) for the enzyme-catalyzed reaction.
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Affiliation(s)
- Haining Liu
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
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318
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Tiwari S, Mishra PC. A quantum chemical study of repair of O6-methylguanine to guanine by tyrosine: evaluation of the winged helix-turn-helix model. J Mol Model 2009; 15:1407-15. [PMID: 19421793 DOI: 10.1007/s00894-009-0499-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 04/16/2009] [Indexed: 11/24/2022]
Abstract
The winged helix-turn-helix model for the repair of O6-MeG to guanine involving the reaction of O6-MeG with a tyrosine residue of the protein O6-alkylguanine-DNA alkyltransferase (AGT) was examined by studying the reaction mechanism and barrier energies. Molecular geometries of the species and complexes involved in the reaction, i.e. the reactant, intermediate and product complexes as well as transition states, were optimized employing density functional theory in gas phase. It was followed by single point energy calculations using density functional theory along with a higher basis set and second order M(phi)ller-Plesset perturbation theory (MP2) along with two different basis sets in gas phase and aqueous media. For the solvation calculations in aqueous media, the integral equation formalism of the polarizable continuum model (IEF-PCM) was employed. Vibrational frequency analysis was performed for each optimized structure and genuineness of transition states was ensured by visualizing the vibrational modes. It is found that tyrosine can repair O6-MeG to guanine by a two-step reaction. The present results have been compared with those obtained considering the helix-turn-helix model where the repair reaction primarily involves cysteine and occurs in a single-step. It is concluded that the repair through tyrosine envisaged in the winged helix-turn-helix model would be less efficient than that through cysteine envisaged in the helix-turn-helix model.
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Affiliation(s)
- Saumya Tiwari
- Department of Physics, Banaras Hindu University, Varanasi, India
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319
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Dos Vultos T, Mestre O, Tonjum T, Gicquel B. DNA repair inMycobacterium tuberculosisrevisited. FEMS Microbiol Rev 2009; 33:471-87. [DOI: 10.1111/j.1574-6976.2009.00170.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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320
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Elevated mutation frequency in surviving populations of carbon-starved rpoS-deficient Pseudomonas putida is caused by reduced expression of superoxide dismutase and catalase. J Bacteriol 2009; 191:3604-14. [PMID: 19346306 DOI: 10.1128/jb.01803-08] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
RpoS is a bacterial sigma factor of RNA polymerase which is involved in the expression of a large number of genes to facilitate survival under starvation conditions and other stresses. The results of our study demonstrate that the frequency of emergence of base substitution mutants is significantly increased in long-term-starved populations of rpoS-deficient Pseudomonas putida cells. The increasing effect of the lack of RpoS on the mutation frequency became apparent in both a plasmid-based test system measuring Phe(+) reversion and a chromosomal rpoB system detecting rifampin-resistant mutants. The elevated mutation frequency coincided with the death of about 95% of the cells in a population of rpoS-deficient P. putida. Artificial overexpression of superoxide dismutase or catalase in the rpoS-deficient strain restored the survival of cells and resulted in a decline in the mutation frequency. This indicated that, compared to wild-type bacteria, rpoS-deficient cells are less protected against damage caused by reactive oxygen species. 7,8-Dihydro-8-oxoguanine (GO) is known to be one of the most stable and frequent base modifications caused by oxygen radical attack on DNA. However, the spectrum of base substitution mutations characterized in rpoS-deficient P. putida was different from that in bacteria lacking the GO repair system: it was broader and more similar to that identified in the wild-type strain. Interestingly, the formation of large deletions was also accompanied by a lack of RpoS. Thus, the accumulation of DNA damage other than GO elevates the frequency of mutation in these bacteria. It is known that oxidative damage of proteins and membrane components, but not that of DNA, is a major reason for the death of cells. Since the increased mutation frequency was associated with a decline in the viability of bacteria, we suppose that the elevation of the mutation frequency in the surviving population of carbon-starved rpoS-deficient P. putida may be caused both by oxidative damage of DNA and enzymes involved in DNA replication and repair fidelity.
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321
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Markus TZ, Daube SS, Naaman R, Fleming AM, Muller JG, Burrows CJ. Electronic structure of DNA--unique properties of 8-oxoguanosine. J Am Chem Soc 2009; 131:89-95. [PMID: 19128174 DOI: 10.1021/ja804177j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
8-Oxo-7,8-dihydroguanosine (8-oxoG) is among the most common forms of oxidative DNA damage found in human cells. The question of damage recognition by the repair machinery is a long standing one, and it is intriguing to suggest that the mechanism of efficiently locating damage within the entire genome might be related to modulations in the electronic properties of lesions compared to regular bases. Using laser-based methods combined with organizing various oligomers self-assembled monolayers on gold substrates, we show that indeed 8-oxoG has special electronic properties. By using oligomers containing 8-oxoG and guanine bases which were inserted in an all thymine sequences, we were able to determine the energy of the HOMO and LUMO states and the relative density of electronic states below the vacuum level. Specifically, it was found that when 8-oxoG is placed in the oligomer, the HOMO state is at higher energy than in the other oligomers studied. In contrast, the weakly mutagenic 8-oxo-7,8-dihydroadenosine (8-oxoA) has little or no effect on the electronic properties of DNA.
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Affiliation(s)
- Tal Z Markus
- Department of Chemical Physics, Chemical Research Support, Weizmann Institute, Rehovot 76100, Israel
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322
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A Reevaluation of the Ambident Reactivity of the Guanine Moiety Towards Hydroxyl Radicals. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200805372] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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323
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Chatgilialoglu C, D'Angelantonio M, Guerra M, Kaloudis P, Mulazzani Q. A Reevaluation of the Ambident Reactivity of the Guanine Moiety Towards Hydroxyl Radicals. Angew Chem Int Ed Engl 2009; 48:2214-7. [DOI: 10.1002/anie.200805372] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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324
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Agnihotri N, Mishra PC. Mutagenic Product Formation Due to Reaction of Guanine Radical Cation with Nitrogen Dioxide. J Phys Chem B 2009; 113:3129-38. [DOI: 10.1021/jp805942y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Neha Agnihotri
- Department of Physics, Banaras Hindu University, Varanasi - 221 005, India
| | - P. C. Mishra
- Department of Physics, Banaras Hindu University, Varanasi - 221 005, India
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325
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Crystal structure analysis of DNA lesion repair and tolerance mechanisms. Curr Opin Struct Biol 2009; 19:87-95. [DOI: 10.1016/j.sbi.2009.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 01/12/2009] [Accepted: 01/16/2009] [Indexed: 12/16/2022]
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326
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Nitric oxide and TNF-alpha trigger colonic inflammation and carcinogenesis in Helicobacter hepaticus-infected, Rag2-deficient mice. Proc Natl Acad Sci U S A 2009; 106:1027-32. [PMID: 19164562 DOI: 10.1073/pnas.0812347106] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Recombinase-activating gene-2-deficient (Rag2(-/-)) mice lacking functional lymphocytes provide a useful model of chronic inflammatory bowel disease-emulating events in human colon cancer. Infection of Rag2(-/-) mice with Helicobacter hepaticus led to accumulation of macrophages and neutrophils in the colon, a process temporally related to up-regulation of tissue inducible nitric oxide synthase (iNOS) expression at the site of infection and increased nitric oxide (NO) production, as evidenced by urinary excretion of nitrate. Progressive development of increasingly severe inflammation, hyperplasia, dysplasia, and cancer accompanied these changes. Concurrent administration of an iNOS inhibitor prevented NO production and abrogated epithelial pathology and inhibited the onset of cancer. The presence of Gr-1(+) neutrophils and elevated tumor necrosis factor-alpha (TNF-alpha) expression in colon were required for increased iNOS expression and cancer, whereas interleukin-10 (IL-10) down-regulated TNF-alpha and iNOS expression and suppressed cancer. Anti-inflammatory CD4(+) regulatory lymphocytes also down-regulated iNOS and reduced cancer formation. Collectively, these results confirm essential roles for inflammation, increased TNF-alpha expression, and elevated NO production in colon carcinogenesis.
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327
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Kell DB. Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases. BMC Med Genomics 2009; 2:2. [PMID: 19133145 PMCID: PMC2672098 DOI: 10.1186/1755-8794-2-2] [Citation(s) in RCA: 364] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Accepted: 01/08/2009] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. REVIEW We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here. CONCLUSION Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.
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Affiliation(s)
- Douglas B Kell
- School of Chemistry and Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.
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328
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Structural and biological impact of radical addition reactions with DNA nucleobases. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2009. [DOI: 10.1016/s0065-3160(08)00005-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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329
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Fenn D, Chi LM, Lam SL. Effect of hyperoxidized guanine on DNA primer-template structures: spiroiminodihydantoin leads to strand slippage. FEBS Lett 2008; 582:4169-75. [PMID: 19041867 DOI: 10.1016/j.febslet.2008.11.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2008] [Revised: 11/13/2008] [Accepted: 11/17/2008] [Indexed: 01/10/2023]
Abstract
Oxidation of guanine in DNA can lead to mutagenic lesions such as 7-hydro-8-oxoguanine (oG). Upon further oxidation, a more mutagenic lesion, spirominodihydantoin (Sp), can occur. In this study, nuclear magnetic resonance (NMR) investigations were performed to determine the structural features of DNA primer-template models with 5'-GG, 5'-G(oG), 5'-G(Sp) and 5'-T(Sp) templates, that mimic the situation in which the downstream G of the template has been oxidized to oG or hyperoxidized to Sp. Our results show that misalignment occurs only in the 5'-G(Sp) and 5'-T(Sp) templates, providing structural insights into the observed differences in mutagenicity of Sp and oG during DNA replication.
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Affiliation(s)
- Dickson Fenn
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
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330
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Morero NR, Argaraña CE. Pseudomonas aeruginosa deficient in 8-oxodeoxyguanine repair system shows a high frequency of resistance to ciprofloxacin. FEMS Microbiol Lett 2008; 290:217-26. [PMID: 19025574 DOI: 10.1111/j.1574-6968.2008.01411.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The 8-oxodeoxyguanine (8-oxodG) repair system participates in the prevention and correction of mutations generated by oxidative DNA damage in prokaryotes and eukaryotes. In this study, we report that Pseudomonas aeruginosa strains deficient in this repair mechanism by inactivation of the mutT, mutM and mutY genes generate a high frequency of cells resistant to the antibiotic ciprofloxacin. In the mutT strain, the increase in ciprofloxacin resistance achieved at threefold minimal inhibitory concentration was about 1600-fold over the wild-type (WT) level, similar to the frequency achieved by the mismatch repair-deficient mutS strain. Molecular analysis of WT, mutT and mutY clones resistant to ciprofloxacin indicated that the nfxB gene was mutated in the majority of the cases, while mutS-derived resistant clones were mainly mutated in gyrA and parC genes. Cell viability analysis after treatment with paraquat or hydrogen peroxide indicated that 8-oxodG repair-deficient strains were considerably more susceptible to oxidative stress than the parental strain. Finally, it is shown that the ciprofloxacin resistance frequency of WT and repair-deficient strains increased significantly after cell exposure to paraquat. Thus, oxidative stress is strongly implicated in the emergence of ciprofloxacin-resistant mutants in P. aeruginosa, and the 8-oxodG repair pathway plays an important role in the prevention of these mutations.
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Affiliation(s)
- Natalia R Morero
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
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331
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Maynard S, Schurman SH, Harboe C, de Souza-Pinto NC, Bohr VA. Base excision repair of oxidative DNA damage and association with cancer and aging. Carcinogenesis 2008; 30:2-10. [PMID: 18978338 DOI: 10.1093/carcin/bgn250] [Citation(s) in RCA: 429] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Aging has been associated with damage accumulation in the genome and with increased cancer incidence. Reactive oxygen species (ROS) are produced from endogenous sources, most notably the oxidative metabolism in the mitochondria, and from exogenous sources, such as ionizing radiation. ROS attack DNA readily, generating a variety of DNA lesions, such as oxidized bases and strand breaks. If not properly removed, DNA damage can be potentially devastating to normal cell physiology, leading to mutagenesis and/or cell death, especially in the case of cytotoxic lesions that block the progression of DNA/RNA polymerases. Damage-induced mutagenesis has been linked to various malignancies. The major mechanism that cells use to repair oxidative damage lesions, such as 8-hydroxyguanine, formamidopyrimidines, and 5-hydroxyuracil, is base excision repair (BER). The BER pathway in the nucleus is well elucidated. More recently, BER was shown to also exist in the mitochondria. Here, we review the association of BER of oxidative DNA damage with aging, cancer and other diseases.
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Affiliation(s)
- Scott Maynard
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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332
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Baute J, Depicker A. Base excision repair and its role in maintaining genome stability. Crit Rev Biochem Mol Biol 2008; 43:239-76. [PMID: 18756381 DOI: 10.1080/10409230802309905] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
For all living organisms, genome stability is important, but is also under constant threat because various environmental and endogenous damaging agents can modify the structural properties of DNA bases. As a defense, organisms have developed different DNA repair pathways. Base excision repair (BER) is the predominant pathway for coping with a broad range of small lesions resulting from oxidation, alkylation, and deamination, which modify individual bases without large effect on the double helix structure. As, in mammalian cells, this damage is estimated to account daily for 10(4) events per cell, the need for BER pathways is unquestionable. The damage-specific removal is carried out by a considerable group of enzymes, designated as DNA glycosylases. Each DNA glycosylase has its unique specificity and many of them are ubiquitous in microorganisms, mammals, and plants. Here, we review the importance of the BER pathway and we focus on the different roles of DNA glycosylases in various organisms.
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Affiliation(s)
- Joke Baute
- Department of Plant Systems Biology, Flanders Institute for Biotechnology, Gent, Belgium
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333
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Mueller H, Hopfinger M, Carell T. Synthesis of a stabilized version of the imidazolone DNA lesion. Chembiochem 2008; 9:1617-22. [PMID: 18506863 DOI: 10.1002/cbic.200700690] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Imidazolone (dIz) is an abundant, highly mutagenic, and rather unstable DNA lesion that can cause dG-->dC transversion mutations. dIz is generated in DNA by a variety of oxidative processes such as type I photooxidation. Herein we report the synthesis of a carbocyclic nucleoside analogue of dIz and of DNA containing this stabilized lesion analogue. The carbocyclic modification protects this lesion analogue from anomerization. As the repair of the lesion analogue by DNA glycosylases is not possible, this analogue should allow cocrystallization studies together with wild-type repair enzymes. Characterization of the lesion analogue was performed by using spectroscopic methods and enzymatic digestion experiments of the oligonucleotides.
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Affiliation(s)
- Heiko Mueller
- Department of Chemistry and Biochemistry, Ludwig-Maximilians-University, Butenandtstrasse 5-13, 81377 Munich, Germany
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334
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Cadet J, Douki T, Ravanat JL. Oxidatively generated damage to the guanine moiety of DNA: mechanistic aspects and formation in cells. Acc Chem Res 2008; 41:1075-83. [PMID: 18666785 DOI: 10.1021/ar700245e] [Citation(s) in RCA: 409] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nuclear DNA and other molecules in living systems are continuously exposed to endogenously generated oxygen species. Such species range from the unreactive superoxide radical (O2*-)the precursor of hydrogen peroxide (H2O2)to the highly reactive hydroxyl radical (*OH). Exogenous chemical and physical agents, such as ionizing radiation and the UVA component of solar light, can also oxidatively damage both the bases and the 2-deoxyribose moieties of cellular DNA. Over the last two decades, researchers have made major progress in understanding the oxidation degradation pathways of DNA that are most likely to occur from either oxidative metabolism or exposure to various exogenous agents. In the first part of this Account, we describe the mechanistic features of one-electron oxidation reactions of the guanine base in isolated DNA and related model compounds. These reactions illustrate the complexity of the various degradation pathways involved. Then, we briefly survey the analytical methods that can detect low amounts of oxidized bases and nucleosides in cells as they are formed. Recent data on the formation of oxidized guanine residues in cellular DNA following exposure to UVA light, ionizing radiation, and high-intensity UV pulses are also provided. We discuss these chemical reactions in the context of *OH radical, singlet oxygen, and two-quantum photoionization processes.
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Affiliation(s)
- Jean Cadet
- Laboratoire “Lésions des Acides Nucléiques”, SCIB-UMR-E n3 (CEA/UJF) Institut Nanosciences et Cryogénie, CEA/Grenoble, F-38054 Grenoble Cedex 9, France
- Department of Nuclear Medicine and Health Science, University of Sherbrooke, Quebec J1H 5N4, Canada
| | - Thierry Douki
- Laboratoire “Lésions des Acides Nucléiques”, SCIB-UMR-E n3 (CEA/UJF) Institut Nanosciences et Cryogénie, CEA/Grenoble, F-38054 Grenoble Cedex 9, France
| | - Jean-Luc Ravanat
- Laboratoire “Lésions des Acides Nucléiques”, SCIB-UMR-E n3 (CEA/UJF) Institut Nanosciences et Cryogénie, CEA/Grenoble, F-38054 Grenoble Cedex 9, France
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335
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Boussicault F, Robert M. Electron Transfer in DNA and in DNA-Related Biological Processes. Electrochemical Insights. Chem Rev 2008; 108:2622-45. [DOI: 10.1021/cr0680787] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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336
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Krishnamurthy N, Zhao X, Burrows CJ, David SS. Superior removal of hydantoin lesions relative to other oxidized bases by the human DNA glycosylase hNEIL1. Biochemistry 2008; 47:7137-46. [PMID: 18543945 DOI: 10.1021/bi800160s] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The DNA glycosylase hNEIL1 initiates the base excision repair (BER) of a diverse array of lesions, including ring-opened purines and saturated pyrimidines. Of these, the hydantoin lesions, guanidinohydantoin (Gh) and the two diastereomers of spiroiminodihydantoin (Sp1 and Sp2), have garnered much recent attention due to their unusual structures, high mutagenic potential, and detection in cells. In order to provide insight into the role of repair, the excision efficiency by hNEIL1 of these hydantoin lesions relative to other known substrates was determined. Most notably, quantitative examination of the substrate specificity with hNEIL1 revealed that the hydantoin lesions are excised much more efficiently (>100-fold faster) than the reported standard substrates thymine glycol (Tg) and 5-hydroxycytosine (5-OHC). Importantly, the glycosylase and beta,delta-lyase reactions are tightly coupled such that the rate of the lyase activity does not influence the observed substrate specificity. The activity of hNEIL1 is also influenced by the base pair partner of the lesion, with both Gh and Sp removal being more efficient when paired with T, G, or C than when paired with A. Notably, the most efficient removal is observed with the Gh or Sp paired in the unlikely physiological context with T; indeed, this may be a consequence of the unstable nature of base pairs with T. However, the facile removal via BER in promutagenic base pairs that are reasonably formed after replication (such as Gh.G) may be a factor that modulates the mutagenic profile of these lesions. In addition, hNEIL1 excises Sp1 faster than Sp2, indicating the enzyme can discriminate between the two diastereomers. This is the first time that a BER glycosylase has been shown to be able to preferentially excise one diastereomer of Sp. This may be a consequence of the architecture of the active site of hNEIL1 and the structural uniqueness of the Sp lesion. These results indicate that the hydantoin lesions are the best substrates identified thus far for hNEIL1 and suggest that repair of these lesions may be a critical function of the hNEIL1 enzyme in vivo.
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Affiliation(s)
- Nirmala Krishnamurthy
- Department of Chemistry, University of Utah, 315 South, 1400 East, Salt Lake City, Utah 84112, USA
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337
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Shukla PK, Mishra PC. Reactions of NO2Cl with Imidazole: A Model Study for the Corresponding Reactions of Guanine. J Phys Chem B 2008; 112:7925-36. [DOI: 10.1021/jp801093r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- P. K. Shukla
- Department of Physics, Banaras Hindu University, Varanasi-221005, India
| | - P. C. Mishra
- Department of Physics, Banaras Hindu University, Varanasi-221005, India
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338
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Oxidative stress impairs the repair of oxidative DNA base modifications in human skin fibroblasts and melanoma cells. DNA Repair (Amst) 2008; 7:912-21. [DOI: 10.1016/j.dnarep.2008.03.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 03/07/2008] [Accepted: 03/08/2008] [Indexed: 02/05/2023]
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339
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Slean MM, Panigrahi GB, Ranum LP, Pearson CE. Mutagenic roles of DNA "repair" proteins in antibody diversity and disease-associated trinucleotide repeat instability. DNA Repair (Amst) 2008; 7:1135-54. [PMID: 18485833 DOI: 10.1016/j.dnarep.2008.03.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
While DNA repair proteins are generally thought to maintain the integrity of the whole genome by correctly repairing mutagenic DNA intermediates, there are cases where DNA "repair" proteins are involved in causing mutations instead. For instance, somatic hypermutation (SHM) and class switch recombination (CSR) require the contribution of various DNA repair proteins, including UNG, MSH2 and MSH6 to mutate certain regions of immunoglobulin genes in order to generate antibodies of increased antigen affinity and altered effector functions. Another instance where "repair" proteins drive mutations is the instability of gene-specific trinucleotide repeats (TNR), the causative mutations of numerous diseases including Fragile X mental retardation syndrome (FRAXA), Huntington's disease (HD), myotonic dystrophy (DM1) and several spinocerebellar ataxias (SCAs) all of which arise via various modes of pathogenesis. These healthy and deleterious mutations that are induced by repair proteins are distinct from the genome-wide mutations that arise in the absence of repair proteins: they occur at specific loci, are sensitive to cis-elements (sequence context and/or epigenetic marks) and transcription, occur in specific tissues during distinct developmental windows, and are age-dependent. Here we review and compare the mutagenic role of DNA "repair" proteins in the processes of SHM, CSR and TNR instability.
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Affiliation(s)
- Meghan M Slean
- Program of Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1L7
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340
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Park JH, Gelhaus S, Vedantam S, Oliva AL, Batra A, Blair IA, Troxel AB, Field J, Penning TM. The pattern of p53 mutations caused by PAH o-quinones is driven by 8-oxo-dGuo formation while the spectrum of mutations is determined by biological selection for dominance. Chem Res Toxicol 2008; 21:1039-49. [PMID: 18489080 PMCID: PMC2671329 DOI: 10.1021/tx700404a] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PAHs (polycyclic aromatic hydrocarbons) are suspect lung cancer carcinogens that must be metabolically converted into DNA-reactive metabolites. P4501A1/P4501B1 plus epoxide hydrolase activate PAH to (+/-)- anti-benzo[ a]pyrene diol epoxide ((+/-)- anti-BPDE), which causes bulky DNA adducts. Alternatively, aldo-keto reductases (AKRs) convert intermediate PAH trans-dihydrodiols to o-quinones, which cause DNA damage by generating reactive oxygen species (ROS). In lung cancer, the types or pattern of mutations in p53 are predominantly G to T transversions. The locations of these mutations form a distinct spectrum characterized by single point mutations in a number of hotspots located in the DNA binding domain. One route to the G to T transversions is via oxidative DNA damage. An RP-HPLC-ECD assay was used to detect the formation of 8-oxo-dGuo in p53 cDNA exposed to representative quinones, BP-7,8-dione, BA-3,4-dione, and DMBA-3,4-dione under redox cycling conditions. Concurrently, a yeast reporter system was used to detect mutations in the same cDNA samples. Nanomolar concentrations of PAH o-quinones generated 8-oxo-dGuo (detected by HPLC-ECD) in a concentration dependent manner that correlated in a linear fashion with mutagenic frequency. By contrast, micromolar concentrations of (+/-)- anti-BPDE generated (+)- trans- anti-BPDE-N (2)-dGuo adducts (detected by stable-isotope dilution LC/MS methodology) in p53 cDNA that correlated in a linear fashion with mutagenic frequency, but no 8-oxo-dGuo was detected. Previous studies found that mutations observed with PAH o-quinones were predominately G to T transversions and those observed with (+/-)- anti-BPDE were predominately G to C transversions. However, mutations at guanine bases observed with either PAH-treatment occurred randomly throughout the DNA-binding domain of p53. Here, we find that when the mutants were screened for dominance, the dominant mutations clustered at or near hotspots primarily at the protein-DNA interface, whereas the recessive mutations are scattered throughout the DNA binding domain without resembling the spectra observed in cancer. These observations, if extended to mammalian cells, suggest that mutagenesis can drive the pattern of mutations but that biological selection for dominant mutations drives the spectrum of mutations observed in p53 in lung cancer.
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Affiliation(s)
- Jong-Heum Park
- Department of Pharmacology, Centers for Excellence in Environmental Toxicology and Cancer Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6084, USA
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341
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Lesion processing: high-fidelity versus lesion-bypass DNA polymerases. Trends Biochem Sci 2008; 33:209-19. [PMID: 18407502 DOI: 10.1016/j.tibs.2008.02.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 02/08/2008] [Accepted: 02/12/2008] [Indexed: 12/18/2022]
Abstract
When a high-fidelity DNA polymerase encounters certain DNA-damage sites, its progress can be stalled and one or more lesion-bypass polymerases are recruited to transit the lesion. Here, we consider two representative types of lesions: (i) 7,8-dihydro-8-oxoguanine (8-oxoG), a small, highly prevalent lesion caused by oxidative damage; and (ii) bulky lesions derived from the environmental pre-carcinogen benzo[a]pyrene, in the high-fidelity DNA polymerase Bacillus fragment (BF) from Bacillus stearothermophilus and in the lesion-bypass DNA polymerase IV (Dpo4) from Sulfolobus solfataricus. The tight fit of the BF polymerase around the nascent base pair contrasts with the more spacious, solvent-exposed active site of Dpo4, and these differences in architecture result in distinctions in their respective functions: one-step versus stepwise polymerase translocation, mutagenic versus accurate bypass of 8-oxoG, and polymerase stalling versus mutagenic bypass at bulky benzo[a]pyrene-derived lesions.
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342
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Weishar JL, McLaughlin CK, Baker M, Gabryelski W, Manderville RA. Oxidation of a Biomarker for Phenol Carcinogen Exposure: Expanding the Redox Chemistry of 2′-Deoxyguanosine. Org Lett 2008; 10:1839-42. [DOI: 10.1021/ol8004694] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jennifer L. Weishar
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | | | - Michael Baker
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Wojciech Gabryelski
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Richard A. Manderville
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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343
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Mourgues S, Trzcionka J, Vasseur JJ, Pratviel G, Meunier B. Incorporation of oxidized guanine nucleoside 5'-triphosphates in DNA with DNA polymerases and preparation of single-lesion carrying DNA. Biochemistry 2008; 47:4788-99. [PMID: 18370408 DOI: 10.1021/bi7022199] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We investigated the incorporation of oxidatively modified guanine residues in DNA using three DNA polymerases, Escherichia coli Kf exo+, Kf exo-, and Taq DNA polymerase. We prepared nucleoside 5'-triphosphates with modified bases (dN (ox)TP) including imidazolone associated with oxazolone (dIzTP/dZTP), dehydroguanidinohydantoin (dOGhTP), and oxaluric acid (dOxaTP). We showed that the single-nucleotide incorporation of these dN (ox)TP at the 3'-end of a primer DNA strand was possible opposite C or G for dIzTP/dZTP, opposite C for dOGhTP using the Klenow fragment, and opposite C for dOxaTP using Taq. The efficiency of these misincorporations was compared to that of the nucleoside 5'-triphosphate modified with the mutagenic guanine lesion 8-oxo-G opposite A or C as well as to that of the natural dNTPs. The reaction was found not competitive. However, the ability of Kf exo- to further copy the whole template DNA strand from the primer carrying one modified residue at the 3'-end proved to be easy and rapid. The two-step polymerization process consisting of the single-nucleotide extension followed by the full extension of a primer afforded a method for the preparation of tailored double-stranded DNA oligonucleotides carrying a single modified base at a precise site on any sequence. This very rapid method allowed the incorporation of unique residues in DNA that were not available before due to their unstable character.
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Affiliation(s)
- Sophie Mourgues
- Laboratoire de Chimie de Coordination du CNRS, 205 Route de Narbonne, Toulouse Cedex 4, France
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344
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Shukla PK, Mishra PC. Catalytic Involvement of CO2 in the Mutagenesis Caused by Reactions of ONOO- with Guanine. J Phys Chem B 2008; 112:4779-89. [DOI: 10.1021/jp710418b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- P. K. Shukla
- Department of Physics, Banaras Hindu University, Varanasi 221 005, India
| | - P. C. Mishra
- Department of Physics, Banaras Hindu University, Varanasi 221 005, India
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345
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Munk BH, Burrows CJ, Schlegel HB. An exploration of mechanisms for the transformation of 8-oxoguanine to guanidinohydantoin and spiroiminodihydantoin by density functional theory. J Am Chem Soc 2008; 130:5245-56. [PMID: 18355018 DOI: 10.1021/ja7104448] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The potential energy surface for formation of 2-amino-5-hydroxy-7,9-dihydropurine-6,8-dione (5-OH-OG), guanidinohydantoin (Gh) and spiroiminodihydantoin (Sp) from 8-oxoguanine (8-oxoG) has been mapped out using B3LYP density functional theory, the aug-cc-pVTZ and 6-31+G(d,p) basis sets and the IEF-polarizable continuum model (PCM) solvation model. Three pathways for formation of 5-OH-OG from 8-oxoG were evaluated: (A) stepwise loss of two electrons and two protons to form the quinonoid intermediate 2-amino-7,9-dihydro-purine-6,8-dione (8-oxoG(ox)) followed by hydration; (B) stepwise loss of two electrons and one proton and net addition of hydroxide, in which the key step is nucleophilic addition to the 8-oxoG radical cation; and (C) stepwise loss of one electron and one proton and addition of hydroxyl radical to the 8-oxoG radical cation. The data suggest that all three pathways are energetically feasible mechanisms for the formation of 5-OH-OG, however, Pathway A may be kinetically favored over Pathway B. Although lower in energy, Pathway C may be of limited biological significance since it depends on the local concentration of hydroxyl radical. Pathways for hydrolysis and decarboxylation of 5-OH-OG to form Gh via either a carboxylic acid or substituted carbamic acid intermediate have been evaluated with the result that cleavage of the N1-C6 bond is clearly favored over that of the C5-C6 bond. Formation of Sp from 5-OH-OG via stepwise proton transfer and acyl migration or ring opening followed by proton transfer and ring closure have also been explored and suggest that deprotonation of the hydroxyl group facilitates a 1,2 acyl shift. Results of the calculations are consistent with experimental studies showing dependence of the Gh/Sp product ratio on pH. Under neutral and basic conditions, the data predict that formation of Sp is kinetically favored over the pathways for formation of Gh. Under acidic conditions, Gh is predicted to be the kinetically favored product.
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Affiliation(s)
- Barbara H Munk
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
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346
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Lee YA, Durandin A, Dedon PC, Geacintov NE, Shafirovich V. Oxidation of guanine in G, GG, and GGG sequence contexts by aromatic pyrenyl radical cations and carbonate radical anions: relationship between kinetics and distribution of alkali-labile lesions. J Phys Chem B 2008; 112:1834-44. [PMID: 18211057 DOI: 10.1021/jp076777x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Oxidatively generated DNA damage induced by the aromatic radical cation of the pyrene derivative 7,8,9,10-tetrahydroxytetrahydrobenzo[a]pyrene (BPT), and by carbonate radicals anions, was monitored from the initial one-electron transfer, or hole injection step, to the formation of hot alkali-labile chemical end-products monitored by gel electrophoresis. The fractions of BPT molecules bound to double-stranded 20-35-mer oligonucleotides with noncontiguous guanines G and grouped as contiguous GG and GGG sequences were determined by a fluorescence quenching method. Utilizing intense nanosecond 355 nm Nd:YAG laser pulses, the DNA-bound BPT molecules were photoionized to BPT*+ radicals by a consecutive two-photon ionization mechanism. The BPT*+ radicals thus generated within the duplexes selectively oxidize guanine by intraduplex electron-transfer reactions, and the rate constants of these reactions follow the trend 5'-..GGG.. > 5'-..GG.. > 5'-..G... In the case of CO3*- radicals, the oxidation of guanine occurs by intermolecular collision pathways, and the bimolecular rate constants are independent of base sequence context. However, the distributions of the end-products generated by CO3*- radicals, as well as by BPT*+, are base sequence context-dependent and are greater than those in isolated guanines at the 5'-G in 5'-...GG... sequences, and the first two 5'- guanines in the 5'-..GGG sequences. These results help to clarify the conditions that lead to a similar or different base sequence dependence of the initial hole injection step and the final distribution of oxidized, alkali-labile guanine products. In the case of the intermolecular one-electron oxidant CO3*-, the rate constant of hole injection is similar for contiguous and isolated guanines, but the subsequent equilibration of holes by hopping favors trapping and product formation at contiguous guanines, and the sequence dependence of these two phenomena are not correlated. In contrast, in the case of the DNA-bound oxidant BPT*+, the hole injection rate constants, as well as hole equilibration, exhibit a similar dependence on base sequence context, and are thus correlated to one another.
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Affiliation(s)
- Young Ae Lee
- Chemistry Department, New York University, New York, NY 10003-5180, USA
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347
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Abbaspour A, Noori A. Electrochemical studies on the oxidation of guanine and adenine at cyclodextrin modified electrodes. Analyst 2008; 133:1664-72. [DOI: 10.1039/b806920d] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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348
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Delaney JC, Essigmann JM. Biological properties of single chemical-DNA adducts: a twenty year perspective. Chem Res Toxicol 2008; 21:232-52. [PMID: 18072751 PMCID: PMC2821157 DOI: 10.1021/tx700292a] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The genome and its nucleotide precursor pool are under sustained attack by radiation, reactive oxygen and nitrogen species, chemical carcinogens, hydrolytic reactions, and certain drugs. As a result, a large and heterogeneous population of damaged nucleotides forms in all cells. Some of the lesions are repaired, but for those that remain, there can be serious biological consequences. For example, lesions that form in DNA can lead to altered gene expression, mutation, and death. This perspective examines systems developed over the past 20 years to study the biological properties of single DNA lesions.
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Affiliation(s)
- James C. Delaney
- Departments of Chemistry and Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
| | - John M. Essigmann
- Departments of Chemistry and Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
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349
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dos Santos PE, Egito LCM, de Medeiros SRB, Agnez-Lima LF. Genotoxicity induced by Eugenia caryophyllata infusion. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:439-444. [PMID: 18306091 DOI: 10.1080/15287390701839232] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Several therapeutic properties have been described for Eugenia caryophyllata (clove). In the present study the infusion of E. caryophyllata was evaluated in a series of bacterial and cell-free assays in order to determine genotoxic potential. Negative results were obtained in the SOS chromotest and in the Salmonella reversion assay using strains TA97a, TA98, TA100, and TA102. However, in a forward mutagenesis assay an increase in mutagenesis and high cytotoxicity was observed with the CC104 mutMmutY strain, suggesting that oxidative DNA damage occurred. The treatment of plasmid with clove infusion showed that DNA strand breaks and sites recognized by formamidopyrimidine-DNA-glycosylase (FPG/MutM) were generated. Data suggest that the occurrence of oxidative DNA damage, with low mutagenic potential, may also be involved in the cytotoxicity attributed to clove infusion.
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Affiliation(s)
- Patrícia Estevam dos Santos
- Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, Brazil
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350
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Krishnamurthy N, Haraguchi K, Greenberg MM, David SS. Efficient removal of formamidopyrimidines by 8-oxoguanine glycosylases. Biochemistry 2007; 47:1043-50. [PMID: 18154319 DOI: 10.1021/bi701619u] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Under conditions of oxidative stress, the formamidopyrimidine lesions (FapyG and FapyA) are formed in competition with the corresponding 8-oxopurines (OG and OA) from a common intermediate. In order to reveal features of the repair of these lesions, and the potential contribution of repair in mitigating or exacerbating the mutagenic properties of Fapy lesions, their excision by three glycosylases, Fpg, hOGG1 and Ntg1, was examined in various base pair contexts under single-turnover conditions. FapyG was removed at least as efficiently as OG by all three glycosylases. In addition, the rates of removal of FapyG by Fpg and hOGG1 were influenced by their base pair partner, with preference for removal when base paired with the correct Watson-Crick partner C. With the FapyA lesion, Fpg and Ntg1 catalyze its removal more readily than OG opposite all four natural bases. In contrast, the removal of FapyA by hOGG1 was not as robust as FapyG or OG, and was only significant when the lesion was paired with C. The discrimination by the various glycosylases with respect to the opposing base was highly dependent on the identity of the lesion. OG induced the greatest selectivity against its removal when part of a promutagenic base pair. The superb activity of the various OG glycosylases toward removal of FapyG and FapyA in vitro suggests that these enzymes may act upon these oxidized lesions in vivo. The differences in the activity of the various glycosylases for removal of FapyG and FapyA compared to OG in nonmutagenic versus promutagenic base pair contexts may serve to alter the mutagenic profiles of these lesions in vivo.
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Affiliation(s)
- Nirmala Krishnamurthy
- Department of Chemistry, University of Utah, 315 South, 1400 East, Salt Lake City, Utah 84112, USA
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