1
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Berger FD, Sturla SJ, Kung RW, Montina T, Wetmore SD, Manderville RA. Conformational Preference and Fluorescence Response of a C-Linked C8-Biphenyl-Guanine Lesion in the NarI Mutational Hotspot: Evidence for Enhanced Syn Adduct Formation. Chem Res Toxicol 2017; 31:37-47. [DOI: 10.1021/acs.chemrestox.7b00266] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Florence D. Berger
- Department
of Health Sciences and Technology, Institute of Food, Nutrition, and
Health, ETH Zürich, 8092 Zürich, Switzerland
| | - Shana J. Sturla
- Department
of Health Sciences and Technology, Institute of Food, Nutrition, and
Health, ETH Zürich, 8092 Zürich, Switzerland
| | - Ryan W. Kung
- Department
of Chemistry and Biochemistry, and the Canadian Centre for Research
in Advanced Fluorine Technologies, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Tony Montina
- Department
of Chemistry and Biochemistry, and the Canadian Centre for Research
in Advanced Fluorine Technologies, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Stacey D. Wetmore
- Department
of Chemistry and Biochemistry, and the Canadian Centre for Research
in Advanced Fluorine Technologies, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Richard A. Manderville
- Departments
of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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2
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Sproviero M, Verwey AMR, Witham AA, Manderville RA, Sharma P, Wetmore SD. Enhancing Bulge Stabilization through Linear Extension of C8-Aryl-Guanine Adducts to Promote Polymerase Blockage or Strand Realignment to Produce a C:C Mismatch. Chem Res Toxicol 2015. [PMID: 26225720 DOI: 10.1021/acs.chemrestox.5b00233] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Aryl radicals can react at the C8-site of 2'-deoxyguanosine (dG) to produce DNA adducts with a C8-C linkage (denoted C-linked). Such adducts are structurally distinct from those possessing a flexible amine (N-linked) or ether (O-linked) linkage, which separates the C8-aryl moiety from the guanine nucleobase. In the current study, two model C-linked C8-dG adducts, namely, C8-benzo[b]thienyl-dG ([BTh]G) and C8-(pyren-1-yl)-dG ([Py]G), were incorporated into the NarI (12mer, NarI(12) and 22mer, NarI(22)) hotspot sequence for frameshift mutations in bacteria. For the first time, C-linked C8-dG adducts are shown to stabilize the -2 deletion duplex within the NarI sequence. Primer-elongation assays employing Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4) demonstrates the influence of C8-aryl ring size and shape in promoting Dpo4 blockage or strand realignment to produce a C:C mismatch downstream of the adduct site. Molecular dynamics simulations of the -2 deletion duplex suggest that both anti and syn adduct structures are energetically accessible. These findings provide a rationale for describing the biochemical outcome induced by C-linked C8-dG adducts when processed by Dpo4.
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Affiliation(s)
- Michael Sproviero
- †Department of Chemistry and Toxicology, University of Guelph, Guelph, ON Canada N1G 2W1
| | - Anne M R Verwey
- †Department of Chemistry and Toxicology, University of Guelph, Guelph, ON Canada N1G 2W1
| | - Aaron A Witham
- †Department of Chemistry and Toxicology, University of Guelph, Guelph, ON Canada N1G 2W1
| | - Richard A Manderville
- †Department of Chemistry and Toxicology, University of Guelph, Guelph, ON Canada N1G 2W1
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3
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Witham AA, Verwey AMR, Sproviero M, Manderville RA, Sharma P, Wetmore SD. Chlorine functionalization of a model phenolic C8-guanine adduct increases conformational rigidity and blocks extension by a Y-family DNA polymerase. Chem Res Toxicol 2015; 28:1346-56. [PMID: 26004422 DOI: 10.1021/acs.chemrestox.5b00143] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Certain phenoxyl radicals can attach covalently to the C8-site of 2'-deoxyguanosine (dG) to afford oxygen-linked C8-dG adducts. Such O-linked adducts can be chemically synthesized through a nucleophilic displacement reaction between a phenolate and a suitably protected 8-Br-dG derivative. This permits the generation of model O-linked C8-dG adducts on scales suitable for insertion into oligonucleotide substrates using solid-phase DNA synthesis. Variation of the C8-aryl moiety provides an opportunity to derive structure-activity relationships on adduct conformation in duplex DNA and replication bypass by DNA polymerases. In the current study, the influence of chlorine C8-dG functionalization on in vitro DNA replication by Klenow fragment exo(-) (Kf(-)) and the Y-family polymerase (Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4)) has been determined. Model O-linked C8-dG adducts derived from the pentachlorophenoxyl radical ([PCP]G) and 2,4,6-trichlorophenoxyl radical ([TCP]G) were inserted into the reiterated G3-position of the NarI sequence (12-mer, NarI(12); and 22-mer, NarI(22)), which is a known hotspot for frameshift mutations mediated by N-linked polycyclic C8-dG adducts in bacterial mutagenesis. Within the NarI(12) duplex, the unsubstituted C8-phenoxy-dG ([PhO]G) adduct adopts a minimally perturbed B-form helix. Chlorination of [PhO]G to afford [PCP]G does not significantly change the adduct conformation within the NarI(12) duplex, as predicted by molecular dynamics simulations. However, when using NarI(22) for DNA synthesis in vitro, the chlorinated [PCP]G and [TCP]G lesions significantly block DNA replication by Kf(-) and Dpo4, whereas [PhO]G is readily bypassed. These findings highlight the impact that chlorine substituents impart to bulky C8-dG lesions.
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Affiliation(s)
- Aaron A Witham
- †Departments of Chemistry and Toxicology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Anne M R Verwey
- †Departments of Chemistry and Toxicology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Michael Sproviero
- †Departments of Chemistry and Toxicology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Richard A Manderville
- †Departments of Chemistry and Toxicology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Purshotam Sharma
- ‡Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Stacey D Wetmore
- ‡Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
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4
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Sproviero M, Verwey AMR, Rankin KM, Witham AA, Soldatov DV, Manderville RA, Fekry MI, Sturla SJ, Sharma P, Wetmore SD. Structural and biochemical impact of C8-aryl-guanine adducts within the NarI recognition DNA sequence: influence of aryl ring size on targeted and semi-targeted mutagenicity. Nucleic Acids Res 2014; 42:13405-21. [PMID: 25361967 PMCID: PMC4245952 DOI: 10.1093/nar/gku1093] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Chemical mutagens with an aromatic ring system may be enzymatically transformed to afford aryl radical species that preferentially react at the C8-site of 2′-deoxyguanosine (dG). The resulting carbon-linked C8-aryl-dG adduct possesses altered biophysical and genetic coding properties compared to the precursor nucleoside. Described herein are structural and in vitro mutagenicity studies of a series of fluorescent C8-aryl-dG analogues that differ in aryl ring size and are representative of authentic DNA adducts. These structural mimics have been inserted into a hotspot sequence for frameshift mutations, namely, the reiterated G3-position of the NarI sequence within 12mer (NarI(12)) and 22mer (NarI(22)) oligonucleotides. In the NarI(12) duplexes, the C8-aryl-dG adducts display a preference for adopting an anti-conformation opposite C, despite the strong syn preference of the free nucleoside. Using the NarI(22) sequence as a template for DNA synthesis in vitro, mutagenicity of the C8-aryl-dG adducts was assayed with representative high-fidelity replicative versus lesion bypass Y-family DNA polymerases, namely, Escherichia coli pol I Klenow fragment exo− (Kf−) and Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4). Our experiments provide a basis for a model involving a two-base slippage and subsequent realignment process to relate the miscoding properties of C-linked C8-aryl-dG adducts with their chemical structures.
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Affiliation(s)
- Michael Sproviero
- Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Anne M R Verwey
- Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Katherine M Rankin
- Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Aaron A Witham
- Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Dmitriy V Soldatov
- Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Richard A Manderville
- Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Mostafa I Fekry
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zürich, 8032 Zürich, Switzerland Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini, Cairo 11562, Egypt
| | - Shana J Sturla
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zürich, 8032 Zürich, Switzerland
| | - Purshotam Sharma
- Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, AB, Canada, T1K 3M4
| | - Stacey D Wetmore
- Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1 Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zürich, 8032 Zürich, Switzerland Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini, Cairo 11562, Egypt Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, AB, Canada, T1K 3M4
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5
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Kuska MS, Witham AA, Sproviero M, Manderville RA, Majdi Yazdi M, Sharma P, Wetmore SD. Structural Influence of C8-Phenoxy-Guanine in the NarI Recognition DNA Sequence. Chem Res Toxicol 2013; 26:1397-408. [DOI: 10.1021/tx400252g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Michael S. Kuska
- Departments
of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Aaron A. Witham
- Departments
of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Michael Sproviero
- 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
| | - Mohadeseh Majdi Yazdi
- Department
of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Purshotam Sharma
- Department
of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Stacey D. Wetmore
- Department
of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
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6
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Mu H, Kropachev K, Wang L, Zhang L, Kolbanovskiy A, Kolbanovskiy M, Geacintov NE, Broyde S. Nucleotide excision repair of 2-acetylaminofluorene- and 2-aminofluorene-(C8)-guanine adducts: molecular dynamics simulations elucidate how lesion structure and base sequence context impact repair efficiencies. Nucleic Acids Res 2012; 40:9675-90. [PMID: 22904073 PMCID: PMC3479214 DOI: 10.1093/nar/gks788] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nucleotide excision repair (NER) efficiencies of DNA lesions can vary by orders of magnitude, for reasons that remain unclear. An example is the pair of N-(2′-deoxyguanosin-8-yl)-2-aminofluorene (dG-C8-AF) and N-(2′-deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-C8-AAF) adducts that differ by a single acetyl group. The NER efficiencies in human HeLa cell extracts of these lesions are significantly different when placed at G1, G2 or G3 in the duplex sequence (5′-CTCG1G2CG3CCATC-3′) containing the NarI mutational hot spot. Furthermore, the dG-C8-AAF adduct is a better substrate of NER than dG-C8-AF in all three NarI sequence contexts. The conformations of each of these adducts were investigated by Molecular dynamics (MD) simulation methods. In the base-displaced conformational family, the greater repair susceptibility of dG-C8-AAF in all sequences stems from steric hindrance effects of the acetyl group which significantly diminish the adduct-base stabilizing van der Waals stacking interactions relative to the dG-C8-AF case. Base sequence context effects for each adduct are caused by differences in helix untwisting and minor groove opening that are derived from the differences in stacking patterns. Overall, the greater NER efficiencies are correlated with greater extents of base sequence-dependent local untwisting and minor groove opening together with weaker stacking interactions.
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Affiliation(s)
- Hong Mu
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
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7
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Jain V, Hilton B, Patnaik S, Zou Y, Chiarelli MP, Cho BP. Conformational and thermodynamic properties modulate the nucleotide excision repair of 2-aminofluorene and 2-acetylaminofluorene dG adducts in the NarI sequence. Nucleic Acids Res 2012; 40:3939-51. [PMID: 22241773 PMCID: PMC3351159 DOI: 10.1093/nar/gkr1307] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nucleotide excision repair (NER) is a major repair pathway that recognizes and corrects various lesions in cellular DNA. We hypothesize that damage recognition is an initial step in NER that senses conformational anomalies in the DNA caused by lesions. We prepared three DNA duplexes containing the carcinogen adduct N-(2'-deoxyguanosin-8-yl)-7-fluoro-2-acetylaminofluorene (FAAF) at G(1), G(2) or G(3) of NarI sequence (5'-CCG(1)G(2)CG(3)CC-3'). Our (19)F-NMR/ICD results showed that FAAF at G(1) and G(3) prefer syn S- and W-conformers, whereas anti B-conformer was predominant for G(2). We found that the repair of FAAF occurs in a conformation-specific manner, i.e. the highly S/W-conformeric G(3) and -G(1) duplexes incised more efficiently than the B-type G(2) duplex (G(3)∼G(1)> G(2)). The melting and thermodynamic data indicate that the S- and W-conformers produce greater DNA distortion and thermodynamic destabilization. The N-deacetylated N-(2'-deoxyguanosin-8-yl)-7-fluoro-2-aminofluorene (FAF) adducts in the same NarI sequence are repaired 2- to 3-fold less than FAAF: however, the incision efficiency was in order of G(2)∼G(1)> G(3), a reverse trend of the FAAF case. We have envisioned the so-called N-acetyl factor as it could raise conformational barriers of FAAF versus FAF. The present results provide valuable conformational insight into the sequence-dependent UvrABC incisions of the bulky aminofluorene DNA adducts.
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Affiliation(s)
- Vipin Jain
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA
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8
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Millen AL, Kamenz BL, Leavens FMV, Manderville RA, Wetmore SD. Conformational flexibility of C8-phenoxylguanine adducts in deoxydinucleoside monophosphates. J Phys Chem B 2011; 115:12993-3002. [PMID: 21942470 DOI: 10.1021/jp2057332] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
M06-2X/6-31G(d,p) is used to calculate the structure of all natural deoxydinucleoside monophosphates with G in the 5' or 3' position, the anti or syn conformation, and each natural (A, C, G, T) base in the corresponding flanking position. When the ortho or para C8-phenoxyl-2'-deoxyguanosine (C8-phenoxyl-dG) adduct replaces G in each model, there is little change in the relative base-base orientation or backbone conformation. However, the orientation of the C8-phenoxyl group can be characterized according to the position (5' versus 3'), conformation (anti versus syn), and isomer (ortho versus para) of damage. Although the degree of coplanarity between the phenoxyl ring and G base in the ortho adduct is highly affected by the sequence since the hydroxyl group can interact with neighboring bases, the para adduct generally does not exhibit discrete interactions with flanking bases. For both adducts, steric clashes between the phenoxyl group and the backbone or flanking base destabilize the anti conformation preferred by the natural nucleotide and thereby result in a clear preference for the syn conformation regardless of the sequence or position. This contrasts the conclusions drawn from smaller (nucleoside, nucleotide) models previously used in the literature, which stresses the importance of using models that address the steric constraints present due to the surrounding environment. Since replication errors for other C8-dG bulky adducts have been linked to a preference for the syn conformation, our findings provide insight into the possible mutagenicity of phenolic adducts.
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Affiliation(s)
- Andrea L Millen
- Department of Chemistry, University of Lethbridge, Lethbridge, Alberta, Canada
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9
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Müller B, Shen WZ, Sanz Miguel PJ, Albertí FM, van der Wijst T, Noguera M, Rodríguez-Santiago L, Sodupe M, Lippert B. PtII Coordination to N1 of 9-Methylguanine: Why it Facilitates Binding of Additional Metal Ions to the Purine Ring. Chemistry 2011; 17:9970-83. [DOI: 10.1002/chem.201101148] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Indexed: 11/09/2022]
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10
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Patnaik S, Cho BP. Structures of 2-acetylaminofluorene modified DNA revisited: insight into conformational heterogeneity. Chem Res Toxicol 2010; 23:1650-2. [PMID: 20954689 DOI: 10.1021/tx100341u] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Despite the extensive data on dG-AAF, the major DNA adduct derived from the model carcinogen 2-acetylaminofluorene, little is known with respect to its solution structures. Here, we provide NMR/CD evidence for three conformers of dG-AAF in duplex DNA: major groove B-type (B), base-displaced stacked (S), and minor groove wedge (W). The S/B/W-conformational heterogeneities were found to be sensitive to the nature of the flanking DNA sequence contexts and pH.
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Affiliation(s)
- Satyakam Patnaik
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, USA
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11
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Jain N, Meneni S, Jain V, Cho BP. Influence of flanking sequence context on the conformational flexibility of aminofluorene-modified dG adduct in dA mismatch DNA duplexes. Nucleic Acids Res 2009; 37:1628-37. [PMID: 19151371 PMCID: PMC2655675 DOI: 10.1093/nar/gkn1063] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
When positioned opposite to a dA in a DNA duplex, the prototype arylamine-DNA adduct [N-(2'-deoxyguanosin-yl)-7-fluoro-2-aminofluorene (FAF)] adopts the so-called 'wedge' (W) conformation, in which the carcinogen resides in the minor groove of the duplex. All 16 FAF-modified 12-mer NG*N/NAN dA mismatch duplexes (G* = FAF, N = G, A, C, T) exhibited strongly positive induced circular dichroism in the 290-360 nm range (ICD(290-360 nm)), which supports the W conformation. The ICD(290-360 nm) intensities were the greatest for duplexes with a 3'-flanking T. The AG*N duplex series showed little adduct-induced destabilization. An exception was the AG*T duplex, which displayed two well-resolved signals in the (19)F NMR spectra. This was presumably due to a strong lesion-destabilizing effect of the 3'-T. The flanking T effect was substantiated further by findings with the TG*T duplex, which exhibited greater lesion flexibility and nucleotide excision repair recognition. Adduct conformational heterogeneity decreased in order of TG*T > AG*T > CG*T > AG*A > AG*G > AG*C. The dramatic flanking T effect on W-conformeric duplexes is consistent with the strong dependence of the ICD(290-360) on both temperature and salt concentration and could be extended to the arylamine food mutagens that are biologically relevant in humans.
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Affiliation(s)
- Nidhi Jain
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
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12
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Meneni S, Liang F, Cho BP. Examination of the long-range effects of aminofluorene-induced conformational heterogeneity and its relevance to the mechanism of translesional DNA synthesis. J Mol Biol 2006; 366:1387-400. [PMID: 17217958 PMCID: PMC1850230 DOI: 10.1016/j.jmb.2006.12.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 12/06/2006] [Accepted: 12/12/2006] [Indexed: 10/23/2022]
Abstract
Adduct-induced conformational heterogeneity complicates the understanding of how DNA adducts exert mutation. A case in point is the N-deacetylated AF lesion [N-(2'-deoxyguanosin-8-yl)-2-aminofluorene], the major adduct derived from the strong liver carcinogen N-acetyl-2-aminofluorene. Three conformational families have been previously characterized and are dependent on the positioning of the aminofluorene rings: B is in the "B-DNA" major groove, S is "stacked" into the helix with base-displacement, and W is "wedged" into the minor groove. Here, we conducted (19)F NMR, CD, T(m), and modeling experiments at various primer positions with respect to a template modified by a fluorine tagged AF-adduct (FAF). In the first set, the FAF-G was paired with C and in the second set it was paired with A. The FAF-G:C oligonucleotides were found to preferentially adopt the B or S-conformers while the FAF-G:A mismatch ones preferred the B and W-conformers. The conformational preferences of both series were dependent on temperature and complementary strand length; the largest differences in conformation were displayed at lower temperatures. The CD and T(m) results are in general agreement with the NMR data. Molecular modeling indicated that the aminofluorene moiety in the minor groove of the W-conformer would impose a steric clash with the tight-packing amino acid residues on the DNA binding area of the Bacillus fragment (BF), a replicative DNA polymerase. In the case of the B-type conformer, the carcinogenic moiety resides in the solvent-exposed major groove throughout the replication/translocation process. The present dynamic NMR results, combined with previous primer extension kinetic data by Miller & Grollman, support a model in which adduct-induced conformational heterogeneities at positions remote from the replication fork affect polymerase function through a long-range DNA-protein interaction.
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Affiliation(s)
| | | | - Bongsup P. Cho
- *Address correspondence to: Bongsup P. Cho, Dept. of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 41 Lower College Road, Kingston, Rhode Island 02881, Tel. 401-874-5024; Fax. 401-874-5766;
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13
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Liang F, Meneni S, Cho BP. Induced circular dichroism characteristics as conformational probes for carcinogenic aminofluorene-DNA adducts. Chem Res Toxicol 2006; 19:1040-3. [PMID: 16918242 DOI: 10.1021/tx0601253] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report novel induced circular dichroism (ICD) characteristics for probing the conformational heterogeneity induced by the arylamine carcinogen 2-aminofluorene, namely, B type (B), stacked (S), and wedged (W) conformers. CD experiments were conducted with five different aminofluorene-modified DNA duplexes (I-V). An intense positive ICD was observed for the W conformeric I in the 290-360 nm range (ICD(290)(-)(360nm)). This was in contrast to the negative ICD(290)(-)(360nm) exhibited by the mostly B conformeric V (17% S/83% B). Duplex IV, which adopts an approximately equal mixture of S (53%) and B (47%), exhibited low ellipticities along the baseline. The magnitude of the positive ICD for I was significantly greater than that observed for II (70% S/30% B). While the ICD(290)(-)(360nm) of the W conformeric III showed no changes in intensity with increasing temperature from 10 to 35 degrees C, dramatic changes were observed for I across the same temperature range. Dynamic (19)F NMR results revealed that I exists in an 85:15 mixture of W and S/B conformers. The dramatic intensity changes observed for I are consistent with the presence of a W/B heterogeneity because of its susceptibility to result in a large difference on the magnitude of the ICD(290)(-)(360nm). In conclusion, the sign and magnitude of the ICD(290)(-)(360)(nm) are sensitive conformational markers for studying arylamine-induced conformational heterogeneity. The temperature-dependent ICD(290)(-)(360nm) data, coupled with (19)F NMR spectroscopy, provide valuable information about conformational distribution and dynamics, which are important factors that affect mutational outcomes.
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Affiliation(s)
- Fengting Liang
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 41 Lower College Road, Kingston, Rhode Island 02881, USA
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14
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Structural characterization of N-acetyl-2-aminofluorene (AAF) adducts to guanine and deoxyguanosine via a molecular mechanics, semi-empirical, and density functional theory cascade. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2004.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Wang L, Hingerty BE, Shapiro R, Broyde S. Structural and stereoisomer effects of model estrogen quinone-derived DNA adducts: N6-(2-hydroxyestron-6(alpha,beta)-yl)-2'-deoxyadenosine and N2-(2-hydroxyestron-6(alpha,beta)-yl)-2'-deoxyguanosine. Chem Res Toxicol 2004; 17:311-24. [PMID: 15025501 DOI: 10.1021/tx034218l] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
An extensive conformational analysis has been carried out for two diastereoisomeric pairs of model estrogen quinone-derived DNA adducts, N6-(2-hydroxyestron-6(alpha,beta)-yl)-2'-deoxyadenosine (2-OHE1-6(alpha,beta)-N6-dA) and N2-(2-hydroxyestron-6(alpha,beta)-yl)-2'-deoxyguanosine (2-OHE1-6(alpha,beta)-N2-dG), in a B-DNA duplex and at a primer-template junction in a pol alpha family DNA polymerase. In vitro primer extension studies in pol alpha [Terashima, I., et al. (1998) Biochemistry 37, 13807-13815] have shown that the adenine adducts can incorporate dT, together with a small proportion of the incorrect base dC opposite the lesion, and they block less strongly than the guanine adducts. We have carried out conformational searches with energy minimization for four DNA duplexes containing 2-OHE1-6alpha-N6-dA, 2-OHE1-6beta-N6-dA, 2-OHE1-6alpha-N2-dG, or 2-OHE1-6beta-N2-dG. Our searches revealed that the four-ring nonplanar 2-hydroxyestrone (2-OHE1) moiety strongly prefers to reside in the major groove of the adenine adducts or the minor groove of the guanine adducts in a B-DNA duplex, with stereochemistry-dependent orientational differences in each case. No low energy conformations involving intercalation of the 2-OHE1 moiety were located in the searches. This stems from the largely nonplanar, nonaromatic nature of the 2-OHE1 ring system and implies that the proclivity for such bulky, nonplanar adducts to reside at the DNA helix exterior is a plausible conformational feature of other structurally similar estrogen quinone-derived DNA adducts, independent of base sequence context. In addition, the adenine adduct isomers, located in the major groove, manifest serious disturbance to the Watson-Crick base pairs at and near the lesion site, suggesting repair susceptibility. Possible structures of these adducts in a pol alpha family polymerase were also investigated through molecular modeling. The results rationalized the experimental in vitro primer extension studies. In addition, poor accommodation of the beta-stereoisomers within the polymerase was noted, suggesting that these stereoisomers would be more prone to cause blockage. Stereochemistry-dependent differences in adduct orientation could be expected to produce different biochemical effects, as has been observed in adducts derived from polycyclic aromatic hydrocarbons.
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Affiliation(s)
- Lihua Wang
- Biology Department and Chemistry Department, New York University, New York, New York 10003, USA
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16
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Besson M, Mihalek CL. Total energy of deoxyguanosine bonded to N-2-acetylaminofluorene by the semi-empirical modified-neglect of differential diatomic overlap method. Mutat Res 2001; 473:211-7. [PMID: 11166038 DOI: 10.1016/s0027-5107(00)00151-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We have computed the total energy surface as a function of two important torsion angles of the carcinogen N-2-acetylaminofluorene (AAF) bonded to the carbon C8 of deoxyguanosine using the semi-empirical quantum mechanical method, MNDO. One global minimum and one local minimum are found separated by an appreciable barrier. The equilibrium geometries show the rearrangement of AAF and the base consistent with experimental observations of previous investigators.
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Affiliation(s)
- M Besson
- Department of Physics, Villanova University, Villanova, PA 19085, USA.
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17
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Roy D, Hingerty BE, Shapiro R, Broyde S. A slipped replication intermediate model is stabilized by the syn orientation of N-2-aminofluorene- and N-2-(acetyl)aminofluorene-modified guanine at a mutational hotspot. Chem Res Toxicol 1998; 11:1301-11. [PMID: 9815190 DOI: 10.1021/tx980106w] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Escherichia coli NarI restriction enzyme recognition site 5'G1G2C3G4C5C63' is a mutational hotspot for -2 deletions in E. coli plasmid pBR322, resulting in the sequence 5'GGCC3' when G4 is modified by the aromatic amine N-2-(acetyl)aminofluorene (AAF) [Burnouf, D., Koehl, P., and Fuchs, R. P. P. (1995) Proc. Natl. Acad. Sci. U.S.A. 86, 4147-4151] even though each G shows similar reactivity [Fuchs, R. P. P. (1984) J. Mol. Biol. 177, 173-180]. Modification at G4 by the related aromatic amine 2-aminofluorene (AF), which lacks the acetyl group of AAF, can also cause -2 deletions, but at a lower frequency [Bichara, M., and Fuchs, R. P. P. (1985) J. Mol. Biol. 183, 341-351]. A specific mechanism has been proposed to explain the double-base frameshifts in the NarI sequence in which the GC deletion results from a slipped mutagenic intermediate formed during replication [Schaaper, B. M., Koffel-Schwartz, N., and Fuchs, R. P. P. (1990) Carcinogenesis 11, 1087-1095]. We address the following key questions in this study. Why does AAF modification dramatically increase the mutagenicity at the NarI G4 position, and why does AAF enhance the mutagenicity more than AF? We studied two intermediates which model replication at one arm of a fork, using a fragment of DNA modified by AF or AAF at G4 in the NarI sequence: Intermediate I can be converted into intermediate II by misalignment. Elongation of intermediate I leads to error-free translesion synthesis, while elongation of intermediate II leads to a -2 frameshift mutation. Minimized potential energy calculations were carried out using the molecular mechanics program DUPLEX to investigate the conformations of the AF and AAF adducts at G4 in these two intermediates. We find that the slipped mutagenic intermediate is quite stable relative to its normally extended counterpart in the presence of AF and AAF in an abnormal syn orientation of the damaged base. An enhanced probability of elongation from a stable slipped structure rather than a properly aligned one would favor increased -2 frameshift mutations. Furthermore, AAF-modified DNA has a greater tendency to adopt the syn orientation than AF because of its greater bulk, which could explain its greater propensity to cause -2 deletions in the NarI sequence.
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Affiliation(s)
- D Roy
- Biology Department, New York University, New York, New York 10003-5181, USA
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Beland FA, Melchior WB, Mourato LL, Santos MA, Marques MM. Arylamine-DNA adduct conformation in relation to mutagenesis. Mutat Res 1997; 376:13-9. [PMID: 9202733 DOI: 10.1016/s0027-5107(97)00020-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A considerable body of evidence has indicated that local conformational alterations induced by DNA adducts may provide the molecular basis for differences in mutational specificities exhibited by structurally similar adducts. To elucidate the relationships between adduct structure and mutation induction, the ability of several single-ring arylamines present in tobacco smoke (i.e., methylanilines, dimethylanilines, and ethylanilines) to form DNA adducts was investigated. In all cases, the major adducts were C8-substituted deoxyguanosine derivatives, which is consistent with what has been observed with more carcinogenic arylamines, such as 2-aminofluorene and 4-aminobiphenyl. Spectroscopic and theoretical data on the adducts indicated conformational differences depending upon the location of the alkyl substituents. Adducts containing alkyl groups ortho to the amino function (e.g., 2-methylaniline) had a greater percentage of syn conformers about the glycosyl bond than those not bearing such groups. Arylamines with ortho alkyl substituents tend to be more mutagenic and tumorigenic than analogues not containing an ortho alkyl substituent. This increase in biological activity may be due in part to the greater propensity of ortho alkylated adducts to adopt a syn conformation.
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Affiliation(s)
- F A Beland
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA.
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19
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Mao B, Vyas RR, Hingerty BE, Broyde S, Basu AK, Patel DJ. Solution conformation of the N-(deoxyguanosin-8-yl)-1-aminopyrene ([AP]dG) adduct opposite dC in a DNA duplex. Biochemistry 1996; 35:12659-70. [PMID: 8841109 DOI: 10.1021/bi961078o] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Combined NMR-molecular mechanics computational studies were undertaken on the C8-deoxyguanosine adduct formed by the carcinogen 1-nitropyrene embedded in the d(C5-[AP]G6-C7).d(G16-C17-G18) sequence context in a 11-mer duplex, with dC opposite the modified deoxyguanosine. The exchangeable and nonexchangeable protons of the aminopyrene moiety and the nucleic acid were assigned following analysis of two-dimensional NMR data sets in H2O and D2O solution. There was a general broadening of several proton resonances for the three nucleotide d(G16-C17-G18) segment positioned opposite the [AP]dG6 lesion site resulting in weaker NOEs involving these protons in the adduct duplex. The solution conformation of the [AP]dG.dC 11-mer duplex has been determined by incorporating intramolecular and intermolecular proton-proton distances defined by upper and lower bounds deduced from NOESY spectra as restraints in molecular mechanics computations in torsion angle space. The aminopyrene ring of [AP]dG6 is intercalated into the DNA helix between intact Watson-Crick dC5.dG18 and dC7.dG16 base pairs. The modified deoxyguanosine ring of [AP]dG6 is displaced into the major groove and stacks with the major groove edge of dC5 in the adduct duplex. Both carbon and proton chemical shift data for the sugar resonances of the modified deoxyguanosine residue are consistent with a syn glycosidic torsion angle for the [AP]dG6 residue. The dC17 base on the partner strand is displaced from the center of the helix toward the major groove as a consequence of the aminopyrene ring intercalation into the helix. This base-displaced intercalative structure of the [AP]dG.dC 11-mer duplex exhibits several unusually shifted proton resonances which can be accounted for by the ring current contributions of the deoxyguanosinyl and pyrenyl rings of the [AP]dG6 adduct. In summary, intercalation of the aminopyrene moiety is accompanied by displacement of both [AP]dG6 and the partner dC17 into the major groove in the [AP]dG.dC 11-mer duplex.
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Affiliation(s)
- B Mao
- Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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20
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Cosman M, Hingerty BE, Luneva N, Amin S, Geacintov NE, Broyde S, Patel DJ. Solution conformation of the (-)-cis-anti-benzo[a]pyrenyl-dG adduct opposite dC in a DNA duplex: intercalation of the covalently attached BP ring into the helix with base displacement of the modified deoxyguanosine into the major groove. Biochemistry 1996; 35:9850-63. [PMID: 8703959 DOI: 10.1021/bi9605346] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This paper reports on the combined NMR-molecular mechanics computational studies of the solution structure of the (-)-cis-anti-[BP]dG adduct positioned opposite dC in the sequence context d(C1- C2-A3-T4-C5-[BP]G6-C7-T8-A9-C10-C11).d(G12-G13-T14- A15-G16-C17-G18-A19-T20- G21-G22) duplex [designated (-)-cis-anti-[BP]dG.dC 11-mer duplex]. This adduct is derived from cis addition at C10 of (-)-anti-7(S),8(R)-dihydroxy-9(R),10(S)-epoxy-7,8,9,10- tetrahydrobenzo[a]pyrene [(-)-anti-BPDE] to the N2 position of dG6 in this duplex sequence. The exchangeable and nonexchangeable protons of the benzo[a]pyrenyl moiety and nucleic acid of the major conformation were assigned following analysis of two-dimensional NMR data sets in H2O and D2O solution. There was a general broadening of proton resonances for a three-nucleotide segment centered about the lesion site which resulted in a tentative assignment for the sugar protons of the C7 residue in the spectrum of the adduct duplex. The solution conformation of the major conformation of the (-)-cis-anti-[BP]dG.dC 11-mer duplex has been determined by incorporating DNA-DNA and intermolecular BP-DNA proton-proton distances defined by lower and upper bounds deduced from NOESY data sets as restraints in molecular mechanics computations in torsion angle space. The results establish that the covalently attached benzo[a]pyrenyl ring intercalates between intact Watson-Crick dC5.dG18 and dC7.dG16 base pairs. The modified deoxyguanosine [BP]-dG6 and its partner cytosine dC17 are looped out of the helix into the major groove. The purine ring of the [BP]dG6 residue is directed toward the 5'-end of the modified strand and stacks over the major groove edge of its 5'-side neighbor dC5 residue. The solution structure of the (-)-cis-anti-[BP]dG.dC 11-mer duplex is compared with those of the stereoisomeric (+)-trans-anti-[BP]dG [Cosman, M., et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 1914-1918], (-)-trans-anti-[BP]dG [de los Santos, C., et al. (1992) Biochemistry 31, 5245-5252], and (+)-cis-anti-[BP]dG [Cosman, M., et al. (1993a) Biochemistry 32, 4146-4155] adducts positioned opposite dC in the same duplex sequence context. A key finding is that the long axes of the intercalated benzo[a]pyrenyl rings in the solution structures of the (+)- and (-)- cis-anti-[BP]dG.dC 11-mer duplexes are oriented in opposite directions with the benzylic ring directed toward the minor groove in the (+)-cis isomer and toward the major groove in the (-)-cis isomer. In addition, a comparison is also made with the solution structure of the (+)-trans-anti-[BP]dG adduct opposite a deletion site [Cosman, M., et al. (1994a) Biochemistry 33, 11507-11517] since this adduct duplex displays several conformational features in common with the structure of the (-)-cis-anti-[BP]dG.dC 11-mer duplex. The structures of both duplex adducts exhibit intercalation of the covalently attached ligand into the helix and displacement of the modified deoxyguanosine into the major groove. Studies of the biological activities of stereochemically defined BP-DNA adducts and the comparison of the solution structure of the (-)-cis-anti-[BP]dG.dC 11-mer duplex with its stereoisomeric counterparts should lead to new insights into the relationships between defined helical distortions and mutagenic specificity and activity.
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Affiliation(s)
- M Cosman
- Cellular Biochemistry and Biophysics Program, Memorial Sloan Kettering Cancer Center, New York, New York 10021, USA
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21
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Marques MM, Mourato LL, Santos MA, Beland FA. Synthesis, characterization, and conformational analysis of DNA adducts from methylated anilines present in tobacco smoke. Chem Res Toxicol 1996; 9:99-108. [PMID: 8924623 DOI: 10.1021/tx950044z] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The ability of a series of aromatic amines present in tobacco smoke (2-, 3-, and 4-methylaniline, 2,3- and 2,4-dimethylaniline) to bind to DNA has been investigated by reacting N-(acyloxy)arylamines with dG, dG nucleotides, and DNA. The predominant products from reactions with dG and the nucleotides were characterized as N-(deoxyguanosin-8-yl)arylamines by spectroscopic and HPLC methods. HPLC and spectroscopic analyses of the modified DNA indicated the same adducts. Analyses of the 1H and 13C NMR spectra suggested that the adducts containing a methyl substituent ortho to the arylamine nitrogen had a higher percentage of syn conformers. This observation was supported by theoretical simulation studies that indicated substantial percentages of low energy syn conformers, increasing with the substitution pattern in the order para < meta < ortho < ortho,para < ortho,meta. The results demonstrate that, although single-ring arylamines are considered weak carcinogens, their electrophilic N-acetoxy derivatives, which are plausible metabolic intermediates, react with DNA to yield covalent adducts structurally identical to those derived from carcinogenic polyarylamines, such as 2-aminofluorene and 4-aminobiphenyl. Furthermore, the conformational perturbation induced in DNA by the formation of the monoarylamine-DNA adducts, especially those with an ortho substituent, may contribute to the biological activities of these compounds.
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Affiliation(s)
- M M Marques
- Centro de Química Estrutural, Instituto Superior Técnico, Lisboa, Portugal
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22
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Heflich RH, Neft RE. Genetic toxicity of 2-acetylaminofluorene, 2-aminofluorene and some of their metabolites and model metabolites. Mutat Res 1994; 318:73-114. [PMID: 7521935 DOI: 10.1016/0165-1110(94)90025-6] [Citation(s) in RCA: 174] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
2-Acetylaminofluorene and 2-aminofluorene are among the most intensively studied of all chemical mutagens and carcinogens. Fundamental research findings concerning the metabolism of 2-acetylaminofluorene to electrophilic derivatives, the interaction of these derivatives with DNA, and the carcinogenic and mutagenic responses that are associated with the resulting DNA damage have formed the foundation upon which much of genetic toxicity testing is based. The parent compounds and their proximate and ultimate mutagenic and carcinogenic derivatives have been evaluated in a variety of prokaryotic and eukaryotic assays for mutagenesis and DNA damage. The reactive derivatives are active in virtually all systems, while 2-acetylaminofluorene and 2-aminofluorene are active in most systems that provide adequate metabolic activation. Knowledge of the structures of the DNA adducts formed by 2-acetylaminofluorene and 2-aminofluorene, the effects of the adducts on DNA conformation and synthesis, adduct distribution in tissues, cells and DNA, and adduct repair have been used to develop hypotheses to understand the genotoxic and carcinogenic effects of these compounds. Molecular analysis of mutations produced in cell-free, bacterial, in vitro mammalian, and intact animal systems have recently been used to extend these hypotheses.
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Affiliation(s)
- R H Heflich
- Division of Genetic Toxicology, National Center for Toxicological Research, Jefferson, AR 72079
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23
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Garcia A, Lambert IB, Fuchs RP. DNA adduct-induced stabilization of slipped frameshift intermediates within repetitive sequences: implications for mutagenesis. Proc Natl Acad Sci U S A 1993; 90:5989-93. [PMID: 8327472 PMCID: PMC46852 DOI: 10.1073/pnas.90.13.5989] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Chemical carcinogens such as the aromatic amide 2-acetylaminofluorene (AAF) are known to induce -1 frameshift mutation hotspots at repetitive sequences. This mutagenesis pathway was suggested to involve slipped intermediates formed during replication. To investigate the stability and structure of such intermediates we have constructed DNA duplexes containing single AAF adducts within a run of three guanine residues. The strand complementary to that bearing the AAF adducts contained either the wild-type sequence (homoduplexes) or lacked one cytosine directly opposite the run of guanines containing the AAF adduct and thus modeled the putative slipped mutagenic intermediates (SMIs). The melting temperature of AAF-modified homoduplexes or the unmodified SMI was reduced by approximately 10 degrees C relative to the unmodified homoduplex. Surprisingly, AAF adducts stabilized the SMIs as evidenced by an increase in melting temperature to a level approaching that of the unmodified homoduplex. The chemical probes hydroxylamine and bromoacetaldehyde were strongly reactive toward cytosine residues opposite the adduct in AAF-modified homoduplexes, indicating adduct-induced denaturation. In contrast, no cytosine reactivities were observed in the AAF-modified SMIs, suggesting that the two cytosines were paired with unmodified guanines. Use of diethyl pyrocarbonate to probe the guanine residues showed that all three guanines in the unmodified SMI adopted a transient single-stranded state which was delocalized along the repetitive sequence. However, when an AAF adduct was present, reduced diethyl pyrocarbonate reactivity at guanines adjacent to the adduct in AAF-modified SMIs reflected localization of the bulge to the adducted base. Our results suggest that AAF exerts a local denaturing and destabilizing effect within the homoduplex which is alleviated by the formation of a bulge. The stabilization by the AAF adduct of the SMIs may contribute to the dramatic increase in -1 frameshift mutation frequency induced by AAF adducts in repetitive sequences.
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Affiliation(s)
- A Garcia
- U.P.R. no 9003 de Cancérogenèse et de Mutagenèse Moléculaire et Structurale, Centre National de la Recherche Scientifique, Strasbourg, France
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24
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Covalent carcinogenic guanine-modified DNA lesions: solution structures of adducts and crosslinks. Curr Opin Struct Biol 1992. [DOI: 10.1016/0959-440x(92)90224-u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Belguise-Valladier P, Fuchs RP. Strong sequence-dependent polymorphism in adduct-induced DNA structure: analysis of single N-2-acetylaminofluorene residues bound within the NarI mutation hot spot. Biochemistry 1991; 30:10091-100. [PMID: 1931941 DOI: 10.1021/bi00106a005] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have used a set of chemical probes to characterize and to compare the structural deformation of double-stranded oligomers bearing a single N-2-acetylaminofluorene (AAF) adduct covalently bound to each of the three guanine residues located within the frameshift mutation hot spot sequence -G1G2CG3CC-(NarI site). Two classes of chemical probes have been used, probes that sense the geometry of the helix, giving rise to cuts at every nucleotide (for example, 1,10-phenanthroline-copper), and probes that react with specific bases depending on their conformation (e.g., diethyl pyrocarbonate). For all probes that were tested, a distinct pattern of reactivity was observed according to the position of the adduct within the DNA sequence, revealing an important polymorphism in the adduct-induced DNA structure. With 1,10-phenanthroline-copper at least three base pairs 3' of the AAF-modified guanine were reactive on each strand, showing that the deformation of the DNA helix extends over a region of 4-6 bases pairs centered around the adduct and sensed by the probe in both strands. With the base-specific probes, reactivities were limited to the base complementary to the modified guanine and to adjacent bases. Within this sequence context, the three possible AAF adducts have previously been shown to exhibit strong differences in biological responses such as excision repair [Seeberg, E., & Fuchs, R. P. P. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 191-194] and mutagenesis [Burnouf, D., Koehl, P., & Fuchs, R. P. P. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 4147-4151].(ABSTRACT TRUNCATED AT 250 WORDS)
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26
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van Houte LP, Westra JG, Retèl J, van Grondelle R. A circular dichroism study on the conformation of d(CGT) modified with N-acetyl-2-aminofluorene or 2-aminofluorene. J Biomol Struct Dyn 1991; 9:45-59. [PMID: 1781947 DOI: 10.1080/07391102.1991.10507892] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The trinucleotide d(CGT) was modified by covalent binding of the carcinogen N-acetyl-2-aminofluorene (AAF) or 2-aminofluorene (AF) at the C8 position of the guanine base. The conformations of d(CGT)-AAF and -AF were studied by comparing the absorption and circular dichroism properties with those of dCMP + dGMP-AAF or -AF + dTMP in a molar ratio of 1:1:1 and AAF- and AF-containing dGMP. For both AAF- and AF-d(CGT) complexes the results show significant stacking interactions between the fluorene residue and the base(s) and are discussed in terms of the conformation of d(CGT)-AAF and -AF. In d(CGT)-AF we observe a clear interaction between AF and thymine, whereas the C-G stack is still intact. In the case of d(CGT)-AAF the C-G stack is weakened and the glycosidic rotation angle of dGuo-C8-AAF is most probably syn. The specific fluorene-base interactions persist at elevated temperatures. The carcinogen-base interactions are stronger in the AAF-carrying d(CGT) than in the case of the deacetylated complex. This is consistent with the higher mobility of the AF-adduct and its conformationally heterogeneous appearance in DNA.
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Affiliation(s)
- L P van Houte
- Free University, Department of Biophysics, Amsterdam, The Netherlands
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27
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Fritsch V, Westhof E. Minimization and molecular dynamics studies of guanosine and Z-DNA modified byN-2-acetylaminofluorene. J Comput Chem 1991. [DOI: 10.1002/jcc.540120203] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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28
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