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Moore MM, Pottenger LH, House‐Knight T. Critical review of styrene genotoxicity focused on the mutagenicity/clastogenicity literature and using current organization of economic cooperation and development guidance. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:624-663. [PMID: 30786062 PMCID: PMC6767453 DOI: 10.1002/em.22278] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 02/08/2019] [Accepted: 02/18/2019] [Indexed: 05/06/2023]
Abstract
Styrene is an important high production volume chemical used to manufacture polymeric products. In 2018, International Agency for Research on Cancer classified styrene as probably carcinogenic to humans; National Toxicology Program lists styrene as reasonably anticipated to be a human carcinogen. The genotoxicity literature for styrene and its primary metabolite, styrene 7,8-oxide (SO), begins in the 1970s. Organization of Economic Cooperation and Development (OECD) recently updated most genotoxicity test guidelines, making substantial new recommendations for assay conduct and data evaluation for the standard mutagenicity/clastogenicity assays. Thus, a critical review of the in vitro and in vivo rodent mutagenicity/clastogenicity studies for styrene and SO, based on the latest OECD recommendations, is timely. This critical review considered whether a study was optimally designed, conducted, and interpreted and provides a critical assessment of the evidence for the mutagenicity/clastogenicity of styrene/SO. Information on the ability of styrene/SO to induce other types of genotoxicity endpoints is summarized but not critically reviewed. We conclude that when styrene is metabolized to SO, it can form DNA adducts, and positive in vitro mutagenicity/clastogenicity results can be obtained. SO is mutagenic in bacteria and the in vitro mouse lymphoma gene mutation assay. No rodent in vivo mutation studies were identified. SO is clastogenic in cultured mammalian cells. Although the in vitro assays gave positive responses, styrene/SO is not clastogenic/aneugenic in vivo in rodents. In addition to providing updated information for styrene, this review demonstrates the application of the new OECD guidelines for chemicals with large genetic toxicology databases where published results may or may not be reliable. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Martha M. Moore
- Ramboll124 West Capitol Avenue, Suite 1605, Little RockArkansas
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5-Arylideneimidazolones with Amine at Position 3 as Potential Antibiotic Adjuvants against Multidrug Resistant Bacteria. Molecules 2019; 24:molecules24030438. [PMID: 30691112 PMCID: PMC6384991 DOI: 10.3390/molecules24030438] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 01/20/2019] [Accepted: 01/21/2019] [Indexed: 12/30/2022] Open
Abstract
Searching for new chemosensitizers of bacterial multidrug resistance (MDR), chemical modifications of (Z)-5-(4-chlorobenzylidene)-2-(4-methylpiperazin-1-yl)-3H-imidazol-4(5H)-one (6) were performed. New compounds (7⁻17), with fused aromatic rings at position 5, were designed and synthesized. Crystallographic X-ray analysis proved that the final compounds (7⁻17) were substituted with tertiary amine-propyl moiety at position 3 and primary amine group at 2 due to intramolecular Dimroth rearrangement. New compounds were evaluated on their antibiotic adjuvant properties in either Gram-positive or Gram-negative bacteria. Efflux pump inhibitor (EPI) properties towards the AcrAB-TolC pump in Enterobacter aerogenes (EA289) were investigated in the real-time efflux (RTE) assay. Docking and molecular dynamics were applied to estimate an interaction of compounds 6⁻17 with penicillin binding protein (PBP2a). In vitro ADME-Tox properties were evaluated for compound 9. Most of the tested compounds reduced significantly (4-32-fold) oxacillin MIC in highly resistant MRSA HEMSA 5 strain. The anthracene-morpholine derivative (16) was the most potent (32-fold reduction). The tested compounds displayed significant EPI properties during RTE assay (37⁻97%). The naphthyl-methylpiperazine derivative 9 showed the most potent "dual action" of both oxacillin adjuvant (MRSA) and EPI (E. aerogenes). Molecular modeling results suggested the allosteric mechanism of action of the imidazolones, which improved binding of oxacillin in the PBP2a active site in MRSA.
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Toxicology of DNA Adducts Formed Upon Human Exposure to Carcinogens. ADVANCES IN MOLECULAR TOXICOLOGY 2016. [DOI: 10.1016/b978-0-12-804700-2.00007-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Bailey LA, Nascarella MA, Kerper LE, Rhomberg LR. Hypothesis-based weight-of-evidence evaluation and risk assessment for naphthalene carcinogenesis. Crit Rev Toxicol 2015; 46:1-42. [PMID: 26202831 PMCID: PMC4732411 DOI: 10.3109/10408444.2015.1061477] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 06/09/2015] [Indexed: 11/13/2022]
Abstract
Inhalation of naphthalene causes olfactory epithelial nasal tumors in rats (but not in mice) and benign lung adenomas in mice (but not in rats). The limited available human data have not identified an association between naphthalene exposure and increased respiratory cancer risk. Assessing naphthalene's carcinogenicity in humans, therefore, depends entirely on experimental evidence from rodents. We evaluated the respiratory carcinogenicity of naphthalene in rodents, and its potential relevance to humans, using our Hypothesis-Based Weight-of-Evidence (HBWoE) approach. We systematically and comparatively reviewed data relevant to key elements in the hypothesized modes of action (MoA) to determine which is best supported by the available data, allowing all of the data from each realm of investigation to inform interpretation of one another. Our analysis supports a mechanism that involves initial metabolism of naphthalene to the epoxide, followed by GSH depletion, cytotoxicity, chronic inflammation, regenerative hyperplasia, and tumor formation, with possible weak genotoxicity from downstream metabolites occurring only at high cytotoxic doses, strongly supporting a non-mutagenic threshold MoA in the rat nose. We also conducted a dose-response analysis, based on the likely MoA, which suggests that the rat nasal MoA is not relevant in human respiratory tissues at typical environmental exposures. Our analysis illustrates how a thorough WoE evaluation can be used to support a MoA, even when a mechanism of action cannot be fully elucidated. A non-mutagenic threshold MoA for naphthalene-induced rat nasal tumors should be considered as a basis to determine human relevance and to guide regulatory and risk-management decisions.
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Kowal EA, Wickramaratne S, Kotapati S, Turo M, Tretyakova N, Stone MP. Major groove orientation of the (2S)-N(6)-(2-hydroxy-3-buten-1-yl)-2'-deoxyadenosine DNA adduct induced by 1,2-epoxy-3-butene. Chem Res Toxicol 2014; 27:1675-86. [PMID: 25238403 PMCID: PMC4203389 DOI: 10.1021/tx500159w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Indexed: 02/08/2023]
Abstract
1,3-Butadiene (BD) is an environmental and occupational toxicant classified as a human carcinogen. It is oxidized by cytochrome P450 monooxygenases to 1,2-epoxy-3-butene (EB), which alkylates DNA. BD exposures lead to large numbers of mutations at A:T base pairs even though alkylation of guanines is more prevalent, suggesting that one or more adenine adducts of BD play a role in BD-mediated genotoxicity. However, the etiology of BD-mediated genotoxicity at adenine remains poorly understood. EB alkylates the N(6) exocyclic nitrogen of adenine to form N(6)-(hydroxy-3-buten-1-yl)-2'-dA ((2S)-N(6)-HB-dA) adducts ( Tretyakova , N. , Lin , Y. , Sangaiah , R. , Upton , P. B. , and Swenberg , J. A. ( 1997 ) Carcinogenesis 18 , 137 - 147 ). The structure of the (2S)-N(6)-HB-dA adduct has been determined in the 5'-d(C(1)G(2)G(3)A(4)C(5)Y(6)A(7)G(8)A(9)A(10)G(11))-3':5'-d(C(12)T(13)T(14)C(15)T(16)T(17)G(18)T(19) C(20)C(21)G(22))-3' duplex [Y = (2S)-N(6)-HB-dA] containing codon 61 (underlined) of the human N-ras protooncogene, from NMR spectroscopy. The (2S)-N(6)-HB-dA adduct was positioned in the major groove, such that the butadiene moiety was oriented in the 3' direction. At the Cα carbon, the methylene protons of the modified nucleobase Y(6) faced the 5' direction, which placed the Cβ carbon in the 3' direction. The Cβ hydroxyl group faced toward the solvent, as did carbons Cγ and Cδ. The Cβ hydroxyl group did not form hydrogen bonds with either T(16) O(4) or T(17) O(4). The (2S)-N(6)-HB-dA nucleoside maintained the anti conformation about the glycosyl bond, and the modified base retained Watson-Crick base pairing with the complementary base (T(17)). The adduct perturbed stacking interactions at base pairs C(5):G(18), Y(6):T(17), and A(7):T(16) such that the Y(6) base did not stack with its 5' neighbor C(5), but it did with its 3' neighbor A(7). The complementary thymine T(17) stacked well with both 5' and 3' neighbors T(16) and G(18). The presence of the (2S)-N(6)-HB-dA resulted in a 5 °C reduction in the Tm of the duplex, which is attributed to less favorable stacking interactions and adduct accommodation in the major groove.
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Affiliation(s)
- Ewa A. Kowal
- Department
of Chemistry, Center in Molecular Toxicology, Vanderbilt Ingram Cancer
Center, and Center for Structural Biology, Vanderbilt University, 2201 West End Avenue, Nashville, Tennessee 37235, United States
| | - Susith Wickramaratne
- Department
of Medicinal Chemistry, Masonic Cancer Center, and Department of Chemistry, University of Minnesota, Minneapolis Minnesota 55455, United States
| | - Srikanth Kotapati
- Department
of Medicinal Chemistry, Masonic Cancer Center, and Department of Chemistry, University of Minnesota, Minneapolis Minnesota 55455, United States
| | - Michael Turo
- Department
of Chemistry, Center in Molecular Toxicology, Vanderbilt Ingram Cancer
Center, and Center for Structural Biology, Vanderbilt University, 2201 West End Avenue, Nashville, Tennessee 37235, United States
| | - Natalia Tretyakova
- Department
of Medicinal Chemistry, Masonic Cancer Center, and Department of Chemistry, University of Minnesota, Minneapolis Minnesota 55455, United States
| | - Michael P. Stone
- Department
of Chemistry, Center in Molecular Toxicology, Vanderbilt Ingram Cancer
Center, and Center for Structural Biology, Vanderbilt University, 2201 West End Avenue, Nashville, Tennessee 37235, United States
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Shen LC, Chiang SY, Ho IT, Wu KY, Chung WS. Synthesis and Characterization of Adducts Formed in the Reactions of Safrole 2′,3′-Oxide with 2′-Deoxyadenosine, Adenine, and Calf Thymus DNA. European J Org Chem 2011. [DOI: 10.1002/ejoc.201101384] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Rhomberg LR, Bailey LA, Goodman JE. Hypothesis-based weight of evidence: A tool for evaluating and communicating uncertainties and inconsistencies in the large body of evidence in proposing a carcinogenic mode of action—naphthalene as an example. Crit Rev Toxicol 2010; 40:671-96. [PMID: 20722583 DOI: 10.3109/10408444.2010.499504] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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El Ashry ESH, Nadeem S, Shah MR, Kilany YE. Recent Advances in the Dimroth Rearrangement. ADVANCES IN HETEROCYCLIC CHEMISTRY 2010. [DOI: 10.1016/s0065-2725(10)01005-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Ding H, Majumdar A, Tolman JR, Greenberg MM. Multinuclear NMR and kinetic analysis of DNA interstrand cross-link formation. J Am Chem Soc 2008; 130:17981-7. [PMID: 19053196 PMCID: PMC2653107 DOI: 10.1021/ja807845n] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Recently, a phenylselenyl-modified thymidine (2) was shown to produce DNA interstrand cross-links (ICLs) via two mechanisms. Photolysis of 2 generates 5-(2'-deoxyuridinyl)methyl radical (1), the reactive intermediate that results from formal hydrogen atom abstraction from the thymine methyl group. This reactive intermediate reacts with the opposing dA and is the first example of a DNA radical that produces ICLs. Kinetic competition studies support the proposal that the rate-limiting step in ICL formation from 1 involves rotation about the glycosidic bond and that the rate constant for this process is influenced by the flanking sequence. Cross-links also form with the opposing dA when 2 is treated with mild oxidants that result in the formation of an intermediate methide-like species (4). Kinetic experiments reveal that 4 reacts with azide, a model nucleophile, via an S(N)2' pathway. Previous experiments suggested that the same product is produced via 1 or 4 but that the initially formed cross-link rearranges during the enzyme digestion and isolation procedures. In situ product analysis by NMR using synthetic, doubly labeled duplex DNA containing (13)C-2 and (15)N(1)-dA provides definitive evidence that the kinetic ICL products formed via the radical and oxidative pathways are the same and correspond to that arising from formal alkylation of N(1)-dA. Furthermore, analysis of the thermodynamic product formed upon rearrangement indicates that the primary product isomerizes via an associative mechanism in DNA.
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Affiliation(s)
- Hui Ding
- Department of Chemistry and Biomolecular NMR Center, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
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Antunes AMM, Duarte MP, Santos PP, Gamboa da Costa G, Heinze TM, Beland FA, Marques MM. Synthesis and Characterization of DNA Adducts from the HIV Reverse Transcriptase Inhibitor Nevirapine. Chem Res Toxicol 2008; 21:1443-56. [DOI: 10.1021/tx8000972] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Alexandra M. M. Antunes
- REQUIMTE/CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Centro de Química Estrutural, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal, and Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Mariana P. Duarte
- REQUIMTE/CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Centro de Química Estrutural, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal, and Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Pedro P. Santos
- REQUIMTE/CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Centro de Química Estrutural, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal, and Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Gonçalo Gamboa da Costa
- REQUIMTE/CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Centro de Química Estrutural, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal, and Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Thomas M. Heinze
- REQUIMTE/CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Centro de Química Estrutural, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal, and Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Frederick A. Beland
- REQUIMTE/CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Centro de Química Estrutural, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal, and Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - M. Matilde Marques
- REQUIMTE/CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Centro de Química Estrutural, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal, and Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079
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Xu W, Merritt WK, Nechev LV, Harris TM, Harris CM, Lloyd RS, Stone MP. Structure of the 1,4-Bis(2'-deoxyadenosin-N(6)-yl)-2S,3S-butanediol intrastrand DNA cross-link arising from butadiene diepoxide in the human N-ras codon 61 sequence. Chem Res Toxicol 2007; 20:187-98. [PMID: 17256975 PMCID: PMC2597494 DOI: 10.1021/tx060210a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The 1,4-bis(2'-deoxyadenosin-N(6)-yl)-2S,3S-butanediol intrastrand DNA cross-link arises from the bis-alkylation of tandem N(6)-dA sites in DNA by R,R-butadiene diepoxide (BDO(2)). The oligodeoxynucleotide 5'-d(C(1)G(2)G(3)A(4)C(5)X(6)Y(7)G(8)A(9)A(10)G(11))-3'.5'-d(C(12)T(13)T(14)C(15)T(16)T(17)G(18)T(19)C(20)C(21)G(22))-3' contains the BDO(2) cross-link between the second and third adenines of the codon 61 sequence (underlined) of the human N-ras protooncogene and is named the (S,S)-BD-(61-2,3) cross-link (X,Y = cross-linked adenines). NMR analysis reveals that the cross-link is oriented in the major groove of duplex DNA. Watson-Crick base pairing is perturbed at base pair X(6).T(17), whereas base pairing is intact at base pair Y(7).T(16). The cross-link appears to exist in two conformations, in rapid exchange on the NMR time scale. In the first conformation, the beta-OH is predicted to form a hydrogen bond with T(16) O(4), whereas in the second, the beta-OH is predicted to form a hydrogen bond with T(17) O(4). In contrast to the (R,R)-BD-(61-2,3) cross-link in the same sequence (Merritt, W. K., Nechev, L. V., Scholdberg, T. A., Dean, S. M., Kiehna, S. E., Chang, J. C., Harris, T. M., Harris, C. M., Lloyd, R. S., and Stone, M. P. (2005) Biochemistry 44, 10081-10092), the anti-conformation of the two hydroxyl groups at C(beta) and C(gamma) with respect to the C(beta)-C(gamma) bond results in a decreased twist between base pairs X(6).T(17) and Y(7).T(16), and an approximate 10 degrees bending of the duplex. These conformational differences may account for the differential mutagenicity of the (S,S)- and (R,R)-BD-(61-2,3) cross-links and suggest that stereochemistry plays a role in modulating biological responses to these cross-links (Kanuri, M., Nechev, L. V., Tamura, P. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2002) Chem. Res. Toxicol. 15, 1572-1580).
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Affiliation(s)
- Wen Xu
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | | | | | - Thomas M. Harris
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | - Constance M. Harris
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | | | - Michael P. Stone
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
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Kanuri M, Nechev LV, Kiehna SE, Tamura PJ, Harris CM, Harris TM, Lloyd RS. Evidence for Escherichia coli polymerase II mutagenic bypass of intrastrand DNA crosslinks. DNA Repair (Amst) 2005; 4:1374-80. [PMID: 16257273 DOI: 10.1016/j.dnarep.2005.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The mutagenic potentials of DNAs containing site- and stereospecific intrastrand DNA crosslinks were evaluated in Escherichia coli cells that contained a full complement of DNA polymerases or were deficient in either polymerases II, IV, or V. Crosslinks were made between adjacent N(6)-N(6) adenines and consisted of R,R- and S,S-butadiene crosslinks and unfunctionalized 2-, 3-, and 4-carbon tethers. Although replication of single-stranded DNAs containing the unfunctionalized 3- and 4-carbon tethers were non-mutagenic in all strains tested, replication past all the other intrastrand crosslinks was mutagenic in all E. coli strains, except the one deficient in polymerase II in which no mutations were ever detected. However, when mutagenesis was analyzed in cells induced for SOS, mutations were not detected, suggesting a possible change in the overall fidelity of polymerase II under SOS conditions. These data suggest that DNA polymerase II is responsible for the in vivo mutagenic bypass of these lesions in wild-type E. coli.
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Affiliation(s)
- Manorama Kanuri
- Sealy Center for Molecular Science, University of Texas Medical Branch, Galveston, 77550, USA
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Merritt WK, Nechev LV, Scholdberg TA, Dean SM, Kiehna SE, Chang JC, Harris TM, Harris CM, Lloyd RS, Stone MP. Structure of the 1,4-bis(2'-deoxyadenosin-N6-yl)-2R,3R-butanediol cross-link arising from alkylation of the human N-ras codon 61 by butadiene diepoxide. Biochemistry 2005; 44:10081-92. [PMID: 16042385 PMCID: PMC2585418 DOI: 10.1021/bi047263g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The solution structure of the 1,4-bis(2'-deoxyadenosin-N(6)-yl)-2R,3R-butanediol cross-link arising from N(6)-dA alkylation of nearest-neighbor adenines by butadiene diepoxide (BDO(2)) was determined in the oligodeoxynucleotide 5'-d(CGGACXYGAAG)-3'.5'-d(CTTCTTGTCCG)-3'. This oligodeoxynucleotide contained codon 61 (underlined) of the human N-ras protooncogene. The cross-link was accommodated in the major groove of duplex DNA. At the 5'-side of the cross-link there was a break in Watson-Crick base pairing at base pair X(6).T(17), whereas at the 3'-side of the cross-link at base pair Y(7).T(16), base pairing was intact. Molecular dynamics calculations carried out using a simulated annealing protocol, and restrained by a combination of 338 interproton distance restraints obtained from (1)H NOESY data and 151 torsion angle restraints obtained from (1)H and (31)P COSY data, yielded ensembles of structures with good convergence. Helicoidal analysis indicated an increase in base pair opening at base pair X(6).T(17), accompanied by a shift in the phosphodiester backbone torsion angle beta P5'-O5'-C5'-C4' at nucleotide X(6). The rMD calculations predicted that the DNA helix was not significantly bent by the presence of the four-carbon cross-link. This was corroborated by gel mobility assays of multimers containing nonhydroxylated four-carbon N(6),N(6)-dA cross-links, which did not predict DNA bending. The rMD calculations suggested the presence of hydrogen bonding between the hydroxyl group located on the beta-carbon of the four-carbon cross-link and T(17) O(4), which perhaps stabilized the base pair opening at X(6).T(17) and protected the T(17) imino proton from solvent exchange. The opening of base pair X(6).T(17) altered base stacking patterns at the cross-link site and induced slight unwinding of the DNA duplex. The structural data are interpreted in terms of biochemical data suggesting that this cross-link is bypassed by a variety of DNA polymerases, yet is significantly mutagenic [Kanuri, M., Nechev, L. V., Tamura, P. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2002) Chem. Res. Toxicol. 15, 1572-1580].
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Affiliation(s)
- W. Keither Merritt
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | | | | | - Stephen M. Dean
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | - Sarah E. Kiehna
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | - Johanna C. Chang
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | - Thomas M. Harris
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | - Constance M. Harris
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
| | | | - Michael P. Stone
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235
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Kanuri M, Finneman J, Harris CM, Harris TM, Lloyd RS. Efficient nonmutagenic replication bypass of DNAs containing beta-adducts of styrene oxide at adenine N(6). ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2001; 38:357-360. [PMID: 11774368 DOI: 10.1002/em.10030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- M Kanuri
- Sealy Center for Molecular Science, The University of Texas Medical Branch, Galveston, Texas 77555-1071, USA
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