1
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Mantle P. Optimised Fermentation Production of Radiolabelled Ochratoxin A by Aspergillus ochraceus with Maximum 14C in the Pentaketide Moiety for Exploring Its Rat Renal Toxicology. Toxins (Basel) 2023; 16:8. [PMID: 38251225 PMCID: PMC10820727 DOI: 10.3390/toxins16010008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 11/29/2023] [Accepted: 12/04/2023] [Indexed: 01/23/2024] Open
Abstract
In the context of the mysterious Balkan endemic nephropathy of the 1900s, and the discovery in the 1960s of the potent mycotoxin ochratoxin A, experimental research projects sought to explore any inter-relationship. Experimental lifetime administration of the toxin to male rats had revealed renal DNA adducts with the toxin, correlated with renal tumours, confirmation of which required molecular evidence. Consequently, production of 14C-ochratoxin A of a high specific radioactivity was required, practical biosynthetic detail of which had not previously been published. A fermentation study of Aspergillus ochraceous was carried out during 2002 for a European project, to select for the production of high-quality 14C-ochratoxin A, necessarily exploring for the maximum diversion of 14C-sodium acetate into the pentaketide portion of mycotoxin. Experimentation necessarily had to optimise the competitive context of fungal growth dynamics and addition of the biosynthetic precursor in the early days of shaken-flask fermentation before adding the radiolabelled precursor. From optimal fermentation, 50 mg of the 14C ochratoxin A was supplied within a European project for DNA adduct experimentation, but that proved negative as subsequently published. Experimental description of the radiolabelled ochratoxin A production was later made in a doctoral thesis, but is first publicised here. Further review of the literature reveals an explanation for the published failure to confirm rat DNA/ochratoxin A adduct formation, for which further experimentation is now recommended.
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Affiliation(s)
- Peter Mantle
- Centre for Environmental Policy, Imperial College London, London SW7 2AZ, UK
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2
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Negi I, Singh B, Singh Mahmi A, Sharma P. Structural Properties of Hachimoji Nucleic Acids and Their Building Blocks: Comparison of Genetic Systems with Four, Six and Eight Alphabets. Chemphyschem 2023; 24:e202200714. [PMID: 36315394 DOI: 10.1002/cphc.202200714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/29/2022] [Indexed: 11/07/2022]
Abstract
Expansion of the genetic alphabet is an ambitious goal. A recent breakthrough has led to the eight-base (hachimoji) genetics having canonical and unnatural bases. However, very little is known on the molecular-level features that facilitate the candidature of unnatural bases as genetic alphabets. Here we amalgamated DFT calculations and MD simulations to analyse the properties of the constituents of hachimoji DNA and RNA. DFT reveals the dominant syn conformation for isolated unnatural deoxyribonucleosides and at the 5'-end of oligonucleotides, although an anti/syn mixture is predicted at the nonterminal and 3'-terminal positions. However, isolated ribonucleotides prefer an anti/syn mixture, but mostly prefer anti conformation at the nonterminal positions. Further, the canonical base pairing combinations reveals significant strength, which may facilitate replication of hachimoji DNA. We also identify noncanonical base pairs that can better tolerate the substitution of unnatural pairs in RNA. Stacking strengths of 51 dimers reveals higher average stacking stabilization of dimers of hachimoji bases than canonical bases, which provides clues for choosing energetically stable sequences. A total of 14.4 μs MD simulations reveal the influence of solvent on the properties of hachimoji oligonucleotides and point to the likely fidelity of replication of hachimoji DNA. Our results pinpoint the features that explain the experimentally observed stability of hachimoji DNA.
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Affiliation(s)
- Indu Negi
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - Bimaldeep Singh
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - Amanpreet Singh Mahmi
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India.,Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Ave., Windsor, ON, N9B 3P4, Canada
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3
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Wilson KA, Jeong YER, Wetmore SD. Multiscale computational investigations of the translesion synthesis bypass of tobacco-derived DNA adducts: critical insights that complement experimental biochemical studies. Phys Chem Chem Phys 2022; 24:10667-10683. [PMID: 35502640 DOI: 10.1039/d2cp00481j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Among the numerous agents that damage DNA, tobacco products remain one of the most lethal and result in the most diverse set of DNA lesions. This perspective aims to provide an overview of computational work conducted to complement experimental biochemical studies on the mutagenicity of adducts derived from the most potent tobacco carcinogen, namely 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (nicotine-derived nitrosaminoketone or NNK). Lesions ranging from the smallest methylated thymine derivatives to the larger, flexible pyridyloxobutyl (POB) guanine adducts are considered. Insights are obtained from density functional theory (DFT) calculations and molecular dynamics (MD) simulations into the damaged nucleobase and nucleoside structures, the accommodation of the lesions in the active site of key human polymerases, the intrinsic base pairing potentials of the adducts, and dNTP incorporation opposite the lesions. Overall, the computational data provide atomic level information that can rationalize the differential mutagenic properties of tobacco-derived lesions and uncover important insights into the impact of adduct size, nucleobase, position, and chemical composition of the bulky moiety.
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Affiliation(s)
- Katie A Wilson
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute (ARRTI) and Southern Alberta Genome Sciences Center (SAGSC), University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
| | - Ye Eun Rebecca Jeong
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute (ARRTI) and Southern Alberta Genome Sciences Center (SAGSC), University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute (ARRTI) and Southern Alberta Genome Sciences Center (SAGSC), University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
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4
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Dey DK, Kang JI, Bajpai VK, Kim K, Lee H, Sonwal S, Simal-Gandara J, Xiao J, Ali S, Huh YS, Han YK, Shukla S. Mycotoxins in food and feed: toxicity, preventive challenges, and advanced detection techniques for associated diseases. Crit Rev Food Sci Nutr 2022; 63:8489-8510. [PMID: 35445609 DOI: 10.1080/10408398.2022.2059650] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Mycotoxins are produced primarily as secondary fungal metabolites. Mycotoxins are toxic in nature and naturally produced by various species of fungi, which usually contaminate food and feed ingredients. The growth of these harmful fungi depends on several environmental factors, such as pH, humidity, and temperature; therefore, the mycotoxin distribution also varies among global geographical areas. Various rules and regulations regarding mycotoxins are imposed by the government bodies of each country, which are responsible for addressing global food and health security concerns. Despite this legislation, the incidence of mycotoxin contamination is continuously increasing. In this review, we discuss the geographical regulatory guidelines and recommendations that are implemented around the world to control mycotoxin contamination of food and feed products. Researchers and inventors from various parts of the world have reported several innovations for controlling mycotoxin-associated health consequences. Unfortunately, most of these techniques are restricted to laboratory scales and cannot reach users. Consequently, to date, no single device has been commercialized that can detect all mycotoxins that are naturally available in the environment. Therefore, in this study, we describe severe health hazards that are associated with mycotoxin exposure, their molecular signaling pathways and processes of toxicity, and their genotoxic and cytotoxic effects toward humans and animals. We also discuss recent developments in the construction of a sensitive and specific device that effectively implements mycotoxin identification and detection methods. In addition, our study comprehensively examines the recent advancements in the field for mitigating the health consequences and links them with the molecular and signaling pathways that are activated upon mycotoxin exposure.
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Affiliation(s)
- Debasish Kumar Dey
- Department of Biotechnology, Daegu University, Gyeongsan, Republic of Korea
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Ji In Kang
- Anticancer Agents Research Center, Korea Research Institute of Bioscience and Biotechnology, Ochang, Cheongwon, Republic of Korea
| | - Vivek K Bajpai
- Department of Energy and Materials Engineering, Dongguk University, Seoul, Republic of Korea
| | - Kwanwoo Kim
- Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, Incheon, Republic of Korea
| | - Hoomin Lee
- Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, Incheon, Republic of Korea
| | - Sonam Sonwal
- Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, Incheon, Republic of Korea
| | - Jesus Simal-Gandara
- Department of Analytical Chemistry and Food Science, Faculty of Food Science and Technology, University of Vigo - Ourense Campus, Ourense, Spain
| | - Jianbo Xiao
- Department of Analytical Chemistry and Food Science, Faculty of Food Science and Technology, University of Vigo - Ourense Campus, Ourense, Spain
| | - Sajad Ali
- Department of Biotechnology, Yeungnam University, Gyeongsan, Republic of Korea
| | - Yun Suk Huh
- Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, Incheon, Republic of Korea
| | - Yong-Kyu Han
- Department of Energy and Materials Engineering, Dongguk University, Seoul, Republic of Korea
| | - Shruti Shukla
- TERI-Deakin Nanobiotechnology Centre, The Energy and Resources Institute, Gurugram, Haryana, India
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5
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Balasubramaniyam T, Oh KI, Jin HS, Ahn HB, Kim BS, Lee JH. Non-Canonical Helical Structure of Nucleic Acids Containing Base-Modified Nucleotides. Int J Mol Sci 2021; 22:9552. [PMID: 34502459 PMCID: PMC8430589 DOI: 10.3390/ijms22179552] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/27/2021] [Accepted: 08/29/2021] [Indexed: 12/12/2022] Open
Abstract
Chemically modified nucleobases are thought to be important for therapeutic purposes as well as diagnosing genetic diseases and have been widely involved in research fields such as molecular biology and biochemical studies. Many artificially modified nucleobases, such as methyl, halogen, and aryl modifications of purines at the C8 position and pyrimidines at the C5 position, are widely studied for their biological functions. DNA containing these modified nucleobases can form non-canonical helical structures such as Z-DNA, G-quadruplex, i-motif, and triplex. This review summarizes the synthesis of chemically modified nucleotides: (i) methylation, bromination, and arylation of purine at the C8 position and (ii) methylation, bromination, and arylation of pyrimidine at the C5 position. Additionally, we introduce the non-canonical structures of nucleic acids containing these modifications.
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Affiliation(s)
- Thananjeyan Balasubramaniyam
- Department of Chemistry, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea; (T.B.); (K.-I.O.); (H.-S.J.); (H.-B.A.)
- The Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea
| | - Kwnag-Im Oh
- Department of Chemistry, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea; (T.B.); (K.-I.O.); (H.-S.J.); (H.-B.A.)
- The Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea
| | - Ho-Seong Jin
- Department of Chemistry, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea; (T.B.); (K.-I.O.); (H.-S.J.); (H.-B.A.)
| | - Hye-Bin Ahn
- Department of Chemistry, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea; (T.B.); (K.-I.O.); (H.-S.J.); (H.-B.A.)
| | - Byeong-Seon Kim
- The Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea
- Department of Chemistry Education, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea
| | - Joon-Hwa Lee
- Department of Chemistry, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea; (T.B.); (K.-I.O.); (H.-S.J.); (H.-B.A.)
- The Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Gyeongnam, Korea
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6
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Kathuria P, Singh P, Sharma P, Manderville RA, Wetmore SD. Molecular Dynamics Study of One-Base Deletion Duplexes Containing the Major DNA Adduct Formed by Ochratoxin A: Effects of Sequence Context and Adduct Ionization State on Lesion Site Structure and Mutagenicity. J Phys Chem B 2019; 123:6980-6989. [PMID: 31311268 DOI: 10.1021/acs.jpcb.9b06489] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Ochratoxin A (OTA) is a ubiquitous food toxin associated with chronic nephropathy in humans and renal carcinogenicity in rodents. The mutational spectra of cells exposed to OTA reveal that one-base deletions comprise the largest percentage (73%) of the total mutations that occur upon OTA exposure. To contribute toward understanding the prevalence of OTA-induced one-base deletion mutations, the present work uses molecular dynamics (MD) simulations to analyze the conformational preferences of one-base deletion duplexes containing OT-G, the major OTA adduct (addition product) at the C8-site of guanine. Specifically, the influence of OT-G in four possible ionization states and three sequence contexts (G1, G2 and G3 in the NarI (5'-G1G2CG3CC-3'), a prokaryotic mutational hotspot sequence) on the structure of the adducted DNA is investigated. Our data reveal that the damaged helices are stable in two (B-type (B) and stacked (S)) conformations that are structurally similar to those adopted by common N-linked C8-guanine lesions. However, the adduct ionization state and sequence context affect the degree of helical distortion and the B/S conformational heterogeneity, which will impact the lesion repair and replication outcomes. This finding correlates with the experimentally reported tissue-specific mutagenicity of OTA exposure. Furthermore, regardless of the adduct conformation, ionization state, or sequence context, more stable lesion-site interactions and lack of disruption of the flanking base pairs in the one-base deletion duplexes compared to the corresponding two-base deletion helices rationalize the greater abundance of OTA induced one-base deletions. Overall, our work provides valuable structural insights that help explain the experimentally observed mutagenicity associated with OTA.
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Affiliation(s)
- Preetleen Kathuria
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry , Panjab University , Chandigarh 160014 , India
| | - Prebhleen Singh
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry , Panjab University , Chandigarh 160014 , India
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry , Panjab University , Chandigarh 160014 , India
| | - Richard A Manderville
- Departments of Chemistry and Toxicology , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry , University of Lethbridge , Lethbridge , Alberta T1K 3M4 , Canada
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7
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Kathuria P, Sharma P, Manderville RA, Wetmore SD. Molecular Dynamics Simulations of Mismatched DNA Duplexes Associated with the Major C8-Linked 2′-Deoxyguanosine Adduct of the Food Mutagen Ochratoxin A: Influence of Opposing Base, Adduct Ionization State, and Sequence on the Structure of Damaged DNA. Chem Res Toxicol 2018; 31:712-720. [DOI: 10.1021/acs.chemrestox.8b00064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Preetleen Kathuria
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Richard A. Manderville
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Stacey D. Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
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8
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Vongsutilers V, Gannett PM. C8-Guanine modifications: effect on Z-DNA formation and its role in cancer. Org Biomol Chem 2018. [DOI: 10.1039/c8ob00030a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Participation of Z DNA in normal and disease related biological processes.
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Affiliation(s)
- V. Vongsutilers
- Department of Food and Pharmaceutical Chemistry
- Faculty of Pharmaceutical Sciences
- Chulalongkorn University
- Thailand
| | - P. M. Gannett
- College of Pharmacy
- Nova Southeastern University
- Ft. Lauderdale
- USA
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9
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Manderville RA, Wetmore SD. Mutagenicity of Ochratoxin A: Role for a Carbon-Linked C8-Deoxyguanosine Adduct? JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:7097-7105. [PMID: 28830149 DOI: 10.1021/acs.jafc.6b03897] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Ochratoxin A (OTA) is a fungal toxin that is considered to be a potent kidney carcinogen in rodent models. The toxin produces double strand breaks and has a propensity for deletions, single-base substitutions, and insertions. The toxin reacts covalently with DNA to afford a C8-2'-deoxyguanosine carbon-linked adduct (OT-dG) as the major lesion in animal tissues. Incorporation of model C-linked C8-aryl-dG adducts into the G3 site of the NarI sequence demonstrates a tendency to induce base substitutions and deletion mutations in primer extension assays using model polymerases. The degree of misincorporation induced by the C-linked C8-dG adducts correlates with an ability to adopt the promutagenic syn conformation within the NarI duplex as predicted by molecular dynamics (MD) simulations. MD simulations of the OT-dG adduct within the NarI duplex predict an even greater degree of conformational flexibility, suggesting enhanced in vitro mutagenicity compared to the simpler model C-linked C8-dG adducts. Together these findings support the role of OT-dG in promoting OTA-mediated mutagenicity and carcinogenicity in animal studies.
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Affiliation(s)
- Richard A Manderville
- Departments of Chemistry and Toxicology, University of Guelph , Guelph, Ontario, Canada N1G 2W1
| | - Stacey D Wetmore
- Department of Chemistry & Biochemistry, University of Lethbridge , Lethbridge, Alberta, Canada T1K 3M4
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10
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Kathuria P, Sharma P, Manderville RA, Wetmore SD. Molecular Modeling of the Major DNA Adduct Formed from Food Mutagen Ochratoxin A in NarI Two-Base Deletion Duplexes: Impact of Sequence Context and Adduct Ionization on Conformational Preference and Mutagenicity. Chem Res Toxicol 2017; 30:1582-1591. [PMID: 28719194 DOI: 10.1021/acs.chemrestox.7b00103] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Exposure to ochratoxin A (OTA), a possible human carcinogen, leads to many different DNA mutations. As a first step toward understanding the structural basis of OTA-induced mutagenicity, the present work uses a robust computational approach and a slipped mutagenic intermediate model previously studied for C8-dG aromatic amine adducts to analyze the conformational features of postreplication two-base deletion DNA duplexes containing OT-dG, the major OTA lesion at the C8 position of guanine. Specifically, a total of 960 ns of molecular dynamics simulations (excluding trial simulations) were carried out on four OT-dG ionization states in three sequence contexts within oligomers containing the NarI recognition sequence, a known hotspot for deletion mutations induced by related adducts formed from known carcinogens. Our results indicate that the structural properties and relative stability of the competing "major groove" and "stacked" conformations of OTA adducted two-base deletion duplexes depend on both the OTA ionization state and the sequence context, mainly due to conformation-dependent deviations in discrete local (hydrogen-bonding and stacking) interactions at the lesion site, as well as DNA bending. When the structural characteristics of the OT-dG adducted two-base deletion duplexes are compared to those associated with previously studied C8-dG adducts, a greater understanding of the effects of the nucleobase-carcinogen linkage, and size of the carcinogenic moiety on the conformational preferences of damaged DNA is obtained. Most importantly, our work predicts key structural features for OT-dG-adducted deletion DNA duplexes, which in turn allow us to develop hypotheses regarding OT-dG replication outcomes. Thus, our computational results are valuable for the design and interpretation of future biochemical studies on the potentially carcinogenic OT-dG lesion.
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Affiliation(s)
- Preetleen Kathuria
- Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University , Chandigarh 160014, India
| | - Purshotam Sharma
- Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University , Chandigarh 160014, India
| | - Richard A Manderville
- Departments of Chemistry and Toxicology, University of Guelph , Guelph, Ontario N1G 2W1, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge , Lethbridge, Alberta T1K 3M4, Canada
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11
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Manderville RA, Wetmore SD. Understanding the Mutagenicity of O-Linked and C-Linked Guanine DNA Adducts: A Combined Experimental and Computational Approach. Chem Res Toxicol 2016; 30:177-188. [DOI: 10.1021/acs.chemrestox.6b00323] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Richard A. Manderville
- Departments
of Chemistry and Toxicology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Stacey D. Wetmore
- Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4
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12
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Kathuria P, Sharma P, Wetmore SD. Effect of base sequence context on the conformational heterogeneity of aristolactam-I adducted DNA: structural and energetic insights into sequence-dependent repair and mutagenicity. Toxicol Res (Camb) 2016; 5:197-209. [PMID: 30090337 PMCID: PMC6061885 DOI: 10.1039/c5tx00302d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 10/19/2015] [Indexed: 11/21/2022] Open
Abstract
Aristolochic acids (AAs) are nephrotoxic and potentially carcinogenic plant mutagens that form bulky DNA adducts at the exocyclic amino groups of the purines. The present work utilizes classical molecular dynamics simulations and free energy calculations to investigate the role of lesion site sequence context in dictating the conformational outcomes of DNA containing ALI-N6-dA, the most persistent and mutagenic adduct arising from the AAs. Our calculations reveal that the anti base-displaced intercalated conformer is the lowest energy conformer of damaged DNA in all sequence contexts considered (CXC, CXG, GXC and GXG). However, the experimentally-observed greater mutagenicity of the adduct in the CXG sequence context does not correlate with the relative thermodynamic stability of the adduct in different sequences. Instead, AL-N6-dA adducted DNA is least distorted in the CXG sequence context, which points toward a possible differential repair propensity of the lesion in different sequences. Nevertheless, the structural deviations between adducted DNA with different lesion site sequences are small, and therefore other factors (such as interactions between the adducted DNA and lesion-bypass polymerases during replication) are likely more important for dictating the observed sequence-dependent mutagenicity of ALI-N6-dA.
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Affiliation(s)
- Preetleen Kathuria
- Department of Chemistry and Biochemistry , University of Lethbridge , 4401 University Drive West , Lethbridge , Alberta , Canada T1K 3M4 . ; ; Tel: +1 403-329-2323
| | - Purshotam Sharma
- Department of Chemistry and Biochemistry , University of Lethbridge , 4401 University Drive West , Lethbridge , Alberta , Canada T1K 3M4 . ; ; Tel: +1 403-329-2323
- Centre for Computational Sciences , Central University of Punjab , Bathinda , Punjab , India 151001
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry , University of Lethbridge , 4401 University Drive West , Lethbridge , Alberta , Canada T1K 3M4 . ; ; Tel: +1 403-329-2323
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13
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Jena NR, Bansal M, Mishra PC. Conformational stabilities of iminoallantoin and its base pairs in DNA: implications for mutagenicity. Phys Chem Chem Phys 2016; 18:12774-83. [DOI: 10.1039/c6cp02212j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Under acidic conditions, insertion of G opposite Ia may lead to G to C mutations in DNA.
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Affiliation(s)
- N. R. Jena
- Discipline of Natural Sciences
- Indian Institute of Information Technology
- Design and Manufacturing
- Jabalpur-482005
- India
| | - Manju Bansal
- Molecular Biophysics Unit
- Indian Institute of Science
- Bangalore-560012
- India
| | - P. C. Mishra
- Department of Physics
- Banaras Hindu University
- Varanasi-221005
- India
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14
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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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15
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Appell M, Bosma WB. Assessment of the electronic structure and properties of trichothecene toxins using density functional theory. JOURNAL OF HAZARDOUS MATERIALS 2015; 288:113-123. [PMID: 25698572 DOI: 10.1016/j.jhazmat.2015.01.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 01/17/2015] [Accepted: 01/21/2015] [Indexed: 06/04/2023]
Abstract
A comprehensive quantum chemical study was carried out on 35 type A and B trichothecenes and biosynthetic precursors, including selected derivatives of deoxynivalenol and T-2 toxin. Quantum chemical properties, Natural Bond Orbital (NBO) analysis, and molecular parameters were calculated on structures geometry optimized at the B3LYP/6-311+G** level. Type B trichothecenes possessed significantly larger electrophilicity index compared to the type A trichothecenes studied. Certain hydroxyl groups of deoxynivalenol, nivalenol, and T-2 toxin exhibited considerable rotation during molecular dynamics simulations (5 ps) at the B3LYP/6-31G** level in implicit aqueous solvent. Quantitative structure activity relationship (QSAR) models were developed to evaluate toxicity and detection using genetic algorithm, principal component, and multilinear analyses. The models suggest electronegativity and several 2-dimensional topological descriptors contain important information related to trichothecene cytotoxicity, phytotoxicity, immunochemical detection, and cross-reactivity.
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Affiliation(s)
- Michael Appell
- Bacterial Foodborne Pathogens and Mycology Research USDA, ARS, National Center for Agricultural Utilization Research 1815 N. University St., Peoria, IL 61604, USA.
| | - Wayne B Bosma
- Mund-Lagowski Department of Chemistry and Biochemistry Bradley University 1501 W. Bradley Ave., Peoria, IL 61625, USA.
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Kathuria P, Sharma P, Abendong MN, Wetmore SD. Conformational Preferences of DNA following Damage by Aristolochic Acids: Structural and Energetic Insights into the Different Mutagenic Potential of the ALI and ALII-N6-dA Adducts. Biochemistry 2015; 54:2414-28. [PMID: 25761009 DOI: 10.1021/bi501484m] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Preetleen Kathuria
- Department of Chemistry and
Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
| | - Purshotam Sharma
- Department of Chemistry and
Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
| | - Minette N. Abendong
- Department of Chemistry and
Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
| | - Stacey D. Wetmore
- Department of Chemistry and
Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
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17
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Sharma P, Majdi Yazdi M, Merriman A, Manderville RA, Wetmore SD. Influence of the Linkage Type and Functional Groups in the Carcinogenic Moiety on the Conformational Preferences of Damaged DNA: Structural and Energetic Characterization of Carbon- and Oxygen-Linked C8-Phenolic-Guanine Adducts. Chem Res Toxicol 2015; 28:782-96. [DOI: 10.1021/tx500527p] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Purshotam Sharma
- Department
of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Mohadeseh Majdi Yazdi
- Department
of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Ashlyn Merriman
- Department
of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Richard A. Manderville
- Departments
of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, Canada N1G2W1
| | - Stacey D. Wetmore
- Department
of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
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18
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Bondy GS, Caldwell DS, Aziz SA, Coady LC, Armstrong CL, Curran IHA, Koffman RL, Kapal K, Lefebvre DE, Mehta R. Effects of Chronic Ochratoxin A Exposure on p53 Heterozygous and p53 Homozygous Mice. Toxicol Pathol 2015; 43:715-29. [DOI: 10.1177/0192623314568391] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Exposure to the mycotoxin ochratoxin A (OTA) causes nephropathy in domestic animals and rodents and renal tumors in rodents and poultry. Humans are exposed to OTA by consuming foods made with contaminated cereal grains and other commodities. Management of human health risks due to OTA exposure depends, in part, on establishing a mode of action (MOA) for OTA carcinogenesis. To further investigate OTA’s MOA, p53 heterozygous (p53+/−) and p53 homozygous (p53+/+) mice were exposed to OTA in diet for 26 weeks. The former are susceptible to tumorigenesis upon chronic exposure to genotoxic carcinogens. OTA-induced renal damage but no tumors were observed in either strain, indicating that p53 heterozygosity conferred little additional sensitivity to OTA. Renal changes included dose-dependent increases in cellular proliferation, apoptosis, karyomegaly, and tubular degeneration in proximal tubules, which were consistent with ochratoxicosis. The lowest observed effect level for renal changes in p53+/− and p53+/+ mice was 200 μg OTA/kg bw/day. Based on the lack of tumors and the severity of renal and body weight changes at a maximum tolerated dose, the results were interpreted as suggestive of a primarily nongenotoxic (epigenetic) MOA for OTA carcinogenesis in this mouse model.
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Affiliation(s)
- Genevieve S. Bondy
- Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - Donald S. Caldwell
- Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - Syed A. Aziz
- Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - Laurie C. Coady
- Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - Cheryl L. Armstrong
- Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - Ivan H. A. Curran
- Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | | | - Kamla Kapal
- Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - David E. Lefebvre
- Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - Rekha Mehta
- Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
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19
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Sharma P, Manderville RA, Wetmore SD. Structural and energetic characterization of the major DNA adduct formed from the food mutagen ochratoxin A in the NarI hotspot sequence: influence of adduct ionization on the conformational preferences and implications for the NER propensity. Nucleic Acids Res 2014; 42:11831-45. [PMID: 25217592 PMCID: PMC4191402 DOI: 10.1093/nar/gku821] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The nephrotoxic food mutagen ochratoxin A (OTA) produces DNA adducts in rat kidneys, the major lesion being the C8-linked-2′-deoxyguanosine adduct (OTB-dG). Although research on other adducts stresses the importance of understanding the structure of the associated adducted DNA, site-specific incorporation of OTB-dG into DNA has yet to be attempted. The present work uses a robust computational approach to determine the conformational preferences of OTB-dG in three ionization states at three guanine positions in the NarI recognition sequence opposite cytosine. Representative adducted DNA helices were derived from over 2160 ns of simulation and ranked via free energies. For the first time, a close energetic separation between three distinct conformations is highlighted, which indicates OTA-adducted DNA likely adopts a mixture of conformations regardless of the sequence context. Nevertheless, the preferred conformation depends on the flanking bases and ionization state due to deviations in discrete local interactions at the lesion site. The structural characteristics of the lesion thus discerned have profound implications regarding its repair propensity and mutagenic outcomes, and support recent experiments suggesting the induction of double-strand breaks and deletion mutations upon OTA exposure. This combined structural and energetic characterization of the OTB-dG lesion in DNA will encourage future biochemical experiments on this potentially genotoxic lesion.
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Affiliation(s)
- Purshotam Sharma
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, T1K 3M4, Canada
| | - Richard A Manderville
- Department of Chemistry and Toxicology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, T1K 3M4, Canada
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20
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Wilson KA, Wetmore SD. Complex Conformational Heterogeneity of the Highly Flexible O6-Benzyl-guanine DNA Adduct. Chem Res Toxicol 2014; 27:1310-25. [PMID: 24941023 DOI: 10.1021/tx500178x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Katie A. Wilson
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
| | - Stacey D. Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
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21
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DFT and MD study of the divalent-cation-mediated interaction of ochratoxin A with DNA nucleosides. J Mol Model 2014; 20:2274. [PMID: 24863531 DOI: 10.1007/s00894-014-2274-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 04/24/2014] [Indexed: 01/01/2023]
Abstract
Aptamers are ligand-binding nucleic acids with affinities and selectivities that make them useful for the detection of a variety of compounds, including ochratoxin A. Theoretical methods can be applied to study the recognition interaction between aptamers and the ochratoxin A molecule. In this work, molecular dynamics simulations and quantum chemical calculations performed at the DFT level of theory were used to study the structures and energies of aptamers and aptamer-ochratoxin A complexes. The optimal structures as well as the interaction energies of these structures were elucidated. Divalent cations in the water solvent were shown to be an important influence on the structures and stabilities of the complexes.
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22
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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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