1
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Crisalli AM, Chen YT, Cai A, Li D, Cho BP. Conformation-dependent lesion bypass of bulky arylamine-dG adducts generated from 2-nitrofluorene in epigenetic sequence contexts. Nucleic Acids Res 2023; 51:12043-12053. [PMID: 37953358 PMCID: PMC10711442 DOI: 10.1093/nar/gkad1038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 09/27/2023] [Accepted: 10/24/2023] [Indexed: 11/14/2023] Open
Abstract
Sequence context influences structural characteristics and repair of DNA adducts, but there is limited information on how epigenetic modulation affects conformational heterogeneity and bypass of DNA lesions. Lesions derived from the environmental pollutant 2-nitrofluorene have been extensively studied as chemical carcinogenesis models; they adopt a sequence-dependent mix of two significant conformers: major groove binding (B) and base-displaced stacked (S). We report a conformation-dependent bypass of the N-(2'-deoxyguanosin-8-yl)-7-fluoro-2-aminofluorene (dG-FAF) lesion in epigenetic sequence contexts (d[5'-CTTCTC#G*NCCTCATTC-3'], where C# is C or 5-methylcytosine (5mC), G* is G or G-FAF, and N is A, T, C or G). FAF-modified sequences with a 3' flanking pyrimidine were better bypassed when the 5' base was 5mC, whereas sequences with a 3' purine exhibited the opposite effect. The conformational basis behind these variations differed; for -CG*C- and -CG*T-, bypass appeared to be inversely correlated with population of the duplex-destabilizing S conformer. On the other hand, the connection between conformation and a decrease in bypass for flanking purines in the 5mC sequences relative to C was more complex. It could be related to the emergence of a disruptive non-S/B conformation. The present work provides novel conformational insight into how 5mC influences the bypass efficiency of bulky DNA damage.
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Affiliation(s)
- Alicia M Crisalli
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Yi-Tzai Chen
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Ang Cai
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Bongsup P Cho
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
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2
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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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3
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Cai A, Wilson KA, Patnaik S, Wetmore SD, Cho BP. DNA base sequence effects on bulky lesion-induced conformational heterogeneity during DNA replication. Nucleic Acids Res 2019; 46:6356-6370. [PMID: 29800374 PMCID: PMC6158707 DOI: 10.1093/nar/gky409] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 05/03/2018] [Indexed: 12/11/2022] Open
Abstract
4-Aminobiphenyl (ABP) and its structure analog 2-aminofluorene (AF) are well-known carcinogens. In the present work, an unusual sequence effect in the 5′-CTTCTG1G2TCCTCATTC-3′ DNA duplex is reported for ABP- and AF-modified G. Specifically, the ABP modification at G1 resulted in a mixture of 67% major groove B-type (B) and 33% stacked (S) conformers, while at the ABP modification at G2 exclusively resulted in the B-conformer. The AF modification at G1 and G2 lead to 25%:75% and 83%:17% B:S population ratios, respectively. These differences in preferred conformation are due to an interplay between stabilizing (hydrogen bonding and stacking that is enhanced by lesion planarity) and destabilizing (solvent exposure) forces at the lesion site. Furthermore, while the B-conformer is a thermodynamic stabilizer and the S-conformer is a destabilizer in duplex settings, the situation is reversed at the single strands/double strands (ss/ds) junction. Specifically, the twisted biphenyl is a better stacker at the ss/ds junction than the coplanar AF. Therefore, the ABP modification leads to a stronger strand binding affinity of the ss/ds junction than the AF modification. Overall, the current work provides conformational insights into the role of sequence and lesion effects in modulating DNA replication.
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Affiliation(s)
- Ang Cai
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - Katie A Wilson
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Satyakam Patnaik
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Bongsup P Cho
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA
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4
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Cai A, Bian K, Chen F, Tang Q, Carley R, Li D, Cho BP. Probing the Effect of Bulky Lesion-Induced Replication Fork Conformational Heterogeneity Using 4-Aminobiphenyl-Modified DNA. Molecules 2019; 24:molecules24081566. [PMID: 31009995 PMCID: PMC6514942 DOI: 10.3390/molecules24081566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/14/2019] [Accepted: 04/17/2019] [Indexed: 11/16/2022] Open
Abstract
Bulky organic carcinogens are activated in vivo and subsequently react with nucleobases of cellular DNA to produce adducts. Some of these DNA adducts exist in multiple conformations that are slowly interconverted to one another. Different conformations have been implicated in different mutagenic and repair outcomes. However, studies on the conformation-specific inhibition of replication, which is more relevant to cell survival, are scarce, presumably due to the structural dynamics of DNA lesions at the replication fork. It is difficult to capture the exact nature of replication inhibition by existing end-point assays, which usually detect either the ensemble of consequences of all the conformers or the culmination of all cellular behaviors, such as mutagenicity or survival rate. We previously reported very unusual sequence-dependent conformational heterogeneities involving FABP-modified DNA under different sequence contexts (TG1*G2T [67%B:33%S] and TG1G2*T [100%B], G*, N-(2′-deoxyguanosin-8-yl)-4′-fluoro-4-aminobiphenyl) (Cai et al. Nucleic Acids Research, 46, 6356–6370 (2018)). In the present study, we attempted to correlate the in vitro inhibition of polymerase activity to different conformations from a single FABP-modified DNA lesion. We utilized a combination of surface plasmon resonance (SPR) and HPLC-based steady-state kinetics to reveal the differences in terms of binding affinity and inhibition with polymerase between these two conformers (67%B:33%S and 100%B).
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Affiliation(s)
- Ang Cai
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, USA.
| | - Ke Bian
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, USA.
| | - Fangyi Chen
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, USA.
| | - Qi Tang
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, USA.
| | - Rachel Carley
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, USA.
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, USA.
| | - Bongsup P Cho
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, RI 02881, USA.
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5
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Berger FD, Manderville RA, Sturla SJ. Adduct Fluorescence as a Tool to Decipher Sequence Impact on Frameshift Mutations Mediated by a C-Linked C8-Biphenyl-Guanine Lesion. Chem Res Toxicol 2019; 32:784-791. [PMID: 30785283 DOI: 10.1021/acs.chemrestox.9b00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aromatic chemicals can undergo metabolic activation to afford electrophilic species that react at the C8-site of 2'-deoxyguanosine (dG) to generate bulky C8-dG adducts as a basis of initiating carcinogenesis. These DNA lesions have served as models to understand the mechanism of frameshift mutagenesis, especially within CG-dinucleotide repeat sequences, such as NarI (5'-GGCXCC-3', where X = C8-dG adduct), however there is still limited capacity to predict the likelihood of mutation arising within particular contexts, and hence chemistry-based strategies are needed for probing relationships between nucleic acid sequence and structure with replication errors. In the NarI sequence, certain C8-dG adducts may trigger in the course of DNA synthesis the formation of a slipped mutagenic intermediate (SMI) that contains a two nucleotide (XC) bulge in the template strand that can form upstream of the polymerase active site. This distortion facilitates polymerization but affords a GC dinucleotide deletion product (-2 frameshift mutation). In the current study, incorporating the fluorescent C-linked 4-fluorobiphenyl-dG (FBP-dG) adduct into two 22-mer templates containing CG-dinucleotide repeats ( NarI: 3'-CXCGGC-5' and CG3: 3'-CXCGCG-5', X = FBP-dG) and performing primer extension reactions using DNA polymerase I, Klenow fragment exo- (Kf-) revealed a dramatic sequence-based difference in polymerase bypass efficiency. Primer extension past FBP-dG within the NarI sequence was strongly blocked, whereas Kf- extended the primer past FBP-dG within a CG3 template to afford a full-length product and the GC dinucleotide deletion. To model the nucleotide insertion steps in the fully paired (FP) versus the slipped mutagenic (SM) translesion pathways, adducted template:primer duplexes were constructed and characterized by UV thermal denaturation and fluorescence spectroscopy. The emission intensity of the FBP-dG lesion exhibits sensitivity to SMI formation (turn-on) versus a FP duplex (turn-off), permitting insight into adduct base-pairing within the template:primer duplexes. This fluorescence sensitivity provides a rationale for sequence impact on -2 frameshift mutations mediated by the C-linked FBP-dG lesion.
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Affiliation(s)
- Florence D Berger
- Department of Health Sciences and Technology , ETH Zurich , 8092 Zurich , Switzerland
| | - Richard A Manderville
- Departments of Chemistry and Toxicology , University of Guelph , Guelph , Ontario , Canada N1G 2W1
| | - Shana J Sturla
- Department of Health Sciences and Technology , ETH Zurich , 8092 Zurich , Switzerland
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6
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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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7
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Tang Q, Cai A, Bian K, Chen F, Delaney JC, Adusumalli S, Bach AC, Akhlaghi F, Cho BP, Li D. Characterization of Byproducts from Chemical Syntheses of Oligonucleotides Containing 1-Methyladenine and 3-Methylcytosine. ACS OMEGA 2017; 2:8205-8212. [PMID: 29214236 PMCID: PMC5709782 DOI: 10.1021/acsomega.7b01482] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 11/01/2017] [Indexed: 06/07/2023]
Abstract
Oligonucleotides serve as important tools for biological, chemical, and medical research. The preparation of oligonucleotides through automated solid-phase synthesis is well-established. However, identification of byproducts generated from DNA synthesis, especially from oligonucleotides containing site-specific modifications, is sometimes challenging. Typical high-performance liquid chromatography (HPLC), mass spectrometry (MS), and gel electrophoresis methods alone are not sufficient for characterizing unexpected byproducts, especially for those having identical or very similar molecular weight (MW) to the products. We used a rigorous quality control procedure to characterize byproducts generated during oligonucleotide syntheses: (1) purify oligonucleotides by different HPLC systems; (2) determine exact MW by high-resolution MS; (3) locate modification position by MS/MS or exonuclease digestion with matrix-assisted laser desorption ionization-time of flight analysis; and (4) conduct, where applicable, enzymatic assays. We applied these steps to characterize byproducts in the syntheses of oligonucleotides containing biologically important methyl DNA adducts 1-methyladenine (m1A) and 3-methylcytosine (m3C). In m1A synthesis, we differentiated a regioisomeric byproduct 6-methyladenine, which possesses a MW identical to uncharged m1A. As for m3C, we identified a deamination byproduct 3-methyluracil, which is only 1 Da greater than uncharged m3C in the ∼4900 Da context. The detection of these byproducts would be very challenging if the abovementioned procedure was not adopted.
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Affiliation(s)
- Qi Tang
- Department
of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, Rhode Island 02881, United States
| | - Ang Cai
- Department
of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, Rhode Island 02881, United States
| | - Ke Bian
- Department
of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, Rhode Island 02881, United States
| | - Fangyi Chen
- Department
of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, Rhode Island 02881, United States
| | - James C. Delaney
- Visterra
Inc., One Kendall Square, Cambridge, Massachusetts 02139, United States
| | - Sravani Adusumalli
- Department
of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, Rhode Island 02881, United States
| | - Alvin C. Bach
- Department
of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, Rhode Island 02881, United States
| | - Fatemeh Akhlaghi
- Department
of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, Rhode Island 02881, United States
| | - Bongsup P. Cho
- Department
of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, Rhode Island 02881, United States
| | - Deyu Li
- Department
of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, 7 Greenhouse Road, Kingston, Rhode Island 02881, United States
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8
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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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9
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Li W, Li Y, Liu Z, Lin B, Yi H, Xu F, Nie Z, Yao S. Insight into G-quadruplex-hemin DNAzyme/RNAzyme: adjacent adenine as the intramolecular species for remarkable enhancement of enzymatic activity. Nucleic Acids Res 2016; 44:7373-84. [PMID: 27422869 PMCID: PMC5009756 DOI: 10.1093/nar/gkw634] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/29/2016] [Indexed: 01/15/2023] Open
Abstract
G-quadruplex (G4) with stacked G-tetrads structure is able to bind hemin (iron (III)-protoporphyrin IX) to form a unique type of DNAzyme/RNAzyme with peroxidase-mimicking activity, which has been widely employed in multidisciplinary fields. However, its further applications are hampered by its relatively weak activity compared with protein enzymes. Herein, we report a unique intramolecular enhancement effect of the adjacent adenine (EnEAA) at 3' end of G4 core sequences that significantly improves the activity of G4 DNAzymes. Through detailed investigations of the EnEAA, the added 3' adenine was proved to accelerate the compound I formation in catalytic cycle and thus improve the G4 DNAzyme activity. EnEAA was found to be highly dependent on the unprotonated state of the N1 of adenine, substantiating that adenine might function as a general acid-base catalyst. Further adenine analogs analysis supported that both N1 and exocyclic 6-amino groups in adenine played key role in the catalysis. Moreover, we proved that EnEAA was generally applicable for various parallel G-quadruplex structures and even G4 RNAzyme. Our studies implied that adenine might act analogously as the distal histidine in protein peroxidases, which shed light on the fundamental understanding and rational design of G4 DNAzyme/RNAzyme catalysts with enhanced functions.
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Affiliation(s)
- Wang Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
| | - Yong Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
| | - Zhuoliang Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
| | - Bin Lin
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering & Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, P. R. China
| | - Haibo Yi
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
| | - Feng Xu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
| | - Zhou Nie
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
| | - Shouzhuo Yao
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
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10
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Xu L, Cho BP. Conformational Insights into the Mechanism of Acetylaminofluorene-dG-Induced Frameshift Mutations in the NarI Mutational Hotspot. Chem Res Toxicol 2016; 29:213-26. [PMID: 26733364 DOI: 10.1021/acs.chemrestox.5b00484] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Frameshift mutagenesis encompasses the gain or loss of DNA base pairs, resulting in altered genetic outcomes. The NarI restriction site sequence 5'-G1G2CG3CX-3' in Escherichia coli is a well-known mutational hotspot, in which lesioning of acetylaminofluorene (AAF) at G3* induces a greater -2 deletion frequency than that at other guanine sites. Its mutational efficiency is modulated by the nature of the nucleotide in the X position (C ∼ A > G ≫ T). Here, we conducted a series of polymerase-free solution experiments that examine the conformational and thermodynamic basis underlying the propensity of adducted G3 to form a slipped mutagenic intermediate (SMI) and its sequence dependence during translesion synthesis (TLS). Instability of the AAF-dG3:dC pair at the replication fork promoted slippage to form a G*C bulge-out SMI structure, consisting of S- ("lesion stacked") and B-SMI ("lesion exposed") conformations, with conformational rigidity increasing as a function of primer elongation. We found greater stability of the S- compared to the B-SMI conformer throughout TLS. The dependence of their population ratios was determined by the 3'-next flanking base X at fully elongated bulge structures, with 59% B/41% S and 86% B/14% S for the dC and dT series, respectively. These results indicate the importance of direct interactions of the hydrophobic AAF lesion with the 3'-next flanking base pair and its stacking fit within the -2 bulge structure. A detailed conformational understanding of the SMI structures and their sequence dependence may provide a useful model for DNA polymerase complexes.
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Affiliation(s)
- Lifang Xu
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
| | - Bongsup P Cho
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
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11
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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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