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Bellamri M, Walmsley SJ, Turesky RJ. Metabolism and biomarkers of heterocyclic aromatic amines in humans. Genes Environ 2021; 43:29. [PMID: 34271992 PMCID: PMC8284014 DOI: 10.1186/s41021-021-00200-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/27/2021] [Indexed: 12/15/2022] Open
Abstract
Heterocyclic aromatic amines (HAAs) form during the high-temperature cooking of meats, poultry, and fish. Some HAAs also arise during the combustion of tobacco. HAAs are multisite carcinogens in rodents, inducing cancer of the liver, gastrointestinal tract, pancreas, mammary, and prostate glands. HAAs undergo metabolic activation by N-hydroxylation of the exocyclic amine groups to produce the proposed reactive intermediate, the heteroaryl nitrenium ion, which is the critical metabolite implicated in DNA damage and genotoxicity. Humans efficiently convert HAAs to these reactive intermediates, resulting in HAA protein and DNA adduct formation. Some epidemiologic studies have reported an association between frequent consumption of well-done cooked meats and elevated cancer risk of the colorectum, pancreas, and prostate. However, other studies have reported no associations between cooked meat and these cancer sites. A significant limitation in epidemiology studies assessing the role of HAAs and cooked meat in cancer risk is their reliance on food frequency questionnaires (FFQ) to gauge HAA exposure. FFQs are problematic because of limitations in self-reported dietary history accuracy, and estimating HAA intake formed in cooked meats at the parts-per-billion level is challenging. There is a critical need to establish long-lived biomarkers of HAAs for implementation in molecular epidemiology studies designed to assess the role of HAAs in health risk. This review article highlights the mechanisms of HAA formation, mutagenesis and carcinogenesis, the metabolism of several prominent HAAs, and the impact of critical xenobiotic-metabolizing enzymes on biological effects. The analytical approaches that have successfully biomonitored HAAs and their biomarkers for molecular epidemiology studies are presented.
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Affiliation(s)
- Medjda Bellamri
- Masonic Cancer Center and Department of Medicinal Chemistry, Cancer and Cardiovascular Research Building, University of Minnesota, 2231 6th Street, Minneapolis, MN, 55455, USA.,Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Scott J Walmsley
- Masonic Cancer Center and Department of Medicinal Chemistry, Cancer and Cardiovascular Research Building, University of Minnesota, 2231 6th Street, Minneapolis, MN, 55455, USA.,Institute of Health Informatics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Robert J Turesky
- Masonic Cancer Center and Department of Medicinal Chemistry, Cancer and Cardiovascular Research Building, University of Minnesota, 2231 6th Street, Minneapolis, MN, 55455, USA. .,Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN, 55455, USA.
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Okolotowicz KJ, Bushway P, Lanier M, Gilley C, Mercola M, Cashman JR. 1,5-Disubstituted benzimidazoles that direct cardiomyocyte differentiation from mouse embryonic stem cells. Bioorg Med Chem 2015; 23:5282-92. [PMID: 26278027 DOI: 10.1016/j.bmc.2015.07.073] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 07/23/2015] [Accepted: 07/30/2015] [Indexed: 12/13/2022]
Abstract
Cardiomyopathy is the leading cause of death worldwide. Despite progress in medical treatments, heart transplantation is one of the only current options for those with infarcted heart muscle. Stem cell differentiation technology may afford cell-based therapeutics that may lead to the generation of new, healthy heart muscle cells from undifferentiated stem cells. Our approach is to use small molecules to stimulate stem cell differentiation. Herein, we describe a novel class of 1,5-disubstituted benzimidazoles that induce differentiation of stem cells into cardiac cells. We report on the evaluation in vitro for cardiomyocyte differentiation and describe structure-activity relationship results that led to molecules with drug-like properties. The results of this study show the promise of small molecules to direct stem cell lineage commitment, to probe signaling pathways and to develop compounds for the stimulation of stem cells to repair damaged heart tissue.
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Affiliation(s)
- Karl J Okolotowicz
- Human BioMolecular Research Institute, 5310 Eastgate Mall, San Diego, CA 92121, USA.
| | - Paul Bushway
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive MC 0695, La Jolla, CA 92093-0695, USA
| | - Marion Lanier
- Human BioMolecular Research Institute, 5310 Eastgate Mall, San Diego, CA 92121, USA
| | - Cynthia Gilley
- Human BioMolecular Research Institute, 5310 Eastgate Mall, San Diego, CA 92121, USA
| | - Mark Mercola
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive MC 0695, La Jolla, CA 92093-0695, USA
| | - John R Cashman
- Human BioMolecular Research Institute, 5310 Eastgate Mall, San Diego, CA 92121, USA
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Stavros KM, Hawkins EK, Rizzo CJ, Stone MP. Base-Displaced Intercalated Conformation of the 2-Amino-3-methylimidazo[4,5-f]quinoline N(2)-dG DNA Adduct Positioned at the Nonreiterated G(1) in the NarI Restriction Site. Chem Res Toxicol 2015; 28:1455-68. [PMID: 26083477 PMCID: PMC4511292 DOI: 10.1021/acs.chemrestox.5b00140] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
The
conformation of an N2-dG adduct
arising from the heterocyclic amine 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), a potent food mutagen, was determined
in 5′-d(C1T2C3X4G5C6G7C8C9A10T11C12)-3′:5′-d(G13A14T15G16G17C18G19C20C21G22A23G24)-3′; X = N2-dG-IQ, in which the modified nucleotide X4 corresponds to G1 in the 5′-d(G1G2CG3CC)-3′ NarI restriction endonuclease site. Circular dichroism (CD) revealed
blue shifts relative to the unmodified duplex, consistent with adduct-induced
twisting, and a hypochromic effect for the IQ absorbance in the near
UV region. NMR revealed that the N2-dG-IQ
adduct adopted a base-displaced intercalated conformation in which
the modified guanine remained in the anti conformation
about the glycosidic bond, the IQ moiety intercalated into the duplex,
and the complementary base C21 was displaced into the major
groove. The processing of the N2-dG-IQ
lesion by hpol η is sequence-dependent; when placed at the reiterated
G3 position, but not at the G1 position, this
lesion exhibits a propensity for frameshift replication [Choi, J.
Y., et al. (2006) J. Biol. Chem., 281, 25297–25306]. The structure of the N2-dG-IQ adduct at the nonreiterated G1 position
was compared to that of the same adduct placed at the G3 position [Stavros, K. M., et al. (2014) Nucleic Acids Res., 42, 3450–3463]. CD indicted minimal spectral
differences between the G1 vs G3N2-dG-IQ adducts. NMR indicated that the N2-dG-IQ adduct exhibited similar base-displaced intercalated
conformations at both the G1 and G3 positions.
This result differed as compared to the corresponding C8-dG-IQ adducts
placed at the same positions. The C8-dG-IQ adduct adopted a minor
groove conformation when placed at position G1 but a base-displaced
intercalated conformation when placed at position G3 in
the NarI sequence. The present studies suggest that
differences in lesion bypass by hpol η may be mediated by differences
in the 3′-flanking sequences, perhaps modulating the ability
to accommodate transient strand slippage intermediates.
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Affiliation(s)
- Kallie M Stavros
- †Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235-1822, United States
| | | | - Carmelo J Rizzo
- †Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235-1822, United States
| | - Michael P Stone
- †Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235-1822, United States
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Stavros KM, Hawkins EK, Rizzo CJ, Stone MP. Base-displaced intercalation of the 2-amino-3-methylimidazo[4,5-f]quinolone N2-dG adduct in the NarI DNA recognition sequence. Nucleic Acids Res 2014; 42:3450-63. [PMID: 24366876 PMCID: PMC3950664 DOI: 10.1093/nar/gkt1109] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 10/18/2013] [Accepted: 10/21/2013] [Indexed: 12/14/2022] Open
Abstract
2-Amino-3-methylimidazo[4,5-f]quinolone (IQ), a heterocyclic amine found in cooked meats, undergoes bioactivation to a nitrenium ion, which alkylates guanines at both the C8-dG and N2-dG positions. The conformation of a site-specific N2-dG-IQ adduct in an oligodeoxynucleotide duplex containing the iterated CG repeat restriction site of the NarI endonuclease has been determined. The IQ moiety intercalates, with the IQ H4a and CH3 protons facing the minor groove, and the IQ H7a, H8a and H9a protons facing the major groove. The adducted dG maintains the anti-conformation about the glycosyl bond. The complementary dC is extruded into the major groove. The duplex maintains its thermal stability, which is attributed to stacking between the IQ moiety and the 5'- and 3'-neighboring base pairs. This conformation is compared to that of the C8-dG-IQ adduct in the same sequence, which also formed a 'base-displaced intercalated' conformation. However, the C8-dG-IQ adopted the syn conformation placing the Watson-Crick edge of the modified dG into the major groove. In addition, the C8-dG-IQ adduct was oriented with the IQ CH3 group and H4a and H5a facing the major groove. These differences may lead to differential processing during DNA repair and replication.
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Affiliation(s)
| | | | | | - Michael P. Stone
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235-1822, USA
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5
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Palladium-Catalyzed sp2 C–N Bond Forming Reactions: Recent Developments and Applications. TOP ORGANOMETAL CHEM 2012. [DOI: 10.1007/3418_2012_56] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Rauws TRM, Maes BUW. Transition metal-catalyzed N-arylations of amidines and guanidines. Chem Soc Rev 2012; 41:2463-97. [DOI: 10.1039/c1cs15236j] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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8
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Wong OY, Mulcrone AE, Silverman SK. DNA-catalyzed reductive amination. Angew Chem Int Ed Engl 2011; 50:11679-84. [PMID: 21994131 DOI: 10.1002/anie.201104976] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 09/22/2011] [Indexed: 11/12/2022]
Affiliation(s)
- On Yi Wong
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
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Thomson PF, Lagisetty P, Balzarini J, De Clercq E, Lakshman MK. Palladium-Catalyzed Aryl Amination Reactions of 6-Bromo- and 6-Chloropurine Nucleosides. Adv Synth Catal 2010; 352:1728-1735. [PMID: 21818182 PMCID: PMC3148652 DOI: 10.1002/adsc.200900728] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Palladium‐catalyzed C—N bond forming reactions of 6‐bromo‐ as well as 6‐chloropurine ribonucleosides and the 2′‐deoxy analogues with arylamines are described. Efficient conversions were observed with palladium(II) acetate/Xantphos/cesium carbonate, in toluene at 100 °C. Reactions of the bromonucleoside derivatives could be conducted at a lowered catalytic loading [5 mol% Pd(OAc)2/7.5 mol% Xantphos], whereas good product yields were obtained with a higher catalyst load [10 mol% Pd(OAc)2/15 mol% Xantphos] when the chloro analogue was employed. Among the examples evaluated, silyl protection for the hydroxy groups appears better as compared to acetyl. The methodology has been evaluated via reactions with a variety of arylamines and by synthesis of biologically relevant deoxyadenosine and adenosine dimers. This is the first detailed analysis of aryl amination reactions of 6‐chloropurine nucleosides, and comparison of the two halogenated nucleoside substrates.
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Affiliation(s)
- Paul F Thomson
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, New York 10031, U.S.A
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Pratap R, Parrish D, Gunda P, Venkataraman D, Lakshman MK. Influence of Biaryl Phosphine Structure on C−N and C−C Bond Formation. J Am Chem Soc 2009; 131:12240-9. [DOI: 10.1021/ja902679b] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ramendra Pratap
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, New York 10031, Naval Research Laboratory, Code 6030, 4555 Overlook Avenue, Washington, D.C. 20375, and Department of Chemistry, University of Massachusetts Amherst, 710 North Pleasant Street, Amherst, Massachusetts 01003
| | - Damon Parrish
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, New York 10031, Naval Research Laboratory, Code 6030, 4555 Overlook Avenue, Washington, D.C. 20375, and Department of Chemistry, University of Massachusetts Amherst, 710 North Pleasant Street, Amherst, Massachusetts 01003
| | - Padmaja Gunda
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, New York 10031, Naval Research Laboratory, Code 6030, 4555 Overlook Avenue, Washington, D.C. 20375, and Department of Chemistry, University of Massachusetts Amherst, 710 North Pleasant Street, Amherst, Massachusetts 01003
| | - D. Venkataraman
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, New York 10031, Naval Research Laboratory, Code 6030, 4555 Overlook Avenue, Washington, D.C. 20375, and Department of Chemistry, University of Massachusetts Amherst, 710 North Pleasant Street, Amherst, Massachusetts 01003
| | - Mahesh K. Lakshman
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, New York 10031, Naval Research Laboratory, Code 6030, 4555 Overlook Avenue, Washington, D.C. 20375, and Department of Chemistry, University of Massachusetts Amherst, 710 North Pleasant Street, Amherst, Massachusetts 01003
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11
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Stover JS, Rizzo CJ. Synthesis of oligonucleotides containing the N2-deoxyguanosine adduct of the dietary carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline. Chem Res Toxicol 2007; 20:1972-9. [PMID: 17914884 PMCID: PMC3138521 DOI: 10.1021/tx7002867] [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: 12/15/2022]
Abstract
2-amino-3-methylimidazo[4,5-f]quinoline (IQ) is a highly mutagenic heterocyclic amine formed in all cooked meats. IQ has been found to be a potent inducer of frameshift mutations in bacteria and carcinogenic in laboratory animals. Upon metabolic activation, IQ forms covalent adducts at the C8- and N2-positions of deoxyguanosine with a relative ratio of up to approximately 4:1. We have previously incorporated the major dGuo-C8-IQ adduct into oligonucleotides through the corresponding phosphoramidite reagent. We report here the sequence-specific synthesis of oligonucleotides containing the minor dGuo-N2-IQ adduct. Thermal melting analysis revealed that the dGuo-N2-IQ adduct significantly destabilizes duplex DNA.
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Affiliation(s)
| | - Carmelo J. Rizzo
- To whom correspondence should be addressed. Tel: 615-322-6100. Fax: 615-343-1234.
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12
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Champeil E, Pradhan P, Lakshman MK. Palladium-catalyzed synthesis of nucleoside adducts from bay- and fjord-region diol epoxides. J Org Chem 2007; 72:5035-45. [PMID: 17559269 PMCID: PMC2548296 DOI: 10.1021/jo070204z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Palladium-catalyzed C-N bond formation has been utilized to synthesize covalent 2'-deoxyadenosine (dA) and 2'-deoxyguanosine (dG) adducts of benzo[a]pyrene (BaP) series 1 (syn) and benzo[c]phenanthrene (BcPh) series 2 (anti) diol epoxides. For this, (+/-)-10 alpha-amino-7 beta,8 alpha,9 beta-trisbenzoyloxy-7,8,9,10-tetrahydro BaP and (+/-)-1 beta-amino-2 alpha,3 alpha,4 beta-trisbenzoyloxy-1,2,3,4-tetrahydro BcPh were coupled with 6-halo-9-[3,5-bis-O-(tert-butyldimethylsilyl)-beta-D-erythro-pentofuranosyl]purine and O6-benzyl-3',5'-bis-O-(tert-butyldimethylsilyl)-2-bromo-2'-deoxyinosine, using a (+/-)-BINAP-Pd complex and Cs2CO3. For the synthesis of the dA adducts, both the 6-chloro- as well as the 6-bromopurine nucleoside derivatives were analyzed for the C-N coupling reaction with the hydrocarbon amino tribenzoates. With the BaP amino tribenzoate, the 6-chloronucleoside provided satisfactory results, whereas the 6-bromo analogue proved to be superior with the BcPh amino tribenzoate. Overall, lower yields of the dA adducts were obtained with the more hindered fjord-region BcPh amino tribenzoate as compared to the bay-region BaP amino tribenzoate. In contrast to reactions leading to the dA adducts, the C-N reactions of both BaP and BcPh amino tribenzoates with the 2-bromo-2'-deoxyinosine derivative proceeded in comparable yields. This seems to indicate that such Pd-catalyzed adduct forming reactions at the C-6 position may be influenced by steric constraints of the amine component, whereas those at the C-2 position are less sensitive. Diastereomeric adduct pairs were separated and characterized by spectral methods and by comparisons to adducts produced by direct displacement reactions as well as those formed from DNA alkylation by diol epoxides.
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Affiliation(s)
| | | | - Mahesh K. Lakshman
- *Address correspondence to M.K.L. Tel: (212) 650-7835, fax: (212) 650-6107
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13
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Stover JS, Chowdhury G, Zang H, Guengerich FP, Rizzo CJ. Translesion synthesis past the C8- and N2-deoxyguanosine adducts of the dietary mutagen 2-Amino-3-methylimidazo[4,5-f]quinoline in the NarI recognition sequence by prokaryotic DNA polymerases. Chem Res Toxicol 2007; 19:1506-17. [PMID: 17112239 PMCID: PMC3150502 DOI: 10.1021/tx0601455] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) is found in cooked meats and forms DNA adducts at the C8- and N2-positions of dGuo after appropriate activation. IQ is a potent inducer of frameshift mutations in bacteria and is carcinogenic in laboratory animals. We have incorporated both IQ-adducts into the G1- and G3-positions of the NarI recognition sequence (5'-G1G2CG3CC-3'), which is a hotspot for arylamine modification. The in vitro replication of the oligonucleotides was examined with Escherichia coli pol I Klenow fragment exo-, E. coli pol II exo-, and Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4), and the extension products were sequenced by tandem mass spectrometry. Replication of the C8-adduct at the G3-position resulted in two-base deletions with all three polymerases, whereas error-free bypass and extension was observed at the G1-position. The N2-adduct was bypassed and extended by all three polymerases when positioned at the G1-position, and the error-free product was observed. The N2-adduct at the G3-position was more blocking and was bypassed and extended only by Dpo4 to produce an error-free product. These results indicate that the replication of the IQ-adducts of dGuo is strongly influenced by the local sequence and the regioisomer of the adduct. These results also suggest a possible role for pol II and IV in the error-prone bypass of the C8-IQ-adduct leading to frameshift mutations in reiterated sequences, whereas noniterated sequences result in error-free bypass.
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Affiliation(s)
| | | | | | | | - Carmelo J. Rizzo
- Corresponding author. Tel.: (615) 322-6100; fax: (615) 343-1234;
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Takamura-Enya T, Enomoto S, Wakabayashi K. Palladium-catalyzed direct N-arylation of nucleosides, nucleotides, and oligonucleotides for efficient preparation of dG-N2 adducts with carcinogenic amino-/nitroarenes. J Org Chem 2007; 71:5599-606. [PMID: 16839139 DOI: 10.1021/jo0605243] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A method for direct palladium-catalyzed N-arylation reaction of nucleobases was developed for the convenient synthesis of DNA adducts with carcinogenic compounds. Using xantphos as the phosphine ligand and tetraethylammonium fluoride as the base in DMSO, several o-iodonitroarenes could be efficiently coupled with 2'-deoxyguanosine, 2'-deoxyadenosine, and 2'-deoxycytidine. The presence of a 3'-phosphate group in the deoxyribose moiety was found to be compatible with this N-arylation reaction; further, oligonucleotides could serve as substrates. The facile nitroreduction of the coupling compounds (12) yielded 2'-deoxyguanosin-N2-ylarylamine adducts, which are known to be biologically important. Compound 12 was easily converted to phosphoramidite derivatives, allowing the preparation of site-specific modified oligonucleotides with arylamine after the nitroreduction.
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Affiliation(s)
- Takeji Takamura-Enya
- Cancer Prevention Basic Research Project, National Cancer Centre Research Institute, Tokyo 104-0045, Japan.
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16
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Ngassa FN, Dekorver KA, Melistas TS, Yeh EAH, Lakshman MK. Pd−Xantphos-Catalyzed Direct Arylation of Nucleosides. Org Lett 2006; 8:4613-6. [PMID: 16986963 DOI: 10.1021/ol0619516] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Direct arylation of the exocyclic amino groups of nucleosides represents a simple approach to N-aryl nucleoside derivatives. To date, one limitation has been that only electron-deficient aryl bromides and triflates possessed adequate reactivity for efficient, direct N-arylation of nucleosides. We demonstrate herein that Pd-Xantphos catalytic systems lead to successful N-arylation of suitably protected 2'-deoxyadenosine and 2'-deoxyguanosine with a wide range of aryl bromides.
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Affiliation(s)
- Felix N Ngassa
- Department of Chemistry, Grand Valley State University, Allendale, Michigan 49401, USA.
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17
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Choi JY, Stover JS, Angel KC, Chowdhury G, Rizzo CJ, Guengerich FP. Biochemical basis of genotoxicity of heterocyclic arylamine food mutagens: Human DNA polymerase eta selectively produces a two-base deletion in copying the N2-guanyl adduct of 2-amino-3-methylimidazo[4,5-f]quinoline but not the C8 adduct at the NarI G3 site. J Biol Chem 2006; 281:25297-306. [PMID: 16835218 DOI: 10.1074/jbc.m605699200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heterocyclic arylamines are highly mutagenic and cause tumors in animal models. The mutagenicity is attributed to the C8- and N2-G adducts, the latter of which accumulates due to slower repair. The C8- and N 2-G adducts derived from 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) were placed at the G1 and G3 sites of the NarI sequence, in which the G3 site is an established hot spot for frameshift mutation with the model arylamine derivative 2-acetylaminofluorene but G1 is not. Human DNA polymerase (pol) eta extended primers beyond template G-IQ adducts better than did pol kappa and much better than pol iota or delta. In 1-base incorporation studies, pol eta inserted C and A, pol iota inserted T, and pol kappa inserted G. Steady-state kinetic parameters were measured for these dNTPs opposite the C8- and N 2-IQ adducts at both sites, being most favorable for pol eta. Mass spectrometry of pol eta extension products revealed a single major product in each of four cases; with the G1 and G3 C8-IQ adducts, incorporation was largely error-free. With the G3 N 2-IQ adduct, a -2 deletion occurred at the site of the adduct. With the G1 N 2-IQ adduct, the product was error-free at the site opposite the base and then stalled. Thus, the pol eta products yielded frame-shifts with the N 2 but not the C8 IQ adducts. We show a role for pol eta and the complexity of different chemical adducts of IQ, DNA position, and DNA polymerases.
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Affiliation(s)
- Jeong-Yun Choi
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232-0146, USA
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Hoadley KA, Purtha WE, Wolf AC, Flynn-Charlebois A, Silverman SK. Zn2+-dependent deoxyribozymes that form natural and unnatural RNA linkages. Biochemistry 2005; 44:9217-31. [PMID: 15966746 PMCID: PMC1586068 DOI: 10.1021/bi050146g] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report Zn(2+)-dependent deoxyribozymes that ligate RNA. The DNA enzymes were identified by in vitro selection and ligate RNA with k(obs) up to 0.5 min(-)(1) at 1 mM Zn(2+) and 23 degrees C, pH 7.9, which is substantially faster than our previously reported Mg(2+)-dependent deoxyribozymes. Each new Zn(2+)-dependent deoxyribozyme mediates the reaction of a specific nucleophile on one RNA substrate with a 2',3'-cyclic phosphate on a second RNA substrate. Some of the Zn(2+)-dependent deoxyribozymes create native 3'-5' RNA linkages (with k(obs) up to 0.02 min(-)(1)), whereas all of our previous Mg(2+)-dependent deoxyribozymes that use a 2',3'-cyclic phosphate create non-native 2'-5' RNA linkages. On this basis, Zn(2+)-dependent deoxyribozymes have promise for synthesis of native 3'-5'-linked RNA using 2',3'-cyclic phosphate RNA substrates, although these particular Zn(2+)-dependent deoxyribozymes are likely not useful for this practical application. Some of the new Zn(2+)-dependent deoxyribozymes instead create non-native 2'-5' linkages, just like their Mg(2+) counterparts. Unexpectedly, other Zn(2+)-dependent deoxyribozymes synthesize one of three unnatural linkages that are formed upon the reaction of an RNA nucleophile other than a 5'-hydroxyl group. Two of these unnatural linkages are the 3'-2' and 2'-2' linear junctions created when the 2'-hydroxyl of the 5'-terminal guanosine of one RNA substrate attacks the 2',3'-cyclic phosphate of the second RNA substrate. The third unnatural linkage is a branched RNA that results from attack of a specific internal 2'-hydroxyl of one RNA substrate at the 2',3'-cyclic phosphate. When compared with the consistent creation of 2'-5' linkages by Mg(2+)-dependent ligation, formation of this variety of RNA ligation products by Zn(2+)-dependent deoxyribozymes highlights the versatility of transition metals such as Zn(2+) for mediating nucleic acid catalysis.
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Affiliation(s)
| | | | | | | | - Scott K. Silverman
- * Corresponding author. Phone: (217) 244-4489. Fax: (217) 244-8024. E-mail:
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