Other search tools

About this data

The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.

If you have any questions or comments, please contact us.

Results: 1 to 10 of 24

Publication Record

Connections

Polymerase Bypass of N(6)-Deoxyadenosine Adducts Derived from Epoxide Metabolites of 1,3-Butadiene.
Kotapati S, Wickramaratne S, Esades A, Boldry EJ, Quirk Dorr D, Pence MG, Guengerich FP, Tretyakova NY
(2015) Chem Res Toxicol 28: 1496-507
MeSH Terms: Butadienes, Chromatography, High Pressure Liquid, DNA, DNA Adducts, DNA Primers, DNA Replication, DNA-Directed DNA Polymerase, Deoxyadenosines, Epoxy Compounds, Humans, Kinetics, Oligodeoxyribonucleotides, Spectrometry, Mass, Electrospray Ionization
Show Abstract · Added March 14, 2018
N(6)-(2-Hydroxy-3-buten-1-yl)-2'-deoxyadenosine (N(6)-HB-dA I) and N(6),N(6)-(2,3-dihydroxybutan-1,4-diyl)-2'-deoxyadenosine (N(6),N(6)-DHB-dA) are exocyclic DNA adducts formed upon alkylation of the N(6) position of adenine in DNA by epoxide metabolites of 1,3-butadiene (BD), a common industrial and environmental chemical classified as a human and animal carcinogen. Since the N(6)-H atom of adenine is required for Watson-Crick hydrogen bonding with thymine, N(6)-alkylation can prevent adenine from normal pairing with thymine, potentially compromising the accuracy of DNA replication. To evaluate the ability of BD-derived N(6)-alkyladenine lesions to induce mutations, synthetic oligodeoxynucleotides containing site-specific (S)-N(6)-HB-dA I and (R,R)-N(6),N(6)-DHB-dA adducts were subjected to in vitro translesion synthesis in the presence of human DNA polymerases β, η, ι, and κ. While (S)-N(6)-HB-dA I was readily bypassed by all four enzymes, only polymerases η and κ were able to carry out DNA synthesis past (R,R)-N(6),N(6)-DHB-dA. Steady-state kinetic analyses indicated that all four DNA polymerases preferentially incorporated the correct base (T) opposite (S)-N(6)-HB-dA I. In contrast, hPol β was completely blocked by (R,R)-N(6),N(6)-DHB-dA, while hPol η and κ inserted A, G, C, or T opposite the adduct with similar frequency. HPLC-ESI-MS/MS analysis of primer extension products confirmed that while translesion synthesis past (S)-N(6)-HB-dA I was mostly error-free, replication of DNA containing (R,R)-N(6),N(6)-DHB-dA induced significant numbers of A, C, and G insertions and small deletions. These results indicate that singly substituted (S)-N(6)-HB-dA I lesions are not miscoding, but that exocyclic (R,R)-N(6),N(6)-DHB-dA adducts are strongly mispairing, probably due to their inability to form stable Watson-Crick pairs with dT.
0 Communities
1 Members
0 Resources
13 MeSH Terms
Major groove orientation of the (2S)-N(6)-(2-hydroxy-3-buten-1-yl)-2'-deoxyadenosine DNA adduct induced by 1,2-epoxy-3-butene.
Kowal EA, Wickramaratne S, Kotapati S, Turo M, Tretyakova N, Stone MP
(2014) Chem Res Toxicol 27: 1675-86
MeSH Terms: Alkylation, Butadienes, DNA, DNA Adducts, Deoxyadenosines, Epoxy Compounds, Humans, Molecular Dynamics Simulation, Nuclear Magnetic Resonance, Biomolecular, Nucleic Acid Conformation, Nucleic Acid Denaturation, Oligodeoxyribonucleotides, Stereoisomerism, Transition Temperature, ras Proteins
Show Abstract · Added January 20, 2015
1,3-Butadiene (BD) is an environmental and occupational toxicant classified as a human carcinogen. It is oxidized by cytochrome P450 monooxygenases to 1,2-epoxy-3-butene (EB), which alkylates DNA. BD exposures lead to large numbers of mutations at A:T base pairs even though alkylation of guanines is more prevalent, suggesting that one or more adenine adducts of BD play a role in BD-mediated genotoxicity. However, the etiology of BD-mediated genotoxicity at adenine remains poorly understood. EB alkylates the N(6) exocyclic nitrogen of adenine to form N(6)-(hydroxy-3-buten-1-yl)-2'-dA ((2S)-N(6)-HB-dA) adducts ( Tretyakova , N. , Lin , Y. , Sangaiah , R. , Upton , P. B. , and Swenberg , J. A. ( 1997 ) Carcinogenesis 18 , 137 - 147 ). The structure of the (2S)-N(6)-HB-dA adduct has been determined in the 5'-d(C(1)G(2)G(3)A(4)C(5)Y(6)A(7)G(8)A(9)A(10)G(11))-3':5'-d(C(12)T(13)T(14)C(15)T(16)T(17)G(18)T(19) C(20)C(21)G(22))-3' duplex [Y = (2S)-N(6)-HB-dA] containing codon 61 (underlined) of the human N-ras protooncogene, from NMR spectroscopy. The (2S)-N(6)-HB-dA adduct was positioned in the major groove, such that the butadiene moiety was oriented in the 3' direction. At the Cα carbon, the methylene protons of the modified nucleobase Y(6) faced the 5' direction, which placed the Cβ carbon in the 3' direction. The Cβ hydroxyl group faced toward the solvent, as did carbons Cγ and Cδ. The Cβ hydroxyl group did not form hydrogen bonds with either T(16) O(4) or T(17) O(4). The (2S)-N(6)-HB-dA nucleoside maintained the anti conformation about the glycosyl bond, and the modified base retained Watson-Crick base pairing with the complementary base (T(17)). The adduct perturbed stacking interactions at base pairs C(5):G(18), Y(6):T(17), and A(7):T(16) such that the Y(6) base did not stack with its 5' neighbor C(5), but it did with its 3' neighbor A(7). The complementary thymine T(17) stacked well with both 5' and 3' neighbors T(16) and G(18). The presence of the (2S)-N(6)-HB-dA resulted in a 5 °C reduction in the Tm of the duplex, which is attributed to less favorable stacking interactions and adduct accommodation in the major groove.
0 Communities
1 Members
0 Resources
15 MeSH Terms
In vivo roles of conjugation with glutathione and O6-alkylguanine DNA-alkyltransferase in the mutagenicity of the bis-electrophiles 1,2-dibromoethane and 1,2,3,4-diepoxybutane in mice.
Cho SH, Guengerich FP
(2013) Chem Res Toxicol 26: 1765-74
MeSH Terms: Animals, Butadienes, Buthionine Sulfoximine, Chromatography, High Pressure Liquid, DNA Adducts, DNA Mutational Analysis, Epoxy Compounds, Ethylene Dibromide, Glutathione, Glutathione Transferase, Guanine, Liver, Male, Mice, Mice, Transgenic, Mutagenicity Tests, Mutation, Mutation Rate, O(6)-Methylguanine-DNA Methyltransferase, Spectrometry, Mass, Electrospray Ionization
Show Abstract · Added March 7, 2014
Several studies with bacteria and in vitro mammalian systems have provided evidence of the roles of two thiol-based conjugation systems, glutathione (GSH) transferase and O(6)-alkylguanine DNA-alkyltransferase (AGT), in the bioactivation of the bis-electrophiles 1,2-dibromoethane and 1,2,3,4-diepoxybutane (DEB), the latter an oxidation product of 1,3-butadiene. The in vivo relevance of these conjugation reactions to biological activity in mammals has not been addressed, particularly with DEB. In this work, we used transgenic Big Blue mice, utilizing the cII gene, to examine the effects of manipulation of conjugation pathways on liver mutations arising from dibromoethane and DEB in vivo. Treatment of the mice with butathionine sulfoxime (BSO) prior to dibromoethane lowered hepatic GSH levels, dibromoethane-GSH DNA adduct levels (N(7)-guanyl), and the cII mutation frequency. Administration of O(6)-benzylguanine (O(6)-BzGua), an inhibitor of AGT, did not change the mutation frequency. Depletion of GSH (BSO) and AGT (O(6)-BzGua) lowered the mutation frequency induced by DEB, and BSO lowered the levels of GSH-DEB N(7)-guanyl and N(6)-adenyl DNA adducts. Our results provide evidence that the GSH conjugation pathway is a major in vivo factor in dibromoethane genotoxicity; both GSH conjugation and AGT conjugation are major factors in the genotoxicity of DEB. The latter findings are considered to be relevant to the carcinogenicity of 1,3-butadiene.
0 Communities
1 Members
0 Resources
20 MeSH Terms
Mutation spectra of S-(2-hydroxy-3,4-epoxybutyl)glutathione: comparison with 1,3-butadiene and its metabolites in the Escherichia coli rpoB gene.
Cho SH, Guengerich FP
(2012) Chem Res Toxicol 25: 1522-30
MeSH Terms: Animals, Butadienes, Cell Survival, Chromatography, High Pressure Liquid, DNA, DNA Adducts, DNA-Directed RNA Polymerases, Epoxy Compounds, Escherichia coli, Escherichia coli Proteins, Glutathione, Glutathione Transferase, Mice, Microsomes, Liver, Mutagenicity Tests, Mutation, Rats, Tandem Mass Spectrometry
Show Abstract · Added March 7, 2014
S-(2-Hydroxy-3,4-epoxybutyl)glutathione (DEB-GSH conjugate) is formed from the reaction of 1,2:3,4-diepoxybutane (DEB) with glutathione (GSH), and the conjugate is considerably more mutagenic than several other butadiene-derived epoxides-including DEB-in Salmonella typhimurium TA1535 [Cho, S.-H., (2010) Chem. Res. Toxicol. 23, 1544-1546]. We previously identified six DNA adducts in the reaction of the DEB-GSH conjugate with nucleosides and calf thymus DNA and two DNA adducts in livers of mice and rats treated with DEB [Cho, S.-H. and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 706-712]. To define the role of GSH conjugation in 1,3-butadiene (BD) metabolism and characterize the mechanism of GSH transferase (GST)-enhanced mutagenicity of DEB, mutation spectra of BD and its metabolites in the absence and presence of GST/GSH and mouse liver microsomes were compared in the rpoB gene of Escherichia coli TRG8. The presence of GST considerably enhanced mutations. The mutation spectra derived from the DEB-GSH conjugate, the DEB/GST/GSH system, and the BD/mouse liver microsomes/GST/GSH system matched each other and were different from those derived from the other systems devoid of GSH. The major adducts in E. coli TRG8 cells treated with the DEB/GST/GSH system, the BD/mouse liver microsomes/GST/GSH system, or the DEB-GSH conjugate were S-[4-(N(7)-guanyl)-2,3-dihydroxybutyl]GSH, S-[4-(N(3)-adenyl)-2,3-dihydroxybutyl]GSH, and S-[4-(N(6)-deoxyadenosinyl)-2,3-dihydroxybutyl]GSH, indicating the presence of the GSH-containing DNA adducts in the systems. These results, along with the strong enhancement of mutagenicity by GST in this system, indicate the relevance of these GSH-containing DNA adducts.
0 Communities
1 Members
0 Resources
18 MeSH Terms
Mutagenicity of a glutathione conjugate of butadiene diepoxide.
Cho SH, Loecken EM, Guengerich FP
(2010) Chem Res Toxicol 23: 1544-6
MeSH Terms: Animals, Butadienes, DNA, Epoxy Compounds, Glutathione, Glutathione Transferase, Mutagenicity Tests, Rats, Salmonella typhimurium
Show Abstract · Added March 7, 2014
The mutagenicity and carcinogenicity of the important commodity chemical 1,3-butadiene are attributed to the epoxide products. We confirmed our previous work showing that expression of rat glutathione (GSH) transferase 5-5 enhances the mutagenicity of butadiene diepoxide in Salmonella typhimurium TA1535. A GSH-butadiene diepoxide conjugate was isolated and fully characterized by mass spectrometry and nuclear magnetic resonance as S-(2-hydroxy-3,4-epoxybutyl)GSH. The conjugate had a t(½) of 2.6 h (pH 7.4, 37 °C) and was considerably more mutagenic than butadiene diepoxide or monoepoxide in S. typhimurium. We propose that the GSH conjugate may be a major species involved in butadiene genotoxicity, not a detoxication product.
0 Communities
1 Members
0 Resources
9 MeSH Terms
MEK and EGFR inhibition demonstrate synergistic activity in EGFR-dependent NSCLC.
Balko JM, Jones BR, Coakley VL, Black EP
(2009) Cancer Biol Ther 8: 522-30
MeSH Terms: Apoptosis, Butadienes, Carcinoma, Non-Small-Cell Lung, Cell Line, Tumor, Cell Survival, Enzyme Activation, ErbB Receptors, Gene Silencing, Humans, Lung Neoplasms, Mitogen-Activated Protein Kinase Kinases, Nitriles, Protein Kinase Inhibitors
Show Abstract · Added March 10, 2014
Epidermal growth factor receptor (EGFR) inhibitors are highly effective in treating non-small cell lung cancers (NSCLC) expressing activated EGFR, particularly those harboring EGFR mutations.  However, most patients who benefit from EGFR inhibitors achieve only partial responses or stable disease, facilitating the emergence of resistance.  Thus, progression-free survival advantages in responding patients are modest.  Combination therapy, preferably using agents with synergistic activity, could both improve responses and reduce acquired resistance rates.   We hypothesized that combining MEK inhibitors with EGFR inhibitors could result in such a benefit.  The MAPK pathway lies downstream of EGFR and transduces both proliferative and survival signals in a variety of cancer types.  Inhibitors of this pathway are currently in clinical trials, but little evidence exists supporting the use of these agents as monotherapy in EGFR-dependent non-small cell lung cancer.   In this study, we find EGFR-dependent NSCLC cell lines are moderately sensitive to loss of ERK1/2 activity, either by small molecule inhibition or by siRNA knockdown.  The consequence of inhibition is dependent upon the trophic content of the culture media, primarily anti-proliferative in serum-rich conditions and pro-apoptotic in serum-poor conditions. However, when ERK inhibition combined with EGFR inhibitors, cytotoxic synergy was observed for all EGFR-dependent cell lines tested in serum-containing media.  Enhanced cytotoxicity is demonstrated in cell lines with and without EGFR mutations, including those harboring the T790M escape mutation.  These findings support future clinical studies that combine EGFR- and MEK1/2-targeted agents to investigate whether improved outcomes can be achieved in clinically screened EGFR-dependent NSCLC.
0 Communities
1 Members
0 Resources
13 MeSH Terms
Probiotics ameliorate the hydrogen peroxide-induced epithelial barrier disruption by a PKC- and MAP kinase-dependent mechanism.
Seth A, Yan F, Polk DB, Rao RK
(2008) Am J Physiol Gastrointest Liver Physiol 294: G1060-9
MeSH Terms: Bacterial Proteins, Butadienes, Caco-2 Cells, Cadherins, Dose-Response Relationship, Drug, Electric Impedance, HT29 Cells, Humans, Hydrogen Peroxide, Indoles, Intestinal Mucosa, Inulin, Lactobacillus rhamnosus, Membrane Proteins, Mitogen-Activated Protein Kinase 1, Mitogen-Activated Protein Kinase 3, Mitogen-Activated Protein Kinases, Nitriles, Occludin, Permeability, Phosphoproteins, Probiotics, Protein Kinase C, Protein Kinase C beta, Protein Kinase C-epsilon, Protein Kinase Inhibitors, Protein Transport, Pyrroles, Tight Junctions, Time Factors, Zonula Occludens-1 Protein, beta Catenin
Show Abstract · Added May 19, 2014
Probiotics promote intestinal epithelial integrity and reduce infection and diarrhea. We evaluated the effect of Lactobacillus rhamnosus GG-produced soluble proteins (p40 and p75) on the hydrogen peroxide-induced disruption of tight junctions and barrier function in Caco-2 cell monolayers. Pretreatment of cell monolayers with p40 or p75 attenuated the hydrogen peroxide-induced decrease in transepithelial resistance and increase in inulin permeability in a time- and dose-dependent manner. p40 and p75 also prevented hydrogen peroxide-induced redistribution of occludin, ZO-1, E-cadherin, and beta-catenin from the intercellular junctions and their dissociation from the detergent-insoluble fractions. Both p40 and p75 induced a rapid increase in the membrane translocation of PKCbetaI and PKCepsilon. The attenuation of hydrogen peroxide-induced inulin permeability and redistribution of tight junction proteins by p40 and p75 was abrogated by Ro-32-0432, a PKC inhibitor. p40 and p75 also rapidly increased the levels of phospho-ERK1/2 in the detergent-insoluble fractions. U0126 (a MAP kinase inhibitor) attenuated the p40- and p75-mediated reduction of hydrogen peroxide-induced tight junction disruption and inulin permeability. These studies demonstrate that probiotic-secretory proteins protect the intestinal epithelial tight junctions and the barrier function from hydrogen peroxide-induced insult by a PKC- and MAP kinase-dependent mechanism.
0 Communities
1 Members
0 Resources
32 MeSH Terms
Plasmin(ogen) promotes renal interstitial fibrosis by promoting epithelial-to-mesenchymal transition: role of plasmin-activated signals.
Zhang G, Kernan KA, Collins SJ, Cai X, López-Guisa JM, Degen JL, Shvil Y, Eddy AA
(2007) J Am Soc Nephrol 18: 846-59
MeSH Terms: Actins, Animals, Butadienes, Cadherins, Cell Movement, Collagen, Disease Models, Animal, Enzyme Inhibitors, Extracellular Signal-Regulated MAP Kinases, Female, Fibrinolysin, Fibrosis, Kidney, Kidney Diseases, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Nitriles, Phosphorylation, Plasminogen Activator Inhibitor 1, Receptor, PAR-1, Signal Transduction, Transforming Growth Factor beta, Ureteral Obstruction
Show Abstract · Added February 3, 2012
Plasminogen (Plg) activator inhibitor-1 (PAI-1) is an important fibrosis-promoting molecule. Whether this effect can be attributed to PAI-1's activity as an inhibitor of plasmin generation is debated. This study was designed to investigate the role of Plg in renal fibrosis using in vivo and in vitro approaches. Plg-deficient (Plg-/-) and wild-type (Plg+/+) C57BL/6 mice were subjected to unilateral ureteral obstruction or sham surgery (n = 8/group; sham, days 3, 7, 14, and 21). Plg deficiency was confirmed by the absence of Plg mRNA, protein, and plasmin activity. After 21 d of unilateral ureteral obstruction, total kidney collagen was significantly reduced by 35% in the Plg-/- mice. Epithelial-to-mesenchymal transition (EMT), as typified by tubular loss of E-cadherin and acquisition of alpha-smooth muscle actin, was also significantly reduced in Plg-/- mice, 76% and 50%, respectively. Attenuation of EMT and fibrosis severity in the Plg-/- mice was associated with significantly lower levels of phosphorylated extracellular signal-regulated kinase (ERK) and active TGF-beta. In vitro, addition of plasmin (20 microg/ml) to cultures of murine tubular epithelial cells initiated ERK phosphorylation within minutes, followed by phenotypic transition to fibroblast-specific protein-1+, alpha-smooth muscle actin+, fibronectin-producing fibroblast-like cells. Both plasmin-induced ERK activation and EMT were significantly blocked in vitro by the protease-activated receptor-1 (PAR-1) silencing RNA; by pepducin, a specific anti-PAR-1 signaling peptide; and by the ERK kinase inhibitor UO126. Plasmin-induced ERK phosphorylation was enhanced in PAR-1-overexpressing tubular cells. These findings support important profibrotic roles for plasmin that include PAR-1-dependent ERK signaling and EMT induction.
0 Communities
1 Members
0 Resources
25 MeSH Terms
Structure of the 1,4-bis(2'-deoxyadenosin-N6-yl)-2R,3R-butanediol cross-link arising from alkylation of the human N-ras codon 61 by butadiene diepoxide.
Merritt WK, Nechev LV, Scholdberg TA, Dean SM, Kiehna SE, Chang JC, Harris TM, Harris CM, Lloyd RS, Stone MP
(2005) Biochemistry 44: 10081-92
MeSH Terms: Alkylating Agents, Base Pairing, Butadienes, Butylene Glycols, Codon, Cross-Linking Reagents, DNA Adducts, Deoxyadenosines, Epoxy Compounds, Genes, ras, Humans, Mutagens, Nuclear Magnetic Resonance, Biomolecular, Nucleic Acid Heteroduplexes, Oligodeoxyribonucleotides, Protons
Show Abstract · Added May 29, 2014
The solution structure of the 1,4-bis(2'-deoxyadenosin-N(6)-yl)-2R,3R-butanediol cross-link arising from N(6)-dA alkylation of nearest-neighbor adenines by butadiene diepoxide (BDO(2)) was determined in the oligodeoxynucleotide 5'-d(CGGACXYGAAG)-3'.5'-d(CTTCTTGTCCG)-3'. This oligodeoxynucleotide contained codon 61 (underlined) of the human N-ras protooncogene. The cross-link was accommodated in the major groove of duplex DNA. At the 5'-side of the cross-link there was a break in Watson-Crick base pairing at base pair X(6).T(17), whereas at the 3'-side of the cross-link at base pair Y(7).T(16), base pairing was intact. Molecular dynamics calculations carried out using a simulated annealing protocol, and restrained by a combination of 338 interproton distance restraints obtained from (1)H NOESY data and 151 torsion angle restraints obtained from (1)H and (31)P COSY data, yielded ensembles of structures with good convergence. Helicoidal analysis indicated an increase in base pair opening at base pair X(6).T(17), accompanied by a shift in the phosphodiester backbone torsion angle beta P5'-O5'-C5'-C4' at nucleotide X(6). The rMD calculations predicted that the DNA helix was not significantly bent by the presence of the four-carbon cross-link. This was corroborated by gel mobility assays of multimers containing nonhydroxylated four-carbon N(6),N(6)-dA cross-links, which did not predict DNA bending. The rMD calculations suggested the presence of hydrogen bonding between the hydroxyl group located on the beta-carbon of the four-carbon cross-link and T(17) O(4), which perhaps stabilized the base pair opening at X(6).T(17) and protected the T(17) imino proton from solvent exchange. The opening of base pair X(6).T(17) altered base stacking patterns at the cross-link site and induced slight unwinding of the DNA duplex. The structural data are interpreted in terms of biochemical data suggesting that this cross-link is bypassed by a variety of DNA polymerases, yet is significantly mutagenic [Kanuri, M., Nechev, L. V., Tamura, P. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2002) Chem. Res. Toxicol. 15, 1572-1580].
0 Communities
1 Members
0 Resources
16 MeSH Terms
Dual roles of glycosyl torsion angle conformation and stereochemical configuration in butadiene oxide-derived N1 beta-hydroxyalkyl deoxyinosine adducts: a structural perspective.
Merritt WK, Kowalczyk A, Scholdberg TA, Dean SM, Harris TM, Harris CM, Lloyd RS, Stone MP
(2005) Chem Res Toxicol 18: 1098-107
MeSH Terms: Alkylation, Butadienes, DNA, Glycosylation, Hydrogen, Inosine, Magnetic Resonance Spectroscopy, Molecular Conformation, Oxygen, Protons, Stereoisomerism
Show Abstract · Added May 29, 2014
The solution structure of the N1-[1-hydroxy-3-buten-2(R)-yl]-2'-deoxyinosine adduct arising from the alkylation of adenine N1 by butadiene epoxide (BDO), followed by deamination to deoxyinosine, was determined in the oligodeoxynucleotide 5'-d(CGGACXAGAAG)-3'.5'-d(CTTCTTGTCCG)-3'. This oligodeoxynucleotide contained the BDO adduct at the second position of codon 61 of the human N-ras protooncogene (underlined) and was named the ras61 R-N1-BDO-(61,2) adduct. 1H NMR revealed a weak C5 H1' to X6 H8 nuclear Overhauser effects (NOE), followed by an intense X6 H8 to X6 H1' NOE. Simultaneously, the X6 H8 to X6 H3' NOE was weak. The resonances arising from the T16 and T17 imino protons were not observed. 1H NOEs between the butadiene moiety and the DNA positioned the adduct in the major groove. Structural refinement based upon a total of 394 NOE-derived distance restraints and 151 torsion angle restraints yielded a structure in which the modified deoxyinosine was in the syn conformation about the glycosyl bond, with a glycosyl bond angle of 83 degrees , and T17, the complementary nucleotide, was stacked into the helix but not hydrogen bonded with the adducted inosine. The refined structure provides a plausible hypothesis as to why these N1 deoxyinosine adducts strongly code for the incorporation of dCTP during trans lesion DNA replication, irrespective of stereochemistry, both in Escherichia coli [Rodriguez, D. A., Kowalczyk, A., Ward, J. B. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2001) Environ. Mol. Mutagen. 38, 292-296] and in mammalian cells [Kanuri, M., Nechev, L. N., Tamura, P. J., Harris, C. M., Harris, T. M., and Lloyd, R. S. (2002) Chem. Res. Toxicol. 15, 1572-1580]. Rotation of the N1 deoxyinosine adduct into the syn conformation may facilitate incorporation of dCTP via Hoogsteen type templating with deoxyinosine, generating A to G mutations. However, conformational differences between the R- and the S-N1-BDO-(61,2) adducts, involving the positioning of the butenyl moiety in the major groove of DNA, suggest that adduct stereochemistry plays a secondary role in modulating the biological response to these adducts.
0 Communities
1 Members
0 Resources
11 MeSH Terms