Alkyl and vinyl halides are of interest because of their high volumes of production, extensive human exposure, and known genotoxicity and carcinogenicity. Continuing studies are directed toward bifunctional electrophiles in this group (including oxidation products) and the related compound butadiene diepoxide, an oxidation product of another commodity chemical (1,3-butadiene). The proposed studies are focused on thiol- dependent activation mechanisms of 1,2-dibromoethane (ethylene dibromide) and butadiene diepoxide, particularly by glutathione (GSH) transferases (GSTs) and the DNA repair protein O6-alkylguanine DNA- alkyltransferase (AGT). The first Specific Aim involves the characterization of mechanisms of mutation of DNA-AGT crosslinks derived from 1,2-dibromoethane and butadiene diepoxide. Further characterization of crosslinks other than the N7-guanyl ones will be done, and a major hypothesis is that peptides derived from AGT are the mutagenic adducts. The second Specific Aim involves the GSH conjugate of butadiene diepoxide and the hypothesis that this is a prominent electrophilic species involved in DNA alkylation and genotoxicity of butadiene diepoxide (as opposed to a detoxication product). An approach is also proposed to evaluate the AGT and GST pathways for these chemicals in rodents in vivo. The third Specific Aim utilizes a new chemical approach to the synthesis of DNA adducts with unstable glycosidic bonds, including several derived from alkyl and vinyl halides, especially N7-(2-oxoethyl)-guanine, S-[N7-(2-guanylethyl)]glutathione, and N2,3-etheno(5)guanine. Our hypothesis is that these adducts are miscoding. The miscoding potentials of these and other unstable adducts will be evaluated with several microbial and human DNA polymerases, and comparisons will be made. Collectively these studies should provide new mechanistic insight into the toxicity and carcinogenicity of these adducts and important information that may alter paradigms in risk assessment.
We propose a research plan that should produce valuable information related to 1,2-dibromo- and 1,2- dichloroethane, butadiene, and other bis-electrophiles or chemicals that can produce bis-electrophiles, which have practical significance in human health considerations. The work with peptides linked to DNA has basic mechanistic importance and fills a scientific need. The new approaches we propose to study involve labile DNA adducts that should allow us to address several long-standing questions about mutagenesis.
|Sedgeman, Carl A; Su, Yan; Guengerich, F Peter (2017) Formation of S-[2-(N6-Deoxyadenosinyl)ethyl]glutathione in DNA and Replication Past the Adduct by Translesion DNA Polymerases. Chem Res Toxicol 30:1188-1196|
|Su, Yan; Egli, Martin; Guengerich, F Peter (2017) Human DNA polymerase ? accommodates RNA for strand extension. J Biol Chem 292:18044-18051|
|Su, Yan; Egli, Martin; Guengerich, F Peter (2016) Mechanism of Ribonucleotide Incorporation by Human DNA Polymerase ?. J Biol Chem 291:3747-56|
|Xue, Qizhen; Zhong, Mengyu; Liu, Binyan et al. (2016) Kinetic analysis of bypass of 7,8-dihydro-8-oxo-2'-deoxyguanosine by the catalytic core of yeast DNA polymerase ?. Biochimie 121:161-9|
|Yeom, Mina; Kim, In-Hyeok; Kim, Jae-Kwon et al. (2016) Effects of Twelve Germline Missense Variations on DNA Lesion and G-Quadruplex Bypass Activities of Human DNA Polymerase REV1. Chem Res Toxicol 29:367-79|
|Su, Yan; Peter Guengerich, F (2016) Pre-Steady-State Kinetic Analysis of Single-Nucleotide Incorporation by DNA Polymerases. Curr Protoc Nucleic Acid Chem 65:7.23.1-7.23.10|
|Patra, Amitraj; Zhang, Qianqian; Guengerich, F Peter et al. (2016) Mechanisms of Insertion of dCTP and dTTP Opposite the DNA Lesion O6-Methyl-2'-deoxyguanosine by Human DNA Polymerase ?. J Biol Chem 291:24304-24313|
|Wickramaratne, Susith; Ji, Shaofei; Mukherjee, Shivam et al. (2016) Bypass of DNA-Protein Cross-links Conjugated to the 7-Deazaguanine Position of DNA by Translesion Synthesis Polymerases. J Biol Chem 291:23589-23603|
|Kim, Jae-Kwon; Yeom, Mina; Hong, Jin-Kyung et al. (2016) Six Germline Genetic Variations Impair the Translesion Synthesis Activity of Human DNA Polymerase ?. Chem Res Toxicol 29:1741-1754|
|O'Flaherty, D K; Patra, A; Su, Y et al. (2016) Lesion Orientation of O(4)-Alkylthymidine Influences Replication by Human DNA Polymerase ?. Chem Sci 7:4896-4904|
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