Enzyme Repair of Excoyclic Adducts

Summary

Principal Investigator: Bo Hang
Abstract: The primary focus of this renewal proposal is on how repair enzymes process specific exocyclic DNA adducts, which are formed by diverse environmental mutagens/carcinogens including vinyl compounds, glycidyl ethers, chlorohydroxyfuranones, benzene and therapeutic nitrosoureas such as BCNU or formed by endogenous processes. Unrepaired adducts can block replication or cause mutation since many of these exocyclic adducts are miscoding lesions. The exocyclic adducts to be studied are structurally related but with differing features. Our central hypothesis is that such ring structural features, formed by different carcinogens, will determine specific enzymatic recognition and the type of repair. On this basis, we hope to identify and characterize new repair activities or novel repair enzymes. The proposed approaches from biochemistry and structural studies attempt to define specific structural features or rules that are essential for enzymatic recognition or repair efficiency. In addition, protein-protein interactions in glycosylase excision of exocyclic adducts will be investigated. By using in vitro biochemical approaches and specific oligonucleotides containing a single site-directed adduct, we wish to carry out the following specific aims: (1) To identify DNA glycosylases/endonucleases acting on newly synthesized exocyclic adducts; (2) To examine the initial recognition by mismatch repair (MMR) pathway of the available exocyclic adducts as these lesions form similar structures to mismatches; (3) To explore the potential pathway for p-benzoquinone adduct repair using an in vitro substitution methodology; (4) To study how and to what extent the DNA glycosylases excising exocyclic adducts interact with other cellular proteins such as 5'AP endonucleases, XPG protein and the MMR binding proteins; and (5) Structural studies, such as molecular modeling of damaged DNA/glycosylase complexes, will be performed to aid in understanding how repair enzymes interact with such adducted DNA.
Funding Period: 1996-09-05 - 2008-03-31
more information: NIH RePORT

Top Publications

  1. ncbi The p-benzoquinone DNA adducts derived from benzene are highly mutagenic
    Zhongwen Xie
    Graduate Center for Toxicology, University of Kentucky, Lexington, 40536, USA
    DNA Repair (Amst) 4:1399-409. 2005
  2. ncbi Alkylpurine-DNA-N-glycosylase excision of 7-(hydroxymethyl)-1,N6-ethenoadenine, a glycidaldehyde-derived DNA adduct
    Ping Wang
    Department of Molecular Biology, Life Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
    DNA Repair (Amst) 5:23-31. 2006
  3. ncbi Metal inhibition of human N-methylpurine-DNA glycosylase activity in base excision repair
    Ping Wang
    Department of Molecular Biology, Life Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
    Toxicol Lett 166:237-47. 2006
  4. ncbi Substrate specificity of human thymine-DNA glycosylase on exocyclic cytosine adducts
    Bo Hang
    Department of Genome Stability, Life Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
    Chem Biol Interact 165:230-8. 2007
  5. ncbi Synthesis of the fully protected phosphoramidite of the benzene-DNA adduct, N2-(4-Hydroxyphenyl)-2'-deoxyguanosine and incorporation of the later into DNA oligomers
    Ahmed Chenna
    Monogram Biosciences Inc, South San Francisco, California, USA
    Nucleosides Nucleotides Nucleic Acids 27:979-91. 2008
  6. ncbi Benzene-derived N2-(4-hydroxyphenyl)-deoxyguanosine adduct: UvrABC incision and its conformation in DNA
    Ben Rodriguez
    Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA 94132, USA
    Toxicol Lett 193:26-32. 2010

Scientific Experts

  • Bo Hang
  • Anton B Guliaev
  • Ping Wang
  • Ahmed Chenna
  • Ben Rodriguez
  • Zhongwen Xie
  • Yanu Yang
  • Ramesh C Gupta
  • Francis Johnson
  • Radha R Bonala
  • Rhoderick H Elder
  • Huiyun Shen
  • Zhigang Wang
  • Yangbin Zhang
  • B Singer

Detail Information

Publications6

  1. ncbi The p-benzoquinone DNA adducts derived from benzene are highly mutagenic
    Zhongwen Xie
    Graduate Center for Toxicology, University of Kentucky, Lexington, 40536, USA
    DNA Repair (Amst) 4:1399-409. 2005
    ..When the lesion becomes incompatible in accommodating a base opposite the lesion in DNA, translesion synthesis occurs by a less efficient lesion loop-out mechanism, resulting in avoiding copying the damaged base and leading to deletion...
  2. ncbi Alkylpurine-DNA-N-glycosylase excision of 7-(hydroxymethyl)-1,N6-ethenoadenine, a glycidaldehyde-derived DNA adduct
    Ping Wang
    Department of Molecular Biology, Life Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
    DNA Repair (Amst) 5:23-31. 2006
    ..These novel substrate specificities could have both biological and structural implications...
  3. ncbi Metal inhibition of human N-methylpurine-DNA glycosylase activity in base excision repair
    Ping Wang
    Department of Molecular Biology, Life Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
    Toxicol Lett 166:237-47. 2006
    ..These data suggest that inhibition of MPG activity may contribute to metal genotoxicity and depressed repair of alkylation damage by metals in vivo...
  4. ncbi Substrate specificity of human thymine-DNA glycosylase on exocyclic cytosine adducts
    Bo Hang
    Department of Genome Stability, Life Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
    Chem Biol Interact 165:230-8. 2007
    ..These findings expand the TDG substrate range and aid in understanding the structural requirements for TDG substrate specificity...
  5. ncbi Synthesis of the fully protected phosphoramidite of the benzene-DNA adduct, N2-(4-Hydroxyphenyl)-2'-deoxyguanosine and incorporation of the later into DNA oligomers
    Ahmed Chenna
    Monogram Biosciences Inc, South San Francisco, California, USA
    Nucleosides Nucleotides Nucleic Acids 27:979-91. 2008
    ..The oligomers were purified by reverse-phase HPLC. Enzymatic hydrolysis and HPLC analysis confirmed the presence of this adduct in the oligomers...
  6. ncbi Benzene-derived N2-(4-hydroxyphenyl)-deoxyguanosine adduct: UvrABC incision and its conformation in DNA
    Ben Rodriguez
    Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA 94132, USA
    Toxicol Lett 193:26-32. 2010
    ..In addition, N(2)-4-HOPh-dG has a tendency to form more stable stacking interactions than a normal G in B-type DNA. These conformational properties may be critical in differential recognition of this adduct by specific repair enzymes...