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dc.contributor.authorSaparbaev, Murat K
dc.contributor.authorLangouët, Sophie
dc.contributor.authorPrivezentzev, Cyril V
dc.contributor.authorGuengerich, F Peter
dc.contributor.authorCai, Hongliang
dc.contributor.authorElder, Rhoderick H
dc.contributor.authorLaval, Jacques
dc.date.accessioned2009-10-16T11:12:29Z
dc.date.available2009-10-16T11:12:29Z
dc.date.issued2002-07-26
dc.identifier.citation1,N(2)-ethenoguanine, a mutagenic DNA adduct, is a primary substrate of Escherichia coli mismatch-specific uracil-DNA glycosylase and human alkylpurine-DNA-N-glycosylase. 2002, 277 (30):26987-93 J. Biol. Chem.en
dc.identifier.issn0021-9258
dc.identifier.pmid12016206
dc.identifier.doi10.1074/jbc.M111100200
dc.identifier.urihttp://hdl.handle.net/10541/84320
dc.description.abstractThe promutagenic and genotoxic exocyclic DNA adduct 1,N(2)-ethenoguanine (1,N(2)-epsilonG) is a major product formed in DNA exposed to lipid peroxidation-derived aldehydes in vitro. Here, we report that two structurally unrelated proteins, the Escherichia coli mismatch-specific uracil-DNA glycosylase (MUG) and the human alkylpurine-DNA-N-glycosylase (ANPG), can release 1,N(2)-epsilonG from defined oligonucleotides containing a single modified base. A comparison of the kinetic constants of the reaction indicates that the MUG protein removes the 1,N(2)-epsilonG lesion more efficiently (k(cat)/K(m) = 0.95 x 10(-3) min(-1) nm(-1)) than the ANPG protein (k(cat)/K(m) = 0.1 x 10(-3) min(-1) nm(-1)). Additionally, while the nonconserved, N-terminal 73 amino acids of the ANPG protein are not required for activity on 1,N(6)-ethenoadenine, hypoxanthine, or N-methylpurines, we show that they are essential for 1,N(2)-epsilonG-DNA glycosylase activity. Both the MUG and ANPG proteins preferentially excise 1,N(2)-epsilonG when it is opposite dC; however, unlike MUG, ANPG is unable to excise 1,N(2)-epsilonG when it is opposite dG. Using cell-free extracts from genetically modified E. coli and murine embryonic fibroblasts lacking MUG and mANPG activity, respectively, we show that the incision of the 1,N(2)-epsilonG-containing duplex oligonucleotide has an absolute requirement for MUG or ANPG. Taken together these observations suggest a possible role for these proteins in counteracting the genotoxic effects of 1,N(2)-epsilonG residues in vivo.
dc.language.isoenen
dc.subject.meshAnimals
dc.subject.meshCell-Free System
dc.subject.meshDNA Adducts
dc.subject.meshDNA Glycosylases
dc.subject.meshDNA Repair
dc.subject.meshEscherichia coli
dc.subject.meshGuanine
dc.subject.meshHumans
dc.subject.meshKinetics
dc.subject.meshMice
dc.subject.meshModels, Chemical
dc.subject.meshN-Glycosyl Hydrolases
dc.subject.meshOligonucleotides
dc.subject.meshProtein Binding
dc.subject.meshSubstrate Specificity
dc.subject.meshUracil-DNA Glycosidase
dc.title1,N(2)-ethenoguanine, a mutagenic DNA adduct, is a primary substrate of Escherichia coli mismatch-specific uracil-DNA glycosylase and human alkylpurine-DNA-N-glycosylase.en
dc.typeArticleen
dc.contributor.departmentCancer Research United Kingdom Carcinogenesis Group, Paterson Institute for Cancer Research, Christie Hospital, Manchester, UK. M20 4BXen
dc.identifier.journalThe Journal of Biological Chemistryen
html.description.abstractThe promutagenic and genotoxic exocyclic DNA adduct 1,N(2)-ethenoguanine (1,N(2)-epsilonG) is a major product formed in DNA exposed to lipid peroxidation-derived aldehydes in vitro. Here, we report that two structurally unrelated proteins, the Escherichia coli mismatch-specific uracil-DNA glycosylase (MUG) and the human alkylpurine-DNA-N-glycosylase (ANPG), can release 1,N(2)-epsilonG from defined oligonucleotides containing a single modified base. A comparison of the kinetic constants of the reaction indicates that the MUG protein removes the 1,N(2)-epsilonG lesion more efficiently (k(cat)/K(m) = 0.95 x 10(-3) min(-1) nm(-1)) than the ANPG protein (k(cat)/K(m) = 0.1 x 10(-3) min(-1) nm(-1)). Additionally, while the nonconserved, N-terminal 73 amino acids of the ANPG protein are not required for activity on 1,N(6)-ethenoadenine, hypoxanthine, or N-methylpurines, we show that they are essential for 1,N(2)-epsilonG-DNA glycosylase activity. Both the MUG and ANPG proteins preferentially excise 1,N(2)-epsilonG when it is opposite dC; however, unlike MUG, ANPG is unable to excise 1,N(2)-epsilonG when it is opposite dG. Using cell-free extracts from genetically modified E. coli and murine embryonic fibroblasts lacking MUG and mANPG activity, respectively, we show that the incision of the 1,N(2)-epsilonG-containing duplex oligonucleotide has an absolute requirement for MUG or ANPG. Taken together these observations suggest a possible role for these proteins in counteracting the genotoxic effects of 1,N(2)-epsilonG residues in vivo.


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