Two sequential phosphates 3' adjacent to the 8-oxoguanosine are crucial for lesion excision by E. coli Fpg protein and human 8-oxoguanine-DNA glycosylase.
Escherichia coli formamidopyrimidine-DNA glycosylase (Fpg) and human 8-oxoguanine-DNA glycosylase (hOGG1) are base excision repair enzymes involved in the 8-oxoguanine (oxoG) repair pathway. Specific contacts between these enzymes and DNA phosphate groups play a significant role in DNA-protein interactions. To reveal the phosphates crucial for lesion excision by Fpg and hOGG1, modified DNA duplexes containing pyrophosphate and OEt-substituted pyrophosphate internucleotide (SPI) groups near the oxoG were tested as substrate analogues for both proteins. We have shown that Fpg and hOGG1 recognize and specifically bind the DNA duplexes tested. We have found that both enzymes were not able to excise the oxoG residue from DNA containing modified phosphates immediately 3' to the 8-oxoguanosine (oxodG) and one nucleotide 3' away from it. In contrast, they efficiently incised DNA duplexes bearing the same phosphate modifications 5' to the oxodG and two nucleotides 3' away from the lesion. The effect of these phosphate modifications on the substrate properties of oxoG-containing DNA duplexes is discussed. Non-cleavable oxoG-containing DNA duplexes bearing pyrophosphate or SPI groups immediately 3' to the oxodG or one nucleotide 3' away from it are specific inhibitors for both 8-oxoguanine-DNA glycosylases and can be used for structural studies of complexes comprising a wild-type enzymes bound to oxoG-containing DNA.
Laboratory of Nucleic Acids Chemistry, Department of Chemistry, Moscow State University, Moscow 119899, Russia.
Maria V
MV
Rogacheva
Murat K
MK
Saparbaev
Ivan M
IM
Afanasov
Svetlana A
SA
Kuznetsova
D001483:Base Sequence; D045647:DNA Glycosylases / Q000737:chemistry / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D043382:DNA-Formamidopyrimidine Glycosylase / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D006151:Guanosine / Q000031:analogs & derivatives* / Q000032:analysis; D006801:Humans; D007700:Kinetics; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism; D010710:Phosphates / Q000032:analysis*; D013379:Substrate Specificity
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D009838:Oligodeoxyribonucleotides; D010710:Phosphates; D006151:Guanosine; C046215:8-hydroxyguanosine; D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human; D043382:DNA-Formamidopyrimidine Glycosylase; C468610:DNA-formamidopyrimidine glycosylase, E coli