Oxanine DNA glycosylase activity from Mammalian alkyladenine glycosylase
| Autor: | Weiguo Cao, Liang Dong, Thomas M. Hitchcock, Lisiane B. Meira, Ellen E. Connor, Michael D. Wyatt, Leona D. Samson |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Guanine
Time Factors Base pair Swine Deamination Oligonucleotides DNA Single-Stranded Thymus Gland Biology Biochemistry Xanthine DNA Glycosylases chemistry.chemical_compound Cytosine Mice polycyclic compounds Animals Humans Molecular Biology Hypoxanthine Chromatography High Pressure Liquid DNA Polymerase beta Mice Knockout Nucleotides Nucleic Acid Hybridization Cell Biology DNA Purine Nucleosides biochemical phenomena metabolism and nutrition Molecular biology Thymine chemistry DNA glycosylase Mutagenesis Site-Directed Spleen Protein Binding |
| Zdroj: | The Journal of biological chemistry. 279(37) |
| ISSN: | 0021-9258 |
| Popis: | Oxanine (Oxa) is a deaminated base lesion derived from guanine in which the N(1)-nitrogen is substituted by oxygen. This work reports the mutagenicity of oxanine as well as oxanine DNA glycosylase (ODG) activities in mammalian systems. Using human DNA polymerase beta, deoxyoxanosine triphosphate is only incorporated opposite cytosine (Cyt). When an oxanine base is in a DNA template, Cyt is efficiently incorporated opposite the template oxanine; however, adenine and thymine are also incorporated opposite Oxa with an efficiency approximately 80% of a Cyt/Oxa (C/O) base pair. Guanine is incorporated opposite Oxa with the least efficiency, 16% compared with cytosine. ODG activity was detected in several mammalian cell extracts. Among the known human DNA glycosylases tested, human alkyladenine glycosylase (AAG) shows ODG activity, whereas hOGG1, hNEIL1, or hNEIL2 did not. ODG activity was detected in spleen cell extracts of wild type age-matched mice, but little activity was observed in that of Aag knock-out mice, confirming that the ODG activity is intrinsic to AAG. Human AAG can excise Oxa from all four Oxa-containing double-stranded base pairs, Cyt/Oxa, Thy/Oxa, Ade/Oxa, and Gua/Oxa, with no preference to base pairing. Surprisingly, AAG can remove Oxa from single-stranded Oxa-containing DNA as well. Indeed, AAG can also remove 1,N(6)-ethenoadenine from single-stranded DNA. This study extends the deaminated base glycosylase activities of AAG to oxanine; thus, AAG is a mammalian enzyme that can act on all three purine deamination bases, hypoxanthine, xanthine, and oxanine. |
| Databáze: | OpenAIRE |
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