Differential inactivation of mammalian and Escherichia coli O6-alkylguanine-DNA alkyltransferases by O6-benzylguanine.
AffiliationCRC Department of Carcinogenesis, Paterson Institute for Cancer Research, Christie Hospital (NHS) Trust, Manchester, U.K.
MetadataShow full item record
AbstractThe action of O6-benzylguanine (O6-BzlG) on recombinant mammalian and Escherichia coli O6-alkylguanine-DNA alkyltransferases (ATase; EC 188.8.131.52; methylated-DNA-protein-cysteine methyltransferase) was compared by preincubation of these proteins with the base, followed by measurement of residual ATase activity using [3H]methylated substrate DNA. All of the mammalian proteins examined were inactivated by O6-BzlG (Chinese hamster: I40, 0.04 microM; human and rat: I40, 0.06 microM); however, the murine ATase was substantially more resistant requiring 4-5 fold higher concentrations of O6-BzlG to achieve the same levels of inactivation (I40, 0.28 microM). A similar differential inactivation was seen with human and murine ATases when extracts of 3T6 (murine) cells and Raji (human) cells were compared. Of the two E. coli ATase proteins, only the ogt-encoded protein was inactivated, but approximately 400 times more O6-BzlG was required to achieve a level of inactivation similar to that seen with the human protein (I40, 24.8 microM). When O6-BzlG was present in an oligonucleotide, the differential effect on the murine, human and ogt-encoded ATases was not seen and only the ada-encoded ATase remained refractory under the conditions used.
CitationDifferential inactivation of mammalian and Escherichia coli O6-alkylguanine-DNA alkyltransferases by O6-benzylguanine. 1994, 298 ( Pt 1):231-5 Biochem. J.
JournalThe Biochemical Journal
- Comparison of the inactivation of mammalian and bacterial O6-alkylguanine-DNA alkyltransferases by O6-benzylguanine and O6-methylguanine.
- Authors: Dolan ME, Pegg AE, Dumenco LL, Moschel RC, Gerson SL
- Issue date: 1991 Dec
- A single amino acid change in human O6-alkylguanine-DNA alkyltransferase decreasing sensitivity to inactivation by O6-benzylguanine.
- Authors: Crone TM, Pegg AE
- Issue date: 1993 Oct 15
- Expression in mammalian cells of the Escherichia coli O6 alkylguanine-DNA-alkyltransferase gene ogt reduces the toxicity of alkylnitrosoureas.
- Authors: Harris LC, Margison GP
- Issue date: 1993 Jun
- Mechanism of inactivation of human O6-alkylguanine-DNA alkyltransferase by O6-benzylguanine.
- Authors: Pegg AE, Boosalis M, Samson L, Moschel RC, Byers TL, Swenn K, Dolan ME
- Issue date: 1993 Nov 16
- Repair of O6-benzylguanine by the Escherichia coli Ada and Ogt and the human O6-alkylguanine-DNA alkyltransferases.
- Authors: Goodtzova K, Kanugula S, Edara S, Pauly GT, Moschel RC, Pegg AE
- Issue date: 1997 Mar 28