title: Effect of metal ions on transcription of the ada gene which encodes O6-methylguanine-DNA methyltransferase of Escherichia coli.
abstract: The effect of metal ions on transcription of the ada gene of Escherichia coli which is promoted by Ada protein in the presence of methylated deoxyribonucleic acid (DNA) was examined in a reconstituted system. Their effect on the O6-methylguanine-DNA methyltransferase (MGTase) activity of Ada protein was also examined. Ag+, Cd2+, Cu2+ and Hg2+ severely inhibited transcription of the ada gene at a dose which inhibited neither transcription of the lacUV5 gene nor MGTase activity. Zn2+ inhibited both transcription and MGTase activity in the same dose range. Al3+ and Fe3+ inhibited transcription of both ada and lacUV5 genes without affecting the MGTase activity of Ada protein. Inhibitory mechanisms are discussed.
authors.affiliation: Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Sekiguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Kawazoe
mesh_terms: D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D008670:Metals / Q000494:pharmacology*; D008780:Methyltransferases / Q000235:genetics*; D019853:O(6)-Methylguanine-DNA Methyltransferase; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D008670:Metals; D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase