The Effect of Deuterium on Induction of the ada-Regulon with Alkylating Compounds in the Cells of Escherichia coli

This study has shown for the first time that deuterium oxide (D2O) enhances expression of the E. coli ada-regulon induced by alkylating compounds, N-nitroso-N-methylurea (NMU) and methyl methanesulfonate (MMS). To compare the induction of ada-regulon in deuterated and in non-deuterated (control) cultures of E. coli, a biosensor based on the E. coli strain K12 MG1655 (pAlkA–lux) luminescing as a result of activating the alkA gene promoter in response to DNA alkylation was used. Depending on the D2O concentration from 5 to 10% in the pre-deuterium medium, these alkylating compounds at a concentration of 0.005 M induced expression of the alkA gene from 1.3 to 5 times higher as compared to induction in nondeuterated culture. It is suggested that deuterium can be one of the main factors in stabilizing the bond between the promoter and the alkylated Ada protein, leading to increased transcription of the ada-regulon.