Electrochemical behavior of anthraquinone- and nitrophenyl-labeled deoxynucleoside triphosphates: a contribution to development of multipotential redox labeling of DNA

Electrochemical properties of base-modified cytosine or 7-deazaadenine nucleoside triphosphates (dNTPs) bearing electrochemically active anthraquinone or 3-nitrophenyl moieties were studied using cyclic voltammetry with the hanging mercury drop electrode. The anthraquinone moiety in the dNTPs gives well-pronounced reversible quinone/hydroquinone redox signals around −0.40 V (against Ag|AgCl|3M KCl reference electrode), while the nitro group in 3-nitrophenyl exhibits irreversible reduction to hydroxylamine around −0.45 V that can be reversibly oxidized to corresponding nitroso compound close to 0.0 V. Both anthraquinone and hydroxylamine redox groups can be selectively switched off by further electrochemical transformation, depending on negative potential applied and composition of the background electrolyte. Results of this study suggest that both nucleobase and the conjugate label moiety influence remarkably the adsorbability and/or intermolecular interactions taking part at the electrode surface. The potential analytical utilization of these phenomena is discussed. Graphical abstract