Zinc binding to lambda phage DNA studied by voltammetric techniques

Abstract

A interação do zinco com o DNA do fago λ foi investigada utilizando a voltametria de pulso diferencial e a voltametria cíclica. Os métodos baseiam-se no monitoramento direto da corrente de redução e oxidação do zinco na ausência e na presença do DNA viral. Curvas de titulação do Zn 2+ com o DNA do fago λ foram obtidas nos intervalos de concentração 3,57 x 10 -12 a 3,92 x 10 -11 mol L -1 e 6,97 x 10 -12 a 5,56 x 10 -11 mol L -1 . Estes dados foram utilizados para o cálculo da constante de dissociação do complexo e da estequiometria. O mecanismo da reação foi estudado utilizando a voltametria cíclica. Curvas do tipo I (corrente de oxidação do zinco) versus v 1/2 (raiz quadrada da velocidade de varredura) mostraram que o processo oxidação-redução do zinco deixa de ser difusional na presença do DNA do fago λ.Binding of zinc to lambda phage DNA was investigated by differential pulse voltammetry and cyclic voltammetry. These methods rely on the direct monitoring of reduction and oxidation current of zinc in the absence and presence of this virion DNA. Titration graphs of Zn 2+ with DNA were obtained in the concentration ranges from 3.57 x 10 -12 to 3.92 x 10 -11 mol L -1 and 6.97 x 10 -12 to 5.56 x 10 -11 mol L -1 . These data were used to calculate the dissociation constant of the complex and the stoichiometry. The mechanism of this reaction was studied by cyclic voltammetry through curves I (oxidation current of Zn 2+ ) versus v 1/2 (square root of scan rate). These curves showed that the oxidation-reduction process of Zn 2+ was not controlled by diffusion in the presence of lambda phage DNA.

Virucidal Action Mechanism of Alcohol and Divalent Cations Against Human Adenovirus

“…Free zinc ions (Zn 2+ ) have been shown to be able to bind to DNA and change its secondary structure mainly through interactions with DNA phosphate sugar backbone as well as guanine and cytosine (Aich et al, 1999). A high ratio of Zn 2+ to DNA has also been shown to destabilize the DNA double helix decreasing its melting temperatures (Souza et al, 2000;Labiuk et al, 2003). In addition, the viral genome can impact on capsid mechanics (Labiuk et al, 2001;Ivanovska et al, 2007).…”

The binding of zinc (II) to a double-stranded oligodeoxyribonucleotide. A voltammetric study

“…However, only electrochemical methods proved to be suitable to determine the quantitative parameters of Zn 2+ -DNA complexes by studying the voltammetry of zinc in the absence and in the presence of DNA and noting shifts in standard potential caused by the interaction. Recently, the interaction of zinc ions with Lambda Phage DNA was studied by voltammetric techniques [39]. In this study, the stoichiometry and dissociation constant of the complex were successfully determined by the direct monitoring of the reduction and oxidation currents of zinc in the absence and in the presence of this virion DNA.…”