Gold(III)-DNA interaction in aqueous solution

Abstract

Gold(III) complexes resemble cisplatin and other similar platinum(II) complexes in structure and electron properties. Because of this similarity, the coordination compounds formed by gold(III) can find application in medicine. They are considered to bind with DNA, disrupting its normal replication. However, there are a few available papers devoted to the study of the interaction between tetrachloroaurate(III), which is used often for the synthesis of other gold(III) complexes, and DNA. The stability constants of gold(III) and DNA are also useful for studying the reactions between gold(III) complexes and DNA, as the dissociation of the metal complex is possible. Therefore, this paper describes the interactions between [AuCl4]- and its hydrolyzed species and DNA in pure water and aqueous 0.1 M NaCl solution. Binding mode and binding constants are determined from the results of UV–Vis and circular dichroism titration, while the kinetic fluorescent measurements are used to study the ethidium bromide replacement. Atomic force microscopy is also used to show the influence of gold(III) species on DNA. The calculated equilibrium constants are used to calculate the speciation diagram for the solution containing chlorohydroxyaurate(III) species, hydrazone derived from pyridoxal 5′-phosphate, and DNA at different pH values.