Nucleic acid-binding comparative studies and cytotoxic properties of a Ru(II) complex

Abstract

The comparative studies on the interaction of a ruthenium(II) complex [Ru(IP)2DPBPD(NH2)2]2+ (1) {IP = imidazole[4,5-f] [1,10] phenanthroline, DPBPD(NH2)2 = 2,4,5,6-tetraaminopyrimidine-[3,2-a:2′,3′-c]-phenazine} with CT-DNA (calf thymus DNA) and yeast tRNA have been investigated by different spectrophotometric methods and viscosity measurements. The antitumor activities of complex 1 have been evaluated by MTT {MTT = (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide} method. On the basis of the spectroscopic results, the binding mode of complex 1 to CT-DNA and yeast tRNA are intercalation, and RNA binding of complex 1 is stronger than DNA binding. Furthermore, complex 1 is a better candidate for an enantioselective binder to yeast tRNA than to CT-DNA. The results can be explained by the different structure and configuration between CT-DNA and yeast tRNA reasonably, suggesting that the configuration and structure of nucleic acids have significant effects on the binding behaviors of metal complexes. On the other hand, the complex demonstrates different antitumor activity against selected tumor cell lines in vitro.