Interaction of a ruthenium(II)–chalcone complex with double stranded DNA: Spectroscopic, molecular docking and nuclease properties

The interaction of a well characterized new complex 1cis,fac-[RuCl(dmso-S)3(L)] LH = 1-(2-hydroxyphenyl)-3-(4-chlorophenyl) propenone with Calf-thymus DNA (CT-DNA) is monitored using UV–vis titration (Kb = 3.8 × 107) and ethidium bromide displacement studies (Ksv = 3.2). The molecular docking of the complex with DNA sequence d(ACCGACGTCGGT)2 reveals that complex is stabilized by additional electrostatic and hydrogen bonding interaction with DNA besides probable displacement of a labile DMSO by the N7 of guanine. The coordination of guanine is further supported by the isolation and characterization of its adduct with the complex 1.gua (gua = guanine). The nuclease property of complex 1 in the absence and presence of different activators and trappers demonstrates that complex efficiently cleaves supercoiled pBR322 plasmid DNA and binds through major groove of the DNA.

Graphical abstractA newly synthesized complex cis,fac-[RuCl(dmso-S)3(L)] (LH = 1-(2-hydroxyphenyl)-3-(4-chlorophenyl) propenone) binds with DNA and cleaves a supercoiled pBR322 plasmid DNA via oxidative pathway.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A Ru(II) complex [Ru(L)(dmso)3Cl] containing chalcone is synthesized and characterized using spectral and X-ray crystallographic data. ► In vitro DNA binding studies of the complex is carried out using absorption and emission spectral studies. ► The docked structure of complex with DNA sequence d(ACCGACGTCGGT)2 showed its interaction mainly through phenyl ring inside the DNA major groove. ► DNA is cleaved by the complex from 20 to 100 μM. ► At lower concentration 40 μM, the cleavage of DNA is activated by well known activators and cleavage follows the oxidative pathway.