Deoxyribonucleic acid (DNA) lies in the core of cancer and is an attractive target for chemotherapy. Interaction of drugs with DNA is widely used to screen for their biological activity. Ruthenium and rhodium octahedral complexes have shown non-covalent and covalent modification of of DNA.1,2 In particular, Ru-Rh bimetallic architectures, with the general structure [(TL)2Ru(BL)Rh(TL)Cl2]3+ (TL=terminal ligand, BL=bridging ligand), have shown oxygen-independent cleavage and binding via visible light activation.3 Nevertheless, non-covalent interactions of these supramolecular complexes with DNA remain unexplored. Binding affinity of a Ru-Rh bimetallic to DNA was studied under different ionic strengths and in the presence of competitive binders, in order to understand the impact of non-covalent interactions on covalent modification of this biomolecule. Electronic absorption and emission spectroscopy indicate contribution of different non-covalent binding modes. Moreover, non-covalent interactions stablished between the complex and DNA during photolysis impact the extend of binding and cleavage, as evidenced through gel electrophoresis. Acknowledgement is made to VT ICTAS 119552 and the National Science Foundation 478898 for their generous funding. 1. Pyle, A. M.; Rehmann, J. P.; Meshoyrer, R.; Kumar, C. V.; Turro, N. J.; Barton, J. K., Mixed-ligand complexes of ruthenium(II): factors governing binding to DNA. Journal of the American Chemical Society 1989, 111 (8), 3051-3058. 2. Erkkila, K. E.; Odom, D. T.; Barton, J. K., Recognition and Reaction of Metallointercalators with DNA. Chemical Reviews 1999, 99 (9), 2777-2796. 3. Wang, J.; Zigler, D. F.; Hurst, N.; Othee, H.; Winkel, B. S. J.; Brewer, K. J., A new, bioactive structural motif: Visible light induced DNA photobinding and oxygen independent photocleavage by RuII, RhIII bimetallics. Journal of Inorganic Biochemistry 2012, 116 (0), 135-139.

Non-covalent interactions of a Ru-Rh supramolecular complex with DNA and their effect on covalent modification of the biomolecule

249th National Meeting (2015)

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