DNA/HSA interaction and nuclease activity of an iron(III) amphiphilic sulfonated corrole.

The DNA binding of amphiphilic iron(III) 2,17-bis(sulfonato)-5,10,15-tris(pentafluorophenyl)corrole complex (Fe-SC) was studied using spectroscopic methods and viscosity measurements. Its nuclease-like activity was examined by using pBR322 DNA as a target. The interaction of Fe-SC with human serum albumin (HSA) in vitro was also examined using multispectroscopic techniques. Experimental results revealed that Fe-SC binds to ct-DNA via an outside binding mode with a binding constant of 1.25 × 10(4) M(-1). This iron corrole also displays good activity during oxidative DNA cleavage by hydrogen peroxide or tert-butyl hydroperoxide oxidants, and high-valent (oxo)iron(V,VI) corrole intermediates may play an important role in DNA cleavage. Fe-SC exhibits much stronger binding affinity to site II than site I of HSA, indicating a selective binding tendency to HSA site II. The HSA conformational change induced by Fe-SC was confirmed by UV/Vis and CD spectroscopy.

DNA Binding, Photonuclease Activity and Human Serum Albumin Interaction of a Water-Soluble Freebase Carboxyl Corrole.

The DNA binding property of 5,10,15-Tris(4-carboxyphenyl) corrole (TCPC) was studied by UV-Visible, fluorescence and circular dichroism (CD) spectroscopic methods. TCPC can bind to ct-DNA via an outside binding mode with the binding constant of Kb = 1.05 × 105 M(-1). TCPC also displayed good photonuclease activity, which involves singlet oxygen species (¹O2). The binding constant between TCPC and human serum albumin (HSA) is KA = 2.24 × 105 M(-1) with a simulated binding distance of 2.06 nm. The fluorescence quenching of HSA by TCPC followed a static quenching process. Site marker competitive displacement experiments indicated that warfarin site I is the main binding site. The secondary structure of HSA was changed upon interaction with TCPC, which was confirmed by UV-Visible and CD spectroscopy.