Metal complexes of porphyrin–anthraquinone hybrids: DNA binding and photocleavage specificities

Abstract

A cationic porphyrin–anthraquinone hybrid and its Zn(II), Cu(II), Co(III), and Mn(III) complexes were synthesized and their interactions with duplex DNA were studied using a combination of absorption, fluorescence titration, circular dichroism spectroscopy, thermal DNA denaturation, viscosity measurements, gel electrophoresis, and gas chromatography. Metal coordination induces intermolecular steric hindrance and thus the metal hybrids have smaller DNA binding affinities than the free base hybrid; the steric hindrance could relax the intermolecular aggregation and increase ¹O₂ generation of the metal hybrids. The DNA photocleavage abilities of these hybrids were investigated.

Keywords:

• Porphyrin–anthraquinone hybrid
• DNA-binding
• Steric hindrance
• DNA photocleavage

Acknowledgments

This work was financially supported by Guangdong Pharmaceutical University and the Medical Research Foundation of Guangdong (B2010158).