Interaction of Norfloxacin with Super-Coiled DNA

2003 Bulletin of the Korean Chemical Society (Print)  
Norfloxacin, that inhibits the action of topoisomerase II, binds to wide variety of DNA. The binding mode of this drug to double-and super-coiled DNA (ds-and scDNA) is compared in this study by various spectroscopic methods, including absorption, fluorescence, and circular dichroism(CD) spectroscopy. Hypochromism in the absorption band, negative and positive induced CD bands (respectively in 240-260 nm and 270-300 nm region) are apparent for the norfloxacin that bound to both the dsDNA and
more » ... . A decrease in fluorescence is also noticed in the presence of both DNAs. Since the spectroscopic characteristics are the same for both complexes, it is imperative that the binding mode of the norfloxacin is similar in ds-and scDNA. In the presence of Mg 2+ , which is a cofactor in the topoisomerase II action, the fluorescence intensity of the scDNA-norfloxacin complex increased and the resulting fluorescence intensity and shape was identical to that in the absence of scDNA. Therefore, the addition of an excess amount of Mg 2+ may result in the extrusion of norfloxacin from scDNA.
doi:10.5012/bkcs.2003.24.5.579 fatcat:ywy3qdmsinba7jiflkt57ph3ly