Spectral studies of the binding of lucigenin, a bisacridinium derivative, with double-helix DNA.

The non-covalent binding of the cationic reagent lucigenin to DNA has been investigated by spectroscopic methods. Results from absorption, circular dichroism, and fluorescence studies revealed that lucigenin could intercalate into the helix of DNA. Polarization and melting studies provided further evidence of the intercalation binding of lucigenin with DNA. The binding constant was obtained by varying the DNA concentration while keeping the concentration of lucigenin constant. It was of the order of 10(4) mol(-1) L in DNA base pairs. The experiment also showed that electrostatic interaction played a significant role in the intercalation of lucigenin with DNA. It is suggested that lucigenin can be intercalated into the interior of the DNA double helix because it is initially attracted by the anionic DNA. This research offers a new intercalation functional group for DNA-targeted drug design.