MODE OF DNA-BINDING OF BIS-BENZIMIDAZOLES AND RELATED STRUCTURES STUDIED BY ELECTRIC LINEAR DICHROISM

The binding mode of a series of bis-benzimidazole analogues of Hoechst 33258 to a variety of DNAs and polynucleotides has been investigated by electric linear dichroism. Two groups of compounds were examined: ( i) benzoxazole and pyridoimidazole derivatives and (ii) pyridoimidazol e analogs substituted with an N-alkoxyalkyl group either directed towa rds the minor groove or directed away from the minor groove. The ELD d ata indicate that the mode of binding of these drugs varies significan tly with the sequence of the target DNA sequence. The DNA binding prop erties' of these drugs are related to their topoisomerase inhibitory p roperties.