[Interaction of DNA with actinocyl-bis-thiazole].

The DNA complexes with actinocyl-bis-bithiazole have been investigated by spectrophotometry, viscometry and flow birefringence. It was estimated, that at low degrees of binding (r < or = 0.07) this compound binds to DNA by bisintercalation via bithiazole groups located in positions 1 and 9 of the phenoxazone chromophore. The phenoxazone moiety plays in this case the role of a link connecting two intercalating fragments. As r increases, external groove binding becomes the second type of complex formation.