[en] Interaction of native calf thymus DNA (ctDNA) with the actinocin derivatives containing protonated diethylamino groups, dimethylamino groups and unsubstituted amino groups and having different length of the alkyl chain have been studied by the method of viscometry. An anomalous hydrodynamic behavior of solutions of DNA with very low amount of ligands prepared under conditions of semidilute solution was revealed. We assumed that such an anomalous behavior of solutions of DNA complexes with actinocin derivatives associated with the formation of intermolecular crosslinks while the preparation of the complex was in terms of overlapping of macromolecular coils in solution. Comparative study of the hydrodynamic behavior of the DNA complexes with various actinocin structures lead us to the conclusion of the formation of crosslinks by the compounds containing protonated diethylamino groups

[en] Interaction of native calf thymus DNA (ctDNA) with phenacylimidazo[5,1- a]isoquinoline derivatives was studied by the methods of spectrophotometry, viscometry, isothermal titration calorimetry (ITC) and dynamic birefringence. It was found that both of investigated compounds form complexes with the DNA molecule, the structure of compounds affects the mode of binding these ligands to DNA. The primary binding mode can not be described by the classical models of groove binding or intercalation. It has been suggested that the primary mode of binding is 'partial intercalation'. (paper)

[en] The interaction of DNA molecule with new synthetic compounds, piperazine derivatives of benzo[4,5]imidazo[1,2-a]phthalazine, was investigated by the spectral, hydrodynamic and optical methods. The thermodynamic parameters of the interaction and the stoichiometry of the complexes were determined by spectrophotometric titration. A mode of binding and structure of the complexes were determined by analyzing the changes in the intrinsic viscosity and the optical anisotropy of the macromolecule upon complexation. It is shown that an increase in the intrinsic viscosity and the optical anisotropy with a small content of the ligand in the complex is caused by the increase in the thermodynamic rigidity of macromolecules upon the formation of the complex. Increase of the contour length of the macromolecule in the complex does not occur, that indicates nonintercalative mode of binding the piperazine derivatives of benzoimidazophthalazine with DNA. (paper)