INTERACTION OF DNA WITH COORDINATION-COMPOUNDS OF BIVALENT PLATINUM .3. PLATINUM COMPOUNDS WITH 2 PYRIMIDINE LIGANDS

The interaction of DNA with coordination compounds of bivalent platinu m containing 5-substituted uracil ligands (R = H, Br, NO2) was studied . For all title complexes, the mode of interaction with DNA in solutio n is virtually unaffected by the nature of the substituent. Ionic stre ngth has only a slight effect on complex formation. The platinum compo unds alter the optical anisotropy of DNA but have no influence on its circular dichroism and hydrodynamic parameters. It is assumed that the platinum complexes bind to the macromolecule so that the pyrimidine l igands are on the periphery of the double helix. It is possible in thi s case that the NH3 groups form hydrogen bonds with the phosphate oxyg ens.