DIFFERENTIAL UV-SPECTROSCOPIC STUDIES OF TRANSITION-METAL ION-INTERACTION WITH DNA AND ITS MONOMERS

Data are presented for the base atoms coordinating Cu2+, Ni2+, Cd2+ io ns in DNA and its monomers, which were derived from the analysis of th e shapes of UVD spectra taken on metal complexes. The corresponding bi nding constants are found. The Ni2+ and Cd2+ ions are noted for a very weak, as compared to Cu2+ ions, interaction with cytosine of nucleoti des. As a result, Cd2+ and Ni2+ ions can cause only internal protonati on of N3C in the GC pairs of DNA on their interaction with N7G. In the case of Cu2+ ions this interaction leads to the quasi-Hoogsteen trans ition of the GC pairs. (C) 1997 Elsevier Science B.V.