Biopolymers and cell. 1989. Volume 5. № 6. 25 - 32

S. V. Kornilova, A. G. Shkorbatov, Yu. P. Blagoi

EFFECT OF ALKALIEARTH AND TRANSITION METAL IONS ON HYDRODYNAMIC AND MACROMOLECULAR PARAMETERS OF DNA

Summary

    DNA intrinsic viscosity ft]] and the excluded volume parameter e iare stated to depend on the concentrations and the binding degrees of Mg2+, Mn2+, Ga2+, Cu2+ ions with different Nad contents (2 •!lO-4+,10-' M). The substantial changes of the [r\] value and the parameter e in the presence of small contents of bivalent metal ions are shown to be due to the ion binding to the phosphate 'groups and nitrogen bases of DNA. Bivalent ion (Me2+)-DNA binding results in the suppression of long-range effects in a macromolecule with concentrations by some orders of magnitude lower than those in the case of monovalent ions. The effect of transition metal ions (Mn2+, Cu2+) on the value and the excluded volume parameter is greater than that of the alkali-earth (Ca2+, Mg2+) ones due to their binding not only to DNA phosphate groups but aJso to the nitrogen bases even with small concentrations (5-10-6 M). The intrinsic viscosity and the excluded volume parameter are shown to depend universally on the binding degree of bivalent ions.