STUDIES OF INTERACTION OF DNA WITH CU2-SPECTROSCOPY METHODS( B Y IR AND RAMAN)

DNA with Cu2+ ions in solution and films is studied by IR and Raman sp ectroscopy at different relative humidities (R.H. = 51+98%). DNA compl exed with Cu2+ ions is shown to transit to the double-helix conformati on, passing A-form, the water content per nucleotide (n) being essenti ally larger: 12 for Cu2+/P=0.4 (n=8 for DNA without ions). Cu2+ decrea se the biopolymer hydration at R.H. 50-76% interactions with Cu2+ are stated to depend on the hydration degree of macromolecules. The analys is of the absorption band shifts of Raman spectra evidences the change s in the base torsion angle around the glycoside bond to the values ch aracteristic of the syn-conformation and the interaction both with pho sphates and nitrogen bases.