Toxic metal interactions with DNA: a FTIR study, 1995

genotoicity. Today, understanding the mechanism of metal-DNA interactions is becoming increasingly important since a number of potentially hazardous trace metals are now consistenly found in the atmosphere, soil, and water supplies. Mercury (II) has shown a definite interaction with DNA at the molecular level in our studies of binding at physiological pH. Spectral changes in the region of nucleobase show strong evidence of a Hg(II)-nucleobase interaction with a marked preference for thymine sites. These results confirm that interaction between Hg(II) and DNA occurs primarily through the nucleobase as opposed to the phosphate backbone. Ni(II) has shown no indication of metal-phosphate interaction in our FTIR studies as a function of pH. In aqueous solution Ni(II) shows limited interaction with DNA. As a consequence, further studies of the effect of Ni(II) on DNA need to be carried out. When DNA is exposed simultaneously to mercury and nickel, a strong Hg(II)-nucleobase interaction is still observed. There is no obvious enhancement for the affinity of DNA by metal 1 (Hg(II)) because of the addition of metal 2 (Ni(II)), nor could the existence of a competitive relationship be proven