The effect of Se salts on DNA structure.

There is considerable interest in the role of selenium in cancer prevention. Various organic and inorganic Se compounds are considered to be antioxidants. In the present study, the binding modes, the binding constants and the stability of Se-DNA complexes have been determined by Fourier transform infrared (FTIR) and UV-Visible spectroscopic methods. Spectroscopic evidence showed that Na(2)SeO(4) and Na(2)SeO(3) bind to the minor and major grooves of DNA and the backbone phosphate (PO(2)) with overall binding constants of K(Na(2)SeO(4)-DNA)=5.20×10(4) M(-1) and K(Na(2)SeO(3)-DNA)=1.87×10(3) M(-1). DNA aggregations occurred at high selenium concentrations. No biopolymer conformational changes were observed upon Na(2)SeO(3) and Na(2)SeO(4) interactions, while DNA remained in the B-family structure.