Studies on the Interaction of Poly (I:C) With Cu^(2+)

Metal ions play important roles in the biological functions of nucleic adds. It is of importance to the life sciences to investigate the reaction of nucleic acids with metal ions. In the note the interaction of double-stranded helical structure nucleic acid, polyinosinic acid: polycytidylic acid （poly （I:C）） with Cu2+ is studied by means of absorption spectra, circular dichroism, fluorescent spectra, melting and cooling curves, acid titration curves and ethidium bromide fluorescent probe. The results show that Cu2+ breaks the hydrogen-bonded structure of poly （I: C）, and the poly （I: C） untwisting induced by Cu2+ is un-reversible and the apparent binding constant of poly （I: C） with Cu2+ is 1.23×104