Interaction Mode Between Methylene Blue-Pr(III) Complex and Herring-Sperm DNA

By spectroscopic method, the binding ratios between methylene blue-Pr(III) and DNA in physiological pH environment (pH=7.40) were determined as nPr:nMB(III)=1:3 and nPr(III)(MB)3:nDNA=8:1. The binding constants at different temperatures [image omitted]=7.14x105L center dot mol-1 and [image omitted]=2.43x105L center dot mol-1 were obtained by double reciprocal method. Thermodynamic function computation demonstrates that [image omitted] is the primary driving power of the interaction between Pr(III)(MB)3 and herring-sperm DNA. According to the analysis, we have evidenced that the interaction mode between Pr(III)(MB)3 complex and herring-sperm DNA is partial intercalation binding