Mitoxantrone interaction with $\mathrm{poly(G)}$

In the present work the thermodynamic studies of mitoxantrone complexformation with four-stranded $\mathrm{poly(G)}$ have been carried out. The binding thermodynamic parameters, the binding constant $K$ and the number of nucleotides corresponding to one binding site $n$, were determined. It was shown that mitoxantrone is bound stronger with four-stranded $\mathrm{poly(G)}$, then it is bound with double-stranded helix. It was also shown that due to difficulties of the intercalation of mitoxantrone molecules into four-stranded structure is bound mainly by external binding mode with $[\mathrm{poly(G)}]_4$ and at the interaction saturation mitoxantrone bound to much more guanines ($n\cong10$) per one molecule.