The DNA binding site specificity and antiproliferative property of ternary Pt(ii) and Zn(ii) complexes of phenanthroline and N,N'-ethylenediaminediacet ic acid

The binding site specificity of the ternary complexes, [M(ii)(phen)(edda)] (M(ii) = Pt super(2+) and Zn super(2+); phen = 1,10-phenanthroline; edda = N,N'-ethylenediaminediacet ic acid), for the self-complementary oligonucleotides (ODNs), ds(C sub(1)G sub(2)C sub(3)G sub(4)A sub(5)A sub(6)T sub(7)T sub(8) C sub(9)G sub(10)C sub(11)G sub(12)) sub(2) (ODN1) and ds(C sub(1)G sub(2)C sub(3)G sub(4)T sub(5)A sub(6)T sub(7)A sub(8) C sub(9)G sub(10)C sub(11)G sub(12)) sub(2) (ODN2), was studied by NMR measurements. The results indicated that [Pt(ii)(phen)(edda)] was partially intercalated between C sub(3)/G sub(10) and G sub(4)/C sub(9) base pairs of ODN1 and ODN2 in the major grooves, whereas [Zn(ii)(phen)(edda)] was bound specifically to the TATA region of ODN2 in the minor groove and to the terminal G sub(2)/C sub(11) base pair of ODN1 in the major groove. The preference for the TATA sequence over the AATT sequence in the binding of [Zn(phen)(edda)] was attributed to the wider minor groove width of the TATA sequence. The bindings of the complexes to ct-DNA were also studied by UV, CD, and fluorescence spectroscopy. Additionally, the antiproliferative property of [Pt(ii)(phen)(edda)] towards MCF7 breast cancer cells and normal MCF10-A cells was compared with that of [Zn(ii)(phen)(edda)].