4-Picoline-2,2′:6′,2″-terpyridine-platinum(II) is shown in a ligation assay to unwind and so intercalate into DNA. Circular dichroism is used to determine an equilibrium binding constant of approximately 2 × 107 M-1 for the most stable binding mode of 4-picoline-2,2′:6′,2″-terpyridine-platinum(II) to poly[d(A-T)2] with a site size of about 4 base pairs, and about 1 × 106 M-1 for a second binding mode with a site size of about 2 base pairs. Fluorescence spectroscopy provides further evidence for the strong equilibrium binding constant of 4-picoline-2,2′:6′,2″-terpyridine-platinum(II) in that it displaces ethidium bromide bound to DNA. The double positive charge on 4-picoline-2,2′:6′,2″-terpyridine-platinum(II), together with the intercalative binding mode is probably responsible for the large binding constant.
|Number of pages||6|
|Publication status||Published - 12 Feb 1996|
- Circular dichroism
- DNA ligation
- Fluorescence spectroscopy