Intramolecular DNA Coiling Mediated by a Metallo-Supramolecular Cylinder

In the groove! A tetracationic supramolecular cylinder, [Fe2L3]4+ (L=C25H20N4), with a triple-helical architecture is just the right size to fit into the major groove of DNA (see picture) and too big to fit into the minor groove. NMR spectroscopic data confirm that the cylinder binds in the major groove. Linear dichroism shows that very low loadings of [Fe2L3]4+ have a dramatic bending effect on the DNA and atomic force microscopy images show that this is an intramolecular effect resulting in coils of DNA.