Interactions Of Water-Soluble Porphyrins With Z-Poly(Dg-Dc)

The water soluble porphyrin tetrakis(4-N-methylpyridyl)porphine (H₂TMpyP) and its copper(ll) derivative (CuTMpyP) convert Z-poly(dG-dC) to the B-form. For H₂TMpyP, the fraction Z character (fr-Z) is given by fr-Z=1.0–21 r₀ and for CuTMpyP, fr-Z=.94–12 rₒ where rₒ s [Porphyrin]ₒ/[DNA]ₒ. Neither the manganese(lll) derivative of this porphyrin (MnTMpyP) nor tetrakis(2-N-methylpyridyl)porphine (H₂TMpyP-2) is nearly as effective at causing the conversion. The former two porphyrins have been shown to intercalate into B-poly(dG-dC) whereas the latter two porphyrins do not