DNA cleavage by a metal chelating tricationic porphyrin

The demonstrated chemotherapeutic effects of porphyrins have stimulated recent investigations into the nature of porphyrin-cell interactions. That meso-tetra (4-N-methylpyridyl)porphine (TMPyP) intercalates the base pairs of DNA selectively at G-C rich regions has been well-established. super(1)H and super(31)P NMR experiments with oligonucleotides have indicated that the preferred sequence for intercalation of TMPyP is CpG. The broad spectrum reactivity of related iron hemes has been utilized in the design of functional bleomycin models and heme-oligonucleotides adducts which are capable of cleaving complementary single-stranded DNA.