Metalloporphyrins associated with oxygen atom donors are biomimetic models of heme, enzymes such as cytochrome P450 and peroxidases. Some cationic porphyrins recognize DNA (double-stranded DNA and G-quadruplex DNA) with high specificity and selectivity. In aqueous buffer manganese porphyrins are activated by oxone. Two examples of oxidation reactions mediated by cationic manganese porphyrins in complex with DNA will be presented. Oxidation can be directed toward DNA and results in highly selective DNA damage (i) or may be directed toward oxidation of small molecules in a heme DNAzyme context (ii). DNA damage mediated by manganese porphyrins allowed a better understanding of the reactivity of high-valent metal-oxo species. The reaction pathway (electron abstraction versus oxygen atom transfer) depends on the protonation state of the water molecule present as axial ligand trans to the metal-oxo. The analysis of the reaction products of a manganese porphyrin in complex with G-quadruplex DNA gives insights on the mode of interaction of the porphyrin with DNA.

- Interaction of cationic manganese porphyrin with G-quadruplex nucleic acids probed by differential labeling of the two faces of the porphyrin V. Pradines, G. Pratviel Angew. Chem. Int. Ed. 52, 2185-2188 (2013)

- Protonation state of trans axial water molecule switches the reactivity of high-valent manganese-oxo porphyrin J. Trzcionka, J. Irvoas, G. Pratviel New J. Chem. 37, 3581-3590 (2013)

- Porphyrins in complex with DNA: modes of interaction and oxidation reactions G. Pratviel Coord. Chem. Rev. http://dx.doi.org/10.1016/j.ccr.2015.07.003