Binding of metalloporphyrins to G-quadruplex DNA: The role of the central metal

Two series of metalated cationic porphyrins were evaluated for their capacity to bind G-quadruplex DNA as well as for their specificity with respect to duplex DNA as a function of the metal ion inserted in the core of the porphyrin. Various metal ions (Ni2+, Co3+, Mn3+) afforded variation of the charge and axial coordination in the center of the porphyrin. The binding affinity of the metalated porphyrins toward DNA (G-quadruplex DNA and duplex DNA) was evaluated by Surface Plasmon Resonance and the influence of the metal was compared with that reported for TMPyP4. The second generation porphyrins were better G-quadruplex ligands than TMPyP4 porphyrins and, on the contrary to the TMPyP4 series, the metal had no influence on the K-D values. (C) 2016 Elsevier B.V. All rights reserved.