Abstract

Porphyrins and biomolecules: A long-lasting friendship

Author(s): Alessandro Dâ??Urso

Porphyrins are quite versatile molecules successfully used in many fields: from nanotechnology to biomedicine. These hetero-aromatic macrocycles present remarkable electronic properties which bring to attractive spectroscopic features. The non-covalent interactions of water-soluble achiral porphyrins with chiral templates have been exploited to detect and/or amplify the matrix handedness. The interaction of achiral cationic porphyrins with DNA has been extensively studied and utilized as reporters of different sequences of DNA bases. We have reported that a cationic Zn(II)porphyrin (ZnT4) and an anionic Ni(II)porphyrin (NiTPPS) were able to spectroscopically detect the left-handed Z-DNA under highly competitive conditions. Moreover, thanks to its peculiar properties, NiTPPS/Spermine/Z-DNA complex shows to be quite a versatile system. In fact, as response to pH perturbations, it is able to reversibly release the chiral information stored in the porphyrin and/or in the DNA helix portion of the supramolecular complex. Finally, using pH and temperature as input and porphyrin ICD as output, our system behaves as a reversible AND logic gate. To improve the efficiency of our probe we have designed porphyrin spermine derivative able to induce, detect and stabilize the Z form of DNA. Even we have exploited the stabilizing ability of spermine porphyrin, with G-quadruplex structures, obtaining some interesting results. Recently we investigated the potency of porphyrins as inhibitor and modulator of proteasome, which is the protein involved in many biological processes. The inhibition of proteasome is promising strategy to cure of tumors.