Higher-Order G-Quadruplex Structures and Porphyrin Ligands: An Ambiguous Relationship

The obtainment of tailored DNA nanostructures provided with structural and functional features useful for nanotechnological and medical applications represents one of the hottest topics in recent literature. In particular, the unusual DNA secondary structures known as G-quadruplexes, which form when guanine-rich DNA and RNA strands are annealed in the presence of physiological cations such as Na+ and K+, proved effective for the obtainment of DNA assemblies displaying in vitro anticancer1, antiviral2 or anticoagulant3 activity, mostly due to their ability to recognise and bind with high specificity and affinity their target proteins. It has been demonstrated that both the kinetics of formation and the stability of G-quadruplexes are affected not only by the nature and concentration of coordinating cations, but also by the presence of G-quadruplex ligands, including those having porphyrin-based core.4 In this communication, I will report the results of our recent studies on the effect of the addition of porphyrin-based derivatives on the stability and overall topology of G-quadruplex superstructures