Polypyridyl-Based Copper Phenanthrene Complexes: A New Type of Stabilized Artificial Chemical Nuclease |
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Authors: | Nicoló Zuin Fantoni Dr. Zara Molphy Dr. Creina Slator Georgia Menounou Gianluca Toniolo Dr. George Mitrikas Prof. Vickie McKee Dr. Chryssostomos Chatgilialoglu Prof. Andrew Kellett |
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Affiliation: | 1. School of Chemical Sciences and National Institute for Cellular, Biotechnology, Dublin City University, 9 Glasnevin, Dublin, Ireland;2. ISOF-CNR Area della Ricerca di Bologna, Via P. Gobetti 101, 40129 Bologna, Italy;3. Institute of Nanoscience and Nanotechnology, N.C.S.R. Demokritos, Agia Paraskevi Attikis, P.O. Box 60037, 15341 Athens, Greece |
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Abstract: | The building of robust and versatile inorganic scaffolds with artificial metallo-nuclease (AMN) activity is an important goal for bioinorganic, biotechnology, and metallodrug research fields. Here, a new type of AMN combining a tris-(2-pyridylmethyl)amine (TPMA) scaffold with the copper(II) N,N′-phenanthrene chemical nuclease core is reported. In designing these complexes, the stabilization and flexibility of TPMA together with the prominent chemical nuclease activity of copper 1,10-phenanthroline (Phen) were targeted. A second aspect was the opportunity to introduce designer phenazine DNA intercalators (e.g., dipyridophenazine; DPPZ) for improved DNA recognition. Five compounds of formula [Cu(TPMA)(N,N′)]2+ (where N,N′ is 2,2-bipyridine (Bipy), Phen, 1,10-phenanthroline-5,6-dione (PD), dipyridoquinoxaline (DPQ), or dipyridophenazine (DPPZ)) were developed and characterized by X-ray crystallography. Solution stabilities were studied by continuous-wave EPR (cw-EPR), hyperfine sublevel correlation (HYSCORE), and Davies electron–nuclear double resonance (ENDOR) spectroscopies, which demonstrated preferred geometries in which phenanthrene ligands were coordinated to the copper(II) TPMA core. Complexes with Phen, DPQ, and DPPZ ligands possessed enhanced DNA binding activity, with DPQ and DPPZ compounds showing excellent intercalative effects. These complexes are effective AMNs and analysis with spin-trapping scavengers of reactive oxygen species and DNA repair enzymes with glycosylase/endonuclease activity demonstrated a distinctive DNA oxidation activity compared to classical Sigman- and Fenton-type reagents. |
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Keywords: | chemical nuclease copper DNA damage DNA repair phenazine |
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