Expanding the DNA Damaging Potential of Artificial Metallo-Nucleases with Click Chemistry

The preparation of new metallodrugs targeting DNA is of key therapeutic interest. Recently, the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) "click chemistry" reaction has emerged as a promising approach for designing new artificial metallo-nucleases (AMNs) with DNA-damaging properties. By functionalising a central organic azide with three alkyne donors, Tri-Click (TC) ligands capable of chelating three copper ions through the donor group and triazole linker can be generated. However, the versatility of this approach along with the influence of specific donors on metal binding, DNA recognition, and cellular DNA damage in an anticancer context remains poorly understood. Here, we prepared a library of Tri-Click ligands incorporating systematic cyclic and acyclic N-, O-, and S-donors and evaluated their AMN activities. Screening experiments pinpoint planar N-donor ligands as high value agents. Among these, the copper complex of Tri-Click-Pyridine ( Cu ₃ -TC-Py ) displays significant potential. We characterised its activity using single-molecule imaging, microscale thermophoresis, FRET-based binding assays, molecular dynamics, and intracellular DNA interaction studies in human and functional bacterial cells. We report the emergence of Cu ₃ -TC-Py as a lead AMN with high reactivity for DNA damage applications central to anticancer therapy.