Copperbinding

Copper binding refers to the interaction of copper ions with donor atoms in ligands, including small molecules, proteins, and surfaces. In aqueous environments copper mainly adopts Cu2+ or Cu+ oxidation states and binds through nitrogen, sulfur, and oxygen donors. Coordination geometry varies with oxidation state: Cu2+ commonly forms square-planar or distorted octahedral arrangements, while Cu+ is often linear or tetrahedral.

In biology, copper binding is central to metalloproteins. Enzymes such as ceruloplasmin, CuZn-superoxide dismutase, cytochrome c oxidase, and dopamine β-hydroxylase coordinate copper to enable redox chemistry and catalysis. Copper chaperones, including Atox1, CCS, and COX17, deliver copper to apoenzymes and help maintain cellular copper homeostasis. Binding sites typically involve histidine, cysteine, and methionine ligands, sometimes supplemented by water or other residues.

Characterization and study employ UV-Vis spectroscopy, electron paramagnetic resonance for Cu2+ centers, X-ray crystallography, EXAFS, and isothermal titration calorimetry to determine geometry, affinity, and thermodynamics of binding.

Outside biology, copper-binding interactions influence environmental chemistry by modulating copper mobility and bioavailability through complexation with organic matter and mineral surfaces. In medicine, disorders such as Wilson disease and Menkes disease illustrate the physiological importance of copper binding and homeostasis. In materials and catalysis, designed ligands and polymers exploit copper binding for binding, sensing, or remediation applications.