Chaperone that serves for the intracellular sequestration and transport of Cu(+). Delivers Cu(+) to the copper-transporting ATPase CopA. Functions in E.coli to transfer Cu(+) to CopA missing its first metal-binding domain (PubMed:25899340). Monomer in the absence of copper. Homodimer in the presence of copper ions. Forms a heterodimer (electrostatic interactions) with CopA during the transfer of Cu(+). By Cu(2+). The copZA operon is activated by CueR and indirectly repressed by YfmP. Cu(+) ion is always at least three-coordinated. Physiological thiol may be needed to complete the Cu(+) coordination sphere in order to prevent homodimer (dead-end products) formation between 2 CopZ.