Is capable of binding multiple equivalents of a variety of divalent and trivalent metals, including Cu(2+) and Fe(3+) but also Mn(2+), Ni(2+), Mg(2+) and Zn(2+). Is able to bind up to six Cu(2+) atoms. It is proposed to be a metal scavenging protein that has a role in cellular copper management in N.europaea. Monomer. By copper. There are two separate and distinct copper binding sites, a high-affinity site and a lower affinity site, which display negative cooperativity.