<p>These sequences represent the CopA copper resistance protein family. CopA is related to laccase (benzenediol:oxygen oxidoreductase) and L-ascorbate oxidase, both copper-containing enzymes. Most members have a typical TAT (twin-arginine translocation) signal sequence with an Arg-Arg pair. Twin-arginine translocation is observed for a large number of periplasmic proteins that cross the inner membrane with metal-containing cofactors already bound. The combination of copper-binding sites and TAT translocation motif suggests a mechanism of resistance by packaging and export. </p> Copper-resistance protein CopA