Superoxide Dismutase Copper Chaperone

Copper (Cu) is required for aerobic life and yet, paradoxically, is highly toxic. This apparent contradiction has been rationalized by assuming that Cu, like other redox-active metals, is sequestered in nonreactive forms as it is transported into cells and moves through cellular compartments. Culotta et al. (1997) determined that one such Cu chaperone protein, Lys7, specifically delivers Cu to copper/zinc superoxide dismutase (Sod1) in S. cerevisiae. By searching EST databases, they identified cDNAs encoding the human Lys7 homolog, which they named CCS (copper chaperone for SOD1). The predicted 274-amino acid human protein is 28% identical to Lys7. CCS complemented a yeast Lys7 mutation, demonstrating that CCS is a functional homolog of Lys7.