Abstact

Cellular systems for handling transition metal ions have been identified, but little is known about the structure and function of the specific trafficking proteins. The 1.8 A resolution structure of the yeast copper chaperone for superoxide dismutase (yCCS) reveals a protein composed of two domains. The N-terminal domain is very similar to the metallochaperone protein Atx1 and is likely to play a role in copper delivery and/or uptake. The second domain resembles the physiological target of yCCS, superoxide dismutase I (SOD1), in overall fold, but lacks all of the structural elements involved in catalysis. In the crystal, two SOD1-like domains interact to form a dimer. The subunit interface is remarkably similar to that in SOD1, suggesting a structural basis for target recognition by this metallochaperone.