A Copper(I) Protein Possibly Involved in the Assembly of CuACenter of Bacterial Cytochrome c Oxidase

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 102; no. 11; pp. 3994 - 3999
• Main Authors: Banci, Lucia, Bertini, Ivano, Ciofi-Baffoni, Simone, Katsari, Efthalia, Katsaros, Nikolaos, Kubicek, Karel, Mangani, Stefano, Petsko, Gregory A.
• Format: Journal Article
• Language: English
• Published: National Academy of Sciences 15.03.2005
• Subjects: Amino acids; Atoms; Bacteria; Biological Sciences; Copper; Cytochromes; Eukaryotic cells; Ions; Ligands; Oxidases; Proteins
• ISSN: 0027-8424

Sco1 and Cox17 are accessory proteins required for the correct assembly of eukaryotic cytochrome c oxidase. At variance with Sco1, Cox17 orthologs are found only in eukaryotes. We browsed bacterial genomes to search proteins functionally equivalent to Cox17, and we identified a class of proteins of unknown function displaying a conserved gene neighborhood to bacterial Sco1 genes, all sharing a potential metal binding motif H( M) X10MX21HXM. Two members of this group, DR1885 from Deinococcus radiodurans and CC3502 from Caulobacter crescentus, were expressed, and their interaction with copper was investigated. The solution structure and extended x-ray absorption fine structure data on the former protein reveal that the protein binds copper(I) through a histidine and three Mets in a cupredoxin-like fold. The surface location of the copper-binding site as well as the type of coordination are well poised for metal transfer chemistry, suggesting that DR1885 might transfer copper, taking the role of Cox17 in bacteria. On the basis of our results, a possible pathway for copper delivery to the CuAcenter in bacteria is proposed.