title: Solution structure of the yeast copper transporter domain Ccc2a in the apo and Cu(I)-loaded states.
abstract: Ccc2 is an intracellular copper transporter in Saccharomyces cerevisiae and is a physiological target of the copper chaperone Atx1. Here we describe the solution structure of the first N-terminal MTCXXC metal-binding domain, Ccc2a, both in the presence and absence of Cu(I). For Cu(I)-Ccc2a, 1944 meaningful nuclear Overhauser effects were used to obtain a family of 35 structures with root mean square deviation to the average structure of 0.36 +/- 0.06 A for the backbone and 0.79 +/- 0.05 A for the heavy atoms. For apo-Ccc2a, 1970 meaningful nuclear Overhauser effects have been used with 35 (3)J(HNHalpha) to obtain a family of 35 structures with root mean square deviation to the average structure of 0.38 +/- 0.06 A for the backbone and 0.82 +/- 0.07 A for the heavy atoms. The protein exhibits a betaalphabetabetaalphabeta, ferrodoxin-like fold similar to that of its target Atx1 and that of a human counterpart, the fourth metal-binding domain of the Menkes protein. The overall fold remains unchanged upon copper loading, but the copper-binding site itself becomes less disordered. The helical context of the copper-binding site, and the copper-induced conformational changes in Ccc2a differ from those in Atx1. Ccc2a presents a conserved acidic surface which complements the basic surface of Atx1 and a hydrophobic surface. These results open new mechanistic aspects of copper transporter domains with physiological copper donor and acceptor proteins.
authors.affiliation: Magnetic Resonance Center and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, Sesto Fiorentino, Florence, 50019, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Banci
authors.forename: I
authors.initials: I
authors.lastname: Bertini
authors.forename: S
authors.initials: S
authors.lastname: Ciofi-Baffoni
authors.forename: D L
authors.initials: DL
authors.lastname: Huffman
authors.forename: T V
authors.initials: TV
authors.lastname: O'Halloran
mesh_terms: D000595:Amino Acid Sequence; D027682:Cation Transport Proteins; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D000079922:Copper Transport Proteins; D005656:Fungal Proteins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D012996:Solutions; D055672:Static Electricity
chemical_list: C092974:CCC2 protein, S cerevisiae; D027682:Cation Transport Proteins; D000079922:Copper Transport Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D012996:Solutions; D003300:Copper