title: Structure and interactions of the C-terminal metal binding domain of Archaeoglobus fulgidus CopA.
abstract: The Cu(+)-ATPase CopA from Archaeoglobus fulgidus belongs to the P(1B) family of the P-type ATPases. These integral membrane proteins couple the energy of ATP hydrolysis to heavy metal ion translocation across membranes. A defining feature of P(1B-1)-type ATPases is the presence of soluble metal binding domains at the N-terminus (N-MBDs). The N-MBDs exhibit a conserved ferredoxin-like fold, similar to that of soluble copper chaperones, and bind metal ions via a conserved CXXC motif. The N-MBDs enable Cu(+) regulation of turnover rates apparently through Cu-sensitive interactions with catalytic domains. A. fulgidus CopA is unusual in that it contains both an N-terminal MBD and a C-terminal MBD (C-MBD). The functional role of the unique C-MBD has not been established. Here, we report the crystal structure of the apo, oxidized C-MBD to 2.0 A resolution. In the structure, two C-MBD monomers form a domain-swapped dimer, which has not been observed previously for similar domains. In addition, the interaction of the C-MBD with the other cytoplasmic domains of CopA, the ATP binding domain (ATPBD) and actuator domain (A-domain), has been investigated. Interestingly, the C-MBD interacts specifically with both of these domains, independent of the presence of Cu(+) or nucleotides. These data reinforce the uniqueness of the C-MBD and suggest a distinct structural role for the C-MBD in CopA transport.
authors.affiliation: Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Sorabh
authors.initials: S
authors.lastname: Agarwal
authors.forename: Deli
authors.initials: D
authors.lastname: Hong
authors.forename: Nirav K
authors.initials: NK
authors.lastname: Desai
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Sazinsky
authors.forename: José M
authors.initials: JM
authors.lastname: Argüello
authors.forename: Amy C
authors.initials: AC
authors.lastname: Rosenzweig
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D019611:Archaeoglobus fulgidus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D003460:Crystallization; D004591:Electrophoresis, Polyacrylamide Gel; D054730:Protein Interaction Domains and Motifs
chemical_list: D001426:Bacterial Proteins; C071263:CopA protein, Bacteria; D003300:Copper; D000255:Adenosine Triphosphate