Characterization of the Binding Interface between the Copper Chaperone Atx1 and the First Cytosolic Domain of Ccc2 ATPase

Arnesano, Fabio; Banci, Lucia; Bertini, Ivano; Cantini, Francesca; Ciofi‐Baffoni, Simone; Huffman, David L.; O’Halloran, Thomas V.

doi:10.1074/jbc.m104807200

Cited by 144 publications

(184 citation statements)

References 69 publications

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“…Characteristic residues discussed in the text and highlighted in Fig. 1 are shown in brown space-filling representation and are labeled site would be in favorable position to capture copper from copper-loaded chaperones, which presumably donate copper to the ATPase (Arnesano et al 2001(Arnesano et al , 2004.…”

Section: Resultsmentioning

confidence: 99%

Structural model of the CopA copper ATPase of Enterococcus hirae based on chemical cross-linking

et al. 2008

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The CopA copper ATPase of Enterococcus hirae belongs to the family of heavy metal pumping CPx-type ATPases and shares 43% sequence similarity with the human Menkes and Wilson copper ATPases. Due to a lack of suitable protein crystals, only partial three-dimensional structures have so far been obtained for this family of ion pumps. We present a structural model of CopA derived by combining topological information obtained by intramolecular cross-linking with molecular modeling. Purified CopA was crosslinked with different bivalent reagents, followed by tryptic digestion and identification of cross-linked peptides by mass spectrometry. The structural proximity of tryptic fragments provided information about the structural arrangement of the hydrophilic protein domains, which was integrated into a three-dimensional model of CopA. Comparative modeling of CopA was guided by the sequence similarity to the calcium ATPase of the sarcoplasmic reticulum, Serca1, for which detailed structures are available. In addition, known partial structures of CPx-ATPase homologous to CopA were used as modeling templates. A docking approach was used to predict the orientation of the heavy metal binding domain of CopA relative to the core structure, which was verified by distance constraints derived from cross-links. The overall structural model of CopA resembles the Serca1 structure, but reveals distinctive features of CPx-type ATPases. A prominent feature is the positioning of the heavy metal binding domain. It features an orientation of the Cu binding ligands which is appropriate for the interaction with Cu-loaded metallochaperones in solution. Moreover, a novel model of the architecture of the intramembranous Cu binding sites could be derived.

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Section: Resultsmentioning

confidence: 99%

Structural model of the CopA copper ATPase of Enterococcus hirae based on chemical cross-linking

et al. 2008

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“…Within this frame, we may speculate that the water molecule interacting with the solvent accessible Cu(II) ion in site A can be displaced by Met residues, either from CopA, CopB or from site B of a second CopC molecule in a head-tail interaction, but that only copper reduction triggers metal transfer to the new Met-rich site, having higher affinity for Cu(I). If the two sites with different affinity for the two redox states of copper are nearby, the mechanism of copper release and uptake occurs in a protective local environment, reminiscent of that of metallochaperones (52,53), ensuring a safer metal transfer in the periplasmic space.…”

Section: Discussionmentioning

confidence: 99%

A redox switch in CopC: An intriguing copper trafficking protein that binds copper(I) and copper(II) at different sites

Arnesano

Banci

Bertini

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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“…Although this finding may be because of the presence of a glutathione S-transferase tag (33), it could also result from the two domains coordinating a single Cu(I) ion. Because the binding surface of the target domain is proposed to involve regions near the CXXC motif (15,37), coordination of a single Cu(I) ion between the CXXC motifs in MNK domains 1 and 2 could hinder Atox1 access.…”

Section: Discussionmentioning

confidence: 99%

“…Consideration of the electrostatic properties of each domain furnishes part of the answer. Interactions between Atox1 or Atx1 and their target domains involve complementary electrostatic surfaces (15,16,37,48). In particular, positively charged residues on the chaperone surface interact with negatively charged residues on the target domain.…”

Section: Discussionmentioning

confidence: 99%

Binding of Copper(I) by the Wilson Disease Protein and Its Copper Chaperone

Wernimont¹,

Yatsunyk

Rosenzweig

2004

Journal of Biological Chemistry

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The Wilson disease protein (WND) is a transport ATPase involved in copper delivery to the secretory pathway. Mutations in WND and its homolog, the Menkes protein, lead to genetic disorders of copper metabolism. The WND and Menkes proteins are distinguished from other P-type ATPases by the presence of six soluble N-terminal metal-binding domains containing a conserved CXXC metal-binding motif. The exact roles of these domains are not well established, but possible functions include exchanging copper with the metallochaperone Atox1 and mediating copper-responsive cellular relocalization. Although all six domains can bind copper, genetic and biochemical studies indicate that the domains are not functionally equivalent. One way the domains could be tuned to perform different functions is by having different affinities for Cu(I). We have used isothermal titration calorimetry to measure the association constant (K a ) and stoichiometry (n) values of Cu(I) binding to the WND metal-binding domains and to their metallochaperone Atox1. The association constants for both the chaperone and target domains are ϳ10 5 to 10 6 M ؊1 , suggesting that the handling of copper by Atox1 and copper transfer between Atox1 and WND are under kinetic rather than thermodynamic control. Although some differences in both n and K a values are observed for variant proteins containing less than the full complement of six metal-binding domains, the data for domains 1-6 were best fitted with a single site model. Thus, the individual functions of the six WND metal-binding domains are not conferred by different Cu(I) affinities but instead by fold and electrostatic surface properties.

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Characterization of the Binding Interface between the Copper Chaperone Atx1 and the First Cytosolic Domain of Ccc2 ATPase

Cited by 144 publications

References 69 publications

Structural model of the CopA copper ATPase of Enterococcus hirae based on chemical cross-linking

Structural model of the CopA copper ATPase of Enterococcus hirae based on chemical cross-linking

A redox switch in CopC: An intriguing copper trafficking protein that binds copper(I) and copper(II) at different sites

Binding of Copper(I) by the Wilson Disease Protein and Its Copper Chaperone

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