151
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Shao Z, Sun F. Intracellular sequestration of manganese and phosphorus in a metal-resistant fungus Cladosporium cladosporioides from deep-sea sediment. Extremophiles 2007; 11:435-43. [PMID: 17265162 DOI: 10.1007/s00792-006-0051-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Accepted: 11/21/2006] [Indexed: 10/23/2022]
Abstract
A heavy metal resistant fungus was isolated from the sediment of Pacific Ocean, and identified to be Cladosporium cladosporioides. It grew normally in a medium containing 60 mM Mn(2+) and could endure 1,200 mM as the highest concentration tested. Quantification analysis confirmed a high accumulation of Mn which was 58 mg/g in dried biomass. Under transmission electron microscope, many intracellular crystals were observed in the cytoplasm of the hypha cells grown in a Mn-rich medium, and varied from a few nanometers to 200 nm in length. Energy dispersive X-ray (EDX) analysis showed that the crystals were composed of manganese and phosphorus in atomic ratio of 1.6:1 (Mn/P). Further, factors which might influence the resistance of this fungus were investigated. As a result, its high resistance to Mn(2+) was found dependent on the presence of Mg(2+), and could be further enhanced by phosphate. However, the effect of phosphate was not observed without the presence of Mg(2+). In addition, the resistance was also influenced by pH of the medium, which was lost above pH 8. This is the first report on a fungus which showed a hyper resistance to manganese by forming a large quantity of intracellular Mn/P crystals.
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Affiliation(s)
- Zongze Shao
- Key Lab of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Daxue Road 178#, 361005, Xiamen, Fujian, China.
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152
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Yatsunyk LA, Rosenzweig AC. Cu(I) binding and transfer by the N terminus of the Wilson disease protein. J Biol Chem 2007; 282:8622-31. [PMID: 17229731 DOI: 10.1074/jbc.m609533200] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Wilson and Menkes diseases are genetic disorders of copper metabolism caused by mutations in the Wilson (WND) and Menkes (MNK) copper-transporting P1B-type ATPases. The N termini of these ATPases consist of six metal binding domains (MBDs). The MBDs interact with the copper chaperone Atox1 and are believed to play roles in catalysis and in copper-mediated cellular relocalization of WND and MNK. Although all six MBDs have similar folds and bind one Cu(I) ion via a conserved CXXC motif, biochemical and genetic data suggest that they have distinct functions. Most studies aimed at characterizing the MBDs have employed smaller polypeptides consisting of one or two domains. The role of each MBD is probably defined by its environment within the six-domain N terminus, however. To study the properties of the individual domains within the context of the intact Wilson N terminus (N-WND), a series of variants in which five of the six metal binding CXXC motifs are mutated to SXXS was generated. For each variant, the Cu(I) binding affinity and the ability to exchange Cu(I) with Atox1 were investigated. The results indicate that Atox1 can deliver Cu(I) to and remove Cu(I) from each MBD, that each MBD has stronger Cu(I) retention properties than Atox1, and that all of the MBDs as well as Atox1 have similar K(Cu) values of (2.2-6.3) x 10(10) m(-1). Therefore, the specific role of each MBD is not conferred by its position within the intact N-WND but may be related to interactions with other domains and partner proteins.
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Affiliation(s)
- Liliya A Yatsunyk
- Department of Biochemistry, Northwestern University, Evanston, Illinois 60208, USA
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153
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Singleton C, Le Brun NE. Atx1-like chaperones and their cognate P-type ATPases: copper-binding and transfer. Biometals 2007; 20:275-89. [PMID: 17225061 DOI: 10.1007/s10534-006-9068-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 11/28/2006] [Indexed: 01/05/2023]
Abstract
Copper is an essential yet toxic metal ion. To satisfy cellular requirements, while, at the same time, minimizing toxicity, complex systems of copper trafficking have evolved in all cell types. The best conserved and most widely distributed of these involve Atx1-like chaperones and P(1B)-type ATPase transporters. Here, we discuss current understanding of how these chaperones bind Cu(I) and transfer it to the Atx1-like N-terminal domains of their cognate transporter.
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Affiliation(s)
- Chloe Singleton
- Centre for Metalloprotein Spectroscopy and Biology, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, NR4 7TJ, UK
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154
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Argüello JM, Eren E, González-Guerrero M. The structure and function of heavy metal transport P1B-ATPases. Biometals 2007; 20:233-48. [PMID: 17219055 DOI: 10.1007/s10534-006-9055-6] [Citation(s) in RCA: 243] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Accepted: 11/28/2006] [Indexed: 10/23/2022]
Abstract
P(1B)-type ATPases transport heavy metals (Cu+, Cu2+, Zn2+, Co2+, Cd2+, Pb2+) across membranes. Present in most organisms, they are key elements for metal homeostasis. P(1B)-type ATPases contain 6-8 transmembrane fragments carrying signature sequences in segments flanking the large ATP binding cytoplasmic loop. These sequences made possible the differentiation of at least four P(1B)-ATPase subgroups with distinct metal selectivity: P(1B-1): Cu+, P(1B-2): Zn2+, P(1B-3): Cu2+, P(1B-4): Co2+. Mutagenesis of the invariant transmembrane Cys in H6, Asn and Tyr in H7 and Met and Ser in H8 of the Archaeoglobus fulgidus Cu+-ATPase has revealed that their side chains likely coordinate the metals during transport and constitute a central unique component of these enzymes. The structure of various cytoplasmic domains has been solved. The overall structure of those involved in enzyme phosphorylation (P-domain), nucleotide binding (N-domain) and energy transduction (A-domain), appears similar to those described for the SERCA Ca2+-ATPase. However, they show different features likely associated with singular functions of these proteins. Many P(1B)-type ATPases, but not all of them, also contain a diverse arrangement of cytoplasmic metal binding domains (MBDs). In spite of their structural differences, all N- and C-terminal MBDs appear to control the enzyme turnover rate without affecting metal binding to transmembrane transport sites. In addition, eukaryotic Cu+-ATPases have multiple N-MBD regions that participate in the metal dependent targeting and localization of these proteins. The current knowledge of structure-function relationships among the different P(1B)-ATPases allows for a description of selectivity, regulation and transport mechanisms. Moreover, it provides a framework to understand mutations in human Cu+-ATPases (ATP7A and ATP7B) that lead to Menkes and Wilson diseases.
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Affiliation(s)
- José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Rd., Worcester, MA 01609, USA.
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155
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Lin CH, Chin KH, Gao FP, Lyu PC, Shr HL, Wang AHJ, Chou SH. Cloning, crystallization and preliminary X-ray studies of XC2981 from Xanthomonas campestris, a putative CutA1 protein involved in copper-ion homeostasis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:1113-5. [PMID: 17077491 PMCID: PMC2225225 DOI: 10.1107/s1744309106039832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2006] [Accepted: 09/28/2006] [Indexed: 01/08/2023]
Abstract
Divalent metal ions play key roles in all living organisms, serving as cofactors for many proteins involved in a variety of electron-transfer activities. However, copper ions are highly toxic when an excessive amount is accumulated in a cell. CutA1 is a protein found in all kingdoms of life that is believed to participate in copper-ion tolerance in Escherichia coli, although its specific function remains unknown. Several crystal structures of multimeric CutA1 with different rotation angles and degrees of interaction between trimer interfaces have been reported. Here, the cloning, expression, crystallization and preliminary X-ray analysis of XC2981, a possible CutA1 protein present in the plant pathogen Xanthomonas campestris, are reported. The XC2981 crystals diffracted to a resolution of 2.6 A. They are cubic and belong to space group I23, with unit-cell parameters a = b = c = 130.73 A.
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Affiliation(s)
- Chien-Hung Lin
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan
| | - Ko-Hsin Chin
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan
| | | | - Ping-Chiang Lyu
- Department of Life Science, National Tsing Hua University, Hsin-Chu, Taiwan
| | - Hui-Lin Shr
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei, Taiwan
- Core Facility for Protein Crystallography, Academia Sinica, Nankang, Taipei, Taiwan
| | - Andrew H.-J. Wang
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei, Taiwan
- Core Facility for Protein Crystallography, Academia Sinica, Nankang, Taipei, Taiwan
| | - Shan-Ho Chou
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan
- Correspondence e-mail:
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156
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Eren E, Kennedy DC, Maroney MJ, Argüello JM. A novel regulatory metal binding domain is present in the C terminus of Arabidopsis Zn2+-ATPase HMA2. J Biol Chem 2006; 281:33881-91. [PMID: 16973620 DOI: 10.1074/jbc.m605218200] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HMA2 is a Zn2+-ATPase from Arabidopsis thaliana. It contributes to the maintenance of metal homeostasis in cells by driving Zn2+ efflux. Distinct from P1B-type ATPases, plant Zn2+-ATPases have long C-terminal sequences rich in Cys and His. Removal of the 244 amino acid C terminus of HMA2 leads to a 43% reduction in enzyme turnover without significant effect on the Zn2+ K(1/2) for enzyme activation. Characterization of the isolated HMA2 C terminus showed that this fragment binds three Zn2+ with high affinity (Kd = 16 +/- 3 nM). Circular dichroism spectral analysis indicated the presence of 8% alpha-helix, 45% beta-sheet, and 48% random coil in the C-terminal peptide with noticeable structural changes upon metal binding (8% alpha-helix, 39% beta-sheet, and 52% random coil). Zn K-edge XAS of Zn-C-MBD in the presence of one equivalent of Zn2+ shows that the average zinc complex formed is composed of three His and one Cys residues. Upon the addition of two extra Zn2+ ions per C-MBD, these appear coordinated primarily by His residues thus, suggesting that the three Zn2+ binding domains might not be identical. Modification of His residues with diethyl pyrocarbonate completely inhibited Zn2+ binding to the C terminus, pointing out the importance of His residues in Zn2+ coordination. In contrast, alkylation of Cys with iodoacetic acid did not prevent Zn2+ binding to the HMA2 C terminus. Zn K-edge XAS of the Cys-alkylated protein was consistent with (N/O)4 coordination of the zinc site, with three of those ligands fitting for His residues. In summary, plant Zn2+-ATPases contain novel metal binding domains in their cytoplasmic C terminus. Structurally distinct from the well characterized N-terminal metal binding domains present in most P1B-type ATPases, they also appear to regulate enzyme turnover rate.
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Affiliation(s)
- Elif Eren
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA
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157
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Banci L, Bertini I, Cantini F, DellaMalva N, Herrmann T, Rosato A, Wüthrich K. Solution structure and intermolecular interactions of the third metal-binding domain of ATP7A, the Menkes disease protein. J Biol Chem 2006; 281:29141-7. [PMID: 16873374 DOI: 10.1074/jbc.m603176200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The third metal-binding domain of the human Menkes protein (MNK3), a copper(I)-transporting ATPase, has been expressed in Escherichia coli and characterized in solution. The solution structure of MNK3, its copper(I)-binding properties, and its interaction with the physiological partner, HAH1, have been studied. MNK3 is the domain most dissimilar in structure from the other domains of the Menkes protein. This is reflected in a significant rearrangement of the last strand of the four-stranded beta-sheet when compared with the other known homologous proteins or protein domains. MNK3 is also peculiar with respect to its interaction with the copper(I) ion, as it was found to be a comparatively weak binder. Copper(I) transfer from metal-loaded HAH1 was observed experimentally, but the metal distribution was shifted toward binding by HAH1. This is at variance with what is observed for the other Menkes domains.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
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158
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Pilon M, Abdel-Ghany SE, Cohu CM, Gogolin KA, Ye H. Copper cofactor delivery in plant cells. CURRENT OPINION IN PLANT BIOLOGY 2006; 9:256-63. [PMID: 16616609 DOI: 10.1016/j.pbi.2006.03.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Accepted: 03/22/2006] [Indexed: 05/08/2023]
Abstract
Copper (Cu) is a micronutrient that has roles in photosynthesis, respiration, antioxidant activity, cell wall metabolism and hormone perception. Excess Cu is toxic and therefore its delivery has to be tightly regulated. Recent progress in the study of Cu homeostasis has revealed not only components of the Cu delivery machinery but also regulatory systems that control Cu-protein expression and coordinate the activity of Cu-delivery systems. The response of photosynthetic organisms to Cu deficiency indicates the existence of cross-talk between metal cofactor delivery pathways. Next to its well-established roles in plant metabolism, a novel function for Cu, first discovered in plants, is in the biogenesis of molybdenum cofactor. Defects in Cu delivery factors also suggest important roles for Cu in cell expansion.
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Affiliation(s)
- Marinus Pilon
- Biology Department and Program in Molecular Plant Biology, Colorado State University, Fort Collins, Colorado 80523-1878, USA.
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159
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Gaggelli E, Kozlowski H, Valensin D, Valensin G. Copper Homeostasis and Neurodegenerative Disorders (Alzheimer's, Prion, and Parkinson's Diseases and Amyotrophic Lateral Sclerosis). Chem Rev 2006; 106:1995-2044. [PMID: 16771441 DOI: 10.1021/cr040410w] [Citation(s) in RCA: 1239] [Impact Index Per Article: 68.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Elena Gaggelli
- Department of Chemistry, University of Siena, Via Aldo Moro 2, Siena 53100, Italy
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160
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Arnesano F, Banci L, Bertini I, Capozzi F, Ciofi-Baffoni S, Ciurli S, Luchinat C, Mangani S, Rosato A, Turano P, Viezzoli MS. An Italian contribution to structural genomics: Understanding metalloproteins. Coord Chem Rev 2006. [DOI: 10.1016/j.ccr.2006.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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161
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Banci L, Bertini I, Ciofi-Baffoni S, Kandias NG, Robinson NJ, Spyroulias GA, Su XC, Tottey S, Vanarotti M. The delivery of copper for thylakoid import observed by NMR. Proc Natl Acad Sci U S A 2006; 103:8320-5. [PMID: 16707580 PMCID: PMC1482492 DOI: 10.1073/pnas.0600142103] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The thylakoid compartments of plant chloroplasts are a vital destination for copper. Copper is needed to form holo-plastocyanin, which must shuttle electrons between photosystems to convert light into biologically useful chemical energy. Copper can bind tightly to proteins, so it has been hypothesized that copper partitions onto ligand-exchange pathways to reach intracellular locations without inflicting damage en route. The copper metallochaperone Atx1 of chloroplast-related cyanobacteria (ScAtx1) engages in bacterial two-hybrid interactions with N-terminal domains of copper-transporting ATPases CtaA (cell import) and PacS (thylakoid import). Here we visualize copper delivery. The N-terminal domain PacS(N) has a ferredoxin-like fold that forms copper-dependent heterodimers with ScAtx1. Removal of copper, by the addition of the cuprous-ion chelator bathocuproine disulfonate, disrupts this heterodimer, as shown from a reduction of the overall tumbling rate of the protein mixture. The NMR spectral changes of the heterodimer versus the separate proteins reveal that loops 1, 3, and 5 (the carboxyl tail) of the ScAtx1 Cu(I) site switch to an apo-like configuration in the heterodimer. NMR data ((2)J(NH) couplings in the imidazole ring of (15)N ScAtx1 His-61) also show that His-61, bound to copper(I) in [Cu(I)ScAtx1](2), is not coordinated to copper in the heterodimer. A model for the PacS(N)/Cu(I)/ScAtx1 complex is presented. Contact with PacS(N) induces change to the ScAtx1 copper-coordination sphere that drives copper release for thylakoid import. These data also elaborate on the mechanism to keep copper(I) out of the ZiaA(N) ATPase zinc sites.
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Affiliation(s)
- Lucia Banci
- *Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Ivano Bertini
- *Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- To whom correspondence should be addressed. E-mail:
| | - Simone Ciofi-Baffoni
- *Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Nikolaos G. Kandias
- *Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Nigel J. Robinson
- Department of Cell and Molecular Bioscience, Medical School, University of Newcastle, Newcastle upon Tyne NE2 4HH, United Kingdom; and
| | - Georgios A. Spyroulias
- *Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
- Department of Pharmacy, School of Health Sciences, University of Patras, GR-26500 Rion, Patras, Greece
| | - Xun-Cheng Su
- *Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Stephen Tottey
- Department of Cell and Molecular Bioscience, Medical School, University of Newcastle, Newcastle upon Tyne NE2 4HH, United Kingdom; and
| | - Murugendra Vanarotti
- *Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
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162
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Kung CCS, Huang WN, Huang YC, Yeh KC. Proteomic survey of copper-binding proteins inArabidopsis roots by immobilized metal affinity chromatography and mass spectrometry. Proteomics 2006; 6:2746-58. [PMID: 16526091 DOI: 10.1002/pmic.200500108] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
To plants, copper is vitally essential at low concentrations but extremely toxic at elevated concentrations. Plants have evolved a suite of mechanisms that modulate the uptake, distribution, and utilization of copper ions. These mechanisms require copper-interacting proteins for transporting, chelating, and sequestrating copper ions. In this study, we have systematically screened for copper-interacting proteins in Arabidopsis roots via copper-immobilized metal affinity chromatography (Cu-IMAC). We also compared Arabidopsis root metalloproteomes with affinity to Cu-IMAC and Zn-IMAC. From the identities of 38 protein spots with affinity to Cu-IMAC, 35 unique proteins were identified. Functional classification of these proteins includes redox/hydrolytic reactions, amino acid metabolism, glutathione metabolism, phosphorylation, translation machinery, membrane-associated proteins, and vegetative storage proteins. Potential copper-interacting motifs were predicted and scored. Six candidate motifs, H-(X)5 -H, H-(X)7 -H, H-(X)12 -H, H-(X)6 -M, M-(X)7 -H, and H-(X)3 -C, are present in Cu-IMAC-isolated proteins with higher frequency than in the whole Arabidopsis proteome.
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Affiliation(s)
- Cheng-Che S Kung
- Institute of BioAgricultural Sciences, Academia Sinica, Taipei, Taiwan, Republic of China
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163
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Achila D, Banci L, Bertini I, Bunce J, Ciofi-Baffoni S, Huffman DL. Structure of human Wilson protein domains 5 and 6 and their interplay with domain 4 and the copper chaperone HAH1 in copper uptake. Proc Natl Acad Sci U S A 2006; 103:5729-34. [PMID: 16571664 PMCID: PMC1458641 DOI: 10.1073/pnas.0504472103] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Indexed: 12/16/2022] Open
Abstract
Human Wilson protein is a copper-transporting ATPase located in the secretory pathway possessing six N-terminal metal-binding domains. Here we focus on the function of the metal-binding domains closest to the vesicular portion of the copper pump, i.e., domain 4 (WLN4), and a construct of domains 5 and 6 (WLN5-6). For comparison purposes, some experiments were also performed with domain 2 (WLN2). The solution structure of apoWLN5-6 consists of two ferredoxin folds connected by a short linker, and (15)N relaxation rate measurements show that it behaves as a unit in solution. An NMR titration of apoWLN5-6 with the metallochaperone Cu(I)HAH1 reveals no complex formation and no copper exchange between the two proteins, whereas titration of Cu(I)HAH1 with WLN4 shows the formation of an adduct that is in fast exchange on the NMR time scale with the isolated protein species as confirmed by (15)N relaxation data. A similar interaction is also observed between Cu(I)HAH1 and WLN2; however, the relative amount of the adduct in the protein mixture is lower. An NMR titration of apoWLN5-6 with Cu(I)WLN4 shows copper transfer, first to WLN6 then to WLN5, without the formation of an adduct. Therefore, we suggest that WLN4 and WLN2 are two acceptors of Cu(I) from HAH1, which then somehow route copper to WLN5-6, before the ATP-driven transport of copper across the vesicular membrane.
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Affiliation(s)
- David Achila
- *Department of Chemistry, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5413; and
| | - Lucia Banci
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, Sesto Fiorentino, 50019 Florence, Italy
| | - Ivano Bertini
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, Sesto Fiorentino, 50019 Florence, Italy
| | - Jennifer Bunce
- *Department of Chemistry, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5413; and
| | - Simone Ciofi-Baffoni
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, Sesto Fiorentino, 50019 Florence, Italy
| | - David L. Huffman
- *Department of Chemistry, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5413; and
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164
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Banci L, Bertini I, Ciofi-Baffoni S, Su XC, Miras R, Bal N, Mintz E, Catty P, Shokes JE, Scott RA. Structural basis for metal binding specificity: the N-terminal cadmium binding domain of the P1-type ATPase CadA. J Mol Biol 2005; 356:638-50. [PMID: 16388822 PMCID: PMC3562998 DOI: 10.1016/j.jmb.2005.11.055] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2005] [Revised: 11/17/2005] [Accepted: 11/17/2005] [Indexed: 11/16/2022]
Abstract
In bacteria, P1-type ATPases are responsible for resistance to di- and monovalent toxic heavy metals by taking them out of the cell. These ATPases have a cytoplasmic N terminus comprising metal binding domains defined by a betaalphabetabetaalphabeta fold and a CXXC metal binding motif. To check how the structural properties of the metal binding site in the N terminus can influence the metal specificity of the ATPase, the first structure of a Cd(II)-ATPase N terminus was determined by NMR and its coordination sphere was investigated by X-ray absorption spectroscopy. A novel metal binding environment was found, comprising the two conserved Cys residues of the metal binding motif and a Glu in loop 5. A bioinformatic search identifies an ensemble of highly homologous sequences presumably with the same function. Another group of highly homologous sequences is found which can be referred to as zinc-detoxifying P1-type ATPases with the metal binding pattern DCXXC in the N terminus. Because no carboxylate groups participate in Cu(I) or Ag(I) binding sites, we suggest that the acidic residue plays a key role in the coordination properties of divalent cations, hence conferring a function to the N terminus in the metal specificity of the ATPase.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6 50019 Sesto Fiorentino, Florence, Italy
| | - Ivano Bertini
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6 50019 Sesto Fiorentino, Florence, Italy
- Corresponding authors: ;
| | - Simone Ciofi-Baffoni
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6 50019 Sesto Fiorentino, Florence, Italy
| | - Xun-Cheng Su
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6 50019 Sesto Fiorentino, Florence, Italy
| | - Roger Miras
- Laboratoire de Biophysique Moléculaire et Cellulaire UMR 5090 CEA-CNRS-Université Joseph Fourier CEA/DRDC/BMC, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
| | - Nathalie Bal
- Laboratoire de Biophysique Moléculaire et Cellulaire UMR 5090 CEA-CNRS-Université Joseph Fourier CEA/DRDC/BMC, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
| | - Elisabeth Mintz
- Laboratoire de Biophysique Moléculaire et Cellulaire UMR 5090 CEA-CNRS-Université Joseph Fourier CEA/DRDC/BMC, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
| | - Patrice Catty
- Laboratoire de Biophysique Moléculaire et Cellulaire UMR 5090 CEA-CNRS-Université Joseph Fourier CEA/DRDC/BMC, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
- Corresponding authors: ;
| | - Jacob E. Shokes
- Center for Metalloenzyme Studies and the Department of Chemistry, University of Georgia, Athens, GA 30602-2556 USA
| | - Robert A. Scott
- Center for Metalloenzyme Studies and the Department of Chemistry, University of Georgia, Athens, GA 30602-2556 USA
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165
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Poger D, Fuchs JF, Nedev H, Ferrand M, Crouzy S. Molecular dynamics study of the metallochaperone Hah1 in its apo and Cu(I)-loaded states: role of the conserved residue M10. FEBS Lett 2005; 579:5287-92. [PMID: 16194538 DOI: 10.1016/j.febslet.2005.08.052] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Revised: 08/05/2005] [Accepted: 08/19/2005] [Indexed: 10/25/2022]
Abstract
Molecular dynamics simulations were performed on both apo and copper forms of the human copper chaperone, Hah1. Wild-type Hah1 and a methionine (M10) to serine mutant were investigated. We have evidenced the central role of residue M10 in stabilizing the hydrophobic core of Hah1 as well as the internal structure of the metal-binding site. When copper(I) is bound, the mobility of Hah1 is reduced whereas mutation of M10 implies a drastic increase of the mobility of apoHah1, stressing the importance of this highly conserved hydrophobic residue for copper sequestration by the apoprotein.
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Affiliation(s)
- David Poger
- Laboratoire de Biophysique Moléculaire et Cellulaire, Département de Réponse et Dynamique Cellulaires, Commissariat à l'Energie Atomique, Grenoble, France
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166
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Banci L, Bertini I, Ciofi-Baffoni S, Chasapis CT, Hadjiliadis N, Rosato A. An NMR study of the interaction between the human copper(I) chaperone and the second and fifth metal-binding domains of the Menkes protein. FEBS J 2005; 272:865-71. [PMID: 15670166 DOI: 10.1111/j.1742-4658.2004.04526.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The interaction between the human copper(I) chaperone, HAH1, and one of its two physiological partners, the Menkes disease protein (ATP7A), was investigated in solution using heteronuclear NMR. The study was carried out through titrations involving HAH1 and either the second or the fifth soluble domains of ATP7A (MNK2 and MNK5, respectively), in the presence of copper(I). The copper-transfer properties of MNK2 and MNK5 are similar, and differ significantly from those previously observed for the yeast homologous system. In particular, no stable adduct is formed between either of the MNK domains and HAH1. The copper(I) transfer reaction is slow on the time scale of the NMR chemical shift, and the equilibrium is significantly shifted towards the formation of copper(I)-MNK2/MNK5. The solution structures of both apo- and copper(I)-MNK5, which were not available, are also reported. The results are discussed in comparison with the data available in the literature for the interaction between HAH1 and its partners from other spectroscopic techniques.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center (CERM), University of Florence, Italy
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167
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Morin I, Cuillel M, Lowe J, Crouzy S, Guillain F, Mintz E. Cd2+- or Hg2+-binding proteins can replace the Cu+-chaperone Atx1 in delivering Cu+to the secretory pathway in yeast. FEBS Lett 2005; 579:1117-23. [PMID: 15710399 DOI: 10.1016/j.febslet.2005.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Revised: 01/04/2005] [Accepted: 01/04/2005] [Indexed: 10/25/2022]
Abstract
Copper delivery to Ccc2--the Golgi Cu+-ATPase--was investigated in vivo, replacing the Cu+-chaperone Atx1 by various structural homologues in an atx1-Delta yeast strain. Various proteins, displaying the same ferredoxin-like fold and (M/L)(T/S)CXXC metal-binding motif as Atx1 and known as Cu+-, Cd2+- or Hg2+-binding proteins were able to replace Atx1. Therefore, regardless of their original function, these proteins could all bind copper and transfer it to Ccc2, suggesting that Ccc2 is opportunistic and can interact with many different proteins to gain Cu+. The possible role of electrostatic potential surfaces in the docking of Ccc2 with these Atx1-homologues is discussed.
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Affiliation(s)
- Isabelle Morin
- Laboratoire de Biophysique Moléculaire et Cellulaire, UMR 5090 CEA-CNRS-Université Joseph Fourier, CEA/DRDC/BMC, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
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168
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Tanchou V, Gas F, Urvoas A, Cougouluègne F, Ruat S, Averseng O, Quéméneur E. Copper-mediated homo-dimerisation for the HAH1 metallochaperone. Biochem Biophys Res Commun 2004; 325:388-94. [PMID: 15530404 DOI: 10.1016/j.bbrc.2004.10.048] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Indexed: 11/24/2022]
Abstract
The HAH1 metallochaperone is a key protein implicated in copper homeostasis in human cells. Using as solid-phase based assay completed with Biacore studies, we provided evidence that HAH1 forms homo-dimers in the presence of copper. Biacore analysis allowed us to determine the kinetic parameters of this interaction, characterised by an apparent affinity constant of 6muM. Moreover, we demonstrated that copper-loaded HAH1 interacts independently with each of the six individual metal-binding domains of the copper-translocating Menkes ATPase. Finally, the homo-dimerisation of the metallochaperone was confirmed in living cells by using fluorescence resonance energy transfer. Results have been discussed in the context of intracellular copper control.
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Affiliation(s)
- Valérie Tanchou
- CEA VALRHO, Département d'Ingénierie et d'Etudes des Protéines, Service de Biochimie Post-génomique et Toxicologie Nucléaire, BP1717, 30207 Bagnols sur Cèze cedex, France.
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169
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Mandal AK, Yang Y, Kertesz TM, Argüello JM. Identification of the transmembrane metal binding site in Cu+-transporting PIB-type ATPases. J Biol Chem 2004; 279:54802-7. [PMID: 15494391 DOI: 10.1074/jbc.m410854200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
P(IB)-type ATPases have an essential role maintaining copper homeostasis. Metal transport by these membrane proteins requires the presence of a transmembrane metal occlusion/binding site. Previous studies showed that Cys residues in the H6 transmembrane segment are required for metal transport. In this study, the participation in metal binding of conserved residues located in transmembrane segments H7 and H8 was tested using CopA, a model Cu(+)-ATPase from Archaeoglobus fulgidus. Four invariant amino acids in the central portion of H7 (Tyr(682) and Asn(683)) and H8 (Met(711) and Ser(715)) were identified as required for Cu(+) binding. Replacement of these residues abolished enzyme activity. These proteins did not undergo Cu(+)-dependent phosphorylation by ATP but were phosphorylated by P(i) in the absence of Cu(+). Moreover, the presence of Cu(+) could not prevent the enzyme phosphorylation by P(i). Other conserved residues in the H7-H8 region were not required for metal binding. Mutation of two invariant Pro residues had little effect on enzyme function. Replacement of residues located close to the cytoplasmic end of H7-H8 led to inactive enzymes. However, these were able to interact with Cu(+) and undergo phosphorylation. This suggests that the integrity of this region is necessary for conformational transitions but not for ligand binding. These data support the presence of a unique transmembrane Cu(+) binding/translocation site constituted by Tyr-Asn in H7, Met and Ser in H8, and two Cys in H6 of Cu(+)-ATPases. The likely Cu(+) coordination during transport appears distinct from that observed in Cu(+) chaperone proteins or catalytic/redox metal binding sites.
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Affiliation(s)
- Atin K Mandal
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA
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170
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Anastassopoulou I, Banci L, Bertini I, Cantini F, Katsari E, Rosato A. Solution Structure of the Apo and Copper(I)-Loaded Human Metallochaperone HAH1†. Biochemistry 2004; 43:13046-53. [PMID: 15476398 DOI: 10.1021/bi0487591] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The human metallochaperone HAH1 has been produced in Escherichia coli with four additional amino acids at the C-terminus and characterized in solution by NMR spectroscopy, both with and without copper(I). The solution structure of the apo-HAH1 monomer has a root-mean-square-deviation (RMSD) of 0.50 A for the coordinates of the backbone atoms and 0.96 A for all heavy atoms. These values compare, respectively, with 0.45 and 0.95 A for copper(I)-HAH1. There are only minor structural rearrangements upon copper(I) binding. In particular, the variation of interatomic interactions around the metal-binding region is limited to a movement of Lys60 toward the metal site. The protein structures are similar to those obtained by X-ray crystallography in a variety of derivatives, with backbone RMSD values below 1 A. In the holoprotein, copper(I) is confirmed to be two coordinated. If these data are compared with those of orthologue proteins, we learn that HAH1 has a lower tendency to change coordination number from two to three. Such a switch in coordination is a key step in copper transfer.
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Affiliation(s)
- Ioanna Anastassopoulou
- Institute of Physical Chemistry, NCSR Demokritos, 153 10 Aghia Paraskevi Attikis, Greece
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171
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van Dongen EMWM, Klomp LWJ, Merkx M. Copper-dependent protein–protein interactions studied by yeast two-hybrid analysis. Biochem Biophys Res Commun 2004; 323:789-95. [PMID: 15381069 DOI: 10.1016/j.bbrc.2004.08.160] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Indexed: 11/21/2022]
Abstract
An important step in copper homeostasis is delivery of copper to a specific P-type ATPase in the Golgi apparatus (Ccc2 in yeast, ATP7A and ATP7B in humans) by a small copper chaperone protein (Atx1 in yeast, ATOX1 in humans). Atx1 and ATOX1 both contain an MXCXXC motif that is also present in Ccc2 (two motifs) and ATP7A/B (six motifs). Protein-protein interactions probably require coordination of one Cu(I) by cysteines from both MXCXXC motifs. We applied yeast two-hybrid analysis to screen systematically all possible interactions between MXCXXC-containing domains in these proteins. We demonstrate that ATOX1 and Atx1 preferentially interact with domains 2 and 4 of ATP7B and that Atx1 interacts with both Ccc2 domains. All combinations show a remarkable bell-shaped dependency on copper concentration that is maximal just below normal copper levels. Our results suggest that yeast two-hybrid analysis can be used to study the intracellular copper status of a cell.
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Affiliation(s)
- Elisabeth M W M van Dongen
- Laboratory of Macromolecular and Organic Chemistry, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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172
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Abstract
The solution structure of Sco1 from Bacillus subtilis is the first structure of a protein important in the assembly of cytochrome c oxidase (CcO). The assembly of CcO requires the insertion of multiple cofactors. Sco1 is a conserved protein implicated in formation of the binuclear Cu(A) center.
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Affiliation(s)
- Dennis R Winge
- Departments of Biochemistry and Medicine, University of Utah Health Sciences Center, Salt Lake City, UT 8413, USA
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173
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Bertini I, Rosato A. A Genomic Frontier in Bioinorganic Chemistry. CHEM LETT 2004. [DOI: 10.1246/cl.2004.946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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174
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Jones CE, Daly NL, Cobine PA, Craik DJ, Dameron CT. Structure and metal binding studies of the second copper binding domain of the Menkes ATPase. J Struct Biol 2004; 143:209-18. [PMID: 14572476 DOI: 10.1016/j.jsb.2003.08.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Biological utilisation of copper requires that the metal, in its ionic forms, be meticulously transported, inserted into enzymes and regulatory proteins, and excess be excreted. To understand the trafficking process, it is crucial that the structures of the proteins involved in the varied processes be resolved. To investigate copper binding to a family of structurally related copper-binding proteins, we have characterised the second Menkes N-terminal domain (MNKr2). The structure, determined using 1H and 15N heteronuclear NMR, of the reduced form of MNKr2 has revealed two alpha-helices lying over a single beta-sheet and shows that the binding site, a Cys(X)2Cys pair, is located on an exposed loop. 1H-15N HSQC experiments demonstrate that binding of Cu(I) causes changes that are localised to conserved residues adjacent to the metal binding site. Residues in this area are important to the delivery of copper by the structurally related Cu(I) chaperones. Complementary site-directed mutagenesis of the adjacent residues has been used to probe the structural roles of conserved residues.
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Affiliation(s)
- Christopher E Jones
- The National Research Centre for Environmental Toxicology, The University of Queensland, 39 Kessels Road, Coopers Plains, Qld 4108, Australia
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175
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Banci L, Bertini I, Ciofi-Baffoni S, Su XC, Borrelly GPM, Robinson NJ. Solution Structures of a Cyanobacterial Metallochaperone. J Biol Chem 2004; 279:27502-10. [PMID: 15075318 DOI: 10.1074/jbc.m402005200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Atx1 copper metallochaperone from Synechocystis PCC 6803, ScAtx1, interacts with two P(1)-type copper ATPases to supply copper proteins within intracellular compartments, avoiding ATPases for other metals en route. Here we report NMR-derived solution structures for ScAtx1. The monomeric apo form has a betaalphabetabetaalpha fold with backbone motions largely restricted to loop 1 containing Cys-12 and Cys-15. The tumbling rate of Cu(I)ScAtx1 (0.1-0.8 mm) implies dimers. Experimental restraints are satisfied by symmetrical dimers with Cys-12 or His-61, but not Cys-15, invading the copper site of the opposing subunit. A full sequence of copper ligands from the cell surface to thylakoid compartments is proposed, considering in vitro homodimer liganding to mimic in vivo liganding in ScAtx1-ATPase heterodimers. A monomeric high resolution structure for Cu(I)ScAtx1, with Cys-12, Cys-15, and His-61 as ligands, is calculated without violations despite the rotational correlation time. (2)J(NH) couplings in the imidazole ring of His-61 establish coordination of N(epsilon2) to copper. His-61 is analogous to Lys-65 in eukaryotic metallochaperones, stabilizing Cu(I)S(2) complexes but by binding Cu(I) rather than compensating charge. Cys-Cys-His ligand sets are an emergent theme in some copper metallochaperones, although not in related Atx1, CopZ, or Hah1. Surface charge (Glu-13) close to the metal-binding site of ScAtx1 is likely to support interaction with complementary surfaces of copper-transporting ATPases (PacS-Arg-11 and CtaA-Lys-14) but to discourage interaction with zinc ATPase ZiaA and so inhibit aberrant formation of copper-ZiaA complexes.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
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176
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Abstract
Copper is an essential cofactor for approximately a dozen cuproenzymes in which copper is bound to specific amino acid residues in an active site. However, free cuprous ions react readily with hydrogen peroxide to yield the deleterious hydroxyl radical. Therefore, copper homeostasis is regulated very tightly, and unbound copper is extremely low in concentration. Copper imported by the plasma membrane transport protein Ctr1 rapidly binds to intracellular copper chaperone proteins. Atox1 delivers copper to the secretory pathway and docks with either copper-transporting ATPase ATP7B in the liver or ATP7A in other cells. ATP7B directs copper to plasma ceruloplasmin or to biliary excretion in concert with a newly discovered chaperone, Murr1, the protein missing in canine copper toxicosis. ATP7A directs copper within the transgolgi network to the proteins dopamine beta-monooxgenase, peptidylglycine alpha-amidating monooxygenase, lysyl oxidase, and tyrosinase, depending on the cell type. CCS is the copper chaperone for Cu,Zn-superoxide dismutase; it delivers copper in the cytoplasm and intermitochondrial space. Cox17 delivers copper to mitochondria to cytochrome c oxidase via the chaperones Cox11, Sco1, and Sco2. Other copper chaperones may exist and might include metallothionein and amyloid precursor protein (APP). Genetic and nutritional studies have illustrated the essential nature of these copper-binding proteins; alterations in their levels are associated with severe pathology.
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Affiliation(s)
- Joseph R Prohaska
- Department of Biochemistry and Molecular Biology, University of Minnesota, Duluth, 55812, USA.
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177
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Serre L, Rossy E, Pebay-Peyroula E, Cohen-Addad C, Covès J. Crystal Structure of the Oxidized Form of the Periplasmic Mercury-binding Protein MerP from Ralstonia metallidurans CH34. J Mol Biol 2004; 339:161-71. [PMID: 15123428 DOI: 10.1016/j.jmb.2004.03.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2003] [Revised: 01/23/2004] [Accepted: 03/12/2004] [Indexed: 11/27/2022]
Abstract
In Ralstonia metallidurans CH34, the gene merP encodes for a periplasmic mercury-binding protein which is capable of binding one mercury atom. The metal-binding site of MerP consists of the highly conserved sequence GMTCXXC found in the family that includes metallochaperones and metal-transporting ATPases. We purified MerP from R.metallidurans CH34 and solved its crystal structure under the oxidized form at 2.0A resolution. Superposition with structures of other metal-binding proteins shows that the global structure of R.metallidurans CH34 oxidized MerP follows the general topology of the whole family. The largest differences are observed with the NMR structure of oxidized Shigella flexneri MerP. Detailed analysis of the metal-binding site suggests a direct role for Y66 in stabilizing the thiolate group of C17 during the mercury-binding reaction. The metal-binding site of oxidized MerP is also similar to the metal-binding sites of oxidized copper chaperone for superoxide dismutase and Atx1, two copper-binding proteins from Saccharomyces cerevisiae. Finally, the packing of the MerP crystals suggests that F38, a well-conserved residue in the MerP family may be important in mercury binding and transfer. We propose a possible mechanism of mercury transfer between two CXXC motifs based on a transient bi-coordinated mercury intermediate.
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Affiliation(s)
- Laurence Serre
- Institut de Biologie Structurale, UMR 5075-CNRS-CEA-UJF/ IBS-LPM, 41 Avenue Jules Horowitz, 38027 Grenoble Cedex 01, France.
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178
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Arnesano F, Banci L, Bertini I, Ciofi‐Baffoni S. Perspectives in Inorganic Structural Genomics: A Trafficking Route for Copper. Eur J Inorg Chem 2004. [DOI: 10.1002/ejic.200300841] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Fabio Arnesano
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy, Fax: (internat.) + 39‐055‐4574271
| | - Lucia Banci
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy, Fax: (internat.) + 39‐055‐4574271
| | - Ivano Bertini
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy, Fax: (internat.) + 39‐055‐4574271
| | - Simone Ciofi‐Baffoni
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy, Fax: (internat.) + 39‐055‐4574271
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179
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Arnesano F, Banci L, Bertini I, Bonvin AMJJ. A Docking Approach to the Study of Copper Trafficking Proteins. Structure 2004; 12:669-76. [PMID: 15062089 DOI: 10.1016/j.str.2004.03.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Revised: 01/15/2004] [Accepted: 01/20/2004] [Indexed: 10/26/2022]
Abstract
A structural model of the transient complex between the yeast copper chaperone Atx1 and the first soluble domain of the copper transporting ATPase Ccc2 was obtained with HADDOCK, combining NMR chemical shift mapping information with in silico docking. These two proteins are involved in copper trafficking in yeast cells. Calculations were performed starting with the copper ion either bound to Atx1 or to Ccc2 and using the experimental structures of the copper-loaded and apo forms of each protein. The copper binding motifs of the two proteins are found in close proximity. Copper tends to move from Atx1 to Ccc2, consistent with the physiological direction of transfer, with concomitant structural rearrangements, in agreement with experimental observations. The interaction is mainly of an electrostatic nature with hydrogen bonds stabilizing the complex. The structural data are relevant for a number of proteins homologous to Atx1 and Ccc2 and conserved from bacteria to humans.
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Affiliation(s)
- Fabio Arnesano
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
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180
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Narindrasorasak S, Yao P, Sarkar B. Protein disulfide isomerase, a multifunctional protein chaperone, shows copper-binding activity. Biochem Biophys Res Commun 2004; 311:405-14. [PMID: 14592429 DOI: 10.1016/j.bbrc.2003.09.226] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Protein disulfide isomerase (PDI) is a 55 kDa multifunctional protein of the endoplasmic reticulum (ER) involved in protein folding and isomerization. In addition to the chaperone and catalytic functions, PDI is a major calcium-binding protein of the ER. Although the active site of PDI has a similar motif CXXC to the Cu-binding motif in Wilson and Menkes proteins and in other copper chaperones, there has been no report on any metal-binding capability of PDI other than calcium binding. We present evidence that PDI is a copper-binding protein. In the absence of reducing agent freshly reduced PDI can bind a maximum of 4 mol of Cu(II) and convert to Cu(I). These bound Cu(I) are surface exposed as they can be competed readily by BCS reagent, a Cu(I) specific chelator. However, when the binding is performed using the mixture of Cu(II) and 1mM DTT, the total number of Cu(I) bound increases to 10 mol/mol, and it is slower to react with BCS, indicating a more protected environment. In both cases, the copper-bound forms of PDI exist as tetramers while apo-protein is a monomer. These findings suggest that PDI plays a role in intracellular copper disposition.
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Affiliation(s)
- Suree Narindrasorasak
- Department of Structural Biology and Biochemistry, The Research Institute of the Hospital for Sick Children, Toronto, Ont., Canada M5G 1X8
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181
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Walker JM, Huster D, Ralle M, Morgan CT, Blackburn NJ, Lutsenko S. The N-terminal metal-binding site 2 of the Wilson's Disease Protein plays a key role in the transfer of copper from Atox1. J Biol Chem 2004; 279:15376-84. [PMID: 14754885 DOI: 10.1074/jbc.m400053200] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Wilson's disease protein (WNDP) is a copper-transporting ATPase regulating distribution of copper in the liver. Mutations in WNDP lead to a severe metabolic disorder, Wilson's disease. The function of WNDP depends on Atox1, a cytosolic metallochaperone that delivers copper to WNDP. We demonstrate that the metal-binding site 2 (MBS2) in the N-terminal domain of WNDP (N-WNDP) plays an important role in this process. The transfer of one copper from Atox1 to N-WNDP results in selective protection of the metal-coordinating cysteines in MBS2 against labeling with a cysteine-directed probe. Such selectivity is not observed when free copper is added to N-WNDP. Similarly, site-directed mutagenesis of MBS2 eliminates stimulation of the catalytic activity of WNDP by the copper-Atox1 complex but not by free copper. The Atox1 preference toward MBS2 is likely due to specific protein-protein interactions and is not due to unique surface exposure of the metal-coordinating residues or higher copper binding affinity of MBS2 compared with other sites. Competition experiments using a copper chelator revealed that MBS2 retained copper much better than Atox1, and this may facilitate the metal transfer process. X-ray absorption spectroscopy of the isolated recombinant MBS2 demonstrated that this sub-domain coordinates copper with a linear biscysteinate geometry, very similar to that of Atox1. Therefore, non-coordinating residues in the vicinity of the metal-binding sites are responsible for the difference in the copper binding properties of MBS2 and Atox1. The intramolecular changes that accompany transfer of a single copper to N-WNDP are discussed.
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Affiliation(s)
- Joel M Walker
- Department of Biochemistry and Molecular Biology, Biomolecular Systems, Oregon Health and Science University, Portland, Oregon 97239-3098, USA
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182
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Sénèque O, Crouzy S, Boturyn D, Dumy P, Ferrand M, Delangle P. Novel model peptide for Atx1-like metallochaperones. Chem Commun (Camb) 2004:770-1. [PMID: 15045055 DOI: 10.1039/b315489k] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The novel cyclodecapeptide c(GMTCSGCSRP) is able to bind soft metals with a selectivity for Hg(2+) and Cu(+) over Pb(2+), Cd(2+) and Zn(2+), and is demonstrated to be an excellent structural model of the binding loop of the copper metallochaperone Atx1 in its apo and mercury loaded forms.
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Affiliation(s)
- Olivier Sénèque
- Laboratoire de Reconnaissance Ionique, SCIB, CEA/DSM/DRFMC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
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183
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Banci L, Bertini I, Ciofi-Baffoni S, Gonnelli L, Su XC. Structural Basis for the Function of the N-terminal Domain of the ATPase CopA from Bacillus subtilis. J Biol Chem 2003; 278:50506-13. [PMID: 14514665 DOI: 10.1074/jbc.m307389200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The solution structure of the N-terminal region (151 amino acids) of a copper ATPase, CopA, from Bacillus subtilis, is reported here. It consists of two domains, CopAa and CopAb, linked by two amino acids. It is found that the two domains, which had already been separately characterized, interact one to the other through a hydrogen bond network and a few hydrophobic interactions, forming a single rigid body. The two metal binding sites are far from one another, and the short link between the domains prevents them from interacting. This and the surface electrostatic potential suggest that each domain receives copper from the copper chaperone, CopZ, independently and transfers it to the membrane binding site of CopA. The affinity constants of silver(I) and copper(I) are similar for the two sites as monitored by NMR. Because the present construct "domain-short link-domain" is shared also by the last two domains of the eukaryotic copper ATPases and several residues at the interface between the two domains are conserved, the conclusions of the present study have general validity for the understanding of the function of copper ATPases.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
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184
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Rossy E, Champier L, Bersch B, Brutscher B, Blackledge M, Covès J. Biophysical characterization of the MerP-like amino-terminal extension of the mercuric reductase from Ralstonia metallidurans CH34. J Biol Inorg Chem 2003; 9:49-58. [PMID: 14624351 DOI: 10.1007/s00775-003-0495-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Accepted: 09/26/2003] [Indexed: 10/26/2022]
Abstract
The purified native mercuric reductase (MerA) from Ralstonia metallidurans CH34 contains an N-terminal sequence of 68 amino acids predicted to be homologous to MerP, the periplasmic mercury-binding protein. This MerP-like protein has now been expressed independently. The protein was named MerAa by homology with Ccc2a, the first soluble domain of the copper-transporting ATPase from yeast. Deltaa has been characterized using a set of biophysical techniques. The binding of mercury was followed using circular dichroism spectroscopy and electrospray mass spectrometry. The two cysteine residues contained in the consensus sequence GMTC XXC are involved in the binding of one mercury atom, with an apparent affinity comparable to that of MerP for the same metal. The metal-binding site is confirmed by NMR chemical shift changes observed between apo- and metal-bound MerAa in solution. NMR shift and NOE data also indicate that only minor structural changes occur upon metal binding. Further NMR investigation of the fold of MerAa using long-range methyl-methyl NOE and backbone residual dipolar coupling data confirm the expected close structural homology with MerP. (15)N relaxation data show that MerAa is a globally rigid molecule. An increased backbone mobility was observed for the loop region connecting the first beta-strand and the first alpha-helix and comprising the metal-binding domain. Although significantly reduced, this loop region keeps some conformational flexibility upon metal binding. Altogether, our data suggest a role of MerAa in mercury trafficking.
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Affiliation(s)
- Emmanuel Rossy
- Laboratoire de Chimie et Biochimie des Centres Redox Biologiques, CEA-Grenoble, DRDC/CB, UMR 5047 CNRS - CEA, Université Joseph Fourier, 17 Avenue des Martyrs, 38054 Cedex 9, Grenoble, France
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185
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Arnesano F, Banci L, Benvenuti M, Bertini I, Calderone V, Mangani S, Viezzoli MS. The evolutionarily conserved trimeric structure of CutA1 proteins suggests a role in signal transduction. J Biol Chem 2003; 278:45999-6006. [PMID: 12949080 DOI: 10.1074/jbc.m304398200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CutA1 are a protein family present in bacteria, plants, and animals, including humans. Escherichia coli CutA1 is involved in copper tolerance, whereas mammalian proteins are implicated in the anchoring of acetylcholinesterase in neuronal cell membranes. The x-ray structures of CutA1 from E. coli and rat were determined. Both proteins are trimeric in the crystals and in solution through an inter-subunit beta-sheet formation. Each subunit consists of a ferredoxin-like (beta1alpha1beta2beta3alpha2beta4) fold with an additional strand (beta5), a C-terminal helix (alpha3), and an unusual extended beta-hairpin involving strands beta2 and beta3. The bacterial CutA1 is able to bind copper(II) in vitro through His2Cys coordination in a type II water-accessible site, whereas the rat protein precipitates in the presence of copper(II). The evolutionarily conserved trimeric assembly of CutA1 is reminiscent of the architecture of PII signal transduction proteins. This similarity suggests an intriguing role of CutA1 proteins in signal transduction through allosteric communications between subunits.
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Affiliation(s)
- Fabio Arnesano
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
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186
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Mana-Capelli S, Mandal AK, Argüello JM. Archaeoglobus fulgidus CopB is a thermophilic Cu2+-ATPase: functional role of its histidine-rich-N-terminal metal binding domain. J Biol Chem 2003; 278:40534-41. [PMID: 12876283 DOI: 10.1074/jbc.m306907200] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
P1B-type ATPases transport heavy metal ions across cellular membranes. Archaeoglobus fulgidus CopB is a member of this subfamily. We have cloned, expressed in Escherichia coli, and functionally characterized this enzyme. CopB and its homologs are distinguished by a metal binding sequence Cys-Pro-His in their sixth transmembrane segment (H6) and a His-rich N-terminal metal binding domain (His-N-MBD). CopB is a thermophilic protein active at 75 degrees C and high ionic strength. It is activated by Cu2+ with high apparent affinity (K1/2 = 0.28 microm) and partially by Cu+ and Ag+ (22 and 55%, respectively). The higher turnover was associated with a faster phosphorylation rate in the presence of Cu2+. A truncated CopB lacking the first 54 amino acids was constructed to characterize the His-N-MBD. This enzyme showed reduced ATPase activity (50% of wild type) but no changes in metal selectivity, ATP dependence, or phosphorylation levels. However, a slower rate of dephosphorylation of the E2P(Cu2+) form was observed for truncated CopB. The data suggest that the presence of the His residue in the putative transmembrane metal binding site of CopB determines a selectivity for this enzyme that is different for that observed in Cu+/Ag+-ATPases carrying a Cys-Pro-Cys sequence. The His-NMBD appears to have a regulatory role affecting the metal transport rate by controlling the metal release/dephosphorylation rates.
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Affiliation(s)
- Sebasián Mana-Capelli
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA
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187
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Roy A, Solodovnikova N, Nicholson T, Antholine W, Walden WE. A novel eukaryotic factor for cytosolic Fe-S cluster assembly. EMBO J 2003; 22:4826-35. [PMID: 12970194 PMCID: PMC212722 DOI: 10.1093/emboj/cdg455] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2003] [Revised: 07/21/2003] [Accepted: 07/22/2003] [Indexed: 11/14/2022] Open
Abstract
Iron regulatory protein 1 (IRP1) is regulated through the assembly/disassembly of a [4Fe-4S] cluster, which interconverts IRP1 with cytosolic aconitase. A genetic screen to isolate Saccharomyces cerevisiae strains bearing mutations in genes required for the conversion of IRP1 to c-aconitase led to the identification of a previously uncharacterized, essential gene, which we call CFD1 (cytosolic Fe-S cluster deficient). CFD1 encodes a highly conserved, putative P-loop ATPase. A non-lethal mutation of CFD1 (cfd1-1) reduced c-aconitase specific activity in IRP1-transformed yeast by >90%, although IRP1 in these cells could be readily converted to c-aconitase in vitro upon incubation with iron alone. IRP1-transformed cfd1-1 yeast lacked EPR-detectable Fe-S clusters in c-aconitase, pointing to a defect in Fe-S cluster assembly. The specific activity of another cytosolic Fe-S protein, Leu1p, was also inhibited by >90% in cfd1-1 yeast, whereas activity of mitochondrial Fe-S proteins was not inhibited. Consistent with a cytosolic site of activity, Cfd1p was localized in the cytoplasm. To our knowledge, Cfd1p is the first cytoplasmic Fe-S cluster assembly factor described in eukaryotes.
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Affiliation(s)
- Amit Roy
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL 60612, USA
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188
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Roberts SA, Wildner GF, Grass G, Weichsel A, Ambrus A, Rensing C, Montfort WR. A labile regulatory copper ion lies near the T1 copper site in the multicopper oxidase CueO. J Biol Chem 2003; 278:31958-63. [PMID: 12794077 DOI: 10.1074/jbc.m302963200] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
CueO, a multicopper oxidase, is part of the copper-regulatory cue operon in Escherichia coli, is expressed under conditions of copper stress and shows enhanced oxidase activity when additional copper is present. The 1.7-A resolution structure of a crystal soaked in CuCl2 reveals a Cu(II) ion bound to the protein 7.5 A from the T1 copper site in a region rich in methionine residues. The trigonal bipyramidal coordination sphere is unusual, containing two methionine sulfur atoms, two aspartate carboxylate oxygen atoms, and a water molecule. Asp-439 both ligates the labile copper and hydrogen-bonds to His-443, which ligates the T1 copper. This arrangement may mediate electron transfer from substrates to the T1 copper. Mutation of residues bound to the labile copper results in loss of oxidase activity and of copper tolerance, confirming a regulatory role for this site. The methionine-rich portion of the protein, which is similar to that of other proteins involved in copper homeostasis, does not display additional copper binding. The type 3 copper atoms of the trinuclear cluster in the structure are bridged by a chloride ion that completes a square planar coordination sphere for the T2 copper atom but does not affect oxidase activity.
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Affiliation(s)
- Sue A Roberts
- Departments of Biochemistry and Molecular Biophysics and Soil, Water, and Environmental Science, University of Arizona, Tucson, Arizona 85721
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189
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Banci L, Bertini I, Ciofi-Baffoni S, Gonnelli L, Su XC. A core mutation affecting the folding properties of a soluble domain of the ATPase protein CopA from Bacillus subtilis. J Mol Biol 2003; 331:473-84. [PMID: 12888353 DOI: 10.1016/s0022-2836(03)00769-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The two N-terminal domains of the P-type copper ATPase, CopAa and CopAb, from Bacillus subtilis differ in their folding capabilities in vitro. Whereas CopAb has the typical betaalphabetabetaalphabeta structure and is a rigid protein, CopAa is found to be largely unfolded. A sequence analysis of the two and of orthologue homologous proteins indicates that Ser46 in CopAa may destabilise the hydrophobic core, as also confirmed through a bioinformatic energy study. CopAb has a Val in the corresponding position. The S46V and S46A mutants are found to be folded, although the latter displays multiple conformations. S46VCopAa, in both apo and copper(I) loaded forms, has very similar structural and dynamic properties with respect to CopAb, besides a different length of strand beta2 and beta4. It is intriguing that the oxygen of Thr16 is found close, though at longer than bonding distance, to copper in both domains, as it also occurs in a human orthologue domain. This study contributes to understanding the behaviour of proteins that do not properly fold in vitro. A possible biological significance of the peculiar folding behaviour of this domain is discussed.
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Affiliation(s)
- Lucia Banci
- Department of Chemistry, The Magnetic Resonance Center CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
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190
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Stoyanov JV, Magnani D, Solioz M. Measurement of cytoplasmic copper, silver, and gold with a lux biosensor shows copper and silver, but not gold, efflux by the CopA ATPase of Escherichia coli. FEBS Lett 2003; 546:391-4. [PMID: 12832075 DOI: 10.1016/s0014-5793(03)00640-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Copper, silver, gold and other heavy metals are potentially toxic to cells. Copper is also essential and cellular levels must be carefully controlled. In contrast, there is no known biological role for silver or gold and they have not been recognized as metals that are under homeostatic control. Using a luminescent biosensor based of the Vibrio fischeri lux gene cluster under the control of the Escherichia coli copA promoter/CueR metal-responsive regulator, we could show that in E. coli, cytoplasmic copper and silver, but not gold, are regulated by the CopA ATPase, the major copper efflux pump.
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Affiliation(s)
- Jivko V Stoyanov
- Department of Clinical Pharmacology, University of Berne, Murtenstrasse 35, 3010 Berne, Switzerland
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191
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Ralle M, Lutsenko S, Blackburn NJ. X-ray absorption spectroscopy of the copper chaperone HAH1 reveals a linear two-coordinate Cu(I) center capable of adduct formation with exogenous thiols and phosphines. J Biol Chem 2003; 278:23163-70. [PMID: 12686548 DOI: 10.1074/jbc.m303474200] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The human copper chaperone HAH1 transports copper to the Menkes and Wilson proteins, which are copper-translocating P-type ATPases located in the trans-Golgi apparatus and believed to provide copper for important enzymes such as ceruloplasmin, tyrosinase, and peptidylglycine monooxygenase. Although a substantial amount of structural data exist for HAH1 and its yeast and bacterial homologues, details of the copper coordination remain unclear and suggest the presence of two protein-derived cysteine ligands and a third exogenous thiol ligand. Here we report the preparation and reconstitution of HAH1 with Cu(I) using a protocol that minimizes the use of thiol reagents believed to be the source of the third ligand. We show by x-ray absorption spectroscopy that this reconstitution protocol generates an occupied Cu(I) binding site with linear biscysteinate coordination geometry, as evidenced by (i) an intense edge absorption centered at 8982.5 eV, with energy and intensity identical to the rigorously linear two-coordinate model complex bis-2,3,5,6-tetramethylbenzene thiolate Cu(I) and (ii) an EXAFS spectrum that could be fit to two Cu-S interactions at 2.16 A, a distance typical of digonal Cu(I) coordination. Binding of exogenous ligands (GSH, dithiothreitol, and tris-(2-carboxyethyl)-phosphine) to the Cu(I) was investigated. When GSH or dithiothreitol was added to the chaperone during the reconstitution procedure, the resulting Cu(I)- HAH1 remained two-coordinate, whereas the addition of the phosphine during reconstitution elicited a three-coordinate species. When the exogenous ligands were titrated into the Cu(I)-HAH1, all formed three-coordinate adducts but with differing affinities. Thus, GSH and dithiothreitol showed weaker binding, with estimated KD values in the range 10-25 mm, whereas tris-(2-carboxyethyl)-phosphine showed stronger affinity, with a KD value of <5 mm. The implications of these findings for mechanisms of copper transport are discussed.
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Affiliation(s)
- Martina Ralle
- Department of Environmental and Biomolecular Systems, OGI School of Science & Engineering, Oregon Health & Science University, Beaverton, Oregon 97006-8921, USA
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192
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Finney LA, O'Halloran TV. Transition metal speciation in the cell: insights from the chemistry of metal ion receptors. Science 2003; 300:931-6. [PMID: 12738850 DOI: 10.1126/science.1085049] [Citation(s) in RCA: 793] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The essential transition metal ions are avidly accumulated by cells, yet they have two faces: They are put to use as required cofactors, but they also can catalyze cytotoxic reactions. Several families of proteins are emerging that control the activity of intracellular metal ions and help confine them to vital roles. These include integral transmembrane transporters, metalloregulatory sensors, and diffusible cytoplasmic metallochaperone proteins that protect and guide metal ions to targets. It is becoming clear that many of these proteins use atypical coordination chemistry to accomplish their unique goals. The different coordination numbers, types of coordinating residues, and solvent accessibilities of these sites are providing insight into the inorganic chemistry of the cytoplasm.
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Affiliation(s)
- Lydia A Finney
- Department of Chemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208-3113, USA
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193
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Banci L, Pierattelli R, Vila AJ. Nuclear magnetic resonance spectroscopy studies on copper proteins. ADVANCES IN PROTEIN CHEMISTRY 2003; 60:397-449. [PMID: 12418182 DOI: 10.1016/s0065-3233(02)60058-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- Lucia Banci
- CERM, University of Florence, 50019 Sesto Fiorentino, Italy
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194
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Abstract
Genome sequencing has revolutionized all fields of life sciences. Bioinorganic chemistry is certainly not immune to this influence, which is presenting unprecedented challenges. A new goal for bioinorganic chemistry is the investigation of the linkages between inorganic elements and genomic information. This requires new advancements andor the development of new expertise in fields such as bioinformatics and genetics but also provides a driving force to push forward the exploitation of traditional analytical techniques and spectroscopic tools. The "case study" of metal homeostasis in cells is discussed to provide a flavor of the current evolution of the field.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy.
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195
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Liu PC, Koeller DM, Kaler SG. Genomic organization of ATOX1, a human copper chaperone. BMC Genet 2003; 4:4. [PMID: 12594858 PMCID: PMC150598 DOI: 10.1186/1471-2156-4-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2002] [Accepted: 02/05/2003] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Copper is an essential trace element that plays a critical role in the survival of all living organisms. Menkes disease and occipital horn syndrome (OHS) are allelic disorders of copper transport caused by defects in a X-linked gene (ATP7A) that encodes a P-type ATPase that transports copper across cellular membranes, including the trans-Golgi network. Genetic studies in yeast recently revealed a new family of cytoplasmic proteins called copper chaperones which bind copper ions and deliver them to specific cellular pathways. Biochemical studies of the human homolog of one copper chaperone, ATOX1, indicate direct interaction with the Menkes/OHS protein. Although no disease-associated mutations have been reported in ATOX1, mice with disruption of the ATOX1 locus demonstrate perinatal mortality similar to that observed in the brindled mice (Mobr), a mouse model of Menkes disease. The cDNA sequence for ATOX1 is known, and the genomic organization has not been reported. RESULTS We determined the genomic structure of ATOX1. The gene contains 4 exons spanning a genomic distance of approximately 16 kb. The translation start codon is located in the 3' end of exon 1 and the termination codon in exon 3. We developed a PCR-based assay to amplify the coding regions and splice junctions from genomic DNA. We screened for ATOX1 mutations in two patients with classical Menkes disease phenotypes and one individual with occipital horn syndrome who had no alterations detected in ATP7A, as well as an adult female with chronic anemia, low serum copper and evidence of mild dopamine-beta-hydroxylase deficiency and no alterations in the ATOX1 coding or splice junction sequences were found. CONCLUSIONS In this study, we characterized the genomic structure of the human copper chaperone ATOX1 to facilitate screening of this gene from genomic DNA in patients whose clinical or biochemical phenotypes suggest impaired copper transport.
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Affiliation(s)
- Po-Ching Liu
- Unit on Pediatric Genetics, Laboratory of Clinical Genomics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - David M Koeller
- Department of Pediatrics, Oregon Health Sciences University, Portland, OR, USA
| | - Stephen G Kaler
- Unit on Pediatric Genetics, Laboratory of Clinical Genomics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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196
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Urvoas A, Amekraz B, Moulin C, Le Clainche L, Stöcklin R, Moutiez M. Analysis of the metal-binding selectivity of the metallochaperone CopZ from Enterococcus hirae by electrospray ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2003; 17:1889-1896. [PMID: 12876690 DOI: 10.1002/rcm.1130] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Metallochaperones are soluble proteins involved in metal transport and regulation in vivo. Copper metallochaperones belong to a structural family of metal binding domains displaying a ferredoxin-like fold (betaalphabetabetaalphabeta) and a consensus metal-binding motif MXCXXC. The metal-binding selectivities for this class of proteins are poorly documented so far. The present study focuses on the measurement of the selectivity of the copper metallochaperone CopZ from Enterococcus hirae for different metal ions using an experimental approach based on electrospray ionization mass spectrometry (ESI-MS). All the metal cations tested, i.e. Cu(I), Cu(II), Hg(II), Cd(II) and Co(II), form specific metal complexes with CopZ. The study of a chemically modified CopZ as well as variants of CopZ in the active site demonstrated that the complexes observed by ESI-MS, i.e. in the gas phase, corresponded to the complexes previously observed by other analytical methods in solution. Competition experiments allowed the classification of the metal ions by increasing affinities for CopZ as follows: Co << Cd < Hg < Cu. A dissociation constant in the range of 20 microM was determined for cobalt. The affinity of CopZ for the other metals tested was found to be higher, with dissociation constants smaller than micromolar.
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Affiliation(s)
- Agathe Urvoas
- CEA, Département d'Ingénierie et d'Etudes des Protéines--Bâtiment 152, C.E. Saclay, F-91191 Gif-sur-Yvette, France
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197
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Banci L, Bertini I, Ciofi-Baffoni S, Finney LA, Outten CE, O'Halloran TV. A new zinc-protein coordination site in intracellular metal trafficking: solution structure of the Apo and Zn(II) forms of ZntA(46-118). J Mol Biol 2002; 323:883-97. [PMID: 12417201 DOI: 10.1016/s0022-2836(02)01007-0] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Zinc, a metal ion that functions in a wide variety of catalytic and structural sites in metalloproteins, is shown here to adopt a novel coordination environment in the Escherichia coli transport protein ZntA. The ZntA protein is a P-type ATPase that pumps zinc out of the cytoplasm and into the periplasm. It is physiologically selective for Zn(II) and functions with metalloregulatory proteins in the cell to keep the zinc quota within strict limits. Yet, the N-terminal cytoplasmic domain contains a region that is highly homologous to the yeast Cu(I) metallochaperone Atx1. To investigate how the structure of this region may influence its function, this fragment, containing residues 46-118, has been cloned out of the gene and overexpressed. We report here the solution structure of this fragment as determined by NMR. Both the apo and Zn(II)-ZntA(46-118) structures have been determined. It contains a previously unknown protein coordination site for zinc that includes two cysteine residues, Cys59 and Cys62, and a carboxylate residue, Asp58. The solvent accessibility of this site is also remarkably high, a feature that increasingly appears to be a characteristic of domains of heavy metal ion transport proteins. The participation of Asp58 in this ZntA metal ion binding site may play an important role in modulating the relative affinities and metal exchange rates for Zn(II)/Pb(II)/Cd(II) as compared with other P-type ATPases, which are selective for Cu(I) or Ag(I).
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
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198
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Lutsenko S, Efremov RG, Tsivkovskii R, Walker JM. Human copper-transporting ATPase ATP7B (the Wilson's disease protein): biochemical properties and regulation. J Bioenerg Biomembr 2002; 34:351-62. [PMID: 12539962 DOI: 10.1023/a:1021297919034] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Wilson's disease protein (WNDP) is a product of a gene ATP7B that is mutated in patients with Wilson's disease, a severe genetic disorder with hepatic and neurological manifestations caused by accumulation of copper in the liver and brain. In a cell, WNDP transports copper across various cell membranes using energy of ATP-hydrolysis. Copper regulates WNDP at several levels, modulating its catalytic activity, posttranslational modification, and intracellular localization. This review summarizes recent studies on enzymatic function and copper-dependent regulation of WNDP. Specifically, we describe the molecular architecture and major biochemical properties of WNDP, discuss advantages of the recently developed functional expression of WNDP in insect cells, and summarize the results of the ligand-binding studies and molecular modeling experiments for the ATP-binding domain of WNDP. In addition, we speculate on how copper binding may regulate the activity and intracellular distribution of WNDP, and what role the human copper chaperone Atox1 may play in these processes.
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Affiliation(s)
- Svetlana Lutsenko
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97201, USA.
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199
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Arnesano F, Banci L, Bertini I, Thompsett AR. Solution structure of CopC: a cupredoxin-like protein involved in copper homeostasis. Structure 2002; 10:1337-47. [PMID: 12377120 DOI: 10.1016/s0969-2126(02)00858-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The structure of the metal-free form of CopC, a protein involved in copper homeostasis, has been obtained. The fold is a Greek key beta barrel similar to that of functionally unrelated blue copper proteins but with important structural variations. The protein binds one equivalent of copper (II) with relatively high affinity and contains a cluster of conserved residues (His1, Glu27, Asp89, and His91) which could form a water-accessible metal binding site. The structure also reveals a loop containing the M(X)(n)M motif which is present in a number of proteins also involved in copper homeostasis. The present structure represents a link between copper-trafficking proteins and cupredoxins. Within a structural and genomic analysis, the role of CopC in copper trafficking is discussed.
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Affiliation(s)
- Fabio Arnesano
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Sesto Fiorentino, Florence, Italy
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Li S, Rosen BP, Borges-Walmsley MI, Walmsley AR. Evidence for cooperativity between the four binding sites of dimeric ArsD, an As(III)-responsive transcriptional regulator. J Biol Chem 2002; 277:25992-6002. [PMID: 11980902 DOI: 10.1074/jbc.m201619200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ArsD is a trans-acting repressor of the arsRDABC operon that confers resistance to arsenicals and antimonials in Escherichia coli. It possesses two-pairs of vicinal cysteine residues, Cys(12)-Cys(13) and Cys(112)-Cys(113), that potentially form separate binding sites for the metalloids that trigger dissociation of ArsD from the operon. However, as a homodimer it has four vicinal cysteine pairs. Titration of the steady-state fluorescence of ArsD with metalloids revealed positive cooperativity, with a Hill coefficient of 2, between these sites. Disruption of the Cys(112)-Cys(113) site by mutagenesis of arsD, but not the Cys(12)-Cys(13) site, largely abolished this cooperativity, indicative of interactions between adjacent Cys(112)-Cys(113) sites within the dimer. The kinetics of metalloid binding were determined by stopped flow spectroscopy; the rate increased in a sigmoidal manner, with a Hill coefficient of 4, indicating that the pre-steady-state measurements reported cooperativity between all four sites of the dimer rather than just the intermolecular interactions reported by the steady-state measurements. The kinetics of Sb(III) displacement by As(III) revealed that the metalloid-binding sites behave differentially, with the rapid exchange of As(III) for Sb(III) at one site retarding the release of Sb(III) from the other sites. We propose a model involving the sequential binding and release of metalloids by the four binding sites of dimeric ArsD, with only one site releasing free metalloids.
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Affiliation(s)
- Song Li
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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