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Raimunda D, Elso-Berberián G. Functional characterization of the CDF transporter SMc02724 (SmYiiP) in Sinorhizobium meliloti: Roles in manganese homeostasis and nodulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:3203-11. [PMID: 25242380 DOI: 10.1016/j.bbamem.2014.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 09/11/2014] [Accepted: 09/12/2014] [Indexed: 01/29/2023]
Abstract
In bacteria, membrane transporters of the cation diffusion facilitator (CDF) family participate in Zn(2+), Fe(2+), Mn(2+), Co(2+) and Ni(2+) homeostasis. The functional role during infection processes for several members has been shown to be linked to the specificity of transport. Sinorhizobium meliloti has two homologous CDF genes with unknown transport specificity. Here we evaluate the role played by the CDF SMc02724 (SmYiiP). The deletion mutant strain of SmYiiP (ΔsmyiiP) showed reduced in vitro growth fitness only in the presence of Mn(2+). Incubation of ΔsmyiiP and WT cells with sub-lethal Mn(2+) concentrations resulted in a 2-fold increase of the metal only in the mutant strain. Normal levels of resistance to Mn(2+) were attained by complementation with the gene SMc02724 under regulation of its endogenous promoter. In vitro, liposomes with incorporated heterologously expressed pure protein accumulated several transition metals. However, only the transport rate of Mn(2+) was increased by imposing a transmembrane H(+) gradient. Nodulation assays in alfalfa plants showed that the strain ΔsmyiiP induced a lower number of nodules than in plants infected with the WT strain. Our results indicate that Mn(2+) homeostasis in S. meliloti is required for full infection capacity, or nodule function, and that the specificity of transport in vivo of SmYiiP is narrowed down to Mn(2+) by a mechanism involving the proton motive force.
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Affiliation(s)
- Daniel Raimunda
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina.
| | - Graciela Elso-Berberián
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
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52
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Le Brun NE. Copper in Prokaryotes. BINDING, TRANSPORT AND STORAGE OF METAL IONS IN BIOLOGICAL CELLS 2014. [DOI: 10.1039/9781849739979-00461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The ability of copper to cycle its oxidation state, and to form high-affinity complexes with a range of biologically relevant ligands, underpins the central role that this metal plays in prokaryotic processes such as respiration, oxidative stress response, the nitrogen cycle and pigmentation. However, the very properties that nature has exploited also mean that copper is extremely toxic. To minimize this toxicity, while also ensuring sufficient supply of the metal, complex systems of trafficking evolved to facilitate transport of copper (as Cu(I)) across membranes and its targeted distribution within the cytoplasm, membrane and periplasm. The past 20 years have seen our understanding of such systems grow enormously, and atomic/molecular and mechanistic detail of many of the major cellular trafficking components is now available. This chapter begins with a discussion of the chemistry of copper that is relevant for understanding the role of this metal throughout life. The subsequent focus is then on current understanding of copper homeostasis in prokaryotes, with eukaryotic copper homeostasis dealt with in the following chapters. The chapter aims to provide a chemical perspective on these complex biological systems, emphasizing the importance of thermodynamic and kinetic properties of copper and the complexes it forms.
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Affiliation(s)
- Nick E. Le Brun
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia Norwich Research Park Norwich NR4 7TJ UK
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53
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Padilla-Benavides T, George Thompson AM, McEvoy MM, Argüello JM. Mechanism of ATPase-mediated Cu+ export and delivery to periplasmic chaperones: the interaction of Escherichia coli CopA and CusF. J Biol Chem 2014; 289:20492-501. [PMID: 24917681 DOI: 10.1074/jbc.m114.577668] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellular copper homeostasis requires transmembrane transport and compartmental trafficking while maintaining the cell essentially free of uncomplexed Cu(2+/+). In bacteria, soluble cytoplasmic and periplasmic chaperones bind and deliver Cu(+) to target transporters or metalloenzymes. Transmembrane Cu(+)-ATPases couple the hydrolysis of ATP to the efflux of cytoplasmic Cu(+). Cytosolic Cu(+) chaperones (CopZ) interact with a structural platform in Cu(+)-ATPases (CopA) and deliver copper into the ion permeation path. CusF is a periplasmic Cu(+) chaperone that supplies Cu(+) to the CusCBA system for efflux to the extracellular milieu. In this report, using Escherichia coli CopA and CusF, direct Cu(+) transfer from the ATPase to the periplasmic chaperone was observed. This required the specific interaction of the Cu(+)-bound form of CopA with apo-CusF for subsequent metal transfer upon ATP hydrolysis. As expected, the reverse Cu(+) transfer from CusF to CopA was not observed. Mutation of CopA extracellular loops or the electropositive surface of CusF led to a decrease in Cu(+) transfer efficiency. On the other hand, mutation of Met and Glu residues proposed to be part of the metal exit site in the ATPase yielded enzymes with lower turnover rates, although Cu(+) transfer was minimally affected. These results show how soluble chaperones obtain Cu(+) from transmembrane transporters. Furthermore, by explaining the movement of Cu(+) from the cytoplasmic pool to the extracellular milieu, these data support a mechanism by which cytoplasmic Cu(+) can be precisely directed to periplasmic targets via specific transporter-chaperone interactions.
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Affiliation(s)
- Teresita Padilla-Benavides
- From the Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609 and
| | | | - Megan M McEvoy
- the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
| | - José M Argüello
- From the Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609 and
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54
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Patel SJ, Padilla-Benavides T, Collins JM, Argüello JM. Functional diversity of five homologous Cu+-ATPases present in Sinorhizobium meliloti. MICROBIOLOGY-SGM 2014; 160:1237-1251. [PMID: 24662147 DOI: 10.1099/mic.0.079137-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Copper is an important element in host-microbe interactions, acting both as a catalyst in enzymes and as a potential toxin. Cu(+)-ATPases drive cytoplasmic Cu(+) efflux and protect bacteria against metal overload. Many pathogenic and symbiotic bacteria contain multiple Cu(+)-ATPase genes within particular genetic environments, suggesting alternative roles for each resulting protein. This hypothesis was tested by characterizing five homologous Cu(+)-ATPases present in the symbiotic organism Sinorhizobium meliloti. Mutation of each gene led to different phenotypes and abnormal nodule development in the alfalfa host. Distinct responses were detected in free-living S. meliloti mutant strains exposed to metal and redox stresses. Differential gene expression was detected under Cu(+), oxygen or nitrosative stress. These observations suggest that CopA1a maintains the cytoplasmic Cu(+) quota and its expression is controlled by Cu(+) levels. CopA1b is also regulated by Cu(+) concentrations and is required during symbiosis for bacteroid maturation. CopA2-like proteins, FixI1 and FixI2, are necessary for the assembly of two different cytochrome c oxidases at different stages of bacterial life. CopA3 is a phylogenetically distinct Cu(+)-ATPase that does not contribute to Cu(+) tolerance. It is regulated by redox stress and required during symbiosis. We postulated a model where non-redundant homologous Cu(+)-ATPases, operating under distinct regulation, transport Cu(+) to different target proteins.
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Affiliation(s)
- Sarju J Patel
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
| | - Teresita Padilla-Benavides
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
| | - Jessica M Collins
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
| | - José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
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55
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Abstract
UNLABELLED Copper is an essential micronutrient used as a metal cofactor by a variety of enzymes, including cytochrome c oxidase (Cox). In all organisms from bacteria to humans, cellular availability and insertion of copper into target proteins are tightly controlled due to its toxicity. The major subunit of Cox contains a copper atom that is required for its catalytic activity. Previously, we identified CcoA (a member of major facilitator superfamily transporters) as a component required for cbb3-type Cox production in the Gram-negative, facultative phototroph Rhodobacter capsulatus. Here, first we demonstrate that CcoA is a cytoplasmic copper importer. Second, we show that bypass suppressors of a ccoA deletion mutant suppress cbb3-Cox deficiency by increasing cellular copper content and sensitivity. Third, we establish that these suppressors are single-base-pair insertion/deletions located in copA, encoding the major P1B-type ATP-dependent copper exporter (CopA) responsible for copper detoxification. A copA deletion alone has no effect on cbb3-Cox biogenesis in an otherwise wild-type background, even though it rescues the cbb3-Cox defect in the absence of CcoA and renders cells sensitive to copper. We conclude that a hitherto unknown functional interplay between the copper importer CcoA and the copper exporter CopA controls intracellular copper homeostasis required for cbb3-Cox production in bacteria like R. capsulatus. IMPORTANCE Copper (Cu) is an essential micronutrient required for many processes in the cell. It is found as a cofactor for heme-copper containing cytochrome c oxidase enzymes at the terminus of the respiratory chains of aerobic organisms by catalyzing reduction of dioxygen (O2) to water. Defects in the biogenesis and copper insertion into cytochrome c oxidases lead to mitochondrial diseases in humans. This work shows that a previously identified Cu transporter (CcoA) is a Cu importer and illustrates the link between two Cu transporters, the importer CcoA and the exporter CopA, required for Cu homeostasis and Cu trafficking to cytochrome c oxidase in the cell.
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56
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Copper-transporting P-type ATPases use a unique ion-release pathway. Nat Struct Mol Biol 2013; 21:43-8. [PMID: 24317491 DOI: 10.1038/nsmb.2721] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 10/11/2013] [Indexed: 11/09/2022]
Abstract
Heavy metals in cells are typically regulated by PIB-type ATPases. The first structure of the class, a Cu(+)-ATPase from Legionella pneumophila (LpCopA), outlined a copper transport pathway across the membrane, which was inferred to be occluded. Here we show by molecular dynamics simulations that extracellular water solvated the transmembrane (TM) domain, results indicative of a Cu(+)-release pathway. Furthermore, a new LpCopA crystal structure determined at 2.8-Å resolution, trapped in the preceding E2P state, delineated the same passage, and site-directed-mutagenesis activity assays support a functional role for the conduit. The structural similarities between the TM domains of the two conformations suggest that Cu(+)-ATPases couple dephosphorylation and ion extrusion differently than do the well-characterized PII-type ATPases. The ion pathway explains why certain Menkes' and Wilson's disease mutations impair protein function and points to a site for inhibitors targeting pathogens.
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57
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Raimunda D, Long JE, Padilla-Benavides T, Sassetti CM, Argüello JM. Differential roles for the Co(2+) /Ni(2+) transporting ATPases, CtpD and CtpJ, in Mycobacterium tuberculosis virulence. Mol Microbiol 2013; 91:185-97. [PMID: 24255990 DOI: 10.1111/mmi.12454] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2013] [Indexed: 11/29/2022]
Abstract
The genome of Mycobacterium tuberculosis encodes two paralogous P1 B 4 -ATPases, CtpD (Rv1469) and CtpJ (Rv3743). Both proteins showed ATPase activation by Co(2+) and Ni(2+) , and both appear to be required for metal efflux from the cell. However, using a combination of biochemical and genetic studies we found that these proteins play non-redundant roles in virulence and metal efflux. CtpJ expression is induced by Co(2+) and this protein possesses a relatively high turnover rate. A ctpJ deletion mutant accumulated Co(2+) , indicating that this ATPase controls cytoplasmic metal levels. In contrast, CtpD expression is induced by redox stressors and this protein displays a relatively low turnover rate. A ctpD mutant failed to accumulate metal, suggesting an alternative cellular function. ctpD is cotranscribed with two thioredoxin genes trxA (Rv1470), trxB (Rv1471), and an enoyl-coA hydratase (Rv1472), indicating a possible role for CtpD in the metallation of these redox-active proteins. Supporting this, in vitro metal binding assays showed that TrxA binds Co(2+) and Ni(2+) . Mutation of ctpD, but not ctpJ, reduced bacterial fitness in the mouse lung, suggesting that redox maintenance, but not Co(2+) accumulation, is important for growth in vivo.
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Affiliation(s)
- Daniel Raimunda
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
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58
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Argüello JM, Raimunda D, Padilla-Benavides T. Mechanisms of copper homeostasis in bacteria. Front Cell Infect Microbiol 2013; 3:73. [PMID: 24205499 PMCID: PMC3817396 DOI: 10.3389/fcimb.2013.00073] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 10/17/2013] [Indexed: 01/27/2023] Open
Abstract
Copper is an important micronutrient required as a redox co-factor in the catalytic centers of enzymes. However, free copper is a potential hazard because of its high chemical reactivity. Consequently, organisms exert a tight control on Cu(+) transport (entry-exit) and traffic through different compartments, ensuring the homeostasis required for cuproprotein synthesis and prevention of toxic effects. Recent studies based on biochemical, bioinformatics, and metalloproteomics approaches, reveal a highly regulated system of transcriptional regulators, soluble chaperones, membrane transporters, and target cuproproteins distributed in the various bacterial compartments. As a result, new questions have emerged regarding the diversity and apparent redundancies of these components, their irregular presence in different organisms, functional interactions, and resulting system architectures.
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Affiliation(s)
- José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute Worcester, MA, USA
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59
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Molecular basis of active copper resistance mechanisms in Gram-negative bacteria. Cell Biol Toxicol 2013; 29:397-405. [PMID: 24072389 PMCID: PMC3847284 DOI: 10.1007/s10565-013-9262-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 09/16/2013] [Indexed: 10/26/2022]
Abstract
Copper is a metallic element that is crucial for cell metabolism; however, in extended concentrations, it is toxic for all living organisms. The dual nature of copper has forced organisms, including bacteria, to keep a tight hold on cellular copper content. This challenge has led to the evolution of complex mechanisms that on one hand enable them to deliver the essential element and on the other to protect cells against its toxicity. Such mechanisms have been found in both eukaryotic and prokaryotic cells. In bacteria a number of different systems such as extra- and intracellular sequestration, enzymatic detoxification, and metal removal from the cell enabling them to survive in the presence of high concentration of copper have been identified. Gram-negative bacteria, due to their additional compartment, need to deal with both cytoplasmic and periplasmic copper. Therefore, these bacteria have evolved intricate and precisely regulated systems which interact with each other. In this review the active mechanisms of copper resistance at their molecular level are discussed.
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60
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Badarau A, Baslé A, Firbank SJ, Dennison C. Crosstalk between Cu(I) and Zn(II) homeostasis via Atx1 and cognate domains. Chem Commun (Camb) 2013; 49:8000-2. [PMID: 23926594 PMCID: PMC3763678 DOI: 10.1039/c3cc42709a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The copper metallochaperone Atx1 and the N-terminal metal-binding domain of a copper-transporting ATP-ase can form tight Zn(II)-mediated hetero-complexes in both cyanobacteria and humans. Copper and zinc homeostasis could be linked by metal binding to these CXXC-containing proteins.
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Affiliation(s)
- Adriana Badarau
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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61
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Azzouzi A, Steunou AS, Durand A, Khalfaoui-Hassani B, Bourbon ML, Astier C, Bollivar DW, Ouchane S. Coproporphyrin III excretion identifies the anaerobic coproporphyrinogen III oxidase HemN as a copper target in the Cu⁺-ATPase mutant copA⁻ of Rubrivivax gelatinosus. Mol Microbiol 2013; 88:339-51. [PMID: 23448658 DOI: 10.1111/mmi.12188] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2013] [Indexed: 01/25/2023]
Abstract
Two genes encoding structurally similar Copper P1B -type ATPases can be identified in several genomes. Notwithstanding the high sequence and structural similarities these ATPases held, it has been suggested that they fulfil distinct physiological roles. In deed, we have shown that the Cu(+) -ATPase CtpA is required only for the activity of cuproproteins in the purple bacterium Rubrivivax gelatinosus; herein, we show that CopA is not directly required for cytochrome c oxidase but is vital for copper tolerance. Interestingly, excess copper in the copA(-) mutant resulted in a substantial decrease of the cytochrome c oxidase and the photosystem under microaerobic and anaerobic conditions together with the extrusion of coproporphyrin III. The data indicated that copper targeted the tetrapyrrole biosynthesis pathway at the level of the coproporphyrinogen III oxidase HemN and thereby affects the oxidase and the photosystem. This is the first in vivo demonstration that copper, like oxygen, affects tetrapyrrole biosynthesis presumably at the level of the SAM and [4Fe-4S] containing HemN enzyme. In light of these results and similar findings in Escherichia coli, the potential role of copper ions in the evolution of [4Fe-4S] enzymes and the Cu(+) -ATPases is discussed.
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Affiliation(s)
- Asma Azzouzi
- CNRS, CGM, UPR 3404, Université Paris Sud, 1 Ave. de la Terrasse Gif sur Yvette, F-91198, France
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62
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Influence of copper resistance determinants on gold transformation by Cupriavidus metallidurans strain CH34. J Bacteriol 2013; 195:2298-308. [PMID: 23475973 DOI: 10.1128/jb.01951-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cupriavidus metallidurans is associated with gold grains and may be involved in their formation. Gold(III) complexes influence the transcriptome of C. metallidurans (F. Reith et al., Proc. Natl. Acad. Sci. U. S. A. 106:17757-17762, 2009), leading to the upregulation of genes involved in the detoxification of reactive oxygen species and metal ions. In a systematic study, the involvement of these systems in gold transformation was investigated. Treatment of C. metallidurans cells with Au(I) complexes, which occur in this organism's natural environment, led to the upregulation of genes similar to those observed for treatment with Au(III) complexes. The two indigenous plasmids of C. metallidurans, which harbor several transition metal resistance determinants, were not involved in resistance to Au(I/III) complexes nor in their transformation to metallic nanoparticles. Upregulation of a cupA-lacZ fusion by the MerR-type regulator CupR with increasing Au(III) concentrations indicated the presence of gold ions in the cytoplasm. A hypothesis stating that the Gig system detoxifies gold complexes by the uptake and reduction of Au(III) to Au(I) or Au(0) reminiscent to detoxification of Hg(II) was disproven. ZupT and other secondary uptake systems for transition metal cations influenced Au(III) resistance but not the upregulation of the cupA-lacZ fusion. The two copper-exporting P-type ATPases CupA and CopF were also not essential for gold resistance. The copABCD determinant on chromosome 2, which encodes periplasmic proteins involved in copper resistance, was required for full gold resistance in C. metallidurans. In conclusion, biomineralization of gold particles via the reduction of mobile Au(I/III) complexes in C. metallidurans appears to primarily occur in the periplasmic space via copper-handling systems.
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63
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Srivastava P, Kowshik M. Mechanisms of metal resistance and homeostasis in haloarchaea. ARCHAEA (VANCOUVER, B.C.) 2013; 2013:732864. [PMID: 23533331 PMCID: PMC3600143 DOI: 10.1155/2013/732864] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 12/20/2012] [Accepted: 01/10/2013] [Indexed: 11/20/2022]
Abstract
Haloarchaea are the predominant microflora of hypersaline econiches such as solar salterns, soda lakes, and estuaries where the salinity ranges from 35 to 400 ppt. Econiches like estuaries and solar crystallizer ponds may contain high concentrations of metals since they serve as ecological sinks for metal pollution and also as effective traps for river borne metals. The availability of metals in these econiches is determined by the type of metal complexes formed and the solubility of the metal species at such high salinity. Haloarchaea have developed specialized mechanisms for the uptake of metals required for various key physiological processes and are not readily available at high salinity, beside evolving resistance mechanisms for metals with high solubility. The present paper seeks to give an overview of the main molecular mechanisms involved in metal tolerance in haloarchaea and focuses on factors such as salinity and metal speciation that affect the bioavailability of metals to haloarchaea. Global transcriptomic analysis during metal stress in these organisms will help in determining the various factors differentially regulated and essential for metal physiology.
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Affiliation(s)
- Pallavee Srivastava
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, K K Birla Goa Campus, NH-17B, Zuarinagar, Goa 403 726, India
| | - Meenal Kowshik
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, K K Birla Goa Campus, NH-17B, Zuarinagar, Goa 403 726, India
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64
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Abstract
As a trace element copper has an important role in cellular function like many other transition metals. Its ability to undergo redox changes [Cu(I) ↔ Cu(II)] makes copper an ideal cofactor in enzymes catalyzing electron transfers. However, this redox change makes copper dangerous for a cell since it is able to be involved in Fenton-like reactions creating reactive oxygen species (ROS). Cu(I) also is a strong soft metal and can attack and destroy iron-sulfur clusters thereby releasing iron which can in turn cause oxidative stress. Therefore, copper homeostasis has to be highly balanced to ensure proper cellular function while avoiding cell damage.Throughout evolution bacteria and archaea have developed a highly regulated balance in copper metabolism. While for many prokaryotes copper uptake seems to be unspecific, others have developed highly sophisticated uptake mechanisms to ensure the availability of sufficient amounts of copper. Within the cytoplasm copper is sequestered by various proteins and molecules, including specific copper chaperones, to prevent cellular damage. Copper-containing proteins are usually located in the cytoplasmic membrane with the catalytic domain facing the periplasm, in the periplasm of Gram-negative bacteria, or they are secreted, limiting the necessity of copper to accumulate in the cytoplasm. To prevent cellular damage due to excess copper, bacteria and archaea have developed various copper detoxification strategies. In this chapter we attempt to give an overview of the mechanisms employed by bacteria and archaea to handle copper and the importance of the metal for cellular function as well as in the global nutrient cycle.
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Affiliation(s)
- Christopher Rensing
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1870, Frederiksberg C, Denmark
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65
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Osman D, Patterson CJ, Bailey K, Fisher K, Robinson NJ, Rigby SEJ, Cavet JS. The copper supply pathway to aSalmonellaCu,Zn-superoxide dismutase (SodCII) involves P1B-type ATPase copper efflux and periplasmic CueP. Mol Microbiol 2012; 87:466-77. [DOI: 10.1111/mmi.12107] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2012] [Indexed: 11/26/2022]
Affiliation(s)
- Deenah Osman
- Life Sciences; Michael Smith Building; University of Manchester; Manchester; M13 9PT; UK
| | - Carl J. Patterson
- The Biophysical Sciences Institute; Department of Chemistry; School of Biological and Biomedical Sciences; University of Durham; Durham; DH1 3LE; UK
| | - Kathryn Bailey
- Life Sciences; Michael Smith Building; University of Manchester; Manchester; M13 9PT; UK
| | - Karl Fisher
- Life Sciences; Manchester Institute of Biotechnology; University of Manchester; 131 Princess Street; Manchester; M1 7DN; UK
| | - Nigel J. Robinson
- The Biophysical Sciences Institute; Department of Chemistry; School of Biological and Biomedical Sciences; University of Durham; Durham; DH1 3LE; UK
| | - Stephen E. J. Rigby
- Life Sciences; Manchester Institute of Biotechnology; University of Manchester; 131 Princess Street; Manchester; M1 7DN; UK
| | - Jennifer S. Cavet
- Life Sciences; Michael Smith Building; University of Manchester; Manchester; M13 9PT; UK
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66
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Padilla-Benavides T, McCann CJ, Argüello JM. The mechanism of Cu+ transport ATPases: interaction with CU+ chaperones and the role of transient metal-binding sites. J Biol Chem 2012. [PMID: 23184962 DOI: 10.1074/jbc.m112.420810] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cu(+)-ATPases are membrane proteins that couple the hydrolysis of ATP to the efflux of cytoplasmic Cu(+). In cells, soluble chaperone proteins bind and distribute cytoplasmic Cu(+), delivering the ion to the transmembrane metal-binding sites in the ATPase. The structure of Legionella pneumophila Cu(+)-ATPase (Gourdon, P., Liu, X. Y., Skjørringe, T., Morth, J. P., Møller, L. B., Pedersen, B. P., and Nissen, P. (2011) Nature 475, 59-64) shows that a kinked transmembrane segment forms a "platform" exposed to the cytoplasm. In addition, neighboring invariant Met, Asp, and Glu are located at the "entrance" of the ion path. Mutations of amino acids in these regions of the Archaeoglobus fulgidus Cu(+)-ATPase CopA do not affect ATPase activity in the presence of Cu(+) free in solution. However, Cu(+) bound to the corresponding chaperone (CopZ) could not activate the mutated ATPases, and in parallel experiments, CopZ was unable to transfer Cu(+) to CopA. Furthermore, mutation of a specific electronegative patch on the CopZ surface abolishes the ATPase activation and Cu(+) transference, indicating that the region is required for the CopZ-CopA interaction. Moreover, the data suggest that the interaction is driven by the complementation of the electropositive platform in the ATPase and the electronegative Cu(+) chaperone. This docking likely places the Cu(+) proximal to the conserved carboxyl and thiol groups in the entrance site that induce metal release from the chaperone via ligand exchange. The initial interaction of Cu(+) with the pump is transient because Cu(+) is transferred from the entrance site to transmembrane metal-binding sites involved in transmembrane translocation.
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Affiliation(s)
- Teresita Padilla-Benavides
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA
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67
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Hernández-Montes G, Argüello JM, Valderrama B. Evolution and diversity of periplasmic proteins involved in copper homeostasis in gamma proteobacteria. BMC Microbiol 2012; 12:249. [PMID: 23122209 PMCID: PMC3548706 DOI: 10.1186/1471-2180-12-249] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 10/25/2012] [Indexed: 12/15/2022] Open
Abstract
Background Different systems contributing to copper homeostasis in bacteria have been described in recent years involving periplasmic and transport proteins that provide resistance via metal efflux to the extracellular media (CopA/Cue, Cus, Cut, and Pco). The participation of these proteins in the assembly of membrane, periplasmic and secreted cuproproteins has also been postulated. The integration and interrelation of these systems and their apparent redundancies are less clear since they have been studied in alternative systems. Based on the idea that cellular copper is not free but rather it is transferred via protein-protein interactions, we hypothesized that systems would coevolve and be constituted by set numbers of essential components. Results By the use of a phylogenomic approach we identified the distribution of 14 proteins previously characterized as members of homeostasis systems in the genomes of 268 gamma proteobacteria. Only 3% of the genomes presented the complete systems and 5% of them, all intracellular parasites, lacked the 14 genes. Surprisingly, copper homeostatic pathways did not behave as evolutionary units with particular species assembling different combinations of basic functions. The most frequent functions, and probably because of its distribution the most vital, were copper extrusion from the cytoplasm to the periplasm performed by CopA and copper export from the cytoplasm to the extracellular space performed by CusC, which along with the remaining 12 proteins, assemble in nine different functional repertoires. Conclusions These observations suggest complex evolutionary dynamics and still unexplored interactions to achieve copper homeostasis, challenging some of the molecular transport mechanism proposed for these systems.
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Affiliation(s)
- Georgina Hernández-Montes
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av Universidad 2001 Col, Chamilpa, Cuernavaca, Mor CP 62210, México
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68
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Gupta A, Lutsenko S. Evolution of copper transporting ATPases in eukaryotic organisms. Curr Genomics 2012; 13:124-33. [PMID: 23024604 PMCID: PMC3308323 DOI: 10.2174/138920212799860661] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 09/22/2011] [Accepted: 09/29/2011] [Indexed: 11/22/2022] Open
Abstract
Copper is an essential nutrient for most life forms, however in excess it can be harmful. The ATP-driven copper pumps (Copper-ATPases) play critical role in living organisms by maintaining appropriate copper levels in cells and tissues. These evolutionary conserved polytopic membrane proteins are present in all phyla from simplest life forms (bacteria) to highly evolved eukaryotes (Homo sapiens). The presumed early function in metal detoxification remains the main function of Copper-ATPases in prokaryotic kingdom. In eukaryotes, in addition to removing excess copper from the cell, Copper-ATPases have another equally important function - to supply copper to copper dependent enzymes within the secretory pathway. This review focuses on the origin and diversification of Copper ATPases in eukaryotic organisms. From a single Copper ATPase in protozoans, a divergence into two functionally distinct ATPases is observed with the evolutionary appearance of chordates. Among the key functional domains of Copper-ATPases, the metal-binding N-terminal domain could be responsible for functional diversification of the copper ATPases during the course of evolution.
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Affiliation(s)
- Arnab Gupta
- Department of Physiology, Johns Hopkins University, Baltimore, MD 21205, USA
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69
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Zielazinski EL, Cutsail GE, Hoffman BM, Stemmler TL, Rosenzweig AC. Characterization of a cobalt-specific P(1B)-ATPase. Biochemistry 2012; 51:7891-900. [PMID: 22971227 DOI: 10.1021/bi3006708] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The P(1B)-type ATPases are a ubiquitous family of P-type ATPases involved in the transport of transition metal ions. Divided into subclasses based on sequence characteristics and substrate specificity, these integral membrane transporters play key roles in metal homeostasis, metal tolerance, and the biosynthesis of metalloproteins. The P(1B-4)-ATPases have the simplest architecture of the five P(1B)-ATPase families and have been suggested to play a role in Co(2+) transport. A P(1B-4)-ATPase from Sulfitobacter sp. NAS-14.1, designated sCoaT, has been cloned, expressed, and purified. Activity assays indicate that sCoaT is specific for Co(2+). A single Co(2+) binding site is present, and optical, electron paramagnetic resonance, and X-ray absorption spectroscopic data are consistent with tetrahedral coordination by oxygen and nitrogen ligands, including a histidine and likely a water. Surprisingly, there is no evidence for coordination by sulfur. Mutation of a conserved cysteine residue, Cys 327, in the signature transmembrane Ser-Pro-Cys metal binding motif does not abolish the ATP hydrolysis activity or affect the spectroscopic analysis, establishing that this residue is not involved in the initial Co(2+) binding by sCoaT. In contrast, replacements of conserved transmembrane residues Ser 325, His 657, Glu 658, and Thr 661 with alanine abolish ATP hydrolysis activity and Co(2+) binding, indicating that these residues are necessary for Co(2+) transport. These data represent the first in vitro characterization of a P(1B-4)-ATPase and its Co(2+) binding site.
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Affiliation(s)
- Eliza L Zielazinski
- Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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70
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Blaby-Haas CE, Merchant SS. The ins and outs of algal metal transport. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1823:1531-52. [PMID: 22569643 PMCID: PMC3408858 DOI: 10.1016/j.bbamcr.2012.04.010] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 04/20/2012] [Accepted: 04/23/2012] [Indexed: 10/28/2022]
Abstract
Metal transporters are a central component in the interaction of algae with their environment. They represent the first line of defense to cellular perturbations in metal concentration, and by analyzing algal metal transporter repertoires, we gain insight into a fundamental aspect of algal biology. The ability of individual algae to thrive in environments with unique geochemistry, compared to non-algal species commonly used as reference organisms for metal homeostasis, provides an opportunity to broaden our understanding of biological metal requirements, preferences and trafficking. Chlamydomonas reinhardtii is the best developed reference organism for the study of algal biology, especially with respect to metal metabolism; however, the diversity of algal niches necessitates a comparative genomic analysis of all sequenced algal genomes. A comparison between known and putative proteins in animals, plants, fungi and algae using protein similarity networks has revealed the presence of novel metal metabolism components in Chlamydomonas including new iron and copper transporters. This analysis also supports the concept that, in terms of metal metabolism, algae from similar niches are more related to one another than to algae from the same phylogenetic clade. This article is part of a Special Issue entitled: Cell Biology of Metals.
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71
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Lohmeyer E, Schröder S, Pawlik G, Trasnea PI, Peters A, Daldal F, Koch HG. The ScoI homologue SenC is a copper binding protein that interacts directly with the cbb₃-type cytochrome oxidase in Rhodobacter capsulatus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:2005-15. [PMID: 22771512 DOI: 10.1016/j.bbabio.2012.06.621] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 06/27/2012] [Accepted: 06/28/2012] [Indexed: 11/28/2022]
Abstract
Sco proteins are widespread assembly factors for the Cu(A) centre of aa₃-type cytochrome oxidases in eukaryotic and prokaryotic organisms. However, Sco homologues are also found in bacteria like Rhodobacter capsulatus which lack aa₃-type cytochrome oxidases and instead use a cbb₃-type cytochrome oxidase (cbb₃ Cox) without a Cu(A) centre as a terminal oxidase. In the current study, we have analyzed the role of Sco (SenC) during cbb₃ Cox assembly in R. capsulatus. In agreement with earlier works, we found a strong cbb₃ Cox defect in the absence of SenC that impairs the steady-state stability of the CcoN, CcoO and CcoP core subunits, without the accumulation of detectable assembly intermediates. In vivo cross-linking results demonstrate that SenC is in close proximity to the CcoP and CcoH subunits of cbb₃ Cox, suggesting that SenC interacts directly with cbb₃ Cox during its assembly. SenC binds copper and the cbb₃ Cox assembly defect in the absence of SenC can be rescued by the addition of least 0.5μM Cu. Neither copper nor SenC influenced the transcription of the ccoNOQP operon encoding for cbb₃ Cox. Transcription of senC itself was also not influenced by Cu unless the putative Cu-export ATPase CcoI was absent. As CcoI is specifically required for the cbb₃ Cox assembly, these data provide a direct link between Cu delivery to cbb₃ Cox and SenC function.
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Affiliation(s)
- Eva Lohmeyer
- Institut für Biochemie und Molekularbiologie, ZBMZ, Stefan-Meier-Strasse 17, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.
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72
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Schushan M, Bhattacharjee A, Ben-Tal N, Lutsenko S. A structural model of the copper ATPase ATP7B to facilitate analysis of Wilson disease-causing mutations and studies of the transport mechanism. Metallomics 2012; 4:669-78. [PMID: 22692182 DOI: 10.1039/c2mt20025b] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The copper-transporting ATPase ATP7B has an essential role in human physiology, particularly for the liver and brain function. Inactivation of ATP7B is associated with a severe hepato-neurologic disorder, Wilson disease (WD). Hundreds of WD related mutations have been identified in ATP7B to date. The low frequency and the compound-heterozygous nature of causative mutations complicate the analysis of individual mutants and the establishment of genotype-phenotype correlations. To facilitate studies of disease-causing mutations and mechanistic understanding of WD, we have homology-modelled the ATP7B core (residues 643-1377) using the recent structure of the bacterial copper-ATPase LCopA as a template. The model, supported by evolutionary conservation and hydrophobicity analysis, as well as existing and new mutagenesis data, allows molecular interpretations of experimentally characterized clinical mutations. We also illustrate that structure and conservation can be used to grade potential deleterious effects for many WD mutations, which were clinically detected but have not yet been experimentally characterized. Finally, we compare the structural features of ATP7B and LCopA and discuss specific features of the eukaryotic copper pump.
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Affiliation(s)
- Maya Schushan
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv 69978, Israel.
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73
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Samanovic MI, Ding C, Thiele DJ, Darwin KH. Copper in microbial pathogenesis: meddling with the metal. Cell Host Microbe 2012; 11:106-15. [PMID: 22341460 DOI: 10.1016/j.chom.2012.01.009] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Transition metals such as iron, zinc, copper, and manganese are essential for the growth and development of organisms ranging from bacteria to mammals. Numerous studies have focused on the impact of iron availability during bacterial and fungal infections, and increasing evidence suggests that copper is also involved in microbial pathogenesis. Not only is copper an essential cofactor for specific microbial enzymes, but several recent studies also strongly suggest that copper is used to restrict pathogen growth in vivo. Here, we review evidence that animals use copper as an antimicrobial weapon and that, in turn, microbes have developed mechanisms to counteract the toxic effects of copper.
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Affiliation(s)
- Marie I Samanovic
- Department of Microbiology, New York University School of Medicine, 550 First Avenue, Medical Science Building 236, New York, NY 10016, USA
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74
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Marrero K, Sánchez A, González LJ, Ledón T, Rodríguez-Ulloa A, Castellanos-Serra L, Pérez C, Fando R. Periplasmic proteins encoded by VCA0261-0260 and VC2216 genes together with copA and cueR products are required for copper tolerance but not for virulence in Vibrio cholerae. MICROBIOLOGY-SGM 2012; 158:2005-2016. [PMID: 22653946 DOI: 10.1099/mic.0.059345-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The bacterial pathogen Vibrio cholerae requires colonizination of the human small intestine to cause cholera. The anaerobic and slightly acidic conditions predominating there enhance toxicity of low copper concentrations and create a selective environment for bacteria with evolved detoxifying mechanisms. We reported previously that the VCA0260, VCA0261 and VC2216 gene products were synthesized only in V. cholerae grown in microaerobiosis or anaerobiosis. Here we show that ORFs VCA0261 and VCA0260 are actually combined into a single gene encoding a 18.7 kDa protein. Bioinformatic analyses linked this protein and the VC2216 gene product to copper tolerance. Following the approach of predict-mutate and test, we describe for the first time, to our knowledge, the copper tolerance systems operating in V. cholerae. Copper susceptibility analyses of mutants in VCA0261-0260, VC2216 or in the putative copper-tolerance-related VC2215 (copA ATPase) and VC0974 (cueR), under aerobic and anaerobic growth, revealed that CopA represents the main tolerance system under both conditions. The VC2216-encoded periplasmic protein contributes to resistance only under anaerobiosis in a CopA-functional background. The locus tag VCA0261-0260 encodes a copper-inducible, CueR-dependent, periplasmic protein, which mediates tolerance in aerobiosis, but under anaerobiosis its role is only evident in CopA knock-out mutants. None of the genes involved in copper homeostasis were required for V. cholerae virulence or colonization in the mouse model. We conclude that copper tolerance in V. cholerae, which lacks orthologues of the periplasmic copper tolerance proteins CueO, CusCFBA and CueP, involves CopA and CueR proteins along with the periplasmic Cot (VCA0261-0260) and CopG (VC2216) V. cholerae homologues.
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Affiliation(s)
- Karen Marrero
- Department of Molecular Biology, National Centre for Scientific Research, PO Box 6412, Havana, Cuba
| | - Aniel Sánchez
- Department of Proteomics, Centre for Genetic Engineering and Biotechnology, PO Box 6162, Havana, Cuba
| | - Luis Javier González
- Department of Proteomics, Centre for Genetic Engineering and Biotechnology, PO Box 6162, Havana, Cuba
| | - Talena Ledón
- Department of Molecular Biology, National Centre for Scientific Research, PO Box 6412, Havana, Cuba
| | - Arielis Rodríguez-Ulloa
- Department of Bioinformatics, Centre for Genetic Engineering and Biotechnology, PO Box 6162, Havana, Cuba
| | - Lila Castellanos-Serra
- Department of Proteomics, Centre for Genetic Engineering and Biotechnology, PO Box 6162, Havana, Cuba
| | - Celso Pérez
- Department of Molecular Biology, National Centre for Scientific Research, PO Box 6412, Havana, Cuba
| | - Rafael Fando
- Department of Molecular Biology, National Centre for Scientific Research, PO Box 6412, Havana, Cuba
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75
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Raimunda D, Long JE, Sassetti CM, Argüello JM. Role in metal homeostasis of CtpD, a Co²⁺ transporting P(1B4)-ATPase of Mycobacterium smegmatis. Mol Microbiol 2012; 84:1139-49. [PMID: 22591178 DOI: 10.1111/j.1365-2958.2012.08082.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Genetic studies in the tuberculosis mouse model have suggested that mycobacterial metal efflux systems, such as the P(1B4)-ATPase CtpD, are important for pathogenesis. The specificity for substrate metals largely determines the function of these ATPases; however, various substrates have been reported for bacterial and plant P(1B4)-ATPases leaving their function uncertain. Here we describe the functional role of the CtpD protein of Mycobacterium smegmatis. An M. smegmatis mutant strain lacking the ctpD gene was hypersensitive to Co²⁺ and Ni²⁺ and accumulated these metals in the cytoplasm. ctpD transcription was induced by both Co²⁺ and superoxide stress. Biochemical characterization of heterologously expressed, affinity-purified CtpD showed that this ATPase is activated by Co²⁺, Ni²⁺ and to a lesser extend Zn²⁺ (20% of maximum activity). The protein was also able to bind one Co²⁺, Ni²⁺ or Zn²⁺ to its transmembrane transport site. These observations indicate that CtpD is important for Co²⁺ and Ni²⁺ homeostasis in M. smegmatis, and that M. tuberculosis CtpD orthologue could be involved in metal detoxification and resisting cellular oxidative stress by modulating the intracellular concentration of these metals.
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Affiliation(s)
- Daniel Raimunda
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA, USA
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76
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Argüello JM, Raimunda D, González-Guerrero M. Metal transport across biomembranes: emerging models for a distinct chemistry. J Biol Chem 2012; 287:13510-7. [PMID: 22389499 DOI: 10.1074/jbc.r111.319343] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Transition metals are essential components of important biomolecules, and their homeostasis is central to many life processes. Transmembrane transporters are key elements controlling the distribution of metals in various compartments. However, due to their chemical properties, transition elements require transporters with different structural-functional characteristics from those of alkali and alkali earth ions. Emerging structural information and functional studies have revealed distinctive features of metal transport. Among these are the relevance of multifaceted events involving metal transfer among participating proteins, the importance of coordination geometry at transmembrane transport sites, and the presence of the largely irreversible steps associated with vectorial transport. Here, we discuss how these characteristics shape novel transition metal ion transport models.
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Affiliation(s)
- José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA.
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77
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A tetrahedral coordination of Zinc during transmembrane transport by P-type Zn(2+)-ATPases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1374-7. [PMID: 22387457 DOI: 10.1016/j.bbamem.2012.02.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 02/15/2012] [Accepted: 02/17/2012] [Indexed: 01/09/2023]
Abstract
Zn(2+) is an essential transition metal required in trace amounts by all living organisms. However, metal excess is cytotoxic and leads to cell damage. Cells rely on transmembrane transporters, with the assistance of other proteins, to establish and maintain Zn(2+) homeostasis. Metal coordination during transport is key to specific transport and unidirectional translocation without the backward release of free metal. The coordination details of Zn(2+) at the transmembrane metal binding site responsible for transport have now been established. Escherichia coli ZntA is a well-characterized Zn(2+)-ATPase responsible for intracellular Zn(2+) efflux. A truncated form of the protein lacking regulatory metal sites and retaining the transport site was constructed. Metrical parameters of the metal-ligand coordination geometry for the zinc bound isolated form were characterized using x-ray absorption spectroscopy (XAS). Our data support a nearest neighbor ligand environment of (O/N)(2)S(2) that is compatible with the proposed invariant metal coordinating residues present in the transmembrane region. This ligand identification and the calculated bond lengths support a tetrahedral coordination geometry for Zn(2+) bound to the TM-MBS of P-type ATPase transporters.
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78
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Völlmecke C, Drees SL, Reimann J, Albers SV, Lübben M. The ATPases CopA and CopB both contribute to copper resistance of the thermoacidophilic archaeon Sulfolobus solfataricus. MICROBIOLOGY-SGM 2012; 158:1622-1633. [PMID: 22361944 DOI: 10.1099/mic.0.055905-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Certain heavy metal ions such as copper and zinc serve as essential cofactors of many enzymes, but are toxic at high concentrations. Thus, intracellular levels have to be subtly balanced. P-type ATPases of the P(IB)-subclass play a major role in metal homeostasis. The thermoacidophile Sulfolobus solfataricus possesses two P(IB)-ATPases named CopA and CopB. Both enzymes are present in cells grown in copper-depleted medium and are accumulated upon an increase in the external copper concentration. We studied the physiological roles of both ATPases by disrupting genes copA and copB. Neither of them affected the sensitivity of S. solfataricus to reactive oxygen species, nor were they a strict prerequisite to the biosynthesis of the copper protein cytochrome oxidase. Deletion mutant analysis demonstrated that CopA is an effective copper pump at low and high copper concentrations. CopB appeared to be a low-affinity copper export ATPase, which was only relevant if the media copper concentration was exceedingly high. CopA and CopB thus act as resistance factors to copper ions at overlapping concentrations. Moreover, growth tests on solid media indicated that both ATPases are involved in resistance to silver.
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Affiliation(s)
- Christian Völlmecke
- Lehrstuhl für Biophysik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Steffen L Drees
- Lehrstuhl für Biophysik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Julia Reimann
- Molecular Biology of Archaea, MPI für Terrestrische Mikrobiologie, Marburg, Karl-von-Frisch-Straße 10, D-35043 Marburg, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, MPI für Terrestrische Mikrobiologie, Marburg, Karl-von-Frisch-Straße 10, D-35043 Marburg, Germany
| | - Mathias Lübben
- Lehrstuhl für Biophysik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
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79
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Coordination chemistry of copper proteins: How nature handles a toxic cargo for essential function. J Inorg Biochem 2012; 107:129-43. [DOI: 10.1016/j.jinorgbio.2011.11.024] [Citation(s) in RCA: 232] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 10/25/2011] [Accepted: 11/15/2011] [Indexed: 01/16/2023]
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80
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Rosenzweig AC, Argüello JM. Toward a molecular understanding of metal transport by P(1B)-type ATPases. CURRENT TOPICS IN MEMBRANES 2012; 69:113-36. [PMID: 23046649 DOI: 10.1016/b978-0-12-394390-3.00005-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The P(1B) family of P-type ATPases couples the transport of cytoplasmic transition metals across biological membranes to the hydrolysis of ATP. These ubiquitous transporters function in maintaining cytoplasmic metal quotas and in the assembly of metalloproteins, and have been classified into subfamilies (P(1B-1)-P(1B-5)) on the basis of their transported substrates (Cu(+), Zn(2+), Cu(2+), and Co(2+)) and signature sequences in their transmembrane segments. In addition, each subgroup presents a characteristic membrane topology and specific regulatory cytoplasmic metal-binding domains. In recent years, significant major aspects of their transport mechanism have been described, including the stoichiometry of transport and the delivery of substrates to transport sites by metallochaperones. Toward understanding their structure, the metal coordination by transport sites has been characterized for Cu(+) and Zn(2+)-ATPases. In addition, atomic resolution structures have been determined, providing key insight into the elements that enable transition metal transport. Because the Cu(+)-transporting ATPases are found in humans and are linked to disease, this subfamily has been the focus of intense study. As a result, significant progress has been made toward understanding Cu(+)-ATPase function on the molecular level, using both the human proteins and the bacterial homologs, most notably the CopA proteins from Archaeoglobus fulgidus, Bacillus subtilis, and Thermotoga maritima. This chapter thus focuses on the mechanistic and structural information obtained by studying these latter Cu(+)-ATPases, with some consideration of how these aspects might differ for the other subfamilies of P(1B)-ATPases.
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Affiliation(s)
- Amy C Rosenzweig
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA.
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82
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Cyanobacterial metallochaperone inhibits deleterious side reactions of copper. Proc Natl Acad Sci U S A 2011; 109:95-100. [PMID: 22198771 DOI: 10.1073/pnas.1117515109] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Copper metallochaperones supply copper to cupro-proteins through copper-mediated protein-protein-interactions and it has been hypothesized that metallochaperones thereby inhibit copper from causing damage en route. Evidence is presented in support of this latter role for cyanobacterial metallochaperone, Atx1. In cyanobacteria Atx1 contributes towards the supply of copper to plastocyanin inside thylakoids but it is shown here that in copper-replete medium, copper can reach plastocyanin without Atx1. Unlike metallochaperone-independent copper-supply to superoxide dismutase in eukaryotes, glutathione is not essential for Atx1-independent supply to plastocyanin: Double mutants missing atx1 and gshB (encoding glutathione synthetase) accumulate the same number of atoms of copper per cell in the plastocyanin pool as wild type. Critically, Δatx1ΔgshB are hypersensitive to elevated copper relative to wild type cells and also relative to ΔgshB single mutants with evidence that hypersensitivity arises due to the mislocation of copper to sites for other metals including iron and zinc. The zinc site on the amino-terminal domain (ZiaA(N)) of the P(1)-type zinc-transporting ATPase is especially similar to the copper site of the Atx1 target PacS(N), and ZiaA(N) will bind Cu(I) more tightly than zinc. An NMR model of a substituted-ZiaA(N)-Cu(I)-Atx1 heterodimer has been generated making it possible to visualize a juxtaposition of residues surrounding the ZiaA(N) zinc site, including Asp(18), which normally repulse Atx1. Equivalent repulsion between bacterial copper metallochaperones and the amino-terminal regions of P(1)-type ATPases for metals other than Cu(I) is conserved, again consistent with a role for copper metallochaperones to withhold copper from binding sites for other metals.
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83
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Ekici S, Pawlik G, Lohmeyer E, Koch HG, Daldal F. Biogenesis of cbb(3)-type cytochrome c oxidase in Rhodobacter capsulatus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:898-910. [PMID: 22079199 DOI: 10.1016/j.bbabio.2011.10.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Accepted: 10/31/2011] [Indexed: 11/18/2022]
Abstract
The cbb(3)-type cytochrome c oxidases (cbb(3)-Cox) constitute the second most abundant cytochrome c oxidase (Cox) group after the mitochondrial-like aa(3)-type Cox. They are present in bacteria only, and are considered to represent a primordial innovation in the domain of Eubacteria due to their phylogenetic distribution and their similarity to nitric oxide (NO) reductases. They are crucial for the onset of many anaerobic biological processes, such as anoxygenic photosynthesis or nitrogen fixation. In addition, they are prevalent in many pathogenic bacteria, and important for colonizing low oxygen tissues. Studies related to cbb(3)-Cox provide a fascinating paradigm for the biogenesis of sophisticated oligomeric membrane proteins. Complex subunit maturation and assembly machineries, producing the c-type cytochromes and the binuclear heme b(3)-Cu(B) center, have to be coordinated precisely both temporally and spatially to yield a functional cbb(3)-Cox enzyme. In this review we summarize our current knowledge on the structure, regulation and assembly of cbb(3)-Cox, and provide a highly tentative model for cbb(3)-Cox assembly and formation of its heme b(3)-Cu(B) binuclear center. This article is part of a Special Issue entitled: Biogenesis/Assembly of Respiratory Enzyme Complexes.
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Affiliation(s)
- Seda Ekici
- University of Pennsylvania, Department of Biology, Philadelphia, PA 19104, USA
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Argüello JM, González-Guerrero M, Raimunda D. Bacterial transition metal P(1B)-ATPases: transport mechanism and roles in virulence. Biochemistry 2011; 50:9940-9. [PMID: 21999638 DOI: 10.1021/bi201418k] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
P(1B)-type ATPases are polytopic membrane proteins that couple the hydrolysis of ATP to the efflux of cytoplasmic transition metals. This paper reviews recent progress in our understanding of the structure and function of these proteins in bacteria. These are members of the P-type superfamily of transport ATPases. Cu(+)-ATPases are the most frequently observed and best-characterized members of this group of transporters. However, bacterial genomes show diverse arrays of P(1B)-type ATPases with a range of substrates (Cu(+), Zn(2+), Co(2+)). Furthermore, because of the structural similarities among transitions metals, these proteins can also transport nonphysiological substrates (Cd(2+), Pb(2+), Au(+), Ag(+)). P(1B)-type ATPases have six or eight transmembrane segments (TM) with metal coordinating amino acids in three core TMs flanking the cytoplasmic domain responsible for ATP binding and hydrolysis. In addition, regulatory cytoplasmic metal binding domains are present in most P(1B)-type ATPases. Central to the transport mechanism is the binding of the uncomplexed metal to these proteins when cytoplasmic substrates are bound to chaperone and chelating molecules. Metal binding to regulatory sites is through a reversible metal exchange among chaperones and cytoplasmic metal binding domains. In contrast, the chaperone-mediated metal delivery to transport sites appears as a largely irreversible event. P(1B)-ATPases have two overarching physiological functions: to maintain cytoplasmic metal levels and to provide metals for the periplasmic assembly of metalloproteins. Recent studies have shown that both roles are critical for bacterial virulence, since P(1B)-ATPases appear key to overcome high phagosomal metal levels and are required for the assembly of periplasmic and secreted metalloproteins that are essential for survival in extreme oxidant environments.
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Affiliation(s)
- José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA.
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Badarau A, Dennison C. Thermodynamics of copper and zinc distribution in the cyanobacterium Synechocystis PCC 6803. Proc Natl Acad Sci U S A 2011; 108:13007-12. [PMID: 21778408 PMCID: PMC3156197 DOI: 10.1073/pnas.1101448108] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Copper is supplied to plastocyanin for photosynthesis and cytochrome c oxidase for respiration in the thylakoids of Synechocystis PCC 6803 by the membrane-bound P-type ATPases CtaA and PacS, and the metallochaperone Atx1. We have determined the Cu(I) affinities of all of the soluble proteins and domains in this pathway. The Cu(I) affinities of the trafficking proteins range from 5 × 10(16) to 5 × 10(17) M(-1) at pH 7.0, consistent with values for homologues. Unusually, Atx1 binds Cu(I) significantly tighter than the metal-binding domains (MBDs) of CtaA and PacS (CtaA(N) and PacS(N)), and equilibrium copper exchange constants of approximately 0.2 are obtained for transfer to the MBDs. Dimerization of Atx1 increases the affinity for Cu(I), but the loop 5 His61 residue has little influence. The MBD of the zinc exporter ZiaA (ZiaA(N)) exhibits an almost identical Cu(I) affinity, and Cu(I) exchange with Atx1, as CtaA(N) and PacS(N), and the relative stabilities of the complexes must enable the metallochaperone to distinguish between the MBDs. The binding of potentially competing zinc to the trafficking proteins has been studied. ZiaA(N) has the highest Zn(II) affinity and thermodynamics could be important for zinc removal from the cell. Plastocyanin has a Cu(I) affinity of 2.6 × 10(17) M(-1), 15-fold tighter than that of the Cu(A) site of cytochrome c oxidase, highlighting the need for specific mechanisms to ensure copper delivery to both of these targets. The narrow range of Cu(I) affinities for the cytoplasmic copper proteins in Synechocystis will facilitate relocation when copper is limiting.
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Affiliation(s)
- Adriana Badarau
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Christopher Dennison
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
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