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Melenbacher A, Stillman MJ. Metallothionein-3: 63 Cu(I) binds to human 68 Zn 7 -βα MT3 with no preference for Cu 4 -β cluster formation. FEBS J 2023; 290:4316-4341. [PMID: 37165729 DOI: 10.1111/febs.16812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/25/2023] [Accepted: 05/09/2023] [Indexed: 05/12/2023]
Abstract
Human metallothioneins (MTs) are involved in binding the essential elements, Cu(I) and Zn(II), and the toxic element, Cd(II), in metal-thiolate clusters using 20 reduced cysteines. The brain-specific MT3 binds a mixture of Cu(I) and Zn(II) in vivo. Its metallation properties are critically important because of potential connections between Cu, Zn and neurodegenerative diseases. We report that the use of isotopically pure 63 Cu(I) and 68 Zn(II) greatly enhances the element resolution in the ESI-mass spectral data revealing species with differing Cu:Zn ratios but the same total number of metals. Room temperature phosphorescence and circular dichroism spectral data measured in parallel with ESI-mass spectral data identified the presence of specific Cu(I)-thiolate clusters in the presence of Zn(II). A series of Cu(I)-thiolate clusters form following Cu(I) addition to apo MT3: the two main clusters that form are a Cu6 cluster in the β domain followed by a Cu4 cluster in the α domain. 63 Cu(I) addition to 68 Zn7 -MT3 results in multiple species, including clustered Cu5 Zn5 -MT3 and Cu9 Zn3 -MT3. We assign the domain location of the metals for Cu5 Zn5 -MT3 as a Cu5 Zn1 -β cluster and a Zn4 -α cluster and for Cu9 Zn3 -MT3 as a Cu6 -β cluster and a Cu3 Zn3 -α cluster. While many reports of the average MT3 metal content exist, determining the exact Cu,Zn stoichiometry has proven very difficult even with native ESI-MS. The work in this paper solves the ambiguity introduced by the overlap of the naturally abundant Cu(I) and Zn(II) isotopes. Contrary to other reports, there is no indication of a major fraction of Cu4 -β-Znn -α-MT3 forming.
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Affiliation(s)
- Adyn Melenbacher
- Department of Chemistry, The University of Western Ontario, London, Canada
| | - Martin J Stillman
- Department of Chemistry, The University of Western Ontario, London, Canada
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2
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Melenbacher A, Heinlein L, Hartwig A, Stillman MJ. 63Cu(I) binding to human kidney 68Zn7-βα MT1A: determination of Cu(I)-thiolate cluster domain specificity from ESI-MS and room temperature phosphorescence spectroscopy. Metallomics 2023; 15:mfac101. [PMID: 36583699 PMCID: PMC9846682 DOI: 10.1093/mtomcs/mfac101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 12/29/2022] [Indexed: 12/31/2022]
Abstract
Mammalian metallothioneins (MTs) are important proteins in Zn(II) and Cu(I) homeostasis with the Zn(II) and Cu(I) binding to the 20 cysteines in metal-thiolate clusters. Previous electrospray ionization (ESI) mass spectrometric (MS) analyses of Cu(I) binding to Zn7-MT were complicated by significant overlap of the natural abundance isotopic patterns for Zn(II) and Cu(I) leading to impossibly ambiguous stoichiometries. In this paper, isotopically pure 63Cu(I) and 68Zn(II) allowed determination of the specific stoichiometries in the 68 Zn,63Cu-βα MT1A species formed following the stepwise addition of 63Cu(I) to 68Zn7-βα MT1A. These species were characterized by ESI-MS and room temperature emission spectroscopy. The key species that form and their emission band centres are Zn5Cu5-βα MT1A (λ = 684 nm), Zn4Cu6-βα MT1A (λ = 750 nm), Zn3Cu9-βα MT1A (λ = 750 nm), Zn2Cu10-βα MT1A (λ = 750 nm), and Zn1Cu14-βα MT1A (λ = 634 nm). The specific domain stoichiometry of each species was determined by assessing the species forming following 63Cu(I) addition to the 68Zn3-β MT1A and 68Zn4-α MT1A domain fragments. The domain fragment emission suggests that Zn5Cu5-βα MT1A contains a Zn1Cu5-β cluster and the Zn4Cu6-βα MT1A, Zn3Cu9-βα MT1A, and Zn2Cu10-βα MT1A each contain a Cu6-β cluster. The species forming with >10 mol. eq. of 63Cu(I) in βα-MT1A exhibit emission from the Cu6-β cluster and an α domain cluster. This high emission intensity is seen at the end of the titrations of 68Zn7-βα MT1A and the 68Zn4-α MT1A domain fragment suggesting that the initial presence of the Zn(II) results in clustered Cu(I) binding in the α domain.
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Affiliation(s)
- Adyn Melenbacher
- Department of Chemistry, The University of Western Ontario, 1151 Richmond St., London, Ontario, ON N6A 5B7, Canada
| | - Lina Heinlein
- Department of Chemistry, The University of Western Ontario, 1151 Richmond St., London, Ontario, ON N6A 5B7, Canada
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Karlsruhe, Baden-Württemberg, 76131, Germany
| | - Andrea Hartwig
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Karlsruhe, Baden-Württemberg, 76131, Germany
| | - Martin J Stillman
- Department of Chemistry, The University of Western Ontario, 1151 Richmond St., London, Ontario, ON N6A 5B7, Canada
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García-Risco M, Calatayud S, Niederwanger M, Albalat R, Palacios Ò, Capdevila M, Dallinger R. Two Unconventional Metallothioneins in the Apple Snail Pomacea bridgesii Have Lost Their Metal Specificity during Adaptation to Freshwater Habitats. Int J Mol Sci 2020; 22:ijms22010095. [PMID: 33374169 PMCID: PMC7796288 DOI: 10.3390/ijms22010095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 01/08/2023] Open
Abstract
Metallothioneins (MTs) are a diverse group of proteins responsible for the control of metal homeostasis and detoxification. To investigate the impact that environmental conditions might have had on the metal-binding abilities of these proteins, we have characterized the MTs from the apple snail Pomacea bridgesii, a gastropod species belonging to the class of Caenogastropoda with an amphibious lifestyle facing diverse situations of metal bioavailability. P. bridgesii has two structurally divergent MTs, named PbrMT1 and PbrMT2, that are longer than other gastropod MTs due to the presence of extra sequence motifs and metal-binding domains. We have characterized the Zn(II), Cd(II), and Cu(I) binding abilities of these two MTs after their heterologous expression in E. coli. Our results have revealed that despite their structural differences, both MTs share an unspecific metal-binding character, and a great ability to cope with elevated amounts of different metal ions. Our analyses have also revealed slight divergences in their metal-binding features: PbrMT1 shows a more pronounced Zn(II)-thionein character than PbrMT2, while the latter has a stronger Cu(I)-thionein character. The characterization of these two unconventional PbrMTs supports the loss of the metal-binding specificity during the evolution of the MTs of the Ampullariid family, and further suggests an evolutionary link of this loss with the adaptation of these gastropod lineages to metal-poor freshwater habitats.
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Affiliation(s)
- Mario García-Risco
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain; (M.G.-R.); (Ò.P.); (M.C.)
| | - Sara Calatayud
- Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, E-08028 Barcelona, Spain; (S.C.); (R.A.)
| | - Michael Niederwanger
- Institute of Zoology, Center of Molecular Biosciences, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria;
| | - Ricard Albalat
- Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, E-08028 Barcelona, Spain; (S.C.); (R.A.)
| | - Òscar Palacios
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain; (M.G.-R.); (Ò.P.); (M.C.)
| | - Mercè Capdevila
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain; (M.G.-R.); (Ò.P.); (M.C.)
| | - Reinhard Dallinger
- Institute of Zoology, Center of Molecular Biosciences, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria;
- Correspondence:
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Dong S, Shirzadeh M, Fan L, Laganowsky A, Russell DH. Ag + Ion Binding to Human Metallothionein-2A Is Cooperative and Domain Specific. Anal Chem 2020; 92:8923-8932. [PMID: 32515580 PMCID: PMC8114364 DOI: 10.1021/acs.analchem.0c00829] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Metallothioneins (MTs) constitute a family of cysteine-rich proteins that play key biological roles for a wide range of metal ions, but unlike many other metalloproteins, the structures of apo- and partially metalated MTs are not well understood. Here, we combine nano-electrospray ionization-mass spectrometry (ESI-MS) and nano-ESI-ion mobility (IM)-MS with collision-induced unfolding (CIU), chemical labeling using N-ethylmaleimide (NEM), and both bottom-up and top-down proteomics in an effort to better understand the metal binding sites of the partially metalated forms of human MT-2A, viz., Ag4-MT. The results for Ag4-MT are then compared to similar results obtained for Cd4-MT. The results show that Ag4-MT is a cooperative product, and data from top-down and bottom-up proteomics mass spectrometry analysis combined with NEM labeling revealed that all four Ag+ ions of Ag4-MT are bound to the β-domain. The binding sites are identified as Cys13, Cys15, Cys19, Cys21, Cys24, and Cys26. While both Ag+ and Cd2+ react with MT to yield cooperative products, i.e., Ag4-MT and Cd4-MT, these products are very different; Ag+ ions of Ag4-MT are located in the β-domain, whereas Cd2+ ions of Cd4-MT are located in the α-domain. Ag6-MT has been reported to be fully metalated in the β-domain, but our data suggest the two additional Ag+ ions are more weakly bound than are the other four. Higher order Agi-MT complexes (i = 7-17) are formed in solutions that contain excess Ag+ ions, and these are assumed to be bound to the α-domain or shared between the two domains. Interestingly, the excess Ag+ ions are displaced upon addition of NEM to this solution to yield predominantly Ag4NEM14-MT. Results from CIU suggest that Agi-MT complexes are structurally more ordered and that the energy required to unfold these complexes increases as the number of coordinated Ag+ increases.
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Affiliation(s)
- Shiyu Dong
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Mehdi Shirzadeh
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Liqi Fan
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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Comes G, Fernandez-Gayol O, Molinero A, Giralt M, Capdevila M, Atrian S, Hidalgo J. Mouse metallothionein-1 and metallothionein-2 are not biologically interchangeable in an animal model of multiple sclerosis, EAE. Metallomics 2020; 11:327-337. [PMID: 30543238 DOI: 10.1039/c8mt00285a] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Mouse metallothionein-1 and 2 (MT1 and MT2) are often considered physiologically equivalent, because they are normally regulated coordinately by a wide range of stimuli, and it is assumed that in vivo they will be normally fully loaded with zinc(ii) (Zn7-MT1/2), although other metal ions, such as copper(i), may be eventually found as well. However, mouse MT2, in contrast to MT1, exhibits a preference for Zn(ii) coordination in comparison to that for Cu(i), which might underlie putatively different biological functions for these two mammalian isoforms. We have characterized the effects of exogenously administered mouse MT1 and MT2, and of transgenic Mt1 overexpression, in an animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE), by active immunization with MOG35-55 peptide. Mice treated daily with MT2 showed a significant amelioration of the clinical course, with decreased peak and cumulative scores and delayed onset of EAE. In contrast, treatment with MT1 or its transgenic overexpression only caused a non-significant trend. MT2 treatment preserved better the myelin of the spinal cord, and the pattern of leukocyte infiltrates and gene expression are compatible with an inhibitory effect on neuroinflammation. Splenocytes from these animals in culture responded adequately to MOG35-55 peptide, but a bias for a Th2 profile seemed to be present in the MT2-treated mice. Interestingly, MT1 but not MT2 decreased the number of cytokines in the serum. The present results indicate that mouse MT1 and MT2 are not biologically interchangeable in the EAE model.
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Affiliation(s)
- Gemma Comes
- Animal Physiology Unit, C/Vall Moronta s/n, Department of Cellular Biology, Physiology and Immunology, Faculty of Biosciences, and Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
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6
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Melenbacher A, Korkola NC, Stillman MJ. The pathways and domain specificity of Cu(i) binding to human metallothionein 1A. Metallomics 2020; 12:1951-1964. [DOI: 10.1039/d0mt00215a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We describe the sequential formation of 3 key Cu(i)–thiolate clusters in human metallothionein 1A using a combination of ESI-MS and phosphorescence lifetime methods.
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Affiliation(s)
- Adyn Melenbacher
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
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Palacios Ò, Jiménez-Martí E, Niederwanger M, Gil-Moreno S, Zerbe O, Atrian S, Dallinger R, Capdevila M. Analysis of Metal-Binding Features of the Wild Type and Two Domain-Truncated Mutant Variants of Littorina littorea Metallothionein Reveals Its Cd-Specific Character. Int J Mol Sci 2017; 18:E1452. [PMID: 28684668 PMCID: PMC5535943 DOI: 10.3390/ijms18071452] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 06/27/2017] [Accepted: 07/01/2017] [Indexed: 11/16/2022] Open
Abstract
After the resolution of the 3D structure of the Cd₉-aggregate of the Littorina littorea metallothionein (MT), we report here a detailed analysis of the metal binding capabilities of the wild type MT, LlwtMT, and of two truncated mutants lacking either the N-terminal domain, Lltr2MT, or both the N-terminal domain, plus four extra flanking residues (SSVF), Lltr1MT. The recombinant synthesis and in vitro studies of these three proteins revealed that LlwtMT forms unique M₉-LlwtMT complexes with Zn(II) and Cd(II), while yielding a complex mixture of heteronuclear Zn,Cu-LlwtMT species with Cu(I). As expected, the truncated mutants gave rise to unique M₆-LltrMT complexes and Zn,Cu-LltrMT mixtures of lower stoichiometry with respect to LlwtMT, with the SSVF fragment having an influence on their metal binding performance. Our results also revealed a major specificity, and therefore a better metal-coordinating performance of the three proteins for Cd(II) than for Zn(II), although the analysis of the Zn(II)/Cd(II) displacement reaction clearly demonstrates a lack of any type of cooperativity in Cd(II) binding. Contrarily, the analysis of their Cu(I) binding abilities revealed that every LlMT domain is prone to build Cu₄-aggregates, the whole MT working by modules analogously to, as previously described, certain fungal MTs, like those of C. neoformans and T. mesenterica. It is concluded that the Littorina littorea MT is a Cd-specific protein that (beyond its extended binding capacity through an additional Cd-binding domain) confers to Littorina littorea a particular adaptive advantage in its changeable marine habitat.
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Affiliation(s)
- Òscar Palacios
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain.
| | - Elena Jiménez-Martí
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, E-08028 Barcelona, Spain.
| | - Michael Niederwanger
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
| | - Selene Gil-Moreno
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain.
| | - Oliver Zerbe
- Department of Chemistry, University of Zurich, 8057 Zurich, Switzerland.
| | - Sílvia Atrian
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, E-08028 Barcelona, Spain.
| | - Reinhard Dallinger
- Institute of Zoology and Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
| | - Mercè Capdevila
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain.
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Hu S, Ye B, Yi X, Cao Z, Wu D, Shen C, Wang J. Dumbbell-shaped metallothionein-templated silver nanoclusters with applications in cell imaging and Hg2+ sensing. Talanta 2016; 155:272-7. [DOI: 10.1016/j.talanta.2016.04.055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/23/2016] [Accepted: 04/24/2016] [Indexed: 10/21/2022]
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9
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Iturbe-Espinoza P, Gil-Moreno S, Lin W, Calatayud S, Palacios Ò, Capdevila M, Atrian S. The Fungus Tremella mesenterica Encodes the Longest Metallothionein Currently Known: Gene, Protein and Metal Binding Characterization. PLoS One 2016; 11:e0148651. [PMID: 26882011 PMCID: PMC4755600 DOI: 10.1371/journal.pone.0148651] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/21/2016] [Indexed: 12/05/2022] Open
Abstract
Fungal Cu-thioneins, and among them, the paradigmatic Neurospora crassa metallothionein (MT) (26 residues), were once considered as the shortest MTs -the ubiquitous, versatile metal-binding proteins- among all organisms, and thus representatives of their primeval forms. Nowadays, fungal MTs of diverse lengths and sequence features are known, following the huge heterogeneity of the Kingdom of Fungi. At the opposite end of N. crassa MT, the recently reported Cryptococcus neoformans CnMT1 and CnMT2 (122 and 186 aa) constitute the longest reported fungal MTs, having been identified as virulence factors of this pathogen. CnMTs are high-capacity Cu-thioneins that appear to be built by tandem amplification of a basic unit, a 7-Cys segment homologous to N. crassa MT. Here, we report the in silico, in vivo and in vitro study of a still longer fungal MT, belonging to Tremella mesenterica (TmMT), a saprophytic ascomycete. The TmMT gene has 10 exons, and it yields a 779-bp mature transcript that encodes a 257 residue-long protein. This MT is also built by repeated fragments, but of variable number of Cys: six units of the 7-Cys building blocks-CXCX3CSCPPGXCXCAXCP-, two fragments of six Cys, plus three Cys at the N-terminus. TmMT metal binding abilities have been analyzed through the spectrophotometric and spectrometric characterization of its recombinant Zn-, Cd- and Cu-complexes. Results allow it to be unambiguous classified as a Cu-thionein, also of extraordinary coordinating capacity. According to this feature, when the TmMT cDNA is expressed in MT-devoid yeast cells, it is capable of restoring a high Cu tolerance level. Since it is not obvious that T. mesenterica shares the same physiological needs for a high capacity Cu-binding protein with C. neoformans, the existence of this peculiar MT might be better explained on the basis of a possible role in Cu-handling for the Cu-enzymes responsible in lignin degradation pathways.
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Affiliation(s)
- Paul Iturbe-Espinoza
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Selene Gil-Moreno
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Weiyu Lin
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Sara Calatayud
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Òscar Palacios
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Mercè Capdevila
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Sílvia Atrian
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- * E-mail:
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Espart A, Gil-Moreno S, Palacios Ò, Capdevila M, Atrian S. Understanding the 7-Cys module amplification of C. neoformans metallothioneins: how high capacity Cu-binding polypeptides are built to neutralize host nutritional immunity. Mol Microbiol 2015; 98:977-92. [PMID: 26287377 DOI: 10.1111/mmi.13171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2015] [Indexed: 11/27/2022]
Abstract
Cryptococcus neoformans metallothioneins (MTs), CnMT1 and CnMT2, have been identified as essential infectivity and virulence factors of this pathogen. Both MTs are unusually long Cu-thioneins, exhibiting protein architecture and metal-binding abilities compatible with the hypothesis of resulting from three and five tandem repetitions of 7-Cys motives, respectively, each of them folding into Cu5-clusters. Through the study of the Zn(II)- and Cu(I)-binding capabilities of several CnMT1 truncated mutants, we show that a 7-Cys segment of CnMT1 folds into Cu5-species, of additive capacity when joined in tandem. All the obtained Cu-complexes share practically similar architectural features, if judging by their almost equivalent CD fingerprints, and they also share their capacity to restore copper tolerance in MT-devoid yeast cells. Besides the analysis of the modular composition of these long fungal MTs, we evaluate the features of the Cys-rich stretch spacer and flanking sequences that allow the construction of stable metal clusters by adjacent union of binding modules. Overall, our data support a mechanism by which some microbial MTs may have evolved to enlarge their original metal co-ordination capacity under the specific selective pressure of counteracting the Cu-based immunity mechanisms evolved by the infected hosts.
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Affiliation(s)
- Anna Espart
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, 08028, Barcelona, Spain
| | - Selene Gil-Moreno
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193, Cerdanyola de Vallès, Spain
| | - Òscar Palacios
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193, Cerdanyola de Vallès, Spain
| | - Mercè Capdevila
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193, Cerdanyola de Vallès, Spain
| | - Sílvia Atrian
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, 08028, Barcelona, Spain
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Espart A, Marín M, Gil-Moreno S, Palacios Ò, Amaro F, Martín-González A, Gutiérrez JC, Capdevila M, Atrian S. Hints for metal-preference protein sequence determinants: different metal binding features of the five tetrahymena thermophila metallothioneins. Int J Biol Sci 2015; 11:456-71. [PMID: 25798065 PMCID: PMC4366644 DOI: 10.7150/ijbs.11060] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 01/21/2015] [Indexed: 11/12/2022] Open
Abstract
The metal binding preference of metallothioneins (MTs) groups them in two extreme subsets, the Zn/Cd- and the Cu-thioneins. Ciliates harbor the largest MT gene/protein family reported so far, including 5 paralogs that exhibit relatively low sequence similarity, excepting MTT2 and MTT4. In Tetrahymena thermophila, three MTs (MTT1, MTT3 and MTT5) were considered Cd-thioneins and two (MTT2 and MTT4) Cu-thioneins, according to gene expression inducibility and phylogenetic analysis. In this study, the metal-binding abilities of the five MTT proteins were characterized, to obtain information about the folding and stability of their cognate- and non-cognate metal complexes, and to characterize the T. thermophila MT system at protein level. Hence, the five MTTs were recombinantly synthesized as Zn2+-, Cd2+- or Cu+-complexes, which were analyzed by electrospray mass spectrometry (ESI-MS), circular dichroism (CD), and UV-vis spectrophotometry. Among the Cd-thioneins, MTT1 and MTT5 were optimal for Cd2+ coordination, yielding unique Cd17- and Cd8- complexes, respectively. When binding Zn2+, they rendered a mixture of Zn-species. Only MTT5 was capable to coordinate Cu+, although yielding heteronuclear Zn-, Cu-species or highly unstable Cu-homometallic species. MTT3 exhibited poor binding abilities both for Cd2+ and for Cu+, and although not optimally, it yielded the best result when coordinating Zn2+. The two Cu-thioneins, MTT2 and MTT4 isoforms formed homometallic Cu-complexes (major Cu20-MTT) upon synthesis in Cu-supplemented hosts. Contrarily, they were unable to fold into stable Cd-complexes, while Zn-MTT species were only recovered for MTT4 (major Zn10-MTT4). Thus, the metal binding preferences of the five T. thermophila MTs correlate well with their previous classification as Cd- and Cu-thioneins, and globally, they can be classified from Zn/Cd- to Cu-thioneins according to the gradation: MTT1>MTT5>MTT3>MTT4>MTT2. The main mechanisms underlying the evolution and specialization of the MTT metal binding preferences may have been internal tandem duplications, presence of doublet and triplet Cys patterns in Zn/Cd-thioneins, and optimization of site specific amino acid determinants (Lys for Zn/Cd- and Asn for Cu-coordination).
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Affiliation(s)
- Anna Espart
- 1. Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, 08028-Barcelona, Spain
| | - Maribel Marín
- 2. Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193-Cerdanyola del Vallès (Barcelona), Spain
| | - Selene Gil-Moreno
- 2. Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193-Cerdanyola del Vallès (Barcelona), Spain
| | - Òscar Palacios
- 2. Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193-Cerdanyola del Vallès (Barcelona), Spain
| | - Francisco Amaro
- 3. Departamento de Microbiología-III, Facultad de Biología, Universidad Complutense, 28040-Madrid, Spain
| | - Ana Martín-González
- 3. Departamento de Microbiología-III, Facultad de Biología, Universidad Complutense, 28040-Madrid, Spain
| | - Juan C Gutiérrez
- 3. Departamento de Microbiología-III, Facultad de Biología, Universidad Complutense, 28040-Madrid, Spain
| | - Mercè Capdevila
- 2. Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193-Cerdanyola del Vallès (Barcelona), Spain
| | - Sílvia Atrian
- 1. Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, 08028-Barcelona, Spain
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Palacios Ò, Espart A, Espín J, Ding C, Thiele DJ, Atrian S, Capdevila M. Full characterization of the Cu-, Zn-, and Cd-binding properties of CnMT1 and CnMT2, two metallothioneins of the pathogenic fungus Cryptococcus neoformans acting as virulence factors. Metallomics 2014; 6:279-91. [PMID: 24317230 DOI: 10.1039/c3mt00266g] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report here the full characterization of the metal binding abilities of CnMT1 and CnMT2, two Cryptococcus neoformans proteins recently identified as metallothioneins (MTs), which have been shown to play a crucial role in the virulence and pathogenicity of this human-infecting fungus. In this work, we first performed a thorough in silico study of the CnMT1 and CnMT2 genes, cDNAs and corresponding encoded products. Subsequently, the Zn(II)-, Cd(II)- and Cu(I) binding abilities of both proteins were fully determined through the analysis of the metal-to-protein stoichiometries and the structural features (determined by ESI-MS, CD, ICP-AES and UV-vis spectroscopies) of the corresponding recombinant Zn-, Cd- and Cu-MT preparations synthesized in metal-enriched media. Finally, the analysis of the Zn/Cd and Zn/Cu replacement processes of the respective Zn-MT complexes when allowed to react with Cd(II) or Cu(I) aqueous solutions was performed. Comprehensive consideration of all gathered results allows us to consider both isoforms as genuine copper-thioneins, and led to the identification of unprecedented Cu5-core clusters in MTs. CnMT1 and CnMT2 polypeptides appear to be evolutionarily related to the small fungal MTs, probably by ancient tandem-duplication events responding to a highly selective pressure to chelate copper, and far from the properties of Zn- and Cd-thioneins. Finally, we propose a modular structure of the Cu-CnMT1 and Cu-CnMT2 complexes on the basis of Cu5 clusters, concordantly with the modular structure of the sequence of CnMT1 and CnMT2, constituted by three and five Cys-rich units, respectively.
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Affiliation(s)
- Òscar Palacios
- Dept. de Química, Fac. de Ciències, Universitat Autònoma de Barcelona, 08193-Cerdanyola del Vallès, Barcelona, Spain
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13
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Ultrasensitive determination of DNA sequences by flow injection chemiluminescence using silver ions as labels. Anal Chim Acta 2014; 848:67-73. [DOI: 10.1016/j.aca.2014.07.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 07/17/2014] [Accepted: 07/22/2014] [Indexed: 01/04/2023]
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14
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Cantareus aspersus metallothionein metal binding abilities: The unspecific CaCd/CuMT isoform provides hints about the metal preference determinants in metallothioneins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1694-707. [DOI: 10.1016/j.bbapap.2014.06.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 06/19/2014] [Accepted: 06/20/2014] [Indexed: 11/19/2022]
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15
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Cognate and noncognate metal ion coordination in metal-specific metallothioneins: the Helix pomatia system as a model. J Biol Inorg Chem 2014; 19:923-35. [DOI: 10.1007/s00775-014-1127-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 03/10/2014] [Indexed: 02/03/2023]
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16
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Artells E, Palacios O, Capdevila M, Atrian S. In vivo-folded metal-metallothionein 3 complexes reveal the Cu-thionein rather than Zn-thionein character of this brain-specific mammalian metallothionein. FEBS J 2014; 281:1659-78. [PMID: 24479872 DOI: 10.1111/febs.12731] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/20/2014] [Accepted: 01/24/2014] [Indexed: 11/29/2022]
Abstract
Metallothionein-3 (MT3) is one of the four mammalian metallothioneins (MT), and is constitutively synthesized in the brain. MT3 acts both intracellularly and extracellularly in this organ, performing functions related to neuronal growth and physiological metal (Zn and Cu) handling. It appears to be involved in the prevention of neurodegenerative disorders caused by insoluble Cu-peptide aggregates, as it triggers a Zn-Cu swap that may counteract the deleterious presence of copper in neural tissues. The literature data on MT3 coordination come from studies either on apo-MT3 reconstitution or the reaction of Zn-MT3 with Cu(2+) , an ion that is hardly present inside cells. To ascertain the MT3 metal-binding features in a scenario closer to the reductive cell cytoplasm, a study of the recombinant Zn(2+) , Cd(2+) and Cu(+) complexes of MT3, βMT3, and αMT3, as well as the in vitro Zn(2+) -Cd(2+) and Zn(2+) -Cu(+) replacement processes, is presented here. We conclude that MT3 has a Cu-thionein character that is stronger than that of the MT1 and MT2 isoforms - also present in the mammalian brain - which is mainly contributed by its β domain. In contrast, the α domain retains a high capacity to bind Zn(2+) ions, and, consequently, the entire MT3 peptide shows a peculiar dual ability to handle both metal ions. The nature of the formed Cu(+) -MT3 complexes oscillates from heterometallic Cu6 Zn4 -MT3 to homometallic Cu10 -MT3 major species, in a narrow Cu concentration range. Therefore, the entire MT3 peptide shows a high capacity to bind Cu(+) , provided that this occurs in a nonoxidative milieux. This reflects a peculiar property of this MT isoform, which accurately senses different Cu contents in the environment in which it is synthesized.
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Affiliation(s)
- Ester Artells
- Departament de Química, Universitat Autònoma de Barcelona, Spain; Departament de Genètica, Universitat de Barcelona, Spain
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Camponeschi F, Valensin D, Tessari I, Bubacco L, Dell’Acqua S, Casella L, Monzani E, Gaggelli E, Valensin G. Copper(I)-α-Synuclein Interaction: Structural Description of Two Independent and Competing Metal Binding Sites. Inorg Chem 2013; 52:1358-67. [DOI: 10.1021/ic302050m] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Francesca Camponeschi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro 2, Siena, Italy
| | - Daniela Valensin
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro 2, Siena, Italy
| | - Isabella Tessari
- Department of Biology, University of Padova, Via U. Bassi 58b,
Padova, Italy
| | - Luigi Bubacco
- Department of Biology, University of Padova, Via U. Bassi 58b,
Padova, Italy
| | - Simone Dell’Acqua
- Department of Chemistry, University of Pavia, Via Taramelli 12, Pavia, Italy
| | - Luigi Casella
- Department of Chemistry, University of Pavia, Via Taramelli 12, Pavia, Italy
| | - Enrico Monzani
- Department of Chemistry, University of Pavia, Via Taramelli 12, Pavia, Italy
| | - Elena Gaggelli
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro 2, Siena, Italy
| | - Gianni Valensin
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro 2, Siena, Italy
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The sea urchin metallothionein system: Comparative evaluation of the SpMTA and SpMTB metal-binding preferences. FEBS Open Bio 2013; 3:89-100. [PMID: 23847757 PMCID: PMC3668524 DOI: 10.1016/j.fob.2013.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 01/09/2013] [Accepted: 01/09/2013] [Indexed: 11/23/2022] Open
Abstract
Metallothioneins (MTs) constitute a superfamily of ubiquitous metal-binding proteins of low molecular weight and high Cys content. They are involved in metal homeostasis and detoxification, amongst other proposed biological functions. Two MT isoforms (SpMTA and SpMTB) have been reported in the echinoderm Strongylocentrotus purpuratus (sea urchin), both containing 20 Cys residues and presenting extremely similar sequences, although showing distinct tissular and ontogenic expression patterns. Although exhaustive information is available for the Cd(II)-SpMTA complex, this including the full resolution of its 3D structure, no data has been reported concerning either SpMTA Zn(II) and Cu(I) binding properties, or the characterization of SpMTB at protein level. In this work, both the SpMTA and SpMTB isoforms, as well as their separate α and β domains, have been recombinantly synthesized in the presence of Zn(II), Cd(II) or Cu(II), and the corresponding metal complexes have been analyzed using electrospray mass spectrometry, and CD, ICP-AES and UV-vis spectroscopies. The results clearly show a better performance of isoform A when binding Zn(II) and Cd(II), and of isoform B when coordinating Cu(I). Thus, our results confirm the differential metal binding preference of SpMTA and SpMTB, which, together with the reported induction pattern of the respective genes, highlights how also in Echinodermata the MT polymorphism may be linked to the evolution of different physiological roles.
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Artells E, Palacios Ò, Capdevila M, Atrian S. Mammalian MT1 and MT2 metallothioneins differ in their metal binding abilities. Metallomics 2013; 5:1397-410. [DOI: 10.1039/c3mt00123g] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Guirola M, Pérez-Rafael S, Capdevila M, Palacios O, Atrian S. Metal dealing at the origin of the Chordata phylum: the metallothionein system and metal overload response in amphioxus. PLoS One 2012; 7:e43299. [PMID: 22905252 PMCID: PMC3419175 DOI: 10.1371/journal.pone.0043299] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/19/2012] [Indexed: 11/18/2022] Open
Abstract
Non-vertebrate chordates, specifically amphioxus, are considered of the utmost interest for gaining insight into the evolutionary trends, i.e. differentiation and specialization, of gene/protein systems. In this work, MTs (metallothioneins), the most important metal binding proteins, are characterized for the first time in the cephalochordate subphylum at both gene and protein level, together with the main features defining the amphioxus response to cadmium and copper overload. Two MT genes (BfMT1 and BfMT2) have been identified in a contiguous region of the genome, as well as several ARE (antioxidant response element) and MRE (metal response element) located upstream the transcribed region. Their corresponding cDNAs exhibit identical sequence in the two lancelet species (B. floridae and B. lanceolatum), BfMT2 cDNA resulting from an alternative splicing event. BfMT1 is a polyvalent metal binding peptide that coordinates any of the studied metal ions (Zn, Cd or Cu) rendering complexes stable enough to last in physiological environments, which is fully concordant with the constitutive expression of its gene, and therefore, with a metal homeostasis housekeeping role. On the contrary, BfMT2 exhibits a clear ability to coordinate Cd(II) ions, while it is absolutely unable to fold into stable Cu (I) complexes, even as mixed species. This identifies it as an essential detoxification agent, which is consequently only induced in emergency situations. The cephalochordate MTs are not directly related to vertebrate MTs, neither by gene structure, protein similarity nor metal-binding behavior of the encoded peptides. The closest relative is the echinoderm MT, which confirm proposed phylogenetic relationships between these two groups. The current findings support the existence in most organisms of two types of MTs as for their metal binding preferences, devoted to different biological functions: multivalent MTs for housekeeping roles, and specialized MTs that evolve either as Cd-thioneins or Cu-thioneins, according to the ecophysiological needs of each kind of organisms.
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Affiliation(s)
- Maria Guirola
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.
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21
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Pérez-Rafael S, Kurz A, Guirola M, Capdevila M, Palacios Ò, Atrian S. Is MtnE, the fifth Drosophila metallothionein, functionally distinct from the other members of this polymorphic protein family? Metallomics 2012; 4:342-9. [DOI: 10.1039/c2mt00182a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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The metal binding abilities of Megathura crenulata metallothionein (McMT) in the frame of gastropoda MTs. J Inorg Biochem 2011; 108:84-90. [PMID: 22209022 DOI: 10.1016/j.jinorgbio.2011.11.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 11/13/2011] [Accepted: 11/14/2011] [Indexed: 11/21/2022]
Abstract
Metallothioneins (MTs) are proteins that play a major role in metal homeostasis and/or detoxification in all kind of organisms. The MT gene/protein system of gastropod molluscs provides an invaluable model to study the diversification mechanisms that have enabled MTs to achieve metal-binding specificity through evolution. Most pulmonate gastropods, particularly terrestrial snails, harbor three paralogous isogenes encoding three MT isoforms with different metal binding preferences: the highly specific CdMT and CuMT isoforms, for cadmium and copper respectively, and the unspecific Cd/CuMT isoform. Megathura crenulata is a non-pulmonate gastropod in which only one MT isogene has so far been reported. In order to elucidate the metal binding character of the corresponding peptide (McMT), it has been recombinantly synthesized in the presence of Cd(2+), Zn(2+) or Cu(2+), and the corresponding metal complexes have been analyzed using electrospray mass spectrometry, and CD and UV-visible spectroscopy. The metal-binding traits exhibited by McMT revealed that it is an unspecific MT, similarly to the pulmonate Cd/CuMT isoforms. This is in full concordance with the protein sequence distance analysis in relation to other gastropod MTs.
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Palacios Ò, Atrian S, Capdevila M. Zn- and Cu-thioneins: a functional classification for metallothioneins? J Biol Inorg Chem 2011; 16:991-1009. [DOI: 10.1007/s00775-011-0827-2] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 07/25/2011] [Indexed: 11/25/2022]
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24
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Palacios O, Pagani A, Pérez-Rafael S, Egg M, Höckner M, Brandstätter A, Capdevila M, Atrian S, Dallinger R. Shaping mechanisms of metal specificity in a family of metazoan metallothioneins: evolutionary differentiation of mollusc metallothioneins. BMC Biol 2011; 9:4. [PMID: 21255385 PMCID: PMC3033865 DOI: 10.1186/1741-7007-9-4] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 01/21/2011] [Indexed: 01/29/2023] Open
Abstract
Background The degree of metal binding specificity in metalloproteins such as metallothioneins (MTs) can be crucial for their functional accuracy. Unlike most other animal species, pulmonate molluscs possess homometallic MT isoforms loaded with Cu+ or Cd2+. They have, so far, been obtained as native metal-MT complexes from snail tissues, where they are involved in the metabolism of the metal ion species bound to the respective isoform. However, it has not as yet been discerned if their specific metal occupation is the result of a rigid control of metal availability, or isoform expression programming in the hosting tissues or of structural differences of the respective peptides determining the coordinative options for the different metal ions. In this study, the Roman snail (Helix pomatia) Cu-loaded and Cd-loaded isoforms (HpCuMT and HpCdMT) were used as model molecules in order to elucidate the biochemical and evolutionary mechanisms permitting pulmonate MTs to achieve specificity for their cognate metal ion. Results HpCuMT and HpCdMT were recombinantly synthesized in the presence of Cd2+, Zn2+ or Cu2+ and corresponding metal complexes analysed by electrospray mass spectrometry and circular dichroism (CD) and ultra violet-visible (UV-Vis) spectrophotometry. Both MT isoforms were only able to form unique, homometallic and stable complexes (Cd6-HpCdMT and Cu12-HpCuMT) with their cognate metal ions. Yeast complementation assays demonstrated that the two isoforms assumed metal-specific functions, in agreement with their binding preferences, in heterologous eukaryotic environments. In the snail organism, the functional metal specificity of HpCdMT and HpCuMT was contributed by metal-specific transcription programming and cell-specific expression. Sequence elucidation and phylogenetic analysis of MT isoforms from a number of snail species revealed that they possess an unspecific and two metal-specific MT isoforms, whose metal specificity was achieved exclusively by evolutionary modulation of non-cysteine amino acid positions. Conclusion The Roman snail HpCdMT and HpCuMT isoforms can thus be regarded as prototypes of isoform families that evolved genuine metal-specificity within pulmonate molluscs. Diversification into these isoforms may have been initiated by gene duplication, followed by speciation and selection towards opposite needs for protecting copper-dominated metabolic pathways from nonessential cadmium. The mechanisms enabling these proteins to be metal-specific could also be relevant for other metalloproteins.
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Affiliation(s)
- Oscar Palacios
- Departamento Química, Faculty Ciències, Universitat Autònoma de Barcelona, Spain
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25
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Orihuela R, Monteiro F, Pagani A, Capdevila M, Atrian S. Evidence of Native Metal–S
2−
–Metallothionein Complexes Confirmed by the Analysis of Cup1 Divalent‐Metal‐Ion Binding Properties. Chemistry 2010; 16:12363-72. [PMID: 20839184 DOI: 10.1002/chem.201001125] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Rubén Orihuela
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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26
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Serra-Batiste M, Cols N, Alcaraz LA, Donaire A, González-Duarte P, Vašák M. The metal-binding properties of the blue crab copper specific CuMT-2: a crustacean metallothionein with two cysteine triplets. J Biol Inorg Chem 2010; 15:759-76. [DOI: 10.1007/s00775-010-0644-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 02/24/2010] [Indexed: 10/19/2022]
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27
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Bofill R, Orihuela R, Romagosa M, Domènech J, Atrian S, Capdevila M. Caenorhabditis elegans metallothionein isoform specificity--metal binding abilities and the role of histidine in CeMT1 and CeMT2. FEBS J 2009; 276:7040-56. [PMID: 19860833 DOI: 10.1111/j.1742-4658.2009.07417.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two metallothionein (MT) isoforms have been identified in the model nematode Caenorhabditis elegans: CeMT1 and CeMT2, comprising two polypeptides that are 75 and 63 residues in length, respectively. Both isoforms encompass a conserved cysteine pattern (19 in CeMT1 and 18 in CeMT2) and, most significantly, as a result of their coordinative potential, CeMT1 includes four histidines, whereas CeMT2 has only one. In the present study, we present a comprehensive and comparative analysis of the metal [Zn(II), Cd(II) and Cu(I)] binding abilities of CeMT1 and CeMT2, performed through spectroscopic and spectrometric characterization of the recombinant metal-MT complexes synthesized for wild-type isoforms (CeMT1 and CeMT2), their separate N- and C-terminal moieties (NtCeMT1, CtCeMT1, NtCeMT2 and CtCeMT2) and a DeltaHisCeMT2 mutant. The corresponding in vitro Zn/Cd- and Zn/Cu-replacement and acidification/renaturalization processes have also been studied, as well as protein modification strategies that make it possible to identify and quantify the contribution of the histidine residues to metal coordination. Overall, the data obtained in the present study are consistent with a scenario where both isoforms exhibit a clear preference for divalent metal ion binding, rather than for Cu coordination, although this preference is more pronounced towards cadmium for CeMT2, whereas it is markedly clearer towards Zn for CeMT1. The presence of histidines in these MTs is revealed to be decisive for their coordination performance. In CeMT1, they contribute to the binding of a seventh Zn(II) ion in relation to the M(II)(6)-CeMT2 complexes, both when synthesized in the presence of supplemented Zn(II) or Cd(II). In CeMT2, the unique C-terminal histidine abolishes the Cu-thionein character that this isoform would otherwise exhibit.
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Affiliation(s)
- Roger Bofill
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, Spain
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28
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Dolderer B, Hartmann HJ, Weser U. Metallothioneins in Yeast and Fungi. METALLOTHIONEINS AND RELATED CHELATORS 2009. [DOI: 10.1039/9781847559531-00083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Small cysteine-rich proteins sharing most if not all of the general features used to define the metallothionein (MT) superfamily are found in yeast and fungi. Unlike MTs from mammalian sources, most of the known yeast and fungal MTs are Cu(I) rather than Zn(II) or Cd(II) binding proteins. The sequences of fungal MTs reported so far are quite diverse, in such a way that fungal MTs are assigned to six different families. Family 8 contains the MTs with the highest similarity to the N-terminal domains of mammalian MTs. The best characterized member of this family is isolated from the ascomycete Neurospora crassa. It represents a copper-induced polypeptide of only about 25 amino acid residues and harbors a single cluster made up of six Cu(I) that are bound to its seven cysteine residues. The MTs assigned to families 9 and 10 are MT-1 and MT-2 found in the human pathogenic yeast Candida glabrata. The regulation of these proteins employing a copper sensitive transcription factor shares the same principle as were described for the MTs found in Saccharomyces cerevisiae, Cu-MT and Crs5, that are assigned to families 12 and 13. S. cerevisiae Cu-MT is the only MT, of which the structure including its Cu(I)8-thiolate core has been revealed. It should be emphasized that this is the largest known Cu cluster in biological systems. Besides the presentation of these well studied aspects, the open questions of Cd(II) and Zn(II) binding in yeasts and fungi are addressed and future directions of the MT research are discussed.
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Affiliation(s)
- Benedikt Dolderer
- Anorganische-Biochemie, Interfakultäres Institut für Biochemie, University of Tübingen Hoppe-Seyler-Str. 4 D-72076 Tübingen Germany
| | - Hans-Jürgen Hartmann
- Anorganische-Biochemie, Interfakultäres Institut für Biochemie, University of Tübingen Hoppe-Seyler-Str. 4 D-72076 Tübingen Germany
| | - Ulrich Weser
- Anorganische-Biochemie, Interfakultäres Institut für Biochemie, University of Tübingen Hoppe-Seyler-Str. 4 D-72076 Tübingen Germany
- Centro di Risonanze Magnetiche, University of Florence Via Luigi Sacconi 6 I-50019 Sesto Fiorentino (Firenze) Italy
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Bofill R, Capdevila M, Atrian S. Independent metal-binding features of recombinant metallothioneins convergently draw a step gradation between Zn- and Cu-thioneins. Metallomics 2009; 1:229-34. [DOI: 10.1039/b904953c] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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30
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Distinct characteristics of Ag+ and Cd2+ binding to CopZ from Bacillus subtilis. J Biol Inorg Chem 2008; 13:1011-23. [PMID: 18496720 DOI: 10.1007/s00775-008-0388-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 05/02/2008] [Indexed: 10/22/2022]
Abstract
The chaperone CopZ together with the P-type ATPase transporter CopA constitute a copper-detoxification system in Bacillus subtilis that is commonly found in bacteria and higher cells. Previous studies of the regulation of the copZA operon showed that expression is significantly upregulated in response to elevated concentrations of environmental silver and cadmium, as well as copper. Here, we have used spectroscopic and bioanalytical methods to investigate in detail the capacity of CopZ to bind these metal ions (as Ag(+) and Cd(2+)). We demonstrate that Ag(+) binding mimics closely that of Cu(+): Ag(+)-mediated dimerisation of the protein occurs, and distinct Ag(+)-bound species are formed at higher Ag(+) loadings. Cd(2+) also binds to CopZ, but exhibits significantly different behaviour. Cd(2+)-mediated dimerisation is only observed at low loadings, such that at 0.5 and one Cd(2+) per CopZ the protein is present mainly in a monomeric form; and multinuclear higher-order forms of Cd(2+)-CopZ are not observed. Competition binding studies reveal that Ag(+) binds with an affinity very similar to that of Cu(+), while Cd(2+) binding is significantly weaker. These data provide support for the proposal that CopZ may be involved in the detoxification of silver and cadmium, in addition to copper.
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31
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Orihuela R, Domènech J, Bofill R, You C, Mackay EA, Kägi JHR, Capdevila M, Atrian S. The metal-binding features of the recombinant mussel Mytilus edulis MT-10-IV metallothionein. J Biol Inorg Chem 2008; 13:801-12. [PMID: 18389296 DOI: 10.1007/s00775-008-0367-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 03/20/2008] [Indexed: 11/29/2022]
Abstract
In contrast with the paradigmatic mammalian metallothioneins (MTs), mollusc MT systems consist at least of a high-cadmium induced form, possibly involved in detoxification, and another isoform either constitutive or regulated by essential metals and probably associated with housekeeping metabolism. With the aim of providing a deeper characterization of the coordination features of a molluscan MT peptide of the latter kind, we have analyzed here the metal-binding abilities of the recombinant MeMT-10-IV isoform of Mytilus edulis (MeMT). Also, comparison with other MTs of this type has been undertaken. A synthetic complementary DNA was constructed, cloned and expressed into two Escherichia coli systems. Upon zinc coordination, MeMT folds in vivo into highly chiral and stable Zn(7) complexes, with an exceptional reluctance to fully substitute cadmium(II) and/or copper(I) for zinc(II). In vivo cadmium binding leads to homometallic Cd(7) complexes that structurally differ from any of the in vitro prepared Cd(7) complexes. Homometallic Cu-MeMT can only be obtained in vitro from Zn(7)-MeMT after a great molar excess of copper(I) has been added. In vivo, two different heterometallic Zn,Cu-MeMT complexes are recovered, which nicely correspond to two distinct stages of the in vitro zinc/copper replacement. These MeMT metal-binding features are consistent with a physiological role related to basal/housekeeping metal, mainly zinc, metabolism, and confirm the correspondence between the MeMT gene response pattern and the functional properties of the encoded protein.
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Affiliation(s)
- Rubén Orihuela
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
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Domènech J, Bofill R, Tinti A, Torreggiani A, Atrian S, Capdevila M. Comparative insight into the Zn(II)-, Cd(II)- and Cu(I)-binding features of the protozoan Tetrahymena pyriformis MT1 metallothionein. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:693-704. [DOI: 10.1016/j.bbapap.2008.01.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 01/03/2008] [Accepted: 01/07/2008] [Indexed: 11/29/2022]
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Dolderer B, Echner H, Beck A, Hartmann HJ, Weser U, Luchinat C, Del Bianco C. Coordination of three and four Cu(I) to the alpha- and beta-domain of vertebrate Zn-metallothionein-1, respectively, induces significant structural changes. FEBS J 2007; 274:2349-62. [PMID: 17403038 DOI: 10.1111/j.1742-4658.2007.05770.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Vertebrate metallothioneins are found to contain Zn(II) and variable amounts of Cu(I), in vivo, and are believed to be important for d10-metal control. To date, structural information is available for the Zn(II) and Cd(II) forms, but not for the Cu(I) or mixed metal forms. Cu(I) binding to metallothionein-1 has been investigated by circular dichroism, luminescence and 1H NMR using two synthetic fragments representing the alpha- and the beta-domain. The 1H NMR data and thus the structures of Zn4alpha metallothionein (MT)-1 and Zn3betaMT-1 were essentially the same as those already published for the corresponding domains of native Cd7MT-1. Cu(I) titration of the Zn(II)-reconstituted domains provided clear evidence of stable polypeptide folds of the three Cu(I)-containing alpha- and the four Cu(I)-containing beta-domains. The solution structures of these two species are grossly different from the structures of the starting Zn(II) complexes. Further addition of Cu(I) to the two single domains led to the loss of defined domain structures. Upon mixing of the separately prepared aqueous three and four Cu(I) loaded alpha- and beta-domains, no interaction was seen between the two species. There was neither any indication for a net transfer of Cu(I) between the two domains nor for the formation of one large single Cu(I) cluster involving both domains.
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Affiliation(s)
- Benedikt Dolderer
- Interfakultäres Institut für Biochemie, University of Tübingen, Germany
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Salgado MT, Bacher KL, Stillman MJ. Probing structural changes in the α and β domains of copper- and silver-substituted metallothionein by emission spectroscopy and electrospray ionization mass spectrometry. J Biol Inorg Chem 2006; 12:294-312. [PMID: 17086417 DOI: 10.1007/s00775-006-0187-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 10/06/2006] [Indexed: 10/24/2022]
Abstract
Steady-state emission spectra, excited-state lifetimes, kinetic data, and mass spectroscopic properties are reported for Ag(I)- and mixed Ag(I)/Cu(I)-substituted alpha and beta domains of recombinant human metallothionein (MT1a). Kinetic analysis of the changes in the Cu(I) emission spectra during the stepwise displacement of Cu(I) ions by Ag(I) at room temperature shows that the rate of displacement of Cu(I) is unexpectedly slow. Although the first Ag(I) added results in major changes in the Cu(I)-MT binding site, Cu(I) displacement by Ag(I) does not take place until the addition of the third Ag(I), and is completed by the addition of the seventh Ag(I). The emission from Ag(I) and mixed Cu(I)/Ag(I)-MT species at 77 K shows that the band maxima shift as a function of Ag(I) loading, which can be correlated with shifts in coordination geometry from trigonal to digonal. Two phosphorescence lifetimes were detected for the Ag(I)-substituted alpha and beta domains of MT, which are attributed to the presence of Ag(I) ions in two different environments. The lifetime of Ag(I)-substituted MT was found to be shorter when the Ag(I)-MT species were formed by Ag(I) additions to the Cu(I)-substituted alpha and beta fragments than when the Ag(I)-MT species were formed from the apo-alpha and apo-beta fragments, suggesting the formation of structurally different Ag(I)-MT clusters. Electrospray ionization mass spectrometric studies suggest the metallation reactions of Ag(I) with MT take place in a series of steps to form a series of Ag(I)-substituted MT species. Ag(I)-substituted MT species are not detected until past the addition of 3 mol equiv of Ag(I), suggesting that cluster formation begins only at this point, stabilizing the metallated species sufficiently to survive ionization.
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Affiliation(s)
- Maria T Salgado
- Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7, Canada
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Tío L, Villarreal L, Atrian S, Capdevila M. The Zn- and Cd-clusters of recombinant mammalian MT1 and MT4 metallothionein domains include sulfide ligands. Exp Biol Med (Maywood) 2006; 231:1522-7. [PMID: 17018875 DOI: 10.1177/153537020623100911] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Recombinant (E. coli ) synthesis of mammalian MT1 and MT4 domains as separate peptides in Zn(II) and Cd(II) enriched growth media has rendered metal complexes containing sulfide anions as additional ligands. The Cd preparations show higher sulfide content than the Zn preparations. Also, the betaMT1 and betaMT4 fragments exhibit higher sulfide/peptide ratios than the respective alpha fragments. Titration of Zn3-betaMT1 with Cd(II) followed by addition of several sodium sulfide equivalents shows that the Cd(II)-betaMT1 species can incorporate sulfide ligands in vitro, with a concomitant evolution of their UV-vis and CD fingerprints to those characteristic of the Cd-S2- chromophores. Current results have also provided full understanding of previous data collected by this group in the characterization of the Cd-betaMT1 preparations obtained from large-scale fermentor synthesis by allowing identification of at least 2S2- ligands per Cd-betaMT1 species. Furthermore, the results here presented have revealed that synthesis of betaMT4 in Cd-supplemented cultures yielded Cd,S(2-)-containing clusters instead of the proposed heterometallic Zn,Cd-betaMT4 complexes. Finally, a global evaluation of our results suggests that the higher the Cu-thionein character of a MT peptide, the higher is its tendency to harbor nonproteic ligands (i.e., sulfide anions) when building divalent metal clusters, especially Cd-MT complexes.
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Affiliation(s)
- Laura Tío
- Departament de Genètica, Universitat de Barcelona, 08028-Barcelona, Spain
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Capdevila M, Domènech J, Pagani A, Tío L, Villarreal L, Atrian S. Zn- and Cd-metallothionein recombinant species from the most diverse phyla may contain sulfide (S2-) ligands. Angew Chem Int Ed Engl 2006; 44:4618-22. [PMID: 15991200 DOI: 10.1002/anie.200501183] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Mercè Capdevila
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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Di Marco VB, Bombi GG. Electrospray mass spectrometry (ESI-MS) in the study of metal-ligand solution equilibria. MASS SPECTROMETRY REVIEWS 2006; 25:347-79. [PMID: 16369936 DOI: 10.1002/mas.20070] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In the 20 years, since the introduction of electrospray mass spectrometry (ESI-MS), the use of this technique in various fields of inorganic, organometallic, and analytical chemistry has been steadily increasing. In this study, the application of ESI-MS to the study of metal-ligand solution equilibria is reviewed (till 2004 included). In a first section, advantages and drawbacks of ESI-MS in this type of application are described. Subsequently, a list of ca. 300 studies is reported, in which ESI-MS was used to give number and stoichiometry of the species at equilibrium, or also to estimate their stability constants. All studies are classified according to the metal ions under examination. Other related applications, such as host-guest interactions and metal ion-protein binding studies, are briefly reviewed as well.
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Villarreal L, Tío L, Capdevila M, Atrian S. Comparative metal binding and genomic analysis of the avian (chicken) and mammalian metallothionein. FEBS J 2006; 273:523-35. [PMID: 16420476 DOI: 10.1111/j.1742-4658.2005.05086.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Chicken metallothionein (ckMT) is the paradigm for the study of metallothioneins (MTs) in the Aves class of vertebrates. Available literature data depict ckMT as a one-copy gene, encoding an MT protein highly similar to mammalian MT1. In contrast, the MT system in mammals consists of a four-member family exhibiting functional differentiation. This scenario prompted us to analyse the apparently distinct evolutionary patterns followed by MTs in birds and mammals, at both the functional and structural levels. Thus, in this work, the ckMT metal binding abilities towards Zn(II), Cd(II) and Cu(I) have been thoroughly revisited and then compared with those of the mammalian MT1 and MT4 isoforms, identified as zinc- and copper-thioneins, respectively. Interestingly, a new mechanism of MT dimerization is reported, on the basis of the coordinating capacity of the ckMT C-terminal histidine. Furthermore, an evolutionary study has been performed by means of in silico analyses of avian MT genes and proteins. The joint consideration of the functional and genomic data obtained questions the two features until now defining the avian MT system. Overall, in vivo and in vitro metal-binding results reveal that the Zn(II), Cd(II) and Cu(I) binding abilities of ckMT lay between those of mammalian MT1 and MT4, being closer to those of MT1 for the divalent metal ions but more similar to those of MT4 for Cu(I). This is consistent with a strong functional constraint operating on low-copy number genes that must cope with differentiating functional limitation. Finally, a second MT gene has been identified in silico in the chicken genome, ckMT2, exhibiting all the features to be considered an active coding region. The results presented here allow a new insight into the metal binding abilities of warm blooded vertebrate MTs and their evolutionary relationships.
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Affiliation(s)
- Laura Villarreal
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Domènech J, Mir G, Huguet G, Capdevila M, Molinas M, Atrian S. Plant metallothionein domains: functional insight into physiological metal binding and protein folding. Biochimie 2005; 88:583-93. [PMID: 16377055 DOI: 10.1016/j.biochi.2005.11.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Revised: 10/31/2005] [Accepted: 11/04/2005] [Indexed: 10/25/2022]
Abstract
Plant metallothioneins (MTs) differ from animal MTs by a peculiar sequence organization consisting of two short cysteine-rich terminal domains linked by a long cysteine-devoid spacer. The role of the plant MT domains in the protein structure and functionality is largely unknown. Here, we investigate the separate domain contribution to the in vivo binding of Zn and Cu and to confer metal tolerance to CUP1-null yeast cells of a plant type 2 MT (QsMT). For this purpose, we obtained three recombinant peptides that, respectively, correspond to the single N-terminal (N25) and C-terminal (C18) cysteine-rich domains of QsMT, and a chimera in which the spacer is replaced with a four-glycine bridge (N25-C18). The metal-peptide preparations recovered from Zn- or Cu-enriched cultures were characterized by ESI-MS, ICP-OES and CD and UV-vis spectroscopy and data compared to full length QsMT. Results are consistent with QsMT giving rise to homometallic Zn- or Cu-MT complexes according to a hairpin model in which the two Cys-rich domains interact to form a cluster. In this model the spacer region does not contribute to the metal coordination. However, our data from Zn-QsMT (but not from Cu-QsMT) support a fold of the spacer involving some interaction with the metal core. On the other hand, results from functional complementation assays in endogenous MT-defective yeast cells suggest that the spacer region may play a role in Cu-QsMT stability or subcellular localization. As a whole, our results provide the first insight into the structure/function relationship of plant MTs using the analysis of the separate domain abilities to bind physiological metals.
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Affiliation(s)
- Jordi Domènech
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
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Capdevila M, Domènech J, Pagani A, Tío L, Villarreal L, Atrian S. Zn- and Cd-Metallothionein Recombinant Species from the Most Diverse Phyla May Contain Sulfide (S2−) Ligands. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200501183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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41
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Bachechi F, Burini A, Galassi R, Rosa Pietroni B, Ricciutelli M. Electrospray mass spectrometry characterization of ionic silver(I) and gold(I) complexes of the ligand L=1-benzyl-2-imidazolyl-diphenylphosphine. Inorganica Chim Acta 2004. [DOI: 10.1016/j.ica.2004.06.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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42
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Leiva-Presa A, Capdevila M, Gonzàlez-Duarte P. Mercury(II) binding to metallothioneins. Variables governing the formation and structural features of the mammalian Hg-MT species. ACTA ACUST UNITED AC 2004; 271:4872-80. [PMID: 15606775 DOI: 10.1111/j.1432-1033.2004.04456.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
With the aim of extending our knowledge on the reaction pathways of Zn-metallothionein (MT) and apo-MT species in the presence of Hg(II), we monitored the titration of Zn7-MT, Zn4-alphaMT and Zn3-betaMT proteins, at pH 7 and 3, with either HgCl2 or Hg(ClO4)2 by CD and UV-vis spectroscopy. Detailed analysis of the optical data revealed that standard variables, such as the pH of the solution, the binding ability of the counter-ion (chloride or perchlorate), and the time elapsed between subsequent additions of Hg(II) to the protein, play a determinant role in the stoichiometry, stereochemistry and degree of folding of the Hg-MT species. Despite the fact that the effect of these variables is unquestionable, it is difficult to generalize. Overall, it can be concluded that the reaction conditions [pH, time elapsed between subsequent additions of Hg(II) to the protein] affect the structural properties more substantially than the stoichiometry of the Hg-MT species, and that the role of the counter-ion becomes particularly apparent on the structure of overloaded Hg-MT.
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Affiliation(s)
- Angels Leiva-Presa
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, Spain
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Cobine PA, McKay RT, Zangger K, Dameron CT, Armitage IM. Solution structure of Cu6 metallothionein from the fungus Neurospora crassa. ACTA ACUST UNITED AC 2004; 271:4213-21. [PMID: 15511227 DOI: 10.1111/j.1432-1033.2004.04361.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The 3D-solution structure of Neurospora crassa Cu(6)-metallothionein (NcMT) polypeptide backbone was determined using homonuclear, multidimensional (1)H-NMR spectroscopy. It represents a new metallothionein (MT) fold with a protein chain where the N-terminal half is left-handed and the C-terminal half right-handedly folded around a copper(I)-sulfur cluster. As seen with other MTs, the protein lacks definable secondary structural elements; however, the polypeptide fold is unique. The metal coordination and the cysteine spacing defines this unique fold. NcMT is only the second MT in the copper-bound form to be structurally characterized and the first containing the -CxCxxxxxCxC- motif. This motif is found in a variety of mammalian MTs and metalloregulatory proteins. The in vitro formation of the Cu(6)NcMT identical to the native Cu(6)NcMT was dependent upon the prior formation of the Zn(3)NcMT and its titration with Cu(I). The enhanced sensitivity and resolution of the 800 MHz (1)H-NMR spectral data permitted the 3D structure determination of the polypeptide backbone without the substitution and utilization of the NMR active spin 1/2 metals such as (113)Cd and (109)Ag. These restraints have been necessary to establish specific metal to cysteine restraints in 3D structural studies on this family of proteins when using lower field, less sensitive (1)H-NMR spectral data. The accuracy of the structure calculated without these constraints is, however, supported by the similarities of the 800 MHz structures of the alpha-domain of mouse MT1 compared to the one recalculated without metal-cysteine connectivities.
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Affiliation(s)
- Paul A Cobine
- Health Science Center, University of Utah, Salt Lake City, UT, USA
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Leiva-Presa A, Capdevila M, Cols N, Atrian S, González-Duarte P. Chemical foundation of the attenuation of methylmercury(II) cytotoxicity by metallothioneins. ACTA ACUST UNITED AC 2004; 271:1323-8. [PMID: 15030482 DOI: 10.1111/j.1432-1033.2004.04039.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
To elucidate the chemical interactions underlying the role of metallothioneins (MTs) in reducing the cytotoxicity caused by MeHg(II), we monitored in parallel by electronic absorption and CD spectroscopies the stepwise addition of MeHgCl stock solution to mammalian Zn(7)-MT1 and the isolated Zn(4)-alphaMT1 and Zn(3)-betaMT1 fragments. The incorporation of MeHg(+) into Zn(7)-MT and Zn(3)-betaMT entails total displacement of Zn(II) and unfolding of the protein. However, both features are only partial for Zn(4)-alphaMT. The different behavior observed for this fragment, whether isolated or constituting one of the two domains of Zn(7)-MT, indicates interdomain interactions in the whole protein. Overall, the binding properties of Zn(7)-MT, Zn(4)-alphaMT and Zn(3)-betaMT toward MeHg(+) are unprecedented. In addition, the sequestration of MeHg(+) by Zn(7)-MT and the concomitant release of Zn(II) are probably two of the main contributions in the detoxifying role of mammalian MT.
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Affiliation(s)
- Angels Leiva-Presa
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, Spain
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Tío L, Villarreal L, Atrian S, Capdevila M. Functional differentiation in the mammalian metallothionein gene family: metal binding features of mouse MT4 and comparison with its paralog MT1. J Biol Chem 2004; 279:24403-13. [PMID: 15033980 DOI: 10.1074/jbc.m401346200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This paper reports on the characterization of the metal binding abilities of mammalian MT4 and their comparison with those of the well known MT1. Heterologous Escherichia coli expression in cultures supplemented with zinc, cadmium, or copper was achieved for MT4 and for its separate alphaMT4 and betaMT4 domains as well as for MT1 and its alphaMT1 domain in cadmium-enriched medium. The in vivo conformed metal complexes and the in vitro substituted zinc/cadmium and zinc/copper MT4 aggregates were characterized. Biosynthesis of MT4 and betaMT4 in Cd(II)-supplemented medium revealed that these peptides failed to form the same homometallic species as MT1, thus appearing less effective for cadmium coordination. Conversely, the entire MT4 and both of its domains showed better Cu(I) binding properties than MT1, affording Cu(10)-MT4, Cu(5)-alphaMT4 and Cu(7)-betaMT4, stoichiometries that make the domain dependence toward Cu(I) clear. Overall results allow consideration of MT4 as a novel copper-thionein, made up of two copper-thionein domains, the first of this class reported in mammals, and by extension in vertebrates. Furthermore, the in silico protein sequence analyses corroborated the copper-thionein nature of the MT4 peptides. As a consequence, there is the suggestion of a possible physiological role played by MT4 related with copper requirements in epithelial differentiating tissues, where MT4 is expressed.
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Affiliation(s)
- Laura Tío
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Avd. Diagonal 645, 08028 Barcelona, Spain
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Palacios O, Polec-Pawlak K, Lobinski R, Capdevila M, González-Duarte P. Is Ag(I) an adequate probe for Cu(I) in structural copper-metallothionein studies? The binding features of Ag(I) to mammalian metallothionein 1. J Biol Inorg Chem 2003; 8:831-42. [PMID: 14505073 DOI: 10.1007/s00775-003-0481-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2003] [Accepted: 06/24/2003] [Indexed: 10/26/2022]
Abstract
The binding abilities of silver(I) to mammalian MT 1 have been studied and compared with those of copper(I), recently reported [Bofill et al. (2001) J Biol Inorg Chem 6:408-417], with the aim of analyzing the suitability of Ag(I) as a Cu(I) probe in Cu-MT studies. The Zn/Ag replacement in recombinant mouse Zn(7)-MT 1 and corresponding Zn(4)-alphaMT 1 and Zn(3)-betaMT 1 fragments, as well as the stepwise incorporation of Ag(I) to the corresponding apo-MTs, have been followed in parallel by various spectroscopic techniques including electronic absorption (UV-vis), circular dichroism (CD) and electrospray mass spectrometry coupled to capillary zone electrophoresis (CZE-ESI-MS). A comparative analysis of the sets of data obtained in the titration of Zn(7)-MT 1, Zn(4)-alphaMT 1 and Zn(3)-betaMT 1 with AgClO(4) at pH 7.5 and 2.5 has led to the reaction pathways followed during the incorporation of silver to these proteins under these specific conditions, disclosing unprecedented stoichiometries and structural features for the species formed. Thus, the Zn/Ag replacement in Zn(7)-MT 1 at pH 7.5 has revealed the subsequent formation of Ag(4)Zn(5)-MT, Ag(7)Zn(3)-MT, Ag(8)Zn(3)-MT, Ag(10)Zn(2)-MT, Ag(12)Zn(1)-MT, Ag(x)-MT, x=14-19, whose structure consists of two additive domains only if Zn(II) remains coordinated to the protein. A second structural role for Zn(II) has been deduced from the different folding found for the Ag(x)-MT species of the same stoichiometry formed at pH 7.5 or 2.5. Comparison of the binding features of Cu(I) and Ag(I) to the entire MT at pH 7.5 shows that, among all the micro(x)Zn(y)-MT (0<or= y<7) species found, only M(I)(4)Zn(5)-MT [(Zn(4))(alpha)(micro(4)Zn(1))(beta)] and M(I)(7)Zn(3)-MT [(micro(3)Zn(2))(alpha)(micro(4)Zn(1))(beta)], which form during the first stages of the Zn(II)/M(I) metal replacement, show comparable 3D structures; thus, they are the only species where Ag(I) ions can be predicted to be an adequate probe for Cu(I).
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Affiliation(s)
- Oscar Palacios
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Shen XC, Liang H, Guo JH, Song C, He XW, Yuan YZ. Studies on the interaction between Ag(+) and human serum albumin. J Inorg Biochem 2003; 95:124-30. [PMID: 12763656 DOI: 10.1016/s0162-0134(03)00094-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The interaction between Ag(+) and human serum albumin (HSA) has been intensively studied by means of equilibrium dialysis, ligand-to-metal charge transition (LMCT) bands, circular dichroism (CD) and Raman spectroscopy. Scatchard analysis of the results of equilibrium dialysis indicates the presence of two types of binding sites for Ag(+) on HSA, and the orders of magnitude of binding stability constants are found to be 10(5) and 10(4), respectively. During the binding process, a gradual increase in absorbance values of LMCT bands is observed with time-scanning UV absorption spectra, implying the Ag(I) centers are continually formed in HSA. The time-scanning CD spectra provide evidence that the binding of Ag(+) induces HSA to undergo a slow rearrangement of tertiary structure, and to change from the original conformation in the absence of Ag(+) (B-state) to conformation binding with Ag(+) (A-state). The rate constants and activation free energy of A-B transition are calculated. The Raman spectrum of Ag(I)-HSA system shows distinct vibration bands at 224 and 246 cm(-1) in the low-frequency region, which significantly reveal the formation of Ag-S and Ag-N bonds. In addition, the electrostatic interaction between Ag(+) and negatively charged oxygen is also detected with Raman spectroscopy.
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Affiliation(s)
- Xing-Can Shen
- Department of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, China
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The speciation of natural tissues by electrospray-mass spectrometry. II: Bioinduced ligands and environmental contaminants. Trends Analyt Chem 2003. [DOI: 10.1016/s0165-9936(03)00501-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Domenech J, Palacios O, Villarreal L, González-Duarte P, Capdevila M, Atrian S. MTO: the second member of a Drosophila dual copper-thionein system. FEBS Lett 2003; 533:72-8. [PMID: 12505162 DOI: 10.1016/s0014-5793(02)03754-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Drosophila MTO metal binding features were analyzed for comparison with MTN, the paralogous Drosophila metallothionein, and to classify MTO as either zinc- or copper-thionein. This was achieved by a combination of in vivo, in vitro and in silico methodologies. All the results unambiguously classified MTO as a second Drosophila copper-thionein, putting Drosophila forward as the only metazoan in which any zinc-thionein has still to be reported. Interestingly, experimental data only showed minor differences in the coordinative behavior of both MTs, but provided a characteristic spectroscopic fingerprint, revealing the possible binding of chloride anions in certain metal-MTO aggregates.
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Affiliation(s)
- J Domenech
- Departament de Genètica, Facultat de Biologia, Av. Diagonal 645, Universitat de Barcelona, E-08028, Barcelona, Spain
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Kihlken MA, Leech AP, Le Brun NE. Copper-mediated dimerization of CopZ, a predicted copper chaperone from Bacillus subtilis. Biochem J 2002; 368:729-39. [PMID: 12238948 PMCID: PMC1223043 DOI: 10.1042/bj20021036] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2002] [Revised: 09/03/2002] [Accepted: 09/19/2002] [Indexed: 12/22/2022]
Abstract
Understanding the metal-binding properties and solution states of metallo-chaperones is a key step in understanding how they function in metal ion transfer. Using spectroscopic, bioanalytical and biochemical methods, we have investigated the copper-binding properties and association states of the putative copper chaperone of Bacillus subtilis, CopZ, and a variant of the protein lacking the two cysteine residues of the MXCXXC copper-binding motif. We show that copper-free CopZ exists as a monomer, but that addition of copper(I) causes the protein to associate into homodimers. The nature of the copper(I)-CopZ complex is dependent on the level of copper loading, and we report the detection of three distinct forms, containing 0.5, 1.0 and 1.5 copper(I) ions per protein. The presence of excess dithiothreitol has a significant effect on copper(I) binding to CopZ, such that, in its presence, copper(I)-CopZ occurs mainly as a monomer species. Data for copper binding to the double-cysteine variant of CopZ are consistent with an essential role for these residues in tight copper binding in the wild-type protein. We conclude that the complex nature of copper(I) binding to CopZ may underpin mechanisms of protein-to-protein copper(I) transfer.
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Affiliation(s)
- Margaret A Kihlken
- Centre for Metalloprotein Spectroscopy and Biology, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK
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