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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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2
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Salim A, Chesnov S, Freisinger E. Metallation pathway of a plant metallothionein: Cicer arietinum MT2. J Inorg Biochem 2020; 210:111157. [PMID: 32622214 DOI: 10.1016/j.jinorgbio.2020.111157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 06/18/2020] [Accepted: 06/21/2020] [Indexed: 11/25/2022]
Abstract
The plant metallothionein 2 protein from Cicer arietinum (cicMT2) is a typical member of the plant MT subfamily p2 that is characterized by an N- and C-terminal cysteine- (Cys-)rich, metal binding sequence connected by a long cysteine-free linker region. cicMT2 coordinates up to five ZnII or CdII ions by its 14 cysteine thiolate groups forming a single metal-thiolate cluster. While MTs from other phyla are considerably well-studied, many details about plant MTs are missing. In this study the metallation pathway of cicMT2 is investigated using mass spectrometry. To evaluate the influence of the linker region as well as the interplay of the two Cys-rich stretches, the full-length cicMT2 protein as well as the individual Cys-rich domains with and without the linker region were analysed. Up to three CdII ions can be coordinated by the eight Cys residues of the N-terminal part and up to two CdII ions by the six Cys residues of the C-terminal sequence. However, no preferential binding to either of the two sequences is observed, which is in-line with the closely similar apparent binding constants of the individual domains obtained from competition reactions with the chelator 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid. The combination of limited proteolytic digestion, mass spectrometry, dynamic light scattering, size-exclusion chromatography, and 19F NMR spectroscopy enables us to draw conclusions about the overall protein-fold and the cluster formation process.
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Affiliation(s)
- Alma Salim
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | - Serge Chesnov
- University of Zurich/ETH Zurich, Functional Genomics Centre Zurich, Zurich, Switzerland
| | - Eva Freisinger
- Department of Chemistry, University of Zurich, Zurich, Switzerland.
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3
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Saad RB, Hsouna AB, Saibi W, Hamed KB, Brini F, Ghneim-Herrera T. A stress-associated protein, LmSAP, from the halophyte Lobularia maritima provides tolerance to heavy metals in tobacco through increased ROS scavenging and metal detoxification processes. JOURNAL OF PLANT PHYSIOLOGY 2018; 231:234-243. [PMID: 30312968 DOI: 10.1016/j.jplph.2018.09.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 06/08/2023]
Abstract
Agricultural soil pollution by heavy metals is a severe global ecological problem. We recently showed that overexpression of LmSAP, a member of the stress-associated protein (SAP) gene family isolated from Lobularia maritima, in transgenic tobacco led to enhanced tolerance to abiotic stress. In this study, we characterised the response of LmSAP transgenic tobacco plants to metal stresses (cadmium (Cd), copper (Cu), manganese (Mn), and zinc (Zn)). In L. maritima, LmSAP expression increased after 12 h of treatment with these metals, suggesting its involvement in the plant response to heavy metal stress. LmSAP transgenic tobacco plants subjected to these stress conditions were healthy, experienced higher seedling survival rates, and had longer roots than non-transgenic plants (NT). However, they exhibited higher tolerance towards cadmium and manganese than towards copper and zinc. LmSAP-overexpressing tobacco seedlings accumulated more cadmium, copper, and manganese compared with NT plants, but displayed markedly decreased hydrogen peroxide (H2O2) and lipid peroxidation levels after metal treatment. Activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were significantly higher in transgenic plants than in NT plants after exposure to metal stress. LmSAP overexpression also enhanced the transcription of several genes encoding metallothioneins (Met1, Met2, Met3, Met4, and Met5), a copper transport protein CCH, a Cys and His-rich domain-containing protein RAR1 (Rar1), and a ubiquitin-like protein 5 (PUB1), which are involved in metal tolerance in tobacco. Our findings indicate that LmSAP overexpression in tobacco enhanced tolerance to heavy metal stress by protecting the plant cells against oxidative stress, scavenging reactive oxygen species (ROS), and decreasing the intracellular concentration of free heavy metals through its effect on metal-binding proteins in the cytosol.
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Affiliation(s)
- Rania Ben Saad
- Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax, University of Sfax, B.P "1177", 3018, Sfax, Tunisia
| | - Anis Ben Hsouna
- Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax, University of Sfax, B.P "1177", 3018, Sfax, Tunisia; Departments of Life Sciences, Faculty of Sciences of Gafsa, Zarroug, 2112, Gafsa, Tunisia
| | - Walid Saibi
- Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax, University of Sfax, B.P "1177", 3018, Sfax, Tunisia
| | - Karim Ben Hamed
- Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologie de Borj Cedria, BP 901, Hammam Lif, 2050, Tunisia
| | - Faical Brini
- Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax, University of Sfax, B.P "1177", 3018, Sfax, Tunisia
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4
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Mierek-Adamska A, Dąbrowska GB, Blindauer CA. The type 4 metallothionein from Brassica napus seeds folds in a metal-dependent fashion and favours zinc over other metals. Metallomics 2018; 10:1430-1443. [DOI: 10.1039/c8mt00161h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rapeseed MT4 only folds properly in the presence of Zn2+ and thus may serve as a selectivity filter for metal accumulation in plant embryos.
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Affiliation(s)
- Agnieszka Mierek-Adamska
- Department of Genetics
- Faculty of Biology and Environmental Protection
- Nicolaus Copernicus University
- 87-100 Toruń
- Poland
| | - Grażyna B. Dąbrowska
- Department of Genetics
- Faculty of Biology and Environmental Protection
- Nicolaus Copernicus University
- 87-100 Toruń
- Poland
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5
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Ziller A, Yadav RK, Capdevila M, Reddy MS, Vallon L, Marmeisse R, Atrian S, Palacios Ò, Fraissinet-Tachet L. Metagenomics analysis reveals a new metallothionein family: Sequence and metal-binding features of new environmental cysteine-rich proteins. J Inorg Biochem 2016; 167:1-11. [PMID: 27886631 DOI: 10.1016/j.jinorgbio.2016.11.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/28/2016] [Accepted: 11/11/2016] [Indexed: 11/18/2022]
Abstract
Metallothioneins are cysteine-rich proteins, which function as (i) metal carriers in basal cell metabolism and (ii) protective metal chelators in conditions of metal excess. Metallothioneins have been characterized from different eukaryotic model and cultivable species. Presently, they are categorized in 15 families but evolutionary relationships between these metallothionein families remain unresolved. Several cysteine-rich protein encoding genes that conferred Cd-tolerance in Cd-sensitive yeast mutants have previously been isolated from soil eukaryotic metatranscriptomes. They were called CRPs for "cysteine-rich proteins". These proteins, of unknown taxonomic origins, share conserved cysteine motifs and could be considered as metallothioneins. In the present work, we analyzed these CRPs with respect to their amino acid sequence features and their metal-binding abilities towards Cd, Zn and Cu metal ions. Sequence analysis revealed that they share common features with different known metallothionein families, but also exhibit unique specific features. Noticeably, CRPs display two separate cysteine-rich domains which, when expressed separately in yeast, confer Cd-tolerance. The N-terminal domain contains some conserved atypical Cys motifs, such as one CCC and two CXCC ones. Five CRPs were expressed and purified as recombinant proteins and their metal-binding characteristics were studied. All these CRPs chelated Cd(II), Zn(II) and Cu(I), although displaying a better capacity for Zn(II) coordination. All CRPs are able to confer Cd-tolerance, and four of them confer Zn-tolerance in the Zn-sensitive zrc1Δ yeast mutant. We designated these CRPs as environmental metallothioneins belonging to a new formerly undescribed metallothionein family.
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Affiliation(s)
- Antoine Ziller
- Microbial Ecology, CNRS UMR 5557, INRA UMR 1418, Université Lyon 1, Université de Lyon, F-69622 Villeurbanne, France
| | - Rajiv Kumar Yadav
- Microbial Ecology, CNRS UMR 5557, INRA UMR 1418, Université Lyon 1, Université de Lyon, F-69622 Villeurbanne, France
| | - Mercè Capdevila
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Barcelona, Spain
| | | | - Laurent Vallon
- Microbial Ecology, CNRS UMR 5557, INRA UMR 1418, Université Lyon 1, Université de Lyon, F-69622 Villeurbanne, France
| | - Roland Marmeisse
- Microbial Ecology, CNRS UMR 5557, INRA UMR 1418, Université Lyon 1, Université de Lyon, F-69622 Villeurbanne, France
| | - Silvia Atrian
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, E-08028 Barcelona, Spain
| | - Òscar Palacios
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Laurence Fraissinet-Tachet
- Microbial Ecology, CNRS UMR 5557, INRA UMR 1418, Université Lyon 1, Université de Lyon, F-69622 Villeurbanne, France.
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6
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Gil-Moreno S, Jiménez-Martí E, Palacios Ò, Zerbe O, Dallinger R, Capdevila M, Atrian S. Does Variation of the Inter-Domain Linker Sequence Modulate the Metal Binding Behaviour of Helix pomatia Cd-Metallothionein? Int J Mol Sci 2015; 17:E6. [PMID: 26703589 PMCID: PMC4730253 DOI: 10.3390/ijms17010006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 12/11/2015] [Accepted: 12/14/2015] [Indexed: 11/16/2022] Open
Abstract
Snail metallothioneins (MTs) constitute an ideal model to study structure/function relationships in these metal-binding polypeptides. Helix pomatia harbours three MT isoforms: the highly specific CdMT and CuMT, and an unspecific Cd/CuMT, which represent paralogous proteins with extremely different metal binding preferences while sharing high sequence similarity. Preceding work allowed assessing that, although, the Cys residues are responsible for metal ion coordination, metal specificity or preference is achieved by diversification of the amino acids interspersed between them. The metal-specific MT polypeptides fold into unique, energetically-optimized complexes of defined metal content, when binding their cognate metal ions, while they produce a mixture of complexes, none of them representing a clear energy minimum, with non-cognate metal ions. Another critical, and so far mostly unexplored, region is the stretch linking the individual MT domains, each of which represents an independent metal cluster. In this work, we have designed and analyzed two HpCdMT constructs with substituted linker segments, and determined their coordination behavior when exposed to both cognate and non-cognate metal ions. Results unequivocally show that neither length nor composition of the inter-domain linker alter the features of the Zn(II)- and Cd(II)-complexes, but surprisingly that they influence their ability to bind Cu(I), the non-cognate metal ion.
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Affiliation(s)
- Selene Gil-Moreno
- 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.
| | - Òscar Palacios
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain.
| | - Oliver Zerbe
- Institute of Organic Chemistry, University of Zurich, 8057 Zurich, Switzerland.
| | - Reinhard Dallinger
- Institute of Zoology, 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.
| | - Sílvia Atrian
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, E-08028 Barcelona, Spain.
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7
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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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Sunflower metallothionein family characterisation. Study of the Zn(II)- and Cd(II)-binding abilities of the HaMT1 and HaMT2 isoforms. J Inorg Biochem 2015; 148:35-48. [PMID: 25770010 DOI: 10.1016/j.jinorgbio.2015.02.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/21/2015] [Accepted: 02/22/2015] [Indexed: 11/21/2022]
Abstract
Plant metallothioneins (MTs) constitute a family of small Cys-rich proteins capable of coordinating metal ions, significantly differing from microbial and animal MTs. They are divided into four subfamilies depending on the Cys pattern in their sequence. In this work, the MT system of the sunflower plant (Helianthus annuus) has been defined, with ten genes coding for MTs (HaMT) belonging to the four plant MT subfamilies; three HaMT1, four HaMT2, one HaMT3 and two HaMT4 isoforms. The gene expression pattern and capacity to confer metal resistance to yeast cells have been analysed for at least one member of each subfamily. The divalent metal ion-binding abilities of HaMT1-2 and HaMT2-1 (the isoforms encoded by the most abundantly expressed HaMT1 and HaMT2 isogenes) have been characterised, as HaMT3 and HaMT4 were previously studied. Those isoforms constitute an optimum material to study the effect of Cys number variability on their coordination abilities, as they exhibit additional Cys residues regarding the canonical Cys pattern of each subfamily. Our results show that the variation in the number of Cys does not drastically modify their M(II)-binding abilities, but instead modulates the degree of heterogeneity of the corresponding recombinant syntheses. Significantly, the Zn(II)-HaMT1 complexes were highly susceptible to proteolytic cleavage. The recombinant Cd-MT preparations of both isoforms exhibit significant acid-labile sulphide content-Cd6S8 or Cd7S7 species. Overall results suggest that HaMT2-1 is probably associated with Cd(II) detoxification, in contrast to HaMT1-2, which may be more related to physiological functions, such as metal ion transport and delivery.
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9
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Tomas M, Pagani MA, Andreo CS, Capdevila M, Bofill R, Atrian S. His-containing plant metallothioneins: comparative study of divalent metal-ion binding by plant MT3 and MT4 isoforms. J Biol Inorg Chem 2014; 19:1149-64. [PMID: 24951240 DOI: 10.1007/s00775-014-1170-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 05/31/2014] [Indexed: 11/30/2022]
Abstract
Metallothioneins (MTs) are a superfamily of Cys-rich, low-molecular weight metalloproteins that bind heavy metal ions. These cytosolic metallopeptides, which exist in most living organisms, are thought to be involved in metal homeostasis, metal detoxification, and oxidative stress protection. In this work, we characterise the Zn(II)- and Cd(II)-binding abilities of plant type 3 and type 4 MTs identified in soybean and sunflower, both of them being His-containing peptides. The recombinant metal-MT complexes synthesised in Zn(II) or Cd(II)-enriched Escherichia coli cultures have been analysed by ESI-MS, and CD, ICP-AES, and UV spectroscopies. His-to-Ala type 3 MT mutants have also been constructed and synthesised for the study of the role of His in divalent metal ion coordination. The results show comparable divalent metal-binding capacities for the MTs of type 3, and suggest, for the first time, the participation of their conserved C-term His residues in metal binding. Interesting features for the Zn(II)-binding abilities of type 4 MTs are also reported, as their variable His content may be considered crucial for their biological performance.
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Affiliation(s)
- Mireia Tomas
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08093, Barcelona, Spain
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10
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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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11
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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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12
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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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13
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Schiller M, Hegelund JN, Pedas P, Kichey T, Laursen KH, Husted S, Schjoerring JK. Barley metallothioneins differ in ontogenetic pattern and response to metals. PLANT, CELL & ENVIRONMENT 2014; 37:353-367. [PMID: 23808399 DOI: 10.1111/pce.12158] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 06/12/2013] [Accepted: 06/20/2013] [Indexed: 06/02/2023]
Abstract
The barley genome encodes a family of 10 metallothioneins (MTs) that have not previously been subject to extensive gene expression profiling. We show here that expression of MT1a, MT2b1, MT2b2 and MT3 in barley leaves increased more than 50-fold during the first 10 d after germination. Concurrently, the root-specific gene MT1b1 was 1000-fold up-regulated. Immunolocalizations provided the first evidence for accumulation of MT1a and MT2a proteins in planta, with correlation to transcript levels. In developing grains, MT2a and MT4 expression increased 4- and 300-fold over a 28-day-period after pollination. However, among the MT grain transcripts MT2c was the most abundant, whereas MT4 was the least abundant. Excess Cu up-regulated three out of the six MTs expressed in leaves of young barley plants. In contrast, most MTs were down-regulated by excess Zn or Cd. Zn starvation led to up-regulation of MT1a, whereas Cu starvation up-regulated MT2a, which has two copper-responsive elements in the promoter. Arabidopsis lines constitutively overexpressing barley MT2a showed increased sensitivity to excess Cd and Zn but no Cu-induced response. We suggest that barley MTs are differentially involved in intracellular homeostasis of essential metal ions and that a subset of barley MTs is specifically involved in Cu detoxification.
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Affiliation(s)
- Michaela Schiller
- Plant and Soil Science Section, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 40 Thorvaldsensvej, DK-1871, Frederiksberg C, Copenhagen, Denmark
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14
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Mudalkar S, Golla R, Sengupta D, Ghatty S, Reddy AR. Molecular cloning and characterisation of metallothionein type 2a gene from Jatropha curcas L., a promising biofuel plant. Mol Biol Rep 2013; 41:113-24. [DOI: 10.1007/s11033-013-2843-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 10/26/2013] [Indexed: 11/28/2022]
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15
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Heterologous expression and metal-binding characterization of a type 1 metallothionein isoform (OsMTI-1b) from rice (Oryza sativa). Protein J 2013; 32:131-7. [PMID: 23385446 DOI: 10.1007/s10930-013-9469-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Metallothioneins (MTs) are ubiquitous, low molecular mass and cysteine-rich proteins that play important roles in maintaining intracellular metal homeostasis, eliminating metal toxification and protecting the cells against oxidative damages. MTs are able to bind metal ions through the thiol groups of their cysteine residues. Plants have several MT isoforms which are classified into four types based on the arrangement of cysteine residues. In the present study, a rice (Oryza sativa) gene encoding type 1 MT isoform, OsMTI-1b, was inserted in vector pET41a and overexpressed in Escherichia coli as carboxy-terminal extensions of glutathione-S-transferase (GST). The recombinant protein GST-OsMTI-1b was purified using affinity chromatography and its ability to bind with Ni(2+), Cd(2+), Zn(2+) and Cu(2+) ions was analyzed. The results demonstrated that this isoform has ability to bind Ni(2+), Cd(2+) and Zn(2+) ions in vitro, whereas it has no substantial ability to bind Cu(2+) ions. From competitive reaction with 5,5'-dithiobis(2-nitrobenzoic acid), DTNB, the affinity of metal ions for recombinant form of GST-OsMTI-1b was as follows: Ni(2+)/Cd(2+) > Zn(2+) > Cu(2+).
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16
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Non-enzymatic modifications in metallothioneins connected to lipid membrane damages: structural and biomimetic studies under reductive radical stress. J Proteomics 2013; 92:204-15. [PMID: 23542714 DOI: 10.1016/j.jprot.2013.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 02/08/2013] [Accepted: 02/10/2013] [Indexed: 11/20/2022]
Abstract
UNLABELLED Metallothioneins (MTs) are small cysteine-rich proteins with the ability to coordinate heavy metal atoms through metal-thiolate bonds, which are widely distributed among the animal and plant kingdoms. Multifunctional roles for MTs have been proposed, including their ability to scavenger various radicals and reactive oxygen species. In the present article we summarize available information of four MT polypeptides from different organisms, forming metal complexes with Zn(II), Cd(II) or Cu (I) ions. Non-enzymatic modifications of MTs under ionizing radiations and their consequences on the lipidic membrane compartment were studied by Raman spectroscopy and a biomimetic model, respectively. The latter is based on liposome technology and allows to measure the trans unsaturated fatty acid content as a result of reductive radical stress on MTs. BIOLOGICAL SIGNIFICANCE The effect of radical stress on the cell metabolism and functions is a very active field of research connecting various disciplines in life sciences. In this contest tandem radical damage has been the subject of recent investigations that pointed out its harmfulness in the general scenario of establishing the consequences of radical stress. By using biomimetic models of tandem damage we have for the first time tested the capability of metallothioneins (MTs), small metalloproteins rich of Cys residues, to damage another cell compartment like lipid membranes when they are undergone to reductive radical stress. The connection of MT reactivity with membrane lipid transformation can give a contribution to the puzzling context of radical stress occurring to biomolecules and the role as biological signaling. To this purpose, MT polypeptides from different organisms, exhibiting different sequence peculiarities, have been analyzed here. The spectroscopic analysis of these systems has allowed to identify modifications affecting metal-thiolate clusters, cystines, and Met residues, acting as efficient interceptors of reducing radical species. The chemical mechanism involving sulfur-containing moieties under reductive conditions discloses new scenarios that bring to the loss of sulfur-centered radicals by desulfurization reactions that change the natural sequences of MTs. Ala is a genetically coded amino acid, therefore the mutation of Cys to Ala occurring to a sequence by the radical process so far discussed, corresponds to a post-translational modification. Research on such mutation connected also to a free radical stress will be important to contribute for a complete picture of the degeneration associated to diseases and aging. Analogously, the Met to Aba mutation occurring after reductive stress transforms a natural amino acid into a natural, non-genetically-coded congener. Aba corresponds to a homologation of the alkyl chains normally present in genetically codified amino acids, such as methyl (in Ala) and isopropyl (in Leu), with an ethyl unit. Based on alkyl substitution, this modification can therefore be studied in order to understand its general consequences on the structure-activity relationships in proteins and, in particular, on molecular interactions. This article is part of a Special issue entitled: Posttranslational Protein modifications in biology and Medicine.
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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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Huber T, Freisinger E. Sulfide ions as modulators of metal–thiolate cluster size in a plant metallothionein. Dalton Trans 2013; 42:8878-89. [DOI: 10.1039/c3dt32438a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Leszczyszyn OI, Imam HT, Blindauer CA. Diversity and distribution of plant metallothioneins: a review of structure, properties and functions. Metallomics 2013; 5:1146-69. [DOI: 10.1039/c3mt00072a] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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20
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Wan X, Freisinger E. Incorporation of Sulfide Ions into the Cadmium(II) Thiolate Cluster of Cicer arietinum Metallothionein2. Inorg Chem 2012; 52:785-92. [DOI: 10.1021/ic301907j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiaoqiong Wan
- Institute of Inorganic
Chemistry, University of Zurich, 8057 Zurich, Switzerland
- Key Laboratory of Arable Land
Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Eva Freisinger
- Institute of Inorganic
Chemistry, University of Zurich, 8057 Zurich, Switzerland
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Pagani MA, Tomas M, Carrillo J, Bofill R, Capdevila M, Atrian S, Andreo CS. The response of the different soybean metallothionein isoforms to cadmium intoxication. J Inorg Biochem 2012; 117:306-15. [PMID: 23073037 DOI: 10.1016/j.jinorgbio.2012.08.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 08/29/2012] [Accepted: 08/29/2012] [Indexed: 10/27/2022]
Abstract
Cadmium is a highly toxic heavy metal for both plants and animals. The presence of Cd in agricultural soils is of major concern regarding its entry into the food chain, since Cd compounds are readily taken up by plants, and accumulated in edible parts due to their high solubility. In this study, we first demonstrate the high capacity for Cd concentration of soybean grains. Consequently, we considered the study and characterization of the molecular determinants of Cd accumulation -such as metallothioneins (MT)- to be of major practical importance. We report here the first characterization of the soybean MT system, with the identification of nine genes (one of which is a truncated pseudogene), belonging to the four plant MT types. The most highly expressed of each type was chosen for further function analysis. All of them are expressed at high levels in soybean tissues: GmMT1, GmMT2 and GmMT3 in roots, shoots and seeds, and GmMT4 only in seeds. The corresponding recombinant soybean MTs, synthesized in Escherichia coli cells cultured in metal supplemented media, exhibit greater cadmium than zinc binding capacity. These results suggest a definite role of GmMTs in Cd(II) accumulation as one of the main responses of soybean to an overload of this metal.
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Affiliation(s)
- M A Pagani
- Centro de Estudios Fotosintéticos y Bioquímicos, CONICET, Suipacha 531, 2000 Rosario, Argentina.
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22
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Gautam N, Verma PK, Verma S, Tripathi RD, Trivedi PK, Adhikari B, Chakrabarty D. Genome-wide identification of rice class I metallothionein gene: tissue expression patterns and induction in response to heavy metal stress. Funct Integr Genomics 2012; 12:635-47. [PMID: 23053198 DOI: 10.1007/s10142-012-0297-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 09/03/2012] [Accepted: 09/24/2012] [Indexed: 01/11/2023]
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23
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Fernandez LR, Vandenbussche G, Roosens N, Govaerts C, Goormaghtigh E, Verbruggen N. Metal binding properties and structure of a type III metallothionein from the metal hyperaccumulator plant Noccaea caerulescens. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:1016-23. [DOI: 10.1016/j.bbapap.2012.05.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 05/07/2012] [Accepted: 05/25/2012] [Indexed: 11/30/2022]
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24
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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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25
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Chaturvedi AK, Mishra A, Tiwari V, Jha B. Cloning and transcript analysis of type 2 metallothionein gene (SbMT-2) from extreme halophyte Salicornia brachiata and its heterologous expression in E. coli. Gene 2012; 499:280-7. [DOI: 10.1016/j.gene.2012.03.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 03/01/2012] [Accepted: 03/01/2012] [Indexed: 11/16/2022]
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26
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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: 21] [Impact Index Per Article: 1.6] [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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27
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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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28
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Hassinen VH, Tervahauta AI, Schat H, Kärenlampi SO. Plant metallothioneins--metal chelators with ROS scavenging activity? PLANT BIOLOGY (STUTTGART, GERMANY) 2011; 13:225-32. [PMID: 21309968 DOI: 10.1111/j.1438-8677.2010.00398.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Metallothioneins (MTs) are ubiquitous cysteine-rich proteins present in plants, animals, fungi and cyanobacteria. In plants, MTs are suggested to be involved in metal tolerance or homeostasis, as they are able to bind metal ions through the thiol groups of their cysteine residues. Recent reports show that MTs are also involved in the scavenging of reactive oxygen species (ROS). The interplay between these roles is not entirely clear. Plants have many MT isoforms with overlapping expression patterns, and no specific role for any of them has been assigned. This review is focused on recent findings on plant MTs.
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Affiliation(s)
- V H Hassinen
- Department of Biosciences, University of Eastern Finland, Kuopio, Finland
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29
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Nikolić DB, Samardzić JT, Bratić AM, Radin IP, Gavrilović SP, Rausch T, Maksimović VR. Buckwheat (Fagopyrum esculentum Moench) FeMT3 gene in heavy metal stress: protective role of the protein and inducibility of the promoter region under Cu(2+) and Cd(2+) treatments. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:3488-94. [PMID: 20187605 DOI: 10.1021/jf904483a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The protective role in vivo of buckwheat metallothionein type 3 (FeMT3) during metal stress and the responsiveness of its promoter to metal ions were examined. Increased tolerance to heavy metals of FeMT3 producing Escherichia coli and cup1(Delta) yeast cells was detected. The defensive ability of buckwheat MT3 during Cd and Cu stresses was also demonstrated in Nicotiana debneyii leaves transiently expressing FeMT3. In contrast to phytochelatins, the cytoplasmatic localization of FeMT3 was not altered under heavy metal stress. Functional analysis of the corresponding promoter region revealed extremely high inducibility upon Cu(2+) and Cd(2+) treatments. The confirmed defense ability of FeMT3 protein in vivo and the great responsiveness of its promoter during heavy metal exposure make this gene a suitable candidate for biotechnological applications.
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Affiliation(s)
- Dragana B Nikolić
- Laboratory for Plant Molecular Biology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, Belgrade, Serbia.
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30
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Torreggiani A, Tinti A. Raman spectroscopy a promising technique for investigations of metallothioneins. Metallomics 2010; 2:246-60. [DOI: 10.1039/b922526a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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31
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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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32
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Torreggiani A, Domènech J, Orihuela R, Ferreri C, Atrian S, Capdevila M, Chatgilialoglu C. Zinc and Cadmium Complexes of a Plant Metallothionein under Radical Stress: Desulfurisation Reactions Associated with the Formation oftrans-Lipids in Model Membranes. Chemistry 2009; 15:6015-24. [PMID: 19418517 DOI: 10.1002/chem.200802533] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Armida Torreggiani
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, 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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34
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Wan X, Freisinger E. The plant metallothionein 2 from Cicer arietinum forms a single metal–thiolate cluster. Metallomics 2009; 1:489-500. [DOI: 10.1039/b906428a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Hassinen VH, Tuomainen M, Peräniemi S, Schat H, Kärenlampi SO, Tervahauta AI. Metallothioneins 2 and 3 contribute to the metal-adapted phenotype but are not directly linked to Zn accumulation in the metal hyperaccumulator, Thlaspi caerulescens. JOURNAL OF EXPERIMENTAL BOTANY 2008; 60:187-96. [PMID: 19033549 PMCID: PMC3071770 DOI: 10.1093/jxb/ern287] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 10/14/2008] [Accepted: 10/15/2008] [Indexed: 05/04/2023]
Abstract
To study the role of metallothioneins (MTs) in Zn accumulation, the expression of TcMT2a, TcMT2b, and TcMT3 was analysed in three accessions and 15 F(3) families of two inter-accession crosses of the Cd/Zn hyperaccumulator Thlaspi caerulescens, with different degrees of Zn accumulation. The highest expression levels were found in the shoots of a superior metal-accumulating calamine accession from St Laurent le Minier, with >10-fold TcMT3 expression compared with another calamine accession and a non-metallicolous accession. Moreover, F(3) sibling lines from the inter-accession crosses that harboured the MT2a or MT3 allele from St Laurent le Minier had higher expression levels. However, there was no co-segregation of TcMT2a or TcMT3 expression and Zn accumulation. To examine the functions of TcMTs in plants, TcMT2a and TcMT3 were ectopically expressed in Arabidopsis. The transformant lines had reduced root length in control medium but not at high metal concentrations, suggesting that the ectopically expressed proteins interfered with the physiological availability of essential metals under limited supply. The Arabidopsis transformant lines did not show increased tolerance to Cd, Cu, or Zn, nor increased Cd or Zn accumulation. Immunohistochemical analysis indicated that in roots, MT2 protein is localized in the epidermis and root hairs of both T. caerulescens and Arabidopsis thaliana. The results suggest that TcMT2a, TcMT2b, and TcMT3 are not primarily involved in Zn accumulation as such. However, the elevated expression levels in the metallicolous accessions suggests that they do contribute to the metal-adapted phenotype, possibly through improving Cu homeostasis at high Zn and Cd body burdens. Alternatively, they might function as hypostatic enhancers of Zn or Cd tolerance.
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Affiliation(s)
- V H Hassinen
- Department of Biosciences, University of Kuopio, Kuopio, Finland.
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36
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Torreggiani A, Domènech J, Atrian S, Capdevila M, Tinti A. Raman study of in vivo synthesized Zn(II)-metallothionein complexes: Structural insight into metal clusters and protein folding. Biopolymers 2008; 89:1114-24. [DOI: 10.1002/bip.21063] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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37
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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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Freisinger E. Plant MTs—long neglected members of the metallothionein superfamily. Dalton Trans 2008:6663-75. [DOI: 10.1039/b809789e] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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