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Effects of SDS on the activity and conformation of protein tyrosine phosphatase from thermus thermophilus HB27. Sci Rep 2020; 10:3195. [PMID: 32081966 PMCID: PMC7035334 DOI: 10.1038/s41598-020-60263-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 02/03/2020] [Indexed: 11/20/2022] Open
Abstract
Deciphering the activity-conformation relationship of PTPase is of great interest to understand how PTPase activity is determined by its conformation. Here we studied the activity and conformational transitions of PTPase from thermus thermophilus HB27 in the presence of sodium dodecyl sulfate (SDS). Activity assays showed the inactivation of PTPase induced by SDS was in a concentration-dependent manner. Fluorescence and circular dichroism spectra suggested SDS induced significant conformational transitions of PTPase, which resulted in the inactivation of PTPase, and the changes of α-helical structure and tertiary structure of PTPase. Structural analysis revealed a number of hydrophobic and charged residues around the active sites of PTPase may be involved in the hydrophobic and ionic bonds interactions of PTPase and SDS, which are suggested to be the major driving force to result in PTPase inactivation and conformational transitions induced by SDS. Our results suggested the hydrophobic and charged residues around the active sites were essential for the activity and conformation of PTPase. Our study promotes a better understanding of the activity and conformation of PTPase.
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Metallothionein from Wild Populations of the African Catfish Clarias gariepinus: From Sequence, Protein Expression and Metal Binding Properties to Transcriptional Biomarker of Metal Pollution. Int J Mol Sci 2017; 18:ijms18071548. [PMID: 28718783 PMCID: PMC5536036 DOI: 10.3390/ijms18071548] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/03/2017] [Accepted: 07/13/2017] [Indexed: 11/25/2022] Open
Abstract
Anthropogenic pollution with heavy metals is an on-going concern throughout the world, and methods to monitor release and impact of heavy metals are of high importance. With a view to probe its suitability as molecular biomarker of metal pollution, this study has determined a coding sequence for metallothionein of the African sharptooth catfish Clarias gariepinus. The gene product was recombinantly expressed in Escherichia coli in presence of Zn(II), Cd(II), or Cu, and characterised by Electrospray Ionisation Mass Spectrometry and elemental analysis. C. gariepinus MT displays typical features of fish MTs, including 20 conserved cysteines, and seven bound divalent cations (Zn(II) or Cd(II)) when saturated. Livers from wild C. gariepinus fish collected in all three seasons from four different sites on the Kafue River of Zambia were analysed for their metal contents and for MT expression levels by quantitative PCR. Significant correlations were found between Zn and Cu levels and MT expression in livers, with MT expression clearly highest at the most polluted site, Chililabombwe, which is situated in the Copperbelt region. Based on our findings, hepatic expression of MT from C. gariepinus may be further developed as a major molecular biomarker of heavy metal pollution resulting from mining activities in this region.
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De Luca V, Del Prete S, Carginale V, Vullo D, Supuran CT, Capasso C. Cloning, characterization and anion inhibition studies of a γ-carbonic anhydrase from the Antarctic cyanobacterium Nostoc commune. Bioorg Med Chem Lett 2015; 25:4970-4975. [DOI: 10.1016/j.bmcl.2015.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 02/26/2015] [Accepted: 03/02/2015] [Indexed: 10/23/2022]
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De Luca V, Del Prete S, Vullo D, Carginale V, Di Fonzo P, Osman SM, AlOthman Z, Supuran CT, Capasso C. Expression and characterization of a recombinant psychrophilic γ-carbonic anhydrase (NcoCA) identified in the genome of the Antarctic cyanobacteria belonging to the genus Nostoc. J Enzyme Inhib Med Chem 2015. [DOI: 10.3109/14756366.2015.1069289] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
| | - Sonia Del Prete
- Istituto di Bioscienze e Biorisorse, CNR, Napoli, Italy,
- Laboratorio di Chimica Bioinorganica, Dipartimento Di Chimica, Polo Scientifico, Università degli Studi di Firenze, Sesto Fiorentino, Florence, Italy,
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Polo Scientifico, Sesto Fiorentino, Florence, Italy, and
| | - Daniela Vullo
- Laboratorio di Chimica Bioinorganica, Dipartimento Di Chimica, Polo Scientifico, Università degli Studi di Firenze, Sesto Fiorentino, Florence, Italy,
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Polo Scientifico, Sesto Fiorentino, Florence, Italy, and
| | | | | | - Sameh M Osman
- Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Zeid AlOthman
- Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Claudiu T Supuran
- Laboratorio di Chimica Bioinorganica, Dipartimento Di Chimica, Polo Scientifico, Università degli Studi di Firenze, Sesto Fiorentino, Florence, Italy,
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Polo Scientifico, Sesto Fiorentino, Florence, Italy, and
- Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
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Vullo D, De Luca V, Del Prete S, Carginale V, Scozzafava A, Capasso C, Supuran CT. Sulfonamide inhibition studies of the γ-carbonic anhydrase from the Antarctic bacterium Pseudoalteromonas haloplanktis. Bioorg Med Chem Lett 2015; 25:3550-5. [PMID: 26174556 DOI: 10.1016/j.bmcl.2015.06.079] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 06/22/2015] [Accepted: 06/23/2015] [Indexed: 12/18/2022]
Abstract
The Antarctic bacterium Pseudoalteromonas haloplanktis encodes for a γ-class carbonic anhydrase (CA, EC 4.2.1.1), which was cloned, purified and characterized. The enzyme (PhaCAγ) has a good catalytic activity for the physiologic reaction of CO2 hydration to bicarbonate and protons, with a k(cat) of 1.4×10(5) s(-1) and a k(cat)/K(m) of 1.9×10(6) M(-1)×s(-1). A series of sulfonamides and a sulfamate were investigated as inhibitors of the new enzyme. Methazolamide and indisulam showed the best inhibitory properties (K(I)s of 86.7-94.7 nM). This contribution shed new light on γ-CAs inhibition profiles with a relevant class of pharmacologic agents.
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Affiliation(s)
- Daniela Vullo
- Università degli Studi di Firenze, Dipartimento Di Chimica, Laboratorio di Chimica Bioinorganica, Polo Scientifico, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Viviana De Luca
- Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 81, Napoli, Italy
| | - Sonia Del Prete
- Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 81, Napoli, Italy; Università degli Studi di Firenze, Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Polo Scientifico, Via U. Schiff 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Vincenzo Carginale
- Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 81, Napoli, Italy
| | - Andrea Scozzafava
- Università degli Studi di Firenze, Dipartimento Di Chimica, Laboratorio di Chimica Bioinorganica, Polo Scientifico, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Clemente Capasso
- Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 81, Napoli, Italy.
| | - Claudiu T Supuran
- Università degli Studi di Firenze, Dipartimento Di Chimica, Laboratorio di Chimica Bioinorganica, Polo Scientifico, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy; Università degli Studi di Firenze, Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Polo Scientifico, Via U. Schiff 6, 50019 Sesto Fiorentino, Florence, Italy.
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6
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Doering JA, Beitel SC, Eisner BK, Heide T, Hollert H, Giesy JP, Hecker M, Wiseman SB. Identification and response to metals of metallothionein in two ancient fishes: white sturgeon (Acipenser transmontanus) and lake sturgeon (Acipenser fulvescens). Comp Biochem Physiol C Toxicol Pharmacol 2015; 171:41-8. [PMID: 25795035 DOI: 10.1016/j.cbpc.2015.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 03/06/2015] [Accepted: 03/11/2015] [Indexed: 01/31/2023]
Abstract
White sturgeon (Acipenser transmontanus) are among the most sensitive species of fishes to Cu, Cd, and Zn, but there is no information about sensitivity of lake sturgeon (Acipenser fulvescens). To begin to elucidate molecular mechanism(s) of sensitivity of sturgeons to metals a cDNA encoding metallothionein (MT) was amplified from livers of white sturgeon (WS-MT) and lake sturgeon (LS-MT), and expression in response to Cu, Cd, or Zn was characterized in liver explants from each species. The primary structure of WS-MT and LS-MT contained 20 cysteine residues, which is the same as MTs of teleost fishes. However, the primary structure of WS-MT and LS-MT contained 63 amino acids, which is longer than any MT identified in teleost fishes. Abundance of transcripts of WS-MT in explants exposed to 0.3, 3, 30, or 100 μg/L of Cu was 1.7-, 1.7-, 2.1-, and 2.6-fold less than in controls, respectively. In contrast, abundances of transcripts of WS-MT were 3.3- and 2.4-fold greater in explants exposed to 30 μg/L of Cd and 1000 μg/L of Zn, respectively. Abundance of transcripts of LS-MT was not significantly different at any concentration of Cu, Cd, or Zn. MT is hypothesized to represent a critical mechanism for detoxification of metals. Therefore, results of this study suggest that sensitivity of sturgeons to exposure to Cu, Cd, or Zn might be a result of the relatively lesser maximal response of MT to metals. The study also suggestslake sturgeon might be more sensitive than white sturgeon to metals.
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Affiliation(s)
- Jon A Doering
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; Toxicology Graduate Program, University of Saskatchewan, Saskatoon, SK, Canada
| | - Shawn C Beitel
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; Toxicology Graduate Program, University of Saskatchewan, Saskatoon, SK, Canada
| | - Bryanna K Eisner
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Timon Heide
- Institute for Environmental Research, RWTH University, Aachen, Germany
| | - Henner Hollert
- Institute for Environmental Research, RWTH University, Aachen, Germany
| | - John P Giesy
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, Canada; Department of Biology and Chemistry, State Key Laboratory for Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; School of Biological Science, University of Hong Kong, Hong Kong, China
| | - Markus Hecker
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; School of the Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada.
| | - Steve B Wiseman
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada
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Vullo D, De Luca V, Del Prete S, Carginale V, Scozzafava A, Capasso C, Supuran CT. Sulfonamide inhibition studies of the γ-carbonic anhydrase from the Antarctic cyanobacterium Nostoc commune. Bioorg Med Chem 2015; 23:1728-34. [PMID: 25773015 DOI: 10.1016/j.bmc.2015.02.045] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 02/11/2015] [Accepted: 02/24/2015] [Indexed: 02/09/2023]
Abstract
A carbonic anhydrase (CA, EC 4.2.1.1) belonging to the γ-class has been cloned, purified and characterized from the Antarctic cyanobacterium Nostoc commune. The enzyme showed a good catalytic activity for the physiologic reaction (hydration of carbon dioxide to bicarbonate and a proton) with the following kinetic parameters, kcat of 9.5×10(5)s(-1) and kcat/KM of 8.3×10(7)M(-1)s(-1), being the γ-CA with the highest catalytic activity described so far. A range of aromatic/heterocyclic sulfonamides and one sulfamate were investigated as inhibitors of the new enzyme, denominated here NcoCA. The best NcoCA inhibitors were some sulfonylated sulfanilamide derivatives possessing elongated molecules, aminobenzolamide, acetazolamide, benzolamide, dorzolamide, brinzolamide and topiramate, which showed inhibition constants in the range of 40.3-92.3nM. As 1,5-bisphosphate carboxylase/oxygenase (RubisCO) and γ-CAs are closely associated in carboxysomes of cyanobacteria for enhancing the affinity of RubisCO for CO2 and the efficiency of photosynthesis, investigation of this new enzyme and its affinity for modulators of its activity may bring new insights in these crucial processes.
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Affiliation(s)
- Daniela Vullo
- Università degliStudi di Firenze, Dipartimento Di Chimica, Laboratorio di ChimicaBioinorganica, Polo Scientifico, Via della Lastruccia3, 50019 Sesto Fiorentino, Florence, Italy
| | - Viviana De Luca
- Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 81, Napoli, Italy
| | - Sonia Del Prete
- Università degliStudi di Firenze, Dipartimento Di Chimica, Laboratorio di ChimicaBioinorganica, Polo Scientifico, Via della Lastruccia3, 50019 Sesto Fiorentino, Florence, Italy; Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 81, Napoli, Italy
| | - Vincenzo Carginale
- Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 81, Napoli, Italy
| | - Andrea Scozzafava
- Università degliStudi di Firenze, Dipartimento Di Chimica, Laboratorio di ChimicaBioinorganica, Polo Scientifico, Via della Lastruccia3, 50019 Sesto Fiorentino, Florence, Italy
| | - Clemente Capasso
- Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 81, Napoli, Italy.
| | - Claudiu T Supuran
- Università degliStudi di Firenze, Dipartimento Di Chimica, Laboratorio di ChimicaBioinorganica, Polo Scientifico, Via della Lastruccia3, 50019 Sesto Fiorentino, Florence, Italy; Università degliStudi di Firenze, DipartimentoNeurofarba, Sezione di ScienzeFarmaceutiche, Polo Scientifico, Via U. Schiff 6, 50019 Sesto Fiorentino, Florence, Italy.
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8
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Digilio G, Bracco C, Vergani L, Botta M, Osella D, Viarengo A. The cadmium binding domains in the metallothionein isoform Cd7-MT10 from Mytilus galloprovincialis revealed by NMR spectroscopy. J Biol Inorg Chem 2008; 14:167-78. [DOI: 10.1007/s00775-008-0435-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 09/29/2008] [Indexed: 10/21/2022]
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9
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Trinchella F, Riggio M, Filosa S, Parisi E, Scudiero R. Molecular cloning and sequencing of metallothionein in squamates: New insights into the evolution of the metallothionein genes in vertebrates. Gene 2008; 423:48-56. [DOI: 10.1016/j.gene.2008.06.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Revised: 06/18/2008] [Accepted: 06/23/2008] [Indexed: 12/11/2022]
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10
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Nishino Y, Yasunaga T, Miyazawa A. A genetically encoded metallothionein tag enabling efficient protein detection by electron microscopy. JOURNAL OF ELECTRON MICROSCOPY 2007; 56:93-101. [PMID: 17967812 DOI: 10.1093/jmicro/dfm008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The observation of biological materials by transmission electron microscopy (TEM) frequently requires the use of negative staining and/or immuno-gold labeling to visualize or identify the specimen, but these techniques are limited. In contrast, genetic labeling with green fluorescent protein (GFP) and its homologs have led to rapid advances in the observation of proteins of interest in cells by light microscopy (LM). These fluorescent tags allow for the visualization of dynamic processes in live cells without the use of secondary reagents. Here, we report the development of an artificial metalloprotein fusion protein expressed in Escherichia coli grown in Cd(2+)-containing medium that allows for efficient protein detection by TEM without additional staining steps. We linked the subunits of the bacterial 14-mer protein GroEL with three repeats of metallothionein (3MT). The 3MT-fused GroEL (GroEL-14(3MT)) was successfully expressed in E. coli, and the purified protein included 250 cadmium atoms per molecule on average. Cd(2+)-bound GroEL-14(3MT) was detected by TEM in the absence of negative staining on a carbon grid, and the particle densities of GroEL-14(3MT) were much greater than those of untagged GroEL in vitreous ice. Taken together, our data indicate that the 3MT tag provides a promising means of allowing the identification of oligomeric proteins isolated from cells in the absence of other detection techniques.
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Affiliation(s)
- Yuri Nishino
- Bio-multisome Research Team, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
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Capasso C, Carginale V, Crescenzi O, Di Maro D, Spadaccini R, Temussi PA, Parisi E. Structural and functional studies of vertebrate metallothioneins: cross-talk between domains in the absence of physical contact. Biochem J 2006; 391:95-103. [PMID: 15926886 PMCID: PMC1237143 DOI: 10.1042/bj20050335] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In previous studies, we showed that the chemical and dynamic properties of fish and mouse MTs (metallothioneins) present a number of distinctive differences linked to their primary structures, and that phylogenetic relationships of mammal and fish MTs correlate with their three-dimensional structures. The different behaviours of MTs may also be linked to the interaction between their two domains. In the present study, we have compared the physicochemical properties of the isolated recombinant domains constituting Notothenia coriiceps and mouse MTs, and compared them with those of the corresponding whole MTs. NMR spectra of the separated domains of N. coriiceps are almost superimposable on those of the parent MT, suggesting an apparent lack of interaction between the two domains in the protein. However, certain dynamic and physicochemical features of the isolated domains are unlike those of the whole protein. In particular, the temperature-induced changes in the chiroptical properties, thiol reactivity of the Zn-MT domains and the Zn2+/Cd2+ rate of exchange are different for the two domains and with respect to the whole protein. Taken together, these results provide a strong argument in favour of the interaction of the two domains in the MT molecule, in spite of the elusive evidence provided by the structural analyses.
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Affiliation(s)
- Clemente Capasso
- CNR, Institute of Protein Biochemistry, via P. Castellino 111 I 80131 Naples, Italy
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12
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Scudiero R, Temussi PA, Parisi E. Fish and mammalian metallothioneins: a comparative study. Gene 2005; 345:21-6. [PMID: 15716090 DOI: 10.1016/j.gene.2004.11.024] [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] [Received: 09/14/2004] [Accepted: 11/09/2004] [Indexed: 11/21/2022]
Abstract
Structural studies show that fish and mammalian metallothioneins are endowed of distinctive features. In particular, the ninth cysteine residue present in the alpha domain of fish metallothionein is shifted of two positions with respect to the mammalian metallothionein, introducing a conformational modification in the protein structure. In addition, the fish metallothionein is less hydrophobic and more flexible than its mammalian counterpart. Our previous studies showed that the hydropathy of piscine and mammalian metallothioneins is significantly correlated with organismal temperature. In the present paper we have performed phylogenetic comparative analysis on metallothioneins of 24 species of fish and mammals. The results of such analysis failed to indicate that metallothionein hydropathy is an adaptive response to the thermal regime of the species. We concluded that metallothionein hydropathy is a trait that did not evolve in association with environmental changes.
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Affiliation(s)
- Rosaria Scudiero
- Department of Evolutionary and Comparative Biology, University Federico II, via Mezzocannone 8, Napoli, Italy
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Capasso C, Carginale V, Crescenzi O, Di Maro D, Parisi E, Spadaccini R, Temussi PA. Solution structure of MT_nc, a novel metallothionein from the Antarctic fish Notothenia coriiceps. Structure 2003; 11:435-43. [PMID: 12679021 DOI: 10.1016/s0969-2126(03)00044-3] [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: 10/27/2022]
Abstract
The structure of [113Cd(7)]-metallothionein (MT_nc) of the Antarctic fish Notothenia coriiceps, the first three-dimensional structure of a fish metallothionein, was determined by homonuclear 1H NMR experiments and heteronuclear [1H, 113Cd]-correlation spectroscopy. MT_nc is composed of an N-terminal beta domain with 9 cysteines and 3 metal ions and a carboxy-terminal alpha-domain with 11 cysteines and 4 metal ions. The position of the ninth Cys of the alpha domain of MT_nc is different from the corresponding Cys of mammalian MTs. As a result, the last CXCC motif in the mammalian MT sequence becomes CXXXCC in the fish MT. This difference leads to a structural change of the alpha domain and, in turn, to a different charge distribution with respect to that observed in mammalian metallothioneins.
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Affiliation(s)
- Clemente Capasso
- CNR, Institute of Protein Biochemistry, via Marconi 10, I 80125, Naples, Italy
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Vergani L, Grattarola M, Dondero F, Viarengo A. Expression, purification, and characterization of metallothionein-A from rainbow trout. Protein Expr Purif 2003; 27:338-45. [PMID: 12597895 DOI: 10.1016/s1046-5928(02)00631-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Recombinant metallothionein A (MT-A) from rainbow trout has been successfully produced in milligram quantities in Escherichia coli. cDNA has been subcloned into pGEX-6P.1 vector, in-frame with a sequence encoding an N-terminal glutathione-S-transferase (GST) tail. Purification to electrophoretic homogeneity has been obtained by affinity chromatography using GSH-Sepharose. After enzymatic cleavage of GST tail, the MT-A moiety shows a molecular weight, corresponding to the expected one (6630 Da). The final yield of the entire expression and purification process was about 5 mg of pure metallothionein per liter of bacterial culture. The effects of different reducing and alkylating agents have been evaluated at the level of the formation of higher molecular weight aggregates. To investigate the metal-binding ability of the recombinant MT-A, we carried out a spectrophotometrical titration with cadmium ions. Finally, we checked the metal dissociation by recording the UV absorbance of the protein as a function of the environmental pH.
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Affiliation(s)
- Laura Vergani
- Department of Biophysical M & O Sciences and Technologies, Biophysical Division, University of Genova Medical School, Corso Europa 30, Genoa 16132, Italy.
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