1
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Cascarina SM, Ross ED. Identification of Low-Complexity Domains by Compositional Signatures Reveals Class-Specific Frequencies and Functions Across the Domains of Life. PLoS Comput Biol 2024; 20:e1011372. [PMID: 38748749 PMCID: PMC11132505 DOI: 10.1371/journal.pcbi.1011372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 05/28/2024] [Accepted: 05/04/2024] [Indexed: 05/29/2024] Open
Abstract
Low-complexity domains (LCDs) in proteins are typically enriched in one or two predominant amino acids. As a result, LCDs often exhibit unusual structural/biophysical tendencies and can occupy functional niches. However, for each organism, protein sequences must be compatible with intracellular biomolecules and physicochemical environment, both of which vary from organism to organism. This raises the possibility that LCDs may occupy sequence spaces in select organisms that are otherwise prohibited in most organisms. Here, we report a comprehensive survey and functional analysis of LCDs in all known reference proteomes (>21k organisms), with added focus on rare and unusual types of LCDs. LCDs were classified according to both the primary amino acid and secondary amino acid in each LCD sequence, facilitating detailed comparisons of LCD class frequencies across organisms. Examination of LCD classes at different depths (i.e., domain of life, organism, protein, and per-residue levels) reveals unique facets of LCD frequencies and functions. To our surprise, all 400 LCD classes occur in nature, although some are exceptionally rare. A number of rare classes can be defined for each domain of life, with many LCD classes appearing to be eukaryote-specific. Certain LCD classes were consistently associated with identical functions across many organisms, particularly in eukaryotes. Our analysis methods enable simultaneous, direct comparison of all LCD classes between individual organisms, resulting in a proteome-scale view of differences in LCD frequencies and functions. Together, these results highlight the remarkable diversity and functional specificity of LCDs across all known life forms.
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Affiliation(s)
- Sean M. Cascarina
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Eric D. Ross
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States of America
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2
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García-Risco M, Calatayud S, Pedrini-Martha V, Albalat R, Palacios Ò, Capdevila M, Dallinger R. A de novo evolved domain improves the cadmium detoxification capacity of limpet metallothioneins. Sci Rep 2023; 13:8895. [PMID: 37264073 DOI: 10.1038/s41598-023-35786-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/23/2023] [Indexed: 06/03/2023] Open
Abstract
Metallothioneins (MTs) constitute an important family of metal binding proteins. Mollusk MTs, in particular, have been used as model systems to better understand the evolution of their metal binding features and functional adaptation. In the present study two recombinantly produced MTs, LgiMT1 and LgiMT2, and their de novo evolved γ domain, of the marine limpet Lottia gigantea, were analyzed by electronic spectroscopy and mass spectrometry. Both MT proteins, as well as their γ domains, exhibit a strong binding specificity for Cd(II), but not for Zn(II) or Cu(I). The LgiMTs' γ domain renders an MII4(SCys)10 cluster with an increased Cd stoichiometry (binding 4 instead of 3 Cd2+ ions), representing a novel structural element in the world of MTs, probably featuring an adamantane 3D structure. This cluster significantly improves the Cd(II)-binding performance of the full length proteins and thus contributes to the particularly high Cd coping capacity observed in free-living limpets.
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Affiliation(s)
- Mario García-Risco
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Spain
| | - Sara Calatayud
- Departament de Genètica, Facultat de Biologia, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Veronika Pedrini-Martha
- Institute of Zoology, Center of Molecular Biosciences, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - Ricard Albalat
- Departament de Genètica, Facultat de Biologia, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Òscar Palacios
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Spain
| | - Mercè Capdevila
- Departament de Química, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Spain.
| | - Reinhard Dallinger
- Institute of Zoology, Center of Molecular Biosciences, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
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3
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Singh AK, Pomorski A, Wu S, Peris-Díaz MD, Czepczyńska-Krężel H, Krężel A. The connection of α- and β-domains in mammalian metallothionein-2 differentiates Zn(II) binding affinities, affects folding, and determines zinc buffering properties. Metallomics 2023; 15:mfad029. [PMID: 37147085 PMCID: PMC10243857 DOI: 10.1093/mtomcs/mfad029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 05/03/2023] [Indexed: 05/07/2023]
Abstract
Mammalian metallothioneins (MTs) are small Cys-rich proteins involved in Zn(II) and Cu(I) homeostasis. They bind seven Zn(II) ions in two distinct β- and α-domains, forming Zn3Cys9 and Zn4Cys11 clusters, respectively. After six decades of research, their role in cellular buffering of Zn(II) ions has begun to be understood recently. This is because of different affinities of bound ions and the proteins' coexistence in variously Zn(II)-loaded Zn4-7MT species in the cell. To date, it has remained unclear how these mechanisms of action occur and how the affinities are differentiated despite the Zn(S-Cys)4 coordination environment being the same. Here, we dissect the molecular basis of these phenomena by using several MT2 mutants, hybrid protein, and isolated domains. Through a combination of spectroscopic and stability studies, thiol(ate) reactivity, and steered molecular dynamics, we demonstrate that both protein folding and thermodynamics of Zn(II) ion (un)binding significantly differ between isolated domains and the whole protein. Close proximity reduces the degrees of freedom of separated domains, making them less dynamic. It is caused by the formation of intra- and interdomain electrostatic interactions. The energetic consequence of domains connection has a critical impact on the role of MTs in the cellular environment, where they function not only as a zinc sponge but also as a zinc buffering system keeping free Zn(II) in the right concentrations. Any change of that subtle system affects the folding mechanism, zinc site stabilities, and cellular zinc buffer components.
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Affiliation(s)
- Avinash Kumar Singh
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Adam Pomorski
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Sylwia Wu
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Manuel D Peris-Díaz
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Hanna Czepczyńska-Krężel
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Artur Krężel
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
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4
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Medvedeva YV, Yin HZ, Bazrafkan A, Yeromin A, Ji SG, Weiss-Hung EJ, Sharman E, Avilez AP, Maki N, Rafi MA, Tian G, Akbari Y, Weiss JH. Blocking Mitochondrial Zn 2+ Accumulation after Ischemia Reduces Mitochondrial Dysfunction and Neuronal Injury. J Neurosci 2022; 42:5281-5292. [PMID: 35623885 PMCID: PMC9236293 DOI: 10.1523/jneurosci.0874-21.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 04/22/2022] [Accepted: 05/18/2022] [Indexed: 12/31/2022] Open
Abstract
Zn2+ is an important contributor to ischemic brain injury, and recent studies support the hypothesis that mitochondria are key sites of its injurious effects. In murine hippocampal slices (both sexes) subjected to oxygen glucose deprivation (OGD), we found that Zn2+ accumulation and its entry into mitochondria precedes and contributes to the induction of acute neuronal death. In addition, if the ischemic episode is short (and sublethal), there is ongoing Zn2+ accumulation in CA1 mitochondria after OGD that may contribute to their delayed dysfunction. Using this slice model of sublethal OGD, we have examined Zn2+ contributions to the progression of changes evoked by OGD and occurring over 4-5 h. We detected progressive mitochondrial depolarization occurring from ∼2 h after ischemia, a large increase in spontaneous synaptic activity between 2 and 3 h, and mitochondrial swelling and fragmentation at 4 h. Blockade of the primary route for Zn2+ entry, the mitochondrial Ca2+ uniporter (with ruthenium red [RR]) or Zn2+ chelation shortly after OGD withdrawal substantially attenuated the mitochondrial depolarization and the changes in synaptic activity. RR also largely reversed the mitochondrial swelling. Finally, using an in vivo rat (male) asphyxial cardiac arrest model of transient global ischemia, we found that ∼8 min asphyxia induces considerable injury of CA1 neurons 4 h later that is associated with strong Zn2+ accumulation within many damaged mitochondria. These effects were substantially attenuated by infusion of RR on reperfusion. Our findings highlight mitochondrial Zn2+ accumulation after ischemia as a possible target for neuroprotective therapy.SIGNIFICANCE STATEMENT Brain ischemia is a leading cause of mortality and long-term disability that still lacks effective treatment. After transient ischemia, delayed death of neurons occurs in vulnerable brain regions. There is a critical need to understand mechanisms of this delayed neurodegeneration which can be targeted for neuroprotection. We found progressive and long-lasting mitochondrial Zn2+ accumulation to occur in highly vulnerable CA1 neurons after ischemia. Here we demonstrate that this Zn2+ accumulation contributes strongly to deleterious events occurring after ischemia, including mitochondrial dysfunction, swelling, and structural changes. We suggest that this mitochondrial Zn2+ entry may constitute a promising target for development of therapeutic interventions to be delivered after termination of an episode of transient global ischemia.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Yama Akbari
- Departments of Neurology
- Anatomy & Neurobiology
- Neurological surgery
- Beckman Laser Institute & Medical Clinic, University of California Irvine, Irvine, California 92697
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5
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Mehlenbacher MR, Elsiesy R, Lakha R, Villones RLE, Orman M, Vizcarra CL, Meloni G, Wilcox DE, Austin RN. Metal binding and interdomain thermodynamics of mammalian metallothionein-3: enthalpically favoured Cu + supplants entropically favoured Zn 2+ to form Cu 4 + clusters under physiological conditions. Chem Sci 2022; 13:5289-5304. [PMID: 35655557 PMCID: PMC9093145 DOI: 10.1039/d2sc00676f] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 04/01/2022] [Indexed: 01/02/2023] Open
Abstract
Metallothioneins (MTs) are a ubiquitous class of small metal-binding proteins involved in metal homeostasis and detoxification. While known for their high affinity for d10 metal ions, there is a surprising dearth of thermodynamic data on metals binding to MTs. In this study, Zn2+ and Cu+ binding to mammalian metallothionein-3 (MT-3) were quantified at pH 7.4 by isothermal titration calorimetry (ITC). Zn2+ binding was measured by chelation titrations of Zn7MT-3, while Cu+ binding was measured by Zn2+ displacement from Zn7MT-3 with competition from glutathione (GSH). Titrations in multiple buffers enabled a detailed analysis that yielded condition-independent values for the association constant (K) and the change in enthalpy (ΔH) and entropy (ΔS) for these metal ions binding to MT-3. Zn2+ was also chelated from the individual α and β domains of MT-3 to quantify the thermodynamics of inter-domain interactions in metal binding. Comparative titrations of Zn7MT-2 with Cu+ revealed that both MT isoforms have similar Cu+ affinities and binding thermodynamics, indicating that ΔH and ΔS are determined primarily by the conserved Cys residues. Inductively coupled plasma mass spectrometry (ICP-MS) analysis and low temperature luminescence measurements of Cu-replete samples showed that both proteins form two Cu4 +-thiolate clusters when Cu+ displaces Zn2+ under physiological conditions. Comparison of the Zn2+ and Cu+ binding thermodynamics reveal that enthalpically-favoured Cu+, which forms Cu4 +-thiolate clusters, displaces the entropically-favoured Zn2+. These results provide a detailed thermodynamic analysis of d10 metal binding to these thiolate-rich proteins and quantitative support for, as well as molecular insight into, the role that MT-3 plays in the neuronal chemistry of copper.
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Affiliation(s)
| | - Rahma Elsiesy
- Department of Chemistry, Barnard College of Columbia University New York NY 10027 USA
| | - Rabina Lakha
- Department of Chemistry, Barnard College of Columbia University New York NY 10027 USA
| | - Rhiza Lyne E Villones
- Department of Chemistry and Biochemistry, University of Texas at Dallas Richardson TX 75080 USA
| | - Marina Orman
- Department of Chemistry, Barnard College of Columbia University New York NY 10027 USA
| | - Christina L Vizcarra
- Department of Chemistry, Barnard College of Columbia University New York NY 10027 USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, University of Texas at Dallas Richardson TX 75080 USA
| | - Dean E Wilcox
- Department of Chemistry, Dartmouth College Hanover NH 03755 USA
| | - Rachel N Austin
- Department of Chemistry, Barnard College of Columbia University New York NY 10027 USA
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6
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Yuan L, Wang WX. Bioimaging revealed contrasting organelle-specific transport of copper and zinc and implication for toxicity. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 299:118891. [PMID: 35077835 DOI: 10.1016/j.envpol.2022.118891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Zn and Cu are two of the essential trace elements and it is important to understand the regulation of their distribution on cellular functions. Herein, we for the first time investigated the subcellular fate and behavior of Zn and Cu in zebrafish cells through bioimaging, and demonstrated the completely different behaviors of Zn and Cu. The distribution of Zn2+ was concentration-dependent, and Zn2+ at low concentration was predominantly located in the lysosomes (76.5%). A further increase of cellular Zn2+ resulted in a spillover and more diffusive distribution, with partitioning to mitochondria and other regions. In contrast, the subcellular distribution of Cu+ was time-dependent. Upon entering the cells, Cu2+ was reduced to Cu+, which was first concentrated in the mitochondria (71.4%) followed by transportation to lysosomes (58.6%), and finally removal from the cell. With such differential transportation, Cu2+ instead of Zn2+ had a negative effect on the mitochondrial membrane potential and glutathione. Correspondingly, the pH of lysosomes was more sensitive to Zn2+ exposure and decreased with increasing internalized Zn2+, whereas it increased upon Cu2+ exposure. The responses of cellular pH showed an opposite pattern from the lysosomal pH. Lysosome was the most critical organelle in response to incoming Zn2+ by increasing its number and size, whereas Cu2+ reduced the lysosome size. Our study showed that Zn2+ and Cu2+ had completely different cellular handlings and fates with important implications for understanding of their toxicity.
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Affiliation(s)
- Liuliang Yuan
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Wen-Xiong Wang
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China.
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7
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Abstract
The functions, purposes, and roles of metallothioneins have been the subject of speculations since the discovery of the protein over 60 years ago. This article guides through the history of investigations and resolves multiple contentions by providing new interpretations of the structure-stability-function relationship. It challenges the dogma that the biologically relevant structure of the mammalian proteins is only the one determined by X-ray diffraction and NMR spectroscopy. The terms metallothionein and thionein are ambiguous and insufficient to understand biological function. The proteins need to be seen in their biological context, which limits and defines the chemistry possible. They exist in multiple forms with different degrees of metalation and types of metal ions. The homoleptic thiolate coordination of mammalian metallothioneins is important for their molecular mechanism. It endows the proteins with redox activity and a specific pH dependence of their metal affinities. The proteins, therefore, also exist in different redox states of the sulfur donor ligands. Their coordination dynamics allows a vast conformational landscape for interactions with other proteins and ligands. Many fundamental signal transduction pathways regulate the expression of the dozen of human metallothionein genes. Recent advances in understanding the control of cellular zinc and copper homeostasis are the foundation for suggesting that mammalian metallothioneins provide a highly dynamic, regulated, and uniquely biological metal buffer to control the availability, fluctuations, and signaling transients of the most competitive Zn(II) and Cu(I) ions in cellular space and time.
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Affiliation(s)
- Artur Krężel
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Wrocław 50-383, Poland
| | - Wolfgang Maret
- Departments of Biochemistry and Nutritional Sciences, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London SE1 9NH, U.K
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8
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Peris-Díaz M, Guran R, Domene C, de los Rios V, Zitka O, Adam V, Krężel A. An Integrated Mass Spectrometry and Molecular Dynamics Simulations Approach Reveals the Spatial Organization Impact of Metal-Binding Sites on the Stability of Metal-Depleted Metallothionein-2 Species. J Am Chem Soc 2021; 143:16486-16501. [PMID: 34477370 PMCID: PMC8517974 DOI: 10.1021/jacs.1c05495] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 12/16/2022]
Abstract
Mammalian metallothioneins (MTs) are a group of cysteine-rich proteins that bind metal ions in two α- and β-domains and represent a major cellular Zn(II)/Cu(I) buffering system in the cell. At cellular free Zn(II) concentrations (10-11-10-9 M), MTs do not exist in fully loaded forms with seven Zn(II)-bound ions (Zn7MTs). Instead, MTs exist as partially metal-depleted species (Zn4-6MT) because their Zn(II) binding affinities are on the nano- to picomolar range comparable to the concentrations of cellular Zn(II). The mode of action of MTs remains poorly understood, and thus, the aim of this study is to characterize the mechanism of Zn(II) (un)binding to MTs, the thermodynamic properties of the Zn1-6MT2 species, and their mechanostability properties. To this end, native mass spectrometry (MS) and label-free quantitative bottom-up and top-down MS in combination with steered molecular dynamics simulations, well-tempered metadynamics (WT-MetaD), and parallel-bias WT-MetaD (amounting to 3.5 μs) were integrated to unravel the chemical coordination of Zn(II) in all Zn1-6MT2 species and to explain the differences in binding affinities of Zn(II) ions to MTs. Differences are found to be the result of the degree of water participation in MT (un)folding and the hyper-reactive character of Cys21 and Cys29 residues. The thermodynamics properties of Zn(II) (un)binding to MT2 are found to differ from those of Cd(II), justifying their distinctive roles. The potential of this integrated strategy in the investigation of numerous unexplored metalloproteins is attested by the results highlighted in the present study.
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Affiliation(s)
- Manuel
David Peris-Díaz
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Roman Guran
- Department
of Chemistry and Biochemistry, Mendel University
in Brno, Zemedelska 1, 613 00 Brno, Czech Republic
- Central
European Institute of Technology, Brno University
of Technology, Purkynova
123, 612 00 Brno, Czech Republic
| | - Carmen Domene
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
- Department
of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Vivian de los Rios
- Functional
Proteomics, Department of Cellular and Molecular Medicine and Proteomic
Facility, Centro de Investigaciones Biológicas
(CIB-CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Ondrej Zitka
- Department
of Chemistry and Biochemistry, Mendel University
in Brno, Zemedelska 1, 613 00 Brno, Czech Republic
- Central
European Institute of Technology, Brno University
of Technology, Purkynova
123, 612 00 Brno, Czech Republic
| | - Vojtech Adam
- Department
of Chemistry and Biochemistry, Mendel University
in Brno, Zemedelska 1, 613 00 Brno, Czech Republic
- Central
European Institute of Technology, Brno University
of Technology, Purkynova
123, 612 00 Brno, Czech Republic
| | - Artur Krężel
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, 50-383 Wrocław, Poland
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9
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Sakatoku A, Ishikawa M, Yamazaki K, Nakamachi T, Kamachi H, Tanaka D, Nakamura S. Molecular Identification, Characterization, and Expression Analysis of a Metallothionein Gene from Septifer virgatus. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2020; 22:488-497. [PMID: 32435938 DOI: 10.1007/s10126-020-09970-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
This study provides a preliminary characterization of a metallothionein (MT) gene in Septifer virgatus and highlights its potential use in biomonitoring. The full-length SvMT cDNA and the complete sequence of the SvMT gene were identified using reverse transcriptase PCR coupled with the rapid amplification of cDNA ends and the primer walking method. The SvMT cDNA encodes a protein of 72 amino acids having nine classical Cys-X-Cys motifs. Moreover, the deduced amino acids contained the conserved motif (Cys-x-Cys-x(3)-Cys-Thr-Gly-x(3)-Cys-x-Cys-x(3)-Cys-x-Cys-Lys) of MT family 2. Its molecular mass and isoelectric point were estimated to be 7.01 kDa and 7.00, respectively. BLAST-based searching indicated that SvMT shared 81.0% amino acid sequence identity with Mytilus edulis MT-20-II. The SvMT gene has three coding exons and two introns. After exposure to 1 mg/L cadmium chloride, the expression of SvMT increased 15-fold by 3 days (d), with a maximum expression of 27-fold by 5 d compared with the pre-exposure level. After exposure to 2 mg/L zinc chloride, the expression of SvMT increased 2.5-fold by 3 d and 4.7-fold by 5 d compared with the pre-exposure level. A significant increase in the expression level of SvMT mRNA was observed after the exposure of S. virgatus to the combination of 0.003 mg/L cadmium chloride and 0.2 mg/L zinc chloride compared with the pre-exposure level. Our work indicates that the SvMT gene is associated with stress responses and could be a potential biomarker for marine pollution.
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Affiliation(s)
- Akihiro Sakatoku
- Graduate School of Science and Engineering, Department of Environmental and Energy Science Faculty of Earth and Environmental Systems, University of Toyama, Toyama, 930-8555, Japan.
| | - Masahito Ishikawa
- Graduate School of Science and Engineering, Department of Environmental and Energy Science Faculty of Earth and Environmental Systems, University of Toyama, Toyama, 930-8555, Japan
| | - Kanna Yamazaki
- Graduate School of Science and Engineering, Department of Environmental and Energy Science Faculty of Earth and Environmental Systems, University of Toyama, Toyama, 930-8555, Japan
| | - Tomoya Nakamachi
- Graduate School of Science and Engineering, Department of Environmental and Energy Science Faculty of Earth and Environmental Systems, University of Toyama, Toyama, 930-8555, Japan
| | - Hiroyuki Kamachi
- Graduate School of Science and Engineering, Department of Environmental and Energy Science Faculty of Earth and Environmental Systems, University of Toyama, Toyama, 930-8555, Japan
| | - Daisuke Tanaka
- Graduate School of Science and Engineering, Department of Environmental and Energy Science Faculty of Earth and Environmental Systems, University of Toyama, Toyama, 930-8555, Japan
| | - Shogo Nakamura
- Graduate School of Science and Engineering, Department of Environmental and Energy Science Faculty of Earth and Environmental Systems, University of Toyama, Toyama, 930-8555, Japan
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10
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Malekzadeh R, Shahpiri A, Siapoush S. Metalation of a rice type 1 metallothionein isoform (OsMTI-1b). Protein Expr Purif 2020; 175:105719. [PMID: 32750405 DOI: 10.1016/j.pep.2020.105719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 06/11/2020] [Accepted: 07/25/2020] [Indexed: 11/15/2022]
Abstract
The simultaneously functions of Metallothioneins (MTs) are relied on their metalation mechanisms that can be divided into non-cooperative, weakly cooperative and strongly cooperative mechanisms. In this study, we recombinantly synthesized OsMTI-1b, N- and C-terminal Cys-rich regions as glutathione-S-transferase (GST)-fusion proteins in E. coli. In comparison with control strains (The E. coli cells containing pET41a without gene), transgenic E. coli cells showed more tolerance against Cd2+ and Zn2+. The recombinant GST-proteins were purified using affinity chromatography. According to in vitro assays, the recombinant proteins showed a higher binding ability to Cd2+ and Zn2+. However, the affinity of apo-proteins to Cu2+ ions were very low. The coordination of Cd2+ ions in OsMTI-1b demonstrates a strongly cooperative mechanism with a priority for the C-terminal Cys-rich region that indicates the detoxifying of heavy metals as main role of P1 subfamily of MTs. While the metalation with Zn2+ conformed to a weakly cooperative mechanism with a specificity to N-terminal Cys-rich region. It implies the specific function of OsMTI-1b is involved in zinc homeostasis. Nevertheless, a non-cooperative metalation mechanism was perceived for Cu2+ that suggests the fully metalation does not occur and OsMTI-1b cannot play a significant role in dealing with Cu2+ ions.
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Affiliation(s)
- Rahim Malekzadeh
- Department of Medical Biotechnology, School of Advanced Technologies, Shahrekord University of Medical Sciences, Shahrekord, 88157-13471, Iran; Student Research Committee, Shahrekord University of Medical Sciences, Shahrekord, Iran.
| | - Azar Shahpiri
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Samaneh Siapoush
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Science, Tabriz, 51664-15731, Iran
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11
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Mazmanian K, Sargsyan K, Lim C. How the Local Environment of Functional Sites Regulates Protein Function. J Am Chem Soc 2020; 142:9861-9871. [PMID: 32407086 DOI: 10.1021/jacs.0c02430] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Proteins form complex biological machineries whose functions in the cell are highly regulated at both the cellular and molecular levels. Cellular regulation of protein functions involves differential gene expressions, post-translation modifications, and signaling cascades. Molecular regulation, on the other hand, involves tuning an optimal local protein environment for the functional site. Precisely how a protein achieves such an optimal environment around a given functional site is not well understood. Herein, by surveying the literature, we first summarize the various reported strategies used by certain proteins to ensure their correct functioning. We then formulate three key physicochemical factors for regulating a protein's functional site, namely, (i) its immediate interactions, (ii) its solvent accessibility, and (iii) its conformational flexibility. We illustrate how these factors are applied to regulate the functions of free/metal-bound Cys and Zn sites in proteins.
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Affiliation(s)
- Karine Mazmanian
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Karen Sargsyan
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Carmay Lim
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.,Department of Chemistry, National Tsing Hua University, Hsinchu 300, Taiwan
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12
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Ji SG, Medvedeva YV, Weiss JH. Zn 2+ entry through the mitochondrial calcium uniporter is a critical contributor to mitochondrial dysfunction and neurodegeneration. Exp Neurol 2019; 325:113161. [PMID: 31881218 DOI: 10.1016/j.expneurol.2019.113161] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/19/2019] [Accepted: 12/21/2019] [Indexed: 12/19/2022]
Abstract
Excitotoxic Ca2+ accumulation contributes to ischemic neurodegeneration, and Ca2+ can enter the mitochondria through the mitochondrial calcium uniporter (MCU) to promote mitochondrial dysfunction. Yet, Ca2+-targeted therapies have met limited success. A growing body of evidence has highlighted the underappreciated importance of Zn2+, which also accumulates in neurons after ischemia and can induce mitochondrial dysfunction and cell death. While studies have indicated that Zn2+ can also enter the mitochondria through the MCU, the specificity of the pore's role in Zn2+-triggered injury is still debated. Present studies use recently available MCU knockout mice to examine how the deletion of this channel impacts deleterious effects of cytosolic Zn2+ loading. In cultured cortical neurons from MCU knockout mice, we find significantly reduced mitochondrial Zn2+ accumulation. Correspondingly, these neurons were protected from both acute and delayed Zn2+-triggered mitochondrial dysfunction, including mitochondrial reactive oxygen species generation, depolarization, swelling and inhibition of respiration. Furthermore, when toxic extramitochondrial effects of Ca2+ entry were moderated, both cultured neurons (exposed to Zn2+) and CA1 neurons of hippocampal slices (subjected to prolonged oxygen glucose deprivation to model ischemia) from MCU knockout mice displayed decreased neurodegeneration. Finally, to examine the therapeutic applicability of these findings, we added an MCU blocker after toxic Zn2+ exposure in wildtype neurons (to induce post-insult MCU blockade). This significantly attenuated the delayed evolution of both mitochondrial dysfunction and neurotoxicity. These data-combining both genetic and pharmacologic tools-support the hypothesis that Zn2+ entry through the MCU is a critical contributor to ischemic neurodegeneration that could be targeted for neuroprotection.
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Affiliation(s)
- Sung G Ji
- Department of Anatomy & Neurobiology, University of California, Irvine, United States of America
| | - Yuliya V Medvedeva
- Department of Neurology, University of California, Irvine, United States of America
| | - John H Weiss
- Department of Anatomy & Neurobiology, University of California, Irvine, United States of America; Department of Neurology, University of California, Irvine, United States of America.
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13
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Manceau A, Bustamante P, Haouz A, Bourdineaud JP, Gonzalez‐Rey M, Lemouchi C, Gautier‐Luneau I, Geertsen V, Barruet E, Rovezzi M, Glatzel P, Pin S. Mercury(II) Binding to Metallothionein in Mytilus edulis revealed by High Energy-Resolution XANES Spectroscopy. Chemistry 2019; 25:997-1009. [PMID: 30426580 PMCID: PMC6582439 DOI: 10.1002/chem.201804209] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Indexed: 11/26/2022]
Abstract
Of all divalent metals, mercury (HgII ) has the highest affinity for metallothioneins. HgII is considered to be enclosed in the α and β domains as tetrahedral α-type Hg4 Cys11-12 and β-type Hg3 Cys9 clusters similar to CdII and ZnII . However, neither the four-fold coordination of Hg nor the existence of Hg-Hg atomic pairs have ever been demonstrated, and the HgII partitioning among the two protein domains is unknown. Using high energy-resolution XANES spectroscopy, MP2 geometry optimization, and biochemical analysis, evidence for the coexistence of two-coordinate Hg-thiolate complex and four-coordinate Hg-thiolate cluster with a metacinnabar-type (β-HgS) structure in the α domain of separate metallothionein molecules from blue mussel under in vivo exposure is provided. The findings suggest that the CXXC claw setting of thiolate donors, which only exists in the α domain, acts as a nucleation center for the polynuclear complex and that the five CXC motifs from this domain serve as the cluster-forming motifs. Oligomerization is driven by metallophilic Hg⋅⋅⋅Hg interactions. Our results provide clues as to why Hg has higher affinity for the α than the β domain. More generally, this work provides a foundation for understanding how metallothioneins mediate mercury detoxification in the cell under in vivo conditions.
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Affiliation(s)
- Alain Manceau
- ISTerreUniv. Grenoble Alpes, CNRS38000GrenobleFrance
| | - Paco Bustamante
- Littoral Environnement et Sociétés, LIENSs, Univ. La RochelleCNRS17000La RochelleFrance
| | - Ahmed Haouz
- Institut Pasteur, Plate-forme de CristallographieCNRS,375724ParisFrance
| | | | | | | | | | - Valérie Geertsen
- NIMBE, Univ. Paris-SaclayCNRS, CEA Saclay91191Gif-sur-YvetteFrance
| | - Elodie Barruet
- NIMBE, Univ. Paris-SaclayCNRS, CEA Saclay91191Gif-sur-YvetteFrance
| | - Mauro Rovezzi
- European Synchrotron Radiation FacilityESRF38000GrenobleFrance
| | - Pieter Glatzel
- European Synchrotron Radiation FacilityESRF38000GrenobleFrance
| | - Serge Pin
- NIMBE, Univ. Paris-SaclayCNRS, CEA Saclay91191Gif-sur-YvetteFrance
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14
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Duan L, Kong JJ, Wang TQ, Sun Y. Binding of Cd(II), Pb(II), and Zn(II) to a type 1 metallothionein from maize (Zea mays). Biometals 2018; 31:539-550. [PMID: 29766364 DOI: 10.1007/s10534-018-0100-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 04/03/2018] [Indexed: 10/16/2022]
Affiliation(s)
- Lian Duan
- School of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Jing-Jing Kong
- School of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Tong-Qing Wang
- School of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Yue Sun
- School of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.
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15
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Ji SG, Medvedeva YV, Wang HL, Yin HZ, Weiss JH. Mitochondrial Zn 2+ Accumulation: A Potential Trigger of Hippocampal Ischemic Injury. Neuroscientist 2018; 25:126-138. [PMID: 29742958 DOI: 10.1177/1073858418772548] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Ischemic stroke is a major cause of death and disabilities worldwide, and it has been long hoped that improved understanding of relevant injury mechanisms would yield targeted neuroprotective therapies. While Ca2+ overload during ischemia-induced glutamate excitotoxicity has been identified as a major contributor, failures of glutamate targeted therapies to achieve desired clinical efficacy have dampened early hopes for the development of new treatments. However, additional studies examining possible contributions of Zn2+, a highly prevalent cation in the brain, have provided new insights that may help to rekindle the enthusiasm. In this review, we discuss both old and new findings yielding clues as to sources of the Zn2+ that accumulates in many forebrain neurons after ischemia, and mechanisms through which it mediates injury. Specifically, we highlight the growing evidence of important Zn2+ effects on mitochondria in promoting neuronal injury. A key focus has been to examine Zn2+ contributions to the degeneration of highly susceptible hippocampal pyramidal neurons. Recent studies provide evidence of differences in sources of Zn2+ and its interactions with mitochondria in CA1 versus CA3 neurons that may pertain to their differential vulnerabilities in disease. We propose that Zn2+-induced mitochondrial dysfunction is a critical and potentially targetable early event in the ischemic neuronal injury cascade, providing opportunities for the development of novel neuroprotective strategies to be delivered after transient ischemia.
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Affiliation(s)
- Sung G Ji
- 1 Department of Anatomy & Neurobiology, University of California, Irvine, CA, USA
| | | | - Hwai-Lee Wang
- 2 Department of Neurology, University of California, Irvine, CA, USA.,3 Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
| | - Hong Z Yin
- 2 Department of Neurology, University of California, Irvine, CA, USA
| | - John H Weiss
- 1 Department of Anatomy & Neurobiology, University of California, Irvine, CA, USA.,2 Department of Neurology, University of California, Irvine, CA, USA
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16
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Zhou H, Xu J, Wang W. Functional comparision between truncated MTT1 and truncated MTT2 from Tetrahyemna thermophila. Biosci Biotechnol Biochem 2018; 82:449-455. [DOI: 10.1080/09168451.2018.1431517] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Abstract
Metallothioneins (MTs) are low-molecular-weight proteins with high Cys content and high metal-chelating ability. CdMT and CuMT subfamilies present different characteristics in Tetrahymena. To explore the effect of the cysteine arrangement and sequence length of MTs for binding different metal ions, MTT1, truncated MTT1 (TM1), MTT2, and truncated MTT2 (TM2) were expressed in E. coli. The half-maximal inhibiting concentrations (IC50) of Cd2+ and Cu+ for the recombinant strains were different. Furthermore, E. coli cells expressing MTT1 and TM1 exhibited higher accumulating ability for Cd2+ than cells expressing MTT2 and TM2. However, the opposite is true for Cu+. The binding ability of the different recombinant proteins to Cd2+ and Cu+ were also different. MTT1 and truncated mutant TM1 were the preference for Cd2+, whereas MTT2 and truncated mutant TM2 were the preference for Cu+ coordination. These results showed that metal ion tolerance and accumulation ability not only depended on cysteine arrangement pattern but also on sequence length of MT in Tetrahymena.
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Affiliation(s)
- Huanxin Zhou
- College of Life Science, Shanxi University, Taiyuan, China
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
- School of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan, China
| | - Jing Xu
- College of Life Science, Shanxi University, Taiyuan, China
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
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17
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Zhou H, Xu J, Wang W. Functional analysis of metallothionein MTT5 from
Tetrahymena thermophila. J Cell Biochem 2018; 119:3257-3266. [DOI: 10.1002/jcb.26482] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 10/31/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Huanxin Zhou
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of EducationInstitute of BiotechnologyShanxi UniversityTaiyuanChina
- School of Environment and SafetyTaiyuan University of Science and TechnologyTaiyuanChina
| | - Jing Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of EducationInstitute of BiotechnologyShanxi UniversityTaiyuanChina
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of EducationInstitute of BiotechnologyShanxi UniversityTaiyuanChina
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18
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Drozd A, Wojewska D, Peris-Díaz MD, Jakimowicz P, Krężel A. Crosstalk of the structural and zinc buffering properties of mammalian metallothionein-2. Metallomics 2018; 10:595-613. [DOI: 10.1039/c7mt00332c] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structural insights into partially Zn(ii)-depleted MT2 species and their zinc buffering properties are presented and discussed.
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Affiliation(s)
- Agnieszka Drozd
- Department of Chemical Biology
- Faculty of Biotechnology
- University of Wrocław
- 50-383 Wrocław
- Poland
| | - Dominika Wojewska
- Department of Chemical Biology
- Faculty of Biotechnology
- University of Wrocław
- 50-383 Wrocław
- Poland
| | - Manuel David Peris-Díaz
- Department of Chemical Biology
- Faculty of Biotechnology
- University of Wrocław
- 50-383 Wrocław
- Poland
| | - Piotr Jakimowicz
- Department of Protein Biotechnology
- Faculty of Biotechnology
- University of Wrocław
- 50-383 Wrocław
- Poland
| | - Artur Krężel
- Department of Chemical Biology
- Faculty of Biotechnology
- University of Wrocław
- 50-383 Wrocław
- Poland
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19
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Slepchenko KG, Lu Q, Li YV. Cross talk between increased intracellular zinc (Zn 2+) and accumulation of reactive oxygen species in chemical ischemia. Am J Physiol Cell Physiol 2017; 313:C448-C459. [PMID: 28747335 DOI: 10.1152/ajpcell.00048.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/21/2017] [Accepted: 07/21/2017] [Indexed: 12/16/2022]
Abstract
Both zinc (Zn2+) and reactive oxygen species (ROS) have been shown to accumulate during hypoxic-ischemic stress and play important roles in pathological processes. To understand the cross talk between the two of them, here we studied Zn2+ and ROS accumulation by employing fluorescent probes in HeLa cells to further the understanding of the cause and effect relationship of these two important cellular signaling systems during chemical-ischemia, stimulated by oxygen and glucose deprivation (OGD). We observed two Zn2+ rises that were divided into four phases in the course of 30 min of OGD. The first Zn2+ rise was a transient, which was followed by a latent phase during which Zn2+ levels recovered; however, levels remained above a basal level in most cells. The final phase was the second Zn2+ rise, which reached a sustained plateau called Zn2+ overload. Zn2+ rises were not observed when Zn2+ was removed by TPEN (a Zn2+ chelator) or thapsigargin (depleting Zn2+ from intracellular stores) treatment, indicating that Zn2+ was from intracellular storage. Damaging mitochondria with FCCP significantly reduced the second Zn2+ rise, indicating that the mitochondrial Zn2+ accumulation contributes to Zn2+ overload. We also detected two OGD-induced ROS rises. Two Zn2+ rises preceded two ROS rises. Removal of Zn2+ reduced or delayed OGD- and FCCP-induced ROS generation, indicating that Zn2+ contributes to mitochondrial ROS generation. There was a Zn2+-induced increase in the functional component of NADPH oxidase, p47phox, thus suggesting that NADPH oxidase may mediate Zn2+-induced ROS accumulation. We suggest a new mechanism of cross talk between Zn2+ and mitochondrial ROS through positive feedback processes that eventually causes excessive free Zn2+ and ROS accumulations during the course of ischemic stress.
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Affiliation(s)
- Kira G Slepchenko
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio; and
| | - Qiping Lu
- Department of Biological Sciences, College of Arts and Sciences, Ohio University, Athens, Ohio
| | - Yang V Li
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio; and
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20
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Liu W, Worms IAM, Herlin-Boime N, Truffier-Boutry D, Michaud-Soret I, Mintz E, Vidaud C, Rollin-Genetet F. Interaction of silver nanoparticles with metallothionein and ceruloplasmin: impact on metal substitution by Ag(i), corona formation and enzymatic activity. NANOSCALE 2017; 9:6581-6594. [PMID: 28474724 DOI: 10.1039/c7nr01075c] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The release of Ag(i) from silver nanoparticles (AgNPs) unintentionally spread in the environment is suspected to impair some key biological functions. In comparison with AgNO3, in-depth investigations were carried out into the interactions between citrate-coated AgNPs (20 nm) and two metalloproteins, intracellular metallothionein 1 (MT1) and plasmatic ceruloplasmin (Cp), both involved in metal homeostasis. These were chosen for their physiological relevance and the diversity of their various native metals bound because of thiol groups and/or their structural differences. Transmission electron microscopy (TEM), and dynamic light scattering (DLS), UV-vis and circular dichroism (CD) spectroscopies were used to study the effects of such intricate interactions on AgNP dissolution and proteins in terms of metal exchanges and structural modifications. The isolation of the different populations formed together with on-line quantifications of their metal content were performed by asymmetrical flow field-flow fractionation (AF4) linked to inductively coupled plasma mass spectrometry (ICP-MS). For the 2 proteins, Ag(i) dissolved from the AgNPs, substituted for the native metal, to different extents and with different types of dynamics for the corona formed: the MT1 rapidly surrounded the AgNPs with the transient reticulate corona thus promoting their dissolution associated with the metal substitution, whereas the Cp established a more stable layer around the AgNPs, with a limited substitution of Cu and a decrease in its ferroxidase activity. The accessibility and lability of the metal binding sites inside these proteins and their relative affinities for Ag(i) are discussed, taking into account the structural characteristics of the proteins.
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Affiliation(s)
- Wei Liu
- CEA, DRF-BIAM, Site de Marcoule, F-30207 Bagnols-sur-Cèze, France.
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21
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Wong WP, Allen NB, Meyers MS, Link EO, Zhang X, MacRenaris KW, El Muayed M. Exploring the Association Between Demographics, SLC30A8 Genotype, and Human Islet Content of Zinc, Cadmium, Copper, Iron, Manganese and Nickel. Sci Rep 2017; 7:473. [PMID: 28352089 PMCID: PMC5428289 DOI: 10.1038/s41598-017-00394-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 02/23/2017] [Indexed: 12/30/2022] Open
Abstract
A widely prevalent single nucleotide polymorphism, rs13266634 in the SLC30A8 gene encoding the zinc transporter ZnT8, is associated with an increased risk for T2DM. ZnT8 is mostly expressed in pancreatic insulin-producing islets of Langerhans. The effect of this variant on the divalent metal profile in human islets is unknown. Additionally, essential and non-essential divalent metal content of human islets under normal environmental exposure conditions has not been described. We therefore examined the correlation of zinc and other divalent metals in human islets with rs13266634 genotype and demographic characteristics. We found that the diabetes risk genotype C/C at rs13266634 is associated with higher islet Zn concentration (C/C genotype: 16792 ± 1607, n = 22, C/T genotype: 11221 ± 1245, n = 18 T/T genotype: 11543 ± 6054, n = 3, all values expressed as mean nmol/g protein ± standard error of the mean, p = 0.040 by ANOVA). A positive correlation between islet cadmium content and both age (p = 0.048, R2 = 0.09) and female gender (women: 36.88 ± 4.11 vs men: 21.22 ± 3.65 nmol/g protein, p = 0.007) was observed. Our results suggest that the T2DM risk allele C is associated with higher islet zinc levels and support prior evidence of cadmium's higher bioavailability in women and its long tissue half-life.
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Affiliation(s)
- Winifred P Wong
- Division of Endocrinology, Metabolism and Molecular Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Norrina B Allen
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Matthew S Meyers
- Division of Endocrinology, Metabolism and Molecular Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Emma O Link
- Division of Endocrinology, Metabolism and Molecular Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Xiaomin Zhang
- Division of Transplant Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Keith W MacRenaris
- The Chemistry of Life Processes Institute and Department of Chemistry, Northwestern University, Evanston, IL, 60208, USA
| | - Malek El Muayed
- Division of Endocrinology, Metabolism and Molecular Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
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22
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Jenny MJ, Payton SL, Baltzegar DA, Lozier JD. Phylogenetic Analysis of Molluscan Metallothioneins: Evolutionary Insight from Crassostrea virginica. J Mol Evol 2016; 83:110-125. [DOI: 10.1007/s00239-016-9758-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 09/21/2016] [Indexed: 11/29/2022]
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23
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Irvine GW, Stillman MJ. Cadmium binding mechanisms of isolated domains of human MT isoform 1a: Non-cooperative terminal sites and cooperative cluster sites. J Inorg Biochem 2016; 158:115-121. [DOI: 10.1016/j.jinorgbio.2016.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 03/05/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
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24
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Imaging trace element distributions in single organelles and subcellular features. Sci Rep 2016; 6:21437. [PMID: 26911251 PMCID: PMC4766485 DOI: 10.1038/srep21437] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 01/15/2016] [Indexed: 12/30/2022] Open
Abstract
The distributions of chemical elements within cells are of prime importance in a wide range of basic and applied biochemical research. An example is the role of the subcellular Zn distribution in Zn homeostasis in insulin producing pancreatic beta cells and the development of type 2 diabetes mellitus. We combined transmission electron microscopy with micro- and nano-synchrotron X-ray fluorescence to image unequivocally for the first time, to the best of our knowledge, the natural elemental distributions, including those of trace elements, in single organelles and other subcellular features. Detected elements include Cl, K, Ca, Co, Ni, Cu, Zn and Cd (which some cells were supplemented with). Cell samples were prepared by a technique that minimally affects the natural elemental concentrations and distributions, and without using fluorescent indicators. It could likely be applied to all cell types and provide new biochemical insights at the single organelle level not available from organelle population level studies.
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25
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Chen SH, Russell DH. Reaction of Human Cd7metallothionein and N-Ethylmaleimide: Kinetic and Structural Insights from Electrospray Ionization Mass Spectrometry. Biochemistry 2016; 54:6021-8. [PMID: 26375382 DOI: 10.1021/acs.biochem.5b00545] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction of cadmium-binding human metallothionein-2A (Cd₇MT) and N-ethylmaleimide (NEM) is investigated by electrospray ionization-ion mobility-mass spectrometry (ESI IM-MS). MS provides a direct measure of the distribution of the kinetic intermediates as the reaction proceeds and provides new insights into the relative kinetic stability of the individual metal-thiolate bonds in Cd₇MT. The rate constants for the various metal-retaining intermediates (Cd(i), intermediate with i Cd²⁺ ions attached) differ by >3 orders of magnitude: Cd₄< Cd₃< Cd₂< Cd₁∼ Cd₆ < Cd₇ < Cd5. The reaction is viewed as a two-component cooperative process, rapid loss of three Cd²⁺ ions followed by slow loss of the remaining four Cd²⁺ ions, and Cd₄NEM₁₀MT was observed as the least reactive intermediate during the entire displacement process. "MS-CID-IM-MS", a top-down approach that provides two-dimensional dispersion (size to charge by IM; mass to charge by MS) of the CID fragment ions, was used for direct analysis of the kinetic intermediate [Cd₄NEM₁₀MT]⁵⁺ ion. The results provide direct evidence that the four Cd²⁺ ions located in the α-domain are retained, indicative of the greater kinetic stability for the α-domain. Further, the mapping of the alkylation sites in the [Cd₄NEM₁₀MT]⁵⁺ ion reveals that not only the nine cysteines in the β-domain but Cys33 in the α-domain is selectively labeled. The kinetic lability of the Cd-Cys33 bond is unexpected. The structural and functional implications of these findings are discussed.
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Affiliation(s)
- Shu-Hua Chen
- 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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26
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Rollin-Genetet F, Seidel C, Artells E, Auffan M, Thiéry A, Vidaud C. Redox Reactivity of Cerium Oxide Nanoparticles Induces the Formation of Disulfide Bridges in Thiol-Containing Biomolecules. Chem Res Toxicol 2015; 28:2304-12. [PMID: 26566067 DOI: 10.1021/acs.chemrestox.5b00319] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The redox state of disulfide bonds is implicated in many redox control systems, such as the cysteine-cystine couple. Among proteins, ubiquitous cysteine-rich metallothioneins possess thiolate metal binding groups susceptible to metal exchange in detoxification processes. CeO2 NPs are commonly used in various industrial applications due to their redox properties. These redox properties that enable dual oxidation states (Ce(IV)/Ce(III)) to exist at their surface may act as oxidants for biomolecules. The interaction among metallothioneins, cysteine, and CeO2 NPs was investigated through various biophysical approaches to shed light on the potential effects of the Ce(4+)/Ce(3+) redox system on the thiol groups of these biomolecules. The possible reaction mechanisms include the formation of a disulfide bridge/Ce(III) complex resulting from the interaction between Ce(IV) and the thiol groups, leading to metal unloading from the MTs, depending on their metal content and cluster type. The formation of stable Ce(3+) disulfide complexes has been demonstrated via their fluorescence properties. This work provides the first evidence of thiol concentration-dependent catalytic oxidation mechanisms between pristine CeO2 NPs and thiol-containing biomolecules.
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Affiliation(s)
- Françoise Rollin-Genetet
- CEA/DSV/iBEB/SBTN, Laboratoire d'Etude des Protéines Cibles, BP17171, F-30207 Bagnols sur Cèze Cedex, France.,Labex Serenade Safe(r) Ecodesign Research and Education applied to NAnomaterial DEvelopment
| | - Caroline Seidel
- CEA/DSV/iBEB/SBTN, Laboratoire d'Etude des Protéines Cibles, BP17171, F-30207 Bagnols sur Cèze Cedex, France
| | - Ester Artells
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Technopôle Arbois-Méditerranée, Bât. Villemin - BP 80, F-13545 Aix-en-Provence cedex 04, France.,Labex Serenade Safe(r) Ecodesign Research and Education applied to NAnomaterial DEvelopment
| | - Mélanie Auffan
- Aix-Marseille Université, CNRS, IRD, CEREGE UM34, UMR 7330, F-13545 Aix en Provence, France.,iCEINT International Consortium for the Environmental Implications of Nanotechnology , F-13545 Aix en Provence, France.,Labex Serenade Safe(r) Ecodesign Research and Education applied to NAnomaterial DEvelopment
| | - Alain Thiéry
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Technopôle Arbois-Méditerranée, Bât. Villemin - BP 80, F-13545 Aix-en-Provence cedex 04, France.,iCEINT International Consortium for the Environmental Implications of Nanotechnology , F-13545 Aix en Provence, France.,Labex Serenade Safe(r) Ecodesign Research and Education applied to NAnomaterial DEvelopment
| | - Claude Vidaud
- CEA/DSV/iBEB/SBTN, Laboratoire d'Etude des Protéines Cibles, BP17171, F-30207 Bagnols sur Cèze Cedex, France.,iCEINT International Consortium for the Environmental Implications of Nanotechnology , F-13545 Aix en Provence, France.,Labex Serenade Safe(r) Ecodesign Research and Education applied to NAnomaterial DEvelopment
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27
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Putting the pieces into place: Properties of intact zinc metallothionein 1A determined from interaction of its isolated domains with carbonic anhydrase. Biochem J 2015; 471:347-56. [DOI: 10.1042/bj20150676] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 08/20/2015] [Indexed: 12/25/2022]
Abstract
Competitive metallation reactions between the isolated domain fragments and apo-carbonic anhydrase [CA; metal-free CA (apo-CA)] provided the binding affinities for each of the eight sites and showed that CA competed more efficiently for added zinc with the β-domain fragment. The combined effects of the number of sites, chain length and cysteine accessibility modulate the zinc-binding properties of mammalian metallothionein (MT).
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28
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Kiedrowski L. Neuronal acid-induced [Zn²⁺]i elevations calibrated using the low-affinity ratiometric probe FuraZin-1. J Neurochem 2015; 135:777-86. [PMID: 26263185 DOI: 10.1111/jnc.13282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 08/03/2015] [Accepted: 08/07/2015] [Indexed: 11/30/2022]
Abstract
The experiments were carried out on primary cultures of murine cortical neurons from cryopreserved preparations obtained from embryonic-day-16 fetuses. To calibrate acid-induced intracelluar [Zn(2+) ] ([Zn(2+) ]i ) elevations, a low affinity (Kd = 39 μM at pH 6.1) ratiometric Zn(2+) probe, FuraZin-1, was used. A pHi drop from 7.2 to 6.1 caused [Zn(2+) ]i elevations reaching 2 μM; when the thiol-reactive agent N-ethylmaleimide (NEM) was subsequently applied, [Zn(2+) ]i increased further to 5.6 μM; analogous acid- and NEM-induced [Zn(2+) ]i elevations could also be detected but not calibrated, using the high affinity Zn(2+) probe FluoZin-3. The data indicate that NEM causes Zn(2+) release from ligands that chelate Zn(2+) at pH 6.1. ATP could also chelate Zn(2+) at pH 6.1 because its pKa is about 6.8. Therefore, it was tested whether an ATP depletion affects the acid-induced [Zn(2+) ]i elevations. The ATP depletion was induced by inhibiting mitochondrial and glycolytic ATP production. Interestingly, an almost complete ATP depletion (confirmed using a luciferin/luciferase assay) failed to affect the acid-induced [Zn(2+) ]i increases. These data suggest that the total amount of Zn(2+) accumulated in intracellular ATP-dependent stores (Zn(2+) -ATP complexes and organelles that accumulate Zn(2+) in an ATP-dependent manner) is negligible compared to the amount of Zn(2+) accumulated in the acid-sensitive intracellular ligands. In vitro, upon acidification, Zn(2+) -cysteine complexes release Zn(2+) and ATP chelates the released Zn(2+) . However, in vivo (cultured neurons), an ATP depletion failed to enhance acid-induced [Zn(2+) ]i elevations. These [Zn(2+) ]i elevations were calibrated using a low affinity ratiometric probe FuraZin-1; they reached 2 µM levels and increased to 5 µM when a thiol-reactive agent, N-ethylmaleimide, compromised Zn(2+) binding by cysteines.
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Affiliation(s)
- Lech Kiedrowski
- The Psychiatric Institute, Departments of Psychiatry and Pharmacology, The University of Illinois at Chicago, Chicago, Illinois, USA
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29
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Pinter TBJ, Irvine GW, Stillman MJ. Domain Selection in Metallothionein 1A: Affinity-Controlled Mechanisms of Zinc Binding and Cadmium Exchange. Biochemistry 2015; 54:5006-16. [DOI: 10.1021/acs.biochem.5b00452] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tyler B. J. Pinter
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Gordon W. Irvine
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Martin J. Stillman
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
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30
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Yao S, Flight RM, Rouchka EC, Moseley HNB. A less-biased analysis of metalloproteins reveals novel zinc coordination geometries. Proteins 2015; 83:1470-87. [PMID: 26009987 PMCID: PMC4539273 DOI: 10.1002/prot.24834] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/05/2015] [Accepted: 05/17/2015] [Indexed: 11/13/2022]
Abstract
Zinc metalloproteins are involved in many biological processes and play crucial biochemical roles across all domains of life. Local structure around the zinc ion, especially the coordination geometry (CG), is dictated by the protein sequence and is often directly related to the function of the protein. Current methodologies in characterizing zinc metalloproteins' CG consider only previously reported CG models based mainly on nonbiological chemical context. Exceptions to these canonical CG models are either misclassified or discarded as “outliers.” Thus, we developed a less‐biased method that directly handles potential exceptions without pre‐assuming any CG model. Our study shows that numerous exceptions could actually be further classified and that new CG models are needed to characterize them. Also, these new CG models are cross‐validated by strong correlation between independent structural and functional annotation distance metrics, which is partially lost if these new CGs models are ignored. Furthermore, these new CG models exhibit functional propensities distinct from the canonical CG models. Proteins 2015; 83:1470–1487. © 2015 The Authors. Proteins: Structure, Function, and Bioinformatics Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Sen Yao
- School of Interdisciplinary and Graduate Studies, University of Louisville, Louisville, Kentucky, 40292.,Department of Computer Engineering and Computer Science, University of Louisville, Louisville, Kentucky, 40292
| | - Robert M Flight
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, 40356.,Markey Cancer Center, University of Kentucky, Lexington, Kentucky, 40356.,Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, Kentucky, 40356
| | - Eric C Rouchka
- School of Interdisciplinary and Graduate Studies, University of Louisville, Louisville, Kentucky, 40292.,Department of Computer Engineering and Computer Science, University of Louisville, Louisville, Kentucky, 40292
| | - Hunter N B Moseley
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, 40356.,Markey Cancer Center, University of Kentucky, Lexington, Kentucky, 40356.,Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, Kentucky, 40356
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31
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Alies B, Wiener JD, Franz KJ. A prochelator peptide designed to use heterometallic cooperativity to enhance metal ion affinity. Chem Sci 2015; 6:3606-3610. [PMID: 29511523 PMCID: PMC5659173 DOI: 10.1039/c5sc00602c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 04/22/2015] [Indexed: 12/27/2022] Open
Abstract
A peptide has been designed so that its chelating affinity for one type of metal ion regulates its affinity for a second, different type of metal ion. The prochelator peptide (PCP), which is a fusion of motifs evocative of calcium loops and zinc fingers, forms a 1 : 2 Zn : peptide complex at pH 7.4 that increases its affinity for Zn2+ ∼3-fold in the presence of Tb3+ (log β2 from 13.8 to 14.3), while the 1 : 1 luminescent complex with Tb3+ is brighter, longer lived, and 20-fold tighter in the presence of Zn2+ (log K from 6.2 to 7.5). This unique example of cooperative, heterometallic allostery in a biologically compatible construct suggests the possibility of designing conditionally active metal-binding agents that could respond to dynamic changes in cellular metal status.
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Affiliation(s)
- Bruno Alies
- Department of Chemistry , Duke University , Durham , North Carolina 27708 , USA .
| | - Jacob D Wiener
- Department of Chemistry , Duke University , Durham , North Carolina 27708 , USA .
| | - Katherine J Franz
- Department of Chemistry , Duke University , Durham , North Carolina 27708 , USA .
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32
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Abstract
Mammalian metallothioneins (MTs) comprise a Zn3Cys9 cluster in the β domain and a Zn4Cys11 cluster in the α domain. They play a crucial role in storing and donating Zn(2+) ions to target metalloproteins and have been implicated in several diseases, thus understanding how MTs release Zn(2+) is of widespread interest. In this work, we present a strategy to compute the free energy for releasing Zn(2+) from MTs using a combination of classical molecular dynamics (MD) simulations, quantum-mechanics/molecular-mechanics (QM/MM) minimizations, and continuum dielectric calculations. The methodology is shown to reproduce the experimental observations that (1) the Zn-binding sites do not have equal Zn(2+) affinity and (2) the isolated β domain is thermodynamically less stable and releases Zn(2+) faster with oxidizing agents than the isolated α domain. It was used to compute the free energies for Zn(2+) release from the metal cluster in the absence and presence of the protein matrix (protein architecture and coupled protein-water interactions) to yield the respective disulfide-bonded product. The results show the importance of the protein matrix as well as protein dynamics and coupled conformational changes in accounting for the differential Zn(2+)-releasing propensity of the two domains with oxidizing agents.
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Affiliation(s)
- C Satheesan Babu
- Institute of Biomedical Sciences, Academia Sinica , Taipei 115, Taiwan , R.O.C
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33
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Kukic I, Kelleher SL, Kiselyov K. Zn2+ efflux through lysosomal exocytosis prevents Zn2+-induced toxicity. J Cell Sci 2014; 127:3094-103. [PMID: 24829149 DOI: 10.1242/jcs.145318] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Zn(2+) is an essential micronutrient and an important ionic signal whose excess, as well as scarcity, is detrimental to cells. Free cytoplasmic Zn(2+) is controlled by a network of Zn(2+) transporters and chelating proteins. Recently, lysosomes became the focus of studies in Zn(2+) transport, as they were shown to play a role in Zn(2+)-induced toxicity by serving as Zn(2+) sinks that absorb Zn(2+) from the cytoplasm. Here, we investigated the impact of the lysosomal Zn(2+) sink on the net cellular Zn(2+) distribution and its role in cell death. We found that lysosomes played a cytoprotective role during exposure to extracellular Zn(2+). Such a role required lysosomal acidification and exocytosis. Specifically, we found that the inhibition of lysosomal acidification using Bafilomycin A1 (Baf) led to a redistribution of Zn(2+) pools and increased apoptosis. Additionally, the inhibition of lysosomal exocytosis through knockdown (KD) of the lysosomal SNARE proteins VAMP7 and synaptotagmin VII (SYT7) suppressed Zn(2+) secretion and VAMP7 KD cells had increased apoptosis. These data show that lysosomes play a central role in Zn(2+) handling, suggesting that there is a new Zn(2+) detoxification pathway.
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Affiliation(s)
- Ira Kukic
- The Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Shannon L Kelleher
- The Department of Nutritional Sciences, College of Health and Human Development, The Pennsylvania State University, University Park, PA 16802, USA Department of Surgery, Penn State Hershey Medical Center, Hershey, PA 17033, USA Department of Cellular and Molecular Physiology, Penn State Hershey Medical Center, Hershey, PA 17033, USA
| | - Kirill Kiselyov
- The Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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34
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Kiedrowski L. Proton-dependent zinc release from intracellular ligands. J Neurochem 2014; 130:87-96. [PMID: 24606401 DOI: 10.1111/jnc.12712] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/01/2014] [Accepted: 03/06/2014] [Indexed: 11/30/2022]
Abstract
In cultured cortical and hippocampal neurons when intracellular pH drops from 6.6 to 6.1, yet unclear intracellular stores release micromolar amounts of Zn(2+) into the cytosol. Mitochondria, acidic organelles, and/or intracellular ligands could release this Zn(2+) . Although exposure to the protonophore FCCP precludes reloading of the mitochondria and acidic organelles with Zn(2+) , FCCP failed to compromise the ability of the intracellular stores to repeatedly release Zn(2+) . Therefore, Zn(2+) -releasing stores were not mitochondria or acidic organelles but rather intracellular Zn(2+) ligands. To test which ligands might be involved, the rate of acid-induced Zn(2+) release from complexes with cysteine, glutathione, histidine, aspartate, glutamate, glycine, and carnosine was investigated; [Zn(2+) ] was monitored in vitro using the ratiometric Zn(2+) -sensitive fluorescent probe FuraZin-1. Carnosine failed to chelate Zn(2+) but did chelate Cu(2+) ; the remaining ligands chelated Zn(2+) and upon acidification were releasing it into the medium. However, when pH was decreasing from 6.6 to 6.1, only zinc-cysteine complexes rapidly accelerated the rate of Zn(2+) release. The zinc-cysteine complexes also released Zn(2+) when a histidine-modifying agent, diethylpyrocarbonate, was applied at pH 7.2. Since the cytosolic zinc-cysteine complexes can contain micromolar amounts of Zn(2+) , these complexes may represent the stores responsible for an acid-induced intracellular Zn(2+) release. This study aimed at identifying intracellular stores which release Zn(2+) when pHi drops from 6.6 to 6.1. It was found that these stores are not mitochondria or acidic organelles, but rather intracellular Zn(2+) ligands. When the pH was decreasing from 6.6 to 6.1, only zinc-cysteine complexes showed a rapid acceleration in the rate of Zn(2+) release. Therefore, the stores responsible for an acid-induced intracellular Zn(2+) release in neurons may be the cytosolic zinc-cysteine complexes.
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Affiliation(s)
- Lech Kiedrowski
- Departments of Psychiatry and Pharmacology, The Psychiatric Institute, The University of Illinois at Chicago, Chicago, Illinois, USA
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35
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Mechanisms of rapid reactive oxygen species generation in response to cytosolic Ca2+ or Zn2+ loads in cortical neurons. PLoS One 2013; 8:e83347. [PMID: 24340096 PMCID: PMC3858366 DOI: 10.1371/journal.pone.0083347] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 11/01/2013] [Indexed: 12/16/2022] Open
Abstract
Excessive “excitotoxic” accumulation of Ca2+ and Zn2+ within neurons contributes to neurodegeneration in pathological conditions including ischemia. Putative early targets of these ions, both of which are linked to increased reactive oxygen species (ROS) generation, are mitochondria and the cytosolic enzyme, NADPH oxidase (NOX). The present study uses primary cortical neuronal cultures to examine respective contributions of mitochondria and NOX to ROS generation in response to Ca2+ or Zn2+ loading. Induction of rapid cytosolic accumulation of either Ca2+ (via NMDA exposure) or Zn2+ (via Zn2+/Pyrithione exposure in 0 Ca2+) caused sharp cytosolic rises in these ions, as well as a strong and rapid increase in ROS generation. Inhibition of NOX activation significantly reduced the Ca2+-induced ROS production with little effect on the Zn2+- triggered ROS generation. Conversely, dissipation of the mitochondrial electrochemical gradient increased the cytosolic Ca2+ or Zn2+ rises caused by these exposures, consistent with inhibition of mitochondrial uptake of these ions. However, such disruption of mitochondrial function markedly suppressed the Zn2+-triggered ROS, while partially attenuating the Ca2+-triggered ROS. Furthermore, block of the mitochondrial Ca2+ uniporter (MCU), through which Zn2+ as well as Ca2+ can enter the mitochondrial matrix, substantially diminished Zn2+ triggered ROS production, suggesting that the ROS generation occurs specifically in response to Zn2+ entry into mitochondria. Finally, in the presence of the sulfhydryl-oxidizing agent 2,2'-dithiodipyridine, which impairs Zn2+ binding to cytosolic metalloproteins, far lower Zn2+ exposures were able to induce mitochondrial Zn2+ uptake and consequent ROS generation. Thus, whereas rapid acute accumulation of Zn2+ and Ca2+ each can trigger injurious ROS generation, Zn2+ entry into mitochondria via the MCU may do so with particular potency. This may be of particular relevance to conditions like ischemia in which cytosolic Zn2+ buffering is impaired due to acidosis and oxidative stress.
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36
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Loebus J, Leitenmaier B, Meissner D, Braha B, Krauss GJ, Dobritzsch D, Freisinger E. The major function of a metallothionein from the aquatic fungus Heliscus lugdunensis is cadmium detoxification. J Inorg Biochem 2013; 127:253-60. [DOI: 10.1016/j.jinorgbio.2013.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 05/31/2013] [Accepted: 06/02/2013] [Indexed: 10/26/2022]
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37
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Mato S, Sánchez-Gómez MV, Bernal-Chico A, Matute C. Cytosolic zinc accumulation contributes to excitotoxic oligodendroglial death. Glia 2013; 61:750-64. [PMID: 23440871 DOI: 10.1002/glia.22470] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 12/27/2012] [Indexed: 01/01/2023]
Abstract
Dyshomeostasis of cytosolic Zn(2+) is a critical mediator of neuronal damage during excitotoxicity. However, the role of this cation in oligodendrocyte pathophysiology is not well understood. The current study examined the contribution of Zn(2+) deregulation to oligodendrocyte injury mediated by AMPA receptors. Oligodendrocytes loaded with the Zn(2+)-selective indicator FluoZin-3 responded to mild stimulation of AMPA receptors with fast cytosolic Zn(2+) rises that resulted from intracellular release, as they were not blocked by the extracellular Zn(2+) chelator Ca-EDTA. Pharmacological experiments suggested that AMPA-induced Zn(2+) mobilization depends on cytosolic Ca(2+) accumulation, arises from mitochondria and protein-bound pools, and is triggered by mechanisms that do not involve the generation of reactive oxygen species. Moreover, intracellular Zn(2+) rises resulting from AMPA receptor activation seem to be promoted by Ca(2+)-dependent cytosolic acidification. Addition of the cell-permeable Zn(2+) chelator TPEN significantly reduced mitochondrial membrane depolarization, reactive oxygen species production, and cell death by sub-maximal activation of AMPA receptors both in vitro and in situ, suggesting that Zn(2+) deregulation is an important mediator of oligodendrocyte excitotoxicity. These data provide evidence that strategies aimed at maintaining Zn(2+) homeostasis may be useful for the treatment of disorders in which excitotoxicity is an important trigger of oligodendroglial death.
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Affiliation(s)
- Susana Mato
- Departamento de Neurociencias, Universidad del País Vasco-UPV/EHU, E-48940 Leioa, Spain.
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38
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Blindauer CA. Lessons on the critical interplay between zinc binding and protein structure and dynamics. J Inorg Biochem 2013; 121:145-55. [PMID: 23376625 DOI: 10.1016/j.jinorgbio.2013.01.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 01/08/2013] [Accepted: 01/08/2013] [Indexed: 02/05/2023]
Abstract
Zinc is one of the most important micronutrients for virtually all living organisms, and hence, it is important to understand the molecular mechanisms for its homeostasis. Besides proteins involved in transmembrane transport, both extra- and intracellular zinc-binding proteins play important roles in the respective metabolic networks. Important examples for extracellular zinc transporters are mammalian serum albumins, and for intracellular zinc handling, certain metallothioneins are of relevance. The availability of protein structures including relevant metal binding sites is a fundamental prerequisite to decipher the mechanisms that govern zinc binding dynamics in these proteins, but their determination can prove to be surprisingly challenging. Due to the spectroscopic silence of Zn(2+), combinations of biophysical techniques including electrospray ionisation mass spectrometry (ESI-MS) and multinuclear NMR, isothermal titration calorimetry (ITC) and extended X-ray absorption fine structure (EXAFS) spectroscopy, coupled with site-directed mutagenesis and molecular modelling have proven to be valuable approaches to understand not only the zinc-binding properties of metallothioneins and albumins, but also the influence of other physiologically relevant competing agents. These studies have demonstrated why the bacterial metallothionein SmtA contains a site inert towards exchange with Cd(2+), why the plant metallothionein EC from wheat is partially unfolded in the presence of Cd(2+), and how fatty acids impact on the zinc-binding ability of mammalian serum albumins.
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39
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Peroza EA, dos Santos Cabral A, Wan X, Freisinger E. Metal ion release from metallothioneins: proteolysis as an alternative to oxidation. Metallomics 2013; 5:1204-14. [DOI: 10.1039/c3mt00079f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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El Muayed M, Raja MR, Zhang X, MacRenaris KW, Bhatt S, Chen X, Urbanek M, O'Halloran TV, Lowe WL. Accumulation of cadmium in insulin-producing β cells. Islets 2012; 4:405-16. [PMID: 23466887 PMCID: PMC3605169 DOI: 10.4161/isl.23101] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Evidence suggests that chronic low level cadmium exposure impairs the function of insulin-producing β cells and may be associated with type-2 diabetes mellitus. Herein, we describe the cadmium content in primary human islets and define the uptake kinetics and effects of environmentally relevant cadmium concentrations in cultured β cells. The average cadmium content in islets from 10 non-diabetic human subjects was 29 ± 7 nmol/g protein (range 7 to 72 nmol/g protein). Exposure of the β-cell line MIN6 to CdCl 2 concentrations between 0.1 and 1.0 µmol/L resulted in a dose- and time-dependent uptake of cadmium over 72 h. This uptake resulted in an induction of metallthionein expression, likely enhancing cellular cadmium accumulation. Furthermore, cadmium accumulation resulted in an inhibition of glucose stimulated insulin secretion in MIN6 cells and primary mouse islets. Our results indicate that this impairment in β-cell function is not due to an increase in cell death or due to an increase in oxidative stress. We conclude that mouse β cells accumulate cadmium in a dose- and time-dependent manner over a prolonged time course at environmentally relevant concentrations. This uptake leads to a functional impairment of β-cell function without significant alterations in cell viability, expression of genes important for β-cell function or increase in oxidative stress.
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Affiliation(s)
- Malek El Muayed
- Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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41
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Frazzini V. Synaptic physiology revised: think zinc! FUTURE NEUROLOGY 2012. [DOI: 10.2217/fnl.12.40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The last few years have seen a dramatic increase in our understanding of the Zn2+ modulatory role in the physiological functioning of the CNS. The availability of new experimental tools, such as the combination of new microscopy techniques with electrophysiological recordings, along with new selective fluorescent probes and chelators has started a revolution in Zn2+ neurobiology. Zn2+ has emerged as a versatile signaling molecule involved in numerous critical neuronal functions spanning from synaptic transmission and plasticity to neuronal differentiation and death.
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Affiliation(s)
- Valerio Frazzini
- Molecular Neurology Unit, Center of Excellence on Aging (Ce.S.I.), University G. D’Annunzio, Chieti-Pescara, Italy
- Department of Neuroscience & Imaging, University G. D’Annunzio, Chieti-Pescara, Italy
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42
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Abstract
In neurons exposed to glutamate, Ca²⁺ influx triggers intracellular Zn²⁺ release via an as yet unclear mechanism. As glutamate induces a Ca²⁺-dependent cytosolic acidification, the present work tested the relationships among intracellular Ca²⁺ concentration ([Ca²⁺](i)), intracellular pH (pH(i) ), and [Zn²⁺](i). Cultured hippocampal neurons were exposed to glutamate and glycine (Glu/Gly), while [Zn²⁺](i), [Ca²⁺](i) and pH(i) were monitored using FluoZin-3, Fura2-FF, and 2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein, respectively. Glu/Gly applications decreased pH(i) to 6.1 and induced intracellular Zn²⁺ release in a Ca²⁺-dependent manner, as expected. The pH(i) drop reduced the affinity of FluoZin-3 and Fura-2-FF for Zn²⁺. The rate of Glu/Gly-induced [Zn²⁺](i) increase was not correlated with the rate of [Ca²⁺](i) increase. Instead, the extent of [Zn²⁺](i) elevations corresponded well to the rate of pH(i) drop. Namely, [Zn²⁺](i) increased more in more highly acidified neurons. Inhibiting the mechanisms responsible for the Ca²⁺-dependent pH(i) drop (plasmalemmal Ca²⁺ pump and mitochondria) counteracted the Glu/Gly-induced intracellular Zn²⁺ release. Alkaline pH (8.5) suppressed Glu/Gly-induced intracellular Zn²⁺ release whereas acidic pH (6.0) enhanced it. A pH(i) drop to 6.0 (without any Ca²⁺ influx or glutamate receptor activation) led to intracellular Zn²⁺ release; the released Zn²⁺ (free Zn²⁺ plus Zn²⁺) bound to Fura-2FF and FluoZin-3) reached 1 μM.
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Affiliation(s)
- Lech Kiedrowski
- Departments of Psychiatry and Pharmacology, The Psychiatric Institute, The University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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43
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Abstract
Our understanding of the roles played by zinc in the physiological and pathological functioning of the brain is rapidly expanding. The increased availability of genetically modified animal models, selective zinc-sensitive fluorescent probes, and novel chelators is producing a remarkable body of exciting new data that clearly establishes this metal ion as a key modulator of intracellular and intercellular neuronal signaling. In this Mini-Symposium, we will review and discuss the most recent findings that link zinc to synaptic function as well as the injurious effects of zinc dyshomeostasis within the context of neuronal death associated with major human neurological disorders, including stroke, epilepsy, and Alzheimer's disease.
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44
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Greisen P, Jespersen JB, Kepp KP. Metallothionein Zn2+- and Cu2+-clusters from first-principles calculations. Dalton Trans 2011; 41:2247-56. [PMID: 22183579 DOI: 10.1039/c1dt11785h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Detailed electronic structures of Zn(II) and Cu(II) clusters from metallothioneins (MT) have been obtained using density functional theory (DFT), in order to investigate how oxidative stress-caused Cu(II) intermediates affect Zn-binding to MT and cooperatively lead to Cu(I)MT. The inferred accuracy is ∼0.02-0.03 Å for metal-thiolate bond lengths for the models that are the most realistic MT models so far studied by DFT. We find terminal Zn-S and Cu-S bond lengths of 2.35-2.38 Å and 2.30-2.34 Å, whereas bridging M-S bonds are 0.05-0.11 Å longer. This electronic effect is also reflected in changes in electron density on bridging sulfurs. Various imposed backbone constraints quantify the sensitivity of cluster electronic structure towards protein conformational changes. The large negative charge densities of the clusters are central to MT function, and the smaller β-clusters are more prone to modification. Oxidative stress-associated Cu(II) binding weakens the Zn-S bonds and is thus likely to impair the Zn(II) transfer function of MTs, providing a mechanism for cooperative Cu(II) binding leading to loss of Zn(II) and dysfunctional Cu(I)MT clusters.
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Affiliation(s)
- Per Greisen
- Technical University of Denmark, DTU Physics, 2800, Kongens Lyngby, Denmark
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Kepp KP. Full quantum-mechanical structure of the human protein Metallothionein-2. J Inorg Biochem 2011; 107:15-24. [PMID: 22178664 DOI: 10.1016/j.jinorgbio.2011.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 11/02/2011] [Accepted: 11/08/2011] [Indexed: 01/18/2023]
Abstract
Metallothioneins (MT) are small, metal-binding proteins with diverse functions related to metal ion homeostasis. This paper presents the full 384-388-atom structures of the two native Zn(II)- and the Cd(II)-containing domains of human MT2, optimized with density functional theory. The presented structures are accurate to ~0.03 Å for bond lengths and thus provide new physical insight into the detailed electronic structures of MTs, in particular with accurate accounts of bridging vs. terminal bonds not available from NMR or EXAFS. The MT protein enhances the asymmetry, as compared to the protein-free clusters, causing a hierarchy in binding that most likely allows MTs to transfer ions to multiple targets in vivo. The protein polarization is substantial and occurs primarily via the terminal sulfurs, a key mechanism in providing domain-specific electronic structures. The β-domain polarizes its smaller cluster less on average, due to its less polarizable, higher negative charge density, as reflected in longer MS bond lengths and smaller bond orders. This may explain why MT2β is more reactive and dynamic and why MTs have evolved two different-size, asymmetric domains with different metal binding affinities fit for different molecular targets of metal ion transfer.
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Affiliation(s)
- Kasper P Kepp
- Technical University of Denmark, DTU Chemistry, DK-2800 Kgs. Lyngby, Denmark.
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Freisinger E. Structural features specific to plant metallothioneins. J Biol Inorg Chem 2011; 16:1035-45. [PMID: 21688177 DOI: 10.1007/s00775-011-0801-z] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 06/06/2011] [Indexed: 11/26/2022]
Abstract
The metallothionein (MT) superfamily combines a large variety of small cysteine-rich proteins from nearly all phyla of life that have the ability to coordinate various transition metal ions, including Zn(II), Cd(II), and Cu(I). The members of the plant MT family are characterized by great sequence diversity, requiring further subdivision into four subfamilies. Very peculiar and not well understood is the presence of rather long cysteine-free amino acid linkers between the cysteine-rich regions. In light of the distinct differences in sequence to MTs from other families, it seems obvious to assume that these differences will also be manifested on the structural level. This was already impressively demonstrated with the elucidation of the three-dimensional structure of the wheat E(c)-1 MT, which revealed two metal cluster arrangements previously unprecedented for any MT. However, as this structure is so far the only one available for the plant MT family, other sources of information are in high demand. In this review the focus is thus set on any structural features known, deduced, or assumed for the plant MT proteins. This includes the determination of secondary structural elements by circular dichroism, IR, and Raman spectroscopy, the analysis of the influence of the long linker regions, and the evaluation of the spatial arrangement of the sequence separated cysteine-rich regions with the aid of, e.g., limited proteolytic digestion. In addition, special attention is paid to the contents of divalent metal ions as the metal ion to cysteine ratios are important for predicting and understanding possible metal-thiolate cluster structures.
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Affiliation(s)
- Eva Freisinger
- Institute of Inorganic Chemistry, University of Zurich, 8057, Zurich, Switzerland.
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Wang Q, Xu J, Chai B, Liang A, Wang W. Functional comparison of metallothioneins MTT1 and MTT2 from Tetrahymena thermophila. Arch Biochem Biophys 2011; 509:170-6. [DOI: 10.1016/j.abb.2011.02.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/11/2011] [Accepted: 02/16/2011] [Indexed: 11/30/2022]
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Tuncay E, Bilginoglu A, Sozmen NN, Zeydanli EN, Ugur M, Vassort G, Turan B. Intracellular free zinc during cardiac excitation-contraction cycle: calcium and redox dependencies. Cardiovasc Res 2010; 89:634-42. [PMID: 21062918 DOI: 10.1093/cvr/cvq352] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
AIMS Zinc exists in biological systems as bound and histochemically reactive free Zn(2+). It is an essential structural constituent of many proteins, including enzymes from cellular signalling pathways, in which it functions as a signalling molecule. In cardiomyocytes at rest, Zn(2+) concentration is in the nanomolar range. Very little is known about precise mechanisms controlling the intracellular distribution of Zn(2+) and its variations during cardiac function. METHODS AND RESULTS Live-cell detection of intracellular Zn(2+) has become feasible through the recent development of Zn(2+)-sensitive and -selective fluorophores able to distinguish Zn(2+) from Ca(2+). Here, in freshly isolated rat cardiomyocytes, we investigated the rapid changes in Zn(2+) homeostasis using the Zn(2+)-specific fluorescent dye, FluoZin-3, in comparison to Ca(2+)-dependent fluo-3 fluorescence. Zn(2+) sparks and Zn(2+) transients, in quiescent and electrically stimulated cardiomyocytes, respectively, were visualized in a similar manner to known rapid Ca(2+) changes. Both Zn(2+) sparks and Zn(2+) transients required Ca(2+) entry. Inhibiting the sarcoplasmic reticulum Ca(2+) release or increasing the Ca(2+) load in a low-Na(+) solution suppressed or increased Zn(2+) movements, respectively. Mitochondrial inhibitors slightly reduced both Zn(2+) sparks and Zn(2+) transients. Oxidation by H₂O₂ facilitated and acidic pH inhibited the Ca(2+)-dependent Zn(2+) release. CONCLUSION It is proposed that Zn(2+) release during the cardiac cycle results mostly from intracellular free Ca(2+) increase, triggering production of reactive oxygen species that induce changes in metal-binding properties of metallothioneins and other redox-active proteins, aside from ionic exchange on these proteins.
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Affiliation(s)
- Erkan Tuncay
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara 06100, Turkey
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Ngu TT, Dryden MD, Stillman MJ. Arsenic transfer between metallothionein proteins at physiological pH. Biochem Biophys Res Commun 2010; 401:69-74. [DOI: 10.1016/j.bbrc.2010.09.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 09/04/2010] [Indexed: 10/19/2022]
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Huang ZX, Liu F, Zheng Q, Yu WH. Zinc Transfer Kinetics of Metallothioneins and Their Fragments with Apo-carbonic Anhydrase. CHINESE J CHEM 2010. [DOI: 10.1002/cjoc.20010190506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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