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Peris-Díaz MD, Orzeł A, Wu S, Mosna K, Barran PE, Krężel A. Combining Native Mass Spectrometry and Proteomics to Differentiate and Map the Metalloform Landscape in Metallothioneins. J Proteome Res 2024; 23:3626-3637. [PMID: 38993068 PMCID: PMC11301679 DOI: 10.1021/acs.jproteome.4c00271] [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: 04/03/2024] [Revised: 06/27/2024] [Accepted: 07/03/2024] [Indexed: 07/13/2024]
Abstract
Within the intricate landscape of the proteome, approximately 30% of all proteins bind metal ions. This repertoire is even larger when considering all the different forms of a protein, known as proteoforms. Here, we propose the term "metalloforms" to refer to different structural or functional variations of a protein resulting from the binding of various hetero- or homogeneous metal ions. Using human Cu(I)/Zn(II)-metallothionein-3 as a representative model, we developed a chemical proteomics strategy to simultaneously differentiate and map Zn(II) and Cu(I) metal binding sites. In the first labeling step, N-ethylmaleimide reacts with Cysteine (Cys), resulting in the dissociation of all Zn(II) ions while Cu(I) remains bound to the protein. In the second labeling step, iodoacetamide is utilized to label Cu(I)-bound Cys residues. Native mass spectrometry (MS) was used to determine the metal/labeling protein stoichiometries, while bottom-up/top-down MS was used to map the Cys-labeled residues. Next, we used a developed methodology to interrogate an isolated rabbit liver metallothionein fraction containing three metallothionein-2 isoforms and multiple Cd(II)/Zn(II) metalloforms. The approach detailed in this study thus holds the potential to decode the metalloproteoform diversity within other proteins.
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Affiliation(s)
- Manuel David Peris-Díaz
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, Wrocław 50-383, Poland
- Michael
Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Alicja Orzeł
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, Wrocław 50-383, Poland
| | - Sylwia Wu
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, Wrocław 50-383, Poland
| | - Karolina Mosna
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, Wrocław 50-383, Poland
| | - Perdita E. Barran
- Michael
Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Artur Krężel
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, Wrocław 50-383, Poland
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2
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Nabatilan A, Thomas Morgan M, Netzer S, Fahrni CJ. Selective removal of copper from complex biological media with an agarose-immobilized high-affinity PSP ligand. J Biol Inorg Chem 2024; 29:531-540. [PMID: 39066798 DOI: 10.1007/s00775-024-02065-x] [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: 04/10/2024] [Accepted: 06/20/2024] [Indexed: 07/30/2024]
Abstract
The elucidation of metal-dependent biological processes requires selective reagents for manipulating metal ion levels within biological solutions such as growth media or cell lysates. To this end, we immobilized a phosphine sulfide-stabilized phosphine (PSP) ligand on agarose to create a resin for the selective removal of copper from chemically complex biological media through simple filtration or centrifugation. Comprised of a conformationally preorganized phenylene-bridged backbone, the PSP-ligand binds Cu(I) with a 1:1 stoichiometry and exhibits a pH-independent Cu(I) dissociation constant in the low zeptomolar range. Neither Zn(II), Fe(II), nor Mn(II) interact with the ligand at millimolar concentrations, thus offering a much-improved selectivity towards copper over other commonly employed solid-supported chelators such as Chelex 100. As revealed by X-ray fluorescence elemental analysis, the immobilized chelator effectively removes copper from cell culture growth media and cell lysate isolated from mouse fibroblasts. In addition to preparing copper-depleted media or cell lysates for biological studies, PSP-immobilized ligands might prove equally useful for applications in radiochemistry, materials science, and environmental science.
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Affiliation(s)
- Arielle Nabatilan
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA, 30332, USA
| | - M Thomas Morgan
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA, 30332, USA
| | - Sara Netzer
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA, 30332, USA
| | - Christoph J Fahrni
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA, 30332, USA.
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3
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Bouraguba M, Schmitt AM, Yelisetty VS, Vileno B, Melin F, Glattard E, Orvain C, Lebrun V, Raibaut L, Ilbert M, Bechinger B, Hellwig P, Gaiddon C, Sour A, Faller P. Quest for a stable Cu-ligand complex with a high catalytic activity to produce reactive oxygen species. Metallomics 2024; 16:mfae020. [PMID: 38614957 DOI: 10.1093/mtomcs/mfae020] [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: 03/21/2024] [Accepted: 04/12/2024] [Indexed: 04/15/2024]
Abstract
Metal ion-catalyzed overproduction of reactive oxygen species (ROS) is believed to contribute significantly to oxidative stress and be involved in several biological processes, from immune defense to development of diseases. Among the essential metal ions, copper is one of the most efficient catalysts in ROS production in the presence of O2 and a physiological reducing agent such as ascorbate. To control this chemistry, Cu ions are tightly coordinated to biomolecules. Free or loosely bound Cu ions are generally avoided to prevent their toxicity. In the present report, we aim to find stable Cu-ligand complexes (Cu-L) that can efficiently catalyze the production of ROS in the presence of ascorbate under aerobic conditions. Thermodynamic stability would be needed to avoid dissociation in the biological environment, and high ROS catalysis is of interest for applications as antimicrobial or anticancer agents. A series of Cu complexes with the well-known tripodal and tetradentate ligands containing a central amine linked to three pyridyl-alkyl arms of different lengths were investigated. Two of them with mixed arm length showed a higher catalytic activity in the oxidation of ascorbate and subsequent ROS production than Cu salts in buffer, which is an unprecedented result. Despite these high catalytic activities, no increased antimicrobial activity toward Escherichia coli or cytotoxicity against eukaryotic AGS cells in culture related to Cu-L-based ROS production could be observed. The potential reasons for discrepancy between in vitro and in cell data are discussed.
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Affiliation(s)
- Merwan Bouraguba
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Adeline M Schmitt
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Venkata Suseela Yelisetty
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Bertrand Vileno
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Frédéric Melin
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Elise Glattard
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Christophe Orvain
- Inserm UMR_S 1113, Université de Strasbourg, 3 avenue Molière, 67200 Strasbourg, France
| | - Vincent Lebrun
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Laurent Raibaut
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Marianne Ilbert
- Aix-Marseille Université, CNRS, Bioénergétique et Ingénierie des Protéines (BIP), UMR 7281, IMM, Marseille, France
| | - Burkhard Bechinger
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
- Institut Universitaire de France (IUF), 1 rue Descartes, 75231 Paris, France
| | - Petra Hellwig
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France
- Institut Universitaire de France (IUF), 1 rue Descartes, 75231 Paris, France
| | - Christian Gaiddon
- Inserm UMR_S 1113, Université de Strasbourg, 3 avenue Molière, 67200 Strasbourg, France
| | - Angélique Sour
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Peter Faller
- Institut de Chimie, UMR 7177, Université́ de Strasbourg, CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
- Institut Universitaire de France (IUF), 1 rue Descartes, 75231 Paris, France
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Peris-Díaz MD, Wu S, Mosna K, Liggett E, Barkhanskiy A, Orzeł A, Barran P, Krężel A. Structural Characterization of Cu(I)/Zn(II)-metallothionein-3 by Ion Mobility Mass Spectrometry and Top-Down Mass Spectrometry. Anal Chem 2023; 95:10966-10974. [PMID: 37440218 PMCID: PMC10372872 DOI: 10.1021/acs.analchem.3c00989] [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: 03/06/2023] [Accepted: 06/29/2023] [Indexed: 07/14/2023]
Abstract
Mammalian zinc metallothionein-3 (Zn7MT3) plays an important role in protecting against copper toxicity by scavenging free Cu(II) ions or removing Cu(II) bound to β-amyloid and α-synuclein. While previous studies reported that Zn7MT3 reacts with Cu(II) ions to form Cu(I)4Zn(II)4MT3ox containing two disulfides (ox), the precise localization of the metal ions and disulfides remained unclear. Here, we undertook comprehensive structural characterization of the metal-protein complexes formed by the reaction between Zn7MT3 and Cu(II) ions using native ion mobility mass spectrometry (IM-MS). The complex formation mechanism was found to involve the disassembly of Zn3S9 and Zn4S11 clusters from Zn7MT3 and reassembly into Cu(I)xZn(II)yMT3ox complexes rather than simply Zn(II)-to-Cu(I) exchange. At neutral pH, the β-domain was shown to be capable of binding up to six Cu(I) ions to form Cu(I)6Zn(II)4MT3ox, although the most predominant species was the Cu(I)4Zn(II)4MT3ox complex. Under acidic conditions, four Zn(II) ions dissociate, but the Cu(I)4-thiolate cluster remains stable, highlighting the MT3 role as a Cu(II) scavenger even at lower than the cytosolic pH. IM-derived collision cross sections (CCS) reveal that Cu(I)-to-Zn(II) swap in Zn7MT3 with concomitant disulfide formation induces structural compaction and a decrease in conformational heterogeneity. Collision-induced unfolding (CIU) experiments estimated that the native-like folded Cu(I)4Zn(II)4MT3ox conformation is more stable than Zn7MT3. Native top-down MS demonstrated that the Cu(I) ions are exclusively bound to the β-domain in the Cu(I)4Zn(II)4MT3ox complex as well as the two disulfides, serving as a steric constraint for the Cu(I)4-thiolate cluster. In conclusion, this study enhances our comprehension of the structure, stability, and dynamics of Cu(I)xZn(II)yMT3ox complexes.
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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
- Michael
Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, 131 Princess Street, Manchester M1 7DN, United
Kingdom
| | - Sylwia Wu
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Karolina Mosna
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Ellen Liggett
- Michael
Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, 131 Princess Street, Manchester M1 7DN, United
Kingdom
| | - Alexey Barkhanskiy
- Michael
Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, 131 Princess Street, Manchester M1 7DN, United
Kingdom
| | - Alicja Orzeł
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Perdita Barran
- Michael
Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, 131 Princess Street, Manchester M1 7DN, United
Kingdom
| | - Artur Krężel
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, 50-383 Wrocław, Poland
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5
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Fan L, Russell DH. An ion mobility-mass spectrometry study of copper-metallothionein-2A: binding sites and stabilities of Cu-MT and mixed metal Cu-Ag and Cu-Cd complexes. Analyst 2023; 148:546-555. [PMID: 36545796 PMCID: PMC9904198 DOI: 10.1039/d2an01556k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The presence of Cu, a highly redox active metal, is known to damage DNA as well as other cellular components, but the adverse effects of cellular Cu can be mitigated by metallothioneins (MT), small cysteine rich proteins that are known to bind to a broad range of metal ions. While metal ion binding has been shown to involve the cysteine thiol groups, the specific ion binding sites are controversial as are the overall structure and stability of the Cu-MT complexes. Here, we report results obtained using nano-electrospray ionization mass spectrometry and ion mobility-mass spectrometry for several Cu-MT complexes and compare our results with those previously reported for Ag-MT complexes. The data include determination of the stoichiometries of the complex (Cui-MT, i = 1-19), and Cu+ ion binding sites for complexes where i = 4, 6, and 10 using bottom-up and top-down proteomics. The results show that Cu+ ions first bind to the β-domain to form Cu4MT then Cu6MT, followed by addition of four Cu+ ions to the α-domain to form a Cu10-MT complex. Stabilities of the Cui-MT (i = 4, 6 and 10) obtained using collision-induced unfolding (CIU) are reported and compared with previously reported CIU data for Ag-MT complexes. We also compare CIU data for mixed metal complexes (CuiAgj-MT, where i + j = 4 and 6 and CuiCdj, where i + j = 4 and 7). Lastly, higher order Cui-MT complexes, where i = 11-19, were also detected at higher concentrations of Cu+ ions, and the metalated product distributions observed are compared to previously reported results for Cu-MT-1A (Scheller et al., Metallomics, 2017, 9, 447-462).
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Affiliation(s)
- Liqi Fan
- Department of Chemistry, Texas A&M University, College Station, TX 77843, USA.
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, TX 77843, USA.
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6
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Bacchella C, Dell'Acqua S, Nicolis S, Monzani E, Casella L. The reactivity of copper complexes with neuronal peptides promoted by catecholamines and its impact on neurodegeneration. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Magrì A, Tabbì G, Naletova I, Attanasio F, Arena G, Rizzarelli E. A Deeper Insight in Metal Binding to the hCtr1 N-terminus Fragment: Affinity, Speciation and Binding Mode of Binuclear Cu 2+ and Mononuclear Ag + Complex Species. Int J Mol Sci 2022; 23:ijms23062929. [PMID: 35328348 PMCID: PMC8953729 DOI: 10.3390/ijms23062929] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/02/2022] [Accepted: 03/05/2022] [Indexed: 01/27/2023] Open
Abstract
Ctr1 regulates copper uptake and its intracellular distribution. The first 14 amino acid sequence of the Ctr1 ectodomain Ctr1(1-14) encompasses the characteristic Amino Terminal Cu2+ and Ni2+ binding motif (ATCUN) as well as the bis-His binding motif (His5 and His6). We report a combined thermodynamic and spectroscopic (UV-vis, CD, EPR) study dealing with the formation of Cu2+ homobinuclear complexes with Ctr1(1-14), the percentage of which is not negligible even in the presence of a small Cu2+ excess and clearly prevails at a M/L ratio of 1.9. Ascorbate fails to reduce Cu2+ when bound to the ATCUN motif, while it reduces Cu2+ when bound to the His5-His6 motif involved in the formation of binuclear species. The histidine diade characterizes the second binding site and is thought to be responsible for ascorbate oxidation. Binding constants and speciation of Ag+ complexes with Ctr1(1-14), which are assumed to mimic Cu+ interaction with N-terminus of Ctr1(1-14), were also determined. A preliminary immunoblot assay evidences that the anti-Ctr1 extracellular antibody recognizes Ctr1(1-14) in a different way from the longer Ctr1(1-25) that encompasses a second His and Met rich domain.
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Affiliation(s)
- Antonio Magrì
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
| | - Giovanni Tabbì
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
| | - Irina Naletova
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
- Consorzio Interuniversitario per la Ricerca dei Metalli nei Sistemi Biologici, Via Ulpiani 27, 70126 Bari, Italy
| | - Francesco Attanasio
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
- Correspondence: (F.A.); (E.R.); Tel.: +39-095-7385070 (E.R.)
| | - Giuseppe Arena
- Department of Chemical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy;
| | - Enrico Rizzarelli
- Institute of Crystallography, National Council of Research, CNR, S.S. Catania, Via P. Gaifami 18, 95126 Catania, Italy; (A.M.); (G.T.); (I.N.)
- Consorzio Interuniversitario per la Ricerca dei Metalli nei Sistemi Biologici, Via Ulpiani 27, 70126 Bari, Italy
- Department of Chemical Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy;
- Correspondence: (F.A.); (E.R.); Tel.: +39-095-7385070 (E.R.)
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Kotuniak R, Bal W. Kinetics of Cu(II) complexation by ATCUN/NTS and related peptides: a gold mine of novel ideas for copper biology. Dalton Trans 2021; 51:14-26. [PMID: 34816848 DOI: 10.1039/d1dt02878b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cu(II)-peptide complexes are intensely studied as models for biological peptides and proteins and for their direct importance in copper homeostasis and dyshomeostasis in human diseases. In particular, high-affinity ATCUN/NTS (amino-terminal copper and nickel/N-terminal site) motifs present in proteins and peptides are considered as Cu(II) transport agents for copper delivery to cells. The information on the affinities and structures of such complexes derived from steady-state methods appears to be insufficient to resolve the mechanisms of copper trafficking, while kinetic studies have recently shown promise in explaining them. Stopped-flow experiments of Cu(II) complexation to ATCUN/NTS peptides revealed the presence of reaction steps with rates much slower than the diffusion limit due to the formation of novel intermediate species. Herein, the state of the field in Cu(II)-peptide kinetics is reviewed in the context of physiological data, leading to novel ideas in copper biology, together with the discussion of current methodological issues.
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Affiliation(s)
- Radosław Kotuniak
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland.
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland.
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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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10
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Redox-Active Metal Ions and Amyloid-Degrading Enzymes in Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22147697. [PMID: 34299316 PMCID: PMC8307724 DOI: 10.3390/ijms22147697] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/11/2021] [Accepted: 07/16/2021] [Indexed: 12/11/2022] Open
Abstract
Redox-active metal ions, Cu(I/II) and Fe(II/III), are essential biological molecules for the normal functioning of the brain, including oxidative metabolism, synaptic plasticity, myelination, and generation of neurotransmitters. Dyshomeostasis of these redox-active metal ions in the brain could cause Alzheimer’s disease (AD). Thus, regulating the levels of Cu(I/II) and Fe(II/III) is necessary for normal brain function. To control the amounts of metal ions in the brain and understand the involvement of Cu(I/II) and Fe(II/III) in the pathogenesis of AD, many chemical agents have been developed. In addition, since toxic aggregates of amyloid-β (Aβ) have been proposed as one of the major causes of the disease, the mechanism of clearing Aβ is also required to be investigated to reveal the etiology of AD clearly. Multiple metalloenzymes (e.g., neprilysin, insulin-degrading enzyme, and ADAM10) have been reported to have an important role in the degradation of Aβ in the brain. These amyloid degrading enzymes (ADE) could interact with redox-active metal ions and affect the pathogenesis of AD. In this review, we introduce and summarize the roles, distributions, and transportations of Cu(I/II) and Fe(II/III), along with previously invented chelators, and the structures and functions of ADE in the brain, as well as their interrelationships.
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11
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Falcone E, Vileno B, Hoang M, Raibaut L, Faller P. A luminescent ATCUN peptide variant with enhanced properties for copper(II) sensing in biological media. J Inorg Biochem 2021; 221:111478. [PMID: 33975250 DOI: 10.1016/j.jinorgbio.2021.111478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/26/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
The measurement of labile CuII in biological samples is fundamental for understanding Cu metabolism and has been emerging as a promising diagnostic marker for Cu-related pathologies such as Wilson's and Alzheimer's diseases. The use of fluorescent chelators may be useful to circumvent separation steps employed by current methods. For this purpose, we recently designed a selective and suited-affinity turn-off luminescent probe based on a peptide bearing the CuII-binding Xxx-Zzz-His (Amino-Terminal CuII- and NiII-binding, ATCUN) motif and a TbIII-DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) complex. Here, we present an analogue probe bearing the ATCUN motif variant Xxx-His-His. This probe showed much faster response in biologically-relevant media and higher stability than the previous motif at low pH. These features could be beneficial to the measurement of dynamic CuII fluctuations and the application in slightly acidic media, such as urine.
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Affiliation(s)
- Enrico Falcone
- Institut de Chimie, UMR 7177, CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France.
| | - Bertrand Vileno
- Institut de Chimie, UMR 7177, CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France; French EPR Federation of Research, Fédération IR-RPE CNRS, 67081 Strasbourg, France.
| | - Mai Hoang
- Institut de Chimie, UMR 7177, CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France; Department of Chemistry, Earlham College, 801 National Road West, Richmond, 47374, Indiana, USA.
| | - Laurent Raibaut
- Institut de Chimie, UMR 7177, CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France.
| | - Peter Faller
- Institut de Chimie, UMR 7177, CNRS, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France.
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12
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Falcone E, Okafor M, Vitale N, Raibaut L, Sour A, Faller P. Extracellular Cu2+ pools and their detection: From current knowledge to next-generation probes. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213727] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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13
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The Aggregation Pattern of Aβ
1–40
is Altered by the Presence of
N
‐Truncated Aβ
4–40
and/or Cu
II
in a Similar Way through Ionic Interactions. Chemistry 2021; 27:2798-2809. [DOI: 10.1002/chem.202004484] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Indexed: 12/19/2022]
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14
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Stefaniak E, Pushie MJ, Vaerewyck C, Corcelli D, Griggs C, Lewis W, Kelley E, Maloney N, Sendzik M, Bal W, Haas KL. Exploration of the Potential Role for Aβ in Delivery of Extracellular Copper to Ctr1. Inorg Chem 2020; 59:16952-16966. [PMID: 33211469 DOI: 10.1021/acs.inorgchem.0c02100] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloid beta (Aβ) peptides are notorious for their involvement in Alzheimer's disease (AD), by virtue of their propensity to aggregate to form oligomers, fibrils, and eventually plaques in the brain. Nevertheless, they appear to be essential for correct neurophysiology on the synaptic level and may have additional functions including antimicrobial activity, sealing the blood-brain barrier, promotion of recovery from brain injury, and even tumor suppression. Aβ peptides are also avid copper chelators, and coincidentally copper is significantly dysregulated in the AD brain. Copper (Cu) is released in significant amounts during calcium signaling at the synaptic membrane. Aβ peptides may have a role in maintaining synaptic Cu homeostasis, including as a scavenger for redox-active Cu and as a chaperone for clearing Cu from the synaptic cleft. Here, we employed the Aβ1-16 and Aβ4-16 peptides as well-established non-aggregating models of major Aβ species in healthy and AD brains, and the Ctr1-14 peptide as a model for the extracellular domain of the human cellular copper transporter protein (Ctr1). With these model peptides and a number of spectroscopic techniques, we investigated whether the Cu complexes of Aβ peptides could provide Ctr1 with either Cu(II) or Cu(I). We found that Aβ1-16 fully and rapidly delivered Cu(II) to Ctr1-14 along the affinity gradient. Such delivery was only partial for the Aβ4-16/Ctr1-14 pair, in agreement with the higher complex stability for the former peptide. Moreover, the reaction was very slow and took ca. 40 h to reach equilibrium under the given experimental conditions. In either case of Cu(II) exchange, no intermediate (ternary) species were present in detectable amounts. In contrast, both Aβ species released Cu(I) to Ctr1-14 rapidly and in a quantitative fashion, but ternary intermediate species were detected in the analysis of XAS data. The results presented here are the first direct evidence of a Cu(I) and Cu(II) transfer between the human Ctr1 and Aβ model peptides. These results are discussed in terms of the fundamental difference between the peptides' Cu(II) complexes (pleiotropic ensemble of open structures of Aβ1-16 vs the rigid closed-ring system of amino-terminal Cu/Ni binding Aβ4-16) and the similarity of their Cu(I) complexes (both anchored at the tandem His13/His14, bis-His motif). These results indicate that Cu(I) may be more feasible than Cu(II) as the cargo for copper clearance from the synaptic cleft by Aβ peptides and its delivery to Ctr1. The arguments in favor of Cu(I) include the fact that cellular Cu export and uptake proteins (ATPase7A/B and Ctr1, respectively) specifically transport Cu(I), the abundance of extracellular ascorbate reducing agent in the brain, and evidence of a potential associative (hand-off) mechanism of Cu(I) transfer that may mirror the mechanisms of intracellular Cu chaperone proteins.
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Affiliation(s)
- Ewelina Stefaniak
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States.,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - M Jake Pushie
- Department of Surgery, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Catherine Vaerewyck
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - David Corcelli
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Chloe Griggs
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Whitney Lewis
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Emma Kelley
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Noreen Maloney
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Madison Sendzik
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Kathryn L Haas
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
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15
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Galler T, Lebrun V, Raibaut L, Faller P, Wezynfeld NE. How trimerization of CTR1 N-terminal model peptides tunes Cu-binding and redox-chemistry. Chem Commun (Camb) 2020; 56:12194-12197. [PMID: 32914794 DOI: 10.1039/d0cc04693k] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Employing peptide-based models of copper transporter 1 (CTR1), we show that the trimeric arrangement of its N-terminus tunes its reactivity with Cu, promoting Cu(ii) reduction and stabilizing Cu(i). Hence, the employed multimeric models of CTR1 provide an important contribution to studies on early steps of Cu uptake by cells.
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Affiliation(s)
- Thibaut Galler
- Institut de Chimie, UMR 7177, CNRS-Universitéde Strasbourg, 4 rue Blaise Pascal, Strasbourg 67000, France.
| | - Vincent Lebrun
- Institut de Chimie, UMR 7177, CNRS-Universitéde Strasbourg, 4 rue Blaise Pascal, Strasbourg 67000, France.
| | - Laurent Raibaut
- Institut de Chimie, UMR 7177, CNRS-Universitéde Strasbourg, 4 rue Blaise Pascal, Strasbourg 67000, France.
| | - Peter Faller
- Institut de Chimie, UMR 7177, CNRS-Universitéde Strasbourg, 4 rue Blaise Pascal, Strasbourg 67000, France.
| | - Nina E Wezynfeld
- Institut de Chimie, UMR 7177, CNRS-Universitéde Strasbourg, 4 rue Blaise Pascal, Strasbourg 67000, France. and Chair of Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw 00-664, Poland.
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16
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Kotuniak R, Strampraad MJF, Bossak‐Ahmad K, Wawrzyniak UE, Ufnalska I, Hagedoorn P, Bal W. Key Intermediate Species Reveal the Copper(II)-Exchange Pathway in Biorelevant ATCUN/NTS Complexes. Angew Chem Int Ed Engl 2020; 59:11234-11239. [PMID: 32267054 PMCID: PMC7383912 DOI: 10.1002/anie.202004264] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Indexed: 01/31/2023]
Abstract
The amino-terminal copper and nickel/N-terminal site (ATCUN/NTS) present in proteins and bioactive peptides exhibits high affinity towards CuII ions and have been implicated in human copper physiology. Little is known, however, about the rate and exact mechanism of formation of such complexes. We used the stopped-flow and microsecond freeze-hyperquenching (MHQ) techniques supported by steady-state spectroscopic and electrochemical data to demonstrate the formation of partially coordinated intermediate CuII complexes formed by glycyl-glycyl-histidine (GGH) peptide, the simplest ATCUN/NTS model. One of these novel intermediates, characterized by two-nitrogen coordination, t1/2 ≈100 ms at pH 6.0 and the ability to maintain the CuII /CuI redox pair is the best candidate for the long-sought reactive species in extracellular copper transport.
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Affiliation(s)
- Radosław Kotuniak
- Department of BiophysicsInstitute of Biochemistry and Biophysics Polish Academy of SciencesPawińskiego 5a02-106WarsawPoland
| | - Marc J. F. Strampraad
- Department of BiotechnologyDelft University of TechnologyVan der Maasweg 92629HZDelftThe Netherlands
| | - Karolina Bossak‐Ahmad
- Department of BiophysicsInstitute of Biochemistry and Biophysics Polish Academy of SciencesPawińskiego 5a02-106WarsawPoland
| | - Urszula E. Wawrzyniak
- Chair of Medical BiotechnologyFaculty of ChemistryWarsaw University of TechnologyNoakowskiego 300-664WarsawPoland
| | - Iwona Ufnalska
- Chair of Medical BiotechnologyFaculty of ChemistryWarsaw University of TechnologyNoakowskiego 300-664WarsawPoland
| | - Peter‐Leon Hagedoorn
- Department of BiotechnologyDelft University of TechnologyVan der Maasweg 92629HZDelftThe Netherlands
| | - Wojciech Bal
- Department of BiophysicsInstitute of Biochemistry and Biophysics Polish Academy of SciencesPawińskiego 5a02-106WarsawPoland
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17
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Kotuniak R, Strampraad MJF, Bossak‐Ahmad K, Wawrzyniak UE, Ufnalska I, Hagedoorn P, Bal W. Key Intermediate Species Reveal the Copper(II)‐Exchange Pathway in Biorelevant ATCUN/NTS Complexes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Radosław Kotuniak
- Department of Biophysics Institute of Biochemistry and Biophysics Polish Academy of Sciences Pawińskiego 5a 02-106 Warsaw Poland
| | - Marc J. F. Strampraad
- Department of Biotechnology Delft University of Technology Van der Maasweg 9 2629 HZ Delft The Netherlands
| | - Karolina Bossak‐Ahmad
- Department of Biophysics Institute of Biochemistry and Biophysics Polish Academy of Sciences Pawińskiego 5a 02-106 Warsaw Poland
| | - Urszula E. Wawrzyniak
- Chair of Medical Biotechnology Faculty of Chemistry Warsaw University of Technology Noakowskiego 3 00-664 Warsaw Poland
| | - Iwona Ufnalska
- Chair of Medical Biotechnology Faculty of Chemistry Warsaw University of Technology Noakowskiego 3 00-664 Warsaw Poland
| | - Peter‐Leon Hagedoorn
- Department of Biotechnology Delft University of Technology Van der Maasweg 9 2629 HZ Delft The Netherlands
| | - Wojciech Bal
- Department of Biophysics Institute of Biochemistry and Biophysics Polish Academy of Sciences Pawińskiego 5a 02-106 Warsaw Poland
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18
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Stefaniak E, Płonka D, Szczerba P, Wezynfeld NE, Bal W. Copper Transporters? Glutathione Reactivity of Products of Cu-Aβ Digestion by Neprilysin. Inorg Chem 2020; 59:4186-4190. [PMID: 32212682 PMCID: PMC7588031 DOI: 10.1021/acs.inorgchem.0c00427] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Aβ4–42 is the major subspecies of Aβ peptides characterized
by avid Cu(II) binding via the ATCUN/NTS motif. It is thought to be
produced in vivo proteolytically by neprilysin, but in vitro experiments in the presence of Cu(II) ions indicated
preferable formation of C-terminally truncated ATCUN/NTS species including
CuIIAβ4–16, CuIIAβ4–9, and also CuIIAβ12–16, all with nearly femtomolar affinities at neutral pH. Such small
complexes may serve as shuttles for copper clearance from extracellular
brain spaces, on condition they could survive intracellular conditions
upon crossing biological barriers. In order to ascertain such possibility,
we studied the reactions of CuIIAβ4–16, CuIIAβ4–9, CuIIAβ12–16, and CuIIAβ1–16 with reduced glutathione (GSH) under aerobic and anaerobic conditions
using absorption spectroscopy and mass spectrometry. We found CuIIAβ4–16 and CuIIAβ4–9 to be strongly resistant to reduction and concomitant
formation of Cu(I)–GSH complexes, with reaction times ∼10
h, while CuIIAβ12–16 was reduced
within minutes and CuIIAβ1–16 within
seconds of incubation. Upon GSH exhaustion by molecular oxygen, the
CuIIAβ complexes were reformed with no concomitant
oxidative damage to peptides. These finding reinforce the concept
of Aβ4–x peptides as physiological
trafficking partners of brain copper. Aβ4−16, Aβ4−9, and Aβ12−16, oligopeptide products of β-amyloid degradation
by neprilysin, bind CuII ions very tightly and are considered
as possible CuII carriers in the brain. We demonstrated
that CuII(Aβ4−x) complexes, but not CuII(Aβ12−16), are kinetically resistant to reduction by glutathione. No covalent
Aβ peptide modifications were observed during the copper reduction
and reoxidation by ambient oxygen, yielding the original complexes.
These features suggest that CuII(Aβ4−x) complexes might be able to cross the blood−brain
barrier.
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Affiliation(s)
- Ewelina Stefaniak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Dawid Płonka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Paulina Szczerba
- Chair of Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Nina E Wezynfeld
- Chair of Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
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19
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Teng X, Stefaniak E, Girvan P, Kotuniak R, Płonka D, Bal W, Ying L. Hierarchical binding of copperII to N-truncated Aβ4–16 peptide. Metallomics 2020; 12:470-473. [DOI: 10.1039/c9mt00299e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Multiple intermediates were found in Cu(ii) binding to Aβ4–16 before the formation of a tight complex.
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Affiliation(s)
- Xiangyu Teng
- Department of Chemistry
- Imperial College London
- Molecular Sciences Research Hub
- White City Campus
- London W12 0BZ
| | - Ewelina Stefaniak
- Institute of Biochemistry and Biophysics
- Polish Academy of Sciences
- 02-106 Warsaw
- Poland
| | - Paul Girvan
- Department of Chemistry
- Imperial College London
- Molecular Sciences Research Hub
- White City Campus
- London W12 0BZ
| | - Radosław Kotuniak
- Institute of Biochemistry and Biophysics
- Polish Academy of Sciences
- 02-106 Warsaw
- Poland
| | - Dawid Płonka
- Institute of Biochemistry and Biophysics
- Polish Academy of Sciences
- 02-106 Warsaw
- Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics
- Polish Academy of Sciences
- 02-106 Warsaw
- Poland
| | - Liming Ying
- National Heart and Lung Institute
- Imperial College London
- Molecular Sciences Research Hub
- White City Campus
- London W12 0BZ
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20
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Nam E, Nam G, Lim MH. Synaptic Copper, Amyloid-β, and Neurotransmitters in Alzheimer's Disease. Biochemistry 2019; 59:15-17. [PMID: 31603659 DOI: 10.1021/acs.biochem.9b00775] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eunju Nam
- Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
| | - Geewoo Nam
- Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea.,Department of Chemistry , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919 , Republic of Korea
| | - Mi Hee Lim
- Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
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21
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Zn 2+ Interaction with Amyloid-Β: Affinity and Speciation. Molecules 2019; 24:molecules24152796. [PMID: 31370315 PMCID: PMC6695645 DOI: 10.3390/molecules24152796] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 07/26/2019] [Accepted: 07/29/2019] [Indexed: 12/26/2022] Open
Abstract
Conflicting values, obtained by different techniques and often under different experimental conditions have been reported on the affinity of Zn2+ for amyloid-β, that is recognized as the major interaction responsible for Alzheimer’s disease. Here, we compare the approaches employed so far, i.e., the evaluation of Kd and the determination of the stability constants to quantitatively express the affinity of Zn2+ for the amyloid-β peptide, evidencing the pros and cons of the two approaches. We also comment on the different techniques and conditions employed that may lead to divergent data. Through the analysis of the species distribution obtained for two selected examples, we show the implications that the speciation, based on stoichiometric constants rather than on Kd, may have on data interpretation. The paper also demonstrates that the problem is further complicated by the occurrence of multiple equilibria over a relatively narrow pH range.
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22
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Stefaniak E, Bal W. Cu II Binding Properties of N-Truncated Aβ Peptides: In Search of Biological Function. Inorg Chem 2019; 58:13561-13577. [PMID: 31304745 DOI: 10.1021/acs.inorgchem.9b01399] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
As life expectancy increases, the number of people affected by progressive and irreversible dementia, Alzheimer's Disease (AD), is predicted to grow. No drug designs seem to be working in humans, apparently because the origins of AD have not been identified. Invoking amyloid cascade, metal ions, and ROS production hypothesis of AD, herein we share our point of view on Cu(II) binding properties of Aβ4-x, the most prevalent N-truncated Aβ peptide, currently known as the main constituent of amyloid plaques. The capability of Aβ4-x to rapidly take over copper from previously tested Aβ1-x peptides and form highly stable complexes, redox unreactive and resistant to copper exchange reactions, prompted us to propose physiological roles for these peptides. We discuss the new findings on the reactivity of Cu(II)Aβ4-x with coexisting biomolecules in the context of synaptic cleft; we suggest that the role of Aβ4-x peptides is to quench Cu(II) toxicity in the brain and maintain neurotransmission.
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Affiliation(s)
- Ewelina Stefaniak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
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