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Wezynfeld NE, Sudzik D, Tobolska A, Makarova K, Stefaniak E, Frączyk T, Wawrzyniak UE, Bal W. The Angiotensin Metabolite His-Leu Is a Strong Copper Chelator Forming Highly Redox Active Species. Inorg Chem 2024; 63:12268-12280. [PMID: 38877980 PMCID: PMC11220758 DOI: 10.1021/acs.inorgchem.4c01640] [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: 04/22/2024] [Revised: 06/01/2024] [Accepted: 06/03/2024] [Indexed: 07/02/2024]
Abstract
His-Leu is a hydrolytic byproduct of angiotensin metabolism, whose concentration in the bloodstream could be at least micromolar. This encouraged us to investigate its Cu(II) binding properties and the concomitant redox reactivity. The Cu(II) binding constants were derived from isothermal titration calorimetry and potentiometry, while identities and structures of complexes were obtained from ultraviolet-visible, circular dichroism, and room-temperature electronic paramagnetic resonance spectroscopies. Four types of Cu(II)/His-Leu complexes were detected. The histamine-like complexes prevail at low pH. At neutral and mildly alkaline pH and low Cu(II):His-Leu ratios, they are superseded by diglycine-like complexes involving the deprotonated peptide nitrogen. At His-Leu:Cu(II) ratios of ≥2, bis-complexes are formed instead. Above pH 10.5, a diglycine-like complex containing the equatorially coordinated hydroxyl group predominates at all ratios tested. Cu(II)/His-Leu complexes are also strongly redox active, as demonstrated by voltammetric studies and the ascorbate oxidation assay. Finally, numeric competition simulations with human serum albumin, glycyl-histydyl-lysine, and histidine revealed that His-Leu might be a part of the low-molecular weight Cu(II) pool in blood if its abundance is >10 μM. These results yield further questions, such as the biological relevance of ternary complexes containing His-Leu.
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Affiliation(s)
- Nina E. Wezynfeld
- Chair of
Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Dobromiła Sudzik
- Institute
of Biochemistry and Biophysics, Polish Academy
of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Aleksandra Tobolska
- Chair of
Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Katerina Makarova
- Institute
of Biochemistry and Biophysics, Polish Academy
of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
- Department
of Organic and Physical Chemistry, Faculty
of Pharmacy, Medical University of Warsaw, Żwirki i Wigury 61, 02-091 Warsaw, Poland
| | - Ewelina Stefaniak
- Institute
of Biochemistry and Biophysics, Polish Academy
of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
- National
Heart and Lung Institute, Imperial College
London, Molecular Sciences
Research Hub, London W12
0BZ, United Kingdom
| | - Tomasz Frączyk
- 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
| | - Wojciech Bal
- Institute
of Biochemistry and Biophysics, Polish Academy
of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
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2
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Ekanayake RSK, Streltsov VA, Best SP, Chantler CT. Nanostructure and dynamics of N-truncated copper amyloid-β peptides from advanced X-ray absorption fine structure. IUCRJ 2024; 11:325-346. [PMID: 38602752 PMCID: PMC11067746 DOI: 10.1107/s2052252524001830] [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: 09/29/2023] [Accepted: 02/26/2024] [Indexed: 04/12/2024]
Abstract
An X-ray absorption spectroscopy (XAS) electrochemical cell was used to collect high-quality XAS measurements of N-truncated Cu:amyloid-β (Cu:Aβ) samples under near-physiological conditions. N-truncated Cu:Aβ peptide complexes contribute to oxidative stress and neurotoxicity in Alzheimer's patients' brains. However, the redox properties of copper in different Aβ peptide sequences are inconsistent. Therefore, the geometry of binding sites for the copper binding in Aβ4-8/12/16 was determined using novel advanced extended X-ray absorption fine structure (EXAFS) analysis. This enables these peptides to perform redox cycles in a manner that might produce toxicity in human brains. Fluorescence XAS measurements were corrected for systematic errors including defective-pixel data, monochromator glitches and dispersion of pixel spectra. Experimental uncertainties at each data point were measured explicitly from the point-wise variance of corrected pixel measurements. The copper-binding environments of Aβ4-8/12/16 were precisely determined by fitting XAS measurements with propagated experimental uncertainties, advanced analysis and hypothesis testing, providing a mechanism to pursue many similarly complex questions in bioscience. The low-temperature XAS measurements here determine that CuII is bound to the first amino acids in the high-affinity amino-terminal copper and nickel (ATCUN) binding motif with an oxygen in a tetragonal pyramid geometry in the Aβ4-8/12/16 peptides. Room-temperature XAS electrochemical-cell measurements observe metal reduction in the Aβ4-16 peptide. Robust investigations of XAS provide structural details of CuII binding with a very different bis-His motif and a water oxygen in a quasi-tetrahedral geometry. Oxidized XAS measurements of Aβ4-12/16 imply that both CuII and CuIII are accommodated in an ATCUN-like binding site. Hypotheses for these CuI, CuII and CuIII geometries were proven and disproven using the novel data and statistical analysis including F tests. Structural parameters were determined with an accuracy some tenfold better than literature claims of past work. A new protocol was also developed using EXAFS data analysis for monitoring radiation damage. This gives a template for advanced analysis of complex biosystems.
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Affiliation(s)
| | - Victor A. Streltsov
- School of Physics, University of Melbourne, Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Australia
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3
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Strausbaugh Hjelmstad A, Pushie MJ, Ruth K, Escobedo M, Kuter K, Haas KL. Investigating Cu(I) binding to model peptides of N-terminal Aβ isoforms. J Inorg Biochem 2024; 253:112480. [PMID: 38309203 DOI: 10.1016/j.jinorgbio.2024.112480] [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: 10/03/2023] [Revised: 12/10/2023] [Accepted: 01/02/2024] [Indexed: 02/05/2024]
Abstract
Amyloid beta (Aβ) peptides and copper (Cu) ions are each involved in critical biological processes including antimicrobial activity, regulation of synaptic function, angiogenesis, and others. Aβ binds to Cu and may play a role in Cu trafficking. Aβ peptides exist in isoforms that vary at their C-and N-termini; variation at the N-terminal sequence affects Cu binding affinity, structure, and redox activity by providing different sets of coordinating groups to the metal ion. Several N-terminal isoforms have been detected in human brain tissues including Aβ1-40/42, Aβ3-42, pEAβ3-42, Aβ4-42, Aβ11-40 and pEAβ11-40 (where pE denotes an N-terminal pyroglutamic acid). Several previous works have individually investigated the affinity and structure of Cu(I) bound to some of these isoforms' metal binding domains. However, the disparately reported values are apparent constants collected under different sets of conditions, and thus an integrated comparison cannot be made. The work presented here provides the Cu(I) coordination structure and binding affinities of these six biologically relevant Aβ isoforms determined in parallel using model peptides of the Aβ metal binding domains (Aβ1-16, Aβ3-16, pEAβ3-16, Aβ4-16, Aβ11-16 and pEAβ11-16). The binding affinities of Cu(I)-Aβ complexes were measured using solution competition with ferrozine (Fz) and bicinchoninic acid (BCA), two colorimetric Cu(I) indicators in common use. The Cu(I) coordination structures were characterized by X-ray absorption spectroscopy. The data presented here facilitate comparison of the isoforms' Cu-binding interactions and contribute to our understanding of the role of Aβ peptides as copper chelators in healthy and diseased brains.
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Affiliation(s)
| | - M Jake Pushie
- Department of Surgery, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Kaylee Ruth
- Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Maria Escobedo
- Department of Mathematics and Computer Science, Saint Mary's College, Notre Dame, Indiana 46556, USA
| | - Kristin Kuter
- Department of Mathematics and Computer Science, Saint Mary's College, Notre Dame, Indiana 46556, USA
| | - Kathryn L Haas
- Department of Chemistry, Duke University, Durham, NC 27708, USA.
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4
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De Santis E, Alleva S, Minicozzi V, Morante S, Stellato F. Probing the Dynamic Landscape: From Static to Time-Resolved X-Ray Absorption Spectroscopy to Investigate Copper Redox Chemistry in Neurodegenerative Disorders. Chempluschem 2024:e202300712. [PMID: 38526934 DOI: 10.1002/cplu.202300712] [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] [Received: 12/01/2023] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 03/27/2024]
Abstract
Copper (Cu), with its ability to exist in various oxidation states, notably Cu(I) and Cu(II), plays a crucial role in diverse biological redox reactions. This includes its involvement in pathways associated with oxidative stress in neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and Transmissible Spongiform Encephalopathies. This paper offers an overview of X-ray Absorption Spectroscopy (XAS) studies designed to elucidate the interactions between Cu ions and proteins or peptides associated with these neurodegenerative diseases. The emphasis lies on XAS specificity, revealing the local coordination environment, and on its sensitivity to Cu oxidation states. Furthermore, the paper focuses on XAS applications targeting the characterization of intermediate reaction states and explores the opportunities arising from recent advancements in time-resolved XAS at ultrabright synchrotron and Free Electron Laser radiation sources.
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Affiliation(s)
- Emiliano De Santis
- Department of Chemistry-BMC, Uppsala University, Box 576, SE-751 23, Uppsala, Sweden
| | - Stefania Alleva
- Department of Physics, University of Rome, Tor Vergata, Rome, 00133, Italy
- INFN, Rome, Tor Vergata, Rome, 00133, Italy
| | - Velia Minicozzi
- Department of Physics, University of Rome, Tor Vergata, Rome, 00133, Italy
- INFN, Rome, Tor Vergata, Rome, 00133, Italy
| | - Silvia Morante
- Department of Physics, University of Rome, Tor Vergata, Rome, 00133, Italy
- INFN, Rome, Tor Vergata, Rome, 00133, Italy
| | - Francesco Stellato
- Department of Physics, University of Rome, Tor Vergata, Rome, 00133, Italy
- INFN, Rome, Tor Vergata, Rome, 00133, Italy
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5
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Grcic L, Leech G, Kwan K, Storr T. Targeting misfolding and aggregation of the amyloid-β peptide and mutant p53 protein using multifunctional molecules. Chem Commun (Camb) 2024; 60:1372-1388. [PMID: 38204416 DOI: 10.1039/d3cc05834d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Biomolecule misfolding and aggregation play a major role in human disease, spanning from neurodegeneration to cancer. Inhibition of these processes is of considerable interest, and due to the multifactorial nature of these diseases, the development of drugs that act on multiple pathways simultaneously is a promising approach. This Feature Article focuses on the development of multifunctional molecules designed to inhibit the misfolding and aggregation of the amyloid-β (Aβ) peptide in Alzheimer's disease (AD), and the mutant p53 protein in cancer. While for the former, the goal is to accelerate the removal of the Aβ peptide and associated aggregates, for the latter, the goal is reactivation via stabilization of the active folded form of mutant p53 protein and/or aggregation inhibition. Due to the similar aggregation pathway of the Aβ peptide and mutant p53 protein, a common therapeutic approach may be applicable.
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Affiliation(s)
- Lauryn Grcic
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
| | - Grace Leech
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
| | - Kalvin Kwan
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
| | - Tim Storr
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
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6
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Falcone E, Hureau C. Redox processes in Cu-binding proteins: the "in-between" states in intrinsically disordered peptides. Chem Soc Rev 2023; 52:6595-6600. [PMID: 37701947 PMCID: PMC10544051 DOI: 10.1039/d3cs00443k] [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: 06/07/2023] [Indexed: 09/14/2023]
Abstract
We report on a concept that some of us first described a decade ago for pure electron transfer [V. Balland, C. Hureau and J.-M. Savéant, Proc. Natl. Acad. Sci. U. S. A., 2010, 107, 17113]. In the present viewpoint, based on more recent results, we refine and extend this "in-between state" concept to explain the formation of reactive oxygen species by copper ions bound to the amyloid-β (Aβ) peptide involved in Alzheimer's disease. In such intrinsically disordered peptides, the Cu coordination is versatile due to the lack of stable folding and the presence of multiple possible binding anchors. Hence, the Cu(I) and Cu(II) ions do impose their favoured sites, with Cu(I) bound in a linear fashion between two His residues and Cu(II) in a square-based pyramid bound to Asp1 amine and carbonyl groups and two His residues in the equatorial plane. Hence a direct electron transfer is prevented and alternatively an in-between state (IBS) mechanism applies, whose description and analysis with respect to other electron transfer processes is the topic of the present viewpoint.
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Affiliation(s)
- Enrico Falcone
- Institut de Chimie (UMR 7177), Université de Strasbourg, CNRS, Strasbourg, France
- School of Chemistry, University of Nottingham, Nottingham, UK
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7
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Chen LL, Fan YG, Zhao LX, Zhang Q, Wang ZY. The metal ion hypothesis of Alzheimer's disease and the anti-neuroinflammatory effect of metal chelators. Bioorg Chem 2023; 131:106301. [PMID: 36455485 DOI: 10.1016/j.bioorg.2022.106301] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/13/2022] [Accepted: 11/22/2022] [Indexed: 11/26/2022]
Abstract
Alzheimer's disease (AD), characterized by the β-amyloid protein (Aβ) deposition and tau hyperphosphorylation, is the most common dementia with uncertain etiology. The clinical trials of Aβ monoclonal antibody drugs have almost failed, giving rise to great attention on the other etiologic hypothesis regarding AD such as metal ions dysmetabolism and chronic neuroinflammation. Mounting evidence revealed that the metal ions (iron, copper, and zinc) were dysregulated in the susceptible brain regions of AD patients, which was highly associated with Aβ deposition, tau hyperphosphorylation, neuronal loss, as well as neuroinflammation. Further studies uncovered that iron, copper and zinc could not only enhance the production of Aβ but also directly bind to Aβ and tau to promote their aggregations. In addition, the accumulation of iron and copper could respectively promote ferroptosis and cuproptosis. Therefore, the metal ion chelators were recognized as promising agents for treating AD. This review comprehensively summarized the effects of metal ions on the Aβ dynamics and tau phosphorylation in the progression of AD. Furthermore, taking chronic neuroinflammation contributes to the progression of AD, we also provided a summary of the mechanisms concerning metal ions on neuroinflammation and highlighted the metal ion chelators may be potential agents to alleviate neuroinflammation under the condition of AD. Nevertheless, more investigations regarding metal ions on neuroinflammation should be taken into practice, and the effects of metal ion chelators on neuroinflammation should gain more attention. Running title: Metal chelators against neuroinflammation.
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Affiliation(s)
- Li-Lin Chen
- Key Laboratory of Medical Cell Biology of Ministry of Education, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, Health Sciences Institute of China Medical University, Shenyang 110122, China
| | - Yong-Gang Fan
- Key Laboratory of Medical Cell Biology of Ministry of Education, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, Health Sciences Institute of China Medical University, Shenyang 110122, China
| | - Ling-Xiao Zhao
- Key Laboratory of Medical Cell Biology of Ministry of Education, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, Health Sciences Institute of China Medical University, Shenyang 110122, China
| | - Qi Zhang
- Key Laboratory of Medical Cell Biology of Ministry of Education, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, Health Sciences Institute of China Medical University, Shenyang 110122, China
| | - Zhan-You Wang
- Key Laboratory of Medical Cell Biology of Ministry of Education, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, Health Sciences Institute of China Medical University, Shenyang 110122, China.
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8
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Tobolska A, Głowacz K, Ciosek-Skibińska P, Bal W, Wróblewski W, Wezynfeld NE. Dual mode of voltammetric studies on Cu(II) complexes of His2 peptides: phosphate and peptide sequence recognition. Dalton Trans 2022; 51:18143-18151. [PMID: 36385190 DOI: 10.1039/d2dt03078k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Copper(II) complexes of peptides with a histidine residue at the second position (His2 peptides) provide a unique profile of electrochemical behavior, offering signals of both Cu(II) reduction and Cu(II) oxidation. Furthermore, their structures with vacant positions in the equatorial coordination plane could facilitate interactions with other biomolecules. In this work, we designed a library of His2 peptides based on the sequence of Aβ5-9 (RHDSG), an amyloid beta peptide derivative. The changes in the Aβ5-9 sequence highly affect the Cu(II) oxidation signals, altered further by anionic species. As a result, Cu(II) complexes of Arg1 peptides without Asp residues were chosen as the most promising peptide-based molecular receptors for phosphates. The voltammetric data on Cu(II) oxidation for binary Cu(II)-His2 peptide complexes and ternary Cu(II)-His2 peptide/phosphate systems were also tested for His2 peptide recognition. We achieved a highly promising identification of subtle modifications in the peptide sequence. Thus, we introduce voltammetric measurement as a potential novel tool for peptide sequence recognition.
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Affiliation(s)
- Aleksandra Tobolska
- Chair of Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland. .,Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Klaudia Głowacz
- Chair of Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Patrycja Ciosek-Skibińska
- 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
| | - Wojciech Wróblewski
- 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.
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9
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Sequence-Activity Relationship of ATCUN Peptides in the Context of Alzheimer's Disease. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27227903. [PMID: 36432004 PMCID: PMC9698028 DOI: 10.3390/molecules27227903] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 11/17/2022]
Abstract
Amino-terminal CuII and NiII (ATCUN) binding sequences are widespread in the biological world. Here, we report on the study of eight ATCUN peptides aimed at targeting copper ions and stopping the associated formation of reactive oxygen species (ROS). This study was actually more focused on Cu(Aβ)-induced ROS production in which the Aβ peptide is the "villain" linked to Alzheimer's disease. The full characterization of CuII binding to the ATCUN peptides, the CuII extraction from CuII(Aβ), and the ability of the peptides to prevent and/or stop ROS formation are described in the relevant biological conditions. We highlighted in this research that all the ATCUN motifs studied formed the same thermodynamic complex but that the addition of a second histidine in position 1 or 2 allowed for an improvement in the CuII uptake kinetics. This kinetic rate was directly related to the ability of the peptide to stop the CuII(Aβ)-induced production of ROS, with the most efficient motifs being HWHG and HGHW.
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10
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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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11
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Picone P, Sanfilippo T, Vasto S, Baldassano S, Guggino R, Nuzzo D, Bulone D, San Biagio PL, Muscolino E, Monastero R, Dispenza C, Giacomazza D. From Small Peptides to Large Proteins against Alzheimer’sDisease. Biomolecules 2022; 12:biom12101344. [PMID: 36291553 PMCID: PMC9599460 DOI: 10.3390/biom12101344] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/15/2022] [Accepted: 09/17/2022] [Indexed: 11/16/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common neurodegenerative disorder in the elderly. The two cardinal neuropathological hallmarks of AD are the senile plaques, which are extracellular deposits mainly constituted by beta-amyloids, and neurofibrillary tangles formed by abnormally phosphorylated Tau (p-Tau) located in the cytoplasm of neurons. Although the research has made relevant progress in the management of the disease, the treatment is still lacking. Only symptomatic medications exist for the disease, and, in the meantime, laboratories worldwide are investigating disease-modifying treatments for AD. In the present review, results centered on the use of peptides of different sizes involved in AD are presented.
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Affiliation(s)
- Pasquale Picone
- Istituto per la Ricerca e l’Innovazione Biomedica, Consiglio Nazionale delle Ricerche, Via U. La Malfa 153, 90146 Palermo, Italy
- Dipartmento of Scienze Biologiche, Chimiche, Farmaceutiche e Tecnologiche (STEBICEF), University of Palermo, 90128 Palermo, Italy
| | - Tiziana Sanfilippo
- Ambulatorio di Nutrizione Clinica ASP Palermo, Via G. Cusmano 24, 90141 Palermo, Italy
- Anestesia e Rianimazione, Presidio Ospedaliero “S. Cimino”, 90141 Termini Imerese, Italy
| | - Sonya Vasto
- Dipartmento of Scienze Biologiche, Chimiche, Farmaceutiche e Tecnologiche (STEBICEF), University of Palermo, 90128 Palermo, Italy
- Istituti Euro-Mediterranei di Scienza e Tecnologia (IEMEST), Via M. Miraglia 20, 90139 Palermo, Italy
| | - Sara Baldassano
- Dipartmento of Scienze Biologiche, Chimiche, Farmaceutiche e Tecnologiche (STEBICEF), University of Palermo, 90128 Palermo, Italy
| | - Rossella Guggino
- Ambulatorio di Nutrizione Clinica ASP Palermo, Via G. Cusmano 24, 90141 Palermo, Italy
- Anestesia e Rianimazione, Presidio Ospedaliero “S. Cimino”, 90141 Termini Imerese, Italy
| | - Domenico Nuzzo
- Istituto per la Ricerca e l’Innovazione Biomedica, Consiglio Nazionale delle Ricerche, Via U. La Malfa 153, 90146 Palermo, Italy
- Dipartmento of Scienze Biologiche, Chimiche, Farmaceutiche e Tecnologiche (STEBICEF), University of Palermo, 90128 Palermo, Italy
- Correspondence: (D.N.); (D.G.)
| | - Donatella Bulone
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via U. La Malfa 153, 90146 Palermo, Italy
| | - Pier Luigi San Biagio
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via U. La Malfa 153, 90146 Palermo, Italy
| | - Emanuela Muscolino
- Dipartimento di Ingegneria, Università degli Studi di Palermo, Viale delle Scienze, Bldg 6, 90128 Palermo, Italy
| | - Roberto Monastero
- Dipartimento di Biomedicina, Neuroscienze e Diagnostica Avanzata, Università degli Studi di Palermo, Via del Vespro 129, 90127 Palermo, Italy
| | - Clelia Dispenza
- Dipartimento di Ingegneria, Università degli Studi di Palermo, Viale delle Scienze, Bldg 6, 90128 Palermo, Italy
| | - Daniela Giacomazza
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via U. La Malfa 153, 90146 Palermo, Italy
- Correspondence: (D.N.); (D.G.)
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12
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Why the Ala-His-His Peptide Is an Appropriate Scaffold to Remove and Redox Silence Copper Ions from the Alzheimer’s-Related Aβ Peptide. Biomolecules 2022; 12:biom12101327. [PMID: 36291536 PMCID: PMC9599918 DOI: 10.3390/biom12101327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/09/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
The progressive, neurodegenerative Alzheimer’s disease (AD) is the most widespread dementia. Due to the ageing of the population and the current lack of molecules able to prevent or stop the disease, AD will be even more impactful for society in the future. AD is a multifactorial disease, and, among other factors, metal ions have been regarded as potential therapeutic targets. This is the case for the redox-competent Cu ions involved in the production of reactive oxygen species (ROS) when bound to the Alzheimer-related Aβ peptide, a process that contributes to the overall oxidative stress and inflammation observed in AD. Here, we made use of peptide ligands to stop the Cu(Aβ)-induced ROS production and we showed why the AHH sequence is fully appropriate, while the two parents, AH and AAH, are not. The AHH peptide keeps its beneficial ability against Cu(Aβ)-induced ROS, even in the presence of ZnII-competing ions and other biologically relevant ions. The detailed kinetic mechanism by which AHH could exert its action against Cu(Aβ)-induced ROS is also proposed.
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13
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Wiloch MZ, Jönsson-Niedziółka M. Very small changes in the peptide sequence alter the redox properties of Aβ(11-16)-Cu(II) and pAβ(11–16)-Cu(II) β-amyloid complexes. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Wiloch MZ, Baran N, Jonsson-Niedziolka M. The Influence of Coordination Mode on the Redox Properties of Copper Complexes with Aβ(3‐16) and its Pyroglutamate Counterpart pAβ(3‐16). ChemElectroChem 2022. [DOI: 10.1002/celc.202200623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Magdalena Z. Wiloch
- Institute of Physical Chemistry PAS: Polska Akademia Nauk Instytut Chemii Fizycznej Department of Electrode Processes POLAND
| | - Natalia Baran
- Institute of Physical Chemistry PAS: Polska Akademia Nauk Instytut Chemii Fizycznej Department of Electrode Processes POLAND
| | - Martin Jonsson-Niedziolka
- Institute of Physical Chemistry, PAS Department of electrode processes Kasprzaka 44/52 01-224 Warsaw POLAND
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15
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Okafor M, Gonzalez P, Ronot P, El Masoudi I, Boos A, Ory S, Chasserot-Golaz S, Gasman S, Raibaut L, Hureau C, Vitale N, Faller P. Development of Cu( ii)-specific peptide shuttles capable of preventing Cu–amyloid beta toxicity and importing bioavailable Cu into cells. Chem Sci 2022; 13:11829-11840. [PMID: 36320914 PMCID: PMC9580518 DOI: 10.1039/d2sc02593k] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/20/2022] [Indexed: 11/21/2022] Open
Abstract
Copper (Cu) in its ionic forms is an essential element for mammals and its homeostasis is tightly controlled. Accordingly, Cu-dyshomeostasis can be lethal as is the case in the well-established genetic Wilson's and Menkes diseases. In Alzheimer's disease (AD), Cu-accumulation occurs in amyloid plaques, where it is bound to the amyloid-beta peptide (Aβ). In vitro, Cu–Aβ is competent to catalyze the production of reactive oxygen species (ROS) in the presence of ascorbate under aerobic conditions, and hence Cu–Aβ is believed to contribute to the oxidative stress in AD. Several molecules that can recover extracellular Cu from Aβ and transport it back into cells with beneficial effects in cell culture and transgenic AD models were identified. However, all the Cu-shuttles currently available are not satisfactory due to various potential limitations including ion selectivity and toxicity. Hence, we designed a novel peptide-based Cu shuttle with the following properties: (i) it contains a Cu(ii)-binding motif that is very selective to Cu(ii) over all other essential metal ions; (ii) it is tagged with a fluorophore sensitive to Cu(ii)-binding and release; (iii) it is made of a peptide platform, which is very versatile to add new functions. The work presented here reports on the characterization of AKH-αR5W4NBD, which is able to transport Cu ions selectively into PC12 cells and the imported Cu appeared bioavailable, likely via reductive release induced by glutathione. Moreover, AKH-αR5W4NBD was able to withdraw Cu from the Aβ1–16 peptide and consequently inhibited the Cu-Aβ based reactive oxygen species production and related cell toxicity. Hence, AKH-αR5W4NBD could be a valuable new tool for Cu-transport into cells and suitable for mechanistic studies in cell culture, with potential applications in restoring Cu-homeostasis in Cu-related diseases such as AD. The synthetic peptide AKH-αR5W4NBD was designed as a shuttle to counteract copper imbalance in Alzheimer’s disease. In vitro, this shuttle is able to abstract Cu(ii) selectively from amyloid-β and transport it into cells in a bioavailable form.![]()
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Affiliation(s)
- Michael Okafor
- Laboratory of Biometals and Biological Chemistry, Institut de Chimie (UMR 7177), Université de Strasbourg-CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Paulina Gonzalez
- Laboratory of Biometals and Biological Chemistry, Institut de Chimie (UMR 7177), Université de Strasbourg-CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Pascale Ronot
- Université de Strasbourg, CNRS, IPHC, UMR 7178, F-67000 Strasbourg, France
| | - Islah El Masoudi
- Université de Strasbourg, CNRS, IPHC, UMR 7178, F-67000 Strasbourg, France
| | - Anne Boos
- Université de Strasbourg, CNRS, IPHC, UMR 7178, F-67000 Strasbourg, France
| | - Stéphane Ory
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Sylvette Chasserot-Golaz
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Stéphane Gasman
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Laurent Raibaut
- Laboratory of Biometals and Biological Chemistry, Institut de Chimie (UMR 7177), Université de Strasbourg-CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | | | - Nicolas Vitale
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Peter Faller
- Laboratory of Biometals and Biological Chemistry, Institut de Chimie (UMR 7177), Université de Strasbourg-CNRS, 4 Rue Blaise Pascal, 67000 Strasbourg, France
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16
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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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17
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Beuning CN, Zocchi LJ, Malikidogo KP, Esmieu C, Dorlet P, Crans DC, Hureau C. Measurement of Interpeptidic Cu II Exchange Rate Constants of Cu II-Amyloid-β Complexes to Small Peptide Motifs by Tryptophan Fluorescence Quenching. Inorg Chem 2021; 60:7650-7659. [PMID: 33983723 DOI: 10.1021/acs.inorgchem.0c03555] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The interpeptidic CuII exchange rate constants were measured for two Cu amyloid-β complexes, Cu(Aβ1-16) and Cu(Aβ1-28), to fluorescent peptides GHW and DAHW using a quantitative tryptophan fluorescence quenching methodology. The second-order rate constants were determined at three pH values (6.8, 7.4, and 8.7) important to the two Cu(Aβ) coordination complexes, components Cu(Aβ)I and Cu(Aβ)II. The interpeptidic CuII exchange rate constant is approximately 104 M-1 s-1 but varies in magnitude depending on many variables. These include pH, length of the Aβ peptide, location of the anchoring histidine ligand in the fluorescent peptide, number of amide deprotonations required in the tryptophan peptide to coordinate CuII, and interconversion between Cu(Aβ)I and Cu(Aβ)II. We also present EPR data probing the CuII exchange between peptides and the formation of ternary species between Cu(Aβ) and GHW. As the nonfluorescent GHK and DAHK peptides are important motifs found in the blood and serum, their ability to sequester CuII ions from Cu(Aβ) complexes may be relevant for the metal homeostasis and its implication in Alzheimer's disease. Thus, their kinetic CuII interpeptidic exchange rate constants are important chemical rate constants that can help elucidate the complex CuII trafficking puzzle in the synaptic cleft.
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Affiliation(s)
- Cheryle N Beuning
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Luca J Zocchi
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | | | | | - Pierre Dorlet
- CNRS, Aix-Marseille Université, Laboratoire de Bioénergétique et Ingénierie des Protéines, IMM, 13400 Marseille, France
| | - Debbie C Crans
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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18
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Oxidase Reactivity of Cu II Bound to N-Truncated Aβ Peptides Promoted by Dopamine. Int J Mol Sci 2021; 22:ijms22105190. [PMID: 34068879 PMCID: PMC8155989 DOI: 10.3390/ijms22105190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/10/2021] [Accepted: 05/12/2021] [Indexed: 12/18/2022] Open
Abstract
The redox chemistry of copper(II) is strongly modulated by the coordination to amyloid-β peptides and by the stability of the resulting complexes. Amino-terminal copper and nickel binding motifs (ATCUN) identified in truncated Aβ sequences starting with Phe4 show very high affinity for copper(II) ions. Herein, we study the oxidase activity of [Cu–Aβ4−x] and [Cu–Aβ1−x] complexes toward dopamine and other catechols. The results show that the CuII–ATCUN site is not redox-inert; the reduction of the metal is induced by coordination of catechol to the metal and occurs through an inner sphere reaction. The generation of a ternary [CuII–Aβ–catechol] species determines the efficiency of the oxidation, although the reaction rate is ruled by reoxidation of the CuI complex. In addition to the N-terminal coordination site, the two vicinal histidines, His13 and His14, provide a second Cu-binding motif. Catechol oxidation studies together with structural insight from the mixed dinuclear complexes Ni/Cu–Aβ4−x reveal that the His-tandem is able to bind CuII ions independently of the ATCUN site, but the N-terminal metal complexation reduces the conformational mobility of the peptide chain, preventing the binding and oxidative reactivity toward catechol of CuII bound to the secondary site.
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19
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Bataglioli JC, Gomes LMF, Maunoir C, Smith JR, Cole HD, McCain J, Sainuddin T, Cameron CG, McFarland SA, Storr T. Modification of amyloid-beta peptide aggregation via photoactivation of strained Ru(ii) polypyridyl complexes. Chem Sci 2021; 12:7510-7520. [PMID: 34163842 PMCID: PMC8171320 DOI: 10.1039/d1sc00004g] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 04/19/2021] [Indexed: 01/01/2023] Open
Abstract
Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by progressive and irreversible damage to the brain. One of the hallmarks of the disease is the presence of both soluble and insoluble aggregates of the amyloid beta (Aβ) peptide in the brain, and these aggregates are considered central to disease progression. Thus, the development of small molecules capable of modulating Aβ peptide aggregation may provide critical insight into the pathophysiology of AD. In this work we investigate how photoactivation of three distorted Ru(ii) polypyridyl complexes (Ru1-3) alters the aggregation profile of the Aβ peptide. Photoactivation of Ru1-3 results in the loss of a 6,6'-dimethyl-2,2'-bipyridyl (6,6'-dmb) ligand, affording cis-exchangeable coordination sites for binding to the Aβ peptide. Both Ru1 and Ru2 contain an extended planar imidazo[4,5-f][1,10]phenanthroline ligand, as compared to a 2,2'-bipyridine ligand for Ru3, and we show that the presence of the phenanthroline ligand promotes covalent binding to Aβ peptide His residues, and in addition, leads to a pronounced effect on peptide aggregation immediately after photoactivation. Interestingly, all three complexes resulted in a similar aggregate size distribution at 24 h, forming insoluble amorphous aggregates as compared to significant fibril formation for peptide alone. Photoactivation of Ru1-3 in the presence of pre-formed Aβ1-42 fibrils results in a change to amorphous aggregate morphology, with Ru1 and Ru2 forming large amorphous aggregates immediately after activation. Our results show that photoactivation of Ru1-3 in the presence of either monomeric or fibrillar Aβ1-42 results in the formation of large amorphous aggregates as a common endpoint, with Ru complexes incorporating the extended phenanthroline ligand accelerating this process and thereby limiting the formation of oligomeric species in the initial stages of the aggregation process that are reported to show considerable toxicity.
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Affiliation(s)
| | - Luiza M F Gomes
- Department of Chemistry, Simon Fraser University BC Canada V5A-1S6
| | - Camille Maunoir
- Department of Chemistry, Simon Fraser University BC Canada V5A-1S6
| | - Jason R Smith
- Department of Chemistry, Simon Fraser University BC Canada V5A-1S6
| | - Houston D Cole
- Department of Chemistry and Biochemistry, University of Texas Arlington Texas USA 76019
| | - Julia McCain
- Department of Chemistry, Acadia University Wolfville Nova Scotia Canada B4P 2R6
| | - Tariq Sainuddin
- Department of Chemistry, Acadia University Wolfville Nova Scotia Canada B4P 2R6
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, University of Texas Arlington Texas USA 76019
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, University of Texas Arlington Texas USA 76019
| | - Tim Storr
- Department of Chemistry, Simon Fraser University BC Canada V5A-1S6
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20
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Esmieu C, Balderrama-Martínez-Sotomayor R, Conte-Daban A, Iranzo O, Hureau C. Unexpected Trends in Copper Removal from Aβ Peptide: When Less Ligand Is Better and Zn Helps. Inorg Chem 2021; 60:1248-1256. [PMID: 33400522 DOI: 10.1021/acs.inorgchem.0c03407] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cu, Zn, and amyloid-β (Aβ) peptides play an important role in the etiology of Alzheimer's disease (AD). Their interaction indeed modifies the self-assembly propensity of the peptide that is at the origin of the deposition of insoluble peptide aggregates in the amyloid plaque, a hallmark found in AD brains. Another even more important fallout of the Cu binding to Aβ peptide is the formation of reactive oxygen species (ROS) that contributes to the overall oxidative stress detected in the disease and is due to the redox ability of the Cu ions. Many therapeutic approaches are currently developed to aid fighting against AD, one of them targeting the redox-active Cu ions. Along this research line, we report in the present article the use of a phenanthroline-based peptide-like ligand (L), which is able to withdraw Cu from Aβ and redox-silence it in a very stable 4N Cu(II) binding site even in the presence of Zn(II). In addition and in contrast to what is usually observed, the presence of excess of L lessens the searched effect of ROS production prevention, but it is counterbalanced by the co-presence of Zn(II). To explain such unprecedented trends, we proposed a mechanism that involves the redox reaction between Cu(II)L and Cu(I)L2. We thus illustrated (i) how speciation and redox chemistry can weaken the effect of a ligand that would have appeared perfectly suitable if only tested in a 1:1 ratio and on CuAβ and (ii) how Zn overcomes the undesired lessening of ROS arrest due to excess of ligand. In brief, we have shown how working in biologically relevant conditions is important for the understanding of all of the reactions at play and this must be taken into consideration for the further rational design of ligands aiming to become drug candidates.
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Affiliation(s)
- Charlène Esmieu
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, 31077 Toulouse, Cedex 4, France
| | | | - Amandine Conte-Daban
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, 31077 Toulouse, Cedex 4, France
| | - Olga Iranzo
- Aix Marseille University, CNRS, Centrale Marseille, iSm2, Campus Scientifique de St Jérôme, 13397 Marseille, France
| | - Christelle Hureau
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, 31077 Toulouse, Cedex 4, France
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21
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Mital M, Szutkowski K, Bossak-Ahmad K, Skrobecki P, Drew SC, Poznański J, Zhukov I, Frączyk T, Bal W. The Palladium(II) Complex of A β4-16 as Suitable Model for Structural Studies of Biorelevant Copper(II) Complexes of N-Truncated Beta-Amyloids. Int J Mol Sci 2020; 21:E9200. [PMID: 33276669 PMCID: PMC7731285 DOI: 10.3390/ijms21239200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/26/2020] [Accepted: 11/30/2020] [Indexed: 11/16/2022] Open
Abstract
The Aβ4-42 peptide is a major beta-amyloid species in the human brain, forming toxic aggregates related to Alzheimer's Disease. It also strongly chelates Cu(II) at the N-terminal Phe-Arg-His ATCUN motif, as demonstrated in Aβ4-16 and Aβ4-9 model peptides. The resulting complex resists ROS generation and exchange processes and may help protect synapses from copper-related oxidative damage. Structural characterization of Cu(II)Aβ4-x complexes by NMR would help elucidate their biological function, but is precluded by Cu(II) paramagneticism. Instead we used an isostructural diamagnetic Pd(II)-Aβ4-16 complex as a model. To avoid a kinetic trapping of Pd(II) in an inappropriate transient structure, we designed an appropriate pH-dependent synthetic procedure for ATCUN Pd(II)Aβ4-16, controlled by CD, fluorescence and ESI-MS. Its assignments and structure at pH 6.5 were obtained by TOCSY, NOESY, ROESY, 1H-13C HSQC and 1H-15N HSQC NMR experiments, for natural abundance 13C and 15N isotopes, aided by corresponding experiments for Pd(II)-Phe-Arg-His. The square-planar Pd(II)-ATCUN coordination was confirmed, with the rest of the peptide mostly unstructured. The diffusion rates of Aβ4-16, Pd(II)-Aβ4-16 and their mixture determined using PGSE-NMR experiment suggested that the Pd(II) complex forms a supramolecular assembly with the apopeptide. These results confirm that Pd(II) substitution enables NMR studies of structural aspects of Cu(II)-Aβ complexes.
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Affiliation(s)
- Mariusz Mital
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Kosma Szutkowski
- NanoBioMedical Centre, Adam Mickiewicz University, 61-614 Poznań, Poland;
| | - Karolina Bossak-Ahmad
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Piotr Skrobecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Simon C. Drew
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Jarosław Poznański
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Igor Zhukov
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Tomasz Frączyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
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