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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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2
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Mahl CRA, Bataglioli RA, Calais GB, Taketa TB, Beppu MM. Role of Alginate Composition on Copper Ion Uptake in the Presence of Histidine or Beta-Amyloid. Molecules 2022; 27:molecules27238334. [PMID: 36500427 PMCID: PMC9735935 DOI: 10.3390/molecules27238334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/20/2022] [Accepted: 11/22/2022] [Indexed: 12/05/2022] Open
Abstract
The anomalous interaction between metal ions and the peptide beta-amyloid is one of the hallmarks of Alzheimer's disease. Metal-binding biopolymers, including polysaccharides, can elucidate the fundamental aspects of metal ions' interactions with biological tissue and their interplay in Alzheimer's disease. This work focuses on the role of the alginate composition on Cu(II) adsorption in the presence of histidine or β-amyloid, the peptide associated with the progression of Alzheimer's disease. Alginate samples with different mannuronic/guluronic (M/G) ratios led to similar Cu(II) adsorption capacities, following the Langmuir isotherm and the pseudo-second-order adsorption kinetic models. Although the presence of histidine produced up to a 20% reduction in the copper adsorption capacity in guluronic-rich alginate samples (M/G~0.61), they presented stable bidentate chelation of the metallic ion. Chemical analyses (FTIR and XPS) demonstrated the role of hydroxyl and carboxyl groups in copper ion chelation, whereas both crystallinity and morphology analyses indicated the prevalence of histidine interaction with guluronic-rich alginate. Similar results were observed for Cu(II) adsorption in alginate beads in the presence of beta-amyloid and histidine, suggesting that the alginate/histidine system is a simple yet representative model to probe the application of biopolymers to metal ion uptake in the presence of biological competitors.
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3
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Micera A, Bruno L, Cacciamani A, Rongioletti M, Squitti R. Alzheimer's Disease and Retinal Degeneration: A Glimpse at Essential Trace Metals in Ocular Fluids and Tissues. Curr Alzheimer Res 2020; 16:1073-1083. [PMID: 31642780 DOI: 10.2174/1567205016666191023114015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 09/28/2019] [Accepted: 10/21/2019] [Indexed: 01/19/2023]
Abstract
BACKGROUND Life expectancy is increasing all over the world, although neurodegenerative disorders might drastically affect the individual activity of aged people. Of those, Alzheimer's Disease (AD) is one of the most social-cost age-linked diseases of industrialized countries. To date, retinal diseases seem to be more common in the developing world and characterize principally aged people. Agerelated Macular Degeneration (AMD) is a late-onset, neurodegenerative retinal disease that shares several clinical and pathological features with AD, including stress stimuli such as oxidative stress, inflammation and amyloid formations. METHODS In both diseases, the detrimental intra/extra-cellular deposits have many similarities. Aging, hypercholesterolemia, hypertension, obesity, arteriosclerosis and smoking are risk factors to develop both diseases. Cellular aging routes have similar organelle and signaling patterns in retina and brain. The possibility to find out new research strategies represent a step forward to disclose potential treatment for both of them. Essential trace metals play critical roles in both physiological and pathological condition of retina, optic nerve and brain, by influencing metabolic processes chiefly upon complex multifactorial pathogenesis. CONCLUSION Hence, this review addresses current knowledge about some up-to-date investigated essential trace metals associated with AD and AMD. Changes in the levels of systemic and ocular fluid essential metals might reflect the early stages of AMD, possibly disclosing neurodegeneration pathways shared with AD, which might open to potential early detection.
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Affiliation(s)
- Alessandra Micera
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Rome, Italy
| | - Luca Bruno
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Rome, Italy
| | - Andrea Cacciamani
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Rome, Italy
| | - Mauro Rongioletti
- Department of Laboratory Medicine, Research and Development Division, San Giovanni Calibita, Fatebenefratelli Hospital, Isola Tiberina, Rome, Italy
| | - Rosanna Squitti
- IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, BS, Italy
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4
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Morante S, La Penna G, Rossi G, Stellato F. SARS-CoV-2 Virion Stabilization by Zn Binding. Front Mol Biosci 2020; 7:222. [PMID: 33195401 PMCID: PMC7533540 DOI: 10.3389/fmolb.2020.00222] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 08/07/2020] [Indexed: 12/18/2022] Open
Abstract
Zinc plays a crucial role in the process of virion maturation inside the host cell. The accessory Cys-rich proteins expressed in SARS-CoV-2 by genes ORF7a and ORF8 are likely involved in zinc binding and in interactions with cellular antigens activated by extensive disulfide bonds. In this report we provide a proof of concept for the feasibility of a structural study of orf7a and orf8 proteins. A conceivable hypothesis is that lack of cellular zinc, or substitution thereof, might lead to a significant slowing down of viral maturation.
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Affiliation(s)
- Silvia Morante
- Dipartimento di Fisica, Università di Roma "Tor Vergata", Rome, Italy.,INFN, Sezione di Roma Tor Vergata, Rome, Italy
| | - Giovanni La Penna
- INFN, Sezione di Roma Tor Vergata, Rome, Italy.,CNR, Insitute of Chemistry of Organometallic Compounds, Firenze, Italy
| | - Giancarlo Rossi
- Dipartimento di Fisica, Università di Roma "Tor Vergata", Rome, Italy.,INFN, Sezione di Roma Tor Vergata, Rome, Italy.,Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", Rome, Italy
| | - Francesco Stellato
- Dipartimento di Fisica, Università di Roma "Tor Vergata", Rome, Italy.,INFN, Sezione di Roma Tor Vergata, Rome, Italy
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5
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Pushie MJ, Stefaniak E, Sendzik MR, Sokaras D, Kroll T, Haas KL. Using N-Terminal Coordination of Cu(II) and Ni(II) to Isolate the Coordination Environment of Cu(I) and Cu(II) Bound to His13 and His14 in Amyloid-β(4-16). Inorg Chem 2019; 58:15138-15154. [PMID: 31657204 DOI: 10.1021/acs.inorgchem.9b01940] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The amyloid-β (Aβ) peptide is a cleavage product of the amyloid precursor protein and has been implicated as a central player in Alzheimer's disease. The N-terminal end of Aβ is variable, and different proportions of these variable-length Aβ peptides are present in healthy individuals and those with the disease. The N-terminally truncated form of Aβ starting at position 4 (Aβ4-x) has a His residue as the third amino acid (His6 using the formal Aβ numbering). The N-terminal sequence Xaa-Xaa-His is known as an amino terminal copper and nickel binding motif (ATCUN), which avidly binds Cu(II). This motif is not present in the commonly studied Aβ1-x peptides. In addition to the ATCUN site, Aβ4-x contains an additional metal binding site located at the tandem His residues (bis-His at His13 and 14) which is also found in other isoforms of Aβ. Using the ATCUN and bis-His motifs, the Aβ4-x peptide is capable of binding multiple metal ions simultaneously. We confirm that Cu(II) bound to this particular ATCUN site is redox silent, but the second Cu(II) site is redox active and can be readily reduced with ascorbate. We have employed surrogate metal ions to block copper coordination at the ATCUN or the tandem His site in order to isolate spectral features of the copper coordination environment for structural characterization using extended X-ray absorption fine structure (EXAFS) spectroscopy. This approach reveals that each copper coordination environment is independent in the Cu2Aβ4-x state. The identification of two functionally different copper binding environments within the Aβ4-x sequence may have important implications for this peptide in vivo.
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Affiliation(s)
- M Jake Pushie
- Department of Surgery , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E5 , Canada
| | - 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
| | - Madison R Sendzik
- Department of Chemistry and Physics , Saint Mary's College , Notre Dame , Indiana 46556 , United States
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
| | - Kathryn L Haas
- Department of Chemistry and Physics , Saint Mary's College , Notre Dame , Indiana 46556 , United States
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6
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Arrigoni F, Prosdocimi T, Mollica L, De Gioia L, Zampella G, Bertini L. Copper reduction and dioxygen activation in Cu-amyloid beta peptide complexes: insight from molecular modelling. Metallomics 2019; 10:1618-1630. [PMID: 30345437 DOI: 10.1039/c8mt00216a] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) involves a number of factors including an anomalous interaction of copper with the amyloid peptide (Aβ), inducing oxidative stress with radical oxygen species (ROS) production through a three-step cycle in which O2 is gradually reduced to superoxide, oxygen peroxide and finally OH radicals. The purpose of this work has been to investigate the reactivity of 14 different Cu(ii)-Aβ coordination models with the aim of identifying on an energy basis (Density Functional Theory (DFT) and classical Molecular Dynamics (MD)) the redox competent form(s). Accordingly, we have specifically focused on the first three steps of the cycle, i.e. ascorbate binding to Cu(ii), Cu(ii) → Cu(i) reduction and O2 reduction to O2-. Compared to the recent literature, our results broaden the set of possible redox competent metallopeptide forms responsible for ROS production. Indeed, in addition to the three-coordinated species containing one His ligand, a N-terminal amine group and the carboxylate side chain of the Asp1 residue of Aβ already proposed, we found two other Cu-Aβ coordination modes involving two histidines.
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Affiliation(s)
- Federica Arrigoni
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy.
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7
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Opare SKA, Rauk A. Pseudopeptide Designed to Inhibit Oligomerization and Redox Chemistry in Alzheimer’s Disease. J Phys Chem B 2019; 123:5206-5215. [DOI: 10.1021/acs.jpcb.9b01665] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stanley K. A. Opare
- Department of Chemistry, The University of Calgary, Calgary, Alberta Canada, T2N 1N4
| | - Arvi Rauk
- Department of Chemistry, The University of Calgary, Calgary, Alberta Canada, T2N 1N4
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8
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Rana M, Sharma AK. Cu and Zn interactions with Aβ peptides: consequence of coordination on aggregation and formation of neurotoxic soluble Aβ oligomers. Metallomics 2019; 11:64-84. [DOI: 10.1039/c8mt00203g] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The coordination chemistry of transition metal ions (Fe, Cu, Zn) with the amyloid-β (Aβ) peptides has attracted a lot of attention in recent years due to its repercussions in Alzheimer's disease (AD).
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Affiliation(s)
- Monika Rana
- Department of Chemistry
- Central University of Rajasthan
- Ajmer 305817
- India
| | - Anuj Kumar Sharma
- Department of Chemistry
- Central University of Rajasthan
- Ajmer 305817
- India
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9
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Understanding the Exceptional Properties of Nitroacetamides in Water: A Computational Model Including the Solvent. Molecules 2018; 23:molecules23123308. [PMID: 30551625 PMCID: PMC6320899 DOI: 10.3390/molecules23123308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 12/07/2018] [Accepted: 12/10/2018] [Indexed: 11/22/2022] Open
Abstract
Proton transfer in water involving C–H bonds is a challenge and nitro compounds have been studied for many years as good examples. The effect of substituents on acidity of protons geminal to the nitro group is exploited here with new pKa measurements and electronic structure models, the latter including explicit water environment. Substituents with the amide moiety display an exceptional combination of acidity and solubility in water. In order to find a rationale for the unexpected pKa changes in the (ZZ′)NCO- substituents, we measured and modeled the pKa with Z=Z′=H and Z=Z′=methyl. The dominant contribution to the observed pKa can be understood with advanced computational experiments, where the geminal proton is smoothly moved to the solvent bath. These models, mostly based on density-functional theory (DFT), include the explicit solvent (water) and statistical thermal fluctuations. As a first approximation, the change of pKa can be correlated with the average energy difference between the two tautomeric forms (aci and nitro, respectively). The contribution of the solvent molecules interacting with the solute to the proton transfer mechanism is made evident.
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10
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Mehrazma B, Opare S, Petoyan A, Rauk A. d-Amino Acid Pseudopeptides as Potential Amyloid-Beta Aggregation Inhibitors. Molecules 2018; 23:E2387. [PMID: 30231520 PMCID: PMC6225248 DOI: 10.3390/molecules23092387] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/06/2018] [Accepted: 09/14/2018] [Indexed: 12/18/2022] Open
Abstract
A causative factor for neurotoxicity associated with Alzheimer's disease is the aggregation of the amyloid-β (Aβ) peptide into soluble oligomers. Two all d-amino acid pseudo-peptides, SGB1 and SGD1, were designed to stop the aggregation. Molecular dynamics (MD) simulations have been carried out to study the interaction of the pseudo-peptides with both Aβ13⁻23 (the core recognition site of Aβ) and full-length Aβ1⁻42. Umbrella sampling MD calculations have been used to estimate the free energy of binding, ∆G, of these peptides to Aβ13⁻23. The highest ∆Gbinding is found for SGB1. Each of the pseudo-peptides was also docked to Aβ1⁻42 and subjected up to seven microseconds of all atom molecular dynamics simulations. The resulting structures lend insight into how the dynamics of Aβ1⁻42 are altered by complexation with the pseudo-peptides and confirmed that SGB1 may be a better candidate for developing into a drug to prevent Alzheimer's disease.
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Affiliation(s)
- Banafsheh Mehrazma
- Department of Chemistry, University of Calgary; Calgary, AB T2N 1N4, Canada.
| | - Stanley Opare
- Department of Chemistry, University of Calgary; Calgary, AB T2N 1N4, Canada.
| | - Anahit Petoyan
- Department of Chemistry, University of Calgary; Calgary, AB T2N 1N4, Canada.
| | - Arvi Rauk
- Department of Chemistry, University of Calgary; Calgary, AB T2N 1N4, Canada.
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11
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La Penna G, Li MS. Towards High-Throughput Modelling of Copper Reactivity Induced by Structural Disorder in Amyloid Peptides. Chemistry 2018; 24:5259-5270. [DOI: 10.1002/chem.201704654] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Indexed: 12/26/2022]
Affiliation(s)
- Giovanni La Penna
- National Research Council (CNR); Institute for Chemistry of Organometallic Compounds (ICCOM); via Madonna del Piano 10 50019 Sesto Fiorentino, Firenze Italy
| | - Mai Suan Li
- Polish Academy of Sciences; Institute of Physics; al. Lotników 32/46 02-668 Warsaw Poland
- Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12; Ho Chi Minh City Vietnam
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12
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Affiliation(s)
- Stanley K. A. Opare
- Department of Chemistry, University of Calgary, 2500 University Drive Northwest, Calgary, Alberta, Canada T2N 1N4
| | - Arvi Rauk
- Department of Chemistry, University of Calgary, 2500 University Drive Northwest, Calgary, Alberta, Canada T2N 1N4
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13
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Li C, Guo XD, Lei M, Wu JY, Jin JZ, Shi XF, Zhu ZY, Rukachaisirikul V, Hu LH, Wen TQ, Shen X. Thamnolia vermicularis extract improves learning ability in APP/PS1 transgenic mice by ameliorating both Aβ and Tau pathologies. Acta Pharmacol Sin 2017; 38:9-28. [PMID: 27694908 PMCID: PMC5220549 DOI: 10.1038/aps.2016.94] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 07/24/2016] [Indexed: 12/25/2022] Open
Abstract
Considering the complicated pathogenesis of Alzheimer's disease (AD), multi-targets have become a focus in the discovery of drugs for treatment of this disease. In the current work, we established a multi-target strategy for discovering active reagents capable of suppressing both Aβ level and Tau hyperphosphorylation from natural products, and found that the ethanol extract of Thamnolia vermicularis (THA) was able to improve learning ability in APP/PS1 transgenic mice by inhibiting both Aβ levels and Tau hyperphosphorylation. SH-SY5Y and CHO-APP/BACE1 cells and primary astrocytes were used in cell-based assays. APP/PS1 transgenic mice [B6C3-Tg(APPswe, PS1dE9)] were administered THA (300 mg·kg-1·d-1, ig) for 100 d. After the administration was completed, the learning ability of the mice was detected using a Morris water maze (MWM) assay; immunofluorescence staining, Congo red staining and Thioflavine S staining were used to detect the senile plaques in the brains of the mice. ELISA was used to evaluate Aβ and sAPPβ contents, and Western blotting and RT-PCR were used to investigate the relevant signaling pathway regulation in response to THA treatment. In SH-SY5Y cells, THΑ (1, 10, 20 μg/mL) significantly stimulated PI3K/AKT/mTOR and AMPK/raptor/mTOR signaling-mediated autophagy in the promotion of Aβ clearance as both a PI3K inhibitor and an AMPK indirect activator, and restrained Aβ production as a suppressor against PERK/eIF2α-mediated BACE1 expression. Additionally, THA functioned as a GSK3β inhibitor with an IC50 of 1.32±0.85 μg/mL, repressing Tau hyperphosphorylation. Similar effects on Aβ accumulation and Tau hyperphosphorylation were observed in APP/PS1 transgenic mice treated with THA. Furthermore, administration of THA effectively improved the learning ability of APP/PS1 transgenic mice, and markedly reduced the number of senile plaques in their hippocampus and cortex. The results highlight the potential of the natural product THA for the treatment of AD.
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Affiliation(s)
- Cong Li
- School of Life Sciences, Shanghai University, Shanghai 200444, China
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xiao-dan Guo
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Min Lei
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jia-yi Wu
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jia-zhen Jin
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xiao-fan Shi
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Zhi-yuan Zhu
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Vatcharin Rukachaisirikul
- Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand
| | - Li-hong Hu
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Tie-qiao Wen
- School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Xu Shen
- School of Life Sciences, Shanghai University, Shanghai 200444, China
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
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14
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On the generation of OH(·) radical species from H2O2 by Cu(I) amyloid beta peptide model complexes: a DFT investigation. J Biol Inorg Chem 2015; 21:197-212. [PMID: 26711660 DOI: 10.1007/s00775-015-1322-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 12/08/2015] [Indexed: 12/27/2022]
Abstract
According to different studies, the interaction between amyloid β-peptide (Aβ) and copper ions could yield radical oxygen species production, in particular the highly toxic hydroxyl radical OH(·) that is suspected to contribute to Alzheimer's disease pathogenesis. Despite intensive experimental and computational studies, the nature of the interaction between copper and Aβ peptide, as well as the redox reactivity of the system, are still matter of debate. It was proposed that in Cu(II) → Cu(I) reduction the complex Cu(II)-Aβ could follow a multi-step conformational change with redox active intermediates that may be responsible for OH(·) radical production from H2O2 through a Fenton-like process. The purpose of this work is to evaluate, using ab initio Density Functional Theory computations, the reactivity of different Cu(I)-Aβ coordination modes proposed in the literature, in terms of OH(·) production. For each coordination model, we considered the corresponding H2O2 adduct and performed a potential energy surface scan along the reaction coordinate of O-O bond dissociation of the peroxide, resulting in the production of OH(·) radical, obtaining reaction profiles for the evaluation of the energetic of the process. This procedure allowed us to confirm the hypothesis according to which the most populated Cu(I)-Aβ two-histidine coordination is not able to perform efficiently H2O2 reduction, while a less populated three-coordinated form would be responsible for the OH(·) production. We show that coordination modes featuring a third nitrogen containing electron-donor ligand (an imidazole ring of an histidine residue is slightly favored over the N-terminal amine group) are more active towards H2O2 reduction.
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15
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Alí-Torres J, Mirats A, Maréchal JD, Rodríguez-Santiago L, Sodupe M. 3D structures and redox potentials of Cu2+-Aβ(1-16) complexes at different pH: a computational study. J Phys Chem B 2014; 118:4840-50. [PMID: 24738872 DOI: 10.1021/jp5019718] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Oxidative stress induced by redox-active metal cations such as Cu(2+) is a key event in the development of Alzheimer's disease. A detailed knowledge of the structure of Cu(2+)-Aβ complex is thus important to get a better understanding of this critical process. In the present study, we use a computational approach that combines homology modeling with quantum-mechanics-based methods to determine plausible 3D structures of Cu(2+)-Aβ(1-16) complexes that enclose the different metal coordination spheres proposed experimentally at different pH values. With these models in hand, we determine their standard reduction potential (SRP) with the aim of getting new insights into the relation between the structure of these complexes and their redox behavior. Results show that in all cases copper reduction induces CObackbone decoordination, which, for distorted square planar structures in the oxidized state (Ia_δδ, IIa_εδε, IIa_εεε, and IIc_ε), leads to tricoordinated species. For the pentacoordinated structural candidate Ib_δε with Glu11 at the apical position, the reduction leads to a distorted tetrahedral structure. The present results highlight the importance of the nature of the ligands on the SRP. The computed values (with respect to the standard hydrogen electrode) for complexes enclosing negatively charged ligands in the coordination sphere (from -0.81 to -0.12 V) are significantly lower than those computed for models involving neutral ligands (from 0.19 to 0.28 V). Major geometry changes induced by reduction, on both the metal site and the peptide configuration, are discussed as well as their possible influence in the formation of reactive oxygen species.
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Affiliation(s)
- Jorge Alí-Torres
- Departament de Química, Universitat Autònoma de Barcelona , 08193 Bellaterra, Barcelona, Spain
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16
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Maiorana A, Marino T, Minicozzi V, Morante S, Russo N. A micro-environmental study of the Zn+2–Aβ1–16 structural properties. Biophys Chem 2013; 182:86-93. [DOI: 10.1016/j.bpc.2013.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/14/2013] [Accepted: 07/07/2013] [Indexed: 11/29/2022]
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17
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Characterization of the polymorphic states of copper(II)-bound Aβ(1-16) peptides by computational simulations. J Comput Chem 2013; 34:2524-36. [DOI: 10.1002/jcc.23416] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/23/2013] [Accepted: 08/01/2013] [Indexed: 01/07/2023]
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18
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Solution and solid state study of copper(II) ternary complexes with some dipeptides presence in Aβ-42 peptide and methionine. Polyhedron 2013. [DOI: 10.1016/j.poly.2013.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Advances in electrochemical detection for study of neurodegenerative disorders. Anal Bioanal Chem 2013; 405:5725-41. [DOI: 10.1007/s00216-013-6904-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 03/05/2013] [Accepted: 03/06/2013] [Indexed: 12/30/2022]
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20
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Designing a functional type 2 copper center that has nitrite reductase activity within α-helical coiled coils. Proc Natl Acad Sci U S A 2012; 109:21234-9. [PMID: 23236170 DOI: 10.1073/pnas.1212893110] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One of the ultimate objectives of de novo protein design is to realize systems capable of catalyzing redox reactions on substrates. This goal is challenging as redox-active proteins require design considerations for both the reduced and oxidized states of the protein. In this paper, we describe the spectroscopic characterization and catalytic activity of a de novo designed metallopeptide Cu(I/II)(TRIL23H)(3)(+/2+), where Cu(I/II) is embeded in α-helical coiled coils, as a model for the Cu(T2) center of copper nitrite reductase. In Cu(I/II)(TRIL23H)(3)(+/2+), Cu(I) is coordinated to three histidines, as indicated by X-ray absorption data, and Cu(II) to three histidines and one or two water molecules. Both ions are bound in the interior of the three-stranded coiled coils with affinities that range from nano- to micromolar [Cu(II)], and picomolar [Cu(I)]. The Cu(His)(3) active site is characterized in both oxidation states, revealing similarities to the Cu(T2) site in the natural enzyme. The species Cu(II)(TRIL23H)(3)(2+) in aqueous solution can be reduced to Cu(I)(TRIL23H)(3)(+) using ascorbate, and reoxidized by nitrite with production of nitric oxide. At pH 5.8, with an excess of both the reductant (ascorbate) and the substrate (nitrite), the copper peptide Cu(II)(TRIL23H)(3)(2+) acts as a catalyst for the reduction of nitrite with at least five turnovers and no loss of catalytic efficiency after 3.7 h. The catalytic activity, which is first order in the concentration of the peptide, also shows a pH dependence that is described and discussed.
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Alies B, Bijani C, Sayen S, Guillon E, Faller P, Hureau C. Copper coordination to native N-terminally modified versus full-length amyloid-β: second-sphere effects determine the species present at physiological pH. Inorg Chem 2012; 51:12988-3000. [PMID: 23150940 DOI: 10.1021/ic302097d] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Alzheimer's disease is characterized by senile plaques in which metallic ions (copper, zinc, and iron) are colocalized with amyloid-β peptides of different sequences in aggregated forms. In addition to the full-length peptides (Aβ1-40/42), N-terminally truncated Aβ3-40/42 forms and their pyroglutamate counterparts, Aβp3-40/42, have been proposed to play key features in the aggregation process, leading to the senile plaques. Furthermore, they have been shown to be more toxic than the full-length Aβ, which made them central targets for therapeutic approaches. In order to better disentangle the possible role of metallic ions in the aggregation process, copper(II) coordination to the full-length amyloid peptides has been extensively studied in the last years. However, regarding the N-terminally modified forms at position 3, very little is known. Therefore, copper(I) and copper(II) coordination to those peptides have been investigated in the present report using a variety of complementary techniques and as a function of pH. Copper(I) coordination is not affected by the N-terminal modifications. In contrast, copper(II) coordination is different from that previously reported for the full-length peptide. In the case of the pyroglutamate form, this is due to preclusion of N-terminal amine binding. In the case of the N-terminally truncated form, alteration in copper(II) coordination is caused by second-sphere effects that impact the first binding shell and the pH-dependent repartition of the various [Cu(peptide)] complexes. Such second-sphere effects are anticipated to apply to a variety of metal ions and peptides, and their importance on changing the first binding shell has not been fully recognized yet.
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Affiliation(s)
- Bruno Alies
- Laboratoire de Chimie de Coordination (LCC), CNRS, 205 route de Narbonne, F-31077 Toulouse, France.
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Eskici G, Axelsen PH. Copper and Oxidative Stress in the Pathogenesis of Alzheimer’s Disease. Biochemistry 2012; 51:6289-311. [DOI: 10.1021/bi3006169] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Gözde Eskici
- Departments of Pharmacology, Biochemistry and Biophysics,
and Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United
States
| | - Paul H. Axelsen
- Departments of Pharmacology, Biochemistry and Biophysics,
and Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United
States
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23
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Solution and solid state study of copper(II) ternary complexes containing amino acids of interest for brain biochemistry – 2: Homocysteine with aspartate, glutamate or methionine. Inorganica Chim Acta 2012. [DOI: 10.1016/j.ica.2012.01.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Arena G, Pappalardo G, Sovago I, Rizzarelli E. Copper(II) interaction with amyloid-β: Affinity and speciation. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2011.07.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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25
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Azimi S, Rauk A. On the involvement of copper binding to the N-terminus of the amyloid Beta Peptide of Alzheimer's disease: a computational study on model systems. Int J Alzheimers Dis 2011; 2011:539762. [PMID: 22191059 PMCID: PMC3235578 DOI: 10.4061/2011/539762] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 08/04/2011] [Accepted: 08/16/2011] [Indexed: 12/27/2022] Open
Abstract
Density functional and second order Moller-Plesset perturbation theoretical methods, coupled with a polarizable continuum model of water, were applied to determine the structures, binding affinities, and reduction potentials of Cu(II) and Cu(I) bound to models of the Asp1, Ala2, His6, and His13His14 regions of the amyloid beta peptide of Alzheimer's disease. The results indicate that the N-terminal Asp binds to Cu(II) together with His6 and either His13 or His14 to form the lower pH Component I of Aβ. Component II of Aβ is the complex between Cu(II) and His6, His13, and His14, to which an amide O (of Ala2) is also coordinated. Asp1 does not bind to Cu(II) if three His residues are attached nor to any Cu(I) species to which one or more His residues are bound. The most stable Cu(I) species is one in which Cu(I) bridges the Nδ of His13 and His14 in a linear fashion. Cu(I) binds more strongly to Aβ than does Cu(II). The computed reduction potential that closely matches the experimental value for Cu(II)/Aβ corresponds to reduction of Component II (without Ala2) to the Cu(I) complex after endergonic attachment of His6.
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Affiliation(s)
- Samira Azimi
- Department of Chemistry, The University of Calgary, Calgary AB, Canada T2N 1N4
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26
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Furlan S, La Penna G. The mechanism of hydrogen uptake in [NiFe] hydrogenase: first-principles molecular dynamics investigation of a model compound. J Biol Inorg Chem 2011; 17:149-64. [DOI: 10.1007/s00775-011-0838-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 08/15/2011] [Indexed: 10/17/2022]
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Computational insights into the development of novel therapeutic strategies for Alzheimer's disease. Future Med Chem 2011; 1:119-35. [PMID: 21426072 DOI: 10.4155/fmc.09.10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND β-amyloidosis and oxidative stress have been implicated as root causes of Alzheimer's disease (AD). Current potential therapeutic strategies for the treatment of AD include inhibition of amyloid β (Aβ) production, stimulation of Aβ degradation and prevention of Aβ oligomerization. However, efforts in this direction are hindered by the lack of understanding of the biochemical processes occurring at the atomic level in AD. DISCUSSION A radically different approach to achieve this goal would be the application of comprehensive theoretical and computational techniques such as molecular dynamics, quantum mechanics, hybrid quantum mechanics/molecular mechanics, bioinformatics and rotational spectroscopy to investigate complex chemical and physical processes in β-amyloidosis and the oxidative stress mechanism. CONCLUSION Results obtained from these studies will provide an atomic level understanding of biochemical processes occurring in AD and advance efforts to develop effective therapeutic strategies for this disease.
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Furlan S, Hureau C, Faller P, La Penna G. Modeling the Cu+ Binding in the 1−16 Region of the Amyloid-β Peptide Involved in Alzheimer’s Disease. J Phys Chem B 2010; 114:15119-33. [DOI: 10.1021/jp102928h] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Sara Furlan
- LCC (Laboratoire de Chimie de Coordination), CNRS, 205 route de Narbonne, F-31077 Toulouse, France; UPS, INPT, LCC, Université de Toulouse, F-31077 Toulouse, France; and ICCOM (Institute for Chemistry of Organo-metallic Compounds), CNR (National Research Council), via Madonna del Piano 10, I-50019 Sesto Fiorentino, Firenze, Italy
| | - Christelle Hureau
- LCC (Laboratoire de Chimie de Coordination), CNRS, 205 route de Narbonne, F-31077 Toulouse, France; UPS, INPT, LCC, Université de Toulouse, F-31077 Toulouse, France; and ICCOM (Institute for Chemistry of Organo-metallic Compounds), CNR (National Research Council), via Madonna del Piano 10, I-50019 Sesto Fiorentino, Firenze, Italy
| | - Peter Faller
- LCC (Laboratoire de Chimie de Coordination), CNRS, 205 route de Narbonne, F-31077 Toulouse, France; UPS, INPT, LCC, Université de Toulouse, F-31077 Toulouse, France; and ICCOM (Institute for Chemistry of Organo-metallic Compounds), CNR (National Research Council), via Madonna del Piano 10, I-50019 Sesto Fiorentino, Firenze, Italy
| | - Giovanni La Penna
- LCC (Laboratoire de Chimie de Coordination), CNRS, 205 route de Narbonne, F-31077 Toulouse, France; UPS, INPT, LCC, Université de Toulouse, F-31077 Toulouse, France; and ICCOM (Institute for Chemistry of Organo-metallic Compounds), CNR (National Research Council), via Madonna del Piano 10, I-50019 Sesto Fiorentino, Firenze, Italy
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29
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Pinto LD, Puppin PA, Behring VM, Flinker DH, Mercê ALR, Mangrich AS, Rey NA, Felcman J. Solution and solid state study of copper(II) ternary complexes containing amino acids of interest for brain biochemistry – 1: Aspartic or glutamic acids with methionine or cysteine. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2010.04.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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30
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On the metal ion (Zn2+, Cu2+) coordination with beta-amyloid peptide: DFT computational study. Interdiscip Sci 2010; 2:57-69. [DOI: 10.1007/s12539-010-0086-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 11/10/2009] [Accepted: 11/11/2009] [Indexed: 01/02/2023]
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31
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Epa VC, Streltsov VA, Varghese JN. Modelling Copper Binding to the Amyloid-β Peptide in Alzheimer. Aust J Chem 2010. [DOI: 10.1071/ch09454] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Oxidative modification due to reactive oxygen species generated by Cu2+ bound to the amyloid-β peptide may be one of the sources of neurodegeneration observed in Alzheimer’s disease. Understanding the structure and function of the copper binding site can assist in the design of effective therapeutics. This paper highlights some of the most significant recent developments in computational modelling studies of the structure of the binding site and reaction mechanisms of reactive oxygen species generation.
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32
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Palivan CG, Balasubramanian V, Goodman BA. Global Structure–Activity Analysis in Drug Development Illustrated for Active Cu/Zn Superoxide Dismutase Mimics. Eur J Inorg Chem 2009. [DOI: 10.1002/ejic.200900808] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Cornelia G. Palivan
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland, Fax: +41‐612673855
| | - Vimalkumar Balasubramanian
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland, Fax: +41‐612673855
| | - Bernard A. Goodman
- Department of Environmental Research, Austrian Research Center Seibersdorf, 2444 Seibersdorf, Austria
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33
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Brzyska M, Trzesniewska K, Wieckowska A, Szczepankiewicz A, Elbaum D. Electrochemical and conformational consequences of copper (Cu(I) and Cu(II)) binding to beta-amyloid(1-40). Chembiochem 2009; 10:1045-55. [PMID: 19263448 DOI: 10.1002/cbic.200800732] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Copper-induced structural rearrangements of Abeta40 structure and its redox properties are described in this study. Electrochemical and fluorescent methods are used to characterise the behaviour of Abeta-Cu species. The data suggest that time-dependent folding of Abeta-Cu species may cause changes in the redox potentials.Extracellular deposits of beta-amyloid (Abeta) into senile plaques are the major features observed in brains of Alzheimer's disease (AD) patients. A high concentration of copper has been associated with insoluble amyloid plaques. It is known that Abeta(1-40) can bind copper with high affinity, but electrochemical properties of Abeta(1-40)-Cu complexes are not well-characterised. In this study we demonstrate that complexation of copper (both as Cu(I) and Cu(II)) by Abeta(1-40) reduces the metal electrochemical activity. Formation of copper-Abeta(1-40) complexes is associated with alteration of the redox potential. The data reveal significant redox activity of fresh Abeta-copper solutions. However, copper-induced structural rearrangements of the peptide, documented by CD, correspond with time-dependent changes of formal reduction potentials (E(0')) of the complex. Fluorescent and electrochemical (cyclic voltammetry and differential pulse voltammetry) techniques suggest that reduction of the redox activity by Abeta-Cu complexes could be attributed to conformational changes that diminished copper accessibility to the external environment. According to our evidence, conformational rearrangements, induced by copper binding to amyloid, elongate the time necessary to attain the same beta-sheet content as for the metal-free peptide. Although the redox activity of Abeta-Cu complexes diminishes in a time-dependent manner, they are not completely devoid of toxicity as they destabilize red blood cells osmotic fragility, even after prolonged incubation.
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Affiliation(s)
- Maria Brzyska
- Department of Neurophysiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
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34
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Hewitt N, Rauk A. Mechanism of hydrogen peroxide production by copper-bound amyloid beta peptide: a theoretical study. J Phys Chem B 2009; 113:1202-9. [PMID: 19123835 DOI: 10.1021/jp807327a] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The amyloid beta peptide (Abeta) of Alzheimer's disease evolves hydrogen peroxide in vitro in the presence of Cu(II), external reducing agents, and molecular oxygen, without producing detectable amounts of the one-electron reduced intermediate, superoxide, O(2)(-*). The mechanism of this process was examined by ab initio computational chemistry techniques in systems that model the binding of Cu(II) to the His13His14 fragment of Abeta. The catalytic cycle begins with the reduction of the most stable Cu(II) complex to the most stable Cu(I) complex. This Cu(I) complex forms a Cu(II)-like adduct with (3)O(2) that cannot dissociate in water to yield O(2)(-*). However, it can be reduced by proton-coupled electron transfer to an adduct between HOO(-) and the Cu(II)-like complex, which in turn can be protonated. The protonated complex decomposes to yield H(2)O(2) by an associative-dissociative mechanism, thus completing the cycle.
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Affiliation(s)
- Nadine Hewitt
- Department of Chemistry, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3X7
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35
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36
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Faller P, Hureau C. Bioinorganic chemistry of copper and zinc ions coordinated to amyloid-β peptide. Dalton Trans 2009:1080-94. [DOI: 10.1039/b813398k] [Citation(s) in RCA: 423] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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37
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Shearer J, Szalai VA. The amyloid-beta peptide of Alzheimer's disease binds Cu(I) in a linear bis-his coordination environment: insight into a possible neuroprotective mechanism for the amyloid-beta peptide. J Am Chem Soc 2008; 130:17826-35. [PMID: 19035781 PMCID: PMC2935688 DOI: 10.1021/ja805940m] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Oxidative stress has been suggested to contribute to neuronal apoptosis associated with Alzheimer's disease (AD). Copper may participate in oxidative stress through redox-cycling between its +2 and +1 oxidation states to generate reactive oxygen species (ROS). In vitro, copper binds to the amyloid-beta peptide of AD, and in vivo, copper is associated with amyloid plaques characteristic of AD. As a result, the AbetaCu(I) complex may be a critical reactant involved in ROS associated with AD etiology. To characterize the AbetaCu(I) complex, we have pursued X-ray absorption (XAS) and electron paramagnetic resonance (EPR) spectroscopy of AbetaCu(II) and AbetaCu(I) (produced by ascorbate reduction of AbetaCu(II)). The AbetaCu(II) complex Cu K-edge XAS spectrum is indicative of a square-planar Cu(II) center with mixed N/O ligation. Multiple scattering analysis of the extended X-ray absorption fine structure (EXAFS) data for AbetaCu(II) indicates that two of the ligands are imidazole groups of histidine ligands, indicating a (N(Im))(2)(N/O)(2) Cu(II) ligation sphere for AbetaCu(II). After reduction of the AbetaCu(II) complex with ascorbate, the edge region decreases in energy by approximately 4 eV. The X-ray absorption near-edge spectrum region of AbetaCu(I) displays an intense pre-edge feature at 8984.1(2) eV. EXAFS data fitting yielded a two-coordinate geometry, with two imidazole ligands coordinated to Cu(I) at 1.877(2) A in a linear geometry. Ascorbate reduction of AbetaCu(II) under inert atmosphere and subsequent air oxidation of AbetaCu(I) to regenerate AbetaCu(II) was monitored by low-temperature EPR spectroscopy. Slow reappearance of the AbetaCu(II) EPR signal indicates that O(2) oxidation of the AbetaCu(I) complex is kinetically sluggish and Abeta damage is occurring following reoxidation of AbetaCu(I) by O(2). Together, these results lead us to hypothesize that Cu(I) is ligated by His13 and His14 in a linear coordination environment in Alphabeta, that Abeta may be playing a neuroprotective role, and that metal-mediated oxidative damage of Abeta occurs over multiple redox cycles.
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Affiliation(s)
- Jason Shearer
- Department of Chemistry/216, University of Nevada-Reno, 1664 N. Virginia St, Reno, NV 89557
| | - Veronika A. Szalai
- Department of Chemistry & Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250
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38
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Himes R, Park G, Siluvai G, Blackburn N, Karlin K. Structural Studies of Copper(I) Complexes of Amyloid-β Peptide Fragments: Formation of Two-Coordinate Bis(histidine) Complexes. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200803908] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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39
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Milko P, Roithová J, Tsierkezos N, Schröder D. The C-O stretch as an unprecedently large spectral marker for the electron transfer between Copper(II) and a phenolate anion. J Am Chem Soc 2008; 130:7186-7. [PMID: 18479087 DOI: 10.1021/ja801079r] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An unprecedented red shift of more than 200 cm(-1) in the vibrational frequency of the C-O bond in the [Cu(PhO)Ln]+ complex (PhO = phenoxy), dependent on the number n of additional ligands L, is reported. Upon change of n from 1 to 2, the spin density is shifted from the aromatic ring to the oxygen and copper atoms, which is reflected in the bond order and thus vibrational frequency of the C-O bond.
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Affiliation(s)
- Petr Milko
- Faculty of Science, Department of Organic Chemistry, Charles University in Prague, Hlavova 8, 12843 Prague 2, Czech Republic
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40
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Abstract
In this article, we support the case that the neurotoxic agent in Alzheimer's disease is a soluble aggregated form of the amyloid beta peptide (Abeta), probably complexed with divalent copper. The structure and chemical properties of the monomeric peptide and its Cu(ii) complex are discussed, as well as what little is known about the oligomeric species. Abeta oligomers are neurotoxic by a variety of mechanisms. They adhere to plasma and intracellular membranes and cause lesions by a combination of radical-initiated lipid peroxidation and formation of ion-permeable pores. In endothelial cells this damage leads to loss of integrity of the blood-brain barrier and loss of blood flow to the brain. At synapses, the oligomers close neuronal insulin receptors, mirroring the effects of Type II diabetes. In intracellular membranes, the most damaging effect is loss of calcium homeostasis. The oligomers also bind to a variety of substances, mostly with deleterious effects. Binding to cholesterol is accompanied by its oxidation to products that are themselves neurotoxic. Possibly most damaging is the binding to tau, and to several kinases, that results in the hyperphosphorylation of the tau and abrogation of its microtubule-supporting role in maintaining axon structure, leading to diseased synapses and ultimately the death of neurons. Several strategies are presented and discussed for the development of compounds that prevent the oligomerization of Abeta into the neurotoxic species.
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Affiliation(s)
- Arvi Rauk
- Department of Chemistry, University of Calgary, Calgary, AB T2N 1N4, Canada
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41
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Himes RA, Park GY, Siluvai GS, Blackburn NJ, Karlin KD. Structural studies of copper(I) complexes of amyloid-beta peptide fragments: formation of two-coordinate bis(histidine) complexes. Angew Chem Int Ed Engl 2008; 47:9084-7. [PMID: 18932185 PMCID: PMC2662329 DOI: 10.1002/anie.200803908] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Richard A. Himes
- Dept. of Chemistry, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218 (USA), E-mail:
| | - Ga Young Park
- Dept. of Chemistry, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218 (USA), E-mail:
| | - Gnana Sutha Siluvai
- Dept. of Environmental and Biomolecular Systems, OGI School of Science and Engineering at OHSU, Beaverton, OR, 97006 (USA)
| | - Ninian J. Blackburn
- Dept. of Environmental and Biomolecular Systems, OGI School of Science and Engineering at OHSU, Beaverton, OR, 97006 (USA)
| | - Kenneth D. Karlin
- Dept. of Chemistry, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218 (USA), E-mail:
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Comba P, Knoppe S, Martin B, Rajaraman G, Rolli C, Shapiro B, Stork T. Copper(II)-Mediated Aromaticortho-Hydroxylation: A Hybrid DFT and Ab Initio Exploration. Chemistry 2007; 14:344-57. [PMID: 17907133 DOI: 10.1002/chem.200700865] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mechanistic pathways for the aromatic hydroxylation by [CuII(L1)(TMAO)(O)](-) (L1=hippuric acid, TMAO=trimethylamine N-oxide), derived from the O--N bond homolysis of its [CuII(L1)(TMAO)2] precursor, were explored by using hybrid density functional theory (B3LYP) and highly correlated ab initio methods (QCISD and CCSD). Published experimental studies suggest that the catalytic reaction is triggered by a terminal copper-oxo species, and a detailed study of electronic structures, bonding, and energetics of the corresponding electromers is presented. Two pathways, a stepwise and a concerted reaction, were considered for the hydroxylation process. The results reveal a clear preference for the concerted pathway, in which the terminal oxygen atom directly attacks the carbon atom of the benzene ring, leading to the ortho-selectively hydroxylated product. Solvent effects were probed by using the PCM and CPCM solvation models, and the PCM model was found to perform better in the present case. Excellent agreement between the experimental and computational results was found, in particular also for changes in reactivity with derivatives of L1.
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Affiliation(s)
- Peter Comba
- Universität Heidelberg, Anorganisch-Chemisches Institut, INF 270, 69120 Heidelberg, Germany.
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