1
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Maity B, Kameyama S, Tian J, Pham TT, Abe S, Chatani E, Murata K, Ueno T. Fusion of amyloid beta with ferritin yields an isolated oligomeric beta-sheet-rich aggregate inside the ferritin cage. Biomater Sci 2024; 12:2408-2417. [PMID: 38511491 DOI: 10.1039/d4bm00173g] [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: 03/22/2024]
Abstract
Alzheimer's disease is a severe brain condition caused by the formation of amyloid plaques composed of amyloid beta (Aβ) peptides. These peptides form oligomers, protofibrils, and fibrils before deposition into amyloid plaques. Among these intermediates, Aβ oligomers (AβOs) were found to be the most toxic and therefore an appealing target for drug development and understanding their role in the disease. However, precise isolation and characterization of AβOs have proven challenging because AβOs tend to aggregate and form heterogeneous mixtures in solution. As a solution, we genetically fused the Aβ peptide with a ferritin monomer. Such fusion allowed the encapsulation of precisely 24 Aβ peptides inside the 24-mer ferritin cage. Using high-speed atomic force microscopy (HS-AFM), we disassembled ferritin and directly visualized the Aβ core enclosed within the cage. The thioflavin-T assay (ThT) and attenuated total reflection infrared spectroscopy (ATR-IR) revealed the presence of a β-sheet structure in the encapsulated oligomeric aggregate. Gallic acid, an amyloid inhibitor, can inhibit the fluorescence of ThT bound AβOs. Our approach represents a significant advancement in the isolation and characterization of β-sheet rich AβOs and is expected to be useful for future studies of other disordered peptides such as α-synuclein and tau.
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Affiliation(s)
- Basudev Maity
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho, 4259, Midori-ku, Yokohama 226 8501, Japan.
| | - Shiori Kameyama
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho, 4259, Midori-ku, Yokohama 226 8501, Japan.
| | - Jiaxin Tian
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho, 4259, Midori-ku, Yokohama 226 8501, Japan.
| | - Thuc Toan Pham
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho, 4259, Midori-ku, Yokohama 226 8501, Japan.
| | - Satoshi Abe
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho, 4259, Midori-ku, Yokohama 226 8501, Japan.
| | - Eri Chatani
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Hyogo 657-8501, Japan
| | - Kazuyoshi Murata
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institute for Natural Sciences, Okazaki, Aichi, 444-8585, Japan
- National Institute for Physiological Sciences (NIPS), National Institute for Natural Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Takafumi Ueno
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho, 4259, Midori-ku, Yokohama 226 8501, Japan.
- Living Systems Materialogy (LiSM) Research Group, International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama 226-8501, Japan
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2
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Alfano C, Fichou Y, Huber K, Weiss M, Spruijt E, Ebbinghaus S, De Luca G, Morando MA, Vetri V, Temussi PA, Pastore A. Molecular Crowding: The History and Development of a Scientific Paradigm. Chem Rev 2024; 124:3186-3219. [PMID: 38466779 PMCID: PMC10979406 DOI: 10.1021/acs.chemrev.3c00615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 02/13/2024] [Accepted: 02/26/2024] [Indexed: 03/13/2024]
Abstract
It is now generally accepted that macromolecules do not act in isolation but "live" in a crowded environment, that is, an environment populated by numerous different molecules. The field of molecular crowding has its origins in the far 80s but became accepted only by the end of the 90s. In the present issue, we discuss various aspects that are influenced by crowding and need to consider its effects. This Review is meant as an introduction to the theme and an analysis of the evolution of the crowding concept through time from colloidal and polymer physics to a more biological perspective. We introduce themes that will be more thoroughly treated in other Reviews of the present issue. In our intentions, each Review may stand by itself, but the complete collection has the aspiration to provide different but complementary perspectives to propose a more holistic view of molecular crowding.
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Affiliation(s)
- Caterina Alfano
- Structural
Biology and Biophysics Unit, Fondazione
Ri.MED, 90100 Palermo, Italy
| | - Yann Fichou
- CNRS,
Bordeaux INP, CBMN UMR 5248, IECB, University
of Bordeaux, F-33600 Pessac, France
| | - Klaus Huber
- Department
of Chemistry, University of Paderborn, 33098 Paderborn, Germany
| | - Matthias Weiss
- Experimental
Physics I, Physics of Living Matter, University
of Bayreuth, 95440 Bayreuth, Germany
| | - Evan Spruijt
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Simon Ebbinghaus
- Lehrstuhl
für Biophysikalische Chemie and Research Center Chemical Sciences
and Sustainability, Research Alliance Ruhr, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Giuseppe De Luca
- Dipartimento
di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | | | - Valeria Vetri
- Dipartimento
di Fisica e Chimica − Emilio Segrè, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | | | - Annalisa Pastore
- King’s
College London, Denmark
Hill Campus, SE5 9RT London, United Kingdom
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3
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John T, Piantavigna S, Dealey TJA, Abel B, Risselada HJ, Martin LL. Lipid oxidation controls peptide self-assembly near membranes through a surface attraction mechanism. Chem Sci 2023; 14:3730-3741. [PMID: 37035708 PMCID: PMC10074436 DOI: 10.1039/d3sc00159h] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/17/2023] [Indexed: 03/06/2023] Open
Abstract
The self-assembly of peptides into supramolecular structures has been linked to neurodegenerative diseases but has also been observed in functional roles. Peptides are physiologically exposed to crowded environments of biomacromolecules, and particularly cellular membrane lipids. Previous research has shown that membranes can both accelerate and inhibit peptide self-assembly. Here, we studied the impact of membrane models that mimic cellular oxidative stress and compared this to mammalian and bacterial membranes. Using molecular dynamics simulations and experiments, we propose a model that explains how changes in peptide-membrane binding, electrostatics, and peptide secondary structure stabilization determine the nature of peptide self-assembly. We explored the influence of zwitterionic (POPC), anionic (POPG) and oxidized (PazePC) phospholipids, as well as cholesterol, and mixtures thereof, on the self-assembly kinetics of the amyloid β (1-40) peptide (Aβ40), linked to Alzheimer's disease, and the amyloid-forming antimicrobial peptide uperin 3.5 (U3.5). We show that the presence of an oxidized lipid had similar effects on peptide self-assembly as the bacterial mimetic membrane. While Aβ40 fibril formation was accelerated, U3.5 aggregation was inhibited by the same lipids at the same peptide-to-lipid ratio. We attribute these findings and peptide-specific effects to differences in peptide-membrane adsorption with U3.5 being more strongly bound to the membrane surface and stabilized in an α-helical conformation compared to Aβ40. Different peptide-to-lipid ratios resulted in different effects. We found that electrostatic interactions are a primary driving force for peptide-membrane interaction, enabling us to propose a model for predicting how cellular changes might impact peptide self-assembly in vivo.
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Affiliation(s)
- Torsten John
- School of Chemistry, Monash University Clayton VIC 3800 Australia
- Leibniz Institute of Surface Engineering (IOM) Permoserstraße 15 04318 Leipzig Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Institute of Chemical Technology, Leipzig University Linnéstraße 3 04103 Leipzig Germany
| | | | - Tiara J A Dealey
- School of Chemistry, Monash University Clayton VIC 3800 Australia
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM) Permoserstraße 15 04318 Leipzig Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Institute of Chemical Technology, Leipzig University Linnéstraße 3 04103 Leipzig Germany
| | - Herre Jelger Risselada
- Leibniz Institute of Surface Engineering (IOM) Permoserstraße 15 04318 Leipzig Germany
- Institute for Theoretical Physics, Georg-August-Universität Göttingen Friedrich-Hund-Platz 1 37077 Göttingen Germany
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4
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Berlin E, Lizano-Fallas V, Carrasco del Amor A, Fresnedo O, Cristobal S. Nonionic Surfactants can Modify the Thermal Stability of Globular and Membrane Proteins Interfering with the Thermal Proteome Profiling Principles to Identify Protein Targets. Anal Chem 2023; 95:4033-4042. [PMID: 36779864 PMCID: PMC9979136 DOI: 10.1021/acs.analchem.2c04500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The membrane proteins are essential targets for understanding cellular function. The unbiased identification of membrane protein targets is still the bottleneck for a system-level understanding of cellular response to stimuli or perturbations. It has been suggested to enrich the soluble proteome with membrane proteins by introducing nonionic surfactants in the solubilization solution. This strategy aimed to simultaneously identify the globular and membrane protein targets by thermal proteome profiling principles. However, the thermal shift assay would surpass the cloud point temperature from the nonionic surfactants frequently utilized for membrane protein solubilization. It is expected that around the cloud point temperature, the surfactant micelles would suffer structural modifications altering protein solubility. Here, we show that the presence of nonionic surfactants can alter protein thermal stability from a mixed, globular, and membrane proteome. In the presence of surfactant micelles, the changes in protein solubility analyzed after the thermal shift assay was affected by the thermally dependent modification of the micellar size and its interaction with proteins. We demonstrate that the introduction of nonionic surfactants for the solubilization of membrane proteins is not compatible with the principles of target identification by thermal proteome profiling methodologies. Our results lead to exploring thermally independent strategies for membrane protein solubilization to assure confident membrane protein target identification. The proteome-wide thermal shift methods have already shown their capability to elucidate mechanisms of action from pharma, biomedicine, analytical chemistry, or toxicology, and finding strategies, free from surfactants, to identify membrane protein targets would be the next challenge.
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Affiliation(s)
- Emmanuel Berlin
- Department
of Biomedical and Clinical Sciences, Cell Biology, Faculty of Medicine, Linköping University, Linköping 581 85, Sweden
| | - Veronica Lizano-Fallas
- Department
of Biomedical and Clinical Sciences, Cell Biology, Faculty of Medicine, Linköping University, Linköping 581 85, Sweden
| | - Ana Carrasco del Amor
- Department
of Biomedical and Clinical Sciences, Cell Biology, Faculty of Medicine, Linköping University, Linköping 581 85, Sweden
| | - Olatz Fresnedo
- Department
of Physiology, Faculty of Medicine, and Nursing, University of the Basque Country UPV/EHU, Leioa 489 40, Spain
| | - Susana Cristobal
- Department
of Biomedical and Clinical Sciences, Cell Biology, Faculty of Medicine, Linköping University, Linköping 581 85, Sweden,Ikerbasque,
Basque Foundation for Sciences, Department of Physiology, Faculty
of Medicine, and Nursing, University of
the Basque Country UPV/EHU, Leioa 489 40, Spain,. Tel: +46-730385867
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5
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Wang S, Wang M, Han L, Sun Y, Cai W, Shao X. Insight into the stability of protein in confined environment through analyzing the structure of water by temperature-dependent near-infrared spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 267:120581. [PMID: 34776375 DOI: 10.1016/j.saa.2021.120581] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/13/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
To understand the stability of protein in confined environment, the near-infrared (NIR) spectra of aqueous solutions and reverse micelles (RMs) containing bovine serum albumin (BSA), human serum albumin (HSA) and ovalbumin (OVA) were measured at different temperature. With the resolution enhanced spectra calculated by continuous wavelet transform (CWT), the intensity change of the α-helix band at 4617 cm-1 with temperature shows a clear denaturation of the protein in aqueous solution but not in RMs. The effect of the confined environment on the stability of the proteins is indicated. More importantly, the intensity change of the spectral bands of water around 6956 and 6842 cm-1 provide an evidence for the denaturation, suggesting that water can be a probe exhibiting the structural change of proteins. Furthermore, comparing the spectral features of different water structures obtained by principal component analysis (PCA) from the spectra of RM with and without BSA, it is demonstrated that the bridging water connecting NH in protein and SO in the inner surface of RM may be the reason for the stabilization.
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Affiliation(s)
- Shiying Wang
- Research Center for Analytical Sciences, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin Key Laboratory of Biosensing and Molecular Recognition, State Key Laboratory of Medicinal Chemical Biology, Tianjin 300071, PR China
| | - Mian Wang
- Research Center for Analytical Sciences, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin Key Laboratory of Biosensing and Molecular Recognition, State Key Laboratory of Medicinal Chemical Biology, Tianjin 300071, PR China
| | - Li Han
- Research Center for Analytical Sciences, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin Key Laboratory of Biosensing and Molecular Recognition, State Key Laboratory of Medicinal Chemical Biology, Tianjin 300071, PR China
| | - Yan Sun
- Research Center for Analytical Sciences, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin Key Laboratory of Biosensing and Molecular Recognition, State Key Laboratory of Medicinal Chemical Biology, Tianjin 300071, PR China
| | - Wensheng Cai
- Research Center for Analytical Sciences, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin Key Laboratory of Biosensing and Molecular Recognition, State Key Laboratory of Medicinal Chemical Biology, Tianjin 300071, PR China
| | - Xueguang Shao
- Research Center for Analytical Sciences, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin Key Laboratory of Biosensing and Molecular Recognition, State Key Laboratory of Medicinal Chemical Biology, Tianjin 300071, PR China.
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6
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Zhang S, Guaglianone G, Morris MA, Yoo S, Howitz WJ, Xing L, Zheng JG, Jusuf H, Huizar G, Lin J, Kreutzer AG, Nowick JS. Expression of N-Terminal Cysteine Aβ 42 and Conjugation to Generate Fluorescent and Biotinylated Aβ 42. Biochemistry 2021; 60:1191-1200. [PMID: 33793198 PMCID: PMC9059633 DOI: 10.1021/acs.biochem.1c00105] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Fluorescent derivatives of the β-amyloid peptides (Aβ) are valuable tools for studying the interactions of Aβ with cells. Facile access to labeled expressed Aβ offers the promise of Aβ with greater sequence and stereochemical integrity, without impurities from amino acid deletion and epimerization. Here, we report methods for the expression of Aβ42 with an N-terminal cysteine residue, Aβ(C1-42), and its conjugation to generate Aβ42 bearing fluorophores or biotin. The methods rely on the hitherto unrecognized observation that expression of the Aβ(MC1-42) gene yields the Aβ(C1-42) peptide, because the N-terminal methionine is endogenously excised by Escherichia coli. Conjugation of Aβ(C1-42) with maleimide-functionalized fluorophores or biotin affords the N-terminally labeled Aβ42. The expression affords ∼14 mg of N-terminal cysteine Aβ from 1 L of bacterial culture. Subsequent conjugation affords ∼3 mg of labeled Aβ from 1 L of bacterial culture with minimal cost for labeling reagents. High-performance liquid chromatography analysis indicates the N-terminal cysteine Aβ to be >97% pure and labeled Aβ peptides to be 94-97% pure. Biophysical studies show that the labeled Aβ peptides behave like unlabeled Aβ and suggest that labeling of the N-terminus does not substantially alter the properties of the Aβ. We further demonstrate applications of the fluorophore-labeled Aβ peptides by using fluorescence microscopy to visualize their interactions with mammalian cells and bacteria. We anticipate that these methods will provide researchers convenient access to useful N-terminally labeled Aβ, as well as Aβ with an N-terminal cysteine that enables further functionalization.
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Affiliation(s)
- Sheng Zhang
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Gretchen Guaglianone
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Michael A. Morris
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Stan Yoo
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - William J. Howitz
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Li Xing
- Irvine Materials Research Institute (IMRI), University of California-Irvine, Irvine, California 92697-2575, United States
| | - Jian-Guo Zheng
- Irvine Materials Research Institute (IMRI), University of California-Irvine, Irvine, California 92697-2575, United States
| | - Hannah Jusuf
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Grace Huizar
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Jonathan Lin
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Adam G. Kreutzer
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - James S. Nowick
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
- Department of Pharmaceutical Sciences, University of California-Irvine, Irvine, California 92697-2025, United States
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7
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Trumbore CN. Shear-Induced Amyloid Formation in the Brain: III. The Roles of Shear Energy and Seeding in a Proposed Shear Model. J Alzheimers Dis 2019; 65:47-70. [PMID: 30040710 PMCID: PMC6087447 DOI: 10.3233/jad-171003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
If cerebrospinal and interstitial fluids move through very narrow brain flow channels, these restrictive surroundings generate varying levels of fluid shear and different shear rates, and dissolved amyloid monomers absorb different shear energies. It is proposed that dissolved amyloid-β protein (Aβ) and other amyloid monomers undergo shear-induced conformational changes that ultimately lead to amyloid monomer aggregation even at very low brain flow and shear rates. Soluble Aβ oligomers taken from diseased brains initiate in vivo amyloid formation in non-diseased brains. The brain environment is apparently responsible for this result. A mechanism involving extensional shear is proposed for the formation of a seed Aβ monomer molecule that ultimately promotes templated conformational change of other Aβ molecules. Under non-quiescent, non-equilibrium conditions, gentle extensional shear within the brain parenchyma, and perhaps even during laboratory preparation of Aβ samples, may be sufficient to cause subtle conformational changes in these monomers. These result from brain processes that significantly lower the high activation energy predicted for the quiescent Aβ dimerization process. It is further suggested that changes in brain location and changes brought about by aging expose Aβ molecules to different shear rates, total shear, and types of shear, resulting in different conformational changes in these molecules. The consequences of such changes caused by variable shear energy are proposed to underlie formation of amyloid strains causing different amyloid diseases. Amyloid researchers are urged to undertake studies with amyloids, anti-amyloid drugs, and antibodies while all of these are under shear conditions similar to those in the brain.
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Affiliation(s)
- Conrad N Trumbore
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, USA
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8
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Liao Q, Owen MC, Bali S, Barz B, Strodel B. Aβ under stress: the effects of acidosis, Cu 2+-binding, and oxidation on amyloid β-peptide dimers. Chem Commun (Camb) 2018; 54:7766-7769. [PMID: 29947363 DOI: 10.1039/c8cc02263a] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In light of the high affinity of Cu2+ for Alzheimer's Aβ1-42 and its ability to subsequently catalyze the formation of radicals, we examine the effects of Cu2+ binding, Aβ oxidation, and an acidic environment on the conformational dynamics of the smallest Aβ1-42 oligomer, the Aβ1-42 dimer. Transition networks calculated from Hamiltonian replica exchange molecular dynamics (H-REMD) simulations reveal that the decreased pH considerably increased the β-sheet content, whereas Cu2+ binding increased the exposed hydrophobic surface area, both of which can contribute to an increased oligomerization propensity and toxicity.
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Affiliation(s)
- Qinghua Liao
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany.
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9
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Eskici G, Axelsen PH. Mass Exchange and Equilibration Processes in AOT Reverse Micelles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:2522-2530. [PMID: 29364686 DOI: 10.1021/acs.langmuir.7b04192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Reverse micelles (RMs) made with sodium bis(2-ethylhexyl)sulfosuccinate suspended in isooctane are commonly used experimental models of aqueous microenvironments. However, there are important unanswered questions about the very characteristic that makes them of interest, namely their size. To explore the factors that determine the size of RMs, all-atom molecular dynamics simulations of RMs with different sizes but the same water-loading ratio were performed. An Anton 2 machine was used so that systems of the necessary size could be extended into the microsecond timescale, and mass exchange processes could be observed. Contrary to hypothesis, there were no net gains or losses of water by diffusion between RMs of different size. However, gains and losses did occur following fusion events. RM fusion followed RM contact only when waters were present among the hydrophobic surfactant chains at the point of contact. The presence of an encapsulated 40-residue amyloid beta peptide did not directly promote RM fusion, but it quickly and efficiently terminated each fusion event. Before fusion terminated, however, the size of the peptide-containing RM increased without a corresponding change in its water-loading ratio. We conclude that the mass transfer between RMs is most likely accomplished through transient fusion events, rather than through the diffusion of component molecules through the organic phase. The behavior of the amyloid beta peptide in this system underscores its propensity to embed in, and fold in response to, multiple interactions with the surfactant layer.
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Affiliation(s)
- Gozde Eskici
- Department of Biochemistry & Biophysics, University of Pennsylvania Perelman School of Medicine , Philadelphia 19104, United States
| | - Paul H Axelsen
- Departments of Pharmacology, Biochemistry and Biophysics, and Medicine, University of Pennsylvania , 1009C Stellar Chance Laboratories, 422 Curie Blvd, Philadelphia, Pennsylvania 19104-6059, United States
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10
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Lin YL, Cheng YS, Ho CI, Guo ZH, Huang SJ, Org ML, Oss A, Samoson A, Chan JCC. Preparation of fibril nuclei of beta-amyloid peptides in reverse micelles. Chem Commun (Camb) 2018; 54:10459-10462. [DOI: 10.1039/c8cc05882b] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Protofibrils of beta-amyloid peptides formed by fibril nuclei incubated in reverse micelles.
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Affiliation(s)
- Yen-Ling Lin
- Department of Chemistry, National Taiwan University
- Taipei
- Taiwan
| | - Yu-Sheng Cheng
- Department of Chemistry, National Taiwan University
- Taipei
- Taiwan
| | - Cheng-I Ho
- Department of Chemistry, National Taiwan University
- Taipei
- Taiwan
| | - Zhong-Hong Guo
- Department of Chemistry, National Taiwan University
- Taipei
- Taiwan
| | - Shing-Jong Huang
- Instrumentation Center
- National Taiwan University
- Taipei 10617
- Taiwan
| | - Mai-Liis Org
- Institute of Health Technologies, Tallinn University of Technology
- Tallinn
- Estonia
| | - Andres Oss
- Institute of Health Technologies, Tallinn University of Technology
- Tallinn
- Estonia
| | - Ago Samoson
- Institute of Health Technologies, Tallinn University of Technology
- Tallinn
- Estonia
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11
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Affiliation(s)
- Jancy Nixon Abraham
- Polymer Science and Engineering Division; CSIR National Chemical Laboratory; Pune India
| | - Corinne Nardin
- Université de Pau et des Pays de l'Adour (UPPA), Institut des sciences analytiques et de physico-chimie pour l'environnement et les matériaux (IPREM); Equipe Physique et Chimie des Polymères (EPCP); Pau France
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12
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Manna S, Panse CH, Sontakke VA, Sangamesh S, Srivatsan SG. Probing Human Telomeric DNA and RNA Topology and Ligand Binding in a Cellular Model by Using Responsive Fluorescent Nucleoside Probes. Chembiochem 2017; 18:1604-1615. [PMID: 28569423 PMCID: PMC5724660 DOI: 10.1002/cbic.201700283] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Indexed: 01/03/2023]
Abstract
The development of biophysical systems that enable an understanding of the structure and ligand-binding properties of G-quadruplex (GQ)-forming nucleic acid sequences in cells or models that mimic the cellular environment would be highly beneficial in advancing GQ-directed therapeutic strategies. Herein, the establishment of a biophysical platform to investigate the structure and recognition properties of human telomeric (H-Telo) DNA and RNA repeats in a cell-like confined environment by using conformation-sensitive fluorescent nucleoside probes and a widely used cellular model, bis(2-ethylhexyl) sodium sulfosuccinate reverse micelles (RMs), is described. The 2'-deoxy and ribonucleoside probes, composed of a 5-benzofuran uracil base analogue, faithfully report the aqueous micellar core through changes in their fluorescence properties. The nucleoside probes incorporated into different loops of H-Telo DNA and RNA oligonucleotide repeats are minimally perturbing and photophysically signal the formation of respective GQ structures in both aqueous buffer and RMs. Furthermore, these sensors enable a direct comparison of the binding affinity of a ligand to H-Telo DNA and RNA GQ structures in the bulk and confined environment of RMs. These results demonstrate that this combination of a GQ nucleoside probe and easy-to-handle RMs could provide new opportunities to study and devise screening-compatible assays in a cell-like environment to discover GQ binders of clinical potential.
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Affiliation(s)
- Sudeshna Manna
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
| | - Cornelia H. Panse
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
| | - Vyankat A. Sontakke
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
| | - Sarangamath Sangamesh
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
| | - Seergazhi G. Srivatsan
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
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13
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Kedia N, Almisry M, Bieschke J. Glucose directs amyloid-beta into membrane-active oligomers. Phys Chem Chem Phys 2017; 19:18036-18046. [PMID: 28671211 PMCID: PMC5654640 DOI: 10.1039/c7cp02849k] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oligomeric amyloid-β 1-42 (Aβ-42) peptides are considered to be the most toxic species connected to the occurrence of Alzheimer's disease. However, not all aggregation conditions promote oligomer formation in vitro, raising the question whether oligomer formation in vivo also requires a specific suitable cellular environment. We recently found that interaction with neuronal membranes initiates aggregation of Aβ-42 and neuronal uptake. Our data suggest that small molecules in the extracellular space can facilitate the formation of membrane-active Aβ-42 oligomers. We analyzed the early stage of Aβ-42 aggregation in the presence of glucose and sucrose and found that these sugars strongly favor Aβ-42 oligomer formation. We characterized oligomers by dynamic light scattering, atomic force microscopy, immuno-transmission electron microscopy and fluorescence cross correlation spectroscopy. We found that Aβ-42 spontaneously and rapidly forms low molecular weight oligomers in the presence of sugars. Slightly acidic pH (6.7-7) greatly favors oligomer formation when compared to the extracellular physiological pH (7.4). Circular dichroism demonstrated that these Aβ-42 oligomers did not adopt a β-sheet structure. Unstructured oligomeric Aβ-42 interacted with membrane bilayers of giant unilamellar vesicles (GUV) and neuronal model cells, facilitated cellular uptake of Aβ-42, and inhibition of mitochondrial activity. Our data therefore suggest that elevated concentrations of glucose within the range observed in diabetic individuals (10 mM) facilitate the formation of membrane-active Aβ-42 oligomers.
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Affiliation(s)
- Niraja Kedia
- Department of Biomedical Engineering, Washington University, 63130 St. Louis, MO, USA.
| | - Michael Almisry
- Department of Biomedical Engineering, Washington University, 63130 St. Louis, MO, USA.
| | - Jan Bieschke
- Department of Biomedical Engineering, Washington University, 63130 St. Louis, MO, USA.
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14
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Abstract
Previously published experimental studies have suggested that when the 40-residue amyloid beta peptide is encapsulated in a reverse micelle, it folds into a structure that may nucleate amyloid fibril formation (Yeung, P. S.-W.; Axelsen, P. H. J. Am. Chem. Soc. 2012, 134, 6061 ). The factors that induce the formation of this structure have now been identified in a multi-microsecond simulation of the same reverse micelle system that was studied experimentally. Key features of the polypeptide-micelle interaction include the anchoring of a hydrophobic residue cluster into gaps in the reverse micelle surface, the formation of a beta turn at the anchor point that brings N- and C-terminal segments of the polypeptide into proximity, high ionic strength that promotes intramolecular hydrogen bond formation, and deformation of the reverse micelle surface to facilitate interactions with the surface along the entire length of the polypeptide. Together, these features cause the simulation-derived vibrational spectrum to red shift in a manner that reproduces the red-shift previously reported experimentally. On the basis of these findings, a new mechanism is proposed whereby membranes nucleate fibril formation and facilitate the in-register alignment of polypeptide strands that is characteristic of amyloid fibrils.
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Affiliation(s)
- Gözde Eskici
- Department of Biochemistry & Biophysics, 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 , Philadelphia, Pennsylvania 19104, United States
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15
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Fuglestad B, Gupta K, Wand AJ, Sharp KA. Characterization of Cetyltrimethylammonium Bromide/Hexanol Reverse Micelles by Experimentally Benchmarked Molecular Dynamics Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:1674-1684. [PMID: 26840651 DOI: 10.1021/acs.langmuir.5b03981] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Encapsulation of small molecules, proteins, and other macromolecules within the protective water core of reverse micelles is emerging as a powerful strategy for a variety of applications. The cationic surfactant cetyltrimethylammonium bromide (CTAB) in combination with hexanol as a cosurfactant is particularly useful in the context of solution NMR spectroscopy of encapsulated proteins. Small-angle X-ray and neutron scattering is employed to investigate the internal structure of the CTAB/hexanol reverse micelle particle under conditions appropriate for high-resolution NMR spectroscopy. The scattering profiles are used to benchmark extensive molecular dynamics simulations of this reverse micelle system and indicate that the parameters used in these simulations recapitulate experimental results. Scattering profiles and simulations indicate formation of homogeneous solutions of small approximately spherical reverse micelle particles at a water loading of 20 composed of ∼150 CTAB and 240 hexanol molecules. The 3000 waters comprising the reverse micelle core show a gradient of translational diffusion that reaches that of bulk water at the center. Rotational diffusion is slowed relative to bulk throughout the water core, with the greatest slowing near the CTAB headgroups. The 5 Å thick interfacial region of the micelle consists of overlapping layers of Br(-) enriched water, CTAB headgroups, and hexanol hydroxyl groups, containing about one-third of the total water. This study employs well-parametrized MD simulations, X-ray and neutron scattering, and electrostatic theory to illuminate fundamental properties of CTAB/hexanol reverse micelle size, shape, partitioning, and water behavior.
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Affiliation(s)
- Brian Fuglestad
- Johnson Research Foundation and Department of Biochemistry & Biophysics, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania 19104-6059, United States
| | - Kushol Gupta
- Johnson Research Foundation and Department of Biochemistry & Biophysics, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania 19104-6059, United States
| | - A Joshua Wand
- Johnson Research Foundation and Department of Biochemistry & Biophysics, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania 19104-6059, United States
| | - Kim A Sharp
- Johnson Research Foundation and Department of Biochemistry & Biophysics, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania 19104-6059, United States
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16
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Hu YX, Ying YL, Gu Z, Cao C, Yan BY, Wang HF, Long YT. Single molecule study of initial structural features on the amyloidosis process. Chem Commun (Camb) 2016; 52:5542-5. [DOI: 10.1039/c6cc01292b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We employed an α-hemolysin (α-HL) nanopore as a single-molecule tool to investigate the effects of initial structure on the amyloidosis process.
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Affiliation(s)
- Yong-Xu Hu
- Key Laboratory for Advanced Materials & Department of Chemistry
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
| | - Yi-Lun Ying
- Key Laboratory for Advanced Materials & Department of Chemistry
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
| | - Zhen Gu
- Key Laboratory for Advanced Materials & Department of Chemistry
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
| | - Chan Cao
- Key Laboratory for Advanced Materials & Department of Chemistry
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
| | - Bing-Yong Yan
- School of Information Science and Engineering
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
| | - Hui-Feng Wang
- School of Information Science and Engineering
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
| | - Yi-Tao Long
- Key Laboratory for Advanced Materials & Department of Chemistry
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
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17
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Li M, Zhao C, Ren J, Qu X. Chiral Metallo-Supramolecular Complex Directed Enantioselective Self-Assembly of β-Sheet Breaker Peptide for Amyloid Inhibition. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:4651-4655. [PMID: 26136296 DOI: 10.1002/smll.201501329] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 05/29/2015] [Indexed: 06/04/2023]
Abstract
Chiral recognition plays an important role for biomacromolecules involved self-assembly and further affects their biological functions. Herein, it is demonstrated that two chiral metal complexes can enantioselectively bind with Aβ15-20, leading to the formation of different self-assembled nanostructures. With the ability of both metal complexes and Aβ15-20 to inhibit Aβ1-40 aggregation, the NiM@P hybrid particles can act as bifunctional Aβ inhibitors.
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Affiliation(s)
- Meng Li
- Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
| | - Chuanqi Zhao
- Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
| | - Jinsong Ren
- Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
| | - Xiaogang Qu
- Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
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18
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Breydo L, Sales AE, Frege T, Howell MC, Zaslavsky BY, Uversky VN. Effects of Polymer Hydrophobicity on Protein Structure and Aggregation Kinetics in Crowded Milieu. Biochemistry 2015; 54:2957-66. [PMID: 25919930 DOI: 10.1021/acs.biochem.5b00116] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We examined the effects of water-soluble polymers of various degrees of hydrophobicity on the folding and aggregation of proteins. The polymers we chose were polyethylene glycol (PEG) and UCON (1:1 copolymer of ethylene glycol and propylene glycol). The presence of additional methyl groups in UCON makes it more hydrophobic than PEG. Our earlier analysis revealed that similarly sized PEG and UCON produced different changes in the solvent properties of water in their solutions and induced morphologically different α-synuclein aggregates [Ferreira, L. A., et al. (2015) Role of solvent properties of aqueous media in macromolecular crowding effects. J. Biomol. Struct. Dyn., in press]. To improve our understanding of molecular mechanisms defining behavior of proteins in a crowded environment, we tested the effects of these polymers on secondary and tertiary structure and aromatic residue solvent accessibility of 10 proteins [five folded proteins, two hybrid proteins; i.e., protein containing ordered and disordered domains, and three intrinsically disordered proteins (IDPs)] and on the aggregation kinetics of insulin and α-synuclein. We found that effects of both polymers on secondary and tertiary structures of folded and hybrid proteins were rather limited with slight unfolding observed in some cases. Solvent accessibility of aromatic residues was significantly increased for the majority of the studied proteins in the presence of UCON but not PEG. PEG also accelerated the aggregation of protein into amyloid fibrils, whereas UCON promoted aggregation to amyloid oligomers instead. These results indicate that even a relatively small change in polymer structure leads to a significant change in the effect of this polymer on protein folding and aggregation. This is an indication that protein folding and especially aggregation are highly sensitive to the presence of other macromolecules, and an excluded volume effect is insufficient to describe their effect.
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19
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Hilaire MR, Abaskharon RM, Gai F. Biomolecular Crowding Arising from Small Molecules, Molecular Constraints, Surface Packing, and Nano-Confinement. J Phys Chem Lett 2015; 6:2546-53. [PMID: 26266732 PMCID: PMC4610718 DOI: 10.1021/acs.jpclett.5b00957] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The effect of macromolecular crowding on the structure, dynamics, and reactivity of biomolecules is well established and the relevant research has been extensively reviewed. Herein, we focus our discussion on crowding effects arising from small cosolvent molecules and densely packed surface conditions. In addition, we highlight recent efforts that capitalize on the excluded volume effect for various tailored biochemical and biophysical applications. Specifically, we discuss how a targeted increase in local mass density can be exploited to gain insight into the folding dynamics of the protein of interest and how confinement via reverse micelles can be used to study a range of biophysical questions, from protein hydration dynamics to amyloid formation.
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Affiliation(s)
| | | | - Feng Gai
- To whom correspondence should be addressed; ; Phone: 215-573-6256; Fax: 215-573-2112
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20
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The crowd you're in with: Effects of different types of crowding agents on protein aggregation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:346-57. [DOI: 10.1016/j.bbapap.2013.11.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 11/01/2013] [Accepted: 11/11/2013] [Indexed: 11/21/2022]
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21
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Sathish V, Ramdass A, Lu ZZ, Velayudham M, Thanasekaran P, Lu KL, Rajagopal S. Aggregation-Induced Emission Enhancement in Alkoxy-Bridged Binuclear Rhenium(I) Complexes: Application as Sensor for Explosives and Interaction with Microheterogeneous Media. J Phys Chem B 2013; 117:14358-66. [DOI: 10.1021/jp407939j] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Veerasamy Sathish
- School
of Chemistry, Madurai Kamaraj University, Madurai 625 021, India
| | - Arumugam Ramdass
- School
of Chemistry, Madurai Kamaraj University, Madurai 625 021, India
| | - Zong-Zhan Lu
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
| | | | | | - Kuang-Lieh Lu
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
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22
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Ma Q, Hu JY, Chen J, Liang Y. The role of crowded physiological environments in prion and prion-like protein aggregation. Int J Mol Sci 2013; 14:21339-52. [PMID: 24284393 PMCID: PMC3856008 DOI: 10.3390/ijms141121339] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 09/24/2013] [Accepted: 09/27/2013] [Indexed: 01/07/2023] Open
Abstract
Prion diseases and prion- like protein misfolding diseases are related to the accumulation of abnormal aggregates of the normal host proteins including prion proteins and Tau protein. These proteins possess self-templating and transmissible characteristics. The crowded physiological environments where the aggregation of these amyloidogenic proteins takes place can be imitated in vitro by the addition of macromolecular crowding agents such as inert polysaccharides. In this review, we summarize the aggregation of prion proteins in crowded physiological environments and discuss the role of macromolecular crowding in prion protein aggregation. We also summarize the aggregation of prion- like proteins including human Tau protein, human α-synuclein, and human copper, zinc superoxide dismutase under macromolecular crowding environments and discuss the role of macromolecular crowding in prion- like protein aggregation. The excluded-volume effects caused by macromolecular crowding could accelerate the aggregation of neurodegenerative disease-associated proteins while inhibiting the aggregation of the proteins that are not neurodegenerative disease-associated.
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Affiliation(s)
- Qian Ma
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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23
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Saha R, Rakshit S, Verma PK, Mitra RK, Pal SK. Protein-cofactor binding and ultrafast electron transfer in riboflavin binding protein under the spatial confinement of nanoscopic reverse micelles. J Mol Recognit 2013; 26:59-66. [DOI: 10.1002/jmr.2246] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/09/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Ranajay Saha
- Department of Chemical, Biological and Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences; Block JD, Sector III Salt Lake; Kolkata 700098; India
| | - Surajit Rakshit
- Department of Chemical, Biological and Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences; Block JD, Sector III Salt Lake; Kolkata 700098; India
| | - Pramod Kumar Verma
- Department of Chemical, Biological and Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences; Block JD, Sector III Salt Lake; Kolkata 700098; India
| | - Rajib Kumar Mitra
- Department of Chemical, Biological and Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences; Block JD, Sector III Salt Lake; Kolkata 700098; India
| | - Samir Kumar Pal
- Department of Chemical, Biological and Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences; Block JD, Sector III Salt Lake; Kolkata 700098; India
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24
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Guo Y, Wang J. Spectroscopic evidence for polymorphic aggregates formed by amyloid-β fragments. Chemphyschem 2012; 13:3901-8. [PMID: 23112008 DOI: 10.1002/cphc.201200611] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 09/30/2012] [Indexed: 12/26/2022]
Abstract
Understanding the structure of amyloid-β (Aβ) aggregates is a key step towards elucidating the pathology of Alzheimer's disease. In this work, three fragments of the Aβ(1-42) protein, Aβ(1-25) (DAEFRHDSGYEVHHQKLVFFAEDVG), Aβ(25-35) (GSNKGAIIGLM), and Aβ(33-42) (GLMVGGVVIA), were synthesized, and their aggregated structures were examined by linear infrared spectroscopy in the amide-I (mainly the C=O stretching) region. The structures of the formed aggregates were found to be both sequence and pH dependent. The results suggest that instead of forming matured fibrils, as in the case of full-length Aβ(1-42), both Aβ(1-25) and Aβ(33-42) form a mixture of threadlike β-sheet fibril, soluble β-sheet oligomer, and random coil structures. The β-sheet conformations were found to be mainly antiparallel for the former and both parallel and antiparallel for the latter. However, the Aβ(25-35) fragment was found to form assembled fibrils containing predominantly parallel β-sheets. The conformation and morphology of the aggregates were also confirmed by circular dichroism measurements and transmission electron microscopy. Factors influencing the structures of the aggregates formed by the Aβ fragments were discussed.
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Affiliation(s)
- Yangmei Guo
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190 P R China
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25
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Xue Z, Zhang J, Peng L, Li J, Mu T, Han B, Yang G. Nanosized Poly(ethylene glycol) Domains within Reverse Micelles Formed in CO2. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201206197] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Xue Z, Zhang J, Peng L, Li J, Mu T, Han B, Yang G. Nanosized Poly(ethylene glycol) Domains within Reverse Micelles Formed in CO2. Angew Chem Int Ed Engl 2012; 51:12325-9. [DOI: 10.1002/anie.201206197] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Indexed: 11/06/2022]
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27
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Yeung PSW, Eskici G, Axelsen PH. Infrared spectroscopy of proteins in reverse micelles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:2314-8. [PMID: 23098833 DOI: 10.1016/j.bbamem.2012.10.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 10/14/2012] [Indexed: 11/28/2022]
Abstract
Reverse micelles are a versatile model system for the study of crowded microenvironments containing limited water, such as those found in various tissue spaces or endosomes. They also preclude protein aggregation. Reverse micelles are amenable to study by linear and nonlinear infrared spectroscopies, which have demonstrated that the encapsulation of polypeptides and enzymatically active proteins into reverse micelles leads to conformational changes not seen in bulk solution. The potential value of this model system for understanding the folding and kinetic behavior of polypeptides and proteins in biologically important circumstances warrants increased study of reverse micelle systems by infrared spectroscopy. This article is part of a Special Issue entitled: FTIR in membrane proteins and peptide studies.
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Affiliation(s)
- Priscilla S-W Yeung
- Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104, USA
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28
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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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