151
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Chaudhary N, Nagaraj R. Impact on the replacement of Phe by Trp in a short fragment of Aβ amyloid peptide on the formation of fibrils. J Pept Sci 2010; 17:115-23. [PMID: 21234983 DOI: 10.1002/psc.1339] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/01/2010] [Accepted: 11/07/2010] [Indexed: 11/11/2022]
Abstract
Aβ(16-22) (Ac-KLVFFAE-NH(2) ) is one of the shortest amyloid fibril-forming sequences identified in β-amyloid peptide. At neutral pH, the peptide forms fibrils in the concentration range of 0.2-2.0 mM after ≥ 10 days of incubation. Structures of the fibrils proposed based on solid-state NMR and MD simulations studies suggest antiparallel arrangement of β-strands and aromatic interactions between the Phe residues. In an effort to examine the role of aromatic interactions between two Phe residues in Aβ(16-22) , we have studied the self-assembly of Aβ(16-22) (AβFF) and two of its variants, Ac-KLVFWAE-NH(2) (AβFW) and Ac-KLVWFAE-NH(2) (AβWF). The peptides were dissolved in methanol (MeOH) at a concentration of 1 mM and in water (AβFW and AβWF, 1 mM; AβFF, 330 µM). Peptide solutions (100 µM) were prepared in 50 mM sodium phosphate buffer at pH 7 by diluting from MeOH and water stock solutions. AβFW forms amyloid-like fibrils immediately from MeOH, as indicated by atomic force microscopy. Dilution of AβFW into phosphate buffer from stock solution prepared in MeOH results in fibrils, but with different morphology and dimensions. The secondary structure potentiated by MeOH seems to be important for the self-assembly of AβFW, as fibrils are not formed from water where the peptide is unordered. On the other hand, AβFF and AβWF do not form amyloid fibrils rapidly from any of the solvents used for dissolution. However, drying of AβWF from MeOH on mica surface gives rod-like and fibrous structures. Our study indicates that positioning of the aromatic residues F and W has an important role to play in promoting self-assembly of the Aβ(16-22) peptides.
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Affiliation(s)
- Nitin Chaudhary
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500 007, India
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152
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Fox A, Snollaerts T, Errecart Casanova C, Calciano A, Nogaj LA, Moffet DA. Selection for nonamyloidogenic mutants of islet amyloid polypeptide (IAPP) identifies an extended region for amyloidogenicity. Biochemistry 2010; 49:7783-9. [PMID: 20698575 DOI: 10.1021/bi100337p] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The aggregation of the 37-residue protein, islet amyloid polypeptide (IAPP), as either insoluble amyloid or as small oligomers, appears to play a direct role in the death of pancreatic beta-islet cells in type II diabetes. While IAPP has been known to be the primary component of type II diabetes amyloid, the molecular interactions responsible for this aggregation have not been identified. To identify the aggregation-prone region(s), we constructed a library of randomly generated point mutants of IAPP. This mutant IAPP library was expressed in Escherichia coli as genetic fusions to the reporter protein enhanced green fluorescent protein (EGFP). Because IAPP aggregates rapidly, both independently and when fused to EGFP, the fusion protein does not yield a functional, fluorescent EGFP. However, mutations of IAPP that result in nonamyloidogenic sequences remain soluble and allow EGFP to fold and fluoresce. Using this screen, we identified 22 single mutations, 4 double mutations, and 2 triple mutations of IAPP that appear to be less amyloidogenic than wild-type human IAPP. A comparison of these sequences suggests residues 13 and 15-17 comprise an additional aggregation-prone region outside of the main amyloidogenic region of IAPP.
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Affiliation(s)
- Ayano Fox
- Department of Chemistry and Biochemistry, Loyola Marymount University, 1 LMU Drive, Los Angeles, California 90045, USA
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153
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Zhao JH, Liu HL, Chuang CK, Liu KT, Tsai WB, Ho Y. Molecular dynamics simulations to investigate the stability and aggregation behaviour of the amyloid-forming peptide VQIVYK from tau protein. MOLECULAR SIMULATION 2010. [DOI: 10.1080/08927022.2010.499147] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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154
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Bett CK, Serem WK, Fontenot KR, Hammer RP, Garno JC. Effects of peptides derived from terminal modifications of the aβ central hydrophobic core on aβ fibrillization. ACS Chem Neurosci 2010; 1:661-78. [PMID: 22778807 DOI: 10.1021/cn900019r] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 08/05/2010] [Indexed: 01/06/2023] Open
Abstract
Considerable research effort has focused on the discovery of mitigators that block the toxicity of the β-amyloid peptide (Aβ) by targeting a specific step involved in Aβ fibrillogenesis and subsequent aggregation. Given that aggregation intermediates are hypothesized to be responsible for Aβ toxicity, such compounds could likely prevent or mitigate aggregation, or alternatively cause further association of toxic oligomers into larger nontoxic aggregates. Herein we investigate the effect of modifications of the KLVFF hydrophobic core of Aβ by replacing N- and C-terminal groups with various polar moieties. Several of these terminal modifications were found to disrupt the formation of amyloid fibrils and in some cases induced the disassembly of preformed fibrils. Significantly, mitigators that incorporate MiniPEG polar groups were found to be effective against Aβ(1-40) fibrilligonesis. Previously, we have shown that mitigators incorporating alpha,alpha-disubstituted amino acids (ααAAs) were effective in disrupting fibril formation as well as inducing fibril disassembly. In this work, we further disclose that the number of polar residues (six) and ααAAs (three) in the original mitigator can be reduced without dramatically changing the ability to disrupt Aβ(1-40) fibrillization in vitro.
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Affiliation(s)
- Cyrus K. Bett
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Wilson K. Serem
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Krystal R. Fontenot
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Robert P. Hammer
- New England Peptide LLC, 65 Zub Lane, Gardner, Massachusetts 01440
| | - Jayne C. Garno
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
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155
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Bett CK, Ngunjiri JN, Serem WK, Fontenot KR, Hammer RP, McCarley RL, Garno JC. Structure-activity relationships in peptide modulators of β-amyloid protein aggregation: variation in α,α-disubstitution results in altered aggregate size and morphology. ACS Chem Neurosci 2010; 1:608-26. [PMID: 22778850 DOI: 10.1021/cn100045q] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 06/25/2010] [Indexed: 12/20/2022] Open
Abstract
Neuronal cytotoxicity observed in Alzheimer's disease (AD) is linked to the aggregation of β-amyloid peptide (Aβ) into toxic forms. Increasing evidence points to oligomeric materials as the neurotoxic species, not Aβ fibrils; disruption or inhibition of Aβ self-assembly into oligomeric or fibrillar forms remains a viable therapeutic strategy to reduce Aβ neurotoxicity. We describe the synthesis and characterization of amyloid aggregation mitigating peptides (AAMPs) whose structure is based on the Aβ "hydrophobic core" Aβ(17-20), with α,α-disubstituted amino acids (ααAAs) added into this core as potential disrupting agents of fibril self-assembly. The number, positional distribution, and side-chain functionality of ααAAs incorporated into the AAMP sequence were found to influence the resultant aggregate morphology as indicated by ex situ experiments using atomic force microscopy (AFM) and transmission electron microscopy (TEM). For instance, AAMP-5, incorporating a sterically hindered ααAA with a diisobutyl side chain in the core sequence, disrupted Aβ(1-40) fibril formation. However, AAMP-6, with a less sterically hindered ααAA with a dipropyl side chain, altered fibril morphology, producing shorter and larger sized fibrils (compared with those of Aβ(1-40)). Remarkably, ααAA-AAMPs caused disassembly of existing Aβ fibrils to produce either spherical aggregates or protofibrillar structures, suggesting the existence of equilibrium between fibrils and prefibrillar structures.
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Affiliation(s)
- Cyrus K. Bett
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Johnpeter N. Ngunjiri
- NanoInk, Inc., Illinois Science & Technology Park, 8025 Lamon Ave, Skokie, Illinois 60077
| | - Wilson K. Serem
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Krystal R. Fontenot
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Robert P. Hammer
- New England Peptide LLC, 65 Zub Lane, Gardner, Massachusetts 01440
| | - Robin L. McCarley
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Jayne C. Garno
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
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156
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Schreml S, Kaiser E, Landthaler M, Szeimies RM, Babilas P. Amyloid in skin and brain: What′s the link? Exp Dermatol 2010; 19:953-7. [DOI: 10.1111/j.1600-0625.2010.01166.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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157
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Castelletto V, McKendrick JE, Hamley IW, Olsson U, Cenker C. PEGylated amyloid peptide nanocontainer delivery and release system. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:11624-11627. [PMID: 20666427 DOI: 10.1021/la101806z] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A micellar nanocontainer delivery and release system is designed on the basis of a peptide-polymer conjugate. The hybrid molecules self-assemble into micelles comprising a modified amyloid peptide core surrounded by a PEG corona. The modified amyloid peptide previously studied in our group forms helical ribbons based on a beta-sheet motif and contains beta-amino acids that are excluded from the beta-sheet structure, thus being potentially useful as fibrillization inhibitors. In the model peptide-PEG hybrid system studied, enzymatic degradation using alpha-chymotrypsin leads to selective cleavage close to the PEG-peptide linkage, break up of the micelles, and release of peptides in unassociated form. The release of monomeric peptide is useful because aggregation of the released peptide into beta-sheet amyloid fibrils is not observed. This concept has considerable potential in the targeted delivery of peptides for therapeutic applications.
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Affiliation(s)
- V Castelletto
- Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK
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158
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Shtainfeld A, Sheynis T, Jelinek R. Specific Mutations Alter Fibrillation Kinetics, Fiber Morphologies, and Membrane Interactions of Pentapeptides Derived from Human Calcitonin. Biochemistry 2010; 49:5299-307. [DOI: 10.1021/bi1002713] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Amit Shtainfeld
- Department of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Tania Sheynis
- Department of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Raz Jelinek
- Department of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
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159
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Molecular mechanism of Thioflavin-T binding to amyloid fibrils. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:1405-12. [PMID: 20399286 DOI: 10.1016/j.bbapap.2010.04.001] [Citation(s) in RCA: 1384] [Impact Index Per Article: 98.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 04/01/2010] [Accepted: 04/07/2010] [Indexed: 11/22/2022]
Abstract
Intense efforts to detect, diagnose, and analyze the kinetic and structural properties of amyloid fibrils have generated a powerful toolkit of amyloid-specific molecular probes. Since its first description in 1959, the fluorescent dye Thioflavin-T (ThT) has become among the most widely used "gold standards" for selectively staining and identifying amyloid fibrils both in vivo and in vitro. The large enhancement of its fluorescence emission upon binding to fibrils makes ThT a particularly powerful and convenient tool. Despite its widespread use in clinical and basic science applications, the molecular mechanism for the ability of ThT to recognize diverse types of amyloid fibrils and for the dye's characteristic fluorescence has only begun to be elucidated. Here, we review recent progress in the understanding of ThT-fibril interactions at an atomic resolution. These studies have yielded important insights into amyloid structures and the processes of fibril formation, and they also offer guidance for designing the next generation of amyloid assembly diagnostics, inhibitors, and therapeutics.
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160
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Rodrigues JR, Simões CJV, Silva CG, Brito RMM. Potentially amyloidogenic conformational intermediates populate the unfolding landscape of transthyretin: insights from molecular dynamics simulations. Protein Sci 2010; 19:202-19. [PMID: 19937650 DOI: 10.1002/pro.289] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Protein aggregation into insoluble fibrillar structures known as amyloid characterizes several neurodegenerative diseases, including Alzheimer's, Huntington's and Creutzfeldt-Jakob. Transthyretin (TTR), a homotetrameric plasma protein, is known to be the causative agent of amyloid pathologies such as FAP (familial amyloid polyneuropathy), FAC (familial amyloid cardiomiopathy) and SSA (senile systemic amyloidosis). It is generally accepted that TTR tetramer dissociation and monomer partial unfolding precedes amyloid fibril formation. To explore the TTR unfolding landscape and to identify potential intermediate conformations with high tendency for amyloid formation, we have performed molecular dynamics unfolding simulations of WT-TTR and L55P-TTR, a highly amyloidogenic TTR variant. Our simulations in explicit water allow the identification of events that clearly discriminate the unfolding behavior of WT and L55P-TTR. Analysis of the simulation trajectories show that (i) the L55P monomers unfold earlier and to a larger extent than the WT; (ii) the single alpha-helix in the TTR monomer completely unfolds in most of the L55P simulations while remain folded in WT simulations; (iii) L55P forms, early in the simulations, aggregation-prone conformations characterized by full displacement of strands C and D from the main beta-sandwich core of the monomer; (iv) L55P shows, late in the simulations, severe loss of the H-bond network and consequent destabilization of the CBEF beta-sheet of the beta-sandwich; (v) WT forms aggregation-compatible conformations only late in the simulations and upon extensive unfolding of the monomer. These results clearly show that, in comparison with WT, L55P-TTR does present a much higher probability of forming transient conformations compatible with aggregation and amyloid formation.
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Affiliation(s)
- J Rui Rodrigues
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
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161
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Abstract
Numerous short peptides have been shown to form beta-sheet amyloid aggregates in vitro. Proteins that contain such sequences are likely to be problematic for a cell, due to their potential to aggregate into toxic structures. We investigated the structures of 30 proteins containing 45 sequences known to form amyloid, to see how the proteins cope with the presence of these potentially toxic sequences, studying secondary structure, hydrogen-bonding, solvent accessible surface area and hydrophobicity. We identified two mechanisms by which proteins avoid aggregation: Firstly, amyloidogenic sequences are often found within helices, despite their inherent preference to form beta structure. Helices may offer a selective advantage, since in order to form amyloid the sequence will presumably have to first unfold and then refold into a beta structure. Secondly, amyloidogenic sequences that are found in beta structure are usually buried within the protein. Surface exposed amyloidogenic sequences are not tolerated in strands, presumably because they lead to protein aggregation via assembly of the amyloidogenic regions. The use of alpha-helices, where amyloidogenic sequences are forced into helix, despite their intrinsic preference for beta structure, is thus a widespread mechanism to avoid protein aggregation.
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Affiliation(s)
- Susan Tzotzos
- Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester M1 7DN, United Kingdom
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162
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Rubin N, Perugia E, Wolf SG, Klein E, Fridkin M, Addadi L. Relation between Serum Amyloid A Truncated Peptides and Their Suprastructure Chirality. J Am Chem Soc 2010; 132:4242-8. [DOI: 10.1021/ja909345p] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Noa Rubin
- Department of Structural Biology, Department of Organic Chemistry, and Irving and Cherna Moskowitz Center for Nano and Bio-Nano Imaging, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Emanuel Perugia
- Department of Structural Biology, Department of Organic Chemistry, and Irving and Cherna Moskowitz Center for Nano and Bio-Nano Imaging, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Sharon G. Wolf
- Department of Structural Biology, Department of Organic Chemistry, and Irving and Cherna Moskowitz Center for Nano and Bio-Nano Imaging, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Eugenia Klein
- Department of Structural Biology, Department of Organic Chemistry, and Irving and Cherna Moskowitz Center for Nano and Bio-Nano Imaging, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Mati Fridkin
- Department of Structural Biology, Department of Organic Chemistry, and Irving and Cherna Moskowitz Center for Nano and Bio-Nano Imaging, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Lia Addadi
- Department of Structural Biology, Department of Organic Chemistry, and Irving and Cherna Moskowitz Center for Nano and Bio-Nano Imaging, Weizmann Institute of Science, Rehovot, Israel 76100
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163
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Interaction of (benzylidene-hydrazono)-1,4-dihydropyridines with β-amyloid, acetylcholine, and butyrylcholine esterases. Bioorg Med Chem 2010; 18:2049-59. [DOI: 10.1016/j.bmc.2010.01.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Revised: 12/22/2009] [Accepted: 01/02/2010] [Indexed: 02/06/2023]
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164
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Kim J, Han TH, Kim YI, Park JS, Choi J, Churchill DG, Kim SO, Ihee H. Role of water in directing diphenylalanine assembly into nanotubes and nanowires. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2010; 22:583-7. [PMID: 20217753 DOI: 10.1002/adma.200901973] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- Jangbae Kim
- Center for Time-Resolved Diffraction, Department of Chemistry, Graduate School of Nanoscience & Technology (WCU), KAIST, 335 Gwahangno, Yuseong-gu, Daejeon, Republic of Korea
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165
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Barman AK, Verma S. Sunlight mediated disruption of peptide-based soft structures decorated with gold nanoparticles. Chem Commun (Camb) 2010; 46:6992-4. [DOI: 10.1039/c0cc02604b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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166
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Su Y, Yan X, Wang A, Fei J, Cui Y, He Q, Li J. A peony-flower-like hierarchical mesocrystal formed by diphenylalanine. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm00110d] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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167
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Todorova N, Hung A, Maaser SM, Griffin MDW, Karas J, Howlett GJ, Yarovsky I. Effects of mutation on the amyloidogenic propensity of apolipoprotein C-II60–70 peptide. Phys Chem Chem Phys 2010; 12:14762-74. [DOI: 10.1039/c0cp00299b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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168
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Wu C, Biancalana M, Koide S, Shea JE. Binding Modes of Thioflavin-T to the Single-Layer β-Sheet of the Peptide Self-Assembly Mimics. J Mol Biol 2009; 394:627-33. [DOI: 10.1016/j.jmb.2009.09.056] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 09/18/2009] [Accepted: 09/23/2009] [Indexed: 10/20/2022]
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169
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Abstract
The highly toxic A beta (25-35) is a peculiar peptide that differs from all the other commonly studied beta-amyloid peptides because of its extremely rapid aggregation properties and enhanced neurotoxicity. We investigated A beta (25-35) aggregation in H2O at pH 3.0 and at pH 7.4 by means of in-solution analyses. Adopting UV spectroscopy, Congo red spectrophotometry and thioflavin T fluorimetry, we were able to quantify, in water, the very fast assembling time necessary for A beta (25-35) to form stable insoluble aggregates and their ability to seed or not seed fibril growth. Our quantitative results, which confirm a very rapid assembly leading to stable insoluble aggregates of A beta (25-35) only when incubated at pH 7.4, might be helpful for designing novel aggregation inhibitors and to shed light on the in vivo environment in which fibril formation takes place.
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170
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Hudson SA, Ecroyd H, Kee TW, Carver JA. The thioflavin T fluorescence assay for amyloid fibril detection can be biased by the presence of exogenous compounds. FEBS J 2009; 276:5960-72. [PMID: 19754881 DOI: 10.1111/j.1742-4658.2009.07307.x] [Citation(s) in RCA: 433] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Thioflavin T (ThT) dye fluorescence is used regularly to quantify the formation and inhibition of amyloid fibrils in the presence of anti-amyloidogenic compounds such as polyphenols. However, in this study, it was shown, using three polyphenolics (curcumin, quercetin and resveratrol), that ThT fluorescence should be used with caution in the presence of such exogenous compounds. The strong absorptive and fluorescent properties of quercetin and curcumin were found to significantly bias the ThT fluorescence readings in both in situ real-time ThT assays and single time-point dilution ThT-type assays. The presence of curcumin at concentrations as low as 0.01 and 1 mum was sufficient to interfere with the ThT fluorescence associated with fibrillar amyloid-beta(1-42) (0.5 mum) and fibrillar reduced and carboxymethylated kappa-casein (50 mum), respectively. The ThT fluorescence associated with fibrillar amyloid-beta(1-42) was also biased using higher concentrations of resveratrol, a polyphenol that is not spectroscopically active at the wavelengths of ThT fluorescence, implying that there can be direct interactions between ThT and the exogenous compound and/or competitive binding with ThT for the fibrils. Thus, in all cases where ThT is used in the presence of an exogenous compound, biases for amyloid-associated ThT fluorescence should be tested, regardless of whether the additive is spectroscopically active. Simple methods to conduct these tests were described. The Congo red spectral shift assay is demonstrated as a more viable spectrophotometric alternative to ThT, but allied methods, such as transmission electron microscopy, should also be used to assess fibril formation independently of dye-based assays. Structured digital abstract: * MINT-7259867: RCMkappa-CN (uniprotkb:P02668) and RCMkappa-CN (uniprotkb:P02668) bind (MI:0407) by electron microscopy (MI:0040) * MINT-7258930: RCMkappa-CN (uniprotkb:P02668) and RCMkappa-CN (uniprotkb:P02668) bind (MI:0407) by fluorescence technologies (MI:0051) * MINT-7259878: Amyloid beta (uniprotkb:P05067) and Amyloid beta (uniprotkb:P05067) bind (MI:0407) by fluorescence technologies (MI:0051).
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Affiliation(s)
- Sean A Hudson
- School of Chemistry & Physics, The University of Adelaide, Australia
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171
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Tamamis P, Adler-Abramovich L, Reches M, Marshall K, Sikorski P, Serpell L, Gazit E, Archontis G. Self-assembly of phenylalanine oligopeptides: insights from experiments and simulations. Biophys J 2009; 96:5020-9. [PMID: 19527662 DOI: 10.1016/j.bpj.2009.03.026] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 02/25/2009] [Accepted: 03/24/2009] [Indexed: 10/20/2022] Open
Abstract
Studies of peptide-based nanostructures provide general insights into biomolecular self-assembly and can lead material engineering toward technological applications. The diphenylalanine peptide (FF) self-assembles into discrete, hollow, well ordered nanotubes, and its derivatives form nanoassemblies of various morphologies. Here we demonstrate for the first time, to our knowledge, the formation of planar nanostructures with beta-sheet content by the triphenylalanine peptide (FFF). We characterize these structures using various microscopy and spectroscopy techniques. We also obtain insights into the interactions and structural properties of the FF and FFF nanostructures by 0.4-micros, implicit-solvent, replica-exchange, molecular-dynamics simulations of aqueous FF and FFF solutions. In the simulations the peptides form aggregates, which often contain open or ring-like peptide networks, as well as elementary and network-containing structures with beta-sheet characteristics. The networks are stabilized by polar and nonpolar interactions, and by the surrounding aggregate. In particular, the charged termini of neighbor peptides are involved in hydrogen-bonding interactions and their aromatic side chains form "T-shaped" contacts, as in three-dimensional FF crystals. These interactions may assist the FF and FFF self-assembly at the early stage, and may also stabilize the mature nanostructures. The FFF peptides have higher network propensities and increased aggregate stabilities with respect to FF, which can be interpreted energetically.
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172
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Huang CW, Tseng CC, Chen YH, Chen YH, Chou WY, Lee HJ. Substitution of residues at the double dimer interface affects the stability and oligomerization of goose delta-crystallin. FEBS J 2009; 276:5126-36. [PMID: 19674108 DOI: 10.1111/j.1742-4658.2009.07209.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Delta-crystallin is the major structural protein in avian and reptilian eye lenses, and confers special refractive properties. The protein is a homotetramer arranged as a dimer of dimers. In the present study, the roles of the side chains of Glu267, Lys315, and Glu327, which provide hydrogen bonds at the double dimer interface, were investigated. Hydrophobic side chain substitution led to all mutant proteins having an unstable dimer interface. The E267L/E327L mutant had the greatest sensitivity to temperature, urea and guanidinium hydrochloride denaturation, and the most extensive exposure of hydrophobic patches, as judged by 1-anilinonaphthalene-8-sulfonic acid fluorescence, CD, and tryptophan fluorescence. In contrast, the E267L/K315L/E327L mutant showed higher stability than the E267L/E327L mutant. Some level of the dissociated dimeric form was observed in the K315L mutant, but it was not observed for the K315A and E267L/K315L mutants. The E327L mutant was partially in the dissociated dimeric form, whereas the E267/E327L mutant was predominantly dissociated into dimers. In contrast, the triple mutant of E267L/K315L/E327L retained a tetrameric structure. In the presence of urea, a stable monomeric intermediate with higher stability than the wild type was identified for the K315A mutant. Disruption of interfacial interactions at Glu267 led to polymerization of partly unfolded intermediates in the presence of 3 m urea. However, these polymeric forms were not observed with combinations of the E267L mutation with other mutations. These results indicate that these hydrogen bonds, which are present at different contact surfaces in the dimer-dimer interface, perform distinct functions in double dimer assembly. The coordination of these interactions is critical for the stability and tetramer formation of delta-crystallin.
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Affiliation(s)
- Chih-Wei Huang
- Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan
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173
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Hudson SA, Ecroyd H, Dehle FC, Musgrave IF, Carver JA. (-)-epigallocatechin-3-gallate (EGCG) maintains kappa-casein in its pre-fibrillar state without redirecting its aggregation pathway. J Mol Biol 2009; 392:689-700. [PMID: 19616561 DOI: 10.1016/j.jmb.2009.07.031] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Revised: 07/07/2009] [Accepted: 07/09/2009] [Indexed: 02/08/2023]
Abstract
The polyphenol (-)-epigallocatechin-3-gallate (EGCG) has recently attracted much research interest in the field of protein-misfolding diseases because of its potent anti-amyloid activity against amyloid-beta, alpha-synuclein and huntingtin, the amyloid-fibril-forming proteins involved in Alzheimer's, Parkinson's and Huntington's diseases, respectively. EGCG redirects the aggregation of these polypeptides to a disordered off-folding pathway that results in the formation of non-toxic amorphous aggregates. Whether this anti-fibril activity is specific to these disease-related target proteins or is more generic remains to be established. In addition, the mechanism by which EGCG exerts its effects, as with all anti-amyloidogenic polyphenols, remains unclear. To address these aspects, we have investigated the ability of EGCG to inhibit amyloidogenesis of the generic model fibril-forming protein RCMkappa-CN (reduced and carboxymethylated kappa-casein) and thereby protect pheochromocytoma-12 cells from RCMkappa-CN amyloid-induced toxicity. We found that EGCG potently inhibits in vitro fibril formation by RCMkappa-CN [the IC(50) for 50 microM RCMkappa-CN is 13+/-1 microM]. Biophysical studies reveal that EGCG prevents RCMkappa-CN fibril formation by stabilising RCMkappa-CN in its native-like state rather than by redirecting its aggregation to the disordered, amorphous aggregation pathway. Thus, while it appears that EGCG is a generic inhibitor of amyloid-fibril formation, the mechanism by which it achieves this inhibition is specific to the target fibril-forming polypeptide. It is proposed that EGCG is directed to the amyloidogenic sheet-turn-sheet motif of monomeric RCMkappa-CN with high affinity by strong non-specific hydrophobic associations. Additional non-covalent pi-pi stacking interactions between the polyphenolic and aromatic residues common to the amyloidogenic sequence are also implicated.
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Affiliation(s)
- Sean A Hudson
- The University of Adelaide, South Australia, Australia
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174
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Biancalana M, Makabe K, Koide A, Koide S. Molecular mechanism of thioflavin-T binding to the surface of beta-rich peptide self-assemblies. J Mol Biol 2008; 385:1052-63. [PMID: 19038267 DOI: 10.1016/j.jmb.2008.11.006] [Citation(s) in RCA: 270] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 11/03/2008] [Accepted: 11/05/2008] [Indexed: 11/25/2022]
Abstract
A number of small organic molecules have been developed that bind to amyloid fibrils, a subset of which also inhibit fibrillization. Among these, the benzothiol dye Thioflavin-T (ThT) has been used for decades in the diagnosis of protein-misfolding diseases and in kinetic studies of self-assembly (fibrillization). Despite its importance, efforts to characterize the ThT-binding mechanism at the atomic level have been hampered by the inherent insolubility and heterogeneity of peptide self-assemblies. To overcome these challenges, we have developed a minimalist approach to designing a ThT-binding site in a "peptide self-assembly mimic" (PSAM) scaffold. PSAMs are engineered water-soluble proteins that mimic a segment of beta-rich peptide self-assembly, and they are amenable to standard biophysical techniques and systematic mutagenesis. The PSAM beta-sheet contains rows of repetitive amino acid patterns running perpendicular to the strands (cross-strand ladders) that represent a ubiquitous structural feature of fibril-like surfaces. We successfully designed a ThT-binding site that recapitulates the hallmarks of ThT-fibril interactions by constructing a cross-strand ladder consisting of contiguous tyrosines. The X-ray crystal structures suggest that ThT interacts with the beta-sheet by docking onto surfaces formed by a single tyrosine ladder, rather than in the space between adjacent ladders. Systematic mutagenesis further demonstrated that tyrosine surfaces across four or more beta-strands formed the minimal binding site for ThT. Our work thus provides structural insights into how this widely used dye recognizes a prominent subset of peptide self-assemblies, and proposes a strategy to elucidate the mechanisms of fibril-ligand interactions.
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Affiliation(s)
- Matthew Biancalana
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
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175
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Wolf MG, Jongejan JA, Laman JD, de Leeuw SW. Quantitative Prediction of Amyloid Fibril Growth of Short Peptides from Simulations: Calculating Association Constants To Dissect Side Chain Importance. J Am Chem Soc 2008; 130:15772-3. [DOI: 10.1021/ja806606y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Maarten G. Wolf
- Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Department of Immunology, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Jaap A. Jongejan
- Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Department of Immunology, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Jon D. Laman
- Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Department of Immunology, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Simon W. de Leeuw
- Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Department of Immunology, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
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176
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Madine J, Jack E, Stockley PG, Radford SE, Serpell LC, Middleton DA. Structural Insights into the Polymorphism of Amyloid-Like Fibrils Formed by Region 20−29 of Amylin Revealed by Solid-State NMR and X-ray Fiber Diffraction. J Am Chem Soc 2008; 130:14990-5001. [DOI: 10.1021/ja802483d] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jillian Madine
- School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K., Faculty of Life Sciences, University of Manchester, Manchester M60 1QD, U.K., Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K., and Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, U.K
| | - Edward Jack
- School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K., Faculty of Life Sciences, University of Manchester, Manchester M60 1QD, U.K., Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K., and Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, U.K
| | - Peter G. Stockley
- School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K., Faculty of Life Sciences, University of Manchester, Manchester M60 1QD, U.K., Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K., and Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, U.K
| | - Sheena E. Radford
- School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K., Faculty of Life Sciences, University of Manchester, Manchester M60 1QD, U.K., Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K., and Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, U.K
| | - Louise C. Serpell
- School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K., Faculty of Life Sciences, University of Manchester, Manchester M60 1QD, U.K., Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K., and Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, U.K
| | - David A. Middleton
- School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K., Faculty of Life Sciences, University of Manchester, Manchester M60 1QD, U.K., Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K., and Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, U.K
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177
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A Molecular Dynamics Study of the Interaction of d-Peptide Amyloid Inhibitors with Their Target Sequence Reveals a Potential Inhibitory Pharmacophore Conformation. J Mol Biol 2008; 383:266-80. [DOI: 10.1016/j.jmb.2008.07.076] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 07/24/2008] [Accepted: 07/25/2008] [Indexed: 11/19/2022]
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178
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Iqbal S, Miravet JF, Escuder B. Biomimetic Self-Assembly of Tetrapeptides into Fibrillar Networks and Organogels. European J Org Chem 2008. [DOI: 10.1002/ejoc.200800547] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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179
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Biancalana M, Makabe K, Koide A, Koide S. Aromatic cross-strand ladders control the structure and stability of beta-rich peptide self-assembly mimics. J Mol Biol 2008; 383:205-13. [PMID: 18762191 DOI: 10.1016/j.jmb.2008.08.031] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 08/05/2008] [Accepted: 08/14/2008] [Indexed: 10/21/2022]
Abstract
Though beta-rich self-assemblies comprise a major structural class of polypeptides, a detailed understanding of the determinants of their structure and stability is lacking. In particular, the roles of repetitive stretches of side chains running the long axis of these beta-sheets, termed "cross-strand ladders," remain poorly characterized due to the inherently insoluble and heterogeneous nature of self-assemblies. To overcome these experimental challenges, we have established a complementary experimental system termed "peptide self-assembly mimics" (PSAMs). The PSAMs capture a defined number of self-assembly-like peptide repeats within a soluble beta-rich protein, making structural and energetic studies possible. In this work, we investigated the role of cross-strand ladders containing aromatic residues, which are prominent in self-assembling peptides. A combination of solution data and high-resolution crystal structures revealed that a single cross-strand ladder consisting solely of Tyr significantly stabilized, rigidified, and flattened the PSAM beta-sheet. These characteristics would stabilize each beta-sheet layer of a self-assembly and direct sheet conformations compatible with lamination. Our results therefore provide a rationale for the abundance of aromatic amino acids in fibril-forming peptides and establish important roles of cross-strand Tyr ladders in the structure and stability of beta-rich peptide self-assemblies.
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Affiliation(s)
- Matthew Biancalana
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
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180
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McCullagh M, Prytkova T, Tonzani S, Winter ND, Schatz GC. Modeling Self-Assembly Processes Driven by Nonbonded Interactions in Soft Materials. J Phys Chem B 2008; 112:10388-98. [DOI: 10.1021/jp803192u] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Martin McCullagh
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113
| | - Tatiana Prytkova
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113
| | - Stefano Tonzani
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113
| | - Nicolas D. Winter
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113
| | - George C. Schatz
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113
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181
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Levy M, Porat Y, Bacharach E, Shalev DE, Gazit E. Phenolsulfonphthalein, but Not Phenolphthalein, Inhibits Amyloid Fibril Formation: Implications for the Modulation of Amyloid Self-Assembly. Biochemistry 2008; 47:5896-904. [DOI: 10.1021/bi800043d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michal Levy
- Department of Molecular Microbiology and Biotechnology and Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel, and The Wolfson Centre for Applied Structural Biology, Safra Campus, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Yair Porat
- Department of Molecular Microbiology and Biotechnology and Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel, and The Wolfson Centre for Applied Structural Biology, Safra Campus, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Eran Bacharach
- Department of Molecular Microbiology and Biotechnology and Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel, and The Wolfson Centre for Applied Structural Biology, Safra Campus, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Deborah E. Shalev
- Department of Molecular Microbiology and Biotechnology and Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel, and The Wolfson Centre for Applied Structural Biology, Safra Campus, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Ehud Gazit
- Department of Molecular Microbiology and Biotechnology and Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel, and The Wolfson Centre for Applied Structural Biology, Safra Campus, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
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182
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Valéry C, Pouget E, Pandit A, Verbavatz JM, Bordes L, Boisdé I, Cherif-Cheikh R, Artzner F, Paternostre M. Molecular origin of the self-assembly of lanreotide into nanotubes: a mutational approach. Biophys J 2008; 94:1782-95. [PMID: 17993497 PMCID: PMC2242760 DOI: 10.1529/biophysj.107.108175] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Accepted: 10/01/2007] [Indexed: 11/18/2022] Open
Abstract
Lanreotide, a synthetic, therapeutic octapeptide analog of somatostatin, self-assembles in water into perfectly hollow and monodisperse (24-nm wide) nanotubes. Lanreotide is a cyclic octapeptide that contains three aromatic residues. The molecular packing of the peptide in the walls of a nanotube has recently been characterized, indicating four hierarchical levels of organization. This is a fascinating example of spontaneous self-organization, very similar to the formation of the gas vesicle walls of Halobacterium halobium. However, this unique peptide self-assembly raises important questions about its molecular origin. We adopted a directed mutation approach to determine the molecular parameters driving the formation of such a remarkable peptide architecture. We have modified the conformation by opening the cycle and by changing the conformation of a Lys residue, and we have also mutated the aromatic side chains of the peptide. We show that three parameters are essential for the formation of lanreotide nanotubes: i), the specificity of two of the three aromatic side chains, ii), the spatial arrangement of the hydrophilic and hydrophobic residues, and iii), the aromatic side chain in the beta-turn of the molecule. When these molecular characteristics are modified, either the peptides lose their self-assembling capability or they form less-ordered architectures, such as amyloid fibers and curved lamellae. Thus we have determined key elements of the molecular origins of lanreotide nanotube formation.
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Affiliation(s)
- Céline Valéry
- Ipsen Pharma, 08980 Sant Feliu de Llobregat, Barcelona, Spain
| | - Emilie Pouget
- Unité mixte de Recherche du Centre National pour la Recherche Scientifique 6626, Université Rennes 1, F-35042 Rennes, France
| | - Anjali Pandit
- Institut de Bio Technologies de Saclay, Commisariat à l’Energie Atomique et Centre National pour la Recherche Scientifique, F-91191 Gif-sur-Yvette, France
| | - Jean-Marc Verbavatz
- Institut de Bio Technologies de Saclay, Commisariat à l’Energie Atomique et Centre National pour la Recherche Scientifique, F-91191 Gif-sur-Yvette, France
| | - Luc Bordes
- Institut de Bio Technologies de Saclay, Commisariat à l’Energie Atomique et Centre National pour la Recherche Scientifique, F-91191 Gif-sur-Yvette, France
| | - Isabelle Boisdé
- Institut de Bio Technologies de Saclay, Commisariat à l’Energie Atomique et Centre National pour la Recherche Scientifique, F-91191 Gif-sur-Yvette, France
| | | | - Franck Artzner
- Unité mixte de Recherche du Centre National pour la Recherche Scientifique 6626, Université Rennes 1, F-35042 Rennes, France
| | - Maité Paternostre
- Institut de Bio Technologies de Saclay, Commisariat à l’Energie Atomique et Centre National pour la Recherche Scientifique, F-91191 Gif-sur-Yvette, France
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183
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Joshi KB, Verma S. Sequence shuffle controls morphological consequences in a self-assembling tetrapeptide. J Pept Sci 2008; 14:118-26. [DOI: 10.1002/psc.955] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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184
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Abstract
The fibrillization of peptides is relevant to many diseases based on the deposition of amyloids. The formation of fibrils is being intensively studied, especially in terms of nanotechnology applications, where fibrillar peptide hydrogels are used for cell scaffolds, as supports for functional and responsive biomaterials, biosensors, and nanowires. This Review is concerned with fundamental aspects of the self-assembly of peptides into fibrils, and discusses both natural amyloid-forming peptides and synthetic materials, including peptide fragments, copolymers, and amphiphiles.
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Affiliation(s)
- Ian W Hamley
- Department of Chemistry, University of Reading, Reading, Berkshire RG6 6AD, UK.
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185
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186
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Bochicchio B, Pepe A, Tamburro AM. Elastic fibers and amyloid deposition in vascular tissue. FUTURE NEUROLOGY 2007. [DOI: 10.2217/14796708.2.5.523] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Amyloid fibrils are associated with a large number of diseases, such as Alzheimer’s dementia and others. Evidence links Alzheimer’s dementia with vascular diseases and only few data connect amyloids and atherosclerosis and aging via deposits in the aortic intima. Recent results demonstrate that some elastin polypeptide sequences are also able to produce amyloid fibers. This finding could have useful implications in the study of amyloids in cardiovascular tissue whose main constituent is elastin. In this review, we have also outlined the main characterizing features regarding the structure of amyloid fibrils. Finally, we describe, as a future perspective, the design of proper inhibitors of amyloid deposition in vascular walls as potential therapeutic drugs.
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Affiliation(s)
- Brigida Bochicchio
- University of Basilicata, Department of Chemistry, Via N. Sauro 85, 85100 Potenza, Italy
| | - Antonietta Pepe
- University of Basilicata, Department of Chemistry, Via N. Sauro 85, 85100 Potenza, Italy
| | - Antonio M Tamburro
- University of Basilicata, Department of Chemistry, Via N. Sauro 85, 85100 Potenza, Italy
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187
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Jack E, Newsome M, Stockley PG, Radford SE, Middleton DA. The organization of aromatic side groups in an amyloid fibril probed by solid-state 2H and 19F NMR spectroscopy. J Am Chem Soc 2007; 128:8098-9. [PMID: 16787049 DOI: 10.1021/ja0581898] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Some 25 diseases are associated with proteins and peptides that assemble into amyloid fibrils composed of beta-strands connected by hydrogen bonds oriented parallel to the fiber long axis. There is mounting evidence that amyloid formation involves specific interactions between amino acid side groups, which bring together beta-sheets to form layers with buried and exposed faces. This work demonstrates how a combination of solid-state 2H and 19F NMR experiments can provide constraints on fibril architecture by probing the environment and spatial organisation of aromatic side groups. It is shown that phenylalanine rings within fibrils formed by a decapeptide fragment of the islet amyloid polypeptide, amylin, are highly motionally restrained and are situated within 6.5 A of one another. Taken together with existing structural constraints for this peptide, these results are consistent with a fibril architecture that comprises layers of two or more beta-sheets, with the aromatic residues facing into the inter-sheet space and possibly engaged in pi-pi interactions. The methods presented will be of general utility in exploring the architecture of fibrils of larger, full-length peptides and proteins, including amylin itself.
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Affiliation(s)
- Edward Jack
- Faculty of Life Sciences, University of Manchester, P.O. Box 88, Manchester M60 1QD, United Kingdom
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188
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Affiliation(s)
- Wolfgang H Binder
- Vienna University of Technology, Institute of Applied Synthetic Chemistry, Vienna, Austria.
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189
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Nakano M, Shen JR, Kamino K. Self-Assembling Peptide Inspired by a Barnacle Underwater Adhesive Protein. Biomacromolecules 2007; 8:1830-5. [PMID: 17518440 DOI: 10.1021/bm0612236] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An underwater bioadhesive generally comprises a multiprotein complex that provides a molecular basis for self-assembly. We report here a new class of self-assembling peptide inspired by a 20 kDa barnacle cement protein. Studies on the chemically synthesized 24-residue peptide have revealed that (1) it underwent irreversible self-assembly upon the addition of salt, (2) the self-assembly was started at a salt concentration close to that of seawater with noncovalent intermolecular interactions, (3) the self-assembled material resembled a macroscopic membrane of interwoven nanofilaments, (4) incubation in an alkaline pH range formed the intramolecular disulfide bond of a peptide molecule, thus triggering a conformation change of the molecule, and (5) conformational change of the building block promoted the formation of a nanofiber, resulting in the display of a three-dimensional meshlike mesoscopic structure with defined pores having a diameter of approximately 200 nm. The peptide is likely to provide a suitable basis for further development of peptide-based materials.
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Affiliation(s)
- Masahiro Nakano
- Marine Biotechnology Institute, 3-75-1 Heita, Kamaishi, Iwate 026-0001, Japan
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190
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Ghosh S, Verma S. Phased Fiber Growth in a Peptide Conjugate: Aggregation and Disaggregation Studies. J Phys Chem B 2007; 111:3750-7. [PMID: 17388532 DOI: 10.1021/jp066546a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A glycine-rich, short pentapeptide conjugate 6, derived from the highly conserved copper-binding octarepeat region of the prion protein, exhibits a tendency to self-aggregate in a time-dependent fashion. Aging of 6 afforded an insight into the phased growth of spherical prefibrillar structures to fibers of long persistence length, as observed by a combination of microscopic techniques. Interestingly, growth of these fibers was inhibited by colchicine, a known inhibitor of microtubule polymerization in a concentration dependent fashion. This study offers an intriguing insight into the occurrence of prefibrillar intermediates on the path to the formation of full length peptide fibers. It is also envisaged that constructs such as 6 may also serve as simple models to study chemical intervention of protein aggregation.
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Affiliation(s)
- Surajit Ghosh
- Department of Chemistry, Indian Institute of Technology-Kanpur, Kanpur-208016 (UP), India
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191
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de Groot NS, Parella T, Aviles FX, Vendrell J, Ventura S. Ile-phe dipeptide self-assembly: clues to amyloid formation. Biophys J 2007; 92:1732-41. [PMID: 17172307 PMCID: PMC1796831 DOI: 10.1529/biophysj.106.096677] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Accepted: 11/16/2006] [Indexed: 02/06/2023] Open
Abstract
Peptidic self-assembled nanostructures are said to have a wide range of applications in nanotechnology, yet the mechanistic details of hierarchical self-assembly are still poorly understood. The Phe-Phe recognition motif of the Alzheimer's Abeta peptide is the smallest peptide able to assemble into higher-order structures. Here, we show that the Ile-Phe dipeptide analog is also able to self-associate in aqueous solution as a transparent, thermoreversible gel formed by a network of fibrillar nanostructures that exhibit strong birefringence upon Congo red binding. Besides, a second dipeptide Val-Phe, differing only in a methyl group from the former, is unable to self-assemble. The detailed analysis of the differential polymeric behavior of these closely related molecules provides insight into the forces triggering the first steps in self-assembly processes such as amyloid formation.
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Affiliation(s)
- Natalia Sánchez de Groot
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
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192
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Maskevich AA, Stsiapura VI, Kuzmitsky VA, Kuznetsova IM, Povarova OI, Uversky VN, Turoverov KK. Spectral Properties of Thioflavin T in Solvents with Different Dielectric Properties and in a Fibril-Incorporated Form. J Proteome Res 2007; 6:1392-401. [PMID: 17305383 DOI: 10.1021/pr0605567] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The increase in the solvent polarity induces a significant shift of the long-wavelength absorption band of the thioflavin T (ThT) to the shorter wavelengths. This is due to the fact that the positive charge of the ThT molecule (Z = +1e) is unequally and very differently distributed between the benzthiazole and aminobenzene rings in the ground and excited states. Therefore, ThT ground state is stabilized by the orientational interactions of the polar solvent dipoles with the positively charged ThT fragments, whereas the configuration of the solvation shell of the ThT molecule in the excited Franck-Condon state is likely far from being equilibrium. ThT absorption spectrum has the shortest (412 nm) and the longest (450 nm) wavelengths in water and in water being incorporated to the amyloid fibrils, respectively. Intriguingly, the position of the ThT fluorescence spectrum depends on the polarity of solvent to a significantly lesser degree than its absorption spectrum: being excited at 440 nm, ThT has emission with maxima at 493 and 478 nm in water and fibrils, respectively. This can be due to the fact that, in the excited state, the rotational oscillations of the ThT fragments relative to each other prevent establishing equilibrium with the solvent and fluorescence occurs from the partially equilibrium excited stated to the partially equilibrium ground state. For the fibril-incorporated ThT, the maximum of the fluorescence excitation spectrum coincides with the maximum of the long wavelength absorption band (450 nm), whereas for ThT in aqueous and alcohol solutions, additional short-wavelength bands of fluorescence and fluorescence excitation spectra were described (Naiki et al. Anal. Biochem. 1989, 177, 244-249; Le Vine Methods Enzymol. 1999, 309, 274-284). These bands could result either from some fluorescent admixtures (including free benzthiazole and aminobenzene) or from the specific ThT conformers in which benzthiazole and aminobenzene rings, being oriented at phi angle close to 90 or 270 degrees, serve as independent chromophores. On the basis of the results of the quantum-chemical calculations, it is proposed that at phi = 90 degrees (270 degrees), the relatively low barrier (only 700 cm-1) of the internal rotation of the benzthiazole and aminobenzene rings relative to each other gives rise to a subpopulation of ThT molecules possessing a violated system of the pi-conjugated bonds of the benzthiazole and aminobenzene rings.
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Yan LM, Velkova A, Tatarek-Nossol M, Andreetto E, Kapurniotu A. Ein IAPP-Mimetikum blockiert die zytotoxische Aggregation von Aβ – die Kreuzunterdrückung der Amyloidtoxizität von Aβ und IAPP deutet auf einen molekularen Zusammenhang zwischen Alzheimer-Krankheit und Typ-II-Diabetes hin. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604056] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Yan LM, Velkova A, Tatarek-Nossol M, Andreetto E, Kapurniotu A. IAPP Mimic Blocks Aβ Cytotoxic Self-Assembly: Cross-Suppression of Amyloid Toxicity of Aβ and IAPP Suggests a Molecular Link between Alzheimer's Disease and Type II Diabetes. Angew Chem Int Ed Engl 2007; 46:1246-52. [PMID: 17203498 DOI: 10.1002/anie.200604056] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Li-Mei Yan
- Laboratory of Bioorganic and Medicinal Chemistry, Institute of Biochemistry, University Hospital of the RWTH Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany
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Sano KI, Sasaki H, Shiba K. Conversion of a monodispersed globular protein into an amyloid-like filament by appending an artificial peptide at the N-terminal. Protein Eng Des Sel 2007; 20:109-16. [PMID: 17293372 DOI: 10.1093/protein/gzm001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The soluble, globular, alpha-helix-rich peptide SipA(446-684) is a domain of a bacterial protein that binds to mammalian filamentous-actin and re-arranges the host cell's cytoskeleton. We show that adding two copies of NHBP-1, a carbon nanomaterial binding peptide, to its N-terminal can induce SipA(446-684) to polymerize and assume a fibrillar structure under physiological conditions. The fibrils formed showed thioflavine T and Congo red staining profiles that are characteristic of and specific for amyloid-like structures. The alpha-helical structure of the globular protein was retained in the fibrils, suggesting the appended NHBP-1 sequence plays a key role in the formation of cross-beta spines within the fibrils. Consistent with that idea, we observed that a synthetic NHBP-1 peptide can form an amyloid-like structure under appropriate conditions. Thus, our findings add a new subtype of amyloid-like structure formation and suggest this method of assembly could be exploited in nano-biotechnology.
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Affiliation(s)
- Ken-Ichi Sano
- Department of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research and CREST, JST, Koto-Ku, Tokyo 135-8550 Japan
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Abstract
Familial Danish dementia is a neurodegenerative disease which is a consequence of alterations in the BRI gene. The pathological signatures of the disease are cerebral amyloidolysis, parenchymal protein deposits and neuronal degeneration. Synthetic Danish dementia (ADan) peptides are capable of forming fibrillar assemblies in vitro at pH 4.8. However, the morphology of the aggregates formed depends greatly on the form of the peptides (oxidized or reduced). In addition to long slender assemblies (2-5 nm in diameter and several micrometers in length) we report ring-like or annular masses (8-9 nm in diameter and 1-2 mm in perimeter) in the case of the oxidized form of the peptides. The reduced forms mainly aggregate to produce granular heaps. The biophysical and kinetic characterization of the process of aggregation was carried out using different spectroscopic and imaging techniques. Neurotoxicity assays performed on both the forms reveal that the toxicity bears proportionality with the aggregate size.
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Affiliation(s)
- Ira Surolia
- National Institute of Nutrition, Hyderabad, India
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Görbitz CH. The structure of nanotubes formed by diphenylalanine, the core recognition motif of Alzheimer's β-amyloid polypeptide. Chem Commun (Camb) 2006:2332-4. [PMID: 16733570 DOI: 10.1039/b603080g] [Citation(s) in RCA: 277] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Alzheimer's beta-amyloid diphenylalanine motif has previously been shown to self-assemble into discrete and extraordinary stiff nanotubes; these nanotubes were initially thought to be distinct from the single crystal structure of diphenylalanine, but it is now shown that the X-ray powder diffraction pattern of the nanotubes is identical to the simulated pattern for the single crystal structure, affording a new foundation for understanding and rationalizing the properties of this remarkable organic material.
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Affiliation(s)
- Carl Henrik Görbitz
- Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315, Oslo, Norway.
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