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Hamley IW. The Amyloid Beta Peptide: A Chemist’s Perspective. Role in Alzheimer’s and Fibrillization. Chem Rev 2012; 112:5147-92. [DOI: 10.1021/cr3000994] [Citation(s) in RCA: 670] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- I. W. Hamley
- Department
of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD,
U.K
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52
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Solomonov I, Korkotian E, Born B, Feldman Y, Bitler A, Rahimi F, Li H, Bitan G, Sagi I. Zn2+-Aβ40 complexes form metastable quasi-spherical oligomers that are cytotoxic to cultured hippocampal neurons. J Biol Chem 2012; 287:20555-64. [PMID: 22528492 DOI: 10.1074/jbc.m112.344036] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The roles of metal ions in promoting amyloid β-protein (Aβ) oligomerization associated with Alzheimer disease are increasingly recognized. However, the detailed structures dictating toxicity remain elusive for Aβ oligomers stabilized by metal ions. Here, we show that small Zn(2+)-bound Aβ1-40 (Zn(2+)-Aβ40) oligomers formed in cell culture medium exhibit quasi-spherical structures similar to native amylospheroids isolated recently from Alzheimer disease patients. These quasi-spherical Zn(2+)-Aβ40 oligomers irreversibly inhibit spontaneous neuronal activity and cause massive cell death in primary hippocampal neurons. Spectroscopic and x-ray diffraction structural analyses indicate that despite their non-fibrillar morphology, the metastable Zn(2+)-Aβ40 oligomers are rich in β-sheet and cross-β structures. Thus, Zn(2+) promotes Aβ40 neurotoxicity by structural organization mechanisms mediated by coordination chemistry.
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Affiliation(s)
- Inna Solomonov
- Department of Structural Biology, The Weizmann Institute of Science, Rehovot 76100, Israel
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53
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Inoue M, Konno T, Tainaka K, Nakata E, Yoshida HO, Morii T. Positional effects of phosphorylation on the stability and morphology of tau-related amyloid fibrils. Biochemistry 2012; 51:1396-406. [PMID: 22304362 DOI: 10.1021/bi201451z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hyperphosphorylated forms of tau protein are the main component of paired helical filaments (PHFs) of neurofibrillary tangles in the brain of Alzheimer's disease patients. To understand the effect of phosphorylation on the fibrillation of tau, we utilized tau-derived phosphorylated peptides. The V(306)QIVYK(311) sequence (PHF6) in the microtubule-binding domain is known to play a key role in the fibrillation of tau, and the short peptide corresponding to the PHF6 sequence forms amyloid-type fibrils similar to those generated by full-length tau. We focused on the amino acid residue located at the N-terminus of the PHF6 sequence, serine or lysine in the native isoform of tau, and synthesized the PHF6 derivative peptides with serine or lysine at the N-terminus of PHF6. Peptides phosphorylated at serine and/or tyrosine were synthesized to mimic the possible phosphorylation at these positions. The critical concentrations of the fibrillation of peptides were determined to quantitatively assess fibril stability. The peptide with the net charge of near zero tended to form stable fibrils. Interestingly, the peptide phosphorylated at the N-terminal serine residue exhibited remarkably low fibrillation propensity as compared to the peptide possessing the same net charge. Transmission electron microscopy measurements of the fibrils visualized the paired helical or straight fibers and segregated masses of the fibers or heterogeneous rodlike fibers depending on the phosphorylation status. Further analyses of the fibrils by the X-ray fiber diffraction method and Fourier transform infrared spectroscopic measurements indicated that all the peptides shared a common cross-β structure. In addition, the phosphoserine-containing peptides showed the characteristics of β-sandwiches that could interact with both faces of the β-sheet. On the basis of these observations, possible protofilament models with four β-sheets were constructed to consider the positional effects of the serine and/or tyrosine phosphorylations. The electrostatic intersheet interaction between phosphate groups and the amino group of lysine enhanced the lateral association between β-sheets to compensate for the excess charge. In addition to the previously postulated net charge of the peptide, the position of the charged residue plays a critical role in the amyloid fibrillation of tau.
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Affiliation(s)
- Masafumi Inoue
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
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54
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Doran TM, Anderson EA, Latchney SE, Opanashuk LA, Nilsson BL. Turn nucleation perturbs amyloid β self-assembly and cytotoxicity. J Mol Biol 2012; 421:315-28. [PMID: 22326870 DOI: 10.1016/j.jmb.2012.01.055] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 01/27/2012] [Accepted: 01/31/2012] [Indexed: 10/14/2022]
Abstract
The accumulation of senile plaques composed of amyloid β (Aβ) fibrils is a hallmark of Alzheimer's disease, although prefibrillar oligomeric species are believed to be the primary neurotoxic congeners in the pathogenesis of Alzheimer's disease. Uncertainty regarding the mechanistic relationship between Aβ oligomer and fibril formation and the cytotoxicity of these aggregate species persists. β-Turn formation has been proposed to be a potential rate-limiting step during Aβ fibrillogenesis. The effect of turn nucleation on Aβ self-assembly was probed by systematically replacing amino acid pairs in the putative turn region of Aβ (residues 24-27) with d-ProGly ((D)PG), an effective turn-nucleating motif. The kinetic, thermodynamic, and cytotoxic effects of these mutations were characterized. It was found that turn formation dramatically accelerated Aβ fibril self-assembly dependent on the site of turn nucleation. The cytotoxicity of the three (D)PG-containing Aβ variants was significantly lower than that of wild-type Aβ40, presumably due to decreased oligomer populations as a function of a more rapid progression to mature fibrils; oligomer populations were not eliminated, however, suggesting that turn formation is also a feature of oligomer structures. These results indicate that turn nucleation is a critical step in Aβ40 fibril formation.
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Affiliation(s)
- Todd M Doran
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA
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55
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Abstract
Amyloid fibrils are polymeric assemblies of normally soluble proteins or peptides. To investigate their structure, it is generally not possible to use conventional methods of crystallography and solution nuclear magnetic resonance. To examine the repeating crystalline structure along the fibre axis, X-ray fibre diffraction has been a useful tool. Here we discuss the methods by which amyloid-like fibrils may be prepared to form a sample suitable for structural analysis and describe how data may be collected and then analysed to arrive at a potential model structure.
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56
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Pauwels K, Williams TL, Morris KL, Jonckheere W, Vandersteen A, Kelly G, Schymkowitz J, Rousseau F, Pastore A, Serpell LC, Broersen K. Structural basis for increased toxicity of pathological aβ42:aβ40 ratios in Alzheimer disease. J Biol Chem 2011; 287:5650-60. [PMID: 22157754 DOI: 10.1074/jbc.m111.264473] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The β-amyloid peptide (Aβ) is directly related to neurotoxicity in Alzheimer disease (AD). The two most abundant alloforms of the peptide co-exist under normal physiological conditions in the brain in an Aβ(42):Aβ(40) ratio of ∼1:9. This ratio is often shifted to a higher percentage of Aβ(42) in brains of patients with familial AD and this has recently been shown to lead to increased synaptotoxicity. The molecular basis for this phenomenon is unclear. Although the aggregation characteristics of Aβ(40) and Aβ(42) individually are well established, little is known about the properties of mixtures. We have explored the biophysical and structural properties of physiologically relevant Aβ(42):Aβ(40) ratios by several techniques. We show that Aβ(40) and Aβ(42) directly interact as well as modify the behavior of the other. The structures of monomeric and fibrillar assemblies formed from Aβ(40) and Aβ(42) mixtures do not differ from those formed from either of these peptides alone. Instead, the co-assembly of Aβ(40) and Aβ(42) influences the aggregation kinetics by altering the pattern of oligomer formation as evidenced by a unique combination of solution nuclear magnetic resonance spectroscopy, high molecular weight mass spectrometry, and cross-seeding experiments. We relate these observations to the observed enhanced toxicity of relevant ratios of Aβ(42):Aβ(40) in synaptotoxicity assays and in AD patients.
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Affiliation(s)
- Kris Pauwels
- Division of Molecular Structure, Medical Research Council National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
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Sambasivam D, Sivanesan S, Ashok BS, Rajadas J. Structural preferences of Aβ fragments in different micellar environments. Neuropeptides 2011; 45:369-76. [PMID: 22019176 DOI: 10.1016/j.npep.2011.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 09/19/2011] [Accepted: 09/19/2011] [Indexed: 10/16/2022]
Abstract
Amyloid diseases occur due to conformational change in the native protein. Understanding the amyloid peptide structural stability and conformational preference at the molecular level in membranous environment may lead to advancement in drug design and therapy. The conformational preferences of amyloid peptide fragments, Aβ₁₋₁₁, Aβ₁₂₋₂₂, Aβ₂₃₋₃₃ and Aβ₃₄₋₄₂ was studied in buffers, trifluoroethanol (TFE) and sodium dodecyl sulfate (SDS) micelles using circular dichroism spectroscopy. The fragment, Aβ₁₋₁₁ in TFE adopts a mixture of random coil and turn conformations. Aβ₁₂₋₂₂ and Aβ₂₃₋₃₃ underwent transition from random coil to helix conformation, while Aβ₃₄₋₄₂ exhibited β-sheet conformation in initial stage which was unaltered on complete evaporation of TFE. Addition of SDS to Aβ₁₂₋₂₂ and Aβ₃₄₋₄₂ favors β-sheet structure, which was predominant in the case of Aβ₃₄₋₄₂. However, in Aβ₁₋₁₁ and Aβ₂₃₋₃₃, no secondary structural change was noticed even at high SDS concentrations. On aging, all the peptide fragments showed β-sheet conformational transition. The C-terminal fragment has the ability to adopt predominant β-sheet conformation even in the presence of detergent and membrane mimicking environment. Altogether, the structural information gained from the short fragments could be further used for determining their role in the organization of Aβ peptide in stable fibril form.
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58
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Masuda Y, Fukuchi M, Yatagawa T, Tada M, Takeda K, Irie K, Akagi KI, Monobe Y, Imazawa T, Takegoshi K. Solid-state NMR analysis of interaction sites of curcumin and 42-residue amyloid β-protein fibrils. Bioorg Med Chem 2011; 19:5967-74. [DOI: 10.1016/j.bmc.2011.08.052] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 08/24/2011] [Accepted: 08/24/2011] [Indexed: 12/28/2022]
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59
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Substituted tryptophans at amyloid-β(1-40) residues 19 and 20 experience different environments after fibril formation. Arch Biochem Biophys 2011; 514:27-32. [PMID: 21843498 DOI: 10.1016/j.abb.2011.07.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 07/29/2011] [Accepted: 07/30/2011] [Indexed: 11/20/2022]
Abstract
Amyloid-β protein (Aβ) is the principal component of the neuritic plaques found in Alzheimer's disease. The predominant Aβ morphology in the plaques is fibrillar which has prompted substantial in vitro work to better understand the molecular organization of Aβ fibrils. In the current study, tryptophan substitutions were made at Aβ(1-40) position 19 (F19W) or 20 (F20W) to ascertain environmental differences between the two residues in the fibril structure. Kinetic studies revealed similar rates of fibril formation between Aβ(1-40) F19W and F20W and both peptides formed typical amyloid fibril structures. Aβ(1-40) F19W fibrils displayed a significant tryptophan fluorescence blue-shift in λ(max) (33nm) compared to monomer while Aβ(1-40) F20W fibrils had a much smaller shift (9nm). Fluorescence quenching experiments with water-soluble acrylamide and KI demonstrated that both W19 and W20 were much less accessible to quenching in fibrils compared to monomer. Lipid-soluble TEMPO quenched the fluorescence of Aβ(1-40) F19W fibrils more effectively than F20W fibrils in agreement with the fluorescence blue-shift results. These findings demonstrate distinct environments between Aβ(1-40) residues 19 and 20 fibrils and indicate that while W20 accessibility is compromised in Aβ fibrils it resides in a much less hydrophobic environment than W19.
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60
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Computational insights into the development of novel therapeutic strategies for Alzheimer's disease. Future Med Chem 2011; 1:119-35. [PMID: 21426072 DOI: 10.4155/fmc.09.10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND β-amyloidosis and oxidative stress have been implicated as root causes of Alzheimer's disease (AD). Current potential therapeutic strategies for the treatment of AD include inhibition of amyloid β (Aβ) production, stimulation of Aβ degradation and prevention of Aβ oligomerization. However, efforts in this direction are hindered by the lack of understanding of the biochemical processes occurring at the atomic level in AD. DISCUSSION A radically different approach to achieve this goal would be the application of comprehensive theoretical and computational techniques such as molecular dynamics, quantum mechanics, hybrid quantum mechanics/molecular mechanics, bioinformatics and rotational spectroscopy to investigate complex chemical and physical processes in β-amyloidosis and the oxidative stress mechanism. CONCLUSION Results obtained from these studies will provide an atomic level understanding of biochemical processes occurring in AD and advance efforts to develop effective therapeutic strategies for this disease.
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61
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Crystal structure of the amyloid-β p3 fragment provides a model for oligomer formation in Alzheimer's disease. J Neurosci 2011; 31:1419-26. [PMID: 21273426 DOI: 10.1523/jneurosci.4259-10.2011] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alzheimer's disease is a progressive neurodegenerative disorder associated with the presence of amyloid-β (Aβ) peptide fibrillar plaques in the brain. However, current evidence suggests that soluble nonfibrillar Aβ oligomers may be the major drivers of Aβ-mediated synaptic dysfunction. Structural information on these Aβ species has been very limited because of their noncrystalline and unstable nature. Here, we describe a crystal structure of amylogenic residues 18-41 of the Aβ peptide (equivalent to the p3 α/γ-secretase fragment of amyloid precursor protein) presented within the CDR3 loop region of a shark Ig new antigen receptor (IgNAR) single variable domain antibody. The predominant oligomeric species is a tightly associated Aβ dimer, with paired dimers forming a tetramer in the crystal caged within four IgNAR domains, preventing uncontrolled amyloid formation. Our structure correlates with independently observed features of small nonfibrillar Aβ oligomers and reveals conserved elements consistent with residues and motifs predicted as critical in Aβ folding and oligomerization, thus potentially providing a model system for nonfibrillar oligomer formation in Alzheimer's disease.
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62
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Inouye H, Gleason KA, Zhang D, Decatur SM, Kirschner DA. Differential effects of Phe19 and Phe20 on fibril formation by amyloidogenic peptide A beta 16-22 (Ac-KLVFFAE-NH2). Proteins 2010; 78:2306-21. [PMID: 20544966 DOI: 10.1002/prot.22743] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The sequence KLVFFAE (A beta 16-22) in Alzheimer's beta-amyloid is thought to be a core beta-structure that could act as a template for folding other parts of the polypeptide or molecules into fibrillar assemblies rich in beta-sheet. To elucidate the mechanism of the initial folding process, we undertook combined X-ray fiber/powder diffraction and infrared (IR) spectroscopy to analyze lyophilized A beta 16-22 and solubilized/dried peptide containing nitrile probes at F19 and/or F20. Solubilized/dried wild-type (WT) A beta 16-22 and the peptide containing cyanophenylalanine at F19 (19CN) or at F20 (20CN) gave fiber patterns consistent with slab-like beta-crystallites that were cylindrically averaged around the axis parallel to the polypeptide chain direction. The WT and 19CN assemblies showed 30-A period arrays arising from the stacking of the slabs along the peptide chain direction, whereas the 20CN assemblies lacked any such stacking. The electron density projection along the peptide chain direction indicated similar side-chain dispositions for WT and 20CN, but not for 19CN. These X-ray results and modeling imply that in the assembly of WT A beta 16-22 the F19 side chain is localized within the intersheet space and is involved in hydrophobic contact with amino acids across the intersheet space, whereas the F20 side chain localized near the slab surface is less important for the intersheet interaction, but involved in slab stacking. IR observations for the same peptides in dilute solution showed a greater degree of hydrogen bonding for the nitrile groups in 20CN than in 19CN, supporting this interpretation.
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Affiliation(s)
- Hideyo Inouye
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467, USA
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63
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Wu H, Canfield A, Adhikari J, Huo S. Quantum mechanical studies on model alpha-pleated sheets. J Comput Chem 2010; 31:1216-23. [PMID: 19827141 DOI: 10.1002/jcc.21408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Pauling and Corey proposed a pleated-sheet configuration, now called alpha-sheet, as one of the protein secondary structures in addition to alpha-helix and beta-sheet. Recently, it has been suggested that alpha-sheet is a common feature of amyloidogenic intermediates. We have investigated the stability of antiparallel beta-sheet and two conformations of alpha-sheet in solution phase using the density functional theoretical method. The peptides are modeled as two-strand acetyl-(Ala)(2)-N-methylamine. Using stages of geometry optimization and single point energy calculation at B3LYP/cc-pVTZ//B3LYP/6-31G* level and including zero-point energies, thermal, and entropic contribution, we have found that beta-sheet is the most stable conformation, while the alpha-sheet proposed by Pauling and Corey has 13.6 kcal/mol higher free energy than the beta-sheet. The alpha-sheet that resembles the structure observed in molecular dynamics simulations of amyloidogenic proteins at low pH becomes distorted after stages of geometry optimization in solution. Whether the alpha-sheets with longer chains would be increasingly favorable in water relative to the increase in internal energy of the chain needs further investigation. Different from the quantum mechanics results, AMBER parm94 force field gives small difference in solution phase energy between alpha-sheet and beta-sheet. The predicted amide I IR spectra of alpha-sheet shows the main band at higher frequency than beta-sheet.
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Affiliation(s)
- Hao Wu
- Gustaf H. Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, Massachusetts 01610, USA
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64
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Ostapchenko VG, Sawaya MR, Makarava N, Savtchenko R, Nilsson KPR, Eisenberg D, Baskakov IV. Two amyloid States of the prion protein display significantly different folding patterns. J Mol Biol 2010; 400:908-21. [PMID: 20553730 DOI: 10.1016/j.jmb.2010.05.051] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 04/27/2010] [Accepted: 05/21/2010] [Indexed: 12/16/2022]
Abstract
It has been well established that a single amino acid sequence can give rise to several conformationally distinct amyloid states. The extent to which amyloid structures formed within the same sequence are different, however, remains unclear. To address this question, we studied two amyloid states (referred to as R- and S-fibrils) produced in vitro from highly purified full-length recombinant prion protein. Several biophysical techniques including X-ray diffraction, CD, Fourier transform infrared spectroscopy (FTIR), hydrogen-deuterium exchange, proteinase K digestion, and binding of a conformation-sensitive fluorescence dye revealed that R- and S-fibrils have substantially different secondary, tertiary, and quaternary structures. While both states displayed a 4. 8-A meridional X-ray diffraction typical for amyloid cross-beta-spines, they showed markedly different equatorial profiles, suggesting different folding pattern of beta-strands. The experiments on hydrogen-deuterium exchange monitored by FTIR revealed that only small fractions of amide protons were protected in R- or S-fibrils, an argument for the dynamic nature of their cross-beta-structure. Despite this fact, both amyloid states were found to be very stable conformationally as judged from temperature-induced denaturation monitored by FTIR and the conformation-sensitive dye. Upon heating to 80 degrees C, only local unfolding was revealed, while individual state-specific cross-beta features were preserved. The current studies demonstrated that the two amyloid states formed by the same amino acid sequence exhibited significantly different folding patterns that presumably reflect two different architectures of cross-beta-structure. Both S- and R-fibrils, however, shared high conformational stability, arguing that the energy landscape for protein folding and aggregation can contain several deep free-energy minima.
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Affiliation(s)
- Valeriy G Ostapchenko
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, MD 21201, USA
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65
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Numata K, Kaplan DL. Mechanisms of enzymatic degradation of amyloid Beta microfibrils generating nanofilaments and nanospheres related to cytotoxicity. Biochemistry 2010; 49:3254-60. [PMID: 20196618 DOI: 10.1021/bi902134p] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloid beta (Abeta) fibrils are found in the brain tissue of persons with Alzheimer's disease (AD), where they accumulate as plaques. One way to reduce the level of accumulation of Abeta in the brain and potentially treat AD is with Abeta-degrading enzymes such as neprilysin (NEP) and insulin-degrading enzyme (IDE). However, enzymatic responses and degradation mechanisms of Abeta fibrils (crystalline-state Abeta) have not been investigated, particularly with respect to how to avoid cytotoxicity of the degradation products to neuronal cells. Thus, insight into mechanisms of enzymatic degradation of Abeta fibrils would be instructive as a route to elucidating different structural features related to degradation and to cytotoxicity. We report mechanisms of enzymatic degradation of Abeta with cross-beta structures and show the series of steps involved in the digestion of Abeta microfibrils to nanospheres or nanofilaments by protease XIV or alpha-chymotrypsin, respectively. These degradation products, which contained almost the same secondary structures, exhibited different cytotoxicities, indicating that relationships between nanoassembled structures and cytotoxicity of Abeta peptides are more significant than the beta-sheet content. In addition, the enzymatic digestion at the Lys28 loop region linking the two beta-sheets in Abeta fibrils is suggested as a key target related to cytotoxicity, a feature that can be selectively targeted on the basis of the choice of protease.
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Affiliation(s)
- Keiji Numata
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, USA
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66
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Groenning M. Binding mode of Thioflavin T and other molecular probes in the context of amyloid fibrils-current status. J Chem Biol 2010; 3:1-18. [PMID: 19693614 PMCID: PMC2816742 DOI: 10.1007/s12154-009-0027-5] [Citation(s) in RCA: 441] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 08/04/2009] [Indexed: 10/20/2022] Open
Abstract
Because understanding amyloid fibrillation in molecular detail is essential for development of strategies to control amyloid formation and overcome neurodegenerative disorders, increased understanding of present molecular probes as well as development of new probes are of utmost importance. To date, the binding modes of these molecular probes to amyloid fibrils are by no means adequately described or understood, and the large number of studies on Thioflavin T (ThT) and Congo Red (CR) binding have resulted in models that are incomplete and conflicting. Different types of binding sites are likely to be present in amyloid fibrils with differences in binding modes. ThT may bind in channels running parallel to the long axis of the fibril. In the channels, ThT may bind in either a monomeric or dimeric form of which the molecular conformation is likely to be planar. CR may bind in grooves formed along the β-sheets as a planar molecule in either a monomeric or supramolecular form.
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Affiliation(s)
- Minna Groenning
- Department of Pharmaceutics and Analytical Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
- IFM, Department of Chemistry, Linköping University, 581 83 Linköping, Sweden
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67
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On the metal ion (Zn2+, Cu2+) coordination with beta-amyloid peptide: DFT computational study. Interdiscip Sci 2010; 2:57-69. [DOI: 10.1007/s12539-010-0086-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 11/10/2009] [Accepted: 11/11/2009] [Indexed: 01/02/2023]
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68
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Harris JR, Milton NGN. Cholesterol in Alzheimer's disease and other amyloidogenic disorders. Subcell Biochem 2010; 51:47-75. [PMID: 20213540 DOI: 10.1007/978-90-481-8622-8_2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The complex association of cholesterol metabolism and Alzheimer's disease is presented in depth, including the possible benefits to be gained from cholesterol-lowering statin therapy. Then follows a survey of the role of neuronal membrane cholesterol in Abeta pore formation and Abeta fibrillogenesis, together with the link with membrane raft domains and gangliosides. The contribution of structural studies to Abeta fibrillogenesis, using TEM and AFM, is given some emphasis. The role of apolipoprotein E and its isoforms, in particular ApoE4, in cholesterol and Abeta binding is presented, in relation to genetic risk factors for Alzheimer's disease. Increasing evidence suggests that cholesterol oxidation products are of importance in generation of Alzheimer's disease, possibly induced by Abeta-produced hydrogen peroxide. The body of evidence for a link between cholesterol in atherosclerosis and Alzheimer's disease is increasing, along with an associated inflammatory response. The possible role of cholesterol in tau fibrillization, tauopathies and in some other non-Abeta amyloidogenic disorders is surveyed.
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Affiliation(s)
- J Robin Harris
- Institute of Zoology, University of Mainz, D-55099, Mainz, Germany.
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69
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Castelletto V, Nutt DR, Hamley IW, Bucak S, Cenker Ç, Olsson U. Structure of single-wall peptide nanotubes: in situ flow aligning X-ray diffraction. Chem Commun (Camb) 2010; 46:6270-2. [DOI: 10.1039/c0cc00212g] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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70
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Niu L, Ma X, Liu L, Mao X, Wu D, Yang Y, Zeng Q, Wang C. Molecularly tuned peptide assemblies at the liquid–solid interface studied by scanning tunneling microscopy. Phys Chem Chem Phys 2010; 12:11683-7. [DOI: 10.1039/b923927h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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71
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Liu L, Zhang L, Mao X, Niu L, Yang Y, Wang C. Chaperon-mediated single molecular approach toward modulating Abeta peptide aggregation. NANO LETTERS 2009; 9:4066-4072. [PMID: 19842691 DOI: 10.1021/nl902256b] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report here a single molecular approach using chaperone-like molecular modulators for modulating the aggregation behavior of a vital analogue of beta-amyloid peptide (Abeta) by using scanning tunneling microscopy. The molecular structures of the beta-sheets for Abeta33-42 peptide are revealed, which are keen to the aggregation of Abeta42 relating to Alzheimer's disease. It was identified that the introduction of chaperone-like modulators could regulate the assembling behavior of the peptide at molecular level. Furthermore, the modulators could also significantly accelerate the aggregation of the peptide in aqueous solution as revealed by light scattering studies. These observations of the molecular modulator effect in peptide assemblies could provide a novel approach toward modulating Abeta peptide aggregations.
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Affiliation(s)
- Lei Liu
- National Center for Nanoscience and Technology Beijing 100190, China
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72
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Milton NG, Harris JR. Polymorphism of amyloid-β fibrils and its effects on human erythrocyte catalase binding. Micron 2009; 40:800-10. [DOI: 10.1016/j.micron.2009.07.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2009] [Revised: 07/01/2009] [Accepted: 07/02/2009] [Indexed: 11/28/2022]
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73
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Hwang W, Kim BH, Dandu R, Cappello J, Ghandehari H, Seog J. Surface Induced nanofiber growth by self-assembly of a silk-elastin-like protein polymer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:12682-6. [PMID: 19803470 PMCID: PMC2783466 DOI: 10.1021/la9015993] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Many synthetic and natural peptides are known to self-assemble to form various nanostructures. During the self-assembling process, environmental conditions such as salt concentration, pH, temperature, and surface characteristics play a critical role by influencing intermolecular interactions, and hence the process of self-assembly. Here we studied the self-assembly of a genetically engineered protein polymer composed of silk-like and elastin-like repeats on a mica surface. Silk-elastin-like protein polymers (SELPs) consist of tandem repeats of Gly-Ala-Gly-Ala-Gly-Ser from Bombyx mori (silkworm) and Gly-Val-Gly-Val-Pro from mammalian elastin. At a very low polymer concentration of 1 mug/mL, SELPs self-assembled into nanofibrous structures on a mica surface. Examination using atomic force microscopy (AFM) and dynamic light scattering techniques showed that SELPs self-assembled into nanofibers in the presence of the mica surface but not in the bulk state. Ionic strength had a significant influence on nanofiber growth, indicating the importance of electrostatic interactions between the polymer and the mica surface. At low ionic strength, the kinetics of nanofiber growth showed that the mica surface effectively removed a lag phase by providing nucleating sites, facilitating nanofiber self-assembly of SELPs. Furthermore, self-assembly on additional substrates such as silicon and a hydrophobic pyrolytic carbon surface revealed that the charged hydrophilic surface provides the optimal surface to facilitate self-assembly of SELPs.
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Affiliation(s)
- Wonseok Hwang
- Department of Materials Science and Engineering and Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Bo-Hyun Kim
- Department of Materials Science and Engineering and Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Ramesh Dandu
- Department of Pharmaceutical Sciences and Center for Nanomedicine and Cellular Delivery, University of Maryland, Baltimore, Baltimore, MD, USA
| | | | - Hamidreza Ghandehari
- Departments of Pharmaceutics and Pharmaceutical Chemistry and Bioengineering
- Utah Center for Nanomedicine, Nano Institute of Utah, University of Utah, UT, USA
| | - Joonil Seog
- Department of Materials Science and Engineering and Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
- Corresponding Author Tel: 301-405-1885 Fax: 301-314-2029
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74
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Hwang W, Kim BH, Dandu R, Cappello J, Ghandehari H, Seog J. Surface Induced nanofiber growth by self-assembly of a silk-elastin-like protein polymer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009. [PMID: 19803470 DOI: 10.102l/la9015993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Many synthetic and natural peptides are known to self-assemble to form various nanostructures. During the self-assembling process, environmental conditions such as salt concentration, pH, temperature, and surface characteristics play a critical role by influencing intermolecular interactions, and hence the process of self-assembly. Here we studied the self-assembly of a genetically engineered protein polymer composed of silk-like and elastin-like repeats on a mica surface. Silk-elastin-like protein polymers (SELPs) consist of tandem repeats of Gly-Ala-Gly-Ala-Gly-Ser from Bombyx mori (silkworm) and Gly-Val-Gly-Val-Pro from mammalian elastin. At a very low polymer concentration of 1 mug/mL, SELPs self-assembled into nanofibrous structures on a mica surface. Examination using atomic force microscopy (AFM) and dynamic light scattering techniques showed that SELPs self-assembled into nanofibers in the presence of the mica surface but not in the bulk state. Ionic strength had a significant influence on nanofiber growth, indicating the importance of electrostatic interactions between the polymer and the mica surface. At low ionic strength, the kinetics of nanofiber growth showed that the mica surface effectively removed a lag phase by providing nucleating sites, facilitating nanofiber self-assembly of SELPs. Furthermore, self-assembly on additional substrates such as silicon and a hydrophobic pyrolytic carbon surface revealed that the charged hydrophilic surface provides the optimal surface to facilitate self-assembly of SELPs.
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Affiliation(s)
- Wonseok Hwang
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
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75
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Fändrich M, Meinhardt J, Grigorieff N. Structural polymorphism of Alzheimer Abeta and other amyloid fibrils. Prion 2009; 3:89-93. [PMID: 19597329 PMCID: PMC2712605 DOI: 10.4161/pri.3.2.8859] [Citation(s) in RCA: 196] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Deposits of amyloid fibrils characterize a diverse group of human diseases that includes Alzheimer's disease, Creutzfeldt-Jakob disease and type II diabetes. Amyloid fibrils formed from different polypeptides contain a common cross-beta spine. Nevertheless, amyloid fibrils formed from the same polypeptide can occur in a range of structurally different morphologies. The heterogeneity of amyloid fibrils reflects different types of polymorphism: (i) variations in the protofilament number, (ii) variations in the protofilament arrangement and (iii) different polypeptide conformations. Amyloid fibril polymorphism implies that fibril formation can lead, for the same polypeptide sequence, to many different patterns of inter- or intra-residue interactions. This property differs significantly from native, monomeric protein folding reactions that produce, for one protein sequence, only one ordered conformation and only one set of inter-residue interactions.
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Affiliation(s)
- Marcus Fändrich
- Max Planck Research Unit for Enzymology of Protein Folding and Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany.
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76
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Barrio JR, Satyamurthy N, Huang SC, Petrič A, Small GW, Kepe V. Dissecting molecular mechanisms in the living brain of dementia patients. Acc Chem Res 2009; 42:842-50. [PMID: 19281227 DOI: 10.1021/ar800189x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the molecular mechanisms associated with the development of dementia is essential for designing successful interventions. Dementia, like cancer and cardiovascular disease, requires early detection to potentially arrest or prevent further disease progression. By the time a neurologist begins to manage clinical symptoms, the disease has often damaged the brain significantly. Because successful treatment is the logical goal, detecting the disease when brain damage is still limited is of the essence. The role of chemistry in this discovery process is critical. With the advent of molecular imaging, the understanding of molecular mechanisms in human neurodegenerative diseases has exploded. Traditionally, knowledge of enzyme and neurotransmitter function in humans has been extrapolated from animal studies, but now we can acquire data directly from both healthy and diseased human subjects. In this Account, we describe the use of molecular imaging probes to elucidate the biochemical and cellular bases of dementia (e.g., Alzheimer's disease) and the application of these discoveries to the design of successful therapeutic interventions. Molecular imaging permits observation and evaluation of the basic molecular mechanisms of disease progression in the living brains of patients. 2-Deoxy-2-[(18)F]fluoro-d-glucose is used to assess the effect of Alzheimer's disease progression on neuronal circuits projecting from and to the temporal lobe (one of the earliest metabolic signs of the disease). Recently, we have developed imaging probes for detection of amyloid neuropathology (both tau and beta-amyloid peptide deposits) and neuronal losses. These probes allow us to visualize the development of pathology in the living brain of dementia patients and its consequences, such as losses of critical neurons associated with memory deficits and other neuropsychiatric impairments. Because inflammatory processes are tightly connected to the brain degenerative processes, inflammation is now emerging as an important target for new molecular imaging probes. The combination of molecular probes targeting various processes of dementia is a useful tool for detailed monitoring of disease mechanism, progression, and diagnosis, as well as for the development of rational strategies for promising therapeutic interventions.
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Affiliation(s)
| | | | | | - Andrej Petrič
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerèeva 5, 1000 Ljubljana, Slovenia
| | - Gary W. Small
- Department of Psychiatry and Biobehavioral Sciences, and Semel Institute for Neuroscience and Human Behavior
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77
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Olofsson A, Lindhagen-Persson M, Vestling M, Sauer-Eriksson AE, Ohman A. Quenched hydrogen/deuterium exchange NMR characterization of amyloid-beta peptide aggregates formed in the presence of Cu2+ or Zn2+. FEBS J 2009; 276:4051-60. [PMID: 19549187 DOI: 10.1111/j.1742-4658.2009.07113.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alzheimer's disease, a neurodegenerative disorder causing synaptic impairment and neuronal cell death, is strongly correlated with aggregation of the amyloid-beta peptide (Abeta). Divalent metal ions such as Cu(2+) and Zn(2+) are known to significantly affect the rate of aggregation and morphology of Abeta assemblies in vitro and are also found at elevated levels within cerebral plaques in vivo. The present investigation characterized the architecture of the aggregated forms of Abeta(1-40) and Abeta(1-42) in the presence or absence of either Cu(2+) or Zn(2+) using quenched hydrogen/deuterium exchange combined with solution NMR spectroscopy. The NMR analyses provide a quantitative and residue-specific structural characterization of metal-induced Abeta aggregates, showing that both the peptide sequence and the type of metal ion exert an impact on the final architecture. Common features among the metal-complexed peptide aggregates are two solvent-protected regions with an intervening minimum centered at Asn27, and a solvent-accessible N-terminal region, Asp1-Lys16. Our results suggest that Abeta in complex with either Cu(2+) or Zn(2+) can attain an aggregation-prone beta-strand-turn-beta-strand motif, similar to the motif found in fibrils, but where the metal binding to the N-terminal region guides the peptide into an assembly distinctly different from the fibril form.
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Affiliation(s)
- Anders Olofsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden.
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78
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Affiliation(s)
- Finizia Auriemma
- Dipartimento di Chimica “Paolo Corradini”, Università di Napoli “Federico II”, Complesso Monte S.Angelo, Via Cintia, I-80126 Napoli, Italy
| | - Claudio De Rosa
- Dipartimento di Chimica “Paolo Corradini”, Università di Napoli “Federico II”, Complesso Monte S.Angelo, Via Cintia, I-80126 Napoli, Italy
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79
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Amyloid beta (1-42) folding multiplicity and single-molecule binding behavior studied with STM. J Mol Biol 2009; 388:894-901. [PMID: 19328210 DOI: 10.1016/j.jmb.2009.03.054] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 01/21/2009] [Accepted: 03/15/2009] [Indexed: 01/08/2023]
Abstract
The fine folding and assembling characteristics of amyloid beta (Abeta) peptides are important to pharmaceutical studies of drug molecules and to the pathological analysis of neurodegenerative disorders such as Alzheimer's disease at the molecular level. Here we present observations of the multiple folding characteristics of amyloid peptide Abeta(42) lamellae using scanning tunneling microscopy. Molecularly resolved core regions of Abeta(42) hairpins and unfolded peptide assembly structures are identified. The parallel assembling characteristics of Abeta(42) hairpins can be confirmed in the study. In addition, single-molecule binding characteristics of Congo red and thioflavin T have been shown to bind at the groove regions of peptide assemblies. This study demonstrates a complementary venue for studying molecular heterogeneity of peptide assemblies, as well as the binding characteristics of molecular modulators.
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80
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Morris AM, Watzky MA, Finke RG. Protein aggregation kinetics, mechanism, and curve-fitting: A review of the literature. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1794:375-97. [DOI: 10.1016/j.bbapap.2008.10.016] [Citation(s) in RCA: 507] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 10/17/2008] [Accepted: 10/27/2008] [Indexed: 11/25/2022]
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81
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Yang C, Li J, Li Y, Zhu X. The effect of solvents on the conformations of Amyloid β-peptide (1–42) studied by molecular dynamics simulation. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.theochem.2008.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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82
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Faller P, Hureau C. Bioinorganic chemistry of copper and zinc ions coordinated to amyloid-β peptide. Dalton Trans 2009:1080-94. [DOI: 10.1039/b813398k] [Citation(s) in RCA: 423] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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83
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Abstract
According to the amyloid pore hypothesis, pores formed by small oligomers of misfolded amyloidogenic proteins cause membrane leakage with the unregulated rapid influx of ions leading to cell death. Ultrastructurally, pores reconstituted in vitro have mainly been characterised so far, and the presence of in situ pores in the amyloid tissues has not yet been demonstrated. In this study, the presence of in situbeta amyloid (Abeta) pores was shown with high resolution transmission electron microscopy, in the neuronal cell membrane as well as in the membrane of mitochondria-like organelles in the brain with Alzheimer's disease. They are 16 nm wide and 11 nm long flat columnar structures made up of a single cylindrical layer (wall) of laterally associated Abeta protofilaments which surrounds a 10 nm wide opening or lumen. Protofilaments are the basic unit of the fibrils of all amyloid-forming proteins and peptides. Individual extracellular Abeta protofilaments were 2-3 nm wide straight tubular structures with helical wall formed by the tight coiling of 1 nm wide Abeta filaments. These in situ Abeta pores are similar but not identical to in vitro reconstituted Abeta pores.
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Affiliation(s)
- Sadayuki Inoue
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.
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84
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Meinhardt J, Sachse C, Hortschansky P, Grigorieff N, Fändrich M. Abeta(1-40) fibril polymorphism implies diverse interaction patterns in amyloid fibrils. J Mol Biol 2008; 386:869-77. [PMID: 19038266 PMCID: PMC6760659 DOI: 10.1016/j.jmb.2008.11.005] [Citation(s) in RCA: 244] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 11/04/2008] [Accepted: 11/05/2008] [Indexed: 10/21/2022]
Abstract
Amyloid fibrils characterize a diverse group of human diseases that includes Alzheimer's disease, Creutzfeldt-Jakob and type II diabetes. Alzheimer's amyloid fibrils consist of amyloid-beta (Abeta) peptide and occur in a range of structurally different fibril morphologies. The structural characteristics of 12 single Abeta(1-40) amyloid fibrils, all formed under the same solution conditions, were determined by electron cryo-microscopy and three-dimensional reconstruction. The majority of analyzed fibrils form a range of morphologies that show almost continuously altering structural properties. The observed fibril polymorphism implies that amyloid formation can lead, for the same polypeptide sequence, to many different patterns of inter- or intra-residue interactions. This property differs significantly from native, monomeric protein folding reactions that produce, for one protein sequence, only one ordered conformation and only one set of inter-residue interactions.
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Affiliation(s)
- Jessica Meinhardt
- Leibniz-Institut für Altersforschung (Fritz-Lipmann-Institut), Beutenbergstrabetae 11,D-07745 Jena, Germany
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85
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Bravo R, Arimon M, Valle-Delgado JJ, García R, Durany N, Castel S, Cruz M, Ventura S, Fernàndez-Busquets X. Sulfated Polysaccharides Promote the Assembly of Amyloid β1–42 Peptide into Stable Fibrils of Reduced Cytotoxicity. J Biol Chem 2008; 283:32471-83. [DOI: 10.1074/jbc.m709870200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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86
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Abstract
Interest in the problem of protein misfolding and aggregation has exploded in recent years for two reasons: (1) the sharp rise in the number and volume of therapeutic proteins produced commercially and (2) the recognition of the central role of protein aggregates in degenerative diseases. The systematic study of protein aggregation presents major challenges to both the experimentalist and the theoretician. Much of the work retains an empirical flavor due to the experimental complexities; the sensitivity of protein aggregation to the slightest change in protein amino acid composition, solvent properties, or protein concentration; and the lack of robust theoretical models of misfolding and aggregation. Novel experimental and computational approaches are being developed, and we anticipate substantial progress will be made in the near future. Several presentations describing the latest advances in protein misfolding and aggregation were given at the American Chemical Society meeting (BIOT division) held in September, 2006 in San Francisco.
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Affiliation(s)
- Regina M Murphy
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA.
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87
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Chi EY, Ege C, Winans A, Majewski J, Wu G, Kjaer K, Lee KYC. Lipid membrane templates the ordering and induces the fibrillogenesis of Alzheimer's disease amyloid-beta peptide. Proteins 2008; 72:1-24. [PMID: 18186465 DOI: 10.1002/prot.21887] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The lipid membrane has been shown to mediate the fibrillogenesis and toxicity of Alzheimer's disease (AD) amyloid-beta (Abeta) peptide. Electrostatic interactions between Abeta40 and the phospholipid headgroup have been found to control the association and insertion of monomeric Abeta into lipid monolayers, where Abeta exhibited enhanced interactions with charged lipids compared with zwitterionic lipids. To elucidate the molecular-scale structural details of Abeta-membrane association, we have used complementary X-ray and neutron scattering techniques (grazing-incidence X-ray diffraction, X-ray reflectivity, and neutron reflectivity) in this study to investigate in situ the association of Abeta with lipid monolayers composed of either the anionic lipid 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DPPG), the zwitterionic lipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), or the cationic lipid 1,2-dipalmitoyl 3-trimethylammonium propane (DPTAP) at the air-buffer interface. We found that the anionic lipid DPPG uniquely induced crystalline ordering of Abeta at the membrane surface that closely mimicked the beta-sheet structure in fibrils, revealing an intriguing templated ordering effect of DPPG on Abeta. Furthermore, incubating Abeta with lipid vesicles containing the anionic lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (POPG) induced the formation of amyloid fibrils, confirming that the templated ordering of Abeta at the membrane surface seeded fibril formation. This study provides a detailed molecular-scale characterization of the early structural fluctuation and assembly events that may trigger the misfolding and aggregation of Abeta in vivo. Our results implicate that the adsorption of Abeta to anionic lipids, which could become exposed to the outer membrane leaflet by cell injury, may serve as an in vivo mechanism of templated-aggregation and drive the pathogenesis of AD.
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Affiliation(s)
- Eva Y Chi
- Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, IL 60307, USA
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88
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Paired beta-sheet structure of an Abeta(1-40) amyloid fibril revealed by electron microscopy. Proc Natl Acad Sci U S A 2008; 105:7462-6. [PMID: 18483195 DOI: 10.1073/pnas.0712290105] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Alzheimer's disease is a neurodegenerative disorder that is characterized by the cerebral deposition of amyloid fibrils formed by Abeta peptide. Despite their prevalence in Alzheimer's and other neurodegenerative diseases, important details of the structure of amyloid fibrils remain unknown. Here, we present a three-dimensional structure of a mature amyloid fibril formed by Abeta(1-40) peptide, determined by electron cryomicroscopy at approximately 8-A resolution. The fibril consists of two protofilaments, each containing approximately 5-nm-long regions of beta-sheet structure. A local twofold symmetry within each region suggests that pairs of beta-sheets are formed from equivalent parts of two Abeta(1-40) peptides contained in each protofilament. The pairing occurs via tightly packed interfaces, reminiscent of recently reported steric zipper structures. However, unlike these previous structures, the beta-sheet pairing is observed within an amyloid fibril and includes significantly longer amino acid sequences.
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89
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Sharma S, Ding F, Dokholyan NV. Probing protein aggregation using discrete molecular dynamics. FRONT BIOSCI-LANDMRK 2008; 13:4795-808. [PMID: 18508545 DOI: 10.2741/3039] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Understanding the role of biomolecular dynamics in cellular processes leading to human diseases and the ability to rationally manipulate these processes is of fundamental importance in scientific research. The last decade has witnessed significant progress in probing biophysical behavior of proteins. However, we are still limited in understanding how changes in protein dynamics and inter-protein interactions occurring in short length- and time-scales lead to aberrations in their biological function. Bridging this gap in biology probed using computer simulations marks a challenging frontier in computational biology. Here we examine hypothesis-driven simplified protein models in conjunction with discrete molecular dynamics in the study of protein aggregation, implicated in series of neurodegenerative diseases, such as Alzheimer's and Huntington's diseases. Discrete molecular dynamics simulations of simplified protein models have emerged as a powerful methodology with its ability to bridge the gap in time and length scales from protein dynamics to aggregation, and provide an indispensable tool for probing protein aggregation.
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Affiliation(s)
- Shantanu Sharma
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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90
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Krysmann MJ, Castelletto V, Kelarakis A, Hamley IW, Hule RA, Pochan DJ. Self-Assembly and Hydrogelation of an Amyloid Peptide Fragment. Biochemistry 2008; 47:4597-605. [DOI: 10.1021/bi8000616] [Citation(s) in RCA: 244] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marta J. Krysmann
- Department of Chemistry, University of Reading, Reading RG6 6AD, United Kingdom, and Department of Materials Science and Engineering, Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19716
| | - Valeria Castelletto
- Department of Chemistry, University of Reading, Reading RG6 6AD, United Kingdom, and Department of Materials Science and Engineering, Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19716
| | - Antonios Kelarakis
- Department of Chemistry, University of Reading, Reading RG6 6AD, United Kingdom, and Department of Materials Science and Engineering, Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19716
| | - Ian W. Hamley
- Department of Chemistry, University of Reading, Reading RG6 6AD, United Kingdom, and Department of Materials Science and Engineering, Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19716
| | - Rohan A. Hule
- Department of Chemistry, University of Reading, Reading RG6 6AD, United Kingdom, and Department of Materials Science and Engineering, Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19716
| | - Darrin J. Pochan
- Department of Chemistry, University of Reading, Reading RG6 6AD, United Kingdom, and Department of Materials Science and Engineering, Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19716
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91
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Triguero L, Singh R, Prabhakar R. Molecular Dynamics Study To Investigate the Effect of Chemical Substitutions of Methionine 35 on the Secondary Structure of the Amyloid β (Aβ(1−42)) Monomer in Aqueous Solution. J Phys Chem B 2008; 112:2159-67. [DOI: 10.1021/jp0771872] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Luciano Triguero
- Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146
| | - Rajiv Singh
- Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146
| | - Rajeev Prabhakar
- Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146
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92
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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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93
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Noy D, Solomonov I, Sinkevich O, Arad T, Kjaer K, Sagi I. Zinc-amyloid beta interactions on a millisecond time-scale stabilize non-fibrillar Alzheimer-related species. J Am Chem Soc 2008; 130:1376-83. [PMID: 18179213 DOI: 10.1021/ja076282l] [Citation(s) in RCA: 180] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The role of zinc, an essential element for normal brain function, in the pathology of Alzheimer's disease (AD) is poorly understood. On one hand, physiological and genetic evidence from transgenic mouse models supports its pathogenic role in promoting the deposition of the amyloid beta-protein (Abeta) in senile plaques. On the other hand, levels of extracellular ("free") zinc in the brain, as inferred by the levels of zinc in cerebrospinal fluid, were found to be too low for inducing Abeta aggregation. Remarkably, the release of transient high local concentrations of zinc during rapid synaptic events was reported. The role of such free zinc pulses in promoting Abeta aggregation has never been established. Using a range of time-resolved structural and spectroscopic techniques, we found that zinc, when introduced in millisecond pulses of micromolar concentrations, immediately interacts with Abeta 1-40 and promotes its aggregation. These interactions specifically stabilize non-fibrillar pathogenic related aggregate forms and prevent the formation of Abeta fibrils (more benign species) presumably by interfering with the self-assembly process of Abeta. These in vitro results strongly suggest a significant role for zinc pulses in Abeta pathology. We further propose that by interfering with Abeta self-assembly, which leads to insoluble, non-pathological fibrillar forms, zinc stabilizes transient, harmful amyloid forms. This report argues that zinc represents a class of molecular pathogens that effectively perturb the self-assembly of benign Abeta fibrils, and stabilize harmful non-fibrillar forms.
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Affiliation(s)
- Dror Noy
- Structural Biology Department and Electron Microscopy Unit, Weizmann Institute of Science, Rehovot 76100, Israel
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94
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Harrison RS, Sharpe PC, Singh Y, Fairlie DP. Amyloid peptides and proteins in review. Rev Physiol Biochem Pharmacol 2007; 159:1-77. [PMID: 17846922 DOI: 10.1007/112_2007_0701] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Amyloids are filamentous protein deposits ranging in size from nanometres to microns and composed of aggregated peptide beta-sheets formed from parallel or anti-parallel alignments of peptide beta-strands. Amyloid-forming proteins have attracted a great deal of recent attention because of their association with over 30 diseases, notably neurodegenerative conditions like Alzheimer's, Huntington's, Parkinson's, Creutzfeldt-Jacob and prion disorders, but also systemic diseases such as amyotrophic lateral sclerosis (Lou Gehrig's disease) and type II diabetes. These diseases are all thought to involve important conformational changes in proteins, sometimes termed misfolding, that usually produce beta-sheet structures with a strong tendency to aggregate into water-insoluble fibrous polymers. Reasons for such conformational changes in vivo are still unclear. Intermediate aggregated state(s), rather than precipitated insoluble polymeric aggregates, have recently been implicated in cellular toxicity and may be the source of aberrant pathology in amyloid diseases. Numerous in vitro studies of short and medium length peptides that form amyloids have provided some clues to amyloid formation, with an alpha-helix to beta-sheet folding transition sometimes implicated as an intermediary step leading to amyloid formation. More recently, quite a few non-pathological amyloidogenic proteins have also been identified and physiological properties have been ascribed, challenging previous implications that amyloids were always disease causing. This article summarises a great deal of current knowledge on the occurrence, structure, folding pathways, chemistry and biology associated with amyloidogenic peptides and proteins and highlights some key factors that have been found to influence amyloidogenesis.
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Affiliation(s)
- R S Harrison
- Centre for Drug Design and Development, Institute for Molecular Bioscience, University of Queensland, QLD 4072, Brisbane, Australia
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95
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Cao M, Han Y, Wang J, Wang Y. Modulation of Fibrillogenesis of Amyloid β(1−40) Peptide with Cationic Gemini Surfactant. J Phys Chem B 2007; 111:13436-43. [DOI: 10.1021/jp075271b] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Meiwen Cao
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
| | - Yuchun Han
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
| | - Jinben Wang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
| | - Yilin Wang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
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96
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97
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Qin Z, Hu D, Han S, Hong DP, Fink AL. Role of different regions of alpha-synuclein in the assembly of fibrils. Biochemistry 2007; 46:13322-30. [PMID: 17963364 DOI: 10.1021/bi7014053] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Elucidating the details of the assembly of amyloid fibrils is a key step to understanding the mechanism of amyloid deposition diseases including Parkinson's disease. Although several models have been proposed, based on analyses of polypeptides and short peptides, a detailed understanding of the structure and mechanism of alpha-synuclein fibrillation remains elusive. In this study, we used trypsin and endoproteinase GluC to digest intact alpha-synuclein fibrils and to analyze the detailed morphology of the resultant fibrils/remnants. We also created three mutants of alpha-synuclein, in which the N-terminal and C-terminal regions were removed, both individually and in combination, and investigated the detailed morphology of the fibrils from these mutants. Our results indicate that the assembly of mature alpha-synuclein fibrils is hierarchical: protofilaments --> protofibrils --> mature fibrils. There is a core region of approximately 70 amino acids, from residues approximately 32 to 102, which comprises the beta-rich core of the protofilaments and fibrils. In contrast, the two terminal regions show no evidence of participating in the assembly of the protofilament core but play a key role in the interactions between the protofilaments, which is necessary for the fibril maturation.
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Affiliation(s)
- Zhijie Qin
- Department of Chemistry & Biochemistry, University of California, Santa Cruz, California 95064, USA
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98
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Abstract
Alzheimer's disease (AD) is the most prevalent neurodegenerative disease in the growing population of elderly people. A hallmark of AD is the accumulation of plaques in the brain of AD patients. The plaques predominantly consist of aggregates of amyloid-beta (Abeta), a peptide of 39-42 amino acids generated in vivo by specific, proteolytic cleavage of the amyloid precursor protein. There is a growing body of evidence that Abeta aggregates are ordered oligomers and the cause rather than a product of AD. The analysis of the assembly pathway of Abeta in vitro and biochemical characterization of Abeta deposits isolated from AD brains indicate that Abeta oligomerization occurs via distinct intermediates, including oligomers of 3-50 Abeta monomers, annular oligomers, protofibrils, fibrils and plaques. Of these, the most toxic species appear to be small Abeta oligomers. This article reviews the current knowledge of the mechanism of Abeta assembly in vivo and in vitro, as well as the influence of inherited amino acid replacements in Abeta and experimental conditions on Abeta aggregation. Challenges regarding the reproducible handling of the Abeta peptide for in vitro assembly studies are discussed.
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Affiliation(s)
- Verena H Finder
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
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99
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Groenning M, Norrman M, Flink JM, van de Weert M, Bukrinsky JT, Schluckebier G, Frokjaer S. Binding mode of Thioflavin T in insulin amyloid fibrils. J Struct Biol 2007; 159:483-97. [PMID: 17681791 DOI: 10.1016/j.jsb.2007.06.004] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 06/01/2007] [Accepted: 06/05/2007] [Indexed: 11/30/2022]
Abstract
Amyloid fibrils share various common structural features and their presence can be detected by Thioflavin T (ThT). In this paper, the binding mode of ThT to insulin amyloid fibrils was examined. Scatchard analysis and isothermal titration calorimetry (ITC) showed at least two binding site populations. The binding site population with the strongest binding was responsible for the characteristic ThT fluorescence. This binding had a capacity of about 0.1 moles of ThT bound per mole of insulin in fibril form. The binding capacity was unaffected by pH, but the affinity was lowest at low pH. Notably, presence of a third binding process prior to the other processes was suggested by ITC. Binding of ThT resulted in only minor changes in the fibril structure according to the X-ray diffraction patterns, where a slightly more dominant equatorial reflection at 16A relative to the intersheet distance of 11A was observed. No change in the interstrand distance of 4.8A was observed. On the basis of our results, we propose that ThT binds in cavities running parallel to the fibril axis, e.g., between the protofilaments forming the fibrils. Such cavities have been proposed previously in insulin fibrils and several other amyloid fibril models.
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Affiliation(s)
- Minna Groenning
- Department of Pharmaceutics and Analytical Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
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Groenning M, Olsen L, van de Weert M, Flink JM, Frokjaer S, Jørgensen FS. Study on the binding of Thioflavin T to β-sheet-rich and non-β-sheet cavities. J Struct Biol 2007; 158:358-69. [PMID: 17289401 DOI: 10.1016/j.jsb.2006.12.010] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 12/18/2006] [Accepted: 12/19/2006] [Indexed: 11/27/2022]
Abstract
Amyloid fibril formation plays a role in more than 20 diseases including Alzheimer's disease. In vitro detection of these fibrils is often performed using Thioflavin T (ThT), though the ThT binding mode is largely unknown. In the present study, spectral properties of ThT in binding environments representing beta-sheet-rich and non-beta-sheet cavities were examined. Acetylcholinesterase and gamma-cyclodextrin induced a characteristic ThT fluorescence similar to that with amyloid fibrils, whereas beta-cyclodextrin and the beta-sheet-rich transthyretin did not. The cavities of acetylcholinesterase and gamma-cyclodextrin were of similar diameter and only these cavities could accommodate two ThT ions according to molecular modelling. Binding stoichiometry studies also showed a possible binding of two ThT ions. Thus, the characteristic ThT fluorescence is induced in cavities with a diameter of 8-9A and a length able to accommodate the entire length of the ThT ion. The importance of a cavity diameter capable of binding two ThT ions, among others, indicates that an excimer formation is a plausible mechanism for the characteristic fluorescence. We propose a similar ThT binding mode in amyloid fibrils, where cavities of an appropriate size running parallel to the fibril axis have previously been proposed in several amyloid fibril models.
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Affiliation(s)
- Minna Groenning
- Department of Pharmaceutics and Analytical Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, 2100 Copenhagen, Denmark.
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