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Ngo ST, Nguyen PH, Derreumaux P. Impact of A2T and D23N Mutations on Tetrameric Aβ42 Barrel within a Dipalmitoylphosphatidylcholine Lipid Bilayer Membrane by Replica Exchange Molecular Dynamics. J Phys Chem B 2020; 124:1175-1182. [DOI: 10.1021/acs.jpcb.9b11881] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Son Tung Ngo
- Laboratory of Theoretical and Computational Biophysics, Ton Duc Thang University, Ho Chi Minh City 33000, Vietnam
- Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City 33000, Vietnam
| | - Phuong H. Nguyen
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, F-75005 Paris, France
- Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Philippe Derreumaux
- Laboratory of Theoretical Chemistry, Ton Duc Thang University, Ho Chi Minh City 33000, Vietnam
- Faculty of Pharmacy, Ton Duc Thang University, Ho Chi Minh City 33000, Vietnam
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2
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Xi W, Hansmann UHE. Conversion between parallel and antiparallel β-sheets in wild-type and Iowa mutant Aβ 40 fibrils. J Chem Phys 2018; 148:045103. [PMID: 29390821 DOI: 10.1063/1.5016166] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Using a variant of Hamilton-replica-exchange, we study for wild type and Iowa mutant Aβ40 the conversion between fibrils with antiparallel β-sheets and such with parallel β-sheets. We show that wild type and mutant form distinct salt bridges that in turn stabilize different fibril organizations. The conversion between the two fibril forms leads to the release of small aggregates that in the Iowa mutant may shift the equilibrium from fibrils to more toxic oligomers.
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Affiliation(s)
- Wenhui Xi
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Ulrich H E Hansmann
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
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3
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Ngo ST, Thu Phung HT, Vu KB, Vu VV. Atomistic investigation of an Iowa Amyloid-β trimer in aqueous solution. RSC Adv 2018; 8:41705-41712. [PMID: 35558787 PMCID: PMC9091969 DOI: 10.1039/c8ra07615d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 12/04/2018] [Indexed: 11/21/2022] Open
Abstract
The self-assembly of Amyloid beta (Aβ) peptides are widely accepted to associate with Alzheimer's disease (AD) via several proposed mechanisms. Because Aβ oligomers exist in a complicated environment consisting of various forms of Aβ, including oligomers, protofibrils, and fibrils, their structure has not been well understood. The negatively charged residue D23 is one of the critical residues of the Aβ peptide as it is located in the central hydrophobic domain of the Aβ N-terminal and forms a salt-bridge D23-K28, which helps stabilize the loop domain. In the familial Iowa (D23N) mutant, the total net charge of Aβ oligomers decreases, resulting in the decrease of electrostatic repulsion between D23N Aβ monomers and thus the increase in their self-aggregation rate. In this work, the impact of the D23N mutation on 3Aβ11–40 trimer was characterized utilizing temperature replica exchange molecular dynamics (REMD) simulations. Our simulation reveals that D23N mutation significantly enhances the affinity between the constituting chains in the trimer, increases the β-content (especially in the sequence 21–23), and shifts the β-strand hydrophobic core from crossing arrangement to parallel arrangement, which is consistent with the increase in self-aggregation rate. Molecular docking indicates that the Aβ fibril-binding ligands bind to the D23N and WT forms at different poses. These compounds prefer to bind to the N-terminal β-strand of the D23N mutant trimer, while they mostly bind to the N-terminal loop region of the WT. It is important to take into account the difference in the binding of ligands to mutant and wild type Aβ peptides in designing efficient inhibitors for various types of AD. Amyloid beta peptide oligomers are believed to play key roles in Alzheimer's disease pathogenesis. D23N mutation significantly changes their structure and how they bind potential inhibitors.![]()
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Affiliation(s)
- Son Tung Ngo
- Laboratory of Theoretical and Computational Biophysics
- Ton Duc Thang University
- Ho Chi Minh City
- Vietnam
- Faculty of Applied Sciences
| | | | - Khanh B. Vu
- NTT Hi-Tech Institute
- Nguyen Tat Thanh University
- Ho Chi Minh City
- Vietnam
| | - Van V. Vu
- NTT Hi-Tech Institute
- Nguyen Tat Thanh University
- Ho Chi Minh City
- Vietnam
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4
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Xu L, Bhattacharya S, Thompson D. The fold preference and thermodynamic stability of α-synuclein fibrils is encoded in the non-amyloid-β component region. Phys Chem Chem Phys 2018; 20:4502-4512. [DOI: 10.1039/c7cp08321a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The strain-dependent synucleinopathies may be partially imprinted in the fold-dependent thermodynamic properties of non-amyloid-β component (NAC) fibrils.
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Affiliation(s)
- Liang Xu
- Department of Physics
- Bernal Institute
- University of Limerick
- Ireland
| | | | - Damien Thompson
- Department of Physics
- Bernal Institute
- University of Limerick
- Ireland
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5
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Guo Y, Hou J, Zhang X, Yang Y, Wang C. Stabilization Effect of Amino Acid Side Chains in Peptide Assemblies on Graphite Studied by Scanning Tunneling Microscopy. Chemphyschem 2017; 18:926-934. [DOI: 10.1002/cphc.201601353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Indexed: 01/14/2023]
Affiliation(s)
- Yuanyuan Guo
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience & CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology; No. 11 ZhongGuanCun BeiYiTiao 100190 Beijing P.R. China
| | - Jingfei Hou
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience & CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology; No. 11 ZhongGuanCun BeiYiTiao 100190 Beijing P.R. China
| | - Xuemei Zhang
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience & CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology; No. 11 ZhongGuanCun BeiYiTiao 100190 Beijing P.R. China
| | - Yanlian Yang
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience & CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology; No. 11 ZhongGuanCun BeiYiTiao 100190 Beijing P.R. China
| | - Chen Wang
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience & CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology; No. 11 ZhongGuanCun BeiYiTiao 100190 Beijing P.R. China
- University of the Chinese Academy of Sciences; No. 19A Yuquan Road, Shijingshan District 100049 Beijing P.R. China
- Center for Excellence in Brain Science and Intelligence Technology; Chinese Academy of Sciences; No. 320 Yue Yang Road 200031 Shanghai P.R. China
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6
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Lei J, Qi R, Wei G, Nussinov R, Ma B. Self-aggregation and coaggregation of the p53 core fragment with its aggregation gatekeeper variant. Phys Chem Chem Phys 2016; 18:8098-107. [PMID: 26923710 PMCID: PMC6456058 DOI: 10.1039/c5cp06538k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Recent studies suggested that p53 aggregation can lead to loss-of-function (LoF), dominant-negative (DN) and gain-of-function (GoF) effects, with adverse cancer consequences. The p53 aggregation-nucleating (251)ILTIITL(257) fragment is a key segment in wild-type p53 aggregation; however, an I254R mutation can prevent it. It was suggested that self-assembly of wild-type p53 and its cross-interaction with mutants differ from the classical amyloid nucleation-growth mechanism. Here, using replica exchange molecular dynamics (REMD) simulations, we studied the cross-interactions of this p53 core fragment and its aggregation rescue I254R mutant. We found that the core fragment displays strong aggregation propensity, whereas the gatekeeper I254R mutant tends to be disordered, consistent with experiments. Our cross-interaction results reveal that the wild-type p53 fragment promotes β-sheet formation of the I254R mutant by shifting the disordered mutant peptides into aggregating states. As a result, the system has similar oligomeric structures, inter-peptide interactions and free energy landscape as the wild type fragment does, revealing a prion-like process. We also found that in the cross-interaction system, the wild-type species has higher tendency to interact with the mutant than with itself. This phenomenon illustrates synergistic effects between the p53 (251)ILTIITL(257) fragment and the mutant resembling prion cross-species propagation, cautioning against exploiting it in drug discovery.
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Affiliation(s)
- Jiangtao Lei
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (MOE), and Department of Physics, Fudan University, Shanghai, P. R. China.
| | - Ruxi Qi
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (MOE), and Department of Physics, Fudan University, Shanghai, P. R. China.
| | - Guanghong Wei
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (MOE), and Department of Physics, Fudan University, Shanghai, P. R. China.
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA. and Sackler Inst. of Molecular Medicine Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA.
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Srivastava A, Balaji PV. Molecular events during the early stages of aggregation of GNNQQNY: An all atom MD simulation study of randomly dispersed peptides. J Struct Biol 2015; 192:376-391. [DOI: 10.1016/j.jsb.2015.09.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 09/26/2015] [Accepted: 09/30/2015] [Indexed: 12/11/2022]
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Han W, Schulten K. Fibril elongation by Aβ(17-42): kinetic network analysis of hybrid-resolution molecular dynamics simulations. J Am Chem Soc 2014; 136:12450-60. [PMID: 25134066 PMCID: PMC4156860 DOI: 10.1021/ja507002p] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
![]()
A critical step of β-amyloid
fibril formation is fibril elongation
in which amyloid-β monomers undergo structural transitions to
fibrillar structures upon their binding to fibril tips. The atomic
detail of the structural transitions remains poorly understood. Computational
characterization of the structural transitions is limited so far to
short Aβ segments (5–10 aa) owing to the long time scale
of Aβ fibril elongation. To overcome the computational time
scale limit, we combined a hybrid-resolution model with umbrella sampling
and replica exchange molecular dynamics and performed altogether ∼1.3
ms of molecular dynamics simulations of fibril elongation for Aβ17–42. Kinetic network analysis of biased simulations
resulted in a kinetic model that encompasses all Aβ segments
essential for fibril formation. The model not only reproduces key
properties of fibril elongation measured in experiments, including
Aβ binding affinity, activation enthalpy of Aβ structural
transitions and a large time scale gap (τlock/τdock = 103–104) between Aβ
binding and its structural transitions, but also reveals detailed
pathways involving structural transitions not seen before, namely,
fibril formation both in hydrophobic regions L17-A21 and G37-A42 preceding
fibril formation in hydrophilic region E22-A30. Moreover, the model
identifies as important kinetic intermediates strand–loop–strand
(SLS) structures of Aβ monomers, long suspected to be related
to fibril elongation. The kinetic model suggests further that fibril
elongation arises faster at the fibril tip with exposed L17-A21, rather
than at the other tip, explaining thereby unidirectional fibril growth
observed previously in experiments.
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Affiliation(s)
- Wei Han
- Beckman Institute, ‡Center for Biophysics and Computational Biology, and §Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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Srivastava A, Balaji PV. Interplay of sequence, topology and termini charge in determining the stability of the aggregates of GNNQQNY mutants: a molecular dynamics study. PLoS One 2014; 9:e96660. [PMID: 24817093 PMCID: PMC4015988 DOI: 10.1371/journal.pone.0096660] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 04/11/2014] [Indexed: 01/16/2023] Open
Abstract
This study explores the stabilities of single sheet parallel systems of three sequence variants of 1GNNQQNY7, N2D, N2S and N6D, with variations in aggregate size (5–8) and termini charge (charged or neutral). The aggregates were simulated at 300 and 330 K. These mutations decrease amyloid formation in the yeast prion protein Sup35. The present study finds that these mutations cause instability even in the peptide context. The protonation status of termini is found to be a key determinant of stabilities; other determinants are sequence, position of mutation and aggregate size. All systems with charged termini are unstable, whereas both stable and unstable systems are found when the termini are neutral. When termini are charged, the largest stable aggregate for the N2S and N6D systems has 3 to 4 peptides whereas N2D mutation supports oligomers of larger size (5-and 6-mers) as well. Mutation at 2nd position (N2S and N2D) results in fewer H-bonds at the mutated as well as neighboring (Gly1/Gln4) positions. However, no such effect is found if mutation is at 6th position (N6D). The effect of Asn→Asp mutation depends on the position and termini charge: it is more destabilizing at the 2nd position than at the 6th in case of neutral termini, however, the opposite is true in case of charged termini. Appearance of twist in stable systems and in smaller aggregates formed in unstable systems suggests that twist is integral to amyloid arrangement. Disorder, dissociation or rearrangement of peptides, disintegration or collapse of aggregates and formation of amorphous aggregates observed in these simulations are likely to occur during the early stages of aggregation also. The smaller aggregates formed due to such events have a variety of arrangements of peptides. This suggests polymorphic nature of oligomers and presence of a heterogeneous mixture of oligomers during early stages of aggregation.
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Affiliation(s)
- Alka Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Petety V. Balaji
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
- * E-mail:
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10
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Zhao JH, Liu HL, Liu YF, Lin HY, Fang HW, Ho Y, Tsai WB. Molecular dynamics simulations to investigate the aggregation behaviors of the Abeta(17-42) oligomers. J Biomol Struct Dyn 2013; 26:481-90. [PMID: 19108587 DOI: 10.1080/07391102.2009.10507263] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The amyloid beta-peptides (Abetas) are the main protein components of amyloid deposits in Alzheimer's disease (AD). Detailed knowledge of the structure and assembly dynamics of Abeta is important for the development of properly targeted AD therapeutics. So far, the process of the monomeric Abeta assembling into oligomeric fibrils and the mechanism underlying the aggregation process remain unclear. In this study, several molecular dynamics simulations were conducted to investigate the aggregation behaviors of the Abeta(17-42) oligomers associated with various numbers of monomers (dimer, trimer, tetramer, and pentamer). Our results showed that the structural stability of the Abeta(17-42) oligomers increases with increasing the number of monomer. We further demonstrated that the native hydrophobic contacts are positive correlated with the beta-sheet contents, indicating that hydrophobic interaction plays an important role in maintaining the structural stability of the Abeta(17-42) oligomers, particularly for those associated with more monomers. Our results also showed that the stability of the C-terminal hydrophobic segment 2 (residues 30-42) is higher than that of the N-terminal hydrophobic segment 1 (residues 17-21), suggesting that hydrophobic segment 2 may act as the nucleation site for aggregation. We further identified that Met35 residue initiates the hydrophobic interactions and that the intermolecular contact pairs, Gly33-Gly33 and Gly37-Gly37, form a stable "molecular notch", which may mediate the packing of the beta-sheet involving many other hydrophobic residues during the early stage of amyloid-like fibril formation.
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Affiliation(s)
- Jian-Hua Zhao
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1 Sec. 3 ZhongXiao E. Rd., Taipei, Taiwan 10608
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11
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Malavolta L, Nakaie CR. Comparative fibril formation of analogs corresponding to the (12-24) segment of the β-amyloid peptide. Neurol Sci 2011; 32:1123-7. [PMID: 21904866 DOI: 10.1007/s10072-011-0749-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 08/23/2011] [Indexed: 11/24/2022]
Abstract
The (1-42) β-amyloid peptide is a main component of the plaques found in the brain of patients suffering from the Alzheimer's disease. As the single substitution of Glu for Gln at position 22 of this peptide seems to be responsible for the manifestation of the more severe amyloidosis (Dutch-type), we decided to evaluate the aggregation characteristics of peptide analogs interchanging Glu and Gln residues at positions 22 and also 15 in the minor (12-24) (VHHQ(15)KLVFFAE(22)DV) fragment. The Q15Q22, E15E22, E15Q22 and the native Q15E22 were compared to the (1-42) β-amyloid peptide in terms of fibril or structured aggregates formation propensity. In contrast to a rather similar solubility data measured of all analogs, fluorescence and light scattering methods indicated that only Q15E22 and Q15Q22 displayed relevant fibril formation capacity. Conversely, E15E22 and E15Q22 were not capable of the formation of this type of structure thus suggesting a key role for the Q(15) residue in the unique aggregation characteristic of the β-amyloid peptide.
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Affiliation(s)
- Luciana Malavolta
- Instituto Israelita de Ensino e Pesquisa Albert Einstein, Av. Albert Einstein, 627, São Paulo, SP CEP 05652-000, Brazil
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12
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Velez-Vega C, Escobedo FA. Characterizing the structural behavior of selected Aβ-42 monomers with different solubilities. J Phys Chem B 2011; 115:4900-10. [PMID: 21486050 DOI: 10.1021/jp1086575] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The conformational behavior of the wild-type amyloid β-42 (Aβ-42) monomer and two of its mutants was explored via all-atom replica exchange molecular dynamics simulations in explicit solvent, to identify structural features that may promote or deter early-stage oligomerization. The markers used for this purpose indicate that while the three peptides are relatively flexible they have distinct preferential structures and degree of rigidity. In particular, we found that one mutant that remains in the monomeric state in experiments displays a characteristic N-terminal structure that significantly enhances its rigidity. This finding is consistent with various studies that have detected a reduction in oligomerization frequency and Aβ-related toxicity upon sequence-specific antibody or ligand binding to the N-terminal tail of wild-type monomers, likely leading to the stabilization of this region. In general, our results highlight a potential role of the N-terminal segment on Aβ oligomerization and give insights into specific interactions that may be responsible for promoting the pronounced structural changes observed upon introducing point mutations on the wild-type Aβ-42 peptide.
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Affiliation(s)
- Camilo Velez-Vega
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, USA
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13
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Mao Y, Shang Z, Imai Y, Hoshino T, Tero R, Tanaka M, Yamamoto N, Yanagisawa K, Urisu T. Surface-induced phase separation of a sphingomyelin/cholesterol/ganglioside GM1-planar bilayer on mica surfaces and microdomain molecular conformation that accelerates Abeta oligomerization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1090-9. [PMID: 20226163 DOI: 10.1016/j.bbamem.2010.03.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 02/07/2010] [Accepted: 03/01/2010] [Indexed: 12/29/2022]
Abstract
Ganglioside GM1 mediates the amyloid beta (Abeta) aggregation that is the hallmark of Alzheimer's disease (AD). To investigate how ganglioside-containing lipid bilayers interact with Abeta, we examined the interaction between Abeta40 and supported planar lipid bilayers (SPBs) on mica and SiO(2) substrates by using atomic force microscopy, fluorescence microscopy, and molecular dynamics computer simulations. These SPBs contained several compositions of sphingomyelin, cholesterol, and GM1 and were treated at physiological salt concentrations. Surprisingly high-speed Abeta aggregation of fibril formations occurred at all GM1 concentrations examined on the mica surface, but on the SiO(2) surface, only globular agglomerates formed and they formed slowly. At a GM1 concentration of 20mol%, unique triangular regions formed on the mica surface and the rapidly formed Abeta aggregations were observed only outside these regions. We have found that some unique surface-induced phase separations are induced by the GM1 clustering effects and the strong interactions between the GM1 head group and the water layer adsorbed in the ditrigonal cavities on the mica surface. The speed of Abeta40 aggregation and the shape of the agglomerates depend on the molecular conformation of GM1, which varies depending on the substrate materials. We identified the conformation that significantly accelerates Abeta40 aggregation, and we think that the detailed knowledge about the GM1 molecular conformation obtained in this work will be useful to those investigating Abeta-GM1 interactions.
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Affiliation(s)
- Yanli Mao
- Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan
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14
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Xu W, Ping J, Li W, Mu Y. Assembly dynamics of two-beta sheets revealed by molecular dynamics simulations. J Chem Phys 2009; 130:164709. [PMID: 19405618 DOI: 10.1063/1.3123532] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The assembly dynamics of two beta sheets with different initial separation distances are explored by multiple all-atom molecular dynamics simulations with the presence of explicit water solvent. The beta sheet is composed of seven identical peptides in an antiparallel fashion. The peptide sequence is the 20-29 segment of human Islet amyloid polypeptide. Our simulations show that the assembly occurs not only in the lateral direction but also along the longitudinal direction, which provides a new insight into the assembly pathway at the early stage of fibril elongation. Based on Poisson-Boltzmann free energy analysis and quasiharmonic configuration entropy estimation, the entropic contribution is found to play an important role in the longitudinal assembly. Moreover, a possible oligomeric state with cyclic form is suggested based on one assembly model found in the simulations, illustrating the polymorphic nature of aggregation of the amyloidogenic peptide.
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Affiliation(s)
- Weixin Xu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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15
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Microscopic factors that control beta-sheet registry in amyloid fibrils formed by fragment 11-25 of amyloid beta peptide: insights from computer simulations. J Mol Biol 2009; 389:921-37. [PMID: 19414017 DOI: 10.1016/j.jmb.2009.04.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 04/27/2009] [Accepted: 04/28/2009] [Indexed: 01/21/2023]
Abstract
Short fragments of amyloidogenic proteins are widely used as model systems in studies of amyloid formation. Fragment 11-25 of the amyloid beta protein involved in Alzheimer's disease (Abeta11-25) was recently shown to form amyloid fibrils composed of anti-parallel beta-sheets. Interestingly, fibrils grown under neutral and acidic conditions were seen to possess different registries of their inter-beta-strand hydrogen bonds. In an effort to explain the microscopic origin of this pH dependence, we studied Abeta11-25 fibrils using methods of theoretical modeling. Several structural models were built for fibrils at low and neutral pH levels and these were examined in short molecular dynamics simulations in explicit water. The models that displayed the lowest free energy, as estimated using an implicit solvent model, were selected as representative of the true fibrillar structure. It was shown that the registry of these models agrees well with the experimental results. At neutral pH, the main contribution to the free energy difference between the two registries comes from the electrostatic interactions. The charge group of the carboxy terminus makes a large contribution to these interactions and thus appears to have a critical role in determining the registry.
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Kelley NW, Vishal V, Krafft GA, Pande VS. Simulating oligomerization at experimental concentrations and long timescales: A Markov state model approach. J Chem Phys 2008; 129:214707. [PMID: 19063575 PMCID: PMC2674793 DOI: 10.1063/1.3010881] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 10/10/2008] [Indexed: 11/14/2022] Open
Abstract
Here, we present a novel computational approach for describing the formation of oligomeric assemblies at experimental concentrations and timescales. We propose an extension to the Markovian state model approach, where one includes low concentration oligomeric states analytically. This allows simulation on long timescales (seconds timescale) and at arbitrarily low concentrations (e.g., the micromolar concentrations found in experiments), while still using an all-atom model for protein and solvent. As a proof of concept, we apply this methodology to the oligomerization of an Abeta peptide fragment (Abeta(21-43)). Abeta oligomers are now widely recognized as the primary neurotoxic structures leading to Alzheimer's disease. Our computational methods predict that Abeta trimers form at micromolar concentrations in 10 ms, while tetramers form 1000 times more slowly. Moreover, the simulation results predict specific intermonomer contacts present in the oligomer ensemble as well as putative structures for small molecular weight oligomers. Based on our simulations and statistical models, we propose a novel mutation to stabilize the trimeric form of Abeta in an experimentally verifiable manner.
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Affiliation(s)
- Nicholas W Kelley
- Department of Biophysics, Stanford University, Stanford, California 94305, USA
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Hung A, Griffin MDW, Howlett GJ, Yarovsky I. Effects of oxidation, pH and lipids on amyloidogenic peptide structure: implications for fibril formation? EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 38:99-110. [PMID: 18769912 DOI: 10.1007/s00249-008-0363-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 08/01/2008] [Accepted: 08/04/2008] [Indexed: 10/21/2022]
Abstract
We have performed experimental and computational studies to investigate the influences of phospholipids, methionine oxidation and acidic pH on amyloid fibril formation by a peptide derived from human apolipoprotein C-II (apoC-II), a known component of proteinaceous atherosclerotic plaques. Fibril growth monitored by thioflavin T fluorescence revealed inhibition under lipid-rich and oxidising conditions. We subsequently performed fully-solvated atomistic molecular dynamics (MD) simulations of the peptide monomer to study its conformations under both fibril favouring (neutral and low pH) and inhibiting (lipid-rich and oxidising) conditions. Examination of the chain topology, backbone hydrogen-bonding patterns and aromatic sidechain orientations of the peptide under different conditions reveals that, while the peptide adopts similar structures under the fibril-favouring conditions, significantly different structures are obtained under fibril-disruptive conditions. Based on our results, we advance hypotheses for the roles of peptide conformation on aggregation and fibrillisation propensities.
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Affiliation(s)
- Andrew Hung
- School of Applied Sciences, RMIT University, GPO Box 2476V, Melbourne, VIC 3001, Australia
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Zheng J, Ma B, Chang Y, Nussinov R. Molecular dynamics simulations of Alzheimer Abeta40 elongation and lateral association. FRONT BIOSCI-LANDMRK 2008; 13:3919-30. [PMID: 18508486 DOI: 10.2741/2980] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Amyloid-beta (Abeta) peptides can elongate in the fibril axis and associate in the lateral direction. We present detailed atomic Abeta models with different in-register intermolecular beta-sheet-beta-sheet associations. We probe structural stability, conformational dynamics, and association force of Abeta oligomers with various sizes and structures for both wild-type and mutated sequences using molecular dynamics (MD) simulations. MD simulations show that an Abeta oligomer that is laterally associated through the C-terminal-C-terminal interface is energetically more favorable than other oligomers with the N-terminal-N-terminal and C-terminal-N-terminal interfaces. We further develop a simple numerical model to describe the kinetics of Abeta aggregation process by considering fibril elongation and lateral association using a Monte Carlo algorithm. Kinetic data suggest that fibril elongation and lateral association are mutually competitive. Single-point mutations of Glu22 or Met35 at the interfaces have profound negative effects on intermolecular beta-sheet-beta-sheet association. These disease-related mutants (E22K, E22Q, and M35O) display more flexible structures, weaker lateral association, and stronger elongation tendencies than the wild type, suggesting that amyloid oligomerization and neurotoxicity might be linked to fibril longitudinal growth.
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Affiliation(s)
- Jie Zheng
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, USA.
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19
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Jang S, Shin S. Computational study on the structural diversity of amyloid Beta Peptide (abeta(10-35)) oligomers. J Phys Chem B 2008; 112:3479-84. [PMID: 18303879 DOI: 10.1021/jp076450w] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We studied the oligomerization of Alzheimer amyloid beta peptide (Abeta) using a replica exchange molecular dynamics (REMD) simulation. The simulation was performed with Abeta(10-35) dimers, trimers, and tetramers. Extensive REMD simulations illustrated several possible oligomer conformations. As the size of the oligomer increased from a dimer to a tetramer, the number of possible configurations was reduced. We identified all the possible conformations for each oligomer and characterized their temperature dependence. It was found that the detailed structures of the oligomers, which may act as folding intermediates, are highly sensitive to the parameters of the simulation environment such as temperature and concentration. Structural diversities of Abeta oligomers suggest multiple pathways of the aggregation process.
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Affiliation(s)
- Soonmin Jang
- School of Chemistry, Seoul National University, Seoul 151-747, Korea
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