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Smardz P, Anila MM, Rogowski P, Li MS, Różycki B, Krupa P. A Practical Guide to All-Atom and Coarse-Grained Molecular Dynamics Simulations Using Amber and Gromacs: A Case Study of Disulfide-Bond Impact on the Intrinsically Disordered Amyloid Beta. Int J Mol Sci 2024; 25:6698. [PMID: 38928405 PMCID: PMC11204378 DOI: 10.3390/ijms25126698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 06/12/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024] Open
Abstract
Intrinsically disordered proteins (IDPs) pose challenges to conventional experimental techniques due to their large-scale conformational fluctuations and transient structural elements. This work presents computational methods for studying IDPs at various resolutions using the Amber and Gromacs packages with both all-atom (Amber ff19SB with the OPC water model) and coarse-grained (Martini 3 and SIRAH) approaches. The effectiveness of these methodologies is demonstrated by examining the monomeric form of amyloid-β (Aβ42), an IDP, with and without disulfide bonds at different resolutions. Our results clearly show that the addition of a disulfide bond decreases the β-content of Aβ42; however, it increases the tendency of the monomeric Aβ42 to form fibril-like conformations, explaining the various aggregation rates observed in experiments. Moreover, analysis of the monomeric Aβ42 compactness, secondary structure content, and comparison between calculated and experimental chemical shifts demonstrates that all three methods provide a reasonable choice to study IDPs; however, coarse-grained approaches may lack some atomistic details, such as secondary structure recognition, due to the simplifications used. In general, this study not only explains the role of disulfide bonds in Aβ42 but also provides a step-by-step protocol for setting up, conducting, and analyzing molecular dynamics (MD) simulations, which is adaptable for studying other biomacromolecules, including folded and disordered proteins and peptides.
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Affiliation(s)
| | | | | | | | | | - Pawel Krupa
- Institute of Physics Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland; (P.S.); (M.M.A.); (P.R.); (M.S.L.); (B.R.)
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2
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Pusara S. Molecular Dynamics Insights into the Aggregation Behavior of N-Terminal β-Lactoglobulin Peptides. Int J Mol Sci 2024; 25:4660. [PMID: 38731878 PMCID: PMC11083573 DOI: 10.3390/ijms25094660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/16/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024] Open
Abstract
β-lactoglobulin (BLG) forms amyloid-like aggregates at high temperatures, low pH, and low ionic strengths. At a pH below 2, BLG undergoes hydrolysis into peptides, with N-terminal peptides 1-33 and 1-52 being prone to fibrillization, forming amyloid-like fibrils. Due to their good mechanical properties, BLG amyloids demonstrate great potential for diverse applications, including biosensors, nanocomposites, and catalysts. Consequently, further studies are essential to comprehensively understand the factors governing the formation of BLG amyloid-like morphologies. In this study, all-atom molecular dynamics simulations were employed to explore the aggregation of N-terminal 1-33 and 1-52 BLG peptides under conditions of pH 2 and at 10 mM NaCl concentration. The simulations revealed that the peptides spontaneously assembled into aggregates of varying sizes. The aggregation process was enabled by the low charge of peptides and the presence of hydrophobic residues within them. As the peptides associated into aggregates, there was a concurrent increase in β-sheet structures and the establishment of hydrogen bonds, enhancing the stability of the aggregates. Notably, on average, 1-33 peptides formed larger aggregates compared to their 1-52 counterparts, while the latter exhibited a slightly higher content of β-sheets and higher cluster orderliness. The applied approach facilitated insights into the early stages of amyloid-like aggregation and molecular-level insight into the formation of β-sheets, which serve as nucleation points for further fibril growth.
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Affiliation(s)
- Srdjan Pusara
- Institute of Nanotechnology, Karlsruhe Institute of Technology KIT, Kaiserstraße 12, 76131 Karlsruhe, Germany
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3
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Okumura H. Perspective for Molecular Dynamics Simulation Studies of Amyloid-β Aggregates. J Phys Chem B 2023; 127:10931-10940. [PMID: 38109338 DOI: 10.1021/acs.jpcb.3c06051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
The cause of Alzheimer's disease is related to aggregates such as oligomers and amyloid fibrils consisting of amyloid-β (Aβ) peptides. Molecular dynamics (MD) simulation studies have been conducted to understand the molecular mechanism of the formation and disruption of Aβ aggregates. In this Perspective, the MD simulation studies are classified into four categories, focusing on the target systems: aggregation of Aβ peptides in bulk solution, Aβ aggregation at the interface, aggregation inhibitor against Aβ peptides, and nonequilibrium MD simulation of Aβ aggregates. MD simulation studies in these categories are first reviewed. Future perspectives in each category are then presented. Finally, the overall perspective is presented on how MD simulations of Aβ aggregates can be utilized for developing Alzheimer's disease treatment.
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Affiliation(s)
- Hisashi Okumura
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Okazaki, Aichi 444-8787, Japan
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4
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Lin TY, Ma YW, Tsai MY. Early-Stage Oligomerization of Prion-like Polypeptides Reveals the Molecular Mechanism of Amyloid-Disrupting Capacity by Proline Residues. J Phys Chem B 2023; 127:1074-1088. [PMID: 36705662 PMCID: PMC9924260 DOI: 10.1021/acs.jpcb.2c05463] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 12/09/2022] [Indexed: 01/28/2023]
Abstract
Proline cis/trans isomerization governs protein local conformational changes via its local mechanical rigidity. The amyloid-disrupting capacity of proline is widely acknowledged; however, the molecular mechanism is still not clear. To understand how proline residues in polypeptide chains influence amyloid propensity, we study several truncated sequences of the TDP-43 C-terminal region (287-322) and their triple proline variants (308PPP310). We use coarse-grained molecular simulation to study the time evolution of the process of aggregation in the early stages in an effective high-concentration condition (∼25 mM). This ensures the long time scales for protein association at laboratory concentrations. We use several experimentally determined structure templates as initial structures of monomer conformations. We carry out oligomer size analysis and cluster analysis, along with several structural measures, to characterize the size distributions of oligomers and their morphological/structural properties. We show that average oligomer size is not a good indicator of amyloid propensity. Structural order and/or morphological properties are better alternatives. We show that proline variants can efficiently maintain the formation of large "ordered" oligomers of shorter truncated sequences, i.e., 307-322. This "order" maintenance is weakened when using longer truncated sequences (i.e., 287-322), leading to the formation of "disordered" oligomers. From an energy trade-off perspective, if the entropic effect is weak (short sequence length), the shape-complementarity of proline variants effectively guides the oligomerization process to form "ordered" oligomer intermediates. This leads to a distinct aggregation pathway that promotes amyloid formation (on-pathway). Strong entropic effects (long sequence length), however, would cause the formation of "disordered" oligomers. This in turn will suppress amyloid formation (off-pathway). The proline shape-complementary effects provide a guided morphological restraint to facilitate the pathways of amyloid formation. Our study supports the importance of structure-based kinetic heterogeneity of prion-like sequence fragments in driving different aggregation pathways. This work sheds light on the role of morphological and structural order of early-stage oligomeric species in regulating amyloid-disrupting capacity by prolines.
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Affiliation(s)
- Tong-You Lin
- Department of Chemistry, Tamkang
University, New Taipei
City, Taiwan251301
| | - Yuan-Wei Ma
- Department of Chemistry, Tamkang
University, New Taipei
City, Taiwan251301
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5
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Molecular Dynamics Simulations of Protein Aggregation: Protocols for Simulation Setup and Analysis with Markov State Models and Transition Networks. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2340:235-279. [PMID: 35167078 DOI: 10.1007/978-1-0716-1546-1_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Protein disorder and aggregation play significant roles in the pathogenesis of numerous neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. The end products of the aggregation process in these diseases are highly structured amyloid fibrils. Though in most cases, small, soluble oligomers formed during amyloid aggregation are the toxic species. A full understanding of the physicochemical forces that drive protein aggregation is thus required if one aims for the rational design of drugs targeting the formation of amyloid oligomers. Among a multitude of biophysical and biochemical techniques that are employed for studying protein aggregation, molecular dynamics (MD) simulations at the atomic level provide the highest temporal and spatial resolution of this process, capturing key steps during the formation of amyloid oligomers. Here we provide a step-by-step guide for setting up, running, and analyzing MD simulations of aggregating peptides using GROMACS. For the analysis, we provide the scripts that were developed in our lab, which allow to determine the oligomer size and inter-peptide contacts that drive the aggregation process. Moreover, we explain and provide the tools to derive Markov state models and transition networks from MD data of peptide aggregation.
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6
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Yuan M, Tang X, Han W. Anatomy and Formation Mechanisms of Early Amyloid-β Oligomers with Lateral Branching: Graph Network Analysis on Large-Scale Simulations. Chem Sci 2022; 13:2649-2660. [PMID: 35356670 PMCID: PMC8890322 DOI: 10.1039/d1sc06337e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/08/2022] [Indexed: 11/29/2022] Open
Abstract
Oligomeric amyloid-β aggregates (AβOs) effectively trigger Alzheimer's disease-related toxicity, generating great interest in understanding their structures and formation mechanisms. However, AβOs are heterogeneous and transient, making their structure and formation difficult to study. Here, we performed graph network analysis of tens of microsecond massive simulations of early amyloid-β (Aβ) aggregations at near-atomic resolution to characterize AβO structures with sizes up to 20-mers. We found that AβOs exhibit highly curvilinear, irregular shapes with occasional lateral branches, consistent with recent cryo-electron tomography experiments. We also found that Aβ40 oligomers were more likely to develop branches than Aβ42 oligomers, explaining an experimental observation that only Aβ40 was trapped in network-like aggregates and exhibited slower fibrillization kinetics. Moreover, AβO architecture dissection revealed that their curvilinear appearance is related to the local packing geometries of neighboring peptides and that Aβ40's greater branching ability originates from specific C-terminal interactions at branching interfaces. Finally, we demonstrate that whether Aβ oligomerization causes oligomers to elongate or to branch depends on the sizes and shapes of colliding aggregates. Collectively, this study provides bottom-up structural information for understanding early Aβ aggregation and AβO toxicity. Graph network analysis on large-scale simulations uncovers the differential branching behaviours of large Aβ40 and Aβ42 oligomers.![]()
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Affiliation(s)
- Miao Yuan
- State Key Laboratory of Chemical Oncogenomics, Guangdong Provincial Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School Shenzhen 518055 China
| | - Xuan Tang
- State Key Laboratory of Chemical Oncogenomics, Guangdong Provincial Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School Shenzhen 518055 China
| | - Wei Han
- State Key Laboratory of Chemical Oncogenomics, Guangdong Provincial Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School Shenzhen 518055 China
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7
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Shi H, Wang L, Yao Z, Lee JY, Guo W. Role of the English (H6R) Mutation on the Structural Properties of Aβ40 and Aβ42 Owing to the Histidine Tautomeric Effect. ACS Chem Neurosci 2021; 12:2705-2711. [PMID: 34240598 DOI: 10.1021/acschemneuro.1c00355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
As an intrinsic origin cause, histidine behaviors play a critical role in protein misfolding processes. Generally, the English (H6R) mutation will disrupt H6 interactions. However, the structural properties of Aβ40 H6R and Aβ42 H6R under the complex influence of a histidine tautomeric effect and an H6R mutation remain unclear. Therefore, we performed a replica exchange molecular dynamics simulation to unveil such structural properties. Our result showed that the H6R substitute could promote the generation of β-sheet structures in comparison to the wild type. Three β-strand structure properties were observed in Aβ40 (rδδ), Aβ42 (rεε), Aβ42 (rεδ), and Aβ42 (rδδ) with β-sheet contents of 47.5%, 37.2%, 46.9%, and 38.6%, respectively, and the dominant conformational properties of Aβ40 (rδδ), Aβ42 (rεε), Aβ42 (rεδ), and Aβ42 (rδδ) had top conformational states of 86.0%, 73.2%, 67.0%, and 56.5%, respectively. Further analysis confirmed that R6 had different mechanisms for controlling the conformational features in Aβ40 H6R and Aβ42 H6R. In the Aβ40 systems, H14 H-bond networks played a critical role in controlling the structural properties. However, in the Aβ42 systems, R6 was more important because it was directly involved in the β-strand formation and maintained the β-sheet between the N-terminus and the central hydrophobic core region. Our current study helps to elucidate the histidine tautomeric behaviors in H6R mutations, which will present opportunities to understand the correlation between with/without H6 and the Aβ40/Aβ42 H6R misfolding mechanisms.
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Affiliation(s)
- Hu Shi
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China
- Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Lisha Wang
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China
| | - Zeshuai Yao
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China
| | - Jin Yong Lee
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, South Korea
| | - Wei Guo
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China
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8
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Wu M, Dorosh L, Schmitt-Ulms G, Wille H, Stepanova M. Aggregation of Aβ40/42 chains in the presence of cyclic neuropeptides investigated by molecular dynamics simulations. PLoS Comput Biol 2021; 17:e1008771. [PMID: 33711010 PMCID: PMC7990313 DOI: 10.1371/journal.pcbi.1008771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/24/2021] [Accepted: 02/04/2021] [Indexed: 11/18/2022] Open
Abstract
Alzheimer’s disease is associated with the formation of toxic aggregates of amyloid beta (Aβ) peptides. Despite tremendous efforts, our understanding of the molecular mechanisms of aggregation, as well as cofactors that might influence it, remains incomplete. The small cyclic neuropeptide somatostatin-14 (SST14) was recently found to be the most selectively enriched protein in human frontal lobe extracts that binds Aβ42 aggregates. Furthermore, SST14’s presence was also found to promote the formation of toxic Aβ42 oligomers in vitro. In order to elucidate how SST14 influences the onset of Aβ oligomerization, we performed all-atom molecular dynamics simulations of model mixtures of Aβ42 or Aβ40 peptides with SST14 molecules and analyzed the structure and dynamics of early-stage aggregates. For comparison we also analyzed the aggregation of Aβ42 in the presence of arginine vasopressin (AVP), a different cyclic neuropeptide. We observed the formation of self-assembled aggregates containing the Aβ chains and small cyclic peptides in all mixtures of Aβ42–SST14, Aβ42–AVP, and Aβ40–SST14. The Aβ42–SST14 mixtures were found to develop compact, dynamically stable, but small aggregates with the highest exposure of hydrophobic residues to the solvent. Differences in the morphology and dynamics of aggregates that comprise SST14 or AVP appear to reflect distinct (1) regions of the Aβ chains they interact with; (2) propensities to engage in hydrogen bonds with Aβ peptides; and (3) solvent exposures of hydrophilic and hydrophobic groups. The presence of SST14 was found to impede aggregation in the Aβ42–SST14 system despite a high hydrophobicity, producing a stronger “sticky surface” effect in the aggregates at the onset of Aβ42–SST14 oligomerization. Improper folding of proteins causes disorders known as protein misfolding diseases. Under normal conditions most proteins adopt particular folds, which allow them functioning properly. However, for reasons that are not yet fully understood, proteins may misfold and aggregate, forming deposits known as amyloid fibrils, which accumulate in the brain or other tissues. This process affects functioning of the nervous system, gradually causing loss of cognitive abilities. Alzheimer’s disease is one of the most common diseases from this group. A better understanding of the aggregation of peptides implicated in Alzheimer’s disease, known as amyloid beta (Aβ) peptides, may facilitate the development of treatments that ameliorate or prevent the disease. We use detailed molecular dynamics simulations to investigate the influence of somatostatin-14 (SST14), a cyclic neuropeptide that might be involved in the amyloidogenic aggregation of Aβ, on molecular processes occurring at the onset of Aβ aggregation. Results of these simulations explain how the presence of SST14 might alter pathways of aggregation of Aβ, shedding light upon the possible role of extrinsic factors in the aggregation at a molecular level.
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Affiliation(s)
- Min Wu
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
| | - Lyudmyla Dorosh
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
| | - Gerold Schmitt-Ulms
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Holger Wille
- Department of Biochemistry, University of Alberta, Edmonton, Canada
- Centre for Prions and Protein Folding Diseases, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Maria Stepanova
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
- * E-mail:
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9
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Cawood EE, Karamanos TK, Wilson AJ, Radford SE. Visualizing and trapping transient oligomers in amyloid assembly pathways. Biophys Chem 2021; 268:106505. [PMID: 33220582 PMCID: PMC8188297 DOI: 10.1016/j.bpc.2020.106505] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 10/29/2020] [Accepted: 11/01/2020] [Indexed: 12/31/2022]
Abstract
Oligomers which form during amyloid fibril assembly are considered to be key contributors towards amyloid disease. However, understanding how such intermediates form, their structure, and mechanisms of toxicity presents significant challenges due to their transient and heterogeneous nature. Here, we discuss two different strategies for addressing these challenges: use of (1) methods capable of detecting lowly-populated species within complex mixtures, such as NMR, single particle methods (including fluorescence and force spectroscopy), and mass spectrometry; and (2) chemical and biological tools to bias the amyloid energy landscape towards specific oligomeric states. While the former methods are well suited to following the kinetics of amyloid assembly and obtaining low-resolution structural information, the latter are capable of producing oligomer samples for high-resolution structural studies and inferring structure-toxicity relationships. Together, these different approaches should enable a clearer picture to be gained of the nature and role of oligomeric intermediates in amyloid formation and disease.
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Affiliation(s)
- Emma E Cawood
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK; Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew J Wilson
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, LS2 9JT, UK.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK.
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10
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Illig AM, Strodel B. Performance of Markov State Models and Transition Networks on Characterizing Amyloid Aggregation Pathways from MD Data. J Chem Theory Comput 2020; 16:7825-7839. [DOI: 10.1021/acs.jctc.0c00727] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Alexander-Maurice Illig
- Institute of Biological Information Processing: Structural Biochemistry (IBI-7), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Birgit Strodel
- Institute of Biological Information Processing: Structural Biochemistry (IBI-7), Forschungszentrum Jülich, 52428 Jülich, Germany
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
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11
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Paul S, Kumari K, Paul S. Molecular Insight into the Effects of Enhanced Hydrophobicity on Amyloid-like Aggregation. J Phys Chem B 2020; 124:10048-10061. [PMID: 33115237 DOI: 10.1021/acs.jpcb.0c06000] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Generally, hydrophobic amino acids provide hydrophobic interactions during peptide aggregation. However, besides the hydrophobic amino acids, some hydrophilic amino acids, such as glutamine, are also considered to be essential elements in many self-aggregating peptides. For example, huntingtin contains polyglutamine at its N-terminus and the yeast prion Sup35 protein has the GNNQQNY sequence, a peptide well-known for its ability for amyloid fibril formation. However, despite the frequent emergence of glutamine in self-assembling systems, the molecular mechanism of amyloid formation involving this unique amino acid has not been well documented. It is still not clear how this hydrophilic amino acid is responsible for the hydrophobic interaction in the self-association process. Therefore, in this study, we have carried out classical molecular dynamics simulations of the GNNQQNY peptide and its derivatives in pure water. We quantify the propensity for the formation of β-sheet conformation with an increasing glutamine number in the peptide sequence. In addition, we assess the importance of the hydrophobicity of the dimethanediyl group present in glutamine (as well as in glutamic acid) for the self-association of the peptides through nonpolar solvent medium simulations.
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Affiliation(s)
- Srijita Paul
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Komal Kumari
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Sandip Paul
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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12
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Sun Y, Ding F. αB-Crystallin Chaperone Inhibits Aβ Aggregation by Capping the β-Sheet-Rich Oligomers and Fibrils. J Phys Chem B 2020; 124:10138-10146. [PMID: 33119314 DOI: 10.1021/acs.jpcb.0c07256] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Inhibiting the cytotoxicity of amyloid aggregation by endogenous proteins is a promising strategy against degenerative amyloid diseases due to their intrinsically high biocompatibility and low immunogenicity. In this study, we investigated the inhibition mechanism of the structured core region of αB-crystallin (αBC) against Aβ fibrillization using discrete molecular dynamics simulations. Our computational results recapitulated the experimentally observed Aβ binding sites in αBC and suggested that αBC could bind to various Aβ aggregate species during the aggregation process-including monomers, dimers, and likely other high molecular weight oligomers, protofibrils, and fibrils-by capping the exposed β-sheet elongation surfaces. Thus, the nucleation of Aβ oligomers into fibrils and the fibril growth could be inhibited. Mechanistic insights obtained from our systematic computational studies may aid in the development of novel therapeutic strategies to modulate the aggregation of pathological, amyloidogenic protein in degenerative diseases.
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Affiliation(s)
- Yunxiang Sun
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, China.,Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, United States
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, United States
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13
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Rudajev V, Novotny J. The Role of Lipid Environment in Ganglioside GM1-Induced Amyloid β Aggregation. MEMBRANES 2020; 10:membranes10090226. [PMID: 32916822 PMCID: PMC7558528 DOI: 10.3390/membranes10090226] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 01/14/2023]
Abstract
Ganglioside GM1 is the most common brain ganglioside enriched in plasma membrane regions known as lipid rafts or membrane microdomains. GM1 participates in many modulatory and communication functions associated with the development, differentiation, and protection of neuronal tissue. It has, however, been demonstrated that GM1 plays a negative role in the pathophysiology of Alzheimer's disease (AD). The two features of AD are the formation of intracellular neurofibrillary bodies and the accumulation of extracellular amyloid β (Aβ). Aβ is a peptide characterized by intrinsic conformational flexibility. Depending on its partners, Aβ can adopt different spatial arrangements. GM1 has been shown to induce specific changes in the spatial organization of Aβ, which lead to enhanced peptide accumulation and deleterious effect especially on neuronal membranes containing clusters of this ganglioside. Changes in GM1 levels and distribution during the development of AD may contribute to the aggravation of the disease.
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14
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Pounot K, Chaaban H, Foderà V, Schirò G, Weik M, Seydel T. Tracking Internal and Global Diffusive Dynamics During Protein Aggregation by High-Resolution Neutron Spectroscopy. J Phys Chem Lett 2020; 11:6299-6304. [PMID: 32663030 DOI: 10.1021/acs.jpclett.0c01530] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Proteins can misfold and form either amorphous or organized aggregates with different morphologies and features. Aggregates of amyloid nature are pathological hallmarks in so-called protein conformational diseases, including Alzheimer's and Parkinson's. Evidence prevails that the transient early phases of the reaction determine the aggregate morphology and toxicity. As a consequence, real-time monitoring of protein aggregation is of utmost importance. Here, we employed time-resolved neutron backscattering spectroscopy to follow center-of-mass self-diffusion and nano- to picosecond internal dynamics of lysozyme during aggregation into a specific β-sheet rich superstructure, called particulates, formed at the isoelectric point of the protein. Particulate formation is found to be a one-step process, and protein internal dynamics, to remain unchanged during the entire aggregation process. The time-resolved neutron backscattering spectroscopy approach developed here, in combination with standard kinetics assays, provides a unifying framework in which dynamics and conformational transitions can be related to the different aggregation pathways.
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Affiliation(s)
- Kevin Pounot
- Université Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000 Grenoble, France
- Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, CS 20156, F-38042 Grenoble cedex 9, France
| | - Hussein Chaaban
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Vito Foderà
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Giorgio Schirò
- Université Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000 Grenoble, France
| | - Martin Weik
- Université Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000 Grenoble, France
| | - Tilo Seydel
- Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, CS 20156, F-38042 Grenoble cedex 9, France
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15
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Symmetry-breaking transitions in the early steps of protein self-assembly. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 49:175-191. [PMID: 32123956 DOI: 10.1007/s00249-020-01424-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/22/2020] [Accepted: 02/10/2020] [Indexed: 10/24/2022]
Abstract
Protein misfolding and subsequent self-association are complex, intertwined processes, resulting in development of a heterogeneous population of aggregates closely related to many chronic pathological conditions including Type 2 Diabetes Mellitus and Alzheimer's disease. To address this issue, here, we develop a theoretical model in the general framework of linear stability analysis. According to this model, self-assemblies of peptides with pronounced conformational flexibility may become, under particular conditions, unstable and spontaneously evolve toward an alternating array of partially ordered and disordered monomers. The predictions of the theory were verified by atomistic molecular dynamics (MD) simulations of islet amyloid polypeptide (IAPP) used as a paradigm of aggregation-prone polypeptides (proteins). Simulations of dimeric, tetrameric, and hexameric human-IAPP self-assemblies at physiological electrolyte concentration reveal an alternating distribution of the smallest domains (of the order of the peptide mean length) formed by partially ordered (mainly β-strands) and disordered (turns and coil) arrays. Periodicity disappears upon weakening of the inter-peptide binding, a result in line with the predictions of the theory. To further probe the general validity of our hypothesis, we extended the simulations to other peptides, the Aβ(1-40) amyloid peptide, and the ovine prion peptide as well as to other proteins (SOD1 dimer) that do not belong to the broad class of intrinsically disordered proteins. In all cases, the oligomeric aggregates show an alternate distribution of partially ordered and disordered monomers. We also carried out Surface Enhanced Raman Scattering (SERS) measurements of hIAPP as an experimental validation of both the theory and in silico simulations.
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16
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Liao Q. Enhanced sampling and free energy calculations for protein simulations. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 170:177-213. [PMID: 32145945 DOI: 10.1016/bs.pmbts.2020.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Molecular dynamics simulation is a powerful computational technique to study biomolecular systems, which complements experiments by providing insights into the structural dynamics relevant to biological functions at atomic scale. It can also be used to calculate the free energy landscapes of the conformational transitions to better understand the functions of the biomolecules. However, the sampling of biomolecular configurations is limited by the free energy barriers that need to be overcome, leading to considerable gaps between the timescales reached by MD simulation and those governing biological processes. To address this issue, many enhanced sampling methodologies have been developed to increase the sampling efficiency of molecular dynamics simulations and free energy calculations. Usually, enhanced sampling algorithms can be classified into methods based on collective variables (CV-based) and approaches which do not require predefined CVs (CV-free). In this chapter, the theoretical basis of free energy estimation is briefly reviewed first, followed by the reviews of the most common CV-based and CV-free methods including the presentation of some examples and recent developments. Finally, the combination of different enhanced sampling methods is discussed.
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Affiliation(s)
- Qinghua Liao
- Science for Life Laboratory, Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden.
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17
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Wille H, Dorosh L, Amidian S, Schmitt-Ulms G, Stepanova M. Combining molecular dynamics simulations and experimental analyses in protein misfolding. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020; 118:33-110. [PMID: 31928730 DOI: 10.1016/bs.apcsb.2019.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The fold of a protein determines its function and its misfolding can result in loss-of-function defects. In addition, for certain proteins their misfolding can lead to gain-of-function toxicities resulting in protein misfolding diseases such as Alzheimer's, Parkinson's, or the prion diseases. In all of these diseases one or more proteins misfold and aggregate into disease-specific assemblies, often in the form of fibrillar amyloid deposits. Most, if not all, protein misfolding diseases share a fundamental molecular mechanism that governs the misfolding and subsequent aggregation. A wide variety of experimental methods have contributed to our knowledge about misfolded protein aggregates, some of which are briefly described in this review. The misfolding mechanism itself is difficult to investigate, as the necessary timescale and resolution of the misfolding events often lie outside of the observable parameter space. Molecular dynamics simulations fill this gap by virtue of their intrinsic, molecular perspective and the step-by-step iterative process that forms the basis of the simulations. This review focuses on molecular dynamics simulations and how they combine with experimental analyses to provide detailed insights into protein misfolding and the ensuing diseases.
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Affiliation(s)
- Holger Wille
- Department of Biochemistry, University of Alberta, Edmonton, Canada; Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Lyudmyla Dorosh
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
| | - Sara Amidian
- Department of Biochemistry, University of Alberta, Edmonton, Canada; Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Canada
| | - Gerold Schmitt-Ulms
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Maria Stepanova
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
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18
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Nguyen PH, Sterpone F, Derreumaux P. Aggregation of disease-related peptides. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 170:435-460. [PMID: 32145950 DOI: 10.1016/bs.pmbts.2019.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Protein misfolding and aggregation of amyloid proteins is the fundamental cause of more than 20 diseases. Molecular mechanisms of the self-assembly and the formation of the toxic aggregates are still elusive. Computer simulations have been intensively used to study the aggregation of amyloid peptides of various amino acid lengths related to neurodegenerative diseases. We review atomistic and coarse-grained simulations of short amyloid peptides aimed at determining their transient oligomeric structures and the early and late aggregation steps.
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Affiliation(s)
- Phuong H Nguyen
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, Paris, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Fabio Sterpone
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, Paris, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Philippe Derreumaux
- Laboratory of Theoretical Chemistry, Ton Duc Thang University, Ho Chi Minh City, Vietnam; Faculty of Pharmacy, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
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19
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Shi H, Li H, Gong W, Gong R, Qian A, Lee JY, Guo W. Structural and Binding Properties on Aβ Mature Fibrils Due to the Histidine Tautomeric Effect. ACS Chem Neurosci 2019; 10:4612-4618. [PMID: 31566366 DOI: 10.1021/acschemneuro.9b00467] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Many studies have focused on histidine behaviors in misfolding diseases. However, histidine behaviors on mature fibrils are still unknown. In the current study, we investigated mature fibrils with various histidine states to understand the structural properties of the histidine tautomeric effect on mature fibrils. Our results show that substituting chain 1 with different histidine states affects Aβ structural properties in A2, D7-G9, H14-Q15, S26-N27, and G33-G37 regions. The binding free energies with substituted fibrils were influenced not only along the axial direction, but also between duplex fibrils. Our results suggest that substituted (εδδ) preferentially disturbed the stability among the current mature fibrils. Further, H-bonded network differences indicate that twisted morphologies in mature fibrils are derived from the position and orientation of the imidazole ring in histidines. Our current study helps to elucidate histidine behaviors on mature fibrils, which will present opportunities to understand the misfolding mechanisms.
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Affiliation(s)
| | - Hao Li
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, South Korea
| | | | | | | | - Jin Yong Lee
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, South Korea
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20
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Katyal N, Deep S. A computational approach to get insights into multiple faces of additives in modulation of protein aggregation pathways. Phys Chem Chem Phys 2019; 21:24269-24285. [PMID: 31670327 DOI: 10.1039/c9cp03763b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An enormous population worldwide is presently confronted with debilitating neurodegenerative diseases. The etiology of the disease is connected to protein aggregation and the events involved therein. Thus, a complete understanding of an inhibitor at different stages in the process is imperative for the formulation of a drug molecule. This review presents a detailed summary of the current status of different cosolvents. It further develops how the complex aggregation pathway can be simplified into three steps common to all proteins and the way computer simulations can be exploited to gain insights into the ways by which known inhibitors can affect all these stages. Computation of theoretical parameters in this regard and their correlation with experimental techniques is accentuated. In addition to providing an outline of the scope of different additives, this review showcases the way by which the problem of analyzing an effect of an additive can be addressed effectively via MD simulations.
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Affiliation(s)
- Nidhi Katyal
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016, Delhi, India.
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21
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Nguyen HL, Krupa P, Hai NM, Linh HQ, Li MS. Structure and Physicochemical Properties of the Aβ42 Tetramer: Multiscale Molecular Dynamics Simulations. J Phys Chem B 2019; 123:7253-7269. [DOI: 10.1021/acs.jpcb.9b04208] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Hoang Linh Nguyen
- Institute for Computational Science and Technology, SBI Building, Quang Trung Software
City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City 700000, Vietnam
- Biomedical Engineering Department, Ho Chi Minh City University of Technology-VNU HCM, 268 Ly Thuong Kiet Street, Distr. 10, Ho Chi Minh City 700000, Vietnam
| | - Pawel Krupa
- Institute of Physics Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - Nguyen Minh Hai
- Faculty of Physics and Engineering Physics, University of Science-VNU HCM, Ho Chi Minh City 700000, Vietnam
| | - Huynh Quang Linh
- Biomedical Engineering Department, Ho Chi Minh City University of Technology-VNU HCM, 268 Ly Thuong Kiet Street, Distr. 10, Ho Chi Minh City 700000, Vietnam
| | - Mai Suan Li
- Institute of Physics Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
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22
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Owen MC, Gnutt D, Gao M, Wärmländer SKTS, Jarvet J, Gräslund A, Winter R, Ebbinghaus S, Strodel B. Effects of in vivo conditions on amyloid aggregation. Chem Soc Rev 2019; 48:3946-3996. [PMID: 31192324 DOI: 10.1039/c8cs00034d] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
One of the grand challenges of biophysical chemistry is to understand the principles that govern protein misfolding and aggregation, which is a highly complex process that is sensitive to initial conditions, operates on a huge range of length- and timescales, and has products that range from protein dimers to macroscopic amyloid fibrils. Aberrant aggregation is associated with more than 25 diseases, which include Alzheimer's, Parkinson's, Huntington's, and type II diabetes. Amyloid aggregation has been extensively studied in the test tube, therefore under conditions that are far from physiological relevance. Hence, there is dire need to extend these investigations to in vivo conditions where amyloid formation is affected by a myriad of biochemical interactions. As a hallmark of neurodegenerative diseases, these interactions need to be understood in detail to develop novel therapeutic interventions, as millions of people globally suffer from neurodegenerative disorders and type II diabetes. The aim of this review is to document the progress in the research on amyloid formation from a physicochemical perspective with a special focus on the physiological factors influencing the aggregation of the amyloid-β peptide, the islet amyloid polypeptide, α-synuclein, and the hungingtin protein.
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Affiliation(s)
- Michael C Owen
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - David Gnutt
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany and Lead Discovery Wuppertal, Bayer AG, 42096 Wuppertal, Germany
| | - Mimi Gao
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany and Sanofi-Aventis Deutschland GmbH, R&D, Industriepark Höchst, 65926 Frankfurt, Germany
| | - Sebastian K T S Wärmländer
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Roland Winter
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, 42525 Jülich, Germany. and Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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23
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Yoon J, Kim Y, Park JW. Binary Structure of Amyloid Beta Oligomers Revealed by Dual Recognition Mapping. Anal Chem 2019; 91:8422-8428. [PMID: 31140786 DOI: 10.1021/acs.analchem.9b01316] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Amyloid beta (Aβ) oligomers are widely considered to be the causative agent of Alzheimer's disease (AD), a progressive neurodegenerative disorder. Determining the structure of oligomers is, therefore, important for understanding the disease and developing therapeutic agents; however, elucidating the structure has been proven difficult due to heterogeneity, noncrystallinity, and variability. Herein, we investigated homo- and hetero-oligomers of Aβ40 and Aβ42 using atomic force microscopy (AFM) and revealed characteristics of the molecular structure. By examining the surface of individual oligomers with sequential N- and C-terminus specific antibody-tethered tips, we simultaneously mapped the N- and C-terminus distributions and the elastic modulus. Interestingly, both the N- and C-termini of Aβ peptides were recognized on the oligomer surface, and the termini detected pixel regions exhibited a lower elastic modulus than silent pixel regions. These two types of regions were randomly distributed on the oligomer surface.
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Affiliation(s)
- Jihyun Yoon
- Department of Chemistry , Pohang University of Science and Technology , 77 Cheongam-Ro , Nam-Gu, Pohang 37673 , Republic of Korea
| | - Youngkyu Kim
- Department of Chemistry , Pohang University of Science and Technology , 77 Cheongam-Ro , Nam-Gu, Pohang 37673 , Republic of Korea
| | - Joon Won Park
- Department of Chemistry , Pohang University of Science and Technology , 77 Cheongam-Ro , Nam-Gu, Pohang 37673 , Republic of Korea
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24
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Hayward S, Kitao A. Multi-strand β-sheet of Alzheimer Aβ(1–40) folds to β-strip helix: implication for protofilament formation. J Biomol Struct Dyn 2019; 37:2143-2153. [DOI: 10.1080/07391102.2018.1477626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Steven Hayward
- D’Arcy Thompson Centre for Computational Biology, School of Computing Sciences, University of East Anglia, Norwich, UK
| | - Akio Kitao
- School of Life Science and Technology, Tokyo Institute of Technology, Ookayama, Meguro, Tokyo, Japan
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25
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Xing X, Zhao W, Hu D, Kang B, Shi H, Lee JY, Ai H. Tautomerization Effect of Histidines on Oligomer Aggregation of β-Amyloid(1-40/42) during the Early Stage: Tautomerism Hypothesis for Misfolding Protein Aggregation. ACS Chem Neurosci 2019; 10:2602-2608. [PMID: 30813720 DOI: 10.1021/acschemneuro.9b00094] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
As the intrinsic origin of the hypothesis for β-amyloid (Aβ) from Alzheimer's disease, histidine behaviors were found to play a crucial role in Aβ aggregation. To investigate the histidine behaviors during the early stage of aggregation, Aβ40/42 pentamers with different histidine isomer states were simulated at the atomic level. Results show that five Aβ40 (δδδ) and Aβ42 (εδδ) monomers can rapidly decrease the aggregation threshold, promote stable pentamer formation, and increase pentamer contents by 51.8% and 56.7%, respectively, as compared with the values of their wild-type (εεε) counterparts. Additionally, pentamers of Aβ40 (δδδ) and Aβ42 (εδδ) have different aggregation pathways and disassembly species, Tr+D and Te+M, during the growth of the pentamer. This work discloses the significance of histidine tautomerization in Aβ aggregation, implying a potential way to control Aβ aggregation and develop the assembly inhibitors.
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Affiliation(s)
- Xiaofeng Xing
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
| | - Wei Zhao
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
| | - Dingkun Hu
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
| | - Baotao Kang
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
| | - Hu Shi
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, P. R. China
| | - Jin Yong Lee
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, South Korea
| | - Hongqi Ai
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
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26
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Chiricotto M, Melchionna S, Derreumaux P, Sterpone F. Multiscale Aggregation of the Amyloid Aβ 16-22 Peptide: From Disordered Coagulation and Lateral Branching to Amorphous Prefibrils. J Phys Chem Lett 2019; 10:1594-1599. [PMID: 30892042 DOI: 10.1021/acs.jpclett.9b00423] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this work we investigate the multiscale dynamics of the aggregation process of an amyloid peptide, Aβ16-22. By performing massive coarse-grained simulations at the quasi-atomistic resolution and including hydrodynamic effects, we followed the formation and growth of a large elongated aggregate and its slow structuring. The elongation proceeds via a two-step nucleation mechanism with disordered aggregates formed initially and subsequently fusing to elongate the amorphous prefibril. A variety of coagulation events coexist, including lateral growth. The latter mechanism, sustained by long-range hydrodynamics correlations, actually can create a large branched structure spanning a few tens of nanometers. Our findings confirm the experimental hypothesis of a critical contribution of lateral growth to the amyloid aggregation kinetics and the capability of our model to sample critical structures like prefibril hosting annular pores.
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Affiliation(s)
- Mara Chiricotto
- Laboratoire de Biochimie Théorique, IBPC, CNRS UPR9080 , Univ. Paris Diderot, Sorbonne Paris Cité , 13 rue Pierre et Marie Curie , 75005 Paris , France
| | - Simone Melchionna
- ISC-CNR, Dipartimento di Fisica , Universita Sapienza , P.le A. Moro 5 , 00185 Rome , Italy
| | - Philippe Derreumaux
- Laboratoire de Biochimie Théorique, IBPC, CNRS UPR9080 , Univ. Paris Diderot, Sorbonne Paris Cité , 13 rue Pierre et Marie Curie , 75005 Paris , France
| | - Fabio Sterpone
- Laboratoire de Biochimie Théorique, IBPC, CNRS UPR9080 , Univ. Paris Diderot, Sorbonne Paris Cité , 13 rue Pierre et Marie Curie , 75005 Paris , France
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27
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Carballo-Pacheco M, Ismail AE, Strodel B. On the Applicability of Force Fields To Study the Aggregation of Amyloidogenic Peptides Using Molecular Dynamics Simulations. J Chem Theory Comput 2018; 14:6063-6075. [PMID: 30336669 DOI: 10.1021/acs.jctc.8b00579] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular dynamics simulations play an essential role in understanding biomolecular processes such as protein aggregation at temporal and spatial resolutions which are not attainable by experimental methods. For a correct modeling of protein aggregation, force fields must accurately represent molecular interactions. Here, we study the effect of five different force fields on the oligomer formation of Alzheimer's Aβ16-22 peptide and two of its mutants: Aβ16-22(F19V,F20V), which does not form fibrils, and Aβ16-22(F19L) which forms fibrils faster than the wild type. We observe that while oligomer formation kinetics depends strongly on the force field, structural properties, such as the most relevant protein-protein contacts, are similar between them. The oligomer formation kinetics obtained with different force fields differ more from each other than the kinetics between aggregating and nonaggregating peptides simulated with a single force field. We discuss the difficulties in comparing atomistic simulations of amyloid oligomer formation with experimental observables.
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Affiliation(s)
- Martín Carballo-Pacheco
- Institute of Complex Systems: Structural Biochemistry (ICS-6) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany.,AICES Graduate School , RWTH Aachen University , Schinkelstraße 2 , 52062 Aachen , Germany
| | - Ahmed E Ismail
- AICES Graduate School , RWTH Aachen University , Schinkelstraße 2 , 52062 Aachen , Germany.,Aachener Verfahrenstechnik, Faculty of Mechanical Engineering , RWTH Aachen University , Schinkelstraße 2 , 52062 Aachen , Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany.,Institute of Theoretical and Computational Chemistry , Heinrich Heine University Düsseldorf , Universitätstrasse 1 , 40225 Düsseldorf , Germany
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28
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Liao Q, Owen MC, Bali S, Barz B, Strodel B. Aβ under stress: the effects of acidosis, Cu 2+-binding, and oxidation on amyloid β-peptide dimers. Chem Commun (Camb) 2018; 54:7766-7769. [PMID: 29947363 DOI: 10.1039/c8cc02263a] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In light of the high affinity of Cu2+ for Alzheimer's Aβ1-42 and its ability to subsequently catalyze the formation of radicals, we examine the effects of Cu2+ binding, Aβ oxidation, and an acidic environment on the conformational dynamics of the smallest Aβ1-42 oligomer, the Aβ1-42 dimer. Transition networks calculated from Hamiltonian replica exchange molecular dynamics (H-REMD) simulations reveal that the decreased pH considerably increased the β-sheet content, whereas Cu2+ binding increased the exposed hydrophobic surface area, both of which can contribute to an increased oligomerization propensity and toxicity.
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Affiliation(s)
- Qinghua Liao
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany.
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29
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Zheng S, Shing KS, Sahimi M. Dynamics of proteins aggregation. II. Dynamic scaling in confined media. J Chem Phys 2018; 148:104305. [PMID: 29544316 DOI: 10.1063/1.5008543] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In this paper, the second in a series devoted to molecular modeling of protein aggregation, a mesoscale model of proteins together with extensive discontinuous molecular dynamics simulation is used to study the phenomenon in a confined medium. The medium, as a model of a crowded cellular environment, is represented by a spherical cavity, as well as cylindrical tubes with two aspect ratios. The aggregation process leads to the formation of β sheets and eventually fibrils, whose deposition on biological tissues is believed to be a major factor contributing to many neuro-degenerative diseases, such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis diseases. Several important properties of the aggregation process, including dynamic evolution of the total number of the aggregates, the mean aggregate size, and the number of peptides that contribute to the formation of the β sheets, have been computed. We show, similar to the unconfined media studied in Paper I [S. Zheng et al., J. Chem. Phys. 145, 134306 (2016)], that the computed properties follow dynamic scaling, characterized by power laws. The existence of such dynamic scaling in unconfined media was recently confirmed by experiments. The exponents that characterize the power-law dependence on time of the properties of the aggregation process in spherical cavities are shown to agree with those in unbounded fluids at the same protein density, while the exponents for aggregation in the cylindrical tubes exhibit sensitivity to the geometry of the system. The effects of the number of amino acids in the protein, as well as the size of the confined media, have also been studied. Similarities and differences between aggregation in confined and unconfined media are described, including the possibility of no fibril formation, if confinement is severe.
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Affiliation(s)
- Size Zheng
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211, USA
| | - Katherine S Shing
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211, USA
| | - Muhammad Sahimi
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211, USA
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30
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Majumdar BB, Ebbinghaus S, Heyden M. Macromolecular crowding effects in flexible polymer solutions. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2018. [DOI: 10.1142/s0219633618400060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Biological environments are often “crowded” due to high concentrations (300–400[Formula: see text]g/L) of macromolecules. Computational modeling approaches like Molecular Dynamics (MD), rigid-body Brownian Dynamics and Monte Carlo simulations have recently emerged, which allow to study the effects macromolecular crowding at a microscopic level and to provide complementary information to experiments. Here, we use a recently introduced multiple-conformation Monte Carlo (mcMC) approach in order to study the influence of intermolecular interactions on the structural equilibrium of flexible polyethylene glycol (PEG) polymers under self-crowding conditions. The large conformational space accessible to PEG polymers allows us to evaluate the general applicability of the mcMC approach, which describes the intramolecular degrees of freedom by a finite-size ensemble of discrete conformations. Despite the simplicity of the approach, we show that influences of intermolecular interactions on the intramolecular free energy surface can be described qualitatively using mcMC. By varying the magnitude of distinct terms in the intermolecular potential, we can further study the compensating effects of repulsive and nonspecific attractive intermolecular interactions, which favor compact and extended polymer states, respectively. We use our simulation results to derive an analytical model that describes the effects of intermolecular interactions on the stability of PEG polymer conformations as a function of the radius of gyration and the corresponding solvent accessible surface. We use this model to confirm the role of molecular surfaces for attractive interactions that can counteract excluded volume effects. Extrapolation of the model further allows for the analysis of scenarios that are not easily accessible to direct simulations as described here.
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Affiliation(s)
- Bibhab Bandhu Majumdar
- Theoretische Chemie, Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, Technical University, Braunschweig, Rebenring 56, 38106 Braunschweig, Germany
| | - Matthias Heyden
- School of Molecular Sciences, Arizona State University, 551 E. University Dr., Tempe, AZ 85281, USA
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31
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Jana AK, Batkulwar KB, Kulkarni MJ, Sengupta N. Glycation induces conformational changes in the amyloid-β peptide and enhances its aggregation propensity: molecular insights. Phys Chem Chem Phys 2018; 18:31446-31458. [PMID: 27827482 DOI: 10.1039/c6cp05041g] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The cytotoxicity of the amyloid beta (Aβ) peptide, implicated in the pathogenesis of Alzheimer's disease (AD), can be enhanced by its post-translational glycation, a series of non-enzymatic reactions with reducing sugars and reactive dicarbonyls. However, little is known about the underlying mechanisms that potentially enhance the cytotoxicity of the advanced glycation modified Aβ. In this work, fully atomistic molecular dynamics (MD) simulations are exploited to obtain direct molecular insights into the process of early Aβ self-assembly in the presence and absence of glycated lysine residues. Analyses of data exceeding cumulative timescales of 1 microsecond for each system reveal that glycation results in a stronger enthalpy of association between Aβ monomers and lower conformational entropy, in addition to a sharp overall increase in the beta-sheet content. Further analyses reveal that the enhanced interactions originate, in large part, due to markedly stronger, as well as new, inter-monomer salt bridging propensities in the glycated variety. Interestingly, these conformational and energetic effects are broadly reflected in preformed protofibrillar forms of Aβ small oligomers modified with glycation. Our combined results imply that glycation consolidates Aβ self-assembly regardless of its point of occurrence in the pathway. They provide a basis for further mechanistic studies and therapeutic endeavors that could potentially result in novel ways of combating AGE related AD progression.
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Affiliation(s)
- Asis K Jana
- Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India and Academy of Scientific and Innovative Research (AcSIR), New Delhi, India
| | - Kedar B Batkulwar
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, India and Biochemical Sciences Division, CSIR-National Chemical Laboratory, Pune 411008, India.
| | - Mahesh J Kulkarni
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, India and Biochemical Sciences Division, CSIR-National Chemical Laboratory, Pune 411008, India.
| | - Neelanjana Sengupta
- Dept. of Biological Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741 246, W. Bengal, India.
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32
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Katyal N, Deep S. Inhibition of GNNQQNY prion peptide aggregation by trehalose: a mechanistic view. Phys Chem Chem Phys 2018; 19:19120-19138. [PMID: 28702592 DOI: 10.1039/c7cp02912h] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Deposition of amyloid fibrils is the seminal event in the pathogenesis of numerous neurodegenerative diseases. The formation of this amyloid assembly is the manifestation of a cascade of structural transitions including toxic oligomer formation in the early stages of aggregation. Thus a viable therapeutic strategy involves the use of small molecular ligands to interfere with this assembly. In this perspective, we have explored the kinetics of aggregate formation of the fibril forming GNNQQNY peptide fragment from the yeast prion protein SUP35 using multiple all atom MD simulations with explicit solvent and provided mechanistic insights into the way trehalose, an experimentally known aggregation inhibitor, modulates the aggregation pathway. The results suggest that the assimilation process is impeded by different barriers at smaller and larger oligomeric sizes: the initial one being easily surpassed at higher temperatures and peptide concentrations. The kinetic profile demonstrates that trehalose delays the aggregation process by increasing both these activation barriers, specifically the latter one. It increases the sampling of small-sized aggregates that lack the beta sheet conformation. Analysis reveals that the barrier in the growth of larger stable oligomers causes the formation of multiple stable small oligomers which then fuse together bimolecularly. The PCA of 26 properties was carried out to deconvolute the events within the temporary lag phases, which suggested dynamism in lags involving an increase in interchain contacts and burial of SASA. The predominant growth route is monomer addition, which changes to condensation on account of a large number of depolymerisation events in the presence of trehalose. The favourable interaction of trehalose specifically with the sidechain of the peptide promotes crowding of trehalose molecules in its vicinity - the combination of both these factors imparts the observed behaviour. Furthermore, increasing trehalose concentration leads to faster expulsion of water molecules than interpeptide interactions. These expelled water molecules have larger translational movement, suggesting an entropy factor to favor the assembly process. Different conformations observed under this condition suggest the role of water molecules in guiding the morphology of the aggregates as well. A similar scenario exists on increasing peptide concentration.
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Affiliation(s)
- Nidhi Katyal
- Department of Chemistry, Indian Institute of Technology, Delhi, Hauzkhas, New Delhi, India.
| | - Shashank Deep
- Department of Chemistry, Indian Institute of Technology, Delhi, Hauzkhas, New Delhi, India.
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33
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Barz B, Liao Q, Strodel B. Pathways of Amyloid-β Aggregation Depend on Oligomer Shape. J Am Chem Soc 2017; 140:319-327. [PMID: 29235346 DOI: 10.1021/jacs.7b10343] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
One of the main research topics related to Alzheimer's disease is the aggregation of the amyloid-β peptide, which was shown to follow different pathways for the two major alloforms of the peptide, Aβ40 and the more toxic Aβ42. Experimental studies emphasized that oligomers of specific sizes appear in the early aggregation process in different quantities and might be the key toxic agents for each of the two alloforms. We use transition networks derived from all-atom molecular dynamics simulations to show that the oligomers leading to the type of oligomer distributions observed in experiments originate from compact conformations. Extended oligomers, on the other hand, contribute more to the production of larger aggregates thus driving the aggregation process. We further demonstrate that differences in the aggregation pathways of the two Aβ alloforms occur as early as during the dimer stage. The higher solvent-exposure of hydrophobic residues in Aβ42 oligomers contributes to the different aggregation pathways of both alloforms and also to the increased cytotoxicity of Aβ42.
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Affiliation(s)
- Bogdan Barz
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.,Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf , 40225 Düsseldorf, Germany
| | - Qinghua Liao
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.,Department of Cell and Molecular Biology, Uppsala University , S-75124 Uppsala, Sweden
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.,Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf , 40225 Düsseldorf, Germany
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34
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Zheng W, Tsai MY, Wolynes PG. Comparing the Aggregation Free Energy Landscapes of Amyloid Beta(1-42) and Amyloid Beta(1-40). J Am Chem Soc 2017; 139:16666-16676. [PMID: 29057654 PMCID: PMC5805378 DOI: 10.1021/jacs.7b08089] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Using a predictive coarse-grained protein force field, we compute and compare the free energy landscapes and relative stabilities of amyloid-β protein (1-42) and amyloid-β protein (1-40) in their monomeric and oligomeric forms up to the octamer. At the same concentration, the aggregation free energy profile of Aβ42 is more downhill, with a computed solubility that is about 10 times smaller than that of Aβ40. At a concentration of 40 μM, the clear free energy barrier between the pre-fibrillar tetramer form and the fibrillar pentamer in the Aβ40 aggregation landscape disappears for Aβ42, suggesting that the Aβ42 tetramer has a more diverse structural range. To further compare the landscapes, we develop a cluster analysis based on the structural similarity between configurations and use it to construct an oligomerization map that captures the paths of easy interconversion between different but structurally similar states of oligomers for both species. A taxonomy of the oligomer species based on β-sheet stacking topologies is proposed. The comparison of the two oligomerization maps highlights several key differences in the landscapes that can be attributed to the two additional C-terminal residues that Aβ40 lacks. In general, the two terminal residues strongly stabilize the oligomeric structures for Aβ42 relative to Aβ40, and greatly facilitate the conversion from pre-fibrillar trimers to fibrillar tetramers.
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Affiliation(s)
- Weihua Zheng
- Department of Chemistry, and Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Min-Yeh Tsai
- Department of Chemistry, and Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Peter G. Wolynes
- Department of Chemistry, and Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
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35
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Cao Y, Jiang X, Han W. Self-Assembly Pathways of β-Sheet-Rich Amyloid-β(1-40) Dimers: Markov State Model Analysis on Millisecond Hybrid-Resolution Simulations. J Chem Theory Comput 2017; 13:5731-5744. [PMID: 29019683 DOI: 10.1021/acs.jctc.7b00803] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Early oligomerization during amyloid-β (Aβ) aggregation is essential for Aβ neurotoxicity. Understanding how unstructured Aβs assemble into oligomers, especially those rich in β-sheets, is essential but remains challenging as the assembly process is too transient for experimental characterization and too slow for molecular dynamics simulations. So far, atomic simulations are limited only to studies of either oligomer structures or assembly pathways for short Aβ segments. To overcome the computational challenge, we combine in this study a hybrid-resolution model and adaptive sampling techniques to perform over 2.7 ms of simulations of formation of full-length Aβ40 dimers that are the earliest toxic oligomeric species. The Markov state model is further employed to characterize the transition pathways and associated kinetics. Our results show that for two major forms of β-sheet-rich structures reported experimentally, the corresponding assembly mechanisms are markedly different. Hairpin-containing structures are formed by direct binding of soluble Aβ in β-hairpin-like conformations. Formation of parallel, in-register structures resembling fibrils occurs ∼100-fold more slowly and involves a rapid encounter of Aβ in arbitrary conformations followed by a slow structural conversion. The structural conversion proceeds via diverse pathways but always requires transient unfolding of encounter complexes. We find that the transition kinetics could be affected differently by intra-/intermolecular interactions involving individual residues in a conformation-dependent manner. In particular, the interactions involving Aβ's N-terminal part promote the assembly into hairpin-containing structures but delay the formation of fibril-like structures, thus explaining puzzling observations reported previously regarding the roles of this region in the early assembly process.
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Affiliation(s)
- Yang Cao
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School , Shenzhen, 518055, China
| | - Xuehan Jiang
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School , Shenzhen, 518055, China
| | - Wei Han
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School , Shenzhen, 518055, China
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36
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Hu D, Zhao W, Zhu Y, Ai H, Kang B. Bead‐Level Characterization of Early‐Stage Amyloid β
42
Aggregates: Nuclei and Ionic Concentration Effects. Chemistry 2017; 23:16257-16273. [PMID: 28792099 DOI: 10.1002/chem.201702388] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Indexed: 01/12/2023]
Affiliation(s)
- Dingkun Hu
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials School of Chemistry and Chemical Engineering University of Jinan No. 336, West Road of Nan Xinzhuang Jinan Shandong 250022 P. R. China
| | - Wei Zhao
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials School of Chemistry and Chemical Engineering University of Jinan No. 336, West Road of Nan Xinzhuang Jinan Shandong 250022 P. R. China
| | - Yong Zhu
- Hospital in University of Jinan University of Jinan No. 336, West Road of Nan Xinzhuang Jinan Shandong 250022 P. R. China
| | - Hongqi Ai
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials School of Chemistry and Chemical Engineering University of Jinan No. 336, West Road of Nan Xinzhuang Jinan Shandong 250022 P. R. China
| | - Baotao Kang
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials School of Chemistry and Chemical Engineering University of Jinan No. 336, West Road of Nan Xinzhuang Jinan Shandong 250022 P. R. China
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37
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Chakraborty S, Das P. Emergence of Alternative Structures in Amyloid Beta 1-42 Monomeric Landscape by N-terminal Hexapeptide Amyloid Inhibitors. Sci Rep 2017; 7:9941. [PMID: 28855598 PMCID: PMC5577341 DOI: 10.1038/s41598-017-10212-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/04/2017] [Indexed: 02/01/2023] Open
Abstract
Alzheimer’s disease (AD) is characterized by deposition of amyloid beta (Aβ) peptides into senile plaques in the brain. While most familial mutations are associated with early-onset AD, recent studies report the AD-protective nature of two genetic human Aβ variants, i.e. A2T and A2V, in the heterozygous state. The mixture of A2V Aβ1-6 (Aβ6) hexapeptide and WT Aβ1–42 (Αβ42) is also found neuroprotective. Motivated by these findings, in this study we investigate the effects of WT, A2V, and A2T Aβ6 hexapeptide binding on the monomeric WT Aβ42 landscape. For this purpose, we have performed extensive atomistic Replica Exchange Molecular Dynamics simulations, elucidating preferential binding of Aβ42 with the A2V and A2T hexapeptides compared to WT Aβ6. A notable reorganization of the Aβ42 landscape is revealed due to hexapeptide association, as manifested by lowering of transient interactions between the central and C-terminal hydrophobic patches. Concurrently, Aβ6-bound Aβ42 monomer exhibits alternative structural features that are strongly dependent on the hexapeptide sequence. For example, a central helix is more frequently populated within the A2T-bound monomer, while A2V-bound Aβ42 is often enhanced in overall disorder. Taken together, the present simulations offer novel molecular insights onto the effect of the N-terminal hexapeptide binding on the Aβ42 monomer structure, which might help in explaining their reported amyloid inhibition properties.
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Affiliation(s)
| | - Payel Das
- IBM Thomas J. Watson Research Center, Yorktown Heights, NY, 10598, USA.
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38
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Patel S, Sasidhar YU, Chary KVR. Mechanism of Initiation, Association, and Formation of Amyloid Fibrils Modeled with the N-Terminal Peptide Fragment, IKYLEFIS, of Myoglobin G-Helix. J Phys Chem B 2017; 121:7536-7549. [PMID: 28707888 DOI: 10.1021/acs.jpcb.7b02205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Some peptides and proteins undergo self-aggregation under certain conditions, leading to amyloid fibrils formation, which is related to many disease conditions. It is important to understand such amyloid fibrils formation to provide mechanistic detail that governs the process. A predominantly α-helical myoglobin has been reported recently to readily form amyloid fibrils at a higher temperature, similar to its G-helix segment. Here, we have investigated the mechanism of amyloid fibrils formation by performing multiple long molecular dynamics simulations (27 μs) on the N-terminal segment of the G-helix of myoglobin. These simulations resulted in the formation of a single-layered tetrameric β-sheet with mixed parallel and antiparallel β-strands and this is the most common event irrespective of many different starting structures. Formation of the single-layered tetrameric β-sheet takes place following three distinctive pathways. The process of fibril initiation is dependent on temperature. Further, this study provides mechanistic insights into the formation of multilayered fibrilar structure, which could be applicable to a wider variety of peptides or proteins to understand the amyloidogenesis.
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Affiliation(s)
- Sunita Patel
- Tata Institute of Fundamental Research, Center for Interdisciplinary Sciences , Hyderabad 500075, India.,UM-DAE Centre for Excellence in Basic Sciences , Mumbai University Campus, Mumbai 400098, India
| | - Yellamraju U Sasidhar
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai 400076, India
| | - Kandala V R Chary
- Tata Institute of Fundamental Research, Center for Interdisciplinary Sciences , Hyderabad 500075, India.,Tata Institute of Fundamental Research , Mumbai 400005, India
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39
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Study of structural stability and damaging effect on membrane for four Aβ42 dimers. PLoS One 2017; 12:e0179147. [PMID: 28594887 PMCID: PMC5464659 DOI: 10.1371/journal.pone.0179147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 05/24/2017] [Indexed: 11/19/2022] Open
Abstract
Increasing evidence shows that Aβ oligomers are key pathogenic molecules in Alzheimer’s disease. Among Aβ oligomers, dimer is the smallest aggregate and toxic unit. Therefore, understanding its structural and dynamic properties is quite useful to prevent the formation and toxicity of the Aβ oligomers. In this study, we performed molecular dynamic simulations on four Aβ42 dimers, 2NCb, CNNC, NCNC and NCCN, within the hydrated DPPC membrane. Four Aβ42 dimers differ in the arrangements of two Aβ42 peptides. This study aims to investigate the impact of aggregation pattern of two Aβ peptides on the structural stability of the Aβ42 dimer and its disruption to the biological membrane. The MD results demonstrate that the NCCN, CNNC and NCNC have the larger structural fluctuation at the N-terminus of Aβ42 peptide, where the β-strand structure converts into the coil structure. The loss of the N-terminal β-strand further impairs the aggregate ability of Aβ42 dimer. In addition, inserting Aβ42 dimer into the membrane can considerably decrease the average APL of DPPC membrane. Moreover this decrease effect is largely dependent on the distance to the location of Aβ42 dimer and its secondary structure forms. Based on the results, the 2NCb is considered as a stable dimeric unit for aggregating the larger Aβ42 oligomer, and has a potent ability to disrupt the membrane.
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40
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Menon S, Sengupta N. Influence of Hyperglycemic Conditions on Self-Association of the Alzheimer's Amyloid β (Aβ 1-42) Peptide. ACS OMEGA 2017; 2:2134-2147. [PMID: 30023655 PMCID: PMC6044820 DOI: 10.1021/acsomega.7b00018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 05/08/2017] [Indexed: 06/08/2023]
Abstract
Clinical studies have identified a correlation between type-2 diabetes mellitus and cognitive decrements en route to the onset of Alzheimer's disease (AD). Recent studies have established that post-translational modifications of the amyloid β (Aβ) peptide occur under hyperglycemic conditions; particularly, the process of glycation exacerbates its neurotoxicity and accelerates AD progression. In view of the assertion that macromolecular crowding has an altering effect on protein self-assembly, it is crucial to characterize the effects of hyperglycemic conditions via crowding on Aβ self-assembly. Toward this purpose, fully atomistic molecular dynamics simulations were performed to study the effects of glucose crowding on Aβ dimerization, which is the smallest known neurotoxic species. The dimers formed in the glucose-crowded environment were found to have weaker associations as compared to that of those formed in water. Binding free energy calculations show that the reduced binding strength of the dimers can be mainly attributed to the overall weakening of the dispersion interactions correlated with substantial loss of interpeptide contacts in the hydrophobic patches of the Aβ units. Analysis to discern the differential solvation pattern in the glucose-crowded and pure water systems revealed that glucose molecules cluster around the protein, at a distance of 5-7 Å, which traps the water molecules in close association with the protein surface. This preferential exclusion of glucose molecules and resulting hydration of the Aβ peptides has a screening effect on the hydrophobic interactions, which in turn diminishes the binding strength of the resulting dimers. Our results imply that physical effects attributed to crowded hyperglycemic environments are incapable of solely promoting Aβ self-assembly, indicating that further mechanistic studies are required to provide insights into the self-assembly of post-translationally modified Aβ peptides, known to possess aggravated toxicity, under these conditions.
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Affiliation(s)
- Sneha Menon
- Physical
Chemistry Division, CSIR-National Chemical
Laboratory, Dr. Homi
Bhabha Road, Pune 411008, India
- Academy
of Scientific and Innovative Research (AcSIR), Training and Development Complex, CSIR Campus,
CSIR Road, Chennai 600113, India
| | - Neelanjana Sengupta
- Department
of Biological Sciences, Indian Institute
of Science Education and Research (IISER) Kolkata, Mohanpur 741246, West Bengal, India
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41
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Wolff M, Zhang-Haagen B, Decker C, Barz B, Schneider M, Biehl R, Radulescu A, Strodel B, Willbold D, Nagel-Steger L. Aβ42 pentamers/hexamers are the smallest detectable oligomers in solution. Sci Rep 2017; 7:2493. [PMID: 28559586 PMCID: PMC5449387 DOI: 10.1038/s41598-017-02370-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 04/11/2017] [Indexed: 12/14/2022] Open
Abstract
Amyloid β (Aβ) oligomers may play a decisive role in Alzheimer's disease related neurodegeneration, but their structural properties are poorly understood. In this report, sedimentation velocity centrifugation, small angle neutron scattering (SANS) and molecular modelling were used to identify the small oligomeric species formed by the 42 amino acid residue long isoform of Aβ (Aβ42) in solution, characterized by a sedimentation coefficient of 2.56 S, and a radius of gyration between 2 and 4 nm. The measured sedimentation coefficient is in close agreement with the sedimentation coefficient calculated for Aβ42 hexamers using MD simulations at µM concentration. To the best of our knowledge this is the first report detailing the Aβ42 oligomeric species by SANS measurements. Our results demonstrate that the smallest detectable species in solution are penta- to hexamers. No evidences for the presence of dimers, trimers or tetramers were found, although the existence of those Aβ42 oligomers at measurable quantities had been reported frequently.
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Affiliation(s)
- Martin Wolff
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
- Physikalische Biochemie, University Potsdam, 14476, Golm, Germany
| | - Bo Zhang-Haagen
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
- Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Christina Decker
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Bogdan Barz
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Mario Schneider
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Ralf Biehl
- Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Forschungszentrum Jülich, 52425, Jülich, Germany
- Jülich Centre for Neutron Science, Outstation at MLZ (JCNS-MLZ), Forschungszentrum Jülich, 85747, Garching, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science, Outstation at MLZ (JCNS-MLZ), Forschungszentrum Jülich, 85747, Garching, Germany
| | - Birgit Strodel
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Dieter Willbold
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Luitgard Nagel-Steger
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany.
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany.
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42
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Zheng S, Javidpour L, Shing KS, Sahimi M. Dynamics of proteins aggregation. I. Universal scaling in unbounded media. J Chem Phys 2017; 145:134306. [PMID: 27782447 DOI: 10.1063/1.4962837] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
It is well understood that in some cases proteins do not fold correctly and, depending on their environment, even properly-folded proteins change their conformation spontaneously, taking on a misfolded state that leads to protein aggregation and formation of large aggregates. An important factor that contributes to the aggregation is the interactions between the misfolded proteins. Depending on the aggregation environment, the aggregates may take on various shapes forming larger structures, such as protein plaques that are often toxic. Their deposition in tissues is a major contributing factor to many neuro-degenerative diseases, such as Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, and prion. This paper represents the first part in a series devoted to molecular simulation of protein aggregation. We use the PRIME, a meso-scale model of proteins, together with extensive discontinuous molecular dynamics simulation to study the aggregation process in an unbounded fluid system, as the first step toward MD simulation of the same phenomenon in crowded cellular environments. Various properties of the aggregates have been computed, including dynamic evolution of aggregate-size distribution, mean aggregate size, number of peptides that contribute to the formation of β sheets, number of various types of hydrogen bonds formed in the system, radius of gyration of the aggregates, and the aggregates' diffusivity. We show that many of such quantities follow dynamic scaling, similar to those for aggregation of colloidal clusters. In particular, at long times the mean aggregate size S(t) grows with time as, S(t) ∼ tz, where z is the dynamic exponent. To our knowledge, this is the first time that the qualitative similarity between aggregation of proteins and colloidal aggregates has been pointed out.
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Affiliation(s)
- Size Zheng
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211, USA
| | - Leili Javidpour
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran
| | - Katherine S Shing
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211, USA
| | - Muhammad Sahimi
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211, USA
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43
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Das P, Chacko AR, Belfort G. Alzheimer's Protective Cross-Interaction between Wild-Type and A2T Variants Alters Aβ 42 Dimer Structure. ACS Chem Neurosci 2017; 8:606-618. [PMID: 28292185 DOI: 10.1021/acschemneuro.6b00357] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Whole genome sequencing has recently revealed the protective effect of a single A2T mutation in heterozygous carriers against Alzheimer's disease (AD) and age-related cognitive decline. The impact of the protective cross-interaction between the wild-type (WT) and A2T variants on the dimer structure is therefore of high interest, as the Aβ dimers are the smallest known neurotoxic species. Toward this goal, extensive atomistic replica exchange molecular dynamics simulations of the solvated WT homo- and A2T hetero- Aβ1-42 dimers have been performed, resulting into a total of 51 μs of sampling for each system. Weakening of a set of transient, intrachain contacts formed between the central and C-terminal hydrophobic residues is observed in the heterodimeric system. The majority of the heterodimers with reduced interaction between central and C-terminal regions lack any significant secondary structure and display a weak interchain interface. Interestingly, the A2T N-terminus, particularly residue F4, is frequently engaged in tertiary and quaternary interactions with central and C-terminal hydrophobic residues in those distinct structures, leading to hydrophobic burial. This atypical involvement of the N-terminus within A2T heterodimer revealed in our simulations implies possible interference on Aβ42 aggregation and toxic oligomer formation, which is consistent with experiments. In conclusion, the present study provides detailed structural insights onto A2T Aβ42 heterodimer, which might provide molecular insights onto the AD protective effect of the A2T mutation in the heterozygous state.
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Affiliation(s)
- Payel Das
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Anita R. Chacko
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Georges Belfort
- Howard
P. Isermann Department of Chemical and Biological Engineering, and
Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, United States
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44
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Chiricotto M, Melchionna S, Derreumaux P, Sterpone F. Hydrodynamic effects on β-amyloid (16-22) peptide aggregation. J Chem Phys 2017; 145:035102. [PMID: 27448906 DOI: 10.1063/1.4958323] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Computer simulations based on simplified representations are routinely used to explore the early steps of amyloid aggregation. However, when protein models with implicit solvent are employed, these simulations miss the effect of solvent induced correlations on the aggregation kinetics and lifetimes of metastable states. In this work, we apply the multi-scale Lattice Boltzmann Molecular Dynamics technique (LBMD) to investigate the initial aggregation phases of the amyloid Aβ16-22 peptide. LBMD includes naturally hydrodynamic interactions (HIs) via a kinetic on-lattice representation of the fluid kinetics. The peptides are represented by the flexible OPEP coarse-grained force field. First, we have tuned the essential parameters that control the coupling between the molecular and fluid evolutions in order to reproduce the experimental diffusivity of elementary species. The method is then deployed to investigate the effect of HIs on the aggregation of 100 and 1000 Aβ16-22 peptides. We show that HIs clearly impact the aggregation process and the fluctuations of the oligomer sizes by favouring the fusion and exchange dynamics of oligomers between aggregates. HIs also guide the growth of the leading largest cluster. For the 100 Aβ16-22 peptide system, the simulation of ∼300 ns allowed us to observe the transition from ellipsoidal assemblies to an elongated and slightly twisted aggregate involving almost the totality of the peptides. For the 1000 Aβ16-22 peptides, a system of unprecedented size at quasi-atomistic resolution, we were able to explore a branched disordered fibril-like structure that has never been described by other computer simulations, but has been observed experimentally.
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Affiliation(s)
- Mara Chiricotto
- Laboratoire de Biochimie Théorique, IBPC, CNRS UPR9080, University Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Simone Melchionna
- CNR-ISC, Institute for Complex System, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Philippe Derreumaux
- Laboratoire de Biochimie Théorique, IBPC, CNRS UPR9080, University Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Fabio Sterpone
- Laboratoire de Biochimie Théorique, IBPC, CNRS UPR9080, University Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
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45
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Liao Q, Owen MC, Olubiyi OO, Barz B, Strodel B. Conformational Transitions of the Amyloid-β Peptide Upon Copper(II) Binding and pH Changes. Isr J Chem 2017. [DOI: 10.1002/ijch.201600108] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Qinghua Liao
- Institute of Complex Systems: Structural Biochemistry (ICS-6); Forschungszentrum Jülich GmbH; 52425 Jülich Germany
| | - Michael C. Owen
- Institute of Complex Systems: Structural Biochemistry (ICS-6); Forschungszentrum Jülich GmbH; 52425 Jülich Germany
| | - Olujide O. Olubiyi
- Department of Pharmacology and Therapeutics; College of Medicine and Health Sciences; Afe Babalola University; Nigeria
| | - Bogdan Barz
- Institute of Complex Systems: Structural Biochemistry (ICS-6); Forschungszentrum Jülich GmbH; 52425 Jülich Germany
- Institute of Theoretical and Computational Chemistry; Heinrich Heine University Düsseldorf; 40225 Düsseldorf Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6); Forschungszentrum Jülich GmbH; 52425 Jülich Germany
- Institute of Theoretical and Computational Chemistry; Heinrich Heine University Düsseldorf; 40225 Düsseldorf Germany
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46
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Buell AK. The Nucleation of Protein Aggregates - From Crystals to Amyloid Fibrils. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2017; 329:187-226. [DOI: 10.1016/bs.ircmb.2016.08.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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47
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Acharya S, Srivastava KR, Nagarajan S, Lapidus LJ. Monomer Dynamics of Alzheimer Peptides and Kinetic Control of Early Aggregation in Alzheimer's Disease. Chemphyschem 2016; 17:3470-3479. [PMID: 27490673 DOI: 10.1002/cphc.201600706] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Indexed: 12/20/2022]
Abstract
The rate of reconfiguration-or intramolecular diffusion-of monomeric Alzheimer (Aβ) peptides is measured and, under conditions that aggregation is more likely, peptide diffusion slows down significantly, which allows bimolecular associations to be initiated. By using the method of Trp-Cys contact quenching, the rate of reconfiguration is observed to be about five times faster for Aβ40 , which aggregates slowly, than that for Aβ42 , which aggregates quickly. Furthermore, the rate of reconfiguration for Aβ42 speeds up at higher pH, which slows aggregation, and in the presence of the aggregation inhibitor curcumin. The measured reconfiguration rates are able to predict the early aggregation behavior of the Aβ peptide and provide a kinetic basis for why Aβ42 is more prone to aggregation than Aβ40 , despite a difference of only two amino acids.
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Affiliation(s)
- Srabasti Acharya
- Department of Physics and Astronomy, Michigan State University, 567 Wilson Rd. Rm 4227, East Lansing, MI, 48824, USA
| | - Kinshuk R Srivastava
- Department of Physics and Astronomy, Michigan State University, 567 Wilson Rd. Rm 4227, East Lansing, MI, 48824, USA
| | - Sureshbabu Nagarajan
- Department of Physics and Astronomy, Michigan State University, 567 Wilson Rd. Rm 4227, East Lansing, MI, 48824, USA
| | - Lisa J Lapidus
- Department of Physics and Astronomy, Michigan State University, 567 Wilson Rd. Rm 4227, East Lansing, MI, 48824, USA.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
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48
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Barz B, Strodel B. Understanding Amyloid-β Oligomerization at the Molecular Level: The Role of the Fibril Surface. Chemistry 2016; 22:8768-72. [PMID: 27135646 DOI: 10.1002/chem.201601701] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Indexed: 12/11/2022]
Abstract
The aggregation of the amyloid β-peptide into fibrils is a complex process that involves mechanisms such as primary and secondary nucleation, fibril elongation and fibril fragmentation. Some of these processes generate neurotoxic Aβ oligomers, which are involved in the development of Alzheimer's disease. Recent experimental studies have emphasized the role of the fibril as a catalytic surface for the production of highly toxic oligomers during secondary nucleation. By using molecular dynamics simulations, we show that it is the hydrophobic fibril region that causes the structural changes required for catalyzing the formation of β-sheet-rich Aβ1-42 oligomers on the fibril surface. These results reveal, for the first time, the molecular basis of the secondary nucleation pathway.
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Affiliation(s)
- Bogdan Barz
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Birgit Strodel
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätstrasse 1, 40225, Düsseldorf, Germany. , .,Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich GmbH, 52425, Jülich, Germany. ,
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Nagel-Steger L, Owen MC, Strodel B. An Account of Amyloid Oligomers: Facts and Figures Obtained from Experiments and Simulations. Chembiochem 2016; 17:657-76. [PMID: 26910367 DOI: 10.1002/cbic.201500623] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 12/27/2022]
Abstract
The deposition of amyloid in brain tissue in the context of neurodegenerative diseases involves the formation of intermediate species-termed oligomers-of lower molecular mass and with structures that deviate from those of mature amyloid fibrils. Because these oligomers are thought to be primarily responsible for the subsequent disease pathogenesis, the elucidation of their structure is of enormous interest. Nevertheless, because of the high aggregation propensity and the polydispersity of oligomeric species formed by the proteins or peptides in question, the preparation of appropriate samples for high-resolution structural methods has proven to be rather difficult. This is why theoretical approaches have been of particular importance in gaining insights into possible oligomeric structures for some time. Only recently has it been possible to achieve some progress with regard to the experimentally based structural characterization of defined oligomeric species. Here we discuss how theory and experiment are used to determine oligomer structures and what can be done to improve the integration of the two disciplines.
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Affiliation(s)
- Luitgard Nagel-Steger
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany.,Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätstrasse 1, 40225, Düsseldorf, Germany
| | - Michael C Owen
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany. .,Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätstrasse 1, 40225, Düsseldorf, Germany.
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50
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Carballo-Pacheco M, Strodel B. Advances in the Simulation of Protein Aggregation at the Atomistic Scale. J Phys Chem B 2016; 120:2991-9. [PMID: 26965454 DOI: 10.1021/acs.jpcb.6b00059] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein aggregation into highly structured amyloid fibrils is associated with various diseases including Alzheimer's disease, Parkinson's disease, and type II diabetes. Amyloids can also have normal biological functions and, in the future, could be used as the basis for novel nanoscale materials. However, a full understanding of the physicochemical forces that drive protein aggregation is still lacking. Such understanding is crucial for the development of drugs that can effectively inhibit aberrant amyloid aggregation and for the directed design of functional amyloids. Atomistic simulations can help understand protein aggregation. In particular, atomistic simulations can be used to study the initial formation of toxic oligomers which are hard to characterize experimentally and to understand the difference in aggregation behavior between different amyloidogenic peptides. Here, we review the latest atomistic simulations of protein aggregation, concentrating on amyloidogenic protein fragments, and provide an outlook for the future in this field.
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Affiliation(s)
- Martín Carballo-Pacheco
- Institute of Complex Systems: Structural Biochemistry , Forschungszentrum Jülich, 52425 Jülich, Germany.,AICES Graduate School, RWTH Aachen University , Schinkelstraße 2, 52062 Aachen, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry , Forschungszentrum Jülich, 52425 Jülich, Germany.,Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf , Universitätsstrasse 1, 40225 Düsseldorf, Germany
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