51
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Nguyen PH, Ramamoorthy A, Sahoo BR, Zheng J, Faller P, Straub JE, Dominguez L, Shea JE, Dokholyan NV, De Simone A, Ma B, Nussinov R, Najafi S, Ngo ST, Loquet A, Chiricotto M, Ganguly P, McCarty J, Li MS, Hall C, Wang Y, Miller Y, Melchionna S, Habenstein B, Timr S, Chen J, Hnath B, Strodel B, Kayed R, Lesné S, Wei G, Sterpone F, Doig AJ, Derreumaux P. Amyloid Oligomers: A Joint Experimental/Computational Perspective on Alzheimer's Disease, Parkinson's Disease, Type II Diabetes, and Amyotrophic Lateral Sclerosis. Chem Rev 2021; 121:2545-2647. [PMID: 33543942 PMCID: PMC8836097 DOI: 10.1021/acs.chemrev.0c01122] [Citation(s) in RCA: 368] [Impact Index Per Article: 122.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein misfolding and aggregation is observed in many amyloidogenic diseases affecting either the central nervous system or a variety of peripheral tissues. Structural and dynamic characterization of all species along the pathways from monomers to fibrils is challenging by experimental and computational means because they involve intrinsically disordered proteins in most diseases. Yet understanding how amyloid species become toxic is the challenge in developing a treatment for these diseases. Here we review what computer, in vitro, in vivo, and pharmacological experiments tell us about the accumulation and deposition of the oligomers of the (Aβ, tau), α-synuclein, IAPP, and superoxide dismutase 1 proteins, which have been the mainstream concept underlying Alzheimer's disease (AD), Parkinson's disease (PD), type II diabetes (T2D), and amyotrophic lateral sclerosis (ALS) research, respectively, for many years.
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Affiliation(s)
- Phuong H Nguyen
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Bikash R Sahoo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jie Zheng
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Peter Faller
- Institut de Chimie, UMR 7177, CNRS-Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg, France
| | - John E Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Laura Dominguez
- Facultad de Química, Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Nikolay V Dokholyan
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
- Department of Chemistry, and Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, London SW7 2AZ, U.K
- Molecular Biology, University of Naples Federico II, Naples 80138, Italy
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Saeed Najafi
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Son Tung Ngo
- Laboratory of Theoretical and Computational Biophysics & Faculty of Applied Sciences, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
| | - Antoine Loquet
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Mara Chiricotto
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester M13 9PL, U.K
| | - Pritam Ganguly
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - James McCarty
- Chemistry Department, Western Washington University, Bellingham, Washington 98225, United States
| | - Mai Suan Li
- Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City 700000, Vietnam
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Carol Hall
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yiming Wang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yifat Miller
- Department of Chemistry and The Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | | | - Birgit Habenstein
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Stepan Timr
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Jiaxing Chen
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Brianna Hnath
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative Diseases, and Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Sylvain Lesné
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science, Multiscale Research Institute of Complex Systems, Fudan University, Shanghai 200438, China
| | - Fabio Sterpone
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Andrew J Doig
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Philippe Derreumaux
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
- Laboratory of Theoretical Chemistry, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
- Faculty of Pharmacy, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
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52
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Mahmoudinobar F, Nilsson BL, Dias CL. Effects of Ions and Small Compounds on the Structure of Aβ 42 Monomers. J Phys Chem B 2021; 125:1085-1097. [PMID: 33481611 DOI: 10.1021/acs.jpcb.0c09617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aggregation of amyloid-β (Aβ) proteins in the brain is a hallmark of Alzheimer's disease. This phenomenon can be promoted or inhibited by adding small molecules to the solution where Aβ is embedded. These molecules affect the ensemble of conformations sampled by Aβ monomers even before aggregation starts. Here, we perform extensive all-atom replica exchange molecular dynamics (REMD) simulations to provide a comparative study of the ensemble of conformations sampled by Aβ42 monomers in solutions that promote (i.e., aqueous solution containing NaCl) and inhibit (i.e., aqueous solutions containing scyllo-inositol or 4-aminophenol) aggregation. Simulations performed in pure water are used as our reference. We find that secondary-structure content is only affected in an antagonistic manner by promoters and inhibitors at the C-terminus and the central hydrophilic core. Moreover, the end of the C-terminus binds more favorably to the central hydrophobic core region of Aβ42 in NaCl adopting a type of strand-loop-strand structure that is disfavored by inhibitors. Nonpolar residues that form the dry core of larger aggregates of Aβ42 (e.g., PDB ID 2BEG) are found at close proximity in these strand-loop-strand structures, suggesting that their formation could play an important role in initiating nucleation. In the presence of inhibitors, the C-terminus binds the central hydrophilic core with a higher probability than in our reference simulation. This sensitivity of the C-terminus, which is affected in an antagonistic manner by inhibitors and promoters, provides evidence for its critical role in accounting for aggregation.
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Affiliation(s)
- Farbod Mahmoudinobar
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
| | - Bradley L Nilsson
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Cristiano L Dias
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
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53
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Alderson TR, Kay LE. NMR spectroscopy captures the essential role of dynamics in regulating biomolecular function. Cell 2021; 184:577-595. [PMID: 33545034 DOI: 10.1016/j.cell.2020.12.034] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/09/2020] [Accepted: 12/21/2020] [Indexed: 01/02/2023]
Abstract
Biomolecules are in constant motion. To understand how they function, and why malfunctions can cause disease, it is necessary to describe their three-dimensional structures in terms of dynamic conformational ensembles. Here, we demonstrate how nuclear magnetic resonance (NMR) spectroscopy provides an essential, dynamic view of structural biology that captures biomolecular motions at atomic resolution. We focus on examples that emphasize the diversity of biomolecules and biochemical applications that are amenable to NMR, such as elucidating functional dynamics in large molecular machines, characterizing transient conformations implicated in the onset of disease, and obtaining atomic-level descriptions of intrinsically disordered regions that make weak interactions involved in liquid-liquid phase separation. Finally, we discuss the pivotal role that NMR has played in driving forward our understanding of the biomolecular dynamics-function paradigm.
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Affiliation(s)
- T Reid Alderson
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Chemistry, The University of Toronto, Toronto, ON M5S A18, Canada.
| | - Lewis E Kay
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Chemistry, The University of Toronto, Toronto, ON M5S A18, Canada; Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada.
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54
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Barz B, Buell AK, Nath S. Compact fibril-like structure of amyloid β-peptide (1-42) monomers. Chem Commun (Camb) 2021; 57:947-950. [PMID: 33399148 DOI: 10.1039/d0cc06607a] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Amyloid β (Aβ) monomers are the smallest assembly units, and play an important role in most of the individual processes involved in amyloid fibril formation. An important question is whether the monomer can adopt transient fibril-like conformations in solution. Here we use enhanced sampling simulations to study the Aβ42 monomer structural flexibility. We show that the monomer frequently adopts conformations with the N-terminus region structured very similarly to the conformation it adopts inside the fibril. This intrinsic propensity of monomeric Aβ to adopt fibril-like conformations could explain the low free energy barrier for Aβ42 fibril elongation.
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Affiliation(s)
- Bogdan Barz
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany and Institute of Biological Information Processing - Structural Biochemistry (IBI-7), Research Centre Jülich, Jülich, Germany.
| | - Alexander K Buell
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Soumav Nath
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany and Institute of Biological Information Processing - Structural Biochemistry (IBI-7), Research Centre Jülich, Jülich, Germany.
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55
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Yu L, Li DW, Brüschweiler R. Systematic Differences between Current Molecular Dynamics Force Fields To Represent Local Properties of Intrinsically Disordered Proteins. J Phys Chem B 2021; 125:798-804. [PMID: 33444020 DOI: 10.1021/acs.jpcb.0c10078] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The prevalence of intrinsically disordered proteins (IDPs) and protein regions in structural biology has prompted the recent development of molecular dynamics (MD) force fields for the more realistic representations of such systems. Using experimental nuclear magnetic resonance backbone scalar 3J-coupling constants of the intrinsically disordered proteins α-synuclein and amyloid-β in their native aqueous environment as a metric, we compare the performance of four recent MD force fields, namely, AMBER ff14SB, CHARMM C36m, AMBER ff99SB-disp, and AMBER ff99SBnmr2, by partitioning the polypeptides into an overlapping series of heptapeptides for which a cumulative total of 276 μs MD simulations were performed. The results show substantial differences between the different force fields at the individual residue level. Except for ff99SBnmr2, the force fields systematically underestimate the scalar 3J(HN,Hα)-couplings due to an underrepresentation of β-conformations and an overrepresentation of either α- or PPII conformations. The study demonstrates that the incorporation of coil library information in modern MD force fields, as shown here for ff99SBnmr2, provides substantially improved performance and more realistic sampling of the local backbone dihedral angles of IDPs as reflected by the good accuracy of the computed scalar 3J(HN,Hα)-couplings with less than 0.5 Hz error. Such force fields will enable a better understanding of how structural dynamics and thermodynamics influence the IDP function. Although the methodology based on heptapeptides used here does not allow the assessment of potential intramolecular long-range interactions, its computational affordability permits well-converged simulations that can be easily parallelized. This should make the quantitative validation of intrinsic disorder observed in MD simulations of polypeptides with experimental scalar J-couplings widely applicable.
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Affiliation(s)
- Lei Yu
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Da-Wei Li
- Campus Chemical Instrument Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Rafael Brüschweiler
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.,Campus Chemical Instrument Center, The Ohio State University, Columbus, Ohio 43210, United States.,Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio 43210, United States
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56
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Löhr T, Kohlhoff K, Heller GT, Camilloni C, Vendruscolo M. A kinetic ensemble of the Alzheimer's Aβ peptide. NATURE COMPUTATIONAL SCIENCE 2021; 1:71-78. [PMID: 38217162 DOI: 10.1038/s43588-020-00003-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 11/24/2020] [Indexed: 01/15/2024]
Abstract
The conformational and thermodynamic properties of disordered proteins are commonly described in terms of structural ensembles and free energy landscapes. To provide information on the transition rates between the different states populated by these proteins, it would be desirable to generalize this description to kinetic ensembles. Approaches based on the theory of stochastic processes can be particularly suitable for this purpose. Here, we develop a Markov state model and apply it to determine a kinetic ensemble of Aβ42, a disordered peptide associated with Alzheimer's disease. Through the Google Compute Engine, we generated 315-µs all-atom molecular dynamics trajectories. Using a probabilistic-based definition of conformational states in a neural network approach, we found that Aβ42 is characterized by inter-state transitions on the microsecond timescale, exhibiting only fully unfolded or short-lived, partially folded states. Our results illustrate how kinetic ensembles provide effective information about the structure, thermodynamics and kinetics of disordered proteins.
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Affiliation(s)
- Thomas Löhr
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | | | - Carlo Camilloni
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
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57
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Kakeshpour T, Ramanujam V, Barnes CA, Shen Y, Ying J, Bax A. A lowly populated, transient β-sheet structure in monomeric Aβ 1-42 identified by multinuclear NMR of chemical denaturation. Biophys Chem 2020; 270:106531. [PMID: 33453683 DOI: 10.1016/j.bpc.2020.106531] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/08/2020] [Accepted: 12/13/2020] [Indexed: 02/07/2023]
Abstract
Chemical denaturation is a well-established approach for probing the equilibrium between folded and unfolded states of proteins. We demonstrate applicability of this method to the detection of a small population of a transiently folded structural element in a system that is often considered to be intrinsically fully disordered. The 1HN, 15N, 13Cα, and 13C' chemical shifts of Aβ1-40 and Aβ1-42 peptides and their M35-oxidized variants were monitored as a function of urea concentration and compared to analogous urea titrations of synthetic pentapeptides of homologous sequence. Fitting of the chemical shift titrations yields a 10 ± 1% population for a structured element at the C-terminus of Aβ1-42 that folds with a cooperativity of m = 0.06 kcal/mol·M. The fit also yields the chemical shifts of the folded state and, using a database search, for Aβ1-42 these shifts identified an antiparallel intramolecular β-sheet for residues I32-A42, linked by a type I' β-turn at G37 and G38. The structure is destabilized by oxidation of M35. Paramagnetic relaxation rates and two previously reported weak, medium-range NOE interactions are consistent with this transient β-sheet. Introduction of the requisite A42C mutation and tagging with MTSL resulted in a small stabilization of this β-sheet. Chemical shift analysis suggests a C-terminal β-sheet may be present in Aβ1-40 too, but the turn type at G37 is not type I'. The approach to derive Transient Structure from chemical Denaturation by NMR (TSD-NMR), demonstrated here for Aβ peptides, provides a sensitive tool for identifying the presence of lowly populated, transiently ordered elements in proteins that are considered to be intrinsically disordered, and permits extraction of structural data for such elements.
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Affiliation(s)
- Tayeb Kakeshpour
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Venkat Ramanujam
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - C Ashley Barnes
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
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58
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Kaur A, Goyal D, Goyal B. An α-helix mimetic oligopyridylamide, ADH-31, modulates Aβ 42 monomer aggregation and destabilizes protofibril structures: insights from molecular dynamics simulations. Phys Chem Chem Phys 2020; 22:28055-28073. [PMID: 33289734 DOI: 10.1039/d0cp04672h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease (AD), an epidemic growing worldwide due to no effective medical aid available in the market, is a neurological disorder. AD is known to be directly associated with the toxicity of amyloid-β (Aβ) aggregates. In search of potent inhibitors of Aβ aggregation, Hamilton and co-workers reported an α-helix mimetic, ADH-31, which acts as a powerful antagonist of Aβ42 aggregation. To identify the key interactions between protein-ligand complexes and to gain insights into the inhibitory mechanism of ADH-31 against Aβ42 aggregation, molecular dynamics (MD) simulations were performed in the present study. The MD simulations highlighted that ADH-31 showed distinct binding capabilities with residues spanning from the N-terminal to the central hydrophobic core (CHC) region of Aβ42 and restricted the conformational transition of the helix-rich structure of Aβ42 into another form of secondary structures (coil/turn/β-sheet). Hydrophobic contacts, hydrogen bonding and π-π interaction contribute to the strong binding between ADH-31 and Aβ42 monomer. The Dictionary of Secondary Structure of Proteins (DSSP) analysis highlighted that the probability of helical content increases from 38.5% to 50.2% and the turn content reduces from 14.7% to 6.2% with almost complete loss of the β-sheet structure (4.5% to 0%) in the Aβ42 monomer + ADH-31 complex. The per-residue binding free energy analysis demonstrated that Arg5, Tyr10, His14, Gln15, Lys16, Val18, Phe19 and Lys28 residues of Aβ42 are responsible for the favourable binding free energy in Aβ42 monomer + ADH-31 complex, which is consistent with the 2D HSQC NMR of the Aβ42 monomer that depicted a change in the chemical shift of residues spanning from Glu11 to Phe20 in the presence of ADH-31. The MD simulations highlighted the prevention of sampling of amyloidogenic β-strand conformations in Aβ42 trimer in the presence of ADH-31 as well as the ability of ADH-31 to destabilize Aβ42 trimer and protofibril structures. The lower binding affinity between Aβ42 trimer chains in the presence of ADH-31 highlights the destabilization of the Aβ42 trimer structure. Overall, MD results highlighted that ADH-31 inhibited Aβ42 aggregation by constraining Aβ peptides into helical conformation and destabilized Aβ42 trimer as well as protofibril structures. The present study provides a theoretical insight into the atomic level details of the inhibitory mechanism of ADH-31 against Aβ42 aggregation as well as protofibril destabilization and could be implemented in the structure-based drug design of potent therapeutic agents for AD.
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Affiliation(s)
- Anupamjeet Kaur
- Department of Chemistry, Faculty of Basic and Applied Sciences, Sri Guru Granth Sahib World University, Fatehgarh Sahib-140406, Punjab, India.
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59
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McCoy MD, Hamre J, Klimov DK, Jafri MS. Predicting Genetic Variation Severity Using Machine Learning to Interpret Molecular Simulations. Biophys J 2020; 120:189-204. [PMID: 33333034 DOI: 10.1016/j.bpj.2020.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 11/20/2020] [Accepted: 12/08/2020] [Indexed: 02/08/2023] Open
Abstract
Distinct missense mutations in a specific gene have been associated with different diseases as well as differing severity of a disease. Current computational methods predict the potential pathogenicity of a missense variant but fail to differentiate between separate disease or severity phenotypes. We have developed a method to overcome this limitation by applying machine learning to features extracted from molecular dynamics simulations, creating a way to predict the effect of novel genetic variants in causing a disease, drug resistance, or another specific trait. As an example, we have applied this novel approach to variants in calmodulin associated with two distinct arrhythmias as well as two different neurodegenerative diseases caused by variants in amyloid-β peptide. The new method successfully predicts the specific disease caused by a gene variant and ranks its severity with more accuracy than existing methods. We call this method molecular dynamics phenotype prediction model.
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Affiliation(s)
- Matthew D McCoy
- Innovation Center for Biomedical Informatics, Department of Oncology, Georgetown University Medical Center, Georgetown University, Washington DC; School of Systems Biology, George Mason University, Manassas, Virginia.
| | - John Hamre
- School of Systems Biology, George Mason University, Manassas, Virginia
| | - Dmitri K Klimov
- School of Systems Biology, George Mason University, Manassas, Virginia
| | - M Saleet Jafri
- School of Systems Biology, George Mason University, Manassas, Virginia; Krasnow Institute for Advanced Study, Interdisciplinary Program in Neuroscience, School of Systems Biology, George Mason University, Fairfax, Virginia.
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60
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Nguyen H, Linh HQ, Matteini P, La Penna G, Li MS. Emergence of Barrel Motif in Amyloid-β Trimer: A Computational Study. J Phys Chem B 2020; 124:10617-10631. [PMID: 33180492 PMCID: PMC7735726 DOI: 10.1021/acs.jpcb.0c05508] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/29/2020] [Indexed: 12/20/2022]
Abstract
Amyloid-β (Aβ) peptides form assemblies that are pathological hallmarks of Alzheimer's disease. Aβ oligomers are soluble, mobile, and toxic forms of the peptide that act in the extracellular space before assembling into protofibrils and fibrils. Therefore, oligomers play an important role in the mechanism of Alzheimer's disease. Since it is difficult to determine by experiment the atomic structures of oligomers, which accumulate fast and are polymorphic, computer simulation is a useful tool to investigate elusive oligomers' structures. In this work, we report extended all-atom molecular dynamics simulations, both canonical and replica exchange, of Aβ(1-42) trimer starting from two different initial conformations: (i) the pose produced by the best docking of a monomer aside of a dimer (simulation 1), representing oligomers freshly formed by assembling monomers, and (ii) a configuration extracted from an experimental mature fibril structure (simulation 2), representing settled oligomers in equilibrium with extended fibrils. We showed that in simulation 1, regions with small β-barrels are populated, indicating the chance of spontaneous formation of domains resembling channel-like structures. These structural domains are alternative to those more representative of mature fibrils (simulation 2), the latter showing a stable bundle of C-termini that is not sampled in simulation 1. Moreover, trimer of Aβ(1-42) can form internal pores that are large enough to be accessed by water molecules and Ca2+ ions.
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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
- Ho
Chi Minh City University of Technology (HCMUT), Ho Chi Minh City 700000, Vietnam
- Vietnam
National University, Ho Chi Minh
City 700000, Vietnam
| | - Huynh Quang Linh
- Ho
Chi Minh City University of Technology (HCMUT), Ho Chi Minh City 700000, Vietnam
- Vietnam
National University, Ho Chi Minh
City 700000, Vietnam
| | - Paolo Matteini
- Institute
of Applied Physics “Nello Carrara”, National Research Council, Via Madonna Del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Giovanni La Penna
- National
Research Council of Italy (CNR), Institute
for Chemistry of Organometallic Compounds (ICCOM), 50019 Florence, Italy
- National Institute for Nuclear Physics
(INFN), Section of Roma-Tor
Vergata Institute of Physics, Polish Academy of
Sciences, Al. Lotnikow
32/46, 02-668 Warsaw, Poland
| | - Mai Suan Li
- National Institute for Nuclear Physics
(INFN), Section of Roma-Tor
Vergata Institute of Physics, Polish Academy of
Sciences, Al. Lotnikow
32/46, 02-668 Warsaw, Poland
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61
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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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62
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Noda K, Tachi Y, Okamoto Y. Structural Characteristics of Monomeric Aβ42 on Fibril in the Early Stage of Secondary Nucleation Process. ACS Chem Neurosci 2020; 11:2989-2998. [PMID: 32794732 DOI: 10.1021/acschemneuro.0c00163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Amyloid-β (Aβ) aggregates are believed to be one of the main causes of Alzheimer's disease. Aβ peptides form fibrils having cross β-sheet structures mainly through primary nucleation, secondary nucleation, and elongation. In particular, self-catalyzed secondary nucleation is of great interest. Here, we investigate the adsorption of Aβ42 peptides to the Aβ42 fibril to reveal a role of adsorption as a part of secondary nucleation. We performed extensive molecular dynamics simulations based on replica exchange with solute tempering 2 (REST2) to two systems: a monomeric Aβ42 in solution and a complex of an Aβ42 peptide and Aβ42 fibril. Results of our simulations show that the Aβ42 monomer is extended on the fibril. Furthermore, we find that the hairpin structure of the Aβ42 monomer decreases but the helix structure increases by adsorption to the fibril surface. These structural changes are preferable for forming fibril-like aggregates, suggesting that the fibril surface serves as a catalyst in the secondary nucleation process. In addition, the stabilization of the helix structure of the Aβ42 monomer on the fibril indicates that the strategy of a secondary nucleation inhibitor design for Aβ40 can also be used for Aβ42.
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Affiliation(s)
- Kohei Noda
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Yuhei Tachi
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Yuko Okamoto
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
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63
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Hyaluronan-carnosine conjugates inhibit Aβ aggregation and toxicity. Sci Rep 2020; 10:15998. [PMID: 32994475 PMCID: PMC7524733 DOI: 10.1038/s41598-020-72989-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/27/2020] [Indexed: 12/25/2022] Open
Abstract
Alzheimer’s disease is the most common neurodegenerative disorder. Finding a pharmacological approach that cures and/or prevents the onset of this devastating disease represents an important challenge for researchers. According to the amyloid cascade hypothesis, increases in extracellular amyloid-β (Aβ) levels give rise to different aggregated species, such as protofibrils, fibrils and oligomers, with oligomers being the more toxic species for cells. Many efforts have recently been focused on multi-target ligands to address the multiple events that occur concurrently with toxic aggregation at the onset of the disease. Moreover, investigating the effect of endogenous compounds or a combination thereof is a promising approach to prevent the side effects of entirely synthetic drugs. In this work, we report the synthesis, structural characterization and Aβ antiaggregant ability of new derivatives of hyaluronic acid (Hy, 200 and 700 kDa) functionalized with carnosine (Car), a multi-functional natural dipeptide. The bioactive substances (HyCar) inhibit the formation of amyloid-type aggregates of Aβ42 more than the parent compounds; this effect is proportional to Car loading. Furthermore, the HyCar derivatives are able to dissolve the amyloid fibrils and to reduce Aβ-induced toxicity in vitro. The enzymatic degradation of Aβ is also affected by the interaction with HyCar.
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64
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Amirkulova DB, Chakraborty M, White AD. Experimentally Consistent Simulation of Aβ 21-30 Peptides with a Minimal NMR Bias. J Phys Chem B 2020; 124:8266-8277. [PMID: 32845146 DOI: 10.1021/acs.jpcb.0c07129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Misfolded amyloid peptides are neurotoxic molecules associated with Alzheimer's disease. The Aβ21-30 peptide fragment is a decapeptide fragment of the complete Aβ42 peptide which is a hypothesized cause of Alzheimer's disease via amyloid fibrillogenesis. Aβ21-30 is investigated here with a combination of NMR (nuclear magnetic resonance) spectroscopy experiments and molecular dynamics simulations with experiment directed simulation (EDS). EDS is a maximum entropy biasing method that augments a molecular dynamics simulation with experimental data (NMR chemical shifts) to improve agreement with experiments and thus accuracy. EDS molecular dynamics shows that the Aβ21-30 monomer has a β turn stabilized by the following interactions: S26-K28, D23-S26, and D23-K28. NMR, total correlation spectroscopy, and rotating frame Overhauser effect spectroscopy experiments provide independent agreement. Subsequent two- and four-monomer EDS simulations show aggregation. Diffusion coefficients calculated from molecular simulation also agreed with experimentally measured values only after using EDS, providing independent assessment of accuracy. This work demonstrates how accuracy can be improved by directly using experimental data in molecular dynamics of complex processes like self-assembly.
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Affiliation(s)
- Dilnoza B Amirkulova
- Department of Chemical Engineering, University of Rochester, Rochester, New York 14627, United States
| | - Maghesree Chakraborty
- Department of Chemical Engineering, University of Rochester, Rochester, New York 14627, United States
| | - Andrew D White
- Department of Chemical Engineering, University of Rochester, Rochester, New York 14627, United States
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65
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Ikenoue T, Aprile FA, Sormanni P, Ruggeri FS, Perni M, Heller GT, Haas CP, Middel C, Limbocker R, Mannini B, Michaels TCT, Knowles TPJ, Dobson CM, Vendruscolo M. A rationally designed bicyclic peptide remodels Aβ42 aggregation in vitro and reduces its toxicity in a worm model of Alzheimer's disease. Sci Rep 2020; 10:15280. [PMID: 32943652 PMCID: PMC7498612 DOI: 10.1038/s41598-020-69626-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/26/2020] [Indexed: 01/01/2023] Open
Abstract
Bicyclic peptides have great therapeutic potential since they can bridge the gap between small molecules and antibodies by combining a low molecular weight of about 2 kDa with an antibody-like binding specificity. Here we apply a recently developed in silico rational design strategy to produce a bicyclic peptide to target the C-terminal region (residues 31–42) of the 42-residue form of the amyloid β peptide (Aβ42), a protein fragment whose aggregation into amyloid plaques is linked with Alzheimer’s disease. We show that this bicyclic peptide is able to remodel the aggregation process of Aβ42 in vitro and to reduce its associated toxicity in vivo in a C. elegans worm model expressing Aβ42. These results provide an initial example of a computational approach to design bicyclic peptides to target specific epitopes on disordered proteins.
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Affiliation(s)
- Tatsuya Ikenoue
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.,Department of Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Francesco A Aprile
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.,Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK
| | - Pietro Sormanni
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Francesco S Ruggeri
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Michele Perni
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Gabriella T Heller
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Christian P Haas
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Christoph Middel
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Ryan Limbocker
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.,Department of Chemistry and Life Science, United States Military Academy, West Point, NY, 10996, USA
| | - Benedetta Mannini
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Thomas C T Michaels
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Christopher M Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
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66
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Curcumin Inhibits the Primary Nucleation of Amyloid-Beta Peptide: A Molecular Dynamics Study. Biomolecules 2020; 10:biom10091323. [PMID: 32942739 PMCID: PMC7563689 DOI: 10.3390/biom10091323] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/07/2020] [Accepted: 09/12/2020] [Indexed: 12/11/2022] Open
Abstract
The amyloid plaques are a key hallmark of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Amyloidogenesis is a complex long-lasting multiphase process starting with the formation of nuclei of amyloid peptides: a process assigned as a primary nucleation. Curcumin (CU) is a well-known inhibitor of the aggregation of amyloid-beta (Aβ) peptides. Even more, CU is able to disintegrate preformed Aβ firbils and amyloid plaques. Here, we simulate by molecular dynamics the primary nucleation process of 12 Aβ peptides and investigate the effects of CU on the process. We found that CU molecules intercalate among the Aβ chains and bind tightly to them by hydrogen bonds, hydrophobic, π–π, and cation–π interactions. In the presence of CU, the Aβ peptides form a primary nucleus of a bigger size. The peptide chains in the nucleus become less flexible and more disordered, and the number of non-native contacts and hydrogen bonds between them decreases. For comparison, the effects of the weaker Aβ inhibitor ferulic acid (FA) on the primary nucleation are also examined. Our study is in good agreement with the observation that taken regularly, CU is able to prevent or at least delay the onset of neurodegenerative disorders.
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67
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Gera J, Paragi G. Fluorescence-Labeled Amyloid Beta Monomer: A Molecular Dynamical Study. Molecules 2020; 25:molecules25153524. [PMID: 32752239 PMCID: PMC7435871 DOI: 10.3390/molecules25153524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 11/19/2022] Open
Abstract
The aggregation process of the Amyloidβ (Aβ) peptide is one of the central questions in Alzheimers’s research. Fluorescence-labeled single-molecule detection is a novel technique concerning the early stage investigation of Aβ aggregation, where the labeling dyes are covalently bound to the Aβ monomer. As the influence of the dye on the conformational space of the Aβ monomer can be significant, its effect on the seeding process is an open question. The applied fluorescent molecule continuously switches between an active (ON) and an inactive (OFF) state, where the latter supports an extra rotational restriction at many commercially available dyes. However, only a few theoretical studies simulated the Aβ monomer in the presence of a dye and none of them considered the difference between the ON and the OFF states. Therefore, we examined the impact of a selected fluorescence dye (Alexa 568) on the conformational space of the monomeric Aβ(1–42) peptide in its ON and OFF state by replica exchange molecular dynamic simulations. Investigations on secondary structure elements as well as dye-peptide contact analysis for the monomers are presented. Experimental and theoretical NMR shifts were contrasted to qualify the calculation protocol and theoretical values of the labeled and the non-labeled peptide were also compared. We found that the first five residues have higher helical propensity in the presence of the dye, and electrostatic properties could strongly affect the connection between the dye and the peptide parts.
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Affiliation(s)
- János Gera
- Department of Medical Chemistry, University of Szeged, H-6720 Dóm square 8, 6720 Szeged, Hungary;
| | - Gábor Paragi
- MTA-SZTE Biomimetic Systems Research Group, Department of Medical Chemistry, University of Szeged, H-6720 Dóm square 8, 6720 Szeged, Hungary
- Institute of Physics, University of Pecs, H-7624 Ifjusag utja 6, 7624 Pecs, Hungary
- Correspondence: or ; Tel.: +36-62-544-4593
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68
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Differences in the free energies between the excited states of A β40 and A β42 monomers encode their aggregation propensities. Proc Natl Acad Sci U S A 2020; 117:19926-19937. [PMID: 32732434 DOI: 10.1073/pnas.2002570117] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The early events in the aggregation of the intrinsically disordered peptide, amyloid-β (Aβ), involve transitions from the disordered free energy ground state to assembly-competent states. Are the fingerprints of order found in the amyloid fibrils encoded in the conformations that the monomers access at equilibrium? If so, could the enhanced aggregation rate of Aβ42 compared to Aβ40 be rationalized from the sparsely populated high free energy states of the monomers? Here, we answer these questions in the affirmative using coarse-grained simulations of the self-organized polymer-intrinsically disordered protein (SOP-IDP) model of Aβ40 and Aβ42. Although both the peptides have practically identical ensemble-averaged properties, characteristic of random coils (RCs), the conformational ensembles of the two monomers exhibit sequence-specific heterogeneity. Hierarchical clustering of conformations reveals that both the peptides populate high free energy aggregation-prone ([Formula: see text]) states, which resemble the monomers in the fibril structure. The free energy gap between the ground (RC) and the [Formula: see text] states of Aβ42 peptide is smaller than that for Aβ40. By relating the populations of excited states of the two peptides to the fibril formation time scales using an empirical formula, we explain nearly quantitatively the faster aggregation rate of Aβ42 relative to Aβ40. The [Formula: see text] concept accounts for fibril polymorphs, leading to the prediction that the less stable [Formula: see text] state of Aβ42, encoding for the U-bend fibril, should form earlier than the structure with the S-bend topology, which is in accord with Ostwald's rule rationalizing crystal polymorph formation.
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69
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Bera S, Gayen N, Mohid SA, Bhattacharyya D, Krishnamoorthy J, Sarkar D, Choi J, Sahoo N, Mandal AK, Lee D, Bhunia A. Comparison of Synthetic Neuronal Model Membrane Mimics in Amyloid Aggregation at Atomic Resolution. ACS Chem Neurosci 2020; 11:1965-1977. [PMID: 32492332 DOI: 10.1021/acschemneuro.0c00166] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Alzheimer's disease (AD) is a severe neurodegenerative disorder caused by abnormal accumulation of toxic amyloid plaques of the amyloid-beta (Aβ) or the tau proteins in the brain. The plaque deposition leading to the collapse of the cellular integrity is responsible for a myriad of surface phenomena acting at the neuronal lipid interface. Recent years have witnessed dysfunction of the blood-brain barriers (BBB) associated with AD. Several studies support the idea that BBB acts as a platform for the formation of misfolded Aβ peptide, promoting oligomerization and fibrillation, compromising the overall integrity of the central nervous system. While the amyloid plaque deposition has been known to be responsible for the collapse of the BBB membrane integrity, the causal effect relationship between BBB and Aβ amyloidogenesis remains unclear. In this study, we have used physiologically relevant synthetic model membrane systems to gain atomic insight into the functional aspects of the lipid interface. Here, we have used a minimalist BBB mimic, POPC/POPG/cholesterol/GM1, to compare with the native BBB (total lipid brain extract (TLBE)), to understand the molecular events occurring in the membrane-induced Aβ40 amyloid aggregation. Our study showed that the two membrane models accelerated the Aβ40 aggregation kinetics with differential secondary structural transitions of the peptide. The observed structural transitions are defined by the lipid compositions, which in turn undermines the differences in lipid surface phenomena, leading to peptide induced cellular toxicity in the neuronal membrane.
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Affiliation(s)
- Swapna Bera
- Department of Biophysics, Bose Institute, Kolkata 700054, India
| | - Nilanjan Gayen
- Division of Molecular Medicine, Bose Institute, Kolkata 700054, India
| | - Sk. Abdul Mohid
- Department of Biophysics, Bose Institute, Kolkata 700054, India
| | | | | | - Dibakar Sarkar
- Department of Biophysics, Bose Institute, Kolkata 700054, India
| | - Jihye Choi
- Department of Fine Chemistry & Convergence Institute of Biomedical and Biomaterials, Seoul National University of Science and Technology, Seoul 139-743, Korea
| | - Nirakar Sahoo
- Department of Biology, University of Texas Rio Grande Valley, Edinburg, Texas 78539, United States
| | - Atin K. Mandal
- Division of Molecular Medicine, Bose Institute, Kolkata 700054, India
| | - DongKuk Lee
- Department of Fine Chemistry & Convergence Institute of Biomedical and Biomaterials, Seoul National University of Science and Technology, Seoul 139-743, Korea
| | - Anirban Bhunia
- Department of Biophysics, Bose Institute, Kolkata 700054, India
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70
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Structures of the intrinsically disordered Aβ, tau and α-synuclein proteins in aqueous solution from computer simulations. Biophys Chem 2020; 264:106421. [PMID: 32623047 DOI: 10.1016/j.bpc.2020.106421] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/21/2022]
Abstract
Intrinsically disordered proteins (IDPs) play many biological roles in the human proteome ranging from vesicular transport, signal transduction to neurodegenerative diseases. The Aβ and tau proteins, and the α-synuclein protein, key players in Alzheimer's and Parkinson's diseases, respectively are fully disordered at the monomer level. The structural heterogeneity of the monomeric and oligomeric states and the high self-assembly propensity of these three IDPs have precluded experimental structural determination. Simulations have been used to determine the atomic structures of these IDPs. In this article, we review recent computer models to capture the equilibrium ensemble of Aβ, tau and α-synuclein proteins at different association steps in aqueous solution and present new results of the PEP-FOLD framework on α-synuclein monomer.
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71
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Kaur A, Kaur A, Goyal D, Goyal B. How Does the Mono-Triazole Derivative Modulate Aβ 42 Aggregation and Disrupt a Protofibril Structure: Insights from Molecular Dynamics Simulations. ACS OMEGA 2020; 5:15606-15619. [PMID: 32637837 PMCID: PMC7331201 DOI: 10.1021/acsomega.0c01825] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/08/2020] [Indexed: 05/31/2023]
Abstract
Clinical studies have identified that abnormal self-assembly of amyloid-β (Aβ) peptide into toxic fibrillar aggregates is associated with the pathology of Alzheimer's disease (AD). The most acceptable therapeutic approach to stop the progression of AD is to inhibit the formation of β-sheet-rich structures. Recently, we designed and evaluated a series of novel mono-triazole derivatives 4(a-x), where compound 4v was identified as the most potent inhibitor of Aβ42 aggregation and disaggregates preformed Aβ42 fibrils significantly. Moreover, 4v strongly averts the Cu2+-induced Aβ42 aggregation and disaggregates the preformed Cu2+-induced Aβ42 fibrils, halts the generation of reactive oxygen species, and shows neuroprotective effects in SH-SY5Y cells. However, the underlying molecular mechanism of inhibition of Aβ42 aggregation by 4v and disaggregation of preformed Aβ42 fibrils remains obscure. In this work, molecular dynamics (MD) simulations have been performed to explore the conformational ensemble of the Aβ42 monomer and a pentameric protofibril structure of Aβ42 in the presence of 4v. The MD simulations highlighted that 4v binds preferentially at the central hydrophobic core region of the Aβ42 monomer and chains D and E of the Aβ42 protofibril. The dictionary of secondary structure of proteins analysis indicated that 4v retards the conformational conversion of the helix-rich structure of the Aβ42 monomer into the aggregation-prone β-sheet conformation. The binding free energy calculated by the molecular mechanics Poisson-Boltzmann surface area method revealed an energetically favorable process with ΔG binding = -44.9 ± 3.3 kcal/mol for the Aβ42 monomer-4v complex. The free energy landscape analysis highlighted that the Aβ42 monomer-4v complex sampled conformations with significantly higher helical contents (35 and 49%) as compared to the Aβ42 monomer alone (17%). Compound 4v displayed hydrogen bonding with Gly37 (chain E) and π-π interactions with Phe19 (chain D) of the Aβ42 protofibril. Further, the per-residue binding free energy analysis also highlighted that Phe19 (chain D) and Gly37 (chain E) of the Aβ42 protofibril showed the maximum contribution in the binding free energy. The decreased binding affinity and residue-residue contacts between chains D and E of the Aβ42 protofibril in the presence of 4v indicate destabilization of the Aβ42 protofibril structure. Overall, the structural information obtained through MD simulations indicated that 4v stabilizes the native helical conformation of the Aβ42 monomer and persuades a destabilization in the protofibril structure of Aβ42. The results of the study will be useful in the rational design of potent inhibitors against amyloid aggregation.
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Affiliation(s)
- Amandeep Kaur
- Department
of Chemistry, Faculty of Basic and Applied Sciences, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, Punjab, India
| | - Anupamjeet Kaur
- Department
of Chemistry, Faculty of Basic and Applied Sciences, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, Punjab, India
| | - Deepti Goyal
- Department
of Chemistry, Faculty of Basic and Applied Sciences, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, Punjab, India
| | - Bhupesh Goyal
- School
of Chemistry & Biochemistry, Thapar
Institute of Engineering & Technology, Patiala 147004, Punjab, India
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72
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Watanabe-Nakayama T, Sahoo BR, Ramamoorthy A, Ono K. High-Speed Atomic Force Microscopy Reveals the Structural Dynamics of the Amyloid-β and Amylin Aggregation Pathways. Int J Mol Sci 2020; 21:E4287. [PMID: 32560229 PMCID: PMC7352471 DOI: 10.3390/ijms21124287] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/09/2020] [Accepted: 06/14/2020] [Indexed: 12/18/2022] Open
Abstract
Individual Alzheimer's disease (AD) patients have been shown to have structurally distinct amyloid-β (Aβ) aggregates, including fibrils, in their brain. These findings suggest the possibility of a relationship between AD progression and Aβ fibril structures. Thus, the characterization of the structural dynamics of Aβ could aid the development of novel therapeutic strategies and diagnosis. Protein structure and dynamics have typically been studied separately. Most of the commonly used biophysical approaches are limited in providing substantial details regarding the combination of both structure and dynamics. On the other hand, high-speed atomic force microscopy (HS-AFM), which simultaneously visualizes an individual protein structure and its dynamics in liquid in real time, can uniquely link the structure and the kinetic details, and it can also unveil novel insights. Although amyloidogenic proteins generate heterogeneously aggregated species, including transient unstable states during the aggregation process, HS-AFM elucidated the structural dynamics of individual aggregates in real time in liquid without purification and isolation. Here, we review and discuss the HS-AFM imaging of amyloid aggregation and strategies to optimize the experiments showing findings from Aβ and amylin, which is associated with type II diabetes, shares some common biological features with Aβ, and is reported to be involved in AD.
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Affiliation(s)
| | - Bikash R. Sahoo
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, and Biomedical Engineering, The University of Michigan, Ann Arbor, MI 48109-1055, USA;
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA;
| | - Kenjiro Ono
- Division of Neurology, Department of Internal Medicine, School of Medicine, Showa University, Hatanodai, Shinagawa district, Tokyo 142-8666, Japan;
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73
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Wallin C, Jarvet J, Biverstål H, Wärmländer S, Danielsson J, Gräslund A, Abelein A. Metal ion coordination delays amyloid-β peptide self-assembly by forming an aggregation-inert complex. J Biol Chem 2020; 295:7224-7234. [PMID: 32241918 PMCID: PMC7247290 DOI: 10.1074/jbc.ra120.012738] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/01/2020] [Indexed: 01/28/2023] Open
Abstract
A detailed understanding of the molecular pathways for amyloid-β (Aβ) peptide aggregation from monomers into amyloid fibrils, a hallmark of Alzheimer's disease, is crucial for the development of diagnostic and therapeutic strategies. We investigate the molecular details of peptide fibrillization in vitro by perturbing this process through addition of differently charged metal ions. Here, we used a monovalent probe, the silver ion, that, similarly to divalent metal ions, binds to monomeric Aβ peptide and efficiently modulates Aβ fibrillization. On the basis of our findings, combined with our previous results on divalent zinc ions, we propose a model that links the microscopic metal-ion binding to Aβ monomers to its macroscopic impact on the peptide self-assembly observed in bulk experiments. We found that substoichiometric concentrations of the investigated metal ions bind specifically to the N-terminal region of Aβ, forming a dynamic, partially compact complex. The metal-ion bound state appears to be incapable of aggregation, effectively reducing the available monomeric Aβ pool for incorporation into fibrils. This is especially reflected in a decreased fibril-end elongation rate. However, because the bound state is significantly less stable than the amyloid state, Aβ peptides are only transiently redirected from fibril formation, and eventually almost all Aβ monomers are integrated into fibrils. Taken together, these findings unravel the mechanistic consequences of delaying Aβ aggregation via weak metal-ion binding, quantitatively linking the contributions of specific interactions of metal ions with monomeric Aβ to their effects on bulk aggregation.
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Affiliation(s)
- Cecilia Wallin
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Henrik Biverstål
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, 141 52 Huddinge, Sweden; Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga LV-1006, Latvia
| | - Sebastian Wärmländer
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Jens Danielsson
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Axel Abelein
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, 141 52 Huddinge, Sweden.
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74
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Penke B, Szűcs M, Bogár F. Oligomerization and Conformational Change Turn Monomeric β-Amyloid and Tau Proteins Toxic: Their Role in Alzheimer's Pathogenesis. Molecules 2020; 25:molecules25071659. [PMID: 32260279 PMCID: PMC7180792 DOI: 10.3390/molecules25071659] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/29/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
The structural polymorphism and the physiological and pathophysiological roles of two important proteins, β-amyloid (Aβ) and tau, that play a key role in Alzheimer's disease (AD) are reviewed. Recent results demonstrate that monomeric Aβ has important physiological functions. Toxic oligomeric Aβ assemblies (AβOs) may play a decisive role in AD pathogenesis. The polymorph fibrillar Aβ (fAβ) form has a very ordered cross-β structure and is assumed to be non-toxic. Tau monomers also have several important physiological actions; however, their oligomerization leads to toxic oligomers (TauOs). Further polymerization results in probably non-toxic fibrillar structures, among others neurofibrillary tangles (NFTs). Their structure was determined by cryo-electron microscopy at atomic level. Both AβOs and TauOs may initiate neurodegenerative processes, and their interactions and crosstalk determine the pathophysiological changes in AD. TauOs (perhaps also AβO) have prionoid character, and they may be responsible for cell-to-cell spreading of the disease. Both extra- and intracellular AβOs and TauOs (and not the previously hypothesized amyloid plaques and NFTs) may represent the novel targets of AD drug research.
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Affiliation(s)
- Botond Penke
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (M.S.); (F.B.)
- Correspondence:
| | - Mária Szűcs
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (M.S.); (F.B.)
| | - Ferenc Bogár
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (M.S.); (F.B.)
- MTA-SZTE Biomimetic Systems Research Group, University of Szeged, H-6720 Szeged, Hungary
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75
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Wiglenda T, Groenke N, Hoffmann W, Manz C, Diez L, Buntru A, Brusendorf L, Neuendorf N, Schnoegl S, Haenig C, Schmieder P, Pagel K, Wanker EE. Sclerotiorin Stabilizes the Assembly of Nonfibrillar Abeta42 Oligomers with Low Toxicity, Seeding Activity, and Beta-sheet Content. J Mol Biol 2020; 432:2080-2098. [PMID: 32061932 DOI: 10.1016/j.jmb.2020.01.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/14/2020] [Accepted: 01/28/2020] [Indexed: 01/21/2023]
Abstract
The self-assembly of the 42-residue amyloid-β peptide, Aβ42, into fibrillar aggregates is associated with neuronal dysfunction and toxicity in Alzheimer's disease (AD) patient brains, suggesting that small molecules acting on this process might interfere with pathogenesis. Here, we present experimental evidence that the small molecule sclerotiorin (SCL), a natural product belonging to the group of azaphilones, potently delays both seeded and nonseeded Aβ42 polymerization in cell-free assays. Mechanistic biochemical studies revealed that the inhibitory effect of SCL on fibrillogenesis is caused by its ability to kinetically stabilize small Aβ42 oligomers. These structures exhibit low β-sheet content and do not possess seeding activity, indicating that SCL acts very early in the amyloid formation cascade before the assembly of seeding-competent, β-sheet-rich fibrillar aggregates. Investigations with NMR WaterLOGSY experiments confirmed the association of Aβ42 assemblies with SCL in solution. Furthermore, using ion mobility-mass spectrometry, we observed that SCL directly interacts with a small fraction of Aβ42 monomers in the gas phase. In comparison to typical amyloid fibrils, small SCL-stabilized Aβ42 assemblies are inefficiently taken up into mammalian cells and have low toxicity in cell-based assays. Overall, these mechanistic studies support a pathological role of stable, β-sheet-rich Aβ42 fibrils in AD, while structures with low β-sheet content may be less relevant.
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Affiliation(s)
- Thomas Wiglenda
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Nicole Groenke
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Waldemar Hoffmann
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Christian Manz
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Lisa Diez
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Alexander Buntru
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Lydia Brusendorf
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Nancy Neuendorf
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Sigrid Schnoegl
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Christian Haenig
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Peter Schmieder
- Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - Kevin Pagel
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Erich E Wanker
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
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76
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High-yield Production of Amyloid-β Peptide Enabled by a Customized Spider Silk Domain. Sci Rep 2020; 10:235. [PMID: 31937841 PMCID: PMC6959368 DOI: 10.1038/s41598-019-57143-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 12/18/2019] [Indexed: 01/12/2023] Open
Abstract
During storage in the silk gland, the N-terminal domain (NT) of spider silk proteins (spidroins) keeps the aggregation-prone repetitive region in solution at extreme concentrations. We observe that NTs from different spidroins have co-evolved with their respective repeat region, and now use an NT that is distantly related to previously used NTs, for efficient recombinant production of the amyloid-β peptide (Aβ) implicated in Alzheimer’s disease. A designed variant of NT from Nephila clavipes flagelliform spidroin, which in nature allows production and storage of β-hairpin repeat segments, gives exceptionally high yields of different human Aβ variants as a solubility tag. This tool enables efficient production of target peptides also in minimal medium and gives up to 10 times more isotope-labeled monomeric Aβ peptides per liter bacterial culture than previously reported.
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77
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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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78
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Kaur A, Shuaib S, Goyal D, Goyal B. Interactions of a multifunctional di-triazole derivative with Alzheimer's Aβ42monomer and Aβ42protofibril: a systematic molecular dynamics study. Phys Chem Chem Phys 2020; 22:1543-1556. [DOI: 10.1039/c9cp04775a] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The molecular dynamics simulations results highlighted that the multi-target-directed ligand6nstabilizes the native α-helix conformation of the Aβ42monomer and induces a sizable destabilization in the Aβ42protofibril structure.
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Affiliation(s)
- Anupamjeet Kaur
- Department of Chemistry
- Faculty of Basic and Applied Sciences
- Sri Guru Granth Sahib World University
- Fatehgarh Sahib-140406
- India
| | - Suniba Shuaib
- Department of Chemistry
- Faculty of Basic and Applied Sciences
- Sri Guru Granth Sahib World University
- Fatehgarh Sahib-140406
- India
| | - Deepti Goyal
- Department of Chemistry
- Faculty of Basic and Applied Sciences
- Sri Guru Granth Sahib World University
- Fatehgarh Sahib-140406
- India
| | - Bhupesh Goyal
- School of Chemistry & Biochemistry
- Thapar Institute of Engineering & Technology
- Patiala-147004
- India
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79
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Wallin C, Friedemann M, Sholts SB, Noormägi A, Svantesson T, Jarvet J, Roos PM, Palumaa P, Gräslund A, Wärmländer SKTS. Mercury and Alzheimer's Disease: Hg(II) Ions Display Specific Binding to the Amyloid-β Peptide and Hinder Its Fibrillization. Biomolecules 2019; 10:E44. [PMID: 31892131 PMCID: PMC7022868 DOI: 10.3390/biom10010044] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 02/07/2023] Open
Abstract
Brains and blood of Alzheimer's disease (AD) patients have shown elevated mercury concentrations, but potential involvement of mercury exposure in AD pathogenesis has not been studied at the molecular level. The pathological hallmark of AD brains is deposition of amyloid plaques, consisting mainly of amyloid-β (Aβ) peptides aggregated into amyloid fibrils. Aβ peptide fibrillization is known to be modulated by metal ions such as Cu(II) and Zn(II). Here, we study in vitro the interactions between Aβ peptides and Hg(II) ions by multiple biophysical techniques. Fluorescence spectroscopy and atomic force microscopy (AFM) show that Hg(II) ions have a concentration-dependent inhibiting effect on Aβ fibrillization: at a 1:1 Aβ·Hg(II) ratio only non-fibrillar Aβ aggregates are formed. NMR spectroscopy shows that Hg(II) ions interact with the N-terminal region of Aβ(1-40) with a micromolar affinity, likely via a binding mode similar to that for Cu(II) and Zn(II) ions, i.e., mainly via the histidine residues His6, His13, and His14. Thus, together with Cu(II), Fe(II), Mn(II), Pb(IV), and Zn(II) ions, Hg(II) belongs to a family of metal ions that display residue-specific binding interactions with Aβ peptides and modulate their aggregation processes.
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Affiliation(s)
- Cecilia Wallin
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden; (C.W.); (T.S.); (J.J.); (A.G.)
| | - Merlin Friedemann
- Department of Chemistry and Biotechnology, Tallinn University of Technology, 19086 Tallinn, Estonia; (M.F.); (A.N.); (P.P.)
| | - Sabrina B. Sholts
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA;
| | - Andra Noormägi
- Department of Chemistry and Biotechnology, Tallinn University of Technology, 19086 Tallinn, Estonia; (M.F.); (A.N.); (P.P.)
| | - Teodor Svantesson
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden; (C.W.); (T.S.); (J.J.); (A.G.)
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden; (C.W.); (T.S.); (J.J.); (A.G.)
- The National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Per M. Roos
- Institute of Environmental Medicine, Karolinska Institutet, 16765 Stockholm, Sweden;
- Department of Clinical Physiology, Capio St. Göran Hospital, 11219 Stockholm, Sweden
| | - Peep Palumaa
- Department of Chemistry and Biotechnology, Tallinn University of Technology, 19086 Tallinn, Estonia; (M.F.); (A.N.); (P.P.)
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden; (C.W.); (T.S.); (J.J.); (A.G.)
| | - Sebastian K. T. S. Wärmländer
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden; (C.W.); (T.S.); (J.J.); (A.G.)
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80
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Yu L, Li DW, Brüschweiler R. Balanced Amino-Acid-Specific Molecular Dynamics Force Field for the Realistic Simulation of Both Folded and Disordered Proteins. J Chem Theory Comput 2019; 16:1311-1318. [DOI: 10.1021/acs.jctc.9b01062] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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81
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Sahoo BR, Bekier ME, Liu Z, Kocman V, Stoddard AK, Anantharamaiah GM, Nowick J, Fierke CA, Wang Y, Ramamoorthy A. Structural Interaction of Apolipoprotein A-I Mimetic Peptide with Amyloid-β Generates Toxic Hetero-oligomers. J Mol Biol 2019; 432:1020-1034. [PMID: 31866295 DOI: 10.1016/j.jmb.2019.12.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/27/2019] [Accepted: 12/01/2019] [Indexed: 01/21/2023]
Abstract
Apolipoproteins are involved in pathological conditions of Alzheimer's disease (AD), and it has been reported that truncated apolipoprotein fragments and β-amyloid (Aβ) peptides coexist as neurotoxic heteromers within the plaques. Therefore, it is important to investigate these complexes at the molecular level to better understand their properties and roles in the pathology of AD. Here, we present a mechanistic insight into such heteromerization using a structurally homologue apolipoprotein fragment of apoA-I (4F) complexed with Aβ(M1-42) and characterize their toxicity. The 4F peptide slows down the aggregation kinetics of Aβ(M1-42) by constraining its structural plasticity. NMR and CD experiments identified 4F-Aβ(M1-42) heteromers comprised of unstructured Aβ(M1-42) and helical 4F. A uniform two-fold reduction in 15N/1H NMR signal intensities of Aβ(M1-42) with no observable chemical shift perturbation indicated the formation of a large complex, which was further confirmed by diffusion NMR experiments. Microsecond-scale atomistic molecular dynamics simulations showed that 4F interaction with Aβ(M1-42) is electrostatically driven and induces unfolding of Aβ(M1-42). Neurotoxicity profiling of Aβ(M1-42) complexed with 4F confirms a significant reduction in cell viability and neurite growth. Thus, the molecular architecture of heteromerization between 4F and Aβ(M1-42) discovered in this study provides evidence toward our understanding of the role of apolipoproteins or their truncated fragments in exacerbating AD pathology.
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Affiliation(s)
- Bikash Ranjan Sahoo
- Biophysics and Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Michael E Bekier
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1085, USA
| | - Zichen Liu
- Biophysics and Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Vojc Kocman
- Biophysics and Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Andrea K Stoddard
- Biophysics and Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - G M Anantharamaiah
- Department of Medicine, University of Alabama at Birmingham Medical Center, Birmingham, AL, 35294, USA
| | - James Nowick
- Department of Chemistry, University of California-Irvine, Irvine, CA, 92697-2025, USA
| | - Carol A Fierke
- Department of Chemistry, University of Texas A&M, College Station, TX, 77843-3255, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1085, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, 48109-1055, USA.
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82
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Liu H, Song D, Zhang Y, Yang S, Luo R, Chen HF. Extensive tests and evaluation of the CHARMM36IDPSFF force field for intrinsically disordered proteins and folded proteins. Phys Chem Chem Phys 2019; 21:21918-21931. [PMID: 31552948 DOI: 10.1039/c9cp03434j] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Intrinsically disordered proteins (IDPs) have received increasing attention in recent studies due to their structural heterogeneity and critical biological functions. To fully understand the structural properties and determine accurate ensembles of IDPs, molecular dynamics (MD) simulation was widely used to sample diverse conformations and reveal the structural dynamics. However, the classical state-of-the-art force fields perform well for folded proteins while being unsatisfactory for the simulations of disordered proteins reported in many previous studies. Thus, improved force fields were developed to precisely describe both folded proteins and disordered proteins. Preliminary tests show that our newly developed CHARMM36IDPSFF (C36IDPSFF) force field can well reproduce the experimental observables of several disordered proteins, but more tests on different types of proteins are needed to further evaluate the performance of C36IDPSFF. Here, we extensively simulate short peptides, disordered proteins, and fast-folding proteins as well as folded proteins, and compare the simulated results with the experimental observables. The simulation results show that C36IDPSFF could substantially reproduce the experimental observables for most of the tested proteins but some limitations are also found in the radius of gyration of large disordered proteins and the stability of fast-folding proteins. This force field will facilitate large scale studies of protein structural dynamics and functions using MD simulations.
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Affiliation(s)
- Hao Liu
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, SJTU-Yale Joint Center for Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
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83
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Yang S, Liu H, Zhang Y, Lu H, Chen H. Residue-Specific Force Field Improving the Sample of Intrinsically Disordered Proteins and Folded Proteins. J Chem Inf Model 2019; 59:4793-4805. [DOI: 10.1021/acs.jcim.9b00647] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sheng Yang
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, SJTU−Yale Joint Center for Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Hao Liu
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, SJTU−Yale Joint Center for Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Yangpeng Zhang
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, SJTU−Yale Joint Center for Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Hui Lu
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, SJTU−Yale Joint Center for Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
- SJTU-Yale Joint Center for Biostatistics and Data Science, 800 Dongchuan Road, Shanghai, 200240, China
| | - Haifeng Chen
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, SJTU−Yale Joint Center for Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
- Shanghai Center for Bioinformation Technology, 1278 Keyuan Road, Shanghai, 200235, China
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84
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Hashemi M, Zhang Y, Lv Z, Lyubchenko YL. Spontaneous self-assembly of amyloid β (1-40) into dimers. NANOSCALE ADVANCES 2019; 1:3892-3899. [PMID: 36132110 PMCID: PMC9417245 DOI: 10.1039/c9na00380k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/16/2019] [Indexed: 05/17/2023]
Abstract
The self-assembly and fibrillation of amyloid β (Aβ) proteins is the neuropathological hallmark of Alzheimer's disease. However, the molecular mechanism of how disordered monomers assemble into aggregates remains largely unknown. In this work, we characterize the assembly of Aβ (1-40) monomers into dimers using long-time molecular dynamics simulations. Upon interaction, the monomers undergo conformational transitions, accompanied by change of the structure, leading to the formation of a stable dimer. The dimers are stabilized by interactions in the N-terminal region (residues 5-12), in the central hydrophobic region (residues 16-23), and in the C-terminal region (residues 30-40); with inter-peptide interactions focused around the N- and C-termini. The dimers do not contain long β-strands that are usually found in fibrils.
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Affiliation(s)
- Mohtadin Hashemi
- Department of Pharmaceutical Sciences, 986025 Nebraska Medical Center, University of Nebraska Medical Center Omaha NE 68198 USA
| | - Yuliang Zhang
- Department of Pharmaceutical Sciences, 986025 Nebraska Medical Center, University of Nebraska Medical Center Omaha NE 68198 USA
- Biology and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory Livermore CA 94550 USA
| | - Zhengjian Lv
- Department of Pharmaceutical Sciences, 986025 Nebraska Medical Center, University of Nebraska Medical Center Omaha NE 68198 USA
- Bruker Nano Surfaces Division 112 Robin Hill Road Goleta, Santa Barbara CA 93117 USA
| | - Yuri L Lyubchenko
- Department of Pharmaceutical Sciences, 986025 Nebraska Medical Center, University of Nebraska Medical Center Omaha NE 68198 USA
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85
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Liang C, Savinov SN, Fejzo J, Eyles SJ, Chen J. Modulation of Amyloid-β42 Conformation by Small Molecules Through Nonspecific Binding. J Chem Theory Comput 2019; 15:5169-5174. [PMID: 31476124 DOI: 10.1021/acs.jctc.9b00599] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Aggregation of amyloid-β (Aβ) peptides is a crucial step in the progression of Alzheimer's disease (AD). Identifying aggregation inhibitors against AD has been a great challenge. We report an atomistic simulation study of the inhibition mechanism of two small molecules, homotaurine and scyllo-inositol, which are AD drug candidates currently under investigation. We show that both small molecules promote a conformational change of the Aβ42 monomer toward a more collapsed phase through a nonspecific binding mechanism. This finding provides atomistic-level insights into designing potential drug candidates for future AD treatments.
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Affiliation(s)
- Chungwen Liang
- Computational Modeling Core Facility, Institute for Applied Life Sciences (IALS) , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
| | - Sergey N Savinov
- Computational Modeling Core Facility, Institute for Applied Life Sciences (IALS) , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States.,Department of Biochemistry and Molecular Biology , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
| | - Jasna Fejzo
- Biomolecular NMR Core Facility, Institute for Applied Life Sciences (IALS) , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
| | - Stephen J Eyles
- Mass Spectrometry Core Facility, Institute for Applied Life Sciences (IALS) , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
| | - Jianhan Chen
- Department of Biochemistry and Molecular Biology , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States.,Department of Chemistry , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
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86
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Ying J, Barnes CA, Louis JM, Bax A. Importance of time-ordered non-uniform sampling of multi-dimensional NMR spectra of Aβ 1-42 peptide under aggregating conditions. JOURNAL OF BIOMOLECULAR NMR 2019; 73:429-441. [PMID: 31407200 PMCID: PMC6819256 DOI: 10.1007/s10858-019-00235-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 02/09/2019] [Indexed: 06/02/2023]
Abstract
Although the order of the time steps in which the non-uniform sampling (NUS) schedule is implemented when acquiring multi-dimensional NMR spectra is of limited importance when sample conditions remain unchanged over the course of the experiment, it is shown to have major impact when samples are unstable. In the latter case, time-ordering of the NUS data points by the normalized radial length yields a reduction of sampling artifacts, regardless of the spectral reconstruction algorithm. The disadvantage of time-ordered NUS sampling is that halting the experiment prior to its completion will result in lower spectral resolution, rather than a sparser data matrix. Alternatively, digitally correcting for sample decay prior to reconstruction of randomly ordered NUS data points can mitigate reconstruction artifacts, at the cost of somewhat lower sensitivity. Application of these sampling schemes to the Alzheimer's amyloid beta (Aβ1-42) peptide at an elevated concentration, low temperature, and 3 kbar of pressure, where approximately 75% of the peptide reverts to an NMR-invisible state during the collection of a 3D 15N-separated NOESY spectrum, highlights the improvement in artifact suppression and reveals weak medium-range NOE contacts in several regions, including the C-terminal region of the peptide.
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Affiliation(s)
- Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - C Ashley Barnes
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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87
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Lin Y, Sahoo BR, Ozawa D, Kinoshita M, Kang J, Lim MH, Okumura M, Huh YH, Moon E, Jang JH, Lee HJ, Ryu KY, Ham S, Won HS, Ryu KS, Sugiki T, Bang JK, Hoe HS, Fujiwara T, Ramamoorthy A, Lee YH. Diverse Structural Conversion and Aggregation Pathways of Alzheimer's Amyloid-β (1-40). ACS NANO 2019; 13:8766-8783. [PMID: 31310506 DOI: 10.1021/acsnano.9b01578] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Complex amyloid aggregation of amyloid-β (1-40) (Aβ1-40) in terms of monomer structures has not been fully understood. Herein, we report the microscopic mechanism and pathways of Aβ1-40 aggregation with macroscopic viewpoints through tuning its initial structure and solubility. Partial helical structures of Aβ1-40 induced by low solvent polarity accelerated cytotoxic Aβ1-40 amyloid fibrillation, while predominantly helical folds did not aggregate. Changes in the solvent polarity caused a rapid formation of β-structure-rich protofibrils or oligomers via aggregation-prone helical structures. Modulation of the pH and salt concentration transformed oligomers to protofibrils, which proceeded to amyloid formation. We reveal diverse molecular mechanisms underlying Aβ1-40 aggregation with conceptual energy diagrams and propose that aggregation-prone partial helical structures are key to inducing amyloidogenesis. We demonstrate that context-dependent protein aggregation is comprehensively understood using the macroscopic phase diagram, which provides general insights into differentiation of amyloid formation and phase separation from unfolded and folded structures.
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Affiliation(s)
- Yuxi Lin
- Department of Chemistry , Sookmyung Women's University , Cheongpa-ro 47-gil 100 , Yongsan-gu, Seoul 04310 , South Korea
| | - Bikash R Sahoo
- Biophysics Program and Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Daisaku Ozawa
- Department of Neurotherapeutics , Osaka University Graduate School of Medicine , 2-2 Yamadaoka , Suita , Osaka 565-0871 , Japan
| | - Misaki Kinoshita
- Frontier Research Institute for Interdisciplinary Sciences , Tohoku University , 6-3 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8578 , Japan
| | - Juhye Kang
- Department of Chemistry , Korea Advanced Institute of Science and Technology , Daejeon 34141 , South Korea
- Department of Chemistry , Ulsan National Institute of Science and Technology , Ulsan 44919 , South Korea
| | - Mi Hee Lim
- Department of Chemistry , Korea Advanced Institute of Science and Technology , Daejeon 34141 , South Korea
| | - Masaki Okumura
- Frontier Research Institute for Interdisciplinary Sciences , Tohoku University , 6-3 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8578 , Japan
| | | | | | | | - Hyun-Ju Lee
- Department of Neural Development and Disease , Korea Brain Research Institute , 61 Cheomdan-ro , Dong-gu, Daegu 41068 , South Korea
| | - Ka-Young Ryu
- Department of Neural Development and Disease , Korea Brain Research Institute , 61 Cheomdan-ro , Dong-gu, Daegu 41068 , South Korea
| | - Sihyun Ham
- Department of Chemistry , Sookmyung Women's University , Cheongpa-ro 47-gil 100 , Yongsan-gu, Seoul 04310 , South Korea
| | - Hyung-Sik Won
- Department of Biotechnology, Research Institute and College of Biomedical and Health Science , Konkuk University , Chungju , Chungbuk 27478 , South Korea
| | | | - Toshihiko Sugiki
- Institute for Protein Research , Osaka University , Yamadaoka 3-2 , Suita , Osaka 565-0871 , Japan
| | | | - Hyang-Sook Hoe
- Department of Neural Development and Disease , Korea Brain Research Institute , 61 Cheomdan-ro , Dong-gu, Daegu 41068 , South Korea
| | - Toshimichi Fujiwara
- Institute for Protein Research , Osaka University , Yamadaoka 3-2 , Suita , Osaka 565-0871 , Japan
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Young-Ho Lee
- Institute for Protein Research , Osaka University , Yamadaoka 3-2 , Suita , Osaka 565-0871 , Japan
- Bio-Analytical Science , University of Science and Technology , Daejeon 34113 , South Korea
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88
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Posado-Fernández A, Afonso CF, Dória G, Flores O, Cabrita EJ. Epitope Mapping by NMR of a Novel Anti-Aβ Antibody (STAB-MAb). Sci Rep 2019; 9:12241. [PMID: 31439854 PMCID: PMC6706428 DOI: 10.1038/s41598-019-47626-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 07/19/2019] [Indexed: 11/17/2022] Open
Abstract
Alzheimer´s Disease (AD) is one of the most common neurodegenerative disorders worldwide. Excess of β-amyloid (Aβ), a peptide with a high propensity to misfold and self-aggregate, is believed to be the major contributor to the observed neuronal degeneration and cognitive decline in AD. Here, we characterize the epitope of a novel anti-Aβ monoclonal antibody, the STAB-MAb, which has previously demonstrated picomolar affinities for both monomers (KD = 80 pM) and fibrils (KD = 130 pM) of Aβ(1–42) and has shown therapeutic efficacy in preclinical mouse models of AD. Our findings reveal a widespread epitope that embraces several key Aβ residues that have been previously described as important in the Aβ fibrillation process. Of note, STAB-MAb exhibits a stronger affinity for the N-terminus of Aβ and stabilizes an α-helix conformation in the central to N-terminal region of the peptide, in addition to disrupting a characteristic salt-bridge of a hairpin structure present in fibrils. The NMR derived epitope supports the observed results from ThT-monitored fluorescence and electron microscopy experiments, in which STAB-MAb was shown to inhibit the formation of aggregates and promote disruption of pre-formed fibrils. In combination with the published in vitro and in vivo assays, our study highlights STAB-MAb as a rare and versatile antibody with analytical, diagnostic and therapeutic efficacy.
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Affiliation(s)
- Adrián Posado-Fernández
- UCIBIO, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-516, Caparica, Portugal.,STAB VIDA Lda., Madan Parque, Rua dos Inventores, 2825-182, Caparica, Portugal
| | - Cláudia F Afonso
- UCIBIO, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-516, Caparica, Portugal.,Instituto de Medicina Molecular (iMM), Avenida Professor Egas Moniz, 1649-028, Lisboa, Portugal
| | - Gonçalo Dória
- STAB VIDA Lda., Madan Parque, Rua dos Inventores, 2825-182, Caparica, Portugal
| | - Orfeu Flores
- STAB VIDA Lda., Madan Parque, Rua dos Inventores, 2825-182, Caparica, Portugal
| | - Eurico J Cabrita
- UCIBIO, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-516, Caparica, Portugal.
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89
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LeVatte MA, Lipfert M, Ladner-Keay C, Wishart DS. Preparation and characterization of a highly soluble Aβ 1-42 peptide variant. Protein Expr Purif 2019; 164:105480. [PMID: 31425755 DOI: 10.1016/j.pep.2019.105480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/11/2019] [Accepted: 08/15/2019] [Indexed: 01/04/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurological disease marked by the accumulation and deposition of misfolded amyloid beta or Abeta (Aβ) peptide. Two species of Aβ peptides are found in amyloid plaques, Aβ1-40 and Aβ1-42, with the latter being the more amyloidogenic of the two. Understanding how and why Aβ peptides misfold, oligomerize and form amyloid plaques requires a detailed understanding of their structure and dynamics. The poor solubility and strong aggregation tendencies of Aβ1-42 has made the isolation and characterization of its different structural isoforms (monomer, dimer, oligomer, amyloid) exceedingly difficult. Furthermore, while synthetic Aβ1-42 peptides (Aβ42syn) are readily available, the cost of isotopically labeled peptide is substantial, making their characterization by NMR spectroscopy cost prohibitive. Here we describe the design, cloning, high-level production, isotopic labeling and biophysical characterization of a modified (solubility-tagged) Aβ1-42 variant that exhibits excellent water solubility and shares similar aggregation properties as wildtype Aβ1-42. Specifically, we attached six lysines (6K) to the C-terminus of native Aβ1-42 to create a more soluble, monomeric form of Aβ1-42 called Aβ42C6K. A gene for the Aβ42C6K was designed, synthesized and cloned into Escherichia coli (E. coli) and the peptide was expressed at milligram levels. The Aβ42C6K peptide was characterized using circular dichroism (CD), NMR, electron microscopy and thioflavin T fluorescence. Its ability to form stable monomers, oligomers and fibrils under different conditions was assessed. Our results indicate that Aβ42C6K stays monomeric at high concentrations (unlike Aβ1-42) and can be induced to oligomerize and form fibrils like Aβ1-42. Our novel construct could be used to explore the structure and dynamics of Aβ1-42 as well as the interaction of ligands with Aβ1-42 via NMR.
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Affiliation(s)
- Marcia A LeVatte
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E8, Canada
| | - Matthias Lipfert
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E8, Canada
| | - Carol Ladner-Keay
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E8, Canada
| | - David S Wishart
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E8, Canada; Department of Computing Science, University of Alberta, Edmonton, AB, T6G 2E8, Canada.
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90
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Zerze GH, Stillinger FH, Debenedetti PG. Computational investigation of retro-isomer equilibrium structures: Intrinsically disordered, foldable, and cyclic peptides. FEBS Lett 2019; 594:104-113. [PMID: 31356683 DOI: 10.1002/1873-3468.13558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 06/20/2019] [Accepted: 07/26/2019] [Indexed: 11/08/2022]
Abstract
We use all-atom modeling and advanced-sampling molecular dynamics simulations to investigate quantitatively the effect of peptide bond directionality on the equilibrium structures of four linear (two foldable, two disordered) and two cyclic peptides. We find that the retro forms of cyclic and foldable linear peptides adopt distinctively different conformations compared to their parents. While the retro form of a linear intrinsically disordered peptide with transient secondary structure fails to reproduce a secondary structure content similar to that of its parent, the retro form of a shorter disordered linear peptide shows only minor differences compared to its parent.
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Affiliation(s)
- Gül H Zerze
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | | | - Pablo G Debenedetti
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
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91
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Penke B, Bogár F, Paragi G, Gera J, Fülöp L. Key Peptides and Proteins in Alzheimer's Disease. Curr Protein Pept Sci 2019; 20:577-599. [PMID: 30605056 DOI: 10.2174/1389203720666190103123434] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/03/2018] [Accepted: 12/27/2018] [Indexed: 02/02/2023]
Abstract
Alzheimer's Disease (AD) is a form of progressive dementia involving cognitive impairment, loss of learning and memory. Different proteins (such as amyloid precursor protein (APP), β- amyloid (Aβ) and tau protein) play a key role in the initiation and progression of AD. We review the role of the most important proteins and peptides in AD pathogenesis. The structure, biosynthesis and physiological role of APP are shortly summarized. The details of trafficking and processing of APP to Aβ, the cytosolic intracellular Aβ domain (AICD) and small soluble proteins are shown, together with other amyloid-forming proteins such as tau and α-synuclein (α-syn). Hypothetic physiological functions of Aβ are summarized. The mechanism of conformational change, the formation and the role of neurotoxic amyloid oligomeric (oAβ) are shown. The fibril formation process and the co-existence of different steric structures (U-shaped and S-shaped) of Aβ monomers in mature fibrils are demonstrated. We summarize the known pathogenic and non-pathogenic mutations and show the toxic interactions of Aβ species after binding to cellular receptors. Tau phosphorylation, fibrillation, the molecular structure of tau filaments and their toxic effect on microtubules are shown. Development of Aβ and tau imaging in AD brain and CSF as well as blood biomarkers is shortly summarized. The most probable pathomechanisms of AD including the toxic effects of oAβ and tau; the three (biochemical, cellular and clinical) phases of AD are shown. Finally, the last section summarizes the present state of Aβ- and tau-directed therapies and future directions of AD research and drug development.
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Affiliation(s)
- Botond Penke
- Department of Medical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dom square 8, Szeged, H-6720, Hungary
| | - Ferenc Bogár
- Department of Medical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dom square 8, Szeged, H-6720, Hungary.,MTA-SZTE Biomimetic Systems Research Group, University of Szeged, H-6720 Szeged, Dom square 8, Hungary
| | - Gábor Paragi
- MTA-SZTE Biomimetic Systems Research Group, University of Szeged, H-6720 Szeged, Dom square 8, Hungary.,Institute of Physics, University of Pécs, H-7624 Pecs, Ifjusag utja 6, Hungary
| | - János Gera
- Department of Medical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dom square 8, Szeged, H-6720, Hungary
| | - Lívia Fülöp
- Department of Medical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dom square 8, Szeged, H-6720, Hungary
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92
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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: 119] [Impact Index Per Article: 23.8] [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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93
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Nguyen PH, Campanera JM, Ngo ST, Loquet A, Derreumaux P. Tetrameric Aβ40 and Aβ42 β-Barrel Structures by Extensive Atomistic Simulations. II. In Aqueous Solution. J Phys Chem B 2019; 123:6750-6756. [DOI: 10.1021/acs.jpcb.9b05288] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Phuong H. Nguyen
- CNRS, Université de Paris, UPR 9080,
Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
- Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Josep M. Campanera
- Departament de Fisicoquímica, Facultat de Farmacia, Universitat de Barcelona, 08028 Barcelona, Catalonia, Spain
| | - Son Tung Ngo
- Laboratory of Theoretical and Computational Biophysics, Ton Duc Thang University, Ho Chi Minh City, Vietnam
- Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Antoine Loquet
- Institute of Chemistry and Biology of Membranes and Nanoobjects, UMR5248 CNRS, Université de Bordeaux, Bordeaux, 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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94
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Bhattacharya S, Xu L, Thompson D. Molecular Simulations Reveal Terminal Group Mediated Stabilization of Helical Conformers in Both Amyloid-β42 and α-Synuclein. ACS Chem Neurosci 2019; 10:2830-2842. [PMID: 30917651 DOI: 10.1021/acschemneuro.9b00053] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The presence of partially structured helices in natively unfolded amyloid-β42 (Aβ42) and α-synuclein (αS) has been shown to accelerate fibrillation in the onset of Alzheimer's and Parkinson's disease, respectively. At the other extreme, folded stable helical conformers have also been reported to resist amyloid formation. Recent studies indicate that amyloidogenic aggregation can be impeded using small molecules that stabilize the α-helical monomers and switch off the neurotoxic pathway. We predict a common intrapeptide route to stabilization based on the plasticity of helical conformations of Aβ42 and αS as assessed through extensive atomistic molecular dynamics (MD) computer simulations (∼36 μs) across ten distinct protein force field and water model combinations. Computed free energies and interaction maps (not obtainable from experiments alone) show that flexible terminal groups (N-terminus of Aβ42 and C-terminus of αS) show a tendency to stabilize folded helical conformations in both peptides via primary hydrophobic interactions with central hydrophobic domains, and secondary salt bridges with other domains. These interactions confer aggregation resistance by decreasing the population of partially structured helices and are absent in control simulations of complete unfolding. Computed helical stability is also significantly reduced in terminal-deleted variants. The models suggest new strategies to tackle neurodegeneration by rationally re-engineering terminal groups to optimize their predicted ability to deactivate helical monomers.
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Affiliation(s)
- Shayon Bhattacharya
- Department of Physics, Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland
| | - Liang Xu
- Department of Physics, Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland
| | - Damien Thompson
- Department of Physics, Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland
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95
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Arispe N, De Maio A. Memory Loss and the Onset of Alzheimer's Disease Could Be Under the Control of Extracellular Heat Shock Proteins. J Alzheimers Dis 2019; 63:927-934. [PMID: 29689729 DOI: 10.3233/jad-180161] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Alzheimer's disease (AD) is a major contemporary and escalating malady in which amyloid-β (Aβ) peptides are the most likely causative agent. Aβ peptides spontaneously tend to aggregate in extracellular fluids following a progression from a monomeric state, through intermediate forms, ending in amyloid fibers and plaques. It is generally accepted now that the neurotoxic agents leading to cellular death, memory loss, and other AD characteristics are the Aβ intermediate aggregated states. However, Aβ peptides are continuously produced, released into the extracellular space, and rapidly cleared from healthy brains. Coincidentally, members of the heat shock proteins (hsp) family are present in the extracellular medium of healthy cells and body fluids, opening the possibility that hsps and Aβ could meet and interact in the extracellular milieu of the brain. In this perspective and reflection article, we place our investigation showing that the presence of Hsp70s mitigate the formation of low molecular weight Aβ peptide oligomers resulting in a reduction of cellular toxicity, in context of the current understanding of the disease. We propose that it may be an inverse relationship between the presence of Hsp70, the stage of Aβ oligomers, neurotoxicity, and the incidence of AD, particularly since the expression and circulating levels of hsp decrease with aging. Combining these observations, we propose that changes in the dynamics of Hsp70s and Aβ concentrations in the circulating brain fluids during aging defines the control of the formation of Aβ toxic aggregates, thus determining the conditions for neuron degeneration and the incidence of AD.
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Affiliation(s)
- Nelson Arispe
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Antonio De Maio
- Department of Surgery and Neurosciences, University of California, San Diego, School of Medicine, La Jolla, CA, USA
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96
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Zhang T, Loschwitz J, Strodel B, Nagel-Steger L, Willbold D. Interference with Amyloid-β Nucleation by Transient Ligand Interaction. Molecules 2019; 24:E2129. [PMID: 31195746 PMCID: PMC6600523 DOI: 10.3390/molecules24112129] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/02/2019] [Accepted: 06/04/2019] [Indexed: 12/20/2022] Open
Abstract
Amyloid-β peptide (Aβ) is an intrinsically disordered protein (IDP) associated with Alzheimer's disease. The structural flexibility and aggregation propensity of Aβ pose major challenges for elucidating the interaction between Aβ monomers and ligands. All-D-peptides consisting solely of D-enantiomeric amino acid residues are interesting drug candidates that combine high binding specificity with high metabolic stability. Here we characterized the interaction between the 12-residue all-D-peptide D3 and Aβ42 monomers, and how the interaction influences Aβ42 aggregation. We demonstrate for the first time that D3 binds to Aβ42 monomers with submicromolar affinities. These two highly unstructured molecules are able to form complexes with 1:1 and other stoichiometries. Further, D3 at substoichiometric concentrations effectively slows down the β-sheet formation and Aβ42 fibrillation by modulating the nucleation process. The study provides new insights into the molecular mechanism of how D3 affects Aβ assemblies and contributes to our knowledge on the interaction between two IDPs.
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Affiliation(s)
- Tao Zhang
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany.
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
| | - Jennifer Loschwitz
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany.
- Institute of Theoretical and Computational Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
| | - Birgit Strodel
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany.
- Institute of Theoretical and Computational Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
| | - Luitgard Nagel-Steger
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany.
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
| | - Dieter Willbold
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany.
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
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97
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Efficient construction of a diverse conformational library for amyloid-β as an intrinsically disordered protein. J Mol Graph Model 2019; 88:183-193. [DOI: 10.1016/j.jmgm.2019.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 01/11/2019] [Accepted: 01/16/2019] [Indexed: 12/16/2022]
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98
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Lincoff J, Sasmal S, Head-Gordon T. The combined force field-sampling problem in simulations of disordered amyloid-β peptides. J Chem Phys 2019; 150:104108. [PMID: 30876367 DOI: 10.1063/1.5078615] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular dynamics simulations of intrinsically disordered proteins (IDPs) can provide high resolution structural ensembles if the force field is accurate enough and if the simulation sufficiently samples the conformational space of the IDP with the correct weighting of sub-populations. Here, we investigate the combined force field-sampling problem by testing a standard force field as well as newer fixed charge force fields, the latter specifically motivated for better description of unfolded states and IDPs, and comparing them with a standard temperature replica exchange (TREx) protocol and a non-equilibrium Temperature Cool Walking (TCW) sampling algorithm. The force field and sampling combinations are used to characterize the structural ensembles of the amyloid-beta peptides Aβ42 and Aβ43, which both should be random coils as shown recently by experimental nuclear magnetic resonance (NMR) and 2D Förster resonance energy transfer (FRET) experiments. The results illustrate the key importance of the sampling algorithm: while the standard force field using TREx is in poor agreement with the NMR J-coupling and nuclear Overhauser effect and 2D FRET data, when using the TCW method, the standard and optimized protein-water force field combinations are in very good agreement with the same experimental data since the TCW sampling method produces qualitatively different ensembles than TREx. We also discuss the relative merit of the 2D FRET data when validating structural ensembles using the different force fields and sampling protocols investigated in this work for small IDPs such as the Aβ42 and Aβ43 peptides.
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Affiliation(s)
- James Lincoff
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, USA
| | - Sukanya Sasmal
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, USA
| | - Teresa Head-Gordon
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, USA
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99
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Shabane PS, Izadi S, Onufriev AV. General Purpose Water Model Can Improve Atomistic Simulations of Intrinsically Disordered Proteins. J Chem Theory Comput 2019; 15:2620-2634. [PMID: 30865832 DOI: 10.1021/acs.jctc.8b01123] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Unconstrained atomistic simulations of intrinsically disordered proteins and peptides (IDP) remain a challenge: widely used, "general purpose" water models tend to favor overly compact structures relative to experiment. Here we have performed a total of 93 μs of unrestrained MD simulations to explore, in the context of IDPs, a recently developed "general-purpose" 4-point rigid water model OPC, which describes liquid state of water close to experiment. We demonstrate that OPC, together with a popular AMBER force field ff99SB, offers a noticeable improvement over TIP3P in producing more realistic structural ensembles of three common IDPs benchmarks: 55-residue apo N-terminal zinc-binding domain of HIV-1 integrase ("protein IN"), amyloid β-peptide (Aβ42) (residues 1-42), and 26-reside H4 histone tail. As a negative control, computed folding profile of a regular globular miniprotein (CLN025) in OPC water is in appreciably better agreement with experiment than that obtained in TIP3P, which tends to overstabilize the compact native state relative to the extended conformations. We employed Aβ42 peptide to investigate the possible influence of the solvent box size on simulation outcomes. We advocate a cautious approach for simulations of IDPs: we suggest that the solvent box size should be at least four times the radius of gyration of the random coil corresponding to the IDP. The computed free energy landscape of protein IN in OPC resembles a shallow "tub" - conformations with substantially different degrees of compactness that are within 2 kB T of each other. Conformations with very different secondary structure content coexist within 1 kB T of the global free energy minimum. States with higher free energy tend to have less secondary structure. Computed low helical content of the protein has virtually no correlation with its degree of compactness, which calls into question the possibility of using the helicity as a metric for assessing performance of water models for IDPs, when the helicity is low. Predicted radius of gyration ( R g) of H4 histone tail in OPC water falls in-between that of a typical globular protein and a fully denatured protein of the same size; the predicted R g is consistent with two independent predictions. In contrast, H4 tail in TIP3P water is as compact as the corresponding globular protein. The computed free energy landscape of H4 tail in OPC is relatively flat over a significant range of compactness, which, we argue, is consistent with its biological function as facilitator of internucleosome interactions.
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Affiliation(s)
| | - Saeed Izadi
- Early Stage Pharmaceutical Development , Genentech Inc. , South San Francisco , California 94080 , United States
| | - Alexey V Onufriev
- Department of Computer Science , Virginia Tech , Blacksburg , Virginia 24060 , United States.,Center for Soft Matter and Biological Physics , Virginia Tech , Blacksburg , Virginia 24061 , United States
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Mudedla SK, Murugan NA, Ågren H. Effect of Familial Mutations on the Interconversion of α-Helix to β-Sheet Structures in an Amyloid-Forming Peptide: Insight from Umbrella Sampling Simulations. ACS Chem Neurosci 2019; 10:1347-1354. [PMID: 30586502 DOI: 10.1021/acschemneuro.8b00425] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Understanding the initial events of aggregation of amyloid β monomers to form β-sheet rich fibrils is useful for the development of therapeutics for Alzheimer's disease. In this context, the changes in energetics involved in the aggregation of helical amyloid β monomers into β-sheet rich dimers have been investigated using umbrella sampling simulations and density functional theory calculations. The results from umbrella sampling simulations for the free energy profile for the interconversion closely agree with the results of density functional theory calculations. The results reveal that helical peptides converted to β-sheet structures through coil-like conformations as intermediates that are mostly stabilized by intramolecular hydrogen bonds. The stabilization of intermediate structures could be a possible way to inhibit fibril formation. Mutations substantially decrease the height of the energy barrier for interconversion from α-helix to β-sheet structure when compared to that of the wild type, something that is attributed to an increase in the number of intramolecular hydrogen bonds between backbone atoms in the coil structures that correspond to a maximum value on the free energy surface. The reduction of the energy barrier leads to an enhancement of the rate of aggregation of amyloid β monomers upon introduction of various familial mutations, which is consistent with previous experimental reports.
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Affiliation(s)
- Sathish Kumar Mudedla
- Division of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Center, Royal Institute of Technology (KTH), S-106 91 Stockholm, Sweden
| | - N. Arul Murugan
- Division of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Center, Royal Institute of Technology (KTH), S-106 91 Stockholm, Sweden
| | - Hans Ågren
- Division of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Center, Royal Institute of Technology (KTH), S-106 91 Stockholm, Sweden
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, P. R. China
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