1
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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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2
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Hutchison JM, Shih KC, Scheidt HA, Fantin SM, Parson KF, Pantelopulos GA, Harrington HR, Mittendorf KF, Qian S, Stein RA, Collier SE, Chambers MG, Katsaras J, Voehler MW, Ruotolo BT, Huster D, McFeeters RL, Straub JE, Nieh MP, Sanders CR. Bicelles Rich in both Sphingolipids and Cholesterol and Their Use in Studies of Membrane Proteins. J Am Chem Soc 2020; 142:12715-12729. [PMID: 32575981 DOI: 10.1021/jacs.0c04669] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
How the distinctive lipid composition of mammalian plasma membranes impacts membrane protein structure is largely unexplored, partly because of the dearth of isotropic model membrane systems that contain abundant sphingolipids and cholesterol. This gap is addressed by showing that sphingomyelin and cholesterol-rich (SCOR) lipid mixtures with phosphatidylcholine can be cosolubilized by n-dodecyl-β-melibioside to form bicelles. Small-angle X-ray and neutron scattering, as well as cryo-electron microscopy, demonstrate that these assemblies are stable over a wide range of conditions and exhibit the bilayered-disc morphology of ideal bicelles even at low lipid-to-detergent mole ratios. SCOR bicelles are shown to be compatible with a wide array of experimental techniques, as applied to the transmembrane human amyloid precursor C99 protein in this medium. These studies reveal an equilibrium between low-order oligomer structures that differ significantly from previous experimental structures of C99, providing an example of how ordered membranes alter membrane protein structure.
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Affiliation(s)
- James M Hutchison
- Chemical and Physical Biology Graduate Program and Center for Structural Biology, Vanderbilt University, Nashville 37240, Tennessee, United States
| | - Kuo-Chih Shih
- Polymer Program, Department of Chemical & Biomolecular Engineering, and Department of Biomedical Engineering, University of Connecticut, Storrs 06269, Connecticut, United States
| | - Holger A Scheidt
- Institute for Medical Physics and Biophysics, Leipzig University, Leipzig 16-18, 04107, Germany
| | - Sarah M Fantin
- Department of Chemistry, University of Michigan, Ann Arbor 48109, Michigan, United States
| | - Kristine F Parson
- Department of Chemistry, University of Michigan, Ann Arbor 48109, Michigan, United States
| | - George A Pantelopulos
- Department of Chemistry, Boston University, Boston 02215, Massachusetts, United States
| | - Haley R Harrington
- Center for Structural Biology and Department of Biochemistry, Vanderbilt University School of Medicine Basic Sciences, Nashville 37240, Tennessee, United States
| | - Kathleen F Mittendorf
- Center for Health Research, Kaiser Permanente, Portland 97227, Oregon, United States
| | - Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge 37831, Tennessee, United States
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville37240, Tennessee, United States
| | - Scott E Collier
- Department of Translational and Applied Genomics, Center for Health Research, Kaiser Permanente Northwest, Portland 97227, Oregon, United States
| | - Melissa G Chambers
- Center for Structural Biology, Vanderbilt University, Nashville 37240, Tennessee, United States
| | - John Katsaras
- Neutron Scattering Division and Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge 37831, Tennessee, United States
| | - Markus W Voehler
- Center for Structural Biology and Department of Chemistry, Vanderbilt University, Nashville 37240, Tennessee, United States
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor 48109, Michigan, United States
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Leipzig University, Leipzig 16-18, 04107, Germany
| | - Robert L McFeeters
- Department of Chemistry, University of Alabama, Huntsville 35899, Alabama, United States
| | - John E Straub
- Department of Chemistry, Boston University, Boston 02215, Massachusetts, United States
| | - Mu-Ping Nieh
- Polymer Program, Department of Chemical & Biomolecular Engineering, and Department of Biomedical Engineering, University of Connecticut, Storrs 06269, Connecticut, United States
| | - Charles R Sanders
- Center for Structural Biology, Department of Biochemistry, and Department of Medicine, Vanderbilt University School of Medicine, Nashville 37240, Tennessee, United States
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3
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Effects of an HIV-1 maturation inhibitor on the structure and dynamics of CA-SP1 junction helices in virus-like particles. Proc Natl Acad Sci U S A 2020; 117:10286-10293. [PMID: 32341150 DOI: 10.1073/pnas.1917755117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
HIV-1 maturation involves conversion of the immature Gag polyprotein lattice, which lines the inner surface of the viral membrane, to the mature capsid protein (CA) lattice, which encloses the viral RNA. Maturation inhibitors such as bevirimat (BVM) bind within six-helix bundles, formed by a segment that spans the junction between the CA and spacer peptide 1 (SP1) subunits of Gag, and interfere with cleavage between CA and SP1 catalyzed by the HIV-1 protease (PR). We report solid-state NMR (ssNMR) measurements on spherical virus-like particles (VLPs), facilitated by segmental isotopic labeling, that provide information about effects of BVM on the structure and dynamics of CA-SP1 junction helices in the immature lattice. Although BVM strongly blocks PR-catalyzed CA-SP1 cleavage in VLPs and blocks conversion of VLPs to tubular CA assemblies, 15N and 13C ssNMR chemical shifts of segmentally labeled VLPs with and without BVM are very similar, indicating that interaction with BVM does not alter the six-helix bundle structure appreciably. Only the 15N chemical shift of A280 (the first residue of SP1) changes significantly, consistent with BVM binding to an internal ring of hydrophobic side chains of L279 residues. Measurements of transverse 15N spin relaxation rates reveal a reduction in the amplitudes and/or timescales of backbone N-H bond motions, corresponding to a rigidification of the six-helix bundles. Overall, our data show that inhibition of HIV-1 maturation by BVM involves changes in structure and dynamics that are surprisingly subtle, but still sufficient to produce a large effect on CA-SP1 cleavage.
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Wi S, Frydman L. An Efficient, Robust New Scheme for Establishing Broadband Homonuclear Correlations in Biomolecular Solid State NMR. Chemphyschem 2020; 21:284-294. [DOI: 10.1002/cphc.201901071] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/17/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Sungsool Wi
- National High Magnetic Field Laboratory Tallahassee Florida 32304 USA
| | - Lucio Frydman
- National High Magnetic Field Laboratory Tallahassee Florida 32304 USA
- Department of Chemical and Biological Physics Weizmann Institute of Sciences Rehovot Israel
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5
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Scharfenberg F, Armbrust F, Marengo L, Pietrzik C, Becker-Pauly C. Regulation of the alternative β-secretase meprin β by ADAM-mediated shedding. Cell Mol Life Sci 2019; 76:3193-3206. [PMID: 31201463 PMCID: PMC11105663 DOI: 10.1007/s00018-019-03179-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 05/23/2019] [Accepted: 05/29/2019] [Indexed: 12/12/2022]
Abstract
Alzheimer's Disease (AD) is the sixth-leading cause of death in industrialized countries. Neurotoxic amyloid-β (Aβ) plaques are one of the pathological hallmarks in AD patient brains. Aβ accumulates in the brain upon sequential, proteolytic processing of the amyloid precursor protein (APP) by β- and γ-secretases. However, so far disease-modifying drugs targeting β- and γ-secretase pathways seeking a decrease in the production of toxic Aβ peptides have failed in clinics. It has been demonstrated that the metalloproteinase meprin β acts as an alternative β-secretase, capable of generating truncated Aβ2-x peptides that have been described to be increased in AD patients. This indicates an important β-site cleaving enzyme 1 (BACE-1)-independent contribution of the metalloprotease meprin β within the amyloidogenic pathway and may lead to novel drug targeting avenues. However, meprin β itself is embedded in a complex regulatory network. Remarkably, the anti-amyloidogenic α-secretase a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) is a direct competitor for APP at the cell surface, but also a sheddase of inactive pro-meprin β. Overall, we highlight the current cellular, molecular and structural understanding of meprin β as alternative β-secretase within the complex protease web, regulating APP processing in health and disease.
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Affiliation(s)
- Franka Scharfenberg
- Unit for Degradomics of the Protease Web, Biochemical Institute, University of Kiel, Kiel, Germany
| | - Fred Armbrust
- Unit for Degradomics of the Protease Web, Biochemical Institute, University of Kiel, Kiel, Germany
| | - Liana Marengo
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Claus Pietrzik
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Christoph Becker-Pauly
- Unit for Degradomics of the Protease Web, Biochemical Institute, University of Kiel, Kiel, Germany.
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6
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Götz A, Högel P, Silber M, Chaitoglou I, Luy B, Muhle-Goll C, Scharnagl C, Langosch D. Increased H-Bond Stability Relates to Altered ε-Cleavage Efficiency and Aβ Levels in the I45T Familial Alzheimer's Disease Mutant of APP. Sci Rep 2019; 9:5321. [PMID: 30926830 PMCID: PMC6440955 DOI: 10.1038/s41598-019-41766-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 02/27/2019] [Indexed: 12/15/2022] Open
Abstract
Cleavage of the amyloid precursor protein's (APP) transmembrane domain (TMD) by γ-secretase is a crucial step in the aetiology of Alzheimer's Disease (AD). Mutations in the APP TMD alter cleavage and lead to familial forms of AD (FAD). The majority of FAD mutations shift the preference of initial cleavage from ε49 to ε48, thus raising the AD-related Aβ42/Aβ40 ratio. The I45T mutation is among the few FAD mutations that do not alter ε-site preference, while it dramatically reduces the efficiency of ε-cleavage. Here, we investigate the impact of the I45T mutation on the backbone dynamics of the substrate TMD. Amide exchange experiments and molecular dynamics simulations in solvent and a lipid bilayer reveal an increased stability of amide hydrogen bonds at the ζ- and γ-cleavage sites. Stiffening of the H-bond network is caused by an additional H-bond between the T45 side chain and the TMD backbone, which alters dynamics within the cleavage domain. In particular, the increased H-bond stability inhibits an upward movement of the ε-sites in the I45T mutant. Thus, an altered presentation of ε-sites to the active site of γ-secretase as a consequence of restricted local flexibility provides a rationale for reduced ε-cleavage efficiency of the I45T mutant.
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Grants
- Deutsche Forschungsgemeinschaft (German Research Foundation)
- Helmholtz-Gemeinschaft (Helmholtz Association)
- Leibniz Supercomputing Centre: Leibniz-Rechenzentrum der Bayerischen Akademie der Wissenschaften, Boltzmannstraße 1, 85748 Garching bei München, Germany, WEB: https://www.lrz.de Gauss Centre for Supercomputing: GCS-Geschäftsstelle Bonn, Ahrstrasse 45, 53175 Bonn, Germany, WEB: http://www.gauss-centre.eu
- Center for Integrated Protein Science: Munich Center For Integrated Protein Science (CIPSM), Butenandtstr. 5 - 13, 81377 Munich, Germany, WEB: http://www.cipsm.de/ Leibniz Supercomputing Centre: Leibniz-Rechenzentrum der Bayerischen Akademie der Wissenschaften, Boltzmannstraße 1, 85748 Garching bei München, Germany, WEB: https://www.lrz.de
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Affiliation(s)
- Alexander Götz
- Lehrstuhl für Physik synthetischer Biosysteme (E14), Technische Universität München, Maximus-von-Imhof Forum 4, 85354, Freising, Germany
| | - Philipp Högel
- Center for Integrated Protein Science Munich (CIPSM) at the Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany
| | - Mara Silber
- Institute of Organic Chemistry and Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Iro Chaitoglou
- Center for Integrated Protein Science Munich (CIPSM) at the Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany
| | - Burkhard Luy
- Institute of Organic Chemistry and Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Claudia Muhle-Goll
- Institute of Organic Chemistry and Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Christina Scharnagl
- Lehrstuhl für Physik synthetischer Biosysteme (E14), Technische Universität München, Maximus-von-Imhof Forum 4, 85354, Freising, Germany.
| | - Dieter Langosch
- Center for Integrated Protein Science Munich (CIPSM) at the Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany.
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7
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Corradi V, Sejdiu BI, Mesa-Galloso H, Abdizadeh H, Noskov SY, Marrink SJ, Tieleman DP. Emerging Diversity in Lipid-Protein Interactions. Chem Rev 2019; 119:5775-5848. [PMID: 30758191 PMCID: PMC6509647 DOI: 10.1021/acs.chemrev.8b00451] [Citation(s) in RCA: 245] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Membrane
lipids interact with proteins in a variety of ways, ranging
from providing a stable membrane environment for proteins to being
embedded in to detailed roles in complicated and well-regulated protein
functions. Experimental and computational advances are converging
in a rapidly expanding research area of lipid–protein interactions.
Experimentally, the database of high-resolution membrane protein structures
is growing, as are capabilities to identify the complex lipid composition
of different membranes, to probe the challenging time and length scales
of lipid–protein interactions, and to link lipid–protein
interactions to protein function in a variety of proteins. Computationally,
more accurate membrane models and more powerful computers now enable
a detailed look at lipid–protein interactions and increasing
overlap with experimental observations for validation and joint interpretation
of simulation and experiment. Here we review papers that use computational
approaches to study detailed lipid–protein interactions, together
with brief experimental and physiological contexts, aiming at comprehensive
coverage of simulation papers in the last five years. Overall, a complex
picture of lipid–protein interactions emerges, through a range
of mechanisms including modulation of the physical properties of the
lipid environment, detailed chemical interactions between lipids and
proteins, and key functional roles of very specific lipids binding
to well-defined binding sites on proteins. Computationally, despite
important limitations, molecular dynamics simulations with current
computer power and theoretical models are now in an excellent position
to answer detailed questions about lipid–protein interactions.
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Affiliation(s)
- Valentina Corradi
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Besian I Sejdiu
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Haydee Mesa-Galloso
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Haleh Abdizadeh
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - Sergei Yu Noskov
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
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Li CD, Junaid M, Chen H, Ali A, Wei DQ. Helix-Switch Enables C99 Dimer Transition between the Multiple Conformations. J Chem Inf Model 2019; 59:339-350. [PMID: 30570254 DOI: 10.1021/acs.jcim.8b00559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
C99 is the immediate precursor of amyloid-β (Aβ) and therefore is a central intermediate in the pathway that is believed to result in Alzheimer's disease (AD). Recent studies have shown that C99 dimerization changes the Aβ ratio, but the mechanism remains unclear. Previous studies of the C99 dimer have produced controversial structure models. To address these questions, we investigated C99 dimerization using molecular dynamics (MD) simulations. A helix-switch model was revealed in the formation and transition of the C99 dimer, and six types of conformations were identified. The different conformations show differential exposures of γ-cleavage sites and insertion depths in the bilayer, which may modulate γ-cleavage of C99 and lead to different Aβ levels. Our results redefine C99 dimerization, provide a framework to mediate the current controversial results, and give insights into the understanding of the relationship between C99 dimerization and Aβ formation.
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Affiliation(s)
- Cheng-Dong Li
- State Key Laboratory of Microbial Metabolism and College of Life Sciences and Biotechnology , Shanghai Jiao Tong University , Minhang District, Shanghai 200240 , China.,Department of Mechanical Engineering and Material Science , Yale University , New Haven , Connecticut 06520-8286 , United States
| | - Muhammad Junaid
- State Key Laboratory of Microbial Metabolism and College of Life Sciences and Biotechnology , Shanghai Jiao Tong University , Minhang District, Shanghai 200240 , China
| | - Hui Chen
- State Key Laboratory of Microbial Metabolism and College of Life Sciences and Biotechnology , Shanghai Jiao Tong University , Minhang District, Shanghai 200240 , China
| | - Arif Ali
- State Key Laboratory of Microbial Metabolism and College of Life Sciences and Biotechnology , Shanghai Jiao Tong University , Minhang District, Shanghai 200240 , China
| | - Dong-Qing Wei
- State Key Laboratory of Microbial Metabolism and College of Life Sciences and Biotechnology , Shanghai Jiao Tong University , Minhang District, Shanghai 200240 , China
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9
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Clemente N, Abdine A, Ubarretxena-Belandia I, Wang C. Coupled Transmembrane Substrate Docking and Helical Unwinding in Intramembrane Proteolysis of Amyloid Precursor Protein. Sci Rep 2018; 8:12411. [PMID: 30120254 PMCID: PMC6098081 DOI: 10.1038/s41598-018-30015-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/23/2018] [Indexed: 12/03/2022] Open
Abstract
Intramembrane-cleaving proteases (I-CLiPs) play crucial roles in physiological and pathological processes, such as Alzheimer’s disease and cancer. However, the mechanisms of substrate recognition by I-CLiPs remain poorly understood. The aspartic I-CLiP presenilin is the catalytic subunit of the γ-secretase complex, which releases the amyloid-β peptides (Aβs) through intramembrane proteolysis of the transmembrane domain of the amyloid precursor protein (APPTM). Here we used solution NMR to probe substrate docking of APPTM to the presenilin homologs (PSHs) MCMJR1 and MAMRE50, which cleaved APPTM in the NMR tube. Chemical shift perturbation (CSP) showed juxtamembrane regions of APPTM mediate its docking to MCMJR1. Binding of the substrate to I-CLiP decreased the magnitude of amide proton chemical shifts δH at the C-terminal half of the substrate APPTM, indicating that the docking to the enzyme weakens helical hydrogen bonds and unwinds the substrate transmembrane helix around the initial ε-cleavage site. The APPTM V44M substitution linked to familial AD caused more CSP and helical unwinding around the ε-cleavage site. MAMRE50, which cleaved APPTM at a higher rate, also caused more CSP and helical unwinding in APPTM than MCMJR1. Our data suggest that docking of the substrate transmembrane helix and helical unwinding is coupled in intramembrane proteolysis and FAD mutation modifies enzyme/substrate interaction, providing novel insights into the mechanisms of I-CLiPs and AD drug discovery.
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Affiliation(s)
- Nicolina Clemente
- Biochemistry and Biophysics Graduate Program, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, 12180, USA
| | - Alaa Abdine
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Iban Ubarretxena-Belandia
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.,Biofisika Institute (CSIC, UPV/EHU), Universidad del País Vasco (UPV/EHU), E-48940, Leioa, Spain
| | - Chunyu Wang
- Biochemistry and Biophysics Graduate Program, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, 12180, USA. .,Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, 12180, USA.
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10
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Götz A, Scharnagl C. Dissecting conformational changes in APP's transmembrane domain linked to ε-efficiency in familial Alzheimer's disease. PLoS One 2018; 13:e0200077. [PMID: 29966005 PMCID: PMC6028146 DOI: 10.1371/journal.pone.0200077] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/19/2018] [Indexed: 02/02/2023] Open
Abstract
The mechanism by which familial Alzheimer's disease (FAD) mutations within the transmembrane domain (TMD) of the Amyloid Precursor Protein (APP) affect ε-endoproteolysis is only poorly understood. Thereby, mutations in the cleavage domain reduce ε-efficiency of γ-secretase cleavage and some even shift entry into production lines. Since cleavage occurs within the TMD, a relationship between processing and TMD structure and dynamics seems obvious. Using molecular dynamic simulations, we dissect the dynamic features of wild-type and seven FAD-mutants into local and global components. Mutations consistently enhance hydrogen-bond fluctuations upstream of the ε-cleavage sites but maintain strong helicity there. Dynamic perturbation-response scanning reveals that FAD-mutants target backbone motions utilized in the bound state. Those motions, obscured by large-scale motions in the pre-bound state, provide (i) a dynamic mechanism underlying the proposed coupling between binding and ε-cleavage, (ii) key sites consistent with experimentally determined docking sites, and (iii) the distinction between mutants and wild-type.
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Affiliation(s)
- Alexander Götz
- Technical University of Munich, Chair of Physics of Synthetic Biological Systems, Freising, Germany
| | - Christina Scharnagl
- Technical University of Munich, Chair of Physics of Synthetic Biological Systems, Freising, Germany
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11
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Itkin A, Salnikov ES, Aisenbrey C, Raya J, Glattard E, Raussens V, Ruysschaert JM, Bechinger B. Structural Characterization of the Amyloid Precursor Protein Transmembrane Domain and Its γ-Cleavage Site. ACS OMEGA 2017; 2:6525-6534. [PMID: 31457253 PMCID: PMC6645296 DOI: 10.1021/acsomega.7b00619] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/16/2017] [Indexed: 06/10/2023]
Abstract
Alzheimer's disease is the most common form of dementia that affects about 50 million of sufferers worldwide. A major role for the initiation and progression of Alzheimer's disease has been associated with the amyloid β-peptide (Aβ), which is a protease cleavage product of the amyloid precursor protein. The amyloid precursor protein is an integral membrane protein with a single transmembrane domain. Here, we assessed the structural integrity of the transmembrane domain within oriented phosphatidylcholine lipid bilayers and determined the tilt angle distribution and dynamics of various subdomains using solid-state NMR and attenuated total reflectance Fourier transform infrared spectroscopies. Although the overall secondary structure of the transmembrane domain is α-helical, pronounced conformational and topological heterogeneities were observed for the γ- and, to a lesser extent, the ζ-cleavage site, with pronounced implications for the production of Aβ and related peptides, the development of the disease, and pharmaceutical innovation.
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Affiliation(s)
- Anna Itkin
- University
of Strasbourg/CNRS, UMR7177 Chemistry Institute, Membrane Biophysics
and NMR, 4, rue Blaise
Pascal, F-67070 Strasbourg, France
- Center
for Structural Biology and Bioinformatics, Laboratory of Structure
and Function of Biological Membranes, Université
Libre de Bruxelles, Campus
Plaine - Acces 2 - Batiment BC - Niveau 4, Boulevard du Triomphe -
CP 206/2, B-1050 Brussels, Belgium
| | - Evgeniy S. Salnikov
- University
of Strasbourg/CNRS, UMR7177 Chemistry Institute, Membrane Biophysics
and NMR, 4, rue Blaise
Pascal, F-67070 Strasbourg, France
| | - Christopher Aisenbrey
- University
of Strasbourg/CNRS, UMR7177 Chemistry Institute, Membrane Biophysics
and NMR, 4, rue Blaise
Pascal, F-67070 Strasbourg, France
| | - Jesus Raya
- University
of Strasbourg/CNRS, UMR7177 Chemistry Institute, Membrane Biophysics
and NMR, 4, rue Blaise
Pascal, F-67070 Strasbourg, France
| | - Elise Glattard
- University
of Strasbourg/CNRS, UMR7177 Chemistry Institute, Membrane Biophysics
and NMR, 4, rue Blaise
Pascal, F-67070 Strasbourg, France
| | - Vincent Raussens
- Center
for Structural Biology and Bioinformatics, Laboratory of Structure
and Function of Biological Membranes, Université
Libre de Bruxelles, Campus
Plaine - Acces 2 - Batiment BC - Niveau 4, Boulevard du Triomphe -
CP 206/2, B-1050 Brussels, Belgium
| | - Jean-Marie Ruysschaert
- Center
for Structural Biology and Bioinformatics, Laboratory of Structure
and Function of Biological Membranes, Université
Libre de Bruxelles, Campus
Plaine - Acces 2 - Batiment BC - Niveau 4, Boulevard du Triomphe -
CP 206/2, B-1050 Brussels, Belgium
| | - Burkhard Bechinger
- University
of Strasbourg/CNRS, UMR7177 Chemistry Institute, Membrane Biophysics
and NMR, 4, rue Blaise
Pascal, F-67070 Strasbourg, France
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12
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Cao Z, Hutchison JM, Sanders CR, Bowie JU. Backbone Hydrogen Bond Strengths Can Vary Widely in Transmembrane Helices. J Am Chem Soc 2017; 139:10742-10749. [PMID: 28692798 PMCID: PMC5560243 DOI: 10.1021/jacs.7b04819] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
![]()
Although
backbone hydrogen bonds in transmembrane (TM) helices
have the potential to be very strong due to the low dielectric and
low water environment of the membrane, their strength has never been
assessed experimentally. Moreover, variations in hydrogen bond strength
might be necessary to facilitate the TM helix breaking and bending
that is often needed to satisfy functional imperatives. Here we employed
equilibrium hydrogen/deuterium fractionation factors to measure backbone
hydrogen bond strengths in the TM helix of the amyloid precursor protein
(APP). We find an enormous range of hydrogen bond free energies, with
some weaker than water–water hydrogen bonds and some over 6
kcal/mol stronger than water–water hydrogen bonds. We find
that weak hydrogen bonds are at or near preferred γ-secretase
cleavage sites, suggesting that the sequence of APP and possibly other
cleaved TM helices may be designed, in part, to make their backbones
accessible for cleavage. The finding that hydrogen bond strengths
in a TM helix can vary widely has implications for membrane protein
function, dynamics, evolution, and design.
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Affiliation(s)
- Zheng Cao
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California , Los Angeles, California 90095, United States
| | - James M Hutchison
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Charles R Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - James U Bowie
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California , Los Angeles, California 90095, United States
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13
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Sun F, Chen L, Wei P, Chai M, Ding X, Xu L, Luo SZ. Dimerization and Structural Stability of Amyloid Precursor Proteins Affected by the Membrane Microenvironments. J Chem Inf Model 2017; 57:1375-1387. [DOI: 10.1021/acs.jcim.7b00196] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fude Sun
- Beijing Key Laboratory of
Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Long Chen
- Beijing Key Laboratory of
Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Peng Wei
- Beijing Key Laboratory of
Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Mengya Chai
- Beijing Key Laboratory of
Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiufang Ding
- Beijing Key Laboratory of
Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Lida Xu
- Beijing Key Laboratory of
Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Shi-Zhong Luo
- Beijing Key Laboratory of
Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
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14
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Expression, Functional Characterization, and Solid-State NMR Investigation of the G Protein-Coupled GHS Receptor in Bilayer Membranes. Sci Rep 2017; 7:46128. [PMID: 28387359 PMCID: PMC5384189 DOI: 10.1038/srep46128] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 03/13/2017] [Indexed: 01/14/2023] Open
Abstract
The expression, functional reconstitution and first NMR characterization of the human growth hormone secretagogue (GHS) receptor reconstituted into either DMPC or POPC membranes is described. The receptor was expressed in E. coli. refolded, and reconstituted into bilayer membranes. The molecule was characterized by 15N and 13C solid-state NMR spectroscopy in the absence and in the presence of its natural agonist ghrelin or an inverse agonist. Static 15N NMR spectra of the uniformly labeled receptor are indicative of axially symmetric rotational diffusion of the G protein-coupled receptor in the membrane. In addition, about 25% of the 15N sites undergo large amplitude motions giving rise to very narrow spectral components. For an initial quantitative assessment of the receptor mobility, 1H-13C dipolar coupling values, which are scaled by molecular motions, were determined quantitatively. From these values, average order parameters, reporting the motional amplitudes of the individual receptor segments can be derived. Average backbone order parameters were determined with values between 0.56 and 0.69, corresponding to average motional amplitudes of 40–50° of these segments. Differences between the receptor dynamics in DMPC or POPC membranes were within experimental error. Furthermore, agonist or inverse agonist binding only insignificantly influenced the average molecular dynamics of the receptor.
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15
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Sato T. Chemical synthesis of transmembrane peptide and its application for research on the transmembrane-juxtamembrane region of membrane protein. Biopolymers 2017; 106:613-21. [PMID: 26573237 DOI: 10.1002/bip.22775] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 12/11/2022]
Abstract
Membrane proteins possess one or more hydrophobic regions that span the membrane and interact with the lipids that constitute the membrane. The interactions between the transmembrane (TM) region and lipids affect the structure and function of these membrane proteins. Molecular characterization of synthetic TM peptides in lipid bilayers helps to understand how the TM region participates in the formation of the structure and in the function of membrane proteins. The use of synthetic peptides enables site-specific labeling and modification and allows for designing of an artificial TM sequence. Research involving such samples has resulted in significant increase in the knowledge of the mechanisms that govern membrane biology. In this review, the chemical synthesis of TM peptides has been discussed. The preparation of synthetic TM peptides is still not trivial; however, the accumulated knowledge summarized here should provide a basis for preparing samples for spectroscopic analyses. The application of synthetic TM peptides for gaining insights into the mechanism of signal transduction by receptor tyrosine kinase (RTK) has also been discussed. RTK is a single TM protein and is one of the difficult targets in structural biology as crystallization of the full-length receptor has not been successful. This review describes the structural characterization of the synthetic TM-juxtamembrane sequence and proposes a possible scheme for the structural changes in this region for the activation of ErbBs, the epidermal growth factor receptor family. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 613-621, 2016.
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Affiliation(s)
- Takeshi Sato
- Laboratory of Protein Organic Chemistry, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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16
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Impact of membrane lipid composition on the structure and stability of the transmembrane domain of amyloid precursor protein. Proc Natl Acad Sci U S A 2016; 113:E5281-7. [PMID: 27559086 DOI: 10.1073/pnas.1606482113] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cleavage of the amyloid precursor protein (APP) by γ-secretase is a crucial first step in the evolution of Alzheimer's disease. To discover the cleavage mechanism, it is urgent to predict the structures of APP monomers and dimers in varying membrane environments. We determined the structures of the C9923-55 monomer and homodimer as a function of membrane lipid composition using a multiscale simulation approach that blends atomistic and coarse-grained models. We demonstrate that the C9923-55 homodimer structures form a heterogeneous ensemble with multiple conformational states, each stabilized by characteristic interpeptide interactions. The relative probabilities of each conformational state are sensitive to the membrane environment, leading to substantial variation in homodimer peptide structure as a function of membrane lipid composition or the presence of an anionic lipid environment. In contrast, the helicity of the transmembrane domain of monomeric C991-55 is relatively insensitive to the membrane lipid composition, in agreement with experimental observations. The dimer structures of human EphA2 receptor depend on the lipid environment, which we show is linked to the location of the structural motifs in the dimer interface, thereby establishing that both sequence and membrane composition modulate the complete energy landscape of membrane-bound proteins. As a by-product of our work, we explain the discrepancy in structures predicted for C99 congener homodimers in membrane and micelle environments. Our study provides insight into the observed dependence of C99 protein cleavage by γ-secretase, critical to the formation of amyloid-β protein, on membrane thickness and lipid composition.
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17
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Structure of amyloid oligomers and their mechanisms of toxicities: Targeting amyloid oligomers using novel therapeutic approaches. Eur J Med Chem 2016; 114:41-58. [DOI: 10.1016/j.ejmech.2016.02.065] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 01/22/2023]
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18
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Chen W, Gamache E, Rosenman DJ, Xie J, Lopez MM, Li YM, Wang C. Familial Alzheimer's mutations within APPTM increase Aβ42 production by enhancing accessibility of ε-cleavage site. Nat Commun 2015; 5:3037. [PMID: 24390130 DOI: 10.1038/ncomms4037] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 11/29/2013] [Indexed: 02/08/2023] Open
Abstract
The high Aβ42/Aβ40 production ratio is a hallmark of familial Alzheimer's disease, which can be caused by mutations in the amyloid precursor protein (APP). The C-terminus of Aβ is generated by γ-secretase cleavage within the transmembrane domain of APP (APPTM), a process that is primed by an initial ε-cleavage at either T48 or L49, resulting in subsequent production of Aβ42 or Aβ40, respectively. Here we solve the dimer structures of wild-type APPTM (AAPTM WT) and mutant APPTM (FAD mutants V44M) with solution NMR. The right-handed APPTM helical dimer is mediated by GXXXA motif. From the NMR structural and dynamic data, we show that the V44M and V44A mutations can selectively expose the T48 site by weakening helical hydrogen bonds and increasing hydrogen-deuterium exchange rate (kex). We propose a structural model in which FAD mutations (V44M and V44A) can open the T48 site γ-secretase for the initial ε-cleavage, and consequently shift cleavage preference towards Aβ42.
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Affiliation(s)
- Wen Chen
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - Eric Gamache
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - David J Rosenman
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - Jian Xie
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - Maria M Lopez
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - Yue-Ming Li
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA
| | - Chunyu Wang
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
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19
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Viswanath S, Dominguez L, Foster LS, Straub JE, Elber R. Extension of a protein docking algorithm to membranes and applications to amyloid precursor protein dimerization. Proteins 2015; 83:2170-85. [PMID: 26404856 DOI: 10.1002/prot.24934] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/13/2015] [Accepted: 09/17/2015] [Indexed: 12/13/2022]
Abstract
Novel adjustments are introduced to the docking algorithm, DOCK/PIERR, for the purpose of predicting structures of transmembrane protein complexes. Incorporating knowledge about the membrane environment is shown to significantly improve docking accuracy. The extended version of DOCK/PIERR is shown to perform comparably to other leading docking packages. This membrane version of DOCK/PIERR is applied to the prediction of coiled-coil homodimer structures of the transmembrane region of the C-terminal peptide of amyloid precursor protein (C99). Results from MD simulation of the C99 homodimer in POPC bilayer and docking are compared. Docking results are found to capture key aspects of the homodimer ensemble, including the existence of three topologically distinct conformers. Furthermore, the extended version of DOCK/PIERR is successful in capturing the effects of solvation in membrane and micelle. Specifically, DOCK/PIERR reproduces essential differences in the homodimer ensembles simulated in POPC bilayer and DPC micelle, where configurational entropy and surface curvature effects bias the handedness and topology of the homodimer ensemble.
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Affiliation(s)
- Shruthi Viswanath
- Department of Computer Science, University of Texas at Austin, Austin, Texas, 78712.,Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas, 78712
| | - Laura Dominguez
- Department of Chemistry, Boston University, Boston, Massachusetts, 02215
| | - Leigh S Foster
- Department of Chemistry, Boston University, Boston, Massachusetts, 02215
| | - John E Straub
- Department of Chemistry, Boston University, Boston, Massachusetts, 02215
| | - Ron Elber
- Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas, 78712.,Department of Chemistry, University of Texas at Austin, Austin, Texas, 78712
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20
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Morishima-Kawashima M. Molecular mechanism of the intramembrane cleavage of the β-carboxyl terminal fragment of amyloid precursor protein by γ-secretase. Front Physiol 2014; 5:463. [PMID: 25505888 PMCID: PMC4245903 DOI: 10.3389/fphys.2014.00463] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 11/11/2014] [Indexed: 01/31/2023] Open
Abstract
Amyloid β-protein (Aβ) plays a central role in the pathogenesis of Alzheimer's disease, the most common age-associated neurodegenerative disorder. Aβ is generated through intramembrane proteolysis of the β-carboxyl terminal fragment (βCTF) of β-amyloid precursor protein (APP) by γ-secretase. The initial cleavage by γ-secretase occurs in the membrane/cytoplasm boundary of the βCTF, liberating the APP intracellular domain (AICD). The remaining βCTFs, which are truncated at the C-terminus (longer Aβs), are then cropped sequentially in a stepwise manner, predominantly at three residue intervals, to generate Aβ. There are two major Aβ product lines which generate Aβ40 and Aβ42 with concomitant release of three and two tripeptides, respectively. Additionally, many alternative cleavages occur, releasing peptides with three to six residues. These modulate the Aβ product lines and define the species and quantity of Aβ generated. Here, we review our current understanding of the intramembrane cleavage of the βCTF by γ-secretase, which may contribute to the future goal of developing an efficient therapeutic strategy for Alzheimer's disease.
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Affiliation(s)
- Maho Morishima-Kawashima
- Laboratory of Neuroscience, Graduate School of Pharmaceutical Sciences, Hokkaido University Sapporo, Japan
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21
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Scharnagl C, Pester O, Hornburg P, Hornburg D, Götz A, Langosch D. Side-chain to main-chain hydrogen bonding controls the intrinsic backbone dynamics of the amyloid precursor protein transmembrane helix. Biophys J 2014; 106:1318-26. [PMID: 24655507 DOI: 10.1016/j.bpj.2014.02.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 01/28/2014] [Accepted: 02/07/2014] [Indexed: 01/19/2023] Open
Abstract
Many transmembrane helices contain serine and/or threonine residues whose side chains form intrahelical H-bonds with upstream carbonyl oxygens. Here, we investigated the impact of threonine side-chain/main-chain backbonding on the backbone dynamics of the amyloid precursor protein transmembrane helix. This helix consists of a N-terminal dimerization region and a C-terminal cleavage region, which is processed by γ-secretase to a series of products. Threonine mutations within this transmembrane helix are known to alter the cleavage pattern, which can lead to early-onset Alzheimer's disease. Circular dichroism spectroscopy and amide exchange experiments of synthetic transmembrane domain peptides reveal that mutating threonine enhances the flexibility of this helix. Molecular dynamics simulations show that the mutations reduce intrahelical amide H-bonding and H-bond lifetimes. In addition, the removal of side-chain/main-chain backbonding distorts the helix, which alters bending and rotation at a diglycine hinge connecting the dimerization and cleavage regions. We propose that the backbone dynamics of the substrate profoundly affects the way by which the substrate is presented to the catalytic site within the enzyme. Changing this conformational flexibility may thus change the pattern of proteolytic processing.
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Affiliation(s)
| | - Oxana Pester
- Munich Center for Integrated Protein Science (CIPS(M)) at Lehrstuhl Chemie der Biopolymere, Technische Universität München, Freising, Germany
| | - Philipp Hornburg
- Fakultät für Physik E14, Technische Universität München, Freising, Germany
| | - Daniel Hornburg
- Fakultät für Physik E14, Technische Universität München, Freising, Germany
| | - Alexander Götz
- Munich Center for Integrated Protein Science (CIPS(M)) at Lehrstuhl Chemie der Biopolymere, Technische Universität München, Freising, Germany
| | - Dieter Langosch
- Munich Center for Integrated Protein Science (CIPS(M)) at Lehrstuhl Chemie der Biopolymere, Technische Universität München, Freising, Germany
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22
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Dominguez L, Foster L, Meredith SC, Straub JE, Thirumalai D. Structural heterogeneity in transmembrane amyloid precursor protein homodimer is a consequence of environmental selection. J Am Chem Soc 2014; 136:9619-26. [PMID: 24926593 PMCID: PMC4105063 DOI: 10.1021/ja503150x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The 99 amino acid C-terminal fragment of amyloid precursor protein (C99), consisting of a single transmembrane (TM) helix, is known to form homodimers. Homodimers can be processed by γ-secretase to produce amyloid-β (Aβ) protein, which is implicated in Alzheimer's disease (AD). While knowledge of the structure of C99 homodimers is of great importance, experimental NMR studies and simulations have produced varying structural models, including right-handed and left-handed coiled-coils. In order to investigate the structure of this critical protein complex, simulations of the C99(15-55) homodimer in POPC membrane bilayer and DPC surfactant micelle environments were performed using a multiscale approach that blends atomistic and coarse-grained models. The C99(15-55) homodimer adopts a dominant right-handed coiled-coil topology consisting of three characteristic structural states in a bilayer, only one of which is dominant in the micelle. Our structural study, which provides a self-consistent framework for understanding a number of experiments, shows that the energy landscape of the C99 homodimer supports a variety of slowly interconverting structural states. The relative importance of any given state can be modulated through environmental selection realized by altering the membrane or micelle characteristics.
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Affiliation(s)
- Laura Dominguez
- Department of Chemistry, Boston University , Boston, Massachusetts 02215, United States
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23
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Walsh P, Vanderlee G, Yau J, Campeau J, Sim VL, Yip CM, Sharpe S. The mechanism of membrane disruption by cytotoxic amyloid oligomers formed by prion protein(106-126) is dependent on bilayer composition. J Biol Chem 2014; 289:10419-10430. [PMID: 24554723 PMCID: PMC4036164 DOI: 10.1074/jbc.m113.515866] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 02/01/2014] [Indexed: 11/06/2022] Open
Abstract
The formation of fibrillar aggregates has long been associated with neurodegenerative disorders such as Alzheimer and Parkinson diseases. Although fibrils are still considered important to the pathology of these disorders, it is now widely understood that smaller amyloid oligomers are the toxic entities along the misfolding pathway. One characteristic shared by the majority of amyloid oligomers is the ability to disrupt membranes, a commonality proposed to be responsible for their toxicity, although the mechanisms linking this to cell death are poorly understood. Here, we describe the physical basis for the cytotoxicity of oligomers formed by the prion protein (PrP)-derived amyloid peptide PrP(106-126). We show that oligomers of this peptide kill several mammalian cells lines, as well as mouse cerebellar organotypic cultures, and we also show that they exhibit antimicrobial activity. Physical perturbation of model membranes mimicking bacterial or mammalian cells was investigated using atomic force microscopy, polarized total internal reflection fluorescence microscopy, and NMR spectroscopy. Disruption of anionic membranes proceeds through a carpet or detergent model as proposed for other antimicrobial peptides. By contrast, when added to zwitterionic membranes containing cholesterol-rich ordered domains, PrP(106-126) oligomers induce a loss of domain separation and decreased membrane disorder. Loss of raft-like domains may lead to activation of apoptotic pathways, resulting in cell death. This work sheds new light on the physical mechanisms of amyloid cytotoxicity and is the first to clearly show membrane type-specific modes of action for a cytotoxic peptide.
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Affiliation(s)
- Patrick Walsh
- Molecular Structure and Function Program, The Hospital for Sick Children, Toronto, Ontario M5G 1X8; Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8
| | - Gillian Vanderlee
- Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1
| | - Jason Yau
- Molecular Structure and Function Program, The Hospital for Sick Children, Toronto, Ontario M5G 1X8; Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8
| | - Jody Campeau
- Department of Medicine, Division of Neurology, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Valerie L Sim
- Department of Medicine, Division of Neurology, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Christopher M Yip
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8; Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1
| | - Simon Sharpe
- Molecular Structure and Function Program, The Hospital for Sick Children, Toronto, Ontario M5G 1X8; Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8.
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24
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Abstract
In this issue of Structure, Tang and colleagues probe how the Flemish mutation in amyloid precursor protein (APP) affects its conformation and cleavage by γ-secretase. They provide molecular insight into how an extracellular inhibitory element and cholesterol interactions affect the generation of Aβ peptides.
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Affiliation(s)
- Hsiang-Kai Lin
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Patrick C A van der Wel
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA.
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Chen L, Chen SH, Russell DH. An experimental study of the solvent-dependent self-assembly/disassembly and conformer preferences of gramicidin A. Anal Chem 2013; 85:7826-33. [PMID: 23855712 DOI: 10.1021/ac401370t] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The solvent dependence of self-assembly/disassembly kinetics and conformer preferences of the gramicidin A (GA) dimer is investigated using a combination of techniques, viz., electrospray ionization-ion mobility-mass spectrometry (IM-MS), collision-induced dissociation (CID), and hydrogen/deuterium exchange (HDX)-MS. IM-MS measurements reveal that there are possibly three distinct GA dimeric species, detected as sodium ion adduct ions [2GA + 2Na](2+), and these are assigned as the parallel β-helix, antiparallel β-helix, and head-to-head dimer. The monomerization kinetics and equilibrium abundances of the dimer ions depend upon solvent polarity. The antiparallel β-helix was the thermodynamically preferred species in less polar solvents. HDX measurements and collision-induced dissociation (CID) of the intermediate complex confirm the well-protected dimer geometry with strong intermolecular hydrogen bonds. This combined IM-HDX-CID methodology provides a comprehensive view of GA self-assembly/disassembly in low dielectric solutions, showing its potential utility in solving solution-phase protein self-assembly/disassembly kinetics and providing structural information of the multimers at the same time.
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Affiliation(s)
- Liuxi Chen
- Laboratory for Biological Mass Spectrometry, Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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Song Y, Hustedt EJ, Brandon S, Sanders CR. Competition between homodimerization and cholesterol binding to the C99 domain of the amyloid precursor protein. Biochemistry 2013; 52:5051-64. [PMID: 23865807 DOI: 10.1021/bi400735x] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The 99-residue transmembrane C-terminal domain (C99, also known as β-CTF) of the amyloid precursor protein (APP) is the product of the β-secretase cleavage of the full-length APP and is the substrate for γ-secretase cleavage. The latter cleavage releases the amyloid-β polypeptides that are closely associated with Alzheimer's disease. C99 is thought to form homodimers; however, the free energy in favor of dimerization has not previously been quantitated. It was also recently documented that cholesterol forms a 1:1 complex with monomeric C99 in bicelles. Here, the affinities for both homodimerization and cholesterol binding to C99 were measured in bilayered lipid vesicles using both electron paramagnetic resonance (EPR) and Förster resonance energy transfer (FRET) methods. Homodimerization and cholesterol binding were seen to be competitive processes that center on the transmembrane G₇₀₀XXXG₇₀₄XXXG₇₀₈ glycine-zipper motif and adjacent Gly709. On one hand, the observed Kd for cholesterol binding (Kd = 2.7 ± 0.3 mol %) is on the low end of the physiological cholesterol concentration range in mammalian cell membranes. On the other hand, the observed K(d) for homodimerization (K(d) = 0.47 ± 0.15 mol %) likely exceeds the physiological concentration range for C99. These results suggest that the 1:1 cholesterol/C99 complex will be more highly populated than C99 homodimers under most physiological conditions. These observations are of relevance for understanding the γ-secretase cleavage of C99.
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Affiliation(s)
- Yuanli Song
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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Pester O, Barrett PJ, Hornburg D, Hornburg P, Pröbstle R, Widmaier S, Kutzner C, Dürrbaum M, Kapurniotu A, Sanders CR, Scharnagl C, Langosch D. The backbone dynamics of the amyloid precursor protein transmembrane helix provides a rationale for the sequential cleavage mechanism of γ-secretase. J Am Chem Soc 2013; 135:1317-29. [PMID: 23265086 PMCID: PMC3560327 DOI: 10.1021/ja3112093] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The etiology of Alzheimer's disease depends on the relative abundance of different amyloid-β (Aβ) peptide species. These peptides are produced by sequential proteolytic cleavage within the transmembrane helix of the 99 residue C-terminal fragment of the amyloid precursor protein (C99) by the intramembrane protease γ-secretase. Intramembrane proteolysis is thought to require local unfolding of the substrate helix, which has been proposed to be cleaved as a homodimer. Here, we investigated the backbone dynamics of the substrate helix. Amide exchange experiments of monomeric recombinant C99 and of synthetic transmembrane domain peptides reveal that the N-terminal Gly-rich homodimerization domain exchanges much faster than the C-terminal cleavage region. MD simulations corroborate the differential backbone dynamics, indicate a bending motion at a diglycine motif connecting dimerization and cleavage regions, and detect significantly different H-bond stabilities at the initial cleavage sites. Our results are consistent with the following hypotheses about cleavage of the substrate: First, the GlyGly hinge may precisely position the substrate within γ-secretase such that its catalytic center must start proteolysis at the known initial cleavage sites. Second, the ratio of cleavage products formed by subsequent sequential proteolysis could be influenced by differential extents of solvation and by the stabilities of H-bonds at alternate initial sites. Third, the flexibility of the Gly-rich domain may facilitate substrate movement within the enzyme during sequential proteolysis. Fourth, dimerization may affect substrate processing by decreasing the dynamics of the dimerization region and by increasing that of the C-terminal part of the cleavage region.
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Affiliation(s)
- Oxana Pester
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Paul J. Barrett
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee USA 37232-8725
| | - Daniel Hornburg
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Philipp Hornburg
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Rasmus Pröbstle
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Simon Widmaier
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Christoph Kutzner
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Milena Dürrbaum
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Aphrodite Kapurniotu
- Fachgebiet Peptidbiochemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
| | - Charles R. Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee USA 37232-8725
| | - Christina Scharnagl
- Fakultät für Physik E14, Technische Universität München, Maximus-von-Imhof-Forum 4, 85354 Freising, Germany
| | - Dieter Langosch
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
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Tofoleanu F, Buchete NV. Alzheimer Aβ peptide interactions with lipid membranes: fibrils, oligomers and polymorphic amyloid channels. Prion 2012; 6:339-45. [PMID: 22874669 PMCID: PMC3609060 DOI: 10.4161/pri.21022] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Fibrillar aggregates of misfolded amyloid proteins are involved in a variety of diseases such as Alzheimer disease (AD), type 2 diabetes, Parkinson, Huntington and prion-related diseases. In the case of AD amyloid β (Aβ) peptides, the toxicity of amyloid oligomers and larger fibrillar aggregates is related to perturbing the biological function of the adjacent cellular membrane. We used atomistic molecular dynamics (MD) simulations of Aβ9–40 fibrillar oligomers modeled as protofilament segments, including lipid bilayers and explicit water molecules, to probe the first steps in the mechanism of Aβ-membrane interactions. Our study identified the electrostatic interaction between charged peptide residues and the lipid headgroups as the principal driving force that can modulate the further penetration of the C-termini of amyloid fibrils or fibrillar oligomers into the hydrophobic region of lipid membranes. These findings advance our understanding of the detailed molecular mechanisms and the effects related to Aβ-membrane interactions, and suggest a polymorphic structural character of amyloid ion channels embedded in lipid bilayers. While inter-peptide hydrogen bonds leading to the formation of β-strands may still play a stabilizing role in amyloid channel structures, these may also present a significant helical content in peptide regions (e.g., termini) that are subject to direct interactions with lipids rather than with neighboring Aβ peptides.
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Barrett PJ, Song Y, Van Horn WD, Hustedt EJ, Schafer JM, Hadziselimovic A, Beel AJ, Sanders CR. The amyloid precursor protein has a flexible transmembrane domain and binds cholesterol. Science 2012; 336:1168-71. [PMID: 22654059 PMCID: PMC3528355 DOI: 10.1126/science.1219988] [Citation(s) in RCA: 371] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
C99 is the transmembrane carboxyl-terminal domain of the amyloid precursor protein that is cleaved by γ-secretase to release the amyloid-β polypeptides, which are associated with Alzheimer's disease. Nuclear magnetic resonance and electron paramagnetic resonance spectroscopy show that the extracellular amino terminus of C99 includes a surface-embedded "N-helix" followed by a short "N-loop" connecting to the transmembrane domain (TMD). The TMD is a flexibly curved α helix, making it well suited for processive cleavage by γ-secretase. Titration of C99 reveals a binding site for cholesterol, providing mechanistic insight into how cholesterol promotes amyloidogenesis. Membrane-buried GXXXG motifs (G, Gly; X, any amino acid), which have an established role in oligomerization, were also shown to play a key role in cholesterol binding. The structure and cholesterol binding properties of C99 may aid in the design of Alzheimer's therapeutics.
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Affiliation(s)
- Paul J. Barrett
- Dept. of Biochemistry, Center for Structural Biology and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yuanli Song
- Dept. of Biochemistry, Center for Structural Biology and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Wade D. Van Horn
- Dept. of Biochemistry, Center for Structural Biology and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Eric J. Hustedt
- Dept. of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Johanna M. Schafer
- Dept. of Biochemistry, Center for Structural Biology and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Arina Hadziselimovic
- Dept. of Biochemistry, Center for Structural Biology and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Andrew J. Beel
- Dept. of Biochemistry, Center for Structural Biology and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Charles R. Sanders
- Dept. of Biochemistry, Center for Structural Biology and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Expression, purification, and reconstitution of the transmembrane domain of the human amyloid precursor protein for NMR studies. Protein Expr Purif 2011; 81:11-17. [PMID: 21907289 DOI: 10.1016/j.pep.2011.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 08/08/2011] [Accepted: 08/09/2011] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease (AD) is the most common type of dementia in elderly people. Senile plaques, a pathologic hallmark of AD, are composed of amyloid β peptide (Aβ). Aβ aggregation produces toxic oligomers and fibrils, causing neuronal dysfunction and memory loss. Aβ is generated from two sequential proteolytic cleavages of a membrane protein, amyloid precursor protein (APP), by β- and γ-secretases. The transmembrane (TM) domain of APP, APPTM, is the substrate of γ-secretase for Aβ production. The interaction between APPTM and γ-secretase determines the production of different species of Aβ. Although numerous experimental and theoretical studies of APPTM structure exist, experimental 3D structure of APPTM has not been obtained at atomic resolution. Using the pETM41 vector, we successfully expressed an MBP-APPTM fusion protein. By combining Ni-NTA chromatography, TEV protease cleavage, and reverse phase HPLC (RP-HPLC), we purified isotopically-labeled APPTM for NMR studies. The reconstitution of APPTM into micelles yielded high quality 2D (15)N-(1)H HSQC spectra. This reliable method for APPTM expression and purification lays a good foundation for future structural studies of APPTM using NMR.
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Ball KA, Phillips AH, Nerenberg PS, Fawzi NL, Wemmer DE, Head-Gordon T. Homogeneous and heterogeneous tertiary structure ensembles of amyloid-β peptides. Biochemistry 2011; 50:7612-28. [PMID: 21797254 DOI: 10.1021/bi200732x] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The interplay of modern molecular simulation and high-quality nuclear magnetic resonance (NMR) experiments has reached a fruitful stage for quantitative characterization of structural ensembles of disordered peptides. Amyloid-β 1-42 (Aβ42), the primary peptide associated with Alzheimer's disease, and fragments such as Aβ21-30 are both classified as intrinsically disordered peptides (IDPs). We use a variety of NMR observables to validate de novo molecular dynamics simulations in explicit water to characterize the tertiary structure ensemble of Aβ42 and Aβ21-30 from the perspective of their classification as IDPs. Unlike the Aβ21-30 fragment that conforms to expectations of an IDP that is primarily extended, we find that Aβ42 samples conformations reflecting all possible secondary structure categories and spans the range of IDP classifications from collapsed structured states to highly extended conformations, making it an IDP with a far more heterogeneous tertiary ensemble.
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Affiliation(s)
- K Aurelia Ball
- Graduate Group in Biophysics, University of California, Berkeley, California 94720, United States
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