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Novel quaternary structures of the human prion protein globular domain. Biochimie 2021; 191:118-125. [PMID: 34517052 DOI: 10.1016/j.biochi.2021.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/30/2021] [Accepted: 09/07/2021] [Indexed: 11/22/2022]
Abstract
Prion disease is caused by the misfolding of the cellular prion protein, PrPC, into a self-templating conformer, PrPSc. Nuclear magnetic resonance (NMR) and X-ray crystallography revealed the 3D structure of the globular domain of PrPC and the possibility of its dimerization via an interchain disulfide bridge that forms due to domain swap or by non-covalent association of two monomers. On the contrary, PrPSc is composed by a complex and heterogeneous ensemble of poorly defined conformations and quaternary arrangements that are related to different patterns of neurotoxicity. Targeting PrPC with molecules that stabilize the native conformation of its globular domain emerged as a promising approach to develop anti-prion therapies. One of the advantages of this approach is employing structure-based drug discovery methods to PrPC. Thus, it is essential to expand our structural knowledge about PrPC as much as possible to aid such drug discovery efforts. In this work, we report a crystallographic structure of the globular domain of human PrPC that shows a novel dimeric form and a novel oligomeric arrangement. We use molecular dynamics simulations to explore its structural dynamics and stability and discuss potential implications of these new quaternary structures to the conversion process.
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Cryo-EM structure of an amyloid fibril formed by full-length human prion protein. Nat Struct Mol Biol 2020; 27:598-602. [PMID: 32514176 DOI: 10.1038/s41594-020-0441-5] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/28/2020] [Indexed: 12/31/2022]
Abstract
Prion diseases are caused by the misfolding of prion protein (PrP). Misfolded PrP forms protease-resistant aggregates in vivo (PrPSc) that are able to template the conversion of the native form of the protein (PrPC), a property shared by in vitro-produced PrP fibrils. Here we produced amyloid fibrils in vitro from recombinant, full-length human PrPC (residues 23-231) and determined their structure using cryo-EM, building a model for the fibril core comprising residues 170-229. The PrP fibril consists of two protofibrils intertwined in a left-handed helix. Lys194 and Glu196 from opposing subunits form salt bridges, creating a hydrophilic cavity at the interface of the two protofibrils. By comparison with the structure of PrPC, we propose that two α-helices in the C-terminal domain of PrPC are converted into β-strands stabilized by a disulfide bond in the PrP fibril. Our data suggest that different PrP mutations may play distinct roles in modulating the conformational conversion.
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Glynn C, Sawaya MR, Ge P, Gallagher-Jones M, Short CW, Bowman R, Apostol M, Zhou ZH, Eisenberg DS, Rodriguez JA. Cryo-EM structure of a human prion fibril with a hydrophobic, protease-resistant core. Nat Struct Mol Biol 2020; 27:417-423. [PMID: 32284600 PMCID: PMC7338044 DOI: 10.1038/s41594-020-0403-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 02/28/2020] [Indexed: 01/22/2023]
Abstract
Self-templating assemblies of the human prion protein are clinically associated with transmissible spongiform encephalopathies. Here we present the cryo-EM structure of a denaturant- and protease-resistant fibril formed in vitro spontaneously by a 9.7-kDa unglycosylated fragment of the human prion protein. This human prion fibril contains two protofilaments intertwined with screw symmetry and linked by a tightly packed hydrophobic interface. Each protofilament consists of an extended beta arch formed by residues 106 to 145 of the prion protein, a hydrophobic and highly fibrillogenic disease-associated segment. Such structures of prion polymorphs serve as blueprints on which to evaluate the potential impact of sequence variants on prion disease.
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Affiliation(s)
- Calina Glynn
- Department of Chemistry and Biochemistry; UCLA-DOE Institute for Genomics and Proteomics; STROBE, NSF Science and Technology Center, University of California, Los Angeles, Los Angeles, CA, USA
| | - Michael R Sawaya
- Department of Biological Chemistry and Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics, Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Peng Ge
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Marcus Gallagher-Jones
- Department of Chemistry and Biochemistry; UCLA-DOE Institute for Genomics and Proteomics; STROBE, NSF Science and Technology Center, University of California, Los Angeles, Los Angeles, CA, USA
| | - Connor W Short
- Department of Chemistry and Biochemistry; UCLA-DOE Institute for Genomics and Proteomics; STROBE, NSF Science and Technology Center, University of California, Los Angeles, Los Angeles, CA, USA
| | - Ronquiajah Bowman
- Department of Chemistry and Biochemistry; UCLA-DOE Institute for Genomics and Proteomics; STROBE, NSF Science and Technology Center, University of California, Los Angeles, Los Angeles, CA, USA
| | - Marcin Apostol
- Department of Biological Chemistry and Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics, Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, USA
- ADRx, Thousand Oaks, CA, USA
| | - Z Hong Zhou
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, USA
- Department of Microbiology Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - David S Eisenberg
- Department of Biological Chemistry and Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics, Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Jose A Rodriguez
- Department of Chemistry and Biochemistry; UCLA-DOE Institute for Genomics and Proteomics; STROBE, NSF Science and Technology Center, University of California, Los Angeles, Los Angeles, CA, USA.
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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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5
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Huang JJ, Li XN, Liu WL, Yuan HY, Gao Y, Wang K, Tang B, Pang DW, Chen J, Liang Y. Neutralizing Mutations Significantly Inhibit Amyloid Formation by Human Prion Protein and Decrease Its Cytotoxicity. J Mol Biol 2019; 432:828-844. [PMID: 31821812 DOI: 10.1016/j.jmb.2019.11.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 10/22/2019] [Accepted: 11/26/2019] [Indexed: 12/21/2022]
Abstract
Prion diseases, such as Creutzfeldt-Jakob disease and bovine spongiform encephalopathy, are fatal neurodegenerative diseases that affect many mammals including humans and are caused by the misfolding of prion protein (PrP). A naturally occurring protective polymorphism G127V in human PrP has recently been found to significantly attenuate prion diseases, but the mechanism has remained elusive. We herein report that the hydrophobic chain introduced in G127V significantly inhibits amyloid fibril formation by human PrP, highlighting the protective effect of the G127V polymorphism. We further introduce an amino acid with a different hydrophobic chain (Ile) at the same position and find that G127I has similar protective effects as G127V. Moreover, we show that these two neutralizing mutations, G127V and G127I, significantly decrease the human PrP cytotoxicity resulting from PrP fibril formation, mitochondrial damage, and elevated reactive oxygen species production enhanced by a strong prion-prone peptide PrP 106-126. These findings elucidate the molecular basis for a natural protective polymorphism in PrP and will enable the development of novel therapeutic strategies against prion diseases.
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Affiliation(s)
- Jun-Jie Huang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiang-Ning Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Wan-Li Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Han-Ye Yuan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yuan Gao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Kan Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Bo Tang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Dai-Wen Pang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Jie Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yi Liang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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Iadanza MG, Jackson MP, Hewitt EW, Ranson NA, Radford SE. A new era for understanding amyloid structures and disease. Nat Rev Mol Cell Biol 2019; 19:755-773. [PMID: 30237470 DOI: 10.1038/s41580-018-0060-8] [Citation(s) in RCA: 569] [Impact Index Per Article: 113.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The aggregation of proteins into amyloid fibrils and their deposition into plaques and intracellular inclusions is the hallmark of amyloid disease. The accumulation and deposition of amyloid fibrils, collectively known as amyloidosis, is associated with many pathological conditions that can be associated with ageing, such as Alzheimer disease, Parkinson disease, type II diabetes and dialysis-related amyloidosis. However, elucidation of the atomic structure of amyloid fibrils formed from their intact protein precursors and how fibril formation relates to disease has remained elusive. Recent advances in structural biology techniques, including cryo-electron microscopy and solid-state NMR spectroscopy, have finally broken this impasse. The first near-atomic-resolution structures of amyloid fibrils formed in vitro, seeded from plaque material and analysed directly ex vivo are now available. The results reveal cross-β structures that are far more intricate than anticipated. Here, we describe these structures, highlighting their similarities and differences, and the basis for their toxicity. We discuss how amyloid structure may affect the ability of fibrils to spread to different sites in the cell and between organisms in a prion-like manner, along with their roles in disease. These molecular insights will aid in understanding the development and spread of amyloid diseases and are inspiring new strategies for therapeutic intervention.
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Affiliation(s)
- Matthew G Iadanza
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Matthew P Jackson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Eric W Hewitt
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Neil A Ranson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
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7
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Modulation of Innate Immunity by Amyloidogenic Peptides. Trends Immunol 2019; 40:762-780. [PMID: 31320280 DOI: 10.1016/j.it.2019.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 12/11/2022]
Abstract
Amyloid formation contributes to the development of progressive metabolic and neurodegenerative diseases, while also serving functional roles in host defense. Emerging evidence suggests that as amyloidogenic peptides populate distinct aggregation states, they interact with different combinations of pattern recognition receptors (PRRs) to direct the phenotype and function of tissue-resident and infiltrating innate immune cells. We review recent evidence of innate immunomodulation by distinct forms of amyloidogenic peptides produced by mammals (humans, non-human primates), bacteria, and fungi, as well as the corresponding cell-surface and intracellular PRRs in these interactions, in human and mouse models. Our emerging understanding of peptide aggregate-innate immune cell interactions, and the factors regulating the balance between amyloid function and pathogenicity, might aid the development of anti-amyloid and immunomodulating therapies.
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8
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Terry C, Wadsworth JDF. Recent Advances in Understanding Mammalian Prion Structure: A Mini Review. Front Mol Neurosci 2019; 12:169. [PMID: 31338021 PMCID: PMC6629788 DOI: 10.3389/fnmol.2019.00169] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/17/2019] [Indexed: 12/15/2022] Open
Abstract
Prions are lethal pathogens, which cause fatal neurodegenerative diseases in mammals. They are unique infectious agents and are composed of self-propagating multi-chain assemblies of misfolded host-encoded prion protein (PrP). Understanding prion structure is fundamental to understanding prion disease pathogenesis however to date, the high-resolution structure of authentic ex vivo infectious prions remains unknown. Advances in determining prion structure have been severely impeded by the difficulty in recovering relatively homogeneous prion particles from infected brain and definitively associating infectivity with the PrP assembly state. Recently, however, images of highly infectious ex vivo PrP rods that produce prion-strain specific disease phenotypes in mice have been obtained using cryo-electron microscopy and atomic force microscopy. These images have provided the most detailed description of ex vivo mammalian prions reported to date and have established that prions isolated from multiple strains have a common hierarchical structure. Misfolded PrP is assembled into 20 nm wide rods containing two fibers, each with double helical repeating substructure, separated by a characteristic central gap 8–10 nm in width. Irregularly structured material with adhesive properties distinct to that of the fibers is present within the central gap of the rod. Prions are clearly distinguishable from non-infectious recombinant PrP fibrils generated in vitro and from all other propagating protein structures so far described in other neurodegenerative diseases. The basic architecture of mammalian prions appears to be exceptional and fundamental to their lethal pathogenicity.
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Affiliation(s)
- Cassandra Terry
- Molecular Systems for Health Research Group, School of Human Sciences, London Metropolitan University, London, United Kingdom
| | - Jonathan D F Wadsworth
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, University College London, London, United Kingdom
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9
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Terry C, Harniman RL, Sells J, Wenborn A, Joiner S, Saibil HR, Miles MJ, Collinge J, Wadsworth JDF. Structural features distinguishing infectious ex vivo mammalian prions from non-infectious fibrillar assemblies generated in vitro. Sci Rep 2019; 9:376. [PMID: 30675000 PMCID: PMC6344479 DOI: 10.1038/s41598-018-36700-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/23/2018] [Indexed: 01/19/2023] Open
Abstract
Seeded polymerisation of proteins forming amyloid fibres and their spread in tissues has been implicated in the pathogenesis of multiple neurodegenerative diseases: so called "prion-like" mechanisms. While ex vivo mammalian prions, composed of multichain assemblies of misfolded host-encoded prion protein (PrP), act as lethal infectious agents, PrP amyloid fibrils produced in vitro generally do not. The high-resolution structure of authentic infectious prions and the structural basis of prion strain diversity remain unknown. Here we use cryo-electron microscopy and atomic force microscopy to examine the structure of highly infectious PrP rods isolated from mouse brain in comparison to non-infectious recombinant PrP fibrils generated in vitro. Non-infectious recombinant PrP fibrils are 10 nm wide single fibres, with a double helical repeating substructure displaying small variations in adhesive force interactions across their width. In contrast, infectious PrP rods are 20 nm wide and contain two fibres, each with a double helical repeating substructure, separated by a central gap of 8-10 nm in width. This gap contains an irregularly structured material whose adhesive force properties are strikingly different to that of the fibres, suggestive of a distinct composition. The structure of the infectious PrP rods, which cause lethal neurodegeneration, readily differentiates them from all other protein assemblies so far characterised in other neurodegenerative diseases.
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Affiliation(s)
- Cassandra Terry
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London, W1W 7FF, UK
- London Metropolitan University, North Campus, Holloway Road, London, N7 8DB, UK
| | | | - Jessica Sells
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London, W1W 7FF, UK
- King's Centre for Stem Cells & Regenerative Medicine, King's College London, Guy's Campus, London, SE1 9RT, UK
| | - Adam Wenborn
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London, W1W 7FF, UK
| | - Susan Joiner
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London, W1W 7FF, UK
| | - Helen R Saibil
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, Malet Street, London, WC1E 7HX, UK
| | - Mervyn J Miles
- School of Physics, H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK
| | - John Collinge
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London, W1W 7FF, UK.
| | - Jonathan D F Wadsworth
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London, W1W 7FF, UK.
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Teruya K, Nishizawa K, Oguma A, Sakasegawa Y, Kitamoto T, Doh-Ura K. Intermolecular crosslinking of abnormal prion protein is efficiently induced by a primuline-sensitized photoreaction. Biochim Biophys Acta Gen Subj 2018; 1863:384-394. [PMID: 30447252 DOI: 10.1016/j.bbagen.2018.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/26/2018] [Accepted: 11/13/2018] [Indexed: 11/16/2022]
Abstract
In prion diseases, infectious pathogenic particles that are composed of abnormal prion proteins (PrPSc) accumulate in the brain. PrPSc is biochemically characterized by its protease-resistance core (PrPres), but its structural features have not been fully elucidated. Here, we report that primuline, a fluorescent dye with photosensitization activity, dramatically enhances UV-irradiation-induced SDS-resistant PrPSc/res oligomer formation that can be detected by immunoblot analysis of prion-infected materials. This oligomer formation occurs specifically with PrPSc/res but not with normal prion protein, and it was demonstrated using purified PrPSc/res as well as unpurified materials. The oligomer formation proceeded in both primuline-dose- and UV irradiation time-dependent manners. Treatment with urea or formic acid did not break oligomers into monomers. Neither did the presence of aromatic amino acids modify oligomer formation. Analysis with a panel of anti-prion protein antibodies showed that the antibodies against the N-terminal region of PrPres were less reactive in the dimer than the monomer. These findings suggest that the primuline-sensitized photoreaction enhances intermolecular crosslinking of PrPSc/res molecules at a hydrophobic area of the N-terminal region of PrPres. In the screening of other compounds, photoreactive compounds such as luciferin exhibited a similar but lower activity with respect to oligomer formation than primuline. The enhanced photoreaction with these compounds will be useful for evaluating the structural features of PrPSc/res, especially the interactions between PrPSc/res molecules.
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Affiliation(s)
- Kenta Teruya
- Department of Neurochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Keiko Nishizawa
- Department of Neurochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ayumi Oguma
- Department of Neurochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yuji Sakasegawa
- Department of Neurochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Tetsuyuki Kitamoto
- Department of Neurological Science, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Katsumi Doh-Ura
- Department of Neurochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Abstract
In this review, we detail our current knowledge of PrPSc structure on the basis of structural and computational studies. We discuss the progress toward an atomic resolution description of PrPSc and results from the broader field of amyloid studies that may further inform our knowledge of this structure. Moreover, we summarize work that investigates the role of PrPSc structure in its toxicity, transmissibility, and species specificity. We look forward to an atomic model of PrPSc, which is expected to bring diagnostics and/or therapeutics to the field of prion disease.
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Affiliation(s)
- Jose A Rodriguez
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095
| | - Lin Jiang
- Department of Neurology, Molecular Biology Institute (MBI), and Brain Research Institute (BRI), David Geffen School of Medicine, University of California, Los Angeles, California 90095
| | - David S Eisenberg
- Department of Biological Chemistry, UCLA-DOE Institute for Genomics and Proteomics, Howard Hughes Medical Institute, University of California, Los Angeles, California 90095
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12
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Abstract
Prion diseases are characterized by the deposition of amyloids, misfolded conformers of the prion protein. The misfolded conformation is self-replicating, by a mechanism solely enciphered in the conformation of the protein. Because of low solubility and heterogeneous aggregate sizes, the detailed atomic structure of the infectious isoform is still unknown. Progress has, however, been made, and has allowed insights into the structural and disease-related mechanisms of prions. Many structural models have been proposed, and a number of them support a consensus trimeric β-helical model, significantly more complex than simple amyloid models. There is evidence that such complexity may be a necessary property of prion structure. Knowledge of the structure of prions will provide a greater understanding of the protein isoform conversion mechanism, and could eventually lead to rationally designed intervention strategies.
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Affiliation(s)
- Gerald Stubbs
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 53723
| | - Jan Stöhr
- Institute for Neurodegenerative Diseases, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143
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13
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Collinge J. Mammalian prions and their wider relevance in neurodegenerative diseases. Nature 2016; 539:217-226. [PMID: 27830781 DOI: 10.1038/nature20415] [Citation(s) in RCA: 160] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/09/2016] [Indexed: 02/07/2023]
Abstract
Prions are notorious protein-only infectious agents that cause invariably fatal brain diseases following silent incubation periods that can span a lifetime. These diseases can arise spontaneously, through infection or be inherited. Remarkably, prions are composed of self-propagating assemblies of a misfolded cellular protein that encode information, generate neurotoxicity and evolve and adapt in vivo. Although parallels have been drawn with Alzheimer's disease and other neurodegenerative conditions involving the deposition of assemblies of misfolded proteins in the brain, insights are now being provided into the usefulness and limitations of prion analogies and their aetiological and therapeutic relevance.
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Affiliation(s)
- John Collinge
- Medical Research Council Prion Unit, University College London Institute of Neurology, London WC1N 3BG, UK.,Department of Neurodegenerative Disease, University College London Institute of Neurology, London WC1N 3BG, UK
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The Structure of Mammalian Prions and Their Aggregates. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 329:277-301. [PMID: 28109330 DOI: 10.1016/bs.ircmb.2016.08.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Prion diseases, such as Creutzfeldt-Jakob disease in humans, bovine spongiform encephalopathy in cattle, chronic wasting disease in cervids (i.e., deer, elk, moose, and reindeer), and sheep scrapie, are caused by the misfolding of the cellular prion protein (PrPC) into a disease-causing conformer (PrPSc). PrPC is a normal, GPI-anchored protein that is expressed on the surface of neurons and other cell types. The structure of PrPC is well understood, based on studies of recombinant PrP, which closely mimics the structure of native PrPC. In contrast, PrPSc is prone to aggregate into a variety of quaternary structures, such as oligomers, amorphous aggregates, and amyloid fibrils. The propensity of PrPSc to assemble into these diverse forms of aggregates is also responsible for our limited knowledge about its structure. Then again, the repeating nature of certain regular PrPSc aggregates has allowed (lower resolution) insights into the structure of the infectious conformer, establishing a four-rung β-solenoid structure as a key element of its architecture.
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15
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The Structural Architecture of an Infectious Mammalian Prion Using Electron Cryomicroscopy. PLoS Pathog 2016; 12:e1005835. [PMID: 27606840 PMCID: PMC5015997 DOI: 10.1371/journal.ppat.1005835] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 08/01/2016] [Indexed: 12/31/2022] Open
Abstract
The structure of the infectious prion protein (PrPSc), which is responsible for Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy, has escaped all attempts at elucidation due to its insolubility and propensity to aggregate. PrPSc replicates by converting the non-infectious, cellular prion protein (PrPC) into the misfolded, infectious conformer through an unknown mechanism. PrPSc and its N-terminally truncated variant, PrP 27–30, aggregate into amorphous aggregates, 2D crystals, and amyloid fibrils. The structure of these infectious conformers is essential to understanding prion replication and the development of structure-based therapeutic interventions. Here we used the repetitive organization inherent to GPI-anchorless PrP 27–30 amyloid fibrils to analyze their structure via electron cryomicroscopy. Fourier-transform analyses of averaged fibril segments indicate a repeating unit of 19.1 Å. 3D reconstructions of these fibrils revealed two distinct protofilaments, and, together with a molecular volume of 18,990 Å3, predicted the height of each PrP 27–30 molecule as ~17.7 Å. Together, the data indicate a four-rung β-solenoid structure as a key feature for the architecture of infectious mammalian prions. Furthermore, they allow to formulate a molecular mechanism for the replication of prions. Knowledge of the prion structure will provide important insights into the self-propagation mechanisms of protein misfolding. The structure of the infectious prion (PrPSc), which is responsible for Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy, has escaped all attempts at elucidation due to its propensity to aggregate. Here, we use the repetitive organization inherent in amyloid fibrils to analyze the structure of GPI-anchorless PrP 27–30 via electron cryomicroscopy. Fourier-transform analysis of averaged fibril segments indicates a repeating unit of 19.1 Å. In agreement with this observation, 3D reconstructions reveal that each fibril contains two distinct protofilaments and that the height of each PrP 27–30 molecule in these fibrils is ~17.7 Å. Together the data indicate a four-rung β-solenoid structure as a key feature for the architecture of infectious mammalian prions. The data conflict with all previous models for the structure of PrPSc and allow the formulation of a molecular mechanism for the replication of prions.
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16
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Terry C, Wenborn A, Gros N, Sells J, Joiner S, Hosszu LLP, Tattum MH, Panico S, Clare DK, Collinge J, Saibil HR, Wadsworth JDF. Ex vivo mammalian prions are formed of paired double helical prion protein fibrils. Open Biol 2016; 6:rsob.160035. [PMID: 27249641 PMCID: PMC4892434 DOI: 10.1098/rsob.160035] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 04/13/2016] [Indexed: 12/20/2022] Open
Abstract
Mammalian prions are hypothesized to be fibrillar or amyloid forms of prion protein (PrP), but structures observed to date have not been definitively correlated with infectivity and the three-dimensional structure of infectious prions has remained obscure. Recently, we developed novel methods to obtain exceptionally pure preparations of prions from mouse brain and showed that pathogenic PrP in these high-titre preparations is assembled into rod-like assemblies. Here, we have used precise cell culture-based prion infectivity assays to define the physical relationship between the PrP rods and prion infectivity and have used electron tomography to define their architecture. We show that infectious PrP rods isolated from multiple prion strains have a common hierarchical assembly comprising twisted pairs of short fibres with repeating substructure. The architecture of the PrP rods provides a new structural basis for understanding prion infectivity and can explain the inability to systematically generate high-titre synthetic prions from recombinant PrP.
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Affiliation(s)
- Cassandra Terry
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Adam Wenborn
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Nathalie Gros
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Jessica Sells
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Susan Joiner
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Laszlo L P Hosszu
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - M Howard Tattum
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Silvia Panico
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK
| | - Daniel K Clare
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK
| | - John Collinge
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Helen R Saibil
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK
| | - Jonathan D F Wadsworth
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
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17
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Wenborn A, Terry C, Gros N, Joiner S, D'Castro L, Panico S, Sells J, Cronier S, Linehan JM, Brandner S, Saibil HR, Collinge J, Wadsworth JDF. A novel and rapid method for obtaining high titre intact prion strains from mammalian brain. Sci Rep 2015; 5:10062. [PMID: 25950908 PMCID: PMC4423448 DOI: 10.1038/srep10062] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/26/2015] [Indexed: 02/02/2023] Open
Abstract
Mammalian prions exist as multiple strains which produce characteristic and highly reproducible phenotypes in defined hosts. How this strain diversity is encoded by a protein-only agent remains one of the most interesting and challenging questions in biology with wide relevance to understanding other diseases involving the aggregation or polymerisation of misfolded host proteins. Progress in understanding mammalian prion strains has however been severely limited by the complexity and variability of the methods used for their isolation from infected tissue and no high resolution structures have yet been reported. Using high-throughput cell-based prion bioassay to re-examine prion purification from first principles we now report the isolation of prion strains to exceptional levels of purity from small quantities of infected brain and demonstrate faithful retention of biological and biochemical strain properties. The method's effectiveness and simplicity should facilitate its wide application and expedite structural studies of prions.
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Affiliation(s)
- Adam Wenborn
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Cassandra Terry
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Nathalie Gros
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Susan Joiner
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Laura D'Castro
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Silvia Panico
- Department of Crystallography and Institute of Structural and Molecular Biology, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK
| | - Jessica Sells
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Sabrina Cronier
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Jacqueline M Linehan
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Sebastian Brandner
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Helen R Saibil
- Department of Crystallography and Institute of Structural and Molecular Biology, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK
| | - John Collinge
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Jonathan D F Wadsworth
- MRC Prion Unit and Department of Neurodegenerative Disease, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
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18
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Requena JR, Wille H. The structure of the infectious prion protein: experimental data and molecular models. Prion 2015; 8:60-6. [PMID: 24583975 PMCID: PMC7030906 DOI: 10.4161/pri.28368] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The structures of the infectious prion protein, PrP(Sc), and that of its proteolytically truncated variant, PrP 27-30, have evaded experimental determination due to their insolubility and propensity to aggregate. Molecular modeling has been used to fill this void and to predict their structures, but various modeling approaches have produced significantly different models. The disagreement between the different modeling solutions indicates the limitations of this method. Over the years, in absence of a three-dimensional (3D) structure, a variety of experimental techniques have been used to gain insights into the structure of this biologically, medically, and agriculturally important isoform. Here, we present an overview of experimental results that were published in recent years, and which provided new insights into the molecular architecture of PrP(Sc) and PrP 27-30. Furthermore, we evaluate all published models in light of these recent, experimental data, and come to the conclusion that none of the models can accommodate all of the experimental constraints. Moreover, this conclusion constitutes an open invitation for renewed efforts to model the structure of PrP(Sc).
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19
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Acevedo-Morantes CY, Wille H. The structure of human prions: from biology to structural models-considerations and pitfalls. Viruses 2014; 6:3875-92. [PMID: 25333467 PMCID: PMC4213568 DOI: 10.3390/v6103875] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 12/27/2022] Open
Abstract
Prion diseases are a family of transmissible, progressive, and uniformly fatal neurodegenerative disorders that affect humans and animals. Although cross-species transmissions of prions are usually limited by an apparent “species barrier”, the spread ofa prion disease to humans by ingestion of contaminated food, or via other routes of exposure, indicates that animal prions can pose a significant public health risk. The infectious agent responsible for the transmission of prion diseases is a misfolded conformer of the prion protein, PrPSc, a pathogenic isoform of the host-encoded, cellular prion protein,PrPC. The detailed mechanisms of prion conversion and replication, as well as the high-resolution structure of PrPSc, are unknown. This review will discuss the general background related to prion biology and assess the structural models proposed to date,while highlighting the experimental challenges of elucidating the structure of PrPSc.
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Affiliation(s)
- Claudia Y Acevedo-Morantes
- Department of Biochemistry and Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada.
| | - Holger Wille
- Department of Biochemistry and Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada.
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20
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Klimova N, Makarava N, Baskakov IV. The diversity and relationship of prion protein self-replicating states. Virus Res 2014; 207:113-9. [PMID: 25312451 DOI: 10.1016/j.virusres.2014.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/15/2014] [Accepted: 10/01/2014] [Indexed: 10/24/2022]
Abstract
It has become evident that the prion protein (PrP) can form a diverse range of self-replicating structures in addition to bona fide PrP(Sc) or strain-specific PrP(Sc) variants. Some self-replicating states can be only produced in vitro, whereas others can be formed in vivo and in vitro. While transmissible, not all states that replicate in vivo are truly pathogenic. Some of them can replicate silently without causing symptoms or clinical diseases. In the current article we discuss the data on PK-digestion patterns of different self-replicating PrP states in connection with other structural data available to date and assess possible relationships between different self-replicating states. Even though different self-replicating PrP states appear to have significantly different global folding patterns, it seems that the C-terminal region exhibits a cross-β-sheet structure in all self-replicating states, as this region acquires the proteolytically most stable conformation. We also discuss the possibility of the transformation of self-replicating states and triggering of PrP(Sc) formation within the frame of the deformed templating model. The spread of silent self-replicating states is of a particular concern because they can lead to transmissible prion disease. Moreover, examples on how different replication requirements favor different states are discussed. This knowledge can help in designing conditions for selective amplification of a particular PrP state in vitro.
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Affiliation(s)
- Nina Klimova
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, 725 W. Lombard St., Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 725 W. Lombard St., Baltimore, MD 21201, USA
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, 725 W. Lombard St., Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 725 W. Lombard St., Baltimore, MD 21201, USA
| | - Ilia V Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, 725 W. Lombard St., Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 725 W. Lombard St., Baltimore, MD 21201, USA.
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21
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Roucou X. Regulation of PrP(C) signaling and processing by dimerization. Front Cell Dev Biol 2014; 2:57. [PMID: 25364762 PMCID: PMC4207009 DOI: 10.3389/fcell.2014.00057] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 09/19/2014] [Indexed: 12/15/2022] Open
Abstract
The cellular prion protein (PrPC) is a glycosylphosphatidylinositol (GPI)-anchored protein present at the cell surface. PrPC N-terminal moiety is intrinsically disordered and is able to interact with a variety of ligands. Physiological ligands have neurotrophic activity, whilst others, including protein toxic oligomers, have neurotoxic functions. These two opposite activities involve different interacting partners and result from different PrPC-activated signaling pathways. Remarkably, PrPC may be inactivated either by physiological endoproteolysis and release of the N-terminal domain, or by ectodomain shedding. Ligand-induced PrPC dimerization or enforced dimerization of PrPC indicate that PrPC dimerization represents an important molecular switch for both intracellular signaling and inactivation by the release of PrPC N-terminal domain or shedding. In this review, we summarize evidence that cell surface receptor activity of PrPC is finely regulated by dimerization.
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Affiliation(s)
- Xavier Roucou
- Department of Biochemistry, Faculty of Medicine, Université de Sherbrooke Sherbrooke, QC, Canada
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22
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Trevitt CR, Hosszu LLP, Batchelor M, Panico S, Terry C, Nicoll AJ, Risse E, Taylor WA, Sandberg MK, Al-Doujaily H, Linehan JM, Saibil HR, Scott DJ, Collinge J, Waltho JP, Clarke AR. N-terminal domain of prion protein directs its oligomeric association. J Biol Chem 2014; 289:25497-508. [PMID: 25074940 PMCID: PMC4162156 DOI: 10.1074/jbc.m114.566588] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The self-association of prion protein (PrP) is a critical step in the pathology of prion diseases. It is increasingly recognized that small non-fibrillar β-sheet-rich oligomers of PrP may be of crucial importance in the prion disease process. Here, we characterize the structure of a well defined β-sheet-rich oligomer, containing ∼12 PrP molecules, and often enclosing a central cavity, formed using full-length recombinant PrP. The N-terminal region of prion protein (residues 23-90) is required for the formation of this distinct oligomer; a truncated form comprising residues 91-231 forms a broad distribution of aggregated species. No infectivity or toxicity was found using cell and animal model systems. This study demonstrates that examination of the full repertoire of conformers and assembly states that can be accessed by PrP under specific experimental conditions should ideally be done using the full-length protein.
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Affiliation(s)
- Clare R Trevitt
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Laszlo L P Hosszu
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Mark Batchelor
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Silvia Panico
- the Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX
| | - Cassandra Terry
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Andrew J Nicoll
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Emmanuel Risse
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - William A Taylor
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Malin K Sandberg
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Huda Al-Doujaily
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Jacqueline M Linehan
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Helen R Saibil
- the Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX
| | - David J Scott
- the National Centre for Macromolecular Hydrodynamics, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, the ISIS Spallation Neutron and Muon Source and Research Complex at Harwell, Rutherford Appleton Laboratory, Oxfordshire, OX11 0FA, and
| | - John Collinge
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG
| | - Jonathan P Waltho
- the Department of Molecular Biology and Biotechnology, Krebs Institute for Biomolecular Research, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Anthony R Clarke
- From the Department of Neurodegenerative Disease, MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG,
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23
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v Berlepsch H, Ludwig K, Schade B, Haag R, Böttcher C. Progress in the direct structural characterization of fibrous amphiphilic supramolecular assemblies in solution by transmission electron microscopic techniques. Adv Colloid Interface Sci 2014; 208:279-92. [PMID: 24508499 DOI: 10.1016/j.cis.2014.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/09/2014] [Accepted: 01/11/2014] [Indexed: 11/28/2022]
Abstract
The self-assembly of amphiphilic molecules into fibrous structures has been the subject of numerous studies over past decades due to various current and promising technical applications. Although very different in their head group chemistry many natural as well as synthetic amphiphilic compounds derived from carbohydrates, carbocyanine dyes, or amino acids tend to form fibrous structures by molecular self-assembly in water predominantly twisted ribbons or tubes. Often a transition between these assembly structures is observed, which is a phenomenon already theoretically approached by Wolfgang Helfrich and still focus point in current research. With the development of suitable sample preparation and electron optical imaging techniques, cryogenic transmission electron microscopy (cryo-TEM) in combination with three-dimensional (3D) reconstruction techniques has become a particular popular direct characterization technique for supramolecular assemblies in general. Here we review the recent progress in deriving precise structural information from cryo-TEM data of particularly fibrous structures preferably in three dimensions.
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Affiliation(s)
- Hans v Berlepsch
- Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany; Core Facility BioSupraMol an der Freien Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany
| | - Kai Ludwig
- Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany
| | - Boris Schade
- Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany
| | - Rainer Haag
- Core Facility BioSupraMol an der Freien Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany; Institut für Chemie und Biochemie - Organische Chemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany
| | - Christoph Böttcher
- Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany.
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24
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Shirai T, Saito M, Kobayashi A, Asano M, Hizume M, Ikeda S, Teruya K, Morita M, Kitamoto T. Evaluating prion models based on comprehensive mutation data of mouse PrP. Structure 2014; 22:560-71. [PMID: 24560805 DOI: 10.1016/j.str.2013.12.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 12/21/2013] [Accepted: 12/28/2013] [Indexed: 10/25/2022]
Abstract
The structural details of the essential entity of prion disease, fibril prion protein (PrP(Sc)), are still elusive despite the large body of evidence supporting the prion hypothesis. Five major working models of PrP(Sc) structure, which are not compatible with each other, have been proposed. However, no systematic evaluation has been performed on those models. We devised a method that combined systematic point mutation with threading on knowledge-based amino acid potentials. A comprehensive mutation experiment was performed on mouse prion protein, and the PrP(Sc) conversion efficiency of each mutant was examined. The models were evaluated based on the mutation data by using the threading method. Although the data turned out to be rather more consistent with the models that assumed a conversion of the N-terminal region of core PrP into a β helix than with others, substantial modifications were also required to further improve the current model based on recent experimental results.
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Affiliation(s)
- Tsuyoshi Shirai
- Department of Computer Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan; Bioinformatics Research Division, Japan Science and Technology Agency, 5-3, Yonbancho, Chiyoda-ku, Tokyo 102-8666 Japan.
| | - Mihoko Saito
- Department of Computer Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan; Bioinformatics Research Division, Japan Science and Technology Agency, 5-3, Yonbancho, Chiyoda-ku, Tokyo 102-8666 Japan
| | - Atsushi Kobayashi
- Department of Neurological Science, Tohoku University Graduate School of Medicine Research, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Masahiro Asano
- Department of Neurological Science, Tohoku University Graduate School of Medicine Research, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Masaki Hizume
- Department of Neurological Science, Tohoku University Graduate School of Medicine Research, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Shino Ikeda
- Department of Neurological Science, Tohoku University Graduate School of Medicine Research, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Kenta Teruya
- Department of Neurological Science, Tohoku University Graduate School of Medicine Research, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Masanori Morita
- Department of Neurological Science, Tohoku University Graduate School of Medicine Research, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan; Research and Development Division, Benesis Corporation, Kitahama, Chuo-Ku, Osaka 541-850, Japan
| | - Tetsuyuki Kitamoto
- Department of Neurological Science, Tohoku University Graduate School of Medicine Research, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
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25
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Singh JP, Whitford PC, Hayre NR, Onuchic J, Cox DL. Massive conformation change in the prion protein: Using dual-basin structure-based models to find misfolding pathways. Proteins 2012; 80:1299-307. [PMID: 22274922 DOI: 10.1002/prot.24026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 10/19/2011] [Accepted: 11/18/2011] [Indexed: 11/11/2022]
Abstract
We employ all-atom structure-based models with a force field with multiple energetic basins for the C-terminal (residues 166-226) of the mammalian prion protein. One basin represents the known alpha-helical (αH) structure while the other represents the same residues in a left-handed beta-helical (LHBH) conformation. The LHBH structure has been proposed to help describe one class of in vitro grown fibrils, as well as possibly self-templating the conversion of normal cellular prion protein to the infectious form. Yet, it is unclear how the protein may make this global rearrangement. Our results demonstrate that the conformation changes are not strongly limited by large-scale geometry modification and that there may exist an overall preference for the LHBH conformation. Furthermore, our model presents novel intermediate trapping conformations with twisted LHBH structure.
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Affiliation(s)
- Jesse P Singh
- Department of Physics and the Institute for Complex Adaptive Matter, University of California at Davis, Davis, California 95616, USA.
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26
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Hafner-Bratkovič I, Jerala R. Disulfide mapping reveals the domain swapping as the crucial process of the structural conversion of prion protein. Prion 2011; 5:56-9. [PMID: 21555920 DOI: 10.4161/pri.5.2.16232] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Prion diseases are infectious conformational diseases. Despite the determination of many native prion protein (PrP) structures and in vitro production of infectious prions from recombinant PrP the structural background of PrP conversion remains the largest unsolved problem. The aggregated state of PrP (Sc) makes it inaccessible to high resolution techniques, therefore indirect methods have to be used to investigate the conversion process. We engineered disulfide bridges into the structured domain of PrP in order to determine the secondary structure elements that remain conserved upon conversion. Rather surprisingly, introduction of disulfides into each or both of the subdomains B1-H1-B2 and H2-H3 of the C-terminal globular domain retained the robust ability to convert into fibrils with increased content of β-structure, indistinguishable from the wild-type PrP. On the other hand disulfide bridges tethering the two subdomains completely prevented conversion, while their reduction reversed their conversion ability. The same conversion propensity was replicated also in prion infected cell lines. Experiments with combinations of engineered cysteine residues further support that domain swapping, centered on the B2-H2 loop, previously associated to species barrier, leads to PrP swapped dimers as the building block of prion fibrils.
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Affiliation(s)
- Iva Hafner-Bratkovič
- Department of Biotechnology, National Institute of Chemistry, Ljubljana, Slovenia
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Hafner-Bratkovic I, Bester R, Pristovsek P, Gaedtke L, Veranic P, Gaspersic J, Mancek-Keber M, Avbelj M, Polymenidou M, Julius C, Aguzzi A, Vorberg I, Jerala R. Globular domain of the prion protein needs to be unlocked by domain swapping to support prion protein conversion. J Biol Chem 2011; 286:12149-56. [PMID: 21324909 DOI: 10.1074/jbc.m110.213926] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Prion diseases are fatal transmissible neurodegenerative diseases affecting many mammalian species. The normal prion protein (PrP) converts into a pathological aggregated form, PrPSc, which is enriched in the β-sheet structure. Although the high resolution structure of the normal PrP was determined, the structure of the converted form of PrP remains inaccessible to high resolution techniques. To map the PrP conversion process we introduced disulfide bridges into different positions within the globular domain of PrP, tethering selected secondary structure elements. The majority of tethered PrP mutants exhibited increased thermodynamic stability, nevertheless, they converted efficiently. Only the disulfides that tether subdomain B1-H1-B2 to subdomain H2-H3 prevented PrP conversion in vitro and in prion-infected cell cultures. Reduction of disulfides recovered the ability of these mutants to convert, demonstrating that the separation of subdomains is an essential step in conversion. Formation of disulfide-linked proteinase K-resistant dimers in fibrils composed of a pair of single cysteine mutants supports the model based on domain-swapped dimers as the building blocks of prion fibrils. In contrast to previously proposed structural models of PrPSc suggesting conversion of large secondary structural segments, we provide evidence for the conservation of secondary structural elements of the globular domain upon PrP conversion. Previous studies already showed that dimerization is the rate-limiting step in PrP conversion. We show that separation and swapping of subdomains of the globular domain is necessary for conversion. Therefore, we propose that the domain-swapped dimer of PrP precedes amyloid formation and represents a potential target for therapeutic intervention.
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Affiliation(s)
- Iva Hafner-Bratkovic
- Department of Biotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
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Structural dependence of HET-s amyloid fibril infectivity assessed by cryoelectron microscopy. Proc Natl Acad Sci U S A 2011; 108:3252-7. [PMID: 21300906 DOI: 10.1073/pnas.1011342108] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
HET-s is a prion protein of the fungus Podospora anserina which, in the prion state, is active in a self/nonself recognition process called heterokaryon incompatibility. Its prionogenic properties reside in the C-terminal "prion domain." The HET-s prion domain polymerizes in vitro into amyloid fibrils whose properties depend on the pH of assembly; above pH 3, infectious singlet fibrils are produced, and below pH 3, noninfectious triplet fibrils. To investigate the correlation between structure and infectivity, we performed cryo-EM analyses. Singlet fibrils have a helical pitch of approximately 410 Å and a left-handed twist. Triplet fibrils have three protofibrils whose lateral dimensions (36 × 25 Å) and axial packing (one subunit per 9.4 Å) match those of singlets but differ in their supercoiling. At 8.5-Å resolution, the cross-section of the singlet fibril reconstruction is largely consistent with that of a β-solenoid model previously determined by solid-state NMR. Reconstructions of the triplet fibrils show three protofibrils coiling around a common axis and packed less tightly at pH 3 than at pH 2, eventually peeling off. Taken together with the earlier observation that fragmentation of triplet fibrils by sonication does not increase infectivity, these observations suggest a novel mechanism for self-propagation, whereby daughter fibrils nucleate on the lateral surface of singlet fibrils. In triplets, this surface is occluded, blocking nucleation and thereby explaining their lack of infectivity.
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Comparison of Alzheimer Abeta(1-40) and Abeta(1-42) amyloid fibrils reveals similar protofilament structures. Proc Natl Acad Sci U S A 2009; 106:19813-8. [PMID: 19843697 DOI: 10.1073/pnas.0905007106] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We performed mass-per-length (MPL) measurements and electron cryomicroscopy (cryo-EM) with 3D reconstruction on an Abeta(1-42) amyloid fibril morphology formed under physiological pH conditions. The data show that the examined Abeta(1-42) fibril morphology has only one protofilament, although two protofilaments were observed with a previously studied Abeta(1-40) fibril. The latter fibril was resolved at 8 A resolution showing pairs of beta-sheets at the cores of the two protofilaments making up a fibril. Detailed comparison of the Abeta(1-42) and Abeta(1-40) fibril structures reveals that they share an axial twofold symmetry and a similar protofilament structure. Furthermore, the MPL data indicate that the protofilaments of the examined Abeta(1-40) and Abeta(1-42) fibrils have the same number of Abeta molecules per cross-beta repeat. Based on this data and the previously studied Abeta(1-40) fibril structure, we describe a model for the arrangement of peptides within the Abeta(1-42) fibril.
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30
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Abstract
A conformational isoform of the mammalian prion protein (PrP(Sc)) is the sole component of the infectious pathogen that causes the prion diseases. We have obtained X-ray fiber diffraction patterns from infectious prions that show cross-beta diffraction: meridional intensity at 4.8 A resolution, indicating the presence of beta strands running approximately at right angles to the filament axis and characteristic of amyloid structure. Some of the patterns also indicated the presence of a repeating unit along the fiber axis, corresponding to four beta-strands. We found that recombinant (rec) PrP amyloid differs substantially from highly infectious brain-derived prions, both in structure as demonstrated by the diffraction data, and in heterogeneity as shown by electron microscopy. In addition to the strong 4.8 A meridional reflection, the recPrP amyloid diffraction is characterized by strong equatorial intensity at approximately 10.5 A, absent from brain-derived prions, and indicating the presence of stacked beta-sheets. Synthetic prions recovered from transgenic mice inoculated with recPrP amyloid displayed structural characteristics and homogeneity similar to those of naturally occurring prions. The relationship between the structural differences and prion infectivity is uncertain, but might be explained by any of several hypotheses: only a minority of recPrP amyloid possesses a replication-competent conformation, the majority of recPrP amyloid has to undergo a conformational maturation to acquire replication competency, or inhibitory forms of recPrP amyloid interfere with replication during the initial transmission.
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31
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Hosszu LLP, Trevitt CR, Jones S, Batchelor M, Scott DJ, Jackson GS, Collinge J, Waltho JP, Clarke AR. Conformational properties of beta-PrP. J Biol Chem 2009; 284:21981-21990. [PMID: 19369250 PMCID: PMC2755922 DOI: 10.1074/jbc.m809173200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 03/19/2009] [Indexed: 11/06/2022] Open
Abstract
Prion propagation involves a conformational transition of the cellular form of prion protein (PrPC) to a disease-specific isomer (PrPSc), shifting from a predominantly alpha-helical conformation to one dominated by beta-sheet structure. This conformational transition is of critical importance in understanding the molecular basis for prion disease. Here, we elucidate the conformational properties of a disulfide-reduced fragment of human PrP spanning residues 91-231 under acidic conditions, using a combination of heteronuclear NMR, analytical ultracentrifugation, and circular dichroism. We find that this form of the protein, which similarly to PrPSc, is a potent inhibitor of the 26 S proteasome, assembles into soluble oligomers that have significant beta-sheet content. The monomeric precursor to these oligomers exhibits many of the characteristics of a molten globule intermediate with some helical character in regions that form helices I and III in the PrPC conformation, whereas helix II exhibits little evidence for adopting a helical conformation, suggesting that this region is a likely source of interaction within the initial phases of the transformation to a beta-rich conformation. This precursor state is almost as compact as the folded PrPC structure and, as it assembles, only residues 126-227 are immobilized within the oligomeric structure, leaving the remainder in a mobile, random-coil state.
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Affiliation(s)
- Laszlo L. P. Hosszu
- From the MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG
- the Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, and
| | - Clare R. Trevitt
- From the MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG
| | - Samantha Jones
- From the MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG
| | - Mark Batchelor
- From the MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG
| | - David J. Scott
- the National Centre for Macromolecular Hydrodynamics, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, United Kingdom
| | - Graham S. Jackson
- From the MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG
| | - John Collinge
- From the MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG
| | - Jonathan P. Waltho
- the Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, and
| | - Anthony R. Clarke
- From the MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG
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32
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White HE, Hodgkinson JL, Jahn TR, Cohen-Krausz S, Gosal WS, Müller S, Orlova EV, Radford SE, Saibil HR. Globular tetramers of beta(2)-microglobulin assemble into elaborate amyloid fibrils. J Mol Biol 2009; 389:48-57. [PMID: 19345691 PMCID: PMC2726924 DOI: 10.1016/j.jmb.2009.03.066] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 03/27/2009] [Accepted: 03/30/2009] [Indexed: 11/24/2022]
Abstract
Amyloid fibrils are ordered polymers in which constituent polypeptides adopt a non-native fold. Despite their importance in degenerative human diseases, the overall structure of amyloid fibrils remains unknown. High-resolution studies of model peptide assemblies have identified residues forming cross-β-strands and have revealed some details of local β-strand packing. However, little is known about the assembly contacts that define the fibril architecture. Here we present a set of three-dimensional structures of amyloid fibrils formed from full-length β2-microglobulin, a 99-residue protein involved in clinical amyloidosis. Our cryo-electron microscopy maps reveal a hierarchical fibril structure built from tetrameric units of globular density, with at least three different subunit interfaces in this homopolymeric assembly. These findings suggest a more complex superstructure for amyloid than hitherto suspected and prompt a re-evaluation of the defining features of the amyloid fold.
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Affiliation(s)
- Helen E White
- Department of Crystallography and Institute of Structural and Molecular Biology, Birkbeck College, London, UK
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33
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Skerget K, Vilfan A, Pompe-Novak M, Turk V, Waltho JP, Turk D, Zerovnik E. The mechanism of amyloid-fibril formation by stefin B: temperature and protein concentration dependence of the rates. Proteins 2009; 74:425-36. [PMID: 18636508 DOI: 10.1002/prot.22156] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cystatins, a family of structurally related cysteine proteinase inhibitors, have proved to be useful model system to study amyloidogenesis. We have extended previous studies of the kinetics of amyloid-fibril formation by human stefin B (cystatin B) and some of its mutants, and proposed an improved model for the reaction. Overall, the observed kinetics follow the nucleation and growth behavior observed for many other amyloidogenic proteins. The minimal kinetic scheme that best fits measurements of changes in CD and thioflavin T fluorescence as a function of protein concentration and temperature includes nucleation (modeled as N(I) irreversible transitions with equivalent rates (k(I)), which fitted with N(I) = 64), fibril growth and nonproductive oligomerization, best explained by an off-pathway state with a rate-limiting escape rate. Three energies of activation were derived from global fitting to the minimal kinetic scheme, and independently through the fitting of the individual component rates. Nucleation was found to be a first-order process within an oligomeric species with an enthalpy of activation of 55 +/- 4 kcal mol(-1). Fibril growth was a second-order process with an enthalpy of activation (27 +/- 5 kcal mol(-1)), which is indistinguishable from that of tetramer formation by cystatins, which involves limited conformational changes including proline trans to cis isomerization. The highest enthalpy of activation (95 +/- 5 kcal mol(-1) at 35 degrees C), characteristic of a substantial degree of unfolding as observed prior to domain-swapping reactions, equated with the escape rate of the off-pathway oligomeric state.
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Affiliation(s)
- Katja Skerget
- Department of Biochemistry, Molecular and Structural Biology, JoZef Stefan Institute, 1000 Ljubljana, Slovenia
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Moore RA, Taubner LM, Priola SA. Prion protein misfolding and disease. Curr Opin Struct Biol 2009; 19:14-22. [PMID: 19157856 DOI: 10.1016/j.sbi.2008.12.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Revised: 12/02/2008] [Accepted: 12/04/2008] [Indexed: 12/21/2022]
Abstract
Transmissible spongiform encephalopathies (TSEs or prion diseases) are a rare group of invariably fatal neurodegenerative disorders that affect humans and other mammals. TSEs are protein misfolding diseases that involve the accumulation of an abnormally aggregated form of the normal host prion protein (PrP). They are unique among protein misfolding disorders in that they are transmissible and have different strains of infectious agents that are associated with unique phenotypes in vivo. A wealth of biological and biophysical evidence now suggests that the molecular basis for prion diseases may be encoded by protein conformation. The purpose of this review is to provide an overview of the existing structural information for PrP within the context of what is known about the biology of prion disease.
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Affiliation(s)
- Roger A Moore
- Rocky Mountain Laboratories, Laboratory of Persistent Viral Diseases, NIAID, NIH, 903 S. 4th Street, Hamilton, MT 59840, United States.
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35
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Periole X, Rampioni A, Vendruscolo M, Mark AE. Factors That Affect the Degree of Twist in β-Sheet Structures: A Molecular Dynamics Simulation Study of a Cross-β Filament of the GNNQQNY Peptide. J Phys Chem B 2009; 113:1728-37. [DOI: 10.1021/jp8078259] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xavier Periole
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Department of Biophysical Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom, and School of Molecular and Microbiological Sciences and the Institute of Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Aldo Rampioni
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Department of Biophysical Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom, and School of Molecular and Microbiological Sciences and the Institute of Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Michele Vendruscolo
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Department of Biophysical Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom, and School of Molecular and Microbiological Sciences and the Institute of Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Alan E. Mark
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Department of Biophysical Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom, and School of Molecular and Microbiological Sciences and the Institute of Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia
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Abstract
According to the amyloid pore hypothesis, pores formed by small oligomers of misfolded amyloidogenic proteins cause membrane leakage with the unregulated rapid influx of ions leading to cell death. Ultrastructurally, pores reconstituted in vitro have mainly been characterised so far, and the presence of in situ pores in the amyloid tissues has not yet been demonstrated. In this study, the presence of in situbeta amyloid (Abeta) pores was shown with high resolution transmission electron microscopy, in the neuronal cell membrane as well as in the membrane of mitochondria-like organelles in the brain with Alzheimer's disease. They are 16 nm wide and 11 nm long flat columnar structures made up of a single cylindrical layer (wall) of laterally associated Abeta protofilaments which surrounds a 10 nm wide opening or lumen. Protofilaments are the basic unit of the fibrils of all amyloid-forming proteins and peptides. Individual extracellular Abeta protofilaments were 2-3 nm wide straight tubular structures with helical wall formed by the tight coiling of 1 nm wide Abeta filaments. These in situ Abeta pores are similar but not identical to in vitro reconstituted Abeta pores.
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Affiliation(s)
- Sadayuki Inoue
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.
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37
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Jain S, Udgaonkar JB. Evidence for Stepwise Formation of Amyloid Fibrils by the Mouse Prion Protein. J Mol Biol 2008; 382:1228-41. [DOI: 10.1016/j.jmb.2008.07.052] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 06/28/2008] [Accepted: 07/21/2008] [Indexed: 11/16/2022]
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38
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Scrapie prion protein structural constraints obtained by limited proteolysis and mass spectrometry. J Mol Biol 2008; 382:88-98. [PMID: 18621059 DOI: 10.1016/j.jmb.2008.06.070] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 05/16/2008] [Accepted: 06/24/2008] [Indexed: 01/30/2023]
Abstract
Elucidation of the structure of scrapie prion protein (PrP(Sc)), essential to understand the molecular mechanism of prion transmission, continues to be one of the major challenges in prion research and is hampered by the insolubility and polymeric character of PrP(Sc). Limited proteolysis is a useful tool to obtain insight on structural features of proteins: proteolytic enzymes cleave proteins more readily at exposed sites, preferentially within loops, and rarely in beta-strands. We treated PrP(Sc) isolated from brains of hamsters infected with 263K and drowsy prions with varying concentrations of proteinase K (PK). After PK deactivation, PrP(Sc) was denatured, reduced, and cleaved at Cys179 with 2-nitro-5-thiocyanatobenzoic acid. Fragments were analyzed by nano-HPLC/mass spectrometry and matrix-assisted laser desorption/ionization. Besides the known cleavages at positions 90, 86, and 92 for 263K prions and at positions 86, 90, 92, 98, and 101 for drowsy prions, our data clearly demonstrate the existence of additional cleavage sites at more internal positions, including 117, 119, 135, 139, 142, and 154 in both strains. PK concentration dependence analysis and limited proteolysis after partial unfolding of PrP(Sc) confirmed that only the mentioned cleavage sites at the N-terminal side of the PrP(Sc) are susceptible to PK. Our results indicate that besides the "classic" amino-terminal PK cleavage points, PrP(Sc) contains, in its middle core, regions that show some degree of susceptibility to proteases and must therefore correspond to subdomains with some degree of structural flexibility, interspersed with stretches of amino acids of high resistance to proteases. These results are compatible with a structure consisting of short beta-sheet stretches connected by loops and turns.
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Kunes KC, Clark SC, Cox DL, Singh RRP. Left handed beta helix models for mammalian prion fibrils. Prion 2008; 2:81-90. [PMID: 19098440 PMCID: PMC2634523 DOI: 10.4161/pri.2.2.7059] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Accepted: 09/23/2008] [Indexed: 12/11/2022] Open
Abstract
We propose models for in vitro grown mammalian prion protein fibrils based upon left handed beta helices formed both from the N-terminal and C-terminal regions of the proteinase resistant infectious prion core. The C-terminal threading onto a beta-helical structure is almost uniquely determined by fixing the cysteine disulfide bond on a helix corner. In comparison to known left handed helical peptides, the resulting model structures have similar stability attributes including relatively low root mean square deviations in all atom molecular dynamics, substantial side-chain-to-side-chain hydrogen bonding, good volume packing fraction, and low hydrophilic/hydrophobic frustration. For the N-terminus, we propose a new threading of slightly more than two turns, which improves upon the above characteristics relative to existing three turn beta-helical models. The N-terminal and C-terminal beta helices can be assembled into eight candidate models for the fibril repeat units, held together by large hinge (order 30 residues) domain swapping, with three amenable to fibril promoting domain swapping via a small (five residue) hinge on the N-terminal side. Small concentrations of the metastable C-terminal beta helix in vivo might play a significant role in templating the infectious conformation and in enhancing conversion kinetics for inherited forms of the disease and explain resistance (for canines) involving hypothesized coupling to the methionine 129 sulfur known to play a role in human disease.
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Affiliation(s)
- Kay C Kunes
- Department of Physics, University of California, Davis, California 95616, USA
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40
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Sanghera N, Wall M, Vénien-Bryan C, Pinheiro TJT. Globular and pre-fibrillar prion aggregates are toxic to neuronal cells and perturb their electrophysiology. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:873-81. [PMID: 18374666 DOI: 10.1016/j.bbapap.2008.02.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 02/15/2008] [Accepted: 02/20/2008] [Indexed: 11/26/2022]
Abstract
Prion diseases are characterised at autopsy by neuronal loss and accumulation of amorphous protein aggregates and/or amyloid fibrils in the brains of humans and animals. These protein deposits result from the conversion of the cellular, mainly alpha-helical prion protein (PrP(C)) to the beta-sheet-rich isoform (PrP(Sc)). Although the pathogenic mechanism of prion diseases is not fully understood, it appears that protein aggregation is itself neurotoxic and not the product of cell death. The precise nature of the neurotoxic species and mechanism of cell death are yet to be determined, although recent studies with other amyloidogenic proteins suggest that ordered pre-fibrillar or oligomeric forms may be responsible for cellular dysfunction. In this study we have refolded recombinant prion protein (rPrP) to two distinct forms rich in beta-sheet structure with an intact disulphide bond. Here we report on the structural properties of globular aggregates and pre-fibrils of rPrP and show that both states are toxic to neuronal cells in culture. We show that exogenous rPrP aggregates are internalised by neuronal cells and found in the cytoplasm. We also measured the changes in electrophysiological properties of cultured neuronal cells on exposure to exogenous prion aggregates and discuss the implications of these findings.
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Affiliation(s)
- Narinder Sanghera
- Department of Biological Sciences, Gibbet Hill Road, University of Warwick, Coventry CV4 7AL, UK
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41
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De Simone A, Pedone C, Vitagliano L. Structure, dynamics, and stability of assemblies of the human prion fragment SNQNNF. Biochem Biophys Res Commun 2008; 366:800-6. [DOI: 10.1016/j.bbrc.2007.12.047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 12/04/2007] [Indexed: 11/28/2022]
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Abstract
Protein misfolding and the subsequent assembly of protein molecules into aggregates of various morphologies represent common mechanisms that link a number of important human diseases, known as protein-misfolding diseases. The current list of these disorders includes (but is not limited to) numerous neurodegenerative diseases, cataracts, arthritis, medullary carcinoma of the thyroid, late-onset diabetes mellitus, symptomatic (hemodialysis-related) beta(2)-microglobulin amyloidosis, arthritis and many other systemic, localized and familial amyloidoses. Progress in understanding protein-misfolding pathologies and in potential rational drug design aimed at the inhibition or reversal of protein aggregation depends on our ability to study the details of the misfolding process, to follow the aggregation process and to see and analyze the structure and mechanical properties of the aggregated particles. Nanoimaging provides a method to monitor the aggregation process, visualize protein aggregates and analyze their properties and provides fundamental knowledge of key factors that lead to protein misfolding and self-assembly in various protein-misfolding pathologies, therefore advancing medicine dramatically.
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Affiliation(s)
- Vladimir N Uversky
- Indiana University School of Medicine, Center for Computational Biology and Bioinformatics, Department of Biochemistry and Molecular Biology, IN, USA.
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43
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Molecular architecture of human prion protein amyloid: a parallel, in-register beta-structure. Proc Natl Acad Sci U S A 2007; 104:18946-51. [PMID: 18025469 DOI: 10.1073/pnas.0706522104] [Citation(s) in RCA: 272] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transmissible spongiform encephalopathies (TSEs) represent a group of fatal neurodegenerative diseases that are associated with conformational conversion of the normally monomeric and alpha-helical prion protein, PrP(C), to the beta-sheet-rich PrP(Sc). This latter conformer is believed to constitute the main component of the infectious TSE agent. In contrast to high-resolution data for the PrP(C) monomer, structures of the pathogenic PrP(Sc) or synthetic PrP(Sc)-like aggregates remain elusive. Here we have used site-directed spin labeling and EPR spectroscopy to probe the molecular architecture of the recombinant PrP amyloid, a misfolded form recently reported to induce transmissible disease in mice overexpressing an N-terminally truncated form of PrP(C). Our data show that, in contrast to earlier, largely theoretical models, the con formational conversion of PrP(C) involves major refolding of the C-terminal alpha-helical region. The core of the amyloid maps to C-terminal residues from approximately 160-220, and these residues form single-molecule layers that stack on top of one another with parallel, in-register alignment of beta-strands. This structural insight has important implications for understanding the molecular basis of prion propagation, as well as hereditary prion diseases, most of which are associated with point mutations in the region found to undergo a refolding to beta-structure.
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Hafner-Bratkovic I, Gaspersic J, Smid LM, Bresjanac M, Jerala R. Curcumin binds to the alpha-helical intermediate and to the amyloid form of prion protein - a new mechanism for the inhibition of PrP(Sc) accumulation. J Neurochem 2007; 104:1553-64. [PMID: 17996023 DOI: 10.1111/j.1471-4159.2007.05105.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Conversion of the native, predominantly alpha-helical conformation of prion protein (PrP) into the beta-stranded conformation is characteristic for the transmissible spongiform encephalopathies such as Creutzfeld-Jakob disease. Curcumin, an extended planar molecule and a dietary polyphenol, inhibits in vitro conversion of PrP and formation of protease resistant PrP in neuroblastoma cell lines. Curcumin recognizes the converted beta-form of the PrP both as oligomers and fibrils but not the native form. Curcumin binds to the prion fibrils in the left-handed chiral arrangement as determined by circular dichroism. We show that curcumin labels the plaques of the brain sections of variant Creutzfeld-Jakob disease cases and stains the same structures as antibodies against the PrP. In contrast to thioflavin T, curcumin also binds to the alpha-helical intermediate of PrP present at acidic pH at stoichiometry of 1 : 1. Congo red competes with curcumin for binding to the alpha-intermediate as well as to the beta-form of PrP but is toxic and binds also to the native form of PrP. We therefore show that the partially unfolded structural intermediate of the PrP can be targeted by non-toxic compound of natural origin.
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Affiliation(s)
- Iva Hafner-Bratkovic
- Department of Biotechnology, National Institute of Chemistry, School of Medicine, University of Ljubljana, Slovenia
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Jahn TR, Radford SE. Folding versus aggregation: polypeptide conformations on competing pathways. Arch Biochem Biophys 2007; 469:100-17. [PMID: 17588526 PMCID: PMC2706318 DOI: 10.1016/j.abb.2007.05.015] [Citation(s) in RCA: 297] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 05/16/2007] [Accepted: 05/21/2007] [Indexed: 12/19/2022]
Abstract
Protein aggregation has now become recognised as an important and generic aspect of protein energy landscapes. Since the discovery that numerous human diseases are caused by protein aggregation, the biophysical characterisation of misfolded states and their aggregation mechanisms has received increased attention. Utilising experimental techniques and computational approaches established for the analysis of protein folding reactions has ensured rapid advances in the study of pathways leading to amyloid fibrils and amyloid-related aggregates. Here we describe recent experimental and theoretical advances in the elucidation of the conformational properties of dynamic, heterogeneous and/or insoluble protein ensembles populated on complex, multidimensional protein energy landscapes. We discuss current understanding of aggregation mechanisms in this context and describe how the synergy between biochemical, biophysical and cell-biological experiments are beginning to provide detailed insights into the partitioning of non-native species between protein folding and aggregation pathways.
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Lennon CW, Cox HD, Hennelly SP, Chelmo SJ, McGuirl MA. Probing structural differences in prion protein isoforms by tyrosine nitration. Biochemistry 2007; 46:4850-60. [PMID: 17397138 PMCID: PMC2562509 DOI: 10.1021/bi0617254] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two conformational isomers of recombinant hamster prion protein (residues 90-232) have been probed by reaction with two tyrosine nitration reagents, peroxynitrite and tetranitromethane. Two conserved tyrosine residues (tyrosines 149 and 150) are not labeled by either reagent in the normal cellular form of the prion protein. These residues become reactive after the protein has been converted to the beta-oligomeric isoform, which is used as a model of the fibrillar form that causes disease. After conversion, a decrease in reactivity is noted for two other conserved residues, tyrosine 225 and tyrosine 226, whereas little to no effect was observed for other tyrosines. Thus, tyrosine nitration has identified two specific regions of the normal prion protein isoform that undergo a change in chemical environment upon conversion to a structure that is enriched in beta-sheet.
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Affiliation(s)
- Christopher W. Lennon
- Division of Biological Sciences and the Biomolecular Structure and Dynamics Program, The University of Montana, Missoula, MT 59812 USA
| | | | - Scott P. Hennelly
- Division of Biological Sciences and the Biomolecular Structure and Dynamics Program, The University of Montana, Missoula, MT 59812 USA
| | | | - Michele A. McGuirl
- Division of Biological Sciences and the Biomolecular Structure and Dynamics Program, The University of Montana, Missoula, MT 59812 USA
- Corresponding author information: Michele A. McGuirl, Clapp Building 204, Division of Biological Sciences, 32 Campus Drive The University of Montana, Missoula, MT 59812, , (406) 243-4404 phone, (406) 243-4304 fax
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Ranson N, Stromer T, Bousset L, Melki R, Serpell LC. Insights into the architecture of the Ure2p yeast protein assemblies from helical twisted fibrils. Protein Sci 2006; 15:2481-7. [PMID: 17001037 PMCID: PMC2242408 DOI: 10.1110/ps.062215206] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The protein Ure2 from baker's yeast is associated with a heritable and transmissible phenotypic change in the yeast Saccharomyces cerevisiae. Such prion properties are thought to arise from the fact that Ure2p is able to self-assemble into insoluble fibrils. Assemblies of Ure2p are composed of full-length proteins in which the structure of the globular, functional, C-terminal domain is retained. We have carried out structural studies on full-length, wild-type Ure2p fibrils with a regularly twisted morphology. Using electron microscopy and cryo-electron microscopy with image analysis we show high-resolution images of the twisted filaments revealing details within the fibrillar structure. We examine these details in light of recent proposed models and discuss how this new information contributes to an understanding of the architecture of Ure2p yeast prion fibrils.
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Affiliation(s)
- Neil Ranson
- Astbury Centre for Structural Molecular Biology and Institute for Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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Tahiri-Alaoui A, Sim VL, Caughey B, James W. Molecular heterosis of prion protein beta-oligomers. A potential mechanism of human resistance to disease. J Biol Chem 2006; 281:34171-8. [PMID: 16980300 DOI: 10.1074/jbc.m606606200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The gene encoding prion protein is polymorphic in human populations, with over 40% of native Europeans, for example, being heterozygous for the Met-129 and Val-129 alleles. The polymorphism affects both the incidence and the clinical presentation of a range of prion diseases, with heterozygotes generally showing the highest levels of resistance. It has been suggested that an earlier epidemic of prion diseases exerted balancing selection on the two alleles, and we have previously demonstrated that the two encoded proteins have potentially compensating tendencies to form amyloid and soluble beta-oligomers, respectively, in vitro. More strikingly, here we demonstrate that mixed oligomers, composed of both allelic forms, show an extreme sluggishness in converting to amyloid in comparison with oligomers homogenous for either allele. It may be that this example of molecular heterosis in vitro provides the basis for maintenance of the polymorphism in the population and that beta-oligomers represent a form of PrP sequestered from pathogenic amyloid formation in vivo.
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Affiliation(s)
- Abdessamad Tahiri-Alaoui
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom.
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Sachse C, Xu C, Wieligmann K, Diekmann S, Grigorieff N, Fändrich M. Quaternary Structure of a Mature Amyloid Fibril from Alzheimer’s Aβ(1-40) Peptide. J Mol Biol 2006; 362:347-54. [PMID: 16920151 DOI: 10.1016/j.jmb.2006.07.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Revised: 06/08/2006] [Accepted: 07/05/2006] [Indexed: 11/26/2022]
Abstract
Amyloid fibrils are fibrous polypeptide aggregates that can be formed in vitro and under pathologic conditions, such as in type II diabetes, Alzheimer's and Creutzfeldt-Jakob diseases. Using a range of biophysical techniques including electron microscopy we have analysed the quaternary structure of a mature amyloid fibril formed from the Abeta(1-40) peptide from Alzheimer's disease. We find that the analysed fibril is discernibly polar and represents a left-handed helix consisting of two or three protofilaments. These are organised in a manner so that the cross-section is, under the present resolution conditions (2.6 nm), S-shaped. In the cross-section, each protofilament can accommodate two beta-strands, suggesting that each protofilament contains two cross-beta-sheets. These data shed new light on the way in which Abeta(1-40) and the protofilaments formed from this peptide are organised within the mature fibril.
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Affiliation(s)
- Carsten Sachse
- Leibniz Institut für Altersforschung, Fritz-Lipmann Institut, 07745 Jena, Germany
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