1
|
Artikis E, Kraus A, Caughey B. Structural biology of ex vivo mammalian prions. J Biol Chem 2022; 298:102181. [PMID: 35752366 PMCID: PMC9293645 DOI: 10.1016/j.jbc.2022.102181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/16/2022] [Accepted: 06/19/2022] [Indexed: 01/13/2023] Open
Abstract
The structures of prion protein (PrP)–based mammalian prions have long been elusive. However, cryo-EM has begun to reveal the near-atomic resolution structures of fully infectious ex vivo mammalian prion fibrils as well as relatively innocuous synthetic PrP amyloids. Comparisons of these various types of PrP fibrils are now providing initial clues to structural features that correlate with pathogenicity. As first indicated by electron paramagnetic resonance and solid-state NMR studies of synthetic amyloids, all sufficiently resolved PrP fibrils of any sort (n > 10) have parallel in-register intermolecular β-stack architectures. Cryo-EM has shown that infectious brain-derived prion fibrils of the rodent-adapted 263K and RML scrapie strains have much larger ordered cores than the synthetic fibrils. These bona fide prion strains share major structural motifs, but the conformational details and the overall shape of the fibril cross sections differ markedly. Such motif variations, as well as differences in sequence within the ordered polypeptide cores, likely contribute to strain-dependent templating. When present, N-linked glycans and glycophosphatidylinositol (GPI) anchors project outward from the fibril surface. For the mouse RML strain, these posttranslational modifications have little effect on the core structure. In the GPI-anchored prion structures, a linear array of GPI anchors along the twisting fibril axis appears likely to bind membranes in vivo, and as such, may account for pathognomonic membrane distortions seen in prion diseases. In this review, we focus on these infectious prion structures and their implications regarding prion replication mechanisms, strains, transmission barriers, and molecular pathogenesis.
Collapse
Affiliation(s)
- Efrosini Artikis
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840 USA
| | - Allison Kraus
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
| | - Byron Caughey
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840 USA.
| |
Collapse
|
2
|
Serpa JJ, Popov KI, Petrotchenko EV, Dokholyan NV, Borchers CH. Structure of prion β-oligomers as determined by short-distance crosslinking constraint-guided discrete molecular dynamics simulations. Proteomics 2021; 21:e2000298. [PMID: 34482645 PMCID: PMC9285417 DOI: 10.1002/pmic.202000298] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 08/10/2021] [Accepted: 08/27/2021] [Indexed: 11/08/2022]
Abstract
The conversion of the native monomeric cellular prion protein (PrPC ) into an aggregated pathological β-oligomeric form (PrPβ ) and an infectious form (PrPSc ) is the central element in the development of prion diseases. The structure of the aggregates and the molecular mechanisms of the conformational changes involved in the conversion are still unknown. We applied mass spectrometry combined with chemical crosslinking, hydrogen/deuterium exchange, limited proteolysis, and surface modification for the differential characterization of the native and the urea+acid-converted prion β-oligomer structures to obtain insights into the mechanisms of conversion and aggregation. For the determination of the structure of the monomer and the dimer unit of the β-oligomer, we applied a recently-developed approach for de novo protein structure determination which is based on the incorporation of zero-length and short-distance crosslinking data as intra- and inter-protein constraints in discrete molecular dynamics simulations (CL-DMD). Based on all of the structural-proteomics experimental data and the computationally predicted structures of the monomer units, we propose the potential mode of assembly of the β-oligomer. The proposed β-oligomer assembly provides a clue on the β-sheet nucleation site, and how template-based conversion of the native prion molecule occurs, growth of the prion aggregates, and maturation into fibrils may occur.
Collapse
Affiliation(s)
- Jason J Serpa
- University of Victoria -Genome British Columbia Proteomics Centre, Victoria, British Columbia, Canada
| | - Konstantin I Popov
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Evgeniy V Petrotchenko
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.,Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Nikolay V Dokholyan
- Department of Pharmacology, Department of Biochemistry & Molecular Biology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Christoph H Borchers
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.,Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow, Russia.,Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| |
Collapse
|
3
|
Kamali-Jamil R, Vázquez-Fernández E, Tancowny B, Rathod V, Amidian S, Wang X, Tang X, Fang A, Senatore A, Hornemann S, Dudas S, Aguzzi A, Young HS, Wille H. The ultrastructure of infectious L-type bovine spongiform encephalopathy prions constrains molecular models. PLoS Pathog 2021; 17:e1009628. [PMID: 34061899 PMCID: PMC8195424 DOI: 10.1371/journal.ppat.1009628] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 06/11/2021] [Accepted: 05/10/2021] [Indexed: 11/18/2022] Open
Abstract
Bovine spongiform encephalopathy (BSE) is a prion disease of cattle that is caused by the misfolding of the cellular prion protein (PrPC) into an infectious conformation (PrPSc). PrPC is a predominantly α-helical membrane protein that misfolds into a β-sheet rich, infectious state, which has a high propensity to self-assemble into amyloid fibrils. Three strains of BSE prions can cause prion disease in cattle, including classical BSE (C-type) and two atypical strains, named L-type and H-type BSE. To date, there is no detailed information available about the structure of any of the infectious BSE prion strains. In this study, we purified L-type BSE prions from transgenic mouse brains and investigated their biochemical and ultrastructural characteristics using electron microscopy, image processing, and immunogold labeling techniques. By using phosphotungstate anions (PTA) to precipitate PrPSc combined with sucrose gradient centrifugation, a high yield of proteinase K-resistant BSE amyloid fibrils was obtained. A morphological examination using electron microscopy, two-dimensional class averages, and three-dimensional reconstructions revealed two structural classes of L-type BSE amyloid fibrils; fibrils that consisted of two protofilaments with a central gap and an average width of 22.5 nm and one-protofilament fibrils that were 10.6 nm wide. The one-protofilament fibrils were found to be more abundant compared to the thicker two-protofilament fibrils. Both fibrillar assemblies were successfully decorated with monoclonal antibodies against N- and C-terminal epitopes of PrP using immunogold-labeling techniques, confirming the presence of polypeptides that span residues 100-110 to 227-237. The fact that the one-protofilament fibrils contain both N- and C-terminal PrP epitopes constrains molecular models for the structure of the infectious conformer in favour of a compact four-rung β-solenoid fold.
Collapse
Affiliation(s)
- Razieh Kamali-Jamil
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Ester Vázquez-Fernández
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Brian Tancowny
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Vineet Rathod
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Sara Amidian
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Xiongyao Wang
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Xinli Tang
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew Fang
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Assunta Senatore
- Institute of Neuropathology, University of Zürich, Zürich, Switzerland
| | - Simone Hornemann
- Institute of Neuropathology, University of Zürich, Zürich, Switzerland
| | - Sandor Dudas
- Canadian BSE Reference Laboratory, Canadian Food Inspection Agency, Lethbridge Laboratory, Lethbridge, Alberta, Canada
| | - Adriano Aguzzi
- Institute of Neuropathology, University of Zürich, Zürich, Switzerland
| | - Howard S. Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Holger Wille
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
4
|
Spagnolli G, Requena JR, Biasini E. Understanding prion structure and conversion. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:19-30. [PMID: 32958233 DOI: 10.1016/bs.pmbts.2020.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Since their original identification, prions have represented enigmatic agents that defy the classical concept of genetic inheritance. For almost four decades, the high-resolution structure of PrPSc, the infectious and misfolded counterpart of the cellular prion protein (PrPC), has remained elusive, mostly due to technical challenges posed by its high insolubility and aggregation propensity. As a result, such a lack of information has critically hampered the search for an effective therapy against prion diseases. Nevertheless, multiple attempts to get insights into the structure of PrPSc have provided important experimental constraints that, despite being at limited resolution, are paving the way for the application of computer-aided technologies to model the three-dimensional architecture of prions and their templated replication mechanism. Here, we review the most relevant studies carried out so far to elucidate the conformation of infectious PrPSc and offer an overview of the most advanced molecular models to explain prion structure and conversion.
Collapse
Affiliation(s)
- Giovanni Spagnolli
- Department of Cellular, Computational and Integrative Biology (CIBIO), Trento, TN, Italy; Dulbecco Telethon Institute, University of Trento, Trento, TN, Italy
| | - Jesús R Requena
- CIMUS Biomedical Research Institute & Department of Medical Sciences, University of Santiago de Compostela-IDIS, Santiago, Spain
| | - Emiliano Biasini
- Department of Cellular, Computational and Integrative Biology (CIBIO), Trento, TN, Italy; Dulbecco Telethon Institute, University of Trento, Trento, TN, Italy.
| |
Collapse
|
5
|
Vanni I, Pirisinu L, Acevedo-Morantes C, Kamali-Jamil R, Rathod V, Di Bari MA, D’Agostino C, Marcon S, Esposito E, Riccardi G, Hornemann S, Senatore A, Aguzzi A, Agrimi U, Wille H, Nonno R. Isolation of infectious, non-fibrillar and oligomeric prions from a genetic prion disease. Brain 2020; 143:1512-1524. [PMID: 32303068 PMCID: PMC7241950 DOI: 10.1093/brain/awaa078] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 01/31/2020] [Accepted: 02/05/2020] [Indexed: 11/21/2022] Open
Abstract
Prions are transmissible agents causing lethal neurodegenerative diseases that are composed of aggregates of misfolded cellular prion protein (PrPSc). Despite non-fibrillar oligomers having been proposed as the most infectious prion particles, prions purified from diseased brains usually consist of large and fibrillar PrPSc aggregates, whose protease-resistant core (PrPres) encompasses the whole C-terminus of PrP. In contrast, PrPSc from Gerstmann-Sträussler-Scheinker disease associated with alanine to valine substitution at position 117 (GSS-A117V) is characterized by a small protease-resistant core, which is devoid of the C-terminus. We thus aimed to investigate the role of this unusual PrPSc in terms of infectivity, strain characteristics, and structural features. We found, by titration in bank voles, that the infectivity of GSS-A117V is extremely high (109.3 ID50 U/g) and is resistant to treatment with proteinase K (109.0 ID50 U/g). We then purified the proteinase K-resistant GSS-A117V prions and determined the amount of infectivity and PrPres in the different fractions, alongside the morphological characteristics of purified PrPres aggregates by electron microscopy. Purified pellet fractions from GSS-A117V contained the expected N- and C-terminally cleaved 7 kDa PrPres, although the yield of PrPres was low. We found that this low yield depended on the low density/small size of GSS-A117V PrPres, as it was mainly retained in the last supernatant fraction. All fractions were highly infectious, thus confirming the infectious nature of the 7 kDa PrPres, with infectivity levels that directly correlated with the PrPres amount detected. Finally, electron microscopy analysis of these fractions showed no presence of amyloid fibrils, but only very small and indistinct, non-fibrillar PrPresparticles were detected and confirmed to contain PrP via immunogold labelling. Our study demonstrates that purified aggregates of 7 kDa PrPres, spanning residues ∼90-150, are highly infectious oligomers that encode the biochemical and biological strain features of the original sample. Overall, the autocatalytic behaviour of the prion oligomers reveals their role in the propagation of neurodegeneration in patients with Gerstmann-Sträussler-Scheinker disease and implies that the C-terminus of PrPSc is dispensable for infectivity and strain features for this prion strain, uncovering the central PrP domain as the minimal molecular component able to encode infectious prions. These findings are consistent with the hypothesis that non-fibrillar prion particles are highly efficient propagators of disease and provide new molecular and morphological constraints on the structure of infectious prions.
Collapse
Affiliation(s)
- Ilaria Vanni
- Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy
| | - Laura Pirisinu
- Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy
| | - Claudia Acevedo-Morantes
- Centre for Prions and Protein Folding Diseases and Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Razieh Kamali-Jamil
- Centre for Prions and Protein Folding Diseases and Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Vineet Rathod
- Centre for Prions and Protein Folding Diseases and Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Michele Angelo Di Bari
- Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy
| | - Claudia D’Agostino
- Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy
| | - Stefano Marcon
- Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy
| | - Elena Esposito
- Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy
| | - Geraldina Riccardi
- Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy
| | - Simone Hornemann
- Institute for Neuropathology, University of Zürich, Zürich, Switzerland
| | - Assunta Senatore
- Institute for Neuropathology, University of Zürich, Zürich, Switzerland
| | - Adriano Aguzzi
- Institute for Neuropathology, University of Zürich, Zürich, Switzerland
| | - Umberto Agrimi
- Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy
| | - Holger Wille
- Centre for Prions and Protein Folding Diseases and Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Romolo Nonno
- Istituto Superiore di Sanità, Department of Food Safety, Nutrition and Veterinary Public Health, Rome, Italy
| |
Collapse
|
6
|
Wilson CJ, Bommarius AS, Champion JA, Chernoff YO, Lynn DG, Paravastu AK, Liang C, Hsieh MC, Heemstra JM. Biomolecular Assemblies: Moving from Observation to Predictive Design. Chem Rev 2018; 118:11519-11574. [PMID: 30281290 PMCID: PMC6650774 DOI: 10.1021/acs.chemrev.8b00038] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Biomolecular assembly is a key driving force in nearly all life processes, providing structure, information storage, and communication within cells and at the whole organism level. These assembly processes rely on precise interactions between functional groups on nucleic acids, proteins, carbohydrates, and small molecules, and can be fine-tuned to span a range of time, length, and complexity scales. Recognizing the power of these motifs, researchers have sought to emulate and engineer biomolecular assemblies in the laboratory, with goals ranging from modulating cellular function to the creation of new polymeric materials. In most cases, engineering efforts are inspired or informed by understanding the structure and properties of naturally occurring assemblies, which has in turn fueled the development of predictive models that enable computational design of novel assemblies. This Review will focus on selected examples of protein assemblies, highlighting the story arc from initial discovery of an assembly, through initial engineering attempts, toward the ultimate goal of predictive design. The aim of this Review is to highlight areas where significant progress has been made, as well as to outline remaining challenges, as solving these challenges will be the key that unlocks the full power of biomolecules for advances in technology and medicine.
Collapse
Affiliation(s)
- Corey J. Wilson
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Andreas S. Bommarius
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Julie A. Champion
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Yury O. Chernoff
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Laboratory of Amyloid Biology & Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg 199034, Russia
| | - David G. Lynn
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Anant K. Paravastu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Chen Liang
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Ming-Chien Hsieh
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Jennifer M. Heemstra
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Requena JR, Wille H. The Structure of the Infectious Prion Protein and Its Propagation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 150:341-359. [PMID: 28838667 DOI: 10.1016/bs.pmbts.2017.06.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The prion diseases, which include Creutzfeldt-Jakob disease in humans, chronic wasting disease in cervids (i.e., deer, elk, moose, and reindeer), bovine spongiform encephalopathy in cattle, as well as sheep and goat scrapie, are caused by the conversion of the cellular prion protein (PrPC) into a disease-causing conformer (PrPSc). PrPC is a regular, GPI-anchored protein that is expressed on the cell surface of neurons and many other cell types. The structure of PrPC is well studied, based on analyses of recombinant PrP, which is thought to mimic the structure of native PrPC. The mature protein contains an N-terminal, unfolded domain and a C-terminal, globular domain that consists of three α-helices and only a small, two-stranded β-sheet. In contrast, PrPSc was found to contain predominantly β-structure and to aggregate into a variety of quaternary structures, such as oligomers, amorphous aggregates, amyloid fibrils, and two-dimensional crystals. The tendency of PrPSc to aggregate into these diverse forms is also responsible for our incomplete knowledge about its molecular structure. Nevertheless, the repeating nature of the more regular PrPSc aggregates has provided informative insights into the structure of the infectious conformer, albeit at limited resolution. These data established a four-rung β-solenoid architecture as the main element of its structure. Moreover, the four-rung β-solenoid architecture provides a molecular framework for an autocatalytic propagation mechanism, which could explain the conversion of PrPC into PrPSc.
Collapse
Affiliation(s)
- Jesús R Requena
- CIMUS Biomedical Research Institute, University of Santiago de Compostela-IDIS, Santiago de Compostela, Spain
| | - Holger Wille
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada.
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
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.
Collapse
|
11
|
Wan W, Wille H, Stöhr J, Kendall A, Bian W, McDonald M, Tiggelaar S, Watts JC, Prusiner SB, Stubbs G. Structural studies of truncated forms of the prion protein PrP. Biophys J 2016; 108:1548-1554. [PMID: 25809267 DOI: 10.1016/j.bpj.2015.01.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/07/2015] [Accepted: 01/13/2015] [Indexed: 11/19/2022] Open
Abstract
Prions are proteins that adopt self-propagating aberrant folds. The self-propagating properties of prions are a direct consequence of their distinct structures, making the understanding of these structures and their biophysical interactions fundamental to understanding prions and their related diseases. The insolubility and inherent disorder of prions have made their structures difficult to study, particularly in the case of the infectious form of the mammalian prion protein PrP. Many investigators have therefore preferred to work with peptide fragments of PrP, suggesting that these peptides might serve as structural and functional models for biologically active prions. We have used x-ray fiber diffraction to compare a series of different-sized fragments of PrP, to determine the structural commonalities among the fragments and the biologically active, self-propagating prions. Although all of the peptides studied adopted amyloid conformations, only the larger fragments demonstrated a degree of structural complexity approaching that of PrP. Even these larger fragments did not adopt the prion structure itself with detailed fidelity, and in some cases their structures were radically different from that of pathogenic PrP(Sc).
Collapse
Affiliation(s)
- William Wan
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Holger Wille
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Jan Stöhr
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Amy Kendall
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Wen Bian
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Michele McDonald
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Sarah Tiggelaar
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Joel C Watts
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Gerald Stubbs
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee.
| |
Collapse
|
12
|
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).
Collapse
|
13
|
Chapron Y, Charlet L, Sahai N. Fate of pathological prion (PrP(sc)92-138) in soil and water: prion-clay nanoparticle molecular dynamics. J Biomol Struct Dyn 2013; 32:1802-16. [PMID: 24152238 DOI: 10.1080/07391102.2013.836461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Pathogenic prion protein scrapie (PrP(sc)) may contaminate soils for decades and remain in water in colloidal suspension, providing infection pathways for animals through the inhalation of ingested dust and soil particles, and drinking water. We used molecular dynamics simulations to understand the strong binding mechanism of this pathogenic peptide with clay mineral surfaces and compared our results to experimental works. We restricted our model to the moiety PrP(92-138), which is a portion of the whole PrP(sc) molecule responsible for infectivity and modeled it using explicit solvating water molecules in contact with a pyrophyllite cleavage plane. Pyrophyllite is taken as a model for common soil clay, but it has no permanent structural charge. However, partial residual negative charges occur on the cleavage plane slab surface due to a slab charge unbalance. The charge is isotropic in 2D and it was balanced with K(+) ions. After partially removing potassium ions, the peptide anchors to the clay surface via up to 10 hydrogen bonds, between protonated lysine or histidine residues and the oxygen atoms of the siloxane cavities. Our results provide insight to the mechanism responsible for the strong association between the PrP(sc) peptide and clay nanoparticles and the associations present in contaminated soil and water which may lead to the infection of animals.
Collapse
Affiliation(s)
- Yves Chapron
- a AIED, Research , 108 rue du puy, La Terrasse , 38660 , France
| | | | | |
Collapse
|
14
|
Zweckstetter M. Conserved amyloid core structure of stop mutants of the human prion protein. Prion 2013; 7:193-7. [PMID: 23406905 DOI: 10.4161/pri.23956] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Prion diseases are associated with misfolding of the natively α-helical prion protein into isoforms that are rich in cross β-structure. However, both the mechanism by which pathological conformations are produced and their structural properties remain unclear. Using a combination of nuclear magnetic resonance spectroscopy, computation, hydroxyl radical probing combined with mass-spectrometry and site-directed mutagenesis, we showed that prion stop mutants that accumulate in amyloidogenic plaque-forming aggregates fold into a β-helix. The polymorphic residue 129 is located in the hydrophobic core of the β-helix in line with a critical role of the 129 region in the packing of protein chains into prion particles. Together with electron microscopy our data support a trimeric left-handed β-helix model in which the trimer interface is formed by residues L125, Y128 and L130. Different prion types or strains might be related to different aggregate structures or filament assemblies.
Collapse
Affiliation(s)
- Markus Zweckstetter
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
| |
Collapse
|
15
|
Skora L, Fonseca-Ornelas L, Hofele RV, Riedel D, Giller K, Watzlawik J, Schulz-Schaeffer WJ, Urlaub H, Becker S, Zweckstetter M. Burial of the polymorphic residue 129 in amyloid fibrils of prion stop mutants. J Biol Chem 2012; 288:2994-3002. [PMID: 23209282 DOI: 10.1074/jbc.m112.423715] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Misfolding of the natively α-helical prion protein into a β-sheet rich isoform is related to various human diseases such as Creutzfeldt-Jakob disease and Gerstmann-Sträussler-Scheinker syndrome. In humans, the disease phenotype is modified by a methionine/valine polymorphism at codon 129 of the prion protein gene. Using a combination of hydrogen/deuterium exchange coupled to NMR spectroscopy, hydroxyl radical probing detected by mass spectrometry, and site-directed mutagenesis, we demonstrate that stop mutants of the human prion protein have a conserved amyloid core. The 129 residue is deeply buried in the amyloid core structure, and its mutation strongly impacts aggregation. Taken together the data support a critical role of the polymorphic residue 129 of the human prion protein in aggregation and disease.
Collapse
Affiliation(s)
- Lukasz Skora
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Skora L, Zweckstetter M. Determination of amyloid core structure using chemical shifts. Protein Sci 2012; 21:1948-53. [PMID: 23033250 DOI: 10.1002/pro.2170] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/24/2012] [Accepted: 09/25/2012] [Indexed: 12/18/2022]
Abstract
Amyloid fibrils are the pathological hallmark of a large variety of neurodegenerative disorders. The structural characterization of amyloid fibrils, however, is challenging due to their non-crystalline, heterogeneous, and often dynamic nature. Thus, the structure of amyloid fibrils of many proteins is still unknown. We here show that the structure calculation program CS-Rosetta can be used to obtain insight into the core structure of amyloid fibrils. Driven by experimental solid-state NMR chemical shifts and taking into account the polymeric nature of fibrils CS-Rosetta allows modeling of the core of amyloid fibrils. Application to the Y145X stop mutant of the human prion protein reveals a left-handed β-helix.
Collapse
Affiliation(s)
- Lukasz Skora
- Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, Göttingen, Germany
| | | |
Collapse
|
17
|
Baron GS, Hughson AG, Raymond GJ, Offerdahl DK, Barton KA, Raymond LD, Dorward DW, Caughey B. Effect of glycans and the glycophosphatidylinositol anchor on strain dependent conformations of scrapie prion protein: improved purifications and infrared spectra. Biochemistry 2011; 50:4479-90. [PMID: 21539311 PMCID: PMC3101284 DOI: 10.1021/bi2003907] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mammalian prion diseases involve conversion of normal prion protein, PrP(C), to a pathological aggregated state (PrP(res)). The three-dimensional structure of PrP(res) is not known, but infrared (IR) spectroscopy has indicated high, strain-dependent β-sheet content. PrP(res) molecules usually contain a glycophosphatidylinositol (GPI) anchor and large Asn-linked glycans, which can also vary with strain. Using IR spectroscopy, we tested the conformational effects of these post-translational modifications by comparing wild-type PrP(res) with GPI- and glycan-deficient PrP(res) produced in GPI-anchorless PrP transgenic mice. These analyses required the development of substantially improved purification protocols. Spectra of both types of PrP(res) revealed conformational differences between the 22L, ME7, and Chandler (RML) murine scrapie strains, most notably in bands attributed to β-sheets. These PrP(res) spectra were also distinct from those of the hamster 263K scrapie strain. Spectra of wild-type and anchorless 22L PrP(res) were nearly indistinguishable. With ME7 PrP(res), modest differences between the wild-type and anchorless spectra were detected, notably an ∼2 cm(-1) shift in an apparent β-sheet band. Collectively, the data provide evidence that the glycans and anchor do not grossly affect the strain-specific secondary structures of PrP(res), at least relative to the differences observed between strains, but can subtly affect turns and certain β-sheet components. Recently reported H-D exchange analyses of anchorless PrP(res) preparations strongly suggested the presence of strain-dependent, solvent-inaccessible β-core structures throughout most of the C-terminal half of PrP(res) molecules, with no remaining α-helix. Our IR data provide evidence that similar core structures also comprise wild-type PrP(res).
Collapse
Affiliation(s)
- Gerald S. Baron
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
| | - Andrew G. Hughson
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
| | - Gregory J. Raymond
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
| | - Danielle K. Offerdahl
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
| | - Kelly A. Barton
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
| | - Lynne D. Raymond
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
| | - David W. Dorward
- Microscopy Unit, Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
| | - Byron Caughey
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
| |
Collapse
|
18
|
Gong B, Ramos A, Vázquez-Fernández E, Silva CJ, Alonso J, Liu Z, Requena JR. Probing structural differences between PrP(C) and PrP(Sc) by surface nitration and acetylation: evidence of conformational change in the C-terminus. Biochemistry 2011; 50:4963-72. [PMID: 21526750 DOI: 10.1021/bi102073j] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We used two chemical modifiers, tetranitromethane (TNM) and acetic anhydride (Ac(2)O), which specifically target accessible tyrosine and lysine residues, respectively, to modify recombinant Syrian hamster PrP(90-231) [rSHaPrP(90-231)] and SHaPrP 27-30, the proteinase K-resistant core of PrP(Sc) isolated from brain of scrapie-infected Syrian hamsters. Our aim was to find locations of conformational change. Modified proteins were subjected to in-gel proteolytic digestion with trypsin or chymotrypsin and subsequent analysis by mass spectrometry (MALDI-TOF). Several differences in chemical reactivity were observed. With TNM, the most conspicuous reactivity difference seen involves peptide E(221)-R(229) (containing Y(225) and Y(226)), which in rSHaPrP(90-231) was much more extensively modified than in SHaPrP 27-30; peptide H(111)-R(136), containing Y(128), was also more modified in rSHaPrP(90-231). Conversely, peptides Y(149)-R(151), Y(157)-R(164), and R(151)-Y(162) suffered more extensive modification in SHaPrP 27-30. Acetic anhydride modified very extensively peptide G(90)-K(106), containing K(101), K(104), K(106), and the amino terminus, in both rSHaPrP(90-231) and SHaPrP 27-30. These results suggest that (1) SHaPrP 27-30 exhibits important conformational differences in the C-terminal region with respect to rSHaPrP(90-231), resulting in the loss of solvent accessibility of Y(225) and Y(226), very solvent-exposed in the latter conformation; because other results suggest preservation of the two C-terminal helices, this might mean that these are tightly packed in SHaPrP 27-30. (2) On the other hand, tyrosines contained in the stretch spanning approximately Y(149)-R(164) are more accessible in SHaPrP 27-30, suggesting rearrangements in α-helix H1 and the short β-sheet of rSHaPrP(90-231). (3) The amino-terminal region of SHaPrP 27-30 is very accessible. These data should help in the validation and construction of structural models of PrP(Sc).
Collapse
Affiliation(s)
- Binbin Gong
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Animal Science and Veterinary Medicine, Jilin University, Changchun, PR China
| | | | | | | | | | | | | |
Collapse
|
19
|
Guest WC, Plotkin SS, Cashman NR. Toward a mechanism of prion misfolding and structural models of PrP(Sc): current knowledge and future directions. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2011; 74:154-160. [PMID: 21218344 DOI: 10.1080/15287394.2011.529065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Despite extensive investigation, many features of prion protein misfolding remain enigmatic. Physicochemical variables known to influence misfolding are reviewed to help elucidate the mechanism of prionogenesis and identify salient features of PrP(Sc), the misfolded conformer of the prion protein. Prospective work on refinement of candidate PrP(Sc) models based on thermodynamic considerations will help to complete atomic-scale structural details missing from experimental studies and may explain the basis for the templating activity of PrP(Sc) in disease.
Collapse
Affiliation(s)
- Will C Guest
- Brain Research Centre, University of British Columbia, Vancouver, BC, Canada
| | | | | |
Collapse
|
20
|
Doak AK, Wille H, Prusiner SB, Shoichet BK. Colloid formation by drugs in simulated intestinal fluid. J Med Chem 2010; 53:4259-65. [PMID: 20426472 PMCID: PMC2874266 DOI: 10.1021/jm100254w] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
![]()
Many organic molecules form colloidal aggregates in aqueous solution at micromolar concentrations. These aggregates promiscuously inhibit soluble proteins and are a major source of false positives in high-throughput screening. Several drugs also form colloidal aggregates, and there has been speculation that this may affect the absorption and distribution of at least one drug in vivo. Here we investigate the ability of drugs to form aggregates in simulated intestinal fluid. Thirty-three Biopharmaceutics Classification System (BCS) class II and class IV drugs, spanning multiple pharmacological activities, were tested for promiscuous aggregation in biochemical buffers. The 22 that behaved as aggregators were then tested for colloid formation in simulated intestinal fluid, a buffer mimicking conditions in the small intestine. Six formed colloids at concentrations equal to or lower than the concentrations reached in the gut, suggesting that aggregation may have an effect on the absorption and distribution of these drugs, and potentially others, in vivo.
Collapse
Affiliation(s)
- Allison K Doak
- Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, California 94158-2550, USA
| | | | | | | |
Collapse
|
21
|
Kumar J, Sreeramulu S, Schmidt TL, Richter C, Vonck J, Heckel A, Glaubitz C, Schwalbe H. Prion Protein Amyloid Formation Involves Structural Rearrangements in the C-Terminal Domain. Chembiochem 2010; 11:1208-13. [DOI: 10.1002/cbic.201000076] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
22
|
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.
Collapse
|
23
|
Li L, Guest W, Huang A, Plotkin SS, Cashman NR. Immunological mimicry of PrPC-PrPSc interactions: antibody-induced PrP misfolding. Protein Eng Des Sel 2009; 22:523-9. [DOI: 10.1093/protein/gzp038] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
24
|
Abstract
The mammalian prion PrPSc causes fatal neurodegenerative ailments in humans and farm animals. The molecular mechanisms of its propagation and transmissibility between species will not be understood until sufficient knowledge of its structure is gathered. This task has been hampered by the insoluble nature of PrPSc, which renders classic techniques, such as nuclear magnetic resonance or x-ray crystallography, unusable. However, a number of alternative approaches, such as limited proteolysis, electron microscopy and Fourier transform infrared spectroscopy, have yielded valuable low-resolution structural information. Pieced together, these data present PrPSc as a stackable molecule whose core is probably a β-solenoid formed by two or three rungs of short β-strands interspersed with numerous loops and turns. A reasonable understanding of its architecture might soon be achieved.
Collapse
Affiliation(s)
- Jesús R Requena
- Prion Research Unit, Department of Medicine, University of Santiago de Compostela, Rua de San Francisco s/n 15782, Santiago de Compostela, Galiza, Spain
| |
Collapse
|
25
|
Surface charge of polyoxometalates modulates polymerization of the scrapie prion protein. Proc Natl Acad Sci U S A 2009; 106:3740-5. [PMID: 19223590 DOI: 10.1073/pnas.0812770106] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Prions are composed solely of an alternatively folded isoform of the prion protein (PrP), designated PrP(Sc). N-terminally truncated PrP(Sc), denoted PrP 27-30, retains infectivity and polymerizes into rods with the ultrastructural and tinctorial properties of amyloid. We report here that some polyoxometalates (POMs) favor polymerization of PrP 27-30 into prion rods, whereas other POMs promote assembly of the protein into 2D crystals. Antibodies reacting with epitopes in denatured PrP 27-30 also bound to 2D crystals treated with 3 M urea. These same antibodies did not bind to either native PrP(Sc) or untreated 2D crystals. By using small, spherical POMs with Keggin-type structures, the central heteroatom was found to determine whether prion rods or 2D crystals were preferentially formed. An example of a Keggin-type POM with a phosphorous heteroatom is the phosphotungstate anion (PTA). Both PTA and a Keggin-type POM with a silicon heteratom have low-charge densities and favor formation of prion rods. In contrast, POMs with boron or hydrogen heteroatoms exhibiting higher negative charges encouraged 2D crystal formation. The 2D crystals of PrP 27-30 produced by selective precipitation with POMs were larger and more well ordered than those obtained by sucrose gradient centrifugation. Our findings argue that the negative charge of Keggin-type POMs determines the quaternary structure adopted by PrP 27-30. The mechanism by which POMs function in competing prion polymerization pathways--one favoring 2D crystals and the other, amyloid fibrils--remains to be established.
Collapse
|
26
|
Godsave SF, Wille H, Kujala P, Latawiec D, DeArmond SJ, Serban A, Prusiner SB, Peters PJ. Cryo-immunogold electron microscopy for prions: toward identification of a conversion site. J Neurosci 2008; 28:12489-99. [PMID: 19020041 PMCID: PMC2796247 DOI: 10.1523/jneurosci.4474-08.2008] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Accepted: 10/05/2008] [Indexed: 11/21/2022] Open
Abstract
Prion diseases are caused by accumulation of an abnormally folded isoform (PrP(Sc)) of the cellular prion protein (PrP(C)). The subcellular distribution of PrP(Sc) and the site of its formation in brain are still unclear. We performed quantitative cryo-immunogold electron microscopy on hippocampal sections from mice infected with the Rocky Mountain Laboratory strain of prions. Two antibodies were used: R2, which recognizes both PrP(C) and PrP(Sc); and F4-31, which only detects PrP(C) in undenatured sections. At a late subclinical stage of prion infection, both PrP(C) and PrP(Sc) were detected principally on neuronal plasma membranes and on vesicles resembling early endocytic or recycling vesicles in the neuropil. The R2 labeling was approximately six times higher in the infected than the uninfected hippocampus and gold clusters were only evident in infected tissue. The biggest increase in labeling density (24-fold) was found on the early/recycling endosome-like vesicles of small-diameter neurites, suggesting these as possible sites of conversion. Trypsin digestion of infected hippocampal sections resulted in a reduction in R2 labeling of >85%, which suggests that a high proportion of PrP(Sc) may be oligomeric, protease-sensitive PrP(Sc).
Collapse
Affiliation(s)
- Susan F. Godsave
- Section of Tumor Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Holger Wille
- Institute for Neurodegenerative Diseases, and
- Departments of Neurology and
| | - Pekka Kujala
- Section of Tumor Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Diane Latawiec
- Institute for Neurodegenerative Diseases, and
- Departments of Neurology and
| | - Stephen J. DeArmond
- Institute for Neurodegenerative Diseases, and
- Departments of Neurology and
- Pathology, University of California, San Francisco, San Francisco, California 94143
| | - Ana Serban
- Institute for Neurodegenerative Diseases, and
| | | | - Peter J. Peters
- Section of Tumor Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| |
Collapse
|
27
|
Frost B, Ollesch J, Wille H, Diamond MI. Conformational diversity of wild-type Tau fibrils specified by templated conformation change. J Biol Chem 2008; 284:3546-51. [PMID: 19010781 DOI: 10.1074/jbc.m805627200] [Citation(s) in RCA: 168] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tauopathies are sporadic and genetic neurodegenerative diseases characterized by aggregation of the microtubule-associated protein Tau. Tau pathology occurs in over 20 phenotypically distinct neurodegenerative diseases, including Alzheimer disease and frontotemporal dementia. The molecular basis of this diversity among sporadic tauopathies is unknown, but distinct fibrillar wild-type (WT) Tau conformations could play a role. Using Fourier transform infrared spectroscopy, circular dichroism, and electron microscopy, we show that WT Tau fibrils and P301L/V337M Tau fibrils have distinct secondary structures, fragilities, and morphologies. Furthermore, P301L/V337M fibrillar seeds induce WT Tau monomer to form a novel fibrillar conformation, termed WT*, that is maintained over multiple seeding reactions. WT* has secondary structure, fragility, and morphology that are similar to P301L/V337M fibrils and distinct from WT fibrils. WT Tau is thus capable of conformational diversity that arises via templated conformation change, as has been described for amyloid beta, beta2-microglobulin, and prion proteins.
Collapse
Affiliation(s)
- Bess Frost
- Department of Neurology, University of California, San Francisco, California 94158, USA
| | | | | | | |
Collapse
|