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Scialò C, De Cecco E, Manganotti P, Legname G. Prion and Prion-Like Protein Strains: Deciphering the Molecular Basis of Heterogeneity in Neurodegeneration. Viruses 2019; 11:E261. [PMID: 30875755 PMCID: PMC6466326 DOI: 10.3390/v11030261] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/08/2019] [Accepted: 03/10/2019] [Indexed: 12/12/2022] Open
Abstract
Increasing evidence suggests that neurodegenerative disorders share a common pathogenic feature: the presence of deposits of misfolded proteins with altered physicochemical properties in the Central Nervous System. Despite a lack of infectivity, experimental data show that the replication and propagation of neurodegenerative disease-related proteins including amyloid-β (Aβ), tau, α-synuclein and the transactive response DNA-binding protein of 43 kDa (TDP-43) share a similar pathological mechanism with prions. These observations have led to the terminology of "prion-like" to distinguish between conditions with noninfectious characteristics but similarities with the prion replication and propagation process. Prions are considered to adapt their conformation to changes in the context of the environment of replication. This process is known as either prion selection or adaptation, where a distinct conformer present in the initial prion population with higher propensity to propagate in the new environment is able to prevail over the others during the replication process. In the last years, many studies have shown that prion-like proteins share not only the prion replication paradigm but also the specific ability to aggregate in different conformations, i.e., strains, with relevant clinical, diagnostic and therapeutic implications. This review focuses on the molecular basis of the strain phenomenon in prion and prion-like proteins.
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Affiliation(s)
- Carlo Scialò
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy.
| | - Elena De Cecco
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy.
| | - Paolo Manganotti
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, University Hospital and Health Services of Trieste, University of Trieste, 34149 Trieste, Italy.
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy.
- ELETTRA Sincrotrone Trieste S.C.p.A, Basovizza, 34149 Trieste, Italy.
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2
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Yamaguchi KI, Kuwata K. Formation and properties of amyloid fibrils of prion protein. Biophys Rev 2018; 10:517-525. [PMID: 29204880 PMCID: PMC5899736 DOI: 10.1007/s12551-017-0377-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/23/2017] [Indexed: 02/06/2023] Open
Abstract
Amyloid fibrils formed from prion protein (PrP) are associated with prion diseases. In this review we discuss a number of extrinsic and intrinsic experimental factors related to the formation of PrP amyloid fibrils in vitro. We first examined the effects of ultrasonic power on the induction of amyloid fibrillation from PrP. The most important conclusion drawn from the results is that an applied ultrasonic power of approximately 2 W enhanced the nucleation of amyloid fibrils efficiently but that more powerful ultrasonication led to retardation of growth. We also reviewed evidence on the amyloidogenic regions of PrP based on peptide screening throughout the polypeptide sequence. These results showed that helix 2 (H2) peptides of PrP were capable of both the fibrillation and propagation of straight, long fibrils. Moreover, the conformation of preformed H2 fibrils changed reversibly depending on the pH of the solution, implying that interactions between side-chains modulated the conformation of amyloid fibrils. The evidence discussed in this review relates specifically to PrP but may be relevant to other amyloidogenic proteins.
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Affiliation(s)
- Kei-ichi Yamaguchi
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 Japan
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido 1-1, Gifu, 501-1193 Japan
| | - Kazuo Kuwata
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido 1-1, Gifu, 501-1193 Japan
- Graduate School of Medicine, Gifu University, Yanagido 1-1, Gifu, 501-1193 Japan
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3
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Sandberg A, Nyström S. Purification and Fibrillation of Recombinant Human Amyloid-β, Prion Protein, and Tau Under Native Conditions. Methods Mol Biol 2018; 1779:147-166. [PMID: 29886532 DOI: 10.1007/978-1-4939-7816-8_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Protein misfolding, aggregation, and amyloid formation is involved in a large number of diseases. Recombinantly expressed proteins to study the amyloid fibril formation process are important for mechanistic studies. We here report protocols for production, purification, and fibrillation of three different proteins commonly found in cerebral amyloid; Aβ and Tau found in Alzheimer's disease, Chronic traumatic brain injury, Corticobasal degeneration, and Progressive Supranuclear Palsy and human prion protein found in Creutzfeldt-Jakob's disease. The three protocols have in common that the protein is in a pH-neutral phosphate saline buffer during fibrillation to mimic their endogenous near physiological environment.
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Affiliation(s)
- Alexander Sandberg
- Chemistry, IFM-Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Sofie Nyström
- Chemistry, IFM-Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.
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4
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Legname G, Moda F. The Prion Concept and Synthetic Prions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 150:147-156. [PMID: 28838659 DOI: 10.1016/bs.pmbts.2017.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Abstract
Transmissible spongiform encephalopathies or prion diseases are a group of fatal neurodegenerative diseases caused by unconventional infectious agents, known as prions (PrPSc). Prions derive from a conformational conversion of the normally folded prion protein (PrPC), which acquires pathological and infectious features. Moreover, PrPSc is able to transmit the pathological conformation to PrPC through a mechanism that is still not well understood. The generation of synthetic prions, which behave like natural prions, is of fundamental importance to study the process of PrPC conversion and to assess the efficacy of therapeutic strategies to interfere with this process. Moreover, the ability of synthetic prions to induce pathology in animals confirms that the pathological properties of the prion strains are all enciphered in abnormal conformations, characterizing these infectious agents.
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Affiliation(s)
- Giuseppe Legname
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
| | - Fabio Moda
- IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy.
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Yu Z, Huang P, Yu Y, Zheng Z, Huang Z, Guo C, Lin D. Unique Properties of the Rabbit Prion Protein Oligomer. PLoS One 2016; 11:e0160874. [PMID: 27529173 PMCID: PMC4987043 DOI: 10.1371/journal.pone.0160874] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 07/26/2016] [Indexed: 11/26/2022] Open
Abstract
Prion diseases, also known as transmissible spongiform encephalopathies (TSEs), are a group of fatal neurodegenerative disorders infecting both humans and animals. Recent works have demonstrated that the soluble prion protein oligomer (PrPO), the intermediate of the conformational transformation from the host-derived cellular form (PrPC) to the disease-associated Scrapie form (PrPSc), exerts the major neurotoxicity in vitro and in vivo. Rabbits show strong resistance to TSEs, the underlying mechanism is unclear to date. It is expected that the relative TSEs-resistance of rabbits is closely associated with the unique properties of rabbit prion protein oligomer which remain to be addressed in detail. In the present work, we prepared rabbit prion protein oligomer (recRaPrPO) and human prion protein oligomer (recHuPrPO) under varied conditions, analyzed the effects of pH, NaCl concentration and incubation temperature on the oligomerization, and compared the properties of recRaPrPO and recHuPrPO. We found that several factors facilitated the formation of prion protein oligomers, including low pH, high NaCl concentration, high incubation temperature and low conformational stability of monomeric prion protein. RecRaPrPO was formed more slowly than recHuPrPO at physiological-like conditions (< 57°C, < 150 mM NaCl). Furthermore, recRaPrPO possessed higher susceptibility to proteinase K and lower cytotoxicity in vitro than recHuPrPO. These unique properties of recRaPrPO might substantially contribute to the TSEs-resistance of rabbits. Our work sheds light on the oligomerization of prion proteins and is of benefit to mechanistic understanding of TSEs-resistance of rabbits.
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Affiliation(s)
- Ziyao Yu
- The Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Pei Huang
- The Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yuanhui Yu
- The Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Zhen Zheng
- The Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Zicheng Huang
- The Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Chenyun Guo
- The Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Donghai Lin
- The Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- * E-mail:
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Lin K, Yu Z, Yu Y, Liao X, Huang P, Guo C, Lin D. Distinct effects of Cu2+-binding on oligomerization of human and rabbit prion proteins. Acta Biochim Biophys Sin (Shanghai) 2015; 47:842-50. [PMID: 26350098 DOI: 10.1093/abbs/gmv081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/12/2015] [Indexed: 11/13/2022] Open
Abstract
The cellular prion protein (PrP(C)) is a kind of cell-surface Cu(2+)-binding glycoprotein. The oligomerization of PrP(C) is highly related to transmissible spongiform encephalopathies (TSEs). Cu(2+) plays a vital role in the oligomerization of PrP(C), and participates in the pathogenic process of TSE diseases. It is expected that Cu(2+)-binding has different effects on the oligomerization of TSE-sensitive human PrP(C) (HuPrP(C)) and TSE-resistant rabbit PrP(C) (RaPrP(C)). However, the details of the distinct effects remain unclear. In the present study, we measured the interactions of Cu(2+) with HuPrP(C) (91-230) and RaPrP(C) (91-228) by isothermal titration calorimetry, and compared the effects of Cu(2+)-binding on the oligomerization of both PrPs. The measured dissociation constants (Kd) of Cu(2+) were 11.1 ± 2.1 μM for HuPrP(C) and 21.1 ± 3.1 μM for RaPrP(C). Cu(2+)-binding promoted the oligomerization of HuPrP(C) more significantly than that of RaPrP(C). The far-ultraviolet circular dichroism spectroscopy experiments showed that Cu(2+)-binding induced more significant secondary structure change and increased more β-sheet content for HuPrP(C) compared with RaPrP(C). Moreover, the urea-induced unfolding transition experiments indicated that Cu(2+)-binding decreased the conformational stability of HuPrP(C) more distinctly than that of RaPrP(C). These results suggest that RaPrP(C) possesses a low susceptibility to Cu(2+), potentially weakening the risk of Cu(2+)-induced TSE diseases. Our work sheds light on the Cu(2+)-promoted oligomerization of PrP(C), and may be helpful for further understanding the TSE-resistance of rabbits.
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Affiliation(s)
- Kejiang Lin
- Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 21009, China
| | - Ziyao Yu
- Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 21009, China
| | - Yuanhui Yu
- High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xinli Liao
- High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Pei Huang
- High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Chenyun Guo
- High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Donghai Lin
- Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 21009, China High-field NMR Research Center, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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7
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Flexibility damps macromolecular crowding effects on protein folding dynamics: Application to the murine prion protein (121–231). Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2013.11.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Chatterjee B, Lee CY, Lin C, Chen EHL, Huang CL, Yang CC, Chen RPY. Amyloid core formed of full-length recombinant mouse prion protein involves sequence 127-143 but not sequence 107-126. PLoS One 2013; 8:e67967. [PMID: 23844138 PMCID: PMC3700907 DOI: 10.1371/journal.pone.0067967] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 05/23/2013] [Indexed: 12/23/2022] Open
Abstract
The principal event underlying the development of prion disease is the conversion of soluble cellular prion protein (PrP(C)) into its disease-causing isoform, PrP(Sc). This conversion is associated with a marked change in secondary structure from predominantly α-helical to a high β-sheet content, ultimately leading to the formation of aggregates consisting of ordered fibrillar assemblies referred to as amyloid. In vitro, recombinant prion proteins and short prion peptides from various species have been shown to form amyloid under various conditions and it has been proposed that, theoretically, any protein and peptide could form amyloid under appropriate conditions. To identify the peptide segment involved in the amyloid core formed from recombinant full-length mouse prion protein mPrP(23-230), we carried out seed-induced amyloid formation from recombinant prion protein in the presence of seeds generated from the short prion peptides mPrP(107-143), mPrP(107-126), and mPrP(127-143). Our results showed that the amyloid fibrils formed from mPrP(107-143) and mPrP(127-143), but not those formed from mPrP(107-126), were able to seed the amyloidogenesis of mPrP(23-230), showing that the segment residing in sequence 127-143 was used to form the amyloid core in the fibrillization of mPrP(23-230).
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Affiliation(s)
| | - Chung-Yu Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Chen Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Eric H.-L. Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chao-Li Huang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Chien-Chih Yang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Rita P.-Y. Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
- * E-mail:
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9
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Taguchi Y, Mistica AMA, Kitamoto T, Schätzl HM. Critical significance of the region between Helix 1 and 2 for efficient dominant-negative inhibition by conversion-incompetent prion protein. PLoS Pathog 2013; 9:e1003466. [PMID: 23825952 PMCID: PMC3694865 DOI: 10.1371/journal.ppat.1003466] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 05/13/2013] [Indexed: 01/01/2023] Open
Abstract
Prion diseases are fatal infectious neurodegenerative disorders in man and animals associated with the accumulation of the pathogenic isoform PrPSc of the host-encoded prion protein (PrPc). A profound conformational change of PrPc underlies formation of PrPSc and prion propagation involves conversion of PrPc substrate by direct interaction with PrPSc template. Identifying the interfaces and modalities of inter-molecular interactions of PrPs will highly advance our understanding of prion propagation in particular and of prion-like mechanisms in general. To identify the region critical for inter-molecular interactions of PrP, we exploited here dominant-negative inhibition (DNI) effects of conversion-incompetent, internally-deleted PrP (ΔPrP) on co-expressed conversion-competent PrP. We created a series of ΔPrPs with different lengths of deletions in the region between first and second α-helix (H1∼H2) which was recently postulated to be of importance in prion species barrier and PrP fibril formation. As previously reported, ΔPrPs uniformly exhibited aberrant properties including detergent insolubility, limited protease digestion resistance, high-mannose type N-linked glycans, and intracellular localization. Although formerly controversial, we demonstrate here that ΔPrPs have a GPI anchor attached. Surprisingly, despite very similar biochemical and cell-biological properties, DNI efficiencies of ΔPrPs varied significantly, dependant on location and inversely correlated with the size of deletion. This data demonstrates that H1∼H2 and the region C-terminal to it are critically important for efficient DNI. It also suggests that this region is involved in PrP-PrP interaction and conversion of PrPC into PrPSc. To reconcile the paradox of how an intracellular PrP can exert DNI, we demonstrate that ΔPrPs are subject to both proteasomal and lysosomal/autophagic degradation pathways. Using autophagy pathways ΔPrPs obtain access to the locale of prion conversion and PrPSc recycling and can exert DNI there. This shows that the intracellular trafficking of PrPs is more complex than previously anticipated. Prion diseases are deadly infectious diseases of the brain characterized by accumulation of a pathologic protein (PrPSc) which is derived from the normal prion protein (PrPc). Prions replicate by direct contact in a template-directed refolding process which involves conversion of PrPC into PrPSc. Identifying the modalities of this interaction can advance our molecular understanding of prion diseases. Like substrates and competitive inhibitors of enzymes, a conversion-incompetent PrP can inhibit conversion of normal PrPC, a phenomenon known as dominant-negative inhibition (DNI). Interestingly, some conversion-incompetent PrPs efficiently cause DNI but others do not, presumably depending on affinity for PrPSc and integrity of interaction interface. We utilized DNI to characterize the PrP-PrP interaction interface in cultured cells. We created a series of PrPs with internal deletions in the region between helix 1 and 2 and evaluated their DNI. We found an inverse correlation between deletion size and DNI which suggests that this region plays an important role in PrP-PrP interaction. We also found that such PrPs are subject to various cellular degradation pathways and that a fraction of them reaches the intracellular locale of prion conversion. Further investigation of such prion proteins might help elucidating the cellular mechanisms of the PrPC-PrPSc interaction.
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Affiliation(s)
- Yuzuru Taguchi
- Departments of Veterinary Sciences and of Molecular Biology, University of Wyoming, Laramie, Wyoming, United States of America.
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10
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Wu NW, Zhang J, Ciren D, Han Q, Chen LJ, Xu L, Yang HB. Construction of Supramolecular Pyrene-Modified Metallacycles via Coordination-Driven Self-Assembly and Their Spectroscopic Behavior. Organometallics 2013. [DOI: 10.1021/om301108s] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Nai-Wei Wu
- Shanghai Key Laboratory of Green
Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062,
People’s Republic of China
| | - Jing Zhang
- Shanghai Key Laboratory of Green
Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062,
People’s Republic of China
| | - Deji Ciren
- Department of Public Teaching, Tibet Agricultural and Animal Husbandry College, 8 Xueyuan Road, Linzhi,
Tibet 860000, People’s Republic of China
| | - Qing Han
- Shanghai Key Laboratory of Green
Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062,
People’s Republic of China
| | - Li-Jun Chen
- Shanghai Key Laboratory of Green
Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062,
People’s Republic of China
| | - Lin Xu
- Shanghai Key Laboratory of Green
Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062,
People’s Republic of China
| | - Hai-Bo Yang
- Shanghai Key Laboratory of Green
Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062,
People’s Republic of China
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11
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Liao TY, Lee LYL, Chen RPY. Leu138 in bovine prion peptide fibrils is involved in seeding discrimination related to codon 129 M/V polymorphism in the prion peptide seeding experiment. FEBS J 2011; 278:4351-61. [DOI: 10.1111/j.1742-4658.2011.08353.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Ji HF, Zhang HY. beta-sheet constitution of prion proteins. Trends Biochem Sci 2010; 35:129-34. [PMID: 20060302 DOI: 10.1016/j.tibs.2009.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 12/07/2009] [Accepted: 12/09/2009] [Indexed: 11/19/2022]
Abstract
Structural information regarding normal prion protein (PrP(C)) and the scrapie isoform (PrP(Sc)) is of vital importance for elucidating the pathogenesis of prion diseases (PDs). Despite successful determination of the three-dimensional structures of PrP(C), the structural details of PrP(Sc) remain elusive. Nevertheless, accumulated evidence indicates that beta-sheets comprise the basic building blocks of PrP(Sc). Consensus has been reached about the beta-sheet constitution of the N-terminus of PrP, but the constitution of C-terminal beta-sheets is heavily debated. By evaluating the most recent observations regarding the dynamics and structures of PrP, we propose that helix 2 is more likely than helices 1 and 3 to participate in beta-sheet formation. This hypothesis also provides clues to explaining an intriguing phenomenon in prion biology-the lack of PDs in non-mammals.
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Affiliation(s)
- Hong-Fang Ji
- Shandong Provincial Research Center for Bioinformatic Engineering and Technique, Center for Advanced Study, Shandong University of Technology, Zibo 255049, PR China.
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13
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Abstract
The crucial event in the development of transmissible spongiform encephalopathies (TSEs) is the conformational change of a host-encoded membrane protein - the cellular PrPC - into a disease associated, fibril-forming isoform PrPSc. This conformational transition from the α-helix-rich cellular form into the mainly β-sheet containing counterpart initiates an ‘autocatalytic’ reaction which leads to the accumulation of amyloid fibrils in the central nervous system (CNS) and to neurodegeneration, a hallmark of TSEs. The exact molecular mechanisms which lead to the conformational change are still unknown. It also remains to be brought to light how a polypeptide chain can adopt at least two stable conformations. This review focuses on structural aspects of the prion protein with regard to protein-protein interactions and the initiation of prion protein misfolding. It therefore highlights parts of the protein which might play a notable role in the conformational transition from PrPC to PrPSc and consequently in inducing a fatal chain reaction of protein misfolding. Furthermore, features of different proteins, which are able to adopt insoluble fibrillar states under certain circumstances, are compared to PrP in an attempt to understand the unique characteristics of prion diseases.
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Affiliation(s)
- L Kupfer
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1, Canada
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14
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Yamaguchi KI, Matsumoto T, Kuwata K. Critical region for amyloid fibril formation of mouse prion protein: unusual amyloidogenic properties of the helix 2 peptide. Biochemistry 2009; 47:13242-51. [PMID: 19053276 DOI: 10.1021/bi801562w] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To gain insight into the structural mechanism of the conformational conversion process of prion, we examined the potential amyloidogenic property of each secondary structural element in a mouse prion protein (mPrP) and discriminated their relative significance for the formation of amyloid fibrils. Although peptides corresponding to alpha-helix 2 and alpha-helix 3 (named H2 peptide and H3 peptide, respectively) formed the amyloid-like fibrils, their structures were quite different. H2 fibrils formed the ordered beta-sheet with the beta-turn conformation, and the resultant fibrils were long and straight. In contrast, H3 fibrils consisted of the beta-sheet with the random conformation, and the resultant fibrils were short and flexible. These properties are basically consistent with their hydrophobicity and beta-strand propensity profiles. To examine the cross reactivity between peptide fragments and full-length mPrP, we then carried out seeding experiments. While H2 seeds induced the formation of fibrils of full-length mPrP as quickly as full-length mPrP seeds, H3 seeds exhibited a long lag time. This implies that the region of alpha-helix 2 rather than alpha-helix 3 in mPrP has great potential for initiating fibril formation. As a whole, the alpha-helix 2 region would be crucial for the nucleation-dependent replication process of the prion protein.
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Affiliation(s)
- Kei-ichi Yamaguchi
- Center for Emerging Infectious Diseases, Gifu University, Yanagido 1-1, Gifu 501-1194, Japan
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15
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Graether SP, Sykes BD. Structural characterization of amyloidotic antifreeze protein fibrils and intermediates. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:1030-1033. [PMID: 19697237 DOI: 10.1080/15287390903084272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The propagation and detrimental effects of prion disease are thought to be associated with the amyloid-like prion fibrils or with other misfolded structures known as beta-oligomers. The freezing and thawing of high concentrations of an antifreeze protein result in fibrils that have morphological and structural properties similar to those of amyloid. The method to produce these amyloid-like fibrils is expanded upon in this study. Data showed that the C-terminal end of the protein retains its alpha-helical character even in the amyloid state, and that changing the pH of the protein solution from 4 to 8 resulted in gels that resemble the beta-oligomeric form. These interim results provide the conditions for further elucidating the structure of these fibrils and their intermediate states.
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Affiliation(s)
- Steffen P Graether
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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16
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Chowdhury RP, Vijayabaskar MS, Vishveshwara S, Chatterji D. Molecular mechanism of in vitro oligomerization of Dps from Mycobacterium smegmatis: mutations of the residues identified by "interface cluster" analysis. Biochemistry 2008; 47:11110-7. [PMID: 18826253 DOI: 10.1021/bi801158e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The irreversible dodecamerization of native Dps trimers from Mycobacterium smegmatis, in vitro, is known to be directly associated with the bimodal function of this protein. Hence it is important to explore this pathway at the molecular level. Two types of trimers, Trimer A (tA) and Trimer B (tB), can be derived from the dodecamer due to the inherent 3-fold symmetry of the spherical crystal structure. These derived trimers were expressed as protein structure graphs (PSGs) using the computed interaction strength among the residues. Interface clusters which were identified from PSGs allowed us to convincingly predict E146 and F47 for further mutation studies. Various single and double mutants were constructed and characterized. We were finally able to generate a single mutant F47E impaired in dodecamerization and a double mutant E146AF47E as native monomer in solution. These two observed results suggest that the two trimers are important for dodecamerization and that the residues selected are important for the structural stability of the protein in vitro.
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17
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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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18
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Abstract
We use discrete event stochastic simulations to characterize the parameter space of a model of icosahedral viral capsid assembly as functions of monomer-monomer binding rates. The simulations reveal a parameter space characterized by three major assembly mechanisms, a standard nucleation-limited monomer-accretion pathway and two distinct hierarchical assembly pathways, as well as unproductive regions characterized by kinetically trapped species. Much of the productive parameter space also consists of border regions between these domains where hybrid pathways are likely to operate. A simpler octamer system studied for comparison reveals three analogous pathways, but is characterized by much lesser sensitivity to parameter variations in contrast to the sharp changes visible in the icosahedral model. The model suggests that modest changes in assembly conditions, consistent with expected differences between in vitro and in vivo assembly environments, could produce substantial shifts in assembly pathways. These results suggest that we must be cautious in drawing conclusions about in vivo capsid self-assembly dynamics from theoretical or in vitro models, as the nature of the basic assembly mechanisms accessible to a system can substantially differ between simple and complex model systems, between theoretical models and simulation results, and between in vitro and in vivo assembly conditions.
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19
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Yu S, Yin S, Li C, Wong P, Chang B, Xiao F, Kang SC, Yan H, Xiao G, Tien P, Sy MS. Aggregation of prion protein with insertion mutations is proportional to the number of inserts. Biochem J 2007; 403:343-51. [PMID: 17187581 PMCID: PMC1874237 DOI: 10.1042/bj20061592] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mutation in the prion gene, PRNP, accounts for approx. 10-15% of human prion diseases. However, little is known about the mechanisms by which a mutant prion protein (PrP) causes disease. We compared the biochemical properties of a wild-type human prion protein, rPrP(C) (recombinant wild-type PrP), which has five octapeptide-repeats, with two recombinant human prion proteins with insertion mutations, one with three more octapeptide repeats, rPrP(8OR), and the other with five more octapeptide repeats, rPrP(10OR). We found that the insertion mutant proteins are more prone to aggregate, and the degree and kinetics of aggregation are proportional to the number of inserts. The octapeptide-repeat and alpha-helix 1 regions are important in aggregate formation, because aggregation is inhibited with monoclonal antibodies that are specific for epitopes in these regions. We also showed that a small amount of mutant protein could enhance the formation of mixed aggregates that are composed of mutant protein and wild-type rPrP(C). Accordingly, rPrP(10OR) is also more efficient in promoting the aggregation of rPrP(C) than rPrP(8OR). These findings provide a biochemical explanation for the clinical observations that the severity of the disease in patients with insertion mutations is proportional to the number of inserts, and thus have implications for the pathogenesis of inherited human prion disease.
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Affiliation(s)
- Shuiliang Yu
- *Department of Pathology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44120, U.S.A
| | - Shaoman Yin
- *Department of Pathology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44120, U.S.A
| | - Chaoyang Li
- *Department of Pathology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44120, U.S.A
| | - Poki Wong
- *Department of Pathology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44120, U.S.A
| | - Binggong Chang
- *Department of Pathology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44120, U.S.A
| | - Fan Xiao
- *Department of Pathology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44120, U.S.A
| | - Shin-Chung Kang
- *Department of Pathology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44120, U.S.A
| | - Huimin Yan
- *Department of Pathology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44120, U.S.A
- †Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - Gengfu Xiao
- †Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - Po Tien
- †Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, People's Republic of China
- ‡Institute of Microbiology, Chinese Academy of Science, Beijing 100080, People's Republic of China
| | - Man-Sun Sy
- *Department of Pathology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44120, U.S.A
- To whom correspondence should be addressed (email )
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20
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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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21
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Fasano C, Campana V, Zurzolo C. Prions: protein only or something more? Overview of potential prion cofactors. J Mol Neurosci 2007; 29:195-214. [PMID: 17085779 DOI: 10.1385/jmn:29:3:195] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Revised: 11/30/1999] [Accepted: 02/03/2006] [Indexed: 12/12/2022]
Abstract
Transmissible spongiform encephalopathies (TSEs) in humans and animals are attributed to protein-only infectious agents, called prions. Prions have been proposed to arise from the conformational conversion of the cellular protein PrP(C) into a misfolded form (e.g., PrP(Sc) for scrapie), which precipitates into aggregates and fibrils. It has been proposed that the conversion process is triggered by the interaction of the infectious form (PrP(Sc)) with the cellular form (PrP(C)) or might result from a mutation in the gene for PrP(C). However, until recently, all efforts to reproduce this process in vitro had failed, suggesting that host factors are necessary for prion replication. In this review we discuss recent findings such as the cellular factors that might be involved in the conformational conversion of prion proteins and the potential mechanisms by which they could operate.
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Affiliation(s)
- Carlo Fasano
- Unité de Trafic Membranaire et Pathogénése, Institut Pasteur, 75724 Paris Cedex 15, France
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22
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Lee LYL, Chen RPY. Quantifying the sequence-dependent species barrier between hamster and mouse prions. J Am Chem Soc 2007; 129:1644-52. [PMID: 17243682 DOI: 10.1021/ja0667413] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prion diseases are transmissible neurodegenerative disorders. It is widely accepted that prions are the infectious agents responsible for disease transmission, and the sequence homology between the infectious prion and the host prion protein determines its transmission efficiency across species. However, previous studies have often reported different results regarding seeding efficiency, the efficiency of initiating amyloid propagation by adding pre-existing amyloid fibrils as seed. In the present study, we used synthetic peptides as a simple system to determine the sequence-dependent transmission barrier between hamster and mouse. We found that the heterologous seeding efficiency of hamster and mouse prion peptides was 4 times less than that of homologous seeding. Moreover, residue 139 was not the only residue in determining seeding efficiency. When the seed had Ile at this position, the homology at this position between seed and monomer determined the seeding efficiency. When the seed had Met at this position, homology at residues 109 and 112 determined the seeding efficiency.
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Affiliation(s)
- Lily Y-L Lee
- Contribution from the Institute of Biological Chemistry, Academia Sinica, No. 128, Sec 2, Academia Road, Nankang, Taipei 115, Taiwan, Republic of China
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23
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Watzlawik J, Skora L, Frense D, Griesinger C, Zweckstetter M, Schulz-Schaeffer WJ, Kramer ML. Prion protein helix1 promotes aggregation but is not converted into beta-sheet. J Biol Chem 2006; 281:30242-50. [PMID: 17012240 DOI: 10.1074/jbc.m605141200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prion diseases are caused by the aggregation of the native alpha-helical prion protein PrP(C) into its pathological beta-sheet-rich isoform PrP(Sc). In current models of PrP(Sc), helix1 is assumed to be preferentially converted into beta-sheet during aggregation of PrP(C). This was supported by the NMR structure of PrP(C) since, in contrast to the isolated helix1, helix2 and helix3 are connected by a small loop and are additionally stabilized by an interhelical disulfide bond. However, helix1 is extremely hydrophilic and has a high helix propensity. This prompted us to investigate the role of helix1 in prion aggregation using humPrP(23-159) including helix1 (144-156) compared with the C-terminal-truncated isoform humPrP(23-144) corresponding to the pathological human stop mutations Q160Stop and Y145Stop, respectively. Most unexpectedly, humPrP(23-159) aggregated significantly faster compared with the truncated fragment humPrP(23-144), clearly demonstrating that helix1 is involved in the aggregation process. However, helix1 is not resistant to digestion with proteinase K in fibrillar humPrP(23-159), suggesting that helix1 is not converted to beta-sheet. This is confirmed by Fourier transformation infrared spectroscopy since there is almost no difference in beta-sheet content of humPrP(23-159) fibrils compared with humPrP(23-144). In conclusion, we provide strong direct evidence that in contrast to earlier assumptions helix1 is not converted into beta-sheet during aggregation of PrP(C) to PrP(Sc).
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Affiliation(s)
- Jens Watzlawik
- Prion and Dementia Research Unit, Institute of Neuropathology, University of Goettingen, 37075 Goettingen, Germany
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24
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Abstract
Prion diseases are among the most intriguing illnesses. Despite their rare incidence, they have captured enormous attention from the scientific community and general public. One of the most hotly debated issues in these diseases is the nature of the infectious material. In recent years increasing evidence has emerged supporting the protein-only hypothesis of prion transmission. In this model PrPSc (the pathological isoform of the prion protein, PrPC) represents the sole component of the infectious particle. However, uncertainties about possible additional factors involved in the conversion of PrPC into PrPSc remain despite extensive attempts to isolate and characterize these elusive components. In this article, we review recent developments concerning the protein-only hypothesis as well as the possible involvement of cellular factors in PrPC to PrPSc conformational change and their influence on the pathogenesis of prion diseases.
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Affiliation(s)
- K. Abid
- Protein Misfolding Disorders Lab, George and Cynthia Mitchell Center for Alzheimer’s Disease Research, Departments of Neurology, Neuroscience and Cell Biology and Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas 77555 USA
| | - C. Soto
- Protein Misfolding Disorders Lab, George and Cynthia Mitchell Center for Alzheimer’s Disease Research, Departments of Neurology, Neuroscience and Cell Biology and Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas 77555 USA
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25
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Shiraishi N, Utsunomiya H, Nishikimi M. Combination of NADPH and copper ions generates proteinase K-resistant aggregates from recombinant prion protein. J Biol Chem 2006; 281:34880-7. [PMID: 16990274 DOI: 10.1074/jbc.m606581200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent studies have demonstrated that the octapeptide repeats of the N-terminal region of prion protein may be responsible for de novo generation of infectious prions in the absence of template. Here we demonstrate that PrP-(23-98), an N-terminal portion of PrP, is converted to aggregates upon incubation with NADPH and copper ions. Other pyridine nucleotides possessing a phosphate group on the adenine-linked ribose moiety (the reduced form of nicotinamide adenine dinucleotide 3'-phosphate, nicotinic acid adenine dinucleotide phosphate, and NADP) were also effective in promoting aggregation, but NADH and NAD had no effect. The aggregation was attenuated by the metal chelator EDTA or by modification of histidyl residues with diethyl pyrocarbonate. The aggregates are amyloid-like as judged by the binding of thioflavin T, a fluorescent probe for amyloid, but do not exhibit fibrillar structures according to electron micrography. Interestingly the aggregates were resistant to proteinase K digestion. Likewise NADPH and zinc ions caused aggregation of PrP-(23-98), but the resulting aggregates were susceptible to degradation by proteinase K. Upon incubation with NADPH and copper ions, the full-length molecule PrP-(23-231) also formed proteinase K-resistant amyloid-like aggregates. Because it is possible that PrP, NADPH, and copper ions could associate in certain tissues, the aggregation observed in this study may be involved in prion initiation especially in the nonfamilial types of prion diseases.
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Affiliation(s)
- Noriyuki Shiraishi
- Department of Biochemistry and Central Research Laboratory, Wakayama Medical University, Wakayama 641-8509, Japan.
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26
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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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27
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Martins SM, Frosoni DJ, Martinez AMB, De Felice FG, Ferreira ST. Formation of soluble oligomers and amyloid fibrils with physical properties of the scrapie isoform of the prion protein from the C-terminal domain of recombinant murine prion protein mPrP-(121-231). J Biol Chem 2006; 281:26121-8. [PMID: 16844683 DOI: 10.1074/jbc.m605367200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prion diseases are fatal neurodegenerative disorders associated with conformational conversion of the cellular prion protein, PrP(C), into a misfolded, protease-resistant form, PrP(Sc). Here we show, for the first time, the oligomerization and fibrillization of the C-terminal domain of murine PrP, mPrP-(121-231), which lacks the entire unstructured N-terminal domain of the protein. In particular, the construct we used lacks amino acid residues 106-120 from the so-called amyloidogenic core of PrP (residues 106-126). Amyloid formation was accompanied by acquisition of resistance to proteinase K digestion. Aggregation of mPrP-(121-231) was investigated using a combination of biophysical and biochemical techniques at pH 4.0, 5.5, and 7.0 and at 37 and 65 degrees C. Under partially denaturing conditions (65 degrees C), aggregates of different morphologies ranging from soluble oligomers to mature amyloid fibrils of mPrP-(121-231) were formed. Transmission electron microscopy analysis showed that roughly spherical aggregates were readily formed when the protein was incubated at pH 5.5 and 65 degrees C for 1 h, whereas prolonged incubation led to the formation of mature amyloid fibrils. Samples incubated at 65 degrees C at pH 4.0 or 7.0 presented an initial mixture of oligomers and protofibrils or fibrils. Electrophoretic analysis of samples incubated at 65 degrees C revealed formation of sodium dodecyl sulfate-resistant oligomers (dimers, trimers, and tetramers) and higher molecular weight aggregates of mPrP-(121-231). These results demonstrate that formation of an amyloid form with physical properties of PrP(Sc) can be achieved in the absence of the flexible N-terminal domain and, in particular, of residues 106-120 of PrP and does not require other cellular factors or a PrP(Sc) template.
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Affiliation(s)
- Samantha M Martins
- Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21944-590, Brazil
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28
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Vendrely C, Valadié H, Bednarova L, Cardin L, Pasdeloup M, Cappadoro J, Bednar J, Rinaudo M, Jamin M. Assembly of the full-length recombinant mouse prion protein I. Formation of soluble oligomers. Biochim Biophys Acta Gen Subj 2005; 1724:355-66. [PMID: 15975719 DOI: 10.1016/j.bbagen.2005.05.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 05/12/2005] [Accepted: 05/16/2005] [Indexed: 11/28/2022]
Abstract
The conversion of a monomeric alpha-helix-rich isoform to multimeric beta-sheet-rich isoforms is a prominent feature of the conversion between PrP(C) and PrP(SC). We mimicked this process in vitro by exposing an unglycosylated recombinant form of the full-length mouse prion protein ((Mo)PrP(23-231)) to an acidic pH, at 37 degrees C, and we monitored the kinetics of conformational change and assembly. In these conditions, monomeric (Mo)PrP(23-231) converts slowly to two ensembles of soluble oligomers that are separated by size exclusion chromatography. The larger oligomers (I) are unstable, and their formation involves almost no change in secondary structure content. The smaller oligomers (II) form stable spherical or annular particles containing between 8 and 15 monomers as determined by multi-angle laser light scattering (MALLS). Their formation is concomitant with the main, thought limited, change in the secondary structure content (10%) seen by Fourier Transform Infrared (FTIR) spectroscopy. Even if these oligomers conserve a large part of the secondary structure of monomeric PrP, they exhibit amyloid features with the appearance of intermolecular beta-structure as revealed by the appearance of an IR band below 1620 cm(-1).
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Affiliation(s)
- Charlotte Vendrely
- Laboratoire de Biophysique Moléculaire et Cellulaire, Université Joseph Fourier, BMC/DRDC, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
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29
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Castilla J, Saá P, Hetz C, Soto C. In vitro generation of infectious scrapie prions. Cell 2005; 121:195-206. [PMID: 15851027 DOI: 10.1016/j.cell.2005.02.011] [Citation(s) in RCA: 597] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Revised: 12/20/2004] [Accepted: 02/11/2005] [Indexed: 11/22/2022]
Abstract
Prions are unconventional infectious agents responsible for transmissible spongiform encephalopathy (TSE) diseases. They are thought to be composed exclusively of the protease-resistant prion protein (PrPres) that replicates in the body by inducing the misfolding of the cellular prion protein (PrPC). Although compelling evidence supports this hypothesis, generation of infectious prion particles in vitro has not been convincingly demonstrated. Here we show that PrPC --> PrPres conversion can be mimicked in vitro by cyclic amplification of protein misfolding, resulting in indefinite amplification of PrPres. The in vitro-generated forms of PrPres share similar biochemical and structural properties with PrPres derived from sick brains. Inoculation of wild-type hamsters with in vitro-produced PrPres led to a scrapie disease identical to the illness produced by brain infectious material. These findings demonstrate that prions can be generated in vitro and provide strong evidence in support of the protein-only hypothesis of prion transmission.
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Affiliation(s)
- Joaquín Castilla
- Department of Neurology, University of Texas Medical Branch, Galveston, Texas 77555, USA
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30
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Bocharova OV, Breydo L, Parfenov AS, Salnikov VV, Baskakov IV. In vitro conversion of full-length mammalian prion protein produces amyloid form with physical properties of PrP(Sc). J Mol Biol 2004; 346:645-59. [PMID: 15670611 DOI: 10.1016/j.jmb.2004.11.068] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 07/08/2004] [Accepted: 11/10/2004] [Indexed: 10/26/2022]
Abstract
The "protein only" hypothesis postulates that the infectious agent of prion diseases, PrP(Sc), is composed of the prion protein (PrP) converted into an amyloid-specific conformation. However, cell-free conversion of the full-length PrP into the amyloid conformation has not been achieved. In an effort to understand the mechanism of PrP(Sc) formation, we developed a cell-free conversion system using recombinant mouse full-length PrP with an intact disulfide bond (rPrP). We demonstrate that rPrP will convert into the beta-sheet-rich oligomeric form at highly acidic pH (<5.5) and at high concentrations, while at slightly acidic or neutral pH (>5.5) it assembles into the amyloid form. As judged from electron microscopy, the amyloid form had a ribbon-like assembly composed of two non-twisted filaments. In contrast to the formation of the beta-oligomer, the conversion to the amyloid occurred at concentrations close to physiological and displayed key features of an autocatalytic process. Moreover, using a shortened rPrP consisting of 106 residues (rPrP 106, deletions: Delta23-88 and Delta141-176), we showed that the in vitro conversion mimicked a transmission barrier observed in vivo. Furthermore, the amyloid form displayed a remarkable resistance to proteinase K (PK) and produced a PK-resistant core identical with that of PrP(Sc). Fourier transform infrared spectroscopy analyses showed that the beta-sheet-rich core of the amyloid form remained intact upon PK-digestion and accounted for the extremely high thermal stability. Electron and real-time fluorescent microscopy revealed that proteolytic digestion induces either aggregation of the amyloid ribbons into large clumps or further assembly into fibrils composed of several ribbons. Fibrils composed of ribbons were very fragile and had a tendency to fragment into short pieces. Remarkably, the amyloid form treated with PK preserved high seeding activity. Our work supports the protein only hypothesis of prion propagation and demonstrates that formation of the amyloid form that recapitulates key physical properties of PrP(Sc) can be achieved in vitro in the absence of cellular factors or a PrP(Sc) template.
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Affiliation(s)
- Olga V Bocharova
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, MD 21201, USA
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31
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Tahiri-Alaoui A, Gill AC, Disterer P, James W. Methionine 129 Variant of Human Prion Protein Oligomerizes More Rapidly than the Valine 129 Variant. J Biol Chem 2004; 279:31390-7. [PMID: 15131108 DOI: 10.1074/jbc.m401754200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human PrP gene (PRNP) has two common alleles that encode either methionine or valine at codon 129. This polymorphism modulates disease susceptibility and phenotype of human transmissible spongiform encyphalopathies, but the molecular mechanism by which these effects are mediated remains unclear. Here, we compared the misfolding pathway that leads to the formation of beta-sheet-rich oligomeric isoforms of the methionine 129 variant of PrP to that of the valine 129 variant. We provide evidence for differences in the folding behavior between the two variants at the early stages of oligomer formation. We show that Met(129) has a higher propensity to form beta-sheet-rich oligomers, whereas Val(129) has a higher tendency to fold into alpha-helical-rich monomers. An equimolar mixture of both variants displayed an intermidate folding behavior. We show that the oligomers of both variants are initially a mixture of alpha- and beta-rich conformers that evolve with time to an increasingly homogeneous beta-rich form. This maturation process, which involves no further change in proteinase K resistance, occurs more rapidly in the Met(129) form than the Val(129) form. Although the involvement of such beta-rich oligomers in prion pathogenesis is speculative, the misfolding behavior could, in part, explain the higher susceptibility of individuals that are methionine homozygote to both sporadic and variant Creutzfeldt-Jakob disease.
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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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32
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May BCH, Govaerts C, Prusiner SB, Cohen FE. Prions: so many fibers, so little infectivity. Trends Biochem Sci 2004; 29:162-5. [PMID: 15124628 DOI: 10.1016/j.tibs.2004.02.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Barnaby C H May
- Institute for Neurodegenerative Diseases, University of California-San Francisco, 513 Parnassus Avenue, HSE-774, San Francisco, CA 94143-0518, USA.
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Tremblay P, Ball HL, Kaneko K, Groth D, Hegde RS, Cohen FE, DeArmond SJ, Prusiner SB, Safar JG. Mutant PrPSc conformers induced by a synthetic peptide and several prion strains. J Virol 2004; 78:2088-99. [PMID: 14747574 PMCID: PMC369494 DOI: 10.1128/jvi.78.4.2088-2099.2004] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gerstmann-Sträussler-Scheinker (GSS) disease is a dominantly inherited, human prion disease caused by a mutation in the prion protein (PrP) gene. One mutation causing GSS is P102L, denoted P101L in mouse PrP (MoPrP). In a line of transgenic mice denoted Tg2866, the P101L mutation in MoPrP produced neurodegeneration when expressed at high levels. MoPrP(Sc)(P101L) was detected both by the conformation-dependent immunoassay and after protease digestion at 4 degrees C. Transmission of prions from the brains of Tg2866 mice to those of Tg196 mice expressing low levels of MoPrP(P101L) was accompanied by accumulation of protease-resistant MoPrP(Sc)(P101L) that had previously escaped detection due to its low concentration. This conformer exhibited characteristics similar to those found in brain tissue from GSS patients. Earlier, we demonstrated that a synthetic peptide harboring the P101L mutation and folded into a beta-rich conformation initiates GSS in Tg196 mice (29). Here we report that this peptide-induced disease can be serially passaged in Tg196 mice and that the PrP conformers accompanying disease progression are conformationally indistinguishable from MoPrP(Sc)(P101L) found in Tg2866 mice developing spontaneous prion disease. In contrast to GSS prions, the 301V, RML, and 139A prion strains produced large amounts of protease-resistant PrP(Sc) in the brains of Tg196 mice. Our results argue that MoPrP(Sc)(P101L) may exist in at least several different conformations, each of which is biologically active. Such conformations occurred spontaneously in Tg2866 mice expressing high levels of MoPrP(C)(P101L) as well as in Tg196 mice expressing low levels of MoPrP(C)(P101L) that were inoculated with brain extracts from ill Tg2866 mice, with a synthetic peptide with the P101L mutation and folded into a beta-rich structure, or with prions recovered from sheep with scrapie or cattle with bovine spongiform encephalopathy.
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Affiliation(s)
- Patrick Tremblay
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California, San Francisco, California 94143, USA
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Baskakov IV, Legname G, Gryczynski Z, Prusiner SB. The peculiar nature of unfolding of the human prion protein. Protein Sci 2004; 13:586-95. [PMID: 14767078 PMCID: PMC2286731 DOI: 10.1110/ps.03457204] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2003] [Revised: 10/31/2003] [Accepted: 11/10/2003] [Indexed: 10/26/2022]
Abstract
Spontaneous conformational transition of the prion protein from an alpha-helical isoform to a beta-sheet-rich isoform underlies the pathogenesis of sporadic prion diseases. To study the rate-limiting steps of spontaneous conversion, the formation of amyloid fibrils by the recombinant human PrP C-terminal fragment spanning residues 90-231 (recPrP) was monitored in the presence of urea. The kinetics of spontaneous fibril formation displayed sigmoidal behavior involving a lag phase. The shortest lag phase was observed at partially denaturing conditions, close to the concentration of urea corresponding to the middle point of unfolding. This result indicates that unfolding intermediates may be important for the conversion. To test whether unfolding intermediates are formed, we employed size-exclusion chromatography and circular dichroism spectroscopy to monitor urea denaturation of recPrP. Both techniques showed a single sigmoidal transition with very similar thermodynamic parameters of denaturation and that the transition can be described by a simple equilibrium between folded and denatured states. Detailed analyses of data, however, revealed that the dimensions of both the native and denatured species gradually increases with urea. Expansion of the native species is also accompanied by an increase in efficiency of the energy transfer from a single Trp residue to 1-anilinonaphthalene-8-sulfonate dye as measured by fluorescence. These data illustrate that thermodynamic character of the native ensemble changes gradually with environmental conditions. Such behavior is consistent with the thermodynamically variable model, and may be linked to the ability of PrP to adopt distinct abnormal conformations under pathologic conditions.
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Affiliation(s)
- Ilia V Baskakov
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 W. Lombard Street, Baltimore, MD 21201, USA.
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35
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Farrelly PV, Kenna BL, Laohachai KL, Bahadi R, Salmona M, Forloni G, Kourie JI. Quinacrine blocks PrP (106-126)-formed channels. J Neurosci Res 2004; 74:934-41. [PMID: 14648599 DOI: 10.1002/jnr.10849] [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: 12/24/2022]
Abstract
We investigated the action of the acridine derivative, quinacrine (QC), which has been shown to act as a noncompetitive channel inhibitor. The main effects of QC are voltage- and concentration-dependent changes in the kinetics of the prion protein fragment (PrP[106-126])-formed cation channels. The current-voltage relationships show that the maximal current (I) was not affected whereas the physiologically important mean current (I') was reduced as a result of changes in channel kinetics. These findings suggest that QC acts on the open state of the channels. The half-inhibitory concentration (IC50) for the dose-dependent effects of [QC]cis on the kinetic parameters of the PrP(106-126)-formed cation channel shows a reduction in the ratios Po(QC)/Po, Fo(QC)/Fo, and To(QC)/To, whereas Tc(QC)/Tc increases. Of these ratios, Po(QC)/Po was more sensitive than the others. The corresponding IC50 for these ratios were 51, 94, 86, and 250 microM QC, respectively. The QC-induced changes in the kinetic parameters were more apparent at positive voltages. IC50 values for Po were 95, 75, and 51 microM at +20, +80, and +140 mV, respectively. The fact that QC induced changes in the kinetics of this channel, although the conductance of the channel remained unchanged, indicates that QC may bind at the mouth of the channel via a mechanism known as fast channel block. The QC-induced changes in the kinetic parameters of this channel suggest that they are pathophysiologically significant because these channels could be the mechanisms by which amyloids induce membrane damage in vivo.
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Affiliation(s)
- Peter V Farrelly
- Membrane Transport Group, Department of Chemistry, The Faculties, The Australian National University, Canberra City, Australian Capital Territory, Australia
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36
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Ziegler J, Sticht H, Marx UC, Müller W, Rösch P, Schwarzinger S. CD and NMR studies of prion protein (PrP) helix 1. Novel implications for its role in the PrPC-->PrPSc conversion process. J Biol Chem 2003; 278:50175-81. [PMID: 12952977 DOI: 10.1074/jbc.m305234200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The conversion of prion helix 1 from an alpha-helical into an extended conformation is generally assumed to be an essential step in the conversion of the cellular isoform PrPC of the prion protein to the pathogenic isoform PrPSc. Peptides encompassing helix 1 and flanking sequences were analyzed by nuclear magnetic resonance and circular dichroism. Our results indicate a remarkably high instrinsic helix propensity of the helix 1 region. In particular, these peptides retain significant helicity under a wide range of conditions, such as high salt, pH variation, and presence of organic co-solvents. As evidenced by a data base search, the pattern of charged residues present in helix 1 generally favors helical structures over alternative conformations. Because of its high stability against environmental changes, helix 1 is unlikely to be involved in the initial steps of the pathogenic conformational change. Our results implicate that interconversion of helix 1 is rather representing a barrier than a nucleus for the PrPC-->PrPSc conversion.
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Affiliation(s)
- Jan Ziegler
- Lehrstuhl für Biopolymere, Universität Bayreuth, 95447 Bayreuth, Germany
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37
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Sokolowski F, Modler AJ, Masuch R, Zirwer D, Baier M, Lutsch G, Moss DA, Gast K, Naumann D. Formation of critical oligomers is a key event during conformational transition of recombinant syrian hamster prion protein. J Biol Chem 2003; 278:40481-92. [PMID: 12917432 DOI: 10.1074/jbc.m304391200] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have investigated the conformational transition and aggregation process of recombinant Syrian hamster prion protein (SHaPrP90-232) by Fourier transform infrared spectroscopy, circular dichroism spectroscopy, light scattering, and electron microscopy under equilibrium and kinetic conditions. SHaPrP90-232 showed an infrared absorbance spectrum typical of proteins with a predominant alpha-helical structure both at pH 7.0 and at pH 4.2 in the absence of guanidine hydrochloride. At pH 4.2 and destabilizing conditions (0.3-2 m guanidine hydrochloride), the secondary structure of SHaPrP90-232 was transformed to a strongly hydrogen-bonded, most probably intermolecularly arranged antiparallel beta-sheet structure as indicated by dominant amide I band components at 1620 and 1691 cm-1. Kinetic analysis of the transition process showed that the decrease in alpha-helical structures and the increase in beta-sheet structures occurred concomitantly according to a bimolecular reaction. However, the concentration dependence of the corresponding rate constant pointed to an apparent third order reaction. No beta-sheet structure was formed within the dead time (190 ms) of the infrared experiments. Light scattering measurements revealed that the structural transition of SHaPrP90-232 was accompanied by formation of oligomers, whose size was linearly dependent on protein concentration. Extrapolation to zero protein concentration yielded octamers as the smallest oligomers, which are considered as "critical oligomers." The small oligomers showed spherical and annular shapes in electron micrographs. Critical oligomers seem to play a key role during the transition and aggregation process of SHaPrP90-232. A new model for the structural transition and aggregation process of the prion protein is described.
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Bahadi R, Farrelly PV, Kenna BL, Kourie JI, Tagliavini F, Forloni G, Salmona M. Channels formed with a mutant prion protein PrP(82-146) homologous to a 7-kDa fragment in diseased brain of GSS patients. Am J Physiol Cell Physiol 2003; 285:C862-72. [PMID: 12814912 DOI: 10.1152/ajpcell.00077.2003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A major prion protein (PrP) mutant that forms amyloid fibrils in the diseased brain of patients with Gerstmann-Sträussler-Scheinker syndrome (GSS) is a fragment of 7 kDa spanning from residues 81-82 to 144-153 of PrP. Analysis of ionic membrane currents, recorded with a lipid bilayer technique, revealed that the wild-type fragment PrP(82-146) WT and the partially scrambled PrP(82-146) (127-146) SC are capable of forming heterogeneous ion channels that are similar to those channels formed with PrP(106-126). In contrast, PrP(82-146) peptides in which the region from residue 106 to 126 had been scrambled (SC) showed a reduction in interaction with lipid membranes and did not form channels. The PrP(82-146) WT- and PrP(82-146) (127-146) SC-formed cation channels with fast kinetics are Cu2+ sensitive and rifampicin (RIF) insensitive, whereas the time-dependent inactivating channels formed by these same peptides are both Cu2+ and RIF insensitive. The presence of RIF in the solution before the addition of PrP(82-146) WT or PrP(82-146) (127-146) SC affected their incorporation into the lipid bilayers. PrP(82-146) WT and PrP(82-146) (127-146) SC fast cation channels formed in the presence of RIF appeared in an electrically semisilent state or an inactivated state. Increasing [Cd2+]cis enhanced the incorporation of PrP(82-146) WT and PrP(82-146) (127-146) SC channels formed in the presence of RIF. We conclude that the major PrP mutant fragment in the diseased brain of GSS patients is prone to form channels in neuronal membranes, causing their dysfunction. We propose that Cd2+ may accentuate the neurotoxicity of this channel-forming PrP fragment by enhancing its incorporation into the membrane.
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Affiliation(s)
- Randa Bahadi
- Membrane Transport Group, Department of Chemistry, The Faculties, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
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39
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Ryou C, Prusiner SB, Legname G. Cooperative binding of dominant-negative prion protein to kringle domains. J Mol Biol 2003; 329:323-33. [PMID: 12758079 DOI: 10.1016/s0022-2836(03)00342-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conversion of the cellular prion protein (PrP(C)) to the pathogenic isoform (PrP(Sc)) is a major biochemical alteration in the progression of prion disease. This conversion process is thought to require interaction between PrP(C) and an as yet unidentified auxiliary factor, provisionally designated protein X. In searching for protein X, we screened a phage display cDNA expression library constructed from prion-infected neuroblastoma (ScN2a) cells and identified a kringle protein domain using full-length recombinant mouse PrP (recMoPrP(23-231), hereafter recMoPrP) expressing a dominant-negative mutation at codon 218 (recMoPrP(Q218K)). In vitro binding analysis using ELISA verified specific interaction of recMoPrP to kringle domains (K(1+2+3)) with higher binding by recMoPrP(Q218K) than by full-length recMoPrP without the mutation. This interaction was confirmed by competitive binding analysis, in which the addition of either a specific anti-kringle antibody or L-lysine abolished the interaction. Biochemical studies of the interactions between K(1+2+3) and various concentrations of both recMoPrP molecules demonstrated binding in a dose-dependent manner. A Hill plot analysis of the data indicates positive cooperative binding of both recMoPrP(Q218K) and recMoPrP to K(1+2+3) with stronger binding by recMoPrP(Q218K). Using full-length and an N-terminally truncated MoPrP(89-231), we demonstrate that N-terminal sequences enable PrP to bind strongly to K(1+2+3). Further characterization with truncated MoPrP(89-231) refolded in different conformations revealed that both alpha-helical and beta-sheet conformations bind to K(1+2+3). Our data demonstrate specific, high-affinity binding of a dominant-negative PrP as well as binding of other PrPs to K(1+2+3). The relevance of such interactions during prion pathogenesis remains to be established.
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Affiliation(s)
- Chongsuk Ryou
- Institute for Neurodegenerative Diseases, University of California, San Francisco 94143-0518, USA
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40
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Concepcion GP, Padlan EA. Are humans getting 'mad-cow disease' from eating beef, or something else? Med Hypotheses 2003; 60:699-701. [PMID: 12710905 DOI: 10.1016/s0306-9877(03)00025-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Bovine spongiform encephalopathy (BSE) or 'mad-cow disease' is believed to have been caused by the consumption of scrapie-infected sheep matter that had been added to cattle feed. BSE is then believed to have been transmitted to humans by the consumption of infected beef. We have compared the sequences of human and various animal prion proteins with regards to the fragments that could result from gastric digestion. We noted the close similarity of the sequences of human and rodent prion proteins in a peptic fragment that corresponds very closely to one that had been shown by others to be protease resistant and infective. Since rats and mice are known to be susceptible to prion disease, we propose that ingestion of infected rodent parts, possibly droppings, may be a possible mode of transmission of scrapie or BSE to humans.
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Affiliation(s)
- G P Concepcion
- Marine Science Institute, College of Science, University of the Philippines, Diliman, Quezon City, Philippines
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41
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Tahiri-Alaoui A, Bouchard M, Zurdo J, James W. Competing intrachain interactions regulate the formation of beta-sheet fibrils in bovine PrP peptides. Protein Sci 2003; 12:600-8. [PMID: 12592030 PMCID: PMC2312434 DOI: 10.1110/ps.0236703] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
At the heart of the pathogenesis of transmissible spongiform encephalopathies (TSEs), such as BSE, scrapie, and Creutzfeldt-Jakob disease, lies a poorly understood structural rearrangement of PrP, an abundant glycoprotein of the nervous and lymphoid systems. The normal form (PrP(C)), rich in alpha-helix, converts into an aberrant beta-sheet-dominated form (PrP(Sc)), which seems to be at the center of the pathotoxic symptoms observed in TSEs. To understand this process better at a molecular level, we have studied the interactions between different peptides derived from bovine PrP and their structural significance. We show that two unstructured peptides derived from the central region of bovine PrP, residues 115-133 and 140-152, respectively, interact stoichiometrically under physiological conditions to generate beta-sheet-dominated fibrils. However, when both peptides are incubated in the presence of a third peptide derived from an adjoining alpha-helical region (residues 153-169), the formation of beta-sheet-rich fibrils is abolished. These data indicate that native PrP(C) helix 1 might inhibit the strong intrinsic beta-sheet-forming propensity of sequences immediately N-terminal to the globular core of PrP(C), by keeping in place intrachain interactions that would prevent these amyloidogenic regions from triggering aggregation. Moreover, these results indicate new ways in which PrP(Sc) formation could be prevented.
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42
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Feughelman M, Willis BK. Potential involvement of copper and thiol-disulphide interchange in prion proteins' conformational conversion. Med Hypotheses 2002; 59:321-4. [PMID: 12208161 DOI: 10.1016/s0306-9877(02)00178-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The prion protein PrP(C) in transmissible spongiform encephalopathy converts to the pathogenic isoform PrP(Sc) containing less alpha-helical structure and a greater beta-pleated sheet content. The stability of PrP(C) protein is partly dependent on the disulphide bond between two alpha-helices designated B and C. Further stability could arise from ligand complexes of Cu(II) ions formed with carboxylic acid side chains in PrP(C). Electron spin resonance (E.S.R.) spectra and atomic absorption measurements have shown for alpha-keratin that the formation of ligands by Cu(II) is 10(2) more rapid than interaction of Cu(II) with ionised thiols X-S(-) which form X-S-Cu(+). X-S(-) destabilises disulphide bonds by thiol-disulphide interchange. When insufficient Cu(II) is present to form ligands with all available sites in PrP(C) then unblocked X-S(-) groups could potentially destabilise the disulphide bonds by thiol-disulphide interchange followed by reformation of the disulphide bond in the beta form of PrP(Sc) and the release of X-S(-) to interact with other PrP(C).
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Affiliation(s)
- M Feughelman
- University of New South Wales, Sydney, New South Wales, Australia
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43
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Kirkitadze MD, Bitan G, Teplow DB. Paradigm shifts in Alzheimer's disease and other neurodegenerative disorders: the emerging role of oligomeric assemblies. J Neurosci Res 2002; 69:567-77. [PMID: 12210822 DOI: 10.1002/jnr.10328] [Citation(s) in RCA: 456] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alzheimer's disease (AD) is a progressive, neurodegenerative disorder characterized by amyloid deposition in the cerebral neuropil and vasculature. These amyloid deposits comprise predominantly fragments and full-length (40 or 42 residue) forms of the amyloid beta-protein (Abeta) organized into fibrillar assemblies. Compelling evidence indicates that factors that increase overall Abeta production or the ratio of longer to shorter forms, or which facilitate deposition or inhibit elimination of amyloid deposits, cause AD or are risk factors for the disease. In vitro studies have demonstrated that fibrillar Abeta has potent neurotoxic effects on cultured neurons. In vivo experiments in non-human primates have demonstrated that Abeta fibrils directly cause pathologic changes, including tau hyperphosphorylation. In concert with histologic studies revealing a lack of tissue injury in areas of the neuropil in which non-fibrillar deposits were found, these data suggested that fibril assembly was a prerequisite for Abeta-mediated neurotoxicity in vivo. Recently, however, both in vitro and in vivo studies have revealed that soluble, oligomeric forms of Abeta also have potent neurotoxic activities, and in fact, may be the proximate effectors of the neuronal injury and death occurring in AD. A paradigm shift is thus emerging that necessitates the reevaluation of the relative importance of polymeric (fibrillar) vs. oligomeric assemblies in the pathobiology of AD. In addition to AD, an increasing number of neurodegenerative disorders, including Parkinson's disease, familial British dementia, familial amyloid polyneuropathy, amyotrophic lateral sclerosis, and prion diseases, are associated with abnormal protein assembly processes. The archetypal features of the assembly-dependent neuropathogenetic effects of Abeta may thus be of relevance not only to AD but to these other disorders as well.
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Bonetto V, Massignan T, Chiesa R, Morbin M, Mazzoleni G, Diomede L, Angeretti N, Colombo L, Forloni G, Tagliavini F, Salmona M. Synthetic miniprion PrP106. J Biol Chem 2002; 277:31327-34. [PMID: 12058037 DOI: 10.1074/jbc.m203275200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Elucidation of structure and biological properties of the prion protein scrapie (PrP(Sc)) is fundamental to an understanding of the mechanism of conformational transition of cellular (PrP(C)) into disease-specific isoforms and the pathogenesis of prion diseases. Unfortunately, the insolubility and heterogeneity of PrP(Sc) have limited these studies. The observation that a construct of 106 amino acids (termed PrP106 or miniprion), derived from mouse PrP and containing two deletions (Delta 23-88, Delta 141-176), becomes protease-resistant when expressed in scrapie-infected neuroblastoma cells and sustains prion replication when expressed in PrP(0/0) mice prompted us to generate a corresponding synthetic peptide (sPrP106) to be used for biochemical and cell culture studies. sPrP106 was obtained successfully with a straightforward procedure, which combines classical stepwise solid phase synthesis with a purification strategy based on transient labeling with a lipophilic chromatographic probe. sPrP106 readily adopted a beta-sheet structure, aggregated into branched filamentous structures without ultrastructural and tinctorial properties of amyloid, exhibited a proteinase K-resistant domain spanning residues 134-217, was highly toxic to primary neuronal cultures, and induced a remarkable increase in membrane microviscosity. These features are central properties of PrP(Sc) and make sPrP106 an excellent tool for investigating the molecular basis of the conformational conversion of PrP(C) into PrP(Sc) and prion disease pathogenesis.
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Affiliation(s)
- Valentina Bonetto
- Dulbecco Telethon Institute, Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri, via Eritrea 62, Milan 20157, Italy.
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45
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Alonso DOV, An C, Daggett V. Simulations of biomolecules: Characterization of the early steps in the pH-induced conformational conversion of the hamster, bovine and human forms of the prion protein. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2002; 360:1165-1178. [PMID: 12804272 DOI: 10.1098/rsta.2002.0986] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
As computer power increases, so too does the range of interesting biomolecular phenomena and properties that can be simulated. It is now possible to simulate complicated protein conformational changes at ambient or physiological temperatures. In this regard, we are attempting to map the conformational transitions of the normal, cellular prion protein (PrP(C)) to its infectious scrapie isoform (PrP(Sc)), which causes neurodegenerative diseases in many mammals. These two forms have identical sequences and are conformational isomers, with heightened formation of beta-sheet structure in the scrapie form. Conversion can be triggered by lowering the pH, but thus far it has been impossible to characterize the conformational change at high resolution using experimental methods. Therefore, to investigate the effect of acidic pH on PrP conformation, we have performed molecular-dynamics simulations of hamster, human and bovine forms of the prion protein in water at neutral and low pH. In all cases the core of the protein is well maintained at neutral pH. At low pH, however, the protein is more dynamic, and the sheet-like structure increases both by lengthening of the native beta-sheet and by addition of a portion of the N-terminus to widen the sheet by another 2-3 strands.
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Affiliation(s)
- Darwin O V Alonso
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195-7610, USA
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46
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Baskakov IV, Legname G, Baldwin MA, Prusiner SB, Cohen FE. Pathway complexity of prion protein assembly into amyloid. J Biol Chem 2002; 277:21140-8. [PMID: 11912192 DOI: 10.1074/jbc.m111402200] [Citation(s) in RCA: 346] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In vivo under pathological conditions, the normal cellular form of the prion protein, PrP(C) (residues 23-231), misfolds to the pathogenic isoform PrP(Sc), a beta-rich aggregated pathogenic multimer. Proteinase K digestion of PrP(Sc) leads to a proteolytically resistant core, PrP 27-30 (residues 90-231), that can form amyloid fibrils. To study the kinetic pathways of amyloid formation in vitro, we used unglycosylated recombinant PrP corresponding to the proteinase K-resistant core of PrP(Sc) and found that it can adopt two non-native abnormal isoforms, a beta-oligomer and an amyloid fibril. Several lines of kinetic data suggest that the beta-oligomer is not on the pathway to amyloid formation. The preferences for forming either a beta-oligomer or amyloid can be dictated by experimental conditions, with acidic pH similar to that seen in endocytic vesicles favoring the beta-oligomer and neutral pH favoring amyloid. Although both abnormal isoforms have high beta-sheet content and bind 1-anilinonaphthalene-8-sulfonate, they are dissimilar structurally. Multiple pathways of misfolding and the formation of distinct beta-sheet-rich abnormal isoforms may explain the difficulties in refolding PrP(Sc) in vitro, the need for a PrP(Sc) template, and the significant variation in disease presentation and neuropathology.
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Affiliation(s)
- Ilia V Baskakov
- Institute for Neurodegenerative Diseases, University of California, San Francisco, California 94143, USA
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47
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Ball HL, King DS, Cohen FE, Prusiner SB, Baldwin MA. Engineering the prion protein using chemical synthesis. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2001; 58:357-74. [PMID: 11892845 DOI: 10.1034/j.1399-3011.2001.00943.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In recent years, the technology of solid-phase peptide synthesis (SPPS) has improved to the extent that chemical synthesis of small proteins may be a viable complementary strategy to recombinant expression. We have prepared several modified and wild-type prion protein (PrP) polypeptides, of up to 112 residues, that demonstrate the flexibility of a chemical approach to protein synthesis. The principal event in prion disease is the conformational change of the normal, alpha-helical cellular protein (PrPc) into a beta-sheet-rich pathogenic isoform (PrP(Sc)). The ability to form PrP(Sc) in transgenic mice is retained by a 106 residue 'mini-prion' (PrP106), with the deletions 23-88 and 141-176. Synthetic PrP106 (sPrP106) and a His-tagged analog (sPrP106HT) have been prepared successfully using a highly optimized Fmoc chemical methodology involving DCC/HOBt activation and an efficient capping procedure with N-(2-chlorobenzyloxycarbonyloxy) succinimide. A single reversed-phase purification step gave homogeneous protein, in excellent yield. With respect to its conformational and aggregational properties and its response to proteinase digestion, sPrP106 was indistinguishable from its recombinant analog (rPrP106). Certain sequences that proved to be more difficult to synthesize using the Fmoc approach, such as bovine (Bo) PrP(90-200), were successfully prepared using a combination of the highly activated coupling reagent HATU and t-Boc chemistry. To mimic the glycosylphosphatidyl inositol (GPI) anchor and target sPrP to cholesterol-rich domains on the cell surface, where the conversion of PrPc is believed to occur, a lipophilic group or biotin, was added to an orthogonally side-chain-protected Lys residue at the C-terminus of sPrP sequences. These groups enabled sPrP to be immobilized on either the cell surface or a streptavidin-coated ELISA plate, respectively, in an orientation analogous to that of membrane-bound, GPI-anchored PrPc. The chemical manipulation of such biologically relevant forms of PrP by the introduction of point mutations or groups that mimic post-translational modifications should enhance our understanding of the processes that cause prion diseases and may lead to the chemical synthesis of an infectious agent.
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Affiliation(s)
- H L Ball
- Institute for Neurodegenerative Diseases and Department of Neurology, University of California at San Francisco, 94143-0518, USA.
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Zhao H, Chen MH, Shen ZM, Kahn PC, Lipke PN. Environmentally induced reversible conformational switching in the yeast cell adhesion protein alpha-agglutinin. Protein Sci 2001; 10:1113-23. [PMID: 11369849 PMCID: PMC2374011 DOI: 10.1110/ps.41701] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
The yeast cell adhesion protein alpha-agglutinin is expressed on the surface of a free-living organism and is subjected to a variety of environmental conditions. Circular dichroism (CD) spectroscopy shows that the binding region of alpha-agglutinin has a beta-sheet-rich structure, with only approximately 2% alpha-helix under native conditions (15-40 degrees C at pH 5.5). This region is predicted to fold into three immunoglobulin-like domains, and models are consistent with the CD spectra as well as with peptide mapping and site-specific mutagenesis. However, secondary structure prediction algorithms show that segments comprising approximately 17% of the residues have high alpha-helical and low beta-sheet potential. Two model peptides of such segments had helical tendencies, and one of these peptides showed pH-dependent conformational switching. Similarly, CD spectroscopy of the binding region of alpha-agglutinin showed reversible conversion from beta-rich to mixed alpha/beta structure at elevated temperatures or when the pH was changed. The reversibility of these changes implied that there is a small energy difference between the all-beta and the alpha/beta states. Similar changes followed cleavage of peptide or disulfide bonds. Together, these observations imply that short sequences of high helical propensity are constrained to a beta-rich state by covalent and local charge interactions under native conditions, but form helices under non-native conditions.
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Affiliation(s)
- H Zhao
- Department of Biological Sciences and the Institute for Biomolecular Structure and Function, Hunter College of the City University of New York, New York 10021,USA
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49
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Derreumaux P. Evidence that the 127-164 region of prion proteins has two equi-energetic conformations with beta or alpha features. Biophys J 2001; 81:1657-65. [PMID: 11509378 PMCID: PMC1301643 DOI: 10.1016/s0006-3495(01)75819-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Prion proteins cause neurodegenerative illnesses in humans and animals. The diseases are associated with a topological change from a predominantly alpha (PrP(C)) to beta-sheet (PrP(Sc)) structure. Many studies have focused on the minimum sequence requirements and key events for developing or transmitting disease. Here, we report on the application of molecular modeling studies to predict the lowest-energy conformations for five fragments in solution at pH 7. We show that PrP(143-158) adopts a helix, the model PrP(106-126), PrP(142-167), and PrP(143-178) peptides have a clear preference for a variety of beta-sheet structures, whereas PrP(127-164) has two iso-energetic conformations with all beta or alphabeta native-like structures. Such a finding for PrP(127-164), which explains a large body of experimental data, including the location of all mutations causing prion diseases, may have important implications for triggering or propagating the topological change.
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Affiliation(s)
- P Derreumaux
- Information Génétique et Structurale, CNRS-UMR 1889, 13402 Marseille, France.
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Baskakov IV, Legname G, Prusiner SB, Cohen FE. Folding of prion protein to its native alpha-helical conformation is under kinetic control. J Biol Chem 2001; 276:19687-90. [PMID: 11306559 DOI: 10.1074/jbc.c100180200] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The recombinant mouse prion protein (MoPrP) can be folded either to a monomeric alpha-helical or oligomeric beta-sheet-rich isoform. By using circular dichroism spectroscopy and size-exclusion chromatography, we show that the beta-rich isoform of MoPrP is thermodynamically more stable than the native alpha-helical isoform. The conformational transition from the alpha-helical to beta-rich isoform is separated by a large energetic barrier that is associated with unfolding and with a higher order kinetic process related to oligomerization. Under partially denaturing acidic conditions, MoPrP avoids the kinetic trap posed by the alpha-helical isoform and folds directly to the thermodynamically more stable beta-rich isoform. Our data demonstrate that the folding of the prion protein to its native alpha-helical monomeric conformation is under kinetic control.
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Affiliation(s)
- I V Baskakov
- Institute for Neurodegenerative Diseases, Department of Neurology, University of California, San Francisco, California 94143, USA
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