1
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Dasari AKR, Coats MF, Ali AB, Lim KH. Identification of the interfacial regions in misfolded transthyretin oligomers. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2024; 1872:141027. [PMID: 38796131 PMCID: PMC11283945 DOI: 10.1016/j.bbapap.2024.141027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/14/2024] [Accepted: 05/22/2024] [Indexed: 05/28/2024]
Abstract
Misfolding and aggregation of transthyretin (TTR) is associated with numerous ATTR amyloidosis. TTR aggregates extracted from ATTR patients consist of not only full-length TTR, but also N-terminally truncated TTR fragments that can be produced by proteolytic cleavage, suggesting the presence of multiple misfolding pathways. Here, we report mechanistic studies of an early stage of TTR aggregation to probe the oligomerization process for the full-length as well as N-terminally truncated TTR. Our kinetic analyses using size exclusion chromatography revealed that amyloidogenic monomers dissociated from wild-type (WT) as well as pathogenic variants (V30M and L55P) form misfolded dimers, which self-assemble into oligomers, precursors of fibril formation. Dimeric interfaces in the full-length misfolded oligomers were investigated by examining the effect of single-point mutations on the two β-strands (F and H). The single-point mutations on the two β-strands (E92P on strand F and T119W on strand H) inhibited the dimerization of misfolded monomers, while the TTR variants can still form native dimers through the same F and H strands. These results suggest that the two strands are involved in intermolecular associations for both native and misfolded dimers, but detailed intermolecular interactions are different in the two forms of dimers. In the presence of a proteolytic enzyme, TTR aggregation is greatly accelerated. The two mutations on the two β-strands, however, inhibited TTR aggregation even in the presence of a proteolytic enzyme, trypsin. These results suggest that the two β-strands (F and H) play a critical role in aggregation of the N-terminally truncated TTR as well.
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Affiliation(s)
- Anvesh K R Dasari
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | - Matthew F Coats
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | | | - Kwang Hun Lim
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA.
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2
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Chatterjee S, Salimi A, Lee JY. Histidine tautomerism-mediated transthyretin amyloidogenesis: A molecular insight. Arch Biochem Biophys 2023; 742:109618. [PMID: 37172673 DOI: 10.1016/j.abb.2023.109618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 04/26/2023] [Accepted: 05/01/2023] [Indexed: 05/15/2023]
Abstract
Characterization of the conformational alterations involved in monomer misfolding is essential for elucidating the molecular basis of the initial stage of protein accumulation. Here, we report the first structural analyses of transthyretin (TTR) (26-57) fragments with two histidine tautomeric states (δ; Nδ1H and ε; Nε2H) using replica-exchange molecular dynamics (REMD) simulations. Explaining the organizational properties and misfolding procedure is challenging because the δ and ε configurations can occur in the free neutral state. REMD revealed that β-sheet generation is favored for the δδ (16.8%) and εδ (6.7%) tautomeric isomers, showing frequent main-chain contacts between the stable regions near the head (N-terminus) and central (middle) part compared to the εε (4.8%) and δε (2.8%) isomers. The presence of smaller and wider local energy minima may be related to the structural stability and toxicity of δδ/εδ and εε/δε. Histidines31 and 56 were the parts of regular (such as β-strand) and nonregular (such as coil) secondary structures within the highly toxic TTR isomer. For TTR amyloidosis, focusing on hazardous isomeric forms with high sheet contents may be a potent treatment strategy. Overall, our findings support the tautomerism concept and aid in our comprehension of the basic tautomeric actions of neutral histidine throughout the misfolding process.
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Affiliation(s)
- Sompriya Chatterjee
- Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, South Korea
| | - Abbas Salimi
- Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, South Korea
| | - Jin Yong Lee
- Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, South Korea.
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3
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Duan G, Li Y, Ye M, Liu H, Wang N, Luo S. The Regulatory Mechanism of Transthyretin Irreversible Aggregation through Liquid-to-Solid Phase Transition. Int J Mol Sci 2023; 24:ijms24043729. [PMID: 36835140 PMCID: PMC9960511 DOI: 10.3390/ijms24043729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 02/17/2023] Open
Abstract
Transthyretin (TTR) aggregation and amyloid formation are associated with several ATTR diseases, such as senile systemic amyloidosis (SSA) and familial amyloid polyneuropathy (FAP). However, the mechanism that triggers the initial pathologic aggregation process of TTR remains largely elusive. Lately, increasing evidence has suggested that many proteins associated with neurodegenerative diseases undergo liquid-liquid phase separation (LLPS) and subsequent liquid-to-solid phase transition before the formation of amyloid fibrils. Here, we demonstrate that electrostatic interactions mediate LLPS of TTR, followed by a liquid-solid phase transition, and eventually the formation of amyloid fibrils under a mildly acidic pH in vitro. Furthermore, pathogenic mutations (V30M, R34T, and K35T) of TTR and heparin promote the process of phase transition and facilitate the formation of fibrillar aggregates. In addition, S-cysteinylation, which is a kind of post-translational modification of TTR, reduces the kinetic stability of TTR and increases the propensity for aggregation, while another modification, S-sulfonation, stabilizes the TTR tetramer and reduces the aggregation rate. Once TTR was S-cysteinylated or S-sulfonated, they dramatically underwent the process of phase transition, providing a foundation for post-translational modifications that could modulate TTR LLPS in the context of pathological interactions. These novel findings reveal molecular insights into the mechanism of TTR from initial LLPS and subsequent liquid-to-solid phase transition to amyloid fibrils, providing a new dimension for ATTR therapy.
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4
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Dasari AKR, Yi S, Coats MF, Wi S, Lim KH. Toxic Misfolded Transthyretin Oligomers with Different Molecular Conformations Formed through Distinct Oligomerization Pathways. Biochemistry 2022; 61:2358-2365. [PMID: 36219173 PMCID: PMC9665167 DOI: 10.1021/acs.biochem.2c00390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein aggregation is initiated by structural changes from native polypeptides to cytotoxic oligomers, which form cross-β structured amyloid. Identification and characterization of oligomeric intermediates are critically important for understanding not only the molecular mechanism of aggregation but also the cytotoxic nature of amyloid oligomers. Preparation of misfolded oligomers for structural characterization is, however, challenging because of their transient, heterogeneous nature. Here, we report two distinct misfolded transthyretin (TTR) oligomers formed through different oligomerization pathways. A pathogenic TTR variant with a strong aggregation propensity (L55P) was used to prepare misfolded oligomers at physiological pH. Our mechanistic studies showed that the full-length TTR initially forms small oligomers, which self-assemble into short protofibrils at later stages. Enzymatic cleavage of the CD loop was also used to induce the formation of N-terminally truncated oligomers, which was detected in ex vivo cardiac TTR aggregates extracted from the tissues of patients. Structural characterization of the oligomers using solid-state nuclear magnetic resonance and circular dichroism revealed that the two TTR misfolded oligomers have distinct molecular conformations. In addition, the proteolytically cleaved TTR oligomers exhibit a higher surface hydrophobicity, suggesting the presence of distinct oligomerization pathways for TTR oligomer formation. Cytotoxicity assays also revealed that the cytotoxicity of cleaved oligomers is stronger than that of the full-length TTR oligomers, indicating that hydrophobicity might be an important property of toxic oligomers. These comparative biophysical analyses suggest that the toxic cleaved TTR oligomers formed through a different misfoling pathway may adopt distinct structural features that produce higher surface hydrophobicity, leading to the stronger cytotoxic activities.
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Affiliation(s)
- Anvesh K. R. Dasari
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | - Sujung Yi
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | - Matthew F. Coats
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | - Sungsool Wi
- Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), 1800 East, Paul Dirac Dr., Tallahassee, FL 32310, USA
| | - Kwang Hun Lim
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
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5
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Arndt T, Jaudzems K, Shilkova O, Francis J, Johansson M, Laity PR, Sahin C, Chatterjee U, Kronqvist N, Barajas-Ledesma E, Kumar R, Chen G, Strömberg R, Abelein A, Langton M, Landreh M, Barth A, Holland C, Johansson J, Rising A. Spidroin N-terminal domain forms amyloid-like fibril based hydrogels and provides a protein immobilization platform. Nat Commun 2022; 13:4695. [PMID: 35970823 PMCID: PMC9378615 DOI: 10.1038/s41467-022-32093-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 07/15/2022] [Indexed: 11/24/2022] Open
Abstract
Recombinant spider silk proteins (spidroins) have multiple potential applications in development of novel biomaterials, but their multimodal and aggregation-prone nature have complicated production and straightforward applications. Here, we report that recombinant miniature spidroins, and importantly also the N-terminal domain (NT) on its own, rapidly form self-supporting and transparent hydrogels at 37 °C. The gelation is caused by NT α-helix to β-sheet conversion and formation of amyloid-like fibrils, and fusion proteins composed of NT and green fluorescent protein or purine nucleoside phosphorylase form hydrogels with intact functions of the fusion moieties. Our findings demonstrate that recombinant NT and fusion proteins give high expression yields and bestow attractive properties to hydrogels, e.g., transparency, cross-linker free gelation and straightforward immobilization of active proteins at high density. Recombinant spider silks are of interest but the multimodal and aggregation-prone nature of them is a limitation. Here, the authors report on a miniature spidroin based on the N-terminal domain which forms a hydrogel at 37 °C which allows for ease of production and fusion protein modification to generate functional biomaterials.
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Affiliation(s)
- Tina Arndt
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Kristaps Jaudzems
- Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, LV-1006, Latvia
| | - Olga Shilkova
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Juanita Francis
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Mathias Johansson
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, 750 07, Sweden, Box 7015
| | - Peter R Laity
- Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
| | - Cagla Sahin
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solnavägen 9, 171 65, Solna, Sweden
| | - Urmimala Chatterjee
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Nina Kronqvist
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Edgar Barajas-Ledesma
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solnavägen 9, 171 65, Solna, Sweden
| | - Rakesh Kumar
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Gefei Chen
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Roger Strömberg
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Axel Abelein
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Maud Langton
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, 750 07, Sweden, Box 7015
| | - Michael Landreh
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solnavägen 9, 171 65, Solna, Sweden
| | - Andreas Barth
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, 10691, Stockholm, Sweden
| | - Chris Holland
- Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
| | - Jan Johansson
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden
| | - Anna Rising
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Blickagången 16, Huddinge, 141 52, Sweden. .,Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, 750 07, Sweden.
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6
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Schaefer A, Naser D, Siebeneichler B, Tarasca MV, Meiering EM. Methodological advances and strategies for high resolution structure determination of cellular protein aggregates. J Biol Chem 2022; 298:102197. [PMID: 35760099 PMCID: PMC9396402 DOI: 10.1016/j.jbc.2022.102197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 01/14/2023] Open
Abstract
Aggregation of proteins is at the nexus of molecular processes crucial to aging, disease, and employing proteins for biotechnology and medical applications. There has been much recent progress in determining the structural features of protein aggregates that form in cells; yet, owing to prevalent heterogeneity in aggregation, many aspects remain obscure and often experimentally intractable to define. Here we review recent results of structural studies for cell-derived aggregates of normally globular proteins, with a focus on high resolution methods for their analysis and prediction. Complementary results obtained by solid-state NMR spectroscopy, Fourier transform infrared (FTIR) spectroscopy and microspectroscopy, cryo-electron microscopy, and amide hydrogen/deuterium exchange measured by NMR and mass spectrometry (MS), applied to bacterial inclusion bodies and disease inclusions, are uncovering novel information on in-cell aggregation patterns as well as great diversity in the structural features of useful and aberrant protein aggregates. Using these advances as a guide, this review aims to advise the reader on which combination of approaches may be the most appropriate to apply to their unique system.
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Affiliation(s)
- Anna Schaefer
- Department of Chemistry, University of Waterloo Waterloo ON Canada
| | - Dalia Naser
- Department of Chemistry, University of Waterloo Waterloo ON Canada
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7
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Sun X, Ferguson JA, Dyson HJ, Wright PE. A transthyretin monomer intermediate undergoes local unfolding and transient interaction with oligomers in a kinetically concerted aggregation pathway. J Biol Chem 2022; 298:102162. [PMID: 35724960 PMCID: PMC9293765 DOI: 10.1016/j.jbc.2022.102162] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/13/2022] [Accepted: 06/15/2022] [Indexed: 11/15/2022] Open
Abstract
Transthyretin (TTR) amyloidosis is associated with tissue deposition of TTR aggregates. TTR aggregation is initiated by dissociation of the native tetramer to form a monomeric intermediate, which locally unfolds and assembles into soluble oligomers and higher-order aggregates. However, a detailed mechanistic understanding requires kinetic and structural characterization of the low-population intermediates formed. Here we show that the monomeric intermediate exchanges with an ensemble of oligomers on the millisecond timescale. This transient and reversible exchange causes broadening of the 19F resonance of a trifluoromethyl probe coupled to the monomeric intermediate at S85C. We show the 19F linewidth and R2 relaxation rate increase in a linear manner with increasing concentration of the oligomer. Furthermore, introduction of 19F probes at additional TTR sites yielded distinct 19F chemical shifts for the TTR tetramer and monomer when the trifluoromethyl probe was attached at S100C, located near the same subunit interface as S85C, but not with probes attached at S46C or E63C, which are distant from any interfaces. The 19F probe at E63C shows that part of the DE loop, which is solvent-accessible in the tetramer, becomes more buried in the NMR-visible oligomers. Finally, using backbone amides as probes, we show that parts of the EF helix and H strand become highly flexible in the otherwise structured monomeric intermediate at acidic pH. We further find that TTR aggregation can be reversed by increasing pH. Taken together, this work provides insights into location-dependent conformational changes in the reversible early steps of a kinetically-concerted TTR aggregation pathway.
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Affiliation(s)
- Xun Sun
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
| | - James A Ferguson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
| | - H Jane Dyson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, California, USA.
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8
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Yang W, Kim BS, Muniyappan S, Lee YH, Kim JH, Yu W. Aggregation-Prone Structural Ensembles of Transthyretin Collected With Regression Analysis for NMR Chemical Shift. Front Mol Biosci 2021; 8:766830. [PMID: 34746240 PMCID: PMC8568061 DOI: 10.3389/fmolb.2021.766830] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/05/2021] [Indexed: 11/26/2022] Open
Abstract
Monomer dissociation and subsequent misfolding of the transthyretin (TTR) is one of the most critical causative factors of TTR amyloidosis. TTR amyloidosis causes several human diseases, such as senile systemic amyloidosis and familial amyloid cardiomyopathy/polyneuropathy; therefore, it is important to understand the molecular details of the structural deformation and aggregation mechanisms of TTR. However, such molecular characteristics are still elusive because of the complicated structural heterogeneity of TTR and its highly sensitive nature to various environmental factors. Several nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) studies of TTR variants have recently reported evidence of transient aggregation-prone structural states of TTR. According to these studies, the stability of the DAGH β-sheet, one of the two main β-sheets in TTR, is a crucial determinant of the TTR amyloidosis mechanism. In addition, its conformational perturbation and possible involvement of nearby structural motifs facilitates TTR aggregation. This study proposes aggregation-prone structural ensembles of TTR obtained by MD simulation with enhanced sampling and a multiple linear regression approach. This method provides plausible structural models that are composed of ensemble structures consistent with NMR chemical shift data. This study validated the ensemble models with experimental data obtained from circular dichroism (CD) spectroscopy and NMR order parameter analysis. In addition, our results suggest that the structural deformation of the DAGH β-sheet and the AB loop regions may correlate with the manifestation of the aggregation-prone conformational states of TTR. In summary, our method employing MD techniques to extend the structural ensembles from NMR experimental data analysis may provide new opportunities to investigate various transient yet important structural states of amyloidogenic proteins.
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Affiliation(s)
- Wonjin Yang
- Department of Brain and Cognitive Sciences, DGIST, Daegu, South Korea
| | - Beom Soo Kim
- Department of Brain and Cognitive Sciences, DGIST, Daegu, South Korea
| | | | - Young-Ho Lee
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, Ochang, South Korea.,Department of Bio-analytical Science, University of Science and Technology, Daejeon, South Korea.,Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, South Korea.,Research Headquarters, Korea Brain Research Institute, Daegu, South Korea
| | - Jin Hae Kim
- Department of New Biology, DGIST, Daegu, South Korea
| | - Wookyung Yu
- Department of Brain and Cognitive Sciences, DGIST, Daegu, South Korea.,Core Protein Resources Center, DGIST, Daegu, South Korea
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9
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Transthyretin Misfolding, A Fatal Structural Pathogenesis Mechanism. Int J Mol Sci 2021; 22:ijms22094429. [PMID: 33922648 PMCID: PMC8122960 DOI: 10.3390/ijms22094429] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/18/2021] [Accepted: 04/21/2021] [Indexed: 12/11/2022] Open
Abstract
Transthyretin (TTR) is an essential transporter of a thyroid hormone and a holo-retinol binding protein, found abundantly in human plasma and cerebrospinal fluid. In addition, this protein is infamous for its amyloidogenic propensity, causing various amyloidoses in humans, such as senile systemic amyloidosis, familial amyloid polyneuropathy, and familial amyloid cardiomyopathy. It has been known for over two decades that decreased stability of the native tetrameric conformation of TTR is the main cause of these diseases. Yet, mechanistic details on the amyloidogenic transformation of TTR were not clear until recent multidisciplinary investigations on various structural states of TTR. In this review, we discuss recent advancements in the structural understanding of TTR misfolding and amyloidosis processes. Special emphasis has been laid on the observations of novel structural features in various amyloidogenic species of TTR. In addition, proteolysis-induced fragmentation of TTR, a recently proposed mechanism facilitating TTR amyloidosis, has been discussed in light of its structural consequences and relevance to acknowledge the amyloidogenicity of TTR.
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10
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Childers MC, Daggett V. Edge Strand Dissociation and Conformational Changes in Transthyretin under Amyloidogenic Conditions. Biophys J 2020; 119:1995-2009. [PMID: 33091379 DOI: 10.1016/j.bpj.2020.08.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/09/2020] [Accepted: 08/31/2020] [Indexed: 01/18/2023] Open
Abstract
During amyloidogenesis, proteins undergo conformational changes that allow them to aggregate and assemble into insoluble, fibrillar structures. Soluble oligomers that form during this process typically contain 2-24 monomeric subunits and are cytotoxic. Before the formation of these soluble oligomers, monomeric species first adopt aggregation-competent conformations. Knowledge of the structures of these intermediate states is invaluable to the development of molecular strategies to arrest pathological amyloid aggregation. However, the highly dynamic and interconverting nature of amyloidogenic species limits biophysical characterization of their structures during amyloidogenesis. Here, we use molecular dynamics simulations to probe conformations sampled by monomeric transthyretin under amyloidogenic conditions. We show that certain β-strands in transthyretin tend to unfold and sample nonnative conformations and that the edge strands in one β-sheet (the DAGH sheet) are particularly susceptible to conformational changes in the monomeric state. We also find that changes in the tertiary structure of transthyretin can be associated with disruptions to the secondary structure. We evaluated the conformations produced by molecular dynamics by calculating how well molecular-dynamics-derived structures reproduced NMR-derived interatomic distances. Finally, we leverage our computational results to produce experimentally testable hypotheses that may aid experimental explorations of pathological conformations of transthyretin.
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Affiliation(s)
- Matthew C Childers
- Department of Bioengineering, University of Washington, Seattle, Washington.
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, Washington
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11
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Dasari AKR, Hung I, Michael B, Gan Z, Kelly JW, Connors LH, Griffin RG, Lim KH. Structural Characterization of Cardiac Ex Vivo Transthyretin Amyloid: Insight into the Transthyretin Misfolding Pathway In Vivo. Biochemistry 2020; 59:1800-1803. [PMID: 32338497 DOI: 10.1021/acs.biochem.0c00091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Structural characterization of misfolded protein aggregates is essential to understanding the molecular mechanism of protein aggregation associated with various protein misfolding disorders. Here, we report structural analyses of ex vivo transthyretin aggregates extracted from human cardiac tissue. Comparative structural analyses of in vitro and ex vivo transthyretin aggregates using various biophysical techniques revealed that cardiac transthyretin amyloid has structural features similar to those of in vitro transthyretin amyloid. Our solid-state nuclear magnetic resonance studies showed that in vitro amyloid contains extensive nativelike β-sheet structures, while other loop regions including helical structures are disrupted in the amyloid state. These results suggest that transthyretin undergoes a common misfolding and aggregation transition to nativelike aggregation-prone monomers that self-assemble into amyloid precipitates in vitro and in vivo.
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Affiliation(s)
- Anvesh K R Dasari
- Department of Chemistry, East Carolina University, Greenville, North Carolina 27858, United States
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Brian Michael
- Department of Chemistry, Massachuseets Institute of Technology, NW14-3220, 170 Albany Street, Cambridge, Massachusetts 02139-4703, United States
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Jeffery W Kelly
- Department of Molecular and Experimental Medicine, Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Lawreen H Connors
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, 72 East Concord Street, Boston, Massachusetts 02118, United States
| | - Robert G Griffin
- Department of Chemistry, Massachuseets Institute of Technology, NW14-3220, 170 Albany Street, Cambridge, Massachusetts 02139-4703, United States
| | - Kwang Hun Lim
- Department of Chemistry, East Carolina University, Greenville, North Carolina 27858, United States
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12
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Cryo-EM structure of a transthyretin-derived amyloid fibril from a patient with hereditary ATTR amyloidosis. Nat Commun 2019; 10:5008. [PMID: 31676763 PMCID: PMC6825171 DOI: 10.1038/s41467-019-13038-z] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 10/17/2019] [Indexed: 12/21/2022] Open
Abstract
ATTR amyloidosis is one of the worldwide most abundant forms of systemic amyloidosis. The disease is caused by the misfolding of transthyretin protein and the formation of amyloid deposits at different sites within the body. Here, we present a 2.97 Å cryo electron microscopy structure of a fibril purified from the tissue of a patient with hereditary Val30Met ATTR amyloidosis. The fibril consists of a single protofilament that is formed from an N-terminal and a C-terminal fragment of transthyretin. Our structure provides insights into the mechanism of misfolding and implies the formation of an early fibril state from unfolded transthyretin molecules, which upon proteolysis converts into mature ATTR amyloid fibrils. Systemic amyloidosis of the ATTR is one of the most abundant forms of systemic amyloidosis and caused by misfolding of the circulating blood protein transthyretin (TTR). Here the authors present the cryo-EM structure of patient-derived Val30Met ATTR amyloid fibrils which reveals that the protofilament consists of an N-terminal and a C-terminal TTR fragment and discuss implications for the mechanism of misfolding.
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13
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Childers MC, Daggett V. Drivers of α-Sheet Formation in Transthyretin under Amyloidogenic Conditions. Biochemistry 2019; 58:4408-4423. [PMID: 31609590 DOI: 10.1021/acs.biochem.9b00769] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Amyloid diseases make up a set of fatal disorders in which proteins aggregate to form fibrils that deposit in tissues throughout the body. Amyloid-associated diseases are challenging to study because amyloid formation occurs on time scales that span several orders of magnitude and involve heterogeneous, interconverting protein conformations. The development of more effective technologies to diagnose and treat amyloid disease requires both a map of the conformations sampled during amyloidogenesis and an understanding of the molecular mechanisms that drive this process. In prior molecular dynamics simulations of amyloid proteins, we observed the formation of a nonstandard type of secondary structure, called α-sheet, that we proposed is associated with the pathogenic conformers in amyloid disease, the soluble oligomers. However, the detailed molecular interactions that drive the conversion to α-sheet remain elusive. Here we use molecular dynamics simulations to interrogate a critical event in transthyretin aggregation, the formation of aggregation-competent, monomeric species. We show that conformational changes in one of the two β-sheets in transthyretin enable solvent molecules and polar side chains to form electrostatic interactions with main-chain peptide groups to facilitate and modulate conversion to α-sheet secondary structure. Our results shed light on the early conformational changes that drive transthyretin toward the α-sheet structure associated with toxicity. Delineation of the molecular events that lead to aggregation at atomic resolution can aid strategies to target the early, critical toxic soluble oligomers.
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Affiliation(s)
- Matthew Carter Childers
- Department of Bioengineering , University of Washington , Seattle , Washington 98195-5013 , United States
| | - Valerie Daggett
- Department of Bioengineering , University of Washington , Seattle , Washington 98195-5013 , United States
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14
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Ruggeri FS, Šneideris T, Vendruscolo M, Knowles TPJ. Atomic force microscopy for single molecule characterisation of protein aggregation. Arch Biochem Biophys 2019; 664:134-148. [PMID: 30742801 PMCID: PMC6420408 DOI: 10.1016/j.abb.2019.02.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/03/2019] [Accepted: 02/05/2019] [Indexed: 12/22/2022]
Abstract
The development of atomic force microscopy (AFM) has opened up a wide range of novel opportunities in nanoscience and new modalities of observation in complex biological systems. AFM imaging has been widely employed to resolve the complex and heterogeneous conformational states involved in protein aggregation at the single molecule scale and shed light onto the molecular basis of a variety of human pathologies, including neurodegenerative disorders. The study of individual macromolecules at nanoscale, however, remains challenging, especially when fully quantitative information is required. In this review, we first discuss the principles of AFM with a special emphasis on the fundamental factors defining its sensitivity and accuracy. We then review the fundamental parameters and approaches to work at the limit of AFM resolution in order to perform single molecule statistical analysis of biomolecules and nanoscale protein aggregates. This single molecule statistical approach has proved to be powerful to unravel the molecular and hierarchical assembly of the misfolded species present transiently during protein aggregation, to visualise their dynamics at the nanoscale, as well to study the structural properties of amyloid-inspired functional nanomaterials.
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Affiliation(s)
- Francesco Simone Ruggeri
- Centre for Misfolding Disease, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom.
| | - Tomas Šneideris
- Centre for Misfolding Disease, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom; Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Michele Vendruscolo
- Centre for Misfolding Disease, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom
| | - Tuomas P J Knowles
- Centre for Misfolding Disease, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom; Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, United Kingdom.
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15
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Dasari AKR, Hughes RM, Wi S, Hung I, Gan Z, Kelly JW, Lim KH. Transthyretin Aggregation Pathway toward the Formation of Distinct Cytotoxic Oligomers. Sci Rep 2019; 9:33. [PMID: 30631096 PMCID: PMC6328637 DOI: 10.1038/s41598-018-37230-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/30/2018] [Indexed: 01/12/2023] Open
Abstract
Characterization of small oligomers formed at an early stage of amyloid formation is critical to understanding molecular mechanism of pathogenic aggregation process. Here we identified and characterized cytotoxic oligomeric intermediates populated during transthyretin (TTR) aggregation process. Under the amyloid-forming conditions, TTR initially forms a dimer through interactions between outer strands. The dimers are then associated to form a hexamer with a spherical shape, which serves as a building block to self-assemble into cytotoxic oligomers. Notably, wild-type (WT) TTR tends to form linear oligomers, while a TTR variant (G53A) prefers forming annular oligomers with pore-like structures. Structural analyses of the amyloidogenic intermediates using circular dichroism (CD) and solid-state NMR reveal that the dimer and oligomers have a significant degree of native-like β-sheet structures (35–38%), but with more disordered regions (~60%) than those of native TTR. The TTR variant oligomers are also less structured than WT oligomers. The partially folded nature of the oligomeric intermediates might be a common structural property of cytotoxic oligomers. The higher flexibility of the dimer and oligomers may also compensate for the entropic loss due to the oligomerization of the monomers.
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Affiliation(s)
- Anvesh K R Dasari
- Department of Chemistry, East Carolina University, Greenville, NC, 27858, USA
| | - Robert M Hughes
- Department of Chemistry, East Carolina University, Greenville, NC, 27858, USA
| | - Sungsool Wi
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), 1800 East, Paul Dirac Dr., Tallahassee, FL, 32310, USA
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), 1800 East, Paul Dirac Dr., Tallahassee, FL, 32310, USA
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), 1800 East, Paul Dirac Dr., Tallahassee, FL, 32310, USA
| | - Jeffrey W Kelly
- Department of Molecular and Experimental Medicine, the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Kwang Hun Lim
- Department of Chemistry, East Carolina University, Greenville, NC, 27858, USA.
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16
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Wilson CJ, Bommarius AS, Champion JA, Chernoff YO, Lynn DG, Paravastu AK, Liang C, Hsieh MC, Heemstra JM. Biomolecular Assemblies: Moving from Observation to Predictive Design. Chem Rev 2018; 118:11519-11574. [PMID: 30281290 PMCID: PMC6650774 DOI: 10.1021/acs.chemrev.8b00038] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Biomolecular assembly is a key driving force in nearly all life processes, providing structure, information storage, and communication within cells and at the whole organism level. These assembly processes rely on precise interactions between functional groups on nucleic acids, proteins, carbohydrates, and small molecules, and can be fine-tuned to span a range of time, length, and complexity scales. Recognizing the power of these motifs, researchers have sought to emulate and engineer biomolecular assemblies in the laboratory, with goals ranging from modulating cellular function to the creation of new polymeric materials. In most cases, engineering efforts are inspired or informed by understanding the structure and properties of naturally occurring assemblies, which has in turn fueled the development of predictive models that enable computational design of novel assemblies. This Review will focus on selected examples of protein assemblies, highlighting the story arc from initial discovery of an assembly, through initial engineering attempts, toward the ultimate goal of predictive design. The aim of this Review is to highlight areas where significant progress has been made, as well as to outline remaining challenges, as solving these challenges will be the key that unlocks the full power of biomolecules for advances in technology and medicine.
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Affiliation(s)
- Corey J. Wilson
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Andreas S. Bommarius
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Julie A. Champion
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Yury O. Chernoff
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Laboratory of Amyloid Biology & Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg 199034, Russia
| | - David G. Lynn
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Anant K. Paravastu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Chen Liang
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Ming-Chien Hsieh
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Jennifer M. Heemstra
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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17
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Dasari AKR, Hung I, Gan Z, Lim KH. Two distinct aggregation pathways in transthyretin misfolding and amyloid formation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1867:344-349. [PMID: 30366153 DOI: 10.1016/j.bbapap.2018.10.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/17/2018] [Accepted: 10/22/2018] [Indexed: 01/17/2023]
Abstract
Misfolding and amyloid formation of transthyretin (TTR) is implicated in numerous degenerative diseases. TTR misfolding is greatly accelerated under acidic conditions, and thus most of the mechanistic studies of TTR amyloid formation have been conducted at various acidic pH values (2-5). In this study, we report the effect of pH on TTR misfolding pathways and amyloid structures. Our combined solution and solid-state NMR studies revealed that TTR amyloid formation can proceed via at least two distinct misfolding pathways depending on the acidic conditions. Under mildly acidic conditions (pH 4.4), tetrameric native TTR appears to dissociate to monomers that maintain most of the native-like β-sheet structures. The amyloidogenic protein undergoes a conformational transition to largely unfolded states at more acidic conditions (pH 2.4), leading to amyloid with distinct molecular structures. Aggregation kinetics is also highly dependent upon the acidic conditions. TTR quickly forms moderately ordered amyloids at pH 4.4, while the aggregation kinetics is dramatically reduced at a lower pH of 2.4. The effect of the pathogenic mutations on aggregation kinetics is also markedly different under the two different acidic conditions. Pathogenic TTR variants (V30M and L55P) aggregate more aggressively than WT TTR at pH 4.4. In contrast, the single-point mutations do not affect the aggregation kinetics at the more acidic condition of pH 2.4. Given that the pathogenic mutations lead to more aggressive forms of TTR amyloidoses, the mildly acidic condition might be more suitable for mechanistic studies of TTR misfolding and aggregation.
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Affiliation(s)
- Anvesh K R Dasari
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), 1800 East, Paul Dirac Dr., Tallahassee, FL 32310, USA
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), 1800 East, Paul Dirac Dr., Tallahassee, FL 32310, USA
| | - Kwang Hun Lim
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA.
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18
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Leach BI, Zhang X, Kelly JW, Dyson HJ, Wright PE. NMR Measurements Reveal the Structural Basis of Transthyretin Destabilization by Pathogenic Mutations. Biochemistry 2018; 57:4421-4430. [PMID: 29972637 PMCID: PMC6067956 DOI: 10.1021/acs.biochem.8b00642] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Inherited mutations of transthyretin (TTR) destabilize its structure, leading to aggregation and familial amyloid disease. Although numerous crystal structures of wild-type (WT) and mutant TTRs have been determined, they have failed to yield a comprehensive structural explanation for destabilization by pathogenic mutations. To identify structural and dynamic variations that are not readily observed in the crystal structures, we used NMR to study WT TTR and three kinetically and/or thermodynamically destabilized pathogenic variants (V30M, L55P, and V122I). Sequence-corrected chemical shifts reveal important structural differences between WT and mutant TTR. The L55P mutation linked to aggressive early onset cardiomyopathy and polyneuropathy induces substantial structural perturbations in both the DAGH and CBEF β-sheets, whereas the V30M polyneuropathy-linked substitution perturbs primarily the CBEF sheet. In both variants, the structural perturbations propagate across the entire width of the β-sheets from the site of mutation. Structural changes caused by the V122I cardiomyopathy-associated mutation are restricted to the immediate vicinity of the mutation site, directly perturbing the subunit interfaces. NMR relaxation dispersion measurements show that WT TTR and the three pathogenic variants undergo millisecond time scale conformational fluctuations to populate a common excited state with an altered structure in the subunit interfaces. The excited state is most highly populated in L55P. The combined application of chemical shift analysis and relaxation dispersion to these pathogenic variants reveals differences in ground state structure and in the population of a transient excited state that potentially facilitates tetramer dissociation, providing new insights into the molecular mechanism by which mutations promote TTR amyloidosis.
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Affiliation(s)
- Benjamin I. Leach
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037
| | - Xin Zhang
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania16802
| | - Jeffery W. Kelly
- Department of Chemistry and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037
| | - H. Jane Dyson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037
| | - Peter E. Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037
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19
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Kinetic analysis of the multistep aggregation pathway of human transthyretin. Proc Natl Acad Sci U S A 2018; 115:E6201-E6208. [PMID: 29915031 DOI: 10.1073/pnas.1807024115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Aggregation of transthyretin (TTR) is the causative agent for TTR cardiomyopathy and polyneuropathy amyloidoses. Aggregation is initiated by dissociation of the TTR tetramer into a monomeric intermediate, which self-assembles into amyloid. The coupled multiple-step equilibria and low-concentration, aggregation-prone intermediates are challenging to probe using conventional assays. We report a 19F-NMR assay that leverages a highly sensitive trifluoroacetyl probe at a strategic site that gives distinct 19F chemical shifts for the TTR tetramer and monomeric intermediate and enables direct quantification of their populations during the aggregation process. Integration of real-time 19F-NMR and turbidity measurements as a function of temperature allows kinetic and mechanistic dissection of the aggregation pathway of both wild-type and mutant TTR. At physiological temperature, the monomeric intermediate formed by wild-type TTR under mildly acidic conditions rapidly aggregates into species that are invisible to NMR, leading to loss of the NMR signal at the same rate as the turbidity increase. Lower temperature accelerates tetramer dissociation and decelerates monomer tetramerization and oligomerization via reduced hydrophobic interactions associated with packing of a phenylalanine (F87) into a neighboring protomer. As a result, the intermediate accumulates to a higher level, and formation of higher-order aggregates is delayed. Application of this assay to pathogenic (V30M, L55P, and V122I) and protective (T119M) mutants revealed significant differences in behavior. A monomeric intermediate was observed only for V122I: aggregation of V30M and L55P proceeds without an observable monomeric intermediate, whereas the protective mutant T119M remains resistant to tetramer dissociation and aggregation.
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20
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Higman VA. Solid-state MAS NMR resonance assignment methods for proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 106-107:37-65. [PMID: 31047601 DOI: 10.1016/j.pnmrs.2018.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/19/2018] [Accepted: 04/24/2018] [Indexed: 06/09/2023]
Abstract
The prerequisite to structural or functional studies of proteins by NMR is generally the assignment of resonances. Since the first assignment of proteins by solid-state MAS NMR was conducted almost two decades ago, a wide variety of different pulse sequences and methods have been proposed and continue to be developed. Traditionally, a variety of 2D and 3D 13C-detected experiments have been used for the assignment of backbone and side-chain 13C and 15N resonances. These methods have found widespread use across the field. But as the hardware has changed and higher spinning frequencies and magnetic fields are becoming available, the ability to use direct proton detection is opening up a new set of assignment methods based on triple-resonance experiments. This review describes solid-state MAS NMR assignment methods using carbon detection and proton detection at different deuteration levels. The use of different isotopic labelling schemes as an aid to assignment in difficult cases is discussed as well as the increasing number of software packages that support manual and automated resonance assignment.
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Affiliation(s)
- Victoria A Higman
- Department of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TU, UK.
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21
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Galzitskaya OV, Galushko EI, Selivanova OM. Studies of the Process of Amyloid Formation by Aβ Peptide. BIOCHEMISTRY (MOSCOW) 2018; 83:S62-S80. [PMID: 29544432 DOI: 10.1134/s0006297918140079] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Studies of the process of amyloid formation by Aβ peptide have been topical due to the critical role of this peptide in the pathogenesis of Alzheimer's disease. Many articles devoted to this process are available in the literature; however, none of them gives a detailed description of the mechanism of the process of generation of amyloids. Moreover, there are no reliable data on the influence of modified forms of Aβ peptide on its amyloid formation. To appreciate the role of Aβ aggregation in the pathogenesis of Alzheimer's disease and to develop a strategy for its treatment, it is necessary to have a well-defined description of the molecular mechanism underlying the formation of amyloids as well as the contribution of each intermediate to this process. We are convinced that a combined analysis of theoretical and experimental methods is a way for understanding molecular mechanisms of numerous diseases. Based on our experimental data and molecular modeling, we have constructed a general model of the process of amyloid formation by Aβ peptide. Using the data described in our previous publications, we propose a model of amyloid formation by this peptide that differs from the generally accepted model. Our model can be applied to other proteins and peptides as well. According to this model, the main building unit for the formation of amyloid fibrils is a ring-like oligomer. Upon interaction with each other, ring-like oligomers form long fibrils of different morphology. This mechanism of generation of amyloid fibrils may be common for other proteins and peptides.
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Affiliation(s)
- O V Galzitskaya
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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22
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van der Wel PCA. Insights into protein misfolding and aggregation enabled by solid-state NMR spectroscopy. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 88:1-14. [PMID: 29035839 PMCID: PMC5705391 DOI: 10.1016/j.ssnmr.2017.10.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/03/2017] [Accepted: 10/03/2017] [Indexed: 05/17/2023]
Abstract
The aggregation of proteins and peptides into a variety of insoluble, and often non-native, aggregated states plays a central role in many devastating diseases. Analogous processes undermine the efficacy of polypeptide-based biological pharmaceuticals, but are also being leveraged in the design of biologically inspired self-assembling materials. This Trends article surveys the essential contributions made by recent solid-state NMR (ssNMR) studies to our understanding of the structural features of polypeptide aggregates, and how such findings are informing our thinking about the molecular mechanisms of misfolding and aggregation. A central focus is on disease-related amyloid fibrils and oligomers involved in neurodegenerative diseases such as Alzheimer's, Parkinson's and Huntington's disease. SSNMR-enabled structural and dynamics-based findings are surveyed, along with a number of resulting emerging themes that appear common to different amyloidogenic proteins, such as their compact alternating short-β-strand/β-arc amyloid core architecture. Concepts, methods, future prospects and challenges are discussed.
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Affiliation(s)
- Patrick C A van der Wel
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA.
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23
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Cieplak AS. Protein folding, misfolding and aggregation: The importance of two-electron stabilizing interactions. PLoS One 2017; 12:e0180905. [PMID: 28922400 PMCID: PMC5603215 DOI: 10.1371/journal.pone.0180905] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 06/22/2017] [Indexed: 12/17/2022] Open
Abstract
Proteins associated with neurodegenerative diseases are highly pleiomorphic and may adopt an all-α-helical fold in one environment, assemble into all-β-sheet or collapse into a coil in another, and rapidly polymerize in yet another one via divergent aggregation pathways that yield broad diversity of aggregates’ morphology. A thorough understanding of this behaviour may be necessary to develop a treatment for Alzheimer’s and related disorders. Unfortunately, our present comprehension of folding and misfolding is limited for want of a physicochemical theory of protein secondary and tertiary structure. Here we demonstrate that electronic configuration and hyperconjugation of the peptide amide bonds ought to be taken into account to advance such a theory. To capture the effect of polarization of peptide linkages on conformational and H-bonding propensity of the polypeptide backbone, we introduce a function of shielding tensors of the Cα atoms. Carrying no information about side chain-side chain interactions, this function nonetheless identifies basic features of the secondary and tertiary structure, establishes sequence correlates of the metamorphic and pH-driven equilibria, relates binding affinities and folding rate constants to secondary structure preferences, and manifests common patterns of backbone density distribution in amyloidogenic regions of Alzheimer’s amyloid β and tau, Parkinson’s α-synuclein and prions. Based on those findings, a split-intein like mechanism of molecular recognition is proposed to underlie dimerization of Aβ, tau, αS and PrPC, and divergent pathways for subsequent association of dimers are outlined; a related mechanism is proposed to underlie formation of PrPSc fibrils. The model does account for: (i) structural features of paranuclei, off-pathway oligomers, non-fibrillar aggregates and fibrils; (ii) effects of incubation conditions, point mutations, isoform lengths, small-molecule assembly modulators and chirality of solid-liquid interface on the rate and morphology of aggregation; (iii) fibril-surface catalysis of secondary nucleation; and (iv) self-propagation of infectious strains of mammalian prions.
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Affiliation(s)
- Andrzej Stanisław Cieplak
- Department of Chemistry, Bilkent University, Ankara, Turkey
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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24
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Lim KH, Dasari AKR, Ma R, Hung I, Gan Z, Kelly JW, Fitzgerald MC. Pathogenic Mutations Induce Partial Structural Changes in the Native β-Sheet Structure of Transthyretin and Accelerate Aggregation. Biochemistry 2017; 56:4808-4818. [PMID: 28820582 DOI: 10.1021/acs.biochem.7b00658] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloid formation of natively folded proteins involves global and/or local unfolding of the native state to form aggregation-prone intermediates. Here we report solid-state nuclear magnetic resonance (NMR) structural studies of amyloid derived from wild-type (WT) and more aggressive mutant forms of transthyretin (TTR) to investigate the structural changes associated with effective TTR aggregation. We employed selective 13C labeling schemes to investigate structural features of β-structured core regions in amyloid states of WT and two mutant forms (V30M and L55P) of TTR. Analyses of the 13C-13C correlation solid-state NMR spectra revealed that WT TTR aggregates contain an amyloid core consisting of nativelike CBEF and DAGH β-sheet structures, and the mutant TTR amyloids adopt a similar amyloid core structure with nativelike CBEF and AGH β-structures. However, the V30M mutant amyloid was shown to have a different DA β-structure. In addition, strand D is more disordered even in the native state of L55P TTR, indicating that the pathogenic mutations affect the DA β-structure, leading to more effective amyloid formation. The NMR results are consistent with our mass spectrometry-based thermodynamic analyses that showed the amyloidogenic precursor states of WT and mutant TTRs adopt folded structures but the mutant precursor states are less stable than that of WT TTR. Analyses of the oxidation rate of the methionine side chain also revealed that the side chain of residue Met-30 pointing between strands D and A is not protected from oxidation in the V30M mutant, while protected in the native state, supporting the possibility that the DA β-structure might be disrupted in the V30M mutant amyloid.
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Affiliation(s)
- Kwang Hun Lim
- Department of Chemistry, East Carolina University , Greenville, North Carolina 27858, United States
| | - Anvesh K R Dasari
- Department of Chemistry, East Carolina University , Greenville, North Carolina 27858, United States
| | - Renze Ma
- Department of Chemistry, Duke University , 124 Science Drive, Durham, North Carolina 27708-0346, United States
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL) , 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL) , 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Jeffery W Kelly
- Department of Molecular and Experimental Medicine and Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Michael C Fitzgerald
- Department of Chemistry, Duke University , 124 Science Drive, Durham, North Carolina 27708-0346, United States
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25
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Hora M, Sarkar R, Morris V, Xue K, Prade E, Harding E, Buchner J, Reif B. MAK33 antibody light chain amyloid fibrils are similar to oligomeric precursors. PLoS One 2017; 12:e0181799. [PMID: 28746363 PMCID: PMC5528828 DOI: 10.1371/journal.pone.0181799] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 07/09/2017] [Indexed: 12/25/2022] Open
Abstract
Little structural information is available so far on amyloid fibrils consisting of immunoglobulin light chains. It is not understood which features of the primary sequence of the protein result in fibril formation. We report here MAS solid-state NMR studies to identify the structured core of κ-type variable domain light chain fibrils. The core contains residues of the CDR2 and the β-strands D, E, F and G of the native immunoglobulin fold. The assigned core region of the fibril is distinct in comparison to the core identified in a previous solid-state NMR study on AL-09 by Piehl at. al, suggesting that VL fibrils can adopt different topologies. In addition, we investigated a soluble oligomeric intermediate state, previously termed the alternatively folded state (AFS), using NMR and FTIR spectroscopy. The NMR oligomer spectra display a high degree of similarity when compared to the fibril spectra, indicating a high structural similarity of the two aggregation states. Based on comparison to the native state NMR chemical shifts, we suggest that fibril formation via domain-swapping seems unlikely. Moreover, we used our results to test the quality of different amyloid prediction algorithms.
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Affiliation(s)
- Manuel Hora
- Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
- Helmholtz-Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (HMGU), Neuherberg, Germany
| | - Riddhiman Sarkar
- Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
- Helmholtz-Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (HMGU), Neuherberg, Germany
| | - Vanessa Morris
- Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
- Helmholtz-Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (HMGU), Neuherberg, Germany
| | - Kai Xue
- Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
- Helmholtz-Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (HMGU), Neuherberg, Germany
| | - Elke Prade
- Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
| | - Emma Harding
- Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
| | - Johannes Buchner
- Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
| | - Bernd Reif
- Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
- Helmholtz-Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (HMGU), Neuherberg, Germany
- * E-mail:
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Chiti F, Dobson CM. Protein Misfolding, Amyloid Formation, and Human Disease: A Summary of Progress Over the Last Decade. Annu Rev Biochem 2017; 86:27-68. [DOI: 10.1146/annurev-biochem-061516-045115] [Citation(s) in RCA: 1658] [Impact Index Per Article: 236.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Peptides and proteins have been found to possess an inherent tendency to convert from their native functional states into intractable amyloid aggregates. This phenomenon is associated with a range of increasingly common human disorders, including Alzheimer and Parkinson diseases, type II diabetes, and a number of systemic amyloidoses. In this review, we describe this field of science with particular reference to the advances that have been made over the last decade in our understanding of its fundamental nature and consequences. We list the proteins that are known to be deposited as amyloid or other types of aggregates in human tissues and the disorders with which they are associated, as well as the proteins that exploit the amyloid motif to play specific functional roles in humans. In addition, we summarize the genetic factors that have provided insight into the mechanisms of disease onset. We describe recent advances in our knowledge of the structures of amyloid fibrils and their oligomeric precursors and of the mechanisms by which they are formed and proliferate to generate cellular dysfunction. We show evidence that a complex proteostasis network actively combats protein aggregation and that such an efficient system can fail in some circumstances and give rise to disease. Finally, we anticipate the development of novel therapeutic strategies with which to prevent or treat these highly debilitating and currently incurable conditions.
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Affiliation(s)
- Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio,” Section of Biochemistry, Università di Firenze, 50134 Firenze, Italy
| | - Christopher M. Dobson
- Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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