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Almeida ZL, Vaz DC, Brito RMM. Transthyretin mutagenesis: impact on amyloidogenesis and disease. Crit Rev Clin Lab Sci 2024:1-25. [PMID: 38850014 DOI: 10.1080/10408363.2024.2350379] [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: 03/12/2024] [Accepted: 04/29/2024] [Indexed: 06/09/2024]
Abstract
Transthyretin (TTR), a homotetrameric protein found in plasma, cerebrospinal fluid, and the eye, plays a pivotal role in the onset of several amyloid diseases with high morbidity and mortality. Protein aggregation and fibril formation by wild-type TTR and its natural more amyloidogenic variants are hallmarks of ATTRwt and ATTRv amyloidosis, respectively. The formation of soluble amyloid aggregates and the accumulation of insoluble amyloid fibrils and deposits in multiple tissues can lead to organ dysfunction and cell death. The most frequent manifestations of ATTR are polyneuropathies and cardiomyopathies. However, clinical manifestations such as carpal tunnel syndrome, leptomeningeal, and ocular amyloidosis, among several others may also occur. This review provides an up-to-date listing of all single amino-acid mutations in TTR known to date. Of approximately 220 single-point mutations, 93% are considered pathogenic. Aspartic acid is the residue mutated with the highest frequency, whereas tryptophan is highly conserved. "Hot spot" mutation regions are mainly assigned to β-strands B, C, and D. This manuscript also reviews the protein aggregation models that have been proposed for TTR amyloid fibril formation and the transient conformational states that convert native TTR into aggregation-prone molecular species. Finally, it compiles the various in vitro TTR aggregation protocols currently in use for research and drug development purposes. In short, this article reviews and discusses TTR mutagenesis and amyloidogenesis, and their implications in disease onset.
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Affiliation(s)
- Zaida L Almeida
- Chemistry Department and Coimbra Chemistry Centre - Institute of Molecular Sciences (CQC-IMS), University of Coimbra, Coimbra, Portugal
| | - Daniela C Vaz
- Chemistry Department and Coimbra Chemistry Centre - Institute of Molecular Sciences (CQC-IMS), University of Coimbra, Coimbra, Portugal
- School of Health Sciences, Polytechnic Institute of Leiria, Leiria, Portugal
- LSRE-LCM - Leiria, Portugal & ALiCE - Associate Laboratory in Chemical Engineering, University of Porto, Porto, Portugal
| | - Rui M M Brito
- Chemistry Department and Coimbra Chemistry Centre - Institute of Molecular Sciences (CQC-IMS), University of Coimbra, Coimbra, Portugal
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2
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Chu BK, Tsai R, Hung C, Kuo Y, Chen EH, Chiang Y, Chan SI, Chen RP. Location of the cross‐β structure in prion fibrils: A search by seeding and electron spin resonance spectroscopy. Protein Sci 2022; 31:e4326. [DOI: 10.1002/pro.4326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/15/2022] [Accepted: 04/19/2022] [Indexed: 12/19/2022]
Affiliation(s)
- Brett K.‐Y. Chu
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Ruei‐Fong Tsai
- Department of Chemistry National Tsing Hua University Hsinchu Taiwan
| | - Chien‐Lun Hung
- Department of Chemistry National Tsing Hua University Hsinchu Taiwan
| | - Yun‐Hsuan Kuo
- Department of Chemistry National Tsing Hua University Hsinchu Taiwan
| | - Eric H.‐L. Chen
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
| | - Yun‐Wei Chiang
- Department of Chemistry National Tsing Hua University Hsinchu Taiwan
| | - Sunney I. Chan
- Department of Chemistry National Taiwan University Taipei Taiwan
- Institute of Chemistry Academia Sinica Taipei Taiwan
| | - Rita P.‐Y. Chen
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
- Institute of Biochemical Sciences National Taiwan University Taipei Taiwan
- Neuroscience Program of Academia Sinica Academia Sinica Taipei Taiwan
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3
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Daskalov A, El Mammeri N, Lends A, Shenoy J, Lamon G, Fichou Y, Saad A, Martinez D, Morvan E, Berbon M, Grélard A, Kauffmann B, Ferber M, Bardiaux B, Habenstein B, Saupe SJ, Loquet A. Structures of Pathological and Functional Amyloids and Prions, a Solid-State NMR Perspective. Front Mol Neurosci 2021; 14:670513. [PMID: 34276304 PMCID: PMC8280340 DOI: 10.3389/fnmol.2021.670513] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 05/26/2021] [Indexed: 12/20/2022] Open
Abstract
Infectious proteins or prions are a remarkable class of pathogens, where pathogenicity and infectious state correspond to conformational transition of a protein fold. The conformational change translates into the formation by the protein of insoluble amyloid aggregates, associated in humans with various neurodegenerative disorders and systemic protein-deposition diseases. The prion principle, however, is not limited to pathogenicity. While pathological amyloids (and prions) emerge from protein misfolding, a class of functional amyloids has been defined, consisting of amyloid-forming domains under natural selection and with diverse biological roles. Although of great importance, prion amyloid structures remain challenging for conventional structural biology techniques. Solid-state nuclear magnetic resonance (SSNMR) has been preferentially used to investigate these insoluble, morphologically heterogeneous aggregates with poor crystallinity. SSNMR methods have yielded a wealth of knowledge regarding the fundamentals of prion biology and have helped to solve the structures of several prion and prion-like fibrils. Here, we will review pathological and functional amyloid structures and will discuss some of the obtained structural models. We will finish the review with a perspective on integrative approaches combining solid-state NMR, electron paramagnetic resonance and cryo-electron microscopy, which can complement and extend our toolkit to structurally explore various facets of prion biology.
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Affiliation(s)
- Asen Daskalov
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Nadia El Mammeri
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Alons Lends
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | | | - Gaelle Lamon
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Yann Fichou
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Ahmad Saad
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Denis Martinez
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Estelle Morvan
- CNRS, INSERM, IECB, UMS 3033, University of Bordeaux, Pessac, France
| | - Melanie Berbon
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Axelle Grélard
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
| | - Brice Kauffmann
- CNRS, INSERM, IECB, UMS 3033, University of Bordeaux, Pessac, France
| | | | | | | | - Sven J. Saupe
- CNRS, IBGC UMR 5095, University of Bordeaux, Bordeaux, France
| | - Antoine Loquet
- CNRS, CBMN UMR 5348, IECB, University of Bordeaux, Pessac, France
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4
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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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5
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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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6
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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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7
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Transthyretin amyloidosis: an under-recognized neuropathy and cardiomyopathy. Clin Sci (Lond) 2017; 131:395-409. [PMID: 28213611 DOI: 10.1042/cs20160413] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/07/2016] [Accepted: 12/15/2016] [Indexed: 12/18/2022]
Abstract
Transthyretin (TTR) amyloidosis (ATTR amyloidosis) is an underdiagnosed and important type of cardiomyopathy and/or polyneuropathy that requires increased awareness within the medical community. Raising awareness among clinicians about this type of neuropathy and lethal form of heart disease is critical for improving earlier diagnosis and the identification of patients for treatment. The following review summarizes current criteria used to diagnose both hereditary and wild-type ATTR (ATTRwt) amyloidosis, tools available to clinicians to improve diagnostic accuracy, available and newly developing therapeutics, as well as a brief biochemical and biophysical background of TTR amyloidogenesis.
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8
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Bertolani A, Pizzi A, Pirrie L, Gazzera L, Morra G, Meli M, Colombo G, Genoni A, Cavallo G, Terraneo G, Metrangolo P. Crystal Structure of the DFNKF Segment of Human Calcitonin Unveils Aromatic Interactions between Phenylalanines. Chemistry 2017; 23:2051-2058. [PMID: 27806188 PMCID: PMC5573999 DOI: 10.1002/chem.201604639] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Indexed: 12/24/2022]
Abstract
Although intensively studied, the high-resolution crystal structure of the peptide DFNKF, the core-segment of human calcitonin, has never been described. Here we report how the use of iodination as a strategy to promote crystallisation and facilitate phase determination, allowed us to solve, for the first time, the single-crystal X-ray structure of a DFNKF derivative. Computational studies suggest that both the iodinated and the wild-type peptides populate very similar conformations. Furthermore, the conformer found in the solid-state structure is one of the most populated in solution, making the crystal structure a reliable model for the peptide in solution. The crystal structure of DFNKF(I) confirms the overall features of the amyloid cross-β spine and highlights how aromatic-aromatic interactions are important structural factors in the self-assembly of this peptide. A detailed analysis of such interactions is reported.
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Affiliation(s)
- Arianna Bertolani
- Laboratory of Nanostructured Fluorinated Materials (NFMLab)Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”Politecnico di MilanoVia L. Mancinelli 720131MilanoItaly
| | - Andrea Pizzi
- Laboratory of Nanostructured Fluorinated Materials (NFMLab)Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”Politecnico di MilanoVia L. Mancinelli 720131MilanoItaly
| | - Lisa Pirrie
- Laboratory of Nanostructured Fluorinated Materials (NFMLab)Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”Politecnico di MilanoVia L. Mancinelli 720131MilanoItaly
| | - Lara Gazzera
- Laboratory of Nanostructured Fluorinated Materials (NFMLab)Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”Politecnico di MilanoVia L. Mancinelli 720131MilanoItaly
| | - Giulia Morra
- Istituto di Chimica del Riconoscimento MolecolareCNRVia Mario Bianco 920131MilanoItaly
| | - Massimiliano Meli
- Istituto di Chimica del Riconoscimento MolecolareCNRVia Mario Bianco 920131MilanoItaly
| | - Giorgio Colombo
- Istituto di Chimica del Riconoscimento MolecolareCNRVia Mario Bianco 920131MilanoItaly
| | - Alessandro Genoni
- Laboratoire SRSMC, UMR 7565CNRSVandoeuvre-lès-Nancy54506France
- Laboratoire SRSMC, UMR 7565Université de LorraineVandoeuvre-lès-Nancy54506France
| | - Gabriella Cavallo
- Laboratory of Nanostructured Fluorinated Materials (NFMLab)Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”Politecnico di MilanoVia L. Mancinelli 720131MilanoItaly
| | - Giancarlo Terraneo
- Laboratory of Nanostructured Fluorinated Materials (NFMLab)Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”Politecnico di MilanoVia L. Mancinelli 720131MilanoItaly
| | - Pierangelo Metrangolo
- Laboratory of Nanostructured Fluorinated Materials (NFMLab)Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”Politecnico di MilanoVia L. Mancinelli 720131MilanoItaly
- Istituto di Chimica del Riconoscimento MolecolareCNRVia Mario Bianco 920131MilanoItaly
- HYBER Centre of ExcellenceDepartment of Applied PhysicsAalto University, P.O. Box 1510002150EspooFinland
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9
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Pires RH, Saraiva MJ, Damas AM, Kellermayer MSZ. Force spectroscopy reveals the presence of structurally modified dimers in transthyretin amyloid annular oligomers. J Mol Recognit 2016; 30. [PMID: 27808434 DOI: 10.1002/jmr.2587] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 09/21/2016] [Accepted: 09/30/2016] [Indexed: 12/17/2022]
Abstract
Toxicity in amyloidogenic protein misfolding disorders is thought to involve intermediate states of aggregation associated with the formation of amyloid fibrils. Despite their relevance, the heterogeneity and transience of these oligomers have placed great barriers in our understanding of their structural properties. Among amyloid intermediates, annular oligomers or annular protofibrils have raised considerable interest because they may contribute to a mechanism of cellular toxicity via membrane permeation. Here we investigated, by using AFM force spectroscopy, the structural detail of amyloid annular oligomers from transthyretin (TTR), a protein involved in systemic and neurodegenerative amyloidogenic disorders. Manipulation was performed in situ, in the absence of molecular handles and using persistence length-fit values to select relevant curves. Force curves reveal the presence of dimers in TTR annular oligomers that unfold via a series of structural intermediates. This is in contrast with the manipulation of native TTR that was more often manipulated over length scales compatible with a TTR monomer and without unfolding intermediates. Imaging and force spectroscopy data suggest that dimers are formed by the assembly of monomers in a head-to-head orientation with a nonnative interface along their β-strands. Furthermore, these dimers stack through nonnative contacts that may enhance the stability of the misfolded structure.
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Affiliation(s)
- Ricardo H Pires
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary.,Institute for Molecular and Cell Biology (IBMC), Porto, Portugal
| | - Maria J Saraiva
- Institute for Molecular and Cell Biology (IBMC), Porto, Portugal.,Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Ana M Damas
- Institute for Molecular and Cell Biology (IBMC), Porto, Portugal.,Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Miklós S Z Kellermayer
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary.,MTA-SE Molecular Biophysics Research Group, Budapest, Hungary
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10
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Groenning M, Campos RI, Hirschberg D, Hammarström P, Vestergaard B. Considerably Unfolded Transthyretin Monomers Preceed and Exchange with Dynamically Structured Amyloid Protofibrils. Sci Rep 2015; 5:11443. [PMID: 26108284 PMCID: PMC4480009 DOI: 10.1038/srep11443] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/23/2015] [Indexed: 11/09/2022] Open
Abstract
Despite numerous studies, a detailed description of the transthyretin (TTR) self-assembly mechanism and fibril structure in TTR amyloidoses remains unresolved. Here, using a combination of primarily small -angle X-ray scattering (SAXS) and hydrogen exchange mass spectrometry (HXMS) analysis, we describe an unexpectedly dynamic TTR protofibril structure which exchanges protomers with highly unfolded monomers in solution. The protofibrils only grow to an approximate final size of 2,900 kDa and a length of 70 nm and a comparative HXMS analysis of native and aggregated samples revealed a much higher average solvent exposure of TTR upon fibrillation. With SAXS, we reveal the continuous presence of a considerably unfolded TTR monomer throughout the fibrillation process, and show that a considerable fraction of the fibrillating protein remains in solution even at a late maturation state. Together, these data reveal that the fibrillar state interchanges with the solution state. Accordingly, we suggest that TTR fibrillation proceeds via addition of considerably unfolded monomers, and the continuous presence of amyloidogenic structures near the protofibril surface offers a plausible explanation for secondary nucleation. We argue that the presence of such dynamic structural equilibria must impact future therapeutic development strategies.
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Affiliation(s)
- Minna Groenning
- Department of Pharmacy and Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- IFM – Department of Chemistry, Linköping University, Linköping, Sweden
| | - Raul I. Campos
- IFM – Department of Chemistry, Linköping University, Linköping, Sweden
| | - Daniel Hirschberg
- IFM – Department of Chemistry, Linköping University, Linköping, Sweden
| | - Per Hammarström
- IFM – Department of Chemistry, Linköping University, Linköping, Sweden
| | - Bente Vestergaard
- Department of Pharmacy and Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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11
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Haupt M, Blakeley MP, Fisher SJ, Mason SA, Cooper JB, Mitchell EP, Forsyth VT. Binding site asymmetry in human transthyretin: insights from a joint neutron and X-ray crystallographic analysis using perdeuterated protein. IUCRJ 2014; 1:429-38. [PMID: 25485123 PMCID: PMC4224461 DOI: 10.1107/s2052252514021113] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 09/22/2014] [Indexed: 05/12/2023]
Abstract
Human transthyretin has an intrinsic tendency to form amyloid fibrils and is heavily implicated in senile systemic amyloidosis. Here, detailed neutron structural studies of perdeuterated transthyretin are described. The analyses, which fully exploit the enhanced visibility of isotopically replaced hydrogen atoms, yield new information on the stability of the protein and the possible mechanisms of amyloid formation. Residue Ser117 may play a pivotal role in that a single water molecule is closely associated with the γ-hydrogen atoms in one of the binding pockets, and could be important in determining which of the two sites is available to the substrate. The hydrogen-bond network at the monomer-monomer interface is more extensive than that at the dimer-dimer interface. Additionally, the edge strands of the primary dimer are seen to be favourable for continuation of the β-sheet and the formation of an extended cross-β structure through sequential dimer couplings. It is argued that the precursor to fibril formation is the dimeric form of the protein.
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Affiliation(s)
- Melina Haupt
- Facility of Natural Sciences, Institute of Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom
- Institut Laue-Langevin, 71, avenue des Martyrs, Grenoble, CS 20156, France
- Partnership for Structural Biology, 71, avenue des Martyrs, Grenoble, CS 20156, France
| | - Matthew P. Blakeley
- Institut Laue-Langevin, 71, avenue des Martyrs, Grenoble, CS 20156, France
- Partnership for Structural Biology, 71, avenue des Martyrs, Grenoble, CS 20156, France
| | - Stuart J. Fisher
- Department of Molecular Biology, University of Salzburg, Billrothstrasse 11, Salzburg, 5020, Austria
- Diamond Light Source, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Sax A. Mason
- Institut Laue-Langevin, 71, avenue des Martyrs, Grenoble, CS 20156, France
| | - Jon B. Cooper
- Division of Medicine (Royal Free Campus), University College London, Rowland Hill Street, London NW3 2PF, United Kingdom
| | - Edward P. Mitchell
- Facility of Natural Sciences, Institute of Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom
- Partnership for Structural Biology, 71, avenue des Martyrs, Grenoble, CS 20156, France
- Business Development Office, European Synchrotron Radiation Facility, Grenoble, 38042, France
| | - V. Trevor Forsyth
- Facility of Natural Sciences, Institute of Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom
- Institut Laue-Langevin, 71, avenue des Martyrs, Grenoble, CS 20156, France
- Partnership for Structural Biology, 71, avenue des Martyrs, Grenoble, CS 20156, France
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12
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Conti S, Li X, Gianni S, Ghadami SA, Buxbaum J, Cecchi C, Chiti F, Bemporad F. A Complex Equilibrium among Partially Unfolded Conformations in Monomeric Transthyretin. Biochemistry 2014; 53:4381-92. [DOI: 10.1021/bi500430w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Simona Conti
- Dipartimento
di Scienze Biomediche Sperimentali e Cliniche “Mario Serio”,
Sezione di Biochimica, Università degli Studi di Firenze, Viale G. B. Morgagni 50, 50134 Firenze, Italy
| | - Xinyi Li
- Department
of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, MEM-230, La
Jolla, California 92037, United States
| | - Stefano Gianni
- Istituto
Pasteur Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche
“A. Rossi Fanelli”, Istituto di Biologia e Patologia
Molecolari del CNR, Università di Roma “La Sapienza”, P. le A. Moro 5, 00185 Roma, Italy
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Seyyed Abolghasem Ghadami
- Dipartimento
di Scienze Biomediche Sperimentali e Cliniche “Mario Serio”,
Sezione di Biochimica, Università degli Studi di Firenze, Viale G. B. Morgagni 50, 50134 Firenze, Italy
| | - Joel Buxbaum
- Department
of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, MEM-230, La
Jolla, California 92037, United States
| | - Cristina Cecchi
- Dipartimento
di Scienze Biomediche Sperimentali e Cliniche “Mario Serio”,
Sezione di Biochimica, Università degli Studi di Firenze, Viale G. B. Morgagni 50, 50134 Firenze, Italy
| | - Fabrizio Chiti
- Dipartimento
di Scienze Biomediche Sperimentali e Cliniche “Mario Serio”,
Sezione di Biochimica, Università degli Studi di Firenze, Viale G. B. Morgagni 50, 50134 Firenze, Italy
| | - Francesco Bemporad
- Dipartimento
di Scienze Biomediche Sperimentali e Cliniche “Mario Serio”,
Sezione di Biochimica, Università degli Studi di Firenze, Viale G. B. Morgagni 50, 50134 Firenze, Italy
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13
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Abstract
The amyloidoses are a group of protein misfolding diseases in which the precursor protein undergoes a conformational change that triggers the formation of amyloid fibrils in different tissues and organs, causing cell death and organ failure. Amyloidoses can be either localized or systemic. In localized amyloidosis, amyloid deposits form at the site of precursor protein synthesis, whereas in systemic amyloidosis, amyloid deposition occurs distant from the site of precursor protein secretion. We review the type of proteins and cells involved and what is known about the complex pathophysiology of these diseases. We focus on light chain amyloidosis to illustrate how biochemical and biophysical studies have led to a deeper understanding of the pathogenesis of this devastating disease. We also review current cellular, tissue, and animal models and discuss the challenges and opportunities for future studies of the systemic amyloidoses.
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Affiliation(s)
- Luis M Blancas-Mejía
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA.
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14
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Abstract
Amyloid fibers and oligomers are associated with a great variety of human diseases including Alzheimer's disease and the prion conditions. Here we attempt to connect recent discoveries on the molecular properties of proteins in the amyloid state with observations about pathological tissues and disease states. We summarize studies of structure and nucleation of amyloid and relate these to observations on amyloid polymorphism, prion strains, coaggregation of pathogenic proteins in tissues, and mechanisms of toxicity and transmissibility. Molecular studies have also led to numerous strategies for biological and chemical interventions against amyloid diseases.
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Affiliation(s)
- David Eisenberg
- Howard Hughes Medical Institute, Department of Biological Chemistry, University of California, Los Angeles, Los Angeles CA 90095-1570, USA.
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15
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Bateman DA, Tycko R, Wickner RB. Experimentally derived structural constraints for amyloid fibrils of wild-type transthyretin. Biophys J 2011; 101:2485-92. [PMID: 22098747 DOI: 10.1016/j.bpj.2011.10.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 10/04/2011] [Accepted: 10/11/2011] [Indexed: 11/30/2022] Open
Abstract
Transthyretin (TTR) is a largely β-sheet serum protein responsible for transporting thyroxine and vitamin A. TTR is found in amyloid deposits of patients with senile systemic amyloidosis. TTR mutants lead to familial amyloidotic polyneuropathy and familial amyloid cardiomyopathy, with an earlier age of onset. Studies of amyloid fibrils of familial amyloidotic polyneuropathy mutant TTR suggest a structure similar to the native state with only a simple opening of a β-strand-loop-strand region exposing the two main β-sheets of the protein for fibril elongation. However, we find that the wild-type TTR sequence forms amyloid fibrils that are considerably different from the previously suggested amyloid structure. Using protease digestion with mass spectrometry, we observe the amyloid core to be primarily composed of the C-terminal region, starting around residue 50. Solid-state NMR measurements prove that TTR differs from other pathological amyloids in not having an in-register parallel β-sheet architecture. We also find that the TTR amyloid is incapable of binding thyroxine as monitored by either isothermal calorimetry or 1,8-anilinonaphthalene sulfonate competition. Taken together, our experiments are consistent with a significantly different configuration of the β-sheets compared to the previously suggested structure.
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Affiliation(s)
- David A Bateman
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda Maryland, USA
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16
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Groenning M, Campos RI, Fagerberg C, Rasmussen AA, Eriksen UH, Powers ET, Hammarström P. Thermodynamic stability and denaturation kinetics of a benign natural transthyretin mutant identified in a Danish kindred. Amyloid 2011; 18:35-46. [PMID: 21406045 DOI: 10.3109/13506129.2011.560215] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The disease phenotype of transthyretin (TTR) is dramatically influenced by single point mutations in the TTR gene. Herein, we report on a novel mutation D99N (Asp99Asn) in TTR found in a Danish kindred. None of the family members carrying this mutation have so far shown any clinical signs of amyloidosis. One carrier found compound heterozygous for TTR D99N and L111M (Leu111Met) associated with cardiac amyloid is asymptomatic (42 years). Disease severity can often be linked to both the kinetics of fibril formation and the degree of destabilisation of the native state. In this study, we show that the thermodynamic stability and rate of tetramer dissociation of the variant TTR D99N is unchanged or slightly more stable than wild type (WT) TTR. Furthermore, the in vitro fibrillation kinetics of the variant reveals an unchanged or slightly suppressed tendency to form fibrils compared to WT. Thus, the in vitro experiments support the lack of clinical symptoms observed so far for the TTR D99N carriers. In line with this, studies on kinetic stability and fibrillation kinetics reveal indistinguishable stability of TTR heterotetramers D99N/L111M compared to the heterotetramers WT/L111M. In conclusion, TTR D99N is predicted to be a non-pathogenic benign mutation with WT properties.
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Affiliation(s)
- Minna Groenning
- Department of Pharmaceutics and Analytical Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Denmark.
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17
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Žerovnik E, Stoka V, Mirtič A, Gunčar G, Grdadolnik J, Staniforth RA, Turk D, Turk V. Mechanisms of amyloid fibril formation--focus on domain-swapping. FEBS J 2011; 278:2263-82. [PMID: 21535473 DOI: 10.1111/j.1742-4658.2011.08149.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Conformational diseases constitute a group of heterologous disorders in which a constituent host protein undergoes changes in conformation, leading to aggregation and deposition. To understand the molecular mechanisms of the process of amyloid fibril formation, numerous in vitro and in vivo studies, including model and pathologically relevant proteins, have been performed. Understanding the molecular details of these processes is of major importance to understand neurodegenerative diseases and could contribute to more effective therapies. Many models have been proposed to describe the mechanism by which proteins undergo ordered aggregation into amyloid fibrils. We classify these as: (a) templating and nucleation; (b) linear, colloid-like assembly of spherical oligomers; and (c) domain-swapping. In this review, we stress the role of domain-swapping and discuss the role of proline switches.
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Affiliation(s)
- Eva Žerovnik
- Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia.
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18
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Zerovnik E. Oligomerization preceding amyloid fibril formation: a process in common to intrinsically disordered and globular proteins. NETWORK (BRISTOL, ENGLAND) 2011; 22:154-161. [PMID: 22149676 DOI: 10.3109/0954898x.2011.639842] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Neurodegenerative diseases present a big burden to society. At the molecular level many of them - if not all - show protein aggregation (as an epiphenomenon or as a cause). The knowledge on details of thermodynamics and kinetics as well as structure of the protein aggregates, especially the early and soluble oligomers, may help in designing inhibitors for early stages of such diseases. Here, a possible outlook on more general mechanism for their formation is discussed. The oligomers of amyloid forming proteins, which are present prior and during nucleation and amyloid fibril formation, are claimed to be toxic to cells. Oligomers of the globular proteins and the intrinsically disordered proteins (IDPs), form in vitro upon partial denaturation and renaturation, respectively. Often they form if the sample is heated or freeze-thawed for a few cycles. A question is asked if this does not highlight one important property in common to globular proteins and IDPs, namely, a high energetic barrier dividing such oligomers from the monomers. This also would imply existence of two populations of states, one, the monomer - being metastable - at least under the conditions, which promote fibril formation.
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Affiliation(s)
- Eva Zerovnik
- Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia.
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19
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Abstract
The amyloid hypothesis indicates that protein misfolding is at the root of many neurodegenerative disorders. Small molecules targeting the formation, clearance, aggregation to toxic oligomers or SOD (superoxide dismutase)-like activities of Aβ (amyloid β-peptide) 1–42 have provided encouraging candidates for AD (Alzheimer's disease) medicines in animal models, although none have yet proved to be effective in human trials. We have been investigating approaches to treat systemic amyloidoses, conditions that show common features with some CNS (central nervous system) disorders. For TTR (transthyretin) amyloidosis, we are seeking small molecule compounds that stabilize the amyloidogenic protein and either prevent its structural transition to the crossed β fibres deposited in diseased tissues, or promote its clearance from circulation. Effective stabilizer compounds that simultaneously bind to both thyroxine-binding sites have been developed. A more generic approach involves targeting the plasma glycoprotein SAP (serum amyloid P component). This protein recognizes the misfolded polypeptide structures of amyloid deposits wherever they occur, and acts as a powerful anti-opsonin. We have developed a bivalent drug called CPHPC {(R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]-pyrrolidine-2-carboxylic acid} that cross-links pairs of pentameric SAP molecules and causes their rapid elimination from the circulation. This strategy raises the prospect of encouraging natural mechanisms to clear amyloid and recent work suggests that this approach extends to the CNS.
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20
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Trivella DBB, Bleicher L, Palmieri LDC, Wiggers HJ, Montanari CA, Kelly JW, Lima LMTR, Foguel D, Polikarpov I. Conformational differences between the wild type and V30M mutant transthyretin modulate its binding to genistein: implications to tetramer stability and ligand-binding. J Struct Biol 2010; 170:522-31. [PMID: 20211733 DOI: 10.1016/j.jsb.2010.03.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 02/27/2010] [Accepted: 03/02/2010] [Indexed: 11/26/2022]
Abstract
Transthyretin (TTR) is a tetrameric beta-sheet-rich transporter protein directly involved in human amyloid diseases. It was recently found that the isoflavone genistein (GEN) potently inhibits TTR amyloid fibril formation (Green et al., 2005) and is therefore a promising candidate for TTR amyloidosis treatment. Here we used structural and biophysical approaches to characterize genistein binding to the wild type (TTRwt) and to its most frequent amyloidogenic variant, the V30M mutant. In a dose-dependent manner, genistein elicited considerable increases in both mutant and TTRwt stability as demonstrated by high hydrostatic pressure (HHP) and acid-mediated dissociation/denaturation assays. TTR:GEN crystal complexes and isothermal titration calorimetry (ITC) experiments showed that the binding mechanisms of genistein to the TTRwt and to V30M are different and are dependent on apoTTR structure conformations. Furthermore, we could also identify potential allosteric movements caused by genistein binding to the wild type TTR that explains, at least in part, the frequently observed negatively cooperative process between the two sites of TTRwt when binding ligands. These findings show that TTR mutants may present different ligand recognition and therefore are of value in ligand design for inhibiting TTR amyloidosis.
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Affiliation(s)
- Daniela B B Trivella
- Instituto de Física de São Carlos, Universidade de São Paulo, P.O. Box 369, 13560-970 São Carlos, SP, Brazil
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21
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Skerget K, Vilfan A, Pompe-Novak M, Turk V, Waltho JP, Turk D, Zerovnik E. The mechanism of amyloid-fibril formation by stefin B: temperature and protein concentration dependence of the rates. Proteins 2009; 74:425-36. [PMID: 18636508 DOI: 10.1002/prot.22156] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cystatins, a family of structurally related cysteine proteinase inhibitors, have proved to be useful model system to study amyloidogenesis. We have extended previous studies of the kinetics of amyloid-fibril formation by human stefin B (cystatin B) and some of its mutants, and proposed an improved model for the reaction. Overall, the observed kinetics follow the nucleation and growth behavior observed for many other amyloidogenic proteins. The minimal kinetic scheme that best fits measurements of changes in CD and thioflavin T fluorescence as a function of protein concentration and temperature includes nucleation (modeled as N(I) irreversible transitions with equivalent rates (k(I)), which fitted with N(I) = 64), fibril growth and nonproductive oligomerization, best explained by an off-pathway state with a rate-limiting escape rate. Three energies of activation were derived from global fitting to the minimal kinetic scheme, and independently through the fitting of the individual component rates. Nucleation was found to be a first-order process within an oligomeric species with an enthalpy of activation of 55 +/- 4 kcal mol(-1). Fibril growth was a second-order process with an enthalpy of activation (27 +/- 5 kcal mol(-1)), which is indistinguishable from that of tetramer formation by cystatins, which involves limited conformational changes including proline trans to cis isomerization. The highest enthalpy of activation (95 +/- 5 kcal mol(-1) at 35 degrees C), characteristic of a substantial degree of unfolding as observed prior to domain-swapping reactions, equated with the escape rate of the off-pathway oligomeric state.
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Affiliation(s)
- Katja Skerget
- Department of Biochemistry, Molecular and Structural Biology, JoZef Stefan Institute, 1000 Ljubljana, Slovenia
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22
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Abstract
The conversion of proteins from their soluble states into well-organized fibrillar aggregates is associated with a wide range of pathological conditions, including neurodegenerative diseases and systemic amyloidoses. In this review, we discuss the mechanism of aggregation of globular proteins under conditions in which they are initially folded. Although a conformational change of the native state is generally necessary to initiate aggregation, we show that a transition across the major energy barrier for unfolding is not essential and that aggregation may well be initiated from locally unfolded states that become accessible, for example, via thermal fluctuations occurring under physiological conditions. We review recent evidence on this topic and discuss its significance for understanding the onset and potential inhibition of protein aggregation in the context of diseases.
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Affiliation(s)
- Fabrizio Chiti
- Dipartimento di Scienze Biochimiche, Università degli Studi di Firenze, Viale Morgagni 50, I-50134 Firenze, Italy.
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23
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Lindhagen-Persson M, Vestling M, Reixach N, Olofsson A. Formation of cytotoxic transthyretin is not dependent on inter-molecular disulphide bridges commonly found within the amyloid form. Amyloid 2008; 15:240-5. [PMID: 19065295 DOI: 10.1080/13506120802524916] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Familial amyloidotic polyneuropathy (FAP) is linked to destabilising point mutations in the human plasma protein transthyretin (TTR). Consistent with similar amyloid disorders, low molecular weight TTR oligomers have been shown to exert the major cytotoxic effect. The amyloid structure of TTR contains non-native inter-molecular disulphide linkages via the cysteine at position 10 (Cys10). Moreover, substitution of Cys10 in a mouse model for TTR-amyloidosis abolishes TTR deposits, indicating an important role of Cys10 in FAP pathogenesis. However, the role of disulphide bridges in TTR cytotoxicity has not been elucidated. By probing Cys10Ser TTR variants to the human neuroblastoma SH-SY5Y cell line, we have addressed this question, and our results clearly show that formation of an inter-molecular disulphide bridge is not a pre-requisite for TTR cytotoxicity. This finding suggests that prevention of inter-molecular TTR disulphide bridges as a therapeutic intervention will not impair the cytotoxic potential of TTR.
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24
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Zerovnik E, Skarabot M, Skerget K, Giannini S, Stoka V, Jenko-Kokalj S, Staniforth RA. Amyloid fibril formation by human stefin B: influence of pH and TFE on fibril growth and morphology. Amyloid 2007; 14:237-47. [PMID: 17701471 DOI: 10.1080/13506120701461137] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
As shown before, human stefin B (cystatin B) populates two partly unfolded species, a native-like state at pH 4.8 and a structured molten globule state at pH 3.3 (high ionic strength), from each of which amyloid fibrils grow. Here, we show that the fibrils obtained at pH 3.3 differ from those at pH 4.8 and that those obtained at pH 3.3 (protofibrils) do not transform readily to mature fibrils. In addition we show that amorphous aggregates are also a source of fibrils. The kinetics of amyloid fibril formation at different trifluoroethanol (TFE) concentrations were measured. TFE accelerates fibril growth at predenaturational concentrations of the alcohol. At concentrations higher than 10%, the fibrillar yield decreases proportionately as the population of an all alpha-helical, denatured form of the protein increases. At an optimum TFE concentration, the lag and the growth phases are observed, similarly to some other amyloidogenic proteins. Morphology of the protein species at the beginning and the end of the reactions was observed using atomic force microscopy and transmission electron microscopy. Final fibril morphologies differ depending on solvent conditions.
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Affiliation(s)
- Eva Zerovnik
- Department of Biochemistry, Molecular and Structural Biology, Josef Stefan Institute, Ljubljana, Slovenia.
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25
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Sørensen J, Hamelberg D, Schiøtt B, McCammon JA. Comparative MD analysis of the stability of transthyretin providing insight into the fibrillation mechanism. Biopolymers 2007; 86:73-82. [PMID: 17315201 DOI: 10.1002/bip.20705] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Proteins can misfold and aggregate, which is believed to be the cause of a variety of diseases, affecting very diverse organs in the body. Many questions about the nature of aggregation and the proteins that are involved in these events are still left unanswered. One of the proteins that is known to form amyloids is transthyretin (TTR), the secondary transporter of thyroxine, and transporter of retinol-binding protein. Several experimental results have helped to explain this aberrant behavior of TTR; however, structural insights of the amyloidgenic process are still lacking. Therefore, we have used all-atom MD simulation and free energy calculations to study the initial phase of this process. We have calculated the free energy changes of the initial tetramer dissociation under different conditions and in the presence of thyroxine. We show that tetramer formation is indeed only thermodynamically favorable in neutral pH conditions. We find that binding of two thyroxine molecules stabilizes the complex, and that this occurs with negative cooperativity. In addition to the energetic calculations, we have also investigated the dominant motions of the TTR and found that only the dimeric form of the protein could undergo the initial fibril formation.
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Affiliation(s)
- Jesper Sørensen
- Department of Chemistry, Aarhus University, Aarhus C, 8000, Denmark
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26
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Abstract
Familial amyloidotic polyneuropathy (FAP) is an inherited autosomal dominant disease that is commonly caused by accumulation of deposits of transthyretin (TTR) amyloid around peripheral nerves. The only effective treatment for FAP is liver transplantation. However, recent studies on TTR aggregation provide clues to the mechanism of the molecular pathogenesis of FAP and suggest new avenues for therapeutic intervention. It is increasingly recognized that there are common features of a number of protein-misfolding diseases that can lead to neurodegeneration. As for other amyloidogenic proteins, the most toxic forms of aggregated TTR are likely to be the low-molecular-mass diffusible species, and there is increasing evidence that this toxicity is mediated by disturbances in calcium homeostasis. This article reviews what is already known about the mechanism of TTR aggregation in FAP and describes how recent discoveries in other areas of amyloid research, particularly Alzheimer's disease, provide clues to the molecular pathogenesis of FAP.
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Affiliation(s)
- Xu Hou
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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27
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Bergström J, Engström U, Yamashita T, Ando Y, Westermark P. Surface exposed epitopes and structural heterogeneity of in vivo formed transthyretin amyloid fibrils. Biochem Biophys Res Commun 2006; 348:532-9. [PMID: 16893521 DOI: 10.1016/j.bbrc.2006.07.140] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Accepted: 07/17/2006] [Indexed: 10/24/2022]
Abstract
We have investigated the structure of in vivo formed transthyretin (TTR) amyloid deposits by using antisera raised against short linear sequences of the TTR molecule. In immunohistochemistry, antisera anti-TTR41-50 and anti-TTR115-124-a reacted specifically with both wildtype ATTR and ATTR V30M material, whereas only anti-TTR41-50 recognized ATTR Y114C material. Similar results were obtained by ELISA analysis of ATTR V30M and ATTR Y114C vitreous amyloid, where the anti-TTR115-124-a antiserum failed to react with ATTR Y114C material. Moreover, neither of the antisera recognized natively structured TTR present in pancreatic alpha cells. Our results strongly indicate that the TTR molecule undergoes structural changes during fibrillogenesis in vivo. The finding of a structural difference between wildtype ATTR and ATTR V30M material on one hand and ATTR Y114C material on the other suggests that the fibril formation pathway of these ATTR variants may differ in vivo.
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Affiliation(s)
- Joakim Bergström
- Department of Genetics and Pathology, Uppsala University, Uppsala, Sweden.
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28
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Laidman J, Forse GJ, Yeates TO. Conformational change and assembly through edge beta strands in transthyretin and other amyloid proteins. Acc Chem Res 2006; 39:576-83. [PMID: 16981673 DOI: 10.1021/ar050017s] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Numerous diseases are characterized by the formation of insoluble, amyloid protein fibrils. Intensive investigations are beginning to unravel the detailed molecular and structural principles that underlie the spontaneous formation of these fibrils. The amyloid protein transthyretin serves as an excellent system for dissecting the conformational changes and ensuing subunit-subunit associations that lead to amyloid. One working model for tranthyretin amyloid involves the exposure of an "unprotected" edge beta strand, followed by symmetric assembly of subunits to give head-to-head and tail-to-tail protofibrils. The models and principles emerging from studies on transthyretin lead to connections to other amyloid systems.
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Affiliation(s)
- Janel Laidman
- Department of Chemistry and Biochemistry, University of California-Los Angeles (UCLA), Post Office Box 951569, Los Angeles, CA 90095-1569, USA
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29
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Cecchini M, Curcio R, Pappalardo M, Melki R, Caflisch A. A molecular dynamics approach to the structural characterization of amyloid aggregation. J Mol Biol 2006; 357:1306-21. [PMID: 16483608 DOI: 10.1016/j.jmb.2006.01.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 11/21/2005] [Accepted: 01/04/2006] [Indexed: 10/25/2022]
Abstract
A novel computational approach to the structural analysis of ordered beta-aggregation is presented and validated on three known amyloidogenic polypeptides. The strategy is based on the decomposition of the sequence into overlapping stretches and equilibrium implicit solvent molecular dynamics (MD) simulations of an oligomeric system for each stretch. The structural stability of the in-register parallel aggregates sampled in the implicit solvent runs is further evaluated using explicit water simulations for a subset of the stretches. The beta-aggregation propensity along the sequence of the Alzheimer's amyloid-beta peptide (Abeta(42)) is found to be highly heterogeneous with a maximum in the segment V(12)HHQKLVFFAE(22) and minima at S(8)G(9), G(25)S(26), G(29)A(30), and G(38)V(39), which are turn-like segments. The simulation results suggest that these sites may play a crucial role in determining the aggregation tendency and the fibrillar structure of Abeta(42). Similar findings are obtained for the human amylin, a 37-residue peptide that displays a maximal beta-aggregation propensity at Q(10)RLANFLVHSSNN(22) and two turn-like sites at G(24)A(25) and G(33)S(34). In the third application, the MD approach is used to identify beta-aggregation "hot-spots" within the N-terminal domain of the yeast prion Ure2p (Ure2p(1-94)) and to design a double-point mutant (Ure2p-N4748S(1-94)) with lower beta-aggregation propensity. The change in the aggregation propensity of Ure2p-N4748S(1-94) is verified in vitro using the thioflavin T binding assay.
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Affiliation(s)
- M Cecchini
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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30
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Abstract
Amyloid fibrils are elongated, insoluble protein aggregates deposited in vivo in amyloid diseases, and amyloid-like fibrils are formed in vitro from soluble proteins. Both of these groups of fibrils, despite differences in the sequence and native structure of their component proteins, share common properties, including their core structure. Multiple models have been proposed for the common core structure, but in most cases, atomic-level structural details have yet to be determined. Here we review several structural models proposed for amyloid and amyloid-like fibrils and relate features of these models to the common fibril properties. We divide models into three classes: Refolding, Gain-of-Interaction, and Natively Disordered. The Refolding models propose structurally distinct native and fibrillar states and suggest that backbone interactions drive fibril formation. In contrast, the Gain-of-Interaction models propose a largely native-like structure for the protein in the fibril and highlight the importance of specific sequences in fibril formation. The Natively Disordered models have aspects in common with both Refolding and Gain-of-Interaction models. While each class of model suggests explanations for some of the common fibril properties, and some models, such as Gain-of-Interaction models with a cross-beta spine, fit a wider range of properties than others, no one class provides a complete explanation for all amyloid fibril behavior.
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Affiliation(s)
- Rebecca Nelson
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, UCLA, Los Angeles, California 90095, USA
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31
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Correia BE, Loureiro-Ferreira N, Rodrigues JR, Brito RMM. A structural model of an amyloid protofilament of transthyretin. Protein Sci 2005; 15:28-32. [PMID: 16322570 PMCID: PMC2242366 DOI: 10.1110/ps.051787106] [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: 10/25/2022]
Abstract
A docking-and-alignment protocol was devised in order to build amyloid protofilaments of Transthyretin (TTR), starting from partially disrupted TTR monomeric subunits and based on experimentally available information. The docking approach is driven by a combination of shape complementarity and energetic criteria, and uses constraints derived from experimental data obtained for the fibrillar state. The dimeric structures obtained were then subjected to an alignment scheme followed by clustering analysis, producing a collection of protofilaments with distinct geometric properties. The selected protofilament model presented here does agree with known experimental data and general amyloid properties; it is formed by two extended continuous beta-sheets with the beta-strands perpendicular to the main axis of the protofilament and a helical twist with a period of approximately 48 beta-strands. This TTR proto-filament model may be an important step in the understanding of the molecular mechanisms of TTR aggregation, as well as, a valuable instrument in drug design strategies against amyloid diseases.
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Affiliation(s)
- Bruno E Correia
- Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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32
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Gales L, Macedo-Ribeiro S, Arsequell G, Valencia G, Saraiva M, Damas A. Human transthyretin in complex with iododiflunisal: structural features associated with a potent amyloid inhibitor. Biochem J 2005; 388:615-21. [PMID: 15689188 PMCID: PMC1138969 DOI: 10.1042/bj20042035] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ex vivo and in vitro studies have revealed the remarkable amyloid inhibitory potency and specificity of iododiflunisal in relation to transthyretin [Almeida, Macedo, Cardoso, Alves, Valencia, Arsequell, Planas and Saraiva (2004) Biochem. J. 381, 351-356], a protein implicated in familial amyloidotic polyneuropathy. In the present paper, the crystal structure of transthyretin complexed with this diflunisal derivative is reported, which enables a detailed analysis of the protein-ligand interactions. Iododiflunisal binds very deep in the hormone-binding channel. The iodine substituent is tightly anchored into a pocket of the binding site and the fluorine atoms provide extra hydrophobic contacts with the protein. The carboxylate substituent is involved in an electrostatic interaction with the N(zeta) of a lysine residue. Moreover, ligand-induced conformational alterations in the side chain of some residues result in the formation of new intersubunit hydrogen bonds. All these new interactions, induced by iododiflunisal, increase the stability of the tetramer impairing the formation of amyloid fibrils. The crystal structure of this complex opens perspectives for the design of more specific and effective drugs for familial amyloidotic polyneuropathy patients.
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Affiliation(s)
- Luís Gales
- *Instituto de Ciências Biomédicas Abel Salazar and Instituto de Biologia Molecular e Celular, Rua do Campo Alegre 823, 4150 Porto, Portugal
| | | | - Gemma Arsequell
- ‡CSIC, Instituto de Investigaciones Químicas y Ambientales, Barcelona, Spain
| | - Gregorio Valencia
- ‡CSIC, Instituto de Investigaciones Químicas y Ambientales, Barcelona, Spain
| | - Maria João Saraiva
- *Instituto de Ciências Biomédicas Abel Salazar and Instituto de Biologia Molecular e Celular, Rua do Campo Alegre 823, 4150 Porto, Portugal
| | - Ana Margarida Damas
- *Instituto de Ciências Biomédicas Abel Salazar and Instituto de Biologia Molecular e Celular, Rua do Campo Alegre 823, 4150 Porto, Portugal
- To whom correspondence should be addressed, at Instituto de Biologia Molecular e Celular (email )
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33
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Keetch CA, Bromley EHC, McCammon MG, Wang N, Christodoulou J, Robinson CV. L55P transthyretin accelerates subunit exchange and leads to rapid formation of hybrid tetramers. J Biol Chem 2005; 280:41667-74. [PMID: 16219761 DOI: 10.1074/jbc.m508753200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transthyretin is a tetrameric protein associated with the commonest form of systemic amyloid disease. Using isotopically labeled proteins and mass spectrometry, we compared subunit exchange in wild-type transthyretin with that of the variant associated with the most aggressive form of the disease, L55P. Wild-type subunit exchange occurs via both monomers and dimers, whereas exchange via dimers is the dominant mechanism for the L55P variant. Because patients with the L55P mutation are heterozygous, expressing both proteins simultaneously, we also analyzed the subunit exchange reaction between wild-type and L55P tetramers. We found that hybrid tetramers containing two or three L55P subunits dominate in the early stages of the reaction. Surprisingly, we also found that, in the presence of L55P transthyretin, the rate of dissociation of wild-type transthyretin is increased. This implies interactions between the two proteins that accelerate the formation of hybrid tetramers, a result with important implications for transthyretin amyloidosis.
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Affiliation(s)
- Catherine A Keetch
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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34
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Abstract
Copper-zinc superoxide dismutase (CuZnSOD, SOD1 protein) is an abundant copper- and zinc-containing protein that is present in the cytosol, nucleus, peroxisomes, and mitochondrial intermembrane space of human cells. Its primary function is to act as an antioxidant enzyme, lowering the steady-state concentration of superoxide, but when mutated, it can also cause disease. Over 100 different mutations have been identified in the sod1 genes of patients diagnosed with the familial form of amyotrophic lateral sclerosis (fALS). These mutations result in a highly diverse group of mutant proteins, some of them very similar to and others enormously different from wild-type SOD1. Despite their differences in properties, each member of this diverse set of mutant proteins causes the same clinical disease, presenting a challenge in formulating hypotheses as to what causes SOD1-associated fALS. In this review, we draw together and summarize information from many laboratories about the characteristics of the individual mutant SOD1 proteins in vivo and in vitro in the hope that it will aid investigators in their search for the cause(s) of SOD1-associated fALS.
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Affiliation(s)
- Joan Selverstone Valentine
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
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35
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Nelson R, Sawaya MR, Balbirnie M, Madsen AØ, Riekel C, Grothe R, Eisenberg D. Structure of the cross-beta spine of amyloid-like fibrils. Nature 2005; 435:773-8. [PMID: 15944695 PMCID: PMC1479801 DOI: 10.1038/nature03680] [Citation(s) in RCA: 1722] [Impact Index Per Article: 90.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Accepted: 04/25/2005] [Indexed: 11/09/2022]
Abstract
Numerous soluble proteins convert to insoluble amyloid-like fibrils that have common properties. Amyloid fibrils are associated with fatal diseases such as Alzheimer's, and amyloid-like fibrils can be formed in vitro. For the yeast protein Sup35, conversion to amyloid-like fibrils is associated with a transmissible infection akin to that caused by mammalian prions. A seven-residue peptide segment from Sup35 forms amyloid-like fibrils and closely related microcrystals, from which we have determined the atomic structure of the cross-beta spine. It is a double beta-sheet, with each sheet formed from parallel segments stacked in register. Side chains protruding from the two sheets form a dry, tightly self-complementing steric zipper, bonding the sheets. Within each sheet, every segment is bound to its two neighbouring segments through stacks of both backbone and side-chain hydrogen bonds. The structure illuminates the stability of amyloid fibrils, their self-seeding characteristic and their tendency to form polymorphic structures.
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Affiliation(s)
- Rebecca Nelson
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Box 951570, UCLA, Los Angeles CA 90095-1570
| | - Michael R. Sawaya
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Box 951570, UCLA, Los Angeles CA 90095-1570
| | - Melinda Balbirnie
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Box 951570, UCLA, Los Angeles CA 90095-1570
| | - Anders Ø. Madsen
- Centre for Crystallographic Studies, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 KBH, Denmark
- ESRF, B.P. 220 F-38043 Grenoble Cedex, France
| | | | - Robert Grothe
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Box 951570, UCLA, Los Angeles CA 90095-1570
| | - David Eisenberg
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Box 951570, UCLA, Los Angeles CA 90095-1570
- Correspondence and requests for materials should be addressed to D.E. (). The structures of GNNQQNY and NNQQNY have been deposited in the Protein Data Bank with accession codes 1yjp and 1yjo, respectively
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36
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Yang M, Lei M, Bruschweiler R, Huo S. Initial conformational changes of human transthyretin under partially denaturing conditions. Biophys J 2005; 89:433-43. [PMID: 15821170 PMCID: PMC1366544 DOI: 10.1529/biophysj.105.059642] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human transthyretin (TTR) is an amyloidogenic protein. The pathway of TTR amyloid formation has been proposed based on lines of evidence: TTR tetramer first dissociates into native monomers, which is shown to be a rate-limiting step in the formation of fibrils. Subsequently, the monomeric species partially unfold to form the aggregation intermediates. Once such intermediates are formed, the following self-assembly process is a downhill polymerization. Hence, tertiary structural changes within the monomers after the dissociation are essential for the amyloid formation. These tertiary structural changes can be facilitated by partial denaturation. To probe the conformational changes under the partially denaturing conditions, five independent trajectories were collected for the wild-type (WT) and its pathogenic variants at 300 and 350 K, resulting in simulations that totaled 59 ns. Under these conditions, L55P variant is more labile than the wild-type and V30M variant. We have observed that the D strand of WT-TTR is trapped in two local minima: the native conformation and the amyloidogenic fold that resembles the surface loop of residues 54-55 of L55P variant. In the tetrameric state, the F strand is bent with large separations at the F-F' interface. This strand becomes flatter in the monomeric state, which may facilitate the formation of new F-F' interface with possible prolonged hydrogen bonds and/or shift in beta-strand register in the fibril state. During the unfolding process, the anticorrelated motion between the strands H and G as well as the strands H and A pulls the H strand out of the inner sheet plane, leading to a more twisted inner sheet. Our simulation has provided important detailed structural information about the partially unfolded state of TTR that may be related to the amyloidogenic intermediates.
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Affiliation(s)
- Mingfeng Yang
- Gustaf H. Carlson School of Chemistry and Biochemistry, Clark University, Worcester, Massachusetts 01610, USA
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37
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Zandomeneghi G, Krebs MRH, McCammon MG, Fändrich M. FTIR reveals structural differences between native beta-sheet proteins and amyloid fibrils. Protein Sci 2004; 13:3314-21. [PMID: 15537750 PMCID: PMC2287307 DOI: 10.1110/ps.041024904] [Citation(s) in RCA: 523] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The presence of beta-sheets in the core of amyloid fibrils raised questions as to whether or not beta-sheet-containing proteins, such as transthyretin, are predisposed to form such fibrils. However, we show here that the molecular structure of amyloid fibrils differs more generally from the beta-sheets in native proteins. This difference is evident from the amide I region of the infrared spectrum and relates to the distribution of the phi/psi dihedral angles within the Ramachandran plot, the average number of strands per sheet, and possibly, the beta-sheet twist. These data imply that amyloid fibril formation from native beta-sheet proteins can involve a substantial structural reorganization.
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38
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Jayasinghe SA, Langen R. Identifying structural features of fibrillar islet amyloid polypeptide using site-directed spin labeling. J Biol Chem 2004; 279:48420-5. [PMID: 15358791 DOI: 10.1074/jbc.m406853200] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Pancreatic amyloid deposits, composed primarily of the 37-residue islet amyloid polypeptide (IAPP), are a characteristic feature found in more than 90% of patients with type II diabetes. Although IAPP amyloid deposits are associated with areas of pancreatic islet beta-cell dysfunction and depletion and are thought to play a role in disease, their structure is unknown. We used electron paramagnetic resonance spectroscopy to analyze eight spin-labeled derivatives of IAPP in an effort to determine structural features of the peptide. In solution, all eight derivatives gave rise to electron paramagnetic resonance spectra with sharp lines indicative of rapid motion on the sub-nanosecond time scale. These spectra are consistent with a rapidly tumbling and highly dynamic peptide. In contrast, spectra for the fibrillar form exhibit reduced mobility and the presence of strong intermolecular spin-spin interactions. The latter implies that the peptide subunits are ordered and that the same residues from neighboring peptides are in close proximity to one another. Our data are consistent with a parallel arrangement of IAPP peptides within the amyloid fibril. Analysis of spin label mobility indicates a high degree of order throughout the peptide, although the N-terminal region is slightly less ordered. Possible similarities with respect to the domain organization and parallelism of Alzheimer's amyloid beta peptide fibrils are discussed.
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Affiliation(s)
- Sajith A Jayasinghe
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California 90033, USA
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39
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Hörnberg A, Olofsson A, Eneqvist T, Lundgren E, Sauer-Eriksson AE. The β-strand D of transthyretin trapped in two discrete conformations. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1700:93-104. [PMID: 15210129 DOI: 10.1016/j.bbapap.2004.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2004] [Revised: 03/30/2004] [Accepted: 04/06/2004] [Indexed: 11/15/2022]
Abstract
Conformational changes in native and variant forms of the human plasma protein transthyretin (TTR) induce several types of amyloid diseases. Biochemical and structural studies have mapped the initiation site of amyloid formation onto residues at the outer C and D beta-strands and their connecting loop. In this study, we characterise an engineered variant of transthyretin, Ala108Tyr/Leu110Glu, which is kinetically and thermodynamically more stable than wild-type transthyretin, and as a consequence less amyloidogenic. Crystal structures of the mutant were determined in two space groups, P2(1)2(1)2 and C2, from crystals grown in the same crystallisation set-up. The structures are identical with the exception for residues Leu55-Leu58, situated at beta-strand D and the following DE loop. In particular, residues Leu55-His56 display large shifts in the C2 structure. There the direct hydrogen bonding between beta-strands D and A has been disrupted and is absent, whereas the beta-strand D is present in the P2(1)2(1)2 structure. This difference shows that from a mixture of metastable TTR molecules, only the molecules with an intact beta-strand D are selected for crystal growth in space group P2(1)2(1)2. The packing of TTR molecules in the C2 crystal form and in the previously determined amyloid TTR (ATTR) Leu55Pro crystal structure is close-to-identical. This packing arrangement is therefore not unique in amyloidogenic mutants of TTR.
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Affiliation(s)
- Andreas Hörnberg
- Umeå Centre for Molecular Pathogenesis, Umeå University, SE-901 87 Umeå, Sweden
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40
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Dzwolak W, Smirnovas V, Jansen R, Winter R. Insulin forms amyloid in a strain-dependent manner: an FT-IR spectroscopic study. Protein Sci 2004; 13:1927-32. [PMID: 15169954 PMCID: PMC2279922 DOI: 10.1110/ps.03607204] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The presence of 20% (v/v) ethanol triggers growth of insulin amyloid with distinct infrared spectroscopic features, compared with the fibrils obtained under ambient conditions. Here we report that the two insulin amyloid types behave in the prion strain-like manner regarding seeding specificity and ability of the self-propagating conformational template to overrule unfavorable environmental factors and maintain the initial folding pattern. The type of the original seed has been shown to prevail over cosolvent effects and determines spectral position and width of the amide I' infrared band of the heterogeneously seeded amyloid. These findings imply that "strains" may be a common generic trait of amyloids.
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Affiliation(s)
- Wojciech Dzwolak
- High Pressure Research Center, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland.
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41
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Siepen JA, Radford SE, Westhead DR. Beta edge strands in protein structure prediction and aggregation. Protein Sci 2004; 12:2348-59. [PMID: 14500893 PMCID: PMC2366916 DOI: 10.1110/ps.03234503] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
It is well established that recognition between exposed edges of beta-sheets is an important mode of protein-protein interaction and can have pathological consequences; for instance, it has been linked to the aggregation of proteins into a fibrillar structure, which is associated with a number of predominantly neurodegenerative disorders. A number of protective mechanisms have evolved in the edge strands of beta-sheets, preventing the aggregation and insolubility of most natural beta-sheet proteins. Such mechanisms are unfavorable in the interior of a beta-sheet. The problem of distinguishing edge strands from central strands based on sequence information alone is important in predicting residues and mutations likely to be involved in aggregation, and is also a first step in predicting folding topology. Here we report support vector machine (SVM) and decision tree methods developed to classify edge strands from central strands in a representative set of protein domains. Interestingly, rules generated by the decision tree method are in close agreement with our knowledge of protein structure and are potentially useful in a number of different biological applications. When trained on strands from proteins of known structure, using structure-based (Dictionary of Secondary Structure in Proteins) strand assignments, both methods achieved mean cross-validated, prediction accuracies of approximately 78%. These accuracies were reduced when strand assignments from secondary structure prediction were used. Further investigation of this effect revealed that it could be explained by a significant reduction in the accuracy of standard secondary structure prediction methods for edge strands, in comparison with central strands.
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Affiliation(s)
- Jennifer A Siepen
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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42
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Olofsson A, Ippel JH, Wijmenga SS, Lundgren E, Ohman A. Probing Solvent Accessibility of Transthyretin Amyloid by Solution NMR Spectroscopy. J Biol Chem 2004; 279:5699-707. [PMID: 14604984 DOI: 10.1074/jbc.m310605200] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human plasma protein transthyretin (TTR) may form fibrillar protein deposits that are associated with both inherited and idiopathic amyloidosis. The present study utilizes solution nuclear magnetic resonance spectroscopy, in combination with hydrogen/deuterium exchange, to determine residue-specific solvent protection factors within the fibrillar structure of the clinically relevant variant, TTRY114C. This novel approach suggests a fibril core comprised of the six beta-strands, A-B-E-F-G-H, which retains a native-like conformation. Strands C and D are dislocated from their native edge region and become solvent-exposed, leaving a new interface involving strands A and B open for intermolecular interactions. Our results further support a native-like intermolecular association between strands F-F' and H-H' with a prolongation of these beta-strands and, interestingly, with a possible shift in beta-strand register of the subunit assembly. This finding may explain previous observations of a monomeric intermediate preceding fibril formation. A structural model based on our results is presented.
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Affiliation(s)
- Anders Olofsson
- Department of Molecular Biology, Umeå University, Umeå SE-901 87, Sweden
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43
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Abstract
The problem of determining and understanding the molecular structures of amyloid fibrils has attracted considerable attention and effort over the past several years. Although complete, high-resolution structures have not yet been obtained, key features of protein and peptide conformations and supramolecular organization within amyloid fibrils have been elucidated using a variety of novel experimental methods, including magnetic resonance spectroscopies, electron microscopy, X-ray and neutron scattering, and biochemical techniques. The experimental data are beginning to shed light on issues such as the nature of the intermolecular interactions that stabilize amyloid structures, the molecular structural basis for polymorphism in amyloid fibrils, the universality of amyloid structures, and the balance between structural order and disorder within amyloid fibrils. Recent structural data will contribute to an improved understanding of the mechanisms of amyloid formation and to the development of therapeutic agents for amyloid diseases.
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Affiliation(s)
- Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Building 5, Room 112, National Institutes of Health, Bethesda, MD 20892-0520, USA.
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44
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Dzwolak W, Muraki T, Kato M, Taniguchi Y. Chain-length dependence of ?-helix to ?-sheet transition in polylysine: Model of protein aggregation studied by temperature-tuned FTIR spectroscopy. Biopolymers 2004; 73:463-9. [PMID: 14991664 DOI: 10.1002/bip.10582] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The chain-length dependence of the alpha-helix to beta-sheet transition in poly(L-lysine) is studied by temperature-tuned FTIR spectroscopy. This study shows that heterogeneous samples of poly(L-lysine), comprising polypeptide chains with various lengths, undergo the alpha-beta transition at an intermediate temperature compared to homogeneous ingredients. This holds true as long as each individual fraction of the polypeptide is capable of adopting an antiparallel beta-sheet structure. The tendency is that the longer chain is, the lower the alpha-beta transition temperature is, which has been linked to the presence of distorted or solvated helices with turns or beta sheets in elongating chains of poly(L-lysine). As such helical structures are apparently conducive to the alpha-beta transition, this draws a comparison to the hypothesis of metastable protein conformational states being a common stage in amyloid-formation pathways. The antiparallel architecture of the beta sheet is likely to reflect the pretransition interhelical interactions in poly(L-lysine). Namely, the chains are arranged in an antiparallel manner because of energetically favored antiparallel pre-assembly of dipolar alpha helices.
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Affiliation(s)
- Wojciech Dzwolak
- High Pressure Research Center, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland
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45
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Der-Sarkissian A, Jao CC, Chen J, Langen R. Structural organization of alpha-synuclein fibrils studied by site-directed spin labeling. J Biol Chem 2003; 278:37530-5. [PMID: 12815044 DOI: 10.1074/jbc.m305266200] [Citation(s) in RCA: 289] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite its importance in Parkinson's disease, a detailed understanding of the structure and mechanism of alpha-synuclein fibril formation remains elusive. In this study, we used site-directed spin labeling and electron paramagnetic resonance spectroscopy to study the structural features of monomeric and fibrillar alpha-synuclein. Our results indicate that monomeric alpha-synuclein, in solution, has a highly dynamic structure, in agreement with the notion that alpha-synuclein is a natively unfolded protein. In contrast, fibrillar aggregates of alpha-synuclein exhibit a distinct domain organization. Our data identify a highly ordered and specifically folded central core region of approximately 70 amino acids, whereas the N terminus is structurally more heterogeneous and the C terminus ( approximately 40 amino acids) is completely unfolded. Interestingly, the central core region of alpha-synuclein exhibits several features reminiscent of those observed in the core region of fibrillar Alzheimer's amyloid beta peptide, including an in-register parallel structure. Although the lengths of the respective core regions differ, fibrils from different amyloid proteins nevertheless appear to be able to take up highly similar, and possibly conserved, structures.
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Affiliation(s)
- Ani Der-Sarkissian
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles 90089, USA
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46
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Fay N, Inoue Y, Bousset L, Taguchi H, Melki R. Assembly of the yeast prion Ure2p into protein fibrils. Thermodynamic and kinetic characterization. J Biol Chem 2003; 278:30199-205. [PMID: 12777380 DOI: 10.1074/jbc.m303000200] [Citation(s) in RCA: 32] [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
The [URE3] phenotype in Saccharomyces cerevisiae propagates by a prion mechanism, involving the aggregation of the normally soluble and highly helical protein Ure2. Previous data have shown that the protein spontaneously forms in vitro long, straight, insoluble fibrils at neutral pH that are similar to amyloids in that they bind Congo red and show green-yellow birefringence and have an increased resistance to proteolysis. These fibrils are not amyloids as they are devoid of a cross-beta core. Here we further document the mechanism of assembly of Ure2p into fibrils. The critical concentration for Ure2p assembly is measured, and the minimal size of the nuclei that are the precursors of Ure2p fibrils is determined. Our data indicate that the assembly process is irreversible. As a consequence, the critical concentration is very low. By analyzing the elongation rates of preformed fibrils and combining the results with single-fiber imaging experiments of a variant Ure2p labeled by fluorescent dyes, we reveal the polarity of the fibrils and differences in the elongation rates at their ends. These results bring novel insight in the process of Ure2p assembly into fibrils and the mechanism of propagation of yeast prions.
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Affiliation(s)
- Nicolas Fay
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, 91198 Gif-sur-Yvette Cedex, France
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47
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Ferrão-Gonzales AD, Palmieri L, Valory M, Silva JL, Lashuel H, Kelly JW, Foguel D. Hydration and packing are crucial to amyloidogenesis as revealed by pressure studies on transthyretin variants that either protect or worsen amyloid disease. J Mol Biol 2003; 328:963-74. [PMID: 12729768 DOI: 10.1016/s0022-2836(03)00368-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The formation of amyloid aggregates is the hallmark of the amyloidogenic diseases. Transthyretin (TTR) is involved in senile systemic amyloidosis (wild-type protein) and familial amyloidotic polyneuropathy (point mutants). Through the use of high hydrostatic pressure (HHP), we compare the stability among wild-type (wt) TTR, two disease-associated mutations (V30M and L55P) and a trans-suppressor mutation (T119M). Our data show that the amyloidogenic conformation, easily populated in the disease-associated mutant L55P, can be induced by a cycle of compression-decompression with the wt protein rendering the latter highly amyloidogenic. After decompression, the recovered wt structure has weaker subunit interactions (loosened tetramer, T(4)(*)) and presents a stability similar to L55P, suggesting that HHP induces a defective fold in the wt protein, converting it to an altered conformation already present in the aggressive mutant, L55P. On the other hand, glucose, a chemical chaperone, can mimic the trans-suppression mutation by stabilizing the native state and by decreasing the amyloidogenic potential of the wt TTR at pH 5.0. The sequence of pressure stability observed was: L55P<V30M<wt<<T119M. The pressure dissociation of L55P at 1 degrees C exhibited dependence on protein concentration, allowing us to assess the volume change of association and the free-energy change. After a cycle of compression-decompression at 37 degrees C and pH 5.6 or lower, all amyloidogenic variants underwent aggregation. Binding of bis-(8-anilinonaphthalene-1-sulfonate) (bis-ANS) revealed that the species formed under pressure retained part of its tertiary contacts (except T119M). However, at neutral pH, where aggregation did not take place after decompression, bis-ANS binding was absent. Thus, TTR has to experience this partially folded conformation to undergo aggregation after decompression. Overall, our studies provide evidence that amyloidogenesis correlates with less packed structures (larger volume changes) and high susceptibility to water infiltration. The hydration effects can be counteracted by osmolytes or by a specific mutation.
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Affiliation(s)
- Astria D Ferrão-Gonzales
- Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Gales L, Cardoso I, Fayard B, Quintanilha A, Saraiva MJ, Damas AM. X-ray absorption spectroscopy reveals a substantial increase of sulfur oxidation in transthyretin (TTR) upon fibrillization. J Biol Chem 2003; 278:11654-60. [PMID: 12538647 DOI: 10.1074/jbc.m210798200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transthyretin (TTR) amyloid fibrils are the main component of the amyloid deposits occurring in Familial Amyloidotic Polyneuropathy patients. This is 1 of 20 human proteins leading to protein aggregation disorders such as Alzheimer's and Creutzfeldt-Jakob diseases. The structural details concerning the association of the protein molecules are essential for a better understanding of the disease and consequently the design of new strategies for diagnosis and therapeutics. Disulfide bonds are frequently considered essential for the stability of protein aggregates and since in the TTR monomers there is one cysteine residue, it is important to determine unambiguously the redox state of sulfur present in the fibrils. In this work we used x-ray spectroscopy to further characterize TTR amyloid fibrils. The sulfur K-edge absorption spectra for the wild type and some amyloidogenic TTR variants in the soluble and fibrillar forms were analyzed. Whereas in the soluble proteins the thiol group from cysteine (R-SH) and the thioether group from methionine (R-S-CH(3)) are the most abundant forms, in the TTR fibrils there is a significant oxidation of sulfur to the sulfonate form in the cysteine residue and a partial oxidation of sulfur to sulfoxide in the methionine residues. Further interpretation of the data reveals that there are no disulfide bridges in the fibrillar samples and suggest conformational changes in the TTR molecule, namely in strand A and/or in its vicinity, upon fibril formation.
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Affiliation(s)
- Luís Gales
- ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Largo Prof. Abel Salazar n 2, 4099-003 Porto, Portugal
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Török M, Milton S, Kayed R, Wu P, McIntire T, Glabe CG, Langen R. Structural and dynamic features of Alzheimer's Abeta peptide in amyloid fibrils studied by site-directed spin labeling. J Biol Chem 2002; 277:40810-5. [PMID: 12181315 DOI: 10.1074/jbc.m205659200] [Citation(s) in RCA: 333] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Electron paramagnetic resonance spectroscopy analysis of 19 spin-labeled derivatives of the Alzheimer's amyloid beta (Abeta) peptide was used to reveal structural features of amyloid fibril formation. In the fibril, extensive regions of the peptide show an in-register, parallel arrangement. Based on the parallel arrangement and side chain mobility analysis we find the amyloid structure to be mostly ordered and specific, but we also identify more dynamic regions (N and C termini) and likely turn or bend regions (around residues 23-26). Despite their different aggregation properties and roles in disease, the two peptides, Abeta40 and Abeta42, homogeneously co-mix in amyloid fibrils suggesting that they possess the same structural architecture.
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Affiliation(s)
- Marianna Török
- Department of Biochemistry and Molecular Biology, Neurogenetic Institute and Arnold and Mabel Beckman Macular Research Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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Cardoso I, Goldsbury CS, Müller SA, Olivieri V, Wirtz S, Damas AM, Aebi U, Saraiva MJ. Transthyretin fibrillogenesis entails the assembly of monomers: a molecular model for in vitro assembled transthyretin amyloid-like fibrils. J Mol Biol 2002; 317:683-95. [PMID: 11955017 DOI: 10.1006/jmbi.2002.5441] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Extracellular accumulation of transthyretin (TTR) variants in the form of fibrillar amyloid deposits is the pathological hallmark of familial amyloidotic polyneuropathy (FAP). The TTR Leu55Pro variant occurs in the most aggressive forms of this disease. Inhibition of TTR wild-type (WT) and particularly TTR Leu55Pro fibril formation is of interest as a potential therapeutic strategy and requires a thorough understanding of the fibril assembly mechanism. To this end, we report on the in vitro assembly properties as observed by transmission electron microscopy (TEM), atomic force microscopy (AFM) and quantitative scanning transmission electron microscopy (STEM) for both TTR WT fibrils produced by acidification, and TTR Leu55Pro fibrils assembled at physiological pH. The morphological features and dimensions of TTR WT and TTR Leu55Pro fibrils were similar, with up to 300 nm long, 8 nm wide fibrils being the most prominent species in both cases. Other species were evident; 4-5 nm wide fibrils, 9-10 nm wide fibrils and oligomers of various sizes. STEM mass-per-length (MPL) measurements revealed discrete fibril types with masses of 9.5 and 14.0(+/-1.4) KDa/nm for TTR WT fibrils and 13.7, 18.5 and 23.2(+/-1.5) kDa/nm for TTR Leu55Pro fibrils. These MPL values are consistent with a model in which fibrillar TTR structures are composed of two, three, four or five elementary protofilaments, with each protofilament being a vertical stack of structurally modified TTR monomers assembled with the 2.9 nm axial monomer-monomer spacing indicated by X-ray fibre diffraction data. Ex vivo TTR amyloid fibrils were examined. From their morphological appearance compared to these, the in vitro assembled TTR WT and Leu55Pro fibrils examined may represent immature fibrillar species. The in vitro system operating at physiological pH for TTR Leu55Pro and the model presented for the molecular arrangement of TTR monomers within fibrils may, therefore, describe early fibril assembly events in vivo.
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Affiliation(s)
- I Cardoso
- Amyloid Unit, Instistute for Molecular and Cell Biology, Porto University, Porto, Portugal
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