1
|
Abramov-Harpaz K, Lan-Mark S, Miller Y. Structural packing of the non-amyloid component core domain in α-synuclein plays a role in the stability of the fibrils. Biophys Chem 2024; 310:107239. [PMID: 38663121 DOI: 10.1016/j.bpc.2024.107239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 04/08/2024] [Accepted: 04/14/2024] [Indexed: 05/23/2024]
Abstract
Parkinson's disease (PD) is one of many neurodegenerative diseases. The protein associated with PD is α-synuclein (AS). Aggregation of AS protein into oligomers, protofilaments, and finally to fibrils yields to the development of PD. The aggregation process of AS leads to the formation of polymorphic AS fibrils. Herein, we compared four polymorphic full-length AS1-140 fibrils, using extensive computational tools. The main conclusion of this study emphasizes the role of the structurally packed non-amyloid component (NAC) core domain in AS fibrils. Polymorphic AS fibrils that presented a packed NAC core domain, exhibited more β-sheets and fewer fluctuations in the NAC domain. Hence, these AS fibrils are more stable and populated than the AS fibrils, by which the NAC domains are more exposed, more fluctuate and less packed in the fibrillary structure. Therefore, this study emphasizes the importance of the NAC domain packing in the morphology of AS fibrils. The results obtained in this study will initiate future studies to develop compounds to prevent and inhibit AS aggregation.
Collapse
Affiliation(s)
- Karina Abramov-Harpaz
- Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Be'er Sheva 8410501, Israel; Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beér-Sheva, 8410501, Israel; The School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, Beér-Sheva, 8410501, Israel
| | - Sapir Lan-Mark
- Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Be'er Sheva 8410501, Israel; Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beér-Sheva, 8410501, Israel; The School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, Beér-Sheva, 8410501, Israel
| | - Yifat Miller
- Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Be'er Sheva 8410501, Israel; Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beér-Sheva, 8410501, Israel; The School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, Beér-Sheva, 8410501, Israel.
| |
Collapse
|
2
|
Thurber KR, Yau WM, Tycko R. Structure of Amyloid Peptide Ribbons Characterized by Electron Microscopy, Atomic Force Microscopy, and Solid-State Nuclear Magnetic Resonance. J Phys Chem B 2024; 128:1711-1723. [PMID: 38348474 DOI: 10.1021/acs.jpcb.3c07867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Polypeptides often self-assemble to form amyloid fibrils, which contain cross-β structural motifs and are typically 5-15 nm in width and micrometers in length. In many cases, short segments of longer amyloid-forming protein or peptide sequences also form cross-β assemblies but with distinctive ribbon-like morphologies that are characterized by a well-defined thickness (on the order of 5 nm) in one lateral dimension and a variable width (typically 10-100 nm) in the other. Here, we use a novel combination of data from solid-state nuclear magnetic resonance (ssNMR), dark-field transmission electron microscopy (TEM), atomic force microscopy (AFM), and cryogenic electron microscopy (cryoEM) to investigate the structures within amyloid ribbons formed by residues 14-23 and residues 11-25 of the Alzheimer's disease-associated amyloid-β peptide (Aβ14-23 and Aβ11-25). The ssNMR data indicate antiparallel β-sheets with specific registries of intermolecular hydrogen bonds. Mass-per-area values are derived from dark-field TEM data. The ribbon thickness is determined from AFM images. For Aβ14-23 ribbons, averaged cryoEM images show a periodic spacing of β-sheets. The combined data support structures in which the amyloid ribbon growth direction is the direction of intermolecular hydrogen bonds between β-strands, the ribbon thickness corresponds to the width of one β-sheet (i.e., approximately the length of one molecule), and the variable ribbon width is a variable multiple of the thickness of one β-sheet (i.e., a multiple of the repeat distance in a stack of β-sheets). This architecture for a cross-β assembly may generally exist within amyloid ribbons.
Collapse
Affiliation(s)
- Kent R Thurber
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| |
Collapse
|
3
|
Phyo P, Zhao X, Templeton AC, Xu W, Cheung JK, Su Y. Understanding molecular mechanisms of biologics drug delivery and stability from NMR spectroscopy. Adv Drug Deliv Rev 2021; 174:1-29. [PMID: 33609600 DOI: 10.1016/j.addr.2021.02.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/20/2021] [Accepted: 02/07/2021] [Indexed: 02/06/2023]
Abstract
Protein therapeutics carry inherent limitations of membrane impermeability and structural instability, despite their predominant role in the modern pharmaceutical market. Effective formulations are needed to overcome physiological and physicochemical barriers, respectively, for improving bioavailability and stability. Knowledge of membrane affinity, cellular internalization, encapsulation, and release of drug-loaded carrier vehicles uncover the structural basis for designing and optimizing biopharmaceuticals with enhanced delivery efficiency and therapeutic efficacy. Understanding stabilizing and destabilizing interactions between protein drugs and formulation excipients provide fundamental mechanisms for ensuring the stability and quality of biological products. This article reviews the molecular studies of biologics using solution and solid-state NMR spectroscopy on structural attributes pivotal to drug delivery and stability. In-depth investigation of the structure-function relationship of drug delivery systems based on cell-penetrating peptides, lipid nanoparticles and polymeric colloidal, and biophysical and biochemical stability of peptide, protein, monoclonal antibody, and vaccine, as the integrative efforts on drug product design, will be elaborated.
Collapse
Affiliation(s)
- Pyae Phyo
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Xi Zhao
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Allen C Templeton
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Wei Xu
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Jason K Cheung
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Yongchao Su
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States.
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Xu L, Bhattacharya S, Thompson D. The fold preference and thermodynamic stability of α-synuclein fibrils is encoded in the non-amyloid-β component region. Phys Chem Chem Phys 2018; 20:4502-4512. [DOI: 10.1039/c7cp08321a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The strain-dependent synucleinopathies may be partially imprinted in the fold-dependent thermodynamic properties of non-amyloid-β component (NAC) fibrils.
Collapse
Affiliation(s)
- Liang Xu
- Department of Physics
- Bernal Institute
- University of Limerick
- Ireland
| | | | - Damien Thompson
- Department of Physics
- Bernal Institute
- University of Limerick
- Ireland
| |
Collapse
|
6
|
Silvers R, Colvin MT, Frederick KK, Jacavone AC, Lindquist S, Linse S, Griffin RG. Aggregation and Fibril Structure of Aβ M01-42 and Aβ 1-42. Biochemistry 2017; 56:4850-4859. [PMID: 28792214 PMCID: PMC8254419 DOI: 10.1021/acs.biochem.7b00729] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A mechanistic understanding of Aβ aggregation and high-resolution structures of Aβ fibrils and oligomers are vital to elucidating relevant details of neurodegeneration in Alzheimer's disease, which will facilitate the rational design of diagnostic and therapeutic protocols. The most detailed and reproducible insights into structure and kinetics have been achieved using Aβ peptides produced by recombinant expression, which results in an additional methionine at the N-terminus. While the length of the C-terminus is well established to have a profound impact on the peptide's aggregation propensity, structure, and neurotoxicity, the impact of the N-terminal methionine on the aggregation pathways and structure is unclear. For this reason, we have developed a protocol to produce recombinant Aβ1-42, sans the N-terminal methionine, using an N-terminal small ubiquitin-like modifier-Aβ1-42 fusion protein in reasonable yield, with which we compared aggregation kinetics with AβM01-42 containing the additional methionine residue. The data revealed that Aβ1-42 and AβM01-42 aggregate with similar rates and by the same mechanism, in which the generation of new aggregates is dominated by secondary nucleation of monomers on the surface of fibrils. We also recorded magic angle spinning nuclear magnetic resonance spectra that demonstrated that excellent spectral resolution is maintained with both AβM01-42 and Aβ1-42 and that the chemical shifts are virtually identical in dipolar recoupling experiments that provide information about rigid residues. Collectively, these results indicate that the structure of the fibril core is unaffected by N-terminal methionine. This is consistent with the recent structures of AβM01-42 in which M0 is located at the terminus of a disordered 14-amino acid N-terminal tail.
Collapse
Affiliation(s)
- Robert Silvers
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Michael T Colvin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Kendra K Frederick
- Whitehead Institute for Biomedical Research , Nine Cambridge Center, Cambridge, Massachusetts 02142, United States
| | - Angela C Jacavone
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Susan Lindquist
- Whitehead Institute for Biomedical Research , Nine Cambridge Center, Cambridge, Massachusetts 02142, United States
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Lund University , SE22100 Lund, Sweden
| | - Robert G Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| |
Collapse
|
7
|
Wang T, Jo H, DeGrado WF, Hong M. Water Distribution, Dynamics, and Interactions with Alzheimer's β-Amyloid Fibrils Investigated by Solid-State NMR. J Am Chem Soc 2017; 139:6242-6252. [PMID: 28406028 PMCID: PMC5808936 DOI: 10.1021/jacs.7b02089] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Water is essential for protein folding and assembly of amyloid fibrils. Internal water cavities have been proposed for several amyloid fibrils, but no direct structural and dynamical data have been reported on the water dynamics and site-specific interactions of water with the fibrils. Here we use solid-state NMR spectroscopy to investigate the water interactions of several Aβ40 fibrils. 1H spectral lineshapes, T2 relaxation times, and two-dimensional (2D) 1H-13C correlation spectra show that there are five distinct water pools: three are peptide-bound water, while two are highly dynamic water that can be assigned to interfibrillar water and bulk-like matrix water. All these water pools are associated with the fibrils on the nanometer scale. Water-transferred 2D correlation spectra allow us to map out residue-specific hydration and give evidence for the presence of a water pore in the center of the three-fold symmetric wild-type Aβ40 fibril. In comparison, the loop residues and the intramolecular strand-strand interface have low hydration, excluding the presence of significant water cavities in these regions. The Osaka Aβ40 mutant shows lower hydration and more immobilized water than wild-type Aβ40, indicating the influence of peptide structure on the dynamics and distribution of hydration water. Finally, the highly mobile interfibrillar and matrix water exchange with each other on the time scale of seconds, suggesting that fibril bundling separates these two water pools, and water molecules must diffuse along the fibril axis before exchanging between these two environments. These results provide insights and experimental constraints on the spatial distribution and dynamics of water pools in these amyloid fibrils.
Collapse
Affiliation(s)
- Tuo Wang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry and Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California 94143, United States
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry and Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California 94143, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
8
|
Mandal A, Boatz JC, Wheeler TB, van der Wel PCA. On the use of ultracentrifugal devices for routine sample preparation in biomolecular magic-angle-spinning NMR. JOURNAL OF BIOMOLECULAR NMR 2017; 67:165-178. [PMID: 28229262 PMCID: PMC5445385 DOI: 10.1007/s10858-017-0089-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/19/2017] [Indexed: 05/07/2023]
Abstract
A number of recent advances in the field of magic-angle-spinning (MAS) solid-state NMR have enabled its application to a range of biological systems of ever increasing complexity. To retain biological relevance, these samples are increasingly studied in a hydrated state. At the same time, experimental feasibility requires the sample preparation process to attain a high sample concentration within the final MAS rotor. We discuss these considerations, and how they have led to a number of different approaches to MAS NMR sample preparation. We describe our experience of how custom-made (or commercially available) ultracentrifugal devices can facilitate a simple, fast and reliable sample preparation process. A number of groups have since adopted such tools, in some cases to prepare samples for sedimentation-style MAS NMR experiments. Here we argue for a more widespread adoption of their use for routine MAS NMR sample preparation.
Collapse
Affiliation(s)
- Abhishek Mandal
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Jennifer C Boatz
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Travis B Wheeler
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15260, USA
| | - Patrick C A van der Wel
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA.
| |
Collapse
|
9
|
Structural basis for the dissociation of α-synuclein fibrils triggered by pressure perturbation of the hydrophobic core. Sci Rep 2016; 6:37990. [PMID: 27901101 PMCID: PMC5128797 DOI: 10.1038/srep37990] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/04/2016] [Indexed: 12/18/2022] Open
Abstract
Parkinson’s disease is a neurological disease in which aggregated forms of the α-synuclein (α-syn) protein are found. We used high hydrostatic pressure (HHP) coupled with NMR spectroscopy to study the dissociation of α-syn fibril into monomers and evaluate their structural and dynamic properties. Different dynamic properties in the non-amyloid-β component (NAC), which constitutes the Greek-key hydrophobic core, and in the acidic C-terminal region of the protein were identified by HHP NMR spectroscopy. In addition, solid-state NMR revealed subtle differences in the HHP-disturbed fibril core, providing clues to how these species contribute to seeding α-syn aggregation. These findings show how pressure can populate so far undetected α-syn species, and they lay out a roadmap for fibril dissociation via pathways not previously observed using other approaches. Pressure perturbs the cavity-prone hydrophobic core of the fibrils by pushing water inward, thereby inducing the dissociation into monomers. Our study offers the molecular details of how hydrophobic interaction and the formation of water-excluded cavities jointly contribute to the assembly and stabilization of the fibrils. Understanding the molecular forces behind the formation of pathogenic fibrils uncovered by pressure perturbation will aid in the development of new therapeutics against Parkinson’s disease.
Collapse
|
10
|
Challenges in studying the structures of metal-amyloid oligomers related to type 2 diabetes, Parkinson's disease, and Alzheimer's disease. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.04.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
11
|
Xu L, Nussinov R, Ma B. Coupling of the non-amyloid-component (NAC) domain and the KTK(E/Q)GV repeats stabilize the α-synuclein fibrils. Eur J Med Chem 2016; 121:841-850. [PMID: 26873872 PMCID: PMC4960003 DOI: 10.1016/j.ejmech.2016.01.044] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 01/15/2016] [Accepted: 01/22/2016] [Indexed: 12/11/2022]
Abstract
The aggregates of α-synuclein (αS) are a major pathological hallmark of Parkinson's disease (PD) making their structure-function relationship important for rational drug design. Yet, the atomic structure of the αS aggregates is unavailable, making it difficult to understand the underlying aggregation mechanism. In this work, based on available experimental data, we examined plausible molecular structures of αS(20/30-110) fibrils for the first time by employing computational approaches. The optimized structure was used to investigate possible interactions with aggregation inhibitors. Our structural models characterize the essential properties of the five-layered fold of the αS fibril. The distribution of the β-strands and the topology of the five β-strands in the relatively stable models are in good agreement with experimental values. In particular, we find that the KTK(E/Q)GV repeat motifs significantly stabilize the αS fibrils. The charged residues within each repeat prefer exposure to the solvent in order to further stabilize the inter-layered interactions by salt-bridges. The organization of the repeat K(58)T(59)K(60)E(61)Q(62)V(63) between the β2 and β3 layers significantly affects the stability of the non-amyloid-component (NAC) domain. The coupling between the NAC domain and the KTKEGV repeats indicates that both regions can be potential binding sites for inhibitor design. The distinct binding modes of chemical agents that alter αS aggregation highlight the potential of our models in inhibitor design.
Collapse
Affiliation(s)
- Liang Xu
- School of Chemistry, Dalian University of Technology, Dalian, 116024, China
| | - Ruth Nussinov
- Sackler Inst. of Molecular Medicine Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA.
| |
Collapse
|
12
|
Tuttle MD, Comellas G, Nieuwkoop AJ, Covell DJ, Berthold DA, Kloepper KD, Courtney JM, Kim JK, Barclay AM, Kendall A, Wan W, Stubbs G, Schwieters CD, Lee VMY, George JM, Rienstra CM. Solid-state NMR structure of a pathogenic fibril of full-length human α-synuclein. Nat Struct Mol Biol 2016; 23:409-15. [PMID: 27018801 PMCID: PMC5034296 DOI: 10.1038/nsmb.3194] [Citation(s) in RCA: 693] [Impact Index Per Article: 86.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 02/25/2016] [Indexed: 12/17/2022]
Abstract
Misfolded α-synuclein amyloid fibrils are the principal components of Lewy bodies and neurites, hallmarks of Parkinson's disease (PD). We present a high-resolution structure of an α-synuclein fibril, in a form that induces robust pathology in primary neuronal culture, determined by solid-state NMR spectroscopy and validated by EM and X-ray fiber diffraction. Over 200 unique long-range distance restraints define a consensus structure with common amyloid features including parallel, in-register β-sheets and hydrophobic-core residues, and with substantial complexity arising from diverse structural features including an intermolecular salt bridge, a glutamine ladder, close backbone interactions involving small residues, and several steric zippers stabilizing a new orthogonal Greek-key topology. These characteristics contribute to the robust propagation of this fibril form, as supported by the structural similarity of early-onset-PD mutants. The structure provides a framework for understanding the interactions of α-synuclein with other proteins and small molecules, to aid in PD diagnosis and treatment.
Collapse
Affiliation(s)
- Marcus D Tuttle
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Gemma Comellas
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Andrew J Nieuwkoop
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Dustin J Covell
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Institute on Aging, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Deborah A Berthold
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Kathryn D Kloepper
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Joseph M Courtney
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jae K Kim
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Alexander M Barclay
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Amy Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - William Wan
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Gerald Stubbs
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Charles D Schwieters
- Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland, USA
| | - Virginia M Y Lee
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Institute on Aging, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Julia M George
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Chad M Rienstra
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| |
Collapse
|
13
|
Hisao GS, Harland MA, Brown RA, Berthold DA, Wilson TE, Rienstra CM. An efficient method and device for transfer of semisolid materials into solid-state NMR spectroscopy rotors. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 265:172-6. [PMID: 26905816 PMCID: PMC4818695 DOI: 10.1016/j.jmr.2016.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 01/17/2016] [Indexed: 05/23/2023]
Abstract
The study of mass-limited biological samples by magic angle spinning (MAS) solid-state NMR spectroscopy critically relies upon the high-yield transfer of material from a biological preparation into the MAS rotor. This issue is particularly important for maintaining biological activity and hydration of semi-solid samples such as membrane proteins in lipid bilayers, pharmaceutical formulations, microcrystalline proteins and protein fibrils. Here we present protocols and designs for rotor-packing devices specifically suited for packing hydrated samples into Pencil-style 1.6 mm, 3.2 mm standard, and 3.2 mm limited speed MAS rotors. The devices are modular and therefore readily adaptable to other rotor and/or ultracentrifugation tube geometries.
Collapse
Affiliation(s)
- Grant S Hisao
- University of Illinois at Urbana-Champaign, Department of Chemistry, 600 South Mathews Avenue, Urbana, IL 61801, USA.
| | - Michael A Harland
- University of Illinois at Urbana-Champaign, School of Chemical Sciences Machine Shop, 505 South Matthews Ave., Urbana, IL 61801, USA.
| | - Robert A Brown
- University of Illinois at Urbana-Champaign, School of Chemical Sciences Machine Shop, 505 South Matthews Ave., Urbana, IL 61801, USA
| | - Deborah A Berthold
- University of Illinois at Urbana-Champaign, Department of Chemistry, 600 South Mathews Avenue, Urbana, IL 61801, USA.
| | - Thomas E Wilson
- University of Illinois at Urbana-Champaign, School of Chemical Sciences Machine Shop, 505 South Matthews Ave., Urbana, IL 61801, USA.
| | - Chad M Rienstra
- University of Illinois at Urbana-Champaign, Department of Chemistry, 600 South Mathews Avenue, Urbana, IL 61801, USA; University of Illinois at Urbana-Champaign, Department of Biochemistry, Center for Biophysics and Quantitative Biology, 600 South Mathews Avenue, Urbana, IL 61801, USA.
| |
Collapse
|
14
|
Abstract
Solid-state NMR spectroscopy (SSNMR) is an established and invaluable tool for the study of amyloid fibril structure with atomic-level detail. Optimization of the homogeneity and concentration of fibrils enhances the resolution and sensitivity of SSNMR spectra. Here, we present a fibrillization and fibril processing protocol, starting from purified monomeric α-synuclein, that enables the collection of high-resolution SSNMR spectra suitable for site-specific structural analysis. This protocol does not rely on any special features of α-synuclein and should be generalizable to any other amyloid protein.
Collapse
|
15
|
Atsmon-Raz Y, Miller Y. A Proposed Atomic Structure of the Self-Assembly of the Non-Amyloid-β Component of Human α-Synuclein As Derived by Computational Tools. J Phys Chem B 2015; 119:10005-15. [PMID: 26147432 DOI: 10.1021/acs.jpcb.5b03760] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
α-Synuclein (AS) fibrils are the major hallmarks of Parkinson's disease (PD). It is known that the central domain of the 140-residue AS protein, known as the non-amyloid-β component (NAC), plays a crucial role in aggregation. The secondary structure of AS fibrils (including the NAC domain) has been proposed on the basis of solid-state nuclear magnetic resonance studies, but the atomic structure of the self-assembly of NAC (or AS itself) is still elusive. This is the first study that presents a detailed three-dimensional structure of NAC at atomic resolution. The proposed self-assembled structure of NAC consists of three β-strands connected by two turn regions. Our study shows that calculated structural parameter values of the simulated fibril-like cross-β structure of NAC are in excellent agreement with the experimental values. Moreover, the diameter dimensions of the proposed fibril-like structure are also in agreement with experimental measurements. The proposed fibril-like structure of NAC may assist in future work aimed at understanding the formation of aggregates in PD and developing compounds to modulate aggregation.
Collapse
Affiliation(s)
- Yoav Atsmon-Raz
- †Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.,‡Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Yifat Miller
- †Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.,‡Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| |
Collapse
|
16
|
Potapov A, Yau WM, Ghirlando R, Thurber KR, Tycko R. Successive Stages of Amyloid-β Self-Assembly Characterized by Solid-State Nuclear Magnetic Resonance with Dynamic Nuclear Polarization. J Am Chem Soc 2015; 137:8294-307. [PMID: 26068174 PMCID: PMC5559291 DOI: 10.1021/jacs.5b04843] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Self-assembly of amyloid-β (Aβ) peptides in human brain tissue leads to neurodegeneration in Alzheimer's disease (AD). Amyloid fibrils, whose structures have been extensively characterized by solid state nuclear magnetic resonance (ssNMR) and other methods, are the thermodynamic end point of Aβ self-assembly. Oligomeric and protofibrillar assemblies, whose structures are less well-understood, are also observed as intermediates in the assembly process in vitro and have been implicated as important neurotoxic species in AD. We report experiments in which the structural evolution of 40-residue Aβ (Aβ40) is monitored by ssNMR measurements on frozen solutions prepared at four successive stages of the self-assembly process. Measurements on transient intermediates are enabled by ssNMR signal enhancements from dynamic nuclear polarization (DNP) at temperatures below 30 K. DNP-enhanced ssNMR data reveal a monotonic increase in conformational order from an initial state comprised primarily of monomers and small oligomers in solution at high pH, to larger oligomers near neutral pH, to metastable protofibrils, and finally to fibrils. Surprisingly, the predominant molecular conformation, indicated by (13)C NMR chemical shifts and by side chain contacts between F19 and L34 residues, is qualitatively similar at all stages. However, the in-register parallel β-sheet supramolecular structure, indicated by intermolecular (13)C spin polarization transfers, does not develop before the fibril stage. This work represents the first application of DNP-enhanced ssNMR to the characterization of peptide or protein self-assembly intermediates.
Collapse
Affiliation(s)
- Alexey Potapov
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Kent R. Thurber
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| |
Collapse
|
17
|
Colvin MT, Silvers R, Frohm B, Su Y, Linse S, Griffin RG. High resolution structural characterization of Aβ42 amyloid fibrils by magic angle spinning NMR. J Am Chem Soc 2015; 137:7509-18. [PMID: 26001057 PMCID: PMC4623963 DOI: 10.1021/jacs.5b03997] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
![]()
The presence of amyloid plaques composed
of amyloid beta (Aβ)
fibrils is a hallmark of Alzheimer’s disease (AD). The Aβ
peptide is present as several length variants with two common alloforms
consisting of 40 and 42 amino acids, denoted Aβ1–40 and Aβ1–42, respectively. While there have
been numerous reports that structurally characterize fibrils of Aβ1–40, very little is known about the structure of amyloid
fibrils of Aβ1–42, which are considered the
more toxic alloform involved in AD. We have prepared isotopically 13C/15N labeled AβM01–42 fibrils in vitro from recombinant protein and examined their 13C–13C and 13C–15N magic angle spinning (MAS) NMR spectra. In contrast to several
other studies of Aβ fibrils, we observe spectra with excellent
resolution and a single set of chemical shifts, suggesting the presence
of a single fibril morphology. We report the initial structural characterization
of AβM01–42 fibrils utilizing 13C and 15N shift assignments of 38 of the 43 residues,
including the backbone and side chains, obtained through a series
of cross-polarization based 2D and 3D 13C–13C, 13C–15N MAS NMR experiments for rigid
residues along with J-based 2D TOBSY experiments for dynamic residues.
We find that the first ∼5 residues are dynamic and most efficiently
detected in a J-based TOBSY spectrum. In contrast, residues 16–42
are easily observed in cross-polarization experiments and most likely
form the amyloid core. Calculation of ψ and φ dihedral
angles from the chemical shift assignments indicate that 4 β-strands
are present in the fibril’s secondary structure.
Collapse
Affiliation(s)
- Michael T Colvin
- †Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Robert Silvers
- †Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Birgitta Frohm
- ‡Department of Biochemistry and Structural Biology, Lund University, SE22100 Lund, Sweden
| | - Yongchao Su
- †Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Sara Linse
- ‡Department of Biochemistry and Structural Biology, Lund University, SE22100 Lund, Sweden
| | - Robert G Griffin
- †Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
18
|
Gath J, Bousset L, Habenstein B, Melki R, Böckmann A, Meier BH. Unlike twins: an NMR comparison of two α-synuclein polymorphs featuring different toxicity. PLoS One 2014; 9:e90659. [PMID: 24599158 PMCID: PMC3944079 DOI: 10.1371/journal.pone.0090659] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 02/05/2014] [Indexed: 11/18/2022] Open
Abstract
We structurally compare, using solid-state NMR, two different polymorphs of α-synuclein which, as established recently, display contrasting biochemical properties, toxicity, and tropism for cells. We show that both forms, which can each be produced as a pure polymorph, are greatly different in secondary structure. While β-sheets are the dominating secondary structure elements for both polymorphs, they are markedly divergent in terms of number of elements, as well as their distribution. We demonstrate that all identified β-sheets feature an in-register parallel stacking for both polymorphs. The two forms show a different molecular arrangement in the unit cell and distinct dynamic features, while sharing a highly flexible C-terminal domain. The use of reproducible, well-identified conditions for sample preparation and the recording of identical NMR experiments allows for a direct comparison of the results.
Collapse
Affiliation(s)
- Julia Gath
- Physical Chemistry, ETH Zürich, Zurich, Switzerland
| | - Luc Bousset
- Laboratoire d′Enzymologie et Biochimie Structurales, UPR 3082 CNRS, Gif-sur-Yvette, France
| | - Birgit Habenstein
- Institut de Biologie et Chimie des Protéines, UMR 5086 CNRS/Université de Lyon 1, Lyon, France
| | - Ronald Melki
- Laboratoire d′Enzymologie et Biochimie Structurales, UPR 3082 CNRS, Gif-sur-Yvette, France
| | - Anja Böckmann
- Institut de Biologie et Chimie des Protéines, UMR 5086 CNRS/Université de Lyon 1, Lyon, France
| | | |
Collapse
|
19
|
Goobes G. Past and Future Solid-State NMR Spectroscopy Studies at the Convergence Point between Biology and Materials Research. Isr J Chem 2014. [DOI: 10.1002/ijch.201300113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
20
|
Loquet A, Habenstein B, Lange A. Structural investigations of molecular machines by solid-state NMR. Acc Chem Res 2013; 46:2070-9. [PMID: 23496894 DOI: 10.1021/ar300320p] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Essential biological processes such as cell motion, signaling,protein synthesis, and pathogen-host interactions rely on multifunctional molecular machines containing supramolecular assemblies, that is, noncovalently assembled protein subunits. Scientists would like to acquire a detailed atomic view of the complete molecular machine to understand its assembly process and functions. Structural biologists have used various approaches to obtain structural information such as X-ray crystallography, solution NMR, and electron microscopy. The inherent insolubility and large size of these multicomponent assemblies restrict the use of solution NMR, and their noncrystallinity and elongated shapes present obstacles to X-ray crystallography studies. Not limited by molecular weight or crystallinity, solid-state NMR (ssNMR) allows for structural investigations of supramolecular assemblies such as helical filaments, cross-β fibrils, or membrane-embedded oligomeric proteins. In this Account, we describe recent progress in the application of ssNMR to the elucidation of atomic structures of supramolecular assemblies. We highlight ssNMR methods to determine the subunit interfaces in symmetric arrangements. Our use of [1-(13)C]- or [2-(13)C]-glucose as a carbon source during bacterial protein expression results in significant (13)C spin dilution that drastically improves the spectral quality and enables us to detect meaningful structural restraints. Moreover, we can unequivocally determine intermolecular restraints using mixed [(1:1)1-(13)C/2-(13)C]-glucose labeled assemblies. We recently illustrated the power of this methodology with the structure determination of the type III secretion system (T3SS) needle. One crucial aspect in elucidating the atomic structure of these large multicomponent complexes is to determine the subunit-subunit interfaces. Notably, we could probe the needle subunit interfaces by collecting (13)C-(13)C intermolecular restraints. In contrast, these interfaces are not accessible via high-resolution cryo-EM. This approach is readily applicable to other supramolecular assemblies containing symmetrically repeating protein subunits, and could be combined with other techniques to get a more complete picture of multicomponent structures. To determine near-atomic structures of assemblies of biological interest, researchers could combine ssNMR data collected at the subunit interfaces with the envelope obtained from cryo-EM and potentially with monomeric subunit crystal structures.
Collapse
Affiliation(s)
- Antoine Loquet
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Birgit Habenstein
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Adam Lange
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| |
Collapse
|
21
|
Tang M, Comellas G, Rienstra CM. Advanced solid-state NMR approaches for structure determination of membrane proteins and amyloid fibrils. Acc Chem Res 2013; 46:2080-8. [PMID: 23659727 DOI: 10.1021/ar4000168] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Solid-state NMR (SSNMR) spectroscopy has become an important technique for studying the biophysics and structure biology of proteins. This technique is especially useful for insoluble membrane proteins and amyloid fibrils, which are essential for biological functions and are associated with human diseases. In the past few years, as major contributors to the rapidly advancing discipline of biological SSNMR, we have developed a family of methods for high-resolution structure determination of microcrystalline, fibrous, and membrane proteins. Key developments include order-of-magnitude improvements in sensitivity, resolution, instrument stability, and sample longevity under data collection conditions. These technical advances now enable us to apply new types of 3D and 4D experiments to collect atomic-resolution structural restraints in a site-resolved manner, such as vector angles, chemical shift tensors, and internuclear distances, throughout large proteins. In this Account, we present the technological advances in SSNMR approaches towards protein structure determination. We also describe the application of those methods for large membrane proteins and amyloid fibrils. Particularly, the SSNMR measurements of an integral membrane protein DsbB support the formation of a charge-transfer complex between DsbB and ubiquinone during the disulfide bond transfer pathways. The high-resolution structure of the DsbA-DsbB complex demonstrates that the joint calculation of X-ray and SSNMR restraints for membrane proteins with low-resolution crystal structure is generally applicable. The SSNMR investigations of α-synuclein fibrils from both wild type and familial mutants reveal that the structured regions of α-synuclein fibrils include the early-onset Parkinson's disease mutation sites. These results pave the way to understanding the mechanism of fibrillation in Parkinson's disease.
Collapse
Affiliation(s)
- Ming Tang
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Gemma Comellas
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Chad M. Rienstra
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| |
Collapse
|
22
|
Kraus A, Groveman BR, Caughey B. Prions and the potential transmissibility of protein misfolding diseases. Annu Rev Microbiol 2013; 67:543-64. [PMID: 23808331 DOI: 10.1146/annurev-micro-092412-155735] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Prions, or infectious proteins, represent a major frontier in the study of infectious agents. The prions responsible for mammalian transmissible spongiform encephalopathies (TSEs) are due primarily to infectious self-propagation of misfolded prion proteins. TSE prion structures remain ill-defined, other than being highly structured, self-propagating, and often fibrillar protein multimers with the capacity to seed, or template, the conversion of their normal monomeric precursors into a pathogenic form. Purified TSE prions usually take the form of amyloid fibrils, which are self-seeding ultrastructures common to many serious protein misfolding diseases such as Alzheimer's, Parkinson's, Huntington's and Lou Gehrig's (amytrophic lateral sclerosis). Indeed, recent reports have now provided evidence of prion-like propagation of several misfolded proteins from cell to cell, if not from tissue to tissue or individual to individual. These findings raise concerns that various protein misfolding diseases might have spreading, prion-like etiologies that contribute to pathogenesis or prevalence.
Collapse
Affiliation(s)
- Allison Kraus
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840;
| | | | | |
Collapse
|
23
|
Comellas G, Rienstra CM. Protein Structure Determination by Magic-Angle Spinning Solid-State NMR, and Insights into the Formation, Structure, and Stability of Amyloid Fibrils. Annu Rev Biophys 2013; 42:515-36. [DOI: 10.1146/annurev-biophys-083012-130356] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Chad M. Rienstra
- Center for Biophysics and Computational Biology,
- Department of Chemistry, and
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; ,
| |
Collapse
|
24
|
Abstract
Solid-state NMR spectroscopy proved to be a versatile tool for characterization of structure and dynamics of complex biochemical systems. In particular, magic angle spinning (MAS) solid-state NMR came to maturity for application towards structural elucidation of biological macromolecules. Current challenges in applying solid-state NMR as well as progress achieved recently will be discussed in the following chapter focusing on conceptual aspects important for structural elucidation of proteins.
Collapse
Affiliation(s)
- Henrik Müller
- Institute of Physical Biology, Heinrich-Heine-University of Düsseldorf, 40225, Düsseldorf, Germany
| | | | | |
Collapse
|
25
|
Pivato M, De Franceschi G, Tosatto L, Frare E, Kumar D, Aioanei D, Brucale M, Tessari I, Bisaglia M, Samori B, de Laureto PP, Bubacco L. Covalent α-synuclein dimers: chemico-physical and aggregation properties. PLoS One 2012; 7:e50027. [PMID: 23272053 PMCID: PMC3521728 DOI: 10.1371/journal.pone.0050027] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 10/15/2012] [Indexed: 11/29/2022] Open
Abstract
The aggregation of α-synuclein into amyloid fibrils constitutes a key step in the onset of Parkinson's disease. Amyloid fibrils of α-synuclein are the major component of Lewy bodies, histological hallmarks of the disease. Little is known about the mechanism of aggregation of α-synuclein. During this process, α-synuclein forms transient intermediates that are considered to be toxic species. The dimerization of α-synuclein could represent a rate-limiting step in the aggregation of the protein. Here, we analyzed four covalent dimers of α-synuclein, obtained by covalent link of the N-terms, C-terms, tandem cloning of two sequences and tandem juxtaposition in one protein of the 1–104 and 29–140 sequences. Their biophysical properties in solution were determined by CD, FT-IR and NMR spectroscopies. SDS-induced folding was also studied. The fibrils formation was analyzed by ThT and polarization fluorescence assays. Their morphology was investigated by TEM and AFM-based quantitative morphometric analysis. All dimers were found to be devoid of ordered secondary structure under physiological conditions and undergo α-helical transition upon interaction with SDS. All protein species are able to form amyloid-like fibrils. The reciprocal orientation of the α-synuclein monomers in the dimeric constructs affects the kinetics of the aggregation process and a scale of relative amyloidogenic propensity was determined. Structural investigations by FT IR spectroscopy, and proteolytic mapping of the fibril core did not evidence remarkable difference among the species, whereas morphological analyses showed that fibrils formed by dimers display a lower and diversified level of organization in comparison with α-synuclein fibrils. This study demonstrates that although α-synuclein dimerization does not imply the acquisition of a preferred conformation by the participating monomers, it can strongly affect the aggregation properties of the molecules. The results presented highlight a substantial role of the relative orientation of the individual monomer in the definition of the fibril higher structural levels.
Collapse
Affiliation(s)
- Micaela Pivato
- CRIBI Biotechnology Centre, University of Padova, Padova, Italy
| | | | - Laura Tosatto
- University of Padova, Department of Biology, Padova, Italy
| | - Erica Frare
- CRIBI Biotechnology Centre, University of Padova, Padova, Italy
| | - Dhruv Kumar
- University of Bologna, Department of Biochemistry, Bologna, Italy
| | - Daniel Aioanei
- University of Bologna, Department of Biochemistry, Bologna, Italy
| | - Marco Brucale
- CNR, Institute of Nanostructured Materials (ISMN), Montelibretti, Roma, Italy
| | | | - Marco Bisaglia
- University of Padova, Department of Biology, Padova, Italy
| | - Bruno Samori
- University of Bologna, Department of Biochemistry, Bologna, Italy
| | | | - Luigi Bubacco
- University of Padova, Department of Biology, Padova, Italy
- * E-mail: (PPDL); (LB)
| |
Collapse
|
26
|
Daebel V, Chinnathambi S, Biernat J, Schwalbe M, Habenstein B, Loquet A, Akoury E, Tepper K, Müller H, Baldus M, Griesinger C, Zweckstetter M, Mandelkow E, Vijayan V, Lange A. β-Sheet Core of Tau Paired Helical Filaments Revealed by Solid-State NMR. J Am Chem Soc 2012; 134:13982-9. [DOI: 10.1021/ja305470p] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Venita Daebel
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| | - Subashchandrabose Chinnathambi
- DZNE, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee
2, 53175 Bonn, Germany
- CAESAR Research Center, Ludwig-Erhard-Allee 2, 53175
Bonn, Germany
| | - Jacek Biernat
- DZNE, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee
2, 53175 Bonn, Germany
- CAESAR Research Center, Ludwig-Erhard-Allee 2, 53175
Bonn, Germany
| | - Martin Schwalbe
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| | - Birgit Habenstein
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| | - Antoine Loquet
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| | - Elias Akoury
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| | - Katharina Tepper
- DZNE, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee
2, 53175 Bonn, Germany
- CAESAR Research Center, Ludwig-Erhard-Allee 2, 53175
Bonn, Germany
| | - Henrik Müller
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| | - Marc Baldus
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| | - Christian Griesinger
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| | - Markus Zweckstetter
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
- DZNE, German Center for Neurodegenerative Diseases, Grisebachstraße
5, 37077 Göttingen, Germany
| | - Eckhard Mandelkow
- DZNE, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee
2, 53175 Bonn, Germany
- CAESAR Research Center, Ludwig-Erhard-Allee 2, 53175
Bonn, Germany
| | - Vinesh Vijayan
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| | - Adam Lange
- NMR-based
Structural Biology, Max Planck Institute for Biophysical Chemistry, Am
Fassberg 11, 37077 Göttingen, Germany
| |
Collapse
|
27
|
Gath J, Habenstein B, Bousset L, Melki R, Meier BH, Böckmann A. Solid-state NMR sequential assignments of α-synuclein. BIOMOLECULAR NMR ASSIGNMENTS 2012; 6:51-55. [PMID: 21744165 DOI: 10.1007/s12104-011-9324-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 06/27/2011] [Indexed: 05/31/2023]
Abstract
Parkinson's disease is amongst the most frequent and most devastating neurodegenerative diseases. It is tightly associated with the assembly of proteins into high-molecular weight protein species, which propagate between neurons in the central nervous system. The principal protein involved in this process is α-synuclein which is a structural component of the Lewy bodies observed in diseased brain. We here present the solid-state NMR sequential assignments of a new fibrillar form of this protein, the first one with a well-ordered and rigid N-terminal part.
Collapse
Affiliation(s)
- Julia Gath
- Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland
| | | | | | | | | | | |
Collapse
|
28
|
Comellas G, Lemkau LR, Nieuwkoop AJ, Kloepper KD, Ladror DT, Ebisu R, Woods WS, Lipton AS, George JM, Rienstra CM. Structured regions of α-synuclein fibrils include the early-onset Parkinson's disease mutation sites. J Mol Biol 2011; 411:881-95. [PMID: 21718702 PMCID: PMC3157309 DOI: 10.1016/j.jmb.2011.06.026] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 06/07/2011] [Accepted: 06/15/2011] [Indexed: 11/20/2022]
Abstract
α-Synuclein (AS) fibrils are the major component of Lewy bodies, the pathological hallmark of Parkinson's disease (PD). Here, we use results from an extensive investigation employing solid-state NMR to present a detailed structural characterization and conformational dynamics quantification of full-length AS fibrils. Our results show that the core extends with a repeated structural motif. This result disagrees with the previously proposed fold of AS fibrils obtained with limited solid-state NMR data. Additionally, our results demonstrate that the three single point mutations associated with early-onset PD-A30P, E46K and A53T-are located in structured regions. We find that E46K and A53T mutations, located in rigid β-strands of the wild-type fibrils, are associated with major and minor structural perturbations, respectively.
Collapse
Affiliation(s)
- Gemma Comellas
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
| | - Luisel R. Lemkau
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
| | - Andrew J. Nieuwkoop
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
| | - Kathryn D. Kloepper
- Department of Chemistry, Mercer University, 1400 Coleman Avenue, Macon, Georgia, 31207, USA
| | - Daniel T. Ladror
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
| | - Reika Ebisu
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
| | - Wendy S. Woods
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
| | - Andrew S. Lipton
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA
| | - Julia M. George
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
| | - Chad M. Rienstra
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA
| |
Collapse
|
29
|
Cho MK, Kim HY, Fernandez CO, Becker S, Zweckstetter M. Conserved core of amyloid fibrils of wild type and A30P mutant α-synuclein. Protein Sci 2011; 20:387-95. [PMID: 21280130 DOI: 10.1002/pro.570] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The major component of neural inclusions that are the pathological hallmark of Parkinson's disease are amyloid fibrils of the protein α-synuclein (aS). Here we investigated if the disease-related mutation A30P not only modulates the kinetics of aS aggregation, but also alters the structure of amyloid fibrils. To this end we optimized the method of quenched hydrogen/deuterium exchange coupled to NMR spectroscopy and performed two-dimensional proton-detected high-resolution magic angle spinning experiments. The combined data indicate that the A30P mutation does not cause changes in the number, location and overall arrangement of β-strands in amyloid fibrils of aS. At the same time, several residues within the fibrillar core retain nano-second dynamics. We conclude that the increased pathogenicity related to the familial A30P mutation is unlikely to be caused by a mutation-induced change in the conformation of aS aggregates.
Collapse
Affiliation(s)
- Min-Kyu Cho
- Department for NMR based Structural Biology, Max Planck Institute for Biophysical Chemistry, D-37077, Goettingen, Germany
| | | | | | | | | |
Collapse
|
30
|
Linser R, Dasari M, Hiller M, Higman V, Fink U, Lopez del Amo JM, Markovic S, Handel L, Kessler B, Schmieder P, Oesterhelt D, Oschkinat H, Reif B. Festkörper-NMR-Spektroskopie mit Protonendetektion an fibrillären Proteinen und Membranproteinen. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201008244] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
31
|
Linser R, Dasari M, Hiller M, Higman V, Fink U, Lopez del Amo JM, Markovic S, Handel L, Kessler B, Schmieder P, Oesterhelt D, Oschkinat H, Reif B. Proton-detected solid-state NMR spectroscopy of fibrillar and membrane proteins. Angew Chem Int Ed Engl 2011; 50:4508-12. [PMID: 21495136 DOI: 10.1002/anie.201008244] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Indexed: 01/12/2023]
Affiliation(s)
- Rasmus Linser
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin-Buch, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Abstract
Current interest in amyloid fibrils stems from their involvement in neurodegenerative and other diseases and from their role as an alternative structural state for many peptides and proteins. Solid-state nuclear magnetic resonance (NMR) methods have the unique capability of providing detailed structural constraints for amyloid fibrils, sufficient for the development of full molecular models. In this article, recent progress in the application of solid-state NMR to fibrils associated with Alzheimer's disease, prion fibrils, and related systems is reviewed, along with relevant developments in solid-state NMR techniques and technology.
Collapse
Affiliation(s)
- Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
| |
Collapse
|
33
|
Schmidt HLF, Shah GJ, Sperling LJ, Rienstra CM. NMR Determination of Protein pK(a) Values in the Solid State. J Phys Chem Lett 2010; 1:1623-1628. [PMID: 20563223 PMCID: PMC2885713 DOI: 10.1021/jz1004413] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Charged residues play an important role in defining key mechanistic features in many biomolecules. Determining the pK(a) values of large, membrane or fibrillar proteins can be challenging with traditional methods. In this study we show how solid-state NMR is used to monitor chemical shift changes during a pH titration for the small soluble β1 immunoglobulin binding domain of protein G. The chemical shifts of all the amino acids with charged side-chains throughout the uniformly-(13)C,(15)N-labeled protein were monitored over several samples varying in pH; pK(a) values were determined from these shifts for E27, D36, and E42, and the bounds for the pK(a) of other acidic side-chain resonances were determined. Additionally, this study shows how the calculated pK(a) values give insights into the crystal packing of the protein.
Collapse
|
34
|
Nieuwkoop AJ, Wylie BJ, Franks WT, Shah GJ, Rienstra CM. Atomic resolution protein structure determination by three-dimensional transferred echo double resonance solid-state nuclear magnetic resonance spectroscopy. J Chem Phys 2010; 131:095101. [PMID: 19739873 DOI: 10.1063/1.3211103] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We show that quantitative internuclear (15)N-(13)C distances can be obtained in sufficient quantity to determine a complete, high-resolution structure of a moderately sized protein by magic-angle spinning solid-state NMR spectroscopy. The three-dimensional ZF-TEDOR pulse sequence is employed in combination with sparse labeling of (13)C sites in the beta1 domain of the immunoglobulin binding protein G (GB1), as obtained by bacterial expression with 1,3-(13)C or 2-(13)C-glycerol as the (13)C source. Quantitative dipolar trajectories are extracted from two-dimensional (15)N-(13)C planes, in which approximately 750 cross peaks are resolved. The experimental data are fit to exact theoretical trajectories for spin clusters (consisting of one (13)C and several (15)N each), yielding quantitative precision as good as 0.1 A for approximately 350 sites, better than 0.3 A for another 150, and approximately 1.0 A for 150 distances in the range of 5-8 A. Along with isotropic chemical shift-based (TALOS) dihedral angle restraints, the distance restraints are incorporated into simulated annealing calculations to yield a highly precise structure (backbone RMSD of 0.25+/-0.09 A), which also demonstrates excellent agreement with the most closely related crystal structure of GB1 (2QMT, bbRMSD 0.79+/-0.03 A). Moreover, side chain heavy atoms are well restrained (0.76+/-0.06 A total heavy atom RMSD). These results demonstrate for the first time that quantitative internuclear distances can be measured throughout an entire solid protein to yield an atomic-resolution structure.
Collapse
Affiliation(s)
- Andrew J Nieuwkoop
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | | | | | | | | |
Collapse
|
35
|
Synuclein Structure and Function in Parkinson’s Disease. PROTEIN FOLDING AND MISFOLDING: NEURODEGENERATIVE DISEASES 2008. [DOI: 10.1007/978-1-4020-9434-7_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
36
|
Heise H, Celej MS, Becker S, Riedel D, Pelah A, Kumar A, Jovin TM, Baldus M. Solid-state NMR reveals structural differences between fibrils of wild-type and disease-related A53T mutant alpha-synuclein. J Mol Biol 2008; 380:444-50. [PMID: 18539297 DOI: 10.1016/j.jmb.2008.05.026] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 05/07/2008] [Accepted: 05/13/2008] [Indexed: 11/30/2022]
Abstract
Fibrils from the Parkinson's-disease-related A53T mutant of alpha-synuclein were investigated by solid-state NMR spectroscopy, electron microscopy, and atomic force microscopy. Sequential solid-state NMR resonance assignments were obtained for a large fraction of the fibril core. Experiments conducted above and below the freezing point suggest that the fibrils contain regions with increased mobility and structural elements different from beta-strand character, in addition to the rigid beta-sheet-rich core region. As in earlier studies on wild-type alpha-synuclein, the C-terminus was found to be flexible and unfolded, whereas the main core region was highly rigid and rich in beta-sheets. Compared to fibrils from wild-type alpha-synuclein, the well-ordered beta-sheet region extends to at least L38 and L100. These results demonstrate that a disease-related mutant of alpha-synuclein differs in both aggregation kinetics and fibril structure.
Collapse
Affiliation(s)
- Henrike Heise
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Solid-State NMR Group, Am Fassberg 11, D-37077 Göttingen, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Affiliation(s)
- Henrike Heise
- Institute for Physical Biology, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
| |
Collapse
|
38
|
Chapter 6 Molecular and Cellular Biology of Synucleins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 270:225-317. [DOI: 10.1016/s1937-6448(08)01406-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|