1
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Gardon L, Becker N, Rähse N, Hölbling C, Apostolidis A, Schulz CM, Bochinsky K, Gremer L, Heise H, Lakomek NA. Amyloid fibril formation kinetics of low-pH denatured bovine PI3K-SH3 monitored by three different NMR techniques. Front Mol Biosci 2023; 10:1254721. [PMID: 38046811 PMCID: PMC10691488 DOI: 10.3389/fmolb.2023.1254721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 11/06/2023] [Indexed: 12/05/2023] Open
Abstract
Introduction: Misfolding of amyloidogenic proteins is a molecular hallmark of neurodegenerative diseases in humans. A detailed understanding of the underlying molecular mechanisms is mandatory for developing innovative therapeutic approaches. The bovine PI3K-SH3 domain has been a model system for aggregation and fibril formation. Methods: We monitored the fibril formation kinetics of low pH-denatured recombinantly expressed [U-13C, 15N] labeled bovine PI3K-SH3 by a combination of solution NMR, high-resolution magic angle spinning (HR-MAS) NMR and solid-state NMR spectra. Solution NMR offers the highest sensitivity and, therefore, allows for the recording of two-dimensional NMR spectra with residue-specific resolution for individual time points of the time series. However, it can only follow the decay of the aggregating monomeric species. In solution NMR, aggregation occurs under quiescent experimental conditions. Solid-state NMR has lower sensitivity and allows only for the recording of one-dimensional spectra during the time series. Conversely, solid-state NMR is the only technique to detect disappearing monomers and aggregated species in the same sample by alternatingly recoding scalar coupling and dipolar coupling (CP)-based spectra. HR-MAS NMR is used here as a hybrid method bridging solution and solid-state NMR. In solid-state NMR and HR-MAS NMR the sample is agitated due to magic angle spinning. Results: Good agreement of the decay rate constants of monomeric SH3, measured by the three different NMR methods, is observed. Moderate MAS up to 8 kHz seems to influence the aggregation kinetics of seeded fibril formation only slightly. Therefore, under sufficient seeding (1% seeds used here), quiescent conditions (solution NMR), and agitated conditions deliver similar results, arguing against primary nucleation induced by MAS as a major contributor. Using solid-state NMR, we find that the amount of disappeared monomer corresponds approximately to the amount of aggregated species under the applied experimental conditions (250 µM PI3K-SH3, pH 2.5, 298 K, 1% seeds) and within the experimental error range. Data can be fitted by simple mono-exponential conversion kinetics, with lifetimes τ in the 14-38 h range. Atomic force microscopy confirms that fibrils substantially grew in length during the aggregation experiment. This argues for fibril elongation as the dominant growth mechanism in fibril mass (followed by the CP-based solid-state NMR signal). Conclusion: We suggest a combined approach employing both solution NMR and solid-state NMR, back-to-back, on two aliquots of the same sample under seeding conditions as an additional approach to follow monomer depletion and growth of fibril mass simultaneously. Atomic force microscopy images confirm fibril elongation as a major contributor to the increase in fibril mass.
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Affiliation(s)
- Luis Gardon
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Nina Becker
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Nick Rähse
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Christoph Hölbling
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Athina Apostolidis
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Celina M. Schulz
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Kevin Bochinsky
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
| | - Lothar Gremer
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Henrike Heise
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Nils-Alexander Lakomek
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
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2
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Nicastro G, Lucci M, Oregioni A, Kelly G, Frenkiel TA, Taylor IA. CP-MAS and solution NMR studies of allosteric communication in CA-assemblies of HIV-1. J Mol Biol 2022; 434:167691. [PMID: 35738429 DOI: 10.1016/j.jmb.2022.167691] [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: 05/13/2022] [Revised: 06/14/2022] [Accepted: 06/15/2022] [Indexed: 10/18/2022]
Abstract
Solution and solid-state NMR spectroscopy are highly complementary techniques for studying structure and dynamics in very high molecular weight systems. Here we have analysed the dynamics of HIV-1 capsid (CA) assemblies in presence of the cofactors IP6 and ATPγS and the host-factor CPSF6 using a combination of solution state and cross polarisation magic angle spinning (CP-MAS) solid-state NMR. In particular, dynamical effects on ns to µs and µs to ms timescales are observed revealing diverse motions in assembled CA. Using CP-MAS NMR, we exploited the sensitivity of the amide/Cα-Cβ backbone chemical shifts in DARR and NCA spectra to observe the plasticity of the HIV-1 CA tubular assemblies and also map the binding of cofactors and the dynamics of cofactor-CA complexes. In solution, we measured how the addition of host- and co-factors to CA -hexamers perturbed the chemical shifts and relaxation properties of CA-Ile and -Met methyl groups using transverse-relaxation-optimized NMR spectroscopy to exploit the sensitivity of methyl groups as probes in high-molecular weight proteins. These data show how dynamics of the CA protein assembly over a range of spatial and temporal scales play a critical role in CA function. Moreover, we show that binding of IP6, ATPγS and CPSF6 results in local chemical shift as well as dynamic changes for a significant, contiguous portion of CA, highlighting how allosteric pathways communicate ligand interactions between adjacent CA protomers.
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Affiliation(s)
- Giuseppe Nicastro
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Massimo Lucci
- CIRMMP, University of Florence, Via L. Sacconi, 6 50019 Sesto Fiorentino (FI), Italy
| | - Alain Oregioni
- The Medical Research Council Biomedical NMR Centre, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Geoff Kelly
- The Medical Research Council Biomedical NMR Centre, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Tom A Frenkiel
- The Medical Research Council Biomedical NMR Centre, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Ian A Taylor
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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3
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Tong Q, Tan H, Li J, Xie H, Zhao Y, Chen Y, Yang J. Extensively sparse 13C labeling to simplify solid-state NMR 13C spectra of membrane proteins. JOURNAL OF BIOMOLECULAR NMR 2021; 75:245-254. [PMID: 34148188 DOI: 10.1007/s10858-021-00372-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 06/08/2021] [Indexed: 06/12/2023]
Abstract
Solid-state Nuclear Magnetic Resonance (ssNMR) is an emerging technique to investigate the structures and dynamics of membrane proteins in an artificial or native membrane environment. However, the structural studies of proteins by ssNMR are usually prolonged or impeded by signal assignments, especially the assignments of signals for collection of distance restraints, because of serious overlapping of signals in 2D 13C-13C spectra. Sparse labeling of 13C spins is an effective approach to simplify the 13C spectra and facilitate the extractions of distance restraints. Here, we propose a new reverse labeling combination of six types of amino acid residues (Ile, Leu, Phe, Trp, Tyr and Lys), and show a clean reverse labeling effect on a model membrane protein E. coli aquaporin Z (AqpZ). We further combine this reverse labeling combination and alternate 13C-12C labeling, and demonstrate an enhanced dilution effect in 13C-13C spectra. In addition, the influences of reverse labeling on the labeling of the other types of residues are quantitatively analyzed in the two strategies (1, reverse labeling and 2, reverse labeling combining alternate 13C-12C labeling). The signal intensities of some other types of residues in 2D 13C-13C spectra are observed to be 20-50% weaker because of the unwanted reverse labeling. The extensively sparse 13C labeling proposed in this study is expected to be useful in the collection of distance restraints using 2D 13C-13C spectra of membrane proteins.
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Affiliation(s)
- Qiong Tong
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China
| | - Huan Tan
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Jianping Li
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
| | - Huayong Xie
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
| | - Yongxiang Zhao
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
| | - Yanke Chen
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
| | - Jun Yang
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China.
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China.
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4
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Thermodynamics of amyloid fibril formation from non-equilibrium experiments of growth and dissociation. Biophys Chem 2021; 271:106549. [PMID: 33578107 DOI: 10.1016/j.bpc.2021.106549] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/11/2021] [Accepted: 01/11/2021] [Indexed: 12/22/2022]
Abstract
Amyloid fibrils are ordered, non-covalent polymers of proteins that are linked to a range of diseases, as well as biological functions. Amyloid fibrils are often considered thermodynamically so stable that they appear to be irreversible, explaining why very few quantitative thermodynamic studies have been performed on amyloid fibrils, compared to the very large body of kinetic studies. Here we explore the thermodynamics of amyloid fibril formation by the protein PI3K-SH3, which forms amyloid fibrils under acidic conditions. We use quartz crystal microbalance (QCM) and develop novel temperature perturbation experiments based on differential scanning fluorimetry (DSF) to measure the temperature dependence of the fibril growth and dissociation rates, allowing us to quantitatively describe the thermodynamic stability of PI3K-SH3 amyloid fibrils between 10 and 75°C.
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5
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Zou Y, Yu L, Fang X, Zheng Y, Yang Y, Wang C. Position-coded multivalent peptide-peptide interactions revealed by tryptophan-scanning mutagenesis. J Pept Sci 2020; 26:e3273. [PMID: 32583616 DOI: 10.1002/psc.3273] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/06/2020] [Accepted: 06/09/2020] [Indexed: 11/08/2022]
Abstract
We demonstrate in this contribution the evidence that significant cooperative binding effect can be identified for the amino acid sites that are determinant to the binding characteristics in peptide-peptide interactions. The analysis of tryptophan-scanning mutagenesis of the 14-mer peptide consisting only of glycine provides a mapping of position-dependent contributions to the binding energy. The pronounced tryptophan-associated peptide-peptide interactions are originated from the indole moieties with the main chains of 14-mer glycines containing N-H and CO moieties. Specifically, with the presence of two tryptophans as determinant amino acids, cooperative binding can be observed, which are dependent on relative positions of the two tryptophans with a "volcano"-like characteristics. An optimal separation of 6-10 amino acids between two adjacent binding sites can be identified to achieve maximal binding interactions.
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Affiliation(s)
- Yimin Zou
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety, CAS Key Laboratory of Standardization and Measurement for Nanotechnology of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, CAS Center for Excellence in Brain Science, National Center for Nanoscience and Technology, Beijing, China.,Sino-Danish Center for Education and Research, University of Chinese Academy of Sciences, Beijing, China
| | - Lanlan Yu
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety, CAS Key Laboratory of Standardization and Measurement for Nanotechnology of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, CAS Center for Excellence in Brain Science, National Center for Nanoscience and Technology, Beijing, China.,State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Xiaocui Fang
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety, CAS Key Laboratory of Standardization and Measurement for Nanotechnology of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, CAS Center for Excellence in Brain Science, National Center for Nanoscience and Technology, Beijing, China
| | - Yongfang Zheng
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety, CAS Key Laboratory of Standardization and Measurement for Nanotechnology of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, CAS Center for Excellence in Brain Science, National Center for Nanoscience and Technology, Beijing, China.,Department of Chemistry, Tsinghua University, Beijing, China
| | - Yanlian Yang
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety, CAS Key Laboratory of Standardization and Measurement for Nanotechnology of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, CAS Center for Excellence in Brain Science, National Center for Nanoscience and Technology, Beijing, China
| | - Chen Wang
- CAS Key Laboratory of Biological Effects of Nanomaterials and Nanosafety, CAS Key Laboratory of Standardization and Measurement for Nanotechnology of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, CAS Center for Excellence in Brain Science, National Center for Nanoscience and Technology, Beijing, China
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6
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Röder C, Vettore N, Mangels LN, Gremer L, Ravelli RBG, Willbold D, Hoyer W, Buell AK, Schröder GF. Atomic structure of PI3-kinase SH3 amyloid fibrils by cryo-electron microscopy. Nat Commun 2019; 10:3754. [PMID: 31434882 PMCID: PMC6704188 DOI: 10.1038/s41467-019-11320-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/09/2019] [Indexed: 12/18/2022] Open
Abstract
High resolution structural information on amyloid fibrils is crucial for the understanding of their formation mechanisms and for the rational design of amyloid inhibitors in the context of protein misfolding diseases. The Src-homology 3 domain of phosphatidyl-inositol-3-kinase (PI3K-SH3) is a model amyloid system that plays a pivotal role in our basic understanding of protein misfolding and aggregation. Here, we present the atomic model of the PI3K-SH3 amyloid fibril with a resolution determined to 3.4 Å by cryo-electron microscopy (cryo-EM). The fibril is composed of two intertwined protofilaments that create an interface spanning 13 residues from each monomer. The model comprises residues 1-77 out of 86 amino acids in total, with the missing residues located in the highly flexible C-terminus. The fibril structure allows us to rationalise the effects of chemically conservative point mutations as well as of the previously reported sequence perturbations on PI3K-SH3 fibril formation and growth.
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Affiliation(s)
- Christine Röder
- Institute of Complex Systems, Structural Biochemistry (ICS-6) and JuStruct, Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Nicola Vettore
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Lena N Mangels
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Lothar Gremer
- Institute of Complex Systems, Structural Biochemistry (ICS-6) and JuStruct, Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Raimond B G Ravelli
- The Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, The Netherlands
| | - Dieter Willbold
- Institute of Complex Systems, Structural Biochemistry (ICS-6) and JuStruct, Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Wolfgang Hoyer
- Institute of Complex Systems, Structural Biochemistry (ICS-6) and JuStruct, Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Alexander K Buell
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany.
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs, Lyngby, Denmark.
| | - Gunnar F Schröder
- Institute of Complex Systems, Structural Biochemistry (ICS-6) and JuStruct, Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425, Jülich, Germany.
- Physics Department, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany.
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7
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Pell AJ, Pintacuda G, Grey CP. Paramagnetic NMR in solution and the solid state. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 111:1-271. [PMID: 31146806 DOI: 10.1016/j.pnmrs.2018.05.001] [Citation(s) in RCA: 215] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 05/11/2018] [Accepted: 05/12/2018] [Indexed: 05/22/2023]
Abstract
The field of paramagnetic NMR has expanded considerably in recent years. This review addresses both the theoretical description of paramagnetic NMR, and the way in which it is currently practised. We provide a review of the theory of the NMR parameters of systems in both solution and the solid state. Here we unify the different languages used by the NMR, EPR, quantum chemistry/DFT, and magnetism communities to provide a comprehensive and coherent theoretical description. We cover the theory of the paramagnetic shift and shift anisotropy in solution both in the traditional formalism in terms of the magnetic susceptibility tensor, and using a more modern formalism employing the relevant EPR parameters, such as are used in first-principles calculations. In addition we examine the theory first in the simple non-relativistic picture, and then in the presence of spin-orbit coupling. These ideas are then extended to a description of the paramagnetic shift in periodic solids, where it is necessary to include the bulk magnetic properties, such as magnetic ordering at low temperatures. The description of the paramagnetic shift is completed by describing the current understanding of such shifts due to lanthanide and actinide ions. We then examine the paramagnetic relaxation enhancement, using a simple model employing a phenomenological picture of the electronic relaxation, and again using a more complex state-of-the-art theory which incorporates electronic relaxation explicitly. An additional important consideration in the solid state is the impact of bulk magnetic susceptibility effects on the form of the spectrum, where we include some ideas from the field of classical electrodynamics. We then continue by describing in detail the solution and solid-state NMR methods that have been deployed in the study of paramagnetic systems in chemistry, biology, and the materials sciences. Finally we describe a number of case studies in paramagnetic NMR that have been specifically chosen to highlight how the theory in part one, and the methods in part two, can be used in practice. The systems chosen include small organometallic complexes in solution, solid battery electrode materials, metalloproteins in both solution and the solid state, systems containing lanthanide ions, and multi-component materials used in pharmaceutical controlled-release formulations that have been doped with paramagnetic species to measure the component domain sizes.
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Affiliation(s)
- Andrew J Pell
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Svante Arrhenius väg 16 C, SE-106 91 Stockholm, Sweden.
| | - Guido Pintacuda
- Institut des Sciences Analytiques (CNRS UMR 5280, ENS de Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Clare P Grey
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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8
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Roberts EK, Wong KM, Lee EJ, Le MM, Patel DM, Paravastu AK. Post-assembly α-helix to β-sheet structural transformation within SAF-p1/p2a peptide nanofibers. SOFT MATTER 2018; 14:8986-8996. [PMID: 30375627 DOI: 10.1039/c8sm01754a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report an unanticipated helix-to-sheet structural transformation within an assembly of SAF-p1 and SAF-p2a designer peptides. Solid-state NMR spectroscopic data support the assembled structure that was targeted by rational peptide design: an α-helical coiled-coil co-assembly of both peptides. Subsequent to assembly, however, the system converts to a β-sheet structure that continues to exhibit nearest-neighbor interactions between the two peptide components. The structural transition occurs at pH 7.4 and exhibits strongly temperature-dependent kinetics between room temperature (weeks) and 40 °C (minutes). We further observed evidence of reversibility on the timescale of months at 4 °C. The structural conversion from the anticipated structure to an unexpected structure highlights an important aspect to the challenge of designing peptide assemblies. Furthermore, the conformational switching mechanism mediated by a prerequisite α-helical nanostructure represents a previously unknown route for β-sheet designer peptide assembly.
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Affiliation(s)
- Evan K Roberts
- Department of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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9
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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.
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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
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10
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Jain MG, Rajalakshmi G, Equbal A, Mote KR, Agarwal V, Madhu PK. Sine-squared shifted pulses for recoupling interactions in solid-state NMR. J Chem Phys 2017; 146:244201. [PMID: 28668030 DOI: 10.1063/1.4986791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Rotational-Echo DOuble-Resonance (REDOR) is a versatile experiment for measuring internuclear distance between two heteronuclear spins in solid-state NMR. At slow to intermediate magic-angle spinning (MAS) frequencies, the measurement of distances between strongly coupled spins is challenging due to rapid dephasing of magnetisation. This problem can be remedied by employing the pulse-shifted version of REDOR known as Shifted-REDOR (S-REDOR) that scales down the recoupled dipolar coupling. In this study, we propose a new variant of the REDOR sequence where the positions of the π pulses are determined by a sine-squared function. This new variant has scaling properties similar to S-REDOR. We use theory, numerical simulations, and experiments to compare the dipolar recoupling efficiencies and the experimental robustness of the three REDOR schemes. The proposed variant has advantages in terms of radiofrequency field requirements at fast MAS frequencies.
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Affiliation(s)
- Mukul G Jain
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
| | - G Rajalakshmi
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
| | - Asif Equbal
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
| | - Kaustubh R Mote
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
| | - Vipin Agarwal
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
| | - P K Madhu
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
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11
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Piehl D, Blancas-Mejía LM, Wall JS, Kennel SJ, Ramirez-Alvarado M, Rienstra CM. Immunoglobulin Light Chains Form an Extensive and Highly Ordered Fibril Involving the N- and C-Termini. ACS OMEGA 2017; 2:712-720. [PMID: 28261692 PMCID: PMC5331457 DOI: 10.1021/acsomega.6b00494] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Accepted: 02/08/2017] [Indexed: 05/03/2023]
Abstract
Light-chain (AL)-associated amyloidosis is a systemic disorder involving the formation and deposition of immunoglobulin AL fibrils in various bodily organs. One severe instance of AL disease is exhibited by the patient-derived variable domain (VL) of the light chain AL-09, a 108 amino acid residue protein containing seven mutations relative to the corresponding germline protein, κI O18/O8 VL. Previous work has demonstrated that the thermodynamic stability of native AL-09 VL is greatly lowered by two of these mutations, Y87H and N34I, whereas a third mutation, K42Q, further increases the kinetics of fibril formation. However, detailed knowledge regarding the residues that are responsible for stabilizing the misfolded fibril structure is lacking. In this study, using solid-state NMR spectroscopy, we show that the majority of the AL-09 VL sequence is immobilized in the fibrils and that the N- and C-terminal portions of the sequence are particularly well-structured. Thus, AL-09 VL forms an extensively ordered and β-strand-rich fibril structure. Furthermore, we demonstrate that the predominant β-sheet secondary structure and rigidity observed for in vitro prepared AL-09 VL fibrils are qualitatively similar to those observed for AL fibrils extracted from postmortem human spleen tissue, suggesting that this conformation may be representative of a common feature of AL fibrils.
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Affiliation(s)
- Dennis
W. Piehl
- Department
of Biochemistry, Department of Chemistry, and Center for Biophysics and Computational
Biology, University of Illinois at Urbana-Champaign, 600 S Mathews Avenue, Urbana, Illinois 61801, United States
| | - Luis M. Blancas-Mejía
- Department
of Biochemistry and Molecular Biology, Mayo
Clinic, 200 First Street SW, Rochester, Minnesota 55905, United States
| | - Jonathan S. Wall
- Department of Medicine and Department of Radiology, University
of Tennessee Graduate School of Medicine, 1924 Alcoa Hwy, Knoxville, Tennessee 37920, United States
| | - Stephen J. Kennel
- Department of Medicine and Department of Radiology, University
of Tennessee Graduate School of Medicine, 1924 Alcoa Hwy, Knoxville, Tennessee 37920, United States
| | - Marina Ramirez-Alvarado
- Department
of Biochemistry and Molecular Biology, Mayo
Clinic, 200 First Street SW, Rochester, Minnesota 55905, United States
- E-mail: . Phone: (507)-284-2705 (M.R.-A.)
| | - Chad M. Rienstra
- Department
of Biochemistry, Department of Chemistry, and Center for Biophysics and Computational
Biology, University of Illinois at Urbana-Champaign, 600 S Mathews Avenue, Urbana, Illinois 61801, United States
- E-mail: . Phone: (217)-244-4655 (C.M.R.)
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12
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Elkins MR, Wang T, Nick M, Jo H, Lemmin T, Prusiner SB, DeGrado WF, Stöhr J, Hong M. Structural Polymorphism of Alzheimer's β-Amyloid Fibrils as Controlled by an E22 Switch: A Solid-State NMR Study. J Am Chem Soc 2016; 138:9840-52. [PMID: 27414264 PMCID: PMC5149419 DOI: 10.1021/jacs.6b03715] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The amyloid-β (Aβ) peptide of Alzheimer's disease (AD) forms polymorphic fibrils on the micrometer and molecular scales. Various fibril growth conditions have been identified to cause polymorphism, but the intrinsic amino acid sequence basis for this polymorphism has been unclear. Several single-site mutations in the center of the Aβ sequence cause different disease phenotypes and fibrillization properties. The E22G (Arctic) mutant is found in familial AD and forms protofibrils more rapidly than wild-type Aβ. Here, we use solid-state NMR spectroscopy to investigate the structure, dynamics, hydration and morphology of Arctic E22G Aβ40 fibrils. (13)C, (15)N-labeled synthetic E22G Aβ40 peptides are studied and compared with wild-type and Osaka E22Δ Aβ40 fibrils. Under the same fibrillization conditions, Arctic Aβ40 exhibits a high degree of polymorphism, showing at least four sets of NMR chemical shifts for various residues, while the Osaka and wild-type Aβ40 fibrils show a single or a predominant set of chemical shifts. Thus, structural polymorphism is intrinsic to the Arctic E22G Aβ40 sequence. Chemical shifts and inter-residue contacts obtained from 2D correlation spectra indicate that one of the major Arctic conformers has surprisingly high structural similarity with wild-type Aβ42. (13)C-(1)H dipolar order parameters, (1)H rotating-frame spin-lattice relaxation times and water-to-protein spin diffusion experiments reveal substantial differences in the dynamics and hydration of Arctic, Osaka and wild-type Aβ40 fibrils. Together, these results strongly suggest that electrostatic interactions in the center of the Aβ peptide sequence play a crucial role in the three-dimensional fold of the fibrils, and by inference, fibril-induced neuronal toxicity and AD pathogenesis.
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Affiliation(s)
- Matthew R. Elkins
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge MA 02139
| | - Tuo Wang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge MA 02139
| | - Mimi Nick
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158
| | - Thomas Lemmin
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158
| | - Stanley B. Prusiner
- Institute for Neurodegenerative Diseases, Departments of Neurology, University of California, San Francisco, San Francisco, CA 94143
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158
| | - Jan Stöhr
- Institute for Neurodegenerative Diseases, Departments of Neurology, University of California, San Francisco, San Francisco, CA 94143
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge MA 02139
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13
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Crystallographic studies on protein misfolding: Domain swapping and amyloid formation in the SH3 domain. Arch Biochem Biophys 2016; 602:116-126. [PMID: 26924596 DOI: 10.1016/j.abb.2016.02.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 02/19/2016] [Accepted: 02/23/2016] [Indexed: 12/18/2022]
Abstract
Oligomerization by 3D domain swapping is found in a variety of proteins of diverse size, fold and function. In the early 1960s this phenomenon was postulated for the oligomers of ribonuclease A, but it was not until the 1990s that X-ray diffraction provided the first experimental evidence of this special manner of oligomerization. Nowadays, structural information has allowed the identification of these swapped oligomers in over one hundred proteins. Although the functional relevance of this phenomenon is not clear, this alternative folding of protomers into intertwined oligomers has been related to amyloid formation. Studies on proteins that develop 3D domain swapping might provide some clues on the early stages of amyloid formation. The SH3 domain is a small modular domain that has been used as a model to study the basis of protein folding. Among SH3 domains, the c-Src-SH3 domain emerges as a helpful model to study 3D domain swapping and amyloid formation.
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14
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Wenk P, Kaushik M, Richter D, Vogel M, Suess B, Corzilius B. Dynamic nuclear polarization of nucleic acid with endogenously bound manganese. JOURNAL OF BIOMOLECULAR NMR 2015. [PMID: 26219517 DOI: 10.1007/s10858-015-9972-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We report the direct dynamic nuclear polarization (DNP) of (13)C nuclei of a uniformly [(13)C,(15)N]-labeled, paramagnetic full-length hammerhead ribozyme (HHRz) complex with Mn(2+) where the enhanced polarization is fully provided by the endogenously bound metal ion and no exogenous polarizing agent is added. A (13)C enhancement factor of ε = 8 was observed by intra-complex DNP at 9.4 T. In contrast, "conventional" indirect and direct DNP experiments were performed using AMUPol as polarizing agent where we obtained a (1)H enhancement factor of ε ≈ 250. Comparison with the diamagnetic (Mg(2+)) HHRz complex shows that the presence of Mn(2+) only marginally influences the (DNP-enhanced) NMR properties of the RNA. Furthermore two-dimensional correlation spectra ((15)N-(13)C and (13)C-(13)C) reveal structural inhomogeneity in the frozen, amorphous state indicating the coexistence of several conformational states. These demonstrations of intra-complex DNP using an endogenous metal ion as well as DNP-enhanced MAS NMR of RNA in general yield important information for the development of new methods in structural biology.
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Affiliation(s)
- Patricia Wenk
- Institute of Physical und Theoretical Chemistry, Institute of Biophysical Chemistry und Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Max-von-Laue-Str. 7-9, 60438, Frankfurt am Main, Germany
- Werner Siemens Imaging Center and Department of Preclinical Imaging and Radiopharmacy, University of Tübingen, Röntgenweg 13, 72076, Tübingen, Germany
| | - Monu Kaushik
- Institute of Physical und Theoretical Chemistry, Institute of Biophysical Chemistry und Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Max-von-Laue-Str. 7-9, 60438, Frankfurt am Main, Germany
| | - Diane Richter
- Institute of Physical und Theoretical Chemistry, Institute of Biophysical Chemistry und Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Max-von-Laue-Str. 7-9, 60438, Frankfurt am Main, Germany
| | - Marc Vogel
- Department of Biology, Technical University Darmstadt, Schnittspahnstraße 10, 64287, Darmstadt, Germany
| | - Beatrix Suess
- Department of Biology, Technical University Darmstadt, Schnittspahnstraße 10, 64287, Darmstadt, Germany
| | - Björn Corzilius
- Institute of Physical und Theoretical Chemistry, Institute of Biophysical Chemistry und Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Max-von-Laue-Str. 7-9, 60438, Frankfurt am Main, Germany.
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15
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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.
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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
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16
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Su Y, Andreas L, Griffin RG. Magic angle spinning NMR of proteins: high-frequency dynamic nuclear polarization and (1)H detection. Annu Rev Biochem 2015; 84:465-97. [PMID: 25839340 DOI: 10.1146/annurev-biochem-060614-034206] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magic angle spinning (MAS) NMR studies of amyloid and membrane proteins and large macromolecular complexes are an important new approach to structural biology. However, the applicability of these experiments, which are based on (13)C- and (15)N-detected spectra, would be enhanced if the sensitivity were improved. Here we discuss two advances that address this problem: high-frequency dynamic nuclear polarization (DNP) and (1)H-detected MAS techniques. DNP is a sensitivity enhancement technique that transfers the high polarization of exogenous unpaired electrons to nuclear spins via microwave irradiation of electron-nuclear transitions. DNP boosts NMR signal intensities by factors of 10(2) to 10(3), thereby overcoming NMR's inherent low sensitivity. Alternatively, it permits structural investigations at the nanomolar scale. In addition, (1)H detection is feasible primarily because of the development of MAS rotors that spin at frequencies of 40 to 60 kHz or higher and the preparation of extensively (2)H-labeled proteins.
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Affiliation(s)
- Yongchao Su
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139;
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17
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Electrostatic effects in the folding of the SH3 domain of the c-Src tyrosine kinase: pH-dependence in 3D-domain swapping and amyloid formation. PLoS One 2014; 9:e113224. [PMID: 25490095 PMCID: PMC4260792 DOI: 10.1371/journal.pone.0113224] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 10/20/2014] [Indexed: 11/19/2022] Open
Abstract
The SH3 domain of the c-Src tyrosine kinase (c-Src-SH3) aggregates to form intertwined dimers and amyloid fibrils at mild acid pHs. In this work, we show that a single mutation of residue Gln128 of this SH3 domain has a significant effect on: (i) its thermal stability; and (ii) its propensity to form amyloid fibrils. The Gln128Glu mutant forms amyloid fibrils at neutral pH but not at mild acid pH, while Gln128Lys and Gln128Arg mutants do not form these aggregates under any of the conditions assayed. We have also solved the crystallographic structures of the wild-type (WT) and Gln128Glu, Gln128Lys and Gln128Arg mutants from crystals obtained at different pHs. At pH 5.0, crystals belong to the hexagonal space group P6522 and the asymmetric unit is formed by one chain of the protomer of the c-Src-SH3 domain in an open conformation. At pH 7.0, crystals belong to the orthorhombic space group P212121, with two molecules at the asymmetric unit showing the characteristic fold of the SH3 domain. Analysis of these crystallographic structures shows that the residue at position 128 is connected to Glu106 at the diverging β-turn through a cluster of water molecules. Changes in this hydrogen-bond network lead to the displacement of the c-Src-SH3 distal loop, resulting also in conformational changes of Leu100 that might be related to the binding of proline rich motifs. Our findings show that electrostatic interactions and solvation of residues close to the folding nucleation site of the c-Src-SH3 domain might play an important role during the folding reaction and the amyloid fibril formation.
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18
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Hsu STD. NMR assignments of PI3-SH3 domain aided by protonless NMR spectroscopy. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:291-295. [PMID: 23832674 DOI: 10.1007/s12104-013-9503-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Accepted: 06/29/2013] [Indexed: 06/02/2023]
Abstract
We report here the near complete assignments of native bovine PI3-SH3 domain, which has been a model system for protein folding, misfolding and amyloid fibril formation. The use of (13)C-detected protonless NMR spectroscopy is instrumental in assigning the spin system of the proline residue at the C-terminus in addition to the missing resonances in proton-based NMR spectra due to rapid solvent exchange. It also helps assign the resonances of all three proline amine nitrogen nuclei, which are underrepresented in the database. Comparison of the backbone (13)C resonances of PI3-SH3 in its native and amyloid fibril states shows that the aggregation of PI3-SH3 is accompanied by major conformational rearrangements.
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Affiliation(s)
- Shang-Te Danny Hsu
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK,
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19
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Tycko R. Physical and structural basis for polymorphism in amyloid fibrils. Protein Sci 2014; 23:1528-39. [PMID: 25179159 DOI: 10.1002/pro.2544] [Citation(s) in RCA: 176] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 12/24/2022]
Abstract
As our understanding of the molecular structures of amyloid fibrils has matured over the past 15 years, it has become clear that, while amyloid fibrils do have well-defined molecular structures, their molecular structures are not uniquely determined by the amino acid sequences of their constituent peptides and proteins. Self-propagating molecular-level polymorphism is a common phenomenon. This article reviews current information about amyloid fibril structures, variations in molecular structures that underlie amyloid polymorphism, and physical considerations that explain the development and persistence of amyloid polymorphism. Much of this information has been obtained through solid state nuclear magnetic resonance measurements. The biological significance of amyloid polymorphism is also discussed briefly. Although this article focuses primarily on studies of fibrils formed by amyloid-β peptides, the same principles apply to many amyloid-forming peptides and proteins.
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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
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20
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Su Y, Sarell CJ, Eddy MT, Debelouchina GT, Andreas LB, Pashley CL, Radford SE, Griffin RG. Secondary structure in the core of amyloid fibrils formed from human β₂m and its truncated variant ΔN6. J Am Chem Soc 2014; 136:6313-25. [PMID: 24679070 PMCID: PMC4017606 DOI: 10.1021/ja4126092] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
![]()
Amyloid
fibrils formed from initially soluble proteins with diverse
sequences are associated with an array of human diseases. In the human
disorder, dialysis-related amyloidosis (DRA), fibrils contain two
major constituents, full-length human β2-microglobulin
(hβ2m) and a truncation variant, ΔN6 which
lacks the N-terminal six amino acids. These fibrils are assembled
from initially natively folded proteins with an all antiparallel β-stranded
structure. Here, backbone conformations of wild-type hβ2m and ΔN6 in their amyloid forms have been determined
using a combination of dilute isotopic labeling strategies and multidimensional
magic angle spinning (MAS) NMR techniques at high magnetic fields,
providing valuable structural information at the atomic-level about
the fibril architecture. The secondary structures of both fibril types,
determined by the assignment of ∼80% of the backbone resonances
of these 100- and 94-residue proteins, respectively, reveal substantial
backbone rearrangement compared with the location of β-strands
in their native immunoglobulin folds. The identification of seven
β-strands in hβ2m fibrils indicates that approximately
70 residues are in a β-strand conformation in the fibril core.
By contrast, nine β-strands comprise the fibrils formed from
ΔN6, indicating a more extensive core. The precise location
and length of β-strands in the two fibril forms also differ.
The results indicate fibrils of ΔN6 and hβ2m have an extensive core architecture involving the majority of residues
in the polypeptide sequence. The common elements of the backbone structure
of the two proteins likely facilitates their ability to copolymerize
during amyloid fibril assembly.
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Affiliation(s)
- Yongchao Su
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology Cambridge, Massachusetts 02139, United States
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21
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Solid-state NMR studies of metal-free SOD1 fibrillar structures. J Biol Inorg Chem 2014; 19:659-66. [PMID: 24719206 DOI: 10.1007/s00775-014-1130-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 03/10/2014] [Indexed: 10/25/2022]
Abstract
Copper-zinc superoxide dismutase 1 (SOD1) is present in the protein aggregates deposited in motor neurons of amyotrophic lateral sclerosis (ALS) patients. ALS is a neurodegenerative disease that can be either sporadic (ca. 90%) or familial (fALS). The most widely studied forms of fALS are caused by mutations in the sequence of SOD1. Ex mortuo SOD1 aggregates are usually found to be amorphous. In vitro SOD1, in its immature reduced and apo state, forms fibrillar aggregates. Previous literature data have suggested that a monomeric SOD1 construct, lacking loops IV and VII, (apoSODΔIV-VII), shares the same fibrillization properties of apoSOD1, both proteins having the common structural feature of the central β-barrel. In this work, we show that structural information can be obtained at a site-specific level from solid-state NMR. The residues that are sequentially assignable are found to be located at the putative nucleation site for fibrillar species formation in apoSOD, as detected by other experimental techniques.
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22
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Michaelis VK, Ong TC, Kiesewetter MK, Frantz DK, Walish JJ, Ravera E, Luchinat C, Swager TM, Griffin RG. Topical Developments in High-Field Dynamic Nuclear Polarization. Isr J Chem 2014; 54:207-221. [PMID: 25977588 DOI: 10.1002/ijch.201300126] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We report our recent efforts directed at improving high-field DNP experiments. We investigated a series of thiourea nitroxide radicals and the associated DNP enhancements ranging from ε = 25 to 82 that demonstrate the impact of molecular structure on performance. We directly polarized low-gamma nuclei including 13C, 2H, and 17O using trityl via the cross effect. We discuss a variety of sample preparation techniques for DNP with emphasis on the benefit of methods that do not use a glass-forming cryoprotecting matrix. Lastly, we describe a corrugated waveguide for use in a 700 MHz / 460 GHz DNP system that improves microwave delivery and increases enhancements up to 50%.
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Affiliation(s)
- Vladimir K Michaelis
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Ta-Chung Ong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Matthew K Kiesewetter
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Derik K Frantz
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Joseph J Walish
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Enrico Ravera
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM) University of Florence, 50019 Sesto Fiorentino (FI), Italy
| | - Claudio Luchinat
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM) University of Florence, 50019 Sesto Fiorentino (FI), Italy
| | - Timothy M Swager
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Robert G Griffin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
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23
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Debelouchina GT, Bayro MJ, Fitzpatrick AW, Ladizhansky V, Colvin MT, Caporini MA, Jaroniec CP, Bajaj VS, Rosay M, Macphee CE, Vendruscolo M, Maas WE, Dobson CM, Griffin RG. Higher order amyloid fibril structure by MAS NMR and DNP spectroscopy. J Am Chem Soc 2013; 135:19237-47. [PMID: 24304221 DOI: 10.1021/ja409050a] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Protein magic angle spinning (MAS) NMR spectroscopy has generated structural models of several amyloid fibril systems, thus providing valuable information regarding the forces and interactions that confer the extraordinary stability of the amyloid architecture. Despite these advances, however, obtaining atomic resolution information describing the higher levels of structural organization within the fibrils remains a significant challenge. Here, we detail MAS NMR experiments and sample labeling schemes designed specifically to probe such higher order amyloid structure, and we have applied them to the fibrils formed by an eleven-residue segment of the amyloidogenic protein transthyretin (TTR(105-115)). These experiments have allowed us to define unambiguously not only the arrangement of the peptide β-strands into β-sheets but also the β-sheet interfaces within each protofilament, and in addition to identify the nature of the protofilament-to-protofilament contacts that lead to the formation of the complete fibril. Our efforts have resulted in 111 quantitative distance and torsion angle restraints (10 per residue) that describe the various levels of structure organization. The experiments benefited extensively from the use of dynamic nuclear polarization (DNP), which in some cases allowed us to shorten the data acquisition time from days to hours and to improve significantly the signal-to-noise ratios of the spectra. The β-sheet interface and protofilament interactions identified here revealed local variations in the structure that result in multiple peaks for the exposed N- and C-termini of the peptide and in inhomogeneous line-broadening for the residues buried within the interior of the fibrils.
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Affiliation(s)
- Galia T Debelouchina
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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24
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Eddy MT, Belenky M, Sivertsen A, Griffin RG, Herzfeld J. Selectively dispersed isotope labeling for protein structure determination by magic angle spinning NMR. JOURNAL OF BIOMOLECULAR NMR 2013; 57:129-39. [PMID: 23990199 PMCID: PMC3793012 DOI: 10.1007/s10858-013-9773-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/16/2013] [Indexed: 05/18/2023]
Abstract
The power of nuclear magnetic resonance spectroscopy derives from its site-specific access to chemical, structural and dynamic information. However, the corresponding multiplicity of interactions can be difficult to tease apart. Complimentary approaches involve spectral editing on the one hand and selective isotope substitution on the other. Here we present a new "redox" approach to the latter: acetate is chosen as the sole carbon source for the extreme oxidation numbers of its two carbons. Consistent with conventional anabolic pathways for the amino acids, [1-(13)C] acetate does not label α carbons, labels other aliphatic carbons and the aromatic carbons very selectively, and labels the carboxyl carbons heavily. The benefits of this labeling scheme are exemplified by magic angle spinning spectra of microcrystalline immunoglobulin binding protein G (GB1): the elimination of most J-couplings and one- and two-bond dipolar couplings provides narrow signals and long-range, intra- and inter-residue, recoupling essential for distance constraints. Inverse redox labeling, from [2-(13)C] acetate, is also expected to be useful: although it retains one-bond couplings in the sidechains, the removal of CA-CO coupling in the backbone should improve the resolution of NCACX spectra.
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Affiliation(s)
- Matthew T. Eddy
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA
| | - Marina Belenky
- Department of Chemistry, Brandeis University, Waltham, MA
| | - Astrid Sivertsen
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA
- Department of Chemistry, Brandeis University, Waltham, MA
| | - Robert G. Griffin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA
| | - Judith Herzfeld
- Department of Chemistry, Brandeis University, Waltham, MA
- Corresponding author: , voice: 781-736-2538, fax: 781-736-2516
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Ni QZ, Daviso E, Can TV, Markhasin E, Jawla SK, Swager TM, Temkin RJ, Herzfeld J, Griffin RG. High frequency dynamic nuclear polarization. Acc Chem Res 2013; 46:1933-41. [PMID: 23597038 PMCID: PMC3778063 DOI: 10.1021/ar300348n] [Citation(s) in RCA: 390] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
During the three decades 1980-2010, magic angle spinning (MAS) NMR developed into the method of choice to examine many chemical, physical, and biological problems. In particular, a variety of dipolar recoupling methods to measure distances and torsion angles can now constrain molecular structures to high resolution. However, applications are often limited by the low sensitivity of the experiments, due in large part to the necessity of observing spectra of low-γ nuclei such as the I = 1/2 species (13)C or (15)N. The difficulty is still greater when quadrupolar nuclei, such as (17)O or (27)Al, are involved. This problem has stimulated efforts to increase the sensitivity of MAS experiments. A particularly powerful approach is dynamic nuclear polarization (DNP) which takes advantage of the higher equilibrium polarization of electrons (which conventionally manifests in the great sensitivity advantage of EPR over NMR). In DNP, the sample is doped with a stable paramagnetic polarizing agent and irradiated with microwaves to transfer the high polarization in the electron spin reservoir to the nuclei of interest. The idea was first explored by Overhauser and Slichter in 1953. However, these experiments were carried out on static samples, at magnetic fields that are low by current standards. To be implemented in contemporary MAS NMR experiments, DNP requires microwave sources operating in the subterahertz regime, roughly 150-660 GHz, and cryogenic MAS probes. In addition, improvements were required in the polarizing agents, because the high concentrations of conventional radicals that are required to produce significant enhancements compromise spectral resolution. In the last two decades, scientific and technical advances have addressed these problems and brought DNP to the point where it is achieving wide applicability. These advances include the development of high frequency gyrotron microwave sources operating in the subterahertz frequency range. In addition, low temperature MAS probes were developed that permit in situ microwave irradiation of the samples. And, finally, biradical polarizing agents were developed that increased the efficiency of DNP experiments by factors of ∼4 at considerably lower paramagnet concentrations. Collectively, these developments have made it possible to apply DNP on a routine basis to a number of different scientific endeavors, most prominently in the biological and material sciences. This Account reviews these developments, including the primary mechanisms used to transfer polarization in high frequency DNP, and the current choice of microwave sources and biradical polarizing agents. In addition, we illustrate the utility of the technique with a description of applications to membrane and amyloid proteins that emphasizes the unique structural information that is available in these two cases.
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Affiliation(s)
- Qing Zhe Ni
- Francis Bitter Magnet Laboratory, ‡Department of Chemistry, and §Plasma Science and Fusion Center, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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Yang S, Ravikumar KM, Levine H. Energy Evaluation of β-Strand Packing in a Fibril-Forming SH3 Domain. J Phys Chem B 2013; 117:13051-7. [DOI: 10.1021/jp402442p] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Sichun Yang
- Center for Proteomics and Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United
States
| | - Krishnakumar M. Ravikumar
- Center for Proteomics and Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United
States
| | - Herbert Levine
- Center for Theoretical
Biological Physics and Department of Bioengineering, Rice University, Houston, Texas, United States
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27
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Daviso E, Eddy MT, Andreas LB, Griffin RG, Herzfeld J. Efficient resonance assignment of proteins in MAS NMR by simultaneous intra- and inter-residue 3D correlation spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2013; 55:257-65. [PMID: 23334347 PMCID: PMC3615138 DOI: 10.1007/s10858-013-9707-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Accepted: 01/09/2013] [Indexed: 05/10/2023]
Abstract
Resonance assignment is the first step in NMR structure determination. For magic angle spinning NMR, this is typically achieved with a set of heteronuclear correlation experiments (NCaCX, NCOCX, CONCa) that utilize SPECIFIC-CP (15)N-(13)C transfers. However, the SPECIFIC-CP transfer efficiency is often compromised by molecular dynamics and probe performance. Here we show that one-bond ZF-TEDOR (15)N-(13)C transfers provide simultaneous NCO and NCa correlations with at least as much sensitivity as SPECIFIC-CP for some non-crystalline samples. Furthermore, a 3D ZF-TEDOR-CC experiment provides heteronuclear sidechain correlations and robustness with respect to proton decoupling and radiofrequency power instabilities. We demonstrate transfer efficiencies and connectivities by application of 3D ZF-TEDOR-DARR to a model microcrystalline protein, GB1, and a less ideal system, GvpA in intact gas vesicles.
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Affiliation(s)
- Eugenio Daviso
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, USA, 02454-9110
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 02139
| | - Matthew T. Eddy
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 02139
| | - Loren B. Andreas
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 02139
| | - Robert G. Griffin
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 02139
| | - Judith Herzfeld
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, USA, 02454-9110
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Jawla S, Ni QZ, Barnes A, Guss W, Daviso E, Herzfeld J, Griffin R, Temkin R. Continuously Tunable 250 GHz Gyrotron with a Double Disk Window for DNP-NMR Spectroscopy. JOURNAL OF INFRARED, MILLIMETER AND TERAHERTZ WAVES 2013; 34:42-52. [PMID: 23539422 PMCID: PMC3607393 DOI: 10.1007/s10762-012-9947-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In this paper, we describe the design and experimental results from the rebuild of a 250 GHz gyrotron used for Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance spectroscopy on a 380 MHz spectrometer. Tuning bandwidth of approximately 2 GHz is easily achieved at a fixed magnetic field of 9.24 T and a beam current of 95 mA producing an average output power of >10 W over the entire tuning band. This tube incorporates a double disk output sapphire window in order to maximize the transmission at 250.58 GHz. DNP Signal enhancement of >125 is achieved on a 13C-Urea sample using this gyrotron.
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Affiliation(s)
- Sudheer Jawla
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - Qing Zhe Ni
- Francis Bitter Magnet Lab and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - Alexander Barnes
- Francis Bitter Magnet Lab and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - William Guss
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - Eugenio Daviso
- Francis Bitter Magnet Lab and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
- Department of Chemistry, Brandies University, Waltham, MA-02454, USA
| | - Judith Herzfeld
- Department of Chemistry, Brandies University, Waltham, MA-02454, USA
| | - Robert Griffin
- Francis Bitter Magnet Lab and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - Richard Temkin
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
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Barnes AB, Markhasin E, Daviso E, Michaelis VK, Nanni EA, Jawla SK, Mena EL, DeRocher R, Thakkar A, Woskov PP, Herzfeld J, Temkin RJ, Griffin RG. Dynamic nuclear polarization at 700 MHz/460 GHz. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 224:1-7. [PMID: 23000974 PMCID: PMC3965575 DOI: 10.1016/j.jmr.2012.08.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 07/29/2012] [Accepted: 08/03/2012] [Indexed: 05/05/2023]
Abstract
We describe the design and implementation of the instrumentation required to perform DNP-NMR at higher field strengths than previously demonstrated, and report the first magic-angle spinning (MAS) DNP-NMR experiments performed at (1)H/e(-) frequencies of 700 MHz/460 GHz. The extension of DNP-NMR to 16.4 T has required the development of probe technology, cryogenics, gyrotrons, and microwave transmission lines. The probe contains a 460 GHz microwave channel, with corrugated waveguide, tapers, and miter-bends that couple microwave power to the sample. Experimental efficiency is increased by a cryogenic exchange system for 3.2 mm rotors within the 89 mm bore. Sample temperatures ≤85 K, resulting in improved DNP enhancements, are achieved by a novel heat exchanger design, stainless steel and brass vacuum jacketed transfer lines, and a bronze probe dewar. In addition, the heat exchanger is preceded with a nitrogen drying and generation system in series with a pre-cooling refrigerator. This reduces liquid nitrogen usage from >700 l per day to <200 l per day and allows for continuous (>7 days) cryogenic spinning without detrimental frost or ice formation. Initial enhancements, ε=-40, and a strong microwave power dependence suggests the possibility for considerable improvement. Finally, two-dimensional spectra of a model system demonstrate that the higher field provides excellent resolution, even in a glassy, cryoprotecting matrix.
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Affiliation(s)
- Alexander B Barnes
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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30
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Dasgupta A, Udgaonkar JB. Transient Non-Native Burial of a Trp Residue Occurs Initially during the Unfolding of a SH3 Domain. Biochemistry 2012; 51:8226-34. [DOI: 10.1021/bi3008627] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Amrita Dasgupta
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bangalore 560065,
India
| | - Jayant B. Udgaonkar
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bangalore 560065,
India
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31
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Paramasivam S, Suiter CL, Hou G, Sun S, Palmer M, Hoch JC, Rovnyak D, Polenova T. Enhanced sensitivity by nonuniform sampling enables multidimensional MAS NMR spectroscopy of protein assemblies. J Phys Chem B 2012; 116:7416-27. [PMID: 22667827 DOI: 10.1021/jp3032786] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We report dramatic sensitivity enhancements in multidimensional MAS NMR spectra by the use of nonuniform sampling (NUS) and introduce maximum entropy interpolation (MINT) processing that assures the linearity between the time and frequency domains of the NUS acquired data sets. A systematic analysis of sensitivity and resolution in 2D and 3D NUS spectra reveals that with NUS, at least 1.5- to 2-fold sensitivity enhancement can be attained in each indirect dimension without compromising the spectral resolution. These enhancements are similar to or higher than those attained by the newest-generation commercial cryogenic probes. We explore the benefits of this NUS/MaxEnt approach in proteins and protein assemblies using 1-73-(U-(13)C,(15)N)/74-108-(U-(15)N) Escherichia coli thioredoxin reassembly. We demonstrate that in thioredoxin reassembly, NUS permits acquisition of high-quality 3D-NCACX spectra, which are inaccessible with conventional sampling due to prohibitively long experiment times. Of critical importance, issues that hinder NUS-based SNR enhancement in 3D-NMR of liquids are mitigated in the study of solid samples in which theoretical enhancements on the order of 3-4 fold are accessible by compounding the NUS-based SNR enhancement of each indirect dimension. NUS/MINT is anticipated to be widely applicable and advantageous for multidimensional heteronuclear MAS NMR spectroscopy of proteins, protein assemblies, and other biological systems.
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Affiliation(s)
- Sivakumar Paramasivam
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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32
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Neudecker P, Robustelli P, Cavalli A, Walsh P, Lundström P, Zarrine-Afsar A, Sharpe S, Vendruscolo M, Kay LE. Structure of an intermediate state in protein folding and aggregation. Science 2012; 336:362-6. [PMID: 22517863 DOI: 10.1126/science.1214203] [Citation(s) in RCA: 305] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Protein-folding intermediates have been implicated in amyloid fibril formation involved in neurodegenerative disorders. However, the structural mechanisms by which intermediates initiate fibrillar aggregation have remained largely elusive. To gain insight, we used relaxation dispersion nuclear magnetic resonance spectroscopy to determine the structure of a low-populated, on-pathway folding intermediate of the A39V/N53P/V55L (A, Ala; V, Val; N, Asn; P, Pro; L, Leu) Fyn SH3 domain. The carboxyl terminus remains disordered in this intermediate, thereby exposing the aggregation-prone amino-terminal β strand. Accordingly, mutants lacking the carboxyl terminus and thus mimicking the intermediate fail to safeguard the folding route and spontaneously form fibrillar aggregates. The structure provides a detailed characterization of the non-native interactions stabilizing an aggregation-prone intermediate under native conditions and insight into how such an intermediate can derail folding and initiate fibrillation.
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Affiliation(s)
- Philipp Neudecker
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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33
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Jaroniec CP. Solid-state nuclear magnetic resonance structural studies of proteins using paramagnetic probes. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 43-44:1-13. [PMID: 22464402 DOI: 10.1016/j.ssnmr.2012.02.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 02/27/2012] [Accepted: 02/28/2012] [Indexed: 05/31/2023]
Abstract
Determination of three-dimensional structures of biological macromolecules by magic-angle spinning (MAS) solid-state NMR spectroscopy is hindered by the paucity of nuclear dipolar coupling-based restraints corresponding to distances exceeding 5 Å. Recent MAS NMR studies of uniformly (13)C,(15)N-enriched proteins containing paramagnetic centers have demonstrated the measurements of site-specific nuclear pseudocontact shifts and spin relaxation enhancements, which report on electron-nucleus distances up to ~20 Å. These studies pave the way for the application of such long-distance paramagnetic restraints to protein structure elucidation and analysis of protein-protein and protein-ligand interactions in the solid phase. Paramagnetic species also facilitate the rapid acquisition of high resolution and sensitivity multidimensional solid-state NMR spectra of biomacromolecules using condensed data collection schemes, and characterization of solvent-accessible surfaces of peptides and proteins. In this review we discuss some of the latest applications of magic-angle spinning NMR spectroscopy in conjunction with paramagnetic probes to the structural studies of proteins in the solid state.
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Affiliation(s)
- Christopher P Jaroniec
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA.
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34
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Moreau KL, King JA. Protein misfolding and aggregation in cataract disease and prospects for prevention. Trends Mol Med 2012; 18:273-82. [PMID: 22520268 DOI: 10.1016/j.molmed.2012.03.005] [Citation(s) in RCA: 288] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/01/2012] [Accepted: 03/14/2012] [Indexed: 11/16/2022]
Abstract
The transparency of the eye lens depends on maintaining the native tertiary structures and solubility of the lens crystallin proteins over a lifetime. Cataract, the leading cause of blindness worldwide, is caused by protein aggregation within the protected lens environment. With age, covalent protein damage accumulates through pathways thought to include UV radiation, oxidation, deamidation, and truncations. Experiments suggest that the resulting protein destabilization leads to partially unfolded, aggregation-prone intermediates and the formation of insoluble, light-scattering protein aggregates. These aggregates either include or overwhelm the protein chaperone content of the lens. Here, we review the causes of cataract and nonsurgical methods being investigated to inhibit or delay cataract development, including natural product-based therapies, modulators of oxidation, and protein aggregation inhibitors.
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Affiliation(s)
- Kate L Moreau
- Massachusetts Institute of Technology, Department of Biology, 77 Massachusetts Avenue, 68-330, Cambridge, MA 02139, USA
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35
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Forman CJ, Nickson AA, Anthony-Cahill SJ, Baldwin AJ, Kaggwa G, Feber U, Sheikh K, Jarvis SP, Barker PD. The morphology of decorated amyloid fibers is controlled by the conformation and position of the displayed protein. ACS NANO 2012; 6:1332-1346. [PMID: 22276813 DOI: 10.1021/nn204140a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Self-assembled structures capable of mediating electron transfer are an attractive scientific and technological goal. Therefore, systematic variants of SH3-Cytochrome b(562) fusion proteins were designed to make amyloid fibers displaying heme-b(562) electron transfer complexes. TEM and AFM data show that fiber morphology responds systematically to placement of b(562) within the fusion proteins. UV-vis spectroscopy shows that, for the fusion proteins under test, only half the fiber-borne b(562) binds heme with high affinity. Cofactor binding also improves the AFM imaging properties and changes the fiber morphology through changes in cytochrome conformation. Systematic observations and measurements of fiber geometry suggest that longitudinal registry of subfilaments within the fiber, mediated by the interaction and conformation of the displayed proteins and their interaction with surfaces, gives rise to the observed morphologies, including defects and kinks. Of most interest is the role of small molecule modulation of fiber structure and mechanical stability. A minimum complexity model is proposed to capture and explain the fiber morphology in the light of these results. Understanding the complex interplay between these factors will enable a fiber design that supports longitudinal electron transfer.
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Affiliation(s)
- Christopher J Forman
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
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36
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Graña-Montes R, de Groot NS, Castillo V, Sancho J, Velazquez-Campoy A, Ventura S. Contribution of disulfide bonds to stability, folding, and amyloid fibril formation: the PI3-SH3 domain case. Antioxid Redox Signal 2012; 16:1-15. [PMID: 21797671 DOI: 10.1089/ars.2011.3936] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS The failure of proteins to fold or to remain folded very often leads to their deposition into amyloid fibrils and is the origin of a variety of human diseases. Accordingly, mutations that destabilize the native conformation are associated with pathological phenotypes in several protein models. Protein backbone cyclization by disulfide bond crosslinking strongly reduces the entropy of the unfolded state and, usually, increases protein stability. The effect of protein cyclization on the thermodynamic and kinetics of folding has been extensively studied, but little is know on its effect on aggregation reactions. RESULTS The SRC homology 3 domain (SH3) of p85α subunit of bovine phosphatidyl-inositol-3'-kinase (PI3-SH3) domain is a small globular protein, whose folding and amyloid properties are well characterized. Here we describe the effect of polypeptide backbone cyclization on both processes. INNOVATION We show that a cyclized PI3-SH3 variant is more stable, folds faster, aggregates slower, and forms conformationally and functionally different amyloid fibrils than the wild-type domain. CONCLUSION Disulfide bridges may act as key molecular determinants of both productive protein folding and deleterious aggregation reactions.
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Affiliation(s)
- Ricardo Graña-Montes
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Bayro MJ, Daviso E, Belenky M, Griffin RG, Herzfeld J. An amyloid organelle, solid-state NMR evidence for cross-β assembly of gas vesicles. J Biol Chem 2011; 287:3479-84. [PMID: 22147705 DOI: 10.1074/jbc.m111.313049] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Functional amyloids have been identified in a wide range of organisms, taking on a variety of biological roles and being controlled by remarkable mechanisms of directed assembly. Here, we report that amyloid fibrils constitute the ribs of the buoyancy organelles of Anabaena flos-aquae. The walls of these gas-filled vesicles are known to comprise a single protein, GvpA, arranged in a low pitch helix. However, the tertiary and quaternary structures have been elusive. Using solid-state NMR correlation spectroscopy we find detailed evidence for an extended cross-β structure. This amyloid assembly helps to account for the strength and amphiphilic properties of the vesicle wall. Buoyancy organelles thus dramatically extend the scope of known functional amyloids.
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Affiliation(s)
- Marvin J Bayro
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Abstract
Amyloid-beta (Aβ) aggregates are the main constituent of senile plaques, the histological hallmark of Alzheimer's disease. Aβ molecules form β-sheet containing structures that assemble into a variety of polymorphic oligomers, protofibers, and fibers that exhibit a range of lifetimes and cellular toxicities. This polymorphic nature of Aβ has frustrated its biophysical characterization, its structural determination, and our understanding of its pathological mechanism. To elucidate Aβ polymorphism in atomic detail, we determined eight new microcrystal structures of fiber-forming segments of Aβ. These structures, all of short, self-complementing pairs of β-sheets termed steric zippers, reveal a variety of modes of self-association of Aβ. Combining these atomic structures with previous NMR studies allows us to propose several fiber models, offering molecular models for some of the repertoire of polydisperse structures accessible to Aβ. These structures and molecular models contribute fundamental information for understanding Aβ polymorphic nature and pathogenesis.
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39
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Bertini I, Gonnelli L, Luchinat C, Mao J, Nesi A. A new structural model of Aβ40 fibrils. J Am Chem Soc 2011; 133:16013-22. [PMID: 21882806 DOI: 10.1021/ja2035859] [Citation(s) in RCA: 263] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The amyloid fibrils of beta-amyloid (Aβ) peptides play important roles in the pathology of Alzheimer's disease. Comprehensive solid-state NMR (SSNMR) structural studies on uniformly isotope-labeled Aβ assemblies have been hampered for a long time by sample heterogeneity and low spectral resolution. In this work, SSNMR studies on well-ordered fibril samples of Aβ(40) with an additional N-terminal methionine provide high-resolution spectra which lead to an accurate structural model. The fibrils studied here carry distinct structural features compared to previous reports. The inter-β-strand contacts within the U-shaped β-strand-turn-β-strand motif are shifted, the N-terminal region adopts a β-conformation, and new inter-monomer contacts occur at the protofilament interface. The revealed structural diversity in Aβ fibrils points to a complex picture of Aβ fibrillation.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
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40
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Bayro MJ, Debelouchina GT, Eddy MT, Birkett NR, MacPhee CE, Rosay M, Maas WE, Dobson CM, Griffin RG. Intermolecular structure determination of amyloid fibrils with magic-angle spinning and dynamic nuclear polarization NMR. J Am Chem Soc 2011; 133:13967-74. [PMID: 21774549 DOI: 10.1021/ja203756x] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We describe magic-angle spinning NMR experiments designed to elucidate the interstrand architecture of amyloid fibrils. Three methods are introduced for this purpose, two being based on the analysis of long-range (13)C-(13)C correlation spectra and the third based on the identification of intermolecular interactions in (13)C-(15)N spectra. We show, in studies of fibrils formed by the 86-residue SH3 domain of PI3 kinase (PI3-SH3 or PI3K-SH3), that efficient (13)C-(13)C correlation spectra display a resonance degeneracy that establishes a parallel, in-register alignment of the proteins in the amyloid fibrils. In addition, this degeneracy can be circumvented to yield direct intermolecular constraints. The (13)C-(13)C experiments are corroborated by (15)N-(13)C correlation spectra obtained from a mixed [(15)N,(12)C]/[(14)N,(13)C] sample which directly quantify interstrand distances. Furthermore, when the spectra are recorded with signal enhancement provided by dynamic nuclear polarization (DNP) at 100 K, we demonstrate a dramatic increase (from 23 to 52) in the number of intermolecular (15)N-(13)C constraints detectable in the spectra. The increase in the information content is due to the enhanced signal intensities and to the fact that dynamic processes, leading to spectral intensity losses, are quenched at low temperatures. Thus, acquisition of low temperature spectra addresses a problem that is frequently encountered in MAS spectra of proteins. In total, the experiments provide 111 intermolecular (13)C-(13)C and (15)N-(13)C constraints that establish that the PI3-SH3 protein strands are aligned in a parallel, in-register arrangement within the amyloid fibril.
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Affiliation(s)
- Marvin J Bayro
- Francis Bitter Magnet Laboratory, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, 02139, United States
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Lin EC, Opella SJ. 1H assisted 13C/15N heteronuclear correlation spectroscopy in oriented sample solid-state NMR of single crystal and magnetically aligned samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 211:37-44. [PMID: 21543244 PMCID: PMC3236683 DOI: 10.1016/j.jmr.2011.03.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Revised: 03/23/2011] [Accepted: 03/29/2011] [Indexed: 05/30/2023]
Abstract
(1)H-irradiation under mismatched Hartmann-Hahn conditions provides an alternative mechanism for carrying out (15)N/(13)C transfers in triple-resonance heteronuclear correlation spectroscopy (HETCOR) on stationary samples of single crystals and aligned samples of biopolymers, which improve the efficiency especially when the direct (15)N-(13)C dipolar couplings are small. In many cases, the sensitivity is improved by taking advantage of the (13)C(α) labeled sites in peptides and proteins with (13)C detection. The similarities between experimental and simulated spectra demonstrate the validity of the recoupling mechanism and identify the potential for applying these experiments to virus particles or membrane proteins in phospholipid bilayers; however, further development is needed in order to derive quantitative distance and angular constraints from these measurements.
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Affiliation(s)
| | - Stanley J. Opella
- Corresponding Author: Stanley J. Opella, , phone 858 822-4820, FAX 858 822-4821
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Landau M, Sawaya MR, Faull KF, Laganowsky A, Jiang L, Sievers SA, Liu J, Barrio JR, Eisenberg D. Towards a pharmacophore for amyloid. PLoS Biol 2011; 9:e1001080. [PMID: 21695112 PMCID: PMC3114762 DOI: 10.1371/journal.pbio.1001080] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 04/29/2011] [Indexed: 12/30/2022] Open
Abstract
Diagnosing and treating Alzheimer's and other diseases associated with amyloid fibers remains a great challenge despite intensive research. To aid in this effort, we present atomic structures of fiber-forming segments of proteins involved in Alzheimer's disease in complex with small molecule binders, determined by X-ray microcrystallography. The fiber-like complexes consist of pairs of β-sheets, with small molecules binding between the sheets, roughly parallel to the fiber axis. The structures suggest that apolar molecules drift along the fiber, consistent with the observation of nonspecific binding to a variety of amyloid proteins. In contrast, negatively charged orange-G binds specifically to lysine side chains of adjacent sheets. These structures provide molecular frameworks for the design of diagnostics and drugs for protein aggregation diseases. The devastating and incurable dementia known as Alzheimer's disease affects the thinking, memory, and behavior of dozens of millions of people worldwide. Although amyloid fibers and oligomers of two proteins, tau and amyloid-β, have been identified in association with this disease, the development of diagnostics and therapeutics has proceeded to date in a near vacuum of information about their structures. Here we report the first atomic structures of small molecules bound to amyloid. These are of the dye orange-G, the natural compound curcumin, and the Alzheimer's diagnostic compound DDNP bound to amyloid-like segments of tau and amyloid-β. The structures reveal the molecular framework of small-molecule binding, within cylindrical cavities running along the β-spines of the fibers. Negatively charged orange-G wedges into a specific binding site between two sheets of the fiber, combining apolar binding with electrostatic interactions, whereas uncharged compounds slide along the cavity. We observed that different amyloid polymorphs bind different small molecules, revealing that a cocktail of compounds may be required for future amyloid therapies. The structures described here start to define the amyloid pharmacophore, opening the way to structure-based design of improved diagnostics and therapeutics.
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Affiliation(s)
- Meytal Landau
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Departments of Biological Chemistry and Chemistry and Biochemistry, University of California, Los Angeles, California, United States of America
| | - Michael R. Sawaya
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Departments of Biological Chemistry and Chemistry and Biochemistry, University of California, Los Angeles, California, United States of America
| | - Kym F. Faull
- The Pasarow Mass Spectrometry Laboratory, The NPI-Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Arthur Laganowsky
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Departments of Biological Chemistry and Chemistry and Biochemistry, University of California, Los Angeles, California, United States of America
| | - Lin Jiang
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Departments of Biological Chemistry and Chemistry and Biochemistry, University of California, Los Angeles, California, United States of America
| | - Stuart A. Sievers
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Departments of Biological Chemistry and Chemistry and Biochemistry, University of California, Los Angeles, California, United States of America
| | - Jie Liu
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Jorge R. Barrio
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - David Eisenberg
- Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Departments of Biological Chemistry and Chemistry and Biochemistry, University of California, Los Angeles, California, United States of America
- * E-mail:
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Nanni EA, Barnes AB, Matsuki Y, Woskov PP, Corzilius B, Griffin RG, Temkin RJ. Microwave field distribution in a magic angle spinning dynamic nuclear polarization NMR probe. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 210:16-23. [PMID: 21382733 PMCID: PMC3081422 DOI: 10.1016/j.jmr.2011.02.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 02/01/2011] [Accepted: 02/01/2011] [Indexed: 05/05/2023]
Abstract
We present a calculation of the microwave field distribution in a magic angle spinning (MAS) probe utilized in dynamic nuclear polarization (DNP) experiments. The microwave magnetic field (B(1S)) profile was obtained from simulations performed with the High Frequency Structure Simulator (HFSS) software suite, using a model that includes the launching antenna, the outer Kel-F stator housing coated with Ag, the RF coil, and the 4mm diameter sapphire rotor containing the sample. The predicted average B(1S) field is 13μT/W(1/2), where S denotes the electron spin. For a routinely achievable input power of 5W the corresponding value is γ(S)B(1S)=0.84MHz. The calculations provide insights into the coupling of the microwave power to the sample, including reflections from the RF coil and diffraction of the power transmitted through the coil. The variation of enhancement with rotor wall thickness was also successfully simulated. A second, simplified calculation was performed using a single pass model based on Gaussian beam propagation and Fresnel diffraction. This model provided additional physical insight and was in good agreement with the full HFSS simulation. These calculations indicate approaches to increasing the coupling of the microwave power to the sample, including the use of a converging lens and fine adjustment of the spacing of the windings of the RF coil. The present results should prove useful in optimizing the coupling of microwave power to the sample in future DNP experiments. Finally, the results of the simulation were used to predict the cross effect DNP enhancement (ϵ) vs. ω(1S)/(2π) for a sample of (13)C-urea dissolved in a 60:40 glycerol/water mixture containing the polarizing agent TOTAPOL; very good agreement was obtained between theory and experiment.
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Affiliation(s)
- Emilio A Nanni
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Corzilius B, Smith AA, Barnes AB, Luchinat C, Bertini I, Griffin RG. High-field dynamic nuclear polarization with high-spin transition metal ions. J Am Chem Soc 2011; 133:5648-51. [PMID: 21446700 PMCID: PMC3086350 DOI: 10.1021/ja1109002] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the dynamic nuclear polarization of (1)H spins in magic-angle-spinning spectra recorded at 5 T and 84 K via the solid effect using Mn(2+) and Gd(3+) complexes as polarizing agents. We show that the magnitude of the enhancements can be directly related to the effective line width of the central (m(S) = -1/2 → +1/2) EPR transition. Using a Gd(3+) complex with a narrow central transition EPR line width of 29 MHz, we observed a maximum enhancement of ∼13, which is comparable to previous results on the narrow-line-width trityl radical.
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Affiliation(s)
- Björn Corzilius
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Albert A. Smith
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Alexander B. Barnes
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Claudio Luchinat
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
| | - Ivano Bertini
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
| | - Robert G. Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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45
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Chan JCC. Solid-state NMR techniques for the structural determination of amyloid fibrils. Top Curr Chem (Cham) 2011; 306:47-88. [PMID: 21630137 DOI: 10.1007/128_2011_154] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This review discusses the solid-state NMR techniques developed for the study of amyloid fibrils. Literature up to the end of 2010 has been surveyed and the materials are organized according to five categories, viz. homonuclear dipolar recoupling and polarization transfer via J-coupling, heteronuclear dipolar recoupling, correlation spectroscopy, recoupling of chemical shift anisotropy, and tensor correlation. Our emphasis is on the NMR techniques and their practical aspects. The biological implications of the results obtained for amyloid fibrils are only briefly discussed. Our main objective is to showcase the power of NMR in the study of biological unoriented solids.
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Affiliation(s)
- Jerry C C Chan
- Department of Chemistry, National Taiwan University, Taipei, Taiwan.
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46
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Debelouchina GT, Platt GW, Bayro MJ, Radford SE, Griffin RG. Intermolecular alignment in β2-microglobulin amyloid fibrils. J Am Chem Soc 2010. [PMID: 21077676 DOI: 10.1021/ja1079871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
The deposition of amyloid-like fibrils, composed primarily of the 99-residue protein β2-microglobulin (β2m), is one of the characteristic symptoms of dialysis-related amyloidosis. Fibrils formed in vitro at low pH and low salt concentration share many properties with the disease related fibrils and have been extensively studied by a number of biochemical and biophysical methods. These fibrils contain a significant β-sheet core and have a complex cryoEM electron density profile. Here, we investigate the intrasheet arrangement of the fibrils by means of (15)N-(13)C MAS NMR correlation spectroscopy. We utilize a fibril sample grown from a 50:50 mixture of (15)N,(12)C- and (14)N,(13)C-labeled β2m monomers, the latter prepared using 2-(13)C glycerol as the carbon source. Together with the use of ZF-TEDOR mixing, this sample allowed us to observe intermolecular (15)N-(13)C backbone-to-backbone contacts with excellent resolution and good sensitivity. The results are consistent with a parallel, in-register arrangement of the protein subunits in the fibrils and suggest that a significant structural reorganization occurs from the native to the fibril state.
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Affiliation(s)
- Galia T Debelouchina
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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47
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Debelouchina GT, Platt GW, Bayro MJ, Radford SE, Griffin RG. Intermolecular alignment in β2-microglobulin amyloid fibrils. J Am Chem Soc 2010; 132:17077-9. [PMID: 21077676 PMCID: PMC2996106 DOI: 10.1021/ja107987f] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2010] [Indexed: 11/29/2022]
Abstract
The deposition of amyloid-like fibrils, composed primarily of the 99-residue protein β2-microglobulin (β2m), is one of the characteristic symptoms of dialysis-related amyloidosis. Fibrils formed in vitro at low pH and low salt concentration share many properties with the disease related fibrils and have been extensively studied by a number of biochemical and biophysical methods. These fibrils contain a significant β-sheet core and have a complex cryoEM electron density profile. Here, we investigate the intrasheet arrangement of the fibrils by means of (15)N-(13)C MAS NMR correlation spectroscopy. We utilize a fibril sample grown from a 50:50 mixture of (15)N,(12)C- and (14)N,(13)C-labeled β2m monomers, the latter prepared using 2-(13)C glycerol as the carbon source. Together with the use of ZF-TEDOR mixing, this sample allowed us to observe intermolecular (15)N-(13)C backbone-to-backbone contacts with excellent resolution and good sensitivity. The results are consistent with a parallel, in-register arrangement of the protein subunits in the fibrils and suggest that a significant structural reorganization occurs from the native to the fibril state.
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Affiliation(s)
- Galia T Debelouchina
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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