1
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Nimerovsky E, Varkey AC, Kim M, Becker S, Andreas LB. Simplified Preservation of Equivalent Pathways Spectroscopy. JACS AU 2023; 3:2763-2771. [PMID: 37885577 PMCID: PMC10598565 DOI: 10.1021/jacsau.3c00312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/28/2023]
Abstract
Inspired by the recently proposed transverse mixing optimal control pulses (TROP) approach for improving signal in multidimensional magic-angle spinning (MAS) NMR experiments, we present simplified preservation of equivalent pathways spectroscopy (SPEPS). It transfers both transverse components of magnetization that occur during indirect evolutions, theoretically enabling a √2 improvement in sensitivity for each such dimension. We compare SPEPS transfer with TROP and cross-polarization (CP) using membrane protein and fibril samples at MAS of 55 and 100 kHz. In three-dimensional (3D) (H)CANH spectra, SPEPS outperformed TROP and CP by factors of on average 1.16 and 1.69, respectively, for the membrane protein, but only a marginal improvement of 1.09 was observed for the fibril. These differences are discussed, making note of the longer transfer time used for CP, 14 ms, as compared with 2.9 and 3.6 ms for SPEPS and TROP, respectively. Using SPEPS for two transfers in the 3D (H)CANCO experiment resulted in an even larger benefit in signal intensity, with an average improvement of 1.82 as compared with CP. This results in multifold time savings, in particular considering the weaker peaks that are observed to benefit the most from SPEPS.
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Affiliation(s)
- Evgeny Nimerovsky
- Department of NMR based Structural
Biology, Max Planck Institute for Multidisciplinary
Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Abel Cherian Varkey
- Department of NMR based Structural
Biology, Max Planck Institute for Multidisciplinary
Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Myeongkyu Kim
- Department of NMR based Structural
Biology, Max Planck Institute for Multidisciplinary
Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Stefan Becker
- Department of NMR based Structural
Biology, Max Planck Institute for Multidisciplinary
Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Loren B. Andreas
- Department of NMR based Structural
Biology, Max Planck Institute for Multidisciplinary
Sciences, Am Fassberg 11, Göttingen 37077, Germany
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2
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Sundaria A, Liberta F, Savran D, Sarkar R, Rodina N, Peters C, Schwierz N, Haupt C, Schmidt M, Reif B. SAA fibrils involved in AA amyloidosis are similar in bulk and by single particle reconstitution: A MAS solid-state NMR study. J Struct Biol X 2022; 6:100069. [PMID: 35924280 PMCID: PMC9340516 DOI: 10.1016/j.yjsbx.2022.100069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 07/09/2022] [Accepted: 07/15/2022] [Indexed: 11/25/2022] Open
Abstract
AA amyloidosis is one of the most prevalent forms of systemic amyloidosis and affects both humans and other vertebrates. In this study, we compare MAS solid-state NMR data with a recent cryo-EM study of fibrils involving full-length murine SAA1.1. We address the question whether the specific requirements for the reconstitution of an amyloid fibril structure by cryo-EM can potentially yield a bias towards a particular fibril polymorph. We employ fibril seeds extracted from in to vivo material to imprint the fibril structure onto the biochemically produced protein. Sequential assignments yield the secondary structure elements in the fibril state. Long-range DARR and PAR experiments confirm largely the topology observed in the ex-vivo cryo-EM study. We find that the β-sheets identified in the NMR experiments are similar to the β-sheets found in the cryo-EM study, with the exception of amino acids 33–42. These residues cannot be assigned by solid-state NMR, while they adopt a stable β-sheet in the cryo-EM structure. We suggest that the differences between MAS solid-state NMR and cryo-EM data are a consequence of a second conformer involving residues 33–42. Moreover, we were able to characterize the dynamic C-terminal tail of SAA in the fibril state. The C-terminus is flexible, remains detached from the fibrils, and does not affect the SAA fibril structure as confirmed further by molecular dynamics simulations. As the C-terminus can potentially interact with other cellular components, binding to cellular targets can affect its accessibility for protease digestion.
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3
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Pérez-Conesa S, Keeler EG, Zhang D, Delemotte L, McDermott AE. Informing NMR experiments with molecular dynamics simulations to characterize the dominant activated state of the KcsA ion channel. J Chem Phys 2021; 154:165102. [PMID: 33940802 PMCID: PMC9250420 DOI: 10.1063/5.0040649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
As the first potassium channel with an x-ray structure determined, and given its homology to eukaryotic channels, the pH-gated prokaryotic channel KcsA has been extensively studied. Nevertheless, questions related, in particular, to the allosteric coupling between its gates remain open. The many currently available x-ray crystallography structures appear to correspond to various stages of activation and inactivation, offering insights into the molecular basis of these mechanisms. Since these studies have required mutations, complexation with antibodies, and substitution of detergents in place of lipids, examining the channel under more native conditions is desirable. Solid-state nuclear magnetic resonance (SSNMR) can be used to study the wild-type protein under activating conditions (low pH), at room temperature, and in bacteriomimetic liposomes. In this work, we sought to structurally assign the activated state present in SSNMR experiments. We used a combination of molecular dynamics (MD) simulations, chemical shift prediction algorithms, and Bayesian inference techniques to determine which of the most plausible x-ray structures resolved to date best represents the activated state captured in SSNMR. We first identified specific nuclei with simulated NMR chemical shifts that differed significantly when comparing partially open vs fully open ensembles from MD simulations. The simulated NMR chemical shifts for those specific nuclei were then compared to experimental ones, revealing that the simulation of the partially open state was in good agreement with the SSNMR data. Nuclei that discriminate effectively between partially and fully open states belong to residues spread over the sequence and provide a molecular level description of the conformational change.
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Affiliation(s)
- Sergio Pérez-Conesa
- KTH Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
| | - Eric G Keeler
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Dongyu Zhang
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Lucie Delemotte
- KTH Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
| | - Ann E McDermott
- Department of Chemistry, Columbia University, New York, New York 10027, USA
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4
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Pradhan T, Annamalai K, Sarkar R, Hegenbart U, Schönland S, Fändrich M, Reif B. Solid state NMR assignments of a human λ-III immunoglobulin light chain amyloid fibril. BIOMOLECULAR NMR ASSIGNMENTS 2021; 15:9-16. [PMID: 32946005 PMCID: PMC7973639 DOI: 10.1007/s12104-020-09975-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/11/2020] [Indexed: 05/09/2023]
Abstract
The aggregation of antibody light chains is linked to systemic light chain (AL) amyloidosis, a disease where amyloid deposits frequently affect the heart and the kidney. We here investigate fibrils from the λ-III FOR005 light chain (LC), which is derived from an AL-patient with severe cardiac involvement. In FOR005, five residues are mutated with respect to its closest germline gene segment IGLV3-19 and IGLJ3. All mutations are located close to the complementarity determining regions (CDRs). The sequence segments responsible for the fibril formation are not yet known. We use fibrils extracted from the heart of this particular amyloidosis patient as seeds to prepare fibrils for solid-state NMR. We show that the seeds induce the formation of a specific fibril structure from the biochemically produced protein. We have assigned the fibril core region of the FOR005-derived fibrils and characterized the secondary structure propensity of the observed amino acids. As the primary structure of the aggregated patient protein is different for every AL patient, it is important to study, analyze and report a greater number of light chain sequences associated with AL amyloidosis.
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Affiliation(s)
- Tejaswini Pradhan
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit Und Umwelt, Institute of Structural Biology, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
- Department of Chemistry, Munich Center for Integrated Protein Science (CIPS-M), Technische Universität München (TUM), Lichtenbergstr. 4, 85747, Garching, Germany
| | - Karthikeyan Annamalai
- Institute of Protein Biochemistry, Ulm University, Helmholtzstrasse 8/1, 89081, Ulm, Germany
| | - Riddhiman Sarkar
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit Und Umwelt, Institute of Structural Biology, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
- Department of Chemistry, Munich Center for Integrated Protein Science (CIPS-M), Technische Universität München (TUM), Lichtenbergstr. 4, 85747, Garching, Germany
| | - Ute Hegenbart
- Medical Department V, Amyloidosis Center, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Stefan Schönland
- Medical Department V, Amyloidosis Center, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Marcus Fändrich
- Institute of Protein Biochemistry, Ulm University, Helmholtzstrasse 8/1, 89081, Ulm, Germany
| | - Bernd Reif
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit Und Umwelt, Institute of Structural Biology, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.
- Department of Chemistry, Munich Center for Integrated Protein Science (CIPS-M), Technische Universität München (TUM), Lichtenbergstr. 4, 85747, Garching, Germany.
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5
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Pradhan T, Annamalai K, Sarkar R, Huhn S, Hegenbart U, Schönland S, Fändrich M, Reif B. Seeded fibrils of the germline variant of human λ-III immunoglobulin light chain FOR005 have a similar core as patient fibrils with reduced stability. J Biol Chem 2020; 295:18474-18484. [PMID: 33093170 PMCID: PMC7939468 DOI: 10.1074/jbc.ra120.016006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/21/2020] [Indexed: 11/26/2022] Open
Abstract
Systemic antibody light chains (AL) amyloidosis is characterized by deposition of amyloid fibrils derived from a particular antibody light chain. Cardiac involvement is a major risk factor for mortality. Using MAS solid-state NMR, we studied the fibril structure of a recombinant light chain fragment corresponding to the fibril protein from patient FOR005, together with fibrils formed by protein sequence variants that are derived from the closest germline (GL) sequence. Both analyzed fibril structures were seeded with ex-vivo amyloid fibrils purified from the explanted heart of this patient. We find that residues 11-42 and 69-102 adopt β-sheet conformation in patient protein fibrils. We identify arginine-49 as a key residue that forms a salt bridge to aspartate-25 in the patient protein fibril structure. In the germline sequence, this residue is replaced by a glycine. Fibrils from the GL protein and from the patient protein harboring the single point mutation R49G can be both heterologously seeded using patient ex-vivo fibrils. Seeded R49G fibrils show an increased heterogeneity in the C-terminal residues 80-102, which is reflected by the disappearance of all resonances of these residues. By contrast, residues 11-42 and 69-77, which are visible in the MAS solid-state NMR spectra, show 13Cα chemical shifts that are highly like patient fibrils. The mutation R49G thus induces a conformational heterogeneity at the C terminus in the fibril state, whereas the overall fibril topology is retained. These findings imply that patient mutations in FOR005 can stabilize the fibril structure.
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Affiliation(s)
- Tejaswini Pradhan
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit und UmweltInstitute of Structural Biology (STB), Neuherberg, Germany; Munich Center for Integrated Protein Science (CIPS-M) at the Dept. of Chemistry, Technische Universität München (TUM), Garching, Germany
| | | | - Riddhiman Sarkar
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit und UmweltInstitute of Structural Biology (STB), Neuherberg, Germany; Munich Center for Integrated Protein Science (CIPS-M) at the Dept. of Chemistry, Technische Universität München (TUM), Garching, Germany
| | - Stefanie Huhn
- Medical Department V, Multiple Myeloma Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Ute Hegenbart
- Medical Department V, Amyloidosis Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Stefan Schönland
- Medical Department V, Amyloidosis Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Marcus Fändrich
- Institute of Protein Biochemistry, Ulm University, Ulm, Germany
| | - Bernd Reif
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit und UmweltInstitute of Structural Biology (STB), Neuherberg, Germany; Munich Center for Integrated Protein Science (CIPS-M) at the Dept. of Chemistry, Technische Universität München (TUM), Garching, Germany.
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6
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Kaur H, Grahl A, Hartmann JB, Hiller S. Sample Preparation and Technical Setup for NMR Spectroscopy with Integral Membrane Proteins. Methods Mol Biol 2020; 2127:373-396. [PMID: 32112334 DOI: 10.1007/978-1-0716-0373-4_24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
NMR spectroscopy is a method of choice to characterize structure, function, and dynamics of integral membrane proteins at atomic resolution. Here, we describe protocols for sample preparation and characterization by NMR spectroscopy of two integral membrane proteins with different architecture, the α-helical membrane protein MsbA and the β-barrel membrane protein BamA. The protocols describe recombinant expression in E. coli, protein refolding, purification, and reconstitution in suitable membrane mimetics, as well as key setup steps for basic NMR experiments. These include experiments on protein samples in the solid state under magic angle spinning (MAS) conditions and experiments on protein samples in aqueous solution. Since MsbA and BamA are typical examples of their respective architectural classes, the protocols presented here can also serve as a reference for other integral membrane proteins.
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Affiliation(s)
- Hundeep Kaur
- Biozentrum, University of Basel, Basel, Switzerland
| | - Anne Grahl
- Biozentrum, University of Basel, Basel, Switzerland
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7
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Demers JP, Fricke P, Shi C, Chevelkov V, Lange A. Structure determination of supra-molecular assemblies by solid-state NMR: Practical considerations. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:51-78. [PMID: 30527136 DOI: 10.1016/j.pnmrs.2018.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/15/2018] [Accepted: 06/15/2018] [Indexed: 05/26/2023]
Abstract
In the cellular environment, biomolecules assemble in large complexes which can act as molecular machines. Determining the structure of intact assemblies can reveal conformations and inter-molecular interactions that are only present in the context of the full assembly. Solid-state NMR (ssNMR) spectroscopy is a technique suitable for the study of samples with high molecular weight that allows the atomic structure determination of such large protein assemblies under nearly physiological conditions. This review provides a practical guide for the first steps of studying biological supra-molecular assemblies using ssNMR. The production of isotope-labeled samples is achievable via several means, which include recombinant expression, cell-free protein synthesis, extraction of assemblies directly from cells, or even the study of assemblies in whole cells in situ. Specialized isotope labeling schemes greatly facilitate the assignment of chemical shifts and the collection of structural data. Advanced strategies such as mixed, diluted, or segmental subunit labeling offer the possibility to study inter-molecular interfaces. Detailed and practical considerations are presented with respect to first setting up magic-angle spinning (MAS) ssNMR experiments, including the selection of the ssNMR rotor, different methods to best transfer the sample and prepare the rotor, as well as common and robust procedures for the calibration of the instrument. Diagnostic spectra to evaluate the resolution and sensitivity of the sample are presented. Possible improvements that can reduce sample heterogeneity and improve the quality of ssNMR spectra are reviewed.
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Affiliation(s)
- Jean-Philippe Demers
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Laboratory of Cell Biology, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Pascal Fricke
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Chaowei Shi
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Veniamin Chevelkov
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
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8
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Higman VA. Solid-state MAS NMR resonance assignment methods for proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 106-107:37-65. [PMID: 31047601 DOI: 10.1016/j.pnmrs.2018.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/19/2018] [Accepted: 04/24/2018] [Indexed: 06/09/2023]
Abstract
The prerequisite to structural or functional studies of proteins by NMR is generally the assignment of resonances. Since the first assignment of proteins by solid-state MAS NMR was conducted almost two decades ago, a wide variety of different pulse sequences and methods have been proposed and continue to be developed. Traditionally, a variety of 2D and 3D 13C-detected experiments have been used for the assignment of backbone and side-chain 13C and 15N resonances. These methods have found widespread use across the field. But as the hardware has changed and higher spinning frequencies and magnetic fields are becoming available, the ability to use direct proton detection is opening up a new set of assignment methods based on triple-resonance experiments. This review describes solid-state MAS NMR assignment methods using carbon detection and proton detection at different deuteration levels. The use of different isotopic labelling schemes as an aid to assignment in difficult cases is discussed as well as the increasing number of software packages that support manual and automated resonance assignment.
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Affiliation(s)
- Victoria A Higman
- Department of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TU, UK.
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9
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Chipot C, Dehez F, Schnell JR, Zitzmann N, Pebay-Peyroula E, Catoire LJ, Miroux B, Kunji ERS, Veglia G, Cross TA, Schanda P. Perturbations of Native Membrane Protein Structure in Alkyl Phosphocholine Detergents: A Critical Assessment of NMR and Biophysical Studies. Chem Rev 2018; 118:3559-3607. [PMID: 29488756 PMCID: PMC5896743 DOI: 10.1021/acs.chemrev.7b00570] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Indexed: 12/25/2022]
Abstract
Membrane proteins perform a host of vital cellular functions. Deciphering the molecular mechanisms whereby they fulfill these functions requires detailed biophysical and structural investigations. Detergents have proven pivotal to extract the protein from its native surroundings. Yet, they provide a milieu that departs significantly from that of the biological membrane, to the extent that the structure, the dynamics, and the interactions of membrane proteins in detergents may considerably vary, as compared to the native environment. Understanding the impact of detergents on membrane proteins is, therefore, crucial to assess the biological relevance of results obtained in detergents. Here, we review the strengths and weaknesses of alkyl phosphocholines (or foscholines), the most widely used detergent in solution-NMR studies of membrane proteins. While this class of detergents is often successful for membrane protein solubilization, a growing list of examples points to destabilizing and denaturing properties, in particular for α-helical membrane proteins. Our comprehensive analysis stresses the importance of stringent controls when working with this class of detergents and when analyzing the structure and dynamics of membrane proteins in alkyl phosphocholine detergents.
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Affiliation(s)
- Christophe Chipot
- SRSMC, UMR 7019 Université de Lorraine CNRS, Vandoeuvre-les-Nancy F-54500, France
- Laboratoire
International Associé CNRS and University of Illinois at Urbana−Champaign, Vandoeuvre-les-Nancy F-54506, France
- Department
of Physics, University of Illinois at Urbana−Champaign, 1110 West Green Street, Urbana, Illinois 61801, United States
| | - François Dehez
- SRSMC, UMR 7019 Université de Lorraine CNRS, Vandoeuvre-les-Nancy F-54500, France
- Laboratoire
International Associé CNRS and University of Illinois at Urbana−Champaign, Vandoeuvre-les-Nancy F-54506, France
| | - Jason R. Schnell
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Nicole Zitzmann
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | | | - Laurent J. Catoire
- Laboratory
of Biology and Physico-Chemistry of Membrane Proteins, Institut de Biologie Physico-Chimique (IBPC), UMR
7099 CNRS, Paris 75005, France
- University
Paris Diderot, Paris 75005, France
- PSL
Research University, Paris 75005, France
| | - Bruno Miroux
- Laboratory
of Biology and Physico-Chemistry of Membrane Proteins, Institut de Biologie Physico-Chimique (IBPC), UMR
7099 CNRS, Paris 75005, France
- University
Paris Diderot, Paris 75005, France
- PSL
Research University, Paris 75005, France
| | - Edmund R. S. Kunji
- Medical
Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Gianluigi Veglia
- Department
of Biochemistry, Molecular Biology, and Biophysics, and Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Timothy A. Cross
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
| | - Paul Schanda
- Université
Grenoble Alpes, CEA, CNRS, IBS, Grenoble F-38000, France
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10
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Rogawski R, Sergeyev IV, Zhang Y, Tran TH, Li Y, Tong L, McDermott AE. NMR Signal Quenching from Bound Biradical Affinity Reagents in DNP Samples. J Phys Chem B 2017; 121:10770-10781. [PMID: 29116793 PMCID: PMC5842680 DOI: 10.1021/acs.jpcb.7b08274] [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: 12/24/2022]
Abstract
We characterize the effect of specifically bound biradicals on the NMR spectra of dihydrofolate reductase from E. coli. Dynamic nuclear polarization methods enhance the signal-to-noise of solid state NMR experiments by transferring polarization from unpaired electrons of biradicals to nuclei. There has been recent interest in colocalizing the paramagnetic polarizing agents with the analyte of interest through covalent or noncovalent specific interactions. This experimental approach broadens the scope of dynamic nuclear polarization methods by offering the possibility of selective signal enhancements and the potential to work in a broad range of environments. Paramagnetic compounds can have other effects on the NMR spectroscopy of nearby nuclei, including broadening of nuclear resonances due to the proximity of the paramagnetic agent. Understanding the distance dependence of these interactions is important for the success of the technique. Here we explore paramagnetic signal quenching due to a bound biradical, specifically a biradical-derivatized trimethoprim ligand of E. coli dihydrofolate reductase. Biradical-derivatized trimethoprim has nanomolar affinity for its target, and affords strong and selective signal enhancements in dynamic nuclear polarization experiments. In this work, we show that, although the trimethoprim fragment is well ordered, the biradical (TOTAPOL) moiety is disordered when bound to the protein. The distance dependence in bleaching of NMR signal intensity allows us to detect numerous NMR signals in the protein. We present the possibility that static disorder and electron spin diffusion play roles in this observation, among other contributions. The fact that the majority of signals are observed strengthens the case for the use of high affinity or covalent radicals in dynamic nuclear polarization solid state NMR enhancement.
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Affiliation(s)
- Rivkah Rogawski
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Ivan V Sergeyev
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Yinglu Zhang
- Department of Biological Sciences, Columbia University , New York, New York 10027, United States
| | - Timothy H Tran
- Department of Biological Sciences, Columbia University , New York, New York 10027, United States
| | - Yongjun Li
- Department of Chemistry, Columbia University , New York, New York 10027, United States
| | - Liang Tong
- Department of Biological Sciences, Columbia University , New York, New York 10027, United States
| | - Ann E McDermott
- Department of Chemistry, Columbia University , New York, New York 10027, United States
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11
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Applications of NMR to membrane proteins. Arch Biochem Biophys 2017; 628:92-101. [PMID: 28529197 DOI: 10.1016/j.abb.2017.05.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 05/15/2017] [Accepted: 05/17/2017] [Indexed: 01/14/2023]
Abstract
Membrane proteins present a challenge for structural biology. In this article, we review some of the recent developments that advance the application of NMR to membrane proteins, with emphasis on structural studies in detergent-free, lipid bilayer samples that resemble the native environment. NMR spectroscopy is not only ideally suited for structure determination of membrane proteins in hydrated lipid bilayer membranes, but also highly complementary to the other principal techniques based on X-ray and electron diffraction. Recent advances in NMR instrumentation, spectroscopic methods, computational methods, and sample preparations are driving exciting new efforts in membrane protein structural biology.
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12
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Yao Y, Dutta SK, Park SH, Rai R, Fujimoto LM, Bobkov AA, Opella SJ, Marassi FM. High resolution solid-state NMR spectroscopy of the Yersinia pestis outer membrane protein Ail in lipid membranes. JOURNAL OF BIOMOLECULAR NMR 2017; 67:179-190. [PMID: 28239773 PMCID: PMC5490241 DOI: 10.1007/s10858-017-0094-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/08/2017] [Indexed: 06/06/2023]
Abstract
The outer membrane protein Ail (Adhesion invasion locus) is one of the most abundant proteins on the cell surface of Yersinia pestis during human infection. Its functions are expressed through interactions with a variety of human host proteins, and are essential for microbial virulence. Structures of Ail have been determined by X-ray diffraction and solution NMR spectroscopy, but those samples contained detergents that interfere with functionality, thus, precluding analysis of the structural basis for Ail's biological activity. Here, we demonstrate that high-resolution solid-state NMR spectra can be obtained from samples of Ail in detergent-free phospholipid liposomes, prepared with a lipid to protein molar ratio of 100. The spectra, obtained with 13C or 1H detection, have very narrow line widths (0.40-0.60 ppm for 13C, 0.11-0.15 ppm for 1H, and 0.46-0.64 ppm for 15N) that are consistent with a high level of sample homogeneity. The spectra enable resonance assignments to be obtained for N, CO, CA and CB atomic sites from 75 out of 156 residues in the sequence of Ail, including 80% of the transmembrane region. The 1H-detected solid-state NMR 1H/15N correlation spectra obtained for Ail in liposomes compare very favorably with the solution NMR 1H/15N TROSY spectra obtained for Ail in nanodiscs prepared with a similar lipid to protein molar ratio. These results set the stage for studies of the molecular basis of the functional interactions of Ail with its protein partners from human host cells, as well as the development of drugs targeting Ail.
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Affiliation(s)
- Yong Yao
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Samit Kumar Dutta
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Sang Ho Park
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0307, USA
| | - Ratan Rai
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0307, USA
| | - L Miya Fujimoto
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Andrey A Bobkov
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Stanley J Opella
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0307, USA
| | - Francesca M Marassi
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA.
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13
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Affiliation(s)
- Benjamin J. Wylie
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Hoa Q. Do
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Collin G. Borcik
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Emily P. Hardy
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
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14
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Zhang Z, Chen Y, Yang J. Band-selective heteronuclear dipolar recoupling with dual back-to-back pulses in rotating solids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 272:46-52. [PMID: 27623242 DOI: 10.1016/j.jmr.2016.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/31/2016] [Accepted: 09/05/2016] [Indexed: 06/06/2023]
Abstract
We propose a robust band-selective heteronuclear 15N-13C recoupling method using dual back-to-back (BABA) pulses (DBP). It contains four 90° pulses in each rotor period and corresponding phase cycling on each channel (13C and 15N). DBP aims at rapid band-selective heteronuclear magnetization transfer between 15N and 13Cα/13C', whose efficiency is close to that of the well-known SPECIFIC CP in membrane proteins with relatively short relaxation time in rotating frame (T1ρ). Compared to SPECIFIC CP, DBP is very simple to set up and highly robust to RF variations. Thus, it can reduce the efforts in experimental optimization, especially for low-sensitive samples, and is very suitable for long-time or quantitative experiments. The efficacy of DBP is demonstrated by the E. coli diacylglycerol kinase (DAGK) proteoliposome. We anticipate that DBP would be useful for (segments of) membrane proteins that undergo the μs-ms timescale motions in magic-angle spinning (MAS) solid-state NMR.
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Affiliation(s)
- Zhengfeng Zhang
- 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, Chinese Academy of Sciences, Wuhan 430071, PR 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, Chinese Academy of Sciences, Wuhan 430071, PR 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, Chinese Academy of Sciences, Wuhan 430071, PR China.
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15
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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: 48] [Impact Index Per Article: 5.3] [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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16
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Zhang Z, Fu R, Li J, Yang J. Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: relaxing selective polarization transfer condition between two dilute spins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 242:214-9. [PMID: 24691099 DOI: 10.1016/j.jmr.2014.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 03/03/2014] [Accepted: 03/04/2014] [Indexed: 05/21/2023]
Abstract
Double cross polarization (DCP) has been widely used for heteronuclear polarization transfer between (13)C and (15)N in solid-state magic-angle spinning (MAS) NMR. However, DCP is such sensitive to experimental settings that small variations or deviations in RF fields would deteriorate its efficiency. Here, we report on asymmetric simultaneous phase-inversion cross polarization (referred as aSPICP) for selective polarization transfer between low-γ (13)C and (15)N spins. We have demonstrated through simulations and experiments using biological solids that the asymmetric duration in the simultaneous phase-inversion cross polarization scheme leads to efficient polarization transfer between (13)C and (15)N even with large chemical shift anisotropies in the presence of B1 field variations or mismatch of the Hartmann-Hahn conditions. This could be very useful in the aspect of long-duration experiments for membrane protein studies at high fields.
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Affiliation(s)
- Zhengfeng Zhang
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China
| | - Riqiang Fu
- National High Magnetic Field Lab, Florida State University, Tallahassee, FL 32310, USA
| | - Jianping Li
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China
| | - Jun Yang
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China.
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17
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Miller AF. Solid-state NMR of flavins and flavoproteins. Methods Mol Biol 2014; 1146:307-40. [PMID: 24764096 DOI: 10.1007/978-1-4939-0452-5_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Why apply solid-state NMR (SSNMR) to flavins and flavoproteins? NMR provides information on an atom-specific basis about chemical functionality, structure, proximity to other groups, and dynamics of the system. Thus, it has become indispensable to the study of chemicals, materials, catalysts, and biomolecules. It is no surprise then that NMR has a great deal to offer in the study of flavins and flavoenzymes. In general, their catalytic or electron-transfer activity resides essentially in the flavin, a molecule eminently accessible by NMR. However, the specific reactivity displayed depends on a host of subtle interactions whereby the protein biases and reshapes the flavin's propensities to activate it for one reaction while suppressing other aspects of this cofactor's prodigious repertoire (Massey et al., J Biol Chem 244:3999-4006, 1969; Müller, Z Naturforsch 27B:1023-1026, 1972; Joosten and van Berkel, Curr Opin Struct Biol 11:195-202, 2007). Thus, we are fascinated to learn about how the flavin cofactor of one enzyme is, and is not, like the flavin cofactor of another. In what follows, we describe how the capabilities of SSNMR can help and are beginning to bear fruit in this exciting endeavor.
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Affiliation(s)
- Anne-Frances Miller
- Department of Chemistry, University of Kentucky, 505 Rose St, Lexington, KY, 40506-0055, USA,
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18
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Sinnige T, Weingarth M, Renault M, Baker L, Tommassen J, Baldus M. Solid-state NMR studies of full-length BamA in lipid bilayers suggest limited overall POTRA mobility. J Mol Biol 2014; 426:2009-21. [PMID: 24530687 DOI: 10.1016/j.jmb.2014.02.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/22/2014] [Accepted: 02/05/2014] [Indexed: 11/24/2022]
Abstract
The outer membrane protein BamA is the key player in β-barrel assembly in Gram-negative bacteria. Despite the availability of high-resolution crystal structures, the dynamic behavior of the transmembrane domain and the large periplasmic extension consisting of five POTRA (POlypeptide-TRansport-Associated) domains remains unclear. We demonstrate reconstitution of full-length BamA in proteoliposomes at low lipid-to-protein ratio, leading to high sensitivity and resolution in solid-state NMR (ssNMR) experiments. We detect POTRA domains in ssNMR experiments probing rigid protein segments in our preparations. These results suggest that the periplasmic region of BamA is firmly attached to the β-barrel and does not experience fast global motion around the angle between POTRA 2 and 3. We show that this behavior holds at lower protein concentrations and elevated temperatures. Chemical shift variations observed after reconstitution in lipids with different chain lengths and saturation levels are compatible with conformational plasticity of BamA's transmembrane domain. Electron microscopy of the ssNMR samples shows that BamA can cause local disruptions of the lipid bilayer in proteoliposomes. The observed interplay between protein-protein and protein-lipid interactions may be critical for BamA-mediated insertion of substrates into the outer membrane.
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Affiliation(s)
- Tessa Sinnige
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Markus Weingarth
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Marie Renault
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Lindsay Baker
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Jan Tommassen
- Department of Molecular Microbiology, Institute of Biomembranes, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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19
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Lalli D, Turano P. Solution and solid state NMR approaches to draw iron pathways in the ferritin nanocage. Acc Chem Res 2013; 46:2676-85. [PMID: 24000809 DOI: 10.1021/ar4000983] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Ferritins are intracellular proteins that can store thousands of iron(III) ions as a solid mineral. These structures autoassemble from four-helix bundle subunits to form a hollow sphere and are a prototypical example of protein nanocages. The protein acts as a reservoir, encapsulating iron as ferric oxide in its central cavity in a nontoxic and bioavailable form. Scientists have long known the structural details of the protein shell, owing to very high resolution X-ray structures of the apoform. However, the atomic level mechanism governing the multistep biomineralization process remained largely elusive. Through analysis of the chemical behavior of ferritin mutants, chemists have found the role of some residues in key reaction steps. Using Mössbauer and XAS, they have identified some di-iron intermediates of the catalytic reaction trapped by rapid freeze quench. However, structural information about the iron interaction sites remains scarce. The entire process is governed by a number of specific, but weak, interactions between the protein shell and the iron species moving across the cage. While this situation may constitute a major problem for crystallography, NMR spectroscopy represents an optimal tool to detect and characterize transient species involving soluble proteins. Regardless, NMR analysis of the 480 kDa ferritin represents a real challenge. Our interest in ferritin chemistry inspired us to use an original combination of solution and solid state approaches. While the highly symmetric structure of the homo-24-mer frog ferritin greatly simplifies the spectra, the large protein size hinders the efficient coherence transfer in solution, thus preventing the sequence specific assignments. In contrast, extensive (13)C-spin diffusion makes the solution (13)C-(13)C NOESY experiment our gold standard to monitor protein side chains both in the apoprotein alone and in its interaction with paramagnetic iron species, inducing line broadening on the resonances of nearby residues. We could retrieve the structural information embedded in the (13)C-(13)C NOESY due to a partial sequence specific assignment of protein backbone and side chains we obtained from solid state MAS NMR of ferritin microcrystals. We used the 59 assigned amino acids (∼33% of the total) as probes to locate paramagnetic ferric species in the protein cage. Through this approach, we could identify ferric dimers at the ferroxidase site and on their pathway towards the nanocage. Comparison with existing data on bacterioferritins and bacterial ferritins, as well as with eukaryotic ferritins loaded with various nonfunctional divalent ions, allowed us to reinterpret the available information. The resulting picture of the ferroxidase site is slightly different with various ferritins but is designed to provide multiple and generally weak iron ligands. The latter assist binding of two incoming iron(II) ions in two proximal positions to facilitate coupling with oxygen. Subsequent oxidation is accompanied by a decrease in the metal-metal distance (consistent with XAS/Mössbauer) and in the number of protein residues involved in metal coordination, facilitating the release of products as di-iron clusters under the effect of new incoming iron(II) ions.
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Affiliation(s)
- Daniela Lalli
- CERM and Department of Chemistry, University of Florence, via Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Paola Turano
- CERM and Department of Chemistry, University of Florence, via Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
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20
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Tang M, Comellas G, Rienstra CM. Advanced solid-state NMR approaches for structure determination of membrane proteins and amyloid fibrils. Acc Chem Res 2013; 46:2080-8. [PMID: 23659727 DOI: 10.1021/ar4000168] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Solid-state NMR (SSNMR) spectroscopy has become an important technique for studying the biophysics and structure biology of proteins. This technique is especially useful for insoluble membrane proteins and amyloid fibrils, which are essential for biological functions and are associated with human diseases. In the past few years, as major contributors to the rapidly advancing discipline of biological SSNMR, we have developed a family of methods for high-resolution structure determination of microcrystalline, fibrous, and membrane proteins. Key developments include order-of-magnitude improvements in sensitivity, resolution, instrument stability, and sample longevity under data collection conditions. These technical advances now enable us to apply new types of 3D and 4D experiments to collect atomic-resolution structural restraints in a site-resolved manner, such as vector angles, chemical shift tensors, and internuclear distances, throughout large proteins. In this Account, we present the technological advances in SSNMR approaches towards protein structure determination. We also describe the application of those methods for large membrane proteins and amyloid fibrils. Particularly, the SSNMR measurements of an integral membrane protein DsbB support the formation of a charge-transfer complex between DsbB and ubiquinone during the disulfide bond transfer pathways. The high-resolution structure of the DsbA-DsbB complex demonstrates that the joint calculation of X-ray and SSNMR restraints for membrane proteins with low-resolution crystal structure is generally applicable. The SSNMR investigations of α-synuclein fibrils from both wild type and familial mutants reveal that the structured regions of α-synuclein fibrils include the early-onset Parkinson's disease mutation sites. These results pave the way to understanding the mechanism of fibrillation in Parkinson's disease.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Gemma Comellas
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Chad M. Rienstra
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
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21
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Bhate MP, Wylie BJ, Thompson A, Tian L, Nimigean C, McDermott AE. Preparation of uniformly isotope labeled KcsA for solid state NMR: expression, purification, reconstitution into liposomes and functional assay. Protein Expr Purif 2013; 91:119-24. [PMID: 23916531 DOI: 10.1016/j.pep.2013.07.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 07/10/2013] [Accepted: 07/17/2013] [Indexed: 11/19/2022]
Abstract
We report the expression, purification, liposome reconstitution and functional validation of uniformly (13)C and (15)N isotope labeled KcsA, a bacterial potassium channel that has high homology with mammalian channels, for solid-state NMR studies. The expression and purification is optimized for an average yield of ∼35-40mg/L of M9 media in a time-efficient way. The protein purity is confirmed by gel electrophoresis and the protein concentration is quantified by UV-vis absorption spectroscopy. Protocols to efficiently reconstitute KcsA into liposomes are also presented. The presence of liposomes is confirmed by cryo-electron microscopy images and the effect of magic angle spinning on liposome packing is shown. High-resolution solid-state NMR spectra of uniformly isotope labeled KcsA in these liposomes reveal that our protocol yields to a very homogenous KcsA sample with high signal to noise and several well-resolved residues in NMR spectra. Electrophysiology of our samples before and after solid-state NMR show that channel function and selectivity remain intact after the solid-state NMR.
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Affiliation(s)
- Manasi P Bhate
- Department of Chemistry, Columbia University, NY 10027, United States.
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22
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Sperling LJ, Tang M, Berthold DA, Nesbitt AE, Gennis RB, Rienstra CM. Solid-state NMR study of a 41 kDa membrane protein complex DsbA/DsbB. J Phys Chem B 2013; 117:6052-60. [PMID: 23527473 DOI: 10.1021/jp400795d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The disulfide bond generation system in E. coli is led by a periplasmic protein, DsbA, and an integral membrane protein, DsbB. Here we present a solid-state NMR (SSNMR) study of a 41 kDa membrane protein complex DsbA/DsbB precipitated in the presence of native lipids to investigate conformational changes and dynamics that occur upon transient complex formation within the electron transfer pathway. Chemical shift changes in the periplasmic enzyme DsbA in three states (wild type, C33S mutant, and in complex with DsbB) reveal structural and/or dynamic information. We report a 4.9 ppm (15)N chemical shift change observed for Pro31 in the active site between the wild type and C33S mutant of DsbA. Additionally, the Pro31 residue remains elusive in the DsbA/DsbB complex, indicating that the dynamics change drastically in the active site between the three states of DsbA. Using three-dimensional SSNMR spectra, partial (13)C and (15)N de novo chemical shift assignments throughout DsbA in the DsbA/DsbB complex were compared with the shifts from DsbA alone to map site-specific chemical shift perturbations. These results demonstrate that there are further structural and dynamic changes of DsbA in the native membrane observed by SSNMR, beyond the differences between the crystal structures of DsbA and the DsbA/DsbB complex.
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Affiliation(s)
- Lindsay J Sperling
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
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23
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G-protein-coupled receptor structure, ligand binding and activation as studied by solid-state NMR spectroscopy. Biochem J 2013; 450:443-57. [DOI: 10.1042/bj20121644] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
GPCRs (G-protein-coupled receptors) are versatile signalling molecules at the cell surface and make up the largest and most diverse family of membrane receptors in the human genome. They convert a large variety of extracellular stimuli into intracellular responses through the activation of heterotrimeric G-proteins, which make them key regulatory elements in a broad range of normal and pathological processes, and are therefore one of the most important targets for pharmaceutical drug discovery. Knowledge of a GPCR structure enables us to gain a mechanistic insight into its function and dynamics, and further aid rational drug design. Despite intensive research carried out over the last three decades, resolving the structural basis of GPCR function is still a major activity. The crystal structures obtained in the last 5 years provide the first opportunity to understand how protein structure dictates the unique functional properties of these complex signalling molecules. However, owing to the intrinsic hydrophobicity, flexibility and instability of membrane proteins, it is still a challenge to crystallize GPCRs, and, when this is possible, it is no longer in its native membrane environment and no longer without modification. Furthermore, the conformational change of the transmembrane α-helices associated with the structure activation increases the difficulty of capturing the activation state of a GPCR to a higher resolution by X-ray crystallography. On the other hand, solid-state NMR may offer a unique opportunity to study membrane protein structure, ligand binding and activation at atomic resolution in the native membrane environment, as well as described functionally significant dynamics. In the present review, we discuss some recent achievements of solid-state NMR for understanding GPCRs, the largest mammalian proteome at ~1% of the total expressed proteins. Structural information, details of determination, details of ligand conformations and the consequences of ligand binding to initiate activation can all be explored with solid-state NMR.
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24
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Zhou DH, Nieuwkoop AJ, Berthold DA, Comellas G, Sperling LJ, Tang M, Shah GJ, Brea EJ, Lemkau LR, Rienstra CM. Solid-state NMR analysis of membrane proteins and protein aggregates by proton detected spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2012; 54:291-305. [PMID: 22986689 PMCID: PMC3484199 DOI: 10.1007/s10858-012-9672-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Accepted: 09/05/2012] [Indexed: 05/04/2023]
Abstract
Solid-state NMR has emerged as an important tool for structural biology and chemistry, capable of solving atomic-resolution structures for proteins in membrane-bound and aggregated states. Proton detection methods have been recently realized under fast magic-angle spinning conditions, providing large sensitivity enhancements for efficient examination of uniformly labeled proteins. The first and often most challenging step of protein structure determination by NMR is the site-specific resonance assignment. Here we demonstrate resonance assignments based on high-sensitivity proton-detected three-dimensional experiments for samples of different physical states, including a fully-protonated small protein (GB1, 6 kDa), a deuterated microcrystalline protein (DsbA, 21 kDa), a membrane protein (DsbB, 20 kDa) prepared in a lipid environment, and the extended core of a fibrillar protein (α-synuclein, 14 kDa). In our implementation of these experiments, including CONH, CO(CA)NH, CANH, CA(CO)NH, CBCANH, and CBCA(CO)NH, dipolar-based polarization transfer methods have been chosen for optimal efficiency for relatively high protonation levels (full protonation or 100 % amide proton), fast magic-angle spinning conditions (40 kHz) and moderate proton decoupling power levels. Each H-N pair correlates exclusively to either intra- or inter-residue carbons, but not both, to maximize spectral resolution. Experiment time can be reduced by at least a factor of 10 by using proton detection in comparison to carbon detection. These high-sensitivity experiments are especially important for membrane proteins, which often have rather low expression yield. Proton-detection based experiments are expected to play an important role in accelerating protein structure elucidation by solid-state NMR with the improved sensitivity and resolution.
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Affiliation(s)
- Donghua H. Zhou
- Department of Physics, Oklahoma State University, Stillwater, OK 74074, USA,
| | - Andrew J. Nieuwkoop
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
- Leibniz-Institut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Deborah A. Berthold
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Gemma Comellas
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Lindsay J. Sperling
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ming Tang
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Gautam J. Shah
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Elliott J. Brea
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Luisel R. Lemkau
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Chad M. Rienstra
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
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25
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Gopinath T, Veglia G. 3D DUMAS: simultaneous acquisition of three-dimensional magic angle spinning solid-state NMR experiments of proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 220:79-84. [PMID: 22698806 PMCID: PMC3487463 DOI: 10.1016/j.jmr.2012.04.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 04/13/2012] [Indexed: 05/15/2023]
Abstract
Using the DUMAS (Dual acquisition Magic Angle Spinning) solid-state NMR approach, we created new pulse schemes that enable the simultaneous acquisition of three dimensional (3D) experiments on uniformly (13)C, (15)N labeled proteins. These new experiments exploit the simultaneous cross-polarization (SIM-CP) from (1)H to (13)C and (15)N to acquire two 3D experiments simultaneously. This is made possible by bidirectional polarization transfer between (13)C and (15)N and the long living (15)N z-polarization in solid state NMR. To demonstrate the power of this approach, four 3D pulse sequences (NCACX, CANCO, NCOCX, CON(CA)CX) are combined into two pulse sequences (3D DUMAS-NCACX-CANCO, 3D DUMAS-NCOCX-CON(CA)CX) that allow simultaneous acquisition of these experiments, reducing the experimental time by approximately half. Importantly, the 3D DUMAS-NCACX-CANCO experiment alone makes it possible to obtain the majority of the backbone sequential resonance assignments for microcrystalline U-(13)C,(15)N ubiquitin. The DUMAS approach is general and applicable to many 3D experiments, nearly doubling the performance of NMR spectrometers.
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Affiliation(s)
- T. Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455
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Banigan JR, Traaseth NJ. Utilizing afterglow magnetization from cross-polarization magic-angle-spinning solid-state NMR spectroscopy to obtain simultaneous heteronuclear multidimensional spectra. J Phys Chem B 2012; 116:7138-44. [PMID: 22582831 PMCID: PMC3418334 DOI: 10.1021/jp303269m] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The time required for data acquisition and subsequent spectral assignment are limiting factors for determining biomolecular structure and dynamics using solid-state NMR spectroscopy. While strong magnetic dipolar couplings give rise to relatively broad spectra lines, the couplings also mediate the coherent magnetization transfer via the Hartmann-Hahn cross-polarization (HH-CP) experiment. This mechanism is used in nearly all backbone assignment experiments for carrying out polarization transfer between (1)H, (15)N, and (13)C. In this Article, we describe a general spectroscopic approach to use the residual or "afterglow" magnetization from the (15)N to (13)C selective HH-CP experiment to collect a second multidimensional heteronuclear data set. This approach allowed for the collection of two commonly used sequential assignment experiments (2D NCA and NCO or 3D NCACX and NCOCX) at the same time. Our "afterglow" technique was demonstrated with uniformly [(13)C,(15)N] and [1,3-(13)C] glycerol-labeled ubiquitin using instrumentation available on all standard solid-state NMR spectrometers configured for magic-angle-spinning. This method is compatible with several other sensitivity enhancement experiments and can be used as an isotopic filtering tool to reduce the spectral complexity and decrease the time needed for assignment.
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Affiliation(s)
- James R. Banigan
- Department of Chemistry, New York University, New York, NY 10003
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Eddy MT, Ong TC, Clark L, Teijido O, van der Wel PCA, Garces R, Wagner G, Rostovtseva TK, Griffin RG. Lipid dynamics and protein-lipid interactions in 2D crystals formed with the β-barrel integral membrane protein VDAC1. J Am Chem Soc 2012; 134:6375-87. [PMID: 22435461 PMCID: PMC3333839 DOI: 10.1021/ja300347v] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We employ a combination of (13)C/(15)N magic angle spinning (MAS) NMR and (2)H NMR to study the structural and functional consequences of different membrane environments on VDAC1 and, conversely, the effect of VDAC1 on the structure of the lipid bilayer. MAS spectra reveal a well-structured VDAC1 in 2D crystals of dimyristoylphosphatidylcholine (DMPC) and diphytanoylphosphatidylcholine (DPhPC), and their temperature dependence suggests that the VDAC structure does not change conformation above and below the lipid phase transition temperature. The same data show that the N-terminus remains structured at both low and high temperatures. Importantly, functional studies based on electrophysiological measurements on these same samples show fully functional channels, even without the presence of Triton X-100 that has been found necessary for in vitro-refolded channels. (2)H solid-state NMR and differential scanning calorimetry were used to investigate the dynamics and phase behavior of the lipids within the VDAC1 2D crystals. (2)H NMR spectra indicate that the presence of protein in DMPC results in a broad lipid phase transition that is shifted from 19 to ~27 °C and show the existence of different lipid populations, consistent with the presence of both annular and bulk lipids in the functionally and structurally homogeneous samples.
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Affiliation(s)
- Matthew T. Eddy
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ta-Chung Ong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Lindsay Clark
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Oscar Teijido
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Patrick C. A. van der Wel
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert Garces
- Department of Biological and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Gerhard Wagner
- Department of Biological and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Tatiana K. Rostovtseva
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert G. Griffin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Zhang Z, Miao Y, Liu X, Yang J, Li C, Deng F, Fu R. Dual-band selective double cross polarization for heteronuclear polarization transfer between dilute spins in solid-state MAS NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 217:92-9. [PMID: 22445831 PMCID: PMC3589810 DOI: 10.1016/j.jmr.2012.02.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 02/21/2012] [Accepted: 02/24/2012] [Indexed: 05/21/2023]
Abstract
A sinusoidal modulation scheme is described for selective heteronuclear polarization transfer between two dilute spins in double cross polarization magic-angle-spinning nuclear magnetic resonance spectroscopy. During the second N→C cross polarization, the (13)C RF amplitude is modulated sinusoidally while the (15)N RF amplitude is tangent. This modulation induces an effective spin-lock field in two selective frequency bands in either side of the (13)C RF carrier frequency, allowing for simultaneous polarization transfers from (15)N to (13)C in those two selective frequency bands. It is shown by experiments and simulations that this sinusoidal modulation allows one to selectively polarize from (15)N to its covalently bonded (13)Cα and (13)C' carbons in neighboring peptide planes simultaneously, which is useful for establishing the backbone connectivity between two sequential residues in protein structural elucidation. The selectivity and efficiency were experimentally demonstrated on a uniformly (13)C,(15)N-labeled β1 immunoglobulin binding domain of protein G (GB1).
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Affiliation(s)
- Zhengfeng Zhang
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China
| | - Yimin Miao
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
- National High Magnet Field Lab, Tallahassee, FL 32310, USA
| | - Xiaoli Liu
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China
| | - Jun Yang
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China
- Corresponding authors. Address: 1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA. Fax: +1 850 644 1366 (R. Fu). (J. Yang), (R. Fu)
| | - Conggang Li
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China
| | - Feng Deng
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China
| | - Riqiang Fu
- National High Magnet Field Lab, Tallahassee, FL 32310, USA
- Corresponding authors. Address: 1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA. Fax: +1 850 644 1366 (R. Fu). (J. Yang), (R. Fu)
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Reif B. Deuterated peptides and proteins: structure and dynamics studies by MAS solid-state NMR. Methods Mol Biol 2012; 831:279-301. [PMID: 22167680 DOI: 10.1007/978-1-61779-480-3_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Perdeuteration and back substitution of exchangeable protons in microcrystalline proteins, in combination with recrystallization from D(2)O-containing buffers, significantly reduce (1)H, (1)H dipolar interactions. This way, amide proton line widths on the order of 20 Hz are obtained. Aliphatic protons are accessible either via specifically protonated precursors or by using low amounts of H(2)O in the bacterial growth medium. The labeling scheme enables characterization of structure and dynamics in the solid-state without dipolar truncation artifacts.
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Affiliation(s)
- Bernd Reif
- Munich Center for Integrated Protein Science (CIPSM) at Department Chemie, Technische Universität München, Garching, Germany.
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30
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Brothers MC, Nesbitt AE, Hallock MJ, Rupasinghe SG, Tang M, Harris J, Baudry J, Schuler MA, Rienstra CM. VITAL NMR: using chemical shift derived secondary structure information for a limited set of amino acids to assess homology model accuracy. JOURNAL OF BIOMOLECULAR NMR 2012; 52:41-56. [PMID: 22183804 DOI: 10.1007/s10858-011-9576-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 09/28/2011] [Indexed: 05/31/2023]
Abstract
Homology modeling is a powerful tool for predicting protein structures, whose success depends on obtaining a reasonable alignment between a given structural template and the protein sequence being analyzed. In order to leverage greater predictive power for proteins with few structural templates, we have developed a method to rank homology models based upon their compliance to secondary structure derived from experimental solid-state NMR (SSNMR) data. Such data is obtainable in a rapid manner by simple SSNMR experiments (e.g., (13)C-(13)C 2D correlation spectra). To test our homology model scoring procedure for various amino acid labeling schemes, we generated a library of 7,474 homology models for 22 protein targets culled from the TALOS+/SPARTA+ training set of protein structures. Using subsets of amino acids that are plausibly assigned by SSNMR, we discovered that pairs of the residues Val, Ile, Thr, Ala and Leu (VITAL) emulate an ideal dataset where all residues are site specifically assigned. Scoring the models with a predicted VITAL site-specific dataset and calculating secondary structure with the Chemical Shift Index resulted in a Pearson correlation coefficient (-0.75) commensurate to the control (-0.77), where secondary structure was scored site specifically for all amino acids (ALL 20) using STRIDE. This method promises to accelerate structure procurement by SSNMR for proteins with unknown folds through guiding the selection of remotely homologous protein templates and assessing model quality.
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Affiliation(s)
- Michael C Brothers
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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31
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Franks WT, Linden AH, Kunert B, van Rossum BJ, Oschkinat H. Solid-state magic-angle spinning NMR of membrane proteins and protein-ligand interactions. Eur J Cell Biol 2011; 91:340-8. [PMID: 22019511 DOI: 10.1016/j.ejcb.2011.09.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 09/09/2011] [Accepted: 09/09/2011] [Indexed: 10/15/2022] Open
Abstract
Structural biology is developing into a universal tool for visualizing biological processes in space and time at atomic resolution. The field has been built by established methodology like X-ray crystallography, electron microscopy and solution NMR and is now incorporating new techniques, such as small-angle X-ray scattering, electron tomography, magic-angle-spinning solid-state NMR and femtosecond X-ray protein nanocrystallography. These new techniques all seek to investigate non-crystalline, native-like biological material. Solid-state NMR is a relatively young technique that has just proven its capabilities for de novo structure determination of model proteins. Further developments promise great potential for investigations on functional biological systems such as membrane-integrated receptors and channels, and macromolecular complexes attached to cytoskeletal proteins. Here, we review the development and applications of solid-state NMR from the first proof-of-principle investigations to mature structure determination projects, including membrane proteins. We describe the development of the methodology by looking at examples in detail and provide an outlook towards future 'big' projects.
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Affiliation(s)
- W Trent Franks
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert Rössle Str. 10, 13125 Berlin, Germany
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32
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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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33
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Affiliation(s)
- Simon G Patching
- Astbury Centre for Structural Molecular Biology and Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
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34
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Traaseth NJ, Veglia G. Frequency-selective heteronuclear dephasing and selective carbonyl labeling to deconvolute crowded spectra of membrane proteins by magic angle spinning NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 211:18-24. [PMID: 21482162 PMCID: PMC3328402 DOI: 10.1016/j.jmr.2011.03.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 03/10/2011] [Accepted: 03/14/2011] [Indexed: 05/15/2023]
Abstract
We present a new method that combines carbonyl-selective labeling with frequency-selective heteronuclear recoupling to resolve the spectral overlap of magic angle spinning (MAS) NMR spectra of membrane proteins in fluid lipid membranes with broad lines and high redundancy in the primary sequence. We implemented this approach in both heteronuclear (15)N-(13)C(α) and homonuclear (13)C-(13)C dipolar assisted rotational resonance (DARR) correlation experiments. We demonstrate its efficacy for the membrane protein phospholamban reconstituted in fluid PC/PE/PA lipid bilayers. The main advantage of this method is to discriminate overlapped (13)C(α) resonances by strategically labeling the preceding residue. This method is highly complementary to (13)C(i-1)(')-(15)N(i)-(13)C(i)(α) and (13)C(i-1)(α)-(15)N(i-1)-(13)C(i)(') experiments to distinguish inter-residue spin systems at a minimal cost to signal-to-noise.
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Affiliation(s)
- Nathaniel J. Traaseth
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55445
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55445
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55445
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35
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Tang M, Sperling LJ, Berthold DA, Nesbitt AE, Gennis RB, Rienstra CM. Solid-state NMR study of the charge-transfer complex between ubiquinone-8 and disulfide bond generating membrane protein DsbB. J Am Chem Soc 2011; 133:4359-66. [PMID: 21375236 DOI: 10.1021/ja107775w] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ubiquinone (Coenzyme Q) plays an important role in the mitochondrial respiratory chain and also acts as an antioxidant in its reduced form, protecting cellular membranes from peroxidation. De novo disulfide bond generation in the E. coli periplasm involves a transient complex consisting of DsbA, DsbB, and ubiquinone (UQ). It is hypothesized that a charge-transfer complex intermediate is formed between the UQ ring and the DsbB-C44 thiolate during the reoxidation of DsbA, which gives a distinctive ~500 nm absorbance band. No enzymological precedent exists for an UQ-protein thiolate charge-transfer complex, and definitive evidence of this unique reaction pathway for DsbB has not been fully demonstrated. In order to study the UQ-8-DsbB complex in the presence of native lipids, we have prepared isotopically labeled samples of precipitated DsbB (WT and C41S) with endogenous UQ-8 and lipids, and we have applied advanced multidimensional solid-state NMR methods. Double-quantum filter and dipolar dephasing experiments facilitated assignments of UQ isoprenoid chain resonances not previously observed and headgroup sites important for the characterization of the UQ redox states: methyls (~20 ppm), methoxys (~60 ppm), olefin carbons (120-140 ppm), and carbonyls (150-160 ppm). Upon increasing the DsbB(C41S) pH from 5.5 to 8.0, we observed a 10.8 ppm upfield shift for the UQ C1 and C4 carbonyls indicating an increase of electron density on the carbonyls. This observation is consistent with the deprotonation of the DsbB-C44 thiolate at pH 8.0 and provides direct evidence of the charge-transfer complex formation. A similar trend was noted for the UQ chemical shifts of the DsbA(C33S)-DsbB(WT) heterodimer, confirming that the charge-transfer complex is unperturbed by the DsbB(C41S) mutant used to mimic the intermediate state of the disulfide bond generating reaction pathway.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
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36
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Matsuki Y, Eddy MT, Griffin RG, Herzfeld J. Rapid three-dimensional MAS NMR spectroscopy at critical sensitivity. Angew Chem Int Ed Engl 2010; 49:9215-8. [PMID: 20957710 PMCID: PMC3495158 DOI: 10.1002/anie.201003329] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Yoh Matsuki
- Department of Chemistry, Brandeis University, Waltham MA 02454 (USA), Fax: (+1) 781 736 2538. Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge MA 02139 (USA)
| | - Matthew T. Eddy
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge MA 02139 (USA)
| | - Robert G. Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge MA 02139 (USA)
| | - Judith Herzfeld
- Department of Chemistry, Brandeis University, Waltham MA 02454 (USA), Fax: (+1) 781 736 2538
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Moseley HNB, Sperling LJ, Rienstra CM. Automated protein resonance assignments of magic angle spinning solid-state NMR spectra of β1 immunoglobulin binding domain of protein G (GB1). JOURNAL OF BIOMOLECULAR NMR 2010; 48:123-8. [PMID: 20931264 PMCID: PMC2962796 DOI: 10.1007/s10858-010-9448-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 08/18/2010] [Indexed: 05/11/2023]
Abstract
Magic-angle spinning solid-state NMR (MAS SSNMR) represents a fast developing experimental technique with great potential to provide structural and dynamics information for proteins not amenable to other methods. However, few automated analysis tools are currently available for MAS SSNMR. We present a methodology for automating protein resonance assignments of MAS SSNMR spectral data and its application to experimental peak lists of the β1 immunoglobulin binding domain of protein G (GB1) derived from a uniformly ¹³C- and ¹⁵N-labeled sample. This application to the 56 amino acid GB1 produced an overall 84.1% assignment of the N, CO, CA, and CB resonances with no errors using peak lists from NCACX 3D, CANcoCA 3D, and CANCOCX 4D experiments. This proof of concept demonstrates the tractability of this problem.
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39
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Matsuki Y, Eddy MT, Griffin RG, Herzfeld J. Rapid Three-Dimensional MAS NMR Spectroscopy at Critical Sensitivity. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201003329] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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40
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Renault M, Cukkemane A, Baldus M. Festkörper-NMR-Spektroskopie an komplexen Biomolekülen. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201002823] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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41
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Renault M, Cukkemane A, Baldus M. Solid-State NMR Spectroscopy on Complex Biomolecules. Angew Chem Int Ed Engl 2010; 49:8346-57. [DOI: 10.1002/anie.201002823] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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42
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Tycko R, Hu KN. A Monte Carlo/simulated annealing algorithm for sequential resonance assignment in solid state NMR of uniformly labeled proteins with magic-angle spinning. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 205:304-14. [PMID: 20547467 PMCID: PMC2902575 DOI: 10.1016/j.jmr.2010.05.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 05/19/2010] [Accepted: 05/21/2010] [Indexed: 05/05/2023]
Abstract
We describe a computational approach to sequential resonance assignment in solid state NMR studies of uniformly (15)N,(13)C-labeled proteins with magic-angle spinning. As input, the algorithm uses only the protein sequence and lists of (15)N/(13)C(alpha) crosspeaks from 2D NCACX and NCOCX spectra that include possible residue-type assignments of each crosspeak. Assignment of crosspeaks to specific residues is carried out by a Monte Carlo/simulated annealing algorithm, implemented in the program MC_ASSIGN1. The algorithm tolerates substantial ambiguity in residue-type assignments and coexistence of visible and invisible segments in the protein sequence. We use MC_ASSIGN1 and our own 2D spectra to replicate and extend the sequential assignments for uniformly-labeled HET-s(218-289) fibrils previously determined manually by Siemer et al. (J. Biomol. NMR, 34 (2006) 75-87) from a more extensive set of 2D and 3D spectra. Accurate assignments by MC_ASSIGN1 do not require data that are of exceptionally high quality. Use of MC_ASSIGN1 (and its extensions to other types of 2D and 3D data) is likely to alleviate many of the difficulties and uncertainties associated with manual resonance assignments in solid state NMR studies of uniformly labeled proteins, where spectral resolution and signal-to-noise are often sub-optimal.
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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, MD 20892-0520, USA.
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43
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Lange V, Becker-Baldus J, Kunert B, van Rossum BJ, Casagrande F, Engel A, Roske Y, Scheffel FM, Schneider E, Oschkinat H. A MAS NMR study of the bacterial ABC transporter ArtMP. Chembiochem 2010; 11:547-55. [PMID: 20099290 DOI: 10.1002/cbic.200900472] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
ATP-binding cassette (ABC) transport systems facilitate the translocation of substances, like amino acids, across cell membranes energised by ATP hydrolysis. This work describes first structural studies on the ABC transporter ArtMP from Geobacillus stearothermophilus in native lipid environment by magic-angle spinning NMR spectroscopy. The 2D crystals of ArtMP and 3D crystals of isolated ArtP were prepared in different nucleotide-bound or -unbound states. From selectively (13)C,(15)N-labelled ArtP, several sequence-specific assignments were obtained, most of which could be transferred to spectra of ArtMP. Residues Tyr133 and Pro134 protrude directly into the ATP-binding pocket at the interface of the ArtP subunits, and hence, are sensitive monitors for structural changes during nucleotide binding and hydrolysis. Distinct sets of NMR shifts were obtained for ArtP with different phosphorylation states of the ligand. Indications were found for an asymmetric or inhomogeneous state of the ArtP dimer bound with triphosphorylated nucleotides. With this investigation, a model system was established for screening all functional states occurring in one ABC transporter in native lipid environment.
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Affiliation(s)
- Vivien Lange
- NMR-Supported Structural Biology, Leibniz-Institut für Molekulare Pharmakologie, R.-Rössle-Strasse 10, 13125 Berlin, Germany
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Sperling LJ, Berthold DA, Sasser TL, Jeisy-Scott V, Rienstra CM. Assignment strategies for large proteins by magic-angle spinning NMR: the 21-kDa disulfide-bond-forming enzyme DsbA. J Mol Biol 2010; 399:268-82. [PMID: 20394752 PMCID: PMC2880403 DOI: 10.1016/j.jmb.2010.04.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 04/04/2010] [Indexed: 01/08/2023]
Abstract
We present strategies for chemical shift assignments of large proteins by magic-angle spinning solid-state NMR, using the 21-kDa disulfide-bond-forming enzyme DsbA as prototype. Previous studies have demonstrated that complete de novo assignments are possible for proteins up to approximately 17 kDa, and partial assignments have been performed for several larger proteins. Here we show that combinations of isotopic labeling strategies, high field correlation spectroscopy, and three-dimensional (3D) and four-dimensional (4D) backbone correlation experiments yield highly confident assignments for more than 90% of backbone resonances in DsbA. Samples were prepared as nanocrystalline precipitates by a dialysis procedure, resulting in heterogeneous linewidths below 0.2 ppm. Thus, high magnetic fields, selective decoupling pulse sequences, and sparse isotopic labeling all improved spectral resolution. Assignments by amino acid type were facilitated by particular combinations of pulse sequences and isotopic labeling; for example, transferred echo double resonance experiments enhanced sensitivity for Pro and Gly residues; [2-(13)C]glycerol labeling clarified Val, Ile, and Leu assignments; in-phase anti-phase correlation spectra enabled interpretation of otherwise crowded Glx/Asx side-chain regions; and 3D NCACX experiments on [2-(13)C]glycerol samples provided unique sets of aromatic (Phe, Tyr, and Trp) correlations. Together with high-sensitivity CANCOCA 4D experiments and CANCOCX 3D experiments, unambiguous backbone walks could be performed throughout the majority of the sequence. At 189 residues, DsbA represents the largest monomeric unit for which essentially complete solid-state NMR assignments have so far been achieved. These results will facilitate studies of nanocrystalline DsbA structure and dynamics and will enable analysis of its 41-kDa covalent complex with the membrane protein DsbB, for which we demonstrate a high-resolution two-dimensional (13)C-(13)C spectrum.
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Affiliation(s)
- Lindsay J. Sperling
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - Deborah A. Berthold
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - Terry L. Sasser
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - Victoria Jeisy-Scott
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - Chad M. Rienstra
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
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Abdine A, Verhoeven MA, Park KH, Ghazi A, Guittet E, Berrier C, Van Heijenoort C, Warschawski DE. Structural study of the membrane protein MscL using cell-free expression and solid-state NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 204:155-159. [PMID: 20194040 DOI: 10.1016/j.jmr.2010.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2009] [Revised: 02/01/2010] [Accepted: 02/08/2010] [Indexed: 05/28/2023]
Abstract
High-resolution structures of membrane proteins have so far been obtained mostly by X-ray crystallography, on samples where the protein is surrounded by detergent. Recent developments of solid-state NMR have opened the way to a new approach for the study of integral membrane proteins inside a membrane. At the same time, the extension of cell-free expression to the production of membrane proteins allows for the production of proteins tailor made for NMR. We present here an in situ solid-state NMR study of a membrane protein selectively labeled through the use of cell-free expression. The sample consists of MscL (mechano-sensitive channel of large conductance), a 75kDa pentameric alpha-helical ion channel from Escherichia coli, reconstituted in a hydrated lipid bilayer. Compared to a uniformly labeled protein sample, the spectral crowding is greatly reduced in the cell-free expressed protein sample. This approach may be a decisive step required for spectral assignment and structure determination of membrane proteins by solid-state NMR.
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Affiliation(s)
- Alaa Abdine
- UMR 7099, CNRS and Université Paris Diderot, IBPC, 13 rue Pierre et Marie Curie, F-75005 Paris, France
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Loquet A, Gardiennet C, Böckmann A. Protein 3D structure determination by high-resolution solid-state NMR. CR CHIM 2010. [DOI: 10.1016/j.crci.2010.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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NMR reveals pathway for ferric mineral precursors to the central cavity of ferritin. Proc Natl Acad Sci U S A 2009; 107:545-50. [PMID: 20018746 DOI: 10.1073/pnas.0908082106] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ferritin is a multimeric nanocage protein that directs the reversible biomineralization of iron. At the catalytic ferroxidase site two iron(II) ions react with dioxygen to form diferric species. In order to study the pathway of iron(III) from the ferroxidase site to the central cavity a new NMR strategy was developed to manage the investigation of a system composed of 24 monomers of 20 kDa each. The strategy is based on (13)C-(13)C solution NOESY experiments combined with solid-state proton-driven (13)C-(13)C spin diffusion and 3D coherence transfer experiments. In this way, 75% of amino acids were recognized and 35% sequence-specific assigned. Paramagnetic broadening, induced by iron(III) species in solution (13)C-(13)C NOESY spectra, localized the iron within each subunit and traced the progression to the central cavity. Eight iron ions fill the 20-A-long iron channel from the ferrous/dioxygen oxidoreductase site to the exit into the cavity, inside the four-helix bundle of each subunit, contrasting with short paths in models. Magnetic susceptibility data support the formation of ferric multimers in the iron channels. Multiple iron channel exits are near enough to facilitate high concentration of iron that can mineralize in the ferritin cavity, illustrating advantages of the multisubunit cage structure.
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Shi L, Lake EM, Ahmed MA, Brown LS, Ladizhansky V. Solid-state NMR study of proteorhodopsin in the lipid environment: Secondary structure and dynamics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2563-74. [DOI: 10.1016/j.bbamem.2009.09.011] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 09/16/2009] [Accepted: 09/21/2009] [Indexed: 11/26/2022]
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49
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Higman VA, Flinders J, Hiller M, Jehle S, Markovic S, Fiedler S, van Rossum BJ, Oschkinat H. Assigning large proteins in the solid state: a MAS NMR resonance assignment strategy using selectively and extensively 13C-labelled proteins. JOURNAL OF BIOMOLECULAR NMR 2009; 44:245-60. [PMID: 19609683 DOI: 10.1007/s10858-009-9338-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 06/22/2009] [Indexed: 05/04/2023]
Abstract
In recent years, solid-state magic-angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) has been growing into an important technique to study the structure of membrane proteins, amyloid fibrils and other protein preparations which do not form crystals or are insoluble. Currently, a key bottleneck is the assignment process due to the absence of the resolving power of proton chemical shifts. Particularly for large proteins (approximately >150 residues) it is difficult to obtain a full set of resonance assignments. In order to address this problem, we present an assignment method based upon samples prepared using [1,3-13C]- and [2-13C]-glycerol as the sole carbon source in the bacterial growth medium (so-called selectively and extensively labelled protein). Such samples give rise to higher quality spectra than uniformly [13C]-labelled protein samples, and have previously been used to obtain long-range restraints for use in structure calculations. Our method exploits the characteristic cross-peak patterns observed for the different amino acid types in 13C-13C correlation and 3D NCACX and NCOCX spectra. An in-depth analysis of the patterns and how they can be used to aid assignment is presented, using spectra of the chicken alpha-spectrin SH3 domain (62 residues), alphaB-crystallin (175 residues) and outer membrane protein G (OmpG, 281 residues) as examples. Using this procedure, over 90% of the Calpha, Cbeta, C' and N resonances in the core domain of alphaB-crystallin and around 73% in the flanking domains could be assigned (excluding 24 residues at the extreme termini of the protein).
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Affiliation(s)
- Victoria A Higman
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125 Berlin, Germany
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McDermott A. Structure and dynamics of membrane proteins by magic angle spinning solid-state NMR. Annu Rev Biophys 2009; 38:385-403. [PMID: 19245337 DOI: 10.1146/annurev.biophys.050708.133719] [Citation(s) in RCA: 288] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Membrane proteins remain difficult to study by traditional methods. Magic angle spinning solid-state NMR (MAS SSNMR) methods present an important approach for studying membrane proteins of moderate size. Emerging MAS SSNMR methods are based on extensive assignments of the nuclei as a basis for structure determination and characterization of function. These methods have already been used to characterize fibrils and globular proteins and are being increasingly used to study membrane proteins embedded in lipids. This review highlights recent applications to intrinsic membrane proteins and summarizes recent technical advances that will enable these methods to be utilized for more complex membrane protein systems in the near future.
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Affiliation(s)
- Ann McDermott
- Department of Chemistry, Columbia University, New York, NY 10027, USA.
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