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Hasanbasri Z, Tessmer MH, Stoll S, Saxena S. Modeling of Cu(II)-based protein spin labels using rotamer libraries. Phys Chem Chem Phys 2024; 26:6806-6816. [PMID: 38324256 PMCID: PMC10883468 DOI: 10.1039/d3cp05951k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
The bifunctional spin label double-histidine copper-(II) capped with nitrilotriacetate [dHis-Cu(II)-NTA], used in conjunction with electron paramagnetic resonance (EPR) methods can provide high-resolution distance data for investigating protein structure and backbone conformational diversity. Quantitative utilization of this data is limited due to a lack of rapid and accurate dHis-Cu(II)-NTA modeling methods that can be used to translate experimental data into modeling restraints. Here, we develop two dHis-Cu(II)-NTA rotamer libraries using a set of recently published molecular dynamics simulations and a semi-empirical meta-dynamics-based conformational ensemble sampling tool for use with the recently developed chiLife bifunctional spin label modeling method. The accuracy of both the libraries and the modeling method are tested by comparing model predictions to experimentally determined distance distributions. We show that this method is accurate with absolute deviation between the predicted and experimental modes between 0.0-1.2 Å with an average of 0.6 Å over the test data used. In doing so, we also validate the generality of the chiLife bifunctional label modeling method. Taken together, the increased structural resolution and modeling accuracy of dHis-Cu(II)-NTA over other spin labels promise improvements in the accuracy and resolution of protein models by EPR.
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Affiliation(s)
- Zikri Hasanbasri
- Department of Chemistry, University of Pittsburgh, PA, 15260, USA.
| | - Maxx H Tessmer
- Department of Chemistry, University of Washington, WA, 98195, USA.
| | - Stefan Stoll
- Department of Chemistry, University of Washington, WA, 98195, USA.
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, PA, 15260, USA.
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2
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Shamir Y, Goldbourt A. Atomic-Resolution Structure of the Protein Encoded by Gene V of fd Bacteriophage in Complex with Viral ssDNA Determined by Magic-Angle Spinning Solid-State NMR. J Am Chem Soc 2022; 145:300-310. [PMID: 36542094 PMCID: PMC9837838 DOI: 10.1021/jacs.2c09957] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
F-specific filamentous phages, elongated particles with circular single-stranded DNA encased in a symmetric protein capsid, undergo an intermediate step, where thousands of homodimers of a non-structural protein, gVp, bind to newly synthesized strands of DNA, preventing further DNA replication and preparing the circular genome in an elongated conformation for assembly of a new virion structure at the membrane. While the structure of the free homodimer is known, the ssDNA-bound conformation has yet to be determined. We report an atomic-resolution structure of the gVp monomer bound to ssDNA of fd phage in the nucleoprotein complex elucidated via magic-angle spinning solid-state NMR. The model presents significant conformational changes with respect to the free form. These modifications facilitate the binding mechanism and possibly promote cooperative binding in the assembly of the gVp-ssDNA complex.
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3
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Borcik CG, Eason IR, Yekefallah M, Amani R, Han R, Vanderloop BH, Wylie BJ. A Cholesterol Dimer Stabilizes the Inactivated State of an Inward-Rectifier Potassium Channel. Angew Chem Int Ed Engl 2022; 61:e202112232. [PMID: 34985791 PMCID: PMC8957755 DOI: 10.1002/anie.202112232] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Indexed: 12/15/2022]
Abstract
Cholesterol oligomers reside in multiple membrane protein X-ray crystal structures. Yet, there is no direct link between these oligomers and a biological function. Here we present the structural and functional details of a cholesterol dimer that stabilizes the inactivated state of an inward-rectifier potassium channel KirBac1.1. K+ efflux assays confirm that high cholesterol concentration reduces K+ conductance. We then determine the structure of the cholesterol-KirBac1.1 complex using Xplor-NIH simulated annealing calculations driven by solid-state NMR distance measurements. These calculations identified an α-α cholesterol dimer docked to a cleft formed by adjacent subunits of the homotetrameric protein. We compare these results to coarse grain molecular dynamics simulations. This is one of the first examples of a cholesterol oligomer performing a distinct biological function and structural characterization of a conserved promiscuous lipid binding region.
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Affiliation(s)
- Collin G Borcik
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Isaac R Eason
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Maryam Yekefallah
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Reza Amani
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Ruixian Han
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Boden H Vanderloop
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Benjamin J Wylie
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
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4
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Ahlawat S, Mote KR, Lakomek NA, Agarwal V. Solid-State NMR: Methods for Biological Solids. Chem Rev 2022; 122:9643-9737. [PMID: 35238547 DOI: 10.1021/acs.chemrev.1c00852] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In the last two decades, solid-state nuclear magnetic resonance (ssNMR) spectroscopy has transformed from a spectroscopic technique investigating small molecules and industrial polymers to a potent tool decrypting structure and underlying dynamics of complex biological systems, such as membrane proteins, fibrils, and assemblies, in near-physiological environments and temperatures. This transformation can be ascribed to improvements in hardware design, sample preparation, pulsed methods, isotope labeling strategies, resolution, and sensitivity. The fundamental engagement between nuclear spins and radio-frequency pulses in the presence of a strong static magnetic field is identical between solution and ssNMR, but the experimental procedures vastly differ because of the absence of molecular tumbling in solids. This review discusses routinely employed state-of-the-art static and MAS pulsed NMR methods relevant for biological samples with rotational correlation times exceeding 100's of nanoseconds. Recent developments in signal filtering approaches, proton methodologies, and multiple acquisition techniques to boost sensitivity and speed up data acquisition at fast MAS are also discussed. Several examples of protein structures (globular, membrane, fibrils, and assemblies) solved with ssNMR spectroscopy have been considered. We also discuss integrated approaches to structurally characterize challenging biological systems and some newly emanating subdisciplines in ssNMR spectroscopy.
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Affiliation(s)
- Sahil Ahlawat
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
| | - Kaustubh R Mote
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
| | - Nils-Alexander Lakomek
- University of Düsseldorf, Institute for Physical Biology, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Vipin Agarwal
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
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5
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Borcik CG, Eason IR, Yekefallah M, Amani R, Han R, Vanderloop BH, Wylie BJ. A Cholesterol Dimer Stabilizes the Inactivated State of an Inward‐Rectifier Potassium Channel. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Collin G. Borcik
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Isaac R. Eason
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Maryam Yekefallah
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Reza Amani
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Ruixian Han
- Department of Biochemistry University of Wisconsin-Madison Madison WI 53706 USA
| | - Boden H. Vanderloop
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Benjamin J. Wylie
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
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6
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van der Wel PCA. Dihedral Angle Measurements for Structure Determination by Biomolecular Solid-State NMR Spectroscopy. Front Mol Biosci 2021; 8:791090. [PMID: 34938776 PMCID: PMC8685456 DOI: 10.3389/fmolb.2021.791090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/22/2021] [Indexed: 11/13/2022] Open
Abstract
In structural studies of immobilized, aggregated and self-assembled biomolecules, solid-state NMR (ssNMR) spectroscopy can provide valuable high-resolution structural information. Among the structural restraints provided by magic angle spinning (MAS) ssNMR the canonical focus is on inter-atomic distance measurements. In the current review, we examine the utility of ssNMR measurements of angular constraints, as a complement to distance-based structure determination. The focus is on direct measurements of angular restraints via the judicious recoupling of multiple anisotropic ssNMR parameters, such as dipolar couplings and chemical shift anisotropies. Recent applications are highlighted, with a focus on studies of nanocrystalline polypeptides, aggregated peptides and proteins, receptor-substrate interactions, and small molecule interactions with amyloid protein fibrils. The review also examines considerations of when and where ssNMR torsion angle experiments are (most) effective, and discusses challenges and opportunities for future applications.
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Affiliation(s)
- Patrick C. A. van der Wel
- Solid-state NMR Group, Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
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7
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Nimerovsky E, Soutar CP. A modification of γ-encoded RN symmetry pulses for increasing the scaling factor and more accurate measurements of the strong heteronuclear dipolar couplings. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 319:106827. [PMID: 32950918 DOI: 10.1016/j.jmr.2020.106827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 06/11/2023]
Abstract
Symmetry based γ-encoded RNnν elements are broadly used in magic-angle spinning solid-state NMR experiments to achieve selective recoupling of the heteronuclear dipolar interactions. The recoupled dipolar couplings in such experiments are scaled by a factor, Ksc, which theoretically depends on the chosen symmetry numbers N, n, and ν. However, the maximum theoretical value of Ksc for γ-encoded RNnν pulses is limited to ~0.25, resulting in long RNnν experiment times. Also, the dependence of Ksc on the experimental parameters can result in systematic errors in the experimental determination of the dipolar couplings, especially at low and moderate MAS rates. In this manuscript, we investigate the use of MODifiEd RNnν symmetry (MODERNnν(ϕM)) pulses that increase the dipolar scaling factor by at least 1.45 fold compared to γ-encoded RNnν. The second advantage of MODERNnν(ϕM) pulses with respect to traditional RNnν pulses is the reduced influence of experimental parameters on Ksc, which allows for more accurate measurement of short-range distances. The robustness of MODERNnν(ϕM) is compared with γ-encoded R1423 symmetry pulses. The enhanced performance is demonstrated on two uniformly-13C-enriched samples, N-acetyl valine and the microcrystalline protein GB1, at a 31.111 kHz MAS rate.
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Affiliation(s)
- Evgeny Nimerovsky
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Corinne P Soutar
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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8
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Duong NT, Rossi F, Makrinich M, Goldbourt A, Chierotti MR, Gobetto R, Nishiyama Y. Accurate 1H- 14N distance measurements by phase-modulated RESPDOR at ultra-fast MAS. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 308:106559. [PMID: 31345769 DOI: 10.1016/j.jmr.2019.07.046] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
The combination of a phase-modulated (PM) saturation pulse and symmetry-based dipolar recoupling into a rotational-echo saturation-pulse double-resonance (RESPDOR) sequence has been employed to measure 1H-14N distances. Such a measurement is challenging owing to the quadrupolar interaction of 14N nucleus and the intense 1H-1H homonuclear dipolar interactions. Thanks to the recent advances in probe technology, the homonuclear dipolar interaction can be sufficiently suppressed at a fast MAS frequency (νR ≥ 60 kHz). PM pulse is robust to large variations of parameters on quadrupolar spins, but it has not been demonstrated under very fast MAS conditions. On the other hand, the RESPDOR sequence is applicable to such condition when it employs symmetry-based pulses during the recoupling period, but a prior knowledge on the system is required. In this article, we demonstrated the PM-RESPDOR combination for providing accurate 1H-14N distances at a very fast MAS frequency of 70 kHz on two samples, namely L-tyrosine⋅HCl and N-acetyl-L-alanine. This sequence, supported by simulations and experiments, has shown its feasibility at νR = 70 kHz as well as the robustness to the 14N quadrupolar interaction. It is applicable to a wide range of 1H-14N dipolar coupling constants when a radio frequency field on the 14N channel is approximately 80 kHz or more, while the PM pulse length lasts 10 rotor periods. For the first time, multiple 1H-14N heteronuclear dipolar couplings, thus multiple quantitative distances, are simultaneously and reliably extracted by fitting the experimental fraction curves with the analytical expression. The size of the 1H-14N dipolar interaction is solely used as a fitting parameter. These determined distances are in excellent agreement with those derived from diffraction techniques.
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Affiliation(s)
- Nghia Tuan Duong
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - Federica Rossi
- Department of Chemistry and NIS Centre, University of Torino, V.P. Giuria 7, 10125, Italy
| | - Maria Makrinich
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Amir Goldbourt
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Michele R Chierotti
- Department of Chemistry and NIS Centre, University of Torino, V.P. Giuria 7, 10125, Italy
| | - Roberto Gobetto
- Department of Chemistry and NIS Centre, University of Torino, V.P. Giuria 7, 10125, Italy
| | - Yusuke Nishiyama
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
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9
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Gallo A, Franks WT, Lewandowski JR. A suite of solid-state NMR experiments to utilize orphaned magnetization for assignment of proteins using parallel high and low gamma detection. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 305:219-231. [PMID: 31319283 DOI: 10.1016/j.jmr.2019.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/03/2019] [Accepted: 07/05/2019] [Indexed: 05/18/2023]
Abstract
We present a suite of two-receiver solid-state NMR experiments for backbone and side chain resonance assignment. The experiments rely on either dipolar coupling or scalar coupling for polarization transfer and are devised to acquire a 1H-detected 3D experiment AND a nested 13C-detected 2D from a shared excitation pulse. In order to compensate for the lower sensitivity of detection on 13C nucleus, 2D rows are signal averaged during 3D planes. The 3D dual receiver experiments do not suffer from any appreciable signal loss compared to their single receiver versions and require no extra optimization. The resulting data is higher in information content with no additional experiment time. The approach is expected to become widespread as multiple receivers become standard for new NMR spectrometers.
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Affiliation(s)
- A Gallo
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, UK
| | - W T Franks
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, UK; Department of Physics, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, UK
| | - J R Lewandowski
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, UK.
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10
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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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11
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Duong NT, Raran-Kurussi S, Nishiyama Y, Agarwal V. Quantitative 1H- 1H Distances in Protonated Solids by Frequency-Selective Recoupling at Fast Magic Angle Spinning NMR. J Phys Chem Lett 2018; 9:5948-5954. [PMID: 30247041 DOI: 10.1021/acs.jpclett.8b02189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy of protons in protonated solids is challenging. Fast magic angle spinning (MAS) and homonuclear decoupling schemes, in conjunction, with high magnetic fields have improved the proton resolution. However, experiments to quantitatively measure 1H-1H distances still remain elusive due to the dense proton-proton dipolar coupling network. A novel MAS solid-state NMR pulse sequence is proposed to selectively recouple and measure interproton distances in protonated samples. The phase-modulated sequence combined with a judicious choice of transmitter frequency is used to measure quantitative 1H-1H distances on the order of 3 Å in l-histidine·HCl·H2O, despite the presence of other strongly coupled protons. This method provides a major boost to NMR crystallography approaches for structural determination of pharmaceutical molecules by directly measuring 1H-1H distances. The band-selective nature of the sequence also enables observation of selective 1H-1H correlations (e.g., HN-HN/HN-Hα/ΗΝ-ΗMethyl) in peptides and proteins, which should serve as useful restraints in structure determination.
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Affiliation(s)
- Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center , RIKEN , Yokohama , Kanagawa 230-0045 , Japan
| | - Sreejith Raran-Kurussi
- TIFR Centre for Interdisciplinary Sciences , Tata Institute of Fundamental Research Hyderabad , Sy. No. 36/P , Gopanpally, Ranga Reddy District, Hyderabad 500 107 , India
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center , RIKEN , Yokohama , Kanagawa 230-0045 , Japan
- JEOL RESONANCE Inc. , Musashino, Akishima , Tokyo 196-8558 , Japan
| | - Vipin Agarwal
- TIFR Centre for Interdisciplinary Sciences , Tata Institute of Fundamental Research Hyderabad , Sy. No. 36/P , Gopanpally, Ranga Reddy District, Hyderabad 500 107 , India
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12
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Aharoni T, Goldbourt A. Rapid automated determination of chemical shift anisotropy values in the carbonyl and carboxyl groups of fd-y21m bacteriophage using solid state NMR. JOURNAL OF BIOMOLECULAR NMR 2018; 72:55-67. [PMID: 30141148 DOI: 10.1007/s10858-018-0206-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/17/2018] [Indexed: 06/08/2023]
Abstract
Determination of chemical shift anisotropy (CSA) in immobilized proteins and protein assemblies is one of several tools to determine protein dynamics on the timescales of microseconds and faster. The large CSA values of C=O groups in the rigid limit makes them in particular attractive for measurements of large amplitude motions, or their absence. In this study, we implement a 3D R-symmetry-based sequence that recouples the second spatial component of the 13C CSA with the corresponding isotropic 13C'-13C cross-peaks in order to probe backbone and sidechain dynamics in an intact fd-y21m filamentous phage viral capsid. The assignment of the isotropic cross-peaks and the analysis were conducted automatically using a new software named 'Raven'. The software can be utilized to auto-assign any 2D 13C-13C or 15N-13C spectrum given a previously-determined assignment table and generates simultaneously all intensity curves acquired in the third dimension. Here, all CSA spectra were automatically generated, and subsequently matched against a simulated set of CSA curves to yield their values. For the multi-copy, 50-residue-long protein capsid of fd-y21m, the backbone of the helical region is rigid, with reduced CSA values of ~ 12.5 kHz (~ 83 ppm). The N-terminus shows motionally-averaged CSA lineshapes and the carboxylic sidechain groups of four residues indicate large amplitude motions for D4, D5, D12 and E20. The current results further strengthen our previous studies of 15N CSA values and are in agreement with qualitative analysis of 13C-13C dipolar build-up curves, which were automatically obtained using our software. Our automated analysis technique is general and can be applied to study protein structure and dynamics, with data resulting from experiments that probe different variables such as relaxation rates and scaled anisotropic interactions.
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Affiliation(s)
- Tom Aharoni
- School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 6997801, Tel Aviv, Israel
| | - Amir Goldbourt
- School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 6997801, Tel Aviv, Israel.
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13
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Roos M, Wang T, Shcherbakov AA, Hong M. Fast Magic-Angle-Spinning 19F Spin Exchange NMR for Determining Nanometer 19F- 19F Distances in Proteins and Pharmaceutical Compounds. J Phys Chem B 2018; 122:2900-2911. [PMID: 29486126 PMCID: PMC6312665 DOI: 10.1021/acs.jpcb.8b00310] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Internuclear distances measured using NMR provide crucial constraints of three-dimensional structures but are often restricted to about 5 Å due to the weakness of nuclear-spin dipolar couplings. For studying macromolecular assemblies in biology and materials science, distance constraints beyond 1 nm will be extremely valuable. Here we present an extensive and quantitative analysis of the feasibility of 19F spin exchange NMR for precise and robust measurements of interatomic distances up to 1.6 nm at a magnetic field of 14.1 T, under 20-40 kHz magic-angle spinning (MAS). The measured distances are comparable to those achievable from paramagnetic relaxation enhancement but have higher precision, which is better than ±1 Å for short distances and ±2 Å for long distances. For 19F spins with the same isotropic chemical shift but different anisotropic chemical shifts, intermediate MAS frequencies of 15-25 kHz without 1H irradiation accelerate spin exchange. For spectrally resolved 19F-19F spin exchange, 1H-19F dipolar recoupling significantly speeds up 19F-19F spin exchange. On the basis of data from five fluorinated synthetic, pharmaceutical, and biological compounds, we obtained two general curves for spin exchange between CF groups and between CF3 and CF groups. These curves allow 19F-19F distances to be extracted from the measured spin exchange rates after taking into account 19F chemical shifts. These results demonstrate the robustness of 19F spin exchange NMR for distance measurements in a wide range of biological and chemical systems.
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Affiliation(s)
- Matthias Roos
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Tuo Wang
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Alexander A Shcherbakov
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Mei Hong
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
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Abstract
Various recent developments in solid-state nuclear magnetic resonance (ssNMR) spectroscopy have enabled an array of new insights regarding the structure, dynamics, and interactions of biomolecules. In the ever more integrated world of structural biology, ssNMR studies provide structural and dynamic information that is complementary to the data accessible by other means. ssNMR enables the study of samples lacking a crystalline lattice, featuring static as well as dynamic disorder, and does so independent of higher-order symmetry. The present study surveys recent applications of biomolecular ssNMR and examines how this technique is increasingly integrated with other structural biology techniques, such as (cryo) electron microscopy, solution-state NMR, and X-ray crystallography. Traditional ssNMR targets include lipid bilayer membranes and membrane proteins in a lipid bilayer environment. Another classic application has been in the area of protein misfolding and aggregation disorders, where ssNMR has provided essential structural data on oligomers and amyloid fibril aggregates. More recently, the application of ssNMR has expanded to a growing array of biological assemblies, ranging from non-amyloid protein aggregates, protein–protein complexes, viral capsids, and many others. Across these areas, multidimensional magic angle spinning (MAS) ssNMR has, in the last decade, revealed three-dimensional structures, including many that had been inaccessible by other structural biology techniques. Equally important insights in structural and molecular biology derive from the ability of MAS ssNMR to probe information beyond comprehensive protein structures, such as dynamics, solvent exposure, protein–protein interfaces, and substrate–enzyme interactions.
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15
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Della Ripa LA, Petros ZA, Cioffi AG, Piehl DW, Courtney JM, Burke MD, Rienstra CM. Solid-State NMR of highly 13C-enriched cholesterol in lipid bilayers. Methods 2018; 138-139:47-53. [PMID: 29366688 DOI: 10.1016/j.ymeth.2018.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/16/2018] [Accepted: 01/18/2018] [Indexed: 12/25/2022] Open
Abstract
Cholesterol (Chol) is vital for cell function as it is essential to a myriad of biochemical and biophysical processes. The atomistic details of Chol's interactions with phospholipids and proteins is therefore of fundamental interest, and NMR offers unique opportunities to interrogate these properties at high resolution. Towards this end, here we describe approaches for examining the structure and dynamics of Chol in lipid bilayers using high levels of 13C enrichment in combination with magic-angle spinning (MAS) methods. We quantify the incorporation levels and demonstrate high sensitivity and resolution in 2D 13C-13C and 1H-13C spectra, enabling de novo assignments and site-resolved order parameter measurements obtained in a fraction of the time required for experiments with natural abundance sterols. We envision many potential future applications of these methods to study sterol interactions with drugs, lipids and proteins.
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Affiliation(s)
- Lisa A Della Ripa
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Zoe A Petros
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Alexander G Cioffi
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Dennis W Piehl
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Joseph M Courtney
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Martin D Burke
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Carle-Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA.
| | - Chad M Rienstra
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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16
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Jagtap AP, Geiger MA, Stöppler D, Orwick-Rydmark M, Oschkinat H, Sigurdsson ST. bcTol : a highly water-soluble biradical for efficient dynamic nuclear polarization of biomolecules. Chem Commun (Camb) 2018; 52:7020-3. [PMID: 27161650 DOI: 10.1039/c6cc01813k] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dynamic nuclear polarization (DNP) is an efficient method to overcome the inherent low sensitivity of magic-angle spinning (MAS) solid-state NMR. We report a new polarizing agent (), designed for biological applications, that yielded an enhancement value of 244 in a microcrystalline SH3 domain sample at 110 K.
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Affiliation(s)
- Anil P Jagtap
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland.
| | - Michel-Andreas Geiger
- NMR supported structural biology, Leibniz-Institut for Molecular Biology (FMP), Robert-Roessle-Str. 10, 13125 Berlin, Germany.
| | - Daniel Stöppler
- NMR supported structural biology, Leibniz-Institut for Molecular Biology (FMP), Robert-Roessle-Str. 10, 13125 Berlin, Germany.
| | - Marcella Orwick-Rydmark
- NMR supported structural biology, Leibniz-Institut for Molecular Biology (FMP), Robert-Roessle-Str. 10, 13125 Berlin, Germany.
| | - Hartmut Oschkinat
- NMR supported structural biology, Leibniz-Institut for Molecular Biology (FMP), Robert-Roessle-Str. 10, 13125 Berlin, Germany.
| | - Snorri Th Sigurdsson
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland.
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17
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Morag O, Sgourakis NG, Abramov G, Goldbourt A. Filamentous Bacteriophage Viruses: Preparation, Magic-Angle Spinning Solid-State NMR Experiments, and Structure Determination. Methods Mol Biol 2018; 1688:67-97. [PMID: 29151205 DOI: 10.1007/978-1-4939-7386-6_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Filamentous bacteriophages are elongated semi-flexible viruses that infect bacteria. They consist of a circular single-stranded DNA (ssDNA) wrapped by a capsid consisting of thousands of copies of a major coat protein subunit. Given the increasing number of discovered phages and the existence of only a handful of structures, the development of methods for phage structure determination is valuable for biophysics and structural virology. In recent years, we developed and applied techniques to elucidate the 3D atomic-resolution structures of intact bacteriophages using experimental magic-angle spinning (MAS) solid-state NMR data. The flexibility in sample preparation - precipitated homogeneous solids - and the fact that ssNMR presents no limitation on the size, weight or morphology of the system under study makes it an ideal approach to study phage systems in detail.In this contribution, we describe approaches to prepare isotopically carbon-13 and nitrogen-15 enriched intact phage samples in high yield and purity, and we present experimental MAS NMR methods to study the capsid secondary and tertiary structure, and the DNA-capsid interface. Protocols for the capsid structure determination using the Rosetta modeling software are provided. Specific examples are given from studies of the M13 and fd filamentous bacteriophage viruses.
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Affiliation(s)
- Omry Morag
- School of Chemistry, Tel Aviv University, PO Box 39040, Tel Aviv, 69978041, Israel
| | - Nikolaos G Sgourakis
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Gili Abramov
- Department of Chemistry, New York University, New York, NY, USA
| | - Amir Goldbourt
- School of Chemistry, Tel Aviv University, PO Box 39040, Tel Aviv, 69978041, Israel.
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18
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Schwieters CD, Bermejo GA, Clore GM. Xplor-NIH for molecular structure determination from NMR and other data sources. Protein Sci 2017; 27:26-40. [PMID: 28766807 DOI: 10.1002/pro.3248] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 07/28/2017] [Indexed: 11/10/2022]
Abstract
Xplor-NIH is a popular software package for biomolecular structure determination from nuclear magnetic resonance (NMR) and other data sources. Here, some of Xplor-NIH's most useful data-associated energy terms are reviewed, including newer alternative options for using residual dipolar coupling data in structure calculations. Further, we discuss new developments in the implementation of strict symmetry for the calculation of symmetric homo-oligomers, and in the representation of the system as an ensemble of structures to account for motional effects. Finally, the different available force fields are presented, among other Xplor-NIH capabilities.
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Affiliation(s)
- Charles D Schwieters
- Imaging Sciences Laboratory, Center for Information Technology, National Institutes of Health, Bethesda, Maryland, 20892-5624
| | - Guillermo A Bermejo
- Imaging Sciences Laboratory, Center for Information Technology, National Institutes of Health, Bethesda, Maryland, 20892-5624
| | - G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0520
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19
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Adiram-Filiba N, Schremer A, Ohaion E, Nadav-Tsubery M, Lublin-Tennenbaum T, Keinan-Adamsky K, Goobes G. Ubiquitin immobilized on mesoporous MCM41 silica surfaces - Analysis by solid-state NMR with biophysical and surface characterization. Biointerphases 2017; 12:02D414. [PMID: 28565916 PMCID: PMC5451314 DOI: 10.1116/1.4983273] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 12/16/2022] Open
Abstract
Deriving the conformation of adsorbed proteins is important in the assessment of their functional activity when immobilized. This has particularly important bearings on the design of contemporary and new encapsulated enzyme-based drugs, biosensors, and other bioanalytical devices. Solid-state nuclear magnetic resonance (NMR) measurements can expand our molecular view of proteins in this state and of the molecular interactions governing protein immobilization on popular biocompatible surfaces such as silica. Here, the authors study the immobilization of ubiquitin on the mesoporous silica MCM41 by NMR and other techniques. Protein molecules are shown to bind efficiently at pH 5 through electrostatic interactions to individual MCM41 particles, causing their agglutination. The strong attraction of ubiquitin to MCM41 surface is given molecular context through evidence of proximity of basic, carbonyl and polar groups on the protein to groups on the silica surface using NMR measurements. The immobilized protein exhibits broad peaks in two-dimensional 13C dipolar-assisted rotational resonance spectra, an indication of structural multiplicity. At the same time, cross-peaks related to Tyr and Phe sidechains are missing due to motional averaging. Overall, the favorable adsorption of ubiquitin to MCM41 is accompanied by conformational heterogeneity and by a major loss of motional degrees of freedom as inferred from the marked entropy decrease. Nevertheless, local motions of the aromatic rings are retained in the immobilized state.
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Affiliation(s)
| | - Avital Schremer
- Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Eli Ohaion
- Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
| | | | | | | | - Gil Goobes
- Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel
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20
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Quinn CM, Polenova T. Structural biology of supramolecular assemblies by magic-angle spinning NMR spectroscopy. Q Rev Biophys 2017; 50:e1. [PMID: 28093096 PMCID: PMC5483179 DOI: 10.1017/s0033583516000159] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In recent years, exciting developments in instrument technology and experimental methodology have advanced the field of magic-angle spinning (MAS) nuclear magnetic resonance (NMR) to new heights. Contemporary MAS NMR yields atomic-level insights into structure and dynamics of an astounding range of biological systems, many of which cannot be studied by other methods. With the advent of fast MAS, proton detection, and novel pulse sequences, large supramolecular assemblies, such as cytoskeletal proteins and intact viruses, are now accessible for detailed analysis. In this review, we will discuss the current MAS NMR methodologies that enable characterization of complex biomolecular systems and will present examples of applications to several classes of assemblies comprising bacterial and mammalian cytoskeleton as well as human immunodeficiency virus 1 and bacteriophage viruses. The body of work reviewed herein is representative of the recent advancements in the field, with respect to the complexity of the systems studied, the quality of the data, and the significance to the biology.
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Affiliation(s)
- Caitlin M. Quinn
- University of Delaware, Department of Chemistry and Biochemistry, Newark, DE 19711; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, PA 15306
| | - Tatyana Polenova
- University of Delaware, Department of Chemistry and Biochemistry, Newark, DE 19711; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, PA 15306
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21
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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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22
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Tuttle MD, Comellas G, Nieuwkoop AJ, Covell DJ, Berthold DA, Kloepper KD, Courtney JM, Kim JK, Barclay AM, Kendall A, Wan W, Stubbs G, Schwieters CD, Lee VMY, George JM, Rienstra CM. Solid-state NMR structure of a pathogenic fibril of full-length human α-synuclein. Nat Struct Mol Biol 2016; 23:409-15. [PMID: 27018801 PMCID: PMC5034296 DOI: 10.1038/nsmb.3194] [Citation(s) in RCA: 693] [Impact Index Per Article: 86.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 02/25/2016] [Indexed: 12/17/2022]
Abstract
Misfolded α-synuclein amyloid fibrils are the principal components of Lewy bodies and neurites, hallmarks of Parkinson's disease (PD). We present a high-resolution structure of an α-synuclein fibril, in a form that induces robust pathology in primary neuronal culture, determined by solid-state NMR spectroscopy and validated by EM and X-ray fiber diffraction. Over 200 unique long-range distance restraints define a consensus structure with common amyloid features including parallel, in-register β-sheets and hydrophobic-core residues, and with substantial complexity arising from diverse structural features including an intermolecular salt bridge, a glutamine ladder, close backbone interactions involving small residues, and several steric zippers stabilizing a new orthogonal Greek-key topology. These characteristics contribute to the robust propagation of this fibril form, as supported by the structural similarity of early-onset-PD mutants. The structure provides a framework for understanding the interactions of α-synuclein with other proteins and small molecules, to aid in PD diagnosis and treatment.
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Affiliation(s)
- Marcus D Tuttle
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Gemma Comellas
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Andrew J Nieuwkoop
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Dustin J Covell
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Institute on Aging, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Deborah A Berthold
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Kathryn D Kloepper
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Joseph M Courtney
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jae K Kim
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Alexander M Barclay
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Amy Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - William Wan
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Gerald Stubbs
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Charles D Schwieters
- Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland, USA
| | - Virginia M Y Lee
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Institute on Aging, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Julia M George
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Chad M Rienstra
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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23
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Abstract
Our understanding of the molecular structures of amyloid fibrils that are associated with neurodegenerative diseases, of mechanisms by which disease-associated peptides and proteins aggregate into fibrils, and of structural properties of aggregation intermediates has advanced considerably in recent years. Detailed molecular structural models for certain fibrils and aggregation intermediates are now available. It is now well established that amyloid fibrils are generally polymorphic at the molecular level, with a given peptide or protein being capable of forming a variety of distinct, self-propagating fibril structures. Recent results from structural studies and from studies involving cell cultures, transgenic animals, and human tissue provide initial evidence that molecular structural variations in amyloid fibrils and related aggregates may correlate with or even produce variations in disease development. This article reviews our current knowledge of the structural and mechanistic aspects of amyloid formation, as well as current evidence for the biological relevance of structural variations.
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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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24
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Brown LS, Ladizhansky V. Membrane proteins in their native habitat as seen by solid-state NMR spectroscopy. Protein Sci 2015; 24:1333-46. [PMID: 25973959 DOI: 10.1002/pro.2700] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 04/07/2015] [Accepted: 04/09/2015] [Indexed: 12/21/2022]
Abstract
Membrane proteins play many critical roles in cells, mediating flow of material and information across cell membranes. They have evolved to perform these functions in the environment of a cell membrane, whose physicochemical properties are often different from those of common cell membrane mimetics used for structure determination. As a result, membrane proteins are difficult to study by traditional methods of structural biology, and they are significantly underrepresented in the protein structure databank. Solid-state Nuclear Magnetic Resonance (SSNMR) has long been considered as an attractive alternative because it allows for studies of membrane proteins in both native-like membranes composed of synthetic lipids and in cell membranes. Over the past decade, SSNMR has been rapidly developing into a major structural method, and a growing number of membrane protein structures obtained by this technique highlights its potential. Here we discuss membrane protein sample requirements, review recent progress in SSNMR methodologies, and describe recent advances in characterizing membrane proteins in the environment of a cellular membrane.
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Affiliation(s)
- Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Vladimir Ladizhansky
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
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25
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Huber M, Ovchinnikova OY, Schütz AK, Glockshuber R, Meier BH, Böckmann A. Solid-state NMR sequential assignment of Osaka-mutant amyloid-beta (Aβ1-40 E22Δ) fibrils. BIOMOLECULAR NMR ASSIGNMENTS 2015; 9:7-14. [PMID: 24395155 DOI: 10.1007/s12104-013-9535-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 12/12/2013] [Indexed: 06/03/2023]
Abstract
Alzheimer's disease (AD) is the most common form of dementia. Aggregation of amyloid β (Aβ), a peptide of 39-43 residues length, into insoluble fibrils is considered to initiate the disease. Determination of the molecular structure of Aβ fibrils is technically challenging and is a significant goal in AD research that may lead to design of effective therapeutical inhibitors of Aβ aggregation. Here, we present chemical-shift assignments for fibrils formed by highly pure recombinant Aβ1-40 with the Osaka E22Δ mutation that is found in familial AD. We show that that all regions of the peptide are rigid, including the N-terminal part often believed to be flexible in Aβ wt.
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Affiliation(s)
- Matthias Huber
- Laboratory of Physical Chemistry, ETH Zurich, Wolfgang Pauli Strasse 10, 8093, Zurich, Switzerland
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26
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β-Helical architecture of cytoskeletal bactofilin filaments revealed by solid-state NMR. Proc Natl Acad Sci U S A 2014; 112:E127-36. [PMID: 25550503 DOI: 10.1073/pnas.1418450112] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bactofilins are a widespread class of bacterial filament-forming proteins, which serve as cytoskeletal scaffolds in various cellular pathways. They are characterized by a conserved architecture, featuring a central conserved domain (DUF583) that is flanked by variable terminal regions. Here, we present a detailed investigation of bactofilin filaments from Caulobacter crescentus by high-resolution solid-state NMR spectroscopy. De novo sequential resonance assignments were obtained for residues Ala39 to Phe137, spanning the conserved DUF583 domain. Analysis of the secondary chemical shifts shows that this core region adopts predominantly β-sheet secondary structure. Mutational studies of conserved hydrophobic residues located in the identified β-strand segments suggest that bactofilin folding and polymerization is mediated by an extensive and redundant network of hydrophobic interactions, consistent with the high intrinsic stability of bactofilin polymers. Transmission electron microscopy revealed a propensity of bactofilin to form filament bundles as well as sheet-like, 2D crystalline assemblies, which may represent the supramolecular arrangement of bactofilin in the native context. Based on the diffraction pattern of these 2D crystalline assemblies, scanning transmission electron microscopy measurements of the mass per length of BacA filaments, and the distribution of β-strand segments identified by solid-state NMR, we propose that the DUF583 domain adopts a β-helical architecture, in which 18 β-strand segments are arranged in six consecutive windings of a β-helix.
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27
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Wang S, Ladizhansky V. Recent advances in magic angle spinning solid state NMR of membrane proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 82:1-26. [PMID: 25444696 DOI: 10.1016/j.pnmrs.2014.07.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 07/16/2014] [Accepted: 07/20/2014] [Indexed: 05/14/2023]
Abstract
Membrane proteins mediate many critical functions in cells. Determining their three-dimensional structures in the native lipid environment has been one of the main objectives in structural biology. There are two major NMR methodologies that allow this objective to be accomplished. Oriented sample NMR, which can be applied to membrane proteins that are uniformly aligned in the magnetic field, has been successful in determining the backbone structures of a handful of membrane proteins. Owing to methodological and technological developments, Magic Angle Spinning (MAS) solid-state NMR (ssNMR) spectroscopy has emerged as another major technique for the complete characterization of the structure and dynamics of membrane proteins. First developed on peptides and small microcrystalline proteins, MAS ssNMR has recently been successfully applied to large membrane proteins. In this review we describe recent progress in MAS ssNMR methodologies, which are now available for studies of membrane protein structure determination, and outline a few examples, which highlight the broad capability of ssNMR spectroscopy.
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Affiliation(s)
- Shenlin Wang
- Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing 100871, China; College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| | - Vladimir Ladizhansky
- Department of Physics, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada; Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada.
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28
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Lu JT, Lin JCY, Lin MC, Khupse ND, Lin IJB. Labile imidazolium salt protected palladium nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10440-10448. [PMID: 25098189 DOI: 10.1021/la501569e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
An imidazolium (Im) salt with two long alkyl substituents at N atoms is employed to prepare cubelike palladium nanoparticles (PdNPs). The bilayer nature of the capped Im salts is characterized by thermogravimetric analysis and NMR studies. These capped Im salts are labile, as evidenced by their displacement reaction with dimethylaminopyridine, and the observation of fast exchange between those free and capped Im salts on the NMR time scale. NMR results also show that these capped Im salts exhibit different diffusion rates, and interesting spinning rate dependent chemical shifts. These cubelike PdNPs could catalyze the Suzuki coupling of aryl chlorides and boronic acids with high yields in 10 min, even at room temperature.
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Affiliation(s)
- Jung-Tang Lu
- Department of Chemistry, National Dong-Hwa University , Shoufeng, Hualien 974, Taiwan
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29
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Linser R, Bardiaux B, Andreas L, Hyberts SG, Morris VK, Pintacuda G, Sunde M, Kwan AH, Wagner G. Solid-state NMR structure determination from diagonal-compensated, sparsely nonuniform-sampled 4D proton-proton restraints. J Am Chem Soc 2014; 136:11002-10. [PMID: 24988008 PMCID: PMC4132958 DOI: 10.1021/ja504603g] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Indexed: 01/21/2023]
Abstract
We report acquisition of diagonal-compensated protein structural restraints from four-dimensional solid-state NMR spectra on extensively deuterated and (1)H back-exchanged proteins. To achieve this, we use homonuclear (1)H-(1)H correlations with diagonal suppression and nonuniform sampling (NUS). Suppression of the diagonal allows the accurate identification of cross-peaks which are otherwise obscured by the strong autocorrelation or whose intensity is biased due to partial overlap with the diagonal. The approach results in unambiguous spectral interpretation and relatively few but reliable restraints for structure calculation. In addition, the diagonal suppression produces a spectrum with low dynamic range for which ultrasparse NUS data sets can be readily reconstructed, allowing straightforward application of NUS with only 2% sampling density with the advantage of more heavily sampling time-domain regions of high signal intensity. The method is demonstrated here for two proteins, α-spectrin SH3 microcrystals and hydrophobin functional amyloids. For the case of SH3, suppression of the diagonal results in facilitated identification of unambiguous restraints and improvement of the quality of the calculated structural ensemble compared to nondiagonal-suppressed 4D spectra. For the only partly assigned hydrophobin rodlets, the structure is yet unknown. Applied to this protein of biological significance with large inhomogeneous broadening, the method allows identification of unambiguous crosspeaks that are otherwise obscured by the diagonal.
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Affiliation(s)
- Rasmus Linser
- Max-Planck
Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
- Department
of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
- School
of Chemistry, University of New South Wales, Sydney NSW 2052, Australia
| | - Benjamin Bardiaux
- Unité
de Bioinformatique Structurale, CNRS UMR 3528, Institut Pasteur, Paris CEDEX 15, France
| | - Loren
B. Andreas
- Institut
des Sciences Analytiques, UMR 5280 CNRS/Ecole Normale Supérieure
de Lyon/Université de Lyon 1, 69100 Villeurbanne, France
| | - Sven G. Hyberts
- Department
of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Vanessa K. Morris
- School
of Medical Sciences and School of Molecular Bioscience, University of Sydney, Sydney NSW 2006, Australia
| | - Guido Pintacuda
- Institut
des Sciences Analytiques, UMR 5280 CNRS/Ecole Normale Supérieure
de Lyon/Université de Lyon 1, 69100 Villeurbanne, France
| | - Margaret Sunde
- School
of Medical Sciences and School of Molecular Bioscience, University of Sydney, Sydney NSW 2006, Australia
| | - Ann H. Kwan
- School
of Medical Sciences and School of Molecular Bioscience, University of Sydney, Sydney NSW 2006, Australia
| | - Gerhard Wagner
- Department
of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
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30
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Nomura K, Harada E, Sugase K, Shimamoto K. Solid-state NMR spectra of lipid-anchored proteins under magic angle spinning. J Phys Chem B 2014; 118:2405-13. [PMID: 24517164 DOI: 10.1021/jp4124106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Solid-state NMR is a promising tool for elucidating membrane-related biological phenomena. We achieved the measurement of high-resolution solid-state NMR spectra for a lipid-anchored protein embedded in lipid bilayers under magic angle spinning (MAS). To date, solid-state NMR measurements of lipid-anchored proteins have not been accomplished due to the difficulty in supplying sufficient amount of stable isotope labeled samples in the overexpression of lipid-anchored proteins requiring complex posttranslational modification. We designed a pseudo lipid-anchored protein in which the protein component was expressed in E. coli and attached to a chemically synthesized lipid-anchor mimic. Using two types of membranes, liposomes and bicelles, we demonstrated different types of insertion procedures for lipid-anchored protein into membranes. In the liposome sample, we were able to observe the cross-polarization and the (13)C-(13)C chemical shift correlation spectra under MAS, indicating that the liposome sample can be used to analyze molecular interactions using dipolar-based NMR experiments. In contrast, the bicelle sample showed sufficient quality of spectra through scalar-based experiments. The relaxation times and protein-membrane interaction were capable of being analyzed in the bicelle sample. These results demonstrated the applicability of two types of sample system to elucidate the roles of lipid-anchors in regulating diverse biological phenomena.
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Affiliation(s)
- Kaoru Nomura
- Bioorganic Research Institute, Suntory Foundation for Life Sciences , 1-1-1 Wakayamadai, Shimamoto-Cho, Mishima-Gun, Osaka 618-8503, Japan
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Watt ED, Rienstra CM. Recent advances in solid-state nuclear magnetic resonance techniques to quantify biomolecular dynamics. Anal Chem 2014; 86:58-64. [PMID: 24313950 PMCID: PMC3988533 DOI: 10.1021/ac403956k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Eric D Watt
- Department of Chemistry, ‡Department of Biochemistry, and §Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, Unites States
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Maltsev S, Lorigan GA. Membrane proteins structure and dynamics by nuclear magnetic resonance. Compr Physiol 2013; 1:2175-87. [PMID: 23733702 DOI: 10.1002/cphy.c110022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Membrane proteins represent a challenging class of biological systems to study. They are extremely difficult to crystallize and in most cases they retain their structure and functions only in membrane environments. Therefore, commonly used diffraction methods fail to give detailed molecular structure and other approaches have to be utilized to obtain biologically relevant information. Nuclear magnetic resonance (NMR) spectroscopy, however, can provide powerful structural and dynamical constraints on these complicated systems. Solution- and solid-state NMR are powerful methods for investigating membrane proteins studies. In this work, we briefly review both solution and solid-state NMR techniques for membrane protein studies and illustrate the applications of these methods to elucidate proteins structure, conformation, topology, dynamics, and function. Recent advances in electronics, biological sample preparation, and spectral processing provided opportunities for complex biological systems, such as membrane proteins inside lipid vesicles, to be studied faster and with outstanding quality. New analysis methods therefore have emerged, that benefit from the combination of sample preparation and corresponding specific high-end NMR techniques, which give access to more structural and dynamic information.
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Affiliation(s)
- Sergey Maltsev
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA
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Loquet A, Habenstein B, Chevelkov V, Vasa SK, Giller K, Becker S, Lange A. Atomic Structure and Handedness of the Building Block of a Biological Assembly. J Am Chem Soc 2013; 135:19135-8. [DOI: 10.1021/ja411362q] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Antoine Loquet
- Department
of NMR-based Structural
Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg
11, 37077 Göttingen, Germany
| | - Birgit Habenstein
- Department
of NMR-based Structural
Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg
11, 37077 Göttingen, Germany
| | - Veniamin Chevelkov
- Department
of NMR-based Structural
Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg
11, 37077 Göttingen, Germany
| | - Suresh Kumar Vasa
- Department
of NMR-based Structural
Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg
11, 37077 Göttingen, Germany
| | - Karin Giller
- Department
of NMR-based Structural
Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg
11, 37077 Göttingen, Germany
| | - Stefan Becker
- Department
of NMR-based Structural
Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg
11, 37077 Göttingen, Germany
| | - Adam Lange
- Department
of NMR-based Structural
Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg
11, 37077 Göttingen, Germany
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Yang Y, Fritzsching KJ, Hong M. Resonance assignment of the NMR spectra of disordered proteins using a multi-objective non-dominated sorting genetic algorithm. JOURNAL OF BIOMOLECULAR NMR 2013; 57:281-96. [PMID: 24132778 PMCID: PMC4004382 DOI: 10.1007/s10858-013-9788-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 10/03/2013] [Indexed: 05/05/2023]
Abstract
A multi-objective genetic algorithm is introduced to predict the assignment of protein solid-state NMR (SSNMR) spectra with partial resonance overlap and missing peaks due to broad linewidths, molecular motion, and low sensitivity. This non-dominated sorting genetic algorithm II (NSGA-II) aims to identify all possible assignments that are consistent with the spectra and to compare the relative merit of these assignments. Our approach is modeled after the recently introduced Monte-Carlo simulated-annealing (MC/SA) protocol, with the key difference that NSGA-II simultaneously optimizes multiple assignment objectives instead of searching for possible assignments based on a single composite score. The multiple objectives include maximizing the number of consistently assigned peaks between multiple spectra ("good connections"), maximizing the number of used peaks, minimizing the number of inconsistently assigned peaks between spectra ("bad connections"), and minimizing the number of assigned peaks that have no matching peaks in the other spectra ("edges"). Using six SSNMR protein chemical shift datasets with varying levels of imperfection that was introduced by peak deletion, random chemical shift changes, and manual peak picking of spectra with moderately broad linewidths, we show that the NSGA-II algorithm produces a large number of valid and good assignments rapidly. For high-quality chemical shift peak lists, NSGA-II and MC/SA perform similarly well. However, when the peak lists contain many missing peaks that are uncorrelated between different spectra and have chemical shift deviations between spectra, the modified NSGA-II produces a larger number of valid solutions than MC/SA, and is more effective at distinguishing good from mediocre assignments by avoiding the hazard of suboptimal weighting factors for the various objectives. These two advantages, namely diversity and better evaluation, lead to a higher probability of predicting the correct assignment for a larger number of residues. On the other hand, when there are multiple equally good assignments that are significantly different from each other, the modified NSGA-II is less efficient than MC/SA in finding all the solutions. This problem is solved by a combined NSGA-II/MC algorithm, which appears to have the advantages of both NSGA-II and MC/SA. This combination algorithm is robust for the three most difficult chemical shift datasets examined here and is expected to give the highest-quality de novo assignment of challenging protein NMR spectra.
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Affiliation(s)
- Yu Yang
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
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Loquet A, Habenstein B, Lange A. Structural investigations of molecular machines by solid-state NMR. Acc Chem Res 2013; 46:2070-9. [PMID: 23496894 DOI: 10.1021/ar300320p] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Essential biological processes such as cell motion, signaling,protein synthesis, and pathogen-host interactions rely on multifunctional molecular machines containing supramolecular assemblies, that is, noncovalently assembled protein subunits. Scientists would like to acquire a detailed atomic view of the complete molecular machine to understand its assembly process and functions. Structural biologists have used various approaches to obtain structural information such as X-ray crystallography, solution NMR, and electron microscopy. The inherent insolubility and large size of these multicomponent assemblies restrict the use of solution NMR, and their noncrystallinity and elongated shapes present obstacles to X-ray crystallography studies. Not limited by molecular weight or crystallinity, solid-state NMR (ssNMR) allows for structural investigations of supramolecular assemblies such as helical filaments, cross-β fibrils, or membrane-embedded oligomeric proteins. In this Account, we describe recent progress in the application of ssNMR to the elucidation of atomic structures of supramolecular assemblies. We highlight ssNMR methods to determine the subunit interfaces in symmetric arrangements. Our use of [1-(13)C]- or [2-(13)C]-glucose as a carbon source during bacterial protein expression results in significant (13)C spin dilution that drastically improves the spectral quality and enables us to detect meaningful structural restraints. Moreover, we can unequivocally determine intermolecular restraints using mixed [(1:1)1-(13)C/2-(13)C]-glucose labeled assemblies. We recently illustrated the power of this methodology with the structure determination of the type III secretion system (T3SS) needle. One crucial aspect in elucidating the atomic structure of these large multicomponent complexes is to determine the subunit-subunit interfaces. Notably, we could probe the needle subunit interfaces by collecting (13)C-(13)C intermolecular restraints. In contrast, these interfaces are not accessible via high-resolution cryo-EM. This approach is readily applicable to other supramolecular assemblies containing symmetrically repeating protein subunits, and could be combined with other techniques to get a more complete picture of multicomponent structures. To determine near-atomic structures of assemblies of biological interest, researchers could combine ssNMR data collected at the subunit interfaces with the envelope obtained from cryo-EM and potentially with monomeric subunit crystal structures.
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Affiliation(s)
- Antoine Loquet
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Birgit Habenstein
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Adam Lange
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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Bjerring M, Jain S, Paaske B, Vinther JM, Nielsen NC. Designing dipolar recoupling and decoupling experiments for biological solid-state NMR using interleaved continuous wave and RF pulse irradiation. Acc Chem Res 2013; 46:2098-107. [PMID: 23557787 DOI: 10.1021/ar300329g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Rapid developments in solid-state NMR methodology have boosted this technique into a highly versatile tool for structural biology. The invention of increasingly advanced rf pulse sequences that take advantage of better hardware and sample preparation have played an important part in these advances. In the development of these new pulse sequences, researchers have taken advantage of analytical tools, such as average Hamiltonian theory or lately numerical methods based on optimal control theory. In this Account, we focus on the interplay between these strategies in the systematic development of simple pulse sequences that combines continuous wave (CW) irradiation with short pulses to obtain improved rf pulse, recoupling, sampling, and decoupling performance. Our initial work on this problem focused on the challenges associated with the increasing use of fully or partly deuterated proteins to obtain high-resolution, liquid-state-like solid-state NMR spectra. Here we exploit the overwhelming presence of (2)H in such samples as a source of polarization and to gain structural information. The (2)H nuclei possess dominant quadrupolar couplings which complicate even the simplest operations, such as rf pulses and polarization transfer to surrounding nuclei. Using optimal control and easy analytical adaptations, we demonstrate that a series of rotor synchronized short pulses may form the basis for essentially ideal rf pulse performance. Using similar approaches, we design (2)H to (13)C polarization transfer experiments that increase the efficiency by one order of magnitude over standard cross polarization experiments. We demonstrate how we can translate advanced optimal control waveforms into simple interleaved CW and rf pulse methods that form a new cross polarization experiment. This experiment significantly improves (1)H-(15)N and (15)N-(13)C transfers, which are key elements in the vast majority of biological solid-state NMR experiments. In addition, we demonstrate how interleaved sampling of spectra exploiting polarization from (1)H and (2)H nuclei can substantially enhance the sensitivity of such experiments. Finally, we present systematic development of (1)H decoupling methods where CW irradiation of moderate amplitude is interleaved with strong rotor-synchronized refocusing pulses. We show that these sequences remove residual cross terms between dipolar coupling and chemical shielding anisotropy more effectively and improve the spectral resolution over that observed in current state-of-the-art methods.
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Affiliation(s)
- Morten Bjerring
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Denmark
| | - Sheetal Jain
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Denmark
| | - Berit Paaske
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Denmark
| | - Joachim M. Vinther
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Denmark
| | - Niels Chr. Nielsen
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Denmark
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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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Comellas G, Rienstra CM. Protein Structure Determination by Magic-Angle Spinning Solid-State NMR, and Insights into the Formation, Structure, and Stability of Amyloid Fibrils. Annu Rev Biophys 2013; 42:515-36. [DOI: 10.1146/annurev-biophys-083012-130356] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Chad M. Rienstra
- Center for Biophysics and Computational Biology,
- Department of Chemistry, and
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; ,
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Three-dimensional structure of CAP-gly domain of mammalian dynactin determined by magic angle spinning NMR spectroscopy: conformational plasticity and interactions with end-binding protein EB1. J Mol Biol 2013; 425:4249-66. [PMID: 23648839 DOI: 10.1016/j.jmb.2013.04.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/25/2013] [Accepted: 04/26/2013] [Indexed: 11/23/2022]
Abstract
Microtubules and their associated proteins play important roles in vesicle and organelle transport, cell motility and cell division. Perturbation of these processes by mutation typically gives rise to severe pathological conditions. In our efforts to obtain atomic information on microtubule-associated protein/microtubule interactions with the goal to understand mechanisms that might potentially assist in the development of treatments for these diseases, we have determined the three-dimensional structure of CAP-Gly (cytoskeleton-associated protein, glycine-rich) domain of mammalian dynactin by magic angle spinning NMR spectroscopy. We observe two conformations in the β2 strand encompassing residues T43-V44-A45, residues that are adjacent to the disease-associated mutation, G59S. Upon binding of CAP-Gly to microtubule plus-end tracking protein EB1, the CAP-Gly shifts to a single conformer. We find extensive chemical shift perturbations in several stretches of residues of CAP-Gly upon binding to EB1, from which we define accurately the CAP-Gly/EB1 binding interface. We also observe that the loop regions may exhibit unique flexibility, especially in the GKNDG motif, which participates in the microtubule binding. This study in conjunction with our previous reports suggests that conformational plasticity is an intrinsic property of CAP-Gly likely due to its unusually high loop content and may be required for its biological functions.
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Demers JP, Sgourakis NG, Gupta R, Loquet A, Giller K, Riedel D, Laube B, Kolbe M, Baker D, Becker S, Lange A. The common structural architecture of Shigella flexneri and Salmonella typhimurium type three secretion needles. PLoS Pathog 2013; 9:e1003245. [PMID: 23555258 PMCID: PMC3605151 DOI: 10.1371/journal.ppat.1003245] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 01/23/2013] [Indexed: 11/25/2022] Open
Abstract
The Type Three Secretion System (T3SS), or injectisome, is a macromolecular infection machinery present in many pathogenic Gram-negative bacteria. It consists of a basal body, anchored in both bacterial membranes, and a hollow needle through which effector proteins are delivered into the target host cell. Two different architectures of the T3SS needle have been previously proposed. First, an atomic model of the Salmonella typhimurium needle was generated from solid-state NMR data. The needle subunit protein, PrgI, comprises a rigid-extended N-terminal segment and a helix-loop-helix motif with the N-terminus located on the outside face of the needle. Second, a model of the Shigella flexneri needle was generated from a high-resolution 7.7-Å cryo-electron microscopy density map. The subunit protein, MxiH, contains an N-terminal α-helix, a loop, another α-helix, a 14-residue-long β-hairpin (Q51–Q64) and a C-terminal α-helix, with the N-terminus facing inward to the lumen of the needle. In the current study, we carried out solid-state NMR measurements of wild-type Shigella flexneri needles polymerized in vitro and identified the following secondary structure elements for MxiH: a rigid-extended N-terminal segment (S2-T11), an α-helix (L12-A38), a loop (E39-P44) and a C-terminal α-helix (Q45-R83). Using immunogold labeling in vitro and in vivo on functional needles, we located the N-terminus of MxiH subunits on the exterior of the assembly, consistent with evolutionary sequence conservation patterns and mutagenesis data. We generated a homology model of Shigella flexneri needles compatible with both experimental data: the MxiH solid-state NMR chemical shifts and the state-of-the-art cryoEM density map. These results corroborate the solid-state NMR structure previously solved for Salmonella typhimurium PrgI needles and establish that Shigella flexneri and Salmonella typhimurium subunit proteins adopt a conserved structure and orientation in their assembled state. Our study reveals a common structural architecture of T3SS needles, essential to understand T3SS-mediated infection and develop treatments. Gram-negative bacteria use a molecular machinery called the Type Three Secretion System (T3SS) to deliver toxic proteins to the host cell. Our research group has recently solved the structure of the extracellular T3SS needle of Salmonella typhimurium. Employing solid-state NMR, we could determine local structure parameters such as dihedral angles and inter-nuclear proximities for this supramolecular assembly. Concurrently, a high-resolution cryo-electron microscopy density map of the T3SS needle of Shigella flexneri was obtained by Fujii et al. Modeling of the Shigella needle subunit protein to fit the EM density produced a model incompatible with the atomic model of the Salmonella needle in terms of secondary structure and subunit orientation. Here, we determined directly the secondary structure of the Shigella needle subunit using solid-state NMR, and its orientation using in vitro and in vivo immunogold labeling in functional needles. We found that Shigella subunits adopt the same secondary structure and orientation as in the atomic model of Salmonella, and we generated a homology model of the Shigella needle consistent with the EM density. Knowing the common T3SS needle architecture is essential for understanding the secretion mechanism and interactions of the needle with other components of the T3SS, and to develop therapeutics.
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Affiliation(s)
- Jean-Philippe Demers
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Nikolaos G. Sgourakis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Rashmi Gupta
- Department for Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Antoine Loquet
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Karin Giller
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dietmar Riedel
- Laboratory for Electron Microscopy, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Britta Laube
- Core Facility Microscopy, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Michael Kolbe
- Department for Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
- * E-mail: (MK); (DB); (SB); (AL)
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail: (MK); (DB); (SB); (AL)
| | - Stefan Becker
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- * E-mail: (MK); (DB); (SB); (AL)
| | - Adam Lange
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- * E-mail: (MK); (DB); (SB); (AL)
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Asami S, Rakwalska-Bange M, Carlomagno T, Reif B. Untersuchung von Protein-RNA-Interaktionsstellen mithilfe 1H-detektierter MAS-Festkörper-NMR-Spektroskopie. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201208024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Qiang W, Tycko R. Zero-quantum stochastic dipolar recoupling in solid state nuclear magnetic resonance. J Chem Phys 2013; 137:104201. [PMID: 22979851 DOI: 10.1063/1.4749258] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the theoretical description and experimental demonstration of a zero-quantum stochastic dipolar recoupling (ZQ-SDR) technique for solid state nuclear magnetic resonance (NMR) studies of (13)C-labeled molecules, including proteins, under magic-angle spinning (MAS). The ZQ-SDR technique combines zero-quantum recoupling pulse sequence blocks with randomly varying chemical shift precession periods to create randomly amplitude- and phase-modulated effective homonuclear magnetic dipole-dipole couplings. To a good approximation, couplings between different (13)C spin pairs become uncorrelated under ZQ-SDR, leading to spin dynamics (averaged over many repetitions of the ZQ-SDR sequence) that are fully described by an orientation-dependent N × N polarization transfer rate matrix for an N-spin system, with rates that are inversely proportional to the sixth power of internuclear distances. Suppression of polarization transfers due to non-commutivity of pairwise couplings (i.e., dipolar truncation) does not occur under ZQ-SDR, as we show both analytically and numerically. Experimental demonstrations are reported for uniformly (13)C-labeled L-valine powder (at 14.1 T and 28.00 kHz MAS), uniformly (13)C-labeled protein GB1 in microcrystalline form (at 17.6 T and 40.00 kHz MAS), and partially labeled (13)C-labeled protein GB1 (at 14.1 T and 40.00 kHz MAS). The experimental results verify that spin dynamics under ZQ-SDR are described accurately by rate matrices and suggest the utility of ZQ-SDR in structural studies of (13)C-labeled solids.
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Affiliation(s)
- Wei Qiang
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
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Asami S, Rakwalska-Bange M, Carlomagno T, Reif B. Protein-RNA Interfaces Probed by1H-Detected MAS Solid-State NMR Spectroscopy. Angew Chem Int Ed Engl 2013; 52:2345-9. [DOI: 10.1002/anie.201208024] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Indexed: 11/08/2022]
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45
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Yao Y, Ding Y, Tian Y, Opella SJ, Marassi FM. Membrane protein structure determination: back to the membrane. Methods Mol Biol 2013; 1063:145-58. [PMID: 23975776 DOI: 10.1007/978-1-62703-583-5_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
NMR spectroscopy enables the structures of membrane proteins to be determined in the native-like environment of the phospholipid bilayer membrane. This chapter outlines the methods for membrane protein structural studies using solid-state NMR spectroscopy with samples of membrane proteins incorporated in proteoliposomes or planar lipid bilayers. The methods for protein expression and purification, sample preparation, and NMR experiments are described and illustrated with examples from OmpX and Ail, two bacterial outer membrane proteins that function in bacterial virulence.
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Affiliation(s)
- Yong Yao
- Sanford Burnham Medical Research Institute, La Jolla, CA, USA
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46
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Abstract
Nuclear magnetic resonance (NMR) spectroscopy is one of the most commonly used spectroscopic techniques to obtain information on the structure and dynamics of biological and chemical materials. A variety of samples can be studied including solutions, crystalline solids, powders and hydrated protein extracts. However, biological NMR spectroscopy is limited to concentrated samples, typically in the millimolar range, due to its intrinsic low sensitivity compared to other techniques such as fluorescence or electron paramagnetic resonance (EPR) spectroscopy.Dynamic nuclear polarization (DNP) is a method that increases the sensitivity of NMR by several orders of magnitude. It exploits a polarization transfer from unpaired electrons to neighboring nuclei which leads to an absolute increase of the signal-to-noise ratio (S/N). Consequently, biological samples with much lower concentrations can now be studied in hours or days compared to several weeks.This chapter will explain the different types of DNP enhanced NMR experiments, focusing primarily on solid-state magic angle spinning (MAS) DNP, its applications, and possible means of improvement.
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Schmidt-Rohr K, Fritzsching KJ, Liao SY, Hong M. Spectral editing of two-dimensional magic-angle-spinning solid-state NMR spectra for protein resonance assignment and structure determination. JOURNAL OF BIOMOLECULAR NMR 2012; 54:343-53. [PMID: 23053913 PMCID: PMC3656487 DOI: 10.1007/s10858-012-9676-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 09/14/2012] [Indexed: 05/05/2023]
Abstract
Several techniques for spectral editing of 2D (13)C-(13)C correlation NMR of proteins are introduced. They greatly reduce the spectral overlap for five common amino acid types, thus simplifying spectral assignment and conformational analysis. The carboxyl (COO) signals of glutamate and aspartate are selected by suppressing the overlapping amide N-CO peaks through (13)C-(15)N dipolar dephasing. The sidechain methine (CH) signals of valine, lecuine, and isoleucine are separated from the overlapping methylene (CH(2)) signals of long-chain amino acids using a multiple-quantum dipolar transfer technique. Both the COO and CH selection methods take advantage of improved dipolar dephasing by asymmetric rotational-echo double resonance (REDOR), where every other π-pulse is shifted from the center of a rotor period t(r) by about 0.15 t(r). This asymmetry produces a deeper minimum in the REDOR dephasing curve and enables complete suppression of the undesired signals of immobile segments. Residual signals of mobile sidechains are positively identified by dynamics editing using recoupled (13)C-(1)H dipolar dephasing. In all three experiments, the signals of carbons within a three-bond distance from the selected carbons are detected in the second spectral dimension via (13)C spin exchange. The efficiencies of these spectral editing techniques range from 60 % for the COO and dynamic selection experiments to 25 % for the CH selection experiment, and are demonstrated on well-characterized model proteins GB1 and ubiquitin.
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Affiliation(s)
- K. Schmidt-Rohr
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, IA 50011, USA
| | - K. J. Fritzsching
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, IA 50011, USA
| | - S. Y. Liao
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, IA 50011, USA
| | - Mei Hong
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, IA 50011, USA
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48
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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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49
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Asami S, Szekely K, Schanda P, Meier BH, Reif B. Optimal degree of protonation for ¹H detection of aliphatic sites in randomly deuterated proteins as a function of the MAS frequency. JOURNAL OF BIOMOLECULAR NMR 2012; 54:155-168. [PMID: 22915373 DOI: 10.1007/s10858-012-9659-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 08/08/2012] [Indexed: 06/01/2023]
Abstract
The (1)H dipolar network, which is the major obstacle for applying proton detection in the solid-state, can be reduced by deuteration, employing the RAP (Reduced Adjoining Protonation) labeling scheme, which yields random protonation at non-exchangeable sites. We present here a systematic study on the optimal degree of random sidechain protonation in RAP samples as a function of the MAS (magic angle spinning) frequency. In particular, we compare (1)H sensitivity and linewidth of a microcrystalline protein, the SH3 domain of chicken α-spectrin, for samples, prepared with 5-25 % H(2)O in the E. coli growth medium, in the MAS frequency range of 20-60 kHz. At an external field of 19.96 T (850 MHz), we find that using a proton concentration between 15 and 25 % in the M9 medium yields the best compromise in terms of sensitivity and resolution, with an achievable average (1)H linewidth on the order of 40-50 Hz. Comparing sensitivities at a MAS frequency of 60 versus 20 kHz, a gain in sensitivity by a factor of 4-4.5 is observed in INEPT-based (1)H detected 1D (1)H,(13)C correlation experiments. In total, we find that spectra recorded with a 1.3 mm rotor at 60 kHz have almost the same sensitivity as spectra recorded with a fully packed 3.2 mm rotor at 20 kHz, even though ~20× less material is employed. The improved sensitivity is attributed to (1)H line narrowing due to fast MAS and to the increased efficiency of the 1.3 mm coil.
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Affiliation(s)
- Sam Asami
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit und Umwelt (HMGU), Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
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50
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Abstract
For several different proteins an apparent correlation has been observed between the propensity for dimerization by domain-swapping and the ability to aggregate into amyloid-like fibrils. Examples include the disease-related proteins β 2-microglobulin and transthyretin. This has led to proposals that the amyloid-formation pathway may feature extensive domain swapping. One possible consequence of such an aggregation pathway is that the resulting fibrils would incorporate structural elements that resemble the domain-swapped forms of the protein and, thus, reflect certain native-like structures or domain-interactions. In magic angle spinning solid-state NMR-based and other structural studies of such amyloid fibrils, it appears that many of these proteins form fibrils that are not native-like. Several fibrils, instead, have an in-register, parallel conformation, which is a common amyloid structural motif and is seen, for instance, in various prion fibrils. Such a lack of native structure in the fibrils suggests that the apparent connection between domain-swapping ability and amyloid-formation may be more subtle or complex than may be presumed at first glance.
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Affiliation(s)
- Patrick C A van der Wel
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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