1
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Sergeyev IV, Fritzsching K, Rogawski R, McDermott A. Resolution in cryogenic solid state NMR: Challenges and solutions. Protein Sci 2024; 33:e4803. [PMID: 37847566 PMCID: PMC11184935 DOI: 10.1002/pro.4803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 09/30/2023] [Accepted: 10/03/2023] [Indexed: 10/18/2023]
Abstract
NMR at cryogenic temperatures has the potential to provide rich site-specific details regarding biopolymer structure, function, and mechanistic intermediates. Broad spectral lines compared with room temperature NMR can sometimes present practical challenges. A number of hypotheses regarding the origins of line broadening are explored. One frequently considered explanation is the presence of inhomogeneous conformational distributions. Possibly these arise when the facile characteristic motions that occur near room temperature become dramatically slower or "frozen out" at temperatures below the solvent phase change. Recent studies of low temperature spectra harness the distributions in properties in these low temperature spectra to uncover information regarding the conformational ensembles that drive biological function.
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Affiliation(s)
| | | | - Rivkah Rogawski
- Columbia University, Department of ChemistryNew YorkNew YorkUSA
| | - Ann McDermott
- Columbia University, Department of ChemistryNew YorkNew YorkUSA
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2
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Yi X, Zhang L, Friesner RA, McDermott A. Predicted and Experimental NMR Chemical Shifts at Variable Temperatures: The Effect of Protein Conformational Dynamics. J Phys Chem Lett 2024; 15:2270-2278. [PMID: 38381862 DOI: 10.1021/acs.jpclett.3c02589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
NMR chemical shifts provide a sensitive probe of protein structure and dynamics but remain challenging to predict and interpret. We examine the effect of protein conformational distributions on 15N chemical shifts for dihydrofolate reductase (DHFR), comparing QM/MM predicted shifts with experimental shifts in solution as well as frozen distributions. Representative snapshots from MD trajectories exhibit variation in predicted 15N chemical shifts of up to 25 ppm. The average over the fluctuations is in significantly better agreement with room temperature solution experimental values than the prediction for any single optimal conformations. Meanwhile, solid-state NMR (SSNMR) measurements of frozen solutions at 105 K exhibit broad lines whose widths agree well with the widths of distributions of predicted shifts for samples from the trajectory. The backbone torsion angle ψi-1 varies over 60° on the picosecond time scale, compensated by φi. These fluctuations can explain much of the shift variation.
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Affiliation(s)
- Xu Yi
- Department of Chemistry, Columbia University, New York, New York 10025, United States
| | - Lichirui Zhang
- Department of Chemistry, Columbia University, New York, New York 10025, United States
| | - Richard A Friesner
- Department of Chemistry, Columbia University, New York, New York 10025, United States
| | - Ann McDermott
- Department of Chemistry, Columbia University, New York, New York 10025, United States
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3
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Yi X, Fritzsching KJ, Rogawski R, Xu Y, McDermott AE. Contribution of protein conformational heterogeneity to NMR lineshapes at cryogenic temperatures. Proc Natl Acad Sci U S A 2024; 121:e2301053120. [PMID: 38346186 PMCID: PMC10895356 DOI: 10.1073/pnas.2301053120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 10/17/2023] [Indexed: 02/15/2024] Open
Abstract
While low-temperature Nuclear Magnetic Resonance (NMR) holds great promise for the analysis of unstable samples and for sensitizing NMR detection, spectral broadening in frozen protein samples is a common experimental challenge. One hypothesis explaining the additional linewidth is that a variety of conformations are in rapid equilibrium at room temperature and become frozen, creating an inhomogeneous distribution at cryogenic temperatures. Here, we investigate conformational heterogeneity by measuring the backbone torsion angle (Ψ) in Escherichia coli Dihydrofolate Reductase (DHFR) at 105 K. Motivated by the particularly broad N chemical shift distribution in this and other examples, we modified an established NCCN Ψ experiment to correlate the chemical shift of Ni+1 to Ψi. With selective 15N and 13C enrichment of Ile, only the unique I60-I61 pair was expected to be detected in 13C'-15N correlation spectrum. For this unique amide, we detected three different conformation basins based on dispersed chemical shifts. Backbone torsion angles Ψ were determined for each basin: 114 ± 7° for the major peak and 150 ± 8° and 164 ± 16° for the minor peaks as contrasted with 118° for the X-ray crystal structure (and 118° to 130° for various previously reported structures). These studies support the hypothesis that inhomogeneous distributions of protein backbone torsion angles contribute to the lineshape broadening in low-temperature NMR spectra.
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Affiliation(s)
- Xu Yi
- Department of Chemistry, Columbia University, New York, NY 1002
| | | | - Rivkah Rogawski
- Department of Chemistry, Columbia University, New York, NY 1002
| | - Yunyao Xu
- Department of Chemistry, Columbia University, New York, NY 1002
| | - Ann E McDermott
- Department of Chemistry, Columbia University, New York, NY 1002
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4
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Bhai L, Thomas JK, Conroy DW, Xu Y, Al-Hashimi HM, Jaroniec CP. Hydrogen bonding in duplex DNA probed by DNP enhanced solid-state NMR N-H bond length measurements. Front Mol Biosci 2023; 10:1286172. [PMID: 38111464 PMCID: PMC10726973 DOI: 10.3389/fmolb.2023.1286172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/09/2023] [Indexed: 12/20/2023] Open
Abstract
Numerous biological processes and mechanisms depend on details of base pairing and hydrogen bonding in DNA. Hydrogen bonds are challenging to quantify by X-ray crystallography and cryo-EM due to difficulty of visualizing hydrogen atom locations but can be probed with site specificity by NMR spectroscopy in solution and the solid state with the latter particularly suited to large, slowly tumbling DNA complexes. Recently, we showed that low-temperature dynamic nuclear polarization (DNP) enhanced solid-state NMR is a valuable tool for distinguishing Hoogsteen base pairs (bps) from canonical Watson-Crick bps in various DNA systems under native-like conditions. Here, using a model 12-mer DNA duplex containing two central adenine-thymine (A-T) bps in either Watson-Crick or Hoogsteen confirmation, we demonstrate DNP solid-state NMR measurements of thymine N3-H3 bond lengths, which are sensitive to details of N-H···N hydrogen bonding and permit hydrogen bonds for the two bp conformers to be systematically compared within the same DNA sequence context. For this DNA duplex, effectively identical TN3-H3 bond lengths of 1.055 ± 0.011 Å and 1.060 ± 0.011 Å were found for Watson-Crick A-T and Hoogsteen A (syn)-T base pairs, respectively, relative to a reference amide bond length of 1.015 ± 0.010 Å determined for N-acetyl-valine under comparable experimental conditions. Considering that prior quantum chemical calculations which account for zero-point motions predict a somewhat longer effective peptide N-H bond length of 1.041 Å, in agreement with solution and solid-state NMR studies of peptides and proteins at ambient temperature, to facilitate direct comparisons with these earlier studies TN3-H3 bond lengths for the DNA samples can be readily scaled appropriately to yield 1.083 Å and 1.087 Å for Watson-Crick A-T and Hoogsteen A (syn)-T bps, respectively, relative to the 1.041 Å reference peptide N-H bond length. Remarkably, in the context of the model DNA duplex, these results indicate that there are no significant differences in N-H···N A-T hydrogen bonds between Watson-Crick and Hoogsteen bp conformers. More generally, high precision measurements of N-H bond lengths by low-temperature DNP solid-state NMR based methods are expected to facilitate detailed comparative analysis of hydrogen bonding for a range of DNA complexes and base pairing environments.
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Affiliation(s)
- Lakshmi Bhai
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, United States
| | - Justin K. Thomas
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, United States
| | - Daniel W. Conroy
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, United States
| | - Yu Xu
- Department of Chemistry, Duke University, Durham, NC, United States
| | - Hashim M. Al-Hashimi
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, United States
| | - Christopher P. Jaroniec
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, United States
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5
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Kent JE, Ackermann BE, Debelouchina GT, Marassi FM. Dynamic Nuclear Polarization Illuminates Key Protein-Lipid Interactions in the Native Bacterial Cell Envelope. Biochemistry 2023; 62:2252-2256. [PMID: 37459255 PMCID: PMC11019665 DOI: 10.1021/acs.biochem.3c00262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Elucidating the structure and interactions of proteins in native environments is a fundamental goal of structural biology. Nuclear magnetic resonance (NMR) spectroscopy is well suited for this task but often suffers from low sensitivity, especially in complex biological settings. Here, we use a sensitivity-enhancement technique called dynamic nuclear polarization (DNP) to overcome this challenge. We apply DNP to capture the membrane interactions of the outer membrane protein Ail, a key component of the host invasion pathway of Yersinia pestis. We show that the DNP-enhanced NMR spectra of Ail in native bacterial cell envelopes are well resolved and enriched in correlations that are invisible in conventional solid-state NMR experiments. Furthermore, we demonstrate the ability of DNP to capture elusive interactions between the protein and the surrounding lipopolysaccharide layer. Our results support a model where the extracellular loop arginine residues remodel the membrane environment, a process that is crucial for host invasion and pathogenesis.
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Affiliation(s)
- James E Kent
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, United States
| | - Bryce E Ackermann
- Department Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Galia T Debelouchina
- Department Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Francesca M Marassi
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, United States
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226-3548, United States
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6
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Kent JE, Ackermann BE, Debelouchina GT, Marassi FM. Dynamic nuclear polarization illuminates key protein-lipid interactions in the native bacterial cell envelope. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.18.541325. [PMID: 37292594 PMCID: PMC10245764 DOI: 10.1101/2023.05.18.541325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Elucidating the structure and interactions of proteins in native environments has become a fundamental goal of structural biology. Nuclear magnetic resonance (NMR) spectroscopy is well suited for this task but often suffers from low sensitivity, especially in complex biological settings. Here, we use a sensitivity-enhancement technique called dynamic nuclear polarization (DNP) to overcome this challenge. We apply DNP to capture the membrane interactions of the outer membrane protein Ail, a key component of the host invasion pathway of Yersinia pestis . We show that the DNP-enhanced NMR spectra of Ail in native bacterial cell envelopes are well resolved and enriched in correlations that are invisible in conventional solid-state NMR experiments. Furthermore, we demonstrate the ability of DNP to capture elusive interactions between the protein and the surrounding lipopolysaccharide layer. Our results support a model where the extracellular loop arginine residues remodel the membrane environment, a process that is crucial for host invasion and pathogenesis.
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7
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Liu J, Wu XL, Zeng YT, Hu ZH, Lu JX. Solid-state NMR studies of amyloids. Structure 2023; 31:230-243. [PMID: 36750098 DOI: 10.1016/j.str.2023.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 10/10/2022] [Accepted: 01/09/2023] [Indexed: 02/08/2023]
Abstract
Amyloids have special structural properties and are involved in many aspects of biological function. In particular, amyloids are the cause or hallmarks of a group of notorious and incurable neurodegenerative diseases. The extraordinary high molecular weight and aggregation states of amyloids have posed a challenge for researchers studying them. Solid-state NMR (SSNMR) has been extensively applied to study the structures and dynamics of amyloids for the past 20 or more years and brought us tremendous progress in understanding their structure and related diseases. These studies, at the same time, helped to push SSNMR technical developments in sensitivity and resolution. In this review, some interesting research studies and important technical developments are highlighted to give the reader an overview of the current state of this field.
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Affiliation(s)
- Jing Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xia-Lian Wu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yu-Teng Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zhi-Heng Hu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jun-Xia Lu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
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8
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Yi X, Zhang L, Friesner RA, McDermott A. Predicted and Experimental NMR Chemical Shifts at Variable Temperatures: The Effect of Protein Conformational Dynamics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.25.525502. [PMID: 36747635 PMCID: PMC9900828 DOI: 10.1101/2023.01.25.525502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
NMR chemical shifts provide a sensitive probe of protein structure and dynamics. Prediction of shifts, and therefore interpretation of shifts, particularly for the frequently measured amidic 15 N sites, remains a tall challenge. We demonstrate that protein 15 N chemical shift prediction from QM/MM predictions can be improved if conformational variation is included via MD sampling, focusing on the antibiotic target, E. coli Dihydrofolate reductase (DHFR). Variations of up to 25 ppm in predicted 15 N chemical shifts are observed over the trajectory. For solution shifts the average of fluctuations on the low picosecond timescale results in a superior prediction to a single optimal conformation. For low temperature solid state measurements, the histogram of predicted shifts for locally minimized snapshots with specific solvent arrangements sampled from the trajectory explains the heterogeneous linewidths; in other words, the conformations and associated solvent are 'frozen out' at low temperatures and result in inhomogeneously broadened NMR peaks. We identified conformational degrees of freedom that contribute to chemical shift variation. Backbone torsion angles show high amplitude fluctuations during the trajectory on the low picosecond timescale. For a number of residues, including I60, ψ varies by up to 60º within a conformational basin during the MD simulations, despite the fact that I60 (and other sites studied) are in a secondary structure element and remain well folded during the trajectory. Fluctuations in ψ appear to be compensated by other degrees of freedom in the protein, including φ of the succeeding residue, resulting in "rocking" of the amide plane with changes in hydrogen bonding interactions. Good agreement for both room temperature and low temperature NMR spectra provides strong support for the specific approach to conformational averaging of computed chemical shifts.
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9
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Yi X, Fritzsching KJ, Rogawski R, Xu Y, McDermott AE. Contribution of protein conformational heterogeneity to NMR lineshapes at cryogenic temperatures. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.24.525358. [PMID: 36747795 PMCID: PMC9900807 DOI: 10.1101/2023.01.24.525358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
While low temperature NMR holds great promise for the analysis of unstable samples and for sensitizing NMR detection, spectral broadening in frozen protein samples is a common experimental challenge. One hypothesis explaining the additional linewidth is that a variety of conformations are in rapid equilibrium at room temperature and become frozen, creating an inhomogeneous distribution at cryogenic temperatures. Here we investigate conformational heterogeneity by measuring the backbone torsion angle (Ψ) in E. coli DHFR at 105K. Motivated by the particularly broad N chemical shift distribution in this and other examples, we modified an established NCCN Ψ experiment to correlate the chemical shift of N i+1 to Ψ i . With selective 15 N and 13 C enrichment of Ile, only the unique I60-I61 pair was expected to be detected in 13 C'- 15 N correlation spectrum. For this unique amide we detected three different conformation basins based on dispersed chemical shifts. Backbone torsion angles Ψ were determined for each basin 114 ± 7 for the major peak, and 150 ± 8 and 164 ± 16° for the minor peak as contrasted with 118 for the X-ray crystal structure (and 118-130 for various previously reported structures). These studies support the hypothesis that inhomogeneous distributions of protein backbone torsion angles contribute to the lineshape broadening in low temperature NMR spectra. Significance Statement Understanding protein conformational flexibility is essential for insights into the molecular basis of protein function and the thermodynamics of proteins. Here we investigate the ensemble of protein backbone conformations in a frozen protein freezing, which is likely a close representation for the ensemble in rapid equilibrium at room temperature. Various conformers are spectrally resolved due to the exquisite sensitivity of NMR shifts to local conformations, and NMR methods allow us to directly probe the torsion angles corresponding to each band of chemical shifts.
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10
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Elathram N, Ackermann BE, Debelouchina GT. DNP-enhanced solid-state NMR spectroscopy of chromatin polymers. JOURNAL OF MAGNETIC RESONANCE OPEN 2022; 10-11:100057. [PMID: 35707629 PMCID: PMC9191766 DOI: 10.1016/j.jmro.2022.100057] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Chromatin is a DNA-protein polymer that represents the functional form of the genome. The main building block of chromatin is the nucleosome, a structure that contains 147 base pairs of DNA and two copies each of the histone proteins H2A, H2B, H3 and H4. Previous work has shown that magic angle spinning (MAS) NMR spectroscopy can capture the nucleosome at high resolution although studies have been challenging due to low sensitivity, the presence of dynamic and rigid components, and the complex interaction networks of nucleosomes within the chromatin polymer. Here, we use dynamic nuclear polarization (DNP) to enhance the sensitivity of MAS NMR experiments of nucleosome arrays at 100 K and show that well-resolved 13C-13C MAS NMR correlations can be obtained much more efficiently. We evaluate the effect of temperature on the chemical shifts and linewidths in the spectra and demonstrate that changes are relatively minimal and clustered in regions of histone-DNA or histone-histone contacts. We also compare samples prepared with and without DNA and show that the low temperature 13C-13C correlations exhibit sufficient resolution to detect chemical shift changes and line broadening for residues that form the DNA-histone interface. On the other hand, we show that the measurement of DNP-enhanced 15N-13C histone-histone interactions within the nucleosome core is complicated by the natural 13C abundance network in the sample. Nevertheless, the enhanced sensitivity afforded by DNP can be used to detect long-range correlations between histone residues and DNA. Overall, our experiments demonstrate that DNP-enhanced MAS NMR spectroscopy of chromatin samples yields spectra with high resolution and sensitivity and can be used to capture functionally relevant protein-DNA interactions that have implications for gene regulation and genome organization.
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Affiliation(s)
| | | | - Galia T. Debelouchina
- Corresponding author: Galia Debelouchina, University of California, San Diego, Natural Sciences Building 4322, 9500 Gilman Dr., La Jolla, CA 92093, 858-534-3038,
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11
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Chow WY, De Paëpe G, Hediger S. Biomolecular and Biological Applications of Solid-State NMR with Dynamic Nuclear Polarization Enhancement. Chem Rev 2022; 122:9795-9847. [PMID: 35446555 DOI: 10.1021/acs.chemrev.1c01043] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Solid-state NMR spectroscopy (ssNMR) with magic-angle spinning (MAS) enables the investigation of biological systems within their native context, such as lipid membranes, viral capsid assemblies, and cells. However, such ambitious investigations often suffer from low sensitivity due to the presence of significant amounts of other molecular species, which reduces the effective concentration of the biomolecule or interaction of interest. Certain investigations requiring the detection of very low concentration species remain unfeasible even with increasing experimental time for signal averaging. By applying dynamic nuclear polarization (DNP) to overcome the sensitivity challenge, the experimental time required can be reduced by orders of magnitude, broadening the feasible scope of applications for biological solid-state NMR. In this review, we outline strategies commonly adopted for biological applications of DNP, indicate ongoing challenges, and present a comprehensive overview of biological investigations where MAS-DNP has led to unique insights.
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Affiliation(s)
- Wing Ying Chow
- Univ. Grenoble Alpes, CEA, CNRS, Interdisciplinary Research Institute of Grenoble (IRIG), Modeling and Exploration of Materials Laboratory (MEM), 38054 Grenoble, France.,Univ. Grenoble Alpes, CEA, CNRS, Inst. Biol. Struct. IBS, 38044 Grenoble, France
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, CEA, CNRS, Interdisciplinary Research Institute of Grenoble (IRIG), Modeling and Exploration of Materials Laboratory (MEM), 38054 Grenoble, France
| | - Sabine Hediger
- Univ. Grenoble Alpes, CEA, CNRS, Interdisciplinary Research Institute of Grenoble (IRIG), Modeling and Exploration of Materials Laboratory (MEM), 38054 Grenoble, France
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12
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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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13
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Perras FA, Paterson AL, Kobayashi T. Phase-sensitive γ-encoded recoupling of heteronuclear dipolar interactions and 1H chemical shift anisotropy. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2021; 111:101712. [PMID: 33450713 DOI: 10.1016/j.ssnmr.2020.101712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
γ-encoded recoupling sequences are known to produce strong amplitude modulations that lead to sharp doublets when Fourier transformed. These doublets depend very little on the recoupled tensor asymmetry and thus enable for the straightforward determination of dynamic order parameters. It can, however, be difficult to measure small anisotropies, or small order parameters, using such sequences; the resonances from the doublet may overlap with each other, or with the zero-frequency glitch. This limitation has prevented the widespread use of 1H chemical shift anisotropy (CSA) for the measurement of dynamics, particularly for CH protons which typically have CSAs of only a few ppm when immobile. Here, we introduce a simple modification to the traditional 1H CSA and proton-detected local field pulse sequences that enables the acquisition of a hypercomplex dataset and the removal of the uncorrelated magnetization that results in the zero-frequency glitch. These new sequences then yield a frequency shift in the indirect dimension, rather than a splitting, which is easily identifiable even in cases of weak interactions.
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14
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Gauto DF, Macek P, Barducci A, Fraga H, Hessel A, Terauchi T, Gajan D, Miyanoiri Y, Boisbouvier J, Lichtenecker R, Kainosho M, Schanda P. Aromatic Ring Dynamics, Thermal Activation, and Transient Conformations of a 468 kDa Enzyme by Specific 1H- 13C Labeling and Fast Magic-Angle Spinning NMR. J Am Chem Soc 2019; 141:11183-11195. [PMID: 31199882 DOI: 10.1021/jacs.9b04219] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Aromatic residues are located at structurally important sites of many proteins. Probing their interactions and dynamics can provide important functional insight but is challenging in large proteins. Here, we introduce approaches to characterize the dynamics of phenylalanine residues using 1H-detected fast magic-angle spinning (MAS) NMR combined with a tailored isotope-labeling scheme. Our approach yields isolated two-spin systems that are ideally suited for artifact-free dynamics measurements, and allows probing motions effectively without molecular weight limitations. The application to the TET2 enzyme assembly of ∼0.5 MDa size, the currently largest protein assigned by MAS NMR, provides insights into motions occurring on a wide range of time scales (picoseconds to milliseconds). We quantitatively probe ring-flip motions and show the temperature dependence by MAS NMR measurements down to 100 K. Interestingly, favorable line widths are observed down to 100 K, with potential implications for DNP NMR. Furthermore, we report the first 13C R1ρ MAS NMR relaxation-dispersion measurements and detect structural excursions occurring on a microsecond time scale in the entry pore to the catalytic chamber and at a trimer interface that was proposed as the exit pore. We show that the labeling scheme with deuteration at ca. 50 kHz MAS provides superior resolution compared to 100 kHz MAS experiments with protonated, uniformly 13C-labeled samples.
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Affiliation(s)
- Diego F Gauto
- Univ. Grenoble Alpes, CEA, CNRS , Institut de Biologie Structurale (IBS) , 71, avenue des martyrs , F-38044 Grenoble , France
| | - Pavel Macek
- Univ. Grenoble Alpes, CEA, CNRS , Institut de Biologie Structurale (IBS) , 71, avenue des martyrs , F-38044 Grenoble , France
| | - Alessandro Barducci
- Centre de Biochimie Structurale (CBS) , INSERM, CNRS, Université de Montpellier , Montpellier , France
| | - Hugo Fraga
- Univ. Grenoble Alpes, CEA, CNRS , Institut de Biologie Structurale (IBS) , 71, avenue des martyrs , F-38044 Grenoble , France.,Departamento de Biomedicina , Faculdade de Medicina da Universidade do Porto , Porto , Portugal.,i3S, Instituto de Investigação e Inovação em Saúde , Universidade do Porto , Porto , Portugal
| | - Audrey Hessel
- Univ. Grenoble Alpes, CEA, CNRS , Institut de Biologie Structurale (IBS) , 71, avenue des martyrs , F-38044 Grenoble , France
| | - Tsutomu Terauchi
- Graduate School of Science , Tokyo Metropolitan University , 1-1 Minami-ohsawa , Hachioji , Tokyo 192-0397 , Japan.,SI Innovation Center , Taiyo Nippon Sanso Corp. , 2008-2 Wada , Tama-city , Tokyo 206-0001 , Japan
| | - David Gajan
- Université de Lyon , Centre de RMN à Hauts Champs de Lyon CRMN, FRE 2034, Université de Lyon, CNRS, ENS Lyon, UCB Lyon 1 , 69100 Villeurbanne , France
| | - Yohei Miyanoiri
- Institute of Protein Research , Osaka University , 3-2 Yamadaoka , Suita , Osaka 565-0871 , Japan.,Structural Biology Research Center, Graduate School of Sciences , Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602 , Japan
| | - Jerome Boisbouvier
- Univ. Grenoble Alpes, CEA, CNRS , Institut de Biologie Structurale (IBS) , 71, avenue des martyrs , F-38044 Grenoble , France
| | - Roman Lichtenecker
- Institute of Organic Chemistry , University of Vienna , Währinger Str. 38 , 1090 Vienna , Austria
| | - Masatsune Kainosho
- Graduate School of Science , Tokyo Metropolitan University , 1-1 Minami-ohsawa , Hachioji , Tokyo 192-0397 , Japan.,Structural Biology Research Center, Graduate School of Sciences , Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602 , Japan
| | - Paul Schanda
- Univ. Grenoble Alpes, CEA, CNRS , Institut de Biologie Structurale (IBS) , 71, avenue des martyrs , F-38044 Grenoble , France
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15
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Aladin V, Corzilius B. Methyl dynamics in amino acids modulate heteronuclear cross relaxation in the solid state under MAS DNP. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 99:27-35. [PMID: 30865870 DOI: 10.1016/j.ssnmr.2019.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/20/2019] [Accepted: 02/20/2019] [Indexed: 05/09/2023]
Abstract
Dynamic Nuclear Polarization (DNP) is a wide-spread technique for sensitivity enhancement of MAS NMR. During a typical MAS DNP experiment, several mechanisms resulting in polarization transfer may be active at the same time. One such mechanism which is most commonly active but up to now mostly disregarded is SCREAM-DNP (Specific Cross Relaxation Enhancement by Active Motions under DNP). This effect is generally observed in direct DNP experiments if molecular dynamics are supporting heteronuclear cross relaxation similar to the nuclear Overhauser effect. We investigate this effect for the CH3 groups of all methyl-bearing amino acids (i.e., alanine, valine, leucine, isoleucine, threonine, and methionine). At the typical DNP temperature of ∼110 K the three-fold reorientation dynamics are still active, and efficient SCREAM-DNP is observed. We discuss variations in enhancement factors obtained by this effect in context of sample temperature and sterical hindrance of the methyl group. Next to the direct transfer to the methyl carbon, we also find evidence for much weaker transfer from the methyl protons directly to other carbons in the amino acid molecule and succeed to correlate build-up dynamics with the CH dipole coupling which is modulated by the CH3 orientation. Besides methyl dynamics we also identify ring dynamics within proline as a source of SCREAM-DNP. Our results are the first step towards utilization of this effect as a specific probing techniqueusing methyl groups in protein systems.
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Affiliation(s)
- Victoria Aladin
- Institute of Physical Chemistry, Institute of Biophysical Chemistry, Biomolecular Magnetic Resonance Center (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 7-9, 60438, Frankfurt, Germany
| | - Björn Corzilius
- Institute of Physical Chemistry, Institute of Biophysical Chemistry, Biomolecular Magnetic Resonance Center (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 7-9, 60438, Frankfurt, Germany.
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16
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Ackermann BE, Debelouchina GT. Heterochromatin Protein HP1α Gelation Dynamics Revealed by Solid‐State NMR Spectroscopy. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201901141] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Bryce E. Ackermann
- Department of Chemistry and BiochemistryUniversity of California, San Diego 9500 Gilman Dr. La Jolla CA 92093 USA
| | - Galia T. Debelouchina
- Department of Chemistry and BiochemistryUniversity of California, San Diego 9500 Gilman Dr. La Jolla CA 92093 USA
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17
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Ackermann BE, Debelouchina GT. Heterochromatin Protein HP1α Gelation Dynamics Revealed by Solid-State NMR Spectroscopy. Angew Chem Int Ed Engl 2019; 58:6300-6305. [PMID: 30845353 DOI: 10.1002/anie.201901141] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/07/2019] [Indexed: 11/12/2022]
Abstract
Heterochromatin protein 1α (HP1α) undergoes liquid-liquid phase separation (LLPS) and forms liquid droplets and gels in vitro, properties that also appear to be central to its biological function in heterochromatin compaction and regulation. Here we use solid-state NMR spectroscopy to track the conformational dynamics of phosphorylated HP1α during its transformation from the liquid to the gel state. Using experiments designed to probe distinct dynamic modes, we identify regions with varying mobilities within HP1α molecules and show that specific serine residues uniquely contribute to gel formation. The addition of chromatin disturbs the gelation process while preserving the conformational dynamics within individual bulk HP1α molecules. Our study provides a glimpse into the dynamic architecture of dense HP1α phases and showcases the potential of solid-state NMR to detect an elusive biophysical regime of phase separating biomolecules.
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Affiliation(s)
- Bryce E Ackermann
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, USA
| | - Galia T Debelouchina
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, USA
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18
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Leroy C, Bryce DL. Recent advances in solid-state nuclear magnetic resonance spectroscopy of exotic nuclei. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:160-199. [PMID: 30527135 DOI: 10.1016/j.pnmrs.2018.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/18/2018] [Accepted: 08/10/2018] [Indexed: 06/09/2023]
Abstract
We present a review of recent advances in solid-state nuclear magnetic resonance (SSNMR) studies of exotic nuclei. Exotic nuclei may be spin-1/2 or quadrupolar, and typically have low gyromagnetic ratios, low natural abundances, large quadrupole moments (when I > 1/2), or some combination of these properties, generally resulting in low receptivities and/or prohibitively broad line widths. Some nuclides are little studied for other reasons, also rendering them somewhat exotic. We first discuss some of the recent progress in pulse sequences and hardware development which continues to enable researchers to study new kinds of materials as well as previously unfeasible nuclei. This is followed by a survey of applications to a wide range of exotic nuclei (including e.g., 9Be, 25Mg, 33S, 39K, 43Ca, 47/49Ti, 53Cr, 59Co, 61Ni, 67Zn, 73Ge, 75As, 87Sr, 115In, 119Sn, 121/123Sb, 135/137Ba, 185/187Re, 209Bi), most of them quadrupolar. The scope of the review is the past ten years, i.e., 2007-2017.
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Affiliation(s)
- César Leroy
- Department of Chemistry and Biomolecular Sciences & Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N 6N5, Canada
| | - David L Bryce
- Department of Chemistry and Biomolecular Sciences & Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N 6N5, Canada.
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19
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Matlahov I, van der Wel PCA. Hidden motions and motion-induced invisibility: Dynamics-based spectral editing in solid-state NMR. Methods 2018; 148:123-135. [PMID: 29702226 DOI: 10.1016/j.ymeth.2018.04.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/05/2018] [Accepted: 04/16/2018] [Indexed: 10/17/2022] Open
Abstract
Solid-state nuclear magnetic resonance (ssNMR) spectroscopy enables the structural characterization of a diverse array of biological assemblies that include amyloid fibrils, non-amyloid aggregates, membrane-associated proteins and viral capsids. Such biological samples feature functionally relevant molecular dynamics, which often affect different parts of the sample in different ways. Solid-state NMR experiments' sensitivity to dynamics represents a double-edged sword. On the one hand, it offers a chance to measure dynamics in great detail. On the other hand, certain types of motion lead to signal loss and experimental inefficiencies that at first glance interfere with the application of ssNMR to overly dynamic proteins. Dynamics-based spectral editing (DYSE) ssNMR methods leverage motion-dependent signal losses to simplify spectra and enable the study of sub-structures with particular motional properties.
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Affiliation(s)
- Irina Matlahov
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15213, USA
| | - Patrick C A van der Wel
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15213, USA; Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
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20
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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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21
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Fritzsching KJ, Itin B, McDermott AE. N,N-Diethylmethylamine as lineshape standard for NMR above 130 K. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 287:110-112. [PMID: 29335163 PMCID: PMC5821130 DOI: 10.1016/j.jmr.2017.12.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/24/2017] [Accepted: 12/30/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate that N,N-Diethylmethylamine (DEMA) is a useful compound for shimming the magnetic field when doing NMR experiments at room temperature and 130 K, near the temperature used in many dynamic nuclear polarization (DNP) experiments. The resonance assigned to the N-methyl carbon in DEMA at 14.7 T and 140 K has a full-width-half-max linewidth of <4 Hz and has a spin-lattice relaxation time of 0.17 ± 0.03 s.
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Affiliation(s)
- Keith J Fritzsching
- Department of Chemistry, Columbia University, New York, NY 10027, United States
| | - Boris Itin
- New York Structural Biology Center, New York, NY 10027, United States
| | - Ann E McDermott
- Department of Chemistry, Columbia University, New York, NY 10027, United States.
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22
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Vugmeyster L, Ostrovsky D, Hoatson GL, Qiang W, Falconer IB. Solvent-Driven Dynamical Crossover in the Phenylalanine Side-Chain from the Hydrophobic Core of Amyloid Fibrils Detected by 2H NMR Relaxation. J Phys Chem B 2017; 121:7267-7275. [PMID: 28699757 PMCID: PMC5567839 DOI: 10.1021/acs.jpcb.7b04726] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aromatic residues are important markers of dynamical changes in proteins' hydrophobic cores. In this work we investigated the dynamics of the F19 side-chain in the core of amyloid fibrils across a wide temperature range of 300 to 140 K. We utilized solid-state 2H NMR relaxation to demonstrate the presence of a solvent-driven dynamical crossover between different motional regimes, often also referred to as the dynamical transition. In particular, the dynamics are dominated by small-angle fluctuations at low temperatures and by π-flips of the aromatic ring at high temperatures. The crossover temperature is more than 43 degrees lower for the hydrated state of the fibrils compared to the dry state, indicating that interactions with water facilitate π-flips. Further, crossover temperatures are shown to be very sensitive to polymorphic states of the fibrils, such as the 2-fold and 3-fold symmetric morphologies of the wild-type protein as well as D23N mutant protofibrils. We speculate that these differences can be attributed, at least partially, to enhanced interactions with water in the 3-fold polymorph, which has been shown to have a water-accessible cavity. Combined with previous studies of methyl group dynamics, the results highlight the presence of multiple dynamics modes in the core of the fibrils, which was originally believed to be quite rigid.
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Affiliation(s)
- Liliya Vugmeyster
- Department of Chemistry, University of Colorado at Denver, Denver, CO 80204
| | - Dmitry Ostrovsky
- Department of Mathematics, University of Colorado at Denver, Denver, CO 80204
| | - Gina L. Hoatson
- Department of Physics, College of William and Mary, Williamsburg, Virginia, 23187
| | - Wei Qiang
- Department of Chemistry, Binghamton University, Binghamton, NY 13902
| | - Isaac B. Falconer
- Department of Chemistry, University of Colorado at Denver, Denver, CO 80204
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23
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Ni QZ, Markhasin E, Can TV, Corzilius B, Tan KO, Barnes AB, Daviso E, Su Y, Herzfeld J, Griffin RG. Peptide and Protein Dynamics and Low-Temperature/DNP Magic Angle Spinning NMR. J Phys Chem B 2017; 121:4997-5006. [PMID: 28437077 DOI: 10.1021/acs.jpcb.7b02066] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In DNP MAS NMR experiments at ∼80-110 K, the structurally important -13CH3 and -15NH3+ signals in MAS spectra of biological samples disappear due to the interference of the molecular motions with the 1H decoupling. Here we investigate the effect of these dynamic processes on the NMR line shapes and signal intensities in several typical systems: (1) microcrystalline APG, (2) membrane protein bR, (3) amyloid fibrils PI3-SH3, (4) monomeric alanine-CD3, and (5) the protonated and deuterated dipeptide N-Ac-VL over 78-300 K. In APG, the three-site hopping of the Ala-Cβ peak disappears completely at 112 K, concomitant with the attenuation of CP signals from other 13C's and 15N's. Similarly, the 15N signal from Ala-NH3+ disappears at ∼173 K, concurrent with the attenuation in CP experiments of other 15N's as well as 13C's. In bR and PI3-SH3, the methyl groups are attenuated at ∼95 K, while all other 13C's remain unaffected. However, both systems exhibit substantial losses of intensity at ∼243 K. Finally, with spectra of Ala and N-Ac-VL, we show that it is possible to extract site specific dynamic data from the temperature dependence of the intensity losses. Furthermore, 2H labeling can assist with recovering the spectral intensity. Thus, our study provides insight into the dynamic behavior of biological systems over a wide range of temperatures, and serves as a guide to optimizing the sensitivity and resolution of structural data in low temperature DNP MAS NMR spectra.
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Affiliation(s)
- Qing Zhe Ni
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Evgeny Markhasin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Thach V Can
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Björn Corzilius
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Kong Ooi Tan
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Alexander B Barnes
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Eugenio Daviso
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Brandeis University , Waltham, Massachusetts 02454, United States
| | - Yongchao Su
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Judith Herzfeld
- Department of Chemistry, Brandeis University , Waltham, Massachusetts 02454, United States
| | - Robert G Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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24
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Mandal A, Boatz JC, Wheeler TB, van der Wel PCA. On the use of ultracentrifugal devices for routine sample preparation in biomolecular magic-angle-spinning NMR. JOURNAL OF BIOMOLECULAR NMR 2017; 67:165-178. [PMID: 28229262 PMCID: PMC5445385 DOI: 10.1007/s10858-017-0089-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/19/2017] [Indexed: 05/07/2023]
Abstract
A number of recent advances in the field of magic-angle-spinning (MAS) solid-state NMR have enabled its application to a range of biological systems of ever increasing complexity. To retain biological relevance, these samples are increasingly studied in a hydrated state. At the same time, experimental feasibility requires the sample preparation process to attain a high sample concentration within the final MAS rotor. We discuss these considerations, and how they have led to a number of different approaches to MAS NMR sample preparation. We describe our experience of how custom-made (or commercially available) ultracentrifugal devices can facilitate a simple, fast and reliable sample preparation process. A number of groups have since adopted such tools, in some cases to prepare samples for sedimentation-style MAS NMR experiments. Here we argue for a more widespread adoption of their use for routine MAS NMR sample preparation.
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Affiliation(s)
- Abhishek Mandal
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Jennifer C Boatz
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Travis B Wheeler
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15260, USA
| | - Patrick C A van der Wel
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA.
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25
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Märker K, Hediger S, De Paëpe G. Efficient 2D double-quantum solid-state NMR spectroscopy with large spectral widths. Chem Commun (Camb) 2017; 53:9155-9158. [DOI: 10.1039/c7cc04890d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
STiC phase shifts enable the use of supercycled recoupling sequences for recording 2D DQ–SQ correlation spectra with arbitrary spectral widths.
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26
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Bauer T, Dotta C, Balacescu L, Gath J, Hunkeler A, Böckmann A, Meier BH. Line-Broadening in Low-Temperature Solid-State NMR Spectra of Fibrils. JOURNAL OF BIOMOLECULAR NMR 2017; 67:51-61. [PMID: 28161758 DOI: 10.1007/s10858-016-0083-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 12/15/2016] [Indexed: 06/06/2023]
Abstract
The temperature-dependent resonance-line broadening of HET-s(218-289) in its amyloid form is investigated in the range between 110 K and 280 K. Significant differences are observed between residues in the structured hydrophobic triangular core, which are broadened the least and can be detected down to 100 K, and in the solvent-exposed parts, which are broadened the most and often disappear from the observed spectrum around 200 K. Below the freezing of the bulk water, around 273 K, the protein fibrils are still surrounded by a layer of mobile water whose thickness decreases with temperature, leading to drying out of the fibrils.
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Affiliation(s)
- Thomas Bauer
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland
| | - Claudio Dotta
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland
| | - Livia Balacescu
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland
| | - Julia Gath
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland
| | - Andreas Hunkeler
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland
| | - Anja Böckmann
- Institut de Biologie et Chimie des Protéines, UMR 5086 CNRS, Université de Lyon 1, 7 passage du Vercors, 69367, Lyon, France.
| | - Beat H Meier
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland.
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27
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Lehnert E, Mao J, Mehdipour AR, Hummer G, Abele R, Glaubitz C, Tampé R. Antigenic Peptide Recognition on the Human ABC Transporter TAP Resolved by DNP-Enhanced Solid-State NMR Spectroscopy. J Am Chem Soc 2016; 138:13967-13974. [DOI: 10.1021/jacs.6b07426] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
| | | | - Ahmad Reza Mehdipour
- Department
of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Str.
3, 60438 Frankfurt
am Main, Germany
| | - Gerhard Hummer
- Department
of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Str.
3, 60438 Frankfurt
am Main, Germany
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28
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Abstract
The structure and dynamics of the bound water in barium chlorate monohydrate were studied with (17)O nuclear magnetic resonance (NMR) spectroscopy in samples that are stationary and spinning at the magic-angle in magnetic fields ranging from 14.1 to 21.1 T. (17)O NMR parameters of the water were determined, and the effects of torsional oscillations of the water molecule on the (17)O quadrupolar coupling constant (CQ) were delineated with variable temperature MAS NMR. With decreasing temperature and reduction of the librational motion, we observe an increase in the experimentally measured CQ explaining the discrepancy between experiments and predictions from density functional theory. In addition, at low temperatures and in the absence of (1)H decoupling, we observe a well-resolved (1)H-(17)O dipole splitting in the spectra, which provides information on the structure of the H2O molecule. The splitting arises because of the homogeneous nature of the coupling between the two (1)H-(17)O dipoles and the (1)H-(1)H dipole.
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Affiliation(s)
- Eric G. Keeler
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | | | - Robert G. Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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29
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Matsuki Y, Idehara T, Fukazawa J, Fujiwara T. Advanced instrumentation for DNP-enhanced MAS NMR for higher magnetic fields and lower temperatures. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 264:107-115. [PMID: 26920836 DOI: 10.1016/j.jmr.2016.01.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/14/2016] [Accepted: 01/19/2016] [Indexed: 05/03/2023]
Abstract
Sensitivity enhancement of MAS NMR using dynamic nuclear polarization (DNP) is gaining importance at moderate fields (B0<9T) and temperatures (T>90K) with potential applications in chemistry and material sciences. However, considering the ever-increasing size and complexity of the systems to be studied, it is crucial to establish DNP under higher field conditions, where the spectral resolution and the basic NMR sensitivity tend to improve. In this perspective, we overview our recent efforts on hardware developments, specifically targeted on improving DNP MAS NMR at high fields. It includes the development of gyrotrons that enable continuous frequency tuning and rapid frequency modulation for our 395 GHz-600 MHz and 460 GHz-700 MHz DNP NMR spectrometers. The latter 700 MHz system involves two gyrotrons and a quasi-optical transmission system that combines two independent sub-millimeter waves into a single dichromic wave. We also describe two cryogenic MAS NMR probe systems operating, respectively, at T ∼ 100K and ∼ 30K. The latter system utilizes a novel closed-loop helium recirculation mechanism, achieving cryogenic MAS without consuming any cryogen. These instruments altogether should promote high-field DNP toward more efficient, reliable and affordable technology. Some experimental DNP results obtained with these instruments are presented.
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Affiliation(s)
- Yoh Matsuki
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Toshitaka Idehara
- Research Center for Development of Far-Infrared Region, University of Fukui, Bunkyo 3-9-1, Fukui 910-8507, Japan
| | - Jun Fukazawa
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Toshimichi Fujiwara
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
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30
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Vugmeyster L, Ostrovsky D, Villafranca T, Sharp J, Xu W, Lipton AS, Hoatson GL, Vold RL. Dynamics of Hydrophobic Core Phenylalanine Residues Probed by Solid-State Deuteron NMR. J Phys Chem B 2015; 119:14892-904. [PMID: 26529128 PMCID: PMC4970646 DOI: 10.1021/acs.jpcb.5b09299] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We conducted a detailed investigation of the dynamics of two phenylalanine side chains in the hydrophobic core of the villin headpiece subdomain protein (HP36) in the hydrated powder state over the 298-80 K temperature range. Our main tools were static deuteron NMR measurements of longitudinal relaxation and line shapes supplemented with computational modeling. The temperature dependence of the relaxation times reveals the presence of two main mechanisms that can be attributed to the ring-flips, dominating at high temperatures, and small-angle fluctuations, dominating at low temperatures. The relaxation is nonexponential at all temperatures with the extent of nonexponentiality increasing from higher to lower temperatures. This behavior suggests a distribution of conformers with unique values of activation energies. The central values of the activation energies for the ring-flipping motions are among the smallest reported for aromatic residues in peptides and proteins and point to a very mobile hydrophobic core. The analysis of the widths of the distributions, in combination with the earlier results on the dynamics of flanking methyl groups (Vugmeyster et al. J. Phys. Chem. B 2013, 117, 6129-6137), suggests that the hydrophobic core undergoes slow concerted fluctuations. There is a pronounced effect of dehydration on the ring-flipping motions, which shifts the distribution toward more rigid conformers. The crossover temperature between the regions of dominance of the small-angle fluctuations and ring-flips shifts from 195 K in the hydrated protein to 278 K in the dry one. This result points to the role of solvent in softening the core and highlights aromatic residues as markers of the protein dynamical transitions.
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Affiliation(s)
| | | | | | - Janelle Sharp
- University of Alaska Anchorage, Anchorage, Alaska, 99508
| | - Wei Xu
- College of William and Mary, Williamsburg, Virginia, 23187
| | - Andrew S. Lipton
- Pacific Northwest National Laboratory, Richland, Washington, 99354
| | | | - Robert L. Vold
- College of William and Mary, Williamsburg, Virginia, 23187
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31
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Frederick KK, Michaelis VK, Corzilius B, Ong TC, Jacavone AC, Griffin RG, Lindquist S. Sensitivity-enhanced NMR reveals alterations in protein structure by cellular milieus. Cell 2015; 163:620-8. [PMID: 26456111 PMCID: PMC4621972 DOI: 10.1016/j.cell.2015.09.024] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 07/03/2015] [Accepted: 08/26/2015] [Indexed: 12/11/2022]
Abstract
Biological processes occur in complex environments containing a myriad of potential interactors. Unfortunately, limitations on the sensitivity of biophysical techniques normally restrict structural investigations to purified systems, at concentrations that are orders of magnitude above endogenous levels. Dynamic nuclear polarization (DNP) can dramatically enhance the sensitivity of nuclear magnetic resonance (NMR) spectroscopy and enable structural studies in biologically complex environments. Here, we applied DNP NMR to investigate the structure of a protein containing both an environmentally sensitive folding pathway and an intrinsically disordered region, the yeast prion protein Sup35. We added an exogenously prepared isotopically labeled protein to deuterated lysates, rendering the biological environment "invisible" and enabling highly efficient polarization transfer for DNP. In this environment, structural changes occurred in a region known to influence biological activity but intrinsically disordered in purified samples. Thus, DNP makes structural studies of proteins at endogenous levels in biological contexts possible, and such contexts can influence protein structure.
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Affiliation(s)
| | - Vladimir K Michaelis
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Björn Corzilius
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ta-Chung Ong
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Angela C Jacavone
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert G Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Susan Lindquist
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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32
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Matsuki Y, Nakamura S, Fukui S, Suematsu H, Fujiwara T. Closed-cycle cold helium magic-angle spinning for sensitivity-enhanced multi-dimensional solid-state NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 259:76-81. [PMID: 26302269 DOI: 10.1016/j.jmr.2015.08.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 08/04/2015] [Indexed: 05/21/2023]
Abstract
Magic-angle spinning (MAS) NMR is a powerful tool for studying molecular structure and dynamics, but suffers from its low sensitivity. Here, we developed a novel helium-cooling MAS NMR probe system adopting a closed-loop gas recirculation mechanism. In addition to the sensitivity gain due to low temperature, the present system has enabled highly stable MAS (vR=4-12 kHz) at cryogenic temperatures (T=35-120 K) for over a week without consuming helium at a cost for electricity of 16 kW/h. High-resolution 1D and 2D data were recorded for a crystalline tri-peptide sample at T=40 K and B0=16.4 T, where an order of magnitude of sensitivity gain was demonstrated versus room temperature measurement. The low-cost and long-term stable MAS strongly promotes broader application of the brute-force sensitivity-enhanced multi-dimensional MAS NMR, as well as dynamic nuclear polarization (DNP)-enhanced NMR in a temperature range lower than 100 K.
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Affiliation(s)
- Yoh Matsuki
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shinji Nakamura
- JEOL RESONANCE Inc., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan
| | - Shigeo Fukui
- Cryovac Corporation, 2-12-14 Chibune, Nishi Yodogawa, Osaka 555-0013, Japan
| | - Hiroto Suematsu
- JEOL RESONANCE Inc., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan
| | - Toshimichi Fujiwara
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
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33
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Khodadadi S, Sokolov AP. Protein dynamics: from rattling in a cage to structural relaxation. SOFT MATTER 2015; 11:4984-4998. [PMID: 26027652 DOI: 10.1039/c5sm00636h] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present an overview of protein dynamics based mostly on results of neutron scattering, dielectric relaxation spectroscopy and molecular dynamics simulations. We identify several major classes of protein motions on the time scale from faster than picoseconds to several microseconds, and discuss the coupling of these processes to solvent dynamics. Our analysis suggests that the microsecond backbone relaxation process might be the main structural relaxation of the protein that defines its glass transition temperature, while faster processes present some localized secondary relaxations. Based on the overview, we formulate a general picture of protein dynamics and discuss the challenges in this field.
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Affiliation(s)
- S Khodadadi
- Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
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34
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Lewandowski JR, Halse ME, Blackledge M, Emsley L. Direct observation of hierarchical protein dynamics. Science 2015; 348:578-81. [DOI: 10.1126/science.aaa6111] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Nishiyama Y, Kobayashi T, Malon M, Singappuli-Arachchige D, Slowing II, Pruski M. Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100 kHz MAS. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 66-67:56-61. [PMID: 25773137 DOI: 10.1016/j.ssnmr.2015.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 02/05/2015] [Accepted: 02/07/2015] [Indexed: 06/04/2023]
Abstract
Two-dimensional (1)H{(13)C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in (1)H dimension without resorting to (1)H-(1)H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. The HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.
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Affiliation(s)
- Y Nishiyama
- JEOL Resonance Inc., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan.
| | - T Kobayashi
- U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA
| | - M Malon
- JEOL Resonance Inc., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - D Singappuli-Arachchige
- U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA; Department of Chemistry, Iowa State University, Ames, IA 50011-3020, USA
| | - I I Slowing
- U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA; Department of Chemistry, Iowa State University, Ames, IA 50011-3020, USA
| | - M Pruski
- U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA; Department of Chemistry, Iowa State University, Ames, IA 50011-3020, USA.
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36
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Lee D, Hediger S, De Paëpe G. Is solid-state NMR enhanced by dynamic nuclear polarization? SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 66-67:6-20. [PMID: 25779337 DOI: 10.1016/j.ssnmr.2015.01.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 05/03/2023]
Abstract
The recent trend of high-field (~5-20 T), low-temperature (~100 K) ssNMR combined with dynamic nuclear polarization (DNP) under magic angle spinning (MAS) conditions is analyzed. A brief overview of the current theory of hyperpolarization for so-called MAS-DNP experiments is given, along with various reasons why the DNP-enhancement, the ratio of the NMR signal intensities obtained in the presence and absence of microwave irradiation suitable for hyperpolarization, should not be used alone to gauge the value of performing MAS-DNP experiments relative to conventional ssNMR. This is demonstrated through a dissection of the current conditions required for MAS-DNP with particular attention to resulting absolute sensitivities and spectral resolution. Consequently, sample preparation methods specifically avoiding the surplus of glass-forming solvents so as to improve the absolute sensitivity and resolution are discussed, as are samples that are intrinsically pertinent for MAS-DNP studies (high surface area, amorphous, and porous). Owing to their pertinence, examples of recent applications on these types of samples where chemically-relevant information has been obtained that would have been impossible without the sensitivity increases bestowed by MAS-DNP are also detailed. Additionally, a promising further implementation for MAS-DNP is exampled, whereby the sensitivity improvements shown for (correlation) spectroscopy of nuclei at low natural isotopic abundance, facilitate internuclear distance measurements, especially for long distances (absence of dipolar truncation). Finally, we give some speculative perspectives for MAS-DNP.
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Affiliation(s)
- Daniel Lee
- Univ. Grenoble Alpes, INAC, SCIB, F-38000 Grenoble, France; CEA, INAC, SCIB, F-38000 Grenoble, France.
| | - Sabine Hediger
- Univ. Grenoble Alpes, INAC, SCIB, F-38000 Grenoble, France; CEA, INAC, SCIB, F-38000 Grenoble, France; CNRS, SCIB, F-38000 Grenoble, France
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, INAC, SCIB, F-38000 Grenoble, France; CEA, INAC, SCIB, F-38000 Grenoble, France
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37
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Su Y, Andreas L, Griffin RG. Magic angle spinning NMR of proteins: high-frequency dynamic nuclear polarization and (1)H detection. Annu Rev Biochem 2015; 84:465-97. [PMID: 25839340 DOI: 10.1146/annurev-biochem-060614-034206] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magic angle spinning (MAS) NMR studies of amyloid and membrane proteins and large macromolecular complexes are an important new approach to structural biology. However, the applicability of these experiments, which are based on (13)C- and (15)N-detected spectra, would be enhanced if the sensitivity were improved. Here we discuss two advances that address this problem: high-frequency dynamic nuclear polarization (DNP) and (1)H-detected MAS techniques. DNP is a sensitivity enhancement technique that transfers the high polarization of exogenous unpaired electrons to nuclear spins via microwave irradiation of electron-nuclear transitions. DNP boosts NMR signal intensities by factors of 10(2) to 10(3), thereby overcoming NMR's inherent low sensitivity. Alternatively, it permits structural investigations at the nanomolar scale. In addition, (1)H detection is feasible primarily because of the development of MAS rotors that spin at frequencies of 40 to 60 kHz or higher and the preparation of extensively (2)H-labeled proteins.
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Affiliation(s)
- Yongchao Su
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139;
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38
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Markin AV, Markhasin E, Sologubov SS, Ni QZ, Smirnova NN, Griffin RG. Low-temperature polymorphic phase transition in a crystalline tripeptide L-Ala-L-Pro-Gly·H2O revealed by adiabatic calorimetry. J Phys Chem B 2015; 119:1787-92. [PMID: 25588051 DOI: 10.1021/jp508710g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We demonstrate application of precise adiabatic vacuum calorimetry to observation of phase transition in the tripeptide L-alanyl-L-prolyl-glycine monohydrate (APG) from 6 to 320 K and report the standard thermodynamic properties of the tripeptide in the entire range. Thus, the heat capacity of APG was measured by adiabatic vacuum calorimetry in the above temperature range. The tripeptide exhibits a reversible first-order solid-to-solid phase transition characterized by strong thermal hysteresis. We report the standard thermodynamic characteristics of this transition and show that differential scanning calorimetry can reliably characterize the observed phase transition with <5 mg of the sample. Additionally, the standard entropy of formation from the elemental substances and the standard entropy of hypothetical reaction of synthesis from the amino acids at 298.15 K were calculated for the studied tripeptide.
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Affiliation(s)
- Alexey V Markin
- Lobachevsky State University of Nizhny Novgorod , Gagarin Pr. 23/5, Nizhny Novgorod 603950, Russia
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39
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Lee M, Hong M. Cryoprotection of lipid membranes for high-resolution solid-state NMR studies of membrane peptides and proteins at low temperature. JOURNAL OF BIOMOLECULAR NMR 2014; 59:263-77. [PMID: 25015530 PMCID: PMC4160392 DOI: 10.1007/s10858-014-9845-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 07/03/2014] [Indexed: 05/09/2023]
Abstract
Solid-state NMR spectra of membrane proteins often show significant line broadening at cryogenic temperatures. Here we investigate the effects of several cryoprotectants to preserve the spectral resolution of lipid membranes and membrane peptides at temperatures down to ~200 K. Trehalose, glycerol, dimethylsulfoxide (DMSO), dimethylformamide (DMF), and polyethylene glycol (PEG), were chosen. These compounds are commonly used in protein crystallography and cryobiology. 13C and 1H magic-angle-spinning spectra of several types of lipid membranes show that DMSO provides the best resolution enhancement over unprotected membranes and also best retards ice formation at low temperature. DMF and PEG-400 show slightly weaker cryoprotection, while glycerol and trehalose neither prevent membrane line broadening nor prevent ice formation under the conditions of our study. Neutral saturated-chain phospholipids are the most amenable to cryoprotection, whereas negatively charged and unsaturated lipids attenuate cryoprotection. 13C-1H dipolar couplings and 31P chemical shift anisotropies indicate that high spectral resolution at low temperature is correlated with stronger immobilization of the lipids at high temperature, indicating that line narrowing results from reduction of the conformational space sampled by the lipid molecules at high temperature. DMSO selectively narrowed the linewidths of the most disordered residues in the influenza M2 transmembrane peptide, while residues that exhibit narrow linewidths in the unprotected membrane are less impacted. A relatively rigid β-hairpin antimicrobial peptide, PG-1, showed a linewidth increase of ~0.5 ppm over a ~70 K temperature drop both with and without cryoprotection. Finally, a short-chain saturated lipid, DLPE, exhibits excellent linewidths, suggesting that it may be a good medium for membrane protein structure determination. The three best cryoprotectants found in this work-DMSO, PEG, and DMF-should be useful for low-temperature membrane-protein structural studies by SSNMR without compromising spectral resolution.
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Affiliation(s)
| | - Mei Hong
- Corresponding author: Mei Hong, Tel: 515-294-3521, Fax: 515-294-0105,
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40
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Markin AV, Markhasin E, Sologubov S, Smirnova NN, Griffin RG. Standard Thermodynamic Functions of Tripeptides N-Formyl-l-methionyl-l-leucyl-l-phenylalaninol and N-Formyl-l-methionyl-l-leucyl-l-phenylalanine Methyl Ester. JOURNAL OF CHEMICAL AND ENGINEERING DATA 2014; 59:1240-1246. [PMID: 24803685 PMCID: PMC3993880 DOI: 10.1021/je400879v] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 02/26/2014] [Indexed: 06/03/2023]
Abstract
The heat capacities of tripeptides N-formyl-l-methionyl-l-leucyl-l-phenylalaninol (N-f-MLF-OH) and N-formyl-l-methionyl-l-leucyl-l-phenylalanine methyl ester (N-f-MLF-OMe) were measured by precision adiabatic vacuum calorimetry over the temperature range from T = (6 to 350) K. The tripeptides were stable over this temperature range, and no phase change, transformation, association, or thermal decomposition was observed. The standard thermodynamic functions: molar heat capacity Cp,m, enthalpy H(T) - H(0), entropy S(T), and Gibbs energy G(T) - H(0) of peptides were calculated over the range from T = (0 to 350) K. The low-temperature (T ≤ 50 K) heat capacities dependencies were analyzed using the Debye's and the multifractal theories. The standard entropies of formation of peptides at T = 298.15 K were calculated.
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Affiliation(s)
- Alexey V. Markin
- Lobachevsky
State University of Nizhni Novgorod, 23/5 Gagarin Avenue, 603950, Nizhni Novgorod, Russia
| | - Evgeny Markhasin
- Massachusetts
Institute of Technology, 150 Albany Street, Cambridge, Massachusetts 02139, United States
| | - Semen
S. Sologubov
- Lobachevsky
State University of Nizhni Novgorod, 23/5 Gagarin Avenue, 603950, Nizhni Novgorod, Russia
| | - Natalia N. Smirnova
- Lobachevsky
State University of Nizhni Novgorod, 23/5 Gagarin Avenue, 603950, Nizhni Novgorod, Russia
| | - Robert G. Griffin
- Massachusetts
Institute of Technology, 150 Albany Street, Cambridge, Massachusetts 02139, United States
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41
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Michaelis VK, Ong TC, Kiesewetter MK, Frantz DK, Walish JJ, Ravera E, Luchinat C, Swager TM, Griffin RG. Topical Developments in High-Field Dynamic Nuclear Polarization. Isr J Chem 2014; 54:207-221. [PMID: 25977588 DOI: 10.1002/ijch.201300126] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We report our recent efforts directed at improving high-field DNP experiments. We investigated a series of thiourea nitroxide radicals and the associated DNP enhancements ranging from ε = 25 to 82 that demonstrate the impact of molecular structure on performance. We directly polarized low-gamma nuclei including 13C, 2H, and 17O using trityl via the cross effect. We discuss a variety of sample preparation techniques for DNP with emphasis on the benefit of methods that do not use a glass-forming cryoprotecting matrix. Lastly, we describe a corrugated waveguide for use in a 700 MHz / 460 GHz DNP system that improves microwave delivery and increases enhancements up to 50%.
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Affiliation(s)
- Vladimir K Michaelis
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Ta-Chung Ong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Matthew K Kiesewetter
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Derik K Frantz
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Joseph J Walish
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Enrico Ravera
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM) University of Florence, 50019 Sesto Fiorentino (FI), Italy
| | - Claudio Luchinat
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center (CERM) University of Florence, 50019 Sesto Fiorentino (FI), Italy
| | - Timothy M Swager
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Robert G Griffin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.,Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
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42
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Concistrè M, Carignani E, Borsacchi S, Johannessen OG, Mennucci B, Yang Y, Geppi M, Levitt MH. Freezing of Molecular Motions Probed by Cryogenic Magic Angle Spinning NMR. J Phys Chem Lett 2014; 5:512-516. [PMID: 26276602 DOI: 10.1021/jz4026276] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Cryogenic magic angle spinning makes it possible to obtain the NMR spectra of solids at temperatures low enough to freeze out most molecular motions. We have applied cryogenic magic angle spinning NMR to a crystalline small-molecule solid (ibuprofen sodium salt), which displays a variety of molecular dynamics. Magic angle (13)C NMR spectra are shown for a wide range of temperatures, including in the cryogenic regime down to 20 K. The hydrophobic and hydrophilic regions of the molecular structure display different behavior in the cryogenic regime, with the hydrophilic region remaining well-structured, while the hydrophobic region exhibits a broad frozen conformational distribution.
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Affiliation(s)
- Maria Concistrè
- †School of Chemistry, University of Southampton, SO17 1BJ Southampton, United Kingdom
| | - Elisa Carignani
- ‡Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy
| | - Silvia Borsacchi
- ‡Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy
| | - Ole G Johannessen
- †School of Chemistry, University of Southampton, SO17 1BJ Southampton, United Kingdom
| | - Benedetta Mennucci
- ‡Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy
| | - Yifeng Yang
- §School of Engineering Science, University of Southampton, Southampton, United Kingdom
| | - Marco Geppi
- ‡Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy
| | - Malcolm H Levitt
- †School of Chemistry, University of Southampton, SO17 1BJ Southampton, United Kingdom
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Ong YS, Lakatos A, Becker-Baldus J, Pos KM, Glaubitz C. Detecting substrates bound to the secondary multidrug efflux pump EmrE by DNP-enhanced solid-state NMR. J Am Chem Soc 2013; 135:15754-62. [PMID: 24047229 DOI: 10.1021/ja402605s] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Escherichia coli EmrE, a homodimeric multidrug antiporter, has been suggested to offer a convenient paradigm for secondary transporters due to its small size. It contains four transmembrane helices and forms a functional dimer. We have probed the specific binding of substrates TPP(+) and MTP(+) to EmrE reconstituted into 1,2-dimyristoyl-sn-glycero-3-phosphocholine liposomes by (31)P MAS NMR. Our NMR data show that both substrates occupy the same binding pocket but also indicate some degree of heterogeneity of the bound ligand population, reflecting the promiscuous nature of ligand binding by multidrug efflux pumps. Direct interaction between (13)C-labeled TPP(+) and key residues within the EmrE dimer has been probed by through-space (13)C-(13)C correlation spectroscopy. This was made possible by the use of solid-state NMR enhanced by dynamic nuclear polarization (DNP) through which a 19-fold signal enhancement was achieved. Our data provide clear evidence for the long assumed direct interaction between substrates such as TPP(+) and the essential residue E14 in transmembrane helix 1. Our work also demonstrates the power of DNP-enhanced solid-state NMR at low temperatures for the study for secondary transporters, which are highly challenging for conventional NMR detection.
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Affiliation(s)
- Yean Sin Ong
- Institute of Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance and ‡Institute of Biochemistry, Goethe University Frankfurt , Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
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44
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Ullrich SJ, Glaubitz C. Perspectives in enzymology of membrane proteins by solid-state NMR. Acc Chem Res 2013; 46:2164-71. [PMID: 23745719 DOI: 10.1021/ar4000289] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Membrane proteins catalyze reactions at the cell membrane and facilitate thetransport of molecules or signals across the membrane. Recently researchers have made great progress in understanding the structural biology of membrane proteins, mainly based on X-ray crystallography. In addition, the application of complementary spectroscopic techniques has allowed researchers to develop a functional understanding of these proteins. Solid-state NMR has become an indispensable tool for the structure-function analysis of insoluble proteins and protein complexes. It offers the possibility of investigating membrane proteins directly in their environment, which provides essential information about the intrinsic coupling of protein structure and functional dynamics within the lipid bilayer. However, to date, researchers have hardly explored the enzymology of mem-brane proteins. In this Account, we review the perspectives for investigating membrane-bound enzymes by solid-state NMR. Understanding enzyme mechanisms requires access to kinetic parameters, structural analysis of the catalytic center, knowledge of the 3D structure and methods to follow the structural dynamics of the enzyme during the catalytic cycle. In principle, solid-state NMR can address all of these issues. Researchers can characterize the enzyme kinetics by observing substrate turnover within the membrane or at the membrane interphase in a time-resolved fashion as shown for diacylglycerol kinase. Solid-state NMR has also provided a mechanistic understanding of soluble enzymes including triosephosphate isomerase (TIM) and different metal-binding proteins, which demonstrates a promising perspective also for membrane proteins. The increasing availability of high magnetic fields and the development of new experimental schemes and computational protocols have made it easier to determine 3D structure using solid-state NMR. Dynamic nuclear polarization, a key technique to boost sensitivity of solid-state NMR at low temperatures, can help with the analysis of thermally trapped catalytic intermediates, while methods to improve signal-to-noise per time unit enable the real-time measurement of kinetics of conformational changes during the catalytic cycle.
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Affiliation(s)
- Sandra J. Ullrich
- Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Str. 9, 60438 Frankfurt am Main, Germany
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Str. 9, 60438 Frankfurt am Main, Germany
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45
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Lopez del Amo JM, Schneider D, Loquet A, Lange A, Reif B. Cryogenic solid state NMR studies of fibrils of the Alzheimer's disease amyloid-β peptide: perspectives for DNP. JOURNAL OF BIOMOLECULAR NMR 2013; 56:359-363. [PMID: 23793606 DOI: 10.1007/s10858-013-9755-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 06/12/2013] [Indexed: 06/02/2023]
Abstract
Dynamic Nuclear Polarization solid-state NMR holds the potential to enable a dramatic increase in sensitivity by exploiting the large magnetic moment of the electron. However, applications to biological solids are hampered in uniformly isotopically enriched biomacromolecules due to line broadening which yields a limited spectral resolution at cryogenic temperatures. We show here that high magnetic fields allow to overcome the broadening of resonance lines often experienced at liquid nitrogen temperatures. For a fibril sample of the Alzheimer's disease β-amyloid peptide, we find similar line widths at low temperature and at room temperature. The presented results open new perspectives for structural investigations in the solid-state.
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Affiliation(s)
- Juan-Miguel Lopez del Amo
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit und Umwelt, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
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Markhasin E, Hu J, Su Y, Herzfeld J, Griffin RG. Efficient, balanced, transmission line RF circuits by back propagation of common impedance nodes. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 231:32-8. [PMID: 23567880 PMCID: PMC3739482 DOI: 10.1016/j.jmr.2013.02.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 02/22/2013] [Accepted: 02/28/2013] [Indexed: 05/05/2023]
Abstract
We present a new, efficient strategy for designing fully balanced transmission line RF circuits for solid state NMR probes based on back propagation of common impedance nodes (BPCIN). In this approach, the impedance node phenomenon is the sole means of achieving mutual RF isolation and balance in all RF channels. BPCIN is illustrated using a custom double resonance 3.2 mm MAS probe operating at 500 MHz ((1)H) and 125 MHz ((13)C). When fully optimized, the probe is capable of producing high homogeneity (810°/90° ratios of 86% and 89% for (1)H and (13)C, respectively) and high efficiency (γB1=100 kHz for (1)H and (13)C at 70 W and 180 W of RF input, respectively; up to 360 kHz for (1)H). The probe's performance is illustrated by 2D MAS correlation spectra of microcrystals of the tripeptide N-f-MLF-OH and hydrated amyloid fibrils of the protein PI3-SH3.
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Affiliation(s)
- Evgeny Markhasin
- Francis Bitter Magnet Laboratory, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jianping Hu
- Department of Chemistry, Brandeis University, Waltham, MA 02454, USA
| | - Yongchao Su
- Francis Bitter Magnet Laboratory, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Judith Herzfeld
- Department of Chemistry, Brandeis University, Waltham, MA 02454, USA
| | - Robert G. Griffin
- Francis Bitter Magnet Laboratory, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Vugmeyster L, Ostrovsky D, Lipton AS. Origin of abrupt rise in deuteron NMR longitudinal relaxation times of protein methyl groups below 90 K. J Phys Chem B 2013; 117:6129-37. [PMID: 23627365 DOI: 10.1021/jp4021596] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In order to examine the origin of the abrupt change in the temperature dependence of (2)H NMR longitudinal relaxation times observed previously for methyl groups of L69 in the hydrophobic core of villin headpiece protein at around 90 K (Vugmeyster et al. J. Am. Chem. Soc. 2010, 132, 4038-4039), we extended the measurements to several other methyl groups in the hydrophobic core. We show that, for all methyl groups, relaxation times experience a dramatic jump several orders of magnitude around this temperature. Theoretical modeling supports the conclusion that the origin of the apparent transition in the relaxation times is due to the existence of the distribution of conformers distinguished by their activation energy for methyl three-site hops. It is also crucial to take into account the differential contribution of individual conformers into overall signal intensity. When a particular conformer approaches the regime at which its three-site hop rate constant is on the order of the quadrupolar coupling interaction constant, the intensity of the signal due to this conformer experiences a sharp drop, thus changing the balance of the contributions of different conformers into the overall signal. As a result, the observed apparent transition in the relaxation rates can be explained without the assumption of an underlying transition in the rate constants. This work in combination with earlier results also shows that the model based on the distribution of conformers explains the relaxation behavior in the entire temperature range between 300 and 70 K.
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Affiliation(s)
- Liliya Vugmeyster
- Department of Chemistry, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, Alaska 99508, United States.
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Daviso E, Eddy MT, Andreas LB, Griffin RG, Herzfeld J. Efficient resonance assignment of proteins in MAS NMR by simultaneous intra- and inter-residue 3D correlation spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2013; 55:257-65. [PMID: 23334347 PMCID: PMC3615138 DOI: 10.1007/s10858-013-9707-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Accepted: 01/09/2013] [Indexed: 05/10/2023]
Abstract
Resonance assignment is the first step in NMR structure determination. For magic angle spinning NMR, this is typically achieved with a set of heteronuclear correlation experiments (NCaCX, NCOCX, CONCa) that utilize SPECIFIC-CP (15)N-(13)C transfers. However, the SPECIFIC-CP transfer efficiency is often compromised by molecular dynamics and probe performance. Here we show that one-bond ZF-TEDOR (15)N-(13)C transfers provide simultaneous NCO and NCa correlations with at least as much sensitivity as SPECIFIC-CP for some non-crystalline samples. Furthermore, a 3D ZF-TEDOR-CC experiment provides heteronuclear sidechain correlations and robustness with respect to proton decoupling and radiofrequency power instabilities. We demonstrate transfer efficiencies and connectivities by application of 3D ZF-TEDOR-DARR to a model microcrystalline protein, GB1, and a less ideal system, GvpA in intact gas vesicles.
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Affiliation(s)
- Eugenio Daviso
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, USA, 02454-9110
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 02139
| | - Matthew T. Eddy
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 02139
| | - Loren B. Andreas
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 02139
| | - Robert G. Griffin
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 02139
| | - Judith Herzfeld
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, USA, 02454-9110
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Kobayashi T, Lafon O, Lilly Thankamony AS, Slowing II, Kandel K, Carnevale D, Vitzthum V, Vezin H, Amoureux JP, Bodenhausen G, Pruski M. Analysis of sensitivity enhancement by dynamic nuclear polarization in solid-state NMR: a case study of functionalized mesoporous materials. Phys Chem Chem Phys 2013; 15:5553-62. [DOI: 10.1039/c3cp00039g] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Solid-state NMR spectroscopy proved to be a versatile tool for characterization of structure and dynamics of complex biochemical systems. In particular, magic angle spinning (MAS) solid-state NMR came to maturity for application towards structural elucidation of biological macromolecules. Current challenges in applying solid-state NMR as well as progress achieved recently will be discussed in the following chapter focusing on conceptual aspects important for structural elucidation of proteins.
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Affiliation(s)
- Henrik Müller
- Institute of Physical Biology, Heinrich-Heine-University of Düsseldorf, 40225, Düsseldorf, Germany
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