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Smith JW, Carnevale LN, Das A, Chen Q. Electron videography of a lipid-protein tango. SCIENCE ADVANCES 2024; 10:eadk0217. [PMID: 38630809 PMCID: PMC11023515 DOI: 10.1126/sciadv.adk0217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 03/15/2024] [Indexed: 04/19/2024]
Abstract
Biological phenomena, from enzymatic catalysis to synaptic transmission, originate in the structural transformations of biomolecules and biomolecular assemblies in liquid water. However, directly imaging these nanoscopic dynamics without probes or labels has been a fundamental methodological challenge. Here, we developed an approach for "electron videography"-combining liquid phase electron microscopy with molecular modeling-with which we filmed the nanoscale structural fluctuations of individual, suspended, and unlabeled membrane protein nanodiscs in liquid. Systematic comparisons with biochemical data and simulation indicate the graphene encapsulation involved can afford sufficiently reduced effects of the illuminating electron beam for these observations to yield quantitative fingerprints of nanoscale lipid-protein interactions. Our results suggest that lipid-protein interactions delineate dynamically modified membrane domains across unexpectedly long ranges. Moreover, they contribute to the molecular mechanics of the nanodisc as a whole in a manner specific to the protein within. Overall, this work illustrates an experimental approach to film, quantify, and understand biomolecular dynamics at the nanometer scale.
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Affiliation(s)
- John W. Smith
- Department of Materials Science and Engineering, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
| | - Lauren N. Carnevale
- Department of Biochemistry, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
| | - Aditi Das
- School of Chemistry and Biochemistry, Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Qian Chen
- Department of Materials Science and Engineering, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
- Department of Chemistry, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
- Materials Research Laboratory, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
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2
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Sučec I, Mammeri NE, Dregni AJ, Hong M. Rapid Determination of the Topology of Oligomeric α-Helical Membrane Proteins by Water- and Lipid-Edited Methyl NMR. J Phys Chem B 2023; 127:7518-7530. [PMID: 37606918 PMCID: PMC10893779 DOI: 10.1021/acs.jpcb.3c05295] [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: 08/23/2023]
Abstract
Single-span oligomeric α-helical transmembrane proteins are common in virus ion channels, which are targets of antiviral drugs. Knowledge about the high-resolution structures of these oligomeric α-helical bundles is so far scarce. Structure determination of these membrane proteins by solid-state NMR traditionally requires resolving and assigning protein chemical shifts and measuring many interhelical distances, which are time-consuming. To accelerate experimental structure determination, here we introduce a simple solid-state NMR approach that uses magnetization transfer from water and lipid protons to the protein. By detecting the water- and lipid-transferred intensities of the high-sensitivity methyl 13C signals of Leu, Val, and Ile residues, which are highly enriched in these membrane proteins, we can derive models of the topology of these homo-oligomeric helical bundles. The topology is specified by the positions of amino acid residues in heptad repeats and the orientations of residues relative to the channel pore, lipids, and the helical interface. We demonstrate this water- and lipid-edited methyl NMR approach on the envelope (E) protein of SARS-CoV-2, the causative agent of the COVID-19 pandemic. We show that water-edited and lipid-edited 2D 13C-13C correlation spectra can be measured with sufficient sensitivity. Even without resolving multiple residues of the same type in the NMR spectra, we can obtain the helical bundle topology. We apply these experiments to the structurally unknown E proteins of the MERS coronavirus and the human coronavirus NL63. The resulting structural topologies show interesting differences in the positions of the aromatic residues in these three E proteins, suggesting that these viroporins may have different mechanisms of activation and ion conduction.
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Affiliation(s)
- Iva Sučec
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Nadia El Mammeri
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Aurelio J. Dregni
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
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3
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Tosaka T, Kamiya K. Function Investigations and Applications of Membrane Proteins on Artificial Lipid Membranes. Int J Mol Sci 2023; 24:ijms24087231. [PMID: 37108393 PMCID: PMC10138308 DOI: 10.3390/ijms24087231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
Membrane proteins play an important role in key cellular functions, such as signal transduction, apoptosis, and metabolism. Therefore, structural and functional studies of these proteins are essential in fields such as fundamental biology, medical science, pharmacology, biotechnology, and bioengineering. However, observing the precise elemental reactions and structures of membrane proteins is difficult, despite their functioning through interactions with various biomolecules in living cells. To investigate these properties, methodologies have been developed to study the functions of membrane proteins that have been purified from biological cells. In this paper, we introduce various methods for creating liposomes or lipid vesicles, from conventional to recent approaches, as well as techniques for reconstituting membrane proteins into artificial membranes. We also cover the different types of artificial membranes that can be used to observe the functions of reconstituted membrane proteins, including their structure, number of transmembrane domains, and functional type. Finally, we discuss the reconstitution of membrane proteins using a cell-free synthesis system and the reconstitution and function of multiple membrane proteins.
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Affiliation(s)
- Toshiyuki Tosaka
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Gunma 376-8515, Japan
| | - Koki Kamiya
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Gunma 376-8515, Japan
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4
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Dahmardeh M, Mirzaalian Dastjerdi H, Mazal H, Köstler H, Sandoghdar V. Self-supervised machine learning pushes the sensitivity limit in label-free detection of single proteins below 10 kDa. Nat Methods 2023; 20:442-447. [PMID: 36849549 PMCID: PMC9998267 DOI: 10.1038/s41592-023-01778-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 01/06/2023] [Indexed: 03/01/2023]
Abstract
Interferometric scattering (iSCAT) microscopy is a label-free optical method capable of detecting single proteins, localizing their binding positions with nanometer precision, and measuring their mass. In the ideal case, iSCAT is limited by shot noise such that collection of more photons should extend its detection sensitivity to biomolecules of arbitrarily low mass. However, a number of technical noise sources combined with speckle-like background fluctuations have restricted the detection limit in iSCAT. Here, we show that an unsupervised machine learning isolation forest algorithm for anomaly detection pushes the mass sensitivity limit by a factor of 4 to below 10 kDa. We implement this scheme both with a user-defined feature matrix and a self-supervised FastDVDNet and validate our results with correlative fluorescence images recorded in total internal reflection mode. Our work opens the door to optical investigations of small traces of biomolecules and disease markers such as α-synuclein, chemokines and cytokines.
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Affiliation(s)
- Mahyar Dahmardeh
- Max Planck Institute for the Science of Light, Erlangen, Germany.,Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Houman Mirzaalian Dastjerdi
- Max Planck Institute for the Science of Light, Erlangen, Germany.,Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany.,Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Hisham Mazal
- Max Planck Institute for the Science of Light, Erlangen, Germany.,Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Harald Köstler
- Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Erlangen National High Performance Computing Center (NHR@FAU), Erlangen, Germany
| | - Vahid Sandoghdar
- Max Planck Institute for the Science of Light, Erlangen, Germany. .,Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany. .,Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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5
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Umegawa Y, Kawatake S, Murata M, Matsuoka S. Combined effect of the head groups and alkyl chains of archaea lipids when interacting with bacteriorhodopsin. Biophys Chem 2023; 294:106959. [PMID: 36709544 DOI: 10.1016/j.bpc.2023.106959] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023]
Abstract
Bacteriorhodopsin (bR), a transmembrane protein with seven α-helices, is highly expressed in the purple membrane (PM) of archaea such as Halobacterium salinarum. It is well known that bR forms two-dimensional crystals with acidic lipids such as phosphatidylglycerol phosphate methyl ester (PGP-Me)-a major component of PM lipids bearing unique chemical structures-methyl-branched alkyl chains, ether linkages, and divalent anionic head groups with two phosphodiester groups. Therefore, we aimed to determine which functional groups of PGP-Me are essential for the boundary lipids of bR and how these functionalities interact with bR. To this end, we compared various well-known phospholipids (PLs) that carry one of the structural features of PGP-Me, and evaluated the affinity of PLs to bR using the centerband-only analysis of rotor-unsynchronized spin echo (COARSE) method in solid-state NMR measurements and thermal shift assays. The results clearly showed that the branched methyl groups of alkyl chains and double negative charges in the head groups are important for PL interactions with bR. We then examined the effect of phospholipids on the monomer-trimer exchange of bR using circular dichroism (CD) spectra. The results indicated that the divalent negative charge in a head group stabilizes the trimer structure, while the branched methyl chains significantly enhance the PLs' affinity for bR, thus dispersing bR trimers in the PM even at high concentrations. Finally, we investigated the effects of PL on the proton-pumping activity of bR based on the decay rate constant of the M intermediate of a bR photocycle. The findings showed that bR activities decreased to 20% in 1,2-dimyristoyl-sn-glycero-3-phosphate (DMPA), and in 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) bilayers as compared to that in PM. Meanwhile, 1,2-Diphytanoyl-sn-glycero-3-phosphate (DPhPA) bilayers bearing both negative charges and branched methyl groups preserved over 80% of the activity. These results strongly suggest that the head groups and alkyl chains of phospholipids are essential for boundary lipids and greatly influence the biological function of bR.
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Affiliation(s)
- Yuichi Umegawa
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
| | - Satoshi Kawatake
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Michio Murata
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Shigeru Matsuoka
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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6
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Cheung E, Xia Y, Caporini MA, Gilmore JL. Tools shaping drug discovery and development. BIOPHYSICS REVIEWS 2022; 3:031301. [PMID: 38505278 PMCID: PMC10903431 DOI: 10.1063/5.0087583] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 06/21/2022] [Indexed: 03/21/2024]
Abstract
Spectroscopic, scattering, and imaging methods play an important role in advancing the study of pharmaceutical and biopharmaceutical therapies. The tools more familiar to scientists within industry and beyond, such as nuclear magnetic resonance and fluorescence spectroscopy, serve two functions: as simple high-throughput techniques for identification and purity analysis, and as potential tools for measuring dynamics and structures of complex biological systems, from proteins and nucleic acids to membranes and nanoparticle delivery systems. With the expansion of commercial small-angle x-ray scattering instruments into the laboratory setting and the accessibility of industrial researchers to small-angle neutron scattering facilities, scattering methods are now used more frequently in the industrial research setting, and probe-less time-resolved small-angle scattering experiments are now able to be conducted to truly probe the mechanism of reactions and the location of individual components in complex model or biological systems. The availability of atomic force microscopes in the past several decades enables measurements that are, in some ways, complementary to the spectroscopic techniques, and wholly orthogonal in others, such as those related to nanomechanics. As therapies have advanced from small molecules to protein biologics and now messenger RNA vaccines, the depth of biophysical knowledge must continue to serve in drug discovery and development to ensure quality of the drug, and the characterization toolbox must be opened up to adapt traditional spectroscopic methods and adopt new techniques for unraveling the complexities of the new modalities. The overview of the biophysical methods in this review is meant to showcase the uses of multiple techniques for different modalities and present recent applications for tackling particularly challenging situations in drug development that can be solved with the aid of fluorescence spectroscopy, nuclear magnetic resonance spectroscopy, atomic force microscopy, and small-angle scattering.
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Affiliation(s)
- Eugene Cheung
- Moderna, 200 Technology Square, Cambridge, Massachusetts 02139, USA
| | - Yan Xia
- Moderna, 200 Technology Square, Cambridge, Massachusetts 02139, USA
| | - Marc A. Caporini
- Moderna, 200 Technology Square, Cambridge, Massachusetts 02139, USA
| | - Jamie L. Gilmore
- Moderna, 200 Technology Square, Cambridge, Massachusetts 02139, USA
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7
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Cisse A, Matsuo T, Plazanet M, Natali F, Koza MM, Ollivier J, Bicout DJ, Peters J. The dynamical Matryoshka model: 2. Modeling of local lipid dynamics at the sub-nanosecond timescale in phospholipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183950. [PMID: 35525301 DOI: 10.1016/j.bbamem.2022.183950] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 04/06/2022] [Accepted: 04/25/2022] [Indexed: 12/12/2022]
Abstract
Biological membranes are generally formed by lipids and proteins. Often, the membrane properties are studied through model membranes formed by phospholipids only. They are molecules composed by a hydrophilic head group and hydrophobic tails, which can present a panoply of various motions, including small localized movements of a few atoms up to the diffusion of the whole lipid or collective motions of many of them. In the past, efforts were made to measure these motions experimentally by incoherent neutron scattering and to quantify them, but with upcoming modern neutron sources and instruments, such models can now be improved. In the present work, we expose a quantitative and exhaustive study of lipid dynamics on DMPC and DMPG membranes, using the Matryoshka model recently developed by our group. The model is confronted here to experimental data collected on two different membrane samples, at three temperatures and two instruments. Despite such complexity, the model describes reliably the data and permits to extract a series of parameters. The results compare also very well to other values found in the literature.
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Affiliation(s)
- Aline Cisse
- Univ. Grenoble Alpes, CNRS, LiPhy, 38000 Grenoble, France; Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, 7, France
| | - Tatsuhito Matsuo
- Univ. Grenoble Alpes, CNRS, LiPhy, 38000 Grenoble, France; Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, 7, France; Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 2-4 Shirakata, Tokai, Ibaraki 319-1106, Japan
| | - Marie Plazanet
- Univ. Grenoble Alpes, CNRS, LiPhy, 38000 Grenoble, France
| | - Francesca Natali
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, 7, France; CNR-IOM and INSIDE@ILL, c/o OGG, 38042 Grenoble Cedex 9, France
| | - Michael Marek Koza
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, 7, France
| | - Jacques Ollivier
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, 7, France
| | - Dominique J Bicout
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, 7, France; Univ. Grenoble Alpes, CNRS, Grenoble INP, VetAgro Sup, TIMC, 38000 Grenoble, France
| | - Judith Peters
- Univ. Grenoble Alpes, CNRS, LiPhy, 38000 Grenoble, France; Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, 7, France; Institut Universitaire de France, France.
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8
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Protein Lipidation Types: Current Strategies for Enrichment and Characterization. Int J Mol Sci 2022; 23:ijms23042365. [PMID: 35216483 PMCID: PMC8880637 DOI: 10.3390/ijms23042365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 02/18/2022] [Accepted: 02/18/2022] [Indexed: 12/04/2022] Open
Abstract
Post-translational modifications regulate diverse activities of a colossal number of proteins. For example, various types of lipids can be covalently linked to proteins enzymatically or non-enzymatically. Protein lipidation is perhaps not as extensively studied as protein phosphorylation, ubiquitination, or glycosylation although it is no less significant than these modifications. Evidence suggests that proteins can be attached by at least seven types of lipids, including fatty acids, lipoic acids, isoprenoids, sterols, phospholipids, glycosylphosphatidylinositol anchors, and lipid-derived electrophiles. In this review, we summarize types of protein lipidation and methods used for their detection, with an emphasis on the conjugation of proteins with polyunsaturated fatty acids (PUFAs). We discuss possible reasons for the scarcity of reports on PUFA-modified proteins, limitations in current methodology, and potential approaches in detecting PUFA modifications.
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9
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Dependence of Protein Structure on Environment: FOD Model Applied to Membrane Proteins. MEMBRANES 2021; 12:membranes12010050. [PMID: 35054576 PMCID: PMC8778870 DOI: 10.3390/membranes12010050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/13/2021] [Accepted: 12/28/2021] [Indexed: 11/17/2022]
Abstract
The natural environment of proteins is the polar aquatic environment and the hydrophobic (amphipathic) environment of the membrane. The fuzzy oil drop model (FOD) used to characterize water-soluble proteins, as well as its modified version FOD-M, enables a mathematical description of the presence and influence of diverse environments on protein structure. The present work characterized the structures of membrane proteins, including those that act as channels, and a water-soluble protein for contrast. The purpose of the analysis was to verify the possibility that an external force field can be used in the simulation of the protein-folding process, taking into account the diverse nature of the environment that guarantees a structure showing biological activity.
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10
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Tang J, Chu Y, Li S, Xu J, Xiong W, Wang Q, Deng F. Breathing Effect via Solvent Inclusions on the Linker Rotational Dynamics of Functionalized MIL-53. Chemistry 2021; 27:14711-14720. [PMID: 34357658 DOI: 10.1002/chem.202102419] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Indexed: 12/24/2022]
Abstract
The breathing effects of functionalized MIL-53-X (X=H, CH3 , NH2 , OH, and NO2 ) induced by the inclusions of water, methanol, acetone, and N,N-dimethylformamide solvents were comprehensively investigated by solid-state NMR spectroscopy. 2D homo-nuclear correlation NMR provided direct experimental evidence for the host-guest interaction between the guest solvents and the MOF frameworks. The variations of the 1 H and 13 C NMR chemical shifts in functionalized MIL-53 from the narrow pore phase transitions to large pore forms due to solvent inclusions were clearly identified. The influence of functionalized linkers and their host-guest interactions with the confined solvents on the rotational dynamics of the linkers was examined by separated-local-field MAS NMR experiments in conjunction with DFT theoretical calculations. It is found that the linker rotational dynamics of functionalized MIL-53 in narrow pore form is closely related to the computational rotational energy barrier. The BDC-NO2 linker of activated MIL-53-NO2 undergoes relatively faster rotation, whereas the BDC-NH2 and BDC-OH linkers of activated MIL-53-NH2 and MIL-53-OH exhibit relatively slower rotation. The host-guest interactions between confined solvents and MIL-53-NO2 , MIL-53-CH3 would significantly induce an increase of the order parameters of unsubstituted carbon and reduce the rotational frequency of linkers. This study provides a spectroscopic approach for the investigation of linker rotation in functionalized MOFs at natural abundance with solvents inclusions.
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Affiliation(s)
- Jing Tang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071, Wuhan, P. R. China.,University of Chinese Academy of Sciences, 100049, Beijing, P. R. China
| | - Yueying Chu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071, Wuhan, P. R. China
| | - Shenhui Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071, Wuhan, P. R. China
| | - Jun Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071, Wuhan, P. R. China
| | - Wenpeng Xiong
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071, Wuhan, P. R. China.,University of Chinese Academy of Sciences, 100049, Beijing, P. R. China
| | - Qiang Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071, Wuhan, P. R. China
| | - Feng Deng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071, Wuhan, P. R. China
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11
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Abstract
Membrane proteins (MPs) play essential roles in numerous cellular processes. Because around 70% of the currently marketed drugs target MPs, a detailed understanding of their structure, binding properties, and functional dynamics in a physiologically relevant environment is crucial for a more detailed understanding of this important protein class. We here summarize the benefits of using lipid nanodiscs for NMR structural investigations and provide a detailed overview of the currently used lipid nanodisc systems as well as their applications in solution-state NMR. Despite the increasing use of other structural methods for the structure determination of MPs in lipid nanodiscs, solution NMR turns out to be a versatile tool to probe a wide range of MP features, ranging from the structure determination of small to medium-sized MPs to probing ligand and partner protein binding as well as functionally relevant dynamical signatures in a lipid nanodisc setting. We will expand on these topics by discussing recent NMR studies with lipid nanodiscs and work out a key workflow for optimizing the nanodisc incorporation of an MP for subsequent NMR investigations. With this, we hope to provide a comprehensive background to enable an informed assessment of the applicability of lipid nanodiscs for NMR studies of a particular MP of interest.
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Affiliation(s)
- Umut Günsel
- Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Strasse 2, 85748 Garching, Germany
| | - Franz Hagn
- Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Strasse 2, 85748 Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
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12
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Volkov VI, Chernyak AV, Avilova IA, Slesarenko NA, Melnikova DL, Skirda VD. Molecular and Ionic Diffusion in Ion Exchange Membranes and Biological Systems (Cells and Proteins) Studied by NMR. MEMBRANES 2021; 11:385. [PMID: 34074055 PMCID: PMC8225114 DOI: 10.3390/membranes11060385] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/30/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022]
Abstract
The results of NMR, and especially pulsed field gradient NMR (PFG NMR) investigations, are summarized. Pulsed field gradient NMR technique makes it possible to investigate directly the partial self-diffusion processes in spatial scales from tenth micron to millimeters. Modern NMR spectrometer diffusive units enable to measure self-diffusion coefficients from 10-13 m2/s to 10-8 m2/s in different materials on 1 H, 2 H, 7 Li, 13 C, 19 F, 23 Na, 31 P, 133 Cs nuclei. PFG NMR became the method of choice for reveals of transport mechanism in polymeric electrolytes for lithium batteries and fuel cells. Second wide field of application this technique is the exchange processes and lateral diffusion in biological cells as well as molecular association of proteins. In this case a permeability, cell size, and associate lifetime could be estimated. The authors have presented the review of their research carried out in Karpov Institute of Physical Chemistry, Moscow, Russia; Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia; Kazan Federal University, Kazan, Russia; Korea University, Seoul, South Korea; Yokohama National University, Yokohama, Japan. The results of water molecule and Li+, Na+, Cs+ cation self-diffusion in Nafion membranes and membranes based on sulfonated polystyrene, water (and water soluble) fullerene derivative permeability in RBC, casein molecule association have being discussed.
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Affiliation(s)
- Vitaliy I. Volkov
- Institute of Problems of Chemical Physics RAS, 142432 Chernogolovka, Russia; (A.V.C.); (I.A.A.); (N.A.S.)
- Scientific Center in Chernogolovka RAS, 142432 Chernogolovka, Russia
| | - Alexander V. Chernyak
- Institute of Problems of Chemical Physics RAS, 142432 Chernogolovka, Russia; (A.V.C.); (I.A.A.); (N.A.S.)
- Scientific Center in Chernogolovka RAS, 142432 Chernogolovka, Russia
| | - Irina A. Avilova
- Institute of Problems of Chemical Physics RAS, 142432 Chernogolovka, Russia; (A.V.C.); (I.A.A.); (N.A.S.)
| | - Nikita A. Slesarenko
- Institute of Problems of Chemical Physics RAS, 142432 Chernogolovka, Russia; (A.V.C.); (I.A.A.); (N.A.S.)
| | - Daria L. Melnikova
- Institute of Physics, KazanFederal University, 420008 Kazan, Russia; (D.L.M.); (V.D.S.)
| | - Vladimir D. Skirda
- Institute of Physics, KazanFederal University, 420008 Kazan, Russia; (D.L.M.); (V.D.S.)
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13
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Pohorille A, Wilson MA. Computational Electrophysiology from a Single Molecular Dynamics Simulation and the Electrodiffusion Model. J Phys Chem B 2021; 125:3132-3144. [DOI: 10.1021/acs.jpcb.0c10737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrew Pohorille
- Exobiology Branch, MS239-4, NASA Ames Research Center, Moffett Field, California 94035, United States
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94132, United States
| | - Michael A. Wilson
- Exobiology Branch, MS239-4, NASA Ames Research Center, Moffett Field, California 94035, United States
- SETI Institute, 189 Bernardo Avenue, Suite 200, Mountain View, California 94043, United States
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14
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Narasimhan S, Pinto C, Lucini Paioni A, van der Zwan J, Folkers GE, Baldus M. Characterizing proteins in a native bacterial environment using solid-state NMR spectroscopy. Nat Protoc 2021; 16:893-918. [PMID: 33442051 DOI: 10.1038/s41596-020-00439-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/09/2020] [Indexed: 01/29/2023]
Abstract
For a long time, solid-state nuclear magnetic resonance (ssNMR) has been employed to study complex biomolecular systems at the detailed chemical, structural, or dynamic level. Recent progress in high-resolution and high-sensitivity ssNMR, in combination with innovative sample preparation and labeling schemes, offers novel opportunities to study proteins in their native setting irrespective of the molecular tumbling rate. This protocol describes biochemical preparation schemes to obtain cellular samples of both soluble as well as insoluble or membrane-associated proteins in bacteria. To this end, the protocol is suitable for studying a protein of interest in both whole cells and in cell envelope or isolated membrane preparations. In the first stage of the procedure, an appropriate strain of Escherichia coli (DE3) is transformed with a plasmid of interest harboring the protein of interest under the control of an inducible T7 promoter. Next, the cells are adapted to grow in minimal (M9) medium. Before the growth enters stationary phase, protein expression is induced, and shortly thereafter, the native E. coli RNA polymerase is inhibited using rifampicin for targeted labeling of the protein of interest. The cells are harvested after expression and prepared for ssNMR rotor filling. In addition to conventional 13C/15N-detected ssNMR, we also outline how these preparations can be readily subjected to multidimensional ssNMR experiments using dynamic nuclear polarization (DNP) or proton (1H) detection schemes. We estimate that the entire preparative procedure until NMR experiments can be started takes 3-5 days.
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Affiliation(s)
- Siddarth Narasimhan
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands.,Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Cecilia Pinto
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands.,Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Alessandra Lucini Paioni
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands
| | - Johan van der Zwan
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands
| | - Gert E Folkers
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands.
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15
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Abstract
Molecular dynamics simulations of membrane proteins have grown dramatically in the last 20 years. Running these simulations first requires embedding the protein's three-dimensional structure in a lipid bilayer of a suitable composition, one that resembles its native environment. This step is far from trivial, especially for modeling heterogeneous mixtures of lipids. CHARMM-GUI, a webserver for simulation system preparation greatly simplifies this step, allowing for the construction of complex heterogeneous and/or asymmetric membranes. Here, we demonstrate how to use CHARMM-GUI to build the membrane for the outer-membrane protein BamA.
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16
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Rovó P. Recent advances in solid-state relaxation dispersion techniques. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2020; 108:101665. [PMID: 32574905 DOI: 10.1016/j.ssnmr.2020.101665] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/11/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
This review describes two rotating-frame (R1ρ) relaxation dispersion methods, namely the Bloch-McConnell Relaxation Dispersion and the Near-rotary Resonance Relaxation Dispersion, which enable the study of microsecond time-scale conformational fluctuations in the solid state using magic-angle-spinning nuclear magnetic resonance spectroscopy. The goal is to provide the reader with key ideas, experimental descriptions, and practical considerations associated with R1ρ measurements that are needed for analyzing relaxation dispersion and quantifying conformational exchange. While the focus is on protein motion, many presented concepts can be equally well adapted to study the microsecond time-scale dynamics of other bio- (e.g. lipids, polysaccharides, nucleic acids), organic (e.g. pharmaceutical compounds), or inorganic molecules (e.g., metal organic frameworks). This article summarizes the essential contributions made by recent theoretical and experimental solid-state NMR studies to our understanding of protein motion. Here we discuss recent advances in fast MAS applications that enable the observation and atomic level characterization of sparsely populated conformational states which are otherwise inaccessible for other experimental methods. Such high-energy states are often associated with protein functions such as molecular recognition, ligand binding, or enzymatic catalysis, as well as with disease-related properties such as misfolding and amyloid formation.
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Affiliation(s)
- Petra Rovó
- Department of Chemistry, Ludwig Maximilian University Munich, Butenandtstr. 5-13, 81377, Munich, Germany; Center for NanoScience (CeNS), Schellingstr. 4, 80799, Munich, Germany.
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17
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Hoffmann J, Ruta J, Shi C, Hendriks K, Chevelkov V, Franks WT, Oschkinat H, Giller K, Becker S, Lange A. Protein resonance assignment by BSH-CP-based 3D solid-state NMR experiments: A practical guide. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:445-465. [PMID: 31691361 DOI: 10.1002/mrc.4945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 07/05/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
Solid-state NMR (ssNMR) spectroscopy has evolved into a powerful method to obtain structural information and to study the dynamics of proteins at atomic resolution and under physiological conditions. The method is especially well suited to investigate insoluble and noncrystalline proteins that cannot be investigated easily by X-ray crystallography or solution NMR. To allow for detailed analysis of ssNMR data, the assignment of resonances to the protein atoms is essential. For this purpose, a set of three-dimensional (3D) spectra needs to be acquired. Band-selective homo-nuclear cross-polarization (BSH-CP) is an effective method for magnetization transfer between carbonyl carbon (CO) and alpha carbon (CA) atoms, which is an important transfer step in multidimensional ssNMR experiments. This tutorial describes the detailed procedure for the chemical shift assignment of the backbone atoms of 13 C-15 N-labeled proteins by BSH-CP-based 13 C-detected ssNMR experiments. A set of six 3D experiments is used for unambiguous assignment of the protein backbone as well as certain side-chain resonances. The tutorial especially addresses scientists with little experience in the field of ssNMR and provides all the necessary information for protein assignment in an efficient, time-saving approach.
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Affiliation(s)
- Jutta Hoffmann
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Julia Ruta
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Chaowei Shi
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Kitty Hendriks
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Veniamin Chevelkov
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - W Trent Franks
- Department of NMR-supported Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Hartmut Oschkinat
- Department of NMR-supported Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Karin Giller
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stefan Becker
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
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18
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Munro R, de Vlugt J, Ladizhansky V, Brown LS. Improved Protocol for the Production of the Low-Expression Eukaryotic Membrane Protein Human Aquaporin 2 in Pichia pastoris for Solid-State NMR. Biomolecules 2020; 10:biom10030434. [PMID: 32168846 PMCID: PMC7175339 DOI: 10.3390/biom10030434] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 12/16/2022] Open
Abstract
Solid-state nuclear magnetic resonance (SSNMR) is a powerful biophysical technique for studies of membrane proteins; it requires the incorporation of isotopic labels into the sample. This is usually accomplished through over-expression of the protein of interest in a prokaryotic or eukaryotic host in minimal media, wherein all (or some) carbon and nitrogen sources are isotopically labeled. In order to obtain multi-dimensional NMR spectra with adequate signal-to-noise ratios suitable for in-depth analysis, one requires high yields of homogeneously structured protein. Some membrane proteins, such as human aquaporin 2 (hAQP2), exhibit poor expression, which can make producing a sample for SSNMR in an economic fashion extremely difficult, as growth in minimal media adds additional strain on expression hosts. We have developed an optimized growth protocol for eukaryotic membrane proteins in the methylotrophic yeast Pichia pastoris. Our new growth protocol uses the combination of sorbitol supplementation, higher cell density, and low temperature induction (LT-SEVIN), which increases the yield of full-length, isotopically labeled hAQP2 ten-fold. Combining mass spectrometry and SSNMR, we were able to determine the nature and the extent of post-translational modifications of the protein. The resultant protein can be functionally reconstituted into lipids and yields excellent resolution and spectral coverage when analyzed by two-dimensional SSNMR spectroscopy.
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19
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Rose-Sperling D, Tran MA, Lauth LM, Goretzki B, Hellmich UA. 19F NMR as a versatile tool to study membrane protein structure and dynamics. Biol Chem 2020; 400:1277-1288. [PMID: 31004560 DOI: 10.1515/hsz-2018-0473] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/17/2019] [Indexed: 12/25/2022]
Abstract
To elucidate the structures and dynamics of membrane proteins, highly advanced biophysical methods have been developed that often require significant resources, both for sample preparation and experimental analyses. For very complex systems, such as membrane transporters, ion channels or G-protein coupled receptors (GPCRs), the incorporation of a single reporter at a select site can significantly simplify the observables and the measurement/analysis requirements. Here we present examples using 19F nuclear magnetic resonance (NMR) spectroscopy as a powerful, yet relatively straightforward tool to study (membrane) protein structure, dynamics and ligand interactions. We summarize methods to incorporate 19F labels into proteins and discuss the type of information that can be readily obtained for membrane proteins already from relatively simple NMR spectra with a focus on GPCRs as the membrane protein family most extensively studied by this technique. In the future, these approaches may be of particular interest also for many proteins that undergo complex functional dynamics and/or contain unstructured regions and thus are not amenable to X-ray crystallography or cryo electron microscopy (cryoEM) studies.
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Affiliation(s)
- Dania Rose-Sperling
- Institute for Pharmacy and Biochemistry, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany.,Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Mai Anh Tran
- Institute for Pharmacy and Biochemistry, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany.,Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Luca M Lauth
- Institute for Pharmacy and Biochemistry, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany
| | - Benedikt Goretzki
- Institute for Pharmacy and Biochemistry, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany.,Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany
| | - Ute A Hellmich
- Institute for Pharmacy and Biochemistry, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany.,Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue Str. 9, D-60438 Frankfurt, Germany
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20
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Mandal S, Sigurdsson ST. Water-soluble BDPA radicals with improved persistence. Chem Commun (Camb) 2020; 56:13121-13124. [DOI: 10.1039/d0cc04920d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
1,3-Bis(diphenylene)-2-phenylallyl (BDPA) radicals are promising polarizing agents for dynamic nuclear polarization (DNP) NMR spectroscopy. BDPAs containing tetraalkyl/aryl-ammonium groups have increased persistence and solubility in polar solvents.
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Affiliation(s)
- Sucharita Mandal
- University of Iceland
- Department of Chemistry
- Science Institute
- Reykjavik 107
- Iceland
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21
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Yu NT, Zhang QY. A transmembrane domain of Andrias davidianus ranavirus 13R is crucial for co-localization to endoplasmic reticulum and viromatrix. 3 Biotech 2019; 9:433. [PMID: 31696038 DOI: 10.1007/s13205-019-1961-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 10/18/2019] [Indexed: 12/19/2022] Open
Abstract
13R, a core gene of Andrias davidianus ranavirus (ADRV), encoded a protein containing a transmembrane domain (TMD) and a restriction endonuclease-like domain. However, the characterization and function of 13R and the protein it encodes remain unclear. In this study, Chinese giant salamander thymus cell (GSTC) was used to investigate the function of 13R. The results showed that the 13R transcripts were detected first at 8 h post-infection (hpi) by RT-PCR and the protein was detected first at 24 hpi by western blot, but the transcription was inhibited by cycloheximide and cytosine arabinofuranoside, indicating that 13R is a viral late gene. Subcellular localization showed that the 13R was co-localized with endoplasmic reticulum (ER) in the cytoplasm, while 13R deleting TMD (13RΔTM) was distributed in cytoplasm and nucleus. During ADRV infection, 13R was observed first in the cytoplasm and nucleus, and later aggregated into the viromatrix, whereas 13RΔTM remain dispersed in cytoplasm and nucleus. Western blot analysis suggested that 13R was a viral non-structural protein and its overexpression did not affect the viral titer in GSTC. All these indicated that the TMD of 13R is crucial for the co-localization into the ER and the viromatrix.
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Affiliation(s)
- Nai-Tong Yu
- 1State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
- 2University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Qi-Ya Zhang
- 1State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
- 2University of Chinese Academy of Sciences, Beijing, 100049 China
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22
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Wang S, Gopinath T, Veglia G. Improving the quality of oriented membrane protein spectra using heat-compensated separated local field experiments. JOURNAL OF BIOMOLECULAR NMR 2019; 73:617-624. [PMID: 31463642 PMCID: PMC6861693 DOI: 10.1007/s10858-019-00273-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/21/2019] [Indexed: 05/03/2023]
Abstract
Oriented sample solid-state NMR (OS-ssNMR) spectroscopy is a powerful technique to determine the topology of membrane proteins in oriented lipid bilayers. Separated local field (SLF) experiments are central to this technique as they provide first-order orientational restraints, i.e., dipolar couplings and anisotropic chemical shifts. Despite the use of low-E (or E-free) probes, the heat generated during the execution of 2D and 3D SLF pulse sequences causes sizeable line-shape distortions. Here, we propose a new heat-compensated SE-SAMPI4 (hcSE-SAMPI4) pulse sequence that holds the temperature constant for the duration of the experiment. This modification of the SE-SAMPI4 results in sharper and more intense resonances without line-shape distortions. The spectral improvements are even more apparent when paramagnetic relaxation agents are used to speed up data collection. We tested the hcSE-SAMPI4 pulse sequence on a single-span membrane protein, sarcolipin (SLN), reconstituted in magnetically aligned lipid bicelles. In addition to eliminating peak distortions, the hcSE-SAMPI4 experiment increased the average signal-to-noise ratio by 20% with respect to the original SE-SAMPI4.
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Affiliation(s)
- Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - T Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
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23
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Klöpfer K, Hagn F. Beyond detergent micelles: The advantages and applications of non-micellar and lipid-based membrane mimetics for solution-state NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:271-283. [PMID: 31779883 DOI: 10.1016/j.pnmrs.2019.08.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/20/2019] [Accepted: 08/22/2019] [Indexed: 06/10/2023]
Abstract
Membrane proteins are important players in signal transduction and the exchange of metabolites within or between cells. Thus, this protein class is the target of around 60 % of currently marketed drugs, emphasizing their essential biological role. Besides functional assays, structural and dynamical investigations on this protein class are crucial to fully understanding their functionality. Even though X-ray crystallography and electron microscopy are the main methods to determine structures of membrane proteins and their complexes, NMR spectroscopy can contribute essential information on systems that (a) do not crystallize and (b) are too small for EM. Furthermore, NMR is a versatile tool for monitoring functional dynamics of biomolecules at various time scales. A crucial aspect of such studies is the use of a membrane mimetic that resembles a native environment and thus enables the extraction of functional insights. In recent decades, the membrane protein NMR community has moved from rather harsh detergents to membrane systems having more native-like properties. In particular, most recently phospholipid nanodiscs have been developed and optimized mainly for solution-state NMR but are now also being used for solid-state NMR spectroscopy. Nanodiscs consist of a patch of a planar lipid bilayer that is encircled by different (bio-)polymers to form particles of defined and tunable size. In this review, we provide an overview of available membrane mimetics, including nanodiscs, amphipols and bicelles, that are suitable for high-resolution NMR spectroscopy and describe how these advanced membrane mimetics can facilitate NMR studies on the structure and dynamics of membrane proteins. Since the stability of membrane proteins depends critically on the chosen membrane mimetic, we emphasize the importance of a suitable system that is not necessarily developed for solution-state NMR applications and hence requires optimization for each membrane protein. However, lipid-based membrane mimetics offer the possibility of performing NMR experiments at elevated temperatures and studying ligand and partner protein complexes as well as their functional dynamics in a realistic membrane environment. In order to be able to make an informed decision during the selection of a suitable membrane system, we provide a detailed overview of the available options for various membrane protein classes and thereby facilitate this often-difficult selection process for a broad range of desired NMR applications.
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Affiliation(s)
- Kai Klöpfer
- Bavarian NMR Center at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85747 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Franz Hagn
- Bavarian NMR Center at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85747 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
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24
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Elkins MR, Hong M. Elucidating ligand-bound structures of membrane proteins using solid-state NMR spectroscopy. Curr Opin Struct Biol 2019; 57:103-109. [PMID: 30903830 PMCID: PMC6697555 DOI: 10.1016/j.sbi.2019.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/05/2019] [Accepted: 02/08/2019] [Indexed: 01/08/2023]
Abstract
Magic-angle-spinning (MAS) solid-state NMR spectroscopy is a versatile technique to elucidate functionally important protein-ligand interactions in lipid membranes. Here, we review recent solid-state NMR studies of membrane protein interactions with cholesterol, lipids, transported substrates, and peptide ligands. These studies are conducted in synthetic or native lipid bilayers to provide an accurate environment for ligand binding. The solid-state NMR approaches include multinuclear detection to gain comprehensive structural information, distance measurements to locate ligand-binding sites, and dynamic nuclear polarization and 1H detection to enhance spectral sensitivity. These studies provide novel insights into the mechanisms of virus budding, virus entry into cells, transmembrane signaling, substrate transport, antibacterial action, and many other biological processes.
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Affiliation(s)
- Matthew R Elkins
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States.
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25
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Gopinath T, Wang S, Lee J, Aihara H, Veglia G. Hybridization of TEDOR and NCX MAS solid-state NMR experiments for simultaneous acquisition of heteronuclear correlation spectra and distance measurements. JOURNAL OF BIOMOLECULAR NMR 2019; 73:141-153. [PMID: 30805819 PMCID: PMC6526076 DOI: 10.1007/s10858-019-00237-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 02/12/2019] [Indexed: 05/05/2023]
Abstract
Magic angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy is a major technique for the characterization of the structural dynamics of biopolymers at atomic resolution. However, the intrinsic low sensitivity of this technique poses significant limitations to its routine application in structural biology. Here we achieve substantial savings in experimental time using a new subclass of Polarization Optimized Experiments (POEs) that concatenate TEDOR and SPECIFIC-CP transfers into a single pulse sequence. Specifically, we designed new 2D and 3D experiments (2D TEDOR-NCX, 3D TEDOR-NCOCX, and 3D TEDOR-NCACX) to obtain distance measurements and heteronuclear chemical shift correlations for resonance assignments using only one experiment. We successfully tested these experiments on N-Acetyl-Val-Leu dipeptide, microcrystalline U-13C,15N ubiquitin, and single- and multi-span membrane proteins reconstituted in lipid membranes. These pulse sequences can be implemented on any ssNMR spectrometer equipped with standard solid-state hardware using only one receiver. Since these new POEs speed up data acquisition considerably, we anticipate their broad application to fibrillar, microcrystalline, and membrane-bound proteins.
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Affiliation(s)
- T Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA
| | - Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA
| | - John Lee
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA.
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
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26
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Pinto C, Mance D, Julien M, Daniels M, Weingarth M, Baldus M. Studying assembly of the BAM complex in native membranes by cellular solid-state NMR spectroscopy. J Struct Biol 2019; 206:1-11. [DOI: 10.1016/j.jsb.2017.11.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/24/2017] [Accepted: 11/28/2017] [Indexed: 12/31/2022]
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27
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Bolla JR, Agasid MT, Mehmood S, Robinson CV. Membrane Protein-Lipid Interactions Probed Using Mass Spectrometry. Annu Rev Biochem 2019; 88:85-111. [PMID: 30901263 DOI: 10.1146/annurev-biochem-013118-111508] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Membrane proteins that exist in lipid bilayers are not isolated molecular entities. The lipid molecules that surround them play crucial roles in maintaining their full structural and functional integrity. Research directed at investigating these critical lipid-protein interactions is developing rapidly. Advancements in both instrumentation and software, as well as in key biophysical and biochemical techniques, are accelerating the field. In this review, we provide a brief outline of structural techniques used to probe protein-lipid interactions and focus on the molecular aspects of these interactions obtained from native mass spectrometry (native MS). We highlight examples in which lipids have been shown to modulate membrane protein structure and show how native MS has emerged as a complementary technique to X-ray crystallography and cryo-electron microscopy. We conclude with a short perspective on future developments that aim to better understand protein-lipid interactions in the native environment.
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Affiliation(s)
- Jani Reddy Bolla
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Mark T Agasid
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Shahid Mehmood
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
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28
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Gupta S. Using X-ray Footprinting and Mass Spectrometry to Study the Structure and Function of Membrane Proteins. Protein Pept Lett 2019; 26:44-54. [PMID: 30484402 DOI: 10.2174/0929866526666181128142401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 10/22/2018] [Accepted: 11/06/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Membrane proteins are crucial for cellular sensory cascades and metabolite transport, and hence are key pharmacological targets. Structural studies by traditional highresolution techniques are limited by the requirements for high purity and stability when handled in high concentration and nonnative buffers. Hence, there is a growing requirement for the use of alternate methods in a complementary but orthogonal approach to study the dynamic and functional aspects of membrane proteins in physiologically relevant conditions. In recent years, significant progress has been made in the field of X-ray radiolytic labeling in combination with mass spectroscopy, commonly known as X-ray Footprinting and Mass Spectrometry (XFMS), which provide residue-specific information on the solvent accessibility of proteins. In combination with both lowresolution biophysical methods and high-resolution structural data, XFMS is capable of providing valuable insights into structure and dynamics of membrane proteins, which have been difficult to obtain by standalone high-resolution structural techniques. The XFMS method has also demonstrated a unique capability for identification of structural waters and their dynamics in protein cavities at both a high degree of spatial and temporal resolution, and thus capable of identifying conformational hot-spots in transmembrane proteins. CONCLUSION We provide a perspective on the place of XFMS amongst other structural biology methods and showcase some of the latest developments in its usage for studying conformational changes in membrane proteins.
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Affiliation(s)
- Sayan Gupta
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
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29
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Ishiuchi SI, Sasaki Y, Lisy JM, Fujii M. Ion-peptide interactions between alkali metal ions and a termini-protected dipeptide: modeling a portion of the selectivity filter in K + channels. Phys Chem Chem Phys 2019; 21:561-571. [PMID: 30351321 DOI: 10.1039/c8cp05839c] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Potassium channels have the unique ability to allow the selective passage of potassium ions at near diffusion-free rates while inhibiting the passage of more abundant sodium ions. Local interactions between chemical functional groups and the ions are responsible for both selectivity and transport. As an initial step in characterizing these interactions, the structures of Na+ and K+ complexed to the Ac-Tyr-NHMe peptide have been determined from infrared laser spectroscopy and supporting ab initio calculations. Ac-Tyr-NHMe, a termini-protected peptide sequence, replicates the GYG portion of one of the four peptide chains comprising the selectivity filter of a K+ channel. This peptide contains two carbonyl groups, among the eight C[double bond, length as m-dash]O groups forming the S1 binding site of the selectivity filter. Three conformations have been identified for both ions by laser IR-IR double resonance methods. Two conformations have the ion bound to the two C[double bond, length as m-dash]O groups. The third conformation has, in addition, a cation-π interaction with the aromatic ring of tyrosine, i.e. tridentate binding. The relative contributions of the three conformers are approximately the same for K+Ac-Tyr-NHMe, while the tridentate conformer is preferred for Na+Ac-Tyr-NHMe. These differences will be discussed in the context of ion mobility and selectivity.
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Affiliation(s)
- Shun-Ichi Ishiuchi
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
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30
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Moradi S, Nowroozi A, Shahlaei M. Shedding light on the structural properties of lipid bilayers using molecular dynamics simulation: a review study. RSC Adv 2019; 9:4644-4658. [PMID: 35520151 PMCID: PMC9060685 DOI: 10.1039/c8ra08441f] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 03/12/2019] [Accepted: 01/16/2019] [Indexed: 12/20/2022] Open
Abstract
This review gives an overview about the some of the most important possible analyzes, technical challenges, and existing protocols that can be performed on the biological membrane by the molecular dynamics simulation.
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Affiliation(s)
- Sajad Moradi
- Nano Drug Delivery Research Center
- Kermanshah University of Medical Sciences
- Kermanshah
- Iran
| | - Amin Nowroozi
- Pharmaceutical Sciences Research Center
- Faculty of Pharmacy
- Kermanshah University of Medical Sciences
- Kermanshah
- Iran
| | - Mohsen Shahlaei
- Medical Biology Research Center
- Kermanshah University of Medical Sciences
- Kermanshah
- Iran
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31
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Mallikarjunaiah KJ, Kinnun JJ, Petrache HI, Brown MF. Flexible lipid nanomaterials studied by NMR spectroscopy. Phys Chem Chem Phys 2019; 21:18422-18457. [DOI: 10.1039/c8cp06179c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Advances in solid-state nuclear magnetic resonance spectroscopy inform the emergence of material properties from atomistic-level interactions in membrane lipid nanostructures.
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Affiliation(s)
- K. J. Mallikarjunaiah
- Department of Chemistry and Biochemistry
- University of Arizona
- Tucson
- USA
- Department of Physics
| | - Jacob J. Kinnun
- Department of Physics
- Indiana University-Purdue University
- Indianapolis
- USA
| | - Horia I. Petrache
- Department of Physics
- Indiana University-Purdue University
- Indianapolis
- USA
| | - Michael F. Brown
- Department of Chemistry and Biochemistry
- University of Arizona
- Tucson
- USA
- Department of Physics
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32
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Auger M, Lefèvre T, Otis F, Voyer N, Auger M. Lipid membrane interactions of a fluorinated peptide with potential ion channel-forming ability. Pept Sci (Hoboken) 2019. [DOI: 10.1002/pep2.24051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Maud Auger
- Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Département de Chimie, Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
| | - Thierry Lefèvre
- Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Département de Chimie, Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
| | - François Otis
- PROTEO, Département de chimie; Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
| | - Normand Voyer
- PROTEO, Département de chimie; Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
| | - Michèle Auger
- Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Département de Chimie, Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
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33
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Microfluidic Technologies and Platforms for Protein Crystallography. Bioanalysis 2019. [DOI: 10.1007/978-981-13-6229-3_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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34
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Elkins MR, Sergeyev IV, Hong M. Determining Cholesterol Binding to Membrane Proteins by Cholesterol 13C Labeling in Yeast and Dynamic Nuclear Polarization NMR. J Am Chem Soc 2018; 140:15437-15449. [PMID: 30338997 PMCID: PMC6361393 DOI: 10.1021/jacs.8b09658] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a general strategy for determining the cholesterol-binding site of eukaryotic membrane proteins in native-like lipid membranes by NMR spectroscopy. The strategy combines yeast biosynthetic 13C enrichment of cholesterol with detection of protein-cholesterol 13C-13C cross peaks in 2D correlation NMR spectra under the dynamic nuclear polarization (DNP) condition. Low-temperature DNP not only allows high-sensitivity detection of weak protein-cholesterol cross peaks in 2D spectra but also immobilizes cholesterol and protein to enable intermolecular distance measurements. We demonstrate this approach on the influenza M2 protein, which utilizes cholesterol to conduct membrane scission in the last step of virus budding and release from the host cell plasma membrane. A 13C-13C double-quantum filter was employed to significantly simplify the 2D 13C-13C correlation spectra and facilitate the identification of protein-cholesterol cross peaks. A number of cross peaks between the M2 transmembrane residues' side chains and the cholesterol sterol group were detected, which complement recently measured protein contacts to the isooctyl tail of cholesterol to define an extended binding interface. These results provide atomic-level evidence of M2-cholesterol interaction to cause membrane curvature and scission, and the approach is generally applicable to other eukaryotic membrane proteins for understanding the influence of cholesterol on membrane protein function.
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Affiliation(s)
- Matthew R. Elkins
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | | | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
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35
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Jaipuria G, Giller K, Leonov A, Becker S, Zweckstetter M. Insights into Cholesterol/Membrane Protein Interactions Using Paramagnetic Solid-State NMR. Chemistry 2018; 24:17606-17611. [PMID: 30255522 DOI: 10.1002/chem.201804550] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Indexed: 11/10/2022]
Abstract
Cholesterol is an essential component of animal cell membranes and impacts the structure and function of membrane proteins. But how cholesterol exerts its functions remains often enigmatic. Here, high-resolution solid-state NMR in combination with paramagnetic cholesterol analogues was shown to be a powerful approach to study the interaction of membrane proteins with cholesterol. Application of the method to the 169-residue translocator protein TSPO provides residue-specific information about its interaction with cholesterol. Comparison with NMR signal perturbations induced by diamagnetic cholesterol furthermore supports changes in the structure of mammalian TSPO caused by cholesterol binding.
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Affiliation(s)
- Garima Jaipuria
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
| | - Karin Giller
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Andrei Leonov
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Stefan Becker
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Markus Zweckstetter
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany.,Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
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36
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Mayo DJ, Sahu ID, Lorigan GA. Assessing topology and surface orientation of an antimicrobial peptide magainin 2 using mechanically aligned bilayers and electron paramagnetic resonance spectroscopy. Chem Phys Lipids 2018; 213:124-130. [DOI: 10.1016/j.chemphyslip.2018.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 04/13/2018] [Accepted: 04/20/2018] [Indexed: 12/13/2022]
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37
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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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38
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Chen W, Dev J, Mezhyrova J, Pan L, Piai A, Chou JJ. The Unusual Transmembrane Partition of the Hexameric Channel of the Hepatitis C Virus. Structure 2018; 26:627-634.e4. [PMID: 29551287 PMCID: PMC5884736 DOI: 10.1016/j.str.2018.02.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/24/2018] [Accepted: 02/09/2018] [Indexed: 01/14/2023]
Abstract
The p7 protein of the hepatitis C virus (HCV) can oligomerize in membrane to form cation channels. Previous studies showed that the channel assembly in detergent micelles adopts a unique flower-shaped oligomer, but the unusual architecture also presented problems for understanding how this viroporin resides in the membrane. Moreover, the oligomeric state of p7 remains controversial, as both hexamer and heptamer have been proposed. Here we address the above issues using p7 reconstituted in bicelles that mimic a lipid bilayer. We found, using a recently developed oligomer-labeling method, that p7 forms hexamers in the bicelles. Solvent paramagnetic relaxation enhancement analyses showed that the bilayer thickness around the HCV ion channel is substantially smaller than expected, and thus a significant portion of the previously assigned membrane-embedded region is solvent exposed. Our study provides an effective approach for characterizing the transmembrane partition of small ion channels in near lipid bilayer environment.
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Affiliation(s)
- Wen Chen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Jyoti Dev
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Julija Mezhyrova
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Liqiang Pan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Alessandro Piai
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - James J Chou
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 201203, China.
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39
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Li S, Li J, Tang J, Deng F. Host-guest interaction of styrene and ethylbenzene in MIL-53 studied by solid-state NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2018; 90:1-6. [PMID: 29316473 DOI: 10.1016/j.ssnmr.2017.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/22/2017] [Accepted: 12/22/2017] [Indexed: 06/07/2023]
Abstract
Solid-state NMR was utilized to explore the host-guest interaction between adsorbate and adsorbent at atomic level to understand the separation mechanism of styrene (St) and ethylbenzene (EB) in MIL-53(Al). 13C-27Al double-resonance NMR experiments revealed that the host-guest interaction between St and MIL-53 was much stronger than that of EB adsorption. In addition, 13C DIPSHIFT experiments suggested that the adsorbed St was less mobile than EB confined inside the MIL-53 pore. Furthermore, the host-guest interaction model between St, EB and MIL-53 was established on the basis of the spatial proximities information extracted from 2D 1H-1H homo-nuclear correlation NMR experiments. According to the experimental observation from solid-state NMR, it was found that the presence of π-π interaction between St and MIL-53 resulted in the stronger host-guest interaction and less mobility of St. This work provides direct experimental evidence for understanding the separation mechanism of St and EB using MIL-53 as an adsorbent.
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Affiliation(s)
- Shenhui Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Jing Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jing Tang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Feng Deng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China.
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40
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New insights into the influence of monofluorination on dimyristoylphosphatidylcholine membrane properties: A solid-state NMR study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:654-663. [DOI: 10.1016/j.bbamem.2017.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/29/2017] [Accepted: 12/04/2017] [Indexed: 10/18/2022]
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41
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Pandey MK, Hashi K, Ohki S, Nishijima G, Matsumoto S, Noguchi T, Deguchi K, Goto A, Shimizu T, Maeda H, Takahashi M, Yanagisawa Y, Yamazaki T, Iguchi S, Tanaka R, Nemoto T, Miyamoto T, Suematsu H, Saito K, Miki T, Nishiyama Y. 24 T High-Resolution and -Sensitivity Solid-State NMR Measurements of Low-Gamma Half-Integer Quadrupolar Nuclei 35Cl and 37Cl. ANAL SCI 2018; 32:1339-1345. [PMID: 27941265 DOI: 10.2116/analsci.32.1339] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Solid-state NMR observations of low-gamma half-integer quadrupolar nuclei, 35Cl and 37Cl, were demonstrated using a 24 T hybrid magnet (1H resonance frequency of 1.02 GHz) comprised of the high-temperature (HTS) and low-temperature (LTS) superconductors, and compared with results using a 14.1 T standard NMR magnet. While at 24 T the linewidth is 1.7 times narrower than that at 14.1 T, the gain in the sensitivity is 7.0 times because of enhanced polarization, reduced linewidth, and the use of larger rotor. A simple theoretical model was used to rationalize the sensitivity enhancements. The ratio of 35Cl and 37Cl quadrupolar couplings agrees well with the ratio of quadrupolar moments, and no isotope-dependent chemical shift has been observed. In addition, the 3QMAS spectrum of 35Cl is shown to demonstrate the high sensitivity rendered by the 24 T spectrometer.
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42
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Abstract
Biomolecular solid-state NMR experiments have traditionally been collected through detection of 13C or 15N nuclei. Since these nuclei have relatively low sensitivity stemming from their smaller gyromagnetic ratios relative to 1H, the time required to collect multi-dimensional datasets serves as a limitation to resonance assignment and structure determination. One improvement in the field has been to employ simultaneous or parallel acquisition techniques with the goal of acquiring more than one dataset at a time and therefore speeding up the overall data collection process. Central to these experiments is the cross-polarization (CP) element, which serves as a way to transfer magnetization between nuclei via magnetic dipolar couplings. In this chapter, we show how residual signal remaining after CP is a polarization source that can be used to acquire additional datasets. The setup of this class of experiments, referred to as Afterglow spectroscopy, is described and demonstrated using a membrane protein transporter involved in multidrug resistance.
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Affiliation(s)
- Gili Abramov
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY, 10003, USA
| | - Nathaniel J Traaseth
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY, 10003, USA.
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43
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Cardoso MH, Oshiro KG, Rezende SB, Cândido ES, Franco OL. The Structure/Function Relationship in Antimicrobial Peptides: What Can we Obtain From Structural Data? THERAPEUTIC PROTEINS AND PEPTIDES 2018; 112:359-384. [DOI: 10.1016/bs.apcsb.2018.01.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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44
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Gopinath T, Veglia G. Experimental Aspects of Polarization Optimized Experiments (POE) for Magic Angle Spinning Solid-State NMR of Microcrystalline and Membrane-Bound Proteins. Methods Mol Biol 2018; 1688:37-53. [PMID: 29151203 DOI: 10.1007/978-1-4939-7386-6_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Conventional NMR pulse sequences record one spectrum per experiment, while spending most of the time waiting for the spin system to return to the equilibrium. As a result, a full set of multidimensional NMR experiments for biological macromolecules may take up to several months to complete. Here, we present a practical guide for setting up a new class of MAS solid-state NMR experiments (POE or polarization optimized experiments) that enable the simultaneous acquisition of multiple spectra of proteins, accelerating data acquisition. POE exploit the long-lived 15N polarization of isotopically labeled proteins and enable one to obtain up to eight spectra, by concatenating classical NMR pulse sequences. This new strategy propels data throughput of solid-state NMR spectroscopy of fibers, microcrystalline preparations, as well as membrane proteins.
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Affiliation(s)
- T Gopinath
- Department of Biochemistry, Biophysics, and Molecular Biology, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Biophysics, and Molecular Biology, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA.
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
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45
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Baker LA, Sinnige T, Schellenberger P, de Keyzer J, Siebert CA, Driessen AJM, Baldus M, Grünewald K. Combined 1H-Detected Solid-State NMR Spectroscopy and Electron Cryotomography to Study Membrane Proteins across Resolutions in Native Environments. Structure 2017; 26:161-170.e3. [PMID: 29249608 PMCID: PMC5758107 DOI: 10.1016/j.str.2017.11.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/02/2017] [Accepted: 11/15/2017] [Indexed: 11/15/2022]
Abstract
Membrane proteins remain challenging targets for structural biology, despite much effort, as their native environment is heterogeneous and complex. Most methods rely on detergents to extract membrane proteins from their native environment, but this removal can significantly alter the structure and function of these proteins. Here, we overcome these challenges with a hybrid method to study membrane proteins in their native membranes, combining high-resolution solid-state nuclear magnetic resonance spectroscopy and electron cryotomography using the same sample. Our method allows the structure and function of membrane proteins to be studied in their native environments, across different spatial and temporal resolutions, and the combination is more powerful than each technique individually. We use the method to demonstrate that the bacterial membrane protein YidC adopts a different conformation in native membranes and that substrate binding to YidC in these native membranes differs from purified and reconstituted systems. CryoET and ssNMR give complementary information about proteins in native membranes One sample can be prepared for both methods without the use of detergents Hybrid method shows differences between purified and native preparations of YidC Sample preparation reduces costs and time and suggests new strategy for assignment
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Affiliation(s)
- Lindsay A Baker
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands; Oxford Particle Imaging Centre, Division of Structural Biology, University of Oxford, The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK.
| | - Tessa Sinnige
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Pascale Schellenberger
- Oxford Particle Imaging Centre, Division of Structural Biology, University of Oxford, The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Jeanine de Keyzer
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands; The Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 11, 9747 AG Groningen, the Netherlands
| | - C Alistair Siebert
- Oxford Particle Imaging Centre, Division of Structural Biology, University of Oxford, The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Arnold J M Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands; The Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 11, 9747 AG Groningen, the Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands.
| | - Kay Grünewald
- Oxford Particle Imaging Centre, Division of Structural Biology, University of Oxford, The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK.
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46
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Loquet A, Tolchard J, Berbon M, Martinez D, Habenstein B. Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy. J Vis Exp 2017:55779. [PMID: 28994783 PMCID: PMC5752270 DOI: 10.3791/55779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Supramolecular protein assemblies play fundamental roles in biological processes ranging from host-pathogen interaction, viral infection to the propagation of neurodegenerative disorders. Such assemblies consist in multiple protein subunits organized in a non-covalent way to form large macromolecular objects that can execute a variety of cellular functions or cause detrimental consequences. Atomic insights into the assembly mechanisms and the functioning of those macromolecular assemblies remain often scarce since their inherent insolubility and non-crystallinity often drastically reduces the quality of the data obtained from most techniques used in structural biology, such as X-ray crystallography and solution Nuclear Magnetic Resonance (NMR). We here present magic-angle spinning solid-state NMR spectroscopy (SSNMR) as a powerful method to investigate structures of macromolecular assemblies at atomic resolution. SSNMR can reveal atomic details on the assembled complex without size and solubility limitations. The protocol presented here describes the essential steps from the production of 13C/15N isotope-labeled macromolecular protein assemblies to the acquisition of standard SSNMR spectra and their analysis and interpretation. As an example, we show the pipeline of a SSNMR structural analysis of a filamentous protein assembly.
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Affiliation(s)
- Antoine Loquet
- Institute of Chemistry, Biology of Membranes, Nanoobjects, UMR5248 CNRS, Université de Bordeaux;
| | - James Tolchard
- Institute of Chemistry, Biology of Membranes, Nanoobjects, UMR5248 CNRS, Université de Bordeaux
| | - Melanie Berbon
- Institute of Chemistry, Biology of Membranes, Nanoobjects, UMR5248 CNRS, Université de Bordeaux
| | - Denis Martinez
- Institute of Chemistry, Biology of Membranes, Nanoobjects, UMR5248 CNRS, Université de Bordeaux
| | - Birgit Habenstein
- Institute of Chemistry, Biology of Membranes, Nanoobjects, UMR5248 CNRS, Université de Bordeaux;
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Molugu TR, Lee S, Brown MF. Concepts and Methods of Solid-State NMR Spectroscopy Applied to Biomembranes. Chem Rev 2017; 117:12087-12132. [PMID: 28906107 DOI: 10.1021/acs.chemrev.6b00619] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Concepts of solid-state NMR spectroscopy and applications to fluid membranes are reviewed in this paper. Membrane lipids with 2H-labeled acyl chains or polar head groups are studied using 2H NMR to yield knowledge of their atomistic structures in relation to equilibrium properties. This review demonstrates the principles and applications of solid-state NMR by unifying dipolar and quadrupolar interactions and highlights the unique features offered by solid-state 2H NMR with experimental illustrations. For randomly oriented multilamellar lipids or aligned membranes, solid-state 2H NMR enables direct measurement of residual quadrupolar couplings (RQCs) due to individual C-2H-labeled segments. The distribution of RQC values gives nearly complete profiles of the segmental order parameters SCD(i) as a function of acyl segment position (i). Alternatively, one can measure residual dipolar couplings (RDCs) for natural abundance lipid samples to obtain segmental SCH order parameters. A theoretical mean-torque model provides acyl-packing profiles representing the cumulative chain extension along the normal to the aqueous interface. Equilibrium structural properties of fluid bilayers and various thermodynamic quantities can then be calculated, which describe the interactions with cholesterol, detergents, peptides, and integral membrane proteins and formation of lipid rafts. One can also obtain direct information for membrane-bound peptides or proteins by measuring RDCs using magic-angle spinning (MAS) in combination with dipolar recoupling methods. Solid-state NMR methods have been extensively applied to characterize model membranes and membrane-bound peptides and proteins, giving unique information on their conformations, orientations, and interactions in the natural liquid-crystalline state.
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Affiliation(s)
- Trivikram R Molugu
- Department of Chemistry & Biochemistry and ‡Department of Physics, University of Arizona , Tucson, Arizona 85721, United States
| | - Soohyun Lee
- Department of Chemistry & Biochemistry and ‡Department of Physics, University of Arizona , Tucson, Arizona 85721, United States
| | - Michael F Brown
- Department of Chemistry & Biochemistry and ‡Department of Physics, University of Arizona , Tucson, Arizona 85721, United States
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Bacterial Filamentous Appendages Investigated by Solid-State NMR Spectroscopy. Methods Mol Biol 2017. [PMID: 28667627 DOI: 10.1007/978-1-4939-7033-9_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The assembly of filamentous appendages at the surface of bacteria is essential in many infection mechanisms. The extent of mechanical, dynamical, and functional properties of such appendages is very diverse, ranging from a structural scaffold of the pathogen-host cell interaction to cell motility, surface adhesion, or the export of virulence effectors. In particular, the architectures of several bacterial secretion systems have revealed the presence of filamentous architectures, known as pili, fimbriae, andneedles. At the macroscopic level, filamentous bacterial appendages appear as thin extracellular filaments of several nanometers in diameter and up to several microns in length. The structural characterization of these appendages at atomic-scale resolution represents an extremely challenging task because of their inherent noncrystallinity and very poor solubility. Here, we describe protocols based on recent advances in solid-state NMR spectroscopy to investigate the secondary structure, subunit-subunit protein interactions, symmetry parameters, and atomic architecture of bacterial filaments.
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49
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Mandal A, van der Wel PCA. MAS 1H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes. Biophys J 2017; 111:1965-1973. [PMID: 27806278 DOI: 10.1016/j.bpj.2016.09.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 09/09/2016] [Accepted: 09/21/2016] [Indexed: 10/20/2022] Open
Abstract
The lipid bilayer typical of hydrated biological membranes is characterized by a liquid-crystalline, highly dynamic state. Upon cooling or dehydration, these membranes undergo a cooperative transition to a rigidified, more-ordered, gel phase. This characteristic phase transition is of significant biological and biophysical interest, for instance in studies of freezing-tolerant organisms. Magic-angle-spinning (MAS) solid-state NMR (ssNMR) spectroscopy allows for the detection and characterization of the phase transitions over a wide temperature range. In this study we employ MAS 1H NMR to probe the phase transitions of both solvent molecules and different hydrated phospholipids, including tetraoleoyl cardiolipin (TOCL) and several phosphatidylcholine lipid species. The employed MAS NMR sample conditions cause a previously noted substantial reduction in the freezing point of the solvent phase. The effect on the solvent is caused by confinement of the aqueous solvent in the small and densely packed MAS NMR samples. In this study we report and examine how the freezing point depression also impacts the lipid phase transition, causing a ssNMR-observed reduction in the lipids' melting temperature (Tm). The molecular underpinnings of this phenomenon are discussed and compared with previous studies of membrane-associated water phases and the impact of membrane-protective cryoprotectants.
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Affiliation(s)
- Abhishek Mandal
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Patrick C A van der Wel
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
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50
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van der Cruijsen EAW, Prokofyev AV, Pongs O, Baldus M. Probing Conformational Changes during the Gating Cycle of a Potassium Channel in Lipid Bilayers. Biophys J 2017; 112:99-108. [PMID: 28076820 DOI: 10.1016/j.bpj.2016.12.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 11/08/2016] [Accepted: 12/01/2016] [Indexed: 01/10/2023] Open
Abstract
Ion conduction across the cellular membrane requires the simultaneous opening of activation and inactivation gates of the K+ channel pore. The bacterial KcsA channel has served as a powerful system for dissecting the structural changes that are related to four major functional states associated with K+ gating. Yet, the direct observation of the full gating cycle of KcsA has remained structurally elusive, and crystal structures mimicking these gating events require mutations in or stabilization of functionally relevant channel segments. Here, we found that changes in lipid composition strongly increased the KcsA open probability. This enabled us to probe all four major gating states in native-like membranes by combining electrophysiological and solid-state NMR experiments. In contrast to previous crystallographic views, we found that the selectivity filter and turret region, coupled to the surrounding bilayer, were actively involved in channel gating. The increase in overall steady-state open probability was accompanied by a reduction in activation-gate opening, underscoring the important role of the surrounding lipid bilayer in the delicate conformational coupling of the inactivation and activation gates.
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Affiliation(s)
- Elwin A W van der Cruijsen
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Alexander V Prokofyev
- Department of Physiology, Institute of Cellular Neurophysiology, University of the Saarland, Homburg, Germany
| | - Olaf Pongs
- Department of Physiology, Institute of Cellular Neurophysiology, University of the Saarland, Homburg, Germany.
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.
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