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Townsend JA, Marty MT. What's the defect? Using mass defects to study oligomerization of membrane proteins and peptides in nanodiscs with native mass spectrometry. Methods 2023; 218:1-13. [PMID: 37482149 PMCID: PMC10529358 DOI: 10.1016/j.ymeth.2023.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/20/2023] [Accepted: 07/03/2023] [Indexed: 07/25/2023] Open
Abstract
Many membrane proteins form functional complexes that are either homo- or hetero-oligomeric. However, it is challenging to characterize membrane protein oligomerization in intact lipid bilayers, especially for polydisperse mixtures. Native mass spectrometry of membrane proteins and peptides inserted in lipid nanodiscs provides a unique method to study the oligomeric state distribution and lipid preferences of oligomeric assemblies. To interpret these complex spectra, we developed novel data analysis methods using macromolecular mass defect analysis. Here, we provide an overview of how mass defect analysis can be used to study oligomerization in nanodiscs, discuss potential limitations in interpretation, and explore strategies to resolve these ambiguities. Finally, we review recent work applying this technique to studying formation of antimicrobial peptide, amyloid protein, and viroporin complexes with lipid membranes.
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Affiliation(s)
- Julia A Townsend
- Department of Chemistry and Biochemistry and Bio5 Institute, University of Arizona, Tucson, AZ 85721, USA
| | - Michael T Marty
- Department of Chemistry and Biochemistry and Bio5 Institute, University of Arizona, Tucson, AZ 85721, USA.
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2
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Sawczyc H, Heit S, Watts A. A comparative characterisation of commercially available lipid-polymer nanoparticles formed from model membranes. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:39-51. [PMID: 36786921 PMCID: PMC10039845 DOI: 10.1007/s00249-023-01632-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 02/15/2023]
Abstract
From the discovery of the first membrane-interacting polymer, styrene maleic-acid (SMA), there has been a rapid development of membrane solubilising polymers. These new polymers can solubilise membranes under a wide range of conditions and produce varied sizes of nanoparticles, yet there has been a lack of broad comparison between the common polymer types and solubilising conditions. Here, we present a comparative study on the three most common commercial polymers: SMA 3:1, SMA 2:1, and DIBMA. Additionally, this work presents, for the first time, a comparative characterisation of polymethacrylate copolymer (PMA). Absorbance and dynamic light scattering measurements were used to evaluate solubilisation across key buffer conditions in a simple, adaptable assay format that looked at pH, salinity, and divalent cation concentration. Lipid-polymer nanoparticles formed from SMA variants were found to be the most susceptible to buffer effects, with nanoparticles from either zwitterionic DMPC or POPC:POPG (3:1) bilayers only forming in low to moderate salinity (< 600 mM NaCl) and above pH 6. DIBMA-lipid nanoparticles could be formed above a pH of 5 and were stable in up to 4 M NaCl. Similarly, PMA-lipid nanoparticles were stable in all NaCl concentrations tested (up to 4 M) and a broad pH range (3-10). However, for both DIBMA and PMA nanoparticles there is a severe penalty observed for bilayer solubilisation in non-optimal conditions or when using a charged membrane. Additionally, lipid fluidity of the DMPC-polymer nanoparticles was analysed through cw-EPR, showing no cooperative gel-fluid transition as would be expected for native-like lipid membranes.
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Affiliation(s)
- Henry Sawczyc
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| | - Sabine Heit
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Anthony Watts
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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3
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Ghanam RH, Eastep GN, Saad JS. Structural Insights into the Mechanism of HIV-1 Tat Secretion from the Plasma Membrane. J Mol Biol 2023; 435:167880. [PMID: 36370804 PMCID: PMC9822876 DOI: 10.1016/j.jmb.2022.167880] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/27/2022] [Accepted: 11/04/2022] [Indexed: 11/11/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) trans-activator of transcription (Tat) is a small, intrinsically disordered basic protein that plays diverse roles in the HIV-1 replication cycle, including promotion of efficient viral RNA transcription. Tat is released by infected cells and subsequently absorbed by healthy cells, thereby contributing to HIV-1 pathogenesis including HIV-associated neurocognitive disorder. It has been shown that, in HIV-1-infected primary CD4 T-cells, Tat accumulates at the plasma membrane (PM) for secretion, a mechanism mediated by phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). However, the structural basis for Tat interaction with the PM and thereby secretion is lacking. Herein, we employed NMR and biophysical methods to characterize Tat86 (86 amino acids) interactions with PI(4,5)P2 and lipid nanodiscs (NDs). Our data revealed that Arg49, Lys50 and Lys51 (RKK motif) constitute the PI(4,5)P2 binding site, that Tat86 interaction with lipid NDs is dependent on PI(4,5)P2 and phosphatidylserine (PS), and that the arginine-rich motif (RRQRRR) preferentially interacts with PS. Furthermore, we show that Trp11, previously implicated in Tat secretion, penetrates deeply in the membrane; substitution of Trp11 severely reduced Tat86 interaction with membranes. Deletion of the entire highly basic region and Trp11 completely abolished Tat86 binding to lipid NDs. Our data support a mechanism by which HIV-1 Tat secretion from the PM is mediated by a tripartite signal consisting of binding of the RKK motif to PI(4,5)P2, arginine-rich motif to PS, and penetration of Trp11 in the membrane. Altogether, these findings provide new insights into the molecular requirements for Tat binding to membranes during secretion.
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Affiliation(s)
- Ruba H Ghanam
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Gunnar N Eastep
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Jamil S Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
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4
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Zaborowska M, Matyszewska D, Bilewicz R. Model Lipid Raft Membranes for Embedding Integral Membrane Proteins: Reconstitution of HMG-CoA Reductase and Its Inhibition by Statins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13888-13897. [PMID: 36335466 PMCID: PMC9671039 DOI: 10.1021/acs.langmuir.2c02115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 09/28/2022] [Indexed: 06/16/2023]
Abstract
For the first time, HMG-CoA reductase, the membrane protein responsible for cholesterol synthesis, was incorporated into a lipid membrane consisting of DOPC:Chol:SM at a 1:1:1 molar ratio, which mimics the lipid rafts of cell membranes. The membrane containing the protein was generated in the form of either a proteoliposomes or a film obtained by spreading the proteoliposomes at the air-water interface to prepare a protein-rich and stable lipid layer over time. The lipid vesicle parameters were characterized using dynamic light scattering (DLS) and fluorescence microscopy. The incorporation of HMG-CoA reductase was reflected in the increased size of the proteoliposomes compared to that of the empty liposomes of model rafts. Enzyme reconstitution was confirmed by measuring the activity of NADPH, which participates in the catalytic process. The thin lipid raft films formed by spreading liposomes and proteoliposomes at the air-water interface were investigated using the Langmuir technique. The activities of the HMG-CoA reductase films were preserved over time, and the two lipid raft systems, nanoparticles and films, were exposed to solutions of fluvastatin, a HMG-CoA reductase inhibitor commonly used in the treatment of hypercholesterolemia. Both lipid raft systems constructed were useful membrane models for the determination of reductase activity and for monitoring the statin inhibitory effects and may be used for investigating other integral membrane proteins during exposure to inhibitors/activators considered to be potential drugs.
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Affiliation(s)
| | - Dorota Matyszewska
- Faculty
of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02089Warsaw, Poland
| | - Renata Bilewicz
- Faculty
of Chemistry, University of Warsaw, Pasteura 1, 02093Warsaw, Poland
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5
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de Grip WJ, Ganapathy S. Rhodopsins: An Excitingly Versatile Protein Species for Research, Development and Creative Engineering. Front Chem 2022; 10:879609. [PMID: 35815212 PMCID: PMC9257189 DOI: 10.3389/fchem.2022.879609] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 05/16/2022] [Indexed: 01/17/2023] Open
Abstract
The first member and eponym of the rhodopsin family was identified in the 1930s as the visual pigment of the rod photoreceptor cell in the animal retina. It was found to be a membrane protein, owing its photosensitivity to the presence of a covalently bound chromophoric group. This group, derived from vitamin A, was appropriately dubbed retinal. In the 1970s a microbial counterpart of this species was discovered in an archaeon, being a membrane protein also harbouring retinal as a chromophore, and named bacteriorhodopsin. Since their discovery a photogenic panorama unfolded, where up to date new members and subspecies with a variety of light-driven functionality have been added to this family. The animal branch, meanwhile categorized as type-2 rhodopsins, turned out to form a large subclass in the superfamily of G protein-coupled receptors and are essential to multiple elements of light-dependent animal sensory physiology. The microbial branch, the type-1 rhodopsins, largely function as light-driven ion pumps or channels, but also contain sensory-active and enzyme-sustaining subspecies. In this review we will follow the development of this exciting membrane protein panorama in a representative number of highlights and will present a prospect of their extraordinary future potential.
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Affiliation(s)
- Willem J. de Grip
- Leiden Institute of Chemistry, Department of Biophysical Organic Chemistry, Leiden University, Leiden, Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Srividya Ganapathy
- Department of Imaging Physics, Delft University of Technology, Netherlands
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6
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Watkins EB, Dennison AJC, Majewski J. Binding of Cholera Toxin B-Subunit to a Ganglioside GM1-Functionalized PEG-Tethered Lipid Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6959-6966. [PMID: 35604017 PMCID: PMC9179658 DOI: 10.1021/acs.langmuir.2c00499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/10/2022] [Indexed: 05/25/2023]
Abstract
We report neutron reflectometry (NR) studies of polyethylene glycol (PEG)-tethered model lipid membranes at the solid-liquid interface and of cholera toxin's B-subunit (CTxB) binding to tethered membranes containing ganglioside GM1 receptors. First, tethered polymer brushes were formed by grafting silane-functionalized PEG lipopolymers to quartz from solution. Subsequent deposition of lipids by Langmuir-Blodgett/Langmuir-Schaefer (LB/LS) resulted in a tethered bilayer structure separated from the solid support by a hydrated PEG layer. NR revealed that the tethers formed a highly hydrated polymer brush, uniformly separating the bilayer from the underlying solid substrate. Further, the lipid bilayer did not significantly perturb the brush's conformation relative to a free brush. Biological functionality of the tethered bilayers was verified by interacting CTxB, with ganglioside GM1 receptors incorporated into the bilayer. The surface coverage of CTxB bound to the lipid membrane, θCTB= 0.58 ± 0.08, was consistent with the coverage predicted for random sequential absorption, and toxin binding did not impact the membrane conformation.
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Affiliation(s)
- Erik B. Watkins
- MPA-11:
Materials Synthesis and Integrated Devices, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Institut
Laue-Langevin, BP 156, 38042 Grenoble, France
| | - Andrew J. C. Dennison
- Dept.
Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7HG, U.K.
| | - Jaroslaw Majewski
- Division
of Molecular and Cellular Biosciences, National
Science Foundation, Alexandria 22303, Virginia, United States
- Theoretical
Biology and Biophysics at Los Alamos National Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Department
of Chemical and Biological Engineering and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
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7
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Lethcoe K, Fox CA, Ryan RO. Foam fractionation of a recombinant biosurfactant apolipoprotein. J Biotechnol 2022; 343:25-31. [PMID: 34808251 PMCID: PMC8714704 DOI: 10.1016/j.jbiotec.2021.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/10/2021] [Accepted: 11/13/2021] [Indexed: 01/12/2023]
Abstract
Locusta migratoria apolipophorin III (apoLp-III) possesses the ability to exist as a water soluble amphipathic α-helix bundle and a lipid surface seeking apolipoprotein. The intrinsic ability of apoLp-III to transform phospholipid vesicles into reconstituted discoidal high-density lipoproteins (rHDL) has led to myriad applications. To improve the yield of recombinant apoLp-III, studies were performed in a bioreactor. Induction of apoLp-III expression generated a protein product that is secreted from E. coli into the culture medium. Interaction of apoLp-III with gas and liquid components in media produced large quantities of thick foam. A continuous foam fractionation process yielded a foamate containing apoLp-III as the sole major protein component. The yield of recombinant apoLp-III was ~0.2 g / liter bacterial culture. Mass spectrometry analysis verified the identity of the target protein and indicated no modifications or changes to apoLp-III occurred as a result of foam fractionation. The functional ability of apoLp-III to induce rHDL formation was evaluated by incubating foam fractionated apoLp-III with phosphatidylcholine vesicles. FPLC size exclusion chromatography revealed a single major population of particles in the size range of rHDL. The results described offer a novel approach to bioreactor-based apoLp-III production that takes advantage of its intrinsic biosurfactant properties.
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Affiliation(s)
- Kyle Lethcoe
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, USA
| | - Colin A Fox
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, USA
| | - Robert O Ryan
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, USA.
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8
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Islam MS, Gaston JP, Baker MAB. Fluorescence Approaches for Characterizing Ion Channels in Synthetic Bilayers. MEMBRANES 2021; 11:857. [PMID: 34832086 PMCID: PMC8619978 DOI: 10.3390/membranes11110857] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 12/12/2022]
Abstract
Ion channels are membrane proteins that play important roles in a wide range of fundamental cellular processes. Studying membrane proteins at a molecular level becomes challenging in complex cellular environments. Instead, many studies focus on the isolation and reconstitution of the membrane proteins into model lipid membranes. Such simpler, in vitro, systems offer the advantage of control over the membrane and protein composition and the lipid environment. Rhodopsin and rhodopsin-like ion channels are widely studied due to their light-interacting properties and are a natural candidate for investigation with fluorescence methods. Here we review techniques for synthesizing liposomes and for reconstituting membrane proteins into lipid bilayers. We then summarize fluorescence assays which can be used to verify the functionality of reconstituted membrane proteins in synthetic liposomes.
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Affiliation(s)
- Md. Sirajul Islam
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, NSW 2052, Australia; (M.S.I.); (J.P.G.)
| | - James P. Gaston
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, NSW 2052, Australia; (M.S.I.); (J.P.G.)
| | - Matthew A. B. Baker
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, NSW 2052, Australia; (M.S.I.); (J.P.G.)
- CSIRO Synthetic Biology Future Science Platform, GPO Box 2583, Brisbane, QLD 4001, Australia
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9
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Conti Nibali S, Di Rosa MC, Rauh O, Thiel G, Reina S, De Pinto V. Cell-free electrophysiology of human VDACs incorporated into nanodiscs: An improved method. ACTA ACUST UNITED AC 2021; 1:None. [PMID: 34568862 PMCID: PMC8448298 DOI: 10.1016/j.bpr.2021.100002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/25/2021] [Indexed: 12/15/2022]
Abstract
Voltage-dependent anion-selective channel (VDAC) is one of the main proteins of the outer mitochondrial membrane of all eukaryotes, where it forms aqueous, voltage-sensitive, and ion-selective channels. Its electrophysiological properties have been thoroughly analyzed with the planar lipid bilayer technique. To date, however, available results are based on isolations of VDACs from tissue or from recombinant VDACs produced in bacterial systems. It is well known that the cytosolic overexpression of highly hydrophobic membrane proteins often results in the formation of inclusion bodies containing insoluble aggregates. Purification of properly folded proteins and restoration of their full biological activity requires several procedures that considerably lengthen experimental times. To overcome these restraints, we propose a one-step reaction that combines in vitro cell-free protein expression with nanodisc technology to obtain human VDAC isoforms directly integrated in a native-like lipid bilayer. Reconstitution assays into artificial membranes confirm the reliability of this new methodological approach and provide results comparable to those of VDACs prepared with traditional protein isolation and reconstitution protocols. The use of membrane-mimicking nanodisc systems represents a breakthrough in VDAC electrophysiology and may be adopted to further structural studies.
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Affiliation(s)
- Stefano Conti Nibali
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Maria Carmela Di Rosa
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Oliver Rauh
- Membrane Biophysics and Center for Synthetic Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | - Gerhard Thiel
- Membrane Biophysics and Center for Synthetic Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | - Simona Reina
- Department of Biological, Geological and Environmental Sciences, Section of Molecular Biology, University of Catania, Catania, Italy.,we.MitoBiotech.srl, Catania, Italy
| | - Vito De Pinto
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy.,we.MitoBiotech.srl, Catania, Italy
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10
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Zhao L, Tao J, Huang Y, Zhu K, Du Y, Hao D, Liu H, Zhang R, Ma G. Tailored nanodisc immobilization for one-step purification and reconstitution of cytochrome P450: A tool for membrane proteins' hard cases. J Sep Sci 2021; 44:3429-3440. [PMID: 34313005 DOI: 10.1002/jssc.202100284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/25/2021] [Accepted: 07/19/2021] [Indexed: 11/07/2022]
Abstract
A novel nanodisc-based immobilization method was developed for high-efficient purification and reconstitution of cytochrome P450 in one step. Using membrane scaffold protein containing a histidine tag, charged-nanodiscs were prepared in the form of self-assembly of lipid-protein nanoparticles. Their properties including the particle diameter and its distribution and Zeta potential were controlled well by adjusting molar ratios of phospholipids to membrane scaffold protein. At an optimum lipid-to-membrane scaffold protein molar ratio of 60:1, uniformly regular-shaped and discoidal nanodiscs with an average particle diameter of 10 nm and Zeta potential of -19 mV were obtained. They can be well fractionated by size exclusion chromatography. Charged-nanodiscs were successfully immobilized onto Ni-chelating microspheres via histidine tags with a density of 6.6 mg membrane scaffold protein/mL gel. After being packed in a column, chromatography studies demonstrated that this nanodisc-immobilized chromatographic medium had a specific binding to cytochrome P450 in rat liver microsome. Nanodiscs containing cytochrome P450 can be furthermore eluted from the column with a diameter of about 87.0 nm and height of about 8.0 nm, respectively. The purity of cytochrome P450 after purification increased 25 folds strikingly. This nanodisc-immobilized chromatography method is promising for the one-step purification and reconstitution of membrane protein.
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Affiliation(s)
- Lan Zhao
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, P. R. China
| | - Jiaoli Tao
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, P. R. China.,School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, P. R. China
| | - Yongdong Huang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, P. R. China
| | - Kai Zhu
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, P. R. China
| | - Yuxiang Du
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, P. R. China.,School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, P. R. China
| | - Dongxia Hao
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, P. R. China
| | - Hongying Liu
- School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, P. R. China
| | - Rongyue Zhang
- Department of Applied Chemistry, Beijing Institute of Petrochemical Technology, Beijing, P. R. China
| | - Guanghui Ma
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, P. R. China.,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, P. R. China
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11
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Manna P, Davies T, Hoffmann M, Johnson MP, Schlau-Cohen GS. Membrane-dependent heterogeneity of LHCII characterized using single-molecule spectroscopy. Biophys J 2021; 120:3091-3102. [PMID: 34214527 DOI: 10.1016/j.bpj.2021.06.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/16/2021] [Accepted: 06/08/2021] [Indexed: 10/21/2022] Open
Abstract
In green plants, light harvesting complex of Photosystem II (LHCII) absorbs and transports excitation energy toward the photosynthetic reaction centers and serves as a site for energy-dependent nonphotochemical quenching (qE), the photoprotective dissipation of energy as heat. LHCII is thought to activate dissipation through conformational changes that change the photophysical behaviors. Understanding this balance requires a characterization of how the conformations of LHCII, and thus its photophysics, are influenced by individual factors within the membrane environment. Here, we used ensemble and single-molecule fluorescence to characterize the excited-state lifetimes and switching kinetics of LHCII embedded in nanodisc- and liposome-based model membranes of various sizes and lipid compositions. As the membrane area decreased, the quenched population and the rate of conformational dynamics both increased because of interactions with other proteins, the aqueous solution, and/or disordered lipids. Although the conformational states and dynamics were similar in both thylakoid and asolectin lipids, photodegradation increased with thylakoid lipids, likely because of their charge and pressure properties. Collectively, these findings demonstrate the ability of membrane environments to tune the conformations and photophysics of LHCII.
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Affiliation(s)
- Premashis Manna
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Thomas Davies
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Madeline Hoffmann
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
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12
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Liang Q, He J, Zhao X, Xue Y, Zuo H, Xu R, Jin Y, Wang J, Li Q, Zhao X. Selective Discovery of GPCR Ligands within DNA-Encoded Chemical Libraries Derived from Natural Products: A Case Study on Antagonists of Angiotensin II Type I Receptor. J Med Chem 2021; 64:4196-4205. [PMID: 33784102 DOI: 10.1021/acs.jmedchem.1c00123] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Natural products have failed to meet the urgent need for drug discovery in recent decades due to limited resources, necessitating new strategies for re-establishing the key role of natural products in hit screening. This work introduced DNA-encoding techniques into the synthesis of phenolic acid-focused libraries containing 32 000 diverse compounds. Online selection of the library using immobilized angiotensin II type I receptor (AT1R) resulted in seven phenolic acid derivatives. The half-maximal concentration (IC50) of hit 1 for the right shift of the [125I]-Sar1-AngII competition curve was 19.6 nM. Pharmacological examination of renovascular hypertensive rats demonstrated that hit 1 significantly lowered the blood pressure of the animals without changing their heart rates. These results were used to create a general strategy for rapid and unbiased discovery of hits derived from natural products with high throughput and efficiency.
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Affiliation(s)
- Qi Liang
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Jianyu He
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Xue Zhao
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Yan Xue
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Haiyue Zuo
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Ru Xu
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Yan Jin
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Jing Wang
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Qian Li
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Xinfeng Zhao
- College of Life Sciences, Northwest University, Xi'an 710069, China
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13
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Fogeron ML, Lecoq L, Cole L, Harbers M, Böckmann A. Easy Synthesis of Complex Biomolecular Assemblies: Wheat Germ Cell-Free Protein Expression in Structural Biology. Front Mol Biosci 2021; 8:639587. [PMID: 33842544 PMCID: PMC8027086 DOI: 10.3389/fmolb.2021.639587] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 01/20/2021] [Indexed: 12/18/2022] Open
Abstract
Cell-free protein synthesis (CFPS) systems are gaining more importance as universal tools for basic research, applied sciences, and product development with new technologies emerging for their application. Huge progress was made in the field of synthetic biology using CFPS to develop new proteins for technical applications and therapy. Out of the available CFPS systems, wheat germ cell-free protein synthesis (WG-CFPS) merges the highest yields with the use of a eukaryotic ribosome, making it an excellent approach for the synthesis of complex eukaryotic proteins including, for example, protein complexes and membrane proteins. Separating the translation reaction from other cellular processes, CFPS offers a flexible means to adapt translation reactions to protein needs. There is a large demand for such potent, easy-to-use, rapid protein expression systems, which are optimally serving protein requirements to drive biochemical and structural biology research. We summarize here a general workflow for a wheat germ system providing examples from the literature, as well as applications used for our own studies in structural biology. With this review, we want to highlight the tremendous potential of the rapidly evolving and highly versatile CFPS systems, making them more widely used as common tools to recombinantly prepare particularly challenging recombinant eukaryotic proteins.
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Affiliation(s)
- Marie-Laure Fogeron
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, Lyon, France
| | - Lauriane Lecoq
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, Lyon, France
| | - Laura Cole
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, Lyon, France
| | - Matthias Harbers
- CellFree Sciences, Yokohama, Japan
- RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, Japan
| | - Anja Böckmann
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, Lyon, France
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14
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Jakubec M, Bariås E, Furse S, Govasli ML, George V, Turcu D, Iashchishyn IA, Morozova-Roche LA, Halskau Ø. Cholesterol-containing lipid nanodiscs promote an α-synuclein binding mode that accelerates oligomerization. FEBS J 2021; 288:1887-1905. [PMID: 32892498 DOI: 10.1111/febs.15551] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 07/28/2020] [Accepted: 09/01/2020] [Indexed: 01/09/2023]
Abstract
Dysregulation of the biosynthesis of cholesterol and other lipids has been implicated in many neurological diseases, including Parkinson's disease. Misfolding of α-synuclein (α-Syn), the main actor in Parkinson's disease, is associated with changes in a lipid environment. However, the exact molecular mechanisms underlying cholesterol effect on α-Syn binding to lipids as well as α-Syn oligomerization and fibrillation remain elusive, as does the relative importance of cholesterol compared to other factors. We probed the interactions and fibrillation behaviour of α-Syn using styrene-maleic acid nanodiscs, containing zwitterionic and anionic lipid model systems with and without cholesterol. Surface plasmon resonance and thioflavin T fluorescence assays were employed to monitor α-Syn binding, as well as fibrillation in the absence and presence of membrane models. 1 H-15 N-correlated NMR was used to monitor the fold of α-Syn in response to nanodisc binding, determining individual residue apparent affinities for the nanodisc-contained bilayers. The addition of cholesterol inhibited α-Syn interaction with lipid bilayers and, however, significantly promoted α-Syn fibrillation, with a more than a 20-fold reduction of lag times before fibrillation onset. When α-Syn bilayer interactions were analysed at an individual residue level by solution-state NMR, we observed two different effects of cholesterol. In nanodiscs made of DOPC, the addition of cholesterol modulated the NAC part of α-Syn, leading to stronger interaction of this region with the lipid bilayer. In contrast, in the nanodiscs comprising DOPC, DOPE and DOPG, the NAC part was mostly unaffected by the presence of cholesterol, while the binding of the N and the C termini was both inhibited.
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Affiliation(s)
- Martin Jakubec
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
| | - Espen Bariås
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
| | - Samuel Furse
- Department of Molecular Biology, University of Bergen, Norway
| | - Morten L Govasli
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
- Division of Infection and Immunity, University College London, London, UK
| | - Vinnit George
- Department of Chemistry, University of Bergen, Norway
| | - Diana Turcu
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
| | - Igor A Iashchishyn
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | | | - Øyvind Halskau
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
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15
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Richter AM, Possling A, Malysheva N, Yousef KP, Herbst S, von Kleist M, Hengge R. Local c-di-GMP Signaling in the Control of Synthesis of the E. coli Biofilm Exopolysaccharide pEtN-Cellulose. J Mol Biol 2020; 432:4576-4595. [PMID: 32534064 PMCID: PMC7397504 DOI: 10.1016/j.jmb.2020.06.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/20/2020] [Accepted: 06/08/2020] [Indexed: 12/17/2022]
Abstract
In many bacteria, the biofilm-promoting second messenger c-di-GMP is produced and degraded by multiple diguanylate cyclases (DGC) and phosphodiesterases (PDE), respectively. High target specificity of some of these enzymes has led to theoretical concepts of "local" c-di-GMP signaling. In Escherichia coli K-12, which has 12 DGCs and 13 PDEs, a single DGC, DgcC, is specifically required for the biosynthesis of the biofilm exopolysaccharide pEtN-cellulose without affecting the cellular c-di-GMP pool, but the mechanistic basis of this target specificity has remained obscure. DGC activity of membrane-associated DgcC, which is demonstrated in vitro in nanodiscs, is shown to be necessary and sufficient to specifically activate cellulose biosynthesis in vivo. DgcC and a particular PDE, PdeK (encoded right next to the cellulose operon), directly interact with cellulose synthase subunit BcsB and with each other, thus establishing physical proximity between cellulose synthase and a local source and sink of c-di-GMP. This arrangement provides a localized, yet open source of c-di-GMP right next to cellulose synthase subunit BcsA, which needs allosteric activation by c-di-GMP. Through mathematical modeling and simulation, we demonstrate that BcsA binding from the low cytosolic c-di-GMP pool in E. coli is negligible, whereas a single c-di-GMP molecule that is produced and released in direct proximity to cellulose synthase increases the probability of c-di-GMP binding to BcsA several hundred-fold. This local c-di-GMP signaling could provide a blueprint for target-specific second messenger signaling also in other bacteria where multiple second messenger producing and degrading enzymes exist.
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Affiliation(s)
- Anja M Richter
- Institute of Biology/Microbiology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Department of Materials and the Environment, Bundesanstalt für Materialforschung und -Prüfung, 12205 Berlin, Germany
| | - Alexandra Possling
- Institute of Biology/Microbiology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Nadezhda Malysheva
- Department of Mathematics and Computer Science, Freie Universität Berlin, 14195 Berlin, Germany; MF1 Bioinformatics, Robert-Koch-Institut, 13353 Berlin, Germany
| | - Kaveh P Yousef
- Department of Mathematics and Computer Science, Freie Universität Berlin, 14195 Berlin, Germany
| | - Susanne Herbst
- Institute of Biology/Microbiology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Max von Kleist
- Department of Mathematics and Computer Science, Freie Universität Berlin, 14195 Berlin, Germany; MF1 Bioinformatics, Robert-Koch-Institut, 13353 Berlin, Germany
| | - Regine Hengge
- Institute of Biology/Microbiology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
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16
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Murphy RE, Saad JS. The Interplay between HIV-1 Gag Binding to the Plasma Membrane and Env Incorporation. Viruses 2020; 12:E548. [PMID: 32429351 PMCID: PMC7291237 DOI: 10.3390/v12050548] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 12/21/2022] Open
Abstract
Advancement in drug therapies and patient care have drastically improved the mortality rates of HIV-1 infected individuals. Many of these therapies were developed or improved upon by using structure-based techniques, which underscore the importance of understanding essential mechanisms in the replication cycle of HIV-1 at the structural level. One such process which remains poorly understood is the incorporation of the envelope glycoprotein (Env) into budding virus particles. Assembly of HIV particles is initiated by targeting of the Gag polyproteins to the inner leaflet of the plasma membrane (PM), a process mediated by the N-terminally myristoylated matrix (MA) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). There is strong evidence that formation of the Gag lattice on the PM is a prerequisite for the incorporation of Env into budding particles. It is also suggested that Env incorporation is mediated by an interaction between its cytoplasmic tail (gp41CT) and the MA domain of Gag. In this review, we highlight the latest developments and current efforts to understand the interplay between gp41CT, MA, and the membrane during assembly. Elucidation of the molecular determinants of Gag-Env-membrane interactions may help in the development of new antiviral therapeutic agents that inhibit particle assembly, Env incorporation and ultimately virus production.
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Affiliation(s)
| | - Jamil S. Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
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17
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Chuang ST, Cruz S, Narayanaswami V. Reconfiguring Nature's Cholesterol Accepting Lipoproteins as Nanoparticle Platforms for Transport and Delivery of Therapeutic and Imaging Agents. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E906. [PMID: 32397159 PMCID: PMC7279153 DOI: 10.3390/nano10050906] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 12/13/2022]
Abstract
Apolipoproteins are critical structural and functional components of lipoproteins, which are large supramolecular assemblies composed predominantly of lipids and proteins, and other biomolecules such as nucleic acids. A signature feature of apolipoproteins is the preponderance of amphipathic α-helical motifs that dictate their ability to make extensive non-covalent inter- or intra-molecular helix-helix interactions in lipid-free states or helix-lipid interactions with hydrophobic biomolecules in lipid-associated states. This review focuses on the latter ability of apolipoproteins, which has been capitalized on to reconstitute synthetic nanoscale binary/ternary lipoprotein complexes composed of apolipoproteins/peptides and lipids that mimic native high-density lipoproteins (HDLs) with the goal to transport drugs. It traces the historical development of our understanding of these nanostructures and how the cholesterol accepting property of HDL has been reconfigured to develop them as drug-loading platforms. The review provides the structural perspective of these platforms with different types of apolipoproteins and an overview of their synthesis. It also examines the cargo that have been loaded into the core for therapeutic and imaging purposes. Finally, it lays out the merits and challenges associated with apolipoprotein-based nanostructures with a future perspective calling for a need to develop "zip-code"-based delivery for therapeutic and diagnostic applications.
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Affiliation(s)
| | | | - Vasanthy Narayanaswami
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Blvd, Long Beach, CA 90840, USA; (S.T.C.); (S.C.)
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18
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Murphy RE, Samal AB, Vlach J, Mas V, Prevelige PE, Saad JS. Structural and biophysical characterizations of HIV-1 matrix trimer binding to lipid nanodiscs shed light on virus assembly. J Biol Chem 2019; 294:18600-18612. [PMID: 31640987 PMCID: PMC6901326 DOI: 10.1074/jbc.ra119.010997] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/16/2019] [Indexed: 12/17/2022] Open
Abstract
During the late phase of the HIV-1 replication cycle, the viral Gag polyproteins are targeted to the plasma membrane for assembly. The Gag-membrane interaction is mediated by binding of Gag's N-terminal myristoylated matrix (MA) domain to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). The viral envelope (Env) glycoprotein is then recruited to the assembly sites and incorporated into budding particles. Evidence suggests that Env incorporation is mediated by interactions between Gag's MA domain and the cytoplasmic tail of the gp41 subunit of Env (gp41CT). MA trimerization appears to be an obligatory step for this interaction. Insufficient production of a recombinant MA trimer and unavailability of a biologically relevant membrane system have been barriers to detailed structural and biophysical characterization of the putative MA-gp41CT-membrane interactions. Here, we engineered a stable recombinant HIV-1 MA trimer construct by fusing a foldon domain (FD) of phage T4 fibritin to the MA C terminus. Results from NMR experiments confirmed that the FD attachment does not adversely alter the MA structure. Employing hydrogen-deuterium exchange MS, we identified an MA-MA interface in the MA trimer that is implicated in Gag assembly and Env incorporation. Utilizing lipid nanodiscs as a membrane mimetic, we show that the MA trimer binds to membranes 30-fold tighter than does the MA monomer and that incorporation of PI(4,5)P2 and phosphatidylserine enhances the binding of MA to nanodiscs. These findings advance our understanding of a fundamental mechanism in HIV-1 assembly and provide a template for investigating the interaction of MA with gp41CT.
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Affiliation(s)
- R Elliot Murphy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Alexandra B Samal
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Jiri Vlach
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Vicente Mas
- Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Peter E Prevelige
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Jamil S Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294.
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19
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Syu GD, Wang SC, Ma G, Liu S, Pearce D, Prakash A, Henson B, Weng LC, Ghosh D, Ramos P, Eichinger D, Pino I, Dong X, Xiao J, Wang S, Tao N, Kim KS, Desai PJ, Zhu H. Development and application of a high-content virion display human GPCR array. Nat Commun 2019; 10:1997. [PMID: 31040288 PMCID: PMC6491619 DOI: 10.1038/s41467-019-09938-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 04/05/2019] [Indexed: 12/21/2022] Open
Abstract
Human G protein-coupled receptors (GPCRs) respond to various ligands and stimuli. However, GPCRs rely on membrane for proper folding, making their biochemical properties difficult to study. By displaying GPCRs in viral envelopes, we fabricated a Virion Display (VirD) array containing 315 non-olfactory human GPCRs for functional characterization. Using this array, we found that 10 of 20 anti-GPCR mAbs were ultra-specific. We further demonstrated that those failed in the mAb assays could recognize their canonical ligands, suggesting proper folding. Next, using two peptide ligands on the VirD-GPCR array, we identified expected interactions and novel interactions. Finally, we screened the array with group B Streptococcus, a major cause of neonatal meningitis, and demonstrated that inhibition of a newly identified target, CysLTR1, reduced bacterial penetration both in vitro and in vivo. We believe that the VirD-GPCR array holds great potential for high-throughput screening for small molecule drugs, affinity reagents, and ligand deorphanization.
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Affiliation(s)
- Guan-Da Syu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Center for High-Throughput Biology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Viral Oncology Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA
| | - Shih-Chin Wang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Guangzhong Ma
- Biodesign Center for Bioelectronics and Biosensors, Arizona State University, Tempe, AZ, 85287, USA
| | - Shuang Liu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Center for High-Throughput Biology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Donna Pearce
- Division of Paediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Atish Prakash
- Division of Paediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Brandon Henson
- Viral Oncology Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA
| | - Lien-Chun Weng
- Viral Oncology Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA
| | - Devlina Ghosh
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Pedro Ramos
- CDI Laboratories, Inc., Mayaguez, Puerto Rico, 00682, USA
| | | | - Ignacio Pino
- CDI Laboratories, Inc., Mayaguez, Puerto Rico, 00682, USA
| | - Xinzhong Dong
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Shaopeng Wang
- Biodesign Center for Bioelectronics and Biosensors, Arizona State University, Tempe, AZ, 85287, USA
| | - Nongjian Tao
- Biodesign Center for Bioelectronics and Biosensors, Arizona State University, Tempe, AZ, 85287, USA
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Kwang Sik Kim
- Division of Paediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
| | - Prashant J Desai
- Viral Oncology Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.
| | - Heng Zhu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Center for High-Throughput Biology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Viral Oncology Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.
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20
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Mosslehy W, Voskoboynikova N, Colbasevici A, Ricke A, Klose D, Klare JP, Mulkidjanian AY, Steinhoff HJ. Conformational Dynamics of Sensory Rhodopsin II in Nanolipoprotein and Styrene-Maleic Acid Lipid Particles. Photochem Photobiol 2019; 95:1195-1204. [PMID: 30849183 DOI: 10.1111/php.13096] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 03/03/2019] [Indexed: 02/01/2023]
Abstract
Styrene-maleic acid lipid particles (SMALPs) provide stable water-soluble nanocontainers for lipid-encased membrane proteins. Possible effects of the SMA-stabilized lipid environment on the interaction dynamics between functionally coupled membrane proteins remain to be elucidated. The photoreceptor sensory rhodopsin II, NpSRII and its cognate transducer, NpHtrII, of Natronomonas pharaonis form a transmembrane complex, NpSRII2 /NpHtrII2 that plays a key role in negative phototaxis and provides a unique model system to study the light-induced transfer of a conformational signal between two integral membrane proteins. Photon absorption induces transient structural changes in NpSRII comprising an outward movement of helix F that cause further conformational alterations in NpHtrII. We applied site-directed spin labeling and time-resolved optical and EPR spectroscopy to compare the conformational dynamics of NpSRII2 /NpHtrII2 reconstituted in SMALPs with that of nanolipoprotein particle and liposome preparations. NpSRII and NpSRII2 /NpHtrII2 show similar photocycles in liposomes and nanolipoprotein particles. An accelerated decay of the M photointermediate found for SMALPs can be explained by a high local proton concentration provided by the carboxylic groups of the SMA polymer. Light-induced large-scale conformational changes of NpSRII2 /NpHtrII2 observed in liposomes and nanolipoprotein particles are affected in SMALPs, indicating restrictions of the protein's conformational freedom.
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Affiliation(s)
- Wageiha Mosslehy
- Department of Physics, University of Osnabrück, Osnabrück, Germany
| | | | | | - Adrian Ricke
- Department of Physics, University of Osnabrück, Osnabrück, Germany
| | - Daniel Klose
- Department of Physics, University of Osnabrück, Osnabrück, Germany.,Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland
| | - Johann P Klare
- Department of Physics, University of Osnabrück, Osnabrück, Germany
| | - Armen Y Mulkidjanian
- Department of Physics, University of Osnabrück, Osnabrück, Germany.,School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
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21
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Harding BD, Dixit G, Burridge KM, Sahu ID, Dabney-Smith C, Edelmann RE, Konkolewicz D, Lorigan GA. Characterizing the structure of styrene-maleic acid copolymer-lipid nanoparticles (SMALPs) using RAFT polymerization for membrane protein spectroscopic studies. Chem Phys Lipids 2018; 218:65-72. [PMID: 30528635 DOI: 10.1016/j.chemphyslip.2018.12.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 12/25/2022]
Abstract
Membrane proteins play an important role in maintaining the structure and physiology of an organism. Despite their significance, spectroscopic studies involving membrane proteins remain challenging due to the difficulties in mimicking their native lipid bilayer environment. Membrane mimetic systems such as detergent micelles, liposomes, bicelles, nanodiscs, lipodisqs have improved the solubility and folding properties of the membrane proteins for structural studies, however, each mimetic system suffers from its own limitations. In this study, using three different lipid environments, vesicles were titrated with styrene-maleic acid (StMA) copolymer leading to a homogeneous SMALP system (∼10 nm) at a weight ratio of 1:1.5 (vesicle: StMA solution). A combination of Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) was used to characterize these SMALPs. We used a controlled synthesis mechanism to synthesize StMA based block copolymers called reversible addition-fragmentation chain transfer polymerization (RAFT) SMALPs. Incorporation of the Voltage Sensor Domain of KCNQ1 (Q1-VSD) into RAFT SMALPs indicates that this is a promising application of this system to study membrane proteins using different biophysical techniques. V165C in Q1-VSD corresponding to the hydrophobic region was incorporated into the SMALP system. Continuous Wave-Electron Paramagnetic Resonance (CW-EPR) line shape analysis showed line shape broadening, exposing a lower rigid component and a faster component of the spin label.
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Affiliation(s)
- Benjamin D Harding
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, United States
| | - Gunjan Dixit
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, United States
| | - Kevin M Burridge
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, United States
| | - Indra D Sahu
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, United States
| | - Carole Dabney-Smith
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, United States
| | - Richard E Edelmann
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, United States
| | - Dominik Konkolewicz
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, United States.
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH, 45056, United States.
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22
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Tutkus M, Akhtar P, Chmeliov J, Görföl F, Trinkunas G, Lambrev PH, Valkunas L. Fluorescence Microscopy of Single Liposomes with Incorporated Pigment-Proteins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14410-14418. [PMID: 30380887 DOI: 10.1021/acs.langmuir.8b02307] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Reconstitution of transmembrane proteins into liposomes is a widely used method to study their behavior under conditions closely resembling the natural ones. However, this approach does not allow precise control of the liposome size, reconstitution efficiency, and the actual protein-to-lipid ratio in the formed proteoliposomes, which might be critical for some applications and/or interpretation of data acquired during the spectroscopic measurements. Here, we present a novel strategy employing methods of proteoliposome preparation, fluorescent labeling, purification, and surface immobilization that allow us to quantify these properties using fluorescence microscopy at the single-liposome level and for the first time apply it to study photosynthetic pigment-protein complexes LHCII. We show that LHCII proteoliposome samples, even after purification with a density gradient, always contain a fraction of nonreconstituted protein and are extremely heterogeneous in both protein density and liposome sizes. This strategy enables quantitative analysis of the reconstitution efficiency of different protocols and precise fluorescence spectroscopic study of various transmembrane proteins in a controlled nativelike environment.
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Affiliation(s)
- Marijonas Tutkus
- Department of Molecular Compound Physics , Centre for Physical Sciences and Technology , Saulėtekio Avenue 3 , LT-10257 Vilnius , Lithuania
| | - Parveen Akhtar
- Biological Research Centre , Hungarian Academy of Sciences , Temesvári körút 62 , 6726 Szeged , Hungary
| | - Jevgenij Chmeliov
- Department of Molecular Compound Physics , Centre for Physical Sciences and Technology , Saulėtekio Avenue 3 , LT-10257 Vilnius , Lithuania
- Institute of Chemical Physics, Faculty of Physics , Vilnius University , Saulėtekio Avenue 9-III , LT-10222 Vilnius , Lithuania
| | - Fanni Görföl
- Biological Research Centre , Hungarian Academy of Sciences , Temesvári körút 62 , 6726 Szeged , Hungary
| | - Gediminas Trinkunas
- Department of Molecular Compound Physics , Centre for Physical Sciences and Technology , Saulėtekio Avenue 3 , LT-10257 Vilnius , Lithuania
| | - Petar H Lambrev
- Biological Research Centre , Hungarian Academy of Sciences , Temesvári körút 62 , 6726 Szeged , Hungary
| | - Leonas Valkunas
- Department of Molecular Compound Physics , Centre for Physical Sciences and Technology , Saulėtekio Avenue 3 , LT-10257 Vilnius , Lithuania
- Institute of Chemical Physics, Faculty of Physics , Vilnius University , Saulėtekio Avenue 9-III , LT-10222 Vilnius , Lithuania
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23
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Carnevale LN, Arango AS, Arnold WR, Tajkhorshid E, Das A. Endocannabinoid Virodhamine Is an Endogenous Inhibitor of Human Cardiovascular CYP2J2 Epoxygenase. Biochemistry 2018; 57:6489-6499. [PMID: 30285425 PMCID: PMC6262108 DOI: 10.1021/acs.biochem.8b00691] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The human body contains endogenous cannabinoids (endocannabinoids) that elicit effects similar to those of Δ9-tetrahydrocanabinol, the principal bioactive component of cannabis. The endocannabinoid virodhamine (O-AEA) is the constitutional isomer of the well-characterized cardioprotective and anti-inflammatory endocannabinoid anandamide (AEA). The chemical structures of O-AEA and AEA contain arachidonic acid (AA) and ethanolamine; however, AA in O-AEA is connected to ethanolamine via an ester linkage, whereas AA in AEA is connected through an amide linkage. O-AEA is involved in regulating blood pressure and cardiovascular function. We show that O-AEA is found at levels 9.6-fold higher than that of AEA in porcine left ventricle. On a separate note, the cytochrome P450 (CYP) epoxygenase CYP2J2 is the most abundant CYP in the heart where it catalyzes the metabolism of AA and AA-derived eCBs to bioactive epoxides that are involved in diverse cardiovascular functions. Herein, using competitive binding studies, kinetic metabolism measurements, molecular dynamics, and wound healing assays, we have shown that O-AEA is an endogenous inhibitor of CYP2J2 epoxygenase. As a result, the role of O-AEA as an endogenous eCB inhibitor of CYP2J2 may provide a new mode of regulation to control the activity of cardiovascular CYP2J2 in vivo and suggests a potential cross-talk between the cardiovascular endocannabinoids and the cytochrome P450 system.
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Affiliation(s)
- Lauren N. Carnevale
- Department of Biochemistry, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
| | - Andres S. Arango
- Center for Biophysics and Computational Biology, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
- Beckman Institute for Advanced Science and Technology, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
| | - William R. Arnold
- Department of Biochemistry, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
| | - Emad Tajkhorshid
- Center for Biophysics and Computational Biology, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
- Beckman Institute for Advanced Science and Technology, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
- Department of Bioengineering, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
| | - Aditi Das
- Department of Comparative Biosciences, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
- Department of Biochemistry, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
- Center for Biophysics and Computational Biology, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
- Beckman Institute for Advanced Science and Technology, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana IL 61801
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Altering the edge chemistry of bicelles with peptoids. Chem Phys Lipids 2018; 217:43-50. [PMID: 30391486 DOI: 10.1016/j.chemphyslip.2018.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 09/10/2018] [Accepted: 10/23/2018] [Indexed: 01/23/2023]
Abstract
Cell function is tied to the interactions that occur within and across the cell membrane. Therefore, understanding membrane-affiliated interactions is important to many biomedical applications. Advancing the body of knowledge about these interactions will lead to discoveries in biomarker detection and therapeutic targets for disease detection and treatment. Model membrane systems are an effective way to study membrane proteins for such discoveries, allowing for stable protein structure and maintaining native activity. Bicelles, disc-shaped lipid bilayers created by combining long- and short-chain phospholipids, are the model membrane system of focus in this study. Bicelles are accessible from both sides and have a wide size range, which makes them attractive for studying membrane interactions without affecting function. In this work, bicelles were functionalized with peptoids to alter the edge chemistry. Peptoids are suitable for this application because of the large diversity of available side chain chemistries that can be easily incorporated in a sequence-specific manner. The peptoid sequence consists of three functional regions to promote insertion into the edge of bicelles. The insertion sequence at the C-terminus contains two alkyl chains and two hydrophobic, chiral aromatic groups that anchor into the bicelle edge. The facially amphipathic helix contains chiral aromatic groups on one side that interact with the lipid tails and positively charged groups on the other side, which interact with the lipid head groups. Thiol groups are included at the N-terminus to allow for visualization of peptoid location in the bicelle. Bicelle morphology and size were assessed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Peptoid location in the bicelle was determined by attachment of gold nanoparticles, which confirmed preferential incorporation of the peptoid into the bicelle edge with 82% specificity. Additionally, the peptoid-functionalized bicelles are of similar size and morphology to non-functionalized bicelles. Results from this study show that peptoid-functionalized bicelles are a promising model membrane system with potential applications in biosensors or bioseparations.
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Sahoo BR, Genjo T, Cox SJ, Stoddard AK, Anantharamaiah GM, Fierke C, Ramamoorthy A. Nanodisc-Forming Scaffold Protein Promoted Retardation of Amyloid-Beta Aggregation. J Mol Biol 2018; 430:4230-4244. [PMID: 30170005 DOI: 10.1016/j.jmb.2018.08.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/23/2018] [Accepted: 08/16/2018] [Indexed: 10/28/2022]
Abstract
Peptidic nanodiscs are useful membrane mimetic tools for structural and functional studies of membrane proteins, and membrane interacting peptides including amyloids. Here, we demonstrate anti-amyloidogenic activities of a nanodisc-forming 18-residue peptide (denoted as 4F), both in lipid-bound and lipid-free states by using Alzheimer's amyloid-beta (Aβ40) peptide as an example. Fluorescence-based amyloid fibrillation kinetic assays showed a significant delay in Aβ40 amyloid aggregation by the 4F peptide. In addition, 4F-encased lipid nanodiscs, at an optimal concentration of 4F (>20 μM) and nanodisc size (<10 nm), significantly affect amyloid fibrillation. A comparison of experimental results obtained from nanodiscs with that obtained from liposomes revealed a substantial inhibitory efficacy of 4F-lipid nanodiscs against Aβ40 aggregation and were also found to be suitable to trap Aβ40 intermediates. A combination of atomistic molecular dynamics simulations with NMR and circular dichroism experimental results exhibited a substantial change in Aβ40 conformation upon 4F binding through electrostatic and π-π interactions. Specifically, the 4F peptide was found to interfere with the central β-sheet-forming residues of Aβ40 through substantial hydrogen, π-π, and π-alkyl interactions. Fluorescence experiments and coarse-grained molecular dynamics simulations showed the formation of a ternary complex, where Aβ40 binds to the proximity of peptidic belt and membrane surface that deaccelerate amyloid fibrillation. Electron microscopy images revealed short and thick amyloid fibers of Aβ40 formed in the presence of 4F or 4F-lipid nanodsics. These findings could aid in the development of amyloid inhibitors as well as in stabilizing Aβ40 intermediates for high-resolution structural and neurobiological studies.
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Affiliation(s)
- Bikash Ranjan Sahoo
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Biophysics Program, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Takuya Genjo
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Biophysics Program, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Sarah J Cox
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Andrea K Stoddard
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | | | - Carol Fierke
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Department of Chemistry, University of Texas A&M, College Station, TX 77843-3255, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Biophysics Program, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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Rondelli V, Del Favero E, Brocca P, Fragneto G, Trapp M, Mauri L, Ciampa M, Romani G, Braun C, Winterstein L, Schroeder I, Thiel G, Moroni A, Cantu' L. Directional K+ channel insertion in a single phospholipid bilayer: Neutron reflectometry and electrophysiology in the joint exploration of a model membrane functional platform. Biochim Biophys Acta Gen Subj 2018; 1862:1742-1750. [DOI: 10.1016/j.bbagen.2018.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/27/2018] [Accepted: 05/07/2018] [Indexed: 01/05/2023]
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Herbst S, Lorkowski M, Sarenko O, Nguyen TKL, Jaenicke T, Hengge R. Transmembrane redox control and proteolysis of PdeC, a novel type of c-di-GMP phosphodiesterase. EMBO J 2018; 37:e97825. [PMID: 29514851 PMCID: PMC5897775 DOI: 10.15252/embj.201797825] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 01/31/2018] [Accepted: 02/08/2018] [Indexed: 12/17/2022] Open
Abstract
The nucleotide second messenger c-di-GMP nearly ubiquitously promotes bacterial biofilm formation, with enzymes that synthesize and degrade c-di-GMP being controlled by diverse N-terminal sensor domains. Here, we describe a novel class of widely occurring c-di-GMP phosphodiesterases (PDE) that feature a periplasmic "CSS domain" with two highly conserved cysteines that is flanked by two transmembrane regions (TM1 and TM2) and followed by a cytoplasmic EAL domain with PDE activity. Using PdeC, one of the five CSS domain PDEs of Escherichia coli K-12, we show that DsbA/DsbB-promoted disulfide bond formation in the CSS domain reduces PDE activity. By contrast, the free thiol form is enzymatically highly active, with the TM2 region promoting dimerization. Moreover, this form is processed by periplasmic proteases DegP and DegQ, yielding a highly active TM2 + EAL fragment that is slowly removed by further proteolysis. Similar redox control and proteolysis was also observed for a second CSS domain PDE, PdeB. At the physiological level, CSS domain PDEs modulate production and supracellular architecture of extracellular matrix polymers in the deeper layers of mature E. coli biofilms.
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Affiliation(s)
- Susanne Herbst
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Martin Lorkowski
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Olga Sarenko
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Thi Kim Loan Nguyen
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Tina Jaenicke
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, Germany
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Faas R, Kiefer D, Job L, Pohle A, Moß K, Henkel M, Hausmann R. Time-course and degradation rate of membrane scaffold protein (MSP1D1) during recombinant production. ACTA ACUST UNITED AC 2018; 17:45-48. [PMID: 29379767 PMCID: PMC5773449 DOI: 10.1016/j.btre.2017.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/24/2017] [Accepted: 12/13/2017] [Indexed: 11/15/2022]
Abstract
Relevant efficiency parameters, productivities and production rates for recombinant MSP1D1 are presented for the first time. Time-course of MSP1D1 concentration was quantified post-induction in comparison to a reference protein. Calculation of specific production rates confirm that degradation is the reason for decreased yields during MSP1D1 expression.
Membrane scaffold proteins (MSPs) are synthetic derivatives of apolipoprotein A-I, a major protein component of human high-density lipoprotein complexes. The most common among these is the variant MSP1D1, which has been in the focus of research on membrane mimetics in the past. As such, the amphipathic MSP1D1 has the ability to self-assemble in the presence of synthetic phospholipids into discoidal nanoparticles, so called nanodiscs. The recombinant production of MSP is exclusively reported using a standard laboratory expression system of the pET family. However, strong variations in both yield and achieved concentration as well as complications related to unspecific degradation are commonly reported. In addition, the time-course of recombinant protein as well as specific protein yields have not yet been quantified conclusively. In this study, the time-course of MSP1D1 concentration was investigated in a standard pET expression system in terms of quantification of production and degradation rates in comparison to a reference protein (eGFP).
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Affiliation(s)
- Ramona Faas
- Institute of Food Science and Biotechnology (150), Department of Bioprocess Engineering (150k), University of Hohenheim, Fruwirthstraße 12, 70599, Stuttgart, Germany
| | - Dirk Kiefer
- Institute of Food Science and Biotechnology (150), Department of Bioprocess Engineering (150k), University of Hohenheim, Fruwirthstraße 12, 70599, Stuttgart, Germany
| | - Laura Job
- Institute of Food Science and Biotechnology (150), Department of Bioprocess Engineering (150k), University of Hohenheim, Fruwirthstraße 12, 70599, Stuttgart, Germany
| | - Annelie Pohle
- Institute of Food Science and Biotechnology (150), Department of Bioprocess Engineering (150k), University of Hohenheim, Fruwirthstraße 12, 70599, Stuttgart, Germany
| | - Karin Moß
- Institute of Food Science and Biotechnology (150), Department of Bioprocess Engineering (150k), University of Hohenheim, Fruwirthstraße 12, 70599, Stuttgart, Germany
| | - Marius Henkel
- Institute of Food Science and Biotechnology (150), Department of Bioprocess Engineering (150k), University of Hohenheim, Fruwirthstraße 12, 70599, Stuttgart, Germany
| | - Rudolf Hausmann
- Institute of Food Science and Biotechnology (150), Department of Bioprocess Engineering (150k), University of Hohenheim, Fruwirthstraße 12, 70599, Stuttgart, Germany
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Ravula T, Hardin NZ, Ramadugu SK, Ramamoorthy A. pH Tunable and Divalent Metal Ion Tolerant Polymer Lipid Nanodiscs. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:10655-10662. [PMID: 28920693 DOI: 10.1021/acs.langmuir.7b02887] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The development and applications of detergent-free membrane mimetics have been the focus for the high-resolution structural and functional studies on membrane proteins. The introduction of lipid nanodiscs has attracted new attention toward the structural biology of membrane proteins and also enabled biomedical applications. Lipid nanodiscs provide a native lipid bilayer environment similar to the cell membrane surrounded by a belt made up of proteins or peptides. Recent studies have shown that the hydrolyzed form of styrene maleic anhydride copolymer (SMA) has the ability to form lipid nanodiscs and has several advantages over protein or peptide based nanodiscs. SMA polymer lipid nanodiscs have become very important for structural biology and nanobiotechnological applications. However, applications of the presently available polymer nanodiscs are limited by their instability toward divalent metal ions and acidic conditions. To overcome the limitations of SMA nanodiscs and to broaden the potential applications of polymer nanodiscs, the present study investigates the tunability of SMA polymer nanodiscs by systematically modifying the maleic acid functional group. The two newly developed polymers and subsequent lipid nanodiscs were characterized using solid-state NMR, FT-IR, TEM, and DLS experiments. The pH dependence and metal ion stability of these nanodiscs were studied using static light scattering and FTIR. The reported polymer nanodiscs exhibit unique pH dependent stability based on the modified functional group and show a high tolerance toward divalent metal ions. We also show these tunable nanodiscs can be used to encapsulate and stabilize a polyphenolic natural product curcumin.
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Affiliation(s)
- Thirupathi Ravula
- Biophysics Program and Department of Chemistry, The University of Michigan , Ann Arbor, Michigan 48109-1055, United States
| | - Nathaniel Z Hardin
- Biophysics Program and Department of Chemistry, The University of Michigan , Ann Arbor, Michigan 48109-1055, United States
| | - Sudheer Kumar Ramadugu
- Biophysics Program and Department of Chemistry, The University of Michigan , Ann Arbor, Michigan 48109-1055, United States
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of Chemistry, The University of Michigan , Ann Arbor, Michigan 48109-1055, United States
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30
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Kar UK, Simonian M, Whitelegge JP. Integral membrane proteins: bottom-up, top-down and structural proteomics. Expert Rev Proteomics 2017; 14:715-723. [PMID: 28737967 DOI: 10.1080/14789450.2017.1359545] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
INTRODUCTION Integral membrane proteins and lipids constitute the bilayer membranes that surround cells and sub-cellular compartments, and modulate movements of molecules and information between them. Since membrane protein drug targets represent a disproportionately large segment of the proteome, technical developments need timely review. Areas covered: Publically available resources such as Pubmed were surveyed. Bottom-up proteomics analyses now allow efficient extraction and digestion such that membrane protein coverage is essentially complete, making up around one third of the proteome. However, this coverage relies upon hydrophilic loop regions while transmembrane domains are generally poorly covered in peptide-based strategies. Top-down mass spectrometry where the intact membrane protein is fragmented in the gas phase gives good coverage in transmembrane regions, and membrane fractions are yielding to high-throughput top-down proteomics. Exciting progress in native mass spectrometry of membrane protein complexes is providing insights into subunit stoichiometry and lipid binding, and cross-linking strategies are contributing critical in-vivo information. Expert commentary: It is clear from the literature that integral membrane proteins have yielded to advanced techniques in protein chemistry and mass spectrometry, with applications limited only by the imagination of investigators. Key advances toward translation to the clinic are emphasized.
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Affiliation(s)
- Upendra K Kar
- a Department of Pharmaceutical Sciences, College of Pharmacy , University of Arkansas for Medical Sciences , Little Rock , AR , USA
| | - Margaret Simonian
- b NPI-Semel Institute , University of California Los Angeles , Los Angeles , CA , USA
| | - Julian P Whitelegge
- b NPI-Semel Institute , University of California Los Angeles , Los Angeles , CA , USA
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31
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Rehan S, Paavilainen VO, Jaakola VP. Functional reconstitution of human equilibrative nucleoside transporter-1 into styrene maleic acid co-polymer lipid particles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1059-1065. [DOI: 10.1016/j.bbamem.2017.02.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 01/30/2017] [Accepted: 02/26/2017] [Indexed: 12/14/2022]
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32
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Asadi J, Ferguson S, Raja H, Hacker C, Marius P, Ward R, Pliotas C, Naismith J, Lucocq J. Enhanced imaging of lipid rich nanoparticles embedded in methylcellulose films for transmission electron microscopy using mixtures of heavy metals. Micron 2017; 99:40-48. [PMID: 28419915 PMCID: PMC5465805 DOI: 10.1016/j.micron.2017.03.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 02/01/2023]
Abstract
Uranyl acetate/tungsten double stains are proposed for imaging lipid rich nanoparticle in TEM. Combined with methylcellulose embedment, the technique enhances membrane contrast. The technique works for liposomes, nanodiscs and bicelles. The double staining should improve quantification of lipid rich nanoparticles.
Synthetic and naturally occurring lipid-rich nanoparticles are of wide ranging importance in biomedicine. They include liposomes, bicelles, nanodiscs, exosomes and virus particles. The quantitative study of these particles requires methods for high-resolution visualization of the whole population. One powerful imaging method is cryo-EM of vitrified samples, but this is technically demanding, requires specialized equipment, provides low contrast and does not reveal all particles present in a population. Another approach is classical negative stain-EM, which is more accessible but is difficult to standardize for larger lipidic structures, which are prone to artifacts of structure collapse and contrast variability. A third method uses embedment in methylcellulose films containing uranyl acetate as a contrasting agent. Methylcellulose embedment has been widely used for contrasting and supporting cryosections but only sporadically for visualizing lipid rich vesicular structures such as endosomes and exosomes. Here we present a simple methylcellulose-based method for routine and comprehensive visualization of synthetic lipid rich nanoparticles preparations, such as liposomes, bicelles and nanodiscs. It combines a novel double-staining mixture of uranyl acetate (UA) and tungsten-based electron stains (namely phosphotungstic acid (PTA) or sodium silicotungstate (STA)) with methylcellulose embedment. While the methylcellulose supports the delicate lipid structures during drying, the addition of PTA or STA to UA provides significant enhancement in lipid structure display and contrast as compared to UA alone. This double staining method should aid routine structural evaluation and quantification of lipid rich nanoparticles structures.
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Affiliation(s)
- Jalal Asadi
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK
| | - Sophie Ferguson
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK
| | - Hussain Raja
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK
| | - Christian Hacker
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK
| | - Phedra Marius
- Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, St. Andrews, Scotland, UK
| | - Richard Ward
- Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, St. Andrews, Scotland, UK
| | - Christos Pliotas
- Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, St. Andrews, Scotland, UK
| | - James Naismith
- Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, St. Andrews, Scotland, UK
| | - John Lucocq
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK.
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Abstract
Membrane proteins play a most important part in metabolism, signaling, cell motility, transport, development, and many other biochemical and biophysical processes which constitute fundamentals of life on the molecular level. Detailed understanding of these processes is necessary for the progress of life sciences and biomedical applications. Nanodiscs provide a new and powerful tool for a broad spectrum of biochemical and biophysical studies of membrane proteins and are commonly acknowledged as an optimal membrane mimetic system that provides control over size, composition, and specific functional modifications on the nanometer scale. In this review we attempted to combine a comprehensive list of various applications of nanodisc technology with systematic analysis of the most attractive features of this system and advantages provided by nanodiscs for structural and mechanistic studies of membrane proteins.
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Affiliation(s)
- Ilia G Denisov
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
| | - Stephen G Sligar
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
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Chadwick AC, Jensen DR, Hanson PJ, Lange PT, Proudfoot SC, Peterson FC, Volkman BF, Sahoo D. NMR Structure of the C-Terminal Transmembrane Domain of the HDL Receptor, SR-BI, and a Functionally Relevant Leucine Zipper Motif. Structure 2017; 25:446-457. [PMID: 28162952 DOI: 10.1016/j.str.2017.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/23/2016] [Accepted: 01/05/2017] [Indexed: 01/26/2023]
Abstract
The interaction of high-density lipoprotein (HDL) with its receptor, scavenger receptor BI (SR-BI), is critical for lowering plasma cholesterol levels and reducing the risk for cardiovascular disease. The HDL/SR-BI complex facilitates delivery of cholesterol into cells and is likely mediated by receptor dimerization. This work describes the use of nuclear magnetic resonance (NMR) spectroscopy to generate the first high-resolution structure of the C-terminal transmembrane domain of SR-BI. This region of SR-BI harbors a leucine zipper dimerization motif, which when mutated impairs the ability of the receptor to bind HDL and mediate cholesterol delivery. These losses in function correlate with the inability of SR-BI to form dimers. We also identify juxtamembrane regions of the extracellular domain of SR-BI that may interact with the lipid surface to facilitate cholesterol transport functions of the receptor.
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Affiliation(s)
- Alexandra C Chadwick
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Davin R Jensen
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Paul J Hanson
- Division of Endocrinology, Metabolism & Clinical Nutrition, Department of Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Philip T Lange
- Division of Endocrinology, Metabolism & Clinical Nutrition, Department of Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Sarah C Proudfoot
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Francis C Peterson
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Daisy Sahoo
- Division of Endocrinology, Metabolism & Clinical Nutrition, Department of Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA; Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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Structure and lipid-binding properties of the kindlin-3 pleckstrin homology domain. Biochem J 2016; 474:539-556. [PMID: 27974389 PMCID: PMC5290484 DOI: 10.1042/bcj20160791] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/04/2016] [Accepted: 12/14/2016] [Indexed: 12/11/2022]
Abstract
Kindlins co-activate integrins alongside talin. They possess, like talin, a FERM domain (4.1-erythrin–radixin–moiesin domain) comprising F0–F3 subdomains, but with a pleckstrin homology (PH) domain inserted in the F2 subdomain that enables membrane association. We present the crystal structure of murine kindlin-3 PH domain determined at a resolution of 2.23 Å and characterise its lipid binding using biophysical and computational approaches. Molecular dynamics simulations suggest flexibility in the PH domain loops connecting β-strands forming the putative phosphatidylinositol phosphate (PtdInsP)-binding site. Simulations with PtdInsP-containing bilayers reveal that the PH domain associates with PtdInsP molecules mainly via the positively charged surface presented by the β1–β2 loop and that it binds with somewhat higher affinity to PtdIns(3,4,5)P3 compared with PtdIns(4,5)P2. Surface plasmon resonance (SPR) with lipid headgroups immobilised and the PH domain as an analyte indicate affinities of 300 µM for PtdIns(3,4,5)P3 and 1 mM for PtdIns(4,5)P2. In contrast, SPR studies with an immobilised PH domain and lipid nanodiscs as the analyte show affinities of 0.40 µM for PtdIns(3,4,5)P3 and no affinity for PtdIns(4,5)P2 when the inositol phosphate constitutes 5% of the total lipids (∼5 molecules per nanodisc). Reducing the PtdIns(3,4,5)P3 composition to 1% abolishes nanodisc binding to the PH domain, as does site-directed mutagenesis of two lysines within the β1–β2 loop. Binding of PtdIns(3,4,5)P3 by a canonical PH domain, Grp1, is not similarly influenced by SPR experimental design. These data suggest a role for PtdIns(3,4,5)P3 clustering in the binding of some PH domains and not others, highlighting the importance of lipid mobility and clustering for the biophysical assessment of protein–membrane interactions.
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Veugelen S, Dewilde M, De Strooper B, Chávez-Gutiérrez L. Screening and Characterization Strategies for Nanobodies Targeting Membrane Proteins. Methods Enzymol 2016; 584:59-97. [PMID: 28065273 DOI: 10.1016/bs.mie.2016.10.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
The study of membrane protein function and structure requires their successful detection, expression, solubilization, and/or reconstitution, which poses a challenging task and relies on the availability of suitable tools. Several research groups have successfully applied Nanobodies in the purification, as well as the functional and structural characterization of membrane proteins. Nanobodies are small, single-chain antibody fragments originating from camelids presenting on average a longer CDR3 which enables them to bind in cavities and clefts (such as active and allosteric sites). Notably, Nanobodies generally bind conformational epitopes making them very interesting tools to stabilize, dissect, and characterize specific protein conformations. In the clinic, several Nanobodies are under evaluation either as potential drug candidates or as diagnostic tools. In recent years, we have successfully generated high-affinity, conformation-sensitive anti-γ-secretase Nanobodies. γ-Secretase is a multimeric membrane protease involved in processing of the amyloid precursor protein with high clinical relevance as mutations in its catalytic subunit (Presenilin) cause early-onset Alzheimer's disease. Advancing our knowledge on the mechanisms governing γ-secretase intramembrane proteolysis through various strategies may lead to novel therapeutic avenues for Alzheimer's disease. In this chapter, we present the strategies we have developed and applied for the screening and characterization of anti-γ-secretase Nanobodies. These protocols could be of help in the generation of Nanobodies targeting other membrane proteins.
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Affiliation(s)
- S Veugelen
- University of Leuven, Leuven, Belgium; VIB Center for Brain and Disease, Leuven, Belgium
| | - M Dewilde
- University of Leuven, Leuven, Belgium; VIB Center for Brain and Disease, Leuven, Belgium
| | - B De Strooper
- University of Leuven, Leuven, Belgium; VIB Center for Brain and Disease, Leuven, Belgium; UCL Institute of Neurology, London, United Kingdom
| | - L Chávez-Gutiérrez
- University of Leuven, Leuven, Belgium; VIB Center for Brain and Disease, Leuven, Belgium.
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37
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The power, pitfalls and potential of the nanodisc system for NMR-based studies. Biol Chem 2016; 397:1335-1354. [DOI: 10.1515/hsz-2016-0224] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/19/2016] [Indexed: 12/21/2022]
Abstract
Abstract
The choice of a suitable membrane mimicking environment is of fundamental importance for the characterization of structure and function of membrane proteins. In this respect, usage of the lipid bilayer nanodisc technology provides a unique potential for nuclear magnetic resonance (NMR)-based studies. This review summarizes the recent advances in this field, focusing on (i) the strengths of the system, (ii) the bottlenecks that may be faced, and (iii) promising capabilities that may be explored in future studies.
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38
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Agamasu C, Ghanam RH, Xu F, Sun Y, Chen Y, Saad JS. The Interplay between Calmodulin and Membrane Interactions with the Pleckstrin Homology Domain of Akt. J Biol Chem 2016; 292:251-263. [PMID: 27872186 DOI: 10.1074/jbc.m116.752816] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/19/2016] [Indexed: 11/06/2022] Open
Abstract
The Akt protein, a serine/threonine kinase, plays important roles in cell survival, apoptosis, and oncogenes. Akt is translocated to the plasma membrane for activation. Akt-membrane binding is mediated by direct interactions between its pleckstrin homology domain (PHD) and phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3). It has been shown that Akt activation in breast cancer cells is modulated by calmodulin (CaM). However, the molecular mechanism of the interplay between CaM and membrane binding is not established. Here, we employed nuclear magnetic resonance (NMR) and biochemical and biophysical techniques to characterize how PI(3,4,5)P3, CaM, and membrane mimetics (nanodisc) bind to Akt(PHD). We show that PI(3,4,5)P3 binding to Akt(PHD) displaces the C-terminal lobe of CaM but not the weakly binding N-terminal lobe. However, binding of a PI(3,4,5)P3-embedded membrane nanodisc to Akt(PHD) with a 103-fold tighter affinity than PI(3,4,5)P3 is able to completely displace CaM. We also show that Akt(PHD) binds to both layers of the nanodisc, indicating proper incorporation of PI(3,4,5)P3 on the nanodisc surface. No detectable binding has been observed between Akt(PHD) and PI(3,4,5)P3-free nanodiscs, demonstrating that PI(3,4,5)P3 is required for membrane binding, CaM displacement, and Akt activation. Using pancreatic cancer cells, we demonstrate that inhibition of Akt-CaM binding attenuated Akt activation. Our findings support a model by which CaM binds to Akt to facilitate its translocation to the membrane. Elucidation of the molecular details of the interplay between membrane and CaM binding to Akt may help in the development of potential targets to control the pathophysiological processes of cell survival.
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Affiliation(s)
| | | | - Fei Xu
- Pathology, University of Alabama at Birmingham and
| | - Yong Sun
- Pathology, University of Alabama at Birmingham and.,the Research Department, Birmingham Veterans Affairs Medical Center, Birmingham, Alabama 35294
| | - Yabing Chen
- Pathology, University of Alabama at Birmingham and.,the Research Department, Birmingham Veterans Affairs Medical Center, Birmingham, Alabama 35294
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39
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Bagrov DV, Voskoboynikova N, Armeev GA, Mosslehy W, Gluhov GS, Ismagulova TT, Mulkidjanian AY, Kirpichnikov MP, Steinhoff HJ, Shaitan KV. Characterization of lipodisc nanoparticles containing sensory rhodopsin II and its cognate transducer from Natronomonas pharaonis. Biophysics (Nagoya-shi) 2016. [DOI: 10.1134/s0006350916060063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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40
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Simonsen JB. Evaluation of reconstituted high-density lipoprotein (rHDL) as a drug delivery platform – a detailed survey of rHDL particles ranging from biophysical properties to clinical implications. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2016; 12:2161-2179. [DOI: 10.1016/j.nano.2016.05.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 05/02/2016] [Accepted: 05/05/2016] [Indexed: 12/15/2022]
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41
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Craig AF, Clark EE, Sahu ID, Zhang R, Frantz ND, Al-Abdul-Wahid MS, Dabney-Smith C, Konkolewicz D, Lorigan GA. Tuning the size of styrene-maleic acid copolymer-lipid nanoparticles (SMALPs) using RAFT polymerization for biophysical studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2931-2939. [PMID: 27539205 DOI: 10.1016/j.bbamem.2016.08.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/15/2016] [Accepted: 08/07/2016] [Indexed: 11/29/2022]
Abstract
Characterization of membrane proteins is challenging due to the difficulty in mimicking the native lipid bilayer with properly folded and functional membrane proteins. Recently, styrene-maleic acid (StMA) copolymers have been shown to facilitate the formation of disc-like lipid bilayer mimetics that maintain the structural and dynamic integrity of membrane proteins. Here we report the controlled synthesis and characterization of StMA containing block copolymers. StMA polymers with different compositions and molecular weights were synthesized and characterized by size exclusion chromatography (SEC). These polymers act as macromolecular surfactants for 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol (POPG) lipids, forming disc like structures of the lipids with the polymer wrapping around the hydrophobic lipid edge. A combination of dynamic light scattering (DLS), solid-state nuclear magnetic resonance (SSNMR) spectroscopy, and transmission electron microscopy (TEM) was used to characterize the size of the nanoparticles created using these StMA polymers. At a weight ratio of 1.25:1 StMA to lipid, the nanoparticle size created is 28+1nm for a 2:1 ratio, 10+1nm for a 3:1 StMA ratio and 32+1nm for a 4:1 StMA ratio independent of the molecular weight of the polymer. Due to the polymer acting as a surfactant that forms disc like nanoparticles, we term these StMA based block copolymers "RAFT SMALPs". RAFT SMALPs show promise as a new membrane mimetic with different nanoscale sizes, which can be used for a wide variety of biophysical studies of membrane proteins.
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Affiliation(s)
- Andrew F Craig
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States
| | - Emily E Clark
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States
| | - Indra D Sahu
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States
| | - Rongfu Zhang
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States
| | - Nick D Frantz
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States
| | - M Sameer Al-Abdul-Wahid
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States
| | - Carole Dabney-Smith
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States
| | - Dominik Konkolewicz
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States.
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42
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Henke K, Welte W, Hauser K. Direct Monitoring of β-Sheet Formation in the Outer Membrane Protein TtoA Assisted by TtOmp85. Biochemistry 2016; 55:4333-43. [PMID: 27400268 DOI: 10.1021/acs.biochem.6b00691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was applied to investigate the folding of an outer membrane protein, TtoA, assisted by TtOmp85, both from the thermophilic eubacterium Thermus thermophilus. To directly monitor the formation of β-sheet structure in TtoA and to analyze the function of TtOmp85, we immobilized unfolded TtoA on an ATR crystal. Interaction with TtOmp85 initiated TtoA folding as shown by time-dependent spectra recorded during the folding process. Our ATR-FTIR experiments prove that TtOmp85 possesses specific functionality to assist β-sheet formation of TtoA. We demonstrate the potential of this spectroscopic approach to study the interaction of outer membrane proteins in vitro and in a time-resolved manner.
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Affiliation(s)
- Katharina Henke
- Department of Chemistry, ‡Department of Biology, and §Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
| | - Wolfram Welte
- Department of Chemistry, ‡Department of Biology, and §Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
| | - Karin Hauser
- Department of Chemistry, ‡Department of Biology, and §Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
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43
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Artificial membranes for membrane protein purification, functionality and structure studies. Biochem Soc Trans 2016; 44:877-82. [DOI: 10.1042/bst20160054] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Indexed: 11/17/2022]
Abstract
Membrane proteins represent one of the most important targets for pharmaceutical companies. Unfortunately, technical limitations have long been a major hindrance in our understanding of the function and structure of such proteins. Recent years have seen the refinement of classical approaches and the emergence of new technologies that have resulted in a significant step forward in the field of membrane protein research. This review summarizes some of the current techniques used for studying membrane proteins, with overall advantages and drawbacks for each method.
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44
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Natali A, Gruber JM, Dietzel L, Stuart MCA, van Grondelle R, Croce R. Light-harvesting Complexes (LHCs) Cluster Spontaneously in Membrane Environment Leading to Shortening of Their Excited State Lifetimes. J Biol Chem 2016; 291:16730-9. [PMID: 27252376 DOI: 10.1074/jbc.m116.730101] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Indexed: 11/06/2022] Open
Abstract
The light reactions of photosynthesis, which include light-harvesting and charge separation, take place in the amphiphilic environment of the thylakoid membrane. The light-harvesting complex II (LHCII) is the main responsible for light absorption in plants and green algae and is involved in photoprotective mechanisms that regulate the amount of excited states in the membrane. The dual function of LHCII has been extensively studied in detergent micelles, but recent results have indicated that the properties of this complex differ in a lipid environment. In this work we checked these suggestions by studying LHCII in liposomes. By combining bulk and single molecule measurements, we monitored the fluorescence characteristics of liposomes containing single complexes up to densely packed proteoliposomes. We show that the natural lipid environment per se does not alter the properties of LHCII, which for single complexes remain very similar to that in detergent. However, we show that LHCII has the strong tendency to cluster in the membrane and that protein interactions and the extent of crowding modulate the lifetimes of the excited state in the membrane. Finally, the presence of LHCII monomers at low concentrations of complexes per liposome is discussed.
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Affiliation(s)
- Alberto Natali
- From the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - J Michael Gruber
- From the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Lars Dietzel
- Institute of Molecular Biosciences, Goethe-University Frankfurt/M, 60438 Frankfurt, Germany, and
| | - Marc C A Stuart
- Electron Microscopy, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Rienk van Grondelle
- From the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Roberta Croce
- From the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, 1081 HV Amsterdam, The Netherlands,
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45
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Bajaj R, Bruce KE, Davidson AL, Rued BE, Stauffacher CV, Winkler ME. Biochemical characterization of essential cell division proteins FtsX and FtsE that mediate peptidoglycan hydrolysis by PcsB in Streptococcus pneumoniae. Microbiologyopen 2016; 5:738-752. [PMID: 27167971 PMCID: PMC5061712 DOI: 10.1002/mbo3.366] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 03/14/2016] [Accepted: 03/23/2016] [Indexed: 01/02/2023] Open
Abstract
The FtsEX:PcsB complex forms a molecular machine that carries out peptidoglycan (PG) hydrolysis during normal cell division of the major respiratory pathogenic bacterium, Streptococcus pneumoniae (pneumococcus). FtsX is an integral membrane protein and FtsE is a cytoplasmic ATPase that together structurally resemble ABC transporters. Instead of transport, FtsEX transduces signals from the cell division apparatus to stimulate PG hydrolysis by PcsB, which interacts with extracellular domains of FtsX. Structural studies of PcsB and one extracellular domain of FtsX have recently appeared, but little is known about the biochemical properties of the FtsE ATPase or the intact FtsX transducer protein. We report here purifications and characterizations of tagged FtsX and FtsE proteins. Pneumococcal FtsX‐GFP‐His and FtsX‐His could be overexpressed in Escherichia coli without toxicity, and FtsE‐His remained soluble during purification. FtsX‐His dimerizes in detergent micelles and when reconstituted in phospholipid nanodiscs. FtsE‐His binds an ATP analog with an affinity comparable to that of ATPase subunits of ABC transporters, and FtsE‐His preparations have a low, detectable ATPase activity. However, attempts to detect complexes of purified FtsX‐His, FtsE‐His, and PcsB‐His or coexpressed tagged FtsX and FtsE were not successful with the constructs and conditions tested so far. In working with nanodiscs, we found that PcsB‐His has an affinity for charged phospholipids, mediated partly by interactions with its coiled‐coil domain. Together, these findings represent first steps toward reconstituting the FtsEX:PcsB complex biochemically and provide information that may be relevant to the assembly of the complex on the surface of pneumococcal cells.
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Affiliation(s)
- Ruchika Bajaj
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, 47907
| | - Kevin E Bruce
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, 47405
| | - Amy L Davidson
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, 47907
| | - Britta E Rued
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, 47405
| | - Cynthia V Stauffacher
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, 47907
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, 47405.
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46
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Li B, Makino SI, Beebe ET, Urano D, Aceti DJ, Misenheimer TM, Peters J, Fox BG, Jones AM. Cell-free translation and purification of Arabidopsis thaliana regulator of G signaling 1 protein. Protein Expr Purif 2016; 126:33-41. [PMID: 27164033 DOI: 10.1016/j.pep.2016.04.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 04/12/2016] [Accepted: 04/28/2016] [Indexed: 01/21/2023]
Abstract
Arabidopsis thaliana Regulator of G protein Signalling 1 (AtRGS1) is a protein with a predicted N-terminal 7-transmembrane (7TM) domain and a C-terminal cytosolic RGS1 box domain. The RGS1 box domain exerts GTPase activation (GAP) activity on Gα (AtGPA1), a component of heterotrimeric G protein signaling in plants. AtRGS1 may perceive an exogenous agonist to regulate the steady-state levels of the active form of AtGPA1. It is uncertain if the full-length AtRGS1 protein exerts any atypical effects on Gα, nor has it been established exactly how AtRGS1 contributes to perception of an extracellular signal and transmits this response to a G-protein dependent signaling cascade. Further studies on full-length AtRGS1 have been inhibited due to the extreme low abundance of the endogenous AtRGS1 protein in plants and lack of a suitable heterologous system to express AtRGS1. Here, we describe methods to produce full-length AtRGS1 by cell-free synthesis into unilamellar liposomes and nanodiscs. The cell-free synthesized AtRGS1 exhibits GTPase activating activity on Gα and can be purified to a level suitable for biochemical analyses.
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Affiliation(s)
- Bo Li
- Department of Biology, University of North Carolina at Chapel Hill, United States
| | - Shin-Ichi Makino
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Emily T Beebe
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Daisuke Urano
- Department of Biology, University of North Carolina at Chapel Hill, United States
| | - David J Aceti
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Tina M Misenheimer
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Jonathan Peters
- Department of Biology, University of North Carolina at Chapel Hill, United States
| | - Brian G Fox
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Alan M Jones
- Department of Biology, University of North Carolina at Chapel Hill, United States; Department of Pharmacology, University of North Carolina at Chapel Hill, United States.
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47
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Legrand F, Breyton C, Guillet P, Ebel C, Durand G. Hybrid Fluorinated and Hydrogenated Double-Chain Surfactants for Handling Membrane Proteins. J Org Chem 2016; 81:681-8. [PMID: 26694765 DOI: 10.1021/acs.joc.5b02137] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two hybrid fluorinated double-chain surfactants with a diglucosylated polar head were synthesized. The apolar domain consists of a perfluorohexyl main chain and a butyl hydrogenated branch as a side chain. They were found to self-assemble into small micelles at low critical micellar concentrations, demonstrating that the short branch increases the overall hydrophobicity while keeping the length of the apolar domain short. They were both able to keep the membrane protein bacteriorhodopsin stable, one of them for at least 3 months.
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Affiliation(s)
- Fréderic Legrand
- Institut des Biomolécules Max Mousseron UMR 5247 CNRS-Université Montpellier-ENSCM & Avignon Université , Equipe Chimie Bioorganique et Systèmes Amphiphiles, 301 rue Baruch de Spinoza BP 21239, 84916 Cedex 9 Avignon, France
| | - Cécile Breyton
- Université Grenoble Alpes, IBS , F-38044 Grenoble, France.,CNRS, IBS , F-38044 Grenoble, France.,CEA, IBS , F-38044 Grenoble, France
| | - Pierre Guillet
- Institut des Biomolécules Max Mousseron UMR 5247 CNRS-Université Montpellier-ENSCM & Avignon Université , Equipe Chimie Bioorganique et Systèmes Amphiphiles, 301 rue Baruch de Spinoza BP 21239, 84916 Cedex 9 Avignon, France
| | - Christine Ebel
- Université Grenoble Alpes, IBS , F-38044 Grenoble, France.,CNRS, IBS , F-38044 Grenoble, France.,CEA, IBS , F-38044 Grenoble, France
| | - Grégory Durand
- Institut des Biomolécules Max Mousseron UMR 5247 CNRS-Université Montpellier-ENSCM & Avignon Université , Equipe Chimie Bioorganique et Systèmes Amphiphiles, 301 rue Baruch de Spinoza BP 21239, 84916 Cedex 9 Avignon, France
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48
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Moses M, Hedegård P, Hatzakis N. Quantification of Functional Dynamics of Membrane Proteins Reconstituted in Nanodiscs Membranes by Single Turnover Functional Readout. Methods Enzymol 2016; 581:227-256. [DOI: 10.1016/bs.mie.2016.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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49
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Dominik PK, Borowska MT, Dalmas O, Kim SS, Perozo E, Keenan RJ, Kossiakoff AA. Conformational Chaperones for Structural Studies of Membrane Proteins Using Antibody Phage Display with Nanodiscs. Structure 2015; 24:300-9. [PMID: 26749445 DOI: 10.1016/j.str.2015.11.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/20/2015] [Accepted: 11/23/2015] [Indexed: 01/18/2023]
Abstract
A major challenge in membrane biophysics is to define the mechanistic linkages between a protein's conformational transitions and its function. We describe a novel approach to stabilize transient functional states of membrane proteins in native-like lipid environments allowing for their structural and biochemical characterization. This is accomplished by combining the power of antibody Fab-based phage display selection with the benefits of embedding membrane protein targets in lipid-filled nanodiscs. In addition to providing a stabilizing lipid environment, nanodiscs afford significant technical advantages over detergent-based formats. This enables the production of a rich pool of high-performance Fab binders that can be used as crystallization chaperones, as fiducial markers for single-particle cryoelectron microscopy, and as probes of different conformational states. Moreover, nanodisc-generated Fabs can be used to identify detergents that best mimic native membrane environments for use in biophysical studies.
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Affiliation(s)
- Pawel K Dominik
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Marta T Borowska
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Olivier Dalmas
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Sangwoo S Kim
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Eduardo Perozo
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Robert J Keenan
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
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50
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Tu Y, Peng F, Adawy A, Men Y, Abdelmohsen LKEA, Wilson DA. Mimicking the Cell: Bio-Inspired Functions of Supramolecular Assemblies. Chem Rev 2015; 116:2023-78. [DOI: 10.1021/acs.chemrev.5b00344] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Yingfeng Tu
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Fei Peng
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Alaa Adawy
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Yongjun Men
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Loai K. E. A. Abdelmohsen
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Daniela A. Wilson
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
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