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Iannotta D, A A, Lai A, Nair S, Koifman N, Lappas M, Salomon C, Wolfram J. Chemically-Induced Lipoprotein Breakdown for Improved Extracellular Vesicle Purification. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2307240. [PMID: 38100284 DOI: 10.1002/smll.202307240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/08/2023] [Indexed: 12/17/2023]
Abstract
Extracellular vesicles (EVs) are nanosized biomolecular packages involved in intercellular communication. EVs are released by all cells, making them broadly applicable as therapeutic, diagnostic, and mechanistic components in (patho)physiology. Sample purity is critical for correctly attributing observed effects to EVs and for maximizing therapeutic and diagnostic performance. Lipoprotein contaminants represent a major challenge for sample purity. Lipoproteins are approximately six orders of magnitude more abundant in the blood circulation and overlap in size, shape, and density with EVs. This study represents the first example of an EV purification method based on the chemically-induced breakdown of lipoproteins. Specifically, a styrene-maleic acid (SMA) copolymer is used to selectively breakdown lipoproteins, enabling subsequent size-based separation of the breakdown products from plasma EVs. The use of the polymer followed by tangential flow filtration or size-exclusion chromatography results in improved EV yield, preservation of EV morphology, increased EV markers, and reduced contaminant markers. SMA-based EV purification enables improved fluorescent labeling, reduces interactions with macrophages, and enhances accuracy, sensitivity, and specificity to detect EV biomarkers, indicating benefits for various downstream applications. In conclusion, SMA is a simple and effective method to improve the purity and yield of plasma-derived EVs, which favorably impacts downstream applications.
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Affiliation(s)
- Dalila Iannotta
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Amruta A
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Andrew Lai
- Translational Extracellular Vesicles in Obstetrics and Gynae-Oncology Group, Faculty of Medicine, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
| | - Soumyalekshmi Nair
- Translational Extracellular Vesicles in Obstetrics and Gynae-Oncology Group, Faculty of Medicine, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
| | - Na'ama Koifman
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Martha Lappas
- University of Melbourne, Department of Obstetrics and Gynaecology, Australia, and Mercy Hospital for Women, 163 Studley Road, Heidelberg, Victoria, 3084, Australia
| | - Carlos Salomon
- Translational Extracellular Vesicles in Obstetrics and Gynae-Oncology Group, Faculty of Medicine, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
| | - Joy Wolfram
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, 4072, Australia
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, 77030, USA
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Krajewska M, Możajew M, Filipek S, Koprowski P. Interaction of ROMK2 channel with lipid kinases DGKE and AGK: Potential channel activation by localized anionic lipid synthesis. Biochim Biophys Acta Mol Cell Biol Lipids 2024; 1869:159443. [PMID: 38056763 DOI: 10.1016/j.bbalip.2023.159443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/20/2023] [Accepted: 11/30/2023] [Indexed: 12/08/2023]
Abstract
In this study, we utilized enzyme-catalyzed proximity labeling with the engineered promiscuous biotin ligase Turbo-ID to identify the proxisome of the ROMK2 channel. This channel resides in various cellular membrane compartments of the cell including the plasma membrane, endoplasmic reticulum and mitochondria. Within mitochondria, ROMK2 has been suggested as a pore-forming subunit of mitochondrial ATP-regulated potassium channel (mitoKATP). We found that ROMK2 proxisome in addition to previously known protein partners included two lipid kinases: acylglycerol kinase (AGK) and diacylglycerol kinase ε (DGKE), which are localized in mitochondria and the endoplasmic reticulum, respectively. Through co-immunoprecipitation, we confirmed that these two kinases are present in complexes with ROMK2 channels. Additionally, we found that the products of AGK and DGKE, lysophosphatidic acid (LPA) and phosphatidic acid (PA), stimulated the activity of ROMK2 channels in artificial lipid bilayers. Our molecular docking studies revealed the presence of acidic lipid binding sites in the ROMK2 channel, similar to those previously identified in Kir2 channels. Based on these findings, we propose a model wherein localized lipid synthesis, mediated by channel-bound lipid kinases, contributes to the regulation of ROMK2 activity within distinct intracellular compartments, such as mitochondria and the endoplasmic reticulum.
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Affiliation(s)
- Milena Krajewska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, Warsaw, Poland
| | - Mariusz Możajew
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, Warsaw, Poland; Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Sławomir Filipek
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Piotr Koprowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, Warsaw, Poland.
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3
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Krishnarjuna B, Sharma G, Ravula T, Ramamoorthy A. Factors influencing the detergent-free membrane protein isolation using synthetic nanodisc-forming polymers. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184240. [PMID: 37866688 DOI: 10.1016/j.bbamem.2023.184240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 10/08/2023] [Accepted: 10/17/2023] [Indexed: 10/24/2023]
Abstract
The detergent-free isolation of membrane proteins using synthetic polymers is becoming the desired approach for functional and structural studies of membrane proteins. Since the expression levels for many membrane proteins are low and a high yield of functionalized reconstituted membrane proteins is essential for in vitro studies, it is crucial to optimize the experimental conditions for a given polymer to solubilize target membranes/proteins effectively. The factors that affect membrane solubilization and subsequently the isolation of a target membrane protein include polymer concentration, polymer charge, temperature, pH, and concentration of divalent metal ions. Therefore, it is important to have knowledge about the efficacy of different types of polymers in solubilizing cell membranes. In this study, we evaluate the efficacy of inulin-based non-ionic polymers in solubilizing E. coli membranes enriched with rat flavin mononucleotide binding-domain (FBD) of cytochrome-P450-reductase (CPR) and rabbit cytochrome-b5 (Cyt-b5) under various solubilization conditions. Our results show that a 1:1 (w/w) membrane:polymer ratio, low temperature, high pH and sub-millimolar concentration of metal ions favor the solubilization of E. coli membranes enriched with FBD or Cyt-b5. Conversely, the presence of excess divalent metal ions affected the final protein levels in the polymer-solubilized samples. We believe that the results from this study provide knowledge to assess and plan the use of non-ionic polymers in membrane protein studies.
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Affiliation(s)
- Bankala Krishnarjuna
- Biophysics Program, Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Gaurav Sharma
- Biophysics Program, Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Thirupathi Ravula
- Biophysics Program, Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Ayyalusamy Ramamoorthy
- National High Magnetic Field Laboratory, Department of Chemical and Biomedical Engineering, Florida State University, Tallahassee, FL 32310, USA.
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4
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Scheyer MW, Campbell C, William PL, Hussain M, Begum A, Fonseca SE, Asare IK, Dabney P, Dabney-Smith C, Lorigan GA, Sahu ID. Electron paramagnetic resonance spectroscopic characterization of the human KCNE3 protein in lipodisq nanoparticles for structural dynamics of membrane proteins. Biophys Chem 2023; 301:107080. [PMID: 37531799 DOI: 10.1016/j.bpc.2023.107080] [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: 05/25/2023] [Revised: 07/07/2023] [Accepted: 07/24/2023] [Indexed: 08/04/2023]
Abstract
One of the major challenges in solubilization of membrane proteins is to find the optimal physiological environment for their biophysical studies. EPR spectroscopy is a powerful biophysical technique for studying the structural and dynamic properties of macromolecules. However, the challenges in the membrane protein sample preparation and flexible motion of the spin label limit the utilization of EPR spectroscopy to a majority of membrane protein systems in a physiological membrane-bound state. Recently, lipodisq nanoparticles or styrene-maleic acid copolymer-lipid nanoparticles (SMALPs) have emerged as a membrane mimetic system for investigating the structural studies of membrane proteins. However, its detail characterization for membrane protein studies is still poorly understood. Recently, we characterized the potassium channel membrane protein KCNQ1 voltage sensing domain (KCNQ1-VSD) and KCNE1 reconstituted into lipodisq nanoparticles using EPR spectroscopy. In this study, the potassium channel accessory protein KCNE3 containing flexible N- and C-termini was encapsulated into proteoliposomes and lipodisq nanoparticles and characterized for studying its structural and dynamic properties using nitroxide based site-directed spin labeling EPR spectroscopy. CW-EPR lineshape analysis data indicated an increase in spectral line broadenings with the addition of the styrene-maleic acid (SMA) polymer which approaches close to the rigid limit providing a homogeneous stabilization of the protein-lipid complex. Similarly, EPR DEER measurements indicated an enhanced quality of distance measurements with an increase in the phase memory time (Tm) values upon incorporation of the sample into lipodisq nanoparticles, when compared to proteoliposomes. These results agree with the solution NMR structural structure of the KCNE3 and EPR studies of other membrane proteins in lipodisq nanoparticles. This study along with our earlier studies will provide the reference characterization data that will provide benefit to the membrane protein researchers for studying structural dynamics of challenging membrane proteins.
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Affiliation(s)
- Matthew W Scheyer
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Conner Campbell
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Patrick L William
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Mustakim Hussain
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Afsana Begum
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | | | - Isaac K Asare
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Peyton Dabney
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA
| | - Carole Dabney-Smith
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Indra D Sahu
- Natural Science Division, Campbellsville University, Campbellsville, KY 42718, USA; Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA.
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5
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Zhou R, Zhang S, Nguyen HT, Ding H, Gaffney A, Kappes JC, Smith AB, Sodroski JG. Conformations of Human Immunodeficiency Virus Envelope Glycoproteins in Detergents and Styrene-Maleic Acid Lipid Particles. J Virol 2023; 97:e0032723. [PMID: 37255444 PMCID: PMC10308955 DOI: 10.1128/jvi.00327-23] [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: 02/28/2023] [Accepted: 05/10/2023] [Indexed: 06/01/2023] Open
Abstract
The mature human immunodeficiency virus (HIV) envelope glycoprotein (Env) trimer, which consists of noncovalently associated gp120 exterior and gp41 transmembrane subunits, mediates virus entry into cells. The pretriggered (State-1) Env conformation is the major target for broadly neutralizing antibodies (bNAbs), whereas receptor-induced downstream Env conformations elicit immunodominant, poorly neutralizing antibody (pNAb) responses. To examine the contribution of membrane anchorage to the maintenance of the metastable pretriggered Env conformation, we compared wild-type and State-1-stabilized Envs solubilized in detergents or in styrene-maleic acid (SMA) copolymers. SMA directly incorporates membrane lipids and resident membrane proteins into lipid nanoparticles (styrene-maleic acid lipid particles [SMALPs]). The integrity of the Env trimer in SMALPs was maintained at both 4°C and room temperature. In contrast, Envs solubilized in Cymal-5, a nonionic detergent, were unstable at room temperature, although their stability was improved at 4°C and/or after incubation with the entry inhibitor BMS-806. Envs solubilized in ionic detergents were relatively unstable at either temperature. Comparison of Envs solubilized in Cymal-5 and SMA at 4°C revealed subtle differences in bNAb binding to the gp41 membrane-proximal external region, consistent with these distinct modes of Env solubilization. Otherwise, the antigenicity of the Cymal-5- and SMA-solubilized Envs was remarkably similar, both in the absence and in the presence of BMS-806. However, both solubilized Envs were recognized differently from the mature membrane Env by specific bNAbs and pNAbs. Thus, detergent-based and detergent-free solubilization at 4°C alters the pretriggered membrane Env conformation in consistent ways, suggesting that Env assumes default conformations when its association with the membrane is disrupted. IMPORTANCE The human immunodeficiency virus (HIV) envelope glycoproteins (Envs) in the viral membrane mediate virus entry into the host cell and are targeted by neutralizing antibodies elicited by natural infection or vaccines. Detailed studies of membrane proteins rely on purification procedures that allow the proteins to maintain their natural conformation. In this study, we show that a styrene-maleic acid (SMA) copolymer can extract HIV-1 Env from a membrane without the use of detergents. The Env in SMA is more stable at room temperature than Env in detergents. The purified Env in SMA maintains many but not all of the characteristics expected of the natural membrane Env. Our results underscore the importance of the membrane environment to the native conformation of HIV-1 Env. Purification methods that bypass the need for detergents could be useful tools for future studies of HIV-1 Env structure and its interaction with receptors and antibodies.
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Affiliation(s)
- Rong Zhou
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Shijian Zhang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Hanh T. Nguyen
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Haitao Ding
- Department of Medicine, University of Alabama at Birmingham, Alabama, USA
- Birmingham Veterans Affairs Medical Center, Research Service, Birmingham, Alabama, USA
| | - Althea Gaffney
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John C. Kappes
- Department of Medicine, University of Alabama at Birmingham, Alabama, USA
- Birmingham Veterans Affairs Medical Center, Research Service, Birmingham, Alabama, USA
| | - Amos B. Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Joseph G. Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
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6
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Zhou Y, Syed JH, Semchonok DA, Wright E, Kyrilis FL, Hamdi F, Kastritis PL, Bruce BD, Reynolds TB. Solubilization, purification, and characterization of the hexameric form of phosphatidylserine synthase from Candida albicans. J Biol Chem 2023:104756. [PMID: 37116705 DOI: 10.1016/j.jbc.2023.104756] [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: 12/16/2022] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 04/30/2023] Open
Abstract
Phosphatidylserine (PS) synthase from Candida albicans, encoded by the CHO1 gene, has been identified as a potential drug target for new antifungals against systemic candidiasis. Rational drug design or small molecule screening are effective ways to identify specific inhibitors of Cho1, but both will be facilitated by protein purification. Due to the transmembrane nature of Cho1, methods were needed to solubilize and purify the native form of Cho1. Here, we used six non-ionic detergents and three styrene maleic acids (SMAs) to solubilize an HA-tagged Cho1 protein from the total microsomal fractions. Blue native PAGE (BN-PAGE) and immunoblot analysis revealed a single band corresponding to Cho1 in all detergent-solubilized fractions, while two bands were present in the SMA2000-solubilized fraction. Our enzymatic assay suggests that digitonin- or DDM-solubilized enzyme has the most PS synthase activity. Pull-downs of HA-tagged Cho1 in the digitonin-solubilized fraction reveal an apparent MW of Cho1 consistent with a hexamer. Furthermore, negative-staining electron microscopy analysis and AlphaFold2 structure prediction modeling suggest the hexamer is composed of a trimer of dimers. We purified Cho1 protein to near-homogeneity as a hexamer using affinity chromatography and TEV protease treatment, and optimized Cho1 enzyme activity for manganese and detergent concentrations, temperature (24°C), and pH (8.0). The purified Cho1 has a Km for its substrate CDP-diacylglycerol of 72.20 μM with a Vmax of 0.079 nmol/(μg*min) while exhibiting a sigmoidal kinetic curve for its other substrate serine, indicating cooperative binding. Purified hexameric Cho1 can potentially be used in downstream structure determination and small drug screening.
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Affiliation(s)
- Yue Zhou
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, TN, United States
| | - Jawhar H Syed
- Department of Biochemistry Cellular and Molecular Biology, University of Tennessee Knoxville, Knoxville, TN, United States
| | - Dmitry A Semchonok
- Interdisciplinary Research Center HALOmem & Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Edward Wright
- Department of Biochemistry Cellular and Molecular Biology, University of Tennessee Knoxville, Knoxville, TN, United States
| | - Fotis L Kyrilis
- Interdisciplinary Research Center HALOmem & Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Farzad Hamdi
- Interdisciplinary Research Center HALOmem & Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem & Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Barry D Bruce
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, TN, United States; Department of Biochemistry Cellular and Molecular Biology, University of Tennessee Knoxville, Knoxville, TN, United States
| | - Todd B Reynolds
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, TN, United States
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Sinha S, Kumar S, Singh K, Umam F, Agrawal V, Aggarwal A, Imperiali B. Immunochemical characterisation of styrene maleic acid lipid particles prepared from Mycobacterium tuberculosis plasma membrane. PLoS One 2023; 18:e0280074. [PMID: 36608027 PMCID: PMC9821473 DOI: 10.1371/journal.pone.0280074] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 12/20/2022] [Indexed: 01/07/2023] Open
Abstract
Membrane proteins of Mycobacterium tuberculosis (Mtb) can be targeted for the development of therapeutic and prophylactic interventions against tuberculosis. We have utilized the unique membrane-solubilising properties of the styrene maleic acid copolymer <styrene:maleic acid::2:1> (SMA) to prepare and characterise 'styrene maleic acid lipid particles' from the native membrane of Mtb (MtM-SMALPs). When resolved by SDS-PAGE and visualised with coomassie blue, the molecular weights of Mtb membrane (MtM) proteins solubilised by SMA were mostly in the range of 40-70 kDa. When visualised by transmission electron microscopy, MtM-SMALPs appeared as nanoparticles of discrete shapes and sizes. The discoid nanoparticles exhibited a range of diameters of ~10-90 nm, with largest portion (~61%) ranging from 20-40 nm. MtM proteins of a molecular weight-range overlapping with that of MtM-SMALPs were also amenable to chemical cross-linking, revealing protein complex formation. Characterisation using monoclonal antibodies against seven MtM-associated antigens confirmed the incorporation of the inner membrane protein PRA, membrane-associated proteins PstS1, LpqH and Ag85, and the lipoglycan LAM into MtM-SMALPs. Conversely, the peripheral membrane proteins Acr and PspA were nearly completely excluded. Furthermore, although MtM showed an abundance of Con A-binding glycoproteins, MtM-SMALPs appeared devoid of these species. Immune responses of healthcare workers harbouring 'latent TB infection' provided additional insights. While MtM-SMALPs and MtM induced comparable levels of the cytokine IFN-γ, only MtM-SMALPs could induce the production of TNF-α. Antibodies present in the donor sera showed significantly higher binding to MtM than to MtM-SMALPs. These results have implications for the development of MtM-based immunoprophylaxis against tuberculosis.
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Affiliation(s)
- Sudhir Sinha
- Department of Clinical Immunology & Rheumatology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
- * E-mail:
| | - Shashikant Kumar
- Department of Clinical Immunology & Rheumatology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Komal Singh
- Department of Clinical Immunology & Rheumatology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Fareha Umam
- Department of Clinical Immunology & Rheumatology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Vinita Agrawal
- Department of Pathology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Amita Aggarwal
- Department of Clinical Immunology & Rheumatology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Barbara Imperiali
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
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8
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Krishnarjuna B, Ramamoorthy A. Detergent-Free Isolation of Membrane Proteins and Strategies to Study Them in a Near-Native Membrane Environment. Biomolecules 2022; 12:1076. [PMID: 36008970 PMCID: PMC9406181 DOI: 10.3390/biom12081076] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 07/31/2022] [Accepted: 08/02/2022] [Indexed: 02/06/2023] Open
Abstract
Atomic-resolution structural studies of membrane-associated proteins and peptides in a membrane environment are important to fully understand their biological function and the roles played by them in the pathology of many diseases. However, the complexity of the cell membrane has severely limited the application of commonly used biophysical and biochemical techniques. Recent advancements in NMR spectroscopy and cryoEM approaches and the development of novel membrane mimetics have overcome some of the major challenges in this area. For example, the development of a variety of lipid-nanodiscs has enabled stable reconstitution and structural and functional studies of membrane proteins. In particular, the ability of synthetic amphipathic polymers to isolate membrane proteins directly from the cell membrane, along with the associated membrane components such as lipids, without the use of a detergent, has opened new avenues to study the structure and function of membrane proteins using a variety of biophysical and biological approaches. This review article is focused on covering the various polymers and approaches developed and their applications for the functional reconstitution and structural investigation of membrane proteins. The unique advantages and limitations of the use of synthetic polymers are also discussed.
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Affiliation(s)
- Bankala Krishnarjuna
- Department of Chemistry and Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry and Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
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9
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Laurence MJ, Carpenter TS, Laurence TA, Coleman MA, Shelby M, Liu C. Biophysical Characterization of Membrane Proteins Embedded in Nanodiscs Using Fluorescence Correlation Spectroscopy. MEMBRANES 2022; 12:membranes12040392. [PMID: 35448362 PMCID: PMC9028781 DOI: 10.3390/membranes12040392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 02/04/2023]
Abstract
Proteins embedded in biological membranes perform essential functions in all organisms, serving as receptors, transporters, channels, cell adhesion molecules, and other supporting cellular roles. These membrane proteins comprise ~30% of all human proteins and are the targets of ~60% of FDA-approved drugs, yet their extensive characterization using established biochemical and biophysical methods has continued to be elusive due to challenges associated with the purification of these insoluble proteins. In response, the development of nanodisc techniques, such as nanolipoprotein particles (NLPs) and styrene maleic acid polymers (SMALPs), allowed membrane proteins to be expressed and isolated in solution as part of lipid bilayer rafts with defined, consistent nanometer sizes and compositions, thus enabling solution-based measurements. Fluorescence correlation spectroscopy (FCS) is a relatively simple yet powerful optical microscopy-based technique that yields quantitative biophysical information, such as diffusion kinetics and concentrations, about individual or interacting species in solution. Here, we first summarize current nanodisc techniques and FCS fundamentals. We then provide a focused review of studies that employed FCS in combination with nanodisc technology to investigate a handful of membrane proteins, including bacteriorhodopsin, bacterial division protein ZipA, bacterial membrane insertases SecYEG and YidC, Yersinia pestis type III secretion protein YopB, yeast cell wall stress sensor Wsc1, epidermal growth factor receptor (EGFR), ABC transporters, and several G protein-coupled receptors (GPCRs).
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Affiliation(s)
- Matthew J. Laurence
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
| | - Timothy S. Carpenter
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
| | - Ted A. Laurence
- Materials Science Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA;
| | - Matthew A. Coleman
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
- Department of Radiation Oncology, University of California Davis, Sacramento, CA 95616, USA
| | - Megan Shelby
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
- Correspondence: (M.S.); (C.L.)
| | - Chao Liu
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
- Correspondence: (M.S.); (C.L.)
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10
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Orekhov PS, Bozdaganyan ME, Voskoboynikova N, Mulkidjanian AY, Karlova MG, Yudenko A, Remeeva A, Ryzhykau YL, Gushchin I, Gordeliy VI, Sokolova OS, Steinhoff HJ, Kirpichnikov MP, Shaitan KV. Mechanisms of Formation, Structure, and Dynamics of Lipoprotein Discs Stabilized by Amphiphilic Copolymers: A Comprehensive Review. NANOMATERIALS 2022; 12:nano12030361. [PMID: 35159706 PMCID: PMC8838559 DOI: 10.3390/nano12030361] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 01/15/2022] [Accepted: 01/20/2022] [Indexed: 12/16/2022]
Abstract
Amphiphilic copolymers consisting of alternating hydrophilic and hydrophobic units account for a major recent methodical breakthrough in the investigations of membrane proteins. Styrene–maleic acid (SMA), diisobutylene–maleic acid (DIBMA), and related copolymers have been shown to extract membrane proteins directly from lipid membranes without the need for classical detergents. Within the particular experimental setup, they form disc-shaped nanoparticles with a narrow size distribution, which serve as a suitable platform for diverse kinds of spectroscopy and other biophysical techniques that require relatively small, homogeneous, water-soluble particles of separate membrane proteins in their native lipid environment. In recent years, copolymer-encased nanolipoparticles have been proven as suitable protein carriers for various structural biology applications, including cryo-electron microscopy (cryo-EM), small-angle scattering, and conventional and single-molecule X-ray diffraction experiments. Here, we review the current understanding of how such nanolipoparticles are formed and organized at the molecular level with an emphasis on their chemical diversity and factors affecting their size and solubilization efficiency.
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Affiliation(s)
- Philipp S. Orekhov
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Faculty of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China
- Institute of Personalized Medicine, Sechenov University, 119146 Moscow, Russia
- Correspondence: (P.S.O.); (K.V.S.)
| | - Marine E. Bozdaganyan
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Faculty of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Natalia Voskoboynikova
- Department of Physics, University of Osnabrück, Barbarastrasse 7, 49076 Osnabrück, Germany; (N.V.); (A.Y.M.); (H.-J.S.)
| | - Armen Y. Mulkidjanian
- Department of Physics, University of Osnabrück, Barbarastrasse 7, 49076 Osnabrück, Germany; (N.V.); (A.Y.M.); (H.-J.S.)
- Faculty of Bioengineering and Bioinformatics and Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Maria G. Karlova
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
| | - Anna Yudenko
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
| | - Alina Remeeva
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
| | - Yury L. Ryzhykau
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
| | - Ivan Gushchin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
| | - Valentin I. Gordeliy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia; (A.Y.); (A.R.); (Y.L.R.); (I.G.); (V.I.G.)
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, 52428 Jülich, Germany
- Institut de Biologie Structurale J.-P. Ebel, Université Grenoble Alpes-CEA-CNRS, 38000 Grenoble, France
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Olga S. Sokolova
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Faculty of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China
| | - Heinz-Jürgen Steinhoff
- Department of Physics, University of Osnabrück, Barbarastrasse 7, 49076 Osnabrück, Germany; (N.V.); (A.Y.M.); (H.-J.S.)
| | - Mikhail P. Kirpichnikov
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Konstantin V. Shaitan
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (M.E.B.); (M.G.K.); (O.S.S.); (M.P.K.)
- Correspondence: (P.S.O.); (K.V.S.)
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Abstract
The SARS-CoV-2 coronavirus, the etiologic agent of COVID-19, uses its spike (S) glycoprotein anchored in the viral membrane to enter host cells. The S glycoprotein is the major target for neutralizing antibodies elicited by natural infection and by vaccines. Approximately 35% of the SARS-CoV-2 S glycoprotein consists of carbohydrate, which can influence virus infectivity and susceptibility to antibody inhibition. We found that virus-like particles produced by coexpression of SARS-CoV-2 S, M, E, and N proteins contained spike glycoproteins that were extensively modified by complex carbohydrates. We used a fucose-selective lectin to purify the Golgi-modified fraction of a wild-type SARS-CoV-2 S glycoprotein trimer and determined its glycosylation and disulfide bond profile. Compared with soluble or solubilized S glycoproteins modified to prevent proteolytic cleavage and to retain a prefusion conformation, more of the wild-type S glycoprotein N-linked glycans are processed to complex forms. Even Asn 234, a significant percentage of which is decorated by high-mannose glycans on other characterized S trimer preparations, is predominantly modified in the Golgi compartment by processed glycans. Three incompletely occupied sites of O-linked glycosylation were detected. Viruses pseudotyped with natural variants of the serine/threonine residues implicated in O-linked glycosylation were generally infectious and exhibited sensitivity to neutralization by soluble ACE2 and convalescent antisera comparable to that of the wild-type virus. Unlike other natural cysteine variants, a Cys15Phe (C15F) mutant retained partial, but unstable, infectivity. These findings enhance our understanding of the Golgi processing of the native SARS-CoV-2 S glycoprotein carbohydrates and could assist the design of interventions. IMPORTANCE The SARS-CoV-2 coronavirus, which causes COVID-19, uses its spike glycoprotein to enter host cells. The viral spike glycoprotein is the main target of host neutralizing antibodies that help to control SARS-CoV-2 infection and are important for the protection provided by vaccines. The SARS-CoV-2 spike glycoprotein consists of a trimer of two subunits covered with a coat of carbohydrates (sugars). Here, we describe the disulfide bonds that assist the SARS-CoV-2 spike glycoprotein to assume the correct shape and the composition of the sugar moieties on the glycoprotein surface. We also evaluate the consequences of natural virus variation in O-linked sugar addition and in the cysteine residues involved in disulfide bond formation. This information can expedite the improvement of vaccines and therapies for COVID-19.
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12
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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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13
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Kacher YG, Karlova MG, Glukhov GS, Zhang H, Zaklyazminskaya EV, Loussouarn G, Sokolova OS. The Integrative Approach to Study of the Structure and Functions of Cardiac Voltage-Dependent Ion Channels. CRYSTALLOGR REP+ 2021. [DOI: 10.1134/s1063774521050072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Caparotta M, Puiatti M, Masone D. Artificial stabilization of the fusion pore by intra-organelle styrene-maleic acid copolymers. SOFT MATTER 2021; 17:8314-8321. [PMID: 34550159 DOI: 10.1039/d1sm00978h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Styrene-maleic acid copolymers have become an advantageous detergent-free alternative for membrane protein isolation. Since their discovery, experimental membrane protein extraction and purification by keeping intact their lipid environment has become significantly easier. With the aim of identifying new applications of these interesting copolymers, their molecular binding and functioning mechanisms have recently become intense objects of study. In this work, we describe the use of styrene-maleic acid copolymers as an artificial tool to stabilize the fusion pore. We show that when these copolymers circumscribe the water channel that defines the fusion pore, they keep it from shrinking and closing. We describe how only intra-organelle copolymers have stabilizing capabilities while extra-organelle ones have negligible or even contrary effects on the fusion pore life-time.
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Affiliation(s)
- Marcelo Caparotta
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (UNCuyo), 5500, Mendoza, Argentina
| | - Marcelo Puiatti
- Instituto de Investigaciones en Físico-Química de Córdoba (INFIQC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba (UNC), 5016, Córdoba, Argentina
| | - Diego Masone
- Facultad de Ingeniería, Universidad Nacional de Cuyo (UNCuyo), 5500, Mendoza, Argentina
- Instituto de Histología y Embriología de Mendoza (IHEM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCuyo), 5500, Mendoza, Argentina.
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15
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Pitch SG, Yao W, Szundi I, Fay J, Chen E, Shumate A, Kliger DS, Farrens DL. Functional integrity of membrane protein rhodopsin solubilized by styrene-maleic acid copolymer. Biophys J 2021; 120:3508-3515. [PMID: 34022241 DOI: 10.1016/j.bpj.2021.05.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 04/18/2021] [Accepted: 05/13/2021] [Indexed: 11/25/2022] Open
Abstract
Membrane proteins often require solubilization to study their structure or define the mechanisms underlying their function. In this study, the functional properties of the membrane protein rhodopsin in its native lipid environment were investigated after being solubilized with styrene-maleic acid (SMA) copolymer. The static absorption spectra of rhodopsin before and after the addition of SMA were recorded at room temperature to quantify the amount of membrane protein solubilized. The samples were then photobleached to analyze the functionality of rhodopsin upon solubilization. Samples with low or high SMA/rhodopsin ratios were compared to find a threshold in which the maximal amount of active rhodopsin was solubilized from membrane suspensions. Interestingly, whereas the highest SMA/rhodopsin ratios yielded the most solubilized rhodopsin, the rhodopsin produced under these conditions could not reach the active (Meta II) state upon photoactivation. The results confirm that SMA is a useful tool for membrane protein research, but SMA added in excess can interfere with the dynamics of protein activation.
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Affiliation(s)
- Stephanie G Pitch
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Weekie Yao
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon
| | - Istvan Szundi
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Jonathan Fay
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon
| | - Eefei Chen
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Anthony Shumate
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon
| | - David S Kliger
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - David L Farrens
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon.
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16
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Zhang S, Go EP, Ding H, Anang S, Kappes JC, Desaire H, Sodroski J. Analysis of glycosylation and disulfide bonding of wild-type SARS-CoV-2 spike glycoprotein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021. [PMID: 33821278 PMCID: PMC8020978 DOI: 10.1101/2021.04.01.438120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The SARS-CoV-2 coronavirus, the etiologic agent of COVID-19, uses its spike (S) glycoprotein anchored in the viral membrane to enter host cells. The S glycoprotein is the major target for neutralizing antibodies elicited by natural infection and by vaccines. Approximately 35% of the SARS-CoV-2 S glycoprotein consists of carbohydrate, which can influence virus infectivity and susceptibility to antibody inhibition. We found that virus-like particles produced by coexpression of SARS-CoV-2 S, M, E and N proteins contained spike glycoproteins that were extensively modified by complex carbohydrates. We used a fucose-selective lectin to enrich the Golgi-resident fraction of a wild-type SARS-CoV-2 S glycoprotein trimer, and determined its glycosylation and disulfide bond profile. Compared with soluble or solubilized S glycoproteins modified to prevent proteolytic cleavage and to retain a prefusion conformation, more of the wild-type S glycoprotein N-linked glycans are processed to complex forms. Even Asn 234, a significant percentage of which is decorated by high-mannose glycans on soluble and virion S trimers, is predominantly modified in the Golgi by processed glycans. Three incompletely occupied sites of O-linked glycosylation were detected. Viruses pseudotyped with natural variants of the serine/threonine residues implicated in O-linked glycosylation were generally infectious and exhibited sensitivity to neutralization by soluble ACE2 and convalescent antisera comparable to that of the wild-type virus. Unlike other natural cysteine variants, a Cys15Phe (C15F) mutant retained partial, but unstable, infectivity. These findings enhance our understanding of the Golgi processing of the native SARS-CoV-2 S glycoprotein carbohydrates and could assist the design of interventions.
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17
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Probing Structural Dynamics of Membrane Proteins Using Electron Paramagnetic Resonance Spectroscopic Techniques. BIOPHYSICA 2021. [DOI: 10.3390/biophysica1020009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Membrane proteins are essential for the survival of living organisms. They are involved in important biological functions including transportation of ions and molecules across the cell membrane and triggering the signaling pathways. They are targets of more than half of the modern medical drugs. Despite their biological significance, information about the structural dynamics of membrane proteins is lagging when compared to that of globular proteins. The major challenges with these systems are low expression yields and lack of appropriate solubilizing medium required for biophysical techniques. Electron paramagnetic resonance (EPR) spectroscopy coupled with site directed spin labeling (SDSL) is a rapidly growing powerful biophysical technique that can be used to obtain pertinent structural and dynamic information on membrane proteins. In this brief review, we will focus on the overview of the widely used EPR approaches and their emerging applications to answer structural and conformational dynamics related questions on important membrane protein systems.
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18
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A Three-Dimensional Model of the Yeast Transmembrane Sensor Wsc1 Obtained by SMA-Based Detergent-Free Purification and Transmission Electron Microscopy. J Fungi (Basel) 2021; 7:jof7020118. [PMID: 33562593 PMCID: PMC7915640 DOI: 10.3390/jof7020118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/31/2022] Open
Abstract
The cell wall sensor Wsc1 belongs to a small family of transmembrane proteins, which are crucial to sustain cell integrity in yeast and other fungi. Wsc1 acts as a mechanosensor of the cell wall integrity (CWI) signal transduction pathway which responds to external stresses. Here we report on the purification of Wsc1 by its trapping in water-soluble polymer-stabilized lipid nanoparticles, obtained with an amphipathic styrene-maleic acid (SMA) copolymer. The latter was employed to transfer tagged sensors from their native yeast membranes into SMA/lipid particles (SMALPs), which allows their purification in a functional state, i.e., avoiding denaturation. The SMALPs composition was characterized by fluorescence correlation spectroscopy, followed by two-dimensional image acquisition from single particle transmission electron microscopy to build a three-dimensional model of the sensor. The latter confirms that Wsc1 consists of a large extracellular domain connected to a smaller intracellular part by a single transmembrane domain, which is embedded within the hydrophobic moiety of the lipid bilayer. The successful extraction of a sensor from the yeast plasma membrane by a detergent-free procedure into a native-like membrane environment provides new prospects for in vitro structural and functional studies of yeast plasma proteins which are likely to be applicable to other fungi, including plant and human pathogens.
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19
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Birch J, Cheruvara H, Gamage N, Harrison PJ, Lithgo R, Quigley A. Changes in Membrane Protein Structural Biology. BIOLOGY 2020; 9:E401. [PMID: 33207666 PMCID: PMC7696871 DOI: 10.3390/biology9110401] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/21/2022]
Abstract
Membrane proteins are essential components of many biochemical processes and are important pharmaceutical targets. Membrane protein structural biology provides the molecular rationale for these biochemical process as well as being a highly useful tool for drug discovery. Unfortunately, membrane protein structural biology is a difficult area of study due to low protein yields and high levels of instability especially when membrane proteins are removed from their native environments. Despite this instability, membrane protein structural biology has made great leaps over the last fifteen years. Today, the landscape is almost unrecognisable. The numbers of available atomic resolution structures have increased 10-fold though advances in crystallography and more recently by cryo-electron microscopy. These advances in structural biology were achieved through the efforts of many researchers around the world as well as initiatives such as the Membrane Protein Laboratory (MPL) at Diamond Light Source. The MPL has helped, provided access to and contributed to advances in protein production, sample preparation and data collection. Together, these advances have enabled higher resolution structures, from less material, at a greater rate, from a more diverse range of membrane protein targets. Despite this success, significant challenges remain. Here, we review the progress made and highlight current and future challenges that will be overcome.
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Affiliation(s)
- James Birch
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Harish Cheruvara
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Nadisha Gamage
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Peter J. Harrison
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
| | - Ryan Lithgo
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, Leicestershire, UK
| | - Andrew Quigley
- Membrane Protein Laboratory, Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (J.B.); (H.C.); (N.G.); (P.J.H.); (R.L.)
- Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot OX11 0FA, UK
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20
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Yeh V, Goode A, Bonev BB. Membrane Protein Structure Determination and Characterisation by Solution and Solid-State NMR. BIOLOGY 2020; 9:E396. [PMID: 33198410 PMCID: PMC7697852 DOI: 10.3390/biology9110396] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/08/2020] [Accepted: 11/11/2020] [Indexed: 12/25/2022]
Abstract
Biological membranes define the interface of life and its basic unit, the cell. Membrane proteins play key roles in membrane functions, yet their structure and mechanisms remain poorly understood. Breakthroughs in crystallography and electron microscopy have invigorated structural analysis while failing to characterise key functional interactions with lipids, small molecules and membrane modulators, as well as their conformational polymorphism and dynamics. NMR is uniquely suited to resolving atomic environments within complex molecular assemblies and reporting on membrane organisation, protein structure, lipid and polysaccharide composition, conformational variations and molecular interactions. The main challenge in membrane protein studies at the atomic level remains the need for a membrane environment to support their fold. NMR studies in membrane mimetics and membranes of increasing complexity offer close to native environments for structural and molecular studies of membrane proteins. Solution NMR inherits high resolution from small molecule analysis, providing insights from detergent solubilised proteins and small molecular assemblies. Solid-state NMR achieves high resolution in membrane samples through fast sample spinning or sample alignment. Recent developments in dynamic nuclear polarisation NMR allow signal enhancement by orders of magnitude opening new opportunities for expanding the applications of NMR to studies of native membranes and whole cells.
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Affiliation(s)
| | | | - Boyan B. Bonev
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; (V.Y.); (A.G.)
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21
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Bernhard M, Laube B. Thermophoretic analysis of ligand-specific conformational states of the inhibitory glycine receptor embedded in copolymer nanodiscs. Sci Rep 2020; 10:16569. [PMID: 33024136 PMCID: PMC7538598 DOI: 10.1038/s41598-020-73157-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/10/2020] [Indexed: 11/28/2022] Open
Abstract
The glycine receptor (GlyR), a member of the pentameric ligand-gated ion channel family (pLGIC), displays remarkable variations in the affinity and efficacy of the full agonist glycine and the partial agonist taurine depending on the cell system used. Despite detailed insights in the GlyR three-dimensional structure and activation mechanism, little is known about conformational rearrangements induced by these agonists. Here, we characterized the conformational states of the α1 GlyR upon binding of glycine and taurine by microscale thermophoresis expressed in HEK293 cells and Xenopus oocytes after solubilization in amphipathic styrene-maleic acid copolymer nanodiscs. Our results show that glycine and taurine induce different conformational transitions of the GlyR upon ligand binding. In contrast, the variability of agonist affinity is not mediated by an altered conformational change. Thus, our data shed light on specific agonist induced conformational features and mechanisms of pLGIC upon ligand binding determining receptor activation in native environments.
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Affiliation(s)
- Max Bernhard
- Department of Biology, Neurophysiology and Neurosensory Systems, Technical University of Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany
| | - Bodo Laube
- Department of Biology, Neurophysiology and Neurosensory Systems, Technical University of Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany.
- Centre for Synthetic Biology, Technical University of Darmstadt, 64283, Darmstadt, Germany.
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22
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Phan MD, Korotych OI, Brady NG, Davis MM, Satija SK, Ankner JF, Bruce BD. X-ray and Neutron Reflectivity Studies of Styrene-Maleic Acid Copolymer Interactions with Galactolipid-Containing Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3970-3980. [PMID: 32207953 DOI: 10.1021/acs.langmuir.9b03817] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Styrene-maleic acid (SMA) copolymers have recently gained attention for their ability to facilitate the detergent-free solubilization of membrane protein complexes and their native boundary lipids into polymer-encapsulated, nanosized lipid particles, referred to as SMALPs. However, the interfacial interactions between SMA and lipids, which dictate the mechanism, efficiency, and selectivity of lipid and membrane protein extraction, are barely understood. Our recent finding has shown that SMA 1440, a chemical derivative of the SMA family with a functionalized butoxyethanol group, was most active in galactolipid-rich membranes, as opposed to phospholipid membranes. In the present work, we have performed X-ray reflectometry (XRR) and neutron reflectometry (NR) on the lipid monolayers at the liquid-air interface followed by the SMA copolymer adsorption. XRR and Langmuir Π-A isotherms captured the fluidifying effect of galactolipids, which allowed SMA copolymers to infiltrate easily into the lipid membranes. NR results revealed the detailed structural arrangement of SMA 1440 copolymers within the membranes and highlighted the partition of butoxyethanol group into the lipid tail region. This work allows us to propose a possible mechanism for the membrane solubilization by SMA.
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Affiliation(s)
- Minh D Phan
- Large-Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Olena I Korotych
- Department of Biochemistry, and Cellular, and Molecular Biology, University of Tennessee at Knoxville, Knoxville, Tennessee 37966, United States
| | - Nathan G Brady
- Department of Biochemistry, and Cellular, and Molecular Biology, University of Tennessee at Knoxville, Knoxville, Tennessee 37966, United States
| | - Madeline M Davis
- Department of Biochemistry, and Cellular, and Molecular Biology, University of Tennessee at Knoxville, Knoxville, Tennessee 37966, United States
| | - Sushil K Satija
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - John F Ankner
- Large-Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Barry D Bruce
- Department of Biochemistry, and Cellular, and Molecular Biology, University of Tennessee at Knoxville, Knoxville, Tennessee 37966, United States
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee 37966, United States
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23
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Sahu ID, Dixit G, Reynolds WD, Kaplevatsky R, Harding BD, Jaycox CK, McCarrick RM, Lorigan GA. Characterization of the Human KCNQ1 Voltage Sensing Domain (VSD) in Lipodisq Nanoparticles for Electron Paramagnetic Resonance (EPR) Spectroscopic Studies of Membrane Proteins. J Phys Chem B 2020; 124:2331-2342. [PMID: 32130007 DOI: 10.1021/acs.jpcb.9b11506] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Membrane proteins are responsible for conducting essential biological functions that are necessary for the survival of living organisms. In spite of their physiological importance, limited structural information is currently available as a result of challenges in applying biophysical techniques for studying these protein systems. Electron paramagnetic resonance (EPR) spectroscopy is a very powerful technique to study the structural and dynamic properties of membrane proteins. However, the application of EPR spectroscopy to membrane proteins in a native membrane-bound state is extremely challenging due to the complexity observed in inhomogeneity sample preparation and the dynamic motion of the spin label. Detergent micelles are very popular membrane mimetics for membrane proteins due to their smaller size and homogeneity, providing high-resolution structure analysis by solution NMR spectroscopy. However, it is important to test whether the protein structure in a micelle environment is the same as that of its membrane-bound state. Lipodisq nanoparticles or styrene-maleic acid copolymer-lipid nanoparticles (SMALPs) have been introduced as a potentially good membrane-mimetic system for structural studies of membrane proteins. Recently, we reported on the EPR characterization of the KCNE1 membrane protein having a single transmembrane incorporated into lipodisq nanoparticles. In this work, lipodisq nanoparticles were used as a membrane mimic system for probing the structural and dynamic properties of the more complicated membrane protein system human KCNQ1 voltage sensing domain (Q1-VSD) having four transmembrane helices using site-directed spin-labeling EPR spectroscopy. Characterization of spin-labeled Q1-VSD incorporated into lipodisq nanoparticles was carried out using CW-EPR spectral line shape analysis and pulsed EPR double-electron electron resonance (DEER) measurements. The CW-EPR spectra indicate an increase in spectral line broadening with the addition of the styrene-maleic acid (SMA) polymer which approaches close to the rigid limit providing a homogeneous stabilization of the protein-lipid complex. Similarly, EPR DEER measurements indicated a superior quality of distance measurement with an increase in the phase memory time (Tm) values upon incorporation of the sample into lipodisq nanoparticles when compared to proteoliposomes. These results are consistent with the solution NMR structural studies on the Q1-VSD. This study will be beneficial for researchers working on investigating the structural and dynamic properties of more complicated membrane protein systems using lipodisq nanoparticles.
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Affiliation(s)
- Indra D Sahu
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States.,Natural Science Division, Campbellsville University, Campbellsville, Kentucky 42718, United States
| | - Gunjan Dixit
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Warren D Reynolds
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Ryan Kaplevatsky
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Benjamin D Harding
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Colleen K Jaycox
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Robert M McCarrick
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
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24
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Factors influencing the solubilization of membrane proteins from Escherichia coli membranes by styrene–maleic acid copolymers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183125. [DOI: 10.1016/j.bbamem.2019.183125] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/17/2019] [Accepted: 11/10/2019] [Indexed: 12/21/2022]
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25
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Colbasevici A, Voskoboynikova N, Orekhov PS, Bozdaganyan ME, Karlova MG, Sokolova OS, Klare JP, Mulkidjanian AY, Shaitan KV, Steinhoff HJ. Lipid dynamics in nanoparticles formed by maleic acid-containing copolymers: EPR spectroscopy and molecular dynamics simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183207. [PMID: 31987867 DOI: 10.1016/j.bbamem.2020.183207] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 12/11/2022]
Abstract
Amphiphilic maleic acid-containing copolymers account for a recent methodical breakthrough in the study of membrane proteins. Their application enables a detergent-free extraction of membrane proteins from lipid bilayers, yielding stable water-soluble, discoidal lipid bilayer particles with incorporated proteins, which are wrapped with copolymers. Although many studies confirm the potential of this approach for membrane protein research, the interactions between the maleic acid-containing copolymers and extracted lipids, as well as possible effects of the copolymers on lipid-embedded proteins deserve further scrutinization. Here, we combine electron paramagnetic resonance spectroscopy and coarse-grain molecular dynamics simulations to compare the distribution and dynamics of lipids in lipid particles of phospholipid bilayers encased either by an aliphatic diisobutylene/maleic acid copolymer (DIBMALPs) or by an aromatic styrene/maleic acid copolymer (SMALPs). Nitroxides located at the 5th, 12th or 16th carbon atom positions in phosphatidylcholine-based spin labels experience restrictions of their reorientational motion depending on the type of encasing copolymer. The dynamics of the lipids was less constrained in DIBMALPs than in SMALPs with the affinity of spin labeled lipids to the polymeric rim being more pronounced in SMALPs.
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Affiliation(s)
| | | | - Philipp S Orekhov
- Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia; Sechenov University, Moscow 119146, Russia; Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Marine E Bozdaganyan
- Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia; Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow 119991, Russia
| | - Maria G Karlova
- Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Olga S Sokolova
- Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Johann P Klare
- Department of Physics, Osnabrueck University, 49069 Osnabrueck, Germany
| | - Armen Y Mulkidjanian
- Department of Physics, Osnabrueck University, 49069 Osnabrueck, Germany; A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia; Department of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Konstantin V Shaitan
- Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow 119991, Russia
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26
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Bada Juarez JF, Muñoz-García JC, Inácio Dos Reis R, Henry A, McMillan D, Kriek M, Wood M, Vandenplas C, Sands Z, Castro L, Taylor R, Watts A. Detergent-free extraction of a functional low-expressing GPCR from a human cell line. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183152. [PMID: 31843475 DOI: 10.1016/j.bbamem.2019.183152] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/21/2019] [Accepted: 12/05/2019] [Indexed: 01/02/2023]
Abstract
Dopamine receptors (DRs) are class A G-Protein Coupled Receptors (GPCRs) prevalent in the central nervous system (CNS). These receptors mediate physiological functions ranging from voluntary movement and reward recognition to hormonal regulation and hypertension. Drugs targeting dopaminergic neurotransmission have been employed to treat several neurological and psychiatric disorders, including Parkinson's disease, schizophrenia, Huntington's disease, attention deficit hyperactivity disorder (ADHD), and Tourette's syndrome. In vivo, incorporation of GPCRs into lipid membranes is known to be key to their biological function and, by inference, maintenance of their tertiary structure. A further significant challenge in the structural and biochemical characterization of human DRs is their low levels of expression in mammalian cells. Thus, the purification and enrichment of DRs whilst retaining their structural integrity and function is highly desirable for biophysical studies. A promising new approach is the use of styrene-maleic acid (SMA) copolymer to solubilize GPCRs directly in their native environment, to produce polymer-assembled Lipodisqs (LQs). We have developed a novel methodology to yield detergent-free D1-containing Lipodisqs directly from HEK293f cells expressing wild-type human dopamine receptor 1 (D1). We demonstrate that D1 in the Lipodisq retains activity comparable to that in the native environment and report, for the first time, the affinity constant for the interaction of the peptide neurotransmitter neurotensin (NT) with D1, in the native state.
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Affiliation(s)
| | - Juan C Muñoz-García
- Biochemistry Department, Oxford University, South Parks Road, Oxford OX1 3QU, UK; School of Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK
| | | | | | | | - Marco Kriek
- UCB Celltech, 216 Bath Road, Slough SL1 3WE, UK
| | - Martyn Wood
- UCB BioPharma SPRL, Braine-l'Alleud, Belgium
| | | | - Zara Sands
- UCB Celltech, 216 Bath Road, Slough SL1 3WE, UK
| | - Luis Castro
- UCB Celltech, 216 Bath Road, Slough SL1 3WE, UK
| | | | - Anthony Watts
- Biochemistry Department, Oxford University, South Parks Road, Oxford OX1 3QU, UK.
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27
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Lee SC, Collins R, Lin YP, Jamshad M, Broughton C, Harris SA, Hanson BS, Tognoloni C, Parslow RA, Terry AE, Rodger A, Smith CJ, Edler KJ, Ford R, Roper DI, Dafforn TR. Nano-encapsulated Escherichia coli Divisome Anchor ZipA, and in Complex with FtsZ. Sci Rep 2019; 9:18712. [PMID: 31822696 PMCID: PMC6904479 DOI: 10.1038/s41598-019-54999-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 11/10/2019] [Indexed: 12/21/2022] Open
Abstract
The E. coli membrane protein ZipA, binds to the tubulin homologue FtsZ, in the early stage of cell division. We isolated ZipA in a Styrene Maleic Acid lipid particle (SMALP) preserving its position and integrity with native E. coli membrane lipids. Direct binding of ZipA to FtsZ is demonstrated, including FtsZ fibre bundles decorated with ZipA. Using Cryo-Electron Microscopy, small-angle X-ray and neutron scattering, we determine the encapsulated-ZipA structure in isolation, and in complex with FtsZ to a resolution of 1.6 nm. Three regions can be identified from the structure which correspond to, SMALP encapsulated membrane and ZipA transmembrane helix, a separate short compact tether, and ZipA globular head which binds FtsZ. The complex extends 12 nm from the membrane in a compact structure, supported by mesoscale modelling techniques, measuring the movement and stiffness of the regions within ZipA provides molecular scale analysis and visualisation of the early divisome.
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Affiliation(s)
- Sarah C Lee
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Richard Collins
- Faculty of Life Sciences, A4032 Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - Yu-Pin Lin
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Mohammed Jamshad
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Claire Broughton
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - Sarah A Harris
- School of Physics and Astronomy and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
| | - Benjamin S Hanson
- School of Physics and Astronomy and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
| | - Cecilia Tognoloni
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Rosemary A Parslow
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Ann E Terry
- MAX IV Laboratory Lund University, P.O. Box 118, SE-221 00, Lund, Sweden
| | - Alison Rodger
- Department of Molecular Sciences, Macquarie University, Macquarie, NSW, 2109, Australia
| | - Corinne J Smith
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - Karen J Edler
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Robert Ford
- Faculty of Life Sciences, A4032 Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - David I Roper
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - Timothy R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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28
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Desrames A, Genetet S, Delcourt MP, Goossens D, Mouro-Chanteloup I. Detergent-free isolation of native red blood cell membrane complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183126. [PMID: 31738902 DOI: 10.1016/j.bbamem.2019.183126] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/29/2019] [Accepted: 11/10/2019] [Indexed: 12/15/2022]
Abstract
Over the past few decades, studies on the red blood cell (RBC) membrane gave rise to increasingly sophisticated although divergent models of its structural organization, since investigations were often performed in denaturing conditions using detergents. To access soluble isolated RBC membrane complexes with the preservation of their interactions and conformations, we decided to apply the recent SMALP (Styrene Maleic Acid Lipid Particles) technology to RBC ghosts. Depending on the ionic strength of buffers in which ghost membranes were resuspended, the isolated proteins within SMALPs could differ on Coomassie-stained gels, but with few changes when compared to ghost membrane SDS lysates. We subsequently produced SMALPs derived from ghosts from two different blood group phenotypes, RhD-positive and RhD-negative, both types of RBC expressing the RhCE proteins but only RhD-positive cells being able to express the RhD proteins. This allowed the isolation, by size exclusion chromatography (SEC), of soluble fractions containing the Rh complex, including the RhD protein or not, within SMALPs. The use a conformation-dependent anti-RhD antibody in immunoprecipitation studies performed on SEC fractions of SMALPs containing Rh proteins clearly demonstrated that the RhD protein, which was only present in SMALPs prepared from RhD-positive RBC ghosts, has preserved at least one important conformational RhD epitope. This approach opens new perspectives in the field of the erythroid membrane study, such as visualization of RBC membrane complexes in native conditions by cryo-electron microscopy (CryoEM) or immuno-tests with conformation-dependent antibodies against blood group antigens on separated and characterized SMALPs containing RBC membrane proteins.
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Affiliation(s)
- Alexandra Desrames
- Université de Paris, UMR_S1134, BIGR, Inserm, F-75015 Paris, France; Institut National de la transfusion sanguine, F-75015 Paris, France
| | - Sandrine Genetet
- Université de Paris, UMR_S1134, BIGR, Inserm, F-75015 Paris, France; Institut National de la transfusion sanguine, F-75015 Paris, France
| | - Maëlenn Païline Delcourt
- Université de Paris, UMR_S1134, BIGR, Inserm, F-75015 Paris, France; Institut National de la transfusion sanguine, F-75015 Paris, France
| | | | - Isabelle Mouro-Chanteloup
- Université de Paris, UMR_S1134, BIGR, Inserm, F-75015 Paris, France; Institut National de la transfusion sanguine, F-75015 Paris, France.
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29
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Klöpfer K, Hagn F. Beyond detergent micelles: The advantages and applications of non-micellar and lipid-based membrane mimetics for solution-state NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:271-283. [PMID: 31779883 DOI: 10.1016/j.pnmrs.2019.08.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/20/2019] [Accepted: 08/22/2019] [Indexed: 06/10/2023]
Abstract
Membrane proteins are important players in signal transduction and the exchange of metabolites within or between cells. Thus, this protein class is the target of around 60 % of currently marketed drugs, emphasizing their essential biological role. Besides functional assays, structural and dynamical investigations on this protein class are crucial to fully understanding their functionality. Even though X-ray crystallography and electron microscopy are the main methods to determine structures of membrane proteins and their complexes, NMR spectroscopy can contribute essential information on systems that (a) do not crystallize and (b) are too small for EM. Furthermore, NMR is a versatile tool for monitoring functional dynamics of biomolecules at various time scales. A crucial aspect of such studies is the use of a membrane mimetic that resembles a native environment and thus enables the extraction of functional insights. In recent decades, the membrane protein NMR community has moved from rather harsh detergents to membrane systems having more native-like properties. In particular, most recently phospholipid nanodiscs have been developed and optimized mainly for solution-state NMR but are now also being used for solid-state NMR spectroscopy. Nanodiscs consist of a patch of a planar lipid bilayer that is encircled by different (bio-)polymers to form particles of defined and tunable size. In this review, we provide an overview of available membrane mimetics, including nanodiscs, amphipols and bicelles, that are suitable for high-resolution NMR spectroscopy and describe how these advanced membrane mimetics can facilitate NMR studies on the structure and dynamics of membrane proteins. Since the stability of membrane proteins depends critically on the chosen membrane mimetic, we emphasize the importance of a suitable system that is not necessarily developed for solution-state NMR applications and hence requires optimization for each membrane protein. However, lipid-based membrane mimetics offer the possibility of performing NMR experiments at elevated temperatures and studying ligand and partner protein complexes as well as their functional dynamics in a realistic membrane environment. In order to be able to make an informed decision during the selection of a suitable membrane system, we provide a detailed overview of the available options for various membrane protein classes and thereby facilitate this often-difficult selection process for a broad range of desired NMR applications.
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Affiliation(s)
- Kai Klöpfer
- Bavarian NMR Center at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85747 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Franz Hagn
- Bavarian NMR Center at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85747 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
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30
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Entova S, Guan Z, Imperiali B. Investigation of the conserved reentrant membrane helix in the monotopic phosphoglycosyl transferase superfamily supports key molecular interactions with polyprenol phosphate substrates. Arch Biochem Biophys 2019; 675:108111. [PMID: 31563509 DOI: 10.1016/j.abb.2019.108111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 01/10/2023]
Abstract
Long-chain polyprenol phosphates feature in membrane-associated glycoconjugate biosynthesis pathways across domains of life. These unique amphiphilic molecules are best known as substrates of polytopic membrane proteins, including polyprenol-phosphate phosphoglycosyl and glycosyl transferases, and as components of more complex substrates. The linear polyprenols are constrained by double bond geometry and lend themselves well to interactions with polytopic membrane proteins, in which multiple transmembrane helices form a rich landscape for interactions. Recently, a new superfamily of monotopic phosphoglycosyl transferase enzymes has been identified that interacts with polyprenol phosphate substrates via a single reentrant membrane helix. Intriguingly, despite the dramatic differences in their membrane-interaction domains, both polytopic and monotopic enzymes similarly favor a unique cis/trans geometry in their polyprenol phosphate substrates. Herein, we present a multipronged biochemical and biophysical study of PglC, a monotopic phosphoglycosyl transferase that catalyzes the first membrane-committed step in N-linked glycoprotein biosynthesis in Campylobacter jejuni. We probe the significance of polyprenol phosphate geometry both in mediating substrate binding to PglC and in modulating the local membrane environment. Geometry is found to be important for binding to PglC; a conserved proline residue in the reentrant membrane helix is determined to drive polyprenol phosphate recognition and specificity. Pyrene fluorescence studies show that polyprenol phosphates at physiologically-relevant levels increase the disorder of the local lipid bilayer; however, this effect is confined to polyprenol phosphates with specific isoprene geometries. The molecular insights from this study may shed new light on the interactions of polyprenol phosphates with diverse membrane-associated proteins in glycoconjugate biosynthesis.
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Affiliation(s)
- Sonya Entova
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA, 02139, USA.
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, 10 Duke Medicine Circle, Durham, NC, 27710, USA.
| | - Barbara Imperiali
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA, 02139, USA; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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31
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Puthenveetil R, Vinogradova O. Solution NMR: A powerful tool for structural and functional studies of membrane proteins in reconstituted environments. J Biol Chem 2019; 294:15914-15931. [PMID: 31551353 DOI: 10.1074/jbc.rev119.009178] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A third of the genes in prokaryotic and eukaryotic genomes encode membrane proteins that are either essential for signal transduction and solute transport or function as scaffold structures. Unlike many of their soluble counterparts, the overall structural and functional organization of membrane proteins is sparingly understood. Recent advances in X-ray crystallography, cryo-EM, and nuclear magnetic resonance (NMR) are closing this gap by enabling an in-depth view of these ever-elusive proteins at atomic resolution. Despite substantial technological advancements, however, the overall proportion of membrane protein entries in the Protein Data Bank (PDB) remains <4%. This paucity is mainly attributed to difficulties associated with their expression and purification, propensity to form large multisubunit complexes, and challenges pertinent to identification of an ideal detergent, lipid, or detergent/lipid mixture that closely mimic their native environment. NMR is a powerful technique to obtain atomic-resolution and dynamic details of a protein in solution. This is accomplished through an assortment of isotopic labeling schemes designed to acquire multiple spectra that facilitate deduction of the final protein structure. In this review, we discuss current approaches and technological developments in the determination of membrane protein structures by solution NMR and highlight recent structural and mechanistic insights gained with this technique. We also discuss strategies for overcoming size limitations in NMR applications, and we explore a plethora of membrane mimetics available for the structural and mechanistic understanding of these essential cellular proteins.
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Affiliation(s)
- Robbins Puthenveetil
- Department of Molecular and Cell Biology, college of liberal arts and sciences, University of Connecticut at Storrs, Storrs, Connecticut 06269
| | - Olga Vinogradova
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut at Storrs, Storrs, Connecticut 06269
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32
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SMA-PAGE: A new method to examine complexes of membrane proteins using SMALP nano-encapsulation and native gel electrophoresis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1437-1445. [DOI: 10.1016/j.bbamem.2019.05.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 05/02/2019] [Accepted: 05/19/2019] [Indexed: 12/22/2022]
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33
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Lipodisqs for eukaryote lipidomics with retention of viability: Sensitivity and resistance to Leucobacter infection linked to C.elegans cuticle composition. Chem Phys Lipids 2019; 222:51-58. [DOI: 10.1016/j.chemphyslip.2019.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 11/18/2022]
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34
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Single-particle cryo-EM studies of transmembrane proteins in SMA copolymer nanodiscs. Chem Phys Lipids 2019; 221:114-119. [PMID: 30940443 DOI: 10.1016/j.chemphyslip.2019.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 03/14/2019] [Accepted: 03/14/2019] [Indexed: 11/21/2022]
Abstract
Styrene-maleic acid (SMA) copolymers can extract membrane proteins from native membranes along with lipids as nanodiscs. Preparation with SMA is fast, cost-effective, and captures the native protein-lipid interactions. On the other hand, cryo-EM has become increasingly successful and efficient for structural determinations of membrane proteins, with biochemical sample preparation often the bottleneck. Three recent cryo-EM studies on the efflux transporter AcrB and the alternative complex III: cyt c oxidase supercomplex have demonstrated the potential of SMA nanodisc samples to yield high-resolution structure information of membrane proteins.
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35
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Bada Juarez JF, Harper AJ, Judge PJ, Tonge SR, Watts A. From polymer chemistry to structural biology: The development of SMA and related amphipathic polymers for membrane protein extraction and solubilisation. Chem Phys Lipids 2019; 221:167-175. [PMID: 30940445 DOI: 10.1016/j.chemphyslip.2019.03.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/15/2019] [Accepted: 03/15/2019] [Indexed: 12/13/2022]
Abstract
Nanoparticles assembled with poly(styrene-maleic acid) copolymers, identified in the literature as Lipodisq, SMALPs or Native Nanodisc, are routinely used as membrane mimetics to stabilise protein structures in their native conformation. To date, transmembrane proteins of varying complexity (up to 8 beta strands or 48 alpha helices) and of a range of molecular weights (from 27 kDa up to 500 kDa) have been incorporated into this particle system for structural and functional studies. SMA and related amphipathic polymers have become versatile components of the biochemist's tool kit for the stabilisation, extraction and structural characterization of membrane proteins by techniques including cryo-EM and X-ray crystallography. Lipodisq formation does not require the use of conventional detergents and thus avoids their associated detrimental consequences. Here the development of this technology, from its fundamental concept and design to the diverse range of experimental methodologies to which it can now be applied, will be reviewed.
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Affiliation(s)
| | - Andrew J Harper
- Malvern Cosmeceutics Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, WR14 3SZ, UK
| | - Peter J Judge
- Biochemistry Department, Oxford University, South Parks Road, Oxford, OX1 3QU, UK
| | - Stephen R Tonge
- Malvern Cosmeceutics Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, WR14 3SZ, UK
| | - Anthony Watts
- Biochemistry Department, Oxford University, South Parks Road, Oxford, OX1 3QU, UK.
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36
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Calzada E, Avery E, Sam PN, Modak A, Wang C, McCaffery JM, Han X, Alder NN, Claypool SM. Phosphatidylethanolamine made in the inner mitochondrial membrane is essential for yeast cytochrome bc 1 complex function. Nat Commun 2019; 10:1432. [PMID: 30926815 PMCID: PMC6441012 DOI: 10.1038/s41467-019-09425-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 03/11/2019] [Indexed: 12/18/2022] Open
Abstract
Of the four separate PE biosynthetic pathways in eukaryotes, one occurs in the mitochondrial inner membrane (IM) and is executed by phosphatidylserine decarboxylase (Psd1). Deletion of Psd1 is lethal in mice and compromises mitochondrial function. We hypothesize that this reflects inefficient import of non-mitochondrial PE into the IM. Here, we test this by re-wiring PE metabolism in yeast by re-directing Psd1 to the outer mitochondrial membrane or the endomembrane system and show that PE can cross the IMS in both directions. Nonetheless, PE synthesis in the IM is critical for cytochrome bc1 complex (III) function and mutations predicted to disrupt a conserved PE-binding site in the complex III subunit, Qcr7, impair complex III activity similar to PSD1 deletion. Collectively, these data challenge the current dogma of PE trafficking and demonstrate that PE made in the IM by Psd1 support the intrinsic functionality of complex III. Phosphatidylethanolamine (PE) is synthesized by four separate pathways, although surprisingly, perturbing mitochondrial PE synthesis compromises mitochondrial function. Here, the authors show that mitochondrial PE synthesis is required for Complex III function and challenge PE trafficking dogma.
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Affiliation(s)
- Elizabeth Calzada
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Erica Avery
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Pingdewinde N Sam
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Arnab Modak
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Chunyan Wang
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - J Michael McCaffery
- Integrated Imaging Center, Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Xianlin Han
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Nathan N Alder
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Steven M Claypool
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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37
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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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Native Nanodiscs and the Convergence of Lipidomics, Metabolomics, Interactomics and Proteomics. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9061230] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The omics disciplines remain largely distinct sciences due to the necessity of separating molecular classes for different assays. For example, water-soluble and lipid bilayer-bound proteins and metabolites are usually studied separately. Nonetheless, it is at the interface between these sciences where biology happens. That is, lipid-interacting proteins typically recognize and transduce signals and regulate the flow of metabolites in the cell. Technologies are emerging to converge the omics. It is now possible to separate intact membrane:protein assemblies (memteins) directly from intact cells or cell membranes. Such complexes mediate complete metabolon, receptor, channel, and transporter functions. The use of poly(styrene-co-maleic acid) (SMA) copolymers has allowed their separation in a single step without any exposure to synthetic detergents or artificial lipids. This is a critical development as these agents typically strip away biological lipids, signals, and metabolites from their physiologically-relevant positions on proteins. The resulting SMA lipid particles (SMALPs) represent native nanodiscs that are suitable for elucidation of structures and interactions that occur in vivo. Compatible tools for resolving the contained memteins include X-ray diffraction (XRD), cryo-electron microscopy (cryoEM), mass spectrometry (MS), and nuclear magnetic resonance (NMR) spectroscopy. Recent progress shows that memteins are more representative than naked membrane proteins devoid of natural lipid and is driving the development of next generation polymers.
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Bolla JR, Agasid MT, Mehmood S, Robinson CV. Membrane Protein-Lipid Interactions Probed Using Mass Spectrometry. Annu Rev Biochem 2019; 88:85-111. [PMID: 30901263 DOI: 10.1146/annurev-biochem-013118-111508] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Membrane proteins that exist in lipid bilayers are not isolated molecular entities. The lipid molecules that surround them play crucial roles in maintaining their full structural and functional integrity. Research directed at investigating these critical lipid-protein interactions is developing rapidly. Advancements in both instrumentation and software, as well as in key biophysical and biochemical techniques, are accelerating the field. In this review, we provide a brief outline of structural techniques used to probe protein-lipid interactions and focus on the molecular aspects of these interactions obtained from native mass spectrometry (native MS). We highlight examples in which lipids have been shown to modulate membrane protein structure and show how native MS has emerged as a complementary technique to X-ray crystallography and cryo-electron microscopy. We conclude with a short perspective on future developments that aim to better understand protein-lipid interactions in the native environment.
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Affiliation(s)
- Jani Reddy Bolla
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Mark T Agasid
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Shahid Mehmood
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
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40
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Orekhov PS, Bozdaganyan ME, Voskoboynikova N, Mulkidjanian AY, Steinhoff HJ, Shaitan KV. Styrene/Maleic Acid Copolymers Form SMALPs by Pulling Lipid Patches out of the Lipid Bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:3748-3758. [PMID: 30773011 DOI: 10.1021/acs.langmuir.8b03978] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Amphiphilic copolymers composed of styrene and maleic acid (SMA) monomers caused a major methodical breakthrough in the study of membrane proteins. They were found to directly release phospholipids and membrane proteins both from artificial and natural lipid bilayers, yielding stable water-soluble discoidal SMA/lipid particles (SMALPs) of uniform size. Although many empirical studies indicate the great potency of SMALPs for membrane protein research, the mechanisms of their formation remain obscure. It is unknown which factors account for the very assembly of SMALPs and govern their uniform size. We have developed a coarse-grained (CG) molecular model of SMA copolymers based on the MARTINI CG force field and used it to probe the behavior of SMA copolymers with varying composition/charge/concentration in solution as well as their interaction with lipid membranes. First, we found that SMA copolymers tend to aggregate in solution into clusters, which could account for the uniform size of SMALPs. Next, molecular dynamics (MD) simulations showed that periodic SMA copolymers with styrene/maleic acid ratios of 2:1 ([SSM] n) and 3:1 ([SSSM] n) differently interacted with lipid bilayers. While clusters of 2:1 SMA copolymers induced membrane poration, the clusters of 3:1 SMA copolymers extracted lipid patches from the membrane yielding SMALP-like structures. Extraction of lipid patches was also observed when we simulated the behavior of 3:1 copolymers with varying lengths and statistical distribution of styrene and MA units. Analysis of MD simulation trajectories and comparison with experimental data indicate that the formation of SMALPs requires copolymer molecules with a sufficient number of units made of more than two sequential styrene monomers.
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Affiliation(s)
- Philipp S Orekhov
- Department of Biology , Lomonosov Moscow State University , Moscow 119991 , Russia
- Sechenov University , Moscow 119146 , Russia
- Moscow Institute of Physics and Technology , Dolgoprudny 141701 , Russia
| | - Marine E Bozdaganyan
- Department of Biology , Lomonosov Moscow State University , Moscow 119991 , Russia
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies , Federal Medical and Biological Agency of Russia , Moscow 123182 , Russia
| | | | | | | | - Konstantin V Shaitan
- Department of Biology , Lomonosov Moscow State University , Moscow 119991 , Russia
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41
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Detergent-free solubilization of human Kv channels expressed in mammalian cells. Chem Phys Lipids 2019; 219:50-57. [DOI: 10.1016/j.chemphyslip.2019.01.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 12/13/2022]
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42
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Teo ACK, Lee SC, Pollock NL, Stroud Z, Hall S, Thakker A, Pitt AR, Dafforn TR, Spickett CM, Roper DI. Analysis of SMALP co-extracted phospholipids shows distinct membrane environments for three classes of bacterial membrane protein. Sci Rep 2019; 9:1813. [PMID: 30755655 PMCID: PMC6372662 DOI: 10.1038/s41598-018-37962-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 12/05/2018] [Indexed: 11/24/2022] Open
Abstract
Biological characterisation of membrane proteins lags behind that of soluble proteins. This reflects issues with the traditional use of detergents for extraction, as the surrounding lipids are generally lost, with adverse structural and functional consequences. In contrast, styrene maleic acid (SMA) copolymers offer a detergent-free method for biological membrane solubilisation to produce SMA-lipid particles (SMALPs) containing membrane proteins together with their surrounding lipid environment. We report the development of a reverse-phase LC-MS/MS method for bacterial phospholipids and the first comparison of the profiles of SMALP co-extracted phospholipids from three exemplar bacterial membrane proteins with different topographies: FtsA (associated membrane protein), ZipA (single transmembrane helix), and PgpB (integral membrane protein). The data showed that while SMA treatment per se did not preferentially extract specific phospholipids from the membrane, SMALP-extracted ZipA showed an enrichment in phosphatidylethanolamines and depletion in cardiolipins compared to the bulk membrane lipid. Comparison of the phospholipid profiles of the 3 SMALP-extracted proteins revealed distinct lipid compositions for each protein: ZipA and PgpB were similar, but in FtsA samples longer chain phosphatidylglycerols and phosphatidylethanolamines were more abundant. This method offers novel information on the phospholipid interactions of these membrane proteins.
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Affiliation(s)
- Alvin C K Teo
- School of Life Sciences, Gibbet Hill Road, University of Warwick, Coventry, CV4 7AL, UK
| | - Sarah C Lee
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Naomi L Pollock
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Zoe Stroud
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Stephen Hall
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Alpesh Thakker
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Andrew R Pitt
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Timothy R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Corinne M Spickett
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - David I Roper
- School of Life Sciences, Gibbet Hill Road, University of Warwick, Coventry, CV4 7AL, UK.
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43
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44
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Overduin M, Esmaili M. Memtein: The fundamental unit of membrane-protein structure and function. Chem Phys Lipids 2019; 218:73-84. [DOI: 10.1016/j.chemphyslip.2018.11.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 11/24/2018] [Accepted: 11/28/2018] [Indexed: 12/14/2022]
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45
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Flayhan A, Mertens HDT, Ural-Blimke Y, Martinez Molledo M, Svergun DI, Löw C. Saposin Lipid Nanoparticles: A Highly Versatile and Modular Tool for Membrane Protein Research. Structure 2018; 26:345-355.e5. [PMID: 29413323 PMCID: PMC5807053 DOI: 10.1016/j.str.2018.01.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/27/2017] [Accepted: 01/10/2018] [Indexed: 11/30/2022]
Abstract
Saposin-derived lipid nanoparticles (SapNPs) are a new alternative tool for membrane protein reconstitution. Here we demonstrate the potential and advantages of SapNPs. We show that SapA has the lowest lipid specificity for SapNP formation. These nanoparticles are modular and offer a tunable range of size and composition depending on the stoichiometric ratio of lipid and saposin components. They are stable and exhibit features typical of lipid-bilayer systems. Our data suggest that SapNPs are versatile and can adapt to membrane proteins of various sizes and architectures. Using SapA and various types of lipids we could reconstitute membrane proteins of different transmembrane cross-sectional areas (from 14 to 56 transmembrane α helices). SapNP-reconstituted proteins bound their respective ligands and were more heat stable compared with the detergent-solubilized form. Moreover, SapNPs encircle membrane proteins in a compact way, allowing structural investigations of small membrane proteins in a detergent-free environment using small-angle X-ray scattering. SapA shows the lowest lipid specificity for SapNP formation SapNPs are versatile and can adapt to MPs of various sizes and architectures SapNP-reconstituted MPs are more stable than in detergent SapNPs encapsulate MPs in a compact manner
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Affiliation(s)
- Ali Flayhan
- Centre for Structural Systems Biology (CSSB), DESY, Notkestrasse 85, 22607 Hamburg, Germany; European Molecular Biology Laboratory Hamburg, Notkestrasse 85, 22607 Hamburg, Germany
| | - Haydyn D T Mertens
- European Molecular Biology Laboratory Hamburg, Notkestrasse 85, 22607 Hamburg, Germany
| | - Yonca Ural-Blimke
- Centre for Structural Systems Biology (CSSB), DESY, Notkestrasse 85, 22607 Hamburg, Germany; European Molecular Biology Laboratory Hamburg, Notkestrasse 85, 22607 Hamburg, Germany
| | - Maria Martinez Molledo
- Centre for Structural Systems Biology (CSSB), DESY, Notkestrasse 85, 22607 Hamburg, Germany; European Molecular Biology Laboratory Hamburg, Notkestrasse 85, 22607 Hamburg, Germany
| | - Dmitri I Svergun
- European Molecular Biology Laboratory Hamburg, Notkestrasse 85, 22607 Hamburg, Germany
| | - Christian Löw
- Centre for Structural Systems Biology (CSSB), DESY, Notkestrasse 85, 22607 Hamburg, Germany; European Molecular Biology Laboratory Hamburg, Notkestrasse 85, 22607 Hamburg, Germany; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles väg 2, 17177 Stockholm, Sweden.
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46
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Liu Y, Moura ECCM, Dörr JM, Scheidelaar S, Heger M, Egmond MR, Killian JA, Mohammadi T, Breukink E. Bacillus subtilis MraY in detergent-free system of nanodiscs wrapped by styrene-maleic acid copolymers. PLoS One 2018; 13:e0206692. [PMID: 30395652 PMCID: PMC6218056 DOI: 10.1371/journal.pone.0206692] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/17/2018] [Indexed: 12/25/2022] Open
Abstract
As an integral membrane protein, purification and characterization of phospho-N- acetylmuramyl- pentapeptide translocase MraY have proven difficult. Low yield and concerns of retaining stability and activity after detergent solubilization have hampered the structure-function analysis. The recently developed detergent-free styrene-maleic acid (SMA) co-polymer system offers an alternative approach that may overcome these disadvantages. In this study, we used the detergent free system to purify MraY from Bacillus subtilis. This allowed efficient extraction of MraY that was heterologously produced in Escherichia coli membranes into SMA-wrapped nanodiscs. The purified MraY embedded in these nanodiscs (SMA-MraY) was comparable to the micellar MraY extracted with a conventional detergent (DDM) with regard to the yield and the purity of the recombinant protein but required significantly less time. The predominantly alpha-helical secondary structure of the protein in SMA-wrapped nanodiscs was also more stable against heat denaturation compared to the micellar protein. Thus, this detergent-free system is amenable to extract MraY efficiently and effectively while maintaining the biophysical properties of the protein. However, the apparent activity of the SMA-MraY was reduced compared to that of the detergent-solubilized protein. The present data indicates that this is caused by a lower accessibility of the enzyme in SMA-wrapped nanodiscs towards its polyisoprenoid substrate.
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Affiliation(s)
- Yao Liu
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
| | - Elisabete C. C. M. Moura
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
| | - Jonas M. Dörr
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
| | - Stefan Scheidelaar
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
| | - Michal Heger
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
- Department of Experimental Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Maarten R. Egmond
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
| | - J. Antoinette Killian
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
| | - Tamimount Mohammadi
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
| | - Eefjan Breukink
- Department of Membrane Biochemistry and Biophysics, Institute of Biomembranes, Utrecht University, Utrecht, the Netherlands
- * E-mail:
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47
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Smirnova IA, Ädelroth P, Brzezinski P. Extraction and liposome reconstitution of membrane proteins with their native lipids without the use of detergents. Sci Rep 2018; 8:14950. [PMID: 30297885 PMCID: PMC6175888 DOI: 10.1038/s41598-018-33208-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/25/2018] [Indexed: 11/17/2022] Open
Abstract
Functional studies of membrane-bound channels, transporters or signal transducers require that the protein of interest resides in a membrane that separates two compartments. One approach that is commonly used to prepare these systems is to reconstitute the protein in liposomes. An intermediate step of this method is purification of the protein, which typically involves solubilization of the native membrane using detergent. The use of detergents often results in removal of lipids surrounding the protein, which may alter its structure and function. Here, we have employed a method for isolation of membrane proteins with a disc of their native lipids to develop an approach that allows transfer of the purified membrane protein to liposomes without the use of any detergents.
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Affiliation(s)
- Irina A Smirnova
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Pia Ädelroth
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91, Stockholm, Sweden.
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48
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Methods of reconstitution to investigate membrane protein function. Methods 2018; 147:126-141. [DOI: 10.1016/j.ymeth.2018.02.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 02/13/2018] [Indexed: 02/06/2023] Open
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49
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Xue M, Cheng L, Faustino I, Guo W, Marrink SJ. Molecular Mechanism of Lipid Nanodisk Formation by Styrene-Maleic Acid Copolymers. Biophys J 2018; 115:494-502. [PMID: 29980293 PMCID: PMC6084417 DOI: 10.1016/j.bpj.2018.06.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 05/02/2018] [Accepted: 06/11/2018] [Indexed: 01/06/2023] Open
Abstract
Experimental characterization of membrane proteins often requires solubilization. A recent approach is to use styrene-maleic acid (SMA) copolymers to isolate membrane proteins in nanometer-sized membrane disks, or so-called SMA lipid particles (SMALPs). The approach has the advantage of allowing direct extraction of proteins, keeping their native lipid environment. Despite the growing popularity of using SMALPs, the molecular mechanism behind the process remains poorly understood. Here, we unravel the molecular details of the nanodisk formation by using coarse-grained molecular dynamics simulations. We show how SMA copolymers bind to the lipid bilayer interface, driven by the hydrophobic effect. Due to the concerted action of multiple adsorbed copolymers, large membrane defects appear, including small, water-filled pores. The copolymers can stabilize the rim of these pores, leading to pore growth and membrane disruption. Although complete solubilization is not seen on the timescale of our simulations, self-assembly experiments show that small nanodisks are the thermodynamically preferred end state. Our findings shed light on the mechanism of SMALP formation and on their molecular structure. This can be an important step toward the design of optimized extraction tools for membrane protein research.
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Affiliation(s)
- Minmin Xue
- State Key Laboratory of Mechanics and Control of Mechanical Structures, Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China; Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, Groningen, the Netherlands; Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Lisheng Cheng
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing, People's Republic of China
| | - Ignacio Faustino
- Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, Groningen, the Netherlands; Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Wanlin Guo
- State Key Laboratory of Mechanics and Control of Mechanical Structures, Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Siewert J Marrink
- Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, Groningen, the Netherlands; Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands.
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50
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Sgro GG, Costa TRD. Cryo-EM Grid Preparation of Membrane Protein Samples for Single Particle Analysis. Front Mol Biosci 2018; 5:74. [PMID: 30131964 PMCID: PMC6090150 DOI: 10.3389/fmolb.2018.00074] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/10/2018] [Indexed: 11/26/2022] Open
Abstract
Recent advances in cryo-electron microscopy (cryo-EM) have made it possible to solve structures of biological macromolecules at near atomic resolution. Development of more stable microscopes, improved direct electron detectors and faster software for image processing has enabled structural solution of not only large macromolecular (megadalton range) complexes but also small (~60 kDa) proteins. As a result of the widespread use of the technique, we have also witnessed new developments of techniques for cryo-EM grid preparation of membrane protein samples. This includes new types of solubilization strategies that better stabilize these protein complexes and the development of new grid supports with proven efficacy in reducing the motion of the molecules during electron beam exposure. Here, we discuss the practicalities and recent challenges of membrane protein sample preparation and vitrification, as well as grid support and foil treatment in the context of the structure determination of protein complexes by single particle cryo-EM.
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Affiliation(s)
- Germán G. Sgro
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Tiago R. D. Costa
- Department of Life Sciences, Imperial College London, MRC Centre for Molecular Microbiology and Infection, London, United Kingdom
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