1
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Kellogg GE. Three-Dimensional Interaction Homology: Deconstructing Residue-Residue and Residue-Lipid Interactions in Membrane Proteins. Molecules 2024; 29:2838. [PMID: 38930903 PMCID: PMC11207109 DOI: 10.3390/molecules29122838] [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: 05/24/2024] [Revised: 06/09/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024] Open
Abstract
A method is described to deconstruct the network of hydropathic interactions within and between a protein's sidechain and its environment into residue-based three-dimensional maps. These maps encode favorable and unfavorable hydrophobic and polar interactions, in terms of spatial positions for optimal interactions, relative interaction strength, as well as character. In addition, these maps are backbone angle-dependent. After map calculation and clustering, a finite number of unique residue sidechain interaction maps exist for each backbone conformation, with the number related to the residue's size and interaction complexity. Structures for soluble proteins (~749,000 residues) and membrane proteins (~387,000 residues) were analyzed, with the latter group being subdivided into three subsets related to the residue's position in the membrane protein: soluble domain, core-facing transmembrane domain, and lipid-facing transmembrane domain. This work suggests that maps representing residue types and their backbone conformation can be reassembled to optimize the medium-to-high resolution details of a protein structure. In particular, the information encoded in maps constructed from the lipid-facing transmembrane residues appears to paint a clear picture of the protein-lipid interactions that are difficult to obtain experimentally.
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Affiliation(s)
- Glen E Kellogg
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298-0540, USA
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2
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Campuzano IDG. A Research Journey: Over a Decade of Denaturing and Native-MS Analyses of Hydrophobic and Membrane Proteins in Amgen Therapeutic Discovery. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2413-2431. [PMID: 37643331 DOI: 10.1021/jasms.3c00175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Membrane proteins and associated complexes currently comprise the majority of therapeutic targets and remain among the most challenging classes of proteins for analytical characterization. Through long-term strategic collaborations forged between industrial and academic research groups, there has been tremendous progress in advancing membrane protein mass spectrometry (MS) analytical methods and their concomitant application to Amgen therapeutic project progression. Herein, I will describe a detailed and personal account of how electrospray ionization (ESI) native mass spectrometry (nMS), ion mobility-MS (IM-MS), reversed phase liquid chromatographic mass spectrometry (RPLC-MS), high-throughput solid phase extraction mass spectrometry, and matrix-assisted laser desorption ionization mass spectrometry methods were developed, optimized, and validated within Amgen Research, and importantly, how these analytical methods were applied for membrane and hydrophobic protein analyses and ultimately therapeutic project support and progression. Additionally, I will discuss all the highly important and productive collaborative efforts, both internal Amgen and external academic, which were key in generating the samples, methods, and associated data described herein. I will also describe some early and previously unpublished nano-ESI (nESI) native-MS data from Amgen Research and the highly productive University of California Los Angeles (UCLA) collaboration. I will also present previously unpublished examples of real-life Amgen biotherapeutic membrane protein projects that were supported by all the MS (and IM) analytical techniques described herein. I will start by describing the initial nESI nMS experiments performed at Amgen in 2011 on empty nanodisc molecules, using a quadrupole time-of-flight MS, and how these experiments progressed on to the 15 Tesla Fourier transform ion cyclotron resonance MS at UCLA. Then described are monomeric and multimeric membrane protein data acquired in both nESI nMS and tandem-MS modes, using multiple methods of ion activation, resulting in dramatic spectral simplification. Also described is how we investigated the far less established and less published subject, that is denaturing RPLC-MS analysis of membrane proteins, and how we developed a highly robust and reproducible RPLC-MS method capable of effective separation of membrane proteins differing in only the presence or absence of an N-terminal post translational modification. Also described is the evolution of the aforementioned RPLC-MS method into a high-throughput solid phase extraction MS method. Finally, I will give my opinion on key developments and how the area of nMS of membrane proteins needs to evolve to a state where it can be applied within the biopharmaceutical research environment for routine therapeutic project support.
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Affiliation(s)
- Iain D G Campuzano
- Amgen Research, Center for Research Acceleration by Digital Innovation, Molecular Analytics, Thousand Oaks, California 91320, United States
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3
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AL Mughram MH, Catalano C, Herrington NB, Safo MK, Kellogg GE. 3D interaction homology: The hydrophobic residues alanine, isoleucine, leucine, proline and valine play different structural roles in soluble and membrane proteins. Front Mol Biosci 2023; 10:1116868. [PMID: 37056722 PMCID: PMC10086146 DOI: 10.3389/fmolb.2023.1116868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 02/20/2023] [Indexed: 03/30/2023] Open
Abstract
The aliphatic hydrophobic amino acid residues—alanine, isoleucine, leucine, proline and valine—are among the most common found in proteins. Their structural role in proteins is seemingly obvious: engage in hydrophobic interactions to stabilize secondary, and to a lesser extent, tertiary and quaternary structure. However, favorable hydrophobic interactions involving the sidechains of these residue types are generally less significant than the unfavorable set arising from interactions with polar atoms. Importantly, the constellation of interactions between residue sidechains and their environments can be recorded as three-dimensional maps that, in turn, can be clustered. The clustered average map sets compose a library of interaction profiles encoding interaction strengths, interaction types and the optimal 3D position for the interacting partners. This library is backbone angle-dependent and suggests solvent and lipid accessibility for each unique interaction profile. In this work, in addition to analysis of soluble proteins, a large set of membrane proteins that contained optimized artificial lipids were evaluated by parsing the structures into three distinct components: soluble extramembrane domain, lipid facing transmembrane domain, core transmembrane domain. The aliphatic residues were extracted from each of these sets and passed through our calculation protocol. Notable observations include: the roles of aliphatic residues in soluble proteins and in the membrane protein’s soluble domains are nearly identical, although the latter are slightly more solvent accessible; by comparing maps calculated with sidechain-lipid interactions to maps ignoring those interactions, the potential extent of residue-lipid and residue-interactions can be assessed and likely exploited in structure prediction and modeling; amongst these residue types, the levels of lipid engagement show isoleucine as the most engaged, while the other residues are largely interacting with neighboring helical residues.
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Affiliation(s)
- Mohammed H. AL Mughram
- Department of Medicinal Chemistry and the Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, United States
| | - Claudio Catalano
- Department of Medicinal Chemistry and the Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, United States
| | - Noah B. Herrington
- Department of Medicinal Chemistry and the Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, United States
| | - Martin K. Safo
- Department of Medicinal Chemistry and the Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, United States
| | - Glen E. Kellogg
- Department of Medicinal Chemistry and the Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, United States
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA, United States
- *Correspondence: Glen E. Kellogg,
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4
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Higgins AJ, Flynn AJ, Marconnet A, Musgrove LJ, Postis VLG, Lippiat JD, Chung CW, Ceska T, Zoonens M, Sobott F, Muench SP. Cycloalkane-modified amphiphilic polymers provide direct extraction of membrane proteins for CryoEM analysis. Commun Biol 2021; 4:1337. [PMID: 34824357 PMCID: PMC8617058 DOI: 10.1038/s42003-021-02834-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 10/27/2021] [Indexed: 12/30/2022] Open
Abstract
Membrane proteins are essential for cellular growth, signalling and homeostasis, making up a large proportion of therapeutic targets. However, the necessity for a solubilising agent to extract them from the membrane creates challenges in their structural and functional study. Although amphipols have been very effective for single-particle electron cryo-microscopy (cryoEM) and mass spectrometry, they rely on initial detergent extraction before exchange into the amphipol environment. Therefore, circumventing this pre-requirement would be a big advantage. Here we use an alternative type of amphipol: a cycloalkane-modified amphiphile polymer (CyclAPol) to extract Escherichia coli AcrB directly from the membrane and demonstrate that the protein can be isolated in a one-step purification with the resultant cryoEM structure achieving 3.2 Å resolution. Together this work shows that cycloalkane amphipols provide a powerful approach for the study of membrane proteins, allowing native extraction and high-resolution structure determination by cryoEM.
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Affiliation(s)
- Anna J Higgins
- School of Biomedical Sciences, Faculty of Biological Sciences & Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Alex J Flynn
- School of Biomedical Sciences, Faculty of Biological Sciences & Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Anaïs Marconnet
- Université de Paris, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, F-75005, Paris, France
- Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild pour le dévelopement de la recherche scientifique, F-75005, Paris, France
| | - Laura J Musgrove
- School of Biomedical Sciences, Faculty of Biological Sciences & Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Vincent L G Postis
- School of Biomedical Sciences, Faculty of Biological Sciences & Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
- Wellcome Centre for Anti-Infectives Research, Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, DD1 5EH, UK
| | - Jonathan D Lippiat
- School of Biomedical Sciences, Faculty of Biological Sciences & Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Chun-Wa Chung
- GlaxoSmithKline, Gunnels Wood Road, Stevenage, SG1 2NY, UK
| | | | - Manuela Zoonens
- Université de Paris, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, F-75005, Paris, France.
- Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild pour le dévelopement de la recherche scientifique, F-75005, Paris, France.
| | - Frank Sobott
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
| | - Stephen P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences & Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
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5
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TMEM116 is required for lung cancer cell motility and metastasis through PDK1 signaling pathway. Cell Death Dis 2021; 12:1086. [PMID: 34789718 PMCID: PMC8599864 DOI: 10.1038/s41419-021-04369-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/18/2021] [Accepted: 10/29/2021] [Indexed: 12/17/2022]
Abstract
Transmembrane protein (TMEM) is a family of protein that spans cytoplasmic membranes and allows cell-cell and cell-environment communication. Dysregulation of TMEMs has been observed in multiple cancers. However, little is known about TMEM116 in cancer development. In this study, we demonstrate that TMEM116 is highly expressed in non-small-cell lung cancer (NSCLC) tissues and cell lines. Inactivation of TMEM116 reduced cell proliferation, migration and invasiveness of human cancer cells and suppressed A549 induced tumor metastasis in mouse lungs. In addition, TMEM116 deficiency inhibited PDK1-AKT-FOXO3A signaling pathway, resulting in accumulation of TAp63, while activation of PDK1 largely reversed the TMEM116 deficiency induced defects in cancer cell motility, migration and invasive. Together, these results demonstrate that TMEM116 is a critical integrator of oncogenic signaling in cancer metastasis.
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6
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Expression, Purification and Crystallization of Asrij, A Novel Scaffold Transmembrane Protein. J Membr Biol 2021; 254:65-74. [PMID: 33433647 DOI: 10.1007/s00232-020-00166-7] [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: 10/23/2020] [Accepted: 12/17/2020] [Indexed: 10/22/2022]
Abstract
Asrij/OCIAD1 is a scaffold transmembrane protein belonging to the Ovarian Carcinoma Immunoreactive Antigen Domain containing protein family. In Drosophila and mouse models, Asrij localizes at the endosomal and mitochondrial membrane and is shown to regulate the stemness of hematopoietic stem cells. Interaction of Asrij with ADP Ribosylation Factor 1 (Arf1) is shown to be crucial for hematopoietic niche function and prohemocyte maintenance. Here, we report the heterologous expression, standardization of detergents and purification methodologies for crystallization of Asrij/OCIAD1. To probe the activity of bacterially expressed Asrij, we developed a protein complementation assay and conclusively show that Asrij and Arf1 physically interact. Further, we find that sophorolipids improve the solubility and monodispersibility of Asrij. Hence, we propose that sophorolipids could be novel additives for stabilization of membrane proteins. To our knowledge, this is the first study detailing methodology for the production and crystallization of a heterologously expressed scaffold membrane protein and will be widely applicable to understand membrane protein structure and function.
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7
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Mariano G, Farthing RJ, Lale-Farjat SLM, Bergeron JRC. Structural Characterization of SARS-CoV-2: Where We Are, and Where We Need to Be. Front Mol Biosci 2020; 7:605236. [PMID: 33392262 PMCID: PMC7773825 DOI: 10.3389/fmolb.2020.605236] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/22/2020] [Indexed: 01/18/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread in humans in almost every country, causing the disease COVID-19. Since the start of the COVID-19 pandemic, research efforts have been strongly directed towards obtaining a full understanding of the biology of the viral infection, in order to develop a vaccine and therapeutic approaches. In particular, structural studies have allowed to comprehend the molecular basis underlying the role of many of the SARS-CoV-2 proteins, and to make rapid progress towards treatment and preventive therapeutics. Despite the great advances that have been provided by these studies, many knowledge gaps on the biology and molecular basis of SARS-CoV-2 infection still remain. Filling these gaps will be the key to tackle this pandemic, through development of effective treatments and specific vaccination strategies.
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Affiliation(s)
- Giuseppina Mariano
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Rebecca J. Farthing
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | | | - Julien R. C. Bergeron
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
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8
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Durham RJ, Latham DR, Sanabria H, Jayaraman V. Structural Dynamics of Glutamate Signaling Systems by smFRET. Biophys J 2020; 119:1929-1936. [PMID: 33096078 PMCID: PMC7732771 DOI: 10.1016/j.bpj.2020.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/06/2020] [Accepted: 10/13/2020] [Indexed: 12/19/2022] Open
Abstract
Single-molecule Förster resonance energy transfer (smFRET) is a powerful technique for investigating the structural dynamics of biological macromolecules. smFRET reveals the conformational landscape and dynamic changes of proteins by building on the static structures found using cryo-electron microscopy, x-ray crystallography, and other methods. Combining smFRET with static structures allows for a direct correlation between dynamic conformation and function. Here, we discuss the different experimental setups, fluorescence detection schemes, and data analysis strategies that enable the study of structural dynamics of glutamate signaling across various timescales. We illustrate the versatility of smFRET by highlighting studies of a wide range of questions, including the mechanism of activation and transport, the role of intrinsically disordered segments, and allostery and cooperativity between subunits in biological systems responsible for glutamate signaling.
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Affiliation(s)
- Ryan J Durham
- University of Texas Health Science Center at Houston, Houston, Texas
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9
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Di Mauro GM, Hardin NZ, Ramamoorthy A. Lipid-nanodiscs formed by paramagnetic metal chelated polymer for fast NMR data acquisition. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2020; 1862:183332. [PMID: 32360741 PMCID: PMC7340147 DOI: 10.1016/j.bbamem.2020.183332] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/21/2020] [Accepted: 04/27/2020] [Indexed: 02/07/2023]
Abstract
Lipid-nanodiscs have been shown to be an exciting innovation as a membrane-mimicking system for studies on membrane proteins by a variety of biophysical techniques, including NMR spectroscopy. Although NMR spectroscopy is unique in enabling the atomic-resolution investigation of dynamic structures of membrane-associated molecules, it, unfortunately, suffers from intrinsically low sensitivity. The long data acquisition often used to enhance the sensitivity is not desirable for sensitive membrane proteins. Instead, paramagnetic relaxation enhancement (PRE) has been used to reduce NMR data acquisition time or to reduce the amount of sample required to acquire an NMR spectra. However, the PRE approach involves the introduction of external paramagnetic probes in the system, which can induce undesired changes in the sample and on the observed NMR spectra. For example, the addition of paramagnetic ions, as frequently used, can denature the protein via direct interaction and also through sample heating. In this study, we show how the introduction of paramagnetic tags on the outer belt of polymer-nanodiscs can be used to speed-up data acquisition by significantly reducing the spin-lattice relaxation (T1) times with minimum-to-no alteration of the spectral quality. Our results also demonstrate the feasibility of using different types of paramagnetic ions (Eu3+, Gd3+, Dy3+, Er3+, Yb3+) for NMR studies on lipid-nanodiscs. Experimental results characterizing the formation of lipid-nanodiscs by the metal-chelated polymer, and their increased tolerance toward metal ions are also reported.
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Affiliation(s)
- Giacomo M Di Mauro
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Nathaniel Z Hardin
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Biophysics and Chemistry Department, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Macromolecular Science and Engineering, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Biomedical Engineering, The University of Michigan, Ann Arbor, MI 48109-1055, USA.
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10
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Bozelli JC, Epand RM. Membrane Shape and the Regulation of Biological Processes. J Mol Biol 2020; 432:5124-5136. [DOI: 10.1016/j.jmb.2020.03.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 01/06/2023]
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11
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Cole BA, Johnson RM, Dejakaisaya H, Pilati N, Fishwick CWG, Muench SP, Lippiat JD. Structure-Based Identification and Characterization of Inhibitors of the Epilepsy-Associated K Na1.1 (KCNT1) Potassium Channel. iScience 2020; 23:101100. [PMID: 32408169 PMCID: PMC7225746 DOI: 10.1016/j.isci.2020.101100] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 04/02/2020] [Accepted: 04/21/2020] [Indexed: 12/23/2022] Open
Abstract
Drug-resistant epileptic encephalopathies of infancy have been associated with KCNT1 gain-of-function mutations, which increase the activity of KNa1.1 sodium-activated potassium channels. Pharmacological inhibition of hyperactive KNa1.1 channels by quinidine has been proposed as a stratified treatment, but mostly this has not been successful, being linked to the low potency and lack of specificity of the drug. Here we describe the use of a previously determined cryo-electron microscopy-derived KNa1.1 structure and mutational analysis to identify how quinidine binds to the channel pore and, using computational methods, screened for compounds predicated to bind to this site. We describe six compounds that inhibited KNa1.1 channels with low- and sub-micromolar potencies, likely also through binding in the intracellular pore vestibule. In hERG inhibition and cytotoxicity assays, two compounds were ineffective. These may provide starting points for the development of new pharmacophores and could become tool compounds to study this channel further.
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Affiliation(s)
- Bethan A Cole
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Rachel M Johnson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Hattapark Dejakaisaya
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Nadia Pilati
- Autifony Srl, Istituto di Ricerca Pediatrica Citta' della Speranza, Corso Stati Uniti, 4f, 35127 Padova, Italy
| | - Colin W G Fishwick
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | - Stephen P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Jonathan D Lippiat
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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12
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Dang AT, He W, Ivey DB, Coleman MA, Kuhl TL. Lipid and Protein Transfer between Nanolipoprotein Particles and Supported Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:12071-12078. [PMID: 31442053 PMCID: PMC7024587 DOI: 10.1021/acs.langmuir.9b01288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A nanolipoprotein particle (NLP) is a lipid bilayer disc stabilized by two amphipathic "scaffold" apolipoproteins. It has been most notably utilized as a tool for solubilizing a variety of membrane proteins while preserving structural and functional properties. Transfer of functional proteins from NLPs into model membrane systems such as supported lipid bilayers (SLBs) would enable new opportunities, for example, two-dimensional protein crystallization and studies on protein-protein interactions. This work used fluorescence microscopy and atomic force microscopy to investigate the interaction between NLPs and SLBs. When incubated with SLBs, NLPs were found to spontaneously deliver lipid and protein cargo. The impact of membrane composition on lipid exchange was explored, revealing a positive correlation between the magnitude of lipid transfer and concentration of defects in the target SLB. Incorporation of lipids capable of binding specifically to polyhistidine tags encoded into the apolipoproteins also boosted transfer of NLP cargo. Optimal conditions for lipid and protein delivery from NLPs to SLBs are proposed based on interaction mechanisms.
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Affiliation(s)
- Amanda T. Dang
- Department of Materials Science and Engineering, University of California, Davis CA 95616
| | - Wei He
- Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Daniela B. Ivey
- Department of Chemical Engineering, University of California, Davis CA 95616
| | | | - Tonya L. Kuhl
- Department of Chemical Engineering, University of California, Davis CA 95616
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13
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Marx S, Dal Maso T, Chen JW, Bury M, Wouters J, Michiels C, Le Calvé B. Transmembrane (TMEM) protein family members: Poorly characterized even if essential for the metastatic process. Semin Cancer Biol 2019; 60:96-106. [PMID: 31454669 DOI: 10.1016/j.semcancer.2019.08.018] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 01/02/2023]
Abstract
The majority of cancer-associated deaths are related to secondary tumor formation. This multistep process involves the migration of cancer cells to anatomically distant organs. Metastasis formation relies on cancer cell dissemination and survival in the circulatory system, as well as adaptation to the new tissue notably through genetic and/or epigenetic alterations. A large number of proteins are clearly identified to play a role in the metastatic process but the structures and modes of action of these proteins are essentially unknown or poorly described. In this review, we detail the involvement of members of the transmembrane (TMEM) protein family in the formation of metastases or in the mechanisms leading to cancer cell dissemination such as migration and extra-cellular matrix remodelling. While the phenotype associated with TMEM over or down-expression is clear, the mechanisms by which these proteins allow cancer cell spreading remain, for most of them, unclear. In parallel, the 3D structures of these proteins are presented. Moreover, we proposed that TMEM proteins could be used as prognostic markers in different types of cancers and could represent potential targets for cancer treatment. A better understanding of this heterogeneous family of poorly characterized proteins thus opens perspectives for better cancer patient care.
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Affiliation(s)
- Sébastien Marx
- Department of Chemistry, NAmur MEdicine & Drug Innovation Center (NAMEDIC-NARILIS), University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| | - Thomas Dal Maso
- Department of Chemistry, NAmur MEdicine & Drug Innovation Center (NAMEDIC-NARILIS), University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| | - Jia-Wei Chen
- URBC - NARILIS, University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| | - Marina Bury
- de Duve Institute, 75 Avenue Hippocrate, 1200 Bruxelles, Belgium
| | - Johan Wouters
- Department of Chemistry, NAmur MEdicine & Drug Innovation Center (NAMEDIC-NARILIS), University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| | - Carine Michiels
- URBC - NARILIS, University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| | - Benjamin Le Calvé
- URBC - NARILIS, University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium.
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14
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Mitra G. Application of native mass spectrometry in studying intrinsically disordered proteins: A special focus on neurodegenerative diseases. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:140260. [PMID: 31382021 DOI: 10.1016/j.bbapap.2019.07.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/30/2019] [Accepted: 07/31/2019] [Indexed: 12/26/2022]
Abstract
Intrinsically disordered proteins (IDPs) are integral part of the proteome, regulating vital biological processes. Such proteins gained further visibility due to their key role in neurodegenerative diseases and cancer. IDPs however, escape structural characterization by traditional biophysical tools owing to their extreme flexibility and heterogeneity. In this review, we discuss the advantages of native mass spectrometry (MS) in analysing the atypical conformational dynamics of IDPs and recent advances made in the field. Especially, MS studies unravelling the conformational facets of IDPs involved in neurodegenerative diseases are highlighted. The limitations and the future promises of native MS while studying IDPs have been discussed.
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Affiliation(s)
- Gopa Mitra
- Clinical Proteomics Unit, Division of Molecular Medicine, St. John's Research Institute, St. John's National Academy of Health Sciences, 100 Feet Road, Koramangala, Bangalore 560034, Karnataka, India.
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15
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Greene D, Qi R, Nguyen R, Qiu T, Luo R. Heterogeneous Dielectric Implicit Membrane Model for the Calculation of MMPBSA Binding Free Energies. J Chem Inf Model 2019; 59:3041-3056. [PMID: 31145610 PMCID: PMC7197397 DOI: 10.1021/acs.jcim.9b00363] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Membrane-bound protein receptors are a primary biological drug target, but the computational analysis of membrane proteins has been limited. In order to improve molecular mechanics Poisson-Boltzmann surface area (MMPBSA) binding free energy calculations for membrane protein-ligand systems, we have optimized a new heterogeneous dielectric implicit membrane model, with respect to free energy simulations in explicit membrane and explicit water, and implemented it into the Amber software suite. This new model supersedes our previous uniform, single dielectric implicit membrane model by allowing the dielectric constant to vary with depth within the membrane. We calculated MMPBSA binding free energies for the human purinergic platelet receptor (P2Y12R) and two of the muscarinic acetylcholine receptors (M2R and M3R) bound to various antagonist ligands using both membrane models, and we found that the heterogeneous dielectric membrane model has a stronger correlation with experimental binding affinities compared to the older model under otherwise identical conditions. This improved membrane model increases the utility of MMPBSA calculations for the rational design and improvement of future drug candidates.
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16
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Abstract
For mechanical force to induce changes in cellular behaviors, two main processes are inevitable; perception of the force and response to it. Perception of mechanical force by cells, or mechanosensing, requires mechanical force-induced conformational changes in mechanosensors. For this, at least one end of the mechanosensors should be anchored to relatively fixed structures, such as extracellular matrices or the cytoskeletons, while the other end should be pulled along the direction of the mechanical force. Alternatively, mechanosensors may be positioned in lipid bilayers, so that conformational changes in the embedded sensors can be induced by mechanical force-driven tension in the lipid bilayer. Responses to mechanical force by cells, or mechanotransduction, require translation of such mechanical force-induced conformational changes into biochemical signaling. For this, protein-protein interactions or enzymatic activities of mechanosensors should be modulated in response to force-induced structural changes. In the last decade, several molecules that met the required criteria of mechanosensors have been identified and proven to directly sense mechanical force. The present review introduces examples of such mechanosensors and summarizes their mechanisms of action.
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Affiliation(s)
- Chul-Gyun Lim
- Department of Life Sciences, Korea University, Seoul 02841, Korea
| | - Jiyoung Jang
- Department of Life Sciences, Korea University, Seoul 02841, Korea
| | - Chungho Kim
- Department of Life Sciences, Korea University, Seoul 02841, Korea
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17
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Young D, Pedre B, Ezeriņa D, De Smet B, Lewandowska A, Tossounian MA, Bodra N, Huang J, Astolfi Rosado L, Van Breusegem F, Messens J. Protein Promiscuity in H 2O 2 Signaling. Antioxid Redox Signal 2019; 30:1285-1324. [PMID: 29635930 DOI: 10.1089/ars.2017.7013] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
SIGNIFICANCE Decrypting the cellular response to oxidative stress relies on a comprehensive understanding of the redox signaling pathways stimulated under oxidizing conditions. Redox signaling events can be divided into upstream sensing of oxidants, midstream redox signaling of protein function, and downstream transcriptional redox regulation. Recent Advances: A more and more accepted theory of hydrogen peroxide (H2O2) signaling is that of a thiol peroxidase redox relay, whereby protein thiols with low reactivity toward H2O2 are instead oxidized through an oxidative relay with thiol peroxidases. CRITICAL ISSUES These ultrareactive thiol peroxidases are the upstream redox sensors, which form the first cellular port of call for H2O2. Not all redox-regulated interactions between thiol peroxidases and cellular proteins involve a transfer of oxidative equivalents, and the nature of redox signaling is further complicated through promiscuous functions of redox-regulated "moonlighting" proteins, of which the precise cellular role under oxidative stress can frequently be obscured by "polygamous" interactions. An ultimate goal of redox signaling is to initiate a rapid response, and in contrast to prokaryotic oxidant-responsive transcription factors, mammalian systems have developed redox signaling pathways, which intersect both with kinase-dependent activation of transcription factors, as well as direct oxidative regulation of transcription factors through peroxiredoxin (Prx) redox relays. FUTURE DIRECTIONS We highlight that both transcriptional regulation and cell fate can be modulated either through oxidative regulation of kinase pathways, or through distinct redox-dependent associations involving either Prxs or redox-responsive moonlighting proteins with functional promiscuity. These protein associations form systems of crossregulatory networks with multiple nodes of potential oxidative regulation for H2O2-mediated signaling.
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Affiliation(s)
- David Young
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Brandan Pedre
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Daria Ezeriņa
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Barbara De Smet
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Aleksandra Lewandowska
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Maria-Armineh Tossounian
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Nandita Bodra
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Jingjing Huang
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Leonardo Astolfi Rosado
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Frank Van Breusegem
- 2 Brussels Center for Redox Biology, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Joris Messens
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
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18
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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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19
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Ravula T, Hardin NZ, Ramamoorthy A. Polymer nanodiscs: Advantages and limitations. Chem Phys Lipids 2019; 219:45-49. [PMID: 30707909 PMCID: PMC6497063 DOI: 10.1016/j.chemphyslip.2019.01.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/25/2019] [Accepted: 01/28/2019] [Indexed: 11/29/2022]
Abstract
There is considerable interest in the development of membrane mimetics to study the structure, dynamics and function of membrane proteins. Polymer nanodiscs have been useful as a membrane mimetic by not only providing a native-like membrane environment, but also have the ability to extract the desired membrane protein directly from the cell membrane. In spite of such great potential, polymer nanodiscs have their disadvantages including lack of size control and instability at low pH and with divalent metals. In this review, we discuss how these limitations have been overcome by simple modifications of synthetic polymers commonly used to form nanodiscs. Recently, size control has been achieved using an ethanolamine functionalization of a low molecular weight polymer. This size control enabled the use of polymer-based lipid-nanodiscs in solution NMR and macro-nanodiscs in solid-state NMR applications. The introduction of quaternary ammonium functional groups has been shown to improve the stability in the presence of low pH and divalent metal ions, forming highly monodispersed nanodiscs. The polymer charge has been shown to play a significant role on the reconstitution of membrane proteins due to the high charge density on the nanodisc's belt. These recent developments have expanded the applications of polymer nanodiscs to study the membrane proteins using wide variety of techniques including NMR, Cryo-EM and other biophysical techniques.
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Affiliation(s)
- Thirupathi Ravula
- Biophysics Program, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Nathaniel Z Hardin
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Biomedical Engineering, The University of Michigan, Ann Arbor, MI 48109-1055, USA; Macromolecular Science and Engineering, The University of Michigan, Ann Arbor, MI 48109-1055, USA.
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20
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Perry TN, Souabni H, Rapisarda C, Fronzes R, Giusti F, Popot JL, Zoonens M, Gubellini F. BAmSA: Visualising transmembrane regions in protein complexes using biotinylated amphipols and electron microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:466-477. [DOI: 10.1016/j.bbamem.2018.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 12/30/2022]
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21
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DeMarco KR, Bekker S, Vorobyov I. Challenges and advances in atomistic simulations of potassium and sodium ion channel gating and permeation. J Physiol 2018; 597:679-698. [PMID: 30471114 DOI: 10.1113/jp277088] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 10/15/2018] [Indexed: 12/19/2022] Open
Abstract
Ion channels are implicated in many essential physiological events such as electrical signal propagation and cellular communication. The advent of K+ and Na+ ion channel structure determination has facilitated numerous investigations of molecular determinants of their behaviour. At the same time, rapid development of computer hardware and molecular simulation methodologies has made computational studies of large biological molecules in all-atom representation tractable. The concurrent evolution of experimental structural biology with biomolecular computer modelling has yielded mechanistic details of fundamental processes unavailable through experiments alone, such as ion conduction and ion channel gating. This review is a short survey of the atomistic computational investigations of K+ and Na+ ion channels, focusing on KcsA and several voltage-gated channels from the KV and NaV families, which have garnered many successes and engendered several long-standing controversies regarding the nature of their structure-function relationship. We review the latest advancements and challenges facing the field of molecular modelling and simulation regarding the structural and energetic determinants of ion channel function and their agreement with experimental observations.
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Affiliation(s)
- Kevin R DeMarco
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, CA, USA.,Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Slava Bekker
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, CA, USA.,Chemistry Department, American River College, Sacramento, CA, USA
| | - Igor Vorobyov
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, CA, USA.,Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
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22
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Siligardi G, Hughes CS, Hussain R. Characterisation of sensor kinase by CD spectroscopy: golden rules and tips. Biochem Soc Trans 2018; 46:1627-1642. [PMID: 30514767 PMCID: PMC6299240 DOI: 10.1042/bst20180222] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/19/2018] [Accepted: 09/21/2018] [Indexed: 01/22/2023]
Abstract
This is a review that describes the golden rules and tips on how to characterise the molecular interactions of membrane sensor kinase proteins with ligands using mainly circular dichroism (CD) spectroscopy. CD spectroscopy is essential for this task as any conformational change observed in the far-UV (secondary structures (α-helix, β-strands, poly-proline of type II, β-turns, irregular and folding) and near-UV regions [local environment of the aromatic side-chains of amino acid residues (Phe, Tyr and Trp) and ligands (drugs) and prosthetic groups (porphyrins, cofactors and coenzymes (FMN, FAD, NAD))] upon ligand addition to the protein can be used to determine qualitatively and quantitatively ligand-binding interactions. Advantages of using CD versus other techniques will be discussed. The difference CD spectra of the protein-ligand mixtures calculated subtracting the spectra of the ligand at various molar ratios can be used to determine the type of conformational changes induced by the ligand in terms of the estimated content of the various elements of protein secondary structure. The highly collimated microbeam and high photon flux of Diamond Light Source B23 beamline for synchrotron radiation circular dichroism (SRCD) enable the use of minimal amount of membrane proteins (7.5 µg for a 0.5 mg/ml solution) for high-throughput screening. Several examples of CD titrations of membrane proteins with a variety of ligands are described herein including the protocol tips that would guide the choice of the appropriate parameters to conduct these titrations by CD/SRCD in the best possible way.
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Affiliation(s)
- Giuliano Siligardi
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire, U.K
| | - Charlotte S Hughes
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire, U.K
| | - Rohanah Hussain
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire, U.K.
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23
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Ravula T, Hardin NZ, Di Mauro GM, Ramamoorthy A. Styrene maleic acid derivates to enhance the applications of bio-inspired polymer based lipid-nanodiscs. Eur Polym J 2018; 108:597-602. [PMID: 31105326 PMCID: PMC6516473 DOI: 10.1016/j.eurpolymj.2018.09.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Membrane mimetics are essential to study the structure, dynamics and function of membrane-associated proteins by biophysical and biochemical approaches. Among various membrane mimetics that have been developed and demonstrated for studies on membrane proteins, lipid nanodiscs are the latest developments in the field and are increasingly used for various applications. While lipid-nanodiscs can be formed using an amphipathic membrane scaffold protein (MSP), peptide, or synthetic polymer, the synthetic polymer based nanodiscs exhibit unique advantages because of the ability to functionalize them for various applications. In addition to the use of synthetic polymers to extract membrane proteins directly from the cell membranes, recent advances in the development of polymers used for nanodiscs formation are attracting new attention to the field of nanodiscs technology. Here we review the developments of novel polymer modifications that overcome the current limitations and enhance the applications of polymer based nanodiscs to a wider variety of biophysical techniques used to study membrane proteins. A summary of the functionalization of poly(Styrene-co-Maleic Acid), SMA, polymers developed by our research and their advantages are also covered in this review article.
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Affiliation(s)
- Thirupathi Ravula
- Biophysics Program and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Nathaniel. Z Hardin
- Biophysics Program and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Giacomo M. Di Mauro
- Biophysics Program and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
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24
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Raeeszadeh-Sarmazdeh M, Patel N, Cruise S, Owen L, O'Neill H, Boder ET. Identifying Stable Fragments of Arabidopsis thaliana Cellulose Synthase Subunit 3 by Yeast Display. Biotechnol J 2018; 14:e1800353. [PMID: 30171735 DOI: 10.1002/biot.201800353] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/08/2018] [Indexed: 12/22/2022]
Abstract
Determining structures of large, complex proteins remains challenging, especially for transmembrane proteins, as the protein size increases. Arabidopsis thaliana cellulose synthesis complex is a large, multimeric complex located in the plant cell membrane that synthesizes cellulose microfibrils in the plant cell wall. Despite the biological and economic importance of cellulose and therefore cellulose synthesis, many aspects of the cellulase synthase complex (CSC) structure and function are still unknown. Here, yeast surface display (YSD) is used to determine the full-length expression of A. thaliana cellulose synthase 3 (AtCesA3) fragments. The level of stably-folded AtCesA3 fragments displayed on the yeast surface are determined using flow cytometric analysis of differential surface expression of epitopes flanking the AtCesA3 fragment. This technique provides a fast and simple method for examining folding and expression of protein domains and fragments of complex proteins.
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Affiliation(s)
- Maryam Raeeszadeh-Sarmazdeh
- Department of Chemical and Biomolecular Engineering, University of Tennessee at Knoxville, Knoxville, TN 37996
| | - Nikhil Patel
- Department of Chemical and Biomolecular Engineering, University of Tennessee at Knoxville, Knoxville, TN 37996
| | - Sarah Cruise
- Department of Chemical and Biomolecular Engineering, University of Tennessee at Knoxville, Knoxville, TN 37996
| | - Leila Owen
- Department of Chemical and Biomolecular Engineering, University of Tennessee at Knoxville, Knoxville, TN 37996
| | - Hugh O'Neill
- Center for Structural Molecular Biology and Neutron Scsattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Eric T Boder
- Department of Chemical and Biomolecular Engineering, University of Tennessee at Knoxville, Knoxville, TN 37996
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25
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Pichler H, Emmerstorfer-Augustin A. Modification of membrane lipid compositions in single-celled organisms – From basics to applications. Methods 2018; 147:50-65. [DOI: 10.1016/j.ymeth.2018.06.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/18/2018] [Accepted: 06/16/2018] [Indexed: 12/12/2022] Open
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26
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Dias Mirandela G, Tamburrino G, Ivanović MT, Strnad FM, Byron O, Rasmussen T, Hoskisson PA, Hub JS, Zachariae U, Gabel F, Javelle A. Merging In-Solution X-ray and Neutron Scattering Data Allows Fine Structural Analysis of Membrane-Protein Detergent Complexes. J Phys Chem Lett 2018; 9:3910-3914. [PMID: 29939747 DOI: 10.1021/acs.jpclett.8b01598] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In-solution small-angle X-ray and neutron scattering (SAXS/SANS) have become popular methods to characterize the structure of membrane proteins, solubilized by either detergents or nanodiscs. SANS studies of protein-detergent complexes usually require deuterium-labeled proteins or detergents, which in turn often lead to problems in their expression or purification. Here, we report an approach whose novelty is the combined analysis of SAXS and SANS data from an unlabeled membrane protein complex in solution in two complementary ways. First, an explicit atomic analysis, including both protein and detergent molecules, using the program WAXSiS, which has been adapted to predict SANS data. Second, the use of MONSA which allows one to discriminate between detergent head- and tail-groups in an ab initio approach. Our approach is readily applicable to any detergent-solubilized protein and provides more detailed structural information on protein-detergent complexes from unlabeled samples than SAXS or SANS alone.
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Affiliation(s)
- Gaëtan Dias Mirandela
- Strathclyde Institute of Pharmacy and Biomedical Sciences , University of Strathclyde , Glasgow , G4 0RE , United Kingdom
| | - Giulia Tamburrino
- Computational Biology, School of Life Sciences , University of Dundee , Dundee , DD1 5EH , United Kingdom
- Physics, School of Science and Engineering , University of Dundee , Dundee , DD1 4NH , United Kingdom
| | - Miloš T Ivanović
- Theoretical Physics , Saarland University , Campus E2 6 , 66123 Saarbrücken , Germany
| | - Felix M Strnad
- Institute for Microbiology and Genetics , University of Goettingen , Justus-von-Liebig-Weg 11 , 37077 Göttingen , Germany
| | - Olwyn Byron
- School of Life Sciences, College of Medical, Veterinary and Life Sciences , University of Glasgow , Glasgow , G12 8QQ , United Kingdom
| | - Tim Rasmussen
- School of Medical Sciences , University of Aberdeen , Foresterhill, Aberdeen AB25 2ZD , United Kingdom
| | - Paul A Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical Sciences , University of Strathclyde , Glasgow , G4 0RE , United Kingdom
| | - Jochen S Hub
- Theoretical Physics , Saarland University , Campus E2 6 , 66123 Saarbrücken , Germany
| | - Ulrich Zachariae
- Computational Biology, School of Life Sciences , University of Dundee , Dundee , DD1 5EH , United Kingdom
- Physics, School of Science and Engineering , University of Dundee , Dundee , DD1 4NH , United Kingdom
| | - Frank Gabel
- Institut Laue-Langevin , 71 Avenue des Martyrs 38042 Grenoble , France
- University of Grenoble Alpes, CEA, CNRS, IBS , 38000 Grenoble , France
| | - Arnaud Javelle
- Strathclyde Institute of Pharmacy and Biomedical Sciences , University of Strathclyde , Glasgow , G4 0RE , United Kingdom
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27
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Dutta M. Recent Advances in Single Particle Cryo-electron Microscopy and Cryo-electron Tomography to Determine the Structures of Biological Macromolecules. J Indian Inst Sci 2018. [DOI: 10.1007/s41745-018-0087-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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28
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Reading E. Structural Mass Spectrometry of Membrane Proteins within Their Native Lipid Environments. Chemistry 2018; 24:13391-13398. [PMID: 29672954 DOI: 10.1002/chem.201801556] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Indexed: 01/22/2023]
Abstract
Mass spectrometry has emerged as an important structural biology tool for understanding membrane protein structure, function, and dynamics. Generally, structural mass spectrometry of membrane proteins has been performed on purified or reconstituted systems which lack the native lipid membrane and cellular environments. However, there has been progress in the use and adaptations of these methods for probing membrane proteins within increasingly more native contexts. In this Concept article the use and utility of structural mass spectrometry techniques for studying membrane proteins within native environments are highlighted.
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Affiliation(s)
- Eamonn Reading
- Department of Chemistry, King's College London, 7 Trinity Street, SE1 1DB, London, UK
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29
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De Biasio A, Ibáñez de Opakua A, Bostock MJ, Nietlispach D, Diercks T, Blanco FJ. A generalized approach for NMR studies of lipid-protein interactions based on sparse fluorination of acyl chains. Chem Commun (Camb) 2018; 54:7306-7309. [PMID: 29905339 DOI: 10.1039/c8cc02483a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sparse lipid fluorination enhances the lipids' 1H signal dispersion, enables clean molecular distinction by 19F NMR, and evinces micelle insertion of proteins via fluorine-induced signal shifts. We present a minimal fluorination scheme, and illustrate the concept on di-(4-fluoro)-heptanoylphosphatidylcholine micelles and solubilised seven-helix transmembrane pSRII protein.
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30
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Lu Y, Goodson C, Blankenship RE, Gross ML. Primary and Higher Order Structure of the Reaction Center from the Purple Phototrophic Bacterium Blastochloris viridis: A Test for Native Mass Spectrometry. J Proteome Res 2018; 17:1615-1623. [PMID: 29466012 PMCID: PMC5911391 DOI: 10.1021/acs.jproteome.7b00897] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction center (RC) from the phototrophic bacterium Blastochloris viridis was the first integral membrane protein complex to have its structure determined by X-ray crystallography and has been studied extensively since then. It is composed of four protein subunits, H, M, L, and C, as well as cofactors, including bacteriopheophytin (BPh), bacteriochlorophyll (BCh), menaquinone, ubiquinone, heme, carotenoid, and Fe. In this study, we utilized mass spectrometry-based proteomics to study this protein complex via bottom-up sequencing, intact protein mass analysis, and native MS ligand-binding analysis. Its primary structure shows a series of mutations, including an unusual alteration and extension on the C-terminus of the M-subunit. In terms of quaternary structure, proteins such as this containing many cofactors serve to test the ability to introduce native-state protein assemblies into the gas phase because the cofactors will not be retained if the quaternary structure is seriously perturbed. Furthermore, this specific RC, under native MS, exhibits a strong ability not only to bind the special pair but also to preserve the two peripheral BCh's.
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Affiliation(s)
- Yue Lu
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
- Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Carrie Goodson
- Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, Missouri 63130, USA
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Robert E. Blankenship
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
- Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, Missouri 63130, USA
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
- Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, Missouri 63130, USA
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Amporndanai K, Johnson RM, O’Neill PM, Fishwick CWG, Jamson AH, Rawson S, Muench SP, Hasnain SS, Antonyuk SV. X-ray and cryo-EM structures of inhibitor-bound cytochrome bc1 complexes for structure-based drug discovery. IUCRJ 2018; 5:200-210. [PMID: 29765610 PMCID: PMC5947725 DOI: 10.1107/s2052252518001616] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/26/2018] [Indexed: 05/10/2023]
Abstract
Cytochrome bc1, a dimeric multi-subunit electron-transport protein embedded in the inner mitochondrial membrane, is a major drug target for the treatment and prevention of malaria and toxoplasmosis. Structural studies of cytochrome bc1 from mammalian homologues co-crystallized with lead compounds have underpinned structure-based drug design to develop compounds with higher potency and selectivity. However, owing to the limited amount of cytochrome bc1 that may be available from parasites, all efforts have been focused on homologous cytochrome bc1 complexes from mammalian species, which has resulted in the failure of some drug candidates owing to toxicity in the host. Crystallographic studies of the native parasite proteins are not feasible owing to limited availability of the proteins. Here, it is demonstrated that cytochrome bc1 is highly amenable to single-particle cryo-EM (which uses significantly less protein) by solving the apo and two inhibitor-bound structures to ∼4.1 Å resolution, revealing clear inhibitor density at the binding site. Therefore, cryo-EM is proposed as a viable alternative method for structure-based drug discovery using both host and parasite enzymes.
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Affiliation(s)
- Kangsa Amporndanai
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, England
| | - Rachel M. Johnson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, England
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
- School of Chemistry, University of Leeds, Leeds LS2 9JT, England
| | - Paul M. O’Neill
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, England
| | - Colin W. G. Fishwick
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
- School of Chemistry, University of Leeds, Leeds LS2 9JT, England
| | - Alexander H. Jamson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, England
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - Shaun Rawson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, England
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - Stephen P. Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, England
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - S. Samar Hasnain
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, England
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, England
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Parmar M, Rawson S, Scarff CA, Goldman A, Dafforn TR, Muench SP, Postis VLG. Using a SMALP platform to determine a sub-nm single particle cryo-EM membrane protein structure. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2018; 1860:378-383. [PMID: 28993151 PMCID: PMC5780298 DOI: 10.1016/j.bbamem.2017.10.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 10/02/2017] [Accepted: 10/04/2017] [Indexed: 01/10/2023]
Abstract
The field of membrane protein structural biology has been revolutionized over the last few years with a number of high profile structures being solved using cryo-EM including Piezo, Ryanodine receptor, TRPV1 and the Glutamate receptor. Further developments in the EM field hold the promise of even greater progress in terms of greater resolution, which for membrane proteins is still typically within the 4-7Å range. One advantage of a cryo-EM approach is the ability to study membrane proteins in more "native" like environments for example proteoliposomes, amphipols and nanodiscs. Recently, styrene maleic acid co-polymers (SMA) have been used to extract membrane proteins surrounded by native lipids (SMALPs) maintaining a more natural environment. We report here the structure of the Escherichia coli multidrug efflux transporter AcrB in a SMALP scaffold to sub-nm resolution, with the resulting map being consistent with high resolution crystal structures and other EM derived maps. However, both the C-terminal helix (TM12) and TM7 are poorly defined in the map. These helices are at the exterior of the helical bundle and form the greater interaction with the native lipids and SMA polymer and may represent a more dynamic region of the protein. This work shows the promise of using an SMA approach for single particle cryo-EM studies to provide sub-nm structures.
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Affiliation(s)
- Mayuriben Parmar
- Biomedicine Research Group, Faculty of Health and Social Sciences, Leeds Beckett University, LS1 3HE, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK
| | - Shaun Rawson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, UK
| | - Charlotte A Scarff
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, UK
| | - Adrian Goldman
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, UK; Department of Biosciences, Division of Biochemistry, University of Helsinki, Helsinki, Finland
| | - Timothy R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Stephen P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, UK.
| | - Vincent L G Postis
- Biomedicine Research Group, Faculty of Health and Social Sciences, Leeds Beckett University, LS1 3HE, UK; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK.
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Koutsioubas A. Low-Resolution Structure of Detergent-Solubilized Membrane Proteins from Small-Angle Scattering Data. Biophys J 2018; 113:2373-2382. [PMID: 29211991 DOI: 10.1016/j.bpj.2017.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/20/2017] [Accepted: 10/03/2017] [Indexed: 11/16/2022] Open
Abstract
Despite the ever-increasing usage of small-angle scattering as a valuable complementary method in the field of structural biology, applications concerning membrane proteins remain elusive mainly due to experimental challenges and the relative lack of theoretical tools for the treatment of scattering data. This fact adds up to general difficulties encountered also by other established methods (crystallography, NMR) for the study of membrane proteins. Following the general paradigm of ab initio methods for low-resolution restoration of soluble protein structure from small-angle scattering data, we construct a general multiphase model with a set of physical constraints, which, together with an appropriate minimization procedure, gives direct structural information concerning the different components (protein, detergent molecules) of detergent-solubilized membrane protein complexes. Assessment of the method's precision and robustness is evaluated by performing shape restorations from simulated data of a tetrameric α-helical membrane channel (Aquaporin-0) solubilized by n-Dodecyl β-D-Maltoside and from previously published small-angle neutron scattering experimental data of the filamentous hemagglutinin adhesin β-barrel protein transporter solubilized by n-Octyl β-D-glucopyranoside. It is shown that the acquisition of small-angle neutron scattering data at two different solvent contrasts, together with an estimation of detergent aggregation number around the protein, permits the reliable reconstruction of the shape of membrane proteins without the need for any prior structural information.
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Affiliation(s)
- Alexandros Koutsioubas
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich, Garching, Germany.
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Muench SP. Everyone needs good neighbours - the intricate relationship between the acetylcholine-receptor channel and its membrane environment. IUCRJ 2017; 4:306-307. [PMID: 28875018 PMCID: PMC5571794 DOI: 10.1107/s2052252517009058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A short commentary is given on the article in this issue by Nigel Unwin [IUCrJ (2017), 4, 393-399] on 'Segregation of lipids near acetylcholine-receptor channels imaged by cryo-EM'.
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Affiliation(s)
- Stephen P. Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, LS2 9JT UK
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Saidijam M, Karimi Dermani F, Sohrabi S, Patching SG. Efflux proteins at the blood-brain barrier: review and bioinformatics analysis. Xenobiotica 2017; 48:506-532. [PMID: 28481715 DOI: 10.1080/00498254.2017.1328148] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
1. Efflux proteins at the blood-brain barrier provide a mechanism for export of waste products of normal metabolism from the brain and help to maintain brain homeostasis. They also prevent entry into the brain of a wide range of potentially harmful compounds such as drugs and xenobiotics. 2. Conversely, efflux proteins also hinder delivery of therapeutic drugs to the brain and central nervous system used to treat brain tumours and neurological disorders. For bypassing efflux proteins, a comprehensive understanding of their structures, functions and molecular mechanisms is necessary, along with new strategies and technologies for delivery of drugs across the blood-brain barrier. 3. We review efflux proteins at the blood-brain barrier, classified as either ATP-binding cassette (ABC) transporters (P-gp, BCRP, MRPs) or solute carrier (SLC) transporters (OATP1A2, OATP1A4, OATP1C1, OATP2B1, OAT3, EAATs, PMAT/hENT4 and MATE1). 4. This includes information about substrate and inhibitor specificity, structural organisation and mechanism, membrane localisation, regulation of expression and activity, effects of diseases and conditions and the principal technique used for in vivo analysis of efflux protein activity: positron emission tomography (PET). 5. We also performed analyses of evolutionary relationships, membrane topologies and amino acid compositions of the proteins, and linked these to structure and function.
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Affiliation(s)
- Massoud Saidijam
- a Department of Molecular Medicine and Genetics , Research Centre for Molecular Medicine, School of Medicine, Hamadan University of Medical Sciences , Hamadan , Iran and
| | - Fatemeh Karimi Dermani
- a Department of Molecular Medicine and Genetics , Research Centre for Molecular Medicine, School of Medicine, Hamadan University of Medical Sciences , Hamadan , Iran and
| | - Sareh Sohrabi
- a Department of Molecular Medicine and Genetics , Research Centre for Molecular Medicine, School of Medicine, Hamadan University of Medical Sciences , Hamadan , Iran and
| | - Simon G Patching
- b School of BioMedical Sciences and the Astbury Centre for Structural Molecular Biology, University of Leeds , Leeds , UK
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