1
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Islam T, Chesnokov ON, Oleinikov AV, Yi P. Supported Erythrocyte Membranes on Piezoelectric Sensors for Studying the Interactions with Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17770-17781. [PMID: 38039387 DOI: 10.1021/acs.langmuir.3c02396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2023]
Abstract
Applications of nanoparticles (NPs) in nanodrugs, food additives, and cosmetics can result in the presence of nanomaterials in the human circulatory system and their attachment to red blood cells (RBCs), which may lead to cytotoxic effects. To investigate the interactions of NPs with RBC membranes (RBCm), supported erythrocyte membranes (SRBCm) were developed on piezoelectric sensors in a quartz crystal microbalance with dissipation (QCM-D) at 25 °C. A well-dispersed RBCm suspension at 1 mM NaCl and 0.2 mM NaHCO3 was obtained from whole blood and comprised colloidal membrane fragments with the average hydrodynamic diameter and zeta potential of 390 nm and -0.53 mV, respectively, at pH 7.0. The thin and rigid SRBCm was formed mainly through the deposition of RBCm fragments on the poly-l-lysine-modified crystal sensor, leading to the average frequency shift of -26.2 Hz and the low ratio of the dissipation to frequency shift (7.2 × 10-8 Hz-1). The complete coverage of SRBCm was indicated by the plateau of the frequency shift in the stage of SRBCm formation and no deposition of negatively charged 106 nm polystyrene nanoparticles (PSNPs) on the SRBCm. Atomic force microscopy and immunofluorescence microscopy images showed that RBCm aggregates with the average size of 420 nm and erythrocyte membrane proteins existed on SRBCm, respectively. The methods of determining attachment efficiencies of model positively charged NPs (i.e., hematite NPs or HemNPs) and model negatively charged NPs (i.e., PSNPs) on SRBCm were demonstrated in 1 mM NaCl solution at pH 5.1 and pH 7.0, respectively. HemNPs exhibited a favorable deposition with an attachment efficiency of 0.99 while PSNPs did not show any attachment propensity toward SRBCm.
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Affiliation(s)
- Tanaz Islam
- Department of Civil, Environmental, and Geomatics Engineering, College of Engineering & Computer Science, Florida Atlantic University, Boca Raton, Florida 33431-6496, United States
| | - Olga N Chesnokov
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431-6496, United States
| | - Andrew V Oleinikov
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431-6496, United States
| | - Peng Yi
- Department of Civil, Environmental, and Geomatics Engineering, College of Engineering & Computer Science, Florida Atlantic University, Boca Raton, Florida 33431-6496, United States
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2
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Milogrodzka I, Nguyen Pham DT, Sama GR, Samadian H, Zhai J, de Campo L, Kirby NM, Scott TF, Banaszak Holl MM, van 't Hag L. Effect of Cholesterol on Biomimetic Membrane Curvature and Coronavirus Fusion Peptide Encapsulation. ACS NANO 2023; 17:8598-8612. [PMID: 37078604 DOI: 10.1021/acsnano.3c01095] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Biomimetic cubic phases can be used for protein encapsulation in a variety of applications such as biosensors and drug delivery. Cubic phases with a high concentration of cholesterol and phospholipids were obtained herein. It is shown that the cubic phase structure can be maintained with a higher concentration of biomimetic membrane additives than has been reported previously. Opposing effects on the curvature of the membrane were observed upon the addition of phospholipids and cholesterol. Furthermore, the coronavirus fusion peptide significantly increased the negative curvature of the biomimetic membrane with cholesterol. We show that the viral fusion peptide can undergo structural changes leading to the formation of hydrophobic α-helices that insert into the lipid bilayer. This is of high importance, as a fusion peptide that induces increased negative curvature as shown by the formation of inverse hexagonal phases allows for greater contact area between two membranes, which is required for viral fusion to occur. The cytotoxicity assay showed that the toxicity toward HeLa cells was dramatically decreased when the cholesterol or peptide level in the nanoparticles increased. This suggests that the addition of cholesterol can improve the biocompatibility of the cubic phase nanoparticles, making them safer for use in biomedical applications. As the results, this work improves the potential for the biomedical end-use applications of the nonlamellar lipid nanoparticles and shows the need of systematic formulation studies due to the complex interplay of all components.
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Affiliation(s)
- Izabela Milogrodzka
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Duy Tue Nguyen Pham
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Gopal R Sama
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Hajar Samadian
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Jiali Zhai
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Liliana de Campo
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Kirrawee, NSW 2234, Australia
| | - Nigel M Kirby
- Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | - Timothy F Scott
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Mark M Banaszak Holl
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
- Department of Mechanical and Materials Engineering, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Leonie van 't Hag
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
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3
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Mardešić I, Boban Z, Subczynski WK, Raguz M. Membrane Models and Experiments Suitable for Studies of the Cholesterol Bilayer Domains. MEMBRANES 2023; 13:320. [PMID: 36984707 PMCID: PMC10057498 DOI: 10.3390/membranes13030320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Cholesterol (Chol) is an essential component of animal cell membranes and is most abundant in plasma membranes (PMs) where its concentration typically ranges from 10 to 30 mol%. However, in red blood cells and Schwann cells, PMs Chol content is as high as 50 mol%, and in the PMs of the eye lens fiber cells, it can reach up to 66 mol%. Being amphiphilic, Chol molecules are easily incorporated into the lipid bilayer where they affect the membrane lateral organization and transmembrane physical properties. In the aqueous phase, Chol cannot form free bilayers by itself. However, pure Chol bilayer domains (CBDs) can form in lipid bilayer membranes with the Chol content exceeding 50 mol%. The range of Chol concentrations surpassing 50 mol% is less frequent in biological membranes and is consequently less investigated. Nevertheless, it is significant for the normal functioning of the eye lens and understanding how Chol plaques form in atherosclerosis. The most commonly used membrane models are unilamellar and multilamellar vesicles (MLVs) and supported lipid bilayers (SLBs). CBDs have been observed directly using confocal microscopy, X-ray reflectometry and saturation recovery electron paramagnetic resonance (SR EPR). Indirect evidence of CBDs has also been reported by using atomic force microscopy (AFM) and fluorescence recovery after photobleaching (FRAP) experiments. The overall goal of this review is to demonstrate the advantages and limitations of the various membrane models and experimental techniques suitable for the detection and investigation of the lateral organization, function and physical properties of CBDs.
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Affiliation(s)
- Ivan Mardešić
- Department of Medical Physics and Biophysics, University of Split School of Medicine, 21000 Split, Croatia; (I.M.); (Z.B.)
- Faculty of Science, University of Split, Doctoral Study of Biophysics, 21000 Split, Croatia
| | - Zvonimir Boban
- Department of Medical Physics and Biophysics, University of Split School of Medicine, 21000 Split, Croatia; (I.M.); (Z.B.)
- Faculty of Science, University of Split, Doctoral Study of Biophysics, 21000 Split, Croatia
| | | | - Marija Raguz
- Department of Medical Physics and Biophysics, University of Split School of Medicine, 21000 Split, Croatia; (I.M.); (Z.B.)
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4
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Braithwaite IM, Davis JH. Orientation of Cholesterol in Polyunsaturated Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15804-15816. [PMID: 36480923 DOI: 10.1021/acs.langmuir.2c02718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The local normal to the fluid liquid crystalline phase of the lipid membrane is an axis of motional symmetry for the molecules that make up the bilayer. The presence of cholesterol in the membrane increases not only the lipid hydrocarbon chain order but also the strength of the membrane's orienting potential. Cholesterol undergoes rapid reorientation about a diffusion axis that is roughly aligned with the long molecular axis, but there is also a slower reorientation of the diffusion axis, or "wobble", relative to the local bilayer normal. The extent of this second, slower motion depends on the degree of order of the lipids that make up the bilayer. We use 2H nuclear magnetic resonance of deuterium-labeled cholesterol to investigate quantitatively the effect of lipid chain unsaturation on cholesterol orientation in a series of phospholipid bilayers. We find that the hydrocarbon chains in membranes composed of polyunsaturated lipids are much more highly disordered than those in membranes composed of saturated lipids but that cholesterol remains aligned roughly along the bilayer normal.
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Affiliation(s)
| | - James H Davis
- Department of Physics, University of Guelph, Guelph, ON, CanadaN1G 2W1
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5
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Ramos-Martín F, D'Amelio N. Biomembrane lipids: When physics and chemistry join to shape biological activity. Biochimie 2022; 203:118-138. [PMID: 35926681 DOI: 10.1016/j.biochi.2022.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/13/2022] [Accepted: 07/21/2022] [Indexed: 11/02/2022]
Abstract
Biomembranes constitute the first lines of defense of cells. While small molecules can often permeate cell walls in bacteria and plants, they are generally unable to penetrate the barrier constituted by the double layer of phospholipids, unless specific receptors or channels are present. Antimicrobial or cell-penetrating peptides are in fact highly specialized molecules able to bypass this barrier and even discriminate among different cell types. This capacity is made possible by the intrinsic properties of its phospholipids, their distribution between the internal and external leaflet, and their ability to mutually interact, modulating the membrane fluidity and the exposition of key headgroups. Although common phospholipids can be found in the membranes of most organisms, some are characteristic of specific cell types. Here, we review the properties of the most common lipids and describe how they interact with each other in biomembrane. We then discuss how their assembly in bilayers determines some key physical-chemical properties such as permeability, potential and phase status. Finally, we describe how the exposition of specific phospholipids determines the recognition of cell types by membrane-targeting molecules.
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Affiliation(s)
- Francisco Ramos-Martín
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, Amiens, 80039, France.
| | - Nicola D'Amelio
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, Amiens, 80039, France.
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6
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Duff AP, Cagnes M, Darwish TA, Krause-Heuer AM, Moir M, Recsei C, Rekas A, Russell RA, Wilde KL, Yepuri NR. Deuteration for biological SANS: Case studies, success and challenges in chemistry and biology. Methods Enzymol 2022; 677:85-126. [DOI: 10.1016/bs.mie.2022.08.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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7
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Ramos J, Laux V, Haertlein M, Forsyth VT, Mossou E, Larsen S, Langkilde AE. The impact of folding modes and deuteration on the atomic resolution structure of hen egg-white lysozyme. Acta Crystallogr D Struct Biol 2021; 77:1579-1590. [PMID: 34866613 PMCID: PMC8647175 DOI: 10.1107/s2059798321010950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/20/2021] [Indexed: 11/10/2022] Open
Abstract
The biological function of a protein is intimately related to its structure and dynamics, which in turn are determined by the way in which it has been folded. In vitro refolding is commonly used for the recovery of recombinant proteins that are expressed in the form of inclusion bodies and is of central interest in terms of the folding pathways that occur in vivo. Here, biophysical data are reported for in vitro-refolded hydrogenated hen egg-white lysozyme, in combination with atomic resolution X-ray diffraction analyses, which allowed detailed comparisons with native hydrogenated and refolded perdeuterated lysozyme. Distinct folding modes are observed for the hydrogenated and perdeuterated refolded variants, which are determined by conformational changes to the backbone structure of the Lys97-Gly104 flexible loop. Surprisingly, the structure of the refolded perdeuterated protein is closer to that of native lysozyme than that of the refolded hydrogenated protein. These structural differences suggest that the observed decreases in thermal stability and enzymatic activity in the refolded perdeuterated and hydrogenated proteins are consequences of the macromolecular deuteration effect and of distinct folding dynamics, respectively. These results are discussed in the context of both in vitro and in vivo folding, as well as of lysozyme amyloidogenesis.
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Affiliation(s)
- Joao Ramos
- Life Sciences Group, Institute Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Valerie Laux
- Life Sciences Group, Institute Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Michael Haertlein
- Life Sciences Group, Institute Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - V. Trevor Forsyth
- Life Sciences Group, Institute Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
- Faculty of Natural Sciences, Keele University, Newcastle ST5 5BG, United Kingdom
- Faculty of Medicine, Lund University, 221 00 Lund, Sweden
- LINXS Institute for Advanced Neutron and X-ray Science, Scheelvagen 19, 223 70 Lund, Sweden
| | - Estelle Mossou
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Sine Larsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Annette E. Langkilde
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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8
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Andrews JT, Baker KE, Handloser JT, Bridges N, Krone AA, Kett PJN. Formation of Supported Lipid Bilayers (SLBs) from Buffers Containing Low Concentrations of Group I Chloride Salts. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:12819-12833. [PMID: 34699227 DOI: 10.1021/acs.langmuir.1c01707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Supported lipid bilayers (SLBs) are a useful tool for studying the interactions between lipids and other biomolecules that make up a cell membrane. SLBs are typically formed by the adsorption and rupture of vesicles from solution. Although it is known that many experimental factors can affect whether SLB formation is successful, there is no comprehensive understanding of the mechanism. In this work, we have used a quartz crystal microbalance (QCM) to investigate the role of the salt in the buffer on the formation of phosphatidylcholine SLBs on a silicon dioxide (SiO2) surface. We varied the concentration of sodium chloride in the buffer, from 5 to 150 mM, to find the minimum concentration of NaCl that was required for the successful formation of an SLB. We then repeated the experiments with other group I chloride salts (LiCl, KCl, and CsCl) and found that at higher salt concentrations (150 mM) SLB formation was successful for all of the salts used, and the degree of deformation of the adsorbed vesicles at the critical vesicle coverage was cation-dependent. The results showed that at an intermediate salt concentration (50 mM) the critical vesicle coverage was cation-dependent and at low salt concentrations (12.5 mM) the cation used determined whether SLB formation was successful. We found that the successful formation of SLBs could occur at lower electrolyte concentrations for KCl and CsCl than it did for NaCl. To understand these results, we calculated the magnitude of the vesicle-surface interaction energy using the Derjaguin-Landau-Verwey-Overbeek (DLVO) and extended-DLVO theory. We managed to explain the results obtained at higher salt concentrations by including cation-dependent surface potentials in the calculations and at lower salt concentrations by the addition of a cation-dependent hydration force. These results showed that the way that different cations in solution affect the 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)-SiO2 surface interaction energy depends on the ionic strength of the solution.
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Affiliation(s)
- J Tucker Andrews
- Department of Chemistry, Hendrix College, 1600 Washington Avenue, Conway, Arkansas 72032, United States
| | - Kirstyn E Baker
- Department of Chemistry, Hendrix College, 1600 Washington Avenue, Conway, Arkansas 72032, United States
| | - Jacob T Handloser
- Department of Chemistry, Hendrix College, 1600 Washington Avenue, Conway, Arkansas 72032, United States
| | - Natalie Bridges
- Department of Chemistry, Hendrix College, 1600 Washington Avenue, Conway, Arkansas 72032, United States
| | - Alexis A Krone
- Department of Chemistry, Hendrix College, 1600 Washington Avenue, Conway, Arkansas 72032, United States
| | - Peter J N Kett
- Department of Chemistry, Hendrix College, 1600 Washington Avenue, Conway, Arkansas 72032, United States
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9
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Eves BJ, Doutch JJ, Terry AE, Yin H, Moulin M, Haertlein M, Forsyth VT, Flagmeier P, Knowles TPJ, Dias DM, Lotze G, Seddon AM, Squires AM. Elongation rate and average length of amyloid fibrils in solution using isotope-labelled small-angle neutron scattering. RSC Chem Biol 2021; 2:1232-1238. [PMID: 34458836 PMCID: PMC8341957 DOI: 10.1039/d1cb00001b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/06/2021] [Indexed: 12/22/2022] Open
Abstract
We demonstrate a solution method that allows both elongation rate and average fibril length of assembling amyloid fibrils to be estimated. The approach involves acquisition of real-time neutron scattering data during the initial stages of seeded growth, using contrast matched buffer to make the seeds effectively invisible to neutrons. As deuterated monomers add on to the seeds, the labelled growing ends give rise to scattering patterns that we model as cylinders whose increase in length with time gives an elongation rate. In addition, the absolute intensity of the signal can be used to determine the number of growing ends per unit volume, which in turn provides an estimate of seed length. The number of ends did not change significantly during elongation, demonstrating that any spontaneous or secondary nucleation was not significant compared with growth on the ends of pre-existing fibrils, and in addition providing a method of internal validation for the technique. Our experiments on initial growth of alpha synuclein fibrils using 1.2 mg ml-1 seeds in 2.5 mg ml-1 deuterated monomer at room temperature gave an elongation rate of 6.3 ± 0.5 Å min-1, and an average seed length estimate of 4.2 ± 1.3 μm.
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Affiliation(s)
- Ben J Eves
- Department of Chemistry, University of Bath Bath UK
| | - James J Doutch
- ISIS Facility, Rutherford Appleton Laboratory, STFC, Chilton Didcot OX11 0QX UK
| | - Ann E Terry
- MAX IV Laboratory, Lund University P.O. Box 118 Lund 221 00 Sweden
| | - Han Yin
- Department of Chemistry, University of Bath Bath UK
| | - Martine Moulin
- Life Sciences Group, Institut Laue Langevin 38042 Grenoble Cedex 9 France
| | - Michael Haertlein
- Life Sciences Group, Institut Laue Langevin 38042 Grenoble Cedex 9 France
| | - V Trevor Forsyth
- Life Sciences Group, Institut Laue Langevin 38042 Grenoble Cedex 9 France
- School of Chemistry & Physics Keele University Staffordshire ST5 5BG UK
| | - Patrick Flagmeier
- Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK
- Centre for Misfolding Diseases, University of Cambridge Cambridge CB2 1EW UK
| | - Tuomas P J Knowles
- Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK
- Centre for Misfolding Diseases, University of Cambridge Cambridge CB2 1EW UK
| | - David M Dias
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford South Parks Road Oxford OX1 3QZ UK
| | - Gudrun Lotze
- MAX IV Laboratory, Lund University P.O. Box 118 Lund 221 00 Sweden
| | - Annela M Seddon
- School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, University of Bristol Bristol BS8 1TL UK
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10
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Correa Y, Waldie S, Thépaut M, Micciulla S, Moulin M, Fieschi F, Pichler H, Trevor Forsyth V, Haertlein M, Cárdenas M. SARS-CoV-2 spike protein removes lipids from model membranes and interferes with the capacity of high density lipoprotein to exchange lipids. J Colloid Interface Sci 2021; 602:732-739. [PMID: 34157514 PMCID: PMC8195693 DOI: 10.1016/j.jcis.2021.06.056] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 01/18/2023]
Abstract
Cholesterol has been shown to affect the extent of coronavirus binding and fusion to cellular membranes. The severity of Covid-19 infection is also known to be correlated with lipid disorders. Furthermore, the levels of both serum cholesterol and high-density lipoprotein (HDL) decrease with Covid-19 severity, with normal levels resuming once the infection has passed. Here we demonstrate that the SARS-CoV-2 spike (S) protein interferes with the function of lipoproteins, and that this is dependent on cholesterol. In particular, the ability of HDL to exchange lipids from model cellular membranes is altered when co-incubated with the spike protein. Additionally, the S protein removes lipids and cholesterol from model membranes. We propose that the S protein affects HDL function by removing lipids from it and remodelling its composition/structure.
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Affiliation(s)
- Yubexi Correa
- Biofilms - Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden
| | - Sarah Waldie
- Biofilms - Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden; Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France
| | - Michel Thépaut
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France
| | - Samantha Micciulla
- Large Scale Structures, Institut Laue Langevin (ILL), Grenoble F-38042, France
| | - Martine Moulin
- Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France
| | - Franck Fieschi
- Partnership for Structural Biology, Grenoble F-38042, France; Univ. Grenoble Alpes, CNRS, CEA, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France
| | - Harald Pichler
- Austrian Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria; Graz University of Technology, Institute of Molecular Biotechnology, NAWI Graz, BioTechMed Graz, Petersgasse 14, 8010 Graz, Austria
| | - V Trevor Forsyth
- Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France; Faculty of Natural Sciences, Keele University, Staffordshire ST5 5BG, UK.
| | - Michael Haertlein
- Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France.
| | - Marité Cárdenas
- Biofilms - Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden.
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11
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Why Do Tethered-Bilayer Lipid Membranes Suit for Functional Membrane Protein Reincorporation? APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11114876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Membrane proteins (MPs) are essential for cellular functions. Understanding the functions of MPs is crucial as they constitute an important class of drug targets. However, MPs are a challenging class of biomolecules to analyze because they cannot be studied outside their native environment. Their structure, function and activity are highly dependent on the local lipid environment, and these properties are compromised when the protein does not reside in the cell membrane. Mammalian cell membranes are complex and composed of different lipid species. Model membranes have been developed to provide an adequate environment to envisage MP reconstitution. Among them, tethered-Bilayer Lipid Membranes (tBLMs) appear as the best model because they allow the lipid bilayer to be decoupled from the support. Thus, they provide a sufficient aqueous space to envisage the proper accommodation of large extra-membranous domains of MPs, extending outside. Additionally, as the bilayer remains attached to tethers covalently fixed to the solid support, they can be investigated by a wide variety of surface-sensitive analytical techniques. This review provides an overview of the different approaches developed over the last two decades to achieve sophisticated tBLMs, with a more and more complex lipid composition and adapted for functional MP reconstitution.
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12
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Ramos J, Laux V, Haertlein M, Boeri Erba E, McAuley KE, Forsyth VT, Mossou E, Larsen S, Langkilde AE. Structural insights into protein folding, stability and activity using in vivo perdeuteration of hen egg-white lysozyme. IUCRJ 2021; 8:372-386. [PMID: 33953924 PMCID: PMC8086161 DOI: 10.1107/s2052252521001299] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
This structural and biophysical study exploited a method of perdeuterating hen egg-white lysozyme based on the expression of insoluble protein in Escherichia coli followed by in-column chemical refolding. This allowed detailed comparisons with perdeuterated lysozyme produced in the yeast Pichia pastoris, as well as with unlabelled lysozyme. Both perdeuterated variants exhibit reduced thermal stability and enzymatic activity in comparison with hydrogenated lysozyme. The thermal stability of refolded perdeuterated lysozyme is 4.9°C lower than that of the perdeuterated variant expressed and secreted in yeast and 6.8°C lower than that of the hydrogenated Gallus gallus protein. However, both perdeuterated variants exhibit a comparable activity. Atomic resolution X-ray crystallographic analyses show that the differences in thermal stability and enzymatic function are correlated with refolding and deuteration effects. The hydrogen/deuterium isotope effect causes a decrease in the stability and activity of the perdeuterated analogues; this is believed to occur through a combination of changes to hydrophobicity and protein dynamics. The lower level of thermal stability of the refolded perdeuterated lysozyme is caused by the unrestrained Asn103 peptide-plane flip during the unfolded state, leading to a significant increase in disorder of the Lys97-Gly104 region following subsequent refolding. An ancillary outcome of this study has been the development of an efficient and financially viable protocol that allows stable and active perdeuterated lysozyme to be more easily available for scientific applications.
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Affiliation(s)
- Joao Ramos
- Life Sciences Group, Institut Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Valerie Laux
- Life Sciences Group, Institut Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Michael Haertlein
- Life Sciences Group, Institut Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Elisabetta Boeri Erba
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
- Institut de Biologie Structurale, Université de Grenoble Alpes, CEA, CNRS, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Katherine E. McAuley
- Diamond Light Source, Didcot OX11 0DE, United Kingdom
- Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen, Switzerland
| | - V. Trevor Forsyth
- Life Sciences Group, Institut Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
- Faculty of Natural Sciences, Keele University, Newcastle-under-Lyme ST5 5BG, United Kingdom
| | - Estelle Mossou
- Life Sciences Group, Institut Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
- Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, 38000 Grenoble, France
- Faculty of Natural Sciences, Keele University, Newcastle-under-Lyme ST5 5BG, United Kingdom
| | - Sine Larsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Annette E. Langkilde
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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13
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Waldie S, Sebastiani F, Moulin M, Del Giudice R, Paracini N, Roosen-Runge F, Gerelli Y, Prevost S, Voss JC, Darwish TA, Yepuri N, Pichler H, Maric S, Forsyth VT, Haertlein M, Cárdenas M. ApoE and ApoE Nascent-Like HDL Particles at Model Cellular Membranes: Effect of Protein Isoform and Membrane Composition. Front Chem 2021; 9:630152. [PMID: 33996741 PMCID: PMC8117676 DOI: 10.3389/fchem.2021.630152] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/30/2021] [Indexed: 11/13/2022] Open
Abstract
Apolipoprotein E (ApoE), an important mediator of lipid transportation in plasma and the nervous system, plays a large role in diseases such as atherosclerosis and Alzheimer's. The major allele variants ApoE3 and ApoE4 differ only by one amino acid. However, this difference has major consequences for the physiological behaviour of each variant. In this paper, we follow (i) the initial interaction of lipid-free ApoE variants with model membranes as a function of lipid saturation, (ii) the formation of reconstituted High-Density Lipoprotein-like particles (rHDL) and their structural characterisation, and (iii) the rHDL ability to exchange lipids with model membranes made of saturated lipids in the presence and absence of cholesterol [1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) or 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) with and without 20 mol% cholesterol]. Our neutron reflection results demonstrate that the protein variants interact differently with the model membranes, adopting different protein conformations. Moreover, the ApoE3 structure at the model membrane is sensitive to the level of lipid unsaturation. Small-angle neutron scattering shows that the ApoE containing lipid particles form elliptical disc-like structures, similar in shape but larger than nascent or discoidal HDL based on Apolipoprotein A1 (ApoA1). Neutron reflection shows that ApoE-rHDL do not remove cholesterol but rather exchange saturated lipids, as occurs in the brain. In contrast, ApoA1-containing particles remove and exchange lipids to a greater extent as occurs elsewhere in the body.
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Affiliation(s)
- Sarah Waldie
- Department of Biomedical Science and Biofilms-Research Center for Biointerfaces, Malmö University, Malmö, Sweden.,Institut Laue-Langevin, Grenoble, France.,Partnership for Structural Biology (PSB), Grenoble, France
| | - Federica Sebastiani
- Department of Biomedical Science and Biofilms-Research Center for Biointerfaces, Malmö University, Malmö, Sweden
| | - Martine Moulin
- Institut Laue-Langevin, Grenoble, France.,Partnership for Structural Biology (PSB), Grenoble, France
| | - Rita Del Giudice
- Department of Biomedical Science and Biofilms-Research Center for Biointerfaces, Malmö University, Malmö, Sweden
| | - Nicolò Paracini
- Department of Biomedical Science and Biofilms-Research Center for Biointerfaces, Malmö University, Malmö, Sweden
| | - Felix Roosen-Runge
- Department of Biomedical Science and Biofilms-Research Center for Biointerfaces, Malmö University, Malmö, Sweden
| | - Yuri Gerelli
- Institut Laue-Langevin, Grenoble, France.,Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | | | - John C Voss
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
| | - Tamim A Darwish
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, Australia
| | - Nageshwar Yepuri
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, Australia
| | - Harald Pichler
- Austrian Centre of Industrial Biotechnology, Graz, Austria.,Graz University of Technology, Institute of Molecular Biotechnology, NAWI Graz, BioTechMed Graz, Graz, Austria
| | | | - V Trevor Forsyth
- Institut Laue-Langevin, Grenoble, France.,Partnership for Structural Biology (PSB), Grenoble, France.,Faculty of Natural Sciences, Keele University, Staffordshire, United Kingdom
| | - Michael Haertlein
- Institut Laue-Langevin, Grenoble, France.,Partnership for Structural Biology (PSB), Grenoble, France
| | - Marité Cárdenas
- Department of Biomedical Science and Biofilms-Research Center for Biointerfaces, Malmö University, Malmö, Sweden
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14
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Perissinotto F, Rondelli V, Senigagliesi B, Brocca P, Almásy L, Bottyán L, Merkel DG, Amenitsch H, Sartori B, Pachler K, Mayr M, Gimona M, Rohde E, Casalis L, Parisse P. Structural insights into fusion mechanisms of small extracellular vesicles with model plasma membranes. NANOSCALE 2021; 13:5224-5233. [PMID: 33687046 DOI: 10.1039/d0nr09075a] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Extracellular vesicles (EVs) are a potent intercellular communication system. Such small vesicles transport biomolecules between cells and throughout the body, strongly influencing the fate of recipient cells. Due to their specific biological functions they have been proposed as biomarkers for various diseases and as optimal candidates for therapeutic applications. Despite their extreme biological relevance, their mechanisms of interaction with the membranes of recipient cells are still hotly debated. Here, we propose a multiscale investigation based on atomic force microscopy, small angle X-ray scattering, small angle neutron scattering and neutron reflectometry to reveal structure-function correlations of purified EVs in interaction with model membrane systems of variable complex compositions and to spot the role of different membrane phases on the vesicle internalization routes. Our analysis reveals strong interactions of EVs with the model membranes and preferentially with the borders of protruding phase domains. Moreover, we found that upon vesicle breaking on the model membrane surface, the biomolecules carried by/on EVs diffuse with different kinetics rates, in a process distinct from simple fusion. The biophysical platform proposed here has clear implications on the modulation of EV internalization routes by targeting specific domains at the plasma cell membrane and, as a consequence, on EV-based therapies.
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Affiliation(s)
- Fabio Perissinotto
- Elettra Sincrotrone Trieste, Trieste, Italy. and Center for Infection and Immunity of Lille, INSERM U1019, Institut Pasteur de Lille, Lille, France
| | - Valeria Rondelli
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Italy
| | | | - Paola Brocca
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Italy
| | | | - László Bottyán
- Centre for Energy Research, Budapest, Hungary and Wigner Research Centre for Physics, Budapest, Hungary
| | - Dániel Géza Merkel
- Centre for Energy Research, Budapest, Hungary and Wigner Research Centre for Physics, Budapest, Hungary
| | - Heinz Amenitsch
- Institute of Inorganic Chemistry, Graz University of Technology, Graz, Austria
| | - Barbara Sartori
- Institute of Inorganic Chemistry, Graz University of Technology, Graz, Austria
| | - Karin Pachler
- GMP Unit, Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University (PMU), Salzburg, Austria and Research Program "Nanovesicular Therapies", Paracelsus Medical University, Salzburg, Austria
| | - Magdalena Mayr
- GMP Unit, Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University (PMU), Salzburg, Austria
| | - Mario Gimona
- GMP Unit, Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University (PMU), Salzburg, Austria and Research Program "Nanovesicular Therapies", Paracelsus Medical University, Salzburg, Austria
| | - Eva Rohde
- Research Program "Nanovesicular Therapies", Paracelsus Medical University, Salzburg, Austria and Department of Transfusion Medicine, University Hospital, Salzburger Landeskliniken, Austria
| | | | - Pietro Parisse
- Elettra Sincrotrone Trieste, Trieste, Italy. and CNR-IOM, Trieste, Italy
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15
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Patel P, Santo KP, Burgess S, Vishnyakov A, Neimark AV. Stability of Lipid Coatings on Nanoparticle-Decorated Surfaces. ACS NANO 2020; 14:17273-17284. [PMID: 33226210 DOI: 10.1021/acsnano.0c07298] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Lipid membranes supported on solid surfaces and nanoparticles find multiple applications in industrial and biomedical technologies. Here, we explore in silico the mechanisms of the interactions of lipid membranes with nanostructured surfaces with deposited nanoparticles and explain the characteristic particle size dependence of the uniformity and stability of lipid coatings observed in vitro. Simulations are performed to demonstrate the specifics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid membrane adhesion to hydrophilic and hydrophobic nanoparticles ranging in size from 1.5 to 40 nm using an original coarse-grained molecular dynamics model with implicit solvent and large simulation boxes (scales up to 280 × 154 × 69 nm3). We find that one of the major factors that affects the uniformity and stability of lipid coatings is the disjoining pressure in the water hydration layer formed between the lipid membrane and hydrophilic solid surface. This effect is accounted for by introducing a special long-range lipid-solid interaction potential that mimics the effects of the disjoining pressure in thin water layers. Our simulations reveal the physical mechanisms of interactions of lipid bilayers with solid surfaces that are responsible for the experimentally observed nonmonotonic particle size dependence of the uniformity and stability of lipid coatings: particles smaller than the hydration layer thickness (<2-3 nm) or larger than ∼20 nm are partially or fully enfolded by a lipid bilayer, whereas particles of the intermediate size (5-20 nm) cause membrane perforation and pore formation. In contrast, hydrophobic nanoparticles, which repel the hydration layer, tend to be encapsulated within the hydrophobic interior of the membrane and coated by the lipid monolayer. The proposed model can be further extended and applied to a wide class of systems comprising nanoparticles and nanostructured substrates interacting with lipid and surfactant bilayers and monolayers.
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Affiliation(s)
- Parva Patel
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Kolattukudy P Santo
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Sean Burgess
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Aleksey Vishnyakov
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
- Skolkovo Institute of Technology, Moscow 143005, Russia
| | - Alexander V Neimark
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
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16
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Qian S, Sharma VK, Clifton LA. Understanding the Structure and Dynamics of Complex Biomembrane Interactions by Neutron Scattering Techniques. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15189-15211. [PMID: 33300335 DOI: 10.1021/acs.langmuir.0c02516] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The membrane is one of the key structural materials of biology at the cellular level. Composed predominantly of a bilayer of lipids with embedded and bound proteins, it defines the boundaries of the cell and many organelles essential to life and therefore is involved in almost all biological processes. Membrane-specific interactions, such as drug binding to a membrane receptor or the interactions of an antimicrobial compound with the lipid matrix of a pathogen membrane, are of interest across the scientific disciplines. Herein we present a review, aimed at nonexperts, of the major neutron scattering techniques used in membrane studies: small-angle neutron scattering, neutron membrane diffraction, neutron reflectometry, quasielastic neutron scattering, and neutron spin echo. Neutron scattering techniques are well suited to studying biological membranes. The nondestructive nature of cold neutrons means that samples can be measured for long periods without fear of beam damage from ultraviolet, electron, or X-ray radiation, and neutron beams are highly penetrating, thus offering flexibility in samples and sample environments. Most important is the strong difference in neutron scattering lengths between the two most abundant forms of hydrogen, protium and deuterium. Changing the relative amounts of protium/deuterium in a sample allows the production of a series of neutron scattering data sets, enabling the observation of differing components within complex membrane architectures. This approach can be as simple as using the naturally occurring neutron contrast between different biomolecules to study components in a complex by changing the solution H2O/D2O ratio or as complex as selectively labeling individual components with hydrogen isotopes. This review presents an overview of each experimental technique with the neutron instrument configuration, related sample preparation and sample environment, and data analysis, highlighted by a special emphasis on using prominent neutron contrast to understand structure and dynamics. This review gives researchers a practical introduction to the often enigmatic suite of neutron beamlines, thereby lowering the barrier to taking advantage of these large-facility techniques to achieve new understandings of membranes and their interactions with other molecules.
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Affiliation(s)
- Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Veerendra Kumar Sharma
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Luke A Clifton
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire, U.K. OX11 0QX
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17
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The Antifungal Mechanism of Amphotericin B Elucidated in Ergosterol and Cholesterol-Containing Membranes Using Neutron Reflectometry. NANOMATERIALS 2020; 10:nano10122439. [PMID: 33291326 PMCID: PMC7762259 DOI: 10.3390/nano10122439] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 12/25/2022]
Abstract
We have characterized and compared the structures of ergosterol- and cholesterol-containing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membranes before and after interaction with the amphiphilic antifungal drug amphotericin B (AmB) using neutron reflection. AmB inserts into both pure POPC and sterol-containing membranes in the lipid chain region and does not significantly perturb the structure of pure POPC membranes. By selective per-deuteration of the lipids/sterols, we show that AmB extracts ergosterol but not cholesterol from the bilayers and inserts to a much higher degree in the cholesterol-containing membranes. Ergosterol extraction by AmB is accompanied by membrane thinning. Our results provide new insights into the mechanism and antifungal effect of AmB in these simple models of fungal and mammalian membranes and help understand the molecular origin of its selectivity and toxic side effects.
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18
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McCluskey AR, Cooper JFK, Arnold T, Snow T. A general approach to maximise information density in neutron reflectometry analysis. MACHINE LEARNING: SCIENCE AND TECHNOLOGY 2020. [DOI: 10.1088/2632-2153/ab94c4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Neutron and x-ray reflectometry are powerful techniques facilitating the study of the structure of interfacial materials. The analysis of these techniques is ill-posed in nature requiring the application of model-dependent methods. This can lead to the over- and under- analysis of experimental data when too many or too few parameters are allowed to vary in the model. In this work, we outline a robust and generic framework for the determination of the set of free parameters that are capable of maximising the information density of the model. This framework involves the determination of the Bayesian evidence for each permutation of free parameters; and is applied to a simple phospholipid monolayer. We believe this framework should become an important component in reflectometry data analysis and hope others more regularly consider the relative evidence for their analytical models.
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19
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Liu Y, Zhang D, Zhang Y, Tang Y, Xu L, He H, Wu J, Zheng J. Molecular Dynamics Simulations of Cholesterol Effects on the Interaction of hIAPP with Lipid Bilayer. J Phys Chem B 2020; 124:7830-7841. [DOI: 10.1021/acs.jpcb.0c05742] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Yonglan Liu
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Dong Zhang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Yanxian Zhang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Yijing Tang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Lijian Xu
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices College of Life Science and Chemistry, Hunan University of Technology, Zhuzhou 412007, P. R. China
| | - Huacheng He
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325027, P. R. China
| | - Jiang Wu
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P. R. China
| | - Jie Zheng
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, Ohio 44325, United States
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20
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Lipoprotein ability to exchange and remove lipids from model membranes as a function of fatty acid saturation and presence of cholesterol. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158769. [PMID: 32712249 DOI: 10.1016/j.bbalip.2020.158769] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/11/2020] [Accepted: 07/19/2020] [Indexed: 11/23/2022]
Abstract
Lipoproteins play a central role in the development of atherosclerosis. High and low-density lipoproteins (HDL and LDL), known as 'good' and 'bad' cholesterol, respectively, remove and/or deposit lipids into the artery wall. Hence, insight into lipid exchange processes between lipoproteins and cell membranes is of particular importance in understanding the onset and development of cardiovascular disease. In order to elucidate the impact of phospholipid tail saturation and the presence of cholesterol in cell membranes on these processes, neutron reflection was employed in the present investigation to follow lipid exchange with both HDL and LDL against model membranes. Mirroring clinical risk factors for the development of atherosclerosis, lower exchange was observed in the presence of cholesterol, as well as for an unsaturated phospholipid, compared to faster exchange when using a fully saturated phospholipid. These results highlight the importance of membrane composition on the interaction with lipoproteins, chiefly the saturation level of the lipids and presence of cholesterol, and provide novel insight into factors of importance for build-up and reversibility of atherosclerotic plaque. In addition, the correlation between the results and well-established clinical risk factors suggests that the approach taken can be employed also for understanding a broader set of risk factors including, e.g., effects of triglycerides and oxidative stress, as well as local effects of drugs on atherosclerotic plaque formation.
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21
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Gajdos L, Forsyth VT, Blakeley MP, Haertlein M, Imberty A, Samain E, Devos JM. Production of perdeuterated fucose from glyco-engineered bacteria. Glycobiology 2020; 31:151-158. [PMID: 32601663 PMCID: PMC7874385 DOI: 10.1093/glycob/cwaa059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/29/2020] [Accepted: 06/16/2020] [Indexed: 12/31/2022] Open
Abstract
l-Fucose and l-fucose-containing polysaccharides, glycoproteins or glycolipids play an important role in a variety of biological processes. l-Fucose-containing glycoconjugates have been implicated in many diseases including cancer and rheumatoid arthritis. Interest in fucose and its derivatives is growing in cancer research, glyco-immunology, and the study of host–pathogen interactions. l-Fucose can be extracted from bacterial and algal polysaccharides or produced (bio)synthetically. While deuterated glucose and galactose are available, and are of high interest for metabolic studies and biophysical studies, deuterated fucose is not easily available. Here, we describe the production of perdeuterated l-fucose, using glyco-engineered Escherichia coli in a bioreactor with the use of a deuterium oxide-based growth medium and a deuterated carbon source. The final yield was 0.2 g L−1 of deuterated sugar, which was fully characterized by mass spectrometry and nuclear magnetic resonance spectroscopy. We anticipate that the perdeuterated fucose produced in this way will have numerous applications in structural biology where techniques such as NMR, solution neutron scattering and neutron crystallography are widely used. In the case of neutron macromolecular crystallography, the availability of perdeuterated fucose can be exploited in identifying the details of its interaction with protein receptors and notably the hydrogen bonding network around the carbohydrate binding site.
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Affiliation(s)
- Lukas Gajdos
- Life Sciences Group, Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble 38000, France.,Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, Grenoble 38000, France.,Université Grenoble Alpes, CNRS, CERMAV, Grenoble 38000, France
| | - V Trevor Forsyth
- Life Sciences Group, Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble 38000, France.,Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, Grenoble 38000, France.,Faculty of Natural Sciences, Keele University, Staffordshire ST5 5BG, UK
| | - Matthew P Blakeley
- Large Scale Structures Group, Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble 38000, France
| | - Michael Haertlein
- Life Sciences Group, Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble 38000, France.,Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, Grenoble 38000, France
| | - Anne Imberty
- Université Grenoble Alpes, CNRS, CERMAV, Grenoble 38000, France
| | - Eric Samain
- Université Grenoble Alpes, CNRS, CERMAV, Grenoble 38000, France
| | - Juliette M Devos
- Life Sciences Group, Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble 38000, France.,Partnership for Structural Biology (PSB), 71 Avenue des Martyrs, Grenoble 38000, France
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22
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Clifton LA, Campbell RA, Sebastiani F, Campos-Terán J, Gonzalez-Martinez JF, Björklund S, Sotres J, Cárdenas M. Design and use of model membranes to study biomolecular interactions using complementary surface-sensitive techniques. Adv Colloid Interface Sci 2020; 277:102118. [PMID: 32044469 DOI: 10.1016/j.cis.2020.102118] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/24/2020] [Accepted: 01/29/2020] [Indexed: 01/07/2023]
Abstract
Cellular membranes are complex structures and simplified analogues in the form of model membranes or biomembranes are used as platforms to understand fundamental properties of the membrane itself as well as interactions with various biomolecules such as drugs, peptides and proteins. Model membranes at the air-liquid and solid-liquid interfaces can be studied using a range of complementary surface-sensitive techniques to give a detailed picture of both the structure and physicochemical properties of the membrane and its resulting interactions. In this review, we will present the main planar model membranes used in the field to date with a focus on monolayers at the air-liquid interface, supported lipid bilayers at the solid-liquid interface and advanced membrane models such as tethered and floating membranes. We will then briefly present the principles as well as the main type of information on molecular interactions at model membranes accessible using a Langmuir trough, quartz crystal microbalance with dissipation monitoring, ellipsometry, atomic force microscopy, Brewster angle microscopy, Infrared spectroscopy, and neutron and X-ray reflectometry. A consistent example for following biomolecular interactions at model membranes is used across many of the techniques in terms of the well-studied antimicrobial peptide Melittin. The overall objective is to establish an understanding of the information accessible from each technique, their respective advantages and limitations, and their complementarity.
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Affiliation(s)
- Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 OQX, United Kingdom
| | - Richard A Campbell
- Division of Pharmacy and Optometry, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Federica Sebastiani
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - José Campos-Terán
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Unidad Cuajimalpa, Av. Vasco de Quiroga 4871, Col. Santa Fe, Delegación Cuajimalpa de Morelos, 05348, Mexico; Lund Institute of advanced Neutron and X-ray Science, Lund University, Scheelevägen 19, 223 70 Lund, Sweden
| | - Juan F Gonzalez-Martinez
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Sebastian Björklund
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Javier Sotres
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Marité Cárdenas
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden.
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23
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Jackman JA, Cho NJ. Supported Lipid Bilayer Formation: Beyond Vesicle Fusion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:1387-1400. [PMID: 31990559 DOI: 10.1021/acs.langmuir.9b03706] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Supported lipid bilayers (SLBs) are cell-membrane-mimicking platforms that can be formed on solid surfaces and integrated with a wide range of surface-sensitive measurement techniques. SLBs are useful for unravelling details of fundamental membrane biology and biophysics as well as for various medical, biotechnology, and environmental science applications. Thus, there is high interest in developing simple and robust methods to fabricate SLBs. Currently, vesicle fusion is a popular method to form SLBs and involves the adsorption and spontaneous rupture of lipid vesicles on a solid surface. However, successful vesicle fusion depends on high-quality vesicle preparation, and it typically works with a narrow range of material supports and lipid compositions. In this Feature Article, we summarize current progress in developing two new SLB fabrication techniques termed the solvent-assisted lipid bilayer (SALB) and bicelle methods, which have compelling advantages such as simple sample preparation and compatibility with a wide range of material supports and lipid compositions. The molecular self-assembly principles underpinning the two strategies and important experimental parameters are critically discussed, and recent application examples are presented. Looking forward, we envision that these emerging SLB fabrication strategies can be widely adopted by specialists and nonspecialists alike, paving the way to enriching our understanding of lipid membrane properties and realizing new application possibilities.
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Affiliation(s)
- Joshua A Jackman
- School of Chemical Engineering , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Nam-Joon Cho
- School of Materials Science and Engineering , Nanyang Technological University , 50 Nanyang Avenue , Singapore 639798 , Singapore
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Hoogerheide DP, Forsyth VT, Brown KA. Neutron scattering for STRUCTURAL BIOLOGY: Modern neutron sources illuminate the complex functions of living systems. PHYSICS TODAY 2020; 73:10.1063/pt.3.4498. [PMID: 38487716 PMCID: PMC10938470 DOI: 10.1063/pt.3.4498] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
Modern neutron sources illuminate the complex functions of living systems.
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Affiliation(s)
- David P Hoogerheide
- National Institute of Standards and Technology Center for Neutron Research in Gaithersburg, Maryland
| | - V Trevor Forsyth
- Institut Laue-Langevin in Grenoble, France; he also holds a chair in biophysics at Keele University in the UK
| | - Katherine A Brown
- Cavendish Laboratory at Cambridge University in the UK and at the University of Texas at Austin
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25
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Lakey JH. Recent advances in neutron reflectivity studies of biological membranes. Curr Opin Colloid Interface Sci 2019. [DOI: 10.1016/j.cocis.2019.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Lind TK, Skoda MWA, Cárdenas M. Formation and Characterization of Supported Lipid Bilayers Composed of Phosphatidylethanolamine and Phosphatidylglycerol by Vesicle Fusion, a Simple but Relevant Model for Bacterial Membranes. ACS OMEGA 2019; 4:10687-10694. [PMID: 31460166 PMCID: PMC6648305 DOI: 10.1021/acsomega.9b01075] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/06/2019] [Indexed: 05/06/2023]
Abstract
Supported lipid bilayers (SLBs) are simple and robust biomimics with controlled lipid composition that are widely used as models of both mammalian and bacterial membranes. However, the lipids typically used for SLB formation poorly resemble those of bacterial cell membranes due to the lack of available protocols to form SLBs using mixtures of lipids relevant for bacteria such as phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). Although a few reports have been published recently on the formation of SLBs from Escherichia coli lipid extracts, a detailed understanding of these systems is challenging due to the complexity of the lipid composition in such natural extracts. Here, we present for the first time a simple and reliable protocol optimized to form high-quality SLBs using mixtures of PE and PG at compositions relevant for Gram-negative membranes. We show using neutron reflection and quartz microbalance not only that Ca2+ ions and temperature are key parameters for successful bilayer deposition but also that mass transfer to the surface is a limiting factor. Continuous flow of the lipid suspension is thus crucial for obtaining full SLB coverage. We furthermore characterize the resulting bilayers and report structural parameters, for the first time for PE and PG mixtures, which are in good agreement with those reported earlier for pure POPE vesicles. With this protocol in place, more suitable and reproducible studies can be conducted to understand biomolecular processes occurring at cell membranes, for example, for testing specificities and to unravel the mechanism of interaction of antimicrobial peptides.
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Affiliation(s)
- Tania Kjellerup Lind
- Biofilms Research
Centre for Biointerfaces and Biomedical Science Department, Faculty
of Health and Society, Malmo University, Malmo 20506, Sweden
| | | | - Marité Cárdenas
- Biofilms Research
Centre for Biointerfaces and Biomedical Science Department, Faculty
of Health and Society, Malmo University, Malmo 20506, Sweden
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27
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Maric S, Lind TK, Raida MR, Bengtsson E, Fredrikson GN, Rogers S, Moulin M, Haertlein M, Forsyth VT, Wenk MR, Pomorski TG, Arnebrant T, Lund R, Cárdenas M. Time-resolved small-angle neutron scattering as a probe for the dynamics of lipid exchange between human lipoproteins and naturally derived membranes. Sci Rep 2019; 9:7591. [PMID: 31110185 PMCID: PMC6527577 DOI: 10.1038/s41598-019-43713-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/27/2019] [Indexed: 12/21/2022] Open
Abstract
Atherosclerosis is the main killer in the western world. Today’s clinical markers include the total level of cholesterol and high-/low-density lipoproteins, which often fails to accurately predict the disease. The relationship between the lipid exchange capacity and lipoprotein structure should explain the extent by which they release or accept lipid cargo and should relate to the risk for developing atherosclerosis. Here, small-angle neutron scattering and tailored deuteration have been used to follow the molecular lipid exchange between human lipoprotein particles and cellular membrane mimics made of natural, “neutron invisible” phosphatidylcholines. We show that lipid exchange occurs via two different processes that include lipid transfer via collision and upon direct particle tethering to the membrane, and that high-density lipoprotein excels at exchanging the human-like unsaturated phosphatidylcholine. By mapping the specific lipid content and level of glycation/oxidation, the mode of action of specific lipoproteins can now be deciphered. This information can prove important for the development of improved diagnostic tools and in the treatment of atherosclerosis.
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Affiliation(s)
- Selma Maric
- Dept. of Biomedical Science, Malmö University, Per Albin Hanssons väg 35, 205 02, Malmö, Sweden.
| | - Tania Kjellerup Lind
- Dept. of Biomedical Science, Malmö University, Per Albin Hanssons väg 35, 205 02, Malmö, Sweden
| | - Manfred Roman Raida
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Eva Bengtsson
- Dept. of Clinical Sciences, Lund University, Jan Waldenströms gata 35, CRC, Box 50332, 212 13, Malmö, Sweden
| | - Gunilla Nordin Fredrikson
- Dept. of Clinical Sciences, Lund University, Jan Waldenströms gata 35, CRC, Box 50332, 212 13, Malmö, Sweden
| | - Sarah Rogers
- ISIS Science and Technology Facilities Council, Harwell Science and Innovation Campus, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom
| | - Martine Moulin
- Life Science Group, Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, F-38042, Grenoble, Cedex 9, France
| | - Michael Haertlein
- Life Science Group, Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, F-38042, Grenoble, Cedex 9, France
| | - V Trevor Forsyth
- Life Science Group, Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, F-38042, Grenoble, Cedex 9, France.,Faculty of Natural Science and Institute for Science and Technology in Medicine, Keele University, Staffordshire, ST5 5BG, United Kingdom
| | - Markus R Wenk
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Thomas Günther Pomorski
- Dept. of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.,Dept. of Molecular Biochemistry, Ruhr University Bochum, Faculty of Chemistry and Biochemistry, 44780, Bochum, Germany
| | - Thomas Arnebrant
- Dept. of Biomedical Science, Malmö University, Per Albin Hanssons väg 35, 205 02, Malmö, Sweden
| | - Reidar Lund
- Dept. of Chemistry, University of Oslo, Blindern, 0315, Oslo, Norway
| | - Marité Cárdenas
- Dept. of Biomedical Science, Malmö University, Per Albin Hanssons väg 35, 205 02, Malmö, Sweden.
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The Production of Matchout-Deuterated Cholesterol and the Study of Bilayer-Cholesterol Interactions. Sci Rep 2019; 9:5118. [PMID: 30914734 PMCID: PMC6435723 DOI: 10.1038/s41598-019-41439-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/07/2019] [Indexed: 02/04/2023] Open
Abstract
The deuteration of biomolecules provides advanced opportunities for neutron scattering studies. For low resolution studies using techniques such as small-angle neutron scattering and neutron reflection, the level of deuteration of a sample can be varied to match the scattering length density of a specific D2O/H2O solvent mixture. This can be of major value in structural studies where specific regions of a complex system can be highlighted, and others rendered invisible. This is especially useful in analyses of the structure and dynamics of membrane components. In mammalian membranes, the presence of cholesterol is crucial in modulating the properties of lipids and in their interaction with proteins. Here, a protocol is described for the production of partially deuterated cholesterol which has a neutron scattering length density that matches that of 100% D2O solvent (hereby named matchout cholesterol). The level of deuteration was determined by mass spectrometry and nuclear magnetic resonance. The cholesterol match-point was verified experimentally using small angle neutron scattering. The matchout cholesterol was used to investigate the incorporation of cholesterol in various phosphatidylcholine supported lipid bilayers by neutron reflectometry. The study included both saturated and unsaturated lipids, as well as lipids with varying chain lengths. It was found that cholesterol is distributed asymmetrically within the bilayer, positioned closer to the headgroups of the lipids than to the middle of the tail core, regardless of the phosphatidylcholine species.
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Forsyth VT, Moody P. Neutron scattering for the study of biological systems - major opportunities within a rapidly changing landscape. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2018; 74:1126-1128. [PMID: 30605129 DOI: 10.1107/s2059798318017886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- V Trevor Forsyth
- Partnership for Structural Biology, Institut Laue-Langevin, 6 rue Jules Horowitz, 38042 Grenoble CEDEX 9 France
| | - Peter Moody
- Henry Wellcome Laboratories for Structural Biology, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Lancaster Road, Leicester LE1 7RH, UK
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The impact of deuteration on natural and synthetic lipids: A neutron diffraction study. Colloids Surf B Biointerfaces 2018; 168:126-133. [PMID: 29433911 DOI: 10.1016/j.colsurfb.2018.02.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 01/09/2018] [Accepted: 02/03/2018] [Indexed: 12/19/2022]
Abstract
The structural investigation of cellular membranes requires access to model systems where the molecular complexity is representative of the cellular environment and that allow for the exploitation of structural techniques. Neutron scattering, and in particular neutron diffraction can provide unique and detailed information on the structure of lipid membranes. However, deuterated samples are desirable to fully exploit this powerful method. Recently, the extraction of lipids from microorganisms grown in deuterated media was demonstrated to be both an attracting route to obtain complex lipid mixtures resembling the composition of natural membranes, and to producing deuterated molecules in a very convenient way. A full characterization of these deuterated extracts is hence pivotal for their use in building up model membrane systems. Here we report the structural characterization of lipid extracts obtained from Pichia pastoris by means of neutron diffraction measurements. In particular, we compare the structure of membranes extracted from yeast cells grown in a standard culture medium and in a corresponding deuterated culture medium. The results show that the different molecular composition of the deuterated and protiated lipid extracts induce different structural organization of the lipid membranes. In addition, we compare these membranes composed of extracted yeast lipids with stacked bilayers prepared from synthetic lipid mixtures.
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