1
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Cornet J, Coulonges N, Pezeshkian W, Penissat-Mahaut M, Desgrez-Dautet H, Marrink SJ, Destainville N, Chavent M, Manghi M. There and back again: bridging meso- and nano-scales to understand lipid vesicle patterning. SOFT MATTER 2024; 20:4998-5013. [PMID: 38884641 DOI: 10.1039/d4sm00089g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
We describe a complete methodology to bridge the scales between nanoscale molecular dynamics and (micrometer) mesoscale Monte Carlo simulations in lipid membranes and vesicles undergoing phase separation, in which curving molecular species are furthermore embedded. To go from the molecular to the mesoscale, we notably appeal to physical renormalization arguments enabling us to rigorously infer the mesoscale interaction parameters from its molecular counterpart. We also explain how to deal with the physical timescales at stake at the mesoscale. Simulating the as-obtained mesoscale system enables us to equilibrate the long wavelengths of the vesicles of interest, up to the vesicle size. Conversely, we then backmap from the meso- to the nano-scale, which enables us to equilibrate in turn the short wavelengths down to the molecular length-scales. By applying our approach to the specific situation of patterning a vesicle membrane, we show that macroscopic membranes can thus be equilibrated at all length-scales in achievable computational time offering an original strategy to address the fundamental challenge of timescale in simulations of large bio-membrane systems.
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Affiliation(s)
- Julie Cornet
- Laboratoire de Physique Théorique, Université de Toulouse, CNRS, UPS, France.
| | - Nelly Coulonges
- Laboratoire de Physique Théorique, Université de Toulouse, CNRS, UPS, France.
- Institut de Pharmacologie et Biologie Structurale, Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier, 31400, Toulouse, France.
| | - Weria Pezeshkian
- Niels Bohr International Academy, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - Maël Penissat-Mahaut
- Institut de Pharmacologie et Biologie Structurale, Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier, 31400, Toulouse, France.
| | - Hermes Desgrez-Dautet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | | | - Matthieu Chavent
- Institut de Pharmacologie et Biologie Structurale, Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier, 31400, Toulouse, France.
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France
| | - Manoel Manghi
- Laboratoire de Physique Théorique, Université de Toulouse, CNRS, UPS, France.
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2
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Spinozzi F, Moretti P, Perinelli DR, Corucci G, Piergiovanni P, Amenitsch H, Sancini GA, Franzese G, Blasi P. Small-angle X-ray scattering unveils the internal structure of lipid nanoparticles. J Colloid Interface Sci 2024; 662:446-459. [PMID: 38364470 DOI: 10.1016/j.jcis.2024.02.076] [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: 09/19/2023] [Revised: 02/01/2024] [Accepted: 02/06/2024] [Indexed: 02/18/2024]
Abstract
Lipid nanoparticles own a remarkable potential in nanomedicine, only partially disclosed. While the clinical use of liposomes and cationic lipid-nucleic acid complexes is well-established, liquid lipid nanoparticles (nanoemulsions), solid lipid nanoparticles, and nanostructured lipid carriers have even greater possibilities. However, they face obstacles in being used in clinics due to a lack of understanding about the molecular mechanisms controlling their drug loading and release, interactions with the biological environment (such as the protein corona), and shelf-life stability. To create effective drug delivery carriers and successfully translate bench research to clinical settings, it is crucial to have a thorough understanding of the internal structure of lipid nanoparticles. Through synchrotron small-angle X-ray scattering experiments, we determined the spatial distribution and internal structure of the nanoparticles' lipid, surfactant, and the bound water in them. The nanoparticles themselves have a barrel-like shape that consists of coplanar lipid platelets (specifically cetyl palmitate) that are covered by loosely spaced polysorbate 80 surfactant molecules, whose polar heads retain a large amount of bound water. To reduce the interface cost of bound water with unbound water without stacking, the platelets collapse onto each other. This internal structure challenges the classical core-shell model typically used to describe solid lipid nanoparticles and could play a significant role in drug loading and release, biological fluid interaction, and nanoparticle stability, making our findings valuable for the rational design of lipid-based nanoparticles.
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Affiliation(s)
- Francesco Spinozzi
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Italy.
| | - Paolo Moretti
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Italy
| | | | - Giacomo Corucci
- Institut Laue-Langevin, Grenoble, France; École Doctorale de Physique, Université Grenoble Alpes, Saint-Martin-d'Héres, France; Department of Chemistry, Imperial College London, London, UK
| | - Paolo Piergiovanni
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Italy
| | - Heinz Amenitsch
- Institute for Inorganic Chemistry, Graz University of Technology, Graz, Austria
| | | | - Giancarlo Franzese
- Secció de Física Estadística i Interdisciplinària, Departament de Física de la Matèria Condensada, & Institut de Nanociència i Nanotecnologia, Universitat de Barcelona, Martí i Franquès 1, Barcelona, 08028, Spain
| | - Paolo Blasi
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.
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3
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Thomas N, Combs W, Mandadapu KK, Agrawal A. Preferential electrostatic interactions of phosphatidic acid with arginines. SOFT MATTER 2024; 20:2998-3006. [PMID: 38482724 DOI: 10.1039/d4sm00088a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Phosphatidic acid (PA) is an anionic lipid that preferentially interacts with proteins in a diverse set of cellular processes such as transport, apoptosis, and neurotransmission. One such interaction is that of the PA lipids with the proteins of voltage-sensitive ion channels. In comparison to several other similarly charged anionic lipids, PA lipids exhibit much stronger interactions. Intrigued and motivated by this finding, we sought out to gain deeper understanding into the electrostatic interactions of anionic lipids with charged proteins. Using the voltage sensor domain (VSD) of the KvAP channel as a model system, we performed long-timescale atomistic simulations to analyze the interactions of POPA, POPG, and POPI lipids with arginines (ARGs). Our simulations reveal two mechanisms. First, POPA is able to interact not only with surface ARGs but is able to snorkel and interact with a buried arginine. POPG and POPI lipids on the other hand show weak interactions even with both the surface and buried ARGs. Second, deprotonated POPA with -2 charge is able to break the salt-bridge connection between VSD protein segments and establish its own electrostatic bond with the ARG. Based on these findings, we propose a headgroup size hypothesis for preferential solvation of proteins by charged lipids. These findings may be valuable in understanding how PA lipids could be modulating kinematics of transmembrane proteins in cellular membranes.
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Affiliation(s)
- Nidhin Thomas
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA.
| | - Wesley Combs
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA.
| | - Kranthi K Mandadapu
- Department of Chemical & Biomolecular Engineering, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, CA 94720, USA
| | - Ashutosh Agrawal
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA.
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4
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Semeraro EF, Frewein MPK, Pabst G. Structure of symmetric and asymmetric lipid membranes from joint SAXS/SANS. Methods Enzymol 2024; 700:349-383. [PMID: 38971607 DOI: 10.1016/bs.mie.2024.02.017] [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] [Indexed: 07/08/2024]
Abstract
Small-angle X-ray and neutron scattering (SAXS/SANS) techniques excel in unveiling intricate details of the internal structure of lipid membranes under physiologically relevant temperature and buffer conditions, all without the need to resort to bulky labels. By concurrently conducting and analyzing neutron and X-ray data, these methods harness the complete spectrum of contrast and resolution from various components constituting lipid membranes. Despite this, the literature exhibits only a sparse presence of applications compared to other techniques in membrane biophysics. This chapter serves as a primer for conducting joint SAXS/SANS analyses on symmetric and asymmetric large unilamellar vesicles, elucidating fundamental elements of the analysis process. Specifically, we introduce the basics of interactions of X-rays and neutrons with matter that lead to the scattering contrast and a description of membrane structure in terms of scattering length density profiles. These profiles allow fitting of the experimentally observed scattering intensity. We further integrate practical insights, unveiling strategies for successful data acquisition and providing a comprehensive assessment of the technique's advantages and drawbacks. By amalgamating theoretical underpinnings with practical considerations, this chapter aims to dismantle barriers hindering the adoption of joint SAXS/SANS approaches, thereby encouraging an influx of studies in this domain.
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Affiliation(s)
- Enrico F Semeraro
- Institute of Molecular Bioscience, NAWI Graz, University of Graz, Graz, Austria; Field of Excellence BioHealth-University of Graz, Graz, Austria
| | - Moritz P K Frewein
- Institute of Molecular Bioscience, NAWI Graz, University of Graz, Graz, Austria; Field of Excellence BioHealth-University of Graz, Graz, Austria
| | - Georg Pabst
- Institute of Molecular Bioscience, NAWI Graz, University of Graz, Graz, Austria; Field of Excellence BioHealth-University of Graz, Graz, Austria.
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5
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Engstedt J, Barauskas J, Kocherbitov V. Phase behavior of soybean phosphatidylcholine and glycerol dioleate in hydrated and dehydrated states studied by small-angle X-ray scattering. SOFT MATTER 2023; 19:8305-8317. [PMID: 37819242 DOI: 10.1039/d3sm01067h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Soybean phosphatidylcholine (SPC) and glycerol dioleate (GDO) form liquid crystal nanostructures in aqueous environments, and their mixtures can effectively encapsulate active pharmaceutical ingredients (API). When used in a subcutaneous environment, the liquid crystalline matrix gradually hydrates and degrades in the tissue whilst slowly releasing the API. Hydration dependent SPC/GDO phase behavior is complex, non-trivial, and still not fully understood. A deeper understanding of this system is important for controlling its function in drug delivery applications. The phase behavior of the mixture of SPC/GDO/water was studied as a function of hydration and lipid ratio. Small-angle X-ray scattering (SAXS) was used to identify space groups in liquid crystalline phases and to get detailed structural information on the isotropic reverse micellar phase. The reported pseudo ternary phase diagram includes eight different phases and numerous multiphase regions in a thermodynamically consistent way. For mixtures with SPC as the predominant component, the system presents a reverse hexagonal, lamellar and R3m phase. For mixtures with lower SPC concentrations, reverse cubic (Fd3m and Pm3n) as well as intermediate and isotropic micellar phases were identified. By modeling the SAXS data using a core-shell approach, the properties of the isotropic micellar phase were studied in detail as a function of concentration. Moreover, SAXS analysis of other phases revealed new structural features in relation to lipid-water interactions. The new improved ternary phase diagram offers valuable insight into the complex phase behavior of the SPC/GDO system. The detailed structural information is important for understanding what APIs can be incorporated in the liquid crystal structure.
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Affiliation(s)
- Jenni Engstedt
- Camurus AB, Ideon Science Park, Gamma Building, Sölvegatan 41, SE-22379 Lund, Sweden
- Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden.
- Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Justas Barauskas
- Camurus AB, Ideon Science Park, Gamma Building, Sölvegatan 41, SE-22379 Lund, Sweden
| | - Vitaly Kocherbitov
- Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden.
- Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
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6
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Lipowsky R, Ghosh R, Satarifard V, Sreekumari A, Zamaletdinov M, Różycki B, Miettinen M, Grafmüller A. Leaflet Tensions Control the Spatio-Temporal Remodeling of Lipid Bilayers and Nanovesicles. Biomolecules 2023; 13:926. [PMID: 37371505 PMCID: PMC10296112 DOI: 10.3390/biom13060926] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023] Open
Abstract
Biological and biomimetic membranes are based on lipid bilayers, which consist of two monolayers or leaflets. To avoid bilayer edges, which form when the hydrophobic core of such a bilayer is exposed to the surrounding aqueous solution, a single bilayer closes up into a unilamellar vesicle, thereby separating an interior from an exterior aqueous compartment. Synthetic nanovesicles with a size below 100 nanometers, traditionally called small unilamellar vesicles, have emerged as potent platforms for the delivery of drugs and vaccines. Cellular nanovesicles of a similar size are released from almost every type of living cell. The nanovesicle morphology has been studied by electron microscopy methods but these methods are limited to a single snapshot of each vesicle. Here, we review recent results of molecular dynamics simulations, by which one can monitor and elucidate the spatio-temporal remodeling of individual bilayers and nanovesicles. We emphasize the new concept of leaflet tensions, which control the bilayers' stability and instability, the transition rates of lipid flip-flops between the two leaflets, the shape transformations of nanovesicles, the engulfment and endocytosis of condensate droplets and rigid nanoparticles, as well as nanovesicle adhesion and fusion. To actually compute the leaflet tensions, one has to determine the bilayer's midsurface, which represents the average position of the interface between the two leaflets. Two particularly useful methods to determine this midsurface are based on the density profile of the hydrophobic lipid chains and on the molecular volumes.
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Affiliation(s)
- Reinhard Lipowsky
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Rikhia Ghosh
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
- Icahn School of Medicine Mount Sinai, New York, NY 10029, USA
| | - Vahid Satarifard
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
- Yale Institute for Network Science, Yale University, New Haven, CT 06520, USA
| | - Aparna Sreekumari
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
- Department of Physics, Indian Institute of Technology Palakkad, Palakkad 678 623, India
| | - Miftakh Zamaletdinov
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Bartosz Różycki
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Markus Miettinen
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
- Department of Chemistry, University of Bergen, 5020 Bergen, Norway
| | - Andrea Grafmüller
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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7
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Martin A, Jemmett PN, Howitt T, Wood MH, Burley AW, Cox LR, Dafforn TR, Welbourn RJL, Campana M, Skoda MW, Thompson JJ, Hussain H, Rawle JL, Carlà F, Nicklin CL, Arnold T, Horswell SL. Effect of Anionic Lipids on Mammalian Plasma Cell Membrane Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:2676-2691. [PMID: 36757323 PMCID: PMC9948536 DOI: 10.1021/acs.langmuir.2c03161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 01/19/2023] [Indexed: 06/18/2023]
Abstract
The effect of lipid composition on models of the inner leaflet of mammalian cell membranes has been investigated. Grazing incidence X-ray diffraction and X-ray and neutron reflectivity have been used to characterize lipid packing and solvation, while electrochemical and infrared spectroscopic methods have been employed to probe phase behavior in an applied electric field. Introducing a small quantity of the anionic lipid dimyristoylphosphatidylserine (DMPS) into bilayers of zwitterionic dimyristoylphosphatidylethanolamine (DMPE) results in a significant change in the bilayer response to an applied field: the tilt of the hydrocarbon chains increases before returning to the original tilt angle on detachment of the bilayer. Equimolar mixtures, with slightly closer chain packing, exhibit a similar but weaker response. The latter also tend to incorporate more solvent during this electrochemical phase transition, at levels similar to those of pure DMPS. Reflectivity measurements reveal greater solvation of lipid layers for DMPS > 30 mol %, matching the greater propensity for DMPS-rich bilayers to incorporate water. Taken together, the data indicate that the range of 10-35 mol % DMPS provides optimum bilayer properties (in flexibility and function as a barrier), which may explain why the DMPS content of cell membranes tends to be found within this range.
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Affiliation(s)
- Alexandra
L. Martin
- School of
Chemistry and School of Biosciences, University of Birmingham, Edgbaston, BirminghamB15 2TT, U.K.
| | - Philip N. Jemmett
- School of
Chemistry and School of Biosciences, University of Birmingham, Edgbaston, BirminghamB15 2TT, U.K.
| | - Thomas Howitt
- School of
Chemistry and School of Biosciences, University of Birmingham, Edgbaston, BirminghamB15 2TT, U.K.
| | - Mary H. Wood
- School of
Chemistry and School of Biosciences, University of Birmingham, Edgbaston, BirminghamB15 2TT, U.K.
| | - Andrew W. Burley
- School of
Chemistry and School of Biosciences, University of Birmingham, Edgbaston, BirminghamB15 2TT, U.K.
| | - Liam R. Cox
- School of
Chemistry and School of Biosciences, University of Birmingham, Edgbaston, BirminghamB15 2TT, U.K.
| | - Timothy R. Dafforn
- School of
Chemistry and School of Biosciences, University of Birmingham, Edgbaston, BirminghamB15 2TT, U.K.
| | - Rebecca J. L. Welbourn
- ISIS
Pulsed Neutron and Muon Source, Science
and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, OxfordshireOX11 0QX, U.K.
| | - Mario Campana
- ISIS
Pulsed Neutron and Muon Source, Science
and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, OxfordshireOX11 0QX, U.K.
| | - Maximilian W.
A. Skoda
- ISIS
Pulsed Neutron and Muon Source, Science
and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, OxfordshireOX11 0QX, U.K.
| | - Joseph J. Thompson
- Diamond
Light Source, Harwell Science and Innovation
Campus, Chilton, Didcot, OxfordshireOX11 0DE, U.K.
| | - Hadeel Hussain
- Diamond
Light Source, Harwell Science and Innovation
Campus, Chilton, Didcot, OxfordshireOX11 0DE, U.K.
| | - Jonathan L. Rawle
- Diamond
Light Source, Harwell Science and Innovation
Campus, Chilton, Didcot, OxfordshireOX11 0DE, U.K.
| | - Francesco Carlà
- Diamond
Light Source, Harwell Science and Innovation
Campus, Chilton, Didcot, OxfordshireOX11 0DE, U.K.
| | - Christopher L. Nicklin
- Diamond
Light Source, Harwell Science and Innovation
Campus, Chilton, Didcot, OxfordshireOX11 0DE, U.K.
| | - Thomas Arnold
- ISIS
Pulsed Neutron and Muon Source, Science
and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, OxfordshireOX11 0QX, U.K.
- Diamond
Light Source, Harwell Science and Innovation
Campus, Chilton, Didcot, OxfordshireOX11 0DE, U.K.
- European
Spallation Source ERIC PO Box 176, SE-221 00Lund, Sweden
- Department
of Chemistry, University of Bath, Claverton Down, BathBA2 7AY, U.K.
| | - Sarah L. Horswell
- School of
Chemistry and School of Biosciences, University of Birmingham, Edgbaston, BirminghamB15 2TT, U.K.
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8
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Spinozzi F, Alcaraz JP, Ortore MG, Gayet L, Radulescu A, Martin DK, Maccarini M. Small-Angle Neutron Scattering Reveals the Nanostructure of Liposomes with Embedded OprF Porins of Pseudomonas aeruginosa. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15026-15037. [PMID: 36459683 DOI: 10.1021/acs.langmuir.2c01342] [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 use of liposomes as drug delivery systems emerged in the last decades in view of their capacity and versatility to deliver a variety of therapeutic agents. By means of small-angle neutron scattering (SANS), we performed a detailed characterization of liposomes containing outer membrane protein F (OprF), the main porin of the Pseudomonas aeruginosa bacterium outer membrane. These OprF-liposomes are the basis of a novel vaccine against this antibiotic-resistant bacterium, which is one of the main hospital-acquired pathogens and causes each year a significant number of deaths. SANS data were analyzed by a specific model we created to quantify the crucial information about the structure of the liposome containing OprF, including the lipid bilayer structure, the amount of protein in the lipid bilayer, the average protein localization, and the effect of the protein incorporation on the lipid bilayer. Quantification of such structural information is important to enhance the design of liposomal delivery systems for therapeutic applications.
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Affiliation(s)
- Francesco Spinozzi
- Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Jean-Pierre Alcaraz
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Maria Grazia Ortore
- Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Landry Gayet
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Aurel Radulescu
- Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, 85748 Garching, Germany
| | - Donald K Martin
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Marco Maccarini
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
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9
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Heller WT. Small-Angle Neutron Scattering for Studying Lipid Bilayer Membranes. Biomolecules 2022; 12:1591. [PMID: 36358941 PMCID: PMC9687511 DOI: 10.3390/biom12111591] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/18/2022] [Accepted: 10/26/2022] [Indexed: 09/23/2023] Open
Abstract
Small-angle neutron scattering (SANS) is a powerful tool for studying biological membranes and model lipid bilayer membranes. The length scales probed by SANS, being from 1 nm to over 100 nm, are well-matched to the relevant length scales of the bilayer, particularly when it is in the form of a vesicle. However, it is the ability of SANS to differentiate between isotopes of hydrogen as well as the availability of deuterium labeled lipids that truly enable SANS to reveal details of membranes that are not accessible with the use of other techniques, such as small-angle X-ray scattering. In this work, an overview of the use of SANS for studying unilamellar lipid bilayer vesicles is presented. The technique is briefly presented, and the power of selective deuteration and contrast variation methods is discussed. Approaches to modeling SANS data from unilamellar lipid bilayer vesicles are presented. Finally, recent examples are discussed. While the emphasis is on studies of unilamellar vesicles, examples of the use of SANS to study intact cells are also presented.
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Affiliation(s)
- William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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10
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Watkins EB, Dennison AJC, Majewski J. Binding of Cholera Toxin B-Subunit to a Ganglioside GM1-Functionalized PEG-Tethered Lipid Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6959-6966. [PMID: 35604017 PMCID: PMC9179658 DOI: 10.1021/acs.langmuir.2c00499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/10/2022] [Indexed: 05/25/2023]
Abstract
We report neutron reflectometry (NR) studies of polyethylene glycol (PEG)-tethered model lipid membranes at the solid-liquid interface and of cholera toxin's B-subunit (CTxB) binding to tethered membranes containing ganglioside GM1 receptors. First, tethered polymer brushes were formed by grafting silane-functionalized PEG lipopolymers to quartz from solution. Subsequent deposition of lipids by Langmuir-Blodgett/Langmuir-Schaefer (LB/LS) resulted in a tethered bilayer structure separated from the solid support by a hydrated PEG layer. NR revealed that the tethers formed a highly hydrated polymer brush, uniformly separating the bilayer from the underlying solid substrate. Further, the lipid bilayer did not significantly perturb the brush's conformation relative to a free brush. Biological functionality of the tethered bilayers was verified by interacting CTxB, with ganglioside GM1 receptors incorporated into the bilayer. The surface coverage of CTxB bound to the lipid membrane, θCTB= 0.58 ± 0.08, was consistent with the coverage predicted for random sequential absorption, and toxin binding did not impact the membrane conformation.
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Affiliation(s)
- Erik B. Watkins
- MPA-11:
Materials Synthesis and Integrated Devices, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Institut
Laue-Langevin, BP 156, 38042 Grenoble, France
| | - Andrew J. C. Dennison
- Dept.
Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7HG, U.K.
| | - Jaroslaw Majewski
- Division
of Molecular and Cellular Biosciences, National
Science Foundation, Alexandria 22303, Virginia, United States
- Theoretical
Biology and Biophysics at Los Alamos National Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Department
of Chemical and Biological Engineering and Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
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11
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Leite NB, Martins DB, Alvares DS, Cabrera MPDS. Quercetin induces lipid domain-dependent permeability. Chem Phys Lipids 2021; 242:105160. [PMID: 34808124 DOI: 10.1016/j.chemphyslip.2021.105160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 01/08/2023]
Abstract
Quercetin is a polyphenolic molecule with a broad spectrum of biological activities derived from its antioxidant property. Its mechanism of action has been explained by its binding and/or interference with enzymes, receptors, transporters and signal transduction systems. Since these important mechanisms generally occur in membrane environments, within and through lipid bilayers, investigating the biophysical properties related to the diversity of lipid compositions of cell membranes may be the key to understanding the role of cell membrane in these processes. In this work, we explored the interaction of quercetin with model membranes of different lipid compositions to access the importance of lipid phases and bilayer homogeneity to the action of quercetin and contribute to the understanding of quercetin multiple activities. Analysis of the influence of quercetin on the morphology and permeability of GUVs, the rigidity of LUVs and affinity to these vesicles showed that quercetin strongly partitions to the more homogeneous environments, but significantly permeates and modifies the more heterogeneous where liquid-disordered, liquid-ordered and solid phases coexist. Our findings support the condensing effect of quercetin, which is observed through a significant rigidifying of bilayers containing 40% cholesterol, but much less evidenced when it is reduced to 20% or in its absence. Nevertheless, the presence of sphingomyelin in the ternary system led to a more heterogeneous bilayer with the formation of micrometric and probably also nanometric domains, which coalesce in the presence of quercetin. This observation together with increased permeability points to an insertion effect.
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Affiliation(s)
- Natália Bueno Leite
- Departamento de Química e Ciências Ambientais, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), Câmpus São José do Rio Preto, SP, Brazil.
| | - Danubia Batista Martins
- Departamentode Física, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), Câmpus São José do Rio Preto, SP, Brazil
| | - Dayane S Alvares
- Departamentode Física, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), Câmpus São José do Rio Preto, SP, Brazil
| | - Marcia Perez Dos Santos Cabrera
- Departamento de Química e Ciências Ambientais, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), Câmpus São José do Rio Preto, SP, Brazil; Departamentode Física, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), Câmpus São José do Rio Preto, SP, Brazil
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12
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Seper BC, Ko A, Abma AF, Folkerts AD, Tristram-Nagle S, Harper PE. Methylene volumes in monoglyceride bilayers are larger than in liquid alkanes. Chem Phys Lipids 2019; 226:104833. [PMID: 31738879 DOI: 10.1016/j.chemphyslip.2019.104833] [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: 07/29/2019] [Revised: 09/26/2019] [Accepted: 10/09/2019] [Indexed: 11/26/2022]
Abstract
The densities as a function of temperature of four fully hydrated saturated monoglycerides with even chain lengths ranging from eight to fourteen were determined by vibrating tube densitometry and their phase transition temperatures were determined by differential scanning calorimetry (DSC). We find the volume of a methylene group in a monoglyceride bilayer is 2% larger than in liquid alkanes at physiological temperatures, similar to the methylene group volumes found in phosphatidylcholine (PC) bilayers. Additionally, we carefully consider the traditional method of calculating component volumes from experimental data and note potential difficulties in this approach. In the literature, the ratio of terminal methyl volume (CH3) to methylene (CH2) volumes is typically assumed to be 2. By analysis of literature alkane data, we find this ratio actually ranges from 1.9 to 2.3 for temperatures ranging from 0 °C to 100 °C. For a rough sense of scale, we note that to effect a 2% reduction in volume requires of order 200 atmospheres of pressure, and pressures of this magnitude are biologically relevant. For instance, this amount of pressure is sufficient to reverse the effect of anesthesia. The component volumes obtained are an important parameter used for determining the structure of lipid bilayers and for molecular dynamics simulations.
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Affiliation(s)
- Brian C Seper
- Department of Physics and Astronomy, Calvin University, Grand Rapids, MI 49546, USA
| | - Anthony Ko
- Biological Physics Group, Physics Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
| | - Aaron F Abma
- Department of Physics and Astronomy, Calvin University, Grand Rapids, MI 49546, USA
| | - Andrew D Folkerts
- Department of Physics and Astronomy, Calvin University, Grand Rapids, MI 49546, USA
| | - Stephanie Tristram-Nagle
- Biological Physics Group, Physics Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
| | - Paul E Harper
- Department of Physics and Astronomy, Calvin University, Grand Rapids, MI 49546, USA.
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13
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Ortiz-Collazos S, Picciani PH, Oliveira ON, Pimentel AS, Edler KJ. Influence of levofloxacin and clarithromycin on the structure of DPPC monolayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:182994. [DOI: 10.1016/j.bbamem.2019.05.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 05/20/2019] [Accepted: 05/22/2019] [Indexed: 12/11/2022]
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14
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Watanabe N, Suga K, Slotte JP, Nyholm TKM, Umakoshi H. Lipid-Surrounding Water Molecules Probed by Time-Resolved Emission Spectra of Laurdan. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:6762-6770. [PMID: 31021095 DOI: 10.1021/acs.langmuir.9b00303] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The hydration states of the interfacial region of lipid bilayers were investigated on the basis of the time-resolved emission spectra (TRES) analysis of 6-lauroyl-2-dimethylamino naphthalene (Laurdan), a common fluorescence probe used to analyze membrane hydration. TRES derived from long and short lifetime components were extracted from samples of different lipid species: 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl- sn-glycero-3-phosphocholine (DOPC), d- erythro- N-palmitoyl-sphingosylphosphorylcholine (PSM), and a DOPC/PSM binary bilayer system. Neither lifetime component (short or long) corresponded with the hydration properties; the short lifetime component of DOPC (1.97 ns) exhibited a peak at 440 nm, and the long lifetime components of DPPC and PSM (7.76 and 7.77 ns, respectively) exhibited peaks at the same wavelength. This similarity arose from the competition between the collisional quenching and the hydration effects of water molecules. Herein, this phenomenon was investigated using a plot of the lifetime τ and the peak position λ (τ vs λ plot), simultaneously visualizing both effects by deconvoluting the TRES. On the basis of collisional quenching theory, the distribution of the water population per lipid (water map) was generated. According to this theory, the τ vs λ plot was applied to the water map and the calculation of the number of water molecules per lipid, which is consistent with previous reports. This approach provides novel insights for the analysis of molecular hydration states using the fluorescence of Laurdan.
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Affiliation(s)
- Nozomi Watanabe
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
| | - Keishi Suga
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
| | - J Peter Slotte
- Biochemistry, Faculty of Science and Engineering , Åbo Akademi University , Tykistökatu 6A , Turku FI-20520 , Finland
| | - Thomas K M Nyholm
- Biochemistry, Faculty of Science and Engineering , Åbo Akademi University , Tykistökatu 6A , Turku FI-20520 , Finland
| | - Hiroshi Umakoshi
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
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15
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Baccile N, Delbeke EIP, Brennich M, Seyrig C, Everaert J, Roelants SLKW, Soetaert W, Van Bogaert INA, Van Geem KM, Stevens CV. Asymmetrical, Symmetrical, Divalent, and Y-Shaped (Bola)amphiphiles: The Relationship between the Molecular Structure and Self-Assembly in Amino Derivatives of Sophorolipid Biosurfactants. J Phys Chem B 2019; 123:3841-3858. [DOI: 10.1021/acs.jpcb.9b01013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Niki Baccile
- Sorbonne Université,
Centre National de la Recherche Scientifique, Laboratoire de Chimie
de la Matière Condensée de Paris, LCMCP, F-75005 Paris, France
| | - Elisabeth I. P. Delbeke
- Laboratory for Chemical Technology (LCT), Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 125, 9052 Ghent, Belgium
| | - Martha Brennich
- European Molecular Biology Laboratory, Synchrotron Crystallography Group, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Chloé Seyrig
- Sorbonne Université,
Centre National de la Recherche Scientifique, Laboratoire de Chimie
de la Matière Condensée de Paris, LCMCP, F-75005 Paris, France
| | | | | | - Wim Soetaert
- Bio Base Europe Pilot Plant (BBEU), Rodenhuizenkaai 1, 9042 Ghent (Desteldonk), Belgium
| | | | - Kevin M. Van Geem
- Laboratory for Chemical Technology (LCT), Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 125, 9052 Ghent, Belgium
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16
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Enhanced Ordering in Monolayers Containing Glycosphingolipids: Impact of Carbohydrate Structure. Biophys J 2019. [PMID: 29539397 DOI: 10.1016/j.bpj.2017.12.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The influence of carbohydrate structure on the ordering of glycosphingolipids (GSLs) and surrounding phospholipids was investigated in monolayers at the air-water interface. Binary mixtures composed of GSLs, chosen to span a range of carbohydrate complexity, and zwitterionic dipalmitoylphosphatidylcholine phospholipid, were studied. X-ray reflectivity was used to measure the out-of-plane structure of the monolayers and characterize the extension and conformation of the GSL carbohydrates. Using synchrotron grazing incidence x-ray diffraction, the in-plane packing of the lipid acyl chains and the area per molecule within ordered domains were characterized at different mole ratios of the two components. Our findings indicate that GSL-containing mixtures, regardless of the carbohydrate size, enhance the ordering of the surrounding lipids, resulting in a larger fraction of ordered phase of the monolayer and greater dimensions of the ordered domains. Reduction of the averaged area per molecule within the ordered domains was also observed but only in the cases where there was a size mismatch between the phospholipid headgroups and GSL components, suggesting that the condensation mechanism involves the relief of steric interactions between headgroups in mixtures.
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17
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McCluskey AR, Sanchez-Fernandez A, Edler KJ, Parker SC, Jackson AJ, Campbell RA, Arnold T. Bayesian determination of the effect of a deep eutectic solvent on the structure of lipid monolayers. Phys Chem Chem Phys 2019; 21:6133-6141. [DOI: 10.1039/c9cp00203k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A novel reflectometry analysis method reveals the structure of lipid monolayers at the air-DES interface.
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Affiliation(s)
| | | | | | | | - Andrew J. Jackson
- European Spallation Source
- SE-211 00 Lund
- Sweden
- Department of Physical Chemistry
- Lund University
| | - Richard A. Campbell
- Division of Pharmacy and Optometry
- University of Manchester
- Manchester
- UK
- Institut Laue-Langevin
| | - Thomas Arnold
- Department of Chemistry
- University of Bath
- Bath
- UK
- Diamond Light Source
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18
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Campbell RA, Saaka Y, Shao Y, Gerelli Y, Cubitt R, Nazaruk E, Matyszewska D, Lawrence MJ. Structure of surfactant and phospholipid monolayers at the air/water interface modeled from neutron reflectivity data. J Colloid Interface Sci 2018; 531:98-108. [DOI: 10.1016/j.jcis.2018.07.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/06/2018] [Accepted: 07/06/2018] [Indexed: 10/28/2022]
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19
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Hydroperoxide and carboxyl groups preferential location in oxidized biomembranes experimentally determined by small angle X-ray scattering: Implications in membrane structure. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2299-2307. [DOI: 10.1016/j.bbamem.2018.05.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/26/2018] [Accepted: 05/24/2018] [Indexed: 01/28/2023]
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20
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Sreekumari A, Lipowsky R. Lipids with bulky head groups generate large membrane curvatures by small compositional asymmetries. J Chem Phys 2018; 149:084901. [PMID: 30193489 DOI: 10.1063/1.5038427] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Glycolipids such as GM1 have bulky head groups consisting of several monosaccharides. When these lipids are added to phospholipid bilayers, they generate large membrane curvatures even for small compositional asymmetries between the two leaflets of the bilayers. On the micrometer scale, these bilayer asymmetries lead to the spontaneous tubulation of giant vesicles as recently observed by optical microscopy. Here, we study these mixed membranes on the nanometer scale using coarse-grained molecular simulations. The membrane composition is defined by the mole fractions ϕ1 and ϕ2 of the large-head lipid in the two leaflets of the bilayer. Symmetric membranes are obtained for ϕ1 = ϕ2 ≡ ϕle, and asymmetric ones for ϕ1 ≠ ϕ2. In both cases, we compute the density and stress profiles across the membranes. The stress profiles are used to identify the tensionless states of the membranes. Symmetric and tensionless bilayers are found to be stable within the whole composition range 0 ≤ ϕle ≤ 1. For these symmetric bilayers, both the area compressibility modulus and the bending rigidity are found to vary non-monotonically with the leaflet mole fraction ϕle. For asymmetric bilayers, we compute the product of bending rigidity and spontaneous curvature from the first moment of the stress profile and determine the bending rigidities of the asymmetric membranes using the ϕle-dependent rigidities of the single leaflets. When we combine these results, the compositional asymmetry ϕ1 - ϕ2 is found to generate the spontaneous curvature (ϕ1 - ϕ2)/(0.63 ℓme) with the membrane thickness ℓme ≃ 4 nm. Therefore, the spontaneous curvature increases linearly with the compositional asymmetry. Furthermore, the small compositional asymmetry ϕ1 - ϕ2 = 0.04 leads to the large spontaneous curvature 1/(63 nm) and the increased asymmetry ϕ1 - ϕ2 = 0.2 generates the huge spontaneous curvature 1/(13 nm). These large values of the spontaneous curvature will facilitate future simulation studies of various membrane processes such as bud formation and nanoparticle engulfment.
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Affiliation(s)
- Aparna Sreekumari
- Theory and Bio-systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Reinhard Lipowsky
- Theory and Bio-systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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21
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Moulin M, Strohmeier GA, Hirz M, Thompson KC, Rennie AR, Campbell RA, Pichler H, Maric S, Forsyth VT, Haertlein M. Perdeuteration of cholesterol for neutron scattering applications using recombinant Pichia pastoris. Chem Phys Lipids 2018; 212:80-87. [PMID: 29357283 DOI: 10.1016/j.chemphyslip.2018.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/20/2017] [Accepted: 01/15/2018] [Indexed: 02/08/2023]
Abstract
Deuteration of biomolecules has a major impact on both quality and scope of neutron scattering experiments. Cholesterol is a major component of mammalian cells, where it plays a critical role in membrane permeability, rigidity and dynamics, and contributes to specific membrane structures such as lipid rafts. Cholesterol is the main cargo in low and high-density lipoprotein complexes (i.e. LDL, HDL) and is directly implicated in several pathogenic conditions such as coronary artery disease which leads to 17 million deaths annually. Neutron scattering studies on membranes or lipid-protein complexes exploiting contrast variation have been limited by the lack of availability of fully deuterated biomolecules and especially perdeuterated cholesterol. The availability of perdeuterated cholesterol provides a unique way of probing the structural and dynamical properties of the lipoprotein complexes that underly many of these disease conditions. Here we describe a procedure for in vivo production of perdeuterated recombinant cholesterol in lipid-engineered Pichia pastoris using flask and fed-batch fermenter cultures in deuterated minimal medium. Perdeuteration of the purified cholesterol was verified by mass spectrometry and its use in a neutron scattering study was demonstrated by neutron reflectometry measurements using the FIGARO instrument at the ILL.
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Affiliation(s)
- Martine Moulin
- Institut Laue-Langevin, 71, Avenue des Martyrs, Grenoble 38042, France; Faculty of Natural Sciences, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
| | - Gernot A Strohmeier
- acib, Austrian Centre of Industrial Biotechnology GmbH, 8010 Graz, Austria; Institute of Organic Chemistry, NAWI Graz, Graz University of Technology, 8010 Graz, Austria
| | - Melanie Hirz
- Institute of Molecular Biotechnology, NAWI Graz, BioTechMed Graz, Graz University of Technology, 8010 Graz, Austria
| | - Katherine C Thompson
- Department of Biological Sciences and Institute of Structural and Molecular Biology, Birkbeck College, University of London, Malet Street, London WC1E 7HX, United Kingdom
| | - Adrian R Rennie
- Centre for Neutron Scattering, Uppsala University, 751 20 Uppsala, Sweden
| | | | - Harald Pichler
- acib, Austrian Centre of Industrial Biotechnology GmbH, 8010 Graz, Austria; Institute of Molecular Biotechnology, NAWI Graz, BioTechMed Graz, Graz University of Technology, 8010 Graz, Austria
| | - Selma Maric
- Biofilms - Research Centre for Biointerfaces and Biomedical Science Department, Faculty of Health and Society, Malmö University, Malmö 20506, Sweden
| | - V Trevor Forsyth
- Institut Laue-Langevin, 71, Avenue des Martyrs, Grenoble 38042, France; Faculty of Natural Sciences, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
| | - Michael Haertlein
- Institut Laue-Langevin, 71, Avenue des Martyrs, Grenoble 38042, France.
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22
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Micciulla S, Gerelli Y, Campbell RA, Schneck E. A Versatile Method for the Distance-Dependent Structural Characterization of Interacting Soft Interfaces by Neutron Reflectometry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:789-800. [PMID: 29039954 DOI: 10.1021/acs.langmuir.7b02971] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Interactions between soft interfaces govern the behavior of emulsions and foams and crucially influence the functions of biological entities like membranes. To understand the character of these interactions, detailed insight into the interfaces' structural response in terms of molecular arrangements and conformations is often essential. This requires the realization of controlled interaction conditions and surface-sensitive techniques capable of resolving the structure of buried interfaces. Here, we present a new approach to determine the distance-dependent structure of interacting soft interfaces by neutron reflectometry. A solid/water interface and a water/oil interface are functionalized independently and initially macroscopically separated. They are then brought into contact and structurally characterized under interacting conditions. The nanometric distance between the two interfaces can be varied via the exertion of osmotic pressures. Our first experiments on lipid-anchored polymer brushes interacting across water with solid-grafted polyelectrolyte brushes and with bare silicon surfaces reveal qualitatively different interaction scenarios depending on the chemical composition of the two involved interfaces.
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Affiliation(s)
- Samantha Micciulla
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam, Germany
- Institut Laue-Langevin , 38000 Grenoble, France
| | | | | | - Emanuel Schneck
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam, Germany
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23
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Sørensen HV, Pedersen JN, Pedersen JS, Otzen DE. Tailoring thermal treatment to form liprotide complexes between oleic acid and different proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:682-693. [DOI: 10.1016/j.bbapap.2017.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 03/05/2017] [Accepted: 03/24/2017] [Indexed: 10/19/2022]
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24
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Hazell G, Arnold T, Barker RD, Clifton LA, Steinke NJ, Tognoloni C, Edler KJ. Evidence of Lipid Exchange in Styrene Maleic Acid Lipid Particle (SMALP) Nanodisc Systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11845-11853. [PMID: 27739678 DOI: 10.1021/acs.langmuir.6b02927] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Styrene-alt-maleic acid lipid particles (SMALPs) are self-assembled discoidal structures composed of a polymer belt and a segment of lipid bilayer, which are capable of encapsulating membrane proteins directly from the cell membrane. Here we present evidence of the exchange of lipids between such "nanodiscs" and lipid monolayers adsorbed at either solid-liquid or air-liquid interfaces. This behavior has important implications for the potential uses of nanodiscs.
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Affiliation(s)
- Gavin Hazell
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom
| | - Thomas Arnold
- Diamond Light Source, Harwell Science and Innovation Campus , Didcot, OX11 ODE, United Kingdom
| | - Robert D Barker
- School of Science and Engineering, University of Dundee , Dundee, DD1 4HN, United Kingdom
| | - Luke A Clifton
- ISIS Spallation Neutron Source, STFC, Harwell Science and Innovation Campus, Didcot, OX11 OQX, United Kingdom
| | - Nina-Juliane Steinke
- ISIS Spallation Neutron Source, STFC, Harwell Science and Innovation Campus, Didcot, OX11 OQX, United Kingdom
| | - Cecilia Tognoloni
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom
| | - Karen J Edler
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom
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25
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Therrien A, Lafleur M. Melittin-Induced Lipid Extraction Modulated by the Methylation Level of Phosphatidylcholine Headgroups. Biophys J 2016; 110:400-410. [PMID: 26789763 DOI: 10.1016/j.bpj.2015.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 12/03/2015] [Accepted: 12/07/2015] [Indexed: 01/06/2023] Open
Abstract
Protein- and peptide-induced lipid extraction from membranes is a critical process for many biological events, including reverse cholesterol transport and sperm capacitation. In this work, we examine whether such processes could display specificity for some lipid species. Melittin, the main component of dry bee venom, was used as a model amphipathic α-helical peptide. We specifically determined the modulation of melittin-induced lipid extraction from membranes by the change of the methylation level of phospholipid headgroups. Phosphatidylcholine (PC) bilayers were demethylated either by substitution with phosphatidylethanolamine (PE) or chemically by using mono- and dimethylated PE. It is shown that demethylation reduces the association of melittin with membranes, likely because of the resulting tighter chain packing of the phospholipids, which reduces the capacity of the membranes to accommodate inserted melittin. This reduced binding of the peptide is accompanied by an inhibition of the lipid extraction caused by melittin. We demonstrate that melittin selectively extracts PC from PC/PE membranes. This selectivity is proposed to be a consequence of a PE depletion in the surroundings of bound melittin to minimize disruption of the interphospholipid interactions. The resulting PC-enriched vicinity of melittin would be responsible for the observed formation of PC-enriched lipid/peptide particles resulting from the lipid efflux. These findings reveal that modulating the methylation level of phospholipid headgroups is a simple way to control the specificity of lipid extraction from membranes by peptides/proteins and thereby modulate the lipid composition of the membranes.
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Affiliation(s)
- Alexandre Therrien
- Department of Chemistry, Center for Self-Assembled Chemical Structures, Université de Montréal, Montréal, Québec, Canada
| | - Michel Lafleur
- Department of Chemistry, Center for Self-Assembled Chemical Structures, Université de Montréal, Montréal, Québec, Canada.
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26
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Marsh D. Equation of State for Phospholipid Self-Assembly. Biophys J 2016; 110:188-96. [PMID: 26745421 DOI: 10.1016/j.bpj.2015.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/09/2015] [Accepted: 11/09/2015] [Indexed: 11/16/2022] Open
Abstract
Phospholipid self-assembly is the basis of biomembrane stability. The entropy of transfer from water to self-assembled micelles of lysophosphatidylcholines and diacyl phosphatidylcholines with different chain lengths converges to a common value at a temperature of 44°C. The corresponding enthalpies of transfer converge at ∼-18°C. An equation of state for the free energy of self-assembly formulated from this thermodynamic data depends on the heat capacity of transfer as the sole parameter needed to specify a particular lipid. For lipids lacking calorimetric data, measurement of the critical micelle concentration at a single temperature suffices to define an effective heat capacity according to the model. Agreement with the experimental temperature dependence of the critical micelle concentration is then good. The predictive powers should extend also to amphiphile partitioning and the kinetics of lipid-monomer transfer.
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Affiliation(s)
- Derek Marsh
- University of Southern Denmark, MEMPHYS, Odense, Denmark; Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.
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27
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Poger D, Caron B, Mark AE. Validating lipid force fields against experimental data: Progress, challenges and perspectives. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1556-65. [DOI: 10.1016/j.bbamem.2016.01.029] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 01/07/2016] [Accepted: 01/27/2016] [Indexed: 01/16/2023]
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28
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Salim M, Wan Iskandar WFN, Patrick M, Zahid NI, Hashim R. Swelling of Bicontinuous Cubic Phases in Guerbet Glycolipid: Effects of Additives. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5552-61. [PMID: 27183393 DOI: 10.1021/acs.langmuir.6b01007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Inverse bicontinuous cubic phases of lyotropic liquid crystal self-assembly have received much attention in biomedical, biosensing, and nanotechnology applications. An Ia3d bicontinuous cubic based on the gyroid G-surface can be formed by the Guerbet synthetic glucolipid 2-hexyl-decyl-β-d-glucopyranoside (β-Glc-OC6C10) in excess water. The small water channel diameter of this cubic phase could provide nanoscale constraints in encapsulation of large molecules and crystallization of membrane proteins, hence stresses the importance of water channel tuning ability. This work investigates the swelling behavior of lyotropic self-assembly of β-Glc-OC6C10 which could be controlled and modulated by different surfactants as a hydration-modulating agent. Our results demonstrate that addition of nonionic glycolipid octyl-β-d-glucopyranoside (β-Glc-OC8) at 20 and 25 mol % gives the largest attainable cubic water channel diameter of ca. 62 Å, and formation of coacervates which may be attributed to a sponge phase were seen at 20 mol % octyl-β-d-maltopyranoside (β-Mal-OC8). Swelling of the cubic water channel can also be attained in charged surfactant-doped systems dioctyl sodium sulfosuccinate (AOT) and hexadecyltrimethylammonium bromide (CTAB), of which phase transition occurred from cubic to a lamellar phase. Destabilization of the cubic phase to an inverse hexagonal phase was observed when a high amount of charged lecithin (LEC) and stearylamine (SA) was added to the lipid self-assembly.
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Affiliation(s)
- Malinda Salim
- Center of Fundamental Science of Self-Assembly, Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Wan Farah Nasuha Wan Iskandar
- Center of Fundamental Science of Self-Assembly, Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Melonney Patrick
- Center of Fundamental Science of Self-Assembly, Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - N Idayu Zahid
- Center of Fundamental Science of Self-Assembly, Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
| | - Rauzah Hashim
- Center of Fundamental Science of Self-Assembly, Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia
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Achilles A, Bärenwald R, Lechner BD, Werner S, Ebert H, Tschierske C, Blume A, Bacia K, Saalwächter K. Self-Assembly of X-Shaped Bolapolyphiles in Lipid Membranes: Solid-State NMR Investigations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:673-682. [PMID: 26735449 DOI: 10.1021/acs.langmuir.5b03712] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A novel class of rigid-rod bolapolyphilic molecules with three philicities (rigid aromatic core, mobile aliphatic side chains, polar end groups) has recently been demonstrated to incorporate into and span lipid membranes, and to exhibit a rich variety of self-organization modes, including macroscopically ordered snowflake structures with 6-fold symmetry. In order to support a structural model and to better understand the self-organization on a molecular scale, we here report on proton and carbon-13 high-resolution magic-angle spinning solid-state NMR investigations of two different bolapolyphiles (BPs) in model membranes of two different phospholipids (DPPC, DOPC). We elucidate the changes in molecular dynamics associated with three new phase transitions detected by calorimetry in composite membranes of different composition, namely, a change in π-π-packing, the melting of lipid tails associated with the superstructure, and the dissolution and onset of free rotation of the BPs. We derive dynamic order parameters associated with different H-H and C-H bond directions of the BPs, demonstrating that the aromatic cores are well packed below the final phase transition, showing only 180° flips of the phenyl ring, and that they perform free rotations with additional oscillations of the long axis when dissolved in the fluid membrane. Our data suggests that BPs not only form ordered superstructures, but also rather homogeneously dispersed π-packed filaments within the lipid gel phase, thus reducing the corrugation of large vesicles.
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Affiliation(s)
- Anja Achilles
- Institut für Physik - NMR, ‡Institut für Chemie - Physikalische Chemie, §ZIK HALOmem, and ∥Institut für Chemie - Organische Chemie, Martin-Luther-Universität Halle-Wittenberg , D-06120 Halle, Germany
| | - Ruth Bärenwald
- Institut für Physik - NMR, ‡Institut für Chemie - Physikalische Chemie, §ZIK HALOmem, and ∥Institut für Chemie - Organische Chemie, Martin-Luther-Universität Halle-Wittenberg , D-06120 Halle, Germany
| | - Bob-Dan Lechner
- Institut für Physik - NMR, ‡Institut für Chemie - Physikalische Chemie, §ZIK HALOmem, and ∥Institut für Chemie - Organische Chemie, Martin-Luther-Universität Halle-Wittenberg , D-06120 Halle, Germany
| | - Stefan Werner
- Institut für Physik - NMR, ‡Institut für Chemie - Physikalische Chemie, §ZIK HALOmem, and ∥Institut für Chemie - Organische Chemie, Martin-Luther-Universität Halle-Wittenberg , D-06120 Halle, Germany
| | - Helgard Ebert
- Institut für Physik - NMR, ‡Institut für Chemie - Physikalische Chemie, §ZIK HALOmem, and ∥Institut für Chemie - Organische Chemie, Martin-Luther-Universität Halle-Wittenberg , D-06120 Halle, Germany
| | - Carsten Tschierske
- Institut für Physik - NMR, ‡Institut für Chemie - Physikalische Chemie, §ZIK HALOmem, and ∥Institut für Chemie - Organische Chemie, Martin-Luther-Universität Halle-Wittenberg , D-06120 Halle, Germany
| | - Alfred Blume
- Institut für Physik - NMR, ‡Institut für Chemie - Physikalische Chemie, §ZIK HALOmem, and ∥Institut für Chemie - Organische Chemie, Martin-Luther-Universität Halle-Wittenberg , D-06120 Halle, Germany
| | - Kirsten Bacia
- Institut für Physik - NMR, ‡Institut für Chemie - Physikalische Chemie, §ZIK HALOmem, and ∥Institut für Chemie - Organische Chemie, Martin-Luther-Universität Halle-Wittenberg , D-06120 Halle, Germany
| | - Kay Saalwächter
- Institut für Physik - NMR, ‡Institut für Chemie - Physikalische Chemie, §ZIK HALOmem, and ∥Institut für Chemie - Organische Chemie, Martin-Luther-Universität Halle-Wittenberg , D-06120 Halle, Germany
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30
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Marquardt D, Heberle FA, Nickels JD, Pabst G, Katsaras J. On scattered waves and lipid domains: detecting membrane rafts with X-rays and neutrons. SOFT MATTER 2015; 11:9055-72. [PMID: 26428538 PMCID: PMC4719199 DOI: 10.1039/c5sm01807b] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 09/21/2015] [Indexed: 05/28/2023]
Abstract
In order to understand the biological role of lipids in cell membranes, it is necessary to determine the mesoscopic structure of well-defined model membrane systems. Neutron and X-ray scattering are non-invasive, probe-free techniques that have been used extensively in such systems to probe length scales ranging from angstroms to microns, and dynamics occurring over picosecond to millisecond time scales. Recent developments in the area of phase separated lipid systems mimicking membrane rafts will be presented, and the underlying concepts of the different scattering techniques used to study them will be discussed in detail.
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Affiliation(s)
- Drew Marquardt
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, Humboldtstr. 50/III, Graz, Austria. and BioTechMed-Graz, Graz, Austria
| | - Frederick A Heberle
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. and Joint Institute for Neutron Sciences, Oak Ridge, Tennessee 37831, USA
| | - Jonathan D Nickels
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. and Joint Institute for Neutron Sciences, Oak Ridge, Tennessee 37831, USA
| | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, Humboldtstr. 50/III, Graz, Austria. and BioTechMed-Graz, Graz, Austria
| | - John Katsaras
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. and Joint Institute for Neutron Sciences, Oak Ridge, Tennessee 37831, USA
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Gallová J, Klacsová M, Devínsky F, Balgavý P. Partial volumes of cholesterol and monounsaturated diacylphosphatidylcholines in mixed bilayers. Chem Phys Lipids 2015; 190:1-8. [DOI: 10.1016/j.chemphyslip.2015.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 05/20/2015] [Accepted: 06/15/2015] [Indexed: 10/23/2022]
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Kaspersen JD, Pedersen JN, Hansted JG, Nielsen SB, Sakthivel S, Wilhelm K, Nemashkalova EL, Permyakov SE, Permyakov EA, Pinto Oliveira CL, Morozova-Roche LA, Otzen DE, Pedersen JS. Generic structures of cytotoxic liprotides: nano-sized complexes with oleic acid cores and shells of disordered proteins. Chembiochem 2014; 15:2693-702. [PMID: 25403886 DOI: 10.1002/cbic.201402407] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Indexed: 11/05/2022]
Abstract
The cytotoxic complex formed between α-lactalbumin and oleic acid (OA) has inspired many studies on protein-fatty acid complexes, but structural insight remains sparse. After having used small-angle X-ray scattering (SAXS) to obtain structural information, we present a new, generic structural model of cytotoxic protein-oleic acid complexes, which we have termed liprotides (lipids and partially denatured proteins). Twelve liprotides formed from seven structurally unrelated proteins and prepared by different procedures all displayed core-shell structures, each with a micellar OA core and a shell consisting of flexible, partially unfolded protein, which stabilizes the OA micelle. The common structure explains similar effects exerted on cells by different liprotides and is consistent with a cargo off-loading of the OA into cell membranes.
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Affiliation(s)
- Jørn D Kaspersen
- Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C (Denmark)
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33
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Damas C, Carcenac Y, Abarbri M, Coudert R. Synthesis and physicochemical properties of unsaturated trifluoromethylated sodium carboxylates in aqueous media. J Colloid Interface Sci 2013; 395:119-26. [DOI: 10.1016/j.jcis.2012.11.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 11/27/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022]
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Hallinen KM, Tristram-Nagle S, Nagle JF. Volumetric stability of lipid bilayers. Phys Chem Chem Phys 2012; 14:15452-7. [PMID: 23069984 DOI: 10.1039/c2cp42595e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In agreement with recent reports, a commercial densimeter has yielded a gradual decrease in lipid molecular volume of DPPC multilamellar vesicle dispersions in the gel phase upon repeated thermal cycling between 10 °C and 50 °C. The considerable size of this decrease would have significant implications for the physical chemistry of biomembranes. In contrast, neutral buoyancy measurements performed with similar thermal cycling indicate no gradual change in lipid volume in the gel phase at 20 °C. Remixing the lipid in the densimeter shows that the apparent volume decrease is an artifact. We conclude that gel phase DPPC bilayers exist in a volumetrically stable phase.
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Affiliation(s)
- Kelsey M Hallinen
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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35
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Smith AK, Freed JH. Dynamics and ordering of lipid spin-labels along the coexistence curve of two membrane phases: An ESR study. Chem Phys Lipids 2012; 165:348-61. [DOI: 10.1016/j.chemphyslip.2012.02.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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36
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Volumetric characterization of ester- and ether-linked lipid bilayers by pressure perturbation calorimetry and densitometry. Colloids Surf B Biointerfaces 2012; 92:232-9. [DOI: 10.1016/j.colsurfb.2011.11.055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 11/25/2011] [Accepted: 11/28/2011] [Indexed: 11/17/2022]
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37
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Marsh D. Bilayer dimensions and hydration of glycolipids. Chem Phys Lipids 2012; 165:23-31. [DOI: 10.1016/j.chemphyslip.2011.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 09/28/2011] [Accepted: 10/12/2011] [Indexed: 11/30/2022]
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38
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Wadsäter M, Simonsen JB, Lauridsen T, Tveten EG, Naur P, Bjørnholm T, Wacklin H, Mortensen K, Arleth L, Feidenhans'l R, Cárdenas M. Aligning nanodiscs at the air-water interface, a neutron reflectivity study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:15065-15073. [PMID: 22047603 DOI: 10.1021/la203100n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Nanodiscs are self-assembled nanostructures composed of a belt protein and a small patch of lipid bilayer, which can solubilize membrane proteins in a lipid bilayer environment. We present a method for the alignment of a well-defined two-dimensional layer of nanodiscs at the air-water interface by careful design of an insoluble surfactant monolayer at the surface. We used neutron reflectivity to demonstrate the feasibility of this approach and to elucidate the structure of the nanodisc layer. The proof of concept is hereby presented with the use of nanodiscs composed of a mixture of two different lipid (DMPC and DMPG) types to obtain a net overall negative charge of the nanodiscs. We find that the nanodisc layer has a thickness or 40.9 ± 2.6 Å with a surface coverage of 66 ± 4%. This layer is located about 15 Å below a cationic surfactant layer at the air-water interface. The high level of organization within the nanodiscs layer is reflected by a low interfacial roughness (~4.5 Å) found. The use of the nanodisc as a biomimetic model of the cell membrane allows for studies of single membrane proteins isolated in a confined lipid environment. The 2D alignment of nanodiscs could therefore enable studies of high-density layers containing membrane proteins that, in contrast to membrane proteins reconstituted in a continuous lipid bilayer, remain isolated from influences of neighboring membrane proteins within the layer.
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Affiliation(s)
- Maria Wadsäter
- Nano-Science Center and Institute of Chemistry, Faculty of Life Sciences, University of Copenhagen, Copenhagen, Denmark.
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Marsh D. Pivotal surfaces in inverse hexagonal and cubic phases of phospholipids and glycolipids. Chem Phys Lipids 2011; 164:177-83. [DOI: 10.1016/j.chemphyslip.2010.12.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 12/21/2010] [Indexed: 11/29/2022]
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