1
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Mortara L, Mukhina T, Chaimovich H, Brezesinski G, van der Vegt NFA, Schneck E. Anion Competition at Positively Charged Surfactant Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:6949-6961. [PMID: 38502024 DOI: 10.1021/acs.langmuir.3c04003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Interactions of anions with hydrophobic surfaces of proteins and water-soluble polymers depend on the ability of the ions to shed their hydration shells. At positively charged surfactant monolayers, the interactions of anions are less well understood. Due to the interplay of electrostatic surface forces, hydration effects, and ion-ion interactions in the electrostatic double layer, a comprehensive microscopic picture remains elusive. Herein, we study the interactions of chloride, bromide, and a mixture of these two anions at the aqueous interface of dihexadecyldimethylammonium (DHDA+) and dioctadecyldimethylammonium (DODA+) cationic monolayers. Using molecular dynamics simulations and three surface-sensitive X-ray scattering techniques, we demonstrate that bromide interacts preferentially over chloride with both monolayers. The structure of the two monolayers and their interfacial electron density profiles obtained from the simulations quantitatively reproduce the experimental data. We observe that chloride and bromide form contact ion pairs with the quaternary ammonium groups on both monolayers. However, ion pairing with bromide leads to a greater reduction in the number of water molecules hydrating the anion, resulting in more energetically stable ion pairs. This leads to long-range (>3 nm) lateral correlations between bromide ions on the structured DODA+ monolayer. These observations indicate that ion hydration is the dominant factor determining the interfacial electrolyte structure.
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Affiliation(s)
- Laura Mortara
- Chemistry Institute, University of São Paulo, São Paulo, SP 05508-000, Brazil
- Physics Department, Technical University of Darmstadt, Darmstadt 64289, Germany
| | - Tetiana Mukhina
- Physics Department, Technical University of Darmstadt, Darmstadt 64289, Germany
| | - Hernan Chaimovich
- Chemistry Institute, University of São Paulo, São Paulo, SP 05508-000, Brazil
| | - Gerald Brezesinski
- Physics Department, Technical University of Darmstadt, Darmstadt 64289, Germany
| | | | - Emanuel Schneck
- Physics Department, Technical University of Darmstadt, Darmstadt 64289, Germany
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2
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Trevorah RM, Viljanen M, Viitaja T, Stubb H, Sevón J, Konovalov O, Jankowski M, Fontaine P, Hemmerle A, Raitanen JE, Ekholm FS, Svedström KJ. New Insights into the Molecular Structure of Tear Film Lipids Revealed by Surface X-ray Scattering. J Phys Chem Lett 2024; 15:316-322. [PMID: 38170161 PMCID: PMC10788950 DOI: 10.1021/acs.jpclett.3c02958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/12/2023] [Accepted: 12/28/2023] [Indexed: 01/05/2024]
Abstract
The tear film lipid layer (TFLL) is a unique biological membrane that serves a pivotal role in the maintenance of ocular surface health. Reaching an overarching understanding of the functional principle of the TFLL has been hampered by a lack of insights into the structural and functional roles played by individual lipid classes. To bridge this knowledge gap, we herein focus on studying films formed by principal lipid classes by surface scattering methods. Through grazing incidence X-ray diffraction and X-ray reflectivity studies, we reveal quantitative data about the lattice distances, molecular tilt angles, and mono/multilayer thickness and density profiles for central TFLL lipid classes under close to simulated physiological conditions. In addition, we discuss the correlation of the results to those obtained previously with the natural lipid composition of meibum.
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Affiliation(s)
- Ryan M. Trevorah
- Department
of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Mira Viljanen
- Department
of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tuomo Viitaja
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
- Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, FI-00290 Helsinki, Finland
| | - Henrik Stubb
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Julia Sevón
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Oleg Konovalov
- The
European Synchrotron Radiation Facility - ESRF, 71 Avenue des Martyrs, CS 40220, Grenoble Cedex 9 38043, France
| | - Maciej Jankowski
- The
European Synchrotron Radiation Facility - ESRF, 71 Avenue des Martyrs, CS 40220, Grenoble Cedex 9 38043, France
| | - Philippe Fontaine
- Synchrotron
SOLEIL, L’Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
| | - Arnaud Hemmerle
- Synchrotron
SOLEIL, L’Orme des Merisiers, Départementale 128, 91190 Saint-Aubin, France
| | - Jan-Erik Raitanen
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Filip S. Ekholm
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Kirsi J. Svedström
- Department
of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
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3
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Grava M, Ibrahim M, Sudarsan A, Pusterla J, Philipp J, Rädler JO, Schwierz N, Schneck E. Combining molecular dynamics simulations and x-ray scattering techniques for the accurate treatment of protonation degree and packing of ionizable lipids in monolayers. J Chem Phys 2023; 159:154706. [PMID: 37861119 DOI: 10.1063/5.0172552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023] Open
Abstract
The pH-dependent change in protonation of ionizable lipids is crucial for the success of lipid-based nanoparticles as mRNA delivery systems. Despite their widespread application in vaccines, the structural changes upon acidification are not well understood. Molecular dynamics simulations support structure prediction but require an a priori knowledge of the lipid packing and protonation degree. The presetting of the protonation degree is a challenging task in the case of ionizable lipids since it depends on pH and on the local lipid environment and often lacks experimental validation. Here, we introduce a methodology of combining all-atom molecular dynamics simulations with experimental total-reflection x-ray fluorescence and scattering measurements for the ionizable lipid Dlin-MC3-DMA (MC3) in POPC monolayers. This joint approach allows us to simultaneously determine the lipid packing and the protonation degree of MC3. The consistent parameterization is expected to be useful for further predictive modeling of the action of MC3-based lipid nanoparticles.
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Affiliation(s)
- Miriam Grava
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Mohd Ibrahim
- Institute of Physics, University of Augsburg, Augsburg, Germany
| | - Akhil Sudarsan
- Institute of Physics, University of Augsburg, Augsburg, Germany
| | - Julio Pusterla
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Julian Philipp
- Fakultät für Physik, Ludwig-Maximilians-Universität München (LMU), München, Germany
| | - Joachim O Rädler
- Fakultät für Physik, Ludwig-Maximilians-Universität München (LMU), München, Germany
| | - Nadine Schwierz
- Institute of Physics, University of Augsburg, Augsburg, Germany
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
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4
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Stefaniu C, Wölk C, Latza VM, Chumakov A, Brezesinski G, Schneck E. Cross-linking reactions in Langmuir monolayers of specially designed aminolipids - a toolbox for the customized production of amphiphilic nanosheets. NANOSCALE ADVANCES 2023; 5:4589-4597. [PMID: 37638167 PMCID: PMC10448339 DOI: 10.1039/d3na00244f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 08/09/2023] [Indexed: 08/29/2023]
Abstract
Synthetic amino lipids, already known as highly efficient gene therapy tool, are used in a novel way to create cross-linked stable one-molecule-thin films envisioned for future (bio)-materials applications. The films are prepared as Langmuir monolayers at the air/water interface and cross-linked 'in situ' via dynamic imine chemistry. The cross-linking process and the film characteristics are monitored by various surface-sensitive techniques such as grazing incidence X-ray diffraction, X-ray reflectivity, and infrared reflection-absorption spectroscopy. After transfer onto carbon grids, the cross-linked films are investigated by transmission and scanning electron microscopy. The obtained micrographs display mechanically self-supported nanosheets with area dimensions over several micrometers and, thus, an undeniable visual proof of successful cross-linking. The cross-linking process at the air/water interface allows to obtain Janus-faced sheets with a hydrophobic side characterized by aliphatic alkyl chains and a hydrophilic side characterized by nucleophilic groups like amines, hydroxyl groups and imine.
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Affiliation(s)
- Cristina Stefaniu
- Departments of Biomaterials and Biomolecular Systems, Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
| | - Christian Wölk
- Pharmaceutical Technology, Faculty of Medicine, University of Leipzig Eilenburger Str. 15a 04317 Leipzig Germany
| | - Victoria M Latza
- Departments of Biomaterials and Biomolecular Systems, Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
| | - Andrei Chumakov
- European Synchrotron Radiation Facility 71, avenue des Martyrs, CS 40220 38043 Grenoble Cedex 9 France
| | - Gerald Brezesinski
- Departments of Biomaterials and Biomolecular Systems, Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
- Department of Physics, TU Darmstadt Hochschulstr. 8 64289 Darmstadt Germany
| | - Emanuel Schneck
- Departments of Biomaterials and Biomolecular Systems, Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
- Department of Physics, TU Darmstadt Hochschulstr. 8 64289 Darmstadt Germany
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5
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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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6
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Poirier A, Le Griel P, Hoffmann I, Perez J, Pernot P, Fresnais J, Baccile N. Ca 2+ and Ag + orient low-molecular weight amphiphile self-assembly into "nano-fishnet" fibrillar hydrogels with unusual β-sheet-like raft domains. SOFT MATTER 2023; 19:378-393. [PMID: 36562421 DOI: 10.1039/d2sm01218a] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Low-molecular weight gelators (LMWGs) are small molecules (Mw < ∼1 kDa), which form self-assembled fibrillar network (SAFiN) hydrogels in water when triggered by an external stimulus. A great majority of SAFiN gels involve an entangled network of self-assembled fibers, in analogy to a polymer in a good solvent. In some rare cases, a combination of attractive van der Waals and repulsive electrostatic forces drives the formation of bundles with a suprafibrillar hexagonal order. In this work, an unexpected micelle-to-fiber transition is triggered by Ca2+ or Ag+ ions added to a micellar solution of a novel glycolipid surfactant, whereas salt-induced fibrillation is not common for surfactants. The resulting SAFiN, which forms a hydrogel above 0.5 wt%, has a "nano-fishnet" structure, characterized by a fibrous network of both entangled fibers and β-sheet-like rafts, generally observed for silk fibroin, actin hydrogels or mineral imogolite nanotubes, but not known for SAFiNs. The β-sheet-like raft domains are characterized by a combination of cryo-TEM and SAXS and seem to contribute to the stability of glycolipid gels. Furthermore, glycolipid is obtained by fermentation from natural resources (glucose, rapeseed oil), thus showing that naturally engineered compounds can have unprecedented properties, when compared to the wide range of chemically derived amphiphiles.
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Affiliation(s)
- Alexandre Poirier
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire de Chimie de la Matière Condensée de Paris, LCMCP, F-75005 Paris, France.
| | - Patrick Le Griel
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire de Chimie de la Matière Condensée de Paris, LCMCP, F-75005 Paris, France.
| | | | - Javier Perez
- Synchrotron Soleil, L'Orme des Merisiers, Saint-Aubin, BP48, 91192 Gif-sur-Yvette Cedex, France
| | - Petra Pernot
- ESRF - The European Synchrotron, CS40220, 38043 Grenoble, France
| | - Jérôme Fresnais
- Sorbonne Université, CNRS, Laboratoire de Physico-chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX - UMR 8234, F-75252, Paris Cedex 05, France
| | - Niki Baccile
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire de Chimie de la Matière Condensée de Paris, LCMCP, F-75005 Paris, France.
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7
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Poirier A, Le Griel P, Bizien T, Zinn T, Pernot P, Baccile N. Shear recovery and temperature stability of Ca 2+ and Ag + glycolipid fibrillar metallogels with unusual β-sheet-like domains. SOFT MATTER 2023; 19:366-377. [PMID: 36508178 DOI: 10.1039/d2sm00374k] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Low-molecular weight gelators (LMWGs) are small molecules (Mw < ∼1 kDa), which form self-assembled fibrillar network (SAFiN) hydrogels in water. A great majority of SAFiN gels are described by an entangled network of self-assembled fibers, in analogy to a polymer in a good solvent. Here, fibrillation of a biobased glycolipid bolaamphiphile is triggered by Ca2+ or Ag+ ions which are added to its diluted micellar phase. The resulting SAFiN, which forms a hydrogel above 0.5 wt%, has a "nano-fishnet" structure, characterized by a fibrous network of both entangled fibers and β-sheet-like rafts, generally observed for silk fibroin, actin hydrogels or mineral imogolite nanotubes, but generally not known for SAFiN. This work focuses on the strength of the SAFIN gels, their fast recovery after applying a mechanical stimulus (strain) and their unusual resistance to temperature, studied by coupling rheology to small angle X-ray scattering (rheo-SAXS) using synchrotron radiation. The Ca2+-based hydrogel maintains its properties up to 55 °C, while the Ag+-based gel shows a constant elastic modulus up to 70 °C, without the appearance of any gel-to-sol transition temperature. Furthermore, the glycolipid is obtained by fermentation from natural resources (glucose and rapeseed oil), thus showing that naturally engineered compounds can have unprecedented properties, when compared to the wide range of chemically derived amphiphiles.
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Affiliation(s)
- Alexandre Poirier
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire de Chimie de la Matière Condensée de Paris, LCMCP, F-75005 Paris, France.
| | - Patrick Le Griel
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire de Chimie de la Matière Condensée de Paris, LCMCP, F-75005 Paris, France.
| | - Thomas Bizien
- Synchrotron Soleil, L'Orme des Merisiers, Saint-Aubin, BP48, 91192 Gif-sur-Yvette Cedex, France
| | - Thomas Zinn
- ESRF - The European Synchrotron, CS40220, 38043 Grenoble, France
| | - Petra Pernot
- ESRF - The European Synchrotron, CS40220, 38043 Grenoble, France
| | - Niki Baccile
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire de Chimie de la Matière Condensée de Paris, LCMCP, F-75005 Paris, France.
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8
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Langmuir monolayers as models of the lipid matrix of cyanobacterial thylakoid membranes. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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9
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Pusterla J, Scoppola E, Appel C, Mukhina T, Shen C, Brezesinski G, Schneck E. Characterization of lipid bilayers adsorbed to functionalized air/water interfaces. NANOSCALE 2022; 14:15048-15059. [PMID: 36200471 DOI: 10.1039/d2nr03334h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Lipid bilayers immobilized in planar geometries, such as solid-supported or "floating" bilayers, have enabled detailed studies of biological membranes with numerous experimental techniques, notably X-ray and neutron reflectometry. However, the presence of a solid support also has disadvantages as it complicates the use of spectroscopic techniques as well as surface rheological measurements that would require surface deformations. Here, in order to overcome these limitations, we investigate lipid bilayers adsorbed to inherently soft and experimentally well accessible air/water interfaces that are functionalized with Langmuir monolayers of amphiphiles. The bilayers are characterized with ellipsometry, X-ray scattering, and X-ray fluorescence. Grazing-incidence X-ray diffraction reveals that lipid bilayers in a chain-ordered state can have significantly different structural features than regular Langmuir monolayers of the same composition. Our results suggest that bilayers at air/water interfaces may be well suited for fundamental studies in the field of membrane biophysics.
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Affiliation(s)
- Julio Pusterla
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Ernesto Scoppola
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Christian Appel
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Tetiana Mukhina
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Chen Shen
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Gerald Brezesinski
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
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10
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Mukhina T, Richter L, Vollhardt D, Brezesinski G, Schneck E. The Complete Phase Diagram of Monolayers of Enantiomeric N-Stearoyl-threonine Mixtures with Preferred Heterochiral Interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:12521-12529. [PMID: 36209408 PMCID: PMC9583611 DOI: 10.1021/acs.langmuir.2c01936] [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: 07/21/2022] [Revised: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Langmuir monolayers of chiral amphiphiles are well-controlled model systems for the investigation of phenomena related to stereochemistry. Here, we have investigated mixed monolayers of one pair of enantiomers (l and d) of the amino-acid-based amphiphile N-stearoyl-threonine. The monolayer characteristics were studied by pressure-area isotherm measurements and grazing incidence X-ray diffraction (GIXD) over a wide range of mixing ratios defined by the d-enantiomer mole fraction xD. While the isotherms provide insights into thermodynamical aspects, such as transition pressure, compression/decompression hysteresis, and preferential homo- and heterochiral interactions, GIXD reveals the molecular structural arrangements on the Ångström scale. Dominant heterochiral interactions in the racemic mixture lead to compound formation and the appearance of a nonchiral rectangular lattice, although the pure enantiomers form a chiral oblique lattice. Miscibility was found to be limited to mixtures with 0.27 ≲ xD ≲ 0.73, as well as to both outer edges (xD ≲ 0.08 and xD ≳ 0.92). Beyond this range, coexistence of oblique and rectangular lattices occurs, as is clearly seen in the GIXD patterns. Based on the results, a complete phase diagram with two eutectic points at xD ≈ 0.25 and xD ≈ 0.75 is proposed. Moreover, N-stearoyl-threonine was found to have a strong tendency to form a hydrogen-bonding network between the headgroups, which promotes superlattice formation.
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Affiliation(s)
- Tetiana Mukhina
- Institute
for Condensed Matter Physics, Technical
University of Darmstadt, Hochschulstraße 8, 64289Darmstadt, Germany
| | - Lars Richter
- Institute
for Condensed Matter Physics, Technical
University of Darmstadt, Hochschulstraße 8, 64289Darmstadt, Germany
| | - Dieter Vollhardt
- Max-Planck
Institute for Polymer Research, Ackermannweg 10, D-55128Mainz, Germany
| | - Gerald Brezesinski
- Institute
for Condensed Matter Physics, Technical
University of Darmstadt, Hochschulstraße 8, 64289Darmstadt, Germany
| | - Emanuel Schneck
- Institute
for Condensed Matter Physics, Technical
University of Darmstadt, Hochschulstraße 8, 64289Darmstadt, Germany
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11
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Sturm M, Gutowski O, Brezesinski G. The Effect of pH on the Structure and Lateral Organization of Cardiolipin in Langmuir Monolayers. Chemphyschem 2022; 23:e202200218. [PMID: 35920819 DOI: 10.1002/cphc.202200218] [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: 03/31/2022] [Revised: 06/17/2022] [Indexed: 01/07/2023]
Abstract
Cardiolipin (CL) is a unique phospholipid featuring a dimeric structure. With its four alkyl chains, it has a large hydrophobic region and the charged hydrophilic head group is relatively small. Biological membranes exhibit CL exclusively in the inner bacterial and mitochondrial membranes. Alteration of CL packing can lead to structural changes and membrane instabilities. One environmental influence is the change in pH. Since the acidic properties of the phosphate head groups remain still controversial in literature, this work focusses on the influence of pH on the ionization degree of CL. For the analyses, surface pressure (π) - molecular area (A) isotherm experiments were combined with total reflection X-ray fluorescence (TRXF) and grazing incidence X-ray diffraction (GIXD). Continuous ionization with a high CL packing density was observed in the monolayer over a wide pH range. No individual pKa values can be assigned to the two phosphate groups, but mutual influence is observed.
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Affiliation(s)
- Marina Sturm
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Olof Gutowski
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Gerald Brezesinski
- Institute of Applied Dermatopharmacy, Martin Luther University Halle-Wittenberg, Weinbergweg 23, 06120, Halle (Saale), Germany
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12
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Mukhina T, Pabst G, Ruysschaert JM, Brezesinski G, Schneck E. pH-Dependent physicochemical properties of ornithine lipid in mono- and bilayers. Phys Chem Chem Phys 2022; 24:22778-22791. [PMID: 36111816 DOI: 10.1039/d2cp01045c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In certain bacteria, phosphatidylethanolamine lipids (PEL) get largely replaced by phosphate-free ornithine lipids (OL) under conditions of phosphate starvation. It has so far been unknown how much these two lipid types deviate in their physicochemical properties, and how strongly bacteria thus have to adapt in order to compensate for the difference. Here, we use differential scanning calorimetry, X-ray scattering, and X-ray fluorescence to investigate the properties of OL with saturated C14 alkyl chains in mono- and bilayers. OL is found to have a greater tendency than chain-analogous PEL to form ordered structures and, in contrast to PEL, even a molecular superlattice based on a hydrogen bonding network between the headgroups. This superlattice is virtually electrically uncharged and persists over a wide pH range. Our results indicate that OL and PEL behave very differently in ordered single-component membranes but may behave more similarly in fluid multicomponent membranes.
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Affiliation(s)
- Tetiana Mukhina
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrase 8, 64289 Darmstadt, Germany.
| | - Georg Pabst
- Insitute of Molecular Biosciences, University of Graz, Universitätsplatz 3, 8010, Graz, Austria
| | - Jean-Marie Ruysschaert
- Laboratoire de Structure et Fonction des Membranes Biologiques, Université Libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Gerald Brezesinski
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrase 8, 64289 Darmstadt, Germany.
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrase 8, 64289 Darmstadt, Germany.
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13
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Mukhina T, Brezesinski G, Schneck E. Phase Behavior and Miscibility in Two-Component Glycolipid Monolayers. J Phys Chem B 2022; 126:6464-6471. [PMID: 35976765 DOI: 10.1021/acs.jpcb.2c05016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Glycolipids are known to be involved in the formation of ordered functional domains in biological membranes. Since the structural characterization of such domains is difficult, most studies have so far dealt with lipid mixtures containing only one glycolipid component at a time, although biological membranes usually contain several glycolipid species, which can result in more complex structures and phase behavior. Here, we combine classical isotherm measurements with surface-sensitive grazing-incidence X-ray diffraction to investigate the phase behavior and miscibility in Langmuir monolayers of binary glycolipid mixtures. We find that the phase behavior has a subtle dependence on the saccharide headgroup chemistry. For compatible chemistries, molecular superlattice structures formed by one of the glycolipid species are conserved and can host foreign glycolipids up to a defined stoichiometry. In contrast, for sterically incompatible saccharide chemistries, the superlattice is lost even if both species are able to form such structures in their pure forms. Our results suggest that related phenomena may play important roles also in biological contexts.
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Affiliation(s)
- Tetiana Mukhina
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Gerald Brezesinski
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
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14
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Perczyk P, Broniatowski M. Membrane composition and successful bioaugmentation. Studies of the interactions of model thylakoid and plasma cyanobacterial and bacterial membranes with fungal membrane-lytic enzyme Lecitase ultra. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183888. [PMID: 35189110 DOI: 10.1016/j.bbamem.2022.183888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/01/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Cyanobacterial/bacterial consortia are frequently inoculated to soils to increase the soil fertility and to accelerate the biodegradation of organic pollutants. Moreover, such consortia can also be successfully applied in landfills especially for the biodegradation of plastic wastes. However, the bioaugmentation techniques turn out frequently inefficient due to the competition of the indigenous microorganisms attacking directly these inoculated or secreting to their surroundings cell wall and membrane-lytic enzymes. It can be hypothesized that the resistance of the microbial membrane to the enzymatic degradation is correlated with its lipid composition. To verify this hypothesis glycolipid and phospholipid Langmuir monolayers were applied as models of thylakoid and plasma cyanobacterial and bacterial membranes. Hybrid fungal enzyme Lecitase ultra joining the activity of lipase and phospholipase A1 was applied as the model of fungal membrane-lytic enzyme. It turned out that anionic thylakoid lipids sulfoquinovosyldiacylglycerol and phosphatidylglycerols were the main targets of Lecitase ultra in the model multicomponent thylakoid membranes. The resistance of the model plasma bacterial membranes to enzymatic degradation depended significantly to their composition. The resistance increased generally when the unsaturated lipids were exchanged to their saturated counterparts. However, most resistant turned out the membranes composed of unsaturated phosphatidylamine and saturated anionic phospholipids.
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Affiliation(s)
- Paulina Perczyk
- Department of Environmental Chemistry, Faculty of Chemistry, The Jagiellonian University in Krakow, Gronostajowa 2, 30-387 Kraków, Poland
| | - Marcin Broniatowski
- Department of Environmental Chemistry, Faculty of Chemistry, The Jagiellonian University in Krakow, Gronostajowa 2, 30-387 Kraków, Poland..
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15
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Pusterla JM, Cannas SA, Schneck E, Oliveira RG. Purified myelin lipids display a critical mixing point at low surface pressure. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183874. [PMID: 35120896 DOI: 10.1016/j.bbamem.2022.183874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Lipids extracted from Purified Myelin Membranes (LPMM) were spread as monomolecular films at the air/aqueous interface. The films were visualized by Brewster Angle Microscopy (BAM) at different lateral pressures (π) and ionic environments. Coexistence of Liquid-Expanded (LE) and cholesterol-enriched (CE) rounded domains persisted up to π ≈ 5 mN/m but the monolayers became homogeneous at higher surface pressures. Before mixing, the domains distorted to non-rounded domains. We experimentally measured the line tension (λ) for the lipid monolayers at the domain borders by a shape relaxation technique using non-homogeneous electric fields. Regardless of the subphase conditions, the obtained line tensions are of the order of pN and tended to decrease as lateral pressure increased toward the mixing point. From the mean square displacement of nested trapped domains, we also calculated the dipole density difference between phases (μ). A non-linear drop was detected in this parameter as the mixing point is approached. Here we quantitively evaluated the π-dependance of both parameters with proper power laws in the vicinity of the critical mixing surface pressure, and the exponents showed to be consistent with a critical phenomenon in the two-dimensional Ising universality class. This idea of bidimensionality was found to be compatible only for simplified lipidic systems, while for whole myelin monolayers, that means including proteins, no critical mixing point was detected. Finally, the line tension values were related with the thickness differences between phases (Δt) near the critical point.
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Affiliation(s)
- Julio M Pusterla
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC)-Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina; Institut für Physik Kondensierter Materie, Technische Universität Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Sergio A Cannas
- Instituto de Física Enrique Gaviola (IFEG-CONICET), Facultad de Matemática Astronomía Física y Computación, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina.
| | - Emanuel Schneck
- Institut für Physik Kondensierter Materie, Technische Universität Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Rafael G Oliveira
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC)-Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina.
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16
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Paracini N, Schneck E, Imberty A, Micciulla S. Lipopolysaccharides at Solid and Liquid Interfaces: Models for Biophysical Studies of the Gram-negative Bacterial Outer Membrane. Adv Colloid Interface Sci 2022; 301:102603. [PMID: 35093846 DOI: 10.1016/j.cis.2022.102603] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 11/18/2022]
Abstract
Lipopolysaccharides (LPSs) are a constitutive element of the cell envelope of Gram-negative bacteria, representing the main lipid in the external leaflet of their outer membrane (OM) lipid bilayer. These unique surface-exposed glycolipids play a central role in the interactions of Gram-negative organisms with their surrounding environment and represent a key element for protection against antimicrobials and the development of antibiotic resistance. The biophysical investigation of a wide range of different types of in vitro model membranes containing reconstituted LPS has revealed functional and structural properties of these peculiar membrane lipids, providing molecular-level details of their interaction with antimicrobial compounds. LPS assemblies reconstituted at interfaces represent a versatile tool to study the properties of the Gram-negative OM by exploiting several surface-sensitive techniques, in particular X-ray and neutron scattering, which can probe the structure of thin films with sub-nanometer resolution. This review provides an overview of different approaches employed to investigate structural and biophysical properties of LPS, focusing on studies on Langmuir monolayers of LPS at the air/liquid interface and a range of supported LPS-containing model membranes reconstituted at solid/liquid interfaces.
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Affiliation(s)
| | - Emanuel Schneck
- Physics Departent, Technische Universität Darmstadt, Darmstadt, Germany
| | - Anne Imberty
- Université Grenoble Alpes, CNRS, CERMAV, Grenoble, France
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17
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Mukhina T, Brezesinski G, Shen C, Schneck E. Phase behavior and miscibility in lipid monolayers containing glycolipids. J Colloid Interface Sci 2022; 615:786-796. [PMID: 35176545 DOI: 10.1016/j.jcis.2022.01.146] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/19/2022] [Accepted: 01/23/2022] [Indexed: 01/02/2023]
Abstract
HYPOTHESIS Glycolipids in biological membranes are ubiquitous and believed to be involved in the formation of ordered functional domains. However, our current knowledge about such glycolipid-enriched domains is limited because they are inherently difficult to characterize. EXPERIMENTS We use grazing-incidence X-ray diffraction, isotherm measurements, and Brewster angle microscopy to investigate the phase behavior and miscibility in Langmuir lipid monolayers containing glycolipids. FINDINGS Glycolipid-enriched domains give rise to distinct diffraction patterns that allow for a systematic structural investigation and reveal a rich phenomenology, ranging from near-complete demixing to the formation of mixed domains with unique features. The phase behavior is governed by the headgroup chemistry and by the length and saturation of the tails.
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Affiliation(s)
- Tetiana Mukhina
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany.
| | - Gerald Brezesinski
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany.
| | - Chen Shen
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany.
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18
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Liao YF, Zhou MH, Zhang Y, Peng YY, Jian JX, Lu F, Tong QX. Facile synthesis and marked pH-responsive behavior of novel foaming agents based on amide- and ester-linked morpholine fluorosurfactants. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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19
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Malik A, Seeberger PH, Brezesinski G, Varón Silva D. Zwitterionic Character and Lipid Composition Determine the Behaviour of Glycosylphosphatidylinositol Fragments in Monolayers. Chemphyschem 2021; 22:757-763. [PMID: 33586851 PMCID: PMC8251720 DOI: 10.1002/cphc.202100002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/12/2021] [Indexed: 11/20/2022]
Abstract
Glycosylphosphatidylinositols (GPIs) are complex glycolipids found in free form or anchoring proteins to the outer leaflet of the cell membrane in eukaryotes. GPIs have been associated with the formation of lipid rafts and protein sorting on membranes. The presence of a conserved glycan core with cell-specific modifications together with lipid remodelling during biosynthesis suggest that the properties of the glycolipids are being fine-tuned. We synthesized a series of GPI fragments and evaluated the interactions and arrangement of these glycolipids in monolayers as a 2-D membrane model. GIXD and IRRAS analyses showed the need of N-acetylglucosamine deacetylation for the formation of hydrogen bonds to obtain highly structured domains in the monolayers and an effect of the unsaturated lipids in formation and localization of the glycolipids within or between membrane microdomains. These results contribute to understand the role of these glycolipids and their modifications in the organization of membranes.
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Affiliation(s)
- Ankita Malik
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Muehlenberg 114476PotsdamGermany
- Department of Chemistry and BiochemistryFreie Universität BerlinArnimallee 2214195BerlinGermany
| | - Peter H. Seeberger
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Muehlenberg 114476PotsdamGermany
- Department of Chemistry and BiochemistryFreie Universität BerlinArnimallee 2214195BerlinGermany
| | - Gerald Brezesinski
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Muehlenberg 114476PotsdamGermany
| | - Daniel Varón Silva
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Muehlenberg 114476PotsdamGermany
- Department of Chemistry and BiochemistryFreie Universität BerlinArnimallee 2214195BerlinGermany
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20
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Kanduč M, Schneck E, Stubenrauch C. Intersurfactant H-bonds between head groups of n-dodecyl-β-d-maltoside at the air-water interface. J Colloid Interface Sci 2021; 586:588-595. [DOI: 10.1016/j.jcis.2020.10.125] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 10/23/2022]
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21
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Membrane Adhesion via Glycolipids Occurs for Abundant Saccharide Chemistries. Biophys J 2020; 118:1602-1611. [PMID: 32097623 DOI: 10.1016/j.bpj.2020.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/29/2020] [Accepted: 02/05/2020] [Indexed: 01/03/2023] Open
Abstract
Membrane-bound oligosaccharides with specific chemistries are known to promote tight adhesion between adjacent membranes via the formation of weak saccharide bonds. However, in the literature, one can find scattered evidence that other, more abundant saccharide chemistries exhibit similar behavior. Here, the influence of various glycolipids on the interaction between adjacent membranes is systematically investigated with the help of small- and wide-angle x-ray scattering and complementary neutron diffraction experiments. Added electrostatic repulsion between the membrane surfaces is used to identify the formation of saccharide bonds and to challenge their stability against tensile stress. Some of the saccharide headgroup types investigated are able to bind adjacent membranes together, but this ability has no significant influence on the membrane bending rigidity. Our results indicate that glycolipid-mediated membrane adhesion is a highly abundant phenomenon and therefore potentially of great biological relevance.
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22
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Pusterla JM, Schneck E, Oliveira RG. Phase Diagram of Purified CNS Myelin Reveals Continuous Transformation between Expanded and Compacted Lamellar States. Cells 2020; 9:cells9030670. [PMID: 32164218 PMCID: PMC7140690 DOI: 10.3390/cells9030670] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/27/2020] [Accepted: 03/07/2020] [Indexed: 11/30/2022] Open
Abstract
Purified myelin membranes (PMMs) are the starting material for biochemical studies, from individual components up to the isolation of detergent-resistant membrane (DRM) fractions or detergent-insoluble glycosphingolipid (DIG) fractions, which are commonly believed to resemble physiological lipid rafts. The normal DIG isolation protocol involves the extraction of lipids under moderate cooling. The isolation of PMMs also involves the cooling of myelin as well as exposure to low ionic strength (IS). Here, we addressed the combined influence of cooling and IS on the structure of PMMs. The phase behaviour was investigated by small angle X-ray diffraction. Analysis of the diffraction peaks revealed the lamellar periodicity (d), the number of periodically correlated bilayers (N), and the relatives fractions of each phase. Departure from physiological conditions induced a phase separation in myelin. The effect of monovalent and divalent ions was also compared at equivalent IS, showing a differential effect, and phase diagrams for both ion types were established—Ca2+ induced the well-known over-compacted phase, but additionally we also found an expanded phase at low IS. Na+ promoted phase separation, and also induced over-compaction at sufficiently high IS. Finally, exploring the whole phase diagram, we found evidence for the direct isothermal transformation from the expanded to the compacted phase, suggesting that both phases could in fact originate from the identical primary lateral phase separation, whereas the apparent difference lies in the inter-bilayer interaction that is modulated by the ionic milieu.
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Affiliation(s)
- Julio M. Pusterla
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC)-Departamento de Química Biológica Dr. Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina;
- Department of Physics, Institute of Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany;
| | - Emanuel Schneck
- Department of Physics, Institute of Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany;
| | - Rafael G. Oliveira
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC)-Departamento de Química Biológica Dr. Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina;
- Correspondence: ; Tel.: +54-351-5353855-3443
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23
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Brezesinski G, Calow ADJ, Pereira CL, Seeberger PH. Thermodynamic and Structural Behavior of α-Galactosylceramide and C6-Functionalized α-GalCer in 2D Layers at the Air-Liquid Interface. Chembiochem 2020; 21:241-247. [PMID: 31544285 PMCID: PMC7004034 DOI: 10.1002/cbic.201900491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Indexed: 12/12/2022]
Abstract
α-Galactosylceramide (α-GalCer; KRN7000) is a ligand for the glycoprotein CD1d that presents lipid antigens to natural killer T cells. Therefore, KRN7000 as well as some modified versions thereof have been widely investigated as part of novel immunotherapies. To examine the impact of structural modification, we investigated KRN7000 and C6-modified KRN7000 at the air-liquid interface using monolayer isotherms, BAM, IRRAS, GIXD, and TRXF. The amino group has no influence on the highly ordered sub-gel structures found at lateral pressures relevant for biological membranes. Neither lateral compression nor the protonation state of the amino group has a measurable effect on the lattice structure, which is defined by strong and rigid intermolecular hydrogen bonds. However, the first-order phase transition found for the C6-functionalized α-GalCer is connected with an extraordinary surface-inhibited nucleation. Our study demonstrates that KRN7000 can be functionalized at C6 without significantly changing the structural properties.
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Affiliation(s)
- Gerald Brezesinski
- Max Planck Institute of Colloids and InterfacesBiomolecular Systems DepartmentAm Mühlenberg 114476PotsdamGermany
| | - Adam D. J. Calow
- Max Planck Institute of Colloids and InterfacesBiomolecular Systems DepartmentAm Mühlenberg 114476PotsdamGermany
| | - Claney L. Pereira
- Max Planck Institute of Colloids and InterfacesBiomolecular Systems DepartmentAm Mühlenberg 114476PotsdamGermany
| | - Peter H. Seeberger
- Max Planck Institute of Colloids and InterfacesBiomolecular Systems DepartmentAm Mühlenberg 114476PotsdamGermany
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24
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Stefaniu C, Wölk C, Brezesinski G, Schneck E. Relationship between structure and molecular interactions in monolayers of specially designed aminolipids. NANOSCALE ADVANCES 2019; 1:3529-3536. [PMID: 36133531 PMCID: PMC9418614 DOI: 10.1039/c9na00355j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 07/23/2019] [Indexed: 05/05/2023]
Abstract
Artificial cationic lipids are already recognized as highly efficient gene therapy tools. Here, we focus on another potential use of aminolipids, in their electrically-uncharged state, for the formation of covalently cross-linked, one-molecule-thin films at interfaces. Such films are envisioned for future (bio-)materials applications. To this end, Langmuir monolayers of structurally different aminolipids are comprehensively characterized with the help of highly sensitive surface characterization techniques. Pressure-area isotherms, Brewster angle microscopy, grazing-incidence X-ray diffraction and infrared reflection-absorption spectrometry experiments provide a detailed, comparative molecular picture of the formed monolayers. This physico-chemical study highlights the relationship between chemical structures and intermolecular interactions, which can serve as a basis for the rational design of cross-linked thin films with precisely controlled properties.
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Affiliation(s)
- Cristina Stefaniu
- Departments of Biomaterials and Biomolecular Systems, Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
| | - Christian Wölk
- Institute of Pharmacy, Research Group Biochemical Pharmacy, Martin-Luther-University Wolfgang-Langenbeck-Strasse 4 06120 Halle (Saale) Germany
| | - Gerald Brezesinski
- Departments of Biomaterials and Biomolecular Systems, Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
| | - Emanuel Schneck
- Departments of Biomaterials and Biomolecular Systems, Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
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25
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Brezesinski G, Schneck E. Investigating Ions at Amphiphilic Monolayers with X-ray Fluorescence. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8531-8542. [PMID: 30835476 PMCID: PMC6727669 DOI: 10.1021/acs.langmuir.9b00191] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 03/04/2019] [Indexed: 06/09/2023]
Abstract
Amphiphilic monolayers formed at the soft air/liquid interface are easy-to-handle and versatile model systems for material and life sciences. Helmuth Möhwald was one of the pioneers in this field. Over the last few decades, total-reflection X-ray fluorescence (TRXF) has become an important analytical tool for the investigation of monolayer interactions with ions. Here, the theoretical background of TRXF is described, and practical aspects are discussed. The experimentally determined fluorescence intensity from the adsorbed ions can be interpreted quantitatively either by a calibration procedure utilizing monolayers with known charge density or by calibration with respect to the bare aqueous surface. Both calibration approaches yield quantitatively consistent results within <10% accuracy. Some examples demonstrating the power of TRXF for the study of ion adsorption to charged and noncharged monolayers as well as for the characterization of the physicochemical properties of novel cationic lipids used for improved gene delivery are given.
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Affiliation(s)
- Gerald Brezesinski
- Max Planck Institute of
Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Emanuel Schneck
- Max Planck Institute of
Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
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