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Shih KC, Leriche G, Liu CH, He J, John VT, Fang J, Barker JG, Nagao M, Yang L, Yang J, Nieh MP. Antivesiculation and Complete Unbinding of Tail-Tethered Lipids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1688-1697. [PMID: 38186288 DOI: 10.1021/acs.langmuir.3c02663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
We report the effect of tail-tethering on vesiculation and complete unbinding of bilayered membranes. Amphiphilic molecules of a bolalipid, resembling the tail-tethered molecular structure of archaeal lipids, with two identical zwitterionic phosphatidylcholine headgroups self-assemble into a large flat lamellar membrane, in contrast to the multilamellar vesicles (MLVs) observed in its counterpart, monopolar nontethered zwitterionic lipids. The antivesiculation is confirmed by small-angle X-ray scattering (SAXS) and cryogenic transmission electron microscopy (cyro-TEM). With the net charge of zero and higher bending rigidity of the membrane (confirmed by neutron spin echo (NSE) spectroscopy), the current membrane theory would predict that membranes should stack with each other (aka "bind") due to dominant van der Waals attraction, while the outcome of the nonstacking ("unbinding") membrane suggests that the theory needs to include entropic contribution for the nonvesicular structures. This report pioneers an understanding of how the tail-tethering of amphiphiles affects the structure, enabling better control over the final nanoscale morphology.
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Affiliation(s)
| | - Geoffray Leriche
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | | | - Jibao He
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Vijay T John
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | | | - John G Barker
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Michihiro Nagao
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States
| | - Lin Yang
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Jerry Yang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
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2
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Adsorption behavior and mechanism analysis of siloxane thickener for CO2 fracturing fluid on shallow shale soil. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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3
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Long chain ceramides raise the main phase transition of monounsaturated phospholipids to physiological temperature. Sci Rep 2022; 12:20803. [PMID: 36460753 PMCID: PMC9718810 DOI: 10.1038/s41598-022-25330-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022] Open
Abstract
Little is known about the molecular mechanisms of ceramide-mediated cellular signaling. We examined the effects of palmitoyl ceramide (C16-ceramide) and stearoyl ceramide (C18-ceramide) on the phase behavior of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) using differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS, WAXS). As previously published, the presence of ceramides increased the lamellar gel-to-lamellar liquid crystalline (Lβ-Lα) phase transition temperature of POPC and POPE and decreased the Lα-to-inverted hexagonal (Lα-HII) phase transition temperature of POPE. Interestingly, despite an ~ 30° difference in the main phase transition temperatures of POPC and POPE, the Lβ-Lα phase transition temperatures were very close between POPC/C18-ceramide and POPE/C18-ceramide and were near physiological temperature. A comparison of the results of C16-ceramide in published and our own results with those of C18-ceramide indicates that increase of the carbon chain length of ceramide from 16 to 18 and/or the small difference of ceramide content in the membrane dramatically change the phase transition temperature of POPC and POPE to near physiological temperature. Our results support the idea that ceramide signaling is mediated by the alteration of lipid phase-dependent partitioning of signaling proteins.
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Müller WA, Sarkis JR, Marczak LDF, Muniz AR. Molecular dynamics insights on temperature and pressure effects on electroporation. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:184049. [PMID: 36113558 DOI: 10.1016/j.bbamem.2022.184049] [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: 06/22/2022] [Revised: 09/02/2022] [Accepted: 09/08/2022] [Indexed: 06/15/2023]
Abstract
Electroporation is a cell-level phenomenon caused by an ionic imbalance in the membrane, being of great relevance in various fields of knowledge. A dependence of the pore formation kinetics on the environmental conditions (temperature and pressure) of the cell membrane has already been reported, but further clarification regarding how these variables affect the pore formation/resealing dynamics and the transport of molecules through the membrane is still lacking. The objective of the present study was to investigate the temperature (288-348 K) and pressure (1-5000 atm) effects on the electroporation kinetics using coarse-grained molecular dynamics simulations. Results shown that the time for pore formation and resealing increased with pressure and decreased with temperature, whereas the maximum pore radius increased with temperature and decreased with pressure. This behavior influenced the ion migration through the bilayer, and the higher ionic mobility was obtained in the 288 K/1000 atm simulations, i.e., a combination of low temperature and (not excessively) high pressure. These results were used to discuss some experimental observations regarding the extraction of intracellular compounds applying this technique. This study contributes to a better understanding of electroporation under different thermodynamic conditions and to an optimal selection of processing parameters in practical applications which exploit this phenomenon.
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Affiliation(s)
- Wagner Augusto Müller
- Universidade Federal do Rio Grande do Sul (UFRGS), Department of Chemical Engineering, Porto Alegre, RS, Brazil
| | - Júlia Ribeiro Sarkis
- Universidade Federal do Rio Grande do Sul (UFRGS), Department of Chemical Engineering, Porto Alegre, RS, Brazil
| | | | - André Rodrigues Muniz
- Universidade Federal do Rio Grande do Sul (UFRGS), Department of Chemical Engineering, Porto Alegre, RS, Brazil.
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5
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Self-assembly of supported lipid multi-bilayers investigated by time-resolved X-ray diffraction. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183437. [PMID: 32783887 DOI: 10.1016/j.bbamem.2020.183437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/30/2020] [Accepted: 07/30/2020] [Indexed: 11/23/2022]
Abstract
Supported lipid multi-bilayers or bilayer stacks are an important model membrane system, particularly suitable for surface-sensitive characterization methods like X-ray and neutron diffraction. Spreading organic solution (sOS) is one of the most widely used protocols for the preparation of lipid multi-bilayers. Despite its great popularity, the self-assembly mechanism of the bilayers is not yet fully elucidated, limiting further improvements of this protocol. In order to solve this problem, we investigated the formation process of lipid bilayers in the sOS protocol, using in-situ time-resolved X-ray diffraction, complemented by X-ray reflectivity and molecular dynamics simulation. Results reveal a simultaneous self-assembly scheme for both cholesterol-free and cholesterol-containing bilayers, with one bilayer phase forming at the surface and the other forming in the solution. The solution phase gradually transforms into the surface phase, yielding clean single phase in the end.
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6
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Sanver D, Sadeghpour A, Rappolt M, Di Meo F, Trouillas P. Structure and Dynamics of Dioleoyl-Phosphatidylcholine Bilayers under the Influence of Quercetin and Rutin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:11776-11786. [PMID: 32911935 DOI: 10.1021/acs.langmuir.0c01484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Quercetin and rutin, two widely studied flavonoids with applications foreseen in the sectors of pharmaceutical and cosmetic industries, have been chosen as model compounds for a detailed structural and dynamical investigation onto their influence on fluid lipid bilayers. Combining global small angle X-ray scattering analysis with molecular dynamics, various changes in the properties of dioleoyl-phosphatidylcholine (DOPC) bilayers have been determined. The solubility of quercetin in DOPC membranes is assured up to 12 mol %, whereas rutin, with additional glucose and rhamnose groups, are fully soluble only up to 6 mol %. Both flavonoids induce an increase in membrane undulations and thin the bilayers slightly (<1 Å) in a concentration dependent manner, wherein quercetin shows a stronger effect. Concomitantly, in the order of 2-4%, the adjacent bilayer distance increases with the flavonoid's concentration. Partial molecular areas of quercetin and rutin are determined to be 26 and 51 Å2, respectively. Simulated averaged areas per molecule confirm these estimates. A 60° tilted orientation of quercetin is observed with respect to the bilayer normal, whereas the flavonoid moiety of rutin is oriented more perpendicular (α-angle 30°) to the membrane surface. Both flavonoid moieties are located at a depth of 12 and 16 Å for quercetin and rutin, respectively, while their anionic forms display a location closer to the polar interface. Finally, at both simulated concentrations (1.5 and 12 mol %), DOPC-rutin systems induce a stronger packing of the pure DOPC lipid bilayer, mainly due to stronger attractive electrostatic interactions in the polar lipid head region.
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Affiliation(s)
- Didem Sanver
- Faculty of Engineering and Architecture, Department of Food Engineering, Necmettin Erbakan University, Konya 42050, Turkey
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, U.K
| | - Amin Sadeghpour
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, U.K
- Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Allschwil 4123, Switzerland
| | - Michael Rappolt
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, U.K
| | - Florent Di Meo
- INSERM U1248 IPPRITT, University of Limoges, 2 rue du Prof. Descottes, Limoges 87000, France
| | - Patrick Trouillas
- INSERM U1248 IPPRITT, University of Limoges, 2 rue du Prof. Descottes, Limoges 87000, France
- RCPTM, Department of Physical Chemistry, Faculty of Sciences, Palacký University, Olomouc 771 47, Czech Republic
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7
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Lu BS, Gupta SP, Belička M, Podgornik R, Pabst G. Modulation of Elasticity and Interactions in Charged Lipid Multibilayers: Monovalent Salt Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:13546-13555. [PMID: 27993014 PMCID: PMC5180256 DOI: 10.1021/acs.langmuir.6b03614] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/22/2016] [Indexed: 05/18/2023]
Abstract
We have studied the electrostatic screening effect of NaCl solutions on the interactions between anionic lipid bilayers in the fluid lamellar phase using a Poisson-Boltzmann-based mean-field approach with constant charge and constant potential limiting charge regulation boundary conditions. The full DLVO potential, including the electrostatic, hydration and van der Waals interactions, was coupled to thermal bending fluctuations of the membranes via a variational Gaussian Ansatz. This allowed us to analyze the coupling between the osmotic pressure and the fluctuation amplitudes and compare them both simultaneously with their measured dependence on the bilayer separation, determined by the small-angle X-ray scattering experiments. High-structural resolution analysis of the scattering data revealed no significant changes of membrane structure as a function of salt concentration. Parsimonious description of our results is consistent with the constant charge limit of the general charge regulation phenomenology, with fully dissociated lipid charge groups, together with a 6-fold reduction of the membranes' bending rigidity upon increasing NaCl concentration.
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Affiliation(s)
- Bing-Sui Lu
- Department
of Theoretical Physics, Jožef Stefan
Institute, 1000 Ljubljana, Slovenia
- School
of Physical and Mathematical Sciences, Nanyang
Technological University, 21 Nanyang Link, 637371 Singapore
- E-mail:
| | - Santosh Prasad Gupta
- Institute
of Molecular Biosciences, Biophysics Division,University of Graz, NAWI Graz, Humboldtstraße 50/III, A-8010 Graz, Austria
- BioTechMed-Graz, A-8010 Graz, Austria
| | - Michal Belička
- Institute
of Molecular Biosciences, Biophysics Division,University of Graz, NAWI Graz, Humboldtstraße 50/III, A-8010 Graz, Austria
- BioTechMed-Graz, A-8010 Graz, Austria
| | - Rudolf Podgornik
- Department
of Theoretical Physics, Jožef Stefan
Institute, 1000 Ljubljana, Slovenia
- Department
of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska ulica 19, SI-1000 Ljubljana, Slovenia
- E-mail:
| | - Georg Pabst
- Institute
of Molecular Biosciences, Biophysics Division,University of Graz, NAWI Graz, Humboldtstraße 50/III, A-8010 Graz, Austria
- BioTechMed-Graz, A-8010 Graz, Austria
- E-mail: . Phone: +43 316 380 4989
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8
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Yamamoto A, Abuillan W, Burk AS, Körner A, Ries A, Werz DB, Demé B, Tanaka M. Influence of length and conformation of saccharide head groups on the mechanics of glycolipid membranes: Unraveled by off-specular neutron scattering. J Chem Phys 2016; 142:154907. [PMID: 25903910 DOI: 10.1063/1.4918585] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The mechanical properties of multilayer stacks of Gb3 glycolipid that play key roles in metabolic disorders (Fabry disease) were determined quantitatively by using specular and off-specular neutron scattering. Because of the geometry of membrane stacks deposited on planar substrates, the scattered intensity profile was analyzed in a 2D reciprocal space map as a function of in-plane and out-of-plane scattering vector components. The two principal mechanical parameters of the membranes, namely, bending rigidity and compression modulus, can be quantified by full calculation of scattering functions with the aid of an effective cut-off radius that takes the finite sample size into consideration. The bulkier "bent" Gb3 trisaccharide group makes the membrane mechanics distinctly different from cylindrical disaccharide (lactose) head groups and shorter "bent" disaccharide (gentiobiose) head groups. The mechanical characterization of membranes enriched with complex glycolipids has high importance in understanding the mechanisms of diseases such as sphingolipidoses caused by the accumulation of non-degenerated glycosphingolipids in lysosomes or inhibition of protein synthesis triggered by the specific binding of Shiga toxin to Gb3.
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Affiliation(s)
- Akihisa Yamamoto
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
| | - Wasim Abuillan
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
| | - Alexandra S Burk
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
| | - Alexander Körner
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
| | - Annika Ries
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, 37077 Göttingen, Germany
| | - Daniel B Werz
- Institute of Organic Chemistry, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Bruno Demé
- Institut Laue-Langevin, 38042 Grenoble Cedex 9, Grenoble, France
| | - Motomu Tanaka
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
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9
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PABST GEORG. GLOBAL PROPERTIES OF BIOMIMETIC MEMBRANES: PERSPECTIVES ON MOLECULAR FEATURES. ACTA ACUST UNITED AC 2011. [DOI: 10.1142/s1793048006000069] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Global properties of biological model membranes such as, e.g., structure or elasticity, are known to be closely related to their local features. If a membrane active compound interacts with the membrane assembly, the membrane will primarily be affected on the local, molecular level. The local perturbation may than, through some coupling, translate into a global adjustment of the membrane. In order to address this coupling x-ray and neutron diffraction data analysis techniques have been developed that allow accurate monitoring of changes in global properties. This offers new perspectives on molecular membrane features that in combination with complementary techniques, such as differential scanning calorimetry, spectroscopy or dynamic scattering lead to a better understanding of biomimetic membranes. The present article reviews these aspects giving application examples for single- and multicomponent membranes, respectively.
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Affiliation(s)
- GEORG PABST
- Institute of Biophysics and X-ray Structure Research, Austrian Academy of Sciences, Schmiedlstraße 6, Graz, 8042, Austria
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10
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Ulmschneider JP, Smith JC, White SH, Ulmschneider MB. In silico partitioning and transmembrane insertion of hydrophobic peptides under equilibrium conditions. J Am Chem Soc 2011; 133:15487-95. [PMID: 21861483 PMCID: PMC3191535 DOI: 10.1021/ja204042f] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nascent transmembrane (TM) polypeptide segments are recognized and inserted into the lipid bilayer by the cellular translocon machinery. The recognition rules, described by a biological hydrophobicity scale, correlate strongly with physical hydrophobicity scales that describe the free energy of insertion of TM helices from water. However, the exact relationship between the physical and biological scales is unknown, because solubility problems limit our ability to measure experimentally the direct partitioning of hydrophobic peptides across lipid membranes. Here we use microsecond molecular dynamics (MD) simulations in which monomeric polyleucine segments of different lengths are allowed to partition spontaneously into and out of lipid bilayers. This approach directly reveals all states populated at equilibrium. For the hydrophobic peptides studied here, only surface-bound and transmembrane-inserted helices are found. The free energy of insertion is directly obtained from the relative occupancy of these states. A water-soluble state was not observed, consistent with the general insolubility of hydrophobic peptides. The approach further allows determination of the partitioning pathways and kinetics. Surprisingly, the transfer free energy appears to be independent of temperature, which implies that surface-to-bilayer peptide insertion is a zero-entropy process. We find that the partitioning free energy of the polyleucine segments correlates strongly with values from translocon experiments but reveals a systematic shift favoring shorter peptides, suggesting that translocon-to-bilayer partitioning is not equivalent but related to spontaneous surface-to-bilayer partitioning.
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Affiliation(s)
| | - Jeremy C. Smith
- IWR, University of Heidelberg, Germany
- Oak Ridge National Laboratory, Oak Ridge TN, USA
| | - Stephen H. White
- Department of Physiology & Biophysics, University of California at Irvine, Irvine CA, USA
| | - Martin B. Ulmschneider
- Department of Physiology & Biophysics, University of California at Irvine, Irvine CA, USA
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11
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Abstract
Highly aligned, substrate supported membranes have made it possible for physical techniques to extract unambiguous structural information previously not accessible from commonly available membrane dispersions, or so-called powder samples. This review will highlight some of the major breakthroughs in model membrane research that have taken place as a result of substrate supported samples.
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12
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Pabst G, Kucerka N, Nieh MP, Rheinstädter MC, Katsaras J. Applications of neutron and X-ray scattering to the study of biologically relevant model membranes. Chem Phys Lipids 2010; 163:460-79. [PMID: 20361949 DOI: 10.1016/j.chemphyslip.2010.03.010] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 03/23/2010] [Accepted: 03/24/2010] [Indexed: 11/19/2022]
Abstract
Scattering techniques, in particular electron, neutron and X-ray scattering have played a major role in elucidating the static and dynamic structure of biologically relevant membranes. Importantly, neutron and X-ray scattering have evolved to address new sample preparations that better mimic biological membranes. In this review, we will report on some of the latest model membrane results, and the neutron and X-ray techniques that were used to obtain them.
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Affiliation(s)
- G Pabst
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, A-8042 Graz, Austria
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13
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Pérez-Berná AJ, Pabst G, Laggner P, Villalaín J. Biophysical characterization of the fusogenic region of HCV envelope glycoprotein E1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2183-93. [PMID: 19698697 DOI: 10.1016/j.bbamem.2009.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 07/27/2009] [Accepted: 08/04/2009] [Indexed: 01/08/2023]
Abstract
We have studied the binding and interaction of the peptide E1(FP) with various model membranes. E1(FP) is derived from the amino acid segment 274-291 of the hepatitis C virus envelope glycoprotein E1, which was previously proposed to host the peptide responsible for fusion to target membranes. In the present study we addressed the changes which take place upon E1(FP) binding in both the peptide and the phospholipid bilayer, respectively, through a series of complementary experiments. We show that peptide E1(FP) binds to and interacts with phospholipid model membranes, modulates the polymorphic phase behavior of membrane phospholipids, is localized in a shallow position in the membrane and interacts preferentially with cholesterol. The capability of modifying the biophysical properties of model membranes supports its role in HCV-mediated membrane fusion and suggests that the mechanism of membrane fusion elicited by class I and II fusion proteins might be similar.
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Affiliation(s)
- Ana J Pérez-Berná
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, E-03202 Alicante, Spain
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14
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Hishida M, Seto H, Yamada N, Yoshikawa K. Hydration process of multi-stacked phospholipid bilayers to form giant vesicles. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.02.065] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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15
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Abstract
We investigated the phase behavior of double-tail lipids, as a function of temperature, headgroup interaction and tail length. At low values of the head-head repulsion parameter a(hh), the bilayer undergoes with increasing temperature the transitions from the subgel phase L(c) via the flat gel phase L(beta) to the fluid phase L(alpha). For higher values of a(hh), the transition from the L(c) to the L(alpha) phase occurs via the tilted gel phase L(beta)(') and the rippled phase P(beta)('). The occurrence of the L(beta)(') phase depends on tail length. We find that the rippled structure (P(beta)(')) occurs if the headgroups are sufficiently surrounded by water and that the ripple is a coexistence between the L(c) or L(beta)(') phase and the L(alpha) phase. The anomalous swelling, observed at the P(beta)(') --> L(alpha) transition, is not directly related to the rippled phase, but a consequence of conformational changes of the tails.
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Affiliation(s)
- Marieke Kranenburg
- The Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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16
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Salditt T, Li C, Spaar A. Structure of antimicrobial peptides and lipid membranes probed by interface-sensitive X-ray scattering. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1483-98. [DOI: 10.1016/j.bbamem.2006.08.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Revised: 08/04/2006] [Accepted: 08/04/2006] [Indexed: 10/24/2022]
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17
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Li C, Salditt T. Structure of magainin and alamethicin in model membranes studied by x-ray reflectivity. Biophys J 2006; 91:3285-300. [PMID: 16920839 PMCID: PMC1614476 DOI: 10.1529/biophysj.106.090118] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have investigated the structure of lipid bilayers containing varied molar ratios of different lipids and the antimicrobial peptides magainin and alamethicin. For this structural study, we have used x-ray reflectivity on highly aligned solid-supported multilamellar lipid membranes. The reflectivity curves have been analyzed by semi-kinematical reflectivity theory modeling the bilayer density profile rho(z). Model simulations of the reflectivity curves cover a large range of vertical momentum transfer q(z), and yield excellent agreement between data and theory. The structural changes observed as a function of the molar peptide/lipid concentration P/L are discussed in a comparative way.
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Affiliation(s)
- C Li
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
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18
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Hishida M, Seto H, Kaewsaiha P, Matsuoka H, Yoshikawa K. Stacking structures of dry phospholipid films on a solid substrate. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2005.11.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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19
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Hayakawa T, Hirano Y, Makino A, Michaud S, Lagarde M, Pageaux JF, Doutheau A, Ito K, Fujisawa T, Takahashi H, Kobayashi T. Differential Membrane Packing of Stereoisomers of Bis(monoacylglycero)phosphate. Biochemistry 2006; 45:9198-209. [PMID: 16866366 DOI: 10.1021/bi060722o] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bis(monoacylglycero)phosphate (BMP) reveals an unusual sn-1,sn-1' stereoconfiguration of glycerophosphate. We synthesized sn-(3-myristoyl-2-hydroxy)glycerol-1-phospho-sn-1'-(3'-myristoyl-2'-hydroxy)glycerol (1,1'-DMBMP) and characterized the thermotropic phase behavior and membrane structure, in comparison with those of the corresponding sn-3:sn-1' stereoisomer (3,1'-DMBMP), by means of differential scanning calorimetry (DSC), small- and wide-angle X-ray scattering (SAXS and WAXS, respectively), pressure-area (pi-A) isotherms, epifluorescence microscopy of monolayers, and molecular dynamics (MD) simulations. In DSC, these lipids exhibited weakly energetic broad peaks with an onset temperature of 9 degrees C for 1,1'-DMBMP and 18 degrees C for 3,1'-DMBMP. In addition, a highly cooperative, strongly energetic transition peak was observed at approximately 40 degrees C for 1,1'-DMBMP and approximately 42 degrees C for 3,1'-DMBMP. These results are supported by the observation that 1,1'-DMBMP exhibited a larger phase transition pressure (pi(c)) than 3,1'-DMBMP. Small- and wide-angle X-ray scattering measurements identified these small and large energetic transitions as a quasi-crystalline (L(c1))-quasi-crystalline with different tilt angle (L(c2)) phase transition and an L(c2)-L(alpha) main phase transition, respectively. X-ray measurements also revealed that these DMBMPs undergo an unbinding at the main phase transition temperature. The MD simulations estimated stronger hydrogen bonding formation in the 3,1'-DMBMP membrane than in 1,1'-DMBMP, supporting the experimental data.
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Affiliation(s)
- Tomohiro Hayakawa
- Lipid Biology Laboratory, RIKEN (Institute of Physical and Chemical Research), 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan
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20
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Komura S, Shimokawa N, Kato T. Unbinding and preunbinding in surfactant solutions. J Chem Phys 2006; 124:034906. [PMID: 16438613 DOI: 10.1063/1.2159475] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We propose models for the first-order unbinding transition of lyotropic lamellae in surfactant solutions. The coupling between the surfactant volume fraction and the elastic degree of freedom is considered so that the net attractive interaction between the surfactant molecules is enhanced. The elastic degree of freedom can be either (i) a membrane elastic degree of freedom or (ii) a bulk elastic degree of freedom. The phase behaviors of these two models are analyzed. For both cases, the unbinding transition becomes first order when the coupling is strong enough. We determine the associated preunbinding line which separates two lamellar phases having different repeat distances.
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Affiliation(s)
- S Komura
- Department of Chemistry, Faculty of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan.
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21
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Smooth/rough layering in liquid-crystalline/gel state of dry phospholipid film, in relation to its ability to generate giant vesicles. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.06.045] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Rheinstädter MC, Seydel T, Demmel F, Salditt T. Molecular motions in lipid bilayers studied by the neutron backscattering technique. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 71:061908. [PMID: 16089766 DOI: 10.1103/physreve.71.061908] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2005] [Indexed: 05/03/2023]
Abstract
We report a high energy-resolution neutron backscattering study to investigate slow motions on nanosecond time scales in highly oriented solid supported phospholipid bilayers of the model system DMPC-d54 (deuterated 1,2-dimyristoyl-sn-glycero-3-phoshatidylcholine), hydrated with heavy water. This technique allows to discriminate the onset of mobility at different length scales for the different molecular components, as, e.g., the lipid acyl-chains and the hydration water in between the membrane stacks, respectively, and provides a benchmark test regarding the feasibility of neutron backscattering investigations on these sample systems. We discuss freezing of the lipid acyl-chains, as observed by this technique, and observe a second freezing transition which we attribute to the hydration water.
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Affiliation(s)
- Maikel C Rheinstädter
- Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France.
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23
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Hu SX, Li XH, Jia QJ, Mai ZH, Li M. Temperature dependence of interfacial fluctuations of polymerized fatty acid salt multilayers. J Chem Phys 2005; 122:124712. [PMID: 15836414 DOI: 10.1063/1.1865952] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
X-ray scattering was used to study the temperature dependence of the profile structure of polymerized 10,12-tricosadiynoic acid salt multilayers. The stacking periodicity of the multilayers was found to decrease with increasing temperature due to the conformational changes of the alkyl chains. When the samples were fully hydrated in water, the reflectivity measurement showed that the thermal fluctuations of the interfaces are enhanced with temperature, resulting in reduced ordering. Meanwhile, the diffuse scattering indicated that the thermal fluctuations renormalize the elasticity of the multilayers; both the bending and the compression moduli are reduced. Similar measurements performed in air, however, do not show this thermal enhancement although the stacking periodicity decreases in the same manner. It is implied that water might weaken the interaction between the carboxyl groups and the metal ions so that the polymerized bilayers are softened in water.
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Affiliation(s)
- Shu-Xin Hu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
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24
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Pabst G, Amenitsch H, Kharakoz DP, Laggner P, Rappolt M. Structure and fluctuations of phosphatidylcholines in the vicinity of the main phase transition. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 70:021908. [PMID: 15447516 DOI: 10.1103/physreve.70.021908] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Revised: 04/05/2004] [Indexed: 05/24/2023]
Abstract
We have determined the structural properties and bending fluctuations of fully hydrated phosphatidylcholine multibilayers in the fluid (Lalpha) phase, as well as the structure of the ripple (Pbeta') phase near the main phase transition temperature (TM) by x-ray diffraction. The number of carbons, nHC, per acyl chain of the studied disaturated lipids varied from 14 to 22. All lipids exhibit a nonlinear increase of the lamellar repeat distance d in the Lalpha phase upon approaching TM, known as "anomalous swelling." The nonlinear increase reduces with chain length, but levels off at a constant value of about 0.5 A for lipids with more than 18 hydrocarbons per chain. A detailed analysis shows that anomalous swelling has two components. One is due to an expansion of the water layer, which decreases with chain length and finally vanishes for nHC >18. The second component is due to a bilayer thickness increase, which remains unchanged in its temperature dependence, including a nonlinear component of about 0.5 A in the vicinity of TM. Thus, anomalous swelling above 18 hydrocarbons per chain is due to the pretransitional effects on the membrane only. These results are supported by a bending fluctuation analysis revealing increased undulations close to TM only for the short chain lipids. We have further calculated the electron density maps in the ripple phase and find no coupling of the magnitude of the ripple amplitude to the chain length effects observed in the Lalpha phase. Hence, in agreement with an earlier report by Mason et al. [Phys. Rev. E 63, 030902 (2001)] there is no connection between the formation of the ripple phase and anomalous swelling.
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Affiliation(s)
- G Pabst
- Institute of Biophysics and X-Ray Structure Research, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria.
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25
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Amenitsch H, Rappolt M, Teixeira CV, Majerowicz M, Laggner P. In situ sensing of salinity in oriented lipid multilayers by surface X-ray scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:4621-8. [PMID: 15969174 DOI: 10.1021/la036319p] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The influence of LiCl solutions on liposomal and surface-supported phosphatidylcholine/water systems (dipalmitoylphosphatidylcholine (DPPC) and 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), respectively) has been studied by small-angle X-ray techniques. In liposomal dispersions of DPPC, an osmotically stressed liquid-crystalline phase, denoted as Lalpha osm, forms readily after rapid mixing with salt solutions. The transition from Lalpha -->Lalpha osm proceeds in two steps. The first step takes place within seconds and is due to water diffusion from the liposome into the bulk solution. The second, slower process (minutes) can be attributed to the relaxation of initially deformed intermediate liposomes into spherical ones. In experiments with aligned lipid bilayers supported on silicon wafers, it was possible to reproducibly exchange different concentrations of LiCl solutions on a single sample and to determine the lattice changes by time-resolved X-ray scattering at grazing incidence. Independently of the deposition technique (spray- or spin-coating, respectively), none of the investigated POPC samples displayed an osmotically stressed liquid-crystalline phase. While liposomes can be considered nearly defect-free, supported bilayer stacks show a high abundance of defects, such as oily streaks typical of the Lalpha phase. Thus, the alkali ions are free to diffuse into the interbilayer water regions and to cause a slight increase of the bilayer separation (about 1 Angstroms). It is concluded that low to medium concentrations of Li+ ions partially screen the attractive van der Waals force between adjacent membrane layers. However, upon annealing the defect regions or regions of high curvature in the oriented lipid matrix, e.g. by low amounts of oleyl alcohol (OA), the system is able to sense osmotic stress upon addition of a salt solution.
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Affiliation(s)
- Heinz Amenitsch
- Institute of Biophysics and X-ray Structure Research, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria
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26
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Harroun TA, Nieh MP, Watson MJ, Raghunathan VA, Pabst G, Morrow MR, Katsaras J. Relationship between the unbinding and main transition temperatures of phospholipid bilayers under pressure. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 69:031906. [PMID: 15089321 DOI: 10.1103/physreve.69.031906] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2003] [Indexed: 05/24/2023]
Abstract
Using neutron diffraction and a specially constructed high pressure cell suitable for aligned multibilayer systems, we have studied, as a function of pressure, the much observed anomalous swelling regime in dimyristoyl- and dilauroyl-phosphatidylcholine bilayers, DMPC and DLPC, respectively. We have also reanalyzed data from a number of previously published experiments and have arrived at the following conclusions. (a). The power law behavior describing anomalous swelling is preserved in all PC bilayers up to a hydrostatic pressure of 240 MPa. (b). As a function of increasing pressure there is a concomitant decrease in the anomalous swelling of DMPC bilayers. (c). For PC lipids with hydrocarbon chains >or=13 carbons the theoretical unbinding transition temperature T small star, filled is coupled to the main gel-to-liquid crystalline transition temperature T(M). (d). DLPC is intrinsically different from the other lipids studied in that its T small star, filled is not coupled to T(M). (e). For DLPC bilayers we predict a hydrostatic pressure (>290 MPa) where unbinding may occur.
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Affiliation(s)
- T A Harroun
- National Research Council, Steacie Institute for Molecular Sciences, Chalk River, Ontario, Canada K0J 1J0
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27
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Structural features of a cationic gemini surfactant at full hydration investigated by energy dispersive X-ray diffraction. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.01.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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28
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Salditt T. Lipid-peptide interaction in oriented bilayers probed by interface-sensitive scattering methods. Curr Opin Struct Biol 2003; 13:467-78. [PMID: 12948776 DOI: 10.1016/s0959-440x(03)00113-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Oriented lipid membranes deposited on solid substrates offer unique experimental opportunities to study lipid bilayer structure and lipid-peptide interaction in suitable model systems. In particular, modern interface-sensitive X-ray and neutron scattering methods can be used to probe the short-range order and molecular conformations of peptides and lipids in the fluid state of the bilayer.
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Affiliation(s)
- Tim Salditt
- Institüt für Röntgenphysik, Universität Göttingen, Geiststrasse 11, D-37037 Göttingen, Germany.
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29
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Pozo-Navas B, Raghunathan VA, Katsaras J, Rappolt M, Lohner K, Pabst G. Discontinuous unbinding of lipid multibilayers. PHYSICAL REVIEW LETTERS 2003; 91:028101. [PMID: 12906511 DOI: 10.1103/physrevlett.91.028101] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2003] [Indexed: 05/24/2023]
Abstract
We have observed a discontinuous unbinding transition of lipid bilayer stacks composed of phosphatidylethanolamine and phosphatidylglycerol using x-ray diffraction. The unbinding is reversible and coincides with the main (L(beta)-->L(alpha)) transition of the lipid mixture. Interbilayer interaction potentials deduced from the diffraction data reveal that the bilayers in the L(beta) phase are only weakly bound. The unbinding transition appears to be driven by an abrupt increase in steric repulsion resulting from increased thermal undulations of the bilayers upon entering the fluid L(alpha) phase.
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Affiliation(s)
- B Pozo-Navas
- Institute of Biophysics and X-Ray Structure Research, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria
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