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Akutsu H. Structure and dynamics of phospholipids in membranes elucidated by combined use of NMR and vibrational spectroscopies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183352. [DOI: 10.1016/j.bbamem.2020.183352] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 12/17/2022]
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Luviano AS, Campos-Terán J, Langevin D, Castillo R, Espinosa G. Mechanical Properties of DPPC-POPE Mixed Langmuir Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16734-16744. [PMID: 31790592 DOI: 10.1021/acs.langmuir.9b02995] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The mechanical properties of lipid monolayers and their responses to shear and compression stresses play an important role in processes such as breathing and eye blinking. We studied the mechanical properties of Langmuir monolayers of a model mixture, composed of an unsaturated lipid, 1-palmitoyl-2-oleoyl-sn-glycero-phosphoethanolamine (POPE), and a saturated lipid, 1,2-dipalmitoyl-sn-glycero-phosphocholine (DPPC). We performed isothermal compressions and sinusoidal shear deformations of these mixed monolayers. Also, the different phases were observed with Brewster angle microscopy. We found that the mechanical behavior is affected by the miscibility of both lipids. In the two-phase region, the compression elastic modulus increases with the amount of the LC phase but does not follow the predictions of a simple effective medium model. The discrepancies arise from the fact that, upon compression, the domains grow at a rate faster than the compression rate but not fast enough to reach thermodynamic equilibrium. Before reaching the LC phase, domain percolation is observed and compression and shear moduli become equal to those of the pure LC phase. Most of the monolayers behave as viscoelastic fluids at the frequencies investigated. A minimum in the compression modulus and shear viscosity was observed for mixtures close to equimolar composition, with the minimum being accompanied by a change in domain shapes.
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Affiliation(s)
- Alberto S Luviano
- Instituto de Física y Matemáticas , Universidad Michoacana de San Nicolás de Hidalgo , 58060 Morelia , México
| | - José Campos-Terán
- Departamento de Procesos y Tecnología , Universidad Autónoma Metropolitana, Unidad Cuajimalpa , 05348 Ciudad de México , México
| | - Dominique Langevin
- Laboratoire de Physique des Solides , Université Paris-Sud , 91405 Orsay , France
| | - Rolando Castillo
- Instituto de Física , Universidad Autónoma de México , P.O. Box 20-264, 01000 Ciudad de México , México
| | - Gabriel Espinosa
- Instituto de Física y Matemáticas , Universidad Michoacana de San Nicolás de Hidalgo , 58060 Morelia , México
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Saotome K, Duong-Ly KC, Howard KP. Influenza A M2 protein conformation depends on choice of model membrane. Biopolymers 2016; 104:405-11. [PMID: 25652904 DOI: 10.1002/bip.22617] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/17/2015] [Accepted: 01/24/2015] [Indexed: 11/08/2022]
Abstract
While crystal and NMR structures exist of the influenza A M2 protein, there is disagreement between models. Depending on the requirements of the technique employed, M2 has been studied in a range of membrane mimetics including detergent micelles and membrane bilayers differing in lipid composition. The use of different model membranes complicates the integration of results from published studies necessary for an overall understanding of the M2 protein. Here we show using site-directed spin-label EPR spectroscopy (SDSL-EPR) that the conformations of M2 peptides in membrane bilayers are clearly influenced by the lipid composition of the bilayers. Altering the bilayer thickness or the lateral pressure profile within the bilayer membrane changes the M2 conformation observed. The multiple M2 peptide conformations observed here, and in other published studies, optimistically may be considered conformations that are sampled by the protein at various stages during influenza infectivity. However, care should be taken that the heterogeneity observed in published structures is not simply an artifact of the choice of the model membrane.
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Affiliation(s)
- Kei Saotome
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081
| | - Krisna C Duong-Ly
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081
| | - Kathleen P Howard
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081
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Dawaliby R, Trubbia C, Delporte C, Noyon C, Ruysschaert JM, Van Antwerpen P, Govaerts C. Phosphatidylethanolamine Is a Key Regulator of Membrane Fluidity in Eukaryotic Cells. J Biol Chem 2015; 291:3658-67. [PMID: 26663081 DOI: 10.1074/jbc.m115.706523] [Citation(s) in RCA: 230] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Indexed: 01/10/2023] Open
Abstract
Adequate membrane fluidity is required for a variety of key cellular processes and in particular for proper function of membrane proteins. In most eukaryotic cells, membrane fluidity is known to be regulated by fatty acid desaturation and cholesterol, although some cells, such as insect cells, are almost devoid of sterol synthesis. We show here that insect and mammalian cells present similar microviscosity at their respective physiological temperature. To investigate how both sterols and phospholipids control fluidity homeostasis, we quantified the lipidic composition of insect SF9 and mammalian HEK 293T cells under normal or sterol-modified condition. As expected, insect cells show minimal sterols compared with mammalian cells. A major difference is also observed in phospholipid content as the ratio of phosphatidylethanolamine (PE) to phosphatidylcholine (PC) is inverted (4 times higher in SF9 cells). In vitro studies in liposomes confirm that both cholesterol and PE can increase rigidity of the bilayer, suggesting that both can be used by cells to maintain membrane fluidity. We then show that exogenously increasing the cholesterol amount in SF9 membranes leads to a significant decrease in PE:PC ratio whereas decreasing cholesterol in HEK 293T cells using statin treatment leads to an increase in the PE:PC ratio. In all cases, the membrane fluidity is maintained, indicating that both cell types combine regulation by sterols and phospholipids to control proper membrane fluidity.
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Affiliation(s)
- Rosie Dawaliby
- From the Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, CP 206/02, Bd du Triomphe, 1050 Brussels, Belgium
| | - Cataldo Trubbia
- From the Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, CP 206/02, Bd du Triomphe, 1050 Brussels, Belgium
| | - Cédric Delporte
- Laboratory of Pharmaceutical Chemistry and Analytical Platform of the Faculty of Pharmacy, Faculty of Pharmacy, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Caroline Noyon
- Laboratory of Pharmaceutical Chemistry and Analytical Platform of the Faculty of Pharmacy, Faculty of Pharmacy, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Jean-Marie Ruysschaert
- From the Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, CP 206/02, Bd du Triomphe, 1050 Brussels, Belgium
| | - Pierre Van Antwerpen
- Laboratory of Pharmaceutical Chemistry and Analytical Platform of the Faculty of Pharmacy, Faculty of Pharmacy, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Cédric Govaerts
- From the Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, CP 206/02, Bd du Triomphe, 1050 Brussels, Belgium,
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Bach D, Epand R, Epand R, Miller I, Wachtel E. The oxysterol 3β-hydroxy-5-oxo-5,6-secocholestan-6-al changes the phase behavior and structure of phosphatidylethanolamine–phosphatidylcholine mixtures. Chem Phys Lipids 2011; 164:672-9. [DOI: 10.1016/j.chemphyslip.2011.06.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 06/26/2011] [Accepted: 06/28/2011] [Indexed: 11/25/2022]
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6
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Ahn T, Chi YT, Yun CH. Effect of nonlamellar-prone lipids on protein encapsulation in liposomes. Macromol Res 2009. [DOI: 10.1007/bf03218642] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
A solvent-free coarse-grained model for a 1:1 mixed dioleoylphosphatidylcholine (DOPC) and a dioleoylphospatidylethanolamine (DOPE) bilayer is developed using the multiscale coarse-graining (MS-CG) approach. B-spline basis functions are implemented instead of the original cubic spline basis functions in the MS-CG method. The new B-spline basis functions are able to dramatically reduce memory requirements and increase computational efficiency of the MS-CG calculation. Various structural properties from the CG simulations are compared with their corresponding all-atom counterpart in order to validate the CG model. The resulting CG structural properties agree well with atomistic results, which shows that the MS-CG force field can reasonably approximate the many-body potential of mean force in the coarse-grained coordinates. Fast lipid lateral diffusion in the CG simulations, as a result of smoother free energy landscape, makes the study of phase behavior of the binary mixture possible. Small clusters of distinct lipid composition are identified by analyzing the DOPC/DOPE lipid lateral distribution, indicating a nonuniform distribution for the mixed bilayer. The results of lipid phase behavior are compared to experimental results, and connections between the experimental and simulation conclusions are discussed.
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Affiliation(s)
- Lanyuan Lu
- Center for Biophysical Modeling and Simulation and Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, USA
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Ahn T, Yun CH, Oh DB. Involvement of nonlamellar-prone lipids in the stability increase of human cytochrome P450 1A2 in reconstituted membranes. Biochemistry 2005; 44:9188-96. [PMID: 15966743 DOI: 10.1021/bi050051e] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effect of nonlamellar-prone lipids, diacylglycerol (DG) and phosphatidylethanolamine (PE), on the stability of human cytochrome P450 1A2 (CYP1A2) was examined. When 100% phosphatidylcholine (PC) in standard vesicles was gradually replaced with either DG or PE, the stability of CYP1A2 increased; the incubation time-dependent destruction of spectrally detectable P450, decrease of catalytic activity, reduction of intrinsic fluorescence, and increased sensitivity to trypsin digestion were significantly alleviated. The ternary system of PC/PE/DG increased the stability of CYP1A2 more, even at lower concentrations of each nonlamellar-prone lipid, than that of the binary lipid mixture (PC/nonlamellar lipid). By incorporating the nonlamellar-prone lipids, the CYP1A2-induced increase of the surface pressure of the lipid monolayer was much higher compared to that for 100% PC. Increased surface pressure indicates a deep insertion of the protein into lipid monolayers. Nonlamellar lipids also increased the transition temperature of CYP1A2 in thermal unfolding and reduced the incubation time-dependent detachment of membrane-bound CYP1A2 from vesicles. Taken together, these results suggest that nonlamellar lipids per se and/or the phase properties of the membrane containing these lipids are important in the enhanced stability of CYP1A2 and the concomitant maintenance of catalytic activity of the protein.
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Affiliation(s)
- Taeho Ahn
- Department of Biochemistry, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Korea.
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Domènech O, Torrent-Burgués J, Merino S, Sanz F, Montero MT, Hernández-Borrell J. Surface thermodynamics study of monolayers formed with heteroacid phospholipids of biological interest. Colloids Surf B Biointerfaces 2005; 41:233-8. [PMID: 15748818 DOI: 10.1016/j.colsurfb.2004.12.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Accepted: 12/20/2004] [Indexed: 11/18/2022]
Abstract
The interaction of 1-palmitoy-2-oleoyl-sn-glycero-3-phosphocoline (POPC) and 1-palmitoy-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), two of the major components in biological membranes, were investigated using the monolayer technique at the air-water interface. The pressure-area isotherms indicate that both phospholipids are miscible through all range of compositions. POPE-POPC form stable mixtures, with a minimum for the Gibbs energy of mixing at X(POPC) = 0.4. A virial equation of state was fitted to the experimental values. Positive values found for the second virial coefficient indicate repulsion between POPC and POPE. The interaction parameter was evaluated which indicated that a corresponding decrease in the repulsion occurs when POPC molar fraction is low. This effect suggests the existence of hydrogen bonds between POPE and the water beneath the interface.
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Affiliation(s)
- Oscar Domènech
- Departament de Química Física, Universitat de Barcelona, Centre de Bioelectrònica i Nanobiociència (CBEN), Parc Científic de Barcelona, Josep Samitier 1-5, E-08028 Barcelona, Spain
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Polozov IV, Gawrisch K. Domains in binary SOPC/POPE lipid mixtures studied by pulsed field gradient 1H MAS NMR. Biophys J 2005; 87:1741-51. [PMID: 15345553 PMCID: PMC1304579 DOI: 10.1529/biophysj.104.040725] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We studied domain formation in mixtures of the monounsaturated lipids SOPC and POPE as a function of temperature and composition by NMR. Magic angle spinning at kHz frequencies restored resolution of (1)H NMR lipid resonances in the fluid phase, whereas the linewidth of gel-phase lipids remained rather broad and spinning frequency dependent. In regions of fluid- and gel-phase coexistence, spectra are a superposition of resonances from fluid and gel domains, as indicated by the existence of isosbestic points. Quantitative determination of the amount of lipid in the coexisting phases is straightforward and permitted construction of a binary phase diagram. Lateral rates of lipid diffusion were determined by (1)H MAS NMR with pulsed field gradients. At the onset of the phase transition near 25 degrees C apparent diffusion rates became diffusion time dependent, indicating that lipid movement is obstructed by the formation of gel-phase domains. A percolation threshold at which diffusion of fluid-phase lipid becomes confined to micrometer-size domains was observed when approximately 40% of total lipid had entered the gel phase. The results indicate that common phosphatidylethanolamines may trigger domain formation in membranes within a physiologically relevant temperature range. This novel NMR approach may aid the study of lipid rafts.
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Affiliation(s)
- Ivan V Polozov
- Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland 20852, USA
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Malcharek S, Hinz A, Hilterhaus L, Galla HJ. Multilayer structures in lipid monolayer films containing surfactant protein C: effects of cholesterol and POPE. Biophys J 2005; 88:2638-49. [PMID: 15653721 PMCID: PMC1305360 DOI: 10.1529/biophysj.104.050823] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The influence of cholesterol and POPE on lung surfactant model systems consisting of DPPC/DPPG (80:20) and DPPC/DPPG/surfactant protein C (80:20:0.4) has been investigated. Cholesterol leads to a condensation of the monolayers, whereas the isotherms of model lung surfactant films containing POPE exhibit a slight expansion combined with an increased compressibility at medium surface pressure (10-30 mN/m). An increasing amount of liquid-expanded domains can be visualized by means of fluorescence light microscopy in lung surfactant monolayers after addition of either cholesterol or POPE. At surface pressures of 50 mN/m, protrusions are formed which differ in size and shape as a function of the content of cholesterol or POPE, but only if SP-C is present. Low amounts of cholesterol (10 mol %) lead to an increasing number of protrusions, which also grow in size. This is interpreted as a stabilizing effect of cholesterol on bilayers formed underneath the monolayer. Extreme amounts of cholesterol (30 mol %), however, cause an increased monolayer rigidity, thus preventing reversible multilayer formation. In contrast, POPE, as a nonbilayer lipid thought to stabilize the edges of protrusions, leads to more narrow protrusions. The lateral extension of the protrusions is thereby more influenced than their height.
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Affiliation(s)
- Stefan Malcharek
- Institut für Biochemie, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
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Kim KH, Ahn T, Yun CH. Membrane properties induced by anionic phospholipids and phosphatidylethanolamine are critical for the membrane binding and catalytic activity of human cytochrome P450 3A4. Biochemistry 2004; 42:15377-87. [PMID: 14690448 DOI: 10.1021/bi035280k] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human cytochrome P450 (CYP) 3A4, a membrane anchoring protein, is the major CYP enzyme present in both liver and small intestine. The enzyme plays a major role in the metabolism of many drugs and procarcinogens. The roles of individual phospholipids and membrane properties in the catalytic activity, membrane binding, and insertion into the membrane of CYP3A4 are poorly understood. Here we report that the catalytic activity of testosterone 6beta-hydroxylation, membrane binding, and membrane insertion of CYP3A4 increase as a function of anionic phospholipid concentration in the order phosphatidic acid (PA) > phosphatidylserine (PS) in a binary system of phosphatidylcholine (PC)/anionic phospholipid and as a function of phosphatidylethanolamine (PE) content in ternary systems of PC/PE/PA or PC/PE/PS having a fixed concentration of anionic phospholipids. These results suggest that PA and PE might help the binding of CYP3A4 to the membrane and the interaction with NPR. Cytochrome b(5) (b(5)) and apolipoprotein b(5) further enhanced the testosterone 6beta-hydroxylation activities of CYP3A4 in all tested phospholipids vesicles with various compositions. Phospholipid-dependent changes of the CYP3A4 conformation were also revealed by altered Trp fluorescence and CD spectra. We also found that PE induced the formation of anionic phospholipid-enriched domains in ternary systems using extrinsic fluorescent probes incorporated into lipid bilayers. Taken together, it can be suggested that the chemical and physical properties of membranes induced by anionic phospholipids and PE are critical for the membrane binding and catalytic activity of CYP3A4.
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Affiliation(s)
- Keon-Hee Kim
- Department of Genetic Engineering, Paichai University, Taejon 302-735, Korea
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de Vries AH, Mark AE, Marrink SJ. The Binary Mixing Behavior of Phospholipids in a Bilayer: A Molecular Dynamics Study. J Phys Chem B 2004. [DOI: 10.1021/jp0366926] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alex H. de Vries
- MD Group, Department of Biophysical Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Alan E. Mark
- MD Group, Department of Biophysical Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Siewert J. Marrink
- MD Group, Department of Biophysical Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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Abstract
Pyrene is one of the most frequently used lipid-linked fluorophores. Its most characteristic features are a long excited state lifetime and (local) concentration-dependent formation of excimers. Pyrene is also hydrophobic and thus does not significantly distort the conformation of the labeled lipid molecule. These characteristics make pyrene lipids well-suited for studies on a variety of biophysical phenomena like lateral diffusion, inter- or transbilayer movement of lipids and lateral organization of membranes. Pyrene lipids have also been widely employed to determine protein binding to membranes, lipid conformation and the activity of lipolytic enzymes. In cell biology, pyrene lipids are promising tools for studies on lipid trafficking and metabolism, as well as for microscopic mapping of membrane properties. The main disadvantage of pyrene lipids is the relatively large size of the fluorophore. Another disadvantage is that they require UV-excitation, which is not feasible with all microscopes.
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Affiliation(s)
- Pentti Somerharju
- Institute of Biomedicine, Biomedicum, Room C205b, Haartmaninkatu 8, P.O. Box 63, University of Helsinki, 00014 Helsinki, Finland.
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