1
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Birkenfeld KR, Gandhi TN, Simeral ML, Hafner JH. Cholesterol Conformational Structures in Phospholipid Membranes. J Phys Chem A 2024. [PMID: 39228182 DOI: 10.1021/acs.jpca.4c02860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Cholesterol is a major component of biomembranes that impacts membrane order, permeability, and lateral organization, but the precise molecular mechanisms of cholesterol's actions are still under investigation. Density functional theory (DFT) calculations have opened the fingerprint vibration bands of large molecules to detailed spectral analysis. For cholesterol, Raman spectral interpretation for conformational structure and hydrogen bonding is now possible. Here, DFT calculations of cholesterol conformers identify 10 structure types that also have unique low-frequency Raman spectra. By fitting experimental spectra to these types, the distribution of cholesterol structures present in phospholipid (PL) membrane vesicles was measured. The distributions reveal that the cholesterol iso-octyl chain tends to align with saturated PL chains and shifts to a thermal distribution for unsaturated PL chains. The results agree with the templating effect of cholesterol on PL membranes and show that the top of the iso-octyl chain is rigid like the rings. It is also shown that the inclusion of water molecules hydrogen bonded to the cholesterol hydroxy group in the DFT calculations may improve the spectral fitting for future studies.
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Affiliation(s)
- Kyra R Birkenfeld
- Department of Physics & Astronomy, Rice University, Houston, Texas 77005, United States
| | - Tia N Gandhi
- Department of Physics & Astronomy, Rice University, Houston, Texas 77005, United States
| | - Mathieu L Simeral
- Department of Physics & Astronomy, Rice University, Houston, Texas 77005, United States
| | - Jason H Hafner
- Department of Physics & Astronomy, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
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2
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Miyazaki M, Arisaka C, Nakagawara A, Sasaki N, Takahashi H, Takagi T, Amii H, Sonoyama M. Thermodynamic study on hydrated bilayers of ether-linked phosphatidylcholines with terminal perfluorobutyl group. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184261. [PMID: 38101595 DOI: 10.1016/j.bbamem.2023.184261] [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: 07/24/2023] [Revised: 11/01/2023] [Accepted: 12/07/2023] [Indexed: 12/17/2023]
Abstract
Novel terminally perfluorobutyl group-containing ether-linked phosphatidylcholines with different alkyl chain lengths (di-O-F4-Cn-PCs, n = 14,16 and 18) were developed as possible materials for stable liposomes aiming at applications of structural and functional analyses of membrane proteins. Differential scanning calorimetric investigations of the thermotropic transition of hydrated di-O-F4-Cn-PC bilayers demonstrated that the transition temperature of every di-O-F4-Cn-PC decreases by ~20 °C compared to their corresponding non-fluorinated PCs, di-O-Cn-PCs. With the elongation of the hydrophobic chain, on the other hand, the transition enthalpy (ΔH) and entropy (ΔS) increased in a linear manner. Comparison of ΔH and ΔS values against the net hydrocarbon chain length between di-O-F4-Cn-PCs and di-O-Cn-PCs strongly suggests that in the thermotropic transition of the di-O-F4-Cn-PC membrane, the perfluorobutyl segments undergo very limited structural changes; therefore, the hydrocarbon segments are mainly responsible for the phase transition.
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Affiliation(s)
- Masaya Miyazaki
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Chika Arisaka
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Ai Nakagawara
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Nanako Sasaki
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Hiroshi Takahashi
- Division of Pure and Applied Science, Graduate School of Science and Technology, Gunma University, Maebashi, Gunma 371-8510, Japan.
| | - Toshiyuki Takagi
- Cellular and Molecular Biotechnology Research Institute, AIST, Tsukuba, Ibaraki 305-8565, Japan.
| | - Hideki Amii
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan; Gunma University Initiative for Advanced Research (GIAR), Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Masashi Sonoyama
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan; Gunma University Initiative for Advanced Research (GIAR), Gunma University, Kiryu, Gunma 376-8515, Japan; Gunma University Center for Food Science and Wellness (GUCFW), Gunma University, Kiryu, Gunma 376-8515, Japan.
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3
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Träger J, Meister A, Hause G, Harauz G, Hinderberger D. Shaping membrane interfaces in lipid vesicles mimicking the cytoplasmic leaflet of myelin through variation of cholesterol and myelin basic protein contents. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184179. [PMID: 37244538 DOI: 10.1016/j.bbamem.2023.184179] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 04/23/2023] [Accepted: 05/20/2023] [Indexed: 05/29/2023]
Abstract
Myelin basic protein (MBP) is an intrinsically disordered protein and in the central nervous system (CNS) mainly responsible for connecting the cytoplasmic surfaces of the multilamellar, compact myelin. Increased posttranslational modification of MBP is linked to both, the natural development (from adolescent to adult brains) of myelin, and features of multiple sclerosis. Here, we study how a combination of this intrinsically disordered myelin protein with varying the natural cholesterol content may alter the characteristics of myelin-like membranes and interactions between these membranes. Large unilamellar vesicles (LUVs) with a composition mimicking the cytoplasmic leaflet of myelin were chosen as the model system, in which different parameters contributing to the interactions between the lipid membrane and MBP were investigated. While we use cryo-transmission electron microscopy (TEM) for imaging, dynamic light scattering (DLS) and electrophoretic measurements through continuously-monitored phase-analysis light scattering (cmPALS) were used for a more global overview of particle size and charge, and electron paramagnetic resonance (EPR) spectroscopy was utilized for local behavior of lipids in the vesicles' membranes in aqueous solution. The cholesterol content was varied from 060 % in these LUVs and measurements were performed in the presence and absence of MBP. We find that the composition of the lipid layers is relevant to the interaction with MBP. Not only the size, the shape and the aggregation behavior of the vesicles depend on the cholesterol content, but also within each membrane, cholesterol's freedom of movement, its environmental polarity and its distribution were found to depend on the content using the EPR-active spin-labeled cholesterol (CSOSL). In addition, DLS and EPR measurements probing the transition temperatures of the lipid phases allow a correlation of specific behavior with the human body temperature of 37 °C. Overall, our results aid in understanding the importance of the native cholesterol content in the healthy myelin membrane, which serves as the basis for stable and optimum protein-bilayer interactions. Although studied in this specific myelin-like system, from a more general and materials science-oriented point of view, we could establish how membrane and vesicle properties depend on cholesterol and/or MBP content, which might be useful generally when specific membrane and vesicle characteristics are sought for.
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Affiliation(s)
- Jennica Träger
- Institute of Chemistry, Physical Chemistry - Complex Self-organizing Systems, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Saxony-Anhalt, Germany; Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, Germany
| | - Annette Meister
- Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, Germany; Institute of Biochemistry, Physical Biotechnology, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Gerd Hause
- Biocenter, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - George Harauz
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Dariush Hinderberger
- Institute of Chemistry, Physical Chemistry - Complex Self-organizing Systems, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Saxony-Anhalt, Germany; Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, Germany.
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4
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Heller WT. Small-Angle Neutron Scattering for Studying Lipid Bilayer Membranes. Biomolecules 2022; 12:1591. [PMID: 36358941 PMCID: PMC9687511 DOI: 10.3390/biom12111591] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/18/2022] [Accepted: 10/26/2022] [Indexed: 09/23/2023] Open
Abstract
Small-angle neutron scattering (SANS) is a powerful tool for studying biological membranes and model lipid bilayer membranes. The length scales probed by SANS, being from 1 nm to over 100 nm, are well-matched to the relevant length scales of the bilayer, particularly when it is in the form of a vesicle. However, it is the ability of SANS to differentiate between isotopes of hydrogen as well as the availability of deuterium labeled lipids that truly enable SANS to reveal details of membranes that are not accessible with the use of other techniques, such as small-angle X-ray scattering. In this work, an overview of the use of SANS for studying unilamellar lipid bilayer vesicles is presented. The technique is briefly presented, and the power of selective deuteration and contrast variation methods is discussed. Approaches to modeling SANS data from unilamellar lipid bilayer vesicles are presented. Finally, recent examples are discussed. While the emphasis is on studies of unilamellar vesicles, examples of the use of SANS to study intact cells are also presented.
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Affiliation(s)
- William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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5
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Lau S, Middleton DA. Analysis of the orientation of cholesterol in high-density lipoprotein nanodiscs using solid-state NMR. Phys Chem Chem Phys 2022; 24:23651-23660. [PMID: 36134896 DOI: 10.1039/d2cp02393h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cholesterol is an essential component of eukaryotic cellular membranes that regulates the order and phase behaviour of dynamic lipid bilayers. Although cholesterol performs many vital physiological roles, hypercholesterolaemia and the accumulation of cholesterol in atherosclerotic plaques can increase the risk of coronary heart disease morbidity. The risk is mitigated by the transportation of cholesterol from peripheral tissue to the liver by high-density lipoprotein (HDL), 6-20 nm-diameter particles of lipid bilayers constrained by an annular belt of the protein apolipoprotein A-I (apoA-I). Information on the dynamics and orientation of cholesterol in HDL is pertinent to the essential role of HDL in cholesterol cycling. This work investigates whether the molecular orientation of cholesterol in HDL differs from that in the unconstrained lipid bilayers of multilamellar vesicles (MLVs). Solid-state NMR (ssNMR) measurements of dynamically-averaged 13C-13C and 13C-1H dipolar couplings were used to determine the average orientation of triple 13C-labelled cholesterol in palmitoyloleoylphosphatidylcholine (POPC) lipid bilayers in reconstituted HDL (rHDL) nanodiscs and in MLVs. Individual 13C-13C dipolar couplings were measured from [2,3,4-13C3]cholesterol in a one-dimensional NMR experiment, by using a novel application of a method to excite double quantum coherence at rotational resonance. The measured dipolar couplings were compared with average values calculated from orientational distributions of cholesterol generated using a Gaussian probability density function. The data were consistent with small differences in the average orientation of cholesterol in rHDL and MLVs, which may reflect the effects of the constrained and unconstrained lipid bilayers in the two environments. The calculated distributions of cholesterol in rHDL and MLVs that were consistent with the NMR data also agreed well with orientational distributions extracted from previous molecular dynamics simulations of HDL nanodiscs and planar POPC bilayers.
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Affiliation(s)
- Sophie Lau
- Department of Chemistry, Lancaster University, Bailrigg, Lancaster, UK.
| | - David A Middleton
- Department of Chemistry, Lancaster University, Bailrigg, Lancaster, UK.
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6
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Abstract
While it has long been established that cell membranes are complex assemblies of proteins and bilayer-forming lipids, the inherent mobility and wide-ranging heterogeneity of the lipids have limited our ability to understand cell-membrane structure at a molecular level. Consequently, little is yet known about the protein-lipid and lipid-lipid interplay that exists in situ. The present study exploits the regular architecture of a cholinergic cell membrane to determine how the phospholipid and cholesterol organization is influenced by the protein surfaces and by differences in cholesterol concentration between the two leaflets. Lipids in the leaflet containing the most cholesterol form an ordered sterol-hydrocarbon “skin.” This hitherto unobserved hydrophobic-core structure has far-reaching implications in terms of how cholesterol-rich membranes are constructed and function. Cell membranes are complex assemblies of proteins and lipids making transient or long-term associations that have yet to be characterized at a molecular level. Here, cryo-electron microscopy is applied to determine how phospholipids and cholesterol arrange between neighboring proteins (nicotinic acetylcholine receptors) of Torpedo cholinergic membrane. The lipids exhibit distinct properties in the two leaflets of the bilayer, influenced by the protein surfaces and by differences in cholesterol concentration. In the outer leaflet, the lipids show no consistent motif away from the protein surfaces, in keeping with their assumed fluidity. In the inner leaflet, where the cholesterol concentration is higher, the lipids organize into extensive close-packed linear arrays. These arrays are built from the sterol groups of cholesterol and the initial saturated portions of the phospholipid hydrocarbon chains. Together, they create an ordered ∼7 Å-thick “skin” within the hydrophobic core of the bilayer. The packing of lipids in the arrays appears to bear a close relationship to the linear cholesterol arrays that form crystalline monolayers at the air-water interface.
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7
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Ramezanpour M, Tieleman DP. Computational Insights into the Role of Cholesterol in Inverted Hexagonal Phase Stabilization and Endosomal Drug Release. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:7462-7471. [PMID: 35675506 PMCID: PMC9220946 DOI: 10.1021/acs.langmuir.2c00430] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 05/25/2022] [Indexed: 06/01/2023]
Abstract
Cholesterol is a major component of many lipid-based drug delivery systems, including cationic lipid nanoparticles. Despite its critical role in the drug release stage, the underlying molecular mechanism by which cholesterol assists in endosomal escape remains unclear. An efficient drug release from the endosome requires endosomal disruption. This disruption is believed to involve a lamellar-to-inverted hexagonal (Lα-HII) phase transition upon fusion of the lipid nanoparticle with the endosomal membrane. We used molecular dynamics simulations to study the structural properties of HII systems composed of an anionic lipid distearoyl phosphatidylserine (DSPS), an ionizable cationic lipid (KC2H), and cholesterol for several hydration levels and molar ratios. This system corresponds to the lipid mixtures in the hypothesized HII structure formed upon fusion and is of interest for the rational design of ionizable cationic lipids, including KC2, for an optimal drug release. Simulations suggest a geometry- and symmetry-driven lipid sorting and cholesterol-DSPS co-location around the water cores. Cholesterol preferentially co-locates with negatively charged saturated DSPS lipids at interstitial angles. The observed cholesterol-DSPS co-location results in an overall increase in the DSPS acyl chains' order parameters, which we propose to assist in stabilizing the HII phase by stretching the DSPS acyl chains for filling the voids formed by three adjacent lipid tubules. Furthermore, a systematic increase in the cholesterol concentration increased the lattice plane spacing and the water core radius but decreased the undulations along the lipid tubule axis. We propose that cholesterol and the degree of saturation/polyunsaturation of the lipid acyl chains, and not the lipid charge, are the main contributors in facilitating the Lα-HII phase transition and stabilizing/destabilizing the formed HII phase, whereas the positive charge of the ionizable cationic lipid promotes the LNP-endosomal membrane adhesion and assists in initiating the fusion process at the local contact area. We also propose that the effect of cholesterol on the HII structure and curvature is the main underlying reason for the well-documented HII stabilization and destabilization at low and high molar concentrations of cholesterol, respectively.
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8
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Unwin N. Protein-Lipid Interplay at the Neuromuscular Junction. Microscopy (Oxf) 2021; 71:i66-i71. [PMID: 34226930 PMCID: PMC8855523 DOI: 10.1093/jmicro/dfab023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/25/2021] [Accepted: 07/05/2021] [Indexed: 01/11/2023] Open
Abstract
Many new structures of membrane proteins have been determined over the last decade, yet the nature of protein–lipid interplay has received scant attention. The postsynaptic membrane of the neuromuscular junction and Torpedo electrocytes has a regular architecture, opening an opportunity to illuminate how proteins and lipids act together in a native membrane setting. Cryo electron microscopy (Cryo-EM) images show that cholesterol segregates preferentially around the constituent ion channel, the nicotinic acetylcholine receptor, interacting with specific sites in both leaflets of the bilayer. In addition to maintaining the transmembrane α-helical architecture, cholesterol forms microdomains – bridges of rigid sterol groups that link one channel to the next. This article discusses the whole protein–lipid organization of the cholinergic postsynaptic membrane, its physiological implications and how the observed details relate to our current concept of the membrane structure. I suggest that cooperative interactions, facilitated by the regular protein–lipid arrangement, help to spread channel activation into regions distant from the sites of neurotransmitter release, thereby enhancing the postsynaptic response.
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Affiliation(s)
- Nigel Unwin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, CB2 0QH, Cambridge, UK
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9
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Salvador-Castell M, Golub M, Erwin N, Demé B, Brooks NJ, Winter R, Peters J, Oger PM. Characterisation of a synthetic Archeal membrane reveals a possible new adaptation route to extreme conditions. Commun Biol 2021; 4:653. [PMID: 34079059 PMCID: PMC8172549 DOI: 10.1038/s42003-021-02178-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 04/29/2021] [Indexed: 02/04/2023] Open
Abstract
It has been proposed that adaptation to high temperature involved the synthesis of monolayer-forming ether phospholipids. Recently, a novel membrane architecture was proposed to explain the membrane stability in polyextremophiles unable to synthesize such lipids, in which apolar polyisoprenoids populate the bilayer midplane and modify its physico-chemistry, extending its stability domain. Here, we have studied the effect of the apolar polyisoprenoid squalane on a model membrane analogue using neutron diffraction, SAXS and fluorescence spectroscopy. We show that squalane resides inside the bilayer midplane, extends its stability domain, reduces its permeability to protons but increases that of water, and induces a negative curvature in the membrane, allowing the transition to novel non-lamellar phases. This membrane architecture can be transposed to early membranes and could help explain their emergence and temperature tolerance if life originated near hydrothermal vents. Transposed to the archaeal bilayer, this membrane architecture could explain the tolerance to high temperature in hyperthermophiles which grow at temperatures over 100 °C while having a membrane bilayer. The induction of a negative curvature to the membrane could also facilitate crucial cell functions that require high bending membranes.
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Affiliation(s)
| | - Maksym Golub
- Université Grenoble Alpes, CNRS, LiPhy, Grenoble, France
- Institut Laue Langevin, Grenoble, France
| | - Nelli Erwin
- Faculty of Chemistry and Chemical Biology, Technische Universität Dortmund, Dortmund, Germany
| | - Bruno Demé
- Institut Laue Langevin, Grenoble, France
| | | | - Roland Winter
- Faculty of Chemistry and Chemical Biology, Technische Universität Dortmund, Dortmund, Germany
| | - Judith Peters
- Université Grenoble Alpes, CNRS, LiPhy, Grenoble, France.
- Institut Laue Langevin, Grenoble, France.
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10
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Chen P, Vorobyov I, Roux B, Allen TW. Molecular Dynamics Simulations Based on Polarizable Models Show that Ion Permeation Interconverts between Different Mechanisms as a Function of Membrane Thickness. J Phys Chem B 2021; 125:1020-1035. [PMID: 33493394 DOI: 10.1021/acs.jpcb.0c08613] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Different mechanisms have been proposed to explain the permeation of charged compounds through lipid membranes. Overall, it is expected that an ion-induced defect permeation mechanism, where substantial membrane deformations accompany ion movement, should be dominant in thin membranes but that a solubility-diffusion mechanism, where ions partition into the membrane core with large associated dehydration energy costs, becomes dominant in thicker membranes. However, while this physical picture is intuitively reasonable, capturing the interconversion between these two permeation mechanisms in molecular dynamics (MD) simulations based on atomic models is challenging. In particular, simulations relying on nonpolarizable force fields are artificially unfavorable to the solubility-diffusion mechanism, as induced polarization of the nonpolar hydrocarbon is ignored, causing overestimated free energy costs for charged molecules to enter into this region of the membrane. In this study, all-atom MD simulations based on nonpolarizable and polarizable force fields are used to quantitatively characterize the permeation process for the arginine side chain analog methyl-guanidinium through bilayer membranes of mono-unsaturated phosphatidylcholine lipids with and without cholesterol, resulting in thicknesses spanning from ∼24 to ∼42 Å. With simulations based on a nonpolarizable force field, ion translocation can take place solely through an ion-induced defect mechanism, with free energy barriers increasing linearly from 14 to 40 kcal/mol, depending on the thickness. However, with simulations based on a polarizable force field, ion translocation is predominantly dominated by an ion-induced defect mechanism in thin membranes, which progressively converts to a solubility-diffusion mechanism as the membranes get thicker. The transition between the two mechanisms occurs at a thickness of ∼29 Å, with lipid tails of 22 or more carbon atoms. This situation appears to represent the upper limit for ion-induced defect permeation within the current polarizable models. Beyond this thickness, it becomes energetically preferable for the ion to dehydrate and partition into the membrane core-a phenomenon that cannot be captured using the nonpolarizable models. Induced electronic polarizability therefore leads not just to a shift in permeation energetics but to an interconversion between two strikingly different physical mechanisms. The result highlights the importance of induced polarizability in modeling lipid membranes.
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Affiliation(s)
- Peiran Chen
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Igor Vorobyov
- Department of Physiology & Membrane Biology, Department of Pharmacology, University of California, Davis, California 95616, United States
| | - Benoît Roux
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Toby W Allen
- School of Science, RMIT University, Melbourne 3001, Australia
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11
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Unwin N. Protein-lipid architecture of a cholinergic postsynaptic membrane. IUCRJ 2020; 7:852-859. [PMID: 32939277 PMCID: PMC7467168 DOI: 10.1107/s2052252520009446] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/10/2020] [Indexed: 05/06/2023]
Abstract
The cholinergic postsynaptic membrane is an acetyl-choline receptor-rich membrane mediating fast chemical communication at the nerve-muscle synapse. Here, cryo-EM is used to examine the protein-lipid architecture of this membrane in tubular vesicles obtained from the (muscle-derived) electric organ of the Torpedo ray. As reported earlier, the helical arrangement of the protein component of the vesicles facilitates image averaging and enables us to determine how cholesterol and phospho-lipid molecules are distributed in the surrounding matrix, using headgroup size as a means to discriminate between the two kinds of lipid. It is shown that cholesterol segregates preferentially around the receptors in both leaflets of the lipid bilayer, interacting robustly with specific transmembrane sites and creating a network of bridging microdomains. Cholesterol interactions with the receptor are apparently essential for stabilizing and maintaining its physiological architecture, since the transmembrane structure contracts, involving displacements of the helices at the outer membrane surface by ∼2 Å (1-3 Å), when this lipid is extracted. The microdomains may promote cooperativity between neighbouring receptors, leading to an enhanced postsynaptic response.
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Affiliation(s)
- Nigel Unwin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
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12
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Beddoes C, Gooris GS, Foglia F, Ahmadi D, Barlow DJ, Lawrence MJ, Demé B, Bouwstra JA. Arrangement of Ceramides in the Skin: Sphingosine Chains Localize at a Single Position in Stratum Corneum Lipid Matrix Models. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:10270-10278. [PMID: 32816488 PMCID: PMC7498151 DOI: 10.1021/acs.langmuir.0c01992] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Understanding the structure of the stratum corneum (SC) is essential to understand the skin barrier process. The long periodicity phase (LPP) is a unique trilayer lamellar structure located in the SC. Adjustments in the composition of the lipid matrix, as in many skin abnormalities, can have severe effects on the lipid organization and barrier function. Although the location of individual lipid subclasses has been identified, the lipid conformation at these locations remains uncertain. Contrast variation experiments via small-angle neutron diffraction were used to investigate the conformation of ceramide (CER) N-(tetracosanoyl)-sphingosine (NS) within both simplistic and porcine mimicking LPP models. To identify the lipid conformation of the twin chain CER NS, the chains were individually deuterated, and their scattering length profiles were calculated to identify their locations in the LPP unit cell. In the repeating trilayer unit of the LPP, the acyl chain of CER NS was located in the central and outer layers, while the sphingosine chain was located exclusively in the middle of the outer layers. Thus, for the CER NS with the acyl chain in the central layer, this demonstrates an extended conformation. Electron density distribution profiles identified that the lipid structure remains consistent regardless of the lipid's lateral packing phase, this may be partially due to the anchoring of the extended CER NS. The presented results provide a more detailed insight on the internal arrangement of the LPP lipids and how they are expected to be arranged in healthy skin.
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Affiliation(s)
- Charlotte
M. Beddoes
- Division
of BioTherapeutics, Leiden Academic Centre for Drug Research, University of Leiden, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Gert S. Gooris
- Division
of BioTherapeutics, Leiden Academic Centre for Drug Research, University of Leiden, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Fabrizia Foglia
- Chemistry
Department, Christopher Ingold Laboratories, University College London, London WC1H 0AJ, United Kingdom
| | - Delaram Ahmadi
- Pharmaceutical
Science Division, King’s College
London, London WC2R 2LS, United Kingdom
| | - David J. Barlow
- Pharmaceutical
Science Division, King’s College
London, London WC2R 2LS, United Kingdom
| | - M. Jayne Lawrence
- Division
of Pharmacy and Optometry, Manchester University, Manchester M13 9PL, United Kingdom
| | - Bruno Demé
- Institute
Laue-Langevin, Grenoble 38000, France
| | - Joke A. Bouwstra
- Division
of BioTherapeutics, Leiden Academic Centre for Drug Research, University of Leiden, Einsteinweg 55, Leiden 2333 CC, The Netherlands
- . Tel: 00 31 71 527 4208. Fax: 00 31 71 527 4565
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13
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Cheu C, Yang L, Nieh MP. Refining internal bilayer structure of bicelles resolved by extended-q small angle X-ray scattering. Chem Phys Lipids 2020; 231:104945. [PMID: 32621811 DOI: 10.1016/j.chemphyslip.2020.104945] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 06/18/2020] [Accepted: 06/26/2020] [Indexed: 11/15/2022]
Abstract
The internal profile across the bilayer reveals important structural information regarding the crystallinity of acyl chains or the positions of encapsulated species. Here, we demonstrate that a simple five-layer-core-shell discoidal model can be employed to best fit the extended-q small angle X-ray scattering (SAXS) data and resolve the bilayer internal structure (with sub-nanometer resolution) of a nanoscale discoidal system comprised of a mixture of long- and short- chain lipids (known as "bicelles"). In contrast to the traditional core-shell discoidal model, the detailed structure in the hydrophobic core such as the methylene and methyl groups can be distinguished via this model. The refined model is validated by the SAXS data of bicelles whose electron scattering length density of the hydrophobic core is adjusted by the addition of a long-chain lipid with a fluorine-end group. The higher resolution of the bilayer internal structure can be employed to advance our understanding of the interaction and conformation of the membrane and associated molecules, such as membrane-associated proteins and locations of entrapped species in the lipid nanoparticles.
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Affiliation(s)
- Catherine Cheu
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, USA
| | - Lin Yang
- Brookhaven National Laboratory, PO Box 5000, Upton, NY 11973-5000, USA
| | - Mu-Ping Nieh
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, USA; Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, CT 06269, USA; Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269, USA.
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14
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Kafle A, Akamatsu M, Bhadani A, Sakai K, Kaise C, Kaneko T, Sakai H. Phase Behavior of the Bilayers Containing Hydrogenated Soy Lecithin and β-Sitosteryl Sulfate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6025-6032. [PMID: 32393038 DOI: 10.1021/acs.langmuir.0c00472] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The phase behaviors of systems containing saturated phosphatidylcholine (PC) and plant steroids can be important for designing new alternative delivery methods. In our previous studies, we found that even a small amount of β-sitosteryl sulfate (PSO4) significantly affects the phase behavior, hydration properties, and liposomal properties of pure saturated phosphatidylcholines [Kafle, A.; Colloids Surf., B 2018, 161, 59-66; Kafle, A.; J. Oleo Sci. 2018, 67 (12), 1511-1519]. In the current paper, we are reporting the phase behavior of a more complex system consisting of hydrogenated soy lecithin (HLC), which is useful as a carrier in drug delivery systems or in cosmetics, and PSO4. HLC, which is composed of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA), and lysophosphatidylcholine (LPC), demonstrated a versatile phase behavior. The PC component of HLC was found to separate from the PE and PA components as a result of nonideal mixing. At room temperature, these two domains represented two distinct gel phases denoted Lβ1 and Lβ2. The Lβ1 phase selectively underwent transition into the liquid crystalline phase (Lα) at a lower temperature than Lβ2. Upon addition of PSO4, at room temperature, the PC fraction gradually converted into the liquid-ordered (Lo) phase, while the (PE + PA) fraction remained unaffected. When heated above 60 °C, the whole material converted into the liquid crystalline phase. The observed fluidizing effect of PSO4 on HLC can find applications in preparing vehicles for moisture or drugs in cosmetic and pharmaceutical formulations.
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Affiliation(s)
- Ananda Kafle
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
| | - Masaaki Akamatsu
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
| | - Avinash Bhadani
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
| | - Kenichi Sakai
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
| | - Chihiro Kaise
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
- L. V. M. C. Inc., Kamagome-7-14-3, Toshima-ku, Tokyo 170-0003, Japan
| | - Teruhisa Kaneko
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
- L. V. M. C. Inc., Kamagome-7-14-3, Toshima-ku, Tokyo 170-0003, Japan
| | - Hideki Sakai
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
- Research Institute for Science and Technology, Tokyo University of Science, 2641-Yamazaki, Noda, Chiba 278-8510, Japan
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15
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Träger J, Widder K, Kerth A, Harauz G, Hinderberger D. Effect of Cholesterol and Myelin Basic Protein (MBP) Content on Lipid Monolayers Mimicking the Cytoplasmic Membrane of Myelin. Cells 2020; 9:cells9030529. [PMID: 32106542 PMCID: PMC7140459 DOI: 10.3390/cells9030529] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/16/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Myelin basic protein (MBP) is located in the insulating covers of nerve cells in the brain and spinal cord. By interacting with lipid membranes, it is responsible for compaction of the myelin sheath in the central nervous system, which is weakened in demyelinating diseases. The lipid composition of the myelin leaflet has a high impact on the interaction between the membrane and MBP. Cholesterol is present in the cytoplasmic leaflet with a rather high amount of 44% (mol%). In this study, the focus is on the effect of cholesterol, mainly by varying its content, on the interaction of MBP with a lipid monolayer. Therefore, Langmuir lipid monolayers mimicking the cytoplasmic membrane of myelin and monolayers with variations of cholesterol content between 0% and 100% were measured at the air/water interface with additional imaging by fluorescence microscopy. All experiments were performed with and without bovine MBP to study the dependence of the interaction of the protein with the monolayers on the cholesterol content. The native amount of 44% cholesterol in the monolayer combines optima in the order of the monolayer (presumably correlating to compaction and thermodynamic stability) and protein interaction and shows unique features in comparison to lower or higher cholesterol contents.
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Affiliation(s)
- Jennica Träger
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany; (J.T.); (K.W.); (A.K.)
- Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Katharina Widder
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany; (J.T.); (K.W.); (A.K.)
- Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Andreas Kerth
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany; (J.T.); (K.W.); (A.K.)
- Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - George Harauz
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada;
| | - Dariush Hinderberger
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany; (J.T.); (K.W.); (A.K.)
- Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
- Correspondence: ; Tel.: +49-345-55-25230
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16
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Kubyshkin V, Grage SL, Ulrich AS, Budisa N. Bilayer thickness determines the alignment of model polyproline helices in lipid membranes. Phys Chem Chem Phys 2019; 21:22396-22408. [PMID: 31577299 DOI: 10.1039/c9cp02996f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Our understanding of protein folds relies fundamentally on the set of secondary structures found in the proteomes. Yet, there also exist intriguing structures and motifs that are underrepresented in natural biopolymeric systems. One example is the polyproline II helix, which is usually considered to have a polar character and therefore does not form membrane spanning sections of membrane proteins. In our work, we have introduced specially designed polyproline II helices into the hydrophobic membrane milieu and used 19F NMR to monitor the helix alignment in oriented lipid bilayers. Our results show that these artificial hydrophobic peptides can adopt several different alignment states. If the helix is shorter than the thickness of the hydrophobic core of the membrane, it is submerged into the bilayer with its long axis parallel to the membrane plane. The polyproline helix adopts a transmembrane alignment when its length exceeds the bilayer thickness. If the peptide length roughly matches the lipid thickness, a coexistence of both states is observed. We thus show that the lipid thickness plays a determining role in the occurrence of a transmembrane polyproline II helix. We also found that the adaptation of polyproline II helices to hydrophobic mismatch is in some notable aspects different from α-helices. Finally, our results prove that the polyproline II helix is a competent structure for the construction of transmembrane peptide segments, despite the fact that no such motif has ever been reported in natural systems.
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Affiliation(s)
- Vladimir Kubyshkin
- Institute of Chemistry, Technical University of Berlin, Müller-Breslau-Str. 10, Berlin 10623, Germany and Department of Chemistry, University of Manitoba, Dysart Rd. 144, Winnipeg MB R3T 2N2, Canada.
| | - Stephan L Grage
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), P.O.B. 3640, Karlsruhe 76021, Germany
| | - Anne S Ulrich
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), P.O.B. 3640, Karlsruhe 76021, Germany and Institute of Organic Chemistry, KIT, Fritz-Haber-Weg 6, Karlsruhe 76131, Germany
| | - Nediljko Budisa
- Institute of Chemistry, Technical University of Berlin, Müller-Breslau-Str. 10, Berlin 10623, Germany and Department of Chemistry, University of Manitoba, Dysart Rd. 144, Winnipeg MB R3T 2N2, Canada.
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17
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Bui TT, Suga K, Umakoshi H. Ergosterol-Induced Ordered Phase in Ternary Lipid Mixture Systems of Unsaturated and Saturated Phospholipid Membranes. J Phys Chem B 2019; 123:6161-6168. [DOI: 10.1021/acs.jpcb.9b03413] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Tham Thi Bui
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Keishi Suga
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Hiroshi Umakoshi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
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18
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Abstract
Of all the macromolecular assemblies of life, the least understood is the biomembrane. This is especially true in regard to its atomic structure. Ideas on biomembranes, developed in the last 200 years, culminated in the fluid mosaic model of the membrane. In this essay, I provide a historical outline of how we arrived at our current understanding of biomembranes and the models we use to describe them. A selection of direct experimental findings on the nano-scale structure of biomembranes is taken up to discuss their physical nature, and special emphasis is put on the surprising insights that arise from atomic scale descriptions.
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19
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Stability of the two-dimensional lattice of bacteriorhodopsin reconstituted in partially fluorinated phosphatidylcholine bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:631-642. [DOI: 10.1016/j.bbamem.2018.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/27/2018] [Accepted: 12/20/2018] [Indexed: 11/21/2022]
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20
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Effect of Cholesterol on the Dipole Potential of Lipid Membranes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1115:135-154. [DOI: 10.1007/978-3-030-04278-3_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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21
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Fourier-transform infrared and Raman characterization of bilayer membranes of the phospholipid SOPC and its mixtures with cholesterol. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2018.04.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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22
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Shamsuzzaman, Dar AM, Shervani S, Bhat I, Gatoo MA. Structural, optical and antimicrobial studies of 3β-acetoxycholest-5-ene, 3β-acetoxy-6-nitrocholest-5-ene and newly synthesized steroidal pyrazolones. JOURNAL OF TAIBAH UNIVERSITY FOR SCIENCE 2018. [DOI: 10.1016/j.jtusci.2013.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Shamsuzzaman
- Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India
| | - Ayaz M. Dar
- Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India
| | - Suboohi Shervani
- Centre of Excellence in Materials Science (Nanomaterials), Department of Applied Physics, Aligarh Muslim University, Aligarh 202002, India
| | - Irshad Bhat
- Department of Physics, Aligarh Muslim University, Aligarh 202002, India
| | - Manzoor A. Gatoo
- Department of Biochemistry, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh 202002, India
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23
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Gaburjakova J, Gaburjakova M. Reconstitution of Ion Channels in Planar Lipid Bilayers: New Approaches. ADVANCES IN BIOMEMBRANES AND LIPID SELF-ASSEMBLY 2018. [DOI: 10.1016/bs.abl.2017.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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24
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Hung WC, Lee MT, Chung H, Sun YT, Chen H, Charron NE, Huang HW. Comparative Study of the Condensing Effects of Ergosterol and Cholesterol. Biophys J 2017; 110:2026-33. [PMID: 27166810 DOI: 10.1016/j.bpj.2016.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/04/2016] [Accepted: 04/05/2016] [Indexed: 10/21/2022] Open
Abstract
Cholesterol, due to its condensing effect, is considered an important regulator of membrane thickness. Other sterols, due to their structural similarities to cholesterol, are often assumed to have a universal effect on membrane properties similar to the condensing effect of cholesterol, albeit possibly to different degrees. We used x-ray diffraction to investigate this assumption. By the combination of lamellar diffraction and grazing-angle scattering, we measured the membrane thickness and the tilt-angle distribution of the lipid's hydrocarbon chains. This method is sensitive to phase separation, which is important for examining the miscibility of sterols and phospholipids. Mixtures of ergosterol or cholesterol with dimyristoylphosphatidylcholine, palmitoyloleoylphosphatidylcholine, and dioleoylphosphatidylcholine were systematically studied. We found that mixing ergosterol with phospholipids into a single phase became increasingly difficult with higher sterol concentrations and also with higher concentrations of unsaturated lipid chains. The only condensing effect of ergosterol was found in dimyristoylphosphatidylcholine, although the effect was less than one-third of the effect of cholesterol. Unlike cholesterol, ergosterol could not maintain a fixed electron density profile of the surrounding lipids independent of hydration. In dioleoylphosphatidylcholine and palmitoyloleoylphosphatidylcholine, ergosterol made the membranes thinner, opposite to the effect of cholesterol. In all cases, the tilt-angle variation of the chain diffraction was consistent with the membrane thickness changes measured by lamellar diffraction, i.e., a thickening was always associated with a reduction of chain tilt angles. Our findings do not support the notion that different sterols have a universal behavior that differs only in degree.
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Affiliation(s)
- Wei-Chin Hung
- Department of Physics, Republic of China Military Academy, Fengshan, Kaohsiung, Taiwan
| | - Ming-Tao Lee
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan; Department of Physics, National Central University, Jhongli, Taiwan
| | - Hsien Chung
- Department of Physics, Republic of China Military Academy, Fengshan, Kaohsiung, Taiwan
| | - Yi-Ting Sun
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan; Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Hsiung Chen
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | | | - Huey W Huang
- Department of Physics and Astronomy, Rice University, Houston, Texas.
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25
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26
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Ma Y, Ghosh SK, DiLena DA, Bera S, Lurio LB, Parikh AN, Sinha SK. Cholesterol Partition and Condensing Effect in Phase-Separated Ternary Mixture Lipid Multilayers. Biophys J 2016; 110:1355-66. [PMID: 27028645 DOI: 10.1016/j.bpj.2016.02.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 02/05/2016] [Accepted: 02/16/2016] [Indexed: 01/08/2023] Open
Abstract
The cholesterol partitioning and condensing effect in the liquid-ordered (Lo) and liquid-disordered (Ld) phases were systematically investigated for ternary mixture lipid multilayers consisting of 1:1 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phosphocholine with varying concentrations of cholesterol. X-ray lamellar diffraction was used to deduce the electron density profiles of each phase. The cholesterol concentration in each phase was quantified by fitting of the electron density profiles with a newly invented basic lipid profile scaling method that minimizes the number of fitting parameters. The obtained cholesterol concentration in each phase versus total cholesterol concentration in the sample increases linearly for both phases. The condensing effect of cholesterol in ternary lipid mixtures was evaluated in terms of phosphate-to-phosphate distances, which together with the estimated cholesterol concentration in each phase was converted into an average area per molecule. In addition, the cholesterol position was determined to a precision of (±0.7Å) and an increase of disorder in the lipid packing in the Lo phase was observed for total cholesterol concentration of 20∼30%.
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Affiliation(s)
- Yicong Ma
- Department of Physics, University of California-San Diego, La Jolla, California
| | - Sajal K Ghosh
- Department of Physics, University of California-San Diego, La Jolla, California
| | - David A DiLena
- Department of Physics, University of California-San Diego, La Jolla, California
| | - Sambhunath Bera
- Department of Physics, University of California-San Diego, La Jolla, California
| | - Laurence B Lurio
- Department of Physics, Northern Illinois University, DeKalb, Illinois
| | - Atul N Parikh
- Department of Biomedical Engineering and Department of Chemical Engineering and Materials Science, University of California-Davis, Davis, California
| | - Sunil K Sinha
- Department of Physics, University of California-San Diego, La Jolla, California.
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27
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Abstract
Although computer simulation of biological molecules has seen widespread growth and is widely accepted as an important biochemical tool, it is hampered by lim ited computing resources. Biomolecular systems, by necessity, contain a large number of interaction sites. In many cases, these sites interact over quite large dis tances. Further, the time scales of biological interest are long, which requires that simulations of dynamical properties at the atomic level must be lengthy to ade quately probe these motions. We address these issues through discussions of atomic-level molecular dynam ics simulations of biological lipid bilayer membranes, which are key constructs in biochemistry. These simu lations reproduce many experimental observables and provide a degree of resolution currently unavailable experimentally. The lengths of these simulations, the longest of which was 2 nanoseconds, were sufficient to effectively sample many of the motions governing the behavior of biomembranes. Examples are given showing the importance of long-range interactions. The number of interaction sites required by these sim ulations is discussed, particularly the need for explicit representation of solvent molecules.
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Affiliation(s)
- Terry R. Stouch
- BRISTOL-MYERS SQUIBB PHARMACEUTICAL RESEARCH INSTITUTE P.O. BOX 4000 PRINCETON, NJ 08543-4000
| | - Howard E. Alper
- BRISTOL-MYERS SQUIBB PHARMACEUTICAL RESEARCH INSTITUTE P.O. BOX 4000 PRINCETON, NJ 08543-4000
| | - Donna Bassolino-Klimas
- BRISTOL-MYERS SQUIBB PHARMACEUTICAL RESEARCH INSTITUTE P.O. BOX 4000 PRINCETON, NJ 08543-4000
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28
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Selyutina OY, Apanasenko IE, Kim AV, Shelepova EA, Khalikov SS, Polyakov NE. Spectroscopic and molecular dynamics characterization of glycyrrhizin membrane-modifying activity. Colloids Surf B Biointerfaces 2016; 147:459-466. [PMID: 27580071 DOI: 10.1016/j.colsurfb.2016.08.037] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 12/29/2022]
Abstract
Glycyrrhizic acid (GA) is a triterpene glycoside extracted from licorice root. Due to its amphiphilicity GA is capable of forming complexes with a variety of hydrophobic molecules, substantially increasing their solubility. GA can enhance the therapeutic effects of various drugs. It was hypothesized that the increased bioavailability of the drug by GA is not only due to increased solubility, but also to enhancement of drug permeability through cell membranes. In this study the interaction of GA with POPC liposomes and model DOPC, POPC and DPPC bilayers was investigated by NMR with addition of shift reagents and MD simulations. This work helps to better understand the mechanism of enhanced drug bioavailability in the presence of GA. NMR and MD reveal that GA does penetrate into the lipid bilayer. NMR shows that GA changes the mobility of lipids. GA is predominantly located in the outer "half-layer" of the liposome and that the middle of the hydrophobic tails is the preferred location. GA freely passes through the bilayer surface to the inner part bringing a few water molecules. Also both approaches indicate pore formation in the presence of GA. The GA interaction with membranes is an additional aspect of the biological activity of GA-based drug delivery systems.
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Affiliation(s)
- O Yu Selyutina
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090, Novosibirsk, Russia; Novosibirsk State University, Pirogova St., 2, 630090, Novosibirsk, Russia.
| | - I E Apanasenko
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090, Novosibirsk, Russia; Novosibirsk State University, Pirogova St., 2, 630090, Novosibirsk, Russia
| | - A V Kim
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090, Novosibirsk, Russia
| | - E A Shelepova
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090, Novosibirsk, Russia; Novosibirsk State University, Pirogova St., 2, 630090, Novosibirsk, Russia
| | - S S Khalikov
- Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Vavilova St., 28, 119334, Moscow, Russia
| | - N E Polyakov
- Institute of Chemical Kinetics and Combustion, Institutskaya St., 3, 630090, Novosibirsk, Russia
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29
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Yamada A, Shimizu N, Hikima T, Takata M, Kobayashi T, Takahashi H. Effect of Cholesterol on the Interaction of Cytochrome P450 Substrate Drug Chlorzoxazone with the Phosphatidylcholine Bilayer. Biochemistry 2016; 55:3888-98. [DOI: 10.1021/acs.biochem.6b00286] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ayumi Yamada
- Biophysics
Laboratory, Division of Pure and Applied Science, Graduate School
of Science and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma 371-8510, Japan
| | - Nobutaka Shimizu
- Photon
Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Takaaki Hikima
- RIKEN SPring-8 Center, 1-1-1
Kouto, Sayo, Hyougo 679-5148, Japan
| | - Masaki Takata
- RIKEN SPring-8 Center, 1-1-1
Kouto, Sayo, Hyougo 679-5148, Japan
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1
Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Toshihide Kobayashi
- Lipid
Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroshi Takahashi
- Biophysics
Laboratory, Division of Pure and Applied Science, Graduate School
of Science and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma 371-8510, Japan
- RIKEN SPring-8 Center, 1-1-1
Kouto, Sayo, Hyougo 679-5148, Japan
- Lipid
Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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30
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Monajjemi M. Cell membrane causes the lipid bilayers to behave as variable capacitors: A resonance with self-induction of helical proteins. Biophys Chem 2015; 207:114-27. [PMID: 26529673 DOI: 10.1016/j.bpc.2015.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/20/2015] [Accepted: 10/20/2015] [Indexed: 01/10/2023]
Abstract
Cell membrane has a unique feature of storing biological energies in a physiologically relevant environment. This study illustrates a capacitor model of biological cell membrane including DPPC structures. The electron density profile models, electron localization function (ELF) and local information entropy have been applied to study the interaction of proteins with lipid bilayers in the cell membrane. The quantum and coulomb blockade effects of different thicknesses in the membrane have also been specifically investigated. It has been exhibited the quantum effects can appear in a small region of the free space within the membrane thickness due to the number and type of phospholipid layers. In addition, from the viewpoint of quantum effects by Heisenberg rule, it is shown the quantum tunneling is allowed in some micro positions while it is forbidden in other forms of membrane capacitor systems. Due to the dynamical behavior of the cell membrane, its capacitance is not fixed which results a variable capacitor. In presence of the external fields through protein trance membrane or ions, charges exert forces that can influence the state of the cell membrane. This causes to appear the charge capacitive susceptibility that can resonate with self-induction of helical coils; the resonance of which is the main reason for various biological pulses.
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Affiliation(s)
- Majid Monajjemi
- Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran.
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31
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Milles S, Meyer T, Scheidt HA, Schwarzer R, Thomas L, Marek M, Szente L, Bittman R, Herrmann A, Günther Pomorski T, Huster D, Müller P. Organization of fluorescent cholesterol analogs in lipid bilayers — Lessons from cyclodextrin extraction. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1822-8. [DOI: 10.1016/j.bbamem.2013.04.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/15/2013] [Accepted: 04/03/2013] [Indexed: 12/21/2022]
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Pisani M, Mobbili G, Placentino IF, Smorlesi A, Bruni P. Biophysical Characterization of Complexes of DNA with Mixtures of the Neutral Lipids 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine-N-hexanoylamine or 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine-N-dodecanoylamine and 1,2-Dioleoyl-sn-glycero-3-phosphocholine in the Presence of Bivalent Metal Cations for DNA Transfection. J Phys Chem B 2011; 115:10198-206. [DOI: 10.1021/jp202577u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Michela Pisani
- Chemistry Division of the ISAC Department, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Giovanna Mobbili
- Chemistry Division of the ISAC Department, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Immacolata F. Placentino
- Chemistry Division of the ISAC Department, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Arianna Smorlesi
- Department of Pathology and Innovative Therapies, Polytechnic University of Marche, Via Tronto 10/A, 60100 Ancona, Italy
| | - Paolo Bruni
- Chemistry Division of the ISAC Department, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy
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33
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Loura LMS, Ramalho JPP. Recent developments in molecular dynamics simulations of fluorescent membrane probes. Molecules 2011; 16:5437-52. [PMID: 21709624 PMCID: PMC6264736 DOI: 10.3390/molecules16075437] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 06/21/2011] [Accepted: 06/22/2011] [Indexed: 01/25/2023] Open
Abstract
Due to their sensitivity and versatility, the use of fluorescence techniques in membrane biophysics is widespread. Because membrane lipids are non-fluorescent, extrinsic membrane probes are widely used. However, the behaviour of these probes when inserted in the bilayer is often poorly understood, and it can be hard to distinguish between legitimate membrane properties and perturbation resulting from probe incorporation. Atomistic molecular dynamics simulations present a convenient way to address these issues and have been increasingly used in recent years in this context. This article reviews the application of molecular dynamics to the study of fluorescent membrane probes, focusing on recent work with complex design fluorophores and ordered bilayer systems.
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Affiliation(s)
- Luís M. S. Loura
- Faculdade de Farmácia, Universidade de Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal;
- Centro de Química de Coimbra, Universidade de Coimbra, Rua Larga, 3004-535 Coimbra, Portugal
| | - J. P. Prates Ramalho
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, 7002-554 Évora, Portugal
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34
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Alves I, Staneva G, Tessier C, Salgado GF, Nuss P. The interaction of antipsychotic drugs with lipids and subsequent lipid reorganization investigated using biophysical methods. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2009-18. [PMID: 21377444 DOI: 10.1016/j.bbamem.2011.02.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 02/24/2011] [Accepted: 02/25/2011] [Indexed: 11/30/2022]
Abstract
The interaction of antipsychotic drugs (AP) with lipids and the subsequent lipid reorganization on model membranes was assessed using a combination of several complementary biophysical approaches (calorimetry, plasmon resonance, fluorescence microscopy, X-ray diffraction and molecular modeling). The effect of haloperidol (HAL), risperidone (RIS), and 9-OH-risperidone (9-OH-RIS) was examined on single lipid and mixtures comprising lipids of biological origin. All APs interact with lipids and induced membrane reorganization. APs showed higher affinity for sphingomyelin than for phosphatidylcholine. Cholesterol increased AP affinity for the lipid bilayer and led to the following AP ranking regarding affinity and structural changes: RIS >9-OH-RIS >HAL. Liquid-ordered domain formation and bilayer thickness were differentially altered by AP addition. Docking calculations helped understanding the observed differences between the APs and offer a representation of their conformation in the lipid bilayer. Present results indicate that AP drugs may change membrane compartmentalization which could differentially modulate the signaling cascade of the dopamine D2 receptor for which APs are ligands.
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Affiliation(s)
- Isabel Alves
- Université Pierre et Marie Curie-Paris 6, UMRS 7203 CNRS-ENS, Laboratoire des BioMolécules, 4, place Jussieu, 75252 Paris cedex 05, France
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35
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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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36
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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: 151] [Impact Index Per Article: 10.8] [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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37
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New insights into the stratum corneum lipid organization by X-ray diffraction analysis. Biophys J 2010; 97:2242-9. [PMID: 19843456 DOI: 10.1016/j.bpj.2009.07.040] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 07/20/2009] [Accepted: 07/21/2009] [Indexed: 11/23/2022] Open
Abstract
The characteristic 13-nm lamellar phase that is formed by lipids in the outermost layer of the skin, the stratum corneum (SC), is very important for the barrier function of the skin. To gain more insight into the molecular organization of this lamellar phase, we performed small-angle x-ray diffraction (SAXD) using various lipid mixtures mimicking the lipid composition in SC. In the SAXD pattern of each mixture, at least seven diffraction orders were observed, attributed to the lamellar phase with a repeat distance ranging from 12.1 to 13.8 nm. Using the sampling method based on the variation in repeat distance, we selected phase angles for the first six diffraction orders. Using these phase angles for the lamellar phase, a high-resolution electron density distribution could be calculated. Subsequently, from SAXD patterns of isolated SC, the electron density distribution of the lamellar phase was also calculated and appeared to be very similar to that in the lipid mixtures. This demonstrates that the lipid mixtures serve as an excellent model for the lipid organization in SC, not only with respect to the repeat distance, but also in terms of the electron density distribution within the unit cell.
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38
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X-ray and Neutron Scattering Studies of Lipid–Sterol Model Membranes. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1554-4516(10)11008-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
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39
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Evidence of free fatty acid interdigitation in stratum corneum model membranes based on ceramide [AP] by deuterium labelling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2194-203. [DOI: 10.1016/j.bbamem.2009.07.024] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 07/24/2009] [Accepted: 07/28/2009] [Indexed: 11/30/2022]
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40
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Akita H. Recent Advances in the use of Immobilized Lipases Directed Toward the Asymmetric Syntheses of Complex Molecules. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.3109/10242429608997671] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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41
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Milani S, Berti D, Dante S, Hauss T, Baglioni P. Intercalation of single-strand oligonucleotides between nucleolipid anionic membranes: a neutron diffraction study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:4084-4092. [PMID: 19714893 DOI: 10.1021/la8029825] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This contribution presents a neutron diffraction investigation of anionic lamellar phases composed of mixtures of 1-palmitoyl, 2-oleoyl phosphatidyl-nucleosides (POPN, where N is either adenosine or uridine), and POPC (1-palmitoyl,2-oleoyl-phosphatidyl-choline). Their behavior is studied for two different mole ratios and in the presence of nucleic acids. The samples are formed by the evaporation of liposomal dispersions prepared in water or in solutions containing single-strand oligonucleotides. Previous small angle X-ray scattering (SAXS) experiments on the system POPA/polyU (polyuridylic acid, high degree of polymerization, synthetic ribonucleic acid) proved that the insertion and ordering of the biopolymer in the phospholipid lamellae were driven by molecular recognition. In the present study, we extend the previous investigation to single-strand monodisperse oligonucleotides (50-mers). Structural details of the membranes were obtained from the analysis of the neutron diffraction scattering length density profiles. The evidence of direct and specific interactions, driven by molecular recognition between the nucleic polar heads of the nucleolipid and the single-strand nucleic acid, is strengthened by the comparison with identically charged bilayers formed by POPG/POPC. These results contribute to the understanding of the parameters governing the interactions between nucleolipid membranes and oligonucleotides, providing a novel strategy for the design of lipid-based vehicles for nucleic acids.
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Affiliation(s)
- Silvia Milani
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3-Sesto Fiorentino, 50019 Florence, Italy
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42
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Sanyal SN, Sood N, Kaushal N. Alterations in the Lipid Profile and Membrane Dynamics of Rat Intestinal Brush Border Membrane Induced by Different Classes of Nonsteroidal Anti-Inflammatory Drugs. Toxicol Mech Methods 2008; 17:49-56. [DOI: 10.1080/15376510600812624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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43
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Harroun TA, Katsaras J, Wassall SR. Cholesterol Is Found To Reside in the Center of a Polyunsaturated Lipid Membrane. Biochemistry 2008; 47:7090-6. [DOI: 10.1021/bi800123b] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thad A. Harroun
- Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada, Canadian Neutron Beam Centre, National Research Council, Chalk River, Ontario K0J 1J0, Canada, Guelph-Waterloo Physics Institute and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada, and Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202-3273
| | - John Katsaras
- Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada, Canadian Neutron Beam Centre, National Research Council, Chalk River, Ontario K0J 1J0, Canada, Guelph-Waterloo Physics Institute and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada, and Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202-3273
| | - Stephen R. Wassall
- Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada, Canadian Neutron Beam Centre, National Research Council, Chalk River, Ontario K0J 1J0, Canada, Guelph-Waterloo Physics Institute and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada, and Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202-3273
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44
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The effect of cholesterol on short- and long-chain monounsaturated lipid bilayers as determined by molecular dynamics simulations and X-ray scattering. Biophys J 2008; 95:2792-805. [PMID: 18515383 DOI: 10.1529/biophysj.107.122465] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We investigate the structure of cholesterol-containing membranes composed of either short-chain (diC14:1PC) or long-chain (diC22:1PC) monounsaturated phospholipids. Bilayer structural information is derived from all-atom molecular dynamics simulations, which are validated via direct comparison to x-ray scattering experiments. We show that the addition of 40 mol % cholesterol results in a nearly identical increase in the thickness of the two different bilayers. In both cases, the chain ordering dominates over the hydrophobic matching between the length of the cholesterol molecule and the hydrocarbon thickness of the bilayer, which one would expect to cause a thinning of the diC22:1PC bilayer. For both bilayers there is substantial headgroup rearrangement for lipids directly in contact with cholesterol, supporting the so-called umbrella model. Importantly, in diC14:1PC bilayers, a dynamic network of hydrogen bonds stabilizes long-lived reorientations of some cholesterol molecules, during which they are found to lie perpendicular to the bilayer normal, deep within the bilayer's hydrophobic core. Additionally, the simulations show that the diC14:1PC bilayer is significantly more permeable to water. These differences may be correlated with faster cholesterol flip-flop between the leaflets of short-chain lipid bilayers, resulting in an asymmetric distribution of cholesterol molecules. This asymmetry was observed experimentally in a case of unilamellar vesicles (ULVs), and reproduced through a set of novel asymmetric simulations. In contrast to ULVs, experimental data for oriented multilamellar stacks does not show the asymmetry, suggesting that it results from the curvature of the ULV bilayers.
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45
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Wartewig S, Neubert RHH. Properties of Ceramides and Their Impact on the Stratum Corneum Structure: A Review. Skin Pharmacol Physiol 2007; 20:220-9. [PMID: 17587886 DOI: 10.1159/000104420] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 04/27/2007] [Indexed: 11/19/2022]
Abstract
The lipid matrix of the stratum corneum (SC) is the major diffusion-rate-limiting pathway by which most drugs intracellularly pass the SC. The major lipid classes extracted from the SC are ceramides, cholesterol and free fatty acids. Ceramides that comprise nine subclasses play a crucial role in maintaining the barrier function of the skin. A profound knowledge of the physical properties of ceramides is essential for a deeper understanding of the impact of each ceramide species on the barrier function. The review summarizes the thermotropic and/or lyotropic behaviour of sphingosine-type ceramides (CER AS, CER NS) and phytosphingosine-type ceramides (CER AP, CER NP) revealed by differential scanning calorimetry, X-ray diffraction, Fourier transform infrared spectroscopy and Fourier transform Raman spectroscopy in past decades. Polymorphism is a characteristic feature of ceramides. At physiological temperatures, all crystalline phases of ceramides exhibit lamellar structures with highly ordered hydrocarbon chains. The differential behaviour of the head groups of ceramides may be an important determinant for the skin barrier function.
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Affiliation(s)
- S Wartewig
- Institute of Applied Dermatopharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
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46
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Schnitzer E, Pinchuk I, Lichtenberg D. Peroxidation of liposomal lipids. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:499-515. [PMID: 17380326 DOI: 10.1007/s00249-007-0146-2] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2006] [Revised: 02/20/2007] [Accepted: 02/22/2007] [Indexed: 11/30/2022]
Abstract
Free radicals, formed via different mechanisms, induce peroxidation of membrane lipids. This process is of great importance because it modifies the physical properties of the membranes, including its permeability to different solutes and the packing of lipids and proteins in the membranes, which in turn, influences the membranes' function. Accordingly, much research effort has been devoted to the understanding of the factors that govern peroxidation, including the composition and properties of the membranes and the inducer of peroxidation. In view of the complexity of biological membranes, much work was devoted to the latter issues in simplified model systems, mostly lipid vesicles (liposomes). Although peroxidation in model membranes may be very different from peroxidation in biological membranes, the results obtained in model membranes may be used to advance our understanding of issues that cannot be studied in biological membranes. Nonetheless, in spite of the relative simplicity of peroxidation of liposomal lipids, these reactions are still quite complex because they depend in a complex fashion on both the inducer of peroxidation and the composition and physical properties of the liposomes. This complexity is the most likely cause of the apparent contradictions of literature results. The main conclusion of this review is that most, if not all, of the published results (sometimes apparently contradictory) on the peroxidation of liposomal lipids can be understood on the basis of the physico-chemical properties of the liposomes. Specifically: (1) The kinetics of peroxidation induced by an "external" generator of free radicals (e.g. AAPH) is governed by the balance between the effects of membrane properties on the rate constants of propagation (k (p)) and termination (k (t)) of the free radical peroxidation in the relevant membrane domains, i.e. in those domains in which the oxidizable lipids reside. Both these rate constants depend similarly on the packing of lipids in the bilayer, but influence the overall rate in opposite directions. (2) Peroxidation induced by transition metal ions depends on additional factors, including the binding of metal ions to the lipid-water interface and the formation of a metal ions-hydroperoxide complex at the surface. (3) Reducing agents, commonly regarded as "antioxidants", may either promote or inhibit peroxidation, depending on the membrane composition, the inducer of oxidation and the membrane/water partitioning. All the published data can be explained in terms of these (quite complex) generalizations. More detailed analysis requires additional experimental investigations.
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Affiliation(s)
- Edit Schnitzer
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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47
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Abstract
The condensing effect of cholesterol on phospholipid bilayers was systematically investigated for saturated and unsaturated chains, as a function of cholesterol concentration. X-ray lamellar diffraction was used to measure the phosphate-to-phosphate distances, PtP, across the bilayers. The measured PtP increases nonlinearly with the cholesterol concentration until it reaches a maximum. With further increase of cholesterol concentration, the PtP remains at the maximum level until the cholesterol content reaches the solubility limit. The data in all cases can be quantitatively explained with a simple model that cholesterol forms complexes with phospholipids in the bilayers. The phospholipid molecules complexed with cholesterol are lengthened and this lengthening effect extends into the uncomplexed phospholipids surrounding the cholesterol complexes. This long-range thickening effect is similar to the effect of gramicidin on the thickness of lipid bilayers due to hydrophobic matching.
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Affiliation(s)
- Wei-Chin Hung
- Department of Physics, Chinese Military Academy, Fengshan, Kaohsiung, Taiwan
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48
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Mavromoustakos TM. The use of differential scanning calorimetry to study drug-membrane interactions. Methods Mol Biol 2007; 400:587-600. [PMID: 17951761 DOI: 10.1007/978-1-59745-519-0_39] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Differential-scanning calorimetry is a thermodynamic technique widely used for studying drug-membrane interactions. This chapter provides practical examples on this topic, highlighting the caution to be taken in analyzing thermal data as well as scientific information that can be derived by the proper use of the technique. An example is given using model bilayers containing high concentration of the anesthetic steroid alphaxalone. It is shown that the breadth of the phase transitions and the maximum of the phase-transition temperature of the bilayer depend on the equilibration conditions before acquiring the thermal scan. In addition, the quality of the thermo-gram depends on its perturbation and incorporation effects; for dissecting these effects, a complementary technique such as solid-state nuclear magnetic resonance spectroscopy is necessary. Differential-scanning calorimetry is a useful technique to study the interdigitation effect of a drug by monitoring DeltaH changes. Cholesterol, a main constituent of membrane bilayers, appears to disrupt the interdigitating effect. In general, the thermal effects of the drug incorporated into a membrane bilayer depends on the drug stereoelectronic properties.
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Affiliation(s)
- Thomas M Mavromoustakos
- Institute of Organic and Pharmaceutical Chemistry, National Hellenic Research Foundation, Athens, Greece
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49
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Starke-Peterkovic T, Turner N, Vitha MF, Waller MP, Hibbs DE, Clarke RJ. Cholesterol effect on the dipole potential of lipid membranes. Biophys J 2006; 90:4060-70. [PMID: 16513788 PMCID: PMC1459515 DOI: 10.1529/biophysj.105.074666] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Accepted: 01/18/2006] [Indexed: 01/05/2023] Open
Abstract
The effect of cholesterol removal by methyl-beta-cyclodextrin on the dipole potential, psi(d), of membrane vesicles composed of natural membrane lipids extracted from the kidney and brain of eight vertebrate species was investigated using the voltage-sensitive fluorescent probe di-8-ANEPPS. Cyclodextrin treatment reduced cholesterol levels by on average 80% and this was associated with an average reduction in psi(d) of 50 mV. Measurements of the effect of a range of cholesterol derivatives on the psi(d) of DMPC lipid vesicles showed that the magnitude of the effect correlated with the component of the sterol's dipole moment perpendicular to the membrane surface. The changes in psi(d) observed could not be accounted for solely by the electric field originating from the sterols' dipole moments. Additional factors must arise from sterol-induced changes in lipid packing, which changes the density of dipoles in the membrane, and changes in water penetration into the membrane, which changes the effective dielectric constant of the interfacial region. In DMPC membranes, the cholesterol-induced change in psi(d) was biphasic, i.e., a maximum in psi(d) was observed at approximately 35-45 mol %, after which psi(d) started to decrease. We suggest that this could be associated with a maximum in the strength of DMPC-cholesterol intermolecular forces at this composition.
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Affiliation(s)
- Thomas Starke-Peterkovic
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia; Department of Biomedical Science, University of Wollongong, Wollongong NSW 2522, Australia; and Department of Chemistry, Drake University, Des Moines, Iowa 50311
| | - Nigel Turner
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia; Department of Biomedical Science, University of Wollongong, Wollongong NSW 2522, Australia; and Department of Chemistry, Drake University, Des Moines, Iowa 50311
| | - Mark F. Vitha
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia; Department of Biomedical Science, University of Wollongong, Wollongong NSW 2522, Australia; and Department of Chemistry, Drake University, Des Moines, Iowa 50311
| | - Mark P. Waller
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia; Department of Biomedical Science, University of Wollongong, Wollongong NSW 2522, Australia; and Department of Chemistry, Drake University, Des Moines, Iowa 50311
| | - David E. Hibbs
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia; Department of Biomedical Science, University of Wollongong, Wollongong NSW 2522, Australia; and Department of Chemistry, Drake University, Des Moines, Iowa 50311
| | - Ronald J. Clarke
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia; Department of Biomedical Science, University of Wollongong, Wollongong NSW 2522, Australia; and Department of Chemistry, Drake University, Des Moines, Iowa 50311
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50
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Jacob RF, Mason RP. Lipid Peroxidation Induces Cholesterol Domain Formation in Model Membranes. J Biol Chem 2005; 280:39380-7. [PMID: 16195227 DOI: 10.1074/jbc.m507587200] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Numerous reports have established that lipid peroxidation contributes to cell injury by altering the basic physical properties and structural organization of membrane components. Oxidative modification of polyunsaturated phospholipids has been shown, in particular, to alter the intermolecular packing, thermodynamic, and phase parameters of the membrane bilayer. In this study, the effects of oxidative stress on membrane phospholipid and sterol organization were measured using small angle x-ray diffraction approaches. Model membranes enriched in dilinoleoylphosphatidylcholine were prepared at various concentrations of cholesterol and subjected to lipid peroxidation at physiologic conditions. At cholesterol-to-phospholipid mole ratios (C/P) as low as 0.4, lipid peroxidation induced the formation of discrete, membrane-restricted cholesterol domains having a unit cell periodicity or d-space value of 34 A. The formation of cholesterol domains correlated directly with lipid hydroperoxide levels and was inhibited by treatment with vitamin E. In the absence of oxidative stress, similar cholesterol domains were observed only at C/P ratios of 1.0 or higher. In addition to changes in sterol organization, lipid peroxidation also caused reproducible changes in overall membrane structure, including a 10 A reduction in the width of the surrounding, sterol-poor membrane bilayer. These data provided direct evidence that lipid peroxidation alters the essential organization and structure of membrane lipids in a manner that may contribute to changes in membrane function during aging and oxidative stress-related disorders.
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Affiliation(s)
- Robert F Jacob
- Elucida Research, Beverly, Massachusetts 01915-0091, USA.
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