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Rai R, Kumar D, Dhule AA, Rudani BA, Tiwari S. Alkanols Regulate the Fluidity of Phospholipid Bilayer in Accordance to Their Concentration and Polarity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:14057-14065. [PMID: 38935825 DOI: 10.1021/acs.langmuir.4c01499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
In spite of the widespread use of alkanols as penetration enhancers, their effect on vesicular formulations remains largely unexplored. These can affect the stability and integrity of the phospholipid bilayers. In this study, we have investigated the interaction of linear (ethanol, butanol, hexanol, octanol) and branched alkanols (t-amylol and t-butanol) with three phospholipids (soya lecithin, SL; soy L-α-phosphatidylcholine, SPC; and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC). Thermodynamic and structural aspects of these interactions were studied as a function of the alkanol concentration and chain length. Our interpretations are based on isothermal titration calorimetry (ITC) and dynamic light scattering (DLS) experiments. We observed one-site interactions wherein hydroxyl and acyl groups interacted with the polar and nonpolar regions of the phospholipid, respectively. The stability and structural integrity of bilayers appeared to be dependent upon (a) the hydrocarbon chain length and concentration of alcohols, and (b) the degree of unsaturation in the phospholipid molecule. We found that these interactions triggered a reduction in the enthalpy which was compensated by increased entropy, keeping free energy negative. Drop in enthalpy indicates reversible disordering of the bilayer which enables the diffusion of alcohol without triggering destabilization. Ethanol engaged predominantly with the interface, and it resulted in higher enthalpic changes. Interactions became increasingly unfavorable with longer alcohols - a cutoff point was recorded with hexanol. The overall sequence of membrane disordering capability was recorded as follows: ethanol < butanol < octanol < hexanol. Octanol's larger size restricted its penetration in the bilayer, and hence it caused less enthalpic changes relative to hexanol. This could also be verified from the trends in the area ratio of these vesicles obtained from the DLS data. Branched alkanols displayed a lower binding affinity with the phospholipids relative to their linear counterparts. These data are useful while contemplating the inclusion of short-chain alcohols as penetration enhancers in phospholipid vesicles.
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Affiliation(s)
- Ragini Rai
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER) - Raebareli, Lucknow 226002, Uttar Pradesh, India
| | - Deepak Kumar
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER) - Raebareli, Lucknow 226002, Uttar Pradesh, India
| | - Anjali A Dhule
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER) - Raebareli, Lucknow 226002, Uttar Pradesh, India
| | - Binny A Rudani
- IBI-4: Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - Sanjay Tiwari
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER) - Raebareli, Lucknow 226002, Uttar Pradesh, India
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Minkara MS, Josephson TR, Venteicher CL, Greenvall BR, Lindsey RK, Koenig PH, Siepmann JI. Nonane and Hexanol Adsorption in the Lamellar Phase of a Nonionic Surfactant: Molecular Simulations and Comparison to Ideal Adsorbed Solution Theory. J Phys Chem B 2022; 126:3940-3949. [PMID: 35594369 DOI: 10.1021/acs.jpcb.2c02871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Adsorption of n-nonane/1-hexanol (C9/C6OH) mixtures into the lamellar phase formed by a 50/50 w/w triethylene glycol mono-n-decyl ether (C10E3)/water system was studied using configurational-bias Monte Carlo simulations in the osmotic Gibbs ensemble. The interactions were described by the Shinoda-Devane-Klein coarse-grained force field. Prior simulations probing single-component adsorption indicated that C9 molecules preferentially load near the center of the bilayer, increasing the bilayer thickness, whereas C6OH molecules are more likely to be found near the interface of the polar and nonpolar moieties, swelling the bilayer in the lateral dimension. Here, we extend this work to binary C9/C6OH adsorption to probe whether the difference in the spatial preferences may lead to a synergistic effect and enhanced loadings for the mixture. Comparing loading trends and the thermodynamics of binary adsorption to unary adsorption reveals that C9-C9 interactions lead to the largest enhancement, whereas C9-C6OH and C6OH-C6OH interactions are less favorable for this bilayer system. Ideal adsorbed solution theory yields satisfactory predictions of the binary loading.
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Affiliation(s)
- Mona S Minkara
- Department of Bioengineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States.,Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Tyler R Josephson
- Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States.,Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, United States
| | - Connor L Venteicher
- Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Benjamin R Greenvall
- Department of Bioengineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Rebecca K Lindsey
- Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Peter H Koenig
- Computational Chemistry, Modeling and Simulation, The Procter and Gamble Company, 8256 Union Centre Blvd, West Chester, Ohio 45069, United States
| | - J Ilja Siepmann
- Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States.,Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, United States
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3
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Catalytic Conversion of Lipophilic Substrates by Phase constrained Enzymes in the Aqueous or in the Membrane Phase. Sci Rep 2016; 6:38316. [PMID: 27917951 PMCID: PMC5137027 DOI: 10.1038/srep38316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 11/07/2016] [Indexed: 01/20/2023] Open
Abstract
Both soluble and membrane-bound enzymes can catalyze the conversion of lipophilic substrates. The precise substrate access path, with regard to phase, has however, until now relied on conjecture from enzyme structural data only (certainly giving credible and valuable hypotheses). Alternative methods have been missing. To obtain the first experimental evidence directly determining the access paths (of lipophilic substrates) to phase constrained enzymes we here describe the application of a BODIPY-derived substrate (PS1). Using this tool, which is not accessible to cytosolic enzymes in the presence of detergent and, by contrast, not accessible to membrane embedded enzymes in the absence of detergent, we demonstrate that cytosolic and microsomal glutathione transferases (GSTs), both catalyzing the activation of PS1, do so only within their respective phases. This approach can serve as a guideline to experimentally validate substrate access paths, a fundamental property of phase restricted enzymes. Examples of other enzyme classes with members in both phases are xenobiotic-metabolizing sulphotransferases/UDP-glucuronosyl transferases or epoxide hydrolases. Since specific GSTs have been suggested to contribute to tumor drug resistance, PS1 can also be utilized as a tool to discriminate between phase constrained members of these enzymes by analyzing samples in the absence and presence of Triton X-100.
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4
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Gallo V, Stano P, Luisi PL. Protein Synthesis in Sub-Micrometer Water-in-Oil Droplets. Chembiochem 2016; 16:2073-9. [PMID: 26376303 DOI: 10.1002/cbic.201500274] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Indexed: 11/07/2022]
Abstract
Water-in-oil (w/o) emulsions are used as a cellular model because of their unique cell-like architecture. Previous works showed the capability of eukaryotic-cell-sized w/o droplets (5-50 μm) to support protein synthesis efficiently; however data about smaller w/o compartments (<1 μm) are lacking. This work focuses on the biosynthesis of the enhanced green fluorescent protein (EGFP) inside sub-micrometric lecithin-based w/o droplets (0.8-1 μm) and on its dependence on the compartments' dynamic properties in terms of solute exchange mechanisms. We demonstrated that protein synthesis is strongly affected by the nature of the lipid interface. These findings could be of value and interest for both basic and applied research.
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Affiliation(s)
- Valentina Gallo
- Science Department, Roma Tre University, Viale Guglielmo Marconi 446, 00146, Rome, Italy
| | - Pasquale Stano
- Science Department, Roma Tre University, Viale Guglielmo Marconi 446, 00146, Rome, Italy
| | - Pier Luigi Luisi
- Science Department, Roma Tre University, Viale Guglielmo Marconi 446, 00146, Rome, Italy.
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Roy A, Dutta R, Kundu N, Banik D, Sarkar N. A Comparative Study of the Influence of Sugars Sucrose, Trehalose, and Maltose on the Hydration and Diffusion of DMPC Lipid Bilayer at Complete Hydration: Investigation of Structural and Spectroscopic Aspect of Lipid-Sugar Interaction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5124-5134. [PMID: 27133799 DOI: 10.1021/acs.langmuir.6b01115] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
It is well-known that sugars protect membrane structures against fusion and leakage. Here, we have investigated the interaction between different sugars (sucrose, trehalose, and maltose) and phospholipid membrane of 1,2-dimyristoyl-sn-glycero-3-phoshpocholine (DMPC) using dynamic light scattering (DLS), transmission electron microscopy (TEM), and other various spectroscopic techniques. DLS measurement reveals that the addition of sugar molecule results a significant increase of the average diameter of DMPC membrane. We have also noticed that in the presence of different sugars the rotational relaxation and solvation time of coumarin 480 (C480) and coumarin 153 (C153) surrounding DMPC membrane increases, suggesting a marked reduction of the hydration behavior at the surface of phospholipid membrane. In addition, we have also investigated the effect of sugar molecules on the lateral mobility of phospholipids. Interestingly, the relative increase in rotational, solvation and lateral diffusion is more prominent for C480 than that of C153 because of their different location in lipid bilayer. It is because of preferential location of comparatively hydrophilic probe C480 in the interfacial region of the lipid bilayer. Sugars intercalate with the phospholipid headgroup through hydrogen bonding and replace smaller sized water molecules from the membrane surface. Therefore, overall, we have monitored a comparative analysis regarding the interaction of different sugar molecules (sucrose, trehalose, and maltose) with the DMPC membrane through DLS, TEM, solvation dynamics, time-resolved anisotropy, and fluorescence correlation spectroscopy (FCS) measurements to explore the structural and spectroscopic aspect of lipid-sugar interaction.
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Affiliation(s)
- Arpita Roy
- Department of Chemistry, Indian Institute of Technology , Kharagpur 721302, WB, India
| | - Rupam Dutta
- Department of Chemistry, Indian Institute of Technology , Kharagpur 721302, WB, India
| | - Niloy Kundu
- Department of Chemistry, Indian Institute of Technology , Kharagpur 721302, WB, India
| | - Debasis Banik
- Department of Chemistry, Indian Institute of Technology , Kharagpur 721302, WB, India
| | - Nilmoni Sarkar
- Department of Chemistry, Indian Institute of Technology , Kharagpur 721302, WB, India
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6
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Lyubartsev AP, Rabinovich AL. Force Field Development for Lipid Membrane Simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2483-2497. [PMID: 26766518 DOI: 10.1016/j.bbamem.2015.12.033] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/21/2015] [Accepted: 12/23/2015] [Indexed: 02/04/2023]
Abstract
With the rapid development of computer power and wide availability of modelling software computer simulations of realistic models of lipid membranes, including their interactions with various molecular species, polypeptides and membrane proteins have become feasible for many research groups. The crucial issue of the reliability of such simulations is the quality of the force field, and many efforts, especially in the latest several years, have been devoted to parametrization and optimization of the force fields for biomembrane modelling. In this review, we give account of the recent development in this area, covering different classes of force fields, principles of the force field parametrization, comparison of the force fields, and their experimental validation. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Alexander P Lyubartsev
- Department of Materials and Environmental Chemistry, Stockholm University, SE 106 91, Stockholm, Sweden.
| | - Alexander L Rabinovich
- Institute of Biology, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya 11, Petrozavodsk, 185910, Russian Federation.
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7
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Zapata-Morin PA, Sierra-Valdez FJ, Ruiz-Suárez JC. The interaction of local anesthetics with lipid membranes. J Mol Graph Model 2014; 53:200-205. [PMID: 25181454 DOI: 10.1016/j.jmgm.2014.08.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 08/11/2014] [Accepted: 08/12/2014] [Indexed: 11/28/2022]
Abstract
Molecular Dynamic Simulations are performed to evaluate the interaction of lidocaine, procaine and tetracaine with a lipid membrane. The main interest is to evaluate the structural changes produced by these local anesthetics in the bilayers. Penetration trajectories, interaction energies, entropy changes and an order parameter are calculated to quantify the destabilization of the lipid configurations. We show that such structural parameters give important information to understand how anesthetic agents influence the structure of plasma membranes. Graphic processing units (GPUs) are used in our simulations.
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8
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Holmstrup M, Bouvrais H, Westh P, Wang C, Slotsbo S, Waagner D, Enggrob K, Ipsen JH. Lipophilic contaminants influence cold tolerance of invertebrates through changes in cell membrane fluidity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:9797-9803. [PMID: 25050459 DOI: 10.1021/es502221g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Contaminants taken up by living organisms in the environment as a result of anthropogenic contamination can reduce the tolerance of natural stressors, e.g., low temperatures, but the physiological mechanisms behind these interactions of effects are poorly understood. The tolerance to low temperatures of organisms that cannot regulate their body temperature (ectotherms) depends on their ability to increase the fluidity of their cellular membranes at low temperatures. Our study shows that contaminants accumulating in lipids of organisms alter the physical state of their membranes simply by being present. Contaminants of varying chemical structures can alter the membrane fluidity in either direction and correspondingly modulate the cold tolerance of intact animals.
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Affiliation(s)
- Martin Holmstrup
- Department of Bioscience, Aarhus University , Vejlsøvej 25, DK-8600 Silkeborg, Denmark
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9
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Kulschewski T, Pleiss J. A molecular dynamics study of liquid aliphatic alcohols: simulation of density and self-diffusion coefficient using a modified OPLS force field. MOLECULAR SIMULATION 2013. [DOI: 10.1080/08927022.2013.769680] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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10
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Rabinovich AL, Lyubartsev AP. Computer simulation of lipid membranes: Methodology and achievements. POLYMER SCIENCE SERIES C 2013. [DOI: 10.1134/s1811238213070060] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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11
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Peters GH, Wang C, Cruys-Bagger N, Velardez GF, Madsen JJ, Westh P. Binding of serotonin to lipid membranes. J Am Chem Soc 2013; 135:2164-71. [PMID: 23311719 DOI: 10.1021/ja306681d] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) is a prevalent neurotransmitter throughout the animal kingdom. It exerts its effect through the specific binding to the serotonin receptor, but recent research has suggested that neural transmission may also be affected by its nonspecific interactions with the lipid matrix of the synaptic membrane. However, membrane-5-HT interactions remain controversial and superficially investigated. Fundamental knowledge of this interaction appears vital in discussions of putative roles of 5-HT, and we have addressed this by thermodynamic measurements and molecular dynamics (MD) simulations. 5-HT was found to interact strongly with lipid bilayers (partitioning coefficient ~1200 in mole fraction units), and this is highly unusual for a hydrophilic solute like 5-HT which has a bulk, oil-water partitioning coefficient well below unity. It follows that membrane affinity must rely on specific interactions, and the MD simulations identified the salt-bridge between the primary amine of 5-HT and the lipid phosphate group as the most important interaction. This interaction anchored cationic 5-HT in the membrane interface with the aromatic ring system pointing inward and a prevailing residence between the phosphate and the carbonyl groups of the lipid. The unprotonated form of 5-HT shows the opposite orientation, with the primary amine pointing toward the membrane core. Partitioning of 5-HT was found to decrease lipid chain order. These distinctive interactions of 5-HT and model membranes could be related to nonspecific effects of this neurotransmitter.
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Affiliation(s)
- Günther H Peters
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
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12
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Abstract
It is well established that small sugars exert different types of stabilization of biomembranes both in vivo and in vitro. However, the essential question of whether sugars are bound to or expelled from membrane surfaces, i.e., the sign and size of the free energy of the interaction, remains unresolved, and this prevents a molecular understanding of the stabilizing mechanism. We have used small-angle neutron scattering and thermodynamic measurements to show that sugars may be either bound or expelled depending on the concentration of sugar. At low concentration, small sugars bind quite strongly to a lipid bilayer, and the accumulation of sugar at the interface makes the membrane thinner and laterally expanded. Above ∼0.2 M the sugars gradually become expelled from the membrane surface, and this repulsive mode of interaction counteracts membrane thinning. The dual nature of sugar-membrane interactions offers a reconciliation of conflicting views in earlier reports on sugar-induced modulations of membrane properties.
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13
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Mojumdar EH, Lyubartsev AP. Molecular dynamics simulations of local anesthetic articaine in a lipid bilayer. Biophys Chem 2010; 153:27-35. [DOI: 10.1016/j.bpc.2010.10.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 09/30/2010] [Accepted: 10/03/2010] [Indexed: 10/24/2022]
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14
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Klacsová M, Westh P, Balgavý P. Molecular and component volumes of saturated n-alkanols in DOPC+DOPS bilayers. Chem Phys Lipids 2010; 163:498-505. [DOI: 10.1016/j.chemphyslip.2010.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 04/07/2010] [Accepted: 04/08/2010] [Indexed: 10/19/2022]
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15
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Pedersen UR, Peters GH, Schrøder TB, Dyre JC. Correlated volume-energy fluctuations of phospholipid membranes: a simulation study. J Phys Chem B 2010; 114:2124-30. [PMID: 20095587 PMCID: PMC2820308 DOI: 10.1021/jp9086865] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper reports all-atom computer simulations of five phospholipid membranes (DMPC, DPPC, DMPG, DMPS, and DMPSH) with focus on the thermal equilibrium fluctuations of volume, energy, area, thickness, and chain order. At constant temperature and pressure, volume and energy exhibit strong correlations of their slow fluctuations (defined by averaging over 0.5 ns). These quantities, on the other hand, do not correlate significantly with area, thickness, or chain order. The correlations are mainly reported for the fluid phase, but we also give some results for the ordered (gel) phase of two membranes, showing a similar picture. The cause of the observed strong correlations is identified by splitting volume and energy into contributions from tails, heads, and water, and showing that the slow volume-energy fluctuations derive from van der Waals interactions of the tail region; they are thus analogous to the similar strong correlations recently observed in computer simulations of the Lennard-Jones and other simple van der Waals type liquids (U. R. Pedersen et al., Phys. Rev. Lett. 2008, 100, 015701). The strong correlations reported here confirm one crucial assumption of a recent theory for nerve signal propagation proposed by Heimburg and Jackson (T. Heimburg and A. D. Jackson, Proc. Natl. Acad. Sci. 2005, 102, 9790-9795).
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Affiliation(s)
- Ulf R Pedersen
- DNRF Centre Glass and Time, IMFUFA, Department of Sciences, Roskilde University, Postbox 260, DK-4000 Roskilde, Denmark.
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16
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Rodgers JM, Webb M, Smit B. Alcohol solubility in a lipid bilayer: Efficient grand-canonical simulation of an interfacially active molecule. J Chem Phys 2010; 132:064107. [PMID: 20151733 DOI: 10.1063/1.3314289] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We derive a new density-biased Monte Carlo technique which preserves detailed balance and improves the convergence of grand-canonical simulations of a species with a strong preference for an interfacial region as compared to the bulk. This density-biasing technique is applied to the solubility of "alcohol" molecules in a mesoscopic model of the lipid bilayer, a system which has anesthetic implications but is poorly understood.
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Affiliation(s)
- Jocelyn M Rodgers
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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17
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Sul S, Feng Y, Le U, Tobias DJ, Ge NH. Interactions of tyrosine in Leu-enkephalin at a membrane-water interface: an ultrafast two-dimensional infrared study combined with density functional calculations and molecular dynamics simulations. J Phys Chem B 2010; 114:1180-90. [PMID: 20017523 DOI: 10.1021/jp9105844] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The interactions of neuropeptides and membranes play an important role in peptide hormone function. Our current understanding of peptide-membrane interactions remains limited due to the paucity of experimental techniques capable of probing such interactions. In this work, we study the nature of opioid peptide-membrane interactions using ultrafast two-dimensional infrared (2D IR) spectroscopy. The high temporal resolution of 2D IR is particularly suited for studying highly flexible opioid peptides. We investigate the location of the tyrosine (Tyr) side chain of leucine-enkephalin (Lenk) in lipid bilayer membranes by measuring spectral diffusion of the phenolic ring vibrational mode in three different systems: Lenk in lipid bilayer membranes (bicelles), Lenk in deuterated water, and p-cresol in deuterated water. Frequency-frequency correlation functions obtained from waiting-time-dependent 2D IR spectra reveal an ultrafast decaying component with an approximately 1 ps time constant that is common for all three systems. On the basis of density functional theory calculations and molecular dynamics simulations, this spectral diffusion component is attributed to hydrogen-bond dynamics of the phenolic hydroxyl group interacting with bulk water. Unlike p-cresol in water, both Lenk systems exhibit static spectral inhomogeneity, which can be attributed to conformational distributions of Lenk that do not interconvert within 4 ps. Our results suggest that the Tyr side chain of Lenk in bicelles is located at the water-abundant region at the membrane-water interface and not embedded into the hydrophobic core.
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Affiliation(s)
- Soohwan Sul
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
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18
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Hartshorn CM, Jewett CM, Brozik JA. Molecular effects of a nanocrystalline quartz support upon planar lipid bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:2609-2617. [PMID: 20085365 DOI: 10.1021/la904308g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Supported lipid bilayer membranes play a vital role in a number of applications from biosensors to fundamental studies of membrane proteins. It is widely understood that the underlying solid support in such assemblies causes large perturbations to the lipid bilayer as compared with black lipid membranes, but the exact nature of these effects on the membrane by the solid support is less understood. Here, all-atom molecular dynamics simulations of DLPC, DMPC, POPC, and DEPC on a hydroxylated nanocrystalline alpha-quartz (011) slab have revealed a pronounced thinning effect. It is shown that this thinning effect proceeds by one of two mechanisms; the first is through a curling of the terminal methyl groups at the interface of opposing leaflets, and the second is through increased interdigitation of the alkyl chains. In all cases, it is shown that the thinning effect is accompanied by a commensurate spreading of the lipid membrane across the quartz substrate. Also, with the introduction of the solid support, a marked asymmetry in a number of structural properties is reported. These asymmetries include (a) the surface areas per lipid, (b) the electron probabilities of the polar headgroups, (c) the radial distributions of the choline groups, and (d) the average orientation of water surrounding the membranes. Finally, asymmetries associated with the different interaction energies within each system studied are reported. These unequal interaction energies lead to a net force holding the membrane to the surface of the support. It was found that direct membrane-substrate interactions play only a minor role in holding the membrane to the surface and it is the interstitial water that dominates these interactions. This is due to the fact that the water throughout the interstitial region displays an average orientational preference that is more favorable (attractive to the membrane and yields a higher number of hydrogen bonds) than water in the external region of the assembly.
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Affiliation(s)
- Christopher M Hartshorn
- Department of Chemistry, Washington State University, P.O. Box 644630, Pullman, Washington 99164-4630, USA
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19
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Nandi S, Ma L, Denis M, Karwatsky J, Li Z, Jiang XC, Zha X. ABCA1-mediated cholesterol efflux generates microparticles in addition to HDL through processes governed by membrane rigidity. J Lipid Res 2009; 50:456-466. [DOI: 10.1194/jlr.m800345-jlr200] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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20
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Peters GH, Hansen FY, Møller MS, Westh P. Effects of Fatty Acid Inclusion in a DMPC Bilayer Membrane. J Phys Chem B 2008; 113:92-102. [DOI: 10.1021/jp806205m] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Günther H. Peters
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; Department of Life Sciences and Chemistry, Roskilde University, 4000 Roskilde, Denmark; and MEMPHYS-Center for Biomembrane Physics
| | - Flemming Y. Hansen
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; Department of Life Sciences and Chemistry, Roskilde University, 4000 Roskilde, Denmark; and MEMPHYS-Center for Biomembrane Physics
| | - Martin S. Møller
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; Department of Life Sciences and Chemistry, Roskilde University, 4000 Roskilde, Denmark; and MEMPHYS-Center for Biomembrane Physics
| | - Peter Westh
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark; Department of Life Sciences and Chemistry, Roskilde University, 4000 Roskilde, Denmark; and MEMPHYS-Center for Biomembrane Physics
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Högberg CJ, Nikitin AM, Lyubartsev AP. Modification of the CHARMM force field for DMPC lipid bilayer. J Comput Chem 2008; 29:2359-69. [PMID: 18512235 DOI: 10.1002/jcc.20974] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The CHARMM force field for DMPC lipids was modified in order to improve agreement with experiment for a number of important properties of hydrated lipid bilayer. The modification consists in introduction of a scaling factor 0.83 for 1-4 electrostatic interactions (between atoms separated by three covalent bonds), which provides correct transgauche ratio in the alkane tails, and recalculation of the headgroup charges on the basis of HF/6-311(d,p) ab-initio computations. Both rigid TIP3P and flexible SPC water models were used with the new lipid model, showing similar results. The new model in a 75 ns simulation has shown a correct value of the area per lipid at zero surface tension, as well as good agreement with the experiment for the electron density, structure factor, and order parameters, including those in the headgroup part of lipids.
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Affiliation(s)
- Carl-Johan Högberg
- Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, SE-10691, Sweden
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Bailey NP, Pedersen UR, Gnan N, Schrøder TB, Dyre JC. Pressure-energy correlations in liquids. II. Analysis and consequences. J Chem Phys 2008; 129:184508. [DOI: 10.1063/1.2982249] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Molecular dynamics simulations of microstructure and mixing dynamics of cryoprotective solvents in water and in the presence of a lipid membrane. Biophys Chem 2008; 136:23-31. [DOI: 10.1016/j.bpc.2008.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Revised: 04/07/2008] [Accepted: 04/08/2008] [Indexed: 11/20/2022]
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Matubayasi N, Shinoda W, Nakahara M. Free-energy analysis of the molecular binding into lipid membrane with the method of energy representation. J Chem Phys 2008; 128:195107. [DOI: 10.1063/1.2919117] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Patel RY, Balaji PV. Characterization of Symmetric and Asymmetric Lipid Bilayers Composed of Varying Concentrations of Ganglioside GM1 and DPPC. J Phys Chem B 2008; 112:3346-56. [DOI: 10.1021/jp075975l] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Högberg CJ, Lyubartsev AP. Effect of local anesthetic lidocaine on electrostatic properties of a lipid bilayer. Biophys J 2007; 94:525-31. [PMID: 17720733 PMCID: PMC2157248 DOI: 10.1529/biophysj.107.104208] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The influence of the local anesthetic lidocaine on electrostatic properties of a lipid membrane bilayer was studied by molecular dynamics simulations. The electrostatic dipole potential, charge densities, and orientations of the headgroup angle have been examined in the presence of different amounts of charged or uncharged forms of lidocaine. Important changes in the membrane properties caused by the presence of both forms of lidocaine are presented and discussed. Our simulations have shown that both charged and uncharged lidocaine cause almost the same increase in the electrostatic potential in the middle of the membrane, although for different reasons. The increase, approximately 90 mV for 9 mol % of lidocaine and 220 mV for 28 mol % of lidocaine, is of a size that may affect the functioning of voltage-gated ion channels.
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Affiliation(s)
- Carl-Johan Högberg
- Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden
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