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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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2
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Duran T, P Costa A, Kneski J, Xu X, J Burgess D, Mohammadiarani H, Chaudhuri B. Manufacturing process of liposomal Formation: A coarse-grained molecular dynamics simulation. Int J Pharm 2024; 659:124288. [PMID: 38815641 DOI: 10.1016/j.ijpharm.2024.124288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/01/2024]
Abstract
A method of producing liposomes has been previously developed using a continuous manufacturing technology that involves a co-axial turbulent jet in co-flow. In this study, coarse-grained molecular dynamics (CG-MD) simulations were used to gain a deeper understanding of how the self-assembly process of liposomes is affected by the material attributes (such as the concentration of ethanol) and the process parameters (such as temperature), while also providing detailed information on a nano-scale molecular level. Specifically, the CG-MD simulations yield a comprehensive internal view of the structure and formation mechanisms of liposomes containing DPPC, DPPG, and cholesterol molecules. The importance of this work is that structural details on the molecular level are proposed, and such detail is not possible to obtain through experimental studies alone. The assessment of structural properties, including the area per lipid, diffusion coefficient, and order parameters, indicated that a thicker bilayer was observed at higher ethanol concentrations, while a thinner bilayer was present at higher temperatures. These conditions led to more water penetrating the interior of the bilayer and an unstable structure, as indicated by a larger contact area between lipids and water, and a higher coefficient of lipid lateral diffusion. However, stable liposomes were found through these evaluations at lower ethanol concentrations and/or lower process temperatures. Furthermore, the CG-MD model was further compared and validated with experimental and computational data including liposomal bilayer thickness and area per lipid measurements.
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Affiliation(s)
- Tibo Duran
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs CT 06269, USA
| | - Antonio P Costa
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs CT 06269, USA
| | - Jake Kneski
- Department of Chemical & Biomolecular Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Xiaoming Xu
- Office of Testing and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Diane J Burgess
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs CT 06269, USA
| | | | - Bodhisattwa Chaudhuri
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs CT 06269, USA; Department of Chemical & Biomolecular Engineering, University of Connecticut, Storrs, CT 06269, USA; Institute of Material Sciences (IMS), University of Connecticut, Storrs CT, 06269, USA.
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Rózsa ZB, Hantal G, Szőri M, Fábián B, Jedlovszky P. Understanding the Molecular Mechanism of Anesthesia: Effect of General Anesthetics and Structurally Similar Non-Anesthetics on the Properties of Lipid Membranes. J Phys Chem B 2023. [PMID: 37368412 DOI: 10.1021/acs.jpcb.3c02976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
General anesthesia can be caused by various, chemically very different molecules, while several other molecules, many of which are structurally rather similar to them, do not exhibit anesthetic effects at all. To understand the origin of this difference and shed some light on the molecular mechanism of general anesthesia, we report here molecular dynamics simulations of the neat dipalmitoylphosphatidylcholine (DPPC) membrane as well as DPPC membranes containing the anesthetics diethyl ether and chloroform and the structurally similar non-anesthetics n-pentane and carbon tetrachloride, respectively. To also account for the pressure reversal of anesthesia, these simulations are performed both at 1 bar and at 600 bar. Our results indicate that all solutes considered prefer to stay both in the middle of the membrane and close to the boundary of the hydrocarbon domain, at the vicinity of the crowded region of the polar headgroups. However, this latter preference is considerably stronger for the (weakly polar) anesthetics than for the (apolar) non-anesthetics. Anesthetics staying in this outer preferred position increase the lateral separation between the lipid molecules, giving rise to a decrease of the lateral density. The lower lateral density leads to an increased mobility of the DPPC molecules, a decreased order of their tails, an increase of the free volume around this outer preferred position, and a decrease of the lateral pressure at the hydrocarbon side of the apolar/polar interface, a change that might well be in a causal relation with the occurrence of the anesthetic effect. All these changes are clearly reverted by the increase of pressure. Furthermore, non-anesthetics occur in this outer preferred position in a considerably smaller concentration and hence either induce such changes in a much weaker form or do not induce them at all.
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Affiliation(s)
- Zsófia B Rózsa
- Institute of Chemistry, University of Miskolc, Egyetemváros A/2, H-3515 Miskolc, Hungary
| | - György Hantal
- Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Peter Jordan Straße 82, A-1190 Vienna, Austria
| | - Milán Szőri
- Institute of Chemistry, University of Miskolc, Egyetemváros A/2, H-3515 Miskolc, Hungary
| | - Balázs Fábián
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 2, CZ-16610 Prague 6, Czech Republic
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly Catholic University, Leányka utca 6, H-3300 Eger, Hungary
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Dymond MK. A Membrane Biophysics Perspective on the Mechanism of Alcohol Toxicity. Chem Res Toxicol 2023. [PMID: 37186813 DOI: 10.1021/acs.chemrestox.3c00039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Motivations for understanding the underlying mechanisms of alcohol toxicity range from economical to toxicological and clinical. On the one hand, acute alcohol toxicity limits biofuel yields, and on the other hand, acute alcohol toxicity provides a vital defense mechanism to prevent the spread of disease. Herein the role that stored curvature elastic energy (SCE) in biological membranes might play in alcohol toxicity is discussed, for both short and long-chain alcohols. Structure-toxicity relationships for alcohols ranging from methanol to hexadecanol are collated, and estimates of alcohol toxicity per alcohol molecule in the cell membrane are made. The latter reveal a minimum toxicity value per molecule around butanol before alcohol toxicity per molecule increases to a maximum around decanol and subsequently decreases again. The impact of alcohol molecules on the lamellar to inverse hexagonal phase transition temperature (TH) is then presented and used as a metric to assess the impact of alcohol molecules on SCE. This approach suggests the nonmonotonic relationship between alcohol toxicity and chain length is consistent with SCE being a target of alcohol toxicity. Finally, in vivo evidence for SCE-driven adaptations to alcohol toxicity in the literature are discussed.
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Affiliation(s)
- Marcus K Dymond
- Chemistry Research and Enterprise Group, University of Brighton, Huxley Building, Lewes Road, Brighton BN2 4GJ, United Kingdom
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Blood Vessels as a Key Mediator for Ethanol Toxicity: Implication for Neuronal Damage. LIFE (BASEL, SWITZERLAND) 2022; 12:life12111882. [PMID: 36431016 PMCID: PMC9696276 DOI: 10.3390/life12111882] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022]
Abstract
Excessive intake of ethanol is associated with severe brain dysfunction, and the subsequent neurological and behavioral abnormalities are well-established social risks. Many research studies have addressed how ethanol induces neurological toxicity. However, the underlying mechanisms with which ethanol induces neurological toxicity are still obscure, perhaps due to the variety and complexity of these mechanisms. Epithelial cells are in direct contact with blood and can thus mediate ethanol neurotoxicity. Ethanol activates the endothelial cells of blood vessels, as well as lymphatic vessels, in a concentration-dependent manner. Among various signaling mediators, nitric oxide plays important roles in response to ethanol. Endothelial and inducible nitric oxide synthases (eNOS and iNOS) are upregulated and activated by ethanol and enhance neuroinflammation. On the other hand, angiogenesis and blood vessel remodeling are both affected by ethanol intake, altering blood supply and releasing angiocrine factors to regulate neuronal functions. Thus, ethanol directly acts on endothelial cells, yet the molecular target(s) on endothelial cells remain unknown. Previous studies on neurons and glial cells have validated the potential contribution of membrane lipids and some specific proteins as ethanol targets, which may also be the case in endothelial cells. Future studies, based on current knowledge, will allow for a greater understanding of the contribution and underlying mechanisms of endothelial cells in ethanol-induced neurological toxicity, protecting neurological health against ethanol toxicity.
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Anticarcinogenic Trimethoxybenzoate of Catechin Stabilizes the Liquid Crystalline Bilayer Phase in Phosphatidylethanolamine Membranes. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Wang H, Qin H, Garab G, Gasanoff ES. Short-Chained Alcohols Make Membrane Surfaces Conducive for Melittin Action: Implication for the Physiological Role of Alcohols in Cells. Cells 2022; 11:cells11121928. [PMID: 35741057 PMCID: PMC9221640 DOI: 10.3390/cells11121928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/11/2022] [Accepted: 06/14/2022] [Indexed: 11/16/2022] Open
Abstract
Alcohols are a part of cellular metabolism, but their physiological roles are not well understood. We investigated the effects of short-chain alcohols on Daphnia pulex and model membranes mimicking the lipid composition of eukaryotic inner mitochondrial membranes. We also studied the synergistic effects of alcohols with the bee venom membrane-active peptide, melittin, which is structurally similar to endogenous membrane-active peptides. The alcohols, from ethanol to octanol, gradually decreased the heart rate and the mitochondrial ATP synthesis of daphnia; in contrast, in combination with melittin, which exerted no sizeable effect, they gradually increased both the heart rate and the ATP synthesis. Lipid packing and the order parameter of oriented films, monitored by EPR spectroscopy of the spin-labeled probe 5-doxylstrearic acid, revealed gradual alcohol-assisted bilayer to non-bilayer transitions in the presence of melittin; further, while the alcohols decreased, in combination with melittin they increased the order parameter of the film, which is attributed to the alcohol-facilitated association of melittin with the membrane. A 1H-NMR spectroscopy of the liposomes confirmed the enhanced induction of a non-bilayer lipid phase that formed around the melittin, without the permeabilization of the liposomal membrane. Our data suggest that short-chain alcohols, in combination with endogenous peptides, regulate protein functions via modulating the lipid polymorphism of membranes.
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Affiliation(s)
- Haoyu Wang
- STEM (Science, Technology, Engineering and Mathematics) Program, Science Department, Chaoyang KaiWen Academy, Beijing 100018, China; (H.W.); (H.Q.)
| | - Hao Qin
- STEM (Science, Technology, Engineering and Mathematics) Program, Science Department, Chaoyang KaiWen Academy, Beijing 100018, China; (H.W.); (H.Q.)
| | - Győző Garab
- Biological Research Centre, Eötvös Loránd Research Network, Temesvári krt. 62, H-6726 Szeged, Hungary
- Department of Physics, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
- Correspondence: (G.G.); (E.S.G.)
| | - Edward S. Gasanoff
- STEM (Science, Technology, Engineering and Mathematics) Program, Science Department, Chaoyang KaiWen Academy, Beijing 100018, China; (H.W.); (H.Q.)
- Belozersky Institute for Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
- Correspondence: (G.G.); (E.S.G.)
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Zhou T, Wu Z, Das S, Eslami H, Müller-Plathe F. How Ethanolic Disinfectants Disintegrate Coronavirus Model Membranes: A Dissipative Particle Dynamics Simulation Study. J Chem Theory Comput 2022; 18:2597-2615. [PMID: 35286098 PMCID: PMC8938819 DOI: 10.1021/acs.jctc.1c01120] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Indexed: 01/03/2023]
Abstract
We have developed dissipative particle dynamics models for pure dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), and dimyristoylphosphatidylcholine (DMPC) as well as their binary and ternary mixed membranes, as coronavirus model membranes. The stabilities of pure and mixed membranes, surrounded by aqueous solutions containing up to 70 mol % ethanol (alcoholic disinfectants), have been investigated at room temperature. We found that aqueous solutions containing 5-10 mol % ethanol already have a significant weakening effect on the pure and mixed membranes. The magnitude of the effect depends on the membrane composition and the ethanol concentration. Ethanol permeabilizes the membrane, causing its lateral swelling and thickness shrinking and reducing the orientational order of the hydrocarbon tail of the bilayer. The free energy barrier for the permeation of ethanol in the bilayers is considerably reduced by the ethanol uptake. The rupture-critical ethanol concentrations causing the membrane failure are 20.7, 27.5, and 31.7 mol % in the aqueous phase surrounding pure DMPC, DOPC, and DPPC membranes, respectively. Characterizing the failure of lipid membranes by a machine-learning neural network framework, we found that all mixed binary and/or ternary membranes disrupt when immersed in an aqueous solution containing a rupture-critical ethanol concentration, ranging from 20.7 to 31.7 mol %, depending on the composition of the membrane; the DPPC-rich membranes are more intact, while the DMPC-rich membranes are least intact. Due to the tight packing of long, saturated hydrocarbon tails in DPPC, increasing the DPPC content of the mixed membrane increases its stability against the disinfectant. At high DPPC concentrations, where the DOPC and DMPC molecules are confined between the DPPC lipids, the ordered hydrocarbon tails of DPPC also induce order in the DOPC and DMPC molecules and, hence, stabilize the membrane more. Our simulations on pure and mixed membranes of a diversity of compositions reveal that a maximum ethanol concentration of 32 mol % (55 wt %) in the alcohol-based disinfectants is enough to disintegrate any membrane composed of these three lipids.
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Affiliation(s)
- Tianhang Zhou
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
| | - Zhenghao Wu
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
| | - Shubhadip Das
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
| | - Hossein Eslami
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
- College of Sciences, Persian Gulf
University, Boushehr 75168, Iran
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
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9
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Reyes-Figueroa AD, Karttunen M, Ruiz-Suárez JC. Cholesterol sequestration by xenon nano bubbles leads to lipid raft destabilization. SOFT MATTER 2020; 16:9655-9661. [PMID: 33078812 DOI: 10.1039/d0sm01256d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Combined coarse-grained (CG) and atomistic molecular dynamics (MD) simulations were performed to study the interactions of xenon with model lipid rafts consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) and cholesterol (Chol). At a concentration of 2 Xe/lipid we observed an unexpected result: spontaneous nucleation of Xe nano bubbles which rapidly plunged into the bilayer. In this process Chol, essential for raft stabilization, was pulled out from the raft into the hydrophobic zone. When concentration was further increased (3 Xe/lipid), the bubbles increase in size and disrupted both the membrane and raft. We computed the radial distribution functions, pair-wise potentials, second virial coefficients and Schlitter entropy to scrutinize the nature of the interactions. Our findings, concurring with a recent report on the origin of general anaesthesia (M. A. Pavel, E. N. Petersen, H. Wang, R. A. Lerner and S. B. Hansen, Proc. Natl. Acad. Sci. U. S. A., 2020, 117(24), 13757-13766), suggest that the well-known anaesthetic effect of Xe could be mediated by sequestration of Chol, which, in turn, compromises the stability of rafts where specialized proteins needed to produce the nervous signal are anchored.
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10
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Zapata-Morin PA, Sierra-Valdez FJ, Ruiz-Suárez JC. The cut-off effect of n-alcohols in lipid rafts: A lipid-dependent phenomenon ☆. J Mol Graph Model 2020; 101:107732. [PMID: 32920240 DOI: 10.1016/j.jmgm.2020.107732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 10/23/2022]
Abstract
n-Aliphatic alcohols act as anesthetics only up to a certain chain length, beyond which its biological activity disappears. This is known as the 'cut-off' phenomenon. Although the most accepted explanation is based on action sites in membrane proteins, it is not well understood why alcohols alter their functions. The structural dependence of these protein receptors to lipid domains known as 'lipid rafts', suggests a new approach to tackle the puzzling phenomenon. In this work, by performing molecular dynamic simulations (MDS) to explore the lipid role, we provide relevant molecular details about the membrane-alcohol interaction at the cut-off point regime. Since the high variability of the cut-off points found on protein receptors in neurons may be a consequence of differences in the lipid composition surrounding such proteins, our results could have a clear-cut importance.
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Affiliation(s)
- Patricio A Zapata-Morin
- Facultad de Ciencias Biológicas, Laboratorio de Micología y Fitopatología, Universidad Autónoma de Nuevo León, San Nicolás de Los Garza, Nuevo León, 66455, Mexico
| | - F J Sierra-Valdez
- Centro de Investigación Biomédica, Hospital Zambrano Hellion, TecSalud, Ave. Batallón de San Patricio 112, San Pedro Garza García, 66278, Nuevo León, Mexico; Tecnológico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501 Sur, Monterrey, Nuevo León, 64849, Mexico
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Kubiak-Tomaszewska G, Tomaszewski P, Pachecka J, Struga M, Olejarz W, Mielczarek-Puta M, Nowicka G. Molecular mechanisms of ethanol biotransformation: enzymes of oxidative and nonoxidative metabolic pathways in human. Xenobiotica 2020; 50:1180-1201. [PMID: 32338108 DOI: 10.1080/00498254.2020.1761571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ethanol, as a small-molecule organic compound exhibiting both hydrophilic and lipophilic properties, quickly pass through the biological barriers. Over 95% of absorbed ethanol undergoes biotransformation, the remaining amount is excreted unchanged, mainly with urine and exhaled air.The main route of ethyl alcohol metabolism is its oxidation to acetaldehyde, which is converted into acetic acid with the participation of cytosolic NAD+ - dependent alcohol (ADH) and aldehyde (ALDH) dehydrogenases. Oxidative biotransformation pathways of ethanol also include reactions catalyzed by the microsomal ethanol oxidizing system (MEOS), peroxisomal catalase and aldehyde (AOX) and xanthine (XOR) oxidases. The resulting acetic acid can be activated to acetyl-CoA by the acetyl-CoA synthetase (ACS).It is also possible, to a much smaller extent, non-oxidative routes of ethanol biotransformation including its esterification with fatty acids by ethyl fatty acid synthase (FAEES), re-esterification of phospholipids, especially phosphatidylcholines, with phospholipase D (PLD), coupling with sulfuric acid by alcohol sulfotransferase (SULT) and with glucuronic acid using UDP-glucuronyl transferase (UGT, syn. UDPGT).The intestinal microbiome plays a significant role in the ethanol biotransformation and in the initiation and progression of liver diseases stimulated by ethanol and its metabolite - acetaldehyde, or by lipopolysaccharide and ROS.
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Affiliation(s)
- Grażyna Kubiak-Tomaszewska
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
| | - Piotr Tomaszewski
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
| | - Jan Pachecka
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
| | - Marta Struga
- Department of Biochemistry, Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Wioletta Olejarz
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
| | | | - Grażyna Nowicka
- Department of Biochemistry and Clinical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
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Ethanol Decreases Pseudomonas aeruginosa Flagellar Motility through the Regulation of Flagellar Stators. J Bacteriol 2019; 201:JB.00285-19. [PMID: 31109994 DOI: 10.1128/jb.00285-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 05/17/2019] [Indexed: 12/16/2022] Open
Abstract
Pseudomonas aeruginosa frequently encounters microbes that produce ethanol. Low concentrations of ethanol reduced P. aeruginosa swim zone area by up to 45% in soft agar. The reduction of swimming by ethanol required the flagellar motor proteins MotAB and two PilZ domain proteins (FlgZ and PilZ). PilY1 and the type 4 pilus alignment complex (comprising PilMNOP) were previously implicated in MotAB regulation in surface-associated cells and were required for ethanol-dependent motility repression. As FlgZ requires the second messenger bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) to represses motility, we screened mutants lacking genes involved in c-di-GMP metabolism and found that mutants lacking diguanylate cyclases SadC and GcbA were less responsive to ethanol. The double mutant was resistant to its effects. As published previously, ethanol also represses swarming motility, and the same genes required for ethanol effects on swimming motility were required for its regulation of swarming. Microscopic analysis of single cells in soft agar revealed that ethanol effects on swim zone area correlated with ethanol effects on the portion of cells that paused or stopped during the time interval analyzed. Ethanol increased c-di-GMP in planktonic wild-type cells but not in ΔmotAB or ΔsadC ΔgcbA mutants, suggesting c-di-GMP plays a role in the response to ethanol in planktonic cells. We propose that ethanol produced by other microbes induces a regulated decrease in P. aeruginosa motility, thereby promoting P. aeruginosa colocalization with ethanol-producing microbes. Furthermore, some of the same factors involved in the response to surface contact are involved in the response to ethanol.IMPORTANCE Ethanol is an important biologically active molecule produced by many bacteria and fungi. It has also been identified as a potential marker for disease state in cystic fibrosis. In line with previous data showing that ethanol promotes biofilm formation by Pseudomonas aeruginosa, here we report that ethanol reduces swimming motility using some of the same proteins involved in surface sensing. We propose that these data may provide insight into how microbes, via their metabolic byproducts, can influence P. aeruginosa colocalization in the context of infection and in other polymicrobial settings.
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Rao BD, Shrivastava S, Pal S, Chattopadhyay A. Effect of Local Anesthetics on the Organization and Dynamics of Hippocampal Membranes: A Fluorescence Approach. J Phys Chem B 2018; 123:639-647. [DOI: 10.1021/acs.jpcb.8b10232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Bhagyashree D. Rao
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
- CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| | - Sandeep Shrivastava
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Sreetama Pal
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
- CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| | - Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
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14
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Hantal G, Fábián B, Sega M, Jójárt B, Jedlovszky P. Effect of general anesthetics on the properties of lipid membranes of various compositions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:594-609. [PMID: 30571949 DOI: 10.1016/j.bbamem.2018.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/05/2018] [Accepted: 12/13/2018] [Indexed: 10/27/2022]
Abstract
Computer simulations of four lipid membranes of different compositions, namely neat DPPC and PSM, and equimolar DPPC-cholesterol and PSM-cholesterol mixtures, are performed in the presence and absence of the general anesthetics diethylether and sevoflurane both at 1 and 600 bar. The results are analyzed in order to identify membrane properties that are potentially related to the molecular mechanism of anesthesia, namely that change in the same way in any membrane with any anesthetics, and change oppositely with increasing pressure. We find that the lateral lipid density satisfies both criteria: it is decreased by anesthetics and increased by pressure. This anesthetic-induced swelling is attributed to only those anesthetic molecules that are located close to the boundary of the apolar phase. This lateral expansion is found to lead to increased lateral mobility of the lipids, an effect often thought to be related to general anesthesia; to an increased fraction of the free volume around the outer preferred position of anesthetics; and to the decrease of the lateral pressure in the nearby range of the ester and amide groups, a region into which anesthetic molecules already cannot penetrate. All these changes are reverted by the increase of pressure. Another important finding of this study is that cholesterol has an opposite effect on the membrane properties than anesthetics, and, correspondingly, these changes are less marked in the presence of cholesterol. Therefore, changes in the membrane that can lead to general anesthesia are expected to occur in the membrane domains of low cholesterol content.
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Affiliation(s)
- György Hantal
- Faculty of Physics, University of Vienna, Sensengasse 8/9, A-1090 Vienna, Austria
| | - Balázs Fábián
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, H-1111 Budapest, Hungary; Institut UTINAM (CNRS UMR 6213), Université Bourgogne Franche-Comté, 16 route de Gray, F-25030 Besançon, France
| | - Marcello Sega
- Faculty of Physics, University of Vienna, Sensengasse 8/9, A-1090 Vienna, Austria
| | - Balázs Jójárt
- Institute of Food Engineering, University of Szeged, Moszkvai krt 5-7, H-6725 Szeged, Hungary
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly University, Leányka utca 6, H-3300 Eger, Hungary.
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15
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Oakes V, Domene C. Capturing the Molecular Mechanism of Anesthetic Action by Simulation Methods. Chem Rev 2018; 119:5998-6014. [DOI: 10.1021/acs.chemrev.8b00366] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Victoria Oakes
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Carmen Domene
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
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16
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Polley A. Partition of common anesthetic molecules in the liquid disordered phase domain of a composite multicomponent membrane. Phys Rev E 2018; 98:012409. [PMID: 30110859 DOI: 10.1103/physreve.98.012409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Indexed: 01/04/2023]
Abstract
Despite a vast clinical application of anesthetics, the molecular level of understanding of general anesthesia is far from our reach. Using atomistic molecular dynamics simulation, we study the effects of common anesthetics: ethanol, chloroform, and methanol in the fully hydrated symmetric multicomponent lipid bilayer membrane comprised of an unsaturated palmitoyl-oleoyl-phosphatidyl-choline (POPC), a saturated palmitoyl-sphingomyelin, and cholesterol, which exhibits phase coexistence of liquid-ordered (l_{o})-liquid-disordered (l_{d}) phase domains. We find that the mechanical and physical properties such as the thickness and rigidity of the membrane are reduced while the lateral expansion of the membrane is exhibited in the presence of anesthetic molecules. Our simulation shows both lateral and transverse heterogeneity of the anesthetics in the composite multicomponent lipid membrane. Both ethanol and chloroform partition in the POPC-rich l_{d} phase domain, while methanol is distributed in both l_{o}-l_{d} phase domains. Chloroform can penetrate deep into the membrane, while methanol partitions mostly at the water layer closed to the head group and ethanol at the neck of the lipids in the membrane.
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Affiliation(s)
- Anirban Polley
- Department of Chemical Engineering, Columbia University, New York City, New York 10027, USA
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17
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Zhang M, Peyear T, Patmanidis I, Greathouse DV, Marrink SJ, Andersen OS, Ingólfsson HI. Fluorinated Alcohols' Effects on Lipid Bilayer Properties. Biophys J 2018; 115:679-689. [PMID: 30077334 PMCID: PMC6104562 DOI: 10.1016/j.bpj.2018.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/23/2018] [Accepted: 07/02/2018] [Indexed: 12/21/2022] Open
Abstract
Fluorinated alcohols (fluoroalcohols) have physicochemical properties that make them excellent solvents of peptides, proteins, and other compounds. Like other alcohols, fluoroalcohols also alter membrane protein function and lipid bilayer properties and stability. Thus, the questions arise: how potent are fluoroalcohols as lipid-bilayer-perturbing compounds, could small residual amounts that remain after adding compounds dissolved in fluoroalcohols alter lipid bilayer properties sufficiently to affect membranes and membrane protein function, and do they behave like other alcohols? To address these questions, we used a gramicidin-based fluorescence assay to determine the bilayer-modifying potency of selected fluoroalcohols: trifluoroethanol (TFE), HFIP, and perfluoro-tert-butanol (PFTB). These fluoroalcohols alter bilayer properties in the low (PFTB) to high (TFE) mM range. Using the same assay, we determined the bilayer partitioning of the alcohols. When referenced to the aqueous concentrations, the fluoroalcohols are more bilayer perturbing than their nonfluorinated counterparts, with the largest fluoroalcohol, PFTB, being the most potent and the smallest, TFE, the least. When referenced to the mole fractions in the membrane, however, the fluoroalcohols have equal or lesser bilayer-perturbing potency than their nonfluorinated counterparts, with TFE being more bilayer perturbing than PFTB. We compared the fluoroalcohols' molecular level bilayer interactions using atomistic molecular dynamics simulations and showed how, at higher concentrations, they can cause bilayer breakdown using absorbance measurements and 31P nuclear magnetic resonance.
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Affiliation(s)
- Mike Zhang
- Department Physiology and Biophysics, Weill Cornell Medicine, New York City, New York; The Bronx High School of Science, New York City, New York
| | - Thasin Peyear
- Department Physiology and Biophysics, Weill Cornell Medicine, New York City, New York
| | - Ilias Patmanidis
- Groningen Biomolecular Science and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Denise V Greathouse
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas
| | - Siewert J Marrink
- Groningen Biomolecular Science and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Olaf S Andersen
- Department Physiology and Biophysics, Weill Cornell Medicine, New York City, New York.
| | - Helgi I Ingólfsson
- Department Physiology and Biophysics, Weill Cornell Medicine, New York City, New York; Groningen Biomolecular Science and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands; Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California.
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18
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Efimova SS, Chulkov EG, Ostroumova OS. Lipid-mediated mode of action of local anesthetics on lipid pores induced by polyenes, peptides and lipopeptides. Colloids Surf B Biointerfaces 2018. [PMID: 29525621 DOI: 10.1016/j.colsurfb.2018.02.051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effects of local anesthetics (LAs), namely, lidocaine (LDC), prilocaine (PLC), mepivacaine (MPV), bupivacaine (BPV), procaine (PC), and tetracaine (TTC), on the steady-state transmembrane conductance induced by the cis-side addition of the antifungal polyene macrolide antibiotic, nystatin (NYS), in planar lipid bilayers were studied. The addition of TTC to model membranes comprising DOPC and cholesterol (33 mol%) led to a nearly twenty-fold increase in the steady-state NYS-induced membrane conductance. BPV slightly enhanced the channel-forming activity of polyene. LDC, PLC, MPV, and PC did not affect the NYS-induced transmembrane current. We concluded that the effects of LAs on the channel-forming activity of NYS were in agreement with their effects on the elastic properties of model membranes. The ability of aminoamide LAs to promote calcein leakage from large unilamellar DOPC-vesicles was decreased in the following order: BPV >> LDC ≈ PLC ≈ MPV. LDC, PLC, and MPV produced a graded leakage of fluorescent marker from liposomes, up to 10-13%. A initial sharp jump in fluorescence after the introduction of BPV was attributed to the solubilization of liposomes and the formation of mixed DOPC:BPV-micelles. Differential scanning microcalorimetry (DSC) of large unilamellar DPPC-vesicles showed that the main transition temperature (Tm) is continuously decreased upon increasing concentrations of TTC. A sharp drop in the enthalpy of the transition at higher TTC concentrations indicated a formation of anesthetic/lipid mixed micelles. In contrast to TTC, PC slightly decreased Tm, broadened the DSC signal and did not provoke vesicle-to-micelle transition. Both the calcein leakage and DSC data together with the results of measurements of threshold voltages that are required to cause the lipid bilayer breakdown might indicate an alteration in the curvature lipid packing stress, induced by BPV and TTC. The data presented here lend support to a lipid-mediated mode of LAs action on NYS pores via an alteration in curvature stress near the trans-mouth. Similar results were obtained for several lipid pores, formed by polyene amphotericin B, lipopeptide syringomycin E, and the peptides magainin and melittin. This finding further developed the concept of non-specific regulation of lipid pores by LAs. In conclusion, the combination of nystatin with LAs could be a novel treatment for efficient therapy of superficial and mucosal candidiasis.
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Affiliation(s)
- Svetlana S Efimova
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia.
| | - Evgeny G Chulkov
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Olga S Ostroumova
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
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19
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20
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Fábián B, Sega M, Voloshin VP, Medvedev NN, Jedlovszky P. Lateral Pressure Profile and Free Volume Properties in Phospholipid Membranes Containing Anesthetics. J Phys Chem B 2017; 121:2814-2824. [DOI: 10.1021/acs.jpcb.7b00990] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Balázs Fábián
- Department of Inorganic
and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, H-1111 Budapest, Hungary
- Institut UTINAM (CNRS UMR 6213), Université Bourgogne Franche-Comté, 16 route de Gray, F-25030 Besançon, France
| | - Marcello Sega
- Faculty of
Physics, University of Vienna, Sensengasse 8/9, A-1090 Vienna, Austria
| | - Vladimir P. Voloshin
- Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
| | - Nikolai N. Medvedev
- Novosibirsk State University, Novosibirsk 630090, Russia
- Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences (SB RAS), Novosibirsk 630090, Russia
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly University, Leányka utca 6, H-3300 Eger, Hungary
- MTA-BME Research Group of Technical Analytical Chemistry, Szent Gellért tér
4, H-1111 Budapest, Hungary
- Laboratory of Interfaces and Nanosize Systems,
Institute of Chemistry, Eötvös Loránd University, Pázmány Peter Stny 1/A, H-1117 Budapest, Hungary
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21
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Melo M, Arnarez C, Sikkema H, Kumar N, Walko M, Berendsen HJC, Kocer A, Marrink SJ, Ingólfsson HI. High-Throughput Simulations Reveal Membrane-Mediated Effects of Alcohols on MscL Gating. J Am Chem Soc 2017; 139:2664-2671. [PMID: 28122455 PMCID: PMC5343553 DOI: 10.1021/jacs.6b11091] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Indexed: 12/18/2022]
Abstract
The mechanosensitive channels of large conductance (MscL) are bacterial membrane proteins that serve as last resort emergency release valves in case of severe osmotic downshock. Sensing bilayer tension, MscL channels are sensitive to changes in the bilayer environment and are, therefore, an ideal test case for exploring membrane protein coupling. Here, we use high-throughput coarse-grained molecular dynamics simulations to characterize MscL gating kinetics in different bilayer environments under the influence of alcohols. We performed over five hundred simulations to obtain sufficient statistics to reveal the subtle effects of changes in the membrane environment on MscL gating. MscL opening times were found to increase with the addition of the straight-chain alcohols ethanol, octanol, and to some extent dodecanol but not with hexadecanol. Increasing concentration of octanol increased the impeding effect, but only up to 10-20 mol %. Our in silico predictions were experimentally confirmed using reconstituted MscL in a liposomal fluorescent efflux assay. Our combined data reveal that the effect of alcohols on MscL gating arises not through specific binding sites but through a combination of the alcohol-induced changes to a number of bilayer properties and their alteration of the MscL-bilayer interface. Our work provides a key example of how extensive molecular simulations can be used to predict the functional modification of membrane proteins by subtle changes in their bilayer environment.
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Affiliation(s)
- Manuel
N. Melo
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Clément Arnarez
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Hendrik Sikkema
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Neeraj Kumar
- Groningen
Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Martin Walko
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Herman J. C. Berendsen
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Armagan Kocer
- Department
of Neuroscience, University Medical Center
Groningen, University of Groningen, Antonius Deusinglaan 1, 99713 AV, Groningen, The
Netherlands
| | - Siewert J. Marrink
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Helgi I. Ingólfsson
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
- Biosciences
and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
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22
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Ghoraishi MS, Hawk JE, Phani A, Khan MF, Thundat T. Clustering mechanism of ethanol-water mixtures investigated with photothermal microfluidic cantilever deflection spectroscopy. Sci Rep 2016; 6:23966. [PMID: 27046089 PMCID: PMC4820714 DOI: 10.1038/srep23966] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 03/15/2016] [Indexed: 11/09/2022] Open
Abstract
The infrared-active (IR) vibrational mode of ethanol (EtOH) associated with the asymmetrical stretching of the C-C-O bond in pico-liter volumes of EtOH-water binary mixtures is calorimetrically measured using photothermal microfluidic cantilever deflection spectroscopy (PMCDS). IR absorption by the confined liquid results in wavelength dependent cantilever deflections, thus providing a complementary response to IR absorption revealing a complex dipole moment dependence on mixture concentration. Solvent-induced blue shifts of the C-C-O asymmetric vibrational stretch for both anti and gauche conformers of EtOH were precisely monitored for EtOH concentrations ranging from 20-100% w/w. Variations in IR absorption peak maxima show an inverse dependence on induced EtOH dipole moment (μ) and is attributed to the complex clustering mechanism of EtOH-water mixtures.
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Affiliation(s)
- M. S. Ghoraishi
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
| | - J. E. Hawk
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
| | - Arindam Phani
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
| | - M. F. Khan
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
| | - T. Thundat
- Department of Chemical and Material Engineering, University of Alberta, Edmonton, Canada
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23
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Bothun GD, Boltz L, Kurniawan Y, Scholz C. Cooperative effects of fatty acids and n-butanol on lipid membrane phase behavior. Colloids Surf B Biointerfaces 2015; 139:62-7. [PMID: 26700234 DOI: 10.1016/j.colsurfb.2015.11.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 11/24/2015] [Accepted: 11/26/2015] [Indexed: 11/25/2022]
Abstract
Biodiesel-derived crude glycerol can be fermented to produce n-butanol, which is a platform chemical for biorefining and a biofuel. One limitation to crude glycerol fermentation is the presence of long-chain fatty acids (FAs) that can partition into cellular membranes, leading to membrane fluidization and interdigitation, which can inhibit cellular function. In this work, we have examined the phase behavior of dipalmitoylphosphatidylcholine (DPPC, C16:0) membranes and the membrane partitioning of n-butanol as a function of FA degree of unsaturation (steric, oleic, and linoleic acids) using differential scanning calorimetry (DSC) and monolayer surface pressure studies. All three FAs at 15mol% (85mol% DPPC) prevented interdigitation by n-butanol based on the DSC results. n-Butanol partitioning and membrane expansion was greatest for DPPC/oleic acid membranes, where monounsaturated oleic acid (OA, C18:1) was miscible in gel and fluid phase DPPC. Saturated steric acid (SA, C18:0), which ordered the membranes and yielded a SA-rich phase during melting, led to a modest increase in n-butanol partitioning compared to DPPC alone. Di-unsaturated linoleic acid (LA, C18:2), which disordered the membranes and phase separated, had little affect on n-butanol partitioning into the DPPC-rich phases. The effects of OA and LA are attributed to the additional interfacial area provided by these FAs due to acyl tail 'kinks' at the carbon double bonds. These results show that exogenous FAs can partition into membranes, impacting n-butanol partitioning and acting cooperatively with n-butanol to alter membrane structure.
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Affiliation(s)
- Geoffrey D Bothun
- Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Rd, Kingston, RI, United States.
| | - Lauren Boltz
- Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Rd, Kingston, RI, United States
| | - Yogi Kurniawan
- Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Rd, Kingston, RI, United States
| | - Carmen Scholz
- Department of Chemistry, University of Alabama in Huntsville, 301 Sparkman Dr, Huntsville, AL, United States
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24
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Odinokov A, Ostroumov D. Structural Degradation and Swelling of Lipid Bilayer under the Action of Benzene. J Phys Chem B 2015; 119:15006-13. [PMID: 26555804 DOI: 10.1021/acs.jpcb.5b09420] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Benzene and other nonpolar organic solvents can accumulate in the lipid bilayer of cellular membranes. Their effect on the membrane structure and fluidity determines their toxic properties and antibiotic action of the organic solvents on the bacteria. We performed molecular dynamics simulations of the interaction of benzene with the dimyristoylphosphatidylcholine (DMPC) bilayer. An increase in the membrane surface area and fluidity was clearly detected. Changes in the acyl chain ordering, tilt angle, and overall bilayer thickness were, however, much less marked. The dependence of all computed quantities on the benzene content showed two regimes separated by the solubility limit of benzene in water. When the amount of benzene exceeded this point, a layer of almost pure benzene started to grow between the membrane leaflets. This process corresponds to the nucleation of a new phase and provides a molecular mechanism for the mechanical rupture of the bilayer under the action of nonpolar compounds.
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Affiliation(s)
- Alexey Odinokov
- Photochemistry Center of the Russian Academy of Sciences, 7a Novatorov ul., Moscow, 119421, Russia
| | - Denis Ostroumov
- Photochemistry Center of the Russian Academy of Sciences, 7a Novatorov ul., Moscow, 119421, Russia.,Moscow Institute of Physics and Technology , 9 Institutskiy per., Dolgoprudny, Moscow Region, 141700, Russia
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25
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Baul U, Kuroda K, Vemparala S. Interaction of multiple biomimetic antimicrobial polymers with model bacterial membranes. J Chem Phys 2015; 141:084902. [PMID: 25173040 DOI: 10.1063/1.4893440] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using atomistic molecular dynamics simulations, interaction of multiple synthetic random copolymers based on methacrylates on prototypical bacterial membranes is investigated. The simulations show that the cationic polymers form a micellar aggregate in water phase and the aggregate, when interacting with the bacterial membrane, induces clustering of oppositely charged anionic lipid molecules to form clusters and enhances ordering of lipid chains. The model bacterial membrane, consequently, develops lateral inhomogeneity in membrane thickness profile compared to polymer-free system. The individual polymers in the aggregate are released into the bacterial membrane in a phased manner and the simulations suggest that the most probable location of the partitioned polymers is near the 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG) clusters. The partitioned polymers preferentially adopt facially amphiphilic conformations at lipid-water interface, despite lacking intrinsic secondary structures such as α-helix or β-sheet found in naturally occurring antimicrobial peptides.
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Affiliation(s)
- Upayan Baul
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
| | - Kenichi Kuroda
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109, USA
| | - Satyavani Vemparala
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
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26
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Han S. Effect of Cholesterol on Ethanol-induced Disruption of a POPC Bilayer: A Molecular Dynamics Simulation Study. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Sanghwa Han
- Department of Biochemistry; Kangwon National University; Chunchon 200-701 Korea
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27
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Konas RM, Daristotle JL, Harbor NB, Klauda JB. Biophysical Changes of Lipid Membranes in the Presence of Ethanol at Varying Concentrations. J Phys Chem B 2015; 119:13134-41. [DOI: 10.1021/acs.jpcb.5b06066] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ryan M. Konas
- Department
of Chemical and Biomolecular Engineering and ‡Biophysics Program and the University
of Maryland Energy Research Center (UMERC), University of Maryland, College
Park, Maryland 20742, United States
| | - John L. Daristotle
- Department
of Chemical and Biomolecular Engineering and ‡Biophysics Program and the University
of Maryland Energy Research Center (UMERC), University of Maryland, College
Park, Maryland 20742, United States
| | - Ndubuisi B. Harbor
- Department
of Chemical and Biomolecular Engineering and ‡Biophysics Program and the University
of Maryland Energy Research Center (UMERC), University of Maryland, College
Park, Maryland 20742, United States
| | - Jeffery B. Klauda
- Department
of Chemical and Biomolecular Engineering and ‡Biophysics Program and the University
of Maryland Energy Research Center (UMERC), University of Maryland, College
Park, Maryland 20742, United States
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28
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Wiącek AE, Adryańczyk E. Interfacial Properties of Phosphatidylcholine-based Dispersed Systems. Ind Eng Chem Res 2015. [DOI: 10.1021/acs.iecr.5b01429] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Agnieszka Ewa Wiącek
- Department of Interfacial
Phenomena, Faculty of Chemistry, Maria Curie-Skłodowska University, 20031 Lublin, Poland
| | - Emilian Adryańczyk
- Department of Interfacial
Phenomena, Faculty of Chemistry, Maria Curie-Skłodowska University, 20031 Lublin, Poland
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29
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Moskovitz Y, Yang H. Modelling of noble anaesthetic gases and high hydrostatic pressure effects in lipid bilayers. SOFT MATTER 2015; 11:2125-2138. [PMID: 25612767 DOI: 10.1039/c4sm02667e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Our objective was to study molecular processes that might be responsible for inert gas narcosis and high-pressure nervous syndrome. The classical molecular dynamics trajectories (200 ns) of dioleoylphosphatidylcholine (DOPC) bilayers simulated by the Berger force field were evaluated for water and the atomic distribution of noble gases around DOPC molecules in the pressure range of 1-1000 bar and at a temperature of 310 K. Xenon and argon have been tested as model gases for general anaesthetics, and neon has been investigated for distortions that are potentially responsible for neurological tremors in hyperbaric conditions. The analysis of stacked radial pair distribution functions of DOPC headgroup atoms revealed the explicit solvation potential of the gas molecules, which correlates with their dimensions. The orientational dynamics of water molecules at the biomolecular interface should be considered as an influential factor, while excessive solvation effects appearing in the lumen of membrane-embedded ion channels could be a possible cause of inert gas narcosis. All the noble gases tested exhibit similar order parameter patterns for both DOPC acyl chains, which are opposite of the patterns found for the order parameter curve at high hydrostatic pressures in intact bilayers. This finding supports the 'critical volume' hypothesis of anaesthesia pressure reversal. The irregular lipid headgroup-water boundary observed in DOPC bilayers saturated with neon in the pressure range of 1-100 bar could be associated with the possible manifestation of neurological tremors at the atomic scale. The non-immobiliser neon also demonstrated the highest momentum impact on the normal component of the DOPC diffusion coefficient representing the monolayer undulation rate, which indicates that enhanced diffusivity rather than atomic size is the key factor.
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Affiliation(s)
- Yevgeny Moskovitz
- Department of Chemistry, Middle Tennessee State University, Murfreesboro, TN 37130, USA
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Pluhackova K, Wassenaar TA, Kirsch S, Böckmann RA. Spontaneous adsorption of coiled-coil model peptides K and E to a mixed lipid bilayer. J Phys Chem B 2015; 119:4396-408. [PMID: 25719673 DOI: 10.1021/acs.jpcb.5b00434] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A molecular description of the lipid-protein interactions underlying the adsorption of proteins to membranes is crucial for understanding, for example, the specificity of adsorption or the binding strength of a protein to a bilayer, or for characterizing protein-induced changes of membrane properties. In this paper, we extend an automated in silico assay (DAFT) for binding studies and apply it to characterize the adsorption of the model fusion peptides E and K to a mixed phospholipid/cholesterol membrane using coarse-grained molecular dynamics simulations. In addition, we couple the coarse-grained protocol to reverse transformation to atomistic resolution, thereby allowing to study molecular interactions with high detail. The experimentally observed differential binding of the peptides E and K to membranes, as well as the increased binding affinity of helical over unstructered peptides, could be well reproduced using the polarizable Martini coarse-grained (CG) force field. Binding to neutral membranes is shown to be dominated by initial binding of the positively charged N-terminus to the phospholipid headgroup region, followed by membrane surface-aligned insertion of the peptide at the interface between the hydrophobic core of the membrane and its polar headgroup region. Both coarse-grained and atomistic simulations confirm a before hypothesized snorkeling of lysine side chains for the membrane-bound state of the peptide K. Cholesterol was found to be enriched in peptide vicinity, which is probably of importance for the mechanism of membrane fusion. The applied sequential multiscale method, using coarse-grained simulations for the slow adsorption process of peptides to membranes followed by backward transformation to atomistic detail and subsequent atomistic simulations of the preformed peptide-lipid complexes, is shown to be a versatile approach to study the interactions of peptides or proteins with biomembranes.
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Affiliation(s)
- Kristyna Pluhackova
- Computational Biology, Department of Biology, University of Erlangen-Nürnberg, Staudtstr. 5, 91052 Erlangen, Germany
| | - Tsjerk A Wassenaar
- Computational Biology, Department of Biology, University of Erlangen-Nürnberg, Staudtstr. 5, 91052 Erlangen, Germany
| | - Sonja Kirsch
- Computational Biology, Department of Biology, University of Erlangen-Nürnberg, Staudtstr. 5, 91052 Erlangen, Germany
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, University of Erlangen-Nürnberg, Staudtstr. 5, 91052 Erlangen, Germany
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Thind R, O'Neill DW, Del Regno A, Notman R. Ethanol induces the formation of water-permeable defects in model bilayers of skin lipids. Chem Commun (Camb) 2015; 51:5406-9. [DOI: 10.1039/c4cc08527b] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We observe that ethanol can induce the formation of water-permeable defects in model bilayers of skin lipids and propose this as a new mechanism of action of ethanol as a membrane modulator.
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Affiliation(s)
- R. Thind
- Department of Chemistry and Centre for Scientific Computing
- University of Warwick
- Coventry
- UK
| | - D. W. O'Neill
- Department of Chemistry and Centre for Scientific Computing
- University of Warwick
- Coventry
- UK
| | - A. Del Regno
- Department of Chemistry and Centre for Scientific Computing
- University of Warwick
- Coventry
- UK
| | - R. Notman
- Department of Chemistry and Centre for Scientific Computing
- University of Warwick
- Coventry
- UK
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Jakobtorweihen S, Zuniga AC, Ingram T, Gerlach T, Keil FJ, Smirnova I. Predicting solute partitioning in lipid bilayers: Free energies and partition coefficients from molecular dynamics simulations and COSMOmic. J Chem Phys 2014; 141:045102. [DOI: 10.1063/1.4890877] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Yoshida K, Horii K, Fujii Y, Nishio I. Real-time observation of liposome bursting induced by acetonitrile. Chemphyschem 2014; 15:2909-12. [PMID: 25065500 DOI: 10.1002/cphc.201402333] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 06/22/2014] [Indexed: 01/26/2023]
Abstract
We show the bursting process of dioleoylphosphatidylcholine (DOPC) liposomes in response to the addition of acetonitrile, a small toxic molecule widely used in the fields of chemistry and industry. The percentage of destroyed liposomes is reduced upon decreasing the acetonitrile fraction in the aqueous solution and vesicle bursting is not observed at volume ratios of 4:6 and below. This indicates that a high fraction of acetonitrile causes the bursting of liposomes, and it is proposed that this occurs through insertion of the molecules into outer leaflet of the lipid bilayer. The elapsed time between initial addition of acetonitrile and liposome bursting at each vesicle is also measured and demonstrated to be dependent on the volume fraction of acetonitrile and the vesicle size.
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Affiliation(s)
- Kazunari Yoshida
- Department of Physics and Mathematics, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258 (Japan).
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Pourmousa M, Róg T, Mikkeli R, Vattulainen L, Solanko LM, Wüstner D, List NH, Kongsted J, Karttunen M. Dehydroergosterol as an Analogue for Cholesterol: Why It Mimics Cholesterol So Well—or Does It? J Phys Chem B 2014; 118:7345-57. [DOI: 10.1021/jp406883k] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Mohsen Pourmousa
- Department
of Physics, Tampere University of Technology, Korkeakoulunkatu 3, 33720 Tampere, Finland
| | - Tomasz Róg
- Department
of Physics, Tampere University of Technology, Korkeakoulunkatu 3, 33720 Tampere, Finland
| | - Risto Mikkeli
- Department
of Applied Physics, Aalto University, P.O. Box 11100, FI-00076 Aalto, Finland
| | - llpo Vattulainen
- Department
of Physics, Tampere University of Technology, Korkeakoulunkatu 3, 33720 Tampere, Finland
- MEMPHYS−Center
of Biomembrane Physics, Physics Department, University of Southern Denmark, Odense, Denmark
| | | | | | | | | | - Mikko Karttunen
- Department
of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo N2L 3G1, Ontario, Canada
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Kopec W, Khandelia H. Reinforcing the membrane-mediated mechanism of action of the anti-tuberculosis candidate drug thioridazine with molecular simulations. J Comput Aided Mol Des 2014; 28:123-34. [DOI: 10.1007/s10822-014-9737-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 02/19/2014] [Indexed: 10/25/2022]
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Nanoscale effects of ethanol and naltrexone on protein organization in the plasma membrane studied by photoactivated localization microscopy (PALM). PLoS One 2014; 9:e87225. [PMID: 24503624 PMCID: PMC3913589 DOI: 10.1371/journal.pone.0087225] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 12/20/2013] [Indexed: 12/04/2022] Open
Abstract
Background Ethanol affects the signaling of several important neurotransmitter and neuromodulator systems in the CNS. It has been recently proposed that ethanol alters the dynamic lateral organization of proteins and lipids in the plasma membrane, thereby affecting surface receptor-mediated cellular signaling. Our aims are to establish whether pharmacologically relevant levels of ethanol can affect the lateral organization of plasma membrane and cytoskeletal proteins at the nanoscopic level, and investigate the relevance of such perturbations for mu-opioid receptor (MOP) function. Methodology/Principal Findings We used Photoactivated Localization Microscopy with pair-correlation analysis (pcPALM), a quantitative fluorescence imaging technique with high spatial resolution (15–25 nm) and single-molecule sensitivity, to study ethanol effects on protein organization in the plasma membrane. We observed that short (20 min) exposure to 20 and 40 mM ethanol alters protein organization in the plasma membrane of cells that harbor endogenous MOPs, causing a rearrangement of the lipid raft marker glycosylphosphatidylinositol (GPI). These effects could be largely occluded by pretreating the cells with the MOP antagonist naltrexone (200 nM for 3 hours). In addition, ethanol induced pronounced actin polymerization, leading to its partial co-localization with GPI. Conclusions/Significance Pharmacologically relevant levels of ethanol alter the lateral organization of GPI-linked proteins and induce actin cytoskeleton reorganization. Pretreatment with the MOP antagonist naltrexone is protective against ethanol action and significantly reduces the extent to which ethanol remodels the lateral organization of lipid-rafts-associated proteins in the plasma membrane. Super-resolution pcPALM reveals details of ethanol action at the nanoscale level, giving new mechanistic insight on the cellular and molecular mechanisms of its action.
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Setiawan I, Blanchard GJ. Ethanol-induced perturbations to planar lipid bilayer structures. J Phys Chem B 2014; 118:537-46. [PMID: 24372563 DOI: 10.1021/jp410305m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We report on the formation of planar lipid bilayer structures on mica where the bilayer contains the phosphocholine 1,2-dioleoyl-sn-phosphatidylcholine (DOPC), cholesterol, sphingomyelin and sulforhodamine-tagged-1,2-dioleoyl-sn-phosphatidylethanolamine (SR-DOPE). Phase separation is seen for the cholesterol domains within the bilayer structure, and exposure of this supported bilayer to controlled concentrations of ethanol reveals organizational changes on both the micrometer- and molecular-length scales. We report steady state fluorescence imaging, fluorescence lifetime imaging, and fluorescence anisotropy decay imaging for these bilayers. These data are complementary to existing information on the interactions of lipid bilayers with ethanol and point to subtle but important changes in the molecular-scale organization of these structures.
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Affiliation(s)
- Iwan Setiawan
- Department of Chemistry, Michigan State University , 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
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Effect of acetone accumulation on structure and dynamics of lipid membranes studied by molecular dynamics simulations. Comput Biol Chem 2013; 46:23-31. [DOI: 10.1016/j.compbiolchem.2013.04.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 04/27/2013] [Accepted: 04/29/2013] [Indexed: 12/30/2022]
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Kurniawan Y, Scholz C, Bothun GD. n-Butanol partitioning into phase-separated heterogeneous lipid monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:10817-10823. [PMID: 23888902 DOI: 10.1021/la400977h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Cellular adaptation to elevated alcohol concentration involves altering membrane lipid composition to counteract fluidization. However, few studies have examined the biophysical response of biologically relevant heterogeneous membranes. Lipid phase behavior, molecular packing, and elasticity have been examined by surface pressure-area (π-A) analysis in mixed monolayers composed of saturated dipalmitoylphosphatidylcholine (DPPC) and unsaturated dioleoylphosphatidylcholine (DOPC) as a function of DOPC and n-butanol concentration. n-Butanol partitioning into DPPC monolayers led to lipid expansion and increased elasticity. Greater lipid expansion occurred with increasing DOPC concentration, and a maximum was observed at equimolar DPPC:DOPC consistent with n-butanol partitioning between coexisting liquid expanded (LE, DOPC) phases and liquid condensed (LC, DPPC) domains. This led to distinct changes in the size and morphology of LC domains. In DOPC-rich monolayers the effect of n-butanol adsorption on π-A behavior was less pronounced due to DOPC tail kinking. These results point to the importance of lipid composition and phase coexistence on n-butanol partitioning and monolayer restructuring.
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Affiliation(s)
- Yogi Kurniawan
- Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Rd., Kingston, Rhode Island 02881, United States
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Zhan H, Lazaridis T. Inclusion of lateral pressure/curvature stress effects in implicit membrane models. Biophys J 2013; 104:643-54. [PMID: 23442915 DOI: 10.1016/j.bpj.2012.12.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/06/2012] [Accepted: 12/10/2012] [Indexed: 02/06/2023] Open
Abstract
Implicit membrane models usually treat the membrane as a hydrophobic slab and neglect lateral pressure/curvature stress effects. As a result, they cannot distinguish, for example, PE from PC lipids. Here, the implicit membrane model IMM1 is extended to include these effects using a combination of classical thermodynamics and membrane elasticity theory. The proposed model is tested by molecular dynamics simulation of the peptides alamethicin, melittin, cyclotide kalata B1, 18A, and KKpL15. The lateral pressure term stabilizes interfacial binding due to the negative pressure at the hydrocarbon-water interface. In agreement with experiment, increase in the peptide/lipid molar ratio shifts the equilibrium from the interfacial to the transmembrane orientation. Simulations of mixed DOPC/DOPE bilayers show that increase of the DOPE mole fraction in general stabilizes interfacial orientations and destabilizes transmembrane orientations. The extent of the stabilization or destabilization varies depending on the exact position of the peptides. The computational results are in good agreement with experiments.
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Affiliation(s)
- Huan Zhan
- Department of Chemistry, City College of New York/City University of New York, New York, New York, USA
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41
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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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Abstract
Volatile anesthetics serve as useful probes of a conserved biological process that is essential to the proper functioning of the central nervous system. A kinetic and thermodynamic analysis of their unusual pharmacological and physiological characteristics has led to a general, predictive theory in which small molecules that adsorb to membranes modulate ion channel function by altering physical properties of membrane bilayers. A kinetic model that is both parsimonious and falsifiable has been developed to test this mechanism. This theory leads to predictions about the structure, function, origin, and evolution of synapses, the etiology of several diseases and disease symptoms affecting the brain, and the mechanism of action of several drugs that are used therapeutically. Neuronal membranes may offer an appealing drug target, given the large number of compounds that adsorb to interfaces and hence membranes.
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Affiliation(s)
- James M Sonner
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, California 94143-0464, USA.
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Tian K, Li H, Ye S. Methanol Perturbing Modeling Cell Membranes Investigated using Linear and Nonlinear Vibrational Spectroscopy. CHINESE J CHEM PHYS 2013. [DOI: 10.1063/1674-0068/26/01/27-34] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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44
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Booker RD, Sum AK. Biophysical changes induced by xenon on phospholipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1347-56. [PMID: 23376329 DOI: 10.1016/j.bbamem.2013.01.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 12/28/2012] [Accepted: 01/22/2013] [Indexed: 12/20/2022]
Abstract
Structural and dynamic changes in cell membrane properties induced by xenon, a volatile anesthetic molecule, may affect the function of membrane-mediated proteins, providing a hypothesis for the mechanism of general anesthetic action. Here, we use molecular dynamics simulation and differential scanning calorimetry to examine the biophysical and thermodynamic effects of xenon on model lipid membranes. Our results indicate that xenon atoms preferentially localize in the hydrophobic core of the lipid bilayer, inducing substantial increases in the area per lipid and bilayer thickness. Xenon depresses the membrane gel-liquid crystalline phase transition temperature, increasing membrane fluidity and lipid head group spacing, while inducing net local ordering effects in a small region of the lipid carbon tails and modulating the bilayer lateral pressure profile. Our results are consistent with a role for nonspecific, lipid bilayer-mediated mechanisms in producing xenon's general anesthetic action.
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Affiliation(s)
- Ryan D Booker
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
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45
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Jämbeck JPM, Lyubartsev AP. Implicit inclusion of atomic polarization in modeling of partitioning between water and lipid bilayers. Phys Chem Chem Phys 2013; 15:4677-86. [DOI: 10.1039/c3cp44472d] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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46
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Polley A, Vemparala S. Partitioning of ethanol in multi-component membranes: Effects on membrane structure. Chem Phys Lipids 2013; 166:1-11. [DOI: 10.1016/j.chemphyslip.2012.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 11/23/2012] [Accepted: 11/24/2012] [Indexed: 12/12/2022]
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47
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Maftouni N, Amininasab M, Vali M, Ejtehadi M, Kowsari F. A Molecular Dynamics Simulation Study of Nanomechanical Properties of Asymmetric Lipid Bilayer. J Membr Biol 2012; 246:67-73. [DOI: 10.1007/s00232-012-9505-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 09/19/2012] [Indexed: 11/30/2022]
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Yamamoto E, Akimoto T, Shimizu H, Hirano Y, Yasui M, Yasuoka K. Diffusive nature of xenon anesthetic changes properties of a lipid bilayer: molecular dynamics simulations. J Phys Chem B 2012; 116:8989-95. [PMID: 22715916 DOI: 10.1021/jp303330c] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Effects of general anesthesia can be controllable by the ambient pressure. We perform molecular dynamics simulations for a 1-palmitoyl-2-oleoyl phosphatidylethanolamine lipid bilayer with or without xenon molecules by changing the pressure to elucidate the mechanism of the pressure reversal of general anesthesia. According to the diffusive nature of xenon molecules in the lipid bilayer, a decrease in the orientational order of the lipid tails, an increase in the area and volume per lipid molecule, and an increase in the diffusivity of lipid molecules are observed. We show that the properties of the lipid bilayer with xenon molecules at high pressure come close to those without xenon molecules at 0.1 MPa. Furthermore, we find that xenon molecules are concentrated in the middle of the lipid bilayer at high pressures by the pushing effect and that the diffusivity of xenon molecules is suppressed. These results suggest that the pressure reversal originates from a jamming and suppression of the diffusivity of xenon molecules in lipid bilayers.
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Affiliation(s)
- Eiji Yamamoto
- Department of Mechanical Engineering, Keio University, 3-4-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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Orłowski A, Grzybek M, Bunker A, Pasenkiewicz-Gierula M, Vattulainen I, Männistö PT, Róg T. Strong preferences of dopamine and l-dopa towards lipid head group: importance of lipid composition and implication for neurotransmitter metabolism. J Neurochem 2012; 122:681-90. [DOI: 10.1111/j.1471-4159.2012.07813.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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50
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Kurniawan Y, Venkataramanan KP, Scholz C, Bothun GD. n-Butanol Partitioning and Phase Behavior in DPPC/DOPC Membranes. J Phys Chem B 2012; 116:5919-24. [DOI: 10.1021/jp301340k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yogi Kurniawan
- Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Rd, Kingston,
Rhode Island 02881, United States
| | - Keerthi P. Venkataramanan
- Biotechnology Science and Engineering
program, University of Alabama in Huntsville, 301 Sparkman Dr., Huntsville, Alabama 35899, United States
| | - Carmen Scholz
- Department of Chemistry, University of Alabama in Huntsville, 301 Sparkman Dr.,
Huntsville, Alabama 35899, United States
| | - Geoffrey D. Bothun
- Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Rd, Kingston,
Rhode Island 02881, United States
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