1
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Szomek M, Akkerman V, Lauritsen L, Walther HL, Juhl AD, Thaysen K, Egebjerg JM, Covey DF, Lehmann M, Wessig P, Foster AJ, Poolman B, Werner S, Schneider G, Müller P, Wüstner D. Ergosterol promotes aggregation of natamycin in the yeast plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184350. [PMID: 38806103 DOI: 10.1016/j.bbamem.2024.184350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 05/11/2024] [Accepted: 05/24/2024] [Indexed: 05/30/2024]
Abstract
Polyene macrolides are antifungal substances, which interact with cells in a sterol-dependent manner. While being widely used, their mode of action is poorly understood. Here, we employ ultraviolet-sensitive (UV) microscopy to show that the antifungal polyene natamycin binds to the yeast plasma membrane (PM) and causes permeation of propidium iodide into cells. Right before membrane permeability became compromised, we observed clustering of natamycin in the PM that was independent of PM protein domains. Aggregation of natamycin was paralleled by cell deformation and membrane blebbing as revealed by soft X-ray microscopy. Substituting ergosterol for cholesterol decreased natamycin binding and caused a reduced clustering of natamycin in the PM. Blocking of ergosterol synthesis necessitates sterol import via the ABC transporters Aus1/Pdr11 to ensure natamycin binding. Quantitative imaging of dehydroergosterol (DHE) and cholestatrienol (CTL), two analogues of ergosterol and cholesterol, respectively, revealed a largely homogeneous lateral sterol distribution in the PM, ruling out that natamycin binds to pre-assembled sterol domains. Depletion of sphingolipids using myriocin increased natamycin binding to yeast cells, likely by increasing the ergosterol fraction in the outer PM leaflet. Importantly, binding and membrane aggregation of natamycin was paralleled by a decrease of the dipole potential in the PM, and this effect was enhanced in the presence of myriocin. We conclude that ergosterol promotes binding and aggregation of natamycin in the yeast PM, which can be synergistically enhanced by inhibitors of sphingolipid synthesis.
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Affiliation(s)
- Maria Szomek
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Vibeke Akkerman
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Line Lauritsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Hanna-Loisa Walther
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Alice Dupont Juhl
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Katja Thaysen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Jacob Marcus Egebjerg
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Douglas F Covey
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, MO 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, USA
| | - Max Lehmann
- Institute for Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany
| | - Pablo Wessig
- Institute for Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany
| | - Alexander J Foster
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 Groningen, the Netherlands
| | - Bert Poolman
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 Groningen, the Netherlands
| | - Stephan Werner
- Department of X-Ray Microscopy, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Gerd Schneider
- Department of X-Ray Microscopy, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Peter Müller
- Department of Biology, Humboldt University Berlin, Invalidenstr. 43, D-10115 Berlin, Germany
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
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2
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Clarke RJ. Biophysical Reviews' "Meet the Editors Series": a profile of Ronald Clarke. Biophys Rev 2024; 16:145-148. [PMID: 38737205 PMCID: PMC11078904 DOI: 10.1007/s12551-024-01187-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2024] [Indexed: 05/14/2024] Open
Abstract
This article of the continuing "Biophysical Reviews Meet the Editors Series" introduces Ronald Clarke, biophysical chemist, member of the Biophysical Reviews editorial board and current Secretary-General of the International Union of Pure and Applied Biophysics (IUPAB).
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Affiliation(s)
- Ronald J. Clarke
- School of Chemistry, University of Sydney, Sydney, NSW 2006 Australia
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3
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Cejas JDP, Rosa AS, González Paz AN, Disalvo EA, Frías MDLA. Impact of chlorogenic acid on surface and phase properties of cholesterol-enriched phosphatidylcholine membranes. Arch Biochem Biophys 2024; 753:109913. [PMID: 38286353 DOI: 10.1016/j.abb.2024.109913] [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: 10/13/2023] [Revised: 11/26/2023] [Accepted: 01/25/2024] [Indexed: 01/31/2024]
Abstract
This study analyses the insertion of Chlorogenic acid (CGA) in phosphatidylcholine (PC) membranes enriched with cholesterol (Chol). While cholesterol decreases the area per lipid and increases the dipole potential, CGA increases and decreases these values, respectively. When CGA is inserted into cholesterol-containing DMPC membranes, these effects cancel out, resulting in values that overlap with those of DMPC monolayers without Chol and CGA. The presence of CGA also compensates the increase of dipole potential produced by Chol which can be explain as a consequence of the orientation of CGA molecule at the interphase opposing the cholesterol dipole moieties and water dipoles. This compensatory effect is less effective when lipids lack carbonyl groups (CO). When monolayers are composed by unsaturated PCs the Chol compensation is found at higher concentrations of CGA due to the direct interaction between CGA and Chol. These results suggest that cholesterol modulates the interaction and distribution of CGA in the lipid membrane, which may have implications for its biological activity.
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Affiliation(s)
- Jimena Del P Cejas
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofísica Aplicada y Alimentos, CIBAAL, National University of Santiago del Estero and CONICET), Laboratory of Biointerphases and Biomimetic Systems, RN 9 - Km 1125, 4206, Santiago del Estero, Argentina
| | - Antonio S Rosa
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofísica Aplicada y Alimentos, CIBAAL, National University of Santiago del Estero and CONICET), Laboratory of Biointerphases and Biomimetic Systems, RN 9 - Km 1125, 4206, Santiago del Estero, Argentina
| | - Agustín N González Paz
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofísica Aplicada y Alimentos, CIBAAL, National University of Santiago del Estero and CONICET), Laboratory of Biointerphases and Biomimetic Systems, RN 9 - Km 1125, 4206, Santiago del Estero, Argentina
| | - Edgardo A Disalvo
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofísica Aplicada y Alimentos, CIBAAL, National University of Santiago del Estero and CONICET), Laboratory of Biointerphases and Biomimetic Systems, RN 9 - Km 1125, 4206, Santiago del Estero, Argentina
| | - María de Los A Frías
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofísica Aplicada y Alimentos, CIBAAL, National University of Santiago del Estero and CONICET), Laboratory of Biointerphases and Biomimetic Systems, RN 9 - Km 1125, 4206, Santiago del Estero, Argentina.
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4
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Cavaglià M, Deriu MA, Tuszynski JA. Toward a holographic brain paradigm: a lipid-centric model of brain functioning. Front Neurosci 2023; 17:1302519. [PMID: 38161798 PMCID: PMC10757614 DOI: 10.3389/fnins.2023.1302519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 12/04/2023] [Indexed: 01/03/2024] Open
Abstract
Due to the stimulation of neuronal membrane dipoles by action potentials, under suitable conditions coherent dipole oscillations can be formed. We argue that these dipole oscillations satisfy the weak Bose-Einstein condensate criteria of the Froehlich model of biological coherence. They can subsequently generate electromagnetic fields (EMFs) propagating in the inter-neuronal space. When neighboring neurons fire synchronously, EMFs can create interference patterns and hence form holographic images containing analog information about the sensory inputs that trigger neuronal activity. The mirror pattern projected by EMFs inside the neuron can encode information in the neuronal cytoskeleton. We outline an experimental verification of our hypothesis and its consequences for anesthesia, neurodegenerative diseases, and psychiatric states.
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Affiliation(s)
| | | | - Jack A. Tuszynski
- DIMEAS, Politecnico di Torino, Turin, Italy
- Department of Data Science and Engineering, The Silesian University of Technology, Gliwice, Poland
- Department of Physics, University of Alberta, Edmonton, AB, Canada
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5
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Clarke RJ. Electrostatic switch mechanisms of membrane protein trafficking and regulation. Biophys Rev 2023; 15:1967-1985. [PMID: 38192346 PMCID: PMC10771482 DOI: 10.1007/s12551-023-01166-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 11/17/2023] [Indexed: 01/10/2024] Open
Abstract
Lipid-protein interactions are normally classified as either specific or general. Specific interactions refer to lipid binding to specific binding sites within a membrane protein, thereby modulating the protein's thermal stability or kinetics. General interactions refer to indirect effects whereby lipids affect membrane proteins by modulating the membrane's physical properties, e.g., its fluidity, thickness, or dipole potential. It is not widely recognized that there is a third distinct type of lipid-protein interaction. Intrinsically disordered N- or C-termini of membrane proteins can interact directly but nonspecifically with the surrounding membrane. Many peripheral membrane proteins are held to the cytoplasmic surface of the plasma membrane via a cooperative combination of two forces: hydrophobic anchoring and electrostatic attraction. An acyl chain, e.g., myristoyl, added post-translationally to one of the protein's termini inserts itself into the lipid matrix and helps hold peripheral membrane proteins onto the membrane. Electrostatic attraction occurs between positively charged basic amino acid residues (lysine and arginine) on one of the protein's terminal tails and negatively charged phospholipid head groups, such as phosphatidylserine. Phosphorylation of either serine or tyrosine residues on the terminal tails via regulatory protein kinases allows for an electrostatic switch mechanism to control trafficking of the protein. Kinase action reduces the positive charge on the protein's tail, weakening the electrostatic attraction and releasing the protein from the membrane. A similar mechanism regulates many integral membrane proteins, but here only electrostatic interactions are involved, and the electrostatic switch modulates protein activity by altering the stabilities of different protein conformational states.
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Affiliation(s)
- Ronald J. Clarke
- School of Chemistry, University of Sydney, Sydney, NSW 2006 Australia
- The University of Sydney Nano Institute, Sydney, NSW 2006 Australia
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6
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Lev B, Chennath M, Cranfield CG, Cornelius F, Allen TW, Clarke RJ. Involvement of the alpha-subunit N-terminus in the mechanism of the Na +,K +-ATPase. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119539. [PMID: 37479188 DOI: 10.1016/j.bbamcr.2023.119539] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/26/2023] [Accepted: 07/10/2023] [Indexed: 07/23/2023]
Abstract
Previous studies have shown that cytoplasmic K+ release and the associated E2 → E1 conformational change of the Na+,K+-ATPase is a major rate-determining step of the enzyme's ion pumping cycle and hence a prime site of acute regulatory intervention. From the ionic strength dependence of the enzyme's distribution between the E2 and E1 states, it has also been found that E2 is stabilized by an electrostatic attraction. Any disruption of this electrostatic attraction would, thus, have profound effects on the rate of ion pumping. The aim of this paper is to identify the location of this interaction. Using enhanced-sampling molecular dynamics simulations with a predicted N-terminal structure added to the X-ray crystal structure of the Na+,K+-ATPase, a previously postulated salt bridge between Lys32 and Glu233 (rat sequence numbering) of the enzyme's α-subunit can be excluded. The residues never approach closely enough to form a salt bridge. In contrast, strong interactions with anionic lipid head groups were seen. To investigate the possibility of a protein-lipid interaction experimentally, the surface charge density of Na+,K+-ATPase-containing membrane fragments was estimated from zeta potential measurements to be 0.019 (± 0.001) C m-2. This is in good agreement with the charge density previously determined to be responsible for stabilization of the E2 state of 0.023 (± 0.009) C m-2 and the membrane charge density estimated here from published electron-microscopic images of 0.018C m-2. The results are, therefore, consistent with an interaction of the Na+,K+-ATPase α-subunit N-terminus with negatively-charged lipid head groups of the neighbouring cytoplasmic membrane surface as the origin of the electrostatic interaction stabilising the E2 state.
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Affiliation(s)
- B Lev
- School of Science, RMIT University, Melbourne, Vic, 3001, Australia
| | - M Chennath
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - C G Cranfield
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - F Cornelius
- Department of Biomedicine, University of Aarhus, DK-8000 Aarhus, C, Denmark
| | - T W Allen
- School of Science, RMIT University, Melbourne, Vic, 3001, Australia
| | - R J Clarke
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia; The University of Sydney Nano Institute, Sydney, NSW 2006, Australia.
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7
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Youngworth R, Roux B. Simulating the Voltage-Dependent Fluorescence of Di-8-ANEPPS in a Lipid Membrane. J Phys Chem Lett 2023; 14:8268-8276. [PMID: 37676243 PMCID: PMC10510438 DOI: 10.1021/acs.jpclett.3c01257] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/25/2023] [Indexed: 09/08/2023]
Abstract
Voltage-sensitive fluorescent dyes such as di-8-ANEPPS (di-8-aminonaphthylethylenepyridinium propylsulfonate) are powerful tools to study biological membranes. Its fluorescence is affected by changes in the membrane potential and other factors, requiring extensive calibration to extract meaningful quantitative results. The amphiphilic di-8-ANEPPS molecule is expected to bind at the membrane-solution interface. However, atomic-level information is sparse about its position and orientation in the membrane, especially in regards to how the latter dynamically fluctuates to affect the observed fluorescence. In the present work, molecular dynamics simulations of the ground and excited states of di-8-ANEPPS embedded in a DPPC membrane as represented by classical force fields were used to investigate how the fluorescence is affected by externally applied potential. The calculations reproduce the shifts in the wavelength of emission as a function of voltage that are observed experimentally, indicating that the approach can help better understand the various factors that can affect the fluorescence of membrane-bound dyes.
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Affiliation(s)
- Rachael Youngworth
- Department
of Chemistry, The University of Chicago, 5735 S. Ellis Avenue, Chicago, Illinois 60637, United States
| | - Benoît Roux
- Department
of Biochemistry and Molecular Biology, The
University of Chicago, 929 E. 57th Street W225, Chicago, Illinois 60637, United States
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8
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Valorphins alter physicochemical characteristics of phosphatidylcholine membranes: datasets on lipid packing, bending rigidity, specific electrical capacitance, dipole potential, vesicle size. Data Brief 2022; 45:108716. [DOI: 10.1016/j.dib.2022.108716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
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9
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Sarkar P, Chattopadhyay A. Membrane Dipole Potential: An Emerging Approach to Explore Membrane Organization and Function. J Phys Chem B 2022; 126:4415-4430. [PMID: 35696090 DOI: 10.1021/acs.jpcb.2c02476] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biological membranes are complex organized molecular assemblies of lipids and proteins that provide cells and membrane-bound intracellular organelles their individual identities by morphological compartmentalization. Membrane dipole potential originates from the electrostatic potential difference within the membrane due to the nonrandom arrangement (orientation) of amphiphile and solvent (water) dipoles at the membrane interface. In this Feature Article, we will focus on the measurement of dipole potential using electrochromic fluorescent probes and highlight interesting applications. In addition, we will focus on ratiometric fluorescence microscopic imaging technique to measure dipole potential in cellular membranes, a technique that can be used to address novel problems in cell biology which are otherwise difficult to address using available approaches. We envision that membrane dipole potential could turn out to be a convenient tool in exploring the complex interplay between membrane lipids and proteins and could provide novel insights in membrane organization and function.
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Affiliation(s)
- Parijat Sarkar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
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10
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Lee E, You X, Baiz CR. Interfacial dynamics in inverted-headgroup lipid membranes. J Chem Phys 2022; 156:075102. [PMID: 35183070 PMCID: PMC8858029 DOI: 10.1063/5.0080153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Inverted-headgroup (choline-phosphate) lipids are synthetic lipids that are not found in nature and are used as model systems to understand the role of headgroup dipole orientation. Recently, studies revealed that the net orientation of interfacial water strongly depends on the headgroup electrostatics, i.e., the charges and dipole generated by the phosphate and the choline groups. In order to characterize interfacial H-bond dynamics, we measured two-dimensional infrared spectra of the ester carbonyl band and performed molecular dynamics simulations in fully hydrated 1,2-dioleoyl-sn-glycero-3-phosphocholine and 2-((2,3-bis(oleoyloxy)propyl)-dimethyl-ammonio)ethyl ethyl phosphate (DOCPe) lipid bilayers. The experiments and simulations suggest that the reverse dipole generated by the inverted-headgroup in DOCPe does not affect the carbonyl H-bond populations or the interfacial water H-bond dynamics. However, while phosphate-associated waters in both lipids appear to show a similar H-bond structure, carbonyl-associated waters are characterized by a slightly disrupted H-bond structure in the DOCPe bilayer, especially within the second hydration shell. Our findings show that changes in net water orientation perturb the water H-bonds at the linker region between the headgroup and the lipid tail, although this perturbation is weak.
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11
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Vitkova V, Yordanova V, Staneva G, Petkov O, Stoyanova-Ivanova A, Antonova K, Popkirov G. Dielectric Properties of Phosphatidylcholine Membranes and the Effect of Sugars. MEMBRANES 2021; 11:membranes11110847. [PMID: 34832076 PMCID: PMC8623822 DOI: 10.3390/membranes11110847] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022]
Abstract
Simple carbohydrates are associated with the enhanced risk of cardiovascular disease and adverse changes in lipoproteins in the organism. Conversely, sugars are known to exert a stabilizing effect on biological membranes, and this effect is widely exploited in medicine and industry for cryopreservation of tissues and materials. In view of elucidating molecular mechanisms involved in the interaction of mono- and disaccharides with biomimetic lipid systems, we study the alteration of dielectric properties, the degree of hydration, and the rotational order parameter and dipole potential of lipid bilayers in the presence of sugars. Frequency-dependent deformation of cell-size unilamellar lipid vesicles in alternating electric fields and fast Fourier transform electrochemical impedance spectroscopy are applied to measure the specific capacitance of phosphatidylcholine lipid bilayers in sucrose, glucose and fructose aqueous solutions. Alteration of membrane specific capacitance is reported in sucrose solutions, while preservation of membrane dielectric properties is established in the presence of glucose and fructose. We address the effect of sugars on the hydration and the rotational order parameter for 1-palmitoyl-2-oleoyl-sn-glycero-3- phosphocholine (POPC) and 1-stearoyl-2-oleoyl-sn-glycero-3- phosphocholine (SOPC). An increased degree of lipid packing is reported in sucrose solutions. The obtained results provide evidence that some small carbohydrates are able to change membrane dielectric properties, structure, and order related to membrane homeostasis. The reported data are also relevant to future developments based on the response of lipid bilayers to external physical stimuli such as electric fields and temperature changes.
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Affiliation(s)
- Victoria Vitkova
- Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Blvd., 1784 Sofia, Bulgaria; (O.P.); (A.S.-I.); (K.A.)
- Correspondence:
| | - Vesela Yordanova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria; (V.Y.); (G.S.)
| | - Galya Staneva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria; (V.Y.); (G.S.)
| | - Ognyan Petkov
- Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Blvd., 1784 Sofia, Bulgaria; (O.P.); (A.S.-I.); (K.A.)
| | - Angelina Stoyanova-Ivanova
- Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Blvd., 1784 Sofia, Bulgaria; (O.P.); (A.S.-I.); (K.A.)
| | - Krassimira Antonova
- Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Blvd., 1784 Sofia, Bulgaria; (O.P.); (A.S.-I.); (K.A.)
| | - Georgi Popkirov
- Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Blvd., 1784 Sofia, Bulgaria;
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12
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de Matos AM, Blázquez-Sánchez MT, Sousa C, Oliveira MC, de Almeida RFM, Rauter AP. C-Glucosylation as a tool for the prevention of PAINS-induced membrane dipole potential alterations. Sci Rep 2021; 11:4443. [PMID: 33627687 PMCID: PMC7904931 DOI: 10.1038/s41598-021-83032-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 01/18/2021] [Indexed: 12/13/2022] Open
Abstract
The concept of Pan-Assay Interference Compounds (PAINS) is regarded as a threat to the recognition of the broad bioactivity of natural products. Based on the established relationship between altered membrane dipole potential and transmembrane protein conformation and function, we investigate here polyphenols' ability to induce changes in cell membrane dipole potential. Ultimately, we are interested in finding a tool to prevent polyphenol PAINS-type behavior and produce compounds less prone to untargeted and promiscuous interactions with the cell membrane. Di-8-ANEPPS fluorescence ratiometric measurements suggest that planar lipophilic polyphenols-phloretin, genistein and resveratrol-act by decreasing membrane dipole potential, especially in cholesterol-rich domains such as lipid rafts, which play a role in important cellular processes. These results provide a mechanism for their labelling as PAINS through their ability to disrupt cell membrane homeostasis. Aiming to explore the role of C-glucosylation in PAINS membrane-interfering behavior, we disclose herein the first synthesis of 4-glucosylresveratrol, starting from 5-hydroxymethylbenzene-1,3-diol, via C-glucosylation, oxidation and Horner-Wadsworth-Emmons olefination, and resynthesize phloretin and genistein C-glucosides. We show that C-glucosylation generates compounds which are no longer able to modify membrane dipole potential. Therefore, it can be devised as a strategy to generate bioactive natural product derivatives that no longer act as membrane dipole potential modifiers. Our results offer a new technology towards rescuing bioactive polyphenols from their PAINS danger label through C-C ligation of sugars.
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Affiliation(s)
- Ana Marta de Matos
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016, Lisboa, Portugal
| | - Maria Teresa Blázquez-Sánchez
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016, Lisboa, Portugal
- Facultad de Ciencias y Artes, Universidad Católica Santa Teresa de Jesús de Ávila (UCAV), 05005, Avila, Spain
| | - Carla Sousa
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016, Lisboa, Portugal
| | - Maria Conceição Oliveira
- Centro de Química Estrutural, Instituto Superior Técnico, Mass Spectrometry Facility, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
| | - Rodrigo F M de Almeida
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016, Lisboa, Portugal.
| | - Amélia P Rauter
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016, Lisboa, Portugal.
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Sánchez-López E, Esteruelas G, Ortiz A, Espina M, Prat J, Muñoz M, Cano A, Calpena AC, Ettcheto M, Camins A, Alsafi Z, Souto EB, García ML, Pujol M. Dexibuprofen Biodegradable Nanoparticles: One Step Closer towards a Better Ocular Interaction Study. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E720. [PMID: 32290252 PMCID: PMC7221783 DOI: 10.3390/nano10040720] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/30/2020] [Accepted: 04/04/2020] [Indexed: 02/08/2023]
Abstract
Ocular inflammation is one of the most prevalent diseases in ophthalmology, which can affect various parts of the eye or the surrounding tissues. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, are commonly used to treat ocular inflammation in the form of eye-drops. However, their bioavailability in ocular tissues is very low (less than 5%). Therefore, drug delivery systems such as biodegradable polymeric PLGA nanoparticles constitute a suitable alternative to topical eye administration, as they can improve ocular bioavailability and simultaneously reduce drug induced side effects. Moreover, their prolonged drug release can enhance patient treatment adherence as they require fewer administrations. Therefore, several formulations of PLGA based nanoparticles encapsulating dexibuprofen (active enantiomer of Ibuprofen) were prepared using the solvent displacement method employing different surfactants. The formulations have been characterized and their interactions with a customized lipid corneal membrane model were studied. Ex vivo permeation through ocular tissues and in vivo anti-inflammatory efficacy have also been studied.
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Affiliation(s)
- Elena Sánchez-López
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED), Carlos III Health Institute, 28031 Madrid, Spain; (M.E.); (A.C.)
| | - Gerard Esteruelas
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
| | - Alba Ortiz
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Marta Espina
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Josefina Prat
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Montserrat Muñoz
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Amanda Cano
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED), Carlos III Health Institute, 28031 Madrid, Spain; (M.E.); (A.C.)
| | - Ana Cristina Calpena
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Miren Ettcheto
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED), Carlos III Health Institute, 28031 Madrid, Spain; (M.E.); (A.C.)
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain
| | - Antoni Camins
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED), Carlos III Health Institute, 28031 Madrid, Spain; (M.E.); (A.C.)
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain
| | - Zaid Alsafi
- Glaucoma and Retinal Neurodegeneration Research Visual Neuroscience, UCL Institute of Ophthalmology, Bath Street, London EC1V 9EL, UK;
| | - Eliana B. Souto
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal;
- CEB—Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Maria Luisa García
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED), Carlos III Health Institute, 28031 Madrid, Spain; (M.E.); (A.C.)
| | - Montserrat Pujol
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain; (G.E.); (A.O.); (M.E.); (J.P.); (M.M.); (A.C.); (A.C.C.); (M.L.G.); (M.P.)
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, 08028 Barcelona, Spain
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14
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Pérez HA, Cejas JP, Rosa AS, Giménez RE, Disalvo EA, Frías MA. Modulation of Interfacial Hydration by Carbonyl Groups in Lipid Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2644-2653. [PMID: 32073276 DOI: 10.1021/acs.langmuir.9b03551] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The lack of carbonyl groups and the presence of ether bonds give the lipid interphase a different water organization around the phosphate groups that affects the compressibility and electrical properties of lipid membranes. Generalized polarization of 1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (14:0 diether PC) in correlation with Fourier transform infrared (FTIR) analysis indicates a higher level of polarizability of water molecules in the membrane phase around the phosphate groups both below and above Tm. This reorganization of water promotes a different response in compressibility and dipole moment of the interphase, which is related to different H bonding of water molecules with phosphates (PO) and carbonyl (CO) groups.
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Affiliation(s)
- H A Pérez
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL), National University of Santiago del Estero and CONICET, RN 9, Km 1125, 4206 Santiago del Estero, Argentina
| | - J P Cejas
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL), National University of Santiago del Estero and CONICET, RN 9, Km 1125, 4206 Santiago del Estero, Argentina
| | - A S Rosa
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL), National University of Santiago del Estero and CONICET, RN 9, Km 1125, 4206 Santiago del Estero, Argentina
| | - R E Giménez
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL), National University of Santiago del Estero and CONICET, RN 9, Km 1125, 4206 Santiago del Estero, Argentina
| | - E A Disalvo
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL), National University of Santiago del Estero and CONICET, RN 9, Km 1125, 4206 Santiago del Estero, Argentina
| | - M A Frías
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL), National University of Santiago del Estero and CONICET, RN 9, Km 1125, 4206 Santiago del Estero, Argentina
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15
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Shen H, Zhao K, Wu Z. Effects of Ether Linkage on Membrane Dipole Potential and Cholesterol Flip-Flop Motion in Lipid Bilayer Membranes. J Phys Chem B 2019; 123:7818-7828. [DOI: 10.1021/acs.jpcb.9b06570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hujun Shen
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University No.115, Gaoxin Road, Guiyang, Guizhou 550018, P. R. China
- Guizhou University of Finance and Economics, School of Information, University City of Huaxi District, Guiyang, Guizhou 550025, P. R. China
| | - Kun Zhao
- Guizhou University of Finance and Economics, School of Information, University City of Huaxi District, Guiyang, Guizhou 550025, P. R. China
| | - Zhenhua Wu
- Guizhou University of Finance and Economics, School of Information, University City of Huaxi District, Guiyang, Guizhou 550025, P. R. China
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16
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Garcia A, Pochinda S, Elgaard-Jørgensen PN, Khandelia H, Clarke RJ. Evidence for ATP Interaction with Phosphatidylcholine Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:9944-9953. [PMID: 31291108 DOI: 10.1021/acs.langmuir.9b01240] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
ATP is a fundamental intracellular molecule and is thought to diffuse freely throughout the cytosol. Evidence obtained from nucleotide-sensing sarcolemmal ion channels and red blood cells, however, suggest that ATP is compartmentalized or buffered, especially beneath the sarcolemma, but no definitive mechanism for restricted diffusion or potential buffering system has been postulated. In this study, we provide evidence from alterations to membrane dipole potential, membrane conductance, changes in enthalpy of phospholipid phase transition, and from free energy calculations that ATP associates with phospholipid bilayers. Furthermore, all-atom molecular dynamics simulations show that ATP can form aggregates in the aqueous phase at high concentrations. ATP interaction with membranes provides a new model to understand the diffusion of ATP through the cell. Coupled with previous reports of diffusion restriction in the subsarcolemmal space, these findings support the existence of compartmentalized or buffered pools of ATP.
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Affiliation(s)
- Alvaro Garcia
- School of Life Sciences , University of Technology Sydney , Ultimo , NSW 2007 , Australia
| | - Simon Pochinda
- PHYLIFE: Physical Life Sciences at SDU, Department of Physics, Chemistry and Pharmacy and MEMPHYS: Center for Biomembrane Physics , University of Southern Denmark , DK-5230 Odense M , Denmark
| | - Paninnguaq N Elgaard-Jørgensen
- PHYLIFE: Physical Life Sciences at SDU, Department of Physics, Chemistry and Pharmacy and MEMPHYS: Center for Biomembrane Physics , University of Southern Denmark , DK-5230 Odense M , Denmark
| | - Himanshu Khandelia
- PHYLIFE: Physical Life Sciences at SDU, Department of Physics, Chemistry and Pharmacy and MEMPHYS: Center for Biomembrane Physics , University of Southern Denmark , DK-5230 Odense M , Denmark
| | - Ronald J Clarke
- School of Chemistry , University of Sydney , Sydney , NSW 2006 , Australia
- The University of Sydney Nano Institute , Sydney , NSW 2006 , Australia
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17
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Leonard AN, Wang E, Monje-Galvan V, Klauda JB. Developing and Testing of Lipid Force Fields with Applications to Modeling Cellular Membranes. Chem Rev 2019; 119:6227-6269. [DOI: 10.1021/acs.chemrev.8b00384] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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18
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Effect of Cholesterol on the Dipole Potential of Lipid Membranes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1115:135-154. [DOI: 10.1007/978-3-030-04278-3_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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19
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Sapoń K, Janas T, Janas T. Biophysical Characterization of Polysialic Acid—Membrane Nanosystems. SERIES IN BIOENGINEERING 2019. [DOI: 10.1007/978-981-13-0989-2_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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20
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Gomes B, Gonçalves S, Disalvo A, Hollmann A, Santos NC. Effect of 25-hydroxycholesterol in viral membrane fusion: Insights on HIV inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1171-1178. [PMID: 29408450 DOI: 10.1016/j.bbamem.2018.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/08/2018] [Accepted: 02/01/2018] [Indexed: 12/15/2022]
Abstract
Recently, it was demonstrated that 25-hydroxycholesterol (25HC), an oxidized cholesterol derivative, inhibits human immunodeficiency virus type 1 (HIV) entry into its target cells. However, the mechanisms involved in this action have not yet been established. The aim of this work was to study the effects of 25HC in biomembrane model systems and at the level of HIV fusion peptide (HIV-FP). Integration of different biophysical approaches was made in the context of HIV fusion process, to clarify the changes at membrane level due to the presence of 25HC that result in the suppressing of viral infection. Lipid vesicles mimicking mammalian and HIV membranes were used on spectroscopy assays and lipid monolayers in surface pressure studies. Peptide-induced lipid mixing assays were performed by Förster resonance energy transfer to calculate fusion efficiency. Liposome fusion is reduced by 50% in the presence of 25HC, comparatively to cholesterol. HIV-FP conformation was assessed by infrared assays and it relies on sterol nature. Anisotropy, surface pressure and dipole potential assays indicate that the conversion of cholesterol in 25HC leads to a loss of the cholesterol modulating effect on the membrane. With different biophysical techniques, we show that 25HC affects the membrane fusion process through the modification of lipid membrane properties, and by direct alterations on HIV-FP structure. The present data support a broad antiviral activity for 25HC.
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Affiliation(s)
- Bárbara Gomes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Sónia Gonçalves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Anibal Disalvo
- Laboratory of Biointerfaces and Biomimetic Systems, CITSE, University of Santiago del Estero, -CONICET, 4200 Santiago del Estero, Argentina
| | - Axel Hollmann
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal; Laboratory of Biointerfaces and Biomimetic Systems, CITSE, University of Santiago del Estero, -CONICET, 4200 Santiago del Estero, Argentina; Laboratory of Molecular Microbiology, Institute of Basic and Applied Microbiology, University of Quilmes, B1876BXD Bernal, Argentina
| | - Nuno C Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal.
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21
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Stereospecific Interactions of Cholesterol in a Model Cell Membrane: Implications for the Membrane Dipole Potential. J Membr Biol 2018; 251:507-519. [DOI: 10.1007/s00232-018-0016-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 01/25/2018] [Indexed: 12/11/2022]
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22
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Efimova SS, Zakharova AA, Ismagilov AA, Schagina LV, Malev VV, Bashkirov PV, Ostroumova OS. Lipid-mediated regulation of pore-forming activity of syringomycin E by thyroid hormones and xanthene dyes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:691-699. [PMID: 29253504 DOI: 10.1016/j.bbamem.2017.12.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/21/2017] [Accepted: 12/13/2017] [Indexed: 10/18/2022]
Abstract
The effects of dipole modifiers, thyroid hormones (thyroxine and triiodothyronine) and xanthene dyes (Rose Bengal, phloxineB, erythrosin, eosinY and fluorescein) on the pore-forming activity of the lipopeptide syringomycin E (SRE) produced by Pseudomonas syringae were studied in a model bilayer. Thyroxine does not noticeably influence the steady-state number of open SRE channels (Nop), whereas triiodothyronine decreases it 10-fold at -50mV. Rose Bengal, phloxine B and erythrosin significantly increase Nop by 350, 100 and 70 times, respectively. Eosin Y and fluorescein do not practically affect the pore-forming activity of SRE. Recently, we showed that hormones decrease the dipole potential of lipid bilayers by approximately 60mV at 50μM, while Rose Bengal, phloxine B and erythrosin at 2.5μM reduce the membrane dipole potential by 120, 80 and 50mV, respectively. In the present study using differential scanning microcalorimetry, confocal fluorescence microscopy, the calcein release technique and measurements of membrane curvature elasticity, we show that triiodothyronine strongly affects the fluidity of model membranes: its addition leads to a significant decrease in the temperature and cooperativity of the main phase transition of DPPC, calcein leakage from DOPC vesicles, fluidization of solid domains in DOPC/DPPC liposomes, and promotion of lipid curvature stress. Thyroxine exerts a weaker effect. Xanthene dyes do not influence the phase transition of DPPC. Despite the decrease in the dipole potential, thyroid hormones modulate SRE channels predominantly via the elastic properties of the membrane, whereas the xanthene dyes Rose Bengal, phloxine B and erythrosine affect SRE channels via bilayer electrostatics.
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Affiliation(s)
- Svetlana S Efimova
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia.
| | | | - Artem A Ismagilov
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Ludmila V Schagina
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Valery V Malev
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia; St. Petersburg State University, Petergof 198504, Russia
| | - Pavel V Bashkirov
- Federal Research and Clinical Centre of Physical-Chemical Medicine, Moscow 119435, Russia
| | - Olga S Ostroumova
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
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23
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Cyboran-Mikołajczyk S, Żyłka R, Jurkiewicz P, Pruchnik H, Oszmiański J, Hof M, Kleszczyńska H. Interaction of procyanidin B 3 with membrane lipids – Fluorescence, DSC and FTIR studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1362-1371. [DOI: 10.1016/j.bbamem.2017.04.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 04/05/2017] [Accepted: 04/28/2017] [Indexed: 12/22/2022]
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24
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Wright AJ, Richens JL, Bramble JP, Cathcart N, Kitaev V, O'Shea P, Hudson AJ. Surface-enhanced Raman scattering measurement from a lipid bilayer encapsulating a single decahedral nanoparticle mediated by an optical trap. NANOSCALE 2016; 8:16395-16404. [PMID: 27722713 DOI: 10.1039/c6nr05616d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a new technique for the study of model membranes on the length-scale of a single nano-sized liposome. Silver decahedral nanoparticles have been encapsulated by a model unilamellar lipid bilayer creating nano-sized lipid vesicles. The metal core has two roles (i) increasing the polarizability of vesicles, enabling a single vesicle to be isolated and confined in an optical trap, and (ii) enhancing Raman scattering from the bilayer, via the high surface-plasmon field at the sharp vertices of the decahedral particles. Combined this has allowed us to measure a Raman fingerprint from a single vesicle of 50 nm-diameter, containing just ∼104 lipid molecules in a bilayer membrane over a surface area of <0.01 μm2, equivalent to a volume of approximately 1 zepto-litre. Raman scattering is a weak and inefficient process and previous studies have required either a substantially larger bilayer area in order to obtain a detectable signal, or the tagging of lipid molecules with a chromophore to provide an indirect probe of the bilayer. Our approach is fully label-free and bio-compatible and, in the future, it will enable much more localized studies of the heterogeneous structure of lipid bilayers and of membrane-bound components than is currently possible.
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Affiliation(s)
- A J Wright
- Department of Electrical and Electronic Engineering, University of Nottingham, Nottingham, NG7 2RD, UK.
| | - J L Richens
- Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC Canada, V6T 1Z3
| | - J P Bramble
- Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC Canada, V6T 1Z3
| | - N Cathcart
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada
| | - V Kitaev
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada
| | - P O'Shea
- Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC Canada, V6T 1Z3
| | - A J Hudson
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, UK
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25
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Local Anesthetics Affect Gramicidin A Channels via Membrane Electrostatic Potentials. J Membr Biol 2016; 249:781-787. [DOI: 10.1007/s00232-016-9926-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/24/2016] [Indexed: 10/21/2022]
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26
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Dipole-Potential-Mediated Effects on Ion Pump Kinetics. Biophys J 2016; 109:1513-20. [PMID: 26488640 DOI: 10.1016/j.bpj.2015.08.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 08/11/2015] [Accepted: 08/21/2015] [Indexed: 12/30/2022] Open
Abstract
The kinetics of conformational changes of P-type ATPases necessary for the occlusion or deocclusion of transported ions are known to be sensitive to the composition of the surrounding membrane, e.g., phospholipid content, mole percentage of cholesterol, and the presence of lipid-bound anions. Research has shown that many membrane components modify the dipole potential of the lipid head-group region. Based on the observation that occlusion/deocclusion reactions of ion pumps perturb the membrane surrounding the protein, a mechanism is suggested whereby dipole potential modifiers induce preferential stabilization or destabilization of occluded or nonoccluded states of the protein, leading to changes in the forward and backward rate constants for the transition. The mechanism relies on the assumption that conformational changes of the protein are associated with changes in its hydrophobic thickness that requires a change in local lipid packing density to allow hydrophobic matching with the membrane. The changes in lipid packing density cause changes in local lipid dipole potential that are responsible for the dependence of conformational kinetics on dipole potential modifiers. The proposed mechanism has the potential to explain effects of lipid composition on the kinetics of any membrane protein undergoing significant changes in its membrane cross-sectional area during its activity.
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27
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Jewell SA, Titball RW, Huyet J, Naylor CE, Basak AK, Gologan P, Winlove CP, Petrov PG. Clostridium perfringensα-toxin interaction with red cells and model membranes. SOFT MATTER 2015; 11:7748-7761. [PMID: 26303814 DOI: 10.1039/c5sm00876j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The effects of Clostridium perfringensα-toxin on host cells have previously been studied extensively but the biophysical processes associated with toxicity are poorly understood. The work reported here shows that the initial interaction between the toxin and lipid membrane leads to measurable changes in the physical properties and morphology of the membrane. A Langmuir monolayer technique was used to assess the response of different lipid species to toxin. Sphingomyelin and unsaturated phosphatidylcholine showed the highest susceptibility to toxin lypolitic action, with a two stage response to the toxin (an initial, rapid hydrolysis stage followed by the insertion and/or reorganisation of material in the monolayer). Fluorescence confocal microscopy on unsaturated phosphatidylcholine vesicles shows that the toxin initially aggregates at discrete sites followed by the formation of localised "droplets" accumulating the hydrolysis products. This process is accompanied by local increases in the membrane dipole potential by about 50 (±42) mV. In contrast, red blood cells incubated with the toxin suffered a decrease of the membrane dipole potential by 50 (±40) mV in areas of high toxin activity (equivalent to a change in electric field strength of 10(7) V m(-1)) which is sufficient to affect the functioning of the cell membrane. Changes in erythrocyte morphology caused by the toxin are presented, and the early stages of interaction between toxin and membrane are characterised using thermal shape fluctuation analysis of red cells which revealed two distinct regimes of membrane-toxin interaction.
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Affiliation(s)
- S A Jewell
- School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK.
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28
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Efimova SS, Malev VV, Ostroumova OS. Effects of Dipole Potential Modifiers on Heterogenic Lipid Bilayers. J Membr Biol 2015; 249:97-106. [PMID: 26454655 DOI: 10.1007/s00232-015-9852-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/29/2015] [Indexed: 01/29/2023]
Abstract
In this work, we examine the ability of dipole modifiers, flavonoids, and RH dyes to affect the dipole potential (φ d) and phase separation in membranes composed of ternary mixtures of POPC with different sphingolipids and sterols. Changes in the steady-state conductance induced by cation-ionophore complexes have been measured to evaluate the changes in dipole potential of planar lipid bilayers. Confocal fluorescence microscopy has been employed to investigate lipid segregation in giant unilamellar vesicles. The effects of flavonoids on φ d depend on lipid composition and dipole modifier type. The effectiveness of RH dyes to increase φ d depends on sphingolipid type but is not influenced by sterol content. Tested modifiers lead to partial or complete disruption of gel domains in bilayers composed of POPC, sphingomyelin, and cholesterol. Substitution of cholesterol to ergosterol or 7-dehydrocholesterol leads to a loss of fluidizing effects of modifiers except phloretin. This may be due to various compositions of gel domains. The lack of influence of modifiers on phase scenario in vesicles composed of ternary mixtures of POPC, cholesterol, and phytosphingosine or sphinganine is related to an absence of gel-like phase. It was concluded that the membrane lateral heterogeneity affects the dipole-modifying abilities of the agents that influence the magnitude of φ d by intercalation into the bilayer and orientation of its own large dipole moments (phloretin and RH dyes). The efficacy of modifiers that do not penetrate deeply and affect φ d through water adsorption (phlorizin, quercetin, and myricetin) is not influenced by lateral heterogeneity of membrane.
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Affiliation(s)
- Svetlana S Efimova
- Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky ave. 4, St. Petersburg, Russia, 194064.
| | - Valery V Malev
- Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky ave. 4, St. Petersburg, Russia, 194064.,St. Petersburg State University, Petergof, Russia, 198504
| | - Olga S Ostroumova
- Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky ave. 4, St. Petersburg, Russia, 194064
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29
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Watanabe C, Puff N, Staneva G, Angelova MI, Seigneuret M. Tuning of membrane electrostatic properties by single chain sphingolipids sphingosine and sphingosine-1-phosphate: The effect on bilayer dipole potential. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2015.06.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Richens JL, Lane JS, Bramble JP, O'Shea P. The electrical interplay between proteins and lipids in membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1828-36. [DOI: 10.1016/j.bbamem.2015.03.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 03/16/2015] [Accepted: 03/18/2015] [Indexed: 11/17/2022]
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Garcia A, Eljack ND, Sani MA, Separovic F, Rasmussen HH, Kopec W, Khandelia H, Cornelius F, Clarke RJ. Membrane accessibility of glutathione. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2430-6. [PMID: 26232559 DOI: 10.1016/j.bbamem.2015.07.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 07/23/2015] [Accepted: 07/28/2015] [Indexed: 10/23/2022]
Abstract
Regulation of the ion pumping activity of the Na+,K+-ATPase is crucial to the survival of animal cells. Recent evidence has suggested that the activity of the enzyme could be controlled by glutathionylation of cysteine residue 45 of the β-subunit. Crystal structures so far available indicate that this cysteine is in a transmembrane domain of the protein. Here we have analysed via fluorescence and NMR spectroscopy as well as molecular dynamics simulations whether glutathione is able to penetrate into the interior of a lipid membrane. No evidence for any penetration of glutathione into the membrane was found. Therefore, the most likely mechanism whereby the cysteine residue could become glutathionylated is via a loosening of the α-β subunit association, creating a hydrophilic passageway between them to allow access of glutathione to the cysteine residue. By such a mechanism, glutathionylation of the protein would be expected to anchor the modified cysteine residue in a hydrophilic environment, inhibiting further motion of the β-subunit during the enzyme's catalytic cycle and suppressing enzymatic activity, as has been experimentally observed. The results obtained, therefore, suggest a possible structural mechanism of how the Na+,K+-ATPase could be regulated by glutathione.
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Affiliation(s)
- Alvaro Garcia
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Nasma D Eljack
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Helge H Rasmussen
- Department of Cardiology, Royal North Shore Hospital, Sydney, New South Wales 2065, Australia; Kolling Institute, University of Sydney, Sydney, New South Wales 2065, Australia
| | - Wojciech Kopec
- Center for BioMembrane Physics, University of Southern Denmark, Odense M5230, Denmark
| | - Himanshu Khandelia
- Center for BioMembrane Physics, University of Southern Denmark, Odense M5230, Denmark
| | - Flemming Cornelius
- Department of Biomedicine, University of Aarhus, DK-8000 Aarhus C, Denmark
| | - Ronald J Clarke
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia.
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Davis S, Davis BM, Richens JL, Vere KA, Petrov PG, Winlove CP, O'Shea P. α-Tocopherols modify the membrane dipole potential leading to modulation of ligand binding by P-glycoprotein. J Lipid Res 2015; 56:1543-50. [PMID: 26026069 DOI: 10.1194/jlr.m059519] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Indexed: 11/20/2022] Open
Abstract
α-Tocopherol (vitamin E) has attracted considerable attention as a potential protective or palliative agent. In vitro, its free radical-scavenging antioxidant action has been widely demonstrated. In vivo, however, vitamin E treatment exhibits negligible benefits against oxidative stress. α-Tocopherol influences lipid ordering within biological membranes and its derivatives have been suggested to inhibit the multi-drug efflux pump, P-glycoprotein (P-gp). This study employs the fluorescent membrane probe, 1-(3-sulfonatopropyl)-4-[β[2-(di-n-octylamino)-6-naphthyl]vinyl] pyridinium betaine, to investigate whether these effects are connected via influences on the membrane dipole potential (MDP), an intrinsic property of biological membranes previously demonstrated to modulate P-gp activity. α-Tocopherol and its non-free radical-scavenging succinate analog induced similar decreases in the MDP of phosphatidylcholine vesicles. α-Tocopherol succinate also reduced the MDP of T-lymphocytes, subsequently decreasing the binding affinity of saquinavir for P-gp. Additionally, α-tocopherol succinate demonstrated a preference for cholesterol-treated (membrane microdomain enriched) cells over membrane cholesterol-depleted cells. Microdomain disruption via cholesterol depletion decreased saquinavir's affinity for P-gp, potentially implicating these structures in the influence of α-tocopherol succinate on P-gp. This study provides evidence of a microdomain dipole potential-dependent mechanism by which α-tocopherol analogs influence P-gp activity. These findings have implications for the use of α-tocopherol derivatives for drug delivery across biological barriers.
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Affiliation(s)
- Sterenn Davis
- Biomedical Physics Group, School of Physics, University of Exeter, Exeter, United Kingdom
| | - Benjamin M Davis
- Cell Biophysics Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Joanna L Richens
- Cell Biophysics Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Kelly-Ann Vere
- Cell Biophysics Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Peter G Petrov
- Biomedical Physics Group, School of Physics, University of Exeter, Exeter, United Kingdom
| | - C Peter Winlove
- Biomedical Physics Group, School of Physics, University of Exeter, Exeter, United Kingdom
| | - Paul O'Shea
- Cell Biophysics Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
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Mares LJ, Garcia A, Rasmussen HH, Cornelius F, Mahmmoud YA, Berlin JR, Lev B, Allen TW, Clarke RJ. Identification of electric-field-dependent steps in the Na(+),K(+)-pump cycle. Biophys J 2015; 107:1352-63. [PMID: 25229143 DOI: 10.1016/j.bpj.2014.05.054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 04/30/2014] [Accepted: 05/16/2014] [Indexed: 01/25/2023] Open
Abstract
The charge-transporting activity of the Na(+),K(+)-ATPase depends on its surrounding electric field. To isolate which steps of the enzyme's reaction cycle involve charge movement, we have investigated the response of the voltage-sensitive fluorescent probe RH421 to interaction of the protein with BTEA (benzyltriethylammonium), which binds from the extracellular medium to the Na(+),K(+)-ATPase's transport sites in competition with Na(+) and K(+), but is not occluded within the protein. We find that only the occludable ions Na(+), K(+), Rb(+), and Cs(+) cause a drop in RH421 fluorescence. We conclude that RH421 detects intramembrane electric field strength changes arising from charge transport associated with conformational changes occluding the transported ions within the protein, not the electric fields of the bound ions themselves. This appears at first to conflict with electrophysiological studies suggesting extracellular Na(+) or K(+) binding in a high field access channel is a major electrogenic reaction of the Na(+),K(+)-ATPase. All results can be explained consistently if ion occlusion involves local deformations in the lipid membrane surrounding the protein occurring simultaneously with conformational changes necessary for ion occlusion. The most likely origin of the RH421 fluorescence response is a change in membrane dipole potential caused by membrane deformation.
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Affiliation(s)
- Laura J Mares
- School of Chemistry, University of Sydney, Sydney, Australia
| | - Alvaro Garcia
- Department of Cardiology, Royal North Shore Hospital, Sydney, Australia; Kolling Institute, University of Sydney, Sydney, Australia
| | - Helge H Rasmussen
- Department of Cardiology, Royal North Shore Hospital, Sydney, Australia; Kolling Institute, University of Sydney, Sydney, Australia
| | | | | | - Joshua R Berlin
- Department of Pharmacology and Physiology, Rutgers University, Newark, New Jersey
| | - Bogdan Lev
- School of Applied Science and Health Innovations Research Institute, REMIT University, Melbourne, Australia
| | - Toby W Allen
- School of Applied Science and Health Innovations Research Institute, REMIT University, Melbourne, Australia
| | - Ronald J Clarke
- School of Chemistry, University of Sydney, Sydney, Australia.
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Zarzycki P. Interfacial water screens the protein-induced transmembrane voltage. J Phys Chem B 2015; 119:1474-82. [PMID: 25563965 DOI: 10.1021/jp509329u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transmembrane proteins are crucial in cellular traffic, signal transduction, and energy storage in a form of transmembrane voltage. These proteins are stabilized by hydrophobic and hydrophilic interactions, in which cytoplasmic and exoplasmic water plays a special role. Water structural ordering generates the dipole potential that typically overcompensates for an intrinsic membrane-protein potential gradient, and thus it modifies and sustains an overall cellular electrostatics. Although the transmembrane voltage has been extensively studied, the dipole potential has attracted very little attention. Here, by using molecular dynamics, we examined water electrostatic response to the transmembrane charge, field, and potential asymmetry introduced by the presence of four integral membrane proteins: typical of inner (α-helix) and outer membrane (β-barrel). In all cases, the protein presence introduces electrostatic directionality in the transmembrane dipole field and voltage. In particular, water generates a deep potential sink if strongly polar residues are densely packed on one side of bilayer, as frequently occurs in a selectivity filter of the K(+) channel. We also found that protein secondary structure is less important than the polar residue distribution along the protein channel. Our findings are relevant for understanding the driving force behind biomembrane conductivity: the ability of biological water to electrostatically screen the transmembrane voltage.
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Affiliation(s)
- Piotr Zarzycki
- Institute of Physical Chemistry, Polish Academy of Sciences , Warsaw, Poland
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Bohinc K, Giner-Casares JJ, May S. Analytic Model for the Dipole Potential of a Lipid Layer. J Phys Chem B 2014; 118:7568-7576. [PMID: 24912019 DOI: 10.1021/jp5050173] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The larger permeability of anions than cations through a lipid bilayer can be rationalized by the positive sign of the bilayer's dipole potential. That is, upon crossing the lipid headgroups toward the hydrocarbon chain region, the electrostatic potential increases by several hundred millivolts. We derive an analytic expression for the dipole potential of a single lipid layer using an electrostatic model that is based on an extended version of the linearized Poisson-Boltzmann theory. The model highlights the ability of the lipid headgroups to render the dipole potential positive by inducing an orientational ordering of the solvent molecules. The positive contribution of the solvent overcompensates the negative dipole potential due to the bare lipids. Our theoretical prediction compares accurately with measurements of the dipole potential that we have conducted for mixed anionic-zwitterionic lipid monolayers at the air-water interface.
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Affiliation(s)
- Klemen Bohinc
- Faculty of Health Sciences, University of Ljubljana , Zdravstvena 5, SI-1000 Ljubljana, Slovenia
| | - Juan J Giner-Casares
- BioNanoPlasmonics Lab, CIC biomaGUNE , 20009 Donostia - San Sebastian, Spain.,Department of Physical Chemistry and Applied Thermodynamics, University of Cordoba , Campus de Rabanales, Edificio Marie Curie, Cordoba E-14014, Spain
| | - Sylvio May
- Department of Physics, North Dakota State University , Fargo, North Dakota 58108-6050, United States
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Abstract
Any bilayer lipid membrane can support a membrane voltage. The combination of optical perturbation and optical readout of membrane voltage opens the door to studies of electrophysiology in a huge variety of systems previously inaccessible to electrode-based measurements. Yet, the application of optogenetic electrophysiology requires careful reconsideration of the fundamentals of bioelectricity. Rules of thumb appropriate for neuroscience and cardiology may not apply in systems with dramatically different sizes, lipid compositions, charge carriers, or protein machinery. Optogenetic tools are not electrodes; thus, optical and electrode-based measurements have different quirks. Here we review the fundamental aspects of bioelectricity with the aim of laying a conceptual framework for all-optical electrophysiology.
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Affiliation(s)
- Adam E Cohen
- Department of Chemistry and Chemical Biology and
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Rokitskaya TI, Kotova EA, Agapov II, Moisenovich MM, Antonenko YN. Unsaturated lipids protect the integral membrane peptide gramicidin A from singlet oxygen. FEBS Lett 2014; 588:1590-5. [PMID: 24613917 DOI: 10.1016/j.febslet.2014.02.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 02/10/2014] [Accepted: 02/17/2014] [Indexed: 10/25/2022]
Abstract
In contrast to expectations that unsaturated fatty acids contribute to oxidative stress by providing a source of lipid peroxides, we demonstrated the protective effect of double bonds in lipids on oxidative damage to membrane proteins. Photodynamic inactivation of gramicidin channels was decreased in unsaturated lipid compared to saturated lipid bilayers. By estimating photosensitizer (boronated chlorine e6 amide) binding to the membrane with the current relaxation technique, the decrease in gramicidin photoinactivation was attributed to singlet oxygen scavenging by double bonds in lipids rather than to the reduction in photosensitizer binding. Gramicidin protection by unsaturated lipids was also observed upon induction of oxidative stress with tert-butyl hydroperoxide.
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Affiliation(s)
- Tatyana I Rokitskaya
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation.
| | - Elena A Kotova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Igor I Agapov
- Biological Department, Lomonosov Moscow State University, Moscow, Russian Federation; Academician V.I.Shumakov Federal Research Center of Transplantology and Artificial Organs, Moscow, Russian Federation
| | - Mikhail M Moisenovich
- Biological Department, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Yuri N Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
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The alteration of lipid bilayer dynamics by phloretin and 6-ketocholestanol. Chem Phys Lipids 2013; 178:38-44. [PMID: 24316311 DOI: 10.1016/j.chemphyslip.2013.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 11/13/2013] [Accepted: 11/14/2013] [Indexed: 02/06/2023]
Abstract
Lipid bilayer properties are quantified with a variety of arbitrary selected parameters such as molecular packing and dynamics, electrostatic potentials or permeability. In the paper we determined the effect of phloretin and 6-ketocholestanol (dipole potential modifying agents) on the membrane hydration and efficiency of the trans-membrane water flow. The dynamics of water molecules within the lipid bilayer interface was evaluated using solvent relaxation method, whereas the osmotically induced trans-membrane water flux was estimated with the stopped-flow method using the liposome shrinkage kinetics. The presence of phloretin or 6-ketocholestanol resulted in a change of both, the interfacial hydration level and osmotically driven water fluxes. Specifically, the presence of 6-ketocholestanol reduced the amount and mobility of water in the membrane interface. It also slows the osmotically induced water flow. The interfacial hydration change caused by phloretin was much smaller and the effect on osmotically induced water flow was opposite to that of 6-ketocholestanol.
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Liu L, Xie H, Bostic HE, Jin L, Best MD, Zhang XP, Zhan W. Effects of oriented surface dipole on photoconversion efficiency in an alkane/lipid-hybrid-bilayer-based photovoltaic model system. Chemphyschem 2013; 14:2777-85. [PMID: 23794419 DOI: 10.1002/cphc.201300293] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Indexed: 11/08/2022]
Abstract
When a phospholipid monolayer containing a zinc-coordinated porphyrin species formed atop a self-assembled monolayer of heptadecafluoro-1-decanethiol (CF3(CF2)7(CH2)2SH) is subjected to photoelectrochemical current generation, a significant modulation effect is observed. Compared with devices that contain similar photoactive lipid monolayers but formed on 1-dodecanethiol SAMs, these fluorinated hybrid bilayers produce a >60% increase in cathodic currents and a similar decrease in anodic currents. Photovoltages recorded from these hybrid bilayers are found to vary in the same fashion. The modulation of photovoltaic responses in these hybrid-bilayer-based devices is explained by the opposite surface dipoles associated with the thiols employed in this study, which in one case (fluorothiol) increase and in another (alkanethiol) decrease the work function of the underlying gold substrates. A similar trend of photovoltage/photocurrent modulation is also observed if fullerene is used as the photoagent in these devices. Our results reveal the intricacy of orientated surface dipole in influencing the photovoltaic processes, and its subtle interplay with other factors related to the photoagents, such as their location and orientation within the organic matrix.
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Affiliation(s)
- Lixia Liu
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA
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Nankar SA, Pande AH. Physicochemical properties of bacterial pro-inflammatory lipids influence their interaction with apolipoprotein-derived peptides. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:853-62. [DOI: 10.1016/j.bbalip.2013.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 12/21/2012] [Accepted: 01/07/2013] [Indexed: 11/26/2022]
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Jewell SA, Petrov PG, Winlove CP. The effect of oxidative stress on the membrane dipole potential of human red blood cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1250-8. [PMID: 23313455 DOI: 10.1016/j.bbamem.2012.12.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 12/21/2012] [Accepted: 12/31/2012] [Indexed: 02/09/2023]
Abstract
The membrane dipole potential (ψ(d)) is an important biophysical determinant of membrane function and a sensitive indicator of lipid organisation. In this study we have used the environmentally sensitive probe di-8-anepps to explore the effects of oxidative stress on the membrane dipole potential of human erythrocytes. Cells suspended in 0.15mM phosphate buffered saline containing 0.1mg/ml albumin maintained a mean value for ψ(d) of 270 (±20) mV over the course of 1hour. In the presence of 0.4mM cumene hydroperoxide there was an increase in ψ(d) of 14 (±7)%, accompanied by a decrease in cell diameter of ~14 (±2)%. Exposure of the cells to 0.4mM hydrogen peroxide caused ψ(d) to decrease by 13 (±8)% at the centre of the cell and 8 (±5)% at the edge whilst the diameter remained constant. In both cases the changes were equivalent to a change in transmembrane electric field of a magnitude of ~10MVm(-1), sufficient to influence membrane function. Raman microspectrometry supported the conclusion that cumene exerts its effect primarily on membrane lipids whilst hydrogen peroxide causes the formation of spectrin-haemoglobin complexes which stiffen the membrane.
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Affiliation(s)
- S A Jewell
- School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK.
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Efimova SS, Ostroumova OS. Effect of dipole modifiers on the magnitude of the dipole potential of sterol-containing bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:9908-14. [PMID: 22702338 DOI: 10.1021/la301653s] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The effects of various subclasses of flavonoids, Rose Bengal, and different styrylpyridinium dyes on the magnitude of the dipole potential of membranes composed of pure phospholipids and sterol-containing bilayers were investigated. Changes in the steady-state membrane conductance induced by cation-ionophore complexes were measured to examine the changes in the dipole potential of lipid bilayers. The characteristic parameters of the Langmuir adsorption isotherm for different flavonoids and Rose Bengal and the slope of the linear dependence of the dipole potential change on the aqueous concentrations of RH dyes were estimated. Chalcones (phloretin and phloridzin) and flavonols (quercetin and myricetin) strictly decrease the dipole potential of phospholipid- and sterol-containing membranes; the unsaturation of the C-ring and the hydrophobicity of the molecule contribute to the ability of the flavonoid to reduce the bilayer dipole potential. Rose Bengal decreases the magnitude of the bilayer dipole potential to a similar extent, but its affinity for membrane lipids is higher; the effects of RH dyes, chalcones, and phloroglucinol are determined by sterol concentration and type.
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Affiliation(s)
- Svetlana S Efimova
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
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Reddy AS, Warshaviak DT, Chachisvilis M. Effect of membrane tension on the physical properties of DOPC lipid bilayer membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2271-81. [PMID: 22588133 DOI: 10.1016/j.bbamem.2012.05.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 05/03/2012] [Accepted: 05/07/2012] [Indexed: 01/15/2023]
Abstract
Molecular dynamics simulations of a dioleoylphosphocholine (DOPC) lipid bilayer were performed to explore its mechanosensitivity. Variations in the bilayer properties, such as area per lipid, volume, thickness, hydration depth (HD), hydration thickness (HT), lateral diffusion coefficient, and changes in lipid structural order were computed in the membrane tension range 0 to 15dyn/cm. We determined that an increase in membrane tension results in a decrease in the bilayer thickness and HD of ~5% and ~5.7% respectively, whereas area per lipid, volume, and HT/HD increased by 6.8%, 2.4%, and 5% respectively. The changes in lipid conformation and orientation were characterized using orientational (S(2)) and deuterium (S(CD)) order parameters. Upon increase of membrane tension both order parameters indicated an increase in lipid disorder by 10-20%, mostly in the tail end region of the hydrophobic chains. The effect of membrane tension on lipid lateral diffusion in the DOPC bilayer was analyzed on three different time scales corresponding to inertial motion, anomalous diffusion and normal diffusion. The results showed that lateral diffusion of lipid molecules is anomalous in nature due to the non-exponential distribution of waiting times. The anomalous and normal diffusion coefficients increased by 20% and 52% when the membrane tension changed from 0 to 15dyn/cm, respectively. In conclusion, our studies showed that membrane tension causes relatively significant changes in the area per lipid, volume, polarity, membrane thickness, and fluidity of the membrane suggesting multiple mechanisms by which mechanical perturbation of the membrane could trigger mechanosensitive response in cells.
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Lichtenberger LM, Zhou Y, Jayaraman V, Doyen JR, O'Neil RG, Dial EJ, Volk DE, Gorenstein DG, Boggara MB, Krishnamoorti R. Insight into NSAID-induced membrane alterations, pathogenesis and therapeutics: characterization of interaction of NSAIDs with phosphatidylcholine. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:994-1002. [PMID: 22521764 DOI: 10.1016/j.bbalip.2012.04.002] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 03/09/2012] [Accepted: 04/02/2012] [Indexed: 12/21/2022]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most widely consumed pharmaceuticals, yet both the mechanisms involved in their therapeutic actions and side-effects, notably gastrointestinal (GI) ulceration/bleeding, have not been clearly defined. In this study, we have used a number of biochemical, structural, computational and biological systems including; Fourier Transform InfraRed (FTIR). Nuclear Magnetic Resonance (NMR) and Surface Plasmon Resonance (SPR) spectroscopy, and cell culture using a specific fluorescent membrane probe, to demonstrate that NSAIDs have a strong affinity to form ionic and hydrophobic associations with zwitterionic phospholipids, and specifically phosphatidylcholine (PC), that are reversible and non-covalent in nature. We propose that the pH-dependent partition of these potent anti-inflammatory drugs into the phospholipid bilayer, and possibly extracellular mono/multilayers present on the luminal interface of the mucus gel layer, may result in profound changes in the hydrophobicity, fluidity, permeability, biomechanical properties and stability of these membranes and barriers. These changes may not only provide an explanation of how NSAIDs induce surface injury to the GI mucosa as a component in the pathogenic mechanism leading to peptic ulceration and bleeding, but potentially an explanation for a number of (COX-independent) biological actions of this family of pharmaceuticals. This insight also has proven useful in the design and development of a novel class of PC-associated NSAIDs that have reduced GI toxicity while maintaining their essential therapeutic efficacy to inhibit pain and inflammation.
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Affiliation(s)
- Lenard M Lichtenberger
- Department of Integrative Biology & Pharmacology, The Institute of Molecular Medicine, The University of Texas Health Science Center at Houston.
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Haldar S, Kanaparthi RK, Samanta A, Chattopadhyay A. Differential effect of cholesterol and its biosynthetic precursors on membrane dipole potential. Biophys J 2012; 102:1561-9. [PMID: 22500756 DOI: 10.1016/j.bpj.2012.03.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/17/2012] [Accepted: 03/02/2012] [Indexed: 01/16/2023] Open
Abstract
Dipole potential is the potential difference within the membrane bilayer, which originates due to the nonrandom arrangement of lipid dipoles and water molecules at the membrane interface. Cholesterol, a representative sterol in higher eukaryotic membranes, is known to increase membrane dipole potential. In this work, we explored the effects of immediate (7-DHC and desmosterol) and evolutionary (ergosterol) precursors of cholesterol on membrane dipole potential, monitored by the dual wavelength ratiometric approach utilizing the probe di-8-ANEPPS. Our results show that the effect of these precursors on membrane dipole potential is very different from that observed with cholesterol, although the structural differences among them are subtle. These results assume relevance, since accumulation of cholesterol precursors due to defective cholesterol biosynthesis has been reported to result in several inherited metabolic disorders such as the Smith-Lemli-Opitz syndrome. Interestingly, cholesterol (and its precursors) has a negligible effect on dipole potential in polyunsaturated membranes. We interpret these results in terms of noncanonical orientation of cholesterol in these membranes. Our results constitute the first report on the effect of biosynthetic and evolutionary precursors of cholesterol on dipole potential, and imply that a subtle change in sterol structure can significantly alter the dipolar field at the membrane interface.
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Affiliation(s)
- Sourav Haldar
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
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Abstract
There are three kinds of membrane potentials: the surface potentials, resulting from the accumulation of charges at the membrane surfaces; the transmembrane potential, determined by imbalance of charge in the aqueous solutions; and the dipole potential, a membrane-internal potential from the dipolar components of the phospholipids and interface water. The absolute value of the dipole potential has been very difficult to measure, although its value has been estimated to be in the range of 200-1,000 mV from ion translocation rates (determined by the planar lipid bilayer method), the surface potential of lipid monolayers (determined by the lipid monolayer method), molecular-dynamics calculations, and electron scattering using cryoelectron microscopy (cryo-EM). Spectroscopy methods have also been used to monitor the dipole potential changes on the basis of the observed fluorescence changes of voltage-sensitive probes. The dipole potential accounts for the much larger permeability of a bare phospholipid membrane to anions than cations and affects the conformation and function of membrane proteins.
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Affiliation(s)
- Liguo Wang
- Department of Biological Structure, University of Washington, Seattle, Washington 98195, USA.
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Berkovich AK, Lukashev EP, Melik-Nubarov NS. Dipole potential as a driving force for the membrane insertion of polyacrylic acid in slightly acidic milieu. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:375-83. [DOI: 10.1016/j.bbamem.2011.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 05/08/2011] [Accepted: 06/06/2011] [Indexed: 02/02/2023]
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48
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Dewald AH, Hodges JC, Columbus L. Physical determinants of β-barrel membrane protein folding in lipid vesicles. Biophys J 2011; 100:2131-40. [PMID: 21539780 DOI: 10.1016/j.bpj.2011.03.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/25/2011] [Accepted: 03/14/2011] [Indexed: 10/18/2022] Open
Abstract
The spontaneous folding of two Neisseria outer membrane proteins, opacity-associated (Opa)(60) and Opa(50) into lipid vesicles was investigated by systematically varying bulk and membrane properties. Centrifugal fractionation coupled with sodium dodecyl sulfate polyacrylamide gel electrophoresis mobility assays enabled the discrimination of aggregate, unfolded membrane-associated, and folded membrane-inserted protein states as well as the influence of pH, ionic strength, membrane surface potential, lipid saturation, and urea on each. Protein aggregation was reduced with increasing lipid chain length, basic pH, low salt, the incorporation of negatively charged guest lipids, or by the addition of urea to the folding reaction. Insertion from the membrane-associated form was improved in shorter chain lipids, with more basic pH and low ionic strength; it is hindered by unsaturated or ether-linked lipids. The isolation of the physical determinants of insertion suggests that the membrane surface and dipole potentials are driving forces for outer membrane protein insertion and folding into lipid bilayers.
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Affiliation(s)
- Alison H Dewald
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
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Robinson D, Besley NA, O’Shea P, Hirst JD. Di-8-ANEPPS Emission Spectra in Phospholipid/Cholesterol Membranes: A Theoretical Study. J Phys Chem B 2011; 115:4160-7. [DOI: 10.1021/jp1111372] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David Robinson
- School of Chemistry and ‡School of Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Nicholas A. Besley
- School of Chemistry and ‡School of Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Paul O’Shea
- School of Chemistry and ‡School of Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Jonathan D. Hirst
- School of Chemistry and ‡School of Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
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50
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Becucci L, Lottini E, Guidelli R. Influence of gel-phase microdomains and lipid rafts in lipid monolayers on the electron transfer of a lipophilic redox probe: dioctadecylviologen. Phys Chem Chem Phys 2011; 13:3917-24. [DOI: 10.1039/c0cp01928c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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