1
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Lauritsen L, Szomek M, Hornum M, Reinholdt P, Kongsted J, Nielsen P, Brewer JR, Wüstner D. Ratiometric fluorescence nanoscopy and lifetime imaging of novel Nile Red analogs for analysis of membrane packing in living cells. Sci Rep 2024; 14:13748. [PMID: 38877068 PMCID: PMC11178856 DOI: 10.1038/s41598-024-64180-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 06/05/2024] [Indexed: 06/16/2024] Open
Abstract
Subcellular membranes have complex lipid and protein compositions, which give rise to organelle-specific membrane packing, fluidity, and permeability. Due to its exquisite solvent sensitivity, the lipophilic fluorescence dye Nile Red has been used extensively to study membrane packing and polarity. Further improvement of Nile Red can be achieved by introducing electron-donating or withdrawing functional groups. Here, we compare the potential of derivatives of Nile Red with such functional substitutions for super-resolution fluorescence microscopy of lipid packing in model membranes and living cells. All studied Nile Red derivatives exhibit cholesterol-dependent fluorescence changes in model membranes, as shown by spectrally resolved stimulated emission depletion (STED) microscopy. STED imaging of Nile Red probes in cells reveals lower membrane packing in fibroblasts from healthy subjects compared to those from patients suffering from Niemann Pick type C1 (NPC1) disease, a lysosomal storage disorder with accumulation of cholesterol and sphingolipids in late endosomes and lysosomes. We also find small but consistent changes in the fluorescence lifetime of the Nile Red derivatives in NPC1 cells, suggesting altered hydrogen-bonding capacity in their membranes. All Nile Red derivatives are essentially non-fluorescent in water but increase their brightness in membranes, allowing for their use in MINFLUX single molecule tracking experiments. Our study uncovers the potential of Nile Red probes with functional substitutions for nanoscopic membrane imaging.
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Affiliation(s)
- Line Lauritsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Maria Szomek
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Mick Hornum
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Poul Nielsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Jonathan R Brewer
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
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2
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Hughes MP. The cellular zeta potential: cell electrophysiology beyond the membrane. Integr Biol (Camb) 2024; 16:zyae003. [PMID: 38291769 DOI: 10.1093/intbio/zyae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/16/2023] [Accepted: 01/06/2024] [Indexed: 02/01/2024]
Abstract
The standard model of the cell membrane potential Vm describes it as arising from diffusion currents across a membrane with a constant electric field, with zero electric field outside the cell membrane. However, the influence of Vm has been shown to extend into the extracellular space where it alters the cell's ζ-potential, the electrical potential measured a few nm from the cell surface which defines how the cell interacts with charged entities in its environment, including ions, molecules, and other cells. The paradigm arising from surface science is that the ζ-potential arises only from fixed membrane surface charge, and has consequently received little interest. However, if the ζ-potential can mechanistically and dynamically change by alteration of Vm, it allows the cell to dynamically alter cell-cell and cell-molecule interactions and may explain previously unexplained electrophysiological behaviours. Whilst the two potentials Vm and ζ are rarely reported together, they are occasionally described in different studies for the same cell type. By considering published data on these parameters across multiple cell types, as well as incidences of unexplained but seemingly functional Vm changes correlating with changes in cell behaviour, evidence is presented that this may play a functional role in the physiology of red blood cells, macrophages, platelets, sperm, ova, bacteria and cancer. Understanding how these properties will improve understanding of the role of electrical potentials and charges in the regulation of cell function and in the way in which cells interact with their environment. Insight The zeta (ζ) potential is the electrical potential a few nm beyond the surface of any suspensoid in water. Whilst typically assumed to arise only from fixed charges on the cell surface, recent and historical evidence shows a strong link to the cell's membrane potential Vm, which the cell can alter mechanistically through the use of ion channels. Whilst these two potentials have rarely been studied simultaneously, this review collates data across multiple studies reporting Vm, ζ-potential, electrical properties of changes in cell behaviour. Collectively, this points to Vm-mediated ζ-potential playing a significant role in the physiology and activity of blood cells, immune response, developmental biology and egg fertilization, and cancer among others.
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Affiliation(s)
- Michael Pycraft Hughes
- Department of Biomedical Engineering/Healthcare Engineering Innovation Centre (HEIC), Khalifa University, Abu Dhabi, UAE
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3
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Tamucci JD, Alder NN, May ER. Peptide Power: Mechanistic Insights into the Effect of Mitochondria-Targeted Tetrapeptides on Membrane Electrostatics from Molecular Simulations. Mol Pharm 2023; 20:6114-6129. [PMID: 37904323 PMCID: PMC10841697 DOI: 10.1021/acs.molpharmaceut.3c00480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Mitochondrial dysfunction is implicated in nine of the ten leading causes of death in the US, yet there are no FDA-approved therapeutics to treat it. Synthetic mitochondria-targeted peptides (MTPs), including the lead compound SS-31, offer promise, as they have been shown to restore healthy mitochondrial function and treat a variety of common diseases. At the cellular level, research has shown that MTPs accumulate strongly at the inner mitochondrial membrane (IMM), slow energy sinks (e.g., proton leaks), and improve ATP production. Modulation of electrostatic fields around the IMM has been implicated as a key aspect in the mechanism of action (MoA) of these peptides; however, molecular and mechanistic details have remained elusive. In this study, we employed all-atom molecular dynamics simulations (MD) to investigate the interactions of four MTPs with lipid bilayers and calculate their effect on structural and electrostatic properties. In agreement with previous experimental findings, we observed the modulation of the membrane surface and dipole potentials by MTPs. The simulations reveal that the MTPs achieve a reduction in the dipole potential by acting to disorder both lipid head groups and water layers proximal to the bilayer surface. We also find that MTPs decrease the bilayer thickness and increase the membrane's capacitance. These changes suggest that MTPs may enhance how much potential energy can be stored across the IMM at a given transmembrane potential difference. The MTPs also displace cations away from the bilayer surface, modulating the surface potential and offering an alternative mechanism for how these MTPs reduce mitochondrial energy sinks like proton leaks and mitigate Ca2+ accumulation stress. In conclusion, this study highlights the therapeutic potential of MTPs and underlines how interactions of MTPs with lipid bilayers serve as a fundamental component of their MoA.
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Affiliation(s)
- Jeffrey D Tamucci
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Nathan N Alder
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Eric R May
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, United States
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4
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Demchenko AP. Proton transfer reactions: from photochemistry to biochemistry and bioenergetics. BBA ADVANCES 2023. [DOI: 10.1016/j.bbadva.2023.100085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
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5
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Chromone-Containing Allylmorpholines Influence Ion Channels in Lipid Membranes via Dipole Potential and Packing Stress. Int J Mol Sci 2022; 23:ijms231911554. [PMID: 36232854 PMCID: PMC9570167 DOI: 10.3390/ijms231911554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 09/23/2022] [Accepted: 09/27/2022] [Indexed: 11/17/2022] Open
Abstract
Herein, we report that chromone-containing allylmorpholines can affect ion channels formed by pore-forming antibiotics in model lipid membranes, which correlates with their ability to influence membrane boundary potential and lipid-packing stress. At 100 µg/mL, allylmorpholines 1, 6, 7, and 8 decrease the boundary potential of the bilayers composed of palmitoyloleoylphosphocholine (POPC) by about 100 mV. At the same time, the compounds do not affect the zeta-potential of POPC liposomes, but reduce the membrane dipole potential by 80-120 mV. The allylmorpholine-induced drop in the dipole potential produce 10-30% enhancement in the conductance of gramicidin A channels. Chromone-containing allylmorpholines also affect the thermotropic behavior of dipalmytoylphosphocholine (DPPC), abolishing the pretransition, lowering melting cooperativity, and turning the main phase transition peak into a multicomponent profile. Compounds 4, 6, 7, and 8 are able to decrease DPPC's melting temperature by about 0.5-1.9 °C. Moreover, derivative 7 is shown to increase the temperature of transition of palmitoyloleoylphosphoethanolamine from lamellar to inverted hexagonal phase. The effects on lipid-phase transitions are attributed to the changes in the spontaneous curvature stress. Alterations in lipid packing induced by allylmorpholines are believed to potentiate the pore-forming ability of amphotericin B and gramicidin A by several times.
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6
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Yesylevskyy S, Khandelia H. EnCurv: Simple Technique of Maintaining Global Membrane Curvature in Molecular Dynamics Simulations. J Chem Theory Comput 2021; 17:1181-1193. [DOI: 10.1021/acs.jctc.0c00800] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Semen Yesylevskyy
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, 03028 Kyiv, Ukraine
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030 Besançon Cedex, France
| | - Himanshu Khandelia
- PHYLIFE: Physical Life Science, Department of Physics Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, Odense 5230 M, Denmark
- MEMPHYS: Center for Biomembrane Physics,
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7
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Bignucolo O, Bernèche S. The Voltage-Dependent Deactivation of the KvAP Channel Involves the Breakage of Its S4 Helix. Front Mol Biosci 2020; 7:162. [PMID: 32850956 PMCID: PMC7403406 DOI: 10.3389/fmolb.2020.00162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 06/24/2020] [Indexed: 11/13/2022] Open
Abstract
Voltage-gated potassium channels (Kv) allow ion permeation upon changes of the membrane electrostatic potential (Vm). Each subunit of these tetrameric channels is composed of six transmembrane helices, of which the anti-parallel helix bundle S1-S4 constitutes the voltage-sensor domain (VSD) and S5-S6 forms the pore domain. Here, using 82 molecular dynamics (MD) simulations involving 266 replicated VSDs, we report novel responses of the archaebacterial potassium channel KvAP to membrane polarization. We show that the S4 α-helix, which is straight in the experimental crystal structure solved under depolarized conditions (Vm ∼ 0), breaks into two segments when the cell membrane is hyperpolarized (Vm << 0), and reversibly forms a single straight helix following depolarization (Vm = 0). The outermost segment of S4 translates along the normal to the membrane, bringing new perspective to previously paradoxical accessibility experiments that were initially thought to imply the displacement of the whole VSD across the membrane. The novel model is applied through steered and unbiased MD simulations to the recently solved whole structure of KvAP. The simulations show that the resting state involves a re-orientation of the S5 α-helix by ∼ 5-6 degrees in respect to the normal of the bilayer, which could result in the constriction and closure of the selectivity filter. Our findings support the idea that the breakage of S4 under (hyper)polarization is a general feature of Kv channels with a non-swapped topology.
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Affiliation(s)
- Olivier Bignucolo
- Biozentrum, University of Basel, Basel, Switzerland.,SIB Swiss Institute of Bioinformatics, Basel/Lausanne, Switzerland
| | - Simon Bernèche
- Biozentrum, University of Basel, Basel, Switzerland.,SIB Swiss Institute of Bioinformatics, Basel/Lausanne, Switzerland
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8
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Benarroch JM, Asally M. The Microbiologist’s Guide to Membrane Potential Dynamics. Trends Microbiol 2020; 28:304-314. [DOI: 10.1016/j.tim.2019.12.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/25/2019] [Accepted: 12/09/2019] [Indexed: 10/25/2022]
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9
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Yesylevskyy S, Rivel T, Ramseyer C. Curvature increases permeability of the plasma membrane for ions, water and the anti-cancer drugs cisplatin and gemcitabine. Sci Rep 2019; 9:17214. [PMID: 31748538 PMCID: PMC6868207 DOI: 10.1038/s41598-019-53952-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 09/26/2019] [Indexed: 01/15/2023] Open
Abstract
In this work the permeability of a model asymmetric plasma membrane, for ions, water and the anti-cancer drugs cisplatin and gemcitabine is studied by means of all-atom molecular dynamics simulations. It is shown for the first time that permeability of the highly curved membrane increases from one to three orders of magnitude upon membrane bending depending on the compound and the sign of curvature. Our results suggest that the membrane curvature could be an important factor of drug translocation through the membrane.
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Affiliation(s)
- Semen Yesylevskyy
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France.
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, 03028, Kyiv, Ukraine.
| | - Timothée Rivel
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
| | - Christophe Ramseyer
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
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10
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Zakharova AA, Efimova SS, Schagina LV, Malev VV, Ostroumova OS. Blocking ion channels induced by antifungal lipopeptide syringomycin E with amide-linked local anesthetics. Sci Rep 2018; 8:11543. [PMID: 30069037 PMCID: PMC6070474 DOI: 10.1038/s41598-018-30077-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 07/24/2018] [Indexed: 11/22/2022] Open
Abstract
The effects of the amide-linked (lidocaine (LDC), mepivacaine (MPV), prilocaine (PLC)) and ester-bound local anesthetics (benzocaine (BZC), procaine (PRC), and tetracaine (TTC)) on the pore-forming activity of the antifungal lipopeptide syringomycin E (SRE) in lipid bilayers were studied. Independently on electrolyte concentration in the membrane bathing solution the observed changes in conductance of SRE channels agreed with the altered membrane dipole potential under the action of ester-bound local anesthetics. Effects of aminoamides in diluted and concentrated solutions were completely different. At 0.1 M KCl (pH 7.4) the effects of amide-linked anesthetics were in accordance with changes in the membrane surface potential, while at 2 M KCl aminoamides blocked ion passage through the SRE channels, leading to sharp reductions in pore conductance at negative voltages and 100-fold decreases in the channel lifetimes. The effects were not practically influenced by the membrane lipid composition. The interaction cooperativity implied the existence of specific binding sites for amide-bound anesthetics in SRE channels.
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Affiliation(s)
- Anastasiia A Zakharova
- Institute of Cytology of the Russian Academy of Sciences, 4 Tikhoretsky prospect, St. Petersburg, 194064, Russia
| | - Svetlana S Efimova
- Institute of Cytology of the Russian Academy of Sciences, 4 Tikhoretsky prospect, St. Petersburg, 194064, Russia
| | - Ludmila V Schagina
- Institute of Cytology of the Russian Academy of Sciences, 4 Tikhoretsky prospect, St. Petersburg, 194064, Russia
| | - Valery V Malev
- Institute of Cytology of the Russian Academy of Sciences, 4 Tikhoretsky prospect, St. Petersburg, 194064, Russia.,Saint Petersburg State University, Institute of Chemistry, 26 Universitetskii prospect, St. Petersburg, Petergof, 198504, Russia
| | - Olga S Ostroumova
- Institute of Cytology of the Russian Academy of Sciences, 4 Tikhoretsky prospect, St. Petersburg, 194064, Russia.
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11
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Yesylevskyy SO, Rivel T, Ramseyer C. The influence of curvature on the properties of the plasma membrane. Insights from atomistic molecular dynamics simulations. Sci Rep 2017; 7:16078. [PMID: 29167583 PMCID: PMC5700167 DOI: 10.1038/s41598-017-16450-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 11/13/2017] [Indexed: 11/24/2022] Open
Abstract
In this work we conduct a systematic analysis of the influence of curvature on various properties of a realistic model of mammalian plasma membrane with asymmetric lipid content of monolayers and a realistic concentration of cholesterol. In order to do this we developed new technique for simulating membranes with the global membrane curvature restricted to any desirable value while keeping free lateral diffusion of the lipids and without introducing artifacts or perturbing the membrane structure. We show that the thickness of the hydrophobic core of the concave monolayer decreases by approximately 1.3 Å in comparison to that of the flat membrane, while the thickness of the convex monolayer does not change. The order parameter of the lipid tails decreases significantly in the certain layers of the curved membrane. The area per lipid increases in the convex monolayer and decreases in the concave monolayer. The cholesterol inclination angle decreases when the curvature of a particular monolayer changes from concave to convex. The amount of cholesterol in the minor fraction located between the membrane leaflets is zero in the membrane with positive curvature and increases to 1.7% in the flat membrane and to 2.5% in the membrane with negative curvature.
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Affiliation(s)
- Semen O Yesylevskyy
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, Kyiv, 03680, Ukraine.
| | - Timothée Rivel
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
| | - Christophe Ramseyer
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
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12
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Przybyło M, Drabik D, Szostak K, Borowik T, Klösgen B, Dobrucki J, Sikorski AF, Langner M. Changes in lipid membrane mechanics induced by di- and tri-phenyltins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1301-1309. [PMID: 28461050 DOI: 10.1016/j.bbamem.2017.04.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 11/29/2022]
Abstract
Organotin compounds, being biologically active, affect a variety of cellular functions due to their ability to accumulate in and penetrate biological membranes. These compounds influence the distribution of electrostatic charges, alter organization, disrupt molecular dynamics and change mechanical properties of biological membranes. It was found that the membrane/water partition coefficient equals 4, a value significantly higher than octanol/water partition coefficient. In addition, the effect of di- and tri-phenyltin chlorides on the mechanics of model lipid membranes was measured for the first time. It has been determined that phenyltins affect the global model lipid bilayer properties by reducing the membrane expansion modulus, when measured using micromanipulation technique, and elevating the bending rigidity coefficient of the lipid bilayer, as determined with the flickering noise spectroscopy. In addition, the elevated water permeability shows that phenyltins also cause the local defects formation in the lipid bilayer, i.e. lipid pores. These data shows that phenyltins may interfere indirectly with variety cellular processes by altering non-specifically the entire cellular membrane system. Accordingly, when phenyltins are added to macrophages in culture, they inflict massive alterations of cell morphology and interfere with membrane-associated processes, as visualized using fluorescence labelling of selected subcellular compartments.
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Affiliation(s)
- Magda Przybyło
- Wrocław University of Science and Technology, Faculty of Fundamental Technical Problems, Department of Biomedical Engineering, 50-377 Wrocław, pl. Grunwaldzki 13, Poland; Lipid Systems sp. z o.o., 54-613 Wrocław, ul Krzemieniecka 48,C, Poland
| | - Dominik Drabik
- Wrocław University of Science and Technology, Faculty of Fundamental Technical Problems, Department of Biomedical Engineering, 50-377 Wrocław, pl. Grunwaldzki 13, Poland.
| | - Kamila Szostak
- Wrocław University of Science and Technology, Faculty of Fundamental Technical Problems, Department of Biomedical Engineering, 50-377 Wrocław, pl. Grunwaldzki 13, Poland
| | - Tomasz Borowik
- Wrocław University of Science and Technology, Faculty of Fundamental Technical Problems, Department of Biomedical Engineering, 50-377 Wrocław, pl. Grunwaldzki 13, Poland
| | - Beate Klösgen
- Department of Physics, Chemistry and Pharmacy, MEMPHYS Centre, Campusvej 55, 5230 Odense M, Denmark
| | - Jurek Dobrucki
- Department of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387 Krakow, Poland
| | - Aleksander F Sikorski
- Laboratory of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, ul. Joliot-Curie 14a, Wrocław, Poland
| | - Marek Langner
- Wrocław University of Science and Technology, Faculty of Fundamental Technical Problems, Department of Biomedical Engineering, 50-377 Wrocław, pl. Grunwaldzki 13, Poland; Lipid Systems sp. z o.o., 54-613 Wrocław, ul Krzemieniecka 48,C, Poland
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13
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Garcia A, Pratap PR, Lüpfert C, Cornelius F, Jacquemin D, Lev B, Allen TW, Clarke RJ. The voltage-sensitive dye RH421 detects a Na + ,K + -ATPase conformational change at the membrane surface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:813-823. [DOI: 10.1016/j.bbamem.2017.01.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/09/2017] [Accepted: 01/19/2017] [Indexed: 10/20/2022]
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14
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Cherniavskyi YK, Ramseyer C, Yesylevskyy SO. Interaction of C60 fullerenes with asymmetric and curved lipid membranes: a molecular dynamics study. Phys Chem Chem Phys 2015; 18:278-84. [PMID: 26608905 DOI: 10.1039/c5cp05838d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Interaction of fullerenes with asymmetric and curved DOPC/DOPS bicelles is studied by means of coarse-grained molecular dynamics simulations. The effects caused by asymmetric lipid composition of the membrane leaflets and the curvature of the membrane are analyzed. It is shown that the aggregates of fullerenes prefer to penetrate into the membrane in the regions of the moderately positive mean curvature. Upon penetration into the hydrophobic core of the membrane fullerenes avoid the regions of the extreme positive or the negative curvature. Fullerenes increase the ordering of lipid tails, which are in direct contact with them, but do not influence other lipids significantly. Our data suggest that the effects of the membrane curvature should be taken into account in the studies concerning permeability of the membranes to fullerenes and fullerene-based drug delivery systems.
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Affiliation(s)
- Yevhen K Cherniavskyi
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, Kiev-28, 03680, Ukraine.
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15
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Ray S, Kassan A, Busija AR, Rangamani P, Patel HH. The plasma membrane as a capacitor for energy and metabolism. Am J Physiol Cell Physiol 2015; 310:C181-92. [PMID: 26771520 DOI: 10.1152/ajpcell.00087.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
When considering which components of the cell are the most critical to function and physiology, we naturally focus on the nucleus, the mitochondria that regulate energy and apoptotic signaling, or other organelles such as the endoplasmic reticulum, Golgi, ribosomes, etc. Few people will suggest that the membrane is the most critical element of a cell in terms of function and physiology. Those that consider the membrane critical will point to its obvious barrier function regulated by the lipid bilayer and numerous ion channels that regulate homeostatic gradients. What becomes evident upon closer inspection is that not all membranes are created equal and that there are lipid-rich microdomains that serve as platforms of signaling and a means of communication with the intracellular environment. In this review, we explore the evolution of membranes, focus on lipid-rich microdomains, and advance the novel concept that membranes serve as "capacitors for energy and metabolism." Within this framework, the membrane then is the primary and critical regulator of stress and disease adaptation of the cell.
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Affiliation(s)
- Supriyo Ray
- Department of Veterans Affairs San Diego Healthcare System, San Diego, California; Department of Anesthesiology, University of California, San Diego, La Jolla, California; and
| | - Adam Kassan
- Department of Veterans Affairs San Diego Healthcare System, San Diego, California; Department of Anesthesiology, University of California, San Diego, La Jolla, California; and
| | - Anna R Busija
- Department of Veterans Affairs San Diego Healthcare System, San Diego, California; Department of Anesthesiology, University of California, San Diego, La Jolla, California; and
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California
| | - Hemal H Patel
- Department of Veterans Affairs San Diego Healthcare System, San Diego, California; Department of Anesthesiology, University of California, San Diego, La Jolla, California; and
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16
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The interactions of peripheral membrane proteins with biological membranes. Chem Phys Lipids 2015; 192:51-59. [DOI: 10.1016/j.chemphyslip.2015.07.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/14/2015] [Accepted: 07/25/2015] [Indexed: 11/22/2022]
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17
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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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18
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Nåbo LJ, List NH, Witzke S, Wüstner D, Khandelia H, Kongsted J. Design of new fluorescent cholesterol and ergosterol analogs: Insights from theory. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2188-99. [DOI: 10.1016/j.bbamem.2015.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/24/2015] [Accepted: 04/29/2015] [Indexed: 12/23/2022]
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19
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Cardenas AE, Shrestha R, Webb LJ, Elber R. Membrane permeation of a peptide: it is better to be positive. J Phys Chem B 2015; 119:6412-20. [PMID: 25941740 DOI: 10.1021/acs.jpcb.5b02122] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A joint experimental and computational study investigates the translocation of a tryptophan molecule through a phospholipid membrane. Time dependent spectroscopy of the tryptophan side chain determines the rate of permeation into 150 nm phospholipid vesicles. Atomically detailed simulations are conducted to calculate the free energy profiles and the permeation coefficient. Different charging conditions of the peptide (positive, negative, or zwitterion) are considered. Both experiment and simulation reproduce the qualitative trend and suggest that the fastest permeation is when the tryptophan is positively charged. The permeation mechanism, which is revealed by molecular dynamics simulations, is of a translocation assisted by a local defect. The influence of long-range electrostatic interactions, such as the membrane dipole potential on the permeation process, is not significant.
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Affiliation(s)
- Alfredo E Cardenas
- †Institute for Computational Engineering and Sciences and ‡Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Rebika Shrestha
- †Institute for Computational Engineering and Sciences and ‡Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Lauren J Webb
- †Institute for Computational Engineering and Sciences and ‡Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Ron Elber
- †Institute for Computational Engineering and Sciences and ‡Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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20
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Modifiers of membrane dipole potentials as tools for investigating ion channel formation and functioning. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 315:245-97. [PMID: 25708465 DOI: 10.1016/bs.ircmb.2014.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrostatic fields generated on and within biological membranes play a fundamental role in key processes in cell functions. The role of the membrane dipole potential is of particular interest because of its powerful impact on membrane permeability and lipid-protein interactions, including protein insertion, oligomerization, and function. The membrane dipole potential is defined by the orientation of electric dipoles of lipid headgroups, fatty acid carbonyl groups, and membrane-adsorbed water. As a result, the membrane interior is several hundred millivolts more positive than the external aqueous phase. This potential decrease depends on the lipid, and especially sterol, composition of the membrane. The adsorption of certain electroneutral molecules known as dipole modifiers may also lead to significant changes in the magnitude of the potential decrease. These agents are widely used to study the effects of the dipole potential on membrane transport. This review presents a critical analysis of a variety of data from studies dedicated to ion channel formation and functioning in membranes with different dipole potentials. The types of ion channels found in cellular membranes and pores formed by antimicrobial agents and toxins in artificial lipid membranes are summarized. The mechanisms underlying the influence of the membrane dipole potential on ion channel activity, including dipole-dipole and charge-dipole interactions in the pores and in membranes, are discussed. A hypothesis, in which lipid rafts in both model and cellular membranes also modulate ion channel activity by virtue of an increased or decreased dipole potential, is also considered.
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21
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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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22
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Antunes E, Cruz CF, Azoia NG, Cavaco-Paulo A. The effects of solvent composition on the affinity of a peptide towards hair keratin: experimental and molecular dynamics data. RSC Adv 2015. [DOI: 10.1039/c4ra13901a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Molecular dynamics simulations with a developed hair protofibril model demonstrated the ability to improve peptide uptake by hair shafts.
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Affiliation(s)
- Egipto Antunes
- CEB – Centre of Biological Engineering
- University of Minho
- 4710-057 Braga
- Portugal
| | - Célia F. Cruz
- CEB – Centre of Biological Engineering
- University of Minho
- 4710-057 Braga
- Portugal
| | - Nuno G. Azoia
- CEB – Centre of Biological Engineering
- University of Minho
- 4710-057 Braga
- Portugal
| | - Artur Cavaco-Paulo
- CEB – Centre of Biological Engineering
- University of Minho
- 4710-057 Braga
- Portugal
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Yesylevskyy SO, Demchenko AP. Cholesterol behavior in asymmetric lipid bilayers: insights from molecular dynamics simulations. Methods Mol Biol 2015; 1232:291-306. [PMID: 25331142 DOI: 10.1007/978-1-4939-1752-5_20] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Asymmetric lipid composition of the cell membranes plays an important role in the multitude of important biological functions. Much less is known, however, about the distribution and dynamics of cholesterol in asymmetric biological membranes. In this work we show how this issue could be addressed computationally by molecular dynamics simulations. The influence of the lipid head group charge, acyl chain saturation, spontaneous membrane curvature and the surface tension of the membrane on cholesterol distribution in asymmetric lipid bilayers is investigated. Four asymmetric bilayers containing DOPC, DOPS, DSPC, or DSPS lipids, were simulated on the time scale extended to tens of microseconds. We show that cholesterol strongly prefers anionic lipids to neutral and saturated lipid tails to unsaturated with distribution ratio ~0.4-0.6. Multiple flip-flop transitions of cholesterol were observed directly and their mean times range from 350 to 2,000 ns. It was shown that the distribution of cholesterol in the asymmetric bilayer depends not only on the type of lipids but also on the local membrane curvature and the surface tension. The geometric shape of spontaneously curved asymmetric bilayer changes dramatically in the presence of cholesterol. The membrane curvature becomes less homogeneous with large patches of flattened regions interleaved by rather sharp bends.
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Affiliation(s)
- Semen O Yesylevskyy
- Institute of Physics, National Academy of Sciences of Ukraine, Prospect Nauky, 46, Kiev, 03039, Ukraine,
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Polak A, Tarek M, Tomšič M, Valant J, Ulrih NP, Jamnik A, Kramar P, Miklavčič D. Electroporation of archaeal lipid membranes using MD simulations. Bioelectrochemistry 2014; 100:18-26. [DOI: 10.1016/j.bioelechem.2013.12.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 12/24/2013] [Accepted: 12/31/2013] [Indexed: 12/13/2022]
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26
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Yesylevskyy SO, Ramseyer C. Determination of mean and Gaussian curvatures of highly curved asymmetric lipid bilayers: the case study of the influence of cholesterol on the membrane shape. Phys Chem Chem Phys 2014; 16:17052-61. [DOI: 10.1039/c4cp01544d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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27
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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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28
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Yesylevskyy SO, Kraszewski S, Ramseyer C. Determination of the shape and curvature of nonplanar lipid bilayers that are bent in a single plane in molecular dynamics simulations. J Mol Model 2014; 20:2176. [DOI: 10.1007/s00894-014-2176-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 02/08/2014] [Indexed: 11/29/2022]
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29
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Amazon JJ, Feigenson GW. Lattice simulations of phase morphology on lipid bilayers: renormalization, membrane shape, and electrostatic dipole interactions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:022702. [PMID: 25353504 PMCID: PMC4391078 DOI: 10.1103/physreve.89.022702] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Indexed: 06/03/2023]
Abstract
When liquid phases coexist at equilibrium but are not driven to minimize domain interfacial contact energy, the resulting patterns of phase domains can have important implications for living cells. In this study we explore some of the interactions and conditions that produce the stable patterned phases that are observed in model lipid mixtures. By use of Monte Carlo simulations we find that background curvature is important for the formation of patterned (modulated) phases. The interactions that stabilize nanoscopic phase separation are still not well understood. We show that inclusion of an electrostatic dipole repulsion with decay lengths as short as two to four lipid diameters can break up domains at the nanometer scale and that the location of the miscibility critical point is sensitive to this interaction. The use of a coarse-grained simulation raises questions about comparing parameters in simulations performed at different length scales. Using renormalization group techniques we show how to reconcile this problem, treating line tension as a running coupling constant.
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Affiliation(s)
- Jonathan J Amazon
- Field of Biophysics, Cornell University, Ithaca, New York 14850, USA
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30
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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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31
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Elsheshiny AAA, Ashcroft AE, Harris SA. A comparison of the electromechanical properties of structurally diverse proteins by molecular dynamics simulation. J Biomol Struct Dyn 2013; 32:1734-41. [PMID: 24028659 DOI: 10.1080/07391102.2013.833864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Proteins are subjected to electric fields both within the cell and during routine biochemical analysis. We have used atomistic molecular dynamics simulations to study conformational changes within three structurally diverse proteins subjected to high electric fields. At electric fields in excess of .5 V/nm, major structural changes were observed in all three proteins due to charge redistribution within the biomolecule. However, the electromechanical resilience was found to be highly dependent on the protein secondary structure, with α-helices showing a particularly high susceptibility to deformation by the applied electric field.
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32
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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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Malhotra K, Sathappa M, Landin JS, Johnson AE, Alder NN. Structural changes in the mitochondrial Tim23 channel are coupled to the proton-motive force. Nat Struct Mol Biol 2013; 20:965-72. [DOI: 10.1038/nsmb.2613] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 05/14/2013] [Indexed: 01/11/2023]
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34
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Demchenko AP, Tang KC, Chou PT. Excited-state proton coupled charge transfer modulated by molecular structure and media polarization. Chem Soc Rev 2013; 42:1379-408. [PMID: 23169387 DOI: 10.1039/c2cs35195a] [Citation(s) in RCA: 447] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Charge and proton transfer reactions in the excited states of organic dyes can be coupled in many different ways. Despite the complementarity of charges, they can occur on different time scales and in different directions of the molecular framework. In certain cases, excited-state equilibrium can be established between the charge-transfer and proton-transfer species. The interplay of these reactions can be modulated and even reversed by variations in dye molecular structures and changes of the surrounding media. With knowledge of the mechanisms of these processes, desired rates and directions can be achieved, and thus the multiple emission spectral features can be harnessed. These features have found versatile applications in a number of cutting-edge technological areas, particularly in fluorescence sensing and imaging.
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Affiliation(s)
- Alexander P Demchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha street, Kiev 01030, Ukraine.
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Cholesterol induces uneven curvature of asymmetric lipid bilayers. ScientificWorldJournal 2013; 2013:965230. [PMID: 23766730 PMCID: PMC3671548 DOI: 10.1155/2013/965230] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 04/28/2013] [Indexed: 01/07/2023] Open
Abstract
A remarkable flexibility is observed in biological membranes, which allows them to form the structures of different curvatures. We addressed the question of intrinsic ability of phospholipid membranes to form highly curved structures and the role of cholesterol in this process. The distribution of cholesterol in the highly curved asymmetric DOPC/DOPS lipid bilayer was investigated by the coarse-grained molecular dynamics simulations in the membrane patches with large aspect ratio. It is shown that cholesterol induces uneven membrane curvature promoting the formation of extended flattened regions of the membrane interleaved by sharp bends. It is shown that the affinity of cholesterol to anionic DOPS or neutral DOPC lipids is curvature dependent. The cholesterol prefers DOPS to DOPC in either planar or highly curved parts of the membrane. In contrast, in the narrow interval of moderate membrane curvatures this preference is inverted. Our data suggest that there is a complex self-consistent interplay between the membrane curvature and cholesterol distribution in the asymmetric lipid bilayers. The suggested new function of cholesterol may have a biological relevance.
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36
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Demchenko AP. Nanoparticles and nanocomposites for fluorescence sensing and imaging. Methods Appl Fluoresc 2013; 1:022001. [DOI: 10.1088/2050-6120/1/2/022001] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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37
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Barucha-Kraszewska J, Kraszewski S, Ramseyer C. Will C-Laurdan dethrone Laurdan in fluorescent solvent relaxation techniques for lipid membrane studies? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:1174-82. [PMID: 23311388 DOI: 10.1021/la304235r] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Development of fluorescence methods involves the necessity of understanding the fluorescent probes behavior in their ground and excited states. In the case of biological membranes, the position of the dyes in the lipid bilayer and their response after excitation are necessary parameters to correctly analyze the experiments. In the present work, we focus on two fluorescent markers, Laurdan (6-lauroyl-2-(N,N-dimethylamino)naphthalene) and its derivative C-Laurdan (6-dodecanoyl-2-[N-methyl-N-(carboxymethyl)amino]naphthalene), recently proposed for lipid raft visualization [Kim, H. M.; et al. ChemBioChem 2007, 8, 553]. C-Laurdan, by the presence of an additional carboxyl group, has an advantage over Laurdan since it has a higher sensitivity to the membrane polarity at the lipid headgroup region and a higher water solubility. This theoretical study, based on quantum mechanical (QM) and molecular dynamics (MD) simulations in a fully hydrated lipid membrane model, compare the equilibrium and dynamic properties of both probes taking into account their fluorescence lifetimes. C-Laurdan is found to be more stable than Laurdan in the headgroup region of the membrane and also much more aligned with the lipids. This study suggests that, besides the lipid raft imaging, the C-Laurdan marker can considerably extend the capabilities of fluorescent solvent relaxation method.
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Affiliation(s)
- Justyna Barucha-Kraszewska
- Laboratoire de Nanomédecine, Imagerie et Thérapeutique, EA4662, Université de Franche-Comté, Centre Hospitalier Universitaire de Besançon, 16 Route de Gray, 25000 Besançon, France.
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Yesylevskyy SO, Demchenko AP. How cholesterol is distributed between monolayers in asymmetric lipid membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:1043-54. [DOI: 10.1007/s00249-012-0863-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 07/30/2012] [Accepted: 09/21/2012] [Indexed: 11/24/2022]
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39
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Demchenko AP. Beyond annexin V: fluorescence response of cellular membranes to apoptosis. Cytotechnology 2012; 65:157-72. [PMID: 22797774 DOI: 10.1007/s10616-012-9481-y] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 06/24/2012] [Indexed: 02/07/2023] Open
Abstract
Dramatic changes in the structure of cell membranes on apoptosis allow easy, sensitive and non-destructive analysis of this process with the application of fluorescence methods. The strong plasma membrane asymmetry is present in living cells, and its loss on apoptosis is commonly detected with the probes interacting strongly and specifically with phosphatidylserine (PS). This phospholipid becomes exposed to the cell surface, and the application of annexin V labeled with fluorescent dye is presently the most popular tool for its detection. Several methods have been suggested recently that offer important advantages over annexin V assay with the ability to study apoptosis by spectroscopy of cell suspensions, flow cytometry and confocal or two-photon microscopy. The PS exposure marks the integrated changes in the outer leaflet of cell membrane that involve electrostatic potential and hydration, and the attempts are being made to provide direct probing of these changes. This review describes the basic mechanisms underlying the loss of membrane asymmetry during apoptosis and discusses, in comparison with the annexin V-binding assay, the novel fluorescence techniques of detecting apoptosis on cellular membrane level. In more detail we describe the detection method based on smart fluorescent dye F2N12S incorporated into outer leaflet of cell membrane and reporting on apoptotic cell transformation by easily detectable change of the spectral distribution of fluorescent emission. It can be adapted to any assay format.
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Affiliation(s)
- Alexander P Demchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kiev, 01030, Ukraine,
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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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Demchenko AP. Modern views on the structure and dynamics of biological membranes. ACTA ACUST UNITED AC 2012. [DOI: 10.7124/bc.000029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- A. P. Demchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine
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43
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Jurkiewicz P, Cwiklik L, Jungwirth P, Hof M. Lipid hydration and mobility: An interplay between fluorescence solvent relaxation experiments and molecular dynamics simulations. Biochimie 2012; 94:26-32. [DOI: 10.1016/j.biochi.2011.06.027] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 06/23/2011] [Indexed: 11/29/2022]
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Orsi M, Essex JW. The ELBA force field for coarse-grain modeling of lipid membranes. PLoS One 2011; 6:e28637. [PMID: 22194874 PMCID: PMC3241685 DOI: 10.1371/journal.pone.0028637] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 11/11/2011] [Indexed: 02/05/2023] Open
Abstract
A new coarse-grain model for molecular dynamics simulation of lipid membranes is presented. Following a simple and conventional approach, lipid molecules are modeled by spherical sites, each representing a group of several atoms. In contrast to common coarse-grain methods, two original (interdependent) features are here adopted. First, the main electrostatics are modeled explicitly by charges and dipoles, which interact realistically through a relative dielectric constant of unity (ε(r) = 1). Second, water molecules are represented individually through a new parametrization of the simple Stockmayer potential for polar fluids; each water molecule is therefore described by a single spherical site embedded with a point dipole. The force field is shown to accurately reproduce the main physical properties of single-species phospholipid bilayers comprising dioleoylphosphatidylcholine (DOPC) and dioleoylphosphatidylethanolamine (DOPE) in the liquid crystal phase, as well as distearoylphosphatidylcholine (DSPC) in the liquid crystal and gel phases. Insights are presented into fundamental properties and phenomena that can be difficult or impossible to study with alternative computational or experimental methods. For example, we investigate the internal pressure distribution, dipole potential, lipid diffusion, and spontaneous self-assembly. Simulations lasting up to 1.5 microseconds were conducted for systems of different sizes (128, 512 and 1058 lipids); this also allowed us to identify size-dependent artifacts that are expected to affect membrane simulations in general. Future extensions and applications are discussed, particularly in relation to the methodology's inherent multiscale capabilities.
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Affiliation(s)
- Mario Orsi
- School of Chemistry, University of Southampton, Southampton, United Kingdom.
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Cwiklik L, Aquino AJA, Vazdar M, Jurkiewicz P, Pittner J, Hof M, Lischka H. Absorption and fluorescence of PRODAN in phospholipid bilayers: a combined quantum mechanics and classical molecular dynamics study. J Phys Chem A 2011; 115:11428-37. [PMID: 21910413 DOI: 10.1021/jp205966b] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Absorption and fluorescence spectra of PRODAN (6-propionyl-2-dimethylaminonaphthalene) were studied by means of the time-dependent density functional theory and the algebraic diagrammatic construction method. The influence of environment, a phosphatidylcholine lipid bilayer and water, was taken into account employing a combination of quantum chemical calculations with empirical force-field molecular dynamics simulations. Additionally, experimental absorption and emission spectra of PRODAN were measured in cyclohexane, water, and lipid vesicles. Both planar and twisted configurations of the first excited state of PRODAN were taken into account. The twisted structure is stabilized in both water and a lipid bilayer, and should be considered as an emitting state in polar environments. Orientation of the excited dye in the lipid bilayer significantly depends on configuration. In the bilayer, the fluorescence spectrum can be regarded as a combination of emission from both planar and twisted structures.
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Affiliation(s)
- Lukasz Cwiklik
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , v v i, Prague, Czech Republic.
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Robinson D, Besley NA, O'shea P, Hirst JD. Water order profiles on phospholipid/cholesterol membrane bilayer surfaces. J Comput Chem 2011; 32:2613-8. [DOI: 10.1002/jcc.21840] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 04/20/2011] [Accepted: 04/20/2011] [Indexed: 11/11/2022]
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47
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Yesylevskyy S, Savytskyi O, Odynets K, Kornelyuk A. Interdomain compactization in human tyrosyl-tRNA synthetase studied by the hierarchical rotations technique. Biophys Chem 2011; 154:90-8. [DOI: 10.1016/j.bpc.2011.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 12/21/2010] [Accepted: 01/17/2011] [Indexed: 10/18/2022]
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48
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Fluorescence Probing in Structurally Anisotropic Materials. ADVANCED FLUORESCENCE REPORTERS IN CHEMISTRY AND BIOLOGY III 2011. [DOI: 10.1007/978-3-642-18035-4_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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49
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Electrostatics of deformable lipid membranes. Biophys J 2010; 98:2904-13. [PMID: 20550903 DOI: 10.1016/j.bpj.2010.03.046] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 03/17/2010] [Accepted: 03/19/2010] [Indexed: 11/20/2022] Open
Abstract
It was recently demonstrated that significant local deformations of biological membranes take place due to the fields of charged peptides and ions, challenging the standard model of membrane electrostatics. The ability of ions to retain their immediate hydration environment, combined with the lack of sensitivity of permeability to ion type or even ion pairs, led us to question the extent to which hydration energetics and electrostatics control membrane ion permeation. Using the arginine analog methyl-guanidinium as a test case, we find that although hydrocarbon electronic polarizability causes dramatic changes in ion solvation free energy, as well as a significant change (approximately 0.4 V) in the membrane dipole potential, little change in membrane permeation energetics occurs. We attribute this to compensation of solvation terms from polar and polarizable nonpolar components within the membrane, and explain why the dipole potential is not fully sensed in terms of the locally deformed bilayer interface. Our descriptions provide a deeper understanding of the translocation process and allow predictions for poly-ions, ion pairs, charged lipids, and lipid flip-flop. We also report simulations of large hydrophobic-ion-like membrane defects and the ionophore valinomycin, which exhibit little membrane deformation, as well as hydrophilic defects and the ion channel gramicidin A, to provide parallels to membranes deformed by unassisted ion permeation.
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50
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Vorobyov I, Allen TW. The electrostatics of solvent and membrane interfaces and the role of electronic polarizability. J Chem Phys 2010. [DOI: 10.1063/1.3402125] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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