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Buta A, Nazaruk E, Dziubak D, Szewczyk A, Bilewicz R. Properties of electrode-supported lipid cubic mesophase films with embedded gramicidin A: structure and ion-transport studies. Bioelectrochemistry 2022; 144:108042. [PMID: 34942573 DOI: 10.1016/j.bioelechem.2021.108042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022]
Abstract
The lipid cubic phase (LCP) is a nanomaterial composed of water channels surrounded by lipid bilayers. LCPs are stable at room temperature and are biocompatible. These features make the lipid cubic phases similar to biological membranes, and hence, are favorable for embedding membrane proteins. We show that the monoolein cubic phase deposited on the electrode forms a 3D lipid bilayer film convenient for electrochemical investigations of membrane proteins. In this research, we studied the effect of embedding an ionophoric peptide, gramicidin A (gA), on the structure and properties of the LCP film. The phase identity and structural parameters of the gramicidin-doped phase were characterized by small-angle X-ray scattering (SAXS). The potassium ion transport through the film were studied by electroanalytical methods: alternating current voltammetry (ACV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Increased values for the current of the gramicidin-doped cubic phase compared to the empty cubic phase and changes of the EIS parameters confirmed that the peptide remained in the film in its active dimeric form. Our results show that the LCP can be considered a suitable 3D biomimetic film for the investigation of ion channels and other transporting membrane proteins, and for their application in electrochemical sensors.
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Affiliation(s)
- Aleksandra Buta
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland; Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Ewa Nazaruk
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Damian Dziubak
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Renata Bilewicz
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
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Guidelli R, Becucci L. Functional activity of peptide ion channels in tethered bilayer lipid membranes: Review. ELECTROCHEMICAL SCIENCE ADVANCES 2021. [DOI: 10.1002/elsa.202100180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Rolando Guidelli
- Department of Chemistry University of Florence Sesto Fiorentino Firenze Italy
| | - Lucia Becucci
- Ministero dell'Istruzione Scuola Media “Guglielmo Marconi” San Giovanni Valdarno Arezzo Italy
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Labbé E, Buriez O. Electrode‐supported and free‐standing bilayer lipid membranes: Formation and uses in molecular electrochemistry. ELECTROCHEMICAL SCIENCE ADVANCES 2021. [DOI: 10.1002/elsa.202100170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Eric Labbé
- PASTEUR Département de Chimie Ecole Normale Supérieure PSL University Sorbonne Université CNRS Paris 75005 France
| | - Olivier Buriez
- PASTEUR Département de Chimie Ecole Normale Supérieure PSL University Sorbonne Université CNRS Paris 75005 France
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Su Z, Goodall B, Leitch JJ, Lipkowski J. Ion transport mechanism in gramicidin A channels formed in floating bilayer lipid membranes supported on gold electrodes. Electrochim Acta 2021. [DOI: 10.1016/j.electacta.2021.137892] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Priske G, Su Z, Abbasi F, Lipkowski J, Auzanneau FI. Synthesis and electrochemical characterization of 4-thio pseudo-glycolipids as candidate tethers for lipid bilayer models. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2018.12.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Becucci L, Aloisi G, Papini AM, Guidelli R. Channel-forming activity of nisin in two mercury-supported biomimetic membranes. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2017.11.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Gramicidin A ion channel formation in model phospholipid bilayers tethered to gold (111) electrode surfaces. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.05.059] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Becucci L, Guidelli R. What Ion Flow along Ion Channels Can Tell us about Their Functional Activity. MEMBRANES 2016; 6:membranes6040053. [PMID: 27983579 PMCID: PMC5192409 DOI: 10.3390/membranes6040053] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 11/25/2016] [Accepted: 12/01/2016] [Indexed: 11/16/2022]
Abstract
The functional activity of channel-forming peptides and proteins is most directly verified by monitoring the flow of physiologically relevant inorganic ions, such as Na⁺, K⁺ and Cl-, along the ion channels. Electrical current measurements across bilayer lipid membranes (BLMs) interposed between two aqueous solutions have been widely employed to this end and are still extensively used. However, a major drawback of BLMs is their fragility, high sensitivity toward vibrations and mechanical shocks, and low resistance to electric fields. To overcome this problem, metal-supported tethered BLMs (tBLMs) have been devised, where the BLM is anchored to the metal via a hydrophilic spacer that replaces and mimics the water phase on the metal side. However, only mercury-supported tBLMs can measure and regulate the flow of the above inorganic ions, thanks to mercury liquid state and high hydrogen overpotential. This review summarizes the main results achieved by BLMs incorporating voltage-gated channel-forming peptides, interpreting them on the basis of a kinetic mechanism of nucleation and growth. Hg-supported tBLMs are then described, and their potential for the investigation of voltage-gated and ohmic channels is illustrated by the use of different electrochemical techniques.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia, 3, Sesto Fiorentino 50019, Italy.
| | - Rolando Guidelli
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia, 3, Sesto Fiorentino 50019, Italy.
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Becucci L, Aloisi G, Guidelli R. When and how the melittin ion channel exhibits ohmic behavior. Bioelectrochemistry 2016; 113:51-59. [PMID: 27732908 DOI: 10.1016/j.bioelechem.2016.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 11/15/2022]
Abstract
Melittin exhibits an ohmic behavior in a lipid bilayer having a DOPC distal leaflet and interposed between a 2.25nm tetraethyleneoxy chain tethered to a mercury drop and an aqueous solution. This behavior is induced in a pH6.8 buffer solution of 0.8μg/mL melittin by a pretreatment consisting of series of electrochemical impedance spectroscopy measurements at bias potentials varied by 50mV steps over a transmembrane potential range from about +250 to -250mV. This metastable ohmic behavior remains unchanged for hours, even after acidifying the solution to pH3. The midpoint potential E1/2 between the positive and negative peaks of the resulting cyclic voltammogram is almost coincident with that of the ohmic channels gramicidin and syringopeptin 25A and shifts by the same amount toward more positive potentials with a pH decrease from 6.8 to 3. This common cyclic voltammetry behavior is explained by a tilt of the DOPC polar heads around the channel mouth of these three peptides and is simulated by a modelistic approach. The ohmic behavior of melittin is explained by the persistence of the peptide orientation initially assumed at trans-negative potentials even after application of trans-positive ones, at sufficiently high peptide-to-lipid molar ratios.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry "Ugo Schiff", Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy.
| | - Giovanni Aloisi
- Department of Chemistry "Ugo Schiff", Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy
| | - Rolando Guidelli
- Department of Chemistry "Ugo Schiff", Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy.
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Becucci L, Toppi A, Fiore A, Scaloni A, Guidelli R. Channel-forming activity of syringopeptin 25A in mercury-supported phospholipid monolayers and negatively charged bilayers. Bioelectrochemistry 2016; 111:131-42. [DOI: 10.1016/j.bioelechem.2016.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 06/10/2016] [Accepted: 06/12/2016] [Indexed: 11/15/2022]
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Becucci L, Rossi M, Fiore A, Scaloni A, Guidelli R. Channel-forming activity of syringopeptin 25A in mercury-supported lipid bilayers with a phosphatidylcholine distal leaflet. Bioelectrochemistry 2016; 108:28-35. [DOI: 10.1016/j.bioelechem.2015.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/09/2015] [Accepted: 12/01/2015] [Indexed: 10/22/2022]
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Can gramicidin ion channel affect the dipole potential of neighboring phospholipid headgroups? Bioelectrochemistry 2015; 106:343-52. [DOI: 10.1016/j.bioelechem.2015.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/14/2015] [Accepted: 06/21/2015] [Indexed: 11/17/2022]
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Becucci L, Benci S, Nuti F, Real-Fernandez F, Vaezi Z, Stella L, Venanzi M, Rovero P, Papini AM. Interaction Study of Phospholipid Membranes with an N-Glucosylated β-Turn Peptide Structure Detecting Autoantibodies Biomarkers of Multiple Sclerosis. MEMBRANES 2015; 5:576-96. [PMID: 26437433 PMCID: PMC4704000 DOI: 10.3390/membranes5040576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 09/24/2015] [Indexed: 11/18/2022]
Abstract
The interaction of lipid environments with the type I’ β-turn peptide structure called CSF114 and its N-glucosylated form CSF114(Glc), previously developed as a synthetic antigenic probe recognizing specific autoantibodies in a subpopulation of multiple sclerosis patients’ serum, was investigated by fluorescence spectroscopy and electrochemical experiments using large unilamellar vesicles, mercury supported lipid self-assembled monolayers (SAMs) and tethered bilayer lipid membranes (tBLMs). The synthetic antigenic probe N-glucosylated peptide CSF114(Glc) and its unglucosylated form interact with the polar heads of lipid SAMs of dioleoylphosphatidylcholine at nonzero transmembrane potentials, probably establishing a dual electrostatic interaction of the trimethylammonium and phosphate groups of the phosphatidylcholine polar head with the Glu5 and His9 residues on the opposite ends of the CSF114(Glc) β-turn encompassing residues 6-9. His9 protonation at pH 7 eliminates this dual interaction. CSF114(Glc) is adsorbed on top of SAMs of mixtures of dioleoylphosphatidylcholine with sphingomyelin, an important component of myelin, whose proteins are hypothesized to undergo an aberrant N-glucosylation triggering the autoimmune response. Incorporation of the type I’ β-turn peptide structure CSF114 into lipid SAMs by potential scans of electrochemical impedance spectroscopy induces defects causing a slight permeabilization toward cadmium ions. The N-glucopeptide CSF114(Glc) does not affect tBLMs to a detectable extent.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy.
- Department of Chemistry, University of Padova, Via Marzolo 1, 35131 Padova, Italy.
| | - Stefano Benci
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
- Interdepartmental Laboratory of Peptide and Protein Chemistry and Biology, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
| | - Francesca Nuti
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
- Interdepartmental Laboratory of Peptide and Protein Chemistry and Biology, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
| | - Feliciana Real-Fernandez
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
- Interdepartmental Laboratory of Peptide and Protein Chemistry and Biology, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
| | - Zahra Vaezi
- Department of Chemical Sciences and Technologies, University of Rome 'Tor Vergata', Via Ricerca Scientifica 1, 00133 Rome, Italy
| | - Lorenzo Stella
- Department of Chemical Sciences and Technologies, University of Rome 'Tor Vergata', Via Ricerca Scientifica 1, 00133 Rome, Italy
| | - Mariano Venanzi
- Department of Chemical Sciences and Technologies, University of Rome 'Tor Vergata', Via Ricerca Scientifica 1, 00133 Rome, Italy
| | - Paolo Rovero
- Interdepartmental Laboratory of Peptide and Protein Chemistry and Biology, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
- Department of Neurosciences, Psychology, Drug Research and Child Health-Section of Pharmaceutical Sciences and Nutraceutics, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Anna Maria Papini
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
- Interdepartmental Laboratory of Peptide and Protein Chemistry and Biology, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
- PeptLab@UCP Platform and Laboratory of Chemical Biology EA4505, University of Cergy-Pontoise, 5 mail Gay-Lussac, 95031 Cergy-Pontoise CEDEX, France
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Becucci L, Tramonti V, Fiore A, Fogliano V, Scaloni A, Guidelli R. Channel-forming activity of syringomycin E in two mercury-supported biomimetic membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:932-41. [DOI: 10.1016/j.bbamem.2014.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/05/2014] [Accepted: 12/08/2014] [Indexed: 10/24/2022]
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Becucci L, Faragher RJ, Schwan A. The effect of the hydrophilic spacer length on the functionality of a mercury-supported tethered bilayer lipid membrane. Bioelectrochemistry 2014; 101:92-6. [PMID: 25180906 DOI: 10.1016/j.bioelechem.2014.08.012] [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: 06/19/2014] [Revised: 08/08/2014] [Accepted: 08/14/2014] [Indexed: 11/16/2022]
Abstract
A biomimetic membrane consisting of a thiolipid monolayer tethered to a mercury electrode, with a dioleoylphosphatidylcholine (DOPC) monolayer on top of it, was fabricated. The thiolipid, referred to as DPOL, consisted of an octaethyleneoxy (OEO) chain terminated at one end with a lipoic acid residue and covalently linked at the other end to two phytanyl chains. The functionality of this biomimetic membrane, referred to as a tethered bilayer lipid membrane (tBLM), was tested by incorporating gramicidin and alamethicin and verifying their ion channel activity. Advantages and drawbacks with respect to a tBLM using a thiolipid, referred to as DPTL, with a tetraethyleneoxy (TEO) chain were examined by using electrochemical impedance spectroscopy, potential-step chronocoulometry and cyclic voltammetry. The maximum charge surface density of potassium ions stored in the OEO spacer amounts to 70μCcm(-2), as compared to a charge surface density of 45μCcm(-2) in the TEO spacer. The lipid bilayer moiety of the DPOL/DOPC tBLM is somewhat leakier than that of the DPTL/DOPC tBLM at potentials negative of about -0.65V vs. the saturated calomel electrode. The estimated value of the surface dipole potential of the OEO spacer amounts to -0.180V and is, therefore, smaller than that, -0.230V, of the TEO spacer.
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Affiliation(s)
- Lucia Becucci
- Institute for the Chemistry of Organometallic Compounds (ICCOM) of the National Research Council, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze, Italy.
| | - Robert J Faragher
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Adrian Schwan
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Becucci L, Guidelli R, Polo F, Maran F. Interaction of mixed-ligand monolayer-protected Au₁₄₄ clusters with biomimetic membranes as a function of the transmembrane potential. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:8141-8151. [PMID: 24949655 DOI: 10.1021/la500909j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Understanding the interaction of nanoparticles with cell membranes is a high-priority research area for possible biomedical applications. We describe our findings concerning the interaction of Au144 monolayer-protected clusters (MPCs) with biomimetic membranes and their permeabilizing effect as a function of the transmembrane potential. We synthesized Au144(SCH2CH2Ph)60 and modified the capping monolayer with 8-mercaptooctanoic acid (Au144OctA) or thiolated trichogin (Au144TCG), a channel-forming peptide. The interactions of these MPCs with mercury-supported lipid mono- and bilayers were studied with a combination of electrochemical techniques specifically sensitive to changes in the properties of biomimetic membranes and/or charge-transfer phenomena. Permeabilization effects were evaluated through the influence of MPC uptake on the reduction of cadmium(II) ions. The nature and properties of the Au144 capping molecules play a crucial role in controlling how MPCs interact with membranes. The native MPC causes a small effect, whereas both Au144OctA and Au144TCG interact significantly with the lipid monolayer and show electroactivity. Whereas Au144OctA penetrates the membrane, Au144TCG pierces the membrane with its peptide appendage while remaining outside of it. Both clusters promote Cd(2+) reduction but with apparently different mechanisms. Because of the different way that they interact with the membrane, Au144OctA is more effective in Cd(2+) reduction when interacting with the lipid bilayer and Au144TCG performs particularly well when piercing the lipid monolayer.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry, Florence University , via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy
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Becucci L, Valensin D, Innocenti M, Guidelli R. Dermcidin, an anionic antimicrobial peptide: influence of lipid charge, pH and Zn2+ on its interaction with a biomimetic membrane. SOFT MATTER 2014; 10:616-626. [PMID: 24652391 DOI: 10.1039/c3sm52400k] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The mechanism of membrane permeabilization by dermcidin (DCD-1L), an antimicrobial peptide present in human sweat, was investigated at a mercury-supported monolayer of dioleoylphosphatidylcholine (DOPC) or dioleoylphosphatidylserine (DOPS) and at a mercury-supported tethered bilayer lipid membrane (tBLM) consisting of a thiolipid (DPTL) with a DOPC or DOPS monolayer self-assembled on top of it. In an unbuffered solution of pH 5.4, DCD-1L is almost neutral and permeabilizes a DPTL/DOPS tBLM at transmembrane potentials, ϕtrans, which are physiological. In a pH 7 buffer solution DCD-1L bears two negative charges and has no effect on a DPTL/DOPC tBLM, whereas it permeabilizes a DPTL/DOPS tBLM only outside the physiological ϕtrans range; however, the presence of zinc ion induces DCD-1L to permeabilize the DPTL/DOPS tBLM at physiological ϕtrans values. The effect of zinc ions suggests a DCD-1L conformation with its positive N-terminus embedded in the lipid bilayer and the negative C terminus floating on the membrane surface. This conformation can be stabilized by a zinc ion bridge between the His(38) residue of the C terminus and the carboxyl group of DOPS. Chronocoulometric potential jumps from ϕtrans ≅ +160 mV to sufficiently negative values yield charge transients exhibiting a sigmoidal shape preceded by a relatively long "foot". This behavior is indicative of ion-channel formation characterized by disruption of DCD-1L clusters adsorbed on top of the lipid bilayer, incorporation of the resulting monomers and their aggregation into hydrophilic pores by a mechanism of nucleation and growth.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry, Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy.
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Becucci L, Guidelli R. Mercury-supported biomimetic membranes for the investigation of antimicrobial peptides. Pharmaceuticals (Basel) 2014; 7:136-68. [PMID: 24463343 PMCID: PMC3942690 DOI: 10.3390/ph7020136] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 01/17/2014] [Indexed: 11/16/2022] Open
Abstract
Tethered bilayer lipid membranes (tBLMs) consist of a lipid bilayer interposed between an aqueous solution and a hydrophilic "spacer" anchored to a gold or mercury electrode. There is great potential for application of these biomimetic membranes for the elucidation of structure-function relationships of membrane peptides and proteins. A drawback in the use of mercury-supported tBLMs with respect to gold-supported ones is represented by the difficulty in applying surface sensitive, spectroscopic and scanning probe microscopic techniques to gather information on the architecture of these biomimetic membranes. Nonetheless, mercury-supported tBLMs are definitely superior to gold-supported biomimetic membranes for the investigation of the function of membrane peptides and proteins, thanks to a fluidity and lipid lateral mobility comparable with those of bilayer lipid membranes interposed between two aqueous phases (BLMs), but with a much higher robustness and resistance to electric fields. The different features of mercury-supported tBLMs reconstituted with functionally active membrane proteins and peptides of bacteriological or pharmacological interest may be disclosed by a judicious choice of the most appropriate electrochemical techniques. We will describe the way in which electrochemical impedance spectroscopy, potential-step chronocoulometry, cyclic voltammetry and phase-sensitive AC voltammetry are conveniently employed to investigate the structure of mercury-supported tBLMs and the mode of interaction of antimicrobial peptides reconstituted into them.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry "Ugo Schiff", Florence University, Via della Lastruccia 3, Sesto Fiorentino (Firenze) 50019, Italy.
| | - Rolando Guidelli
- Retired professor from Florence University, Firenze 50121, Italy.
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Biomimetic Membrane Supported at a Metal Electrode Surface. ADVANCES IN PLANAR LIPID BILAYERS AND LIPOSOMES 2014. [DOI: 10.1016/b978-0-12-418698-9.00001-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Becucci L, Innocenti M, Bellandi S, Guidelli R. Permeabilization of mercury-supported biomimetic membranes by amphotericin B and the role of calcium ions. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.09.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Becucci L, Foresti ML, Schwan A, Guidelli R. Can proton pumping by SERCA enhance the regulatory role of phospholamban and sarcolipin? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2682-90. [DOI: 10.1016/j.bbamem.2013.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/22/2013] [Accepted: 07/08/2013] [Indexed: 11/26/2022]
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Becucci L, Maran F, Guidelli R. Probing membrane permeabilization by the antibiotic lipopeptaibol trichogin GA IV in a tethered bilayer lipid membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1656-62. [DOI: 10.1016/j.bbamem.2012.03.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/16/2012] [Accepted: 03/30/2012] [Indexed: 10/28/2022]
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Probing membrane permeabilization by the antimicrobial peptide distinctin in mercury-supported biomimetic membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2745-52. [DOI: 10.1016/j.bbamem.2011.07.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 06/27/2011] [Accepted: 07/21/2011] [Indexed: 02/01/2023]
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Laredo T, Dutcher JR, Lipkowski J. Electric field driven changes of a gramicidin containing lipid bilayer supported on a Au(111) surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:10072-10087. [PMID: 21707110 DOI: 10.1021/la201625c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Langmuir-Blodgett and Langmuir-Schaeffer methods were employed to deposit a mixed bilayer consisting of 90% of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 10% of gramicidin (GD), a short 15 residue ion channel forming peptide, onto a Au(111) electrode surface. This architecture allowed us to investigate the effect of the electrostatic potential applied to the electrode on the orientation and conformation of DMPC molecules in the bilayer containing the ion channel. The charge density data were determined from chronocoulometry experiments. The electric field and the potential across the membrane were determined through the use of charge density curves. The magnitudes of potentials across the gold-supported biomimetic membrane were comparable to the transmembrane potential acting on a natural membrane. The information regarding the orientation and conformation of DMPC and GD molecules in the bilayer was obtained from photon polarization modulation infrared reflection absorption spectroscopy (PMIRRAS) measurements. The results show that the bilayer is adsorbed, in direct contact with the metal surface, when the potential across the interface is more positive than -0.4 V and is lifted from the gold surface when the potential across the interface is more negative than -0.4 V. This change in the state of the bilayer has a significant impact on the orientation and conformation of the phospholipid and gramicidin molecules. The potential induced changes in the membrane containing peptide were compared to the changes in the structure of the pure DMPC bilayer determined in earlier studies.
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Affiliation(s)
- Thamara Laredo
- Department of Chemistry, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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Becucci L, D'Amico M, Cinotti S, Daniele S, Guidelli R. Tethered bilayer lipid micromembranes for single-channel recording: the role of adsorbed and partially fused lipid vesicles. Phys Chem Chem Phys 2011; 13:13341-8. [PMID: 21701758 DOI: 10.1039/c1cp20667b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A mercury-supported bilayer lipid micromembrane was prepared by anchoring a thiolipid monolayer to a mercury cap electrodeposited on a platinum microdisc about 20 μm in diameter; a lipid monolayer was then self-assembled on top of the thiolipid monolayer either by vesicle fusion or by spilling a few drops of a lipid solution in chloroform on the cap and allowing the solvent to evaporate. Single-channel recording following incorporation of the alamethicin channel-forming peptide exhibits quite different features, depending on the procedure followed to form the distal lipid monolayer. The "spilling" procedure, which avoids the formation of adsorbed or partially fused vesicles, yields very sharp single-channel currents lasting only one or two milliseconds. These are ascribed to ionic flux into the hydrophilic spacer moiety of the thiolipid. Conversely, the vesicle-fusion procedure yields much longer single-channel openings analogous to those obtained with conventional bilayer lipid membranes, albeit smaller. This difference in behavior is explained by ascribing the latter single-channel currents to ionic flux into vesicles adsorbed and/or partially fused onto the tethered lipid bilayer, via capacitive coupling.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry, Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy.
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Bilayer lipid membranes supported on Teflon filters: A functional environment for ion channels. Biosens Bioelectron 2011; 26:3127-35. [DOI: 10.1016/j.bios.2010.12.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 12/05/2010] [Accepted: 12/07/2010] [Indexed: 11/18/2022]
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Abstract
This article describes efforts to build a model biological membrane at a surface of a gold electrode. In this architecture, the membrane may be exposed to static electric fields on the order of 10(7) to 10(8) V m(-1). These fields are comparable in magnitude to the static electric field acting on a natural biological membrane. The field may be conveniently used to manipulate organic molecules within the membrane. By turning a knob on the control instrument one can deposit or lift the membrane from the gold surface. Electrochemical techniques can be used to control the physical state of the film while the infrared reflection absorption spectroscopy (IRRAS), surface imaging by STM and AFM and neutron scattering techniques can be employed to study conformational changes of organic molecules and their ordering within the membrane. This is shown on examples of membranes built of a simple zwitterionic phospholipid such as 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) and a mixed membrane composed of DMPC and cholesterol. The results illustrate the tremendous effect of cholesterol on the membrane structure. Two methods of membrane deposition at the electrode surface, namely by unilamellar vesicles fusion and using the Langmuir-Blodgett technique, are compared. Applications of these model systems to study interactions of small antibiotic peptides with lipids are discussed.
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Affiliation(s)
- Jacek Lipkowski
- Department of Chemistry, University of Guelph, Guelph, Ontario, CanadaN1G 2W1.
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Becucci L, D'Amico M, Daniele S, Olivotto M, Pozzi A, Guidelli R. A metal-supported biomimetic micromembrane allowing the recording of single-channel activity and of impedance spectra of membrane proteins. Bioelectrochemistry 2009; 78:176-80. [PMID: 19726240 DOI: 10.1016/j.bioelechem.2009.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 08/09/2009] [Accepted: 08/11/2009] [Indexed: 10/20/2022]
Abstract
A novel tethered bilayer lipid micromembrane (tBLmicroM) was prepared and characterized. It consists of a mercury cap electrodeposited on a platinum microelectrode, about 20 microm in diameter. The micromembrane was prepared by tethering to the mercury cap a thiolipid monolayer and by then self-assembling a lipid monolayer on top of it. The thiolipid consisted of a disulfidated tetraoxyethylene hydrophilic spacer covalently linked to two phytanyl chains. Upon incorporating OmpF porin in the tBLmicroM, its single-channel activity was recorded by the patch-clamp technique, and its particular features described. An electrochemical impedance spectrum of the tBLmicroM incorporating OmpF porin is also reported. To the best of our knowledge, this tBLmicroM is the first metal-supported biomimetic micromembrane capable of incorporating non-engineered channel proteins in a functionally active state from their detergent solutions, and of allowing the recording of single-channel activity and of impedance spectra of these proteins via ion translocation into the hydrophilic spacer. The limited spaciousness of the spacer prevents a statistical analysis based on current-amplitude or blockage-time histograms. Nonetheless, the robustness, stability, ease of preparation and disposability of the present tBLmicroM may open the way to the realization of a channel-protein microarray platform allowing a high throughput drug screening.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry, Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy.
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Becucci L, Schwan AL, Sheepwash EE, Guidelli R. A new method to evaluate the surface dipole potential of thiol and disulfide self-assembled monolayers and its application to a disulfidated tetraoxyethylene glycol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:1828-1835. [PMID: 19170650 DOI: 10.1021/la803282w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A procedure to evaluate the surface dipole potential chi of thiol and disulfide self-assembled monolayers (SAMs) is described. The procedure consists of self-assembling the monolayers on a hanging mercury drop electrode and of measuring the charge involved in a progressive expansion of the mercury drop. This measurement is then combined with an estimate of the charge density q experienced by diffuse layer ions, obtained by measuring the diffuse layer capacitance of the SAM at different electrolyte concentrations by electrochemical impedance spectroscopy. These chi measurements, combined with chronocoulometric measurements of the total charge density sigma(M) against potential, indicate that SAMs of tetraoxyethylene glycol-D,L-alpha-lipoic acid ester (TEGL), 2,3-di-O-phytanyl-sn-glycerol-1-tetraoxyethylene glycol-D,L-alpha-lipoic ester (DPTL), and trioxyethyleneoxythiol (EO3) on mercury may undergo a reversal in the surface dipole potential of their polyoxyethylene chain with a change in the interfacial electric field. Moreover, TEGL and EO3 form stable SAMs without electron transfer to the metal, while no such conclusion can be drawn for DPTL.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry, Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy
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Potassium ion transport by gramicidin and valinomycin across a Ag(111)-supported tethered bilayer lipid membrane. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2008.04.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Faragher RJ, Schwan AL. New Deuterated Oligo(ethylene glycol) Building Blocks and Their Use in the Preparation of Surface Active Lipids Possessing Labeled Hydrophilic Tethers. J Org Chem 2008; 73:1371-8. [DOI: 10.1021/jo701979z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Robert J. Faragher
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Adrian L. Schwan
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Becucci L, Carbone MV, Biagiotti T, D'Amico M, Olivotto M, Guidelli R. Incorporation of the HERG potassium channel in a mercury supported lipid bilayer. J Phys Chem B 2008; 112:1315-9. [PMID: 18181608 DOI: 10.1021/jp077507h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The HERG potassium channel was incorporated in a mercury-supported tethered bilayer lipid membrane (tBLM) obtained by anchoring a thiolipid monolayer to the mercury surface and by self-assembling a lipid monolayer on top of it from a lipid film spread on the surface of an electrolyte solution. HERG was then incorporated in this tBLM from its micellar solution in Triton X-100, thus avoiding the use of vesicles in the preparation of the tBLM and of proteoliposomes in channel incorporation. The HERG "inward" current following a repolarization step was obtained by subtracting the current recorded upon addition of the specific inhibitor WAY from that recorded prior to this addition. This current was compared with that reported in the literature by the patch-clamp technique.
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Affiliation(s)
- Lucia Becucci
- Dipartimento di Chimica, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy.
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