1
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Enzyme activity of thiophene-fluorene based-copolymer blended with urease in thin films. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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2
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Hoareau E, Belley N, Klinker K, Desbat B, Boisselier É. Characterization of neurocalcin delta membrane binding by biophysical methods. Colloids Surf B Biointerfaces 2019; 174:291-299. [DOI: 10.1016/j.colsurfb.2018.11.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 11/02/2018] [Accepted: 11/07/2018] [Indexed: 01/19/2023]
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3
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Boisselier É, Demers É, Cantin L, Salesse C. How to gather useful and valuable information from protein binding measurements using Langmuir lipid monolayers. Adv Colloid Interface Sci 2017; 243:60-76. [PMID: 28372794 DOI: 10.1016/j.cis.2017.03.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 03/14/2017] [Accepted: 03/15/2017] [Indexed: 12/22/2022]
Abstract
This review presents data on the influence of various experimental parameters on the binding of proteins onto Langmuir lipid monolayers. The users of the Langmuir methodology are often unaware of the importance of choosing appropriate experimental conditions to validate the data acquired with this method. The protein Retinitis pigmentosa 2 (RP2) has been used throughout this review to illustrate the influence of these experimental parameters on the data gathered with Langmuir monolayers. The methods detailed in this review include the determination of protein binding parameters from the measurement of adsorption isotherms, infrared spectra of the protein in solution and in monolayers, ellipsometric isotherms and fluorescence micrographs.
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Affiliation(s)
- Élodie Boisselier
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
| | - Éric Demers
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Line Cantin
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Christian Salesse
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
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4
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Gragg M, Kim TG, Howell S, Park PSH. Wild-type opsin does not aggregate with a misfolded opsin mutant. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1850-9. [PMID: 27117643 DOI: 10.1016/j.bbamem.2016.04.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/06/2016] [Accepted: 04/13/2016] [Indexed: 10/21/2022]
Affiliation(s)
- Megan Gragg
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Tae Gyun Kim
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Scott Howell
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - P S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA.
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5
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Miller LM, Gragg M, Kim TG, Park PSH. Misfolded opsin mutants display elevated β-sheet structure. FEBS Lett 2015; 589:3119-25. [PMID: 26358292 DOI: 10.1016/j.febslet.2015.08.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 08/31/2015] [Indexed: 01/04/2023]
Abstract
Mutations in rhodopsin can cause misfolding and aggregation of the receptor, which leads to retinitis pigmentosa, a progressive retinal degenerative disease. The structure adopted by misfolded opsin mutants and the associated cell toxicity is poorly understood. Förster resonance energy transfer (FRET) and Fourier transform infrared (FTIR) microspectroscopy were utilized to probe within cells the structures formed by G188R and P23H opsins, which are misfolding mutants that cause autosomal dominant retinitis pigmentosa. Both mutants formed aggregates in the endoplasmic reticulum and exhibited altered secondary structure with elevated β-sheet and reduced α-helical content. The newly formed β-sheet structure may facilitate the aggregation of misfolded opsin mutants. The effects observed for the mutants were unrelated to retention of opsin molecules in the endoplasmic reticulum itself.
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Affiliation(s)
- Lisa M Miller
- National Synchrotron Light Source-II, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Megan Gragg
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
| | - Tae Gyun Kim
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA.
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6
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Qu G, Xue C, Han Y, Liang S, Cheng J, Ding W. Molecular Dynamics Study ofN-Dodecyl-N,N-Dimethyl-3-Ammonio-1-Propanesulfonate Mono-Layer Adsorbed at the Air/Water Interface. J DISPER SCI TECHNOL 2015. [DOI: 10.1080/01932691.2015.1080612] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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7
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Wang L, Roth JS, Han X, Evans SD. Photosynthetic Proteins in Supported Lipid Bilayers: Towards a Biokleptic Approach for Energy Capture. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:3306-3318. [PMID: 25727786 DOI: 10.1002/smll.201403469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/11/2015] [Indexed: 06/04/2023]
Abstract
In nature, plants and some bacteria have evolved an ability to convert solar energy into chemical energy usable by the organism. This process involves several proteins and the creation of a chemical gradient across the cell membrane. To transfer this process to a laboratory environment, several conditions have to be met: i) proteins need to be reconstituted into a lipid membrane, ii) the proteins need to be correctly oriented and functional and, finally, iii) the lipid membrane should be capable of maintaining chemical and electrical gradients. Investigating the processes of photosynthesis and energy generation in vivo is a difficult task due to the complexity of the membrane and its associated proteins. Solid, supported lipid bilayers provide a good model system for the systematic investigation of the different components involved in the photosynthetic pathway. In this review, the progress made to date in the development of supported lipid bilayer systems suitable for the investigation of membrane proteins is described; in particular, there is a focus on those used for the reconstitution of proteins involved in light capture.
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Affiliation(s)
- Lei Wang
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- State Key Laboratory of Urban Water Resource and Environment, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, 150001, China
| | - Johannes S Roth
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, 150001, China
| | - Stephen D Evans
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
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8
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Demers É, Boisselier É, Horchani H, Blaudez D, Calvez P, Cantin L, Belley N, Champagne S, Desbat B, Salesse C. Lipid Selectivity, Orientation, and Extent of Membrane Binding of Nonacylated RP2. Biochemistry 2015; 54:2560-70. [DOI: 10.1021/bi501517r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Éric Demers
- CUO-Recherche,
Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec
and Département d’ophtalmologie, Faculté de médecine,
and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Élodie Boisselier
- CUO-Recherche,
Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec
and Département d’ophtalmologie, Faculté de médecine,
and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Habib Horchani
- CUO-Recherche,
Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec
and Département d’ophtalmologie, Faculté de médecine,
and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Daniel Blaudez
- CBMN-UMR
5248 CNRS, Université de Bordeaux, IPB, Allée Geoffroy
Saint Hilaire, 33600 Pessac, France
| | - Philippe Calvez
- CUO-Recherche,
Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec
and Département d’ophtalmologie, Faculté de médecine,
and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Line Cantin
- CUO-Recherche,
Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec
and Département d’ophtalmologie, Faculté de médecine,
and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Nicolas Belley
- CUO-Recherche,
Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec
and Département d’ophtalmologie, Faculté de médecine,
and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Sophie Champagne
- CUO-Recherche,
Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec
and Département d’ophtalmologie, Faculté de médecine,
and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Bernard Desbat
- CBMN-UMR
5248 CNRS, Université de Bordeaux, IPB, Allée Geoffroy
Saint Hilaire, 33600 Pessac, France
| | - Christian Salesse
- CUO-Recherche,
Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec
and Département d’ophtalmologie, Faculté de médecine,
and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
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9
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Lhor M, Méthot M, Horchani H, Salesse C. Structure of the N-terminal segment of human retinol dehydrogenase 11 and its preferential lipid binding using model membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:878-85. [DOI: 10.1016/j.bbamem.2014.12.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 12/09/2014] [Accepted: 12/15/2014] [Indexed: 11/25/2022]
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10
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Yan ECY, Wang Z, Fu L. Proteins at Interfaces Probed by Chiral Vibrational Sum Frequency Generation Spectroscopy. J Phys Chem B 2015; 119:2769-85. [DOI: 10.1021/jp508926e] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Elsa C. Y. Yan
- Department of Chemistry, Yale University, New Haven, CT 06511, United States
| | - Zhuguang Wang
- Department of Chemistry, Yale University, New Haven, CT 06511, United States
| | - Li Fu
- Department of Chemistry, Yale University, New Haven, CT 06511, United States
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11
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Visualizing a multidrug resistance protein, EmrE, with major bacterial lipids using Brewster angle microscopy. Chem Phys Lipids 2013; 167-168:33-42. [DOI: 10.1016/j.chemphyslip.2013.01.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 12/22/2012] [Accepted: 01/18/2013] [Indexed: 11/17/2022]
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12
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Shen HH, Lithgow T, Martin LL. Reconstitution of membrane proteins into model membranes: seeking better ways to retain protein activities. Int J Mol Sci 2013; 14:1589-607. [PMID: 23344058 PMCID: PMC3565336 DOI: 10.3390/ijms14011589] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 02/01/2023] Open
Abstract
The function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. The activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. The reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. However, the activity of membrane proteins is often difficult to sustain following reconstitution, since the composition of the model phospholipid bilayer differs from that of the native cell membrane. This review will discuss the reconstitution of membrane protein activities in four different types of model membrane - monolayers, supported lipid bilayers, liposomes and nanodiscs, comparing their advantages in membrane protein reconstitution. Variation in the surrounding model environments for these four different types of membrane layer can affect the three-dimensional structure of reconstituted proteins and may possibly lead to loss of the proteins activity. We also discuss examples where the same membrane proteins have been successfully reconstituted into two or more model membrane systems with comparison of the observed activity in each system. Understanding of the behavioral changes for proteins in model membrane systems after membrane reconstitution is often a prerequisite to protein research. It is essential to find better solutions for retaining membrane protein activities for measurement and characterization in vitro.
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Affiliation(s)
- Hsin-Hui Shen
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800, Australia; E-Mail:
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +61-3-9545-8159
| | - Trevor Lithgow
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800, Australia; E-Mail:
| | - Lisandra L. Martin
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia; E-Mail:
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13
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Bussières S, Cantin L, Desbat B, Salesse C. Binding of a truncated form of lecithin:retinol acyltransferase and its N- and C-terminal peptides to lipid monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:3516-3523. [PMID: 22260449 DOI: 10.1021/la203896n] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Lecithin:retinol acyltransferase (LRAT) is a 230 amino acid membrane-associated protein which catalyzes the esterification of all-trans-retinol into all-trans-retinyl ester. A truncated form of LRAT (tLRAT), which contains the residues required for catalysis but which is lacking the N- and C-terminal hydrophobic segments, was produced to study its membrane binding properties. Measurements of the maximum insertion pressure of tLRAT, which is higher than the estimated lateral pressure of membranes, and the positive synergy factor a argue in favor of a strong binding of tLRAT to phospholipid monolayers. Moreover, the binding, secondary structure and orientation of the peptides corresponding to its N- and C-terminal hydrophobic segments of LRAT have been studied by circular dichroism and polarization-modulation infrared reflection absorption spectroscopy in monolayers. The results show that these peptides spontaneously bind to lipid monolayers and adopt an α-helical secondary structure. On the basis of these data, a new membrane topology model of LRAT is proposed where its N- and C-terminal segments allow to anchor this protein to the lipid bilayer.
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Affiliation(s)
- Sylvain Bussières
- LOEX/CUO-recherche, Centre hospitalier affilié universitaire de Québec, Hôpital du Saint-Sacrement, 1050 Chemin Ste-Foy, Québec (Québec), Canada
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14
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Larsson K, Quinn P, Sato K, Tiberg F. Interaction of lipids with proteins and polypeptides. Lipids 2012. [DOI: 10.1533/9780857097910.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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15
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Gröger T, Nathoo S, Ku T, Sikora C, Turner RJ, Prenner EJ. Real-time imaging of lipid domains and distinct coexisting membrane protein clusters. Chem Phys Lipids 2011; 165:216-24. [PMID: 22227110 DOI: 10.1016/j.chemphyslip.2011.12.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 12/15/2011] [Accepted: 12/19/2011] [Indexed: 12/20/2022]
Abstract
A detailed understanding of biomembrane architecture is still a challenging task. Many in vitro studies have shown lipid domains but much less information is known about the lateral organization of membrane proteins because their hydrophobic nature limits the use of many experimental methods. We examined lipid domain formation in biomimetic Escherichia coli membranes composed of phosphatidylethanolamine and phosphatidylglycerol in the absence and presence of 1% and 5% (mol/mol) membrane multidrug resistance protein, EmrE. Monolayer isotherms demonstrated protein insertion into the lipid monolayer. Subsequently, Brewster angle microscopy was applied to image domains in lipid matrices and lipid-protein mixtures. The images showed a concentration dependent impact of the protein on lipid domain size and shape and more interestingly distinct coexisting protein clusters. Whereas lipid domains varied in size (14-47μm), protein clusters exhibited a narrow size distribution (2.6-4.8μm) suggesting a non-random process of cluster formation. A 3-D display clearly indicates that these proteins clusters protrude from the membrane plane. These data demonstrate distinct co-existing lipid domains and membrane protein clusters as the monofilm is being compressed and illustrate the significant mutual impact of lipid-protein interactions on lateral membrane architecture.
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Affiliation(s)
- Thomas Gröger
- Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherbeg, Germany
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16
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Fu L, Wang Z, Yan EC. Chiral vibrational structures of proteins at interfaces probed by sum frequency generation spectroscopy. Int J Mol Sci 2011; 12:9404-25. [PMID: 22272140 PMCID: PMC3257137 DOI: 10.3390/ijms12129404] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 12/13/2011] [Accepted: 12/13/2011] [Indexed: 12/04/2022] Open
Abstract
We review the recent development of chiral sum frequency generation (SFG) spectroscopy and its applications to study chiral vibrational structures at interfaces. This review summarizes observations of chiral SFG signals from various molecular systems and describes the molecular origins of chiral SFG response. It focuses on the chiral vibrational structures of proteins and presents the chiral SFG spectra of proteins at interfaces in the C-H stretch, amide I, and N-H stretch regions. In particular, a combination of chiral amide I and N-H stretches of the peptide backbone provides highly characteristic vibrational signatures, unique to various secondary structures, which demonstrate the capacity of chiral SFG spectroscopy to distinguish protein secondary structures at interfaces. On the basis of these recent developments, we further discuss the advantages of chiral SFG spectroscopy and its potential application in various fields of science and technology. We conclude that chiral SFG spectroscopy can be a new approach to probe chiral vibrational structures of protein at interfaces, providing structural and dynamic information to study in situ and in real time protein structures and dynamics at interfaces.
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Affiliation(s)
- Li Fu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06520, USA; E-Mails: (L.F.); (Z.W.)
| | - Zhuguang Wang
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06520, USA; E-Mails: (L.F.); (Z.W.)
| | - Elsa C.Y. Yan
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06520, USA; E-Mails: (L.F.); (Z.W.)
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17
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Hoernke M, Falenski JA, Schwieger C, Koksch B, Brezesinski G. Triggers for β-sheet formation at the hydrophobic-hydrophilic interface: high concentration, in-plane orientational order, and metal ion complexation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:14218-14231. [PMID: 22011020 DOI: 10.1021/la203016z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Amyloid formation plays a causative role in neurodegenerative diseases such as Alzheimer's disease or Parkinson's disease. Soluble peptides form β-sheets that subsequently rearrange into fibrils and deposit as amyloid plaques. Many parameters trigger and influence the onset of the β-sheet formation. Early stages are recently discussed to be cell-toxic. Aiming at understanding various triggers such as interactions with hydrophobic-hydrophilic interfaces and metal ion complexation and their interplay, we investigated a set of model peptides at the air-water interface. We are using a general approach to a variety of diseases such as Alzheimer's disease, Parkinson's disease, and type II diabetes that are connected to amyloid formation. Surface sensitive techniques combined with film balance measurements have been used to assess the conformation of the peptides and their orientation at the air-water interface (IR reflection-absorption spectroscopy). Additionally, the structures of the peptide layers were characterized by grazing incidence X-ray diffraction and X-ray reflectivity. The peptides adsorb to the air-water interface and immediately adopt an α-helical conformation. This helical intermediate transforms into β-sheets upon further triggering. The factors that result in β-sheet formation are dependent on the peptide sequence. In general, the interface has the strongest effect on peptide conformation compared to high concentrations or metal ions. Metal ions are able to prevent aggregation in bulk but not at the interface. At the interface, metal ion complexation has only minor effects on the peptide secondary structure, influencing the in-plane structure that is formed in two dimensions. At the air-water interface, increased concentrations or a parallel arrangement of the α-helical intermediates are the most effective triggers. This study reveals the role of various triggers for β-sheet formation and their complex interplay. Our main finding is that the hydrophobic-hydrophilic interface largely governs the conformation of peptides. Therefore, the present study implies that special care is needed when interpreting data that may be affected by different amounts or types of interfaces during experimentation.
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Affiliation(s)
- Maria Hoernke
- Department of Interfaces, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany
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18
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Yan H, Guo XL, Yuan SL, Liu CB. Molecular dynamics study of the effect of calcium ions on the monolayer of SDC and SDSn surfactants at the vapor/liquid interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5762-5771. [PMID: 21495650 DOI: 10.1021/la1049869] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The effect of Ca(2+) ions on the hydration shell of sodium dodecyl carboxylate (SDC) and sodium dodecyl sulfonate (SDSn) monolayer at vapor/liquid interfaces was studied using molecular dynamics simulations. For each surfactant, two different surface concentrations were used to perform the simulations, and the aggregation morphologies and structural details have been reported. The results showed that the aggregation structures relate to both the surface coverage and the calcium ions. The divalent ions can screen the interaction between the polar head and Na(+) ions. Thus, Ca(2+) ions locate near the vapor/liquid interface to bind to the headgroup, making the aggregations much more compact via the salt bridge. The potential of mean force (PMF) between Ca(2+) and the headgroups shows that the interaction is decided by a stabilizing solvent-separated minimum in the PMF. To bind to the headgroup, Ca(2+) should overcome the energy barrier. Among contributions to the PMF, the major repulsive interaction was due to the rearrangement of the hydration shell after the calcium ions entered into the hydration shell of the headgroup. The PMFs between the headgroup and Ca(2+) in the SDSn systems showed higher energy barriers than those in the SDC systems. This result indicated that SDSn binds the divalent ions with more difficulty compared with SDC, so the ions have a strong effect on the hydration shell of SDC. That is why sulfonate surfactants have better efficiency in salt solutions with Ca(2+) ions for enhanced oil recovery.
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Affiliation(s)
- Hui Yan
- Key Lab of Colloid and Interface Chemistry, Shandong University, Jinan 250100, China
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19
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Fu L, Liu J, Yan ECY. Chiral Sum Frequency Generation Spectroscopy for Characterizing Protein Secondary Structures at Interfaces. J Am Chem Soc 2011; 133:8094-7. [DOI: 10.1021/ja201575e] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Li Fu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Jian Liu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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20
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Korchowiec B, Orlof M, Sautrey G, Ben Salem A, Korchowiec J, Regnouf-de-Vains JB, Rogalska E. The Mechanism of Metal Cation Binding in Two Nalidixate Calixarene Conjugates. A Langmuir Film and Molecular Modeling Study. J Phys Chem B 2010; 114:10427-35. [DOI: 10.1021/jp102471c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Beata Korchowiec
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland, Equipe GEVSM, Structure et Réactivité des Systèmes Moléculaires Complexes, UMR 7565 Nancy Université/CNRS, BP 239, 54506 Vandoeuvre-lès-Nancy cedex, France, and Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland
| | - Monika Orlof
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland, Equipe GEVSM, Structure et Réactivité des Systèmes Moléculaires Complexes, UMR 7565 Nancy Université/CNRS, BP 239, 54506 Vandoeuvre-lès-Nancy cedex, France, and Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland
| | - Guillaume Sautrey
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland, Equipe GEVSM, Structure et Réactivité des Systèmes Moléculaires Complexes, UMR 7565 Nancy Université/CNRS, BP 239, 54506 Vandoeuvre-lès-Nancy cedex, France, and Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland
| | - Adel Ben Salem
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland, Equipe GEVSM, Structure et Réactivité des Systèmes Moléculaires Complexes, UMR 7565 Nancy Université/CNRS, BP 239, 54506 Vandoeuvre-lès-Nancy cedex, France, and Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland
| | - Jacek Korchowiec
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland, Equipe GEVSM, Structure et Réactivité des Systèmes Moléculaires Complexes, UMR 7565 Nancy Université/CNRS, BP 239, 54506 Vandoeuvre-lès-Nancy cedex, France, and Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland
| | - Jean-Bernard Regnouf-de-Vains
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland, Equipe GEVSM, Structure et Réactivité des Systèmes Moléculaires Complexes, UMR 7565 Nancy Université/CNRS, BP 239, 54506 Vandoeuvre-lès-Nancy cedex, France, and Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland
| | - Ewa Rogalska
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland, Equipe GEVSM, Structure et Réactivité des Systèmes Moléculaires Complexes, UMR 7565 Nancy Université/CNRS, BP 239, 54506 Vandoeuvre-lès-Nancy cedex, France, and Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, ul. R. Ingardena 3, 30-060 Krakow, Poland
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Vié V, Legardinier S, Chieze L, Le Bihan O, Qin Y, Sarkis J, Hubert JF, Renault A, Desbat B, Le Rumeur E. Specific anchoring modes of two distinct dystrophin rod sub-domains interacting in phospholipid Langmuir films studied by atomic force microscopy and PM-IRRAS. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1503-11. [PMID: 20399196 DOI: 10.1016/j.bbamem.2010.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 04/02/2010] [Accepted: 04/07/2010] [Indexed: 11/29/2022]
Abstract
Dystrophin rod repeats 1-3 sub-domain binds to acidic phosphatidylserine in a small vesicle binding assay, while the repeats 20-24 sub-domain does not. In the present work, we studied the adsorption behaviour of both sub-domains at the air/liquid interface and at the air/lipid interface in a Langmuir trough in order to highlight differences in interfacial properties. The adsorption behaviour of the two proteins at the air/liquid interface shows that they display surface activity while maintaining their alpha-helical secondary structure as shown by PM-IRRAS. Strikingly, R20-24 needs to be highly hydrated even at the interface, while this is not the case for R1-3, indicating that the surface activity is dramatically higher for R1-3 than R20-24. Surface-pressure measurements, atomic force microscopy and PM-IRRAS are used in a Langmuir experiment with DOPC-DOPS monolayers at two different surface pressures, 20 mN/m and 30 mN/m. At the lower surface pressure, the proteins are adsorbed at the lipid film interface while maintaining its alpha-helical structure. After an increase of the surface pressure, R1-3 subsequently produces a stable film, while R20-24 induces a reorganization of the lipid film with a subsequent decrease of the surface pressure close to the initial value. AFM and PM-IRRAS show that R1-3 is present in high amounts at the interface, being arranged in clusters representing 3.3% of the surface at low pressure. By contrast, R20-24 is present at the interface in small amounts bound only by a few electrostatic residues to the lipid film while the major part of the molecule remains floating in the sub-phase. Then for R1-3, the electrostatic interaction between the proteins and the film is enhanced by hydrophobic interactions. At higher surface pressure, the number of protein clusters increases and becomes closer in both cases implying the electrostatic character of the binding. These results indicate that even if the repeats exhibit large structural similarities, their interfacial properties are highly contrasted by their differential anchor mode in the membrane. Our work provides strong support for distinct physiological roles for the spectrin-like repeats and may partly explain the effects of therapeutic replacement of dystrophin deficiency by minidystrophins.
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Affiliation(s)
- V Vié
- Université de Rennes 1, Institut de Physique UMR CNRS 6251, Rennes, France.
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22
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Influence of the hydrophobic interface and transition metal ions on the conformation of amyloidogenic model peptides. Biophys Chem 2010; 150:64-72. [PMID: 20347516 DOI: 10.1016/j.bpc.2010.02.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 02/18/2010] [Accepted: 02/20/2010] [Indexed: 10/19/2022]
Abstract
The transition of alpha-helical or unfolded peptides and proteins to beta-sheets and the subsequent amyloid formation are characteristic for neurodegenerative diseases like Alzheimer's or Parkinson's disease. The interactions of amyloidogenic peptides with surfaces such as biological membranes are considered to play an important role regarding the onset of secondary structure changes. In our project, we used a peptide designed to have specific secondary structure propensities in order to investigate the driving forces and conditions which lead to the beta-sheet formation. The model peptide is able to adopt the coiled coil conformation, alpha-helical peptide strands that wind around each other in a superhelical structure. In addition to building principles stabilizing this alpha-helical conformation it also has beta-sheet stabilizing features. We focused on the interactions of the peptide with the hydrophobic air-water interface. Infrared reflection absorption spectroscopy was used as a surface sensitive method and complemented with grazing incidence X-ray diffraction and reflectivity. Furthermore, the model peptide provides metal binding sites. The binding of transition metal ions leads to a local preference of certain secondary structure elements, depending on the metal ion and the geometry of metal ion binding sites. The interplay and competition of the two trigger mechanisms (1) interaction with surfaces and (2) metal ion complexation were investigated. We found that the secondary structure of the peptide strongly depends on the interactions with the hydrophobic air-water interface and the orientation imposed by it. The metal ions Zn(2+) and Cu(2+) were used for complexation. The structure of the peptide surface layer differs according to the bound metal ion.
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23
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Phospholipid monolayer hydrolysis by cytosolic phospholipase A2 gamma and lecithin retinol acyl transferase. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2007.11.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Bussières S, Buffeteau T, Desbat B, Breton R, Salesse C. Secondary structure of a truncated form of lecithin retinol acyltransferase in solution and evidence for its binding and hydrolytic action in monolayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1324-34. [PMID: 18284914 DOI: 10.1016/j.bbamem.2008.01.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 01/24/2008] [Accepted: 01/25/2008] [Indexed: 10/22/2022]
Abstract
Lecithin retinol acyltransferase (LRAT) is a 230 amino acids membrane-associated protein which catalyzes the esterification of all-trans-retinol into all-trans-retinyl ester. The enzymatic activity of a truncated form of LRAT (tLRAT) which contains the residues required for catalysis but which is lacking N- and C-terminal hydrophobic segments has been shown to depend on the detergent used for its solubilization. Moreover, it is unknown whether tLRAT can bind membranes in the absence of these hydrophobic segments. The present study has allowed to measure the membrane binding and hydrolytic action of tLRAT in lipid monolayers by use of polarization modulation infrared reflection absorption spectroscopy and Brewster angle microscopy. Moreover, the proportion of the secondary structure components of tLRAT was determined in three different detergents by infrared absorption spectroscopy, vibrational circular dichroism and electronic circular dichroism which allowed to explain its detergent dependent activity. In addition, the secondary structure of tLRAT in the absence of detergent was very similar to that in Triton X-100 thus suggesting that, compared to the other detergents assayed, the secondary structure of this protein is very little perturbed by this detergent.
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Affiliation(s)
- Sylvain Bussières
- Unité de recherche en ophtalmologie, Centre Hospitalier Universitaire de Québec, Pavillon CHUL, Département d'ophtalmologie, Faculté de médecine, Université Laval, 2705 Blvd. Laurier, Ste-Foy, Québec, Canada G1V 4G2
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25
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Desmeules P, Penney SE, Desbat B, Salesse C. Determination of the contribution of the myristoyl group and hydrophobic amino acids of recoverin on its dynamics of binding to lipid monolayers. Biophys J 2007; 93:2069-82. [PMID: 17526567 PMCID: PMC1959526 DOI: 10.1529/biophysj.106.103481] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 05/17/2007] [Indexed: 01/16/2023] Open
Abstract
It has been postulated that myristoylation of peripheral proteins would facilitate their binding to membranes. However, the exact involvement of this lipid modification in membrane binding is still a matter of debate. Proteins containing a Ca(2+)-myristoyl switch where the extrusion of their myristoyl group is dependent on calcium binding is best illustrated by the Ca(2+)-binding recoverin, which is present in retinal rod cells. The parameters responsible for the modulation of the membrane binding of recoverin are still largely unknown. This study was thus performed to determine the involvement of different parameters on recoverin membrane binding. We have used surface pressure measurements and PM-IRRAS spectroscopy to monitor the adsorption of myristoylated and nonmyristoylated recoverin onto phospholipid monolayers in the presence and absence of calcium. The adsorption curves have shown that the myristoyl group and hydrophobic residues of myristoylated recoverin strongly accelerate membrane binding in the presence of calcium. In the case of nonmyristoylated recoverin in the presence of calcium, hydrophobic residues alone are responsible for its much faster monolayer binding than myristoylated and nonmyristoylated recoverin in the absence of calcium. The infrared spectra revealed that myristoylated and nonmyristoylated recoverin behave very different upon adsorption onto phospholipid monolayers. Indeed, PM-IRRAS spectra indicated that the myristoyl group allows a proper orientation and organization as well as faster and stronger binding of myristoylated recoverin to lipid monolayers compared to nonmyristoylated recoverin. Simulations of the spectra have allowed us to postulate that nonmyristoylated recoverin changes conformation and becomes hydrated at large extents of adsorption as well as to estimate the orientation of myristoylated recoverin with respect to the monolayer plane. In addition, adsorption measurements and electrophoresis of trypsin-treated myristoylated recoverin in the presence of zinc or calcium demonstrated that recoverin has a different conformation but a similar extent of monolayer binding in the presence of such ions.
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Affiliation(s)
- Philippe Desmeules
- Unité de Recherche en Opthalmologie, Centre Hospitalier Universitaire de Québec, Pavillon CHUL, and Département d'Opthalmologie, Faculté de Médecine, Université Laval, Québec, Canada
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26
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Boucher J, Trudel E, Méthot M, Desmeules P, Salesse C. Organization, structure and activity of proteins in monolayers. Colloids Surf B Biointerfaces 2007; 58:73-90. [PMID: 17509839 DOI: 10.1016/j.colsurfb.2007.03.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 03/24/2007] [Accepted: 03/26/2007] [Indexed: 12/17/2022]
Abstract
Many different processes take place at the cell membrane interface. Indeed, for instance, ligands bind membrane proteins which in turn activate peripheral membrane proteins, some of which are enzymes whose action is also located at the membrane interface. Native cell membranes are difficult to use to gain information on the activity of individual proteins at the membrane interface because of the large number of different proteins involved in membranous processes. Model membrane systems, such as monolayers at the air-water interface, have thus been extensively used during the last 50 years to reconstitute proteins and to gain information on their organization, structure and activity in membranes. In the present paper, we review the recent work we have performed with membrane and peripheral proteins as well as enzymes in monolayers at the air-water interface. We show that the structure and orientation of gramicidin has been determined by combining different methods. Furthermore, we demonstrate that the secondary structure of rhodopsin and bacteriorhodopsin is indistinguishable from that in native membranes when appropriate conditions are used. We also show that the kinetics and extent of monolayer binding of myristoylated recoverin is much faster than that of the nonmyristoylated form and that this binding is highly favored by the presence polyunsaturated phospholipids. Moreover, we show that the use of fragments of RPE65 allow determine which region of this protein is most likely involved in membrane binding. Monomolecular films were also used to further understand the hydrolysis of organized phospholipids by phospholipases A2 and C.
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Affiliation(s)
- Julie Boucher
- Unité de recherche en ophtalmologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec and Département d'Ophtalmologie, Faculté de médecine, Université Laval, Québec, Que. G1V 4G2, Canada
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27
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Baszkin A. Molecular recognition on the supported and on the air/water interface-spread protein monolayers. Adv Colloid Interface Sci 2006; 128-130:111-20. [PMID: 17196538 DOI: 10.1016/j.cis.2006.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Targeting of proteins at interfaces via affinity ligands or specific antibodies is important for the understanding of protein functioning in biological membranes. This review brings together a great number of research works accomplished in this field in the past decade by a variety of analytical methods. It highlights two simple in situ techniques of monitoring molecular recognition processes at interfaces recently developed in the author's laboratory. The first of these techniques is based on the measurements of surface pressure increments of a protein monolayer spread at the air/water interface at a constant area resulting from the interaction with its specific ligands injected into the aqueous subphase beneath the preformed protein monolayer. The second technique takes advantage of the feature of [(14)C]-labeled proteins that enable in situ measurements of surface density changes of adsorbed protein molecules on a solid support resulting from the interaction with its specific antibody.
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Affiliation(s)
- Adam Baszkin
- Physico-Chimie des Surfaces, UMR CNRS 8612, Université Paris-Sud, 92296 Châtenay-Melabry Cedex, France.
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28
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Yuan S, Ma L, Zhang X, Zheng L. Molecular dynamics studies on monolayer of cetyltrimethylammonium bromide surfactant formed at the air/water interface. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2006.03.055] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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29
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Xu YY, Bian C, Chen S, Xia S. A microelectronic technology based amperometric immunosensor for α-fetoprotein using mixed self-assembled monolayers and gold nanoparticles. Anal Chim Acta 2006. [DOI: 10.1016/j.aca.2005.12.061] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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30
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Hou Y, Helali S, Zhang A, Jaffrezic-Renault N, Martelet C, Minic J, Gorojankina T, Persuy MA, Pajot-Augy E, Salesse R, Bessueille F, Samitier J, Errachid A, Akimov V, Reggiani L, Pennetta C, Alfinito E. Immobilization of rhodopsin on a self-assembled multilayer and its specific detection by electrochemical impedance spectroscopy. Biosens Bioelectron 2006; 21:1393-402. [PMID: 16043336 DOI: 10.1016/j.bios.2005.06.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Revised: 05/16/2005] [Accepted: 06/13/2005] [Indexed: 11/30/2022]
Abstract
Rhodopsin, the G protein-coupled receptor (GPCR) which mediates the sense of vision, was prepared from calf eyes and used as receptor enriched membrane fraction. In this study it was immobilized onto gold electrode by two different techniques: Langmuir-Blodgett (LB) and a strategy based on a self-assembled multilayer. We demonstrated that Langmuir and LB films of rhodopsin are not stable. Thus, in this study a new protein multilayer was prepared on gold electrode by building up layer-by-layer a self-assembled multilayer. It is composed of a mixed self-assembled monolayer formed by MHDA and biotinyl-PE, followed by a biotin-avidin system which allows binding of biotinylated antibody specific to rhodopsin. The immobilization of rhodopsin in membrane fraction, by the specific antibody bound previously on self-assembled multilayer, was monitored with electrochemical impedance spectroscopy (EIS). In addition, the specificity and sensitivity of this self-assembled multilayer system to the presence of rhodopsin were investigated. No effect was observed when the system was in contact with olfactory receptor I7 in membrane fraction used for control measurements. All these results demonstrate that rhodopsin can be immobilized efficiently, specifically, quantitatively and stably on gold electrode through the self-assembled multilayer.
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Affiliation(s)
- Yanxia Hou
- Centre de Génie Electrique de Lyon (CEGELY), Ecole Centrale de Lyon, B.P.163, 69134 Ecully Cedex, France
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31
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Lad MD, Birembaut F, Matthew JM, Frazier RA, Green RJ. The adsorbed conformation of globular proteins at the air/water interface. Phys Chem Chem Phys 2006; 8:2179-86. [PMID: 16751876 DOI: 10.1039/b515934b] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
External reflection FTIR spectroscopy and surface pressure measurements were used to compare conformational changes in the adsorbed structures of three globular proteins at the air/water interface. Of the three proteins studied, lysozyme, bovine serum albumin and beta-lactoglobulin, lysozyme was unique in its behaviour. Lysozyme adsorption was slow, taking approximately 2.5 h to reach a surface pressure plateau (from a 0.07 mM solution), and led to significant structural change. The FTIR spectra revealed that lysozyme formed a highly networked adsorbed layer of unfolded protein with high antiparallel beta-sheet content and that these changes occurred rapidly (within 10 min). This non-native secondary structure is analogous to that of a 3D heat-set protein gel, suggesting that the adsorbed protein formed a highly networked interfacial layer. Albumin and beta-lactoglobulin adsorbed rapidly (reaching a plateau within 10 min) and with little change to their native secondary structure.
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Affiliation(s)
- Mitaben D Lad
- School of Chemistry, The University of Reading, PO Box 224, Whiteknights, Reading, UK RG6 6AD
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32
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Vessely CR, Carpenter JF, Schwartz DK. Calcium-Induced Changes to the Molecular Conformation and Aggregate Structure of β-Casein at the Air−Water Interface. Biomacromolecules 2005; 6:3334-44. [PMID: 16283763 DOI: 10.1021/bm050353w] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The influence of calcium on interactions of beta-casein at the air-water interface has been studied by several techniques, including interfacial rheology, atomic force microscopy (AFM), infrared reflectance-absorbance spectroscopy (IRRAS), and zeta potential measurements. In the absence of calcium, a weak interfacial gel forms after about 2.5 h. Also in the absence of calcium, the adsorbed beta-casein film exhibits some degree of both intra- and intermolecular structural organization. For example, IRRAS spectra show a measurable amount of alpha-helix content, and AFM images indicate the presence of interfacial aggregates with a characteristic lateral length scale of 20-30 nm, which we interpret as hemimicelles. Upon the addition of calcium, particularly at Ca:beta-casein molar ratios above approximately 5:1, a stronger interfacial gel forms more quickly; for example, the interfacial shear moduli increase twice as rapidly. Also under these conditions (5:1 Ca:beta-casein ratio) there is little evidence of structural organization; i.e., the alpha-helix peaks are very weak, and AFM images show a disordered, but continuous film, without distinct hemimicelles. On the basis of these findings, we hypothesize that calcium binding destabilizes the coupled intra- and intermolecular structural organization, and that the loss of organization permits more rapid interfacial gelation. These phenomena are characteristic of the air-water interface; they are not accompanied by analogous structural changes in bulk solution.
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Affiliation(s)
- Christina R Vessely
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, USA
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33
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Clare BH, Abbott NL. Orientations of nematic liquid crystals on surfaces presenting controlled densities of peptides: amplification of protein-peptide binding events. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:6451-61. [PMID: 15982053 DOI: 10.1021/la050336s] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report a study of the orientations of nematic liquid crystals (LCs) in contact with peptide-modified, oligoethylene glycol-containing, self-assembled monolayers (SAMs). The SAMs were formed on gold films that were prepared by physical vapor deposition at an oblique angle of incidence. Two peptides were investigated: the optimized substrate for the Src protein kinase (IYGEFKKKC) and the synthetic equivalent of that peptide after kinase modification (IpYGEFKKKC). Polarization modulation-infrared reflectance absorbance spectroscopy (PM-IRRAS) was used to characterize the relative areal densities and orientations of these peptides at the interface. We conclude that the presence/absence of a phosphate group can influence the maximum packing density of immobilized peptide. We evaluated the orientations of the nematic liquid crystal 5CB in contact with these peptide-modified surfaces by using polarized microscopy. The time required for the nematic phase of 5CB to exhibit long-range orientational ordering (uniform alignment) was found to increase with increasing areal densities of immobilized peptide. We also found that the specific binding event between anti-phosphotyrosine IgG and the surface-immobilized phosphopeptide leads to an increase in the time required for the liquid crystal to achieve uniform anchoring (exceeding the experimentally accessible time scales). These results, when combined, suggest that the areal density and size of biomolecules at an interface can influence the time required for liquid crystals in contact with nanostructured surfaces to exhibit long-range orientational order. Finally, we illustrate the potential utility of this system by demonstrating that liquid crystals can be used to amplify and report protein binding events occurring on a spatially resolved peptide array.
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Affiliation(s)
- Brian H Clare
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, USA
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Du X, Miao W, Liang Y. IRRAS Studies on Chain Orientation in the Monolayers of Amino Acid Amphiphiles at the Air−Water Interface Depending on Metal Complex and Hydrogen Bond Formation with the Headgroups. J Phys Chem B 2005; 109:7428-34. [PMID: 16851851 DOI: 10.1021/jp0441700] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Monolayers of N-octadecanoyl-L-alanine at the air-water interface on pure water and metal ion containing subphases have been studied using polarized infrared reflection-absorption spectroscopy (IRRAS). The metal complex and hydrogen bond formation with the headgroups give rise to a change in chain order depending on metal ion in the subphase. On pure water and Ag(+)-/Pb(2+)-containing subphase, the antisymmetric CH(2) stretching band intensity [nu(a)(CH(2))] undergoes a slower increase than the symmetric one [nu(s)(CH(2))] below the Brewster angle, so the intensity ratios of nu(a)(CH(2))/nu(s)(CH(2)) are less than 1 in the cases of Ag(+) and Pb(2+). Beyond the Brewster angle, the nu(a)(CH(2)) band intensities are substantially reduced in comparison with the nu(s)(CH(2)) ones in the cases of pure water and Ag(+), but the nu(a)(CH(2)) bands still remain negative-oriented in the presence of Pb(2+). These unusual spectral features indicate that the alkyl chains take a preferential orientation with their C-C-C planes parallel to the water surface. The parallel packing of the alkyl chains results from the intermolecular hydrogen bonds C=O...H-N between the neighboring amide groups, strengthened by the metal complex of covalent interaction. On the Ca(2+)-/Cu(2+)-containing subphase, the corresponding polarized spectra display a usual behavior. The alkyl chains are roughly estimated to be inclined around 35-40 degrees from the surface normal on the assumption of chain segment orientation for the monolayers in the liquid-expanded phase. The chain conformation and tilt are closely related to the formation of intramolecular hydrogen bonds and the ionic interaction of the metal complex in the cases of Ca(2+) and Cu(2+).
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Affiliation(s)
- Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry (Nanjing University), Ministry of Education, and Department of Chemistry, Nanjing University, Nanjing 210093, People's Republic of China.
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35
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Saccani J, Castano S, Beaurain F, Laguerre M, Desbat B. Stabilization of phospholipid multilayers at the air-water interface by compression beyond the collapse: a BAM, PM-IRRAS, and molecular dynamics study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:9190-9197. [PMID: 15461505 DOI: 10.1021/la0489920] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Compression beyond the collapse of phospholipid monolayers on a modified Langmuir trough has revealed the formation of stable multilayers at the air-water interface. Those systems are relevant new models for studying the properties of biological membranes and for understanding the nature of interactions between membranes and peptides or proteins. The collapse of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-di[cis-9-octadecenoyl]-sn-glycero-3-[phospho-l-serine] (DOPS), 1,2-di[cis-9-octadecenoyl]-sn-glycero-3-phosphocholine (DOPC), and 1,2-di[cis-9-octadecenoyl]-sn-glycero-3-[phospho-1-rac-glycerol] (DOPG) monolayers has been investigated by isotherm measurements, Brewster angle microscopy (BAM), and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). In the cases of DMPC and DOPS, the collapse of the monolayers revealed the formation of bilayer and trilayer structures, respectively. The DMPC bilayer stability has been analyzed also by a molecular dynamics study. The collapse of the DOPC and DOPG systems shows a different behavior, and the Brewster angle microscopy reveals the formation of luminous bundles, which can be interpreted as diving multilayers in the subphase.
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Affiliation(s)
- J Saccani
- Laboratoire de Physico-Chimie Moléculaire, UMR 5803-CNRS, 351 cours de la Libération, 33405 Talence Cedex, France
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Du X, Liang Y. Detection of NH Stretching Signals from the Monolayers of Amino Acid Amphiphiles at the Air−Water Interface and Change of Hydrogen Bond Depending on Metal Ion in the Subphase: Infrared Reflection−Adsorption Spectroscopy. J Phys Chem B 2004. [DOI: 10.1021/jp037509b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry, Ministry of Education, Department of Chemistry, Nanjing University, Nanjing 210093, People's Republic of China
| | - Yingqiu Liang
- Key Laboratory of Mesoscopic Chemistry, Ministry of Education, Department of Chemistry, Nanjing University, Nanjing 210093, People's Republic of China
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