1
|
Luchini A, Tidemand FG, Araya-Secchi R, Campana M, Cárdenas M, Arleth L. Structural model of tissue factor (TF) and TF-factor VIIa complex in a lipid membrane: A combined experimental and computational study. J Colloid Interface Sci 2022; 623:294-305. [PMID: 35594588 DOI: 10.1016/j.jcis.2022.04.147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/11/2022] [Accepted: 04/25/2022] [Indexed: 10/18/2022]
Abstract
Tissue factor (TF) is a membrane protein involved in blood coagulation. TF initiates a cascade of proteolytic reactions, ultimately leading to the formation of a blood clot. The first reaction consists of the binding of the coagulation factor VII and its conversion to the activated form, FVIIa. Here, we combined experimental, i.e. quartz crystal microbalance with dissipation monitoring and neutron reflectometry, and computational, i.e. molecular dynamics (MD) simulation, methods to derive a complete structural model of TF and TF/FVIIa complex in a lipid bilayer. This model shows that the TF transmembrane domain (TMD), and the flexible linker connecting the TMD to the extracellular domain (ECD), define the location of the ECD on the membrane surface. The average orientation of the ECD relative to the bilayer surface is slightly tilted towards the lipid headgroups, a conformation that we suggest is promoted by phosphatidylserine lipids, and favours the binding of FVIIa. On the other hand, the formation of the TF/FVIIa complex induces minor changes in the TF structure, and reduces the conformational freedom of both TF and FVIIA. Altogether we describe the protein-protein and protein-lipid interactions favouring blood coagulation, but also instrumental to the development of new drugs.
Collapse
Affiliation(s)
- Alessandra Luchini
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
| | | | - Raul Araya-Secchi
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Mario Campana
- ISIS-STFC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, United Kingdom
| | - Marité Cárdenas
- Biofilms Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and Society, Malmö University, Per Albin Hanssons Väg 35, 21432 Malmö, Sweden
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| |
Collapse
|
2
|
Hall SCL, Clifton LA, Sridhar P, Hardy DJ, Wotherspoon P, Wright J, Whitehouse J, Gamage N, Laxton CS, Hatton C, Hughes GW, Jeeves M, Knowles TJ. Surface-tethered planar membranes containing the β-barrel assembly machinery: a platform for investigating bacterial outer membrane protein folding. Biophys J 2021; 120:5295-5308. [PMID: 34757080 PMCID: PMC8715194 DOI: 10.1016/j.bpj.2021.10.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 09/06/2021] [Accepted: 10/26/2021] [Indexed: 11/16/2022] Open
Abstract
The outer membrane of Gram-negative bacteria presents a robust physicochemical barrier protecting the cell from both the natural environment and acting as the first line of defense against antimicrobial materials. The proteins situated within the outer membrane are responsible for a range of biological functions including controlling influx and efflux. These outer membrane proteins (OMPs) are ultimately inserted and folded within the membrane by the β-barrel assembly machine (Bam) complex. The precise mechanism by which the Bam complex folds and inserts OMPs remains unclear. Here, we have developed a platform for investigating Bam-mediated OMP insertion. By derivatizing a gold surface with a copper-chelating self-assembled monolayer, we were able to assemble a planar system containing the complete Bam complex reconstituted within a phospholipid bilayer. Structural characterization of this interfacial protein-tethered bilayer by polarized neutron reflectometry revealed distinct regions consistent with known high-resolution models of the Bam complex. Additionally, by monitoring changes of mass associated with OMP insertion by quartz crystal microbalance with dissipation monitoring, we were able to demonstrate the functionality of this system by inserting two diverse OMPs within the membrane, pertactin, and OmpT. This platform has promising application in investigating the mechanism of Bam-mediated OMP insertion, in addition to OMP function and activity within a phospholipid bilayer environment.
Collapse
Affiliation(s)
- Stephen C L Hall
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Oxfordshire, United Kingdom
| | - Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Oxfordshire, United Kingdom
| | - Pooja Sridhar
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - David J Hardy
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Peter Wotherspoon
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Jack Wright
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - James Whitehouse
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Nadisha Gamage
- Membrane Protein Laboratory, Diamond Light Source, Harwell Science & Innovation Campus, Oxfordshire, United Kingdom
| | - Claire S Laxton
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Caitlin Hatton
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Gareth W Hughes
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Mark Jeeves
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Timothy J Knowles
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom.
| |
Collapse
|
3
|
Clifton LA, Campbell RA, Sebastiani F, Campos-Terán J, Gonzalez-Martinez JF, Björklund S, Sotres J, Cárdenas M. Design and use of model membranes to study biomolecular interactions using complementary surface-sensitive techniques. Adv Colloid Interface Sci 2020; 277:102118. [PMID: 32044469 DOI: 10.1016/j.cis.2020.102118] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/24/2020] [Accepted: 01/29/2020] [Indexed: 01/07/2023]
Abstract
Cellular membranes are complex structures and simplified analogues in the form of model membranes or biomembranes are used as platforms to understand fundamental properties of the membrane itself as well as interactions with various biomolecules such as drugs, peptides and proteins. Model membranes at the air-liquid and solid-liquid interfaces can be studied using a range of complementary surface-sensitive techniques to give a detailed picture of both the structure and physicochemical properties of the membrane and its resulting interactions. In this review, we will present the main planar model membranes used in the field to date with a focus on monolayers at the air-liquid interface, supported lipid bilayers at the solid-liquid interface and advanced membrane models such as tethered and floating membranes. We will then briefly present the principles as well as the main type of information on molecular interactions at model membranes accessible using a Langmuir trough, quartz crystal microbalance with dissipation monitoring, ellipsometry, atomic force microscopy, Brewster angle microscopy, Infrared spectroscopy, and neutron and X-ray reflectometry. A consistent example for following biomolecular interactions at model membranes is used across many of the techniques in terms of the well-studied antimicrobial peptide Melittin. The overall objective is to establish an understanding of the information accessible from each technique, their respective advantages and limitations, and their complementarity.
Collapse
Affiliation(s)
- Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 OQX, United Kingdom
| | - Richard A Campbell
- Division of Pharmacy and Optometry, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Federica Sebastiani
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - José Campos-Terán
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Unidad Cuajimalpa, Av. Vasco de Quiroga 4871, Col. Santa Fe, Delegación Cuajimalpa de Morelos, 05348, Mexico; Lund Institute of advanced Neutron and X-ray Science, Lund University, Scheelevägen 19, 223 70 Lund, Sweden
| | - Juan F Gonzalez-Martinez
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Sebastian Björklund
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Javier Sotres
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Marité Cárdenas
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden.
| |
Collapse
|
4
|
Luchini A, Tidemand FG, Johansen NT, Campana M, Sotres J, Ploug M, Cárdenas M, Arleth L. Peptide Disc Mediated Control of Membrane Protein Orientation in Supported Lipid Bilayers for Surface-Sensitive Investigations. Anal Chem 2019; 92:1081-1088. [DOI: 10.1021/acs.analchem.9b04125] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Alessandra Luchini
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | | | | | - Mario Campana
- ISIS-STFC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, United Kingdom
| | - Javier Sotres
- Biofilms Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and Society, Malmö University, Per Albin Hanssons Väg 35, 214 32 Malmö, Sweden
| | - Michael Ploug
- Biotech Research and Innovation Center, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
- Finsen Laboratory, Rigshospitalet, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Marité Cárdenas
- Biofilms Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and Society, Malmö University, Per Albin Hanssons Väg 35, 214 32 Malmö, Sweden
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| |
Collapse
|
5
|
Maric S, Lind TK, Raida MR, Bengtsson E, Fredrikson GN, Rogers S, Moulin M, Haertlein M, Forsyth VT, Wenk MR, Pomorski TG, Arnebrant T, Lund R, Cárdenas M. Time-resolved small-angle neutron scattering as a probe for the dynamics of lipid exchange between human lipoproteins and naturally derived membranes. Sci Rep 2019; 9:7591. [PMID: 31110185 PMCID: PMC6527577 DOI: 10.1038/s41598-019-43713-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/27/2019] [Indexed: 12/21/2022] Open
Abstract
Atherosclerosis is the main killer in the western world. Today’s clinical markers include the total level of cholesterol and high-/low-density lipoproteins, which often fails to accurately predict the disease. The relationship between the lipid exchange capacity and lipoprotein structure should explain the extent by which they release or accept lipid cargo and should relate to the risk for developing atherosclerosis. Here, small-angle neutron scattering and tailored deuteration have been used to follow the molecular lipid exchange between human lipoprotein particles and cellular membrane mimics made of natural, “neutron invisible” phosphatidylcholines. We show that lipid exchange occurs via two different processes that include lipid transfer via collision and upon direct particle tethering to the membrane, and that high-density lipoprotein excels at exchanging the human-like unsaturated phosphatidylcholine. By mapping the specific lipid content and level of glycation/oxidation, the mode of action of specific lipoproteins can now be deciphered. This information can prove important for the development of improved diagnostic tools and in the treatment of atherosclerosis.
Collapse
Affiliation(s)
- Selma Maric
- Dept. of Biomedical Science, Malmö University, Per Albin Hanssons väg 35, 205 02, Malmö, Sweden.
| | - Tania Kjellerup Lind
- Dept. of Biomedical Science, Malmö University, Per Albin Hanssons väg 35, 205 02, Malmö, Sweden
| | - Manfred Roman Raida
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Eva Bengtsson
- Dept. of Clinical Sciences, Lund University, Jan Waldenströms gata 35, CRC, Box 50332, 212 13, Malmö, Sweden
| | - Gunilla Nordin Fredrikson
- Dept. of Clinical Sciences, Lund University, Jan Waldenströms gata 35, CRC, Box 50332, 212 13, Malmö, Sweden
| | - Sarah Rogers
- ISIS Science and Technology Facilities Council, Harwell Science and Innovation Campus, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom
| | - Martine Moulin
- Life Science Group, Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, F-38042, Grenoble, Cedex 9, France
| | - Michael Haertlein
- Life Science Group, Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, F-38042, Grenoble, Cedex 9, France
| | - V Trevor Forsyth
- Life Science Group, Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, F-38042, Grenoble, Cedex 9, France.,Faculty of Natural Science and Institute for Science and Technology in Medicine, Keele University, Staffordshire, ST5 5BG, United Kingdom
| | - Markus R Wenk
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Thomas Günther Pomorski
- Dept. of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.,Dept. of Molecular Biochemistry, Ruhr University Bochum, Faculty of Chemistry and Biochemistry, 44780, Bochum, Germany
| | - Thomas Arnebrant
- Dept. of Biomedical Science, Malmö University, Per Albin Hanssons väg 35, 205 02, Malmö, Sweden
| | - Reidar Lund
- Dept. of Chemistry, University of Oslo, Blindern, 0315, Oslo, Norway
| | - Marité Cárdenas
- Dept. of Biomedical Science, Malmö University, Per Albin Hanssons väg 35, 205 02, Malmö, Sweden.
| |
Collapse
|
6
|
The Production of Matchout-Deuterated Cholesterol and the Study of Bilayer-Cholesterol Interactions. Sci Rep 2019; 9:5118. [PMID: 30914734 PMCID: PMC6435723 DOI: 10.1038/s41598-019-41439-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/07/2019] [Indexed: 02/04/2023] Open
Abstract
The deuteration of biomolecules provides advanced opportunities for neutron scattering studies. For low resolution studies using techniques such as small-angle neutron scattering and neutron reflection, the level of deuteration of a sample can be varied to match the scattering length density of a specific D2O/H2O solvent mixture. This can be of major value in structural studies where specific regions of a complex system can be highlighted, and others rendered invisible. This is especially useful in analyses of the structure and dynamics of membrane components. In mammalian membranes, the presence of cholesterol is crucial in modulating the properties of lipids and in their interaction with proteins. Here, a protocol is described for the production of partially deuterated cholesterol which has a neutron scattering length density that matches that of 100% D2O solvent (hereby named matchout cholesterol). The level of deuteration was determined by mass spectrometry and nuclear magnetic resonance. The cholesterol match-point was verified experimentally using small angle neutron scattering. The matchout cholesterol was used to investigate the incorporation of cholesterol in various phosphatidylcholine supported lipid bilayers by neutron reflectometry. The study included both saturated and unsaturated lipids, as well as lipids with varying chain lengths. It was found that cholesterol is distributed asymmetrically within the bilayer, positioned closer to the headgroups of the lipids than to the middle of the tail core, regardless of the phosphatidylcholine species.
Collapse
|
7
|
Hoogerheide DP, Noskov SY, Kuszak AJ, Buchanan SK, Rostovtseva TK, Nanda H. Structure of voltage-dependent anion channel-tethered bilayer lipid membranes determined using neutron reflectivity. Acta Crystallogr D Struct Biol 2018; 74:1219-1232. [PMID: 30605136 PMCID: PMC6317592 DOI: 10.1107/s2059798318011749] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 08/20/2018] [Indexed: 01/05/2023] Open
Abstract
Neutron reflectivity (NR) has emerged as a powerful technique to study the structure and behavior of membrane proteins at planar lipid interfaces. Integral membrane proteins (IMPs) remain a significant challenge for NR owing to the difficulty of forming complete bilayers with sufficient protein density for scattering techniques. One strategy to achieve high protein density on a solid substrate is the capture of detergent-stabilized, affinity-tagged IMPs on a nitrilotriacetic acid (NTA)-functionalized self-assembled monolayer (SAM), followed by reconstitution into the lipids of interest. Such protein-tethered bilayer lipid membranes (ptBLMs) have the notable advantage of a uniform IMP orientation on the substrate. Here, NR is used to provide a structural characterization of the ptBLM process from formation of the SAM to capture of the detergent-stabilized IMP and lipid reconstitution. The mitochondrial outer-membrane voltage-dependent anion channel (VDAC), which controls the exchange of bioenergetic metabolites between mitochondria and the cytosol, was used as a model β-barrel IMP. Molecular dynamics simulations were used for comparison with the experimental results and to inform the parameters of the physical models describing the NR data. The detailed structure of the SAM is shown to depend on the density of the NTA chelating groups. The relative content of detergent and protein in surface-immobilized, detergent-stabilized VDAC is measured, while the reconstituted lipid bilayer is shown to be complete to within a few percent, using the known atomic structure of VDAC. Finally, excess lipid above the reconstituted bilayer, which is of consequence for more indirect structural and functional studies, is shown to be present.
Collapse
Affiliation(s)
- David P. Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20878, USA
| | - Sergei Yu. Noskov
- Centre for Molecular Simulations and Department of Biological Sciences, University of Calgary, Calgary T2N 1N4, Canada
| | - Adam J. Kuszak
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Susan K. Buchanan
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tatiana K. Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hirsh Nanda
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20878, USA
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| |
Collapse
|
8
|
Browning KL, Lind TK, Maric S, Malekkhaiat-Häffner S, Fredrikson GN, Bengtsson E, Malmsten M, Cárdenas M. Human Lipoproteins at Model Cell Membranes: Effect of Lipoprotein Class on Lipid Exchange. Sci Rep 2017; 7:7478. [PMID: 28785025 PMCID: PMC5547137 DOI: 10.1038/s41598-017-07505-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/29/2017] [Indexed: 01/19/2023] Open
Abstract
High and low density lipoproteins (HDL and LDL) are thought to play vital roles in the onset and development of atherosclerosis; the biggest killer in the western world. Key issues of initial lipoprotein (LP) interactions at cellular membranes need to be addressed including LP deposition and lipid exchange. Here we present a protocol for monitoring the in situ kinetics of lipoprotein deposition and lipid exchange/removal at model cellular membranes using the non-invasive, surface sensitive methods of neutron reflection and quartz crystal microbalance with dissipation. For neutron reflection, lipid exchange and lipid removal can be distinguished thanks to the combined use of hydrogenated and tail-deuterated lipids. Both HDL and LDL remove lipids from the bilayer and deposit hydrogenated material into the lipid bilayer, however, the extent of removal and exchange depends on LP type. These results support the notion of HDL acting as the ‘good’ cholesterol, removing lipid material from lipid-loaded cells, whereas LDL acts as the ‘bad’ cholesterol, depositing lipid material into the vascular wall.
Collapse
Affiliation(s)
- K L Browning
- Department of Pharmacy, Uppsala University, Uppsala, Sweden
| | - T K Lind
- Department of Biomedical Sciences and Biofilms, Malmö University, Malmö, Sweden
| | - S Maric
- Department of Biomedical Sciences and Biofilms, Malmö University, Malmö, Sweden
| | | | - G N Fredrikson
- Department of Clinical Sciences, Malmö, Lund University, Malmö, Sweden
| | - E Bengtsson
- Department of Clinical Sciences, Malmö, Lund University, Malmö, Sweden
| | - M Malmsten
- Department of Pharmacy, Uppsala University, Uppsala, Sweden. .,Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
| | - M Cárdenas
- Department of Biomedical Sciences and Biofilms, Malmö University, Malmö, Sweden.
| |
Collapse
|
9
|
Narayanan T, Wacklin H, Konovalov O, Lund R. Recent applications of synchrotron radiation and neutrons in the study of soft matter. CRYSTALLOGR REV 2017. [DOI: 10.1080/0889311x.2016.1277212] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | - Hanna Wacklin
- European Spallation Source ERIC, Lund, Sweden
- Physical Chemistry, Lund University, Lund, Sweden
| | | | - Reidar Lund
- Department of Chemistry, University of Oslo, Blindern, Oslo, Norway
| |
Collapse
|
10
|
Biological Structures. NEUTRON SCATTERING - APPLICATIONS IN BIOLOGY, CHEMISTRY, AND MATERIALS SCIENCE 2017. [DOI: 10.1016/b978-0-12-805324-9.00001-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
11
|
Barker RD, McKinley LE, Titmuss S. Neutron Reflectivity as a Tool for Physics-Based Studies of Model Bacterial Membranes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 915:261-82. [PMID: 27193548 DOI: 10.1007/978-3-319-32189-9_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The principles of neutron reflectivity and its application as a tool to provide structural information at the (sub-) molecular unit length scale from models for bacterial membranes are described. The model membranes can take the form of a monolayer for a single leaflet spread at the air/water interface, or bilayers of increasing complexity at the solid/liquid interface. Solid-supported bilayers constrain the bilayer to 2D but can be used to characterize interactions with antimicrobial peptides and benchmark high throughput lab-based techniques. Floating bilayers allow for membrane fluctuations, making the phase behaviour more representative of native membranes. Bilayers of varying levels of compositional accuracy can now be constructed, facilitating studies with aims that range from characterizing the fundamental physical interactions, through to the characterization of accurate mimetics for the inner and outer membranes of Gram-negative bacteria. Studies of the interactions of antimicrobial peptides with monolayer and bilayer models for the inner and outer membranes have revealed information about the molecular control of the outer membrane permeability, and the mode of interaction of antimicrobials with both inner and outer membranes.
Collapse
Affiliation(s)
- Robert D Barker
- Institut Laue-Langevin, 71 Avenue Des Martyrs, CS 20156, 38042, Grenoble Cedex 9, France.,School of Science and Engineering, University of Dundee, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Dundee, DD1 4HN, UK
| | - Laura E McKinley
- School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, Scotland
| | - Simon Titmuss
- School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, Scotland.
| |
Collapse
|