1
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Piccinini A, Kohlbrecher J, Moussaoui D, Winter A, Prévost S. Effect of cardiolipin on the lamellarity and elongation of liposomes hydrated in PBS. J Colloid Interface Sci 2024; 669:844-855. [PMID: 38749223 DOI: 10.1016/j.jcis.2024.04.211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/25/2024] [Accepted: 04/29/2024] [Indexed: 05/27/2024]
Abstract
Lamellarity and shape are important factors in the formation of vesicles and determine their role in biological systems and pharmaceutical applications. Cardiolipin (CL) is a major lipid in many biological membranes and exerts a great influence on their structural organization due to its particular structure and physico-chemical properties. Here, we used small-angle X-ray and neutron scattering to study the effects of CL with different acyl chain lengths and saturations (CL14:0, CL18:1, CL18:2) on vesicle morphology and lamellarity in membrane models containing mixtures of phosphatidylcholine and phosphatidylethanolamine with different acyl chain lengths and saturations (C14:0 and C 18:1). Measurements were performed in the presence of Phosphate Buffer Saline (PBS), at 37°C, to better reflect physiological conditions, which resulted in strong effects on vesicle morphology, depending on the type and amount of CL used. The presence of small quantities of CL (from 2.5%) reduced inter-membrane correlations and increased perturbation of the membrane, an effect which is enhanced in the presence of matched shorter saturated acyl chains, and mainly unilamellar vesicles (ULV) are formed. In extruded vesicles, employed for SANS experiments, flattened vesicles are observed partly due to the hypertonic effect of PBS, but also influenced by the type of CL added. Our experimental data from SAXS and SANS revealed a strong dependence on CL content in shaping the membrane microstructure, with an apparent optimum in the PC:CL mixture in terms of promoting reduced correlations, preferred curvature and elongation. However, the use of PBS caused distinct differences from previously published studies in water in terms of vesicle shape, and highlights the need to investigate vesicle formation under physiological conditions in order to be able to draw conclusions about membrane formation in biological systems.
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Affiliation(s)
- Alice Piccinini
- Institut Laue-Langevin - The European Neutron Source, 38042 Grenoble, France; School of Life Sciences, Keele University, ST55BG Staffordshire, United Kingdom; Dept. of Medical Biotechnology and Translational Medicine Università degli Studi di Milano, 20054 Milan, Italy
| | | | | | - Anja Winter
- School of Life Sciences, Keele University, ST55BG Staffordshire, United Kingdom.
| | - Sylvain Prévost
- Institut Laue-Langevin - The European Neutron Source, 38042 Grenoble, France
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2
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Caselli L, Conti L, De Santis I, Berti D. Small-angle X-ray and neutron scattering applied to lipid-based nanoparticles: Recent advancements across different length scales. Adv Colloid Interface Sci 2024; 327:103156. [PMID: 38643519 DOI: 10.1016/j.cis.2024.103156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 02/28/2024] [Accepted: 04/08/2024] [Indexed: 04/23/2024]
Abstract
Lipid-based nanoparticles (LNPs), ranging from nanovesicles to non-lamellar assemblies, have gained significant attention in recent years, as versatile carriers for delivering drugs, vaccines, and nutrients. Small-angle scattering methods, employing X-rays (SAXS) or neutrons (SANS), represent unique tools to unveil structure, dynamics, and interactions of such particles on different length scales, spanning from the nano to the molecular scale. This review explores the state-of-the-art on scattering methods applied to unveil the structure of lipid-based nanoparticles and their interactions with drugs and bioactive molecules, to inform their rational design and formulation for medical applications. We will focus on complementary information accessible with X-rays or neutrons, ranging from insights on the structure and colloidal processes at a nanoscale level (SAXS) to details on the lipid organization and molecular interactions of LNPs (SANS). In addition, we will review new opportunities offered by Time-resolved (TR)-SAXS and -SANS for the investigation of dynamic processes involving LNPs. These span from real-time monitoring of LNPs structural evolution in response to endogenous or external stimuli (TR-SANS), to the investigation of the kinetics of lipid diffusion and exchange upon interaction with biomolecules (TR-SANS). Finally, we will spotlight novel combinations of SAXS and SANS with complementary on-line techniques, recently enabled at Large Scale Facilities for X-rays and neutrons. This emerging technology enables synchronized multi-method investigation, offering exciting opportunities for the simultaneous characterization of the structure and chemical or mechanical properties of LNPs.
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Affiliation(s)
- Lucrezia Caselli
- Physical Chemistry 1, University of Lund, S-221 00 Lund, Sweden.
| | - Laura Conti
- Consorzio Sistemi a Grande Interfase, Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - Ilaria De Santis
- Department of Chemistry, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, Florence 50019, Italy
| | - Debora Berti
- Department of Chemistry, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, Florence 50019, Italy; Consorzio Sistemi a Grande Interfase, Department of Chemistry, University of Florence, Sesto Fiorentino, Italy.
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3
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Srivastava D, Patra N. Elucidating Daptomycin's Antibacterial Efficacy: Insights into the Tripartite Complex with Lipid II and Phospholipids in Bacterial Septum Membrane. J Phys Chem B 2024. [PMID: 38690887 DOI: 10.1021/acs.jpcb.4c00332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
This study elucidated the mechanism of formation of a tripartite complex containing daptomycin (Dap), lipid II, and phospholipid phosphatidylglycerol in the bacterial septum membrane, which was previously reported as the cause of the antibacterial action of Dap against gram-positive bacteria via molecular dynamics and enhanced sampling methods. Others have suggested that this transient complex ushers in the inhibition of cell wall synthesis by obstructing the downstream polymerization and cross-linking processes involving lipid II, which is absent in the presence of cardiolipin lipid in the membrane. In this work, we observed that the complex was stabilized by Ca2+-mediated electrostatic interactions between Dap and lipid head groups, hydrophobic interaction, hydrogen bonds, and salt bridges between the lipopeptide and lipids and was associated with Dap concentration-dependent membrane depolarization, thinning of the bilayer, and increased lipid tail disorder. Residues Orn6 and Kyn13, along with the DXDG motif, made simultaneous contact with constituent lipids, hence playing a crucial role in the formation of the complex. Incorporating cardiolipin into the membrane model led to its competitively displacing lipid II away from the Dap, reducing the lifetime of the complex and the nonexistence of lipid tail disorder and membrane depolarization. No evidence of water permeation inside the membrane hydrophobic interior was noted in all of the systems studied. Additionally, it was shown that using hydrophobic contacts between Dap and lipids as collective variables for enhanced sampling gave rise to a free energy barrier for the translocation of the lipopeptide. A better understanding of Dap's antibacterial mechanism, as studied through this work, will help develop lipopeptide-based antibiotics for rising Dap-resistant bacteria.
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Affiliation(s)
- Diship Srivastava
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Dhanbad 826004, India
| | - Niladri Patra
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Dhanbad 826004, India
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4
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Zhao J, Zhao L, Xu W, Lu Z, Xu S. Fabrication of High-Negatively Charged Bicelle-Mediated Supported Lipid Bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:8083-8093. [PMID: 38572682 DOI: 10.1021/acs.langmuir.4c00068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Supported lipid bilayers (SLBs), two-dimensional lipid films formed on a solid-supporting substrate, serve as models for biomembranes and exhibit remarkable potential in chemistry, biology, and medicine. However, preparing SLBs with highly negatively charged contents on the negatively charged surface by overcoming electrostatic repulsion remains a challenge. Here, a creative bicelle-mediated and divalent cation-free SLB preparation method with the assistance of phosphate-buffered saline (PBS) solution was proposed, which can form the SLBs containing 50% DOPS or 30% CL on the silica surface monitored by a quartz crystal microbalance with dissipation (QCM-D). Results of molecular dynamics (MD) simulation indicate that electrostatic repulsion can be overcome by the increased number of hydrogen bonds caused by the adsorption of dihydrogen phosphate ions onto the headgroups of lipids. In addition, the negatively charged SLB formation was identified to be a three-step kinetic process, which differs from a two-step mechanism in the case of amphoteric SLB. The extra kinetic step can be attributed to the reduction in the number of intermolecular hydrogen bonds and the ordering of water molecules in the hydration layer. This investigation resolves the challenge of fabricating SLB over negatively charged surfaces and offers a fresh perspective on the SLB assembly methodology.
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Affiliation(s)
- Junyi Zhao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Li Zhao
- School of Life Sciences, Jilin University, Changchun 130012, China
| | - Weiqing Xu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, China
| | - Zhongyuan Lu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, China
- Key Laboratory of Material Simulation Methods and Software of Ministry of Education, Changchun 130012, China
| | - Shuping Xu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
- Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun 130012, China
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, China
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5
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Gallucci N, Appavou MS, Cowieson N, D'Errico G, Di Girolamo R, Lettieri S, Sica F, Vitiello G, Paduano L. Ordered hierarchical superlattice amplifies coated-CeO 2 nanoparticles luminescence. J Colloid Interface Sci 2024; 659:926-935. [PMID: 38219311 DOI: 10.1016/j.jcis.2024.01.029] [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: 05/13/2023] [Revised: 12/30/2023] [Accepted: 01/04/2024] [Indexed: 01/16/2024]
Abstract
Achieving a controlled preparation of nanoparticle superstructures with spatially periodic arrangement, also called superlattices, is one of the most intriguing and open questions in soft matter science. The interest in such regular superlattices originates from the potentialities in tailoring the physicochemical properties of the individual constituent nanoparticles, eventually leading to emerging behaviors and/or functionalities that are not exhibited by the initial building blocks. Despite progress, it is currently difficult to obtain such ordered structures; the influence of parameters, such as size, softness, interaction potentials, and entropy, are neither fully understood yet and not sufficiently studied for 3D systems. In this work, we describe the synthesis and characterization of spatially ordered hierarchical structures of coated cerium oxide nanoparticles in water suspension prepared by a bottom-up approach. Covering the CeO2 surface with amphiphilic molecules having chains of appropriate length makes it possible to form ordered structures in which the particles occupy well-defined positions. In the present case superlattice arrangement is accompanied by an improvement in photoluminescence (PL) efficiency, as an increase in PL intensity of the superlattice structure of up to 400 % compared with that of randomly dispersed nanoparticles was observed. To the best of our knowledge, this is one of the first works in the literature in which the coexistence of 3D structures in solution, such as face-centered cubic (FCC) and Frank-Kasper (FK) phases, of semiconductor nanoparticles have been related to their optical properties.
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Affiliation(s)
- Noemi Gallucci
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy,; CSGI, Center for Colloid and Surface Science, 50019 Sesto Fiorentino, Italy
| | - Marie-Sousai Appavou
- Jülich Center for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Nathan Cowieson
- Diamond Light Source, Didcot, Oxfordshire, England, United Kingdom
| | - Gerardino D'Errico
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy,; CSGI, Center for Colloid and Surface Science, 50019 Sesto Fiorentino, Italy
| | - Rocco Di Girolamo
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
| | - Stefano Lettieri
- Department of Physics, University of Naples Federico II, Via Cupa Cintia 21, 80126 Naples, Italy
| | - Filomena Sica
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
| | - Giuseppe Vitiello
- CSGI, Center for Colloid and Surface Science, 50019 Sesto Fiorentino, Italy; Department of Chemical, Materials and Production Engineering, University of Naples Federico II, 80125 Naples, Italy
| | - Luigi Paduano
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy,; CSGI, Center for Colloid and Surface Science, 50019 Sesto Fiorentino, Italy.
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6
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Mitchison-Field LM, Belin BJ. Bacterial lipid biophysics and membrane organization. Curr Opin Microbiol 2023; 74:102315. [PMID: 37058914 PMCID: PMC10523990 DOI: 10.1016/j.mib.2023.102315] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 04/16/2023]
Abstract
The formation of lateral microdomains is emerging as a central organizing principle in bacterial membranes. These microdomains are targets of antibiotic development and have the potential to enhance natural product synthesis, but the rules governing their assembly are unclear. Previous studies have suggested that microdomain formation is promoted by lipid phase separation, particularly by cardiolipin (CL) and isoprenoid lipids, and there is strong evidence that CL biosynthesis is required for recruitment of membrane proteins to cell poles and division sites. New work demonstrates that additional bacterial lipids may mediate membrane protein localization and function, opening the field for mechanistic evaluation of lipid-driven membrane organization in vivo.
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Affiliation(s)
- Lorna My Mitchison-Field
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, USA; Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Brittany J Belin
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, USA; Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
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7
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Blake MJ, Castillo HB, Curtis AE, Calhoun TR. Facilitating flip-flop: Structural tuning of molecule-membrane interactions in living bacteria. Biophys J 2023; 122:1735-1747. [PMID: 37041744 PMCID: PMC10209030 DOI: 10.1016/j.bpj.2023.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/17/2023] [Accepted: 04/04/2023] [Indexed: 04/13/2023] Open
Abstract
The first barrier that a small molecule must overcome before trespassing into a living cell is the lipid bilayer surrounding the intracellular content. It is imperative, therefore, to understand how the structure of a small molecule influences its fate in this region. Through the use of second harmonic generation, we show how the differing degrees of ionic headgroups, conjugated system, and branched hydrocarbon tail disparities of a series of four styryl dye molecules influence the propensity to "flip-flop" or to be further organized in the outer leaflet by the membrane. We show here that initial adsorption experiments match previous studies on model systems; however, more complex dynamics are observed over time. Aside from probe molecule structure, these dynamics also vary between cell species and can deviate from trends reported based on model membranes. Specifically, we show here that the membrane composition is an important factor to consider for headgroup-mediated small-molecule dynamics. Overall, the findings presented here on how structural variability of small molecules impacts their initial adsorption and eventual destinations within membranes in the context of living cells could have practical applications in antibiotic and drug adjuvant design.
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Affiliation(s)
- Marea J Blake
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee
| | - Hannah B Castillo
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee
| | - Anna E Curtis
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee
| | - Tessa R Calhoun
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee.
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8
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Di Lorenzo F, Nicolardi S, Marchetti R, Vanacore A, Gallucci N, Duda K, Nieto Fabregat F, Nguyen HNA, Gully D, Saenz J, Giraud E, Paduano L, Molinaro A, D’Errico G, Silipo A. Expanding Knowledge of Methylotrophic Capacity: Structure and Properties of the Rough-Type Lipopolysaccharide from Methylobacterium extorquens and Its Role on Membrane Resistance to Methanol. JACS AU 2023; 3:929-942. [PMID: 37006758 PMCID: PMC10052234 DOI: 10.1021/jacsau.3c00025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/11/2023] [Accepted: 02/15/2023] [Indexed: 06/19/2023]
Abstract
The ability of Methylobacterium extorquens to grow on methanol as the sole carbon and energy source has been the object of intense research activity. Unquestionably, the bacterial cell envelope serves as a defensive barrier against such an environmental stressor, with a decisive role played by the membrane lipidome, which is crucial for stress resistance. However, the chemistry and the function of the main constituent of the M. extorquens outer membrane, the lipopolysaccharide (LPS), is still undefined. Here, we show that M. extorquens produces a rough-type LPS with an uncommon, non-phosphorylated, and extensively O-methylated core oligosaccharide, densely substituted with negatively charged residues in the inner region, including novel monosaccharide derivatives such as O-methylated Kdo/Ko units. Lipid A is composed of a non-phosphorylated trisaccharide backbone with a distinctive, low acylation pattern; indeed, the sugar skeleton was decorated with three acyl moieties and a secondary very long chain fatty acid, in turn substituted by a 3-O-acetyl-butyrate residue. Spectroscopic, conformational, and biophysical analyses on M. extorquens LPS highlighted how structural and tridimensional features impact the molecular organization of the outer membrane. Furthermore, these chemical features also impacted and improved membrane resistance in the presence of methanol, thus regulating membrane ordering and dynamics.
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Affiliation(s)
- Flaviana Di Lorenzo
- Department
of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
| | - Simone Nicolardi
- Center
for Proteomics and Metabolomics, Leiden
University Medical Center, Leiden 2333 ZA, The Netherlands
| | - Roberta Marchetti
- Department
of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
| | - Adele Vanacore
- Department
of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
| | - Noemi Gallucci
- Department
of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
- CSGI, Consorzio
Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase, Via della Lastruccia 3, Sesto Fiorentino, Florence 50019, Italy
| | - Katarzyna Duda
- Research
Center Borstel Leibniz Lung Center, Parkallee 4a, 23845 Borstel, Germany
| | - Ferran Nieto Fabregat
- Department
of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
| | - Ha Ngoc Anh Nguyen
- B-CUBE
Center for Molecular Bioengineering, Technische
Universität Dresden, Tatzberg 41, 01307 Dresden, Germany
| | - Djamel Gully
- IRD,
Laboratoire des Symbioses Tropicales et Méditerranéennes
(LSTM) UMR IRD/SupAgro/INRA/UM2/CIRAD, TA-A82/J, Campus de Baillarguet, 34398 Montpellier Cedex 5, France
| | - James Saenz
- B-CUBE
Center for Molecular Bioengineering, Technische
Universität Dresden, Tatzberg 41, 01307 Dresden, Germany
| | - Eric Giraud
- IRD,
Laboratoire des Symbioses Tropicales et Méditerranéennes
(LSTM) UMR IRD/SupAgro/INRA/UM2/CIRAD, TA-A82/J, Campus de Baillarguet, 34398 Montpellier Cedex 5, France
| | - Luigi Paduano
- Department
of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
- CSGI, Consorzio
Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase, Via della Lastruccia 3, Sesto Fiorentino, Florence 50019, Italy
| | - Antonio Molinaro
- Department
of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
| | - Gerardino D’Errico
- Department
of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
- CSGI, Consorzio
Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase, Via della Lastruccia 3, Sesto Fiorentino, Florence 50019, Italy
| | - Alba Silipo
- Department
of Chemical Sciences and Task Force for Microbiome Studies, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
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9
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Heller WT. Small-Angle Neutron Scattering for Studying Lipid Bilayer Membranes. Biomolecules 2022; 12:1591. [PMID: 36358941 PMCID: PMC9687511 DOI: 10.3390/biom12111591] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/18/2022] [Accepted: 10/26/2022] [Indexed: 09/23/2023] Open
Abstract
Small-angle neutron scattering (SANS) is a powerful tool for studying biological membranes and model lipid bilayer membranes. The length scales probed by SANS, being from 1 nm to over 100 nm, are well-matched to the relevant length scales of the bilayer, particularly when it is in the form of a vesicle. However, it is the ability of SANS to differentiate between isotopes of hydrogen as well as the availability of deuterium labeled lipids that truly enable SANS to reveal details of membranes that are not accessible with the use of other techniques, such as small-angle X-ray scattering. In this work, an overview of the use of SANS for studying unilamellar lipid bilayer vesicles is presented. The technique is briefly presented, and the power of selective deuteration and contrast variation methods is discussed. Approaches to modeling SANS data from unilamellar lipid bilayer vesicles are presented. Finally, recent examples are discussed. While the emphasis is on studies of unilamellar vesicles, examples of the use of SANS to study intact cells are also presented.
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Affiliation(s)
- William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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10
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Li S, Ren R, Lyu L, Song J, Wang Y, Lin TW, Brun AL, Hsu HY, Shen HH. Solid and Liquid Surface-Supported Bacterial Membrane Mimetics as a Platform for the Functional and Structural Studies of Antimicrobials. MEMBRANES 2022; 12:membranes12100906. [PMID: 36295664 PMCID: PMC9609327 DOI: 10.3390/membranes12100906] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/05/2022] [Accepted: 09/13/2022] [Indexed: 06/02/2023]
Abstract
Increasing antibiotic resistance has provoked the urgent need to investigate the interactions of antimicrobials with bacterial membranes. The reasons for emerging antibiotic resistance and innovations in novel therapeutic approaches are highly relevant to the mechanistic interactions between antibiotics and membranes. Due to the dynamic nature, complex compositions, and small sizes of native bacterial membranes, bacterial membrane mimetics have been developed to allow for the in vitro examination of structures, properties, dynamics, and interactions. In this review, three types of model membranes are discussed: monolayers, supported lipid bilayers, and supported asymmetric bilayers; this review highlights their advantages and constraints. From monolayers to asymmetric bilayers, biomimetic bacterial membranes replicate various properties of real bacterial membranes. The typical synthetic methods for fabricating each model membrane are introduced. Depending on the properties of lipids and their biological relevance, various lipid compositions have been used to mimic bacterial membranes. For example, mixtures of phosphatidylethanolamines (PE), phosphatidylglycerols (PG), and cardiolipins (CL) at various molar ratios have been used, approaching actual lipid compositions of Gram-positive bacterial membranes and inner membranes of Gram-negative bacteria. Asymmetric lipid bilayers can be fabricated on solid supports to emulate Gram-negative bacterial outer membranes. To probe the properties of the model bacterial membranes and interactions with antimicrobials, three common characterization techniques, including quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance (SPR), and neutron reflectometry (NR) are detailed in this review article. Finally, we provide examples showing that the combination of bacterial membrane models and characterization techniques is capable of providing crucial information in the design of new antimicrobials that combat bacterial resistance.
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Affiliation(s)
- Shiqi Li
- Department of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Ruohua Ren
- Department of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Letian Lyu
- Department of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Jiangning Song
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Yajun Wang
- College of Chemistry & Materials Engineering, Wenzhou University, Wenzhou 325035, China
| | - Tsung-Wu Lin
- Department of Chemistry, Tunghai University, No. 1727, Sec. 4, Taiwan Boulevard, Xitun District, Taichung 40704, Taiwan
| | - Anton Le Brun
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Hsien-Yi Hsu
- Department of Materials Science and Engineering, School of Energy and Environment, City University of Hong Kong, Kowloon Tong, Hong Kong, China
| | - Hsin-Hui Shen
- Department of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
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11
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Penicillin-binding proteins (PBPs) determine antibiotic action in Langmuir monolayers as nanoarchitectonics mimetic membranes of methicillin-resistant Staphylococcus aureus. Colloids Surf B Biointerfaces 2022; 214:112447. [PMID: 35334310 DOI: 10.1016/j.colsurfb.2022.112447] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/02/2022] [Accepted: 03/03/2022] [Indexed: 01/15/2023]
Abstract
The membrane of methicillin-resistant Staphylococcus aureus (MRSA) contains penicillin-binding proteins (PBPs) in the phospholipidic bilayer, with the protein PBP2a being linked with the resistance mechanism. In this work we confirm the role of PBP2a with molecular-level information obtained with Langmuir monolayers as cell membrane models. The MRSA cell membrane was mimicked with a mixed monolayer of dipalmitoyl phosphatidyl glycerol (DPPG) and cardiolipin (CL), also incorporating PBP2a. The surface pressure-area isotherms and the Brewster angle microscopy (BAM) images for these mixed monolayers were significantly affected by the antibiotic meropenem, which is PBP2a inhibitor. The meropenem effects were associated with the presence of PBP2a, as they were absent in the Langmuir monolayers without PBP2a. The relevance of PBP2a was confirmed with results where the antibiotic methicillin, known to be unsuitable to kill MRSA, had the same effects on mixed DPPG/CL and DPPG/CL-PBP2a monolayers since it prevented PBP2a from incorporating in the monolayer. The biological implication of the findings presented here is that a successful antibiotic against MRSA should be able to interact with PBP2a, but in the membrane.
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Hsieh MK, Yu Y, Klauda JB. All-Atom Modeling of Complex Cellular Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:3-17. [PMID: 34962814 DOI: 10.1021/acs.langmuir.1c02084] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cell membranes are composed of a variety of lipids and proteins where they interact with each other to fulfill their roles. The first step in modeling these interactions in molecular simulations is to have reliable mimetics of the membrane's lipid environment. This Feature Article presents our recent efforts to model complex cellular membranes using all-atom force fields. A short review of the CHARMM36 (C36) lipid force field and its recent update to incorporate the long-range dispersion is presented. Key examples of model membranes mimicking various species and organelles are given. These include single-celled organisms such as bacteria (E. coli., chlamydia, and P. aeruginosa) and yeast (plasma membrane, endoplasmic reticulum, and trans-Golgi network) and more advanced ones such as plants (soybean and Arabidopsis thaliana) and mammals (ocular lens, stratum corneum, and peripheral nerve myelin). Leaflet asymmetry in composition has also been applied to some of these models. With the increased lipid diversity in the C36 lipid FF, these complex models can better reflect the structural, mechanical, and dynamic properties of realistic membranes and open an opportunity to study biological processes involving other molecules.
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Mach M, Kowalska M, Olechowska K, Płachta Ł, Wydro P. The studies on the membrane activity of triester of phosphatidylcholine in artificial membrane systems. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183711. [PMID: 34343534 DOI: 10.1016/j.bbamem.2021.183711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 11/28/2022]
Abstract
Due to the increasing number of infections together with the appearance of bacteria exhibiting multi-drug resistance, new antibiotics are being sought. In this context the interest of the cationic lipoids increases because of their amphiphilic structure and positive charge that can stimulates the antibacterial action of these compounds. Thus, in this work we have performed the studies on the effect of one selected triesters of phosphatidylcholine, namely 1,2-dipalmitoyl-sn-glycero-3-ethylphosphocholine (EDPPC), on the model lipid membranes. The investigations included the analysis of the impact of EDPPC on multicomponent monolayers and bilayers consisting of the lipids naturally occurring in bacterial membranes (phosphatidylethanolamines (PE), phosphatidylglycerols (PG) and cardiolipin (CL)), mixed in proportions reflecting the lipid composition of these biomembranes. In the study, the Langmuir monolayers (registered on water and PBS buffer) and liposomes as model bacterial biomembranes were applied. The obtained results demonstrate that the presence of cationic lipoid in PE/PG and PE/PG/CL systems significantly modifies their properties and molecular organization. The incorporation of EDPPC into model bacterial membranes primarily impact on the intermolecular interactions. It was shown that the strength of the interaction between the cationic lipid and the components of the model membranes depends both on the composition of the membrane as well as on the type of subphase. Furthermore, the investigated cationic lipoid leads to the decrease of the ordering of acyl chains and thus to the increase of fluidity of membranes. The obtained results allow one to propose that EDPPC may behave as antibiotic active at the level of membrane.
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Affiliation(s)
- Marzena Mach
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland.
| | - Magdalena Kowalska
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Karolina Olechowska
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Łukasz Płachta
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Paweł Wydro
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland.
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