1
|
Schneck E, Reed J, Seki T, Nagata Y, Kanduč M. Experimental and simulation-based characterization of surfactant adsorption layers at fluid interfaces. Adv Colloid Interface Sci 2024; 331:103237. [PMID: 38959812 DOI: 10.1016/j.cis.2024.103237] [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: 11/07/2023] [Revised: 06/10/2024] [Accepted: 06/13/2024] [Indexed: 07/05/2024]
Abstract
Adsorption of surfactants to fluid interfaces occurs in numerous technological and daily-life contexts. The coverage at the interface and other properties of the formed adsorption layers determine the performance of a surfactant with regard to the desired application. Given the importance of these applications, there is a great demand for the comprehensive characterization and understanding of surfactant adsorption layers. In this review, we provide an overview of suitable experimental and simulation-based techniques and review the literature in which they were used for the investigation of surfactant adsorption layers. We come to the conclusion that, while these techniques have been successfully applied to investigate Langmuir monolayers of water-insoluble surfactants, their application to the study of Gibbs adsorption layers of water-soluble surfactants has not been fully exploited. Finally, we emphasize the great potential of these methods in providing a deeper understanding of the behavior of soluble surfactants at interfaces, which is crucial for optimizing their performance in various applications.
Collapse
Affiliation(s)
- Emanuel Schneck
- Department of Physics, Technische Universität Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Joshua Reed
- Department of Physics, Technische Universität Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany
| | - Takakazu Seki
- Graduate School of Science and Technology, Hirosaki University, Hirosaki, 036-8561 Aomori, Japan
| | - Yuki Nagata
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Matej Kanduč
- Department of Theoretical Physics, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
| |
Collapse
|
2
|
Shen C, Zhang H, Ocko BM. Reconstructing the reflectivity of liquid surfaces from grazing incidence X-ray off-specular scattering data. J Appl Crystallogr 2024; 57:714-727. [PMID: 38846761 PMCID: PMC11151673 DOI: 10.1107/s1600576724002887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Accepted: 04/01/2024] [Indexed: 06/09/2024] Open
Abstract
The capillary wave model of a liquid surface predicts both the X-ray specular reflection and the diffuse scattering around it. A quantitative method is presented to obtain the X-ray reflectivity (XRR) from a liquid surface through the diffuse scattering data around the specular reflection measured using a grazing incidence X-ray off-specular scattering (GIXOS) geometry at a fixed horizontal offset angle with respect to the plane of incidence. With this approach the entire Qz -dependent reflectivity profile can be obtained at a single, fixed incident angle. This permits a much faster acquisition of the profile than with conventional reflectometry, where the incident angle must be scanned point by point to obtain a Qz -dependent profile. The XRR derived from the GIXOS-measured diffuse scattering, referred to in this paper as pseudo-reflectivity, provides a larger Qz range compared with the reflectivity measured by conventional reflectometry. Transforming the GIXOS-measured diffuse scattering profile to pseudo-XRR opens up the GIXOS method to widely available specular XRR analysis software tools. Here the GIXOS-derived pseudo-XRR is compared with the XRR measured by specular reflectometry from two simple vapor-liquid interfaces at different surface tension, and from a hexadecyltri-methyl-ammonium bromide monolayer on a water surface. For the simple liquids, excellent agreement (beyond 11 orders of magnitude in signal) is found between the two methods, supporting the approach of using GIXOS-measured diffuse scattering to derive reflectivities. Pseudo-XRR obtained at different horizontal offset angles with respect to the plane of incidence yields indistinguishable results, and this supports the robustness of the GIXOS-XRR approach. The pseudo-XRR method can be extended to soft thin films on a liquid surface, and criteria are established for the applicability of the approach.
Collapse
Affiliation(s)
- Chen Shen
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Honghu Zhang
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Benjamin M. Ocko
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| |
Collapse
|
3
|
Grava M, Ibrahim M, Sudarsan A, Pusterla J, Philipp J, Rädler JO, Schwierz N, Schneck E. Combining molecular dynamics simulations and x-ray scattering techniques for the accurate treatment of protonation degree and packing of ionizable lipids in monolayers. J Chem Phys 2023; 159:154706. [PMID: 37861119 DOI: 10.1063/5.0172552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023] Open
Abstract
The pH-dependent change in protonation of ionizable lipids is crucial for the success of lipid-based nanoparticles as mRNA delivery systems. Despite their widespread application in vaccines, the structural changes upon acidification are not well understood. Molecular dynamics simulations support structure prediction but require an a priori knowledge of the lipid packing and protonation degree. The presetting of the protonation degree is a challenging task in the case of ionizable lipids since it depends on pH and on the local lipid environment and often lacks experimental validation. Here, we introduce a methodology of combining all-atom molecular dynamics simulations with experimental total-reflection x-ray fluorescence and scattering measurements for the ionizable lipid Dlin-MC3-DMA (MC3) in POPC monolayers. This joint approach allows us to simultaneously determine the lipid packing and the protonation degree of MC3. The consistent parameterization is expected to be useful for further predictive modeling of the action of MC3-based lipid nanoparticles.
Collapse
Affiliation(s)
- Miriam Grava
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Mohd Ibrahim
- Institute of Physics, University of Augsburg, Augsburg, Germany
| | - Akhil Sudarsan
- Institute of Physics, University of Augsburg, Augsburg, Germany
| | - Julio Pusterla
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Julian Philipp
- Fakultät für Physik, Ludwig-Maximilians-Universität München (LMU), München, Germany
| | - Joachim O Rädler
- Fakultät für Physik, Ludwig-Maximilians-Universität München (LMU), München, Germany
| | - Nadine Schwierz
- Institute of Physics, University of Augsburg, Augsburg, Germany
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
| |
Collapse
|
4
|
Castelletto V, Seitsonen J, Hamley IW. Effect of Glycosylation on Self-Assembly of Lipid A Lipopolysaccharides in Aqueous Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37289534 DOI: 10.1021/acs.langmuir.3c00828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lipopolysaccharides (LPSs) based on lipid A produced by bacteria are of interest due to their bioactivity in stimulating immune responses, as are simpler synthetic components or analogues. Here, the self-assembly in water of two monodisperse lipid A derivatives based on simplified bacterial LPS structures is examined and compared to that of a native Escherichia coli LPS using small-angle X-ray scattering and cryogenic transmission electron microscopy. The critical aggregation concentration is obtained from fluorescence probe experiments, and conformation is probed using circular dichroism spectroscopy. The E. coli LPS is found to form wormlike micelles, whereas the synthetic analogues bearing six lipid chains and with four or two saccharide head groups (Kdo2-lipid A and monophosphoryl lipid A) self-assemble into nanosheets or vesicles, respectively. These observations are rationalized by considering the surfactant packing parameter.
Collapse
Affiliation(s)
- Valeria Castelletto
- School of Chemistry, Food Biosciences and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K
| | - Jani Seitsonen
- Nanomicroscopy Center, Aalto University, Puumiehenkuja 2, Espoo FIN-02150, Finland
| | - Ian W Hamley
- School of Chemistry, Food Biosciences and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K
| |
Collapse
|
5
|
Laffargue T, Moulis C, Remaud-Simeon M. Phosphorylated polysaccharides: Applications, natural abundance, and new-to-nature structures generated by chemical and enzymatic functionalization. Biotechnol Adv 2023; 65:108140. [PMID: 36958536 DOI: 10.1016/j.biotechadv.2023.108140] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/14/2023] [Accepted: 03/18/2023] [Indexed: 03/25/2023]
Abstract
Polysaccharides are foreseen as serious candidates for the future generation of polymers, as they are biosourced and biodegradable materials. Their functionalisation is an attractive way to modify their properties, thereby increasing their range of applications. Introduction of phosphate groups in polysaccharide chains for the stimulation of the immune system was first described in the nineteen seventies. Since then, the use of phosphorylated polysaccharides has been proposed in various domains, such as healthcare, water treatment, cosmetic, biomaterials, etc. These alternative usages capitalize on newly acquired physico-chemical or biological properties, leading to materials as diverse as flame-resistant agents or drug delivery systems. Phosphorylated polysaccharides are found in Nature and need to be extracted to assess their biological potential. However, they are not abundant, often present complex backbones hard to characterize, and most of them have a low phosphate content. These drawbacks have pushed forward the development of chemical phosphorylation employing a wide variety of phosphorylating agents to obtain polysaccharides with a large range of phosphate content. Chemical phosphorylation requires the use of harsh conditions and toxic, petroleum-based solvents, which hinders their exploitation in the food and health industry. Over the last 20 years, although enzymes are regiospecific catalysts that work in aqueous and mild conditions, enzymatic phosphorylation has been little investigated. To date, only three families of enzymes have been used for the in vitro phosphorylation of polysaccharides. Considering the number of unresolved metabolic pathways leading to phosphorylated polysaccharides, the huge diversity of kinase sequences, and the recent progress in protein engineering one can envision native and engineered kinases as promising tools for polysaccharide phosphorylation.
Collapse
Affiliation(s)
- Thibaud Laffargue
- Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRAE, INSA, 135, Avenue de Rangueil, CEDEX 04, F-31077 Toulouse, France
| | - Claire Moulis
- Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRAE, INSA, 135, Avenue de Rangueil, CEDEX 04, F-31077 Toulouse, France
| | - Magali Remaud-Simeon
- Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRAE, INSA, 135, Avenue de Rangueil, CEDEX 04, F-31077 Toulouse, France.
| |
Collapse
|
6
|
Newman KE, Khalid S. Conformational dynamics and putative substrate extrusion pathways of the N-glycosylated outer membrane factor CmeC from Campylobacter jejuni. PLoS Comput Biol 2023; 19:e1010841. [PMID: 36638139 PMCID: PMC9879487 DOI: 10.1371/journal.pcbi.1010841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 01/26/2023] [Accepted: 12/26/2022] [Indexed: 01/14/2023] Open
Abstract
The outer membrane factor CmeC of the efflux machinery CmeABC plays an important role in conferring antibiotic and bile resistance to Campylobacter jejuni. Curiously, the protein is N-glycosylated, with the glycans playing a key role in the effective function of this system. In this work we have employed atomistic equilibrium molecular dynamics simulations of CmeC in a representative model of the C. jejuni outer membrane to characterise the dynamics of the protein and its associated glycans. We show that the glycans are more conformationally labile than had previously been thought. The extracellular loops of CmeC visit the open and closed states freely suggesting the absence of a gating mechanism on this side, while the narrow periplasmic entrance remains tightly closed, regulated via coordination to solvated cations. We identify several cation binding sites on the interior surface of the protein. Additionally, we used steered molecular dynamics simulations to elucidate translocation pathways for a bile acid and a macrolide antibiotic. These, and additional equilibrium simulations suggest that the anionic bile acid utilises multivalent cations to climb the ladder of acidic residues that line the interior surface of the protein.
Collapse
Affiliation(s)
- Kahlan E. Newman
- School of Chemistry, University of Southampton, Southampton, United Kingdom
| | - Syma Khalid
- School of Chemistry, University of Southampton, Southampton, United Kingdom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail:
| |
Collapse
|
7
|
Pusterla J, Scoppola E, Appel C, Mukhina T, Shen C, Brezesinski G, Schneck E. Characterization of lipid bilayers adsorbed to functionalized air/water interfaces. NANOSCALE 2022; 14:15048-15059. [PMID: 36200471 DOI: 10.1039/d2nr03334h] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Lipid bilayers immobilized in planar geometries, such as solid-supported or "floating" bilayers, have enabled detailed studies of biological membranes with numerous experimental techniques, notably X-ray and neutron reflectometry. However, the presence of a solid support also has disadvantages as it complicates the use of spectroscopic techniques as well as surface rheological measurements that would require surface deformations. Here, in order to overcome these limitations, we investigate lipid bilayers adsorbed to inherently soft and experimentally well accessible air/water interfaces that are functionalized with Langmuir monolayers of amphiphiles. The bilayers are characterized with ellipsometry, X-ray scattering, and X-ray fluorescence. Grazing-incidence X-ray diffraction reveals that lipid bilayers in a chain-ordered state can have significantly different structural features than regular Langmuir monolayers of the same composition. Our results suggest that bilayers at air/water interfaces may be well suited for fundamental studies in the field of membrane biophysics.
Collapse
Affiliation(s)
- Julio Pusterla
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Ernesto Scoppola
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Christian Appel
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Tetiana Mukhina
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Chen Shen
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Gerald Brezesinski
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Paracini N, Schneck E, Imberty A, Micciulla S. Lipopolysaccharides at Solid and Liquid Interfaces: Models for Biophysical Studies of the Gram-negative Bacterial Outer Membrane. Adv Colloid Interface Sci 2022; 301:102603. [PMID: 35093846 DOI: 10.1016/j.cis.2022.102603] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 11/18/2022]
Abstract
Lipopolysaccharides (LPSs) are a constitutive element of the cell envelope of Gram-negative bacteria, representing the main lipid in the external leaflet of their outer membrane (OM) lipid bilayer. These unique surface-exposed glycolipids play a central role in the interactions of Gram-negative organisms with their surrounding environment and represent a key element for protection against antimicrobials and the development of antibiotic resistance. The biophysical investigation of a wide range of different types of in vitro model membranes containing reconstituted LPS has revealed functional and structural properties of these peculiar membrane lipids, providing molecular-level details of their interaction with antimicrobial compounds. LPS assemblies reconstituted at interfaces represent a versatile tool to study the properties of the Gram-negative OM by exploiting several surface-sensitive techniques, in particular X-ray and neutron scattering, which can probe the structure of thin films with sub-nanometer resolution. This review provides an overview of different approaches employed to investigate structural and biophysical properties of LPS, focusing on studies on Langmuir monolayers of LPS at the air/liquid interface and a range of supported LPS-containing model membranes reconstituted at solid/liquid interfaces.
Collapse
Affiliation(s)
| | - Emanuel Schneck
- Physics Departent, Technische Universität Darmstadt, Darmstadt, Germany
| | - Anne Imberty
- Université Grenoble Alpes, CNRS, CERMAV, Grenoble, France
| | | |
Collapse
|
10
|
Kanduč M, Schneck E, Stubenrauch C. Intersurfactant H-bonds between head groups of n-dodecyl-β-d-maltoside at the air-water interface. J Colloid Interface Sci 2021; 586:588-595. [DOI: 10.1016/j.jcis.2020.10.125] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 10/23/2022]
|
11
|
Thoma J, Abuillan W, Furikado I, Habe T, Yamamoto A, Gierlich S, Kaufmann S, Brandenburg K, Gutsmann T, Konovalov O, Inoue S, Tanaka M. Specific localisation of ions in bacterial membranes unravels physical mechanism of effective bacteria killing by sanitiser. Sci Rep 2020; 10:12302. [PMID: 32704045 PMCID: PMC7378190 DOI: 10.1038/s41598-020-69064-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/06/2020] [Indexed: 12/02/2022] Open
Abstract
Antimicrobial resistance is a major threat to public health. Although many commercial sanitisers contain a combination of cationic surfactants and aromatic alcohols, the physical mechanisms where these two substances bind to or how they disturb bacterial membranes are still largely unknown. In this study, we designed a well-defined model of Gram-negative bacteria surfaces based on the monolayer of lipopolysaccharides with uniform saccharide head groups. Since commonly used X-ray reflectivity is sensitive to changes in the thickness, roughness and electron density but is not sensitive to elements, we employed grazing incidence X-ray fluorescence. In the absence of Ca2+, cationic surfactants can penetrate into the membrane core with no extra support by disturbing the layer of K+ coupled to negatively charged saccharide head group at z = 17 Å from the air/chain interface. On the other hand, Ca2+ confined at z = 19 Å crosslink charged saccharides and prevent the incorporation of cationic surfactants. We found that the addition of nonlethal aromatic alcohols facilitate the incorporation of cationic surfactants by the significant roughening of the chain/saccharide interface. Combination of precise localisation of ions and molecular-level structural analysis quantitatively demonstrated the synegtestic interplay of ingredients to achieve a high antibacterial activity.
Collapse
Affiliation(s)
- Judith Thoma
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany
| | - Wasim Abuillan
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany.
| | - Ippei Furikado
- Analytical Science Research Laboratories, Kao Corporation, 1334 Minato, Wakayama, Wakayama Prefecture, 640-8580, Japan
| | - Taichi Habe
- Analytical Science Research Laboratories, Kao Corporation, 1334 Minato, Wakayama, Wakayama Prefecture, 640-8580, Japan
| | - Akihisa Yamamoto
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto, 606-8501, Japan
| | - Simone Gierlich
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany
| | - Stefan Kaufmann
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany
| | - Klaus Brandenburg
- Research Center Borstel, Leibniz Lung Center, 23845, Borstel, Germany.,Brandenburg Antiinfektiva GmbH, 23845, Borstel, Germany
| | - Thomas Gutsmann
- Research Center Borstel, Leibniz Lung Center, 23845, Borstel, Germany
| | - Oleg Konovalov
- European Synchrotron Radiation Facility (ESRF), 38043, Grenoble, France
| | - Shigeto Inoue
- Analytical Science Research Laboratories, Kao Corporation, 1334 Minato, Wakayama, Wakayama Prefecture, 640-8580, Japan.
| | - Motomu Tanaka
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany. .,Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto, 606-8501, Japan.
| |
Collapse
|
12
|
Redeker C, Briscoe WH. Interactions between Mutant Bacterial Lipopolysaccharide (LPS-Ra) Surface Layers: Surface Vesicles, Membrane Fusion, and Effect of Ca 2+and Temperature. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15739-15750. [PMID: 31604373 DOI: 10.1021/acs.langmuir.9b02609] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lipopolysaccharides (LPS) are a major component of the protective outer membrane of Gram-negative bacteria. Understanding how the solution conditions may affect LPS-containing membranes is important to optimizing the design of antibacterial agents (ABAs) which exploit electrostatic and hydrophobic interactions to disrupt the bacteria membrane. Here, interactions between surface layers of LPS (Ra mutants) in aqueous media have been studied using a surface force apparatus (SFA), exploring the effects of temperature and divalent Ca2+ cations. Complementary dynamic light scattering (DLS) characterization suggests that vesicle-like aggregates of diameter ∼28-80 nm are formed by LPS-Ra in aqueous media. SFA results show that LPS-Ra vesicles adsorb weakly onto mica in pure water at room temperature (RT) and the surface layers are readily squeezed out as the two surfaces approach each other. However, upon addition of calcium (Ca2+) cations at near physiological concentration (2.5 mM) at RT, LPS multilayers or deformed LPS liposomes on mica are observed, presumably due to bridging between LPS phosphate groups and between LPS phosphates and negatively charged mica mediated by Ca2+, with a hard wall repulsion at surface separation D0 ∼ 30-40 nm. At 40 °C, which is above the LPS-Ra β-α acyl chain melting temperature (Tm = 36 °C), fusion events between the surface layers under compression could be observed, evident from δD ∼ 8-10 nm steps in the force-distance profiles attributed to LPS-bilayers being squeezed out due to enhanced fluidity of the LPS acyl-chain, with a final hard wall surface separation D0 ∼ 8-10 nm corresponding to the thickness of a single bilayer confined between the surfaces. These unprecedented SFA results reveal intricate structural responses of LPS surface layers to temperature and Ca2+, with implications to our fundamental understanding of the structures and interactions of bacterial membranes.
Collapse
Affiliation(s)
- Christian Redeker
- School of Chemistry , University of Bristol , Cantock's Close, Bristol BS8 1TS , United Kingdom
| | - Wuge H Briscoe
- School of Chemistry , University of Bristol , Cantock's Close, Bristol BS8 1TS , United Kingdom
| |
Collapse
|
13
|
Fan X, Xu W, Han J, Jiang X, Wink M, Wu G. Antimicrobial peptide hybrid fluorescent protein based sensor array discriminate ten most frequent clinic isolates. Biochim Biophys Acta Gen Subj 2019; 1863:1158-1166. [DOI: 10.1016/j.bbagen.2019.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/14/2019] [Accepted: 04/10/2019] [Indexed: 01/30/2023]
|
14
|
Jefferies D, Shearer J, Khalid S. Role of O-Antigen in Response to Mechanical Stress of the E. coli Outer Membrane: Insights from Coarse-Grained MD Simulations. J Phys Chem B 2019; 123:3567-3575. [DOI: 10.1021/acs.jpcb.8b12168] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Damien Jefferies
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Jonathan Shearer
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Syma Khalid
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| |
Collapse
|
15
|
Rodriguez-Loureiro I, Latza VM, Fragneto G, Schneck E. Conformation of Single and Interacting Lipopolysaccharide Surfaces Bearing O-Side Chains. Biophys J 2019; 114:1624-1635. [PMID: 29642032 DOI: 10.1016/j.bpj.2018.02.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/08/2018] [Accepted: 02/13/2018] [Indexed: 10/17/2022] Open
Abstract
The outer surfaces of Gram-negative bacteria are composed of lipopolysaccharide (LPS) molecules exposing oligo- and polysaccharides to the aqueous environment. This unique, structurally complex biological interface is of great scientific interest as it mediates the interaction of bacteria with antimicrobial agents as well as with neighboring bacteria in colonies and biofilms. Structural studies on LPS surfaces, however, have so far dealt almost exclusively with rough mutant LPS of reduced molecular complexity and limited biological relevance. Here, by using neutron reflectometry, we structurally characterize planar monolayers of wild-type LPS from Escherichia coli O55:B5 featuring strain-specific O-side chains in the presence and absence of divalent cations and under controlled interaction conditions. The model used for the reflectivity analysis is self-consistent and based on the volume fraction profiles of all chemical components. The saccharide profiles are found to be bimodal, with dense inner oligosaccharides and more dilute, extended O-side chains. For interacting LPS monolayers, we establish the pressure-distance curve and determine the distance-dependent saccharide conformation.
Collapse
Affiliation(s)
| | - Victoria M Latza
- Biomaterials Department, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Giovanna Fragneto
- Large Scale Structures (LSS) Group, Institut Laue-Langevin, Grenoble, France
| | - Emanuel Schneck
- Biomaterials Department, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
| |
Collapse
|
16
|
Micciulla S, Gerelli Y, Schneck E. Structure and Conformation of Wild-Type Bacterial Lipopolysaccharide Layers at Air-Water Interfaces. Biophys J 2019; 116:1259-1269. [PMID: 30878200 DOI: 10.1016/j.bpj.2019.02.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 02/13/2019] [Accepted: 02/21/2019] [Indexed: 10/27/2022] Open
Abstract
The outer membrane of Gram-negative bacteria is of great scientific interest because it mediates the action of antimicrobial agents. The membrane surface is composed of lipopolysaccharide (LPS) molecules with negatively charged oligosaccharide headgroups. To a certain fraction, LPSs additionally display linear polysaccharides termed O-side chains (OSCs). Structural studies on bacterial outer surfaces models, based on LPS monolayers at air-water interfaces, have so far dealt only with rough mutant LPSs lacking these OSCs. Here, we characterize monolayers of wild-type LPS from Escherichia coli O55:B5 featuring strain-specific OSCs in the presence of defined concentrations of monovalent and divalent ions. Pressure-area isotherms yield insight into in-plane molecular interactions and monolayer elastic moduli. Structural investigations by x-ray and neutron reflectometry reveal the saccharide conformation and allow quantifying the area per molecule and the fraction of LPS molecules carrying OSCs. The OSC conformation is satisfactorily described by the self-consistent field theory for end-grafted polymer brushes. The monolayers exhibit a significant structural response to divalent cations, which goes beyond generic electrostatic screening.
Collapse
Affiliation(s)
- Samantha Micciulla
- Institut Laue-Langevin, Grenoble, France; Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | | | - Emanuel Schneck
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
| |
Collapse
|
17
|
Combining scattering and computer simulation for the study of biomolecular soft interfaces. Curr Opin Colloid Interface Sci 2018. [DOI: 10.1016/j.cocis.2018.06.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|
18
|
Matsuzaki T, Ito H, Chevyreva V, Makky A, Kaufmann S, Okano K, Kobayashi N, Suganuma M, Nakabayashi S, Yoshikawa HY, Tanaka M. Adsorption of galloyl catechin aggregates significantly modulates membrane mechanics in the absence of biochemical cues. Phys Chem Chem Phys 2018; 19:19937-19947. [PMID: 28721420 DOI: 10.1039/c7cp02771k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Physical interactions of four major green tea catechin derivatives with cell membrane models were systemically investigated. Catechins with the galloyl moiety caused the aggregation of small unilamellar vesicles and an increase in the surface pressure of lipid monolayers, while those without did not. Differential scanning calorimetry revealed that, in a low concentration regime (≤10 μM), catechin molecules are not significantly incorporated into the hydrophobic core of lipid membranes as substitutional impurities. Partition coefficient measurements revealed that the galloyl moiety of catechin and the cationic quaternary amine of lipids dominate the catechin-membrane interaction, which can be attributed to the combination of electrostatic and cation-π interactions. Finally, we shed light on the mechanical consequence of catechin-membrane interactions using the Fourier-transformation of the membrane fluctuation. Surprisingly, the incubation of cell-sized vesicles with 1 μM galloyl catechins, which is comparable to the level in human blood plasma after green tea consumption, significantly increased the bending stiffness of the membranes by a factor of more than 60, while those without the galloyl moiety had no detectable influence. Atomic force microscopy and circular dichroism spectroscopy suggest that the membrane stiffening is mainly attributed to the adsorption of galloyl catechin aggregates to the membrane surfaces. These results contribute to our understanding of the physical and thus the generic functions of green tea catechins in therapeutics, such as cancer prevention.
Collapse
Affiliation(s)
- Takahisa Matsuzaki
- Department of Chemistry, Saitama University, Sakura-ku, Saitama, 338-8570, Japan.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Clifton LA, Ciesielski F, Skoda MWA, Paracini N, Holt SA, Lakey JH. The Effect of Lipopolysaccharide Core Oligosaccharide Size on the Electrostatic Binding of Antimicrobial Proteins to Models of the Gram Negative Bacterial Outer Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:3485-94. [PMID: 27003358 PMCID: PMC4854487 DOI: 10.1021/acs.langmuir.6b00240] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 02/28/2016] [Indexed: 05/23/2023]
Abstract
Understanding the electrostatic interactions between bacterial membranes and exogenous proteins is crucial to designing effective antimicrobial agents against Gram-negative bacteria. Here we study, using neutron reflecometry under multiple isotopic contrast conditions, the role of the uncharged sugar groups in the outer core region of lipopolysaccharide (LPS) in protecting the phosphate-rich inner core region from electrostatic interactions with antimicrobial proteins. Models of the asymmetric Gram negative outer membrane on silicon were prepared with phopshatidylcholine (PC) in the inner leaflet (closest to the silicon), whereas rough LPS was used to form the outer leaflet (facing the bulk solution). We show how salt concentration can be used to reversibly alter the binding affinity of a protein antibiotic colicin N (ColN) to the anionic LPS confirming that the interaction is electrostatic in nature. By examining the interaction of ColN with two rough LPS types with different-sized core oligosaccharide regions we demonstrate the role of uncharged sugars in blocking short-range electrostatic interactions between the cationic antibiotics and the vulnerable anionic phosphate groups.
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
| | - Filip Ciesielski
- Department of Plant Sciences, University of Oxford , Oxford, OX1 3RB, United Kingdom
| | - Maximilian W A Skoda
- 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
| | - Nicolò Paracini
- Institute for Cell and Molecular Biosciences, Newcastle University , Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Stephen A Holt
- Bragg Institute, Australian Nuclear Science and Technology Organisation , Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Jeremy H Lakey
- Institute for Cell and Molecular Biosciences, Newcastle University , Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom
| |
Collapse
|
20
|
A MARTINI extension for Pseudomonas aeruginosa PAO1 lipopolysaccharide. J Mol Graph Model 2016; 63:125-33. [DOI: 10.1016/j.jmgm.2015.12.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/16/2015] [Accepted: 12/11/2015] [Indexed: 11/24/2022]
|
21
|
Herrmann M, Schneck E, Gutsmann T, Brandenburg K, Tanaka M. Bacterial lipopolysaccharides form physically cross-linked, two-dimensional gels in the presence of divalent cations. SOFT MATTER 2015; 11:6037-6044. [PMID: 26136185 DOI: 10.1039/c5sm01002k] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We established a bacterial membrane model with monolayers of bacterial lipopolysaccharides (LPS Re and LPS Ra) and quantified their viscoelastic properties by using an interfacial stress rheometer coupled to a Langmuir film balance. LPS Re monolayers exhibited purely viscous behaviour in the absence of calcium ions, while the same monolayers underwent a viscous-to-elastic transition upon compression in the presence of Ca(2+). Our results demonstrated for the first time that LPSs in bacterial outer membranes can form two-dimensional elastic networks in the presence of Ca(2+). Different from LPS Re monolayers, the LPS Ra monolayers showed a very similar rheological transition both in the presence and absence of Ca(2+), suggesting that longer saccharide chains can form 2D physical gels even in the absence of Ca(2+). By exposure of the monolayers to the antimicrobial peptide protamine, we could directly monitor the differences in resistance of bacterial membranes according to the presence of calcium.
Collapse
Affiliation(s)
- Moritz Herrmann
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, D69120 Heidelberg, Germany.
| | | | | | | | | |
Collapse
|
22
|
Korytowski A, Abuillan W, Makky A, Konovalov O, Tanaka M. Impact of Lipid Oxidization on Vertical Structures and Electrostatics of Phospholipid Monolayers Revealed by Combination of Specular X-ray Reflectivity and Grazing-Incidence X-ray Fluorescence. J Phys Chem B 2015; 119:9787-94. [PMID: 26125947 DOI: 10.1021/acs.jpcb.5b04451] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The influence of phospholipid oxidization of floating monolayers on the structure perpendicular to the global plane and on the density profiles of ions near the lipid monolayer has been investigated by a combination of grazing incidence X-ray fluorescence (GIXF) and specular X-ray reflectivity (XRR). Systematic variation of the composition of the floating monolayers unravels changes in the thickness, roughness and electron density of the lipid monolayers as a function of molar fraction of oxidized phospholipids. Simultaneous GIXF measurements enable one to qualitatively determine the element-specific density profiles of monovalent (K(+) or Cs(+)) and divalent ions (Ca(2+)) in the vicinity of the interface in the presence and absence of two types of oxidized phospholipids (PazePC and PoxnoPC) with high spatial accuracy (±5 Å). We found the condensation of Ca(2+) near carboxylated PazePC was more pronounced compared to PoxnoPC with an aldehyde group. In contrast, the condensation of monovalent ions could hardly be detected even for pure oxidized phospholipid monolayers. Moreover, pure phospholipid monolayers exhibited almost no ion specific condensation near the interface. The quantitative studies with well-defined floating monolayers revealed how the elevation of lipid oxidization level alters the structures and functions of cell membranes.
Collapse
Affiliation(s)
- Agatha Korytowski
- †Physical Chemistry of Biosystems, Physical Chemistry Institute, University of Heidelberg, 69120 Heidelberg, Germany
| | - Wasim Abuillan
- †Physical Chemistry of Biosystems, Physical Chemistry Institute, University of Heidelberg, 69120 Heidelberg, Germany
| | - Ali Makky
- †Physical Chemistry of Biosystems, Physical Chemistry Institute, University of Heidelberg, 69120 Heidelberg, Germany.,‡Institut Galien Paris Sud, Faculté de Pharmacie-Université Paris-Sud, 5 rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France
| | - Oleg Konovalov
- §European Synchrotron Radiation Facility (ESRF), Grenoble Cedex 9 38053, France
| | - Motomu Tanaka
- †Physical Chemistry of Biosystems, Physical Chemistry Institute, University of Heidelberg, 69120 Heidelberg, Germany.,∥Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, 606-8501 Kyoto, Japan
| |
Collapse
|
23
|
Pink DA, Hasan FM, Quinn BE, Winterhalter M, Mohan M, Gill TA. Interaction of protamine with gram‐negative bacteria membranes: possible alternative mechanisms of internalization in
Escherichia coli
,
Salmonella typhimurium
and
Pseudomonas aeruginosa. J Pept Sci 2014; 20:240-50. [DOI: 10.1002/psc.2610] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 11/14/2013] [Accepted: 12/02/2013] [Indexed: 11/08/2022]
Affiliation(s)
- David. A. Pink
- Department of Physics St. Francis Xavier University Antigonish NS B2G 2W5 Canada
| | - Fida M. Hasan
- Department of Process Engineering and Applied Science Dalhousie University Halifax NS B3J 2X4 Canada
| | - Bonnie E. Quinn
- Department of Physics St. Francis Xavier University Antigonish NS B2G 2W5 Canada
| | | | - Mukund Mohan
- Department of Process Engineering and Applied Science Dalhousie University Halifax NS B3J 2X4 Canada
| | - Tom A. Gill
- Department of Process Engineering and Applied Science Dalhousie University Halifax NS B3J 2X4 Canada
| |
Collapse
|
24
|
Pustam A, Smith C, Deering C, Grosicki KMT, Leng TY, Lin S, Yang J, Pink D, Gill T, Graham L, Derksen D, Bishop C, Demont ME, Wyeth RC, Smith-Palmer T. Interactions of protamine with the marine bacterium, Pseudoalteromonas sp. NCIMB 2021. Lett Appl Microbiol 2013; 58:225-30. [PMID: 24138125 DOI: 10.1111/lam.12177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/11/2013] [Accepted: 10/14/2013] [Indexed: 11/27/2022]
Abstract
UNLABELLED Pseudoalteromonas sp. NCIMB 2021 (NCIMB 2021) was grown in synthetic seawater (SSW) containing pyruvate, in the presence (SSW(++) ) and absence (SSW(-) ) of divalent cations. Cultures contained single cells. Addition of the cationic antibacterial peptide (CAP), protamine, did not inhibit, but rather increased, the growth of NCIMB 2021 in SSW(++) and caused the bacteria to grow in chains. Bacterial growth was assessed using turbidity, cell counts and the sodium salt of resazurin. In SSW(-) , NCIMB 2021 was no longer resistant to protamine. The minimum inhibitory concentration (MIC) was 5 mg ml(-1) . SIGNIFICANCE AND IMPACT OF THE STUDY Protamine is a cationic antimicrobial peptide (CAP), which is active against a variety of bacteria. This is the first in-depth study of the interaction of protamine with a marine bacterium, Pseudoalteromonas sp. NCIMB 2021. Our results show that protamine is only active in seawater in the absence of divalent cations. In the presence of the divalent cations, Mg(2+) and Ca(2+) , protamine enhances the growth of Pseudoalteromonas sp. NCIMB 2021 and produces chains rather than individual cells. These are important considerations when deciding on applications for protamine and in terms of understanding its mechanism of action.
Collapse
Affiliation(s)
- A Pustam
- Chemistry Department, St Francis Xavier University, Antigonish, NS, Canada; Centre for Biofouling Research, St Francis Xavier University, Antigonish, NS, Canada
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
|
26
|
Abuillan W, Schneck E, Körner A, Brandenburg K, Gutsmann T, Gill T, Vorobiev A, Konovalov O, Tanaka M. Physical interactions of fish protamine and antisepsis peptide drugs with bacterial membranes revealed by combination of specular x-ray reflectivity and grazing-incidence x-ray fluorescence. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:012705. [PMID: 23944490 DOI: 10.1103/physreve.88.012705] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Indexed: 06/02/2023]
Abstract
As a defined model of outer membranes of gram negative bacteria, we investigated the interaction of monolayers of lipopolysacchrides from Salmonella enterica rough strains R90 (LPS Ra) with natural and synthetic peptides. The fine structures perpendicular to the membrane plane and the ion distribution near the interface were determined by specular x-ray reflectivity (XRR) and grazing-incidence x-ray fluorescence (GIXF) in the presence and absence of divalent cations. The unique combination of XRR and GIXF allows for the quantitative identification of different modes of interactions in a high spatial resolution, which cannot be assessed by other experimental methods. Natural fish protamine disrupts the stratified membrane structures in the absence of Ca(2+) ions, while staying away from the membrane surface in the presence of Ca(2+) ions. In contrast, synthetic antisepsis peptide Pep 19-2.5 weakly adsorbs to the membrane and stays near the uncharged sugar units even in the absence of Ca(2+). In the presence of Ca(2+), Pep 19-2.5 can reach the negatively charged inner core without destroying the barrier capability against ions.
Collapse
Affiliation(s)
- Wasim Abuillan
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, D69120 Heidelberg, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Le Brun A, Clifton LA, Halbert CE, Lin B, Meron M, Holden PJ, Lakey JH, Holt SA. Structural characterization of a model gram-negative bacterial surface using lipopolysaccharides from rough strains of Escherichia coli. Biomacromolecules 2013; 14:2014-22. [PMID: 23617615 PMCID: PMC3679557 DOI: 10.1021/bm400356m] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/18/2013] [Indexed: 12/29/2022]
Abstract
Lipopolysaccharides (LPS) make up approximately 75% of the Gram-negative bacterial outer membrane (OM) surface, but because of the complexity of the molecule, there are very few model OMs that include LPS. The LPS molecule consists of lipid A, which anchors the LPS within the OM, a core polysaccharide region, and a variable O-antigen polysaccharide chain. In this work we used RcLPS (consisting of lipid A plus the first seven sugars of the core polysaccharide) from a rough strain of Escherichia coli to form stable monolayers of LPS at the air-liquid interface. The vertical structure RcLPS monolayers were characterized using neutron and X-ray reflectometry, while the lateral structure was investigated using grazing incidence X-ray diffraction and Brewster angle microscopy. It was found that RcLPS monolayers at surface pressures of 20 mN m(-1) and above are resolved as hydrocarbon tails, an inner headgroup, and an outer headgroup of polysaccharide with increasing solvation from tails to outer headgroups. The lateral organization of the hydrocarbon lipid chains displays an oblique hexagonal unit cell at all surface pressures, with only the chain tilt angle changing with surface pressure. This is in contrast to lipid A, which displays hexagonal or, above 20 mN m(-1), distorted hexagonal packing. This work provides the first complete structural analysis of a realistic E. coli OM surface model.
Collapse
Affiliation(s)
- Anton
P. Le Brun
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Luke A. Clifton
- ISIS Neutron Facility, STFC Rutherford
Appleton Laboratory, Didcot, Oxfordshire
OX11 0QX, United Kingdom
| | - Candice E. Halbert
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee
37831, United States
| | - Binhua Lin
- Consortium
of Advanced Radiation
Sources (CARS), University of Chicago,
Chicago, Illinois 60637, United States
| | - Mati Meron
- Consortium
of Advanced Radiation
Sources (CARS), University of Chicago,
Chicago, Illinois 60637, United States
| | - Peter J. Holden
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Jeremy H. Lakey
- Institute for Cell and Molecular
Biosciences, Newcastle University, Framlington
Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Stephen A. Holt
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| |
Collapse
|
28
|
Roberts JM, Graham LL, Quinn B, Pink DA. Modeling the surface of campylobacter fetus: Protein surface layer stability and resistance to cationic antimicrobial peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1143-52. [DOI: 10.1016/j.bbamem.2012.10.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 10/13/2012] [Accepted: 10/21/2012] [Indexed: 12/14/2022]
|
29
|
Alexander DB, Iigo M, Yamauchi K, Suzui M, Tsuda H. Lactoferrin: an alternative view of its role in human biological fluids. Biochem Cell Biol 2012; 90:279-306. [PMID: 22553915 DOI: 10.1139/o2012-013] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Lactoferrin is a major component of biologically important mucosal fluids and of the specific granules of neutrophils. Understanding its biological function is essential for understanding neutrophil- and mucosal-mediated immunity. In this review, we reevaluate the in vivo functions of human lactoferrin (hLF) emphasizing in vivo studies and in vitro studies performed in biologically relevant fluids. We discuss the evidence in the literature that supports (or does not support) proposed roles for hLF in mucosal immunity and in neutrophil function. We argue that the current literature supports a microbiostatic role, but not a microbicidal role, for hLF in vivo. The literature also supports a role for hLF in inhibiting colonization and infection of epithelial surfaces by microorganisms and in protecting tissues from neutrophil-mediated damage. Using this information, we briefly discuss hLF in the context of the complex biological fluids in which it is found.
Collapse
Affiliation(s)
- David B Alexander
- Laboratory of Nanotoxicology Project, Nagoya City University, 3-1 Tanabedohri, Mizuho-ku, Nagoya 467-8603, Japan.
| | | | | | | | | |
Collapse
|
30
|
Ghosh SK, Castorph S, Konovalov O, Salditt T, Jahn R, Holt M. Measuring Ca2+-induced structural changes in lipid monolayers: implications for synaptic vesicle exocytosis. Biophys J 2012; 102:1394-402. [PMID: 22455922 DOI: 10.1016/j.bpj.2012.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 12/04/2011] [Accepted: 01/05/2012] [Indexed: 01/08/2023] Open
Abstract
Synaptic vesicles (SVs) are small, membrane-bound organelles that are found in the synaptic terminal of neurons. Although tremendous progress has been made in understanding the protein machinery that drives fusion of SVs with the presynaptic membrane, little progress has been made in understanding changes in the membrane structure that accompany this process. We used lipid monolayers of defined composition to mimic biological membranes, which were probed by x-ray reflectivity and grazing incidence x-ray diffraction. These techniques allowed us to successfully monitor structural changes in the membranes at molecular level, both in response to injection of SVs in the subphase below the monolayer, as well as to physiological cues involved in neurotransmitter release, such as increases in the concentration of the membrane lipid PIP(2), or addition of physiological levels of Ca(2+). Such structural changes may well modulate vesicle fusion in vivo.
Collapse
Affiliation(s)
- Sajal Kumar Ghosh
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
| | | | | | | | | | | |
Collapse
|
31
|
Jeworrek C, Evers F, Howe J, Brandenburg K, Tolan M, Winter R. Effects of specific versus nonspecific ionic interactions on the structure and lateral organization of lipopolysaccharides. Biophys J 2011; 100:2169-77. [PMID: 21539784 DOI: 10.1016/j.bpj.2011.03.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 02/23/2011] [Accepted: 03/17/2011] [Indexed: 11/27/2022] Open
Abstract
We report x-ray reflectivity and grazing incidence x-ray diffraction measurements of lipopolysaccharide (LPS) monolayers at the water-air interface. Our investigations reveal that the structure and lateral ordering of the LPS molecules is very different from phospholipid systems and can be modulated by the ionic strength of the aqueous subphase in an ion-dependent manner. Our findings also indicate differential effects of monovalent and divalent ions on the two-dimensional ordering of lipid domains. Na(+) ions interact unspecifically with LPS molecules based on their ability to efficiently screen the negative charges of the LPS molecules, whereas Ca(2+) ions interact specifically by cross-linking adjacent molecules in the monolayer. At low lateral pressures, Na(+) ions present in the subphase lead to a LPS monolayer structure ordered over large areas with high compressibility, nearly hexagonal packing of the hydrocarbon chains, and high density in the LPS headgroup region. At higher film pressures, the LPS monolayer becomes more rigid and results in a less perfect, oblique packing of the LPS hydrocarbon chains as well as a smaller lateral size of highly ordered domains on the monolayer. Furthermore, associated with the increased surface pressure, a conformational change of the sugar headgroups occurs, leading to a thickening of the entire LPS monolayer structure. The effect of Ca(2+) ions in the subphase is to increase the rigidity of the LPS monolayer, leading to an oblique packing of the hydrocarbon chains already at low film pressures, an upright orientation of the sugar moieties, and much smaller sizes of ordered domains in the plane of the monolayer. In the presence of both Na(+)- and Ca(2+) ions in the subphase, the screening effect of Na(+) is predominant at low film pressures, whereas, at higher film pressures, the structure and lateral organization of LPS molecules is governed by the influence of Ca(2+) ions. The unspecific charge-screening effect of the Na(+) ions on the conformation of the sugar moiety becomes less dominant at biologically relevant lateral pressures.
Collapse
Affiliation(s)
- Christoph Jeworrek
- Physical Chemistry I, Faculty of Chemistry, TU Dortmund University, Dortmund, Germany
| | | | | | | | | | | |
Collapse
|
32
|
Tanaka M, Schneck E, Yoshikawa HY, Rossetti FF. Physical chemistry of biological interfaces: generic and specific roles of soft interlayers. Chem Asian J 2011; 6:1728-38. [PMID: 21548102 DOI: 10.1002/asia.201100112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2011] [Indexed: 11/09/2022]
Abstract
Nature defines the spatial boundaries between different phases using membranes, and the interfacial interactions are mediated by soft biopolymer interlayers that contain various carbohydrates. This Review provides a comprehensive overview on the interplay of generic and specific interactions at cell-cell and cell-tissue interfaces. A focus will be put on the combination of defined model systems, experimental techniques in real- and reciprocal space, and theoretical simulations.
Collapse
Affiliation(s)
- Motomu Tanaka
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany.
| | | | | | | |
Collapse
|
33
|
Quantitative determination of ion distributions in bacterial lipopolysaccharide membranes by grazing-incidence X-ray fluorescence. Proc Natl Acad Sci U S A 2010; 107:9147-51. [PMID: 20442333 DOI: 10.1073/pnas.0913737107] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A model of the outer membrane of Gram-negative bacteria was created by the deposition of a monolayer of purified rough mutant lipopolysaccharides at an air/water interface. The density profiles of monovalent (K(+)) and divalent (Ca(2+)) cations normal to the lipopolysaccharides (LPS) monolayers were investigated using grazing-incidence X-ray fluorescence. In the absence of Ca(2+), a K(+) concentration peak was found in the negatively charged LPS headgroup region. With the addition of CaCl(2), Ca(2+) ions almost completely displaced K(+) ions from the headgroup region. By integrating the experimentally reconstructed excess ion density profiles, we obtained an accurate measurement of the effective charge density of LPS monolayers. The experimental findings were compared to the results of Monte Carlo simulations based on a coarse-grained minimal model of LPS molecules and showed excellent agreement.
Collapse
|