1
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Ryoo D, Hwang H, Gumbart JC. Thicket and Mesh: How the Outer Membrane Can Resist Tension Imposed by the Cell Wall. J Phys Chem B 2024; 128:5371-5377. [PMID: 38787347 PMCID: PMC11163421 DOI: 10.1021/acs.jpcb.3c08510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024]
Abstract
The cell envelope of Gram-negative bacteria is composed of an outer membrane (OM) and an inner membrane (IM) and a peptidoglycan cell wall (CW) between them. Combined with Braun's lipoprotein (Lpp), which connects the OM and the CW, and numerous membrane proteins that exist in both OM and IM, the cell envelope creates a mechanically stable environment that resists various physical and chemical perturbations to the cell, including turgor pressure caused by the solute concentration difference between the cytoplasm of the cell and the extracellular environment. Previous computational studies have explored how individual components (OM, IM, and CW) can resist turgor pressure although combinations of them have been less well studied. To that end, we constructed multiple OM-CW systems, including the Lpp connections with the CW under increasing degrees of strain. The results show that the OM can effectively resist the tension imposed by the CW, shrinking by only 3-5% in area even when the CW is stretched to 2.5× its relaxed area. The area expansion modulus of the system increases with increasing CW strain, although the OM remains a significant contributor to the envelope's mechanical stability. Additionally, we find that when the protein TolC is embedded in the OM, its stiffness increases.
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Affiliation(s)
- David Ryoo
- Interdisciplinary
Bioengineering Graduate Program, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - Hyea Hwang
- School
of Materials Science and Engineering, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
| | - James C. Gumbart
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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2
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Stephani J, Gerhards L, Khairalla B, Solov’yov IA, Brand I. How do Antimicrobial Peptides Interact with the Outer Membrane of Gram-Negative Bacteria? Role of Lipopolysaccharides in Peptide Binding, Anchoring, and Penetration. ACS Infect Dis 2024; 10:763-778. [PMID: 38259029 PMCID: PMC10862549 DOI: 10.1021/acsinfecdis.3c00673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/31/2023] [Accepted: 01/02/2024] [Indexed: 01/24/2024]
Abstract
Gram-negative bacteria possess a complex structural cell envelope that constitutes a barrier for antimicrobial peptides that neutralize the microbes by disrupting their cell membranes. Computational and experimental approaches were used to study a model outer membrane interaction with an antimicrobial peptide, melittin. The investigated membrane included di[3-deoxy-d-manno-octulosonyl]-lipid A (KLA) in the outer leaflet and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) in the inner leaflet. Molecular dynamics simulations revealed that the positively charged helical C-terminus of melittin anchors rapidly into the hydrophilic headgroup region of KLA, while the flexible N-terminus makes contacts with the phosphate groups of KLA, supporting melittin penetration into the boundary between the hydrophilic and hydrophobic regions of the lipids. Electrochemical techniques confirmed the binding of melittin to the model membrane. To probe the peptide conformation and orientation during interaction with the membrane, polarization modulation infrared reflection absorption spectroscopy was used. The measurements revealed conformational changes in the peptide, accompanied by reorientation and translocation of the peptide at the membrane surface. The study suggests that melittin insertion into the outer membrane affects its permeability and capacitance but does not disturb the membrane's bilayer structure, indicating a distinct mechanism of the peptide action on the outer membrane of Gram-negative bacteria.
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Affiliation(s)
- Justus
C. Stephani
- Institute
of Physics, Carl von Ossietzky University
of Oldenburg, 26111 Oldenburg, Germany
| | - Luca Gerhards
- Institute
of Physics, Carl von Ossietzky University
of Oldenburg, 26111 Oldenburg, Germany
| | - Bishoy Khairalla
- Department
of Chemistry, Carl von Ossietzky University
of Oldenburg, 26111 Oldenburg, Germany
| | - Ilia A. Solov’yov
- Institute
of Physics, Carl von Ossietzky University
of Oldenburg, 26111 Oldenburg, Germany
- Research
Center Neurosensory Science, Carl von Ossietzky
University of Oldenburg, 26111 Oldenburg, Germany
- CeNaD—Center
for Nanoscale Dynamics, Carl von Ossietzky
University of Oldenburg, 26111 Oldenburg, Germany
| | - Izabella Brand
- Department
of Chemistry, Carl von Ossietzky University
of Oldenburg, 26111 Oldenburg, Germany
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3
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Serizawa T, Yamaguchi S, Sugiura K, Marten R, Yamamoto A, Hata Y, Sawada T, Tanaka H, Tanaka M. Antibacterial Synthetic Nanocelluloses Synergizing with a Metal-Chelating Agent. ACS APPLIED BIO MATERIALS 2024; 7:246-255. [PMID: 37967519 PMCID: PMC10792664 DOI: 10.1021/acsabm.3c00846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/02/2023] [Accepted: 11/02/2023] [Indexed: 11/17/2023]
Abstract
Antibacterial materials composed of biodegradable and biocompatible constituents that are produced via eco-friendly synthetic strategies will become an attractive alternative to antibiotics to combat antibiotic-resistant bacteria. In this study, we demonstrated the antibacterial properties of nanosheet-shaped crystalline assemblies of enzymatically synthesized aminated cellulose oligomers (namely, surface-aminated synthetic nanocelluloses) and their synergy with a metal-chelating antibacterial agent, ethylenediaminetetraacetic acid (EDTA). Growth curves and colony counting assays revealed that the surface-aminated cellulose assemblies had an antibacterial effect against Gram-negative Escherichia coli (E. coli). The cationic assemblies appeared to destabilize the cell wall of E. coli through electrostatic interactions with anionic lipopolysaccharide (LPS) molecules on the outer membrane. The antibacterial properties were significantly enhanced by the concurrent use of EDTA, which potentially removed metal ions from LPS molecules, resulting in synergistic bactericidal effects. No antibacterial activity of the surface-aminated cellulose assemblies was observed against Gram-positive Staphylococcus aureus even in the presence of EDTA, further supporting the contribution of electrostatic interactions between the cationic assemblies and anionic LPS to the activity against Gram-negative bacteria. Analysis using quartz crystal microbalance with dissipation monitoring revealed the attractive interaction of the surface-aminated cellulose assembly with LPS Ra monolayers artificially produced on the device substrate.
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Affiliation(s)
- Takeshi Serizawa
- Department
of Chemical Science and Engineering, School of Materials and Chemical
Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Saeko Yamaguchi
- Department
of Chemical Science and Engineering, School of Materials and Chemical
Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Kai Sugiura
- Department
of Chemical Science and Engineering, School of Materials and Chemical
Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Ramona Marten
- Physical
Chemistry of Biosystems, Institute of Physical Chemistry, Heidelberg University, Heidelberg D69120, Germany
- Center
for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan
| | - Akihisa Yamamoto
- Center
for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan
| | - Yuuki Hata
- Department
of Chemical Science and Engineering, School of Materials and Chemical
Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Toshiki Sawada
- Department
of Chemical Science and Engineering, School of Materials and Chemical
Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Hiroshi Tanaka
- Department
of Chemical Science and Engineering, School of Materials and Chemical
Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Motomu Tanaka
- Physical
Chemistry of Biosystems, Institute of Physical Chemistry, Heidelberg University, Heidelberg D69120, Germany
- Center
for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan
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4
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Dommer A, Wauer NA, Angle KJ, Davasam A, Rubio P, Luo M, Morris CK, Prather KA, Grassian VH, Amaro RE. Revealing the Impacts of Chemical Complexity on Submicrometer Sea Spray Aerosol Morphology. ACS CENTRAL SCIENCE 2023; 9:1088-1103. [PMID: 37396863 PMCID: PMC10311664 DOI: 10.1021/acscentsci.3c00184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Indexed: 07/04/2023]
Abstract
Sea spray aerosol (SSA) ejected through bursting bubbles at the ocean surface is a complex mixture of salts and organic species. Submicrometer SSA particles have long atmospheric lifetimes and play a critical role in the climate system. Composition impacts their ability to form marine clouds, yet their cloud-forming potential is difficult to study due to their small size. Here, we use large-scale molecular dynamics (MD) simulations as a "computational microscope" to provide never-before-seen views of 40 nm model aerosol particles and their molecular morphologies. We investigate how increasing chemical complexity impacts the distribution of organic material throughout individual particles for a range of organic constituents with varying chemical properties. Our simulations show that common organic marine surfactants readily partition between both the surface and interior of the aerosol, indicating that nascent SSA may be more heterogeneous than traditional morphological models suggest. We support our computational observations of SSA surface heterogeneity with Brewster angle microscopy on model interfaces. These observations indicate that increased chemical complexity in submicrometer SSA leads to a reduced surface coverage by marine organics, which may facilitate water uptake in the atmosphere. Our work thus establishes large-scale MD simulations as a novel technique for interrogating aerosols at the single-particle level.
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5
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Furikado I, Habe T, Inoue S, Tanaka M. Thermodynamics and Viscoelastic Property of Interface Unravel Combined Functions of Cationic Surfactant and Aromatic Alcohol against Gram-Negative Bacteria. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37289662 DOI: 10.1021/acs.langmuir.3c00862] [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), the major constituents of the outer membranes of Gram-negative bacteria, play a key role in protecting bacteria against antibiotics and antibacterial agents. In this study, we investigated how a mixture of cationic surfactants and aromatic alcohols, the base materials of widely used sanitizers, synergistically act on LPSs purified from Escherichia coli using isothermal titration calorimetry (ITC), surface tension measurements, and quartz crystal microbalance with dissipation (QCM-D). ITC data measured in the absence of Ca2+ ions showed the coexistence of exothermic and endothermic processes. The exotherm can be interpreted as the electrostatic binding of the cationic surfactant to the negatively charged LPS membrane surface, whereas the endotherm indicates the hydrophobic interaction between the hydrocarbon chains of the surfactants and LPSs. In the presence of Ca2+ ions, only an exothermic reaction was observed by ITC, and no entropically driven endotherm could be detected. Surface tension experiments further revealed that the co-adsorption of surfactants and LPS was synergistic, while that of surfactants and alcohol was negatively synergistic. Moreover, the QCM-D data indicated that the LPS membrane remained intact when the alcohol alone was added to the system. Intriguingly, the LPS membrane became highly susceptible to the combination of cationic surfactants and aromatic alcohols in the absence of Ca2+ ions. The obtained data provide thermodynamic and mechanical insights into the synergistic function of surfactants and alcohols in sanitation, which will enable the identification of the optimal combination of small molecules for a high hygiene level for the post-pandemic society.
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Affiliation(s)
- Ippei Furikado
- Analytical Science Research Laboratories, Kao Corporation, 1334, Minato, Wakayama-shi, Wakayama 640-8580, Japan
| | - Taichi Habe
- Analytical Science Research Laboratories, Kao Corporation, 1334, Minato, Wakayama-shi, Wakayama 640-8580, Japan
| | - Shigeto Inoue
- Analytical Science Research Laboratories, Kao Corporation, 1334, Minato, Wakayama-shi, Wakayama 640-8580, Japan
| | - Motomu Tanaka
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, Heidelberg University, Heidelberg 69120, Germany
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan
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6
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Šako M, Staniscia F, Schneck E, Netz RR, Kanduč M. Conditions for the stable adsorption of lipid monolayers to solid surfaces. PNAS NEXUS 2023; 2:pgad190. [PMID: 37383024 PMCID: PMC10299894 DOI: 10.1093/pnasnexus/pgad190] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 05/22/2023] [Accepted: 05/31/2023] [Indexed: 06/30/2023]
Abstract
Lipid monolayers are ubiquitous in biological systems and have multiple roles in biotechnological applications, such as lipid coatings that enhance colloidal stability or prevent surface fouling. Despite the great technological importance of surface-adsorbed lipid monolayers, the connection between their formation and the chemical characteristics of the underlying surfaces has remained poorly understood. Here, we elucidate the conditions required for stable lipid monolayers nonspecifically adsorbed on solid surfaces in aqueous solutions and water/alcohol mixtures. We use a framework that combines the general thermodynamic principles of monolayer adsorption with fully atomistic molecular dynamics simulations. We find that, very universally, the chief descriptor of adsorption free energy is the wetting contact angle of the solvent on the surface. It turns out that monolayers can form and remain thermodynamically stable only on substrates with contact angles above the adsorption contact angle, θads. Our analysis establishes that θads falls into a narrow range of around 60∘-70∘ in aqueous media and is only weakly dependent on the surface chemistry. Moreover, to a good approximation, θads is roughly determined by the ratio between the surface tensions of hydrocarbons and the solvent. Adding small amounts of alcohol to the aqueous medium lowers θads and thereby facilitates monolayer formation on hydrophilic solid surfaces. At the same time, alcohol addition weakens the adsorption strength on hydrophobic surfaces and results in a slowdown of the adsorption kinetics, which can be useful for the preparation of defect-free monolayers.
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Affiliation(s)
- Marin Šako
- Department of Theoretical Physics, Jožef Stefan Institute, Jamova 39, Ljubljana, 1000, Slovenia
| | - Fabio Staniscia
- Department of Theoretical Physics, Jožef Stefan Institute, Jamova 39, Ljubljana, 1000, Slovenia
| | - Emanuel Schneck
- Department of Physics, Technische Universität Darmstadt, Hochschulstrasse 8, Darmstadt 64289, Hesse, Germany
| | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, Berlin 14195, Germany
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7
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Cohen H, Wani NA, Ben Hur D, Migliolo L, Cardoso MH, Porat Z, Shimoni E, Franco OL, Shai Y. Interaction of Pexiganan (MSI-78)-Derived Analogues Reduces Inflammation and TLR4-Mediated Cytokine Secretion: A Comparative Study. ACS OMEGA 2023; 8:17856-17868. [PMID: 37251186 PMCID: PMC10210221 DOI: 10.1021/acsomega.3c00850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/28/2023] [Indexed: 05/31/2023]
Abstract
Antibiotic-resistant bacterial infections have increased the prevalence of sepsis and septic shock mortality worldwide and have become a global concern. Antimicrobial peptides (AMPs) show remarkable properties for developing new antimicrobial agents and host response modulatory therapies. A new series of AMPs derived from pexiganan (MSI-78) were synthesized. The positively charged amino acids were segregated at their N- and C-termini, and the rest of the amino acids created a hydrophobic core surrounded by positive charges and were modified to simulate the lipopolysaccharide (LPS). The peptides were investigated for their antimicrobial activity and LPS-induced cytokine release inhibition profile. Various biochemical and biophysical methods were used, including attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, microscale thermophoresis (MST), and electron microscopy. Two new AMPs, MSI-Seg-F2F and MSI-N7K, preserved their neutralizing endotoxin activity while reducing toxicity and hemolytic activity. Combining all of these properties makes the designed peptides potential candidates to eradicate bacterial infection and detoxify LPS, which might be useful for sepsis treatment.
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Affiliation(s)
- Hadar Cohen
- Department
of Biomolecular Sciences, The Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Naiem Ahmad Wani
- Department
of Biomolecular Sciences, The Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Daniel Ben Hur
- Department
of Biomolecular Sciences, The Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Ludovico Migliolo
- Departamento
de Engenharia Sanitária e Ambiental, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil
| | - Marlon H. Cardoso
- S-Inova,
Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117900, MS, Brazil
- Centro
de
Análises Proteômicas e Bioquímicas, Pós-Graduação
em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília 70790160, DF, Brazil
- Instituto
de Biociências (INBIO), Universidade
Federal de Mato Grosso do Sul, Cidade Universitária, Campo Grande 79070900, Mato Grosso do Sul, Brazil
| | - Ziv Porat
- The
Department of Life Sciences Core Facilities, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eyal Shimoni
- Department
of Chemical Research Support, The Weizmann
Institute of Science, Rehovot 76100, Israel
| | - Octavio Luiz Franco
- Departamento
de Engenharia Sanitária e Ambiental, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil
- S-Inova,
Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117900, MS, Brazil
- Centro
de
Análises Proteômicas e Bioquímicas, Pós-Graduação
em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília 70790160, DF, Brazil
| | - Yechiel Shai
- Department
of Biomolecular Sciences, The Weizmann Institute
of Science, Rehovot 76100, Israel
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8
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Stephan MS, Dunsing V, Pramanik S, Chiantia S, Barbirz S, Robinson T, Dimova R. Biomimetic asymmetric bacterial membranes incorporating lipopolysaccharides. Biophys J 2022:S0006-3495(22)03927-3. [PMID: 36523159 DOI: 10.1016/j.bpj.2022.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/30/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Gram-negative bacteria are equipped with a cell wall that contains a complex matrix of lipids, proteins, and glycans, which form a rigid layer protecting bacteria from the environment. Major components of this outer membrane are the high-molecular weight and amphiphilic lipopolysaccharides (LPSs). They form the extracellular part of a heterobilayer with phospholipids. Understanding LPS properties within the outer membrane is therefore important to develop new antimicrobial strategies. Model systems, such as giant unilamellar vesicles (GUVs), provide a suitable platform for exploring membrane properties and interactions. However, LPS molecules contain large polysaccharide parts that confer high water solubility, which makes LPS incorporation in artificial membranes difficult; this hindrance is exacerbated for LPS with long polysaccharide chains, i.e., the smooth LPS. Here, a novel emulsification step of the inverted emulsion method is introduced to incorporate LPS in the outer or the inner leaflet of GUVs, exclusively. We developed an approach to determine the LPS content on individual GUVs and quantify membrane asymmetry. The asymmetric membranes with outer leaflet LPS show incorporations of 1-16 mol % smooth LPS (corresponding to 16-79 wt %), while vesicles with inner leaflet LPS reach coverages of 2-7 mol % smooth LPS (28-60 wt %). Diffusion coefficient measurements in the obtained GUVs showed that increasing LPS concentrations in the membranes resulted in decreased diffusivity.
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Affiliation(s)
| | - Valentin Dunsing
- Aix-Marseille Université, CNRS, IBDM, Turing Center for Living Systems, Marseille, France; University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Germany
| | - Shreya Pramanik
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Salvatore Chiantia
- University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Germany
| | - Stefanie Barbirz
- Department Humanmedizin, MSB Medical School Berlin, Berlin, Germany
| | - Tom Robinson
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
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9
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Yamamoto A, Ikarashi T, Fukuma T, Suzuki R, Nakahata M, Miyata K, Tanaka M. Ion-specific nanoscale compaction of cysteine-modified poly(acrylic acid) brushes revealed by 3D scanning force microscopy with frequency modulation detection. NANOSCALE ADVANCES 2022; 4:5027-5036. [PMID: 36504747 PMCID: PMC9680925 DOI: 10.1039/d2na00350c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 09/14/2022] [Indexed: 06/17/2023]
Abstract
Stimuli-responsive polyelectrolyte brushes adapt their physico-chemical properties according to pH and ion concentrations of the solution in contact. We synthesized a poly(acrylic acid) bearing cysteine residues at side chains and a lipid head group at the terminal, and incorporated them into a phospholipid monolayer deposited on a hydrophobic silane monolayer. The ion-specific, nanoscale response of polyelectrolyte brushes was detected by using three-dimensional scanning force microscopy (3D-SFM) combined with frequency modulation detection. The obtained topographic and mechanical landscapes indicated that the brushes were uniformly stretched, undergoing a gradual transition from the brush to the bulk electrolyte in the absence of divalent cations. When 1 mM calcium ions were added, the brushes were uniformly compacted, exhibiting a sharper brush-to-bulk transition. Remarkably, the addition of 1 mM cadmium ions made the brush surface significantly rough and the mechanical landscape highly heterogeneous. Currently, cadmium-specific nanoscale compaction of the brushes is attributed to the coordination of thiol and carboxyl side chains with cadmium ions, as suggested for naturally occurring, heavy metal binding proteins.
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Affiliation(s)
- Akihisa Yamamoto
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University Kyoto 606-8501 Japan
| | - Takahiko Ikarashi
- Division of Nano Life Science, Kanazawa University Kanazawa 920-1192 Japan
| | - Takeshi Fukuma
- Division of Nano Life Science, Kanazawa University Kanazawa 920-1192 Japan
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University Kanazawa 920-1192 Japan
| | - Ryo Suzuki
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University Kyoto 606-8501 Japan
| | - Masaki Nakahata
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University Osaka 560-8531 Japan
- Department of Macromolecular Science, Graduate School of Science, Osaka University Osaka 560-0043 Japan
| | - Kazuki Miyata
- Division of Nano Life Science, Kanazawa University Kanazawa 920-1192 Japan
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University Kanazawa 920-1192 Japan
| | - Motomu Tanaka
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University Kyoto 606-8501 Japan
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, Heidelberg University 69120 Heidelberg Germany
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10
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Dyakova YA, Kovalchuk MV. Protein Self-Assembly in Crystals and Films. CRYSTALLOGR REP+ 2022. [DOI: 10.1134/s1063774522050030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Khairalla B, Brand I. Membrane Potentials Trigger Molecular-Scale Rearrangements in the Outer Membrane of Gram-Negative Bacteria. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:446-457. [PMID: 34963050 DOI: 10.1021/acs.langmuir.1c02820] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The structural complexity of the cell envelope of Gram-negative bacteria limits the fabrication of realistic models of bacterial cell membranes. A vertical Langmuir-Blodgett withdrawing was used to deposit a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) monolayer on the Au(111) surface. The second leaflet composed of di[3-deoxy-D-manno-octulosonyl]-lipid A (KLA) was deposited using Langmuir-Schaefer transfer. The use of an electrode material as a support for the POPE-KLA bilayer allowed electrochemical control of the membrane's stability, compactness, and structure. Capacitance-potential curves showed a typical pattern for the supported lipid bilayers electrochemical characteristic. The minimum membrane capacitance was ∼4 μF cm-2 and did not change in the following desorption-adsorption cycles, indicating the presence of a stable bilayer structure with an asymmetric composition of both leaflets. However, at a molecular scale, as elucidated in spectroelectrochemical experiments, large differences in the response of both leaflets to electric potentials were observed. The acyl chains in POPE and KLA existed in a liquid state. The quantitative analysis of the CH stretching modes indicated potential-driven reorientations in the hydrophobic fragment of the bilayer, already in the adsorbed state. To assign observed rearrangements to POPE and KLA lipids in both leaflets, per-deuterated d31-POPE was transferred into the inner leaflet. Since no potential-dependent changes of the CD2 stretching modes in the d31-POPE-KLA bilayer were observed, reorientations in the acyl chain region were assigned to the KLA molecules. Mg2+ ions were bound to the polar head groups of KLA. The strength of electrostatic interactions in the polar head group region of KLA was dependent on the direction of the electric field. At negative electric potentials, the binding of divalent cations weakened, which gave the KLA molecules increased orientational flexibility. This behavior in electric fields is peculiar for the outer membrane and indicates that the microbial cell membranes have different electrochemical properties than phospholipid bilayers.
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Affiliation(s)
- Bishoy Khairalla
- Department of Chemistry, University of Oldenburg, 26111 Oldenburg, Germany
| | - Izabella Brand
- Department of Chemistry, University of Oldenburg, 26111 Oldenburg, Germany
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12
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Brand I, Khairalla B. Structural changes in the model of the outer cell membrane of Gram-negative bacteria interacting with melittin: an in situ spectroelectrochemical study. Faraday Discuss 2021; 232:68-85. [PMID: 34542116 DOI: 10.1039/d0fd00039f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The cell membrane of Gram-negative bacteria interacting with an antimicrobial peptide presents a complex supramolecular assembly. Fabrication of models of bacterial cell membranes remains a large experimental challenge. Langmuir-Blodgett and Langmuir-Schaefer (LS-LB) transfer makes possible the deposition of multicomponent asymmetric lipid bilayers onto a gold surface. Two lipids: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and di[3-deoxy-D-manno-octulosonyl]-lipid A (KLA) were used to deposit a model of the outer membrane of Gram-negative bacteria on the Au(111) substrate. The use of gold as the solid substrate enables control of the membrane potential. Molecular scale changes in the model membrane exposed to physiological electric fields and interacting with melittin antimicrobial peptide are discussed in this paper. The interaction of the outer membrane with melittin leads to an increase in the membrane capacitance and permeability to ions and water. The stability of the outer membrane with bound melittin decreases at positive membrane potentials. In situ polarization modulation infrared reflection absorption spectroscopy is used to investigate membrane potential-dependent changes in the structure of the outer membrane interacting with melittin. The hydration of the ester carbonyl groups is not affected by the interaction with melittin. However, the orientation and hydrogen bond network with the carboxylate groups in KLA changes drastically after POPE-KLA bilayer interacts with melittin. We propose that the positively charged groups in the amino acids present at the C-terminus of the peptide interact directly with the polar head group of KLA. Simultaneously, the packing order in hydrocarbon chains in the membrane with bound melittin increases. A hydrophobic match between the chains in the lipids and the peptide, which spans the membrane, seems to be responsible for the ordering of the hydrocarbon chains region of the bilayer. The N-terminus enters into the hydrophobic region of the membrane and forms a channel to the hydrophilic head groups in POPE.
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Affiliation(s)
- Izabella Brand
- Department of Chemistry, University of Oldenburg, 26111 Oldenburg, Germany.
| | - Bishoy Khairalla
- Department of Chemistry, University of Oldenburg, 26111 Oldenburg, Germany.
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13
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Lee C, Dommer AC, Schiffer JM, Amaro RE, Grassian VH, Prather KA. Cation-Driven Lipopolysaccharide Morphological Changes Impact Heterogeneous Reactions of Nitric Acid with Sea Spray Aerosol Particles. J Phys Chem Lett 2021; 12:5023-5029. [PMID: 34024101 DOI: 10.1021/acs.jpclett.1c00810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Lipopolysaccharides (LPS) in sea spray aerosol (SSA) particles have recently been shown to undergo heterogeneous reactions with HNO3 in the atmosphere. Here, we integrate theory and experiment to further investigate how the most abundant sea salt cations, Na+, Mg2+, and Ca2+, impact HNO3 reactions with LPS-containing SSA particles. Aerosol reaction flow tube studies show that heterogeneous reactions of SSA particles with divalent cation (Mg2+ and Ca2+) and LPS signatures were less reactive with HNO3 than those dominated by monovalent cations (Na+). All-atom molecular dynamics simulations of model LPS aggregates suggest that divalent cations cross-link the oligosaccharide chains to increase molecular aggregation and rigidity, which changes the particle phase and morphology, decreases water diffusion, and consequently decreases the reactive uptake of HNO3. This study provides new insight into how complex chemical interactions between ocean-derived salts and biogenic organic species can impact the heterogeneous reactivity of SSA particles.
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Affiliation(s)
- Christopher Lee
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037, United States
| | - Abigail C Dommer
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Jamie M Schiffer
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Rommie E Amaro
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Vicki H Grassian
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Kimberly A Prather
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037, United States
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
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14
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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.
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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.
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15
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Rahnamoun A, Kim K, Pedersen JA, Hernandez R. Ionic Environment Affects Bacterial Lipopolysaccharide Packing and Function. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3149-3158. [PMID: 32069057 DOI: 10.1021/acs.langmuir.9b03162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The interaction of lipopolysaccharides (LPS) with metal cations strongly affects the stability and function of the Gram-negative bacterial outer membrane. The sensitivity of deep rough (Re) LPS packing and function to the ionic environment, as affected by cation valency and ionic radius, has been determined using molecular dynamics simulations and Langmuir balance experiments. The degree of LPS aggregation within the LPS models in the presence of different cations is assessed by measuring the effective mean molecular area (Âm) of each LPS molecule projected onto the interfacial plane at the end of the equilibration. These results are compared to the LPS mean molecular area from experimental measurements in which the LPS monolayers are assembled at the air-water interface using a Langmuir film balance. We found that packing of the LPS arrays is sensitive to the ionic radius and ion valency of the cations present in solution during LPS array packing. Using enhanced sampling of the free energy for the intercalation of oligo(allylamine HCl) (OAH) into deep rough Salmonella enterica LPS bilayers, we obtained the affinity of the core section of LPS to OAH as a function of the nature of the metal cations present in solution. We found that packing of the solvated LPS bilayer models is sensitive to ionic radius and ion valency of the neutralizing cations. This further suggests that ion bridging and steric barriers rather than charge shielding are important factors in mitigating ligand intercalation under conditions with low ionic concentrations.
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Affiliation(s)
- Ali Rahnamoun
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kyoungtea Kim
- Molecular and Environmental Toxicology Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Joel A Pedersen
- Molecular and Environmental Toxicology Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Departments of Soil Science, Chemistry, Civil & Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Rigoberto Hernandez
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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16
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Tanaka M. Interplays of Interfacial Forces Modulate Structure and Function of Soft and Biological Matters in Aquatic Environments. Front Chem 2020; 8:165. [PMID: 32257995 PMCID: PMC7089937 DOI: 10.3389/fchem.2020.00165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 02/25/2020] [Indexed: 11/22/2022] Open
Abstract
Water had been considered as a passive matrix that merely fills up the space, supporting the diffusion of solute molecules. In the past several decades, a number of studies have demonstrated that water play vital roles in regulating structural orders of biological systems over several orders of magnitude. Water molecules take versatile structures, many of which are transient. Water molecules act as hydrogen bond donors as well as acceptors and biochemical reactions utilize water molecules as nucleophiles. Needless to say, the same principle holds for the synthetic materials that function under water: the conformation, dynamics and functions of molecules are significantly influenced by the surrounding water. This review sheds light on how the structure and function of soft and biological matter in aquatic environments are modulated by the orchestration of various interfacial forces.
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Affiliation(s)
- Motomu Tanaka
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, Heidelberg University, Heidelberg, Germany
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto, Japan
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17
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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: 15] [Impact Index Per Article: 3.0] [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.
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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
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18
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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: 23] [Impact Index Per Article: 4.6] [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.
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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.
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19
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Plasmonic biosensors for bacterial endotoxin detection on biomimetic C-18 supported fiber optic probes. Biosens Bioelectron 2019; 129:79-86. [DOI: 10.1016/j.bios.2018.12.045] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 01/14/2023]
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20
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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.
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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.
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21
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Liquid crystalline bacterial outer membranes are critical for antibiotic susceptibility. Proc Natl Acad Sci U S A 2018; 115:E7587-E7594. [PMID: 30037998 DOI: 10.1073/pnas.1803975115] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria is a robust, impermeable, asymmetric bilayer of outer lipopolysaccharides (LPSs) and inner phospholipids containing selective pore proteins which confer on it the properties of a molecular sieve. This structure severely limits the variety of antibiotic molecules effective against Gram-negative pathogens and, as antibiotic resistance has increased, so has the need to solve the OM permeability problem. Polymyxin B (PmB) represents those rare antibiotics which act directly on the OM and which offer a distinct starting point for new antibiotic development. Here we investigate PmB's interactions with in vitro OM models and show how the physical state of the lipid matrix of the OM is a critical factor in regulating the interaction with the antimicrobial peptide. Using neutron reflectometry and infrared spectroscopy, we reveal the structural and chemical changes induced by PmB on OM models of increasing complexity. In particular, only a tightly packed model reproduced the temperature-controlled disruption of the asymmetric lipid bilayer by PmB observed in vivo. By measuring the order of outer-leaflet LPS and inner-leaflet phospholipids, we show that PmB insertion is dependent on the phase transition of LPS from the gel to the liquid crystalline state. The demonstration of a lipid phase transition in the physiological temperature range also supports the hypothesis that bacteria grown at different temperatures adapt their LPS structures to maintain a homeoviscous OM.
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22
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Micciulla S, Gerelli Y, Campbell RA, Schneck E. A Versatile Method for the Distance-Dependent Structural Characterization of Interacting Soft Interfaces by Neutron Reflectometry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:789-800. [PMID: 29039954 DOI: 10.1021/acs.langmuir.7b02971] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Interactions between soft interfaces govern the behavior of emulsions and foams and crucially influence the functions of biological entities like membranes. To understand the character of these interactions, detailed insight into the interfaces' structural response in terms of molecular arrangements and conformations is often essential. This requires the realization of controlled interaction conditions and surface-sensitive techniques capable of resolving the structure of buried interfaces. Here, we present a new approach to determine the distance-dependent structure of interacting soft interfaces by neutron reflectometry. A solid/water interface and a water/oil interface are functionalized independently and initially macroscopically separated. They are then brought into contact and structurally characterized under interacting conditions. The nanometric distance between the two interfaces can be varied via the exertion of osmotic pressures. Our first experiments on lipid-anchored polymer brushes interacting across water with solid-grafted polyelectrolyte brushes and with bare silicon surfaces reveal qualitatively different interaction scenarios depending on the chemical composition of the two involved interfaces.
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Affiliation(s)
- Samantha Micciulla
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam, Germany
- Institut Laue-Langevin , 38000 Grenoble, France
| | | | | | - Emanuel Schneck
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam, Germany
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23
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Tergolina VB, dos Santos AP. Effect of dielectric discontinuity on a spherical polyelectrolyte brush. J Chem Phys 2017; 147:114103. [DOI: 10.1063/1.5002526] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Vinicius B. Tergolina
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
| | - Alexandre P. dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970 Porto Alegre, RS, Brazil
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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24
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Liu L, Pincus PA, Hyeon C. Heterogeneous Morphology and Dynamics of Polyelectrolyte Brush Condensates in Trivalent Counterion Solution. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02685] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Lei Liu
- Korea Institute
for Advanced Study, Seoul 02455, Korea
| | - Philip A. Pincus
- Materials
and Physics Departments, University of California at Santa Barbara, Santa Barbara, California 93106, United States
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25
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Brettmann B, Pincus P, Tirrell M. Lateral Structure Formation in Polyelectrolyte Brushes Induced by Multivalent Ions. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02563] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Blair Brettmann
- The
Institute for Molecular Engineering, The University of Chicago, 5640 S. Ellis Ave., Chicago, Illinois 60637, United States
| | - Philip Pincus
- Materials
Department, Room 3004 Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Matthew Tirrell
- The
Institute for Molecular Engineering, The University of Chicago, 5640 S. Ellis Ave., Chicago, Illinois 60637, United States
- The
Institute for Molecular Engineering, Argonne National Laboratory, 9700 Cass Avenue, Lemont, Illinois 60439, United States
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26
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Dyakova YA, Marchenkova MA. Formation of partially ordered organic planar systems based on the in situ control of their structural organization. CRYSTALLOGR REP+ 2016. [DOI: 10.1134/s1063774516050060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Metabolic Fingerprinting of Pseudomonas putida DOT-T1E Strains: Understanding the Influence of Divalent Cations in Adaptation Mechanisms Following Exposure to Toluene. Metabolites 2016; 6:metabo6020014. [PMID: 27128955 PMCID: PMC4931545 DOI: 10.3390/metabo6020014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/20/2016] [Accepted: 04/21/2016] [Indexed: 11/16/2022] Open
Abstract
Pseudomonas putida strains can adapt and overcome the activity of toxic organic solvents by the employment of several resistant mechanisms including efflux pumps and modification to lipopolysaccharides (LPS) in their membranes. Divalent cations such as magnesium and calcium play a crucial role in the development of solvent tolerance in bacterial cells. Here, we have used Fourier transform infrared (FT-IR) spectroscopy directly on cells (metabolic fingerprinting) to monitor bacterial response to the absence and presence of toluene, along with the influence of divalent cations present in the growth media. Multivariate analysis of the data using principal component-discriminant function analysis (PC-DFA) showed trends in scores plots, illustrating phenotypic alterations related to the effect of Mg(2+), Ca(2+) and toluene on cultures. Inspection of PC-DFA loadings plots revealed that several IR spectral regions including lipids, proteins and polysaccharides contribute to the separation in PC-DFA space, thereby indicating large phenotypic response to toluene and these cations. Finally, the saturated fatty acid ratio from the FT-IR spectra showed that upon toluene exposure, the saturated fatty acid ratio was reduced, while it increased in the presence of divalent cations. This study clearly demonstrates that the combination of metabolic fingerprinting with appropriate chemometric analysis can result in practicable knowledge on the responses of important environmental bacteria to external stress from pollutants such as highly toxic organic solvents, and indicates that these changes are manifest in the bacterial cell membrane. Finally, we demonstrate that divalent cations improve solvent tolerance in P. putida DOT‑T1E strains.
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28
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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]
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29
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Barker RD, McKinley LE, Titmuss S. Neutron Reflectivity as a Tool for Physics-Based Studies of Model Bacterial Membranes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 915:261-82. [PMID: 27193548 DOI: 10.1007/978-3-319-32189-9_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The principles of neutron reflectivity and its application as a tool to provide structural information at the (sub-) molecular unit length scale from models for bacterial membranes are described. The model membranes can take the form of a monolayer for a single leaflet spread at the air/water interface, or bilayers of increasing complexity at the solid/liquid interface. Solid-supported bilayers constrain the bilayer to 2D but can be used to characterize interactions with antimicrobial peptides and benchmark high throughput lab-based techniques. Floating bilayers allow for membrane fluctuations, making the phase behaviour more representative of native membranes. Bilayers of varying levels of compositional accuracy can now be constructed, facilitating studies with aims that range from characterizing the fundamental physical interactions, through to the characterization of accurate mimetics for the inner and outer membranes of Gram-negative bacteria. Studies of the interactions of antimicrobial peptides with monolayer and bilayer models for the inner and outer membranes have revealed information about the molecular control of the outer membrane permeability, and the mode of interaction of antimicrobials with both inner and outer membranes.
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Affiliation(s)
- Robert D Barker
- Institut Laue-Langevin, 71 Avenue Des Martyrs, CS 20156, 38042, Grenoble Cedex 9, France.,School of Science and Engineering, University of Dundee, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Dundee, DD1 4HN, UK
| | - Laura E McKinley
- School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, Scotland
| | - Simon Titmuss
- School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, Scotland.
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30
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Structural characterization of soft interfaces by standing-wave fluorescence with X-rays and neutrons. Curr Opin Colloid Interface Sci 2015. [DOI: 10.1016/j.cocis.2015.06.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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31
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Rossetti FF, Schneck E, Fragneto G, Konovalov OV, Tanaka M. Generic Role of Polymer Supports in the Fine Adjustment of Interfacial Interactions between Solid Substrates and Model Cell Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4473-4480. [PMID: 25794040 DOI: 10.1021/la504253p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
To understand the generic role of soft, hydrated biopolymers in adjusting interfacial interactions at biological interfaces, we designed a defined model of the cell-extracellular matrix contacts based on planar lipid membranes deposited on polymer supports (polymer-supported membranes). Highly uniform polymer supports made out of regenerated cellulose allow for the control of film thickness without changing the surface roughness and without osmotic dehydration. The complementary combination of specular neutron reflectivity and high-energy specular X-ray reflectivity yields the equilibrium membrane-substrate distances, which can quantitatively be modeled by computing the interplay of van der Waals interaction, hydration repulsion, and repulsion caused by the thermal undulation of membranes. The obtained results help to understand the role of a biopolymer in the interfacial interactions of cell membranes from a physical point of view and also open a large potential to generally bridge soft, biological matter and hard inorganic materials.
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Affiliation(s)
- Fernanda F Rossetti
- †Physical Chemistry of Biosystems, Physical Chemistry Institute, University of Heidelberg, D-69120 Heidelberg, Germany
- ‡Institute for Integrated Cell-Material Sciences (WPI iCeMS), Kyoto University, 606-8501 Kyoto, Japan
| | - Emanuel Schneck
- †Physical Chemistry of Biosystems, Physical Chemistry Institute, University of Heidelberg, D-69120 Heidelberg, Germany
- §Institut Laue-Langevin (ILL), CS20156, 38042 Grenoble, France
| | | | - Oleg V Konovalov
- ∥European Synchrotron Radiation Facility (ESRF), 38042 Grenoble, France
| | - Motomu Tanaka
- †Physical Chemistry of Biosystems, Physical Chemistry Institute, University of Heidelberg, D-69120 Heidelberg, Germany
- ‡Institute for Integrated Cell-Material Sciences (WPI iCeMS), Kyoto University, 606-8501 Kyoto, Japan
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32
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Clifton LA, Skoda MA, Le Brun A, Ciesielski F, Kuzmenko I, Holt SA, Lakey JH. Effect of divalent cation removal on the structure of gram-negative bacterial outer membrane models. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 31:404-12. [PMID: 25489959 PMCID: PMC4295546 DOI: 10.1021/la504407v] [Citation(s) in RCA: 224] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/09/2014] [Indexed: 05/18/2023]
Abstract
The Gram-negative bacterial outer membrane (GNB-OM) is asymmetric in its lipid composition with a phospholipid-rich inner leaflet and an outer leaflet predominantly composed of lipopolysaccharides (LPS). LPS are polyanionic molecules, with numerous phosphate groups present in the lipid A and core oligosaccharide regions. The repulsive forces due to accumulation of the negative charges are screened and bridged by the divalent cations (Mg(2+) and Ca(2+)) that are known to be crucial for the integrity of the bacterial OM. Indeed, chelation of divalent cations is a well-established method to permeabilize Gram-negative bacteria such as Escherichia coli. Here, we use X-ray and neutron reflectivity (XRR and NR, respectively) techniques to examine the role of calcium ions in the stability of a model GNB-OM. Using XRR we show that Ca(2+) binds to the core region of the rough mutant LPS (RaLPS) films, producing more ordered structures in comparison to divalent cation free monolayers. Using recently developed solid-supported models of the GNB-OM, we study the effect of calcium removal on the asymmetry of DPPC:RaLPS bilayers. We show that without the charge screening effect of divalent cations, the LPS is forced to overcome the thermodynamically unfavorable energy barrier and flip across the hydrophobic bilayer to minimize the repulsive electrostatic forces, resulting in about 20% mixing of LPS and DPPC between the inner and outer bilayer leaflets. These results reveal for the first time the molecular details behind the well-known mechanism of outer membrane stabilization by divalent cations. This confirms the relevance of the asymmetric models for future studies of outer membrane stability and antibiotic penetration.
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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
| | - 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
| | - Anton
P. Le Brun
- Bragg
Institute, Australian Nuclear Science and
Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Filip Ciesielski
- 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
| | - Ivan Kuzmenko
- Advanced
Photon Source , Argonne National Laboratories, Argonne, Illinois 60439, United States
| | - Stephen A. Holt
- 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
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33
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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
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34
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Clifton LA, Skoda MWA, Daulton EL, Hughes AV, Le Brun AP, Lakey JH, Holt SA. Asymmetric phospholipid: lipopolysaccharide bilayers; a Gram-negative bacterial outer membrane mimic. J R Soc Interface 2013; 10:20130810. [PMID: 24132206 PMCID: PMC3808558 DOI: 10.1098/rsif.2013.0810] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 09/25/2013] [Indexed: 01/02/2023] Open
Abstract
The Gram-negative bacterial outer membrane (OM) is a complex and highly asymmetric biological barrier but the small size of bacteria has hindered advances in in vivo examination of membrane dynamics. Thus, model OMs, amenable to physical study, are important sources of data. Here, we present data from asymmetric bilayers which emulate the OM and are formed by a simple two-step approach. The bilayers were deposited on an SiO2 surface by Langmuir-Blodgett deposition of phosphatidylcholine as the inner leaflet and, via Langmuir-Schaefer deposition, an outer leaflet of either Lipid A or Escherichia coli rough lipopolysaccharides (LPS). The membranes were examined using neutron reflectometry (NR) to examine the coverage and mixing of lipids between the bilayer leaflets. NR data showed that in all cases, the initial deposition asymmetry was mostly maintained for more than 16 h. This stability enabled the sizes of the headgroups and bilayer roughness of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and Lipid A, Rc-LPS and Ra-LPS to be clearly resolved. The results show that rough LPS can be manipulated like phospholipids and used to fabricate advanced asymmetric bacterial membrane models using well-known bilayer deposition techniques. Such models will enable OM dynamics and interactions to be studied under in vivo-like conditions.
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Affiliation(s)
- Luke A. Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
| | - Maximilian W. A. Skoda
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
| | - Emma L. Daulton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
- Department of Chemistry, University of Bath, Bath BA2 7AY, UK
| | - Arwel V. Hughes
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
| | - Anton P. Le Brun
- 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, UK
| | - Stephen A. Holt
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
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35
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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.
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Affiliation(s)
- A Pustam
- Chemistry Department, St Francis Xavier University, Antigonish, NS, Canada; Centre for Biofouling Research, St Francis Xavier University, Antigonish, NS, Canada
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36
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Importance of lipopolysaccharide aggregate disruption for the anti-endotoxic effects of heparin cofactor II peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2709-19. [DOI: 10.1016/j.bbamem.2013.06.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 06/12/2013] [Accepted: 06/14/2013] [Indexed: 11/21/2022]
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37
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38
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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.
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Affiliation(s)
- Wasim Abuillan
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, D69120 Heidelberg, Germany
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39
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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.
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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
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40
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Singh S, Kalle M, Papareddy P, Schmidtchen A, Malmsten M. Lipopolysaccharide Interactions of C-Terminal Peptides from Human Thrombin. Biomacromolecules 2013; 14:1482-92. [DOI: 10.1021/bm400150c] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Shalini Singh
- Department of Pharmacy, Uppsala University, SE-75123, Uppsala,
Sweden
| | - Martina Kalle
- Division of Dermatology
and
Venereology, Department of Clinical Sciences, Lund University, SE-221 84 Lund, Sweden
| | - Praveen Papareddy
- Division of Dermatology
and
Venereology, Department of Clinical Sciences, Lund University, SE-221 84 Lund, Sweden
| | - Artur Schmidtchen
- Division of Dermatology
and
Venereology, Department of Clinical Sciences, Lund University, SE-221 84 Lund, Sweden
| | - Martin Malmsten
- Department of Pharmacy, Uppsala University, SE-75123, Uppsala,
Sweden
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41
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Schneck E, Jentschel M, Gege C, Tanaka M, Demé B. Grazing-incidence neutron-induced fluorescence probes density profiles of labeled molecules at solid/liquid interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:4084-4091. [PMID: 23461763 DOI: 10.1021/la400162y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report on the use of characteristic prompt γ-fluorescence after neutron capture induced by an evanescent neutron wave to probe densities and depth profiles of labeled molecules at solid/liquid interfaces. In contrast to classical scattering techniques and X-ray fluorescence, this method of "grazing-incidence neutron-induced fluorescence" combines direct chemical specificity, provided by the label, with sensitivity to the interface, inherent to the evanescent wave. We demonstrate that the formation of a supported lipid membrane can be quantitatively monitored from the characteristic fluorescence of (157)Gd(3+) ions bound to the headgroup of chelator lipids. Moreover, we were able to localize the (157)Gd(3+) ions along the surface normal with nanometer precision. This first proof of principle with a well-defined model system suggests that the method has a great potential for biology and soft matter studies where spatial resolution and chemical sensitivity are required.
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Affiliation(s)
- Emanuel Schneck
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, Heidelberg, Germany.
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42
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Singh S, Kasetty G, Schmidtchen A, Malmsten M. Membrane and lipopolysaccharide interactions of C-terminal peptides from S1 peptidases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2244-51. [DOI: 10.1016/j.bbamem.2012.03.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 03/23/2012] [Accepted: 03/26/2012] [Indexed: 11/30/2022]
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43
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French S, Puddephatt D, Habash M, Glasauer S. The dynamic nature of bacterial surfaces: Implications for metal–membrane interaction. Crit Rev Microbiol 2012; 39:196-217. [DOI: 10.3109/1040841x.2012.702098] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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44
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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.
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Affiliation(s)
- David B Alexander
- Laboratory of Nanotoxicology Project, Nagoya City University, 3-1 Tanabedohri, Mizuho-ku, Nagoya 467-8603, Japan.
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45
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Kabanov DS, Prokhorenko IR. Structural analysis of lipopolysaccharides from Gram-negative bacteria. BIOCHEMISTRY (MOSCOW) 2010; 75:383-404. [PMID: 20618127 DOI: 10.1134/s0006297910040012] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This review covers data on composition and structure of lipid A, core, and O-polysaccharide of the known lipopolysaccharides from Gram-negative bacteria. The relationship between the structure and biological activity of lipid A is discussed. The data on roles of core and O-polysaccharide in biological activities of lipopolysaccharides are presented. The structural homology of some oligosaccharide sequences of lipopolysaccharides to gangliosides of human cell membranes is considered.
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Affiliation(s)
- D S Kabanov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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46
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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.
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47
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Zaccai G. Biological physics at large facilities: from molecule to cell. J R Soc Interface 2009; 6 Suppl 5:S565-6. [PMID: 19640878 DOI: 10.1098/rsif.2009.0269.focus] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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