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Caselli L, Parra-Ortiz E, Micciulla S, Skoda MWA, Häffner SM, Nielsen EM, van der Plas MJA, Malmsten M. Boosting Membrane Interactions and Antimicrobial Effects of Photocatalytic Titanium Dioxide Nanoparticles by Peptide Coating. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2309496. [PMID: 38402437 DOI: 10.1002/smll.202309496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/30/2024] [Indexed: 02/26/2024]
Abstract
Photocatalytic nanoparticles offer antimicrobial effects under illumination due to the formation of reactive oxygen species (ROS), capable of degrading bacterial membranes. ROS may, however, also degrade human cell membranes and trigger toxicity. Since antimicrobial peptides (AMPs) may display excellent selectivity between human cells and bacteria, these may offer opportunities to effectively "target" nanoparticles to bacterial membranes for increased selectivity. Investigating this, photocatalytic TiO2 nanoparticles (NPs) are coated with the AMP LL-37, and ROS generation is found by C11-BODIPY to be essentially unaffected after AMP coating. Furthermore, peptide-coated TiO2 NPs retain their positive ζ-potential also after 1-2 h of UV illumination, showing peptide degradation to be sufficiently limited to allow peptide-mediated targeting. In line with this, quartz crystal microbalance measurements show peptide coating to promote membrane binding of TiO2 NPs, particularly so for bacteria-like anionic and cholesterol-void membranes. As a result, membrane degradation during illumination is strongly promoted for such membranes, but not so for mammalian-like membranes. The mechanisms of these effects are elucidated by neutron reflectometry. Analogously, LL-37 coating promoted membrane rupture by TiO2 NPs for Gram-negative and Gram-positive bacteria, but not for human monocytes. These findings demonstrate that AMP coating may selectively boost the antimicrobial effects of photocatalytic NPs.
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Affiliation(s)
- Lucrezia Caselli
- Department of Pharmacy, University of Copenhagen, Copenhagen, DK-2100, Denmark
- Department of Physical Chemistry 1, Lund University, Lund, SE-22100, Sweden
| | - Elisa Parra-Ortiz
- Department of Pharmacy, University of Copenhagen, Copenhagen, DK-2100, Denmark
- Novonesis, Biologiens Vej 2, Lyngby, DK-2800 Kgs, Denmark
| | - Samantha Micciulla
- Institut Laue-Langevin, CS 20156, Grenoble Cedex 9, 38042, France
- Laboratoire Interdisciplinaire de Physique (LIPhy), Saint Martin d'Hères, 38402, France
- Centre National de la Recherche Scientifique (CNRS), Saint-Martin-d'Hères, Auvergne-Rhône-Alpes, France
| | - Maximilian W A Skoda
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, OX11 0QX, UK
| | - Sara Malekkhaiat Häffner
- Department of Pharmacy, University of Copenhagen, Copenhagen, DK-2100, Denmark
- RISE Research Institutes of Sweden, Malvinas väg 3, Stockholm, 114 86, Sweden
| | | | | | - Martin Malmsten
- Department of Pharmacy, University of Copenhagen, Copenhagen, DK-2100, Denmark
- Department of Physical Chemistry 1, Lund University, Lund, SE-22100, Sweden
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Caselli L, Köhler S, Schirone D, Humphreys B, Malmsten M. Conformational control of antimicrobial peptide amphiphilicity: consequences for boosting membrane interactions and antimicrobial effects of photocatalytic TiO 2 nanoparticles. Phys Chem Chem Phys 2024; 26:16529-16539. [PMID: 38828872 DOI: 10.1039/d4cp01724b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
This study reports on the effects of conformationally controlled amphiphilicity of antimicrobial peptides (AMPs) on their ability to coat TiO2 nanoparticles (NPs) and boost the photocatalytic antimicrobial effects of such NPs. For this, TiO2 NPs were combined with AMP EFK17 (EFKRIVQRIKDFLRNLV), displaying a disordered conformation in aqueous solution but helix formation on interaction with bacterial membranes. The membrane-bound helix is amphiphilic, with all polar and charged amino acid residues located at one side and all non-polar and hydrophobic residues on the other. In contrast, the d-enantiomer variant EFK17-d (E(dF)KR(dI)VQR(dI)KD(dF)LRNLV) is unable to form the amphiphilic helix on bacterial membrane interaction, whereas the W-residues in EFK17-W (EWKRWVQRWKDFLRNLV) boost hydrophobic interactions of the amphiphilic helix. Circular dichroism results showed the effects displayed for the free peptide, to also be present for peptide-coated TiO2 NPs, causing peptide binding to decrease in the order EFK17-W > EFK17 > EFK17-d. Notably, the formation of reactive oxygen species (ROS) by the TiO2 NPs was essentially unaffected by the presence of peptide coating, for all the peptides investigated, and the coatings stabilized over hours of UV exposure. Photocatalytic membrane degradation from TiO2 NPs coated with EFK17-W and EFK17 was promoted for bacteria-like model bilayers containing anionic phosphatidylglycerol but suppressed in mammalian-like bilayers formed by zwitterionic phosphatidylcholine and cholesterol. Structural aspects of these effects were further investigated by neutron reflectometry with clear variations observed between the bacteria- and mammalian-like model bilayers for the three peptides. Mirroring these results in bacteria-like model membranes, combining TiO2 NPs with EFK17-W and EFK17, but not with non-adsorbing EFK17-d, resulted in boosted antimicrobial effects of the resulting cationic composite NPs already in darkness, effects enhanced further on UV illumination.
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Affiliation(s)
- Lucrezia Caselli
- Department of Physical Chemistry 1, Lund University, SE-22100 Lund, Sweden.
| | - Sebastian Köhler
- LINXS Institute of Advanced Neutron and X-ray Science, Scheelevagen 19, 22370 Lund, Sweden
| | - Davide Schirone
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Malmö University, 20506 Malmö, Sweden
| | - Ben Humphreys
- Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France
| | - Martin Malmsten
- Department of Physical Chemistry 1, Lund University, SE-22100 Lund, Sweden.
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark
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Effects of a Semisynthetic Catechin on Phosphatidylglycerol Membranes: A Mixed Experimental and Simulation Study. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28010422. [PMID: 36615630 PMCID: PMC9824143 DOI: 10.3390/molecules28010422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/27/2022] [Accepted: 12/30/2022] [Indexed: 01/06/2023]
Abstract
Catechins have been shown to display a great variety of biological activities, prominent among them are their chemo preventive and chemotherapeutic properties against several types of cancer. The amphiphilic nature of catechins points to the membrane as a potential target for their actions. 3,4,5-Trimethoxybenzoate of catechin (TMBC) is a modified structural analog of catechin that shows significant antiproliferative activity against melanoma and breast cancer cells. Phosphatidylglycerol is an anionic membrane phospholipid with important physical and biochemical characteristics that make it biologically relevant. In addition, phosphatidylglycerol is a preeminent component of bacterial membranes. Using biomimetic membranes, we examined the effects of TMBC on the structural and dynamic properties of phosphatidylglycerol bilayers by means of biophysical techniques such as differential scanning calorimetry, X-ray diffraction and infrared spectroscopy, together with an analysis through molecular dynamics simulation. We found that TMBC perturbs the thermotropic gel to liquid-crystalline phase transition and promotes immiscibility in both phospholipid phases. The modified catechin decreases the thickness of the bilayer and is able to form hydrogen bonds with the carbonyl groups of the phospholipid. Experimental data support the simulated data that locate TMBC as mostly forming clusters in the middle region of each monolayer approaching the carbonyl moiety of the phospholipid. The presence of TMBC modifies the structural and dynamic properties of the phosphatidylglycerol bilayer. The decrease in membrane thickness and the change of the hydrogen bonding pattern in the interfacial region of the bilayer elicited by the catechin might contribute to the alteration of the events taking place in the membrane and might help to understand the mechanism of action of the diverse effects displayed by catechins.
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Parra-Ortiz E, Caselli L, Agnoletti M, Skoda MWA, Li X, Zhao D, Malmsten M. Mesoporous silica as a matrix for photocatalytic titanium dioxide nanoparticles: lipid membrane interactions. NANOSCALE 2022; 14:12297-12312. [PMID: 35960150 DOI: 10.1039/d2nr01958b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In the present study, we investigate the combined interaction of mesoporous silica (SiO2) and photocatalytic titanium dioxide (TiO2) nanoparticles with lipid membranes, using neutron reflectometry (NR), cryo-transmission electron microscopy (cryo-TEM), fluorescence oxidation assays, dynamic light scattering (DLS), and ζ-potential measurements. Based on DLS, TiO2 nanoparticles were found to display strongly improved colloidal stability at physiological pH of skin (pH 5.4) after incorporation into either smooth or spiky ("virus-like") mesoporous silica nanoparticles at low pH, the latter demonstrated by cryo-TEM. At the same time, such matrix-bound TiO2 nanoparticles retain their ability to destabilize anionic bacteria-mimicking lipid membranes under UV-illumination. Quenching experiments indicated both hydroxyl and superoxide radicals to contribute to this, while NR showed that free TiO2 nanoparticles and TiO2 loaded into mesoporous silica nanoparticles induced comparable effects on supported lipid membranes, including membrane thinning, lipid removal, and formation of a partially disordered outer membrane leaflet. By comparing effects for smooth and virus-like mesoporous nanoparticles as matrices for TiO2 nanoparticles, the interplay between photocatalytic and direct membrane binding effects were elucidated. Taken together, the study outlines how photocatalytic nanoparticles can be readily incorporated into mesoporous silica nanoparticles for increased colloidal stability and yet retain most of their capacity for photocatalytic destabilization of lipid membranes, and with maintained mechanisms for oxidative membrane destabilization. As such, the study provides new mechanistic information to the widely employed, but poorly understood, practice of loading photocatalytic nanomaterials onto/into matrix materials for increased performance.
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Affiliation(s)
- Elisa Parra-Ortiz
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark.
| | - Lucrezia Caselli
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark.
| | - Monica Agnoletti
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark.
| | - Maximilian W A Skoda
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, OX11 0QX Harwell, Oxfordshire, UK
| | - Xiaomin Li
- Department of Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, 200433 Shanghai, P. R. China
| | - Dongyuan Zhao
- Department of Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, 200433 Shanghai, P. R. China
| | - Martin Malmsten
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark.
- Department of Physical Chemistry 1, University of Lund, SE-22100 Lund, Sweden
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Joodaki F, Martin LM, Greenfield ML. Generation and Computational Characterization of a Complex Staphylococcus aureus Lipid Bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:9481-9499. [PMID: 35901279 DOI: 10.1021/acs.langmuir.2c00483] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Studies indicate a crucial cell membrane role in the antibiotic resistance of Staphylococcus aureus. To simulate its membrane structure and dynamics, a complex molecular-scale computational representation of the S. aureus lipid bilayer was developed. Phospholipid types and their amounts were optimized by reverse Monte Carlo to represent characterization data from the literature, leading to 19 different phospholipid types that combine three headgroups [phosphatidylglycerol, lysyl-phosphatidylglycerol (LPG), and cardiolipin] and 10 tails, including iso- and anteiso-branched saturated chains. The averaged lipid bilayer thickness was 36.7 Å, and area per headgroup was 67.8 Å2. Phosphorus and nitrogen density profiles showed that LPG headgroups tended to be bent and oriented more parallel to the bilayer plane. The water density profile showed that small amounts reached the membrane center. Carbon density profiles indicated hydrophobic interactions for all lipids in the middle of the bilayer. Bond vector order parameters along each tail demonstrated different C-H ordering even within distinct lipids of the same type; however, all tails followed similar trends in average order parameter. These complex simulations further revealed bilayer insights beyond those attainable with monodisperse, unbranched lipids. Longer tails often extended into the opposite leaflet. Carbon at and beyond a branch showed significantly decreased ordering compared to carbon in unbranched tails; this feature arose in every branched lipid. Diverse tail lengths distributed these disordered methyl groups throughout the middle third of the bilayer. Distributions in mobility and ordering reveal diverse properties that cannot be obtained with monodisperse lipids.
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Affiliation(s)
- Faramarz Joodaki
- Department of Chemical Engineering, University of Rhode Island, 360 Fascitelli Center for Advanced Engineering, Kingston, Rhode Island 02881, United States
| | - Lenore M Martin
- Department of Cell and Molecular Biology, University of Rhode Island, 120 Flagg Road, Kingston, Rhode Island 02881, United States
| | - Michael L Greenfield
- Department of Chemical Engineering, University of Rhode Island, 360 Fascitelli Center for Advanced Engineering, Kingston, Rhode Island 02881, United States
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van Aalst EJ, Borcik CG, Wylie BJ. Spectroscopic signatures of bilayer ordering in native biological membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183891. [PMID: 35217001 PMCID: PMC10793244 DOI: 10.1016/j.bbamem.2022.183891] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 06/14/2023]
Abstract
Membrane proteins and polycyclic lipids like cholesterol and hopanoids coordinate phospholipid bilayer ordering. This phenomenon manifests as partitioning of the liquid crystalline phase into liquid-ordered (Lo) and liquid-disordered (Ld) regions. In Eukaryotes, microdomains are rich in cholesterol and sphingolipids and serve as signal transduction scaffolds. In Prokaryotes, Lo microdomains increase pathogenicity and antimicrobial resistance. Previously, we identified spectroscopically distinct chemical shift signatures for all-trans (AT) and trans-gauche (TG) acyl chain conformations, cyclopropyl ring lipids (CPR), and hopanoids in prokaryotic lipid extracts and used Polarization Transfer (PT) SSNMR to investigate bilayer ordering. To investigate how these findings relate to native bilayer organization, we interrogate whole cell and whole membrane extract samples of Burkholderia thailendensis to investigate bilayer ordering in situ. In 13C-13C 2D SSNMR spectra, we assigned chemical shifts for lipid species in both samples, showing conservation of lipids of interest in our native membrane sample. A one-dimensional temperature series of PT SSNMR and transverse relaxation measurements of AT versus TG acyl conformations in the membrane sample confirm bilayer ordering and a broadened phase transition centered at a lower-than-expected temperature. Bulk protein backbone Cα dynamics and correlations consistent with lipid-protein contacts within are further indicative of microdomain formation and lipid ordering. In aggregate, these findings provide evidence for microdomain formation in vivo and provide insight into phase separation and transition mechanics in biological membranes.
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Affiliation(s)
- Evan J van Aalst
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79415, USA
| | - Collin G Borcik
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79415, USA
| | - Benjamin J Wylie
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79415, USA.
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Gupta R, Sharma VK, Gupta J, Ghosh SK. 1,3 Dialkylated Imidazolium Ionic Liquid Causes Interdigitated Domains in a Phospholipid Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:3412-3421. [PMID: 35263113 DOI: 10.1021/acs.langmuir.1c03160] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Amphiphilic imidazolium-based ionic liquids (ILs) have proven their efficacy in altering the membrane integrity and dynamics. The present article investigates the phase-separated domains in a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) membrane induced by 1,3 dialkylated imidazolium IL. Isotherm measurements on DPPC monolayers formed at the air-water interface have shown a decrease in the mean molecular area with the addition of this IL. The positive value of the excess Gibbs free energy of mixing indicates an unfavorable mixing of the IL into the lipid. This leads to IL-induced phase-separated domains in the multilayer of the lipid confirmed by the occurrence of two sets of equidistance peaks in the X-ray reflectivity data. The electron density profile along the surface normal obtained by the swelling method shows the bilayer thickness of the newly formed IL-rich phase to be substantially lower (∼34 Å) than the DPPC phase (∼45.8 Å). This IL-rich phase has been confirmed to be interdigitated, showing an enhanced electron density in the tail region due to the overlapping hydrocarbon chains. Differential scanning calorimetry measurements showed that the incorporation of IL enhances the fluidity of the lipid bilayer. Therefore, the study indicates the formation of an interdigitated phase with a lower order compared to the gel phase in the DPPC membrane supplemented with the IL.
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Affiliation(s)
- Ritika Gupta
- Department of Physics, School of Natural Sciences, Shiv Nadar University, NH 91, Tehsil Dadri, G. B. Nagar, Greater Noida, Uttar Pradesh 201314, India
| | - Veerendra K Sharma
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Jyoti Gupta
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Sajal K Ghosh
- Department of Physics, School of Natural Sciences, Shiv Nadar University, NH 91, Tehsil Dadri, G. B. Nagar, Greater Noida, Uttar Pradesh 201314, India
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Häffner SM, Parra-Ortiz E, Browning KL, Jørgensen E, Skoda MWA, Montis C, Li X, Berti D, Zhao D, Malmsten M. Membrane Interactions of Virus-like Mesoporous Silica Nanoparticles. ACS NANO 2021; 15:6787-6800. [PMID: 33724786 DOI: 10.1021/acsnano.0c10378] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In the present study, we investigated lipid membrane interactions of silica nanoparticles as carriers for the antimicrobial peptide LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES). In doing so, smooth mesoporous nanoparticles were compared to virus-like mesoporous nanoparticles, characterized by a "spiky" external surface, as well as to nonporous silica nanoparticles. For this, we employed a combination of neutron reflectometry, ellipsometry, dynamic light scattering, and ζ-potential measurements for studies of bacteria-mimicking bilayers formed by palmitoyloleoylphosphatidylcholine/palmitoyloleoylphosphatidylglycerol. The results show that nanoparticle topography strongly influences membrane binding and destabilization. We found that virus-like particles are able to destabilize such lipid membranes, whereas the corresponding smooth silica nanoparticles are not. This effect of particle spikes becomes further accentuated after loading of such particles with LL-37. Thus, peptide-loaded virus-like nanoparticles displayed more pronounced membrane disruption than either peptide-loaded smooth nanoparticles or free LL-37. The structural basis of this was clarified by neutron reflectometry, demonstrating that the virus-like nanoparticles induce trans-membrane defects and promote incorporation of LL-37 throughout both bilayer leaflets. The relevance of such effects of particle spikes for bacterial membrane rupture was further demonstrated by confocal microscopy and live/dead assays on Escherichia coli bacteria. Taken together, these findings demonstrate that topography influences the interaction of nanoparticles with bacteria-mimicking lipid bilayers, both in the absence and presence of antimicrobial peptides, as well as with bacteria. The results also identify virus-like mesoporous nanoparticles as being of interest in the design of nanoparticles as delivery systems for antimicrobial peptides.
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Affiliation(s)
| | - Elisa Parra-Ortiz
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Kathryn L Browning
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Elin Jørgensen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Maximilian W A Skoda
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 0QX, United Kingdom
| | - Costanza Montis
- CSGI and Department of Chemistry "Ugo Schiff″, University of Florence, IT-50019 Sesto Fiorentino, Italy
| | - Xiaomin Li
- Department of Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433, People's Republic of China
| | - Debora Berti
- CSGI and Department of Chemistry "Ugo Schiff″, University of Florence, IT-50019 Sesto Fiorentino, Italy
| | - Dongyuan Zhao
- Department of Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433, People's Republic of China
| | - Martin Malmsten
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark
- Department of Physical Chemistry 1, University of Lund, SE-22100 Lund, Sweden
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Malekkhaiat Häffner S, Parra-Ortiz E, Skoda MWA, Saerbeck T, Browning KL, Malmsten M. Composition effects on photooxidative membrane destabilization by TiO 2 nanoparticles. J Colloid Interface Sci 2021; 584:19-33. [PMID: 33039680 DOI: 10.1016/j.jcis.2020.09.046] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/11/2020] [Accepted: 09/12/2020] [Indexed: 11/30/2022]
Abstract
Membrane interactions and photooxidative membrane destabilization of titanium dioxide (TiO2) nanoparticles were investigated, focusing on the effects of membrane composition, notably phospholipid headgroup charge and presence of cholesterol. For this, we employed a battery of state-of-the-art methods for studies of bilayers formed by zwitterionic palmitoyloleoylphosphatidylcholine (POPC) containing also polyunsaturated palmitoylarachidonoylphosphocholine (PAPC), as well as its mixtures with anionic palmitoyloleoylphosphatidylglycerol (POPG) and cholesterol. It was found that the TiO2 nanoparticles display close to zero charge at pH 7.4, resulting in aggregation. At pH 3.4, in contrast, the 6 nm TiO2 nanoparticles are well dispersed due to a strongly positive ζ-potential. Mirroring this pH dependence, TiO2 nanoparticles were observed to bind to negatively charged lipid bilayers at pH 3.4, but much less so at pH 7.4. While nanoparticle binding has some destabilizing effect alone, illumination with ultraviolet (UV) light accentuates membrane destabilization, a result of oxidative stress caused by generated reactive oxygen species (ROS). Neutron reflectivity (NR), quartz crystal microbalance (QCM), and small-angle X-ray scattering (SAXS) results all demonstrate that membrane composition strongly influences membrane interactions and photooxidative destabilization of lipid bilayers. In particular, the presence of anionic POPG makes the bilayers more sensitive to oxidative destabilization, whereas a stabilizing effect was observed in the presence of cholesterol. Also, structural aspects of peroxidation were found to depend strongly on membrane composition, notably the presence of anionic phospholipids. The results show that membrane interactions and UV-induced ROS generation act in concert and need to be considered together to understand effects of lipid membrane composition on UV-triggered oxidative destabilization by TiO2 nanoparticles, e.g., in the context of oxidative damage of bacteria and cells.
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Affiliation(s)
| | - E Parra-Ortiz
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - M W A Skoda
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
| | - T Saerbeck
- Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France
| | - K L Browning
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - M Malmsten
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark; Department of Physical Chemistry 1, University of Lund, SE-22100 Lund, Sweden
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Denk P, El Maangar A, Lal J, Kleber D, Zemb T, Kunz W. Phase diagrams and microstructures of aqueous short alkyl chain polyethylene glycol ether carboxylate and carboxylic acid triblock surfactant solutions. J Colloid Interface Sci 2021; 590:375-386. [PMID: 33556757 DOI: 10.1016/j.jcis.2021.01.061] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 11/15/2022]
Abstract
HYPOTHESIS The surfactant C8EO8CH2COOH (Akypo LF2) and its salts have a small hydrophobic and a significantly longer hydrophilic part. As a consequence, there must be a significant steric constraint, once these surfactant molecules form micelles. In addition, the partially charged headgroups should bring some additional fine-tuning via electrostatic interactions to this "essentially non-ionic" surfactant. EXPERIMENTS Phase diagrams of binary mixtures of water and C8EO8CH2COOH are established over large concentration and temperature ranges, also at different pHs and in the presence of sodium and calcium ions. Surface tensions and osmotic pressures are measured to understand the systems. To evaluate the microstructures, also Dynamic Light Scattering and Small-Angle X-ray Scattering are performed. FINDINGS Apart from the formation of coacervates at very low surfactant concentrations, spherical micelles persist over the whole concentration and temperature range and do not change in size and shape. At very high surfactant concentrations, above 60% by weight, where the headgroups are no longer fully hydrated, the standard core-shell structure of micelles vanishes and highly stabilized aggregates of 8-26 octyl chains are suspended in interdigitated polyoxyethylene layers and form an "osmotic brush". When the acid is partially transformed to a sodium salt, the repulsion between the micelles increases, whereas bridging between micelles prevails, when the counterions are calcium cations. Remarkably, the negative charges of the headgroups are randomly distributed in the hydrophilic ethylene oxide shell. Altogether, a phase diagram without lyotropic liquid crystalline phases and an extreme shift of the cloud-point in temperature and composition is found, similar to the phase diagram of C8EO8OH already known in literature. The phase properties can be explained by the curvature and packing constraints together with the Lindemann rule applied to short hydrocarbon chains.
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Affiliation(s)
- Patrick Denk
- Institute of Physical and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, D-93040 Regensburg, Germany
| | | | - Jyotsana Lal
- Institute of Physical and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, D-93040 Regensburg, Germany; Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA; Department of Physics, Northern Illinois University, DeKalb, IL 60115, USA
| | - David Kleber
- Institute of Physical and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, D-93040 Regensburg, Germany
| | - Thomas Zemb
- ICSM, Univ. Montpellier, CEA, CNRS, ENSCM, Marcoule, France
| | - Werner Kunz
- Institute of Physical and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, D-93040 Regensburg, Germany.
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Oseliero Filho PL, Gerbelli BB, Fornasier F, Chaves Filho AB, Yoshinaga MY, Miyamoto S, Mortara L, Lacerda CD, Cuccovia IM, Pimentel AS, Oliveira CLP. Structure and Thermotropic Behavior of Bovine- and Porcine-Derived Exogenous Lung Surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:14514-14529. [PMID: 33210931 DOI: 10.1021/acs.langmuir.0c02224] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two commercial exogenous pulmonary surfactants, Curosurf and Survanta, are investigated. Their thermotropic behavior and associated structural changes for the samples in bulk are characterized and described. For Survanta, the obtained results of differential scanning calorimetry showed a thermogram with three peaks on heating and only a single peak on cooling. Curosurf on the other hand, presents calorimetric thermograms with only one peak in both the heating and cooling scans. This distinct thermotropic behavior between the two pulmonary surfactants, a consequence of their particular compositions, is associated with structural changes that were evaluated by simultaneous small- and wide-angle X-ray scattering experiments with in situ temperature variation. Interestingly, for temperatures below ∼35 °C for Curosurf and ∼53 °C for Survanta, the scattering data indicated the coexistence of two lamellar phases with different carbon chain organizations. For temperatures above these limits, the coexistence of phases disappears, giving rise to a fluid phase in both pulmonary surfactants, with multilamelar vesicles for Curosurf and unilamellar vesicles for Survanta. This process is quasi-reversible under cooling, and advanced data analysis for the scattering data indicated differences in the structural and elastic properties of the pulmonary surfactants. The detailed and systematic investigation shown in this work expands on the knowledge of the structure and thermodynamic behavior of Curosurf and Survanta, being relevant from both physiological and biophysical perspectives and also providing a basis for further studies on other types of pulmonary surfactants.
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Affiliation(s)
| | - Barbara Bianca Gerbelli
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP 09210-580, Brazil
| | - Franccesca Fornasier
- Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, RJ 22453-900, Brazil
| | - Adriano B Chaves Filho
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Marcos Yukio Yoshinaga
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Sayuri Miyamoto
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Laura Mortara
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Caroline Dutra Lacerda
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - Iolanda Midea Cuccovia
- Instituto de Química, Universidade de São Paulo, Avenida Prof. Lineu Prestes, Butantã, São Paulo, SP 05508-000, Brazil
| | - André Silva Pimentel
- Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, RJ 22453-900, Brazil
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12
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Genova J, Chamati H, Petrov M. Study of SOPC with embedded pristine and amide-functionalized single wall carbon nanotubes by DSC and FTIR spectroscopy. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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13
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Sani MA, Le Brun AP, Separovic F. The antimicrobial peptide maculatin self assembles in parallel to form a pore in phospholipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183204. [DOI: 10.1016/j.bbamem.2020.183204] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/15/2019] [Accepted: 01/21/2020] [Indexed: 01/06/2023]
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14
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Reiter R, Zaitseva E, Baaken G, Halimeh I, Behrends JC, Zumbuehl A. Activity of the Gramicidin A Ion Channel in a Lipid Membrane with Switchable Physical Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14959-14966. [PMID: 31645105 DOI: 10.1021/acs.langmuir.9b02752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lipid bilayer membranes formed from the artificial 1,3-diamidophospholipid Pad-PC-Pad have the remarkable property that their hydrophobic thickness can be modified in situ: the particular arrangement of the fatty acid chains in Pad-PC-Pad allows them to fully interdigitate below 37 °C, substantially thinning the membrane with respect to the noninterdigitated state. Two stimuli, traversing the main phase transition temperature of the lipid or addition of cholesterol, have previously been shown to disable the interdigitated state. Both manipulations cause an increase in hydrophobic thickness of about 25 Å due to enhanced conformational entropy of the lipids. Here, we characterize the interdigitated state using electrophysiological recordings from free-standing lipid-membranes formed on micro structured electrode cavity arrays. Compared to standard membranes made from 1,2-diphytanoyl-sn-glycero-3-phosphocholin (DPhPC), pure Pad-PC-Pad membranes at room temperature had lowered electroporation threshold and higher capacitance. Ion channel formation by the peptide Gramicidin A was clearly facilitated in pure Pad-PC-Pad membranes at room temperature, with activity occurring at significantly lower peptide concentrations and channel dwell times increased by 2 orders of magnitude with respect to DPhPC-membranes. Both elevation of temperature beyond the phase transition and addition of cholesterol reduced channel dwell times, as expected if the reduced membrane thickness stabilized channel formation due to decreased hydrophobic mismatch.
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Affiliation(s)
- Renate Reiter
- Institute of Physics , University of Freiburg , Hermann-Herder-Strasse 3 , 79104 , Freiburg , Germany
- Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT) , 79110 , Freiburg , Germany
| | - Ekaterina Zaitseva
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine , University of Freiburg , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
- Ionera Technologies GmbH , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
| | - Gerhard Baaken
- Ionera Technologies GmbH , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
| | - Ibrahim Halimeh
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine , University of Freiburg , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
- Ionera Technologies GmbH , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
| | - Jan C Behrends
- Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT) , 79110 , Freiburg , Germany
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine , University of Freiburg , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
- Freiburg Centre for Materials Research , (FMF) Stefan Meier Strasse 21 , 79104 , Freiburg , Germany
| | - Andreas Zumbuehl
- National Center of Competence in Research in Chemical Biology , Geneva CH-1211 , Switzerland
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15
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Sosa Morales MC, Juárez AC, Montich GG, Álvarez RMS. Interaction of the antibiotic peptide nisin with anionic membranes in different phase-states: a vibrational study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 215:389-397. [PMID: 30856583 DOI: 10.1016/j.saa.2019.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 02/20/2019] [Accepted: 03/04/2019] [Indexed: 06/09/2023]
Abstract
Interactions between the antibiotic peptide nisin and multilamellar vesicles of phosphoglycerol lipids in different phase-states were studied using vibrational spectroscopy. The infrared amide I' band of nisin, both in solution and in the membrane-bound state, was analyzed in the temperature range comprised between 20 and 60 °C in order to study its conformational behavior. Nisin presented mainly unordered and β-turns conformations. Their relative populations varied according to the environment and as the temperature increased: β turns were more favored in the membrane-bound state than in solution, but at higher temperatures the disordered conformation was dominant in both states. Spectral changes of specific infrared bands belonging to the hydrocarbon and polar moieties of lipids were also analyzed to evaluate the perturbation of the lipid membrane order. Nisin interactions with the membrane polar region induced a high restriction to water incorporation, promoting a small increase in the temperature of the lipid phase transition. Raman spectra of nisin/phosphoglycerol systems at ambient temperature were also analyzed. They revealed that the peptide incorporation to a membrane in the fluid phase caused drastic structural modifications in the hydrophobic region of the bilayer. Although nisin may be able to disrupt the hydrophobic portion of the bilayer in the gel phase, the most of the peptide molecule remained at the membrane surface interacting with the polar headgroups. This work provides evidence of a differential effect of nisin on anionic membranes, depending on the phase-state of the lipid.
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Affiliation(s)
- Marcelo C Sosa Morales
- Instituto de Química del Noroeste Argentino (INQUINOA), Universidad Nacional de Tucumán, CONICET, San Miguel de Tucumán, Argentina
| | - Ana C Juárez
- Instituto de Química del Noroeste Argentino (INQUINOA), Universidad Nacional de Tucumán, CONICET, San Miguel de Tucumán, Argentina
| | - Guillermo G Montich
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina; Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Rosa M S Álvarez
- Instituto de Química del Noroeste Argentino (INQUINOA), Universidad Nacional de Tucumán, CONICET, San Miguel de Tucumán, Argentina.
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16
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Neuhaus F, Mueller D, Tanasescu R, Stefaniu C, Zaffalon PL, Balog S, Ishikawa T, Reiter R, Brezesinski G, Zumbuehl A. Against the rules: pressure induced transition from high to reduced order. SOFT MATTER 2018; 14:3978-3986. [PMID: 29736539 DOI: 10.1039/c8sm00212f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Envisioning the next generation of drug delivery nanocontainers requires more in-depth information on the fundamental physical forces at play in bilayer membranes. In order to achieve this, we combine chemical synthesis with physical-chemical analytical methods and probe the relationship between a molecular structure and its biophysical properties. With the aim of increasing the number of hydrogen bond donors compared to natural phospholipids, a phospholipid compound bearing urea moieties has been synthesized. The new molecules form interdigitated bilayers in aqueous dispersions and self-assemble at soft interfaces in thin layers with distinctive structural order. At lower temperatures, endothermic and exothermic transitions are observed during compression. The LC1 phase is dominated by an intermolecular hydrogen bond network of the urea moieties leading to a very high chain tilt of 52°. During compression and at higher temperatures, presumably this hydrogen bond network is broken allowing a much lower chain tilt of 35°. The extremely different monolayer thicknesses violate the two-dimensional Clausius-Clapeyron equation.
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Affiliation(s)
- Frederik Neuhaus
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland.
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17
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Kornmueller K, Lehofer B, Leitinger G, Amenitsch H, Prassl R. Peptide self-assembly into lamellar phases and the formation of lipid-peptide nanostructures. NANO RESEARCH 2018; 11:913-928. [PMID: 29372005 PMCID: PMC5777605 DOI: 10.1007/s12274-017-1702-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Lipids exhibit an extraordinary polymorphism in self-assembled mesophases, with lamellar phases as biologically most relevant representative. To mimic lipid lamellar phases with amphiphilic designer peptides, seven systematically varied short peptides were engineered. Indeed, four peptide candidates (V4D, V4WD, V4WD2, I4WD2) readily self-assembled into lamellae in aqueous solution: small-angle X-ray scattering patterns (SAXS) revealed ordered lamellar structures with a repeat distance of ~4-5 nm. Transmission electron microscopy (TEM) images confirmed the presence of stacked sheets. Two derivatives (V3D and V4D2) remained as loose aggregates dispersed in solution; one peptide (L4WD2) formed twisted tapes with internal lamellae and an antiparallel β-type monomer alignment. To understand the interaction of peptides with lipids they were mixed with phosphatidylcholines. Low peptide concentrations (1.1 mM) induced the formation of a heterogeneous mixture of vesicular structures: large multilamellar vesicles (d-spacing ~6.3 nm) coexisted with oligo- or unilamellar vesicles (~50 nm in diameter) and bicelle-like structures (~45 nm length, ~18 nm width). High peptide concentrations (11 mM) led to unilamellar vesicles (ULV, diameter ~260-280 nm) with a homogeneous mixing of lipids and peptides. SAXS revealed the temperature-dependent fine structure of these ULVs: at 25 °C the bilayer is in a fully interdigitated state (headgroup-to-headgroup distance dhh ~2.9 nm), whereas at 50 °C this interdigitation opens up (dhh ~3.6 nm). Our results highlight the versatility of self-assembled peptide superstructures: subtle changes in the amino acid composition are key design elements in creating peptide- or lipid-peptide nanostructures with the same richness in morphology as known from the lipid-world.
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Affiliation(s)
- Karin Kornmueller
- Institute of Biophysics, Medical University of Graz,
BioTechMed-Graz, Graz 8010, Austria
| | - Bernhard Lehofer
- Institute of Biophysics, Medical University of Graz,
BioTechMed-Graz, Graz 8010, Austria
| | - Gerd Leitinger
- Institute of Cell Biology, Histology and Embryology, Research Unit
Electron Microscopic Techniques, Medical University of Graz, Graz 8010,
Austria
| | - Heinz Amenitsch
- Institute of Inorganic Chemistry, Graz University of Technology,
Graz 8010, Austria
| | - Ruth Prassl
- Institute of Biophysics, Medical University of Graz,
BioTechMed-Graz, Graz 8010, Austria
- Address correspondence to Ruth Prassl,
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18
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Rozenfeld JHK, Duarte EL, Oliveira TR, Lamy MT. Structural insights on biologically relevant cationic membranes by ESR spectroscopy. Biophys Rev 2017; 9:633-647. [PMID: 28836112 PMCID: PMC5662045 DOI: 10.1007/s12551-017-0304-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 07/28/2017] [Indexed: 12/26/2022] Open
Abstract
Cationic bilayers have been used as models to study membrane fusion, templates for polymerization and deposition of materials, carriers of nucleic acids and hydrophobic drugs, microbicidal agents and vaccine adjuvants. The versatility of these membranes depends on their structure. Electron spin resonance (ESR) spectroscopy is a powerful technique that employs hydrophobic spin labels to probe membrane structure and packing. The focus of this review is the extensive structural characterization of cationic membranes prepared with dioctadecyldimethylammonium bromide or diC14-amidine to illustrate how ESR spectroscopy can provide important structural information on bilayer thermotropic behavior, gel and fluid phases, phase coexistence, presence of bilayer interdigitation, membrane fusion and interactions with other biologically relevant molecules.
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Affiliation(s)
- Julio H K Rozenfeld
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, São Paulo, SP, 04023-062, Brazil
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, R. do Matão 1371, São Paulo, SP, 05508-090, Brazil
| | - Tiago R Oliveira
- Centro de Engenharia, Modelagem e Ciências Sociais Aplicadas, Universidade Federal do ABC, R. Arcturus (Jd Antares), São Bernardo do Campo, SP, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, R. do Matão 1371, São Paulo, SP, 05508-090, Brazil.
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19
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Neuhaus F, Mueller D, Tanasescu R, Balog S, Ishikawa T, Brezesinski G, Zumbuehl A. Vesicle Origami: Cuboid Phospholipid Vesicles Formed by Template-Free Self-Assembly. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201701634] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Frederik Neuhaus
- Department of Chemistry; University of Fribourg; Chemin du Musée 9 1700 Fribourg Switzerland
- National Centres of Competence in Research in Chemical Biology (Geneva) and Bio-inspired Materials; Fribourg Switzerland
| | - Dennis Mueller
- Department of Chemistry; University of Fribourg; Chemin du Musée 9 1700 Fribourg Switzerland
| | - Radu Tanasescu
- Department of Chemistry; University of Fribourg; Chemin du Musée 9 1700 Fribourg Switzerland
| | - Sandor Balog
- Adolphe Merkle Institute; University of Fribourg; Chemin du Verdiers 4 1700 Fribourg Switzerland
| | - Takashi Ishikawa
- Paul Scherrer Institute (PSI); OFLB/010 5232 Villigen PSI Switzerland
| | - Gerald Brezesinski
- Max Planck Institute of Colloids and Interfaces; Research Campus Potsdam-Golm 14476 Potsdam Germany
| | - Andreas Zumbuehl
- Department of Chemistry; University of Fribourg; Chemin du Musée 9 1700 Fribourg Switzerland
- National Centres of Competence in Research in Chemical Biology (Geneva) and Bio-inspired Materials; Fribourg Switzerland
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20
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Neuhaus F, Mueller D, Tanasescu R, Balog S, Ishikawa T, Brezesinski G, Zumbuehl A. Vesicle Origami: Cuboid Phospholipid Vesicles Formed by Template-Free Self-Assembly. Angew Chem Int Ed Engl 2017; 56:6515-6518. [PMID: 28444913 DOI: 10.1002/anie.201701634] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 03/23/2017] [Indexed: 11/08/2022]
Abstract
Phospholipid liposomes are archetypical self-assembled structures. To minimize the surface tension, the vesicles typically are spherical. Deciphering the bilayer code, the basic physical interactions between phospholipids would allow these molecules to be utilized as building blocks for novel, non-spherical structures. A 1,2-diamidophospholipid is presented that self-assembles into a cuboid structure. Owing to intermolecular hydrogen bonding, the bilayer membranes form an exceptionally tight subgel packing, leading to a maximization of flat structural elements and a minimization of any edges. These conditions are optimized in the geometrical structure of a cube. Surprisingly, the lateral surface pressure in the membrane is only one third of the value typically assumed for a bilayer membrane, questioning a long-standing rule-of-thumb.
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Affiliation(s)
- Frederik Neuhaus
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700, Fribourg, Switzerland.,National Centres of Competence in Research in Chemical Biology (Geneva) and Bio-inspired Materials, Fribourg, Switzerland
| | - Dennis Mueller
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700, Fribourg, Switzerland
| | - Radu Tanasescu
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700, Fribourg, Switzerland
| | - Sandor Balog
- Adolphe Merkle Institute, University of Fribourg, Chemin du Verdiers 4, 1700, Fribourg, Switzerland
| | - Takashi Ishikawa
- Paul Scherrer Institute (PSI), OFLB/010, 5232, Villigen PSI, Switzerland
| | - Gerald Brezesinski
- Max Planck Institute of Colloids and Interfaces, Research Campus Potsdam-Golm, 14476, Potsdam, Germany
| | - Andreas Zumbuehl
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700, Fribourg, Switzerland.,National Centres of Competence in Research in Chemical Biology (Geneva) and Bio-inspired Materials, Fribourg, Switzerland
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21
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Hubbard ATM, Barker R, Rehal R, Vandera KKA, Harvey RD, Coates ARM. Mechanism of Action of a Membrane-Active Quinoline-Based Antimicrobial on Natural and Model Bacterial Membranes. Biochemistry 2017; 56:1163-1174. [PMID: 28156093 DOI: 10.1021/acs.biochem.6b01135] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
HT61 is a quinoline-derived antimicrobial, which exhibits bactericidal potency against both multiplying and quiescent methicillin resistant and sensitive Staphylococcus aureus, and has been proposed as an adjunct for other antimicrobials to extend their usefulness in the face of increasing antimicrobial resistance. In this study, we have examined HT61's effect on the permeability of S. aureus membranes and whether this putative activity can be attributed to an interaction with lipid bilayers. Using membrane potential and ATP release assays, we have shown that HT61 disrupts the membrane enough to result in depolarization of the membrane and release of intercellular constituents at concentrations above and below the minimum inhibitory concentration of the drug. Utilizing both monolayer subphase injection and neutron reflectometry, we have shown that increasing the anionic lipid content of the membrane leads to a more marked effect of the drug. In bilayers containing 25 mol % phosphatidylglycerol, neutron reflectometry data suggest that exposure to HT61 increases the level of solvent in the hydrophobic region of the membrane, which is indicative of gross structural damage. Increasing the proportion of PG elicits a concomitant level of membrane damage, resulting in almost total destruction when 75 mol % phosphatidylglycerol is present. We therefore propose that HT61's primary action is directed toward the cytoplasmic membrane of Gram-positive bacteria.
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Affiliation(s)
- Alasdair T M Hubbard
- Medical Microbiology, Institute for Infection and Immunity, St George's, University of London , Cranmer Terrace, London SW17 ORE, U.K
| | - Robert Barker
- Institut Laue Langevin , 71 avenue des Martyrs, 38042 Grenoble, France
| | - Reg Rehal
- Institute of Pharmaceutical Science, King's College London , Franklin Wilkins Building, 150 Stamford Street, London SE1 9NH, U.K
| | - Kalliopi-Kelli A Vandera
- Institute of Pharmaceutical Science, King's College London , Franklin Wilkins Building, 150 Stamford Street, London SE1 9NH, U.K
| | - Richard D Harvey
- Institute of Pharmaceutical Science, King's College London , Franklin Wilkins Building, 150 Stamford Street, London SE1 9NH, U.K
| | - Anthony R M Coates
- Medical Microbiology, Institute for Infection and Immunity, St George's, University of London , Cranmer Terrace, London SW17 ORE, U.K
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22
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Klausen LH, Fuhs T, Dong M. Mapping surface charge density of lipid bilayers by quantitative surface conductivity microscopy. Nat Commun 2016; 7:12447. [PMID: 27561322 PMCID: PMC5007656 DOI: 10.1038/ncomms12447] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 07/04/2016] [Indexed: 01/21/2023] Open
Abstract
Local surface charge density of lipid membranes influences membrane–protein interactions leading to distinct functions in all living cells, and it is a vital parameter in understanding membrane-binding mechanisms, liposome design and drug delivery. Despite the significance, no method has so far been capable of mapping surface charge densities under physiologically relevant conditions. Here, we use a scanning nanopipette setup (scanning ion-conductance microscope) combined with a novel algorithm to investigate the surface conductivity near supported lipid bilayers, and we present a new approach, quantitative surface conductivity microscopy (QSCM), capable of mapping surface charge density with high-quantitative precision and nanoscale resolution. The method is validated through an extensive theoretical analysis of the ionic current at the nanopipette tip, and we demonstrate the capacity of QSCM by mapping the surface charge density of model cationic, anionic and zwitterionic lipids with results accurately matching theoretical values. Surface charges on lipid bilayers deeply influence the way proteins interact with cellular membranes, yet their precise quantification has proven challenging. Here, the authors report on a quantitative method to map and evaluate surface charge densities under physiological conditions.
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Affiliation(s)
- Lasse Hyldgaard Klausen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.,Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen Ø DK-2100, Denmark
| | - Thomas Fuhs
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Mingdong Dong
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
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23
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Niroomand H, Venkatesan GA, Sarles SA, Mukherjee D, Khomami B. Lipid-Detergent Phase Transitions During Detergent-Mediated Liposome Solubilization. J Membr Biol 2016; 249:523-38. [DOI: 10.1007/s00232-016-9894-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 03/24/2016] [Indexed: 11/24/2022]
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24
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Marquardt D, Geier B, Pabst G. Asymmetric lipid membranes: towards more realistic model systems. MEMBRANES 2015; 5:180-96. [PMID: 25955841 PMCID: PMC4496639 DOI: 10.3390/membranes5020180] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 04/28/2015] [Indexed: 01/23/2023]
Abstract
Despite the ubiquity of transbilayer asymmetry in natural cell membranes, the vast majority of existing research has utilized chemically well-defined symmetric liposomes, where the inner and outer bilayer leaflets have the same composition. Here, we review various aspects of asymmetry in nature and in model systems in anticipation for the next phase of model membrane studies.
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Affiliation(s)
- Drew Marquardt
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstr 50/III, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, 8010, Austria.
| | - Barbara Geier
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstr 50/III, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, 8010, Austria.
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstr 50/III, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, 8010, Austria.
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25
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Abstract
Bilayers formed by phospholipids are fundamental structures of biological membranes. The mechanical perturbation brought about by pressure significantly affects the membrane states of phospholipid bilayers. In this chapter, we focus our attention on the pressure responsivity for bilayers of some major phospholipids contained in biological membranes. At first, the membrane states and phase transitions of phospholipid bilayers depending on water content, temperature and pressure are explained by using the bilayer phase diagrams of dipalmitoylphosphatidylcholine (DPPC), which is the most familiar phospholipid in model membrane studies. Subsequently, the thermotropic and barotropic bilayer phase behavior of various kinds of phospholipids with different molecular structures is discussed from the comparison of their temperature--pressure phase diagrams to that of the DPPC bilayer. It turns out that a slight change in the molecular structure of the phospholipids produces a significant difference in the bilayer phase behavior. The systematic pressure studies on the phase behavior of the phospholipid bilayers reveal not only the pressure responsivity for the bilayers but also the role and meaning of several important phospholipids existing in real biological membranes.
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26
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Le Brun AP, Haigh CL, Drew SC, James M, Boland MP, Collins SJ. Neutron reflectometry studies define prion protein N-terminal peptide membrane binding. Biophys J 2014; 107:2313-24. [PMID: 25418300 PMCID: PMC4241452 DOI: 10.1016/j.bpj.2014.09.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/08/2014] [Accepted: 09/19/2014] [Indexed: 10/24/2022] Open
Abstract
The prion protein (PrP), widely recognized to misfold into the causative agent of the transmissible spongiform encephalopathies, has previously been shown to bind to lipid membranes with binding influenced by both membrane composition and pH. Aside from the misfolding events associated with prion pathogenesis, PrP can undergo various posttranslational modifications, including internal cleavage events. Alpha- and beta-cleavage of PrP produces two N-terminal fragments, N1 and N2, respectively, which interact specifically with negatively charged phospholipids at low pH. Our previous work probing N1 and N2 interactions with supported bilayers raised the possibility that the peptides could insert deeply with minimal disruption. In the current study we aimed to refine the binding parameters of these peptides with lipid bilayers. To this end, we used neutron reflectometry to define the structural details of this interaction in combination with quartz crystal microbalance interrogation. Neutron reflectometry confirmed that peptides equivalent to N1 and N2 insert into the interstitial space between the phospholipid headgroups but do not penetrate into the acyl tail region. In accord with our previous studies, interaction was stronger for the N1 fragment than for the N2, with more peptide bound per lipid. Neutron reflectometry analysis also detected lengthening of the lipid acyl tails, with a concurrent decrease in lipid area. This was most evident for the N1 peptide and suggests an induction of increased lipid order in the absence of phase transition. These observations stand in clear contrast to the findings of analogous studies of Ab and ?-synuclein and thereby support the possibility of a functional role for such N-terminal fragment-membrane interactions.
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Affiliation(s)
- Anton P Le Brun
- Bragg Institute, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, New South Wales, 2234, Australia
| | - Cathryn L Haigh
- Department of Pathology, Kenneth Myer Building, The University of Melbourne, Victoria, 3010, Australia
| | - Simon C Drew
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, 3010, Australia
| | - Michael James
- Bragg Institute, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, New South Wales, 2234, Australia; School of Chemistry, University of New South Wales, Kensington, New South Wales, 2052, Australia
| | - Martin P Boland
- Department of Pathology, Kenneth Myer Building, The University of Melbourne, Victoria, 3010, Australia
| | - Steven J Collins
- Department of Pathology, Kenneth Myer Building, The University of Melbourne, Victoria, 3010, Australia.
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27
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Su C, Xia Y, Sun J, Wang N, Zhu L, Chen T, Huang Y, Liang D. Liposomes physically coated with peptides: preparation and characterization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:6219-6227. [PMID: 24826785 DOI: 10.1021/la501296r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Physically coating liposomes with peptides of desirable functions is an economic, versatile, and less time-consuming approach to prepare drug delivery vehicles. In this work, we designed three peptides-Ac-WWKKKGGNNN-NH2 (W2K3), Ac-WWRRRGGNNN-NH2(W2R3), Ac-WWGGGGGNNN-NH2(W2G3)-and studied their coating ability on negatively charged liposomes. It was found that the coating was mainly driven by the electrostatic interaction between the peptides' cationic side groups and the acidic lipids, which also mediated the "anchoring " of Trp residuals in the interfacial region of lipid bilayers. At the same conditions, the amount of the coated W2R3 was more than that of W2K3, but the stability of the liposome coated with W2R3 was deteriorated. This was caused by the delocalized charge of the guanidinium group of arginine. The coating of the peptide rendered the liposome pH-responsive behavior but did not prominently change the phase transition temperature. The liposome coated with peptides displayed appropriate pH/temperature dual responsive characteristics and was able to release the content in a controlled manner.
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Affiliation(s)
- Cuicui Su
- Beijing National Laboratory for Molecular Sciences and the Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
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28
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How CW, Teruel JA, Ortiz A, Montenegro MF, Rodríguez-López JN, Aranda FJ. Effects of a synthetic antitumoral catechin and its tyrosinase-processed product on the structural properties of phosphatidylcholine membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1215-24. [DOI: 10.1016/j.bbamem.2014.01.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/07/2014] [Accepted: 01/27/2014] [Indexed: 10/25/2022]
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29
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Teruel JA, Ortiz A, Aranda FJ. Interactions of a bacterial trehalose lipid with phosphatidylglycerol membranes at low ionic strength. Chem Phys Lipids 2014; 181:34-9. [PMID: 24704470 DOI: 10.1016/j.chemphyslip.2014.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/21/2014] [Accepted: 03/26/2014] [Indexed: 11/16/2022]
Abstract
Trehalose lipids are bacterial biosurfactants which present interesting physicochemical and biological properties. These glycolipids have a number of different commercial applications and there is an increasing interest in their use as therapeutic agents. The amphiphilic nature of trehalose lipids points to the membrane as their hypothetical site of action and therefore the study of the interaction between these biosurfactants and biological membranes is critical. In this study, we examine the interactions between a trehalose lipid (TL) from Rhodococcus sp. and dimyristoylphosphatidylglycerol (DMPG) membranes at low ionic strength, by means of differential scanning calorimetry, light scattering, fluorescence polarization and infrared spectroscopy. We describe that there are extensive interactions between TL and DMPG involving the perturbation of the thermotropic intermediate phase of the phospholipid, the destabilization and shifting of the DMPG gel to liquid crystalline phase transition to lower temperatures, the perturbation of the sample transparency, and the modification of the order of the phospholipid palisade in the gel phase. We also report an increase of fluidity of the phosphatidylglycerol acyl chains and dehydration of the interfacial region of the bilayer. These changes would increase the monolayer negative spontaneous curvature of the phospholipid explaining the destabilizing effect on the intermediate state exerted by this biosurfactant. The observations contribute to get insight into the biological mechanism of action of the biosurfactant and help to understand the properties of the intermediate phase display by DMPG at low ionic strength.
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Affiliation(s)
- José A Teruel
- Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain
| | - Antonio Ortiz
- Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain
| | - Francisco J Aranda
- Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain.
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30
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Rozenfeld JHK, Duarte EL, Oliveira TR, Lonez C, Ruysschaert JM, Lamy MT. Oligonucleotide adsorption affects phase transition but not interdigitation of diC14-amidine bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:11102-11108. [PMID: 23926901 DOI: 10.1021/la4016004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this work, we investigate the effect of a small single-stranded oligonucleotide (ODN) on the colloid stability and structure of cationic diC14-amidine liposomes. Dynamic light scattering (DLS) shows that small, stable, anionic assemblies are formed in presence of excess ODN negative charge. This charge overcompensation condition was further characterized. A less cooperative bilayer phase transition is observed by differential scanning calorimetry (DSC). Electron spin resonance (ESR) spectra of probes at different bilayer depths show that ODN electrostatic adsorption increases the rigidity of both interdigitated gel and lamellar fluid phases. The increase in gel phase rigidity could be explained by the transformation of an adjacent to an interpenetrated interdigitation. Interdigitated fusogenic bilayers may find interesting applications in delivery of therapeutic oligonucleotides.
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31
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Kurniawan Y, Venkataramanan KP, Piernavieja M, Scholz C, Bothun GD. Role of Ionic Strength on n-Butanol Partitioning into Anionic Dipalmitoyl Phosphatidylcholine/Phosphatidylglycerol Vesicles. J Phys Chem B 2013; 117:8484-9. [DOI: 10.1021/jp403735h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yogi Kurniawan
- Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Road, Kingston,
Rhode Island, United States
| | - Keerthi P. Venkataramanan
- Biotechnology Science and Engineering
Program, University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, Alabama, United States
| | - Mar Piernavieja
- Department of Chemical and Materials
Engineering, University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, Alabama, United States
| | - Carmen Scholz
- Department of Chemistry, University of Alabama in Huntsville, 301 Sparkman Drive,
Huntsville, Alabama, United States
| | - Geoffrey D. Bothun
- Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Road, Kingston,
Rhode Island, United States
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32
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Varela AR, Gonçalves da Silva AM, Fedorov A, Futerman AH, Prieto M, Silva LC. Effect of glucosylceramide on the biophysical properties of fluid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013. [DOI: 10.1016/j.bbamem.2012.11.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Pan J, Heberle FA, Tristram-Nagle S, Szymanski M, Koepfinger M, Katsaras J, Kučerka N. Molecular structures of fluid phase phosphatidylglycerol bilayers as determined by small angle neutron and X-ray scattering. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2135-48. [PMID: 22583835 DOI: 10.1016/j.bbamem.2012.05.007] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 03/22/2012] [Accepted: 05/07/2012] [Indexed: 10/28/2022]
Abstract
We have determined the molecular structures of commonly used phosphatidylglycerols (PGs) in the commonly accepted biologically relevant fluid phase. This was done by simultaneously analyzing small angle neutron and X-ray scattering data, with the constraint of measured lipid volumes. We report the temperature dependence of bilayer parameters obtained using the one-dimensional scattering density profile model - which was derived from molecular dynamics simulations - including the area per lipid, the overall bilayer thickness, as well as other intrabilayer parameters (e.g., hydrocarbon thickness). Lipid areas are found to be larger than their phosphatidylcholine (PC) counterparts, a result likely due to repulsive electrostatic interactions taking place between the charged PG headgroups even in the presence of sodium counterions. In general, PG and PC bilayers show a similar response to changes in temperature and chain length, but differ in their response to chain unsaturation. For example, compared to PC bilayers, the inclusion of a first double bond in PG lipids results in a smaller incremental change to the area per lipid and bilayer thickness. However, the extrapolated lipid area of saturated PG lipids to infinite chain length is found to be similar to that of PCs, an indication of the glycerol-carbonyl backbone's pivotal role in influencing the lipid-water interface.
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Affiliation(s)
- Jianjun Pan
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100, USA.
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34
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Cardoso AM, Trabulo S, Cardoso AL, Lorents A, Morais CM, Gomes P, Nunes C, Lúcio M, Reis S, Padari K, Pooga M, Pedroso de Lima MC, Jurado AS. S4(13)-PV cell-penetrating peptide induces physical and morphological changes in membrane-mimetic lipid systems and cell membranes: Implications for cell internalization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:877-88. [DOI: 10.1016/j.bbamem.2011.12.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 12/05/2011] [Accepted: 12/21/2011] [Indexed: 01/09/2023]
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35
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Lateral order in gel, subgel and crystalline phases of lipid membranes: Wide-angle X-ray scattering. Chem Phys Lipids 2012; 165:59-76. [DOI: 10.1016/j.chemphyslip.2011.11.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 10/31/2011] [Accepted: 11/03/2011] [Indexed: 11/21/2022]
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36
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Correlation between the ripple phase and stripe domains in membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2849-58. [DOI: 10.1016/j.bbamem.2011.08.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 08/12/2011] [Accepted: 08/16/2011] [Indexed: 12/19/2022]
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37
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Cirac AD, Moiset G, Mika JT, Koçer A, Salvador P, Poolman B, Marrink SJ, Sengupta D. The molecular basis for antimicrobial activity of pore-forming cyclic peptides. Biophys J 2011; 100:2422-31. [PMID: 21575576 DOI: 10.1016/j.bpj.2011.03.057] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/18/2011] [Accepted: 03/31/2011] [Indexed: 11/29/2022] Open
Abstract
The mechanism of action of antimicrobial peptides is, to our knowledge, still poorly understood. To probe the biophysical characteristics that confer activity, we present here a molecular-dynamics and biophysical study of a cyclic antimicrobial peptide and its inactive linear analog. In the simulations, the cyclic peptide caused large perturbations in the bilayer and cooperatively opened a disordered toroidal pore, 1-2 nm in diameter. Electrophysiology measurements confirm discrete poration events of comparable size. We also show that lysine residues aligning parallel to each other in the cyclic but not linear peptide are crucial for function. By employing dual-color fluorescence burst analysis, we show that both peptides are able to fuse/aggregate liposomes but only the cyclic peptide is able to porate them. The results provide detailed insight on the molecular basis of activity of cyclic antimicrobial peptides.
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Affiliation(s)
- Anna D Cirac
- Department of Biochemistry and Biophysical Chemistry, Groningen Biomolecular Sciences, Netherlands
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38
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Loew C, Riske KA, Lamy MT, Seelig J. Thermal phase behavior of DMPG bilayers in aqueous dispersions as revealed by 2H- and 31P-NMR. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:10041-10049. [PMID: 21732628 DOI: 10.1021/la201027p] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The synthetic lipid 1,2-dimyristoyl-sn-3-phosphoglycerol (DMPG), when dispersed in water/NaCl exhibits a complex phase behavior caused by its almost unlimited swelling in excess water. Using deuterium ((2)H)- and phosphorus ((31)P)-NMR we have studied the molecular properties of DMPG/water/NaCl dispersions as a function of lipid and NaCl concentration. We have measured the order profile of the hydrophobic part of the lipid bilayer with deuterated DMPG while the orientation of the phosphoglycerol headgroup was deduced from the (31)P NMR chemical shielding anisotropy. At temperatures >30 °C we observe well-resolved (2)H- and (31)P NMR spectra not much different from other liquid crystalline bilayers. From the order profiles it is possible to deduce the average length of the flexible fatty acyl chain. Unusual spectra are obtained in the temperature interval of 20-25 °C, indicating one or several phase transitions. The most dramatic changes are seen at low lipid concentration and low ionic strength. Under these conditions and at 25 °C, the phosphoglycerol headgroup rotates into the hydrocarbon layer and the hydrocarbon chains show larger flexing motions than at higher temperatures. The orientation of the phosphoglycerol headgroup depends on the bilayer surface charge and correlates with the degree of dissociation of DMPG-Na(+). The larger the negative surface charge, the more the headgroup rotates toward the nonpolar region.
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Affiliation(s)
- Caroline Loew
- Biozentrum, Division of Biophysical Chemistry, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
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39
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Ortiz A, Teruel JA, Manresa Á, Espuny MJ, Marqués A, Aranda FJ. Effects of a bacterial trehalose lipid on phosphatidylglycerol membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2067-72. [PMID: 21600191 DOI: 10.1016/j.bbamem.2011.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 05/02/2011] [Indexed: 10/18/2022]
Abstract
Bacterial trehalose lipids are biosurfactants with potential application in the biomedical/healthcare industry due to their interesting biological properties. Given the amphiphilic nature of trehalose lipids, the understanding of the molecular mechanism of their biological action requires that the interaction between biosurfactant and membranes is known. In this study we examine the interactions between a trehalose lipid from Rhodococcus sp. and dimyristoylphosphatidylglycerol membranes by means of differential scanning calorimetry, X-ray diffraction, infrared spectroscopy and fluorescence polarization. We report that there are extensive interactions between trehalose lipid and dimyristoylphosphatidylglycerol involving the perturbation of the thermotropic gel to liquid-crystalline phase transition of the phospholipid, the increase of fluidity of the phosphatidylglycerol acyl chains and dehydration of the interfacial region of the bilayer, and the modulation of the order of the phospholipid bilayer. The observations are interpreted in terms of structural perturbations affecting the function of the membrane that might underline the biological actions of the trehalose lipid.
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Affiliation(s)
- Antonio Ortiz
- Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain
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40
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Structural basis for the enhanced activity of cyclic antimicrobial peptides: the case of BPC194. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2197-205. [PMID: 21586269 DOI: 10.1016/j.bbamem.2011.05.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 04/29/2011] [Accepted: 05/02/2011] [Indexed: 01/17/2023]
Abstract
We report the molecular basis for the differences in activity of cyclic and linear antimicrobial peptides. We iteratively performed atomistic molecular dynamics simulations and biophysical measurements to probe the interaction of a cyclic antimicrobial peptide and its inactive linear analogue with model membranes. We establish that, relative to the linear peptide, the cyclic one binds stronger to negatively charged membranes. We show that only the cyclic peptide folds at the membrane interface and adopts a β-sheet structure characterised by two turns. Subsequently, the cyclic peptide penetrates deeper into the bilayer while the linear peptide remains essentially at the surface. Finally, based on our comparative study, we propose a model characterising the mode of action of cyclic antimicrobial peptides. The results provide a chemical rationale for enhanced activity in certain cyclic antimicrobial peptides and can be used as a guideline for design of novel antimicrobial peptides.
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41
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Kleberg K, Jacobsen J, Müllertz A. Characterising the behaviour of poorly water soluble drugs in the intestine: application of biorelevant media for solubility, dissolution and transport studies. J Pharm Pharmacol 2011; 62:1656-68. [PMID: 21039549 DOI: 10.1111/j.2042-7158.2010.01023.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Based on the knowledge of human intestinal fluids, compositions of biorelevant media and their impact on solubility, dissolution and permeability studies of poorly soluble drug compounds are discussed. KEY FINDINGS Human intestinal fluids show large variations with regard to composition and pH, which complicate the selection of biorelevant media. The influence of concentration and ratio of bile salts, phospholipids and hydrolysis products, such as monoglycerides and free fatty acids, in well characterised media, on the solubility, dissolution and permeability of a given drug provides valuable information on the behaviour of the drug in the intestine, thus enabling the prediction of the in-vivo absorption. SUMMARY This review discusses the implications of biorelevant media composition on the solubility, dissolution and permeability of poorly soluble drug compounds. Biorelevant media contain bile salts and phospholipids and when simulating the fed state also monoglycerides and free fatty acids. Solubility of some poorly soluble drugs increase independently of the type of surfactants included in the biorelevant media, while others have a higher solubility in monoglyceride- and fatty acid-containing media. This is independent of the log P (the octanol-water partition coefficient) of the drug. The use of biorelevant dissolution media improves the correlation to in-vivo data, compared with compendial media, and although the field of permeability studies is complex the use of biorelevant media in this setting shows promise with respect to a better prediction of absorption.
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Affiliation(s)
- Karen Kleberg
- Department of Pharmaceutics and Analytical Chemistry Bioneer:FARMA, Faculty of Pharmaceutical Sciences, University of Copenhagen, Denmark
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42
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Implication of sphingomyelin/ceramide molar ratio on the biological activity of sphingomyelinase. Biophys J 2010; 99:499-506. [PMID: 20643068 DOI: 10.1016/j.bpj.2010.04.028] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/12/2010] [Accepted: 04/15/2010] [Indexed: 12/11/2022] Open
Abstract
Sphingolipid signaling plays an important, yet not fully understood, role in diverse aspects of cellular life. Sphingomyelinase is a major enzyme in these signaling pathways, catalyzing hydrolysis of sphingomyelin to ceramide and phosphocholine. To address the related membrane dynamical structural changes and their feedback to enzyme activity, we have studied the effect of enzymatically generated ceramide in situ on the properties of a well-defined lipid model system. We found a gel-phase formation that was about four times faster than ceramide generation due to ceramide-sphingomyelin pairing. The gel-phase formation slowed down when the ceramide molar ratios exceeded those of sphingomyelin and stopped just at the solubility limit of ceramide, due to unfavorable pairwise interactions of ceramide with itself and with monounsaturated phosphatidylcholine. A remarkable correlation to in vitro experiments suggests a regulation of sphingomyelinase activity based on the sphingomyelin/ceramide molar ratio.
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43
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Stȩpniewski M, Bunker A, Pasenkiewicz-Gierula M, Karttunen M, Róg T. Effects of the Lipid Bilayer Phase State on the Water Membrane Interface. J Phys Chem B 2010; 114:11784-92. [DOI: 10.1021/jp104739a] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michał Stȩpniewski
- Department of Computational Biophysics and Bioinformatics, Faculty of Biotechnology, Biochemistry and Biophysics, Jagiellonian University, Gronostajowa 7, Poland, Centre for Drug Research, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014, University of Helsinki, Finland, Departments of Chemistry and Applied Physics, Aalto University, P.O. Box-16100, FI-00076 AALTO, Finland, Department of Applied Mathematics, The University of Western Ontario, 1151 Richmond Street North, London, Ontario,
| | - Alex Bunker
- Department of Computational Biophysics and Bioinformatics, Faculty of Biotechnology, Biochemistry and Biophysics, Jagiellonian University, Gronostajowa 7, Poland, Centre for Drug Research, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014, University of Helsinki, Finland, Departments of Chemistry and Applied Physics, Aalto University, P.O. Box-16100, FI-00076 AALTO, Finland, Department of Applied Mathematics, The University of Western Ontario, 1151 Richmond Street North, London, Ontario,
| | - Marta Pasenkiewicz-Gierula
- Department of Computational Biophysics and Bioinformatics, Faculty of Biotechnology, Biochemistry and Biophysics, Jagiellonian University, Gronostajowa 7, Poland, Centre for Drug Research, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014, University of Helsinki, Finland, Departments of Chemistry and Applied Physics, Aalto University, P.O. Box-16100, FI-00076 AALTO, Finland, Department of Applied Mathematics, The University of Western Ontario, 1151 Richmond Street North, London, Ontario,
| | - Mikko Karttunen
- Department of Computational Biophysics and Bioinformatics, Faculty of Biotechnology, Biochemistry and Biophysics, Jagiellonian University, Gronostajowa 7, Poland, Centre for Drug Research, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014, University of Helsinki, Finland, Departments of Chemistry and Applied Physics, Aalto University, P.O. Box-16100, FI-00076 AALTO, Finland, Department of Applied Mathematics, The University of Western Ontario, 1151 Richmond Street North, London, Ontario,
| | - Tomasz Róg
- Department of Computational Biophysics and Bioinformatics, Faculty of Biotechnology, Biochemistry and Biophysics, Jagiellonian University, Gronostajowa 7, Poland, Centre for Drug Research, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014, University of Helsinki, Finland, Departments of Chemistry and Applied Physics, Aalto University, P.O. Box-16100, FI-00076 AALTO, Finland, Department of Applied Mathematics, The University of Western Ontario, 1151 Richmond Street North, London, Ontario,
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44
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Prossnigg F, Hickel A, Pabst G, Lohner K. Packing behaviour of two predominant anionic phospholipids of bacterial cytoplasmic membranes. Biophys Chem 2010; 150:129-35. [PMID: 20451316 PMCID: PMC2905515 DOI: 10.1016/j.bpc.2010.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 04/07/2010] [Accepted: 04/08/2010] [Indexed: 11/08/2022]
Abstract
Phosphatidylglycerol and cardiolipin represent the most abundant anionic phospholipid components of cytoplasmic bacterial membranes and thus are used as constituents for membrane mimetic systems. In this study, we have characterized the temperature dependent phase behaviour of the binary system dipalmitoyl-phosphatidylglycerol (DPPG) and tetramyristoyl-cardiolipin (TMCL) using microcalorimetry and X-ray scattering techniques. Both lipids exhibited a very similar main transition temperature (∼ 41 °C), showing a minimum (39.4 °C) for the binary mixtures at XDPPG = 0.8, and exhibited low-temperature phase transitions, which were abolished by incorporation of small amounts (≤ 10 mol%) of the other lipid component. Therefore, over a wide temperature and composition range a lamellar Lβ gel phase is the predominant structure below the chain melting transition, characterized by a relatively broad wide-angle peak for XDPPG ≤ 0.8. This observation suggests the existence of packing inconsistencies of the TMCL/DPPG hydrocarbon lattices in the gel phase, supported by the small average size of lipid clusters (∼ 50 lipids) within this composition range. The bilayer thickness for the lamellar-gel phase showed a monotonic increase (56 Å for TMCL to about 58 Å for XDPPG = 0.8 at 30 °C), which may be explained by different degrees of partial interdigitation of the acyl chains to compensate for the differences in the hydrocarbon lengths of DPPG and TMCL in the Lβ phase.
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Affiliation(s)
- Florian Prossnigg
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Schmiedlstrasse 6, A-8042 Graz, Austria
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Pabst G, Kucerka N, Nieh MP, Rheinstädter MC, Katsaras J. Applications of neutron and X-ray scattering to the study of biologically relevant model membranes. Chem Phys Lipids 2010; 163:460-79. [PMID: 20361949 DOI: 10.1016/j.chemphyslip.2010.03.010] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 03/23/2010] [Accepted: 03/24/2010] [Indexed: 11/19/2022]
Abstract
Scattering techniques, in particular electron, neutron and X-ray scattering have played a major role in elucidating the static and dynamic structure of biologically relevant membranes. Importantly, neutron and X-ray scattering have evolved to address new sample preparations that better mimic biological membranes. In this review, we will report on some of the latest model membrane results, and the neutron and X-ray techniques that were used to obtain them.
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Affiliation(s)
- G Pabst
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, A-8042 Graz, Austria
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Pimthon J, Willumeit R, Lendlein A, Hofmann D. Membrane association and selectivity of the antimicrobial peptide NK-2: a molecular dynamics simulation study. J Pept Sci 2009; 15:654-67. [DOI: 10.1002/psc.1165] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Lohner K, Prossnigg F. Biological activity and structural aspects of PGLa interaction with membrane mimetic systems. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1656-66. [DOI: 10.1016/j.bbamem.2009.05.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 05/21/2009] [Accepted: 05/22/2009] [Indexed: 10/20/2022]
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Pimthon J, Willumeit R, Lendlein A, Hofmann D. All-atom molecular dynamics simulation studies of fully hydrated gel phase DPPG and DPPE bilayers. J Mol Struct 2009. [DOI: 10.1016/j.molstruc.2008.12.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Using x-ray diffraction, solid-state 2H-NMR, differential scanning calorimetry, and dilatometry, we have observed a perturbation of saturated acyl chain phosphatidylglycerol bilayers by the antimicrobial peptide peptidyl-glycylleucine-carboxyamide (PGLa) that is dependent on the length of the hydrocarbon chain. In the gel phase, PGLa induces a quasi-interdigitated phase, previously reported also for other peptides, which is most pronounced for C18 phosphatidylglycerol. In the fluid phase, we found an increase of the membrane thickness and NMR order parameter for C14 and C16 phosphatidylglycerol bilayers, though not for C18. The data is best understood in terms of a close hydrophobic match between the C18 bilayer core and the peptide length when PGLa is inserted with its helical axis normal to the bilayer surface. The C16 acyl chains appear to stretch to accommodate PGLa, whereas tilting within the bilayer seems to be energetically favorable for the peptide when inserted into bilayers of C14 phosphatidylglycerol. In contrast to the commonly accepted membrane thinning effect of antimicrobial peptides, the data demonstrate that pore formation does not necessarily relate to changes in the overall bilayer structure.
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Zbytovská J, Kiselev M, Funari S, Garamus V, Wartewig S, Palát K, Neubert R. Influence of cholesterol on the structure of stratum corneum lipid model membrane. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2008.06.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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