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Pushpa Ragini S, Dyett BP, Sarkar S, Zhai J, White JF, Banerjee R, Drummond CJ, Conn CE. A systematic study of the effect of lipid architecture on cytotoxicity and cellular uptake of cationic cubosomes. J Colloid Interface Sci 2024; 663:82-93. [PMID: 38394820 DOI: 10.1016/j.jcis.2024.02.099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/26/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024]
Abstract
HYPOTHESIS Lipid nanoparticles containing a cationic lipid are increasingly used in drug and gene delivery as they can display improved cellular uptake, enhanced loading for anionic cargo such as siRNA and mRNA or exhibit additional functionality such as cytotoxicity against cancer cells. This research study tests the hypothesis that the molecular structure of the cationic lipid influences the structure of the lipid nanoparticle, the cellular uptake, and the resultant cytotoxicity. EXPERIMENTS Three potentially cytotoxic cationic lipids, with systematic variations to the hydrophobic moiety, were designed and synthesised. All the three cationic lipids synthesised contain pharmacophores such as the bicyclic coumarin group (CCA12), the tricyclic etodolac moiety (ETD12), or the large pentacyclic triterpenoid "ursolic" group (U12) conjugated to a quaternary ammonium cationic lipid containing twin C12 chains. The cationic lipids were doped into monoolein cubosomes at a range of concentrations from 0.1 mol% to 5 mol% and the effect of the lipid molecular architecture on the cubosome phase behaviour was assessed using a combination of Small Angle X-Ray Scattering (SAXS), Dynamic Light Scattering (DLS), zeta-potential and cryo-Transmission Electron Microscopy (Cryo-TEM). The resulting cytotoxicity of these particles against a range of cancerous and non-cancerous cell-lines was assessed, along with their cellular uptake. FINDINGS The molecular architecture of the cationic lipid was linked to the internal nanostructure of the resulting cationic cubosomes with a transition to more curved cubic and hexagonal phases generally observed. Cubosomes formed from the cationic lipid CCA12 were found to have improved cellular uptake and significantly higher cytotoxicity than the cationic lipids ETD12 and U12 against the gastric cancer cell-line (AGS) at lipid concentrations ≥ 75 µg/mL. CCA12 cationic cubosomes also displayed reasonable cytotoxicity against the prostate cancer PC-3 cell-line at lipid concentrations ≥ 100 µg/mL. In contrast, 2.5 mol% ETD12 and 2.5 mol% U12 cubosomes were generally non-toxic against both cancerous and non-cancerous cell lines over the entire concentration range tested. The molecular architecture of the cationic lipid was found to influence the cubosome phase behaviour, the cellular uptake and the toxicity although further studies are necessary to determine the exact relationship between structure and cellular uptake across a range of cell lines.
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Affiliation(s)
- S Pushpa Ragini
- Department of Oils, lipids science and technology, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India; Academy of Scientific and Innovation Research (AcSIR), Ghaziabad, 201002, India; STEM College, RMIT University, Melbourne 3000, Victoria, Australia
| | - Brendan P Dyett
- STEM College, RMIT University, Melbourne 3000, Victoria, Australia
| | - Sampa Sarkar
- STEM College, RMIT University, Melbourne 3000, Victoria, Australia
| | - Jiali Zhai
- STEM College, RMIT University, Melbourne 3000, Victoria, Australia
| | - Jacinta F White
- CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3168, Australia
| | - Rajkumar Banerjee
- Department of Oils, lipids science and technology, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India; Academy of Scientific and Innovation Research (AcSIR), Ghaziabad, 201002, India
| | - Calum J Drummond
- STEM College, RMIT University, Melbourne 3000, Victoria, Australia.
| | - Charlotte E Conn
- STEM College, RMIT University, Melbourne 3000, Victoria, Australia.
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Ahmed M, Islam MZ, Billah MM, Yamazaki M. Effect of Phosphatidylethanolamine on Pore Formation Induced by the Antimicrobial Peptide PGLa. J Phys Chem B 2024; 128:2684-2696. [PMID: 38450565 DOI: 10.1021/acs.jpcb.3c08098] [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: 03/08/2024]
Abstract
Most antimicrobial peptides (AMPs) induce pore formation and a burst of lipid bilayers and plasma membranes. This causes severe leakage of the internal contents and cell death. The AMP PGLa forms nanopores in giant unilamellar vesicles (GUVs) comprising dioleoylphosphatidylcholine (DOPC) and dioleoylphosphatidylglycerol (DOPG). We here elucidated the effect of the line tension of a prepore rim on PGLa-induced nanopore formation by investigating the interaction of PGLa with single GUVs comprising dioleoylphosphatidylethanolamine (DOPE)/DOPG (6:4) in buffer using the single GUV method. We found that PGLa forms nanopores in the GUV membrane, which evolved into a local burst and burst of GUVs. The rate of pore formation in DOPE/DOPG-GUVs was smaller than that in DOPC/DOPG-GUVs. PGLa is located only in the outer leaflet of a GUV bilayer just before a fluorescent probe AF647 leakage from the inside, indicating that this asymmetric distribution induces nanopore formation. PGLa-induced local burst and burst of GUVs were observed at 10 ms-time resolution. After nanopore formation started, dense particles and small vesicles appeared in the GUVs, followed by a decrease in the GUV diameter. The GUV was finally converted into smaller GUV or lipid membrane aggregates. We discuss the mechanisms of PGLa-induced nanopore formation and its direct evolution to a GUV burst.
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Affiliation(s)
- Marzuk Ahmed
- Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
| | - Md Zahidul Islam
- Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka 422-8529, Japan
| | - Md Masum Billah
- Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
| | - Masahito Yamazaki
- Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
- Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka 422-8529, Japan
- Department of Physics, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan
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Pushpa Ragini S, White J, Kirby N, Banerjee R, Reddy Bathula S, Drummond CJ, Conn CE. Novel bioactive cationic cubosomes enhance the cytotoxic effect of paclitaxel against a paclitaxel resistant prostate cancer cell-line. J Colloid Interface Sci 2023; 649:966-976. [PMID: 37392686 DOI: 10.1016/j.jcis.2023.06.122] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 06/05/2023] [Accepted: 06/17/2023] [Indexed: 07/03/2023]
Abstract
Hypothesis The study aimed to use molecular hybridization of a cationic lipid with a known pharmacophore to produce a bifunctional lipid having a cationic charge to enhance fusion with the cancer cell surface and biological activity via the pharmacophoric head group. Experiments The novel cationic lipid DMP12 [N-(2-(3-(3,4-dimethoxyphenyl) propanamido) ethyl)-N-dodecyl-N-methyldodecan-1-aminium iodide] was synthesised by conjugating 3-(3,4-dimethoxyphenyl) propanoic acid (or 3,4-dimethoxyhydrocinnamic acid) to twin 12 carbon chains bearing a quaternary ammonium group [N-(2-aminoethyl)-N-dodecyl-N-methyldodecan-1-aminium iodide]. The physicochemical and biological properties of DMP12 were investigated. Cubosome particles consisting of monoolein (MO) doped with DMP12 and paclitaxel were characterized using Small-angle X-ray Scattering (SAXS), Dynamic Light Scattering (DLS), and Cryo-Transmission Electron Microscopy (Cryo-TEM). Combination therapy using these cubosomes was assessed in vitro against the gastric (AGS) and prostate (DU-145 and PC-3) cancer cell lines using cytotoxicity assay. Findings Monoolein (MO) cubosomes doped with DMP12 were observed to be toxic against the AGS and DU-145 cell-lines at higher cubosome concentrations (≥100 µg/ml) but had limited activity against the PC-3 cell-line. However, combination therapy consisting of 5 mol% DMP12 and 0.5 mol% paclitaxel (PTX) significantly increased the cytotoxicity against the PC-3 cell-line which was resistant to either DMP12 or PTX individually. The results demonstrate that DMP12 has a prospective role as a bioactive excipient in cancer therapy.
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Affiliation(s)
- S Pushpa Ragini
- Department of Oils, lipids science and technology, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India; Academy of Scientific and Innovation Research (AcSIR), Ghaziabad, 201002, India; Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad-500007, India; School of Science, College of Science, Engineering and Health, RMIT University, Melbourne 3000, Victoria, Australia
| | - Jacinta White
- CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3168, Australia
| | - Nigel Kirby
- Australian Synchrotron, 800 Blackburn Rd, Clayton, VIC 3168, Australia
| | - Rajkumar Banerjee
- Department of Oils, lipids science and technology, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India; Academy of Scientific and Innovation Research (AcSIR), Ghaziabad, 201002, India
| | - Surendar Reddy Bathula
- Academy of Scientific and Innovation Research (AcSIR), Ghaziabad, 201002, India; Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad-500007, India
| | - Calum J Drummond
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne 3000, Victoria, Australia
| | - Charlotte E Conn
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne 3000, Victoria, Australia.
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Sarkar S, Mishra A, Periasamy S, Dyett B, Dogra P, Ball AS, Yeo LY, White JF, Wang Z, Cristini V, Jagannath C, Khan A, Soni SK, Drummond CJ, Conn CE. Prospective Subunit Nanovaccine against Mycobacterium tuberculosis Infection─Cubosome Lipid Nanocarriers of Cord Factor, Trehalose 6,6' Dimycolate. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37262346 DOI: 10.1021/acsami.3c04063] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
An improved vaccine is urgently needed to replace the now more than 100-year-old Bacillus Calmette-Guérin (BCG) vaccine against tuberculosis (TB) disease, which represents a significant burden on global public health. Mycolic acid, or cord factor trehalose 6,6' dimycolate (TDM), a lipid component abundant in the cell wall of the pathogen Mycobacterium tuberculosis (MTB), has been shown to have strong immunostimulatory activity but remains underexplored due to its high toxicity and poor solubility. Herein, we employed a novel strategy to encapsulate TDM within a cubosome lipid nanocarrier as a potential subunit nanovaccine candidate against TB. This strategy not only increased the solubility and reduced the toxicity of TDM but also elicited a protective immune response to control MTB growth in macrophages. Both pre-treatment and concurrent treatment of the TDM encapsulated in lipid monoolein (MO) cubosomes (MO-TDM) (1 mol %) induced a strong proinflammatory cytokine response in MTB-infected macrophages, due to epigenetic changes at the promoters of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) in comparison to the untreated control. Furthermore, treatment with MO-TDM (1 mol %) cubosomes significantly improved antigen processing and presentation capabilities of MTB-infected macrophages to CD4 T cells. The ability of MO-TDM (1 mol %) cubosomes to induce a robust innate and adaptive response in vitro was further supported by a mathematical modeling study predicting the vaccine efficacy in vivo. Overall, these results indicate a strong immunostimulatory effect of TDM when delivered through the lipid nanocarrier, suggesting its potential as a novel TB vaccine.
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Affiliation(s)
- Sampa Sarkar
- School of Science, STEM College, RMIT University, Melbourne 3001, Victoria, Australia
| | - Abhishek Mishra
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, Texas 77030, United States
| | - Selvakannan Periasamy
- School of Science, STEM College, RMIT University, Melbourne 3001, Victoria, Australia
| | - Brendan Dyett
- School of Science, STEM College, RMIT University, Melbourne 3001, Victoria, Australia
| | - Prashant Dogra
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas 77030, United States
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York 10021, United States
| | - Andrew S Ball
- School of Science, STEM College, RMIT University, Melbourne 3001, Victoria, Australia
| | - Leslie Y Yeo
- School of Engineering, STEM College, RMIT University, Melbourne 3001, Victoria, Australia
| | - Jacinta F White
- The Commonwealth Scientific and Industrial Research Organisation, Clayton 3169, Victoria, Australia
| | - Zhihui Wang
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas 77030, United States
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York 10021, United States
- Neal Cancer Center, Houston Methodist Research Institute, Houston, Texas 77030, United States
| | - Vittorio Cristini
- Mathematics in Medicine Program, Houston Methodist Research Institute, Houston, Texas 77030, United States
- Neal Cancer Center, Houston Methodist Research Institute, Houston, Texas 77030, United States
- Department of Imaging Physics, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, United States
- Physiology, Biophysics, and Systems Biology Program, Graduate School of Medical Sciences, Weill Cornell Medicine, New York, New York 10021, United States
| | - Chinnaswamy Jagannath
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, Texas 77030, United States
| | - Arshad Khan
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, Texas 77030, United States
| | - Sarvesh K Soni
- School of Science, STEM College, RMIT University, Melbourne 3001, Victoria, Australia
| | - Calum J Drummond
- School of Science, STEM College, RMIT University, Melbourne 3001, Victoria, Australia
| | - Charlotte E Conn
- School of Science, STEM College, RMIT University, Melbourne 3001, Victoria, Australia
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5
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Tazawa K, Yamazaki M. Effect of monolayer spontaneous curvature on constant tension-induced pore formation in lipid bilayers. J Chem Phys 2023; 158:081101. [PMID: 36859073 DOI: 10.1063/5.0135561] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The methodology of constant tension-induced rupture of giant unilamellar vesicles (GUVs) has provided information on tension-induced pore formation. This method was used to investigate the effect of spontaneous curvature (H0) for a lipid monolayer on the rate constant (kr) for constant tension (σ)-induced rupture, which originates from pore formation in lipid bilayers. Lipids were incorporated with different H0 values into GUV membranes to change the overall H0 value for the GUV monolayer. The dioleoylphosphatidylglycerol (DOPG)/dioleoylphosphatidylethanolamine (DOPE) (4/6, molar ratio, here and elsewhere) monolayer has a negative H0, whereas the DOPG/dioleoylphosphatidylcholine (DOPC) (4/6) monolayer has an essentially zero H0. A higher tension was required to induce the rupture of DOPG/DOPE (4/6)-GUVs compared with DOPG/DOPC (4/6)-GUVs. The line tension (Γ) for a pre-pore in DOPG/DOPE (4/6)-GUVs, determined by the analysis of the tension dependence of kr, was 1.5 times larger than that in DOPG/DOPC (4/6)-GUVs. The kr values for GUVs comprising DOPG/DOPC/18:1 lysophosphatidylcholine (LPC) (40/55/10), which has a positive H0, were larger than those for DOPG/DOPC (4/6)-GUVs under the same tension. The Γ value for DOPG/DOPC/LPC (40/55/10)-GUVs was almost half that for DOPG/DOPC (4/6)-GUVs. These results indicate that Γ decreases with increasing H0, which results in an increase in kr. Based on these results, the effect of H0 on kr and Γ is discussed.
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Affiliation(s)
- Kanta Tazawa
- Physics Course, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
| | - Masahito Yamazaki
- Physics Course, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
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6
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Mannsverk S, Villamil Giraldo AM, Kasson PM. Influenza Virus Membrane Fusion Is Promoted by the Endosome-Resident Phospholipid Bis(monoacylglycero)phosphate. J Phys Chem B 2022; 126:10445-10451. [PMID: 36468619 PMCID: PMC9761668 DOI: 10.1021/acs.jpcb.2c06642] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The phospholipid bis(monoacylglycero)phosphate (BMP) is enriched in late endosomal and endolysosomal membranes and is believed to be involved in membrane deformation and generation of intralumenal vesicles within late endosomes. Previous studies have demonstrated that BMP promotes membrane fusion of several enveloped viruses, but a limited effect has been found on influenza virus. Here, we report the use of single-virus fusion assays to dissect BMP's effect on influenza virus fusion in greater depth. In agreement with prior reports, we found that hemifusion kinetics and efficiency were unaffected by the addition of 10-20 mol % BMP to the target membrane. However, using an assay for fusion pore formation and genome exposure, we found full fusion efficiency to be substantially enhanced by the addition of 10-20 mol % BMP to the target membrane, while the kinetics remained unaffected. By comparing BMP to other negatively charged phospholipids, we found the effect on fusion efficiency mainly attributable to headgroup charge, although we also hypothesize a role for BMP's unusual chemical structure. Our results suggest that BMP function as a permissive factor for a wider range of viruses than previously reported. We hypothesize that BMP may be a general cofactor for endosomal entry of enveloped viruses.
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Affiliation(s)
- Steinar Mannsverk
- Science
for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala 75124, Sweden
| | - Ana M. Villamil Giraldo
- Science
for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala 75124, Sweden
| | - Peter M. Kasson
- Science
for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala 75124, Sweden,Departments
of Molecular Physiology and Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, United States,
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7
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Vítová M, Lanta V, Čížková M, Jakubec M, Rise F, Halskau Ø, Bišová K, Furse S. The biosynthesis of phospholipids is linked to the cell cycle in a model eukaryote. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158965. [PMID: 33992808 PMCID: PMC8202326 DOI: 10.1016/j.bbalip.2021.158965] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 12/15/2022]
Abstract
The structural challenges faced by eukaryotic cells through the cell cycle are key for understanding cell viability and proliferation. We tested the hypothesis that the biosynthesis of structural lipids is linked to the cell cycle. If true, this would suggest that the cell's structure is important for progress through and perhaps even control of the cell cycle. Lipidomics (31P NMR and MS), proteomics (Western immunoblotting) and transcriptomics (RT-qPCR) techniques were used to profile the lipid fraction and characterise aspects of its metabolism at seven stages of the cell cycle of the model eukaryote, Desmodesmus quadricauda. We found considerable, transient increases in the abundance of phosphatidylethanolamine during the G1 phase (+35%, ethanolamine phosphate cytidylyltransferase increased 2·5×) and phosphatidylglycerol (+100%, phosphatidylglycerol synthase increased 22×) over the G1/pre-replication phase boundary. The relative abundance of phosphatidylcholine fell by ~35% during the G1. N-Methyl transferases for the conversion of phosphatidylethanolamine into phosphatidylcholine were not found in the de novo transcriptome profile, though a choline phosphate transferase was found, suggesting that the Kennedy pathway is the principal route for the synthesis of PC. The fatty acid profiles of the four most abundant lipids suggested that these lipids were not generally converted between one another. This study shows for the first time that there are considerable changes in the biosynthesis of the three most abundant phospholipid classes in the normal cell cycle of D. quadricauda, by margins large enough to elicit changes to the physical properties of membranes.
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Affiliation(s)
- Milada Vítová
- Laboratory of Cell Cycles of Algae (Laboratoř buněčných cyklů řas), Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Novohradská 237, 379 01 Třeboň, Czech Republic
| | - Vojtěch Lanta
- Laboratory of Cell Cycles of Algae (Laboratoř buněčných cyklů řas), Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Novohradská 237, 379 01 Třeboň, Czech Republic; Department of Functional Ecology, Institute of Botany of the Czech Academy of Sciences, Dukelská 135, 379 81 Třeboň, Czech Republic
| | - Mária Čížková
- Laboratory of Cell Cycles of Algae (Laboratoř buněčných cyklů řas), Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Novohradská 237, 379 01 Třeboň, Czech Republic
| | - Martin Jakubec
- Department of Molecular Biology, University of Bergen, Thormøhlens gate 55, NO-5008 Bergen, Norway
| | - Frode Rise
- Department of Chemistry, Universitetet i Oslo, P. O. Box 1033, Blindern, NO-0315 Oslo, Norway
| | - Øyvind Halskau
- Department of Molecular Biology, University of Bergen, Thormøhlens gate 55, NO-5008 Bergen, Norway
| | - Kateřina Bišová
- Laboratory of Cell Cycles of Algae (Laboratoř buněčných cyklů řas), Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Novohradská 237, 379 01 Třeboň, Czech Republic
| | - Samuel Furse
- Department of Molecular Biology, University of Bergen, Thormøhlens gate 55, NO-5008 Bergen, Norway; Core Metabolomics and Lipidomics Laboratory, Wellcome Trust-MRL Institute of Metabolic Science, University of Cambridge, Level 4, Pathology Building, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom; Biological chemistry group, Jodrell laboratory, Royal Botanic Gardens Kew, United Kingdom.
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8
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Kaltenegger M, Kremser J, Frewein MPK, Ziherl P, Bonthuis DJ, Pabst G. Intrinsic lipid curvatures of mammalian plasma membrane outer leaflet lipids and ceramides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183709. [PMID: 34332987 DOI: 10.1016/j.bbamem.2021.183709] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/16/2021] [Accepted: 07/20/2021] [Indexed: 01/26/2023]
Abstract
We developed a global X-ray data analysis method to determine the intrinsic curvatures of lipids hosted in inverted hexagonal phases. In particular, we combined compositional modelling with molecular shape-based arguments to account for non-linear mixing effects of guest-in-host lipids on intrinsic curvature. The technique was verified by all-atom molecular dynamics simulations and applied to sphingomyelin and a series of phosphatidylcholines and ceramides with differing composition of the hydrocarbon chains. We report positive lipid curvatures for sphingomyelin and all phosphatidylcholines with disaturated and monounsaturated hydrocarbons. Phosphatidylcholines with diunsaturated hydrocarbons in turn yielded intrinsic lipid curvatures with negative values. All ceramides, with chain lengths varying between C2:0 and C24:0, displayed significant negative lipid curvature values. Moreover, we report non-additive mixing for C2:0 ceramide and sphingomyelin. This suggests for sphingolipids that in addition to lipid headgroup and hydrocarbon chain volumes also lipid-specific interactions are important contributors to membrane curvature stress.
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Affiliation(s)
- Michael Kaltenegger
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Johannes Kremser
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Moritz P K Frewein
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria; Institut Laue-Langevin, 38043 Grenoble, France
| | - Primož Ziherl
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia; Jožef Stefan Institute, Ljubljana, Slovenia
| | - Douwe J Bonthuis
- Graz University of Technology, Institute of Theoretical and Computational Physics, NAWI Graz, 8010 Graz, Austria
| | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria; BioTechMed Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria.
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9
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Dymond MK. Lipid monolayer spontaneous curvatures: A collection of published values. Chem Phys Lipids 2021; 239:105117. [PMID: 34265278 DOI: 10.1016/j.chemphyslip.2021.105117] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 07/03/2021] [Accepted: 07/09/2021] [Indexed: 11/24/2022]
Abstract
Lipid monolayer spontaneous curvatures (or lipid intrinsic curvatures) are one of several material properties of lipids that enable the stored curvature elastic energy in a lipid aggregate to be determined. Stored curvature elastic energy is important since it can modulate the function of membrane proteins and plays a role in the regulatory pathways of phospholipid homeostasis. Due to the large number of different lipid molecules that might theoretically exist in nature, very few lipid spontaneous curvatures have been determined. Herein the values of lipid spontaneous curvatures that exist in the literature are collected, alongside key experimental details. Where possible, trends in the data are discussed and finally, obvious gaps in the knowledge are signposted.
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Affiliation(s)
- Marcus K Dymond
- Chemistry Research and Enterprise Group, School of Pharmacy and Biomolecular Sciences, Huxley Building, University of Brighton, BN2 4GL, United Kingdom.
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10
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Semeraro EF, Marx L, Frewein MPK, Pabst G. Increasing complexity in small-angle X-ray and neutron scattering experiments: from biological membrane mimics to live cells. SOFT MATTER 2021; 17:222-232. [PMID: 32104874 DOI: 10.1039/c9sm02352f] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Small-angle X-ray and neutron scattering are well-established, non-invasive experimental techniques to interrogate global structural properties of biological membrane mimicking systems under physiologically relevant conditions. Recent developments, both in bottom-up sample preparation techniques for increasingly complex model systems, and in data analysis techniques have opened the path toward addressing long standing issues of biological membrane remodelling processes. These efforts also include emerging quantitative scattering studies on live cells, thus enabling a bridging of molecular to cellular length scales. Here, we review recent progress in devising compositional models for joint small-angle X-ray and neutron scattering studies on diverse membrane mimics - with a specific focus on membrane structural coupling to amphiphatic peptides and integral proteins - and live Escherichia coli. In particular, we outline the present state-of-the-art in small-angle scattering methods applied to complex membrane systems, highlighting how increasing system complexity must be followed by an advance in compositional modelling and data-analysis tools.
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Affiliation(s)
- Enrico F Semeraro
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria. and BioTechMed Graz, 8010 Graz, Austria
| | - Lisa Marx
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria. and BioTechMed Graz, 8010 Graz, Austria
| | - Moritz P K Frewein
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria. and BioTechMed Graz, 8010 Graz, Austria and Institut Laue-Langevin, 38000 Grenoble, France
| | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria. and BioTechMed Graz, 8010 Graz, Austria
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11
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Sarkar S, Tran N, Soni SK, Nasa Z, Drummond CJ, Conn CE. Cuboplex-Mediated Nonviral Delivery of Functional siRNA to Chinese Hamster Ovary (CHO) Cells. ACS APPLIED MATERIALS & INTERFACES 2021; 13:2336-2345. [PMID: 33410653 DOI: 10.1021/acsami.0c20956] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Lipid nanoparticles of internal cubic symmetry, termed cuboplexes, are potential nonviral delivery vehicles for gene therapy due to their "topologically active" nature, which may enhance endosomal escape and improve delivery outcomes. In this study, we have used cationic cuboplexes, based on monoolein (MO) doped with a cationic lipid, for the encapsulation and delivery of antisense green fluorescent protein (GFP)-small interfering RNA (siRNA) into Chinese Hamster Ovary (CHO)-GFP cells. Agarose gel electrophoresis has confirmed the successful encapsulation of siRNA within cationic cubosomes, while synchrotron small-angle X-ray scattering (SAXS) demonstrated that the underlying cubic nanostructure of the particles was retained following encapsulation. The cationic cubosomes were shown to be reasonably nontoxic against the CHO-GFP cell line. Fluorescence-activated cell sorting (FACS) provided evidence of the successful transfection to CHO-GFP cells. Knockdown efficiency was strongly linked to the type of cationic lipid used, although all cubosomes had essentially the same internal nanostructure. The gene knockdown efficiency for some cationic cubosomes was shown to be higher than lipofectamine, which is a commercially available liposome-based formulation, while the controlled release of the siRNA from the cubosomes over a 72 h period was observed using confocal microscopy. This combination exemplifies the potential of cationic cuboplexes as a novel, nonviral, controlled-release delivery vector for siRNA.
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Affiliation(s)
- Sampa Sarkar
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3000, Australia
| | - Nhiem Tran
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3000, Australia
| | - Sarvesh Kumar Soni
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3000, Australia
| | - Zeyad Nasa
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3000, Australia
| | - Calum J Drummond
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3000, Australia
| | - Charlotte E Conn
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3000, Australia
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12
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Toxicity and cellular uptake of lipid nanoparticles of different structure and composition. J Colloid Interface Sci 2020; 576:241-251. [DOI: 10.1016/j.jcis.2020.05.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/29/2020] [Accepted: 05/01/2020] [Indexed: 12/13/2022]
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13
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Elmer-Dixon MM, Hoody J, Steele HBB, Becht DC, Bowler BE. Cardiolipin Preferentially Partitions to the Inner Leaflet of Mixed Lipid Large Unilamellar Vesicles. J Phys Chem B 2019; 123:9111-9122. [DOI: 10.1021/acs.jpcb.9b07690] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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14
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Zhukovsky MA, Filograna A, Luini A, Corda D, Valente C. Phosphatidic acid in membrane rearrangements. FEBS Lett 2019; 593:2428-2451. [PMID: 31365767 DOI: 10.1002/1873-3468.13563] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 12/16/2022]
Abstract
Phosphatidic acid (PA) is the simplest cellular glycerophospholipid characterized by unique biophysical properties: a small headgroup; negative charge; and a phosphomonoester group. Upon interaction with lysine or arginine, PA charge increases from -1 to -2 and this change stabilizes protein-lipid interactions. The biochemical properties of PA also allow interactions with lipids in several subcellular compartments. Based on this feature, PA is involved in the regulation and amplification of many cellular signalling pathways and functions, as well as in membrane rearrangements. Thereby, PA can influence membrane fusion and fission through four main mechanisms: it is a substrate for enzymes producing lipids (lysophosphatidic acid and diacylglycerol) that are involved in fission or fusion; it contributes to membrane rearrangements by generating negative membrane curvature; it interacts with proteins required for membrane fusion and fission; and it activates enzymes whose products are involved in membrane rearrangements. Here, we discuss the biophysical properties of PA in the context of the above four roles of PA in membrane fusion and fission.
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Affiliation(s)
- Mikhail A Zhukovsky
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Angela Filograna
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Alberto Luini
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Daniela Corda
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Protein Biochemistry and Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
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15
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Leber R, Pachler M, Kabelka I, Svoboda I, Enkoller D, Vácha R, Lohner K, Pabst G. Synergism of Antimicrobial Frog Peptides Couples to Membrane Intrinsic Curvature Strain. Biophys J 2019; 114:1945-1954. [PMID: 29694871 PMCID: PMC5937145 DOI: 10.1016/j.bpj.2018.03.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/07/2018] [Accepted: 03/12/2018] [Indexed: 01/11/2023] Open
Abstract
Mixtures of the frog peptides magainin 2 and PGLa are well-known for their pronounced synergistic killing of Gram-negative bacteria. We aimed to gain insight into the underlying biophysical mechanism by interrogating the permeabilizing efficacies of the peptides as a function of stored membrane curvature strain. For Gram-negative bacterial-inner-membrane mimics, synergism was only observed when the anionic bilayers exhibited significant negative intrinsic curvatures imposed by monounsaturated phosphatidylethanolamine. In contrast, the peptides and their mixtures did not exhibit significant activities in charge-neutral mammalian mimics, including those with negative curvature, which is consistent with the requirement of charge-mediated peptide binding to the membrane. Our experimental findings are supported by computer simulations showing a significant decrease of the peptide-insertion free energy in membranes upon shifting intrinsic curvatures toward more positive values. The physiological relevance of our model studies is corroborated by a remarkable agreement with the peptide’s synergistic activity in Escherichia coli. We propose that synergism is related to a lowering of a membrane-curvature-strain-mediated free-energy barrier by PGLa that assists membrane insertion of magainin 2, and not by strict pairwise interactions of the two peptides as suggested previously.
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Affiliation(s)
- Regina Leber
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Michael Pachler
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Ivo Kabelka
- Central European Institute of Technology, Brno, Czech Republic; Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Irene Svoboda
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | | | - Robert Vácha
- Central European Institute of Technology, Brno, Czech Republic; Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria.
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16
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Mescola A, Marín-Medina N, Ragazzini G, Accolla M, Alessandrini A. Magainin-H2 effects on the permeabilization and mechanical properties of giant unilamellar vesicles. J Colloid Interface Sci 2019; 553:247-258. [PMID: 31207545 DOI: 10.1016/j.jcis.2019.06.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/28/2019] [Accepted: 06/09/2019] [Indexed: 10/26/2022]
Abstract
Among the potential novel therapeutics to treat bacterial infections, antimicrobial peptides (AMPs) are a very promising substitute due to their broad-spectrum activity and rapid bactericidal action. AMPs strongly interact with the bacterial membrane, and the need to have a correct understanding of the interaction between AMPs and lipid bilayers at a molecular level prompted a wealth of experimental and theoretical studies exploiting a variety of AMPs. Here, we studied the effects of magainin H2 (Mag H2), an analog of the well-known magainin 2 (wt Mag 2) AMP endowed with a higher degree of hydrophobicity, on giant unilamellar vesicles (GUVs) concentrating on its permeabilization activity and the effect on the lipid bilayer mechanical properties. We demonstrated that the increased hydrophobicity of Mag H2 affects its selectivity conferring a strong permeabilization activity also on zwitterionic lipid bilayers. Moreover, when lipid mixtures including PG lipids are considered, PG has a protective effect, at variance from wt Mag 2, suggesting that for Mag H2 the monolayer curvature could prevail over the peptide-membrane electrostatic interaction. We then mechanically characterized GUVs by measuring the effect of Mag H2 on the bending constant of lipid bilayers by flickering spectroscopy and, by using micropipette aspiration technique, we followed the steps leading to vesicle permeabilization. We found that Mag H2, notwithstanding its enhanced hydrophobicity, has a pore formation mechanism compatible with the toroidal pore model similar to that of wt Mag 2.
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Affiliation(s)
- Andrea Mescola
- CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy.
| | - Nathaly Marín-Medina
- Department of Physics, University of Los Andes, Carrera 1 N° 18A - 12, Bogotá, Colombia.
| | - Gregorio Ragazzini
- CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy; Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy.
| | - Maurizio Accolla
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy
| | - Andrea Alessandrini
- CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy; Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy.
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17
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Frewein MPK, Rumetshofer M, Pabst G. Global small-angle scattering data analysis of inverted hexagonal phases. J Appl Crystallogr 2019; 52:403-414. [PMID: 30996718 PMCID: PMC6448687 DOI: 10.1107/s1600576719002760] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/23/2019] [Indexed: 11/29/2022] Open
Abstract
A global small-angle scattering model for unoriented, fully hydrated, inverted hexagonal phases is provided. The model is evaluated using Bayesian probability theory to obtain reliable estimates for the structural parameters. A global analysis model has been developed for randomly oriented, fully hydrated, inverted hexagonal (HII) phases formed by many amphiphiles in aqueous solution, including membrane lipids. The model is based on a structure factor for hexagonally packed rods and a compositional model for the scattering length density, enabling also the analysis of positionally weakly correlated HII phases. Bayesian probability theory was used for optimization of the adjustable parameters, which allows parameter correlations to be retrieved in much more detail than standard analysis techniques and thereby enables a realistic error analysis. The model was applied to different phosphatidylethanolamines, including previously unreported HII data for diC14:0 and diC16:1 phosphatidylethanolamine. The extracted structural features include intrinsic lipid curvature, hydrocarbon chain length and area per lipid at the position of the neutral plane.
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Affiliation(s)
- Moritz P K Frewein
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria.,BioTechMed Graz, 8010 Graz, Austria
| | - Michael Rumetshofer
- Graz University of Technology, Institute of Theoretical Physics and Computational Physics, NAWI Graz, 8010 Graz, Austria
| | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, 8010 Graz, Austria.,BioTechMed Graz, 8010 Graz, Austria
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18
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Ewins E, Lira RB, Zhang W, Yuan J, Antonietti M, Robinson T, Dimova R. Poly(Ionic Liquid) Nanoparticles Selectively Disrupt Biomembranes. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1801602. [PMID: 30828532 PMCID: PMC6382306 DOI: 10.1002/advs.201801602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/29/2018] [Indexed: 06/09/2023]
Abstract
Polymer-based nanoparticles have an increasing presence in research due to their attractive properties, such as flexible surface functionality design and the ability to scale up production. Poly(ionic liquid) (PIL) nanoparticles of size below 50 nm are very unique in terms of their high charge density and internal onion-like morphology. The interaction between PIL nanoparticles and giant unilamellar vesicles (GUVs) of various surface charge densities is investigated. GUVs represent a convenient model system as they mimic the size and curvature of plasma membranes, while simultaneously offering direct visualization of the membrane response under the microscope. Incubating PIL nanoparticles with GUVs results in poration of the lipid membrane in a concentration- and charge-dependent manner. A critical poration concentration of PILs is located and the interactions are found to be analogous to those of antimicrobial peptides. Microbial mimetic membranes are already affected at submicromolar PIL concentrations where contrast loss is observed due to sugar exchange across the membrane, while at high concentrations the collapse of vesicles is observed. Finally, a confocal microscopy-based approach assessing the particle permeation through the membrane is reported and a mechanism based on bilayer frustration and pore stabilization via particle integration in the membrane is proposed.
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Affiliation(s)
- Eleanor Ewins
- Department of Theory & Bio‐SystemsMax Planck Institute of Colloids and InterfacesScience Park Golm14424PotsdamGermany
| | - Rafael B. Lira
- Department of Theory & Bio‐SystemsMax Planck Institute of Colloids and InterfacesScience Park Golm14424PotsdamGermany
| | - Weiyi Zhang
- Department of Colloid ChemistryMax Planck Institute of Colloids and InterfacesScience Park Golm14424PotsdamGermany
| | - Jiayin Yuan
- Department of Colloid ChemistryMax Planck Institute of Colloids and InterfacesScience Park Golm14424PotsdamGermany
| | - Markus Antonietti
- Department of Colloid ChemistryMax Planck Institute of Colloids and InterfacesScience Park Golm14424PotsdamGermany
| | - Tom Robinson
- Department of Theory & Bio‐SystemsMax Planck Institute of Colloids and InterfacesScience Park Golm14424PotsdamGermany
| | - Rumiana Dimova
- Department of Theory & Bio‐SystemsMax Planck Institute of Colloids and InterfacesScience Park Golm14424PotsdamGermany
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19
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Barlow NE, Kusumaatmaja H, Salehi-Reyhani A, Brooks N, Barter LMC, Flemming AJ, Ces O. Measuring bilayer surface energy and curvature in asymmetric droplet interface bilayers. J R Soc Interface 2018; 15:rsif.2018.0610. [PMID: 30464059 PMCID: PMC6283991 DOI: 10.1098/rsif.2018.0610] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/23/2018] [Indexed: 11/12/2022] Open
Abstract
For the past decade, droplet interface bilayers (DIBs) have had an increased prevalence in biomolecular and biophysical literature. However, much of the underlying physics of these platforms is poorly characterized. To further our understanding of these structures, lipid membrane tension on DIB membranes is measured by analysing the equilibrium shape of asymmetric DIBs. To this end, the morphology of DIBs is explored for the first time using confocal laser scanning fluorescence microscopy. The experimental results confirm that, in accordance with theory, the bilayer interface of a volume-asymmetric DIB is curved towards the smaller droplet and a lipid-asymmetric DIB is curved towards the droplet with the higher monolayer surface tension. Moreover, the DIB shape can be exploited to measure complex bilayer surface energies. In this study, the bilayer surface energy of DIBs composed of lipid mixtures of phosphatidylgylcerol (PG) and phosphatidylcholine are shown to increase linearly with PG concentrations up to 25%. The assumption that DIB bilayer area can be geometrically approximated as a spherical cap base is also tested, and it is discovered that the bilayer curvature is negligible for most practical symmetric or asymmetric DIB systems with respect to bilayer area.
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Affiliation(s)
- Nathan E Barlow
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK.,Institute of Chemical Biology, Imperial College London, London SW7 2AZ, UK
| | - Halim Kusumaatmaja
- Department of Physics, Durham University, South Road, Durham DH1 3LE, UK
| | - Ali Salehi-Reyhani
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK.,Institute of Chemical Biology, Imperial College London, London SW7 2AZ, UK.,FABRICELL, Imperial College London, London SW7 2AZ, UK
| | - Nick Brooks
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK.,Institute of Chemical Biology, Imperial College London, London SW7 2AZ, UK
| | - Laura M C Barter
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK.,Institute of Chemical Biology, Imperial College London, London SW7 2AZ, UK
| | - Anthony J Flemming
- Syngenta, Jealott's Hill International Research Centre, Bracknell RG42 6EY, UK
| | - Oscar Ces
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK .,Institute of Chemical Biology, Imperial College London, London SW7 2AZ, UK.,FABRICELL, Imperial College London, London SW7 2AZ, UK
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20
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Xing X, Ma W, Zhao X, Wang J, Yao L, Jiang X, Wu Z. Interaction between Surface Charge-Modified Gold Nanoparticles and Phospholipid Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:12583-12589. [PMID: 30239201 DOI: 10.1021/acs.langmuir.8b01700] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
This report clarifies the interaction of surface charge-modified gold nanoparticles (AuNPs) with phospholipid membranes, which is helpful to understand the antibacterial mechanism of positive charge-modified AuNPs to Gram-negative bacteria. Although the simulated bacterial cell membranes as a whole are negatively charged, the local electrostatic repulsive interaction between the positive charge-coated AuNPs and the small-sized flexible cationic head group of dioleyl phosphatidylethanolamine molecules induces the phase transformation of the simulated bacterial cell membranes from a lamellar to an inverted hexagonal phase. Transmembrane pores with a diameter of about 3.0 nm in the inverted hexagonal structure would result in the destruction of cell membrane function. Such an interaction of positive charge-modified AuNPs with the membrane mimics provides a promising route to develop new antibacterial agents by modifying positive charges on the surface of nanoparticles.
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Affiliation(s)
- Xueqing Xing
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
| | - Wanshun Ma
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety , National Center for NanoScience and Technology , Beijing 100190 , China
| | - Xiaoyi Zhao
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Jiayi Wang
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Lei Yao
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
| | - Xingyu Jiang
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety , National Center for NanoScience and Technology , Beijing 100190 , China
| | - Zhonghua Wu
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
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21
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Lipids modulate the insertion and folding of the nascent chains of alpha helical membrane proteins. Biochem Soc Trans 2018; 46:1355-1366. [PMID: 30190329 DOI: 10.1042/bst20170424] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/18/2018] [Accepted: 07/31/2018] [Indexed: 02/08/2023]
Abstract
Membrane proteins must be inserted into a membrane and folded into their correct structure to function correctly. This insertion occurs during translation and synthesis by the ribosome for most α-helical membrane proteins. Precisely how this co-translational insertion and folding occurs, and the role played by the surrounding lipids, is still not understood. Most of the work on the influence of the lipid environment on folding and insertion has focussed on denatured, fully translated proteins, and thus does not replicate folding during unidirectional elongation of nascent chains that occurs in the cell. This review aims to highlight recent advances in elucidating lipid composition and bilayer properties optimal for insertion and folding of nascent chains in the membrane and in the assembly of oligomeric proteins.
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22
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Barragán Vidal IA, Müller M. Generalization of the swelling method to measure the intrinsic curvature of lipids. J Chem Phys 2017; 147:224902. [PMID: 29246037 DOI: 10.1063/1.5001858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Via computer simulation of a coarse-grained model of two-component lipid bilayers, we compare two methods of measuring the intrinsic curvatures of the constituting monolayers. The first one is a generalization of the swelling method that, in addition to the assumption that the spontaneous curvature linearly depends on the composition of the lipid mixture, incorporates contributions from its elastic energy. The second method measures the effective curvature-composition coupling between the apposing leaflets of bilayer structures (planar bilayers or cylindrical tethers) to extract the spontaneous curvature. Our findings demonstrate that both methods yield consistent results. However, we highlight that the two-leaflet structure inherent to the latter method has the advantage of allowing measurements for mixed lipid systems up to their critical point of demixing as well as in the regime of high concentration (of either species).
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Affiliation(s)
- I A Barragán Vidal
- Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - M Müller
- Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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23
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The folding, stability and function of lactose permease differ in their dependence on bilayer lipid composition. Sci Rep 2017; 7:13056. [PMID: 29026149 PMCID: PMC5638818 DOI: 10.1038/s41598-017-13290-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/19/2017] [Indexed: 11/22/2022] Open
Abstract
Lipids play key roles in Biology. Mechanical properties of the lipid bilayer influence their neighbouring membrane proteins, however it is unknown whether different membrane protein properties have the same dependence on membrane mechanics, or whether mechanics are tuned to specific protein processes of the protein. We study the influence of lipid lateral pressure and electrostatic effects on the in vitro reconstitution, folding, stability and function of a representative of the ubiquitous major facilitator transporter superfamily, lactose permease. Increasing the outward chain lateral pressure in the bilayer, through addition of lamellar phosphatidylethanolamine lipids, lowers lactose permease folding and reconstitution yields but stabilises the folded state. The presence of phosphatidylethanolamine is however required for correct folding and function. An increase in headgroup negative charge through the addition of phosphatidylglycerol lipids favours protein reconstitution but is detrimental to topology and function. Overall the in vitro folding, reconstitution, topology, stability and function of lactose permease are found to have different dependences on bilayer composition. A regime of lipid composition is found where all properties are favoured, even if suboptimal. This lays ground rules for rational control of membrane proteins in nanotechnology and synthetic biology by manipulating global bilayer properties to tune membrane protein behaviour.
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24
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Furse S, Jakubec M, Rise F, Williams HE, Rees CED, Halskau Ø. Evidence that Listeria innocua modulates its membrane's stored curvature elastic stress, but not fluidity, through the cell cycle. Sci Rep 2017; 7:8012. [PMID: 28808346 PMCID: PMC5556093 DOI: 10.1038/s41598-017-06855-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 06/20/2017] [Indexed: 01/22/2023] Open
Abstract
This paper reports that the abundances of endogenous cardiolipin and phosphatidylethanolamine halve during elongation of the Gram-positive bacterium Listeria innocua. The lyotropic phase behaviour of model lipid systems that describe these modulations in lipid composition indicate that the average stored curvature elastic stress of the membrane is reduced on elongation of the cell, while the fluidity appears to be maintained. These findings suggest that phospholipid metabolism is linked to the cell cycle and that changes in membrane composition can facilitate passage to the succeding stage of the cell cycle. This therefore suggests a means by which bacteria can manage the physical properties of their membranes through the cell cycle.
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Affiliation(s)
- Samuel Furse
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, NO-5006, Bergen, Norway
| | - Martin Jakubec
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, NO-5006, Bergen, Norway
| | - Frode Rise
- Department of Chemistry, University of Oslo, P. O. Box 1033, Blindern, NO-0315, Oslo, Norway
| | - Huw E Williams
- Centre for Biomolecular Sciences, University of Nottingham, University Park, NG7 2RD, Nottingham, United Kingdom
| | - Catherine E D Rees
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, LE12 5RD, Nottinghamshire, United Kingdom
| | - Øyvind Halskau
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, NO-5006, Bergen, Norway.
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25
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Dymond MK, Gillams RJ, Parker DJ, Burrell J, Labrador A, Nylander T, Attard GS. Lipid Spontaneous Curvatures Estimated from Temperature-Dependent Changes in Inverse Hexagonal Phase Lattice Parameters: Effects of Metal Cations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:10083-10092. [PMID: 27603198 DOI: 10.1021/acs.langmuir.6b03098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recently we reported a method for estimating the spontaneous curvatures of lipids from temperature-dependent changes in the lattice parameter of inverse hexagonal liquid crystal phases of binary lipid mixtures. This method makes use of 1,2-dioleoyl-sn-glycerol-3-phosphoethanolamine (DOPE) as a host lipid, which preferentially forms an inverse hexagonal phase to which a guest lipid of unknown spontaneous curvature is added. The lattice parameters of these binary lipid mixtures are determined by small-angle X-ray diffraction at a range of temperatures and the spontaneous curvature of the guest lipid is determined from these data. Here we report the use of this method on a wide range of lipids under different ionic conditions. We demonstrate that our method provides spontaneous curvature values for DOPE, cholesterol, and monoolein that are within the range of values reported in the literature. Anionic lipids 1,2-dioleoyl-sn-glycerol-3-phosphatidic acid (DOPA) and 1,2-dioleoyl-sn-glycerol-3-phosphoserine (DOPS) were found to exhibit spontaneous curvatures that depend on the concentration of divalent cations present in the mixtures. We show that the range of curvatures estimated experimentally for DOPA and DOPS can be explained by a series of equilibria arising from lipid-cation exchange reactions. Our data indicate a universal relationship between the spontaneous curvature of a lipid and the extent to which it affects the lattice parameter of the hexagonal phase of DOPE when it is part of a binary mixture. This universal relationship affords a rapid way of estimating the spontaneous curvatures of lipids that are expensive, only available in small amounts, or are of limited chemical stability.
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Affiliation(s)
- Marcus K Dymond
- Division of Chemistry, School of Pharmacy and Biomolecular Sciences, University of Brighton , Brighton BN2 4GJ, U.K
| | - Richard J Gillams
- Chemistry, Faculty of Natural & Environmental Sciences, University of Southampton , Southampton SO17 1BJ, U.K
| | - Duncan J Parker
- Chemistry, Faculty of Natural & Environmental Sciences, University of Southampton , Southampton SO17 1BJ, U.K
| | - Jamie Burrell
- Chemistry, Faculty of Natural & Environmental Sciences, University of Southampton , Southampton SO17 1BJ, U.K
| | - Ana Labrador
- MAX IV Laboratory, Lund University , PO Box 118, SE-221 00 Lund, Sweden
| | - Tommy Nylander
- Physical Chemistry, Lund University , PO Box 124, SE-221 00 Lund, Sweden
| | - George S Attard
- Chemistry, Faculty of Natural & Environmental Sciences, University of Southampton , Southampton SO17 1BJ, U.K
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26
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Furse S. Is phosphatidylglycerol essential for terrestrial life? J Chem Biol 2016; 10:1-9. [PMID: 28101250 DOI: 10.1007/s12154-016-0159-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 08/29/2016] [Indexed: 01/11/2023] Open
Abstract
Lipids are of increasing importance in understanding biological systems. Lipids carrying an anionic charge are noted in particular for their electrostatic interactions with both proteins and divalent cations. However, the biological, analytical, chemical and biophysical data of such species are rarely considered together, limiting our ability to assess the true role of such lipids in vivo. In this review, evidence from a range of studies about the lipid phosphatidylglycerol is considered. This evidence supports the conclusions that this lipid is ubiquitous in living systems and generally of low abundance but probably fundamental for terrestrial life. Possible reasons for this are discussed and further questions posed.
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Affiliation(s)
- Samuel Furse
- Molekylærbiologisk institutt, Unversitetet i Bergen, Thormøhlens gate 55, 5006 Bergen, Norway
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27
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Zhang L, Rajendram M, Weibel DB, Yethiraj A, Cui Q. Ionic Hydrogen Bonds and Lipid Packing Defects Determine the Binding Orientation and Insertion Depth of RecA on Multicomponent Lipid Bilayers. J Phys Chem B 2016; 120:8424-37. [PMID: 27095675 DOI: 10.1021/acs.jpcb.6b02164] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We describe a computational and experimental approach for probing the binding properties of the RecA protein at the surface of anionic membranes. Fluorescence measurements indicate that RecA behaves differently when bound to phosphatidylglycerol (PG)- and cardiolipin (CL)-containing liposomes. We use a multistage computational protocol that integrates an implicit membrane/solvent model, the highly mobile mimetic membrane model, and the full atomistic membrane model to study how different anionic lipids perturb RecA binding to the membrane. With anionic lipids studied here, the binding interface involves three key regions: the N-terminal helix, the DNA binding loop L2, and the M-M7 region. The nature of binding involves both electrostatic interactions between cationic protein residues and lipid polar/charged groups and insertion of hydrophobic residues. The L2 loop contributes more to membrane insertion than the N-terminal helix. More subtle aspects of RecA-membrane interaction are influenced by specific properties of anionic lipids. Ionic hydrogen bonds between the carboxylate group in phosphatidylserine and several lysine residues in the C-terminal region of RecA stabilize the parallel (∥) binding orientation, which is not locally stable on PG- and CL-containing membranes despite similarity in the overall charge density. Lipid packing defects, which are more prevalent in the presence of conical lipids, are observed to enhance the insertion depth of hydrophobic motifs. The computational finding that RecA binds in a similar orientation to PG- and CL-containing membranes is consistent with the fact that PG alone is sufficient to induce RecA polar localization, although CL might be more effective because of its tighter binding to RecA. The different fluorescence behaviors of RecA upon binding to PG- and CL-containing liposomes is likely due to the different structures and flexibility of the C-terminal region of RecA when it binds to different anionic phospholipids.
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Affiliation(s)
- Leili Zhang
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Manohary Rajendram
- Department of Biochemistry, University of Wisconsin-Madison , 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Douglas B Weibel
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.,Department of Biochemistry, University of Wisconsin-Madison , 433 Babcock Drive, Madison, Wisconsin 53706, United States.,Department of Biomedical Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Arun Yethiraj
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Qiang Cui
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
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28
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Lin TY, Weibel DB. Organization and function of anionic phospholipids in bacteria. Appl Microbiol Biotechnol 2016; 100:4255-67. [PMID: 27026177 DOI: 10.1007/s00253-016-7468-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/04/2016] [Accepted: 03/08/2016] [Indexed: 11/25/2022]
Abstract
In addition to playing a central role as a permeability barrier for controlling the diffusion of molecules and ions in and out of bacterial cells, phospholipid (PL) membranes regulate the spatial and temporal position and function of membrane proteins that play an essential role in a variety of cellular functions. Based on the very large number of membrane-associated proteins encoded in genomes, an understanding of the role of PLs may be central to understanding bacterial cell biology. This area of microbiology has received considerable attention over the past two decades, and the local enrichment of anionic PLs has emerged as a candidate mechanism for biomolecular organization in bacterial cells. In this review, we summarize the current understanding of anionic PLs in bacteria, including their biosynthesis, subcellular localization, and physiological relevance, discuss evidence and mechanisms for enriching anionic PLs in membranes, and conclude with an assessment of future directions for this area of bacterial biochemistry, biophysics, and cell biology.
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Affiliation(s)
- Ti-Yu Lin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Douglas B Weibel
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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29
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Chavarha M, Loney RW, Rananavare SB, Hall SB. Hydrophobic surfactant proteins strongly induce negative curvature. Biophys J 2016; 109:95-105. [PMID: 26153706 DOI: 10.1016/j.bpj.2015.05.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 04/23/2015] [Accepted: 05/28/2015] [Indexed: 01/31/2023] Open
Abstract
The hydrophobic surfactant proteins SP-B and SP-C greatly accelerate the adsorption of vesicles containing the surfactant lipids to form a film that lowers the surface tension of the air/water interface in the lungs. Pulmonary surfactant enters the interface by a process analogous to the fusion of two vesicles. As with fusion, several factors affect adsorption according to how they alter the curvature of lipid leaflets, suggesting that adsorption proceeds via a rate-limiting structure with negative curvature, in which the hydrophilic face of the phospholipid leaflets is concave. In the studies reported here, we tested whether the surfactant proteins might promote adsorption by inducing lipids to adopt a more negative curvature, closer to the configuration of the hypothetical intermediate. Our experiments used x-ray diffraction to determine how the proteins in their physiological ratio affect the radius of cylindrical monolayers in the negatively curved, inverse hexagonal phase. With binary mixtures of dioleoylphosphatidylethanolamine (DOPE) and dioleoylphosphatidylcholine (DOPC), the proteins produced a dose-related effect on curvature that depended on the phospholipid composition. With DOPE alone, the proteins produced no change. With an increasing mol fraction of DOPC, the response to the proteins increased, reaching a maximum 50% reduction in cylindrical radius at 5% (w/w) protein. This change represented a doubling of curvature at the outer cylindrical surface. The change in spontaneous curvature, defined at approximately the level of the glycerol group, would be greater. Analysis of the results in terms of a Langmuir model for binding to a surface suggests that the effect of the lipids is consistent with a change in the maximum binding capacity. Our findings show that surfactant proteins can promote negative curvature, and support the possibility that they facilitate adsorption by that mechanism.
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Affiliation(s)
- Mariya Chavarha
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon; Department of Medicine, Oregon Health & Science University, Portland, Oregon; Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon
| | - Ryan W Loney
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon; Department of Medicine, Oregon Health & Science University, Portland, Oregon; Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon
| | | | - Stephen B Hall
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon; Department of Medicine, Oregon Health & Science University, Portland, Oregon; Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, Oregon.
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30
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Bitto D, Halldorsson S, Caputo A, Huiskonen JT. Low pH and Anionic Lipid-dependent Fusion of Uukuniemi Phlebovirus to Liposomes. J Biol Chem 2016; 291:6412-22. [PMID: 26811337 PMCID: PMC4813561 DOI: 10.1074/jbc.m115.691113] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Indexed: 12/14/2022] Open
Abstract
Many phleboviruses (family Bunyaviridae) are emerging as medically important viruses. These viruses enter target cells by endocytosis and low pH-dependent membrane fusion in late endosomes. However, the necessary and sufficient factors for fusion have not been fully characterized. We have studied the minimal fusion requirements of a prototypic phlebovirus, Uukuniemi virus, in an in vitro virus-liposome assay. We show that efficient lipid mixing between viral and liposome membranes requires close to physiological temperatures and phospholipids with negatively charged headgroups, such as the late endosomal phospholipid bis(monoacylglycero)phosphate. We further demonstrate that bis(monoacylglycero)phosphate increases Uukuniemi virus fusion beyond the lipid mixing stage. By using electron cryotomography of viral particles in the presence or absence of liposomes, we observed that the conformation of phlebovirus glycoprotein capsomers changes from the native conformation toward a more elongated conformation at a fusion permissive pH. Our results suggest a rationale for phlebovirus entry in late endosomes.
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Affiliation(s)
- David Bitto
- From the Division of Structural Biology, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Steinar Halldorsson
- From the Division of Structural Biology, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Alessandro Caputo
- From the Division of Structural Biology, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Juha T Huiskonen
- From the Division of Structural Biology, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, United Kingdom
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31
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Chen YF, Tsang KY, Chang WF, Fan ZA. Differential dependencies on [Ca2+] and temperature of the monolayer spontaneous curvatures of DOPE, DOPA and cardiolipin: effects of modulating the strength of the inter-headgroup repulsion. SOFT MATTER 2015; 11:4041-4053. [PMID: 25907686 DOI: 10.1039/c5sm00577a] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Biomembranes assume nonlamellar structures in many cellular events, with the tendency of forming a nonlamellar structure quantified by the monolayer spontaneous curvature, C(0), and with many of these events involving the acts of Ca(2+). Despite this biologically important intimacy, how C(0) is affected by [Ca(2+)] is unknown. In this study, we use the X-ray diffraction technique and the reconstruction of electron density profiles to measure the C(0)s of a zwitterionic phospholipid, DOPE, and two anionic phospholipids, DOPA and 18 : 1 (9Z) cardiolipin, at temperatures from 20 °C to 40 °C and [Ca(2+)]s from 0 mM to 100 mM; these phospholipids are chosen to examine the contributions of the electric charge density per molecule. While showing a strong dependence on temperature, C(0,DOPE) is nearly independent of [Ca(2+)]. In contrast, C(0,DOPA) and C(0),cardiolipin are almost unresponsive to the temperature change but affected by the [Ca(2+)] variation; and C(0,DOPA) varies with [Ca(2+)] ∼1.5 times more strongly than C(0,cardiolipin), with the phase preferences of DOPA and cardiolipin shifting to the H(II) phase and remaining on the Lα phase, respectively, at [Ca(2+)] = 100 mM. From these observations, we reveal the effects of modulating the strength of the inter-headgroup repulsion and discuss the mechanisms underlying the phase behaviour and cellular functions of the investigated phospholipids. Most importantly, this study recognizes that the headgroup charge density is dominant in dictating the phase behaviour of the anionic phospholipids, and that the unique molecular characteristics of cardiolipin are critically needed both for maintaining the structural integrity of cardiolipin-rich biomembranes and for fulfilling the biological roles of the phospholipid.
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Affiliation(s)
- Y-F Chen
- Department of Chemical and Materials Engineering, National Central University, Taoyuan 32001, Taiwan.
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32
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Tran N, Mulet X, Hawley AM, Hinton TM, Mudie ST, Muir BW, Giakoumatos EC, Waddington LJ, Kirby NM, Drummond CJ. Nanostructure and cytotoxicity of self-assembled monoolein–capric acid lyotropic liquid crystalline nanoparticles. RSC Adv 2015. [DOI: 10.1039/c5ra02604k] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Monoolein–capric acid combinations form into particles with internal nanostructures, including inverse hexagonal and bicontinuous cubic mesophases, with differing cytotoxicity.
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Affiliation(s)
- Nhiem Tran
- CSIRO Manufacturing Flagship
- Clayton
- 3168 Australia
- SAXS/WAXS beamline
- Australian Synchrotron
| | - Xavier Mulet
- CSIRO Manufacturing Flagship
- Clayton
- 3168 Australia
| | | | - Tracey M. Hinton
- CSIRO Animal, Food and Health Sciences
- Australian Animal Health Laboratory
- East Geelong
- 3219 Australia
| | | | | | | | | | - Nigel M. Kirby
- SAXS/WAXS beamline
- Australian Synchrotron
- Clayton
- 3168 Australia
| | - Calum J. Drummond
- CSIRO Manufacturing Flagship
- Clayton
- 3168 Australia
- School of Applied Sciences
- College of Science, Engineering and Health
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33
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Sychev SV, Balandin SV, Panteleev PV, Barsukov LI, Ovchinnikova TV. Lipid-dependent pore formation by antimicrobial peptides arenicin-2 and melittin demonstrated by their proton transfer activity. J Pept Sci 2014; 21:71-6. [DOI: 10.1002/psc.2724] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 12/23/2022]
Affiliation(s)
- Sergei V. Sychev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Russian Academy of Sciences; Miklukho-Maklaya St, 16/10 117997 Moscow Russia
| | - Sergey V. Balandin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Russian Academy of Sciences; Miklukho-Maklaya St, 16/10 117997 Moscow Russia
| | - Pavel V. Panteleev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Russian Academy of Sciences; Miklukho-Maklaya St, 16/10 117997 Moscow Russia
| | - Leonid I. Barsukov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Russian Academy of Sciences; Miklukho-Maklaya St, 16/10 117997 Moscow Russia
| | - Tatiana V. Ovchinnikova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Russian Academy of Sciences; Miklukho-Maklaya St, 16/10 117997 Moscow Russia
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34
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Abstract
Cardiolipin (CL) is an anionic phospholipid with a characteristically large curvature and is of growing interest for two primary reasons: (i) it binds to and regulates many peripheral membrane proteins in bacteria and mitochondria, and (ii) it is distributed asymmetrically in rod-shaped cells and is concentrated at the poles and division septum. Despite the growing number of studies of CL, its function in bacteria remains unknown. 10-N-Nonyl acridine orange (NAO) is widely used to image CL in bacteria and mitochondria, as its interaction with CL is reported to produce a characteristic red-shifted fluorescence emission. Using a suite of biophysical techniques, we quantitatively studied the interaction of NAO with anionic phospholipids under physiologically relevant conditions. We found that NAO is promiscuous in its binding and has photophysical properties that are largely insensitive to the structure of diverse anionic phospholipids to which it binds. Being unable to rely solely on NAO to characterize the localization of CL in Escherichia coli cells, we instead used quantitative fluorescence microscopy, mass spectrometry, and mutants deficient in specific classes of anionic phospholipids. We found CL and phosphatidylglycerol (PG) concentrated in the polar regions of E. coli cell membranes; depletion of CL by genetic approaches increased the concentration of PG at the poles. Previous studies suggested that some CL-binding proteins also have a high affinity for PG and display a pattern of cellular localization that is not influenced by depletion of CL. Framed within the context of these previous experiments, our results suggest that PG may play an essential role in bacterial physiology by maintaining the anionic character of polar membranes.
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35
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Preuß S, Scheiermann J, Stadelmann S, Omam FD, Winoto-Morbach S, Lex D, von Bismarck P, Adam-Klages S, Knerlich-Lukoschus F, Wesch D, Held-Feindt J, Uhlig S, Schütze S, Krause MF. 18:1/18:1-Dioleoyl-phosphatidylglycerol prevents alveolar epithelial apoptosis and profibrotic stimulus in a neonatal piglet model of acute respiratory distress syndrome. Pulm Pharmacol Ther 2014; 28:25-34. [DOI: 10.1016/j.pupt.2013.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/16/2013] [Accepted: 10/05/2013] [Indexed: 10/26/2022]
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36
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Gillams RJ, Nylander T, Plivelic TS, Dymond MK, Attard GS. Formation of inverse topology lyotropic phases in dioleoylphosphatidylcholine/oleic acid and dioleoylphosphatidylethanolamine/oleic acid binary mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:3337-3344. [PMID: 24605989 DOI: 10.1021/la404275u] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The addition of saturated fatty acids (FA) to phosphatidylcholine lipids (PC) that have saturated acyl chains has been shown to promote the formation of lyotropic liquid-crystalline phases with negative mean curvature. PC/FA mixtures may exhibit inverse bicontinuous cubic phases (Im3m, Pn3m) or inverse topology hexagonal phases (HII), depending on the length of the acyl chains/fatty acid. Here we report a detailed study of the phase behavior of binary mixtures of dioleoylphosphatidylcholine (DOPC)/oleic acid (OA) and dioleoylphosphatidylethanolamine (DOPE)/oleic acid at limiting hydration, constructed using small-angle X-ray diffraction (SAXD) data. The phase diagrams of both systems show a succession of phases with increasing negative mean curvature with increasing OA content. At high OA concentrations, we have observed the occurrence of an inverse micellar Fd3m phase in both systems. Hitherto, this phase had not been reported for phosphatidylethanolamine/fatty acid mixtures, and as such it highlights an additional route through which fatty acids may increase the propensity of bilayer lipid membranes to curve. We also propose a method that uses the temperature dependence of the lattice parameters of the HII phases to estimate the spontaneous radii of curvature (R0) of the binary mixtures and of the component lipids. Using this method, we calculated the R0 values of the complexes comprising one phospholipid molecule and two fatty acid molecules, which have been postulated to drive the formation of inverse phases in PL/FA mixtures. These are -1.8 nm (±0.4 nm) for DOPC(OA)2 and -1.1 nm (±0.1 nm) for DOPE(OA)2. R0 values estimated in this way allow the quantification of the contribution that different lipid species make to membrane curvature elastic properties and hence of their effect on the function of membrane-bound proteins.
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Affiliation(s)
- Richard J Gillams
- Faculty of Natural & Environmental Sciences, University of Southampton , Southampton SO17 1BJ, U.K
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37
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Kollmitzer B, Heftberger P, Rappolt M, Pabst G. Monolayer spontaneous curvature of raft-forming membrane lipids. SOFT MATTER 2013; 9:10877-10884. [PMID: 24672578 PMCID: PMC3963256 DOI: 10.1039/c3sm51829a] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Monolayer spontaneous curvatures for cholesterol, DOPE, POPE, DOPC, DPPC, DSPC, POPC, SOPC, and egg sphingomyelin were obtained using small-angle X-ray scattering (SAXS) on inverted hexagonal phases (HII). Spontaneous curvatures of bilayer forming lipids were estimated by adding controlled amounts to a HII forming template following previously established protocols. Spontaneous curvatures of both phosphatidylethanolamines and cholesterol were found to be at least a factor of two more negative than those of phosphatidylcholines, whose J0 values are closer to zero. Interestingly, a significant positive J0 value was retrieved for DPPC. We further determined the temperature dependence of the spontaneous curvatures J0(T) in the range from 15 to 55 °C, resulting in a quite narrow distribution of -1 to -3 × 10-3 (nm °C)-1 for most investigated lipids. The data allowed us to estimate the monolayer spontaneous curvatures of ternary lipid mixtures showing liquid ordered/liquid disordered phase coexistence. We report spontaneous curvature phase diagrams for DSPC/DOPC/Chol, DPPC/DOPC/Chol and SM/POPC/Chol and discuss effects on protein insertion and line tension.
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Affiliation(s)
- Benjamin Kollmitzer
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Austria. ; ; Tel: +43 316 4120-342
| | - Peter Heftberger
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Austria. ; ; Tel: +43 316 4120-342
| | - Michael Rappolt
- Institute of Inorganic Chemistry, Graz University of Technology, Austria ; School of Food Science and Nutrition, University of Leeds, UK
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Austria. ; ; Tel: +43 316 4120-342
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38
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Insertion of apoLp-III into a lipid monolayer is more favorable for saturated, more ordered, acyl-chains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:482-92. [PMID: 24099741 DOI: 10.1016/j.bbamem.2013.09.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 09/20/2013] [Accepted: 09/25/2013] [Indexed: 11/22/2022]
Abstract
Neutral lipid transport in mammals is complicated involving many types of apolipoprotein. The exchangeable apolipoproteins mediate the transfer of hydrophobic lipids between tissues and particles, and bind to cell surface receptors. Amphipathic α-helices form a common structural motif that facilitates their lipid binding and exchangeability. ApoLp-III, the only exchangeable apolipoprotein found in insects, is a model amphipathic α-helix bundle protein and its three dimensional structure and function mimics that of the mammalian proteins apoE and apoAI. Even the intracellular exchangeable lipid droplet protein TIP47/perilipin 3 contains an α-helix bundle domain with high structural similarity to that of apoE and apoLp-III. Here, we investigated the interaction of apoLp-III from Locusta migratoria with lipid monolayers. Consistent with earlier work we find that insertion of apoLp-III into fluid lipid monolayers is highest for diacylglycerol. We observe a preference for saturated and more highly ordered lipids, suggesting a new mode of interaction for amphipathic α-helix bundles. X-ray reflectivity shows that apoLp-III unfolds at a hydrophobic interface and flexible loops connecting the amphipathic α-helices stay in solution. X-ray diffraction indicates that apoLp-III insertion into diacylglycerol monolayers induces additional ordering of saturated acyl-chains. These results thus shed important new insight into the protein-lipid interactions of a model exchangeable apolipoprotein with significant implications for its mammalian counterparts.
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39
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Chavarha M, Loney RW, Rananavare SB, Hall SB. An anionic phospholipid enables the hydrophobic surfactant proteins to alter spontaneous curvature. Biophys J 2013; 104:594-603. [PMID: 23442910 DOI: 10.1016/j.bpj.2012.12.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 12/20/2012] [Accepted: 12/26/2012] [Indexed: 10/27/2022] Open
Abstract
The hydrophobic surfactant proteins, SP-B and SP-C, greatly accelerate the adsorption of the surfactant lipids to an air/water interface. Previous studies of factors that affect curvature suggest that vesicles may adsorb via a rate-limiting structure with prominent negative curvature, in which the hydrophilic face of the lipid leaflets is concave. To determine if SP-B and SP-C might promote adsorption by inducing negative curvature, we used small-angle x-ray scattering to test whether the physiological mixture of the two proteins affects the radius of cylindrical monolayers in the inverse hexagonal phase. With dioleoyl phosphatidylethanolamine alone, the proteins had no effect on the hexagonal lattice constant, suggesting that the proteins fail to insert into the cylindrical monolayers. The surfactant lipids also contain ∼10% anionic phospholipids, which might allow incorporation of the cationic proteins. With 10% of the anionic dioleoyl phosphatidylglycerol added to dioleoyl phosphatidylethanolamine, the proteins induced a dose-related decrease in the hexagonal lattice constant. At 30°C, the reduction reached a maximum of 8% relative to the lipids alone at ∼1% (w/w) protein. Variation of NaCl concentration tested whether the effect of the protein represented a strictly electrostatic effect that screening by electrolyte would eliminate. With concentrations up to 3 M NaCl, the dose-related change in the hexagonal lattice constant decreased but persisted. Measurements at different hydrations determined the location of the pivotal plane and proved that the change in the lattice constant produced by the proteins resulted from a shift in spontaneous curvature. These results provide the most direct evidence yet that the surfactant proteins can induce negative curvature in lipid leaflets. This finding supports the model in which the proteins promote adsorption by facilitating the formation of a negatively curved, rate-limiting structure.
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Affiliation(s)
- Mariya Chavarha
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon, USA
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Mondal S, Khelashvili G, Shi L, Weinstein H. The cost of living in the membrane: a case study of hydrophobic mismatch for the multi-segment protein LeuT. Chem Phys Lipids 2013; 169:27-38. [PMID: 23376428 PMCID: PMC3631462 DOI: 10.1016/j.chemphyslip.2013.01.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 01/15/2013] [Accepted: 01/15/2013] [Indexed: 12/27/2022]
Abstract
Many observations of the role of the membrane in the function and organization of transmembrane (TM) proteins have been explained in terms of hydrophobic mismatch between the membrane and the inserted protein. For a quantitative investigation of this mechanism in the lipid-protein interactions of functionally relevant conformations adopted by a multi-TM segment protein, the bacterial leucine transporter (LeuT), we employed a novel method, Continuum-Molecular Dynamics (CTMD), that quantifies the energetics of hydrophobic mismatch by combining the elastic continuum theory of membrane deformations with an atomistic level description of the radially asymmetric membrane-protein interface from MD simulations. LeuT has been serving as a model for structure-function studies of the mammalian neurotransmitter:sodium symporters (NSSs), such as the dopamine and serotonin transporters, which are the subject of intense research in the field of neurotransmission. The membrane models in which LeuT was embedded for these studies were composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid, or 3:1 mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) lipids. The results show that deformation of the host membrane alone is not sufficient to alleviate the hydrophobic mismatch at specific residues of LeuT. The calculations reveal significant membrane thinning and water penetration due to the specific local polar environment produced by the charged K288 of TM7 in LeuT, that is membrane-facing deep inside the hydrophobic milieu of the membrane. This significant perturbation is shown to result in unfavorable polar-hydrophobic interactions at neighboring hydrophobic residues in TM1a and TM7. We show that all the effects attributed to the K288 residue (membrane thinning, water penetration, and the unfavorable polar-hydrophobic interactions at TM1a and TM7), are abolished in calculations with the K288A mutant. The involvement of hydrophobic mismatch is somewhat different in the functionally distinct conformations (outward-open, occluded, inward-open) of LeuT, and the differences are shown to connect to structural elements (e.g., TM1a) known to play key roles in transport. This finding suggests a mechanistic hypothesis for the enhanced transport activity observed for the K288A mutant, suggesting that the unfavorable hydrophobic-hydrophilic interactions hinder the motion of TM1a in the functionally relevant conformational transition to the inward-open state. Various extents of such unfavorable interactions, involving exposure to the lipid environment of adjacent hydrophobic and polar residues, are common in multi-segment transmembrane proteins, and must be considered to affect functionally relevant conformational transitions.
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Affiliation(s)
- Sayan Mondal
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, New York, NY 10065
| | - George Khelashvili
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, New York, NY 10065
| | - Lei Shi
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, New York, NY 10065
- The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medical College, Cornell University, New York, NY 10065
| | - Harel Weinstein
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, New York, NY 10065
- The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medical College, Cornell University, New York, NY 10065
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Coupling Membrane Elasticity and Structure to Protein Function. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-411515-6.00004-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Yaghmur A, Rappolt M. The Micellar Cubic Fd3m Phase. ADVANCES IN PLANAR LIPID BILAYERS AND LIPOSOMES 2013. [DOI: 10.1016/b978-0-12-411515-6.00005-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Boulgaropoulos B, Rappolt M, Sartori B, Amenitsch H, Pabst G. Lipid sorting by ceramide and the consequences for membrane proteins. Biophys J 2012; 102:2031-8. [PMID: 22824266 DOI: 10.1016/j.bpj.2012.03.059] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/08/2012] [Accepted: 03/23/2012] [Indexed: 01/09/2023] Open
Abstract
We mimicked the effect of sphingomyelinase activity on lipid mixtures of palmitoyl-oleoyl-phosphatidylcholine, sphingomyelin, ceramide, and 10 mol % cholesterol. Using x-ray diffraction experiments in combination with osmotic stress we found, in agreement with previous studies, that ceramide induces a coexistence of L(α) and L(β) domains. A detailed structural analysis of the coexisting domains demonstrated an increase of lipid packing density and membrane thickness in the L(α) domains upon increasing overall ceramide levels. This provides evidence for a ceramide-driven accumulation of cholesterol in the L(α) domains, in support of previous reports. We further determined the bending rigidities of the coexisting domains and found that the accumulation of cholesterol in the L(α) domains stabilizes their bending rigidity, which experiences a dramatic drop in the absence of cholesterol. Deriving experimental estimates for the spontaneous curvature and Gaussian modulus of curvature, we show, using a simple geometric model for ion channels, that in this way changes in the conformational equilibrium of membrane proteins can be kept small.
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Affiliation(s)
- Beate Boulgaropoulos
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Graz, Austria
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Strandberg E, Tiltak D, Ehni S, Wadhwani P, Ulrich AS. Lipid shape is a key factor for membrane interactions of amphipathic helical peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1764-76. [DOI: 10.1016/j.bbamem.2012.02.027] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 02/22/2012] [Accepted: 02/27/2012] [Indexed: 02/07/2023]
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Use of X-ray scattering to aid the design and delivery of membrane-active drugs. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:915-29. [DOI: 10.1007/s00249-012-0821-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 04/30/2012] [Accepted: 05/05/2012] [Indexed: 10/28/2022]
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Yang ST, Zaitseva E, Chernomordik LV, Melikov K. Cell-penetrating peptide induces leaky fusion of liposomes containing late endosome-specific anionic lipid. Biophys J 2011; 99:2525-33. [PMID: 20959093 DOI: 10.1016/j.bpj.2010.08.029] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 07/22/2010] [Accepted: 08/02/2010] [Indexed: 01/14/2023] Open
Abstract
Cationic cell-penetrating peptides (CPPs) are a promising vehicle for the delivery of macromolecular drugs. Although many studies have indicated that CPPs enter cells by endocytosis, the mechanisms by which they cross endosomal membranes remain elusive. On the basis of experiments with liposomes, we propose that CPP escape into the cytosol is based on leaky fusion (i.e., fusion associated with the permeabilization of membranes) of the bis(monoacylglycero)phosphate (BMP)-enriched membranes of late endosomes. In our experiments, prototypic CPP HIV-1 TAT peptide did not interact with liposomes mimicking the outer leaflet of the plasma membrane, but it did induce lipid mixing and membrane leakage as it translocated into liposomes mimicking the lipid composition of late endosome. Both membrane leakage and lipid mixing depended on the BMP content and were promoted at acidic pH, which is characteristic of late endosomes. Substitution of BMP with its structural isomer, phosphatidylglycerol (PG), significantly reduced both leakage of the aqueous probe from liposomes and lipid mixing between liposomes. Although affinity of binding to TAT was similar for BMP and PG, BMP exhibited a higher tendency to support the inverted hexagonal phase than PG. Finally, membrane leakage and peptide translocation were both inhibited by inhibitors of lipid mixing, further substantiating the hypothesis that cationic peptides cross BMP-enriched membranes by inducing leaky fusion between them.
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Affiliation(s)
- Sung-Tae Yang
- Section on Membrane Biology, Laboratory of Cellular and Molecular Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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Kulkarni CV, Wachter W, Iglesias-Salto G, Engelskirchen S, Ahualli S. Monoolein: a magic lipid? Phys Chem Chem Phys 2011; 13:3004-21. [DOI: 10.1039/c0cp01539c] [Citation(s) in RCA: 295] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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48
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daCosta CJB, Medaglia SA, Lavigne N, Wang S, Carswell CL, Baenziger JE. Anionic lipids allosterically modulate multiple nicotinic acetylcholine receptor conformational equilibria. J Biol Chem 2009; 284:33841-9. [PMID: 19815550 DOI: 10.1074/jbc.m109.048280] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Anionic lipids influence the ability of the nicotinic acetylcholine receptor to gate open in response to neurotransmitter binding, but the underlying mechanisms are poorly understood. We show here that anionic lipids with relatively small headgroups, and thus the greatest ability to influence lipid packing/bilayer physical properties, are the most effective at stabilizing an agonist-activatable receptor. The differing abilities of anionic lipids to stabilize an activatable receptor stem from differing abilities to preferentially favor resting over both uncoupled and desensitized conformations. Anionic lipids thus modulate multiple acetylcholine receptor conformational equilibria. Our data suggest that both lipids and membrane physical properties act as classic allosteric modulators influencing function by interacting with and thus preferentially stabilizing different native acetylcholine receptor conformational states.
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Affiliation(s)
- Corrie J B daCosta
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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Wikström M, Kelly AA, Georgiev A, Eriksson HM, Klement MR, Bogdanov M, Dowhan W, Wieslander A. Lipid-engineered Escherichia coli membranes reveal critical lipid headgroup size for protein function. J Biol Chem 2009; 284:954-65. [PMID: 18981182 PMCID: PMC2613627 DOI: 10.1074/jbc.m804482200] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 10/23/2008] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli membranes have a substantial bilayer curvature stress due to a large fraction of the nonbilayer-prone lipid phosphatidylethanolamine, and a mutant (AD93) lacking this lipid is severely crippled in several membrane-associated processes. Introduction of four lipid glycosyltransferases from Acholeplasma laidlawii and Arabidopsis thaliana, synthesizing large amounts of two nonbilayer-prone, and two bilayer-forming gluco- and galacto-lipids, (i) restored the curvature stress with the two nonbilayer lipids, and (ii) diluted the high negative lipid surface charge in all AD93 bilayers. Surprisingly, the bilayer-forming diglucosyl-diacylglycerol was almost as good in improving AD93 membrane processes as the two nonbilayer-prone glucosyl-diacylglycerol and galactosyl-diacylglycerol lipids, strongly suggesting that lipid surface charge dilution by these neutral lipids is very important for E. coli. Increased acyl chain length and unsaturation, plus cardiolipin (nonbilayer-prone) content, were probably also beneficial in the modified strains. However, despite a correct transmembrane topology for the transporter LacY in the diglucosyl-diacylglycerol clone, active transport failed in the absence of a nonbilayer-prone glycolipid. The corresponding digalactosyl-diacylglycerol bilayer lipid did not restore AD93 membrane processes, despite analogous acyl chain and cardiolipin contents. Chain ordering, probed by bis-pyrene lipids, was substantially lower in the digalactosyl-diacylglycerol strain lipids due to its extended headgroup. Hence, a low surface charge density of anionic lipids is important in E. coli membranes, but is inefficient if the headgroup of the diluting lipid is too large. This strongly indicates that a certain magnitude of the curvature stress is crucial for the bilayer in vivo.
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Affiliation(s)
- Malin Wikström
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
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