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da Cunha AR, Duarte EL, Vignoli Muniz GS, Coutinho K, Lamy MT. New insights into the interaction of emodin with lipid membranes. Biophys Chem 2024; 309:107233. [PMID: 38579435 DOI: 10.1016/j.bpc.2024.107233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/26/2024] [Accepted: 04/01/2024] [Indexed: 04/07/2024]
Abstract
Emodin is a natural anthraquinone derivative found in nature, widely known as an herbal medicine. Here, the partition, location, and interaction of emodin with lipid membranes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) are experimentally investigated with different techniques. Our studies have considered the neutral form of emodin (EMH) and its anionic/deprotonated form (EM-), and their interaction with a more and less packed lipid membrane, DMPC at the gel and fluid phases, respectively. Though DSC results indicate that the two species, EMH and EM-, similarly disrupt the packing of DMPC bilayers, spin labels clearly show that EMH causes a stronger bilayer disruption, both in gel and fluid DMPC. Fluorescence spectroscopy shows that both EMH and EM- have a high affinity for DMPC: the binding of EM- to both gel and fluid DMPC bilayers was found to be quite similar, and similar to that of EMH to gel DMPC, Kp = (1.4 ± 0.3)x103. However, EMH was found to bind twice more strongly to fluid DMPC bilayers, Kp = (3.2 ± 0.3)x103. Spin labels and optical absorption spectroscopy indicate that emodin is located close to the lipid bilayer surface, and suggest that EM- is closer to the lipid/water interface than EMH, as expected. The present studies present a relevant contribution to the current understanding of the effect the two species of emodin, EMH and EM-, present on different microregions of an organism, as local pH values can vary significantly, can cause in a neutral lipid membrane, either more or less packed, liked gel and fluid DMPC, respectively, and could be extended to lipid domains of biological membranes.
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Affiliation(s)
- Antonio R da Cunha
- Universidade Federal do Maranhão, UFMA, Campus Balsas, 65800-000, Maranhão, Brazil; Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil.
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil
| | - Gabriel S Vignoli Muniz
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil; Instituto de Química, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília 70910-900, Brazil
| | - Kaline Coutinho
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil
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Niedziałkowski P, Jurczak P, Orlikowska M, Wcisło A, Ryl J, Ossowski T, Czaplewska P. Phospholipid-functionalized gold electrode for cellular membrane interface studies - interactions between DMPC bilayer and human cystatin C. Biochim Biophys Acta Biomembr 2024; 1866:184266. [PMID: 38151198 DOI: 10.1016/j.bbamem.2023.184266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 12/14/2023] [Accepted: 12/20/2023] [Indexed: 12/29/2023]
Abstract
This work describes the electrochemical studies on the interactions between V57G mutant of human cystatin C (hCC V57G) and membrane bilayer immobilized on the surface of a gold electrode. The electrode was modified with 6-mercaptohexan-1-ol (MCH) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). DMPC was used as a membrane mimetic for monitoring electrochemical changes resulting from the interactions between the functionalized electrode surface and human cystatin C. The interactions between the modified electrode and hCC V57G were investigated by cyclic voltammetry and electrochemical impedance spectroscopy in a phosphate buffered saline (PBS) containing Fe(CN)63-/4- as a redox probe. The electrochemical measurements confirm that fabricated electrode is sensitive to hCC V57G at the concentration of 1 × 10-14 M. The incubation studies carried out at higher concentrations resulted in insignificant changes observed in cyclic voltammetry and electrochemical impedance spectroscopy measurements. The calculated values of surface coverage θR confirm that the electrode is equally covered at higher concentrations of hCC V57G. Measurements of wettability and surface free energy made it possible to determine the influence of individual structural elements of the modified gold electrode on its properties, and thus allowed to understand the nature of the interactions. Contact angle values confirmed the results obtained during electrochemical measurements, indicating the sensitivity of the electrode towards hCC V57G at the concentration of 1 × 10-14 M. In addition, the XPS spectra confirmed the successful anchoring of hCC V57G to the DMPC-functionalized surface.
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Affiliation(s)
- Paweł Niedziałkowski
- Department of Analytical Chemistry, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, Gdańsk 80-308, Poland.
| | - Przemysław Jurczak
- Department of Biomedical Chemistry, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, Gdańsk 80-308, Poland; Specialist Laboratories, Intercollegiate Faculty of Biotechnology UG&MUG, Abrahama 58, Gdańsk 80-307, Poland.
| | - Marta Orlikowska
- Department of Biomedical Chemistry, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, Gdańsk 80-308, Poland
| | - Anna Wcisło
- Department of Analytical Chemistry, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, Gdańsk 80-308, Poland
| | - Jacek Ryl
- Division of Electrochemistry and Surface Physical Chemistry, Institute of Nanotechnology and Materials Engineering and Advanced Materials Center, Gdańsk University of Technology, Narutowicza 11/12, Gdańsk 80-233, Poland
| | - Tadeusz Ossowski
- Department of Analytical Chemistry, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, Gdańsk 80-308, Poland
| | - Paulina Czaplewska
- Specialist Laboratories, Intercollegiate Faculty of Biotechnology UG&MUG, Abrahama 58, Gdańsk 80-307, Poland
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Bowers SR, Lockhart C, Klimov DK. Binding and dimerization of PGLa peptides in anionic lipid bilayer studied by replica exchange molecular dynamics. Sci Rep 2024; 14:4972. [PMID: 38424117 PMCID: PMC10904749 DOI: 10.1038/s41598-024-55270-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/21/2024] [Indexed: 03/02/2024] Open
Abstract
The 21-residue PGLa peptide is well known for antimicrobial activity attributed to its ability to compromize bacterial membranes. Using all-atom explicit solvent replica exchange molecular dynamics with solute tempering, we studied PGLa binding to a model anionic DMPC/DMPG bilayer at the high peptide:lipid ratio that promotes PGLa dimerization (a two peptides per leaflet system). As a reference we used our previous simulations at the low peptide:lipid ratio (a one peptide per leaflet system). We found that the increase in the peptide:lipid ratio suppresses PGLa helical propensity, tilts the bound peptide toward the bilayer hydrophobic core, and forces it deeper into the bilayer. Surprisingly, at the high peptide:lipid ratio PGLa binding induces weaker bilayer thinning, but deeper water permeation. We explain these effects by the cross-correlations between lipid shells surrounding PGLa that leads to a much diminished efflux of DMPC lipids from the peptide proximity at the high peptide:lipid ratio. Consistent with the experimental data the propensity for PGLa dimerization was found to be weak resulting in coexistence of monomers and dimers with distinctive properties. PGLa dimers assemble via apolar criss-cross interface and become partially expelled from the bilayer residing at the bilayer-water boundary. We rationalize their properties by the dimer tendency to preserve favorable electrostatic interactions between lysine and phosphate lipid groups as well as to avoid electrostatic repulsion between lysines in the low dielectric environment of the bilayer core. PGLa homedimer interface is predicted to be distinct from that involved in PGLa-magainin heterodimers.
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Affiliation(s)
- Steven R Bowers
- School of Systems Biology, George Mason University, Manassas, VA, 20110, USA
| | | | - Dmitri K Klimov
- School of Systems Biology, George Mason University, Manassas, VA, 20110, USA.
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Georgiou K, Konstantinidi A, Hutterer J, Freudenberger K, Kolarov F, Lambrinidis G, Stylianakis I, Stampelou M, Gauglitz G, Kolocouris A. Accurate calculation of affinity changes to the close state of influenza A M2 transmembrane domain in response to subtle structural changes of adamantyl amines using free energy perturbation methods in different lipid bilayers. Biochim Biophys Acta Biomembr 2024; 1866:184258. [PMID: 37995846 DOI: 10.1016/j.bbamem.2023.184258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/18/2023] [Accepted: 11/15/2023] [Indexed: 11/25/2023]
Abstract
Experimental binding free energies of 27 adamantyl amines against the influenza M2(22-46) WT tetramer, in its closed form at pH 8, were measured by ITC in DPC micelles. The measured Kd's range is ~44 while the antiviral potencies (IC50) range is ~750 with a good correlation between binding free energies computed with Kd and IC50 values (r = 0.76). We explored with MD simulations (ff19sb, CHARMM36m) the binding profile of complexes with strong, moderate and weak binders embedded in DMPC, DPPC, POPC or a viral mimetic membrane and using different experimental starting structures of M2. To predict accurately differences in binding free energy in response to subtle changes in the structure of the ligands, we performed 18 alchemical perturbative single topology FEP/MD NPT simulations (OPLS2005) using the BAR estimator (Desmond software) and 20 dual topology calculations TI/MD NVT simulations (ff19sb) using the MBAR estimator (Amber software) for adamantyl amines in complex with M2(22-46) WT in DMPC, DPPC, POPC. We observed that both methods with all lipids show a very good correlation between the experimental and calculated relative binding free energies (r = 0.77-0.87, mue = 0.36-0.92 kcal mol-1) with the highest performance achieved with TI/MBAR and lowest performance with FEP/BAR in DMPC bilayers. When antiviral potencies are used instead of the Kd values for computing the experimental binding free energies we obtained also good performance with both FEP/BAR (r = 0.83, mue = 0.75 kcal mol-1) and TI/MBAR (r = 0.69, mue = 0.77 kcal mol-1).
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Affiliation(s)
- Kyriakos Georgiou
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Athina Konstantinidi
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Johanna Hutterer
- Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität, D-72076 Tübingen, Germany
| | - Kathrin Freudenberger
- Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität, D-72076 Tübingen, Germany
| | - Felix Kolarov
- Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität, D-72076 Tübingen, Germany; Roche, Penzberg, Bavaria, Germany
| | - George Lambrinidis
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Ioannis Stylianakis
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Margarita Stampelou
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Günter Gauglitz
- Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität, D-72076 Tübingen, Germany
| | - Antonios Kolocouris
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece.
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Reszczyńska E, Wiśniewska-Becker A, Duda M, Sęk A, Gruszecki WI, Hanaka A. The presence of free palmitic acid modulates the effects of lutein on structural and dynamic properties of lipid membranes. Arch Biochem Biophys 2024; 752:109883. [PMID: 38211638 DOI: 10.1016/j.abb.2024.109883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/15/2023] [Accepted: 01/08/2024] [Indexed: 01/13/2024]
Abstract
Free fatty acids, like palmitic acid (PA), and xanthophyll pigments, like lutein (LUT) are the natural membrane compounds in plants. To study the effect of PA on LUT and their organization, a model membrane of 1,2-dimyristoyl-sn-glycerol-3-phosphocholine (DMPC) enriched with 2 mol% PA and 1 mol% LUT was formed. Molecular mechanisms underlying the interaction between these two compounds were examined with application of molecular spectroscopy techniques, e.g., visible spectroscopy, electron paramagnetic resonance and Fourier transform infrared. We determined the monomeric/dimeric organization of LUT in the membrane. We proved that the presence of PA in the lipid phase facilitated and stabilized the formation of LUT structures in the membrane. Lutein with PA did not form strong molecular aggregates like H- and J-structures. We presented the simplified model membrane that could be a suitable representation of the physiological process of de-esterification of PA from LUT appearing in natural biomembranes in humans.
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Affiliation(s)
- Emilia Reszczyńska
- Department of Biochemistry and Molecular Biology, Medical University of Lublin, W. Chodźki 1 Street, 20-093, Lublin, Poland; Department of Plant Physiology and Biophysics, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 Street, 20-033, Lublin, Poland.
| | - Anna Wiśniewska-Becker
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7 Street, 30-387, Krakow, Poland
| | - Mariusz Duda
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7 Street, 30-387, Krakow, Poland
| | - Alicja Sęk
- Department of Biophysics, Faculty of Mathematics, Physics and Computer Science, Maria Curie-Skłodowska University, M. Curie-Skłodowska Square 1, 20-031, Lublin, Poland; The National Institute of Horticultural Research, Konstytucji 3 Maja 1/3 Street, 96-100, Skierniewice, Poland
| | - Wiesław I Gruszecki
- Department of Biophysics, Faculty of Mathematics, Physics and Computer Science, Maria Curie-Skłodowska University, M. Curie-Skłodowska Square 1, 20-031, Lublin, Poland
| | - Agnieszka Hanaka
- Department of Plant Physiology and Biophysics, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 Street, 20-033, Lublin, Poland
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Selvasingh JA, McDonald EF, Neufer PD, McKinney JR, Meiler J, Ledwitch KV. Dark nanodiscs for evaluating membrane protein thermostability by differential scanning fluorimetry. Biophys J 2024; 123:68-79. [PMID: 37978799 PMCID: PMC10808023 DOI: 10.1016/j.bpj.2023.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/27/2023] [Accepted: 11/16/2023] [Indexed: 11/19/2023] Open
Abstract
Measuring protein thermostability provides valuable information on the biophysical rules that govern the structure-energy relationships of proteins. However, such measurements remain a challenge for membrane proteins. Here, we introduce a new experimental system to evaluate membrane protein thermostability. This system leverages a recently developed nonfluorescent membrane scaffold protein to reconstitute proteins into nanodiscs and is coupled with a nano-format of differential scanning fluorimetry (nanoDSF). This approach offers a label-free and direct measurement of the intrinsic tryptophan fluorescence of the membrane protein as it unfolds in solution without signal interference from the "dark" nanodisc. In this work, we demonstrate the application of this method using the disulfide bond formation protein B (DsbB) as a test membrane protein. NanoDSF measurements of DsbB reconstituted in dark nanodiscs loaded with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dimyristoyl-sn-glycero-3-phosphorylglycerol (DMPG) lipids show a complex biphasic thermal unfolding pattern with a minor unfolding transition followed by a major transition. The inflection points of the thermal denaturation curve reveal two distinct unfolding midpoint melting temperatures (Tm) of 70.5°C and 77.5°C, consistent with a three-state unfolding model. Further, we show that the catalytically conserved disulfide bond between residues C41 and C130 drives the intermediate state of the unfolding pathway for DsbB in a DMPC and DMPG nanodisc. To extend the utility of this method, we evaluate and compare the thermostability of DsbB in different lipid environments. We introduce this method as a new tool that can be used to understand how compositionally and biophysically complex lipid environments drive membrane protein stability.
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Affiliation(s)
- Jazlyn A Selvasingh
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee
| | - Eli F McDonald
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee
| | - Preston D Neufer
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee
| | - Jacob R McKinney
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee; Institute of Drug Discovery, Faculty of Medicine, University of Leipzig, Leipzig, Germany.
| | - Kaitlyn V Ledwitch
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee.
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7
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Allen P, Smith AC, Benedicto V, Abdulhasan A, Narayanaswami V, Tapavicza E. Molecular dynamics simulation of apolipoprotein E3 lipid nanodiscs. Biochim Biophys Acta Biomembr 2024; 1866:184230. [PMID: 37704040 DOI: 10.1016/j.bbamem.2023.184230] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023]
Abstract
Nanodiscs are binary discoidal complexes of a phospholipid bilayer circumscribed by belt-like helical scaffold proteins. Using coarse-grained and all-atom molecular dynamics simulations, we explore the stability, size, and structure of nanodiscs formed between the N-terminal domain of apolipoprotein E3 (apoE3-NT) and variable number of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) molecules. We study both parallel and antiparallel double-belt configurations, consisting of four proteins per nanodisc. Our simulations predict nanodiscs containing between 240 and 420 DMPC molecules to be stable. The antiparallel configurations exhibit an average of 1.6 times more amino acid interactions between protein chains and 2 times more ionic contacts, compared to the parallel configuration. With one exception, DMPC order parameters are consistently larger in the antiparallel configuration than in the parallel one. In most cases, the root mean square deviation of the positions of the protein backbone atoms is smaller in the antiparallel configuration. We further report nanodisc size, thickness, radius of gyration, and solvent accessible surface area. Combining all investigated parameters, we hypothesize the antiparallel protein configuration leading to more stable and more rigid nanodiscs than the parallel one.
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Affiliation(s)
- Patrick Allen
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, 90840, CA, USA
| | - Adam C Smith
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, 90840, CA, USA
| | - Vernon Benedicto
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, 90840, CA, USA
| | - Abbas Abdulhasan
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, 90840, CA, USA
| | - Vasanthy Narayanaswami
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, 90840, CA, USA
| | - Enrico Tapavicza
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, 90840, CA, USA.
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Abbas A, Oswald E, Romer J, Lenzer A, Heiland M, Streb C, Kranz C, Pannwitz A. Initial Quenching Efficiency Determines Light-Driven H 2 Evolution of [Mo 3 S 13 ] 2- in Lipid Bilayers. Chemistry 2023; 29:e202302284. [PMID: 37699127 DOI: 10.1002/chem.202302284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/07/2023] [Accepted: 09/10/2023] [Indexed: 09/14/2023]
Abstract
Nature uses reactive components embedded in biological membranes to perform light-driven photosynthesis. Here, a model artificial photosynthetic system for light-driven hydrogen (H2 ) evolution is reported. The system is based on liposomes where amphiphilic ruthenium trisbipyridine based photosensitizer (RuC9 ) and the H2 evolution reaction (HER) catalyst [Mo3 S13 ]2- are embedded in biomimetic phospholipid membranes. When DMPC was used as the main lipid of these light-active liposomes, increased catalytic activity (TONCAT ~200) was observed compared to purely aqueous conditions. Although all tested lipid matrixes, including DMPC, DOPG, DPPC and DOPG liposomes provided similar liposomal structures according to TEM analysis, only DMPC yielded high H2 amounts. In situ scanning electrochemical microscopy (SECM) measurements using Pd microsensors revealed an induction period of around 26 minutes prior to H2 evolution, indicating an activation mechanism which might be induced by the fluid-gel phase transition of DMPC at room temperature. Stern-Volmer-type quenching studies revealed that electron transfer dynamics from the excited state photosensitizer are most efficient in the DMPC lipid environment giving insight for design of artificial photosynthetic systems using lipid bilayer membranes.
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Affiliation(s)
- Amir Abbas
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Eva Oswald
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Jan Romer
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Anja Lenzer
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Magdalena Heiland
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Carsten Streb
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Christine Kranz
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Andrea Pannwitz
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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9
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Xu J, Karra V, Large DE, Auguste DT, Hung FR. Understanding the Mechanical Properties of Ultradeformable Liposomes Using Molecular Dynamics Simulations. J Phys Chem B 2023; 127:9496-9512. [PMID: 37879075 PMCID: PMC10641833 DOI: 10.1021/acs.jpcb.3c04386] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/19/2023] [Accepted: 10/04/2023] [Indexed: 10/27/2023]
Abstract
Improving drug delivery efficiency to solid tumor sites is a central challenge in anticancer therapeutic research. Our previous experimental study (Guo et al., Nat. Commun. 2018, 9, 130) showed that soft, elastic liposomes had increased uptake and accumulation in cancer cells and tumors in vitro and in vivo respectively, relative to rigid particles. As a first step toward understanding how liposomes' molecular structure and composition modulates their elasticity, we performed all-atom and coarse-grained classical molecular dynamics (MD) simulations of lipid bilayers formed by mixing a long-tailed unsaturated phospholipid with a short-tailed saturated lipid with the same headgroup. The former types of phospholipids considered were 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dipalmitoleoyl-sn-glycero-3-phosphocholine (termed here DPMPC). The shorter saturated lipids examined were 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DHPC), 1,2-didecanoyl-sn-glycero-3-phosphocholine (DDPC), 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). Several lipid concentrations and surface tensions were considered. Our results show that DOPC or DPMPC systems having 25-35 mol % of the shortest lipids DHPC or DDPC are the least rigid, having area compressibility moduli KA that are ∼10% smaller than the values observed in pure DOPC or DPMPC bilayers. These results agree with experimental measurements of the stretching modulus and lysis tension in liposomes with the same compositions. These mixed systems also have lower areas per lipid and form more uneven x-y interfaces with water, the tails of both primary and secondary lipids are more disordered, and the terminal methyl groups in the tails of the long lipid DOPC or DPMPC wriggle more in the vertical direction, compared to pure DOPC or DPMPC bilayers or their mixtures with the longer saturated lipid DLPC or DMPC. These observations confirm our hypothesis that adding increasing concentrations of the short unsaturated lipid DHPC or DDPC to DOPC or DPMPC bilayers alters lipid packing and thus makes the resulting liposomes more elastic and less rigid. No formation of lipid nanodomains was noted in our simulations, and no clear trends were observed in the lateral diffusivities of the lipids as the concentration, type of secondary lipid, and surface tension were varied.
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Affiliation(s)
- Jiaming Xu
- Department
of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Vyshnavi Karra
- Department
of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Danielle E. Large
- Department
of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Debra T. Auguste
- Department
of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
- Department
of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Francisco R. Hung
- Department
of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
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10
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Schwörer F, Trapp M, Silvi L, Gutfreund P, Steitz R, Dahint R. Location of Polyelectrolytes in Swollen Lipid Oligobilayers. Langmuir 2023; 39:14958-14968. [PMID: 37815275 DOI: 10.1021/acs.langmuir.3c01792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Osteoarthritis is caused by degeneration of the cartilage, which covers the bone ends of the joints and is decorated with an oligolamellar phospholipid (PL) bilayer. The gap between the bone ends is filled with synovial fluid mainly containing hyaluronic acid (HA). HA and PLs are supposed to reduce friction and protect the cartilage from wear in joint movement. However, a detailed understanding of the molecular mechanisms of joint lubrication is still missing. Previously, we found that aqueous solutions of HA and poly(allylamine hydrochloride) (PAH), the latter serving as a polymeric analogue to HA, adsorb onto the headgroups of surface-bound 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) oligobilayers and significantly enhance their stability with respect to shear forces, typically occurring in joint movement. We now investigated the precise location of PAH chains across the lipid films in neutron reflectivity measurements, as bridging of the oligobilayers by polyelectrolytes (PEs) might be the cause for their improved mechanical stability. In a first set of experiments, we used hydrogenated PAH and chain-deuterated DMPC (DMPC-d54) to improve the contrast between the lipids and potentially intruding PAH. However, due to difficulties in distinguishing between incorporation of water and PAH, penetration into the lipid chain region could hardly be proven quantitatively. Therefore, we designed a more elaborate experiment based on mixed films of DMPC-d54 and hydrogenated DMPC, which is insensitive to water penetration into the films. Beside facilitating a detailed structural characterization of the oligolamellar system, this elaborate approach showed that PAH adsorbs to the DMPC heads and penetrates the lipid tail strata. No PAH was found in the lipid head strata, which excludes bridging of several lipid bilayers by the PE chains. The data are consistent with the assumption that PAH bridges are formed between the headgroups of two adjacent bilayers and contribute to the enhanced mechanical stability.
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Affiliation(s)
- Felicitas Schwörer
- Applied Physical Chemistry, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 253, Heidelberg 69120, Germany
| | - Marcus Trapp
- Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Luca Silvi
- Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | | | - Roland Steitz
- Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Reiner Dahint
- Applied Physical Chemistry, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 253, Heidelberg 69120, Germany
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11
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Aloi E, Tone CM, Barberi RC, Ciuchi F, Bartucci R. Effects of curcumin in the interaction with cardiolipin-containg lipid monolayers and bilayers. Biophys Chem 2023; 301:107082. [PMID: 37544082 DOI: 10.1016/j.bpc.2023.107082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 07/21/2023] [Accepted: 07/30/2023] [Indexed: 08/08/2023]
Abstract
Curcumin, a plant polyphenol extracted from the Chinese herb turmeric, has gained widespread attention in recent years because of its multifunctional properties as antioxidant, antinflammatory, antimicrobial, and anticancer agent. Effects of the molecule on mitochondrial membranes properties have also been evidenced. In this work, the interaction of curcumin with models of mitochondrial membranes composed of dimyristoylphosphatidylcholine (DMPC) or mixtures of DMPC and 4 mol% tetramyristoylcardiolipin (TMCL) has been investigated by using biophysical techniques. Spectrophotometry and fluorescence allowed to determine the association constant and the binding energy of curcumin with pure DMPC and mixed DMPC/TMCL aqueous bilayers. The molecular organization of pure DMPC and cardiolipin-containing Langmuir monolayers at the air-water interface were investigated and the morphology of the monolayers transferred into mica substrates were characterized through atomic force microscopy (AFM). It is found that curcumin associates at the polar/apolar interface of the lipid bilayers and the binding is favored in the presence of cardiolipin. At 2 mol%, curcumin is well miscible with lipid monolayers, particularly with mixed DMPC/TMCL ones, where compact terraces formation characterized by a reduction of the surface roughness is observed in the AFM topographic images. At 10 mol%, curcumin perturbs the stability of DMPC monolayers and morphologically are evident terraces surrounded by cur aggregates. In the presence of TMCL, very few curcumin aggregates and larger compact terraces are observed. The overall results indicate that cardiolipin augments the incorporation of curcumin in model membranes highlighting the mutual interplay cardiolipin-curcumin in mitochondrial membranes.
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Affiliation(s)
- Erika Aloi
- Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Caterina M Tone
- Department of Physics, University of Calabria, 87036 Rende, Italy; CNR Nanotec c/o Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Riccardo C Barberi
- Department of Physics, University of Calabria, 87036 Rende, Italy; CNR Nanotec c/o Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Federica Ciuchi
- CNR Nanotec c/o Department of Physics, University of Calabria, 87036 Rende, Italy.
| | - Rosa Bartucci
- Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Rende, Italy.
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12
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Zambrano P, Jemiola-Rzeminska M, Muñoz-Torrero D, Suwalsky M, Strzalka K. A rhein-huprine hybrid protects erythrocyte membrane integrity against Alzheimer's disease related Aβ(1-42) peptide. Biophys Chem 2023; 300:107061. [PMID: 37307659 DOI: 10.1016/j.bpc.2023.107061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/26/2023] [Accepted: 06/02/2023] [Indexed: 06/14/2023]
Abstract
Alzheimer's disease remains largely unknown, and currently there is no complete cure for the disease. New synthetic approaches have been developed to create multi-target agents, such as RHE-HUP, a rhein-huprine hybrid which can modulate several biological targets that are relevant to the development of the disease. While RHE-HUP has shown in vitro and in vivo beneficial effects, the molecular mechanisms by which it exerts its protective effect on cell membranes have not been fully clarified. To better understand RHE-HUP interactions with cell membranes, we used synthetic membrane models and natural models of human membranes. For this purpose, human erythrocytes and molecular model of its membrane built-up of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) were used. The latter correspond to classes of phospholipids present in the outer and inner monolayers of the human erythrocyte membrane, respectively. X-ray diffraction and differential scanning calorimetry (DSC) results indicated that RHE-HUP was able to interact mainly with DMPC. In addition, scanning electron microscopy (SEM) analysis showed that RHE-HUP modified the normal biconcave shape of erythrocytes inducing the formation of echinocytes. Moreover, the protective effect of RHE-HUP against the disruptive effect of Aβ(1-42) on the studied membrane models was tested. X-ray diffraction experiments showed that RHE-HUP induced a recovery in the ordering of DMPC multilayers after the disruptive effect of Aβ(1-42), confirming the protective role of the hybrid.
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Affiliation(s)
- Pablo Zambrano
- Facultad de Ciencias Químicas, Universidad de Concepción, Concepción, Chile.
| | - Malgorzata Jemiola-Rzeminska
- Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Diego Muñoz-Torrero
- Laboratory of Medicinal Chemistry (CSIC Associated Unit), Faculty of Pharmacy and Food Sciences, University of Barcelona, Barcelona, Spain; Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
| | - Mario Suwalsky
- Facultad de Medicina, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Kazimierz Strzalka
- Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
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13
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Krishnarjuna B, Marte J, Ravula T, Ramamoorthy A. Enhancing the stability and homogeneity of non-ionic polymer nanodiscs by tuning electrostatic interactions. J Colloid Interface Sci 2023; 634:887-896. [PMID: 36566634 PMCID: PMC10838601 DOI: 10.1016/j.jcis.2022.12.112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
The nanodisc technology is increasingly used for structural studies on membrane proteins and drug delivery. The development of synthetic polymer nanodiscs and the recent discovery of non-ionic inulin-based polymers have significantly broadened the scope of nanodiscs. While the lipid exchange and size flexibility properties of the self-assembled polymer-based nanodiscs are valuable for various applications, the non-ionic polymer nanodiscs are remarkably unique in that they enable the reconstitution of any protein, protein-protein complexes, or drugs irrespective of their charge. However, the non-ionic nature of the belt could influence the stability and size homogeneity of inulin-based polymer nanodiscs. In this study, we investigate the size stability and homogeneity of nanodiscs formed by non-ionic lipid-solubilizing polymers using different biophysical methods. Polymer nanodiscs containing zwitterionic DMPC and different ratios of DMPC:DMPG lipids were made using anionic SMA-EA or non-ionic pentyl-inulin polymers. Non-ionic polymer nanodiscs made using zwitterionic DMPC lipids produced a very broad elution profile on SEC due to their instability in the column, thus affecting sample monodispersity which was confirmed by DLS experiments that showed multiple peaks. However, the inclusion of anionic DMPG lipids improved the stability as observed from SEC and DLS profiles, which was further confirmed by TEM images. Whereas, anionic SMA-EA-based DMPC-nanodiscs showed excellent stability and size homogeneity when solubilizing zwitterionic lipids. The stability of DMPC:DMPG non-ionic polymer nanodiscs is attributed to the inter-nanodisc repulsion by the anionic-DMPG that prevents the uncontrolled collision and fusion of nanodiscs. Thus, the reported results demonstrate the use of electrostatic interactions to tune the solubility, stability, and size homogeneity of non-ionic polymer nanodiscs which are important features for enabling functional and atomic-resolution structural studies of membrane proteins, other lipid-binding molecules, and water-soluble biomolecules including cytosolic proteins, nucleic acids and metabolites.
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Affiliation(s)
- Bankala Krishnarjuna
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Joseph Marte
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Thirupathi Ravula
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA.
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14
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Lenz J, Larsen AH, Keller S, Luchini A. Effect of Cholesterol on the Structure and Composition of Glyco-DIBMA Lipid Particles. Langmuir 2023; 39:3569-3579. [PMID: 36854196 PMCID: PMC10018766 DOI: 10.1021/acs.langmuir.2c03019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Different amphiphilic co-polymers have been introduced to produce polymer-lipid particles with nanodisc structure composed of an inner lipid bilayer and polymer chains self-assembled as an outer belt. These particles can be used to stabilize membrane proteins in solution and enable their characterization by means of biophysical methods, including small-angle X-ray scattering (SAXS). Some of these co-polymers have also been used to directly extract membrane proteins together with their associated lipids from native membranes. Styrene/maleic acid and diisobutylene/maleic acid are among the most commonly used co-polymers for producing polymer-lipid particles, named SMALPs and DIBMALPs, respectively. Recently, a new co-polymer, named Glyco-DIBMA, was produced by partial amidation of DIBMA with the amino sugar N-methyl-d-glucosamine. Polymer-lipid particles produced with Glyco-DIBMA, named Glyco-DIBMALPs, exhibit improved structural properties and stability compared to those of SMALPs and DIBMALPs while retaining the capability of directly extracting membrane proteins from native membranes. Here, we characterize the structure and lipid composition of Glyco-DIBMALPs produced with either 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) or 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). Glyco-DIBMALPs were also prepared with mixtures of either POPC or DMPC and cholesterol at different mole fractions. We estimated the lipid content in the Glyco-DIBMALPs and determined the particle structure and morphology by SAXS. We show that the Glyco-DIBMALPs are nanodisc-like particles whose size and shape depend on the polymer/lipid ratio. This is relevant for designing nanodisc particles with a tunable diameter according to the size of the membrane protein to be incorporated. We also report that the addition of >20 mol % cholesterol strongly perturbed the formation of Glyco-DIBMALPs. Altogether, we describe a detailed characterization of the Glyco-DIBMALPs, which provides relevant inputs for future application of these particles in the biophysical investigation of membrane proteins.
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Affiliation(s)
- Julia Lenz
- Molecular
Biophysics, Technische Universität
Kaiserslautern, Erwin-Schrödinger-Strasse
13, 67663 Kaiserslautern, Germany
| | | | - Sandro Keller
- Biophysics,
Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstrasse 50/III, 8010 Graz, Austria
- Field
of Excellence BioHealth, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Alessandra Luchini
- European
Spallation Source - ERIC, Partikel Gatan, Lund 224
84, Sweden
- Department
of Physics and Geology, University of Perugia, Via Alessandro Pascoli, 06123 Perugia, Italy
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15
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Stengel D, Thai R, Li Y, Peters NM, Holland GP. Biphasic nature of lipid bilayers assembled on silica nanoparticles and evidence for an interdigitated phase. Soft Matter 2023; 19:1882-1889. [PMID: 36799359 DOI: 10.1039/d2sm01517j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Functionalizing silica nanoparticles with a lipid bilayer shell is a common first step in fabricating drug delivery and biosensing devices that are further decorated with other biomolecules for a range of nanoscience applications and therapeutics. Although the molecular structure and dynamics of lipid bilayers have been thoroughly investigated on larger 100 nm-1 μm silica spheres where the lipid bilayer exhibits the typical Lα bilayer phase, the molecular organization of lipids assembled on mesoscale (4-100 nm diameter) nanoparticles is scarce. Here, DSC, TEM and 2H and 31P solid-state NMR are implemented to probe the organization of 1,2-dipalmitoyl-d54-glycero-3-phosphocholine (DMPC-d54) assembled on mesoscale silica nanoparticles illustrating a significant deviation from Lα bilayer structure due to the increasing curvature of mesoscale supports. A biphasic system is observed that exhibits a combination of high-curvature, non-lamellar and lamellar phases for mesoscale (<100 nm) supports with evidence of an interdigitated phase on the smallest diameter support (4 nm).
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Affiliation(s)
- Dillan Stengel
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego CA, 92182-1030, USA.
| | - Rich Thai
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego CA, 92182-1030, USA.
| | - Yuan Li
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego CA, 92182-1030, USA.
| | - Nikki M Peters
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego CA, 92182-1030, USA.
| | - Gregory P Holland
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego CA, 92182-1030, USA.
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16
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Díaz-Rodríguez TG, Celaya CA, Muñiz J. First principles study on the potential of functionalized porous silicon to capture adverse agents to human health: The role played by the interface interactions. Biophys Chem 2023; 292:106910. [PMID: 36327692 DOI: 10.1016/j.bpc.2022.106910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/10/2022] [Accepted: 10/16/2022] [Indexed: 11/06/2022]
Abstract
Porous Silicon (PSi) is an ideal material to build biosensors due to its large surface area and biocompatibility. However, it lacks of selectivity. By adhering bilayer lipids, active sites are added for vital biochemical processes. Such processes are promoted by different proteins, which aid to detect pollutants and drugs, among other. The present work is a systematic theoretical study at the density functional theory level on PSi models, functionalized with H and OH. Several concentrations of such functional groups were assessed at the pores to elucidate the reactivity via Fukui indexes of electrophilic and nucleophilic attack. The 1,2-dimyristoyl-sn-glycero-3-phosphocholine(DMPC) lipid was used as a probe system to interact with the PSi. The attraction was evaluated as electrostatic with a van der Waals contribution. The adsorption was highly selective to the degree of functionalization at the pore. The PSi facets (100) and (001) showed different mechanisms of interaction with the DMPC lipid. The theoretical absorption spectra addressed that the DMPC lipid could be identified with intensity variations coming from the degree of functionalization at the pore, which may be further rationalized experimentally. The present methodology may aid to tailor novel materials to capture and identify adverse agents present in the environment.
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Affiliation(s)
- T G Díaz-Rodríguez
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Priv. Xochicalco s/n, Col. Centro, Temixco CP 62580, Morelos, Mexico.
| | - Christian A Celaya
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Priv. Xochicalco s/n, Col. Centro, Temixco CP 62580, Morelos, Mexico
| | - Jesús Muñiz
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Priv. Xochicalco s/n, Col. Centro, Temixco CP 62580, Morelos, Mexico.
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17
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Leite WC, Wu Y, Pingali SV, Lieberman RL, Urban VS. Change in Morphology of Dimyristoylphosphatidylcholine/Bile Salt Derivative Bicelle Assemblies with Dodecylmaltoside in the Disk and Ribbon Phases. J Phys Chem Lett 2022; 13:9834-9840. [PMID: 36250687 DOI: 10.1021/acs.jpclett.2c02445] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Bicelles, composed of a mixture of long and short chain lipids, form nanostructured molecular assemblies that are attractive lipid-membrane mimics for in vitro studies of integral membrane proteins. Here we study the effect of a third component, the single chain detergent n-dodecyl-β-d-maltoside (DDM) on the morphology of bicelles composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonate (CHAPSO) below (10 °C) and above (38 °C) the phase transition. In the absence of DDM, bicelles convert from ellipsoidal disks at 10 °C to extended ribbon-like structures at 38 °C. The addition of DDM reshapes the ellipsoidal disc to a circular one and the flattened ribbon to a circular-cylinder worm-like micelle. Knowledge of the influence of the single chain detergent DDM on bicelle nanoscale morphology contributes toward comprehending lipid membrane self-organization and to the goal of optimizing lipid mimics for membrane biology research.
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Affiliation(s)
- Wellington C Leite
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - Yuqi Wu
- School of Chemistry & Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332-0400, United States
| | - Sai Venkatesh Pingali
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - Raquel L Lieberman
- School of Chemistry & Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332-0400, United States
| | - Volker S Urban
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
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18
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Selyutina OY, Babailov SP. Holmium Complex with Phospholipids as 1H NMR Relaxational Sensor of Temperature and Viscosity. Molecules 2022; 27:molecules27196691. [PMID: 36235229 PMCID: PMC9573588 DOI: 10.3390/molecules27196691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022]
Abstract
The sensitivity of Ho-phospholipid complexes to changes in the membrane viscosity of liposomes was checked. An increase in viscosity was observed for DPPC and DMPC near the phase-transition temperature. Ho-phospholipid complexes could be used as sensors of local membrane viscosity in NMR and MRI technologies.
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Affiliation(s)
- Olga Yu. Selyutina
- Institute of Chemical Kinetics and Combustion, Institutskaya St. 3, 630090 Novosibirsk, Russia
- Institute of Solid State Chemistry and Mechanochemistry, Kutateladze St. 18, 630128 Novosibirsk, Russia
- Correspondence:
| | - Sergei P. Babailov
- A. V. Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Av. Lavrentyev 3, 630090 Novosibirsk, Russia
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19
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Ángeles-Robles G, Ortiz-Dosal LC, Aranda-Espinoza H, Olivares-Illana V, Arauz-Lara JL, Aranda-Espinoza S. Actin protein inside DMPC GUVs and its mechanical response to AC electric fields. Biochim Biophys Acta Biomembr 2022; 1864:183883. [PMID: 35181295 DOI: 10.1016/j.bbamem.2022.183883] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/10/2022] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
Cells are dynamic systems with complex mechanical properties, regulated by the presence of different species of proteins capable to assemble (and disassemble) into filamentous forms as required by different cells functions. Giant unilamellar vesicles (GUVs) of DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) are systems frequently used as a simplified model of cells because they offer the possibility of assaying separately different stimuli, which is no possible in living cells. Here we present a study of the effect of acting protein on mechanical properties of GUVs, when the protein is inside the vesicles in either monomeric G-actin or filamentous F-actin. For this, rabbit skeletal muscle G-actin is introduced inside GUVs by the electroformation method. Protein polymerization inside the GUVs is promoted by adding to the solution MgCl2 and the ion carrier A23187 to allow the transport of Mg+2 ions into the GUVs. To determine how the presence of actin changes the mechanical properties of GUVs, the vesicles are deformed by the application of an AC electric field in both cases with G-actin and with polymerized F-actin. The changes in shape of the vesicles are characterized by optical microscopy and from them the bending stiffness of the membrane are determined. It is found that G-actin has no appreciable effect on the bending stiffness of DMPC GUVs, but the polymerized actin makes the vesicles more rigid and therefore more resistant to deformations. This result is supported by evidence that actin filaments tend to accumulate near the membrane.
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Affiliation(s)
- Gabriela Ángeles-Robles
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, S. L. P., Mexico
| | - Luis Carlos Ortiz-Dosal
- Unidad Académica de Ingeniería I, Universidad Autónoma de Zacatecas, Zacatecas, Zac., Mexico
| | - H Aranda-Espinoza
- Fischell Department of Bioengineering, University of Maryland, College Park, United States of America
| | - Vanesa Olivares-Illana
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, S. L. P., Mexico
| | - José Luis Arauz-Lara
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, S. L. P., Mexico
| | - S Aranda-Espinoza
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, S. L. P., Mexico.
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20
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Abstract
Structural studies of membrane proteins in native-like environments require the development of diverse membrane mimetics. Currently there is a need for nanodiscs formed with nonionic belt molecules to avoid nonphysiological electrostatic interactions between the membrane system and protein of interest. Here, we describe the formation of lipid nanodiscs from the phospholipid DMPC and a class of nonionic glycoside natural products called saponins. The morphology, surface characteristics, and magnetic alignment properties of the saponin nanodiscs were characterized by light scattering and solid-state NMR experiments. We determined that preparing nanodiscs with high saponin/lipid ratios reduced their size, diminished their ability to spontaneously align in a magnetic field, and favored insertion of individual saponin molecules in the lipid bilayer surface. Further, purification of saponin nanodiscs allowed flipping of the orientation of aligned nanodiscs by 90°. Finally, we found that aligned saponin nanodiscs provide a sufficient alignment medium to allow the measurement of residual dipolar couplings (RDCs) in aqueous cytochrome c.
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Affiliation(s)
- Samuel D. McCalpin
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Thirupathi Ravula
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
- Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
- Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Corresponding Author:
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21
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Chen J, Tieleman DP, Liang Q. Effects of Lid Domain Structural Changes on the Interactions between Peripheral Myelin Protein 2 and a Lipid Bilayer. J Phys Chem Lett 2022; 13:991-996. [PMID: 35060724 DOI: 10.1021/acs.jpclett.1c03961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Peripheral myelin protein 2 (P2) plays an important role in the stacking of the myelin membrane and lipid transport. Here we investigate the interactions between P2 and a model myelin membrane using molecular dynamics simulations, focusing on the effect of the L27D mutation and conformational changes in the α2-helix in the lid domain of P2. The L27D mutation weakens the binding of the lid domain of P2 on the membrane. The α2-helix is either folded or unfolded on the membrane. Compared with the α2-helix structure in water, the membrane stabilizes the structure of the α2-helix, whereas the unfolding of the α2-helix reduces the binding affinity of P2 on the membrane. These findings reveal the energetics of the mutant and the structural changes of P2 on the interactions between the protein and the lipid bilayer and help us to understand the microscopic mechanism of the formation of the myelin sheath structure and some neurological disorders.
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Affiliation(s)
- Jinyu Chen
- Center for Statistical and Theoretical Condensed Matter Physics and Department of Physics, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - D Peter Tieleman
- Centre for Molecular Simulations and Department of Biological Science, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Qing Liang
- Center for Statistical and Theoretical Condensed Matter Physics and Department of Physics, Zhejiang Normal University, Jinhua 321004, P. R. China
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22
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Abstract
Sugars function as bioprotectants by stabilizing biomolecules during dehydration, thermal stress, and freeze-thaw cycles. A buildup of sugars occurs in many organisms upon their exposure to extreme conditions. Understanding sugar's bioprotective effects on membranes is achieved by characterizing the H-bond networks at the lipid-water interface. Here, we report the headgroup H-bond populations, structures, and dynamics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine vesicles in concentrated glucose solutions using ultrafast two-dimensional infrared spectroscopy in conjunction with molecular dynamics simulations. H-Bond populations and dynamics at the ester carbonyl positions are largely unaffected even at very high, 600 mg/mL, sugar concentrations. In addition, dynamics exhibit a slight nonmonotonic dependence on sugar concentration. Simulations, which are in near-quantitative agreement with measured dynamics, show that the H-bond structure remains largely intact by the existence of sugar. This study shows that the bioprotection of sugar is realized through stable lipid-saccharide-water H-bond networks at the membrane interface that mimic the H-bond networks in pure water.
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Affiliation(s)
- Xiao You
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Euihyun Lee
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Cong Xu
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Carlos R Baiz
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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23
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Hashimoto M, Murai Y, Morita K, Kikukawa T, Takagi T, Takahashi H, Yokoyama Y, Amii H, Sonoyama M. Comparison of functionality and structural stability of bacteriorhodopsin reconstituted in partially fluorinated dimyristoylphosphatidylcholine liposomes with different perfluoroalkyl chain lengths. Biochim Biophys Acta Biomembr 2021; 1863:183686. [PMID: 34175295 DOI: 10.1016/j.bbamem.2021.183686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 11/19/2022]
Abstract
Amphiphilic molecules with one or more perfluoroalkyl groups (Rf, CnF2n+1), which show peculiar interfacial properties, are attracting much attention in membrane protein science. We recently have developed a partially fluorinated dimyristoylphosphatidylcholine (DMPC) with a perfluorobutyl group in the hydrophobic chain terminal (F4-DMPC) and demonstrated that F4-DMPC is a promising material for incorporating membrane proteins. Moreover, we have found out that membrane properties of a series of partially fluorinated DMPCs with different Rf chain lengths (Fn-DMPCs) vary in a significant Rf chain length-dependent manner. In the present study, structural and functional properties of a membrane protein bacteriorhodopsin (bR) in the Fn-DMPC (n = 4, 6, and 8) membranes (bR/Fn-DMPC) are investigated using several physicochemical techniques. Regardless of the Rf chain lengths, bR/Fn-DMPCs retain native-like structural and functional properties at 30 °C, unlike bR molecules in DMPC vesicles. In particular, bR/F6-DMPC, which is in the fluid phase at 30 °C, shows flash-induced transient absorption changes very similar to the native purple membrane (PM) and very high thermal stability of bR trimers comparable to the PM. Structural and functional properties of bR/Fn-DMPCs are discussed compared to the PM and bR/DMPC.
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Affiliation(s)
- Mami Hashimoto
- Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Yuka Murai
- Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Kohei Morita
- Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Takashi Kikukawa
- Department of Functional Life Science, Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Toshiyuki Takagi
- Cellular and Molecular Biotechnology Research Institute, AIST, Tsukuba, Ibaraki 305-8565, Japan.
| | - Hiroshi Takahashi
- Division of Pure and Applied Science, Faculty of Science and Technology, Gunma University, Maebashi, Gunma 371-8510, Japan.
| | - Yasunori Yokoyama
- Department of Applied Physics, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Hideki Amii
- Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan; Gunma University Initiative for Advanced Research (GIAR), Kiryu, Gunma 376-8515, Japan
| | - Masashi Sonoyama
- Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan; Gunma University Initiative for Advanced Research (GIAR), Kiryu, Gunma 376-8515, Japan; Gunma University Center for Food Science and Wellness (GUCFW), Gunma University, Kiryu, Gunma 376-8515, Japan.
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24
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Abstract
Self-assembly of amyloid-β (Aβ) peptides in nonequilibrium, flowing conditions is associated with pathogenesis of Alzheimer's disease. We examined the role of biologically relevant, nonequilibrium, flowing conditions in the desorption, diffusion, and integration of Aβ-lipid assemblies at the membrane surface using a microchannel connected with microsyringes. A 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayer was formed on a glass substrate and incubated in Aβ solution under either a quiescent condition (no flow) or flowing condition for 24 h. Although dot-like aggregates (<1 μm) comprising Aβ fibrils formed on the DMPC membrane under the quiescent condition, larger plaque-like aggregates formed under the flowing condition, suggesting that nonequilibrium continuous flow governs the cytotoxicity of Aβ species. We propose that Aβ adsorption on the membrane surface involves spontaneous desorption of Aβ-lipid to form self-assembling aggregates, with this accelerated by surface shear forces. These findings suggest that nonequilibrium, flowing conditions influence inter/intra-molecular Aβ-fibril formation to trigger formation of amyloid plaques.
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Affiliation(s)
- Akane Iida
- Department of Material and Biological Chemistry, Graduate School of Science and Engineering, Yamagata University, 1-4-12, Kojirakawa, Yamagata 990-8560, Japan
| | - Mitsuhiro Abe
- Department of Material and Biological Chemistry, Graduate School of Science and Engineering, Yamagata University, 1-4-12, Kojirakawa, Yamagata 990-8560, Japan
| | - Miona Nochi
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560, Japan
| | - Chiaki Soga
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560, Japan
| | - Kei Unoura
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560, Japan
| | - Hideki Nabika
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560, Japan
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25
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Oganesyan I, Lento C, Tandon A, Wilson DJ. Conformational Dynamics of α-Synuclein during the Interaction with Phospholipid Nanodiscs by Millisecond Hydrogen-Deuterium Exchange Mass Spectrometry. J Am Soc Mass Spectrom 2021; 32:1169-1179. [PMID: 33784451 DOI: 10.1021/jasms.0c00463] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Both normal and pathological functions of α-synuclein (αSN), an abundant protein in the central and peripheral nervous system, have been linked to its interaction with membrane lipid bilayers. The ability to characterize structural transitions of αSN upon membrane complexation will clarify molecular mechanisms associated with αSN-linked pathologies, including Parkinson's disease (PD), multiple systems atrophy, and other synucleinopathies. In this work, time-resolved electrospray ionization hydrogen/deuterium exchange mass spectrometry (TRESI-HDX-MS) was employed to acquire a detailed picture of αSN's conformational transitions as it undergoes complexation with nanodisc membrane mimics with different headgroup charges (zwitterionic DMPC and negative POPG). Using this approach, αSN interactions with DMPC nanodiscs were shown to be rapid exchanging and to have little impact on the αSN conformational ensemble. Interactions with nanodiscs containing lipids known to promote amyloidogenesis (e.g., POPG), on the other hand, were observed to induce substantial and specific changes in the αSN conformational ensemble. Ultimately, we identify a region corresponding residues 19-28 and 45-57 of the αSN sequence that is uniquely impacted by interactions with "amyloidogenic" lipid membranes, supporting the existing "broken-helix" model for α-synuclein/membrane interactions, but do not detect a "helical extension" that is also thought to play a role in αSN aggregation.
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Affiliation(s)
- Irina Oganesyan
- Department of Chemistry, York University, Toronto M3J 1P3, Canada
| | - Cristina Lento
- Department of Chemistry, York University, Toronto M3J 1P3, Canada
| | - Anurag Tandon
- Department of Medicine, University of Toronto, Toronto M5S 1A1, Canada
| | - Derek J Wilson
- Department of Chemistry, York University, Toronto M3J 1P3, Canada
- Centre for Research in Mass Spectrometry, York University, Toronto M3J 1P3, Canada
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26
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Martí J, Lu H. Microscopic Interactions of Melatonin, Serotonin and Tryptophan with Zwitterionic Phospholipid Membranes. Int J Mol Sci 2021; 22:2842. [PMID: 33799606 PMCID: PMC8001758 DOI: 10.3390/ijms22062842] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 12/15/2022] Open
Abstract
The interactions at the atomic level between small molecules and the main components of cellular plasma membranes are crucial for elucidating the mechanisms allowing for the entrance of such small species inside the cell. We have performed molecular dynamics and metadynamics simulations of tryptophan, serotonin, and melatonin at the interface of zwitterionic phospholipid bilayers. In this work, we will review recent computer simulation developments and report microscopic properties, such as the area per lipid and thickness of the membranes, atomic radial distribution functions, angular orientations, and free energy landscapes of small molecule binding to the membrane. Cholesterol affects the behaviour of the small molecules, which are mainly buried in the interfacial regions. We have observed a competition between the binding of small molecules to phospholipids and cholesterol through lipidic hydrogen-bonds. Free energy barriers that are associated to translational and orientational changes of melatonin have been found to be between 10-20 kJ/mol for distances of 1 nm between melatonin and the center of the membrane. Corresponding barriers for tryptophan and serotonin that are obtained from reversible work methods are of the order of 10 kJ/mol and reveal strong hydrogen bonding between such species and specific phospholipid sites. The diffusion of tryptophan and melatonin is of the order of 10-7 cm2/s for the cholesterol-free and cholesterol-rich setups.
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Affiliation(s)
- Jordi Martí
- Department of Physics, Technical University of Catalonia-Barcelona Tech, 08034 Barcelona, Spain
| | - Huixia Lu
- School of Pharmacy, Shanghai Jiaotong University, Shanghai 200240, China;
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27
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Mandala VS, McKay MJ, Shcherbakov AA, Dregni AJ, Kolocouris A, Hong M. Structure and drug binding of the SARS-CoV-2 envelope protein transmembrane domain in lipid bilayers. Nat Struct Mol Biol 2020; 27:1202-1208. [PMID: 33177698 PMCID: PMC7718435 DOI: 10.1038/s41594-020-00536-8] [Citation(s) in RCA: 235] [Impact Index Per Article: 58.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 10/28/2020] [Indexed: 12/19/2022]
Abstract
An essential protein of the SARS-CoV-2 virus, the envelope protein E, forms a homopentameric cation channel that is important for virus pathogenicity. Here we report a 2.1-Å structure and the drug-binding site of E's transmembrane domain (ETM), determined using solid-state NMR spectroscopy. In lipid bilayers that mimic the endoplasmic reticulum-Golgi intermediate compartment (ERGIC) membrane, ETM forms a five-helix bundle surrounding a narrow pore. The protein deviates from the ideal α-helical geometry due to three phenylalanine residues, which stack within each helix and between helices. Together with valine and leucine interdigitation, these cause a dehydrated pore compared with the viroporins of influenza viruses and HIV. Hexamethylene amiloride binds the polar amino-terminal lumen, whereas acidic pH affects the carboxy-terminal conformation. Thus, the N- and C-terminal halves of this bipartite channel may interact with other viral and host proteins semi-independently. The structure sets the stage for designing E inhibitors as antiviral drugs.
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Affiliation(s)
- Venkata S Mandala
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Matthew J McKay
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Aurelio J Dregni
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Antonios Kolocouris
- Department of Pharmaceutical Chemistry, National and Kapodistrian University of Athens, Panepistimioupolis Zografou, Athens, Greece
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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28
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Siddiquee AM, Houri A, Messalea KA, Lin J, Daeneke T, Abbey B, Mechler A, Kou S. Nanoscale Probing of Cholesterol-Rich Domains in Single Bilayer Dimyristoyl-Phosphocholine Membranes Using Near-Field Spectroscopic Imaging. J Phys Chem Lett 2020; 11:9476-9484. [PMID: 33108191 DOI: 10.1021/acs.jpclett.0c02192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cholesterol is believed to induce the formation of membrane domains, "rafts", which are implicated in a range of natural and pathologic membrane processes. Therefore, it is important to understand the role that cholesterol plays in the formation of these structures. Here, we use label-free spectroscopic imaging to investigate cholesterol fractioning in supported bilayer membranes at nanoscale. Scattering-type scanning near-field optical microscopy (s-SNOM) was used to visualize the formation of cholesterol-induced domains in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) membranes. Our results revealed the coexistence of phase separated domains in DMPC lipids with 10 mol % cholesterol content, whereas a mostly homogeneous bilayer was found at low (5 mol %) and high (15 mol %) cholesterol content. Near-field nano-FTIR spectroscopy was used to identify the cholesterol-rich domains based on their qualitative chemical compositions. It was determined that cholesterol binds to phosphodiester and alkyl glycerol ester moieties, likely via hydrogen bonding of the alcohol to either of the ester oxygens. The results also confirm the existence of an ideal cholesterol-lipid mixture ratio (∼15:85) with a geometrically defined packing. At lower cholesterol content there is phase separation between liquid ordered and almost neat DMPC domains. Thus, the liquid ordered phase exists at an energy minimum at a given lipid-cholesterol ratio.
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Affiliation(s)
- Arif M Siddiquee
- Department of Electronic Science, Fujian Research Center for Solid-State Lighting, Xiamen University, Xiamen 361005, China
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science (LIMS), La Trobe University, Melbourne, Victoria 3086, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Melbourne, Victoria 3086, Australia
| | - Aamd Houri
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science (LIMS), La Trobe University, Melbourne, Victoria 3086, Australia
| | - Kibret A Messalea
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Jiao Lin
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Torben Daeneke
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Brian Abbey
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science (LIMS), La Trobe University, Melbourne, Victoria 3086, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Melbourne, Victoria 3086, Australia
| | - Adam Mechler
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science (LIMS), La Trobe University, Melbourne, Victoria 3086, Australia
| | - Shanshan Kou
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science (LIMS), La Trobe University, Melbourne, Victoria 3086, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Melbourne, Victoria 3086, Australia
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29
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Yano YF, Tada H, Arakawa E, Voegeli W, Ina T, Uruga T, Matsushita T. Periodic Elastic Motion in a Self-Assembled Monolayer under Spontaneous Oscillations of Surface Tension: Molecules in a Scrum Push Back a Marangoni Flow. J Phys Chem Lett 2020; 11:6330-6336. [PMID: 32663403 DOI: 10.1021/acs.jpclett.0c01205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Regularly recurring phenomena are a common and important part of life. Such rhythmic behaviors are often seen in nonliving systems under far-from-equilibrium conditions. The study of simple nonliving systems provides clues for improving our understanding of the origin of biological rhythms. Here, we focus on the spontaneous oscillation of surface tension associated with an intermittent Marangoni convective flow generated by two types of surfactants, those that are partially soluble (long chain alcohols) and insoluble (lipids) in water. In this system, we find that the collective motions of two surfactants interact with each other in a systematic manner to control a stable periodic motion: the alcohol molecules (donor) produce a Marangoni flow, and the lipid molecules (acceptor) in a monolayer push the flow back. The shape of the surface tension oscillation can be explained by the viscoelastic properties of the acceptor surfactant, whereas the period of the surface tension oscillation has been explained by the physical properties of the donor surfactant. A recently developed time-resolved X-ray surface scattering technique enables the dynamic structure of the water surface under flow to be determined. We have repeatedly observed that lipid molecules at the air-water interface become regularly oriented normal to the surface at every onset of the Marangoni convective flow.
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Affiliation(s)
- Yohko F Yano
- Department of Physics, Kindai University, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Hiroki Tada
- Department of Physics, Kindai University, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Etsuo Arakawa
- Department of Physics, Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei, Tokyo 184-8501, Japan
| | - Wolfgang Voegeli
- Department of Physics, Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei, Tokyo 184-8501, Japan
| | - Toshiaki Ina
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cyo, Sayo-gun, Hyogo 679-5198, Japan
| | - Tomoya Uruga
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cyo, Sayo-gun, Hyogo 679-5198, Japan
| | - Tadashi Matsushita
- Photon Factory, Institute of Materials Structure Science, KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
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30
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Varadarajan V, Desikan R, Ayappa KG. Assessing the extent of the structural and dynamic modulation of membrane lipids due to pore forming toxins: insights from molecular dynamics simulations. Soft Matter 2020; 16:4840-4857. [PMID: 32421131 DOI: 10.1039/d0sm00086h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Infections caused by many virulent bacterial strains are triggered by the release of pore forming toxins (PFTs), which form oligomeric transmembrane pore complexes on the target plasma membrane. The spatial extent of the perturbation to the surrounding lipids during pore formation is relatively unexplored. Using all-atom molecular dynamics simulations, we investigate the changes in the structure and dynamics of lipids in a 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayer in the presence of contrasting PFTs. Cytolysin A (ClyA), an α toxin with its inserted wedge shaped bundle of inserted α helices, induces significant asymmetry across the membrane leaflets in comparison with α hemolysin (AHL), a β toxin. Despite the differences in hydrophobic mismatch and uniquely different topologies of the two oligomers, perturbations to lipid order as reflected in the tilt angle and order parameters and membrane thinning are short ranged, lying within ∼2.5 nm from the periphery of either pore complex, and commensurate with distances typically associated with van der Waals forces. In contrast, the spatial extent of perturbations to the lipid dynamics extends outward to at least 4 nm for both proteins, and the continuous survival probabilities reveal the presence of a tightly bound shell of lipids in this region. Displacement probability distributions show long tails and the distinctly non-Gaussian features reflect the induced dynamic heterogeneity. A detailed profiling of the protein-lipid contacts with tyrosine, tryptophan, lysine and arginine residues shows increased non-polar contacts in the cytoplasmic leaflet for both PFTs, with a higher number of atomic contacts in the case of AHL in the extracellular leaflet due to the mushroom-like topology of the pore complex. The short ranged nature of the perturbations observed in this simple one component membrane suggests inherent plasticity of membrane lipids enabling the recovery of the structure and membrane fluidity even in the presence of these large oligomeric transmembrane protein assemblies. This observation has implications in membrane repair processes such as budding or vesicle fusion events used to mitigate PFT virulence, where the underlying lipid dynamics and fluidity in the vicinity of the pore complex are expected to play an important role.
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Affiliation(s)
- Vadhana Varadarajan
- Department of Chemical Engineering, Indian Institute of Science, Bangalore-560012, India.
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31
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Dalchand N, Cui Q, Geiger FM. Electrostatics, Hydrogen Bonding, and Molecular Structure at Polycation and Peptide:Lipid Membrane Interfaces. ACS Appl Mater Interfaces 2020; 12:21149-21158. [PMID: 31889444 DOI: 10.1021/acsami.9b17431] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Polycation and peptide-modified surfaces represent opportunities for developing potentially novel biocidal materials in a growing effort to combat bacterial resistance to traditional bactericides. It is well-known that the positive charge of these compounds is crucial to their function in biofouling prevention and as antimicrobials; however, methods for quantifying the number of positive charges on surface-bound polycations and peptides are necessary to predict, control, and optimize the design and therefore the utility of these compounds. This Spotlight on Applications reports on such an approach that combines second harmonic generation (SHG) spectroscopy, quartz crystal microbalance with dissipation monitoring (QCM-D), and atomistic simulations to obtain mechanistic insight into polycation-membrane interactions using supported lipid bilayers (SLBs) as our model system. We find that at high surface coverage, the large polycations we surveyed feature a considerably smaller percentage of ionization when compared to the smaller polycations and peptides. At these high charge densities, we suspect a pKa shift of the charged groups to lower charge-charge repulsion as well as the formation of a looplike conformation such that less monomeric units form contact-ion pairs with the bilayer. Our sum frequency generation (SFG) spectroscopy results complement our understanding of the polycation-membrane interaction. At a high density of the polycation poly(allylamine hydrochloride) (PAH), second-order spectral line shapes are consistent with the expulsion of interfacial water molecules possibly due to contact-ion pair formation between PAH and the lipid bilayer. This finding could be essential for understanding the underlying first steps of cell lysis and penetration by polycations and should be explored further.
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Affiliation(s)
- Naomi Dalchand
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60660, United States
| | - Qiang Cui
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Franz M Geiger
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60660, United States
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32
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Abstract
Surface modification of gold nanoparticles (AuNPs) has significant and complicated effects on their interactions with cell membranes. In this study, we used a lipid/polyacetylene (PDA) vesicle sensor as the lipid membrane model to evaluate AuNP-lipid membrane interactions. Based on the colorimetric response (CR) of PDA vesicles before and after incubation with AuNPs, it was found that the interaction was highly dependent on the surface charge of AuNPs. As compared to the positively charged NPs, neutral and zwitterionic NPs adsorbed much less on the lipid membrane. Negatively charged NPs did not induce any noticeable color changes even at high concentrations. A class of cationic AuNPs with different degrees of surface hydrophobicity was further selected to investigate the role of hydrophobicity in interacting with lipid/PDA vesicles, and log(EC50) was employed as the evaluation index. According to the log(EC50)-NP concentration curve, the hydrophobicity of NPs enhanced the lipid membrane affinity, but electrostatic interactions weakened this effect. Finally, different concentrations of bovine serum albumin (BSA) were used to study the effect of the protein corona on NP-lipid membrane interactions. The formation of a NP-protein corona was found to mask the electrostatic interactions, leading to the decrease of the CR values of cationic NPs, and highly hydrophobic NPs were less affected by a low concentration of BSA due to the strong hydrophobic interactions. Although the effect of NP surface properties on their interactions with cells is far more complicated, our study provides a rapid and effective method for the evaluation of the interactions between surface modified AuNPs and lipid membranes.
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Affiliation(s)
- Congcong Gu
- Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China. and Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Yingying Geng
- Department of Chemistry, University of Massachusetts Amherst, 710 N. Pleasant St., Amherst, MA 01003, USA.
| | - Feng Zheng
- Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China. and Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China and Department of Chemistry, University of Massachusetts Amherst, 710 N. Pleasant St., Amherst, MA 01003, USA.
| | - Vincent M Rotello
- Department of Chemistry, University of Massachusetts Amherst, 710 N. Pleasant St., Amherst, MA 01003, USA.
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33
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Abstract
The ability of amphipathic polymers to self-assemble with lipids and form nanodiscs has been a boon for the field of functional reconstitution of membrane proteins. In a field dominated by detergent micelles, a unique feature of polymer nanodiscs is their much-desired ability to align in the presence of an external magnetic field. Magnetic alignment facilitates the application of solid-state nuclear magnetic resonance (NMR) spectroscopy and aids in the measurement of residual dipolar couplings via well-established solution NMR spectroscopy. In this study, we comprehensively investigate the magnetic alignment properties of styrene maleimide quaternary ammonium (SMA-QA) polymer-based nanodiscs by using 31P and 14N solid-state NMR experiments under static conditions. The results reported herein demonstrate the spontaneous magnetic alignment of large-sized (≥20 nm diameter) SMA-QA nanodiscs (also called as macro-nanodiscs) with the lipid bilayer normal perpendicular to the magnetic field direction. Consequently, the orientation of macro-nanodiscs is further shown to flip the alignment axis parallel to the magnetic field direction upon the addition of a paramagnetic lanthanide salt. These results demonstrate the use of SMA-QA polymer nanodiscs for solid-state NMR applications including structural studies on membrane proteins.
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Affiliation(s)
- Thirupathi Ravula
- Biophysics Program and Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - JaeWoong Kim
- Department of Fine Chemistry , Seoul National University of Science and Technology , Seoul 01811 , Republic of Korea
| | - Dong-Kuk Lee
- Department of Fine Chemistry , Seoul National University of Science and Technology , Seoul 01811 , Republic of Korea
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
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34
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Ausili A, Clemente J, Pons-Belda ÓD, de Godos A, Corbalán-García S, Torrecillas A, Teruel JA, Gomez-Fernández JC. Interaction of Vitamin K 1 and Vitamin K 2 with Dimyristoylphosphatidylcholine and Their Location in the Membrane. Langmuir 2020; 36:1062-1073. [PMID: 31927934 DOI: 10.1021/acs.langmuir.9b03552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Vitamin K1 and vitamin K2 play very important biological roles as members of chains of electron transport as antioxidants in membranes and as cofactors for the posttranslational modification of proteins that participate in a number of physiological functions such as coagulation. The interaction of these vitamins with dimyristoylphosphatidylcholine (DMPC) model membranes has been studied by using a biophysical approach. It was observed by using differential scanning calorimetry that both vitamins have a very limited miscibility with DMPC and they form domains rich in the vitamins at high concentrations. Experiments using X-ray diffraction also showed the formation of different phases as a consequence of the inclusion of either vitamin K at temperatures below the phase transition. However, in the fluid state, a homogeneous phase was detected, and a decrease in the thickness of the membrane was accompanied by an increase in the water layer thickness. 2H NMR spectroscopy showed that both vitamins K induced a decrease in the onset of the phase transition, which was bigger for vitamin K1, and both vitamins decreased the order of the membrane as seen through the first moment (M1). 1H NOESY MAS-NMR showed that protons located at the rings or at the beginning of the lateral chain of both vitamins K interacted with a clear preference with protons located in the polar part of DMPC. On the other hand, protons located on the lateral chain have a nearer proximity with the methyl end of the myristoyl chains of DMPC. In agreement with the 2H NMR, ATR-FTIR (attenuated total reflectance Fourier transform infrared spectroscopy) indicated that both vitamins decreased the order parameters of DMPC. It was additionally deduced that the lateral chains of both vitamins were oriented almost in parallel to the myristoyl chains of the phospholipid.
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Affiliation(s)
- Alessio Ausili
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Javier Clemente
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Óscar D Pons-Belda
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Ana de Godos
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Senena Corbalán-García
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Alejandro Torrecillas
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - José A Teruel
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
| | - Juan C Gomez-Fernández
- Departamento de Bioquı́mica y Biologı́a Molecular "A", Facultad de Veterinaria, Regional Campus of International Excellence "Campus Mare Nostrum" , Universidad de Murcia , Apartado de Correos 4021 , E-30080 Murcia , Spain
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35
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Yu J, Mao J, Nagao M, Bu W, Lin B, Hong K, Jiang Z, Liu Y, Qian S, Tirrell M, Chen W. Structure and dynamics of lipid membranes interacting with antivirulence end-phosphorylated polyethylene glycol block copolymers. Soft Matter 2020; 16:983-989. [PMID: 31851201 DOI: 10.1039/c9sm01642b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The structure and dynamics of lipid membranes in the presence of extracellular macromolecules are critical for cell membrane functions and many pharmaceutical applications. The pathogen virulence-suppressing end-phosphorylated polyethylene glycol (PEG) triblock copolymer (Pi-ABAPEG) markedly changes the interactions with lipid vesicle membranes and prevents PEG-induced vesicle phase separation in contrast to the unphosphorylated copolymer (ABAPEG). Pi-ABAPEG weakly absorbs on the surface of lipid vesicle membranes and slightly changes the structure of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) unilamellar vesicles at 37 °C, as evidenced by small angle neutron scattering. X-ray reflectivity measurements confirm the weak adsorption of Pi-ABAPEG on DMPC monolayer, resulting in a more compact DMPC monolayer structure. Neutron spin-echo results show that the adsorption of Pi-ABAPEG on DMPC vesicle membranes increases the membrane bending modulus κ.
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Affiliation(s)
- Jing Yu
- Centre for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, USA. and Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.
| | - Jun Mao
- Centre for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, USA. and Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.
| | - Michihiro Nagao
- NIST Centre for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102, USA and Centre for Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408, USA
| | - Wei Bu
- Centre for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, USA
| | - Binhua Lin
- Centre for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, USA and James Franck Institute, University of Chicago, Chicago, IL 60637, USA
| | - Kunlun Hong
- Centre for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Zhang Jiang
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Yun Liu
- NIST Centre for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102, USA and Department of Chemical and Biomolecular Engineering, Centre for Neutron Science, University of Delaware, Newark, DE 19716, USA
| | - Shuo Qian
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Matthew Tirrell
- Centre for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, USA. and Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.
| | - Wei Chen
- Centre for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, USA. and Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.
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36
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Robertson IM, Klein BA, Sykes BD. Optimizing fluorine labelling for 19F solid-state NMR in oriented biological systems. J Biomol NMR 2020; 74:1-7. [PMID: 31912345 DOI: 10.1007/s10858-019-00296-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 12/31/2019] [Indexed: 06/10/2023]
Abstract
When planning a fluorine labeling strategy for 19F solid state NMR (ssNMR) studies of the structure and/or mobility of fluorine labeled compounds in situ in an oriented biological system, it is important to characterize the NMR properties of the label. This manuscript focuses on the characterization of a selection of aromatic fluorine compounds in dimyristoylphosphatidylcholine bilayers using 19F ssNMR from the standpoint of determining the optimum arrangement of fluorine nuclei on a pendant aromatic ring before incorporation into more complex biological systems.
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Affiliation(s)
- Ian M Robertson
- Ministry of Health, Government of Alberta, Edmonton, AB, T5J 1S6, Canada
| | - Brittney A Klein
- Department of Biochemistry, University of Alberta, Edmonton, AB, T6G2H7, Canada
| | - Brian D Sykes
- Department of Biochemistry, University of Alberta, Edmonton, AB, T6G2H7, Canada.
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37
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Stottrup BL, TigreLazo J, Bagonza VB, Kunz JC, Zasadzinski JA. Comparison of Line Tension Measurement Methods for Lipid Monolayers at Liquid-Liquid Coexistence. Langmuir 2019; 35:16053-16061. [PMID: 31343892 PMCID: PMC6896218 DOI: 10.1021/acs.langmuir.9b01696] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Several methods of measuring the line tension between phase-separated liquid-ordered-liquid -disordered domains in phospholipid-cholesterol systems have been proposed. These experimental techniques are typically internally self-consistent, but the measured line tension values vary widely among these techniques. To date, no measurement of line tension has utilized multiple experimental techniques to look at the same monolayer system. Here we compare two nonperturbative methods, Fourier analysis of boundary fluctuations (BA) and one proposed by Israelachvili involving the analysis of domain size distributions (SD), to extract the line tension in a 70 mol % DMPC/30 mol % dihydrocholesterol (DChol) mixture as a function of surface pressure. We show that BA predicts the expected variation in line tension measurements consistent with the theoretical critical exponent whereas SD does not. From this comparison, we conclude that the size distribution of monolayer domains is metastable and primarily determined by the kinetics of domain nucleation and subsequent aging.
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Affiliation(s)
- Benjamin L. Stottrup
- Department of Physics, Augsburg University, Minneapolis, Minnesota 55454, United States
| | - Juan TigreLazo
- Department of Physics, Augsburg University, Minneapolis, Minnesota 55454, United States
| | - Vision B. Bagonza
- Department of Physics, Augsburg University, Minneapolis, Minnesota 55454, United States
| | - Joan C. Kunz
- Department of Chemistry, Augsburg University, Minneapolis, Minnesota 55454, United States
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38
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Abstract
The characterization of interactions between melatonin, one main ingredient of medicines regulating sleeping rhythms, and basic components of cellular plasma membranes (phospholipids, cholesterol, metal ions and water) is very important to elucidate the main mechanisms for the introduction of melatonin into cells and also to identify its local structure and microscopic dynamics. Molecular dynamics simulations of melatonin inside mixtures of dimyristoylphosphatidylcholine and cholesterol in NaCl solution at physiological concentration have been performed at 303.15 K to systematically explore melatonin-cholesterol, melatonin-lipid and melatonin-water interactions. Properties such as the area per lipid and thickness of the membrane as well as selected radial distribution functions, binding free energies, angular distributions, atomic spectral densities and translational diffusion of melatonin are reported. The presence of cholesterol significantly affects the behavior of melatonin, which is mainly buried into the interfaces of membranes. Introducing cholesterol into the system helps melatonin change from folded to extended configurations more easily. Our results suggest that there exists a competition between the binding of melatonin to phospholipids and to cholesterol by means of hydrogen-bonds. Spectral densities of melatonin reported in this work, in overall good agreement with experimental data, revealed the participation of each atom of melatonin to its complete spectrum. Melatonin self-diffusion coefficients are of the order of 10-7 cm2/s and they significantly increase when cholesterol is addeed to the membrane.
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Affiliation(s)
- Huixia Lu
- Department of Physics, Technical University of Catalonia-Barcelona Tech. Barcelona, Catalonia, Spain
| | - Jordi Martí
- Department of Physics, Technical University of Catalonia-Barcelona Tech. Barcelona, Catalonia, Spain
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39
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Roux M, Bonnet V, Djedaïni-Pilard F. Ordering of Saturated and Unsaturated Lipid Membranes near Their Phase Transitions Induced by an Amphiphilic Cyclodextrin and Cholesterol. Langmuir 2019; 35:14376-14387. [PMID: 31564102 DOI: 10.1021/acs.langmuir.9b02082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
When inserted in membranes of dimyristoyl phosphatidylcholine (DMPC), methylated β-cyclodextrins with one (TrimβMLC) or two (TrimβDLC) lauryl acyl chains grafted onto the hydrophilic cavity exert a "cholesterol-like ordering effect", by straightening the acyl chains in the fluid phase at temperatures near the chain melting transition. This effect may be related to pretransitional events such as the "anomalous swelling" known to occur with saturated phosphatidylcholine membranes. To investigate this model, order profiles and bilayer thicknesses of DMPC and unsaturated 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) membranes containing amphiphilic cyclodextrins or cholesterol were determined by deuterium NMR. The pure lipid membranes display both a qualitatively similar chain ordering upon cooling in the fluid phase, more important at the chain extremity, which gets more pronounced near their fluid-to-gel transitions. Both membranes show a bilayer thickness increase by ∼0.5 Å just above their transition, as observed previously with saturated phosphatidylcholines of various chain lengths. Membrane-insertion of 5% TrimβMLC or cholesterol induces an important ordering of the DMPC acyl chains just above the transition, which is also more pronounced at the chain extremity. There is an additional increase of the bilayer thickness, most probably due to a deep insertion of these amphiphilic molecules, facilitated by increased bilayer softness in the anomalous swelling regime. These effects are more important with TrimβMLC than with cholesterol. By contrast, no enhanced acyl chain ordering was observed when approaching the transition of TrimβMLC-containing POPC membranes, as a possible consequence of an eventual lack of anomalous swelling in unsaturated lipid membranes. Insertion of higher concentrations of TrimβMLC was found to induce a magnetic orientation of the DMPC membranes in the fluid phase with 10% of this derivative, coupled with the appearance of a broad isotropic component when the concentration is raised to 20%. No membrane orientation or isotropic component was detected with TrimβMLC-containing POPC membranes.
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Affiliation(s)
- Michel Roux
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS , Université Paris-Sud, Université Paris-Saclay , F-91198 Gif-sur-Yvette cedex , France
| | - Véronique Bonnet
- LG2A, UMR7378 , Université de Picardie Jules Verne , F-80039 Amiens , France
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40
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Perissinotto F, Rondelli V, Parisse P, Tormena N, Zunino A, Almásy L, Merkel DG, Bottyán L, Sajti S, Casalis L. GM1 Ganglioside role in the interaction of Alpha-synuclein with lipid membranes: Morphology and structure. Biophys Chem 2019; 255:106272. [PMID: 31698188 DOI: 10.1016/j.bpc.2019.106272] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/15/2019] [Indexed: 02/05/2023]
Abstract
Alpha-Synuclein (AS) is the protein playing the major role in Parkinson's disease (PD), a neurological disorder characterized by the degeneration of dopaminergic neurons and the accumulation of AS into amyloid plaques. The aggregation of AS into intermediate aggregates, called oligomers, and their pathological relation with biological membranes are considered key steps in the development and progression of the disease. Here we propose a multi-technique approach to study the effects of AS in its monomeric and oligomeric forms on artificial lipid membranes containing GM1 ganglioside. GM1 is a component of functional membrane micro-domains, called lipid rafts, and has been demonstrated to bind AS in neurons. With the aim to understand the relation between gangliosides and AS, here we exploit the complementarity of microscopy (Atomic Force Microscopy) and neutron scattering (Small Angle Neutron Scattering and Neutron Reflectometry) techniques to analyze the structural changes of two different membranes (Phosphatidylcholine and Phosphatidylcholine/GM1) upon binding with AS. We observe the monomer- and oligomer-interactions are both limited to the external membrane leaflet and that the presence of ganglioside leads to a stronger interaction of the membranes and AS in its monomeric and oligomeric forms with a stronger aggressiveness in the latter. These results support the hypothesis of the critical role of lipid rafts not only in the biofunctioning of the protein, but even in the development and the progression of the Parkinson's disease.
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Affiliation(s)
| | - V Rondelli
- Department of Medical Biotechnologies and Translational Medicine, Università degli Studi di Milano, Milano, Italy.
| | - P Parisse
- Elettra Sincrotrone Trieste S.C.p.A., Trieste, Italy.
| | - N Tormena
- Università degli Studi di Trieste, Trieste, Italy
| | - A Zunino
- Department of Medical Biotechnologies and Translational Medicine, Università degli Studi di Milano, Milano, Italy
| | - L Almásy
- Wigner Research Centre for Physics, Budapest, Hungary
| | - D G Merkel
- Wigner Research Centre for Physics, Budapest, Hungary
| | - L Bottyán
- Wigner Research Centre for Physics, Budapest, Hungary
| | - Sz Sajti
- Wigner Research Centre for Physics, Budapest, Hungary
| | - L Casalis
- Elettra Sincrotrone Trieste S.C.p.A., Trieste, Italy
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41
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Pires F, Geraldo VPN, Rodrigues B, Granada-Flor AD, de Almeida RFM, Oliveira ON, Victor BL, Machuqueiro M, Raposo M. Evaluation of EGCG Loading Capacity in DMPC Membranes. Langmuir 2019; 35:6771-6781. [PMID: 31006246 DOI: 10.1021/acs.langmuir.9b00372] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Catechins are molecules with potential use in different pathologies such as diabetes and cancer, but their pharmaceutical applications are often hindered by their instability in the bloodstream. This issue can be circumvented using liposomes as their nanocarriers for in vivo delivery. In this work, we studied the molecular details of (-)-epigallocatechin-3-gallate (EGCG) interacting with 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC) monolayer/bilayer systems to understand the catechin loading ability and liposome stability, using experimental and computational techniques. The molecular dynamics simulations show the EGCG molecules deep inside the lipid bilayer, positioned below the lipid ester groups, generating a concentration-dependent lipid condensation. This effect was also inferred from the surface pressure isotherms of DMPC monolayers. In the polarization-modulated infrared reflection absorption spectra assays, the predominant effect at higher concentrations of EGCG (e.g., 20 mol %) was an increase in lipid tail disorder. The steady-state fluorescence data confirmed this disordered state, indicating that the catechin-induced liposome aggregation outweighs the condensation effects. Therefore, by adding more than 10 mol % EGCG to the liposomes, a destabilization of the vesicles occurs with the ensuing release of entrapped catechins. The loading capacity for DMPC seems to be limited by its disordered lipid arrangements, typical of a fluid phase. To further increase the clinical usefulness of liposomes, lipid bilayers with more stable and organized assemblies should be employed to avoid aggregation at large concentrations of catechin.
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Affiliation(s)
- Filipa Pires
- Departamento de Física, CEFITEC, Faculdade de Ciências e Tecnologia , Universidade Nova de Lisboa , 2829-516 Caparica , Portugal
| | - Vananélia P N Geraldo
- Instituto de Física de São Carlos , Universidade de São Paulo , 13560-970 Sao Carlos , Brazil
| | - Bárbara Rodrigues
- Departamento de Física, CEFITEC, Faculdade de Ciências e Tecnologia , Universidade Nova de Lisboa , 2829-516 Caparica , Portugal
| | - António de Granada-Flor
- Departamento de Química e Bioquímica, Centro de Química e Bioquímica , Faculdade de Ciências da Universidade de Lisboa , Campo Grande, 1749-016 Lisboa , Portugal
| | - Rodrigo F M de Almeida
- Departamento de Química e Bioquímica, Centro de Química e Bioquímica , Faculdade de Ciências da Universidade de Lisboa , Campo Grande, 1749-016 Lisboa , Portugal
| | - Osvaldo N Oliveira
- Instituto de Física de São Carlos , Universidade de São Paulo , 13560-970 Sao Carlos , Brazil
| | - Bruno L Victor
- Departamento de Química e Bioquímica, Centro de Química e Bioquímica , Faculdade de Ciências da Universidade de Lisboa , Campo Grande, 1749-016 Lisboa , Portugal
| | - Miguel Machuqueiro
- Departamento de Química e Bioquímica, Centro de Química e Bioquímica , Faculdade de Ciências da Universidade de Lisboa , Campo Grande, 1749-016 Lisboa , Portugal
| | - Maria Raposo
- Departamento de Física, CEFITEC, Faculdade de Ciências e Tecnologia , Universidade Nova de Lisboa , 2829-516 Caparica , Portugal
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42
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Sugikawa K, Matsuo K, Ikeda A. Suppression of Gold Nanoparticle Aggregation on Lipid Membranes Using Nanosized Liposomes To Increase Steric Hindrance. Langmuir 2019; 35:229-236. [PMID: 30517012 DOI: 10.1021/acs.langmuir.8b03550] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Suppression of nanoparticle aggregation on a plasma membrane surface may lead to better understanding of the causes of various diseases and development of new drug delivery systems. In this study, we inhibited the aggregation of gold nanoparticles on a lipid membrane in a fluidic liquid-crystalline phase by using nanosized liposomes to increase steric hindrance. Adsorption of liposomes on gold nanoparticles was confirmed by transmission electron microscopy and ultraviolet-visible absorption spectroscopy. The ability of the liposomes to suppress gold nanoparticle aggregation strongly depended on the concentration of liposomes providing steric hindrance. The fluidity or rigidity of the liposome membrane also strongly influenced the ability of the liposomes to suppress gold nanoparticle aggregation.
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Affiliation(s)
- Kouta Sugikawa
- Department of Applied Chemistry, Graduate School of Engineering , Hiroshima University , Higashi-Hiroshima 739-8527 , Japan
| | - Kotaro Matsuo
- Department of Applied Chemistry, Graduate School of Engineering , Hiroshima University , Higashi-Hiroshima 739-8527 , Japan
| | - Atsushi Ikeda
- Department of Applied Chemistry, Graduate School of Engineering , Hiroshima University , Higashi-Hiroshima 739-8527 , Japan
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43
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Zong W, Li Q, Zhang X, Han X. Deformation of giant unilamellar vesicles under osmotic stress. Colloids Surf B Biointerfaces 2018; 172:459-463. [PMID: 30196231 DOI: 10.1016/j.colsurfb.2018.08.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 08/21/2018] [Accepted: 08/26/2018] [Indexed: 12/31/2022]
Abstract
Biological membrane plays an important role in maintaining an osmotic equilibrium between the cytoplasm and the extracellular solution of cells. Here, the giant unilamellar vesicles (GUVs) as cell models were used to investigate the effect of osmotic stress on phospholipid membranes. The deformation of GUVs, including inward budding and outward budding, was systematically investigated by the osmotic press from glucose, sucrose, LiCl, and KCl solutions. The permeability (P) of DMPC, DMPC/10 mol% Chol GUVs, DMPC/25 mol% Chol GUVs, and DMPC/40 mol% Chol GUVs in glucose, sucrose, LiCl, and KCl solutions were all obtained. The P value decreases with the addition of more cholesterol in the bilayer. The monovalent cations caused higher permeability of lipid bilayer membranes due to their combination with phospholipids. The molar flux of water (J) value was found to be the key factor for determining the deformation state from mainly inward budding to mainly outward budding. The findings in this paper may help us to understand cell transformation triggered with osmotic stress.
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Affiliation(s)
- Wei Zong
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, 92 West Da-Zhi Street, Harbin, 150001, China
| | - Qingchuan Li
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, 92 West Da-Zhi Street, Harbin, 150001, China
| | - Xunan Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, 92 West Da-Zhi Street, Harbin, 150001, China
| | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, 92 West Da-Zhi Street, Harbin, 150001, China.
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44
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Sugár IP, Bonanno AP, Chong PLG. Gramicidin Lateral Distribution in Phospholipid Membranes: Fluorescence Phasor Plots and Statistical Mechanical Model. Int J Mol Sci 2018; 19:E3690. [PMID: 30469389 PMCID: PMC6274966 DOI: 10.3390/ijms19113690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 11/16/2022] Open
Abstract
When using small mole fraction increments to study gramicidins in phospholipid membranes, we found that the phasor dots of intrinsic fluorescence of gramicidin D and gramicidin A in dimyristoyl-sn-glycero-3-phosphocholine (DMPC) unilamellar and multilamellar vesicles exhibit a biphasic change with peptide content at 0.143 gramicidin mole fraction. To understand this phenomenon, we developed a statistical mechanical model of gramicidin/DMPC mixtures. Our model assumes a sludge-like mixture of fluid phase and aggregates of rigid clusters. In the fluid phase, gramicidin monomers are randomly distributed. A rigid cluster is formed by a gramicidin dimer and DMPC molecules that are condensed to the dimer, following particular stoichiometries (critical gramicidin mole fractions, Xcr including 0.143). Rigid clusters form aggregates in which gramicidin dimers are regularly distributed, in some cases, even to superlattices. At Xcr, the size of cluster aggregates and regular distributions reach a local maximum. Before a similar model was developed for cholesterol/DMPC mixtures (Sugar and Chong (2012) J. Am. Chem. Soc. 134, 1164⁻1171) and here the similarities and differences are discussed between these two models.
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Affiliation(s)
- István P Sugár
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Alexander P Bonanno
- Department of Medical Genetics and Molecular Biochemistry, The Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
| | - Parkson Lee-Gau Chong
- Department of Medical Genetics and Molecular Biochemistry, The Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
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45
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Abbasi F, Alvarez-Malmagro J, Su Z, Leitch JJ, Lipkowski J. Pore Forming Properties of Alamethicin in Negatively Charged Floating Bilayer Lipid Membranes Supported on Gold Electrodes. Langmuir 2018; 34:13754-13765. [PMID: 30265810 DOI: 10.1021/acs.langmuir.8b02554] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), and photon polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) were employed to investigate the formation of alamethicin pores in negatively charged bilayers composed of a mixture of 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC) and egg-PG floating at gold (111) electrode surfaces modified by self-assembled monolayers of 1-thio-β-d-glucose (β-Tg). The EIS data showed that the presence of alamethicin decreases the membrane resistivity by about 1 order of magnitude. PM-IRRAS measurements provided information about the tilt angles of peptide helical axis with respect to the bilayer normal. The small tilt angles obtained for the peptide helical axis prove that the alamethicin molecules were inserted into the DMPC/egg-PG membranes. The tilt angles decreased when negative potentials were applied, which correlates with the observed decrease in membrane resistivity, indicating that ion pore formation is assisted by the transmembrane potential. Molecular resolution AFM images provided visual evidence that alamethicin molecules aggregate forming hexagonal porous 2D lattices with periodicities of 2.0 ± 0.2 nm. The pore formation by alamethicin in the negatively charged membrane was compared with the interaction of this peptide with a bilayer formed by zwitterionic lipids. The comparison of these results showed that alamethicin preferentially forms ion translocating pores in negatively charged phospholipid membranes.
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Affiliation(s)
- Fatemeh Abbasi
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | | | - ZhangFei Su
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - J Jay Leitch
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Jacek Lipkowski
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
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Sahoo BR, Genjo T, Bekier M, Cox SJ, Stoddard AK, Ivanova M, Yasuhara K, Fierke CA, Wang Y, Ramamoorthy A. Alzheimer's amyloid-beta intermediates generated using polymer-nanodiscs. Chem Commun (Camb) 2018; 54:12883-12886. [PMID: 30379172 PMCID: PMC6247814 DOI: 10.1039/c8cc07921h] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polymethacrylate-copolymer (PMA) encased lipid-nanodiscs (∼10 nm) and macro-nanodiscs (>15 nm) are used to study Aβ1-40 aggregation. We demonstrate that PMA-nanodiscs form a ternary association with Aβ and regulate its aggregation kinetics by trapping intermediates. Results demonstrating the reduced neurotoxicity of nanodisc-bound Aβ oligomers are also reported.
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Affiliation(s)
- Bikash R. Sahoo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
| | - Takuya Genjo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
| | - Michael Bekier
- Department of Neurology, Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Sarah J. Cox
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
| | - Andrea K. Stoddard
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
| | - Magdalena Ivanova
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
| | - Kazuma Yasuhara
- Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 6300192, Japan
| | - Carol A. Fierke
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
- Texas A&M University, College Station, TX 77843, USA
| | - Yanzhuang Wang
- Department of Neurology, Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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Al-Ayoubi SR, Schinkel PKF, Berghaus M, Herzog M, Winter R. Combined effects of osmotic and hydrostatic pressure on multilamellar lipid membranes in the presence of PEG and trehalose. Soft Matter 2018; 14:8792-8802. [PMID: 30339170 DOI: 10.1039/c8sm01343h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We studied the interaction of lipid membranes with the disaccharide trehalose (TRH), which is known to stabilize biomembranes against various environmental stress factors. Generally, stress factors include low/high temperature, shear, osmotic and hydrostatic pressure. Small-angle X-ray-scattering was applied in combination with fluorescence spectroscopy and calorimetric measurements to get insights into the influence of trehalose on the supramolecular structure, hydration level, and elastic and thermodynamic properties as well as phase behavior of the model biomembrane DMPC, covering a large region of the temperature, osmotic and hydrostatic pressure phase space. We observed distinct effects of trehalose on the topology of the lipid's supramolecular structure. Trehalose, unlike osmotic pressure induced by polyethylene glycol, leads to a decrease of lamellar order and a swelling of multilamellar vesicles, which is attributable to direct interactions between the membrane and trehalose. Our results revealed a distinct biphasic concentration dependence of the observed effects of trehalose. While trehalose intercalates between the polar head groups at low concentrations, the effects after saturation are dominated by the exclusion of trehalose from the membrane surface.
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Affiliation(s)
- Samy R Al-Ayoubi
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany.
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Brown AC, Boesze-Battaglia K, Balashova NV, Mas Gómez N, Speicher K, Tang HY, Duszyk ME, Lally ET. Membrane localization of the Repeats-in-Toxin (RTX) Leukotoxin (LtxA) produced by Aggregatibacter actinomycetemcomitans. PLoS One 2018; 13:e0205871. [PMID: 30335797 PMCID: PMC6193665 DOI: 10.1371/journal.pone.0205871] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/02/2018] [Indexed: 12/31/2022] Open
Abstract
The oral bacterium, Aggregatibacter actinomycetemcomitans, which is associated with localized aggressive periodontitis, as well as systemic infections including endocarditis, produces numerous virulence factors, including a repeats-in-toxin (RTX) protein called leukotoxin (LtxA), which kills human immune cells. The strains of A. actinomycetemcomitans most closely associated with disease have been shown to produce the most LtxA, suggesting that LtxA plays a significant role in the virulence of this organism. LtxA, like many of the RTX toxins, can be divided into four functional domains: an N-terminal hydrophobic domain, which contains a significant fraction of hydrophobic residues and has been proposed to play a role in the membrane interaction of the toxin; the central domain, which contains two lysine residues that are the sites of post-translational acylation; the repeat domain that is characteristic of the RTX toxins, and a C-terminal domain thought to be involved in secretion. In its initial interaction with the host cell, LtxA must bind to both cholesterol and an integrin receptor, lymphocyte function-associated antigen-1 (LFA-1). While both interactions are essential for toxicity, the domains of LtxA involved remain unknown. We therefore undertook a series of experiments, including tryptophan quenching and trypsin digestion, to characterize the structure of LtxA upon interaction with membranes of various lipid compositions. Our results demonstrate that LtxA adopts a U-shaped conformation in the membrane, with the N- and C-terminal domains residing outside of the membrane.
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Affiliation(s)
- Angela C. Brown
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Nataliya V. Balashova
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Nestor Mas Gómez
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Kaye Speicher
- Wistar Institute, Philadelphia, PA, United States of America
| | - Hsin-Yao Tang
- Wistar Institute, Philadelphia, PA, United States of America
| | - Margaret E. Duszyk
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Edward T. Lally
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
- * E-mail:
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Miranda C, Booth VK, Morrow MR. Effects of Amphipathic Polypeptides on Membrane Organization Inferred from Studies Using Bicellar Lipid Mixtures. Langmuir 2018; 34:11759-11771. [PMID: 30196696 DOI: 10.1021/acs.langmuir.8b02257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
SP-B63-78, a lung surfactant protein fragment, and magainin 2, an antimicrobial peptide, are amphipathic peptides with the same overall charge but different biological functions. Deuterium nuclear magnetic resonance has been used to compare the interactions of these peptides with dispersions of 1,2-dimyristoyl- sn-glycero-3-phophocholine (DMPC)/1,2-dihexanoyl- sn-glycero-3-phophocholine (DHPC) (4:1) and DMPC/1,2-dimyristoyl- sn-glycero-3-phopho-(1'-rac-glycerol) (DMPG)/DHPC (3:1:1), two mixtures of long-chain and short-chain lipids that display bicellar behavior. This study exploited the sensitivity of a bicellar system structural organization to factors that modify partitioning of their lipid components between different environments. In small bicelle particles formed at low temperatures, short-chain components preferentially occupy curved rim environments around bilayer disks of the long-chain components. Changes in chain order and lipid mixing, on heating, can drive transitions to more extended assemblies including a magnetically orientable phase at intermediate temperature. In this work, neither peptide had a substantial effect on the behavior of the zwitterionic DMPC/DHPC mixture. For bicellar mixtures containing the anionic lipid DMPG, the peptide SP-B63-78 lowered the temperature at which magnetically orientable particles coalesced into more extended lamellar structures. SP-B63-78 did not promote partitioning of the zwitterionic and anionic long-chain lipid components into different environments. Magainin 2, on the other hand, was found to promote separation of the anionic lipid, DMPG, and the zwitterionic lipid, DMPC, into different environments for temperatures above 34 °C. The contrast between the effects of these two peptides on the lipid mixtures studied appears to be consistent with their functional roles in biological systems.
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Affiliation(s)
- Chris Miranda
- Department of Physics and Physical Oceanography , Memorial University of Newfoundland , St. John's , Newfoundland and Labrador , Canada A1B 3X7
| | - Valerie K Booth
- Department of Biochemistry , Memorial University of Newfoundland , St. John's , Newfoundland and Labrador , Canada A1B 3X9
| | - Michael R Morrow
- Department of Physics and Physical Oceanography , Memorial University of Newfoundland , St. John's , Newfoundland and Labrador , Canada A1B 3X7
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Shahzadi Z, Das S, Bala T, Mukhopadhyay C. Phase Behavior of GM1-Containing DMPC-Cholesterol Monolayer: Experimental and Theoretical Study. Langmuir 2018; 34:11602-11611. [PMID: 30173524 DOI: 10.1021/acs.langmuir.8b02621] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Organization and distribution of lipids in cellular membranes play an important role in a diverse range of biological processes, such as membrane trafficking and signaling. Here, we present the combined experimental and simulated results to elucidate the phase behavioral features of ganglioside monosialo 1 (GM1)-containing mixed monolayer of the lipids 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC) and cholesterol (CHOL). Two monolayers having compositions DMPC-CHOL and GM1-DMPC-CHOL are investigated at air-water and air-solid interfaces using Langmuir-Blodgett experiments and scanning electron microscopy (SEM), respectively, to ascertain the phase behavior change of the monolayers. Surface pressure isotherms and SEM imaging of domain formation indicate that addition of GM1 to the monolayer at low surface pressure causes a fluidization of the system but once the system attains the surface pressure corresponding to its liquid-condensed phase, the monolayer becomes more ordered than the system devoid of GM1 and interacts among each other more cooperatively. Besides, the condensing effect of cholesterol on the DMPC monolayer was also verified by our experiments. Apart from these, the effects induced by GM1 on the phase behavior of the binary mixture of DMPC-CHOL were studied with and without applying liquid-expanded (LE)-liquid-condensed (LC) equilibrium surface pressure using molecular dynamics (MD) simulation. Our molecular dynamics (MD) simulation results give an atomistic-level explanation of our experimental findings and furnish a similar conclusion.
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Affiliation(s)
- Zarrin Shahzadi
- Department of Chemistry , University of Calcutta , 92, A.P.C. Road , Kolkata 700009 , India
| | - Subhasis Das
- Department of Chemistry , University of Calcutta , 92, A.P.C. Road , Kolkata 700009 , India
| | - Tanushree Bala
- Department of Chemistry , University of Calcutta , 92, A.P.C. Road , Kolkata 700009 , India
| | - Chaitali Mukhopadhyay
- Department of Chemistry , University of Calcutta , 92, A.P.C. Road , Kolkata 700009 , India
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