scholarly journals Non-specific interactions between soluble proteins and lipids induce irreversible changes in the properties of lipid bilayers

Soft Matter ◽  
2013 ◽  
Vol 9 (16) ◽  
pp. 4219-4226 ◽  
Author(s):  
Francesca Ruggeri ◽  
Fan Zhang ◽  
Tania Lind ◽  
Erica D. Bruce ◽  
Boris L. T. Lau ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Soluble Proteins ◽  
Specific Interactions

scholarly journals Hydrogen Bond Networks Near Supported Lipid Bilayers from Vibrational Sum Frequency Generation Experiments and Atomistic Simulations

2018 ◽  
Author(s):  
Merve Dogangun ◽  
Paul E. Ohno ◽  
Dongyue Liang ◽  
Alicia C. McGeachy ◽  
Ariana Gray Be ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Lipid Bilayers ◽  
Sum Frequency Generation ◽  
Atomistic Simulations ◽  
Supported Lipid Bilayers ◽  
Water Molecules ◽  
Specific Interactions ◽  
Sum Frequency ◽  
Hydrogen Bond Networks ◽  
Frequency Generation

<div> <div> <p>We report vibrational sum frequency generation (SFG) spectra in which the C–H stretches of lipid alkyl tails in fully hydrogenated single- and dual-component supported lipid bilayers are detected along with the O–H stretching continuum above the bilayer. As the salt concentration is increased from ~10 μM to 0.1 M, the SFG intensities in the O–H stretching region decrease by a factor of 2, consistent with significant absorptive-dispersive mixing between χ(2) and χ(3) contributions to the SFG signal generation process from charged interfaces. A method for estimating the surface potential from the second-order spectral lineshapes (in the OH stretching region) is presented and discussed in the context of choosing truly zero-potential reference states. Aided by atomistic simulations, we find that the strength and orientation distribution of the hydrogen bonds over the purely zwitterionic bilayers are largely invariant between sub-micromolar and hundreds of millimolar concentrations. However, specific interactions between water molecules and lipid headgroups are observed upon replacing phosphocholine (PC) lipids with negatively charged phosphoglycerol (PG) lipids, which coincides with SFG signal intensity reductions in the 3100 cm-1 to 3200 cm-1 frequency region. The atomistic simulations show that this outcome is consistent with a small, albeit statistically significant, decrease in the number of water molecules adjacent to both the lipid phosphate and choline moieties per unit area, supporting the SFG observations. Ultimately, the ability to probe hydrogen-bond networks over lipid bilayers holds the promise of opening paths for understanding, controlling, and predicting specific and non-specific interactions between membranes and ions, small molecules, peptides, polycations, proteins, and coated and uncoated nanomaterials.<br></p></div></div>

scholarly journals Hydrogen Bond Networks Near Supported Lipid Bilayers from Vibrational Sum Frequency Generation Experiments and Atomistic Simulations

2018 ◽  
Author(s):  
Merve Dogangun ◽  
Paul E. Ohno ◽  
Dongyue Liang ◽  
Alicia C. McGeachy ◽  
Ariana Gray Be ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Lipid Bilayers ◽  
Sum Frequency Generation ◽  
Atomistic Simulations ◽  
Supported Lipid Bilayers ◽  
Water Molecules ◽  
Specific Interactions ◽  
Sum Frequency ◽  
Hydrogen Bond Networks ◽  
Frequency Generation

<div> <div> <p>We report vibrational sum frequency generation (SFG) spectra in which the C–H stretches of lipid alkyl tails in fully hydrogenated single- and dual-component supported lipid bilayers are detected along with the O–H stretching continuum above the bilayer. As the salt concentration is increased from ~10 μM to 0.1 M, the SFG intensities in the O–H stretching region decrease by a factor of 2, consistent with significant absorptive-dispersive mixing between χ(2) and χ(3) contributions to the SFG signal generation process from charged interfaces. A method for estimating the surface potential from the second-order spectral lineshapes (in the OH stretching region) is presented and discussed in the context of choosing truly zero-potential reference states. Aided by atomistic simulations, we find that the strength and orientation distribution of the hydrogen bonds over the purely zwitterionic bilayers are largely invariant between sub-micromolar and hundreds of millimolar concentrations. However, specific interactions between water molecules and lipid headgroups are observed upon replacing phosphocholine (PC) lipids with negatively charged phosphoglycerol (PG) lipids, which coincides with SFG signal intensity reductions in the 3100 cm-1 to 3200 cm-1 frequency region. The atomistic simulations show that this outcome is consistent with a small, albeit statistically significant, decrease in the number of water molecules adjacent to both the lipid phosphate and choline moieties per unit area, supporting the SFG observations. Ultimately, the ability to probe hydrogen-bond networks over lipid bilayers holds the promise of opening paths for understanding, controlling, and predicting specific and non-specific interactions between membranes and ions, small molecules, peptides, polycations, proteins, and coated and uncoated nanomaterials.<br></p></div></div>

Model lipid bilayers mimic non-specific interactions of gold nanoparticles with macrophage plasma membranes

2018 ◽  
Vol 516 ◽  
pp. 284-294 ◽  
Author(s):  
Costanza Montis ◽  
Viola Generini ◽  
Giulia Boccalini ◽  
Paolo Bergese ◽  
Daniele Bani ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Lipid Bilayers ◽  
Plasma Membranes ◽  
Specific Interactions

scholarly journals Antibody-Hapten Recognition at the Surface of Functionalized Liposomes Studied by SPR: Steric Hindrance of Pegylated Phospholipids in Stealth Liposomes Prepared for Targeted Radionuclide Delivery

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Eliot. P. Botosoa ◽  
Mike Maillasson ◽  
Marie Mougin-Degraef ◽  
Patricia Remaud-Le Saëc ◽  
Jean-François Gestin ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Steric Hindrance ◽  
Lipid Fraction ◽  
Binding Kinetics ◽  
Specific Interactions ◽  
Pegylated Liposomes ◽  
Stealth Liposomes ◽  
Indium Complex ◽  
Pegylated Lipids ◽  
Pegylated Phospholipids

Targeted PEGylated liposomes could increase the amount of drugs or radionuclides delivered to tumor cells. They show favorable stability and pharmacokinetics, but steric hindrance of the PEG chains can block the binding of the targeting moiety. Here, specific interactions between an antihapten antibody (clone 734, specific for the DTPA-indium complex) and DTPA-indium-tagged liposomes were characterized by surface plasmon resonance (SPR). Non-PEGylated liposomes fused on CM5 chips whereas PEGylated liposomes did not. By contrast, both PEGylated and non-PEGylated liposomes attached to L1 chips without fusion. SPR binding kinetics showed that, in the absence of PEG, the antibody binds the hapten at the surface of lipid bilayers with the affinity of the soluble hapten. The incorporation of PEGylated lipids hinders antibody binding to extents depending on PEGylated lipid fraction and PEG molecular weight. SPR on immobilized liposomes thus appears as a useful technique to optimize formulations of liposomes for targeted therapy.

Fusion of raft-like lipid bilayers operated by a membranotropic domain of the HSV-type I glycoprotein gH occurs through a cholesterol-dependent mechanism

Soft Matter ◽  
2015 ◽  
Vol 11 (15) ◽  
pp. 3003-3016 ◽  
Author(s):  
Giuseppe Vitiello ◽  
Annarita Falanga ◽  
Ariel Alcides Petruk ◽  
Antonello Merlino ◽  
Giovanna Fragneto ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Lipid Raft ◽  
Type I ◽  
Specific Interactions ◽  
Dependent Mechanism

Specific interactions between cholesterol and the gH625 peptide are able to drive lipid re-arrangement resulting in lipid raft fusion.

scholarly journals Protein interaction patterns in different cellular environments are revealed by in-cell NMR

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Letizia Barbieri ◽  
Enrico Luchinat ◽  
Lucia Banci
Keyword(s):  
Soluble Proteins ◽  
Signal Recovery ◽  
Test Case ◽  
Biological Macromolecules ◽  
Specific Interactions ◽  
Bacterial Cells ◽  
Interaction Patterns ◽  
Relative Contribution ◽  
Cellular Environment ◽  
Nmr Signals

Abstract In-cell NMR allows obtaining atomic-level information on biological macromolecules in their physiological environment. Soluble proteins may interact with the cellular environment in different ways: either specifically, with their functional partners, or non-specifically, with other cellular components. Such behaviour often causes the disappearance of the NMR signals. Here we show that by introducing mutations on the human protein profilin 1, used here as a test case, the in-cell NMR signals can be recovered. In human cells both specific and non-specific interactions are present, while in bacterial cells only the effect of non-specific interactions is observed. By comparing the NMR signal recovery pattern in human and bacterial cells, the relative contribution of each type of interaction can be assessed. This strategy allows detecting solution in-cell NMR spectra of soluble proteins without altering their fold, thus extending the applicability of in-cell NMR to a wider range of proteins.

scholarly journals Hydrogen Bond Networks Near Supported Lipid Bilayers from Vibrational Sum Frequency Generation Experiments and Atomistic Simulations

2018 ◽  
Author(s):  
Merve Dogangun ◽  
Paul E. Ohno ◽  
Dongyue Liang ◽  
Alicia C. McGeachy ◽  
Ariana Gray Be ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Lipid Bilayers ◽  
Sum Frequency Generation ◽  
Atomistic Simulations ◽  
Supported Lipid Bilayers ◽  
Water Molecules ◽  
Specific Interactions ◽  
Sum Frequency ◽  
Hydrogen Bond Networks ◽  
Frequency Generation

<div> <div> <div> <p>We report vibrational sum frequency generation (SFG) spectra in which the C–H stretches of lipid alkyl tails in fully hydrogenated single- and dual-component supported lipid bilayers are detected along with the O–H stretching continuum above the bilayer. As the salt concentration is increased from ~10 μM to 0.1 M, the SFG intensities in the O–H stretching region decrease by a factor of 2, consistent with significant absorptive-dispersive mixing between χ(2) and χ(3) contributions to the SFG signal generation process from charged interfaces. A method for estimating the surface potential from the second-order spectral lineshapes (in the OH stretching region) is presented and discussed in the context of choosing truly zero-potential reference states. Aided by atomistic simulations, we find that the strength and orientation distribution of the hydrogen bonds over the purely zwitterionic bilayers are largely invariant between sub-micromolar and hundreds of millimolar concentrations. However, specific interactions between water molecules and lipid headgroups are observed upon replacing phosphocholine (PC) lipids with negatively charged phosphoglycerol (PG) lipids, which coincides with SFG signal intensity reductions in the 3100 cm-1 to 3200 cm-1 frequency region. The atomistic simulations show that this outcome is consistent with a small, albeit statistically significant, decrease in the number of water molecules adjacent to both the lipid phosphate and choline moieties per unit area, supporting the SFG observations. Ultimately, the ability to probe hydrogen-bond networks over lipid bilayers holds the promise of opening paths for understanding, controlling, and predicting specific and non-specific interactions between membranes and ions, small molecules, peptides, polycations, proteins, and coated and uncoated nanomaterials. Pre-edited version, 14 pages main text, 5 Figures, 1 Table, 29 pages Supporting Information available upon request.</p></div></div></div>

Observation of Concanavalin-A receptors on hydrated planar erythrocyte membrane film by in situ electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 608-609
Author(s):  
Neng-Bo He ◽  
S.W. Hui
Keyword(s):  
Lipid Bilayers ◽  
Erythrocyte Membrane ◽  
Lipid Membranes ◽  
Surface Film ◽  
Biological Membranes ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Black Lipid Membranes ◽  
Fine Mesh ◽  
Planar Films

Monolayers and planar "black" lipid membranes have been widely used as models for studying the structure and properties of biological membranes. Because of the lack of a suitable method to prepare these membranes for electron microscopic observation, their ultrastructure is so far not well understood. A method of forming molecular bilayers over the holes of fine mesh grids was developed by Hui et al. to study hydrated and unsupported lipid bilayers by electron diffraction, and to image phase separated domains by diffraction contrast. We now adapted the method of Pattus et al. of spreading biological membranes vesicles on the air-water interfaces to reconstitute biological membranes into unsupported planar films for electron microscopic study. hemoglobin-free human erythrocyte membrane stroma was prepared by hemolysis. The membranes were spreaded at 20°C on balanced salt solution in a Langmuir trough until a surface pressure of 20 dyne/cm was reached. The surface film was repeatedly washed by passing to adjacent troughs over shallow partitions (fig. 1).

Effect of Integral Proteins on Frozen Membrane Fracture

1980 ◽  
Vol 38 ◽  
pp. 756-759 ◽  
Author(s):  
S. Kirchanski ◽  
D. Branton
Keyword(s):  
Lipid Bilayers ◽  
Freeze Fracture ◽  
Covalent Bond ◽  
Erythrocyte Membranes ◽  
Glycophorin A ◽  
Experimental Protocol ◽  
Transmembrane Glycoprotein ◽  
Bond Breakage ◽  
Human Erythrocyte Membranes ◽  
Integral Proteins

We have investigated the effect of integral membrane proteins upon the fracturing of frozen lipid bilayers. This investigation has been part of an effort to develop freeze fracture labeling techniques and to assess the possible breakage of covalent protein bonds during the freeze fracture process. We have developed an experimental protocol utilizing lectin affinity columns which should detect small amounts of covalent bond breakage during the fracture of liposomes containing purified (1) glycophorin (a transmembrane glycoprotein of human erythrocyte membranes). To fracture liposomes in bulk, frozen liposomes are ground repeatedly under liquid nitrogen. Failure to detect any significant covalent bond breakage (contrary to (2)) led us to question the effectiveness of our grinding procedure in fracturing and splitting lipid bilayers.

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