scholarly journals Investigation of Fusion between Nanosized Lipid Vesicles and a Lipid Monolayer Toward Formation of Giant Lipid Vesicles with Various Kinds of Biomolecules

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 133
Author(s):  
Koki Kamiya ◽  
Chika Arisaka ◽  
Masato Suzuki
Keyword(s):  
Lipid Droplets ◽  
Lipid Membrane ◽  
Lipid Vesicles ◽  
Cationic Lipids ◽  
Lipid Monolayer ◽  
Fusion Method ◽  
Flip Flop ◽  
Artificial Cell ◽  
Large Unilamellar Vesicles ◽  
Anionic Lipids

We determined the properties of fusion between large unilamellar vesicles (LUVs) and the lipid monolayer by measuring the fluorescence intensity of rhodamine-conjugated phospholipids in cell-sized lipid vesicles. The charge of LUVs (containing cationic lipids) and lipid droplets (containing anionic lipids) promoted lipid membrane fusion. We also investigated the formation of cell-sized lipid vesicles with asymmetric lipid distribution using this fusion method. Moreover, cell-sized asymmetric ganglioside vesicles can be generated from the planar lipid bilayer formed at the interface between the lipid droplets with/without LUVs containing ganglioside. The flip-flop dynamics of ganglioside were observed on the asymmetric ganglioside vesicles. This fusion method can be used to form asymmetric lipid vesicles with poor solubility in n-decane or lipid vesicles containing various types of membrane proteins for the development of complex artificial cell models.

Biophysics (and sociology) of ceramides.

2005 ◽  
Vol 72 ◽  
pp. 177-188 ◽  
Author(s):  
Félix M. Goñi ◽  
F-Xabier Contreras ◽  
L-Ruth Montes ◽  
Jesús Sot ◽  
Alicia Alonso
Keyword(s):  
Cell Biology ◽  
Positive Curvature ◽  
Acyl Chain ◽  
Cell Signalling ◽  
Hexagonal Structure ◽  
Lipid Monolayer ◽  
Flip Flop ◽  
Long Chain ◽  
Bilayer Permeability

In the past decade, the long-neglected ceramides (N-acylsphingosines) have become one of the most attractive lipid molecules in molecular cell biology, because of their involvement in essential structures (stratum corneum) and processes (cell signalling). Most natural ceramides have a long (16-24 C atoms) N-acyl chain, but short N-acyl chain ceramides (two to six C atoms) also exist in Nature, apart from being extensively used in experimentation, because they can be dispersed easily in water. Long-chain ceramides are among the most hydrophobic molecules in Nature, they are totally insoluble in water and they hardly mix with phospholipids in membranes, giving rise to ceramide-enriched domains. In situ enzymic generation, or external addition, of long-chain ceramides in membranes has at least three important effects: (i) the lipid monolayer tendency to adopt a negative curvature, e.g. through a transition to an inverted hexagonal structure, is increased, (ii) bilayer permeability to aqueous solutes is notoriously enhanced, and (iii) transbilayer (flip-flop) lipid motion is promoted. Short-chain ceramides mix much better with phospholipids, promote a positive curvature in lipid monolayers, and their capacities to increase bilayer permeability or transbilayer motion are very low or non-existent.

scholarly journals The Impact of O-Glycosylation on Cyanidin Interaction with POPC Membranes: Structure-Activity Relationship

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2771
Author(s):  
Sylwia Cyboran-Mikołajczyk ◽  
Piotr Jurkiewicz ◽  
Martin Hof ◽  
Halina Kleszczyńska
Keyword(s):  
Biological Activity ◽  
Free Radicals ◽  
Lipid Bilayer ◽  
Lipid Membrane ◽  
Lipid Vesicles ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Beneficial Effects ◽  
Structure Activity ◽  
The Impact

Cyanidin and its O-glycosides have many important physiological functions in plants and beneficial effects on human health. Their biological activity is not entirely clear and depends on the structure of the molecule, in particular, on the number and type of sugar substituents. Therefore, in this study the detailed structure-activity relationship (SARs) of the anthocyanins/anthocyanidins in relation to their interactions with lipid bilayer was determined. On the basis of their antioxidant activity and the changes induced by them in size and Zeta potential of lipid vesicles, and mobility and order of lipid acyl chains, the impact of the number and type of sugar substituents on the biological activity of the compounds was evaluated. The obtained results have shown, that 3-O-glycosylation changes the interaction of cyanidin with lipid bilayer entirely. The 3-O-glycosides containing a monosaccharide induces greater changes in physical properties of the lipid membrane than those containing disaccharides. The presence of additional sugar significantly reduces glycoside interaction with model lipid membrane. Furthermore, O-glycosylation alters the ability of cyanidin to scavenge free radicals. This alteration depends on the type of free radicals and the sensitivity of the method used for their determination.

scholarly journals The interplay between lipids and dopamine on α-synuclein oligomerization and membrane binding

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Chi L. L. Pham ◽  
Roberto Cappai
Keyword(s):  
Lipid Membranes ◽  
Amyloid Fibrils ◽  
Lipid Membrane ◽  
Hydrophobic Interactions ◽  
Membrane Integrity ◽  
Lipid Vesicles ◽  
Helical Conformation ◽  
Unfolded Protein ◽  
Natively Unfolded Protein ◽  
Natively Unfolded

The deposition of α-syn (α-synuclein) as amyloid fibrils and the selective loss of DA (dopamine) containing neurons in the substantia nigra are two key features of PD (Parkinson's disease). α-syn is a natively unfolded protein and adopts an α-helical conformation upon binding to lipid membrane. Oligomeric species of α-syn have been proposed to be the pathogenic species associated with PD because they can bind lipid membranes and disrupt membrane integrity. DA is readily oxidized to generate reactive intermediates and ROS (reactive oxygen species) and in the presence of DA, α-syn form of SDS-resistant soluble oligomers. It is postulated that the formation of the α-syn:DA oligomers involves the cross-linking of DA-melanin with α-syn, via covalent linkage, hydrogen and hydrophobic interactions. We investigate the effect of lipids on DA-induced α-syn oligomerization and studied the ability of α-syn:DA oligomers to interact with lipids vesicles. Our results show that the interaction of α-syn with lipids inhibits the formation of DA-induced α-syn oligomers. Moreover, the α-syn:DA oligomer cannot interact with lipid vesicles or cause membrane permeability. Thus, the formation of α-syn:DA oligomers may alter the actions of α-syn which require membrane association, leading to disruption of its normal cellular function.

scholarly journals Size matters: Size Dependency of Gold Nanoparticles Interacting with Model Membranes

2019 ◽  
Author(s):  
Claudia Contini ◽  
James W. Hindley ◽  
Tom Macdonald ◽  
Joseph Barritt ◽  
Oscar Ces ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Lipid Bilayers ◽  
Lipid Membrane ◽  
Rapid Development ◽  
Membrane System ◽  
Size Dependent ◽  
Research Fields ◽  
Large Unilamellar Vesicles ◽  
Wide Range ◽  
Experimental Characterisation

<p><b>The rapid development of nanomaterials has led to an increase in the number and variety of engineered nanomaterials (ENMs) in the environment. Gold nanoparticles (AuNPs) are an example of a commonly studied ENM whose highly tailorable properties have generated significant interest through a wide range of research fields. In the present work, we report the first qualitative as well as quantitative experimental characterisation of the AuNP-membrane interaction. We investigate the interactions between citrate-stabilised AuNPs (diameters 5, 10, 25, 35, 50, 60 nm) and large unilamellar vesicles (LUVs) acting as a model membrane system. LUVs were prepared in two different formulations using 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) and 1,2-dileoyl-sn-glycero-3-phosphocholine (DOPC). Our results show that the interaction between AuNPs and LUVs is size dependent; in particular, we reveal the existence of two AuNP’s critical diameters which determine the fate of AuNPs in contact with a lipid membrane. The results provide a new understanding of the size dependent interaction between AuNPs and lipid bilayers of direct relevance to nanotoxicology and to the design of NP vectors.</b></p>

Relationship between water permeation and flip-flop motion in a bilayer membrane

2018 ◽  
Vol 20 (44) ◽  
pp. 28155-28161 ◽  
Author(s):  
Takuya Inokuchi ◽  
Noriyoshi Arai
Keyword(s):  
Lipid Membrane ◽  
Bilayer Membrane ◽  
Flip Flop ◽  
Water Permeation

We have investigated the effect of the flip-flop motion on the water permeation into the lipid membrane.

scholarly journals Gramicidin Increases Lipid Flip-Flop in Symmetric and Asymmetric Lipid Vesicles

2019 ◽  
Vol 116 (5) ◽  
pp. 860-873 ◽  
Author(s):  
Milka Doktorova ◽  
Frederick A. Heberle ◽  
Drew Marquardt ◽  
Radda Rusinova ◽  
R. Lea Sanford ◽  
...  
Keyword(s):  
Lipid Vesicles ◽  
Flip Flop

scholarly journals Highly oriented photosynthetic reaction centers generate a proton gradient in synthetic protocells

2017 ◽  
Vol 114 (15) ◽  
pp. 3837-3842 ◽  
Author(s):  
Emiliano Altamura ◽  
Francesco Milano ◽  
Roberto R. Tangorra ◽  
Massimo Trotta ◽  
Omar Hassan Omar ◽  
...  
Keyword(s):  
Reaction Center ◽  
Lipid Membrane ◽  
Transmembrane Protein ◽  
Photosynthetic Reaction Center ◽  
Lipid Vesicles ◽  
Reaction Centers ◽  
Proton Gradient ◽  
Continuous Illumination ◽  
Photosynthetic Reaction Centers ◽  
Transfer Method

Photosynthesis is responsible for the photochemical conversion of light into the chemical energy that fuels the planet Earth. The photochemical core of this process in all photosynthetic organisms is a transmembrane protein called the reaction center. In purple photosynthetic bacteria a simple version of this photoenzyme catalyzes the reduction of a quinone molecule, accompanied by the uptake of two protons from the cytoplasm. This results in the establishment of a proton concentration gradient across the lipid membrane, which can be ultimately harnessed to synthesize ATP. Herein we show that synthetic protocells, based on giant lipid vesicles embedding an oriented population of reaction centers, are capable of generating a photoinduced proton gradient across the membrane. Under continuous illumination, the protocells generate a gradient of 0.061 pH units per min, equivalent to a proton motive force of 3.6 mV⋅min−1. Remarkably, the facile reconstitution of the photosynthetic reaction center in the artificial lipid membrane, obtained by the droplet transfer method, paves the way for the construction of novel and more functional protocells for synthetic biology.

scholarly journals A Unique Junctional Interface at Contact Sites Between the Endoplasmic Reticulum and Lipid Droplets

2021 ◽  
Vol 9 ◽  
Author(s):  
Vineet Choudhary ◽  
Roger Schneiter
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Droplets ◽  
Neutral Lipids ◽  
Close Contact ◽  
Lipid Storage ◽  
Metabolic Energy ◽  
Lipid Monolayer ◽  
Storage Diseases ◽  
Contact Sites ◽  
Ordered Assembly

Lipid droplets (LDs) constitute compartments dedicated to the storage of metabolic energy in the form of neutral lipids. LDs originate from the endoplasmic reticulum (ER) with which they maintain close contact throughout their life cycle. These ER–LD junctions facilitate the exchange of both proteins and lipids between these two compartments. In recent years, proteins that are important for the proper formation of LDs and localize to ER–LD junctions have been identified. This junction is unique as it is generally believed to invoke a transition from the ER bilayer membrane to a lipid monolayer that delineates LDs. Proper formation of this junction requires the ordered assembly of proteins and lipids at specialized ER subdomains. Without such a well-ordered assembly of LD biogenesis factors, neutral lipids are synthesized throughout the ER membrane, resulting in the formation of aberrant LDs. Such ectopically formed LDs impact ER and lipid homeostasis, resulting in different types of lipid storage diseases. In response to starvation, the ER–LD junction recruits factors that tether the vacuole to these junctions to facilitate LD degradation. In addition, LDs maintain close contacts with peroxisomes and mitochondria for metabolic channeling of the released fatty acids toward beta-oxidation. In this review, we discuss the function of different components that ensure proper functioning of LD contact sites, their role in lipogenesis and lipolysis, and their relation to lipid storage diseases.

scholarly journals Multivalent lipid targeting by the calcium-independent C2A domain of Slp-4/granuphilin

2020 ◽  
Author(s):  
Aml A Alnaas ◽  
Abena Watson-Siriboe ◽  
Sherleen Tran ◽  
Mikias Negussie ◽  
Jack A. Henderson ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Lipid Vesicles ◽  
Lipid Binding ◽  
Snare Complex ◽  
Rab Proteins ◽  
Secretory Vesicles ◽  
High Affinity ◽  
Anionic Lipids ◽  
Dynamics Simulations ◽  
C2a Domain

ABSTRACTSynaptotagmin-like protein 4 (Slp-4), also known as granuphilin, is a Rab effector responsible for docking secretory vesicles to the plasma membrane before exocytosis. Slp-4 binds vesicular Rab proteins via an N-terminal Slp homology (SHD) domain, interacts with plasma membrane SNARE complex proteins via a central linker region, and contains tandem C-terminal C2 domains (C2A and C2B) with affinity for phosphatidylinositol-(4,5)-bisphosphate (PIP2). The Slp-4 C2A domain binds with low nanomolar apparent affinity to PIP2 in lipid vesicles that also contain background anionic lipids such as phosphatidylserine (PS), but much weaker when either the background anionic lipids or PIP2 are removed. Through computational and experimental approaches, we show that this high affinity membrane interaction arises from concerted interaction at multiple sites on the C2A domain. In addition to a conserved PIP2-selective lysine cluster, there exists a larger cationic surface surrounding the cluster which contributes substantially to the affinity for physiologically relevant lipid compositions. While mutations at the PIP2-selective site decrease affinity for PIP2, multiple mutations are needed to decrease binding to physiologically relevant lipid compositions. Docking and molecular dynamics simulations indicate several conformationally flexible loops that contribute to the nonspecific cationic surface. We also identify and characterize a covalently modified variant in the bacterially expressed protein, which arises through reactivity of the PIP2-binding lysine cluster with endogenous bacterial compounds and has a low membrane affinity. Overall, multivalent lipid binding by the Slp-4 C2A domain provides selective recognition and high affinity docking of large dense-core secretory vesicles to the plasma membrane.

scholarly journals Correlative microscopy reveals the nanoscale morphology of E. coli-derived supported lipid bilayers

2021 ◽  
Author(s):  
Karan Bali ◽  
Zeinab Mohamed ◽  
Anna-Maria Pappa ◽  
Susan Daniel ◽  
Clemens F. Kaminski ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membrane ◽  
Lipid Vesicles ◽  
Outer Membrane Vesicles ◽  
Atomic Scale ◽  
Membrane Properties ◽  
Supported Lipid Bilayers ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Natural And Synthetic

Supported lipid bilayers (SLBs) made from reconstituted lipid vesicles are an important tool in molecular biology. A breakthrough in the field has come with the use of vesicles derived from cell membranes to form SLBs. These new supported bilayers, consisting both of natural and synthetic components, provide a physiologically relevant system on which to study protein-protein interactions as well as protein-ligand interactions and other lipid membrane properties. These complex bilayer systems hold promise but have not yet been fully characterised in terms of their composition, ratio of natural to synthetic component and membrane protein content. Here, we describe a method of correlative atomic force (AFM) with structured illumination microscopy (SIM) for the accurate mapping of complex lipid bilayers that consist of a synthetic fraction and a fraction of lipids derived from Escherichia coli outer membrane vesicles (OMVs). We exploit the enhanced resolution and molecular specificity that SIM can offer to identify areas of interest in these bilayers and the atomic scale resolution that the AFM provides to create detailed topography maps of the bilayers. We are thus able to understand the way in which the two different lipid fractions (natural and synthetic) mix within the bilayers, quantify the amount of bacterial membrane incorporated in the bilayer and directly visualise the interaction of these bilayers with bacteria-specific, membrane-binding proteins. Our work sets the foundation for accurately understanding the composition and properties of OMV-derived SLBs and establishes correlative AFM/ SIM as a method for characterising complex systems at the nanoscale.

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