scholarly journals Lipid bilayer degradation induced by SARS-CoV-2 spike protein as revealed by neutron reflectometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alessandra Luchini ◽  
Samantha Micciulla ◽  
Giacomo Corucci ◽  
Krishna Chaithanya Batchu ◽  
Andreas Santamaria ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Membrane Lipids ◽  
Lipid Extraction ◽  
Specific Interaction ◽  
Structural Features ◽  
Supported Lipid Bilayers ◽  
Fusion Event ◽  
Angiotensin Converting Enzyme 2 ◽  
Neutron Reflection

AbstractSARS-CoV-2 spike proteins are responsible for the membrane fusion event, which allows the virus to enter the host cell and cause infection. This process starts with the binding of the spike extramembrane domain to the angiotensin-converting enzyme 2 (ACE2), a membrane receptor highly abundant in the lungs. In this study, the extramembrane domain of SARS-CoV-2 Spike (sSpike) was injected on model membranes formed by supported lipid bilayers in presence and absence of the soluble part of receptor ACE2 (sACE2), and the structural features were studied at sub-nanometer level by neutron reflection. In all cases the presence of the protein produced a remarkable degradation of the lipid bilayer. Indeed, both for membranes from synthetic and natural lipids, a significant reduction of the surface coverage was observed. Quartz crystal microbalance measurements showed that lipid extraction starts immediately after sSpike protein injection. All measurements indicate that the presence of proteins induces the removal of membrane lipids, both in the presence and in the absence of ACE2, suggesting that sSpike molecules strongly associate with lipids, and strip them away from the bilayer, via a non-specific interaction. A cooperative effect of sACE2 and sSpike on lipid extraction was also observed.

scholarly journals Lipid Bilayer Degradation Induced by SARS-CoV-2 Spike Protein as Revealed by Neutron Reflectometry

2021 ◽  
Author(s):  
Alessandra Luchini ◽  
Samantha Micciulla ◽  
Giacomo Corucci ◽  
Krishna Chaithanya Batchu ◽  
Andreas Santamaria ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Membrane Lipids ◽  
Lipid Extraction ◽  
Specific Interaction ◽  
Structural Features ◽  
Supported Lipid Bilayers ◽  
Fusion Event ◽  
Angiotensin Converting Enzyme 2 ◽  
Neutron Reflection

Abstract SARS-CoV-2 spike proteins are responsible for the membrane fusion event, which allows the virus to enter the host cell and cause infection. This process starts with the binding of the spike extramembrane domain to the angiotensin-converting enzyme 2 (ACE2), a membrane receptor highly abundant in the lungs. In this study, the extramembrane domain of SARS-CoV-2 Spike (sSpike) was injected on model membranes, formed by supported lipid bilayers in presence and absence of the soluble part of receptor ACE2 (sACE2), and the structural features were studied at sub-nanometer level by neutron reflection. In all cases the presence of the protein produced a remarkable degradation of the lipid bilayer. Indeed, both for membranes from synthetic and natural lipids, a significant reduction of the surface coverage was observed. Quartz crystal microbalance measurements show that lipid extraction starts immediately after sSpike protein injection. All measurements indicate that the presence of proteins induces the removal of membrane lipids, both in the presence and in the absence of ACE2, suggesting that sSpike molecules strongly associate with lipids, and strip them away from the bilayer, via a non-specific interaction. A cooperative effect of sACE2 and sSpike on lipid extraction was also observed.

scholarly journals Monitoring supported lipid bilayers with n-type organic electrochemical transistors

2020 ◽  
Vol 7 (9) ◽  
pp. 2348-2358 ◽  
Author(s):  
Malak Kawan ◽  
Tania C. Hidalgo ◽  
Weiyuan Du ◽  
Anna-Maria Pappa ◽  
Róisín M. Owens ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Supported Lipid Bilayers ◽  
Accumulation Mode ◽  
Electrochemical Transistor ◽  
Organic Electrochemical Transistors

An n-type, accumulation mode, microscale organic electrochemical transistor monitors the activity of a pore-forming protein integrated into a lipid bilayer.

scholarly journals Transport efficiency of membrane-anchored kinesin-1 motors depends on motor density and diffusivity

2016 ◽  
Vol 113 (46) ◽  
pp. E7185-E7193 ◽  
Author(s):  
Rahul Grover ◽  
Janine Fischer ◽  
Friedrich W. Schwarz ◽  
Wilhelm J. Walter ◽  
Petra Schwille ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Single Molecule ◽  
Gliding Motility ◽  
Supported Lipid Bilayers ◽  
Transport Efficiency ◽  
Collective Transport ◽  
Wide Range ◽  
Motor Density

In eukaryotic cells, membranous vesicles and organelles are transported by ensembles of motor proteins. These motors, such as kinesin-1, have been well characterized in vitro as single molecules or as ensembles rigidly attached to nonbiological substrates. However, the collective transport by membrane-anchored motors, that is, motors attached to a fluid lipid bilayer, is poorly understood. Here, we investigate the influence of motors’ anchorage to a lipid bilayer on the collective transport characteristics. We reconstituted “membrane-anchored” gliding motility assays using truncated kinesin-1 motors with a streptavidin-binding peptide tag that can attach to streptavidin-loaded, supported lipid bilayers. We found that the diffusing kinesin-1 motors propelled the microtubules in the presence of ATP. Notably, we found the gliding velocity of the microtubules to be strongly dependent on the number of motors and their diffusivity in the lipid bilayer. The microtubule gliding velocity increased with increasing motor density and membrane viscosity, reaching up to the stepping velocity of single motors. This finding is in contrast to conventional gliding motility assays where the density of surface-immobilized kinesin-1 motors does not influence the microtubule velocity over a wide range. We reason that the transport efficiency of membrane-anchored motors is reduced because of their slippage in the lipid bilayer, an effect that we directly observed using single-molecule fluorescence microscopy. Our results illustrate the importance of motor–cargo coupling, which potentially provides cells with an additional means of regulating the efficiency of cargo transport.

Interfacial Behaviors of Transmembrane Peptides in Lipid Bilayer Studied by X-Ray and Neutron Reflectivity

2020 ◽  
Vol 977 ◽  
pp. 184-189
Author(s):  
Dong Jin Choi ◽  
Zeeshan Ur Rehman
Keyword(s):  
Membrane Proteins ◽  
Lipid Bilayers ◽  
Lipid Membrane ◽  
Membrane Lipids ◽  
Solid Substrate ◽  
Neutron Reflectivity ◽  
Transmembrane Peptides ◽  
X Ray ◽  
Neutron Reflection ◽  
Membrane Spanning

Lipids and proteins can influence each other in so many different ways. Lipids may affect the structure of membrane proteins by influencing their backbone conformation, the tilt, rotation angles of their transmembrane (TM) segments, and the orientation of their side chains. The membrane-spanning parts in integral membrane proteins are predominantly hydrophobic, and most often helical. At the lipid-protein interface, the TM part of the protein and the hydrocarbon chains of the lipid molecules have to coexist to maintain the integrity of the membrane. Lipids are important components of lipid membrane are used in various experiments reported in this thesis and can act as model lipid bilayers. Once they support on solid substrate like silicon wafers, their structural properties can investigate by X-ray and neutron reflectivity and by other useful techniques. Reflectivity technique can provide detailed information such as their thickness and interaction between lipids and peptides. The thesis reports a detailed investigation of these lipids and peptides by X-ray and neutron reflection techniques

Supported lipid bilayer repair mediated by AH peptide

2016 ◽  
Vol 18 (4) ◽  
pp. 3040-3047 ◽  
Author(s):  
Min Chul Kim ◽  
Anders Gunnarsson ◽  
Seyed R. Tabaei ◽  
Fredrik Höök ◽  
Nam-Joon Cho
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Silicon Oxide ◽  
Supported Lipid Bilayers ◽  
High Quality ◽  
Supported Lipid Bilayer

High quality and complete supported lipid bilayers are formed on silicon oxide by employing an AH peptide mediated repair step.

scholarly journals Membrane Interactivity of Anesthetic Adjuvant Dexmedetomidine Discriminable from Clonidine and Enantiomeric Levomedetomidine

2019 ◽  
pp. 1-15
Author(s):  
Maki Mizogami ◽  
Hironori Tsuchiya
Keyword(s):  
Membrane Fluidity ◽  
Lipid Rafts ◽  
Lipid Bilayers ◽  
Nerve Cell ◽  
Adrenergic Receptors ◽  
Membrane Lipids ◽  
Specific Interaction ◽  
Hydroxyl Groups ◽  
Clinical Effects ◽  
Adrenergic Agonists

Aims: Dexmedetomidine, which has been increasingly used as an anesthetic adjuvant, is more lipophilic and more active than another α2-adrenergic agonist clonidine and enantiomeric levomedetomidine. Lipophilicity and stereostructure affect the clinical effects of α2-adrenergic agonists. We aimed to compare the membrane interactivity of dexmedetomidine with clonidine and levomedetomidine from a point of view different from the mode of action on α2-adrenergic receptors. Methodology: Unilamellar vesicles were prepared with phospholipids and cholesterol to mimic the lipid compositions of peripheral nerve cell, central nerve cell and cardiomyocyte membranes, and lipid rafts. They were subjected to the reactions with dexmedetomidine, clonidine and levomedetomidine at 10-200 μM, followed by measuring fluorescence polarization to determine the membrane interactivity to change membrane fluidity and specify the membrane region for the stereostructure-specific interaction. Results: Dexmedetomidine and clonidine acted on lipid bilayers to increase the membrane fluidity with potencies varying by a compositional difference of membrane lipids. Dexmedetomidine showed greater interactivity with neuro-mimetic and cardiomyocyte-mimetic membranes than clonidine, being consistent with their comparative lipophilicity and activity. The effects of α2-adrenergic agonists on lipid raft model membranes were much weaker than those on other membranes, indicating that lipid rafts are not mechanistically relevant to them. Higher interactive dexmedetomidine was discriminated from lower interactive levomedetomidine in the presence of chiral cholesterol in membranes. An interactivity difference between two enantiomers was largest in the superficial region of lipid bilayers and the rank order of their membrane-interacting potency was reversed by replacing cholesterol with epicholesterol, suggesting that cholesterol’s 3β-hydroxyl groups positioned close to the membrane surface are responsible for the enantioselective interaction. Conclusion: Dexmedetomidine structure-specifically interacts with biomimetic membranes depending on their lipid compositions more potently than clonidine and levomedetomidine. Such membrane interactivity associated with higher lipophilicity and stereostructure characterizes dexmedetomidine in addition to higher affinity for α2-adrenergic receptors.

scholarly journals Transport efficiency of membrane-anchored kinesin-1 motors depends on motor density and diffusivity

2016 ◽  
Author(s):  
Rahul Grover ◽  
Janine Fischer ◽  
Friedrich W. Schwarz ◽  
Wilhelm J. Walter ◽  
Petra Schwille ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Gliding Motility ◽  
Supported Lipid Bilayers ◽  
Transport Efficiency ◽  
Collective Transport ◽  
Wide Range ◽  
Biological Substrates ◽  
Motor Density

AbstractIn eukaryotic cells, membranous vesicles and organelles are transported by ensembles of motor proteins. These motors, such as kinesin-1, have been well characterized in vitro as single molecules or as ensembles rigidly attached to non-biological substrates. However, the collective transport by membrane-anchored motors, i.e. motors attached to a fluid lipid bilayer, is poorly understood. Here, we investigate the influence of motors anchorage to a lipid bilayer on the collective transport characteristics. We reconstituted ‘membrane-anchored’ gliding motility assays using truncated kinesin-1 motors with a streptavidin-binding-peptide tag that can attach to streptavidin-loaded, supported lipid bilayers. We found that the diffusing kinesin-1 motors propelled the microtubules in presence of ATP. Notably, we found the gliding velocity of the microtubules to be strongly dependent on the number of motors and their diffusivity in the lipid bilayer. The microtubule gliding velocity increased with increasing motor density and membrane viscosity, reaching up to the stepping velocity of single-motors. This finding is in contrast to conventional gliding motility assays where the density of surface-immobilized kinesin-1 motors does not influence the microtubule velocity over a wide range. We reason, that the transport efficiency of membrane-anchored motors is reduced because of their slippage in the lipid bilayer, an effect which we directly observed using singlemolecule fluorescence microscopy. Our results illustrate the importance of the motor-cargo coupling, which potentially provides cells with an additional means of regulating the efficiency of cargo transport.

scholarly journals Urea-mediated anomalous diffusion in supported lipid bilayers

2018 ◽  
Vol 8 (5) ◽  
pp. 20180028 ◽  
Author(s):  
E. E. Weatherill ◽  
H. L. E. Coker ◽  
M. R. Cheetham ◽  
M. I. Wallace
Keyword(s):  
Brownian Motion ◽  
Polyethylene Glycol ◽  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Anomalous Diffusion ◽  
Incubation Time ◽  
Time Scale ◽  
Biological Membranes ◽  
Model Systems ◽  
Supported Lipid Bilayers

Diffusion in biological membranes is seldom simply Brownian motion; instead, the rate of diffusion is dependent on the time scale of observation and so is often described as anomalous. In order to help better understand this phenomenon, model systems are needed where the anomalous diffusion of the lipid bilayer can be tuned and quantified. We recently demonstrated one such model by controlling the excluded area fraction in supported lipid bilayers (SLBs) through the incorporation of lipids derivatized with polyethylene glycol. Here, we extend this work, using urea to induce anomalous diffusion in SLBs. By tuning incubation time and urea concentration, we produce bilayers that exhibit anomalous behaviour on the same scale as that observed in biological membranes.

Microcavity array supported lipid bilayer models of ganglioside – influenza hemagglutinin1 binding

2020 ◽  
Vol 56 (76) ◽  
pp. 11251-11254 ◽  
Author(s):  
Guilherme B. Berselli ◽  
Nirod Kumar Sarangi ◽  
Aurélien V. Gimenez ◽  
Paul V. Murphy ◽  
Tia E. Keyes
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Supported Lipid Bilayers ◽  
Supported Lipid Bilayer

The binding of influenza receptor (HA1) to membranes containing different glycosphingolipid receptors was investigated at Microcavity Supported Lipid Bilayers (MSLBs).

scholarly journals Nanoarchitectured air-stable supported lipid bilayer incorporating sucrose–bicelle complex system

2022 ◽  
Vol 9 (1) ◽  
Author(s):  
Hyunhyuk Tae ◽  
Soohyun Park ◽  
Gamaliel Junren Ma ◽  
Nam-Joon Cho
Keyword(s):  
Complex System ◽  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Supported Lipid Bilayers ◽  
Air Exposure ◽  
Supported Lipid Bilayer ◽  
Wide Range ◽  
Aqueous Environments ◽  
One Step ◽  
Self Assembled Layer

AbstractCell-membrane-mimicking supported lipid bilayers (SLBs) provide an ultrathin, self-assembled layer that forms on solid supports and can exhibit antifouling, signaling, and transport properties among various possible functions. While recent material innovations have increased the number of practically useful SLB fabrication methods, typical SLB platforms only work in aqueous environments and are prone to fluidity loss and lipid-bilayer collapse upon air exposure, which limits industrial applicability. To address this issue, herein, we developed sucrose–bicelle complex system to fabricate air-stable SLBs that were laterally mobile upon rehydration. SLBs were fabricated from bicelles in the presence of up to 40 wt% sucrose, which was verified by quartz crystal microbalance-dissipation (QCM-D) and fluorescence recovery after photobleaching (FRAP) experiments. The sucrose fraction in the system was an important factor; while 40 wt% sucrose induced lipid aggregation and defects on SLBs after the dehydration–rehydration process, 20 wt% sucrose yielded SLBs that exhibited fully recovered lateral mobility after these processes. Taken together, these findings demonstrate that sucrose–bicelle complex system can facilitate one-step fabrication of air-stable SLBs that can be useful for a wide range of biointerfacial science applications.

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