scholarly journals Correlated diffusion in lipid bilayers

2021 ◽  
Vol 118 (48) ◽  
pp. e2113202118
Author(s):  
Rafael L. Schoch ◽  
Frank L. H. Brown ◽  
Gilad Haran
Keyword(s):  
Lipid Bilayers ◽  
Single Molecule ◽  
Lipid Membranes ◽  
Supported Lipid Bilayers ◽  
Single Molecule Tracking ◽  
Black Lipid Membranes ◽  
Molecular Tracking ◽  
Physical Materials ◽  
Multiple Molecules ◽  
Major Target

Lipid membranes are complex quasi–two-dimensional fluids, whose importance in biology and unique physical/materials properties have made them a major target for biophysical research. Recent single-molecule tracking experiments in membranes have caused some controversy, calling the venerable Saffman–Delbrück model into question and suggesting that, perhaps, current understanding of membrane hydrodynamics is imperfect. However, single-molecule tracking is not well suited to resolving the details of hydrodynamic flows; observations involving correlations between multiple molecules are superior for this purpose. Here dual-color molecular tracking with submillisecond time resolution and submicron spatial resolution is employed to reveal correlations in the Brownian motion of pairs of fluorescently labeled lipids in membranes. These correlations extend hundreds of nanometers in freely floating bilayers (black lipid membranes) but are severely suppressed in supported lipid bilayers. The measurements are consistent with hydrodynamic predictions based on an extended Saffman–Delbrück theory that explicitly accounts for the two-leaflet bilayer structure of lipid membranes.

scholarly journals Non-vesicular transfer of membrane proteins from nanoparticles to lipid bilayers

2011 ◽  
Vol 137 (2) ◽  
pp. 217-223 ◽  
Author(s):  
Sourabh Banerjee ◽  
Crina M. Nimigean
Keyword(s):  
Membrane Proteins ◽  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Single Molecule ◽  
Lipid Membranes ◽  
Single Channel ◽  
Black Lipid Membranes ◽  
Potassium Channel Kcsa ◽  
Lipid Environment ◽  
Biochemical Preparation

Discoidal lipoproteins are a novel class of nanoparticles for studying membrane proteins (MPs) in a soluble, native lipid environment, using assays that have not been traditionally applied to transmembrane proteins. Here, we report the successful delivery of an ion channel from these particles, called nanoscale apolipoprotein-bound bilayers (NABBs), to a distinct, continuous lipid bilayer that will allow both ensemble assays, made possible by the soluble NABB platform, and single-molecule assays, to be performed from the same biochemical preparation. We optimized the incorporation and verified the homogeneity of NABBs containing a prototypical potassium channel, KcsA. We also evaluated the transfer of KcsA from the NABBs to lipid bilayers using single-channel electrophysiology and found that the functional properties of the channel remained intact. NABBs containing KcsA were stable, homogeneous, and able to spontaneously deliver the channel to black lipid membranes without measurably affecting the electrical properties of the bilayer. Our results are the first to demonstrate the transfer of a MP from NABBs to a different lipid bilayer without involving vesicle fusion.

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).

scholarly journals The Use of Tethered Bilayer Lipid Membranes to Identify the Mechanisms of Antimicrobial Peptide Interactions with Lipid Bilayers

Antibiotics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 12 ◽  
Author(s):  
Amani Alghalayini ◽  
Alvaro Garcia ◽  
Thomas Berry ◽  
Charles Cranfield
Keyword(s):  
New Zealand ◽  
Patch Clamp ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Antimicrobial Agents ◽  
Bilayer Lipid Membranes ◽  
Bilayer Lipid ◽  
Black Lipid Membranes ◽  
Peptide Interactions ◽  
New Research

This review identifies the ways in which tethered bilayer lipid membranes (tBLMs) can be used for the identification of the actions of antimicrobials against lipid bilayers. Much of the new research in this area has originated, or included researchers from, the southern hemisphere, Australia and New Zealand in particular. More and more, tBLMs are replacing liposome release assays, black lipid membranes and patch-clamp electrophysiological techniques because they use fewer reagents, are able to obtain results far more quickly and can provide a uniformity of responses with fewer artefacts. In this work, we describe how tBLM technology can and has been used to identify the actions of numerous antimicrobial agents.

The Effect of Weak Permanent Magnetic Fields on the Electric Properties of Lipid-Bilayers

1995 ◽  
Vol 50 (11-12) ◽  
pp. 833-839 ◽  
Author(s):  
Alexander Pazur
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Chlorophyll A ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Quantum Mechanical ◽  
Leakage Currents ◽  
Black Lipid Membranes ◽  
External Static Magnetic Field ◽  
Membrane Location

Abstract Black lipid membranes were prepared on a Teflon septum separating electrically the two chambers of a Teflon cuvette, using the technique of Mueller et al., (Nature 194. 979 (1962)). An external, static magnetic field was applied, whose intensity varied from 0 G to 100 G at the membrane location. Field applications higher than 10 G are effecting higher leakage currents, increased capacity and faster breakdown of the bilayer state, as compared to the absence of a magnetic field. If bilayers were doped with chlorophyll a, these effects were increased. Quantum mechanical and thermodynamical phenomena on membranes will be discussed as possible origins of these effects.

Single-Molecule Detection with Lightguiding Nanowires: Determination of Protein Concentration and Diffusivity in Supported Lipid Bilayers

Nano Letters ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 6182-6191 ◽  
Author(s):  
Damiano Verardo ◽  
Björn Agnarsson ◽  
Vladimir P. Zhdanov ◽  
Fredrik Höök ◽  
Heiner Linke
Keyword(s):  
Lipid Bilayers ◽  
Single Molecule ◽  
Protein Concentration ◽  
Single Molecule Detection ◽  
Supported Lipid Bilayers

Post-Hoc Vibration Mitigation for Single-Molecule Tracking and Diffusion Measurements in Lipid Membranes

2010 ◽  
Vol 43 (7-8) ◽  
pp. 586-596
Author(s):  
Derek J. Bailey ◽  
Jared T. Kindt ◽  
M. Madison Taylor ◽  
Ashley R. Paulson ◽  
Brynna H. Jones ◽  
...  
Keyword(s):  
Single Molecule ◽  
Lipid Membranes ◽  
Vibration Mitigation ◽  
Single Molecule Tracking ◽  
Post Hoc ◽  
And Diffusion

Single-Molecule Fluorescence Imaging of Peptide Binding to Supported Lipid Bilayers

2009 ◽  
Vol 81 (13) ◽  
pp. 5130-5138 ◽  
Author(s):  
Christopher B. Fox ◽  
Joshua R. Wayment ◽  
Grant A. Myers ◽  
Scott K. Endicott ◽  
Joel M. Harris
Keyword(s):  
Fluorescence Imaging ◽  
Lipid Bilayers ◽  
Single Molecule ◽  
Peptide Binding ◽  
Supported Lipid Bilayers ◽  
Single Molecule Fluorescence

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.

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