scholarly journals The membrane transporter lactose permease increases lipid bilayer bending rigidity

2021 ◽  
Author(s):  
Nestor Lopez Mora ◽  
Heather E. Findlay ◽  
Nicholas J. Brooks ◽  
Sowmya Purushothaman ◽  
Oscar Ces ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Lactose Permease ◽  
Membrane Transporter ◽  
Bending Rigidity

scholarly journals The lipid bilayer determines helical tilt angle and function in lactose permease of Escherichia coli

1997 ◽  
Vol 94 (19) ◽  
pp. 10167-10171 ◽  
Author(s):  
J. le Coutre ◽  
L. R. Narasimhan ◽  
C. K. N. Patel ◽  
H. R. Kaback
Keyword(s):  
Escherichia Coli ◽  
Lipid Bilayer ◽  
Tilt Angle ◽  
Lactose Permease ◽  
And Function

scholarly journals The Effect of the Osmotically Active Compound Concentration Difference on the Passive Water and Proton Fluxes across a Lipid Bilayer

2021 ◽  
Vol 22 (20) ◽  
pp. 11099
Author(s):  
Magdalena Przybyło ◽  
Dominik Drabik ◽  
Joanna Doskocz ◽  
Aleš Iglič ◽  
Marek Langner
Keyword(s):  
Lipid Bilayer ◽  
Water Flow ◽  
Active Compound ◽  
Pore Formation ◽  
Biological Significance ◽  
Bending Rigidity ◽  
Hydrophobic Membrane ◽  
Concentration Difference ◽  
Lipid Pore ◽  
Pore Opening

The molecular details of the passive water flux across the hydrophobic membrane interior are still a matter of debate. One of the postulated mechanisms is the spontaneous, water-filled pore opening, which facilitates the hydrophilic connection between aqueous phases separated by the membrane. In the paper, we provide experimental evidence showing that the spontaneous lipid pore formation correlates with the membrane mechanics; hence, it depends on the composition of the lipid bilayer and the concentration of the osmotically active compound. Using liposomes as an experimental membrane model, osmotically induced water efflux was measured with the stopped-flow technique. Shapes of kinetic curves obtained at low osmotic pressure differences are interpreted in terms of two events: the lipid pore opening and water flow across the aqueous channel. The biological significance of the dependence of the lipid pore formation on the concentration difference of an osmotically active compound was illustrated by the demonstration that osmotically driven water flow can be accompanied by the dissipation of the pH gradient. The application of the Helfrich model to describe the probability of lipid pore opening was validated by demonstrating that the probability of pore opening correlates with the membrane bending rigidity. The correlation was determined by experimentally derived bending rigidity coefficients and probabilities of lipid pores opening.

Coarse-grained simulation: a high-throughput computational approach to membrane proteins

2008 ◽  
Vol 36 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Mark S.P. Sansom ◽  
Kathryn A. Scott ◽  
Peter J. Bond
Keyword(s):  
Membrane Proteins ◽  
Lipid Bilayer ◽  
High Throughput ◽  
Protein Interactions ◽  
Coarse Grained ◽  
Atomistic Simulations ◽  
Lactose Permease ◽  
Coarse Grained Simulations ◽  
Dynamics Simulations ◽  
Good Agreement

An understanding of the interactions of membrane proteins with a lipid bilayer environment is central to relating their structure to their function and stability. A high-throughput approach to prediction of membrane protein interactions with a lipid bilayer based on coarse-grained Molecular Dynamics simulations is described. This method has been used to develop a database of CG simulations (coarse-grained simulations) of membrane proteins (http://sbcb.bioch.ox.ac.uk/cgdb). Comparison of CG simulations and AT simulations (atomistic simulations) of lactose permease reveals good agreement between the two methods in terms of predicted lipid headgroup contacts. Both CG and AT simulations predict considerable local bilayer deformation by the voltage sensor domain of the potassium channel KvAP.

scholarly journals Bending rigidity of charged lipid bilayer membranes

Soft Matter ◽  
2019 ◽  
Vol 15 (29) ◽  
pp. 6006-6013 ◽  
Author(s):  
Hammad A. Faizi ◽  
Shelli L. Frey ◽  
Jan Steinkühler ◽  
Rumiana Dimova ◽  
Petia M. Vlahovska
Keyword(s):  
Lipid Bilayer ◽  
Lipid Bilayer Membranes ◽  
Bending Rigidity ◽  
Bilayer Membranes

We experimentally study the increase of bending rigidity with charge content of bilayer membranes using GUVs made of a mixture of neutral and monovalent negatively charged lipids.

scholarly journals The Elucidation of the Molecular Mechanism of the Extrusion Process

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4278
Author(s):  
Joanna Doskocz ◽  
Paulina Dałek ◽  
Magdalena Przybyło ◽  
Barbara Trzebicka ◽  
Aleksander Foryś ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lipid Bilayer ◽  
Molecular Mechanisms ◽  
Flicker Noise ◽  
Extrusion Process ◽  
Extrusion Force ◽  
Bending Rigidity ◽  
Polycarbonate Membrane ◽  
Noise Spectroscopy ◽  
Liposome Suspension

Extrusion is a popular method for producing homogenous population of unilamellar liposomes. The technique relies on forcing a lipid suspension through cylindrical pores in a polycarbonate membrane. The quantification of the extrusion and/or recalibration processes make possible the acquisition of experimental data, which can be correlated with the mechanical properties of the lipid bilayer. In this work, the force needed for the extrusion process was correlated with the mechanical properties of a lipid bilayer derived from other experiments. Measurements were performed using a home-made dedicated device capable of maintaining a stable volumetric flux of a liposome suspension through well-defined pores and to continuously measure the extrusion force. Based on the obtained results, the correlation between the lipid bilayer bending rigidity and extrusion force was derived. Specifically, it was found that the bending rigidity of liposomes formed from well-defined lipid mixtures agrees with data obtained by others using flicker-noise spectroscopy or micromanipulation. The other issue addressed in the presented studies was the identification of molecular mechanisms leading to the formation of unilamellar vesicles in the extrusion process. Finally, it was demonstrated that during the extrusion, lipids are not exchanged between vesicles, i.e., vesicles can divide but no membrane fusion or lipid exchange between bilayers was detected.

scholarly journals Arrayed lipid bilayer chambers allow single-molecule analysis of membrane transporter activity

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Rikiya Watanabe ◽  
Naoki Soga ◽  
Daishi Fujita ◽  
Kazuhito V. Tabata ◽  
Lisa Yamauchi ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Single Molecule ◽  
Membrane Transporter ◽  
Single Molecule Analysis
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