Charge-selective membrane protein patterning with proteoliposomes

RSC Advances ◽  
2015 ◽  
Vol 5 (7) ◽  
pp. 5183-5191
Author(s):  
Heesuk Kim ◽  
Keel Yong Lee ◽  
Soo Ryeon Ryu ◽  
Kwang-Hwan Jung ◽  
Tae Kyu Ahn ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Lipid Bilayers ◽  
Transmembrane Protein ◽  
Protein Patterning ◽  
Lipid Layer ◽  
Selective Membrane ◽  
Novel Method

A novel method to fabricate transmembrane protein (TP) embedded lipid bilayers has been developed, resulting in an immobilized, but biologically functioning TP embedded lipid layer precisely in the targeted patterns.

scholarly journals Controlling transmembrane protein concentration and orientation in supported lipid bilayers

2017 ◽  
Vol 53 (30) ◽  
pp. 4250-4253 ◽  
Author(s):  
P. Bao ◽  
M. L. Cartron ◽  
K. H. Sheikh ◽  
B. R. G. Johnson ◽  
C. N. Hunter ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Lipid Bilayers ◽  
Electric Fields ◽  
Protein Concentration ◽  
Transmembrane Protein ◽  
Fold Increase ◽  
Supported Lipid Bilayers

The trans-membrane protein–proteorhodopsin (pR) has been incorporated into supported lipid bilayers (SLB). In-plane electric fields have been used to manipulate the orientation and concentration of these proteins, within the SLB, through electrophoresis leading to a 25-fold increase concentration of pR.

scholarly journals A macroscopic H+and Cl−ions pump via reconstitution of EcClC membrane proteins in lipidic cubic mesophases

2016 ◽  
Vol 113 (27) ◽  
pp. 7491-7496 ◽  
Author(s):  
Chiara Speziale ◽  
Livia Salvati Manni ◽  
Cristina Manatschal ◽  
Ehud M. Landau ◽  
Raffaele Mezzenga
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Protein Crystallization ◽  
Structural Complexity ◽  
Proton Exchange ◽  
General Strategy ◽  
External Bias ◽  
Selective Membrane ◽  
A Charge

Functional reconstitution of membrane proteins within lipid bilayers is crucial for understanding their biological function in living cells. While this strategy has been extensively used with liposomes, reconstitution of membrane proteins in lipidic cubic mesophases presents significant challenges related to the structural complexity of the lipid bilayer, organized on saddle-like minimal surfaces. Although reconstitution of membrane proteins in lipidic cubic mesophases plays a prominent role in membrane protein crystallization, nanotechnology, controlled drug delivery, and pathology of diseased cells, little is known about the molecular mechanism of protein reconstitution and about how transport properties of the doped mesophase mirror the original molecular gating features of the reconstituted membrane proteins. In this work we design a general strategy to demonstrate correct functional reconstitution of active and selective membrane protein transporters in lipidic mesophases, exemplified by the bacterial ClC exchanger fromEscherichia coli(EcClC) as a model ion transporter. We show that its correct reconstitution in the lipidic matrix can be used to generate macroscopic proton and chloride pumps capable of selectively transporting charges over the length scale of centimeters. By further exploiting the coupled chloride/proton exchange of this membrane protein and by combining parallel or antiparallel chloride and proton gradients, we show that the doped mesophase can operate as a charge separation device relying only on the reconstituted EcClC protein and an external bias potential. These results may thus also pave the way to possible applications in supercapacitors, ion batteries, and molecular pumps.

scholarly journals Unraveling membrane properties at the organelle-level with LipidDyn

2022 ◽  
Author(s):  
Simone Scrima ◽  
Matteo Tiberti ◽  
Alessia Campo ◽  
Elisabeth Corcelle-Termeau ◽  
Delphine Judith ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Lipid Bilayers ◽  
Protein Interactions ◽  
Transmembrane Protein ◽  
Md Simulations ◽  
Membrane Properties ◽  
Cellular Membranes ◽  
Simulation Data ◽  
Membrane Function ◽  
Cellular Environment

Cellular membranes are formed from many different lipids in various amounts and proportions depending on the subcellular localization. The lipid composition of membranes is sensitive to changes in the cellular environment, and their alterations are linked to several diseases, including cancer. Lipids not only form lipid-lipid interactions but also interact with other biomolecules, including proteins, profoundly impacting each other. Molecular dynamics (MD) simulations are a powerful tool to study the properties of cellular membranes and membrane-protein interactions on different timescales and at varying levels of resolution. Over the last few years, software and hardware for biomolecular simulations have been optimized to routinely run long simulations of large and complex biological systems. On the other hand, high-throughput techniques based on lipidomics provide accurate estimates of the composition of cellular membranes at the level of subcellular compartments. The community needs computational tools for lipidomics and simulation data effectively interacting to better understand how changes in lipid compositions impact membrane function and structure. Lipidomic data can be analyzed to design biologically relevant models of membranes for MD simulations. Similar applications easily result in a massive amount of simulation data where the bottleneck becomes the analysis of the data to understand how membrane properties and membrane-protein interactions are changing in the different conditions. In this context, we developed LipidDyn, an in silico pipeline to streamline the analyses of MD simulations of membranes of different compositions. Once the simulations are collected, LipidDyn provides average properties and time series for several membrane properties such as area per lipid, thickness, diffusion motions, the density of lipid bilayers, and lipid enrichment/depletion. The calculations exploit parallelization and the pipelines include graphical outputs in a publication-ready form. We applied LipidDyn to different case studies to illustrate its potential, including membranes from cellular compartments and transmembrane protein domains. LipidDyn is implemented in Python and relies on open-source libraries. LipidDyn is available free of charge under the GNU General Public License from https://github.com/ELELAB/LipidDyn.

scholarly journals Predicting the Structure and Dynamics of Membrane Protein GerAB from Bacillus subtilis

2021 ◽  
Vol 22 (7) ◽  
pp. 3793
Author(s):  
Sophie Blinker ◽  
Jocelyne Vreede ◽  
Peter Setlow ◽  
Stanley Brul
Keyword(s):  
Bacillus Subtilis ◽  
Membrane Protein ◽  
Spore Germination ◽  
Structural Information ◽  
Transmembrane Protein ◽  
Homology Modelling ◽  
Water Channel ◽  
Md Simulations ◽  
Integral Membrane Protein ◽  
Starting Point

Bacillus subtilis forms dormant spores upon nutrient depletion. Germinant receptors (GRs) in spore’s inner membrane respond to ligands such as L-alanine, and trigger spore germination. In B. subtilis spores, GerA is the major GR, and has three subunits, GerAA, GerAB, and GerAC. L-Alanine activation of GerA requires all three subunits, but which binds L-alanine is unknown. To date, how GRs trigger germination is unknown, in particular due to lack of detailed structural information about B subunits. Using homology modelling with molecular dynamics (MD) simulations, we present structural predictions for the integral membrane protein GerAB. These predictions indicate that GerAB is an α-helical transmembrane protein containing a water channel. The MD simulations with free L-alanine show that alanine binds transiently to specific sites on GerAB. These results provide a starting point for unraveling the mechanism of L-alanine mediated signaling by GerAB, which may facilitate early events in spore germination.

scholarly journals Cholesterol Increases Lipid Binding Rate and Changes Binding Behavior of Bacillus thuringiensis Cytolytic Protein

2018 ◽  
Vol 19 (12) ◽  
pp. 3819 ◽  
Author(s):  
Sudarat Tharad ◽  
Öykü Üzülmez ◽  
Boonhiang Promdonkoy ◽  
José Toca-Herrera
Keyword(s):  
Bacillus Thuringiensis ◽  
Lipid Bilayers ◽  
Mammalian Cells ◽  
Layer Structure ◽  
Cholesterol Content ◽  
Lipid Binding ◽  
Lipid Layer ◽  
Binding Behavior ◽  
Binding Rate ◽  
Ring Shape

Cytolytic protein (Cyt) is a member of insecticidal proteins produced by Bacillus thuringiensis. Cyt protein has activity against insect cells and mammalian cells, which differ in lipid and cholesterol composition. This study presents the lipid binding behavior of Cyt2Aa2 protein on model membranes containing different levels of cholesterol content by combining Quartz Crystal Microbalance with Dissipation (QCM-D) and Atomic Force Microscopy (AFM). QCM-D results revealed that cholesterol enhances the binding rate of Cyt2Aa2 protein onto lipid bilayers. In addition, the thicker lipid bilayer was observed for the highest cholesterol content. These results were confirmed by AFM. The analysis of protein surface coverage as a function of time showed a slower process for 5:0 and 5:0.2 (POPC:Chol) ratios than for 5:1 and 5:2 (POPC:Chol) ratios. Significantly, the Cyt2Aa2-lipid binding behavior and the protein–lipid layer were different for the 5:3 (POPC:Chol) ratio. Furthermore, AFM images revealed a transformation of Cyt2Aa2/lipid layer structure from strip pattern to ring shape structures (which showed a strong repulsion with AFM tip). In summary, cholesterol increases the binding rate and alters the lipid binding behavior of Cyt2Aa2 protein, although it is not required for Cyt2Aa2 protein binding onto lipid bilayers.

scholarly journals Detection of drug-induced conformational change of a transmembrane protein in lipid bilayers using site-directed spin labeling

2012 ◽  
Vol 22 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Jessica L. Thomaston ◽  
Phuong A. Nguyen ◽  
Emily C. Brown ◽  
Mary Alice Upshur ◽  
Jun Wang ◽  
...  
Keyword(s):  
Conformational Change ◽  
Lipid Bilayers ◽  
Transmembrane Protein ◽  
Spin Labeling ◽  
Drug Induced ◽  
Site Directed Spin Labeling

scholarly journals Poly(catecholamine) Coating and Biofunctionalization of CsPbBr3 Microcrystals

2021 ◽  
Author(s):  
Sangyeon Cho ◽  
Seok-Hyun Yun
Keyword(s):  
Lipid Bilayers ◽  
Environmental Stability ◽  
Live Cells ◽  
Functional Coatings ◽  
Common Strategy ◽  
Novel Method ◽  
Halide Perovskites ◽  
The Stability ◽  
New Applications

<p>Lead halide perovskites (LHP) microcrystals are promising materials for various optoelectronic applications. Surface coating on particles is a common strategy to improve their functionality and environmental stability, but LHP is not amenable to most coating chemistries because of its intrinsic weakness against polar solvents. Here, we describe a novel method of synthesizing LHP microcrystals in a super-saturated polar solvent using sonochemistry and applying various functional coatings on individual microcrystals <i>in situ</i>. We synthesize cesium lead bromine perovskite (CsPbBr<sub>3</sub>) microparticles capped with organic poly-norepinephrine (pNE) layers. The catechol group of pNE coordinates to bromine-deficient lead atoms, forming a defect-passivating and diffusion-blocking shell. The pNE layer enhances the stability of CsPbBr<sub>3</sub> in water by 2,000-folds, enabling bright luminescence and lasing from single microcrystals in water. Furthermore, the pNE shell permits biofunctionalization with proteins, small molecules, and lipid bilayers. Luminescence from CsPbBr<sub>3</sub> microcrystals is sustained in water over 1 hour and observed in live cells. The functionalization method may enable new applications of LHP particles in water-rich environments.<b></b></p>

scholarly journals Lipid bilayer induces contraction of the denatured state ensemble of a helical-bundle membrane protein

2021 ◽  
Vol 119 (1) ◽  
pp. e2109169119
Author(s):  
Kristen A. Gaffney ◽  
Ruiqiong Guo ◽  
Michael D. Bridges ◽  
Shaima Muhammednazaar ◽  
Daoyang Chen ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Limited Proteolysis ◽  
Water Soluble ◽  
Disordered Proteins ◽  
Resonance Spectroscopy ◽  
Denatured State ◽  
E Coli ◽  
State Ensemble

Defining the denatured state ensemble (DSE) and disordered proteins is essential to understanding folding, chaperone action, degradation, and translocation. As compared with water-soluble proteins, the DSE of membrane proteins is much less characterized. Here, we measure the DSE of the helical membrane protein GlpG of Escherichia coli (E. coli) in native-like lipid bilayers. The DSE was obtained using our steric trapping method, which couples denaturation of doubly biotinylated GlpG to binding of two streptavidin molecules. The helices and loops are probed using limited proteolysis and mass spectrometry, while the dimensions are determined using our paramagnetic biotin derivative and double electron–electron resonance spectroscopy. These data, along with our Upside simulations, identify the DSE as being highly dynamic, involving the topology changes and unfolding of some of the transmembrane (TM) helices. The DSE is expanded relative to the native state but only to 15 to 75% of the fully expanded condition. The degree of expansion depends on the local protein packing and the lipid composition. E. coli’s lipid bilayer promotes the association of TM helices in the DSE and, probably in general, facilitates interhelical interactions. This tendency may be the outcome of a general lipophobic effect of proteins within the cell membranes.

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