scholarly journals Embedding a Membrane Protein into an Enveloped Artificial Viral Replica

2022 ◽  
Author(s):  
Hiroto Furukawa ◽  
Hiroshi Inaba ◽  
Yoshihiro Sasaki ◽  
Kazunari Akiyoshi ◽  
Kazunori Matsuura
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Outer Surface ◽  
Enveloped Viruses

Natural enveloped viruses, in which nucleocapsids are covered with lipid bilayers, contain membrane proteins on the outer surface that are involved in diverse functions, such as adhesion and infection of...

Mutations in transmembrane proteins: diseases, evolutionary insights, prediction and comparison with globular proteins

2020 ◽  
Author(s):  
Jan Zaucha ◽  
Michael Heinzinger ◽  
A Kulandaisamy ◽  
Evans Kataka ◽  
Óscar Llorian Salvádor ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Protein Structures ◽  
Experimental Studies ◽  
Single Amino Acid ◽  
Evolutionary Information ◽  
Missense Variants ◽  
Current State ◽  
Aqueous Environments

Abstract Membrane proteins are unique in that they interact with lipid bilayers, making them indispensable for transporting molecules and relaying signals between and across cells. Due to the significance of the protein’s functions, mutations often have profound effects on the fitness of the host. This is apparent both from experimental studies, which implicated numerous missense variants in diseases, as well as from evolutionary signals that allow elucidating the physicochemical constraints that intermembrane and aqueous environments bring. In this review, we report on the current state of knowledge acquired on missense variants (referred to as to single amino acid variants) affecting membrane proteins as well as the insights that can be extrapolated from data already available. This includes an overview of the annotations for membrane protein variants that have been collated within databases dedicated to the topic, bioinformatics approaches that leverage evolutionary information in order to shed light on previously uncharacterized membrane protein structures or interaction interfaces, tools for predicting the effects of mutations tailored specifically towards the characteristics of membrane proteins as well as two clinically relevant case studies explaining the implications of mutated membrane proteins in cancer and cardiomyopathy.

scholarly journals Evidence for Membrane Complex Assembly in Nanoelectrospray Generated Lipid Bilayers

2019 ◽  
Author(s):  
Matthias Wilm
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Layered Structure ◽  
Protein Complexes ◽  
Complex Assembly ◽  
Membrane Complex ◽  
Detergent Extraction ◽  
Membrane Protein Complexes

1.AbstractNanoelectrospray can be used to generate a layered structure consisting of bipolar lipids, detergent-solubilized membrane proteins, and glycerol that self-assembles upon detergent extraction into one extended layer of a protein containing membrane. This manuscript presents the first evidence that this method might allow membrane protein complexes to assemble in this process.

scholarly journals Tryptophan, an Amino-Acid Endowed with Unique Properties and Its Many Roles in Membrane Proteins

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1032
Author(s):  
Sonia Khemaissa ◽  
Sandrine Sagan ◽  
Astrid Walrant
Keyword(s):  
Amino Acid ◽  
Membrane Proteins ◽  
Hydrogen Bonds ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Noncovalent Interactions ◽  
Chemical Properties ◽  
Protein Stabilization ◽  
Physico Chemical

Tryptophan is an aromatic amino acid with unique physico-chemical properties. It is often encountered in membrane proteins, especially at the level of the water/bilayer interface. It plays a role in membrane protein stabilization, anchoring and orientation in lipid bilayers. It has a hydrophobic character but can also engage in many types of interactions, such as π–cation or hydrogen bonds. In this review, we give an overview of the role of tryptophan in membrane proteins and a more detailed description of the underlying noncovalent interactions it can engage in with membrane partners.

Exploration of interactions between membrane proteins embedded in supported lipid bilayers and their antibodies by reflectometric interference spectroscopy-based sensing

The Analyst ◽  
2014 ◽  
Vol 139 (22) ◽  
pp. 6016-6021 ◽  
Author(s):  
Yoshikazu Kurihara ◽  
Tsuneo Sawazumi ◽  
Toshifumi Takeuchi
Keyword(s):  
Multidrug Resistance ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Model Membrane ◽  
Supported Lipid Bilayers ◽  
Reflectometric Interference Spectroscopy

A microfluidic reflectometric interference spectroscopy (RIfS)-based sensor was fabricated to investigate the activity of multidrug resistance-associated protein 1 (MRP1), applied as a model membrane protein.

scholarly journals Occupancy distributions of membrane proteins in heterogeneous liposome populations

2019 ◽  
Author(s):  
Lucy Cliff ◽  
Rahul Chadda ◽  
Janice L. Robertson
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Single Molecule ◽  
Skewed Distribution ◽  
Liposome Size ◽  
Protein Incorporation ◽  
Size Heterogeneity ◽  
The Right ◽  
And Function

AbstractMeasurements of membrane protein structure and function often rely on reconstituting the protein into lipid bilayers through the formation of liposomes. Many measurements conducted in proteoliposomes, e.g. transport rates, single-molecule dynamics, monomer-oligomer equilibrium, require some understanding of the occupancy statistics of the liposome population for correct interpretation of the results. In homogenous liposomes, this is easy to calculate as the act of protein incorporation can be described by the Poisson distribution. However, in reality, liposomes are heterogeneous, which alters the statistics of occupancy in several ways. Here, we determine the liposome occupancy distribution for membrane protein reconstitution while taking into account liposome size heterogeneity. We calculate the protein occupancy for a homogenous population of liposomes with radius r = 200 nm, representing an idealization of vesicles extruded through 400 nm pores and compare it to the right-skewed distribution of 400 nm 2:1 POPE:POPG vesicles. As is the case for E. coli polar lipids, this synthetic composition yields a sub-population of small liposomes, ∼25 nm in radius with a long tail of larger vesicles. Previously published microscopy data of the co-localization of the CLC-ec1 Cl-/H+ transporter with liposomes, and vesicle occupancy measurements using functional transport assays, shows agreement with the heterogeneous 2:1 POPE:POPG population. Next, distributions of 100 nm and 30 nm extruded 2:1 POPE:POPG liposomes are measured by cryo-electron microscopy, demonstrating that extrusion through smaller pores does not shift the peak, but reduces polydispersity arising from large liposomes. Single-molecule photobleaching analysis of CLC-ec1-Cy5 shows the 30 nm extruded population increases the ‘Poisson-dilution’ range, reducing the probability of vesicles with more than one protein at higher protein/lipid densities. These results demonstrate that the occupancy distributions of membrane proteins into vesicles can be accurately predicted in heterogeneous populations with experimental knowledge of the liposome size distribution.

scholarly journals Probing membrane protein properties using droplet interface bilayers

2019 ◽  
Vol 244 (8) ◽  
pp. 709-720 ◽  
Author(s):  
Maxwell Allen-Benton ◽  
Heather E Findlay ◽  
Paula J Booth
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Drug Targets ◽  
In Vitro Study ◽  
In Vitro Studies ◽  
Future Research ◽  
Functional Studies ◽  
Droplet Interface Bilayer

Integral membrane proteins comprise a large proportion of drug targets, yet are challenging to study in vitro due to their amphiphilic nature. Conducting useful functional in vitro studies requires an artificial membrane that can mimic the lipid environment of the biogenic membrane. Droplet interface bilayer technology provides a method to form artificial bilayers with a robustness and physicochemical complexity that has not previously been possible, facilitating more sophisticated in vitro studies of membrane proteins. This mini-review examines functional studies of membrane proteins that utilize droplet interface bilayers to date and comments on possible directions of future research. Observations from our own laboratory regarding the study of a flippase protein in droplet interface bilayers are also presented. Impact statement The paper presents a comprehensive review of integral membrane protein studies utilizing droplet interface bilayers. Droplet interface bilayers are a novel method of constructing artificial lipid bilayers with enhanced stability and physicochemical complexity compared to existing methods. Their unique morphology also suggests applications in the construction of synthetic biological systems and protocells. As well as serving as a guide to in vitro membrane protein functional studies using droplet interface bilayers in the literature to date, a novel in vitro study of a flippase protein in a droplet interface bilayer is presented.

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.

Self-assembling Peptide Detergent A6D Directly Associates with Bovine Rhodopsin and Forms Lipid-like Vesicles

2004 ◽  
Vol 845 ◽  
Author(s):  
Xiaojun Zhao ◽  
Yusuke Nagai ◽  
Shuguang Zhang
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Self Assembly ◽  
Protein Structures ◽  
Detergent Solution ◽  
Self Assembling ◽  
Bovine Rhodopsin ◽  
Hydrophobic Tail ◽  
New Type

ABSTRACTMembrane protein study critically depends on detergents, which are amphilhilic molecules containing a hydrophilic “head” and a hydrophobic “tail” to mimic biological lipid bilayers to stabilize membrane proteins. However, detergents are not fully equivalent to lipid bilayers and in fact they only partly mimic lipid bilayers function. Consequently, membrane proteins in detergent solution are more or less denatured because detergents can not effectively stabilize membrane protein structures. Therefore, it is urgent to develop new types of detergents for more effectively stabilizing membrane proteins. Previously, we have reported a new type of self-assembly peptide detergents containing a hydrophilic head composed of either a negatively charged aspartic acid or a positively charged lysine and a tail of hydrophobic amino acids of six connective alanines. This new peptide detergent has been shown to be more effective for protecting membrane protein PS I structure than that the conventional detergent does. However, what type of physical structures peptide detergent can form is unclear yet. Here we presented our AFM and DSL analysis of the peptide detergent A6D, which not only form mixed micelles with n-Octyl-beta-D-Glucoside (OG) to solubilize membrane protein rhodopsin, but also can mimic lipid bilayers to keep rhodopsin in lipid-like vesicles for its structure preservation.

TMCC3 localizes at the three-way junctions for the proper tubular network of the endoplasmic reticulum

2019 ◽  
Vol 476 (21) ◽  
pp. 3241-3260
Author(s):  
Sindhu Wisesa ◽  
Yasunori Yamamoto ◽  
Toshiaki Sakisaka
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Mammalian Cells ◽  
Coiled Coil ◽  
Transmembrane Domains ◽  
Domain Family ◽  
Coiled Coil Domain ◽  
U2os Cells ◽  
Er Membrane

The tubular network of the endoplasmic reticulum (ER) is formed by connecting ER tubules through three-way junctions. Two classes of the conserved ER membrane proteins, atlastins and lunapark, have been shown to reside at the three-way junctions so far and be involved in the generation and stabilization of the three-way junctions. In this study, we report TMCC3 (transmembrane and coiled-coil domain family 3), a member of the TEX28 family, as another ER membrane protein that resides at the three-way junctions in mammalian cells. When the TEX28 family members were transfected into U2OS cells, TMCC3 specifically localized at the three-way junctions in the peripheral ER. TMCC3 bound to atlastins through the C-terminal transmembrane domains. A TMCC3 mutant lacking the N-terminal coiled-coil domain abolished localization to the three-way junctions, suggesting that TMCC3 localized independently of binding to atlastins. TMCC3 knockdown caused a decrease in the number of three-way junctions and expansion of ER sheets, leading to a reduction of the tubular ER network in U2OS cells. The TMCC3 knockdown phenotype was partially rescued by the overexpression of atlastin-2, suggesting that TMCC3 knockdown would decrease the activity of atlastins. These results indicate that TMCC3 localizes at the three-way junctions for the proper tubular ER network.

Simulation studies of the interactions between membrane proteins and detergents

2005 ◽  
Vol 33 (5) ◽  
pp. 910-912 ◽  
Author(s):  
P.J. Bond ◽  
J. Cuthbertson ◽  
M.S.P. Sansom
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Self Assembly ◽  
Kinetic Mechanism ◽  
Coarse Grained ◽  
Simulation Studies ◽  
High Resolution Data ◽  
Biologically Relevant ◽  
Structure And Dynamics ◽  
Detergent Interactions

Interactions between membrane proteins and detergents are important in biophysical and structural studies and are also biologically relevant in the context of folding and transport. Despite a paucity of high-resolution data on protein–detergent interactions, novel methods and increased computational power enable simulations to provide a means of understanding such interactions in detail. Simulations have been used to compare the effect of lipid or detergent on the structure and dynamics of membrane proteins. Moreover, some of the longest and most complex simulations to date have been used to observe the spontaneous formation of membrane protein–detergent micelles. Common mechanistic steps in the micelle self-assembly process were identified for both α-helical and β-barrel membrane proteins, and a simple kinetic mechanism was proposed. Recently, simplified (i.e. coarse-grained) models have been utilized to follow long timescale transitions in membrane protein–detergent assemblies.

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