Surface-Bound Membrane-Mimetic Assemblies: Electrostatic Attributes of Integral Membrane Proteins

1988 ◽  
Author(s):  
H. G. Smith
Keyword(s):  
Membrane Proteins ◽  
Integral Membrane Proteins ◽  
Membrane Mimetic

scholarly journals Mass Photometry of Membrane Proteins

2020 ◽  
Author(s):  
Anna Olerinyova ◽  
Adar Sonn Segev ◽  
Joseph Gault ◽  
Cedric Eichmann ◽  
Johannes Schimpf ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Membrane Proteins ◽  
Integral Membrane Proteins ◽  
Membrane Protein Structure ◽  
Cellular Lipid ◽  
Critical Factors ◽  
Potassium Channel Kcsa ◽  
Membrane Mimetic ◽  
Particle Level ◽  
Lipid Nanodiscs

Integral membrane proteins (IMPs) are biologically highly significant but challenging to study because they require maintaining a cellular lipid - like environment. Here, we explore the application of mass photometry (MP) to IMPs and membrane mimetic systems at the single particle level. We apply MP to amphipathic vehicles, such as detergents and amphipols, as well as to lipid and native nanodiscs, characterising the particle size, sample purity and heterogeneity. Using methods established for cryogenic electron microscopy, we eliminate detergent background, enabling high - resolution studies of membrane protein structure and interactions. We find evidence that, when extracted from native membranes using native styrene - maleic acid nanodiscs, the potassium channel KcsA is present as a dimer of tetramers - in contrast to results obtained using detergent purification. Finally, using lipid nanodiscs, we show that MP can help distinguish between functional and non - functional nanodisc assemblies, as well as determine the critical factors for lipid nanodisc formation.

Image Analysis of Intramembrane Particles in Freeze-Fractured Biomembranes Using Computer Simulation Techniques

1975 ◽  
Vol 33 ◽  
pp. 214-215
Author(s):  
D.J. Benefiel ◽  
R.S. Weinstein
Keyword(s):  
Membrane Proteins ◽  
Freeze Fracture ◽  
Integral Membrane Proteins ◽  
Systematic Evaluation ◽  
Intramembrane Particles ◽  
Modeling Methods ◽  
Simulation Techniques ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron ◽  
Computer Simulation Techniques

Intramembrane particles (IMP or MAP) are components of most biomembranes. They are visualized by freeze-fracture electron microscopy, and they probably represent replicas of integral membrane proteins. The presence of MAP in biomembranes has been extensively investigated but their detailed ultrastructure has been largely ignored. In this study, we have attempted to lay groundwork for a systematic evaluation of MAP ultrastructure. Using mathematical modeling methods, we have simulated the electron optical appearances of idealized globular proteins as they might be expected to appear in replicas under defined conditions. By comparing these images with the apearances of MAPs in replicas, we have attempted to evaluate dimensional and shape distortions that may be introduced by the freeze-fracture technique and further to deduce the actual shapes of integral membrane proteins from their freezefracture images.

How Do Lipids Affect the Structure and Function of Integral Membrane Proteins

2012 ◽  
Vol 28 (11) ◽  
pp. 866
Author(s):  
Jie HENG ◽  
Yan WU ◽  
Xianping WANG ◽  
Kai ZHANG
Keyword(s):  
Membrane Proteins ◽  
Structure And Function ◽  
Integral Membrane Proteins ◽  
And Function

3D Crystallization and Structural Studies of Integral Membrane Proteins in Lipidic Cubic phases

2000 ◽  
Vol 56 (s1) ◽  
pp. s83-s83
Author(s):  
P. Nollert ◽  
M. L. Chiu ◽  
M. C. Loewen ◽  
A. Royant ◽  
H. Behrhali ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Integral Membrane Proteins ◽  
Structural Studies ◽  
Cubic Phases

scholarly journals Lipid Transporters Beam Signals from Cell Membranes

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 562
Author(s):  
Miliça Ristovski ◽  
Danny Farhat ◽  
Shelly Ellaine M. Bancud ◽  
Jyh-Yeuan Lee
Keyword(s):  
Membrane Proteins ◽  
Lipid Bilayers ◽  
Lipid Composition ◽  
Structural Integrity ◽  
Current Knowledge ◽  
Integral Membrane Proteins ◽  
Cellular Membranes ◽  
Cytoplasmic Proteins ◽  
Lipid Transporters

Lipid composition in cellular membranes plays an important role in maintaining the structural integrity of cells and in regulating cellular signaling that controls functions of both membrane-anchored and cytoplasmic proteins. ATP-dependent ABC and P4-ATPase lipid transporters, two integral membrane proteins, are known to contribute to lipid translocation across the lipid bilayers on the cellular membranes. In this review, we will highlight current knowledge about the role of cholesterol and phospholipids of cellular membranes in regulating cell signaling and how lipid transporters participate this process.

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