Two-Dimensional Continuous Extraction in Multiphase Lipid Bilayers To Separate, Enrich, and Sort Membrane-Bound Species

2013 ◽  
Vol 85 (14) ◽  
pp. 6696-6702 ◽  
Author(s):  
Ling Chao ◽  
Mark J. Richards ◽  
Chih-Yun Hsia ◽  
Susan Daniel
Keyword(s):  
Lipid Bilayers ◽  
Two Dimensional ◽  
Continuous Extraction ◽  
Membrane Bound

scholarly journals Nanogold as a Specific Marker for Electron Cryotomography

2009 ◽  
Vol 15 (3) ◽  
pp. 183-188 ◽  
Author(s):  
Yongning He ◽  
Grant J. Jensen ◽  
Pamela J. Bjorkman
Keyword(s):  
Lipid Bilayers ◽  
Outer Surface ◽  
Three Dimensional ◽  
Fc Receptor ◽  
Specific Marker ◽  
Neonatal Fc Receptor ◽  
Membrane Bound ◽  
Nanogold Particles ◽  
Intracellular Vesicles ◽  
Electron Cryotomography

AbstractWhile electron cryotomography (ECT) provides “molecular” resolution, three-dimensional images of unique biological specimens, sample crowdedness, and/or resolution limitations can make it difficult to identify specific macromolecular components. Here we used a 1.4 nm Nanogold® cluster specifically attached to the Fc fragment of IgG to monitor its interaction with the neonatal Fc receptor (FcRn), a membrane-bound receptor that transports IgG across cells in acidic intracellular vesicles. ECT was used to image complexes formed by Nanogold-labeled Fc bound to FcRn attached to the outer surface of synthetic liposomes. In the resulting three-dimensional reconstructions, 1.4 nm Nanogold particles were distributed predominantly along the interfaces where 2:1 FcRn-Fc complexes bridged adjacent lipid bilayers. These results demonstrate that the 1.4 nm Nanogold cluster is visible in tomograms of typically thick samples (∼250 nm) recorded with defocuses appropriate for large macromolecules and is thus an effective marker.

scholarly journals In Silico Study of the Mechanism of Binding of the N-Terminal Region of α Synuclein to Synaptic-Like Membranes

Life ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 98 ◽  
Author(s):  
Carlos Navarro-Paya ◽  
Maximo Sanz-Hernandez ◽  
Alfonso De Simone
Keyword(s):  
Lipid Bilayers ◽  
Conformational Transition ◽  
Md Simulations ◽  
Bound State ◽  
Terminal Region ◽  
Coarse Grained ◽  
Biological Behavior ◽  
In Silico Study ◽  
Membrane Bound ◽  
Presynaptic Protein

The membrane binding by α-synuclein (αS), a presynaptic protein whose aggregation is strongly linked with Parkinson’s disease, influences its biological behavior under functional and pathological conditions. This interaction requires a conformational transition from a disordered-unbound to a partially helical membrane-bound state of the protein. In the present study, we used enhanced coarse-grained MD simulations to characterize the sequence and conformational determinants of the binding to synaptic-like vesicles by the N-terminal region of αS. This region is the membrane anchor and is of crucial importance for the properties of the physiological monomeric state of αS as well as for its aberrant aggregates. These results identify the key factors that play a role in the binding of αS with synaptic lipid bilayers in both membrane-tethered and membrane-locked conformational states.

Structure of two-dimensional crystals of membrane-bound Na,K-ATPase as analyzed by correlation averaging

1985 ◽  
Vol 92 (1-2) ◽  
pp. 28-35 ◽  
Author(s):  
Hans Hebert ◽  
Elisabeth Skriver ◽  
Reiner Hegerl ◽  
Arvid B. Maunsbach
Keyword(s):  
Two Dimensional ◽  
Membrane Bound

scholarly journals Counting charges on membrane-bound peptides

2018 ◽  
Vol 9 (18) ◽  
pp. 4285-4298 ◽  
Author(s):  
Alicia C. McGeachy ◽  
Emily R. Caudill ◽  
Dongyue Liang ◽  
Qiang Cui ◽  
Joel A. Pedersen ◽  
...  
Keyword(s):  
Surface Charge ◽  
Lipid Bilayers ◽  
Surface Coverage ◽  
Supported Lipid Bilayers ◽  
Membrane Bound ◽  
Solid Water

Quantifying the number of charges on peptides bound to interfaces requires reliable estimates of (i) surface coverage and (ii) surface charge, both of which are notoriously difficult parameters to obtain, especially at solid/water interfaces. Here, we report the thermodynamics and electrostatics governing the interactions of l-lysine and l-arginine octamers (Lys8 and Arg8) with supported lipid bilayers prepared.

scholarly journals NPC2 facilitates bidirectional transfer of cholesterol between NPC1 and lipid bilayers, a step in cholesterol egress from lysosomes

2008 ◽  
Vol 105 (40) ◽  
pp. 15287-15292 ◽  
Author(s):  
Rodney E. Infante ◽  
Michael L. Wang ◽  
Arun Radhakrishnan ◽  
Hyock Joo Kwon ◽  
Michael S. Brown ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lipid Bilayers ◽  
Clinical Phenotype ◽  
Phosphatidylcholine Liposomes ◽  
Terminal Domain ◽  
Naturally Occurring ◽  
Membrane Bound ◽  
Niemann Pick ◽  
Lysosomal Proteins

Egress of lipoprotein-derived cholesterol from lysosomes requires two lysosomal proteins, polytopic membrane-bound Niemann–Pick C1 (NPC1) and soluble Niemann–Pick C2 (NPC2). The reason for this dual requirement is unknown. Previously, we showed that the soluble luminal N-terminal domain (NTD) of NPC1 (amino acids 25–264) binds cholesterol. This NTD is designated NPC1(NTD). We and others showed that soluble NPC2 also binds cholesterol. Here, we establish an in vitro assay to measure transfer of [3H]cholesterol between these two proteins and phosphatidylcholine liposomes. Whereas NPC2 rapidly donates or accepts cholesterol from liposomes, NPC1(NTD) acts much more slowly. Bidirectional transfer of cholesterol between NPC1(NTD) and liposomes is accelerated >100-fold by NPC2. A naturally occurring human mutant of NPC2 (Pro120Ser) fails to bind cholesterol and fails to stimulate cholesterol transfer from NPC1(NTD) to liposomes. NPC2 may be essential to deliver or remove cholesterol from NPC1, an interaction that links both proteins to the cholesterol egress process from lysosomes. These findings may explain how mutations in either protein can produce a similar clinical phenotype.

scholarly journals The Effect of Lipid Bilayers on Membrane-Bound Proteins

2015 ◽  
Vol 108 (2) ◽  
pp. 77a
Author(s):  
Kayla Sapp ◽  
Lutz Maibaum
Keyword(s):  
Lipid Bilayers ◽  
Membrane Bound

Molecular and global structure and dynamics of membranes and lipid bilayers

1990 ◽  
Vol 68 (9) ◽  
pp. 999-1012 ◽  
Author(s):  
E. Sackmann
Keyword(s):  
Lipid Bilayers ◽  
Plasma Membranes ◽  
Mechanical Stability ◽  
Dynamic Properties ◽  
Composite Membranes ◽  
Two Dimensional ◽  
Molecular Architecture ◽  
Present Contribution ◽  
Cell Plasma ◽  
Low Dimensionality

The cell plasma is a composite type of material that is made up of a two-dimensional liquid crystal (lipid–protein bilayer) to which a macromolecular network (the cytoskeleton) is loosely coupled. The latter may be approximately two dimensional as in the case of the erythrocytes or may extend throughout the whole cell cytoplasm. Owing to this combination of two states of matter, the membrane combines the dynamics and flexibility of a fluid with the mechanical stability of a solid. Owing to its low dimensionality, the local structure of the bilayer or the global shape of cells may be most effectively controlled and modulated by biochemical signals such as macromolecular adsorption. The present contribution deals with comparative studies of the local and global dynamic properties of biological and artificial membranes. In the first part the question of the physical basis of selective lipid–protein interaction mechanisms is addressed and the outstanding viscoelastic properties of plasma membranes and their role for local instabilities shape fluctuations of cells and the cell–substrate interaction are described. The second part deals with the molecular architecture and dynamics of composite membranes prepared by combining monomeric and macromolecular lipids. These model membranes open new possibilities to mimick complex mechanical processes of cell plasma membranes and to prepare low-dimensionality macromolecular solutions and gels. Finally, the use of such compound systems by nature to prepare the semipermeable protective layers of plant leaves, the so-called cuticle, is discussed. In analogy to plasma membranes, the local transport properties are modulated by variation of the liquid-crystalline state of the monomeric waxes.

scholarly journals Peptide-presenting two-dimensional protein matrix on supported lipid bilayers: An efficient platform for cell adhesion

2007 ◽  
Vol 2 (4) ◽  
pp. 165-172 ◽  
Author(s):  
Rémi Bérat ◽  
Murielle Rémy-Zolghadry ◽  
Céline Gounou ◽  
Claude Manigand ◽  
Sisareuth Tan ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Lipid Bilayers ◽  
Supported Lipid Bilayers ◽  
Two Dimensional ◽  
Protein Matrix
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