Differential dependencies on [Ca2+] and temperature of the monolayer spontaneous curvatures of DOPE, DOPA and cardiolipin: effects of modulating the strength of the inter-headgroup repulsion

Soft Matter ◽  
2015 ◽  
Vol 11 (20) ◽  
pp. 4041-4053 ◽  
Author(s):  
Y.-F. Chen ◽  
K.-Y. Tsang ◽  
W.-F. Chang ◽  
Z.-A. Fan
Keyword(s):  
Charge Density ◽  
Phase Behavior ◽  
Spontaneous Curvature ◽  
Cellular Functions

The measurements of spontaneous curvature for phospholipids differing in the headgroup charge density quantitatively and mechanistically reveal the importance of inter-headgroup repulsion to their phase behavior and cellular functions.

Charge-Density-Dominated Phase Behavior and Viscoelasticity of Polyelectrolyte Complex Coacervates

2019 ◽  
Vol 52 (13) ◽  
pp. 4957-4967 ◽  
Author(s):  
Jun Huang ◽  
Frances J. Morin ◽  
Jennifer E. Laaser
Keyword(s):  
Charge Density ◽  
Phase Behavior ◽  
Polyelectrolyte Complex

Phase Behavior of Aqueous Polyion-Surfactant Ion Complex Salts:  Effects of Polyion Charge Density†

2007 ◽  
Vol 111 (29) ◽  
pp. 8402-8410 ◽  
Author(s):  
Jens Norrman ◽  
Iseult Lynch ◽  
Lennart Piculell
Keyword(s):  
Charge Density ◽  
Phase Behavior ◽  
Complex Salts

Curvature Elasticity of Block Copolymers and the Structure of Emulsified Polymer Blends

1989 ◽  
Vol 177 ◽  
Author(s):  
Zhen-Gang Wang ◽  
S. A. Safran
Keyword(s):  
Free Energy ◽  
Block Copolymer ◽  
Polymer Blends ◽  
Phase Behavior ◽  
Elastic Properties ◽  
Interfacial Layer ◽  
Elastic Moduli ◽  
Spontaneous Curvature ◽  
Polymer Properties ◽  
Curvature Elasticity

ABSTRACTWe consider the curvature elastic properties of a layer of block copolymer at the interface between two incompatible homopolymers. We focus on the relation between the relative lengths of the blocks and the elastic properties of the interfacial layer which determines the phase behavior. The curvature elastic moduli K and K, as well as the spontaneous curvature, c0, are obtained. The curvature free energy is used to predict the relative stability of spherical, cylindrical, lamellar, and ordered bicontinuous saddle-shaped structures as functions of concentration and polymer properties.

scholarly journals Geometric coupling of helicoidal ramps and curvature-inducing proteins in organelle membranes

2019 ◽  
Author(s):  
Morgan Chabanon ◽  
Padmini Rangamani
Keyword(s):  
Minimal Surfaces ◽  
Complex Geometries ◽  
Spontaneous Curvature ◽  
Membrane Structures ◽  
Cellular Functions ◽  
Diverse Range ◽  
Elastic Membranes ◽  
Membrane Geometry ◽  
Membrane Bound ◽  
Shape Equation

AbstractCellular membranes display an incredibly diverse range of shapes, both in the plasma membrane and at membrane bound organelles. These morphologies are intricately related to cellular functions, enabling and regulating fundamental membrane processes. However, the biophysical mechanisms at the origin of these complex geometries are not fully understood from the standpoint of membrane-protein coupling. In this work, we focused on a minimal model of helicoidal ramps representative of specialized endoplasmic reticulum compartments. Given a helicoidal membrane geometry, we asked what is the distribution of spontaneous curvature required to maintain this shape at mechanical equilibrium? Based on the Helfrich energy of elastic membranes with spontaneous curvature, we derived the shape equation for minimal surfaces, and applied it to helicoids. We showed the existence of switches in the sign of the spontaneous curvature associated with geometric variations of the membrane structures. Furthermore, for a prescribed gradient of spontaneous curvature along the exterior boundaries, we identified configurations of the helicoidal ramps that are confined between two infinitely large energy barriers. Overall our results suggest possible mechanisms for geometric control of helicoidal ramps in membrane organelles based on curvature-inducing proteins.

scholarly journals Geometric coupling of helicoidal ramps and curvature-inducing proteins in organelle membranes

2019 ◽  
Vol 16 (158) ◽  
pp. 20190354 ◽  
Author(s):  
Morgan Chabanon ◽  
Padmini Rangamani
Keyword(s):  
Minimal Surfaces ◽  
Complex Geometries ◽  
Spontaneous Curvature ◽  
Membrane Structures ◽  
Cellular Functions ◽  
Diverse Range ◽  
Elastic Membranes ◽  
Membrane Geometry ◽  
Membrane Bound ◽  
Shape Equation

Cellular membranes display an incredibly diverse range of shapes, both in the plasma membrane and at membrane bound organelles. These morphologies are intricately related to cellular functions, enabling and regulating fundamental membrane processes. However, the biophysical mechanisms at the origin of these complex geometries are not fully understood from the standpoint of membrane–protein coupling. In this study, we focused on a minimal model of helicoidal ramps representative of specialized endoplasmic reticulum compartments. Given a helicoidal membrane geometry, we asked what is the distribution of spontaneous curvature required to maintain this shape at mechanical equilibrium? Based on the Helfrich energy of elastic membranes with spontaneous curvature, we derived the shape equation for minimal surfaces, and applied it to helicoids. We showed the existence of switches in the sign of the spontaneous curvature associated with geometric variations of the membrane structures. Furthermore, for a prescribed gradient of spontaneous curvature along the exterior boundaries, we identified configurations of the helicoidal ramps that are confined between two infinitely large energy barriers. Overall our results suggest possible mechanisms for geometric control of helicoidal ramps in membrane organelles based on curvature-inducing proteins.

Impact of pH, ionic strength and chitosan charge density on chitosan/casein complexation and phase behavior

2019 ◽  
Vol 208 ◽  
pp. 133-141 ◽  
Author(s):  
Lan Ding ◽  
Yan Huang ◽  
XiXi Cai ◽  
Shaoyun Wang
Keyword(s):  
Ionic Strength ◽  
Charge Density ◽  
Phase Behavior

scholarly journals Charge Density and Hydrophobicity-Dominated Regimes in the Phase Behavior of Complex Coacervates

2021 ◽  
Author(s):  
Jun Huang ◽  
Jennifer Laaser
Keyword(s):  
Charge Density ◽  
Phase Behavior ◽  
Complex Salt ◽  
Side Chain ◽  
Charge Densities ◽  
Wide Range ◽  
Optical Turbidity ◽  
Chain Lengths ◽  
Coacervate Phase

<div>The role of hydrophobicity, and particularly nonionic hydrophobic comonomers, on the phase behavior of polyelectrolyte complex coacervates is not well-understood. Here, we address this problem by synthesizing a library of polymers with a wide range of charge densities and nonionic hydrophobic side chain lengths, and characterizing their phase behavior by optical turbidity. The polymers were prepared by post-polymerization modification of poly(N-acryloxy succinimide), targeting charge densities between 40 and 100% and nonionic aliphatic sidechains with lengths from 0 to 12 carbons long. Turbidity measurements on pairs of polycations and polyanions with matched charge densities and nonionic sidechain lengths revealed a complex salt response with distinct charge density-dominated and hydrophobicity-dominated regimes. The polymer solubilities were not directly correlated with the phase behavior of the coacervates, indicating the difficulty of understanding the coacervate phase behavior in terms of the polymer-water interaction parameter. This result suggests that there is significant room for further work to understand the mechanisms by which specific molecular-scale interactions moderate the phase behavior of complex coacervates.</div>

Sign in / Sign up

Export Citation Format

Share Document