Local Changes in Lipid Composition to Match Membrane Curvature

Rolf J. Ryham

Molecular Based Mathematical Biology (2016)

  • Volume: 4, Issue: 1, page 26-35
  • ISSN: 2299-3266

Abstract

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A continuum mechanical model based on the Helfrich Hamiltonian is devised to investigate the coupling between lipid composition and membrane curvature. Each monolayer in the bilayer is modeled as a freely deformable surface with a director field for lipid orientation. A scalar field for the mole fraction of two lipid types accounts for local changes in composition. It allows lipids to access monolayer regions favorable to their intrinsic curvature at the expense of increasing entropic free energy. Hemifusion is one of the key fusion intermediates with regions of both positive and negative membrane curvature and where proteins must supply energy in order to bring about large elastic distortions. Using a numerical gradient descent scheme, minimal energy axisymmetric shapes of hemifusion diaphragms are calculated for varying radii. Previous studies assumed a fixed, weighted average for spontaneous curvature. Allowing for local changes in spontaneous curvature yields energies and forces of expansion significantly lower than those obtained from a fixed composition.

How to cite

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Rolf J. Ryham. "Local Changes in Lipid Composition to Match Membrane Curvature." Molecular Based Mathematical Biology 4.1 (2016): 26-35. <http://eudml.org/doc/287154>.

@article{RolfJ2016,
abstract = {A continuum mechanical model based on the Helfrich Hamiltonian is devised to investigate the coupling between lipid composition and membrane curvature. Each monolayer in the bilayer is modeled as a freely deformable surface with a director field for lipid orientation. A scalar field for the mole fraction of two lipid types accounts for local changes in composition. It allows lipids to access monolayer regions favorable to their intrinsic curvature at the expense of increasing entropic free energy. Hemifusion is one of the key fusion intermediates with regions of both positive and negative membrane curvature and where proteins must supply energy in order to bring about large elastic distortions. Using a numerical gradient descent scheme, minimal energy axisymmetric shapes of hemifusion diaphragms are calculated for varying radii. Previous studies assumed a fixed, weighted average for spontaneous curvature. Allowing for local changes in spontaneous curvature yields energies and forces of expansion significantly lower than those obtained from a fixed composition.},
author = {Rolf J. Ryham},
journal = {Molecular Based Mathematical Biology},
keywords = {Helfrich energy; membrane continuum mechanics; lipid bilayers; entropic penalty; spontaneous curvature; spontaneous curvature},
language = {eng},
number = {1},
pages = {26-35},
title = {Local Changes in Lipid Composition to Match Membrane Curvature},
url = {http://eudml.org/doc/287154},
volume = {4},
year = {2016},
}

TY - JOUR
AU - Rolf J. Ryham
TI - Local Changes in Lipid Composition to Match Membrane Curvature
JO - Molecular Based Mathematical Biology
PY - 2016
VL - 4
IS - 1
SP - 26
EP - 35
AB - A continuum mechanical model based on the Helfrich Hamiltonian is devised to investigate the coupling between lipid composition and membrane curvature. Each monolayer in the bilayer is modeled as a freely deformable surface with a director field for lipid orientation. A scalar field for the mole fraction of two lipid types accounts for local changes in composition. It allows lipids to access monolayer regions favorable to their intrinsic curvature at the expense of increasing entropic free energy. Hemifusion is one of the key fusion intermediates with regions of both positive and negative membrane curvature and where proteins must supply energy in order to bring about large elastic distortions. Using a numerical gradient descent scheme, minimal energy axisymmetric shapes of hemifusion diaphragms are calculated for varying radii. Previous studies assumed a fixed, weighted average for spontaneous curvature. Allowing for local changes in spontaneous curvature yields energies and forces of expansion significantly lower than those obtained from a fixed composition.
LA - eng
KW - Helfrich energy; membrane continuum mechanics; lipid bilayers; entropic penalty; spontaneous curvature; spontaneous curvature
UR - http://eudml.org/doc/287154
ER -

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