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Title: Effect of Ceramide Tail Length on the Structure of Model Stratum Corneum Lipid Bilayers

Abstract

Lipid bilayers composed of non-hydroxy sphingosine ceramide (CER NS), cholesterol (CHOL), and free fattyacids (FFAs), which are components of the human skin barrier, are studied via molecular dynamics simulations. Since mixturesof these lipids exist in dense gel phases with little molecular mobility at physiological conditions, care must be taken to ensurethat the simulations become decorrelated from the initial conditions. Thus, we propose and validate an equilibration protocolbased on simulated tempering, in which the simulation takes a random walk through temperature space, allowing the systemto break out of metastable configurations and hence become decorrelated from its initial configuration. After validating the equil-ibration protocol, which we refer to as random-walk molecular dynamics, the effects of the lipid composition and ceramide taillength on bilayer properties are studied. Systems containing pure CER NS, CER NS þ CHOL, and CER NS þ CHOL þ FFA, withthe CER NS fatty acid tail length varied within each CER NS-CHOL-FFA composition, are simulated. The bilayer thickness isfound to depend on the structure of the center of the bilayer, which arises as a result of the tail-length asymmetry betweenthe lipids studied. The hydrogen bonding between the lipid headgroups and with water is found to change with the overall lipidcomposition,more » but is mostly independent of the CER fatty acid tail length. Subtle differences in the lateral packing of the lipid tailsare also found as a function of CER tail length. Overall, these results provide insight into the experimentally observed trend ofaltered barrier properties in skin systems where there are more CERs with shorter tails present.« less

Authors:
 [1];  [1];  [1];  [2];  [3]
  1. Vanderbilt University, Nashville, Tennessee (United States). Department of Chemical and Biomolecular Engineering, Multiscale Modeling and Simulation Center
  2. Colorado School of Mines, Golden, CO (United States). Department of Chemical and Biological Engineering
  3. Vanderbilt University, Nashville, Tennessee (United States). Department of Chemical and Biomolecular Engineering, Multiscale Modeling and Simulation Center, Department of Chemistry
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory, Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC).
Sponsoring Org.:
USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21)
OSTI Identifier:
1462511
DOE Contract Number:  
AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Biophysical Journal
Additional Journal Information:
Journal Volume: 114; Journal Issue: 1; Journal ID: ISSN 0006-3495
Publisher:
Elsevier
Country of Publication:
United States
Language:
English

Citation Formats

Moore, Timothy C., Hartkamp, Remco, Iacovella, Christopher R., Bunge, Annette L., and McCabe, Clare. Effect of Ceramide Tail Length on the Structure of Model Stratum Corneum Lipid Bilayers. United States: N. p., 2018. Web. doi:10.1016/j.bpj.2017.10.031.
Moore, Timothy C., Hartkamp, Remco, Iacovella, Christopher R., Bunge, Annette L., & McCabe, Clare. Effect of Ceramide Tail Length on the Structure of Model Stratum Corneum Lipid Bilayers. United States. doi:10.1016/j.bpj.2017.10.031.
Moore, Timothy C., Hartkamp, Remco, Iacovella, Christopher R., Bunge, Annette L., and McCabe, Clare. Mon . "Effect of Ceramide Tail Length on the Structure of Model Stratum Corneum Lipid Bilayers". United States. doi:10.1016/j.bpj.2017.10.031.
@article{osti_1462511,
title = {Effect of Ceramide Tail Length on the Structure of Model Stratum Corneum Lipid Bilayers},
author = {Moore, Timothy C. and Hartkamp, Remco and Iacovella, Christopher R. and Bunge, Annette L. and McCabe, Clare},
abstractNote = {Lipid bilayers composed of non-hydroxy sphingosine ceramide (CER NS), cholesterol (CHOL), and free fattyacids (FFAs), which are components of the human skin barrier, are studied via molecular dynamics simulations. Since mixturesof these lipids exist in dense gel phases with little molecular mobility at physiological conditions, care must be taken to ensurethat the simulations become decorrelated from the initial conditions. Thus, we propose and validate an equilibration protocolbased on simulated tempering, in which the simulation takes a random walk through temperature space, allowing the systemto break out of metastable configurations and hence become decorrelated from its initial configuration. After validating the equil-ibration protocol, which we refer to as random-walk molecular dynamics, the effects of the lipid composition and ceramide taillength on bilayer properties are studied. Systems containing pure CER NS, CER NS þ CHOL, and CER NS þ CHOL þ FFA, withthe CER NS fatty acid tail length varied within each CER NS-CHOL-FFA composition, are simulated. The bilayer thickness isfound to depend on the structure of the center of the bilayer, which arises as a result of the tail-length asymmetry betweenthe lipids studied. The hydrogen bonding between the lipid headgroups and with water is found to change with the overall lipidcomposition, but is mostly independent of the CER fatty acid tail length. Subtle differences in the lateral packing of the lipid tailsare also found as a function of CER tail length. Overall, these results provide insight into the experimentally observed trend ofaltered barrier properties in skin systems where there are more CERs with shorter tails present.},
doi = {10.1016/j.bpj.2017.10.031},
journal = {Biophysical Journal},
issn = {0006-3495},
number = 1,
volume = 114,
place = {United States},
year = {2018},
month = {1}
}