title: Investigating the Structure of Multicomponent Gel-Phase Lipid Bilayers.
abstract: Single- and multicomponent lipid bilayers of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphatidylcholine (DSPC), isostearyl isostearate, and heptadecanoyl heptadecanoate in the gel phase are studied via molecular dynamics simulations. It is shown that the structural properties of multicomponent bilayers can deviate strongly from the structures of their single-component counterparts. Specifically, the lipid mixtures are shown to adopt a compact packing by offsetting the positioning depths at which different lipid species are located in the bilayer. This packing mechanism affects the area per lipid, the bilayer height, and the chain tilt angles and has important consequences for other bilayer properties, such as interfacial hydrogen bonding and bilayer permeability. In particular, the simulations suggest that bilayers containing isostearyl isostearate or heptadecanoyl heptadecanoate are less permeable than pure 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine or DSPC bilayers. Furthermore, hydrogen-bond analysis shows that the residence times of lipid-water hydrogen bonds depend strongly on the bilayer composition, with longer residence times for bilayers that have a higher DSPC content. The findings illustrate and explain the fundamental differences between the properties of single- and multicomponent bilayers.
authors: Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, Tennessee.
authors: Remco
authors: R
authors: Hartkamp
authors: Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, Tennessee.
authors: Timothy C
authors: TC
authors: Moore
authors: Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, Tennessee.
authors: Christopher R
authors: CR
authors: Iacovella
authors: GlaxoSmithKline Consumer Healthcare, Warren, New Jersey.
authors: Michael A
authors: MA
authors: Thompson
authors: GlaxoSmithKline Consumer Healthcare, Warren, New Jersey.
authors: Pallav A
authors: PA
authors: Bulsara
authors: GlaxoSmithKline Consumer Healthcare, Warren, New Jersey.
authors: David J
authors: DJ
authors: Moore
authors: Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee; Multiscale Modeling and Simulation (MuMS) Center, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee. Electronic address: c.mccabe@vanderbilt.edu.
authors: Clare
authors: C
authors: McCabe
mesh_terms: D005782:Gels; D006860:Hydrogen Bonding; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D014867:Water / Q000737:chemistry
chemical_list: D005782:Gels; D008051:Lipid Bilayers; D014867:Water