Molecular View of Phase Coexistence in Lipid Monolayers.
We used computer simulations to study the effect of phase separation on the properties of lipid monolayers. This is important for understanding the lipid-lipid interactions underlying lateral heterogeneity (rafts) in biological membranes and the role of domains in the regulation of surface tension b...
| Published in: | Journal of the American Chemical Society Vol. 134; no. 42; pp. 17543 - 17554 |
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| Main Authors: | , , |
| Format: | Article |
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American Chemical Society
10/24/2012
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| Online Access: | View this record in EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=83147029&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 83147029 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 10/24/2012 vid: 134 iid: 42 pid: 997 pub: American Chemical Society artinfo: ui: 83147029 10.1021/ja304792p ppf: 17543 ppct: 11 formats: tig: atl: Molecular View of Phase Coexistence in Lipid Monolayers. aug: au: Baoukina, Svetlana Mendez-Villuendas, Eduardo Tieleman, D. Peter affil: Department of Biological Sciences and Institute for Biocomplexity and Informatics, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4 su: Monomolecular films Lipids Computer simulation Heterogeneity Molecular dynamics Chemical decomposition Cluster analysis (Statistics) Phase transitions sug: subj: Monomolecular films Lipids Computer simulation Heterogeneity Molecular dynamics Chemical decomposition Cluster analysis (Statistics) Phase transitions ab: We used computer simulations to study the effect of phase separation on the properties of lipid monolayers. This is important for understanding the lipid-lipid interactions underlying lateral heterogeneity (rafts) in biological membranes and the role of domains in the regulation of surface tension by lung surfactant. Molecular dynamics simulations with the coarse-grained MARTINI force field were employed to model large length (80 nm in lateral dimension) and time (tens of microseconds) scales. Lipid mixtures containing saturated and unsaturated lipids and cholesterol were investigated under varying surface tension and temperature. We reproduced compositional lipid demixing and the coexistence of liquid-expanded and liquid-condensed phases as well as liquid-ordered and liquid-disordered phases. Formation of the more ordered phase was induced by lowering the surface tension or temperature. Phase transformations occurred via either nucleation or spinodal decomposition. In nucleation, multiple domains formed initially and subsequently merged. Using cluster analysis combined with Voronoi tessellation, we characterized the partial areas of the lipids in each phase, the phase composition, the boundary length, and the line tension under varying surface tension. We calculated the growth exponents for nucleation and spinodal decomposition using a dynamical scaling hypothesis. At low surface tensions, liquid-ordered domains manifest spontaneous curvature. Lateral diffusion of lipids is significantly slower in the more ordered phase, as expected. The presence of domains increased the monolayer surface viscosity, in particular as a result of domain reorganization under shear. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2012 holdings: @attributes: islocal: N |
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