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dc.contributor.author
Rosetti, Carla Mariana
dc.contributor.author
Pastorino, Claudio
dc.date.available
2023-02-28T12:39:11Z
dc.date.issued
2012-02
dc.identifier.citation
Rosetti, Carla Mariana; Pastorino, Claudio; Comparison of Ternary Bilayer Mixtures with Asymmetric or Symmetric Unsaturated Phosphatidylcholine Lipids by Coarse Grained Molecular Dynamics Simulations; American Chemical Society; Journal of Physical Chemistry B; 116; 11; 2-2012; 3525-3537
dc.identifier.issn
1520-6106
dc.identifier.uri
http://hdl.handle.net/11336/189047
dc.description.abstract
We studied the phase behavior of various ternary bilayer mixtures composed of cholesterol, an unsaturated lipid, and a fully saturated lipid, by means of molecular dynamics simulations of the MARTINI(1) coarse grain model. We aimed at comparing lateral organization and local properties of bilayers containing phosphatidylcholine (PC) lipids, either with two unsaturated tails (symmetric), or one unsaturated and one saturated tail (asymmetric), as the low-melting component of the mixture. The number of unsaturations per chain was systematically varied in both classes of unsaturated lipids, to account for its consequences in segregation. In the asymmetric unsaturated PCs, the saturated tail was kept identical to the hydrophobic chains of the fully saturated lipid component. Membranes with a symmetric or an asymmetric unsaturated lipid, with the same kind of unsaturated chain, show different phase behavior. Symmetric polyunsaturated PCs set the separation in two phases. Instead, the asymmetric polyunsaturated lipids induced nonideal mixing of components in single-phase bilayers. A significative drop of temperature, within the accessible temperature range, enhances the segregation in mixtures with the more unsaturated asymmetric PC, but still within a single phase. This different phase behavior between membranes with symmetric and asymmetric unsaturated PCs is also observed for lipids with the same total number of unsaturations. On the other hand, the degree of unsaturation per se enhances the segregation, by increasing the composition fluctuations in single-phase membranes with asymmetric PC lipids, and raising the line tension in the two-phase bilayer mixtures with symmetric polyunsaturated PCs. Dynamic clusters of unsaturated asymmetric lipids can be identified. The clusters show no correlation between leaflets, as observed for the phase domains in mixtures with the symmetric polyunsaturated PCs. Interestingly, we found that asymmetric PC lipids have a preferential orientation such that their saturated tails increase their density toward the periphery of the clusters, facing regions enriched in the fully saturated lipids and cholesterol. The degree of unsaturation increases the cluster size and also enhances the anisotropy of the orientation. The surface density of cholesterol follows a gradient that favors its interaction with the saturated tails. Such gradients in composition lead to gradients in order parameters, such as the conformational order and the area of the tails, which increases away from the unsaturated lipid clusters. We compared, in addition, differences in hydrophobic length mismatch between acyl chains of the low-melting and high-melting components, in mixtures containing either symmetric or asymmetric unsaturated lipids.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
American Chemical Society
dc.rights
info:eu-repo/semantics/openAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
Saturated-Unsaturated mixed chain lipids
dc.subject
Non-ideal mixing
dc.subject
Molecular Dynamics
dc.subject
Coarse-grained models
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Otras Ciencias Químicas
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Ciencias Químicas
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CIENCIAS NATURALES Y EXACTAS
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Biofísica
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Ciencias Biológicas
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CIENCIAS NATURALES Y EXACTAS
dc.title
Comparison of Ternary Bilayer Mixtures with Asymmetric or Symmetric Unsaturated Phosphatidylcholine Lipids by Coarse Grained Molecular Dynamics Simulations
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2023-02-26T15:31:24Z
dc.journal.volume
116
dc.journal.number
11
dc.journal.pagination
3525-3537
dc.journal.pais
Estados Unidos
dc.journal.ciudad
Washington
dc.description.fil
Fil: Rosetti, Carla Mariana. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
dc.description.fil
Fil: Pastorino, Claudio. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
dc.journal.title
Journal of Physical Chemistry B
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1021/jp212406u
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