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Bilayer polarity and its thermal dependency in the e(o) and e(d) phases of binary phosphatidylcholine/cholesterol mixtures

2007-11Journal article Open access
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dc.contributor.authorArrais, Dalila
dc.contributor.authorMartins, Jorge
dc.date.accessioned2018-12-07T14:58:00Z
dc.date.available2018-12-07T14:58:00Z
dc.date.issued2007-11
dc.description.abstractDiverse variations in membrane properties are observed in binary phosphatidylcholine/cholesterol mixtures. These mixtures are nonideal, displaying single or phase coexistence, depending on chemical composition and other thermodynamic parameters. When compared with pure phospholipid bilayers, there are changes in water permeability, bilayer thickness and thermomechanical properties, molecular packing and conformational freedom of phospholipid acyl chains, in internal dipolar potential and in lipid lateral diffusion. Based on the phase diagrams for DMPC/cholesterol and DPPC/cholesterol, we compare the equivalent polarity of pure bilayers with specific compositions of these mixtures, by using the Py empirical scale of polarity. Besides the contrast between pure and mixed lipid bilayers, we find that liquid-ordered and liquid-disordered (e(d)) phases display significantly different polarities. Moreover, in the e(o) phase, the polarities of bilayers and their thermal dependences vary with the chemical composition, showing noteworthy differences for cholesterol proportions at 35, 40, and 45 mol%. At 20 degrees C, for DMPC/ cholesterol at 35 and 45 mol%, the equivalent dielectric constants are 21.8 and 23.8, respectively. Additionally, we illustrate potential implications of polarity in various membrane-based processes and reactions, proposing that for cholesterol containing bilayers, it may also go along with the occurrence of lateral heterogeneity in biological membranes. (c) 2007 Elsevier B.V. All rights reserved.
dc.description.versioninfo:eu-repo/semantics/publishedVersion
dc.identifier.doi10.1016/j.bbamem.2007.08.012
dc.identifier.issn0005-2736
dc.identifier.urihttp://hdl.handle.net/10400.1/11810
dc.language.isoeng
dc.peerreviewedyes
dc.publisherElsevier
dc.relationStructure, Tropisms and Molecular Dynamics of the Stratum Corneum Lipid Matrix. A Study in Model Systems
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
dc.subjectNuclear-Magnetic-Resonance
dc.subjectLipid-bilayers
dc.subjectPyrene fluorescence
dc.subjectSolvent polarities
dc.subjectWater-penetration
dc.subjectLateral diffusion
dc.subjectAromatic-hydrocarbons
dc.subjectPhospholipid-bilayers
dc.subjectMaximum solubility
dc.subjectAtpase activity
dc.titleBilayer polarity and its thermal dependency in the e(o) and e(d) phases of binary phosphatidylcholine/cholesterol mixtures
dc.typejournal article
dspace.entity.typePublication
oaire.awardTitleStructure, Tropisms and Molecular Dynamics of the Stratum Corneum Lipid Matrix. A Study in Model Systems
oaire.awardURIinfo:eu-repo/grantAgreement/FCT/POCI/POCTI%2FQUI%2F45090%2F2002/PT
oaire.citation.endPage2922
oaire.citation.issue11
oaire.citation.startPage2914
oaire.citation.titleBiochimica et Biophysica Acta-Biomembranes
oaire.citation.volume1768
oaire.fundingStreamPOCI
person.familyNameArrais
person.familyNameMartins
person.givenNameDalila
person.givenNameJorge
person.identifier.ciencia-id8516-F285-FB5D
person.identifier.orcid0000-0003-2356-5971
person.identifier.orcid0000-0001-5460-1969
person.identifier.ridM-6234-2013
person.identifier.scopus-author-id7201798828
project.funder.identifierhttp://doi.org/10.13039/501100001871
project.funder.nameFundação para a Ciência e a Tecnologia
rcaap.rightsrestrictedAccess
rcaap.typearticle
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relation.isAuthorOfPublication1671e2f3-b61c-426e-8d31-0ebb770673ad
relation.isAuthorOfPublication.latestForDiscoverya5bc4be9-f4cf-4529-acc1-ef7c56601493
relation.isProjectOfPublication06c083e7-d839-4a90-893f-aa9a68aec028
relation.isProjectOfPublication.latestForDiscovery06c083e7-d839-4a90-893f-aa9a68aec028

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