Influence of salt on the structure of DMPG studied by SAXS and optical microscopy

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dc.contributor.authorFernandez, Roberto Morato
dc.contributor.authorRiske, Karin do Amaral [UNIFESP]
dc.contributor.authorAmaral, Lia Queiroz do
dc.contributor.authorItri, Rosangela
dc.contributor.authorLamy, Maria Teresa Moura
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.date.accessioned2016-01-24T13:49:40Z
dc.date.available2016-01-24T13:49:40Z
dc.date.issued2008-04-01
dc.description.abstractAqueous dispersions of 50 mM dimyristoylphosphatidylglycerol (DMPG) in the presence of increasing salt concentrations (2-500 mM NaCl) were studied by small angle X-ray scattering (SAXS) and optical microscopy between 15 and 35 degrees C. SAXS data show the presence of a broad peak around q similar to 0.12 angstrom(-1) at all temperatures and conditions, arising from the electron density contrasts within the bilayer. Up to 100 mM NaCl, this broad peak is the main feature observed in the gel and fluid phases. At higher ionic strength (250-500 mM NaCl), an incipient lamellar repeat distance around d= 90-100 angstrom is detected superimposed to the bilayer form factor. the data with high salt were fit and showed that the emergent Bragg peak is due to loose multilamellar structures, with the local order vanishing after similar to 4d. Optical microscopy revealed that up to 20 mM NaCl, DMPG is arranged in submicroscopic vesicles. Giant (loose) multilamellar vesicles (MLVs) start to appear with 50 mM NaCl, although most lipids are arranged in small vesicles. As the ionic strength increases, more and denser MLVs are seen, up to 500 mM NaCl, when MLVs are the prevailing structure. the DLVO theory could account for the experimentally found interbilayer distances. (c) 2007 Elsevier B.V. All rights reserved.en
dc.description.affiliationUniversidade Federal de São Paulo, Inst Fis, BR-05315970 São Paulo, Brazil
dc.description.affiliationUnifespUniversidade Federal de São Paulo, Escola Paulista de Medicina (EPM)
dc.description.sourceWeb of Science
dc.format.extent907-916
dc.identifierhttp://dx.doi.org/10.1016/j.bbamem.2007.12.005
dc.identifier.citationBiochimica Et Biophysica Acta-biomembranes. Amsterdam: Elsevier B.V., v. 1778, n. 4, p. 907-916, 2008.
dc.identifier.doi10.1016/j.bbamem.2007.12.005
dc.identifier.fileWOS000255228000011.pdf
dc.identifier.issn0005-2736
dc.identifier.urihttp://repositorio.unifesp.br/handle/11600/30535
dc.identifier.wosWOS:000255228000011
dc.language.isoeng
dc.publisherElsevier B.V.
dc.relation.ispartofBiochimica Et Biophysica Acta-biomembranes
dc.rightsinfo:eu-repo/semantics/openAccess
dc.rights.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dc.subjectgel-fluid phase transitionen
dc.subjectintermediate phaseen
dc.subjectcharged phospholipiden
dc.subjectDLVO theoryen
dc.titleInfluence of salt on the structure of DMPG studied by SAXS and optical microscopyen
dc.typeinfo:eu-repo/semantics/article
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