Solubilization of Binary Lipid Mixtures by the Detergent Triton X-100: the Role of Cholesterol

dc.contributor.authorMattei, Bruno [UNIFESP]
dc.contributor.authorFranca, Ana D. C. [UNIFESP]
dc.contributor.authorRiske, Karin A. [UNIFESP]
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.description.abstractThe solubilization of lipid bilayers of different composition and phase by the detergent Triton X-100 (Triton X-100) was investigated using optical and fluorescence microscopy of giant unilamellar vesicles (GUVs) and light scattering of large unilamellar vesicles (LUVs). the compositions explored were 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), in the liquid-disordered (Ld) phase, sphingomyelin (SM), in the gel phase, and binary mixtures of these phospholipids with 30 mol % cholesterol (chol), resulting in bilayers in the Ld and liquid-ordered (Lo) phases, respectively. We show that the phospholipid bilayers are completely soluble in TX-100, but optical microscopy reveals that whereas fluid POPC is gradually solubilized by TX-100, gel SM is first shattered in bilayer fragments. Incorporation of TX-100 in the membrane leads to increase in GUV area, which was quantified and expressed as bound detergent-to-lipid molar ratio. the partition of TX-100 in POPC is very high, decreases in POPC/chol, and is negligible in SM/chol. Fluorescence microscopy shows that TX-100 induces Lo/Ld phase separation in previously homogeneous POPC/chol GUVs, and insoluble bilayer fragments/vesicles are detected with optical microscopy and light scattering. Vesicles of SM/chol, in the Lo phase, are virtually insoluble in TX-100. Taken together, our results show that the presence of cholesterol is the origin of membrane resistance to solubilization, which depending on the specific lipid mixture can result in either partially (POPC/chol) or completely (SM/chol) insoluble mixtures.en
dc.description.affiliationUniversidade Federal de São Paulo, Dept Biofis, São Paulo, Brazil
dc.description.affiliationUnifespUniversidade Federal de São Paulo, Dept Biofis, São Paulo, Brazil
dc.description.provenanceMade available in DSpace on 2016-01-24T14:39:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-13en
dc.description.sourceWeb of Science
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description.sponsorshipCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
dc.identifier.citationLangmuir. Washington: Amer Chemical Soc, v. 31, n. 1, p. 378-386, 2015.
dc.publisherAmer Chemical Soc
dc.rightsAcesso restrito
dc.titleSolubilization of Binary Lipid Mixtures by the Detergent Triton X-100: the Role of Cholesterolen