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dc.contributor.authorLucio, Aline D.
dc.contributor.authorVequi-Suplicy, Cintia C.
dc.contributor.authorFernandez, Roberto M. [UNESP]
dc.contributor.authorLamy, M. Teresa
dc.identifier.citationJournal of Fluorescence. New York: Springer/plenum Publishers, v. 20, n. 2, p. 473-482, 2010.
dc.description.abstractThe highly hydrophobic fluorophore Laurdan (6-dodecanoyl-2-(dimethylaminonaphthalene)) has been widely used as a fluorescent probe to monitor lipid membranes. Actually, it monitors the structure and polarity of the bilayer surface, where its fluorescent moiety is supposed to reside. The present paper discusses the high sensitivity of Laurdan fluorescence through the decomposition of its emission spectrum into two Gaussian bands, which correspond to emissions from two different excited states, one more solvent relaxed than the other. It will be shown that the analysis of the area fraction of each band is more sensitive to bilayer structural changes than the largely used parameter called Generalized Polarization, possibly because the latter does not completely separate the fluorescence emission from the two different excited states of Laurdan. Moreover, it will be shown that this decomposition should be done with the spectrum as a function of energy, and not wavelength. Due to the presence of the two emission bands in Laurdan spectrum, fluorescence anisotropy should be measured around 480 nm, to be able to monitor the fluorescence emission from one excited state only, the solvent relaxed state. Laurdan will be used to monitor the complex structure of the anionic phospholipid DMPG (dimyristoyl phosphatidylglycerol) at different ionic strengths, and the alterations caused on gel and fluid membranes due to the interaction of cationic peptides and cholesterol. Analyzing both the emission spectrum decomposition and anisotropy it was possible to distinguish between effects on the packing and on the hydration of the lipid membrane surface. It could be clearly detected that a more potent analog of the melanotropic hormone alpha-MSH (Ac-Ser(1)-Tyr(2)-Ser(3)-Met(4)-Glu(5)-His(6)-Phe(7)-Arg(8)-Trp(9)-Gly(10)-Lys(11)-Pro(12)-Val(13)-NH(2)) was more effective in rigidifying the bilayer surface of fluid membranes than the hormone, though the hormone significantly decreases the bilayer surface hydration.en
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.publisherSpringer/plenum Publishers
dc.relation.ispartofJournal of Fluorescence
dc.sourceWeb of Science
dc.subjectSpectrum decompositionen
dc.subjectFluorescence anisotropyen
dc.subjectMelanocortin peptidesen
dc.subject[Nle(4), D-Phe(7)]alpha-MSHen
dc.titleLaurdan Spectrum Decomposition as a Tool for the Analysis of Surface Bilayer Structure and Polarity: a Study with DMPG, Peptides and Cholesterolen
dcterms.rightsHolderSpringer/plenum Publishers
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversidade Federal de Lavras (UFLA)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.description.affiliationUniv São Paulo, Inst Fis, BR-05314970 São Paulo, Brazil
dc.description.affiliationUniversidade Federal de Lavras (UFLA), Dept Exatas, BR-37200000 Lavras, MG, Brazil
dc.description.affiliationUniv Estadual Paulista, Dept Fis & Biofis, Inst Biociencias, BR-18618000 Botucatu, SP, Brazil
dc.description.affiliationUnespUniv Estadual Paulista, Dept Fis & Biofis, Inst Biociencias, BR-18618000 Botucatu, SP, Brazil
dc.rights.accessRightsAcesso restrito
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Biociências, Botucatupt
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