Donor-donor energy migration (DDEM) as a tool for studying aggregation in lipid phases.
Spectrochim Acta A Mol Biomol Spectrosc
; 57(9): 1839-45, 2001 Aug.
Article
em En
| MEDLINE
| ID: mdl-11506035
ABSTRACT
A BODIPY-labelled sulfatide (N-(BODIPY-FL-pentanoyl)-galactosylcerebroside-sulfate, hereafter abbreviated as BD-Sulfatide) was solubilised at different concentrations in lipid vesicles of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). Time-correlated single photon counting experiments show that the fluorescence relaxation is mono-exponential (with a lifetime of 6.5 ns) at molar ratios of BD-Sulfatide DOPC that are less than 1100. The fluorescence steady-state anisotropy decreases monotonously at molar ratios smaller than 11000, which is compatible with donor-donor energy migration (DDEM) among the BODIPY groups. A model that assumes DDEM across the lipid bilayers, as well as in their planes, was used to analyse the time-resolved fluorescence anisotropy. Only two parameters appear in the model namely the bilayer thickness (d) and the average number density (C2) distribution of BD-Sulfatide in the lipid bilayers. The extracted d-values vary between 35 and 40 A, which is about the reported thickness of a bilayer of DOPC (38 A). Hence, the BODIPY groups are preferentially located in the water-lipid interface. At low concentration the experimental C2-values and those independently calculated are in good agreement, while the experimental values gradually become lower with increasing BD-Sulfatide concentration. These results are compatible with an aggregation of the sulfatides and self-quenching of BODIPY, which is clearly established at higher concentrations of the BD-Sulfatide.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfatidilcolinas
/
Compostos de Boro
/
Transferência de Energia
/
Bicamadas Lipídicas
Idioma:
En
Revista:
Spectrochim Acta A Mol Biomol Spectrosc
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Suécia