Surface properties of cholesterol-containing membranes detected by Prodan fluorescence.

EWA K. KRASNOWSKA; LUIS A. BAGATOLLI; E. GRATTON; T. PARASASSI

BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2001 vol. 1511 p. 330 - 330

0005-2736

he fluorescent membrane probe 6-propionyl-2-dimethylaminonaphthalene (Prodan) displays a high sensitivity to the polarity and packing properties of lipid membrane. Contrary to 6-lauroyl-2-dimethylaminonaphthalene (Laurdan), Prodan can also monitor the properties of the membrane surface, i.e., the polar-head pretransition. In bilayers composed of coexisting gel and liquid-crystalline phases, Prodan shows a preferential partitioning in the latter, so that the detected membrane properties mainly belong to fluid domains. In the presence of cholesterol, the packing properties of the gel phase phospholipids are modified in such a way that Prodan can penetrate and label the membrane. Although Prodan labeling of the gel phase is a function of cholesterol concentration, 3 mol percent cholesterol is sufficient for a 60% Prodan labeling with respect to the maximum labeling reached at 15 mol percent cholesterol. We present steady-state and dynamical fluorescence measurements of Prodan in bilayers