TY - JOUR
T1 - Raft-like domain formation in large unilamellar vesicles probed by the fluorescent phospholipid analogue, C12NBD-PC
AU - Coste, V
AU - Puff, N
AU - Lockau, D
AU - Quinn, P J
AU - Angelova, M I
PY - 2006/4
Y1 - 2006/4
N2 - The liquid-ordered/disordered-phase domain co-existence in large unilamellar vesicle membranes consisting of phosphatidylcholine: sphingomyelin (2: 1) with different amounts of cholesterol has been examined using a concentration-dependent self-quenching of a single reporter molecule, C12NBD-PC. A temperature-dependent decrease of fluorescence intensity was associated with the expected formation and increase of 1(o)-phase membrane fraction in the vesicles. The result is consistent with exclusion of the fluorescent probe from the liquid-ordered phase which partitions preferentially into the liquid-disordered phase membrane domains. This leads to an increase of the local concentration of fluorophore in the liquid-disordered phase and a decrease of the quantum yield. This effect was used to obtain a quantitative estimation of the fraction of the vesicle membrane occupied by the liquid-ordered phase, Phi(o), as a function of temperature and cholesterol content between 0 and 45 mol%. The value of Phi(o) was related to the assumed partition coefficient k(p) of probe between liquid-ordered/disordered phases. For large unilamellar vesicles containing 20 and 4 mol% cholesterol and probe, respectively, with k(p) = 0 (probe completely excluded from liquid-ordered phase), Phi(o) = 0.16 and with k(p)=0.2, Phi(o)=0.2. The results are relevant to the action of detergent in the fractionation of detergent-resistant membrane from living cells. (c) 2006 Elsevier B.V. All rights reserved
AB - The liquid-ordered/disordered-phase domain co-existence in large unilamellar vesicle membranes consisting of phosphatidylcholine: sphingomyelin (2: 1) with different amounts of cholesterol has been examined using a concentration-dependent self-quenching of a single reporter molecule, C12NBD-PC. A temperature-dependent decrease of fluorescence intensity was associated with the expected formation and increase of 1(o)-phase membrane fraction in the vesicles. The result is consistent with exclusion of the fluorescent probe from the liquid-ordered phase which partitions preferentially into the liquid-disordered phase membrane domains. This leads to an increase of the local concentration of fluorophore in the liquid-disordered phase and a decrease of the quantum yield. This effect was used to obtain a quantitative estimation of the fraction of the vesicle membrane occupied by the liquid-ordered phase, Phi(o), as a function of temperature and cholesterol content between 0 and 45 mol%. The value of Phi(o) was related to the assumed partition coefficient k(p) of probe between liquid-ordered/disordered phases. For large unilamellar vesicles containing 20 and 4 mol% cholesterol and probe, respectively, with k(p) = 0 (probe completely excluded from liquid-ordered phase), Phi(o) = 0.16 and with k(p)=0.2, Phi(o)=0.2. The results are relevant to the action of detergent in the fractionation of detergent-resistant membrane from living cells. (c) 2006 Elsevier B.V. All rights reserved
U2 - 10.1016/j.bbamem.2006.03.003
DO - 10.1016/j.bbamem.2006.03.003
M3 - Article
VL - 1758
SP - 460
EP - 467
JO - BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES
JF - BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES
IS - 4
ER -