This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Parker, A. Articles by Huang, J. Search for Related Content PubMed PubMed Citation Articles by Parker, A. Articles by Huang, J.

Lateral Distribution of Cholesterol in Dioleoylphosphatidylcholine Lipid Bilayers: Cholesterol-Phospholipid Interactions at High Cholesterol Limit

Department of Physics, Texas Tech University, Lubbock, Texas 79409

Correspondence: Address reprint requests to Dr. Juyang Huang, Dept. of Physics, Texas Tech University, Lubbock, TX 79409. Tel: 806-742-4780; Fax: 806-742-1182; E-mail: juyang.huang{at}ttu.edu.

Lateral organization of cholesterol in dioleoyl-phosphatidylcholine (DOPC) lipid bilayers at high cholesterol concentration (>45 mol%) was investigated using steady-state fluorescence anisotropy and fluorescent resonance energy transfer techniques. The recently devised Low Temperature Trap method was used to prepare compositionally uniform cholesterol/DOPC liposomes to avoid the problem of lipid demixing. The fluorescence anisotropy of diphenylhexatrience chain-labeled phosphatidylcholine (DPH-PC) in these liposomes exhibited local maxima at cholesterol mol fractions of 0.50 and 0.57, and a sharp drop at 0.67. For the liposomes labeled with both dehydroergosterol and DPH-PC, the fluorescent resonance energy transfer efficiency from dehydroergosterol to DPH-PC displayed a steep jump at cholesterol mol fraction of 0.5, and dips at 0.57 and 0.68. These results indicate the presence of highly ordered cholesterol regular distribution domains at those observed critical compositions. The observed critical mol fraction at 0.67 agreed favorably with the solubility limit of cholesterol in DOPC bilayers as independently measured by light scattering and optical microscopy. The regular distribution at 0.57 was previously predicted from a Monte Carlo simulation based on the Umbrella model. The results strongly support the hypothesis that the primary requirement for cholesterol-phospholipid mixing is that the polar phospholipid headgroups need to cover the nonpolar body of cholesterol to avoid the exposure of cholesterol to water.

This article has been cited by other articles:

				G. P. Holland and T. M. Alam Unique Backbone-Water Interaction Detected in Sphingomyelin Bilayers with 1H/31P and 1H/13C HETCOR MAS NMR Spectroscopy Biophys. J., August 1, 2008; 95(3): 1189 - 1198. [Abstract] [Full Text] [PDF]

				C. S. Helrich, J. A. Schmucker, and D. J. Woodbury Evidence that Nystatin Channels Form at the Boundaries, Not the Interiors of Lipid Domains Biophys. J., August 1, 2006; 91(3): 1116 - 1127. [Abstract] [Full Text] [PDF]

				T. Starke-Peterkovic, N. Turner, M. F. Vitha, M. P. Waller, D. E. Hibbs, and R. J. Clarke Cholesterol Effect on the Dipole Potential of Lipid Membranes Biophys. J., June 1, 2006; 90(11): 4060 - 4070. [Abstract] [Full Text] [PDF]

				S. A. Pandit, S. Vasudevan, S. W. Chiu, R. J. Mashl, E. Jakobsson, and H. L. Scott Sphingomyelin-Cholesterol Domains in Phospholipid Membranes: Atomistic Simulation Biophys. J., August 1, 2004; 87(2): 1092 - 1100. [Abstract] [Full Text] [PDF]