title: Transmembrane cholesterol migration in planar lipid membranes measured with Vibrio cholerae cytolysin as molecular tool.
abstract: The rate of transbilayer movement (flip-flop) of cholesterol was estimated using planar bilayers with defined initial asymmetry, formed by the opposing monolayers technique. Vibrio cholerae cytolysin (VCC) was utilized as a molecular tool for measuring the cholesterol concentration in the cis leaflet of asymmetric bilayers. To quantify cholesterol flip-flop in planar lipid bilayers, a mathematical model was developed. It considers both the lateral diffusion rate of cholesterol within each monolayer and the flip-flop rate. The difference in initial and steady-state cholesterol contents in bilayer leaflets was used as a start point. Assuming the lateral diffusion coefficient to be of 1 x 10(-8) cm(2) s(-1), the characteristic time of cholesterol flip-flop at 25 +/- 2 degrees C was estimated as <10 s.
authors.affiliation: Department of Biophysics and Radiobiology, Federal University of Pernambuco, Recife, Pernambuco, Brazil. kras@ufpe.br
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Krasilnikov
authors.forename: Liliya N
authors.initials: LN
authors.lastname: Yuldasheva
mesh_terms: D002784:Cholesterol / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry*; D008962:Models, Theoretical; D054353:Perforin / Q000737:chemistry*; D014734:Vibrio cholerae / Q000378:metabolism*
chemical_list: D008051:Lipid Bilayers; D008563:Membrane Lipids; D054353:Perforin; D002784:Cholesterol