title: Free Brownian motion of individual lipid molecules in biomembranes.
abstract: The mobility of phospholipids in free-standing and supported membranes was investigated on the level of individual molecules. For the analysis of trajectories a new statistical treatment was developed that permitted us to clearly distinguish different types of diffusional motion. A freely diffusing subfraction of lipids within supported membranes was identified. Its mobility was characterized by a mean lateral diffusion constant of D(supp) = 4.6 microm(2)/s. In comparison, the mobility of lipids embedded in "free-standing" planar membranes yielded an increase in the mean diffusion constant by a factor of 4.5, D(free) = 20.6 microm(2)/s. This increase is attributed to the ultrathin (<or=1 nm) lubricating water layer between membranes and glass support.
authors.affiliation: Institute for Biophysics, University of Linz, Linz, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Sonnleitner
authors.forename: G J
authors.initials: GJ
authors.lastname: Schütz
authors.forename: T
authors.initials: T
authors.lastname: Schmidt
mesh_terms: D002462:Cell Membrane / Q000378:metabolism*; D004058:Diffusion; D008954:Models, Biological; D009068:Movement; D010743:Phospholipids / Q000378:metabolism*
chemical_list: D010743:Phospholipids