Free Brownian motion of individual lipid molecules in biomembranes.
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.
Sonnleitner
A
A
Institute for Biophysics, University of Linz, Linz, Austria.
Schütz
G J
GJ
Schmidt
T
T
D002462:Cell Membrane / Q000378:metabolism*; D004058:Diffusion; D008954:Models, Biological; D009068:Movement; D010743:Phospholipids / Q000378:metabolism*
D010743:Phospholipids