Abstract
Quantitative understanding and control of phospholipid dynamics in biological membranes is an important issue in biophysics and cell biology, but handling biological membranes as multicomponent, heterogeneous, and complex systems is not a straightforward task. On the other hand, the use of artificial lipid bilayers (vesicles) as a simplified model of biomembranes allows physicochemical measurements and quantitative discussions since their lipid composition and membrane curvature can be manipulated flexibly. We have established a method for evaluating lipid dynamics in phospholipid vesicle systems by time–resolved small–angle neutron scattering. This method exploits the fact that the scattering length densities of normal (protiated) and deuterated lipids differ significantly, and that the neutron scattering intensity decreases when these lipids are exchanged between vesicles. This review will present the evaluation of the kinetics of spontaneous and protein–mediated phospholipid transfers between vesicles and describe the mechanisms by which increased membrane curvature facilitates these processes.
