Incorporation of brain membrane proteins into planar bilayer lipid membranes.

Am method is presented which enables the incorporation of solubilized brain membrane proteins into bilayer lipid membranes (BLM) from brain lipids. The digitonin solubilized proteins are first incorporated into liposomes which undergo fusion with the BLM in a second step. The incorporation results in a large increase in membrane conductivity which maintains at a stable level for hours. Identical electrical phenomena were observed after incorporation of the membrane fragments which were used as starting material of protein extraction. The method can be used to reconstitute membrane proteins to the their natural lipid environment in a planar BLM. Our results argue against the essential role of Ca2+ and osmotic gradients during fusion of bilayer structures.