Incorporation and antibody recognition of a lipid-anchored membrane protein in supported lipid layers

The formation of supported lipid layers incorporating promastigote surface protease (PSP), a glycosylphosphatidylinositol-anchored protein, is investigated using surface plasmon resonance, Both hydrophilic and hydrophobic substrates are used for the formation of lipid layers, and results are consistent with the formation of lipid bilayers and monolayers, respectively. Specific antibody binding to layers containing PSP is observed, whereas nonspecific binding of the antibody to the surface is effectively suppressed by the phosphatidylcholine lipid layer, Phosphatidylinositol-specific phospholipase C is used to remove the lipid moieties from the membrane-incorporated PSP, releasing it into solution in a hydrophilic form and demonstrating that a large fraction of the protein is anchored in the lipid layer via the lipid moieties. (C) 1997 Academic Press.