FORMATION AND CHARACTERIZATION OF LIPOPEPTIDE LAYERS AT INTERFACES FOR THE MOLECULAR RECOGNITION OF ANTIBODIES

A lipopeptide, carrying the antigenic peptide segment 135 - 154 of VP1 , one of the capsid proteins of the picornavirus which causes foot-and -mouth disease in cattle, was investigated in lipid monolayers on the water surface and on hydrophobic solid supports. Such lipid monolayers , if present in the fluid state, can incorporate the lipopeptide at an y given lipid/lipopeptide ratio. Circular dichroism and infrared spect roscopy show that, on the surface of the lipid layers, the peptidic po rtion of the lipopeptide adopts an average structure similar to that o bserved on the surface of the intact virus. The peptide is fully acces sible to specific antibody binding as revealed by epifluorescence micr oscopy of lipid monolayers on the water surface and by surface plasmon resonance measurements of supported layers. In addition, the lipid mo nolayer surface prevents nonspecific protein binding. Since the lipope ptide-containing Lipid monolayers can easily be fanned by self-assembl y on many transducer surfaces, we believe that this method is of gener al importance for the controlled presentation of antigens for the subs equent detection of antibody binding. More importantly, the findings o pen the way for simulating ligand-receptor interactions on biological cell surfaces in a reconstituted system using modern surface sensitive techniques which are equally interesting For basic research and biose nsor applications.