title: Synthetic lipid-anchored receptors based on the binding site of a monoclonal antibody.
abstract: Highly specific ligand receptor interactions generally characterize molecular recognition at cell surfaces and other biological systems. In this study we simulate a membrane receptor by fusing a monoclonal antibody fragment to a phospholipid. A sulfhydryl group in the hinge region of a monoclonal antibody fragment, was covalently linked to derivatives of phosphatidylethanolamines and phosphatidylserine via three different hydrophilic spacer arms. We investigated and characterized these lipid-anchored Fab-fragments which we have named 'Fab-lipids' in liposomal and monolayer systems. Methods for the monomolecular assembling of such films at the air/water interface and techniques used for their manipulation are outlined. We describe two possibilities for building a monomolecular receptor layer, consisting of two-dimensional pattern of oriented Fab-fragments with their artificial hydrophobic anchor embedded in a lipid matrix. In the first method a monomolecular film at the air/water interface was allowed to form from a vesicular suspension and driven into a phase separation, resulting in protein rich domains embedded in a protein depleted phase. This film was transferred onto a solid support in such a way that the established pattern was preserved. Alternatively, a recognition pattern was formed by directly cross-linking the Fab-fragments to preformed planar membranes composed of the reactive spacer-lipids and an inert matrix lipid. Specificity as well as contrast of the binding activity of the receptor layers were qualified using micro-fluorimetry.
authors.affiliation: Physik Department, Biophysik, TU München, Garching, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Egger
authors.forename: S P
authors.initials: SP
authors.lastname: Heyn
authors.forename: H E
authors.initials: HE
authors.lastname: Gaub
mesh_terms: D019297:2,4-Dinitrophenol; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D001666:Binding Sites, Antibody / Q000378:metabolism*; D002152:Calorimetry, Differential Scanning; D002460:Cell Line; D004140:Dinitrophenols / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005456:Fluorescent Dyes / Q000378:metabolism; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism; D050356:Lipid Metabolism; D008081:Liposomes / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010743:Phospholipids / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D004140:Dinitrophenols; D005456:Fluorescent Dyes; D007140:Immunoglobulin Fab Fragments; D008081:Liposomes; D010743:Phospholipids; D011956:Receptors, Cell Surface; D019297:2,4-Dinitrophenol