Covalently Attached Lipid Bilayers on Planar Waveguides for Measuring Protein Binding to Functionalized Membranes

Abstract

Many biologically important signal transduction processes occur at the level of cell membranes. Specialized membrane receptors, such as ligand-gated ion channels (Unwin, 1993) or G-protein coupled receptors (Strader, 1994), specifically recognize ligands and transform this binding event into a corresponding signal. While in the former case extremely sensitive techniques have been developed to observe the opening and closing of single channels upon ligand binding (Rudy and Iverson, 1992), in the latter case the electrical properties of the membrane remain unchanged upon receptor activation. In order to elucidate the molecular events involved for example in G protein signal cascades, radioactive or fluorescent labels have been introduced by complicated and time-consuming experimental procedures (Feder et al. , 1986; Heithier et al. , 1992).