Investigation on native vesicles containing the nicotinic acetylcholine receptor using FTIR-spectroscopy

The ligand gated ion channel nicotinic acetylcholine receptor is responsible for the electrochemical signal transduction in nerve cells and at the motor endplates. In the recent years the structure of the channel has emerged to a resolution of 4.6 ? [J. Mol. Biol. 288 (1999) 765]. We have used ATR–FTIR and SEIRA spectroscopy to investigate the extramembraneous structure of the receptor. The adsorption of nicotinic acetylcholine receptor rich vesicles on the surface of Ag-cluster leads to the detection of high content of helical structure in the extra membranous parts of the receptor. Spectra indicate a beta -sheet structure perpendicular to the crystal plane.