The nicotinic acetylcholine receptor is a cation channel in

The nicotinic acetylcholine receptor is a cation channel in the plasma membrane of some neurons. It is composed of five subunits, each of which is a transmembrane protein. The hydropath plot for each mature subunit is qualitatively represented in the following diagram. How many membrane-spanning alpha helices do you expect to exist in each subunit? ALSO, indicate these transmembrane passes by shading in the hydropathic regions in the graph below.

Solution

The ion flux through the nAChR shows the residues of the transmembrane segment or M2 which forms the channel lining structure of the receptor. The five subunits each contributes its M2 to form a five fold symmetry. The M2 usede to line pore because this segment form an amphipathic alpha helix. So there are 5 M2 segment and each have an alpha helix. Therefore there were total 5 alpha helical structure present in the protein.