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 hydropathy 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?

Question

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 hydropathy 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?
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 hydropathy 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?

Quizplus · Accepted Answer

As suggested by the presence of four positive hydropathy peaks in the plot (three between residues 200 and 300, and one at the C-terminus), there are four transmembrane helices in each subunit.

The Nicotinic Acetylcholine Receptor Is a Cation Channel in the Plasma