This figure displays five small hypothetical proteins The ah

This figure displays five small hypothetical proteins. The a-helix secondary structure of the protein is bracketed and the number of amino acids in the helix is indicated. If the hypothetical ER localization sequence is green-yellow-yellow-green-yellow-red, what protein could potentially be a transmembrane protein in the plasma membrane?

Solution

Protein E

Protein E is more likely to be an integral protein. It has a large number of hydrophobic amino acids at the membrane interface (the thickness of membrane is 10nm) which can fit into the hydrophobic environment of the lipid bilayer. The amino acid sequence flanking on either side of the membrane will be polar since it is aqueous polar environment.