Toll-like receptors (TLRs) are immunoreceptors responsible for the detection of pathogen-derived molecules. Human TLR4 is a membrane protein with an N-terminal extracellular domain and a C-terminal cytosolic domain connected by a single transmembrane a-helix. The sequence of the transmembrane helix is IIGVSVLSVLVVSVVAVLVY. Estimate the thickness of the cell membrane according to structural features of the a-helix. Draw a simple cartoon figure of TLR4 with the a-helix embedded in the membrane and explain why this a-helix is rich of hydrophobic residues. (The cartoon of the a-helix should show the correct length and handedness of the a-helix)