b₂-Adrenergic Receptor: PDB 2RH1

This structure of  the human b₂-Adrenergic G Protein-Coupled Receptor, genetically engineered with a lysozyme insert, was solved by V. Cherezov, D. M. Rosenbaum, M. A. Hanson, S. G. F. Rasmussen, F. S. Thian, T. S. Kobilka, H.- J. Choi, P. Kuhn, W. I  Weis, B. K. Kobilka, & R. C. Stevens in 2007. 

Suggested display options:

Use the right mouse button to display as cartoon and color chain.
Then in the command line type in select 1002-1161, enter, and with the mouse select change color to magenta. Residues 1002-1161 (now magenta) are the protein lysozyme, which was genetically engineered into one of the extracellular loops of the receptor to facilitate crystallization. The b2-adrenergic receptor (GPCR) is blue.

Use the left mouse button to drag the image.
Note the 7 transmembrane a-helices, their tilt and breaks in the helices.

You can use the mouse to select residue CAU and display as spacefill with color CPK.
CAU is the code for carazolol, an inverse agonist whose location defines the binding site for adrenergic ligands on what would be the outer surface of the plasma membrane.
Note how the ligand binding site is in a pocket at one end of the protein, facing the extracellular space.
Also view after you select protein and display as spacefill.

Similarly you can use the mouse to select residue PLM and display as spacefill with color CPK.
PLM is the code for palmitic acid, a covalently attached lipid anchor .
If you use the command line to select cys341 and then select color CPK, you can see that the fatty acid is attached via a thioester linkage.

Now select residue CLR, and display as sticks with color CPK.
CLR cholesterol, is a membrane constituent known to interact with the transmembrane domain.
Other ligands present include: 12P dodecaethylene glycol, ACM acetamide, BU1 1,4-butanediol, MAL maltose, SO4 sulfate ion.

Question:
How does the structure of the transmembrane domain compare to that of rhodopsin?

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