Quaternary structure of human deoxyhemoglobin from 2HHB atomic coordinates. Each chain was printed separately as a surface and can be used to assemble the final molecule. The hem molecules were removed and can be printed separately (as balls and sticks or surface) and manually inserted and removed from the binding pocket. This is useful to argue the quaternary structure of proteins, as well as protein-ligand interactions.  I made this to use it for teaching Biochemistry and Structural Biology.