Drug interactions with the ribosome, and the conformational changes associated with drug binding. Panels (a), (c), and (e) show how tiamulin, homoharringtonine, and bruceantin interact with the ribosome. Drugs are shown with C gold, N blue, O red, and S green. Water molecules are shown as red balls and hydrogen bonds are shown as red dashes. Panels (b), (d), and (f) show the conformational changes associated with drug binding. The drugs are color coded as just described. The drug-bound conformation of surrounding bases is shown in cyan, superimposed on the apo- conformation (gray).