X-ray Crystal Structure of Rhodopsin

    Figure 7a, below, shows the X-ray crystal structure of rhodopsin, which was recently published.  Figure 7 on the main tutorial page is based on a theoretical model.  Theoretical models for rhodopsin structure have existed for some time, but an actual crystal structure was not available because rhodopsin crystals are extremely difficult to obtain.  Tetsuji Okada worked for two years in a dark room at 4oC to obtain crystals of high enough quality to make x-ray crystallography possible.  (Light causes the crystals to fall apart, as explained in Figure 8 and the text below Figure 8.)

Figure 7a

This figure shows shows the X-ray crystal structure of rhodopsin.  The seven transmembrane alpha-helices are each shown in a different color.  Loops connecting the transmembrane portions of the protein are shown in gray. 

Note: To view this molecule interactively, please use Jmol, and click on the button above.

    Note that although we now have a published crystal structure for rhodopsin, we must still rely on theoretical models of bathorhodopsin. Its very short lifespan (it only exists for a few nanoseconds) will make obtaining a crystal structure for bathorhodopsin even more challenging.