Opening image: GroEL-GroES complex from E. coli. The seven-membered GroEL ring (green) forms a hollow cylinder that is capped at one end by GroES cap (gold). The cap also contains seven subunits. The seven-fold axis of symmetry is in the vertical direction.

Toggle spin. Note the "honeycomb structure," somewhat reminescent of the space frames used in architecture and high-performance sport cars. This framework has the advantage of being light and strong, without using excessively long polypeptide chains for the quaternary structure.

Click here to view from the top.

Click here to move to bottom view. Rock the model back and forth gently. Notice the spacious interior.

Click here to return to side view. All seven members of the GroEL ring are locked in the open conformation with bound ADP molecules. Color the three domains of one GroEL (cpn60) subunit as in the previous section: apical, middle and equatorial.

We now see a cutaway of the cage, with three GroEL subunits removed.

Toggle exposed charged residues (positive, blue; negative, red; neutral, gray).

Dissociation of the GroES lid takes place after ATP binds to the active sites on the companion (empty) GroEL ring (not shown here). Toggle the GroES cap on and off.