Figure 4.

Initial velocity of ATP hydrolysis by the Glu-409 → Ala and Arg-501 → Ala GroEL mutants and the corresponding double mutant at different ATP concentrations. The data were fitted to the previously derived equation for a three-state nested allosteric model (see Experimental Procedures and ref. 14). The oligomer concentrations of GroEL is 25 nM except for the Arg-501 → Ala mutant, which is 37.5 nM. The reactions were carried out at 25°C as previously described (28).