Figure 3. The Hsp90_Ec mutant proteins exhibit defective chaperone activity in vitro.

(A) Reactivation of heat-denatured luciferase by Hsp90_Ec wild type or mutants in conjunction with DnaK, CbpA and GrpE (K/A/E) was measured over time. The value obtained with K/A/E alone was subtracted. It was previously shown that only the soluble fraction of the denatured luciferase is reactivated by Hsp90_Ec and the DnaK system and that this soluble fraction corresponds to about 20% of the total luciferase (Genest et al., 2011). Thus Hsp90_Ec wild type in combination with the DnaK system reactivates about 50% of the soluble inactive luciferase in this experiment.

(B) Initial linear rates of luciferase reactivation (red) by Hsp90_Ec wild type or mutants in the presence of K/A/E were calculated from Figure 3A and the rate of wild type reactivation set to 100%. The ATPase activity of Hsp90_Ec wild type or mutants was measured and is represented in blue.

In (A) and (B), data from three replicates are presented as mean ± SEM.

See also Figure S3.