Fig. 3.

The chaperone function of the DnaK system is required for luciferase remodeling in collaboration with Hsp90_Ec. (A) ATP hydrolysis and substrate binding by DnaK are required for luciferase reactivation. Reactivation of heat-denatured luciferase was measured over time as described in Methods in the presence of wild-type DnaK, CbpA, and GrpE (K/A/E) or in reactions containing Hsp90_Ec, CbpA, and GrpE in the presence of wild-type DnaK, DnaK_(N451K), DnaK_(D201N), DnaK_(K70A), or DnaK_(V436F). (B) The activity of the CbpA cochaperone is required for luciferase reactivation. Reactivation of heat-denatured luciferase was measured over time as described in Methods in the presence of wild-type DnaK, CbpA, and GrpE (K/A/E) without or with CbpM; Hsp90_Ec and K/A/E without or with CbpM; or Hsp90_Ec and DnaK, CbpA_(H33Q), and GrpE (K/A_(H33Q)/E). For both panels, data from three replicates are presented as mean ± SEM. Some error bars are covered by plot symbols.