Figure 4.

Unfolding and trapping of RepGFP by ClpA. (A) RepGFP was incubated with ClpA in the presence of 2 mM ATP and an ATP-regenerating system (red triangles) in unfolding assays as described in the text. ADP (10 mM) was added to a reaction mixture that had been incubated for 9 min with ATP (black open squares). α-Casein (40 μM) was added to another reaction mixture that had been incubated with ATP for 9 min (green circles). Fluorescence was measured at the times indicated. (B) RepGFP was incubated with ClpA in the presence of 2 mM ATP and an ATP-regenerating system (red triangles) as in A. After 9 min of incubation with ATP, either 10 mM ATP[γS] (blue squares) or 10 mM ATP[γS] and 40 μM α-casein (open black circles) were added to the reaction mixtures. Fluorescence was measured with time at 25°C and the initial fluorescence was set equal to 1.