Figure 1.

α-Casein trap experiment to determine whether ClpP recognizes ClpA–RepA complexes. [³H]RepA–ClpA complexes were formed by incubating 28 pmol of ClpA with 18 pmol of [³H]RepA in 40 μl of buffer A containing 0.5 mM ATP[γ-S] for 10 min at 23°C. Reaction volumes were adjusted with 80 μl of buffer A containing 100 μM α-casein, 9 pmol of ClpP, and 2 mM ATP. After a 5-min incubation at 23°C, TCA was added to 20% concentration, and RepA degradation was quantitated by measuring radioactivity in the acid-soluble fractions. Control experiments with added or omitted components in the two steps are as indicated.