Figure 4: Substoichiometric amounts of ADEP cause partial inhibition of ClpP.
From: AAA+ chaperones and acyldepsipeptides activate the ClpP protease via conformational control
(a) Concentration-dependent partial inhibition or stimulation of wild-type SaClpP peptidase activity by ADEP7. The ratio of ADEP bound to ClpP was estimated from the concentrations at the minimum and a Kd of 2.1 μM. A ratio of 0.2–0.3 corresponds to 2.8–4.2 ADEP molecules per SaClpP14. (b) Concentration-dependent inhibition or stimulation of SaClpP-D172N peptidase activity by ADEP7. In line with the compressed conformation of SaClpP-D172N, the initial peptidase activity is lower than that of the wild-type protein. The ratio of ADEP bound to ClpP was estimated from a Kd of 6.1 μM. (c) FITC–casein degradation by SaClpP-D172N indicates positive cooperativity (h=2.8±0.3; EC50=4.3±0.2 μM). (d) Analytical ultracentrifugation results of SaClpP (7.5 μM) treated with DMSO (0.6% (v/v)) or ADEP7 (2, 7.5 and 15 μM). (e) Analytical ultracentrifugation results of SaClpP-D172N (7.5 μM) treated with DMSO (0.6% (v/v)) or ADEP7 (7.5 and 15 μM). Plotted data in a–c are mean±s.d. (N=3). Parameters determined from curve fits in c are given with fitting errors.
