Fig. 4.

Cellular thermal shift assay to verify the interaction of M21 with ClpP. (A) Western blot data from cellular thermal shift assay experiments determining the heat stability of ClpP in bacterial lysate after a 1 h preincubation period in the presence of DMSO. The numbers under each band indicate the temperature in degree Celsius of sample treatment. The shift of denatured temperature of ClpP on treatment with M21 indicated the binding of M21 to the enzyme. The reduced heat sensitivity of mutants of A118G and T146A in the presence of M21 suggested that these amino acid residues should be involved in the binding of M21 on ClpP. (B) M21 showed different effects on urease productions in wild-type and mutants at different concentrations.