Single amino acid mutations effect on PerR degradation by LonA. (A) Protein stability of K50A, N61A, R64A, and R67A variants during in vitro degradation assays with LonA. The half-life of each protein variant was calculated from the average of three independent experiments with ±1 SEM. All PerR variants were purified without H2O2-treatment. (B) Important residues for LonA degradation (N61, green; R67, blue) are indicated on helix 4 of PerR, based on the protein structures PDB ID code 2RGV.