| Abstract | The regulatory ATPase ClpX in Bacillus anthracis contributes to resistance against cell-wall active antibiotics. ClpX can function independently as a chaperone or together with ClpP to form the ClpXP protease. It is unclear whether ClpX-mediated antibiotic resistance in B. anthracis is dependent on ClpP and, if so, which of the two clpP genes found in B. anthracis is important in antibiotic resistance. To do this, we created a strain of B. anthracis Sterne that is unable to form the ClpXP protease and found increased susceptibility to cell envelope-targeting antibiotics, suggesting that ClpX-mediated antibiotic resistance is dependent on ClpP. Then, we constructed insertional mutants in each of the two clpP genes, ¿clpP#1 and ¿clpP#2, and found significantly increased susceptibility to cell-envelope active antibiotics in both the clpP insertional mutants. However, neither ¿clpP#1 nor ¿clpP#2 showed as strong a phenotype as ¿clpX, suggesting that the two ClpPs can partially compensate for each other. |
