Fig. 4.

Arylamides cause defects in β-lactamase protein translocation. Cultures of E. coli were treated with inhibitory concentrations of PMX 10070 and PMX 10072 (25 μg/ml) for the indicated times, and β-lactamase (bla) was detected by Western blotting. Twenty-six amino acids are cleaved from the N terminus of the precursor bla (unprocessed) upon translocation, yielding mature bla in the periplasm (processed). (A) Arylamide treatment causes precursor accumulation due to inefficient translocation. CCCP treatment was used as a positive control. (B) Growth attenuation caused by PMX 10070, PMX 10072, and CCCP treatment is comparable.