Accumulation of a precursor of subunit S1 of pertussis toxin in cell envelopes of Bordetella pertussis in response to the membrane perturbant phenethyl alcohol

Exponential cultures of Bordetella pertussis strain 18334 were treated with the membrane-perturbing agent phenethyl alcohol which, at a concentration of 0.075% v/v, blocked the synthesis of mature subunit S1 of pertussis toxin as revealed by Western blotting. It also caused the accumulation of a precursor, pS1, with an estimated mol. wt of 32 × 103, that was located in the cytoplasmic membrane. These findings suggested that subunit S1 of pertussis toxin was exported in a signal peptidedependent manner.