Fig. 4.

(A) SDS-PAGE analysis of modified PadR (black triangles) expressed in E. coli strains. (B) PAD activities (μmol min⁻¹ mg⁻¹; data are averages for three experiments) in mutant strains complemented with native padR (pHR) or modified padR genes (pHRM). Cultures were induced or not with 1 mM ferulic acid for 20 min before harvesting and disrupting the cells. B. subtilis 168, wild-type strain; pHT315, 168 ΔpadR mutant transformed with pHT315 (without padR); pHR, 168 ΔpadR mutant complemented with native padR; M15 to M4, 168 ΔpadR mutants complemented with modified padR. These mutants form three groups based on PAD activity compared to that with native padR (pHR).