Figure 3.

Protease sensitivity of GLuc and PhoA. (A) Culture supernatant samples from four different genome-reduced B. subtilis strains, producing either GLuc or PhoA, were incubated without addition (native samples) or with exoprotease-containing culture supernatant of the reference strain TS10. Subsequently, proteins in the samples were separated by LDS-PAGE and GLuc or PhoA were visualized by Western blotting using specific antibodies. The samples were normalized for the OD₆₀₀ values of the respective strains. The respective arrows indicate the expected molecular size of mature GLuc and PhoA in kDa. (B) Western blot of PhoA secreted by the TS10 strain upon growth in a medium supplemented with protease inhibitors. (C) Western blot of culture supernatant samples of B. subtilis IIG-Bs27-39 expressing GLuc after incubation with culture supernatant samples of the protease-deleted B. subtilis 168 derivatives BRB01–BRB08, the TS10 reference strain (positive control), or fresh LB medium (negative control).