FIG. 2.
Induction of PnisA::pep fusions. Strains UKLc11-C (PepC), UKLc11-I (PepI), and UKLc11-Q (PepQ), carrying the nisRK genes integrated into the chromosomal leuB locus and the respective PnisA::pep fusions integrated into the sex factor, were grown in GM17. At an OD600 of 0.5 U, pepI expression was induced by adding nisin to a final concentration of 3 ng/ml. Cell extracts prepared from culture aliquots at 0, 40, and 120 min after induction were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis on 12% polyacrylamide gels. Arrowheads indicate the expected gel positions of individual peptidases. The molecular masses of protein markers (M) (in kilodaltons) are given on the left.