FIG. 7.

The YscU ΔNPTH mutant shows a different cleavage pattern compared to the wild-type protein. The C-terminally Flag-tagged proteins YscU or YscU ΔNPTH were expressed in the yscU-null mutant strain YPIII(pIB75) from plasmids pML13 and pML16, respectively. The cleaved forms of YscU were visualized by ECL Western blot with monoclonal antibodies directed against the Flag epitope. The different forms of YscU indicated in the figure are as follows: the full-length protein YscU (amino acids 1 to 354)_, the C-terminal cleavage product, YscU (amino acids 264 to 354), and the ca 15-kDa C-terminal fragment of the ΔNPTH mutant protein which is indicated with an asterisk. The thinner arrows point to two nonspecific bands that also appear in negative controls with Yersinia strains that do not carry any Flag-tagged YscU constructs. The bacteria were cultured in BHI depleted of calcium at 37°C, with or without 0.4 mM IPTG, as indicated in the figure. Molecular mass markers are shown to the left in kilodaltons.