FIG. 2.
Processing of VirB1 and secretion of VirB1*. Strains A348 and PC1001 (ΔvirB1) carrying pTrc200 (pTrc), pTrcB1 (VirB1), or pTrcB1E→A (VirB1E→A) were cultivated under virulence gene-inducing (+AS) or noninducing conditions (−AS). IPTG was added to cultures carrying pTrc200 constructs for induction of gene expression from the trc promoter. Cell lysates (A) and secreted proteins precipitated from the supernatant (B) were separated by SDS-PAGE followed by Western blotting with A. tumefaciens C58 VirB1-specific antiserum. Arrows indicate VirB1 and its C-terminal processing product VirB1*. A VirB1* processing product of strain A348 VirB1 was not detected with strain C58 VirB1-specific antiserum. Numbers on the right indicate reference proteins.