FIG. 4.

Complex formation of VirB7 and VirB9 in cell lysates wild-type strain C58 (lanes 1) and virB6 deletion strain CB1006 carrying cloning vector pTrc200 (lane 2), pTrcB6 (lanes 3), or pTrcTraD (lanes 4) grown on AB minimal medium plates at 20°C in the absence of induction, in the presence of AS for virulence gene induction, or in the presence of AS and IPTG for simultaneous induction of the trc promoter. Cell lysates were subjected to SDS-PAGE under nonreducing conditions followed by Western blotting and detection with VirB7- and VirB9-specific antisera. Numbers on the right are molecular masses of reference proteins in kilodaltons.