FIG. 5.

Affinity blot and coimmunoprecipitation. (A) An affinity blot was performed as described in Materials and Methods. In this case, pure protein (2 μg) was subjected to SDS-17.5% PAGE, transferred to a nitrocellulose membrane, incubated with SltF, and probed with anti-SltF antibodies. (B) Coimmunoprecipitation assay showing specific interaction between SltF and FlgJ. Protein A-Sepharose beads to which specific anti-SltF gamma globulins were bound were incubated with FlgJ, SltF, or both proteins previously mixed. The retained proteins were subjected to SDS-PAGE and transferred to nitrocellulose membranes developed with anti-His₆ histidine commercial antibodies (see Materials and Methods).