Figure 4

Affinity purification of YopE-DHFR fusions using MTX-agarose. Yersiniae expressing DHFR fusions as indicated were lysed by French press treatment and soluble supernatants after centrifugation were incubated with MTX-agarose beads on ice for 30 min. Beads were washed with PBS five times, subsequently resuspended in SDS loading buffer and subjected to SDS-PAGE. Left panel represents a Coomassie stained gel, right panel a Western blot analysed with monoclonal anti-DHFR antiserum and polyclonal anti-SycE antiserum simultaneously. As control served Y. enterocolitica WA-314 harbouring plasmid pACYC184.