FIG. 3.

Interactions of recombinant VacA proteins with c-Myc-tagged p88 VacA. E. coli extracts containing the indicated recombinant VacA proteins were mixed with purified acid-activated c-Myc-tagged p88 wild-type VacA (p88c-Myc) from an H. pylori culture supernatant, as indicated (A, B, and D). Alternatively, E. coli extracts containing Δ6-27p33His or p55c-Myc were mixed together as indicated (C). Protein complexes were immunoprecipitated (I.P.) with an anti-c-Myc antibody, electrophoresed in a 10% sodium dodecyl sulfate-polyacrylamide gel, transferred to a nitrocellulose membrane, and immunoblotted (I.B.) with anti-His and anti-c-Myc antibodies, as indicated.