Pull-down assay for detection of VacA binding protein(s). Purified VacA was covalently coupled to CNBr-beads. Glycine-coated CNBr-beads were used as a negative control. Surface proteins in washed platelets were labeled with biotin. Platelets lysate was incubated with VacA bound or glycine bound beads. The beads were washed in lysis buffer, and proteins were eluted from the beads with SDS-reducing sample buffer. Eluted proteins were separated on SDS-PAGE, electroblotted, and proved with avidin-HRP (Figure 2) or with colloidal gold staining (data not shown). Left VacA beads, Right glycine beads.