FIG. 3.

Affinity immunoblot analysis demonstrates the binding of GST-LcrG to Thio-PcrV and of GST-LcrH to Thio-PopD. The protein samples from induced E. coli clones carrying the expression plasmids were loaded onto sodium dodecyl sulfate-4 to 12% bis-Tris polyacrylamide gels for electrophoresis. Protein was then electroblotted onto nitrocellulose membranes and incubated with each recombinant protein (8 to 10 μg/ml). The membranes were then developed with anti-GST antibodies conjugated with horseradish peroxidase and a chemiluminescent substrate. (A) An intense isolated band represents binding of GST-LcrG to Thio-PcrV. (B) An intense isolated band represents binding of GST-LcrH to Thio-PopD (arrowhead). IgG, immunoglobulin G.