FIGURE 2.

Bacterial two-hybrid analysis of the BceRS-BceAB module. Hybrids consisting of B. pertussis CyaA T18 or T25 domains and each individual Bce protein or the complete transporter (BceAB) or TCS (BceRS) were introduced into E. coli BTH101. Cells were spotted onto LB plates containing X-Gal (40 μg/ml), isopropyl 1-thio-β-d-galactopyranoside (0.5 mm), and antibiotics for selection. Pictures were taken after 48 h of incubation at 30 °C. The blue colonies indicating positive results for interaction are depicted as dark gray in the grayscale image.