Fig. 5.

Bacterial two-hybrid assay used to detect protein-protein interactions. Pairs of plasmids encoding fusions of the indicated proteins to the T18 and T25 domains of adenylate cyclase were transformed into test strain DHM1. Transformants were streaked on X-Gal (5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside)-containing plates. Blue color reflects interaction between the fused proteins. C+ and C−, plasmids pT25zip + pUT18Czip and pUT18C, respectively. Abbreviations for fused proteins: B, R388 TrwB; point TrwB mutations are indicated in parentheses; E, TrwE-Bt; B10, B. henselae VirB10; D4, B. henselae VirD4.