FIG 4.

Specific mutations in the coiled-coil regions disrupt PilNO interaction. Core mutations corresponding to PilN ES132-133VA, MR141-142KL, and EV157-158AD, individually and in combination (Triple), failed to disrupt interactions between full-length PilN and PilO in the BTH assay. Mutations in the coiled coils PilN L81K and LD64-65KK and PilO M92K disrupted the interaction, whereas PilN L81A and L82K and PilO M92A had no effect. Experiments were performed in triplicate (n = 3). Bars represent the means ± standard errors. The red line indicates β-galactosidase activity of the vector-only negative control (Vector). The positive control was the full-length T18-PilN and T25-PilO interaction (white bar labeled “PilN”).