Fig 3.

Conjugative DNA transfer mediated by TrwC derivatives. Donor bacteria contained the plasmid coding for the Dtr region of R388 (oriT-trwABC) and a helper plasmid (pSU4058) to provide R388 T4SS. The TrwC variant in each construct is indicated at the bottom: TrwC*, a variant with different C-terminal 32 residues; double colons indicate domains fused to the C terminus; variants in TS motifs are indicated with asterisks (see the text for details). DNA transfer is expressed as the number of transconjugants per donor. The bars represent means of 5 independent experiments. The error bars indicate standard errors of the mean. Student's t test was used to analyze the data referred to the positive control, TrwC. *, P ≤ 0.01; **, P ≤ 0.001; ***, P ≤ 0.0001.