FIG. 6.

Efficient T4 secretion is sensitive to the relative concentration of T4CP and substrate protein. (A) Heterologous conjugation systems were tested for recognition and transfer of the C. fetus Fic proteins. The protein translocation frequencies (recombination events per donor) supported by R1-16, pOX38, R388, and RP4 conjugation systems are shown (black bars, right) for Cre alone or Cre fused to the full-length proteins indicated (left). DNA self-transfer frequencies for each plasmid system are indicated with gray bars. Standard deviations are shown. (B) DNA self-transfer of pOX38 is inhibited by cre-traI overexpression in trans (gray bars). By comparison, frequencies of gene and protein transfer are markedly increased when F traD and the cre-traI are both overexpressed in trans to traD-null derivative pOX38traD411.