FIG 3.

L. pneumophila Xer is encoded by lpg1867. Dot plots showing levels of intermolecular recombination between the chromosomal dif site and a plasmid containing the 22-bp att site as described for Fig. 2. (A) Intermolecular recombination in wild-type Lp02 and strains containing deletions of the dif site or one of six tyrosine-type recombinases. Shown in pink are the dif deletion strain and lpg1867 deletion strain, which both displayed levels of recombination below the limit of detection. (B) Intermolecular recombination in the wild-type and Δlpg1867 strains after transformation with plasmids expressing wild-type Lpg1867 or a predicted catalytic point mutant, Lpg1867-Y387F.