FIG. 3.

Conserved gene arrangement alignment of the tra gene cluster from the L. pneumophila serogroup 1 strain Philadelphia-1 LpPI-1 locus and the transfer region gene cluster of E. coli plasmid F. Genes from the LpPI-1 tra gene cluster that are homologous to the genes in the E. coli plasmid F transfer region and in an identical gene arrangement are gray, and genes that are present in the plasmid F transfer region but absent from the LpPI-1 tra gene cluster are black. The map of the transfer gene region of E. coli plasmid F is adapted from Frost et al. (16). See the text for details.